| 1 | /************************************************* |
| 2 | * Exim - an Internet mail transport agent * |
| 3 | *************************************************/ |
| 4 | |
| 5 | /* Copyright (c) University of Cambridge 1995 - 2012 */ |
| 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 | |
| 13 | |
| 14 | /* Initialize for TCP wrappers if so configured. It appears that the macro |
| 15 | HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before |
| 16 | including that header, and restore its value afterwards. */ |
| 17 | |
| 18 | #ifdef USE_TCP_WRAPPERS |
| 19 | |
| 20 | #if HAVE_IPV6 |
| 21 | #define EXIM_HAVE_IPV6 |
| 22 | #endif |
| 23 | #undef HAVE_IPV6 |
| 24 | #include <tcpd.h> |
| 25 | #undef HAVE_IPV6 |
| 26 | #ifdef EXIM_HAVE_IPV6 |
| 27 | #define HAVE_IPV6 TRUE |
| 28 | #endif |
| 29 | |
| 30 | int allow_severity = LOG_INFO; |
| 31 | int deny_severity = LOG_NOTICE; |
| 32 | uschar *tcp_wrappers_name; |
| 33 | #endif |
| 34 | |
| 35 | |
| 36 | /* Size of buffer for reading SMTP commands. We used to use 512, as defined |
| 37 | by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP |
| 38 | commands that accept arguments, and this in particular applies to AUTH, where |
| 39 | the data can be quite long. More recently this value was 2048 in Exim; |
| 40 | however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients |
| 41 | such as Thunderbird will send an AUTH with an initial-response for GSSAPI. |
| 42 | The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and |
| 43 | we need room to handle large base64-encoded AUTHs for GSSAPI. |
| 44 | */ |
| 45 | |
| 46 | #define smtp_cmd_buffer_size 16384 |
| 47 | |
| 48 | /* Size of buffer for reading SMTP incoming packets */ |
| 49 | |
| 50 | #define in_buffer_size 8192 |
| 51 | |
| 52 | /* Structure for SMTP command list */ |
| 53 | |
| 54 | typedef struct { |
| 55 | const char *name; |
| 56 | int len; |
| 57 | short int cmd; |
| 58 | short int has_arg; |
| 59 | short int is_mail_cmd; |
| 60 | } smtp_cmd_list; |
| 61 | |
| 62 | /* Codes for identifying commands. We order them so that those that come first |
| 63 | are those for which synchronization is always required. Checking this can help |
| 64 | block some spam. */ |
| 65 | |
| 66 | enum { |
| 67 | /* These commands are required to be synchronized, i.e. to be the last in a |
| 68 | block of commands when pipelining. */ |
| 69 | |
| 70 | HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */ |
| 71 | VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */ |
| 72 | ETRN_CMD, /* This by analogy with TURN from the RFC */ |
| 73 | STARTTLS_CMD, /* Required by the STARTTLS RFC */ |
| 74 | |
| 75 | /* This is a dummy to identify the non-sync commands when pipelining */ |
| 76 | |
| 77 | NON_SYNC_CMD_PIPELINING, |
| 78 | |
| 79 | /* These commands need not be synchronized when pipelining */ |
| 80 | |
| 81 | MAIL_CMD, RCPT_CMD, RSET_CMD, |
| 82 | |
| 83 | /* This is a dummy to identify the non-sync commands when not pipelining */ |
| 84 | |
| 85 | NON_SYNC_CMD_NON_PIPELINING, |
| 86 | |
| 87 | /* I have been unable to find a statement about the use of pipelining |
| 88 | with AUTH, so to be on the safe side it is here, though I kind of feel |
| 89 | it should be up there with the synchronized commands. */ |
| 90 | |
| 91 | AUTH_CMD, |
| 92 | |
| 93 | /* I'm not sure about these, but I don't think they matter. */ |
| 94 | |
| 95 | QUIT_CMD, HELP_CMD, |
| 96 | |
| 97 | /* These are specials that don't correspond to actual commands */ |
| 98 | |
| 99 | EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD, |
| 100 | TOO_MANY_NONMAIL_CMD }; |
| 101 | |
| 102 | |
| 103 | /* This is a convenience macro for adding the identity of an SMTP command |
| 104 | to the circular buffer that holds a list of the last n received. */ |
| 105 | |
| 106 | #define HAD(n) \ |
| 107 | smtp_connection_had[smtp_ch_index++] = n; \ |
| 108 | if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0 |
| 109 | |
| 110 | |
| 111 | /************************************************* |
| 112 | * Local static variables * |
| 113 | *************************************************/ |
| 114 | |
| 115 | static auth_instance *authenticated_by; |
| 116 | static BOOL auth_advertised; |
| 117 | #ifdef SUPPORT_TLS |
| 118 | static BOOL tls_advertised; |
| 119 | #endif |
| 120 | static BOOL esmtp; |
| 121 | static BOOL helo_required = FALSE; |
| 122 | static BOOL helo_verify = FALSE; |
| 123 | static BOOL helo_seen; |
| 124 | static BOOL helo_accept_junk; |
| 125 | static BOOL count_nonmail; |
| 126 | static BOOL pipelining_advertised; |
| 127 | static BOOL rcpt_smtp_response_same; |
| 128 | static BOOL rcpt_in_progress; |
| 129 | static int nonmail_command_count; |
| 130 | static BOOL smtp_exit_function_called = 0; |
| 131 | static int synprot_error_count; |
| 132 | static int unknown_command_count; |
| 133 | static int sync_cmd_limit; |
| 134 | static int smtp_write_error = 0; |
| 135 | |
| 136 | static uschar *rcpt_smtp_response; |
| 137 | static uschar *smtp_data_buffer; |
| 138 | static uschar *smtp_cmd_data; |
| 139 | |
| 140 | /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their |
| 141 | final fields of all except AUTH are forced TRUE at the start of a new message |
| 142 | setup, to allow one of each between messages that is not counted as a nonmail |
| 143 | command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to |
| 144 | allow a new EHLO after starting up TLS. |
| 145 | |
| 146 | AUTH is "falsely" labelled as a mail command initially, so that it doesn't get |
| 147 | counted. However, the flag is changed when AUTH is received, so that multiple |
| 148 | failing AUTHs will eventually hit the limit. After a successful AUTH, another |
| 149 | AUTH is already forbidden. After a TLS session is started, AUTH's flag is again |
| 150 | forced TRUE, to allow for the re-authentication that can happen at that point. |
| 151 | |
| 152 | QUIT is also "falsely" labelled as a mail command so that it doesn't up the |
| 153 | count of non-mail commands and possibly provoke an error. */ |
| 154 | |
| 155 | static smtp_cmd_list cmd_list[] = { |
| 156 | { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */ |
| 157 | { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE }, |
| 158 | { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE }, |
| 159 | { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE }, |
| 160 | #ifdef SUPPORT_TLS |
| 161 | { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE }, |
| 162 | #endif |
| 163 | |
| 164 | /* If you change anything above here, also fix the definitions below. */ |
| 165 | |
| 166 | { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE }, |
| 167 | { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE }, |
| 168 | { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE }, |
| 169 | { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE }, |
| 170 | { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE }, |
| 171 | { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE }, |
| 172 | { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE }, |
| 173 | { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE }, |
| 174 | { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE } |
| 175 | }; |
| 176 | |
| 177 | static smtp_cmd_list *cmd_list_end = |
| 178 | cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list); |
| 179 | |
| 180 | #define CMD_LIST_RSET 0 |
| 181 | #define CMD_LIST_HELO 1 |
| 182 | #define CMD_LIST_EHLO 2 |
| 183 | #define CMD_LIST_AUTH 3 |
| 184 | #define CMD_LIST_STARTTLS 4 |
| 185 | |
| 186 | /* This list of names is used for performing the smtp_no_mail logging action. |
| 187 | It must be kept in step with the SCH_xxx enumerations. */ |
| 188 | |
| 189 | static uschar *smtp_names[] = |
| 190 | { |
| 191 | US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO", |
| 192 | US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS", |
| 193 | US"VRFY" }; |
| 194 | |
| 195 | static uschar *protocols[] = { |
| 196 | US"local-smtp", /* HELO */ |
| 197 | US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */ |
| 198 | US"local-esmtp", /* EHLO */ |
| 199 | US"local-esmtps", /* EHLO->STARTTLS->EHLO */ |
| 200 | US"local-esmtpa", /* EHLO->AUTH */ |
| 201 | US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */ |
| 202 | }; |
| 203 | |
| 204 | #define pnormal 0 |
| 205 | #define pextend 2 |
| 206 | #define pcrpted 1 /* added to pextend or pnormal */ |
| 207 | #define pauthed 2 /* added to pextend */ |
| 208 | #define pnlocal 6 /* offset to remove "local" */ |
| 209 | |
| 210 | /* Sanity check and validate optional args to MAIL FROM: envelope */ |
| 211 | enum { |
| 212 | ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH, |
| 213 | ENV_MAIL_OPT_PRDR, ENV_MAIL_OPT_NULL |
| 214 | }; |
| 215 | typedef struct { |
| 216 | uschar * name; /* option requested during MAIL cmd */ |
| 217 | int value; /* enum type */ |
| 218 | BOOL need_value; /* TRUE requires value (name=value pair format) |
| 219 | FALSE is a singleton */ |
| 220 | } env_mail_type_t; |
| 221 | static env_mail_type_t env_mail_type_list[] = { |
| 222 | { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE }, |
| 223 | { US"BODY", ENV_MAIL_OPT_BODY, TRUE }, |
| 224 | { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE }, |
| 225 | { US"NULL", ENV_MAIL_OPT_NULL, FALSE } /* Placeholder for ending */ |
| 226 | }; |
| 227 | |
| 228 | /* When reading SMTP from a remote host, we have to use our own versions of the |
| 229 | C input-reading functions, in order to be able to flush the SMTP output only |
| 230 | when about to read more data from the socket. This is the only way to get |
| 231 | optimal performance when the client is using pipelining. Flushing for every |
| 232 | command causes a separate packet and reply packet each time; saving all the |
| 233 | responses up (when pipelining) combines them into one packet and one response. |
| 234 | |
| 235 | For simplicity, these functions are used for *all* SMTP input, not only when |
| 236 | receiving over a socket. However, after setting up a secure socket (SSL), input |
| 237 | is read via the OpenSSL library, and another set of functions is used instead |
| 238 | (see tls.c). |
| 239 | |
| 240 | These functions are set in the receive_getc etc. variables and called with the |
| 241 | same interface as the C functions. However, since there can only ever be |
| 242 | one incoming SMTP call, we just use a single buffer and flags. There is no need |
| 243 | to implement a complicated private FILE-like structure.*/ |
| 244 | |
| 245 | static uschar *smtp_inbuffer; |
| 246 | static uschar *smtp_inptr; |
| 247 | static uschar *smtp_inend; |
| 248 | static int smtp_had_eof; |
| 249 | static int smtp_had_error; |
| 250 | |
| 251 | |
| 252 | /************************************************* |
| 253 | * SMTP version of getc() * |
| 254 | *************************************************/ |
| 255 | |
| 256 | /* This gets the next byte from the SMTP input buffer. If the buffer is empty, |
| 257 | it flushes the output, and refills the buffer, with a timeout. The signal |
| 258 | handler is set appropriately by the calling function. This function is not used |
| 259 | after a connection has negotated itself into an TLS/SSL state. |
| 260 | |
| 261 | Arguments: none |
| 262 | Returns: the next character or EOF |
| 263 | */ |
| 264 | |
| 265 | int |
| 266 | smtp_getc(void) |
| 267 | { |
| 268 | if (smtp_inptr >= smtp_inend) |
| 269 | { |
| 270 | int rc, save_errno; |
| 271 | fflush(smtp_out); |
| 272 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); |
| 273 | rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size); |
| 274 | save_errno = errno; |
| 275 | alarm(0); |
| 276 | if (rc <= 0) |
| 277 | { |
| 278 | /* Must put the error text in fixed store, because this might be during |
| 279 | header reading, where it releases unused store above the header. */ |
| 280 | if (rc < 0) |
| 281 | { |
| 282 | smtp_had_error = save_errno; |
| 283 | smtp_read_error = string_copy_malloc( |
| 284 | string_sprintf(" (error: %s)", strerror(save_errno))); |
| 285 | } |
| 286 | else smtp_had_eof = 1; |
| 287 | return EOF; |
| 288 | } |
| 289 | #ifndef DISABLE_DKIM |
| 290 | dkim_exim_verify_feed(smtp_inbuffer, rc); |
| 291 | #endif |
| 292 | smtp_inend = smtp_inbuffer + rc; |
| 293 | smtp_inptr = smtp_inbuffer; |
| 294 | } |
| 295 | return *smtp_inptr++; |
| 296 | } |
| 297 | |
| 298 | |
| 299 | |
| 300 | /************************************************* |
| 301 | * SMTP version of ungetc() * |
| 302 | *************************************************/ |
| 303 | |
| 304 | /* Puts a character back in the input buffer. Only ever |
| 305 | called once. |
| 306 | |
| 307 | Arguments: |
| 308 | ch the character |
| 309 | |
| 310 | Returns: the character |
| 311 | */ |
| 312 | |
| 313 | int |
| 314 | smtp_ungetc(int ch) |
| 315 | { |
| 316 | *(--smtp_inptr) = ch; |
| 317 | return ch; |
| 318 | } |
| 319 | |
| 320 | |
| 321 | |
| 322 | |
| 323 | /************************************************* |
| 324 | * SMTP version of feof() * |
| 325 | *************************************************/ |
| 326 | |
| 327 | /* Tests for a previous EOF |
| 328 | |
| 329 | Arguments: none |
| 330 | Returns: non-zero if the eof flag is set |
| 331 | */ |
| 332 | |
| 333 | int |
| 334 | smtp_feof(void) |
| 335 | { |
| 336 | return smtp_had_eof; |
| 337 | } |
| 338 | |
| 339 | |
| 340 | |
| 341 | |
| 342 | /************************************************* |
| 343 | * SMTP version of ferror() * |
| 344 | *************************************************/ |
| 345 | |
| 346 | /* Tests for a previous read error, and returns with errno |
| 347 | restored to what it was when the error was detected. |
| 348 | |
| 349 | Arguments: none |
| 350 | Returns: non-zero if the error flag is set |
| 351 | */ |
| 352 | |
| 353 | int |
| 354 | smtp_ferror(void) |
| 355 | { |
| 356 | errno = smtp_had_error; |
| 357 | return smtp_had_error; |
| 358 | } |
| 359 | |
| 360 | |
| 361 | |
| 362 | /************************************************* |
| 363 | * Test for characters in the SMTP buffer * |
| 364 | *************************************************/ |
| 365 | |
| 366 | /* Used at the end of a message |
| 367 | |
| 368 | Arguments: none |
| 369 | Returns: TRUE/FALSE |
| 370 | */ |
| 371 | |
| 372 | BOOL |
| 373 | smtp_buffered(void) |
| 374 | { |
| 375 | return smtp_inptr < smtp_inend; |
| 376 | } |
| 377 | |
| 378 | |
| 379 | |
| 380 | /************************************************* |
| 381 | * Write formatted string to SMTP channel * |
| 382 | *************************************************/ |
| 383 | |
| 384 | /* This is a separate function so that we don't have to repeat everything for |
| 385 | TLS support or debugging. It is global so that the daemon and the |
| 386 | authentication functions can use it. It does not return any error indication, |
| 387 | because major problems such as dropped connections won't show up till an output |
| 388 | flush for non-TLS connections. The smtp_fflush() function is available for |
| 389 | checking that: for convenience, TLS output errors are remembered here so that |
| 390 | they are also picked up later by smtp_fflush(). |
| 391 | |
| 392 | Arguments: |
| 393 | format format string |
| 394 | ... optional arguments |
| 395 | |
| 396 | Returns: nothing |
| 397 | */ |
| 398 | |
| 399 | void |
| 400 | smtp_printf(const char *format, ...) |
| 401 | { |
| 402 | va_list ap; |
| 403 | |
| 404 | va_start(ap, format); |
| 405 | smtp_vprintf(format, ap); |
| 406 | va_end(ap); |
| 407 | } |
| 408 | |
| 409 | /* This is split off so that verify.c:respond_printf() can, in effect, call |
| 410 | smtp_printf(), bearing in mind that in C a vararg function can't directly |
| 411 | call another vararg function, only a function which accepts a va_list. */ |
| 412 | |
| 413 | void |
| 414 | smtp_vprintf(const char *format, va_list ap) |
| 415 | { |
| 416 | BOOL yield; |
| 417 | |
| 418 | yield = string_vformat(big_buffer, big_buffer_size, format, ap); |
| 419 | |
| 420 | DEBUG(D_receive) |
| 421 | { |
| 422 | void *reset_point = store_get(0); |
| 423 | uschar *msg_copy, *cr, *end; |
| 424 | msg_copy = string_copy(big_buffer); |
| 425 | end = msg_copy + Ustrlen(msg_copy); |
| 426 | while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */ |
| 427 | memmove(cr, cr + 1, (end--) - cr); |
| 428 | debug_printf("SMTP>> %s", msg_copy); |
| 429 | store_reset(reset_point); |
| 430 | } |
| 431 | |
| 432 | if (!yield) |
| 433 | { |
| 434 | log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()"); |
| 435 | smtp_closedown(US"Unexpected error"); |
| 436 | exim_exit(EXIT_FAILURE); |
| 437 | } |
| 438 | |
| 439 | /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs |
| 440 | have had the same. Note: this code is also present in smtp_respond(). It would |
| 441 | be tidier to have it only in one place, but when it was added, it was easier to |
| 442 | do it that way, so as not to have to mess with the code for the RCPT command, |
| 443 | which sometimes uses smtp_printf() and sometimes smtp_respond(). */ |
| 444 | |
| 445 | if (rcpt_in_progress) |
| 446 | { |
| 447 | if (rcpt_smtp_response == NULL) |
| 448 | rcpt_smtp_response = string_copy(big_buffer); |
| 449 | else if (rcpt_smtp_response_same && |
| 450 | Ustrcmp(rcpt_smtp_response, big_buffer) != 0) |
| 451 | rcpt_smtp_response_same = FALSE; |
| 452 | rcpt_in_progress = FALSE; |
| 453 | } |
| 454 | |
| 455 | /* Now write the string */ |
| 456 | |
| 457 | #ifdef SUPPORT_TLS |
| 458 | if (tls_in.active >= 0) |
| 459 | { |
| 460 | if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0) |
| 461 | smtp_write_error = -1; |
| 462 | } |
| 463 | else |
| 464 | #endif |
| 465 | |
| 466 | if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1; |
| 467 | } |
| 468 | |
| 469 | |
| 470 | |
| 471 | /************************************************* |
| 472 | * Flush SMTP out and check for error * |
| 473 | *************************************************/ |
| 474 | |
| 475 | /* This function isn't currently used within Exim (it detects errors when it |
| 476 | tries to read the next SMTP input), but is available for use in local_scan(). |
| 477 | For non-TLS connections, it flushes the output and checks for errors. For |
| 478 | TLS-connections, it checks for a previously-detected TLS write error. |
| 479 | |
| 480 | Arguments: none |
| 481 | Returns: 0 for no error; -1 after an error |
| 482 | */ |
| 483 | |
| 484 | int |
| 485 | smtp_fflush(void) |
| 486 | { |
| 487 | if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1; |
| 488 | return smtp_write_error; |
| 489 | } |
| 490 | |
| 491 | |
| 492 | |
| 493 | /************************************************* |
| 494 | * SMTP command read timeout * |
| 495 | *************************************************/ |
| 496 | |
| 497 | /* Signal handler for timing out incoming SMTP commands. This attempts to |
| 498 | finish off tidily. |
| 499 | |
| 500 | Argument: signal number (SIGALRM) |
| 501 | Returns: nothing |
| 502 | */ |
| 503 | |
| 504 | static void |
| 505 | command_timeout_handler(int sig) |
| 506 | { |
| 507 | sig = sig; /* Keep picky compilers happy */ |
| 508 | log_write(L_lost_incoming_connection, |
| 509 | LOG_MAIN, "SMTP command timeout on%s connection from %s", |
| 510 | (tls_in.active >= 0)? " TLS" : "", |
| 511 | host_and_ident(FALSE)); |
| 512 | if (smtp_batched_input) |
| 513 | moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */ |
| 514 | smtp_notquit_exit(US"command-timeout", US"421", |
| 515 | US"%s: SMTP command timeout - closing connection", smtp_active_hostname); |
| 516 | exim_exit(EXIT_FAILURE); |
| 517 | } |
| 518 | |
| 519 | |
| 520 | |
| 521 | /************************************************* |
| 522 | * SIGTERM received * |
| 523 | *************************************************/ |
| 524 | |
| 525 | /* Signal handler for handling SIGTERM. Again, try to finish tidily. |
| 526 | |
| 527 | Argument: signal number (SIGTERM) |
| 528 | Returns: nothing |
| 529 | */ |
| 530 | |
| 531 | static void |
| 532 | command_sigterm_handler(int sig) |
| 533 | { |
| 534 | sig = sig; /* Keep picky compilers happy */ |
| 535 | log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info()); |
| 536 | if (smtp_batched_input) |
| 537 | moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */ |
| 538 | smtp_notquit_exit(US"signal-exit", US"421", |
| 539 | US"%s: Service not available - closing connection", smtp_active_hostname); |
| 540 | exim_exit(EXIT_FAILURE); |
| 541 | } |
| 542 | |
| 543 | |
| 544 | |
| 545 | |
| 546 | /************************************************* |
| 547 | * Read one command line * |
| 548 | *************************************************/ |
| 549 | |
| 550 | /* Strictly, SMTP commands coming over the net are supposed to end with CRLF. |
| 551 | There are sites that don't do this, and in any case internal SMTP probably |
| 552 | should check only for LF. Consequently, we check here for LF only. The line |
| 553 | ends up with [CR]LF removed from its end. If we get an overlong line, treat as |
| 554 | an unknown command. The command is read into the global smtp_cmd_buffer so that |
| 555 | it is available via $smtp_command. |
| 556 | |
| 557 | The character reading routine sets up a timeout for each block actually read |
| 558 | from the input (which may contain more than one command). We set up a special |
| 559 | signal handler that closes down the session on a timeout. Control does not |
| 560 | return when it runs. |
| 561 | |
| 562 | Arguments: |
| 563 | check_sync if TRUE, check synchronization rules if global option is TRUE |
| 564 | |
| 565 | Returns: a code identifying the command (enumerated above) |
| 566 | */ |
| 567 | |
| 568 | static int |
| 569 | smtp_read_command(BOOL check_sync) |
| 570 | { |
| 571 | int c; |
| 572 | int ptr = 0; |
| 573 | smtp_cmd_list *p; |
| 574 | BOOL hadnull = FALSE; |
| 575 | |
| 576 | os_non_restarting_signal(SIGALRM, command_timeout_handler); |
| 577 | |
| 578 | while ((c = (receive_getc)()) != '\n' && c != EOF) |
| 579 | { |
| 580 | if (ptr >= smtp_cmd_buffer_size) |
| 581 | { |
| 582 | os_non_restarting_signal(SIGALRM, sigalrm_handler); |
| 583 | return OTHER_CMD; |
| 584 | } |
| 585 | if (c == 0) |
| 586 | { |
| 587 | hadnull = TRUE; |
| 588 | c = '?'; |
| 589 | } |
| 590 | smtp_cmd_buffer[ptr++] = c; |
| 591 | } |
| 592 | |
| 593 | receive_linecount++; /* For BSMTP errors */ |
| 594 | os_non_restarting_signal(SIGALRM, sigalrm_handler); |
| 595 | |
| 596 | /* If hit end of file, return pseudo EOF command. Whether we have a |
| 597 | part-line already read doesn't matter, since this is an error state. */ |
| 598 | |
| 599 | if (c == EOF) return EOF_CMD; |
| 600 | |
| 601 | /* Remove any CR and white space at the end of the line, and terminate the |
| 602 | string. */ |
| 603 | |
| 604 | while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--; |
| 605 | smtp_cmd_buffer[ptr] = 0; |
| 606 | |
| 607 | DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer); |
| 608 | |
| 609 | /* NULLs are not allowed in SMTP commands */ |
| 610 | |
| 611 | if (hadnull) return BADCHAR_CMD; |
| 612 | |
| 613 | /* Scan command list and return identity, having set the data pointer |
| 614 | to the start of the actual data characters. Check for SMTP synchronization |
| 615 | if required. */ |
| 616 | |
| 617 | for (p = cmd_list; p < cmd_list_end; p++) |
| 618 | { |
| 619 | if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 && |
| 620 | (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */ |
| 621 | smtp_cmd_buffer[p->len] == 0 || |
| 622 | smtp_cmd_buffer[p->len] == ' ')) |
| 623 | { |
| 624 | if (smtp_inptr < smtp_inend && /* Outstanding input */ |
| 625 | p->cmd < sync_cmd_limit && /* Command should sync */ |
| 626 | check_sync && /* Local flag set */ |
| 627 | smtp_enforce_sync && /* Global flag set */ |
| 628 | sender_host_address != NULL && /* Not local input */ |
| 629 | !sender_host_notsocket) /* Really is a socket */ |
| 630 | return BADSYN_CMD; |
| 631 | |
| 632 | /* The variables $smtp_command and $smtp_command_argument point into the |
| 633 | unmodified input buffer. A copy of the latter is taken for actual |
| 634 | processing, so that it can be chopped up into separate parts if necessary, |
| 635 | for example, when processing a MAIL command options such as SIZE that can |
| 636 | follow the sender address. */ |
| 637 | |
| 638 | smtp_cmd_argument = smtp_cmd_buffer + p->len; |
| 639 | while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++; |
| 640 | Ustrcpy(smtp_data_buffer, smtp_cmd_argument); |
| 641 | smtp_cmd_data = smtp_data_buffer; |
| 642 | |
| 643 | /* Count non-mail commands from those hosts that are controlled in this |
| 644 | way. The default is all hosts. We don't waste effort checking the list |
| 645 | until we get a non-mail command, but then cache the result to save checking |
| 646 | again. If there's a DEFER while checking the host, assume it's in the list. |
| 647 | |
| 648 | Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the |
| 649 | start of each incoming message by fiddling with the value in the table. */ |
| 650 | |
| 651 | if (!p->is_mail_cmd) |
| 652 | { |
| 653 | if (count_nonmail == TRUE_UNSET) count_nonmail = |
| 654 | verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL; |
| 655 | if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail) |
| 656 | return TOO_MANY_NONMAIL_CMD; |
| 657 | } |
| 658 | |
| 659 | /* If there is data for a command that does not expect it, generate the |
| 660 | error here. */ |
| 661 | |
| 662 | return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD; |
| 663 | } |
| 664 | } |
| 665 | |
| 666 | /* Enforce synchronization for unknown commands */ |
| 667 | |
| 668 | if (smtp_inptr < smtp_inend && /* Outstanding input */ |
| 669 | check_sync && /* Local flag set */ |
| 670 | smtp_enforce_sync && /* Global flag set */ |
| 671 | sender_host_address != NULL && /* Not local input */ |
| 672 | !sender_host_notsocket) /* Really is a socket */ |
| 673 | return BADSYN_CMD; |
| 674 | |
| 675 | return OTHER_CMD; |
| 676 | } |
| 677 | |
| 678 | |
| 679 | |
| 680 | /************************************************* |
| 681 | * Recheck synchronization * |
| 682 | *************************************************/ |
| 683 | |
| 684 | /* Synchronization checks can never be perfect because a packet may be on its |
| 685 | way but not arrived when the check is done. Such checks can in any case only be |
| 686 | done when TLS is not in use. Normally, the checks happen when commands are |
| 687 | read: Exim ensures that there is no more input in the input buffer. In normal |
| 688 | cases, the response to the command will be fast, and there is no further check. |
| 689 | |
| 690 | However, for some commands an ACL is run, and that can include delays. In those |
| 691 | cases, it is useful to do another check on the input just before sending the |
| 692 | response. This also applies at the start of a connection. This function does |
| 693 | that check by means of the select() function, as long as the facility is not |
| 694 | disabled or inappropriate. A failure of select() is ignored. |
| 695 | |
| 696 | When there is unwanted input, we read it so that it appears in the log of the |
| 697 | error. |
| 698 | |
| 699 | Arguments: none |
| 700 | Returns: TRUE if all is well; FALSE if there is input pending |
| 701 | */ |
| 702 | |
| 703 | static BOOL |
| 704 | check_sync(void) |
| 705 | { |
| 706 | int fd, rc; |
| 707 | fd_set fds; |
| 708 | struct timeval tzero; |
| 709 | |
| 710 | if (!smtp_enforce_sync || sender_host_address == NULL || |
| 711 | sender_host_notsocket || tls_in.active >= 0) |
| 712 | return TRUE; |
| 713 | |
| 714 | fd = fileno(smtp_in); |
| 715 | FD_ZERO(&fds); |
| 716 | FD_SET(fd, &fds); |
| 717 | tzero.tv_sec = 0; |
| 718 | tzero.tv_usec = 0; |
| 719 | rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero); |
| 720 | |
| 721 | if (rc <= 0) return TRUE; /* Not ready to read */ |
| 722 | rc = smtp_getc(); |
| 723 | if (rc < 0) return TRUE; /* End of file or error */ |
| 724 | |
| 725 | smtp_ungetc(rc); |
| 726 | rc = smtp_inend - smtp_inptr; |
| 727 | if (rc > 150) rc = 150; |
| 728 | smtp_inptr[rc] = 0; |
| 729 | return FALSE; |
| 730 | } |
| 731 | |
| 732 | |
| 733 | |
| 734 | /************************************************* |
| 735 | * Forced closedown of call * |
| 736 | *************************************************/ |
| 737 | |
| 738 | /* This function is called from log.c when Exim is dying because of a serious |
| 739 | disaster, and also from some other places. If an incoming non-batched SMTP |
| 740 | channel is open, it swallows the rest of the incoming message if in the DATA |
| 741 | phase, sends the reply string, and gives an error to all subsequent commands |
| 742 | except QUIT. The existence of an SMTP call is detected by the non-NULLness of |
| 743 | smtp_in. |
| 744 | |
| 745 | Arguments: |
| 746 | message SMTP reply string to send, excluding the code |
| 747 | |
| 748 | Returns: nothing |
| 749 | */ |
| 750 | |
| 751 | void |
| 752 | smtp_closedown(uschar *message) |
| 753 | { |
| 754 | if (smtp_in == NULL || smtp_batched_input) return; |
| 755 | receive_swallow_smtp(); |
| 756 | smtp_printf("421 %s\r\n", message); |
| 757 | |
| 758 | for (;;) |
| 759 | { |
| 760 | switch(smtp_read_command(FALSE)) |
| 761 | { |
| 762 | case EOF_CMD: |
| 763 | return; |
| 764 | |
| 765 | case QUIT_CMD: |
| 766 | smtp_printf("221 %s closing connection\r\n", smtp_active_hostname); |
| 767 | mac_smtp_fflush(); |
| 768 | return; |
| 769 | |
| 770 | case RSET_CMD: |
| 771 | smtp_printf("250 Reset OK\r\n"); |
| 772 | break; |
| 773 | |
| 774 | default: |
| 775 | smtp_printf("421 %s\r\n", message); |
| 776 | break; |
| 777 | } |
| 778 | } |
| 779 | } |
| 780 | |
| 781 | |
| 782 | |
| 783 | |
| 784 | /************************************************* |
| 785 | * Set up connection info for logging * |
| 786 | *************************************************/ |
| 787 | |
| 788 | /* This function is called when logging information about an SMTP connection. |
| 789 | It sets up appropriate source information, depending on the type of connection. |
| 790 | If sender_fullhost is NULL, we are at a very early stage of the connection; |
| 791 | just use the IP address. |
| 792 | |
| 793 | Argument: none |
| 794 | Returns: a string describing the connection |
| 795 | */ |
| 796 | |
| 797 | uschar * |
| 798 | smtp_get_connection_info(void) |
| 799 | { |
| 800 | uschar *hostname = (sender_fullhost == NULL)? |
| 801 | sender_host_address : sender_fullhost; |
| 802 | |
| 803 | if (host_checking) |
| 804 | return string_sprintf("SMTP connection from %s", hostname); |
| 805 | |
| 806 | if (sender_host_unknown || sender_host_notsocket) |
| 807 | return string_sprintf("SMTP connection from %s", sender_ident); |
| 808 | |
| 809 | if (is_inetd) |
| 810 | return string_sprintf("SMTP connection from %s (via inetd)", hostname); |
| 811 | |
| 812 | if ((log_extra_selector & LX_incoming_interface) != 0 && |
| 813 | interface_address != NULL) |
| 814 | return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname, |
| 815 | interface_address, interface_port); |
| 816 | |
| 817 | return string_sprintf("SMTP connection from %s", hostname); |
| 818 | } |
| 819 | |
| 820 | |
| 821 | |
| 822 | /************************************************* |
| 823 | * Log lack of MAIL if so configured * |
| 824 | *************************************************/ |
| 825 | |
| 826 | /* This function is called when an SMTP session ends. If the log selector |
| 827 | smtp_no_mail is set, write a log line giving some details of what has happened |
| 828 | in the SMTP session. |
| 829 | |
| 830 | Arguments: none |
| 831 | Returns: nothing |
| 832 | */ |
| 833 | |
| 834 | void |
| 835 | smtp_log_no_mail(void) |
| 836 | { |
| 837 | int size, ptr, i; |
| 838 | uschar *s, *sep; |
| 839 | |
| 840 | if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0) |
| 841 | return; |
| 842 | |
| 843 | s = NULL; |
| 844 | size = ptr = 0; |
| 845 | |
| 846 | if (sender_host_authenticated != NULL) |
| 847 | { |
| 848 | s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated); |
| 849 | if (authenticated_id != NULL) |
| 850 | s = string_append(s, &size, &ptr, 2, US":", authenticated_id); |
| 851 | } |
| 852 | |
| 853 | #ifdef SUPPORT_TLS |
| 854 | if ((log_extra_selector & LX_tls_cipher) != 0 && tls_in.cipher != NULL) |
| 855 | s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher); |
| 856 | if ((log_extra_selector & LX_tls_certificate_verified) != 0 && |
| 857 | tls_in.cipher != NULL) |
| 858 | s = string_append(s, &size, &ptr, 2, US" CV=", |
| 859 | tls_in.certificate_verified? "yes":"no"); |
| 860 | if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_in.peerdn != NULL) |
| 861 | s = string_append(s, &size, &ptr, 3, US" DN=\"", |
| 862 | string_printing(tls_in.peerdn), US"\""); |
| 863 | if ((log_extra_selector & LX_tls_sni) != 0 && tls_in.sni != NULL) |
| 864 | s = string_append(s, &size, &ptr, 3, US" SNI=\"", |
| 865 | string_printing(tls_in.sni), US"\""); |
| 866 | #endif |
| 867 | |
| 868 | sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)? |
| 869 | US" C=..." : US" C="; |
| 870 | for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++) |
| 871 | { |
| 872 | if (smtp_connection_had[i] != SCH_NONE) |
| 873 | { |
| 874 | s = string_append(s, &size, &ptr, 2, sep, |
| 875 | smtp_names[smtp_connection_had[i]]); |
| 876 | sep = US","; |
| 877 | } |
| 878 | } |
| 879 | |
| 880 | for (i = 0; i < smtp_ch_index; i++) |
| 881 | { |
| 882 | s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]); |
| 883 | sep = US","; |
| 884 | } |
| 885 | |
| 886 | if (s != NULL) s[ptr] = 0; else s = US""; |
| 887 | log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s", |
| 888 | host_and_ident(FALSE), |
| 889 | readconf_printtime(time(NULL) - smtp_connection_start), s); |
| 890 | } |
| 891 | |
| 892 | |
| 893 | |
| 894 | /************************************************* |
| 895 | * Check HELO line and set sender_helo_name * |
| 896 | *************************************************/ |
| 897 | |
| 898 | /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be |
| 899 | the domain name of the sending host, or an ip literal in square brackets. The |
| 900 | arrgument is placed in sender_helo_name, which is in malloc store, because it |
| 901 | must persist over multiple incoming messages. If helo_accept_junk is set, this |
| 902 | host is permitted to send any old junk (needed for some broken hosts). |
| 903 | Otherwise, helo_allow_chars can be used for rogue characters in general |
| 904 | (typically people want to let in underscores). |
| 905 | |
| 906 | Argument: |
| 907 | s the data portion of the line (already past any white space) |
| 908 | |
| 909 | Returns: TRUE or FALSE |
| 910 | */ |
| 911 | |
| 912 | static BOOL |
| 913 | check_helo(uschar *s) |
| 914 | { |
| 915 | uschar *start = s; |
| 916 | uschar *end = s + Ustrlen(s); |
| 917 | BOOL yield = helo_accept_junk; |
| 918 | |
| 919 | /* Discard any previous helo name */ |
| 920 | |
| 921 | if (sender_helo_name != NULL) |
| 922 | { |
| 923 | store_free(sender_helo_name); |
| 924 | sender_helo_name = NULL; |
| 925 | } |
| 926 | |
| 927 | /* Skip tests if junk is permitted. */ |
| 928 | |
| 929 | if (!yield) |
| 930 | { |
| 931 | /* Allow the new standard form for IPv6 address literals, namely, |
| 932 | [IPv6:....], and because someone is bound to use it, allow an equivalent |
| 933 | IPv4 form. Allow plain addresses as well. */ |
| 934 | |
| 935 | if (*s == '[') |
| 936 | { |
| 937 | if (end[-1] == ']') |
| 938 | { |
| 939 | end[-1] = 0; |
| 940 | if (strncmpic(s, US"[IPv6:", 6) == 0) |
| 941 | yield = (string_is_ip_address(s+6, NULL) == 6); |
| 942 | else if (strncmpic(s, US"[IPv4:", 6) == 0) |
| 943 | yield = (string_is_ip_address(s+6, NULL) == 4); |
| 944 | else |
| 945 | yield = (string_is_ip_address(s+1, NULL) != 0); |
| 946 | end[-1] = ']'; |
| 947 | } |
| 948 | } |
| 949 | |
| 950 | /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars |
| 951 | that have been configured (usually underscore - sigh). */ |
| 952 | |
| 953 | else if (*s != 0) |
| 954 | { |
| 955 | yield = TRUE; |
| 956 | while (*s != 0) |
| 957 | { |
| 958 | if (!isalnum(*s) && *s != '.' && *s != '-' && |
| 959 | Ustrchr(helo_allow_chars, *s) == NULL) |
| 960 | { |
| 961 | yield = FALSE; |
| 962 | break; |
| 963 | } |
| 964 | s++; |
| 965 | } |
| 966 | } |
| 967 | } |
| 968 | |
| 969 | /* Save argument if OK */ |
| 970 | |
| 971 | if (yield) sender_helo_name = string_copy_malloc(start); |
| 972 | return yield; |
| 973 | } |
| 974 | |
| 975 | |
| 976 | |
| 977 | |
| 978 | |
| 979 | /************************************************* |
| 980 | * Extract SMTP command option * |
| 981 | *************************************************/ |
| 982 | |
| 983 | /* This function picks the next option setting off the end of smtp_cmd_data. It |
| 984 | is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP |
| 985 | things that can appear there. |
| 986 | |
| 987 | Arguments: |
| 988 | name point this at the name |
| 989 | value point this at the data string |
| 990 | |
| 991 | Returns: TRUE if found an option |
| 992 | */ |
| 993 | |
| 994 | static BOOL |
| 995 | extract_option(uschar **name, uschar **value) |
| 996 | { |
| 997 | uschar *n; |
| 998 | uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1; |
| 999 | while (isspace(*v)) v--; |
| 1000 | v[1] = 0; |
| 1001 | |
| 1002 | while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--; |
| 1003 | if (*v != '=') return FALSE; |
| 1004 | |
| 1005 | n = v; |
| 1006 | while(isalpha(n[-1])) n--; |
| 1007 | |
| 1008 | /* RFC says SP, but TAB seen in wild and other major MTAs accept it */ |
| 1009 | if (!isspace(n[-1])) return FALSE; |
| 1010 | |
| 1011 | n[-1] = 0; |
| 1012 | *name = n; |
| 1013 | *v++ = 0; |
| 1014 | *value = v; |
| 1015 | return TRUE; |
| 1016 | } |
| 1017 | |
| 1018 | |
| 1019 | |
| 1020 | |
| 1021 | |
| 1022 | /************************************************* |
| 1023 | * Reset for new message * |
| 1024 | *************************************************/ |
| 1025 | |
| 1026 | /* This function is called whenever the SMTP session is reset from |
| 1027 | within either of the setup functions. |
| 1028 | |
| 1029 | Argument: the stacking pool storage reset point |
| 1030 | Returns: nothing |
| 1031 | */ |
| 1032 | |
| 1033 | static void |
| 1034 | smtp_reset(void *reset_point) |
| 1035 | { |
| 1036 | store_reset(reset_point); |
| 1037 | recipients_list = NULL; |
| 1038 | rcpt_count = rcpt_defer_count = rcpt_fail_count = |
| 1039 | raw_recipients_count = recipients_count = recipients_list_max = 0; |
| 1040 | cancel_cutthrough_connection("smtp reset"); |
| 1041 | message_linecount = 0; |
| 1042 | message_size = -1; |
| 1043 | acl_added_headers = NULL; |
| 1044 | acl_removed_headers = NULL; |
| 1045 | queue_only_policy = FALSE; |
| 1046 | rcpt_smtp_response = NULL; |
| 1047 | rcpt_smtp_response_same = TRUE; |
| 1048 | rcpt_in_progress = FALSE; |
| 1049 | deliver_freeze = FALSE; /* Can be set by ACL */ |
| 1050 | freeze_tell = freeze_tell_config; /* Can be set by ACL */ |
| 1051 | fake_response = OK; /* Can be set by ACL */ |
| 1052 | #ifdef WITH_CONTENT_SCAN |
| 1053 | no_mbox_unspool = FALSE; /* Can be set by ACL */ |
| 1054 | #endif |
| 1055 | submission_mode = FALSE; /* Can be set by ACL */ |
| 1056 | suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */ |
| 1057 | active_local_from_check = local_from_check; /* Can be set by ACL */ |
| 1058 | active_local_sender_retain = local_sender_retain; /* Can be set by ACL */ |
| 1059 | sender_address = NULL; |
| 1060 | submission_name = NULL; /* Can be set by ACL */ |
| 1061 | raw_sender = NULL; /* After SMTP rewrite, before qualifying */ |
| 1062 | sender_address_unrewritten = NULL; /* Set only after verify rewrite */ |
| 1063 | sender_verified_list = NULL; /* No senders verified */ |
| 1064 | memset(sender_address_cache, 0, sizeof(sender_address_cache)); |
| 1065 | memset(sender_domain_cache, 0, sizeof(sender_domain_cache)); |
| 1066 | authenticated_sender = NULL; |
| 1067 | #ifdef EXPERIMENTAL_BRIGHTMAIL |
| 1068 | bmi_run = 0; |
| 1069 | bmi_verdicts = NULL; |
| 1070 | #endif |
| 1071 | #ifndef DISABLE_DKIM |
| 1072 | dkim_signers = NULL; |
| 1073 | dkim_disable_verify = FALSE; |
| 1074 | dkim_collect_input = FALSE; |
| 1075 | #endif |
| 1076 | #ifdef EXPERIMENTAL_SPF |
| 1077 | spf_header_comment = NULL; |
| 1078 | spf_received = NULL; |
| 1079 | spf_result = NULL; |
| 1080 | spf_smtp_comment = NULL; |
| 1081 | #endif |
| 1082 | body_linecount = body_zerocount = 0; |
| 1083 | |
| 1084 | sender_rate = sender_rate_limit = sender_rate_period = NULL; |
| 1085 | ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */ |
| 1086 | /* Note that ratelimiters_conn persists across resets. */ |
| 1087 | |
| 1088 | /* Reset message ACL variables */ |
| 1089 | |
| 1090 | acl_var_m = NULL; |
| 1091 | |
| 1092 | /* The message body variables use malloc store. They may be set if this is |
| 1093 | not the first message in an SMTP session and the previous message caused them |
| 1094 | to be referenced in an ACL. */ |
| 1095 | |
| 1096 | if (message_body != NULL) |
| 1097 | { |
| 1098 | store_free(message_body); |
| 1099 | message_body = NULL; |
| 1100 | } |
| 1101 | |
| 1102 | if (message_body_end != NULL) |
| 1103 | { |
| 1104 | store_free(message_body_end); |
| 1105 | message_body_end = NULL; |
| 1106 | } |
| 1107 | |
| 1108 | /* Warning log messages are also saved in malloc store. They are saved to avoid |
| 1109 | repetition in the same message, but it seems right to repeat them for different |
| 1110 | messages. */ |
| 1111 | |
| 1112 | while (acl_warn_logged != NULL) |
| 1113 | { |
| 1114 | string_item *this = acl_warn_logged; |
| 1115 | acl_warn_logged = acl_warn_logged->next; |
| 1116 | store_free(this); |
| 1117 | } |
| 1118 | } |
| 1119 | |
| 1120 | |
| 1121 | |
| 1122 | |
| 1123 | |
| 1124 | /************************************************* |
| 1125 | * Initialize for incoming batched SMTP message * |
| 1126 | *************************************************/ |
| 1127 | |
| 1128 | /* This function is called from smtp_setup_msg() in the case when |
| 1129 | smtp_batched_input is true. This happens when -bS is used to pass a whole batch |
| 1130 | of messages in one file with SMTP commands between them. All errors must be |
| 1131 | reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are |
| 1132 | relevant. After an error on a sender, or an invalid recipient, the remainder |
| 1133 | of the message is skipped. The value of received_protocol is already set. |
| 1134 | |
| 1135 | Argument: none |
| 1136 | Returns: > 0 message successfully started (reached DATA) |
| 1137 | = 0 QUIT read or end of file reached |
| 1138 | < 0 should not occur |
| 1139 | */ |
| 1140 | |
| 1141 | static int |
| 1142 | smtp_setup_batch_msg(void) |
| 1143 | { |
| 1144 | int done = 0; |
| 1145 | void *reset_point = store_get(0); |
| 1146 | |
| 1147 | /* Save the line count at the start of each transaction - single commands |
| 1148 | like HELO and RSET count as whole transactions. */ |
| 1149 | |
| 1150 | bsmtp_transaction_linecount = receive_linecount; |
| 1151 | |
| 1152 | if ((receive_feof)()) return 0; /* Treat EOF as QUIT */ |
| 1153 | |
| 1154 | smtp_reset(reset_point); /* Reset for start of message */ |
| 1155 | |
| 1156 | /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE |
| 1157 | value. The values are 2 larger than the required yield of the function. */ |
| 1158 | |
| 1159 | while (done <= 0) |
| 1160 | { |
| 1161 | uschar *errmess; |
| 1162 | uschar *recipient = NULL; |
| 1163 | int start, end, sender_domain, recipient_domain; |
| 1164 | |
| 1165 | switch(smtp_read_command(FALSE)) |
| 1166 | { |
| 1167 | /* The HELO/EHLO commands set sender_address_helo if they have |
| 1168 | valid data; otherwise they are ignored, except that they do |
| 1169 | a reset of the state. */ |
| 1170 | |
| 1171 | case HELO_CMD: |
| 1172 | case EHLO_CMD: |
| 1173 | |
| 1174 | check_helo(smtp_cmd_data); |
| 1175 | /* Fall through */ |
| 1176 | |
| 1177 | case RSET_CMD: |
| 1178 | smtp_reset(reset_point); |
| 1179 | bsmtp_transaction_linecount = receive_linecount; |
| 1180 | break; |
| 1181 | |
| 1182 | |
| 1183 | /* The MAIL FROM command requires an address as an operand. All we |
| 1184 | do here is to parse it for syntactic correctness. The form "<>" is |
| 1185 | a special case which converts into an empty string. The start/end |
| 1186 | pointers in the original are not used further for this address, as |
| 1187 | it is the canonical extracted address which is all that is kept. */ |
| 1188 | |
| 1189 | case MAIL_CMD: |
| 1190 | if (sender_address != NULL) |
| 1191 | /* The function moan_smtp_batch() does not return. */ |
| 1192 | moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given"); |
| 1193 | |
| 1194 | if (smtp_cmd_data[0] == 0) |
| 1195 | /* The function moan_smtp_batch() does not return. */ |
| 1196 | moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand"); |
| 1197 | |
| 1198 | /* Reset to start of message */ |
| 1199 | |
| 1200 | smtp_reset(reset_point); |
| 1201 | |
| 1202 | /* Apply SMTP rewrite */ |
| 1203 | |
| 1204 | raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)? |
| 1205 | rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE, |
| 1206 | US"", global_rewrite_rules) : smtp_cmd_data; |
| 1207 | |
| 1208 | /* Extract the address; the TRUE flag allows <> as valid */ |
| 1209 | |
| 1210 | raw_sender = |
| 1211 | parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain, |
| 1212 | TRUE); |
| 1213 | |
| 1214 | if (raw_sender == NULL) |
| 1215 | /* The function moan_smtp_batch() does not return. */ |
| 1216 | moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess); |
| 1217 | |
| 1218 | sender_address = string_copy(raw_sender); |
| 1219 | |
| 1220 | /* Qualify unqualified sender addresses if permitted to do so. */ |
| 1221 | |
| 1222 | if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@') |
| 1223 | { |
| 1224 | if (allow_unqualified_sender) |
| 1225 | { |
| 1226 | sender_address = rewrite_address_qualify(sender_address, FALSE); |
| 1227 | DEBUG(D_receive) debug_printf("unqualified address %s accepted " |
| 1228 | "and rewritten\n", raw_sender); |
| 1229 | } |
| 1230 | /* The function moan_smtp_batch() does not return. */ |
| 1231 | else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain " |
| 1232 | "a domain"); |
| 1233 | } |
| 1234 | break; |
| 1235 | |
| 1236 | |
| 1237 | /* The RCPT TO command requires an address as an operand. All we do |
| 1238 | here is to parse it for syntactic correctness. There may be any number |
| 1239 | of RCPT TO commands, specifying multiple senders. We build them all into |
| 1240 | a data structure that is in argc/argv format. The start/end values |
| 1241 | given by parse_extract_address are not used, as we keep only the |
| 1242 | extracted address. */ |
| 1243 | |
| 1244 | case RCPT_CMD: |
| 1245 | if (sender_address == NULL) |
| 1246 | /* The function moan_smtp_batch() does not return. */ |
| 1247 | moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given"); |
| 1248 | |
| 1249 | if (smtp_cmd_data[0] == 0) |
| 1250 | /* The function moan_smtp_batch() does not return. */ |
| 1251 | moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand"); |
| 1252 | |
| 1253 | /* Check maximum number allowed */ |
| 1254 | |
| 1255 | if (recipients_max > 0 && recipients_count + 1 > recipients_max) |
| 1256 | /* The function moan_smtp_batch() does not return. */ |
| 1257 | moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients", |
| 1258 | recipients_max_reject? "552": "452"); |
| 1259 | |
| 1260 | /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a |
| 1261 | recipient address */ |
| 1262 | |
| 1263 | recipient = ((rewrite_existflags & rewrite_smtp) != 0)? |
| 1264 | rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"", |
| 1265 | global_rewrite_rules) : smtp_cmd_data; |
| 1266 | |
| 1267 | /* rfc821_domains = TRUE; << no longer needed */ |
| 1268 | recipient = parse_extract_address(recipient, &errmess, &start, &end, |
| 1269 | &recipient_domain, FALSE); |
| 1270 | /* rfc821_domains = FALSE; << no longer needed */ |
| 1271 | |
| 1272 | if (recipient == NULL) |
| 1273 | /* The function moan_smtp_batch() does not return. */ |
| 1274 | moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess); |
| 1275 | |
| 1276 | /* If the recipient address is unqualified, qualify it if permitted. Then |
| 1277 | add it to the list of recipients. */ |
| 1278 | |
| 1279 | if (recipient_domain == 0) |
| 1280 | { |
| 1281 | if (allow_unqualified_recipient) |
| 1282 | { |
| 1283 | DEBUG(D_receive) debug_printf("unqualified address %s accepted\n", |
| 1284 | recipient); |
| 1285 | recipient = rewrite_address_qualify(recipient, TRUE); |
| 1286 | } |
| 1287 | /* The function moan_smtp_batch() does not return. */ |
| 1288 | else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain " |
| 1289 | "a domain"); |
| 1290 | } |
| 1291 | receive_add_recipient(recipient, -1); |
| 1292 | break; |
| 1293 | |
| 1294 | |
| 1295 | /* The DATA command is legal only if it follows successful MAIL FROM |
| 1296 | and RCPT TO commands. This function is complete when a valid DATA |
| 1297 | command is encountered. */ |
| 1298 | |
| 1299 | case DATA_CMD: |
| 1300 | if (sender_address == NULL || recipients_count <= 0) |
| 1301 | { |
| 1302 | /* The function moan_smtp_batch() does not return. */ |
| 1303 | if (sender_address == NULL) |
| 1304 | moan_smtp_batch(smtp_cmd_buffer, |
| 1305 | "503 MAIL FROM:<sender> command must precede DATA"); |
| 1306 | else |
| 1307 | moan_smtp_batch(smtp_cmd_buffer, |
| 1308 | "503 RCPT TO:<recipient> must precede DATA"); |
| 1309 | } |
| 1310 | else |
| 1311 | { |
| 1312 | done = 3; /* DATA successfully achieved */ |
| 1313 | message_ended = END_NOTENDED; /* Indicate in middle of message */ |
| 1314 | } |
| 1315 | break; |
| 1316 | |
| 1317 | |
| 1318 | /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */ |
| 1319 | |
| 1320 | case VRFY_CMD: |
| 1321 | case EXPN_CMD: |
| 1322 | case HELP_CMD: |
| 1323 | case NOOP_CMD: |
| 1324 | case ETRN_CMD: |
| 1325 | bsmtp_transaction_linecount = receive_linecount; |
| 1326 | break; |
| 1327 | |
| 1328 | |
| 1329 | case EOF_CMD: |
| 1330 | case QUIT_CMD: |
| 1331 | done = 2; |
| 1332 | break; |
| 1333 | |
| 1334 | |
| 1335 | case BADARG_CMD: |
| 1336 | /* The function moan_smtp_batch() does not return. */ |
| 1337 | moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data"); |
| 1338 | break; |
| 1339 | |
| 1340 | |
| 1341 | case BADCHAR_CMD: |
| 1342 | /* The function moan_smtp_batch() does not return. */ |
| 1343 | moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command"); |
| 1344 | break; |
| 1345 | |
| 1346 | |
| 1347 | default: |
| 1348 | /* The function moan_smtp_batch() does not return. */ |
| 1349 | moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized"); |
| 1350 | break; |
| 1351 | } |
| 1352 | } |
| 1353 | |
| 1354 | return done - 2; /* Convert yield values */ |
| 1355 | } |
| 1356 | |
| 1357 | |
| 1358 | |
| 1359 | |
| 1360 | /************************************************* |
| 1361 | * Start an SMTP session * |
| 1362 | *************************************************/ |
| 1363 | |
| 1364 | /* This function is called at the start of an SMTP session. Thereafter, |
| 1365 | smtp_setup_msg() is called to initiate each separate message. This |
| 1366 | function does host-specific testing, and outputs the banner line. |
| 1367 | |
| 1368 | Arguments: none |
| 1369 | Returns: FALSE if the session can not continue; something has |
| 1370 | gone wrong, or the connection to the host is blocked |
| 1371 | */ |
| 1372 | |
| 1373 | BOOL |
| 1374 | smtp_start_session(void) |
| 1375 | { |
| 1376 | int size = 256; |
| 1377 | int ptr, esclen; |
| 1378 | uschar *user_msg, *log_msg; |
| 1379 | uschar *code, *esc; |
| 1380 | uschar *p, *s, *ss; |
| 1381 | |
| 1382 | smtp_connection_start = time(NULL); |
| 1383 | for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++) |
| 1384 | smtp_connection_had[smtp_ch_index] = SCH_NONE; |
| 1385 | smtp_ch_index = 0; |
| 1386 | |
| 1387 | /* Default values for certain variables */ |
| 1388 | |
| 1389 | helo_seen = esmtp = helo_accept_junk = FALSE; |
| 1390 | smtp_mailcmd_count = 0; |
| 1391 | count_nonmail = TRUE_UNSET; |
| 1392 | synprot_error_count = unknown_command_count = nonmail_command_count = 0; |
| 1393 | smtp_delay_mail = smtp_rlm_base; |
| 1394 | auth_advertised = FALSE; |
| 1395 | pipelining_advertised = FALSE; |
| 1396 | pipelining_enable = TRUE; |
| 1397 | sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING; |
| 1398 | smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */ |
| 1399 | |
| 1400 | memset(sender_host_cache, 0, sizeof(sender_host_cache)); |
| 1401 | |
| 1402 | /* If receiving by -bs from a trusted user, or testing with -bh, we allow |
| 1403 | authentication settings from -oMaa to remain in force. */ |
| 1404 | |
| 1405 | if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL; |
| 1406 | authenticated_by = NULL; |
| 1407 | |
| 1408 | #ifdef SUPPORT_TLS |
| 1409 | tls_in.cipher = tls_in.peerdn = NULL; |
| 1410 | tls_advertised = FALSE; |
| 1411 | #endif |
| 1412 | |
| 1413 | /* Reset ACL connection variables */ |
| 1414 | |
| 1415 | acl_var_c = NULL; |
| 1416 | |
| 1417 | /* Allow for trailing 0 in the command and data buffers. */ |
| 1418 | |
| 1419 | smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2); |
| 1420 | if (smtp_cmd_buffer == NULL) |
| 1421 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, |
| 1422 | "malloc() failed for SMTP command buffer"); |
| 1423 | smtp_cmd_buffer[0] = 0; |
| 1424 | smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1; |
| 1425 | |
| 1426 | /* For batched input, the protocol setting can be overridden from the |
| 1427 | command line by a trusted caller. */ |
| 1428 | |
| 1429 | if (smtp_batched_input) |
| 1430 | { |
| 1431 | if (received_protocol == NULL) received_protocol = US"local-bsmtp"; |
| 1432 | } |
| 1433 | |
| 1434 | /* For non-batched SMTP input, the protocol setting is forced here. It will be |
| 1435 | reset later if any of EHLO/AUTH/STARTTLS are received. */ |
| 1436 | |
| 1437 | else |
| 1438 | received_protocol = |
| 1439 | protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0); |
| 1440 | |
| 1441 | /* Set up the buffer for inputting using direct read() calls, and arrange to |
| 1442 | call the local functions instead of the standard C ones. */ |
| 1443 | |
| 1444 | smtp_inbuffer = (uschar *)malloc(in_buffer_size); |
| 1445 | if (smtp_inbuffer == NULL) |
| 1446 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer"); |
| 1447 | receive_getc = smtp_getc; |
| 1448 | receive_ungetc = smtp_ungetc; |
| 1449 | receive_feof = smtp_feof; |
| 1450 | receive_ferror = smtp_ferror; |
| 1451 | receive_smtp_buffered = smtp_buffered; |
| 1452 | smtp_inptr = smtp_inend = smtp_inbuffer; |
| 1453 | smtp_had_eof = smtp_had_error = 0; |
| 1454 | |
| 1455 | /* Set up the message size limit; this may be host-specific */ |
| 1456 | |
| 1457 | thismessage_size_limit = expand_string_integer(message_size_limit, TRUE); |
| 1458 | if (expand_string_message != NULL) |
| 1459 | { |
| 1460 | if (thismessage_size_limit == -1) |
| 1461 | log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: " |
| 1462 | "%s", expand_string_message); |
| 1463 | else |
| 1464 | log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: " |
| 1465 | "%s", expand_string_message); |
| 1466 | smtp_closedown(US"Temporary local problem - please try later"); |
| 1467 | return FALSE; |
| 1468 | } |
| 1469 | |
| 1470 | /* When a message is input locally via the -bs or -bS options, sender_host_ |
| 1471 | unknown is set unless -oMa was used to force an IP address, in which case it |
| 1472 | is checked like a real remote connection. When -bs is used from inetd, this |
| 1473 | flag is not set, causing the sending host to be checked. The code that deals |
| 1474 | with IP source routing (if configured) is never required for -bs or -bS and |
| 1475 | the flag sender_host_notsocket is used to suppress it. |
| 1476 | |
| 1477 | If smtp_accept_max and smtp_accept_reserve are set, keep some connections in |
| 1478 | reserve for certain hosts and/or networks. */ |
| 1479 | |
| 1480 | if (!sender_host_unknown) |
| 1481 | { |
| 1482 | int rc; |
| 1483 | BOOL reserved_host = FALSE; |
| 1484 | |
| 1485 | /* Look up IP options (source routing info) on the socket if this is not an |
| 1486 | -oMa "host", and if any are found, log them and drop the connection. |
| 1487 | |
| 1488 | Linux (and others now, see below) is different to everyone else, so there |
| 1489 | has to be some conditional compilation here. Versions of Linux before 2.1.15 |
| 1490 | used a structure whose name was "options". Somebody finally realized that |
| 1491 | this name was silly, and it got changed to "ip_options". I use the |
| 1492 | newer name here, but there is a fudge in the script that sets up os.h |
| 1493 | to define a macro in older Linux systems. |
| 1494 | |
| 1495 | Sigh. Linux is a fast-moving target. Another generation of Linux uses |
| 1496 | glibc 2, which has chosen ip_opts for the structure name. This is now |
| 1497 | really a glibc thing rather than a Linux thing, so the condition name |
| 1498 | has been changed to reflect this. It is relevant also to GNU/Hurd. |
| 1499 | |
| 1500 | Mac OS 10.x (Darwin) is like the later glibc versions, but without the |
| 1501 | setting of the __GLIBC__ macro, so we can't detect it automatically. There's |
| 1502 | a special macro defined in the os.h file. |
| 1503 | |
| 1504 | Some DGUX versions on older hardware appear not to support IP options at |
| 1505 | all, so there is now a general macro which can be set to cut out this |
| 1506 | support altogether. |
| 1507 | |
| 1508 | How to do this properly in IPv6 is not yet known. */ |
| 1509 | |
| 1510 | #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS) |
| 1511 | |
| 1512 | #ifdef GLIBC_IP_OPTIONS |
| 1513 | #if (!defined __GLIBC__) || (__GLIBC__ < 2) |
| 1514 | #define OPTSTYLE 1 |
| 1515 | #else |
| 1516 | #define OPTSTYLE 2 |
| 1517 | #endif |
| 1518 | #elif defined DARWIN_IP_OPTIONS |
| 1519 | #define OPTSTYLE 2 |
| 1520 | #else |
| 1521 | #define OPTSTYLE 3 |
| 1522 | #endif |
| 1523 | |
| 1524 | if (!host_checking && !sender_host_notsocket) |
| 1525 | { |
| 1526 | #if OPTSTYLE == 1 |
| 1527 | EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN; |
| 1528 | struct ip_options *ipopt = store_get(optlen); |
| 1529 | #elif OPTSTYLE == 2 |
| 1530 | struct ip_opts ipoptblock; |
| 1531 | struct ip_opts *ipopt = &ipoptblock; |
| 1532 | EXIM_SOCKLEN_T optlen = sizeof(ipoptblock); |
| 1533 | #else |
| 1534 | struct ipoption ipoptblock; |
| 1535 | struct ipoption *ipopt = &ipoptblock; |
| 1536 | EXIM_SOCKLEN_T optlen = sizeof(ipoptblock); |
| 1537 | #endif |
| 1538 | |
| 1539 | /* Occasional genuine failures of getsockopt() have been seen - for |
| 1540 | example, "reset by peer". Therefore, just log and give up on this |
| 1541 | call, unless the error is ENOPROTOOPT. This error is given by systems |
| 1542 | that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time |
| 1543 | of writing. So for that error, carry on - we just can't do an IP options |
| 1544 | check. */ |
| 1545 | |
| 1546 | DEBUG(D_receive) debug_printf("checking for IP options\n"); |
| 1547 | |
| 1548 | if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt), |
| 1549 | &optlen) < 0) |
| 1550 | { |
| 1551 | if (errno != ENOPROTOOPT) |
| 1552 | { |
| 1553 | log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s", |
| 1554 | host_and_ident(FALSE), strerror(errno)); |
| 1555 | smtp_printf("451 SMTP service not available\r\n"); |
| 1556 | return FALSE; |
| 1557 | } |
| 1558 | } |
| 1559 | |
| 1560 | /* Deal with any IP options that are set. On the systems I have looked at, |
| 1561 | the value of MAX_IPOPTLEN has been 40, meaning that there should never be |
| 1562 | more logging data than will fit in big_buffer. Nevertheless, after somebody |
| 1563 | questioned this code, I've added in some paranoid checking. */ |
| 1564 | |
| 1565 | else if (optlen > 0) |
| 1566 | { |
| 1567 | uschar *p = big_buffer; |
| 1568 | uschar *pend = big_buffer + big_buffer_size; |
| 1569 | uschar *opt, *adptr; |
| 1570 | int optcount; |
| 1571 | struct in_addr addr; |
| 1572 | |
| 1573 | #if OPTSTYLE == 1 |
| 1574 | uschar *optstart = (uschar *)(ipopt->__data); |
| 1575 | #elif OPTSTYLE == 2 |
| 1576 | uschar *optstart = (uschar *)(ipopt->ip_opts); |
| 1577 | #else |
| 1578 | uschar *optstart = (uschar *)(ipopt->ipopt_list); |
| 1579 | #endif |
| 1580 | |
| 1581 | DEBUG(D_receive) debug_printf("IP options exist\n"); |
| 1582 | |
| 1583 | Ustrcpy(p, "IP options on incoming call:"); |
| 1584 | p += Ustrlen(p); |
| 1585 | |
| 1586 | for (opt = optstart; opt != NULL && |
| 1587 | opt < (uschar *)(ipopt) + optlen;) |
| 1588 | { |
| 1589 | switch (*opt) |
| 1590 | { |
| 1591 | case IPOPT_EOL: |
| 1592 | opt = NULL; |
| 1593 | break; |
| 1594 | |
| 1595 | case IPOPT_NOP: |
| 1596 | opt++; |
| 1597 | break; |
| 1598 | |
| 1599 | case IPOPT_SSRR: |
| 1600 | case IPOPT_LSRR: |
| 1601 | if (!string_format(p, pend-p, " %s [@%s", |
| 1602 | (*opt == IPOPT_SSRR)? "SSRR" : "LSRR", |
| 1603 | #if OPTSTYLE == 1 |
| 1604 | inet_ntoa(*((struct in_addr *)(&(ipopt->faddr)))))) |
| 1605 | #elif OPTSTYLE == 2 |
| 1606 | inet_ntoa(ipopt->ip_dst))) |
| 1607 | #else |
| 1608 | inet_ntoa(ipopt->ipopt_dst))) |
| 1609 | #endif |
| 1610 | { |
| 1611 | opt = NULL; |
| 1612 | break; |
| 1613 | } |
| 1614 | |
| 1615 | p += Ustrlen(p); |
| 1616 | optcount = (opt[1] - 3) / sizeof(struct in_addr); |
| 1617 | adptr = opt + 3; |
| 1618 | while (optcount-- > 0) |
| 1619 | { |
| 1620 | memcpy(&addr, adptr, sizeof(addr)); |
| 1621 | if (!string_format(p, pend - p - 1, "%s%s", |
| 1622 | (optcount == 0)? ":" : "@", inet_ntoa(addr))) |
| 1623 | { |
| 1624 | opt = NULL; |
| 1625 | break; |
| 1626 | } |
| 1627 | p += Ustrlen(p); |
| 1628 | adptr += sizeof(struct in_addr); |
| 1629 | } |
| 1630 | *p++ = ']'; |
| 1631 | opt += opt[1]; |
| 1632 | break; |
| 1633 | |
| 1634 | default: |
| 1635 | { |
| 1636 | int i; |
| 1637 | if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; } |
| 1638 | Ustrcat(p, "[ "); |
| 1639 | p += 2; |
| 1640 | for (i = 0; i < opt[1]; i++) |
| 1641 | { |
| 1642 | sprintf(CS p, "%2.2x ", opt[i]); |
| 1643 | p += 3; |
| 1644 | } |
| 1645 | *p++ = ']'; |
| 1646 | } |
| 1647 | opt += opt[1]; |
| 1648 | break; |
| 1649 | } |
| 1650 | } |
| 1651 | |
| 1652 | *p = 0; |
| 1653 | log_write(0, LOG_MAIN, "%s", big_buffer); |
| 1654 | |
| 1655 | /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */ |
| 1656 | |
| 1657 | log_write(0, LOG_MAIN|LOG_REJECT, |
| 1658 | "connection from %s refused (IP options)", host_and_ident(FALSE)); |
| 1659 | |
| 1660 | smtp_printf("554 SMTP service not available\r\n"); |
| 1661 | return FALSE; |
| 1662 | } |
| 1663 | |
| 1664 | /* Length of options = 0 => there are no options */ |
| 1665 | |
| 1666 | else DEBUG(D_receive) debug_printf("no IP options found\n"); |
| 1667 | } |
| 1668 | #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */ |
| 1669 | |
| 1670 | /* Set keep-alive in socket options. The option is on by default. This |
| 1671 | setting is an attempt to get rid of some hanging connections that stick in |
| 1672 | read() when the remote end (usually a dialup) goes away. */ |
| 1673 | |
| 1674 | if (smtp_accept_keepalive && !sender_host_notsocket) |
| 1675 | ip_keepalive(fileno(smtp_out), sender_host_address, FALSE); |
| 1676 | |
| 1677 | /* If the current host matches host_lookup, set the name by doing a |
| 1678 | reverse lookup. On failure, sender_host_name will be NULL and |
| 1679 | host_lookup_failed will be TRUE. This may or may not be serious - optional |
| 1680 | checks later. */ |
| 1681 | |
| 1682 | if (verify_check_host(&host_lookup) == OK) |
| 1683 | { |
| 1684 | (void)host_name_lookup(); |
| 1685 | host_build_sender_fullhost(); |
| 1686 | } |
| 1687 | |
| 1688 | /* Delay this until we have the full name, if it is looked up. */ |
| 1689 | |
| 1690 | set_process_info("handling incoming connection from %s", |
| 1691 | host_and_ident(FALSE)); |
| 1692 | |
| 1693 | /* Start up TLS if tls_on_connect is set. This is for supporting the legacy |
| 1694 | smtps port for use with older style SSL MTAs. */ |
| 1695 | |
| 1696 | #ifdef SUPPORT_TLS |
| 1697 | if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK) |
| 1698 | return FALSE; |
| 1699 | #endif |
| 1700 | |
| 1701 | /* Test for explicit connection rejection */ |
| 1702 | |
| 1703 | if (verify_check_host(&host_reject_connection) == OK) |
| 1704 | { |
| 1705 | log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection " |
| 1706 | "from %s (host_reject_connection)", host_and_ident(FALSE)); |
| 1707 | smtp_printf("554 SMTP service not available\r\n"); |
| 1708 | return FALSE; |
| 1709 | } |
| 1710 | |
| 1711 | /* Test with TCP Wrappers if so configured. There is a problem in that |
| 1712 | hosts_ctl() returns 0 (deny) under a number of system failure circumstances, |
| 1713 | such as disks dying. In these cases, it is desirable to reject with a 4xx |
| 1714 | error instead of a 5xx error. There isn't a "right" way to detect such |
| 1715 | problems. The following kludge is used: errno is zeroed before calling |
| 1716 | hosts_ctl(). If the result is "reject", a 5xx error is given only if the |
| 1717 | value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does |
| 1718 | not exist). */ |
| 1719 | |
| 1720 | #ifdef USE_TCP_WRAPPERS |
| 1721 | errno = 0; |
| 1722 | tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name); |
| 1723 | if (tcp_wrappers_name == NULL) |
| 1724 | { |
| 1725 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" " |
| 1726 | "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name), |
| 1727 | expand_string_message); |
| 1728 | } |
| 1729 | if (!hosts_ctl(tcp_wrappers_name, |
| 1730 | (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name, |
| 1731 | (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address, |
| 1732 | (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident)) |
| 1733 | { |
| 1734 | if (errno == 0 || errno == ENOENT) |
| 1735 | { |
| 1736 | HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n"); |
| 1737 | log_write(L_connection_reject, |
| 1738 | LOG_MAIN|LOG_REJECT, "refused connection from %s " |
| 1739 | "(tcp wrappers)", host_and_ident(FALSE)); |
| 1740 | smtp_printf("554 SMTP service not available\r\n"); |
| 1741 | } |
| 1742 | else |
| 1743 | { |
| 1744 | int save_errno = errno; |
| 1745 | HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected " |
| 1746 | "errno value %d\n", save_errno); |
| 1747 | log_write(L_connection_reject, |
| 1748 | LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s " |
| 1749 | "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno); |
| 1750 | smtp_printf("451 Temporary local problem - please try later\r\n"); |
| 1751 | } |
| 1752 | return FALSE; |
| 1753 | } |
| 1754 | #endif |
| 1755 | |
| 1756 | /* Check for reserved slots. The value of smtp_accept_count has already been |
| 1757 | incremented to include this process. */ |
| 1758 | |
| 1759 | if (smtp_accept_max > 0 && |
| 1760 | smtp_accept_count > smtp_accept_max - smtp_accept_reserve) |
| 1761 | { |
| 1762 | if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK) |
| 1763 | { |
| 1764 | log_write(L_connection_reject, |
| 1765 | LOG_MAIN, "temporarily refused connection from %s: not in " |
| 1766 | "reserve list: connected=%d max=%d reserve=%d%s", |
| 1767 | host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max, |
| 1768 | smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : ""); |
| 1769 | smtp_printf("421 %s: Too many concurrent SMTP connections; " |
| 1770 | "please try again later\r\n", smtp_active_hostname); |
| 1771 | return FALSE; |
| 1772 | } |
| 1773 | reserved_host = TRUE; |
| 1774 | } |
| 1775 | |
| 1776 | /* If a load level above which only messages from reserved hosts are |
| 1777 | accepted is set, check the load. For incoming calls via the daemon, the |
| 1778 | check is done in the superior process if there are no reserved hosts, to |
| 1779 | save a fork. In all cases, the load average will already be available |
| 1780 | in a global variable at this point. */ |
| 1781 | |
| 1782 | if (smtp_load_reserve >= 0 && |
| 1783 | load_average > smtp_load_reserve && |
| 1784 | !reserved_host && |
| 1785 | verify_check_host(&smtp_reserve_hosts) != OK) |
| 1786 | { |
| 1787 | log_write(L_connection_reject, |
| 1788 | LOG_MAIN, "temporarily refused connection from %s: not in " |
| 1789 | "reserve list and load average = %.2f", host_and_ident(FALSE), |
| 1790 | (double)load_average/1000.0); |
| 1791 | smtp_printf("421 %s: Too much load; please try again later\r\n", |
| 1792 | smtp_active_hostname); |
| 1793 | return FALSE; |
| 1794 | } |
| 1795 | |
| 1796 | /* Determine whether unqualified senders or recipients are permitted |
| 1797 | for this host. Unfortunately, we have to do this every time, in order to |
| 1798 | set the flags so that they can be inspected when considering qualifying |
| 1799 | addresses in the headers. For a site that permits no qualification, this |
| 1800 | won't take long, however. */ |
| 1801 | |
| 1802 | allow_unqualified_sender = |
| 1803 | verify_check_host(&sender_unqualified_hosts) == OK; |
| 1804 | |
| 1805 | allow_unqualified_recipient = |
| 1806 | verify_check_host(&recipient_unqualified_hosts) == OK; |
| 1807 | |
| 1808 | /* Determine whether HELO/EHLO is required for this host. The requirement |
| 1809 | can be hard or soft. */ |
| 1810 | |
| 1811 | helo_required = verify_check_host(&helo_verify_hosts) == OK; |
| 1812 | if (!helo_required) |
| 1813 | helo_verify = verify_check_host(&helo_try_verify_hosts) == OK; |
| 1814 | |
| 1815 | /* Determine whether this hosts is permitted to send syntactic junk |
| 1816 | after a HELO or EHLO command. */ |
| 1817 | |
| 1818 | helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK; |
| 1819 | } |
| 1820 | |
| 1821 | /* For batch SMTP input we are now done. */ |
| 1822 | |
| 1823 | if (smtp_batched_input) return TRUE; |
| 1824 | |
| 1825 | /* Run the ACL if it exists */ |
| 1826 | |
| 1827 | user_msg = NULL; |
| 1828 | if (acl_smtp_connect != NULL) |
| 1829 | { |
| 1830 | int rc; |
| 1831 | rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg, |
| 1832 | &log_msg); |
| 1833 | if (rc != OK) |
| 1834 | { |
| 1835 | (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg); |
| 1836 | return FALSE; |
| 1837 | } |
| 1838 | } |
| 1839 | |
| 1840 | /* Output the initial message for a two-way SMTP connection. It may contain |
| 1841 | newlines, which then cause a multi-line response to be given. */ |
| 1842 | |
| 1843 | code = US"220"; /* Default status code */ |
| 1844 | esc = US""; /* Default extended status code */ |
| 1845 | esclen = 0; /* Length of esc */ |
| 1846 | |
| 1847 | if (user_msg == NULL) |
| 1848 | { |
| 1849 | s = expand_string(smtp_banner); |
| 1850 | if (s == NULL) |
| 1851 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) " |
| 1852 | "failed: %s", smtp_banner, expand_string_message); |
| 1853 | } |
| 1854 | else |
| 1855 | { |
| 1856 | int codelen = 3; |
| 1857 | s = user_msg; |
| 1858 | smtp_message_code(&code, &codelen, &s, NULL); |
| 1859 | if (codelen > 4) |
| 1860 | { |
| 1861 | esc = code + 4; |
| 1862 | esclen = codelen - 4; |
| 1863 | } |
| 1864 | } |
| 1865 | |
| 1866 | /* Remove any terminating newlines; might as well remove trailing space too */ |
| 1867 | |
| 1868 | p = s + Ustrlen(s); |
| 1869 | while (p > s && isspace(p[-1])) p--; |
| 1870 | *p = 0; |
| 1871 | |
| 1872 | /* It seems that CC:Mail is braindead, and assumes that the greeting message |
| 1873 | is all contained in a single IP packet. The original code wrote out the |
| 1874 | greeting using several calls to fprint/fputc, and on busy servers this could |
| 1875 | cause it to be split over more than one packet - which caused CC:Mail to fall |
| 1876 | over when it got the second part of the greeting after sending its first |
| 1877 | command. Sigh. To try to avoid this, build the complete greeting message |
| 1878 | first, and output it in one fell swoop. This gives a better chance of it |
| 1879 | ending up as a single packet. */ |
| 1880 | |
| 1881 | ss = store_get(size); |
| 1882 | ptr = 0; |
| 1883 | |
| 1884 | p = s; |
| 1885 | do /* At least once, in case we have an empty string */ |
| 1886 | { |
| 1887 | int len; |
| 1888 | uschar *linebreak = Ustrchr(p, '\n'); |
| 1889 | ss = string_cat(ss, &size, &ptr, code, 3); |
| 1890 | if (linebreak == NULL) |
| 1891 | { |
| 1892 | len = Ustrlen(p); |
| 1893 | ss = string_cat(ss, &size, &ptr, US" ", 1); |
| 1894 | } |
| 1895 | else |
| 1896 | { |
| 1897 | len = linebreak - p; |
| 1898 | ss = string_cat(ss, &size, &ptr, US"-", 1); |
| 1899 | } |
| 1900 | ss = string_cat(ss, &size, &ptr, esc, esclen); |
| 1901 | ss = string_cat(ss, &size, &ptr, p, len); |
| 1902 | ss = string_cat(ss, &size, &ptr, US"\r\n", 2); |
| 1903 | p += len; |
| 1904 | if (linebreak != NULL) p++; |
| 1905 | } |
| 1906 | while (*p != 0); |
| 1907 | |
| 1908 | ss[ptr] = 0; /* string_cat leaves room for this */ |
| 1909 | |
| 1910 | /* Before we write the banner, check that there is no input pending, unless |
| 1911 | this synchronisation check is disabled. */ |
| 1912 | |
| 1913 | if (!check_sync()) |
| 1914 | { |
| 1915 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol " |
| 1916 | "synchronization error (input sent without waiting for greeting): " |
| 1917 | "rejected connection from %s input=\"%s\"", host_and_ident(TRUE), |
| 1918 | string_printing(smtp_inptr)); |
| 1919 | smtp_printf("554 SMTP synchronization error\r\n"); |
| 1920 | return FALSE; |
| 1921 | } |
| 1922 | |
| 1923 | /* Now output the banner */ |
| 1924 | |
| 1925 | smtp_printf("%s", ss); |
| 1926 | return TRUE; |
| 1927 | } |
| 1928 | |
| 1929 | |
| 1930 | |
| 1931 | |
| 1932 | |
| 1933 | /************************************************* |
| 1934 | * Handle SMTP syntax and protocol errors * |
| 1935 | *************************************************/ |
| 1936 | |
| 1937 | /* Write to the log for SMTP syntax errors in incoming commands, if configured |
| 1938 | to do so. Then transmit the error response. The return value depends on the |
| 1939 | number of syntax and protocol errors in this SMTP session. |
| 1940 | |
| 1941 | Arguments: |
| 1942 | type error type, given as a log flag bit |
| 1943 | code response code; <= 0 means don't send a response |
| 1944 | data data to reflect in the response (can be NULL) |
| 1945 | errmess the error message |
| 1946 | |
| 1947 | Returns: -1 limit of syntax/protocol errors NOT exceeded |
| 1948 | +1 limit of syntax/protocol errors IS exceeded |
| 1949 | |
| 1950 | These values fit in with the values of the "done" variable in the main |
| 1951 | processing loop in smtp_setup_msg(). */ |
| 1952 | |
| 1953 | static int |
| 1954 | synprot_error(int type, int code, uschar *data, uschar *errmess) |
| 1955 | { |
| 1956 | int yield = -1; |
| 1957 | |
| 1958 | log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s", |
| 1959 | (type == L_smtp_syntax_error)? "syntax" : "protocol", |
| 1960 | string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess); |
| 1961 | |
| 1962 | if (++synprot_error_count > smtp_max_synprot_errors) |
| 1963 | { |
| 1964 | yield = 1; |
| 1965 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " |
| 1966 | "syntax or protocol errors (last command was \"%s\")", |
| 1967 | host_and_ident(FALSE), smtp_cmd_buffer); |
| 1968 | } |
| 1969 | |
| 1970 | if (code > 0) |
| 1971 | { |
| 1972 | smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ', |
| 1973 | (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess); |
| 1974 | if (yield == 1) |
| 1975 | smtp_printf("%d Too many syntax or protocol errors\r\n", code); |
| 1976 | } |
| 1977 | |
| 1978 | return yield; |
| 1979 | } |
| 1980 | |
| 1981 | |
| 1982 | |
| 1983 | |
| 1984 | /************************************************* |
| 1985 | * Log incomplete transactions * |
| 1986 | *************************************************/ |
| 1987 | |
| 1988 | /* This function is called after a transaction has been aborted by RSET, QUIT, |
| 1989 | connection drops or other errors. It logs the envelope information received |
| 1990 | so far in order to preserve address verification attempts. |
| 1991 | |
| 1992 | Argument: string to indicate what aborted the transaction |
| 1993 | Returns: nothing |
| 1994 | */ |
| 1995 | |
| 1996 | static void |
| 1997 | incomplete_transaction_log(uschar *what) |
| 1998 | { |
| 1999 | if (sender_address == NULL || /* No transaction in progress */ |
| 2000 | (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */ |
| 2001 | ) return; |
| 2002 | |
| 2003 | /* Build list of recipients for logging */ |
| 2004 | |
| 2005 | if (recipients_count > 0) |
| 2006 | { |
| 2007 | int i; |
| 2008 | raw_recipients = store_get(recipients_count * sizeof(uschar *)); |
| 2009 | for (i = 0; i < recipients_count; i++) |
| 2010 | raw_recipients[i] = recipients_list[i].address; |
| 2011 | raw_recipients_count = recipients_count; |
| 2012 | } |
| 2013 | |
| 2014 | log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS, |
| 2015 | "%s incomplete transaction (%s)", host_and_ident(TRUE), what); |
| 2016 | } |
| 2017 | |
| 2018 | |
| 2019 | |
| 2020 | |
| 2021 | /************************************************* |
| 2022 | * Send SMTP response, possibly multiline * |
| 2023 | *************************************************/ |
| 2024 | |
| 2025 | /* There are, it seems, broken clients out there that cannot handle multiline |
| 2026 | responses. If no_multiline_responses is TRUE (it can be set from an ACL), we |
| 2027 | output nothing for non-final calls, and only the first line for anything else. |
| 2028 | |
| 2029 | Arguments: |
| 2030 | code SMTP code, may involve extended status codes |
| 2031 | codelen length of smtp code; if > 4 there's an ESC |
| 2032 | final FALSE if the last line isn't the final line |
| 2033 | msg message text, possibly containing newlines |
| 2034 | |
| 2035 | Returns: nothing |
| 2036 | */ |
| 2037 | |
| 2038 | void |
| 2039 | smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg) |
| 2040 | { |
| 2041 | int esclen = 0; |
| 2042 | uschar *esc = US""; |
| 2043 | |
| 2044 | if (!final && no_multiline_responses) return; |
| 2045 | |
| 2046 | if (codelen > 4) |
| 2047 | { |
| 2048 | esc = code + 4; |
| 2049 | esclen = codelen - 4; |
| 2050 | } |
| 2051 | |
| 2052 | /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs |
| 2053 | have had the same. Note: this code is also present in smtp_printf(). It would |
| 2054 | be tidier to have it only in one place, but when it was added, it was easier to |
| 2055 | do it that way, so as not to have to mess with the code for the RCPT command, |
| 2056 | which sometimes uses smtp_printf() and sometimes smtp_respond(). */ |
| 2057 | |
| 2058 | if (rcpt_in_progress) |
| 2059 | { |
| 2060 | if (rcpt_smtp_response == NULL) |
| 2061 | rcpt_smtp_response = string_copy(msg); |
| 2062 | else if (rcpt_smtp_response_same && |
| 2063 | Ustrcmp(rcpt_smtp_response, msg) != 0) |
| 2064 | rcpt_smtp_response_same = FALSE; |
| 2065 | rcpt_in_progress = FALSE; |
| 2066 | } |
| 2067 | |
| 2068 | /* Not output the message, splitting it up into multiple lines if necessary. */ |
| 2069 | |
| 2070 | for (;;) |
| 2071 | { |
| 2072 | uschar *nl = Ustrchr(msg, '\n'); |
| 2073 | if (nl == NULL) |
| 2074 | { |
| 2075 | smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg); |
| 2076 | return; |
| 2077 | } |
| 2078 | else if (nl[1] == 0 || no_multiline_responses) |
| 2079 | { |
| 2080 | smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc, |
| 2081 | (int)(nl - msg), msg); |
| 2082 | return; |
| 2083 | } |
| 2084 | else |
| 2085 | { |
| 2086 | smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg); |
| 2087 | msg = nl + 1; |
| 2088 | while (isspace(*msg)) msg++; |
| 2089 | } |
| 2090 | } |
| 2091 | } |
| 2092 | |
| 2093 | |
| 2094 | |
| 2095 | |
| 2096 | /************************************************* |
| 2097 | * Parse user SMTP message * |
| 2098 | *************************************************/ |
| 2099 | |
| 2100 | /* This function allows for user messages overriding the response code details |
| 2101 | by providing a suitable response code string at the start of the message |
| 2102 | user_msg. Check the message for starting with a response code and optionally an |
| 2103 | extended status code. If found, check that the first digit is valid, and if so, |
| 2104 | change the code pointer and length to use the replacement. An invalid code |
| 2105 | causes a panic log; in this case, if the log messages is the same as the user |
| 2106 | message, we must also adjust the value of the log message to show the code that |
| 2107 | is actually going to be used (the original one). |
| 2108 | |
| 2109 | This function is global because it is called from receive.c as well as within |
| 2110 | this module. |
| 2111 | |
| 2112 | Note that the code length returned includes the terminating whitespace |
| 2113 | character, which is always included in the regex match. |
| 2114 | |
| 2115 | Arguments: |
| 2116 | code SMTP code, may involve extended status codes |
| 2117 | codelen length of smtp code; if > 4 there's an ESC |
| 2118 | msg message text |
| 2119 | log_msg optional log message, to be adjusted with the new SMTP code |
| 2120 | |
| 2121 | Returns: nothing |
| 2122 | */ |
| 2123 | |
| 2124 | void |
| 2125 | smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg) |
| 2126 | { |
| 2127 | int n; |
| 2128 | int ovector[3]; |
| 2129 | |
| 2130 | if (msg == NULL || *msg == NULL) return; |
| 2131 | |
| 2132 | n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0, |
| 2133 | PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int)); |
| 2134 | if (n < 0) return; |
| 2135 | |
| 2136 | if ((*msg)[0] != (*code)[0]) |
| 2137 | { |
| 2138 | log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with " |
| 2139 | "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg); |
| 2140 | if (log_msg != NULL && *log_msg == *msg) |
| 2141 | *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]); |
| 2142 | } |
| 2143 | else |
| 2144 | { |
| 2145 | *code = *msg; |
| 2146 | *codelen = ovector[1]; /* Includes final space */ |
| 2147 | } |
| 2148 | *msg += ovector[1]; /* Chop the code off the message */ |
| 2149 | return; |
| 2150 | } |
| 2151 | |
| 2152 | |
| 2153 | |
| 2154 | |
| 2155 | /************************************************* |
| 2156 | * Handle an ACL failure * |
| 2157 | *************************************************/ |
| 2158 | |
| 2159 | /* This function is called when acl_check() fails. As well as calls from within |
| 2160 | this module, it is called from receive.c for an ACL after DATA. It sorts out |
| 2161 | logging the incident, and sets up the error response. A message containing |
| 2162 | newlines is turned into a multiline SMTP response, but for logging, only the |
| 2163 | first line is used. |
| 2164 | |
| 2165 | There's a table of default permanent failure response codes to use in |
| 2166 | globals.c, along with the table of names. VFRY is special. Despite RFC1123 it |
| 2167 | defaults disabled in Exim. However, discussion in connection with RFC 821bis |
| 2168 | (aka RFC 2821) has concluded that the response should be 252 in the disabled |
| 2169 | state, because there are broken clients that try VRFY before RCPT. A 5xx |
| 2170 | response should be given only when the address is positively known to be |
| 2171 | undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH, |
| 2172 | 503. |
| 2173 | |
| 2174 | From Exim 4.63, it is possible to override the response code details by |
| 2175 | providing a suitable response code string at the start of the message provided |
| 2176 | in user_msg. The code's first digit is checked for validity. |
| 2177 | |
| 2178 | Arguments: |
| 2179 | where where the ACL was called from |
| 2180 | rc the failure code |
| 2181 | user_msg a message that can be included in an SMTP response |
| 2182 | log_msg a message for logging |
| 2183 | |
| 2184 | Returns: 0 in most cases |
| 2185 | 2 if the failure code was FAIL_DROP, in which case the |
| 2186 | SMTP connection should be dropped (this value fits with the |
| 2187 | "done" variable in smtp_setup_msg() below) |
| 2188 | */ |
| 2189 | |
| 2190 | int |
| 2191 | smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg) |
| 2192 | { |
| 2193 | BOOL drop = rc == FAIL_DROP; |
| 2194 | int codelen = 3; |
| 2195 | uschar *smtp_code; |
| 2196 | uschar *lognl; |
| 2197 | uschar *sender_info = US""; |
| 2198 | uschar *what = |
| 2199 | #ifdef WITH_CONTENT_SCAN |
| 2200 | (where == ACL_WHERE_MIME)? US"during MIME ACL checks" : |
| 2201 | #endif |
| 2202 | (where == ACL_WHERE_PREDATA)? US"DATA" : |
| 2203 | (where == ACL_WHERE_DATA)? US"after DATA" : |
| 2204 | (smtp_cmd_data == NULL)? |
| 2205 | string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) : |
| 2206 | string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data); |
| 2207 | |
| 2208 | if (drop) rc = FAIL; |
| 2209 | |
| 2210 | /* Set the default SMTP code, and allow a user message to change it. */ |
| 2211 | |
| 2212 | smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where]; |
| 2213 | smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg); |
| 2214 | |
| 2215 | /* We used to have sender_address here; however, there was a bug that was not |
| 2216 | updating sender_address after a rewrite during a verify. When this bug was |
| 2217 | fixed, sender_address at this point became the rewritten address. I'm not sure |
| 2218 | this is what should be logged, so I've changed to logging the unrewritten |
| 2219 | address to retain backward compatibility. */ |
| 2220 | |
| 2221 | #ifndef WITH_CONTENT_SCAN |
| 2222 | if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA) |
| 2223 | #else |
| 2224 | if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME) |
| 2225 | #endif |
| 2226 | { |
| 2227 | sender_info = string_sprintf("F=<%s>%s%s%s%s ", |
| 2228 | sender_address_unrewritten ? sender_address_unrewritten : sender_address, |
| 2229 | sender_host_authenticated ? US" A=" : US"", |
| 2230 | sender_host_authenticated ? sender_host_authenticated : US"", |
| 2231 | sender_host_authenticated && authenticated_id ? US":" : US"", |
| 2232 | sender_host_authenticated && authenticated_id ? authenticated_id : US"" |
| 2233 | ); |
| 2234 | } |
| 2235 | |
| 2236 | /* If there's been a sender verification failure with a specific message, and |
| 2237 | we have not sent a response about it yet, do so now, as a preliminary line for |
| 2238 | failures, but not defers. However, always log it for defer, and log it for fail |
| 2239 | unless the sender_verify_fail log selector has been turned off. */ |
| 2240 | |
| 2241 | if (sender_verified_failed != NULL && |
| 2242 | !testflag(sender_verified_failed, af_sverify_told)) |
| 2243 | { |
| 2244 | BOOL save_rcpt_in_progress = rcpt_in_progress; |
| 2245 | rcpt_in_progress = FALSE; /* So as not to treat these as the error */ |
| 2246 | |
| 2247 | setflag(sender_verified_failed, af_sverify_told); |
| 2248 | |
| 2249 | if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0) |
| 2250 | log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s", |
| 2251 | host_and_ident(TRUE), |
| 2252 | ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail", |
| 2253 | sender_verified_failed->address, |
| 2254 | (sender_verified_failed->message == NULL)? US"" : |
| 2255 | string_sprintf(": %s", sender_verified_failed->message)); |
| 2256 | |
| 2257 | if (rc == FAIL && sender_verified_failed->user_message != NULL) |
| 2258 | smtp_respond(smtp_code, codelen, FALSE, string_sprintf( |
| 2259 | testflag(sender_verified_failed, af_verify_pmfail)? |
| 2260 | "Postmaster verification failed while checking <%s>\n%s\n" |
| 2261 | "Several RFCs state that you are required to have a postmaster\n" |
| 2262 | "mailbox for each mail domain. This host does not accept mail\n" |
| 2263 | "from domains whose servers reject the postmaster address." |
| 2264 | : |
| 2265 | testflag(sender_verified_failed, af_verify_nsfail)? |
| 2266 | "Callback setup failed while verifying <%s>\n%s\n" |
| 2267 | "The initial connection, or a HELO or MAIL FROM:<> command was\n" |
| 2268 | "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n" |
| 2269 | "RFC requirements, and stops you from receiving standard bounce\n" |
| 2270 | "messages. This host does not accept mail from domains whose servers\n" |
| 2271 | "refuse bounces." |
| 2272 | : |
| 2273 | "Verification failed for <%s>\n%s", |
| 2274 | sender_verified_failed->address, |
| 2275 | sender_verified_failed->user_message)); |
| 2276 | |
| 2277 | rcpt_in_progress = save_rcpt_in_progress; |
| 2278 | } |
| 2279 | |
| 2280 | /* Sort out text for logging */ |
| 2281 | |
| 2282 | log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg); |
| 2283 | lognl = Ustrchr(log_msg, '\n'); |
| 2284 | if (lognl != NULL) *lognl = 0; |
| 2285 | |
| 2286 | /* Send permanent failure response to the command, but the code used isn't |
| 2287 | always a 5xx one - see comments at the start of this function. If the original |
| 2288 | rc was FAIL_DROP we drop the connection and yield 2. */ |
| 2289 | |
| 2290 | if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)? |
| 2291 | US"Administrative prohibition" : user_msg); |
| 2292 | |
| 2293 | /* Send temporary failure response to the command. Don't give any details, |
| 2294 | unless acl_temp_details is set. This is TRUE for a callout defer, a "defer" |
| 2295 | verb, and for a header verify when smtp_return_error_details is set. |
| 2296 | |
| 2297 | This conditional logic is all somewhat of a mess because of the odd |
| 2298 | interactions between temp_details and return_error_details. One day it should |
| 2299 | be re-implemented in a tidier fashion. */ |
| 2300 | |
| 2301 | else |
| 2302 | { |
| 2303 | if (acl_temp_details && user_msg != NULL) |
| 2304 | { |
| 2305 | if (smtp_return_error_details && |
| 2306 | sender_verified_failed != NULL && |
| 2307 | sender_verified_failed->message != NULL) |
| 2308 | { |
| 2309 | smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message); |
| 2310 | } |
| 2311 | smtp_respond(smtp_code, codelen, TRUE, user_msg); |
| 2312 | } |
| 2313 | else |
| 2314 | smtp_respond(smtp_code, codelen, TRUE, |
| 2315 | US"Temporary local problem - please try later"); |
| 2316 | } |
| 2317 | |
| 2318 | /* Log the incident to the logs that are specified by log_reject_target |
| 2319 | (default main, reject). This can be empty to suppress logging of rejections. If |
| 2320 | the connection is not forcibly to be dropped, return 0. Otherwise, log why it |
| 2321 | is closing if required and return 2. */ |
| 2322 | |
| 2323 | if (log_reject_target != 0) |
| 2324 | log_write(0, log_reject_target, "%s %s%srejected %s%s", |
| 2325 | host_and_ident(TRUE), |
| 2326 | sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg); |
| 2327 | |
| 2328 | if (!drop) return 0; |
| 2329 | |
| 2330 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL", |
| 2331 | smtp_get_connection_info()); |
| 2332 | |
| 2333 | /* Run the not-quit ACL, but without any custom messages. This should not be a |
| 2334 | problem, because we get here only if some other ACL has issued "drop", and |
| 2335 | in that case, *its* custom messages will have been used above. */ |
| 2336 | |
| 2337 | smtp_notquit_exit(US"acl-drop", NULL, NULL); |
| 2338 | return 2; |
| 2339 | } |
| 2340 | |
| 2341 | |
| 2342 | |
| 2343 | |
| 2344 | /************************************************* |
| 2345 | * Handle SMTP exit when QUIT is not given * |
| 2346 | *************************************************/ |
| 2347 | |
| 2348 | /* This function provides a logging/statistics hook for when an SMTP connection |
| 2349 | is dropped on the floor or the other end goes away. It's a global function |
| 2350 | because it's called from receive.c as well as this module. As well as running |
| 2351 | the NOTQUIT ACL, if there is one, this function also outputs a final SMTP |
| 2352 | response, either with a custom message from the ACL, or using a default. There |
| 2353 | is one case, however, when no message is output - after "drop". In that case, |
| 2354 | the ACL that obeyed "drop" has already supplied the custom message, and NULL is |
| 2355 | passed to this function. |
| 2356 | |
| 2357 | In case things go wrong while processing this function, causing an error that |
| 2358 | may re-enter this funtion, there is a recursion check. |
| 2359 | |
| 2360 | Arguments: |
| 2361 | reason What $smtp_notquit_reason will be set to in the ACL; |
| 2362 | if NULL, the ACL is not run |
| 2363 | code The error code to return as part of the response |
| 2364 | defaultrespond The default message if there's no user_msg |
| 2365 | |
| 2366 | Returns: Nothing |
| 2367 | */ |
| 2368 | |
| 2369 | void |
| 2370 | smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...) |
| 2371 | { |
| 2372 | int rc; |
| 2373 | uschar *user_msg = NULL; |
| 2374 | uschar *log_msg = NULL; |
| 2375 | |
| 2376 | /* Check for recursive acll */ |
| 2377 | |
| 2378 | if (smtp_exit_function_called) |
| 2379 | { |
| 2380 | log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)", |
| 2381 | reason); |
| 2382 | return; |
| 2383 | } |
| 2384 | smtp_exit_function_called = TRUE; |
| 2385 | |
| 2386 | /* Call the not-QUIT ACL, if there is one, unless no reason is given. */ |
| 2387 | |
| 2388 | if (acl_smtp_notquit != NULL && reason != NULL) |
| 2389 | { |
| 2390 | smtp_notquit_reason = reason; |
| 2391 | rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg, |
| 2392 | &log_msg); |
| 2393 | if (rc == ERROR) |
| 2394 | log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s", |
| 2395 | log_msg); |
| 2396 | } |
| 2397 | |
| 2398 | /* Write an SMTP response if we are expected to give one. As the default |
| 2399 | responses are all internal, they should always fit in the buffer, but code a |
| 2400 | warning, just in case. Note that string_vformat() still leaves a complete |
| 2401 | string, even if it is incomplete. */ |
| 2402 | |
| 2403 | if (code != NULL && defaultrespond != NULL) |
| 2404 | { |
| 2405 | if (user_msg == NULL) |
| 2406 | { |
| 2407 | uschar buffer[128]; |
| 2408 | va_list ap; |
| 2409 | va_start(ap, defaultrespond); |
| 2410 | if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap)) |
| 2411 | log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()"); |
| 2412 | smtp_printf("%s %s\r\n", code, buffer); |
| 2413 | va_end(ap); |
| 2414 | } |
| 2415 | else |
| 2416 | smtp_respond(code, 3, TRUE, user_msg); |
| 2417 | mac_smtp_fflush(); |
| 2418 | } |
| 2419 | } |
| 2420 | |
| 2421 | |
| 2422 | |
| 2423 | |
| 2424 | /************************************************* |
| 2425 | * Verify HELO argument * |
| 2426 | *************************************************/ |
| 2427 | |
| 2428 | /* This function is called if helo_verify_hosts or helo_try_verify_hosts is |
| 2429 | matched. It is also called from ACL processing if verify = helo is used and |
| 2430 | verification was not previously tried (i.e. helo_try_verify_hosts was not |
| 2431 | matched). The result of its processing is to set helo_verified and |
| 2432 | helo_verify_failed. These variables should both be FALSE for this function to |
| 2433 | be called. |
| 2434 | |
| 2435 | Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow |
| 2436 | for IPv6 ::ffff: literals. |
| 2437 | |
| 2438 | Argument: none |
| 2439 | Returns: TRUE if testing was completed; |
| 2440 | FALSE on a temporary failure |
| 2441 | */ |
| 2442 | |
| 2443 | BOOL |
| 2444 | smtp_verify_helo(void) |
| 2445 | { |
| 2446 | BOOL yield = TRUE; |
| 2447 | |
| 2448 | HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n", |
| 2449 | sender_helo_name); |
| 2450 | |
| 2451 | if (sender_helo_name == NULL) |
| 2452 | { |
| 2453 | HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n"); |
| 2454 | } |
| 2455 | |
| 2456 | /* Deal with the case of -bs without an IP address */ |
| 2457 | |
| 2458 | else if (sender_host_address == NULL) |
| 2459 | { |
| 2460 | HDEBUG(D_receive) debug_printf("no client IP address: assume success\n"); |
| 2461 | helo_verified = TRUE; |
| 2462 | } |
| 2463 | |
| 2464 | /* Deal with the more common case when there is a sending IP address */ |
| 2465 | |
| 2466 | else if (sender_helo_name[0] == '[') |
| 2467 | { |
| 2468 | helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address, |
| 2469 | Ustrlen(sender_host_address)) == 0; |
| 2470 | |
| 2471 | #if HAVE_IPV6 |
| 2472 | if (!helo_verified) |
| 2473 | { |
| 2474 | if (strncmpic(sender_host_address, US"::ffff:", 7) == 0) |
| 2475 | helo_verified = Ustrncmp(sender_helo_name + 1, |
| 2476 | sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0; |
| 2477 | } |
| 2478 | #endif |
| 2479 | |
| 2480 | HDEBUG(D_receive) |
| 2481 | { if (helo_verified) debug_printf("matched host address\n"); } |
| 2482 | } |
| 2483 | |
| 2484 | /* Do a reverse lookup if one hasn't already given a positive or negative |
| 2485 | response. If that fails, or the name doesn't match, try checking with a forward |
| 2486 | lookup. */ |
| 2487 | |
| 2488 | else |
| 2489 | { |
| 2490 | if (sender_host_name == NULL && !host_lookup_failed) |
| 2491 | yield = host_name_lookup() != DEFER; |
| 2492 | |
| 2493 | /* If a host name is known, check it and all its aliases. */ |
| 2494 | |
| 2495 | if (sender_host_name != NULL) |
| 2496 | { |
| 2497 | helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0; |
| 2498 | |
| 2499 | if (helo_verified) |
| 2500 | { |
| 2501 | HDEBUG(D_receive) debug_printf("matched host name\n"); |
| 2502 | } |
| 2503 | else |
| 2504 | { |
| 2505 | uschar **aliases = sender_host_aliases; |
| 2506 | while (*aliases != NULL) |
| 2507 | { |
| 2508 | helo_verified = strcmpic(*aliases++, sender_helo_name) == 0; |
| 2509 | if (helo_verified) break; |
| 2510 | } |
| 2511 | HDEBUG(D_receive) |
| 2512 | { |
| 2513 | if (helo_verified) |
| 2514 | debug_printf("matched alias %s\n", *(--aliases)); |
| 2515 | } |
| 2516 | } |
| 2517 | } |
| 2518 | |
| 2519 | /* Final attempt: try a forward lookup of the helo name */ |
| 2520 | |
| 2521 | if (!helo_verified) |
| 2522 | { |
| 2523 | int rc; |
| 2524 | host_item h; |
| 2525 | h.name = sender_helo_name; |
| 2526 | h.address = NULL; |
| 2527 | h.mx = MX_NONE; |
| 2528 | h.next = NULL; |
| 2529 | HDEBUG(D_receive) debug_printf("getting IP address for %s\n", |
| 2530 | sender_helo_name); |
| 2531 | rc = host_find_byname(&h, NULL, 0, NULL, TRUE); |
| 2532 | if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL) |
| 2533 | { |
| 2534 | host_item *hh = &h; |
| 2535 | while (hh != NULL) |
| 2536 | { |
| 2537 | if (Ustrcmp(hh->address, sender_host_address) == 0) |
| 2538 | { |
| 2539 | helo_verified = TRUE; |
| 2540 | HDEBUG(D_receive) |
| 2541 | debug_printf("IP address for %s matches calling address\n", |
| 2542 | sender_helo_name); |
| 2543 | break; |
| 2544 | } |
| 2545 | hh = hh->next; |
| 2546 | } |
| 2547 | } |
| 2548 | } |
| 2549 | } |
| 2550 | |
| 2551 | if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */ |
| 2552 | return yield; |
| 2553 | } |
| 2554 | |
| 2555 | |
| 2556 | |
| 2557 | |
| 2558 | /************************************************* |
| 2559 | * Send user response message * |
| 2560 | *************************************************/ |
| 2561 | |
| 2562 | /* This function is passed a default response code and a user message. It calls |
| 2563 | smtp_message_code() to check and possibly modify the response code, and then |
| 2564 | calls smtp_respond() to transmit the response. I put this into a function |
| 2565 | just to avoid a lot of repetition. |
| 2566 | |
| 2567 | Arguments: |
| 2568 | code the response code |
| 2569 | user_msg the user message |
| 2570 | |
| 2571 | Returns: nothing |
| 2572 | */ |
| 2573 | |
| 2574 | static void |
| 2575 | smtp_user_msg(uschar *code, uschar *user_msg) |
| 2576 | { |
| 2577 | int len = 3; |
| 2578 | smtp_message_code(&code, &len, &user_msg, NULL); |
| 2579 | smtp_respond(code, len, TRUE, user_msg); |
| 2580 | } |
| 2581 | |
| 2582 | |
| 2583 | |
| 2584 | |
| 2585 | /************************************************* |
| 2586 | * Initialize for SMTP incoming message * |
| 2587 | *************************************************/ |
| 2588 | |
| 2589 | /* This function conducts the initial dialogue at the start of an incoming SMTP |
| 2590 | message, and builds a list of recipients. However, if the incoming message |
| 2591 | is part of a batch (-bS option) a separate function is called since it would |
| 2592 | be messy having tests splattered about all over this function. This function |
| 2593 | therefore handles the case where interaction is occurring. The input and output |
| 2594 | files are set up in smtp_in and smtp_out. |
| 2595 | |
| 2596 | The global recipients_list is set to point to a vector of recipient_item |
| 2597 | blocks, whose number is given by recipients_count. This is extended by the |
| 2598 | receive_add_recipient() function. The global variable sender_address is set to |
| 2599 | the sender's address. The yield is +1 if a message has been successfully |
| 2600 | started, 0 if a QUIT command was encountered or the connection was refused from |
| 2601 | the particular host, or -1 if the connection was lost. |
| 2602 | |
| 2603 | Argument: none |
| 2604 | |
| 2605 | Returns: > 0 message successfully started (reached DATA) |
| 2606 | = 0 QUIT read or end of file reached or call refused |
| 2607 | < 0 lost connection |
| 2608 | */ |
| 2609 | |
| 2610 | int |
| 2611 | smtp_setup_msg(void) |
| 2612 | { |
| 2613 | int done = 0; |
| 2614 | BOOL toomany = FALSE; |
| 2615 | BOOL discarded = FALSE; |
| 2616 | BOOL last_was_rej_mail = FALSE; |
| 2617 | BOOL last_was_rcpt = FALSE; |
| 2618 | void *reset_point = store_get(0); |
| 2619 | |
| 2620 | DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n"); |
| 2621 | |
| 2622 | /* Reset for start of new message. We allow one RSET not to be counted as a |
| 2623 | nonmail command, for those MTAs that insist on sending it between every |
| 2624 | message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of |
| 2625 | TLS between messages (an Exim client may do this if it has messages queued up |
| 2626 | for the host). Note: we do NOT reset AUTH at this point. */ |
| 2627 | |
| 2628 | smtp_reset(reset_point); |
| 2629 | message_ended = END_NOTSTARTED; |
| 2630 | |
| 2631 | cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE; |
| 2632 | cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE; |
| 2633 | cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE; |
| 2634 | #ifdef SUPPORT_TLS |
| 2635 | cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE; |
| 2636 | #endif |
| 2637 | |
| 2638 | /* Set the local signal handler for SIGTERM - it tries to end off tidily */ |
| 2639 | |
| 2640 | os_non_restarting_signal(SIGTERM, command_sigterm_handler); |
| 2641 | |
| 2642 | /* Batched SMTP is handled in a different function. */ |
| 2643 | |
| 2644 | if (smtp_batched_input) return smtp_setup_batch_msg(); |
| 2645 | |
| 2646 | /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE |
| 2647 | value. The values are 2 larger than the required yield of the function. */ |
| 2648 | |
| 2649 | while (done <= 0) |
| 2650 | { |
| 2651 | uschar **argv; |
| 2652 | uschar *etrn_command; |
| 2653 | uschar *etrn_serialize_key; |
| 2654 | uschar *errmess; |
| 2655 | uschar *log_msg, *smtp_code; |
| 2656 | uschar *user_msg = NULL; |
| 2657 | uschar *recipient = NULL; |
| 2658 | uschar *hello = NULL; |
| 2659 | uschar *set_id = NULL; |
| 2660 | uschar *s, *ss; |
| 2661 | BOOL was_rej_mail = FALSE; |
| 2662 | BOOL was_rcpt = FALSE; |
| 2663 | void (*oldsignal)(int); |
| 2664 | pid_t pid; |
| 2665 | int start, end, sender_domain, recipient_domain; |
| 2666 | int ptr, size, rc; |
| 2667 | int c, i; |
| 2668 | auth_instance *au; |
| 2669 | |
| 2670 | switch(smtp_read_command(TRUE)) |
| 2671 | { |
| 2672 | /* The AUTH command is not permitted to occur inside a transaction, and may |
| 2673 | occur successfully only once per connection. Actually, that isn't quite |
| 2674 | true. When TLS is started, all previous information about a connection must |
| 2675 | be discarded, so a new AUTH is permitted at that time. |
| 2676 | |
| 2677 | AUTH may only be used when it has been advertised. However, it seems that |
| 2678 | there are clients that send AUTH when it hasn't been advertised, some of |
| 2679 | them even doing this after HELO. And there are MTAs that accept this. Sigh. |
| 2680 | So there's a get-out that allows this to happen. |
| 2681 | |
| 2682 | AUTH is initially labelled as a "nonmail command" so that one occurrence |
| 2683 | doesn't get counted. We change the label here so that multiple failing |
| 2684 | AUTHS will eventually hit the nonmail threshold. */ |
| 2685 | |
| 2686 | case AUTH_CMD: |
| 2687 | HAD(SCH_AUTH); |
| 2688 | authentication_failed = TRUE; |
| 2689 | cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE; |
| 2690 | |
| 2691 | if (!auth_advertised && !allow_auth_unadvertised) |
| 2692 | { |
| 2693 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 2694 | US"AUTH command used when not advertised"); |
| 2695 | break; |
| 2696 | } |
| 2697 | if (sender_host_authenticated != NULL) |
| 2698 | { |
| 2699 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 2700 | US"already authenticated"); |
| 2701 | break; |
| 2702 | } |
| 2703 | if (sender_address != NULL) |
| 2704 | { |
| 2705 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 2706 | US"not permitted in mail transaction"); |
| 2707 | break; |
| 2708 | } |
| 2709 | |
| 2710 | /* Check the ACL */ |
| 2711 | |
| 2712 | if (acl_smtp_auth != NULL) |
| 2713 | { |
| 2714 | rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg); |
| 2715 | if (rc != OK) |
| 2716 | { |
| 2717 | done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg); |
| 2718 | break; |
| 2719 | } |
| 2720 | } |
| 2721 | |
| 2722 | /* Find the name of the requested authentication mechanism. */ |
| 2723 | |
| 2724 | s = smtp_cmd_data; |
| 2725 | while ((c = *smtp_cmd_data) != 0 && !isspace(c)) |
| 2726 | { |
| 2727 | if (!isalnum(c) && c != '-' && c != '_') |
| 2728 | { |
| 2729 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 2730 | US"invalid character in authentication mechanism name"); |
| 2731 | goto COMMAND_LOOP; |
| 2732 | } |
| 2733 | smtp_cmd_data++; |
| 2734 | } |
| 2735 | |
| 2736 | /* If not at the end of the line, we must be at white space. Terminate the |
| 2737 | name and move the pointer on to any data that may be present. */ |
| 2738 | |
| 2739 | if (*smtp_cmd_data != 0) |
| 2740 | { |
| 2741 | *smtp_cmd_data++ = 0; |
| 2742 | while (isspace(*smtp_cmd_data)) smtp_cmd_data++; |
| 2743 | } |
| 2744 | |
| 2745 | /* Search for an authentication mechanism which is configured for use |
| 2746 | as a server and which has been advertised (unless, sigh, allow_auth_ |
| 2747 | unadvertised is set). */ |
| 2748 | |
| 2749 | for (au = auths; au != NULL; au = au->next) |
| 2750 | { |
| 2751 | if (strcmpic(s, au->public_name) == 0 && au->server && |
| 2752 | (au->advertised || allow_auth_unadvertised)) break; |
| 2753 | } |
| 2754 | |
| 2755 | if (au == NULL) |
| 2756 | { |
| 2757 | done = synprot_error(L_smtp_protocol_error, 504, NULL, |
| 2758 | string_sprintf("%s authentication mechanism not supported", s)); |
| 2759 | break; |
| 2760 | } |
| 2761 | |
| 2762 | /* Run the checking code, passing the remainder of the command line as |
| 2763 | data. Initials the $auth<n> variables as empty. Initialize $0 empty and set |
| 2764 | it as the only set numerical variable. The authenticator may set $auth<n> |
| 2765 | and also set other numeric variables. The $auth<n> variables are preferred |
| 2766 | nowadays; the numerical variables remain for backwards compatibility. |
| 2767 | |
| 2768 | Afterwards, have a go at expanding the set_id string, even if |
| 2769 | authentication failed - for bad passwords it can be useful to log the |
| 2770 | userid. On success, require set_id to expand and exist, and put it in |
| 2771 | authenticated_id. Save this in permanent store, as the working store gets |
| 2772 | reset at HELO, RSET, etc. */ |
| 2773 | |
| 2774 | for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; |
| 2775 | expand_nmax = 0; |
| 2776 | expand_nlength[0] = 0; /* $0 contains nothing */ |
| 2777 | |
| 2778 | c = (au->info->servercode)(au, smtp_cmd_data); |
| 2779 | if (au->set_id != NULL) set_id = expand_string(au->set_id); |
| 2780 | expand_nmax = -1; /* Reset numeric variables */ |
| 2781 | for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */ |
| 2782 | |
| 2783 | /* The value of authenticated_id is stored in the spool file and printed in |
| 2784 | log lines. It must not contain binary zeros or newline characters. In |
| 2785 | normal use, it never will, but when playing around or testing, this error |
| 2786 | can (did) happen. To guard against this, ensure that the id contains only |
| 2787 | printing characters. */ |
| 2788 | |
| 2789 | if (set_id != NULL) set_id = string_printing(set_id); |
| 2790 | |
| 2791 | /* For the non-OK cases, set up additional logging data if set_id |
| 2792 | is not empty. */ |
| 2793 | |
| 2794 | if (c != OK) |
| 2795 | { |
| 2796 | if (set_id != NULL && *set_id != 0) |
| 2797 | set_id = string_sprintf(" (set_id=%s)", set_id); |
| 2798 | else set_id = US""; |
| 2799 | } |
| 2800 | |
| 2801 | /* Switch on the result */ |
| 2802 | |
| 2803 | switch(c) |
| 2804 | { |
| 2805 | case OK: |
| 2806 | if (au->set_id == NULL || set_id != NULL) /* Complete success */ |
| 2807 | { |
| 2808 | if (set_id != NULL) authenticated_id = string_copy_malloc(set_id); |
| 2809 | sender_host_authenticated = au->name; |
| 2810 | authentication_failed = FALSE; |
| 2811 | received_protocol = |
| 2812 | protocols[pextend + pauthed + ((tls_in.active >= 0)? pcrpted:0)] + |
| 2813 | ((sender_host_address != NULL)? pnlocal : 0); |
| 2814 | s = ss = US"235 Authentication succeeded"; |
| 2815 | authenticated_by = au; |
| 2816 | break; |
| 2817 | } |
| 2818 | |
| 2819 | /* Authentication succeeded, but we failed to expand the set_id string. |
| 2820 | Treat this as a temporary error. */ |
| 2821 | |
| 2822 | auth_defer_msg = expand_string_message; |
| 2823 | /* Fall through */ |
| 2824 | |
| 2825 | case DEFER: |
| 2826 | s = string_sprintf("435 Unable to authenticate at present%s", |
| 2827 | auth_defer_user_msg); |
| 2828 | ss = string_sprintf("435 Unable to authenticate at present%s: %s", |
| 2829 | set_id, auth_defer_msg); |
| 2830 | break; |
| 2831 | |
| 2832 | case BAD64: |
| 2833 | s = ss = US"501 Invalid base64 data"; |
| 2834 | break; |
| 2835 | |
| 2836 | case CANCELLED: |
| 2837 | s = ss = US"501 Authentication cancelled"; |
| 2838 | break; |
| 2839 | |
| 2840 | case UNEXPECTED: |
| 2841 | s = ss = US"553 Initial data not expected"; |
| 2842 | break; |
| 2843 | |
| 2844 | case FAIL: |
| 2845 | s = US"535 Incorrect authentication data"; |
| 2846 | ss = string_sprintf("535 Incorrect authentication data%s", set_id); |
| 2847 | break; |
| 2848 | |
| 2849 | default: |
| 2850 | s = US"435 Internal error"; |
| 2851 | ss = string_sprintf("435 Internal error%s: return %d from authentication " |
| 2852 | "check", set_id, c); |
| 2853 | break; |
| 2854 | } |
| 2855 | |
| 2856 | smtp_printf("%s\r\n", s); |
| 2857 | if (c != OK) |
| 2858 | log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s", |
| 2859 | au->name, host_and_ident(FALSE), ss); |
| 2860 | |
| 2861 | break; /* AUTH_CMD */ |
| 2862 | |
| 2863 | /* The HELO/EHLO commands are permitted to appear in the middle of a |
| 2864 | session as well as at the beginning. They have the effect of a reset in |
| 2865 | addition to their other functions. Their absence at the start cannot be |
| 2866 | taken to be an error. |
| 2867 | |
| 2868 | RFC 2821 says: |
| 2869 | |
| 2870 | If the EHLO command is not acceptable to the SMTP server, 501, 500, |
| 2871 | or 502 failure replies MUST be returned as appropriate. The SMTP |
| 2872 | server MUST stay in the same state after transmitting these replies |
| 2873 | that it was in before the EHLO was received. |
| 2874 | |
| 2875 | Therefore, we do not do the reset until after checking the command for |
| 2876 | acceptability. This change was made for Exim release 4.11. Previously |
| 2877 | it did the reset first. */ |
| 2878 | |
| 2879 | case HELO_CMD: |
| 2880 | HAD(SCH_HELO); |
| 2881 | hello = US"HELO"; |
| 2882 | esmtp = FALSE; |
| 2883 | goto HELO_EHLO; |
| 2884 | |
| 2885 | case EHLO_CMD: |
| 2886 | HAD(SCH_EHLO); |
| 2887 | hello = US"EHLO"; |
| 2888 | esmtp = TRUE; |
| 2889 | |
| 2890 | HELO_EHLO: /* Common code for HELO and EHLO */ |
| 2891 | cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE; |
| 2892 | cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE; |
| 2893 | |
| 2894 | /* Reject the HELO if its argument was invalid or non-existent. A |
| 2895 | successful check causes the argument to be saved in malloc store. */ |
| 2896 | |
| 2897 | if (!check_helo(smtp_cmd_data)) |
| 2898 | { |
| 2899 | smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello); |
| 2900 | |
| 2901 | log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically " |
| 2902 | "invalid argument(s): %s", hello, host_and_ident(FALSE), |
| 2903 | (*smtp_cmd_argument == 0)? US"(no argument given)" : |
| 2904 | string_printing(smtp_cmd_argument)); |
| 2905 | |
| 2906 | if (++synprot_error_count > smtp_max_synprot_errors) |
| 2907 | { |
| 2908 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " |
| 2909 | "syntax or protocol errors (last command was \"%s\")", |
| 2910 | host_and_ident(FALSE), smtp_cmd_buffer); |
| 2911 | done = 1; |
| 2912 | } |
| 2913 | |
| 2914 | break; |
| 2915 | } |
| 2916 | |
| 2917 | /* If sender_host_unknown is true, we have got here via the -bs interface, |
| 2918 | not called from inetd. Otherwise, we are running an IP connection and the |
| 2919 | host address will be set. If the helo name is the primary name of this |
| 2920 | host and we haven't done a reverse lookup, force one now. If helo_required |
| 2921 | is set, ensure that the HELO name matches the actual host. If helo_verify |
| 2922 | is set, do the same check, but softly. */ |
| 2923 | |
| 2924 | if (!sender_host_unknown) |
| 2925 | { |
| 2926 | BOOL old_helo_verified = helo_verified; |
| 2927 | uschar *p = smtp_cmd_data; |
| 2928 | |
| 2929 | while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; } |
| 2930 | *p = 0; |
| 2931 | |
| 2932 | /* Force a reverse lookup if HELO quoted something in helo_lookup_domains |
| 2933 | because otherwise the log can be confusing. */ |
| 2934 | |
| 2935 | if (sender_host_name == NULL && |
| 2936 | (deliver_domain = sender_helo_name, /* set $domain */ |
| 2937 | match_isinlist(sender_helo_name, &helo_lookup_domains, 0, |
| 2938 | &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK) |
| 2939 | (void)host_name_lookup(); |
| 2940 | |
| 2941 | /* Rebuild the fullhost info to include the HELO name (and the real name |
| 2942 | if it was looked up.) */ |
| 2943 | |
| 2944 | host_build_sender_fullhost(); /* Rebuild */ |
| 2945 | set_process_info("handling%s incoming connection from %s", |
| 2946 | (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE)); |
| 2947 | |
| 2948 | /* Verify if configured. This doesn't give much security, but it does |
| 2949 | make some people happy to be able to do it. If helo_required is set, |
| 2950 | (host matches helo_verify_hosts) failure forces rejection. If helo_verify |
| 2951 | is set (host matches helo_try_verify_hosts), it does not. This is perhaps |
| 2952 | now obsolescent, since the verification can now be requested selectively |
| 2953 | at ACL time. */ |
| 2954 | |
| 2955 | helo_verified = helo_verify_failed = FALSE; |
| 2956 | if (helo_required || helo_verify) |
| 2957 | { |
| 2958 | BOOL tempfail = !smtp_verify_helo(); |
| 2959 | if (!helo_verified) |
| 2960 | { |
| 2961 | if (helo_required) |
| 2962 | { |
| 2963 | smtp_printf("%d %s argument does not match calling host\r\n", |
| 2964 | tempfail? 451 : 550, hello); |
| 2965 | log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s", |
| 2966 | tempfail? "temporarily " : "", |
| 2967 | hello, sender_helo_name, host_and_ident(FALSE)); |
| 2968 | helo_verified = old_helo_verified; |
| 2969 | break; /* End of HELO/EHLO processing */ |
| 2970 | } |
| 2971 | HDEBUG(D_all) debug_printf("%s verification failed but host is in " |
| 2972 | "helo_try_verify_hosts\n", hello); |
| 2973 | } |
| 2974 | } |
| 2975 | } |
| 2976 | |
| 2977 | #ifdef EXPERIMENTAL_SPF |
| 2978 | /* set up SPF context */ |
| 2979 | spf_init(sender_helo_name, sender_host_address); |
| 2980 | #endif |
| 2981 | |
| 2982 | /* Apply an ACL check if one is defined; afterwards, recheck |
| 2983 | synchronization in case the client started sending in a delay. */ |
| 2984 | |
| 2985 | if (acl_smtp_helo != NULL) |
| 2986 | { |
| 2987 | rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg); |
| 2988 | if (rc != OK) |
| 2989 | { |
| 2990 | done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg); |
| 2991 | sender_helo_name = NULL; |
| 2992 | host_build_sender_fullhost(); /* Rebuild */ |
| 2993 | break; |
| 2994 | } |
| 2995 | else if (!check_sync()) goto SYNC_FAILURE; |
| 2996 | } |
| 2997 | |
| 2998 | /* Generate an OK reply. The default string includes the ident if present, |
| 2999 | and also the IP address if present. Reflecting back the ident is intended |
| 3000 | as a deterrent to mail forgers. For maximum efficiency, and also because |
| 3001 | some broken systems expect each response to be in a single packet, arrange |
| 3002 | that the entire reply is sent in one write(). */ |
| 3003 | |
| 3004 | auth_advertised = FALSE; |
| 3005 | pipelining_advertised = FALSE; |
| 3006 | #ifdef SUPPORT_TLS |
| 3007 | tls_advertised = FALSE; |
| 3008 | #endif |
| 3009 | |
| 3010 | smtp_code = US"250 "; /* Default response code plus space*/ |
| 3011 | if (user_msg == NULL) |
| 3012 | { |
| 3013 | s = string_sprintf("%.3s %s Hello %s%s%s", |
| 3014 | smtp_code, |
| 3015 | smtp_active_hostname, |
| 3016 | (sender_ident == NULL)? US"" : sender_ident, |
| 3017 | (sender_ident == NULL)? US"" : US" at ", |
| 3018 | (sender_host_name == NULL)? sender_helo_name : sender_host_name); |
| 3019 | |
| 3020 | ptr = Ustrlen(s); |
| 3021 | size = ptr + 1; |
| 3022 | |
| 3023 | if (sender_host_address != NULL) |
| 3024 | { |
| 3025 | s = string_cat(s, &size, &ptr, US" [", 2); |
| 3026 | s = string_cat(s, &size, &ptr, sender_host_address, |
| 3027 | Ustrlen(sender_host_address)); |
| 3028 | s = string_cat(s, &size, &ptr, US"]", 1); |
| 3029 | } |
| 3030 | } |
| 3031 | |
| 3032 | /* A user-supplied EHLO greeting may not contain more than one line. Note |
| 3033 | that the code returned by smtp_message_code() includes the terminating |
| 3034 | whitespace character. */ |
| 3035 | |
| 3036 | else |
| 3037 | { |
| 3038 | char *ss; |
| 3039 | int codelen = 4; |
| 3040 | smtp_message_code(&smtp_code, &codelen, &user_msg, NULL); |
| 3041 | s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg); |
| 3042 | if ((ss = strpbrk(CS s, "\r\n")) != NULL) |
| 3043 | { |
| 3044 | log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain " |
| 3045 | "newlines: message truncated: %s", string_printing(s)); |
| 3046 | *ss = 0; |
| 3047 | } |
| 3048 | ptr = Ustrlen(s); |
| 3049 | size = ptr + 1; |
| 3050 | } |
| 3051 | |
| 3052 | s = string_cat(s, &size, &ptr, US"\r\n", 2); |
| 3053 | |
| 3054 | /* If we received EHLO, we must create a multiline response which includes |
| 3055 | the functions supported. */ |
| 3056 | |
| 3057 | if (esmtp) |
| 3058 | { |
| 3059 | s[3] = '-'; |
| 3060 | |
| 3061 | /* I'm not entirely happy with this, as an MTA is supposed to check |
| 3062 | that it has enough room to accept a message of maximum size before |
| 3063 | it sends this. However, there seems little point in not sending it. |
| 3064 | The actual size check happens later at MAIL FROM time. By postponing it |
| 3065 | till then, VRFY and EXPN can be used after EHLO when space is short. */ |
| 3066 | |
| 3067 | if (thismessage_size_limit > 0) |
| 3068 | { |
| 3069 | sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code, |
| 3070 | thismessage_size_limit); |
| 3071 | s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer)); |
| 3072 | } |
| 3073 | else |
| 3074 | { |
| 3075 | s = string_cat(s, &size, &ptr, smtp_code, 3); |
| 3076 | s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7); |
| 3077 | } |
| 3078 | |
| 3079 | /* Exim does not do protocol conversion or data conversion. It is 8-bit |
| 3080 | clean; if it has an 8-bit character in its hand, it just sends it. It |
| 3081 | cannot therefore specify 8BITMIME and remain consistent with the RFCs. |
| 3082 | However, some users want this option simply in order to stop MUAs |
| 3083 | mangling messages that contain top-bit-set characters. It is therefore |
| 3084 | provided as an option. */ |
| 3085 | |
| 3086 | if (accept_8bitmime) |
| 3087 | { |
| 3088 | s = string_cat(s, &size, &ptr, smtp_code, 3); |
| 3089 | s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11); |
| 3090 | } |
| 3091 | |
| 3092 | /* Advertise ETRN if there's an ACL checking whether a host is |
| 3093 | permitted to issue it; a check is made when any host actually tries. */ |
| 3094 | |
| 3095 | if (acl_smtp_etrn != NULL) |
| 3096 | { |
| 3097 | s = string_cat(s, &size, &ptr, smtp_code, 3); |
| 3098 | s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7); |
| 3099 | } |
| 3100 | |
| 3101 | /* Advertise EXPN if there's an ACL checking whether a host is |
| 3102 | permitted to issue it; a check is made when any host actually tries. */ |
| 3103 | |
| 3104 | if (acl_smtp_expn != NULL) |
| 3105 | { |
| 3106 | s = string_cat(s, &size, &ptr, smtp_code, 3); |
| 3107 | s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7); |
| 3108 | } |
| 3109 | |
| 3110 | /* Exim is quite happy with pipelining, so let the other end know that |
| 3111 | it is safe to use it, unless advertising is disabled. */ |
| 3112 | |
| 3113 | if (pipelining_enable && |
| 3114 | verify_check_host(&pipelining_advertise_hosts) == OK) |
| 3115 | { |
| 3116 | s = string_cat(s, &size, &ptr, smtp_code, 3); |
| 3117 | s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13); |
| 3118 | sync_cmd_limit = NON_SYNC_CMD_PIPELINING; |
| 3119 | pipelining_advertised = TRUE; |
| 3120 | } |
| 3121 | |
| 3122 | /* If any server authentication mechanisms are configured, advertise |
| 3123 | them if the current host is in auth_advertise_hosts. The problem with |
| 3124 | advertising always is that some clients then require users to |
| 3125 | authenticate (and aren't configurable otherwise) even though it may not |
| 3126 | be necessary (e.g. if the host is in host_accept_relay). |
| 3127 | |
| 3128 | RFC 2222 states that SASL mechanism names contain only upper case |
| 3129 | letters, so output the names in upper case, though we actually recognize |
| 3130 | them in either case in the AUTH command. */ |
| 3131 | |
| 3132 | if (auths != NULL) |
| 3133 | { |
| 3134 | if (verify_check_host(&auth_advertise_hosts) == OK) |
| 3135 | { |
| 3136 | auth_instance *au; |
| 3137 | BOOL first = TRUE; |
| 3138 | for (au = auths; au != NULL; au = au->next) |
| 3139 | { |
| 3140 | if (au->server && (au->advertise_condition == NULL || |
| 3141 | expand_check_condition(au->advertise_condition, au->name, |
| 3142 | US"authenticator"))) |
| 3143 | { |
| 3144 | int saveptr; |
| 3145 | if (first) |
| 3146 | { |
| 3147 | s = string_cat(s, &size, &ptr, smtp_code, 3); |
| 3148 | s = string_cat(s, &size, &ptr, US"-AUTH", 5); |
| 3149 | first = FALSE; |
| 3150 | auth_advertised = TRUE; |
| 3151 | } |
| 3152 | saveptr = ptr; |
| 3153 | s = string_cat(s, &size, &ptr, US" ", 1); |
| 3154 | s = string_cat(s, &size, &ptr, au->public_name, |
| 3155 | Ustrlen(au->public_name)); |
| 3156 | while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]); |
| 3157 | au->advertised = TRUE; |
| 3158 | } |
| 3159 | else au->advertised = FALSE; |
| 3160 | } |
| 3161 | if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2); |
| 3162 | } |
| 3163 | } |
| 3164 | |
| 3165 | /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer) |
| 3166 | if it has been included in the binary, and the host matches |
| 3167 | tls_advertise_hosts. We must *not* advertise if we are already in a |
| 3168 | secure connection. */ |
| 3169 | |
| 3170 | #ifdef SUPPORT_TLS |
| 3171 | if (tls_in.active < 0 && |
| 3172 | verify_check_host(&tls_advertise_hosts) != FAIL) |
| 3173 | { |
| 3174 | s = string_cat(s, &size, &ptr, smtp_code, 3); |
| 3175 | s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11); |
| 3176 | tls_advertised = TRUE; |
| 3177 | } |
| 3178 | #endif |
| 3179 | |
| 3180 | /* Finish off the multiline reply with one that is always available. */ |
| 3181 | |
| 3182 | s = string_cat(s, &size, &ptr, smtp_code, 3); |
| 3183 | s = string_cat(s, &size, &ptr, US" HELP\r\n", 7); |
| 3184 | } |
| 3185 | |
| 3186 | /* Terminate the string (for debug), write it, and note that HELO/EHLO |
| 3187 | has been seen. */ |
| 3188 | |
| 3189 | s[ptr] = 0; |
| 3190 | |
| 3191 | #ifdef SUPPORT_TLS |
| 3192 | if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else |
| 3193 | #endif |
| 3194 | |
| 3195 | { |
| 3196 | int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */ |
| 3197 | } |
| 3198 | DEBUG(D_receive) |
| 3199 | { |
| 3200 | uschar *cr; |
| 3201 | while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */ |
| 3202 | memmove(cr, cr + 1, (ptr--) - (cr - s)); |
| 3203 | debug_printf("SMTP>> %s", s); |
| 3204 | } |
| 3205 | helo_seen = TRUE; |
| 3206 | |
| 3207 | /* Reset the protocol and the state, abandoning any previous message. */ |
| 3208 | |
| 3209 | received_protocol = (esmtp? |
| 3210 | protocols[pextend + |
| 3211 | ((sender_host_authenticated != NULL)? pauthed : 0) + |
| 3212 | ((tls_in.active >= 0)? pcrpted : 0)] |
| 3213 | : |
| 3214 | protocols[pnormal + ((tls_in.active >= 0)? pcrpted : 0)]) |
| 3215 | + |
| 3216 | ((sender_host_address != NULL)? pnlocal : 0); |
| 3217 | |
| 3218 | smtp_reset(reset_point); |
| 3219 | toomany = FALSE; |
| 3220 | break; /* HELO/EHLO */ |
| 3221 | |
| 3222 | |
| 3223 | /* The MAIL command requires an address as an operand. All we do |
| 3224 | here is to parse it for syntactic correctness. The form "<>" is |
| 3225 | a special case which converts into an empty string. The start/end |
| 3226 | pointers in the original are not used further for this address, as |
| 3227 | it is the canonical extracted address which is all that is kept. */ |
| 3228 | |
| 3229 | case MAIL_CMD: |
| 3230 | HAD(SCH_MAIL); |
| 3231 | smtp_mailcmd_count++; /* Count for limit and ratelimit */ |
| 3232 | was_rej_mail = TRUE; /* Reset if accepted */ |
| 3233 | env_mail_type_t * mail_args; /* Sanity check & validate args */ |
| 3234 | |
| 3235 | if (helo_required && !helo_seen) |
| 3236 | { |
| 3237 | smtp_printf("503 HELO or EHLO required\r\n"); |
| 3238 | log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no " |
| 3239 | "HELO/EHLO given", host_and_ident(FALSE)); |
| 3240 | break; |
| 3241 | } |
| 3242 | |
| 3243 | if (sender_address != NULL) |
| 3244 | { |
| 3245 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 3246 | US"sender already given"); |
| 3247 | break; |
| 3248 | } |
| 3249 | |
| 3250 | if (smtp_cmd_data[0] == 0) |
| 3251 | { |
| 3252 | done = synprot_error(L_smtp_protocol_error, 501, NULL, |
| 3253 | US"MAIL must have an address operand"); |
| 3254 | break; |
| 3255 | } |
| 3256 | |
| 3257 | /* Check to see if the limit for messages per connection would be |
| 3258 | exceeded by accepting further messages. */ |
| 3259 | |
| 3260 | if (smtp_accept_max_per_connection > 0 && |
| 3261 | smtp_mailcmd_count > smtp_accept_max_per_connection) |
| 3262 | { |
| 3263 | smtp_printf("421 too many messages in this connection\r\n"); |
| 3264 | log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many " |
| 3265 | "messages in one connection", host_and_ident(TRUE)); |
| 3266 | break; |
| 3267 | } |
| 3268 | |
| 3269 | /* Reset for start of message - even if this is going to fail, we |
| 3270 | obviously need to throw away any previous data. */ |
| 3271 | |
| 3272 | smtp_reset(reset_point); |
| 3273 | toomany = FALSE; |
| 3274 | sender_data = recipient_data = NULL; |
| 3275 | |
| 3276 | /* Loop, checking for ESMTP additions to the MAIL FROM command. */ |
| 3277 | |
| 3278 | if (esmtp) for(;;) |
| 3279 | { |
| 3280 | uschar *name, *value, *end; |
| 3281 | unsigned long int size; |
| 3282 | BOOL arg_error = FALSE; |
| 3283 | |
| 3284 | if (!extract_option(&name, &value)) break; |
| 3285 | |
| 3286 | for (mail_args = env_mail_type_list; |
| 3287 | (char *)mail_args < (char *)env_mail_type_list + sizeof(env_mail_type_list); |
| 3288 | mail_args++ |
| 3289 | ) |
| 3290 | { |
| 3291 | if (strcmpic(name, mail_args->name) == 0) |
| 3292 | break; |
| 3293 | } |
| 3294 | if (mail_args->need_value && strcmpic(value, US"") == 0) |
| 3295 | break; |
| 3296 | /* This doesn't seem right to use |
| 3297 | if ((char *)mail_args >= (char *)env_mail_type_list + sizeof(env_mail_type_list)) |
| 3298 | goto BAD_MAIL_ARGS; |
| 3299 | */ |
| 3300 | |
| 3301 | switch(mail_args->value) |
| 3302 | { |
| 3303 | /* Handle SIZE= by reading the value. We don't do the check till later, |
| 3304 | in order to be able to log the sender address on failure. */ |
| 3305 | case ENV_MAIL_OPT_SIZE: |
| 3306 | /* if (strcmpic(name, US"SIZE") == 0 && */ |
| 3307 | if (((size = Ustrtoul(value, &end, 10)), *end == 0)) |
| 3308 | { |
| 3309 | if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX) |
| 3310 | size = INT_MAX; |
| 3311 | message_size = (int)size; |
| 3312 | } |
| 3313 | else |
| 3314 | arg_error = TRUE; |
| 3315 | break; |
| 3316 | |
| 3317 | /* If this session was initiated with EHLO and accept_8bitmime is set, |
| 3318 | Exim will have indicated that it supports the BODY=8BITMIME option. In |
| 3319 | fact, it does not support this according to the RFCs, in that it does not |
| 3320 | take any special action for forwarding messages containing 8-bit |
| 3321 | characters. That is why accept_8bitmime is not the default setting, but |
| 3322 | some sites want the action that is provided. We recognize both "8BITMIME" |
| 3323 | and "7BIT" as body types, but take no action. */ |
| 3324 | case ENV_MAIL_OPT_BODY: |
| 3325 | if (accept_8bitmime) { |
| 3326 | if (strcmpic(value, US"8BITMIME") == 0) { |
| 3327 | body_8bitmime = 8; |
| 3328 | } else if (strcmpic(value, US"7BIT") == 0) { |
| 3329 | body_8bitmime = 7; |
| 3330 | } else { |
| 3331 | body_8bitmime = 0; |
| 3332 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 3333 | US"invalid data for BODY"); |
| 3334 | goto COMMAND_LOOP; |
| 3335 | } |
| 3336 | DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime); |
| 3337 | break; |
| 3338 | } |
| 3339 | arg_error = TRUE; |
| 3340 | break; |
| 3341 | |
| 3342 | /* Handle the AUTH extension. If the value given is not "<>" and either |
| 3343 | the ACL says "yes" or there is no ACL but the sending host is |
| 3344 | authenticated, we set it up as the authenticated sender. However, if the |
| 3345 | authenticator set a condition to be tested, we ignore AUTH on MAIL unless |
| 3346 | the condition is met. The value of AUTH is an xtext, which means that +, |
| 3347 | = and cntrl chars are coded in hex; however "<>" is unaffected by this |
| 3348 | coding. */ |
| 3349 | case ENV_MAIL_OPT_AUTH: |
| 3350 | if (Ustrcmp(value, "<>") != 0) |
| 3351 | { |
| 3352 | int rc; |
| 3353 | uschar *ignore_msg; |
| 3354 | |
| 3355 | if (auth_xtextdecode(value, &authenticated_sender) < 0) |
| 3356 | { |
| 3357 | /* Put back terminator overrides for error message */ |
| 3358 | name[-1] = ' '; |
| 3359 | value[-1] = '='; |
| 3360 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 3361 | US"invalid data for AUTH"); |
| 3362 | goto COMMAND_LOOP; |
| 3363 | } |
| 3364 | if (acl_smtp_mailauth == NULL) |
| 3365 | { |
| 3366 | ignore_msg = US"client not authenticated"; |
| 3367 | rc = (sender_host_authenticated != NULL)? OK : FAIL; |
| 3368 | } |
| 3369 | else |
| 3370 | { |
| 3371 | ignore_msg = US"rejected by ACL"; |
| 3372 | rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth, |
| 3373 | &user_msg, &log_msg); |
| 3374 | } |
| 3375 | |
| 3376 | switch (rc) |
| 3377 | { |
| 3378 | case OK: |
| 3379 | if (authenticated_by == NULL || |
| 3380 | authenticated_by->mail_auth_condition == NULL || |
| 3381 | expand_check_condition(authenticated_by->mail_auth_condition, |
| 3382 | authenticated_by->name, US"authenticator")) |
| 3383 | break; /* Accept the AUTH */ |
| 3384 | |
| 3385 | ignore_msg = US"server_mail_auth_condition failed"; |
| 3386 | if (authenticated_id != NULL) |
| 3387 | ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"", |
| 3388 | ignore_msg, authenticated_id); |
| 3389 | |
| 3390 | /* Fall through */ |
| 3391 | |
| 3392 | case FAIL: |
| 3393 | authenticated_sender = NULL; |
| 3394 | log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)", |
| 3395 | value, host_and_ident(TRUE), ignore_msg); |
| 3396 | break; |
| 3397 | |
| 3398 | /* Should only get DEFER or ERROR here. Put back terminator |
| 3399 | overrides for error message */ |
| 3400 | |
| 3401 | default: |
| 3402 | name[-1] = ' '; |
| 3403 | value[-1] = '='; |
| 3404 | (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg, |
| 3405 | log_msg); |
| 3406 | goto COMMAND_LOOP; |
| 3407 | } |
| 3408 | } |
| 3409 | break; |
| 3410 | |
| 3411 | /* Unknown option. Stick back the terminator characters and break |
| 3412 | the loop. An error for a malformed address will occur. */ |
| 3413 | default: |
| 3414 | |
| 3415 | /* BAD_MAIL_ARGS: */ |
| 3416 | name[-1] = ' '; |
| 3417 | value[-1] = '='; |
| 3418 | break; |
| 3419 | } |
| 3420 | /* Break out of for loop if switch() had bad argument or |
| 3421 | when start of the email address is reached */ |
| 3422 | if (arg_error) break; |
| 3423 | } |
| 3424 | |
| 3425 | /* If we have passed the threshold for rate limiting, apply the current |
| 3426 | delay, and update it for next time, provided this is a limited host. */ |
| 3427 | |
| 3428 | if (smtp_mailcmd_count > smtp_rlm_threshold && |
| 3429 | verify_check_host(&smtp_ratelimit_hosts) == OK) |
| 3430 | { |
| 3431 | DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n", |
| 3432 | smtp_delay_mail/1000.0); |
| 3433 | millisleep((int)smtp_delay_mail); |
| 3434 | smtp_delay_mail *= smtp_rlm_factor; |
| 3435 | if (smtp_delay_mail > (double)smtp_rlm_limit) |
| 3436 | smtp_delay_mail = (double)smtp_rlm_limit; |
| 3437 | } |
| 3438 | |
| 3439 | /* Now extract the address, first applying any SMTP-time rewriting. The |
| 3440 | TRUE flag allows "<>" as a sender address. */ |
| 3441 | |
| 3442 | raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)? |
| 3443 | rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"", |
| 3444 | global_rewrite_rules) : smtp_cmd_data; |
| 3445 | |
| 3446 | /* rfc821_domains = TRUE; << no longer needed */ |
| 3447 | raw_sender = |
| 3448 | parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain, |
| 3449 | TRUE); |
| 3450 | /* rfc821_domains = FALSE; << no longer needed */ |
| 3451 | |
| 3452 | if (raw_sender == NULL) |
| 3453 | { |
| 3454 | done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess); |
| 3455 | break; |
| 3456 | } |
| 3457 | |
| 3458 | sender_address = raw_sender; |
| 3459 | |
| 3460 | /* If there is a configured size limit for mail, check that this message |
| 3461 | doesn't exceed it. The check is postponed to this point so that the sender |
| 3462 | can be logged. */ |
| 3463 | |
| 3464 | if (thismessage_size_limit > 0 && message_size > thismessage_size_limit) |
| 3465 | { |
| 3466 | smtp_printf("552 Message size exceeds maximum permitted\r\n"); |
| 3467 | log_write(L_size_reject, |
| 3468 | LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: " |
| 3469 | "message too big: size%s=%d max=%d", |
| 3470 | sender_address, |
| 3471 | host_and_ident(TRUE), |
| 3472 | (message_size == INT_MAX)? ">" : "", |
| 3473 | message_size, |
| 3474 | thismessage_size_limit); |
| 3475 | sender_address = NULL; |
| 3476 | break; |
| 3477 | } |
| 3478 | |
| 3479 | /* Check there is enough space on the disk unless configured not to. |
| 3480 | When smtp_check_spool_space is set, the check is for thismessage_size_limit |
| 3481 | plus the current message - i.e. we accept the message only if it won't |
| 3482 | reduce the space below the threshold. Add 5000 to the size to allow for |
| 3483 | overheads such as the Received: line and storing of recipients, etc. |
| 3484 | By putting the check here, even when SIZE is not given, it allow VRFY |
| 3485 | and EXPN etc. to be used when space is short. */ |
| 3486 | |
| 3487 | if (!receive_check_fs( |
| 3488 | (smtp_check_spool_space && message_size >= 0)? |
| 3489 | message_size + 5000 : 0)) |
| 3490 | { |
| 3491 | smtp_printf("452 Space shortage, please try later\r\n"); |
| 3492 | sender_address = NULL; |
| 3493 | break; |
| 3494 | } |
| 3495 | |
| 3496 | /* If sender_address is unqualified, reject it, unless this is a locally |
| 3497 | generated message, or the sending host or net is permitted to send |
| 3498 | unqualified addresses - typically local machines behaving as MUAs - |
| 3499 | in which case just qualify the address. The flag is set above at the start |
| 3500 | of the SMTP connection. */ |
| 3501 | |
| 3502 | if (sender_domain == 0 && sender_address[0] != 0) |
| 3503 | { |
| 3504 | if (allow_unqualified_sender) |
| 3505 | { |
| 3506 | sender_domain = Ustrlen(sender_address) + 1; |
| 3507 | sender_address = rewrite_address_qualify(sender_address, FALSE); |
| 3508 | DEBUG(D_receive) debug_printf("unqualified address %s accepted\n", |
| 3509 | raw_sender); |
| 3510 | } |
| 3511 | else |
| 3512 | { |
| 3513 | smtp_printf("501 %s: sender address must contain a domain\r\n", |
| 3514 | smtp_cmd_data); |
| 3515 | log_write(L_smtp_syntax_error, |
| 3516 | LOG_MAIN|LOG_REJECT, |
| 3517 | "unqualified sender rejected: <%s> %s%s", |
| 3518 | raw_sender, |
| 3519 | host_and_ident(TRUE), |
| 3520 | host_lookup_msg); |
| 3521 | sender_address = NULL; |
| 3522 | break; |
| 3523 | } |
| 3524 | } |
| 3525 | |
| 3526 | /* Apply an ACL check if one is defined, before responding. Afterwards, |
| 3527 | when pipelining is not advertised, do another sync check in case the ACL |
| 3528 | delayed and the client started sending in the meantime. */ |
| 3529 | |
| 3530 | if (acl_smtp_mail == NULL) rc = OK; else |
| 3531 | { |
| 3532 | rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg); |
| 3533 | if (rc == OK && !pipelining_advertised && !check_sync()) |
| 3534 | goto SYNC_FAILURE; |
| 3535 | } |
| 3536 | |
| 3537 | if (rc == OK || rc == DISCARD) |
| 3538 | { |
| 3539 | if (user_msg == NULL) smtp_printf("250 OK\r\n"); |
| 3540 | else smtp_user_msg(US"250", user_msg); |
| 3541 | smtp_delay_rcpt = smtp_rlr_base; |
| 3542 | recipients_discarded = (rc == DISCARD); |
| 3543 | was_rej_mail = FALSE; |
| 3544 | } |
| 3545 | else |
| 3546 | { |
| 3547 | done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg); |
| 3548 | sender_address = NULL; |
| 3549 | } |
| 3550 | break; |
| 3551 | |
| 3552 | |
| 3553 | /* The RCPT command requires an address as an operand. There may be any |
| 3554 | number of RCPT commands, specifying multiple recipients. We build them all |
| 3555 | into a data structure. The start/end values given by parse_extract_address |
| 3556 | are not used, as we keep only the extracted address. */ |
| 3557 | |
| 3558 | case RCPT_CMD: |
| 3559 | HAD(SCH_RCPT); |
| 3560 | rcpt_count++; |
| 3561 | was_rcpt = rcpt_in_progress = TRUE; |
| 3562 | |
| 3563 | /* There must be a sender address; if the sender was rejected and |
| 3564 | pipelining was advertised, we assume the client was pipelining, and do not |
| 3565 | count this as a protocol error. Reset was_rej_mail so that further RCPTs |
| 3566 | get the same treatment. */ |
| 3567 | |
| 3568 | if (sender_address == NULL) |
| 3569 | { |
| 3570 | if (pipelining_advertised && last_was_rej_mail) |
| 3571 | { |
| 3572 | smtp_printf("503 sender not yet given\r\n"); |
| 3573 | was_rej_mail = TRUE; |
| 3574 | } |
| 3575 | else |
| 3576 | { |
| 3577 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 3578 | US"sender not yet given"); |
| 3579 | was_rcpt = FALSE; /* Not a valid RCPT */ |
| 3580 | } |
| 3581 | rcpt_fail_count++; |
| 3582 | break; |
| 3583 | } |
| 3584 | |
| 3585 | /* Check for an operand */ |
| 3586 | |
| 3587 | if (smtp_cmd_data[0] == 0) |
| 3588 | { |
| 3589 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 3590 | US"RCPT must have an address operand"); |
| 3591 | rcpt_fail_count++; |
| 3592 | break; |
| 3593 | } |
| 3594 | |
| 3595 | /* Apply SMTP rewriting then extract the working address. Don't allow "<>" |
| 3596 | as a recipient address */ |
| 3597 | |
| 3598 | recipient = ((rewrite_existflags & rewrite_smtp) != 0)? |
| 3599 | rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"", |
| 3600 | global_rewrite_rules) : smtp_cmd_data; |
| 3601 | |
| 3602 | /* rfc821_domains = TRUE; << no longer needed */ |
| 3603 | recipient = parse_extract_address(recipient, &errmess, &start, &end, |
| 3604 | &recipient_domain, FALSE); |
| 3605 | /* rfc821_domains = FALSE; << no longer needed */ |
| 3606 | |
| 3607 | if (recipient == NULL) |
| 3608 | { |
| 3609 | done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess); |
| 3610 | rcpt_fail_count++; |
| 3611 | break; |
| 3612 | } |
| 3613 | |
| 3614 | /* If the recipient address is unqualified, reject it, unless this is a |
| 3615 | locally generated message. However, unqualified addresses are permitted |
| 3616 | from a configured list of hosts and nets - typically when behaving as |
| 3617 | MUAs rather than MTAs. Sad that SMTP is used for both types of traffic, |
| 3618 | really. The flag is set at the start of the SMTP connection. |
| 3619 | |
| 3620 | RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always |
| 3621 | assumed this meant "reserved local part", but the revision of RFC 821 and |
| 3622 | friends now makes it absolutely clear that it means *mailbox*. Consequently |
| 3623 | we must always qualify this address, regardless. */ |
| 3624 | |
| 3625 | if (recipient_domain == 0) |
| 3626 | { |
| 3627 | if (allow_unqualified_recipient || |
| 3628 | strcmpic(recipient, US"postmaster") == 0) |
| 3629 | { |
| 3630 | DEBUG(D_receive) debug_printf("unqualified address %s accepted\n", |
| 3631 | recipient); |
| 3632 | recipient_domain = Ustrlen(recipient) + 1; |
| 3633 | recipient = rewrite_address_qualify(recipient, TRUE); |
| 3634 | } |
| 3635 | else |
| 3636 | { |
| 3637 | rcpt_fail_count++; |
| 3638 | smtp_printf("501 %s: recipient address must contain a domain\r\n", |
| 3639 | smtp_cmd_data); |
| 3640 | log_write(L_smtp_syntax_error, |
| 3641 | LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: " |
| 3642 | "<%s> %s%s", recipient, host_and_ident(TRUE), |
| 3643 | host_lookup_msg); |
| 3644 | break; |
| 3645 | } |
| 3646 | } |
| 3647 | |
| 3648 | /* Check maximum allowed */ |
| 3649 | |
| 3650 | if (rcpt_count > recipients_max && recipients_max > 0) |
| 3651 | { |
| 3652 | if (recipients_max_reject) |
| 3653 | { |
| 3654 | rcpt_fail_count++; |
| 3655 | smtp_printf("552 too many recipients\r\n"); |
| 3656 | if (!toomany) |
| 3657 | log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message " |
| 3658 | "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE)); |
| 3659 | } |
| 3660 | else |
| 3661 | { |
| 3662 | rcpt_defer_count++; |
| 3663 | smtp_printf("452 too many recipients\r\n"); |
| 3664 | if (!toomany) |
| 3665 | log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess " |
| 3666 | "temporarily rejected: sender=<%s> %s", sender_address, |
| 3667 | host_and_ident(TRUE)); |
| 3668 | } |
| 3669 | |
| 3670 | toomany = TRUE; |
| 3671 | break; |
| 3672 | } |
| 3673 | |
| 3674 | /* If we have passed the threshold for rate limiting, apply the current |
| 3675 | delay, and update it for next time, provided this is a limited host. */ |
| 3676 | |
| 3677 | if (rcpt_count > smtp_rlr_threshold && |
| 3678 | verify_check_host(&smtp_ratelimit_hosts) == OK) |
| 3679 | { |
| 3680 | DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n", |
| 3681 | smtp_delay_rcpt/1000.0); |
| 3682 | millisleep((int)smtp_delay_rcpt); |
| 3683 | smtp_delay_rcpt *= smtp_rlr_factor; |
| 3684 | if (smtp_delay_rcpt > (double)smtp_rlr_limit) |
| 3685 | smtp_delay_rcpt = (double)smtp_rlr_limit; |
| 3686 | } |
| 3687 | |
| 3688 | /* If the MAIL ACL discarded all the recipients, we bypass ACL checking |
| 3689 | for them. Otherwise, check the access control list for this recipient. As |
| 3690 | there may be a delay in this, re-check for a synchronization error |
| 3691 | afterwards, unless pipelining was advertised. */ |
| 3692 | |
| 3693 | if (recipients_discarded) rc = DISCARD; else |
| 3694 | { |
| 3695 | rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, |
| 3696 | &log_msg); |
| 3697 | if (rc == OK && !pipelining_advertised && !check_sync()) |
| 3698 | goto SYNC_FAILURE; |
| 3699 | } |
| 3700 | |
| 3701 | /* The ACL was happy */ |
| 3702 | |
| 3703 | if (rc == OK) |
| 3704 | { |
| 3705 | if (user_msg == NULL) smtp_printf("250 Accepted\r\n"); |
| 3706 | else smtp_user_msg(US"250", user_msg); |
| 3707 | receive_add_recipient(recipient, -1); |
| 3708 | } |
| 3709 | |
| 3710 | /* The recipient was discarded */ |
| 3711 | |
| 3712 | else if (rc == DISCARD) |
| 3713 | { |
| 3714 | if (user_msg == NULL) smtp_printf("250 Accepted\r\n"); |
| 3715 | else smtp_user_msg(US"250", user_msg); |
| 3716 | rcpt_fail_count++; |
| 3717 | discarded = TRUE; |
| 3718 | log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: " |
| 3719 | "discarded by %s ACL%s%s", host_and_ident(TRUE), |
| 3720 | (sender_address_unrewritten != NULL)? |
| 3721 | sender_address_unrewritten : sender_address, |
| 3722 | smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT", |
| 3723 | (log_msg == NULL)? US"" : US": ", |
| 3724 | (log_msg == NULL)? US"" : log_msg); |
| 3725 | } |
| 3726 | |
| 3727 | /* Either the ACL failed the address, or it was deferred. */ |
| 3728 | |
| 3729 | else |
| 3730 | { |
| 3731 | if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++; |
| 3732 | done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg); |
| 3733 | } |
| 3734 | break; |
| 3735 | |
| 3736 | |
| 3737 | /* The DATA command is legal only if it follows successful MAIL FROM |
| 3738 | and RCPT TO commands. However, if pipelining is advertised, a bad DATA is |
| 3739 | not counted as a protocol error if it follows RCPT (which must have been |
| 3740 | rejected if there are no recipients.) This function is complete when a |
| 3741 | valid DATA command is encountered. |
| 3742 | |
| 3743 | Note concerning the code used: RFC 2821 says this: |
| 3744 | |
| 3745 | - If there was no MAIL, or no RCPT, command, or all such commands |
| 3746 | were rejected, the server MAY return a "command out of sequence" |
| 3747 | (503) or "no valid recipients" (554) reply in response to the |
| 3748 | DATA command. |
| 3749 | |
| 3750 | The example in the pipelining RFC 2920 uses 554, but I use 503 here |
| 3751 | because it is the same whether pipelining is in use or not. |
| 3752 | |
| 3753 | If all the RCPT commands that precede DATA provoked the same error message |
| 3754 | (often indicating some kind of system error), it is helpful to include it |
| 3755 | with the DATA rejection (an idea suggested by Tony Finch). */ |
| 3756 | |
| 3757 | case DATA_CMD: |
| 3758 | HAD(SCH_DATA); |
| 3759 | if (!discarded && recipients_count <= 0) |
| 3760 | { |
| 3761 | if (rcpt_smtp_response_same && rcpt_smtp_response != NULL) |
| 3762 | { |
| 3763 | uschar *code = US"503"; |
| 3764 | int len = Ustrlen(rcpt_smtp_response); |
| 3765 | smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with " |
| 3766 | "this error:"); |
| 3767 | /* Responses from smtp_printf() will have \r\n on the end */ |
| 3768 | if (len > 2 && rcpt_smtp_response[len-2] == '\r') |
| 3769 | rcpt_smtp_response[len-2] = 0; |
| 3770 | smtp_respond(code, 3, FALSE, rcpt_smtp_response); |
| 3771 | } |
| 3772 | if (pipelining_advertised && last_was_rcpt) |
| 3773 | smtp_printf("503 Valid RCPT command must precede DATA\r\n"); |
| 3774 | else |
| 3775 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 3776 | US"valid RCPT command must precede DATA"); |
| 3777 | break; |
| 3778 | } |
| 3779 | |
| 3780 | if (toomany && recipients_max_reject) |
| 3781 | { |
| 3782 | sender_address = NULL; /* This will allow a new MAIL without RSET */ |
| 3783 | sender_address_unrewritten = NULL; |
| 3784 | smtp_printf("554 Too many recipients\r\n"); |
| 3785 | break; |
| 3786 | } |
| 3787 | |
| 3788 | /* If there is an ACL, re-check the synchronization afterwards, since the |
| 3789 | ACL may have delayed. To handle cutthrough delivery enforce a dummy call |
| 3790 | to get the DATA command sent. */ |
| 3791 | |
| 3792 | if (acl_smtp_predata == NULL && cutthrough_fd < 0) rc = OK; else |
| 3793 | { |
| 3794 | uschar * acl= acl_smtp_predata ? acl_smtp_predata : US"accept"; |
| 3795 | enable_dollar_recipients = TRUE; |
| 3796 | rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg, |
| 3797 | &log_msg); |
| 3798 | enable_dollar_recipients = FALSE; |
| 3799 | if (rc == OK && !check_sync()) goto SYNC_FAILURE; |
| 3800 | } |
| 3801 | |
| 3802 | if (rc == OK) |
| 3803 | { |
| 3804 | if (user_msg == NULL) |
| 3805 | smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n"); |
| 3806 | else smtp_user_msg(US"354", user_msg); |
| 3807 | done = 3; |
| 3808 | message_ended = END_NOTENDED; /* Indicate in middle of data */ |
| 3809 | } |
| 3810 | |
| 3811 | /* Either the ACL failed the address, or it was deferred. */ |
| 3812 | |
| 3813 | else |
| 3814 | done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg); |
| 3815 | break; |
| 3816 | |
| 3817 | |
| 3818 | case VRFY_CMD: |
| 3819 | HAD(SCH_VRFY); |
| 3820 | rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg); |
| 3821 | if (rc != OK) |
| 3822 | done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg); |
| 3823 | else |
| 3824 | { |
| 3825 | uschar *address; |
| 3826 | uschar *s = NULL; |
| 3827 | |
| 3828 | /* rfc821_domains = TRUE; << no longer needed */ |
| 3829 | address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end, |
| 3830 | &recipient_domain, FALSE); |
| 3831 | /* rfc821_domains = FALSE; << no longer needed */ |
| 3832 | |
| 3833 | if (address == NULL) |
| 3834 | s = string_sprintf("501 %s", errmess); |
| 3835 | else |
| 3836 | { |
| 3837 | address_item *addr = deliver_make_addr(address, FALSE); |
| 3838 | switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1, |
| 3839 | -1, -1, NULL, NULL, NULL)) |
| 3840 | { |
| 3841 | case OK: |
| 3842 | s = string_sprintf("250 <%s> is deliverable", address); |
| 3843 | break; |
| 3844 | |
| 3845 | case DEFER: |
| 3846 | s = (addr->user_message != NULL)? |
| 3847 | string_sprintf("451 <%s> %s", address, addr->user_message) : |
| 3848 | string_sprintf("451 Cannot resolve <%s> at this time", address); |
| 3849 | break; |
| 3850 | |
| 3851 | case FAIL: |
| 3852 | s = (addr->user_message != NULL)? |
| 3853 | string_sprintf("550 <%s> %s", address, addr->user_message) : |
| 3854 | string_sprintf("550 <%s> is not deliverable", address); |
| 3855 | log_write(0, LOG_MAIN, "VRFY failed for %s %s", |
| 3856 | smtp_cmd_argument, host_and_ident(TRUE)); |
| 3857 | break; |
| 3858 | } |
| 3859 | } |
| 3860 | |
| 3861 | smtp_printf("%s\r\n", s); |
| 3862 | } |
| 3863 | break; |
| 3864 | |
| 3865 | |
| 3866 | case EXPN_CMD: |
| 3867 | HAD(SCH_EXPN); |
| 3868 | rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg); |
| 3869 | if (rc != OK) |
| 3870 | done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg); |
| 3871 | else |
| 3872 | { |
| 3873 | BOOL save_log_testing_mode = log_testing_mode; |
| 3874 | address_test_mode = log_testing_mode = TRUE; |
| 3875 | (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE), |
| 3876 | smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1, |
| 3877 | NULL, NULL, NULL); |
| 3878 | address_test_mode = FALSE; |
| 3879 | log_testing_mode = save_log_testing_mode; /* true for -bh */ |
| 3880 | } |
| 3881 | break; |
| 3882 | |
| 3883 | |
| 3884 | #ifdef SUPPORT_TLS |
| 3885 | |
| 3886 | case STARTTLS_CMD: |
| 3887 | HAD(SCH_STARTTLS); |
| 3888 | if (!tls_advertised) |
| 3889 | { |
| 3890 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 3891 | US"STARTTLS command used when not advertised"); |
| 3892 | break; |
| 3893 | } |
| 3894 | |
| 3895 | /* Apply an ACL check if one is defined */ |
| 3896 | |
| 3897 | if (acl_smtp_starttls != NULL) |
| 3898 | { |
| 3899 | rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg, |
| 3900 | &log_msg); |
| 3901 | if (rc != OK) |
| 3902 | { |
| 3903 | done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg); |
| 3904 | break; |
| 3905 | } |
| 3906 | } |
| 3907 | |
| 3908 | /* RFC 2487 is not clear on when this command may be sent, though it |
| 3909 | does state that all information previously obtained from the client |
| 3910 | must be discarded if a TLS session is started. It seems reasonble to |
| 3911 | do an implied RSET when STARTTLS is received. */ |
| 3912 | |
| 3913 | incomplete_transaction_log(US"STARTTLS"); |
| 3914 | smtp_reset(reset_point); |
| 3915 | toomany = FALSE; |
| 3916 | cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE; |
| 3917 | |
| 3918 | /* There's an attack where more data is read in past the STARTTLS command |
| 3919 | before TLS is negotiated, then assumed to be part of the secure session |
| 3920 | when used afterwards; we use segregated input buffers, so are not |
| 3921 | vulnerable, but we want to note when it happens and, for sheer paranoia, |
| 3922 | ensure that the buffer is "wiped". |
| 3923 | Pipelining sync checks will normally have protected us too, unless disabled |
| 3924 | by configuration. */ |
| 3925 | |
| 3926 | if (receive_smtp_buffered()) |
| 3927 | { |
| 3928 | DEBUG(D_any) |
| 3929 | debug_printf("Non-empty input buffer after STARTTLS; naive attack?"); |
| 3930 | if (tls_in.active < 0) |
| 3931 | smtp_inend = smtp_inptr = smtp_inbuffer; |
| 3932 | /* and if TLS is already active, tls_server_start() should fail */ |
| 3933 | } |
| 3934 | |
| 3935 | /* There is nothing we value in the input buffer and if TLS is succesfully |
| 3936 | negotiated, we won't use this buffer again; if TLS fails, we'll just read |
| 3937 | fresh content into it. The buffer contains arbitrary content from an |
| 3938 | untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n |
| 3939 | It seems safest to just wipe away the content rather than leave it as a |
| 3940 | target to jump to. */ |
| 3941 | |
| 3942 | memset(smtp_inbuffer, 0, in_buffer_size); |
| 3943 | |
| 3944 | /* Attempt to start up a TLS session, and if successful, discard all |
| 3945 | knowledge that was obtained previously. At least, that's what the RFC says, |
| 3946 | and that's what happens by default. However, in order to work round YAEB, |
| 3947 | there is an option to remember the esmtp state. Sigh. |
| 3948 | |
| 3949 | We must allow for an extra EHLO command and an extra AUTH command after |
| 3950 | STARTTLS that don't add to the nonmail command count. */ |
| 3951 | |
| 3952 | if ((rc = tls_server_start(tls_require_ciphers)) == OK) |
| 3953 | { |
| 3954 | if (!tls_remember_esmtp) |
| 3955 | helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE; |
| 3956 | cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE; |
| 3957 | cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE; |
| 3958 | if (sender_helo_name != NULL) |
| 3959 | { |
| 3960 | store_free(sender_helo_name); |
| 3961 | sender_helo_name = NULL; |
| 3962 | host_build_sender_fullhost(); /* Rebuild */ |
| 3963 | set_process_info("handling incoming TLS connection from %s", |
| 3964 | host_and_ident(FALSE)); |
| 3965 | } |
| 3966 | received_protocol = (esmtp? |
| 3967 | protocols[pextend + pcrpted + |
| 3968 | ((sender_host_authenticated != NULL)? pauthed : 0)] |
| 3969 | : |
| 3970 | protocols[pnormal + pcrpted]) |
| 3971 | + |
| 3972 | ((sender_host_address != NULL)? pnlocal : 0); |
| 3973 | |
| 3974 | sender_host_authenticated = NULL; |
| 3975 | authenticated_id = NULL; |
| 3976 | sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING; |
| 3977 | DEBUG(D_tls) debug_printf("TLS active\n"); |
| 3978 | break; /* Successful STARTTLS */ |
| 3979 | } |
| 3980 | |
| 3981 | /* Some local configuration problem was discovered before actually trying |
| 3982 | to do a TLS handshake; give a temporary error. */ |
| 3983 | |
| 3984 | else if (rc == DEFER) |
| 3985 | { |
| 3986 | smtp_printf("454 TLS currently unavailable\r\n"); |
| 3987 | break; |
| 3988 | } |
| 3989 | |
| 3990 | /* Hard failure. Reject everything except QUIT or closed connection. One |
| 3991 | cause for failure is a nested STARTTLS, in which case tls_in.active remains |
| 3992 | set, but we must still reject all incoming commands. */ |
| 3993 | |
| 3994 | DEBUG(D_tls) debug_printf("TLS failed to start\n"); |
| 3995 | while (done <= 0) |
| 3996 | { |
| 3997 | switch(smtp_read_command(FALSE)) |
| 3998 | { |
| 3999 | case EOF_CMD: |
| 4000 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF", |
| 4001 | smtp_get_connection_info()); |
| 4002 | smtp_notquit_exit(US"tls-failed", NULL, NULL); |
| 4003 | done = 2; |
| 4004 | break; |
| 4005 | |
| 4006 | /* It is perhaps arguable as to which exit ACL should be called here, |
| 4007 | but as it is probably a situation that almost never arises, it |
| 4008 | probably doesn't matter. We choose to call the real QUIT ACL, which in |
| 4009 | some sense is perhaps "right". */ |
| 4010 | |
| 4011 | case QUIT_CMD: |
| 4012 | user_msg = NULL; |
| 4013 | if (acl_smtp_quit != NULL) |
| 4014 | { |
| 4015 | rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, |
| 4016 | &log_msg); |
| 4017 | if (rc == ERROR) |
| 4018 | log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s", |
| 4019 | log_msg); |
| 4020 | } |
| 4021 | if (user_msg == NULL) |
| 4022 | smtp_printf("221 %s closing connection\r\n", smtp_active_hostname); |
| 4023 | else |
| 4024 | smtp_respond(US"221", 3, TRUE, user_msg); |
| 4025 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT", |
| 4026 | smtp_get_connection_info()); |
| 4027 | done = 2; |
| 4028 | break; |
| 4029 | |
| 4030 | default: |
| 4031 | smtp_printf("554 Security failure\r\n"); |
| 4032 | break; |
| 4033 | } |
| 4034 | } |
| 4035 | tls_close(TRUE, TRUE); |
| 4036 | break; |
| 4037 | #endif |
| 4038 | |
| 4039 | |
| 4040 | /* The ACL for QUIT is provided for gathering statistical information or |
| 4041 | similar; it does not affect the response code, but it can supply a custom |
| 4042 | message. */ |
| 4043 | |
| 4044 | case QUIT_CMD: |
| 4045 | HAD(SCH_QUIT); |
| 4046 | incomplete_transaction_log(US"QUIT"); |
| 4047 | if (acl_smtp_quit != NULL) |
| 4048 | { |
| 4049 | rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg); |
| 4050 | if (rc == ERROR) |
| 4051 | log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s", |
| 4052 | log_msg); |
| 4053 | } |
| 4054 | if (user_msg == NULL) |
| 4055 | smtp_printf("221 %s closing connection\r\n", smtp_active_hostname); |
| 4056 | else |
| 4057 | smtp_respond(US"221", 3, TRUE, user_msg); |
| 4058 | |
| 4059 | #ifdef SUPPORT_TLS |
| 4060 | tls_close(TRUE, TRUE); |
| 4061 | #endif |
| 4062 | |
| 4063 | done = 2; |
| 4064 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT", |
| 4065 | smtp_get_connection_info()); |
| 4066 | break; |
| 4067 | |
| 4068 | |
| 4069 | case RSET_CMD: |
| 4070 | HAD(SCH_RSET); |
| 4071 | incomplete_transaction_log(US"RSET"); |
| 4072 | smtp_reset(reset_point); |
| 4073 | toomany = FALSE; |
| 4074 | smtp_printf("250 Reset OK\r\n"); |
| 4075 | cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE; |
| 4076 | break; |
| 4077 | |
| 4078 | |
| 4079 | case NOOP_CMD: |
| 4080 | HAD(SCH_NOOP); |
| 4081 | smtp_printf("250 OK\r\n"); |
| 4082 | break; |
| 4083 | |
| 4084 | |
| 4085 | /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually |
| 4086 | used, a check will be done for permitted hosts. Show STARTTLS only if not |
| 4087 | already in a TLS session and if it would be advertised in the EHLO |
| 4088 | response. */ |
| 4089 | |
| 4090 | case HELP_CMD: |
| 4091 | HAD(SCH_HELP); |
| 4092 | smtp_printf("214-Commands supported:\r\n"); |
| 4093 | { |
| 4094 | uschar buffer[256]; |
| 4095 | buffer[0] = 0; |
| 4096 | Ustrcat(buffer, " AUTH"); |
| 4097 | #ifdef SUPPORT_TLS |
| 4098 | if (tls_in.active < 0 && |
| 4099 | verify_check_host(&tls_advertise_hosts) != FAIL) |
| 4100 | Ustrcat(buffer, " STARTTLS"); |
| 4101 | #endif |
| 4102 | Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA"); |
| 4103 | Ustrcat(buffer, " NOOP QUIT RSET HELP"); |
| 4104 | if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN"); |
| 4105 | if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN"); |
| 4106 | if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY"); |
| 4107 | smtp_printf("214%s\r\n", buffer); |
| 4108 | } |
| 4109 | break; |
| 4110 | |
| 4111 | |
| 4112 | case EOF_CMD: |
| 4113 | incomplete_transaction_log(US"connection lost"); |
| 4114 | smtp_notquit_exit(US"connection-lost", US"421", |
| 4115 | US"%s lost input connection", smtp_active_hostname); |
| 4116 | |
| 4117 | /* Don't log by default unless in the middle of a message, as some mailers |
| 4118 | just drop the call rather than sending QUIT, and it clutters up the logs. |
| 4119 | */ |
| 4120 | |
| 4121 | if (sender_address != NULL || recipients_count > 0) |
| 4122 | log_write(L_lost_incoming_connection, |
| 4123 | LOG_MAIN, |
| 4124 | "unexpected %s while reading SMTP command from %s%s", |
| 4125 | sender_host_unknown? "EOF" : "disconnection", |
| 4126 | host_and_ident(FALSE), smtp_read_error); |
| 4127 | |
| 4128 | else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s", |
| 4129 | smtp_get_connection_info(), smtp_read_error); |
| 4130 | |
| 4131 | done = 1; |
| 4132 | break; |
| 4133 | |
| 4134 | |
| 4135 | case ETRN_CMD: |
| 4136 | HAD(SCH_ETRN); |
| 4137 | if (sender_address != NULL) |
| 4138 | { |
| 4139 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 4140 | US"ETRN is not permitted inside a transaction"); |
| 4141 | break; |
| 4142 | } |
| 4143 | |
| 4144 | log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument, |
| 4145 | host_and_ident(FALSE)); |
| 4146 | |
| 4147 | rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg); |
| 4148 | if (rc != OK) |
| 4149 | { |
| 4150 | done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg); |
| 4151 | break; |
| 4152 | } |
| 4153 | |
| 4154 | /* Compute the serialization key for this command. */ |
| 4155 | |
| 4156 | etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data); |
| 4157 | |
| 4158 | /* If a command has been specified for running as a result of ETRN, we |
| 4159 | permit any argument to ETRN. If not, only the # standard form is permitted, |
| 4160 | since that is strictly the only kind of ETRN that can be implemented |
| 4161 | according to the RFC. */ |
| 4162 | |
| 4163 | if (smtp_etrn_command != NULL) |
| 4164 | { |
| 4165 | uschar *error; |
| 4166 | BOOL rc; |
| 4167 | etrn_command = smtp_etrn_command; |
| 4168 | deliver_domain = smtp_cmd_data; |
| 4169 | rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL, |
| 4170 | US"ETRN processing", &error); |
| 4171 | deliver_domain = NULL; |
| 4172 | if (!rc) |
| 4173 | { |
| 4174 | log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s", |
| 4175 | error); |
| 4176 | smtp_printf("458 Internal failure\r\n"); |
| 4177 | break; |
| 4178 | } |
| 4179 | } |
| 4180 | |
| 4181 | /* Else set up to call Exim with the -R option. */ |
| 4182 | |
| 4183 | else |
| 4184 | { |
| 4185 | if (*smtp_cmd_data++ != '#') |
| 4186 | { |
| 4187 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 4188 | US"argument must begin with #"); |
| 4189 | break; |
| 4190 | } |
| 4191 | etrn_command = US"exim -R"; |
| 4192 | argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R", |
| 4193 | smtp_cmd_data); |
| 4194 | } |
| 4195 | |
| 4196 | /* If we are host-testing, don't actually do anything. */ |
| 4197 | |
| 4198 | if (host_checking) |
| 4199 | { |
| 4200 | HDEBUG(D_any) |
| 4201 | { |
| 4202 | debug_printf("ETRN command is: %s\n", etrn_command); |
| 4203 | debug_printf("ETRN command execution skipped\n"); |
| 4204 | } |
| 4205 | if (user_msg == NULL) smtp_printf("250 OK\r\n"); |
| 4206 | else smtp_user_msg(US"250", user_msg); |
| 4207 | break; |
| 4208 | } |
| 4209 | |
| 4210 | |
| 4211 | /* If ETRN queue runs are to be serialized, check the database to |
| 4212 | ensure one isn't already running. */ |
| 4213 | |
| 4214 | if (smtp_etrn_serialize && !enq_start(etrn_serialize_key)) |
| 4215 | { |
| 4216 | smtp_printf("458 Already processing %s\r\n", smtp_cmd_data); |
| 4217 | break; |
| 4218 | } |
| 4219 | |
| 4220 | /* Fork a child process and run the command. We don't want to have to |
| 4221 | wait for the process at any point, so set SIGCHLD to SIG_IGN before |
| 4222 | forking. It should be set that way anyway for external incoming SMTP, |
| 4223 | but we save and restore to be tidy. If serialization is required, we |
| 4224 | actually run the command in yet another process, so we can wait for it |
| 4225 | to complete and then remove the serialization lock. */ |
| 4226 | |
| 4227 | oldsignal = signal(SIGCHLD, SIG_IGN); |
| 4228 | |
| 4229 | if ((pid = fork()) == 0) |
| 4230 | { |
| 4231 | smtp_input = FALSE; /* This process is not associated with the */ |
| 4232 | (void)fclose(smtp_in); /* SMTP call any more. */ |
| 4233 | (void)fclose(smtp_out); |
| 4234 | |
| 4235 | signal(SIGCHLD, SIG_DFL); /* Want to catch child */ |
| 4236 | |
| 4237 | /* If not serializing, do the exec right away. Otherwise, fork down |
| 4238 | into another process. */ |
| 4239 | |
| 4240 | if (!smtp_etrn_serialize || (pid = fork()) == 0) |
| 4241 | { |
| 4242 | DEBUG(D_exec) debug_print_argv(argv); |
| 4243 | exim_nullstd(); /* Ensure std{in,out,err} exist */ |
| 4244 | execv(CS argv[0], (char *const *)argv); |
| 4245 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s", |
| 4246 | etrn_command, strerror(errno)); |
| 4247 | _exit(EXIT_FAILURE); /* paranoia */ |
| 4248 | } |
| 4249 | |
| 4250 | /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That |
| 4251 | is, we are in the first subprocess, after forking again. All we can do |
| 4252 | for a failing fork is to log it. Otherwise, wait for the 2nd process to |
| 4253 | complete, before removing the serialization. */ |
| 4254 | |
| 4255 | if (pid < 0) |
| 4256 | log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN " |
| 4257 | "failed: %s", strerror(errno)); |
| 4258 | else |
| 4259 | { |
| 4260 | int status; |
| 4261 | DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n", |
| 4262 | (int)pid); |
| 4263 | (void)wait(&status); |
| 4264 | DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n", |
| 4265 | (int)pid); |
| 4266 | } |
| 4267 | |
| 4268 | enq_end(etrn_serialize_key); |
| 4269 | _exit(EXIT_SUCCESS); |
| 4270 | } |
| 4271 | |
| 4272 | /* Back in the top level SMTP process. Check that we started a subprocess |
| 4273 | and restore the signal state. */ |
| 4274 | |
| 4275 | if (pid < 0) |
| 4276 | { |
| 4277 | log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s", |
| 4278 | strerror(errno)); |
| 4279 | smtp_printf("458 Unable to fork process\r\n"); |
| 4280 | if (smtp_etrn_serialize) enq_end(etrn_serialize_key); |
| 4281 | } |
| 4282 | else |
| 4283 | { |
| 4284 | if (user_msg == NULL) smtp_printf("250 OK\r\n"); |
| 4285 | else smtp_user_msg(US"250", user_msg); |
| 4286 | } |
| 4287 | |
| 4288 | signal(SIGCHLD, oldsignal); |
| 4289 | break; |
| 4290 | |
| 4291 | |
| 4292 | case BADARG_CMD: |
| 4293 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 4294 | US"unexpected argument data"); |
| 4295 | break; |
| 4296 | |
| 4297 | |
| 4298 | /* This currently happens only for NULLs, but could be extended. */ |
| 4299 | |
| 4300 | case BADCHAR_CMD: |
| 4301 | done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */ |
| 4302 | US"NULL character(s) present (shown as '?')"); |
| 4303 | smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n"); |
| 4304 | break; |
| 4305 | |
| 4306 | |
| 4307 | case BADSYN_CMD: |
| 4308 | SYNC_FAILURE: |
| 4309 | if (smtp_inend >= smtp_inbuffer + in_buffer_size) |
| 4310 | smtp_inend = smtp_inbuffer + in_buffer_size - 1; |
| 4311 | c = smtp_inend - smtp_inptr; |
| 4312 | if (c > 150) c = 150; |
| 4313 | smtp_inptr[c] = 0; |
| 4314 | incomplete_transaction_log(US"sync failure"); |
| 4315 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error " |
| 4316 | "(next input sent too soon: pipelining was%s advertised): " |
| 4317 | "rejected \"%s\" %s next input=\"%s\"", |
| 4318 | pipelining_advertised? "" : " not", |
| 4319 | smtp_cmd_buffer, host_and_ident(TRUE), |
| 4320 | string_printing(smtp_inptr)); |
| 4321 | smtp_notquit_exit(US"synchronization-error", US"554", |
| 4322 | US"SMTP synchronization error"); |
| 4323 | done = 1; /* Pretend eof - drops connection */ |
| 4324 | break; |
| 4325 | |
| 4326 | |
| 4327 | case TOO_MANY_NONMAIL_CMD: |
| 4328 | s = smtp_cmd_buffer; |
| 4329 | while (*s != 0 && !isspace(*s)) s++; |
| 4330 | incomplete_transaction_log(US"too many non-mail commands"); |
| 4331 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " |
| 4332 | "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE), |
| 4333 | (int)(s - smtp_cmd_buffer), smtp_cmd_buffer); |
| 4334 | smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands"); |
| 4335 | done = 1; /* Pretend eof - drops connection */ |
| 4336 | break; |
| 4337 | |
| 4338 | |
| 4339 | default: |
| 4340 | if (unknown_command_count++ >= smtp_max_unknown_commands) |
| 4341 | { |
| 4342 | log_write(L_smtp_syntax_error, LOG_MAIN, |
| 4343 | "SMTP syntax error in \"%s\" %s %s", |
| 4344 | string_printing(smtp_cmd_buffer), host_and_ident(TRUE), |
| 4345 | US"unrecognized command"); |
| 4346 | incomplete_transaction_log(US"unrecognized command"); |
| 4347 | smtp_notquit_exit(US"bad-commands", US"500", |
| 4348 | US"Too many unrecognized commands"); |
| 4349 | done = 2; |
| 4350 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " |
| 4351 | "unrecognized commands (last was \"%s\")", host_and_ident(FALSE), |
| 4352 | smtp_cmd_buffer); |
| 4353 | } |
| 4354 | else |
| 4355 | done = synprot_error(L_smtp_syntax_error, 500, NULL, |
| 4356 | US"unrecognized command"); |
| 4357 | break; |
| 4358 | } |
| 4359 | |
| 4360 | /* This label is used by goto's inside loops that want to break out to |
| 4361 | the end of the command-processing loop. */ |
| 4362 | |
| 4363 | COMMAND_LOOP: |
| 4364 | last_was_rej_mail = was_rej_mail; /* Remember some last commands for */ |
| 4365 | last_was_rcpt = was_rcpt; /* protocol error handling */ |
| 4366 | continue; |
| 4367 | } |
| 4368 | |
| 4369 | return done - 2; /* Convert yield values */ |
| 4370 | } |
| 4371 | |
| 4372 | /* End of smtp_in.c */ |