5c953375c72522fdf8fceb1cc4628e5e217d996f
[exim.git] / src / src / smtp_in.c
1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.27 2005/12/12 15:58:53 ph10 Exp $ */
2
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
6
7 /* Copyright (c) University of Cambridge 1995 - 2005 */
8 /* See the file NOTICE for conditions of use and distribution. */
9
10 /* Functions for handling an incoming SMTP call. */
11
12
13 #include "exim.h"
14
15
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
19
20 #ifdef USE_TCP_WRAPPERS
21
22 #if HAVE_IPV6
23 #define EXIM_HAVE_IPV6
24 #endif
25 #undef HAVE_IPV6
26 #include <tcpd.h>
27 #undef HAVE_IPV6
28 #ifdef EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
30 #endif
31
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
34 #endif
35
36
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. */
41
42 #define smtp_cmd_buffer_size 2048
43
44 /* Size of buffer for reading SMTP incoming packets */
45
46 #define in_buffer_size 8192
47
48 /* Structure for SMTP command list */
49
50 typedef struct {
51 char *name;
52 int len;
53 short int cmd;
54 short int has_arg;
55 short int is_mail_cmd;
56 } smtp_cmd_list;
57
58 /* Codes for identifying commands. We order them so that those that come first
59 are those for which synchronization is always required. Checking this can help
60 block some spam. */
61
62 enum {
63 /* These commands are required to be synchronized, i.e. to be the last in a
64 block of commands when pipelining. */
65
66 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
67 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
68 ETRN_CMD, /* This by analogy with TURN from the RFC */
69 STARTTLS_CMD, /* Required by the STARTTLS RFC */
70
71 /* This is a dummy to identify the non-sync commands when pipelining */
72
73 NON_SYNC_CMD_PIPELINING,
74
75 /* These commands need not be synchronized when pipelining */
76
77 MAIL_CMD, RCPT_CMD, RSET_CMD,
78
79 /* This is a dummy to identify the non-sync commands when not pipelining */
80
81 NON_SYNC_CMD_NON_PIPELINING,
82
83 /* I have been unable to find a statement about the use of pipelining
84 with AUTH, so to be on the safe side it is here, though I kind of feel
85 it should be up there with the synchronized commands. */
86
87 AUTH_CMD,
88
89 /* I'm not sure about these, but I don't think they matter. */
90
91 QUIT_CMD, HELP_CMD,
92
93 /* These are specials that don't correspond to actual commands */
94
95 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
96 TOO_MANY_NONMAIL_CMD };
97
98
99
100 /*************************************************
101 * Local static variables *
102 *************************************************/
103
104 static auth_instance *authenticated_by;
105 static BOOL auth_advertised;
106 #ifdef SUPPORT_TLS
107 static BOOL tls_advertised;
108 #endif
109 static BOOL esmtp;
110 static BOOL helo_required = FALSE;
111 static BOOL helo_verify = FALSE;
112 static BOOL helo_seen;
113 static BOOL helo_accept_junk;
114 static BOOL count_nonmail;
115 static BOOL pipelining_advertised;
116 static int nonmail_command_count;
117 static int synprot_error_count;
118 static int unknown_command_count;
119 static int sync_cmd_limit;
120 static int smtp_write_error = 0;
121
122 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
123 final fields of all except AUTH are forced TRUE at the start of a new message
124 setup, to allow one of each between messages that is not counted as a nonmail
125 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
126 allow a new EHLO after starting up TLS.
127
128 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
129 counted. However, the flag is changed when AUTH is received, so that multiple
130 failing AUTHs will eventually hit the limit. After a successful AUTH, another
131 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
132 forced TRUE, to allow for the re-authentication that can happen at that point.
133
134 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
135 count of non-mail commands and possibly provoke an error. */
136
137 static smtp_cmd_list cmd_list[] = {
138 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
139 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
140 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
141 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
142 #ifdef SUPPORT_TLS
143 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
144 #endif
145
146 /* If you change anything above here, also fix the definitions below. */
147
148 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
149 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
150 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
151 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
152 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
153 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
154 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
155 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
156 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
157 };
158
159 static smtp_cmd_list *cmd_list_end =
160 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
161
162 #define CMD_LIST_RSET 0
163 #define CMD_LIST_HELO 1
164 #define CMD_LIST_EHLO 2
165 #define CMD_LIST_AUTH 3
166 #define CMD_LIST_STARTTLS 4
167
168 static uschar *protocols[] = {
169 US"local-smtp", /* HELO */
170 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
171 US"local-esmtp", /* EHLO */
172 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
173 US"local-esmtpa", /* EHLO->AUTH */
174 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
175 };
176
177 #define pnormal 0
178 #define pextend 2
179 #define pcrpted 1 /* added to pextend or pnormal */
180 #define pauthed 2 /* added to pextend */
181 #define pnlocal 6 /* offset to remove "local" */
182
183 /* When reading SMTP from a remote host, we have to use our own versions of the
184 C input-reading functions, in order to be able to flush the SMTP output only
185 when about to read more data from the socket. This is the only way to get
186 optimal performance when the client is using pipelining. Flushing for every
187 command causes a separate packet and reply packet each time; saving all the
188 responses up (when pipelining) combines them into one packet and one response.
189
190 For simplicity, these functions are used for *all* SMTP input, not only when
191 receiving over a socket. However, after setting up a secure socket (SSL), input
192 is read via the OpenSSL library, and another set of functions is used instead
193 (see tls.c).
194
195 These functions are set in the receive_getc etc. variables and called with the
196 same interface as the C functions. However, since there can only ever be
197 one incoming SMTP call, we just use a single buffer and flags. There is no need
198 to implement a complicated private FILE-like structure.*/
199
200 static uschar *smtp_inbuffer;
201 static uschar *smtp_inptr;
202 static uschar *smtp_inend;
203 static int smtp_had_eof;
204 static int smtp_had_error;
205
206
207 /*************************************************
208 * SMTP version of getc() *
209 *************************************************/
210
211 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
212 it flushes the output, and refills the buffer, with a timeout. The signal
213 handler is set appropriately by the calling function. This function is not used
214 after a connection has negotated itself into an TLS/SSL state.
215
216 Arguments: none
217 Returns: the next character or EOF
218 */
219
220 int
221 smtp_getc(void)
222 {
223 if (smtp_inptr >= smtp_inend)
224 {
225 int rc, save_errno;
226 fflush(smtp_out);
227 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
228 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
229 save_errno = errno;
230 alarm(0);
231 if (rc <= 0)
232 {
233 /* Must put the error text in fixed store, because this might be during
234 header reading, where it releases unused store above the header. */
235 if (rc < 0)
236 {
237 smtp_had_error = save_errno;
238 smtp_read_error = string_copy_malloc(
239 string_sprintf(" (error: %s)", strerror(save_errno)));
240 }
241 else smtp_had_eof = 1;
242 return EOF;
243 }
244 smtp_inend = smtp_inbuffer + rc;
245 smtp_inptr = smtp_inbuffer;
246 }
247 return *smtp_inptr++;
248 }
249
250
251
252 /*************************************************
253 * SMTP version of ungetc() *
254 *************************************************/
255
256 /* Puts a character back in the input buffer. Only ever
257 called once.
258
259 Arguments:
260 ch the character
261
262 Returns: the character
263 */
264
265 int
266 smtp_ungetc(int ch)
267 {
268 *(--smtp_inptr) = ch;
269 return ch;
270 }
271
272
273
274
275 /*************************************************
276 * SMTP version of feof() *
277 *************************************************/
278
279 /* Tests for a previous EOF
280
281 Arguments: none
282 Returns: non-zero if the eof flag is set
283 */
284
285 int
286 smtp_feof(void)
287 {
288 return smtp_had_eof;
289 }
290
291
292
293
294 /*************************************************
295 * SMTP version of ferror() *
296 *************************************************/
297
298 /* Tests for a previous read error, and returns with errno
299 restored to what it was when the error was detected.
300
301 Arguments: none
302 Returns: non-zero if the error flag is set
303 */
304
305 int
306 smtp_ferror(void)
307 {
308 errno = smtp_had_error;
309 return smtp_had_error;
310 }
311
312
313
314
315 /*************************************************
316 * Write formatted string to SMTP channel *
317 *************************************************/
318
319 /* This is a separate function so that we don't have to repeat everything for
320 TLS support or debugging. It is global so that the daemon and the
321 authentication functions can use it. It does not return any error indication,
322 because major problems such as dropped connections won't show up till an output
323 flush for non-TLS connections. The smtp_fflush() function is available for
324 checking that: for convenience, TLS output errors are remembered here so that
325 they are also picked up later by smtp_fflush().
326
327 Arguments:
328 format format string
329 ... optional arguments
330
331 Returns: nothing
332 */
333
334 void
335 smtp_printf(char *format, ...)
336 {
337 va_list ap;
338
339 DEBUG(D_receive)
340 {
341 va_start(ap, format);
342 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
343 debug_printf("SMTP>> %s", big_buffer);
344 }
345
346 va_start(ap, format);
347
348 /* If in a TLS session we have to format the string, and then write it using a
349 TLS function. */
350
351 #ifdef SUPPORT_TLS
352 if (tls_active >= 0)
353 {
354 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
355 {
356 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
357 smtp_closedown(US"Unexpected error");
358 exim_exit(EXIT_FAILURE);
359 }
360 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
361 }
362 else
363 #endif
364
365 /* Otherwise, just use the standard library function. */
366
367 if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
368 va_end(ap);
369 }
370
371
372
373 /*************************************************
374 * Flush SMTP out and check for error *
375 *************************************************/
376
377 /* This function isn't currently used within Exim (it detects errors when it
378 tries to read the next SMTP input), but is available for use in local_scan().
379 For non-TLS connections, it flushes the output and checks for errors. For
380 TLS-connections, it checks for a previously-detected TLS write error.
381
382 Arguments: none
383 Returns: 0 for no error; -1 after an error
384 */
385
386 int
387 smtp_fflush(void)
388 {
389 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
390 return smtp_write_error;
391 }
392
393
394
395 /*************************************************
396 * SMTP command read timeout *
397 *************************************************/
398
399 /* Signal handler for timing out incoming SMTP commands. This attempts to
400 finish off tidily.
401
402 Argument: signal number (SIGALRM)
403 Returns: nothing
404 */
405
406 static void
407 command_timeout_handler(int sig)
408 {
409 sig = sig; /* Keep picky compilers happy */
410 log_write(L_lost_incoming_connection,
411 LOG_MAIN, "SMTP command timeout on%s connection from %s",
412 (tls_active >= 0)? " TLS" : "",
413 host_and_ident(FALSE));
414 if (smtp_batched_input)
415 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
416 smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
417 smtp_active_hostname);
418 mac_smtp_fflush();
419 exim_exit(EXIT_FAILURE);
420 }
421
422
423
424 /*************************************************
425 * SIGTERM received *
426 *************************************************/
427
428 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
429
430 Argument: signal number (SIGTERM)
431 Returns: nothing
432 */
433
434 static void
435 command_sigterm_handler(int sig)
436 {
437 sig = sig; /* Keep picky compilers happy */
438 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
439 if (smtp_batched_input)
440 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
441 smtp_printf("421 %s: Service not available - closing connection\r\n",
442 smtp_active_hostname);
443 exim_exit(EXIT_FAILURE);
444 }
445
446
447
448 /*************************************************
449 * Read one command line *
450 *************************************************/
451
452 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
453 There are sites that don't do this, and in any case internal SMTP probably
454 should check only for LF. Consequently, we check here for LF only. The line
455 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
456 an unknown command. The command is read into the global smtp_cmd_buffer so that
457 it is available via $smtp_command.
458
459 The character reading routine sets up a timeout for each block actually read
460 from the input (which may contain more than one command). We set up a special
461 signal handler that closes down the session on a timeout. Control does not
462 return when it runs.
463
464 Arguments:
465 check_sync if TRUE, check synchronization rules if global option is TRUE
466
467 Returns: a code identifying the command (enumerated above)
468 */
469
470 static int
471 smtp_read_command(BOOL check_sync)
472 {
473 int c;
474 int ptr = 0;
475 smtp_cmd_list *p;
476 BOOL hadnull = FALSE;
477
478 os_non_restarting_signal(SIGALRM, command_timeout_handler);
479
480 while ((c = (receive_getc)()) != '\n' && c != EOF)
481 {
482 if (ptr >= smtp_cmd_buffer_size)
483 {
484 os_non_restarting_signal(SIGALRM, sigalrm_handler);
485 return OTHER_CMD;
486 }
487 if (c == 0)
488 {
489 hadnull = TRUE;
490 c = '?';
491 }
492 smtp_cmd_buffer[ptr++] = c;
493 }
494
495 receive_linecount++; /* For BSMTP errors */
496 os_non_restarting_signal(SIGALRM, sigalrm_handler);
497
498 /* If hit end of file, return pseudo EOF command. Whether we have a
499 part-line already read doesn't matter, since this is an error state. */
500
501 if (c == EOF) return EOF_CMD;
502
503 /* Remove any CR and white space at the end of the line, and terminate the
504 string. */
505
506 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
507 smtp_cmd_buffer[ptr] = 0;
508
509 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
510
511 /* NULLs are not allowed in SMTP commands */
512
513 if (hadnull) return BADCHAR_CMD;
514
515 /* Scan command list and return identity, having set the data pointer
516 to the start of the actual data characters. Check for SMTP synchronization
517 if required. */
518
519 for (p = cmd_list; p < cmd_list_end; p++)
520 {
521 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0)
522 {
523 if (smtp_inptr < smtp_inend && /* Outstanding input */
524 p->cmd < sync_cmd_limit && /* Command should sync */
525 check_sync && /* Local flag set */
526 smtp_enforce_sync && /* Global flag set */
527 sender_host_address != NULL && /* Not local input */
528 !sender_host_notsocket) /* Really is a socket */
529 return BADSYN_CMD;
530
531 /* Point after the command, but don't skip over leading spaces till after
532 the following test, so that if it fails, the command name can easily be
533 logged. */
534
535 smtp_cmd_argument = smtp_cmd_buffer + p->len;
536
537 /* Count non-mail commands from those hosts that are controlled in this
538 way. The default is all hosts. We don't waste effort checking the list
539 until we get a non-mail command, but then cache the result to save checking
540 again. If there's a DEFER while checking the host, assume it's in the list.
541
542 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
543 start of each incoming message by fiddling with the value in the table. */
544
545 if (!p->is_mail_cmd)
546 {
547 if (count_nonmail == TRUE_UNSET) count_nonmail =
548 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
549 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
550 return TOO_MANY_NONMAIL_CMD;
551 }
552
553 /* Get the data pointer over leading spaces and return; if there is data
554 for a command that does not expect it, give the error centrally here. */
555
556 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
557 return (p->has_arg || *smtp_cmd_argument == 0)? p->cmd : BADARG_CMD;
558 }
559 }
560
561 /* Enforce synchronization for unknown commands */
562
563 if (smtp_inptr < smtp_inend && /* Outstanding input */
564 check_sync && /* Local flag set */
565 smtp_enforce_sync && /* Global flag set */
566 sender_host_address != NULL && /* Not local input */
567 !sender_host_notsocket) /* Really is a socket */
568 return BADSYN_CMD;
569
570 return OTHER_CMD;
571 }
572
573
574
575 /*************************************************
576 * Forced closedown of call *
577 *************************************************/
578
579 /* This function is called from log.c when Exim is dying because of a serious
580 disaster, and also from some other places. If an incoming non-batched SMTP
581 channel is open, it swallows the rest of the incoming message if in the DATA
582 phase, sends the reply string, and gives an error to all subsequent commands
583 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
584 smtp_in.
585
586 Argument: SMTP reply string to send, excluding the code
587 Returns: nothing
588 */
589
590 void
591 smtp_closedown(uschar *message)
592 {
593 if (smtp_in == NULL || smtp_batched_input) return;
594 receive_swallow_smtp();
595 smtp_printf("421 %s\r\n", message);
596
597 for (;;)
598 {
599 switch(smtp_read_command(FALSE))
600 {
601 case EOF_CMD:
602 return;
603
604 case QUIT_CMD:
605 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
606 mac_smtp_fflush();
607 return;
608
609 case RSET_CMD:
610 smtp_printf("250 Reset OK\r\n");
611 break;
612
613 default:
614 smtp_printf("421 %s\r\n", message);
615 break;
616 }
617 }
618 }
619
620
621
622
623 /*************************************************
624 * Set up connection info for logging *
625 *************************************************/
626
627 /* This function is called when logging information about an SMTP connection.
628 It sets up appropriate source information, depending on the type of connection.
629
630 Argument: none
631 Returns: a string describing the connection
632 */
633
634 uschar *
635 smtp_get_connection_info(void)
636 {
637 if (host_checking)
638 return string_sprintf("SMTP connection from %s", sender_fullhost);
639
640 if (sender_host_unknown || sender_host_notsocket)
641 return string_sprintf("SMTP connection from %s", sender_ident);
642
643 if (is_inetd)
644 return string_sprintf("SMTP connection from %s (via inetd)", sender_fullhost);
645
646 if ((log_extra_selector & LX_incoming_interface) != 0 &&
647 interface_address != NULL)
648 return string_sprintf("SMTP connection from %s I=[%s]:%d", sender_fullhost,
649 interface_address, interface_port);
650
651 return string_sprintf("SMTP connection from %s", sender_fullhost);
652 }
653
654
655
656 /*************************************************
657 * Check HELO line and set sender_helo_name *
658 *************************************************/
659
660 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
661 the domain name of the sending host, or an ip literal in square brackets. The
662 arrgument is placed in sender_helo_name, which is in malloc store, because it
663 must persist over multiple incoming messages. If helo_accept_junk is set, this
664 host is permitted to send any old junk (needed for some broken hosts).
665 Otherwise, helo_allow_chars can be used for rogue characters in general
666 (typically people want to let in underscores).
667
668 Argument:
669 s the data portion of the line (already past any white space)
670
671 Returns: TRUE or FALSE
672 */
673
674 static BOOL
675 check_helo(uschar *s)
676 {
677 uschar *start = s;
678 uschar *end = s + Ustrlen(s);
679 BOOL yield = helo_accept_junk;
680
681 /* Discard any previous helo name */
682
683 if (sender_helo_name != NULL)
684 {
685 store_free(sender_helo_name);
686 sender_helo_name = NULL;
687 }
688
689 /* Skip tests if junk is permitted. */
690
691 if (!yield)
692 {
693 /* Allow the new standard form for IPv6 address literals, namely,
694 [IPv6:....], and because someone is bound to use it, allow an equivalent
695 IPv4 form. Allow plain addresses as well. */
696
697 if (*s == '[')
698 {
699 if (end[-1] == ']')
700 {
701 end[-1] = 0;
702 if (strncmpic(s, US"[IPv6:", 6) == 0)
703 yield = (string_is_ip_address(s+6, NULL) == 6);
704 else if (strncmpic(s, US"[IPv4:", 6) == 0)
705 yield = (string_is_ip_address(s+6, NULL) == 4);
706 else
707 yield = (string_is_ip_address(s+1, NULL) != 0);
708 end[-1] = ']';
709 }
710 }
711
712 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
713 that have been configured (usually underscore - sigh). */
714
715 else if (*s != 0)
716 {
717 yield = TRUE;
718 while (*s != 0)
719 {
720 if (!isalnum(*s) && *s != '.' && *s != '-' &&
721 Ustrchr(helo_allow_chars, *s) == NULL)
722 {
723 yield = FALSE;
724 break;
725 }
726 s++;
727 }
728 }
729 }
730
731 /* Save argument if OK */
732
733 if (yield) sender_helo_name = string_copy_malloc(start);
734 return yield;
735 }
736
737
738
739
740
741 /*************************************************
742 * Extract SMTP command option *
743 *************************************************/
744
745 /* This function picks the next option setting off the end of smtp_cmd_argument. It
746 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
747 things that can appear there.
748
749 Arguments:
750 name point this at the name
751 value point this at the data string
752
753 Returns: TRUE if found an option
754 */
755
756 static BOOL
757 extract_option(uschar **name, uschar **value)
758 {
759 uschar *n;
760 uschar *v = smtp_cmd_argument + Ustrlen(smtp_cmd_argument) -1;
761 while (isspace(*v)) v--;
762 v[1] = 0;
763
764 while (v > smtp_cmd_argument && *v != '=' && !isspace(*v)) v--;
765 if (*v != '=') return FALSE;
766
767 n = v;
768 while(isalpha(n[-1])) n--;
769
770 if (n[-1] != ' ') return FALSE;
771
772 n[-1] = 0;
773 *name = n;
774 *v++ = 0;
775 *value = v;
776 return TRUE;
777 }
778
779
780
781
782
783
784
785 /*************************************************
786 * Reset for new message *
787 *************************************************/
788
789 /* This function is called whenever the SMTP session is reset from
790 within either of the setup functions.
791
792 Argument: the stacking pool storage reset point
793 Returns: nothing
794 */
795
796 static void
797 smtp_reset(void *reset_point)
798 {
799 int i;
800 store_reset(reset_point);
801 recipients_list = NULL;
802 rcpt_count = rcpt_defer_count = rcpt_fail_count =
803 raw_recipients_count = recipients_count = recipients_list_max = 0;
804 message_linecount = 0;
805 message_size = -1;
806 acl_warn_headers = NULL;
807 queue_only_policy = FALSE;
808 deliver_freeze = FALSE; /* Can be set by ACL */
809 fake_response = OK; /* Can be set by ACL */
810 #ifdef WITH_CONTENT_SCAN
811 no_mbox_unspool = FALSE; /* Can be set by ACL */
812 #endif
813 submission_mode = FALSE; /* Can be set by ACL */
814 suppress_local_fixups = FALSE; /* Can be set by ACL */
815 active_local_from_check = local_from_check; /* Can be set by ACL */
816 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
817 sender_address = NULL;
818 submission_name = NULL; /* Can be set by ACL */
819 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
820 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
821 sender_verified_list = NULL; /* No senders verified */
822 memset(sender_address_cache, 0, sizeof(sender_address_cache));
823 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
824 authenticated_sender = NULL;
825 #ifdef EXPERIMENTAL_BRIGHTMAIL
826 bmi_run = 0;
827 bmi_verdicts = NULL;
828 #endif
829 #ifdef EXPERIMENTAL_DOMAINKEYS
830 dk_do_verify = 0;
831 #endif
832 #ifdef EXPERIMENTAL_SPF
833 spf_header_comment = NULL;
834 spf_received = NULL;
835 spf_result = NULL;
836 spf_smtp_comment = NULL;
837 #endif
838 body_linecount = body_zerocount = 0;
839
840 sender_rate = sender_rate_limit = sender_rate_period = NULL;
841 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
842 /* Note that ratelimiters_conn persists across resets. */
843
844 /* The message variables follow the connection variables. */
845
846 for (i = 0; i < ACL_MVARS; i++) acl_var[ACL_CVARS + i] = NULL;
847
848 /* The message body variables use malloc store. They may be set if this is
849 not the first message in an SMTP session and the previous message caused them
850 to be referenced in an ACL. */
851
852 if (message_body != NULL)
853 {
854 store_free(message_body);
855 message_body = NULL;
856 }
857
858 if (message_body_end != NULL)
859 {
860 store_free(message_body_end);
861 message_body_end = NULL;
862 }
863
864 /* Warning log messages are also saved in malloc store. They are saved to avoid
865 repetition in the same message, but it seems right to repeat them for different
866 messagess. */
867
868 while (acl_warn_logged != NULL)
869 {
870 string_item *this = acl_warn_logged;
871 acl_warn_logged = acl_warn_logged->next;
872 store_free(this);
873 }
874 }
875
876
877
878
879
880 /*************************************************
881 * Initialize for incoming batched SMTP message *
882 *************************************************/
883
884 /* This function is called from smtp_setup_msg() in the case when
885 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
886 of messages in one file with SMTP commands between them. All errors must be
887 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
888 relevant. After an error on a sender, or an invalid recipient, the remainder
889 of the message is skipped. The value of received_protocol is already set.
890
891 Argument: none
892 Returns: > 0 message successfully started (reached DATA)
893 = 0 QUIT read or end of file reached
894 < 0 should not occur
895 */
896
897 static int
898 smtp_setup_batch_msg(void)
899 {
900 int done = 0;
901 void *reset_point = store_get(0);
902
903 /* Save the line count at the start of each transaction - single commands
904 like HELO and RSET count as whole transactions. */
905
906 bsmtp_transaction_linecount = receive_linecount;
907
908 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
909
910 smtp_reset(reset_point); /* Reset for start of message */
911
912 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
913 value. The values are 2 larger than the required yield of the function. */
914
915 while (done <= 0)
916 {
917 uschar *errmess;
918 uschar *recipient = NULL;
919 int start, end, sender_domain, recipient_domain;
920
921 switch(smtp_read_command(FALSE))
922 {
923 /* The HELO/EHLO commands set sender_address_helo if they have
924 valid data; otherwise they are ignored, except that they do
925 a reset of the state. */
926
927 case HELO_CMD:
928 case EHLO_CMD:
929
930 check_helo(smtp_cmd_argument);
931 /* Fall through */
932
933 case RSET_CMD:
934 smtp_reset(reset_point);
935 bsmtp_transaction_linecount = receive_linecount;
936 break;
937
938
939 /* The MAIL FROM command requires an address as an operand. All we
940 do here is to parse it for syntactic correctness. The form "<>" is
941 a special case which converts into an empty string. The start/end
942 pointers in the original are not used further for this address, as
943 it is the canonical extracted address which is all that is kept. */
944
945 case MAIL_CMD:
946 if (sender_address != NULL)
947 /* The function moan_smtp_batch() does not return. */
948 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
949
950 if (smtp_cmd_argument[0] == 0)
951 /* The function moan_smtp_batch() does not return. */
952 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
953
954 /* Reset to start of message */
955
956 smtp_reset(reset_point);
957
958 /* Apply SMTP rewrite */
959
960 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
961 rewrite_one(smtp_cmd_argument, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
962 US"", global_rewrite_rules) : smtp_cmd_argument;
963
964 /* Extract the address; the TRUE flag allows <> as valid */
965
966 raw_sender =
967 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
968 TRUE);
969
970 if (raw_sender == NULL)
971 /* The function moan_smtp_batch() does not return. */
972 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
973
974 sender_address = string_copy(raw_sender);
975
976 /* Qualify unqualified sender addresses if permitted to do so. */
977
978 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
979 {
980 if (allow_unqualified_sender)
981 {
982 sender_address = rewrite_address_qualify(sender_address, FALSE);
983 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
984 "and rewritten\n", raw_sender);
985 }
986 /* The function moan_smtp_batch() does not return. */
987 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
988 "a domain");
989 }
990 break;
991
992
993 /* The RCPT TO command requires an address as an operand. All we do
994 here is to parse it for syntactic correctness. There may be any number
995 of RCPT TO commands, specifying multiple senders. We build them all into
996 a data structure that is in argc/argv format. The start/end values
997 given by parse_extract_address are not used, as we keep only the
998 extracted address. */
999
1000 case RCPT_CMD:
1001 if (sender_address == NULL)
1002 /* The function moan_smtp_batch() does not return. */
1003 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1004
1005 if (smtp_cmd_argument[0] == 0)
1006 /* The function moan_smtp_batch() does not return. */
1007 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1008
1009 /* Check maximum number allowed */
1010
1011 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1012 /* The function moan_smtp_batch() does not return. */
1013 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1014 recipients_max_reject? "552": "452");
1015
1016 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1017 recipient address */
1018
1019 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1020 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
1021 global_rewrite_rules) : smtp_cmd_argument;
1022
1023 /* rfc821_domains = TRUE; << no longer needed */
1024 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1025 &recipient_domain, FALSE);
1026 /* rfc821_domains = FALSE; << no longer needed */
1027
1028 if (recipient == NULL)
1029 /* The function moan_smtp_batch() does not return. */
1030 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1031
1032 /* If the recipient address is unqualified, qualify it if permitted. Then
1033 add it to the list of recipients. */
1034
1035 if (recipient_domain == 0)
1036 {
1037 if (allow_unqualified_recipient)
1038 {
1039 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1040 recipient);
1041 recipient = rewrite_address_qualify(recipient, TRUE);
1042 }
1043 /* The function moan_smtp_batch() does not return. */
1044 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1045 "a domain");
1046 }
1047 receive_add_recipient(recipient, -1);
1048 break;
1049
1050
1051 /* The DATA command is legal only if it follows successful MAIL FROM
1052 and RCPT TO commands. This function is complete when a valid DATA
1053 command is encountered. */
1054
1055 case DATA_CMD:
1056 if (sender_address == NULL || recipients_count <= 0)
1057 {
1058 /* The function moan_smtp_batch() does not return. */
1059 if (sender_address == NULL)
1060 moan_smtp_batch(smtp_cmd_buffer,
1061 "503 MAIL FROM:<sender> command must precede DATA");
1062 else
1063 moan_smtp_batch(smtp_cmd_buffer,
1064 "503 RCPT TO:<recipient> must precede DATA");
1065 }
1066 else
1067 {
1068 done = 3; /* DATA successfully achieved */
1069 message_ended = END_NOTENDED; /* Indicate in middle of message */
1070 }
1071 break;
1072
1073
1074 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1075
1076 case VRFY_CMD:
1077 case EXPN_CMD:
1078 case HELP_CMD:
1079 case NOOP_CMD:
1080 case ETRN_CMD:
1081 bsmtp_transaction_linecount = receive_linecount;
1082 break;
1083
1084
1085 case EOF_CMD:
1086 case QUIT_CMD:
1087 done = 2;
1088 break;
1089
1090
1091 case BADARG_CMD:
1092 /* The function moan_smtp_batch() does not return. */
1093 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1094 break;
1095
1096
1097 case BADCHAR_CMD:
1098 /* The function moan_smtp_batch() does not return. */
1099 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1100 break;
1101
1102
1103 default:
1104 /* The function moan_smtp_batch() does not return. */
1105 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1106 break;
1107 }
1108 }
1109
1110 return done - 2; /* Convert yield values */
1111 }
1112
1113
1114
1115
1116 /*************************************************
1117 * Start an SMTP session *
1118 *************************************************/
1119
1120 /* This function is called at the start of an SMTP session. Thereafter,
1121 smtp_setup_msg() is called to initiate each separate message. This
1122 function does host-specific testing, and outputs the banner line.
1123
1124 Arguments: none
1125 Returns: FALSE if the session can not continue; something has
1126 gone wrong, or the connection to the host is blocked
1127 */
1128
1129 BOOL
1130 smtp_start_session(void)
1131 {
1132 int size = 256;
1133 int i, ptr;
1134 uschar *p, *s, *ss;
1135
1136 /* If we are running in the test harness, and the incoming call is from
1137 127.0.0.2 (sic), have a short delay. This makes it possible to test handling of
1138 input sent too soon (before the banner is output). */
1139
1140 if (running_in_test_harness &&
1141 sender_host_address != NULL &&
1142 Ustrcmp(sender_host_address, "127.0.0.2") == 0)
1143 sleep(1);
1144
1145 /* Default values for certain variables */
1146
1147 helo_seen = esmtp = helo_accept_junk = FALSE;
1148 count_nonmail = TRUE_UNSET;
1149 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1150 smtp_delay_mail = smtp_rlm_base;
1151 auth_advertised = FALSE;
1152 pipelining_advertised = FALSE;
1153 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1154
1155 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1156
1157 sender_host_authenticated = NULL;
1158 authenticated_by = NULL;
1159
1160 #ifdef SUPPORT_TLS
1161 tls_cipher = tls_peerdn = NULL;
1162 tls_advertised = FALSE;
1163 #endif
1164
1165 /* Reset ACL connection variables */
1166
1167 for (i = 0; i < ACL_CVARS; i++) acl_var[i] = NULL;
1168
1169 /* Allow for trailing 0 in the command buffer. */
1170
1171 smtp_cmd_buffer = (uschar *)malloc(smtp_cmd_buffer_size + 1);
1172 if (smtp_cmd_buffer == NULL)
1173 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1174 "malloc() failed for SMTP command buffer");
1175
1176 /* For batched input, the protocol setting can be overridden from the
1177 command line by a trusted caller. */
1178
1179 if (smtp_batched_input)
1180 {
1181 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1182 }
1183
1184 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1185 reset later if any of EHLO/AUTH/STARTTLS are received. */
1186
1187 else
1188 received_protocol =
1189 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1190
1191 /* Set up the buffer for inputting using direct read() calls, and arrange to
1192 call the local functions instead of the standard C ones. */
1193
1194 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1195 if (smtp_inbuffer == NULL)
1196 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1197 receive_getc = smtp_getc;
1198 receive_ungetc = smtp_ungetc;
1199 receive_feof = smtp_feof;
1200 receive_ferror = smtp_ferror;
1201 smtp_inptr = smtp_inend = smtp_inbuffer;
1202 smtp_had_eof = smtp_had_error = 0;
1203
1204 /* Set up the message size limit; this may be host-specific */
1205
1206 thismessage_size_limit = expand_string_integer(message_size_limit);
1207 if (thismessage_size_limit < 0)
1208 {
1209 if (thismessage_size_limit == -1)
1210 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1211 "%s", expand_string_message);
1212 else
1213 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1214 "%s", expand_string_message);
1215 smtp_closedown(US"Temporary local problem - please try later");
1216 return FALSE;
1217 }
1218
1219 /* When a message is input locally via the -bs or -bS options, sender_host_
1220 unknown is set unless -oMa was used to force an IP address, in which case it
1221 is checked like a real remote connection. When -bs is used from inetd, this
1222 flag is not set, causing the sending host to be checked. The code that deals
1223 with IP source routing (if configured) is never required for -bs or -bS and
1224 the flag sender_host_notsocket is used to suppress it.
1225
1226 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1227 reserve for certain hosts and/or networks. */
1228
1229 if (!sender_host_unknown)
1230 {
1231 int rc;
1232 BOOL reserved_host = FALSE;
1233
1234 /* Look up IP options (source routing info) on the socket if this is not an
1235 -oMa "host", and if any are found, log them and drop the connection.
1236
1237 Linux (and others now, see below) is different to everyone else, so there
1238 has to be some conditional compilation here. Versions of Linux before 2.1.15
1239 used a structure whose name was "options". Somebody finally realized that
1240 this name was silly, and it got changed to "ip_options". I use the
1241 newer name here, but there is a fudge in the script that sets up os.h
1242 to define a macro in older Linux systems.
1243
1244 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1245 glibc 2, which has chosen ip_opts for the structure name. This is now
1246 really a glibc thing rather than a Linux thing, so the condition name
1247 has been changed to reflect this. It is relevant also to GNU/Hurd.
1248
1249 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1250 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1251 a special macro defined in the os.h file.
1252
1253 Some DGUX versions on older hardware appear not to support IP options at
1254 all, so there is now a general macro which can be set to cut out this
1255 support altogether.
1256
1257 How to do this properly in IPv6 is not yet known. */
1258
1259 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1260
1261 #ifdef GLIBC_IP_OPTIONS
1262 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1263 #define OPTSTYLE 1
1264 #else
1265 #define OPTSTYLE 2
1266 #endif
1267 #elif defined DARWIN_IP_OPTIONS
1268 #define OPTSTYLE 2
1269 #else
1270 #define OPTSTYLE 3
1271 #endif
1272
1273 if (!host_checking && !sender_host_notsocket)
1274 {
1275 #if OPTSTYLE == 1
1276 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1277 struct ip_options *ipopt = store_get(optlen);
1278 #elif OPTSTYLE == 2
1279 struct ip_opts ipoptblock;
1280 struct ip_opts *ipopt = &ipoptblock;
1281 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1282 #else
1283 struct ipoption ipoptblock;
1284 struct ipoption *ipopt = &ipoptblock;
1285 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1286 #endif
1287
1288 /* Occasional genuine failures of getsockopt() have been seen - for
1289 example, "reset by peer". Therefore, just log and give up on this
1290 call, unless the error is ENOPROTOOPT. This error is given by systems
1291 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1292 of writing. So for that error, carry on - we just can't do an IP options
1293 check. */
1294
1295 DEBUG(D_receive) debug_printf("checking for IP options\n");
1296
1297 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1298 &optlen) < 0)
1299 {
1300 if (errno != ENOPROTOOPT)
1301 {
1302 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1303 host_and_ident(FALSE), strerror(errno));
1304 smtp_printf("451 SMTP service not available\r\n");
1305 return FALSE;
1306 }
1307 }
1308
1309 /* Deal with any IP options that are set. On the systems I have looked at,
1310 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1311 more logging data than will fit in big_buffer. Nevertheless, after somebody
1312 questioned this code, I've added in some paranoid checking. */
1313
1314 else if (optlen > 0)
1315 {
1316 uschar *p = big_buffer;
1317 uschar *pend = big_buffer + big_buffer_size;
1318 uschar *opt, *adptr;
1319 int optcount;
1320 struct in_addr addr;
1321
1322 #if OPTSTYLE == 1
1323 uschar *optstart = (uschar *)(ipopt->__data);
1324 #elif OPTSTYLE == 2
1325 uschar *optstart = (uschar *)(ipopt->ip_opts);
1326 #else
1327 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1328 #endif
1329
1330 DEBUG(D_receive) debug_printf("IP options exist\n");
1331
1332 Ustrcpy(p, "IP options on incoming call:");
1333 p += Ustrlen(p);
1334
1335 for (opt = optstart; opt != NULL &&
1336 opt < (uschar *)(ipopt) + optlen;)
1337 {
1338 switch (*opt)
1339 {
1340 case IPOPT_EOL:
1341 opt = NULL;
1342 break;
1343
1344 case IPOPT_NOP:
1345 opt++;
1346 break;
1347
1348 case IPOPT_SSRR:
1349 case IPOPT_LSRR:
1350 if (!string_format(p, pend-p, " %s [@%s",
1351 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1352 #if OPTSTYLE == 1
1353 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1354 #elif OPTSTYLE == 2
1355 inet_ntoa(ipopt->ip_dst)))
1356 #else
1357 inet_ntoa(ipopt->ipopt_dst)))
1358 #endif
1359 {
1360 opt = NULL;
1361 break;
1362 }
1363
1364 p += Ustrlen(p);
1365 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1366 adptr = opt + 3;
1367 while (optcount-- > 0)
1368 {
1369 memcpy(&addr, adptr, sizeof(addr));
1370 if (!string_format(p, pend - p - 1, "%s%s",
1371 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1372 {
1373 opt = NULL;
1374 break;
1375 }
1376 p += Ustrlen(p);
1377 adptr += sizeof(struct in_addr);
1378 }
1379 *p++ = ']';
1380 opt += opt[1];
1381 break;
1382
1383 default:
1384 {
1385 int i;
1386 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1387 Ustrcat(p, "[ ");
1388 p += 2;
1389 for (i = 0; i < opt[1]; i++)
1390 {
1391 sprintf(CS p, "%2.2x ", opt[i]);
1392 p += 3;
1393 }
1394 *p++ = ']';
1395 }
1396 opt += opt[1];
1397 break;
1398 }
1399 }
1400
1401 *p = 0;
1402 log_write(0, LOG_MAIN, "%s", big_buffer);
1403
1404 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1405
1406 log_write(0, LOG_MAIN|LOG_REJECT,
1407 "connection from %s refused (IP options)", host_and_ident(FALSE));
1408
1409 smtp_printf("554 SMTP service not available\r\n");
1410 return FALSE;
1411 }
1412
1413 /* Length of options = 0 => there are no options */
1414
1415 else DEBUG(D_receive) debug_printf("no IP options found\n");
1416 }
1417 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1418
1419 /* Set keep-alive in socket options. The option is on by default. This
1420 setting is an attempt to get rid of some hanging connections that stick in
1421 read() when the remote end (usually a dialup) goes away. */
1422
1423 if (smtp_accept_keepalive && !sender_host_notsocket)
1424 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1425
1426 /* If the current host matches host_lookup, set the name by doing a
1427 reverse lookup. On failure, sender_host_name will be NULL and
1428 host_lookup_failed will be TRUE. This may or may not be serious - optional
1429 checks later. */
1430
1431 if (verify_check_host(&host_lookup) == OK)
1432 {
1433 (void)host_name_lookup();
1434 host_build_sender_fullhost();
1435 }
1436
1437 /* Delay this until we have the full name, if it is looked up. */
1438
1439 set_process_info("handling incoming connection from %s",
1440 host_and_ident(FALSE));
1441
1442 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1443 smtps port for use with older style SSL MTAs. */
1444
1445 #ifdef SUPPORT_TLS
1446 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1447 return FALSE;
1448 #endif
1449
1450 /* Test for explicit connection rejection */
1451
1452 if (verify_check_host(&host_reject_connection) == OK)
1453 {
1454 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1455 "from %s (host_reject_connection)", host_and_ident(FALSE));
1456 smtp_printf("554 SMTP service not available\r\n");
1457 return FALSE;
1458 }
1459
1460 /* Test with TCP Wrappers if so configured */
1461
1462 #ifdef USE_TCP_WRAPPERS
1463 if (!hosts_ctl("exim",
1464 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1465 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1466 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1467 {
1468 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1469 log_write(L_connection_reject,
1470 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1471 "(tcp wrappers)", host_and_ident(FALSE));
1472 smtp_printf("554 SMTP service not available\r\n");
1473 return FALSE;
1474 }
1475 #endif
1476
1477 /* Check for reserved slots. Note that the count value doesn't include
1478 this process, as it gets upped in the parent process. */
1479
1480 if (smtp_accept_max > 0 &&
1481 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1482 {
1483 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1484 {
1485 log_write(L_connection_reject,
1486 LOG_MAIN, "temporarily refused connection from %s: not in "
1487 "reserve list: connected=%d max=%d reserve=%d%s",
1488 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1489 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1490 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1491 "please try again later\r\n", smtp_active_hostname);
1492 return FALSE;
1493 }
1494 reserved_host = TRUE;
1495 }
1496
1497 /* If a load level above which only messages from reserved hosts are
1498 accepted is set, check the load. For incoming calls via the daemon, the
1499 check is done in the superior process if there are no reserved hosts, to
1500 save a fork. In all cases, the load average will already be available
1501 in a global variable at this point. */
1502
1503 if (smtp_load_reserve >= 0 &&
1504 load_average > smtp_load_reserve &&
1505 !reserved_host &&
1506 verify_check_host(&smtp_reserve_hosts) != OK)
1507 {
1508 log_write(L_connection_reject,
1509 LOG_MAIN, "temporarily refused connection from %s: not in "
1510 "reserve list and load average = %.2f", host_and_ident(FALSE),
1511 (double)load_average/1000.0);
1512 smtp_printf("421 %s: Too much load; please try again later\r\n",
1513 smtp_active_hostname);
1514 return FALSE;
1515 }
1516
1517 /* Determine whether unqualified senders or recipients are permitted
1518 for this host. Unfortunately, we have to do this every time, in order to
1519 set the flags so that they can be inspected when considering qualifying
1520 addresses in the headers. For a site that permits no qualification, this
1521 won't take long, however. */
1522
1523 allow_unqualified_sender =
1524 verify_check_host(&sender_unqualified_hosts) == OK;
1525
1526 allow_unqualified_recipient =
1527 verify_check_host(&recipient_unqualified_hosts) == OK;
1528
1529 /* Determine whether HELO/EHLO is required for this host. The requirement
1530 can be hard or soft. */
1531
1532 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1533 if (!helo_required)
1534 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1535
1536 /* Determine whether this hosts is permitted to send syntactic junk
1537 after a HELO or EHLO command. */
1538
1539 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1540 }
1541
1542 /* For batch SMTP input we are now done. */
1543
1544 if (smtp_batched_input) return TRUE;
1545
1546 /* Run the ACL if it exists */
1547
1548 if (acl_smtp_connect != NULL)
1549 {
1550 int rc;
1551 uschar *user_msg, *log_msg;
1552 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1553 &log_msg);
1554 if (rc != OK)
1555 {
1556 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1557 return FALSE;
1558 }
1559 }
1560
1561 /* Output the initial message for a two-way SMTP connection. It may contain
1562 newlines, which then cause a multi-line response to be given. */
1563
1564 s = expand_string(smtp_banner);
1565 if (s == NULL)
1566 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1567 "failed: %s", smtp_banner, expand_string_message);
1568
1569 /* Remove any terminating newlines; might as well remove trailing space too */
1570
1571 p = s + Ustrlen(s);
1572 while (p > s && isspace(p[-1])) p--;
1573 *p = 0;
1574
1575 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1576 is all contained in a single IP packet. The original code wrote out the
1577 greeting using several calls to fprint/fputc, and on busy servers this could
1578 cause it to be split over more than one packet - which caused CC:Mail to fall
1579 over when it got the second part of the greeting after sending its first
1580 command. Sigh. To try to avoid this, build the complete greeting message
1581 first, and output it in one fell swoop. This gives a better chance of it
1582 ending up as a single packet. */
1583
1584 ss = store_get(size);
1585 ptr = 0;
1586
1587 p = s;
1588 do /* At least once, in case we have an empty string */
1589 {
1590 int len;
1591 uschar *linebreak = Ustrchr(p, '\n');
1592 if (linebreak == NULL)
1593 {
1594 len = Ustrlen(p);
1595 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1596 }
1597 else
1598 {
1599 len = linebreak - p;
1600 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1601 }
1602 ss = string_cat(ss, &size, &ptr, p, len);
1603 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1604 p += len;
1605 if (linebreak != NULL) p++;
1606 }
1607 while (*p != 0);
1608
1609 ss[ptr] = 0; /* string_cat leaves room for this */
1610
1611 /* Before we write the banner, check that there is no input pending, unless
1612 this synchronisation check is disabled. */
1613
1614 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1615 {
1616 fd_set fds;
1617 struct timeval tzero;
1618 tzero.tv_sec = 0;
1619 tzero.tv_usec = 0;
1620 FD_ZERO(&fds);
1621 FD_SET(fileno(smtp_in), &fds);
1622 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1623 &tzero) > 0)
1624 {
1625 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1626 if (rc > 0)
1627 {
1628 if (rc > 150) rc = 150;
1629 smtp_inbuffer[rc] = 0;
1630 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1631 "synchronization error (input sent without waiting for greeting): "
1632 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1633 string_printing(smtp_inbuffer));
1634 smtp_printf("554 SMTP synchronization error\r\n");
1635 return FALSE;
1636 }
1637 }
1638 }
1639
1640 /* Now output the banner */
1641
1642 smtp_printf("%s", ss);
1643 return TRUE;
1644 }
1645
1646
1647
1648
1649
1650 /*************************************************
1651 * Handle SMTP syntax and protocol errors *
1652 *************************************************/
1653
1654 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1655 to do so. Then transmit the error response. The return value depends on the
1656 number of syntax and protocol errors in this SMTP session.
1657
1658 Arguments:
1659 type error type, given as a log flag bit
1660 code response code; <= 0 means don't send a response
1661 data data to reflect in the response (can be NULL)
1662 errmess the error message
1663
1664 Returns: -1 limit of syntax/protocol errors NOT exceeded
1665 +1 limit of syntax/protocol errors IS exceeded
1666
1667 These values fit in with the values of the "done" variable in the main
1668 processing loop in smtp_setup_msg(). */
1669
1670 static int
1671 synprot_error(int type, int code, uschar *data, uschar *errmess)
1672 {
1673 int yield = -1;
1674
1675 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1676 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1677 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1678
1679 if (++synprot_error_count > smtp_max_synprot_errors)
1680 {
1681 yield = 1;
1682 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1683 "syntax or protocol errors (last command was \"%s\")",
1684 host_and_ident(FALSE), smtp_cmd_buffer);
1685 }
1686
1687 if (code > 0)
1688 {
1689 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1690 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1691 if (yield == 1)
1692 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1693 }
1694
1695 return yield;
1696 }
1697
1698
1699
1700
1701 /*************************************************
1702 * Log incomplete transactions *
1703 *************************************************/
1704
1705 /* This function is called after a transaction has been aborted by RSET, QUIT,
1706 connection drops or other errors. It logs the envelope information received
1707 so far in order to preserve address verification attempts.
1708
1709 Argument: string to indicate what aborted the transaction
1710 Returns: nothing
1711 */
1712
1713 static void
1714 incomplete_transaction_log(uschar *what)
1715 {
1716 if (sender_address == NULL || /* No transaction in progress */
1717 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1718 ) return;
1719
1720 /* Build list of recipients for logging */
1721
1722 if (recipients_count > 0)
1723 {
1724 int i;
1725 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1726 for (i = 0; i < recipients_count; i++)
1727 raw_recipients[i] = recipients_list[i].address;
1728 raw_recipients_count = recipients_count;
1729 }
1730
1731 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1732 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1733 }
1734
1735
1736
1737
1738 /*************************************************
1739 * Send SMTP response, possibly multiline *
1740 *************************************************/
1741
1742 /* There are, it seems, broken clients out there that cannot handle multiline
1743 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1744 output nothing for non-final calls, and only the first line for anything else.
1745
1746 Arguments:
1747 code SMTP code
1748 final FALSE if the last line isn't the final line
1749 msg message text, possibly containing newlines
1750
1751 Returns: nothing
1752 */
1753
1754 void
1755 smtp_respond(int code, BOOL final, uschar *msg)
1756 {
1757 if (!final && no_multiline_responses) return;
1758
1759 for (;;)
1760 {
1761 uschar *nl = Ustrchr(msg, '\n');
1762 if (nl == NULL)
1763 {
1764 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1765 return;
1766 }
1767 else if (nl[1] == 0 || no_multiline_responses)
1768 {
1769 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1770 return;
1771 }
1772 else
1773 {
1774 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1775 msg = nl + 1;
1776 while (isspace(*msg)) msg++;
1777 }
1778 }
1779 }
1780
1781
1782
1783
1784 /*************************************************
1785 * Handle an ACL failure *
1786 *************************************************/
1787
1788 /* This function is called when acl_check() fails. As well as calls from within
1789 this module, it is called from receive.c for an ACL after DATA. It sorts out
1790 logging the incident, and sets up the error response. A message containing
1791 newlines is turned into a multiline SMTP response, but for logging, only the
1792 first line is used.
1793
1794 There's a table of the response codes to use in globals.c, along with the table
1795 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1796 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1797 that the response should be 252 in the disabled state, because there are broken
1798 clients that try VRFY before RCPT. A 5xx response should be given only when the
1799 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1800 given on refusal, and for AUTH, 503.
1801
1802 Arguments:
1803 where where the ACL was called from
1804 rc the failure code
1805 user_msg a message that can be included in an SMTP response
1806 log_msg a message for logging
1807
1808 Returns: 0 in most cases
1809 2 if the failure code was FAIL_DROP, in which case the
1810 SMTP connection should be dropped (this value fits with the
1811 "done" variable in smtp_setup_msg() below)
1812 */
1813
1814 int
1815 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1816 {
1817 int code = acl_wherecodes[where];
1818 BOOL drop = rc == FAIL_DROP;
1819 uschar *lognl;
1820 uschar *sender_info = US"";
1821 uschar *what =
1822 #ifdef WITH_CONTENT_SCAN
1823 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1824 #endif
1825 (where == ACL_WHERE_PREDATA)? US"DATA" :
1826 (where == ACL_WHERE_DATA)? US"after DATA" :
1827 (smtp_cmd_argument == NULL)?
1828 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
1829 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_argument);
1830
1831 if (drop) rc = FAIL;
1832
1833 /* We used to have sender_address here; however, there was a bug that was not
1834 updating sender_address after a rewrite during a verify. When this bug was
1835 fixed, sender_address at this point became the rewritten address. I'm not sure
1836 this is what should be logged, so I've changed to logging the unrewritten
1837 address to retain backward compatibility. */
1838
1839 #ifndef WITH_CONTENT_SCAN
1840 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1841 #else
1842 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1843 #endif
1844 {
1845 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1846 sender_address_unrewritten : sender_address);
1847 }
1848
1849 /* If there's been a sender verification failure with a specific message, and
1850 we have not sent a response about it yet, do so now, as a preliminary line for
1851 failures, but not defers. However, log it in both cases. */
1852
1853 if (sender_verified_failed != NULL &&
1854 !testflag(sender_verified_failed, af_sverify_told))
1855 {
1856 setflag(sender_verified_failed, af_sverify_told);
1857
1858 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1859 host_and_ident(TRUE),
1860 ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail",
1861 sender_verified_failed->address,
1862 (sender_verified_failed->message == NULL)? US"" :
1863 string_sprintf(": %s", sender_verified_failed->message));
1864
1865 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1866 smtp_respond(code, FALSE, string_sprintf(
1867 testflag(sender_verified_failed, af_verify_pmfail)?
1868 "Postmaster verification failed while checking <%s>\n%s\n"
1869 "Several RFCs state that you are required to have a postmaster\n"
1870 "mailbox for each mail domain. This host does not accept mail\n"
1871 "from domains whose servers reject the postmaster address."
1872 :
1873 testflag(sender_verified_failed, af_verify_nsfail)?
1874 "Callback setup failed while verifying <%s>\n%s\n"
1875 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1876 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1877 "RFC requirements, and stops you from receiving standard bounce\n"
1878 "messages. This host does not accept mail from domains whose servers\n"
1879 "refuse bounces."
1880 :
1881 "Verification failed for <%s>\n%s",
1882 sender_verified_failed->address,
1883 sender_verified_failed->user_message));
1884 }
1885
1886 /* Sort out text for logging */
1887
1888 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1889 lognl = Ustrchr(log_msg, '\n');
1890 if (lognl != NULL) *lognl = 0;
1891
1892 /* Send permanent failure response to the command, but the code used isn't
1893 always a 5xx one - see comments at the start of this function. If the original
1894 rc was FAIL_DROP we drop the connection and yield 2. */
1895
1896 if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1897 US"Administrative prohibition" : user_msg);
1898
1899 /* Send temporary failure response to the command. Don't give any details,
1900 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1901 verb, and for a header verify when smtp_return_error_details is set.
1902
1903 This conditional logic is all somewhat of a mess because of the odd
1904 interactions between temp_details and return_error_details. One day it should
1905 be re-implemented in a tidier fashion. */
1906
1907 else
1908 {
1909 if (acl_temp_details && user_msg != NULL)
1910 {
1911 if (smtp_return_error_details &&
1912 sender_verified_failed != NULL &&
1913 sender_verified_failed->message != NULL)
1914 {
1915 smtp_respond(451, FALSE, sender_verified_failed->message);
1916 }
1917 smtp_respond(451, TRUE, user_msg);
1918 }
1919 else
1920 smtp_printf("451 Temporary local problem - please try later\r\n");
1921 }
1922
1923 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
1924 Otherwise, log why it is closing if required and return 2. */
1925
1926 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1927 host_and_ident(TRUE),
1928 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1929
1930 if (!drop) return 0;
1931
1932 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1933 smtp_get_connection_info());
1934 return 2;
1935 }
1936
1937
1938
1939
1940 /*************************************************
1941 * Verify HELO argument *
1942 *************************************************/
1943
1944 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
1945 matched. It is also called from ACL processing if verify = helo is used and
1946 verification was not previously tried (i.e. helo_try_verify_hosts was not
1947 matched). The result of its processing is to set helo_verified and
1948 helo_verify_failed. These variables should both be FALSE for this function to
1949 be called.
1950
1951 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
1952 for IPv6 ::ffff: literals.
1953
1954 Argument: none
1955 Returns: TRUE if testing was completed;
1956 FALSE on a temporary failure
1957 */
1958
1959 BOOL
1960 smtp_verify_helo(void)
1961 {
1962 BOOL yield = TRUE;
1963
1964 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
1965 sender_helo_name);
1966
1967 if (sender_helo_name == NULL)
1968 {
1969 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
1970 }
1971
1972 else if (sender_helo_name[0] == '[')
1973 {
1974 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
1975 Ustrlen(sender_host_address)) == 0;
1976
1977 #if HAVE_IPV6
1978 if (!helo_verified)
1979 {
1980 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
1981 helo_verified = Ustrncmp(sender_helo_name + 1,
1982 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
1983 }
1984 #endif
1985
1986 HDEBUG(D_receive)
1987 { if (helo_verified) debug_printf("matched host address\n"); }
1988 }
1989
1990 /* Do a reverse lookup if one hasn't already given a positive or negative
1991 response. If that fails, or the name doesn't match, try checking with a forward
1992 lookup. */
1993
1994 else
1995 {
1996 if (sender_host_name == NULL && !host_lookup_failed)
1997 yield = host_name_lookup() != DEFER;
1998
1999 /* If a host name is known, check it and all its aliases. */
2000
2001 if (sender_host_name != NULL)
2002 {
2003 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2004
2005 if (helo_verified)
2006 {
2007 HDEBUG(D_receive) debug_printf("matched host name\n");
2008 }
2009 else
2010 {
2011 uschar **aliases = sender_host_aliases;
2012 while (*aliases != NULL)
2013 {
2014 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2015 if (helo_verified) break;
2016 }
2017 HDEBUG(D_receive)
2018 {
2019 if (helo_verified)
2020 debug_printf("matched alias %s\n", *(--aliases));
2021 }
2022 }
2023 }
2024
2025 /* Final attempt: try a forward lookup of the helo name */
2026
2027 if (!helo_verified)
2028 {
2029 int rc;
2030 host_item h;
2031 h.name = sender_helo_name;
2032 h.address = NULL;
2033 h.mx = MX_NONE;
2034 h.next = NULL;
2035 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2036 sender_helo_name);
2037 rc = host_find_byname(&h, NULL, NULL, TRUE);
2038 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2039 {
2040 host_item *hh = &h;
2041 while (hh != NULL)
2042 {
2043 if (Ustrcmp(hh->address, sender_host_address) == 0)
2044 {
2045 helo_verified = TRUE;
2046 HDEBUG(D_receive)
2047 debug_printf("IP address for %s matches calling address\n",
2048 sender_helo_name);
2049 break;
2050 }
2051 hh = hh->next;
2052 }
2053 }
2054 }
2055 }
2056
2057 if (!helo_verified) helo_verify_failed = FALSE; /* We've tried ... */
2058 return yield;
2059 }
2060
2061
2062
2063
2064 /*************************************************
2065 * Initialize for SMTP incoming message *
2066 *************************************************/
2067
2068 /* This function conducts the initial dialogue at the start of an incoming SMTP
2069 message, and builds a list of recipients. However, if the incoming message
2070 is part of a batch (-bS option) a separate function is called since it would
2071 be messy having tests splattered about all over this function. This function
2072 therefore handles the case where interaction is occurring. The input and output
2073 files are set up in smtp_in and smtp_out.
2074
2075 The global recipients_list is set to point to a vector of recipient_item
2076 blocks, whose number is given by recipients_count. This is extended by the
2077 receive_add_recipient() function. The global variable sender_address is set to
2078 the sender's address. The yield is +1 if a message has been successfully
2079 started, 0 if a QUIT command was encountered or the connection was refused from
2080 the particular host, or -1 if the connection was lost.
2081
2082 Argument: none
2083
2084 Returns: > 0 message successfully started (reached DATA)
2085 = 0 QUIT read or end of file reached or call refused
2086 < 0 lost connection
2087 */
2088
2089 int
2090 smtp_setup_msg(void)
2091 {
2092 int done = 0;
2093 BOOL toomany = FALSE;
2094 BOOL discarded = FALSE;
2095 BOOL last_was_rej_mail = FALSE;
2096 BOOL last_was_rcpt = FALSE;
2097 void *reset_point = store_get(0);
2098
2099 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2100
2101 /* Reset for start of new message. We allow one RSET not to be counted as a
2102 nonmail command, for those MTAs that insist on sending it between every
2103 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2104 TLS between messages (an Exim client may do this if it has messages queued up
2105 for the host). Note: we do NOT reset AUTH at this point. */
2106
2107 smtp_reset(reset_point);
2108 message_ended = END_NOTSTARTED;
2109
2110 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2111 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2112 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2113 #ifdef SUPPORT_TLS
2114 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2115 #endif
2116
2117 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2118
2119 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2120
2121 /* Batched SMTP is handled in a different function. */
2122
2123 if (smtp_batched_input) return smtp_setup_batch_msg();
2124
2125 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2126 value. The values are 2 larger than the required yield of the function. */
2127
2128 while (done <= 0)
2129 {
2130 uschar **argv;
2131 uschar *etrn_command;
2132 uschar *etrn_serialize_key;
2133 uschar *errmess;
2134 uschar *user_msg, *log_msg;
2135 uschar *recipient = NULL;
2136 uschar *hello = NULL;
2137 uschar *set_id = NULL;
2138 uschar *s, *ss;
2139 BOOL was_rej_mail = FALSE;
2140 BOOL was_rcpt = FALSE;
2141 void (*oldsignal)(int);
2142 pid_t pid;
2143 int start, end, sender_domain, recipient_domain;
2144 int ptr, size, rc;
2145 int c;
2146 auth_instance *au;
2147
2148 switch(smtp_read_command(TRUE))
2149 {
2150 /* The AUTH command is not permitted to occur inside a transaction, and may
2151 occur successfully only once per connection, and then only when we've
2152 advertised it. Actually, that isn't quite true. When TLS is started, all
2153 previous information about a connection must be discarded, so a new AUTH is
2154 permitted at that time.
2155
2156 AUTH is initially labelled as a "nonmail command" so that one occurrence
2157 doesn't get counted. We change the label here so that multiple failing
2158 AUTHS will eventually hit the nonmail threshold. */
2159
2160 case AUTH_CMD:
2161 authentication_failed = TRUE;
2162 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2163
2164 if (!auth_advertised)
2165 {
2166 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2167 US"AUTH command used when not advertised");
2168 break;
2169 }
2170 if (sender_host_authenticated != NULL)
2171 {
2172 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2173 US"already authenticated");
2174 break;
2175 }
2176 if (sender_address != NULL)
2177 {
2178 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2179 US"not permitted in mail transaction");
2180 break;
2181 }
2182
2183 /* Check the ACL */
2184
2185 if (acl_smtp_auth != NULL)
2186 {
2187 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2188 if (rc != OK)
2189 {
2190 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2191 break;
2192 }
2193 }
2194
2195 /* Find the name of the requested authentication mechanism. */
2196
2197 s = smtp_cmd_argument;
2198 while ((c = *smtp_cmd_argument) != 0 && !isspace(c))
2199 {
2200 if (!isalnum(c) && c != '-' && c != '_')
2201 {
2202 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2203 US"invalid character in authentication mechanism name");
2204 goto COMMAND_LOOP;
2205 }
2206 smtp_cmd_argument++;
2207 }
2208
2209 /* If not at the end of the line, we must be at white space. Terminate the
2210 name and move the pointer on to any data that may be present. */
2211
2212 if (*smtp_cmd_argument != 0)
2213 {
2214 *smtp_cmd_argument++ = 0;
2215 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
2216 }
2217
2218 /* Search for an authentication mechanism which is configured for use
2219 as a server and which has been advertised. */
2220
2221 for (au = auths; au != NULL; au = au->next)
2222 {
2223 if (strcmpic(s, au->public_name) == 0 && au->server &&
2224 au->advertised) break;
2225 }
2226
2227 if (au == NULL)
2228 {
2229 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2230 string_sprintf("%s authentication mechanism not supported", s));
2231 break;
2232 }
2233
2234 /* Run the checking code, passing the remainder of the command
2235 line as data. Initialize $0 empty. The authenticator may set up
2236 other numeric variables. Afterwards, have a go at expanding the set_id
2237 string, even if authentication failed - for bad passwords it can be useful
2238 to log the userid. On success, require set_id to expand and exist, and
2239 put it in authenticated_id. Save this in permanent store, as the working
2240 store gets reset at HELO, RSET, etc. */
2241
2242 expand_nmax = 0;
2243 expand_nlength[0] = 0; /* $0 contains nothing */
2244
2245 c = (au->info->servercode)(au, smtp_cmd_argument);
2246 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2247 expand_nmax = -1; /* Reset numeric variables */
2248
2249 /* The value of authenticated_id is stored in the spool file and printed in
2250 log lines. It must not contain binary zeros or newline characters. In
2251 normal use, it never will, but when playing around or testing, this error
2252 can (did) happen. To guard against this, ensure that the id contains only
2253 printing characters. */
2254
2255 if (set_id != NULL) set_id = string_printing(set_id);
2256
2257 /* For the non-OK cases, set up additional logging data if set_id
2258 is not empty. */
2259
2260 if (c != OK)
2261 {
2262 if (set_id != NULL && *set_id != 0)
2263 set_id = string_sprintf(" (set_id=%s)", set_id);
2264 else set_id = US"";
2265 }
2266
2267 /* Switch on the result */
2268
2269 switch(c)
2270 {
2271 case OK:
2272 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2273 {
2274 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2275 sender_host_authenticated = au->name;
2276 authentication_failed = FALSE;
2277 received_protocol =
2278 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2279 ((sender_host_address != NULL)? pnlocal : 0);
2280 s = ss = US"235 Authentication succeeded";
2281 authenticated_by = au;
2282 break;
2283 }
2284
2285 /* Authentication succeeded, but we failed to expand the set_id string.
2286 Treat this as a temporary error. */
2287
2288 auth_defer_msg = expand_string_message;
2289 /* Fall through */
2290
2291 case DEFER:
2292 s = string_sprintf("435 Unable to authenticate at present%s",
2293 auth_defer_user_msg);
2294 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2295 set_id, auth_defer_msg);
2296 break;
2297
2298 case BAD64:
2299 s = ss = US"501 Invalid base64 data";
2300 break;
2301
2302 case CANCELLED:
2303 s = ss = US"501 Authentication cancelled";
2304 break;
2305
2306 case UNEXPECTED:
2307 s = ss = US"553 Initial data not expected";
2308 break;
2309
2310 case FAIL:
2311 s = US"535 Incorrect authentication data";
2312 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2313 break;
2314
2315 default:
2316 s = US"435 Internal error";
2317 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2318 "check", set_id, c);
2319 break;
2320 }
2321
2322 smtp_printf("%s\r\n", s);
2323 if (c != OK)
2324 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2325 au->name, host_and_ident(FALSE), ss);
2326
2327 break; /* AUTH_CMD */
2328
2329 /* The HELO/EHLO commands are permitted to appear in the middle of a
2330 session as well as at the beginning. They have the effect of a reset in
2331 addition to their other functions. Their absence at the start cannot be
2332 taken to be an error.
2333
2334 RFC 2821 says:
2335
2336 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2337 or 502 failure replies MUST be returned as appropriate. The SMTP
2338 server MUST stay in the same state after transmitting these replies
2339 that it was in before the EHLO was received.
2340
2341 Therefore, we do not do the reset until after checking the command for
2342 acceptability. This change was made for Exim release 4.11. Previously
2343 it did the reset first. */
2344
2345 case HELO_CMD:
2346 hello = US"HELO";
2347 esmtp = FALSE;
2348 goto HELO_EHLO;
2349
2350 case EHLO_CMD:
2351 hello = US"EHLO";
2352 esmtp = TRUE;
2353
2354 HELO_EHLO: /* Common code for HELO and EHLO */
2355 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2356 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2357
2358 /* Reject the HELO if its argument was invalid or non-existent. A
2359 successful check causes the argument to be saved in malloc store. */
2360
2361 if (!check_helo(smtp_cmd_argument))
2362 {
2363 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2364
2365 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2366 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2367 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2368 string_printing(smtp_cmd_argument));
2369
2370 if (++synprot_error_count > smtp_max_synprot_errors)
2371 {
2372 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2373 "syntax or protocol errors (last command was \"%s\")",
2374 host_and_ident(FALSE), smtp_cmd_buffer);
2375 done = 1;
2376 }
2377
2378 break;
2379 }
2380
2381 /* If sender_host_unknown is true, we have got here via the -bs interface,
2382 not called from inetd. Otherwise, we are running an IP connection and the
2383 host address will be set. If the helo name is the primary name of this
2384 host and we haven't done a reverse lookup, force one now. If helo_required
2385 is set, ensure that the HELO name matches the actual host. If helo_verify
2386 is set, do the same check, but softly. */
2387
2388 if (!sender_host_unknown)
2389 {
2390 BOOL old_helo_verified = helo_verified;
2391 uschar *p = smtp_cmd_argument;
2392
2393 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2394 *p = 0;
2395
2396 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2397 because otherwise the log can be confusing. */
2398
2399 if (sender_host_name == NULL &&
2400 (deliver_domain = sender_helo_name, /* set $domain */
2401 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2402 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2403 (void)host_name_lookup();
2404
2405 /* Rebuild the fullhost info to include the HELO name (and the real name
2406 if it was looked up.) */
2407
2408 host_build_sender_fullhost(); /* Rebuild */
2409 set_process_info("handling%s incoming connection from %s",
2410 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2411
2412 /* Verify if configured. This doesn't give much security, but it does
2413 make some people happy to be able to do it. If helo_required is set,
2414 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2415 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2416 now obsolescent, since the verification can now be requested selectively
2417 at ACL time. */
2418
2419 helo_verified = helo_verify_failed = FALSE;
2420 if (helo_required || helo_verify)
2421 {
2422 BOOL tempfail = !smtp_verify_helo();
2423 if (!helo_verified)
2424 {
2425 if (helo_required)
2426 {
2427 smtp_printf("%d %s argument does not match calling host\r\n",
2428 tempfail? 451 : 550, hello);
2429 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2430 tempfail? "temporarily " : "",
2431 hello, sender_helo_name, host_and_ident(FALSE));
2432 helo_verified = old_helo_verified;
2433 break; /* End of HELO/EHLO processing */
2434 }
2435 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2436 "helo_try_verify_hosts\n", hello);
2437 }
2438 }
2439 }
2440
2441 #ifdef EXPERIMENTAL_SPF
2442 /* set up SPF context */
2443 spf_init(sender_helo_name, sender_host_address);
2444 #endif
2445
2446 /* Apply an ACL check if one is defined */
2447
2448 if (acl_smtp_helo != NULL)
2449 {
2450 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2451 if (rc != OK)
2452 {
2453 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2454 sender_helo_name = NULL;
2455 host_build_sender_fullhost(); /* Rebuild */
2456 break;
2457 }
2458 }
2459
2460 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2461 abandoning any previous message. */
2462
2463 received_protocol = (esmtp?
2464 protocols[pextend +
2465 ((sender_host_authenticated != NULL)? pauthed : 0) +
2466 ((tls_active >= 0)? pcrpted : 0)]
2467 :
2468 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2469 +
2470 ((sender_host_address != NULL)? pnlocal : 0);
2471
2472 smtp_reset(reset_point);
2473 toomany = FALSE;
2474
2475 /* Generate an OK reply, including the ident if present, and also
2476 the IP address if present. Reflecting back the ident is intended
2477 as a deterrent to mail forgers. For maximum efficiency, and also
2478 because some broken systems expect each response to be in a single
2479 packet, arrange that it is sent in one write(). */
2480
2481 auth_advertised = FALSE;
2482 pipelining_advertised = FALSE;
2483 #ifdef SUPPORT_TLS
2484 tls_advertised = FALSE;
2485 #endif
2486
2487 s = string_sprintf("250 %s Hello %s%s%s",
2488 smtp_active_hostname,
2489 (sender_ident == NULL)? US"" : sender_ident,
2490 (sender_ident == NULL)? US"" : US" at ",
2491 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2492
2493 ptr = Ustrlen(s);
2494 size = ptr + 1;
2495
2496 if (sender_host_address != NULL)
2497 {
2498 s = string_cat(s, &size, &ptr, US" [", 2);
2499 s = string_cat(s, &size, &ptr, sender_host_address,
2500 Ustrlen(sender_host_address));
2501 s = string_cat(s, &size, &ptr, US"]", 1);
2502 }
2503
2504 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2505
2506 /* If we received EHLO, we must create a multiline response which includes
2507 the functions supported. */
2508
2509 if (esmtp)
2510 {
2511 s[3] = '-';
2512
2513 /* I'm not entirely happy with this, as an MTA is supposed to check
2514 that it has enough room to accept a message of maximum size before
2515 it sends this. However, there seems little point in not sending it.
2516 The actual size check happens later at MAIL FROM time. By postponing it
2517 till then, VRFY and EXPN can be used after EHLO when space is short. */
2518
2519 if (thismessage_size_limit > 0)
2520 {
2521 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2522 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2523 }
2524 else
2525 {
2526 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2527 }
2528
2529 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2530 clean; if it has an 8-bit character in its hand, it just sends it. It
2531 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2532 However, some users want this option simply in order to stop MUAs
2533 mangling messages that contain top-bit-set characters. It is therefore
2534 provided as an option. */
2535
2536 if (accept_8bitmime)
2537 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2538
2539 /* Advertise ETRN if there's an ACL checking whether a host is
2540 permitted to issue it; a check is made when any host actually tries. */
2541
2542 if (acl_smtp_etrn != NULL)
2543 {
2544 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2545 }
2546
2547 /* Advertise EXPN if there's an ACL checking whether a host is
2548 permitted to issue it; a check is made when any host actually tries. */
2549
2550 if (acl_smtp_expn != NULL)
2551 {
2552 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2553 }
2554
2555 /* Exim is quite happy with pipelining, so let the other end know that
2556 it is safe to use it, unless advertising is disabled. */
2557
2558 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2559 {
2560 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2561 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2562 pipelining_advertised = TRUE;
2563 }
2564
2565 /* If any server authentication mechanisms are configured, advertise
2566 them if the current host is in auth_advertise_hosts. The problem with
2567 advertising always is that some clients then require users to
2568 authenticate (and aren't configurable otherwise) even though it may not
2569 be necessary (e.g. if the host is in host_accept_relay).
2570
2571 RFC 2222 states that SASL mechanism names contain only upper case
2572 letters, so output the names in upper case, though we actually recognize
2573 them in either case in the AUTH command. */
2574
2575 if (auths != NULL)
2576 {
2577 if (verify_check_host(&auth_advertise_hosts) == OK)
2578 {
2579 auth_instance *au;
2580 BOOL first = TRUE;
2581 for (au = auths; au != NULL; au = au->next)
2582 {
2583 if (au->server && (au->advertise_condition == NULL ||
2584 expand_check_condition(au->advertise_condition, au->name,
2585 US"authenticator")))
2586 {
2587 int saveptr;
2588 if (first)
2589 {
2590 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2591 first = FALSE;
2592 auth_advertised = TRUE;
2593 }
2594 saveptr = ptr;
2595 s = string_cat(s, &size, &ptr, US" ", 1);
2596 s = string_cat(s, &size, &ptr, au->public_name,
2597 Ustrlen(au->public_name));
2598 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2599 au->advertised = TRUE;
2600 }
2601 else au->advertised = FALSE;
2602 }
2603 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2604 }
2605 }
2606
2607 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2608 if it has been included in the binary, and the host matches
2609 tls_advertise_hosts. We must *not* advertise if we are already in a
2610 secure connection. */
2611
2612 #ifdef SUPPORT_TLS
2613 if (tls_active < 0 &&
2614 verify_check_host(&tls_advertise_hosts) != FAIL)
2615 {
2616 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2617 tls_advertised = TRUE;
2618 }
2619 #endif
2620
2621 /* Finish off the multiline reply with one that is always available. */
2622
2623 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2624 }
2625
2626 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2627 has been seen. */
2628
2629 s[ptr] = 0;
2630
2631 #ifdef SUPPORT_TLS
2632 if (tls_active >= 0) (void)tls_write(s, ptr); else
2633 #endif
2634
2635 (void)fwrite(s, 1, ptr, smtp_out);
2636 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2637 helo_seen = TRUE;
2638 break; /* HELO/EHLO */
2639
2640
2641 /* The MAIL command requires an address as an operand. All we do
2642 here is to parse it for syntactic correctness. The form "<>" is
2643 a special case which converts into an empty string. The start/end
2644 pointers in the original are not used further for this address, as
2645 it is the canonical extracted address which is all that is kept. */
2646
2647 case MAIL_CMD:
2648 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2649 was_rej_mail = TRUE; /* Reset if accepted */
2650
2651 if (helo_required && !helo_seen)
2652 {
2653 smtp_printf("503 HELO or EHLO required\r\n");
2654 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2655 "HELO/EHLO given", host_and_ident(FALSE));
2656 break;
2657 }
2658
2659 if (sender_address != NULL)
2660 {
2661 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2662 US"sender already given");
2663 break;
2664 }
2665
2666 if (smtp_cmd_argument[0] == 0)
2667 {
2668 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2669 US"MAIL must have an address operand");
2670 break;
2671 }
2672
2673 /* Check to see if the limit for messages per connection would be
2674 exceeded by accepting further messages. */
2675
2676 if (smtp_accept_max_per_connection > 0 &&
2677 smtp_mailcmd_count > smtp_accept_max_per_connection)
2678 {
2679 smtp_printf("421 too many messages in this connection\r\n");
2680 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2681 "messages in one connection", host_and_ident(TRUE));
2682 break;
2683 }
2684
2685 /* Reset for start of message - even if this is going to fail, we
2686 obviously need to throw away any previous data. */
2687
2688 smtp_reset(reset_point);
2689 toomany = FALSE;
2690 sender_data = recipient_data = NULL;
2691
2692 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2693
2694 if (esmtp) for(;;)
2695 {
2696 uschar *name, *value, *end;
2697 unsigned long int size;
2698
2699 if (!extract_option(&name, &value)) break;
2700
2701 /* Handle SIZE= by reading the value. We don't do the check till later,
2702 in order to be able to log the sender address on failure. */
2703
2704 if (strcmpic(name, US"SIZE") == 0 &&
2705 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2706 {
2707 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2708 size = INT_MAX;
2709 message_size = (int)size;
2710 }
2711
2712 /* If this session was initiated with EHLO and accept_8bitmime is set,
2713 Exim will have indicated that it supports the BODY=8BITMIME option. In
2714 fact, it does not support this according to the RFCs, in that it does not
2715 take any special action for forwarding messages containing 8-bit
2716 characters. That is why accept_8bitmime is not the default setting, but
2717 some sites want the action that is provided. We recognize both "8BITMIME"
2718 and "7BIT" as body types, but take no action. */
2719
2720 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2721 (strcmpic(value, US"8BITMIME") == 0 ||
2722 strcmpic(value, US"7BIT") == 0)) {}
2723
2724 /* Handle the AUTH extension. If the value given is not "<>" and either
2725 the ACL says "yes" or there is no ACL but the sending host is
2726 authenticated, we set it up as the authenticated sender. However, if the
2727 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2728 the condition is met. The value of AUTH is an xtext, which means that +,
2729 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2730 coding. */
2731
2732 else if (strcmpic(name, US"AUTH") == 0)
2733 {
2734 if (Ustrcmp(value, "<>") != 0)
2735 {
2736 int rc;
2737 uschar *ignore_msg;
2738
2739 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2740 {
2741 /* Put back terminator overrides for error message */
2742 name[-1] = ' ';
2743 value[-1] = '=';
2744 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2745 US"invalid data for AUTH");
2746 goto COMMAND_LOOP;
2747 }
2748
2749 if (acl_smtp_mailauth == NULL)
2750 {
2751 ignore_msg = US"client not authenticated";
2752 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2753 }
2754 else
2755 {
2756 ignore_msg = US"rejected by ACL";
2757 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2758 &user_msg, &log_msg);
2759 }
2760
2761 switch (rc)
2762 {
2763 case OK:
2764 if (authenticated_by == NULL ||
2765 authenticated_by->mail_auth_condition == NULL ||
2766 expand_check_condition(authenticated_by->mail_auth_condition,
2767 authenticated_by->name, US"authenticator"))
2768 break; /* Accept the AUTH */
2769
2770 ignore_msg = US"server_mail_auth_condition failed";
2771 if (authenticated_id != NULL)
2772 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2773 ignore_msg, authenticated_id);
2774
2775 /* Fall through */
2776
2777 case FAIL:
2778 authenticated_sender = NULL;
2779 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2780 value, host_and_ident(TRUE), ignore_msg);
2781 break;
2782
2783 /* Should only get DEFER or ERROR here. Put back terminator
2784 overrides for error message */
2785
2786 default:
2787 name[-1] = ' ';
2788 value[-1] = '=';
2789 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2790 log_msg);
2791 goto COMMAND_LOOP;
2792 }
2793 }
2794 }
2795
2796 /* Unknown option. Stick back the terminator characters and break
2797 the loop. An error for a malformed address will occur. */
2798
2799 else
2800 {
2801 name[-1] = ' ';
2802 value[-1] = '=';
2803 break;
2804 }
2805 }
2806
2807 /* If we have passed the threshold for rate limiting, apply the current
2808 delay, and update it for next time, provided this is a limited host. */
2809
2810 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2811 verify_check_host(&smtp_ratelimit_hosts) == OK)
2812 {
2813 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2814 smtp_delay_mail/1000.0);
2815 millisleep((int)smtp_delay_mail);
2816 smtp_delay_mail *= smtp_rlm_factor;
2817 if (smtp_delay_mail > (double)smtp_rlm_limit)
2818 smtp_delay_mail = (double)smtp_rlm_limit;
2819 }
2820
2821 /* Now extract the address, first applying any SMTP-time rewriting. The
2822 TRUE flag allows "<>" as a sender address. */
2823
2824 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2825 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
2826 global_rewrite_rules) : smtp_cmd_argument;
2827
2828 /* rfc821_domains = TRUE; << no longer needed */
2829 raw_sender =
2830 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2831 TRUE);
2832 /* rfc821_domains = FALSE; << no longer needed */
2833
2834 if (raw_sender == NULL)
2835 {
2836 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
2837 break;
2838 }
2839
2840 sender_address = raw_sender;
2841
2842 /* If there is a configured size limit for mail, check that this message
2843 doesn't exceed it. The check is postponed to this point so that the sender
2844 can be logged. */
2845
2846 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2847 {
2848 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2849 log_write(L_size_reject,
2850 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2851 "message too big: size%s=%d max=%d",
2852 sender_address,
2853 host_and_ident(TRUE),
2854 (message_size == INT_MAX)? ">" : "",
2855 message_size,
2856 thismessage_size_limit);
2857 sender_address = NULL;
2858 break;
2859 }
2860
2861 /* Check there is enough space on the disk unless configured not to.
2862 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2863 plus the current message - i.e. we accept the message only if it won't
2864 reduce the space below the threshold. Add 5000 to the size to allow for
2865 overheads such as the Received: line and storing of recipients, etc.
2866 By putting the check here, even when SIZE is not given, it allow VRFY
2867 and EXPN etc. to be used when space is short. */
2868
2869 if (!receive_check_fs(
2870 (smtp_check_spool_space && message_size >= 0)?
2871 message_size + 5000 : 0))
2872 {
2873 smtp_printf("452 Space shortage, please try later\r\n");
2874 sender_address = NULL;
2875 break;
2876 }
2877
2878 /* If sender_address is unqualified, reject it, unless this is a locally
2879 generated message, or the sending host or net is permitted to send
2880 unqualified addresses - typically local machines behaving as MUAs -
2881 in which case just qualify the address. The flag is set above at the start
2882 of the SMTP connection. */
2883
2884 if (sender_domain == 0 && sender_address[0] != 0)
2885 {
2886 if (allow_unqualified_sender)
2887 {
2888 sender_domain = Ustrlen(sender_address) + 1;
2889 sender_address = rewrite_address_qualify(sender_address, FALSE);
2890 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2891 raw_sender);
2892 }
2893 else
2894 {
2895 smtp_printf("501 %s: sender address must contain a domain\r\n",
2896 smtp_cmd_argument);
2897 log_write(L_smtp_syntax_error,
2898 LOG_MAIN|LOG_REJECT,
2899 "unqualified sender rejected: <%s> %s%s",
2900 raw_sender,
2901 host_and_ident(TRUE),
2902 host_lookup_msg);
2903 sender_address = NULL;
2904 break;
2905 }
2906 }
2907
2908 /* Apply an ACL check if one is defined, before responding */
2909
2910 rc = (acl_smtp_mail == NULL)? OK :
2911 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2912
2913 if (rc == OK || rc == DISCARD)
2914 {
2915 smtp_printf("250 OK\r\n");
2916 smtp_delay_rcpt = smtp_rlr_base;
2917 recipients_discarded = (rc == DISCARD);
2918 was_rej_mail = FALSE;
2919 }
2920
2921 else
2922 {
2923 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2924 sender_address = NULL;
2925 }
2926 break;
2927
2928
2929 /* The RCPT command requires an address as an operand. All we do
2930 here is to parse it for syntactic correctness. There may be any number
2931 of RCPT commands, specifying multiple senders. We build them all into
2932 a data structure that is in argc/argv format. The start/end values
2933 given by parse_extract_address are not used, as we keep only the
2934 extracted address. */
2935
2936 case RCPT_CMD:
2937 rcpt_count++;
2938 was_rcpt = TRUE;
2939
2940 /* There must be a sender address; if the sender was rejected and
2941 pipelining was advertised, we assume the client was pipelining, and do not
2942 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2943 get the same treatment. */
2944
2945 if (sender_address == NULL)
2946 {
2947 if (pipelining_advertised && last_was_rej_mail)
2948 {
2949 smtp_printf("503 sender not yet given\r\n");
2950 was_rej_mail = TRUE;
2951 }
2952 else
2953 {
2954 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2955 US"sender not yet given");
2956 was_rcpt = FALSE; /* Not a valid RCPT */
2957 }
2958 rcpt_fail_count++;
2959 break;
2960 }
2961
2962 /* Check for an operand */
2963
2964 if (smtp_cmd_argument[0] == 0)
2965 {
2966 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2967 US"RCPT must have an address operand");
2968 rcpt_fail_count++;
2969 break;
2970 }
2971
2972 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2973 as a recipient address */
2974
2975 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2976 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
2977 global_rewrite_rules) : smtp_cmd_argument;
2978
2979 /* rfc821_domains = TRUE; << no longer needed */
2980 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2981 &recipient_domain, FALSE);
2982 /* rfc821_domains = FALSE; << no longer needed */
2983
2984 if (recipient == NULL)
2985 {
2986 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
2987 rcpt_fail_count++;
2988 break;
2989 }
2990
2991 /* If the recipient address is unqualified, reject it, unless this is a
2992 locally generated message. However, unqualified addresses are permitted
2993 from a configured list of hosts and nets - typically when behaving as
2994 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2995 really. The flag is set at the start of the SMTP connection.
2996
2997 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2998 assumed this meant "reserved local part", but the revision of RFC 821 and
2999 friends now makes it absolutely clear that it means *mailbox*. Consequently
3000 we must always qualify this address, regardless. */
3001
3002 if (recipient_domain == 0)
3003 {
3004 if (allow_unqualified_recipient ||
3005 strcmpic(recipient, US"postmaster") == 0)
3006 {
3007 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3008 recipient);
3009 recipient_domain = Ustrlen(recipient) + 1;
3010 recipient = rewrite_address_qualify(recipient, TRUE);
3011 }
3012 else
3013 {
3014 rcpt_fail_count++;
3015 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3016 smtp_cmd_argument);
3017 log_write(L_smtp_syntax_error,
3018 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3019 "<%s> %s%s", recipient, host_and_ident(TRUE),
3020 host_lookup_msg);
3021 break;
3022 }
3023 }
3024
3025 /* Check maximum allowed */
3026
3027 if (rcpt_count > recipients_max && recipients_max > 0)
3028 {
3029 if (recipients_max_reject)
3030 {
3031 rcpt_fail_count++;
3032 smtp_printf("552 too many recipients\r\n");
3033 if (!toomany)
3034 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3035 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3036 }
3037 else
3038 {
3039 rcpt_defer_count++;
3040 smtp_printf("452 too many recipients\r\n");
3041 if (!toomany)
3042 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3043 "temporarily rejected: sender=<%s> %s", sender_address,
3044 host_and_ident(TRUE));
3045 }
3046
3047 toomany = TRUE;
3048 break;
3049 }
3050
3051 /* If we have passed the threshold for rate limiting, apply the current
3052 delay, and update it for next time, provided this is a limited host. */
3053
3054 if (rcpt_count > smtp_rlr_threshold &&
3055 verify_check_host(&smtp_ratelimit_hosts) == OK)
3056 {
3057 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3058 smtp_delay_rcpt/1000.0);
3059 millisleep((int)smtp_delay_rcpt);
3060 smtp_delay_rcpt *= smtp_rlr_factor;
3061 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3062 smtp_delay_rcpt = (double)smtp_rlr_limit;
3063 }
3064
3065 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3066 for them. Otherwise, check the access control list for this recipient. */
3067
3068 rc = recipients_discarded? DISCARD :
3069 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3070
3071 /* The ACL was happy */
3072
3073 if (rc == OK)
3074 {
3075 smtp_printf("250 Accepted\r\n");
3076 receive_add_recipient(recipient, -1);
3077 }
3078
3079 /* The recipient was discarded */
3080
3081 else if (rc == DISCARD)
3082 {
3083 smtp_printf("250 Accepted\r\n");
3084 rcpt_fail_count++;
3085 discarded = TRUE;
3086 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3087 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3088 (sender_address_unrewritten != NULL)?
3089 sender_address_unrewritten : sender_address,
3090 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3091 (log_msg == NULL)? US"" : US": ",
3092 (log_msg == NULL)? US"" : log_msg);
3093 }
3094
3095 /* Either the ACL failed the address, or it was deferred. */
3096
3097 else
3098 {
3099 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3100 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3101 }
3102 break;
3103
3104
3105 /* The DATA command is legal only if it follows successful MAIL FROM
3106 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3107 not counted as a protocol error if it follows RCPT (which must have been
3108 rejected if there are no recipients.) This function is complete when a
3109 valid DATA command is encountered.
3110
3111 Note concerning the code used: RFC 2821 says this:
3112
3113 - If there was no MAIL, or no RCPT, command, or all such commands
3114 were rejected, the server MAY return a "command out of sequence"
3115 (503) or "no valid recipients" (554) reply in response to the
3116 DATA command.
3117
3118 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3119 because it is the same whether pipelining is in use or not. */
3120
3121 case DATA_CMD:
3122 if (!discarded && recipients_count <= 0)
3123 {
3124 if (pipelining_advertised && last_was_rcpt)
3125 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3126 else
3127 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3128 US"valid RCPT command must precede DATA");
3129 break;
3130 }
3131
3132 if (toomany && recipients_max_reject)
3133 {
3134 sender_address = NULL; /* This will allow a new MAIL without RSET */
3135 sender_address_unrewritten = NULL;
3136 smtp_printf("554 Too many recipients\r\n");
3137 break;
3138 }
3139
3140 if (acl_smtp_predata == NULL) rc = OK; else
3141 {
3142 enable_dollar_recipients = TRUE;
3143 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3144 &log_msg);
3145 enable_dollar_recipients = FALSE;
3146 }
3147
3148 if (rc == OK)
3149 {
3150 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3151 done = 3;
3152 message_ended = END_NOTENDED; /* Indicate in middle of data */
3153 }
3154
3155 /* Either the ACL failed the address, or it was deferred. */
3156
3157 else
3158 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3159
3160 break;
3161
3162
3163 case VRFY_CMD:
3164 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3165 if (rc != OK)
3166 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3167 else
3168 {
3169 uschar *address;
3170 uschar *s = NULL;
3171
3172 /* rfc821_domains = TRUE; << no longer needed */
3173 address = parse_extract_address(smtp_cmd_argument, &errmess, &start, &end,
3174 &recipient_domain, FALSE);
3175 /* rfc821_domains = FALSE; << no longer needed */
3176
3177 if (address == NULL)
3178 s = string_sprintf("501 %s", errmess);
3179 else
3180 {
3181 address_item *addr = deliver_make_addr(address, FALSE);
3182 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3183 -1, -1, NULL, NULL, NULL))
3184 {
3185 case OK:
3186 s = string_sprintf("250 <%s> is deliverable", address);
3187 break;
3188
3189 case DEFER:
3190 s = (addr->message != NULL)?
3191 string_sprintf("451 <%s> %s", address, addr->message) :
3192 string_sprintf("451 Cannot resolve <%s> at this time", address);
3193 break;
3194
3195 case FAIL:
3196 s = (addr->message != NULL)?
3197 string_sprintf("550 <%s> %s", address, addr->message) :
3198 string_sprintf("550 <%s> is not deliverable", address);
3199 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3200 smtp_cmd_argument, host_and_ident(TRUE));
3201 break;
3202 }
3203 }
3204
3205 smtp_printf("%s\r\n", s);
3206 }
3207 break;
3208
3209
3210 case EXPN_CMD:
3211 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3212 if (rc != OK)
3213 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3214 else
3215 {
3216 BOOL save_log_testing_mode = log_testing_mode;
3217 address_test_mode = log_testing_mode = TRUE;
3218 (void) verify_address(deliver_make_addr(smtp_cmd_argument, FALSE),
3219 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3220 NULL, NULL, NULL);
3221 address_test_mode = FALSE;
3222 log_testing_mode = save_log_testing_mode; /* true for -bh */
3223 }
3224 break;
3225
3226
3227 #ifdef SUPPORT_TLS
3228
3229 case STARTTLS_CMD:
3230 if (!tls_advertised)
3231 {
3232 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3233 US"STARTTLS command used when not advertised");
3234 break;
3235 }
3236
3237 /* Apply an ACL check if one is defined */
3238
3239 if (acl_smtp_starttls != NULL)
3240 {
3241 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3242 &log_msg);
3243 if (rc != OK)
3244 {
3245 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3246 break;
3247 }
3248 }
3249
3250 /* RFC 2487 is not clear on when this command may be sent, though it
3251 does state that all information previously obtained from the client
3252 must be discarded if a TLS session is started. It seems reasonble to
3253 do an implied RSET when STARTTLS is received. */
3254
3255 incomplete_transaction_log(US"STARTTLS");
3256 smtp_reset(reset_point);
3257 toomany = FALSE;
3258 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3259
3260 /* Attempt to start up a TLS session, and if successful, discard all
3261 knowledge that was obtained previously. At least, that's what the RFC says,
3262 and that's what happens by default. However, in order to work round YAEB,
3263 there is an option to remember the esmtp state. Sigh.
3264
3265 We must allow for an extra EHLO command and an extra AUTH command after
3266 STARTTLS that don't add to the nonmail command count. */
3267
3268 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3269 {
3270 if (!tls_remember_esmtp)
3271 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3272 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3273 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3274 if (sender_helo_name != NULL)
3275 {
3276 store_free(sender_helo_name);
3277 sender_helo_name = NULL;
3278 host_build_sender_fullhost(); /* Rebuild */
3279 set_process_info("handling incoming TLS connection from %s",
3280 host_and_ident(FALSE));
3281 }
3282 received_protocol = (esmtp?
3283 protocols[pextend + pcrpted +
3284 ((sender_host_authenticated != NULL)? pauthed : 0)]
3285 :
3286 protocols[pnormal + pcrpted])
3287 +
3288 ((sender_host_address != NULL)? pnlocal : 0);
3289
3290 sender_host_authenticated = NULL;
3291 authenticated_id = NULL;
3292 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3293 DEBUG(D_tls) debug_printf("TLS active\n");
3294 break; /* Successful STARTTLS */
3295 }
3296
3297 /* Some local configuration problem was discovered before actually trying
3298 to do a TLS handshake; give a temporary error. */
3299
3300 else if (rc == DEFER)
3301 {
3302 smtp_printf("454 TLS currently unavailable\r\n");
3303 break;
3304 }
3305
3306 /* Hard failure. Reject everything except QUIT or closed connection. One
3307 cause for failure is a nested STARTTLS, in which case tls_active remains
3308 set, but we must still reject all incoming commands. */
3309
3310 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3311 while (done <= 0)
3312 {
3313 switch(smtp_read_command(FALSE))
3314 {
3315 case EOF_CMD:
3316 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3317 smtp_get_connection_info());
3318 done = 2;
3319 break;
3320
3321 case QUIT_CMD:
3322 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3323 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3324 smtp_get_connection_info());
3325 done = 2;
3326 break;
3327
3328 default:
3329 smtp_printf("554 Security failure\r\n");
3330 break;
3331 }
3332 }
3333 tls_close(TRUE);
3334 break;
3335 #endif
3336
3337
3338 /* The ACL for QUIT is provided for gathering statistical information or
3339 similar; it does not affect the response code, but it can supply a custom
3340 message. */
3341
3342 case QUIT_CMD:
3343 incomplete_transaction_log(US"QUIT");
3344
3345 if (acl_smtp_quit != NULL)
3346 {
3347 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit,&user_msg,&log_msg);
3348 if (rc == ERROR)
3349 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3350 log_msg);
3351 }
3352 else user_msg = NULL;
3353
3354 if (user_msg == NULL)
3355 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3356 else
3357 smtp_printf("221 %s\r\n", user_msg);
3358
3359 #ifdef SUPPORT_TLS
3360 tls_close(TRUE);
3361 #endif
3362
3363 done = 2;
3364 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3365 smtp_get_connection_info());
3366 break;
3367
3368
3369 case RSET_CMD:
3370 incomplete_transaction_log(US"RSET");
3371 smtp_reset(reset_point);
3372 toomany = FALSE;
3373 smtp_printf("250 Reset OK\r\n");
3374 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3375 break;
3376
3377
3378 case NOOP_CMD:
3379 smtp_printf("250 OK\r\n");
3380 break;
3381
3382
3383 /* Show ETRN/EXPN/VRFY if there's
3384 an ACL for checking hosts; if actually used, a check will be done for
3385 permitted hosts. */
3386
3387 case HELP_CMD:
3388 smtp_printf("214-Commands supported:\r\n");
3389 {
3390 uschar buffer[256];
3391 buffer[0] = 0;
3392 Ustrcat(buffer, " AUTH");
3393 #ifdef SUPPORT_TLS
3394 Ustrcat(buffer, " STARTTLS");
3395 #endif
3396 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3397 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3398 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3399 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3400 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3401 smtp_printf("214%s\r\n", buffer);
3402 }
3403 break;
3404
3405
3406 case EOF_CMD:
3407 incomplete_transaction_log(US"connection lost");
3408 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3409
3410 /* Don't log by default unless in the middle of a message, as some mailers
3411 just drop the call rather than sending QUIT, and it clutters up the logs.
3412 */
3413
3414 if (sender_address != NULL || recipients_count > 0)
3415 log_write(L_lost_incoming_connection,
3416 LOG_MAIN,
3417 "unexpected %s while reading SMTP command from %s%s",
3418 sender_host_unknown? "EOF" : "disconnection",
3419 host_and_ident(FALSE), smtp_read_error);
3420
3421 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3422 smtp_get_connection_info(), smtp_read_error);
3423
3424 done = 1;
3425 break;
3426
3427
3428 case ETRN_CMD:
3429 if (sender_address != NULL)
3430 {
3431 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3432 US"ETRN is not permitted inside a transaction");
3433 break;
3434 }
3435
3436 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
3437 host_and_ident(FALSE));
3438
3439 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
3440 if (rc != OK)
3441 {
3442 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3443 break;
3444 }
3445
3446 /* Compute the serialization key for this command. */
3447
3448 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_argument);
3449
3450 /* If a command has been specified for running as a result of ETRN, we
3451 permit any argument to ETRN. If not, only the # standard form is permitted,
3452 since that is strictly the only kind of ETRN that can be implemented
3453 according to the RFC. */
3454
3455 if (smtp_etrn_command != NULL)
3456 {
3457 uschar *error;
3458 BOOL rc;
3459 etrn_command = smtp_etrn_command;
3460 deliver_domain = smtp_cmd_argument;
3461 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3462 US"ETRN processing", &error);
3463 deliver_domain = NULL;
3464 if (!rc)
3465 {
3466 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3467 error);
3468 smtp_printf("458 Internal failure\r\n");
3469 break;
3470 }
3471 }
3472
3473 /* Else set up to call Exim with the -R option. */
3474
3475 else
3476 {
3477 if (*smtp_cmd_argument++ != '#')
3478 {
3479 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3480 US"argument must begin with #");
3481 break;
3482 }
3483 etrn_command = US"exim -R";
3484 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3485 smtp_cmd_argument);
3486 }
3487
3488 /* If we are host-testing, don't actually do anything. */
3489
3490 if (host_checking)
3491 {
3492 HDEBUG(D_any)
3493 {
3494 debug_printf("ETRN command is: %s\n", etrn_command);
3495 debug_printf("ETRN command execution skipped\n");
3496 }
3497 smtp_printf("250 OK\r\n");
3498 break;
3499 }
3500
3501
3502 /* If ETRN queue runs are to be serialized, check the database to
3503 ensure one isn't already running. */
3504
3505 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3506 {
3507 smtp_printf("458 Already processing %s\r\n", smtp_cmd_argument);
3508 break;
3509 }
3510
3511 /* Fork a child process and run the command. We don't want to have to
3512 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3513 forking. It should be set that way anyway for external incoming SMTP,
3514 but we save and restore to be tidy. If serialization is required, we
3515 actually run the command in yet another process, so we can wait for it
3516 to complete and then remove the serialization lock. */
3517
3518 oldsignal = signal(SIGCHLD, SIG_IGN);
3519
3520 if ((pid = fork()) == 0)
3521 {
3522 smtp_input = FALSE; /* This process is not associated with the */
3523 (void)fclose(smtp_in); /* SMTP call any more. */
3524 (void)fclose(smtp_out);
3525
3526 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3527
3528 /* If not serializing, do the exec right away. Otherwise, fork down
3529 into another process. */
3530
3531 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3532 {
3533 DEBUG(D_exec) debug_print_argv(argv);
3534 exim_nullstd(); /* Ensure std{in,out,err} exist */
3535 execv(CS argv[0], (char *const *)argv);
3536 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3537 etrn_command, strerror(errno));
3538 _exit(EXIT_FAILURE); /* paranoia */
3539 }
3540
3541 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3542 is, we are in the first subprocess, after forking again. All we can do
3543 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3544 complete, before removing the serialization. */
3545
3546 if (pid < 0)
3547 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3548 "failed: %s", strerror(errno));
3549 else
3550 {
3551 int status;
3552 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3553 (int)pid);
3554 (void)wait(&status);
3555 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3556 (int)pid);
3557 }
3558
3559 enq_end(etrn_serialize_key);
3560 _exit(EXIT_SUCCESS);
3561 }
3562
3563 /* Back in the top level SMTP process. Check that we started a subprocess
3564 and restore the signal state. */
3565
3566 if (pid < 0)
3567 {
3568 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3569 strerror(errno));
3570 smtp_printf("458 Unable to fork process\r\n");
3571 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3572 }
3573 else smtp_printf("250 OK\r\n");
3574
3575 signal(SIGCHLD, oldsignal);
3576 break;
3577
3578
3579 case BADARG_CMD:
3580 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3581 US"unexpected argument data");
3582 break;
3583
3584
3585 /* This currently happens only for NULLs, but could be extended. */
3586
3587 case BADCHAR_CMD:
3588 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3589 US"NULL character(s) present (shown as '?')");
3590 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3591 break;
3592
3593
3594 case BADSYN_CMD:
3595 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3596 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3597 c = smtp_inend - smtp_inptr;
3598 if (c > 150) c = 150;
3599 smtp_inptr[c] = 0;
3600 incomplete_transaction_log(US"sync failure");
3601 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
3602 "(next input sent too soon: pipelining was%s advertised): "
3603 "rejected \"%s\" %s next input=\"%s\"",
3604 pipelining_advertised? "" : " not",
3605 smtp_cmd_buffer, host_and_ident(TRUE),
3606 string_printing(smtp_inptr));
3607 smtp_printf("554 SMTP synchronization error\r\n");
3608 done = 1; /* Pretend eof - drops connection */
3609 break;
3610
3611
3612 case TOO_MANY_NONMAIL_CMD:
3613 incomplete_transaction_log(US"too many non-mail commands");
3614 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3615 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
3616 smtp_cmd_argument - smtp_cmd_buffer, smtp_cmd_buffer);
3617 smtp_printf("554 Too many nonmail commands\r\n");
3618 done = 1; /* Pretend eof - drops connection */
3619 break;
3620
3621
3622 default:
3623 if (unknown_command_count++ >= smtp_max_unknown_commands)
3624 {
3625 log_write(L_smtp_syntax_error, LOG_MAIN,
3626 "SMTP syntax error in \"%s\" %s %s",
3627 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
3628 US"unrecognized command");
3629 incomplete_transaction_log(US"unrecognized command");
3630 smtp_printf("500 Too many unrecognized commands\r\n");
3631 done = 2;
3632 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3633 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3634 smtp_cmd_buffer);
3635 }
3636 else
3637 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3638 US"unrecognized command");
3639 break;
3640 }
3641
3642 /* This label is used by goto's inside loops that want to break out to
3643 the end of the command-processing loop. */
3644
3645 COMMAND_LOOP:
3646 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3647 last_was_rcpt = was_rcpt; /* protocol error handling */
3648 continue;
3649 }
3650
3651 return done - 2; /* Convert yield values */
3652 }
3653
3654 /* End of smtp_in.c */