Fix "(during SMTP connection from NULL)" bug.
[exim.git] / src / src / smtp_in.c
1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.32 2006/02/13 16:23:57 ph10 Exp $ */
2
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
6
7 /* Copyright (c) University of Cambridge 1995 - 2006 */
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 If sender_fullhost is NULL, we are at a very early stage of the connection;
630 just use the IP address.
631
632 Argument: none
633 Returns: a string describing the connection
634 */
635
636 uschar *
637 smtp_get_connection_info(void)
638 {
639 uschar *hostname = (sender_fullhost == NULL)?
640 sender_host_address : sender_fullhost;
641
642 if (host_checking)
643 return string_sprintf("SMTP connection from %s", hostname);
644
645 if (sender_host_unknown || sender_host_notsocket)
646 return string_sprintf("SMTP connection from %s", sender_ident);
647
648 if (is_inetd)
649 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
650
651 if ((log_extra_selector & LX_incoming_interface) != 0 &&
652 interface_address != NULL)
653 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
654 interface_address, interface_port);
655
656 return string_sprintf("SMTP connection from %s", hostname);
657 }
658
659
660
661 /*************************************************
662 * Check HELO line and set sender_helo_name *
663 *************************************************/
664
665 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
666 the domain name of the sending host, or an ip literal in square brackets. The
667 arrgument is placed in sender_helo_name, which is in malloc store, because it
668 must persist over multiple incoming messages. If helo_accept_junk is set, this
669 host is permitted to send any old junk (needed for some broken hosts).
670 Otherwise, helo_allow_chars can be used for rogue characters in general
671 (typically people want to let in underscores).
672
673 Argument:
674 s the data portion of the line (already past any white space)
675
676 Returns: TRUE or FALSE
677 */
678
679 static BOOL
680 check_helo(uschar *s)
681 {
682 uschar *start = s;
683 uschar *end = s + Ustrlen(s);
684 BOOL yield = helo_accept_junk;
685
686 /* Discard any previous helo name */
687
688 if (sender_helo_name != NULL)
689 {
690 store_free(sender_helo_name);
691 sender_helo_name = NULL;
692 }
693
694 /* Skip tests if junk is permitted. */
695
696 if (!yield)
697 {
698 /* Allow the new standard form for IPv6 address literals, namely,
699 [IPv6:....], and because someone is bound to use it, allow an equivalent
700 IPv4 form. Allow plain addresses as well. */
701
702 if (*s == '[')
703 {
704 if (end[-1] == ']')
705 {
706 end[-1] = 0;
707 if (strncmpic(s, US"[IPv6:", 6) == 0)
708 yield = (string_is_ip_address(s+6, NULL) == 6);
709 else if (strncmpic(s, US"[IPv4:", 6) == 0)
710 yield = (string_is_ip_address(s+6, NULL) == 4);
711 else
712 yield = (string_is_ip_address(s+1, NULL) != 0);
713 end[-1] = ']';
714 }
715 }
716
717 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
718 that have been configured (usually underscore - sigh). */
719
720 else if (*s != 0)
721 {
722 yield = TRUE;
723 while (*s != 0)
724 {
725 if (!isalnum(*s) && *s != '.' && *s != '-' &&
726 Ustrchr(helo_allow_chars, *s) == NULL)
727 {
728 yield = FALSE;
729 break;
730 }
731 s++;
732 }
733 }
734 }
735
736 /* Save argument if OK */
737
738 if (yield) sender_helo_name = string_copy_malloc(start);
739 return yield;
740 }
741
742
743
744
745
746 /*************************************************
747 * Extract SMTP command option *
748 *************************************************/
749
750 /* This function picks the next option setting off the end of smtp_cmd_argument. It
751 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
752 things that can appear there.
753
754 Arguments:
755 name point this at the name
756 value point this at the data string
757
758 Returns: TRUE if found an option
759 */
760
761 static BOOL
762 extract_option(uschar **name, uschar **value)
763 {
764 uschar *n;
765 uschar *v = smtp_cmd_argument + Ustrlen(smtp_cmd_argument) -1;
766 while (isspace(*v)) v--;
767 v[1] = 0;
768
769 while (v > smtp_cmd_argument && *v != '=' && !isspace(*v)) v--;
770 if (*v != '=') return FALSE;
771
772 n = v;
773 while(isalpha(n[-1])) n--;
774
775 if (n[-1] != ' ') return FALSE;
776
777 n[-1] = 0;
778 *name = n;
779 *v++ = 0;
780 *value = v;
781 return TRUE;
782 }
783
784
785
786
787
788
789
790 /*************************************************
791 * Reset for new message *
792 *************************************************/
793
794 /* This function is called whenever the SMTP session is reset from
795 within either of the setup functions.
796
797 Argument: the stacking pool storage reset point
798 Returns: nothing
799 */
800
801 static void
802 smtp_reset(void *reset_point)
803 {
804 int i;
805 store_reset(reset_point);
806 recipients_list = NULL;
807 rcpt_count = rcpt_defer_count = rcpt_fail_count =
808 raw_recipients_count = recipients_count = recipients_list_max = 0;
809 message_linecount = 0;
810 message_size = -1;
811 acl_warn_headers = NULL;
812 queue_only_policy = FALSE;
813 deliver_freeze = FALSE; /* Can be set by ACL */
814 freeze_tell = freeze_tell_config; /* Can be set by ACL */
815 fake_response = OK; /* Can be set by ACL */
816 #ifdef WITH_CONTENT_SCAN
817 no_mbox_unspool = FALSE; /* Can be set by ACL */
818 #endif
819 submission_mode = FALSE; /* Can be set by ACL */
820 suppress_local_fixups = FALSE; /* Can be set by ACL */
821 active_local_from_check = local_from_check; /* Can be set by ACL */
822 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
823 sender_address = NULL;
824 submission_name = NULL; /* Can be set by ACL */
825 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
826 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
827 sender_verified_list = NULL; /* No senders verified */
828 memset(sender_address_cache, 0, sizeof(sender_address_cache));
829 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
830 authenticated_sender = NULL;
831 #ifdef EXPERIMENTAL_BRIGHTMAIL
832 bmi_run = 0;
833 bmi_verdicts = NULL;
834 #endif
835 #ifdef EXPERIMENTAL_DOMAINKEYS
836 dk_do_verify = 0;
837 #endif
838 #ifdef EXPERIMENTAL_SPF
839 spf_header_comment = NULL;
840 spf_received = NULL;
841 spf_result = NULL;
842 spf_smtp_comment = NULL;
843 #endif
844 body_linecount = body_zerocount = 0;
845
846 sender_rate = sender_rate_limit = sender_rate_period = NULL;
847 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
848 /* Note that ratelimiters_conn persists across resets. */
849
850 /* The message variables follow the connection variables. */
851
852 for (i = 0; i < ACL_MVARS; i++) acl_var[ACL_CVARS + i] = NULL;
853
854 /* The message body variables use malloc store. They may be set if this is
855 not the first message in an SMTP session and the previous message caused them
856 to be referenced in an ACL. */
857
858 if (message_body != NULL)
859 {
860 store_free(message_body);
861 message_body = NULL;
862 }
863
864 if (message_body_end != NULL)
865 {
866 store_free(message_body_end);
867 message_body_end = NULL;
868 }
869
870 /* Warning log messages are also saved in malloc store. They are saved to avoid
871 repetition in the same message, but it seems right to repeat them for different
872 messagess. */
873
874 while (acl_warn_logged != NULL)
875 {
876 string_item *this = acl_warn_logged;
877 acl_warn_logged = acl_warn_logged->next;
878 store_free(this);
879 }
880 }
881
882
883
884
885
886 /*************************************************
887 * Initialize for incoming batched SMTP message *
888 *************************************************/
889
890 /* This function is called from smtp_setup_msg() in the case when
891 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
892 of messages in one file with SMTP commands between them. All errors must be
893 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
894 relevant. After an error on a sender, or an invalid recipient, the remainder
895 of the message is skipped. The value of received_protocol is already set.
896
897 Argument: none
898 Returns: > 0 message successfully started (reached DATA)
899 = 0 QUIT read or end of file reached
900 < 0 should not occur
901 */
902
903 static int
904 smtp_setup_batch_msg(void)
905 {
906 int done = 0;
907 void *reset_point = store_get(0);
908
909 /* Save the line count at the start of each transaction - single commands
910 like HELO and RSET count as whole transactions. */
911
912 bsmtp_transaction_linecount = receive_linecount;
913
914 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
915
916 smtp_reset(reset_point); /* Reset for start of message */
917
918 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
919 value. The values are 2 larger than the required yield of the function. */
920
921 while (done <= 0)
922 {
923 uschar *errmess;
924 uschar *recipient = NULL;
925 int start, end, sender_domain, recipient_domain;
926
927 switch(smtp_read_command(FALSE))
928 {
929 /* The HELO/EHLO commands set sender_address_helo if they have
930 valid data; otherwise they are ignored, except that they do
931 a reset of the state. */
932
933 case HELO_CMD:
934 case EHLO_CMD:
935
936 check_helo(smtp_cmd_argument);
937 /* Fall through */
938
939 case RSET_CMD:
940 smtp_reset(reset_point);
941 bsmtp_transaction_linecount = receive_linecount;
942 break;
943
944
945 /* The MAIL FROM command requires an address as an operand. All we
946 do here is to parse it for syntactic correctness. The form "<>" is
947 a special case which converts into an empty string. The start/end
948 pointers in the original are not used further for this address, as
949 it is the canonical extracted address which is all that is kept. */
950
951 case MAIL_CMD:
952 if (sender_address != NULL)
953 /* The function moan_smtp_batch() does not return. */
954 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
955
956 if (smtp_cmd_argument[0] == 0)
957 /* The function moan_smtp_batch() does not return. */
958 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
959
960 /* Reset to start of message */
961
962 smtp_reset(reset_point);
963
964 /* Apply SMTP rewrite */
965
966 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
967 rewrite_one(smtp_cmd_argument, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
968 US"", global_rewrite_rules) : smtp_cmd_argument;
969
970 /* Extract the address; the TRUE flag allows <> as valid */
971
972 raw_sender =
973 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
974 TRUE);
975
976 if (raw_sender == NULL)
977 /* The function moan_smtp_batch() does not return. */
978 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
979
980 sender_address = string_copy(raw_sender);
981
982 /* Qualify unqualified sender addresses if permitted to do so. */
983
984 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
985 {
986 if (allow_unqualified_sender)
987 {
988 sender_address = rewrite_address_qualify(sender_address, FALSE);
989 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
990 "and rewritten\n", raw_sender);
991 }
992 /* The function moan_smtp_batch() does not return. */
993 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
994 "a domain");
995 }
996 break;
997
998
999 /* The RCPT TO command requires an address as an operand. All we do
1000 here is to parse it for syntactic correctness. There may be any number
1001 of RCPT TO commands, specifying multiple senders. We build them all into
1002 a data structure that is in argc/argv format. The start/end values
1003 given by parse_extract_address are not used, as we keep only the
1004 extracted address. */
1005
1006 case RCPT_CMD:
1007 if (sender_address == NULL)
1008 /* The function moan_smtp_batch() does not return. */
1009 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1010
1011 if (smtp_cmd_argument[0] == 0)
1012 /* The function moan_smtp_batch() does not return. */
1013 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1014
1015 /* Check maximum number allowed */
1016
1017 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1018 /* The function moan_smtp_batch() does not return. */
1019 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1020 recipients_max_reject? "552": "452");
1021
1022 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1023 recipient address */
1024
1025 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1026 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
1027 global_rewrite_rules) : smtp_cmd_argument;
1028
1029 /* rfc821_domains = TRUE; << no longer needed */
1030 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1031 &recipient_domain, FALSE);
1032 /* rfc821_domains = FALSE; << no longer needed */
1033
1034 if (recipient == NULL)
1035 /* The function moan_smtp_batch() does not return. */
1036 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1037
1038 /* If the recipient address is unqualified, qualify it if permitted. Then
1039 add it to the list of recipients. */
1040
1041 if (recipient_domain == 0)
1042 {
1043 if (allow_unqualified_recipient)
1044 {
1045 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1046 recipient);
1047 recipient = rewrite_address_qualify(recipient, TRUE);
1048 }
1049 /* The function moan_smtp_batch() does not return. */
1050 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1051 "a domain");
1052 }
1053 receive_add_recipient(recipient, -1);
1054 break;
1055
1056
1057 /* The DATA command is legal only if it follows successful MAIL FROM
1058 and RCPT TO commands. This function is complete when a valid DATA
1059 command is encountered. */
1060
1061 case DATA_CMD:
1062 if (sender_address == NULL || recipients_count <= 0)
1063 {
1064 /* The function moan_smtp_batch() does not return. */
1065 if (sender_address == NULL)
1066 moan_smtp_batch(smtp_cmd_buffer,
1067 "503 MAIL FROM:<sender> command must precede DATA");
1068 else
1069 moan_smtp_batch(smtp_cmd_buffer,
1070 "503 RCPT TO:<recipient> must precede DATA");
1071 }
1072 else
1073 {
1074 done = 3; /* DATA successfully achieved */
1075 message_ended = END_NOTENDED; /* Indicate in middle of message */
1076 }
1077 break;
1078
1079
1080 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1081
1082 case VRFY_CMD:
1083 case EXPN_CMD:
1084 case HELP_CMD:
1085 case NOOP_CMD:
1086 case ETRN_CMD:
1087 bsmtp_transaction_linecount = receive_linecount;
1088 break;
1089
1090
1091 case EOF_CMD:
1092 case QUIT_CMD:
1093 done = 2;
1094 break;
1095
1096
1097 case BADARG_CMD:
1098 /* The function moan_smtp_batch() does not return. */
1099 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1100 break;
1101
1102
1103 case BADCHAR_CMD:
1104 /* The function moan_smtp_batch() does not return. */
1105 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1106 break;
1107
1108
1109 default:
1110 /* The function moan_smtp_batch() does not return. */
1111 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1112 break;
1113 }
1114 }
1115
1116 return done - 2; /* Convert yield values */
1117 }
1118
1119
1120
1121
1122 /*************************************************
1123 * Start an SMTP session *
1124 *************************************************/
1125
1126 /* This function is called at the start of an SMTP session. Thereafter,
1127 smtp_setup_msg() is called to initiate each separate message. This
1128 function does host-specific testing, and outputs the banner line.
1129
1130 Arguments: none
1131 Returns: FALSE if the session can not continue; something has
1132 gone wrong, or the connection to the host is blocked
1133 */
1134
1135 BOOL
1136 smtp_start_session(void)
1137 {
1138 int size = 256;
1139 int i, ptr;
1140 uschar *p, *s, *ss;
1141
1142 /* Default values for certain variables */
1143
1144 helo_seen = esmtp = helo_accept_junk = FALSE;
1145 count_nonmail = TRUE_UNSET;
1146 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1147 smtp_delay_mail = smtp_rlm_base;
1148 auth_advertised = FALSE;
1149 pipelining_advertised = FALSE;
1150 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1151
1152 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1153
1154 sender_host_authenticated = NULL;
1155 authenticated_by = NULL;
1156
1157 #ifdef SUPPORT_TLS
1158 tls_cipher = tls_peerdn = NULL;
1159 tls_advertised = FALSE;
1160 #endif
1161
1162 /* Reset ACL connection variables */
1163
1164 for (i = 0; i < ACL_CVARS; i++) acl_var[i] = NULL;
1165
1166 /* Allow for trailing 0 in the command buffer. */
1167
1168 smtp_cmd_buffer = (uschar *)malloc(smtp_cmd_buffer_size + 1);
1169 if (smtp_cmd_buffer == NULL)
1170 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1171 "malloc() failed for SMTP command buffer");
1172
1173 /* For batched input, the protocol setting can be overridden from the
1174 command line by a trusted caller. */
1175
1176 if (smtp_batched_input)
1177 {
1178 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1179 }
1180
1181 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1182 reset later if any of EHLO/AUTH/STARTTLS are received. */
1183
1184 else
1185 received_protocol =
1186 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1187
1188 /* Set up the buffer for inputting using direct read() calls, and arrange to
1189 call the local functions instead of the standard C ones. */
1190
1191 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1192 if (smtp_inbuffer == NULL)
1193 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1194 receive_getc = smtp_getc;
1195 receive_ungetc = smtp_ungetc;
1196 receive_feof = smtp_feof;
1197 receive_ferror = smtp_ferror;
1198 smtp_inptr = smtp_inend = smtp_inbuffer;
1199 smtp_had_eof = smtp_had_error = 0;
1200
1201 /* Set up the message size limit; this may be host-specific */
1202
1203 thismessage_size_limit = expand_string_integer(message_size_limit);
1204 if (thismessage_size_limit < 0)
1205 {
1206 if (thismessage_size_limit == -1)
1207 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1208 "%s", expand_string_message);
1209 else
1210 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1211 "%s", expand_string_message);
1212 smtp_closedown(US"Temporary local problem - please try later");
1213 return FALSE;
1214 }
1215
1216 /* When a message is input locally via the -bs or -bS options, sender_host_
1217 unknown is set unless -oMa was used to force an IP address, in which case it
1218 is checked like a real remote connection. When -bs is used from inetd, this
1219 flag is not set, causing the sending host to be checked. The code that deals
1220 with IP source routing (if configured) is never required for -bs or -bS and
1221 the flag sender_host_notsocket is used to suppress it.
1222
1223 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1224 reserve for certain hosts and/or networks. */
1225
1226 if (!sender_host_unknown)
1227 {
1228 int rc;
1229 BOOL reserved_host = FALSE;
1230
1231 /* Look up IP options (source routing info) on the socket if this is not an
1232 -oMa "host", and if any are found, log them and drop the connection.
1233
1234 Linux (and others now, see below) is different to everyone else, so there
1235 has to be some conditional compilation here. Versions of Linux before 2.1.15
1236 used a structure whose name was "options". Somebody finally realized that
1237 this name was silly, and it got changed to "ip_options". I use the
1238 newer name here, but there is a fudge in the script that sets up os.h
1239 to define a macro in older Linux systems.
1240
1241 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1242 glibc 2, which has chosen ip_opts for the structure name. This is now
1243 really a glibc thing rather than a Linux thing, so the condition name
1244 has been changed to reflect this. It is relevant also to GNU/Hurd.
1245
1246 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1247 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1248 a special macro defined in the os.h file.
1249
1250 Some DGUX versions on older hardware appear not to support IP options at
1251 all, so there is now a general macro which can be set to cut out this
1252 support altogether.
1253
1254 How to do this properly in IPv6 is not yet known. */
1255
1256 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1257
1258 #ifdef GLIBC_IP_OPTIONS
1259 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1260 #define OPTSTYLE 1
1261 #else
1262 #define OPTSTYLE 2
1263 #endif
1264 #elif defined DARWIN_IP_OPTIONS
1265 #define OPTSTYLE 2
1266 #else
1267 #define OPTSTYLE 3
1268 #endif
1269
1270 if (!host_checking && !sender_host_notsocket)
1271 {
1272 #if OPTSTYLE == 1
1273 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1274 struct ip_options *ipopt = store_get(optlen);
1275 #elif OPTSTYLE == 2
1276 struct ip_opts ipoptblock;
1277 struct ip_opts *ipopt = &ipoptblock;
1278 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1279 #else
1280 struct ipoption ipoptblock;
1281 struct ipoption *ipopt = &ipoptblock;
1282 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1283 #endif
1284
1285 /* Occasional genuine failures of getsockopt() have been seen - for
1286 example, "reset by peer". Therefore, just log and give up on this
1287 call, unless the error is ENOPROTOOPT. This error is given by systems
1288 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1289 of writing. So for that error, carry on - we just can't do an IP options
1290 check. */
1291
1292 DEBUG(D_receive) debug_printf("checking for IP options\n");
1293
1294 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1295 &optlen) < 0)
1296 {
1297 if (errno != ENOPROTOOPT)
1298 {
1299 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1300 host_and_ident(FALSE), strerror(errno));
1301 smtp_printf("451 SMTP service not available\r\n");
1302 return FALSE;
1303 }
1304 }
1305
1306 /* Deal with any IP options that are set. On the systems I have looked at,
1307 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1308 more logging data than will fit in big_buffer. Nevertheless, after somebody
1309 questioned this code, I've added in some paranoid checking. */
1310
1311 else if (optlen > 0)
1312 {
1313 uschar *p = big_buffer;
1314 uschar *pend = big_buffer + big_buffer_size;
1315 uschar *opt, *adptr;
1316 int optcount;
1317 struct in_addr addr;
1318
1319 #if OPTSTYLE == 1
1320 uschar *optstart = (uschar *)(ipopt->__data);
1321 #elif OPTSTYLE == 2
1322 uschar *optstart = (uschar *)(ipopt->ip_opts);
1323 #else
1324 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1325 #endif
1326
1327 DEBUG(D_receive) debug_printf("IP options exist\n");
1328
1329 Ustrcpy(p, "IP options on incoming call:");
1330 p += Ustrlen(p);
1331
1332 for (opt = optstart; opt != NULL &&
1333 opt < (uschar *)(ipopt) + optlen;)
1334 {
1335 switch (*opt)
1336 {
1337 case IPOPT_EOL:
1338 opt = NULL;
1339 break;
1340
1341 case IPOPT_NOP:
1342 opt++;
1343 break;
1344
1345 case IPOPT_SSRR:
1346 case IPOPT_LSRR:
1347 if (!string_format(p, pend-p, " %s [@%s",
1348 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1349 #if OPTSTYLE == 1
1350 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1351 #elif OPTSTYLE == 2
1352 inet_ntoa(ipopt->ip_dst)))
1353 #else
1354 inet_ntoa(ipopt->ipopt_dst)))
1355 #endif
1356 {
1357 opt = NULL;
1358 break;
1359 }
1360
1361 p += Ustrlen(p);
1362 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1363 adptr = opt + 3;
1364 while (optcount-- > 0)
1365 {
1366 memcpy(&addr, adptr, sizeof(addr));
1367 if (!string_format(p, pend - p - 1, "%s%s",
1368 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1369 {
1370 opt = NULL;
1371 break;
1372 }
1373 p += Ustrlen(p);
1374 adptr += sizeof(struct in_addr);
1375 }
1376 *p++ = ']';
1377 opt += opt[1];
1378 break;
1379
1380 default:
1381 {
1382 int i;
1383 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1384 Ustrcat(p, "[ ");
1385 p += 2;
1386 for (i = 0; i < opt[1]; i++)
1387 {
1388 sprintf(CS p, "%2.2x ", opt[i]);
1389 p += 3;
1390 }
1391 *p++ = ']';
1392 }
1393 opt += opt[1];
1394 break;
1395 }
1396 }
1397
1398 *p = 0;
1399 log_write(0, LOG_MAIN, "%s", big_buffer);
1400
1401 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1402
1403 log_write(0, LOG_MAIN|LOG_REJECT,
1404 "connection from %s refused (IP options)", host_and_ident(FALSE));
1405
1406 smtp_printf("554 SMTP service not available\r\n");
1407 return FALSE;
1408 }
1409
1410 /* Length of options = 0 => there are no options */
1411
1412 else DEBUG(D_receive) debug_printf("no IP options found\n");
1413 }
1414 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1415
1416 /* Set keep-alive in socket options. The option is on by default. This
1417 setting is an attempt to get rid of some hanging connections that stick in
1418 read() when the remote end (usually a dialup) goes away. */
1419
1420 if (smtp_accept_keepalive && !sender_host_notsocket)
1421 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1422
1423 /* If the current host matches host_lookup, set the name by doing a
1424 reverse lookup. On failure, sender_host_name will be NULL and
1425 host_lookup_failed will be TRUE. This may or may not be serious - optional
1426 checks later. */
1427
1428 if (verify_check_host(&host_lookup) == OK)
1429 {
1430 (void)host_name_lookup();
1431 host_build_sender_fullhost();
1432 }
1433
1434 /* Delay this until we have the full name, if it is looked up. */
1435
1436 set_process_info("handling incoming connection from %s",
1437 host_and_ident(FALSE));
1438
1439 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1440 smtps port for use with older style SSL MTAs. */
1441
1442 #ifdef SUPPORT_TLS
1443 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1444 return FALSE;
1445 #endif
1446
1447 /* Test for explicit connection rejection */
1448
1449 if (verify_check_host(&host_reject_connection) == OK)
1450 {
1451 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1452 "from %s (host_reject_connection)", host_and_ident(FALSE));
1453 smtp_printf("554 SMTP service not available\r\n");
1454 return FALSE;
1455 }
1456
1457 /* Test with TCP Wrappers if so configured */
1458
1459 #ifdef USE_TCP_WRAPPERS
1460 if (!hosts_ctl("exim",
1461 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1462 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1463 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1464 {
1465 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1466 log_write(L_connection_reject,
1467 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1468 "(tcp wrappers)", host_and_ident(FALSE));
1469 smtp_printf("554 SMTP service not available\r\n");
1470 return FALSE;
1471 }
1472 #endif
1473
1474 /* Check for reserved slots. Note that the count value doesn't include
1475 this process, as it gets upped in the parent process. */
1476
1477 if (smtp_accept_max > 0 &&
1478 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1479 {
1480 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1481 {
1482 log_write(L_connection_reject,
1483 LOG_MAIN, "temporarily refused connection from %s: not in "
1484 "reserve list: connected=%d max=%d reserve=%d%s",
1485 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1486 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1487 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1488 "please try again later\r\n", smtp_active_hostname);
1489 return FALSE;
1490 }
1491 reserved_host = TRUE;
1492 }
1493
1494 /* If a load level above which only messages from reserved hosts are
1495 accepted is set, check the load. For incoming calls via the daemon, the
1496 check is done in the superior process if there are no reserved hosts, to
1497 save a fork. In all cases, the load average will already be available
1498 in a global variable at this point. */
1499
1500 if (smtp_load_reserve >= 0 &&
1501 load_average > smtp_load_reserve &&
1502 !reserved_host &&
1503 verify_check_host(&smtp_reserve_hosts) != OK)
1504 {
1505 log_write(L_connection_reject,
1506 LOG_MAIN, "temporarily refused connection from %s: not in "
1507 "reserve list and load average = %.2f", host_and_ident(FALSE),
1508 (double)load_average/1000.0);
1509 smtp_printf("421 %s: Too much load; please try again later\r\n",
1510 smtp_active_hostname);
1511 return FALSE;
1512 }
1513
1514 /* Determine whether unqualified senders or recipients are permitted
1515 for this host. Unfortunately, we have to do this every time, in order to
1516 set the flags so that they can be inspected when considering qualifying
1517 addresses in the headers. For a site that permits no qualification, this
1518 won't take long, however. */
1519
1520 allow_unqualified_sender =
1521 verify_check_host(&sender_unqualified_hosts) == OK;
1522
1523 allow_unqualified_recipient =
1524 verify_check_host(&recipient_unqualified_hosts) == OK;
1525
1526 /* Determine whether HELO/EHLO is required for this host. The requirement
1527 can be hard or soft. */
1528
1529 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1530 if (!helo_required)
1531 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1532
1533 /* Determine whether this hosts is permitted to send syntactic junk
1534 after a HELO or EHLO command. */
1535
1536 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1537 }
1538
1539 /* For batch SMTP input we are now done. */
1540
1541 if (smtp_batched_input) return TRUE;
1542
1543 /* Run the ACL if it exists */
1544
1545 if (acl_smtp_connect != NULL)
1546 {
1547 int rc;
1548 uschar *user_msg, *log_msg;
1549 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1550 &log_msg);
1551 if (rc != OK)
1552 {
1553 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1554 return FALSE;
1555 }
1556 }
1557
1558 /* Output the initial message for a two-way SMTP connection. It may contain
1559 newlines, which then cause a multi-line response to be given. */
1560
1561 s = expand_string(smtp_banner);
1562 if (s == NULL)
1563 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1564 "failed: %s", smtp_banner, expand_string_message);
1565
1566 /* Remove any terminating newlines; might as well remove trailing space too */
1567
1568 p = s + Ustrlen(s);
1569 while (p > s && isspace(p[-1])) p--;
1570 *p = 0;
1571
1572 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1573 is all contained in a single IP packet. The original code wrote out the
1574 greeting using several calls to fprint/fputc, and on busy servers this could
1575 cause it to be split over more than one packet - which caused CC:Mail to fall
1576 over when it got the second part of the greeting after sending its first
1577 command. Sigh. To try to avoid this, build the complete greeting message
1578 first, and output it in one fell swoop. This gives a better chance of it
1579 ending up as a single packet. */
1580
1581 ss = store_get(size);
1582 ptr = 0;
1583
1584 p = s;
1585 do /* At least once, in case we have an empty string */
1586 {
1587 int len;
1588 uschar *linebreak = Ustrchr(p, '\n');
1589 if (linebreak == NULL)
1590 {
1591 len = Ustrlen(p);
1592 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1593 }
1594 else
1595 {
1596 len = linebreak - p;
1597 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1598 }
1599 ss = string_cat(ss, &size, &ptr, p, len);
1600 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1601 p += len;
1602 if (linebreak != NULL) p++;
1603 }
1604 while (*p != 0);
1605
1606 ss[ptr] = 0; /* string_cat leaves room for this */
1607
1608 /* Before we write the banner, check that there is no input pending, unless
1609 this synchronisation check is disabled. */
1610
1611 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1612 {
1613 fd_set fds;
1614 struct timeval tzero;
1615 tzero.tv_sec = 0;
1616 tzero.tv_usec = 0;
1617 FD_ZERO(&fds);
1618 FD_SET(fileno(smtp_in), &fds);
1619 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1620 &tzero) > 0)
1621 {
1622 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1623 if (rc > 0)
1624 {
1625 if (rc > 150) rc = 150;
1626 smtp_inbuffer[rc] = 0;
1627 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1628 "synchronization error (input sent without waiting for greeting): "
1629 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1630 string_printing(smtp_inbuffer));
1631 smtp_printf("554 SMTP synchronization error\r\n");
1632 return FALSE;
1633 }
1634 }
1635 }
1636
1637 /* Now output the banner */
1638
1639 smtp_printf("%s", ss);
1640 return TRUE;
1641 }
1642
1643
1644
1645
1646
1647 /*************************************************
1648 * Handle SMTP syntax and protocol errors *
1649 *************************************************/
1650
1651 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1652 to do so. Then transmit the error response. The return value depends on the
1653 number of syntax and protocol errors in this SMTP session.
1654
1655 Arguments:
1656 type error type, given as a log flag bit
1657 code response code; <= 0 means don't send a response
1658 data data to reflect in the response (can be NULL)
1659 errmess the error message
1660
1661 Returns: -1 limit of syntax/protocol errors NOT exceeded
1662 +1 limit of syntax/protocol errors IS exceeded
1663
1664 These values fit in with the values of the "done" variable in the main
1665 processing loop in smtp_setup_msg(). */
1666
1667 static int
1668 synprot_error(int type, int code, uschar *data, uschar *errmess)
1669 {
1670 int yield = -1;
1671
1672 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1673 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1674 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1675
1676 if (++synprot_error_count > smtp_max_synprot_errors)
1677 {
1678 yield = 1;
1679 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1680 "syntax or protocol errors (last command was \"%s\")",
1681 host_and_ident(FALSE), smtp_cmd_buffer);
1682 }
1683
1684 if (code > 0)
1685 {
1686 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1687 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1688 if (yield == 1)
1689 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1690 }
1691
1692 return yield;
1693 }
1694
1695
1696
1697
1698 /*************************************************
1699 * Log incomplete transactions *
1700 *************************************************/
1701
1702 /* This function is called after a transaction has been aborted by RSET, QUIT,
1703 connection drops or other errors. It logs the envelope information received
1704 so far in order to preserve address verification attempts.
1705
1706 Argument: string to indicate what aborted the transaction
1707 Returns: nothing
1708 */
1709
1710 static void
1711 incomplete_transaction_log(uschar *what)
1712 {
1713 if (sender_address == NULL || /* No transaction in progress */
1714 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1715 ) return;
1716
1717 /* Build list of recipients for logging */
1718
1719 if (recipients_count > 0)
1720 {
1721 int i;
1722 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1723 for (i = 0; i < recipients_count; i++)
1724 raw_recipients[i] = recipients_list[i].address;
1725 raw_recipients_count = recipients_count;
1726 }
1727
1728 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1729 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1730 }
1731
1732
1733
1734
1735 /*************************************************
1736 * Send SMTP response, possibly multiline *
1737 *************************************************/
1738
1739 /* There are, it seems, broken clients out there that cannot handle multiline
1740 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1741 output nothing for non-final calls, and only the first line for anything else.
1742
1743 Arguments:
1744 code SMTP code
1745 final FALSE if the last line isn't the final line
1746 msg message text, possibly containing newlines
1747
1748 Returns: nothing
1749 */
1750
1751 void
1752 smtp_respond(int code, BOOL final, uschar *msg)
1753 {
1754 if (!final && no_multiline_responses) return;
1755
1756 for (;;)
1757 {
1758 uschar *nl = Ustrchr(msg, '\n');
1759 if (nl == NULL)
1760 {
1761 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1762 return;
1763 }
1764 else if (nl[1] == 0 || no_multiline_responses)
1765 {
1766 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1767 return;
1768 }
1769 else
1770 {
1771 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1772 msg = nl + 1;
1773 while (isspace(*msg)) msg++;
1774 }
1775 }
1776 }
1777
1778
1779
1780
1781 /*************************************************
1782 * Handle an ACL failure *
1783 *************************************************/
1784
1785 /* This function is called when acl_check() fails. As well as calls from within
1786 this module, it is called from receive.c for an ACL after DATA. It sorts out
1787 logging the incident, and sets up the error response. A message containing
1788 newlines is turned into a multiline SMTP response, but for logging, only the
1789 first line is used.
1790
1791 There's a table of the response codes to use in globals.c, along with the table
1792 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1793 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1794 that the response should be 252 in the disabled state, because there are broken
1795 clients that try VRFY before RCPT. A 5xx response should be given only when the
1796 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1797 given on refusal, and for AUTH, 503.
1798
1799 Arguments:
1800 where where the ACL was called from
1801 rc the failure code
1802 user_msg a message that can be included in an SMTP response
1803 log_msg a message for logging
1804
1805 Returns: 0 in most cases
1806 2 if the failure code was FAIL_DROP, in which case the
1807 SMTP connection should be dropped (this value fits with the
1808 "done" variable in smtp_setup_msg() below)
1809 */
1810
1811 int
1812 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1813 {
1814 int code = acl_wherecodes[where];
1815 BOOL drop = rc == FAIL_DROP;
1816 uschar *lognl;
1817 uschar *sender_info = US"";
1818 uschar *what =
1819 #ifdef WITH_CONTENT_SCAN
1820 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1821 #endif
1822 (where == ACL_WHERE_PREDATA)? US"DATA" :
1823 (where == ACL_WHERE_DATA)? US"after DATA" :
1824 (smtp_cmd_argument == NULL)?
1825 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
1826 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_argument);
1827
1828 if (drop) rc = FAIL;
1829
1830 /* We used to have sender_address here; however, there was a bug that was not
1831 updating sender_address after a rewrite during a verify. When this bug was
1832 fixed, sender_address at this point became the rewritten address. I'm not sure
1833 this is what should be logged, so I've changed to logging the unrewritten
1834 address to retain backward compatibility. */
1835
1836 #ifndef WITH_CONTENT_SCAN
1837 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1838 #else
1839 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1840 #endif
1841 {
1842 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1843 sender_address_unrewritten : sender_address);
1844 }
1845
1846 /* If there's been a sender verification failure with a specific message, and
1847 we have not sent a response about it yet, do so now, as a preliminary line for
1848 failures, but not defers. However, log it in both cases. */
1849
1850 if (sender_verified_failed != NULL &&
1851 !testflag(sender_verified_failed, af_sverify_told))
1852 {
1853 setflag(sender_verified_failed, af_sverify_told);
1854
1855 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1856 host_and_ident(TRUE),
1857 ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail",
1858 sender_verified_failed->address,
1859 (sender_verified_failed->message == NULL)? US"" :
1860 string_sprintf(": %s", sender_verified_failed->message));
1861
1862 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1863 smtp_respond(code, FALSE, string_sprintf(
1864 testflag(sender_verified_failed, af_verify_pmfail)?
1865 "Postmaster verification failed while checking <%s>\n%s\n"
1866 "Several RFCs state that you are required to have a postmaster\n"
1867 "mailbox for each mail domain. This host does not accept mail\n"
1868 "from domains whose servers reject the postmaster address."
1869 :
1870 testflag(sender_verified_failed, af_verify_nsfail)?
1871 "Callback setup failed while verifying <%s>\n%s\n"
1872 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1873 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1874 "RFC requirements, and stops you from receiving standard bounce\n"
1875 "messages. This host does not accept mail from domains whose servers\n"
1876 "refuse bounces."
1877 :
1878 "Verification failed for <%s>\n%s",
1879 sender_verified_failed->address,
1880 sender_verified_failed->user_message));
1881 }
1882
1883 /* Sort out text for logging */
1884
1885 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1886 lognl = Ustrchr(log_msg, '\n');
1887 if (lognl != NULL) *lognl = 0;
1888
1889 /* Send permanent failure response to the command, but the code used isn't
1890 always a 5xx one - see comments at the start of this function. If the original
1891 rc was FAIL_DROP we drop the connection and yield 2. */
1892
1893 if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1894 US"Administrative prohibition" : user_msg);
1895
1896 /* Send temporary failure response to the command. Don't give any details,
1897 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1898 verb, and for a header verify when smtp_return_error_details is set.
1899
1900 This conditional logic is all somewhat of a mess because of the odd
1901 interactions between temp_details and return_error_details. One day it should
1902 be re-implemented in a tidier fashion. */
1903
1904 else
1905 {
1906 if (acl_temp_details && user_msg != NULL)
1907 {
1908 if (smtp_return_error_details &&
1909 sender_verified_failed != NULL &&
1910 sender_verified_failed->message != NULL)
1911 {
1912 smtp_respond(451, FALSE, sender_verified_failed->message);
1913 }
1914 smtp_respond(451, TRUE, user_msg);
1915 }
1916 else
1917 smtp_printf("451 Temporary local problem - please try later\r\n");
1918 }
1919
1920 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
1921 Otherwise, log why it is closing if required and return 2. */
1922
1923 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1924 host_and_ident(TRUE),
1925 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1926
1927 if (!drop) return 0;
1928
1929 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1930 smtp_get_connection_info());
1931 return 2;
1932 }
1933
1934
1935
1936
1937 /*************************************************
1938 * Verify HELO argument *
1939 *************************************************/
1940
1941 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
1942 matched. It is also called from ACL processing if verify = helo is used and
1943 verification was not previously tried (i.e. helo_try_verify_hosts was not
1944 matched). The result of its processing is to set helo_verified and
1945 helo_verify_failed. These variables should both be FALSE for this function to
1946 be called.
1947
1948 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
1949 for IPv6 ::ffff: literals.
1950
1951 Argument: none
1952 Returns: TRUE if testing was completed;
1953 FALSE on a temporary failure
1954 */
1955
1956 BOOL
1957 smtp_verify_helo(void)
1958 {
1959 BOOL yield = TRUE;
1960
1961 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
1962 sender_helo_name);
1963
1964 if (sender_helo_name == NULL)
1965 {
1966 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
1967 }
1968
1969 else if (sender_helo_name[0] == '[')
1970 {
1971 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
1972 Ustrlen(sender_host_address)) == 0;
1973
1974 #if HAVE_IPV6
1975 if (!helo_verified)
1976 {
1977 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
1978 helo_verified = Ustrncmp(sender_helo_name + 1,
1979 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
1980 }
1981 #endif
1982
1983 HDEBUG(D_receive)
1984 { if (helo_verified) debug_printf("matched host address\n"); }
1985 }
1986
1987 /* Do a reverse lookup if one hasn't already given a positive or negative
1988 response. If that fails, or the name doesn't match, try checking with a forward
1989 lookup. */
1990
1991 else
1992 {
1993 if (sender_host_name == NULL && !host_lookup_failed)
1994 yield = host_name_lookup() != DEFER;
1995
1996 /* If a host name is known, check it and all its aliases. */
1997
1998 if (sender_host_name != NULL)
1999 {
2000 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2001
2002 if (helo_verified)
2003 {
2004 HDEBUG(D_receive) debug_printf("matched host name\n");
2005 }
2006 else
2007 {
2008 uschar **aliases = sender_host_aliases;
2009 while (*aliases != NULL)
2010 {
2011 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2012 if (helo_verified) break;
2013 }
2014 HDEBUG(D_receive)
2015 {
2016 if (helo_verified)
2017 debug_printf("matched alias %s\n", *(--aliases));
2018 }
2019 }
2020 }
2021
2022 /* Final attempt: try a forward lookup of the helo name */
2023
2024 if (!helo_verified)
2025 {
2026 int rc;
2027 host_item h;
2028 h.name = sender_helo_name;
2029 h.address = NULL;
2030 h.mx = MX_NONE;
2031 h.next = NULL;
2032 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2033 sender_helo_name);
2034 rc = host_find_byname(&h, NULL, NULL, TRUE);
2035 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2036 {
2037 host_item *hh = &h;
2038 while (hh != NULL)
2039 {
2040 if (Ustrcmp(hh->address, sender_host_address) == 0)
2041 {
2042 helo_verified = TRUE;
2043 HDEBUG(D_receive)
2044 debug_printf("IP address for %s matches calling address\n",
2045 sender_helo_name);
2046 break;
2047 }
2048 hh = hh->next;
2049 }
2050 }
2051 }
2052 }
2053
2054 if (!helo_verified) helo_verify_failed = FALSE; /* We've tried ... */
2055 return yield;
2056 }
2057
2058
2059
2060
2061 /*************************************************
2062 * Initialize for SMTP incoming message *
2063 *************************************************/
2064
2065 /* This function conducts the initial dialogue at the start of an incoming SMTP
2066 message, and builds a list of recipients. However, if the incoming message
2067 is part of a batch (-bS option) a separate function is called since it would
2068 be messy having tests splattered about all over this function. This function
2069 therefore handles the case where interaction is occurring. The input and output
2070 files are set up in smtp_in and smtp_out.
2071
2072 The global recipients_list is set to point to a vector of recipient_item
2073 blocks, whose number is given by recipients_count. This is extended by the
2074 receive_add_recipient() function. The global variable sender_address is set to
2075 the sender's address. The yield is +1 if a message has been successfully
2076 started, 0 if a QUIT command was encountered or the connection was refused from
2077 the particular host, or -1 if the connection was lost.
2078
2079 Argument: none
2080
2081 Returns: > 0 message successfully started (reached DATA)
2082 = 0 QUIT read or end of file reached or call refused
2083 < 0 lost connection
2084 */
2085
2086 int
2087 smtp_setup_msg(void)
2088 {
2089 int done = 0;
2090 BOOL toomany = FALSE;
2091 BOOL discarded = FALSE;
2092 BOOL last_was_rej_mail = FALSE;
2093 BOOL last_was_rcpt = FALSE;
2094 void *reset_point = store_get(0);
2095
2096 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2097
2098 /* Reset for start of new message. We allow one RSET not to be counted as a
2099 nonmail command, for those MTAs that insist on sending it between every
2100 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2101 TLS between messages (an Exim client may do this if it has messages queued up
2102 for the host). Note: we do NOT reset AUTH at this point. */
2103
2104 smtp_reset(reset_point);
2105 message_ended = END_NOTSTARTED;
2106
2107 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2108 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2109 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2110 #ifdef SUPPORT_TLS
2111 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2112 #endif
2113
2114 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2115
2116 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2117
2118 /* Batched SMTP is handled in a different function. */
2119
2120 if (smtp_batched_input) return smtp_setup_batch_msg();
2121
2122 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2123 value. The values are 2 larger than the required yield of the function. */
2124
2125 while (done <= 0)
2126 {
2127 uschar **argv;
2128 uschar *etrn_command;
2129 uschar *etrn_serialize_key;
2130 uschar *errmess;
2131 uschar *user_msg, *log_msg;
2132 uschar *recipient = NULL;
2133 uschar *hello = NULL;
2134 uschar *set_id = NULL;
2135 uschar *s, *ss;
2136 BOOL was_rej_mail = FALSE;
2137 BOOL was_rcpt = FALSE;
2138 void (*oldsignal)(int);
2139 pid_t pid;
2140 int start, end, sender_domain, recipient_domain;
2141 int ptr, size, rc;
2142 int c, i;
2143 auth_instance *au;
2144
2145 switch(smtp_read_command(TRUE))
2146 {
2147 /* The AUTH command is not permitted to occur inside a transaction, and may
2148 occur successfully only once per connection, and then only when we've
2149 advertised it. Actually, that isn't quite true. When TLS is started, all
2150 previous information about a connection must be discarded, so a new AUTH is
2151 permitted at that time.
2152
2153 AUTH is initially labelled as a "nonmail command" so that one occurrence
2154 doesn't get counted. We change the label here so that multiple failing
2155 AUTHS will eventually hit the nonmail threshold. */
2156
2157 case AUTH_CMD:
2158 authentication_failed = TRUE;
2159 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2160
2161 if (!auth_advertised)
2162 {
2163 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2164 US"AUTH command used when not advertised");
2165 break;
2166 }
2167 if (sender_host_authenticated != NULL)
2168 {
2169 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2170 US"already authenticated");
2171 break;
2172 }
2173 if (sender_address != NULL)
2174 {
2175 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2176 US"not permitted in mail transaction");
2177 break;
2178 }
2179
2180 /* Check the ACL */
2181
2182 if (acl_smtp_auth != NULL)
2183 {
2184 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2185 if (rc != OK)
2186 {
2187 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2188 break;
2189 }
2190 }
2191
2192 /* Find the name of the requested authentication mechanism. */
2193
2194 s = smtp_cmd_argument;
2195 while ((c = *smtp_cmd_argument) != 0 && !isspace(c))
2196 {
2197 if (!isalnum(c) && c != '-' && c != '_')
2198 {
2199 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2200 US"invalid character in authentication mechanism name");
2201 goto COMMAND_LOOP;
2202 }
2203 smtp_cmd_argument++;
2204 }
2205
2206 /* If not at the end of the line, we must be at white space. Terminate the
2207 name and move the pointer on to any data that may be present. */
2208
2209 if (*smtp_cmd_argument != 0)
2210 {
2211 *smtp_cmd_argument++ = 0;
2212 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
2213 }
2214
2215 /* Search for an authentication mechanism which is configured for use
2216 as a server and which has been advertised. */
2217
2218 for (au = auths; au != NULL; au = au->next)
2219 {
2220 if (strcmpic(s, au->public_name) == 0 && au->server &&
2221 au->advertised) break;
2222 }
2223
2224 if (au == NULL)
2225 {
2226 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2227 string_sprintf("%s authentication mechanism not supported", s));
2228 break;
2229 }
2230
2231 /* Run the checking code, passing the remainder of the command line as
2232 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2233 it as the only set numerical variable. The authenticator may set $auth<n>
2234 and also set other numeric variables. The $auth<n> variables are preferred
2235 nowadays; the numerical variables remain for backwards compatibility.
2236
2237 Afterwards, have a go at expanding the set_id string, even if
2238 authentication failed - for bad passwords it can be useful to log the
2239 userid. On success, require set_id to expand and exist, and put it in
2240 authenticated_id. Save this in permanent store, as the working store gets
2241 reset at HELO, RSET, etc. */
2242
2243 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2244 expand_nmax = 0;
2245 expand_nlength[0] = 0; /* $0 contains nothing */
2246
2247 c = (au->info->servercode)(au, smtp_cmd_argument);
2248 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2249 expand_nmax = -1; /* Reset numeric variables */
2250 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2251
2252 /* The value of authenticated_id is stored in the spool file and printed in
2253 log lines. It must not contain binary zeros or newline characters. In
2254 normal use, it never will, but when playing around or testing, this error
2255 can (did) happen. To guard against this, ensure that the id contains only
2256 printing characters. */
2257
2258 if (set_id != NULL) set_id = string_printing(set_id);
2259
2260 /* For the non-OK cases, set up additional logging data if set_id
2261 is not empty. */
2262
2263 if (c != OK)
2264 {
2265 if (set_id != NULL && *set_id != 0)
2266 set_id = string_sprintf(" (set_id=%s)", set_id);
2267 else set_id = US"";
2268 }
2269
2270 /* Switch on the result */
2271
2272 switch(c)
2273 {
2274 case OK:
2275 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2276 {
2277 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2278 sender_host_authenticated = au->name;
2279 authentication_failed = FALSE;
2280 received_protocol =
2281 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2282 ((sender_host_address != NULL)? pnlocal : 0);
2283 s = ss = US"235 Authentication succeeded";
2284 authenticated_by = au;
2285 break;
2286 }
2287
2288 /* Authentication succeeded, but we failed to expand the set_id string.
2289 Treat this as a temporary error. */
2290
2291 auth_defer_msg = expand_string_message;
2292 /* Fall through */
2293
2294 case DEFER:
2295 s = string_sprintf("435 Unable to authenticate at present%s",
2296 auth_defer_user_msg);
2297 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2298 set_id, auth_defer_msg);
2299 break;
2300
2301 case BAD64:
2302 s = ss = US"501 Invalid base64 data";
2303 break;
2304
2305 case CANCELLED:
2306 s = ss = US"501 Authentication cancelled";
2307 break;
2308
2309 case UNEXPECTED:
2310 s = ss = US"553 Initial data not expected";
2311 break;
2312
2313 case FAIL:
2314 s = US"535 Incorrect authentication data";
2315 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2316 break;
2317
2318 default:
2319 s = US"435 Internal error";
2320 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2321 "check", set_id, c);
2322 break;
2323 }
2324
2325 smtp_printf("%s\r\n", s);
2326 if (c != OK)
2327 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2328 au->name, host_and_ident(FALSE), ss);
2329
2330 break; /* AUTH_CMD */
2331
2332 /* The HELO/EHLO commands are permitted to appear in the middle of a
2333 session as well as at the beginning. They have the effect of a reset in
2334 addition to their other functions. Their absence at the start cannot be
2335 taken to be an error.
2336
2337 RFC 2821 says:
2338
2339 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2340 or 502 failure replies MUST be returned as appropriate. The SMTP
2341 server MUST stay in the same state after transmitting these replies
2342 that it was in before the EHLO was received.
2343
2344 Therefore, we do not do the reset until after checking the command for
2345 acceptability. This change was made for Exim release 4.11. Previously
2346 it did the reset first. */
2347
2348 case HELO_CMD:
2349 hello = US"HELO";
2350 esmtp = FALSE;
2351 goto HELO_EHLO;
2352
2353 case EHLO_CMD:
2354 hello = US"EHLO";
2355 esmtp = TRUE;
2356
2357 HELO_EHLO: /* Common code for HELO and EHLO */
2358 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2359 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2360
2361 /* Reject the HELO if its argument was invalid or non-existent. A
2362 successful check causes the argument to be saved in malloc store. */
2363
2364 if (!check_helo(smtp_cmd_argument))
2365 {
2366 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2367
2368 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2369 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2370 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2371 string_printing(smtp_cmd_argument));
2372
2373 if (++synprot_error_count > smtp_max_synprot_errors)
2374 {
2375 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2376 "syntax or protocol errors (last command was \"%s\")",
2377 host_and_ident(FALSE), smtp_cmd_buffer);
2378 done = 1;
2379 }
2380
2381 break;
2382 }
2383
2384 /* If sender_host_unknown is true, we have got here via the -bs interface,
2385 not called from inetd. Otherwise, we are running an IP connection and the
2386 host address will be set. If the helo name is the primary name of this
2387 host and we haven't done a reverse lookup, force one now. If helo_required
2388 is set, ensure that the HELO name matches the actual host. If helo_verify
2389 is set, do the same check, but softly. */
2390
2391 if (!sender_host_unknown)
2392 {
2393 BOOL old_helo_verified = helo_verified;
2394 uschar *p = smtp_cmd_argument;
2395
2396 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2397 *p = 0;
2398
2399 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2400 because otherwise the log can be confusing. */
2401
2402 if (sender_host_name == NULL &&
2403 (deliver_domain = sender_helo_name, /* set $domain */
2404 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2405 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2406 (void)host_name_lookup();
2407
2408 /* Rebuild the fullhost info to include the HELO name (and the real name
2409 if it was looked up.) */
2410
2411 host_build_sender_fullhost(); /* Rebuild */
2412 set_process_info("handling%s incoming connection from %s",
2413 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2414
2415 /* Verify if configured. This doesn't give much security, but it does
2416 make some people happy to be able to do it. If helo_required is set,
2417 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2418 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2419 now obsolescent, since the verification can now be requested selectively
2420 at ACL time. */
2421
2422 helo_verified = helo_verify_failed = FALSE;
2423 if (helo_required || helo_verify)
2424 {
2425 BOOL tempfail = !smtp_verify_helo();
2426 if (!helo_verified)
2427 {
2428 if (helo_required)
2429 {
2430 smtp_printf("%d %s argument does not match calling host\r\n",
2431 tempfail? 451 : 550, hello);
2432 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2433 tempfail? "temporarily " : "",
2434 hello, sender_helo_name, host_and_ident(FALSE));
2435 helo_verified = old_helo_verified;
2436 break; /* End of HELO/EHLO processing */
2437 }
2438 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2439 "helo_try_verify_hosts\n", hello);
2440 }
2441 }
2442 }
2443
2444 #ifdef EXPERIMENTAL_SPF
2445 /* set up SPF context */
2446 spf_init(sender_helo_name, sender_host_address);
2447 #endif
2448
2449 /* Apply an ACL check if one is defined */
2450
2451 if (acl_smtp_helo != NULL)
2452 {
2453 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2454 if (rc != OK)
2455 {
2456 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2457 sender_helo_name = NULL;
2458 host_build_sender_fullhost(); /* Rebuild */
2459 break;
2460 }
2461 }
2462
2463 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2464 abandoning any previous message. */
2465
2466 received_protocol = (esmtp?
2467 protocols[pextend +
2468 ((sender_host_authenticated != NULL)? pauthed : 0) +
2469 ((tls_active >= 0)? pcrpted : 0)]
2470 :
2471 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2472 +
2473 ((sender_host_address != NULL)? pnlocal : 0);
2474
2475 smtp_reset(reset_point);
2476 toomany = FALSE;
2477
2478 /* Generate an OK reply, including the ident if present, and also
2479 the IP address if present. Reflecting back the ident is intended
2480 as a deterrent to mail forgers. For maximum efficiency, and also
2481 because some broken systems expect each response to be in a single
2482 packet, arrange that it is sent in one write(). */
2483
2484 auth_advertised = FALSE;
2485 pipelining_advertised = FALSE;
2486 #ifdef SUPPORT_TLS
2487 tls_advertised = FALSE;
2488 #endif
2489
2490 s = string_sprintf("250 %s Hello %s%s%s",
2491 smtp_active_hostname,
2492 (sender_ident == NULL)? US"" : sender_ident,
2493 (sender_ident == NULL)? US"" : US" at ",
2494 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2495
2496 ptr = Ustrlen(s);
2497 size = ptr + 1;
2498
2499 if (sender_host_address != NULL)
2500 {
2501 s = string_cat(s, &size, &ptr, US" [", 2);
2502 s = string_cat(s, &size, &ptr, sender_host_address,
2503 Ustrlen(sender_host_address));
2504 s = string_cat(s, &size, &ptr, US"]", 1);
2505 }
2506
2507 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2508
2509 /* If we received EHLO, we must create a multiline response which includes
2510 the functions supported. */
2511
2512 if (esmtp)
2513 {
2514 s[3] = '-';
2515
2516 /* I'm not entirely happy with this, as an MTA is supposed to check
2517 that it has enough room to accept a message of maximum size before
2518 it sends this. However, there seems little point in not sending it.
2519 The actual size check happens later at MAIL FROM time. By postponing it
2520 till then, VRFY and EXPN can be used after EHLO when space is short. */
2521
2522 if (thismessage_size_limit > 0)
2523 {
2524 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2525 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2526 }
2527 else
2528 {
2529 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2530 }
2531
2532 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2533 clean; if it has an 8-bit character in its hand, it just sends it. It
2534 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2535 However, some users want this option simply in order to stop MUAs
2536 mangling messages that contain top-bit-set characters. It is therefore
2537 provided as an option. */
2538
2539 if (accept_8bitmime)
2540 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2541
2542 /* Advertise ETRN if there's an ACL checking whether a host is
2543 permitted to issue it; a check is made when any host actually tries. */
2544
2545 if (acl_smtp_etrn != NULL)
2546 {
2547 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2548 }
2549
2550 /* Advertise EXPN if there's an ACL checking whether a host is
2551 permitted to issue it; a check is made when any host actually tries. */
2552
2553 if (acl_smtp_expn != NULL)
2554 {
2555 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2556 }
2557
2558 /* Exim is quite happy with pipelining, so let the other end know that
2559 it is safe to use it, unless advertising is disabled. */
2560
2561 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2562 {
2563 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2564 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2565 pipelining_advertised = TRUE;
2566 }
2567
2568 /* If any server authentication mechanisms are configured, advertise
2569 them if the current host is in auth_advertise_hosts. The problem with
2570 advertising always is that some clients then require users to
2571 authenticate (and aren't configurable otherwise) even though it may not
2572 be necessary (e.g. if the host is in host_accept_relay).
2573
2574 RFC 2222 states that SASL mechanism names contain only upper case
2575 letters, so output the names in upper case, though we actually recognize
2576 them in either case in the AUTH command. */
2577
2578 if (auths != NULL)
2579 {
2580 if (verify_check_host(&auth_advertise_hosts) == OK)
2581 {
2582 auth_instance *au;
2583 BOOL first = TRUE;
2584 for (au = auths; au != NULL; au = au->next)
2585 {
2586 if (au->server && (au->advertise_condition == NULL ||
2587 expand_check_condition(au->advertise_condition, au->name,
2588 US"authenticator")))
2589 {
2590 int saveptr;
2591 if (first)
2592 {
2593 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2594 first = FALSE;
2595 auth_advertised = TRUE;
2596 }
2597 saveptr = ptr;
2598 s = string_cat(s, &size, &ptr, US" ", 1);
2599 s = string_cat(s, &size, &ptr, au->public_name,
2600 Ustrlen(au->public_name));
2601 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2602 au->advertised = TRUE;
2603 }
2604 else au->advertised = FALSE;
2605 }
2606 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2607 }
2608 }
2609
2610 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2611 if it has been included in the binary, and the host matches
2612 tls_advertise_hosts. We must *not* advertise if we are already in a
2613 secure connection. */
2614
2615 #ifdef SUPPORT_TLS
2616 if (tls_active < 0 &&
2617 verify_check_host(&tls_advertise_hosts) != FAIL)
2618 {
2619 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2620 tls_advertised = TRUE;
2621 }
2622 #endif
2623
2624 /* Finish off the multiline reply with one that is always available. */
2625
2626 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2627 }
2628
2629 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2630 has been seen. */
2631
2632 s[ptr] = 0;
2633
2634 #ifdef SUPPORT_TLS
2635 if (tls_active >= 0) (void)tls_write(s, ptr); else
2636 #endif
2637
2638 (void)fwrite(s, 1, ptr, smtp_out);
2639 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2640 helo_seen = TRUE;
2641 break; /* HELO/EHLO */
2642
2643
2644 /* The MAIL command requires an address as an operand. All we do
2645 here is to parse it for syntactic correctness. The form "<>" is
2646 a special case which converts into an empty string. The start/end
2647 pointers in the original are not used further for this address, as
2648 it is the canonical extracted address which is all that is kept. */
2649
2650 case MAIL_CMD:
2651 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2652 was_rej_mail = TRUE; /* Reset if accepted */
2653
2654 if (helo_required && !helo_seen)
2655 {
2656 smtp_printf("503 HELO or EHLO required\r\n");
2657 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2658 "HELO/EHLO given", host_and_ident(FALSE));
2659 break;
2660 }
2661
2662 if (sender_address != NULL)
2663 {
2664 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2665 US"sender already given");
2666 break;
2667 }
2668
2669 if (smtp_cmd_argument[0] == 0)
2670 {
2671 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2672 US"MAIL must have an address operand");
2673 break;
2674 }
2675
2676 /* Check to see if the limit for messages per connection would be
2677 exceeded by accepting further messages. */
2678
2679 if (smtp_accept_max_per_connection > 0 &&
2680 smtp_mailcmd_count > smtp_accept_max_per_connection)
2681 {
2682 smtp_printf("421 too many messages in this connection\r\n");
2683 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2684 "messages in one connection", host_and_ident(TRUE));
2685 break;
2686 }
2687
2688 /* Reset for start of message - even if this is going to fail, we
2689 obviously need to throw away any previous data. */
2690
2691 smtp_reset(reset_point);
2692 toomany = FALSE;
2693 sender_data = recipient_data = NULL;
2694
2695 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2696
2697 if (esmtp) for(;;)
2698 {
2699 uschar *name, *value, *end;
2700 unsigned long int size;
2701
2702 if (!extract_option(&name, &value)) break;
2703
2704 /* Handle SIZE= by reading the value. We don't do the check till later,
2705 in order to be able to log the sender address on failure. */
2706
2707 if (strcmpic(name, US"SIZE") == 0 &&
2708 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2709 {
2710 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2711 size = INT_MAX;
2712 message_size = (int)size;
2713 }
2714
2715 /* If this session was initiated with EHLO and accept_8bitmime is set,
2716 Exim will have indicated that it supports the BODY=8BITMIME option. In
2717 fact, it does not support this according to the RFCs, in that it does not
2718 take any special action for forwarding messages containing 8-bit
2719 characters. That is why accept_8bitmime is not the default setting, but
2720 some sites want the action that is provided. We recognize both "8BITMIME"
2721 and "7BIT" as body types, but take no action. */
2722
2723 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2724 (strcmpic(value, US"8BITMIME") == 0 ||
2725 strcmpic(value, US"7BIT") == 0)) {}
2726
2727 /* Handle the AUTH extension. If the value given is not "<>" and either
2728 the ACL says "yes" or there is no ACL but the sending host is
2729 authenticated, we set it up as the authenticated sender. However, if the
2730 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2731 the condition is met. The value of AUTH is an xtext, which means that +,
2732 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2733 coding. */
2734
2735 else if (strcmpic(name, US"AUTH") == 0)
2736 {
2737 if (Ustrcmp(value, "<>") != 0)
2738 {
2739 int rc;
2740 uschar *ignore_msg;
2741
2742 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2743 {
2744 /* Put back terminator overrides for error message */
2745 name[-1] = ' ';
2746 value[-1] = '=';
2747 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2748 US"invalid data for AUTH");
2749 goto COMMAND_LOOP;
2750 }
2751
2752 if (acl_smtp_mailauth == NULL)
2753 {
2754 ignore_msg = US"client not authenticated";
2755 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2756 }
2757 else
2758 {
2759 ignore_msg = US"rejected by ACL";
2760 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2761 &user_msg, &log_msg);
2762 }
2763
2764 switch (rc)
2765 {
2766 case OK:
2767 if (authenticated_by == NULL ||
2768 authenticated_by->mail_auth_condition == NULL ||
2769 expand_check_condition(authenticated_by->mail_auth_condition,
2770 authenticated_by->name, US"authenticator"))
2771 break; /* Accept the AUTH */
2772
2773 ignore_msg = US"server_mail_auth_condition failed";
2774 if (authenticated_id != NULL)
2775 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2776 ignore_msg, authenticated_id);
2777
2778 /* Fall through */
2779
2780 case FAIL:
2781 authenticated_sender = NULL;
2782 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2783 value, host_and_ident(TRUE), ignore_msg);
2784 break;
2785
2786 /* Should only get DEFER or ERROR here. Put back terminator
2787 overrides for error message */
2788
2789 default:
2790 name[-1] = ' ';
2791 value[-1] = '=';
2792 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2793 log_msg);
2794 goto COMMAND_LOOP;
2795 }
2796 }
2797 }
2798
2799 /* Unknown option. Stick back the terminator characters and break
2800 the loop. An error for a malformed address will occur. */
2801
2802 else
2803 {
2804 name[-1] = ' ';
2805 value[-1] = '=';
2806 break;
2807 }
2808 }
2809
2810 /* If we have passed the threshold for rate limiting, apply the current
2811 delay, and update it for next time, provided this is a limited host. */
2812
2813 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2814 verify_check_host(&smtp_ratelimit_hosts) == OK)
2815 {
2816 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2817 smtp_delay_mail/1000.0);
2818 millisleep((int)smtp_delay_mail);
2819 smtp_delay_mail *= smtp_rlm_factor;
2820 if (smtp_delay_mail > (double)smtp_rlm_limit)
2821 smtp_delay_mail = (double)smtp_rlm_limit;
2822 }
2823
2824 /* Now extract the address, first applying any SMTP-time rewriting. The
2825 TRUE flag allows "<>" as a sender address. */
2826
2827 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2828 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
2829 global_rewrite_rules) : smtp_cmd_argument;
2830
2831 /* rfc821_domains = TRUE; << no longer needed */
2832 raw_sender =
2833 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2834 TRUE);
2835 /* rfc821_domains = FALSE; << no longer needed */
2836
2837 if (raw_sender == NULL)
2838 {
2839 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
2840 break;
2841 }
2842
2843 sender_address = raw_sender;
2844
2845 /* If there is a configured size limit for mail, check that this message
2846 doesn't exceed it. The check is postponed to this point so that the sender
2847 can be logged. */
2848
2849 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2850 {
2851 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2852 log_write(L_size_reject,
2853 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2854 "message too big: size%s=%d max=%d",
2855 sender_address,
2856 host_and_ident(TRUE),
2857 (message_size == INT_MAX)? ">" : "",
2858 message_size,
2859 thismessage_size_limit);
2860 sender_address = NULL;
2861 break;
2862 }
2863
2864 /* Check there is enough space on the disk unless configured not to.
2865 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2866 plus the current message - i.e. we accept the message only if it won't
2867 reduce the space below the threshold. Add 5000 to the size to allow for
2868 overheads such as the Received: line and storing of recipients, etc.
2869 By putting the check here, even when SIZE is not given, it allow VRFY
2870 and EXPN etc. to be used when space is short. */
2871
2872 if (!receive_check_fs(
2873 (smtp_check_spool_space && message_size >= 0)?
2874 message_size + 5000 : 0))
2875 {
2876 smtp_printf("452 Space shortage, please try later\r\n");
2877 sender_address = NULL;
2878 break;
2879 }
2880
2881 /* If sender_address is unqualified, reject it, unless this is a locally
2882 generated message, or the sending host or net is permitted to send
2883 unqualified addresses - typically local machines behaving as MUAs -
2884 in which case just qualify the address. The flag is set above at the start
2885 of the SMTP connection. */
2886
2887 if (sender_domain == 0 && sender_address[0] != 0)
2888 {
2889 if (allow_unqualified_sender)
2890 {
2891 sender_domain = Ustrlen(sender_address) + 1;
2892 sender_address = rewrite_address_qualify(sender_address, FALSE);
2893 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2894 raw_sender);
2895 }
2896 else
2897 {
2898 smtp_printf("501 %s: sender address must contain a domain\r\n",
2899 smtp_cmd_argument);
2900 log_write(L_smtp_syntax_error,
2901 LOG_MAIN|LOG_REJECT,
2902 "unqualified sender rejected: <%s> %s%s",
2903 raw_sender,
2904 host_and_ident(TRUE),
2905 host_lookup_msg);
2906 sender_address = NULL;
2907 break;
2908 }
2909 }
2910
2911 /* Apply an ACL check if one is defined, before responding */
2912
2913 rc = (acl_smtp_mail == NULL)? OK :
2914 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2915
2916 if (rc == OK || rc == DISCARD)
2917 {
2918 smtp_printf("250 OK\r\n");
2919 smtp_delay_rcpt = smtp_rlr_base;
2920 recipients_discarded = (rc == DISCARD);
2921 was_rej_mail = FALSE;
2922 }
2923
2924 else
2925 {
2926 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2927 sender_address = NULL;
2928 }
2929 break;
2930
2931
2932 /* The RCPT command requires an address as an operand. All we do
2933 here is to parse it for syntactic correctness. There may be any number
2934 of RCPT commands, specifying multiple senders. We build them all into
2935 a data structure that is in argc/argv format. The start/end values
2936 given by parse_extract_address are not used, as we keep only the
2937 extracted address. */
2938
2939 case RCPT_CMD:
2940 rcpt_count++;
2941 was_rcpt = TRUE;
2942
2943 /* There must be a sender address; if the sender was rejected and
2944 pipelining was advertised, we assume the client was pipelining, and do not
2945 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2946 get the same treatment. */
2947
2948 if (sender_address == NULL)
2949 {
2950 if (pipelining_advertised && last_was_rej_mail)
2951 {
2952 smtp_printf("503 sender not yet given\r\n");
2953 was_rej_mail = TRUE;
2954 }
2955 else
2956 {
2957 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2958 US"sender not yet given");
2959 was_rcpt = FALSE; /* Not a valid RCPT */
2960 }
2961 rcpt_fail_count++;
2962 break;
2963 }
2964
2965 /* Check for an operand */
2966
2967 if (smtp_cmd_argument[0] == 0)
2968 {
2969 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2970 US"RCPT must have an address operand");
2971 rcpt_fail_count++;
2972 break;
2973 }
2974
2975 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2976 as a recipient address */
2977
2978 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2979 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
2980 global_rewrite_rules) : smtp_cmd_argument;
2981
2982 /* rfc821_domains = TRUE; << no longer needed */
2983 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2984 &recipient_domain, FALSE);
2985 /* rfc821_domains = FALSE; << no longer needed */
2986
2987 if (recipient == NULL)
2988 {
2989 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
2990 rcpt_fail_count++;
2991 break;
2992 }
2993
2994 /* If the recipient address is unqualified, reject it, unless this is a
2995 locally generated message. However, unqualified addresses are permitted
2996 from a configured list of hosts and nets - typically when behaving as
2997 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2998 really. The flag is set at the start of the SMTP connection.
2999
3000 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3001 assumed this meant "reserved local part", but the revision of RFC 821 and
3002 friends now makes it absolutely clear that it means *mailbox*. Consequently
3003 we must always qualify this address, regardless. */
3004
3005 if (recipient_domain == 0)
3006 {
3007 if (allow_unqualified_recipient ||
3008 strcmpic(recipient, US"postmaster") == 0)
3009 {
3010 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3011 recipient);
3012 recipient_domain = Ustrlen(recipient) + 1;
3013 recipient = rewrite_address_qualify(recipient, TRUE);
3014 }
3015 else
3016 {
3017 rcpt_fail_count++;
3018 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3019 smtp_cmd_argument);
3020 log_write(L_smtp_syntax_error,
3021 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3022 "<%s> %s%s", recipient, host_and_ident(TRUE),
3023 host_lookup_msg);
3024 break;
3025 }
3026 }
3027
3028 /* Check maximum allowed */
3029
3030 if (rcpt_count > recipients_max && recipients_max > 0)
3031 {
3032 if (recipients_max_reject)
3033 {
3034 rcpt_fail_count++;
3035 smtp_printf("552 too many recipients\r\n");
3036 if (!toomany)
3037 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3038 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3039 }
3040 else
3041 {
3042 rcpt_defer_count++;
3043 smtp_printf("452 too many recipients\r\n");
3044 if (!toomany)
3045 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3046 "temporarily rejected: sender=<%s> %s", sender_address,
3047 host_and_ident(TRUE));
3048 }
3049
3050 toomany = TRUE;
3051 break;
3052 }
3053
3054 /* If we have passed the threshold for rate limiting, apply the current
3055 delay, and update it for next time, provided this is a limited host. */
3056
3057 if (rcpt_count > smtp_rlr_threshold &&
3058 verify_check_host(&smtp_ratelimit_hosts) == OK)
3059 {
3060 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3061 smtp_delay_rcpt/1000.0);
3062 millisleep((int)smtp_delay_rcpt);
3063 smtp_delay_rcpt *= smtp_rlr_factor;
3064 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3065 smtp_delay_rcpt = (double)smtp_rlr_limit;
3066 }
3067
3068 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3069 for them. Otherwise, check the access control list for this recipient. */
3070
3071 rc = recipients_discarded? DISCARD :
3072 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3073
3074 /* The ACL was happy */
3075
3076 if (rc == OK)
3077 {
3078 smtp_printf("250 Accepted\r\n");
3079 receive_add_recipient(recipient, -1);
3080 }
3081
3082 /* The recipient was discarded */
3083
3084 else if (rc == DISCARD)
3085 {
3086 smtp_printf("250 Accepted\r\n");
3087 rcpt_fail_count++;
3088 discarded = TRUE;
3089 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3090 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3091 (sender_address_unrewritten != NULL)?
3092 sender_address_unrewritten : sender_address,
3093 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3094 (log_msg == NULL)? US"" : US": ",
3095 (log_msg == NULL)? US"" : log_msg);
3096 }
3097
3098 /* Either the ACL failed the address, or it was deferred. */
3099
3100 else
3101 {
3102 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3103 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3104 }
3105 break;
3106
3107
3108 /* The DATA command is legal only if it follows successful MAIL FROM
3109 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3110 not counted as a protocol error if it follows RCPT (which must have been
3111 rejected if there are no recipients.) This function is complete when a
3112 valid DATA command is encountered.
3113
3114 Note concerning the code used: RFC 2821 says this:
3115
3116 - If there was no MAIL, or no RCPT, command, or all such commands
3117 were rejected, the server MAY return a "command out of sequence"
3118 (503) or "no valid recipients" (554) reply in response to the
3119 DATA command.
3120
3121 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3122 because it is the same whether pipelining is in use or not. */
3123
3124 case DATA_CMD:
3125 if (!discarded && recipients_count <= 0)
3126 {
3127 if (pipelining_advertised && last_was_rcpt)
3128 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3129 else
3130 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3131 US"valid RCPT command must precede DATA");
3132 break;
3133 }
3134
3135 if (toomany && recipients_max_reject)
3136 {
3137 sender_address = NULL; /* This will allow a new MAIL without RSET */
3138 sender_address_unrewritten = NULL;
3139 smtp_printf("554 Too many recipients\r\n");
3140 break;
3141 }
3142
3143 if (acl_smtp_predata == NULL) rc = OK; else
3144 {
3145 enable_dollar_recipients = TRUE;
3146 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3147 &log_msg);
3148 enable_dollar_recipients = FALSE;
3149 }
3150
3151 if (rc == OK)
3152 {
3153 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3154 done = 3;
3155 message_ended = END_NOTENDED; /* Indicate in middle of data */
3156 }
3157
3158 /* Either the ACL failed the address, or it was deferred. */
3159
3160 else
3161 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3162
3163 break;
3164
3165
3166 case VRFY_CMD:
3167 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3168 if (rc != OK)
3169 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3170 else
3171 {
3172 uschar *address;
3173 uschar *s = NULL;
3174
3175 /* rfc821_domains = TRUE; << no longer needed */
3176 address = parse_extract_address(smtp_cmd_argument, &errmess, &start, &end,
3177 &recipient_domain, FALSE);
3178 /* rfc821_domains = FALSE; << no longer needed */
3179
3180 if (address == NULL)
3181 s = string_sprintf("501 %s", errmess);
3182 else
3183 {
3184 address_item *addr = deliver_make_addr(address, FALSE);
3185 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3186 -1, -1, NULL, NULL, NULL))
3187 {
3188 case OK:
3189 s = string_sprintf("250 <%s> is deliverable", address);
3190 break;
3191
3192 case DEFER:
3193 s = (addr->message != NULL)?
3194 string_sprintf("451 <%s> %s", address, addr->message) :
3195 string_sprintf("451 Cannot resolve <%s> at this time", address);
3196 break;
3197
3198 case FAIL:
3199 s = (addr->message != NULL)?
3200 string_sprintf("550 <%s> %s", address, addr->message) :
3201 string_sprintf("550 <%s> is not deliverable", address);
3202 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3203 smtp_cmd_argument, host_and_ident(TRUE));
3204 break;
3205 }
3206 }
3207
3208 smtp_printf("%s\r\n", s);
3209 }
3210 break;
3211
3212
3213 case EXPN_CMD:
3214 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3215 if (rc != OK)
3216 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3217 else
3218 {
3219 BOOL save_log_testing_mode = log_testing_mode;
3220 address_test_mode = log_testing_mode = TRUE;
3221 (void) verify_address(deliver_make_addr(smtp_cmd_argument, FALSE),
3222 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3223 NULL, NULL, NULL);
3224 address_test_mode = FALSE;
3225 log_testing_mode = save_log_testing_mode; /* true for -bh */
3226 }
3227 break;
3228
3229
3230 #ifdef SUPPORT_TLS
3231
3232 case STARTTLS_CMD:
3233 if (!tls_advertised)
3234 {
3235 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3236 US"STARTTLS command used when not advertised");
3237 break;
3238 }
3239
3240 /* Apply an ACL check if one is defined */
3241
3242 if (acl_smtp_starttls != NULL)
3243 {
3244 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3245 &log_msg);
3246 if (rc != OK)
3247 {
3248 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3249 break;
3250 }
3251 }
3252
3253 /* RFC 2487 is not clear on when this command may be sent, though it
3254 does state that all information previously obtained from the client
3255 must be discarded if a TLS session is started. It seems reasonble to
3256 do an implied RSET when STARTTLS is received. */
3257
3258 incomplete_transaction_log(US"STARTTLS");
3259 smtp_reset(reset_point);
3260 toomany = FALSE;
3261 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3262
3263 /* Attempt to start up a TLS session, and if successful, discard all
3264 knowledge that was obtained previously. At least, that's what the RFC says,
3265 and that's what happens by default. However, in order to work round YAEB,
3266 there is an option to remember the esmtp state. Sigh.
3267
3268 We must allow for an extra EHLO command and an extra AUTH command after
3269 STARTTLS that don't add to the nonmail command count. */
3270
3271 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3272 {
3273 if (!tls_remember_esmtp)
3274 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3275 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3276 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3277 if (sender_helo_name != NULL)
3278 {
3279 store_free(sender_helo_name);
3280 sender_helo_name = NULL;
3281 host_build_sender_fullhost(); /* Rebuild */
3282 set_process_info("handling incoming TLS connection from %s",
3283 host_and_ident(FALSE));
3284 }
3285 received_protocol = (esmtp?
3286 protocols[pextend + pcrpted +
3287 ((sender_host_authenticated != NULL)? pauthed : 0)]
3288 :
3289 protocols[pnormal + pcrpted])
3290 +
3291 ((sender_host_address != NULL)? pnlocal : 0);
3292
3293 sender_host_authenticated = NULL;
3294 authenticated_id = NULL;
3295 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3296 DEBUG(D_tls) debug_printf("TLS active\n");
3297 break; /* Successful STARTTLS */
3298 }
3299
3300 /* Some local configuration problem was discovered before actually trying
3301 to do a TLS handshake; give a temporary error. */
3302
3303 else if (rc == DEFER)
3304 {
3305 smtp_printf("454 TLS currently unavailable\r\n");
3306 break;
3307 }
3308
3309 /* Hard failure. Reject everything except QUIT or closed connection. One
3310 cause for failure is a nested STARTTLS, in which case tls_active remains
3311 set, but we must still reject all incoming commands. */
3312
3313 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3314 while (done <= 0)
3315 {
3316 switch(smtp_read_command(FALSE))
3317 {
3318 case EOF_CMD:
3319 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3320 smtp_get_connection_info());
3321 done = 2;
3322 break;
3323
3324 case QUIT_CMD:
3325 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3326 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3327 smtp_get_connection_info());
3328 done = 2;
3329 break;
3330
3331 default:
3332 smtp_printf("554 Security failure\r\n");
3333 break;
3334 }
3335 }
3336 tls_close(TRUE);
3337 break;
3338 #endif
3339
3340
3341 /* The ACL for QUIT is provided for gathering statistical information or
3342 similar; it does not affect the response code, but it can supply a custom
3343 message. */
3344
3345 case QUIT_CMD:
3346 incomplete_transaction_log(US"QUIT");
3347
3348 if (acl_smtp_quit != NULL)
3349 {
3350 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit,&user_msg,&log_msg);
3351 if (rc == ERROR)
3352 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3353 log_msg);
3354 }
3355 else user_msg = NULL;
3356
3357 if (user_msg == NULL)
3358 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3359 else
3360 smtp_printf("221 %s\r\n", user_msg);
3361
3362 #ifdef SUPPORT_TLS
3363 tls_close(TRUE);
3364 #endif
3365
3366 done = 2;
3367 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3368 smtp_get_connection_info());
3369 break;
3370
3371
3372 case RSET_CMD:
3373 incomplete_transaction_log(US"RSET");
3374 smtp_reset(reset_point);
3375 toomany = FALSE;
3376 smtp_printf("250 Reset OK\r\n");
3377 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3378 break;
3379
3380
3381 case NOOP_CMD:
3382 smtp_printf("250 OK\r\n");
3383 break;
3384
3385
3386 /* Show ETRN/EXPN/VRFY if there's
3387 an ACL for checking hosts; if actually used, a check will be done for
3388 permitted hosts. */
3389
3390 case HELP_CMD:
3391 smtp_printf("214-Commands supported:\r\n");
3392 {
3393 uschar buffer[256];
3394 buffer[0] = 0;
3395 Ustrcat(buffer, " AUTH");
3396 #ifdef SUPPORT_TLS
3397 Ustrcat(buffer, " STARTTLS");
3398 #endif
3399 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3400 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3401 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3402 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3403 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3404 smtp_printf("214%s\r\n", buffer);
3405 }
3406 break;
3407
3408
3409 case EOF_CMD:
3410 incomplete_transaction_log(US"connection lost");
3411 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3412
3413 /* Don't log by default unless in the middle of a message, as some mailers
3414 just drop the call rather than sending QUIT, and it clutters up the logs.
3415 */
3416
3417 if (sender_address != NULL || recipients_count > 0)
3418 log_write(L_lost_incoming_connection,
3419 LOG_MAIN,
3420 "unexpected %s while reading SMTP command from %s%s",
3421 sender_host_unknown? "EOF" : "disconnection",
3422 host_and_ident(FALSE), smtp_read_error);
3423
3424 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3425 smtp_get_connection_info(), smtp_read_error);
3426
3427 done = 1;
3428 break;
3429
3430
3431 case ETRN_CMD:
3432 if (sender_address != NULL)
3433 {
3434 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3435 US"ETRN is not permitted inside a transaction");
3436 break;
3437 }
3438
3439 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
3440 host_and_ident(FALSE));
3441
3442 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
3443 if (rc != OK)
3444 {
3445 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3446 break;
3447 }
3448
3449 /* Compute the serialization key for this command. */
3450
3451 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_argument);
3452
3453 /* If a command has been specified for running as a result of ETRN, we
3454 permit any argument to ETRN. If not, only the # standard form is permitted,
3455 since that is strictly the only kind of ETRN that can be implemented
3456 according to the RFC. */
3457
3458 if (smtp_etrn_command != NULL)
3459 {
3460 uschar *error;
3461 BOOL rc;
3462 etrn_command = smtp_etrn_command;
3463 deliver_domain = smtp_cmd_argument;
3464 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3465 US"ETRN processing", &error);
3466 deliver_domain = NULL;
3467 if (!rc)
3468 {
3469 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3470 error);
3471 smtp_printf("458 Internal failure\r\n");
3472 break;
3473 }
3474 }
3475
3476 /* Else set up to call Exim with the -R option. */
3477
3478 else
3479 {
3480 if (*smtp_cmd_argument++ != '#')
3481 {
3482 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3483 US"argument must begin with #");
3484 break;
3485 }
3486 etrn_command = US"exim -R";
3487 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3488 smtp_cmd_argument);
3489 }
3490
3491 /* If we are host-testing, don't actually do anything. */
3492
3493 if (host_checking)
3494 {
3495 HDEBUG(D_any)
3496 {
3497 debug_printf("ETRN command is: %s\n", etrn_command);
3498 debug_printf("ETRN command execution skipped\n");
3499 }
3500 smtp_printf("250 OK\r\n");
3501 break;
3502 }
3503
3504
3505 /* If ETRN queue runs are to be serialized, check the database to
3506 ensure one isn't already running. */
3507
3508 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3509 {
3510 smtp_printf("458