Minor changes for the test harness.
[exim.git] / src / src / smtp_in.c
1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.28 2005/12/14 10:00:05 ph10 Exp $ */
2
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
6
7 /* Copyright (c) University of Cambridge 1995 - 2005 */
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
100 /*************************************************
101 * Local static variables *
102 *************************************************/
103
104 static auth_instance *authenticated_by;
105 static BOOL auth_advertised;
106 #ifdef SUPPORT_TLS
107 static BOOL tls_advertised;
108 #endif
109 static BOOL esmtp;
110 static BOOL helo_required = FALSE;
111 static BOOL helo_verify = FALSE;
112 static BOOL helo_seen;
113 static BOOL helo_accept_junk;
114 static BOOL count_nonmail;
115 static BOOL pipelining_advertised;
116 static int nonmail_command_count;
117 static int synprot_error_count;
118 static int unknown_command_count;
119 static int sync_cmd_limit;
120 static int smtp_write_error = 0;
121
122 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
123 final fields of all except AUTH are forced TRUE at the start of a new message
124 setup, to allow one of each between messages that is not counted as a nonmail
125 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
126 allow a new EHLO after starting up TLS.
127
128 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
129 counted. However, the flag is changed when AUTH is received, so that multiple
130 failing AUTHs will eventually hit the limit. After a successful AUTH, another
131 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
132 forced TRUE, to allow for the re-authentication that can happen at that point.
133
134 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
135 count of non-mail commands and possibly provoke an error. */
136
137 static smtp_cmd_list cmd_list[] = {
138 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
139 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
140 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
141 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
142 #ifdef SUPPORT_TLS
143 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
144 #endif
145
146 /* If you change anything above here, also fix the definitions below. */
147
148 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
149 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
150 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
151 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
152 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
153 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
154 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
155 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
156 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
157 };
158
159 static smtp_cmd_list *cmd_list_end =
160 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
161
162 #define CMD_LIST_RSET 0
163 #define CMD_LIST_HELO 1
164 #define CMD_LIST_EHLO 2
165 #define CMD_LIST_AUTH 3
166 #define CMD_LIST_STARTTLS 4
167
168 static uschar *protocols[] = {
169 US"local-smtp", /* HELO */
170 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
171 US"local-esmtp", /* EHLO */
172 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
173 US"local-esmtpa", /* EHLO->AUTH */
174 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
175 };
176
177 #define pnormal 0
178 #define pextend 2
179 #define pcrpted 1 /* added to pextend or pnormal */
180 #define pauthed 2 /* added to pextend */
181 #define pnlocal 6 /* offset to remove "local" */
182
183 /* When reading SMTP from a remote host, we have to use our own versions of the
184 C input-reading functions, in order to be able to flush the SMTP output only
185 when about to read more data from the socket. This is the only way to get
186 optimal performance when the client is using pipelining. Flushing for every
187 command causes a separate packet and reply packet each time; saving all the
188 responses up (when pipelining) combines them into one packet and one response.
189
190 For simplicity, these functions are used for *all* SMTP input, not only when
191 receiving over a socket. However, after setting up a secure socket (SSL), input
192 is read via the OpenSSL library, and another set of functions is used instead
193 (see tls.c).
194
195 These functions are set in the receive_getc etc. variables and called with the
196 same interface as the C functions. However, since there can only ever be
197 one incoming SMTP call, we just use a single buffer and flags. There is no need
198 to implement a complicated private FILE-like structure.*/
199
200 static uschar *smtp_inbuffer;
201 static uschar *smtp_inptr;
202 static uschar *smtp_inend;
203 static int smtp_had_eof;
204 static int smtp_had_error;
205
206
207 /*************************************************
208 * SMTP version of getc() *
209 *************************************************/
210
211 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
212 it flushes the output, and refills the buffer, with a timeout. The signal
213 handler is set appropriately by the calling function. This function is not used
214 after a connection has negotated itself into an TLS/SSL state.
215
216 Arguments: none
217 Returns: the next character or EOF
218 */
219
220 int
221 smtp_getc(void)
222 {
223 if (smtp_inptr >= smtp_inend)
224 {
225 int rc, save_errno;
226 fflush(smtp_out);
227 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
228 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
229 save_errno = errno;
230 alarm(0);
231 if (rc <= 0)
232 {
233 /* Must put the error text in fixed store, because this might be during
234 header reading, where it releases unused store above the header. */
235 if (rc < 0)
236 {
237 smtp_had_error = save_errno;
238 smtp_read_error = string_copy_malloc(
239 string_sprintf(" (error: %s)", strerror(save_errno)));
240 }
241 else smtp_had_eof = 1;
242 return EOF;
243 }
244 smtp_inend = smtp_inbuffer + rc;
245 smtp_inptr = smtp_inbuffer;
246 }
247 return *smtp_inptr++;
248 }
249
250
251
252 /*************************************************
253 * SMTP version of ungetc() *
254 *************************************************/
255
256 /* Puts a character back in the input buffer. Only ever
257 called once.
258
259 Arguments:
260 ch the character
261
262 Returns: the character
263 */
264
265 int
266 smtp_ungetc(int ch)
267 {
268 *(--smtp_inptr) = ch;
269 return ch;
270 }
271
272
273
274
275 /*************************************************
276 * SMTP version of feof() *
277 *************************************************/
278
279 /* Tests for a previous EOF
280
281 Arguments: none
282 Returns: non-zero if the eof flag is set
283 */
284
285 int
286 smtp_feof(void)
287 {
288 return smtp_had_eof;
289 }
290
291
292
293
294 /*************************************************
295 * SMTP version of ferror() *
296 *************************************************/
297
298 /* Tests for a previous read error, and returns with errno
299 restored to what it was when the error was detected.
300
301 Arguments: none
302 Returns: non-zero if the error flag is set
303 */
304
305 int
306 smtp_ferror(void)
307 {
308 errno = smtp_had_error;
309 return smtp_had_error;
310 }
311
312
313
314
315 /*************************************************
316 * Write formatted string to SMTP channel *
317 *************************************************/
318
319 /* This is a separate function so that we don't have to repeat everything for
320 TLS support or debugging. It is global so that the daemon and the
321 authentication functions can use it. It does not return any error indication,
322 because major problems such as dropped connections won't show up till an output
323 flush for non-TLS connections. The smtp_fflush() function is available for
324 checking that: for convenience, TLS output errors are remembered here so that
325 they are also picked up later by smtp_fflush().
326
327 Arguments:
328 format format string
329 ... optional arguments
330
331 Returns: nothing
332 */
333
334 void
335 smtp_printf(char *format, ...)
336 {
337 va_list ap;
338
339 DEBUG(D_receive)
340 {
341 va_start(ap, format);
342 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
343 debug_printf("SMTP>> %s", big_buffer);
344 }
345
346 va_start(ap, format);
347
348 /* If in a TLS session we have to format the string, and then write it using a
349 TLS function. */
350
351 #ifdef SUPPORT_TLS
352 if (tls_active >= 0)
353 {
354 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
355 {
356 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
357 smtp_closedown(US"Unexpected error");
358 exim_exit(EXIT_FAILURE);
359 }
360 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
361 }
362 else
363 #endif
364
365 /* Otherwise, just use the standard library function. */
366
367 if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
368 va_end(ap);
369 }
370
371
372
373 /*************************************************
374 * Flush SMTP out and check for error *
375 *************************************************/
376
377 /* This function isn't currently used within Exim (it detects errors when it
378 tries to read the next SMTP input), but is available for use in local_scan().
379 For non-TLS connections, it flushes the output and checks for errors. For
380 TLS-connections, it checks for a previously-detected TLS write error.
381
382 Arguments: none
383 Returns: 0 for no error; -1 after an error
384 */
385
386 int
387 smtp_fflush(void)
388 {
389 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
390 return smtp_write_error;
391 }
392
393
394
395 /*************************************************
396 * SMTP command read timeout *
397 *************************************************/
398
399 /* Signal handler for timing out incoming SMTP commands. This attempts to
400 finish off tidily.
401
402 Argument: signal number (SIGALRM)
403 Returns: nothing
404 */
405
406 static void
407 command_timeout_handler(int sig)
408 {
409 sig = sig; /* Keep picky compilers happy */
410 log_write(L_lost_incoming_connection,
411 LOG_MAIN, "SMTP command timeout on%s connection from %s",
412 (tls_active >= 0)? " TLS" : "",
413 host_and_ident(FALSE));
414 if (smtp_batched_input)
415 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
416 smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
417 smtp_active_hostname);
418 mac_smtp_fflush();
419 exim_exit(EXIT_FAILURE);
420 }
421
422
423
424 /*************************************************
425 * SIGTERM received *
426 *************************************************/
427
428 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
429
430 Argument: signal number (SIGTERM)
431 Returns: nothing
432 */
433
434 static void
435 command_sigterm_handler(int sig)
436 {
437 sig = sig; /* Keep picky compilers happy */
438 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
439 if (smtp_batched_input)
440 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
441 smtp_printf("421 %s: Service not available - closing connection\r\n",
442 smtp_active_hostname);
443 exim_exit(EXIT_FAILURE);
444 }
445
446
447
448 /*************************************************
449 * Read one command line *
450 *************************************************/
451
452 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
453 There are sites that don't do this, and in any case internal SMTP probably
454 should check only for LF. Consequently, we check here for LF only. The line
455 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
456 an unknown command. The command is read into the global smtp_cmd_buffer so that
457 it is available via $smtp_command.
458
459 The character reading routine sets up a timeout for each block actually read
460 from the input (which may contain more than one command). We set up a special
461 signal handler that closes down the session on a timeout. Control does not
462 return when it runs.
463
464 Arguments:
465 check_sync if TRUE, check synchronization rules if global option is TRUE
466
467 Returns: a code identifying the command (enumerated above)
468 */
469
470 static int
471 smtp_read_command(BOOL check_sync)
472 {
473 int c;
474 int ptr = 0;
475 smtp_cmd_list *p;
476 BOOL hadnull = FALSE;
477
478 os_non_restarting_signal(SIGALRM, command_timeout_handler);
479
480 while ((c = (receive_getc)()) != '\n' && c != EOF)
481 {
482 if (ptr >= smtp_cmd_buffer_size)
483 {
484 os_non_restarting_signal(SIGALRM, sigalrm_handler);
485 return OTHER_CMD;
486 }
487 if (c == 0)
488 {
489 hadnull = TRUE;
490 c = '?';
491 }
492 smtp_cmd_buffer[ptr++] = c;
493 }
494
495 receive_linecount++; /* For BSMTP errors */
496 os_non_restarting_signal(SIGALRM, sigalrm_handler);
497
498 /* If hit end of file, return pseudo EOF command. Whether we have a
499 part-line already read doesn't matter, since this is an error state. */
500
501 if (c == EOF) return EOF_CMD;
502
503 /* Remove any CR and white space at the end of the line, and terminate the
504 string. */
505
506 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
507 smtp_cmd_buffer[ptr] = 0;
508
509 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
510
511 /* NULLs are not allowed in SMTP commands */
512
513 if (hadnull) return BADCHAR_CMD;
514
515 /* Scan command list and return identity, having set the data pointer
516 to the start of the actual data characters. Check for SMTP synchronization
517 if required. */
518
519 for (p = cmd_list; p < cmd_list_end; p++)
520 {
521 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0)
522 {
523 if (smtp_inptr < smtp_inend && /* Outstanding input */
524 p->cmd < sync_cmd_limit && /* Command should sync */
525 check_sync && /* Local flag set */
526 smtp_enforce_sync && /* Global flag set */
527 sender_host_address != NULL && /* Not local input */
528 !sender_host_notsocket) /* Really is a socket */
529 return BADSYN_CMD;
530
531 /* Point after the command, but don't skip over leading spaces till after
532 the following test, so that if it fails, the command name can easily be
533 logged. */
534
535 smtp_cmd_argument = smtp_cmd_buffer + p->len;
536
537 /* Count non-mail commands from those hosts that are controlled in this
538 way. The default is all hosts. We don't waste effort checking the list
539 until we get a non-mail command, but then cache the result to save checking
540 again. If there's a DEFER while checking the host, assume it's in the list.
541
542 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
543 start of each incoming message by fiddling with the value in the table. */
544
545 if (!p->is_mail_cmd)
546 {
547 if (count_nonmail == TRUE_UNSET) count_nonmail =
548 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
549 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
550 return TOO_MANY_NONMAIL_CMD;
551 }
552
553 /* Get the data pointer over leading spaces and return; if there is data
554 for a command that does not expect it, give the error centrally here. */
555
556 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
557 return (p->has_arg || *smtp_cmd_argument == 0)? p->cmd : BADARG_CMD;
558 }
559 }
560
561 /* Enforce synchronization for unknown commands */
562
563 if (smtp_inptr < smtp_inend && /* Outstanding input */
564 check_sync && /* Local flag set */
565 smtp_enforce_sync && /* Global flag set */
566 sender_host_address != NULL && /* Not local input */
567 !sender_host_notsocket) /* Really is a socket */
568 return BADSYN_CMD;
569
570 return OTHER_CMD;
571 }
572
573
574
575 /*************************************************
576 * Forced closedown of call *
577 *************************************************/
578
579 /* This function is called from log.c when Exim is dying because of a serious
580 disaster, and also from some other places. If an incoming non-batched SMTP
581 channel is open, it swallows the rest of the incoming message if in the DATA
582 phase, sends the reply string, and gives an error to all subsequent commands
583 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
584 smtp_in.
585
586 Argument: SMTP reply string to send, excluding the code
587 Returns: nothing
588 */
589
590 void
591 smtp_closedown(uschar *message)
592 {
593 if (smtp_in == NULL || smtp_batched_input) return;
594 receive_swallow_smtp();
595 smtp_printf("421 %s\r\n", message);
596
597 for (;;)
598 {
599 switch(smtp_read_command(FALSE))
600 {
601 case EOF_CMD:
602 return;
603
604 case QUIT_CMD:
605 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
606 mac_smtp_fflush();
607 return;
608
609 case RSET_CMD:
610 smtp_printf("250 Reset OK\r\n");
611 break;
612
613 default:
614 smtp_printf("421 %s\r\n", message);
615 break;
616 }
617 }
618 }
619
620
621
622
623 /*************************************************
624 * Set up connection info for logging *
625 *************************************************/
626
627 /* This function is called when logging information about an SMTP connection.
628 It sets up appropriate source information, depending on the type of connection.
629
630 Argument: none
631 Returns: a string describing the connection
632 */
633
634 uschar *
635 smtp_get_connection_info(void)
636 {
637 if (host_checking)
638 return string_sprintf("SMTP connection from %s", sender_fullhost);
639
640 if (sender_host_unknown || sender_host_notsocket)
641 return string_sprintf("SMTP connection from %s", sender_ident);
642
643 if (is_inetd)
644 return string_sprintf("SMTP connection from %s (via inetd)", sender_fullhost);
645
646 if ((log_extra_selector & LX_incoming_interface) != 0 &&
647 interface_address != NULL)
648 return string_sprintf("SMTP connection from %s I=[%s]:%d", sender_fullhost,
649 interface_address, interface_port);
650
651 return string_sprintf("SMTP connection from %s", sender_fullhost);
652 }
653
654
655
656 /*************************************************
657 * Check HELO line and set sender_helo_name *
658 *************************************************/
659
660 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
661 the domain name of the sending host, or an ip literal in square brackets. The
662 arrgument is placed in sender_helo_name, which is in malloc store, because it
663 must persist over multiple incoming messages. If helo_accept_junk is set, this
664 host is permitted to send any old junk (needed for some broken hosts).
665 Otherwise, helo_allow_chars can be used for rogue characters in general
666 (typically people want to let in underscores).
667
668 Argument:
669 s the data portion of the line (already past any white space)
670
671 Returns: TRUE or FALSE
672 */
673
674 static BOOL
675 check_helo(uschar *s)
676 {
677 uschar *start = s;
678 uschar *end = s + Ustrlen(s);
679 BOOL yield = helo_accept_junk;
680
681 /* Discard any previous helo name */
682
683 if (sender_helo_name != NULL)
684 {
685 store_free(sender_helo_name);
686 sender_helo_name = NULL;
687 }
688
689 /* Skip tests if junk is permitted. */
690
691 if (!yield)
692 {
693 /* Allow the new standard form for IPv6 address literals, namely,
694 [IPv6:....], and because someone is bound to use it, allow an equivalent
695 IPv4 form. Allow plain addresses as well. */
696
697 if (*s == '[')
698 {
699 if (end[-1] == ']')
700 {
701 end[-1] = 0;
702 if (strncmpic(s, US"[IPv6:", 6) == 0)
703 yield = (string_is_ip_address(s+6, NULL) == 6);
704 else if (strncmpic(s, US"[IPv4:", 6) == 0)
705 yield = (string_is_ip_address(s+6, NULL) == 4);
706 else
707 yield = (string_is_ip_address(s+1, NULL) != 0);
708 end[-1] = ']';
709 }
710 }
711
712 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
713 that have been configured (usually underscore - sigh). */
714
715 else if (*s != 0)
716 {
717 yield = TRUE;
718 while (*s != 0)
719 {
720 if (!isalnum(*s) && *s != '.' && *s != '-' &&
721 Ustrchr(helo_allow_chars, *s) == NULL)
722 {
723 yield = FALSE;
724 break;
725 }
726 s++;
727 }
728 }
729 }
730
731 /* Save argument if OK */
732
733 if (yield) sender_helo_name = string_copy_malloc(start);
734 return yield;
735 }
736
737
738
739
740
741 /*************************************************
742 * Extract SMTP command option *
743 *************************************************/
744
745 /* This function picks the next option setting off the end of smtp_cmd_argument. It
746 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
747 things that can appear there.
748
749 Arguments:
750 name point this at the name
751 value point this at the data string
752
753 Returns: TRUE if found an option
754 */
755
756 static BOOL
757 extract_option(uschar **name, uschar **value)
758 {
759 uschar *n;
760 uschar *v = smtp_cmd_argument + Ustrlen(smtp_cmd_argument) -1;
761 while (isspace(*v)) v--;
762 v[1] = 0;
763
764 while (v > smtp_cmd_argument && *v != '=' && !isspace(*v)) v--;
765 if (*v != '=') return FALSE;
766
767 n = v;
768 while(isalpha(n[-1])) n--;
769
770 if (n[-1] != ' ') return FALSE;
771
772 n[-1] = 0;
773 *name = n;
774 *v++ = 0;
775 *value = v;
776 return TRUE;
777 }
778
779
780
781
782
783
784
785 /*************************************************
786 * Reset for new message *
787 *************************************************/
788
789 /* This function is called whenever the SMTP session is reset from
790 within either of the setup functions.
791
792 Argument: the stacking pool storage reset point
793 Returns: nothing
794 */
795
796 static void
797 smtp_reset(void *reset_point)
798 {
799 int i;
800 store_reset(reset_point);
801 recipients_list = NULL;
802 rcpt_count = rcpt_defer_count = rcpt_fail_count =
803 raw_recipients_count = recipients_count = recipients_list_max = 0;
804 message_linecount = 0;
805 message_size = -1;
806 acl_warn_headers = NULL;
807 queue_only_policy = FALSE;
808 deliver_freeze = FALSE; /* Can be set by ACL */
809 fake_response = OK; /* Can be set by ACL */
810 #ifdef WITH_CONTENT_SCAN
811 no_mbox_unspool = FALSE; /* Can be set by ACL */
812 #endif
813 submission_mode = FALSE; /* Can be set by ACL */
814 suppress_local_fixups = FALSE; /* Can be set by ACL */
815 active_local_from_check = local_from_check; /* Can be set by ACL */
816 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
817 sender_address = NULL;
818 submission_name = NULL; /* Can be set by ACL */
819 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
820 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
821 sender_verified_list = NULL; /* No senders verified */
822 memset(sender_address_cache, 0, sizeof(sender_address_cache));
823 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
824 authenticated_sender = NULL;
825 #ifdef EXPERIMENTAL_BRIGHTMAIL
826 bmi_run = 0;
827 bmi_verdicts = NULL;
828 #endif
829 #ifdef EXPERIMENTAL_DOMAINKEYS
830 dk_do_verify = 0;
831 #endif
832 #ifdef EXPERIMENTAL_SPF
833 spf_header_comment = NULL;
834 spf_received = NULL;
835 spf_result = NULL;
836 spf_smtp_comment = NULL;
837 #endif
838 body_linecount = body_zerocount = 0;
839
840 sender_rate = sender_rate_limit = sender_rate_period = NULL;
841 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
842 /* Note that ratelimiters_conn persists across resets. */
843
844 /* The message variables follow the connection variables. */
845
846 for (i = 0; i < ACL_MVARS; i++) acl_var[ACL_CVARS + i] = NULL;
847
848 /* The message body variables use malloc store. They may be set if this is
849 not the first message in an SMTP session and the previous message caused them
850 to be referenced in an ACL. */
851
852 if (message_body != NULL)
853 {
854 store_free(message_body);
855 message_body = NULL;
856 }
857
858 if (message_body_end != NULL)
859 {
860 store_free(message_body_end);
861 message_body_end = NULL;
862 }
863
864 /* Warning log messages are also saved in malloc store. They are saved to avoid
865 repetition in the same message, but it seems right to repeat them for different
866 messagess. */
867
868 while (acl_warn_logged != NULL)
869 {
870 string_item *this = acl_warn_logged;
871 acl_warn_logged = acl_warn_logged->next;
872 store_free(this);
873 }
874 }
875
876
877
878
879
880 /*************************************************
881 * Initialize for incoming batched SMTP message *
882 *************************************************/
883
884 /* This function is called from smtp_setup_msg() in the case when
885 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
886 of messages in one file with SMTP commands between them. All errors must be
887 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
888 relevant. After an error on a sender, or an invalid recipient, the remainder
889 of the message is skipped. The value of received_protocol is already set.
890
891 Argument: none
892 Returns: > 0 message successfully started (reached DATA)
893 = 0 QUIT read or end of file reached
894 < 0 should not occur
895 */
896
897 static int
898 smtp_setup_batch_msg(void)
899 {
900 int done = 0;
901 void *reset_point = store_get(0);
902
903 /* Save the line count at the start of each transaction - single commands
904 like HELO and RSET count as whole transactions. */
905
906 bsmtp_transaction_linecount = receive_linecount;
907
908 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
909
910 smtp_reset(reset_point); /* Reset for start of message */
911
912 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
913 value. The values are 2 larger than the required yield of the function. */
914
915 while (done <= 0)
916 {
917 uschar *errmess;
918 uschar *recipient = NULL;
919 int start, end, sender_domain, recipient_domain;
920
921 switch(smtp_read_command(FALSE))
922 {
923 /* The HELO/EHLO commands set sender_address_helo if they have
924 valid data; otherwise they are ignored, except that they do
925 a reset of the state. */
926
927 case HELO_CMD:
928 case EHLO_CMD:
929
930 check_helo(smtp_cmd_argument);
931 /* Fall through */
932
933 case RSET_CMD:
934 smtp_reset(reset_point);
935 bsmtp_transaction_linecount = receive_linecount;
936 break;
937
938
939 /* The MAIL FROM command requires an address as an operand. All we
940 do here is to parse it for syntactic correctness. The form "<>" is
941 a special case which converts into an empty string. The start/end
942 pointers in the original are not used further for this address, as
943 it is the canonical extracted address which is all that is kept. */
944
945 case MAIL_CMD:
946 if (sender_address != NULL)
947 /* The function moan_smtp_batch() does not return. */
948 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
949
950 if (smtp_cmd_argument[0] == 0)
951 /* The function moan_smtp_batch() does not return. */
952 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
953
954 /* Reset to start of message */
955
956 smtp_reset(reset_point);
957
958 /* Apply SMTP rewrite */
959
960 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
961 rewrite_one(smtp_cmd_argument, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
962 US"", global_rewrite_rules) : smtp_cmd_argument;
963
964 /* Extract the address; the TRUE flag allows <> as valid */
965
966 raw_sender =
967 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
968 TRUE);
969
970 if (raw_sender == NULL)
971 /* The function moan_smtp_batch() does not return. */
972 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
973
974 sender_address = string_copy(raw_sender);
975
976 /* Qualify unqualified sender addresses if permitted to do so. */
977
978 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
979 {
980 if (allow_unqualified_sender)
981 {
982 sender_address = rewrite_address_qualify(sender_address, FALSE);
983 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
984 "and rewritten\n", raw_sender);
985 }
986 /* The function moan_smtp_batch() does not return. */
987 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
988 "a domain");
989 }
990 break;
991
992
993 /* The RCPT TO command requires an address as an operand. All we do
994 here is to parse it for syntactic correctness. There may be any number
995 of RCPT TO commands, specifying multiple senders. We build them all into
996 a data structure that is in argc/argv format. The start/end values
997 given by parse_extract_address are not used, as we keep only the
998 extracted address. */
999
1000 case RCPT_CMD:
1001 if (sender_address == NULL)
1002 /* The function moan_smtp_batch() does not return. */
1003 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1004
1005 if (smtp_cmd_argument[0] == 0)
1006 /* The function moan_smtp_batch() does not return. */
1007 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1008
1009 /* Check maximum number allowed */
1010
1011 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1012 /* The function moan_smtp_batch() does not return. */
1013 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1014 recipients_max_reject? "552": "452");
1015
1016 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1017 recipient address */
1018
1019 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1020 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
1021 global_rewrite_rules) : smtp_cmd_argument;
1022
1023 /* rfc821_domains = TRUE; << no longer needed */
1024 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1025 &recipient_domain, FALSE);
1026 /* rfc821_domains = FALSE; << no longer needed */
1027
1028 if (recipient == NULL)
1029 /* The function moan_smtp_batch() does not return. */
1030 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1031
1032 /* If the recipient address is unqualified, qualify it if permitted. Then
1033 add it to the list of recipients. */
1034
1035 if (recipient_domain == 0)
1036 {
1037 if (allow_unqualified_recipient)
1038 {
1039 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1040 recipient);
1041 recipient = rewrite_address_qualify(recipient, TRUE);
1042 }
1043 /* The function moan_smtp_batch() does not return. */
1044 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1045 "a domain");
1046 }
1047 receive_add_recipient(recipient, -1);
1048 break;
1049
1050
1051 /* The DATA command is legal only if it follows successful MAIL FROM
1052 and RCPT TO commands. This function is complete when a valid DATA
1053 command is encountered. */
1054
1055 case DATA_CMD:
1056 if (sender_address == NULL || recipients_count <= 0)
1057 {
1058 /* The function moan_smtp_batch() does not return. */
1059 if (sender_address == NULL)
1060 moan_smtp_batch(smtp_cmd_buffer,
1061 "503 MAIL FROM:<sender> command must precede DATA");
1062 else
1063 moan_smtp_batch(smtp_cmd_buffer,
1064 "503 RCPT TO:<recipient> must precede DATA");
1065 }
1066 else
1067 {
1068 done = 3; /* DATA successfully achieved */
1069 message_ended = END_NOTENDED; /* Indicate in middle of message */
1070 }
1071 break;
1072
1073
1074 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1075
1076 case VRFY_CMD:
1077 case EXPN_CMD:
1078 case HELP_CMD:
1079 case NOOP_CMD:
1080 case ETRN_CMD:
1081 bsmtp_transaction_linecount = receive_linecount;
1082 break;
1083
1084
1085 case EOF_CMD:
1086 case QUIT_CMD:
1087 done = 2;
1088 break;
1089
1090
1091 case BADARG_CMD:
1092 /* The function moan_smtp_batch() does not return. */
1093 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1094 break;
1095
1096
1097 case BADCHAR_CMD:
1098 /* The function moan_smtp_batch() does not return. */
1099 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1100 break;
1101
1102
1103 default:
1104 /* The function moan_smtp_batch() does not return. */
1105 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1106 break;
1107 }
1108 }
1109
1110 return done - 2; /* Convert yield values */
1111 }
1112
1113
1114
1115
1116 /*************************************************
1117 * Start an SMTP session *
1118 *************************************************/
1119
1120 /* This function is called at the start of an SMTP session. Thereafter,
1121 smtp_setup_msg() is called to initiate each separate message. This
1122 function does host-specific testing, and outputs the banner line.
1123
1124 Arguments: none
1125 Returns: FALSE if the session can not continue; something has
1126 gone wrong, or the connection to the host is blocked
1127 */
1128
1129 BOOL
1130 smtp_start_session(void)
1131 {
1132 int size = 256;
1133 int i, ptr;
1134 uschar *p, *s, *ss;
1135
1136 /* Default values for certain variables */
1137
1138 helo_seen = esmtp = helo_accept_junk = FALSE;
1139 count_nonmail = TRUE_UNSET;
1140 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1141 smtp_delay_mail = smtp_rlm_base;
1142 auth_advertised = FALSE;
1143 pipelining_advertised = FALSE;
1144 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1145
1146 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1147
1148 sender_host_authenticated = NULL;
1149 authenticated_by = NULL;
1150
1151 #ifdef SUPPORT_TLS
1152 tls_cipher = tls_peerdn = NULL;
1153 tls_advertised = FALSE;
1154 #endif
1155
1156 /* Reset ACL connection variables */
1157
1158 for (i = 0; i < ACL_CVARS; i++) acl_var[i] = NULL;
1159
1160 /* Allow for trailing 0 in the command buffer. */
1161
1162 smtp_cmd_buffer = (uschar *)malloc(smtp_cmd_buffer_size + 1);
1163 if (smtp_cmd_buffer == NULL)
1164 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1165 "malloc() failed for SMTP command buffer");
1166
1167 /* For batched input, the protocol setting can be overridden from the
1168 command line by a trusted caller. */
1169
1170 if (smtp_batched_input)
1171 {
1172 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1173 }
1174
1175 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1176 reset later if any of EHLO/AUTH/STARTTLS are received. */
1177
1178 else
1179 received_protocol =
1180 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1181
1182 /* Set up the buffer for inputting using direct read() calls, and arrange to
1183 call the local functions instead of the standard C ones. */
1184
1185 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1186 if (smtp_inbuffer == NULL)
1187 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1188 receive_getc = smtp_getc;
1189 receive_ungetc = smtp_ungetc;
1190 receive_feof = smtp_feof;
1191 receive_ferror = smtp_ferror;
1192 smtp_inptr = smtp_inend = smtp_inbuffer;
1193 smtp_had_eof = smtp_had_error = 0;
1194
1195 /* Set up the message size limit; this may be host-specific */
1196
1197 thismessage_size_limit = expand_string_integer(message_size_limit);
1198 if (thismessage_size_limit < 0)
1199 {
1200 if (thismessage_size_limit == -1)
1201 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1202 "%s", expand_string_message);
1203 else
1204 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1205 "%s", expand_string_message);
1206 smtp_closedown(US"Temporary local problem - please try later");
1207 return FALSE;
1208 }
1209
1210 /* When a message is input locally via the -bs or -bS options, sender_host_
1211 unknown is set unless -oMa was used to force an IP address, in which case it
1212 is checked like a real remote connection. When -bs is used from inetd, this
1213 flag is not set, causing the sending host to be checked. The code that deals
1214 with IP source routing (if configured) is never required for -bs or -bS and
1215 the flag sender_host_notsocket is used to suppress it.
1216
1217 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1218 reserve for certain hosts and/or networks. */
1219
1220 if (!sender_host_unknown)
1221 {
1222 int rc;
1223 BOOL reserved_host = FALSE;
1224
1225 /* Look up IP options (source routing info) on the socket if this is not an
1226 -oMa "host", and if any are found, log them and drop the connection.
1227
1228 Linux (and others now, see below) is different to everyone else, so there
1229 has to be some conditional compilation here. Versions of Linux before 2.1.15
1230 used a structure whose name was "options". Somebody finally realized that
1231 this name was silly, and it got changed to "ip_options". I use the
1232 newer name here, but there is a fudge in the script that sets up os.h
1233 to define a macro in older Linux systems.
1234
1235 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1236 glibc 2, which has chosen ip_opts for the structure name. This is now
1237 really a glibc thing rather than a Linux thing, so the condition name
1238 has been changed to reflect this. It is relevant also to GNU/Hurd.
1239
1240 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1241 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1242 a special macro defined in the os.h file.
1243
1244 Some DGUX versions on older hardware appear not to support IP options at
1245 all, so there is now a general macro which can be set to cut out this
1246 support altogether.
1247
1248 How to do this properly in IPv6 is not yet known. */
1249
1250 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1251
1252 #ifdef GLIBC_IP_OPTIONS
1253 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1254 #define OPTSTYLE 1
1255 #else
1256 #define OPTSTYLE 2
1257 #endif
1258 #elif defined DARWIN_IP_OPTIONS
1259 #define OPTSTYLE 2
1260 #else
1261 #define OPTSTYLE 3
1262 #endif
1263
1264 if (!host_checking && !sender_host_notsocket)
1265 {
1266 #if OPTSTYLE == 1
1267 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1268 struct ip_options *ipopt = store_get(optlen);
1269 #elif OPTSTYLE == 2
1270 struct ip_opts ipoptblock;
1271 struct ip_opts *ipopt = &ipoptblock;
1272 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1273 #else
1274 struct ipoption ipoptblock;
1275 struct ipoption *ipopt = &ipoptblock;
1276 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1277 #endif
1278
1279 /* Occasional genuine failures of getsockopt() have been seen - for
1280 example, "reset by peer". Therefore, just log and give up on this
1281 call, unless the error is ENOPROTOOPT. This error is given by systems
1282 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1283 of writing. So for that error, carry on - we just can't do an IP options
1284 check. */
1285
1286 DEBUG(D_receive) debug_printf("checking for IP options\n");
1287
1288 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1289 &optlen) < 0)
1290 {
1291 if (errno != ENOPROTOOPT)
1292 {
1293 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1294 host_and_ident(FALSE), strerror(errno));
1295 smtp_printf("451 SMTP service not available\r\n");
1296 return FALSE;
1297 }
1298 }
1299
1300 /* Deal with any IP options that are set. On the systems I have looked at,
1301 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1302 more logging data than will fit in big_buffer. Nevertheless, after somebody
1303 questioned this code, I've added in some paranoid checking. */
1304
1305 else if (optlen > 0)
1306 {
1307 uschar *p = big_buffer;
1308 uschar *pend = big_buffer + big_buffer_size;
1309 uschar *opt, *adptr;
1310 int optcount;
1311 struct in_addr addr;
1312
1313 #if OPTSTYLE == 1
1314 uschar *optstart = (uschar *)(ipopt->__data);
1315 #elif OPTSTYLE == 2
1316 uschar *optstart = (uschar *)(ipopt->ip_opts);
1317 #else
1318 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1319 #endif
1320
1321 DEBUG(D_receive) debug_printf("IP options exist\n");
1322
1323 Ustrcpy(p, "IP options on incoming call:");
1324 p += Ustrlen(p);
1325
1326 for (opt = optstart; opt != NULL &&
1327 opt < (uschar *)(ipopt) + optlen;)
1328 {
1329 switch (*opt)
1330 {
1331 case IPOPT_EOL:
1332 opt = NULL;
1333 break;
1334
1335 case IPOPT_NOP:
1336 opt++;
1337 break;
1338
1339 case IPOPT_SSRR:
1340 case IPOPT_LSRR:
1341 if (!string_format(p, pend-p, " %s [@%s",
1342 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1343 #if OPTSTYLE == 1
1344 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1345 #elif OPTSTYLE == 2
1346 inet_ntoa(ipopt->ip_dst)))
1347 #else
1348 inet_ntoa(ipopt->ipopt_dst)))
1349 #endif
1350 {
1351 opt = NULL;
1352 break;
1353 }
1354
1355 p += Ustrlen(p);
1356 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1357 adptr = opt + 3;
1358 while (optcount-- > 0)
1359 {
1360 memcpy(&addr, adptr, sizeof(addr));
1361 if (!string_format(p, pend - p - 1, "%s%s",
1362 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1363 {
1364 opt = NULL;
1365 break;
1366 }
1367 p += Ustrlen(p);
1368 adptr += sizeof(struct in_addr);
1369 }
1370 *p++ = ']';
1371 opt += opt[1];
1372 break;
1373
1374 default:
1375 {
1376 int i;
1377 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1378 Ustrcat(p, "[ ");
1379 p += 2;
1380 for (i = 0; i < opt[1]; i++)
1381 {
1382 sprintf(CS p, "%2.2x ", opt[i]);
1383 p += 3;
1384 }
1385 *p++ = ']';
1386 }
1387 opt += opt[1];
1388 break;
1389 }
1390 }
1391
1392 *p = 0;
1393 log_write(0, LOG_MAIN, "%s", big_buffer);
1394
1395 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1396
1397 log_write(0, LOG_MAIN|LOG_REJECT,
1398 "connection from %s refused (IP options)", host_and_ident(FALSE));
1399
1400 smtp_printf("554 SMTP service not available\r\n");
1401 return FALSE;
1402 }
1403
1404 /* Length of options = 0 => there are no options */
1405
1406 else DEBUG(D_receive) debug_printf("no IP options found\n");
1407 }
1408 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1409
1410 /* Set keep-alive in socket options. The option is on by default. This
1411 setting is an attempt to get rid of some hanging connections that stick in
1412 read() when the remote end (usually a dialup) goes away. */
1413
1414 if (smtp_accept_keepalive && !sender_host_notsocket)
1415 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1416
1417 /* If the current host matches host_lookup, set the name by doing a
1418 reverse lookup. On failure, sender_host_name will be NULL and
1419 host_lookup_failed will be TRUE. This may or may not be serious - optional
1420 checks later. */
1421
1422 if (verify_check_host(&host_lookup) == OK)
1423 {
1424 (void)host_name_lookup();
1425 host_build_sender_fullhost();
1426 }
1427
1428 /* Delay this until we have the full name, if it is looked up. */
1429
1430 set_process_info("handling incoming connection from %s",
1431 host_and_ident(FALSE));
1432
1433 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1434 smtps port for use with older style SSL MTAs. */
1435
1436 #ifdef SUPPORT_TLS
1437 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1438 return FALSE;
1439 #endif
1440
1441 /* Test for explicit connection rejection */
1442
1443 if (verify_check_host(&host_reject_connection) == OK)
1444 {
1445 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1446 "from %s (host_reject_connection)", host_and_ident(FALSE));
1447 smtp_printf("554 SMTP service not available\r\n");
1448 return FALSE;
1449 }
1450
1451 /* Test with TCP Wrappers if so configured */
1452
1453 #ifdef USE_TCP_WRAPPERS
1454 if (!hosts_ctl("exim",
1455 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1456 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1457 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1458 {
1459 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1460 log_write(L_connection_reject,
1461 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1462 "(tcp wrappers)", host_and_ident(FALSE));
1463 smtp_printf("554 SMTP service not available\r\n");
1464 return FALSE;
1465 }
1466 #endif
1467
1468 /* Check for reserved slots. Note that the count value doesn't include
1469 this process, as it gets upped in the parent process. */
1470
1471 if (smtp_accept_max > 0 &&
1472 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1473 {
1474 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1475 {
1476 log_write(L_connection_reject,
1477 LOG_MAIN, "temporarily refused connection from %s: not in "
1478 "reserve list: connected=%d max=%d reserve=%d%s",
1479 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1480 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1481 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1482 "please try again later\r\n", smtp_active_hostname);
1483 return FALSE;
1484 }
1485 reserved_host = TRUE;
1486 }
1487
1488 /* If a load level above which only messages from reserved hosts are
1489 accepted is set, check the load. For incoming calls via the daemon, the
1490 check is done in the superior process if there are no reserved hosts, to
1491 save a fork. In all cases, the load average will already be available
1492 in a global variable at this point. */
1493
1494 if (smtp_load_reserve >= 0 &&
1495 load_average > smtp_load_reserve &&
1496 !reserved_host &&
1497 verify_check_host(&smtp_reserve_hosts) != OK)
1498 {
1499 log_write(L_connection_reject,
1500 LOG_MAIN, "temporarily refused connection from %s: not in "
1501 "reserve list and load average = %.2f", host_and_ident(FALSE),
1502 (double)load_average/1000.0);
1503 smtp_printf("421 %s: Too much load; please try again later\r\n",
1504 smtp_active_hostname);
1505 return FALSE;
1506 }
1507
1508 /* Determine whether unqualified senders or recipients are permitted
1509 for this host. Unfortunately, we have to do this every time, in order to
1510 set the flags so that they can be inspected when considering qualifying
1511 addresses in the headers. For a site that permits no qualification, this
1512 won't take long, however. */
1513
1514 allow_unqualified_sender =
1515 verify_check_host(&sender_unqualified_hosts) == OK;
1516
1517 allow_unqualified_recipient =
1518 verify_check_host(&recipient_unqualified_hosts) == OK;
1519
1520 /* Determine whether HELO/EHLO is required for this host. The requirement
1521 can be hard or soft. */
1522
1523 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1524 if (!helo_required)
1525 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1526
1527 /* Determine whether this hosts is permitted to send syntactic junk
1528 after a HELO or EHLO command. */
1529
1530 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1531 }
1532
1533 /* For batch SMTP input we are now done. */
1534
1535 if (smtp_batched_input) return TRUE;
1536
1537 /* Run the ACL if it exists */
1538
1539 if (acl_smtp_connect != NULL)
1540 {
1541 int rc;
1542 uschar *user_msg, *log_msg;
1543 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1544 &log_msg);
1545 if (rc != OK)
1546 {
1547 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1548 return FALSE;
1549 }
1550 }
1551
1552 /* Output the initial message for a two-way SMTP connection. It may contain
1553 newlines, which then cause a multi-line response to be given. */
1554
1555 s = expand_string(smtp_banner);
1556 if (s == NULL)
1557 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1558 "failed: %s", smtp_banner, expand_string_message);
1559
1560 /* Remove any terminating newlines; might as well remove trailing space too */
1561
1562 p = s + Ustrlen(s);
1563 while (p > s && isspace(p[-1])) p--;
1564 *p = 0;
1565
1566 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1567 is all contained in a single IP packet. The original code wrote out the
1568 greeting using several calls to fprint/fputc, and on busy servers this could
1569 cause it to be split over more than one packet - which caused CC:Mail to fall
1570 over when it got the second part of the greeting after sending its first
1571 command. Sigh. To try to avoid this, build the complete greeting message
1572 first, and output it in one fell swoop. This gives a better chance of it
1573 ending up as a single packet. */
1574
1575 ss = store_get(size);
1576 ptr = 0;
1577
1578 p = s;
1579 do /* At least once, in case we have an empty string */
1580 {
1581 int len;
1582 uschar *linebreak = Ustrchr(p, '\n');
1583 if (linebreak == NULL)
1584 {
1585 len = Ustrlen(p);
1586 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1587 }
1588 else
1589 {
1590 len = linebreak - p;
1591 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1592 }
1593 ss = string_cat(ss, &size, &ptr, p, len);
1594 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1595 p += len;
1596 if (linebreak != NULL) p++;
1597 }
1598 while (*p != 0);
1599
1600 ss[ptr] = 0; /* string_cat leaves room for this */
1601
1602 /* Before we write the banner, check that there is no input pending, unless
1603 this synchronisation check is disabled. */
1604
1605 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1606 {
1607 fd_set fds;
1608 struct timeval tzero;
1609 tzero.tv_sec = 0;
1610 tzero.tv_usec = 0;
1611 FD_ZERO(&fds);
1612 FD_SET(fileno(smtp_in), &fds);
1613 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1614 &tzero) > 0)
1615 {
1616 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1617 if (rc > 0)
1618 {
1619 if (rc > 150) rc = 150;
1620 smtp_inbuffer[rc] = 0;
1621 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1622 "synchronization error (input sent without waiting for greeting): "
1623 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1624 string_printing(smtp_inbuffer));
1625 smtp_printf("554 SMTP synchronization error\r\n");
1626 return FALSE;
1627 }
1628 }
1629 }
1630
1631 /* Now output the banner */
1632
1633 smtp_printf("%s", ss);
1634 return TRUE;
1635 }
1636
1637
1638
1639
1640
1641 /*************************************************
1642 * Handle SMTP syntax and protocol errors *
1643 *************************************************/
1644
1645 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1646 to do so. Then transmit the error response. The return value depends on the
1647 number of syntax and protocol errors in this SMTP session.
1648
1649 Arguments:
1650 type error type, given as a log flag bit
1651 code response code; <= 0 means don't send a response
1652 data data to reflect in the response (can be NULL)
1653 errmess the error message
1654
1655 Returns: -1 limit of syntax/protocol errors NOT exceeded
1656 +1 limit of syntax/protocol errors IS exceeded
1657
1658 These values fit in with the values of the "done" variable in the main
1659 processing loop in smtp_setup_msg(). */
1660
1661 static int
1662 synprot_error(int type, int code, uschar *data, uschar *errmess)
1663 {
1664 int yield = -1;
1665
1666 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1667 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1668 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1669
1670 if (++synprot_error_count > smtp_max_synprot_errors)
1671 {
1672 yield = 1;
1673 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1674 "syntax or protocol errors (last command was \"%s\")",
1675 host_and_ident(FALSE), smtp_cmd_buffer);
1676 }
1677
1678 if (code > 0)
1679 {
1680 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1681 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1682 if (yield == 1)
1683 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1684 }
1685
1686 return yield;
1687 }
1688
1689
1690
1691
1692 /*************************************************
1693 * Log incomplete transactions *
1694 *************************************************/
1695
1696 /* This function is called after a transaction has been aborted by RSET, QUIT,
1697 connection drops or other errors. It logs the envelope information received
1698 so far in order to preserve address verification attempts.
1699
1700 Argument: string to indicate what aborted the transaction
1701 Returns: nothing
1702 */
1703
1704 static void
1705 incomplete_transaction_log(uschar *what)
1706 {
1707 if (sender_address == NULL || /* No transaction in progress */
1708 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1709 ) return;
1710
1711 /* Build list of recipients for logging */
1712
1713 if (recipients_count > 0)
1714 {
1715 int i;
1716 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1717 for (i = 0; i < recipients_count; i++)
1718 raw_recipients[i] = recipients_list[i].address;
1719 raw_recipients_count = recipients_count;
1720 }
1721
1722 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1723 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1724 }
1725
1726
1727
1728
1729 /*************************************************
1730 * Send SMTP response, possibly multiline *
1731 *************************************************/
1732
1733 /* There are, it seems, broken clients out there that cannot handle multiline
1734 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1735 output nothing for non-final calls, and only the first line for anything else.
1736
1737 Arguments:
1738 code SMTP code
1739 final FALSE if the last line isn't the final line
1740 msg message text, possibly containing newlines
1741
1742 Returns: nothing
1743 */
1744
1745 void
1746 smtp_respond(int code, BOOL final, uschar *msg)
1747 {
1748 if (!final && no_multiline_responses) return;
1749
1750 for (;;)
1751 {
1752 uschar *nl = Ustrchr(msg, '\n');
1753 if (nl == NULL)
1754 {
1755 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1756 return;
1757 }
1758 else if (nl[1] == 0 || no_multiline_responses)
1759 {
1760 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1761 return;
1762 }
1763 else
1764 {
1765 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1766 msg = nl + 1;
1767 while (isspace(*msg)) msg++;
1768 }
1769 }
1770 }
1771
1772
1773
1774
1775 /*************************************************
1776 * Handle an ACL failure *
1777 *************************************************/
1778
1779 /* This function is called when acl_check() fails. As well as calls from within
1780 this module, it is called from receive.c for an ACL after DATA. It sorts out
1781 logging the incident, and sets up the error response. A message containing
1782 newlines is turned into a multiline SMTP response, but for logging, only the
1783 first line is used.
1784
1785 There's a table of the response codes to use in globals.c, along with the table
1786 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1787 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1788 that the response should be 252 in the disabled state, because there are broken
1789 clients that try VRFY before RCPT. A 5xx response should be given only when the
1790 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1791 given on refusal, and for AUTH, 503.
1792
1793 Arguments:
1794 where where the ACL was called from
1795 rc the failure code
1796 user_msg a message that can be included in an SMTP response
1797 log_msg a message for logging
1798
1799 Returns: 0 in most cases
1800 2 if the failure code was FAIL_DROP, in which case the
1801 SMTP connection should be dropped (this value fits with the
1802 "done" variable in smtp_setup_msg() below)
1803 */
1804
1805 int
1806 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1807 {
1808 int code = acl_wherecodes[where];
1809 BOOL drop = rc == FAIL_DROP;
1810 uschar *lognl;
1811 uschar *sender_info = US"";
1812 uschar *what =
1813 #ifdef WITH_CONTENT_SCAN
1814 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1815 #endif
1816 (where == ACL_WHERE_PREDATA)? US"DATA" :
1817 (where == ACL_WHERE_DATA)? US"after DATA" :
1818 (smtp_cmd_argument == NULL)?
1819 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
1820 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_argument);
1821
1822 if (drop) rc = FAIL;
1823
1824 /* We used to have sender_address here; however, there was a bug that was not
1825 updating sender_address after a rewrite during a verify. When this bug was
1826 fixed, sender_address at this point became the rewritten address. I'm not sure
1827 this is what should be logged, so I've changed to logging the unrewritten
1828 address to retain backward compatibility. */
1829
1830 #ifndef WITH_CONTENT_SCAN
1831 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1832 #else
1833 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1834 #endif
1835 {
1836 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1837 sender_address_unrewritten : sender_address);
1838 }
1839
1840 /* If there's been a sender verification failure with a specific message, and
1841 we have not sent a response about it yet, do so now, as a preliminary line for
1842 failures, but not defers. However, log it in both cases. */
1843
1844 if (sender_verified_failed != NULL &&
1845 !testflag(sender_verified_failed, af_sverify_told))
1846 {
1847 setflag(sender_verified_failed, af_sverify_told);
1848
1849 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1850 host_and_ident(TRUE),
1851 ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail",
1852 sender_verified_failed->address,
1853 (sender_verified_failed->message == NULL)? US"" :
1854 string_sprintf(": %s", sender_verified_failed->message));
1855
1856 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1857 smtp_respond(code, FALSE, string_sprintf(
1858 testflag(sender_verified_failed, af_verify_pmfail)?
1859 "Postmaster verification failed while checking <%s>\n%s\n"
1860 "Several RFCs state that you are required to have a postmaster\n"
1861 "mailbox for each mail domain. This host does not accept mail\n"
1862 "from domains whose servers reject the postmaster address."
1863 :
1864 testflag(sender_verified_failed, af_verify_nsfail)?
1865 "Callback setup failed while verifying <%s>\n%s\n"
1866 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1867 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1868 "RFC requirements, and stops you from receiving standard bounce\n"
1869 "messages. This host does not accept mail from domains whose servers\n"
1870 "refuse bounces."
1871 :
1872 "Verification failed for <%s>\n%s",
1873 sender_verified_failed->address,
1874 sender_verified_failed->user_message));
1875 }
1876
1877 /* Sort out text for logging */
1878
1879 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1880 lognl = Ustrchr(log_msg, '\n');
1881 if (lognl != NULL) *lognl = 0;
1882
1883 /* Send permanent failure response to the command, but the code used isn't
1884 always a 5xx one - see comments at the start of this function. If the original
1885 rc was FAIL_DROP we drop the connection and yield 2. */
1886
1887 if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1888 US"Administrative prohibition" : user_msg);
1889
1890 /* Send temporary failure response to the command. Don't give any details,
1891 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1892 verb, and for a header verify when smtp_return_error_details is set.
1893
1894 This conditional logic is all somewhat of a mess because of the odd
1895 interactions between temp_details and return_error_details. One day it should
1896 be re-implemented in a tidier fashion. */
1897
1898 else
1899 {
1900 if (acl_temp_details && user_msg != NULL)
1901 {
1902 if (smtp_return_error_details &&
1903 sender_verified_failed != NULL &&
1904 sender_verified_failed->message != NULL)
1905 {
1906 smtp_respond(451, FALSE, sender_verified_failed->message);
1907 }
1908 smtp_respond(451, TRUE, user_msg);
1909 }
1910 else
1911 smtp_printf("451 Temporary local problem - please try later\r\n");
1912 }
1913
1914 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
1915 Otherwise, log why it is closing if required and return 2. */
1916
1917 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1918 host_and_ident(TRUE),
1919 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1920
1921 if (!drop) return 0;
1922
1923 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1924 smtp_get_connection_info());
1925 return 2;
1926 }
1927
1928
1929
1930
1931 /*************************************************
1932 * Verify HELO argument *
1933 *************************************************/
1934
1935 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
1936 matched. It is also called from ACL processing if verify = helo is used and
1937 verification was not previously tried (i.e. helo_try_verify_hosts was not
1938 matched). The result of its processing is to set helo_verified and
1939 helo_verify_failed. These variables should both be FALSE for this function to
1940 be called.
1941
1942 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
1943 for IPv6 ::ffff: literals.
1944
1945 Argument: none
1946 Returns: TRUE if testing was completed;
1947 FALSE on a temporary failure
1948 */
1949
1950 BOOL
1951 smtp_verify_helo(void)
1952 {
1953 BOOL yield = TRUE;
1954
1955 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
1956 sender_helo_name);
1957
1958 if (sender_helo_name == NULL)
1959 {
1960 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
1961 }
1962
1963 else if (sender_helo_name[0] == '[')
1964 {
1965 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
1966 Ustrlen(sender_host_address)) == 0;
1967
1968 #if HAVE_IPV6
1969 if (!helo_verified)
1970 {
1971 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
1972 helo_verified = Ustrncmp(sender_helo_name + 1,
1973 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
1974 }
1975 #endif
1976
1977 HDEBUG(D_receive)
1978 { if (helo_verified) debug_printf("matched host address\n"); }
1979 }
1980
1981 /* Do a reverse lookup if one hasn't already given a positive or negative
1982 response. If that fails, or the name doesn't match, try checking with a forward
1983 lookup. */
1984
1985 else
1986 {
1987 if (sender_host_name == NULL && !host_lookup_failed)
1988 yield = host_name_lookup() != DEFER;
1989
1990 /* If a host name is known, check it and all its aliases. */
1991
1992 if (sender_host_name != NULL)
1993 {
1994 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
1995
1996 if (helo_verified)
1997 {
1998 HDEBUG(D_receive) debug_printf("matched host name\n");
1999 }
2000 else
2001 {
2002 uschar **aliases = sender_host_aliases;
2003 while (*aliases != NULL)
2004 {
2005 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2006 if (helo_verified) break;
2007 }
2008 HDEBUG(D_receive)
2009 {
2010 if (helo_verified)
2011 debug_printf("matched alias %s\n", *(--aliases));
2012 }
2013 }
2014 }
2015
2016 /* Final attempt: try a forward lookup of the helo name */
2017
2018 if (!helo_verified)
2019 {
2020 int rc;
2021 host_item h;
2022 h.name = sender_helo_name;
2023 h.address = NULL;
2024 h.mx = MX_NONE;
2025 h.next = NULL;
2026 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2027 sender_helo_name);
2028 rc = host_find_byname(&h, NULL, NULL, TRUE);
2029 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2030 {
2031 host_item *hh = &h;
2032 while (hh != NULL)
2033 {
2034 if (Ustrcmp(hh->address, sender_host_address) == 0)
2035 {
2036 helo_verified = TRUE;
2037 HDEBUG(D_receive)
2038 debug_printf("IP address for %s matches calling address\n",
2039 sender_helo_name);
2040 break;
2041 }
2042 hh = hh->next;
2043 }
2044 }
2045 }
2046 }
2047
2048 if (!helo_verified) helo_verify_failed = FALSE; /* We've tried ... */
2049 return yield;
2050 }
2051
2052
2053
2054
2055 /*************************************************
2056 * Initialize for SMTP incoming message *
2057 *************************************************/
2058
2059 /* This function conducts the initial dialogue at the start of an incoming SMTP
2060 message, and builds a list of recipients. However, if the incoming message
2061 is part of a batch (-bS option) a separate function is called since it would
2062 be messy having tests splattered about all over this function. This function
2063 therefore handles the case where interaction is occurring. The input and output
2064 files are set up in smtp_in and smtp_out.
2065
2066 The global recipients_list is set to point to a vector of recipient_item
2067 blocks, whose number is given by recipients_count. This is extended by the
2068 receive_add_recipient() function. The global variable sender_address is set to
2069 the sender's address. The yield is +1 if a message has been successfully
2070 started, 0 if a QUIT command was encountered or the connection was refused from
2071 the particular host, or -1 if the connection was lost.
2072
2073 Argument: none
2074
2075 Returns: > 0 message successfully started (reached DATA)
2076 = 0 QUIT read or end of file reached or call refused
2077 < 0 lost connection
2078 */
2079
2080 int
2081 smtp_setup_msg(void)
2082 {
2083 int done = 0;
2084 BOOL toomany = FALSE;
2085 BOOL discarded = FALSE;
2086 BOOL last_was_rej_mail = FALSE;
2087 BOOL last_was_rcpt = FALSE;
2088 void *reset_point = store_get(0);
2089
2090 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2091
2092 /* Reset for start of new message. We allow one RSET not to be counted as a
2093 nonmail command, for those MTAs that insist on sending it between every
2094 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2095 TLS between messages (an Exim client may do this if it has messages queued up
2096 for the host). Note: we do NOT reset AUTH at this point. */
2097
2098 smtp_reset(reset_point);
2099 message_ended = END_NOTSTARTED;
2100
2101 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2102 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2103 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2104 #ifdef SUPPORT_TLS
2105 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2106 #endif
2107
2108 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2109
2110 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2111
2112 /* Batched SMTP is handled in a different function. */
2113
2114 if (smtp_batched_input) return smtp_setup_batch_msg();
2115
2116 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2117 value. The values are 2 larger than the required yield of the function. */
2118
2119 while (done <= 0)
2120 {
2121 uschar **argv;
2122 uschar *etrn_command;
2123 uschar *etrn_serialize_key;
2124 uschar *errmess;
2125 uschar *user_msg, *log_msg;
2126 uschar *recipient = NULL;
2127 uschar *hello = NULL;
2128 uschar *set_id = NULL;
2129 uschar *s, *ss;
2130 BOOL was_rej_mail = FALSE;
2131 BOOL was_rcpt = FALSE;
2132 void (*oldsignal)(int);
2133 pid_t pid;
2134 int start, end, sender_domain, recipient_domain;
2135 int ptr, size, rc;
2136 int c;
2137 auth_instance *au;
2138
2139 switch(smtp_read_command(TRUE))
2140 {
2141 /* The AUTH command is not permitted to occur inside a transaction, and may
2142 occur successfully only once per connection, and then only when we've
2143 advertised it. Actually, that isn't quite true. When TLS is started, all
2144 previous information about a connection must be discarded, so a new AUTH is
2145 permitted at that time.
2146
2147 AUTH is initially labelled as a "nonmail command" so that one occurrence
2148 doesn't get counted. We change the label here so that multiple failing
2149 AUTHS will eventually hit the nonmail threshold. */
2150
2151 case AUTH_CMD:
2152 authentication_failed = TRUE;
2153 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2154
2155 if (!auth_advertised)
2156 {
2157 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2158 US"AUTH command used when not advertised");
2159 break;
2160 }
2161 if (sender_host_authenticated != NULL)
2162 {
2163 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2164 US"already authenticated");
2165 break;
2166 }
2167 if (sender_address != NULL)
2168 {
2169 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2170 US"not permitted in mail transaction");
2171 break;
2172 }
2173
2174 /* Check the ACL */
2175
2176 if (acl_smtp_auth != NULL)
2177 {
2178 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2179 if (rc != OK)
2180 {
2181 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2182 break;
2183 }
2184 }
2185
2186 /* Find the name of the requested authentication mechanism. */
2187
2188 s = smtp_cmd_argument;
2189 while ((c = *smtp_cmd_argument) != 0 && !isspace(c))
2190 {
2191 if (!isalnum(c) && c != '-' && c != '_')
2192 {
2193 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2194 US"invalid character in authentication mechanism name");
2195 goto COMMAND_LOOP;
2196 }
2197 smtp_cmd_argument++;
2198 }
2199
2200 /* If not at the end of the line, we must be at white space. Terminate the
2201 name and move the pointer on to any data that may be present. */
2202
2203 if (*smtp_cmd_argument != 0)
2204 {
2205 *smtp_cmd_argument++ = 0;
2206 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
2207 }
2208
2209 /* Search for an authentication mechanism which is configured for use
2210 as a server and which has been advertised. */
2211
2212 for (au = auths; au != NULL; au = au->next)
2213 {
2214 if (strcmpic(s, au->public_name) == 0 && au->server &&
2215 au->advertised) break;
2216 }
2217
2218 if (au == NULL)
2219 {
2220 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2221 string_sprintf("%s authentication mechanism not supported", s));
2222 break;
2223 }
2224
2225 /* Run the checking code, passing the remainder of the command
2226 line as data. Initialize $0 empty. The authenticator may set up
2227 other numeric variables. Afterwards, have a go at expanding the set_id
2228 string, even if authentication failed - for bad passwords it can be useful
2229 to log the userid. On success, require set_id to expand and exist, and
2230 put it in authenticated_id. Save this in permanent store, as the working
2231 store gets reset at HELO, RSET, etc. */
2232
2233 expand_nmax = 0;
2234 expand_nlength[0] = 0; /* $0 contains nothing */
2235
2236 c = (au->info->servercode)(au, smtp_cmd_argument);
2237 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2238 expand_nmax = -1; /* Reset numeric variables */
2239
2240 /* The value of authenticated_id is stored in the spool file and printed in
2241 log lines. It must not contain binary zeros or newline characters. In
2242 normal use, it never will, but when playing around or testing, this error
2243 can (did) happen. To guard against this, ensure that the id contains only
2244 printing characters. */
2245
2246 if (set_id != NULL) set_id = string_printing(set_id);
2247
2248 /* For the non-OK cases, set up additional logging data if set_id
2249 is not empty. */
2250
2251 if (c != OK)
2252 {
2253 if (set_id != NULL && *set_id != 0)
2254 set_id = string_sprintf(" (set_id=%s)", set_id);
2255 else set_id = US"";
2256 }
2257
2258 /* Switch on the result */
2259
2260 switch(c)
2261 {
2262 case OK:
2263 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2264 {
2265 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2266 sender_host_authenticated = au->name;
2267 authentication_failed = FALSE;
2268 received_protocol =
2269 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2270 ((sender_host_address != NULL)? pnlocal : 0);
2271 s = ss = US"235 Authentication succeeded";
2272 authenticated_by = au;
2273 break;
2274 }
2275
2276 /* Authentication succeeded, but we failed to expand the set_id string.
2277 Treat this as a temporary error. */
2278
2279 auth_defer_msg = expand_string_message;
2280 /* Fall through */
2281
2282 case DEFER:
2283 s = string_sprintf("435 Unable to authenticate at present%s",
2284 auth_defer_user_msg);
2285 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2286 set_id, auth_defer_msg);
2287 break;
2288
2289 case BAD64:
2290 s = ss = US"501 Invalid base64 data";
2291 break;
2292
2293 case CANCELLED:
2294 s = ss = US"501 Authentication cancelled";
2295 break;
2296
2297 case UNEXPECTED:
2298 s = ss = US"553 Initial data not expected";
2299 break;
2300
2301 case FAIL:
2302 s = US"535 Incorrect authentication data";
2303 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2304 break;
2305
2306 default:
2307 s = US"435 Internal error";
2308 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2309 "check", set_id, c);
2310 break;
2311 }
2312
2313 smtp_printf("%s\r\n", s);
2314 if (c != OK)
2315 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2316 au->name, host_and_ident(FALSE), ss);
2317
2318 break; /* AUTH_CMD */
2319
2320 /* The HELO/EHLO commands are permitted to appear in the middle of a
2321 session as well as at the beginning. They have the effect of a reset in
2322 addition to their other functions. Their absence at the start cannot be
2323 taken to be an error.
2324
2325 RFC 2821 says:
2326
2327 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2328 or 502 failure replies MUST be returned as appropriate. The SMTP
2329 server MUST stay in the same state after transmitting these replies
2330 that it was in before the EHLO was received.
2331
2332 Therefore, we do not do the reset until after checking the command for
2333 acceptability. This change was made for Exim release 4.11. Previously
2334 it did the reset first. */
2335
2336 case HELO_CMD:
2337 hello = US"HELO";
2338 esmtp = FALSE;
2339 goto HELO_EHLO;
2340
2341 case EHLO_CMD:
2342 hello = US"EHLO";
2343 esmtp = TRUE;
2344
2345 HELO_EHLO: /* Common code for HELO and EHLO */
2346 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2347 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2348
2349 /* Reject the HELO if its argument was invalid or non-existent. A
2350 successful check causes the argument to be saved in malloc store. */
2351
2352 if (!check_helo(smtp_cmd_argument))
2353 {
2354 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2355
2356 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2357 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2358 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2359 string_printing(smtp_cmd_argument));
2360
2361 if (++synprot_error_count > smtp_max_synprot_errors)
2362 {
2363 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2364 "syntax or protocol errors (last command was \"%s\")",
2365 host_and_ident(FALSE), smtp_cmd_buffer);
2366 done = 1;
2367 }
2368
2369 break;
2370 }
2371
2372 /* If sender_host_unknown is true, we have got here via the -bs interface,
2373 not called from inetd. Otherwise, we are running an IP connection and the
2374 host address will be set. If the helo name is the primary name of this
2375 host and we haven't done a reverse lookup, force one now. If helo_required
2376 is set, ensure that the HELO name matches the actual host. If helo_verify
2377 is set, do the same check, but softly. */
2378
2379 if (!sender_host_unknown)
2380 {
2381 BOOL old_helo_verified = helo_verified;
2382 uschar *p = smtp_cmd_argument;
2383
2384 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2385 *p = 0;
2386
2387 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2388 because otherwise the log can be confusing. */
2389
2390 if (sender_host_name == NULL &&
2391 (deliver_domain = sender_helo_name, /* set $domain */
2392 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2393 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2394 (void)host_name_lookup();
2395
2396 /* Rebuild the fullhost info to include the HELO name (and the real name
2397 if it was looked up.) */
2398
2399 host_build_sender_fullhost(); /* Rebuild */
2400 set_process_info("handling%s incoming connection from %s",
2401 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2402
2403 /* Verify if configured. This doesn't give much security, but it does
2404 make some people happy to be able to do it. If helo_required is set,
2405 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2406 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2407 now obsolescent, since the verification can now be requested selectively
2408 at ACL time. */
2409
2410 helo_verified = helo_verify_failed = FALSE;
2411 if (helo_required || helo_verify)
2412 {
2413 BOOL tempfail = !smtp_verify_helo();
2414 if (!helo_verified)
2415 {
2416 if (helo_required)
2417 {
2418 smtp_printf("%d %s argument does not match calling host\r\n",
2419 tempfail? 451 : 550, hello);
2420 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2421 tempfail? "temporarily " : "",
2422 hello, sender_helo_name, host_and_ident(FALSE));
2423 helo_verified = old_helo_verified;
2424 break; /* End of HELO/EHLO processing */
2425 }
2426 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2427 "helo_try_verify_hosts\n", hello);
2428 }
2429 }
2430 }
2431
2432 #ifdef EXPERIMENTAL_SPF
2433 /* set up SPF context */
2434 spf_init(sender_helo_name, sender_host_address);
2435 #endif
2436
2437 /* Apply an ACL check if one is defined */
2438
2439 if (acl_smtp_helo != NULL)
2440 {
2441 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2442 if (rc != OK)
2443 {
2444 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2445 sender_helo_name = NULL;
2446 host_build_sender_fullhost(); /* Rebuild */
2447 break;
2448 }
2449 }
2450
2451 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2452 abandoning any previous message. */
2453
2454 received_protocol = (esmtp?
2455 protocols[pextend +
2456 ((sender_host_authenticated != NULL)? pauthed : 0) +
2457 ((tls_active >= 0)? pcrpted : 0)]
2458 :
2459 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2460 +
2461 ((sender_host_address != NULL)? pnlocal : 0);
2462
2463 smtp_reset(reset_point);
2464 toomany = FALSE;
2465
2466 /* Generate an OK reply, including the ident if present, and also
2467 the IP address if present. Reflecting back the ident is intended
2468 as a deterrent to mail forgers. For maximum efficiency, and also
2469 because some broken systems expect each response to be in a single
2470 packet, arrange that it is sent in one write(). */
2471
2472 auth_advertised = FALSE;
2473 pipelining_advertised = FALSE;
2474 #ifdef SUPPORT_TLS
2475 tls_advertised = FALSE;
2476 #endif
2477
2478 s = string_sprintf("250 %s Hello %s%s%s",
2479 smtp_active_hostname,
2480 (sender_ident == NULL)? US"" : sender_ident,
2481 (sender_ident == NULL)? US"" : US" at ",
2482 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2483
2484 ptr = Ustrlen(s);
2485 size = ptr + 1;
2486
2487 if (sender_host_address != NULL)
2488 {
2489 s = string_cat(s, &size, &ptr, US" [", 2);
2490 s = string_cat(s, &size, &ptr, sender_host_address,
2491 Ustrlen(sender_host_address));
2492 s = string_cat(s, &size, &ptr, US"]", 1);
2493 }
2494
2495 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2496
2497 /* If we received EHLO, we must create a multiline response which includes
2498 the functions supported. */
2499
2500 if (esmtp)
2501 {
2502 s[3] = '-';
2503
2504 /* I'm not entirely happy with this, as an MTA is supposed to check
2505 that it has enough room to accept a message of maximum size before
2506 it sends this. However, there seems little point in not sending it.
2507 The actual size check happens later at MAIL FROM time. By postponing it
2508 till then, VRFY and EXPN can be used after EHLO when space is short. */
2509
2510 if (thismessage_size_limit > 0)
2511 {
2512 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2513 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2514 }
2515 else
2516 {
2517 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2518 }
2519
2520 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2521 clean; if it has an 8-bit character in its hand, it just sends it. It
2522 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2523 However, some users want this option simply in order to stop MUAs
2524 mangling messages that contain top-bit-set characters. It is therefore
2525 provided as an option. */
2526
2527 if (accept_8bitmime)
2528 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2529
2530 /* Advertise ETRN if there's an ACL checking whether a host is
2531 permitted to issue it; a check is made when any host actually tries. */
2532
2533 if (acl_smtp_etrn != NULL)
2534 {
2535 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2536 }
2537
2538 /* Advertise EXPN if there's an ACL checking whether a host is
2539 permitted to issue it; a check is made when any host actually tries. */
2540
2541 if (acl_smtp_expn != NULL)
2542 {
2543 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2544 }
2545
2546 /* Exim is quite happy with pipelining, so let the other end know that
2547 it is safe to use it, unless advertising is disabled. */
2548
2549 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2550 {
2551 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2552 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2553 pipelining_advertised = TRUE;
2554 }
2555
2556 /* If any server authentication mechanisms are configured, advertise
2557 them if the current host is in auth_advertise_hosts. The problem with
2558 advertising always is that some clients then require users to
2559 authenticate (and aren't configurable otherwise) even though it may not
2560 be necessary (e.g. if the host is in host_accept_relay).
2561
2562 RFC 2222 states that SASL mechanism names contain only upper case
2563 letters, so output the names in upper case, though we actually recognize
2564 them in either case in the AUTH command. */
2565
2566 if (auths != NULL)
2567 {
2568 if (verify_check_host(&auth_advertise_hosts) == OK)
2569 {
2570 auth_instance *au;
2571 BOOL first = TRUE;
2572 for (au = auths; au != NULL; au = au->next)
2573 {
2574 if (au->server && (au->advertise_condition == NULL ||
2575 expand_check_condition(au->advertise_condition, au->name,
2576 US"authenticator")))
2577 {
2578 int saveptr;
2579 if (first)
2580 {
2581 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2582 first = FALSE;
2583 auth_advertised = TRUE;
2584 }
2585 saveptr = ptr;
2586 s = string_cat(s, &size, &ptr, US" ", 1);
2587 s = string_cat(s, &size, &ptr, au->public_name,
2588 Ustrlen(au->public_name));
2589 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2590 au->advertised = TRUE;
2591 }
2592 else au->advertised = FALSE;
2593 }
2594 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2595 }
2596 }
2597
2598 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2599 if it has been included in the binary, and the host matches
2600 tls_advertise_hosts. We must *not* advertise if we are already in a
2601 secure connection. */
2602
2603 #ifdef SUPPORT_TLS
2604 if (tls_active < 0 &&
2605 verify_check_host(&tls_advertise_hosts) != FAIL)
2606 {
2607 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2608 tls_advertised = TRUE;
2609 }
2610 #endif
2611
2612 /* Finish off the multiline reply with one that is always available. */
2613
2614 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2615 }
2616
2617 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2618 has been seen. */
2619
2620 s[ptr] = 0;
2621
2622 #ifdef SUPPORT_TLS
2623 if (tls_active >= 0) (void)tls_write(s, ptr); else
2624 #endif
2625
2626 (void)fwrite(s, 1, ptr, smtp_out);
2627 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2628 helo_seen = TRUE;
2629 break; /* HELO/EHLO */
2630
2631
2632 /* The MAIL command requires an address as an operand. All we do
2633 here is to parse it for syntactic correctness. The form "<>" is
2634 a special case which converts into an empty string. The start/end
2635 pointers in the original are not used further for this address, as
2636 it is the canonical extracted address which is all that is kept. */
2637
2638 case MAIL_CMD:
2639 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2640 was_rej_mail = TRUE; /* Reset if accepted */
2641
2642 if (helo_required && !helo_seen)
2643 {
2644 smtp_printf("503 HELO or EHLO required\r\n");
2645 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2646 "HELO/EHLO given", host_and_ident(FALSE));
2647 break;
2648 }
2649
2650 if (sender_address != NULL)
2651 {
2652 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2653 US"sender already given");
2654 break;
2655 }
2656
2657 if (smtp_cmd_argument[0] == 0)
2658 {
2659 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2660 US"MAIL must have an address operand");
2661 break;
2662 }
2663
2664 /* Check to see if the limit for messages per connection would be
2665 exceeded by accepting further messages. */
2666
2667 if (smtp_accept_max_per_connection > 0 &&
2668 smtp_mailcmd_count > smtp_accept_max_per_connection)
2669 {
2670 smtp_printf("421 too many messages in this connection\r\n");
2671 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2672 "messages in one connection", host_and_ident(TRUE));
2673 break;
2674 }
2675
2676 /* Reset for start of message - even if this is going to fail, we
2677 obviously need to throw away any previous data. */
2678
2679 smtp_reset(reset_point);
2680 toomany = FALSE;
2681 sender_data = recipient_data = NULL;
2682
2683 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2684
2685 if (esmtp) for(;;)
2686 {
2687 uschar *name, *value, *end;
2688 unsigned long int size;
2689
2690 if (!extract_option(&name, &value)) break;
2691
2692 /* Handle SIZE= by reading the value. We don't do the check till later,
2693 in order to be able to log the sender address on failure. */
2694
2695 if (strcmpic(name, US"SIZE") == 0 &&
2696 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2697 {
2698 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2699 size = INT_MAX;
2700 message_size = (int)size;
2701 }
2702
2703 /* If this session was initiated with EHLO and accept_8bitmime is set,
2704 Exim will have indicated that it supports the BODY=8BITMIME option. In
2705 fact, it does not support this according to the RFCs, in that it does not
2706 take any special action for forwarding messages containing 8-bit
2707 characters. That is why accept_8bitmime is not the default setting, but
2708 some sites want the action that is provided. We recognize both "8BITMIME"
2709 and "7BIT" as body types, but take no action. */
2710
2711 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2712 (strcmpic(value, US"8BITMIME") == 0 ||
2713 strcmpic(value, US"7BIT") == 0)) {}
2714
2715 /* Handle the AUTH extension. If the value given is not "<>" and either
2716 the ACL says "yes" or there is no ACL but the sending host is
2717 authenticated, we set it up as the authenticated sender. However, if the
2718 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2719 the condition is met. The value of AUTH is an xtext, which means that +,
2720 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2721 coding. */
2722
2723 else if (strcmpic(name, US"AUTH") == 0)
2724 {
2725 if (Ustrcmp(value, "<>") != 0)
2726 {
2727 int rc;
2728 uschar *ignore_msg;
2729
2730 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2731 {
2732 /* Put back terminator overrides for error message */
2733 name[-1] = ' ';
2734 value[-1] = '=';
2735 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2736 US"invalid data for AUTH");
2737 goto COMMAND_LOOP;
2738 }
2739
2740 if (acl_smtp_mailauth == NULL)
2741 {
2742 ignore_msg = US"client not authenticated";
2743 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2744 }
2745 else
2746 {
2747 ignore_msg = US"rejected by ACL";
2748 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2749 &user_msg, &log_msg);
2750 }
2751
2752 switch (rc)
2753 {
2754 case OK:
2755 if (authenticated_by == NULL ||
2756 authenticated_by->mail_auth_condition == NULL ||
2757 expand_check_condition(authenticated_by->mail_auth_condition,
2758 authenticated_by->name, US"authenticator"))
2759 break; /* Accept the AUTH */
2760
2761 ignore_msg = US"server_mail_auth_condition failed";
2762 if (authenticated_id != NULL)
2763 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2764 ignore_msg, authenticated_id);
2765
2766 /* Fall through */
2767
2768 case FAIL:
2769 authenticated_sender = NULL;
2770 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2771 value, host_and_ident(TRUE), ignore_msg);
2772 break;
2773
2774 /* Should only get DEFER or ERROR here. Put back terminator
2775 overrides for error message */
2776
2777 default:
2778 name[-1] = ' ';
2779 value[-1] = '=';
2780 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2781 log_msg);
2782 goto COMMAND_LOOP;
2783 }
2784 }
2785 }
2786
2787 /* Unknown option. Stick back the terminator characters and break
2788 the loop. An error for a malformed address will occur. */
2789
2790 else
2791 {
2792 name[-1] = ' ';
2793 value[-1] = '=';
2794 break;
2795 }
2796 }
2797
2798 /* If we have passed the threshold for rate limiting, apply the current
2799 delay, and update it for next time, provided this is a limited host. */
2800
2801 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2802 verify_check_host(&smtp_ratelimit_hosts) == OK)
2803 {
2804 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2805 smtp_delay_mail/1000.0);
2806 millisleep((int)smtp_delay_mail);
2807 smtp_delay_mail *= smtp_rlm_factor;
2808 if (smtp_delay_mail > (double)smtp_rlm_limit)
2809 smtp_delay_mail = (double)smtp_rlm_limit;
2810 }
2811
2812 /* Now extract the address, first applying any SMTP-time rewriting. The
2813 TRUE flag allows "<>" as a sender address. */
2814
2815 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2816 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
2817 global_rewrite_rules) : smtp_cmd_argument;
2818
2819 /* rfc821_domains = TRUE; << no longer needed */
2820 raw_sender =
2821 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2822 TRUE);
2823 /* rfc821_domains = FALSE; << no longer needed */
2824
2825 if (raw_sender == NULL)
2826 {
2827 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
2828 break;
2829 }
2830
2831 sender_address = raw_sender;
2832
2833 /* If there is a configured size limit for mail, check that this message
2834 doesn't exceed it. The check is postponed to this point so that the sender
2835 can be logged. */
2836
2837 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2838 {
2839 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2840 log_write(L_size_reject,
2841 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2842 "message too big: size%s=%d max=%d",
2843 sender_address,
2844 host_and_ident(TRUE),
2845 (message_size == INT_MAX)? ">" : "",
2846 message_size,
2847 thismessage_size_limit);
2848 sender_address = NULL;
2849 break;
2850 }
2851
2852 /* Check there is enough space on the disk unless configured not to.
2853 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2854 plus the current message - i.e. we accept the message only if it won't
2855 reduce the space below the threshold. Add 5000 to the size to allow for
2856 overheads such as the Received: line and storing of recipients, etc.
2857 By putting the check here, even when SIZE is not given, it allow VRFY
2858 and EXPN etc. to be used when space is short. */
2859
2860 if (!receive_check_fs(
2861 (smtp_check_spool_space && message_size >= 0)?
2862 message_size + 5000 : 0))
2863 {
2864 smtp_printf("452 Space shortage, please try later\r\n");
2865 sender_address = NULL;
2866 break;
2867 }
2868
2869 /* If sender_address is unqualified, reject it, unless this is a locally
2870 generated message, or the sending host or net is permitted to send
2871 unqualified addresses - typically local machines behaving as MUAs -
2872 in which case just qualify the address. The flag is set above at the start
2873 of the SMTP connection. */
2874
2875 if (sender_domain == 0 && sender_address[0] != 0)
2876 {
2877 if (allow_unqualified_sender)
2878 {
2879 sender_domain = Ustrlen(sender_address) + 1;
2880 sender_address = rewrite_address_qualify(sender_address, FALSE);
2881 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2882 raw_sender);
2883 }
2884 else
2885 {
2886 smtp_printf("501 %s: sender address must contain a domain\r\n",
2887 smtp_cmd_argument);
2888 log_write(L_smtp_syntax_error,
2889 LOG_MAIN|LOG_REJECT,
2890 "unqualified sender rejected: <%s> %s%s",
2891 raw_sender,
2892 host_and_ident(TRUE),
2893 host_lookup_msg);
2894 sender_address = NULL;
2895 break;
2896 }
2897 }
2898
2899 /* Apply an ACL check if one is defined, before responding */
2900
2901 rc = (acl_smtp_mail == NULL)? OK :
2902 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2903
2904 if (rc == OK || rc == DISCARD)
2905 {
2906 smtp_printf("250 OK\r\n");
2907 smtp_delay_rcpt = smtp_rlr_base;
2908 recipients_discarded = (rc == DISCARD);
2909 was_rej_mail = FALSE;
2910 }
2911
2912 else
2913 {
2914 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2915 sender_address = NULL;
2916 }
2917 break;
2918
2919
2920 /* The RCPT command requires an address as an operand. All we do
2921 here is to parse it for syntactic correctness. There may be any number
2922 of RCPT commands, specifying multiple senders. We build them all into
2923 a data structure that is in argc/argv format. The start/end values
2924 given by parse_extract_address are not used, as we keep only the
2925 extracted address. */
2926
2927 case RCPT_CMD:
2928 rcpt_count++;
2929 was_rcpt = TRUE;
2930
2931 /* There must be a sender address; if the sender was rejected and
2932 pipelining was advertised, we assume the client was pipelining, and do not
2933 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2934 get the same treatment. */
2935
2936 if (sender_address == NULL)
2937 {
2938 if (pipelining_advertised && last_was_rej_mail)
2939 {
2940 smtp_printf("503 sender not yet given\r\n");
2941 was_rej_mail = TRUE;
2942 }
2943 else
2944 {
2945 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2946 US"sender not yet given");
2947 was_rcpt = FALSE; /* Not a valid RCPT */
2948 }
2949 rcpt_fail_count++;
2950 break;
2951 }
2952
2953 /* Check for an operand */
2954
2955 if (smtp_cmd_argument[0] == 0)
2956 {
2957 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2958 US"RCPT must have an address operand");
2959 rcpt_fail_count++;
2960 break;
2961 }
2962
2963 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2964 as a recipient address */
2965
2966 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2967 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
2968 global_rewrite_rules) : smtp_cmd_argument;
2969
2970 /* rfc821_domains = TRUE; << no longer needed */
2971 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2972 &recipient_domain, FALSE);
2973 /* rfc821_domains = FALSE; << no longer needed */
2974
2975 if (recipient == NULL)
2976 {
2977 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
2978 rcpt_fail_count++;
2979 break;
2980 }
2981
2982 /* If the recipient address is unqualified, reject it, unless this is a
2983 locally generated message. However, unqualified addresses are permitted
2984 from a configured list of hosts and nets - typically when behaving as
2985 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2986 really. The flag is set at the start of the SMTP connection.
2987
2988 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2989 assumed this meant "reserved local part", but the revision of RFC 821 and
2990 friends now makes it absolutely clear that it means *mailbox*. Consequently
2991 we must always qualify this address, regardless. */
2992
2993 if (recipient_domain == 0)
2994 {
2995 if (allow_unqualified_recipient ||
2996 strcmpic(recipient, US"postmaster") == 0)
2997 {
2998 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2999 recipient);
3000 recipient_domain = Ustrlen(recipient) + 1;
3001 recipient = rewrite_address_qualify(recipient, TRUE);
3002 }
3003 else
3004 {
3005 rcpt_fail_count++;
3006 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3007 smtp_cmd_argument);
3008 log_write(L_smtp_syntax_error,
3009 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3010 "<%s> %s%s", recipient, host_and_ident(TRUE),
3011 host_lookup_msg);
3012 break;
3013 }
3014 }
3015
3016 /* Check maximum allowed */
3017
3018 if (rcpt_count > recipients_max && recipients_max > 0)
3019 {
3020 if (recipients_max_reject)
3021 {
3022 rcpt_fail_count++;
3023 smtp_printf("552 too many recipients\r\n");
3024 if (!toomany)
3025 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3026 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3027 }
3028 else
3029 {
3030 rcpt_defer_count++;
3031 smtp_printf("452 too many recipients\r\n");
3032 if (!toomany)
3033 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3034 "temporarily rejected: sender=<%s> %s", sender_address,
3035 host_and_ident(TRUE));
3036 }
3037
3038 toomany = TRUE;
3039 break;
3040 }
3041
3042 /* If we have passed the threshold for rate limiting, apply the current
3043 delay, and update it for next time, provided this is a limited host. */
3044
3045 if (rcpt_count > smtp_rlr_threshold &&
3046 verify_check_host(&smtp_ratelimit_hosts) == OK)
3047 {
3048 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3049 smtp_delay_rcpt/1000.0);
3050 millisleep((int)smtp_delay_rcpt);
3051 smtp_delay_rcpt *= smtp_rlr_factor;
3052 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3053 smtp_delay_rcpt = (double)smtp_rlr_limit;
3054 }
3055
3056 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3057 for them. Otherwise, check the access control list for this recipient. */
3058
3059 rc = recipients_discarded? DISCARD :
3060 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3061
3062 /* The ACL was happy */
3063
3064 if (rc == OK)
3065 {
3066 smtp_printf("250 Accepted\r\n");
3067 receive_add_recipient(recipient, -1);
3068 }
3069
3070 /* The recipient was discarded */
3071
3072 else if (rc == DISCARD)
3073 {
3074 smtp_printf("250 Accepted\r\n");
3075 rcpt_fail_count++;
3076 discarded = TRUE;
3077 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3078 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3079 (sender_address_unrewritten != NULL)?
3080 sender_address_unrewritten : sender_address,
3081 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3082 (log_msg == NULL)? US"" : US": ",
3083 (log_msg == NULL)? US"" : log_msg);
3084 }
3085
3086 /* Either the ACL failed the address, or it was deferred. */
3087
3088 else
3089 {
3090 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3091 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3092 }
3093 break;
3094
3095
3096 /* The DATA command is legal only if it follows successful MAIL FROM
3097 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3098 not counted as a protocol error if it follows RCPT (which must have been
3099 rejected if there are no recipients.) This function is complete when a
3100 valid DATA command is encountered.
3101
3102 Note concerning the code used: RFC 2821 says this:
3103
3104 - If there was no MAIL, or no RCPT, command, or all such commands
3105 were rejected, the server MAY return a "command out of sequence"
3106 (503) or "no valid recipients" (554) reply in response to the
3107 DATA command.
3108
3109 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3110 because it is the same whether pipelining is in use or not. */
3111
3112 case DATA_CMD:
3113 if (!discarded && recipients_count <= 0)
3114 {
3115 if (pipelining_advertised && last_was_rcpt)
3116 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3117 else
3118 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3119 US"valid RCPT command must precede DATA");
3120 break;
3121 }
3122
3123 if (toomany && recipients_max_reject)
3124 {
3125 sender_address = NULL; /* This will allow a new MAIL without RSET */
3126 sender_address_unrewritten = NULL;
3127 smtp_printf("554 Too many recipients\r\n");
3128 break;
3129 }
3130
3131 if (acl_smtp_predata == NULL) rc = OK; else
3132 {
3133 enable_dollar_recipients = TRUE;
3134 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3135 &log_msg);
3136 enable_dollar_recipients = FALSE;
3137 }
3138
3139 if (rc == OK)
3140 {
3141 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3142 done = 3;
3143 message_ended = END_NOTENDED; /* Indicate in middle of data */
3144 }
3145
3146 /* Either the ACL failed the address, or it was deferred. */
3147
3148 else
3149 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3150
3151 break;
3152
3153
3154 case VRFY_CMD:
3155 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3156 if (rc != OK)
3157 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3158 else
3159 {
3160 uschar *address;
3161 uschar *s = NULL;
3162
3163 /* rfc821_domains = TRUE; << no longer needed */
3164 address = parse_extract_address(smtp_cmd_argument, &errmess, &start, &end,
3165 &recipient_domain, FALSE);
3166 /* rfc821_domains = FALSE; << no longer needed */
3167
3168 if (address == NULL)
3169 s = string_sprintf("501 %s", errmess);
3170 else
3171 {
3172 address_item *addr = deliver_make_addr(address, FALSE);
3173 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3174 -1, -1, NULL, NULL, NULL))
3175 {
3176 case OK:
3177 s = string_sprintf("250 <%s> is deliverable", address);
3178 break;
3179
3180 case DEFER:
3181 s = (addr->message != NULL)?
3182 string_sprintf("451 <%s> %s", address, addr->message) :
3183 string_sprintf("451 Cannot resolve <%s> at this time", address);
3184 break;
3185
3186 case FAIL:
3187 s = (addr->message != NULL)?
3188 string_sprintf("550 <%s> %s", address, addr->message) :
3189 string_sprintf("550 <%s> is not deliverable", address);
3190 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3191 smtp_cmd_argument, host_and_ident(TRUE));
3192 break;
3193 }
3194 }
3195
3196 smtp_printf("%s\r\n", s);
3197 }
3198 break;
3199
3200
3201 case EXPN_CMD:
3202 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3203 if (rc != OK)
3204 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3205 else
3206 {
3207 BOOL save_log_testing_mode = log_testing_mode;
3208 address_test_mode = log_testing_mode = TRUE;
3209 (void) verify_address(deliver_make_addr(smtp_cmd_argument, FALSE),
3210 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3211 NULL, NULL, NULL);
3212 address_test_mode = FALSE;
3213 log_testing_mode = save_log_testing_mode; /* true for -bh */
3214 }
3215 break;
3216
3217
3218 #ifdef SUPPORT_TLS
3219
3220 case STARTTLS_CMD:
3221 if (!tls_advertised)
3222 {
3223 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3224 US"STARTTLS command used when not advertised");
3225 break;
3226 }
3227
3228 /* Apply an ACL check if one is defined */
3229
3230 if (acl_smtp_starttls != NULL)
3231 {
3232 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3233 &log_msg);
3234 if (rc != OK)
3235 {
3236 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3237 break;
3238 }
3239 }
3240
3241 /* RFC 2487 is not clear on when this command may be sent, though it
3242 does state that all information previously obtained from the client
3243 must be discarded if a TLS session is started. It seems reasonble to
3244 do an implied RSET when STARTTLS is received. */
3245
3246 incomplete_transaction_log(US"STARTTLS");
3247 smtp_reset(reset_point);
3248 toomany = FALSE;
3249 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3250
3251 /* Attempt to start up a TLS session, and if successful, discard all
3252 knowledge that was obtained previously. At least, that's what the RFC says,
3253 and that's what happens by default. However, in order to work round YAEB,
3254 there is an option to remember the esmtp state. Sigh.
3255
3256 We must allow for an extra EHLO command and an extra AUTH command after
3257 STARTTLS that don't add to the nonmail command count. */
3258
3259 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3260 {
3261 if (!tls_remember_esmtp)
3262 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3263 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3264 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3265 if (sender_helo_name != NULL)
3266 {
3267 store_free(sender_helo_name);
3268 sender_helo_name = NULL;
3269 host_build_sender_fullhost(); /* Rebuild */
3270 set_process_info("handling incoming TLS connection from %s",
3271 host_and_ident(FALSE));
3272 }
3273 received_protocol = (esmtp?
3274 protocols[pextend + pcrpted +
3275 ((sender_host_authenticated != NULL)? pauthed : 0)]
3276 :
3277 protocols[pnormal + pcrpted])
3278 +
3279 ((sender_host_address != NULL)? pnlocal : 0);
3280
3281 sender_host_authenticated = NULL;
3282 authenticated_id = NULL;
3283 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3284 DEBUG(D_tls) debug_printf("TLS active\n");
3285 break; /* Successful STARTTLS */
3286 }
3287
3288 /* Some local configuration problem was discovered before actually trying
3289 to do a TLS handshake; give a temporary error. */
3290
3291 else if (rc == DEFER)
3292 {
3293 smtp_printf("454 TLS currently unavailable\r\n");
3294 break;
3295 }
3296
3297 /* Hard failure. Reject everything except QUIT or closed connection. One
3298 cause for failure is a nested STARTTLS, in which case tls_active remains
3299 set, but we must still reject all incoming commands. */
3300
3301 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3302 while (done <= 0)
3303 {
3304 switch(smtp_read_command(FALSE))
3305 {
3306 case EOF_CMD:
3307 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3308 smtp_get_connection_info());
3309 done = 2;
3310 break;
3311
3312 case QUIT_CMD:
3313 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3314 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3315 smtp_get_connection_info());
3316 done = 2;
3317 break;
3318
3319 default:
3320 smtp_printf("554 Security failure\r\n");
3321 break;
3322 }
3323 }
3324 tls_close(TRUE);
3325 break;
3326 #endif
3327
3328
3329 /* The ACL for QUIT is provided for gathering statistical information or
3330 similar; it does not affect the response code, but it can supply a custom
3331 message. */
3332
3333 case QUIT_CMD:
3334 incomplete_transaction_log(US"QUIT");
3335
3336 if (acl_smtp_quit != NULL)
3337 {
3338 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit,&user_msg,&log_msg);
3339 if (rc == ERROR)
3340 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3341 log_msg);
3342 }
3343 else user_msg = NULL;
3344
3345 if (user_msg == NULL)
3346 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3347 else
3348 smtp_printf("221 %s\r\n", user_msg);
3349
3350 #ifdef SUPPORT_TLS
3351 tls_close(TRUE);
3352 #endif
3353
3354 done = 2;
3355 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3356 smtp_get_connection_info());
3357 break;
3358
3359
3360 case RSET_CMD:
3361 incomplete_transaction_log(US"RSET");
3362 smtp_reset(reset_point);
3363 toomany = FALSE;
3364 smtp_printf("250 Reset OK\r\n");
3365 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3366 break;
3367
3368
3369 case NOOP_CMD:
3370 smtp_printf("250 OK\r\n");
3371 break;
3372
3373
3374 /* Show ETRN/EXPN/VRFY if there's
3375 an ACL for checking hosts; if actually used, a check will be done for
3376 permitted hosts. */
3377
3378 case HELP_CMD:
3379 smtp_printf("214-Commands supported:\r\n");
3380 {
3381 uschar buffer[256];
3382 buffer[0] = 0;
3383 Ustrcat(buffer, " AUTH");
3384 #ifdef SUPPORT_TLS
3385 Ustrcat(buffer, " STARTTLS");
3386 #endif
3387 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3388 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3389 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3390 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3391 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3392 smtp_printf("214%s\r\n", buffer);
3393 }
3394 break;
3395
3396
3397 case EOF_CMD:
3398 incomplete_transaction_log(US"connection lost");
3399 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3400
3401 /* Don't log by default unless in the middle of a message, as some mailers
3402 just drop the call rather than sending QUIT, and it clutters up the logs.
3403 */
3404
3405 if (sender_address != NULL || recipients_count > 0)
3406 log_write(L_lost_incoming_connection,
3407 LOG_MAIN,
3408 "unexpected %s while reading SMTP command from %s%s",
3409 sender_host_unknown? "EOF" : "disconnection",
3410 host_and_ident(FALSE), smtp_read_error);
3411
3412 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3413 smtp_get_connection_info(), smtp_read_error);
3414
3415 done = 1;
3416 break;
3417
3418
3419 case ETRN_CMD:
3420 if (sender_address != NULL)
3421 {
3422 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3423 US"ETRN is not permitted inside a transaction");
3424 break;
3425 }
3426
3427 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
3428 host_and_ident(FALSE));
3429
3430 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
3431 if (rc != OK)
3432 {
3433 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3434 break;
3435 }
3436
3437 /* Compute the serialization key for this command. */
3438
3439 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_argument);
3440
3441 /* If a command has been specified for running as a result of ETRN, we
3442 permit any argument to ETRN. If not, only the # standard form is permitted,
3443 since that is strictly the only kind of ETRN that can be implemented
3444 according to the RFC. */
3445
3446 if (smtp_etrn_command != NULL)
3447 {
3448 uschar *error;
3449 BOOL rc;
3450 etrn_command = smtp_etrn_command;
3451 deliver_domain = smtp_cmd_argument;
3452 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3453 US"ETRN processing", &error);
3454 deliver_domain = NULL;
3455 if (!rc)
3456 {
3457 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3458 error);
3459 smtp_printf("458 Internal failure\r\n");
3460 break;
3461 }
3462 }
3463
3464 /* Else set up to call Exim with the -R option. */
3465
3466 else
3467 {
3468 if (*smtp_cmd_argument++ != '#')
3469 {
3470 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3471 US"argument must begin with #");
3472 break;
3473 }
3474 etrn_command = US"exim -R";
3475 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3476 smtp_cmd_argument);
3477 }
3478
3479 /* If we are host-testing, don't actually do anything. */
3480
3481 if (host_checking)
3482 {
3483 HDEBUG(D_any)
3484 {
3485 debug_printf("ETRN command is: %s\n", etrn_command);
3486 debug_printf("ETRN command execution skipped\n");
3487 }
3488 smtp_printf("250 OK\r\n");
3489 break;
3490 }
3491
3492
3493 /* If ETRN queue runs are to be serialized, check the database to
3494 ensure one isn't already running. */
3495
3496 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3497 {
3498 smtp_printf("458 Already processing %s\r\n", smtp_cmd_argument);
3499 break;
3500 }
3501
3502 /* Fork a child process and run the command. We don't want to have to
3503 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3504 forking. It should be set that way anyway for external incoming SMTP,
3505 but we save and restore to be tidy. If serialization is required, we
3506 actually run the command in yet another process, so we can wait for it
3507 to complete and then remove the serialization lock. */
3508
3509 oldsignal = signal(SIGCHLD, SIG_IGN);
3510
3511 if ((pid = fork()) == 0)
3512 {