| 1 | /* $Cambridge: exim/src/src/smtp_in.c,v 1.1 2004/10/07 10:39:01 ph10 Exp $ */ |
| 2 | |
| 3 | /************************************************* |
| 4 | * Exim - an Internet mail transport agent * |
| 5 | *************************************************/ |
| 6 | |
| 7 | /* Copyright (c) University of Cambridge 1995 - 2004 */ |
| 8 | /* See the file NOTICE for conditions of use and distribution. */ |
| 9 | |
| 10 | /* Functions for handling an incoming SMTP call. */ |
| 11 | |
| 12 | |
| 13 | #include "exim.h" |
| 14 | |
| 15 | |
| 16 | /* Initialize for TCP wrappers if so configured. It appears that the macro |
| 17 | HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before |
| 18 | including that header, and restore its value afterwards. */ |
| 19 | |
| 20 | #ifdef USE_TCP_WRAPPERS |
| 21 | |
| 22 | #if HAVE_IPV6 |
| 23 | #define EXIM_HAVE_IPV6 |
| 24 | #endif |
| 25 | #undef HAVE_IPV6 |
| 26 | #include <tcpd.h> |
| 27 | #undef HAVE_IPV6 |
| 28 | #ifdef EXIM_HAVE_IPV6 |
| 29 | #define HAVE_IPV6 TRUE |
| 30 | #endif |
| 31 | |
| 32 | int allow_severity = LOG_INFO; |
| 33 | int deny_severity = LOG_NOTICE; |
| 34 | #endif |
| 35 | |
| 36 | |
| 37 | /* Size of buffer for reading SMTP commands */ |
| 38 | |
| 39 | #define cmd_buffer_size 512 /* Ref. RFC 821 */ |
| 40 | |
| 41 | /* Size of buffer for reading SMTP incoming packets */ |
| 42 | |
| 43 | #define in_buffer_size 8192 |
| 44 | |
| 45 | /* Structure for SMTP command list */ |
| 46 | |
| 47 | typedef struct { |
| 48 | char *name; |
| 49 | int len; |
| 50 | short int cmd; |
| 51 | short int has_arg; |
| 52 | short int is_mail_cmd; |
| 53 | } smtp_cmd_list; |
| 54 | |
| 55 | /* Codes for identifying commands. We order them so that those that come first |
| 56 | are those for which synchronization is always required. Checking this can help |
| 57 | block some spam. */ |
| 58 | |
| 59 | enum { |
| 60 | /* These commands are required to be synchronized, i.e. to be the last in a |
| 61 | block of commands when pipelining. */ |
| 62 | |
| 63 | HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */ |
| 64 | VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */ |
| 65 | ETRN_CMD, /* This by analogy with TURN from the RFC */ |
| 66 | STARTTLS_CMD, /* Required by the STARTTLS RFC */ |
| 67 | |
| 68 | /* This is a dummy to identify the non-sync commands when pipelining */ |
| 69 | |
| 70 | NON_SYNC_CMD_PIPELINING, |
| 71 | |
| 72 | /* These commands need not be synchronized when pipelining */ |
| 73 | |
| 74 | MAIL_CMD, RCPT_CMD, RSET_CMD, |
| 75 | |
| 76 | /* This is a dummy to identify the non-sync commands when not pipelining */ |
| 77 | |
| 78 | NON_SYNC_CMD_NON_PIPELINING, |
| 79 | |
| 80 | /* I have been unable to find a statement about the use of pipelining |
| 81 | with AUTH, so to be on the safe side it is here, though I kind of feel |
| 82 | it should be up there with the synchronized commands. */ |
| 83 | |
| 84 | AUTH_CMD, |
| 85 | |
| 86 | /* I'm not sure about these, but I don't think they matter. */ |
| 87 | |
| 88 | QUIT_CMD, HELP_CMD, |
| 89 | |
| 90 | /* These are specials that don't correspond to actual commands */ |
| 91 | |
| 92 | EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD, |
| 93 | TOO_MANY_NONMAIL_CMD }; |
| 94 | |
| 95 | |
| 96 | |
| 97 | /************************************************* |
| 98 | * Local static variables * |
| 99 | *************************************************/ |
| 100 | |
| 101 | static auth_instance *authenticated_by; |
| 102 | static BOOL auth_advertised; |
| 103 | #ifdef SUPPORT_TLS |
| 104 | static BOOL tls_advertised; |
| 105 | #endif |
| 106 | static BOOL esmtp; |
| 107 | static BOOL helo_required = FALSE; |
| 108 | static BOOL helo_verify = FALSE; |
| 109 | static BOOL helo_seen; |
| 110 | static BOOL helo_accept_junk; |
| 111 | static BOOL count_nonmail; |
| 112 | static BOOL pipelining_advertised; |
| 113 | static int nonmail_command_count; |
| 114 | static int synprot_error_count; |
| 115 | static int unknown_command_count; |
| 116 | static int sync_cmd_limit; |
| 117 | static int smtp_write_error = 0; |
| 118 | |
| 119 | static uschar *smtp_data; |
| 120 | |
| 121 | static uschar *cmd_buffer; |
| 122 | |
| 123 | /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their |
| 124 | final fields of all except AUTH are forced TRUE at the start of a new message |
| 125 | setup, to allow one of each between messages that is not counted as a nonmail |
| 126 | command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to |
| 127 | allow a new EHLO after starting up TLS. |
| 128 | |
| 129 | AUTH is "falsely" labelled as a mail command initially, so that it doesn't get |
| 130 | counted. However, the flag is changed when AUTH is received, so that multiple |
| 131 | failing AUTHs will eventually hit the limit. After a successful AUTH, another |
| 132 | AUTH is already forbidden. After a TLS session is started, AUTH's flag is again |
| 133 | forced TRUE, to allow for the re-authentication that can happen at that point. |
| 134 | |
| 135 | QUIT is also "falsely" labelled as a mail command so that it doesn't up the |
| 136 | count of non-mail commands and possibly provoke an error. */ |
| 137 | |
| 138 | static smtp_cmd_list cmd_list[] = { |
| 139 | { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */ |
| 140 | { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE }, |
| 141 | { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE }, |
| 142 | { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE }, |
| 143 | #ifdef SUPPORT_TLS |
| 144 | { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE }, |
| 145 | #endif |
| 146 | |
| 147 | /* If you change anything above here, also fix the definitions below. */ |
| 148 | |
| 149 | { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE }, |
| 150 | { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE }, |
| 151 | { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE }, |
| 152 | { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE }, |
| 153 | { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE }, |
| 154 | { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE }, |
| 155 | { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE }, |
| 156 | { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE }, |
| 157 | { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE } |
| 158 | }; |
| 159 | |
| 160 | static smtp_cmd_list *cmd_list_end = |
| 161 | cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list); |
| 162 | |
| 163 | #define CMD_LIST_RSET 0 |
| 164 | #define CMD_LIST_HELO 1 |
| 165 | #define CMD_LIST_EHLO 2 |
| 166 | #define CMD_LIST_AUTH 3 |
| 167 | #define CMD_LIST_STARTTLS 4 |
| 168 | |
| 169 | static uschar *protocols[] = { |
| 170 | US"local-smtp", |
| 171 | US"local-esmtp", |
| 172 | US"local-esmtpa", |
| 173 | US"local-esmtps", |
| 174 | US"local-esmtpsa" |
| 175 | }; |
| 176 | |
| 177 | #define pnormal 0 |
| 178 | #define pextend 1 |
| 179 | #define pauthed 1 /* added to pextend */ |
| 180 | #define pcrpted 2 /* added to pextend */ |
| 181 | #define pnlocal 6 /* offset to remove "local" */ |
| 182 | |
| 183 | /* When reading SMTP from a remote host, we have to use our own versions of the |
| 184 | C input-reading functions, in order to be able to flush the SMTP output only |
| 185 | when about to read more data from the socket. This is the only way to get |
| 186 | optimal performance when the client is using pipelining. Flushing for every |
| 187 | command causes a separate packet and reply packet each time; saving all the |
| 188 | responses up (when pipelining) combines them into one packet and one response. |
| 189 | |
| 190 | For simplicity, these functions are used for *all* SMTP input, not only when |
| 191 | receiving over a socket. However, after setting up a secure socket (SSL), input |
| 192 | is read via the OpenSSL library, and another set of functions is used instead |
| 193 | (see tls.c). |
| 194 | |
| 195 | These functions are set in the receive_getc etc. variables and called with the |
| 196 | same interface as the C functions. However, since there can only ever be |
| 197 | one incoming SMTP call, we just use a single buffer and flags. There is no need |
| 198 | to implement a complicated private FILE-like structure.*/ |
| 199 | |
| 200 | static uschar *smtp_inbuffer; |
| 201 | static uschar *smtp_inptr; |
| 202 | static uschar *smtp_inend; |
| 203 | static int smtp_had_eof; |
| 204 | static int smtp_had_error; |
| 205 | |
| 206 | |
| 207 | /************************************************* |
| 208 | * SMTP version of getc() * |
| 209 | *************************************************/ |
| 210 | |
| 211 | /* This gets the next byte from the SMTP input buffer. If the buffer is empty, |
| 212 | it flushes the output, and refills the buffer, with a timeout. The signal |
| 213 | handler is set appropriately by the calling function. This function is not used |
| 214 | after a connection has negotated itself into an TLS/SSL state. |
| 215 | |
| 216 | Arguments: none |
| 217 | Returns: the next character or EOF |
| 218 | */ |
| 219 | |
| 220 | int |
| 221 | smtp_getc(void) |
| 222 | { |
| 223 | if (smtp_inptr >= smtp_inend) |
| 224 | { |
| 225 | int rc, save_errno; |
| 226 | fflush(smtp_out); |
| 227 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); |
| 228 | rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size); |
| 229 | save_errno = errno; |
| 230 | alarm(0); |
| 231 | if (rc <= 0) |
| 232 | { |
| 233 | /* Must put the error text in fixed store, because this might be during |
| 234 | header reading, where it releases unused store above the header. */ |
| 235 | if (rc < 0) |
| 236 | { |
| 237 | smtp_had_error = save_errno; |
| 238 | smtp_read_error = string_copy_malloc( |
| 239 | string_sprintf(" (error: %s)", strerror(save_errno))); |
| 240 | } |
| 241 | else smtp_had_eof = 1; |
| 242 | return EOF; |
| 243 | } |
| 244 | smtp_inend = smtp_inbuffer + rc; |
| 245 | smtp_inptr = smtp_inbuffer; |
| 246 | } |
| 247 | return *smtp_inptr++; |
| 248 | } |
| 249 | |
| 250 | |
| 251 | |
| 252 | /************************************************* |
| 253 | * SMTP version of ungetc() * |
| 254 | *************************************************/ |
| 255 | |
| 256 | /* Puts a character back in the input buffer. Only ever |
| 257 | called once. |
| 258 | |
| 259 | Arguments: |
| 260 | ch the character |
| 261 | |
| 262 | Returns: the character |
| 263 | */ |
| 264 | |
| 265 | int |
| 266 | smtp_ungetc(int ch) |
| 267 | { |
| 268 | *(--smtp_inptr) = ch; |
| 269 | return ch; |
| 270 | } |
| 271 | |
| 272 | |
| 273 | |
| 274 | |
| 275 | /************************************************* |
| 276 | * SMTP version of feof() * |
| 277 | *************************************************/ |
| 278 | |
| 279 | /* Tests for a previous EOF |
| 280 | |
| 281 | Arguments: none |
| 282 | Returns: non-zero if the eof flag is set |
| 283 | */ |
| 284 | |
| 285 | int |
| 286 | smtp_feof(void) |
| 287 | { |
| 288 | return smtp_had_eof; |
| 289 | } |
| 290 | |
| 291 | |
| 292 | |
| 293 | |
| 294 | /************************************************* |
| 295 | * SMTP version of ferror() * |
| 296 | *************************************************/ |
| 297 | |
| 298 | /* Tests for a previous read error, and returns with errno |
| 299 | restored to what it was when the error was detected. |
| 300 | |
| 301 | Arguments: none |
| 302 | Returns: non-zero if the error flag is set |
| 303 | */ |
| 304 | |
| 305 | int |
| 306 | smtp_ferror(void) |
| 307 | { |
| 308 | errno = smtp_had_error; |
| 309 | return smtp_had_error; |
| 310 | } |
| 311 | |
| 312 | |
| 313 | |
| 314 | |
| 315 | /************************************************* |
| 316 | * Write formatted string to SMTP channel * |
| 317 | *************************************************/ |
| 318 | |
| 319 | /* This is a separate function so that we don't have to repeat everything for |
| 320 | TLS support or debugging. It is global so that the daemon and the |
| 321 | authentication functions can use it. It does not return any error indication, |
| 322 | because major problems such as dropped connections won't show up till an output |
| 323 | flush for non-TLS connections. The smtp_fflush() function is available for |
| 324 | checking that: for convenience, TLS output errors are remembered here so that |
| 325 | they are also picked up later by smtp_fflush(). |
| 326 | |
| 327 | Arguments: |
| 328 | format format string |
| 329 | ... optional arguments |
| 330 | |
| 331 | Returns: nothing |
| 332 | */ |
| 333 | |
| 334 | void |
| 335 | smtp_printf(char *format, ...) |
| 336 | { |
| 337 | va_list ap; |
| 338 | |
| 339 | DEBUG(D_receive) |
| 340 | { |
| 341 | va_start(ap, format); |
| 342 | (void) string_vformat(big_buffer, big_buffer_size, format, ap); |
| 343 | debug_printf("SMTP>> %s", big_buffer); |
| 344 | } |
| 345 | |
| 346 | va_start(ap, format); |
| 347 | |
| 348 | /* If in a TLS session we have to format the string, and then write it using a |
| 349 | TLS function. */ |
| 350 | |
| 351 | #ifdef SUPPORT_TLS |
| 352 | if (tls_active >= 0) |
| 353 | { |
| 354 | if (!string_vformat(big_buffer, big_buffer_size, format, ap)) |
| 355 | { |
| 356 | log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf"); |
| 357 | smtp_closedown(US"Unexpected error"); |
| 358 | exim_exit(EXIT_FAILURE); |
| 359 | } |
| 360 | if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1; |
| 361 | } |
| 362 | else |
| 363 | #endif |
| 364 | |
| 365 | /* Otherwise, just use the standard library function. */ |
| 366 | |
| 367 | if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1; |
| 368 | va_end(ap); |
| 369 | } |
| 370 | |
| 371 | |
| 372 | |
| 373 | /************************************************* |
| 374 | * Flush SMTP out and check for error * |
| 375 | *************************************************/ |
| 376 | |
| 377 | /* This function isn't currently used within Exim (it detects errors when it |
| 378 | tries to read the next SMTP input), but is available for use in local_scan(). |
| 379 | For non-TLS connections, it flushes the output and checks for errors. For |
| 380 | TLS-connections, it checks for a previously-detected TLS write error. |
| 381 | |
| 382 | Arguments: none |
| 383 | Returns: 0 for no error; -1 after an error |
| 384 | */ |
| 385 | |
| 386 | int |
| 387 | smtp_fflush(void) |
| 388 | { |
| 389 | if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1; |
| 390 | return smtp_write_error; |
| 391 | } |
| 392 | |
| 393 | |
| 394 | |
| 395 | /************************************************* |
| 396 | * SMTP command read timeout * |
| 397 | *************************************************/ |
| 398 | |
| 399 | /* Signal handler for timing out incoming SMTP commands. This attempts to |
| 400 | finish off tidily. |
| 401 | |
| 402 | Argument: signal number (SIGALRM) |
| 403 | Returns: nothing |
| 404 | */ |
| 405 | |
| 406 | static void |
| 407 | command_timeout_handler(int sig) |
| 408 | { |
| 409 | sig = sig; /* Keep picky compilers happy */ |
| 410 | log_write(L_lost_incoming_connection, |
| 411 | LOG_MAIN, "SMTP command timeout on%s connection from %s", |
| 412 | (tls_active >= 0)? " TLS" : "", |
| 413 | host_and_ident(FALSE)); |
| 414 | if (smtp_batched_input) |
| 415 | moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */ |
| 416 | smtp_printf("421 %s: SMTP command timeout - closing connection\r\n", |
| 417 | smtp_active_hostname); |
| 418 | mac_smtp_fflush(); |
| 419 | exim_exit(EXIT_FAILURE); |
| 420 | } |
| 421 | |
| 422 | |
| 423 | |
| 424 | /************************************************* |
| 425 | * SIGTERM received * |
| 426 | *************************************************/ |
| 427 | |
| 428 | /* Signal handler for handling SIGTERM. Again, try to finish tidily. |
| 429 | |
| 430 | Argument: signal number (SIGTERM) |
| 431 | Returns: nothing |
| 432 | */ |
| 433 | |
| 434 | static void |
| 435 | command_sigterm_handler(int sig) |
| 436 | { |
| 437 | sig = sig; /* Keep picky compilers happy */ |
| 438 | log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info()); |
| 439 | if (smtp_batched_input) |
| 440 | moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */ |
| 441 | smtp_printf("421 %s: Service not available - closing connection\r\n", |
| 442 | smtp_active_hostname); |
| 443 | exim_exit(EXIT_FAILURE); |
| 444 | } |
| 445 | |
| 446 | |
| 447 | |
| 448 | /************************************************* |
| 449 | * Read one command line * |
| 450 | *************************************************/ |
| 451 | |
| 452 | /* Strictly, SMTP commands coming over the net are supposed to end with CRLF. |
| 453 | There are sites that don't do this, and in any case internal SMTP probably |
| 454 | should check only for LF. Consequently, we check here for LF only. The line |
| 455 | ends up with [CR]LF removed from its end. If we get an overlong line, treat as |
| 456 | an unknown command. The command is read into the static cmd_buffer. |
| 457 | |
| 458 | The character reading routine sets up a timeout for each block actually read |
| 459 | from the input (which may contain more than one command). We set up a special |
| 460 | signal handler that closes down the session on a timeout. Control does not |
| 461 | return when it runs. |
| 462 | |
| 463 | Arguments: |
| 464 | check_sync if TRUE, check synchronization rules if global option is TRUE |
| 465 | |
| 466 | Returns: a code identifying the command (enumerated above) |
| 467 | */ |
| 468 | |
| 469 | static int |
| 470 | smtp_read_command(BOOL check_sync) |
| 471 | { |
| 472 | int c; |
| 473 | int ptr = 0; |
| 474 | smtp_cmd_list *p; |
| 475 | BOOL hadnull = FALSE; |
| 476 | |
| 477 | os_non_restarting_signal(SIGALRM, command_timeout_handler); |
| 478 | |
| 479 | while ((c = (receive_getc)()) != '\n' && c != EOF) |
| 480 | { |
| 481 | if (ptr >= cmd_buffer_size) |
| 482 | { |
| 483 | os_non_restarting_signal(SIGALRM, sigalrm_handler); |
| 484 | return OTHER_CMD; |
| 485 | } |
| 486 | if (c == 0) |
| 487 | { |
| 488 | hadnull = TRUE; |
| 489 | c = '?'; |
| 490 | } |
| 491 | cmd_buffer[ptr++] = c; |
| 492 | } |
| 493 | |
| 494 | receive_linecount++; /* For BSMTP errors */ |
| 495 | os_non_restarting_signal(SIGALRM, sigalrm_handler); |
| 496 | |
| 497 | /* If hit end of file, return pseudo EOF command. Whether we have a |
| 498 | part-line already read doesn't matter, since this is an error state. */ |
| 499 | |
| 500 | if (c == EOF) return EOF_CMD; |
| 501 | |
| 502 | /* Remove any CR and white space at the end of the line, and terminate the |
| 503 | string. */ |
| 504 | |
| 505 | while (ptr > 0 && isspace(cmd_buffer[ptr-1])) ptr--; |
| 506 | cmd_buffer[ptr] = 0; |
| 507 | |
| 508 | DEBUG(D_receive) debug_printf("SMTP<< %s\n", cmd_buffer); |
| 509 | |
| 510 | /* NULLs are not allowed in SMTP commands */ |
| 511 | |
| 512 | if (hadnull) return BADCHAR_CMD; |
| 513 | |
| 514 | /* Scan command list and return identity, having set the data pointer |
| 515 | to the start of the actual data characters. Check for SMTP synchronization |
| 516 | if required. */ |
| 517 | |
| 518 | for (p = cmd_list; p < cmd_list_end; p++) |
| 519 | { |
| 520 | if (strncmpic(cmd_buffer, US p->name, p->len) == 0) |
| 521 | { |
| 522 | if (smtp_inptr < smtp_inend && /* Outstanding input */ |
| 523 | p->cmd < sync_cmd_limit && /* Command should sync */ |
| 524 | check_sync && /* Local flag set */ |
| 525 | smtp_enforce_sync && /* Global flag set */ |
| 526 | sender_host_address != NULL && /* Not local input */ |
| 527 | !sender_host_notsocket) /* Really is a socket */ |
| 528 | return BADSYN_CMD; |
| 529 | |
| 530 | /* Point after the command, but don't skip over leading spaces till after |
| 531 | the following test, so that if it fails, the command name can easily be |
| 532 | logged. */ |
| 533 | |
| 534 | smtp_data = cmd_buffer + p->len; |
| 535 | |
| 536 | /* Count non-mail commands from those hosts that are controlled in this |
| 537 | way. The default is all hosts. We don't waste effort checking the list |
| 538 | until we get a non-mail command, but then cache the result to save checking |
| 539 | again. If there's a DEFER while checking the host, assume it's in the list. |
| 540 | |
| 541 | Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the |
| 542 | start of each incoming message by fiddling with the value in the table. */ |
| 543 | |
| 544 | if (!p->is_mail_cmd) |
| 545 | { |
| 546 | if (count_nonmail == TRUE_UNSET) count_nonmail = |
| 547 | verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL; |
| 548 | if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail) |
| 549 | return TOO_MANY_NONMAIL_CMD; |
| 550 | } |
| 551 | |
| 552 | /* Get the data pointer over leading spaces and return; if there is no data |
| 553 | for a command that expects it, we give the error centrally here. */ |
| 554 | |
| 555 | while (isspace(*smtp_data)) smtp_data++; |
| 556 | return (p->has_arg || *smtp_data == 0)? p->cmd : BADARG_CMD; |
| 557 | } |
| 558 | } |
| 559 | |
| 560 | /* Enforce synchronization for unknown commands */ |
| 561 | |
| 562 | if (smtp_inptr < smtp_inend && /* Outstanding input */ |
| 563 | check_sync && /* Local flag set */ |
| 564 | smtp_enforce_sync && /* Global flag set */ |
| 565 | sender_host_address != NULL && /* Not local input */ |
| 566 | !sender_host_notsocket) /* Really is a socket */ |
| 567 | return BADSYN_CMD; |
| 568 | |
| 569 | return OTHER_CMD; |
| 570 | } |
| 571 | |
| 572 | |
| 573 | |
| 574 | /************************************************* |
| 575 | * Forced closedown of call * |
| 576 | *************************************************/ |
| 577 | |
| 578 | /* This function is called from log.c when Exim is dying because of a serious |
| 579 | disaster, and also from some other places. If an incoming non-batched SMTP |
| 580 | channel is open, it swallows the rest of the incoming message if in the DATA |
| 581 | phase, sends the reply string, and gives an error to all subsequent commands |
| 582 | except QUIT. The existence of an SMTP call is detected by the non-NULLness of |
| 583 | smtp_in. |
| 584 | |
| 585 | Argument: SMTP reply string to send, excluding the code |
| 586 | Returns: nothing |
| 587 | */ |
| 588 | |
| 589 | void |
| 590 | smtp_closedown(uschar *message) |
| 591 | { |
| 592 | if (smtp_in == NULL || smtp_batched_input) return; |
| 593 | receive_swallow_smtp(); |
| 594 | smtp_printf("421 %s\r\n", message); |
| 595 | |
| 596 | for (;;) |
| 597 | { |
| 598 | switch(smtp_read_command(FALSE)) |
| 599 | { |
| 600 | case EOF_CMD: |
| 601 | return; |
| 602 | |
| 603 | case QUIT_CMD: |
| 604 | smtp_printf("221 %s closing connection\r\n", smtp_active_hostname); |
| 605 | mac_smtp_fflush(); |
| 606 | return; |
| 607 | |
| 608 | case RSET_CMD: |
| 609 | smtp_printf("250 Reset OK\r\n"); |
| 610 | break; |
| 611 | |
| 612 | default: |
| 613 | smtp_printf("421 %s\r\n", message); |
| 614 | break; |
| 615 | } |
| 616 | } |
| 617 | } |
| 618 | |
| 619 | |
| 620 | |
| 621 | |
| 622 | /************************************************* |
| 623 | * Set up connection info for logging * |
| 624 | *************************************************/ |
| 625 | |
| 626 | /* This function is called when logging information about an SMTP connection. |
| 627 | It sets up appropriate source information, depending on the type of connection. |
| 628 | |
| 629 | Argument: none |
| 630 | Returns: a string describing the connection |
| 631 | */ |
| 632 | |
| 633 | uschar * |
| 634 | smtp_get_connection_info(void) |
| 635 | { |
| 636 | if (host_checking) |
| 637 | return string_sprintf("SMTP connection from %s", sender_fullhost); |
| 638 | |
| 639 | if (sender_host_unknown || sender_host_notsocket) |
| 640 | return string_sprintf("SMTP connection from %s", sender_ident); |
| 641 | |
| 642 | if (is_inetd) |
| 643 | return string_sprintf("SMTP connection from %s (via inetd)", sender_fullhost); |
| 644 | |
| 645 | if ((log_extra_selector & LX_incoming_interface) != 0 && |
| 646 | interface_address != NULL) |
| 647 | return string_sprintf("SMTP connection from %s I=[%s]:%d", sender_fullhost, |
| 648 | interface_address, interface_port); |
| 649 | |
| 650 | return string_sprintf("SMTP connection from %s", sender_fullhost); |
| 651 | } |
| 652 | |
| 653 | |
| 654 | |
| 655 | /************************************************* |
| 656 | * Check HELO line and set sender_helo_name * |
| 657 | *************************************************/ |
| 658 | |
| 659 | /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be |
| 660 | the domain name of the sending host, or an ip literal in square brackets. The |
| 661 | arrgument is placed in sender_helo_name, which is in malloc store, because it |
| 662 | must persist over multiple incoming messages. If helo_accept_junk is set, this |
| 663 | host is permitted to send any old junk (needed for some broken hosts). |
| 664 | Otherwise, helo_allow_chars can be used for rogue characters in general |
| 665 | (typically people want to let in underscores). |
| 666 | |
| 667 | Argument: |
| 668 | s the data portion of the line (already past any white space) |
| 669 | |
| 670 | Returns: TRUE or FALSE |
| 671 | */ |
| 672 | |
| 673 | static BOOL |
| 674 | check_helo(uschar *s) |
| 675 | { |
| 676 | uschar *start = s; |
| 677 | uschar *end = s + Ustrlen(s); |
| 678 | BOOL yield = helo_accept_junk; |
| 679 | |
| 680 | /* Discard any previous helo name */ |
| 681 | |
| 682 | if (sender_helo_name != NULL) |
| 683 | { |
| 684 | store_free(sender_helo_name); |
| 685 | sender_helo_name = NULL; |
| 686 | } |
| 687 | |
| 688 | /* Skip tests if junk is permitted. */ |
| 689 | |
| 690 | if (!yield) |
| 691 | { |
| 692 | /* Allow the new standard form for IPv6 address literals, namely, |
| 693 | [IPv6:....], and because someone is bound to use it, allow an equivalent |
| 694 | IPv4 form. Allow plain addresses as well. */ |
| 695 | |
| 696 | if (*s == '[') |
| 697 | { |
| 698 | if (end[-1] == ']') |
| 699 | { |
| 700 | end[-1] = 0; |
| 701 | if (strncmpic(s, US"[IPv6:", 6) == 0) |
| 702 | yield = (string_is_ip_address(s+6, NULL) == 6); |
| 703 | else if (strncmpic(s, US"[IPv4:", 6) == 0) |
| 704 | yield = (string_is_ip_address(s+6, NULL) == 4); |
| 705 | else |
| 706 | yield = (string_is_ip_address(s+1, NULL) != 0); |
| 707 | end[-1] = ']'; |
| 708 | } |
| 709 | } |
| 710 | |
| 711 | /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars |
| 712 | that have been configured (usually underscore - sigh). */ |
| 713 | |
| 714 | else if (*s != 0) |
| 715 | { |
| 716 | yield = TRUE; |
| 717 | while (*s != 0) |
| 718 | { |
| 719 | if (!isalnum(*s) && *s != '.' && *s != '-' && |
| 720 | Ustrchr(helo_allow_chars, *s) == NULL) |
| 721 | { |
| 722 | yield = FALSE; |
| 723 | break; |
| 724 | } |
| 725 | s++; |
| 726 | } |
| 727 | } |
| 728 | } |
| 729 | |
| 730 | /* Save argument if OK */ |
| 731 | |
| 732 | if (yield) sender_helo_name = string_copy_malloc(start); |
| 733 | return yield; |
| 734 | } |
| 735 | |
| 736 | |
| 737 | |
| 738 | |
| 739 | |
| 740 | /************************************************* |
| 741 | * Extract SMTP command option * |
| 742 | *************************************************/ |
| 743 | |
| 744 | /* This function picks the next option setting off the end of smtp_data. It |
| 745 | is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP |
| 746 | things that can appear there. |
| 747 | |
| 748 | Arguments: |
| 749 | name point this at the name |
| 750 | value point this at the data string |
| 751 | |
| 752 | Returns: TRUE if found an option |
| 753 | */ |
| 754 | |
| 755 | static BOOL |
| 756 | extract_option(uschar **name, uschar **value) |
| 757 | { |
| 758 | uschar *n; |
| 759 | uschar *v = smtp_data + Ustrlen(smtp_data) -1; |
| 760 | while (isspace(*v)) v--; |
| 761 | v[1] = 0; |
| 762 | |
| 763 | while (v > smtp_data && *v != '=' && !isspace(*v)) v--; |
| 764 | if (*v != '=') return FALSE; |
| 765 | |
| 766 | n = v; |
| 767 | while(isalpha(n[-1])) n--; |
| 768 | |
| 769 | if (n[-1] != ' ') return FALSE; |
| 770 | |
| 771 | n[-1] = 0; |
| 772 | *name = n; |
| 773 | *v++ = 0; |
| 774 | *value = v; |
| 775 | return TRUE; |
| 776 | } |
| 777 | |
| 778 | |
| 779 | |
| 780 | |
| 781 | |
| 782 | |
| 783 | |
| 784 | /************************************************* |
| 785 | * Reset for new message * |
| 786 | *************************************************/ |
| 787 | |
| 788 | /* This function is called whenever the SMTP session is reset from |
| 789 | within either of the setup functions. |
| 790 | |
| 791 | Argument: the stacking pool storage reset point |
| 792 | Returns: nothing |
| 793 | */ |
| 794 | |
| 795 | static void |
| 796 | smtp_reset(void *reset_point) |
| 797 | { |
| 798 | int i; |
| 799 | store_reset(reset_point); |
| 800 | recipients_list = NULL; |
| 801 | rcpt_count = rcpt_defer_count = rcpt_fail_count = |
| 802 | raw_recipients_count = recipients_count = recipients_list_max = 0; |
| 803 | message_size = -1; |
| 804 | acl_warn_headers = NULL; |
| 805 | queue_only_policy = FALSE; |
| 806 | deliver_freeze = FALSE; /* Can be set by ACL */ |
| 807 | submission_mode = FALSE; /* Can be set by ACL */ |
| 808 | sender_address = NULL; |
| 809 | raw_sender = NULL; /* After SMTP rewrite, before qualifying */ |
| 810 | sender_address_unrewritten = NULL; /* Set only after verify rewrite */ |
| 811 | sender_verified_list = NULL; /* No senders verified */ |
| 812 | memset(sender_address_cache, 0, sizeof(sender_address_cache)); |
| 813 | memset(sender_domain_cache, 0, sizeof(sender_domain_cache)); |
| 814 | authenticated_sender = NULL; |
| 815 | body_linecount = body_zerocount = 0; |
| 816 | |
| 817 | for (i = 0; i < ACL_M_MAX; i++) acl_var[ACL_C_MAX + i] = NULL; |
| 818 | |
| 819 | /* The message body variables use malloc store. They may be set if this is |
| 820 | not the first message in an SMTP session and the previous message caused them |
| 821 | to be referenced in an ACL. */ |
| 822 | |
| 823 | if (message_body != NULL) |
| 824 | { |
| 825 | store_free(message_body); |
| 826 | message_body = NULL; |
| 827 | } |
| 828 | |
| 829 | if (message_body_end != NULL) |
| 830 | { |
| 831 | store_free(message_body_end); |
| 832 | message_body_end = NULL; |
| 833 | } |
| 834 | |
| 835 | /* Warning log messages are also saved in malloc store. They are saved to avoid |
| 836 | repetition in the same message, but it seems right to repeat them for different |
| 837 | messagess. */ |
| 838 | |
| 839 | while (acl_warn_logged != NULL) |
| 840 | { |
| 841 | string_item *this = acl_warn_logged; |
| 842 | acl_warn_logged = acl_warn_logged->next; |
| 843 | store_free(this); |
| 844 | } |
| 845 | } |
| 846 | |
| 847 | |
| 848 | |
| 849 | |
| 850 | |
| 851 | /************************************************* |
| 852 | * Initialize for incoming batched SMTP message * |
| 853 | *************************************************/ |
| 854 | |
| 855 | /* This function is called from smtp_setup_msg() in the case when |
| 856 | smtp_batched_input is true. This happens when -bS is used to pass a whole batch |
| 857 | of messages in one file with SMTP commands between them. All errors must be |
| 858 | reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are |
| 859 | relevant. After an error on a sender, or an invalid recipient, the remainder |
| 860 | of the message is skipped. The value of received_protocol is already set. |
| 861 | |
| 862 | Argument: none |
| 863 | Returns: > 0 message successfully started (reached DATA) |
| 864 | = 0 QUIT read or end of file reached |
| 865 | < 0 should not occur |
| 866 | */ |
| 867 | |
| 868 | static int |
| 869 | smtp_setup_batch_msg(void) |
| 870 | { |
| 871 | int done = 0; |
| 872 | void *reset_point = store_get(0); |
| 873 | |
| 874 | /* Save the line count at the start of each transaction - single commands |
| 875 | like HELO and RSET count as whole transactions. */ |
| 876 | |
| 877 | bsmtp_transaction_linecount = receive_linecount; |
| 878 | |
| 879 | if ((receive_feof)()) return 0; /* Treat EOF as QUIT */ |
| 880 | |
| 881 | smtp_reset(reset_point); /* Reset for start of message */ |
| 882 | |
| 883 | /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE |
| 884 | value. The values are 2 larger than the required yield of the function. */ |
| 885 | |
| 886 | while (done <= 0) |
| 887 | { |
| 888 | uschar *errmess; |
| 889 | uschar *recipient = NULL; |
| 890 | int start, end, sender_domain, recipient_domain; |
| 891 | |
| 892 | switch(smtp_read_command(FALSE)) |
| 893 | { |
| 894 | /* The HELO/EHLO commands set sender_address_helo if they have |
| 895 | valid data; otherwise they are ignored, except that they do |
| 896 | a reset of the state. */ |
| 897 | |
| 898 | case HELO_CMD: |
| 899 | case EHLO_CMD: |
| 900 | |
| 901 | check_helo(smtp_data); |
| 902 | /* Fall through */ |
| 903 | |
| 904 | case RSET_CMD: |
| 905 | smtp_reset(reset_point); |
| 906 | bsmtp_transaction_linecount = receive_linecount; |
| 907 | break; |
| 908 | |
| 909 | |
| 910 | /* The MAIL FROM command requires an address as an operand. All we |
| 911 | do here is to parse it for syntactic correctness. The form "<>" is |
| 912 | a special case which converts into an empty string. The start/end |
| 913 | pointers in the original are not used further for this address, as |
| 914 | it is the canonical extracted address which is all that is kept. */ |
| 915 | |
| 916 | case MAIL_CMD: |
| 917 | if (sender_address != NULL) |
| 918 | /* The function moan_smtp_batch() does not return. */ |
| 919 | moan_smtp_batch(cmd_buffer, "503 Sender already given"); |
| 920 | |
| 921 | if (smtp_data[0] == 0) |
| 922 | /* The function moan_smtp_batch() does not return. */ |
| 923 | moan_smtp_batch(cmd_buffer, "501 MAIL FROM must have an address operand"); |
| 924 | |
| 925 | /* Reset to start of message */ |
| 926 | |
| 927 | smtp_reset(reset_point); |
| 928 | |
| 929 | /* Apply SMTP rewrite */ |
| 930 | |
| 931 | raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)? |
| 932 | rewrite_one(smtp_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE, |
| 933 | US"", global_rewrite_rules) : smtp_data; |
| 934 | |
| 935 | /* Extract the address; the TRUE flag allows <> as valid */ |
| 936 | |
| 937 | raw_sender = |
| 938 | parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain, |
| 939 | TRUE); |
| 940 | |
| 941 | if (raw_sender == NULL) |
| 942 | /* The function moan_smtp_batch() does not return. */ |
| 943 | moan_smtp_batch(cmd_buffer, "501 %s", errmess); |
| 944 | |
| 945 | sender_address = string_copy(raw_sender); |
| 946 | |
| 947 | /* Qualify unqualified sender addresses if permitted to do so. */ |
| 948 | |
| 949 | if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@') |
| 950 | { |
| 951 | if (allow_unqualified_sender) |
| 952 | { |
| 953 | sender_address = rewrite_address_qualify(sender_address, FALSE); |
| 954 | DEBUG(D_receive) debug_printf("unqualified address %s accepted " |
| 955 | "and rewritten\n", raw_sender); |
| 956 | } |
| 957 | /* The function moan_smtp_batch() does not return. */ |
| 958 | else moan_smtp_batch(cmd_buffer, "501 sender address must contain " |
| 959 | "a domain"); |
| 960 | } |
| 961 | break; |
| 962 | |
| 963 | |
| 964 | /* The RCPT TO command requires an address as an operand. All we do |
| 965 | here is to parse it for syntactic correctness. There may be any number |
| 966 | of RCPT TO commands, specifying multiple senders. We build them all into |
| 967 | a data structure that is in argc/argv format. The start/end values |
| 968 | given by parse_extract_address are not used, as we keep only the |
| 969 | extracted address. */ |
| 970 | |
| 971 | case RCPT_CMD: |
| 972 | if (sender_address == NULL) |
| 973 | /* The function moan_smtp_batch() does not return. */ |
| 974 | moan_smtp_batch(cmd_buffer, "503 No sender yet given"); |
| 975 | |
| 976 | if (smtp_data[0] == 0) |
| 977 | /* The function moan_smtp_batch() does not return. */ |
| 978 | moan_smtp_batch(cmd_buffer, "501 RCPT TO must have an address operand"); |
| 979 | |
| 980 | /* Check maximum number allowed */ |
| 981 | |
| 982 | if (recipients_max > 0 && recipients_count + 1 > recipients_max) |
| 983 | /* The function moan_smtp_batch() does not return. */ |
| 984 | moan_smtp_batch(cmd_buffer, "%s too many recipients", |
| 985 | recipients_max_reject? "552": "452"); |
| 986 | |
| 987 | /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a |
| 988 | recipient address */ |
| 989 | |
| 990 | recipient = ((rewrite_existflags & rewrite_smtp) != 0)? |
| 991 | rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"", |
| 992 | global_rewrite_rules) : smtp_data; |
| 993 | |
| 994 | /* rfc821_domains = TRUE; << no longer needed */ |
| 995 | recipient = parse_extract_address(recipient, &errmess, &start, &end, |
| 996 | &recipient_domain, FALSE); |
| 997 | /* rfc821_domains = FALSE; << no longer needed */ |
| 998 | |
| 999 | if (recipient == NULL) |
| 1000 | /* The function moan_smtp_batch() does not return. */ |
| 1001 | moan_smtp_batch(cmd_buffer, "501 %s", errmess); |
| 1002 | |
| 1003 | /* If the recipient address is unqualified, qualify it if permitted. Then |
| 1004 | add it to the list of recipients. */ |
| 1005 | |
| 1006 | if (recipient_domain == 0) |
| 1007 | { |
| 1008 | if (allow_unqualified_recipient) |
| 1009 | { |
| 1010 | DEBUG(D_receive) debug_printf("unqualified address %s accepted\n", |
| 1011 | recipient); |
| 1012 | recipient = rewrite_address_qualify(recipient, TRUE); |
| 1013 | } |
| 1014 | /* The function moan_smtp_batch() does not return. */ |
| 1015 | else moan_smtp_batch(cmd_buffer, "501 recipient address must contain " |
| 1016 | "a domain"); |
| 1017 | } |
| 1018 | receive_add_recipient(recipient, -1); |
| 1019 | break; |
| 1020 | |
| 1021 | |
| 1022 | /* The DATA command is legal only if it follows successful MAIL FROM |
| 1023 | and RCPT TO commands. This function is complete when a valid DATA |
| 1024 | command is encountered. */ |
| 1025 | |
| 1026 | case DATA_CMD: |
| 1027 | if (sender_address == NULL || recipients_count <= 0) |
| 1028 | { |
| 1029 | /* The function moan_smtp_batch() does not return. */ |
| 1030 | if (sender_address == NULL) |
| 1031 | moan_smtp_batch(cmd_buffer, |
| 1032 | "503 MAIL FROM:<sender> command must precede DATA"); |
| 1033 | else |
| 1034 | moan_smtp_batch(cmd_buffer, |
| 1035 | "503 RCPT TO:<recipient> must precede DATA"); |
| 1036 | } |
| 1037 | else |
| 1038 | { |
| 1039 | done = 3; /* DATA successfully achieved */ |
| 1040 | message_ended = END_NOTENDED; /* Indicate in middle of message */ |
| 1041 | } |
| 1042 | break; |
| 1043 | |
| 1044 | |
| 1045 | /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */ |
| 1046 | |
| 1047 | case VRFY_CMD: |
| 1048 | case EXPN_CMD: |
| 1049 | case HELP_CMD: |
| 1050 | case NOOP_CMD: |
| 1051 | case ETRN_CMD: |
| 1052 | bsmtp_transaction_linecount = receive_linecount; |
| 1053 | break; |
| 1054 | |
| 1055 | |
| 1056 | case EOF_CMD: |
| 1057 | case QUIT_CMD: |
| 1058 | done = 2; |
| 1059 | break; |
| 1060 | |
| 1061 | |
| 1062 | case BADARG_CMD: |
| 1063 | /* The function moan_smtp_batch() does not return. */ |
| 1064 | moan_smtp_batch(cmd_buffer, "501 Unexpected argument data"); |
| 1065 | break; |
| 1066 | |
| 1067 | |
| 1068 | case BADCHAR_CMD: |
| 1069 | /* The function moan_smtp_batch() does not return. */ |
| 1070 | moan_smtp_batch(cmd_buffer, "501 Unexpected NULL in SMTP command"); |
| 1071 | break; |
| 1072 | |
| 1073 | |
| 1074 | default: |
| 1075 | /* The function moan_smtp_batch() does not return. */ |
| 1076 | moan_smtp_batch(cmd_buffer, "500 Command unrecognized"); |
| 1077 | break; |
| 1078 | } |
| 1079 | } |
| 1080 | |
| 1081 | return done - 2; /* Convert yield values */ |
| 1082 | } |
| 1083 | |
| 1084 | |
| 1085 | |
| 1086 | |
| 1087 | /************************************************* |
| 1088 | * Start an SMTP session * |
| 1089 | *************************************************/ |
| 1090 | |
| 1091 | /* This function is called at the start of an SMTP session. Thereafter, |
| 1092 | smtp_setup_msg() is called to initiate each separate message. This |
| 1093 | function does host-specific testing, and outputs the banner line. |
| 1094 | |
| 1095 | Arguments: none |
| 1096 | Returns: FALSE if the session can not continue; something has |
| 1097 | gone wrong, or the connection to the host is blocked |
| 1098 | */ |
| 1099 | |
| 1100 | BOOL |
| 1101 | smtp_start_session(void) |
| 1102 | { |
| 1103 | int size = 256; |
| 1104 | int i, ptr; |
| 1105 | uschar *p, *s, *ss; |
| 1106 | |
| 1107 | helo_seen = esmtp = helo_accept_junk = FALSE; |
| 1108 | count_nonmail = TRUE_UNSET; |
| 1109 | synprot_error_count = unknown_command_count = nonmail_command_count = 0; |
| 1110 | smtp_delay_mail = smtp_rlm_base; |
| 1111 | auth_advertised = FALSE; |
| 1112 | pipelining_advertised = FALSE; |
| 1113 | sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING; |
| 1114 | |
| 1115 | memset(sender_host_cache, 0, sizeof(sender_host_cache)); |
| 1116 | |
| 1117 | sender_host_authenticated = NULL; |
| 1118 | authenticated_by = NULL; |
| 1119 | |
| 1120 | #ifdef SUPPORT_TLS |
| 1121 | tls_cipher = tls_peerdn = NULL; |
| 1122 | tls_advertised = FALSE; |
| 1123 | #endif |
| 1124 | |
| 1125 | /* Reset ACL connection variables */ |
| 1126 | |
| 1127 | for (i = 0; i < ACL_C_MAX; i++) acl_var[i] = NULL; |
| 1128 | |
| 1129 | cmd_buffer = (uschar *)malloc(cmd_buffer_size + 1); /* allow for trailing 0 */ |
| 1130 | if (cmd_buffer == NULL) |
| 1131 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, |
| 1132 | "malloc() failed for SMTP command buffer"); |
| 1133 | |
| 1134 | /* For batched input, the protocol setting can be overridden from the |
| 1135 | command line by a trusted caller. */ |
| 1136 | |
| 1137 | if (smtp_batched_input) |
| 1138 | { |
| 1139 | if (received_protocol == NULL) received_protocol = US"local-bsmtp"; |
| 1140 | } |
| 1141 | |
| 1142 | /* For non-batched SMTP input, the protocol setting is forced here. It will be |
| 1143 | reset later if any of EHLO/AUTH/STARTTLS are received. */ |
| 1144 | |
| 1145 | else |
| 1146 | received_protocol = |
| 1147 | protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0); |
| 1148 | |
| 1149 | /* Set up the buffer for inputting using direct read() calls, and arrange to |
| 1150 | call the local functions instead of the standard C ones. */ |
| 1151 | |
| 1152 | smtp_inbuffer = (uschar *)malloc(in_buffer_size); |
| 1153 | if (smtp_inbuffer == NULL) |
| 1154 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer"); |
| 1155 | receive_getc = smtp_getc; |
| 1156 | receive_ungetc = smtp_ungetc; |
| 1157 | receive_feof = smtp_feof; |
| 1158 | receive_ferror = smtp_ferror; |
| 1159 | smtp_inptr = smtp_inend = smtp_inbuffer; |
| 1160 | smtp_had_eof = smtp_had_error = 0; |
| 1161 | |
| 1162 | /* Set up the message size limit; this may be host-specific */ |
| 1163 | |
| 1164 | thismessage_size_limit = expand_string_integer(message_size_limit); |
| 1165 | if (thismessage_size_limit < 0) |
| 1166 | { |
| 1167 | if (thismessage_size_limit == -1) |
| 1168 | log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: " |
| 1169 | "%s", expand_string_message); |
| 1170 | else |
| 1171 | log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: " |
| 1172 | "%s", expand_string_message); |
| 1173 | smtp_closedown(US"Temporary local problem - please try later"); |
| 1174 | return FALSE; |
| 1175 | } |
| 1176 | |
| 1177 | /* When a message is input locally via the -bs or -bS options, sender_host_ |
| 1178 | unknown is set unless -oMa was used to force an IP address, in which case it |
| 1179 | is checked like a real remote connection. When -bs is used from inetd, this |
| 1180 | flag is not set, causing the sending host to be checked. The code that deals |
| 1181 | with IP source routing (if configured) is never required for -bs or -bS and |
| 1182 | the flag sender_host_notsocket is used to suppress it. |
| 1183 | |
| 1184 | If smtp_accept_max and smtp_accept_reserve are set, keep some connections in |
| 1185 | reserve for certain hosts and/or networks. */ |
| 1186 | |
| 1187 | if (!sender_host_unknown) |
| 1188 | { |
| 1189 | int rc; |
| 1190 | BOOL reserved_host = FALSE; |
| 1191 | |
| 1192 | /* Look up IP options (source routing info) on the socket if this is not an |
| 1193 | -oMa "host", and if any are found, log them and drop the connection. |
| 1194 | |
| 1195 | Linux (and others now, see below) is different to everyone else, so there |
| 1196 | has to be some conditional compilation here. Versions of Linux before 2.1.15 |
| 1197 | used a structure whose name was "options". Somebody finally realized that |
| 1198 | this name was silly, and it got changed to "ip_options". I use the |
| 1199 | newer name here, but there is a fudge in the script that sets up os.h |
| 1200 | to define a macro in older Linux systems. |
| 1201 | |
| 1202 | Sigh. Linux is a fast-moving target. Another generation of Linux uses |
| 1203 | glibc 2, which has chosen ip_opts for the structure name. This is now |
| 1204 | really a glibc thing rather than a Linux thing, so the condition name |
| 1205 | has been changed to reflect this. It is relevant also to GNU/Hurd. |
| 1206 | |
| 1207 | Mac OS 10.x (Darwin) is like the later glibc versions, but without the |
| 1208 | setting of the __GLIBC__ macro, so we can't detect it automatically. There's |
| 1209 | a special macro defined in the os.h file. |
| 1210 | |
| 1211 | Some DGUX versions on older hardware appear not to support IP options at |
| 1212 | all, so there is now a general macro which can be set to cut out this |
| 1213 | support altogether. |
| 1214 | |
| 1215 | How to do this properly in IPv6 is not yet known. */ |
| 1216 | |
| 1217 | #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS) |
| 1218 | |
| 1219 | #ifdef GLIBC_IP_OPTIONS |
| 1220 | #if (!defined __GLIBC__) || (__GLIBC__ < 2) |
| 1221 | #define OPTSTYLE 1 |
| 1222 | #else |
| 1223 | #define OPTSTYLE 2 |
| 1224 | #endif |
| 1225 | #elif defined DARWIN_IP_OPTIONS |
| 1226 | #define OPTSTYLE 2 |
| 1227 | #else |
| 1228 | #define OPTSTYLE 3 |
| 1229 | #endif |
| 1230 | |
| 1231 | if (!host_checking && !sender_host_notsocket) |
| 1232 | { |
| 1233 | #if OPTSTYLE == 1 |
| 1234 | SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN; |
| 1235 | struct ip_options *ipopt = store_get(optlen); |
| 1236 | #elif OPTSTYLE == 2 |
| 1237 | struct ip_opts ipoptblock; |
| 1238 | struct ip_opts *ipopt = &ipoptblock; |
| 1239 | SOCKLEN_T optlen = sizeof(ipoptblock); |
| 1240 | #else |
| 1241 | struct ipoption ipoptblock; |
| 1242 | struct ipoption *ipopt = &ipoptblock; |
| 1243 | SOCKLEN_T optlen = sizeof(ipoptblock); |
| 1244 | #endif |
| 1245 | |
| 1246 | /* Occasional genuine failures of getsockopt() have been seen - for |
| 1247 | example, "reset by peer". Therefore, just log and give up on this |
| 1248 | call, unless the error is ENOPROTOOPT. This error is given by systems |
| 1249 | that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time |
| 1250 | of writing. So for that error, carry on - we just can't do an IP options |
| 1251 | check. */ |
| 1252 | |
| 1253 | DEBUG(D_receive) debug_printf("checking for IP options\n"); |
| 1254 | |
| 1255 | if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt), |
| 1256 | &optlen) < 0) |
| 1257 | { |
| 1258 | if (errno != ENOPROTOOPT) |
| 1259 | { |
| 1260 | log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s", |
| 1261 | host_and_ident(FALSE), strerror(errno)); |
| 1262 | smtp_printf("451 SMTP service not available\r\n"); |
| 1263 | return FALSE; |
| 1264 | } |
| 1265 | } |
| 1266 | |
| 1267 | /* Deal with any IP options that are set. On the systems I have looked at, |
| 1268 | the value of MAX_IPOPTLEN has been 40, meaning that there should never be |
| 1269 | more logging data than will fit in big_buffer. Nevertheless, after somebody |
| 1270 | questioned this code, I've added in some paranoid checking. */ |
| 1271 | |
| 1272 | else if (optlen > 0) |
| 1273 | { |
| 1274 | uschar *p = big_buffer; |
| 1275 | uschar *pend = big_buffer + big_buffer_size; |
| 1276 | uschar *opt, *adptr; |
| 1277 | int optcount; |
| 1278 | struct in_addr addr; |
| 1279 | |
| 1280 | #if OPTSTYLE == 1 |
| 1281 | uschar *optstart = (uschar *)(ipopt->__data); |
| 1282 | #elif OPTSTYLE == 2 |
| 1283 | uschar *optstart = (uschar *)(ipopt->ip_opts); |
| 1284 | #else |
| 1285 | uschar *optstart = (uschar *)(ipopt->ipopt_list); |
| 1286 | #endif |
| 1287 | |
| 1288 | DEBUG(D_receive) debug_printf("IP options exist\n"); |
| 1289 | |
| 1290 | Ustrcpy(p, "IP options on incoming call:"); |
| 1291 | p += Ustrlen(p); |
| 1292 | |
| 1293 | for (opt = optstart; opt != NULL && |
| 1294 | opt < (uschar *)(ipopt) + optlen;) |
| 1295 | { |
| 1296 | switch (*opt) |
| 1297 | { |
| 1298 | case IPOPT_EOL: |
| 1299 | opt = NULL; |
| 1300 | break; |
| 1301 | |
| 1302 | case IPOPT_NOP: |
| 1303 | opt++; |
| 1304 | break; |
| 1305 | |
| 1306 | case IPOPT_SSRR: |
| 1307 | case IPOPT_LSRR: |
| 1308 | if (!string_format(p, pend-p, " %s [@%s", |
| 1309 | (*opt == IPOPT_SSRR)? "SSRR" : "LSRR", |
| 1310 | #if OPTSTYLE == 1 |
| 1311 | inet_ntoa(*((struct in_addr *)(&(ipopt->faddr)))))) |
| 1312 | #elif OPTSTYLE == 2 |
| 1313 | inet_ntoa(ipopt->ip_dst))) |
| 1314 | #else |
| 1315 | inet_ntoa(ipopt->ipopt_dst))) |
| 1316 | #endif |
| 1317 | { |
| 1318 | opt = NULL; |
| 1319 | break; |
| 1320 | } |
| 1321 | |
| 1322 | p += Ustrlen(p); |
| 1323 | optcount = (opt[1] - 3) / sizeof(struct in_addr); |
| 1324 | adptr = opt + 3; |
| 1325 | while (optcount-- > 0) |
| 1326 | { |
| 1327 | memcpy(&addr, adptr, sizeof(addr)); |
| 1328 | if (!string_format(p, pend - p - 1, "%s%s", |
| 1329 | (optcount == 0)? ":" : "@", inet_ntoa(addr))) |
| 1330 | { |
| 1331 | opt = NULL; |
| 1332 | break; |
| 1333 | } |
| 1334 | p += Ustrlen(p); |
| 1335 | adptr += sizeof(struct in_addr); |
| 1336 | } |
| 1337 | *p++ = ']'; |
| 1338 | opt += opt[1]; |
| 1339 | break; |
| 1340 | |
| 1341 | default: |
| 1342 | { |
| 1343 | int i; |
| 1344 | if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; } |
| 1345 | Ustrcat(p, "[ "); |
| 1346 | p += 2; |
| 1347 | for (i = 0; i < opt[1]; i++) |
| 1348 | { |
| 1349 | sprintf(CS p, "%2.2x ", opt[i]); |
| 1350 | p += 3; |
| 1351 | } |
| 1352 | *p++ = ']'; |
| 1353 | } |
| 1354 | opt += opt[1]; |
| 1355 | break; |
| 1356 | } |
| 1357 | } |
| 1358 | |
| 1359 | *p = 0; |
| 1360 | log_write(0, LOG_MAIN, "%s", big_buffer); |
| 1361 | |
| 1362 | /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */ |
| 1363 | |
| 1364 | log_write(0, LOG_MAIN|LOG_REJECT, |
| 1365 | "connection from %s refused (IP options)", host_and_ident(FALSE)); |
| 1366 | |
| 1367 | smtp_printf("554 SMTP service not available\r\n"); |
| 1368 | return FALSE; |
| 1369 | } |
| 1370 | |
| 1371 | /* Length of options = 0 => there are no options */ |
| 1372 | |
| 1373 | else DEBUG(D_receive) debug_printf("no IP options found\n"); |
| 1374 | } |
| 1375 | #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */ |
| 1376 | |
| 1377 | /* Set keep-alive in socket options. The option is on by default. This |
| 1378 | setting is an attempt to get rid of some hanging connections that stick in |
| 1379 | read() when the remote end (usually a dialup) goes away. */ |
| 1380 | |
| 1381 | if (smtp_accept_keepalive && !sender_host_notsocket) |
| 1382 | ip_keepalive(fileno(smtp_out), sender_host_address, FALSE); |
| 1383 | |
| 1384 | /* If the current host matches host_lookup, set the name by doing a |
| 1385 | reverse lookup. On failure, sender_host_name will be NULL and |
| 1386 | host_lookup_failed will be TRUE. This may or may not be serious - optional |
| 1387 | checks later. */ |
| 1388 | |
| 1389 | if (verify_check_host(&host_lookup) == OK) |
| 1390 | { |
| 1391 | (void)host_name_lookup(); |
| 1392 | host_build_sender_fullhost(); |
| 1393 | } |
| 1394 | |
| 1395 | /* Delay this until we have the full name, if it is looked up. */ |
| 1396 | |
| 1397 | set_process_info("handling incoming connection from %s", |
| 1398 | host_and_ident(FALSE)); |
| 1399 | |
| 1400 | /* Start up TLS if tls_on_connect is set. This is for supporting the legacy |
| 1401 | smtps port for use with older style SSL MTAs. */ |
| 1402 | |
| 1403 | #ifdef SUPPORT_TLS |
| 1404 | if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK) |
| 1405 | return FALSE; |
| 1406 | #endif |
| 1407 | |
| 1408 | /* Test for explicit connection rejection */ |
| 1409 | |
| 1410 | if (verify_check_host(&host_reject_connection) == OK) |
| 1411 | { |
| 1412 | log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection " |
| 1413 | "from %s (host_reject_connection)", host_and_ident(FALSE)); |
| 1414 | smtp_printf("554 SMTP service not available\r\n"); |
| 1415 | return FALSE; |
| 1416 | } |
| 1417 | |
| 1418 | /* Test with TCP Wrappers if so configured */ |
| 1419 | |
| 1420 | #ifdef USE_TCP_WRAPPERS |
| 1421 | if (!hosts_ctl("exim", |
| 1422 | (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name, |
| 1423 | (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address, |
| 1424 | (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident)) |
| 1425 | { |
| 1426 | HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n"); |
| 1427 | log_write(L_connection_reject, |
| 1428 | LOG_MAIN|LOG_REJECT, "refused connection from %s " |
| 1429 | "(tcp wrappers)", host_and_ident(FALSE)); |
| 1430 | smtp_printf("554 SMTP service not available\r\n"); |
| 1431 | return FALSE; |
| 1432 | } |
| 1433 | #endif |
| 1434 | |
| 1435 | /* Check for reserved slots. Note that the count value doesn't include |
| 1436 | this process, as it gets upped in the parent process. */ |
| 1437 | |
| 1438 | if (smtp_accept_max > 0 && |
| 1439 | smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve) |
| 1440 | { |
| 1441 | if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK) |
| 1442 | { |
| 1443 | log_write(L_connection_reject, |
| 1444 | LOG_MAIN, "temporarily refused connection from %s: not in " |
| 1445 | "reserve list: connected=%d max=%d reserve=%d%s", |
| 1446 | host_and_ident(FALSE), smtp_accept_count, smtp_accept_max, |
| 1447 | smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : ""); |
| 1448 | smtp_printf("421 %s: Too many concurrent SMTP connections; " |
| 1449 | "please try again later\r\n", smtp_active_hostname); |
| 1450 | return FALSE; |
| 1451 | } |
| 1452 | reserved_host = TRUE; |
| 1453 | } |
| 1454 | |
| 1455 | /* If a load level above which only messages from reserved hosts are |
| 1456 | accepted is set, check the load. For incoming calls via the daemon, the |
| 1457 | check is done in the superior process if there are no reserved hosts, to |
| 1458 | save a fork. In all cases, the load average will already be available |
| 1459 | in a global variable at this point. */ |
| 1460 | |
| 1461 | if (smtp_load_reserve >= 0 && |
| 1462 | load_average > smtp_load_reserve && |
| 1463 | !reserved_host && |
| 1464 | verify_check_host(&smtp_reserve_hosts) != OK) |
| 1465 | { |
| 1466 | log_write(L_connection_reject, |
| 1467 | LOG_MAIN, "temporarily refused connection from %s: not in " |
| 1468 | "reserve list and load average = %.2f", host_and_ident(FALSE), |
| 1469 | (double)load_average/1000.0); |
| 1470 | smtp_printf("421 %s: Too much load; please try again later\r\n", |
| 1471 | smtp_active_hostname); |
| 1472 | return FALSE; |
| 1473 | } |
| 1474 | |
| 1475 | /* Determine whether unqualified senders or recipients are permitted |
| 1476 | for this host. Unfortunately, we have to do this every time, in order to |
| 1477 | set the flags so that they can be inspected when considering qualifying |
| 1478 | addresses in the headers. For a site that permits no qualification, this |
| 1479 | won't take long, however. */ |
| 1480 | |
| 1481 | allow_unqualified_sender = |
| 1482 | verify_check_host(&sender_unqualified_hosts) == OK; |
| 1483 | |
| 1484 | allow_unqualified_recipient = |
| 1485 | verify_check_host(&recipient_unqualified_hosts) == OK; |
| 1486 | |
| 1487 | /* Determine whether HELO/EHLO is required for this host. The requirement |
| 1488 | can be hard or soft. */ |
| 1489 | |
| 1490 | helo_required = verify_check_host(&helo_verify_hosts) == OK; |
| 1491 | if (!helo_required) |
| 1492 | helo_verify = verify_check_host(&helo_try_verify_hosts) == OK; |
| 1493 | |
| 1494 | /* Determine whether this hosts is permitted to send syntactic junk |
| 1495 | after a HELO or EHLO command. */ |
| 1496 | |
| 1497 | helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK; |
| 1498 | } |
| 1499 | |
| 1500 | /* For batch SMTP input we are now done. */ |
| 1501 | |
| 1502 | if (smtp_batched_input) return TRUE; |
| 1503 | |
| 1504 | /* Run the ACL if it exists */ |
| 1505 | |
| 1506 | if (acl_smtp_connect != NULL) |
| 1507 | { |
| 1508 | int rc; |
| 1509 | uschar *user_msg, *log_msg; |
| 1510 | smtp_data = US"in \"connect\" ACL"; /* For logged failure message */ |
| 1511 | rc = acl_check(ACL_WHERE_CONNECT, US"", acl_smtp_connect, &user_msg, |
| 1512 | &log_msg); |
| 1513 | if (rc != OK) |
| 1514 | { |
| 1515 | (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg); |
| 1516 | return FALSE; |
| 1517 | } |
| 1518 | } |
| 1519 | |
| 1520 | /* Output the initial message for a two-way SMTP connection. It may contain |
| 1521 | newlines, which then cause a multi-line response to be given. */ |
| 1522 | |
| 1523 | s = expand_string(smtp_banner); |
| 1524 | if (s == NULL) |
| 1525 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) " |
| 1526 | "failed: %s", smtp_banner, expand_string_message); |
| 1527 | |
| 1528 | /* Remove any terminating newlines; might as well remove trailing space too */ |
| 1529 | |
| 1530 | p = s + Ustrlen(s); |
| 1531 | while (p > s && isspace(p[-1])) p--; |
| 1532 | *p = 0; |
| 1533 | |
| 1534 | /* It seems that CC:Mail is braindead, and assumes that the greeting message |
| 1535 | is all contained in a single IP packet. The original code wrote out the |
| 1536 | greeting using several calls to fprint/fputc, and on busy servers this could |
| 1537 | cause it to be split over more than one packet - which caused CC:Mail to fall |
| 1538 | over when it got the second part of the greeting after sending its first |
| 1539 | command. Sigh. To try to avoid this, build the complete greeting message |
| 1540 | first, and output it in one fell swoop. This gives a better chance of it |
| 1541 | ending up as a single packet. */ |
| 1542 | |
| 1543 | ss = store_get(size); |
| 1544 | ptr = 0; |
| 1545 | |
| 1546 | p = s; |
| 1547 | do /* At least once, in case we have an empty string */ |
| 1548 | { |
| 1549 | int len; |
| 1550 | uschar *linebreak = Ustrchr(p, '\n'); |
| 1551 | if (linebreak == NULL) |
| 1552 | { |
| 1553 | len = Ustrlen(p); |
| 1554 | ss = string_cat(ss, &size, &ptr, US"220 ", 4); |
| 1555 | } |
| 1556 | else |
| 1557 | { |
| 1558 | len = linebreak - p; |
| 1559 | ss = string_cat(ss, &size, &ptr, US"220-", 4); |
| 1560 | } |
| 1561 | ss = string_cat(ss, &size, &ptr, p, len); |
| 1562 | ss = string_cat(ss, &size, &ptr, US"\r\n", 2); |
| 1563 | p += len; |
| 1564 | if (linebreak != NULL) p++; |
| 1565 | } |
| 1566 | while (*p != 0); |
| 1567 | |
| 1568 | ss[ptr] = 0; /* string_cat leaves room for this */ |
| 1569 | |
| 1570 | /* Before we write the banner, check that there is no input pending, unless |
| 1571 | this synchronisation check is disabled. */ |
| 1572 | |
| 1573 | if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket) |
| 1574 | { |
| 1575 | fd_set fds; |
| 1576 | struct timeval tzero; |
| 1577 | tzero.tv_sec = 0; |
| 1578 | tzero.tv_usec = 0; |
| 1579 | FD_ZERO(&fds); |
| 1580 | FD_SET(fileno(smtp_in), &fds); |
| 1581 | if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, |
| 1582 | &tzero) > 0) |
| 1583 | { |
| 1584 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: " |
| 1585 | "synchronization error (input sent without waiting for greeting): " |
| 1586 | "rejected connection from %s", host_and_ident(TRUE)); |
| 1587 | smtp_printf("554 SMTP synchronization error\r\n"); |
| 1588 | return FALSE; |
| 1589 | } |
| 1590 | } |
| 1591 | |
| 1592 | /* Now output the banner */ |
| 1593 | |
| 1594 | smtp_printf("%s", ss); |
| 1595 | return TRUE; |
| 1596 | } |
| 1597 | |
| 1598 | |
| 1599 | |
| 1600 | |
| 1601 | |
| 1602 | /************************************************* |
| 1603 | * Handle SMTP syntax and protocol errors * |
| 1604 | *************************************************/ |
| 1605 | |
| 1606 | /* Write to the log for SMTP syntax errors in incoming commands, if configured |
| 1607 | to do so. Then transmit the error response. The return value depends on the |
| 1608 | number of syntax and protocol errors in this SMTP session. |
| 1609 | |
| 1610 | Arguments: |
| 1611 | type error type, given as a log flag bit |
| 1612 | code response code; <= 0 means don't send a response |
| 1613 | data data to reflect in the response (can be NULL) |
| 1614 | errmess the error message |
| 1615 | |
| 1616 | Returns: -1 limit of syntax/protocol errors NOT exceeded |
| 1617 | +1 limit of syntax/protocol errors IS exceeded |
| 1618 | |
| 1619 | These values fit in with the values of the "done" variable in the main |
| 1620 | processing loop in smtp_setup_msg(). */ |
| 1621 | |
| 1622 | static int |
| 1623 | synprot_error(int type, int code, uschar *data, uschar *errmess) |
| 1624 | { |
| 1625 | int yield = -1; |
| 1626 | |
| 1627 | log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s", |
| 1628 | (type == L_smtp_syntax_error)? "syntax" : "protocol", |
| 1629 | string_printing(cmd_buffer), host_and_ident(TRUE), errmess); |
| 1630 | |
| 1631 | if (++synprot_error_count > smtp_max_synprot_errors) |
| 1632 | { |
| 1633 | yield = 1; |
| 1634 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " |
| 1635 | "syntax or protocol errors (last command was \"%s\")", |
| 1636 | host_and_ident(FALSE), cmd_buffer); |
| 1637 | } |
| 1638 | |
| 1639 | if (code > 0) |
| 1640 | { |
| 1641 | smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ', |
| 1642 | (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess); |
| 1643 | if (yield == 1) |
| 1644 | smtp_printf("%d Too many syntax or protocol errors\r\n", code); |
| 1645 | } |
| 1646 | |
| 1647 | return yield; |
| 1648 | } |
| 1649 | |
| 1650 | |
| 1651 | |
| 1652 | |
| 1653 | /************************************************* |
| 1654 | * Log incomplete transactions * |
| 1655 | *************************************************/ |
| 1656 | |
| 1657 | /* This function is called after a transaction has been aborted by RSET, QUIT, |
| 1658 | connection drops or other errors. It logs the envelope information received |
| 1659 | so far in order to preserve address verification attempts. |
| 1660 | |
| 1661 | Argument: string to indicate what aborted the transaction |
| 1662 | Returns: nothing |
| 1663 | */ |
| 1664 | |
| 1665 | static void |
| 1666 | incomplete_transaction_log(uschar *what) |
| 1667 | { |
| 1668 | if (sender_address == NULL || /* No transaction in progress */ |
| 1669 | (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */ |
| 1670 | ) return; |
| 1671 | |
| 1672 | /* Build list of recipients for logging */ |
| 1673 | |
| 1674 | if (recipients_count > 0) |
| 1675 | { |
| 1676 | int i; |
| 1677 | raw_recipients = store_get(recipients_count * sizeof(uschar *)); |
| 1678 | for (i = 0; i < recipients_count; i++) |
| 1679 | raw_recipients[i] = recipients_list[i].address; |
| 1680 | raw_recipients_count = recipients_count; |
| 1681 | } |
| 1682 | |
| 1683 | log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS, |
| 1684 | "%s incomplete transaction (%s)", host_and_ident(TRUE), what); |
| 1685 | } |
| 1686 | |
| 1687 | |
| 1688 | |
| 1689 | |
| 1690 | /************************************************* |
| 1691 | * Send SMTP response, possibly multiline * |
| 1692 | *************************************************/ |
| 1693 | |
| 1694 | /* There are, it seems, broken clients out there that cannot handle multiline |
| 1695 | responses. If no_multiline_responses is TRUE (it can be set from an ACL), we |
| 1696 | output nothing for non-final calls, and only the first line for anything else. |
| 1697 | |
| 1698 | Arguments: |
| 1699 | code SMTP code |
| 1700 | final FALSE if the last line isn't the final line |
| 1701 | msg message text, possibly containing newlines |
| 1702 | |
| 1703 | Returns: nothing |
| 1704 | */ |
| 1705 | |
| 1706 | void |
| 1707 | smtp_respond(int code, BOOL final, uschar *msg) |
| 1708 | { |
| 1709 | if (!final && no_multiline_responses) return; |
| 1710 | |
| 1711 | for (;;) |
| 1712 | { |
| 1713 | uschar *nl = Ustrchr(msg, '\n'); |
| 1714 | if (nl == NULL) |
| 1715 | { |
| 1716 | smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg); |
| 1717 | return; |
| 1718 | } |
| 1719 | else if (nl[1] == 0 || no_multiline_responses) |
| 1720 | { |
| 1721 | smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg); |
| 1722 | return; |
| 1723 | } |
| 1724 | else |
| 1725 | { |
| 1726 | smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg); |
| 1727 | msg = nl + 1; |
| 1728 | while (isspace(*msg)) msg++; |
| 1729 | } |
| 1730 | } |
| 1731 | } |
| 1732 | |
| 1733 | |
| 1734 | |
| 1735 | |
| 1736 | /************************************************* |
| 1737 | * Handle an ACL failure * |
| 1738 | *************************************************/ |
| 1739 | |
| 1740 | /* This function is called when acl_check() fails. As well as calls from within |
| 1741 | this module, it is called from receive.c for an ACL after DATA. It sorts out |
| 1742 | logging the incident, and sets up the error response. A message containing |
| 1743 | newlines is turned into a multiline SMTP response, but for logging, only the |
| 1744 | first line is used. |
| 1745 | |
| 1746 | There's a table of the response codes to use in globals.c, along with the table |
| 1747 | of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim. |
| 1748 | However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded |
| 1749 | that the response should be 252 in the disabled state, because there are broken |
| 1750 | clients that try VRFY before RCPT. A 5xx response should be given only when the |
| 1751 | address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is |
| 1752 | given on refusal, and for AUTH, 503. |
| 1753 | |
| 1754 | Arguments: |
| 1755 | where where the ACL was called from |
| 1756 | rc the failure code |
| 1757 | user_msg a message that can be included in an SMTP response |
| 1758 | log_msg a message for logging |
| 1759 | |
| 1760 | Returns: 0 in most cases |
| 1761 | 2 if the failure code was FAIL_DROP, in which case the |
| 1762 | SMTP connection should be dropped (this value fits with the |
| 1763 | "done" variable in smtp_setup_msg() below) |
| 1764 | */ |
| 1765 | |
| 1766 | int |
| 1767 | smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg) |
| 1768 | { |
| 1769 | int code = acl_wherecodes[where]; |
| 1770 | BOOL drop = rc == FAIL_DROP; |
| 1771 | uschar *lognl; |
| 1772 | uschar *sender_info = US""; |
| 1773 | uschar *what = (where == ACL_WHERE_PREDATA)? US"DATA" : |
| 1774 | (where == ACL_WHERE_DATA)? US"after DATA" : |
| 1775 | string_sprintf("%s %s", acl_wherenames[where], smtp_data); |
| 1776 | |
| 1777 | if (drop) rc = FAIL; |
| 1778 | |
| 1779 | /* We used to have sender_address here; however, there was a bug that was not |
| 1780 | updating sender_address after a rewrite during a verify. When this bug was |
| 1781 | fixed, sender_address at this point became the rewritten address. I'm not sure |
| 1782 | this is what should be logged, so I've changed to logging the unrewritten |
| 1783 | address to retain backward compatibility. */ |
| 1784 | |
| 1785 | if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA) |
| 1786 | { |
| 1787 | sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)? |
| 1788 | sender_address_unrewritten : sender_address); |
| 1789 | } |
| 1790 | |
| 1791 | /* If there's been a sender verification failure with a specific message, and |
| 1792 | we have not sent a response about it yet, do so now, as a preliminary line for |
| 1793 | failures, but not defers. However, log it in both cases. */ |
| 1794 | |
| 1795 | if (sender_verified_failed != NULL && |
| 1796 | !testflag(sender_verified_failed, af_sverify_told)) |
| 1797 | { |
| 1798 | setflag(sender_verified_failed, af_sverify_told); |
| 1799 | |
| 1800 | log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s", |
| 1801 | host_and_ident(TRUE), |
| 1802 | ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail", |
| 1803 | sender_verified_failed->address, |
| 1804 | (sender_verified_failed->message == NULL)? US"" : |
| 1805 | string_sprintf(": %s", sender_verified_failed->message)); |
| 1806 | |
| 1807 | if (rc == FAIL && sender_verified_failed->user_message != NULL) |
| 1808 | smtp_respond(code, FALSE, string_sprintf( |
| 1809 | testflag(sender_verified_failed, af_verify_pmfail)? |
| 1810 | "Postmaster verification failed while checking <%s>\n%s\n" |
| 1811 | "Several RFCs state that you are required to have a postmaster\n" |
| 1812 | "mailbox for each mail domain. This host does not accept mail\n" |
| 1813 | "from domains whose servers reject the postmaster address." |
| 1814 | : |
| 1815 | testflag(sender_verified_failed, af_verify_nsfail)? |
| 1816 | "Callback setup failed while verifying <%s>\n%s\n" |
| 1817 | "The initial connection, or a HELO or MAIL FROM:<> command was\n" |
| 1818 | "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n" |
| 1819 | "RFC requirements, and stops you from receiving standard bounce\n" |
| 1820 | "messages. This host does not accept mail from domains whose servers\n" |
| 1821 | "refuse bounces." |
| 1822 | : |
| 1823 | "Verification failed for <%s>\n%s", |
| 1824 | sender_verified_failed->address, |
| 1825 | sender_verified_failed->user_message)); |
| 1826 | } |
| 1827 | |
| 1828 | /* Sort out text for logging */ |
| 1829 | |
| 1830 | log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg); |
| 1831 | lognl = Ustrchr(log_msg, '\n'); |
| 1832 | if (lognl != NULL) *lognl = 0; |
| 1833 | |
| 1834 | /* Send permanent failure response to the command, but the code used isn't |
| 1835 | always a 5xx one - see comments at the start of this function. If the original |
| 1836 | rc was FAIL_DROP we drop the connection and yield 2. */ |
| 1837 | |
| 1838 | if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)? |
| 1839 | US"Administrative prohibition" : user_msg); |
| 1840 | |
| 1841 | /* Send temporary failure response to the command. Don't give any details, |
| 1842 | unless acl_temp_details is set. This is TRUE for a callout defer, a "defer" |
| 1843 | verb, and for a header verify when smtp_return_error_details is set. |
| 1844 | |
| 1845 | This conditional logic is all somewhat of a mess because of the odd |
| 1846 | interactions between temp_details and return_error_details. One day it should |
| 1847 | be re-implemented in a tidier fashion. */ |
| 1848 | |
| 1849 | else |
| 1850 | { |
| 1851 | if (acl_temp_details && user_msg != NULL) |
| 1852 | { |
| 1853 | if (smtp_return_error_details && |
| 1854 | sender_verified_failed != NULL && |
| 1855 | sender_verified_failed->message != NULL) |
| 1856 | { |
| 1857 | smtp_respond(451, FALSE, sender_verified_failed->message); |
| 1858 | } |
| 1859 | smtp_respond(451, TRUE, user_msg); |
| 1860 | } |
| 1861 | else |
| 1862 | smtp_printf("451 Temporary local problem - please try later\r\n"); |
| 1863 | } |
| 1864 | |
| 1865 | /* Log the incident. If the connection is not forcibly to be dropped, return 0. |
| 1866 | Otherwise, log why it is closing if required and return 2. */ |
| 1867 | |
| 1868 | log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s", |
| 1869 | host_and_ident(TRUE), |
| 1870 | sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg); |
| 1871 | |
| 1872 | if (!drop) return 0; |
| 1873 | |
| 1874 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL", |
| 1875 | smtp_get_connection_info()); |
| 1876 | return 2; |
| 1877 | } |
| 1878 | |
| 1879 | |
| 1880 | |
| 1881 | |
| 1882 | /************************************************* |
| 1883 | * Initialize for SMTP incoming message * |
| 1884 | *************************************************/ |
| 1885 | |
| 1886 | /* This function conducts the initial dialogue at the start of an incoming SMTP |
| 1887 | message, and builds a list of recipients. However, if the incoming message |
| 1888 | is part of a batch (-bS option) a separate function is called since it would |
| 1889 | be messy having tests splattered about all over this function. This function |
| 1890 | therefore handles the case where interaction is occurring. The input and output |
| 1891 | files are set up in smtp_in and smtp_out. |
| 1892 | |
| 1893 | The global recipients_list is set to point to a vector of recipient_item |
| 1894 | blocks, whose number is given by recipients_count. This is extended by the |
| 1895 | receive_add_recipient() function. The global variable sender_address is set to |
| 1896 | the sender's address. The yield is +1 if a message has been successfully |
| 1897 | started, 0 if a QUIT command was encountered or the connection was refused from |
| 1898 | the particular host, or -1 if the connection was lost. |
| 1899 | |
| 1900 | Argument: none |
| 1901 | |
| 1902 | Returns: > 0 message successfully started (reached DATA) |
| 1903 | = 0 QUIT read or end of file reached or call refused |
| 1904 | < 0 lost connection |
| 1905 | */ |
| 1906 | |
| 1907 | int |
| 1908 | smtp_setup_msg(void) |
| 1909 | { |
| 1910 | int done = 0; |
| 1911 | BOOL toomany = FALSE; |
| 1912 | BOOL discarded = FALSE; |
| 1913 | BOOL last_was_rej_mail = FALSE; |
| 1914 | BOOL last_was_rcpt = FALSE; |
| 1915 | void *reset_point = store_get(0); |
| 1916 | |
| 1917 | DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n"); |
| 1918 | |
| 1919 | /* Reset for start of new message. We allow one RSET not to be counted as a |
| 1920 | nonmail command, for those MTAs that insist on sending it between every |
| 1921 | message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of |
| 1922 | TLS between messages (an Exim client may do this if it has messages queued up |
| 1923 | for the host). Note: we do NOT reset AUTH at this point. */ |
| 1924 | |
| 1925 | smtp_reset(reset_point); |
| 1926 | message_ended = END_NOTSTARTED; |
| 1927 | |
| 1928 | cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE; |
| 1929 | cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE; |
| 1930 | cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE; |
| 1931 | #ifdef SUPPORT_TLS |
| 1932 | cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE; |
| 1933 | #endif |
| 1934 | |
| 1935 | /* Set the local signal handler for SIGTERM - it tries to end off tidily */ |
| 1936 | |
| 1937 | os_non_restarting_signal(SIGTERM, command_sigterm_handler); |
| 1938 | |
| 1939 | /* Batched SMTP is handled in a different function. */ |
| 1940 | |
| 1941 | if (smtp_batched_input) return smtp_setup_batch_msg(); |
| 1942 | |
| 1943 | /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE |
| 1944 | value. The values are 2 larger than the required yield of the function. */ |
| 1945 | |
| 1946 | while (done <= 0) |
| 1947 | { |
| 1948 | uschar **argv; |
| 1949 | uschar *etrn_command; |
| 1950 | uschar *etrn_serialize_key; |
| 1951 | uschar *errmess; |
| 1952 | uschar *user_msg, *log_msg; |
| 1953 | uschar *recipient = NULL; |
| 1954 | uschar *hello = NULL; |
| 1955 | uschar *set_id = NULL; |
| 1956 | uschar *s, *ss; |
| 1957 | BOOL was_rej_mail = FALSE; |
| 1958 | BOOL was_rcpt = FALSE; |
| 1959 | void (*oldsignal)(int); |
| 1960 | pid_t pid; |
| 1961 | int start, end, sender_domain, recipient_domain; |
| 1962 | int ptr, size, rc; |
| 1963 | int c; |
| 1964 | auth_instance *au; |
| 1965 | |
| 1966 | switch(smtp_read_command(TRUE)) |
| 1967 | { |
| 1968 | /* The AUTH command is not permitted to occur inside a transaction, and may |
| 1969 | occur successfully only once per connection, and then only when we've |
| 1970 | advertised it. Actually, that isn't quite true. When TLS is started, all |
| 1971 | previous information about a connection must be discarded, so a new AUTH is |
| 1972 | permitted at that time. |
| 1973 | |
| 1974 | AUTH is initially labelled as a "nonmail command" so that one occurrence |
| 1975 | doesn't get counted. We change the label here so that multiple failing |
| 1976 | AUTHS will eventually hit the nonmail threshold. */ |
| 1977 | |
| 1978 | case AUTH_CMD: |
| 1979 | authentication_failed = TRUE; |
| 1980 | cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE; |
| 1981 | |
| 1982 | if (!auth_advertised) |
| 1983 | { |
| 1984 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 1985 | US"AUTH command used when not advertised"); |
| 1986 | break; |
| 1987 | } |
| 1988 | if (sender_host_authenticated != NULL) |
| 1989 | { |
| 1990 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 1991 | US"already authenticated"); |
| 1992 | break; |
| 1993 | } |
| 1994 | if (sender_address != NULL) |
| 1995 | { |
| 1996 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 1997 | US"not permitted in mail transaction"); |
| 1998 | break; |
| 1999 | } |
| 2000 | |
| 2001 | /* Check the ACL */ |
| 2002 | |
| 2003 | if (acl_smtp_auth != NULL) |
| 2004 | { |
| 2005 | rc = acl_check(ACL_WHERE_AUTH, smtp_data, acl_smtp_auth, &user_msg, |
| 2006 | &log_msg); |
| 2007 | if (rc != OK) |
| 2008 | { |
| 2009 | done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg); |
| 2010 | break; |
| 2011 | } |
| 2012 | } |
| 2013 | |
| 2014 | /* Find the name of the requested authentication mechanism. */ |
| 2015 | |
| 2016 | s = smtp_data; |
| 2017 | while ((c = *smtp_data) != 0 && !isspace(c)) |
| 2018 | { |
| 2019 | if (!isalnum(c) && c != '-' && c != '_') |
| 2020 | { |
| 2021 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 2022 | US"invalid character in authentication mechanism name"); |
| 2023 | goto COMMAND_LOOP; |
| 2024 | } |
| 2025 | smtp_data++; |
| 2026 | } |
| 2027 | |
| 2028 | /* If not at the end of the line, we must be at white space. Terminate the |
| 2029 | name and move the pointer on to any data that may be present. */ |
| 2030 | |
| 2031 | if (*smtp_data != 0) |
| 2032 | { |
| 2033 | *smtp_data++ = 0; |
| 2034 | while (isspace(*smtp_data)) smtp_data++; |
| 2035 | } |
| 2036 | |
| 2037 | /* Search for an authentication mechanism which is configured for use |
| 2038 | as a server and which has been advertised. */ |
| 2039 | |
| 2040 | for (au = auths; au != NULL; au = au->next) |
| 2041 | { |
| 2042 | if (strcmpic(s, au->public_name) == 0 && au->server && |
| 2043 | au->advertised) break; |
| 2044 | } |
| 2045 | |
| 2046 | if (au == NULL) |
| 2047 | { |
| 2048 | done = synprot_error(L_smtp_protocol_error, 504, NULL, |
| 2049 | string_sprintf("%s authentication mechanism not supported", s)); |
| 2050 | break; |
| 2051 | } |
| 2052 | |
| 2053 | /* Run the checking code, passing the remainder of the command |
| 2054 | line as data. Initialize $0 empty. The authenticator may set up |
| 2055 | other numeric variables. Afterwards, have a go at expanding the set_id |
| 2056 | string, even if authentication failed - for bad passwords it can be useful |
| 2057 | to log the userid. On success, require set_id to expand and exist, and |
| 2058 | put it in authenticated_id. Save this in permanent store, as the working |
| 2059 | store gets reset at HELO, RSET, etc. */ |
| 2060 | |
| 2061 | expand_nmax = 0; |
| 2062 | expand_nlength[0] = 0; /* $0 contains nothing */ |
| 2063 | |
| 2064 | c = (au->info->servercode)(au, smtp_data); |
| 2065 | if (au->set_id != NULL) set_id = expand_string(au->set_id); |
| 2066 | expand_nmax = -1; /* Reset numeric variables */ |
| 2067 | |
| 2068 | /* For the non-OK cases, set up additional logging data if set_id |
| 2069 | is not empty. */ |
| 2070 | |
| 2071 | if (c != OK) |
| 2072 | { |
| 2073 | if (set_id != NULL && *set_id != 0) |
| 2074 | set_id = string_sprintf(" (set_id=%s)", set_id); |
| 2075 | else set_id = US""; |
| 2076 | } |
| 2077 | |
| 2078 | /* Switch on the result */ |
| 2079 | |
| 2080 | switch(c) |
| 2081 | { |
| 2082 | case OK: |
| 2083 | if (au->set_id == NULL || set_id != NULL) /* Complete success */ |
| 2084 | { |
| 2085 | if (set_id != NULL) authenticated_id = string_copy_malloc(set_id); |
| 2086 | sender_host_authenticated = au->name; |
| 2087 | authentication_failed = FALSE; |
| 2088 | received_protocol = |
| 2089 | protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] + |
| 2090 | ((sender_host_address != NULL)? pnlocal : 0); |
| 2091 | s = ss = US"235 Authentication succeeded"; |
| 2092 | authenticated_by = au; |
| 2093 | break; |
| 2094 | } |
| 2095 | |
| 2096 | /* Authentication succeeded, but we failed to expand the set_id string. |
| 2097 | Treat this as a temporary error. */ |
| 2098 | |
| 2099 | auth_defer_msg = expand_string_message; |
| 2100 | /* Fall through */ |
| 2101 | |
| 2102 | case DEFER: |
| 2103 | s = string_sprintf("435 Unable to authenticate at present%s", |
| 2104 | auth_defer_user_msg); |
| 2105 | ss = string_sprintf("435 Unable to authenticate at present%s: %s", |
| 2106 | set_id, auth_defer_msg); |
| 2107 | break; |
| 2108 | |
| 2109 | case BAD64: |
| 2110 | s = ss = US"501 Invalid base64 data"; |
| 2111 | break; |
| 2112 | |
| 2113 | case CANCELLED: |
| 2114 | s = ss = US"501 Authentication cancelled"; |
| 2115 | break; |
| 2116 | |
| 2117 | case UNEXPECTED: |
| 2118 | s = ss = US"553 Initial data not expected"; |
| 2119 | break; |
| 2120 | |
| 2121 | case FAIL: |
| 2122 | s = US"535 Incorrect authentication data"; |
| 2123 | ss = string_sprintf("535 Incorrect authentication data%s", set_id); |
| 2124 | break; |
| 2125 | |
| 2126 | default: |
| 2127 | s = US"435 Internal error"; |
| 2128 | ss = string_sprintf("435 Internal error%s: return %d from authentication " |
| 2129 | "check", set_id, c); |
| 2130 | break; |
| 2131 | } |
| 2132 | |
| 2133 | smtp_printf("%s\r\n", s); |
| 2134 | if (c != OK) |
| 2135 | log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s", |
| 2136 | au->name, host_and_ident(FALSE), ss); |
| 2137 | |
| 2138 | break; /* AUTH_CMD */ |
| 2139 | |
| 2140 | /* The HELO/EHLO commands are permitted to appear in the middle of a |
| 2141 | session as well as at the beginning. They have the effect of a reset in |
| 2142 | addition to their other functions. Their absence at the start cannot be |
| 2143 | taken to be an error. |
| 2144 | |
| 2145 | RFC 2821 says: |
| 2146 | |
| 2147 | If the EHLO command is not acceptable to the SMTP server, 501, 500, |
| 2148 | or 502 failure replies MUST be returned as appropriate. The SMTP |
| 2149 | server MUST stay in the same state after transmitting these replies |
| 2150 | that it was in before the EHLO was received. |
| 2151 | |
| 2152 | Therefore, we do not do the reset until after checking the command for |
| 2153 | acceptability. This change was made for Exim release 4.11. Previously |
| 2154 | it did the reset first. */ |
| 2155 | |
| 2156 | case HELO_CMD: |
| 2157 | hello = US"HELO"; |
| 2158 | esmtp = FALSE; |
| 2159 | goto HELO_EHLO; |
| 2160 | |
| 2161 | case EHLO_CMD: |
| 2162 | hello = US"EHLO"; |
| 2163 | esmtp = TRUE; |
| 2164 | |
| 2165 | HELO_EHLO: /* Common code for HELO and EHLO */ |
| 2166 | cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE; |
| 2167 | cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE; |
| 2168 | |
| 2169 | /* Reject the HELO if its argument was invalid or non-existent. A |
| 2170 | successful check causes the argument to be saved in malloc store. */ |
| 2171 | |
| 2172 | if (!check_helo(smtp_data)) |
| 2173 | { |
| 2174 | smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello); |
| 2175 | |
| 2176 | log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically " |
| 2177 | "invalid argument(s): %s", hello, host_and_ident(FALSE), |
| 2178 | (*smtp_data == 0)? US"(no argument given)" : |
| 2179 | string_printing(smtp_data)); |
| 2180 | |
| 2181 | if (++synprot_error_count > smtp_max_synprot_errors) |
| 2182 | { |
| 2183 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " |
| 2184 | "syntax or protocol errors (last command was \"%s\")", |
| 2185 | host_and_ident(FALSE), cmd_buffer); |
| 2186 | done = 1; |
| 2187 | } |
| 2188 | |
| 2189 | break; |
| 2190 | } |
| 2191 | |
| 2192 | /* If sender_host_unknown is true, we have got here via the -bs interface, |
| 2193 | not called from inetd. Otherwise, we are running an IP connection and the |
| 2194 | host address will be set. If the helo name is the primary name of this |
| 2195 | host and we haven't done a reverse lookup, force one now. If helo_required |
| 2196 | is set, ensure that the HELO name matches the actual host. If helo_verify |
| 2197 | is set, do the same check, but softly. */ |
| 2198 | |
| 2199 | if (!sender_host_unknown) |
| 2200 | { |
| 2201 | BOOL old_helo_verified = helo_verified; |
| 2202 | uschar *p = smtp_data; |
| 2203 | |
| 2204 | while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; } |
| 2205 | *p = 0; |
| 2206 | |
| 2207 | /* Force a reverse lookup if HELO quoted something in helo_lookup_domains |
| 2208 | because otherwise the log can be confusing. */ |
| 2209 | |
| 2210 | if (sender_host_name == NULL && |
| 2211 | (deliver_domain = sender_helo_name, /* set $domain */ |
| 2212 | match_isinlist(sender_helo_name, &helo_lookup_domains, 0, |
| 2213 | &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK) |
| 2214 | (void)host_name_lookup(); |
| 2215 | |
| 2216 | /* Rebuild the fullhost info to include the HELO name (and the real name |
| 2217 | if it was looked up.) */ |
| 2218 | |
| 2219 | host_build_sender_fullhost(); /* Rebuild */ |
| 2220 | set_process_info("handling%s incoming connection from %s", |
| 2221 | (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE)); |
| 2222 | |
| 2223 | /* Verify if configured. This doesn't give much security, but it does |
| 2224 | make some people happy to be able to do it. Note that HELO is legitimately |
| 2225 | allowed to quote an address literal. Allow for IPv6 ::ffff: literals. */ |
| 2226 | |
| 2227 | helo_verified = FALSE; |
| 2228 | if (helo_required || helo_verify) |
| 2229 | { |
| 2230 | BOOL tempfail = FALSE; |
| 2231 | |
| 2232 | HDEBUG(D_receive) debug_printf("verifying %s %s\n", hello, |
| 2233 | sender_helo_name); |
| 2234 | if (sender_helo_name[0] == '[') |
| 2235 | { |
| 2236 | helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address, |
| 2237 | Ustrlen(sender_host_address)) == 0; |
| 2238 | |
| 2239 | #if HAVE_IPV6 |
| 2240 | if (!helo_verified) |
| 2241 | { |
| 2242 | if (strncmpic(sender_host_address, US"::ffff:", 7) == 0) |
| 2243 | helo_verified = Ustrncmp(sender_helo_name + 1, |
| 2244 | sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0; |
| 2245 | } |
| 2246 | #endif |
| 2247 | |
| 2248 | HDEBUG(D_receive) |
| 2249 | { if (helo_verified) debug_printf("matched host address\n"); } |
| 2250 | } |
| 2251 | |
| 2252 | /* Do a reverse lookup if one hasn't already given a positive or |
| 2253 | negative response. If that fails, or the name doesn't match, try |
| 2254 | checking with a forward lookup. */ |
| 2255 | |
| 2256 | else |
| 2257 | { |
| 2258 | if (sender_host_name == NULL && !host_lookup_failed) |
| 2259 | tempfail = host_name_lookup() == DEFER; |
| 2260 | |
| 2261 | /* If a host name is known, check it and all its aliases. */ |
| 2262 | |
| 2263 | if (sender_host_name != NULL) |
| 2264 | { |
| 2265 | helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0; |
| 2266 | |
| 2267 | if (helo_verified) |
| 2268 | { |
| 2269 | HDEBUG(D_receive) debug_printf("matched host name\n"); |
| 2270 | } |
| 2271 | else |
| 2272 | { |
| 2273 | uschar **aliases = sender_host_aliases; |
| 2274 | while (*aliases != NULL) |
| 2275 | { |
| 2276 | helo_verified = strcmpic(*aliases++, sender_helo_name) == 0; |
| 2277 | if (helo_verified) break; |
| 2278 | } |
| 2279 | HDEBUG(D_receive) |
| 2280 | { |
| 2281 | if (helo_verified) |
| 2282 | debug_printf("matched alias %s\n", *(--aliases)); |
| 2283 | } |
| 2284 | } |
| 2285 | } |
| 2286 | |
| 2287 | /* Final attempt: try a forward lookup of the helo name */ |
| 2288 | |
| 2289 | if (!helo_verified) |
| 2290 | { |
| 2291 | int rc; |
| 2292 | host_item h; |
| 2293 | h.name = sender_helo_name; |
| 2294 | h.address = NULL; |
| 2295 | h.mx = MX_NONE; |
| 2296 | h.next = NULL; |
| 2297 | HDEBUG(D_receive) debug_printf("getting IP address for %s\n", |
| 2298 | sender_helo_name); |
| 2299 | rc = host_find_byname(&h, NULL, NULL, TRUE); |
| 2300 | if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL) |
| 2301 | { |
| 2302 | host_item *hh = &h; |
| 2303 | while (hh != NULL) |
| 2304 | { |
| 2305 | if (Ustrcmp(hh->address, sender_host_address) == 0) |
| 2306 | { |
| 2307 | helo_verified = TRUE; |
| 2308 | HDEBUG(D_receive) |
| 2309 | debug_printf("IP address for %s matches calling address\n", |
| 2310 | sender_helo_name); |
| 2311 | break; |
| 2312 | } |
| 2313 | hh = hh->next; |
| 2314 | } |
| 2315 | } |
| 2316 | } |
| 2317 | } |
| 2318 | |
| 2319 | /* Verification failed. A temporary lookup failure gives a temporary |
| 2320 | error. */ |
| 2321 | |
| 2322 | if (!helo_verified) |
| 2323 | { |
| 2324 | if (helo_required) |
| 2325 | { |
| 2326 | smtp_printf("%d %s argument does not match calling host\r\n", |
| 2327 | tempfail? 451 : 550, hello); |
| 2328 | log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s", |
| 2329 | tempfail? "temporarily " : "", |
| 2330 | hello, sender_helo_name, host_and_ident(FALSE)); |
| 2331 | helo_verified = old_helo_verified; |
| 2332 | break; /* End of HELO/EHLO processing */ |
| 2333 | } |
| 2334 | HDEBUG(D_all) debug_printf("%s verification failed but host is in " |
| 2335 | "helo_try_verify_hosts\n", hello); |
| 2336 | } |
| 2337 | } |
| 2338 | } |
| 2339 | |
| 2340 | /* Apply an ACL check if one is defined */ |
| 2341 | |
| 2342 | if (acl_smtp_helo != NULL) |
| 2343 | { |
| 2344 | rc = acl_check(ACL_WHERE_HELO, smtp_data, acl_smtp_helo, &user_msg, |
| 2345 | &log_msg); |
| 2346 | if (rc != OK) |
| 2347 | { |
| 2348 | done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg); |
| 2349 | sender_helo_name = NULL; |
| 2350 | host_build_sender_fullhost(); /* Rebuild */ |
| 2351 | break; |
| 2352 | } |
| 2353 | } |
| 2354 | |
| 2355 | /* The EHLO/HELO command is acceptable. Reset the protocol and the state, |
| 2356 | abandoning any previous message. */ |
| 2357 | |
| 2358 | received_protocol = (esmtp? |
| 2359 | protocols[pextend + |
| 2360 | ((sender_host_authenticated != NULL)? pauthed : 0) + |
| 2361 | ((tls_active >= 0)? pcrpted : 0)] |
| 2362 | : |
| 2363 | protocols[pnormal]) |
| 2364 | + |
| 2365 | ((sender_host_address != NULL)? pnlocal : 0); |
| 2366 | |
| 2367 | smtp_reset(reset_point); |
| 2368 | toomany = FALSE; |
| 2369 | |
| 2370 | /* Generate an OK reply, including the ident if present, and also |
| 2371 | the IP address if present. Reflecting back the ident is intended |
| 2372 | as a deterrent to mail forgers. For maximum efficiency, and also |
| 2373 | because some broken systems expect each response to be in a single |
| 2374 | packet, arrange that it is sent in one write(). */ |
| 2375 | |
| 2376 | auth_advertised = FALSE; |
| 2377 | pipelining_advertised = FALSE; |
| 2378 | #ifdef SUPPORT_TLS |
| 2379 | tls_advertised = FALSE; |
| 2380 | #endif |
| 2381 | |
| 2382 | s = string_sprintf("250 %s Hello %s%s%s", |
| 2383 | smtp_active_hostname, |
| 2384 | (sender_ident == NULL)? US"" : sender_ident, |
| 2385 | (sender_ident == NULL)? US"" : US" at ", |
| 2386 | (sender_host_name == NULL)? sender_helo_name : sender_host_name); |
| 2387 | |
| 2388 | ptr = Ustrlen(s); |
| 2389 | size = ptr + 1; |
| 2390 | |
| 2391 | if (sender_host_address != NULL) |
| 2392 | { |
| 2393 | s = string_cat(s, &size, &ptr, US" [", 2); |
| 2394 | s = string_cat(s, &size, &ptr, sender_host_address, |
| 2395 | Ustrlen(sender_host_address)); |
| 2396 | s = string_cat(s, &size, &ptr, US"]", 1); |
| 2397 | } |
| 2398 | |
| 2399 | s = string_cat(s, &size, &ptr, US"\r\n", 2); |
| 2400 | |
| 2401 | /* If we received EHLO, we must create a multiline response which includes |
| 2402 | the functions supported. */ |
| 2403 | |
| 2404 | if (esmtp) |
| 2405 | { |
| 2406 | s[3] = '-'; |
| 2407 | |
| 2408 | /* I'm not entirely happy with this, as an MTA is supposed to check |
| 2409 | that it has enough room to accept a message of maximum size before |
| 2410 | it sends this. However, there seems little point in not sending it. |
| 2411 | The actual size check happens later at MAIL FROM time. By postponing it |
| 2412 | till then, VRFY and EXPN can be used after EHLO when space is short. */ |
| 2413 | |
| 2414 | if (thismessage_size_limit > 0) |
| 2415 | { |
| 2416 | sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit); |
| 2417 | s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer)); |
| 2418 | } |
| 2419 | else |
| 2420 | { |
| 2421 | s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10); |
| 2422 | } |
| 2423 | |
| 2424 | /* Exim does not do protocol conversion or data conversion. It is 8-bit |
| 2425 | clean; if it has an 8-bit character in its hand, it just sends it. It |
| 2426 | cannot therefore specify 8BITMIME and remain consistent with the RFCs. |
| 2427 | However, some users want this option simply in order to stop MUAs |
| 2428 | mangling messages that contain top-bit-set characters. It is therefore |
| 2429 | provided as an option. */ |
| 2430 | |
| 2431 | if (accept_8bitmime) |
| 2432 | s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14); |
| 2433 | |
| 2434 | /* Advertise ETRN if there's an ACL checking whether a host is |
| 2435 | permitted to issue it; a check is made when any host actually tries. */ |
| 2436 | |
| 2437 | if (acl_smtp_etrn != NULL) |
| 2438 | { |
| 2439 | s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10); |
| 2440 | } |
| 2441 | |
| 2442 | /* Advertise EXPN if there's an ACL checking whether a host is |
| 2443 | permitted to issue it; a check is made when any host actually tries. */ |
| 2444 | |
| 2445 | if (acl_smtp_expn != NULL) |
| 2446 | { |
| 2447 | s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10); |
| 2448 | } |
| 2449 | |
| 2450 | /* Exim is quite happy with pipelining, so let the other end know that |
| 2451 | it is safe to use it, unless advertising is disabled. */ |
| 2452 | |
| 2453 | if (verify_check_host(&pipelining_advertise_hosts) == OK) |
| 2454 | { |
| 2455 | s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16); |
| 2456 | sync_cmd_limit = NON_SYNC_CMD_PIPELINING; |
| 2457 | pipelining_advertised = TRUE; |
| 2458 | } |
| 2459 | |
| 2460 | /* If any server authentication mechanisms are configured, advertise |
| 2461 | them if the current host is in auth_advertise_hosts. The problem with |
| 2462 | advertising always is that some clients then require users to |
| 2463 | authenticate (and aren't configurable otherwise) even though it may not |
| 2464 | be necessary (e.g. if the host is in host_accept_relay). |
| 2465 | |
| 2466 | RFC 2222 states that SASL mechanism names contain only upper case |
| 2467 | letters, so output the names in upper case, though we actually recognize |
| 2468 | them in either case in the AUTH command. */ |
| 2469 | |
| 2470 | if (auths != NULL) |
| 2471 | { |
| 2472 | if (verify_check_host(&auth_advertise_hosts) == OK) |
| 2473 | { |
| 2474 | auth_instance *au; |
| 2475 | BOOL first = TRUE; |
| 2476 | for (au = auths; au != NULL; au = au->next) |
| 2477 | { |
| 2478 | if (au->server && (au->advertise_condition == NULL || |
| 2479 | expand_check_condition(au->advertise_condition, au->name, |
| 2480 | US"authenticator"))) |
| 2481 | { |
| 2482 | int saveptr; |
| 2483 | if (first) |
| 2484 | { |
| 2485 | s = string_cat(s, &size, &ptr, US"250-AUTH", 8); |
| 2486 | first = FALSE; |
| 2487 | auth_advertised = TRUE; |
| 2488 | } |
| 2489 | saveptr = ptr; |
| 2490 | s = string_cat(s, &size, &ptr, US" ", 1); |
| 2491 | s = string_cat(s, &size, &ptr, au->public_name, |
| 2492 | Ustrlen(au->public_name)); |
| 2493 | while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]); |
| 2494 | au->advertised = TRUE; |
| 2495 | } |
| 2496 | else au->advertised = FALSE; |
| 2497 | } |
| 2498 | if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2); |
| 2499 | } |
| 2500 | } |
| 2501 | |
| 2502 | /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer) |
| 2503 | if it has been included in the binary, and the host matches |
| 2504 | tls_advertise_hosts. We must *not* advertise if we are already in a |
| 2505 | secure connection. */ |
| 2506 | |
| 2507 | #ifdef SUPPORT_TLS |
| 2508 | if (tls_active < 0 && |
| 2509 | verify_check_host(&tls_advertise_hosts) != FAIL) |
| 2510 | { |
| 2511 | s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14); |
| 2512 | tls_advertised = TRUE; |
| 2513 | } |
| 2514 | #endif |
| 2515 | |
| 2516 | /* Finish off the multiline reply with one that is always available. */ |
| 2517 | |
| 2518 | s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10); |
| 2519 | } |
| 2520 | |
| 2521 | /* Terminate the string (for debug), write it, and note that HELO/EHLO |
| 2522 | has been seen. */ |
| 2523 | |
| 2524 | s[ptr] = 0; |
| 2525 | |
| 2526 | #ifdef SUPPORT_TLS |
| 2527 | if (tls_active >= 0) (void)tls_write(s, ptr); else |
| 2528 | #endif |
| 2529 | |
| 2530 | fwrite(s, 1, ptr, smtp_out); |
| 2531 | DEBUG(D_receive) debug_printf("SMTP>> %s", s); |
| 2532 | helo_seen = TRUE; |
| 2533 | break; /* HELO/EHLO */ |
| 2534 | |
| 2535 | |
| 2536 | /* The MAIL command requires an address as an operand. All we do |
| 2537 | here is to parse it for syntactic correctness. The form "<>" is |
| 2538 | a special case which converts into an empty string. The start/end |
| 2539 | pointers in the original are not used further for this address, as |
| 2540 | it is the canonical extracted address which is all that is kept. */ |
| 2541 | |
| 2542 | case MAIL_CMD: |
| 2543 | smtp_mailcmd_count++; /* Count for limit and ratelimit */ |
| 2544 | was_rej_mail = TRUE; /* Reset if accepted */ |
| 2545 | |
| 2546 | if (helo_required && !helo_seen) |
| 2547 | { |
| 2548 | smtp_printf("503 HELO or EHLO required\r\n"); |
| 2549 | log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no " |
| 2550 | "HELO/EHLO given", host_and_ident(FALSE)); |
| 2551 | break; |
| 2552 | } |
| 2553 | |
| 2554 | if (sender_address != NULL) |
| 2555 | { |
| 2556 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 2557 | US"sender already given"); |
| 2558 | break; |
| 2559 | } |
| 2560 | |
| 2561 | if (smtp_data[0] == 0) |
| 2562 | { |
| 2563 | done = synprot_error(L_smtp_protocol_error, 501, NULL, |
| 2564 | US"MAIL must have an address operand"); |
| 2565 | break; |
| 2566 | } |
| 2567 | |
| 2568 | /* Check to see if the limit for messages per connection would be |
| 2569 | exceeded by accepting further messages. */ |
| 2570 | |
| 2571 | if (smtp_accept_max_per_connection > 0 && |
| 2572 | smtp_mailcmd_count > smtp_accept_max_per_connection) |
| 2573 | { |
| 2574 | smtp_printf("421 too many messages in this connection\r\n"); |
| 2575 | log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many " |
| 2576 | "messages in one connection", host_and_ident(TRUE)); |
| 2577 | break; |
| 2578 | } |
| 2579 | |
| 2580 | /* Reset for start of message - even if this is going to fail, we |
| 2581 | obviously need to throw away any previous data. */ |
| 2582 | |
| 2583 | smtp_reset(reset_point); |
| 2584 | toomany = FALSE; |
| 2585 | sender_data = recipient_data = NULL; |
| 2586 | |
| 2587 | /* Loop, checking for ESMTP additions to the MAIL FROM command. */ |
| 2588 | |
| 2589 | if (esmtp) for(;;) |
| 2590 | { |
| 2591 | uschar *name, *value, *end; |
| 2592 | unsigned long int size; |
| 2593 | |
| 2594 | if (!extract_option(&name, &value)) break; |
| 2595 | |
| 2596 | /* Handle SIZE= by reading the value. We don't do the check till later, |
| 2597 | in order to be able to log the sender address on failure. */ |
| 2598 | |
| 2599 | if (strcmpic(name, US"SIZE") == 0 && |
| 2600 | ((size = (int)Ustrtoul(value, &end, 10)), *end == 0)) |
| 2601 | { |
| 2602 | if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX) |
| 2603 | size = INT_MAX; |
| 2604 | message_size = (int)size; |
| 2605 | } |
| 2606 | |
| 2607 | /* If this session was initiated with EHLO and accept_8bitmime is set, |
| 2608 | Exim will have indicated that it supports the BODY=8BITMIME option. In |
| 2609 | fact, it does not support this according to the RFCs, in that it does not |
| 2610 | take any special action for forwarding messages containing 8-bit |
| 2611 | characters. That is why accept_8bitmime is not the default setting, but |
| 2612 | some sites want the action that is provided. We recognize both "8BITMIME" |
| 2613 | and "7BIT" as body types, but take no action. */ |
| 2614 | |
| 2615 | else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 && |
| 2616 | (strcmpic(value, US"8BITMIME") == 0 || |
| 2617 | strcmpic(value, US"7BIT") == 0)) {} |
| 2618 | |
| 2619 | /* Handle the AUTH extension. If the value given is not "<>" and either |
| 2620 | the ACL says "yes" or there is no ACL but the sending host is |
| 2621 | authenticated, we set it up as the authenticated sender. However, if the |
| 2622 | authenticator set a condition to be tested, we ignore AUTH on MAIL unless |
| 2623 | the condition is met. The value of AUTH is an xtext, which means that +, |
| 2624 | = and cntrl chars are coded in hex; however "<>" is unaffected by this |
| 2625 | coding. */ |
| 2626 | |
| 2627 | else if (strcmpic(name, US"AUTH") == 0) |
| 2628 | { |
| 2629 | if (Ustrcmp(value, "<>") != 0) |
| 2630 | { |
| 2631 | int rc; |
| 2632 | uschar *ignore_msg; |
| 2633 | |
| 2634 | if (auth_xtextdecode(value, &authenticated_sender) < 0) |
| 2635 | { |
| 2636 | /* Put back terminator overrides for error message */ |
| 2637 | name[-1] = ' '; |
| 2638 | value[-1] = '='; |
| 2639 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 2640 | US"invalid data for AUTH"); |
| 2641 | goto COMMAND_LOOP; |
| 2642 | } |
| 2643 | |
| 2644 | if (acl_smtp_mailauth == NULL) |
| 2645 | { |
| 2646 | ignore_msg = US"client not authenticated"; |
| 2647 | rc = (sender_host_authenticated != NULL)? OK : FAIL; |
| 2648 | } |
| 2649 | else |
| 2650 | { |
| 2651 | ignore_msg = US"rejected by ACL"; |
| 2652 | rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth, |
| 2653 | &user_msg, &log_msg); |
| 2654 | } |
| 2655 | |
| 2656 | switch (rc) |
| 2657 | { |
| 2658 | case OK: |
| 2659 | if (authenticated_by == NULL || |
| 2660 | authenticated_by->mail_auth_condition == NULL || |
| 2661 | expand_check_condition(authenticated_by->mail_auth_condition, |
| 2662 | authenticated_by->name, US"authenticator")) |
| 2663 | break; /* Accept the AUTH */ |
| 2664 | |
| 2665 | ignore_msg = US"server_mail_auth_condition failed"; |
| 2666 | if (authenticated_id != NULL) |
| 2667 | ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"", |
| 2668 | ignore_msg, authenticated_id); |
| 2669 | |
| 2670 | /* Fall through */ |
| 2671 | |
| 2672 | case FAIL: |
| 2673 | authenticated_sender = NULL; |
| 2674 | log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)", |
| 2675 | value, host_and_ident(TRUE), ignore_msg); |
| 2676 | break; |
| 2677 | |
| 2678 | /* Should only get DEFER or ERROR here. Put back terminator |
| 2679 | overrides for error message */ |
| 2680 | |
| 2681 | default: |
| 2682 | name[-1] = ' '; |
| 2683 | value[-1] = '='; |
| 2684 | (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg, |
| 2685 | log_msg); |
| 2686 | goto COMMAND_LOOP; |
| 2687 | } |
| 2688 | } |
| 2689 | } |
| 2690 | |
| 2691 | /* Unknown option. Stick back the terminator characters and break |
| 2692 | the loop. An error for a malformed address will occur. */ |
| 2693 | |
| 2694 | else |
| 2695 | { |
| 2696 | name[-1] = ' '; |
| 2697 | value[-1] = '='; |
| 2698 | break; |
| 2699 | } |
| 2700 | } |
| 2701 | |
| 2702 | /* If we have passed the threshold for rate limiting, apply the current |
| 2703 | delay, and update it for next time, provided this is a limited host. */ |
| 2704 | |
| 2705 | if (smtp_mailcmd_count > smtp_rlm_threshold && |
| 2706 | verify_check_host(&smtp_ratelimit_hosts) == OK) |
| 2707 | { |
| 2708 | DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n", |
| 2709 | smtp_delay_mail/1000.0); |
| 2710 | millisleep((int)smtp_delay_mail); |
| 2711 | smtp_delay_mail *= smtp_rlm_factor; |
| 2712 | if (smtp_delay_mail > (double)smtp_rlm_limit) |
| 2713 | smtp_delay_mail = (double)smtp_rlm_limit; |
| 2714 | } |
| 2715 | |
| 2716 | /* Now extract the address, first applying any SMTP-time rewriting. The |
| 2717 | TRUE flag allows "<>" as a sender address. */ |
| 2718 | |
| 2719 | raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)? |
| 2720 | rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"", |
| 2721 | global_rewrite_rules) : smtp_data; |
| 2722 | |
| 2723 | /* rfc821_domains = TRUE; << no longer needed */ |
| 2724 | raw_sender = |
| 2725 | parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain, |
| 2726 | TRUE); |
| 2727 | /* rfc821_domains = FALSE; << no longer needed */ |
| 2728 | |
| 2729 | if (raw_sender == NULL) |
| 2730 | { |
| 2731 | done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess); |
| 2732 | break; |
| 2733 | } |
| 2734 | |
| 2735 | sender_address = raw_sender; |
| 2736 | |
| 2737 | /* If there is a configured size limit for mail, check that this message |
| 2738 | doesn't exceed it. The check is postponed to this point so that the sender |
| 2739 | can be logged. */ |
| 2740 | |
| 2741 | if (thismessage_size_limit > 0 && message_size > thismessage_size_limit) |
| 2742 | { |
| 2743 | smtp_printf("552 Message size exceeds maximum permitted\r\n"); |
| 2744 | log_write(L_size_reject, |
| 2745 | LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: " |
| 2746 | "message too big: size%s=%d max=%d", |
| 2747 | sender_address, |
| 2748 | host_and_ident(TRUE), |
| 2749 | (message_size == INT_MAX)? ">" : "", |
| 2750 | message_size, |
| 2751 | thismessage_size_limit); |
| 2752 | sender_address = NULL; |
| 2753 | break; |
| 2754 | } |
| 2755 | |
| 2756 | /* Check there is enough space on the disk unless configured not to. |
| 2757 | When smtp_check_spool_space is set, the check is for thismessage_size_limit |
| 2758 | plus the current message - i.e. we accept the message only if it won't |
| 2759 | reduce the space below the threshold. Add 5000 to the size to allow for |
| 2760 | overheads such as the Received: line and storing of recipients, etc. |
| 2761 | By putting the check here, even when SIZE is not given, it allow VRFY |
| 2762 | and EXPN etc. to be used when space is short. */ |
| 2763 | |
| 2764 | if (!receive_check_fs( |
| 2765 | (smtp_check_spool_space && message_size >= 0)? |
| 2766 | message_size + 5000 : 0)) |
| 2767 | { |
| 2768 | smtp_printf("452 Space shortage, please try later\r\n"); |
| 2769 | sender_address = NULL; |
| 2770 | break; |
| 2771 | } |
| 2772 | |
| 2773 | /* If sender_address is unqualified, reject it, unless this is a locally |
| 2774 | generated message, or the sending host or net is permitted to send |
| 2775 | unqualified addresses - typically local machines behaving as MUAs - |
| 2776 | in which case just qualify the address. The flag is set above at the start |
| 2777 | of the SMTP connection. */ |
| 2778 | |
| 2779 | if (sender_domain == 0 && sender_address[0] != 0) |
| 2780 | { |
| 2781 | if (allow_unqualified_sender) |
| 2782 | { |
| 2783 | sender_domain = Ustrlen(sender_address) + 1; |
| 2784 | sender_address = rewrite_address_qualify(sender_address, FALSE); |
| 2785 | DEBUG(D_receive) debug_printf("unqualified address %s accepted\n", |
| 2786 | raw_sender); |
| 2787 | } |
| 2788 | else |
| 2789 | { |
| 2790 | smtp_printf("501 %s: sender address must contain a domain\r\n", |
| 2791 | smtp_data); |
| 2792 | log_write(L_smtp_syntax_error, |
| 2793 | LOG_MAIN|LOG_REJECT, |
| 2794 | "unqualified sender rejected: <%s> %s%s", |
| 2795 | raw_sender, |
| 2796 | host_and_ident(TRUE), |
| 2797 | host_lookup_msg); |
| 2798 | sender_address = NULL; |
| 2799 | break; |
| 2800 | } |
| 2801 | } |
| 2802 | |
| 2803 | /* Apply an ACL check if one is defined, before responding */ |
| 2804 | |
| 2805 | rc = (acl_smtp_mail == NULL)? OK : |
| 2806 | acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg); |
| 2807 | |
| 2808 | if (rc == OK || rc == DISCARD) |
| 2809 | { |
| 2810 | smtp_printf("250 OK\r\n"); |
| 2811 | smtp_delay_rcpt = smtp_rlr_base; |
| 2812 | recipients_discarded = (rc == DISCARD); |
| 2813 | was_rej_mail = FALSE; |
| 2814 | } |
| 2815 | |
| 2816 | else |
| 2817 | { |
| 2818 | done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg); |
| 2819 | sender_address = NULL; |
| 2820 | } |
| 2821 | break; |
| 2822 | |
| 2823 | |
| 2824 | /* The RCPT command requires an address as an operand. All we do |
| 2825 | here is to parse it for syntactic correctness. There may be any number |
| 2826 | of RCPT commands, specifying multiple senders. We build them all into |
| 2827 | a data structure that is in argc/argv format. The start/end values |
| 2828 | given by parse_extract_address are not used, as we keep only the |
| 2829 | extracted address. */ |
| 2830 | |
| 2831 | case RCPT_CMD: |
| 2832 | rcpt_count++; |
| 2833 | was_rcpt = TRUE; |
| 2834 | |
| 2835 | /* There must be a sender address; if the sender was rejected and |
| 2836 | pipelining was advertised, we assume the client was pipelining, and do not |
| 2837 | count this as a protocol error. Reset was_rej_mail so that further RCPTs |
| 2838 | get the same treatment. */ |
| 2839 | |
| 2840 | if (sender_address == NULL) |
| 2841 | { |
| 2842 | if (pipelining_advertised && last_was_rej_mail) |
| 2843 | { |
| 2844 | smtp_printf("503 sender not yet given\r\n"); |
| 2845 | was_rej_mail = TRUE; |
| 2846 | } |
| 2847 | else |
| 2848 | { |
| 2849 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 2850 | US"sender not yet given"); |
| 2851 | was_rcpt = FALSE; /* Not a valid RCPT */ |
| 2852 | } |
| 2853 | rcpt_fail_count++; |
| 2854 | break; |
| 2855 | } |
| 2856 | |
| 2857 | /* Check for an operand */ |
| 2858 | |
| 2859 | if (smtp_data[0] == 0) |
| 2860 | { |
| 2861 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 2862 | US"RCPT must have an address operand"); |
| 2863 | rcpt_fail_count++; |
| 2864 | break; |
| 2865 | } |
| 2866 | |
| 2867 | /* Apply SMTP rewriting then extract the working address. Don't allow "<>" |
| 2868 | as a recipient address */ |
| 2869 | |
| 2870 | recipient = ((rewrite_existflags & rewrite_smtp) != 0)? |
| 2871 | rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"", |
| 2872 | global_rewrite_rules) : smtp_data; |
| 2873 | |
| 2874 | /* rfc821_domains = TRUE; << no longer needed */ |
| 2875 | recipient = parse_extract_address(recipient, &errmess, &start, &end, |
| 2876 | &recipient_domain, FALSE); |
| 2877 | /* rfc821_domains = FALSE; << no longer needed */ |
| 2878 | |
| 2879 | if (recipient == NULL) |
| 2880 | { |
| 2881 | done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess); |
| 2882 | rcpt_fail_count++; |
| 2883 | break; |
| 2884 | } |
| 2885 | |
| 2886 | /* If the recipient address is unqualified, reject it, unless this is a |
| 2887 | locally generated message. However, unqualified addresses are permitted |
| 2888 | from a configured list of hosts and nets - typically when behaving as |
| 2889 | MUAs rather than MTAs. Sad that SMTP is used for both types of traffic, |
| 2890 | really. The flag is set at the start of the SMTP connection. |
| 2891 | |
| 2892 | RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always |
| 2893 | assumed this meant "reserved local part", but the revision of RFC 821 and |
| 2894 | friends now makes it absolutely clear that it means *mailbox*. Consequently |
| 2895 | we must always qualify this address, regardless. */ |
| 2896 | |
| 2897 | if (recipient_domain == 0) |
| 2898 | { |
| 2899 | if (allow_unqualified_recipient || |
| 2900 | strcmpic(recipient, US"postmaster") == 0) |
| 2901 | { |
| 2902 | DEBUG(D_receive) debug_printf("unqualified address %s accepted\n", |
| 2903 | recipient); |
| 2904 | recipient_domain = Ustrlen(recipient) + 1; |
| 2905 | recipient = rewrite_address_qualify(recipient, TRUE); |
| 2906 | } |
| 2907 | else |
| 2908 | { |
| 2909 | rcpt_fail_count++; |
| 2910 | smtp_printf("501 %s: recipient address must contain a domain\r\n", |
| 2911 | smtp_data); |
| 2912 | log_write(L_smtp_syntax_error, |
| 2913 | LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: " |
| 2914 | "<%s> %s%s", recipient, host_and_ident(TRUE), |
| 2915 | host_lookup_msg); |
| 2916 | break; |
| 2917 | } |
| 2918 | } |
| 2919 | |
| 2920 | /* Check maximum allowed */ |
| 2921 | |
| 2922 | if (rcpt_count > recipients_max && recipients_max > 0) |
| 2923 | { |
| 2924 | if (recipients_max_reject) |
| 2925 | { |
| 2926 | rcpt_fail_count++; |
| 2927 | smtp_printf("552 too many recipients\r\n"); |
| 2928 | if (!toomany) |
| 2929 | log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message " |
| 2930 | "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE)); |
| 2931 | } |
| 2932 | else |
| 2933 | { |
| 2934 | rcpt_defer_count++; |
| 2935 | smtp_printf("452 too many recipients\r\n"); |
| 2936 | if (!toomany) |
| 2937 | log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess " |
| 2938 | "temporarily rejected: sender=<%s> %s", sender_address, |
| 2939 | host_and_ident(TRUE)); |
| 2940 | } |
| 2941 | |
| 2942 | toomany = TRUE; |
| 2943 | break; |
| 2944 | } |
| 2945 | |
| 2946 | /* If we have passed the threshold for rate limiting, apply the current |
| 2947 | delay, and update it for next time, provided this is a limited host. */ |
| 2948 | |
| 2949 | if (rcpt_count > smtp_rlr_threshold && |
| 2950 | verify_check_host(&smtp_ratelimit_hosts) == OK) |
| 2951 | { |
| 2952 | DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n", |
| 2953 | smtp_delay_rcpt/1000.0); |
| 2954 | millisleep((int)smtp_delay_rcpt); |
| 2955 | smtp_delay_rcpt *= smtp_rlr_factor; |
| 2956 | if (smtp_delay_rcpt > (double)smtp_rlr_limit) |
| 2957 | smtp_delay_rcpt = (double)smtp_rlr_limit; |
| 2958 | } |
| 2959 | |
| 2960 | /* If the MAIL ACL discarded all the recipients, we bypass ACL checking |
| 2961 | for them. Otherwise, check the access control list for this recipient. */ |
| 2962 | |
| 2963 | rc = recipients_discarded? DISCARD : |
| 2964 | acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg); |
| 2965 | |
| 2966 | /* The ACL was happy */ |
| 2967 | |
| 2968 | if (rc == OK) |
| 2969 | { |
| 2970 | smtp_printf("250 Accepted\r\n"); |
| 2971 | receive_add_recipient(recipient, -1); |
| 2972 | } |
| 2973 | |
| 2974 | /* The recipient was discarded */ |
| 2975 | |
| 2976 | else if (rc == DISCARD) |
| 2977 | { |
| 2978 | smtp_printf("250 Accepted\r\n"); |
| 2979 | rcpt_fail_count++; |
| 2980 | discarded = TRUE; |
| 2981 | log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: " |
| 2982 | "discarded by %s ACL%s%s", host_and_ident(TRUE), |
| 2983 | (sender_address_unrewritten != NULL)? |
| 2984 | sender_address_unrewritten : sender_address, |
| 2985 | smtp_data, recipients_discarded? "MAIL" : "RCPT", |
| 2986 | (log_msg == NULL)? US"" : US": ", |
| 2987 | (log_msg == NULL)? US"" : log_msg); |
| 2988 | } |
| 2989 | |
| 2990 | /* Either the ACL failed the address, or it was deferred. */ |
| 2991 | |
| 2992 | else |
| 2993 | { |
| 2994 | if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++; |
| 2995 | done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg); |
| 2996 | } |
| 2997 | break; |
| 2998 | |
| 2999 | |
| 3000 | /* The DATA command is legal only if it follows successful MAIL FROM |
| 3001 | and RCPT TO commands. However, if pipelining is advertised, a bad DATA is |
| 3002 | not counted as a protocol error if it follows RCPT (which must have been |
| 3003 | rejected if there are no recipients.) This function is complete when a |
| 3004 | valid DATA command is encountered. |
| 3005 | |
| 3006 | Note concerning the code used: RFC 2821 says this: |
| 3007 | |
| 3008 | - If there was no MAIL, or no RCPT, command, or all such commands |
| 3009 | were rejected, the server MAY return a "command out of sequence" |
| 3010 | (503) or "no valid recipients" (554) reply in response to the |
| 3011 | DATA command. |
| 3012 | |
| 3013 | The example in the pipelining RFC 2920 uses 554, but I use 503 here |
| 3014 | because it is the same whether pipelining is in use or not. */ |
| 3015 | |
| 3016 | case DATA_CMD: |
| 3017 | if (!discarded && recipients_count <= 0) |
| 3018 | { |
| 3019 | if (pipelining_advertised && last_was_rcpt) |
| 3020 | smtp_printf("503 valid RCPT command must precede DATA\r\n"); |
| 3021 | else |
| 3022 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 3023 | US"valid RCPT command must precede DATA"); |
| 3024 | break; |
| 3025 | } |
| 3026 | |
| 3027 | if (toomany && recipients_max_reject) |
| 3028 | { |
| 3029 | sender_address = NULL; /* This will allow a new MAIL without RSET */ |
| 3030 | sender_address_unrewritten = NULL; |
| 3031 | smtp_printf("554 Too many recipients\r\n"); |
| 3032 | break; |
| 3033 | } |
| 3034 | |
| 3035 | rc = (acl_smtp_predata == NULL)? OK : |
| 3036 | acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg, &log_msg); |
| 3037 | |
| 3038 | if (rc == OK) |
| 3039 | { |
| 3040 | smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n"); |
| 3041 | done = 3; |
| 3042 | message_ended = END_NOTENDED; /* Indicate in middle of data */ |
| 3043 | } |
| 3044 | |
| 3045 | /* Either the ACL failed the address, or it was deferred. */ |
| 3046 | |
| 3047 | else |
| 3048 | done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg); |
| 3049 | |
| 3050 | break; |
| 3051 | |
| 3052 | |
| 3053 | case VRFY_CMD: |
| 3054 | rc = acl_check(ACL_WHERE_VRFY, smtp_data, acl_smtp_vrfy, &user_msg, |
| 3055 | &log_msg); |
| 3056 | if (rc != OK) |
| 3057 | done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg); |
| 3058 | else |
| 3059 | { |
| 3060 | uschar *address; |
| 3061 | uschar *s = NULL; |
| 3062 | |
| 3063 | /* rfc821_domains = TRUE; << no longer needed */ |
| 3064 | address = parse_extract_address(smtp_data, &errmess, &start, &end, |
| 3065 | &recipient_domain, FALSE); |
| 3066 | /* rfc821_domains = FALSE; << no longer needed */ |
| 3067 | |
| 3068 | if (address == NULL) |
| 3069 | s = string_sprintf("501 %s", errmess); |
| 3070 | else |
| 3071 | { |
| 3072 | address_item *addr = deliver_make_addr(address, FALSE); |
| 3073 | switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1, |
| 3074 | -1, NULL, NULL, NULL)) |
| 3075 | { |
| 3076 | case OK: |
| 3077 | s = string_sprintf("250 <%s> is deliverable", address); |
| 3078 | break; |
| 3079 | |
| 3080 | case DEFER: |
| 3081 | s = (addr->message != NULL)? |
| 3082 | string_sprintf("451 <%s> %s", address, addr->message) : |
| 3083 | string_sprintf("451 Cannot resolve <%s> at this time", address); |
| 3084 | break; |
| 3085 | |
| 3086 | case FAIL: |
| 3087 | s = (addr->message != NULL)? |
| 3088 | string_sprintf("550 <%s> %s", address, addr->message) : |
| 3089 | string_sprintf("550 <%s> is not deliverable", address); |
| 3090 | log_write(0, LOG_MAIN, "VRFY failed for %s %s", |
| 3091 | smtp_data, host_and_ident(TRUE)); |
| 3092 | break; |
| 3093 | } |
| 3094 | } |
| 3095 | |
| 3096 | smtp_printf("%s\r\n", s); |
| 3097 | } |
| 3098 | break; |
| 3099 | |
| 3100 | |
| 3101 | case EXPN_CMD: |
| 3102 | rc = acl_check(ACL_WHERE_EXPN, smtp_data, acl_smtp_expn, &user_msg, |
| 3103 | &log_msg); |
| 3104 | if (rc != OK) |
| 3105 | done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg); |
| 3106 | else |
| 3107 | { |
| 3108 | BOOL save_log_testing_mode = log_testing_mode; |
| 3109 | address_test_mode = log_testing_mode = TRUE; |
| 3110 | (void) verify_address(deliver_make_addr(smtp_data, FALSE), smtp_out, |
| 3111 | vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, NULL, NULL, NULL); |
| 3112 | address_test_mode = FALSE; |
| 3113 | log_testing_mode = save_log_testing_mode; /* true for -bh */ |
| 3114 | } |
| 3115 | break; |
| 3116 | |
| 3117 | |
| 3118 | #ifdef SUPPORT_TLS |
| 3119 | |
| 3120 | case STARTTLS_CMD: |
| 3121 | if (!tls_advertised) |
| 3122 | { |
| 3123 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 3124 | US"STARTTLS command used when not advertised"); |
| 3125 | break; |
| 3126 | } |
| 3127 | |
| 3128 | /* Apply an ACL check if one is defined */ |
| 3129 | |
| 3130 | if (acl_smtp_starttls != NULL) |
| 3131 | { |
| 3132 | rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg, |
| 3133 | &log_msg); |
| 3134 | if (rc != OK) |
| 3135 | { |
| 3136 | done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg); |
| 3137 | break; |
| 3138 | } |
| 3139 | } |
| 3140 | |
| 3141 | /* RFC 2487 is not clear on when this command may be sent, though it |
| 3142 | does state that all information previously obtained from the client |
| 3143 | must be discarded if a TLS session is started. It seems reasonble to |
| 3144 | do an implied RSET when STARTTLS is received. */ |
| 3145 | |
| 3146 | incomplete_transaction_log(US"STARTTLS"); |
| 3147 | smtp_reset(reset_point); |
| 3148 | toomany = FALSE; |
| 3149 | cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE; |
| 3150 | |
| 3151 | /* Attempt to start up a TLS session, and if successful, discard all |
| 3152 | knowledge that was obtained previously. At least, that's what the RFC says, |
| 3153 | and that's what happens by default. However, in order to work round YAEB, |
| 3154 | there is an option to remember the esmtp state. Sigh. |
| 3155 | |
| 3156 | We must allow for an extra EHLO command and an extra AUTH command after |
| 3157 | STARTTLS that don't add to the nonmail command count. */ |
| 3158 | |
| 3159 | if ((rc = tls_server_start(tls_require_ciphers)) == OK) |
| 3160 | { |
| 3161 | if (!tls_remember_esmtp) |
| 3162 | helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE; |
| 3163 | cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE; |
| 3164 | cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE; |
| 3165 | if (sender_helo_name != NULL) |
| 3166 | { |
| 3167 | store_free(sender_helo_name); |
| 3168 | sender_helo_name = NULL; |
| 3169 | host_build_sender_fullhost(); /* Rebuild */ |
| 3170 | set_process_info("handling incoming TLS connection from %s", |
| 3171 | host_and_ident(FALSE)); |
| 3172 | } |
| 3173 | received_protocol = (esmtp? |
| 3174 | protocols[pextend + pcrpted + |
| 3175 | ((sender_host_authenticated != NULL)? pauthed : 0)] |
| 3176 | : |
| 3177 | protocols[pnormal]) |
| 3178 | + |
| 3179 | ((sender_host_address != NULL)? pnlocal : 0); |
| 3180 | |
| 3181 | sender_host_authenticated = NULL; |
| 3182 | authenticated_id = NULL; |
| 3183 | sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING; |
| 3184 | DEBUG(D_tls) debug_printf("TLS active\n"); |
| 3185 | break; /* Successful STARTTLS */ |
| 3186 | } |
| 3187 | |
| 3188 | /* Some local configuration problem was discovered before actually trying |
| 3189 | to do a TLS handshake; give a temporary error. */ |
| 3190 | |
| 3191 | else if (rc == DEFER) |
| 3192 | { |
| 3193 | smtp_printf("454 TLS currently unavailable\r\n"); |
| 3194 | break; |
| 3195 | } |
| 3196 | |
| 3197 | /* Hard failure. Reject everything except QUIT or closed connection. One |
| 3198 | cause for failure is a nested STARTTLS, in which case tls_active remains |
| 3199 | set, but we must still reject all incoming commands. */ |
| 3200 | |
| 3201 | DEBUG(D_tls) debug_printf("TLS failed to start\n"); |
| 3202 | while (done <= 0) |
| 3203 | { |
| 3204 | switch(smtp_read_command(FALSE)) |
| 3205 | { |
| 3206 | case EOF_CMD: |
| 3207 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF", |
| 3208 | smtp_get_connection_info()); |
| 3209 | done = 2; |
| 3210 | break; |
| 3211 | |
| 3212 | case QUIT_CMD: |
| 3213 | smtp_printf("221 %s closing connection\r\n", smtp_active_hostname); |
| 3214 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT", |
| 3215 | smtp_get_connection_info()); |
| 3216 | done = 2; |
| 3217 | break; |
| 3218 | |
| 3219 | default: |
| 3220 | smtp_printf("554 Security failure\r\n"); |
| 3221 | break; |
| 3222 | } |
| 3223 | } |
| 3224 | tls_close(TRUE); |
| 3225 | break; |
| 3226 | #endif |
| 3227 | |
| 3228 | |
| 3229 | /* The ACL for QUIT is provided for gathering statistical information or |
| 3230 | similar; it does not affect the response code, but it can supply a custom |
| 3231 | message. */ |
| 3232 | |
| 3233 | case QUIT_CMD: |
| 3234 | incomplete_transaction_log(US"QUIT"); |
| 3235 | |
| 3236 | if (acl_smtp_quit != NULL) |
| 3237 | { |
| 3238 | rc = acl_check(ACL_WHERE_QUIT, US"", acl_smtp_quit,&user_msg,&log_msg); |
| 3239 | if (rc == ERROR) |
| 3240 | log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s", |
| 3241 | log_msg); |
| 3242 | } |
| 3243 | else user_msg = NULL; |
| 3244 | |
| 3245 | if (user_msg == NULL) |
| 3246 | smtp_printf("221 %s closing connection\r\n", smtp_active_hostname); |
| 3247 | else |
| 3248 | smtp_printf("221 %s\r\n", user_msg); |
| 3249 | |
| 3250 | #ifdef SUPPORT_TLS |
| 3251 | tls_close(TRUE); |
| 3252 | #endif |
| 3253 | |
| 3254 | done = 2; |
| 3255 | log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT", |
| 3256 | smtp_get_connection_info()); |
| 3257 | break; |
| 3258 | |
| 3259 | |
| 3260 | case RSET_CMD: |
| 3261 | incomplete_transaction_log(US"RSET"); |
| 3262 | smtp_reset(reset_point); |
| 3263 | toomany = FALSE; |
| 3264 | smtp_printf("250 Reset OK\r\n"); |
| 3265 | cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE; |
| 3266 | break; |
| 3267 | |
| 3268 | |
| 3269 | case NOOP_CMD: |
| 3270 | smtp_printf("250 OK\r\n"); |
| 3271 | break; |
| 3272 | |
| 3273 | |
| 3274 | /* Show ETRN/EXPN/VRFY if there's |
| 3275 | an ACL for checking hosts; if actually used, a check will be done for |
| 3276 | permitted hosts. */ |
| 3277 | |
| 3278 | case HELP_CMD: |
| 3279 | smtp_printf("214-Commands supported:\r\n"); |
| 3280 | { |
| 3281 | uschar buffer[256]; |
| 3282 | buffer[0] = 0; |
| 3283 | Ustrcat(buffer, " AUTH"); |
| 3284 | #ifdef SUPPORT_TLS |
| 3285 | Ustrcat(buffer, " STARTTLS"); |
| 3286 | #endif |
| 3287 | Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA"); |
| 3288 | Ustrcat(buffer, " NOOP QUIT RSET HELP"); |
| 3289 | if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN"); |
| 3290 | if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN"); |
| 3291 | if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY"); |
| 3292 | smtp_printf("214%s\r\n", buffer); |
| 3293 | } |
| 3294 | break; |
| 3295 | |
| 3296 | |
| 3297 | case EOF_CMD: |
| 3298 | incomplete_transaction_log(US"connection lost"); |
| 3299 | smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname); |
| 3300 | |
| 3301 | /* Don't log by default unless in the middle of a message, as some mailers |
| 3302 | just drop the call rather than sending QUIT, and it clutters up the logs. |
| 3303 | */ |
| 3304 | |
| 3305 | if (sender_address != NULL || recipients_count > 0) |
| 3306 | log_write(L_lost_incoming_connection, |
| 3307 | LOG_MAIN, |
| 3308 | "unexpected %s while reading SMTP command from %s%s", |
| 3309 | sender_host_unknown? "EOF" : "disconnection", |
| 3310 | host_and_ident(FALSE), smtp_read_error); |
| 3311 | |
| 3312 | else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s", |
| 3313 | smtp_get_connection_info(), smtp_read_error); |
| 3314 | |
| 3315 | done = 1; |
| 3316 | break; |
| 3317 | |
| 3318 | |
| 3319 | case ETRN_CMD: |
| 3320 | if (sender_address != NULL) |
| 3321 | { |
| 3322 | done = synprot_error(L_smtp_protocol_error, 503, NULL, |
| 3323 | US"ETRN is not permitted inside a transaction"); |
| 3324 | break; |
| 3325 | } |
| 3326 | |
| 3327 | log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_data, |
| 3328 | host_and_ident(FALSE)); |
| 3329 | |
| 3330 | rc = acl_check(ACL_WHERE_ETRN, smtp_data, acl_smtp_etrn, &user_msg, |
| 3331 | &log_msg); |
| 3332 | if (rc != OK) |
| 3333 | { |
| 3334 | done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg); |
| 3335 | break; |
| 3336 | } |
| 3337 | |
| 3338 | /* Compute the serialization key for this command. */ |
| 3339 | |
| 3340 | etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_data); |
| 3341 | |
| 3342 | /* If a command has been specified for running as a result of ETRN, we |
| 3343 | permit any argument to ETRN. If not, only the # standard form is permitted, |
| 3344 | since that is strictly the only kind of ETRN that can be implemented |
| 3345 | according to the RFC. */ |
| 3346 | |
| 3347 | if (smtp_etrn_command != NULL) |
| 3348 | { |
| 3349 | uschar *error; |
| 3350 | BOOL rc; |
| 3351 | etrn_command = smtp_etrn_command; |
| 3352 | deliver_domain = smtp_data; |
| 3353 | rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL, |
| 3354 | US"ETRN processing", &error); |
| 3355 | deliver_domain = NULL; |
| 3356 | if (!rc) |
| 3357 | { |
| 3358 | log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s", |
| 3359 | error); |
| 3360 | smtp_printf("458 Internal failure\r\n"); |
| 3361 | break; |
| 3362 | } |
| 3363 | } |
| 3364 | |
| 3365 | /* Else set up to call Exim with the -R option. */ |
| 3366 | |
| 3367 | else |
| 3368 | { |
| 3369 | if (*smtp_data++ != '#') |
| 3370 | { |
| 3371 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 3372 | US"argument must begin with #"); |
| 3373 | break; |
| 3374 | } |
| 3375 | etrn_command = US"exim -R"; |
| 3376 | argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R", |
| 3377 | smtp_data); |
| 3378 | } |
| 3379 | |
| 3380 | /* If we are host-testing, don't actually do anything. */ |
| 3381 | |
| 3382 | if (host_checking) |
| 3383 | { |
| 3384 | HDEBUG(D_any) |
| 3385 | { |
| 3386 | debug_printf("ETRN command is: %s\n", etrn_command); |
| 3387 | debug_printf("ETRN command execution skipped\n"); |
| 3388 | } |
| 3389 | smtp_printf("250 OK\r\n"); |
| 3390 | break; |
| 3391 | } |
| 3392 | |
| 3393 | |
| 3394 | /* If ETRN queue runs are to be serialized, check the database to |
| 3395 | ensure one isn't already running. */ |
| 3396 | |
| 3397 | if (smtp_etrn_serialize && !enq_start(etrn_serialize_key)) |
| 3398 | { |
| 3399 | smtp_printf("458 Already processing %s\r\n", smtp_data); |
| 3400 | break; |
| 3401 | } |
| 3402 | |
| 3403 | /* Fork a child process and run the command. We don't want to have to |
| 3404 | wait for the process at any point, so set SIGCHLD to SIG_IGN before |
| 3405 | forking. It should be set that way anyway for external incoming SMTP, |
| 3406 | but we save and restore to be tidy. If serialization is required, we |
| 3407 | actually run the command in yet another process, so we can wait for it |
| 3408 | to complete and then remove the serialization lock. */ |
| 3409 | |
| 3410 | oldsignal = signal(SIGCHLD, SIG_IGN); |
| 3411 | |
| 3412 | if ((pid = fork()) == 0) |
| 3413 | { |
| 3414 | smtp_input = FALSE; /* This process is not associated with the */ |
| 3415 | fclose(smtp_in); /* SMTP call any more. */ |
| 3416 | fclose(smtp_out); |
| 3417 | |
| 3418 | signal(SIGCHLD, SIG_DFL); /* Want to catch child */ |
| 3419 | |
| 3420 | /* If not serializing, do the exec right away. Otherwise, fork down |
| 3421 | into another process. */ |
| 3422 | |
| 3423 | if (!smtp_etrn_serialize || (pid = fork()) == 0) |
| 3424 | { |
| 3425 | DEBUG(D_exec) debug_print_argv(argv); |
| 3426 | exim_nullstd(); /* Ensure std{in,out,err} exist */ |
| 3427 | execv(CS argv[0], (char *const *)argv); |
| 3428 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s", |
| 3429 | etrn_command, strerror(errno)); |
| 3430 | _exit(EXIT_FAILURE); /* paranoia */ |
| 3431 | } |
| 3432 | |
| 3433 | /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That |
| 3434 | is, we are in the first subprocess, after forking again. All we can do |
| 3435 | for a failing fork is to log it. Otherwise, wait for the 2nd process to |
| 3436 | complete, before removing the serialization. */ |
| 3437 | |
| 3438 | if (pid < 0) |
| 3439 | log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN " |
| 3440 | "failed: %s", strerror(errno)); |
| 3441 | else |
| 3442 | { |
| 3443 | int status; |
| 3444 | DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n", |
| 3445 | (int)pid); |
| 3446 | (void)wait(&status); |
| 3447 | DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n", |
| 3448 | (int)pid); |
| 3449 | } |
| 3450 | |
| 3451 | enq_end(etrn_serialize_key); |
| 3452 | _exit(EXIT_SUCCESS); |
| 3453 | } |
| 3454 | |
| 3455 | /* Back in the top level SMTP process. Check that we started a subprocess |
| 3456 | and restore the signal state. */ |
| 3457 | |
| 3458 | if (pid < 0) |
| 3459 | { |
| 3460 | log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s", |
| 3461 | strerror(errno)); |
| 3462 | smtp_printf("458 Unable to fork process\r\n"); |
| 3463 | if (smtp_etrn_serialize) enq_end(etrn_serialize_key); |
| 3464 | } |
| 3465 | else smtp_printf("250 OK\r\n"); |
| 3466 | |
| 3467 | signal(SIGCHLD, oldsignal); |
| 3468 | break; |
| 3469 | |
| 3470 | |
| 3471 | case BADARG_CMD: |
| 3472 | done = synprot_error(L_smtp_syntax_error, 501, NULL, |
| 3473 | US"unexpected argument data"); |
| 3474 | break; |
| 3475 | |
| 3476 | |
| 3477 | /* This currently happens only for NULLs, but could be extended. */ |
| 3478 | |
| 3479 | case BADCHAR_CMD: |
| 3480 | done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */ |
| 3481 | US"NULL character(s) present (shown as '?')"); |
| 3482 | smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n"); |
| 3483 | break; |
| 3484 | |
| 3485 | |
| 3486 | case BADSYN_CMD: |
| 3487 | if (smtp_inend >= smtp_inbuffer + in_buffer_size) |
| 3488 | smtp_inend = smtp_inbuffer + in_buffer_size - 1; |
| 3489 | c = smtp_inend - smtp_inptr; |
| 3490 | if (c > 150) c = 150; |
| 3491 | smtp_inptr[c] = 0; |
| 3492 | incomplete_transaction_log(US"sync failure"); |
| 3493 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: " |
| 3494 | "synchronization error " |
| 3495 | "(next input sent too soon: pipelining was%s advertised): " |
| 3496 | "rejected \"%s\" %s next input=\"%s\"", |
| 3497 | pipelining_advertised? "" : " not", |
| 3498 | cmd_buffer, host_and_ident(TRUE), |
| 3499 | string_printing(smtp_inptr)); |
| 3500 | smtp_printf("554 SMTP synchronization error\r\n"); |
| 3501 | done = 1; /* Pretend eof - drops connection */ |
| 3502 | break; |
| 3503 | |
| 3504 | |
| 3505 | case TOO_MANY_NONMAIL_CMD: |
| 3506 | incomplete_transaction_log(US"too many non-mail commands"); |
| 3507 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " |
| 3508 | "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE), |
| 3509 | smtp_data - cmd_buffer, cmd_buffer); |
| 3510 | smtp_printf("554 Too many nonmail commands\r\n"); |
| 3511 | done = 1; /* Pretend eof - drops connection */ |
| 3512 | break; |
| 3513 | |
| 3514 | |
| 3515 | default: |
| 3516 | if (unknown_command_count++ >= smtp_max_unknown_commands) |
| 3517 | { |
| 3518 | log_write(L_smtp_syntax_error, LOG_MAIN, |
| 3519 | "SMTP syntax error in \"%s\" %s %s", |
| 3520 | string_printing(cmd_buffer), host_and_ident(TRUE), |
| 3521 | US"unrecognized command"); |
| 3522 | incomplete_transaction_log(US"unrecognized command"); |
| 3523 | smtp_printf("500 Too many unrecognized commands\r\n"); |
| 3524 | done = 2; |
| 3525 | log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " |
| 3526 | "unrecognized commands (last was \"%s\")", host_and_ident(FALSE), |
| 3527 | cmd_buffer); |
| 3528 | } |
| 3529 | else |
| 3530 | done = synprot_error(L_smtp_syntax_error, 500, NULL, |
| 3531 | US"unrecognized command"); |
| 3532 | break; |
| 3533 | } |
| 3534 | |
| 3535 | /* This label is used by goto's inside loops that want to break out to |
| 3536 | the end of the command-processing loop. */ |
| 3537 | |
| 3538 | COMMAND_LOOP: |
| 3539 | last_was_rej_mail = was_rej_mail; /* Remember some last commands for */ |
| 3540 | last_was_rcpt = was_rcpt; /* protocol error handling */ |
| 3541 | continue; |
| 3542 | } |
| 3543 | |
| 3544 | return done - 2; /* Convert yield values */ |
| 3545 | } |
| 3546 | |
| 3547 | /* End of smtp_in.c */ |