Do not advertise STARTTLS in response to HELP unless it would be
[exim.git] / src / src / smtp_in.c
1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.58 2007/04/16 11:17:13 ph10 Exp $ */
2
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
6
7 /* Copyright (c) University of Cambridge 1995 - 2007 */
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. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. */
41
42 #define smtp_cmd_buffer_size 2048
43
44 /* Size of buffer for reading SMTP incoming packets */
45
46 #define in_buffer_size 8192
47
48 /* Structure for SMTP command list */
49
50 typedef struct {
51 char *name;
52 int len;
53 short int cmd;
54 short int has_arg;
55 short int is_mail_cmd;
56 } smtp_cmd_list;
57
58 /* Codes for identifying commands. We order them so that those that come first
59 are those for which synchronization is always required. Checking this can help
60 block some spam. */
61
62 enum {
63 /* These commands are required to be synchronized, i.e. to be the last in a
64 block of commands when pipelining. */
65
66 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
67 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
68 ETRN_CMD, /* This by analogy with TURN from the RFC */
69 STARTTLS_CMD, /* Required by the STARTTLS RFC */
70
71 /* This is a dummy to identify the non-sync commands when pipelining */
72
73 NON_SYNC_CMD_PIPELINING,
74
75 /* These commands need not be synchronized when pipelining */
76
77 MAIL_CMD, RCPT_CMD, RSET_CMD,
78
79 /* This is a dummy to identify the non-sync commands when not pipelining */
80
81 NON_SYNC_CMD_NON_PIPELINING,
82
83 /* I have been unable to find a statement about the use of pipelining
84 with AUTH, so to be on the safe side it is here, though I kind of feel
85 it should be up there with the synchronized commands. */
86
87 AUTH_CMD,
88
89 /* I'm not sure about these, but I don't think they matter. */
90
91 QUIT_CMD, HELP_CMD,
92
93 /* These are specials that don't correspond to actual commands */
94
95 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
96 TOO_MANY_NONMAIL_CMD };
97
98
99 /* This is a convenience macro for adding the identity of an SMTP command
100 to the circular buffer that holds a list of the last n received. */
101
102 #define HAD(n) \
103 smtp_connection_had[smtp_ch_index++] = n; \
104 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
105
106
107 /*************************************************
108 * Local static variables *
109 *************************************************/
110
111 static auth_instance *authenticated_by;
112 static BOOL auth_advertised;
113 #ifdef SUPPORT_TLS
114 static BOOL tls_advertised;
115 #endif
116 static BOOL esmtp;
117 static BOOL helo_required = FALSE;
118 static BOOL helo_verify = FALSE;
119 static BOOL helo_seen;
120 static BOOL helo_accept_junk;
121 static BOOL count_nonmail;
122 static BOOL pipelining_advertised;
123 static BOOL rcpt_smtp_response_same;
124 static BOOL rcpt_in_progress;
125 static int nonmail_command_count;
126 static int synprot_error_count;
127 static int unknown_command_count;
128 static int sync_cmd_limit;
129 static int smtp_write_error = 0;
130
131 static uschar *rcpt_smtp_response;
132 static uschar *smtp_data_buffer;
133 static uschar *smtp_cmd_data;
134
135 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
136 final fields of all except AUTH are forced TRUE at the start of a new message
137 setup, to allow one of each between messages that is not counted as a nonmail
138 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
139 allow a new EHLO after starting up TLS.
140
141 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
142 counted. However, the flag is changed when AUTH is received, so that multiple
143 failing AUTHs will eventually hit the limit. After a successful AUTH, another
144 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
145 forced TRUE, to allow for the re-authentication that can happen at that point.
146
147 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
148 count of non-mail commands and possibly provoke an error. */
149
150 static smtp_cmd_list cmd_list[] = {
151 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
152 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
153 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
154 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
155 #ifdef SUPPORT_TLS
156 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
157 #endif
158
159 /* If you change anything above here, also fix the definitions below. */
160
161 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
162 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
163 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
164 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
165 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
166 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
167 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
168 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
169 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
170 };
171
172 static smtp_cmd_list *cmd_list_end =
173 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
174
175 #define CMD_LIST_RSET 0
176 #define CMD_LIST_HELO 1
177 #define CMD_LIST_EHLO 2
178 #define CMD_LIST_AUTH 3
179 #define CMD_LIST_STARTTLS 4
180
181 /* This list of names is used for performing the smtp_no_mail logging action.
182 It must be kept in step with the SCH_xxx enumerations. */
183
184 static uschar *smtp_names[] =
185 {
186 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
187 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
188 US"VRFY" };
189
190 static uschar *protocols[] = {
191 US"local-smtp", /* HELO */
192 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
193 US"local-esmtp", /* EHLO */
194 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
195 US"local-esmtpa", /* EHLO->AUTH */
196 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
197 };
198
199 #define pnormal 0
200 #define pextend 2
201 #define pcrpted 1 /* added to pextend or pnormal */
202 #define pauthed 2 /* added to pextend */
203 #define pnlocal 6 /* offset to remove "local" */
204
205 /* When reading SMTP from a remote host, we have to use our own versions of the
206 C input-reading functions, in order to be able to flush the SMTP output only
207 when about to read more data from the socket. This is the only way to get
208 optimal performance when the client is using pipelining. Flushing for every
209 command causes a separate packet and reply packet each time; saving all the
210 responses up (when pipelining) combines them into one packet and one response.
211
212 For simplicity, these functions are used for *all* SMTP input, not only when
213 receiving over a socket. However, after setting up a secure socket (SSL), input
214 is read via the OpenSSL library, and another set of functions is used instead
215 (see tls.c).
216
217 These functions are set in the receive_getc etc. variables and called with the
218 same interface as the C functions. However, since there can only ever be
219 one incoming SMTP call, we just use a single buffer and flags. There is no need
220 to implement a complicated private FILE-like structure.*/
221
222 static uschar *smtp_inbuffer;
223 static uschar *smtp_inptr;
224 static uschar *smtp_inend;
225 static int smtp_had_eof;
226 static int smtp_had_error;
227
228
229 /*************************************************
230 * SMTP version of getc() *
231 *************************************************/
232
233 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
234 it flushes the output, and refills the buffer, with a timeout. The signal
235 handler is set appropriately by the calling function. This function is not used
236 after a connection has negotated itself into an TLS/SSL state.
237
238 Arguments: none
239 Returns: the next character or EOF
240 */
241
242 int
243 smtp_getc(void)
244 {
245 if (smtp_inptr >= smtp_inend)
246 {
247 int rc, save_errno;
248 fflush(smtp_out);
249 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
250 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
251 save_errno = errno;
252 alarm(0);
253 if (rc <= 0)
254 {
255 /* Must put the error text in fixed store, because this might be during
256 header reading, where it releases unused store above the header. */
257 if (rc < 0)
258 {
259 smtp_had_error = save_errno;
260 smtp_read_error = string_copy_malloc(
261 string_sprintf(" (error: %s)", strerror(save_errno)));
262 }
263 else smtp_had_eof = 1;
264 return EOF;
265 }
266 smtp_inend = smtp_inbuffer + rc;
267 smtp_inptr = smtp_inbuffer;
268 }
269 return *smtp_inptr++;
270 }
271
272
273
274 /*************************************************
275 * SMTP version of ungetc() *
276 *************************************************/
277
278 /* Puts a character back in the input buffer. Only ever
279 called once.
280
281 Arguments:
282 ch the character
283
284 Returns: the character
285 */
286
287 int
288 smtp_ungetc(int ch)
289 {
290 *(--smtp_inptr) = ch;
291 return ch;
292 }
293
294
295
296
297 /*************************************************
298 * SMTP version of feof() *
299 *************************************************/
300
301 /* Tests for a previous EOF
302
303 Arguments: none
304 Returns: non-zero if the eof flag is set
305 */
306
307 int
308 smtp_feof(void)
309 {
310 return smtp_had_eof;
311 }
312
313
314
315
316 /*************************************************
317 * SMTP version of ferror() *
318 *************************************************/
319
320 /* Tests for a previous read error, and returns with errno
321 restored to what it was when the error was detected.
322
323 Arguments: none
324 Returns: non-zero if the error flag is set
325 */
326
327 int
328 smtp_ferror(void)
329 {
330 errno = smtp_had_error;
331 return smtp_had_error;
332 }
333
334
335
336 /*************************************************
337 * Test for characters in the SMTP buffer *
338 *************************************************/
339
340 /* Used at the end of a message
341
342 Arguments: none
343 Returns: TRUE/FALSE
344 */
345
346 BOOL
347 smtp_buffered(void)
348 {
349 return smtp_inptr < smtp_inend;
350 }
351
352
353
354 /*************************************************
355 * Write formatted string to SMTP channel *
356 *************************************************/
357
358 /* This is a separate function so that we don't have to repeat everything for
359 TLS support or debugging. It is global so that the daemon and the
360 authentication functions can use it. It does not return any error indication,
361 because major problems such as dropped connections won't show up till an output
362 flush for non-TLS connections. The smtp_fflush() function is available for
363 checking that: for convenience, TLS output errors are remembered here so that
364 they are also picked up later by smtp_fflush().
365
366 Arguments:
367 format format string
368 ... optional arguments
369
370 Returns: nothing
371 */
372
373 void
374 smtp_printf(char *format, ...)
375 {
376 va_list ap;
377
378 DEBUG(D_receive)
379 {
380 uschar *cr, *end;
381 va_start(ap, format);
382 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
383 va_end(ap);
384 end = big_buffer + Ustrlen(big_buffer);
385 while ((cr = Ustrchr(big_buffer, '\r')) != NULL) /* lose CRs */
386 memmove(cr, cr + 1, (end--) - cr);
387 debug_printf("SMTP>> %s", big_buffer);
388 }
389
390 va_start(ap, format);
391 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
392 {
393 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
394 smtp_closedown(US"Unexpected error");
395 exim_exit(EXIT_FAILURE);
396 }
397 va_end(ap);
398
399 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
400 have had the same. Note: this code is also present in smtp_respond(). It would
401 be tidier to have it only in one place, but when it was added, it was easier to
402 do it that way, so as not to have to mess with the code for the RCPT command,
403 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
404
405 if (rcpt_in_progress)
406 {
407 if (rcpt_smtp_response == NULL)
408 rcpt_smtp_response = string_copy(big_buffer);
409 else if (rcpt_smtp_response_same &&
410 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
411 rcpt_smtp_response_same = FALSE;
412 rcpt_in_progress = FALSE;
413 }
414
415 /* Now write the string */
416
417 #ifdef SUPPORT_TLS
418 if (tls_active >= 0)
419 {
420 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
421 }
422 else
423 #endif
424
425 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
426 }
427
428
429
430 /*************************************************
431 * Flush SMTP out and check for error *
432 *************************************************/
433
434 /* This function isn't currently used within Exim (it detects errors when it
435 tries to read the next SMTP input), but is available for use in local_scan().
436 For non-TLS connections, it flushes the output and checks for errors. For
437 TLS-connections, it checks for a previously-detected TLS write error.
438
439 Arguments: none
440 Returns: 0 for no error; -1 after an error
441 */
442
443 int
444 smtp_fflush(void)
445 {
446 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
447 return smtp_write_error;
448 }
449
450
451
452 /*************************************************
453 * SMTP command read timeout *
454 *************************************************/
455
456 /* Signal handler for timing out incoming SMTP commands. This attempts to
457 finish off tidily.
458
459 Argument: signal number (SIGALRM)
460 Returns: nothing
461 */
462
463 static void
464 command_timeout_handler(int sig)
465 {
466 sig = sig; /* Keep picky compilers happy */
467 log_write(L_lost_incoming_connection,
468 LOG_MAIN, "SMTP command timeout on%s connection from %s",
469 (tls_active >= 0)? " TLS" : "",
470 host_and_ident(FALSE));
471 if (smtp_batched_input)
472 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
473 smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
474 smtp_active_hostname);
475 mac_smtp_fflush();
476 exim_exit(EXIT_FAILURE);
477 }
478
479
480
481 /*************************************************
482 * SIGTERM received *
483 *************************************************/
484
485 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
486
487 Argument: signal number (SIGTERM)
488 Returns: nothing
489 */
490
491 static void
492 command_sigterm_handler(int sig)
493 {
494 sig = sig; /* Keep picky compilers happy */
495 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
496 if (smtp_batched_input)
497 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
498 smtp_printf("421 %s: Service not available - closing connection\r\n",
499 smtp_active_hostname);
500 exim_exit(EXIT_FAILURE);
501 }
502
503
504
505
506 /*************************************************
507 * Read one command line *
508 *************************************************/
509
510 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
511 There are sites that don't do this, and in any case internal SMTP probably
512 should check only for LF. Consequently, we check here for LF only. The line
513 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
514 an unknown command. The command is read into the global smtp_cmd_buffer so that
515 it is available via $smtp_command.
516
517 The character reading routine sets up a timeout for each block actually read
518 from the input (which may contain more than one command). We set up a special
519 signal handler that closes down the session on a timeout. Control does not
520 return when it runs.
521
522 Arguments:
523 check_sync if TRUE, check synchronization rules if global option is TRUE
524
525 Returns: a code identifying the command (enumerated above)
526 */
527
528 static int
529 smtp_read_command(BOOL check_sync)
530 {
531 int c;
532 int ptr = 0;
533 smtp_cmd_list *p;
534 BOOL hadnull = FALSE;
535
536 os_non_restarting_signal(SIGALRM, command_timeout_handler);
537
538 while ((c = (receive_getc)()) != '\n' && c != EOF)
539 {
540 if (ptr >= smtp_cmd_buffer_size)
541 {
542 os_non_restarting_signal(SIGALRM, sigalrm_handler);
543 return OTHER_CMD;
544 }
545 if (c == 0)
546 {
547 hadnull = TRUE;
548 c = '?';
549 }
550 smtp_cmd_buffer[ptr++] = c;
551 }
552
553 receive_linecount++; /* For BSMTP errors */
554 os_non_restarting_signal(SIGALRM, sigalrm_handler);
555
556 /* If hit end of file, return pseudo EOF command. Whether we have a
557 part-line already read doesn't matter, since this is an error state. */
558
559 if (c == EOF) return EOF_CMD;
560
561 /* Remove any CR and white space at the end of the line, and terminate the
562 string. */
563
564 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
565 smtp_cmd_buffer[ptr] = 0;
566
567 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
568
569 /* NULLs are not allowed in SMTP commands */
570
571 if (hadnull) return BADCHAR_CMD;
572
573 /* Scan command list and return identity, having set the data pointer
574 to the start of the actual data characters. Check for SMTP synchronization
575 if required. */
576
577 for (p = cmd_list; p < cmd_list_end; p++)
578 {
579 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
580 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
581 smtp_cmd_buffer[p->len] == 0 ||
582 smtp_cmd_buffer[p->len] == ' '))
583 {
584 if (smtp_inptr < smtp_inend && /* Outstanding input */
585 p->cmd < sync_cmd_limit && /* Command should sync */
586 check_sync && /* Local flag set */
587 smtp_enforce_sync && /* Global flag set */
588 sender_host_address != NULL && /* Not local input */
589 !sender_host_notsocket) /* Really is a socket */
590 return BADSYN_CMD;
591
592 /* The variables $smtp_command and $smtp_command_argument point into the
593 unmodified input buffer. A copy of the latter is taken for actual
594 processing, so that it can be chopped up into separate parts if necessary,
595 for example, when processing a MAIL command options such as SIZE that can
596 follow the sender address. */
597
598 smtp_cmd_argument = smtp_cmd_buffer + p->len;
599 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
600 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
601 smtp_cmd_data = smtp_data_buffer;
602
603 /* Count non-mail commands from those hosts that are controlled in this
604 way. The default is all hosts. We don't waste effort checking the list
605 until we get a non-mail command, but then cache the result to save checking
606 again. If there's a DEFER while checking the host, assume it's in the list.
607
608 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
609 start of each incoming message by fiddling with the value in the table. */
610
611 if (!p->is_mail_cmd)
612 {
613 if (count_nonmail == TRUE_UNSET) count_nonmail =
614 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
615 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
616 return TOO_MANY_NONMAIL_CMD;
617 }
618
619 /* If there is data for a command that does not expect it, generate the
620 error here. */
621
622 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
623 }
624 }
625
626 /* Enforce synchronization for unknown commands */
627
628 if (smtp_inptr < smtp_inend && /* Outstanding input */
629 check_sync && /* Local flag set */
630 smtp_enforce_sync && /* Global flag set */
631 sender_host_address != NULL && /* Not local input */
632 !sender_host_notsocket) /* Really is a socket */
633 return BADSYN_CMD;
634
635 return OTHER_CMD;
636 }
637
638
639
640 /*************************************************
641 * Recheck synchronization *
642 *************************************************/
643
644 /* Synchronization checks can never be perfect because a packet may be on its
645 way but not arrived when the check is done. Such checks can in any case only be
646 done when TLS is not in use. Normally, the checks happen when commands are
647 read: Exim ensures that there is no more input in the input buffer. In normal
648 cases, the response to the command will be fast, and there is no further check.
649
650 However, for some commands an ACL is run, and that can include delays. In those
651 cases, it is useful to do another check on the input just before sending the
652 response. This also applies at the start of a connection. This function does
653 that check by means of the select() function, as long as the facility is not
654 disabled or inappropriate. A failure of select() is ignored.
655
656 When there is unwanted input, we read it so that it appears in the log of the
657 error.
658
659 Arguments: none
660 Returns: TRUE if all is well; FALSE if there is input pending
661 */
662
663 static BOOL
664 check_sync(void)
665 {
666 int fd, rc;
667 fd_set fds;
668 struct timeval tzero;
669
670 if (!smtp_enforce_sync || sender_host_address == NULL ||
671 sender_host_notsocket || tls_active >= 0)
672 return TRUE;
673
674 fd = fileno(smtp_in);
675 FD_ZERO(&fds);
676 FD_SET(fd, &fds);
677 tzero.tv_sec = 0;
678 tzero.tv_usec = 0;
679 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
680
681 if (rc <= 0) return TRUE; /* Not ready to read */
682 rc = smtp_getc();
683 if (rc < 0) return TRUE; /* End of file or error */
684
685 smtp_ungetc(rc);
686 rc = smtp_inend - smtp_inptr;
687 if (rc > 150) rc = 150;
688 smtp_inptr[rc] = 0;
689 return FALSE;
690 }
691
692
693
694 /*************************************************
695 * Forced closedown of call *
696 *************************************************/
697
698 /* This function is called from log.c when Exim is dying because of a serious
699 disaster, and also from some other places. If an incoming non-batched SMTP
700 channel is open, it swallows the rest of the incoming message if in the DATA
701 phase, sends the reply string, and gives an error to all subsequent commands
702 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
703 smtp_in.
704
705 Argument: SMTP reply string to send, excluding the code
706 Returns: nothing
707 */
708
709 void
710 smtp_closedown(uschar *message)
711 {
712 if (smtp_in == NULL || smtp_batched_input) return;
713 receive_swallow_smtp();
714 smtp_printf("421 %s\r\n", message);
715
716 for (;;)
717 {
718 switch(smtp_read_command(FALSE))
719 {
720 case EOF_CMD:
721 return;
722
723 case QUIT_CMD:
724 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
725 mac_smtp_fflush();
726 return;
727
728 case RSET_CMD:
729 smtp_printf("250 Reset OK\r\n");
730 break;
731
732 default:
733 smtp_printf("421 %s\r\n", message);
734 break;
735 }
736 }
737 }
738
739
740
741
742 /*************************************************
743 * Set up connection info for logging *
744 *************************************************/
745
746 /* This function is called when logging information about an SMTP connection.
747 It sets up appropriate source information, depending on the type of connection.
748 If sender_fullhost is NULL, we are at a very early stage of the connection;
749 just use the IP address.
750
751 Argument: none
752 Returns: a string describing the connection
753 */
754
755 uschar *
756 smtp_get_connection_info(void)
757 {
758 uschar *hostname = (sender_fullhost == NULL)?
759 sender_host_address : sender_fullhost;
760
761 if (host_checking)
762 return string_sprintf("SMTP connection from %s", hostname);
763
764 if (sender_host_unknown || sender_host_notsocket)
765 return string_sprintf("SMTP connection from %s", sender_ident);
766
767 if (is_inetd)
768 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
769
770 if ((log_extra_selector & LX_incoming_interface) != 0 &&
771 interface_address != NULL)
772 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
773 interface_address, interface_port);
774
775 return string_sprintf("SMTP connection from %s", hostname);
776 }
777
778
779
780 /*************************************************
781 * Log lack of MAIL if so configured *
782 *************************************************/
783
784 /* This function is called when an SMTP session ends. If the log selector
785 smtp_no_mail is set, write a log line giving some details of what has happened
786 in the SMTP session.
787
788 Arguments: none
789 Returns: nothing
790 */
791
792 void
793 smtp_log_no_mail(void)
794 {
795 int size, ptr, i;
796 uschar *s, *sep;
797
798 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
799 return;
800
801 s = NULL;
802 size = ptr = 0;
803
804 if (sender_host_authenticated != NULL)
805 {
806 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
807 if (authenticated_id != NULL)
808 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
809 }
810
811 #ifdef SUPPORT_TLS
812 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_cipher != NULL)
813 s = string_append(s, &size, &ptr, 2, US" X=", tls_cipher);
814 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
815 tls_cipher != NULL)
816 s = string_append(s, &size, &ptr, 2, US" CV=",
817 tls_certificate_verified? "yes":"no");
818 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_peerdn != NULL)
819 s = string_append(s, &size, &ptr, 3, US" DN=\"", tls_peerdn, US"\"");
820 #endif
821
822 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
823 US" C=..." : US" C=";
824 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
825 {
826 if (smtp_connection_had[i] != SCH_NONE)
827 {
828 s = string_append(s, &size, &ptr, 2, sep,
829 smtp_names[smtp_connection_had[i]]);
830 sep = US",";
831 }
832 }
833
834 for (i = 0; i < smtp_ch_index; i++)
835 {
836 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
837 sep = US",";
838 }
839
840 if (s != NULL) s[ptr] = 0; else s = US"";
841 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
842 host_and_ident(FALSE),
843 readconf_printtime(time(NULL) - smtp_connection_start), s);
844 }
845
846
847
848 /*************************************************
849 * Check HELO line and set sender_helo_name *
850 *************************************************/
851
852 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
853 the domain name of the sending host, or an ip literal in square brackets. The
854 arrgument is placed in sender_helo_name, which is in malloc store, because it
855 must persist over multiple incoming messages. If helo_accept_junk is set, this
856 host is permitted to send any old junk (needed for some broken hosts).
857 Otherwise, helo_allow_chars can be used for rogue characters in general
858 (typically people want to let in underscores).
859
860 Argument:
861 s the data portion of the line (already past any white space)
862
863 Returns: TRUE or FALSE
864 */
865
866 static BOOL
867 check_helo(uschar *s)
868 {
869 uschar *start = s;
870 uschar *end = s + Ustrlen(s);
871 BOOL yield = helo_accept_junk;
872
873 /* Discard any previous helo name */
874
875 if (sender_helo_name != NULL)
876 {
877 store_free(sender_helo_name);
878 sender_helo_name = NULL;
879 }
880
881 /* Skip tests if junk is permitted. */
882
883 if (!yield)
884 {
885 /* Allow the new standard form for IPv6 address literals, namely,
886 [IPv6:....], and because someone is bound to use it, allow an equivalent
887 IPv4 form. Allow plain addresses as well. */
888
889 if (*s == '[')
890 {
891 if (end[-1] == ']')
892 {
893 end[-1] = 0;
894 if (strncmpic(s, US"[IPv6:", 6) == 0)
895 yield = (string_is_ip_address(s+6, NULL) == 6);
896 else if (strncmpic(s, US"[IPv4:", 6) == 0)
897 yield = (string_is_ip_address(s+6, NULL) == 4);
898 else
899 yield = (string_is_ip_address(s+1, NULL) != 0);
900 end[-1] = ']';
901 }
902 }
903
904 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
905 that have been configured (usually underscore - sigh). */
906
907 else if (*s != 0)
908 {
909 yield = TRUE;
910 while (*s != 0)
911 {
912 if (!isalnum(*s) && *s != '.' && *s != '-' &&
913 Ustrchr(helo_allow_chars, *s) == NULL)
914 {
915 yield = FALSE;
916 break;
917 }
918 s++;
919 }
920 }
921 }
922
923 /* Save argument if OK */
924
925 if (yield) sender_helo_name = string_copy_malloc(start);
926 return yield;
927 }
928
929
930
931
932
933 /*************************************************
934 * Extract SMTP command option *
935 *************************************************/
936
937 /* This function picks the next option setting off the end of smtp_cmd_data. It
938 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
939 things that can appear there.
940
941 Arguments:
942 name point this at the name
943 value point this at the data string
944
945 Returns: TRUE if found an option
946 */
947
948 static BOOL
949 extract_option(uschar **name, uschar **value)
950 {
951 uschar *n;
952 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
953 while (isspace(*v)) v--;
954 v[1] = 0;
955
956 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
957 if (*v != '=') return FALSE;
958
959 n = v;
960 while(isalpha(n[-1])) n--;
961
962 if (n[-1] != ' ') return FALSE;
963
964 n[-1] = 0;
965 *name = n;
966 *v++ = 0;
967 *value = v;
968 return TRUE;
969 }
970
971
972
973
974
975 /*************************************************
976 * Reset for new message *
977 *************************************************/
978
979 /* This function is called whenever the SMTP session is reset from
980 within either of the setup functions.
981
982 Argument: the stacking pool storage reset point
983 Returns: nothing
984 */
985
986 static void
987 smtp_reset(void *reset_point)
988 {
989 store_reset(reset_point);
990 recipients_list = NULL;
991 rcpt_count = rcpt_defer_count = rcpt_fail_count =
992 raw_recipients_count = recipients_count = recipients_list_max = 0;
993 message_linecount = 0;
994 message_size = -1;
995 acl_added_headers = NULL;
996 queue_only_policy = FALSE;
997 rcpt_smtp_response = NULL;
998 rcpt_smtp_response_same = TRUE;
999 rcpt_in_progress = FALSE;
1000 deliver_freeze = FALSE; /* Can be set by ACL */
1001 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1002 fake_response = OK; /* Can be set by ACL */
1003 #ifdef WITH_CONTENT_SCAN
1004 no_mbox_unspool = FALSE; /* Can be set by ACL */
1005 #endif
1006 submission_mode = FALSE; /* Can be set by ACL */
1007 suppress_local_fixups = FALSE; /* Can be set by ACL */
1008 active_local_from_check = local_from_check; /* Can be set by ACL */
1009 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1010 sender_address = NULL;
1011 submission_name = NULL; /* Can be set by ACL */
1012 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1013 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1014 sender_verified_list = NULL; /* No senders verified */
1015 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1016 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1017 authenticated_sender = NULL;
1018 #ifdef EXPERIMENTAL_BRIGHTMAIL
1019 bmi_run = 0;
1020 bmi_verdicts = NULL;
1021 #endif
1022 #ifdef EXPERIMENTAL_DOMAINKEYS
1023 dk_do_verify = 0;
1024 #endif
1025 #ifdef EXPERIMENTAL_SPF
1026 spf_header_comment = NULL;
1027 spf_received = NULL;
1028 spf_result = NULL;
1029 spf_smtp_comment = NULL;
1030 #endif
1031 body_linecount = body_zerocount = 0;
1032
1033 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1034 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1035 /* Note that ratelimiters_conn persists across resets. */
1036
1037 /* Reset message ACL variables */
1038
1039 acl_var_m = NULL;
1040
1041 /* The message body variables use malloc store. They may be set if this is
1042 not the first message in an SMTP session and the previous message caused them
1043 to be referenced in an ACL. */
1044
1045 if (message_body != NULL)
1046 {
1047 store_free(message_body);
1048 message_body = NULL;
1049 }
1050
1051 if (message_body_end != NULL)
1052 {
1053 store_free(message_body_end);
1054 message_body_end = NULL;
1055 }
1056
1057 /* Warning log messages are also saved in malloc store. They are saved to avoid
1058 repetition in the same message, but it seems right to repeat them for different
1059 messages. */
1060
1061 while (acl_warn_logged != NULL)
1062 {
1063 string_item *this = acl_warn_logged;
1064 acl_warn_logged = acl_warn_logged->next;
1065 store_free(this);
1066 }
1067 }
1068
1069
1070
1071
1072
1073 /*************************************************
1074 * Initialize for incoming batched SMTP message *
1075 *************************************************/
1076
1077 /* This function is called from smtp_setup_msg() in the case when
1078 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1079 of messages in one file with SMTP commands between them. All errors must be
1080 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1081 relevant. After an error on a sender, or an invalid recipient, the remainder
1082 of the message is skipped. The value of received_protocol is already set.
1083
1084 Argument: none
1085 Returns: > 0 message successfully started (reached DATA)
1086 = 0 QUIT read or end of file reached
1087 < 0 should not occur
1088 */
1089
1090 static int
1091 smtp_setup_batch_msg(void)
1092 {
1093 int done = 0;
1094 void *reset_point = store_get(0);
1095
1096 /* Save the line count at the start of each transaction - single commands
1097 like HELO and RSET count as whole transactions. */
1098
1099 bsmtp_transaction_linecount = receive_linecount;
1100
1101 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1102
1103 smtp_reset(reset_point); /* Reset for start of message */
1104
1105 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1106 value. The values are 2 larger than the required yield of the function. */
1107
1108 while (done <= 0)
1109 {
1110 uschar *errmess;
1111 uschar *recipient = NULL;
1112 int start, end, sender_domain, recipient_domain;
1113
1114 switch(smtp_read_command(FALSE))
1115 {
1116 /* The HELO/EHLO commands set sender_address_helo if they have
1117 valid data; otherwise they are ignored, except that they do
1118 a reset of the state. */
1119
1120 case HELO_CMD:
1121 case EHLO_CMD:
1122
1123 check_helo(smtp_cmd_data);
1124 /* Fall through */
1125
1126 case RSET_CMD:
1127 smtp_reset(reset_point);
1128 bsmtp_transaction_linecount = receive_linecount;
1129 break;
1130
1131
1132 /* The MAIL FROM command requires an address as an operand. All we
1133 do here is to parse it for syntactic correctness. The form "<>" is
1134 a special case which converts into an empty string. The start/end
1135 pointers in the original are not used further for this address, as
1136 it is the canonical extracted address which is all that is kept. */
1137
1138 case MAIL_CMD:
1139 if (sender_address != NULL)
1140 /* The function moan_smtp_batch() does not return. */
1141 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1142
1143 if (smtp_cmd_data[0] == 0)
1144 /* The function moan_smtp_batch() does not return. */
1145 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1146
1147 /* Reset to start of message */
1148
1149 smtp_reset(reset_point);
1150
1151 /* Apply SMTP rewrite */
1152
1153 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1154 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1155 US"", global_rewrite_rules) : smtp_cmd_data;
1156
1157 /* Extract the address; the TRUE flag allows <> as valid */
1158
1159 raw_sender =
1160 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1161 TRUE);
1162
1163 if (raw_sender == NULL)
1164 /* The function moan_smtp_batch() does not return. */
1165 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1166
1167 sender_address = string_copy(raw_sender);
1168
1169 /* Qualify unqualified sender addresses if permitted to do so. */
1170
1171 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1172 {
1173 if (allow_unqualified_sender)
1174 {
1175 sender_address = rewrite_address_qualify(sender_address, FALSE);
1176 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1177 "and rewritten\n", raw_sender);
1178 }
1179 /* The function moan_smtp_batch() does not return. */
1180 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1181 "a domain");
1182 }
1183 break;
1184
1185
1186 /* The RCPT TO command requires an address as an operand. All we do
1187 here is to parse it for syntactic correctness. There may be any number
1188 of RCPT TO commands, specifying multiple senders. We build them all into
1189 a data structure that is in argc/argv format. The start/end values
1190 given by parse_extract_address are not used, as we keep only the
1191 extracted address. */
1192
1193 case RCPT_CMD:
1194 if (sender_address == NULL)
1195 /* The function moan_smtp_batch() does not return. */
1196 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1197
1198 if (smtp_cmd_data[0] == 0)
1199 /* The function moan_smtp_batch() does not return. */
1200 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1201
1202 /* Check maximum number allowed */
1203
1204 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1205 /* The function moan_smtp_batch() does not return. */
1206 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1207 recipients_max_reject? "552": "452");
1208
1209 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1210 recipient address */
1211
1212 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1213 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1214 global_rewrite_rules) : smtp_cmd_data;
1215
1216 /* rfc821_domains = TRUE; << no longer needed */
1217 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1218 &recipient_domain, FALSE);
1219 /* rfc821_domains = FALSE; << no longer needed */
1220
1221 if (recipient == NULL)
1222 /* The function moan_smtp_batch() does not return. */
1223 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1224
1225 /* If the recipient address is unqualified, qualify it if permitted. Then
1226 add it to the list of recipients. */
1227
1228 if (recipient_domain == 0)
1229 {
1230 if (allow_unqualified_recipient)
1231 {
1232 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1233 recipient);
1234 recipient = rewrite_address_qualify(recipient, TRUE);
1235 }
1236 /* The function moan_smtp_batch() does not return. */
1237 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1238 "a domain");
1239 }
1240 receive_add_recipient(recipient, -1);
1241 break;
1242
1243
1244 /* The DATA command is legal only if it follows successful MAIL FROM
1245 and RCPT TO commands. This function is complete when a valid DATA
1246 command is encountered. */
1247
1248 case DATA_CMD:
1249 if (sender_address == NULL || recipients_count <= 0)
1250 {
1251 /* The function moan_smtp_batch() does not return. */
1252 if (sender_address == NULL)
1253 moan_smtp_batch(smtp_cmd_buffer,
1254 "503 MAIL FROM:<sender> command must precede DATA");
1255 else
1256 moan_smtp_batch(smtp_cmd_buffer,
1257 "503 RCPT TO:<recipient> must precede DATA");
1258 }
1259 else
1260 {
1261 done = 3; /* DATA successfully achieved */
1262 message_ended = END_NOTENDED; /* Indicate in middle of message */
1263 }
1264 break;
1265
1266
1267 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1268
1269 case VRFY_CMD:
1270 case EXPN_CMD:
1271 case HELP_CMD:
1272 case NOOP_CMD:
1273 case ETRN_CMD:
1274 bsmtp_transaction_linecount = receive_linecount;
1275 break;
1276
1277
1278 case EOF_CMD:
1279 case QUIT_CMD:
1280 done = 2;
1281 break;
1282
1283
1284 case BADARG_CMD:
1285 /* The function moan_smtp_batch() does not return. */
1286 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1287 break;
1288
1289
1290 case BADCHAR_CMD:
1291 /* The function moan_smtp_batch() does not return. */
1292 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1293 break;
1294
1295
1296 default:
1297 /* The function moan_smtp_batch() does not return. */
1298 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1299 break;
1300 }
1301 }
1302
1303 return done - 2; /* Convert yield values */
1304 }
1305
1306
1307
1308
1309 /*************************************************
1310 * Start an SMTP session *
1311 *************************************************/
1312
1313 /* This function is called at the start of an SMTP session. Thereafter,
1314 smtp_setup_msg() is called to initiate each separate message. This
1315 function does host-specific testing, and outputs the banner line.
1316
1317 Arguments: none
1318 Returns: FALSE if the session can not continue; something has
1319 gone wrong, or the connection to the host is blocked
1320 */
1321
1322 BOOL
1323 smtp_start_session(void)
1324 {
1325 int size = 256;
1326 int ptr, esclen;
1327 uschar *user_msg, *log_msg;
1328 uschar *code, *esc;
1329 uschar *p, *s, *ss;
1330
1331 smtp_connection_start = time(NULL);
1332 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1333 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1334 smtp_ch_index = 0;
1335
1336 /* Default values for certain variables */
1337
1338 helo_seen = esmtp = helo_accept_junk = FALSE;
1339 smtp_mailcmd_count = 0;
1340 count_nonmail = TRUE_UNSET;
1341 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1342 smtp_delay_mail = smtp_rlm_base;
1343 auth_advertised = FALSE;
1344 pipelining_advertised = FALSE;
1345 pipelining_enable = TRUE;
1346 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1347
1348 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1349
1350 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1351 authentication settings from -oMaa to remain in force. */
1352
1353 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1354 authenticated_by = NULL;
1355
1356 #ifdef SUPPORT_TLS
1357 tls_cipher = tls_peerdn = NULL;
1358 tls_advertised = FALSE;
1359 #endif
1360
1361 /* Reset ACL connection variables */
1362
1363 acl_var_c = NULL;
1364
1365 /* Allow for trailing 0 in the command and data buffers. */
1366
1367 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1368 if (smtp_cmd_buffer == NULL)
1369 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1370 "malloc() failed for SMTP command buffer");
1371 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1372
1373 /* For batched input, the protocol setting can be overridden from the
1374 command line by a trusted caller. */
1375
1376 if (smtp_batched_input)
1377 {
1378 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1379 }
1380
1381 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1382 reset later if any of EHLO/AUTH/STARTTLS are received. */
1383
1384 else
1385 received_protocol =
1386 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1387
1388 /* Set up the buffer for inputting using direct read() calls, and arrange to
1389 call the local functions instead of the standard C ones. */
1390
1391 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1392 if (smtp_inbuffer == NULL)
1393 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1394 receive_getc = smtp_getc;
1395 receive_ungetc = smtp_ungetc;
1396 receive_feof = smtp_feof;
1397 receive_ferror = smtp_ferror;
1398 receive_smtp_buffered = smtp_buffered;
1399 smtp_inptr = smtp_inend = smtp_inbuffer;
1400 smtp_had_eof = smtp_had_error = 0;
1401
1402 /* Set up the message size limit; this may be host-specific */
1403
1404 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1405 if (expand_string_message != NULL)
1406 {
1407 if (thismessage_size_limit == -1)
1408 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1409 "%s", expand_string_message);
1410 else
1411 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1412 "%s", expand_string_message);
1413 smtp_closedown(US"Temporary local problem - please try later");
1414 return FALSE;
1415 }
1416
1417 /* When a message is input locally via the -bs or -bS options, sender_host_
1418 unknown is set unless -oMa was used to force an IP address, in which case it
1419 is checked like a real remote connection. When -bs is used from inetd, this
1420 flag is not set, causing the sending host to be checked. The code that deals
1421 with IP source routing (if configured) is never required for -bs or -bS and
1422 the flag sender_host_notsocket is used to suppress it.
1423
1424 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1425 reserve for certain hosts and/or networks. */
1426
1427 if (!sender_host_unknown)
1428 {
1429 int rc;
1430 BOOL reserved_host = FALSE;
1431
1432 /* Look up IP options (source routing info) on the socket if this is not an
1433 -oMa "host", and if any are found, log them and drop the connection.
1434
1435 Linux (and others now, see below) is different to everyone else, so there
1436 has to be some conditional compilation here. Versions of Linux before 2.1.15
1437 used a structure whose name was "options". Somebody finally realized that
1438 this name was silly, and it got changed to "ip_options". I use the
1439 newer name here, but there is a fudge in the script that sets up os.h
1440 to define a macro in older Linux systems.
1441
1442 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1443 glibc 2, which has chosen ip_opts for the structure name. This is now
1444 really a glibc thing rather than a Linux thing, so the condition name
1445 has been changed to reflect this. It is relevant also to GNU/Hurd.
1446
1447 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1448 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1449 a special macro defined in the os.h file.
1450
1451 Some DGUX versions on older hardware appear not to support IP options at
1452 all, so there is now a general macro which can be set to cut out this
1453 support altogether.
1454
1455 How to do this properly in IPv6 is not yet known. */
1456
1457 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1458
1459 #ifdef GLIBC_IP_OPTIONS
1460 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1461 #define OPTSTYLE 1
1462 #else
1463 #define OPTSTYLE 2
1464 #endif
1465 #elif defined DARWIN_IP_OPTIONS
1466 #define OPTSTYLE 2
1467 #else
1468 #define OPTSTYLE 3
1469 #endif
1470
1471 if (!host_checking && !sender_host_notsocket)
1472 {
1473 #if OPTSTYLE == 1
1474 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1475 struct ip_options *ipopt = store_get(optlen);
1476 #elif OPTSTYLE == 2
1477 struct ip_opts ipoptblock;
1478 struct ip_opts *ipopt = &ipoptblock;
1479 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1480 #else
1481 struct ipoption ipoptblock;
1482 struct ipoption *ipopt = &ipoptblock;
1483 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1484 #endif
1485
1486 /* Occasional genuine failures of getsockopt() have been seen - for
1487 example, "reset by peer". Therefore, just log and give up on this
1488 call, unless the error is ENOPROTOOPT. This error is given by systems
1489 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1490 of writing. So for that error, carry on - we just can't do an IP options
1491 check. */
1492
1493 DEBUG(D_receive) debug_printf("checking for IP options\n");
1494
1495 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1496 &optlen) < 0)
1497 {
1498 if (errno != ENOPROTOOPT)
1499 {
1500 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1501 host_and_ident(FALSE), strerror(errno));
1502 smtp_printf("451 SMTP service not available\r\n");
1503 return FALSE;
1504 }
1505 }
1506
1507 /* Deal with any IP options that are set. On the systems I have looked at,
1508 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1509 more logging data than will fit in big_buffer. Nevertheless, after somebody
1510 questioned this code, I've added in some paranoid checking. */
1511
1512 else if (optlen > 0)
1513 {
1514 uschar *p = big_buffer;
1515 uschar *pend = big_buffer + big_buffer_size;
1516 uschar *opt, *adptr;
1517 int optcount;
1518 struct in_addr addr;
1519
1520 #if OPTSTYLE == 1
1521 uschar *optstart = (uschar *)(ipopt->__data);
1522 #elif OPTSTYLE == 2
1523 uschar *optstart = (uschar *)(ipopt->ip_opts);
1524 #else
1525 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1526 #endif
1527
1528 DEBUG(D_receive) debug_printf("IP options exist\n");
1529
1530 Ustrcpy(p, "IP options on incoming call:");
1531 p += Ustrlen(p);
1532
1533 for (opt = optstart; opt != NULL &&
1534 opt < (uschar *)(ipopt) + optlen;)
1535 {
1536 switch (*opt)
1537 {
1538 case IPOPT_EOL:
1539 opt = NULL;
1540 break;
1541
1542 case IPOPT_NOP:
1543 opt++;
1544 break;
1545
1546 case IPOPT_SSRR:
1547 case IPOPT_LSRR:
1548 if (!string_format(p, pend-p, " %s [@%s",
1549 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1550 #if OPTSTYLE == 1
1551 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1552 #elif OPTSTYLE == 2
1553 inet_ntoa(ipopt->ip_dst)))
1554 #else
1555 inet_ntoa(ipopt->ipopt_dst)))
1556 #endif
1557 {
1558 opt = NULL;
1559 break;
1560 }
1561
1562 p += Ustrlen(p);
1563 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1564 adptr = opt + 3;
1565 while (optcount-- > 0)
1566 {
1567 memcpy(&addr, adptr, sizeof(addr));
1568 if (!string_format(p, pend - p - 1, "%s%s",
1569 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1570 {
1571 opt = NULL;
1572 break;
1573 }
1574 p += Ustrlen(p);
1575 adptr += sizeof(struct in_addr);
1576 }
1577 *p++ = ']';
1578 opt += opt[1];
1579 break;
1580
1581 default:
1582 {
1583 int i;
1584 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1585 Ustrcat(p, "[ ");
1586 p += 2;
1587 for (i = 0; i < opt[1]; i++)
1588 {
1589 sprintf(CS p, "%2.2x ", opt[i]);
1590 p += 3;
1591 }
1592 *p++ = ']';
1593 }
1594 opt += opt[1];
1595 break;
1596 }
1597 }
1598
1599 *p = 0;
1600 log_write(0, LOG_MAIN, "%s", big_buffer);
1601
1602 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1603
1604 log_write(0, LOG_MAIN|LOG_REJECT,
1605 "connection from %s refused (IP options)", host_and_ident(FALSE));
1606
1607 smtp_printf("554 SMTP service not available\r\n");
1608 return FALSE;
1609 }
1610
1611 /* Length of options = 0 => there are no options */
1612
1613 else DEBUG(D_receive) debug_printf("no IP options found\n");
1614 }
1615 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1616
1617 /* Set keep-alive in socket options. The option is on by default. This
1618 setting is an attempt to get rid of some hanging connections that stick in
1619 read() when the remote end (usually a dialup) goes away. */
1620
1621 if (smtp_accept_keepalive && !sender_host_notsocket)
1622 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1623
1624 /* If the current host matches host_lookup, set the name by doing a
1625 reverse lookup. On failure, sender_host_name will be NULL and
1626 host_lookup_failed will be TRUE. This may or may not be serious - optional
1627 checks later. */
1628
1629 if (verify_check_host(&host_lookup) == OK)
1630 {
1631 (void)host_name_lookup();
1632 host_build_sender_fullhost();
1633 }
1634
1635 /* Delay this until we have the full name, if it is looked up. */
1636
1637 set_process_info("handling incoming connection from %s",
1638 host_and_ident(FALSE));
1639
1640 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1641 smtps port for use with older style SSL MTAs. */
1642
1643 #ifdef SUPPORT_TLS
1644 if (tls_on_connect &&
1645 tls_server_start(tls_require_ciphers,
1646 gnutls_require_mac, gnutls_require_kx, gnutls_require_proto) != OK)
1647 return FALSE;
1648 #endif
1649
1650 /* Test for explicit connection rejection */
1651
1652 if (verify_check_host(&host_reject_connection) == OK)
1653 {
1654 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1655 "from %s (host_reject_connection)", host_and_ident(FALSE));
1656 smtp_printf("554 SMTP service not available\r\n");
1657 return FALSE;
1658 }
1659
1660 /* Test with TCP Wrappers if so configured. There is a problem in that
1661 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1662 such as disks dying. In these cases, it is desirable to reject with a 4xx
1663 error instead of a 5xx error. There isn't a "right" way to detect such
1664 problems. The following kludge is used: errno is zeroed before calling
1665 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1666 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1667 not exist). */
1668
1669 #ifdef USE_TCP_WRAPPERS
1670 errno = 0;
1671 if (!hosts_ctl("exim",
1672 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1673 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1674 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1675 {
1676 if (errno == 0 || errno == ENOENT)
1677 {
1678 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1679 log_write(L_connection_reject,
1680 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1681 "(tcp wrappers)", host_and_ident(FALSE));
1682 smtp_printf("554 SMTP service not available\r\n");
1683 }
1684 else
1685 {
1686 int save_errno = errno;
1687 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1688 "errno value %d\n", save_errno);
1689 log_write(L_connection_reject,
1690 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1691 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1692 smtp_printf("451 Temporary local problem - please try later\r\n");
1693 }
1694 return FALSE;
1695 }
1696 #endif
1697
1698 /* Check for reserved slots. The value of smtp_accept_count has already been
1699 incremented to include this process. */
1700
1701 if (smtp_accept_max > 0 &&
1702 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
1703 {
1704 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1705 {
1706 log_write(L_connection_reject,
1707 LOG_MAIN, "temporarily refused connection from %s: not in "
1708 "reserve list: connected=%d max=%d reserve=%d%s",
1709 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
1710 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1711 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1712 "please try again later\r\n", smtp_active_hostname);
1713 return FALSE;
1714 }
1715 reserved_host = TRUE;
1716 }
1717
1718 /* If a load level above which only messages from reserved hosts are
1719 accepted is set, check the load. For incoming calls via the daemon, the
1720 check is done in the superior process if there are no reserved hosts, to
1721 save a fork. In all cases, the load average will already be available
1722 in a global variable at this point. */
1723
1724 if (smtp_load_reserve >= 0 &&
1725 load_average > smtp_load_reserve &&
1726 !reserved_host &&
1727 verify_check_host(&smtp_reserve_hosts) != OK)
1728 {
1729 log_write(L_connection_reject,
1730 LOG_MAIN, "temporarily refused connection from %s: not in "
1731 "reserve list and load average = %.2f", host_and_ident(FALSE),
1732 (double)load_average/1000.0);
1733 smtp_printf("421 %s: Too much load; please try again later\r\n",
1734 smtp_active_hostname);
1735 return FALSE;
1736 }
1737
1738 /* Determine whether unqualified senders or recipients are permitted
1739 for this host. Unfortunately, we have to do this every time, in order to
1740 set the flags so that they can be inspected when considering qualifying
1741 addresses in the headers. For a site that permits no qualification, this
1742 won't take long, however. */
1743
1744 allow_unqualified_sender =
1745 verify_check_host(&sender_unqualified_hosts) == OK;
1746
1747 allow_unqualified_recipient =
1748 verify_check_host(&recipient_unqualified_hosts) == OK;
1749
1750 /* Determine whether HELO/EHLO is required for this host. The requirement
1751 can be hard or soft. */
1752
1753 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1754 if (!helo_required)
1755 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1756
1757 /* Determine whether this hosts is permitted to send syntactic junk
1758 after a HELO or EHLO command. */
1759
1760 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1761 }
1762
1763 /* For batch SMTP input we are now done. */
1764
1765 if (smtp_batched_input) return TRUE;
1766
1767 /* Run the ACL if it exists */
1768
1769 user_msg = NULL;
1770 if (acl_smtp_connect != NULL)
1771 {
1772 int rc;
1773 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1774 &log_msg);
1775 if (rc != OK)
1776 {
1777 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1778 return FALSE;
1779 }
1780 }
1781
1782 /* Output the initial message for a two-way SMTP connection. It may contain
1783 newlines, which then cause a multi-line response to be given. */
1784
1785 code = US"220"; /* Default status code */
1786 esc = US""; /* Default extended status code */
1787 esclen = 0; /* Length of esc */
1788
1789 if (user_msg == NULL)
1790 {
1791 s = expand_string(smtp_banner);
1792 if (s == NULL)
1793 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1794 "failed: %s", smtp_banner, expand_string_message);
1795 }
1796 else
1797 {
1798 int codelen = 3;
1799 s = user_msg;
1800 smtp_message_code(&code, &codelen, &s, NULL);
1801 if (codelen > 4)
1802 {
1803 esc = code + 4;
1804 esclen = codelen - 4;
1805 }
1806 }
1807
1808 /* Remove any terminating newlines; might as well remove trailing space too */
1809
1810 p = s + Ustrlen(s);
1811 while (p > s && isspace(p[-1])) p--;
1812 *p = 0;
1813
1814 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1815 is all contained in a single IP packet. The original code wrote out the
1816 greeting using several calls to fprint/fputc, and on busy servers this could
1817 cause it to be split over more than one packet - which caused CC:Mail to fall
1818 over when it got the second part of the greeting after sending its first
1819 command. Sigh. To try to avoid this, build the complete greeting message
1820 first, and output it in one fell swoop. This gives a better chance of it
1821 ending up as a single packet. */
1822
1823 ss = store_get(size);
1824 ptr = 0;
1825
1826 p = s;
1827 do /* At least once, in case we have an empty string */
1828 {
1829 int len;
1830 uschar *linebreak = Ustrchr(p, '\n');
1831 ss = string_cat(ss, &size, &ptr, code, 3);
1832 if (linebreak == NULL)
1833 {
1834 len = Ustrlen(p);
1835 ss = string_cat(ss, &size, &ptr, US" ", 1);
1836 }
1837 else
1838 {
1839 len = linebreak - p;
1840 ss = string_cat(ss, &size, &ptr, US"-", 1);
1841 }
1842 ss = string_cat(ss, &size, &ptr, esc, esclen);
1843 ss = string_cat(ss, &size, &ptr, p, len);
1844 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1845 p += len;
1846 if (linebreak != NULL) p++;
1847 }
1848 while (*p != 0);
1849
1850 ss[ptr] = 0; /* string_cat leaves room for this */
1851
1852 /* Before we write the banner, check that there is no input pending, unless
1853 this synchronisation check is disabled. */
1854
1855 if (!check_sync())
1856 {
1857 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1858 "synchronization error (input sent without waiting for greeting): "
1859 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1860 string_printing(smtp_inptr));
1861 smtp_printf("554 SMTP synchronization error\r\n");
1862 return FALSE;
1863 }
1864
1865 /* Now output the banner */
1866
1867 smtp_printf("%s", ss);
1868 return TRUE;
1869 }
1870
1871
1872
1873
1874
1875 /*************************************************
1876 * Handle SMTP syntax and protocol errors *
1877 *************************************************/
1878
1879 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1880 to do so. Then transmit the error response. The return value depends on the
1881 number of syntax and protocol errors in this SMTP session.
1882
1883 Arguments:
1884 type error type, given as a log flag bit
1885 code response code; <= 0 means don't send a response
1886 data data to reflect in the response (can be NULL)
1887 errmess the error message
1888
1889 Returns: -1 limit of syntax/protocol errors NOT exceeded
1890 +1 limit of syntax/protocol errors IS exceeded
1891
1892 These values fit in with the values of the "done" variable in the main
1893 processing loop in smtp_setup_msg(). */
1894
1895 static int
1896 synprot_error(int type, int code, uschar *data, uschar *errmess)
1897 {
1898 int yield = -1;
1899
1900 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1901 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1902 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1903
1904 if (++synprot_error_count > smtp_max_synprot_errors)
1905 {
1906 yield = 1;
1907 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1908 "syntax or protocol errors (last command was \"%s\")",
1909 host_and_ident(FALSE), smtp_cmd_buffer);
1910 }
1911
1912 if (code > 0)
1913 {
1914 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1915 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1916 if (yield == 1)
1917 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1918 }
1919
1920 return yield;
1921 }
1922
1923
1924
1925
1926 /*************************************************
1927 * Log incomplete transactions *
1928 *************************************************/
1929
1930 /* This function is called after a transaction has been aborted by RSET, QUIT,
1931 connection drops or other errors. It logs the envelope information received
1932 so far in order to preserve address verification attempts.
1933
1934 Argument: string to indicate what aborted the transaction
1935 Returns: nothing
1936 */
1937
1938 static void
1939 incomplete_transaction_log(uschar *what)
1940 {
1941 if (sender_address == NULL || /* No transaction in progress */
1942 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1943 ) return;
1944
1945 /* Build list of recipients for logging */
1946
1947 if (recipients_count > 0)
1948 {
1949 int i;
1950 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1951 for (i = 0; i < recipients_count; i++)
1952 raw_recipients[i] = recipients_list[i].address;
1953 raw_recipients_count = recipients_count;
1954 }
1955
1956 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1957 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1958 }
1959
1960
1961
1962
1963 /*************************************************
1964 * Send SMTP response, possibly multiline *
1965 *************************************************/
1966
1967 /* There are, it seems, broken clients out there that cannot handle multiline
1968 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1969 output nothing for non-final calls, and only the first line for anything else.
1970
1971 Arguments:
1972 code SMTP code, may involve extended status codes
1973 codelen length of smtp code; if > 4 there's an ESC
1974 final FALSE if the last line isn't the final line
1975 msg message text, possibly containing newlines
1976
1977 Returns: nothing
1978 */
1979
1980 void
1981 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
1982 {
1983 int esclen = 0;
1984 uschar *esc = US"";
1985
1986 if (!final && no_multiline_responses) return;
1987
1988 if (codelen > 4)
1989 {
1990 esc = code + 4;
1991 esclen = codelen - 4;
1992 }
1993
1994 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
1995 have had the same. Note: this code is also present in smtp_printf(). It would
1996 be tidier to have it only in one place, but when it was added, it was easier to
1997 do it that way, so as not to have to mess with the code for the RCPT command,
1998 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
1999
2000 if (rcpt_in_progress)
2001 {
2002 if (rcpt_smtp_response == NULL)
2003 rcpt_smtp_response = string_copy(msg);
2004 else if (rcpt_smtp_response_same &&
2005 Ustrcmp(rcpt_smtp_response, msg) != 0)
2006 rcpt_smtp_response_same = FALSE;
2007 rcpt_in_progress = FALSE;
2008 }
2009
2010 /* Not output the message, splitting it up into multiple lines if necessary. */
2011
2012 for (;;)
2013 {
2014 uschar *nl = Ustrchr(msg, '\n');
2015 if (nl == NULL)
2016 {
2017 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2018 return;
2019 }
2020 else if (nl[1] == 0 || no_multiline_responses)
2021 {
2022 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2023 (int)(nl - msg), msg);
2024 return;
2025 }
2026 else
2027 {
2028 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2029 msg = nl + 1;
2030 while (isspace(*msg)) msg++;
2031 }
2032 }
2033 }
2034
2035
2036
2037
2038 /*************************************************
2039 * Parse user SMTP message *
2040 *************************************************/
2041
2042 /* This function allows for user messages overriding the response code details
2043 by providing a suitable response code string at the start of the message
2044 user_msg. Check the message for starting with a response code and optionally an
2045 extended status code. If found, check that the first digit is valid, and if so,
2046 change the code pointer and length to use the replacement. An invalid code
2047 causes a panic log; in this case, if the log messages is the same as the user
2048 message, we must also adjust the value of the log message to show the code that
2049 is actually going to be used (the original one).
2050
2051 This function is global because it is called from receive.c as well as within
2052 this module.
2053
2054 Note that the code length returned includes the terminating whitespace
2055 character, which is always included in the regex match.
2056
2057 Arguments:
2058 code SMTP code, may involve extended status codes
2059 codelen length of smtp code; if > 4 there's an ESC
2060 msg message text
2061 log_msg optional log message, to be adjusted with the new SMTP code
2062
2063 Returns: nothing
2064 */
2065
2066 void
2067 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2068 {
2069 int n;
2070 int ovector[3];
2071
2072 if (msg == NULL || *msg == NULL) return;
2073
2074 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2075 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2076 if (n < 0) return;
2077
2078 if ((*msg)[0] != (*code)[0])
2079 {
2080 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2081 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2082 if (log_msg != NULL && *log_msg == *msg)
2083 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2084 }
2085 else
2086 {
2087 *code = *msg;
2088 *codelen = ovector[1]; /* Includes final space */
2089 }
2090 *msg += ovector[1]; /* Chop the code off the message */
2091 return;
2092 }
2093
2094
2095
2096
2097 /*************************************************
2098 * Handle an ACL failure *
2099 *************************************************/
2100
2101 /* This function is called when acl_check() fails. As well as calls from within
2102 this module, it is called from receive.c for an ACL after DATA. It sorts out
2103 logging the incident, and sets up the error response. A message containing
2104 newlines is turned into a multiline SMTP response, but for logging, only the
2105 first line is used.
2106
2107 There's a table of default permanent failure response codes to use in
2108 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2109 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2110 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2111 state, because there are broken clients that try VRFY before RCPT. A 5xx
2112 response should be given only when the address is positively known to be
2113 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2114 503.
2115
2116 From Exim 4.63, it is possible to override the response code details by
2117 providing a suitable response code string at the start of the message provided
2118 in user_msg. The code's first digit is checked for validity.
2119
2120 Arguments:
2121 where where the ACL was called from
2122 rc the failure code
2123 user_msg a message that can be included in an SMTP response
2124 log_msg a message for logging
2125
2126 Returns: 0 in most cases
2127 2 if the failure code was FAIL_DROP, in which case the
2128 SMTP connection should be dropped (this value fits with the
2129 "done" variable in smtp_setup_msg() below)
2130 */
2131
2132 int
2133 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2134 {
2135 BOOL drop = rc == FAIL_DROP;
2136 int codelen = 3;
2137 uschar *smtp_code;
2138 uschar *lognl;
2139 uschar *sender_info = US"";
2140 uschar *what =
2141 #ifdef WITH_CONTENT_SCAN
2142 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2143 #endif
2144 (where == ACL_WHERE_PREDATA)? US"DATA" :
2145 (where == ACL_WHERE_DATA)? US"after DATA" :
2146 (smtp_cmd_data == NULL)?
2147 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2148 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2149
2150 if (drop) rc = FAIL;
2151
2152 /* Set the default SMTP code, and allow a user message to change it. */
2153
2154 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2155 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2156
2157 /* We used to have sender_address here; however, there was a bug that was not
2158 updating sender_address after a rewrite during a verify. When this bug was
2159 fixed, sender_address at this point became the rewritten address. I'm not sure
2160 this is what should be logged, so I've changed to logging the unrewritten
2161 address to retain backward compatibility. */
2162
2163 #ifndef WITH_CONTENT_SCAN
2164 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2165 #else
2166 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2167 #endif
2168 {
2169 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
2170 sender_address_unrewritten : sender_address);
2171 }
2172
2173 /* If there's been a sender verification failure with a specific message, and
2174 we have not sent a response about it yet, do so now, as a preliminary line for
2175 failures, but not defers. However, always log it for defer, and log it for fail
2176 unless the sender_verify_fail log selector has been turned off. */
2177
2178 if (sender_verified_failed != NULL &&
2179 !testflag(sender_verified_failed, af_sverify_told))
2180 {
2181 BOOL save_rcpt_in_progress = rcpt_in_progress;
2182 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2183
2184 setflag(sender_verified_failed, af_sverify_told);
2185
2186 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2187 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2188 host_and_ident(TRUE),
2189 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2190 sender_verified_failed->address,
2191 (sender_verified_failed->message == NULL)? US"" :
2192 string_sprintf(": %s", sender_verified_failed->message));
2193
2194 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2195 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2196 testflag(sender_verified_failed, af_verify_pmfail)?
2197 "Postmaster verification failed while checking <%s>\n%s\n"
2198 "Several RFCs state that you are required to have a postmaster\n"
2199 "mailbox for each mail domain. This host does not accept mail\n"
2200 "from domains whose servers reject the postmaster address."
2201 :
2202 testflag(sender_verified_failed, af_verify_nsfail)?
2203 "Callback setup failed while verifying <%s>\n%s\n"
2204 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2205 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2206 "RFC requirements, and stops you from receiving standard bounce\n"
2207 "messages. This host does not accept mail from domains whose servers\n"
2208 "refuse bounces."
2209 :
2210 "Verification failed for <%s>\n%s",
2211 sender_verified_failed->address,
2212 sender_verified_failed->user_message));
2213
2214 rcpt_in_progress = save_rcpt_in_progress;
2215 }
2216
2217 /* Sort out text for logging */
2218
2219 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2220 lognl = Ustrchr(log_msg, '\n');
2221 if (lognl != NULL) *lognl = 0;
2222
2223 /* Send permanent failure response to the command, but the code used isn't
2224 always a 5xx one - see comments at the start of this function. If the original
2225 rc was FAIL_DROP we drop the connection and yield 2. */
2226
2227 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2228 US"Administrative prohibition" : user_msg);
2229
2230 /* Send temporary failure response to the command. Don't give any details,
2231 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2232 verb, and for a header verify when smtp_return_error_details is set.
2233
2234 This conditional logic is all somewhat of a mess because of the odd
2235 interactions between temp_details and return_error_details. One day it should
2236 be re-implemented in a tidier fashion. */
2237
2238 else
2239 {
2240 if (acl_temp_details && user_msg != NULL)
2241 {
2242 if (smtp_return_error_details &&
2243 sender_verified_failed != NULL &&
2244 sender_verified_failed->message != NULL)
2245 {
2246 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2247 }
2248 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2249 }
2250 else
2251 smtp_respond(smtp_code, codelen, TRUE,
2252 US"Temporary local problem - please try later");
2253 }
2254
2255 /* Log the incident to the logs that are specified by log_reject_target
2256 (default main, reject). This can be empty to suppress logging of rejections. If
2257 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2258 is closing if required and return 2. */
2259
2260 if (log_reject_target != 0)
2261 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2262 host_and_ident(TRUE),
2263 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2264
2265 if (!drop) return 0;
2266
2267 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2268 smtp_get_connection_info());
2269 return 2;
2270 }
2271
2272
2273
2274
2275 /*************************************************
2276 * Verify HELO argument *
2277 *************************************************/
2278
2279 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2280 matched. It is also called from ACL processing if verify = helo is used and
2281 verification was not previously tried (i.e. helo_try_verify_hosts was not
2282 matched). The result of its processing is to set helo_verified and
2283 helo_verify_failed. These variables should both be FALSE for this function to
2284 be called.
2285
2286 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2287 for IPv6 ::ffff: literals.
2288
2289 Argument: none
2290 Returns: TRUE if testing was completed;
2291 FALSE on a temporary failure
2292 */
2293
2294 BOOL
2295 smtp_verify_helo(void)
2296 {
2297 BOOL yield = TRUE;
2298
2299 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2300 sender_helo_name);
2301
2302 if (sender_helo_name == NULL)
2303 {
2304 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2305 }
2306
2307 /* Deal with the case of -bs without an IP address */
2308
2309 else if (sender_host_address == NULL)
2310 {
2311 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2312 helo_verified = TRUE;
2313 }
2314
2315 /* Deal with the more common case when there is a sending IP address */
2316
2317 else if (sender_helo_name[0] == '[')
2318 {
2319 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2320 Ustrlen(sender_host_address)) == 0;
2321
2322 #if HAVE_IPV6
2323 if (!helo_verified)
2324 {
2325 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2326 helo_verified = Ustrncmp(sender_helo_name + 1,
2327 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2328 }
2329 #endif
2330
2331 HDEBUG(D_receive)
2332 { if (helo_verified) debug_printf("matched host address\n"); }
2333 }
2334
2335 /* Do a reverse lookup if one hasn't already given a positive or negative
2336 response. If that fails, or the name doesn't match, try checking with a forward
2337 lookup. */
2338
2339 else
2340 {
2341 if (sender_host_name == NULL && !host_lookup_failed)
2342 yield = host_name_lookup() != DEFER;
2343
2344 /* If a host name is known, check it and all its aliases. */
2345
2346 if (sender_host_name != NULL)
2347 {
2348 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2349
2350 if (helo_verified)
2351 {
2352 HDEBUG(D_receive) debug_printf("matched host name\n");
2353 }
2354 else
2355 {
2356 uschar **aliases = sender_host_aliases;
2357 while (*aliases != NULL)
2358 {
2359 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2360 if (helo_verified) break;
2361 }
2362 HDEBUG(D_receive)
2363 {
2364 if (helo_verified)
2365 debug_printf("matched alias %s\n", *(--aliases));
2366 }
2367 }
2368 }
2369
2370 /* Final attempt: try a forward lookup of the helo name */
2371
2372 if (!helo_verified)
2373 {
2374 int rc;
2375 host_item h;
2376 h.name = sender_helo_name;
2377 h.address = NULL;
2378 h.mx = MX_NONE;
2379 h.next = NULL;
2380 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2381 sender_helo_name);
2382 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2383 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2384 {
2385 host_item *hh = &h;
2386 while (hh != NULL)
2387 {
2388 if (Ustrcmp(hh->address, sender_host_address) == 0)
2389 {
2390 helo_verified = TRUE;
2391 HDEBUG(D_receive)
2392 debug_printf("IP address for %s matches calling address\n",
2393 sender_helo_name);
2394 break;
2395 }
2396 hh = hh->next;
2397 }
2398 }
2399 }
2400 }
2401
2402 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2403 return yield;
2404 }
2405
2406
2407
2408
2409 /*************************************************
2410 * Send user response message *
2411 *************************************************/
2412
2413 /* This function is passed a default response code and a user message. It calls
2414 smtp_message_code() to check and possibly modify the response code, and then
2415 calls smtp_respond() to transmit the response. I put this into a function
2416 just to avoid a lot of repetition.
2417
2418 Arguments:
2419 code the response code
2420 user_msg the user message
2421
2422 Returns: nothing
2423 */
2424
2425 static void
2426 smtp_user_msg(uschar *code, uschar *user_msg)
2427 {
2428 int len = 3;
2429 smtp_message_code(&code, &len, &user_msg, NULL);
2430 smtp_respond(code, len, TRUE, user_msg);
2431 }
2432
2433
2434
2435
2436 /*************************************************
2437 * Initialize for SMTP incoming message *
2438 *************************************************/
2439
2440 /* This function conducts the initial dialogue at the start of an incoming SMTP
2441 message, and builds a list of recipients. However, if the incoming message
2442 is part of a batch (-bS option) a separate function is called since it would
2443 be messy having tests splattered about all over this function. This function
2444 therefore handles the case where interaction is occurring. The input and output
2445 files are set up in smtp_in and smtp_out.
2446
2447 The global recipients_list is set to point to a vector of recipient_item
2448 blocks, whose number is given by recipients_count. This is extended by the
2449 receive_add_recipient() function. The global variable sender_address is set to
2450 the sender's address. The yield is +1 if a message has been successfully
2451 started, 0 if a QUIT command was encountered or the connection was refused from
2452 the particular host, or -1 if the connection was lost.
2453
2454 Argument: none
2455
2456 Returns: > 0 message successfully started (reached DATA)
2457 = 0 QUIT read or end of file reached or call refused
2458 < 0 lost connection
2459 */
2460
2461 int
2462 smtp_setup_msg(void)
2463 {
2464 int done = 0;
2465 BOOL toomany = FALSE;
2466 BOOL discarded = FALSE;
2467 BOOL last_was_rej_mail = FALSE;
2468 BOOL last_was_rcpt = FALSE;
2469 void *reset_point = store_get(0);
2470
2471 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2472
2473 /* Reset for start of new message. We allow one RSET not to be counted as a
2474 nonmail command, for those MTAs that insist on sending it between every
2475 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2476 TLS between messages (an Exim client may do this if it has messages queued up
2477 for the host). Note: we do NOT reset AUTH at this point. */
2478
2479 smtp_reset(reset_point);
2480 message_ended = END_NOTSTARTED;
2481
2482 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2483 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2484 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2485 #ifdef SUPPORT_TLS
2486 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2487 #endif
2488
2489 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2490
2491 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2492
2493 /* Batched SMTP is handled in a different function. */
2494
2495 if (smtp_batched_input) return smtp_setup_batch_msg();
2496
2497 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2498 value. The values are 2 larger than the required yield of the function. */
2499
2500 while (done <= 0)
2501 {
2502 uschar **argv;
2503 uschar *etrn_command;
2504 uschar *etrn_serialize_key;
2505 uschar *errmess;
2506 uschar *log_msg, *smtp_code;
2507 uschar *user_msg = NULL;
2508 uschar *recipient = NULL;
2509 uschar *hello = NULL;
2510 uschar *set_id = NULL;
2511 uschar *s, *ss;
2512 BOOL was_rej_mail = FALSE;
2513 BOOL was_rcpt = FALSE;
2514 void (*oldsignal)(int);
2515 pid_t pid;
2516 int start, end, sender_domain, recipient_domain;
2517 int ptr, size, rc;
2518 int c, i;
2519 auth_instance *au;
2520
2521 switch(smtp_read_command(TRUE))
2522 {
2523 /* The AUTH command is not permitted to occur inside a transaction, and may
2524 occur successfully only once per connection. Actually, that isn't quite
2525 true. When TLS is started, all previous information about a connection must
2526 be discarded, so a new AUTH is permitted at that time.
2527
2528 AUTH may only be used when it has been advertised. However, it seems that
2529 there are clients that send AUTH when it hasn't been advertised, some of
2530 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2531 So there's a get-out that allows this to happen.
2532
2533 AUTH is initially labelled as a "nonmail command" so that one occurrence
2534 doesn't get counted. We change the label here so that multiple failing
2535 AUTHS will eventually hit the nonmail threshold. */
2536
2537 case AUTH_CMD:
2538 HAD(SCH_AUTH);
2539 authentication_failed = TRUE;
2540 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2541
2542 if (!auth_advertised && !allow_auth_unadvertised)
2543 {
2544 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2545 US"AUTH command used when not advertised");
2546 break;
2547 }
2548 if (sender_host_authenticated != NULL)
2549 {
2550 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2551 US"already authenticated");
2552 break;
2553 }
2554 if (sender_address != NULL)
2555 {
2556 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2557 US"not permitted in mail transaction");
2558 break;
2559 }
2560
2561 /* Check the ACL */
2562
2563 if (acl_smtp_auth != NULL)
2564 {
2565 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2566 if (rc != OK)
2567 {
2568 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2569 break;
2570 }
2571 }
2572
2573 /* Find the name of the requested authentication mechanism. */
2574
2575 s = smtp_cmd_data;
2576 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
2577 {
2578 if (!isalnum(c) && c != '-' && c != '_')
2579 {
2580 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2581 US"invalid character in authentication mechanism name");
2582 goto COMMAND_LOOP;
2583 }
2584 smtp_cmd_data++;
2585 }
2586
2587 /* If not at the end of the line, we must be at white space. Terminate the
2588 name and move the pointer on to any data that may be present. */
2589
2590 if (*smtp_cmd_data != 0)
2591 {
2592 *smtp_cmd_data++ = 0;
2593 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
2594 }
2595
2596 /* Search for an authentication mechanism which is configured for use
2597 as a server and which has been advertised (unless, sigh, allow_auth_
2598 unadvertised is set). */
2599
2600 for (au = auths; au != NULL; au = au->next)
2601 {
2602 if (strcmpic(s, au->public_name) == 0 && au->server &&
2603 (au->advertised || allow_auth_unadvertised)) break;
2604 }
2605
2606 if (au == NULL)
2607 {
2608 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2609 string_sprintf("%s authentication mechanism not supported", s));
2610 break;
2611 }
2612
2613 /* Run the checking code, passing the remainder of the command line as
2614 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2615 it as the only set numerical variable. The authenticator may set $auth<n>
2616 and also set other numeric variables. The $auth<n> variables are preferred
2617 nowadays; the numerical variables remain for backwards compatibility.
2618
2619 Afterwards, have a go at expanding the set_id string, even if
2620 authentication failed - for bad passwords it can be useful to log the
2621 userid. On success, require set_id to expand and exist, and put it in
2622 authenticated_id. Save this in permanent store, as the working store gets
2623 reset at HELO, RSET, etc. */
2624
2625 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2626 expand_nmax = 0;
2627 expand_nlength[0] = 0; /* $0 contains nothing */
2628
2629 c = (au->info->servercode)(au, smtp_cmd_data);
2630 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2631 expand_nmax = -1; /* Reset numeric variables */
2632 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2633
2634 /* The value of authenticated_id is stored in the spool file and printed in
2635 log lines. It must not contain binary zeros or newline characters. In
2636 normal use, it never will, but when playing around or testing, this error
2637 can (did) happen. To guard against this, ensure that the id contains only
2638 printing characters. */
2639
2640 if (set_id != NULL) set_id = string_printing(set_id);
2641
2642 /* For the non-OK cases, set up additional logging data if set_id
2643 is not empty. */
2644
2645 if (c != OK)
2646 {
2647 if (set_id != NULL && *set_id != 0)
2648 set_id = string_sprintf(" (set_id=%s)", set_id);
2649 else set_id = US"";
2650 }
2651
2652 /* Switch on the result */
2653
2654 switch(c)
2655 {
2656 case OK:
2657 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2658 {
2659 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2660 sender_host_authenticated = au->name;
2661 authentication_failed = FALSE;
2662 received_protocol =
2663 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2664 ((sender_host_address != NULL)? pnlocal : 0);
2665 s = ss = US"235 Authentication succeeded";
2666 authenticated_by = au;
2667 break;
2668 }
2669
2670 /* Authentication succeeded, but we failed to expand the set_id string.
2671 Treat this as a temporary error. */
2672
2673 auth_defer_msg = expand_string_message;
2674 /* Fall through */
2675
2676 case DEFER:
2677 s = string_sprintf("435 Unable to authenticate at present%s",
2678 auth_defer_user_msg);
2679 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2680 set_id, auth_defer_msg);
2681 break;
2682
2683 case BAD64:
2684 s = ss = US"501 Invalid base64 data";
2685 break;
2686
2687 case CANCELLED:
2688 s = ss = US"501 Authentication cancelled";
2689 break;
2690
2691 case UNEXPECTED:
2692 s = ss = US"553 Initial data not expected";
2693 break;
2694
2695 case FAIL:
2696 s = US"535 Incorrect authentication data";
2697 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2698 break;
2699
2700 default:
2701 s = US"435 Internal error";
2702 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2703 "check", set_id, c);
2704 break;
2705 }
2706
2707 smtp_printf("%s\r\n", s);
2708 if (c != OK)
2709 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2710 au->name, host_and_ident(FALSE), ss);
2711
2712 break; /* AUTH_CMD */
2713
2714 /* The HELO/EHLO commands are permitted to appear in the middle of a
2715 session as well as at the beginning. They have the effect of a reset in
2716 addition to their other functions. Their absence at the start cannot be
2717 taken to be an error.
2718
2719 RFC 2821 says:
2720
2721 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2722 or 502 failure replies MUST be returned as appropriate. The SMTP
2723 server MUST stay in the same state after transmitting these replies
2724 that it was in before the EHLO was received.
2725
2726 Therefore, we do not do the reset until after checking the command for
2727 acceptability. This change was made for Exim release 4.11. Previously
2728 it did the reset first. */
2729
2730 case HELO_CMD:
2731 HAD(SCH_HELO);
2732 hello = US"HELO";
2733 esmtp = FALSE;
2734 goto HELO_EHLO;
2735
2736 case EHLO_CMD:
2737 HAD(SCH_EHLO);
2738 hello = US"EHLO";
2739 esmtp = TRUE;
2740
2741 HELO_EHLO: /* Common code for HELO and EHLO */
2742 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2743 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2744
2745 /* Reject the HELO if its argument was invalid or non-existent. A
2746 successful check causes the argument to be saved in malloc store. */
2747
2748 if (!check_helo(smtp_cmd_data))
2749 {
2750 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2751
2752 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2753 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2754 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2755 string_printing(smtp_cmd_argument));
2756
2757 if (++synprot_error_count > smtp_max_synprot_errors)
2758 {
2759 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2760 "syntax or protocol errors (last command was \"%s\")",
2761 host_and_ident(FALSE), smtp_cmd_buffer);
2762 done = 1;
2763 }
2764
2765 break;
2766 }
2767
2768 /* If sender_host_unknown is true, we have got here via the -bs interface,
2769 not called from inetd. Otherwise, we are running an IP connection and the
2770 host address will be set. If the helo name is the primary name of this
2771 host and we haven't done a reverse lookup, force one now. If helo_required
2772 is set, ensure that the HELO name matches the actual host. If helo_verify
2773 is set, do the same check, but softly. */
2774
2775 if (!sender_host_unknown)
2776 {
2777 BOOL old_helo_verified = helo_verified;
2778 uschar *p = smtp_cmd_data;
2779
2780 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2781 *p = 0;
2782
2783 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2784 because otherwise the log can be confusing. */
2785
2786 if (sender_host_name == NULL &&
2787 (deliver_domain = sender_helo_name, /* set $domain */
2788 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2789 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2790 (void)host_name_lookup();
2791
2792 /* Rebuild the fullhost info to include the HELO name (and the real name
2793 if it was looked up.) */
2794
2795 host_build_sender_fullhost(); /* Rebuild */
2796 set_process_info("handling%s incoming connection from %s",
2797 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2798
2799 /* Verify if configured. This doesn't give much security, but it does
2800 make some people happy to be able to do it. If helo_required is set,
2801 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2802 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2803 now obsolescent, since the verification can now be requested selectively
2804 at ACL time. */
2805
2806 helo_verified = helo_verify_failed = FALSE;
2807 if (helo_required || helo_verify)
2808 {
2809 BOOL tempfail = !smtp_verify_helo();
2810 if (!helo_verified)
2811 {
2812 if (helo_required)
2813 {
2814 smtp_printf("%d %s argument does not match calling host\r\n",
2815 tempfail? 451 : 550, hello);
2816 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2817 tempfail? "temporarily " : "",
2818 hello, sender_helo_name, host_and_ident(FALSE));
2819 helo_verified = old_helo_verified;
2820 break; /* End of HELO/EHLO processing */
2821 }
2822 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2823 "helo_try_verify_hosts\n", hello);
2824 }
2825 }
2826 }
2827
2828 #ifdef EXPERIMENTAL_SPF
2829 /* set up SPF context */
2830 spf_init(sender_helo_name, sender_host_address);
2831 #endif
2832
2833 /* Apply an ACL check if one is defined; afterwards, recheck
2834 synchronization in case the client started sending in a delay. */
2835
2836 if (acl_smtp_helo != NULL)
2837 {
2838 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2839 if (rc != OK)
2840 {
2841 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2842 sender_helo_name = NULL;
2843 host_build_sender_fullhost(); /* Rebuild */
2844 break;
2845 }
2846 else if (!check_sync()) goto SYNC_FAILURE;
2847 }
2848
2849 /* Generate an OK reply. The default string includes the ident if present,
2850 and also the IP address if present. Reflecting back the ident is intended
2851 as a deterrent to mail forgers. For maximum efficiency, and also because
2852 some broken systems expect each response to be in a single packet, arrange
2853 that the entire reply is sent in one write(). */
2854
2855 auth_advertised = FALSE;
2856 pipelining_advertised = FALSE;
2857 #ifdef SUPPORT_TLS
2858 tls_advertised = FALSE;
2859 #endif
2860
2861 smtp_code = US"250 "; /* Default response code plus space*/
2862 if (user_msg == NULL)
2863 {
2864 s = string_sprintf("%.3s %s Hello %s%s%s",
2865 smtp_code,
2866 smtp_active_hostname,
2867 (sender_ident == NULL)? US"" : sender_ident,
2868 (sender_ident == NULL)? US"" : US" at ",
2869 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2870
2871 ptr = Ustrlen(s);
2872 size = ptr + 1;
2873
2874 if (sender_host_address != NULL)
2875 {
2876 s = string_cat(s, &size, &ptr, US" [", 2);
2877 s = string_cat(s, &size, &ptr, sender_host_address,
2878 Ustrlen(sender_host_address));
2879 s = string_cat(s, &size, &ptr, US"]", 1);
2880 }
2881 }
2882
2883 /* A user-supplied EHLO greeting may not contain more than one line. Note
2884 that the code returned by smtp_message_code() includes the terminating
2885 whitespace character. */
2886
2887 else
2888 {
2889 char *ss;
2890 int codelen = 4;
2891 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
2892 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
2893 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
2894 {
2895 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
2896 "newlines: message truncated: %s", string_printing(s));
2897 *ss = 0;
2898 }
2899 ptr = Ustrlen(s);
2900 size = ptr + 1;
2901 }
2902
2903 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2904
2905 /* If we received EHLO, we must create a multiline response which includes
2906 the functions supported. */
2907
2908 if (esmtp)
2909 {
2910 s[3] = '-';
2911
2912 /* I'm not entirely happy with this, as an MTA is supposed to check
2913 that it has enough room to accept a message of maximum size before
2914 it sends this. However, there seems little point in not sending it.
2915 The actual size check happens later at MAIL FROM time. By postponing it
2916 till then, VRFY and EXPN can be used after EHLO when space is short. */
2917
2918 if (thismessage_size_limit > 0)
2919 {
2920 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
2921 thismessage_size_limit);
2922 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2923 }
2924 else
2925 {
2926 s = string_cat(s, &size, &ptr, smtp_code, 3);
2927 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
2928 }
2929
2930 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2931 clean; if it has an 8-bit character in its hand, it just sends it. It
2932 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2933 However, some users want this option simply in order to stop MUAs
2934 mangling messages that contain top-bit-set characters. It is therefore
2935 provided as an option. */
2936
2937 if (accept_8bitmime)
2938 {
2939 s = string_cat(s, &size, &ptr, smtp_code, 3);
2940 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
2941 }
2942
2943 /* Advertise ETRN if there's an ACL checking whether a host is
2944 permitted to issue it; a check is made when any host actually tries. */
2945
2946 if (acl_smtp_etrn != NULL)
2947 {
2948 s = string_cat(s, &size, &ptr, smtp_code, 3);
2949 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
2950 }
2951
2952 /* Advertise EXPN if there's an ACL checking whether a host is
2953 permitted to issue it; a check is made when any host actually tries. */
2954
2955 if (acl_smtp_expn != NULL)
2956 {
2957 s = string_cat(s, &size, &ptr, smtp_code, 3);
2958 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
2959 }
2960
2961 /* Exim is quite happy with pipelining, so let the other end know that
2962 it is safe to use it, unless advertising is disabled. */
2963
2964 if (pipelining_enable &&
2965 verify_check_host(&pipelining_advertise_hosts) == OK)
2966 {
2967 s = string_cat(s, &size, &ptr, smtp_code, 3);
2968 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
2969 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2970 pipelining_advertised = TRUE;
2971 }
2972
2973 /* If any server authentication mechanisms are configured, advertise
2974 them if the current host is in auth_advertise_hosts. The problem with
2975 advertising always is that some clients then require users to
2976 authenticate (and aren't configurable otherwise) even though it may not
2977 be necessary (e.g. if the host is in host_accept_relay).
2978
2979 RFC 2222 states that SASL mechanism names contain only upper case
2980 letters, so output the names in upper case, though we actually recognize
2981 them in either case in the AUTH command. */
2982
2983 if (auths != NULL)
2984 {
2985 if (verify_check_host(&auth_advertise_hosts) == OK)
2986 {
2987 auth_instance *au;
2988 BOOL first = TRUE;
2989 for (au = auths; au != NULL; au = au->next)
2990 {
2991 if (au->server && (au->advertise_condition == NULL ||
2992 expand_check_condition(au->advertise_condition, au->name,
2993 US"authenticator")))
2994 {
2995 int saveptr;
2996 if (first)
2997 {
2998 s = string_cat(s, &size, &ptr, smtp_code, 3);
2999 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3000 first = FALSE;
3001 auth_advertised = TRUE;
3002 }
3003 saveptr = ptr;
3004 s = string_cat(s, &size, &ptr, US" ", 1);
3005 s = string_cat(s, &size, &ptr, au->public_name,
3006 Ustrlen(au->public_name));
3007 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3008 au->advertised = TRUE;
3009 }
3010 else au->advertised = FALSE;
3011 }
3012 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3013 }
3014 }
3015
3016 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3017 if it has been included in the binary, and the host matches
3018 tls_advertise_hosts. We must *not* advertise if we are already in a
3019 secure connection. */
3020
3021 #ifdef SUPPORT_TLS
3022 if (tls_active < 0 &&
3023 verify_check_host(&tls_advertise_hosts) != FAIL)
3024 {
3025 s = string_cat(s, &size, &ptr, smtp_code, 3);
3026 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3027 tls_advertised = TRUE;
3028 }
3029 #endif
3030
3031 /* Finish off the multiline reply with one that is always available. */
3032
3033 s = string_cat(s, &size, &ptr, smtp_code, 3);
3034 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3035 }
3036
3037 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3038 has been seen. */
3039
3040 s[ptr] = 0;
3041
3042 #ifdef SUPPORT_TLS
3043 if (tls_active >= 0) (void)tls_write(s, ptr); else
3044 #endif
3045
3046 (void)fwrite(s, 1, ptr, smtp_out);
3047 DEBUG(D_receive)
3048 {
3049 uschar *cr;
3050 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3051 memmove(cr, cr + 1, (ptr--) - (cr - s));
3052 debug_printf("SMTP>> %s", s);
3053 }
3054 helo_seen = TRUE;
3055
3056 /* Reset the protocol and the state, abandoning any previous message. */
3057
3058 received_protocol = (esmtp?
3059 protocols[pextend +
3060 ((sender_host_authenticated != NULL)? pauthed : 0) +
3061 ((tls_active >= 0)? pcrpted : 0)]
3062 :
3063 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
3064 +
3065 ((sender_host_address != NULL)? pnlocal : 0);
3066
3067 smtp_reset(reset_point);
3068 toomany = FALSE;
3069 break; /* HELO/EHLO */
3070
3071
3072 /* The MAIL command requires an address as an operand. All we do
3073 here is to parse it for syntactic correctness. The form "<>" is
3074 a special case which converts into an empty string. The start/end
3075 pointers in the original are not used further for this address, as
3076 it is the canonical extracted address which is all that is kept. */
3077
3078 case MAIL_CMD:
3079 HAD(SCH_MAIL);
3080 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3081 was_rej_mail = TRUE; /* Reset if accepted */
3082
3083 if (helo_required && !helo_seen)
3084 {
3085 smtp_printf("503 HELO or EHLO required\r\n");
3086 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3087 "HELO/EHLO given", host_and_ident(FALSE));
3088 break;
3089 }
3090
3091 if (sender_address != NULL)
3092 {
3093 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3094 US"sender already given");
3095 break;
3096 }
3097
3098 if (smtp_cmd_data[0] == 0)
3099 {
3100 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3101 US"MAIL must have an address operand");
3102 break;
3103 }
3104
3105 /* Check to see if the limit for messages per connection would be
3106 exceeded by accepting further messages. */
3107
3108 if (smtp_accept_max_per_connection > 0 &&
3109 smtp_mailcmd_count > smtp_accept_max_per_connection)
3110 {
3111 smtp_printf("421 too many messages in this connection\r\n");
3112 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3113 "messages in one connection", host_and_ident(TRUE));
3114 break;
3115 }
3116
3117 /* Reset for start of message - even if this is going to fail, we
3118 obviously need to throw away any previous data. */
3119
3120 smtp_reset(reset_point);
3121 toomany = FALSE;
3122 sender_data = recipient_data = NULL;
3123
3124 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3125
3126 if (esmtp) for(;;)
3127 {
3128 uschar *name, *value, *end;
3129 unsigned long int size;
3130
3131 if (!extract_option(&name, &value)) break;
3132
3133 /* Handle SIZE= by reading the value. We don't do the check till later,
3134 in order to be able to log the sender address on failure. */
3135
3136 if (strcmpic(name, US"SIZE") == 0 &&
3137 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
3138 {
3139 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3140 size = INT_MAX;
3141 message_size = (int)size;
3142 }
3143
3144 /* If this session was initiated with EHLO and accept_8bitmime is set,
3145 Exim will have indicated that it supports the BODY=8BITMIME option. In
3146 fact, it does not support this according to the RFCs, in that it does not
3147 take any special action for forwarding messages containing 8-bit
3148 characters. That is why accept_8bitmime is not the default setting, but
3149 some sites want the action that is provided. We recognize both "8BITMIME"
3150 and "7BIT" as body types, but take no action. */
3151
3152 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
3153 (strcmpic(value, US"8BITMIME") == 0 ||
3154 strcmpic(value, US"7BIT") == 0)) {}
3155
3156 /* Handle the AUTH extension. If the value given is not "<>" and either
3157 the ACL says "yes" or there is no ACL but the sending host is
3158 authenticated, we set it up as the authenticated sender. However, if the
3159 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3160 the condition is met. The value of AUTH is an xtext, which means that +,
3161 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3162 coding. */
3163
3164 else if (strcmpic(name, US"AUTH") == 0)
3165 {
3166 if (Ustrcmp(value, "<>") != 0)
3167 {
3168 int rc;
3169 uschar *ignore_msg;
3170
3171 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3172 {
3173 /* Put back terminator overrides for error message */
3174 name[-1] = ' ';
3175 value[-1] = '=';
3176 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3177 US"invalid data for AUTH");
3178 goto COMMAND_LOOP;
3179 }
3180
3181 if (acl_smtp_mailauth == NULL)
3182 {
3183 ignore_msg = US"client not authenticated";
3184 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3185 }
3186 else
3187 {
3188 ignore_msg = US"rejected by ACL";
3189 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3190 &user_msg, &log_msg);
3191 }
3192
3193 switch (rc)
3194 {
3195 case OK:
3196 if (authenticated_by == NULL ||
3197 authenticated_by->mail_auth_condition == NULL ||
3198 expand_check_condition(authenticated_by->mail_auth_condition,
3199 authenticated_by->name, US"authenticator"))
3200 break; /* Accept the AUTH */
3201
3202 ignore_msg = US"server_mail_auth_condition failed";
3203 if (authenticated_id != NULL)
3204 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3205 ignore_msg, authenticated_id);
3206
3207 /* Fall through */
3208
3209 case FAIL:
3210 authenticated_sender = NULL;
3211 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3212 value, host_and_ident(TRUE), ignore_msg);
3213 break;
3214
3215 /* Should only get DEFER or ERROR here. Put back terminator
3216 overrides for error message */
3217
3218 default:
3219 name[-1] = ' ';
3220 value[-1] = '=';
3221 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3222 log_msg);
3223 goto COMMAND_LOOP;
3224 }
3225 }
3226 }
3227
3228 /* Unknown option. Stick back the terminator characters and break
3229 the loop. An error for a malformed address will occur. */
3230
3231 else
3232 {
3233 name[-1] = ' ';
3234 value[-1] = '=';
3235 break;
3236 }
3237 }
3238
3239 /* If we have passed the threshold for rate limiting, apply the current
3240 delay, and update it for next time, provided this is a limited host. */
3241
3242 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3243 verify_check_host(&smtp_ratelimit_hosts) == OK)
3244 {
3245 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3246 smtp_delay_mail/1000.0);
3247 millisleep((int)smtp_delay_mail);
3248 smtp_delay_mail *= smtp_rlm_factor;
3249 if (smtp_delay_mail > (double)smtp_rlm_limit)
3250 smtp_delay_mail = (double)smtp_rlm_limit;
3251 }
3252
3253 /* Now extract the address, first applying any SMTP-time rewriting. The
3254 TRUE flag allows "<>" as a sender address. */
3255
3256 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3257 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3258 global_rewrite_rules) : smtp_cmd_data;
3259
3260 /* rfc821_domains = TRUE; << no longer needed */
3261 raw_sender =
3262 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3263 TRUE);
3264 /* rfc821_domains = FALSE; << no longer needed */
3265
3266 if (raw_sender == NULL)
3267 {
3268 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3269 break;
3270 }
3271
3272 sender_address = raw_sender;
3273
3274 /* If there is a configured size limit for mail, check that this message
3275 doesn't exceed it. The check is postponed to this point so that the sender
3276 can be logged. */
3277
3278 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3279 {
3280 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3281 log_write(L_size_reject,
3282 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3283 "message too big: size%s=%d max=%d",
3284 sender_address,
3285 host_and_ident(TRUE),
3286 (message_size == INT_MAX)? ">" : "",
3287 message_size,
3288 thismessage_size_limit);
3289 sender_address = NULL;
3290 break;
3291 }
3292
3293 /* Check there is enough space on the disk unless configured not to.
3294 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3295 plus the current message - i.e. we accept the message only if it won't
3296 reduce the space below the threshold. Add 5000 to the size to allow for
3297 overheads such as the Received: line and storing of recipients, etc.
3298 By putting the check here, even when SIZE is not given, it allow VRFY
3299 and EXPN etc. to be used when space is short. */
3300
3301 if (!receive_check_fs(
3302 (smtp_check_spool_space && message_size >= 0)?
3303 message_size + 5000 : 0))
3304 {
3305 smtp_printf("452 Space shortage, please try later\r\n");
3306 sender_address = NULL;
3307 break;
3308 }
3309
3310 /* If sender_address is unqualified, reject it, unless this is a locally
3311 generated message, or the sending host or net is permitted to send
3312 unqualified addresses - typically local machines behaving as MUAs -
3313 in which case just qualify the address. The flag is set above at the start
3314 of the SMTP connection. */
3315
3316 if (sender_domain == 0 && sender_address[0] != 0)
3317 {
3318 if (allow_unqualified_sender)
3319 {
3320 sender_domain = Ustrlen(sender_address) + 1;
3321 sender_address = rewrite_address_qualify(sender_address, FALSE);
3322 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3323 raw_sender);
3324 }
3325 else
3326 {
3327 smtp_printf("501 %s: sender address must contain a domain\r\n",
3328 smtp_cmd_data);
3329 log_write(L_smtp_syntax_error,
3330 LOG_MAIN|LOG_REJECT,
3331 "unqualified sender rejected: <%s> %s%s",
3332 raw_sender,
3333 host_and_ident(TRUE),
3334 host_lookup_msg);
3335 sender_address = NULL;
3336 break;
3337 }
3338 }
3339
3340 /* Apply an ACL check if one is defined, before responding. Afterwards,
3341 when pipelining is not advertised, do another sync check in case the ACL
3342 delayed and the client started sending in the meantime. */
3343
3344 if (acl_smtp_mail == NULL) rc = OK; else
3345 {
3346 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3347 if (rc == OK && !pipelining_advertised && !check_sync())
3348 goto SYNC_FAILURE;
3349 }
3350
3351 if (rc == OK || rc == DISCARD)
3352 {
3353 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3354 else smtp_user_msg(US"250", user_msg);
3355 smtp_delay_rcpt = smtp_rlr_base;
3356 recipients_discarded = (rc == DISCARD);
3357 was_rej_mail = FALSE;
3358 }
3359 else
3360 {
3361 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3362 sender_address = NULL;
3363 }
3364 break;
3365
3366
3367 /* The RCPT command requires an address as an operand. There may be any
3368 number of RCPT commands, specifying multiple recipients. We build them all
3369 into a data structure. The start/end values given by parse_extract_address
3370 are not used, as we keep only the extracted address. */
3371
3372 case RCPT_CMD:
3373 HAD(SCH_RCPT);
3374 rcpt_count++;
3375 was_rcpt = rcpt_in_progress = TRUE;
3376
3377 /* There must be a sender address; if the sender was rejected and
3378 pipelining was advertised, we assume the client was pipelining, and do not
3379 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3380 get the same treatment. */
3381
3382 if (sender_address == NULL)
3383 {
3384 if (pipelining_advertised && last_was_rej_mail)
3385 {
3386 smtp_printf("503 sender not yet given\r\n");
3387 was_rej_mail = TRUE;
3388 }
3389 else
3390 {
3391 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3392 US"sender not yet given");
3393 was_rcpt = FALSE; /* Not a valid RCPT */
3394 }
3395 rcpt_fail_count++;
3396 break;
3397 }
3398
3399 /* Check for an operand */
3400
3401 if (smtp_cmd_data[0] == 0)
3402 {
3403 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3404 US"RCPT must have an address operand");
3405 rcpt_fail_count++;
3406 break;
3407 }
3408
3409 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3410 as a recipient address */
3411
3412 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3413 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3414 global_rewrite_rules) : smtp_cmd_data;
3415
3416 /* rfc821_domains = TRUE; << no longer needed */
3417 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3418 &recipient_domain, FALSE);
3419 /* rfc821_domains = FALSE; << no longer needed */
3420
3421 if (recipient == NULL)
3422 {
3423 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3424 rcpt_fail_count++;
3425 break;
3426 }
3427
3428 /* If the recipient address is unqualified, reject it, unless this is a
3429 locally generated message. However, unqualified addresses are permitted
3430 from a configured list of hosts and nets - typically when behaving as
3431 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3432 really. The flag is set at the start of the SMTP connection.
3433
3434 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3435 assumed this meant "reserved local part", but the revision of RFC 821 and
3436 friends now makes it absolutely clear that it means *mailbox*. Consequently
3437 we must always qualify this address, regardless. */
3438
3439 if (recipient_domain == 0)
3440 {
3441 if (allow_unqualified_recipient ||
3442 strcmpic(recipient, US"postmaster") == 0)
3443 {
3444 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3445 recipient);
3446 recipient_domain = Ustrlen(recipient) + 1;
3447 recipient = rewrite_address_qualify(recipient, TRUE);
3448 }
3449 else
3450 {
3451 rcpt_fail_count++;
3452 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3453 smtp_cmd_data);
3454 log_write(L_smtp_syntax_error,
3455 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3456 "<%s> %s%s", recipient, host_and_ident(TRUE),
3457 host_lookup_msg);
3458 break;
3459 }
3460 }
3461
3462 /* Check maximum allowed */
3463
3464 if (rcpt_count > recipients_max && recipients_max > 0)
3465 {
3466 if (recipients_max_reject)
3467 {
3468 rcpt_fail_count++;
3469 smtp_printf("552 too many recipients\r\n");
3470 if (!toomany)
3471 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3472 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3473 }
3474 else
3475 {
3476 rcpt_defer_count++;
3477 smtp_printf("452 too many recipients\r\n");
3478 if (!toomany)
3479 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3480 "temporarily rejected: sender=<%s> %s", sender_address,
3481 host_and_ident(TRUE));
3482 }
3483
3484 toomany = TRUE;
3485 break;
3486 }
3487
3488 /* If we have passed the threshold for rate limiting, apply the current
3489 delay, and update it for next time, provided this is a limited host. */
3490
3491 if (rcpt_count > smtp_rlr_threshold &&
3492 verify_check_host(&smtp_ratelimit_hosts) == OK)
3493 {
3494 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3495 smtp_delay_rcpt/1000.0);
3496 millisleep((int)smtp_delay_rcpt);
3497 smtp_delay_rcpt *= smtp_rlr_factor;
3498 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3499 smtp_delay_rcpt = (double)smtp_rlr_limit;
3500 }
3501
3502 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking