| 1 | /************************************************* |
| 2 | * Exim - an Internet mail transport agent * |
| 3 | *************************************************/ |
| 4 | |
| 5 | /* Copyright (c) University of Cambridge 1995 - 2018 */ |
| 6 | /* See the file NOTICE for conditions of use and distribution. */ |
| 7 | |
| 8 | /* Functions for handling an incoming SMTP call. */ |
| 9 | |
| 10 | |
| 11 | #include "exim.h" |
| 12 | #include <assert.h> |
| 13 | |
| 14 | |
| 15 | /* Initialize for TCP wrappers if so configured. It appears that the macro |
| 16 | HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before |
| 17 | including that header, and restore its value afterwards. */ |
| 18 | |
| 19 | #ifdef USE_TCP_WRAPPERS |
| 20 | |
| 21 | #if HAVE_IPV6 |
| 22 | #define EXIM_HAVE_IPV6 |
| 23 | #endif |
| 24 | #undef HAVE_IPV6 |
| 25 | #include <tcpd.h> |
| 26 | #undef HAVE_IPV6 |
| 27 | #ifdef EXIM_HAVE_IPV6 |
| 28 | #define HAVE_IPV6 TRUE |
| 29 | #endif |
| 30 | |
| 31 | int allow_severity = LOG_INFO; |
| 32 | int deny_severity = LOG_NOTICE; |
| 33 | uschar *tcp_wrappers_name; |
| 34 | #endif |
| 35 | |
| 36 | |
| 37 | /* Size of buffer for reading SMTP commands. We used to use 512, as defined |
| 38 | by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP |
| 39 | commands that accept arguments, and this in particular applies to AUTH, where |
| 40 | the data can be quite long. More recently this value was 2048 in Exim; |
| 41 | however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients |
| 42 | such as Thunderbird will send an AUTH with an initial-response for GSSAPI. |
| 43 | The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and |
| 44 | we need room to handle large base64-encoded AUTHs for GSSAPI. |
| 45 | */ |
| 46 | |
| 47 | #define SMTP_CMD_BUFFER_SIZE 16384 |
| 48 | |
| 49 | /* Size of buffer for reading SMTP incoming packets */ |
| 50 | |
| 51 | #define IN_BUFFER_SIZE 8192 |
| 52 | |
| 53 | /* Structure for SMTP command list */ |
| 54 | |
| 55 | typedef struct { |
| 56 | const char *name; |
| 57 | int len; |
| 58 | short int cmd; |
| 59 | short int has_arg; |
| 60 | short int is_mail_cmd; |
| 61 | } smtp_cmd_list; |
| 62 | |
| 63 | /* Codes for identifying commands. We order them so that those that come first |
| 64 | are those for which synchronization is always required. Checking this can help |
| 65 | block some spam. */ |
| 66 | |
| 67 | enum { |
| 68 | /* These commands are required to be synchronized, i.e. to be the last in a |
| 69 | block of commands when pipelining. */ |
| 70 | |
| 71 | HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */ |
| 72 | VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */ |
| 73 | ETRN_CMD, /* This by analogy with TURN from the RFC */ |
| 74 | STARTTLS_CMD, /* Required by the STARTTLS RFC */ |
| 75 | TLS_AUTH_CMD, /* auto-command at start of SSL */ |
| 76 | |
| 77 | /* This is a dummy to identify the non-sync commands when pipelining */ |
| 78 | |
| 79 | NON_SYNC_CMD_PIPELINING, |
| 80 | |
| 81 | /* These commands need not be synchronized when pipelining */ |
| 82 | |
| 83 | MAIL_CMD, RCPT_CMD, RSET_CMD, |
| 84 | |
| 85 | /* This is a dummy to identify the non-sync commands when not pipelining */ |
| 86 | |
| 87 | NON_SYNC_CMD_NON_PIPELINING, |
| 88 | |
| 89 | /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and |
| 90 | processed the message is sent using a series of BDAT commands" |
| 91 | implies that BDAT should be synchronized. However, we see Google, at least, |
| 92 | sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for |
| 93 | processing of the RCPT response(s). We shall do the same, and not require |
| 94 | synch for BDAT. Worse, as the chunk may (very likely will) follow the |
| 95 | command-header in the same packet we cannot do the usual "is there any |
| 96 | follow-on data after the command line" even for non-pipeline mode. |
| 97 | So we'll need an explicit check after reading the expected chunk amount |
| 98 | when non-pipe, before sending the ACK. */ |
| 99 | |
| 100 | BDAT_CMD, |
| 101 | |
| 102 | /* I have been unable to find a statement about the use of pipelining |
| 103 | with AUTH, so to be on the safe side it is here, though I kind of feel |
| 104 | it should be up there with the synchronized commands. */ |
| 105 | |
| 106 | AUTH_CMD, |
| 107 | |
| 108 | /* I'm not sure about these, but I don't think they matter. */ |
| 109 | |
| 110 | QUIT_CMD, HELP_CMD, |
| 111 | |
| 112 | #ifdef SUPPORT_PROXY |
| 113 | PROXY_FAIL_IGNORE_CMD, |
| 114 | #endif |
| 115 | |
| 116 | /* These are specials that don't correspond to actual commands */ |
| 117 | |
| 118 | EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD, |
| 119 | TOO_MANY_NONMAIL_CMD }; |
| 120 | |
| 121 | |
| 122 | /* This is a convenience macro for adding the identity of an SMTP command |
| 123 | to the circular buffer that holds a list of the last n received. */ |
| 124 | |
| 125 | #define HAD(n) \ |
| 126 | smtp_connection_had[smtp_ch_index++] = n; \ |
| 127 | if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0 |
| 128 | |
| 129 | |
| 130 | /************************************************* |
| 131 | * Local static variables * |
| 132 | *************************************************/ |
| 133 | |
| 134 | static auth_instance *authenticated_by; |
| 135 | static BOOL auth_advertised; |
| 136 | #ifdef SUPPORT_TLS |
| 137 | static BOOL tls_advertised; |
| 138 | # ifdef EXPERIMENTAL_REQUIRETLS |
| 139 | static BOOL requiretls_advertised; |
| 140 | # endif |
| 141 | #endif |
| 142 | static BOOL dsn_advertised; |
| 143 | static BOOL esmtp; |
| 144 | static BOOL helo_required = FALSE; |
| 145 | static BOOL helo_verify = FALSE; |
| 146 | static BOOL helo_seen; |
| 147 | static BOOL helo_accept_junk; |
| 148 | static BOOL count_nonmail; |
| 149 | static BOOL rcpt_smtp_response_same; |
| 150 | static BOOL rcpt_in_progress; |
| 151 | static int nonmail_command_count; |
| 152 | static BOOL smtp_exit_function_called = 0; |
| 153 | #ifdef SUPPORT_I18N |
| 154 | static BOOL smtputf8_advertised; |
| 155 | #endif |
| 156 | static int synprot_error_count; |
| 157 | static int unknown_command_count; |
| 158 | static int sync_cmd_limit; |
| 159 | static int smtp_write_error = 0; |
| 160 | |
| 161 | static uschar *rcpt_smtp_response; |
| 162 | static uschar *smtp_data_buffer; |
| 163 | static uschar *smtp_cmd_data; |
| 164 | |
| 165 | /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their |
| 166 | final fields of all except AUTH are forced TRUE at the start of a new message |
| 167 | setup, to allow one of each between messages that is not counted as a nonmail |
| 168 | command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to |
| 169 | allow a new EHLO after starting up TLS. |
| 170 | |
| 171 | AUTH is "falsely" labelled as a mail command initially, so that it doesn't get |
| 172 | counted. However, the flag is changed when AUTH is received, so that multiple |
| 173 | failing AUTHs will eventually hit the limit. After a successful AUTH, another |
| 174 | AUTH is already forbidden. After a TLS session is started, AUTH's flag is again |
| 175 | forced TRUE, to allow for the re-authentication that can happen at that point. |
| 176 | |
| 177 | QUIT is also "falsely" labelled as a mail command so that it doesn't up the |
| 178 | count of non-mail commands and possibly provoke an error. |
| 179 | |
| 180 | tls_auth is a pseudo-command, never expected in input. It is activated |
| 181 | on TLS startup and looks for a tls authenticator. */ |
| 182 | |
| 183 | static smtp_cmd_list cmd_list[] = { |
| 184 | /* name len cmd has_arg is_mail_cmd */ |
| 185 | |
| 186 | { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */ |
| 187 | { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE }, |
| 188 | { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE }, |
| 189 | { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE }, |
| 190 | #ifdef SUPPORT_TLS |
| 191 | { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE }, |
| 192 | { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE }, |
| 193 | #endif |
| 194 | |
| 195 | /* If you change anything above here, also fix the definitions below. */ |
| 196 | |
| 197 | { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE }, |
| 198 | { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE }, |
| 199 | { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE }, |
| 200 | { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE }, |
| 201 | { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE }, |
| 202 | { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE }, |
| 203 | { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE }, |
| 204 | { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE }, |
| 205 | { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE }, |
| 206 | { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE } |
| 207 | }; |
| 208 | |
| 209 | static smtp_cmd_list *cmd_list_end = |
| 210 | cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list); |
| 211 | |
| 212 | #define CMD_LIST_RSET 0 |
| 213 | #define CMD_LIST_HELO 1 |
| 214 | #define CMD_LIST_EHLO 2 |
| 215 | #define CMD_LIST_AUTH 3 |
| 216 | #define CMD_LIST_STARTTLS 4 |
| 217 | #define CMD_LIST_TLS_AUTH 5 |
| 218 | |
| 219 | /* This list of names is used for performing the smtp_no_mail logging action. |
| 220 | It must be kept in step with the SCH_xxx enumerations. */ |
| 221 | |
| 222 | static uschar *smtp_names[] = |
| 223 | { |
| 224 | US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN", |
| 225 | US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", |
| 226 | US"STARTTLS", US"VRFY" }; |
| 227 | |
| 228 | static uschar *protocols_local[] = { |
| 229 | US"local-smtp", /* HELO */ |
| 230 | US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */ |
| 231 | US"local-esmtp", /* EHLO */ |
| 232 | US"local-esmtps", /* EHLO->STARTTLS->EHLO */ |
| 233 | US"local-esmtpa", /* EHLO->AUTH */ |
| 234 | US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */ |
| 235 | }; |
| 236 | static uschar *protocols[] = { |
| 237 | US"smtp", /* HELO */ |
| 238 | US"smtps", /* The rare case EHLO->STARTTLS->HELO */ |
| 239 | US"esmtp", /* EHLO */ |
| 240 | US"esmtps", /* EHLO->STARTTLS->EHLO */ |
| 241 | US"esmtpa", /* EHLO->AUTH */ |
| 242 | US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */ |
| 243 | }; |
| 244 | |
| 245 | #define pnormal 0 |
| 246 | #define pextend 2 |
| 247 | #define pcrpted 1 /* added to pextend or pnormal */ |
| 248 | #define pauthed 2 /* added to pextend */ |
| 249 | |
| 250 | /* Sanity check and validate optional args to MAIL FROM: envelope */ |
| 251 | enum { |
| 252 | ENV_MAIL_OPT_NULL, |
| 253 | ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH, |
| 254 | #ifndef DISABLE_PRDR |
| 255 | ENV_MAIL_OPT_PRDR, |
| 256 | #endif |
| 257 | ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID, |
| 258 | #ifdef SUPPORT_I18N |
| 259 | ENV_MAIL_OPT_UTF8, |
| 260 | #endif |
| 261 | #ifdef EXPERIMENTAL_REQUIRETLS |
| 262 | ENV_MAIL_OPT_REQTLS, |
| 263 | #endif |
| 264 | }; |
| 265 | typedef struct { |
| 266 | uschar * name; /* option requested during MAIL cmd */ |
| 267 | int value; /* enum type */ |
| 268 | BOOL need_value; /* TRUE requires value (name=value pair format) |
| 269 | FALSE is a singleton */ |
| 270 | } env_mail_type_t; |
| 271 | static env_mail_type_t env_mail_type_list[] = { |
| 272 | { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE }, |
| 273 | { US"BODY", ENV_MAIL_OPT_BODY, TRUE }, |
| 274 | { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE }, |
| 275 | #ifndef DISABLE_PRDR |
| 276 | { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE }, |
| 277 | #endif |
| 278 | { US"RET", ENV_MAIL_OPT_RET, TRUE }, |
| 279 | { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE }, |
| 280 | #ifdef SUPPORT_I18N |
| 281 | { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */ |
| 282 | #endif |
| 283 | #ifdef EXPERIMENTAL_REQUIRETLS |
| 284 | /* https://tools.ietf.org/html/draft-ietf-uta-smtp-require-tls-03 */ |
| 285 | { US"REQUIRETLS",ENV_MAIL_OPT_REQTLS, FALSE }, |
| 286 | #endif |
| 287 | /* keep this the last entry */ |
| 288 | { US"NULL", ENV_MAIL_OPT_NULL, FALSE }, |
| 289 | }; |
| 290 | |
| 291 | /* When reading SMTP from a remote host, we have to use our own versions of the |
| 292 | C input-reading functions, in order to be able to flush the SMTP output only |
| 293 | when about to read more data from the socket. This is the only way to get |
| 294 | optimal performance when the client is using pipelining. Flushing for every |
| 295 | command causes a separate packet and reply packet each time; saving all the |
| 296 | responses up (when pipelining) combines them into one packet and one response. |
| 297 | |
| 298 | For simplicity, these functions are used for *all* SMTP input, not only when |
| 299 | receiving over a socket. However, after setting up a secure socket (SSL), input |
| 300 | is read via the OpenSSL library, and another set of functions is used instead |
| 301 | (see tls.c). |
| 302 | |
| 303 | These functions are set in the receive_getc etc. variables and called with the |
| 304 | same interface as the C functions. However, since there can only ever be |
| 305 | one incoming SMTP call, we just use a single buffer and flags. There is no need |
| 306 | to implement a complicated private FILE-like structure.*/ |
| 307 | |
| 308 | static uschar *smtp_inbuffer; |
| 309 | static uschar *smtp_inptr; |
| 310 | static uschar *smtp_inend; |
| 311 | static int smtp_had_eof; |
| 312 | static int smtp_had_error; |
| 313 | |
| 314 | |
| 315 | /* forward declarations */ |
| 316 | static int smtp_read_command(BOOL check_sync, unsigned buffer_lim); |
| 317 | static int synprot_error(int type, int code, uschar *data, uschar *errmess); |
| 318 | static void smtp_quit_handler(uschar **, uschar **); |
| 319 | static void smtp_rset_handler(void); |
| 320 | |
| 321 | /************************************************* |
| 322 | * Recheck synchronization * |
| 323 | *************************************************/ |
| 324 | |
| 325 | /* Synchronization checks can never be perfect because a packet may be on its |
| 326 | way but not arrived when the check is done. Normally, the checks happen when |
| 327 | commands are read: Exim ensures that there is no more input in the input buffer. |
| 328 | In normal cases, the response to the command will be fast, and there is no |
| 329 | further check. |
| 330 | |
| 331 | However, for some commands an ACL is run, and that can include delays. In those |
| 332 | cases, it is useful to do another check on the input just before sending the |
| 333 | response. This also applies at the start of a connection. This function does |
| 334 | that check by means of the select() function, as long as the facility is not |
| 335 | disabled or inappropriate. A failure of select() is ignored. |
| 336 | |
| 337 | When there is unwanted input, we read it so that it appears in the log of the |
| 338 | error. |
| 339 | |
| 340 | Arguments: none |
| 341 | Returns: TRUE if all is well; FALSE if there is input pending |
| 342 | */ |
| 343 | |
| 344 | static BOOL |
| 345 | wouldblock_reading(void) |
| 346 | { |
| 347 | int fd, rc; |
| 348 | fd_set fds; |
| 349 | struct timeval tzero; |
| 350 | |
| 351 | #ifdef SUPPORT_TLS |
| 352 | if (tls_in.active.sock >= 0) |
| 353 | return !tls_could_read(); |
| 354 | #endif |
| 355 | |
| 356 | if (smtp_inptr < smtp_inend) |
| 357 | return FALSE; |
| 358 | |
| 359 | fd = fileno(smtp_in); |
| 360 | FD_ZERO(&fds); |
| 361 | FD_SET(fd, &fds); |
| 362 | tzero.tv_sec = 0; |
| 363 | tzero.tv_usec = 0; |
| 364 | rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero); |
| 365 | |
| 366 | if (rc <= 0) return TRUE; /* Not ready to read */ |
| 367 | rc = smtp_getc(GETC_BUFFER_UNLIMITED); |
| 368 | if (rc < 0) return TRUE; /* End of file or error */ |
| 369 | |
| 370 | smtp_ungetc(rc); |
| 371 | return FALSE; |
| 372 | } |
| 373 | |
| 374 | static BOOL |
| 375 | check_sync(void) |
| 376 | { |
| 377 | if (!smtp_enforce_sync || !sender_host_address || sender_host_notsocket) |
| 378 | return TRUE; |
| 379 | |
| 380 | return wouldblock_reading(); |
| 381 | } |
| 382 | |
| 383 | |
| 384 | /* If there's input waiting (and we're doing pipelineing) then we can pipeline |
| 385 | a reponse with the one following. */ |
| 386 | |
| 387 | static BOOL |
| 388 | pipeline_response(void) |
| 389 | { |
| 390 | if ( !smtp_enforce_sync || !sender_host_address |
| 391 | || sender_host_notsocket || !smtp_in_pipelining_advertised) |
| 392 | return FALSE; |
| 393 | |
| 394 | return !wouldblock_reading(); |
| 395 | } |
| 396 | |
| 397 | |
| 398 | |
| 399 | /************************************************* |
| 400 | * Log incomplete transactions * |
| 401 | *************************************************/ |
| 402 | |
| 403 | /* This function is called after a transaction has been aborted by RSET, QUIT, |
| 404 | connection drops or other errors. It logs the envelope information received |
| 405 | so far in order to preserve address verification attempts. |
| 406 | |
| 407 | Argument: string to indicate what aborted the transaction |
| 408 | Returns: nothing |
| 409 | */ |
| 410 | |
| 411 | static void |
| 412 | incomplete_transaction_log(uschar *what) |
| 413 | { |
| 414 | if (sender_address == NULL || /* No transaction in progress */ |
| 415 | !LOGGING(smtp_incomplete_transaction)) |
| 416 | return; |
| 417 | |
| 418 | /* Build list of recipients for logging */ |
| 419 | |
| 420 | if (recipients_count > 0) |
| 421 | { |
| 422 | int i; |
| 423 | raw_recipients = store_get(recipients_count * sizeof(uschar *)); |
| 424 | for (i = 0; i < recipients_count; i++) |
| 425 | raw_recipients[i] = recipients_list[i].address; |
| 426 | raw_recipients_count = recipients_count; |
| 427 | } |
| 428 | |
| 429 | log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS, |
| 430 | "%s incomplete transaction (%s)", host_and_ident(TRUE), what); |
| 431 | } |
| 432 | |
| 433 | |
| 434 | |
| 435 | |
| 436 | void |
| 437 | smtp_command_timeout_exit(void) |
| 438 | { |
| 439 | log_write(L_lost_incoming_connection, |
| 440 | LOG_MAIN, "SMTP command timeout on%s connection from %s", |
| 441 | tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE)); |
| 442 | if (smtp_batched_input) |
| 443 | moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */ |
| 444 | smtp_notquit_exit(US"command-timeout", US"421", |
| 445 | US"%s: SMTP command timeout - closing connection", |
| 446 | smtp_active_hostname); |
| 447 | exim_exit(EXIT_FAILURE, US"receiving"); |
| 448 | } |
| 449 | |
| 450 | void |
| 451 | smtp_command_sigterm_exit(void) |
| 452 | { |
| 453 | log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info()); |
| 454 | if (smtp_batched_input) |
| 455 | moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */ |
| 456 | smtp_notquit_exit(US"signal-exit", US"421", |
| 457 | US"%s: Service not available - closing connection", smtp_active_hostname); |
| 458 | exim_exit(EXIT_FAILURE, US"receiving"); |
| 459 | } |
| 460 | |
| 461 | void |
| 462 | smtp_data_timeout_exit(void) |
| 463 | { |
| 464 | log_write(L_lost_incoming_connection, |
| 465 | LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>", |
| 466 | sender_fullhost ? sender_fullhost : US"local process", sender_address); |
| 467 | receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout"); |
| 468 | /* Does not return */ |
| 469 | } |
| 470 | |
| 471 | void |
| 472 | smtp_data_sigint_exit(void) |
| 473 | { |
| 474 | log_write(0, LOG_MAIN, "%s closed after %s", |
| 475 | smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT"); |
| 476 | receive_bomb_out(US"signal-exit", |
| 477 | US"Service not available - SIGTERM or SIGINT received"); |
| 478 | /* Does not return */ |
| 479 | } |
| 480 | |
| 481 | |
| 482 | |
| 483 | /* Refill the buffer, and notify DKIM verification code. |
| 484 | Return false for error or EOF. |
| 485 | */ |
| 486 | |
| 487 | static BOOL |
| 488 | smtp_refill(unsigned lim) |
| 489 | { |
| 490 | int rc, save_errno; |
| 491 | if (!smtp_out) return FALSE; |
| 492 | fflush(smtp_out); |
| 493 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); |
| 494 | |
| 495 | /* Limit amount read, so non-message data is not fed to DKIM. |
| 496 | Take care to not touch the safety NUL at the end of the buffer. */ |
| 497 | |
| 498 | rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim)); |
| 499 | save_errno = errno; |
| 500 | if (smtp_receive_timeout > 0) alarm(0); |
| 501 | if (rc <= 0) |
| 502 | { |
| 503 | /* Must put the error text in fixed store, because this might be during |
| 504 | header reading, where it releases unused store above the header. */ |
| 505 | if (rc < 0) |
| 506 | { |
| 507 | if (had_command_timeout) /* set by signal handler */ |
| 508 | smtp_command_timeout_exit(); /* does not return */ |
| 509 | if (had_command_sigterm) |
| 510 | smtp_command_sigterm_exit(); |
| 511 | if (had_data_timeout) |
| 512 | smtp_data_timeout_exit(); |
| 513 | if (had_data_sigint) |
| 514 | smtp_data_sigint_exit(); |
| 515 | |
| 516 | smtp_had_error = save_errno; |
| 517 | smtp_read_error = string_copy_malloc( |
| 518 | string_sprintf(" (error: %s)", strerror(save_errno))); |
| 519 | } |
| 520 | else |
| 521 | smtp_had_eof = 1; |
| 522 | return FALSE; |
| 523 | } |
| 524 | #ifndef DISABLE_DKIM |
| 525 | dkim_exim_verify_feed(smtp_inbuffer, rc); |
| 526 | #endif |
| 527 | smtp_inend = smtp_inbuffer + rc; |
| 528 | smtp_inptr = smtp_inbuffer; |
| 529 | return TRUE; |
| 530 | } |
| 531 | |
| 532 | /************************************************* |
| 533 | * SMTP version of getc() * |
| 534 | *************************************************/ |
| 535 | |
| 536 | /* This gets the next byte from the SMTP input buffer. If the buffer is empty, |
| 537 | it flushes the output, and refills the buffer, with a timeout. The signal |
| 538 | handler is set appropriately by the calling function. This function is not used |
| 539 | after a connection has negotiated itself into an TLS/SSL state. |
| 540 | |
| 541 | Arguments: lim Maximum amount to read/buffer |
| 542 | Returns: the next character or EOF |
| 543 | */ |
| 544 | |
| 545 | int |
| 546 | smtp_getc(unsigned lim) |
| 547 | { |
| 548 | if (smtp_inptr >= smtp_inend) |
| 549 | if (!smtp_refill(lim)) |
| 550 | return EOF; |
| 551 | return *smtp_inptr++; |
| 552 | } |
| 553 | |
| 554 | uschar * |
| 555 | smtp_getbuf(unsigned * len) |
| 556 | { |
| 557 | unsigned size; |
| 558 | uschar * buf; |
| 559 | |
| 560 | if (smtp_inptr >= smtp_inend) |
| 561 | if (!smtp_refill(*len)) |
| 562 | { *len = 0; return NULL; } |
| 563 | |
| 564 | if ((size = smtp_inend - smtp_inptr) > *len) size = *len; |
| 565 | buf = smtp_inptr; |
| 566 | smtp_inptr += size; |
| 567 | *len = size; |
| 568 | return buf; |
| 569 | } |
| 570 | |
| 571 | void |
| 572 | smtp_get_cache(void) |
| 573 | { |
| 574 | #ifndef DISABLE_DKIM |
| 575 | int n = smtp_inend - smtp_inptr; |
| 576 | if (n > 0) |
| 577 | dkim_exim_verify_feed(smtp_inptr, n); |
| 578 | #endif |
| 579 | } |
| 580 | |
| 581 | |
| 582 | /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the |
| 583 | previous BDAT chunk and getting new ones when we run out. Uses the |
| 584 | underlying smtp_getc or tls_getc both for that and for getting the |
| 585 | (buffered) data byte. EOD signals (an expected) no further data. |
| 586 | ERR signals a protocol error, and EOF a closed input stream. |
| 587 | |
| 588 | Called from read_bdat_smtp() in receive.c for the message body, but also |
| 589 | by the headers read loop in receive_msg(); manipulates chunking_state |
| 590 | to handle the BDAT command/response. |
| 591 | Placed here due to the correlation with the above smtp_getc(), which it wraps, |
| 592 | and also by the need to do smtp command/response handling. |
| 593 | |
| 594 | Arguments: lim (ignored) |
| 595 | Returns: the next character or ERR, EOD or EOF |
| 596 | */ |
| 597 | |
| 598 | int |
| 599 | bdat_getc(unsigned lim) |
| 600 | { |
| 601 | uschar * user_msg = NULL; |
| 602 | uschar * log_msg; |
| 603 | |
| 604 | for(;;) |
| 605 | { |
| 606 | #ifndef DISABLE_DKIM |
| 607 | unsigned dkim_save; |
| 608 | #endif |
| 609 | |
| 610 | if (chunking_data_left > 0) |
| 611 | return lwr_receive_getc(chunking_data_left--); |
| 612 | |
| 613 | receive_getc = lwr_receive_getc; |
| 614 | receive_getbuf = lwr_receive_getbuf; |
| 615 | receive_ungetc = lwr_receive_ungetc; |
| 616 | #ifndef DISABLE_DKIM |
| 617 | dkim_save = dkim_collect_input; |
| 618 | dkim_collect_input = 0; |
| 619 | #endif |
| 620 | |
| 621 | /* Unless PIPELINING was offered, there should be no next command |
| 622 | until after we ack that chunk */ |
| 623 | |
| 624 | if (!smtp_in_pipelining_advertised && !check_sync()) |
| 625 | { |
| 626 | unsigned n = smtp_inend - smtp_inptr; |
| 627 | if (n > 32) n = 32; |
| 628 | |
| 629 | incomplete_transaction_log(US"sync failure"); |
| 630 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error " |
| 631 | "(next input sent too soon: pipelining was not advertised): " |
| 632 | "rejected \"%s\" %s next input=\"%s\"%s", |
| 633 | smtp_cmd_buffer, host_and_ident(TRUE), |
| 634 | string_printing(string_copyn(smtp_inptr, n)), |
| 635 | smtp_inend - smtp_inptr > n ? "..." : ""); |
| 636 | (void) synprot_error(L_smtp_protocol_error, 554, NULL, |
| 637 | US"SMTP synchronization error"); |
| 638 | goto repeat_until_rset; |
| 639 | } |
| 640 | |
| 641 | /* If not the last, ack the received chunk. The last response is delayed |
| 642 | until after the data ACL decides on it */ |
| 643 | |
| 644 | if (chunking_state == CHUNKING_LAST) |
| 645 | { |
| 646 | #ifndef DISABLE_DKIM |
| 647 | dkim_exim_verify_feed(NULL, 0); /* notify EOD */ |
| 648 | #endif |
| 649 | return EOD; |
| 650 | } |
| 651 | |
| 652 | smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize); |
| 653 | chunking_state = CHUNKING_OFFERED; |
| 654 | DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state); |
| 655 | |
| 656 | /* Expect another BDAT cmd from input. RFC 3030 says nothing about |
| 657 | QUIT, RSET or NOOP but handling them seems obvious */ |
| 658 | |
| 659 | next_cmd: |
| 660 | switch(smtp_read_command(TRUE, 1)) |
| 661 | { |
| 662 | default: |
| 663 | (void) synprot_error(L_smtp_protocol_error, 503, NULL, |
| 664 | US"only BDAT permissible after non-LAST BDAT"); |
| 665 | |
| 666 | repeat_until_rset: |
| 667 | switch(smtp_read_command(TRUE, 1)) |
| 668 | { |
| 669 | case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */ |
| 670 | case EOF_CMD: return EOF; |
| 671 | case RSET_CMD: smtp_rset_handler(); return ERR; |
| 672 | default: if (synprot_error(L_smtp_protocol_error, 503, NULL, |
| 673 | US"only RSET accepted now") > 0) |
| 674 | return EOF; |
| 675 | goto repeat_until_rset; |
| 676 | } |
| 677 | |
| 678 | case QUIT_CMD: |
| 679 | smtp_quit_handler(&user_msg, &log_msg); |
| 680 | /*FALLTHROUGH*/ |
| 681 | case EOF_CMD: |
| 682 | return EOF; |
| 683 | |
| 684 | case RSET_CMD: |
| 685 | smtp_rset_handler(); |
| 686 | return ERR; |
| 687 | |
| 688 | case NOOP_CMD: |
| 689 | HAD(SCH_NOOP); |
| 690 | smtp_printf("250 OK\r\n", FALSE); |
| 691 | goto next_cmd; |
| 692 | |
| 693 | case BDAT_CMD: |
| 694 | { |
| 695 | int n; |
| 696 | |
| 697 | if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1) |
| 698 | { |
| 699 | (void) synprot_error(L_smtp_protocol_error, 501, NULL, |
| 700 | US"missing size for BDAT command"); |
| 701 | return ERR; |
| 702 | } |
| 703 | chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0 |
| 704 | ? CHUNKING_LAST : CHUNKING_ACTIVE; |
| 705 | chunking_data_left = chunking_datasize; |
| 706 | DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n", |
| 707 | (int)chunking_state, chunking_data_left); |
| 708 | |
| 709 | if (chunking_datasize == 0) |
| 710 | if (chunking_state == CHUNKING_LAST) |
| 711 | return EOD; |
| 712 | else |
| 713 | { |
| 714 | (void) synprot_error(L_smtp_protocol_error, 504, NULL, |
| 715 | US"zero size for BDAT command"); |
| 716 | goto repeat_until_rset; |
| 717 | } |
| 718 | |
| 719 | receive_getc = bdat_getc; |
| 720 | receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */ |
| 721 | receive_ungetc = bdat_ungetc; |
| 722 | #ifndef DISABLE_DKIM |
| 723 | dkim_collect_input = dkim_save; |
| 724 | #endif |
| 725 | break; /* to top of main loop */ |
| 726 | } |
| 727 | } |
| 728 | } |
| 729 | } |
| 730 | |
| 731 | uschar * |
| 732 | bdat_getbuf(unsigned * len) |
| 733 | { |
| 734 | uschar * buf; |
| 735 | |
| 736 | if (chunking_data_left <= 0) |
| 737 | { *len = 0; return NULL; } |
| 738 | |
| 739 | if (*len > chunking_data_left) *len = chunking_data_left; |
| 740 | buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */ |
| 741 | chunking_data_left -= *len; |
| 742 | return buf; |
| 743 | } |
| 744 | |
| 745 | void |
| 746 | bdat_flush_data(void) |
| 747 | { |
| 748 | while (chunking_data_left) |
| 749 | { |
| 750 | unsigned n = chunking_data_left; |
| 751 | if (!bdat_getbuf(&n)) break; |
| 752 | } |
| 753 | |
| 754 | receive_getc = lwr_receive_getc; |
| 755 | receive_getbuf = lwr_receive_getbuf; |
| 756 | receive_ungetc = lwr_receive_ungetc; |
| 757 | |
| 758 | if (chunking_state != CHUNKING_LAST) |
| 759 | { |
| 760 | chunking_state = CHUNKING_OFFERED; |
| 761 | DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state); |
| 762 | } |
| 763 | } |
| 764 | |
| 765 | |
| 766 | |
| 767 | |
| 768 | /************************************************* |
| 769 | * SMTP version of ungetc() * |
| 770 | *************************************************/ |
| 771 | |
| 772 | /* Puts a character back in the input buffer. Only ever |
| 773 | called once. |
| 774 | |
| 775 | Arguments: |
| 776 | ch the character |
| 777 | |
| 778 | Returns: the character |
| 779 | */ |
| 780 | |
| 781 | int |
| 782 | smtp_ungetc(int ch) |
| 783 | { |
| 784 | *--smtp_inptr = ch; |
| 785 | return ch; |
| 786 | } |
| 787 | |
| 788 | |
| 789 | int |
| 790 | bdat_ungetc(int ch) |
| 791 | { |
| 792 | chunking_data_left++; |
| 793 | return lwr_receive_ungetc(ch); |
| 794 | } |
| 795 | |
| 796 | |
| 797 | |
| 798 | /************************************************* |
| 799 | * SMTP version of feof() * |
| 800 | *************************************************/ |
| 801 | |
| 802 | /* Tests for a previous EOF |
| 803 | |
| 804 | Arguments: none |
| 805 | Returns: non-zero if the eof flag is set |
| 806 | */ |
| 807 | |
| 808 | int |
| 809 | smtp_feof(void) |
| 810 | { |
| 811 | return smtp_had_eof; |
| 812 | } |
| 813 | |
| 814 | |
| 815 | |
| 816 | |
| 817 | /************************************************* |
| 818 | * SMTP version of ferror() * |
| 819 | *************************************************/ |
| 820 | |
| 821 | /* Tests for a previous read error, and returns with errno |
| 822 | restored to what it was when the error was detected. |
| 823 | |
| 824 | Arguments: none |
| 825 | Returns: non-zero if the error flag is set |
| 826 | */ |
| 827 | |
| 828 | int |
| 829 | smtp_ferror(void) |
| 830 | { |
| 831 | errno = smtp_had_error; |
| 832 | return smtp_had_error; |
| 833 | } |
| 834 | |
| 835 | |
| 836 | |
| 837 | /************************************************* |
| 838 | * Test for characters in the SMTP buffer * |
| 839 | *************************************************/ |
| 840 | |
| 841 | /* Used at the end of a message |
| 842 | |
| 843 | Arguments: none |
| 844 | Returns: TRUE/FALSE |
| 845 | */ |
| 846 | |
| 847 | BOOL |
| 848 | smtp_buffered(void) |
| 849 | { |
| 850 | return smtp_inptr < smtp_inend; |
| 851 | } |
| 852 | |
| 853 | |
| 854 | |
| 855 | /************************************************* |
| 856 | * Write formatted string to SMTP channel * |
| 857 | *************************************************/ |
| 858 | |
| 859 | /* This is a separate function so that we don't have to repeat everything for |
| 860 | TLS support or debugging. It is global so that the daemon and the |
| 861 | authentication functions can use it. It does not return any error indication, |
| 862 | because major problems such as dropped connections won't show up till an output |
| 863 | flush for non-TLS connections. The smtp_fflush() function is available for |
| 864 | checking that: for convenience, TLS output errors are remembered here so that |
| 865 | they are also picked up later by smtp_fflush(). |
| 866 | |
| 867 | Arguments: |
| 868 | format format string |
| 869 | more further data expected |
| 870 | ... optional arguments |
| 871 | |
| 872 | Returns: nothing |
| 873 | */ |
| 874 | |
| 875 | void |
| 876 | smtp_printf(const char *format, BOOL more, ...) |
| 877 | { |
| 878 | va_list ap; |
| 879 | |
| 880 | va_start(ap, more); |
| 881 | smtp_vprintf(format, more, ap); |
| 882 | va_end(ap); |
| 883 | } |
| 884 | |
| 885 | /* This is split off so that verify.c:respond_printf() can, in effect, call |
| 886 | smtp_printf(), bearing in mind that in C a vararg function can't directly |
| 887 | call another vararg function, only a function which accepts a va_list. */ |
| 888 | |
| 889 | void |
| 890 | smtp_vprintf(const char *format, BOOL more, va_list ap) |
| 891 | { |
| 892 | BOOL yield; |
| 893 | |
| 894 | yield = string_vformat(big_buffer, big_buffer_size, format, ap); |
| 895 | |
| 896 | DEBUG(D_receive) |
| 897 | { |
| 898 | void *reset_point = store_get(0); |
| 899 | uschar *msg_copy, *cr, *end; |
| 900 | msg_copy = string_copy(big_buffer); |
| 901 | end = msg_copy + Ustrlen(msg_copy); |
| 902 | while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */ |
| 903 | memmove(cr, cr + 1, (end--) - cr); |
| 904 | debug_printf("SMTP>> %s", msg_copy); |
| 905 | store_reset(reset_point); |
| 906 | } |
| 907 | |
| 908 | if (!yield) |
| 909 | { |
| 910 | log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()"); |
| 911 | smtp_closedown(US"Unexpected error"); |
| 912 | exim_exit(EXIT_FAILURE, NULL); |
| 913 | } |
| 914 | |
| 915 | /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs |
| 916 | have had the same. Note: this code is also present in smtp_respond(). It would |
| 917 | be tidier to have it only in one place, but when it was added, it was easier to |
| 918 | do it that way, so as not to have to mess with the code for the RCPT command, |
| 919 | which sometimes uses smtp_printf() and sometimes smtp_respond(). */ |
| 920 | |
| 921 | if (rcpt_in_progress) |
| 922 | { |
| 923 | if (rcpt_smtp_response == NULL) |
| 924 | rcpt_smtp_response = string_copy(big_buffer); |
| 925 | else if (rcpt_smtp_response_same && |
| 926 | Ustrcmp(rcpt_smtp_response, big_buffer) != 0) |
| 927 | rcpt_smtp_response_same = FALSE; |
| 928 | rcpt_in_progress = FALSE; |
| 929 | } |
| 930 | |
| 931 | /* Now write the string */ |
| 932 | |
| 933 | #ifdef SUPPORT_TLS |
| 934 | if (tls_in.active.sock >= 0) |
| 935 | { |
| 936 | if (tls_write(NULL, big_buffer, Ustrlen(big_buffer), more) < 0) |
| 937 | smtp_write_error = -1; |
| 938 | } |
| 939 | else |
| 940 | #endif |
| 941 | |
| 942 | if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1; |
| 943 | } |
| 944 | |
| 945 | |
| 946 | |
| 947 | /************************************************* |
| 948 | * Flush SMTP out and check for error * |
| 949 | *************************************************/ |
| 950 | |
| 951 | /* This function isn't currently used within Exim (it detects errors when it |
| 952 | tries to read the next SMTP input), but is available for use in local_scan(). |
| 953 | For non-TLS connections, it flushes the output and checks for errors. For |
| 954 | TLS-connections, it checks for a previously-detected TLS write error. |
| 955 | |
| 956 | Arguments: none |
| 957 | Returns: 0 for no error; -1 after an error |
| 958 | */ |
| 959 | |
| 960 | int |
| 961 | smtp_fflush(void) |
| 962 | { |
| 963 | if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1; |
| 964 | return smtp_write_error; |
| 965 | } |
| 966 | |
| 967 | |
| 968 | |
| 969 | /************************************************* |
| 970 | * SMTP command read timeout * |
| 971 | *************************************************/ |
| 972 | |
| 973 | /* Signal handler for timing out incoming SMTP commands. This attempts to |
| 974 | finish off tidily. |
| 975 | |
| 976 | Argument: signal number (SIGALRM) |
| 977 | Returns: nothing |
| 978 | */ |
| 979 | |
| 980 | static void |
| 981 | command_timeout_handler(int sig) |
| 982 | { |
| 983 | had_command_timeout = sig; |
| 984 | } |
| 985 | |
| 986 | |
| 987 | |
| 988 | /************************************************* |
| 989 | * SIGTERM received * |
| 990 | *************************************************/ |
| 991 | |
| 992 | /* Signal handler for handling SIGTERM. Again, try to finish tidily. |
| 993 | |
| 994 | Argument: signal number (SIGTERM) |
| 995 | Returns: nothing |
| 996 | */ |
| 997 | |
| 998 | static void |
| 999 | command_sigterm_handler(int sig) |
| 1000 | { |
| 1001 | had_command_sigterm = sig; |
| 1002 | } |
| 1003 | |
| 1004 | |
| 1005 | |
| 1006 | |
| 1007 | #ifdef SUPPORT_PROXY |
| 1008 | /************************************************* |
| 1009 | * Restore socket timeout to previous value * |
| 1010 | *************************************************/ |
| 1011 | /* If the previous value was successfully retrieved, restore |
| 1012 | it before returning control to the non-proxy routines |
| 1013 | |
| 1014 | Arguments: fd - File descriptor for input |
| 1015 | get_ok - Successfully retrieved previous values |
| 1016 | tvtmp - Time struct with previous values |
| 1017 | vslen - Length of time struct |
| 1018 | Returns: none |
| 1019 | */ |
| 1020 | static void |
| 1021 | restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen) |
| 1022 | { |
| 1023 | if (get_ok == 0) |
| 1024 | (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen); |
| 1025 | } |
| 1026 | |
| 1027 | /************************************************* |
| 1028 | * Check if host is required proxy host * |
| 1029 | *************************************************/ |
| 1030 | /* The function determines if inbound host will be a regular smtp host |
| 1031 | or if it is configured that it must use Proxy Protocol. A local |
| 1032 | connection cannot. |
| 1033 | |
| 1034 | Arguments: none |
| 1035 | Returns: bool |
| 1036 | */ |
| 1037 | |
| 1038 | static BOOL |
| 1039 | check_proxy_protocol_host() |
| 1040 | { |
| 1041 | int rc; |
| 1042 | |
| 1043 | if ( sender_host_address |
| 1044 | && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL, |
| 1045 | sender_host_address, NULL)) == OK) |
| 1046 | { |
| 1047 | DEBUG(D_receive) |
| 1048 | debug_printf("Detected proxy protocol configured host\n"); |
| 1049 | proxy_session = TRUE; |
| 1050 | } |
| 1051 | return proxy_session; |
| 1052 | } |
| 1053 | |
| 1054 | |
| 1055 | /************************************************* |
| 1056 | * Read data until newline or end of buffer * |
| 1057 | *************************************************/ |
| 1058 | /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't |
| 1059 | read an entire buffer and assume there will be nothing past a proxy protocol |
| 1060 | header. Our approach normally is to use stdio, but again that relies upon |
| 1061 | "STARTTLS\r\n" and a server response before the client starts TLS handshake, or |
| 1062 | reading _nothing_ before client TLS handshake. So we don't want to use the |
| 1063 | usual buffering reads which may read enough to block TLS starting. |
| 1064 | |
| 1065 | So unfortunately we're down to "read one byte at a time, with a syscall each, |
| 1066 | and expect a little overhead", for all proxy-opened connections which are v1, |
| 1067 | just to handle the TLS-on-connect case. Since SSL functions wrap the |
| 1068 | underlying fd, we can't assume that we can feed them any already-read content. |
| 1069 | |
| 1070 | We need to know where to read to, the max capacity, and we'll read until we |
| 1071 | get a CR and one more character. Let the caller scream if it's CR+!LF. |
| 1072 | |
| 1073 | Return the amount read. |
| 1074 | */ |
| 1075 | |
| 1076 | static int |
| 1077 | swallow_until_crlf(int fd, uschar *base, int already, int capacity) |
| 1078 | { |
| 1079 | uschar *to = base + already; |
| 1080 | uschar *cr; |
| 1081 | int have = 0; |
| 1082 | int ret; |
| 1083 | int last = 0; |
| 1084 | |
| 1085 | /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read |
| 1086 | up through the \r; for the _normal_ case, we haven't yet seen the \r. */ |
| 1087 | |
| 1088 | cr = memchr(base, '\r', already); |
| 1089 | if (cr != NULL) |
| 1090 | { |
| 1091 | if ((cr - base) < already - 1) |
| 1092 | { |
| 1093 | /* \r and presumed \n already within what we have; probably not |
| 1094 | actually proxy protocol, but abort cleanly. */ |
| 1095 | return 0; |
| 1096 | } |
| 1097 | /* \r is last character read, just need one more. */ |
| 1098 | last = 1; |
| 1099 | } |
| 1100 | |
| 1101 | while (capacity > 0) |
| 1102 | { |
| 1103 | do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR); |
| 1104 | if (ret == -1) |
| 1105 | return -1; |
| 1106 | have++; |
| 1107 | if (last) |
| 1108 | return have; |
| 1109 | if (*to == '\r') |
| 1110 | last = 1; |
| 1111 | capacity--; |
| 1112 | to++; |
| 1113 | } |
| 1114 | |
| 1115 | /* reached end without having room for a final newline, abort */ |
| 1116 | errno = EOVERFLOW; |
| 1117 | return -1; |
| 1118 | } |
| 1119 | |
| 1120 | /************************************************* |
| 1121 | * Setup host for proxy protocol * |
| 1122 | *************************************************/ |
| 1123 | /* The function configures the connection based on a header from the |
| 1124 | inbound host to use Proxy Protocol. The specification is very exact |
| 1125 | so exit with an error if do not find the exact required pieces. This |
| 1126 | includes an incorrect number of spaces separating args. |
| 1127 | |
| 1128 | Arguments: none |
| 1129 | Returns: Boolean success |
| 1130 | */ |
| 1131 | |
| 1132 | static void |
| 1133 | setup_proxy_protocol_host() |
| 1134 | { |
| 1135 | union { |
| 1136 | struct { |
| 1137 | uschar line[108]; |
| 1138 | } v1; |
| 1139 | struct { |
| 1140 | uschar sig[12]; |
| 1141 | uint8_t ver_cmd; |
| 1142 | uint8_t fam; |
| 1143 | uint16_t len; |
| 1144 | union { |
| 1145 | struct { /* TCP/UDP over IPv4, len = 12 */ |
| 1146 | uint32_t src_addr; |
| 1147 | uint32_t dst_addr; |
| 1148 | uint16_t src_port; |
| 1149 | uint16_t dst_port; |
| 1150 | } ip4; |
| 1151 | struct { /* TCP/UDP over IPv6, len = 36 */ |
| 1152 | uint8_t src_addr[16]; |
| 1153 | uint8_t dst_addr[16]; |
| 1154 | uint16_t src_port; |
| 1155 | uint16_t dst_port; |
| 1156 | } ip6; |
| 1157 | struct { /* AF_UNIX sockets, len = 216 */ |
| 1158 | uschar src_addr[108]; |
| 1159 | uschar dst_addr[108]; |
| 1160 | } unx; |
| 1161 | } addr; |
| 1162 | } v2; |
| 1163 | } hdr; |
| 1164 | |
| 1165 | /* Temp variables used in PPv2 address:port parsing */ |
| 1166 | uint16_t tmpport; |
| 1167 | char tmpip[INET_ADDRSTRLEN]; |
| 1168 | struct sockaddr_in tmpaddr; |
| 1169 | char tmpip6[INET6_ADDRSTRLEN]; |
| 1170 | struct sockaddr_in6 tmpaddr6; |
| 1171 | |
| 1172 | /* We can't read "all data until end" because while SMTP is |
| 1173 | server-speaks-first, the TLS handshake is client-speaks-first, so for |
| 1174 | TLS-on-connect ports the proxy protocol header will usually be immediately |
| 1175 | followed by a TLS handshake, and with N TLS libraries, we can't reliably |
| 1176 | reinject data for reading by those. So instead we first read "enough to be |
| 1177 | safely read within the header, and figure out how much more to read". |
| 1178 | For v1 we will later read to the end-of-line, for v2 we will read based upon |
| 1179 | the stated length. |
| 1180 | |
| 1181 | The v2 sig is 12 octets, and another 4 gets us the length, so we know how much |
| 1182 | data is needed total. For v1, where the line looks like: |
| 1183 | PROXY TCPn L3src L3dest SrcPort DestPort \r\n |
| 1184 | |
| 1185 | However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets. |
| 1186 | We seem to support that. So, if we read 14 octets then we can tell if we're |
| 1187 | v2 or v1. If we're v1, we can continue reading as normal. |
| 1188 | |
| 1189 | If we're v2, we can't slurp up the entire header. We need the length in the |
| 1190 | 15th & 16th octets, then to read everything after that. |
| 1191 | |
| 1192 | So to safely handle v1 and v2, with client-sent-first supported correctly, |
| 1193 | we have to do a minimum of 3 read calls, not 1. Eww. |
| 1194 | */ |
| 1195 | |
| 1196 | #define PROXY_INITIAL_READ 14 |
| 1197 | #define PROXY_V2_HEADER_SIZE 16 |
| 1198 | #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE |
| 1199 | # error Code bug in sizes of data to read for proxy usage |
| 1200 | #endif |
| 1201 | |
| 1202 | int get_ok = 0; |
| 1203 | int size, ret; |
| 1204 | int fd = fileno(smtp_in); |
| 1205 | const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A"; |
| 1206 | uschar * iptype; /* To display debug info */ |
| 1207 | struct timeval tv; |
| 1208 | struct timeval tvtmp; |
| 1209 | socklen_t vslen = sizeof(struct timeval); |
| 1210 | BOOL yield = FALSE; |
| 1211 | |
| 1212 | /* Save current socket timeout values */ |
| 1213 | get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen); |
| 1214 | |
| 1215 | /* Proxy Protocol host must send header within a short time |
| 1216 | (default 3 seconds) or it's considered invalid */ |
| 1217 | tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC; |
| 1218 | tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC; |
| 1219 | if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0) |
| 1220 | goto bad; |
| 1221 | |
| 1222 | do |
| 1223 | { |
| 1224 | /* The inbound host was declared to be a Proxy Protocol host, so |
| 1225 | don't do a PEEK into the data, actually slurp up enough to be |
| 1226 | "safe". Can't take it all because TLS-on-connect clients follow |
| 1227 | immediately with TLS handshake. */ |
| 1228 | ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0); |
| 1229 | } |
| 1230 | while (ret == -1 && errno == EINTR); |
| 1231 | |
| 1232 | if (ret == -1) |
| 1233 | goto proxyfail; |
| 1234 | |
| 1235 | /* For v2, handle reading the length, and then the rest. */ |
| 1236 | if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0)) |
| 1237 | { |
| 1238 | int retmore; |
| 1239 | uint8_t ver; |
| 1240 | |
| 1241 | /* First get the length fields. */ |
| 1242 | do |
| 1243 | { |
| 1244 | retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0); |
| 1245 | } while (retmore == -1 && errno == EINTR); |
| 1246 | if (retmore == -1) |
| 1247 | goto proxyfail; |
| 1248 | ret += retmore; |
| 1249 | |
| 1250 | ver = (hdr.v2.ver_cmd & 0xf0) >> 4; |
| 1251 | |
| 1252 | /* May 2014: haproxy combined the version and command into one byte to |
| 1253 | allow two full bytes for the length field in order to proxy SSL |
| 1254 | connections. SSL Proxy is not supported in this version of Exim, but |
| 1255 | must still separate values here. */ |
| 1256 | |
| 1257 | if (ver != 0x02) |
| 1258 | { |
| 1259 | DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver); |
| 1260 | goto proxyfail; |
| 1261 | } |
| 1262 | |
| 1263 | /* The v2 header will always be 16 bytes per the spec. */ |
| 1264 | size = 16 + ntohs(hdr.v2.len); |
| 1265 | DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n", |
| 1266 | size, (int)sizeof(hdr)); |
| 1267 | |
| 1268 | /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total |
| 1269 | amount that we need. Double-check that the size is not unreasonable, then |
| 1270 | get the rest. */ |
| 1271 | if (size > sizeof(hdr)) |
| 1272 | { |
| 1273 | DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n"); |
| 1274 | goto proxyfail; |
| 1275 | } |
| 1276 | |
| 1277 | do |
| 1278 | { |
| 1279 | do |
| 1280 | { |
| 1281 | retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0); |
| 1282 | } while (retmore == -1 && errno == EINTR); |
| 1283 | if (retmore == -1) |
| 1284 | goto proxyfail; |
| 1285 | ret += retmore; |
| 1286 | DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size); |
| 1287 | } while (ret < size); |
| 1288 | |
| 1289 | } /* end scope for getting rest of data for v2 */ |
| 1290 | |
| 1291 | /* At this point: if PROXYv2, we've read the exact size required for all data; |
| 1292 | if PROXYv1 then we've read "less than required for any valid line" and should |
| 1293 | read the rest". */ |
| 1294 | |
| 1295 | if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0) |
| 1296 | { |
| 1297 | uint8_t cmd = (hdr.v2.ver_cmd & 0x0f); |
| 1298 | |
| 1299 | switch (cmd) |
| 1300 | { |
| 1301 | case 0x01: /* PROXY command */ |
| 1302 | switch (hdr.v2.fam) |
| 1303 | { |
| 1304 | case 0x11: /* TCPv4 address type */ |
| 1305 | iptype = US"IPv4"; |
| 1306 | tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr; |
| 1307 | inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip)); |
| 1308 | if (!string_is_ip_address(US tmpip, NULL)) |
| 1309 | { |
| 1310 | DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype); |
| 1311 | goto proxyfail; |
| 1312 | } |
| 1313 | proxy_local_address = sender_host_address; |
| 1314 | sender_host_address = string_copy(US tmpip); |
| 1315 | tmpport = ntohs(hdr.v2.addr.ip4.src_port); |
| 1316 | proxy_local_port = sender_host_port; |
| 1317 | sender_host_port = tmpport; |
| 1318 | /* Save dest ip/port */ |
| 1319 | tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr; |
| 1320 | inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip)); |
| 1321 | if (!string_is_ip_address(US tmpip, NULL)) |
| 1322 | { |
| 1323 | DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype); |
| 1324 | goto proxyfail; |
| 1325 | } |
| 1326 | proxy_external_address = string_copy(US tmpip); |
| 1327 | tmpport = ntohs(hdr.v2.addr.ip4.dst_port); |
| 1328 | proxy_external_port = tmpport; |
| 1329 | goto done; |
| 1330 | case 0x21: /* TCPv6 address type */ |
| 1331 | iptype = US"IPv6"; |
| 1332 | memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16); |
| 1333 | inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6)); |
| 1334 | if (!string_is_ip_address(US tmpip6, NULL)) |
| 1335 | { |
| 1336 | DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype); |
| 1337 | goto proxyfail; |
| 1338 | } |
| 1339 | proxy_local_address = sender_host_address; |
| 1340 | sender_host_address = string_copy(US tmpip6); |
| 1341 | tmpport = ntohs(hdr.v2.addr.ip6.src_port); |
| 1342 | proxy_local_port = sender_host_port; |
| 1343 | sender_host_port = tmpport; |
| 1344 | /* Save dest ip/port */ |
| 1345 | memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16); |
| 1346 | inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6)); |
| 1347 | if (!string_is_ip_address(US tmpip6, NULL)) |
| 1348 | { |
| 1349 | DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype); |
| 1350 | goto proxyfail; |
| 1351 | } |
| 1352 | proxy_external_address = string_copy(US tmpip6); |
| 1353 | tmpport = ntohs(hdr.v2.addr.ip6.dst_port); |
| 1354 | proxy_external_port = tmpport; |
| 1355 | goto done; |
| 1356 | default: |
| 1357 | DEBUG(D_receive) |
| 1358 | debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n", |
| 1359 | hdr.v2.fam); |
| 1360 | goto proxyfail; |
| 1361 | } |
| 1362 | /* Unsupported protocol, keep local connection address */ |
| 1363 | break; |
| 1364 | case 0x00: /* LOCAL command */ |
| 1365 | /* Keep local connection address for LOCAL */ |
| 1366 | iptype = US"local"; |
| 1367 | break; |
| 1368 | default: |
| 1369 | DEBUG(D_receive) |
| 1370 | debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd); |
| 1371 | goto proxyfail; |
| 1372 | } |
| 1373 | } |
| 1374 | else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0) |
| 1375 | { |
| 1376 | uschar *p; |
| 1377 | uschar *end; |
| 1378 | uschar *sp; /* Utility variables follow */ |
| 1379 | int tmp_port; |
| 1380 | int r2; |
| 1381 | char *endc; |
| 1382 | |
| 1383 | /* get the rest of the line */ |
| 1384 | r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret); |
| 1385 | if (r2 == -1) |
| 1386 | goto proxyfail; |
| 1387 | ret += r2; |
| 1388 | |
| 1389 | p = string_copy(hdr.v1.line); |
| 1390 | end = memchr(p, '\r', ret - 1); |
| 1391 | |
| 1392 | if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n') |
| 1393 | { |
| 1394 | DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n"); |
| 1395 | goto proxyfail; |
| 1396 | } |
| 1397 | *end = '\0'; /* Terminate the string */ |
| 1398 | size = end + 2 - p; /* Skip header + CRLF */ |
| 1399 | DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n"); |
| 1400 | DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size); |
| 1401 | /* Step through the string looking for the required fields. Ensure |
| 1402 | strict adherence to required formatting, exit for any error. */ |
| 1403 | p += 5; |
| 1404 | if (!isspace(*(p++))) |
| 1405 | { |
| 1406 | DEBUG(D_receive) debug_printf("Missing space after PROXY command\n"); |
| 1407 | goto proxyfail; |
| 1408 | } |
| 1409 | if (!Ustrncmp(p, CCS"TCP4", 4)) |
| 1410 | iptype = US"IPv4"; |
| 1411 | else if (!Ustrncmp(p,CCS"TCP6", 4)) |
| 1412 | iptype = US"IPv6"; |
| 1413 | else if (!Ustrncmp(p,CCS"UNKNOWN", 7)) |
| 1414 | { |
| 1415 | iptype = US"Unknown"; |
| 1416 | goto done; |
| 1417 | } |
| 1418 | else |
| 1419 | { |
| 1420 | DEBUG(D_receive) debug_printf("Invalid TCP type\n"); |
| 1421 | goto proxyfail; |
| 1422 | } |
| 1423 | |
| 1424 | p += Ustrlen(iptype); |
| 1425 | if (!isspace(*(p++))) |
| 1426 | { |
| 1427 | DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n"); |
| 1428 | goto proxyfail; |
| 1429 | } |
| 1430 | /* Find the end of the arg */ |
| 1431 | if ((sp = Ustrchr(p, ' ')) == NULL) |
| 1432 | { |
| 1433 | DEBUG(D_receive) |
| 1434 | debug_printf("Did not find proxied src %s\n", iptype); |
| 1435 | goto proxyfail; |
| 1436 | } |
| 1437 | *sp = '\0'; |
| 1438 | if(!string_is_ip_address(p, NULL)) |
| 1439 | { |
| 1440 | DEBUG(D_receive) |
| 1441 | debug_printf("Proxied src arg is not an %s address\n", iptype); |
| 1442 | goto proxyfail; |
| 1443 | } |
| 1444 | proxy_local_address = sender_host_address; |
| 1445 | sender_host_address = p; |
| 1446 | p = sp + 1; |
| 1447 | if ((sp = Ustrchr(p, ' ')) == NULL) |
| 1448 | { |
| 1449 | DEBUG(D_receive) |
| 1450 | debug_printf("Did not find proxy dest %s\n", iptype); |
| 1451 | goto proxyfail; |
| 1452 | } |
| 1453 | *sp = '\0'; |
| 1454 | if(!string_is_ip_address(p, NULL)) |
| 1455 | { |
| 1456 | DEBUG(D_receive) |
| 1457 | debug_printf("Proxy dest arg is not an %s address\n", iptype); |
| 1458 | goto proxyfail; |
| 1459 | } |
| 1460 | proxy_external_address = p; |
| 1461 | p = sp + 1; |
| 1462 | if ((sp = Ustrchr(p, ' ')) == NULL) |
| 1463 | { |
| 1464 | DEBUG(D_receive) debug_printf("Did not find proxied src port\n"); |
| 1465 | goto proxyfail; |
| 1466 | } |
| 1467 | *sp = '\0'; |
| 1468 | tmp_port = strtol(CCS p, &endc, 10); |
| 1469 | if (*endc || tmp_port == 0) |
| 1470 | { |
| 1471 | DEBUG(D_receive) |
| 1472 | debug_printf("Proxied src port '%s' not an integer\n", p); |
| 1473 | goto proxyfail; |
| 1474 | } |
| 1475 | proxy_local_port = sender_host_port; |
| 1476 | sender_host_port = tmp_port; |
| 1477 | p = sp + 1; |
| 1478 | if ((sp = Ustrchr(p, '\0')) == NULL) |
| 1479 | { |
| 1480 | DEBUG(D_receive) debug_printf("Did not find proxy dest port\n"); |
| 1481 | goto proxyfail; |
| 1482 | } |
| 1483 | tmp_port = strtol(CCS p, &endc, 10); |
| 1484 | if (*endc || tmp_port == 0) |
| 1485 | { |
| 1486 | DEBUG(D_receive) |
| 1487 | debug_printf("Proxy dest port '%s' not an integer\n", p); |
| 1488 | goto proxyfail; |
| 1489 | } |
| 1490 | proxy_external_port = tmp_port; |
| 1491 | /* Already checked for /r /n above. Good V1 header received. */ |
| 1492 | } |
| 1493 | else |
| 1494 | { |
| 1495 | /* Wrong protocol */ |
| 1496 | DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n"); |
| 1497 | (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret); |
| 1498 | goto proxyfail; |
| 1499 | } |
| 1500 | |
| 1501 | done: |
| 1502 | DEBUG(D_receive) |
| 1503 | debug_printf("Valid %s sender from Proxy Protocol header\n", iptype); |
| 1504 | yield = proxy_session; |
| 1505 | |
| 1506 | /* Don't flush any potential buffer contents. Any input on proxyfail |
| 1507 | should cause a synchronization failure */ |
| 1508 | |
| 1509 | proxyfail: |
| 1510 | restore_socket_timeout(fd, get_ok, &tvtmp, vslen); |
| 1511 | |
| 1512 | bad: |
| 1513 | if (yield) |
| 1514 | { |
| 1515 | sender_host_name = NULL; |
| 1516 | (void) host_name_lookup(); |
| 1517 | host_build_sender_fullhost(); |
| 1518 | } |
| 1519 | else |
| 1520 | { |
| 1521 | proxy_session_failed = TRUE; |
| 1522 | DEBUG(D_receive) |
| 1523 | debug_printf("Failure to extract proxied host, only QUIT allowed\n"); |
| 1524 | } |
| 1525 | |
| 1526 | return; |
| 1527 | } |
| 1528 | #endif |
| 1529 | |
| 1530 | /************************************************* |
| 1531 | * Read one command line * |
| 1532 | *************************************************/ |
| 1533 | |
| 1534 | /* Strictly, SMTP commands coming over the net are supposed to end with CRLF. |
| 1535 | There are sites that don't do this, and in any case internal SMTP probably |
| 1536 | should check only for LF. Consequently, we check here for LF only. The line |
| 1537 | ends up with [CR]LF removed from its end. If we get an overlong line, treat as |
| 1538 | an unknown command. The command is read into the global smtp_cmd_buffer so that |
| 1539 | it is available via $smtp_command. |
| 1540 | |
| 1541 | The character reading routine sets up a timeout for each block actually read |
| 1542 | from the input (which may contain more than one command). We set up a special |
| 1543 | signal handler that closes down the session on a timeout. Control does not |
| 1544 | return when it runs. |
| 1545 | |
| 1546 | Arguments: |
| 1547 | check_sync if TRUE, check synchronization rules if global option is TRUE |
| 1548 | buffer_lim maximum to buffer in lower layer |
| 1549 | |
| 1550 | Returns: a code identifying the command (enumerated above) |
| 1551 | */ |
| 1552 | |
| 1553 | static int |
| 1554 | smtp_read_command(BOOL check_sync, unsigned buffer_lim) |
| 1555 | { |
| 1556 | int c; |
| 1557 | int ptr = 0; |
| 1558 | smtp_cmd_list *p; |
| 1559 | BOOL hadnull = FALSE; |
| 1560 | |
| 1561 | had_command_timeout = 0; |
| 1562 | os_non_restarting_signal(SIGALRM, command_timeout_handler); |
| 1563 | |
| 1564 | while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF) |
| 1565 | { |
| 1566 | if (ptr >= SMTP_CMD_BUFFER_SIZE) |
| 1567 | { |
| 1568 | os_non_restarting_signal(SIGALRM, sigalrm_handler); |
| 1569 | return OTHER_CMD; |
| 1570 | } |
| 1571 | if (c == 0) |
| 1572 | { |
| 1573 | hadnull = TRUE; |
| 1574 | c = '?'; |
| 1575 | } |
| 1576 | smtp_cmd_buffer[ptr++] = c; |
| 1577 | } |
| 1578 | |
| 1579 | receive_linecount++; /* For BSMTP errors */ |
| 1580 | os_non_restarting_signal(SIGALRM, sigalrm_handler); |
| 1581 | |
| 1582 | /* If hit end of file, return pseudo EOF command. Whether we have a |
| 1583 | part-line already read doesn't matter, since this is an error state. */ |
| 1584 | |
| 1585 | if (c == EOF) return EOF_CMD; |
| 1586 | |
| 1587 | /* Remove any CR and white space at the end of the line, and terminate the |
| 1588 | string. */ |
| 1589 | |
| 1590 | while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--; |
| 1591 | smtp_cmd_buffer[ptr] = 0; |
| 1592 | |
| 1593 | DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer); |
| 1594 | |
| 1595 | /* NULLs are not allowed in SMTP commands */ |
| 1596 | |
| 1597 | if (hadnull) return BADCHAR_CMD; |
| 1598 | |
| 1599 | /* Scan command list and return identity, having set the data pointer |
| 1600 | to the start of the actual data characters. Check for SMTP synchronization |
| 1601 | if required. */ |
| 1602 | |
| 1603 | for (p = cmd_list; p < cmd_list_end; p++) |
| 1604 | { |
| 1605 | #ifdef SUPPORT_PROXY |
| 1606 | /* Only allow QUIT command if Proxy Protocol parsing failed */ |
| 1607 | if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD) |
| 1608 | continue; |
| 1609 | #endif |
| 1610 | if ( p->len |
| 1611 | && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 |
| 1612 | && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */ |
| 1613 | || smtp_cmd_buffer[p->len] == 0 |
| 1614 | || smtp_cmd_buffer[p->len] == ' ' |
| 1615 | ) ) |
| 1616 | { |
| 1617 | if (smtp_inptr < smtp_inend && /* Outstanding input */ |
| 1618 | p->cmd < sync_cmd_limit && /* Command should sync */ |
| 1619 | check_sync && /* Local flag set */ |
| 1620 | smtp_enforce_sync && /* Global flag set */ |
| 1621 | sender_host_address != NULL && /* Not local input */ |
| 1622 | !sender_host_notsocket) /* Really is a socket */ |
| 1623 | return BADSYN_CMD; |
| 1624 | |
| 1625 | /* The variables $smtp_command and $smtp_command_argument point into the |
| 1626 | unmodified input buffer. A copy of the latter is taken for actual |
| 1627 | processing, so that it can be chopped up into separate parts if necessary, |
| 1628 | for example, when processing a MAIL command options such as SIZE that can |
| 1629 | follow the sender address. */ |
| 1630 | |
| 1631 | smtp_cmd_argument = smtp_cmd_buffer + p->len; |
| 1632 | while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++; |
| 1633 | Ustrcpy(smtp_data_buffer, smtp_cmd_argument); |
| 1634 | smtp_cmd_data = smtp_data_buffer; |
| 1635 | |
| 1636 | /* Count non-mail commands from those hosts that are controlled in this |
| 1637 | way. The default is all hosts. We don't waste effort checking the list |
| 1638 | until we get a non-mail command, but then cache the result to save checking |
| 1639 | again. If there's a DEFER while checking the host, assume it's in the list. |
| 1640 | |
| 1641 | Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the |
| 1642 | start of each incoming message by fiddling with the value in the table. */ |
| 1643 | |
| 1644 | if (!p->is_mail_cmd) |
| 1645 | { |
| 1646 | if (count_nonmail == TRUE_UNSET) count_nonmail = |
| 1647 | verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL; |
| 1648 | if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail) |
| 1649 | return TOO_MANY_NONMAIL_CMD; |
| 1650 | } |
| 1651 | |
| 1652 | /* If there is data for a command that does not expect it, generate the |
| 1653 | error here. */ |
| 1654 | |
| 1655 | return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD; |
| 1656 | } |
| 1657 | } |
| 1658 | |
| 1659 | #ifdef SUPPORT_PROXY |
| 1660 | /* Only allow QUIT command if Proxy Protocol parsing failed */ |
| 1661 | if (proxy_session && proxy_session_failed) |
| 1662 | return PROXY_FAIL_IGNORE_CMD; |
| 1663 | #endif |
| 1664 | |
| 1665 | /* Enforce synchronization for unknown commands */ |
| 1666 | |
| 1667 | if ( smtp_inptr < smtp_inend /* Outstanding input */ |
| 1668 | && check_sync /* Local flag set */ |
| 1669 | && smtp_enforce_sync /* Global flag set */ |
| 1670 | && sender_host_address /* Not local input */ |
| 1671 | && !sender_host_notsocket) /* Really is a socket */ |
| 1672 | return BADSYN_CMD; |
| 1673 | |
| 1674 | return OTHER_CMD; |
| 1675 | } |
| 1676 | |
| 1677 | |
| 1678 | |
| 1679 | /************************************************* |
| 1680 | * Forced closedown of call * |
| 1681 | *************************************************/ |
| 1682 | |
| 1683 | /* This function is called from log.c when Exim is dying because of a serious |
| 1684 | disaster, and also from some other places. If an incoming non-batched SMTP |
| 1685 | channel is open, it swallows the rest of the incoming message if in the DATA |
| 1686 | phase, sends the reply string, and gives an error to all subsequent commands |
| 1687 | except QUIT. The existence of an SMTP call is detected by the non-NULLness of |
| 1688 | smtp_in. |
| 1689 | |
| 1690 | Arguments: |
| 1691 | message SMTP reply string to send, excluding the code |
| 1692 | |
| 1693 | Returns: nothing |
| 1694 | */ |
| 1695 | |
| 1696 | void |
| 1697 | smtp_closedown(uschar *message) |
| 1698 | { |
| 1699 | if (!smtp_in || smtp_batched_input) return; |
| 1700 | receive_swallow_smtp(); |
| 1701 | smtp_printf("421 %s\r\n", FALSE, message); |
| 1702 | |
| 1703 | for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED)) |
| 1704 | { |
| 1705 | case EOF_CMD: |
| 1706 | return; |
| 1707 | |
| 1708 | case QUIT_CMD: |
| 1709 | smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname); |
| 1710 | mac_smtp_fflush(); |
| 1711 | return; |
| 1712 | |
| 1713 | case RSET_CMD: |
| 1714 | smtp_printf("250 Reset OK\r\n", FALSE); |
| 1715 | break; |
| 1716 | |
| 1717 | default: |
| 1718 | smtp_printf("421 %s\r\n", FALSE, message); |
| 1719 | break; |
| 1720 | } |
| 1721 | } |
| 1722 | |
| 1723 | |
| 1724 | |
| 1725 | |
| 1726 | /************************************************* |
| 1727 | * Set up connection info for logging * |
| 1728 | *************************************************/ |
| 1729 | |
| 1730 | /* This function is called when logging information about an SMTP connection. |
| 1731 | It sets up appropriate source information, depending on the type of connection. |
| 1732 | If sender_fullhost is NULL, we are at a very early stage of the connection; |
| 1733 | just use the IP address. |
| 1734 | |
| 1735 | Argument: none |
| 1736 | Returns: a string describing the connection |
| 1737 | */ |
| 1738 | |
| 1739 | uschar * |
| 1740 | smtp_get_connection_info(void) |
| 1741 | { |
| 1742 | const uschar * hostname = sender_fullhost |
| 1743 | ? sender_fullhost : sender_host_address; |
| 1744 | |
| 1745 | if (host_checking) |
| 1746 | return string_sprintf("SMTP connection from %s", hostname); |
| 1747 | |
| 1748 | if (sender_host_unknown || sender_host_notsocket) |
| 1749 | return string_sprintf("SMTP connection from %s", sender_ident); |
| 1750 | |
| 1751 | if (is_inetd) |
| 1752 | return string_sprintf("SMTP connection from %s (via inetd)", hostname); |
| 1753 | |
| 1754 | if (LOGGING(incoming_interface) && interface_address != NULL) |
| 1755 | return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname, |
| 1756 | interface_address, interface_port); |
| 1757 | |
| 1758 | return string_sprintf("SMTP connection from %s", hostname); |
| 1759 | } |
| 1760 | |
| 1761 | |
| 1762 | |
| 1763 | #ifdef SUPPORT_TLS |
| 1764 | /* Append TLS-related information to a log line |
| 1765 | |
| 1766 | Arguments: |
| 1767 | g String under construction: allocated string to extend, or NULL |
| 1768 | |
| 1769 | Returns: Allocated string or NULL |
| 1770 | */ |
| 1771 | static gstring * |
| 1772 | s_tlslog(gstring * g) |
| 1773 | { |
| 1774 | if (LOGGING(tls_cipher) && tls_in.cipher) |
| 1775 | g = string_append(g, 2, US" X=", tls_in.cipher); |
| 1776 | if (LOGGING(tls_certificate_verified) && tls_in.cipher) |
| 1777 | g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no"); |
| 1778 | if (LOGGING(tls_peerdn) && tls_in.peerdn) |
| 1779 | g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\""); |
| 1780 | if (LOGGING(tls_sni) && tls_in.sni) |
| 1781 | g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\""); |
| 1782 | return g; |
| 1783 | } |
| 1784 | #endif |
| 1785 | |
| 1786 | /************************************************* |
| 1787 | * Log lack of MAIL if so configured * |
| 1788 | *************************************************/ |
| 1789 | |
| 1790 | /* This function is called when an SMTP session ends. If the log selector |
| 1791 | smtp_no_mail is set, write a log line giving some details of what has happened |
| 1792 | in the SMTP session. |
| 1793 | |
| 1794 | Arguments: none |
| 1795 | Returns: nothing |
| 1796 | */ |
| 1797 | |
| 1798 | void |
| 1799 | smtp_log_no_mail(void) |
| 1800 | { |
| 1801 | int i; |
| 1802 | uschar * sep, * s; |
| 1803 | gstring * g = NULL; |
| 1804 | |
| 1805 | if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail)) |
| 1806 | return; |
| 1807 | |
| 1808 | if (sender_host_authenticated) |
| 1809 | { |
| 1810 | g = string_append(g, 2, US" A=", sender_host_authenticated); |
| 1811 | if (authenticated_id) g = string_append(g, 2, US":", authenticated_id); |
| 1812 | } |
| 1813 | |
| 1814 | #ifdef SUPPORT_TLS |
| 1815 | g = s_tlslog(g); |
| 1816 | #endif |
| 1817 | |
| 1818 | sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C="; |
| 1819 | |
| 1820 | for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++) |
| 1821 | if (smtp_connection_had[i] != SCH_NONE) |
| 1822 | { |
| 1823 | g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]); |
| 1824 | sep = US","; |
| 1825 | } |
| 1826 | |
| 1827 | for (i = 0; i < smtp_ch_index; i++) |
| 1828 | { |
| 1829 | g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]); |
| 1830 | sep = US","; |
| 1831 | } |
| 1832 | |
| 1833 | if (!(s = string_from_gstring(g))) s = US""; |
| 1834 | |
| 1835 | log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s", |
| 1836 | tcp_in_fastopen ? US"TFO " : US"", |
| 1837 | host_and_ident(FALSE), string_timesince(&smtp_connection_start), s); |
| 1838 | } |
| 1839 | |
| 1840 | |
| 1841 | /* Return list of recent smtp commands */ |
| 1842 | |
| 1843 | uschar * |
| 1844 | smtp_cmd_hist(void) |
| 1845 | { |
| 1846 | int i; |
| 1847 | gstring * list = NULL; |
| 1848 | uschar * s; |
| 1849 | |
| 1850 | for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++) |
| 1851 | if (smtp_connection_had[i] != SCH_NONE) |
| 1852 | list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]); |
| 1853 | |
| 1854 | for (i = 0; i < smtp_ch_index; i++) |
| 1855 | list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]); |
| 1856 | |
| 1857 | s = string_from_gstring(list); |
| 1858 | return s ? s : US""; |
| 1859 | } |
| 1860 | |
| 1861 | |
| 1862 | |
| 1863 | |
| 1864 | /************************************************* |
| 1865 | * Check HELO line and set sender_helo_name * |
| 1866 | *************************************************/ |
| 1867 | |
| 1868 | /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be |
| 1869 | the domain name of the sending host, or an ip literal in square brackets. The |
| 1870 | argument is placed in sender_helo_name, which is in malloc store, because it |
| 1871 | must persist over multiple incoming messages. If helo_accept_junk is set, this |
| 1872 | host is permitted to send any old junk (needed for some broken hosts). |
| 1873 | Otherwise, helo_allow_chars can be used for rogue characters in general |
| 1874 | (typically people want to let in underscores). |
| 1875 | |
| 1876 | Argument: |
| 1877 | s the data portion of the line (already past any white space) |
| 1878 | |
| 1879 | Returns: TRUE or FALSE |
| 1880 | */ |
| 1881 | |
| 1882 | static BOOL |
| 1883 | check_helo(uschar *s) |
| 1884 | { |
| 1885 | uschar *start = s; |
| 1886 | uschar *end = s + Ustrlen(s); |
| 1887 | BOOL yield = helo_accept_junk; |
| 1888 | |
| 1889 | /* Discard any previous helo name */ |
| 1890 | |
| 1891 | if (sender_helo_name) |
| 1892 | { |
| 1893 | store_free(sender_helo_name); |
| 1894 | sender_helo_name = NULL; |
| 1895 | } |
| 1896 | |
| 1897 | /* Skip tests if junk is permitted. */ |
| 1898 | |
| 1899 | if (!yield) |
| 1900 | |
| 1901 | /* Allow the new standard form for IPv6 address literals, namely, |
| 1902 | [IPv6:....], and because someone is bound to use it, allow an equivalent |
| 1903 | IPv4 form. Allow plain addresses as well. */ |
| 1904 | |
| 1905 | if (*s == '[') |
| 1906 | { |
| 1907 | if (end[-1] == ']') |
| 1908 | { |
| 1909 | end[-1] = 0; |
| 1910 | if (strncmpic(s, US"[IPv6:", 6) == 0) |
| 1911 | yield = (string_is_ip_address(s+6, NULL) == 6); |
| 1912 | else if (strncmpic(s, US"[IPv4:", 6) == 0) |
| 1913 | yield = (string_is_ip_address(s+6, NULL) == 4); |
| 1914 | else |
| 1915 | yield = (string_is_ip_address(s+1, NULL) != 0); |
| 1916 | end[-1] = ']'; |
| 1917 | } |
| 1918 | } |
| 1919 | |
| 1920 | /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars |
| 1921 | that have been configured (usually underscore - sigh). */ |
| 1922 | |
| 1923 | else if (*s) |
| 1924 | for (yield = TRUE; *s; s++) |
| 1925 | if (!isalnum(*s) && *s != '.' && *s != '-' && |
| 1926 | Ustrchr(helo_allow_chars, *s) == NULL) |
| 1927 | { |
| 1928 | yield = FALSE; |
| 1929 | break; |
| 1930 | } |
| 1931 | |
| 1932 | /* Save argument if OK */ |
| 1933 | |
| 1934 | if (yield) sender_helo_name = string_copy_malloc(start); |
| 1935 | return yield; |
| 1936 | } |
| 1937 | |
| 1938 | |
| 1939 | |
| 1940 | |
| 1941 | |
| 1942 | /************************************************* |
| 1943 | * Extract SMTP command option * |
| 1944 | *************************************************/ |
| 1945 | |
| 1946 | /* This function picks the next option setting off the end of smtp_cmd_data. It |
| 1947 | is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP |
| 1948 | things that can appear there. |
| 1949 | |
| 1950 | Arguments: |
| 1951 | name point this at the name |
| 1952 | value point this at the data string |
| 1953 | |
| 1954 | Returns: TRUE if found an option |
| 1955 | */ |
| 1956 | |
| 1957 | static BOOL |
| 1958 | extract_option(uschar **name, uschar **value) |
| 1959 | { |
| 1960 | uschar *n; |
| 1961 | uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1; |
| 1962 | while (isspace(*v)) v--; |
| 1963 | v[1] = 0; |
| 1964 | while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) |
| 1965 | { |
| 1966 | /* Take care to not stop at a space embedded in a quoted local-part */ |
| 1967 | |
| 1968 | if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1); |
| 1969 | v--; |
| 1970 | } |
| 1971 | |
| 1972 | n = v; |
| 1973 | if (*v == '=') |
| 1974 | { |
| 1975 | while(isalpha(n[-1])) n--; |
| 1976 | /* RFC says SP, but TAB seen in wild and other major MTAs accept it */ |
| 1977 | if (!isspace(n[-1])) return FALSE; |
| 1978 | n[-1] = 0; |
| 1979 | } |
| 1980 | else |
| 1981 | { |
| 1982 | n++; |
| 1983 | if (v == smtp_cmd_data) return FALSE; |
| 1984 | } |
| 1985 | *v++ = 0; |
| 1986 | *name = n; |
| 1987 | *value = v; |
| 1988 | return TRUE; |
| 1989 | } |
| 1990 | |
| 1991 | |
| 1992 | |
| 1993 | |
| 1994 | |
| 1995 | /************************************************* |
| 1996 | * Reset for new message * |
| 1997 | *************************************************/ |
| 1998 | |
| 1999 | /* This function is called whenever the SMTP session is reset from |
| 2000 | within either of the setup functions; also from the daemon loop. |
| 2001 | |
| 2002 | Argument: the stacking pool storage reset point |
| 2003 | Returns: nothing |
| 2004 | */ |
| 2005 | |
| 2006 | void |
| 2007 | smtp_reset(void *reset_point) |
| 2008 | { |
| 2009 | recipients_list = NULL; |
| 2010 | rcpt_count = rcpt_defer_count = rcpt_fail_count = |
| 2011 | raw_recipients_count = recipients_count = recipients_list_max = 0; |
| 2012 | message_linecount = 0; |
| 2013 | message_size = -1; |
| 2014 | acl_added_headers = NULL; |
| 2015 | acl_removed_headers = NULL; |
| 2016 | queue_only_policy = FALSE; |
| 2017 | rcpt_smtp_response = NULL; |
| 2018 | rcpt_smtp_response_same = TRUE; |
| 2019 | rcpt_in_progress = FALSE; |
| 2020 | deliver_freeze = FALSE; /* Can be set by ACL */ |
| 2021 | freeze_tell = freeze_tell_config; /* Can be set by ACL */ |
| 2022 | fake_response = OK; /* Can be set by ACL */ |
| 2023 | #ifdef WITH_CONTENT_SCAN |
| 2024 | no_mbox_unspool = FALSE; /* Can be set by ACL */ |
| 2025 | #endif |
| 2026 | submission_mode = FALSE; /* Can be set by ACL */ |
| 2027 | suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */ |
| 2028 | active_local_from_check = local_from_check; /* Can be set by ACL */ |
| 2029 | active_local_sender_retain = local_sender_retain; /* Can be set by ACL */ |
| 2030 | sending_ip_address = NULL; |
| 2031 | return_path = sender_address = NULL; |
| 2032 | sender_data = NULL; /* Can be set by ACL */ |
| 2033 | deliver_localpart_parent = deliver_localpart_orig = NULL; |
| 2034 | deliver_domain_parent = deliver_domain_orig = NULL; |
| 2035 | callout_address = NULL; |
| 2036 | submission_name = NULL; /* Can be set by ACL */ |
| 2037 | raw_sender = NULL; /* After SMTP rewrite, before qualifying */ |
| 2038 | sender_address_unrewritten = NULL; /* Set only after verify rewrite */ |
| 2039 | sender_verified_list = NULL; /* No senders verified */ |
| 2040 | memset(sender_address_cache, 0, sizeof(sender_address_cache)); |
| 2041 | memset(sender_domain_cache, 0, sizeof(sender_domain_cache)); |
| 2042 | |
| 2043 | authenticated_sender = NULL; |
| 2044 | #ifdef EXPERIMENTAL_BRIGHTMAIL |
| 2045 | bmi_run = 0; |
| 2046 | bmi_verdicts = NULL; |
| 2047 | #endif |
| 2048 | dnslist_domain = dnslist_matched = NULL; |
| 2049 | #ifdef SUPPORT_SPF |
| 2050 | spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL; |
| 2051 | spf_result_guessed = FALSE; |
| 2052 | #endif |
| 2053 | #ifndef DISABLE_DKIM |
| 2054 | dkim_cur_signer = dkim_signers = |
| 2055 | dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL; |
| 2056 | dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL; |
| 2057 | dkim_disable_verify = FALSE; |
| 2058 | dkim_collect_input = 0; |
| 2059 | dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL; |
| 2060 | dkim_key_length = 0; |
| 2061 | dkim_verify_signers = US"$dkim_signers"; |
| 2062 | #endif |
| 2063 | #ifdef EXPERIMENTAL_DMARC |
| 2064 | dmarc_has_been_checked = dmarc_disable_verify = dmarc_enable_forensic = FALSE; |
| 2065 | dmarc_domain_policy = dmarc_status = dmarc_status_text = |
| 2066 | dmarc_used_domain = NULL; |
| 2067 | #endif |
| 2068 | #ifdef EXPERIMENTAL_ARC |
| 2069 | arc_state = arc_state_reason = NULL; |
| 2070 | #endif |
| 2071 | dsn_ret = 0; |
| 2072 | dsn_envid = NULL; |
| 2073 | deliver_host = deliver_host_address = NULL; /* Can be set by ACL */ |
| 2074 | #ifndef DISABLE_PRDR |
| 2075 | prdr_requested = FALSE; |
| 2076 | #endif |
| 2077 | #ifdef SUPPORT_I18N |
| 2078 | message_smtputf8 = FALSE; |
| 2079 | #endif |
| 2080 | body_linecount = body_zerocount = 0; |
| 2081 | |
| 2082 | sender_rate = sender_rate_limit = sender_rate_period = NULL; |
| 2083 | ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */ |
| 2084 | /* Note that ratelimiters_conn persists across resets. */ |
| 2085 | |
| 2086 | /* Reset message ACL variables */ |
| 2087 | |
| 2088 | acl_var_m = NULL; |
| 2089 | |
| 2090 | /* The message body variables use malloc store. They may be set if this is |
| 2091 | not the first message in an SMTP session and the previous message caused them |
| 2092 | to be referenced in an ACL. */ |
| 2093 | |
| 2094 | if (message_body) |
| 2095 | { |
| 2096 | store_free(message_body); |
| 2097 | message_body = NULL; |
| 2098 | } |
| 2099 | |
| 2100 | if (message_body_end) |
| 2101 | { |
| 2102 | store_free(message_body_end); |
| 2103 | message_body_end = NULL; |
| 2104 | } |
| 2105 | |
| 2106 | /* Warning log messages are also saved in malloc store. They are saved to avoid |
| 2107 | repetition in the same message, but it seems right to repeat them for different |
| 2108 | messages. */ |
| 2109 | |
| 2110 | while (acl_warn_logged) |
| 2111 | { |
| 2112 | string_item *this = acl_warn_logged; |
| 2113 | acl_warn_logged = acl_warn_logged->next; |
| 2114 | store_free(this); |
| 2115 | } |
| 2116 | store_reset(reset_point); |
| 2117 | } |
| 2118 | |
| 2119 | |
| 2120 | |
| 2121 | |
| 2122 | |
| 2123 | /************************************************* |
| 2124 | * Initialize for incoming batched SMTP message * |
| 2125 | *************************************************/ |
| 2126 | |
| 2127 | /* This function is called from smtp_setup_msg() in the case when |
| 2128 | smtp_batched_input is true. This happens when -bS is used to pass a whole batch |
| 2129 | of messages in one file with SMTP commands between them. All errors must be |
| 2130 | reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are |
| 2131 | relevant. After an error on a sender, or an invalid recipient, the remainder |
| 2132 | of the message is skipped. The value of received_protocol is already set. |
| 2133 | |
| 2134 | Argument: none |
| 2135 | Returns: > 0 message successfully started (reached DATA) |
| 2136 | = 0 QUIT read or end of file reached |
| 2137 | < 0 should not occur |
| 2138 | */ |
| 2139 | |
| 2140 | static int |
| 2141 | smtp_setup_batch_msg(void) |
| 2142 | { |
| 2143 | int done = 0; |
| 2144 | void *reset_point = store_get(0); |
| 2145 | |
| 2146 | /* Save the line count at the start of each transaction - single commands |
| 2147 | like HELO and RSET count as whole transactions. */ |
| 2148 | |
| 2149 | bsmtp_transaction_linecount = receive_linecount; |
| 2150 | |
| 2151 | if ((receive_feof)()) return 0; /* Treat EOF as QUIT */ |
| 2152 | |
| 2153 | cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg"); |
| 2154 | smtp_reset(reset_point); /* Reset for start of message */ |
| 2155 | |
| 2156 | /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE |
| 2157 | value. The values are 2 larger than the required yield of the function. */ |
| 2158 | |
| 2159 | while (done <= 0) |
| 2160 | { |
| 2161 | uschar *errmess; |
| 2162 | uschar *recipient = NULL; |
| 2163 | int start, end, sender_domain, recipient_domain; |
| 2164 | |
| 2165 | switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED)) |
| 2166 | { |
| 2167 | /* The HELO/EHLO commands set sender_address_helo if they have |
| 2168 | valid data; otherwise they are ignored, except that they do |
| 2169 | a reset of the state. */ |
| 2170 | |
| 2171 | case HELO_CMD: |
| 2172 | case EHLO_CMD: |
| 2173 | |
| 2174 | check_helo(smtp_cmd_data); |
| 2175 | /* Fall through */ |
| 2176 | |
| 2177 | case RSET_CMD: |
| 2178 | cancel_cutthrough_connection(TRUE, US"RSET received"); |
| 2179 | smtp_reset(reset_point); |
| 2180 | bsmtp_transaction_linecount = receive_linecount; |
| 2181 | break; |
| 2182 | |
| 2183 | |
| 2184 | /* The MAIL FROM command requires an address as an operand. All we |
| 2185 | do here is to parse it for syntactic correctness. The form "<>" is |
| 2186 | a special case which converts into an empty string. The start/end |
| 2187 | pointers in the original are not used further for this address, as |
| 2188 | it is the canonical extracted address which is all that is kept. */ |
| 2189 | |
| 2190 | case MAIL_CMD: |
| 2191 | smtp_mailcmd_count++; /* Count for no-mail log */ |
| 2192 | if (sender_address != NULL) |
| 2193 | /* The function moan_smtp_batch() does not return. */ |
| 2194 | moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given"); |
| 2195 | |
| 2196 | if (smtp_cmd_data[0] == 0) |
| 2197 | /* The function moan_smtp_batch() does not return. */ |
| 2198 | moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand"); |
| 2199 | |
| 2200 | /* Reset to start of message */ |
| 2201 | |
| 2202 | cancel_cutthrough_connection(TRUE, US"MAIL received"); |
| 2203 | smtp_reset(reset_point); |
| 2204 | |
| 2205 | /* Apply SMTP rewrite */ |
| 2206 | |
| 2207 | raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)? |
| 2208 | rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE, |
| 2209 | US"", global_rewrite_rules) : smtp_cmd_data; |
| 2210 | |
| 2211 | /* Extract the address; the TRUE flag allows <> as valid */ |
| 2212 | |
| 2213 | raw_sender = |
| 2214 | parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain, |
| 2215 | TRUE); |
| 2216 | |
| 2217 | if (!raw_sender) |
| 2218 | /* The function moan_smtp_batch() does not return. */ |
| 2219 | moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess); |
| 2220 | |
| 2221 | sender_address = string_copy(raw_sender); |
| 2222 | |
| 2223 | /* Qualify unqualified sender addresses if permitted to do so. */ |
| 2224 | |
| 2225 | if ( !sender_domain |
| 2226 | && sender_address[0] != 0 && sender_address[0] != '@') |
| 2227 | if (allow_unqualified_sender) |
| 2228 | { |
| 2229 | sender_address = rewrite_address_qualify(sender_address, FALSE); |
| 2230 | DEBUG(D_receive) debug_printf("unqualified address %s accepted " |
| 2231 | "and rewritten\n", raw_sender); |
| 2232 | } |
| 2233 | /* The function moan_smtp_batch() does not return. */ |
| 2234 | else |
| 2235 | moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain " |
| 2236 | "a domain"); |
| 2237 | break; |
| 2238 | |
| 2239 | |
| 2240 | /* The RCPT TO command requires an address as an operand. All we do |
| 2241 | here is to parse it for syntactic correctness. There may be any number |
| 2242 | of RCPT TO commands, specifying multiple senders. We build them all into |
| 2243 | a data structure that is in argc/argv format. The start/end values |
| 2244 | given by parse_extract_address are not used, as we keep only the |
| 2245 | extracted address. */ |
| 2246 | |
| 2247 | case RCPT_CMD: |
| 2248 | if (!sender_address) |
| 2249 | /* The function moan_smtp_batch() does not return. */ |
| 2250 | moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given"); |
| 2251 | |
| 2252 | if (smtp_cmd_data[0] == 0) |
| 2253 | /* The function moan_smtp_batch() does not return. */ |
| 2254 | moan_smtp_batch(smtp_cmd_buffer, |
| 2255 | "501 RCPT TO must have an address operand"); |
| 2256 | |
| 2257 | /* Check maximum number allowed */ |
| 2258 | |
| 2259 | if (recipients_max > 0 && recipients_count + 1 > recipients_max) |
| 2260 | /* The function moan_smtp_batch() does not return. */ |
| 2261 | moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients", |
| 2262 | recipients_max_reject? "552": "452"); |
| 2263 | |
| 2264 | /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a |
| 2265 | recipient address */ |
| 2266 | |
| 2267 | recipient = rewrite_existflags & rewrite_smtp |
| 2268 | ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"", |
| 2269 | global_rewrite_rules) |
| 2270 | : smtp_cmd_data; |
| 2271 | |
| 2272 | recipient = parse_extract_address(recipient, &errmess, &start, &end, |
| 2273 | &recipient_domain, FALSE); |
| 2274 | |
| 2275 | if (!recipient) |
| 2276 | /* The function moan_smtp_batch() does not return. */ |
| 2277 | moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess); |
| 2278 | |
| 2279 | /* If the recipient address is unqualified, qualify it if permitted. Then |
| 2280 | add it to the list of recipients. */ |
| 2281 | |
| 2282 | if (!recipient_domain) |
| 2283 | if (allow_unqualified_recipient) |
| 2284 | { |
| 2285 | DEBUG(D_receive) debug_printf("unqualified address %s accepted\n", |
| 2286 | recipient); |
| 2287 | recipient = rewrite_address_qualify(recipient, TRUE); |
| 2288 | } |
| 2289 | /* The function moan_smtp_batch() does not return. */ |
| 2290 | else |
| 2291 | moan_smtp_batch(smtp_cmd_buffer, |
| 2292 | "501 recipient address must contain a domain"); |
| 2293 | |
| 2294 | receive_add_recipient(recipient, -1); |
| 2295 | break; |
| 2296 | |
| 2297 | |
| 2298 | /* The DATA command is legal only if it follows successful MAIL FROM |
| 2299 | and RCPT TO commands. This function is complete when a valid DATA |
| 2300 | command is encountered. */ |
| 2301 | |
| 2302 | case DATA_CMD: |
| 2303 | if (!sender_address || recipients_count <= 0) |
| 2304 | /* The function moan_smtp_batch() does not return. */ |
| 2305 | if (!sender_address) |
| 2306 | moan_smtp_batch(smtp_cmd_buffer, |
| 2307 | "503 MAIL FROM:<sender> command must precede DATA"); |
| 2308 | else |
| 2309 | moan_smtp_batch(smtp_cmd_buffer, |
| 2310 | "503 RCPT TO:<recipient> must precede DATA"); |
| 2311 | else |
| 2312 | { |
| 2313 | done = 3; /* DATA successfully achieved */ |
| 2314 | message_ended = END_NOTENDED; /* Indicate in middle of message */ |
| 2315 | } |
| 2316 | break; |
| 2317 | |
| 2318 | |
| 2319 | /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */ |
| 2320 | |
| 2321 | case VRFY_CMD: |
| 2322 | case EXPN_CMD: |
| 2323 | case HELP_CMD: |
| 2324 | case NOOP_CMD: |
| 2325 | case ETRN_CMD: |
| 2326 | bsmtp_transaction_linecount = receive_linecount; |
| 2327 | break; |
| 2328 | |
| 2329 | |
| 2330 | case EOF_CMD: |
| 2331 | case QUIT_CMD: |
| 2332 | done = 2; |
| 2333 | break; |
| 2334 | |
| 2335 | |
| 2336 | case BADARG_CMD: |
| 2337 | /* The function moan_smtp_batch() does not return. */ |
| 2338 | moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data"); |
| 2339 | break; |
| 2340 | |
| 2341 | |
| 2342 | case BADCHAR_CMD: |
| 2343 | /* The function moan_smtp_batch() does not return. */ |
| 2344 | moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command"); |
| 2345 | break; |
| 2346 | |
| 2347 | |
| 2348 | default: |
| 2349 | /* The function moan_smtp_batch() does not return. */ |
| 2350 | moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized"); |
| 2351 | break; |
| 2352 | } |
| 2353 | } |
| 2354 | |
| 2355 | return done - 2; /* Convert yield values */ |
| 2356 | } |
| 2357 | |
| 2358 | |
| 2359 | |
| 2360 | |
| 2361 | static BOOL |
| 2362 | smtp_log_tls_fail(uschar * errstr) |
| 2363 | { |
| 2364 | uschar * conn_info = smtp_get_connection_info(); |
| 2365 | |
| 2366 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5; |
| 2367 | /* I'd like to get separated H= here, but too hard for now */ |
| 2368 | |
| 2369 | log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr); |
| 2370 | return FALSE; |
| 2371 | } |
| 2372 | |
| 2373 | |
| 2374 | |
| 2375 | |
| 2376 | #ifdef TCP_FASTOPEN |
| 2377 | static void |
| 2378 | tfo_in_check(void) |
| 2379 | { |
| 2380 | # ifdef TCP_INFO |
| 2381 | struct tcp_info tinfo; |
| 2382 | socklen_t len = sizeof(tinfo); |
| 2383 | |
| 2384 | if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0 |
| 2385 | && tinfo.tcpi_state == TCP_SYN_RECV |
| 2386 | ) |
| 2387 | { |
| 2388 | DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n"); |
| 2389 | tcp_in_fastopen = TRUE; |
| 2390 | } |
| 2391 | # endif |
| 2392 | } |
| 2393 | #endif |
| 2394 | |
| 2395 | |
| 2396 | /************************************************* |
| 2397 | * Start an SMTP session * |
| 2398 | *************************************************/ |
| 2399 | |
| 2400 | /* This function is called at the start of an SMTP session. Thereafter, |
| 2401 | smtp_setup_msg() is called to initiate each separate message. This |
| 2402 | function does host-specific testing, and outputs the banner line. |
| 2403 | |
| 2404 | Arguments: none |
| 2405 | Returns: FALSE if the session can not continue; something has |
| 2406 | gone wrong, or the connection to the host is blocked |
| 2407 | */ |
| 2408 | |
| 2409 | BOOL |
| 2410 | smtp_start_session(void) |
| 2411 | { |
| 2412 | int esclen; |
| 2413 | uschar *user_msg, *log_msg; |
| 2414 | uschar *code, *esc; |
| 2415 | uschar *p, *s; |
| 2416 | gstring * ss; |
| 2417 | |
| 2418 | gettimeofday(&smtp_connection_start, NULL); |
| 2419 | for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++) |
| 2420 | smtp_connection_had[smtp_ch_index] = SCH_NONE; |
| 2421 | smtp_ch_index = 0; |
| 2422 | |
| 2423 | /* Default values for certain variables */ |
| 2424 | |
| 2425 | helo_seen = esmtp = helo_accept_junk = FALSE; |
| 2426 | smtp_mailcmd_count = 0; |
| 2427 | count_nonmail = TRUE_UNSET; |
| 2428 | synprot_error_count = unknown_command_count = nonmail_command_count = 0; |
| 2429 | smtp_delay_mail = smtp_rlm_base; |
| 2430 | auth_advertised = FALSE; |
| 2431 | smtp_in_pipelining_advertised = FALSE; |
| 2432 | pipelining_enable = TRUE; |
| 2433 | sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING; |
| 2434 | smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */ |
| 2435 | |
| 2436 | /* If receiving by -bs from a trusted user, or testing with -bh, we allow |
| 2437 | authentication settings from -oMaa to remain in force. */ |
| 2438 | |
| 2439 | if (!host_checking && !sender_host_notsocket) |
| 2440 | sender_host_auth_pubname = sender_host_authenticated = NULL; |
| 2441 | authenticated_by = NULL; |
| 2442 | |
| 2443 | #ifdef SUPPORT_TLS |
| 2444 | tls_in.cipher = tls_in.peerdn = NULL; |
| 2445 | tls_in.ourcert = tls_in.peercert = NULL; |
| 2446 | tls_in.sni = NULL; |
| 2447 | tls_in.ocsp = OCSP_NOT_REQ; |
| 2448 | tls_advertised = FALSE; |
| 2449 | # ifdef EXPERIMENTAL_REQUIRETLS |
| 2450 | requiretls_advertised = FALSE; |
| 2451 | # endif |
| 2452 | #endif |
| 2453 | dsn_advertised = FALSE; |
| 2454 | #ifdef SUPPORT_I18N |
| 2455 | smtputf8_advertised = FALSE; |
| 2456 | #endif |
| 2457 | |
| 2458 | /* Reset ACL connection variables */ |
| 2459 | |
| 2460 | acl_var_c = NULL; |
| 2461 | |
| 2462 | /* Allow for trailing 0 in the command and data buffers. */ |
| 2463 | |
| 2464 | if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2))) |
| 2465 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, |
| 2466 | "malloc() failed for SMTP command buffer"); |
| 2467 | |
| 2468 | smtp_cmd_buffer[0] = 0; |
| 2469 | smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1; |
| 2470 | |
| 2471 | /* For batched input, the protocol setting can be overridden from the |
| 2472 | command line by a trusted caller. */ |
| 2473 | |
| 2474 | if (smtp_batched_input) |
| 2475 | { |
| 2476 | if (!received_protocol) received_protocol = US"local-bsmtp"; |
| 2477 | } |
| 2478 | |
| 2479 | /* For non-batched SMTP input, the protocol setting is forced here. It will be |
| 2480 | reset later if any of EHLO/AUTH/STARTTLS are received. */ |
| 2481 | |
| 2482 | else |
| 2483 | received_protocol = |
| 2484 | (sender_host_address ? protocols : protocols_local) [pnormal]; |
| 2485 | |
| 2486 | /* Set up the buffer for inputting using direct read() calls, and arrange to |
| 2487 | call the local functions instead of the standard C ones. Place a NUL at the |
| 2488 | end of the buffer to safety-stop C-string reads from it. */ |
| 2489 | |
| 2490 | if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE))) |
| 2491 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer"); |
| 2492 | smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0'; |
| 2493 | |
| 2494 | receive_getc = smtp_getc; |
| 2495 | receive_getbuf = smtp_getbuf; |
| 2496 | receive_get_cache = smtp_get_cache; |
| 2497 | receive_ungetc = smtp_ungetc; |
| 2498 | receive_feof = smtp_feof; |
| 2499 | receive_ferror = smtp_ferror; |
| 2500 | receive_smtp_buffered = smtp_buffered; |
| 2501 | smtp_inptr = smtp_inend = smtp_inbuffer; |
| 2502 | smtp_had_eof = smtp_had_error = 0; |
| 2503 | |
| 2504 | /* Set up the message size limit; this may be host-specific */ |
| 2505 | |
| 2506 | thismessage_size_limit = expand_string_integer(message_size_limit, TRUE); |
| 2507 | if (expand_string_message) |
| 2508 | { |
| 2509 | if (thismessage_size_limit == -1) |
| 2510 | log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: " |
| 2511 | "%s", expand_string_message); |
| 2512 | else |
| 2513 | log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: " |
| 2514 | "%s", expand_string_message); |
| 2515 | smtp_closedown(US"Temporary local problem - please try later"); |
| 2516 | return FALSE; |
| 2517 | } |
| 2518 | |
| 2519 | /* When a message is input locally via the -bs or -bS options, sender_host_ |
| 2520 | unknown is set unless -oMa was used to force an IP address, in which case it |
| 2521 | is checked like a real remote connection. When -bs is used from inetd, this |
| 2522 | flag is not set, causing the sending host to be checked. The code that deals |
| 2523 | with IP source routing (if configured) is never required for -bs or -bS and |
| 2524 | the flag sender_host_notsocket is used to suppress it. |
| 2525 | |
| 2526 | If smtp_accept_max and smtp_accept_reserve are set, keep some connections in |
| 2527 | reserve for certain hosts and/or networks. */ |
| 2528 | |
| 2529 | if (!sender_host_unknown) |
| 2530 | { |
| 2531 | int rc; |
| 2532 | BOOL reserved_host = FALSE; |
| 2533 | |
| 2534 | /* Look up IP options (source routing info) on the socket if this is not an |
| 2535 | -oMa "host", and if any are found, log them and drop the connection. |
| 2536 | |
| 2537 | Linux (and others now, see below) is different to everyone else, so there |
| 2538 | has to be some conditional compilation here. Versions of Linux before 2.1.15 |
| 2539 | used a structure whose name was "options". Somebody finally realized that |
| 2540 | this name was silly, and it got changed to "ip_options". I use the |
| 2541 | newer name here, but there is a fudge in the script that sets up os.h |
| 2542 | to define a macro in older Linux systems. |
| 2543 | |
| 2544 | Sigh. Linux is a fast-moving target. Another generation of Linux uses |
| 2545 | glibc 2, which has chosen ip_opts for the structure name. This is now |
| 2546 | really a glibc thing rather than a Linux thing, so the condition name |
| 2547 | has been changed to reflect this. It is relevant also to GNU/Hurd. |
| 2548 | |
| 2549 | Mac OS 10.x (Darwin) is like the later glibc versions, but without the |
| 2550 | setting of the __GLIBC__ macro, so we can't detect it automatically. There's |
| 2551 | a special macro defined in the os.h file. |
| 2552 | |
| 2553 | Some DGUX versions on older hardware appear not to support IP options at |
| 2554 | all, so there is now a general macro which can be set to cut out this |
| 2555 | support altogether. |
| 2556 | |
| 2557 | How to do this properly in IPv6 is not yet known. */ |
| 2558 | |
| 2559 | #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS) |
| 2560 | |
| 2561 | #ifdef GLIBC_IP_OPTIONS |
| 2562 | #if (!defined __GLIBC__) || (__GLIBC__ < 2) |
| 2563 | #define OPTSTYLE 1 |
| 2564 | #else |
| 2565 | #define OPTSTYLE 2 |
| 2566 | #endif |
| 2567 | #elif defined DARWIN_IP_OPTIONS |
| 2568 | #define OPTSTYLE 2 |
| 2569 | #else |
| 2570 | #define OPTSTYLE 3 |
| 2571 | #endif |
| 2572 | |
| 2573 | if (!host_checking && !sender_host_notsocket) |
| 2574 | { |
| 2575 | #if OPTSTYLE == 1 |
| 2576 | EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN; |
| 2577 | struct ip_options *ipopt = store_get(optlen); |
| 2578 | #elif OPTSTYLE == 2 |
| 2579 | struct ip_opts ipoptblock; |
| 2580 | struct ip_opts *ipopt = &ipoptblock; |
| 2581 | EXIM_SOCKLEN_T optlen = sizeof(ipoptblock); |
| 2582 | #else |
| 2583 | struct ipoption ipoptblock; |
| 2584 | struct ipoption *ipopt = &ipoptblock; |
| 2585 | EXIM_SOCKLEN_T optlen = sizeof(ipoptblock); |
| 2586 | #endif |
| 2587 | |
| 2588 | /* Occasional genuine failures of getsockopt() have been seen - for |
| 2589 | example, "reset by peer". Therefore, just log and give up on this |
| 2590 | call, unless the error is ENOPROTOOPT. This error is given by systems |
| 2591 | that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time |
| 2592 | of writing. So for that error, carry on - we just can't do an IP options |
| 2593 | check. */ |
| 2594 | |
| 2595 | DEBUG(D_receive) debug_printf("checking for IP options\n"); |
| 2596 | |
| 2597 | if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt), |
| 2598 | &optlen) < 0) |
| 2599 | { |
| 2600 | if (errno != ENOPROTOOPT) |
| 2601 | { |
| 2602 | log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s", |
| 2603 | host_and_ident(FALSE), strerror(errno)); |
| 2604 | smtp_printf("451 SMTP service not available\r\n", FALSE); |
| 2605 | return FALSE; |
| 2606 | } |
| 2607 | } |
| 2608 | |
| 2609 | /* Deal with any IP options that are set. On the systems I have looked at, |
| 2610 | the value of MAX_IPOPTLEN has been 40, meaning that there should never be |
| 2611 | more logging data than will fit in big_buffer. Nevertheless, after somebody |
| 2612 | questioned this code, I've added in some paranoid checking. */ |
| 2613 | |
| 2614 | else if (optlen > 0) |
| 2615 | { |
| 2616 | uschar *p = big_buffer; |
| 2617 | uschar *pend = big_buffer + big_buffer_size; |
| 2618 | uschar *opt, *adptr; |
| 2619 | int optcount; |
| 2620 | struct in_addr addr; |
| 2621 | |
| 2622 | #if OPTSTYLE == 1 |
| 2623 | uschar *optstart = US (ipopt->__data); |
| 2624 | #elif OPTSTYLE == 2 |
| 2625 | uschar *optstart = US (ipopt->ip_opts); |
| 2626 | #else |
| 2627 | uschar *optstart = US (ipopt->ipopt_list); |
| 2628 | #endif |
| 2629 | |
| 2630 | DEBUG(D_receive) debug_printf("IP options exist\n"); |
| 2631 | |
| 2632 | Ustrcpy(p, "IP options on incoming call:"); |
| 2633 | p += Ustrlen(p); |
| 2634 | |
| 2635 | for (opt = optstart; opt != NULL && |
| 2636 | opt < US (ipopt) + optlen;) |
| 2637 | { |
| 2638 | switch (*opt) |
| 2639 | { |
| 2640 | case IPOPT_EOL: |
| 2641 | opt = NULL; |
| 2642 | break; |
| 2643 | |
| 2644 | case IPOPT_NOP: |
| 2645 | opt++; |
| 2646 | break; |
| 2647 | |
| 2648 | case IPOPT_SSRR: |
| 2649 | case IPOPT_LSRR: |
| 2650 | if (!string_format(p, pend-p, " %s [@%s", |
| 2651 | (*opt == IPOPT_SSRR)? "SSRR" : "LSRR", |
| 2652 | #if OPTSTYLE == 1 |
| 2653 | inet_ntoa(*((struct in_addr *)(&(ipopt->faddr)))))) |
| 2654 | #elif OPTSTYLE == 2 |
| 2655 | inet_ntoa(ipopt->ip_dst))) |
| 2656 | #else |
| 2657 | inet_ntoa(ipopt->ipopt_dst))) |
| 2658 | #endif |
| 2659 | { |
| 2660 | opt = NULL; |
| 2661 | break; |
| 2662 | } |
| 2663 | |
| 2664 | p += Ustrlen(p); |
| 2665 | optcount = (opt[1] - 3) / sizeof(struct in_addr); |
| 2666 | adptr = opt + 3; |
| 2667 | while (optcount-- > 0) |
| 2668 | { |
| 2669 | memcpy(&addr, adptr, sizeof(addr)); |
| 2670 | if (!string_format(p, pend - p - 1, "%s%s", |
| 2671 | (optcount == 0)? ":" : "@", inet_ntoa(addr))) |
| 2672 | { |
| 2673 | opt = NULL; |
| 2674 | break; |
| 2675 | } |
| 2676 | p += Ustrlen(p); |
| 2677 | adptr += sizeof(struct in_addr); |
| 2678 | } |
| 2679 | *p++ = ']'; |
| 2680 | opt += opt[1]; |
| 2681 | break; |
| 2682 | |
| 2683 | default: |
| 2684 | { |
| 2685 | int i; |
| 2686 | if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; } |
| 2687 | Ustrcat(p, "[ "); |
| 2688 | p += 2; |
| 2689 | for (i = 0; i < opt[1]; i++) |
| 2690 | p += sprintf(CS p, "%2.2x ", opt[i]); |
| 2691 | *p++ = ']'; |
| 2692 | } |
| 2693 | opt += opt[1]; |
| 2694 | break; |
| 2695 | } |
| 2696 | } |
| 2697 | |
| 2698 | *p = 0; |
| 2699 | log_write(0, LOG_MAIN, "%s", big_buffer); |
| 2700 | |
| 2701 | /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */ |
| 2702 | |
| 2703 | log_write(0, LOG_MAIN|LOG_REJECT, |
| 2704 | "connection from %s refused (IP options)", host_and_ident(FALSE)); |
| 2705 | |
| 2706 | smtp_printf("554 SMTP service not available\r\n", FALSE); |
| 2707 | return FALSE; |
| 2708 | } |
| 2709 | |
| 2710 | /* Length of options = 0 => there are no options */ |
| 2711 | |
| 2712 | else DEBUG(D_receive) debug_printf("no IP options found\n"); |
| 2713 | } |
| 2714 | #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */ |
| 2715 | |
| 2716 | /* Set keep-alive in socket options. The option is on by default. This |
| 2717 | setting is an attempt to get rid of some hanging connections that stick in |
| 2718 | read() when the remote end (usually a dialup) goes away. */ |
| 2719 | |
| 2720 | if (smtp_accept_keepalive && !sender_host_notsocket) |
| 2721 | ip_keepalive(fileno(smtp_out), sender_host_address, FALSE); |
| 2722 | |
| 2723 | /* If the current host matches host_lookup, set the name by doing a |
| 2724 | reverse lookup. On failure, sender_host_name will be NULL and |
| 2725 | host_lookup_failed will be TRUE. This may or may not be serious - optional |
| 2726 | checks later. */ |
| 2727 | |
| 2728 | if (verify_check_host(&host_lookup) == OK) |
| 2729 | { |
| 2730 | (void)host_name_lookup(); |
| 2731 | host_build_sender_fullhost(); |
| 2732 | } |
| 2733 | |
| 2734 | /* Delay this until we have the full name, if it is looked up. */ |
| 2735 | |
| 2736 | set_process_info("handling incoming connection from %s", |
| 2737 | host_and_ident(FALSE)); |
| 2738 | |
| 2739 | /* Expand smtp_receive_timeout, if needed */ |
| 2740 | |
| 2741 | if (smtp_receive_timeout_s) |
| 2742 | { |
| 2743 | uschar * exp; |
| 2744 | if ( !(exp = expand_string(smtp_receive_timeout_s)) |
| 2745 | || !(*exp) |
| 2746 | || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0 |
| 2747 | ) |
| 2748 | log_write(0, LOG_MAIN|LOG_PANIC, |
| 2749 | "bad value for smtp_receive_timeout: '%s'", exp ? exp : US""); |
| 2750 | } |
| 2751 | |
| 2752 | /* Test for explicit connection rejection */ |
| 2753 | |
| 2754 | if (verify_check_host(&host_reject_connection) == OK) |
| 2755 | { |
| 2756 | log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection " |
| 2757 | "from %s (host_reject_connection)", host_and_ident(FALSE)); |
| 2758 | smtp_printf("554 SMTP service not available\r\n", FALSE); |
| 2759 | return FALSE; |
| 2760 | } |
| 2761 | |
| 2762 | /* Test with TCP Wrappers if so configured. There is a problem in that |
| 2763 | hosts_ctl() returns 0 (deny) under a number of system failure circumstances, |
| 2764 | such as disks dying. In these cases, it is desirable to reject with a 4xx |
| 2765 | error instead of a 5xx error. There isn't a "right" way to detect such |
| 2766 | problems. The following kludge is used: errno is zeroed before calling |
| 2767 | hosts_ctl(). If the result is "reject", a 5xx error is given only if the |
| 2768 | value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does |
| 2769 | not exist). */ |
| 2770 | |
| 2771 | #ifdef USE_TCP_WRAPPERS |
| 2772 | errno = 0; |
| 2773 | if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name))) |
| 2774 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" " |
| 2775 | "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name), |
| 2776 | expand_string_message); |
| 2777 | |
| 2778 | if (!hosts_ctl(tcp_wrappers_name, |
| 2779 | sender_host_name ? CS sender_host_name : STRING_UNKNOWN, |
| 2780 | sender_host_address ? CS sender_host_address : STRING_UNKNOWN, |
| 2781 | sender_ident ? CS sender_ident : STRING_UNKNOWN)) |
| 2782 | { |
| 2783 | if (errno == 0 || errno == ENOENT) |
| 2784 | { |
| 2785 | HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n"); |
| 2786 | log_write(L_connection_reject, |
| 2787 | LOG_MAIN|LOG_REJECT, "refused connection from %s " |
| 2788 | "(tcp wrappers)", host_and_ident(FALSE)); |
| 2789 | smtp_printf("554 SMTP service not available\r\n", FALSE); |
| 2790 | } |
| 2791 | else |
| 2792 | { |
| 2793 | int save_errno = errno; |
| 2794 | HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected " |
| 2795 | "errno value %d\n", save_errno); |
| 2796 | log_write(L_connection_reject, |
| 2797 | LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s " |
| 2798 | "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno); |
| 2799 | smtp_printf("451 Temporary local problem - please try later\r\n", FALSE); |
| 2800 | } |
| 2801 | return FALSE; |
| 2802 | } |
| 2803 | #endif |
| 2804 | |
| 2805 | /* Check for reserved slots. The value of smtp_accept_count has already been |
| 2806 | incremented to include this process. */ |
| 2807 | |
| 2808 | if (smtp_accept_max > 0 && |
| 2809 | smtp_accept_count > smtp_accept_max - smtp_accept_reserve) |
| 2810 | { |
| 2811 | if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK) |
| 2812 | { |
| 2813 | log_write(L_connection_reject, |
| 2814 | LOG_MAIN, "temporarily refused connection from %s: not in " |
| 2815 | "reserve list: connected=%d max=%d reserve=%d%s", |
| 2816 | host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max, |
| 2817 | smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : ""); |
| 2818 | smtp_printf("421 %s: Too many concurrent SMTP connections; " |
| 2819 | "please try again later\r\n", FALSE, smtp_active_hostname); |
| 2820 | return FALSE; |
| 2821 | } |
| 2822 | reserved_host = TRUE; |
| 2823 | } |
| 2824 | |
| 2825 | /* If a load level above which only messages from reserved hosts are |
| 2826 | accepted is set, check the load. For incoming calls via the daemon, the |
| 2827 | check is done in the superior process if there are no reserved hosts, to |
| 2828 | save a fork. In all cases, the load average will already be available |
| 2829 | in a global variable at this point. */ |
| 2830 | |
| 2831 | if (smtp_load_reserve >= 0 && |
| 2832 | load_average > smtp_load_reserve && |
| 2833 | !reserved_host && |
| 2834 | verify_check_host(&smtp_reserve_hosts) != OK) |
| 2835 | { |
| 2836 | log_write(L_connection_reject, |
| 2837 | LOG_MAIN, "temporarily refused connection from %s: not in " |
| 2838 | "reserve list and load average = %.2f", host_and_ident(FALSE), |
| 2839 | (double)load_average/1000.0); |
| 2840 | smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE, |
| 2841 | smtp_active_hostname); |
| 2842 | return FALSE; |
| 2843 | } |
| 2844 | |
| 2845 | /* Determine whether unqualified senders or recipients are permitted |
| 2846 | for this host. Unfortunately, we have to do this every time, in order to |
| 2847 | set the flags so that they can be inspected when considering qualifying |
| 2848 | addresses in the headers. For a site that permits no qualification, this |
| 2849 | won't take long, however. */ |
| 2850 | |
| 2851 | allow_unqualified_sender = |
| 2852 | verify_check_host(&sender_unqualified_hosts) == OK; |
| 2853 | |
| 2854 | allow_unqualified_recipient = |
| 2855 | verify_check_host(&recipient_unqualified_hosts) == OK; |
| 2856 | |
| 2857 | /* Determine whether HELO/EHLO is required for this host. The requirement |
| 2858 | can be hard or soft. */ |
| 2859 | |
| 2860 | helo_required = verify_check_host(&helo_verify_hosts) == OK; |
| 2861 | if (!helo_required) |
| 2862 | helo_verify = verify_check_host(&helo_try_verify_hosts) == OK; |
| 2863 | |
| 2864 | /* Determine whether this hosts is permitted to send syntactic junk |
| 2865 | after a HELO or EHLO command. */ |
| 2866 | |
| 2867 | helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK; |
| 2868 | } |
| 2869 | |
| 2870 | /* For batch SMTP input we are now done. */ |
| 2871 | |
| 2872 | if (smtp_batched_input) return TRUE; |
| 2873 | |
| 2874 | /* If valid Proxy Protocol source is connecting, set up session. |
| 2875 | * Failure will not allow any SMTP function other than QUIT. */ |
| 2876 | |
| 2877 | #ifdef SUPPORT_PROXY |
| 2878 | proxy_session = FALSE; |
| 2879 | proxy_session_failed = FALSE; |
| 2880 | if (check_proxy_protocol_host()) |
| 2881 | setup_proxy_protocol_host(); |
| 2882 | #endif |
| 2883 | |
| 2884 | /* Start up TLS if tls_on_connect is set. This is for supporting the legacy |
| 2885 | smtps port for use with older style SSL MTAs. */ |
| 2886 | |
| 2887 | #ifdef SUPPORT_TLS |
| 2888 | if (tls_in.on_connect) |
| 2889 | { |
| 2890 | if (tls_server_start(tls_require_ciphers, &user_msg) != OK) |
| 2891 | return smtp_log_tls_fail(user_msg); |
| 2892 | cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE; |
| 2893 | } |
| 2894 | #endif |
| 2895 | |
| 2896 | /* Run the connect ACL if it exists */ |
| 2897 | |
| 2898 | user_msg = NULL; |
| 2899 | if (acl_smtp_connect) |
| 2900 | { |
| 2901 | int rc; |
| 2902 | if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg, |
| 2903 | &log_msg)) != OK) |
| 2904 | { |
| 2905 | (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg); |
| 2906 | return FALSE; |
| 2907 | } |
| 2908 | } |
| 2909 | |
| 2910 | /* Output the initial message for a two-way SMTP connection. It may contain |
| 2911 | newlines, which then cause a multi-line response to be given. */ |
| 2912 | |
| 2913 | code = US"220"; /* Default status code */ |
| 2914 | esc = US""; /* Default extended status code */ |
| 2915 | esclen = 0; /* Length of esc */ |
| 2916 | |
| 2917 | if (!user_msg) |
| 2918 | { |
| 2919 | if (!(s = expand_string(smtp_banner))) |
| 2920 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) " |
| 2921 | "failed: %s", smtp_banner, expand_string_message); |
| 2922 | } |
| 2923 | else |
| 2924 | { |
| 2925 | int codelen = 3; |
| 2926 | s = user_msg; |
| 2927 | smtp_message_code(&code, &codelen, &s, NULL, TRUE); |
| 2928 | if (codelen > 4) |
| 2929 | { |
| 2930 | esc = code + 4; |
| 2931 | esclen = codelen - 4; |
| 2932 | } |
| 2933 | } |
| 2934 | |
| 2935 | /* Remove any terminating newlines; might as well remove trailing space too */ |
| 2936 | |
| 2937 | p = s + Ustrlen(s); |
| 2938 | while (p > s && isspace(p[-1])) p--; |
| 2939 | *p = 0; |
| 2940 | |
| 2941 | /* It seems that CC:Mail is braindead, and assumes that the greeting message |
| 2942 | is all contained in a single IP packet. The original code wrote out the |
| 2943 | greeting using several calls to fprint/fputc, and on busy servers this could |
| 2944 | cause it to be split over more than one packet - which caused CC:Mail to fall |
| 2945 | over when it got the second part of the greeting after sending its first |
| 2946 | command. Sigh. To try to avoid this, build the complete greeting message |
| 2947 | first, and output it in one fell swoop. This gives a better chance of it |
| 2948 | ending up as a single packet. */ |
| 2949 | |
| 2950 | ss = string_get(256); |
| 2951 | |
| 2952 | p = s; |
| 2953 | do /* At least once, in case we have an empty string */ |
| 2954 | { |
| 2955 | int len; |
| 2956 | uschar *linebreak = Ustrchr(p, '\n'); |
| 2957 | ss = string_catn(ss, code, 3); |
| 2958 | if (!linebreak) |
| 2959 | { |
| 2960 | len = Ustrlen(p); |
| 2961 | ss = string_catn(ss, US" ", 1); |
| 2962 | } |
| 2963 | else |
| 2964 | { |
| 2965 | len = linebreak - p; |
| 2966 | ss = string_catn(ss, US"-", 1); |
| 2967 | } |
| 2968 | ss = string_catn(ss, esc, esclen); |
| 2969 | ss = string_catn(ss, p, len); |
| 2970 | ss = string_catn(ss, US"\r\n", 2); |
| 2971 | p += len; |
| 2972 | if (linebreak) p++; |
| 2973 | } |
| 2974 | while (*p); |
| 2975 | |
| 2976 | /* Before we write the banner, check that there is no input pending, unless |
| 2977 | this synchronisation check is disabled. */ |
| 2978 | |
| 2979 | if (!check_sync()) |
| 2980 | { |
| 2981 | unsigned n = smtp_inend - smtp_inptr; |
| 2982 | if (n > 32) n = 32; |
| 2983 | |
| 2984 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol " |
| 2985 | "synchronization error (input sent without waiting for greeting): " |
| 2986 | "rejected connection from %s input=\"%s\"", host_and_ident(TRUE), |
| 2987 | string_printing(string_copyn(smtp_inptr, n))); |
| 2988 | smtp_printf("554 SMTP synchronization error\r\n", FALSE); |
| 2989 | return FALSE; |
| 2990 | } |
| 2991 | |
| 2992 | /* Now output the banner */ |
| 2993 | |
| 2994 | smtp_printf("%s", FALSE, string_from_gstring(ss)); |
| 2995 | |
| 2996 | /* Attempt to see if we sent the banner before the last ACK of the 3-way |
| 2997 | handshake arrived. If so we must have managed a TFO. */ |
| 2998 | |
| 2999 | #ifdef TCP_FASTOPEN |
| 3000 | tfo_in_check(); |
| 3001 | #endif |
| 3002 | |
| 3003 | return TRUE; |
| 3004 | } |
| 3005 | |
| 3006 | |
| 3007 | |
| 3008 | |
| 3009 | |
| 3010 | /************************************************* |
| 3011 | * Handle SMTP syntax and protocol errors * |
| 3012 | *************************************************/ |
| 3013 | |
| 3014 | /* Write to the log for SMTP syntax errors in incoming commands, if configured |
| 3015 | to do so. Then transmit the error response. The return value depends on the |
| 3016 | number of syntax and protocol errors in this SMTP session. |
| 3017 | |
| 3018 | Arguments: |
| 3019 | type error type, given as a log flag bit |
| 3020 | code response code; <= 0 means don't send a response |
| 3021 | data data to reflect in the response (can be NULL) |
| 3022 | errmess the error message |
| 3023 | |
| 3024 | Returns: -1 limit of syntax/protocol errors NOT exceeded |
| 3025 | +1 limit of syntax/protocol errors IS exceeded |
| 3026 | |
| 3027 | These values fit in with the values of the "done" variable in the main |
| 3028 | processing loop in smtp_setup_msg(). */ |
| 3029 | |
| 3030 | static int |
| 3031 | synprot_error(int type, int code, uschar *data, uschar *errmess) |
| 3032 | { |
| 3033 | int yield = -1; |
| 3034 | |
| 3035 | log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s", |
| 3036 | (type == L_smtp_syntax_error)? "syntax" : "protocol", |
| 3037 | string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess); |
| 3038 | |
| 3039 | if (++synprot_error_count > smtp_max_synprot_errors) |
| 3040 | { |
| 3041 | yield = 1; |
| 3042 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " |
| 3043 | "syntax or protocol errors (last command was \"%s\")", |
| 3044 | host_and_ident(FALSE), string_printing(smtp_cmd_buffer)); |
| 3045 | } |
| 3046 | |
| 3047 | if (code > 0) |
| 3048 | { |
| 3049 | smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ', |
| 3050 | data ? data : US"", data ? US": " : US"", errmess); |
| 3051 | if (yield == 1) |
| 3052 | smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code); |
| 3053 | } |
| 3054 | |
| 3055 | return yield; |
| 3056 | } |
| 3057 | |
| 3058 | |
| 3059 | |
| 3060 | |
| 3061 | /************************************************* |
| 3062 | * Send SMTP response, possibly multiline * |
| 3063 | *************************************************/ |
| 3064 | |
| 3065 | /* There are, it seems, broken clients out there that cannot handle multiline |
| 3066 | responses. If no_multiline_responses is TRUE (it can be set from an ACL), we |
| 3067 | output nothing for non-final calls, and only the first line for anything else. |
| 3068 | |
| 3069 | Arguments: |
| 3070 | code SMTP code, may involve extended status codes |
| 3071 | codelen length of smtp code; if > 4 there's an ESC |
| 3072 | final FALSE if the last line isn't the final line |
| 3073 | msg message text, possibly containing newlines |
| 3074 | |
| 3075 | Returns: nothing |
| 3076 | */ |
| 3077 | |
| 3078 | void |
| 3079 | smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg) |
| 3080 | { |
| 3081 | int esclen = 0; |
| 3082 | uschar *esc = US""; |
| 3083 | |
| 3084 | if (!final && no_multiline_responses) return; |
| 3085 | |
| 3086 | if (codelen > 4) |
| 3087 | { |
| 3088 | esc = code + 4; |
| 3089 | esclen = codelen - 4; |
| 3090 | } |
| 3091 | |
| 3092 | /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs |
| 3093 | have had the same. Note: this code is also present in smtp_printf(). It would |
| 3094 | be tidier to have it only in one place, but when it was added, it was easier to |
| 3095 | do it that way, so as not to have to mess with the code for the RCPT command, |
| 3096 | which sometimes uses smtp_printf() and sometimes smtp_respond(). */ |
| 3097 | |
| 3098 | if (rcpt_in_progress) |
| 3099 | { |
| 3100 | if (rcpt_smtp_response == NULL) |
| 3101 | rcpt_smtp_response = string_copy(msg); |
| 3102 | else if (rcpt_smtp_response_same && |
| 3103 | Ustrcmp(rcpt_smtp_response, msg) != 0) |
| 3104 | rcpt_smtp_response_same = FALSE; |
| 3105 | rcpt_in_progress = FALSE; |
| 3106 | } |
| 3107 | |
| 3108 | /* Now output the message, splitting it up into multiple lines if necessary. |
| 3109 | We only handle pipelining these responses as far as nonfinal/final groups, |
| 3110 | not the whole MAIL/RCPT/DATA response set. */ |
| 3111 | |
| 3112 | for (;;) |
| 3113 | { |
| 3114 | uschar *nl = Ustrchr(msg, '\n'); |
| 3115 | if (nl == NULL) |
| 3116 | { |
| 3117 | smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg); |
| 3118 | return; |
| 3119 | } |
| 3120 | else if (nl[1] == 0 || no_multiline_responses) |
| 3121 | { |
| 3122 | smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc, |
| 3123 | (int)(nl - msg), msg); |
| 3124 | return; |
| 3125 | } |
| 3126 | else |
| 3127 | { |
| 3128 | smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg); |
| 3129 | msg = nl + 1; |
| 3130 | while (isspace(*msg)) msg++; |
| 3131 | } |
| 3132 | } |
| 3133 | } |
| 3134 | |
| 3135 | |
| 3136 | |
| 3137 | |
| 3138 | /************************************************* |
| 3139 | * Parse user SMTP message * |
| 3140 | *************************************************/ |
| 3141 | |
| 3142 | /* This function allows for user messages overriding the response code details |
| 3143 | by providing a suitable response code string at the start of the message |
| 3144 | user_msg. Check the message for starting with a response code and optionally an |
| 3145 | extended status code. If found, check that the first digit is valid, and if so, |
| 3146 | change the code pointer and length to use the replacement. An invalid code |
| 3147 | causes a panic log; in this case, if the log messages is the same as the user |
| 3148 | message, we must also adjust the value of the log message to show the code that |
| 3149 | is actually going to be used (the original one). |
| 3150 | |
| 3151 | This function is global because it is called from receive.c as well as within |
| 3152 | this module. |
| 3153 | |
| 3154 | Note that the code length returned includes the terminating whitespace |
| 3155 | character, which is always included in the regex match. |
| 3156 | |
| 3157 | Arguments: |
| 3158 | code SMTP code, may involve extended status codes |
| 3159 | codelen length of smtp code; if > 4 there's an ESC |
| 3160 | msg message text |
| 3161 | log_msg optional log message, to be adjusted with the new SMTP code |
| 3162 | check_valid if true, verify the response code |
| 3163 | |
| 3164 | Returns: nothing |
| 3165 | */ |
| 3166 | |
| 3167 | void |
| 3168 | smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg, |
| 3169 | BOOL check_valid) |
| 3170 | { |
| 3171 | int n; |
| 3172 | int ovector[3]; |
| 3173 | |
| 3174 | if (!msg || !*msg) return; |
| 3175 | |
| 3176 | if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0, |
| 3177 | PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return; |
| 3178 | |
| 3179 | if (check_valid && (*msg)[0] != (*code)[0]) |
| 3180 | { |
| 3181 | log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with " |
| 3182 | "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg); |
| 3183 | if (log_msg != NULL && *log_msg == *msg) |
| 3184 | *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]); |
| 3185 | } |
| 3186 | else |
| 3187 | { |
| 3188 | *code = *msg; |
| 3189 | *codelen = ovector[1]; /* Includes final space */ |
| 3190 | } |
| 3191 | *msg += ovector[1]; /* Chop the code off the message */ |
| 3192 | return; |
| 3193 | } |
| 3194 | |
| 3195 | |
| 3196 | |
| 3197 | |
| 3198 | /************************************************* |
| 3199 | * Handle an ACL failure * |
| 3200 | *************************************************/ |
| 3201 | |
| 3202 | /* This function is called when acl_check() fails. As well as calls from within |
| 3203 | this module, it is called from receive.c for an ACL after DATA. It sorts out |
| 3204 | logging the incident, and sends the error response. A message containing |
| 3205 | newlines is turned into a multiline SMTP response, but for logging, only the |
| 3206 | first line is used. |
| 3207 | |
| 3208 | There's a table of default permanent failure response codes to use in |
| 3209 | globals.c, along with the table of names. VFRY is special. Despite RFC1123 it |
| 3210 | defaults disabled in Exim. However, discussion in connection with RFC 821bis |
| 3211 | (aka RFC 2821) has concluded that the response should be 252 in the disabled |
| 3212 | state, because there are broken clients that try VRFY before RCPT. A 5xx |
| 3213 | response should be given only when the address is positively known to be |
| 3214 | undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides |
| 3215 | no explicit code, but if there is one we let it know best. |
| 3216 | Also, for ETRN, 458 is given on refusal, and for AUTH, 503. |
| 3217 | |
| 3218 | From Exim 4.63, it is possible to override the response code details by |
| 3219 | providing a suitable response code string at the start of the message provided |
| 3220 | in user_msg. The code's first digit is checked for validity. |
| 3221 | |
| 3222 | Arguments: |
| 3223 | where where the ACL was called from |
| 3224 | rc the failure code |
| 3225 | user_msg a message that can be included in an SMTP response |
| 3226 | log_msg a message for logging |
| 3227 | |
| 3228 | Returns: 0 in most cases |
| 3229 | 2 if the failure code was FAIL_DROP, in which case the |
| 3230 | SMTP connection should be dropped (this value fits with the |
| 3231 | "done" variable in smtp_setup_msg() below) |
| 3232 | */ |
| 3233 | |
| 3234 | int |
| 3235 | smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg) |
| 3236 | { |
| 3237 | BOOL drop = rc == FAIL_DROP; |
| 3238 | int codelen = 3; |
| 3239 | uschar *smtp_code; |
| 3240 | uschar *lognl; |
| 3241 | uschar *sender_info = US""; |
| 3242 | uschar *what = |
| 3243 | #ifdef WITH_CONTENT_SCAN |
| 3244 | where == ACL_WHERE_MIME ? US"during MIME ACL checks" : |
| 3245 | #endif |
| 3246 | where == ACL_WHERE_PREDATA ? US"DATA" : |
| 3247 | where == ACL_WHERE_DATA ? US"after DATA" : |
| 3248 | #ifndef DISABLE_PRDR |
| 3249 | where == ACL_WHERE_PRDR ? US"after DATA PRDR" : |
| 3250 | #endif |
| 3251 | smtp_cmd_data ? |
| 3252 | string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) : |
| 3253 | string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]); |
| 3254 | |
| 3255 | if (drop) rc = FAIL; |
| 3256 | |
| 3257 | /* Set the default SMTP code, and allow a user message to change it. */ |
| 3258 | |
| 3259 | smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451"; |
| 3260 | smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg, |
| 3261 | where != ACL_WHERE_VRFY); |
| 3262 | |
| 3263 | /* We used to have sender_address here; however, there was a bug that was not |
| 3264 | updating sender_address after a rewrite during a verify. When this bug was |
| 3265 | fixed, sender_address at this point became the rewritten address. I'm not sure |
| 3266 | this is what should be logged, so I've changed to logging the unrewritten |
| 3267 | address to retain backward compatibility. */ |
| 3268 | |
| 3269 | #ifndef WITH_CONTENT_SCAN |
| 3270 | if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA) |
| 3271 | #else |
| 3272 | if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME) |
| 3273 | #endif |
| 3274 | { |
| 3275 | sender_info = string_sprintf("F=<%s>%s%s%s%s ", |
| 3276 | sender_address_unrewritten ? sender_address_unrewritten : sender_address, |
| 3277 | sender_host_authenticated ? US" A=" : US"", |
| 3278 | sender_host_authenticated ? sender_host_authenticated : US"", |
| 3279 | sender_host_authenticated && authenticated_id ? US":" : US"", |
| 3280 | sender_host_authenticated && authenticated_id ? authenticated_id : US"" |
| 3281 | ); |
| 3282 | } |
| 3283 | |
| 3284 | /* If there's been a sender verification failure with a specific message, and |
| 3285 | we have not sent a response about it yet, do so now, as a preliminary line for |
| 3286 | failures, but not defers. However, always log it for defer, and log it for fail |
| 3287 | unless the sender_verify_fail log selector has been turned off. */ |
| 3288 | |
| 3289 | if (sender_verified_failed && |
| 3290 | !testflag(sender_verified_failed, af_sverify_told)) |
| 3291 | { |
| 3292 | BOOL save_rcpt_in_progress = rcpt_in_progress; |
| 3293 | rcpt_in_progress = FALSE; /* So as not to treat these as the error */ |
| 3294 | |
| 3295 | setflag(sender_verified_failed, af_sverify_told); |
| 3296 | |
| 3297 | if (rc != FAIL || LOGGING(sender_verify_fail)) |
| 3298 | log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s", |
| 3299 | host_and_ident(TRUE), |
| 3300 | ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail", |
| 3301 | sender_verified_failed->address, |
| 3302 | (sender_verified_failed->message == NULL)? US"" : |
| 3303 | string_sprintf(": %s", sender_verified_failed->message)); |
| 3304 | |
| 3305 | if (rc == FAIL && sender_verified_failed->user_message) |
| 3306 | smtp_respond(smtp_code, codelen, FALSE, string_sprintf( |
| 3307 | testflag(sender_verified_failed, af_verify_pmfail)? |
| 3308 | "Postmaster verification failed while checking <%s>\n%s\n" |
| 3309 | "Several RFCs state that you are required to have a postmaster\n" |
| 3310 | "mailbox for each mail domain. This host does not accept mail\n" |
| 3311 | "from domains whose servers reject the postmaster address." |
| 3312 | : |
| 3313 | testflag(sender_verified_failed, af_verify_nsfail)? |
| 3314 | "Callback setup failed while verifying <%s>\n%s\n" |
| 3315 | "The initial connection, or a HELO or MAIL FROM:<> command was\n" |
| 3316 | "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n" |
| 3317 | "RFC requirements, and stops you from receiving standard bounce\n" |
| 3318 | "messages. This host does not accept mail from domains whose servers\n" |
| 3319 | "refuse bounces." |
| 3320 | : |
| 3321 | "Verification failed for <%s>\n%s", |
| 3322 | sender_verified_failed->address, |
| 3323 | sender_verified_failed->user_message)); |
| 3324 | |
| 3325 | rcpt_in_progress = save_rcpt_in_progress; |
| 3326 | } |
| 3327 | |
| 3328 | /* Sort out text for logging */ |
| 3329 | |
| 3330 | log_msg = log_msg ? string_sprintf(": %s", log_msg) : US""; |
| 3331 | if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0; |
| 3332 | |
| 3333 | /* Send permanent failure response to the command, but the code used isn't |
| 3334 | always a 5xx one - see comments at the start of this function. If the original |
| 3335 | rc was FAIL_DROP we drop the connection and yield 2. */ |
| 3336 | |
| 3337 | if (rc == FAIL) |
| 3338 | smtp_respond(smtp_code, codelen, TRUE, |
| 3339 | user_msg ? user_msg : US"Administrative prohibition"); |
| 3340 | |
| 3341 | /* Send temporary failure response to the command. Don't give any details, |
| 3342 | unless acl_temp_details is set. This is TRUE for a callout defer, a "defer" |
| 3343 | verb, and for a header verify when smtp_return_error_details is set. |
| 3344 | |
| 3345 | This conditional logic is all somewhat of a mess because of the odd |
| 3346 | interactions between temp_details and return_error_details. One day it should |
| 3347 | be re-implemented in a tidier fashion. */ |
| 3348 | |
| 3349 | else |
| 3350 | if (acl_temp_details && user_msg) |
| 3351 | { |
| 3352 | if ( smtp_return_error_details |
| 3353 | && sender_verified_failed |
| 3354 | && sender_verified_failed->message |
| 3355 | ) |
| 3356 | smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message); |
| 3357 | |
| 3358 | smtp_respond(smtp_code, codelen, TRUE, user_msg); |
| 3359 | } |
| 3360 | else |
| 3361 | smtp_respond(smtp_code, codelen, TRUE, |
| 3362 | US"Temporary local problem - please try later"); |
| 3363 | |
| 3364 | /* Log the incident to the logs that are specified by log_reject_target |
| 3365 | (default main, reject). This can be empty to suppress logging of rejections. If |
| 3366 | the connection is not forcibly to be dropped, return 0. Otherwise, log why it |
| 3367 | is closing if required and return 2. */ |
| 3368 | |
| 3369 | if (log_reject_target != 0) |
| 3370 | { |
| 3371 | #ifdef SUPPORT_TLS |
| 3372 | gstring * g = s_tlslog(NULL); |
| 3373 | uschar * tls = string_from_gstring(g); |
| 3374 | if (!tls) tls = US""; |
| 3375 | #else |
| 3376 | uschar * tls = US""; |
| 3377 | #endif |
| 3378 | log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0, |
| 3379 | log_reject_target, "%s%s%s %s%srejected %s%s", |
| 3380 | LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"", |
| 3381 | host_and_ident(TRUE), |
| 3382 | tls, |
| 3383 | sender_info, |
| 3384 | rc == FAIL ? US"" : US"temporarily ", |
| 3385 | what, log_msg); |
| 3386 | } |
| 3387 | |
| 3388 | if (!drop) return 0; |
| 3389 | |
| 3390 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL", |
| 3391 | smtp_get_connection_info()); |
| 3392 | |
| 3393 | /* Run the not-quit ACL, but without any custom messages. This should not be a |
| 3394 | problem, because we get here only if some other ACL has issued "drop", and |
| 3395 | in that case, *its* custom messages will have been used above. */ |
| 3396 | |
| 3397 | smtp_notquit_exit(US"acl-drop", NULL, NULL); |
| 3398 | return 2; |
| 3399 | } |
| 3400 | |
| 3401 | |
| 3402 | |
| 3403 | |
| 3404 | /************************************************* |
| 3405 | * Handle SMTP exit when QUIT is not given * |
| 3406 | *************************************************/ |
| 3407 | |
| 3408 | /* This function provides a logging/statistics hook for when an SMTP connection |
| 3409 | is dropped on the floor or the other end goes away. It's a global function |
| 3410 | because it's called from receive.c as well as this module. As well as running |
| 3411 | the NOTQUIT ACL, if there is one, this function also outputs a final SMTP |
| 3412 | response, either with a custom message from the ACL, or using a default. There |
| 3413 | is one case, however, when no message is output - after "drop". In that case, |
| 3414 | the ACL that obeyed "drop" has already supplied the custom message, and NULL is |
| 3415 | passed to this function. |
| 3416 | |
| 3417 | In case things go wrong while processing this function, causing an error that |
| 3418 | may re-enter this function, there is a recursion check. |
| 3419 | |
| 3420 | Arguments: |
| 3421 | reason What $smtp_notquit_reason will be set to in the ACL; |
| 3422 | if NULL, the ACL is not run |
| 3423 | code The error code to return as part of the response |
| 3424 | defaultrespond The default message if there's no user_msg |
| 3425 | |
| 3426 | Returns: Nothing |
| 3427 | */ |
| 3428 | |
| 3429 | void |
| 3430 | smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...) |
| 3431 | { |
| 3432 | int rc; |
| 3433 | uschar *user_msg = NULL; |
| 3434 | uschar *log_msg = NULL; |
| 3435 | |
| 3436 | /* Check for recursive acll */ |
| 3437 | |
| 3438 | if (smtp_exit_function_called) |
| 3439 | { |
| 3440 | log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)", |
| 3441 | reason); |
| 3442 | return; |
| 3443 | } |
| 3444 | smtp_exit_function_called = TRUE; |
| 3445 | |
| 3446 | /* Call the not-QUIT ACL, if there is one, unless no reason is given. */ |
| 3447 | |
| 3448 | if (acl_smtp_notquit && reason) |
| 3449 | { |
| 3450 | smtp_notquit_reason = reason; |
| 3451 | if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg, |
| 3452 | &log_msg)) == ERROR) |
| 3453 | log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s", |
| 3454 | log_msg); |
| 3455 | } |
| 3456 | |
| 3457 | /* Write an SMTP response if we are expected to give one. As the default |
| 3458 | responses are all internal, they should always fit in the buffer, but code a |
| 3459 | warning, just in case. Note that string_vformat() still leaves a complete |
| 3460 | string, even if it is incomplete. */ |
| 3461 | |
| 3462 | if (code && defaultrespond) |
| 3463 | { |
| 3464 | if (user_msg) |
| 3465 | smtp_respond(code, 3, TRUE, user_msg); |
| 3466 | else |
| 3467 | { |
| 3468 | uschar buffer[128]; |
| 3469 | va_list ap; |
| 3470 | va_start(ap, defaultrespond); |
| 3471 | if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap)) |
| 3472 | log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()"); |
| 3473 | smtp_printf("%s %s\r\n", FALSE, code, buffer); |
| 3474 | va_end(ap); |
| 3475 | } |
| 3476 | mac_smtp_fflush(); |
| 3477 | } |
| 3478 | } |
| 3479 | |
| 3480 | |
| 3481 | |
| 3482 | |
| 3483 | /************************************************* |
| 3484 | * Verify HELO argument * |
| 3485 | *************************************************/ |
| 3486 | |
| 3487 | /* This function is called if helo_verify_hosts or helo_try_verify_hosts is |
| 3488 | matched. It is also called from ACL processing if verify = helo is used and |
| 3489 | verification was not previously tried (i.e. helo_try_verify_hosts was not |
| 3490 | matched). The result of its processing is to set helo_verified and |
| 3491 | helo_verify_failed. These variables should both be FALSE for this function to |
| 3492 | be called. |
| 3493 | |
| 3494 | Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow |
| 3495 | for IPv6 ::ffff: literals. |
| 3496 | |
| 3497 | Argument: none |
| 3498 | Returns: TRUE if testing was completed; |
| 3499 | FALSE on a temporary failure |
| 3500 | */ |
| 3501 | |
| 3502 | BOOL |
| 3503 | smtp_verify_helo(void) |
| 3504 | { |
| 3505 | BOOL yield = TRUE; |
| 3506 | |
| 3507 | HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n", |
| 3508 | sender_helo_name); |
| 3509 | |
| 3510 | if (sender_helo_name == NULL) |
| 3511 | { |
| 3512 | HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n"); |
| 3513 | } |
| 3514 | |
| 3515 | /* Deal with the case of -bs without an IP address */ |
| 3516 | |
| 3517 | else if (sender_host_address == NULL) |
| 3518 | { |
| 3519 | HDEBUG(D_receive) debug_printf("no client IP address: assume success\n"); |
| 3520 | helo_verified = TRUE; |
| 3521 | } |
| 3522 | |
| 3523 | /* Deal with the more common case when there is a sending IP address */ |
| 3524 | |
| 3525 | else if (sender_helo_name[0] == '[') |
| 3526 | { |
| 3527 | helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address, |
| 3528 | Ustrlen(sender_host_address)) == 0; |
| 3529 | |
| 3530 | #if HAVE_IPV6 |
| 3531 | if (!helo_verified) |
| 3532 | { |
| 3533 | if (strncmpic(sender_host_address, US"::ffff:", 7) == 0) |
| 3534 | helo_verified = Ustrncmp(sender_helo_name + 1, |
| 3535 | sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0; |
| 3536 | } |
| 3537 | #endif |
| 3538 | |
| 3539 | HDEBUG(D_receive) |
| 3540 | { if (helo_verified) debug_printf("matched host address\n"); } |
| 3541 | } |
| 3542 | |
| 3543 | /* Do a reverse lookup if one hasn't already given a positive or negative |
| 3544 | response. If that fails, or the name doesn't match, try checking with a forward |
| 3545 | lookup. */ |
| 3546 | |
| 3547 | else |
| 3548 | { |
| 3549 | if (sender_host_name == NULL && !host_lookup_failed) |
| 3550 | yield = host_name_lookup() != DEFER; |
| 3551 | |
| 3552 | /* If a host name is known, check it and all its aliases. */ |
| 3553 | |
| 3554 | if (sender_host_name) |
| 3555 | if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0)) |
| 3556 | { |
| 3557 | sender_helo_dnssec = sender_host_dnssec; |
| 3558 | HDEBUG(D_receive) debug_printf("matched host name\n"); |
| 3559 | } |
| 3560 | else |
| 3561 | { |
| 3562 | uschar **aliases = sender_host_aliases; |
| 3563 | while (*aliases) |
| 3564 | if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0)) |
| 3565 | { |
| 3566 | sender_helo_dnssec = sender_host_dnssec; |
| 3567 | break; |
| 3568 | } |
| 3569 | |
| 3570 | HDEBUG(D_receive) if (helo_verified) |
| 3571 | debug_printf("matched alias %s\n", *(--aliases)); |
| 3572 | } |
| 3573 | |
| 3574 | /* Final attempt: try a forward lookup of the helo name */ |
| 3575 | |
| 3576 | if (!helo_verified) |
| 3577 | { |
| 3578 | int rc; |
| 3579 | host_item h; |
| 3580 | dnssec_domains d; |
| 3581 | host_item *hh; |
| 3582 | |
| 3583 | h.name = sender_helo_name; |
| 3584 | h.address = NULL; |
| 3585 | h.mx = MX_NONE; |
| 3586 | h.next = NULL; |
| 3587 | d.request = US"*"; |
| 3588 | d.require = US""; |
| 3589 | |
| 3590 | HDEBUG(D_receive) debug_printf("getting IP address for %s\n", |
| 3591 | sender_helo_name); |
| 3592 | rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA, |
| 3593 | NULL, NULL, NULL, &d, NULL, NULL); |
| 3594 | if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL) |
| 3595 | for (hh = &h; hh; hh = hh->next) |
| 3596 | if (Ustrcmp(hh->address, sender_host_address) == 0) |
| 3597 | { |
| 3598 | helo_verified = TRUE; |
| 3599 | if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE; |
| 3600 | HDEBUG(D_receive) |
| 3601 | { |
| 3602 | debug_printf("IP address for %s matches calling address\n" |
| 3603 | "Forward DNS security status: %sverified\n", |
| 3604 | sender_helo_name, sender_helo_dnssec ? "" : "un"); |
| 3605 | } |
| 3606 | break; |
| 3607 | } |
| 3608 | } |
| 3609 | } |
| 3610 | |
| 3611 | if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */ |
| 3612 | return yield; |
| 3613 | } |
| 3614 | |
| 3615 | |
| 3616 | |
| 3617 | |
| 3618 | /************************************************* |
| 3619 | * Send user response message * |
| 3620 | *************************************************/ |
| 3621 | |
| 3622 | /* This function is passed a default response code and a user message. It calls |
| 3623 | smtp_message_code() to check and possibly modify the response code, and then |
| 3624 | calls smtp_respond() to transmit the response. I put this into a function |
| 3625 | just to avoid a lot of repetition. |
| 3626 | |
| 3627 | Arguments: |
| 3628 | code the response code |
| 3629 | user_msg the user message |
| 3630 | |
| 3631 | Returns: nothing |
| 3632 | */ |
| 3633 | |
| 3634 | static void |
| 3635 | smtp_user_msg(uschar *code, uschar *user_msg) |
| 3636 | { |
| 3637 | int len = 3; |
| 3638 | smtp_message_code(&code, &len, &user_msg, NULL, TRUE); |
| 3639 | smtp_respond(code, len, TRUE, user_msg); |
| 3640 | } |
| 3641 | |
| 3642 | |
| 3643 | |
| 3644 | static int |
| 3645 | smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss) |
| 3646 | { |
| 3647 | const uschar *set_id = NULL; |
| 3648 | int rc, i; |
| 3649 | |
| 3650 | /* Run the checking code, passing the remainder of the command line as |
| 3651 | data. Initials the $auth<n> variables as empty. Initialize $0 empty and set |
| 3652 | it as the only set numerical variable. The authenticator may set $auth<n> |
| 3653 | and also set other numeric variables. The $auth<n> variables are preferred |
| 3654 | nowadays; the numerical variables remain for backwards compatibility. |
| 3655 | |
| 3656 | Afterwards, have a go at expanding the set_id string, even if |
| 3657 | authentication failed - for bad passwords it can be useful to log the |
| 3658 | userid. On success, require set_id to expand and exist, and put it in |
| 3659 | authenticated_id. Save this in permanent store, as the working store gets |
| 3660 | reset at HELO, RSET, etc. */ |
| 3661 | |
| 3662 | for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; |
| 3663 | expand_nmax = 0; |
| 3664 | expand_nlength[0] = 0; /* $0 contains nothing */ |
| 3665 | |
| 3666 | rc = (au->info->servercode)(au, smtp_cmd_data); |
| 3667 | if (au->set_id) set_id = expand_string(au->set_id); |
| 3668 | expand_nmax = -1; /* Reset numeric variables */ |
| 3669 | for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */ |
| 3670 | |
| 3671 | /* The value of authenticated_id is stored in the spool file and printed in |
| 3672 | log lines. It must not contain binary zeros or newline characters. In |
| 3673 | normal use, it never will, but when playing around or testing, this error |
| 3674 | can (did) happen. To guard against this, ensure that the id contains only |
| 3675 | printing characters. */ |
| 3676 | |
| 3677 | if (set_id) set_id = string_printing(set_id); |
| 3678 | |
| 3679 | /* For the non-OK cases, set up additional logging data if set_id |
| 3680 | is not empty. */ |
| 3681 | |
| 3682 | if (rc != OK) |
| 3683 | set_id = set_id && *set_id |
| 3684 | ? string_sprintf(" (set_id=%s)", set_id) : US""; |
| 3685 | |
| 3686 | /* Switch on the result */ |
| 3687 | |
| 3688 | switch(rc) |
| 3689 | { |
| 3690 | case OK: |
| 3691 | if (!au->set_id || set_id) /* Complete success */ |
| 3692 | { |
| 3693 | if (set_id) authenticated_id = string_copy_malloc(set_id); |
| 3694 | sender_host_authenticated = au->name; |
| 3695 | sender_host_auth_pubname = au->public_name; |
| 3696 | authentication_failed = FALSE; |
| 3697 | authenticated_fail_id = NULL; /* Impossible to already be set? */ |
| 3698 | |
| 3699 | received_protocol = |
| 3700 | (sender_host_address ? protocols : protocols_local) |
| 3701 | [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)]; |
| 3702 | *s = *ss = US"235 Authentication succeeded"; |
| 3703 | authenticated_by = au; |
| 3704 | break; |
| 3705 | } |
| 3706 | |
| 3707 | /* Authentication succeeded, but we failed to expand the set_id string. |
| 3708 | Treat this as a temporary error. */ |
| 3709 | |
| 3710 | auth_defer_msg = expand_string_message; |
| 3711 | /* Fall through */ |
| 3712 | |
| 3713 | case DEFER: |
| 3714 | if (set_id) authenticated_fail_id = string_copy_malloc(set_id); |
| 3715 | *s = string_sprintf("435 Unable to authenticate at present%s", |
| 3716 | auth_defer_user_msg); |
| 3717 | *ss = string_sprintf("435 Unable to authenticate at present%s: %s", |
| 3718 | set_id, auth_defer_msg); |
| 3719 | break; |
| 3720 | |
| 3721 | case BAD64: |
| 3722 | *s = *ss = US"501 Invalid base64 data"; |
| 3723 | break; |
| 3724 | |
| 3725 | case CANCELLED: |
| 3726 | *s = *ss = US"501 Authentication cancelled"; |
| 3727 | break; |
| 3728 | |
| 3729 | case UNEXPECTED: |
| 3730 | *s = *ss = US"553 Initial data not expected"; |
| 3731 | break; |
| 3732 | |
| 3733 | case FAIL: |
| 3734 | if (set_id) authenticated_fail_id = string_copy_malloc(set_id); |
| 3735 | *s = US"535 Incorrect authentication data"; |
| 3736 | *ss = string_sprintf("535 Incorrect authentication data%s", set_id); |
| 3737 | break; |
| 3738 | |
| 3739 | default: |
| 3740 | if (set_id) authenticated_fail_id = string_copy_malloc(set_id); |
| 3741 | *s = US"435 Internal error"; |
| 3742 | *ss = string_sprintf("435 Internal error%s: return %d from authentication " |
| 3743 | "check", set_id, rc); |
| 3744 | break; |
| 3745 | } |
| 3746 | |
| 3747 | return rc; |
| 3748 | } |
| 3749 | |
| 3750 | |
| 3751 | |
| 3752 | |
| 3753 | |
| 3754 | static int |
| 3755 | qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag) |
| 3756 | { |
| 3757 | int rd; |
| 3758 | if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0) |
| 3759 | { |
| 3760 | DEBUG(D_receive) debug_printf("unqualified address %s accepted\n", |
| 3761 | *recipient); |
| 3762 | rd = Ustrlen(recipient) + 1; |
| 3763 | *recipient = rewrite_address_qualify(*recipient, TRUE); |
| 3764 | return rd; |
| 3765 | } |
| 3766 | smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE, |
| 3767 | smtp_cmd_data); |
| 3768 | log_write(L_smtp_syntax_error, |
| 3769 | LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s", |
| 3770 | tag, *recipient, host_and_ident(TRUE), host_lookup_msg); |
| 3771 | return 0; |
| 3772 | } |
| 3773 | |
| 3774 | |
| 3775 | |
| 3776 | |
| 3777 | static void |
| 3778 | smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp) |
| 3779 | { |
| 3780 | HAD(SCH_QUIT); |
| 3781 | incomplete_transaction_log(US"QUIT"); |
| 3782 | if (acl_smtp_quit) |
| 3783 | { |
| 3784 | int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp); |
| 3785 | if (rc == ERROR) |
| 3786 | log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s", |
| 3787 | *log_msgp); |
| 3788 | } |
| 3789 | if (*user_msgp) |
| 3790 | smtp_respond(US"221", 3, TRUE, *user_msgp); |
| 3791 | else |
| 3792 | smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname); |
| 3793 | |
| 3794 | #ifdef SUPPORT_TLS |
| 3795 | tls_close(NULL, TLS_SHUTDOWN_NOWAIT); |
| 3796 | #endif |
| 3797 | |
| 3798 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT", |
| 3799 | smtp_get_connection_info()); |
| 3800 | } |
| 3801 | |
| 3802 | |
| 3803 | static void |
| 3804 | smtp_rset_handler(void) |
| 3805 | { |
| 3806 | HAD(SCH_RSET); |
| 3807 | incomplete_transaction_log(US"RSET"); |
| 3808 | smtp_printf("250 Reset OK\r\n", FALSE); |
| 3809 | cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE; |
| 3810 | } |
| 3811 | |
| 3812 | |
| 3813 | |
| 3814 | /************************************************* |
| 3815 | * Initialize for SMTP incoming message * |
| 3816 | *************************************************/ |
| 3817 | |
| 3818 | /* This function conducts the initial dialogue at the start of an incoming SMTP |
| 3819 | message, and builds a list of recipients. However, if the incoming message |
| 3820 | is part of a batch (-bS option) a separate function is called since it would |
| 3821 | be messy having tests splattered about all over this function. This function |
| 3822 | therefore handles the case where interaction is occurring. The input and output |
| 3823 | files are set up in smtp_in and smtp_out. |
| 3824 | |
| 3825 | The global recipients_list is set to point to a vector of recipient_item |
| 3826 | blocks, whose number is given by recipients_count. This is extended by the |
| 3827 | receive_add_recipient() function. The global variable sender_address is set to |
| 3828 | the sender's address. The yield is +1 if a message has been successfully |
| 3829 | started, 0 if a QUIT command was encountered or the connection was refused from |
| 3830 | the particular host, or -1 if the connection was lost. |
| 3831 | |
| 3832 | Argument: none |
| 3833 | |
| 3834 | Returns: > 0 message successfully started (reached DATA) |
| 3835 | = 0 QUIT read or end of file reached or call refused |
| 3836 | < 0 lost connection |
| 3837 | */ |
| 3838 | |
| 3839 | int |
| 3840 | smtp_setup_msg(void) |
| 3841 | { |
| 3842 | int done = 0; |
| 3843 | BOOL toomany = FALSE; |
| 3844 | BOOL discarded = FALSE; |
| 3845 | BOOL last_was_rej_mail = FALSE; |
| 3846 | BOOL last_was_rcpt = FALSE; |
| 3847 | void *reset_point = store_get(0); |
| 3848 | |
| 3849 | DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n"); |
| 3850 | |
| 3851 | /* Reset for start of new message. We allow one RSET not to be counted as a |
| 3852 | nonmail command, for those MTAs that insist on sending it between every |
| 3853 | message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of |
| 3854 | TLS between messages (an Exim client may do this if it has messages queued up |
| 3855 | for the host). Note: we do NOT reset AUTH at this point. */ |
| 3856 | |
| 3857 | smtp_reset(reset_point); |
| 3858 | message_ended = END_NOTSTARTED; |
| 3859 | |
| 3860 | chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED; |
| 3861 | |
| 3862 | cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE; |
| 3863 | cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE; |
| 3864 | cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE; |
| 3865 | #ifdef SUPPORT_TLS |
| 3866 | cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE; |
| 3867 | #endif |
| 3868 | |
| 3869 | /* Set the local signal handler for SIGTERM - it tries to end off tidily */ |
| 3870 | |
| 3871 | had_command_sigterm = 0; |
| 3872 | os_non_restarting_signal(SIGTERM, command_sigterm_handler); |
| 3873 | |
| 3874 | /* Batched SMTP is handled in a different function. */ |
| 3875 | |
| 3876 | if (smtp_batched_input) return smtp_setup_batch_msg(); |
| 3877 | |
| 3878 | /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE |
| 3879 | value. The values are 2 larger than the required yield of the function. */ |
| 3880 | |
| 3881 | while (done <= 0) |
| 3882 | { |
| 3883 | const uschar **argv; |
| 3884 | uschar *etrn_command; |
| 3885 | uschar *etrn_serialize_key; |
| 3886 | uschar *errmess; |
| 3887 | uschar *log_msg, *smtp_code; |
| 3888 | uschar *user_msg = NULL; |
| 3889 | uschar *recipient = NULL; |
| 3890 | uschar *hello = NULL; |
| 3891 | uschar *s, *ss; |
| 3892 | BOOL was_rej_mail = FALSE; |
| 3893 | BOOL was_rcpt = FALSE; |
| 3894 | void (*oldsignal)(int); |
| 3895 | pid_t pid; |
| 3896 | int start, end, sender_domain, recipient_domain; |
| 3897 | int rc; |
| 3898 | int c; |
| 3899 | auth_instance *au; |
| 3900 | uschar *orcpt = NULL; |
| 3901 | int flags; |
| 3902 | gstring * g; |
| 3903 | |
| 3904 | #ifdef AUTH_TLS |
| 3905 | /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */ |
| 3906 | if ( tls_in.active.sock >= 0 |
| 3907 | && tls_in.peercert |
| 3908 | && tls_in.certificate_verified |
| 3909 | && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd |
| 3910 | ) |
| 3911 | { |
| 3912 | cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE; |
| 3913 | |
| 3914 | for (au = auths; au; au = au->next) |
| 3915 | if (strcmpic(US"tls", au->driver_name) == 0) |
| 3916 | { |
| 3917 | if ( acl_smtp_auth |
| 3918 | && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, |
| 3919 | &user_msg, &log_msg)) != OK |
| 3920 | ) |
| 3921 | done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg); |
| 3922 | else |
| 3923 | { |
| 3924 | smtp_cmd_data = NULL; |
| 3925 | |
| 3926 | if (smtp_in_auth(au, &s, &ss) == OK) |
| 3927 | { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); } |
| 3928 | else |
| 3929 | { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); } |
| 3930 | } |
| 3931 | break; |
| 3932 | } |
| 3933 | } |
| 3934 | #endif |
| 3935 | |
| 3936 | #ifdef TCP_QUICKACK |
| 3937 | if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */ |
| 3938 | (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK, |
| 3939 | US &off, sizeof(off)); |
| 3940 | #endif |
| 3941 | |
| 3942 | switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED)) |
| 3943 | { |
| 3944 | /* The AUTH command is not permitted to occur inside a transaction, and may |
| 3945 | occur successfully only once per connection. Actually, that isn't quite |
| 3946 | true. When TLS is started, all previous information about a connection must |
| 3947 | be discarded, so a new AUTH is permitted at that time. |
| 3948 | |
| 3949 | AUTH may only be used when it has been advertised. However, it seems that |
| 3950 | there are clients that send AUTH when it hasn't been advertised, some of |
| 3951 | them even doing this after HELO. And there are MTAs that accept this. Sigh. |
| 3952 | So there's a get-out that allows this to happen. |
| 3953 | |
| 3954 | AUTH is initially labelled as a "nonmail command" so that one occurrence |
| 3955 | doesn't get counted. We change the label here so that multiple failing |
| 3956 | AUTHS will eventually hit the nonmail threshold. */ |
| 3957 | |
| 3958 | case AUTH_CMD: |
| 3959 | HAD(SCH_AUTH); |
| 3960 | authentication_failed = TRUE; |
| 3961 | cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE; |
| 3962 | |
| 3963 | if (!auth_advertised && !allow_auth_unadvertised) |
| 3964 | { |
| 3965 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 3966 | US"AUTH command used when not advertised"); |
| 3967 | break; |
| 3968 | } |
| 3969 | if (sender_host_authenticated) |
| 3970 | { |
| 3971 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 3972 | US"already authenticated"); |
| 3973 | break; |
| 3974 | } |
| 3975 | if (sender_address) |
| 3976 | { |
| 3977 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 3978 | US"not permitted in mail transaction"); |
| 3979 | break; |
| 3980 | } |
| 3981 | |
| 3982 | /* Check the ACL */ |
| 3983 | |
| 3984 | if ( acl_smtp_auth |
| 3985 | && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, |
| 3986 | &user_msg, &log_msg)) != OK |
| 3987 | ) |
| 3988 | { |
| 3989 | done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg); |
| 3990 | break; |
| 3991 | } |
| 3992 | |
| 3993 | /* Find the name of the requested authentication mechanism. */ |
| 3994 | |
| 3995 | s = smtp_cmd_data; |
| 3996 | while ((c = *smtp_cmd_data) != 0 && !isspace(c)) |
| 3997 | { |
| 3998 | if (!isalnum(c) && c != '-' && c != '_') |
| 3999 | { |
| 4000 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 4001 | US"invalid character in authentication mechanism name"); |
| 4002 | goto COMMAND_LOOP; |
| 4003 | } |
| 4004 | smtp_cmd_data++; |
| 4005 | } |
| 4006 | |
| 4007 | /* If not at the end of the line, we must be at white space. Terminate the |
| 4008 | name and move the pointer on to any data that may be present. */ |
| 4009 | |
| 4010 | if (*smtp_cmd_data != 0) |
| 4011 | { |
| 4012 | *smtp_cmd_data++ = 0; |
| 4013 | while (isspace(*smtp_cmd_data)) smtp_cmd_data++; |
| 4014 | } |
| 4015 | |
| 4016 | /* Search for an authentication mechanism which is configured for use |
| 4017 | as a server and which has been advertised (unless, sigh, allow_auth_ |
| 4018 | unadvertised is set). */ |
| 4019 | |
| 4020 | for (au = auths; au; au = au->next) |
| 4021 | if (strcmpic(s, au->public_name) == 0 && au->server && |
| 4022 | (au->advertised || allow_auth_unadvertised)) |
| 4023 | break; |
| 4024 | |
| 4025 | if (au) |
| 4026 | { |
| 4027 | c = smtp_in_auth(au, &s, &ss); |
| 4028 | |
| 4029 | smtp_printf("%s\r\n", FALSE, s); |
| 4030 | if (c != OK) |
| 4031 | log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s", |
| 4032 | au->name, host_and_ident(FALSE), ss); |
| 4033 | } |
| 4034 | else |
| 4035 | done = synprot_error(L_smtp_protocol_error, 504, NULL, |
| 4036 | string_sprintf("%s authentication mechanism not supported", s)); |
| 4037 | |
| 4038 | break; /* AUTH_CMD */ |
| 4039 | |
| 4040 | /* The HELO/EHLO commands are permitted to appear in the middle of a |
| 4041 | session as well as at the beginning. They have the effect of a reset in |
| 4042 | addition to their other functions. Their absence at the start cannot be |
| 4043 | taken to be an error. |
| 4044 | |
| 4045 | RFC 2821 says: |
| 4046 | |
| 4047 | If the EHLO command is not acceptable to the SMTP server, 501, 500, |
| 4048 | or 502 failure replies MUST be returned as appropriate. The SMTP |
| 4049 | server MUST stay in the same state after transmitting these replies |
| 4050 | that it was in before the EHLO was received. |
| 4051 | |
| 4052 | Therefore, we do not do the reset until after checking the command for |
| 4053 | acceptability. This change was made for Exim release 4.11. Previously |
| 4054 | it did the reset first. */ |
| 4055 | |
| 4056 | case HELO_CMD: |
| 4057 | HAD(SCH_HELO); |
| 4058 | hello = US"HELO"; |
| 4059 | esmtp = FALSE; |
| 4060 | goto HELO_EHLO; |
| 4061 | |
| 4062 | case EHLO_CMD: |
| 4063 | HAD(SCH_EHLO); |
| 4064 | hello = US"EHLO"; |
| 4065 | esmtp = TRUE; |
| 4066 | |
| 4067 | HELO_EHLO: /* Common code for HELO and EHLO */ |
| 4068 | cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE; |
| 4069 | cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE; |
| 4070 | |
| 4071 | /* Reject the HELO if its argument was invalid or non-existent. A |
| 4072 | successful check causes the argument to be saved in malloc store. */ |
| 4073 | |
| 4074 | if (!check_helo(smtp_cmd_data)) |
| 4075 | { |
| 4076 | smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello); |
| 4077 | |
| 4078 | log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically " |
| 4079 | "invalid argument(s): %s", hello, host_and_ident(FALSE), |
| 4080 | *smtp_cmd_argument == 0 ? US"(no argument given)" : |
| 4081 | string_printing(smtp_cmd_argument)); |
| 4082 | |
| 4083 | if (++synprot_error_count > smtp_max_synprot_errors) |
| 4084 | { |
| 4085 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " |
| 4086 | "syntax or protocol errors (last command was \"%s\")", |
| 4087 | host_and_ident(FALSE), string_printing(smtp_cmd_buffer)); |
| 4088 | done = 1; |
| 4089 | } |
| 4090 | |
| 4091 | break; |
| 4092 | } |
| 4093 | |
| 4094 | /* If sender_host_unknown is true, we have got here via the -bs interface, |
| 4095 | not called from inetd. Otherwise, we are running an IP connection and the |
| 4096 | host address will be set. If the helo name is the primary name of this |
| 4097 | host and we haven't done a reverse lookup, force one now. If helo_required |
| 4098 | is set, ensure that the HELO name matches the actual host. If helo_verify |
| 4099 | is set, do the same check, but softly. */ |
| 4100 | |
| 4101 | if (!sender_host_unknown) |
| 4102 | { |
| 4103 | BOOL old_helo_verified = helo_verified; |
| 4104 | uschar *p = smtp_cmd_data; |
| 4105 | |
| 4106 | while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; } |
| 4107 | *p = 0; |
| 4108 | |
| 4109 | /* Force a reverse lookup if HELO quoted something in helo_lookup_domains |
| 4110 | because otherwise the log can be confusing. */ |
| 4111 | |
| 4112 | if ( !sender_host_name |
| 4113 | && (deliver_domain = sender_helo_name, /* set $domain */ |
| 4114 | match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0, |
| 4115 | &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK) |
| 4116 | (void)host_name_lookup(); |
| 4117 | |
| 4118 | /* Rebuild the fullhost info to include the HELO name (and the real name |
| 4119 | if it was looked up.) */ |
| 4120 | |
| 4121 | host_build_sender_fullhost(); /* Rebuild */ |
| 4122 | set_process_info("handling%s incoming connection from %s", |
| 4123 | tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE)); |
| 4124 | |
| 4125 | /* Verify if configured. This doesn't give much security, but it does |
| 4126 | make some people happy to be able to do it. If helo_required is set, |
| 4127 | (host matches helo_verify_hosts) failure forces rejection. If helo_verify |
| 4128 | is set (host matches helo_try_verify_hosts), it does not. This is perhaps |
| 4129 | now obsolescent, since the verification can now be requested selectively |
| 4130 | at ACL time. */ |
| 4131 | |
| 4132 | helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE; |
| 4133 | if (helo_required || helo_verify) |
| 4134 | { |
| 4135 | BOOL tempfail = !smtp_verify_helo(); |
| 4136 | if (!helo_verified) |
| 4137 | { |
| 4138 | if (helo_required) |
| 4139 | { |
| 4140 | smtp_printf("%d %s argument does not match calling host\r\n", FALSE, |
| 4141 | tempfail? 451 : 550, hello); |
| 4142 | log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s", |
| 4143 | tempfail? "temporarily " : "", |
| 4144 | hello, sender_helo_name, host_and_ident(FALSE)); |
| 4145 | helo_verified = old_helo_verified; |
| 4146 | break; /* End of HELO/EHLO processing */ |
| 4147 | } |
| 4148 | HDEBUG(D_all) debug_printf("%s verification failed but host is in " |
| 4149 | "helo_try_verify_hosts\n", hello); |
| 4150 | } |
| 4151 | } |
| 4152 | } |
| 4153 | |
| 4154 | #ifdef SUPPORT_SPF |
| 4155 | /* set up SPF context */ |
| 4156 | spf_init(sender_helo_name, sender_host_address); |
| 4157 | #endif |
| 4158 | |
| 4159 | /* Apply an ACL check if one is defined; afterwards, recheck |
| 4160 | synchronization in case the client started sending in a delay. */ |
| 4161 | |
| 4162 | if (acl_smtp_helo) |
| 4163 | if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, |
| 4164 | &user_msg, &log_msg)) != OK) |
| 4165 | { |
| 4166 | done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg); |
| 4167 | if (sender_helo_name) |
| 4168 | { |
| 4169 | store_free(sender_helo_name); |
| 4170 | sender_helo_name = NULL; |
| 4171 | } |
| 4172 | host_build_sender_fullhost(); /* Rebuild */ |
| 4173 | break; |
| 4174 | } |
| 4175 | else if (!check_sync()) goto SYNC_FAILURE; |
| 4176 | |
| 4177 | /* Generate an OK reply. The default string includes the ident if present, |
| 4178 | and also the IP address if present. Reflecting back the ident is intended |
| 4179 | as a deterrent to mail forgers. For maximum efficiency, and also because |
| 4180 | some broken systems expect each response to be in a single packet, arrange |
| 4181 | that the entire reply is sent in one write(). */ |
| 4182 | |
| 4183 | auth_advertised = FALSE; |
| 4184 | smtp_in_pipelining_advertised = FALSE; |
| 4185 | #ifdef SUPPORT_TLS |
| 4186 | tls_advertised = FALSE; |
| 4187 | # ifdef EXPERIMENTAL_REQUIRETLS |
| 4188 | requiretls_advertised = FALSE; |
| 4189 | # endif |
| 4190 | #endif |
| 4191 | dsn_advertised = FALSE; |
| 4192 | #ifdef SUPPORT_I18N |
| 4193 | smtputf8_advertised = FALSE; |
| 4194 | #endif |
| 4195 | |
| 4196 | smtp_code = US"250 "; /* Default response code plus space*/ |
| 4197 | if (!user_msg) |
| 4198 | { |
| 4199 | s = string_sprintf("%.3s %s Hello %s%s%s", |
| 4200 | smtp_code, |
| 4201 | smtp_active_hostname, |
| 4202 | sender_ident ? sender_ident : US"", |
| 4203 | sender_ident ? US" at " : US"", |
| 4204 | sender_host_name ? sender_host_name : sender_helo_name); |
| 4205 | g = string_cat(NULL, s); |
| 4206 | |
| 4207 | if (sender_host_address) |
| 4208 | { |
| 4209 | g = string_catn(g, US" [", 2); |
| 4210 | g = string_cat (g, sender_host_address); |
| 4211 | g = string_catn(g, US"]", 1); |
| 4212 | } |
| 4213 | } |
| 4214 | |
| 4215 | /* A user-supplied EHLO greeting may not contain more than one line. Note |
| 4216 | that the code returned by smtp_message_code() includes the terminating |
| 4217 | whitespace character. */ |
| 4218 | |
| 4219 | else |
| 4220 | { |
| 4221 | char *ss; |
| 4222 | int codelen = 4; |
| 4223 | smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE); |
| 4224 | s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg); |
| 4225 | if ((ss = strpbrk(CS s, "\r\n")) != NULL) |
| 4226 | { |
| 4227 | log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain " |
| 4228 | "newlines: message truncated: %s", string_printing(s)); |
| 4229 | *ss = 0; |
| 4230 | } |
| 4231 | g = string_cat(NULL, s); |
| 4232 | } |
| 4233 | |
| 4234 | g = string_catn(g, US"\r\n", 2); |
| 4235 | |
| 4236 | /* If we received EHLO, we must create a multiline response which includes |
| 4237 | the functions supported. */ |
| 4238 | |
| 4239 | if (esmtp) |
| 4240 | { |
| 4241 | g->s[3] = '-'; |
| 4242 | |
| 4243 | /* I'm not entirely happy with this, as an MTA is supposed to check |
| 4244 | that it has enough room to accept a message of maximum size before |
| 4245 | it sends this. However, there seems little point in not sending it. |
| 4246 | The actual size check happens later at MAIL FROM time. By postponing it |
| 4247 | till then, VRFY and EXPN can be used after EHLO when space is short. */ |
| 4248 | |
| 4249 | if (thismessage_size_limit > 0) |
| 4250 | { |
| 4251 | sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code, |
| 4252 | thismessage_size_limit); |
| 4253 | g = string_cat(g, big_buffer); |
| 4254 | } |
| 4255 | else |
| 4256 | { |
| 4257 | g = string_catn(g, smtp_code, 3); |
| 4258 | g = string_catn(g, US"-SIZE\r\n", 7); |
| 4259 | } |
| 4260 | |
| 4261 | /* Exim does not do protocol conversion or data conversion. It is 8-bit |
| 4262 | clean; if it has an 8-bit character in its hand, it just sends it. It |
| 4263 | cannot therefore specify 8BITMIME and remain consistent with the RFCs. |
| 4264 | However, some users want this option simply in order to stop MUAs |
| 4265 | mangling messages that contain top-bit-set characters. It is therefore |
| 4266 | provided as an option. */ |
| 4267 | |
| 4268 | if (accept_8bitmime) |
| 4269 | { |
| 4270 | g = string_catn(g, smtp_code, 3); |
| 4271 | g = string_catn(g, US"-8BITMIME\r\n", 11); |
| 4272 | } |
| 4273 | |
| 4274 | /* Advertise DSN support if configured to do so. */ |
| 4275 | if (verify_check_host(&dsn_advertise_hosts) != FAIL) |
| 4276 | { |
| 4277 | g = string_catn(g, smtp_code, 3); |
| 4278 | g = string_catn(g, US"-DSN\r\n", 6); |
| 4279 | dsn_advertised = TRUE; |
| 4280 | } |
| 4281 | |
| 4282 | /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is |
| 4283 | permitted to issue them; a check is made when any host actually tries. */ |
| 4284 | |
| 4285 | if (acl_smtp_etrn) |
| 4286 | { |
| 4287 | g = string_catn(g, smtp_code, 3); |
| 4288 | g = string_catn(g, US"-ETRN\r\n", 7); |
| 4289 | } |
| 4290 | if (acl_smtp_vrfy) |
| 4291 | { |
| 4292 | g = string_catn(g, smtp_code, 3); |
| 4293 | g = string_catn(g, US"-VRFY\r\n", 7); |
| 4294 | } |
| 4295 | if (acl_smtp_expn) |
| 4296 | { |
| 4297 | g = string_catn(g, smtp_code, 3); |
| 4298 | g = string_catn(g, US"-EXPN\r\n", 7); |
| 4299 | } |
| 4300 | |
| 4301 | /* Exim is quite happy with pipelining, so let the other end know that |
| 4302 | it is safe to use it, unless advertising is disabled. */ |
| 4303 | |
| 4304 | if (pipelining_enable && |
| 4305 | verify_check_host(&pipelining_advertise_hosts) == OK) |
| 4306 | { |
| 4307 | g = string_catn(g, smtp_code, 3); |
| 4308 | g = string_catn(g, US"-PIPELINING\r\n", 13); |
| 4309 | sync_cmd_limit = NON_SYNC_CMD_PIPELINING; |
| 4310 | smtp_in_pipelining_advertised = TRUE; |
| 4311 | } |
| 4312 | |
| 4313 | |
| 4314 | /* If any server authentication mechanisms are configured, advertise |
| 4315 | them if the current host is in auth_advertise_hosts. The problem with |
| 4316 | advertising always is that some clients then require users to |
| 4317 | authenticate (and aren't configurable otherwise) even though it may not |
| 4318 | be necessary (e.g. if the host is in host_accept_relay). |
| 4319 | |
| 4320 | RFC 2222 states that SASL mechanism names contain only upper case |
| 4321 | letters, so output the names in upper case, though we actually recognize |
| 4322 | them in either case in the AUTH command. */ |
| 4323 | |
| 4324 | if ( auths |
| 4325 | #ifdef AUTH_TLS |
| 4326 | && !sender_host_authenticated |
| 4327 | #endif |
| 4328 | && verify_check_host(&auth_advertise_hosts) == OK |
| 4329 | ) |
| 4330 | { |
| 4331 | auth_instance *au; |
| 4332 | BOOL first = TRUE; |
| 4333 | for (au = auths; au; au = au->next) |
| 4334 | { |
| 4335 | au->advertised = FALSE; |
| 4336 | if (au->server) |
| 4337 | { |
| 4338 | DEBUG(D_auth+D_expand) debug_printf_indent( |
| 4339 | "Evaluating advertise_condition for %s athenticator\n", |
| 4340 | au->public_name); |
| 4341 | if ( !au->advertise_condition |
| 4342 | || expand_check_condition(au->advertise_condition, au->name, |
| 4343 | US"authenticator") |
| 4344 | ) |
| 4345 | { |
| 4346 | int saveptr; |
| 4347 | if (first) |
| 4348 | { |
| 4349 | g = string_catn(g, smtp_code, 3); |
| 4350 | g = string_catn(g, US"-AUTH", 5); |
| 4351 | first = FALSE; |
| 4352 | auth_advertised = TRUE; |
| 4353 | } |
| 4354 | saveptr = g->ptr; |
| 4355 | g = string_catn(g, US" ", 1); |
| 4356 | g = string_cat (g, au->public_name); |
| 4357 | while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]); |
| 4358 | au->advertised = TRUE; |
| 4359 | } |
| 4360 | } |
| 4361 | } |
| 4362 | |
| 4363 | if (!first) g = string_catn(g, US"\r\n", 2); |
| 4364 | } |
| 4365 | |
| 4366 | /* RFC 3030 CHUNKING */ |
| 4367 | |
| 4368 | if (verify_check_host(&chunking_advertise_hosts) != FAIL) |
| 4369 | { |
| 4370 | g = string_catn(g, smtp_code, 3); |
| 4371 | g = string_catn(g, US"-CHUNKING\r\n", 11); |
| 4372 | chunking_offered = TRUE; |
| 4373 | chunking_state = CHUNKING_OFFERED; |
| 4374 | } |
| 4375 | |
| 4376 | /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer) |
| 4377 | if it has been included in the binary, and the host matches |
| 4378 | tls_advertise_hosts. We must *not* advertise if we are already in a |
| 4379 | secure connection. */ |
| 4380 | |
| 4381 | #ifdef SUPPORT_TLS |
| 4382 | if (tls_in.active.sock < 0 && |
| 4383 | verify_check_host(&tls_advertise_hosts) != FAIL) |
| 4384 | { |
| 4385 | g = string_catn(g, smtp_code, 3); |
| 4386 | g = string_catn(g, US"-STARTTLS\r\n", 11); |
| 4387 | tls_advertised = TRUE; |
| 4388 | } |
| 4389 | |
| 4390 | # ifdef EXPERIMENTAL_REQUIRETLS |
| 4391 | /* Advertise REQUIRETLS only once we are in a secure connection */ |
| 4392 | if ( tls_in.active.sock >= 0 |
| 4393 | && verify_check_host(&tls_advertise_requiretls) != FAIL) |
| 4394 | { |
| 4395 | g = string_catn(g, smtp_code, 3); |
| 4396 | g = string_catn(g, US"-REQUIRETLS\r\n", 13); |
| 4397 | requiretls_advertised = TRUE; |
| 4398 | } |
| 4399 | # endif |
| 4400 | #endif |
| 4401 | |
| 4402 | #ifndef DISABLE_PRDR |
| 4403 | /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */ |
| 4404 | if (prdr_enable) |
| 4405 | { |
| 4406 | g = string_catn(g, smtp_code, 3); |
| 4407 | g = string_catn(g, US"-PRDR\r\n", 7); |
| 4408 | } |
| 4409 | #endif |
| 4410 | |
| 4411 | #ifdef SUPPORT_I18N |
| 4412 | if ( accept_8bitmime |
| 4413 | && verify_check_host(&smtputf8_advertise_hosts) != FAIL) |
| 4414 | { |
| 4415 | g = string_catn(g, smtp_code, 3); |
| 4416 | g = string_catn(g, US"-SMTPUTF8\r\n", 11); |
| 4417 | smtputf8_advertised = TRUE; |
| 4418 | } |
| 4419 | #endif |
| 4420 | |
| 4421 | /* Finish off the multiline reply with one that is always available. */ |
| 4422 | |
| 4423 | g = string_catn(g, smtp_code, 3); |
| 4424 | g = string_catn(g, US" HELP\r\n", 7); |
| 4425 | } |
| 4426 | |
| 4427 | /* Terminate the string (for debug), write it, and note that HELO/EHLO |
| 4428 | has been seen. */ |
| 4429 | |
| 4430 | #ifdef SUPPORT_TLS |
| 4431 | if (tls_in.active.sock >= 0) (void)tls_write(NULL, g->s, g->ptr, FALSE); else |
| 4432 | #endif |
| 4433 | |
| 4434 | { |
| 4435 | int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */ |
| 4436 | } |
| 4437 | DEBUG(D_receive) |
| 4438 | { |
| 4439 | uschar *cr; |
| 4440 | |
| 4441 | (void) string_from_gstring(g); |
| 4442 | while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */ |
| 4443 | memmove(cr, cr + 1, (g->ptr--) - (cr - g->s)); |
| 4444 | debug_printf("SMTP>> %s", g->s); |
| 4445 | } |
| 4446 | helo_seen = TRUE; |
| 4447 | |
| 4448 | /* Reset the protocol and the state, abandoning any previous message. */ |
| 4449 | received_protocol = |
| 4450 | (sender_host_address ? protocols : protocols_local) |
| 4451 | [ (esmtp |
| 4452 | ? pextend + (sender_host_authenticated ? pauthed : 0) |
| 4453 | : pnormal) |
| 4454 | + (tls_in.active.sock >= 0 ? pcrpted : 0) |
| 4455 | ]; |
| 4456 | cancel_cutthrough_connection(TRUE, US"sent EHLO response"); |
| 4457 | smtp_reset(reset_point); |
| 4458 | toomany = FALSE; |
| 4459 | break; /* HELO/EHLO */ |
| 4460 | |
| 4461 | |
| 4462 | /* The MAIL command requires an address as an operand. All we do |
| 4463 | here is to parse it for syntactic correctness. The form "<>" is |
| 4464 | a special case which converts into an empty string. The start/end |
| 4465 | pointers in the original are not used further for this address, as |
| 4466 | it is the canonical extracted address which is all that is kept. */ |
| 4467 | |
| 4468 | case MAIL_CMD: |
| 4469 | HAD(SCH_MAIL); |
| 4470 | smtp_mailcmd_count++; /* Count for limit and ratelimit */ |
| 4471 | was_rej_mail = TRUE; /* Reset if accepted */ |
| 4472 | env_mail_type_t * mail_args; /* Sanity check & validate args */ |
| 4473 | |
| 4474 | if (helo_required && !helo_seen) |
| 4475 | { |
| 4476 | smtp_printf("503 HELO or EHLO required\r\n", FALSE); |
| 4477 | log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no " |
| 4478 | "HELO/EHLO given", host_and_ident(FALSE)); |
| 4479 | break; |
| 4480 | } |
| 4481 | |
| 4482 | if (sender_address) |
| 4483 | { |
| 4484 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 4485 | US"sender already given"); |
| 4486 | break; |
| 4487 | } |
| 4488 | |
| 4489 | if (!*smtp_cmd_data) |
| 4490 | { |
| 4491 | done = synprot_error(L_smtp_protocol_error, 501, NULL, |
| 4492 | US"MAIL must have an address operand"); |
| 4493 | break; |
| 4494 | } |
| 4495 | |
| 4496 | /* Check to see if the limit for messages per connection would be |
| 4497 | exceeded by accepting further messages. */ |
| 4498 | |
| 4499 | if (smtp_accept_max_per_connection > 0 && |
| 4500 | smtp_mailcmd_count > smtp_accept_max_per_connection) |
| 4501 | { |
| 4502 | smtp_printf("421 too many messages in this connection\r\n", FALSE); |
| 4503 | log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many " |
| 4504 | "messages in one connection", host_and_ident(TRUE)); |
| 4505 | break; |
| 4506 | } |
| 4507 | |
| 4508 | /* Reset for start of message - even if this is going to fail, we |
| 4509 | obviously need to throw away any previous data. */ |
| 4510 | |
| 4511 | cancel_cutthrough_connection(TRUE, US"MAIL received"); |
| 4512 | smtp_reset(reset_point); |
| 4513 | toomany = FALSE; |
| 4514 | sender_data = recipient_data = NULL; |
| 4515 | |
| 4516 | /* Loop, checking for ESMTP additions to the MAIL FROM command. */ |
| 4517 | |
| 4518 | if (esmtp) for(;;) |
| 4519 | { |
| 4520 | uschar *name, *value, *end; |
| 4521 | unsigned long int size; |
| 4522 | BOOL arg_error = FALSE; |
| 4523 | |
| 4524 | if (!extract_option(&name, &value)) break; |
| 4525 | |
| 4526 | for (mail_args = env_mail_type_list; |
| 4527 | mail_args->value != ENV_MAIL_OPT_NULL; |
| 4528 | mail_args++ |
| 4529 | ) |
| 4530 | if (strcmpic(name, mail_args->name) == 0) |
| 4531 | break; |
| 4532 | if (mail_args->need_value && strcmpic(value, US"") == 0) |
| 4533 | break; |
| 4534 | |
| 4535 | switch(mail_args->value) |
| 4536 | { |
| 4537 | /* Handle SIZE= by reading the value. We don't do the check till later, |
| 4538 | in order to be able to log the sender address on failure. */ |
| 4539 | case ENV_MAIL_OPT_SIZE: |
| 4540 | if (((size = Ustrtoul(value, &end, 10)), *end == 0)) |
| 4541 | { |
| 4542 | if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX) |
| 4543 | size = INT_MAX; |
| 4544 | message_size = (int)size; |
| 4545 | } |
| 4546 | else |
| 4547 | arg_error = TRUE; |
| 4548 | break; |
| 4549 | |
| 4550 | /* If this session was initiated with EHLO and accept_8bitmime is set, |
| 4551 | Exim will have indicated that it supports the BODY=8BITMIME option. In |
| 4552 | fact, it does not support this according to the RFCs, in that it does not |
| 4553 | take any special action for forwarding messages containing 8-bit |
| 4554 | characters. That is why accept_8bitmime is not the default setting, but |
| 4555 | some sites want the action that is provided. We recognize both "8BITMIME" |
| 4556 | and "7BIT" as body types, but take no action. */ |
| 4557 | case ENV_MAIL_OPT_BODY: |
| 4558 | if (accept_8bitmime) { |
| 4559 | if (strcmpic(value, US"8BITMIME") == 0) |
| 4560 | body_8bitmime = 8; |
| 4561 | else if (strcmpic(value, US"7BIT") == 0) |
| 4562 | body_8bitmime = 7; |
| 4563 | else |
| 4564 | { |
| 4565 | body_8bitmime = 0; |
| 4566 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 4567 | US"invalid data for BODY"); |
| 4568 | goto COMMAND_LOOP; |
| 4569 | } |
| 4570 | DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime); |
| 4571 | break; |
| 4572 | } |
| 4573 | arg_error = TRUE; |
| 4574 | break; |
| 4575 | |
| 4576 | /* Handle the two DSN options, but only if configured to do so (which |
| 4577 | will have caused "DSN" to be given in the EHLO response). The code itself |
| 4578 | is included only if configured in at build time. */ |
| 4579 | |
| 4580 | case ENV_MAIL_OPT_RET: |
| 4581 | if (dsn_advertised) |
| 4582 | { |
| 4583 | /* Check if RET has already been set */ |
| 4584 | if (dsn_ret > 0) |
| 4585 | { |
| 4586 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 4587 | US"RET can be specified once only"); |
| 4588 | goto COMMAND_LOOP; |
| 4589 | } |
| 4590 | dsn_ret = strcmpic(value, US"HDRS") == 0 |
| 4591 | ? dsn_ret_hdrs |
| 4592 | : strcmpic(value, US"FULL") == 0 |
| 4593 | ? dsn_ret_full |
| 4594 | : 0; |
| 4595 | DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret); |
| 4596 | /* Check for invalid invalid value, and exit with error */ |
| 4597 | if (dsn_ret == 0) |
| 4598 | { |
| 4599 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 4600 | US"Value for RET is invalid"); |
| 4601 | goto COMMAND_LOOP; |
| 4602 | } |
| 4603 | } |
| 4604 | break; |
| 4605 | case ENV_MAIL_OPT_ENVID: |
| 4606 | if (dsn_advertised) |
| 4607 | { |
| 4608 | /* Check if the dsn envid has been already set */ |
| 4609 | if (dsn_envid) |
| 4610 | { |
| 4611 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 4612 | US"ENVID can be specified once only"); |
| 4613 | goto COMMAND_LOOP; |
| 4614 | } |
| 4615 | dsn_envid = string_copy(value); |
| 4616 | DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid); |
| 4617 | } |
| 4618 | break; |
| 4619 | |
| 4620 | /* Handle the AUTH extension. If the value given is not "<>" and either |
| 4621 | the ACL says "yes" or there is no ACL but the sending host is |
| 4622 | authenticated, we set it up as the authenticated sender. However, if the |
| 4623 | authenticator set a condition to be tested, we ignore AUTH on MAIL unless |
| 4624 | the condition is met. The value of AUTH is an xtext, which means that +, |
| 4625 | = and cntrl chars are coded in hex; however "<>" is unaffected by this |
| 4626 | coding. */ |
| 4627 | case ENV_MAIL_OPT_AUTH: |
| 4628 | if (Ustrcmp(value, "<>") != 0) |
| 4629 | { |
| 4630 | int rc; |
| 4631 | uschar *ignore_msg; |
| 4632 | |
| 4633 | if (auth_xtextdecode(value, &authenticated_sender) < 0) |
| 4634 | { |
| 4635 | /* Put back terminator overrides for error message */ |
| 4636 | value[-1] = '='; |
| 4637 | name[-1] = ' '; |
| 4638 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 4639 | US"invalid data for AUTH"); |
| 4640 | goto COMMAND_LOOP; |
| 4641 | } |
| 4642 | if (!acl_smtp_mailauth) |
| 4643 | { |
| 4644 | ignore_msg = US"client not authenticated"; |
| 4645 | rc = sender_host_authenticated ? OK : FAIL; |
| 4646 | } |
| 4647 | else |
| 4648 | { |
| 4649 | ignore_msg = US"rejected by ACL"; |
| 4650 | rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth, |
| 4651 | &user_msg, &log_msg); |
| 4652 | } |
| 4653 | |
| 4654 | switch (rc) |
| 4655 | { |
| 4656 | case OK: |
| 4657 | if (authenticated_by == NULL || |
| 4658 | authenticated_by->mail_auth_condition == NULL || |
| 4659 | expand_check_condition(authenticated_by->mail_auth_condition, |
| 4660 | authenticated_by->name, US"authenticator")) |
| 4661 | break; /* Accept the AUTH */ |
| 4662 | |
| 4663 | ignore_msg = US"server_mail_auth_condition failed"; |
| 4664 | if (authenticated_id != NULL) |
| 4665 | ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"", |
| 4666 | ignore_msg, authenticated_id); |
| 4667 | |
| 4668 | /* Fall through */ |
| 4669 | |
| 4670 | case FAIL: |
| 4671 | authenticated_sender = NULL; |
| 4672 | log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)", |
| 4673 | value, host_and_ident(TRUE), ignore_msg); |
| 4674 | break; |
| 4675 | |
| 4676 | /* Should only get DEFER or ERROR here. Put back terminator |
| 4677 | overrides for error message */ |
| 4678 | |
| 4679 | default: |
| 4680 | value[-1] = '='; |
| 4681 | name[-1] = ' '; |
| 4682 | (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg, |
| 4683 | log_msg); |
| 4684 | goto COMMAND_LOOP; |
| 4685 | } |
| 4686 | } |
| 4687 | break; |
| 4688 | |
| 4689 | #ifndef DISABLE_PRDR |
| 4690 | case ENV_MAIL_OPT_PRDR: |
| 4691 | if (prdr_enable) |
| 4692 | prdr_requested = TRUE; |
| 4693 | break; |
| 4694 | #endif |
| 4695 | |
| 4696 | #ifdef SUPPORT_I18N |
| 4697 | case ENV_MAIL_OPT_UTF8: |
| 4698 | if (!smtputf8_advertised) |
| 4699 | { |
| 4700 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 4701 | US"SMTPUTF8 used when not advertised"); |
| 4702 | goto COMMAND_LOOP; |
| 4703 | } |
| 4704 | |
| 4705 | DEBUG(D_receive) debug_printf("smtputf8 requested\n"); |
| 4706 | message_smtputf8 = allow_utf8_domains = TRUE; |
| 4707 | if (Ustrncmp(received_protocol, US"utf8", 4) != 0) |
| 4708 | { |
| 4709 | int old_pool = store_pool; |
| 4710 | store_pool = POOL_PERM; |
| 4711 | received_protocol = string_sprintf("utf8%s", received_protocol); |
| 4712 | store_pool = old_pool; |
| 4713 | } |
| 4714 | break; |
| 4715 | #endif |
| 4716 | |
| 4717 | #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS) |
| 4718 | case ENV_MAIL_OPT_REQTLS: |
| 4719 | { |
| 4720 | const uschar * list = value; |
| 4721 | int sep = ','; |
| 4722 | const uschar * opt; |
| 4723 | uschar * r, * t; |
| 4724 | |
| 4725 | if (!requiretls_advertised) |
| 4726 | { |
| 4727 | done = synprot_error(L_smtp_syntax_error, 555, NULL, |
| 4728 | US"unadvertised MAIL option: REQUIRETLS"); |
| 4729 | goto COMMAND_LOOP; |
| 4730 | } |
| 4731 | |
| 4732 | DEBUG(D_receive) debug_printf("requiretls requested\n"); |
| 4733 | tls_requiretls = REQUIRETLS_MSG; |
| 4734 | |
| 4735 | r = string_copy_malloc(received_protocol); |
| 4736 | if ((t = Ustrrchr(r, 's'))) *t = 'S'; |
| 4737 | received_protocol = r; |
| 4738 | } |
| 4739 | break; |
| 4740 | #endif |
| 4741 | |
| 4742 | /* No valid option. Stick back the terminator characters and break |
| 4743 | the loop. Do the name-terminator second as extract_option sets |
| 4744 | value==name when it found no equal-sign. |
| 4745 | An error for a malformed address will occur. */ |
| 4746 | case ENV_MAIL_OPT_NULL: |
| 4747 | value[-1] = '='; |
| 4748 | name[-1] = ' '; |
| 4749 | arg_error = TRUE; |
| 4750 | break; |
| 4751 | |
| 4752 | default: assert(0); |
| 4753 | } |
| 4754 | /* Break out of for loop if switch() had bad argument or |
| 4755 | when start of the email address is reached */ |
| 4756 | if (arg_error) break; |
| 4757 | } |
| 4758 | |
| 4759 | #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS) |
| 4760 | if (tls_requiretls & REQUIRETLS_MSG) |
| 4761 | { |
| 4762 | /* Ensure headers-only bounces whether a RET option was given or not. */ |
| 4763 | |
| 4764 | DEBUG(D_receive) if (dsn_ret == dsn_ret_full) |
| 4765 | debug_printf("requiretls override: dsn_ret_full -> dsn_ret_hdrs\n"); |
| 4766 | dsn_ret = dsn_ret_hdrs; |
| 4767 | } |
| 4768 | #endif |
| 4769 | |
| 4770 | /* If we have passed the threshold for rate limiting, apply the current |
| 4771 | delay, and update it for next time, provided this is a limited host. */ |
| 4772 | |
| 4773 | if (smtp_mailcmd_count > smtp_rlm_threshold && |
| 4774 | verify_check_host(&smtp_ratelimit_hosts) == OK) |
| 4775 | { |
| 4776 | DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n", |
| 4777 | smtp_delay_mail/1000.0); |
| 4778 | millisleep((int)smtp_delay_mail); |
| 4779 | smtp_delay_mail *= smtp_rlm_factor; |
| 4780 | if (smtp_delay_mail > (double)smtp_rlm_limit) |
| 4781 | smtp_delay_mail = (double)smtp_rlm_limit; |
| 4782 | } |
| 4783 | |
| 4784 | /* Now extract the address, first applying any SMTP-time rewriting. The |
| 4785 | TRUE flag allows "<>" as a sender address. */ |
| 4786 | |
| 4787 | raw_sender = rewrite_existflags & rewrite_smtp |
| 4788 | ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"", |
| 4789 | global_rewrite_rules) |
| 4790 | : smtp_cmd_data; |
| 4791 | |
| 4792 | raw_sender = |
| 4793 | parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain, |
| 4794 | TRUE); |
| 4795 | |
| 4796 | if (!raw_sender) |
| 4797 | { |
| 4798 | done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess); |
| 4799 | break; |
| 4800 | } |
| 4801 | |
| 4802 | sender_address = raw_sender; |
| 4803 | |
| 4804 | /* If there is a configured size limit for mail, check that this message |
| 4805 | doesn't exceed it. The check is postponed to this point so that the sender |
| 4806 | can be logged. */ |
| 4807 | |
| 4808 | if (thismessage_size_limit > 0 && message_size > thismessage_size_limit) |
| 4809 | { |
| 4810 | smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE); |
| 4811 | log_write(L_size_reject, |
| 4812 | LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: " |
| 4813 | "message too big: size%s=%d max=%d", |
| 4814 | sender_address, |
| 4815 | host_and_ident(TRUE), |
| 4816 | (message_size == INT_MAX)? ">" : "", |
| 4817 | message_size, |
| 4818 | thismessage_size_limit); |
| 4819 | sender_address = NULL; |
| 4820 | break; |
| 4821 | } |
| 4822 | |
| 4823 | /* Check there is enough space on the disk unless configured not to. |
| 4824 | When smtp_check_spool_space is set, the check is for thismessage_size_limit |
| 4825 | plus the current message - i.e. we accept the message only if it won't |
| 4826 | reduce the space below the threshold. Add 5000 to the size to allow for |
| 4827 | overheads such as the Received: line and storing of recipients, etc. |
| 4828 | By putting the check here, even when SIZE is not given, it allow VRFY |
| 4829 | and EXPN etc. to be used when space is short. */ |
| 4830 | |
| 4831 | if (!receive_check_fs( |
| 4832 | (smtp_check_spool_space && message_size >= 0)? |
| 4833 | message_size + 5000 : 0)) |
| 4834 | { |
| 4835 | smtp_printf("452 Space shortage, please try later\r\n", FALSE); |
| 4836 | sender_address = NULL; |
| 4837 | break; |
| 4838 | } |
| 4839 | |
| 4840 | /* If sender_address is unqualified, reject it, unless this is a locally |
| 4841 | generated message, or the sending host or net is permitted to send |
| 4842 | unqualified addresses - typically local machines behaving as MUAs - |
| 4843 | in which case just qualify the address. The flag is set above at the start |
| 4844 | of the SMTP connection. */ |
| 4845 | |
| 4846 | if (!sender_domain && *sender_address) |
| 4847 | if (allow_unqualified_sender) |
| 4848 | { |
| 4849 | sender_domain = Ustrlen(sender_address) + 1; |
| 4850 | sender_address = rewrite_address_qualify(sender_address, FALSE); |
| 4851 | DEBUG(D_receive) debug_printf("unqualified address %s accepted\n", |
| 4852 | raw_sender); |
| 4853 | } |
| 4854 | else |
| 4855 | { |
| 4856 | smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE, |
| 4857 | smtp_cmd_data); |
| 4858 | log_write(L_smtp_syntax_error, |
| 4859 | LOG_MAIN|LOG_REJECT, |
| 4860 | "unqualified sender rejected: <%s> %s%s", |
| 4861 | raw_sender, |
| 4862 | host_and_ident(TRUE), |
| 4863 | host_lookup_msg); |
| 4864 | sender_address = NULL; |
| 4865 | break; |
| 4866 | } |
| 4867 | |
| 4868 | /* Apply an ACL check if one is defined, before responding. Afterwards, |
| 4869 | when pipelining is not advertised, do another sync check in case the ACL |
| 4870 | delayed and the client started sending in the meantime. */ |
| 4871 | |
| 4872 | if (acl_smtp_mail) |
| 4873 | { |
| 4874 | rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg); |
| 4875 | if (rc == OK && !smtp_in_pipelining_advertised && !check_sync()) |
| 4876 | goto SYNC_FAILURE; |
| 4877 | } |
| 4878 | else |
| 4879 | rc = OK; |
| 4880 | |
| 4881 | if (rc == OK || rc == DISCARD) |
| 4882 | { |
| 4883 | BOOL more = pipeline_response(); |
| 4884 | |
| 4885 | if (!user_msg) |
| 4886 | smtp_printf("%s%s%s", more, US"250 OK", |
| 4887 | #ifndef DISABLE_PRDR |
| 4888 | prdr_requested ? US", PRDR Requested" : US"", |
| 4889 | #else |
| 4890 | US"", |
| 4891 | #endif |
| 4892 | US"\r\n"); |
| 4893 | else |
| 4894 | { |
| 4895 | #ifndef DISABLE_PRDR |
| 4896 | if (prdr_requested) |
| 4897 | user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested"); |
| 4898 | #endif |
| 4899 | smtp_user_msg(US"250", user_msg); |
| 4900 | } |
| 4901 | smtp_delay_rcpt = smtp_rlr_base; |
| 4902 | recipients_discarded = (rc == DISCARD); |
| 4903 | was_rej_mail = FALSE; |
| 4904 | } |
| 4905 | else |
| 4906 | { |
| 4907 | done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg); |
| 4908 | sender_address = NULL; |
| 4909 | } |
| 4910 | break; |
| 4911 | |
| 4912 | |
| 4913 | /* The RCPT command requires an address as an operand. There may be any |
| 4914 | number of RCPT commands, specifying multiple recipients. We build them all |
| 4915 | into a data structure. The start/end values given by parse_extract_address |
| 4916 | are not used, as we keep only the extracted address. */ |
| 4917 | |
| 4918 | case RCPT_CMD: |
| 4919 | HAD(SCH_RCPT); |
| 4920 | rcpt_count++; |
| 4921 | was_rcpt = rcpt_in_progress = TRUE; |
| 4922 | |
| 4923 | /* There must be a sender address; if the sender was rejected and |
| 4924 | pipelining was advertised, we assume the client was pipelining, and do not |
| 4925 | count this as a protocol error. Reset was_rej_mail so that further RCPTs |
| 4926 | get the same treatment. */ |
| 4927 | |
| 4928 | if (sender_address == NULL) |
| 4929 | { |
| 4930 | if (smtp_in_pipelining_advertised && last_was_rej_mail) |
| 4931 | { |
| 4932 | smtp_printf("503 sender not yet given\r\n", FALSE); |
| 4933 | was_rej_mail = TRUE; |
| 4934 | } |
| 4935 | else |
| 4936 | { |
| 4937 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 4938 | US"sender not yet given"); |
| 4939 | was_rcpt = FALSE; /* Not a valid RCPT */ |
| 4940 | } |
| 4941 | rcpt_fail_count++; |
| 4942 | break; |
| 4943 | } |
| 4944 | |
| 4945 | /* Check for an operand */ |
| 4946 | |
| 4947 | if (smtp_cmd_data[0] == 0) |
| 4948 | { |
| 4949 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 4950 | US"RCPT must have an address operand"); |
| 4951 | rcpt_fail_count++; |
| 4952 | break; |
| 4953 | } |
| 4954 | |
| 4955 | /* Set the DSN flags orcpt and dsn_flags from the session*/ |
| 4956 | orcpt = NULL; |
| 4957 | flags = 0; |
| 4958 | |
| 4959 | if (esmtp) for(;;) |
| 4960 | { |
| 4961 | uschar *name, *value; |
| 4962 | |
| 4963 | if (!extract_option(&name, &value)) |
| 4964 | break; |
| 4965 | |
| 4966 | if (dsn_advertised && strcmpic(name, US"ORCPT") == 0) |
| 4967 | { |
| 4968 | /* Check whether orcpt has been already set */ |
| 4969 | if (orcpt) |
| 4970 | { |
| 4971 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 4972 | US"ORCPT can be specified once only"); |
| 4973 | goto COMMAND_LOOP; |
| 4974 | } |
| 4975 | orcpt = string_copy(value); |
| 4976 | DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt); |
| 4977 | } |
| 4978 | |
| 4979 | else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0) |
| 4980 | { |
| 4981 | /* Check if the notify flags have been already set */ |
| 4982 | if (flags > 0) |
| 4983 | { |
| 4984 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 4985 | US"NOTIFY can be specified once only"); |
| 4986 | goto COMMAND_LOOP; |
| 4987 | } |
| 4988 | if (strcmpic(value, US"NEVER") == 0) |
| 4989 | flags |= rf_notify_never; |
| 4990 | else |
| 4991 | { |
| 4992 | uschar *p = value; |
| 4993 | while (*p != 0) |
| 4994 | { |
| 4995 | uschar *pp = p; |
| 4996 | while (*pp != 0 && *pp != ',') pp++; |
| 4997 | if (*pp == ',') *pp++ = 0; |
| 4998 | if (strcmpic(p, US"SUCCESS") == 0) |
| 4999 | { |
| 5000 | DEBUG(D_receive) debug_printf("DSN: Setting notify success\n"); |
| 5001 | flags |= rf_notify_success; |
| 5002 | } |
| 5003 | else if (strcmpic(p, US"FAILURE") == 0) |
| 5004 | { |
| 5005 | DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n"); |
| 5006 | flags |= rf_notify_failure; |
| 5007 | } |
| 5008 | else if (strcmpic(p, US"DELAY") == 0) |
| 5009 | { |
| 5010 | DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n"); |
| 5011 | flags |= rf_notify_delay; |
| 5012 | } |
| 5013 | else |
| 5014 | { |
| 5015 | /* Catch any strange values */ |
| 5016 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 5017 | US"Invalid value for NOTIFY parameter"); |
| 5018 | goto COMMAND_LOOP; |
| 5019 | } |
| 5020 | p = pp; |
| 5021 | } |
| 5022 | DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags); |
| 5023 | } |
| 5024 | } |
| 5025 | |
| 5026 | /* Unknown option. Stick back the terminator characters and break |
| 5027 | the loop. An error for a malformed address will occur. */ |
| 5028 | |
| 5029 | else |
| 5030 | { |
| 5031 | DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value); |
| 5032 | name[-1] = ' '; |
| 5033 | value[-1] = '='; |
| 5034 | break; |
| 5035 | } |
| 5036 | } |
| 5037 | |
| 5038 | /* Apply SMTP rewriting then extract the working address. Don't allow "<>" |
| 5039 | as a recipient address */ |
| 5040 | |
| 5041 | recipient = rewrite_existflags & rewrite_smtp |
| 5042 | ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"", |
| 5043 | global_rewrite_rules) |
| 5044 | : smtp_cmd_data; |
| 5045 | |
| 5046 | if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end, |
| 5047 | &recipient_domain, FALSE))) |
| 5048 | { |
| 5049 | done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess); |
| 5050 | rcpt_fail_count++; |
| 5051 | break; |
| 5052 | } |
| 5053 | |
| 5054 | /* If the recipient address is unqualified, reject it, unless this is a |
| 5055 | locally generated message. However, unqualified addresses are permitted |
| 5056 | from a configured list of hosts and nets - typically when behaving as |
| 5057 | MUAs rather than MTAs. Sad that SMTP is used for both types of traffic, |
| 5058 | really. The flag is set at the start of the SMTP connection. |
| 5059 | |
| 5060 | RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always |
| 5061 | assumed this meant "reserved local part", but the revision of RFC 821 and |
| 5062 | friends now makes it absolutely clear that it means *mailbox*. Consequently |
| 5063 | we must always qualify this address, regardless. */ |
| 5064 | |
| 5065 | if (!recipient_domain) |
| 5066 | if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data, |
| 5067 | US"recipient"))) |
| 5068 | { |
| 5069 | rcpt_fail_count++; |
| 5070 | break; |
| 5071 | } |
| 5072 | |
| 5073 | /* Check maximum allowed */ |
| 5074 | |
| 5075 | if (rcpt_count > recipients_max && recipients_max > 0) |
| 5076 | { |
| 5077 | if (recipients_max_reject) |
| 5078 | { |
| 5079 | rcpt_fail_count++; |
| 5080 | smtp_printf("552 too many recipients\r\n", FALSE); |
| 5081 | if (!toomany) |
| 5082 | log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message " |
| 5083 | "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE)); |
| 5084 | } |
| 5085 | else |
| 5086 | { |
| 5087 | rcpt_defer_count++; |
| 5088 | smtp_printf("452 too many recipients\r\n", FALSE); |
| 5089 | if (!toomany) |
| 5090 | log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess " |
| 5091 | "temporarily rejected: sender=<%s> %s", sender_address, |
| 5092 | host_and_ident(TRUE)); |
| 5093 | } |
| 5094 | |
| 5095 | toomany = TRUE; |
| 5096 | break; |
| 5097 | } |
| 5098 | |
| 5099 | /* If we have passed the threshold for rate limiting, apply the current |
| 5100 | delay, and update it for next time, provided this is a limited host. */ |
| 5101 | |
| 5102 | if (rcpt_count > smtp_rlr_threshold && |
| 5103 | verify_check_host(&smtp_ratelimit_hosts) == OK) |
| 5104 | { |
| 5105 | DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n", |
| 5106 | smtp_delay_rcpt/1000.0); |
| 5107 | millisleep((int)smtp_delay_rcpt); |
| 5108 | smtp_delay_rcpt *= smtp_rlr_factor; |
| 5109 | if (smtp_delay_rcpt > (double)smtp_rlr_limit) |
| 5110 | smtp_delay_rcpt = (double)smtp_rlr_limit; |
| 5111 | } |
| 5112 | |
| 5113 | /* If the MAIL ACL discarded all the recipients, we bypass ACL checking |
| 5114 | for them. Otherwise, check the access control list for this recipient. As |
| 5115 | there may be a delay in this, re-check for a synchronization error |
| 5116 | afterwards, unless pipelining was advertised. */ |
| 5117 | |
| 5118 | if (recipients_discarded) |
| 5119 | rc = DISCARD; |
| 5120 | else |
| 5121 | if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, |
| 5122 | &log_msg)) == OK |
| 5123 | && !smtp_in_pipelining_advertised && !check_sync()) |
| 5124 | goto SYNC_FAILURE; |
| 5125 | |
| 5126 | /* The ACL was happy */ |
| 5127 | |
| 5128 | if (rc == OK) |
| 5129 | { |
| 5130 | BOOL more = pipeline_response(); |
| 5131 | |
| 5132 | if (user_msg) |
| 5133 | smtp_user_msg(US"250", user_msg); |
| 5134 | else |
| 5135 | smtp_printf("250 Accepted\r\n", more); |
| 5136 | receive_add_recipient(recipient, -1); |
| 5137 | |
| 5138 | /* Set the dsn flags in the recipients_list */ |
| 5139 | recipients_list[recipients_count-1].orcpt = orcpt; |
| 5140 | recipients_list[recipients_count-1].dsn_flags = flags; |
| 5141 | |
| 5142 | DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n", |
| 5143 | recipients_list[recipients_count-1].orcpt, |
| 5144 | recipients_list[recipients_count-1].dsn_flags); |
| 5145 | } |
| 5146 | |
| 5147 | /* The recipient was discarded */ |
| 5148 | |
| 5149 | else if (rc == DISCARD) |
| 5150 | { |
| 5151 | if (user_msg) |
| 5152 | smtp_user_msg(US"250", user_msg); |
| 5153 | else |
| 5154 | smtp_printf("250 Accepted\r\n", FALSE); |
| 5155 | rcpt_fail_count++; |
| 5156 | discarded = TRUE; |
| 5157 | log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: " |
| 5158 | "discarded by %s ACL%s%s", host_and_ident(TRUE), |
| 5159 | sender_address_unrewritten? sender_address_unrewritten : sender_address, |
| 5160 | smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT", |
| 5161 | log_msg ? US": " : US"", log_msg ? log_msg : US""); |
| 5162 | } |
| 5163 | |
| 5164 | /* Either the ACL failed the address, or it was deferred. */ |
| 5165 | |
| 5166 | else |
| 5167 | { |
| 5168 | if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++; |
| 5169 | done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg); |
| 5170 | } |
| 5171 | break; |
| 5172 | |
| 5173 | |
| 5174 | /* The DATA command is legal only if it follows successful MAIL FROM |
| 5175 | and RCPT TO commands. However, if pipelining is advertised, a bad DATA is |
| 5176 | not counted as a protocol error if it follows RCPT (which must have been |
| 5177 | rejected if there are no recipients.) This function is complete when a |
| 5178 | valid DATA command is encountered. |
| 5179 | |
| 5180 | Note concerning the code used: RFC 2821 says this: |
| 5181 | |
| 5182 | - If there was no MAIL, or no RCPT, command, or all such commands |
| 5183 | were rejected, the server MAY return a "command out of sequence" |
| 5184 | (503) or "no valid recipients" (554) reply in response to the |
| 5185 | DATA command. |
| 5186 | |
| 5187 | The example in the pipelining RFC 2920 uses 554, but I use 503 here |
| 5188 | because it is the same whether pipelining is in use or not. |
| 5189 | |
| 5190 | If all the RCPT commands that precede DATA provoked the same error message |
| 5191 | (often indicating some kind of system error), it is helpful to include it |
| 5192 | with the DATA rejection (an idea suggested by Tony Finch). */ |
| 5193 | |
| 5194 | case BDAT_CMD: |
| 5195 | { |
| 5196 | int n; |
| 5197 | |
| 5198 | HAD(SCH_BDAT); |
| 5199 | if (chunking_state != CHUNKING_OFFERED) |
| 5200 | { |
| 5201 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 5202 | US"BDAT command used when CHUNKING not advertised"); |
| 5203 | break; |
| 5204 | } |
| 5205 | |
| 5206 | /* grab size, endmarker */ |
| 5207 | |
| 5208 | if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1) |
| 5209 | { |
| 5210 | done = synprot_error(L_smtp_protocol_error, 501, NULL, |
| 5211 | US"missing size for BDAT command"); |
| 5212 | break; |
| 5213 | } |
| 5214 | chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0 |
| 5215 | ? CHUNKING_LAST : CHUNKING_ACTIVE; |
| 5216 | chunking_data_left = chunking_datasize; |
| 5217 | DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n", |
| 5218 | (int)chunking_state, chunking_data_left); |
| 5219 | |
| 5220 | /* push the current receive_* function on the "stack", and |
| 5221 | replace them by bdat_getc(), which in turn will use the lwr_receive_* |
| 5222 | functions to do the dirty work. */ |
| 5223 | lwr_receive_getc = receive_getc; |
| 5224 | lwr_receive_getbuf = receive_getbuf; |
| 5225 | lwr_receive_ungetc = receive_ungetc; |
| 5226 | |
| 5227 | receive_getc = bdat_getc; |
| 5228 | receive_ungetc = bdat_ungetc; |
| 5229 | |
| 5230 | dot_ends = FALSE; |
| 5231 | |
| 5232 | goto DATA_BDAT; |
| 5233 | } |
| 5234 | |
| 5235 | case DATA_CMD: |
| 5236 | HAD(SCH_DATA); |
| 5237 | dot_ends = TRUE; |
| 5238 | |
| 5239 | DATA_BDAT: /* Common code for DATA and BDAT */ |
| 5240 | if (!discarded && recipients_count <= 0) |
| 5241 | { |
| 5242 | if (rcpt_smtp_response_same && rcpt_smtp_response != NULL) |
| 5243 | { |
| 5244 | uschar *code = US"503"; |
| 5245 | int len = Ustrlen(rcpt_smtp_response); |
| 5246 | smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with " |
| 5247 | "this error:"); |
| 5248 | /* Responses from smtp_printf() will have \r\n on the end */ |
| 5249 | if (len > 2 && rcpt_smtp_response[len-2] == '\r') |
| 5250 | rcpt_smtp_response[len-2] = 0; |
| 5251 | smtp_respond(code, 3, FALSE, rcpt_smtp_response); |
| 5252 | } |
| 5253 | if (smtp_in_pipelining_advertised && last_was_rcpt) |
| 5254 | smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE, |
| 5255 | smtp_names[smtp_connection_had[smtp_ch_index-1]]); |
| 5256 | else |
| 5257 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 5258 | smtp_connection_had[smtp_ch_index-1] == SCH_DATA |
| 5259 | ? US"valid RCPT command must precede DATA" |
| 5260 | : US"valid RCPT command must precede BDAT"); |
| 5261 | |
| 5262 | if (chunking_state > CHUNKING_OFFERED) |
| 5263 | bdat_flush_data(); |
| 5264 | break; |
| 5265 | } |
| 5266 | |
| 5267 | if (toomany && recipients_max_reject) |
| 5268 | { |
| 5269 | sender_address = NULL; /* This will allow a new MAIL without RSET */ |
| 5270 | sender_address_unrewritten = NULL; |
| 5271 | smtp_printf("554 Too many recipients\r\n", FALSE); |
| 5272 | break; |
| 5273 | } |
| 5274 | |
| 5275 | if (chunking_state > CHUNKING_OFFERED) |
| 5276 | rc = OK; /* No predata ACL or go-ahead output for BDAT */ |
| 5277 | else |
| 5278 | { |
| 5279 | /* If there is an ACL, re-check the synchronization afterwards, since the |
| 5280 | ACL may have delayed. To handle cutthrough delivery enforce a dummy call |
| 5281 | to get the DATA command sent. */ |
| 5282 | |
| 5283 | if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0) |
| 5284 | rc = OK; |
| 5285 | else |
| 5286 | { |
| 5287 | uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept"; |
| 5288 | enable_dollar_recipients = TRUE; |
| 5289 | rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg, |
| 5290 | &log_msg); |
| 5291 | enable_dollar_recipients = FALSE; |
| 5292 | if (rc == OK && !check_sync()) |
| 5293 | goto SYNC_FAILURE; |
| 5294 | |
| 5295 | if (rc != OK) |
| 5296 | { /* Either the ACL failed the address, or it was deferred. */ |
| 5297 | done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg); |
| 5298 | break; |
| 5299 | } |
| 5300 | } |
| 5301 | |
| 5302 | if (user_msg) |
| 5303 | smtp_user_msg(US"354", user_msg); |
| 5304 | else |
| 5305 | smtp_printf( |
| 5306 | "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE); |
| 5307 | } |
| 5308 | |
| 5309 | #ifdef TCP_QUICKACK |
| 5310 | if (smtp_in) /* all ACKs needed to ramp window up for bulk data */ |
| 5311 | (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK, |
| 5312 | US &on, sizeof(on)); |
| 5313 | #endif |
| 5314 | done = 3; |
| 5315 | message_ended = END_NOTENDED; /* Indicate in middle of data */ |
| 5316 | |
| 5317 | break; |
| 5318 | |
| 5319 | |
| 5320 | case VRFY_CMD: |
| 5321 | { |
| 5322 | uschar * address; |
| 5323 | |
| 5324 | HAD(SCH_VRFY); |
| 5325 | |
| 5326 | if (!(address = parse_extract_address(smtp_cmd_data, &errmess, |
| 5327 | &start, &end, &recipient_domain, FALSE))) |
| 5328 | { |
| 5329 | smtp_printf("501 %s\r\n", FALSE, errmess); |
| 5330 | break; |
| 5331 | } |
| 5332 | |
| 5333 | if (!recipient_domain) |
| 5334 | if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data, |
| 5335 | US"verify"))) |
| 5336 | break; |
| 5337 | |
| 5338 | if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy, |
| 5339 | &user_msg, &log_msg)) != OK) |
| 5340 | done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg); |
| 5341 | else |
| 5342 | { |
| 5343 | uschar * s = NULL; |
| 5344 | address_item * addr = deliver_make_addr(address, FALSE); |
| 5345 | |
| 5346 | switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1, |
| 5347 | -1, -1, NULL, NULL, NULL)) |
| 5348 | { |
| 5349 | case OK: |
| 5350 | s = string_sprintf("250 <%s> is deliverable", address); |
| 5351 | break; |
| 5352 | |
| 5353 | case DEFER: |
| 5354 | s = (addr->user_message != NULL)? |
| 5355 | string_sprintf("451 <%s> %s", address, addr->user_message) : |
| 5356 | string_sprintf("451 Cannot resolve <%s> at this time", address); |
| 5357 | break; |
| 5358 | |
| 5359 | case FAIL: |
| 5360 | s = (addr->user_message != NULL)? |
| 5361 | string_sprintf("550 <%s> %s", address, addr->user_message) : |
| 5362 | string_sprintf("550 <%s> is not deliverable", address); |
| 5363 | log_write(0, LOG_MAIN, "VRFY failed for %s %s", |
| 5364 | smtp_cmd_argument, host_and_ident(TRUE)); |
| 5365 | break; |
| 5366 | } |
| 5367 | |
| 5368 | smtp_printf("%s\r\n", FALSE, s); |
| 5369 | } |
| 5370 | break; |
| 5371 | } |
| 5372 | |
| 5373 | |
| 5374 | case EXPN_CMD: |
| 5375 | HAD(SCH_EXPN); |
| 5376 | rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg); |
| 5377 | if (rc != OK) |
| 5378 | done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg); |
| 5379 | else |
| 5380 | { |
| 5381 | BOOL save_log_testing_mode = log_testing_mode; |
| 5382 | address_test_mode = log_testing_mode = TRUE; |
| 5383 | (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE), |
| 5384 | smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1, |
| 5385 | NULL, NULL, NULL); |
| 5386 | address_test_mode = FALSE; |
| 5387 | log_testing_mode = save_log_testing_mode; /* true for -bh */ |
| 5388 | } |
| 5389 | break; |
| 5390 | |
| 5391 | |
| 5392 | #ifdef SUPPORT_TLS |
| 5393 | |
| 5394 | case STARTTLS_CMD: |
| 5395 | HAD(SCH_STARTTLS); |
| 5396 | if (!tls_advertised) |
| 5397 | { |
| 5398 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 5399 | US"STARTTLS command used when not advertised"); |
| 5400 | break; |
| 5401 | } |
| 5402 | |
| 5403 | /* Apply an ACL check if one is defined */ |
| 5404 | |
| 5405 | if ( acl_smtp_starttls |
| 5406 | && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, |
| 5407 | &user_msg, &log_msg)) != OK |
| 5408 | ) |
| 5409 | { |
| 5410 | done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg); |
| 5411 | break; |
| 5412 | } |
| 5413 | |
| 5414 | /* RFC 2487 is not clear on when this command may be sent, though it |
| 5415 | does state that all information previously obtained from the client |
| 5416 | must be discarded if a TLS session is started. It seems reasonable to |
| 5417 | do an implied RSET when STARTTLS is received. */ |
| 5418 | |
| 5419 | incomplete_transaction_log(US"STARTTLS"); |
| 5420 | cancel_cutthrough_connection(TRUE, US"STARTTLS received"); |
| 5421 | smtp_reset(reset_point); |
| 5422 | toomany = FALSE; |
| 5423 | cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE; |
| 5424 | |
| 5425 | /* There's an attack where more data is read in past the STARTTLS command |
| 5426 | before TLS is negotiated, then assumed to be part of the secure session |
| 5427 | when used afterwards; we use segregated input buffers, so are not |
| 5428 | vulnerable, but we want to note when it happens and, for sheer paranoia, |
| 5429 | ensure that the buffer is "wiped". |
| 5430 | Pipelining sync checks will normally have protected us too, unless disabled |
| 5431 | by configuration. */ |
| 5432 | |
| 5433 | if (receive_smtp_buffered()) |
| 5434 | { |
| 5435 | DEBUG(D_any) |
| 5436 | debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n"); |
| 5437 | if (tls_in.active.sock < 0) |
| 5438 | smtp_inend = smtp_inptr = smtp_inbuffer; |
| 5439 | /* and if TLS is already active, tls_server_start() should fail */ |
| 5440 | } |
| 5441 | |
| 5442 | /* There is nothing we value in the input buffer and if TLS is successfully |
| 5443 | negotiated, we won't use this buffer again; if TLS fails, we'll just read |
| 5444 | fresh content into it. The buffer contains arbitrary content from an |
| 5445 | untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n |
| 5446 | It seems safest to just wipe away the content rather than leave it as a |
| 5447 | target to jump to. */ |
| 5448 | |
| 5449 | memset(smtp_inbuffer, 0, IN_BUFFER_SIZE); |
| 5450 | |
| 5451 | /* Attempt to start up a TLS session, and if successful, discard all |
| 5452 | knowledge that was obtained previously. At least, that's what the RFC says, |
| 5453 | and that's what happens by default. However, in order to work round YAEB, |
| 5454 | there is an option to remember the esmtp state. Sigh. |
| 5455 | |
| 5456 | We must allow for an extra EHLO command and an extra AUTH command after |
| 5457 | STARTTLS that don't add to the nonmail command count. */ |
| 5458 | |
| 5459 | s = NULL; |
| 5460 | if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK) |
| 5461 | { |
| 5462 | if (!tls_remember_esmtp) |
| 5463 | helo_seen = esmtp = auth_advertised = smtp_in_pipelining_advertised = FALSE; |
| 5464 | cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE; |
| 5465 | cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE; |
| 5466 | cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE; |
| 5467 | if (sender_helo_name) |
| 5468 | { |
| 5469 | store_free(sender_helo_name); |
| 5470 | sender_helo_name = NULL; |
| 5471 | host_build_sender_fullhost(); /* Rebuild */ |
| 5472 | set_process_info("handling incoming TLS connection from %s", |
| 5473 | host_and_ident(FALSE)); |
| 5474 | } |
| 5475 | received_protocol = |
| 5476 | (sender_host_address ? protocols : protocols_local) |
| 5477 | [ (esmtp |
| 5478 | ? pextend + (sender_host_authenticated ? pauthed : 0) |
| 5479 | : pnormal) |
| 5480 | + (tls_in.active.sock >= 0 ? pcrpted : 0) |
| 5481 | ]; |
| 5482 | |
| 5483 | sender_host_auth_pubname = sender_host_authenticated = NULL; |
| 5484 | authenticated_id = NULL; |
| 5485 | sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING; |
| 5486 | DEBUG(D_tls) debug_printf("TLS active\n"); |
| 5487 | break; /* Successful STARTTLS */ |
| 5488 | } |
| 5489 | else |
| 5490 | (void) smtp_log_tls_fail(s); |
| 5491 | |
| 5492 | /* Some local configuration problem was discovered before actually trying |
| 5493 | to do a TLS handshake; give a temporary error. */ |
| 5494 | |
| 5495 | if (rc == DEFER) |
| 5496 | { |
| 5497 | smtp_printf("454 TLS currently unavailable\r\n", FALSE); |
| 5498 | break; |
| 5499 | } |
| 5500 | |
| 5501 | /* Hard failure. Reject everything except QUIT or closed connection. One |
| 5502 | cause for failure is a nested STARTTLS, in which case tls_in.active remains |
| 5503 | set, but we must still reject all incoming commands. */ |
| 5504 | |
| 5505 | DEBUG(D_tls) debug_printf("TLS failed to start\n"); |
| 5506 | while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED)) |
| 5507 | { |
| 5508 | case EOF_CMD: |
| 5509 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF", |
| 5510 | smtp_get_connection_info()); |
| 5511 | smtp_notquit_exit(US"tls-failed", NULL, NULL); |
| 5512 | done = 2; |
| 5513 | break; |
| 5514 | |
| 5515 | /* It is perhaps arguable as to which exit ACL should be called here, |
| 5516 | but as it is probably a situation that almost never arises, it |
| 5517 | probably doesn't matter. We choose to call the real QUIT ACL, which in |
| 5518 | some sense is perhaps "right". */ |
| 5519 | |
| 5520 | case QUIT_CMD: |
| 5521 | user_msg = NULL; |
| 5522 | if ( acl_smtp_quit |
| 5523 | && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, |
| 5524 | &log_msg)) == ERROR)) |
| 5525 | log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s", |
| 5526 | log_msg); |
| 5527 | if (user_msg) |
| 5528 | smtp_respond(US"221", 3, TRUE, user_msg); |
| 5529 | else |
| 5530 | smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname); |
| 5531 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT", |
| 5532 | smtp_get_connection_info()); |
| 5533 | done = 2; |
| 5534 | break; |
| 5535 | |
| 5536 | default: |
| 5537 | smtp_printf("554 Security failure\r\n", FALSE); |
| 5538 | break; |
| 5539 | } |
| 5540 | tls_close(NULL, TLS_SHUTDOWN_NOWAIT); |
| 5541 | break; |
| 5542 | #endif |
| 5543 | |
| 5544 | |
| 5545 | /* The ACL for QUIT is provided for gathering statistical information or |
| 5546 | similar; it does not affect the response code, but it can supply a custom |
| 5547 | message. */ |
| 5548 | |
| 5549 | case QUIT_CMD: |
| 5550 | smtp_quit_handler(&user_msg, &log_msg); |
| 5551 | done = 2; |
| 5552 | break; |
| 5553 | |
| 5554 | |
| 5555 | case RSET_CMD: |
| 5556 | smtp_rset_handler(); |
| 5557 | cancel_cutthrough_connection(TRUE, US"RSET received"); |
| 5558 | smtp_reset(reset_point); |
| 5559 | toomany = FALSE; |
| 5560 | break; |
| 5561 | |
| 5562 | |
| 5563 | case NOOP_CMD: |
| 5564 | HAD(SCH_NOOP); |
| 5565 | smtp_printf("250 OK\r\n", FALSE); |
| 5566 | break; |
| 5567 | |
| 5568 | |
| 5569 | /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually |
| 5570 | used, a check will be done for permitted hosts. Show STARTTLS only if not |
| 5571 | already in a TLS session and if it would be advertised in the EHLO |
| 5572 | response. */ |
| 5573 | |
| 5574 | case HELP_CMD: |
| 5575 | HAD(SCH_HELP); |
| 5576 | smtp_printf("214-Commands supported:\r\n", TRUE); |
| 5577 | { |
| 5578 | uschar buffer[256]; |
| 5579 | buffer[0] = 0; |
| 5580 | Ustrcat(buffer, " AUTH"); |
| 5581 | #ifdef SUPPORT_TLS |
| 5582 | if (tls_in.active.sock < 0 && |
| 5583 | verify_check_host(&tls_advertise_hosts) != FAIL) |
| 5584 | Ustrcat(buffer, " STARTTLS"); |
| 5585 | #endif |
| 5586 | Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT"); |
| 5587 | Ustrcat(buffer, " NOOP QUIT RSET HELP"); |
| 5588 | if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN"); |
| 5589 | if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN"); |
| 5590 | if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY"); |
| 5591 | smtp_printf("214%s\r\n", FALSE, buffer); |
| 5592 | } |
| 5593 | break; |
| 5594 | |
| 5595 | |
| 5596 | case EOF_CMD: |
| 5597 | incomplete_transaction_log(US"connection lost"); |
| 5598 | smtp_notquit_exit(US"connection-lost", US"421", |
| 5599 | US"%s lost input connection", smtp_active_hostname); |
| 5600 | |
| 5601 | /* Don't log by default unless in the middle of a message, as some mailers |
| 5602 | just drop the call rather than sending QUIT, and it clutters up the logs. |
| 5603 | */ |
| 5604 | |
| 5605 | if (sender_address || recipients_count > 0) |
| 5606 | log_write(L_lost_incoming_connection, LOG_MAIN, |
| 5607 | "unexpected %s while reading SMTP command from %s%s%s D=%s", |
| 5608 | sender_host_unknown ? "EOF" : "disconnection", |
| 5609 | tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"", |
| 5610 | host_and_ident(FALSE), smtp_read_error, |
| 5611 | string_timesince(&smtp_connection_start) |
| 5612 | ); |
| 5613 | |
| 5614 | else |
| 5615 | log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s", |
| 5616 | smtp_get_connection_info(), |
| 5617 | tcp_in_fastopen && !tcp_in_fastopen_logged ? US"TFO " : US"", |
| 5618 | smtp_read_error, |
| 5619 | string_timesince(&smtp_connection_start) |
| 5620 | ); |
| 5621 | |
| 5622 | done = 1; |
| 5623 | break; |
| 5624 | |
| 5625 | |
| 5626 | case ETRN_CMD: |
| 5627 | HAD(SCH_ETRN); |
| 5628 | if (sender_address) |
| 5629 | { |
| 5630 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 5631 | US"ETRN is not permitted inside a transaction"); |
| 5632 | break; |
| 5633 | } |
| 5634 | |
| 5635 | log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument, |
| 5636 | host_and_ident(FALSE)); |
| 5637 | |
| 5638 | if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, |
| 5639 | &user_msg, &log_msg)) != OK) |
| 5640 | { |
| 5641 | done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg); |
| 5642 | break; |
| 5643 | } |
| 5644 | |
| 5645 | /* Compute the serialization key for this command. */ |
| 5646 | |
| 5647 | etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data); |
| 5648 | |
| 5649 | /* If a command has been specified for running as a result of ETRN, we |
| 5650 | permit any argument to ETRN. If not, only the # standard form is permitted, |
| 5651 | since that is strictly the only kind of ETRN that can be implemented |
| 5652 | according to the RFC. */ |
| 5653 | |
| 5654 | if (smtp_etrn_command) |
| 5655 | { |
| 5656 | uschar *error; |
| 5657 | BOOL rc; |
| 5658 | etrn_command = smtp_etrn_command; |
| 5659 | deliver_domain = smtp_cmd_data; |
| 5660 | rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL, |
| 5661 | US"ETRN processing", &error); |
| 5662 | deliver_domain = NULL; |
| 5663 | if (!rc) |
| 5664 | { |
| 5665 | log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s", |
| 5666 | error); |
| 5667 | smtp_printf("458 Internal failure\r\n", FALSE); |
| 5668 | break; |
| 5669 | } |
| 5670 | } |
| 5671 | |
| 5672 | /* Else set up to call Exim with the -R option. */ |
| 5673 | |
| 5674 | else |
| 5675 | { |
| 5676 | if (*smtp_cmd_data++ != '#') |
| 5677 | { |
| 5678 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 5679 | US"argument must begin with #"); |
| 5680 | break; |
| 5681 | } |
| 5682 | etrn_command = US"exim -R"; |
| 5683 | argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, |
| 5684 | *queue_name ? 4 : 2, |
| 5685 | US"-R", smtp_cmd_data, |
| 5686 | US"-MCG", queue_name); |
| 5687 | } |
| 5688 | |
| 5689 | /* If we are host-testing, don't actually do anything. */ |
| 5690 | |
| 5691 | if (host_checking) |
| 5692 | { |
| 5693 | HDEBUG(D_any) |
| 5694 | { |
| 5695 | debug_printf("ETRN command is: %s\n", etrn_command); |
| 5696 | debug_printf("ETRN command execution skipped\n"); |
| 5697 | } |
| 5698 | if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE); |
| 5699 | else smtp_user_msg(US"250", user_msg); |
| 5700 | break; |
| 5701 | } |
| 5702 | |
| 5703 | |
| 5704 | /* If ETRN queue runs are to be serialized, check the database to |
| 5705 | ensure one isn't already running. */ |
| 5706 | |
| 5707 | if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1)) |
| 5708 | { |
| 5709 | smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data); |
| 5710 | break; |
| 5711 | } |
| 5712 | |
| 5713 | /* Fork a child process and run the command. We don't want to have to |
| 5714 | wait for the process at any point, so set SIGCHLD to SIG_IGN before |
| 5715 | forking. It should be set that way anyway for external incoming SMTP, |
| 5716 | but we save and restore to be tidy. If serialization is required, we |
| 5717 | actually run the command in yet another process, so we can wait for it |
| 5718 | to complete and then remove the serialization lock. */ |
| 5719 | |
| 5720 | oldsignal = signal(SIGCHLD, SIG_IGN); |
| 5721 | |
| 5722 | if ((pid = fork()) == 0) |
| 5723 | { |
| 5724 | smtp_input = FALSE; /* This process is not associated with the */ |
| 5725 | (void)fclose(smtp_in); /* SMTP call any more. */ |
| 5726 | (void)fclose(smtp_out); |
| 5727 | |
| 5728 | signal(SIGCHLD, SIG_DFL); /* Want to catch child */ |
| 5729 | |
| 5730 | /* If not serializing, do the exec right away. Otherwise, fork down |
| 5731 | into another process. */ |
| 5732 | |
| 5733 | if (!smtp_etrn_serialize || (pid = fork()) == 0) |
| 5734 | { |
| 5735 | DEBUG(D_exec) debug_print_argv(argv); |
| 5736 | exim_nullstd(); /* Ensure std{in,out,err} exist */ |
| 5737 | execv(CS argv[0], (char *const *)argv); |
| 5738 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s", |
| 5739 | etrn_command, strerror(errno)); |
| 5740 | _exit(EXIT_FAILURE); /* paranoia */ |
| 5741 | } |
| 5742 | |
| 5743 | /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That |
| 5744 | is, we are in the first subprocess, after forking again. All we can do |
| 5745 | for a failing fork is to log it. Otherwise, wait for the 2nd process to |
| 5746 | complete, before removing the serialization. */ |
| 5747 | |
| 5748 | if (pid < 0) |
| 5749 | log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN " |
| 5750 | "failed: %s", strerror(errno)); |
| 5751 | else |
| 5752 | { |
| 5753 | int status; |
| 5754 | DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n", |
| 5755 | (int)pid); |
| 5756 | (void)wait(&status); |
| 5757 | DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n", |
| 5758 | (int)pid); |
| 5759 | } |
| 5760 | |
| 5761 | enq_end(etrn_serialize_key); |
| 5762 | _exit(EXIT_SUCCESS); |
| 5763 | } |
| 5764 | |
| 5765 | /* Back in the top level SMTP process. Check that we started a subprocess |
| 5766 | and restore the signal state. */ |
| 5767 | |
| 5768 | if (pid < 0) |
| 5769 | { |
| 5770 | log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s", |
| 5771 | strerror(errno)); |
| 5772 | smtp_printf("458 Unable to fork process\r\n", FALSE); |
| 5773 | if (smtp_etrn_serialize) enq_end(etrn_serialize_key); |
| 5774 | } |
| 5775 | else |
| 5776 | { |
| 5777 | if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE); |
| 5778 | else smtp_user_msg(US"250", user_msg); |
| 5779 | } |
| 5780 | |
| 5781 | signal(SIGCHLD, oldsignal); |
| 5782 | break; |
| 5783 | |
| 5784 | |
| 5785 | case BADARG_CMD: |
| 5786 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 5787 | US"unexpected argument data"); |
| 5788 | break; |
| 5789 | |
| 5790 | |
| 5791 | /* This currently happens only for NULLs, but could be extended. */ |
| 5792 | |
| 5793 | case BADCHAR_CMD: |
| 5794 | done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */ |
| 5795 | US"NUL character(s) present (shown as '?')"); |
| 5796 | smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n", |
| 5797 | FALSE); |
| 5798 | break; |
| 5799 | |
| 5800 | |
| 5801 | case BADSYN_CMD: |
| 5802 | SYNC_FAILURE: |
| 5803 | if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE) |
| 5804 | smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1; |
| 5805 | c = smtp_inend - smtp_inptr; |
| 5806 | if (c > 150) c = 150; /* limit logged amount */ |
| 5807 | smtp_inptr[c] = 0; |
| 5808 | incomplete_transaction_log(US"sync failure"); |
| 5809 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error " |
| 5810 | "(next input sent too soon: pipelining was%s advertised): " |
| 5811 | "rejected \"%s\" %s next input=\"%s\"", |
| 5812 | smtp_in_pipelining_advertised ? "" : " not", |
| 5813 | smtp_cmd_buffer, host_and_ident(TRUE), |
| 5814 | string_printing(smtp_inptr)); |
| 5815 | smtp_notquit_exit(US"synchronization-error", US"554", |
| 5816 | US"SMTP synchronization error"); |
| 5817 | done = 1; /* Pretend eof - drops connection */ |
| 5818 | break; |
| 5819 | |
| 5820 | |
| 5821 | case TOO_MANY_NONMAIL_CMD: |
| 5822 | s = smtp_cmd_buffer; |
| 5823 | while (*s != 0 && !isspace(*s)) s++; |
| 5824 | incomplete_transaction_log(US"too many non-mail commands"); |
| 5825 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " |
| 5826 | "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE), |
| 5827 | (int)(s - smtp_cmd_buffer), smtp_cmd_buffer); |
| 5828 | smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands"); |
| 5829 | done = 1; /* Pretend eof - drops connection */ |
| 5830 | break; |
| 5831 | |
| 5832 | #ifdef SUPPORT_PROXY |
| 5833 | case PROXY_FAIL_IGNORE_CMD: |
| 5834 | smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE); |
| 5835 | break; |
| 5836 | #endif |
| 5837 | |
| 5838 | default: |
| 5839 | if (unknown_command_count++ >= smtp_max_unknown_commands) |
| 5840 | { |
| 5841 | log_write(L_smtp_syntax_error, LOG_MAIN, |
| 5842 | "SMTP syntax error in \"%s\" %s %s", |
| 5843 | string_printing(smtp_cmd_buffer), host_and_ident(TRUE), |
| 5844 | US"unrecognized command"); |
| 5845 | incomplete_transaction_log(US"unrecognized command"); |
| 5846 | smtp_notquit_exit(US"bad-commands", US"500", |
| 5847 | US"Too many unrecognized commands"); |
| 5848 | done = 2; |
| 5849 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " |
| 5850 | "unrecognized commands (last was \"%s\")", host_and_ident(FALSE), |
| 5851 | string_printing(smtp_cmd_buffer)); |
| 5852 | } |
| 5853 | else |
| 5854 | done = synprot_error(L_smtp_syntax_error, 500, NULL, |
| 5855 | US"unrecognized command"); |
| 5856 | break; |
| 5857 | } |
| 5858 | |
| 5859 | /* This label is used by goto's inside loops that want to break out to |
| 5860 | the end of the command-processing loop. */ |
| 5861 | |
| 5862 | COMMAND_LOOP: |
| 5863 | last_was_rej_mail = was_rej_mail; /* Remember some last commands for */ |
| 5864 | last_was_rcpt = was_rcpt; /* protocol error handling */ |
| 5865 | continue; |
| 5866 | } |
| 5867 | |
| 5868 | return done - 2; /* Convert yield values */ |
| 5869 | } |
| 5870 | |
| 5871 | |
| 5872 | |
| 5873 | gstring * |
| 5874 | authres_smtpauth(gstring * g) |
| 5875 | { |
| 5876 | if (!sender_host_authenticated) |
| 5877 | return g; |
| 5878 | |
| 5879 | g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname); |
| 5880 | |
| 5881 | if (Ustrcmp(sender_host_auth_pubname, "tls") != 0) |
| 5882 | g = string_append(g, 2, US") smtp.auth=", authenticated_id); |
| 5883 | else if (authenticated_id) |
| 5884 | g = string_append(g, 2, US") x509.auth=", authenticated_id); |
| 5885 | else |
| 5886 | g = string_catn(g, US") reason=x509.auth", 17); |
| 5887 | |
| 5888 | if (authenticated_sender) |
| 5889 | g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender); |
| 5890 | return g; |
| 5891 | } |
| 5892 | |
| 5893 | |
| 5894 | |
| 5895 | /* vi: aw ai sw=2 |
| 5896 | */ |
| 5897 | /* End of smtp_in.c */ |