Merge from EXISCAN branch.
[exim.git] / src / src / smtp_in.c
1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.6 2004/12/16 15:11:47 tom Exp $ */
2
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
6
7 /* Copyright (c) University of Cambridge 1995 - 2004 */
8 /* See the file NOTICE for conditions of use and distribution. */
9
10 /* Functions for handling an incoming SMTP call. */
11
12
13 #include "exim.h"
14
15
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
19
20 #ifdef USE_TCP_WRAPPERS
21
22 #if HAVE_IPV6
23 #define EXIM_HAVE_IPV6
24 #endif
25 #undef HAVE_IPV6
26 #include <tcpd.h>
27 #undef HAVE_IPV6
28 #ifdef EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
30 #endif
31
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
34 #endif
35
36
37 /* Size of buffer for reading SMTP commands */
38
39 #define cmd_buffer_size 512 /* Ref. RFC 821 */
40
41 /* Size of buffer for reading SMTP incoming packets */
42
43 #define in_buffer_size 8192
44
45 /* Structure for SMTP command list */
46
47 typedef struct {
48 char *name;
49 int len;
50 short int cmd;
51 short int has_arg;
52 short int is_mail_cmd;
53 } smtp_cmd_list;
54
55 /* Codes for identifying commands. We order them so that those that come first
56 are those for which synchronization is always required. Checking this can help
57 block some spam. */
58
59 enum {
60 /* These commands are required to be synchronized, i.e. to be the last in a
61 block of commands when pipelining. */
62
63 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
64 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
65 ETRN_CMD, /* This by analogy with TURN from the RFC */
66 STARTTLS_CMD, /* Required by the STARTTLS RFC */
67
68 /* This is a dummy to identify the non-sync commands when pipelining */
69
70 NON_SYNC_CMD_PIPELINING,
71
72 /* These commands need not be synchronized when pipelining */
73
74 MAIL_CMD, RCPT_CMD, RSET_CMD,
75
76 /* This is a dummy to identify the non-sync commands when not pipelining */
77
78 NON_SYNC_CMD_NON_PIPELINING,
79
80 /* I have been unable to find a statement about the use of pipelining
81 with AUTH, so to be on the safe side it is here, though I kind of feel
82 it should be up there with the synchronized commands. */
83
84 AUTH_CMD,
85
86 /* I'm not sure about these, but I don't think they matter. */
87
88 QUIT_CMD, HELP_CMD,
89
90 /* These are specials that don't correspond to actual commands */
91
92 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
93 TOO_MANY_NONMAIL_CMD };
94
95
96
97 /*************************************************
98 * Local static variables *
99 *************************************************/
100
101 static auth_instance *authenticated_by;
102 static BOOL auth_advertised;
103 #ifdef SUPPORT_TLS
104 static BOOL tls_advertised;
105 #endif
106 static BOOL esmtp;
107 static BOOL helo_required = FALSE;
108 static BOOL helo_verify = FALSE;
109 static BOOL helo_seen;
110 static BOOL helo_accept_junk;
111 static BOOL count_nonmail;
112 static BOOL pipelining_advertised;
113 static int nonmail_command_count;
114 static int synprot_error_count;
115 static int unknown_command_count;
116 static int sync_cmd_limit;
117 static int smtp_write_error = 0;
118
119 static uschar *smtp_data;
120
121 static uschar *cmd_buffer;
122
123 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
124 final fields of all except AUTH are forced TRUE at the start of a new message
125 setup, to allow one of each between messages that is not counted as a nonmail
126 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
127 allow a new EHLO after starting up TLS.
128
129 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
130 counted. However, the flag is changed when AUTH is received, so that multiple
131 failing AUTHs will eventually hit the limit. After a successful AUTH, another
132 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
133 forced TRUE, to allow for the re-authentication that can happen at that point.
134
135 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
136 count of non-mail commands and possibly provoke an error. */
137
138 static smtp_cmd_list cmd_list[] = {
139 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
140 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
141 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
142 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
143 #ifdef SUPPORT_TLS
144 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
145 #endif
146
147 /* If you change anything above here, also fix the definitions below. */
148
149 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
150 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
151 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
152 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
153 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
154 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
155 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
156 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
157 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
158 };
159
160 static smtp_cmd_list *cmd_list_end =
161 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
162
163 #define CMD_LIST_RSET 0
164 #define CMD_LIST_HELO 1
165 #define CMD_LIST_EHLO 2
166 #define CMD_LIST_AUTH 3
167 #define CMD_LIST_STARTTLS 4
168
169 static uschar *protocols[] = {
170 US"local-smtp", /* HELO */
171 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
172 US"local-esmtp", /* EHLO */
173 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
174 US"local-esmtpa", /* EHLO->AUTH */
175 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
176 };
177
178 #define pnormal 0
179 #define pextend 2
180 #define pcrpted 1 /* added to pextend or pnormal */
181 #define pauthed 2 /* added to pextend */
182 #define pnlocal 6 /* offset to remove "local" */
183
184 /* When reading SMTP from a remote host, we have to use our own versions of the
185 C input-reading functions, in order to be able to flush the SMTP output only
186 when about to read more data from the socket. This is the only way to get
187 optimal performance when the client is using pipelining. Flushing for every
188 command causes a separate packet and reply packet each time; saving all the
189 responses up (when pipelining) combines them into one packet and one response.
190
191 For simplicity, these functions are used for *all* SMTP input, not only when
192 receiving over a socket. However, after setting up a secure socket (SSL), input
193 is read via the OpenSSL library, and another set of functions is used instead
194 (see tls.c).
195
196 These functions are set in the receive_getc etc. variables and called with the
197 same interface as the C functions. However, since there can only ever be
198 one incoming SMTP call, we just use a single buffer and flags. There is no need
199 to implement a complicated private FILE-like structure.*/
200
201 static uschar *smtp_inbuffer;
202 static uschar *smtp_inptr;
203 static uschar *smtp_inend;
204 static int smtp_had_eof;
205 static int smtp_had_error;
206
207
208 /*************************************************
209 * SMTP version of getc() *
210 *************************************************/
211
212 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
213 it flushes the output, and refills the buffer, with a timeout. The signal
214 handler is set appropriately by the calling function. This function is not used
215 after a connection has negotated itself into an TLS/SSL state.
216
217 Arguments: none
218 Returns: the next character or EOF
219 */
220
221 int
222 smtp_getc(void)
223 {
224 if (smtp_inptr >= smtp_inend)
225 {
226 int rc, save_errno;
227 fflush(smtp_out);
228 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
229 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
230 save_errno = errno;
231 alarm(0);
232 if (rc <= 0)
233 {
234 /* Must put the error text in fixed store, because this might be during
235 header reading, where it releases unused store above the header. */
236 if (rc < 0)
237 {
238 smtp_had_error = save_errno;
239 smtp_read_error = string_copy_malloc(
240 string_sprintf(" (error: %s)", strerror(save_errno)));
241 }
242 else smtp_had_eof = 1;
243 return EOF;
244 }
245 smtp_inend = smtp_inbuffer + rc;
246 smtp_inptr = smtp_inbuffer;
247 }
248 return *smtp_inptr++;
249 }
250
251
252
253 /*************************************************
254 * SMTP version of ungetc() *
255 *************************************************/
256
257 /* Puts a character back in the input buffer. Only ever
258 called once.
259
260 Arguments:
261 ch the character
262
263 Returns: the character
264 */
265
266 int
267 smtp_ungetc(int ch)
268 {
269 *(--smtp_inptr) = ch;
270 return ch;
271 }
272
273
274
275
276 /*************************************************
277 * SMTP version of feof() *
278 *************************************************/
279
280 /* Tests for a previous EOF
281
282 Arguments: none
283 Returns: non-zero if the eof flag is set
284 */
285
286 int
287 smtp_feof(void)
288 {
289 return smtp_had_eof;
290 }
291
292
293
294
295 /*************************************************
296 * SMTP version of ferror() *
297 *************************************************/
298
299 /* Tests for a previous read error, and returns with errno
300 restored to what it was when the error was detected.
301
302 Arguments: none
303 Returns: non-zero if the error flag is set
304 */
305
306 int
307 smtp_ferror(void)
308 {
309 errno = smtp_had_error;
310 return smtp_had_error;
311 }
312
313
314
315
316 /*************************************************
317 * Write formatted string to SMTP channel *
318 *************************************************/
319
320 /* This is a separate function so that we don't have to repeat everything for
321 TLS support or debugging. It is global so that the daemon and the
322 authentication functions can use it. It does not return any error indication,
323 because major problems such as dropped connections won't show up till an output
324 flush for non-TLS connections. The smtp_fflush() function is available for
325 checking that: for convenience, TLS output errors are remembered here so that
326 they are also picked up later by smtp_fflush().
327
328 Arguments:
329 format format string
330 ... optional arguments
331
332 Returns: nothing
333 */
334
335 void
336 smtp_printf(char *format, ...)
337 {
338 va_list ap;
339
340 DEBUG(D_receive)
341 {
342 va_start(ap, format);
343 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
344 debug_printf("SMTP>> %s", big_buffer);
345 }
346
347 va_start(ap, format);
348
349 /* If in a TLS session we have to format the string, and then write it using a
350 TLS function. */
351
352 #ifdef SUPPORT_TLS
353 if (tls_active >= 0)
354 {
355 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
356 {
357 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
358 smtp_closedown(US"Unexpected error");
359 exim_exit(EXIT_FAILURE);
360 }
361 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
362 }
363 else
364 #endif
365
366 /* Otherwise, just use the standard library function. */
367
368 if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
369 va_end(ap);
370 }
371
372
373
374 /*************************************************
375 * Flush SMTP out and check for error *
376 *************************************************/
377
378 /* This function isn't currently used within Exim (it detects errors when it
379 tries to read the next SMTP input), but is available for use in local_scan().
380 For non-TLS connections, it flushes the output and checks for errors. For
381 TLS-connections, it checks for a previously-detected TLS write error.
382
383 Arguments: none
384 Returns: 0 for no error; -1 after an error
385 */
386
387 int
388 smtp_fflush(void)
389 {
390 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
391 return smtp_write_error;
392 }
393
394
395
396 /*************************************************
397 * SMTP command read timeout *
398 *************************************************/
399
400 /* Signal handler for timing out incoming SMTP commands. This attempts to
401 finish off tidily.
402
403 Argument: signal number (SIGALRM)
404 Returns: nothing
405 */
406
407 static void
408 command_timeout_handler(int sig)
409 {
410 sig = sig; /* Keep picky compilers happy */
411 log_write(L_lost_incoming_connection,
412 LOG_MAIN, "SMTP command timeout on%s connection from %s",
413 (tls_active >= 0)? " TLS" : "",
414 host_and_ident(FALSE));
415 if (smtp_batched_input)
416 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
417 smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
418 smtp_active_hostname);
419 mac_smtp_fflush();
420 exim_exit(EXIT_FAILURE);
421 }
422
423
424
425 /*************************************************
426 * SIGTERM received *
427 *************************************************/
428
429 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
430
431 Argument: signal number (SIGTERM)
432 Returns: nothing
433 */
434
435 static void
436 command_sigterm_handler(int sig)
437 {
438 sig = sig; /* Keep picky compilers happy */
439 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
440 if (smtp_batched_input)
441 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
442 smtp_printf("421 %s: Service not available - closing connection\r\n",
443 smtp_active_hostname);
444 exim_exit(EXIT_FAILURE);
445 }
446
447
448
449 /*************************************************
450 * Read one command line *
451 *************************************************/
452
453 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
454 There are sites that don't do this, and in any case internal SMTP probably
455 should check only for LF. Consequently, we check here for LF only. The line
456 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
457 an unknown command. The command is read into the static cmd_buffer.
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 >= 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 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(cmd_buffer[ptr-1])) ptr--;
507 cmd_buffer[ptr] = 0;
508
509 DEBUG(D_receive) debug_printf("SMTP<< %s\n", 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(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_data = 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 no data
554 for a command that expects it, we give the error centrally here. */
555
556 while (isspace(*smtp_data)) smtp_data++;
557 return (p->has_arg || *smtp_data == 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_data. 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_data + Ustrlen(smtp_data) -1;
761 while (isspace(*v)) v--;
762 v[1] = 0;
763
764 while (v > smtp_data && *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_size = -1;
805 acl_warn_headers = NULL;
806 queue_only_policy = FALSE;
807 deliver_freeze = FALSE; /* Can be set by ACL */
808 #ifdef WITH_CONTENT_SCAN
809 fake_reject = FALSE; /* Can be set by ACL */
810 no_mbox_unspool = FALSE; /* Can be set by ACL */
811 #endif
812 submission_mode = FALSE; /* Can be set by ACL */
813 active_local_from_check = local_from_check; /* Can be set by ACL */
814 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
815 sender_address = NULL;
816 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
817 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
818 sender_verified_list = NULL; /* No senders verified */
819 memset(sender_address_cache, 0, sizeof(sender_address_cache));
820 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
821 authenticated_sender = NULL;
822 #ifdef EXPERIMENTAL_BRIGHTMAIL
823 bmi_run = 0;
824 bmi_verdicts = NULL;
825 #endif
826 #ifdef EXPERIMENTAL_SPF
827 spf_header_comment = NULL;
828 spf_received = NULL;
829 spf_result = NULL;
830 spf_smtp_comment = NULL;
831 #endif
832 body_linecount = body_zerocount = 0;
833
834 for (i = 0; i < ACL_M_MAX; i++) acl_var[ACL_C_MAX + i] = NULL;
835
836 /* The message body variables use malloc store. They may be set if this is
837 not the first message in an SMTP session and the previous message caused them
838 to be referenced in an ACL. */
839
840 if (message_body != NULL)
841 {
842 store_free(message_body);
843 message_body = NULL;
844 }
845
846 if (message_body_end != NULL)
847 {
848 store_free(message_body_end);
849 message_body_end = NULL;
850 }
851
852 /* Warning log messages are also saved in malloc store. They are saved to avoid
853 repetition in the same message, but it seems right to repeat them for different
854 messagess. */
855
856 while (acl_warn_logged != NULL)
857 {
858 string_item *this = acl_warn_logged;
859 acl_warn_logged = acl_warn_logged->next;
860 store_free(this);
861 }
862 }
863
864
865
866
867
868 /*************************************************
869 * Initialize for incoming batched SMTP message *
870 *************************************************/
871
872 /* This function is called from smtp_setup_msg() in the case when
873 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
874 of messages in one file with SMTP commands between them. All errors must be
875 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
876 relevant. After an error on a sender, or an invalid recipient, the remainder
877 of the message is skipped. The value of received_protocol is already set.
878
879 Argument: none
880 Returns: > 0 message successfully started (reached DATA)
881 = 0 QUIT read or end of file reached
882 < 0 should not occur
883 */
884
885 static int
886 smtp_setup_batch_msg(void)
887 {
888 int done = 0;
889 void *reset_point = store_get(0);
890
891 /* Save the line count at the start of each transaction - single commands
892 like HELO and RSET count as whole transactions. */
893
894 bsmtp_transaction_linecount = receive_linecount;
895
896 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
897
898 smtp_reset(reset_point); /* Reset for start of message */
899
900 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
901 value. The values are 2 larger than the required yield of the function. */
902
903 while (done <= 0)
904 {
905 uschar *errmess;
906 uschar *recipient = NULL;
907 int start, end, sender_domain, recipient_domain;
908
909 switch(smtp_read_command(FALSE))
910 {
911 /* The HELO/EHLO commands set sender_address_helo if they have
912 valid data; otherwise they are ignored, except that they do
913 a reset of the state. */
914
915 case HELO_CMD:
916 case EHLO_CMD:
917
918 check_helo(smtp_data);
919 /* Fall through */
920
921 case RSET_CMD:
922 smtp_reset(reset_point);
923 bsmtp_transaction_linecount = receive_linecount;
924 break;
925
926
927 /* The MAIL FROM command requires an address as an operand. All we
928 do here is to parse it for syntactic correctness. The form "<>" is
929 a special case which converts into an empty string. The start/end
930 pointers in the original are not used further for this address, as
931 it is the canonical extracted address which is all that is kept. */
932
933 case MAIL_CMD:
934 if (sender_address != NULL)
935 /* The function moan_smtp_batch() does not return. */
936 moan_smtp_batch(cmd_buffer, "503 Sender already given");
937
938 if (smtp_data[0] == 0)
939 /* The function moan_smtp_batch() does not return. */
940 moan_smtp_batch(cmd_buffer, "501 MAIL FROM must have an address operand");
941
942 /* Reset to start of message */
943
944 smtp_reset(reset_point);
945
946 /* Apply SMTP rewrite */
947
948 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
949 rewrite_one(smtp_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
950 US"", global_rewrite_rules) : smtp_data;
951
952 /* Extract the address; the TRUE flag allows <> as valid */
953
954 raw_sender =
955 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
956 TRUE);
957
958 if (raw_sender == NULL)
959 /* The function moan_smtp_batch() does not return. */
960 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
961
962 sender_address = string_copy(raw_sender);
963
964 /* Qualify unqualified sender addresses if permitted to do so. */
965
966 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
967 {
968 if (allow_unqualified_sender)
969 {
970 sender_address = rewrite_address_qualify(sender_address, FALSE);
971 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
972 "and rewritten\n", raw_sender);
973 }
974 /* The function moan_smtp_batch() does not return. */
975 else moan_smtp_batch(cmd_buffer, "501 sender address must contain "
976 "a domain");
977 }
978 break;
979
980
981 /* The RCPT TO command requires an address as an operand. All we do
982 here is to parse it for syntactic correctness. There may be any number
983 of RCPT TO commands, specifying multiple senders. We build them all into
984 a data structure that is in argc/argv format. The start/end values
985 given by parse_extract_address are not used, as we keep only the
986 extracted address. */
987
988 case RCPT_CMD:
989 if (sender_address == NULL)
990 /* The function moan_smtp_batch() does not return. */
991 moan_smtp_batch(cmd_buffer, "503 No sender yet given");
992
993 if (smtp_data[0] == 0)
994 /* The function moan_smtp_batch() does not return. */
995 moan_smtp_batch(cmd_buffer, "501 RCPT TO must have an address operand");
996
997 /* Check maximum number allowed */
998
999 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1000 /* The function moan_smtp_batch() does not return. */
1001 moan_smtp_batch(cmd_buffer, "%s too many recipients",
1002 recipients_max_reject? "552": "452");
1003
1004 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1005 recipient address */
1006
1007 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1008 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
1009 global_rewrite_rules) : smtp_data;
1010
1011 /* rfc821_domains = TRUE; << no longer needed */
1012 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1013 &recipient_domain, FALSE);
1014 /* rfc821_domains = FALSE; << no longer needed */
1015
1016 if (recipient == NULL)
1017 /* The function moan_smtp_batch() does not return. */
1018 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
1019
1020 /* If the recipient address is unqualified, qualify it if permitted. Then
1021 add it to the list of recipients. */
1022
1023 if (recipient_domain == 0)
1024 {
1025 if (allow_unqualified_recipient)
1026 {
1027 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1028 recipient);
1029 recipient = rewrite_address_qualify(recipient, TRUE);
1030 }
1031 /* The function moan_smtp_batch() does not return. */
1032 else moan_smtp_batch(cmd_buffer, "501 recipient address must contain "
1033 "a domain");
1034 }
1035 receive_add_recipient(recipient, -1);
1036 break;
1037
1038
1039 /* The DATA command is legal only if it follows successful MAIL FROM
1040 and RCPT TO commands. This function is complete when a valid DATA
1041 command is encountered. */
1042
1043 case DATA_CMD:
1044 if (sender_address == NULL || recipients_count <= 0)
1045 {
1046 /* The function moan_smtp_batch() does not return. */
1047 if (sender_address == NULL)
1048 moan_smtp_batch(cmd_buffer,
1049 "503 MAIL FROM:<sender> command must precede DATA");
1050 else
1051 moan_smtp_batch(cmd_buffer,
1052 "503 RCPT TO:<recipient> must precede DATA");
1053 }
1054 else
1055 {
1056 done = 3; /* DATA successfully achieved */
1057 message_ended = END_NOTENDED; /* Indicate in middle of message */
1058 }
1059 break;
1060
1061
1062 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1063
1064 case VRFY_CMD:
1065 case EXPN_CMD:
1066 case HELP_CMD:
1067 case NOOP_CMD:
1068 case ETRN_CMD:
1069 bsmtp_transaction_linecount = receive_linecount;
1070 break;
1071
1072
1073 case EOF_CMD:
1074 case QUIT_CMD:
1075 done = 2;
1076 break;
1077
1078
1079 case BADARG_CMD:
1080 /* The function moan_smtp_batch() does not return. */
1081 moan_smtp_batch(cmd_buffer, "501 Unexpected argument data");
1082 break;
1083
1084
1085 case BADCHAR_CMD:
1086 /* The function moan_smtp_batch() does not return. */
1087 moan_smtp_batch(cmd_buffer, "501 Unexpected NULL in SMTP command");
1088 break;
1089
1090
1091 default:
1092 /* The function moan_smtp_batch() does not return. */
1093 moan_smtp_batch(cmd_buffer, "500 Command unrecognized");
1094 break;
1095 }
1096 }
1097
1098 return done - 2; /* Convert yield values */
1099 }
1100
1101
1102
1103
1104 /*************************************************
1105 * Start an SMTP session *
1106 *************************************************/
1107
1108 /* This function is called at the start of an SMTP session. Thereafter,
1109 smtp_setup_msg() is called to initiate each separate message. This
1110 function does host-specific testing, and outputs the banner line.
1111
1112 Arguments: none
1113 Returns: FALSE if the session can not continue; something has
1114 gone wrong, or the connection to the host is blocked
1115 */
1116
1117 BOOL
1118 smtp_start_session(void)
1119 {
1120 int size = 256;
1121 int i, ptr;
1122 uschar *p, *s, *ss;
1123
1124 helo_seen = esmtp = helo_accept_junk = FALSE;
1125 count_nonmail = TRUE_UNSET;
1126 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1127 smtp_delay_mail = smtp_rlm_base;
1128 auth_advertised = FALSE;
1129 pipelining_advertised = FALSE;
1130 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1131
1132 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1133
1134 sender_host_authenticated = NULL;
1135 authenticated_by = NULL;
1136
1137 #ifdef SUPPORT_TLS
1138 tls_cipher = tls_peerdn = NULL;
1139 tls_advertised = FALSE;
1140 #endif
1141
1142 /* Reset ACL connection variables */
1143
1144 for (i = 0; i < ACL_C_MAX; i++) acl_var[i] = NULL;
1145
1146 cmd_buffer = (uschar *)malloc(cmd_buffer_size + 1); /* allow for trailing 0 */
1147 if (cmd_buffer == NULL)
1148 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1149 "malloc() failed for SMTP command buffer");
1150
1151 /* For batched input, the protocol setting can be overridden from the
1152 command line by a trusted caller. */
1153
1154 if (smtp_batched_input)
1155 {
1156 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1157 }
1158
1159 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1160 reset later if any of EHLO/AUTH/STARTTLS are received. */
1161
1162 else
1163 received_protocol =
1164 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1165
1166 /* Set up the buffer for inputting using direct read() calls, and arrange to
1167 call the local functions instead of the standard C ones. */
1168
1169 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1170 if (smtp_inbuffer == NULL)
1171 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1172 receive_getc = smtp_getc;
1173 receive_ungetc = smtp_ungetc;
1174 receive_feof = smtp_feof;
1175 receive_ferror = smtp_ferror;
1176 smtp_inptr = smtp_inend = smtp_inbuffer;
1177 smtp_had_eof = smtp_had_error = 0;
1178
1179 /* Set up the message size limit; this may be host-specific */
1180
1181 thismessage_size_limit = expand_string_integer(message_size_limit);
1182 if (thismessage_size_limit < 0)
1183 {
1184 if (thismessage_size_limit == -1)
1185 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1186 "%s", expand_string_message);
1187 else
1188 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1189 "%s", expand_string_message);
1190 smtp_closedown(US"Temporary local problem - please try later");
1191 return FALSE;
1192 }
1193
1194 /* When a message is input locally via the -bs or -bS options, sender_host_
1195 unknown is set unless -oMa was used to force an IP address, in which case it
1196 is checked like a real remote connection. When -bs is used from inetd, this
1197 flag is not set, causing the sending host to be checked. The code that deals
1198 with IP source routing (if configured) is never required for -bs or -bS and
1199 the flag sender_host_notsocket is used to suppress it.
1200
1201 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1202 reserve for certain hosts and/or networks. */
1203
1204 if (!sender_host_unknown)
1205 {
1206 int rc;
1207 BOOL reserved_host = FALSE;
1208
1209 /* Look up IP options (source routing info) on the socket if this is not an
1210 -oMa "host", and if any are found, log them and drop the connection.
1211
1212 Linux (and others now, see below) is different to everyone else, so there
1213 has to be some conditional compilation here. Versions of Linux before 2.1.15
1214 used a structure whose name was "options". Somebody finally realized that
1215 this name was silly, and it got changed to "ip_options". I use the
1216 newer name here, but there is a fudge in the script that sets up os.h
1217 to define a macro in older Linux systems.
1218
1219 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1220 glibc 2, which has chosen ip_opts for the structure name. This is now
1221 really a glibc thing rather than a Linux thing, so the condition name
1222 has been changed to reflect this. It is relevant also to GNU/Hurd.
1223
1224 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1225 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1226 a special macro defined in the os.h file.
1227
1228 Some DGUX versions on older hardware appear not to support IP options at
1229 all, so there is now a general macro which can be set to cut out this
1230 support altogether.
1231
1232 How to do this properly in IPv6 is not yet known. */
1233
1234 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1235
1236 #ifdef GLIBC_IP_OPTIONS
1237 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1238 #define OPTSTYLE 1
1239 #else
1240 #define OPTSTYLE 2
1241 #endif
1242 #elif defined DARWIN_IP_OPTIONS
1243 #define OPTSTYLE 2
1244 #else
1245 #define OPTSTYLE 3
1246 #endif
1247
1248 if (!host_checking && !sender_host_notsocket)
1249 {
1250 #if OPTSTYLE == 1
1251 SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1252 struct ip_options *ipopt = store_get(optlen);
1253 #elif OPTSTYLE == 2
1254 struct ip_opts ipoptblock;
1255 struct ip_opts *ipopt = &ipoptblock;
1256 SOCKLEN_T optlen = sizeof(ipoptblock);
1257 #else
1258 struct ipoption ipoptblock;
1259 struct ipoption *ipopt = &ipoptblock;
1260 SOCKLEN_T optlen = sizeof(ipoptblock);
1261 #endif
1262
1263 /* Occasional genuine failures of getsockopt() have been seen - for
1264 example, "reset by peer". Therefore, just log and give up on this
1265 call, unless the error is ENOPROTOOPT. This error is given by systems
1266 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1267 of writing. So for that error, carry on - we just can't do an IP options
1268 check. */
1269
1270 DEBUG(D_receive) debug_printf("checking for IP options\n");
1271
1272 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1273 &optlen) < 0)
1274 {
1275 if (errno != ENOPROTOOPT)
1276 {
1277 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1278 host_and_ident(FALSE), strerror(errno));
1279 smtp_printf("451 SMTP service not available\r\n");
1280 return FALSE;
1281 }
1282 }
1283
1284 /* Deal with any IP options that are set. On the systems I have looked at,
1285 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1286 more logging data than will fit in big_buffer. Nevertheless, after somebody
1287 questioned this code, I've added in some paranoid checking. */
1288
1289 else if (optlen > 0)
1290 {
1291 uschar *p = big_buffer;
1292 uschar *pend = big_buffer + big_buffer_size;
1293 uschar *opt, *adptr;
1294 int optcount;
1295 struct in_addr addr;
1296
1297 #if OPTSTYLE == 1
1298 uschar *optstart = (uschar *)(ipopt->__data);
1299 #elif OPTSTYLE == 2
1300 uschar *optstart = (uschar *)(ipopt->ip_opts);
1301 #else
1302 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1303 #endif
1304
1305 DEBUG(D_receive) debug_printf("IP options exist\n");
1306
1307 Ustrcpy(p, "IP options on incoming call:");
1308 p += Ustrlen(p);
1309
1310 for (opt = optstart; opt != NULL &&
1311 opt < (uschar *)(ipopt) + optlen;)
1312 {
1313 switch (*opt)
1314 {
1315 case IPOPT_EOL:
1316 opt = NULL;
1317 break;
1318
1319 case IPOPT_NOP:
1320 opt++;
1321 break;
1322
1323 case IPOPT_SSRR:
1324 case IPOPT_LSRR:
1325 if (!string_format(p, pend-p, " %s [@%s",
1326 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1327 #if OPTSTYLE == 1
1328 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1329 #elif OPTSTYLE == 2
1330 inet_ntoa(ipopt->ip_dst)))
1331 #else
1332 inet_ntoa(ipopt->ipopt_dst)))
1333 #endif
1334 {
1335 opt = NULL;
1336 break;
1337 }
1338
1339 p += Ustrlen(p);
1340 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1341 adptr = opt + 3;
1342 while (optcount-- > 0)
1343 {
1344 memcpy(&addr, adptr, sizeof(addr));
1345 if (!string_format(p, pend - p - 1, "%s%s",
1346 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1347 {
1348 opt = NULL;
1349 break;
1350 }
1351 p += Ustrlen(p);
1352 adptr += sizeof(struct in_addr);
1353 }
1354 *p++ = ']';
1355 opt += opt[1];
1356 break;
1357
1358 default:
1359 {
1360 int i;
1361 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1362 Ustrcat(p, "[ ");
1363 p += 2;
1364 for (i = 0; i < opt[1]; i++)
1365 {
1366 sprintf(CS p, "%2.2x ", opt[i]);
1367 p += 3;
1368 }
1369 *p++ = ']';
1370 }
1371 opt += opt[1];
1372 break;
1373 }
1374 }
1375
1376 *p = 0;
1377 log_write(0, LOG_MAIN, "%s", big_buffer);
1378
1379 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1380
1381 log_write(0, LOG_MAIN|LOG_REJECT,
1382 "connection from %s refused (IP options)", host_and_ident(FALSE));
1383
1384 smtp_printf("554 SMTP service not available\r\n");
1385 return FALSE;
1386 }
1387
1388 /* Length of options = 0 => there are no options */
1389
1390 else DEBUG(D_receive) debug_printf("no IP options found\n");
1391 }
1392 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1393
1394 /* Set keep-alive in socket options. The option is on by default. This
1395 setting is an attempt to get rid of some hanging connections that stick in
1396 read() when the remote end (usually a dialup) goes away. */
1397
1398 if (smtp_accept_keepalive && !sender_host_notsocket)
1399 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1400
1401 /* If the current host matches host_lookup, set the name by doing a
1402 reverse lookup. On failure, sender_host_name will be NULL and
1403 host_lookup_failed will be TRUE. This may or may not be serious - optional
1404 checks later. */
1405
1406 if (verify_check_host(&host_lookup) == OK)
1407 {
1408 (void)host_name_lookup();
1409 host_build_sender_fullhost();
1410 }
1411
1412 /* Delay this until we have the full name, if it is looked up. */
1413
1414 set_process_info("handling incoming connection from %s",
1415 host_and_ident(FALSE));
1416
1417 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1418 smtps port for use with older style SSL MTAs. */
1419
1420 #ifdef SUPPORT_TLS
1421 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1422 return FALSE;
1423 #endif
1424
1425 /* Test for explicit connection rejection */
1426
1427 if (verify_check_host(&host_reject_connection) == OK)
1428 {
1429 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1430 "from %s (host_reject_connection)", host_and_ident(FALSE));
1431 smtp_printf("554 SMTP service not available\r\n");
1432 return FALSE;
1433 }
1434
1435 /* Test with TCP Wrappers if so configured */
1436
1437 #ifdef USE_TCP_WRAPPERS
1438 if (!hosts_ctl("exim",
1439 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1440 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1441 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1442 {
1443 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1444 log_write(L_connection_reject,
1445 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1446 "(tcp wrappers)", host_and_ident(FALSE));
1447 smtp_printf("554 SMTP service not available\r\n");
1448 return FALSE;
1449 }
1450 #endif
1451
1452 /* Check for reserved slots. Note that the count value doesn't include
1453 this process, as it gets upped in the parent process. */
1454
1455 if (smtp_accept_max > 0 &&
1456 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1457 {
1458 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1459 {
1460 log_write(L_connection_reject,
1461 LOG_MAIN, "temporarily refused connection from %s: not in "
1462 "reserve list: connected=%d max=%d reserve=%d%s",
1463 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1464 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1465 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1466 "please try again later\r\n", smtp_active_hostname);
1467 return FALSE;
1468 }
1469 reserved_host = TRUE;
1470 }
1471
1472 /* If a load level above which only messages from reserved hosts are
1473 accepted is set, check the load. For incoming calls via the daemon, the
1474 check is done in the superior process if there are no reserved hosts, to
1475 save a fork. In all cases, the load average will already be available
1476 in a global variable at this point. */
1477
1478 if (smtp_load_reserve >= 0 &&
1479 load_average > smtp_load_reserve &&
1480 !reserved_host &&
1481 verify_check_host(&smtp_reserve_hosts) != OK)
1482 {
1483 log_write(L_connection_reject,
1484 LOG_MAIN, "temporarily refused connection from %s: not in "
1485 "reserve list and load average = %.2f", host_and_ident(FALSE),
1486 (double)load_average/1000.0);
1487 smtp_printf("421 %s: Too much load; please try again later\r\n",
1488 smtp_active_hostname);
1489 return FALSE;
1490 }
1491
1492 /* Determine whether unqualified senders or recipients are permitted
1493 for this host. Unfortunately, we have to do this every time, in order to
1494 set the flags so that they can be inspected when considering qualifying
1495 addresses in the headers. For a site that permits no qualification, this
1496 won't take long, however. */
1497
1498 allow_unqualified_sender =
1499 verify_check_host(&sender_unqualified_hosts) == OK;
1500
1501 allow_unqualified_recipient =
1502 verify_check_host(&recipient_unqualified_hosts) == OK;
1503
1504 /* Determine whether HELO/EHLO is required for this host. The requirement
1505 can be hard or soft. */
1506
1507 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1508 if (!helo_required)
1509 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1510
1511 /* Determine whether this hosts is permitted to send syntactic junk
1512 after a HELO or EHLO command. */
1513
1514 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1515 }
1516
1517 /* For batch SMTP input we are now done. */
1518
1519 if (smtp_batched_input) return TRUE;
1520
1521 /* Run the ACL if it exists */
1522
1523 if (acl_smtp_connect != NULL)
1524 {
1525 int rc;
1526 uschar *user_msg, *log_msg;
1527 smtp_data = US"in \"connect\" ACL"; /* For logged failure message */
1528 rc = acl_check(ACL_WHERE_CONNECT, US"", acl_smtp_connect, &user_msg,
1529 &log_msg);
1530 if (rc != OK)
1531 {
1532 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1533 return FALSE;
1534 }
1535 }
1536
1537 /* Output the initial message for a two-way SMTP connection. It may contain
1538 newlines, which then cause a multi-line response to be given. */
1539
1540 s = expand_string(smtp_banner);
1541 if (s == NULL)
1542 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1543 "failed: %s", smtp_banner, expand_string_message);
1544
1545 /* Remove any terminating newlines; might as well remove trailing space too */
1546
1547 p = s + Ustrlen(s);
1548 while (p > s && isspace(p[-1])) p--;
1549 *p = 0;
1550
1551 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1552 is all contained in a single IP packet. The original code wrote out the
1553 greeting using several calls to fprint/fputc, and on busy servers this could
1554 cause it to be split over more than one packet - which caused CC:Mail to fall
1555 over when it got the second part of the greeting after sending its first
1556 command. Sigh. To try to avoid this, build the complete greeting message
1557 first, and output it in one fell swoop. This gives a better chance of it
1558 ending up as a single packet. */
1559
1560 ss = store_get(size);
1561 ptr = 0;
1562
1563 p = s;
1564 do /* At least once, in case we have an empty string */
1565 {
1566 int len;
1567 uschar *linebreak = Ustrchr(p, '\n');
1568 if (linebreak == NULL)
1569 {
1570 len = Ustrlen(p);
1571 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1572 }
1573 else
1574 {
1575 len = linebreak - p;
1576 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1577 }
1578 ss = string_cat(ss, &size, &ptr, p, len);
1579 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1580 p += len;
1581 if (linebreak != NULL) p++;
1582 }
1583 while (*p != 0);
1584
1585 ss[ptr] = 0; /* string_cat leaves room for this */
1586
1587 /* Before we write the banner, check that there is no input pending, unless
1588 this synchronisation check is disabled. */
1589
1590 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1591 {
1592 fd_set fds;
1593 struct timeval tzero;
1594 tzero.tv_sec = 0;
1595 tzero.tv_usec = 0;
1596 FD_ZERO(&fds);
1597 FD_SET(fileno(smtp_in), &fds);
1598 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1599 &tzero) > 0)
1600 {
1601 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: "
1602 "synchronization error (input sent without waiting for greeting): "
1603 "rejected connection from %s", host_and_ident(TRUE));
1604 smtp_printf("554 SMTP synchronization error\r\n");
1605 return FALSE;
1606 }
1607 }
1608
1609 /* Now output the banner */
1610
1611 smtp_printf("%s", ss);
1612 return TRUE;
1613 }
1614
1615
1616
1617
1618
1619 /*************************************************
1620 * Handle SMTP syntax and protocol errors *
1621 *************************************************/
1622
1623 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1624 to do so. Then transmit the error response. The return value depends on the
1625 number of syntax and protocol errors in this SMTP session.
1626
1627 Arguments:
1628 type error type, given as a log flag bit
1629 code response code; <= 0 means don't send a response
1630 data data to reflect in the response (can be NULL)
1631 errmess the error message
1632
1633 Returns: -1 limit of syntax/protocol errors NOT exceeded
1634 +1 limit of syntax/protocol errors IS exceeded
1635
1636 These values fit in with the values of the "done" variable in the main
1637 processing loop in smtp_setup_msg(). */
1638
1639 static int
1640 synprot_error(int type, int code, uschar *data, uschar *errmess)
1641 {
1642 int yield = -1;
1643
1644 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1645 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1646 string_printing(cmd_buffer), host_and_ident(TRUE), errmess);
1647
1648 if (++synprot_error_count > smtp_max_synprot_errors)
1649 {
1650 yield = 1;
1651 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1652 "syntax or protocol errors (last command was \"%s\")",
1653 host_and_ident(FALSE), cmd_buffer);
1654 }
1655
1656 if (code > 0)
1657 {
1658 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1659 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1660 if (yield == 1)
1661 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1662 }
1663
1664 return yield;
1665 }
1666
1667
1668
1669
1670 /*************************************************
1671 * Log incomplete transactions *
1672 *************************************************/
1673
1674 /* This function is called after a transaction has been aborted by RSET, QUIT,
1675 connection drops or other errors. It logs the envelope information received
1676 so far in order to preserve address verification attempts.
1677
1678 Argument: string to indicate what aborted the transaction
1679 Returns: nothing
1680 */
1681
1682 static void
1683 incomplete_transaction_log(uschar *what)
1684 {
1685 if (sender_address == NULL || /* No transaction in progress */
1686 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1687 ) return;
1688
1689 /* Build list of recipients for logging */
1690
1691 if (recipients_count > 0)
1692 {
1693 int i;
1694 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1695 for (i = 0; i < recipients_count; i++)
1696 raw_recipients[i] = recipients_list[i].address;
1697 raw_recipients_count = recipients_count;
1698 }
1699
1700 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1701 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1702 }
1703
1704
1705
1706
1707 /*************************************************
1708 * Send SMTP response, possibly multiline *
1709 *************************************************/
1710
1711 /* There are, it seems, broken clients out there that cannot handle multiline
1712 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1713 output nothing for non-final calls, and only the first line for anything else.
1714
1715 Arguments:
1716 code SMTP code
1717 final FALSE if the last line isn't the final line
1718 msg message text, possibly containing newlines
1719
1720 Returns: nothing
1721 */
1722
1723 void
1724 smtp_respond(int code, BOOL final, uschar *msg)
1725 {
1726 if (!final && no_multiline_responses) return;
1727
1728 for (;;)
1729 {
1730 uschar *nl = Ustrchr(msg, '\n');
1731 if (nl == NULL)
1732 {
1733 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1734 return;
1735 }
1736 else if (nl[1] == 0 || no_multiline_responses)
1737 {
1738 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1739 return;
1740 }
1741 else
1742 {
1743 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1744 msg = nl + 1;
1745 while (isspace(*msg)) msg++;
1746 }
1747 }
1748 }
1749
1750
1751
1752
1753 /*************************************************
1754 * Handle an ACL failure *
1755 *************************************************/
1756
1757 /* This function is called when acl_check() fails. As well as calls from within
1758 this module, it is called from receive.c for an ACL after DATA. It sorts out
1759 logging the incident, and sets up the error response. A message containing
1760 newlines is turned into a multiline SMTP response, but for logging, only the
1761 first line is used.
1762
1763 There's a table of the response codes to use in globals.c, along with the table
1764 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1765 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1766 that the response should be 252 in the disabled state, because there are broken
1767 clients that try VRFY before RCPT. A 5xx response should be given only when the
1768 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1769 given on refusal, and for AUTH, 503.
1770
1771 Arguments:
1772 where where the ACL was called from
1773 rc the failure code
1774 user_msg a message that can be included in an SMTP response
1775 log_msg a message for logging
1776
1777 Returns: 0 in most cases
1778 2 if the failure code was FAIL_DROP, in which case the
1779 SMTP connection should be dropped (this value fits with the
1780 "done" variable in smtp_setup_msg() below)
1781 */
1782
1783 int
1784 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1785 {
1786 int code = acl_wherecodes[where];
1787 BOOL drop = rc == FAIL_DROP;
1788 uschar *lognl;
1789 uschar *sender_info = US"";
1790 uschar *what = (where == ACL_WHERE_PREDATA)? US"DATA" :
1791 #ifdef WITH_CONTENT_SCAN
1792 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1793 #endif
1794 (where == ACL_WHERE_DATA)? US"after DATA" :
1795 string_sprintf("%s %s", acl_wherenames[where], smtp_data);
1796
1797 if (drop) rc = FAIL;
1798
1799 /* We used to have sender_address here; however, there was a bug that was not
1800 updating sender_address after a rewrite during a verify. When this bug was
1801 fixed, sender_address at this point became the rewritten address. I'm not sure
1802 this is what should be logged, so I've changed to logging the unrewritten
1803 address to retain backward compatibility. */
1804
1805 #ifndef WITH_CONTENT_SCAN
1806 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1807 #else
1808 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1809 #endif
1810 {
1811 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1812 sender_address_unrewritten : sender_address);
1813 }
1814
1815 /* If there's been a sender verification failure with a specific message, and
1816 we have not sent a response about it yet, do so now, as a preliminary line for
1817 failures, but not defers. However, log it in both cases. */
1818
1819 if (sender_verified_failed != NULL &&
1820 !testflag(sender_verified_failed, af_sverify_told))
1821 {
1822 setflag(sender_verified_failed, af_sverify_told);
1823
1824 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1825 host_and_ident(TRUE),
1826 ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail",
1827 sender_verified_failed->address,
1828 (sender_verified_failed->message == NULL)? US"" :
1829 string_sprintf(": %s", sender_verified_failed->message));
1830
1831 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1832 smtp_respond(code, FALSE, string_sprintf(
1833 testflag(sender_verified_failed, af_verify_pmfail)?
1834 "Postmaster verification failed while checking <%s>\n%s\n"
1835 "Several RFCs state that you are required to have a postmaster\n"
1836 "mailbox for each mail domain. This host does not accept mail\n"
1837 "from domains whose servers reject the postmaster address."
1838 :
1839 testflag(sender_verified_failed, af_verify_nsfail)?
1840 "Callback setup failed while verifying <%s>\n%s\n"
1841 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1842 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1843 "RFC requirements, and stops you from receiving standard bounce\n"
1844 "messages. This host does not accept mail from domains whose servers\n"
1845 "refuse bounces."
1846 :
1847 "Verification failed for <%s>\n%s",
1848 sender_verified_failed->address,
1849 sender_verified_failed->user_message));
1850 }
1851
1852 /* Sort out text for logging */
1853
1854 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1855 lognl = Ustrchr(log_msg, '\n');
1856 if (lognl != NULL) *lognl = 0;
1857
1858 /* Send permanent failure response to the command, but the code used isn't
1859 always a 5xx one - see comments at the start of this function. If the original
1860 rc was FAIL_DROP we drop the connection and yield 2. */
1861
1862 if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1863 US"Administrative prohibition" : user_msg);
1864
1865 /* Send temporary failure response to the command. Don't give any details,
1866 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1867 verb, and for a header verify when smtp_return_error_details is set.
1868
1869 This conditional logic is all somewhat of a mess because of the odd
1870 interactions between temp_details and return_error_details. One day it should
1871 be re-implemented in a tidier fashion. */
1872
1873 else
1874 {
1875 if (acl_temp_details && user_msg != NULL)
1876 {
1877 if (smtp_return_error_details &&
1878 sender_verified_failed != NULL &&
1879 sender_verified_failed->message != NULL)
1880 {
1881 smtp_respond(451, FALSE, sender_verified_failed->message);
1882 }
1883 smtp_respond(451, TRUE, user_msg);
1884 }
1885 else
1886 smtp_printf("451 Temporary local problem - please try later\r\n");
1887 }
1888
1889 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
1890 Otherwise, log why it is closing if required and return 2. */
1891
1892 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1893 host_and_ident(TRUE),
1894 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1895
1896 if (!drop) return 0;
1897
1898 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1899 smtp_get_connection_info());
1900 return 2;
1901 }
1902
1903
1904
1905
1906 /*************************************************
1907 * Initialize for SMTP incoming message *
1908 *************************************************/
1909
1910 /* This function conducts the initial dialogue at the start of an incoming SMTP
1911 message, and builds a list of recipients. However, if the incoming message
1912 is part of a batch (-bS option) a separate function is called since it would
1913 be messy having tests splattered about all over this function. This function
1914 therefore handles the case where interaction is occurring. The input and output
1915 files are set up in smtp_in and smtp_out.
1916
1917 The global recipients_list is set to point to a vector of recipient_item
1918 blocks, whose number is given by recipients_count. This is extended by the
1919 receive_add_recipient() function. The global variable sender_address is set to
1920 the sender's address. The yield is +1 if a message has been successfully
1921 started, 0 if a QUIT command was encountered or the connection was refused from
1922 the particular host, or -1 if the connection was lost.
1923
1924 Argument: none
1925
1926 Returns: > 0 message successfully started (reached DATA)
1927 = 0 QUIT read or end of file reached or call refused
1928 < 0 lost connection
1929 */
1930
1931 int
1932 smtp_setup_msg(void)
1933 {
1934 int done = 0;
1935 BOOL toomany = FALSE;
1936 BOOL discarded = FALSE;
1937 BOOL last_was_rej_mail = FALSE;
1938 BOOL last_was_rcpt = FALSE;
1939 void *reset_point = store_get(0);
1940
1941 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
1942
1943 /* Reset for start of new message. We allow one RSET not to be counted as a
1944 nonmail command, for those MTAs that insist on sending it between every
1945 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
1946 TLS between messages (an Exim client may do this if it has messages queued up
1947 for the host). Note: we do NOT reset AUTH at this point. */
1948
1949 smtp_reset(reset_point);
1950 message_ended = END_NOTSTARTED;
1951
1952 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
1953 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
1954 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
1955 #ifdef SUPPORT_TLS
1956 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
1957 #endif
1958
1959 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
1960
1961 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
1962
1963 /* Batched SMTP is handled in a different function. */
1964
1965 if (smtp_batched_input) return smtp_setup_batch_msg();
1966
1967 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1968 value. The values are 2 larger than the required yield of the function. */
1969
1970 while (done <= 0)
1971 {
1972 uschar **argv;
1973 uschar *etrn_command;
1974 uschar *etrn_serialize_key;
1975 uschar *errmess;
1976 uschar *user_msg, *log_msg;
1977 uschar *recipient = NULL;
1978 uschar *hello = NULL;
1979 uschar *set_id = NULL;
1980 uschar *s, *ss;
1981 BOOL was_rej_mail = FALSE;
1982 BOOL was_rcpt = FALSE;
1983 void (*oldsignal)(int);
1984 pid_t pid;
1985 int start, end, sender_domain, recipient_domain;
1986 int ptr, size, rc;
1987 int c;
1988 auth_instance *au;
1989
1990 switch(smtp_read_command(TRUE))
1991 {
1992 /* The AUTH command is not permitted to occur inside a transaction, and may
1993 occur successfully only once per connection, and then only when we've
1994 advertised it. Actually, that isn't quite true. When TLS is started, all
1995 previous information about a connection must be discarded, so a new AUTH is
1996 permitted at that time.
1997
1998 AUTH is initially labelled as a "nonmail command" so that one occurrence
1999 doesn't get counted. We change the label here so that multiple failing
2000 AUTHS will eventually hit the nonmail threshold. */
2001
2002 case AUTH_CMD:
2003 authentication_failed = TRUE;
2004 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2005
2006 if (!auth_advertised)
2007 {
2008 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2009 US"AUTH command used when not advertised");
2010 break;
2011 }
2012 if (sender_host_authenticated != NULL)
2013 {
2014 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2015 US"already authenticated");
2016 break;
2017 }
2018 if (sender_address != NULL)
2019 {
2020 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2021 US"not permitted in mail transaction");
2022 break;
2023 }
2024
2025 /* Check the ACL */
2026
2027 if (acl_smtp_auth != NULL)
2028 {
2029 rc = acl_check(ACL_WHERE_AUTH, smtp_data, acl_smtp_auth, &user_msg,
2030 &log_msg);
2031 if (rc != OK)
2032 {
2033 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2034 break;
2035 }
2036 }
2037
2038 /* Find the name of the requested authentication mechanism. */
2039
2040 s = smtp_data;
2041 while ((c = *smtp_data) != 0 && !isspace(c))
2042 {
2043 if (!isalnum(c) && c != '-' && c != '_')
2044 {
2045 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2046 US"invalid character in authentication mechanism name");
2047 goto COMMAND_LOOP;
2048 }
2049 smtp_data++;
2050 }
2051
2052 /* If not at the end of the line, we must be at white space. Terminate the
2053 name and move the pointer on to any data that may be present. */
2054
2055 if (*smtp_data != 0)
2056 {
2057 *smtp_data++ = 0;
2058 while (isspace(*smtp_data)) smtp_data++;
2059 }
2060
2061 /* Search for an authentication mechanism which is configured for use
2062 as a server and which has been advertised. */
2063
2064 for (au = auths; au != NULL; au = au->next)
2065 {
2066 if (strcmpic(s, au->public_name) == 0 && au->server &&
2067 au->advertised) break;
2068 }
2069
2070 if (au == NULL)
2071 {
2072 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2073 string_sprintf("%s authentication mechanism not supported", s));
2074 break;
2075 }
2076
2077 /* Run the checking code, passing the remainder of the command
2078 line as data. Initialize $0 empty. The authenticator may set up
2079 other numeric variables. Afterwards, have a go at expanding the set_id
2080 string, even if authentication failed - for bad passwords it can be useful
2081 to log the userid. On success, require set_id to expand and exist, and
2082 put it in authenticated_id. Save this in permanent store, as the working
2083 store gets reset at HELO, RSET, etc. */
2084
2085 expand_nmax = 0;
2086 expand_nlength[0] = 0; /* $0 contains nothing */
2087
2088 c = (au->info->servercode)(au, smtp_data);
2089 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2090 expand_nmax = -1; /* Reset numeric variables */
2091
2092 /* For the non-OK cases, set up additional logging data if set_id
2093 is not empty. */
2094
2095 if (c != OK)
2096 {
2097 if (set_id != NULL && *set_id != 0)
2098 set_id = string_sprintf(" (set_id=%s)", set_id);
2099 else set_id = US"";
2100 }
2101
2102 /* Switch on the result */
2103
2104 switch(c)
2105 {
2106 case OK:
2107 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2108 {
2109 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2110 sender_host_authenticated = au->name;
2111 authentication_failed = FALSE;
2112 received_protocol =
2113 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2114 ((sender_host_address != NULL)? pnlocal : 0);
2115 s = ss = US"235 Authentication succeeded";
2116 authenticated_by = au;
2117 break;
2118 }
2119
2120 /* Authentication succeeded, but we failed to expand the set_id string.
2121 Treat this as a temporary error. */
2122
2123 auth_defer_msg = expand_string_message;
2124 /* Fall through */
2125
2126 case DEFER:
2127 s = string_sprintf("435 Unable to authenticate at present%s",
2128 auth_defer_user_msg);
2129 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2130 set_id, auth_defer_msg);
2131 break;
2132
2133 case BAD64:
2134 s = ss = US"501 Invalid base64 data";
2135 break;
2136
2137 case CANCELLED:
2138 s = ss = US"501 Authentication cancelled";
2139 break;
2140
2141 case UNEXPECTED:
2142 s = ss = US"553 Initial data not expected";
2143 break;
2144
2145 case FAIL:
2146 s = US"535 Incorrect authentication data";
2147 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2148 break;
2149
2150 default:
2151 s = US"435 Internal error";
2152 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2153 "check", set_id, c);
2154 break;
2155 }
2156
2157 smtp_printf("%s\r\n", s);
2158 if (c != OK)
2159 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2160 au->name, host_and_ident(FALSE), ss);
2161
2162 break; /* AUTH_CMD */
2163
2164 /* The HELO/EHLO commands are permitted to appear in the middle of a
2165 session as well as at the beginning. They have the effect of a reset in
2166 addition to their other functions. Their absence at the start cannot be
2167 taken to be an error.
2168
2169 RFC 2821 says:
2170
2171 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2172 or 502 failure replies MUST be returned as appropriate. The SMTP
2173 server MUST stay in the same state after transmitting these replies
2174 that it was in before the EHLO was received.
2175
2176 Therefore, we do not do the reset until after checking the command for
2177 acceptability. This change was made for Exim release 4.11. Previously
2178 it did the reset first. */
2179
2180 case HELO_CMD:
2181 hello = US"HELO";
2182 esmtp = FALSE;
2183 goto HELO_EHLO;
2184
2185 case EHLO_CMD:
2186 hello = US"EHLO";
2187 esmtp = TRUE;
2188
2189 HELO_EHLO: /* Common code for HELO and EHLO */
2190 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2191 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2192
2193 /* Reject the HELO if its argument was invalid or non-existent. A
2194 successful check causes the argument to be saved in malloc store. */
2195
2196 if (!check_helo(smtp_data))
2197 {
2198 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2199
2200 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2201 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2202 (*smtp_data == 0)? US"(no argument given)" :
2203 string_printing(smtp_data));
2204
2205 if (++synprot_error_count > smtp_max_synprot_errors)
2206 {
2207 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2208 "syntax or protocol errors (last command was \"%s\")",
2209 host_and_ident(FALSE), cmd_buffer);
2210 done = 1;
2211 }
2212
2213 break;
2214 }
2215
2216 /* If sender_host_unknown is true, we have got here via the -bs interface,
2217 not called from inetd. Otherwise, we are running an IP connection and the
2218 host address will be set. If the helo name is the primary name of this
2219 host and we haven't done a reverse lookup, force one now. If helo_required
2220 is set, ensure that the HELO name matches the actual host. If helo_verify
2221 is set, do the same check, but softly. */
2222
2223 if (!sender_host_unknown)
2224 {
2225 BOOL old_helo_verified = helo_verified;
2226 uschar *p = smtp_data;
2227
2228 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2229 *p = 0;
2230
2231 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2232 because otherwise the log can be confusing. */
2233
2234 if (sender_host_name == NULL &&
2235 (deliver_domain = sender_helo_name, /* set $domain */
2236 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2237 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2238 (void)host_name_lookup();
2239
2240 /* Rebuild the fullhost info to include the HELO name (and the real name
2241 if it was looked up.) */
2242
2243 host_build_sender_fullhost(); /* Rebuild */
2244 set_process_info("handling%s incoming connection from %s",
2245 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2246
2247 /* Verify if configured. This doesn't give much security, but it does
2248 make some people happy to be able to do it. Note that HELO is legitimately
2249 allowed to quote an address literal. Allow for IPv6 ::ffff: literals. */
2250
2251 helo_verified = FALSE;
2252 if (helo_required || helo_verify)
2253 {
2254 BOOL tempfail = FALSE;
2255
2256 HDEBUG(D_receive) debug_printf("verifying %s %s\n", hello,
2257 sender_helo_name);
2258 if (sender_helo_name[0] == '[')
2259 {
2260 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2261 Ustrlen(sender_host_address)) == 0;
2262
2263 #if HAVE_IPV6
2264 if (!helo_verified)
2265 {
2266 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2267 helo_verified = Ustrncmp(sender_helo_name + 1,
2268 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2269 }
2270 #endif
2271
2272 HDEBUG(D_receive)
2273 { if (helo_verified) debug_printf("matched host address\n"); }
2274 }
2275
2276 /* Do a reverse lookup if one hasn't already given a positive or
2277 negative response. If that fails, or the name doesn't match, try
2278 checking with a forward lookup. */
2279
2280 else
2281 {
2282 if (sender_host_name == NULL && !host_lookup_failed)
2283 tempfail = host_name_lookup() == DEFER;
2284
2285 /* If a host name is known, check it and all its aliases. */
2286
2287 if (sender_host_name != NULL)
2288 {
2289 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2290
2291 if (helo_verified)
2292 {
2293 HDEBUG(D_receive) debug_printf("matched host name\n");
2294 }
2295 else
2296 {
2297 uschar **aliases = sender_host_aliases;
2298 while (*aliases != NULL)
2299 {
2300 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2301 if (helo_verified) break;
2302 }
2303 HDEBUG(D_receive)
2304 {
2305 if (helo_verified)
2306 debug_printf("matched alias %s\n", *(--aliases));
2307 }
2308 }
2309 }
2310
2311 /* Final attempt: try a forward lookup of the helo name */
2312
2313 if (!helo_verified)
2314 {
2315 int rc;
2316 host_item h;
2317 h.name = sender_helo_name;
2318 h.address = NULL;
2319 h.mx = MX_NONE;
2320 h.next = NULL;
2321 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2322 sender_helo_name);
2323 rc = host_find_byname(&h, NULL, NULL, TRUE);
2324 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2325 {
2326 host_item *hh = &h;
2327 while (hh != NULL)
2328 {
2329 if (Ustrcmp(hh->address, sender_host_address) == 0)
2330 {
2331 helo_verified = TRUE;
2332 HDEBUG(D_receive)
2333 debug_printf("IP address for %s matches calling address\n",
2334 sender_helo_name);
2335 break;
2336 }
2337 hh = hh->next;
2338 }
2339 }
2340 }
2341 }
2342
2343 /* Verification failed. A temporary lookup failure gives a temporary
2344 error. */
2345
2346 if (!helo_verified)
2347 {
2348 if (helo_required)
2349 {
2350 smtp_printf("%d %s argument does not match calling host\r\n",
2351 tempfail? 451 : 550, hello);
2352 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2353 tempfail? "temporarily " : "",
2354 hello, sender_helo_name, host_and_ident(FALSE));
2355 helo_verified = old_helo_verified;
2356 break; /* End of HELO/EHLO processing */
2357 }
2358 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2359 "helo_try_verify_hosts\n", hello);
2360 }
2361 }
2362 }
2363
2364 #ifdef EXPERIMENTAL_SPF
2365 /* set up SPF context */
2366 spf_init(sender_helo_name, sender_host_address);
2367 #endif
2368
2369 /* Apply an ACL check if one is defined */
2370
2371 if (acl_smtp_helo != NULL)
2372 {
2373 rc = acl_check(ACL_WHERE_HELO, smtp_data, acl_smtp_helo, &user_msg,
2374 &log_msg);
2375 if (rc != OK)
2376 {
2377 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2378 sender_helo_name = NULL;
2379 host_build_sender_fullhost(); /* Rebuild */
2380 break;
2381 }
2382 }
2383
2384 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2385 abandoning any previous message. */
2386
2387 received_protocol = (esmtp?
2388 protocols[pextend +
2389 ((sender_host_authenticated != NULL)? pauthed : 0) +
2390 ((tls_active >= 0)? pcrpted : 0)]
2391 :
2392 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2393 +
2394 ((sender_host_address != NULL)? pnlocal : 0);
2395
2396 smtp_reset(reset_point);
2397 toomany = FALSE;
2398
2399 /* Generate an OK reply, including the ident if present, and also
2400 the IP address if present. Reflecting back the ident is intended
2401 as a deterrent to mail forgers. For maximum efficiency, and also
2402 because some broken systems expect each response to be in a single
2403 packet, arrange that it is sent in one write(). */
2404
2405 auth_advertised = FALSE;
2406 pipelining_advertised = FALSE;
2407 #ifdef SUPPORT_TLS
2408 tls_advertised = FALSE;
2409 #endif
2410
2411 s = string_sprintf("250 %s Hello %s%s%s",
2412 smtp_active_hostname,
2413 (sender_ident == NULL)? US"" : sender_ident,
2414 (sender_ident == NULL)? US"" : US" at ",
2415 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2416
2417 ptr = Ustrlen(s);
2418 size = ptr + 1;
2419
2420 if (sender_host_address != NULL)
2421 {
2422 s = string_cat(s, &size, &ptr, US" [", 2);
2423 s = string_cat(s, &size, &ptr, sender_host_address,
2424 Ustrlen(sender_host_address));
2425 s = string_cat(s, &size, &ptr, US"]", 1);
2426 }
2427
2428 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2429
2430 /* If we received EHLO, we must create a multiline response which includes
2431 the functions supported. */
2432
2433 if (esmtp)
2434 {
2435 s[3] = '-';
2436
2437 /* I'm not entirely happy with this, as an MTA is supposed to check
2438 that it has enough room to accept a message of maximum size before
2439 it sends this. However, there seems little point in not sending it.
2440 The actual size check happens later at MAIL FROM time. By postponing it
2441 till then, VRFY and EXPN can be used after EHLO when space is short. */
2442
2443 if (thismessage_size_limit > 0)
2444 {
2445 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2446 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2447 }
2448 else
2449 {
2450 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2451 }
2452
2453 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2454 clean; if it has an 8-bit character in its hand, it just sends it. It
2455 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2456 However, some users want this option simply in order to stop MUAs
2457 mangling messages that contain top-bit-set characters. It is therefore
2458 provided as an option. */
2459
2460 if (accept_8bitmime)
2461 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2462
2463 /* Advertise ETRN if there's an ACL checking whether a host is
2464 permitted to issue it; a check is made when any host actually tries. */
2465
2466 if (acl_smtp_etrn != NULL)
2467 {
2468 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2469 }
2470
2471 /* Advertise EXPN if there's an ACL checking whether a host is
2472 permitted to issue it; a check is made when any host actually tries. */
2473
2474 if (acl_smtp_expn != NULL)
2475 {
2476 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2477 }
2478
2479 /* Exim is quite happy with pipelining, so let the other end know that
2480 it is safe to use it, unless advertising is disabled. */
2481
2482 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2483 {
2484 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2485 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2486 pipelining_advertised = TRUE;
2487 }
2488
2489 /* If any server authentication mechanisms are configured, advertise
2490 them if the current host is in auth_advertise_hosts. The problem with
2491 advertising always is that some clients then require users to
2492 authenticate (and aren't configurable otherwise) even though it may not
2493 be necessary (e.g. if the host is in host_accept_relay).
2494
2495 RFC 2222 states that SASL mechanism names contain only upper case
2496 letters, so output the names in upper case, though we actually recognize
2497 them in either case in the AUTH command. */
2498
2499 if (auths != NULL)
2500 {
2501 if (verify_check_host(&auth_advertise_hosts) == OK)
2502 {
2503 auth_instance *au;
2504 BOOL first = TRUE;
2505 for (au = auths; au != NULL; au = au->next)
2506 {
2507 if (au->server && (au->advertise_condition == NULL ||
2508 expand_check_condition(au->advertise_condition, au->name,
2509 US"authenticator")))
2510 {
2511 int saveptr;
2512 if (first)
2513 {
2514 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2515 first = FALSE;
2516 auth_advertised = TRUE;
2517 }
2518 saveptr = ptr;
2519 s = string_cat(s, &size, &ptr, US" ", 1);
2520 s = string_cat(s, &size, &ptr, au->public_name,
2521 Ustrlen(au->public_name));
2522 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2523 au->advertised = TRUE;
2524 }
2525 else au->advertised = FALSE;
2526 }
2527 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2528 }
2529 }
2530
2531 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2532 if it has been included in the binary, and the host matches
2533 tls_advertise_hosts. We must *not* advertise if we are already in a
2534 secure connection. */
2535
2536 #ifdef SUPPORT_TLS
2537 if (tls_active < 0 &&
2538 verify_check_host(&tls_advertise_hosts) != FAIL)
2539 {
2540 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2541 tls_advertised = TRUE;
2542 }
2543 #endif
2544
2545 /* Finish off the multiline reply with one that is always available. */
2546
2547 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2548 }
2549
2550 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2551 has been seen. */
2552
2553 s[ptr] = 0;
2554
2555 #ifdef SUPPORT_TLS
2556 if (tls_active >= 0) (void)tls_write(s, ptr); else
2557 #endif
2558
2559 fwrite(s, 1, ptr, smtp_out);
2560 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2561 helo_seen = TRUE;
2562 break; /* HELO/EHLO */
2563
2564
2565 /* The MAIL command requires an address as an operand. All we do
2566 here is to parse it for syntactic correctness. The form "<>" is
2567 a special case which converts into an empty string. The start/end
2568 pointers in the original are not used further for this address, as
2569 it is the canonical extracted address which is all that is kept. */
2570
2571 case MAIL_CMD:
2572 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2573 was_rej_mail = TRUE; /* Reset if accepted */
2574
2575 if (helo_required && !helo_seen)
2576 {
2577 smtp_printf("503 HELO or EHLO required\r\n");
2578 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2579 "HELO/EHLO given", host_and_ident(FALSE));
2580 break;
2581 }
2582
2583 if (sender_address != NULL)
2584 {
2585 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2586 US"sender already given");
2587 break;
2588 }
2589
2590 if (smtp_data[0] == 0)
2591 {
2592 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2593 US"MAIL must have an address operand");
2594 break;
2595 }
2596
2597 /* Check to see if the limit for messages per connection would be
2598 exceeded by accepting further messages. */
2599
2600 if (smtp_accept_max_per_connection > 0 &&
2601 smtp_mailcmd_count > smtp_accept_max_per_connection)
2602 {
2603 smtp_printf("421 too many messages in this connection\r\n");
2604 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2605 "messages in one connection", host_and_ident(TRUE));
2606 break;
2607 }
2608
2609 /* Reset for start of message - even if this is going to fail, we
2610 obviously need to throw away any previous data. */
2611
2612 smtp_reset(reset_point);
2613 toomany = FALSE;
2614 sender_data = recipient_data = NULL;
2615
2616 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2617
2618 if (esmtp) for(;;)
2619 {
2620 uschar *name, *value, *end;
2621 unsigned long int size;
2622
2623 if (!extract_option(&name, &value)) break;
2624
2625 /* Handle SIZE= by reading the value. We don't do the check till later,
2626 in order to be able to log the sender address on failure. */
2627
2628 if (strcmpic(name, US"SIZE") == 0 &&
2629 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2630 {
2631 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2632 size = INT_MAX;
2633 message_size = (int)size;
2634 }
2635
2636 /* If this session was initiated with EHLO and accept_8bitmime is set,
2637 Exim will have indicated that it supports the BODY=8BITMIME option. In
2638 fact, it does not support this according to the RFCs, in that it does not
2639 take any special action for forwarding messages containing 8-bit
2640 characters. That is why accept_8bitmime is not the default setting, but
2641 some sites want the action that is provided. We recognize both "8BITMIME"
2642 and "7BIT" as body types, but take no action. */
2643
2644 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2645 (strcmpic(value, US"8BITMIME") == 0 ||
2646 strcmpic(value, US"7BIT") == 0)) {}
2647
2648 /* Handle the AUTH extension. If the value given is not "<>" and either
2649 the ACL says "yes" or there is no ACL but the sending host is
2650 authenticated, we set it up as the authenticated sender. However, if the
2651 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2652 the condition is met. The value of AUTH is an xtext, which means that +,
2653 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2654 coding. */
2655
2656 else if (strcmpic(name, US"AUTH") == 0)
2657 {
2658 if (Ustrcmp(value, "<>") != 0)
2659 {
2660 int rc;
2661 uschar *ignore_msg;
2662
2663 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2664 {
2665 /* Put back terminator overrides for error message */
2666 name[-1] = ' ';
2667 value[-1] = '=';
2668 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2669 US"invalid data for AUTH");
2670 goto COMMAND_LOOP;
2671 }
2672
2673 if (acl_smtp_mailauth == NULL)
2674 {
2675 ignore_msg = US"client not authenticated";
2676 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2677 }
2678 else
2679 {
2680 ignore_msg = US"rejected by ACL";
2681 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2682 &user_msg, &log_msg);
2683 }
2684
2685 switch (rc)
2686 {
2687 case OK:
2688 if (authenticated_by == NULL ||
2689 authenticated_by->mail_auth_condition == NULL ||
2690 expand_check_condition(authenticated_by->mail_auth_condition,
2691 authenticated_by->name, US"authenticator"))
2692 break; /* Accept the AUTH */
2693
2694 ignore_msg = US"server_mail_auth_condition failed";
2695 if (authenticated_id != NULL)
2696 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2697 ignore_msg, authenticated_id);
2698
2699 /* Fall through */
2700
2701 case FAIL:
2702 authenticated_sender = NULL;
2703 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2704 value, host_and_ident(TRUE), ignore_msg);
2705 break;
2706
2707 /* Should only get DEFER or ERROR here. Put back terminator
2708 overrides for error message */
2709
2710 default:
2711 name[-1] = ' ';
2712 value[-1] = '=';
2713 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2714 log_msg);
2715 goto COMMAND_LOOP;
2716 }
2717 }
2718 }
2719
2720 /* Unknown option. Stick back the terminator characters and break
2721 the loop. An error for a malformed address will occur. */
2722
2723 else
2724 {
2725 name[-1] = ' ';
2726 value[-1] = '=';
2727 break;
2728 }
2729 }
2730
2731 /* If we have passed the threshold for rate limiting, apply the current
2732 delay, and update it for next time, provided this is a limited host. */
2733
2734 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2735 verify_check_host(&smtp_ratelimit_hosts) == OK)
2736 {
2737 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2738 smtp_delay_mail/1000.0);
2739 millisleep((int)smtp_delay_mail);
2740 smtp_delay_mail *= smtp_rlm_factor;
2741 if (smtp_delay_mail > (double)smtp_rlm_limit)
2742 smtp_delay_mail = (double)smtp_rlm_limit;
2743 }
2744
2745 /* Now extract the address, first applying any SMTP-time rewriting. The
2746 TRUE flag allows "<>" as a sender address. */
2747
2748 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2749 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2750 global_rewrite_rules) : smtp_data;
2751
2752 /* rfc821_domains = TRUE; << no longer needed */
2753 raw_sender =
2754 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2755 TRUE);
2756 /* rfc821_domains = FALSE; << no longer needed */
2757
2758 if (raw_sender == NULL)
2759 {
2760 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2761 break;
2762 }
2763
2764 sender_address = raw_sender;
2765
2766 /* If there is a configured size limit for mail, check that this message
2767 doesn't exceed it. The check is postponed to this point so that the sender
2768 can be logged. */
2769
2770 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2771 {
2772 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2773 log_write(L_size_reject,
2774 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2775 "message too big: size%s=%d max=%d",
2776 sender_address,
2777 host_and_ident(TRUE),
2778 (message_size == INT_MAX)? ">" : "",
2779 message_size,
2780 thismessage_size_limit);
2781 sender_address = NULL;
2782 break;
2783 }
2784
2785 /* Check there is enough space on the disk unless configured not to.
2786 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2787 plus the current message - i.e. we accept the message only if it won't
2788 reduce the space below the threshold. Add 5000 to the size to allow for
2789 overheads such as the Received: line and storing of recipients, etc.
2790 By putting the check here, even when SIZE is not given, it allow VRFY
2791 and EXPN etc. to be used when space is short. */
2792
2793 if (!receive_check_fs(
2794 (smtp_check_spool_space && message_size >= 0)?
2795 message_size + 5000 : 0))
2796 {
2797 smtp_printf("452 Space shortage, please try later\r\n");
2798 sender_address = NULL;
2799 break;
2800 }
2801
2802 /* If sender_address is unqualified, reject it, unless this is a locally
2803 generated message, or the sending host or net is permitted to send
2804 unqualified addresses - typically local machines behaving as MUAs -
2805 in which case just qualify the address. The flag is set above at the start
2806 of the SMTP connection. */
2807
2808 if (sender_domain == 0 && sender_address[0] != 0)
2809 {
2810 if (allow_unqualified_sender)
2811 {
2812 sender_domain = Ustrlen(sender_address) + 1;
2813 sender_address = rewrite_address_qualify(sender_address, FALSE);
2814 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2815 raw_sender);
2816 }
2817 else
2818 {
2819 smtp_printf("501 %s: sender address must contain a domain\r\n",
2820 smtp_data);
2821 log_write(L_smtp_syntax_error,
2822 LOG_MAIN|LOG_REJECT,
2823 "unqualified sender rejected: <%s> %s%s",
2824 raw_sender,
2825 host_and_ident(TRUE),
2826 host_lookup_msg);
2827 sender_address = NULL;
2828 break;
2829 }
2830 }
2831
2832 /* Apply an ACL check if one is defined, before responding */
2833
2834 rc = (acl_smtp_mail == NULL)? OK :
2835 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2836
2837 if (rc == OK || rc == DISCARD)
2838 {
2839 smtp_printf("250 OK\r\n");
2840 smtp_delay_rcpt = smtp_rlr_base;
2841 recipients_discarded = (rc == DISCARD);
2842 was_rej_mail = FALSE;
2843 }
2844
2845 else
2846 {
2847 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2848 sender_address = NULL;
2849 }
2850 break;
2851
2852
2853 /* The RCPT command requires an address as an operand. All we do
2854 here is to parse it for syntactic correctness. There may be any number
2855 of RCPT commands, specifying multiple senders. We build them all into
2856 a data structure that is in argc/argv format. The start/end values
2857 given by parse_extract_address are not used, as we keep only the
2858 extracted address. */
2859
2860 case RCPT_CMD:
2861 rcpt_count++;
2862 was_rcpt = TRUE;
2863
2864 /* There must be a sender address; if the sender was rejected and
2865 pipelining was advertised, we assume the client was pipelining, and do not
2866 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2867 get the same treatment. */
2868
2869 if (sender_address == NULL)
2870 {
2871 if (pipelining_advertised && last_was_rej_mail)
2872 {
2873 smtp_printf("503 sender not yet given\r\n");
2874 was_rej_mail = TRUE;
2875 }
2876 else
2877 {
2878 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2879 US"sender not yet given");
2880 was_rcpt = FALSE; /* Not a valid RCPT */
2881 }
2882 rcpt_fail_count++;
2883 break;
2884 }
2885
2886 /* Check for an operand */
2887
2888 if (smtp_data[0] == 0)
2889 {
2890 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2891 US"RCPT must have an address operand");
2892 rcpt_fail_count++;
2893 break;
2894 }
2895
2896 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2897 as a recipient address */
2898
2899 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2900 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2901 global_rewrite_rules) : smtp_data;
2902
2903 /* rfc821_domains = TRUE; << no longer needed */
2904 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2905 &recipient_domain, FALSE);
2906 /* rfc821_domains = FALSE; << no longer needed */
2907
2908 if (recipient == NULL)
2909 {
2910 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2911 rcpt_fail_count++;
2912 break;
2913 }
2914
2915 /* If the recipient address is unqualified, reject it, unless this is a
2916 locally generated message. However, unqualified addresses are permitted
2917 from a configured list of hosts and nets - typically when behaving as
2918 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2919 really. The flag is set at the start of the SMTP connection.
2920
2921 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2922 assumed this meant "reserved local part", but the revision of RFC 821 and
2923 friends now makes it absolutely clear that it means *mailbox*. Consequently
2924 we must always qualify this address, regardless. */
2925
2926 if (recipient_domain == 0)
2927 {
2928 if (allow_unqualified_recipient ||
2929 strcmpic(recipient, US"postmaster") == 0)
2930 {
2931 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2932 recipient);
2933 recipient_domain = Ustrlen(recipient) + 1;
2934 recipient = rewrite_address_qualify(recipient, TRUE);
2935 }
2936 else
2937 {
2938 rcpt_fail_count++;
2939 smtp_printf("501 %s: recipient address must contain a domain\r\n",
2940 smtp_data);
2941 log_write(L_smtp_syntax_error,
2942 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
2943 "<%s> %s%s", recipient, host_and_ident(TRUE),
2944 host_lookup_msg);
2945 break;
2946 }
2947 }
2948
2949 /* Check maximum allowed */
2950
2951 if (rcpt_count > recipients_max && recipients_max > 0)
2952 {
2953 if (recipients_max_reject)
2954 {
2955 rcpt_fail_count++;
2956 smtp_printf("552 too many recipients\r\n");
2957 if (!toomany)
2958 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
2959 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
2960 }
2961 else
2962 {
2963 rcpt_defer_count++;
2964 smtp_printf("452 too many recipients\r\n");
2965 if (!toomany)
2966 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
2967 "temporarily rejected: sender=<%s> %s", sender_address,
2968 host_and_ident(TRUE));
2969 }
2970
2971 toomany = TRUE;
2972 break;
2973 }
2974
2975 /* If we have passed the threshold for rate limiting, apply the current
2976 delay, and update it for next time, provided this is a limited host. */
2977
2978 if (rcpt_count > smtp_rlr_threshold &&
2979 verify_check_host(&smtp_ratelimit_hosts) == OK)
2980 {
2981 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
2982 smtp_delay_rcpt/1000.0);
2983 millisleep((int)smtp_delay_rcpt);
2984 smtp_delay_rcpt *= smtp_rlr_factor;
2985 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
2986 smtp_delay_rcpt = (double)smtp_rlr_limit;
2987 }
2988
2989 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
2990 for them. Otherwise, check the access control list for this recipient. */
2991
2992 rc = recipients_discarded? DISCARD :
2993 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
2994
2995 /* The ACL was happy */
2996
2997 if (rc == OK)
2998 {
2999 smtp_printf("250 Accepted\r\n");
3000 receive_add_recipient(recipient, -1);
3001 }
3002
3003 /* The recipient was discarded */
3004
3005 else if (rc == DISCARD)
3006 {
3007 smtp_printf("250 Accepted\r\n");
3008 rcpt_fail_count++;
3009 discarded = TRUE;
3010 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3011 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3012 (sender_address_unrewritten != NULL)?
3013 sender_address_unrewritten : sender_address,
3014 smtp_data, recipients_discarded? "MAIL" : "RCPT",
3015 (log_msg == NULL)? US"" : US": ",
3016 (log_msg == NULL)? US"" : log_msg);
3017 }
3018
3019 /* Either the ACL failed the address, or it was deferred. */
3020
3021 else
3022 {
3023 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3024 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3025 }
3026 break;
3027
3028
3029 /* The DATA command is legal only if it follows successful MAIL FROM
3030 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3031 not counted as a protocol error if it follows RCPT (which must have been
3032 rejected if there are no recipients.) This function is complete when a
3033 valid DATA command is encountered.
3034
3035 Note concerning the code used: RFC 2821 says this:
3036
3037 - If there was no MAIL, or no RCPT, command, or all such commands
3038 were rejected, the server MAY return a "command out of sequence"
3039 (503) or "no valid recipients" (554) reply in response to the
3040 DATA command.
3041
3042 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3043 because it is the same whether pipelining is in use or not. */
3044
3045 case DATA_CMD:
3046 if (!discarded && recipients_count <= 0)
3047 {
3048 if (pipelining_advertised && last_was_rcpt)
3049 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3050 else
3051 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3052 US"valid RCPT command must precede DATA");
3053 break;
3054 }
3055
3056 if (toomany && recipients_max_reject)
3057 {
3058 sender_address = NULL; /* This will allow a new MAIL without RSET */
3059 sender_address_unrewritten = NULL;
3060 smtp_printf("554 Too many recipients\r\n");
3061 break;
3062 }
3063
3064 if (acl_smtp_predata == NULL) rc = OK; else
3065 {
3066 enable_dollar_recipients = TRUE;
3067 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3068 &log_msg);
3069 enable_dollar_recipients = FALSE;
3070 }
3071
3072 if (rc == OK)
3073 {
3074 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3075 done = 3;
3076 message_ended = END_NOTENDED; /* Indicate in middle of data */
3077 }
3078
3079 /* Either the ACL failed the address, or it was deferred. */
3080
3081 else
3082 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3083
3084 break;
3085
3086
3087 case VRFY_CMD:
3088 rc = acl_check(ACL_WHERE_VRFY, smtp_data, acl_smtp_vrfy, &user_msg,
3089 &log_msg);
3090 if (rc != OK)
3091 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3092 else
3093 {
3094 uschar *address;
3095 uschar *s = NULL;
3096
3097 /* rfc821_domains = TRUE; << no longer needed */
3098 address = parse_extract_address(smtp_data, &errmess, &start, &end,
3099 &recipient_domain, FALSE);
3100 /* rfc821_domains = FALSE; << no longer needed */
3101
3102 if (address == NULL)
3103 s = string_sprintf("501 %s", errmess);
3104 else
3105 {
3106 address_item *addr = deliver_make_addr(address, FALSE);
3107 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3108 -1, -1, NULL, NULL, NULL))
3109 {
3110 case OK:
3111 s = string_sprintf("250 <%s> is deliverable", address);
3112 break;
3113
3114 case DEFER:
3115 s = (addr->message != NULL)?
3116 string_sprintf("451 <%s> %s", address, addr->message) :
3117 string_sprintf("451 Cannot resolve <%s> at this time", address);
3118 break;
3119
3120 case FAIL:
3121 s = (addr->message != NULL)?
3122 string_sprintf("550 <%s> %s", address, addr->message) :
3123 string_sprintf("550 <%s> is not deliverable", address);
3124 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3125 smtp_data, host_and_ident(TRUE));
3126 break;
3127 }
3128 }
3129
3130 smtp_printf("%s\r\n", s);
3131 }
3132 break;
3133
3134
3135 case EXPN_CMD:
3136 rc = acl_check(ACL_WHERE_EXPN, smtp_data, acl_smtp_expn, &user_msg,
3137 &log_msg);
3138 if (rc != OK)
3139 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3140 else
3141 {
3142 BOOL save_log_testing_mode = log_testing_mode;
3143 address_test_mode = log_testing_mode = TRUE;
3144 (void) verify_address(deliver_make_addr(smtp_data, FALSE), smtp_out,
3145 vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1, NULL, NULL,
3146 NULL);
3147 address_test_mode = FALSE;
3148 log_testing_mode = save_log_testing_mode; /* true for -bh */
3149 }
3150 break;
3151
3152
3153 #ifdef SUPPORT_TLS
3154
3155 case STARTTLS_CMD:
3156 if (!tls_advertised)
3157 {
3158 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3159 US"STARTTLS command used when not advertised");
3160 break;
3161 }
3162
3163 /* Apply an ACL check if one is defined */
3164
3165 if (acl_smtp_starttls != NULL)
3166 {
3167 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3168 &log_msg);
3169 if (rc != OK)
3170 {
3171 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3172 break;
3173 }
3174 }
3175
3176 /* RFC 2487 is not clear on when this command may be sent, though it
3177 does state that all information previously obtained from the client
3178 must be discarded if a TLS session is started. It seems reasonble to
3179 do an implied RSET when STARTTLS is received. */
3180
3181 incomplete_transaction_log(US"STARTTLS");
3182 smtp_reset(reset_point);
3183 toomany = FALSE;
3184 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3185
3186 /* Attempt to start up a TLS session, and if successful, discard all
3187 knowledge that was obtained previously. At least, that's what the RFC says,
3188 and that's what happens by default. However, in order to work round YAEB,
3189 there is an option to remember the esmtp state. Sigh.
3190
3191 We must allow for an extra EHLO command and an extra AUTH command after
3192 STARTTLS that don't add to the nonmail command count. */
3193
3194 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3195 {
3196 if (!tls_remember_esmtp)
3197 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3198 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3199 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3200 if (sender_helo_name != NULL)
3201 {
3202 store_free(sender_helo_name);
3203 sender_helo_name = NULL;
3204 host_build_sender_fullhost(); /* Rebuild */
3205 set_process_info("handling incoming TLS connection from %s",
3206 host_and_ident(FALSE));
3207 }
3208 received_protocol = (esmtp?
3209 protocols[pextend + pcrpted +
3210 ((sender_host_authenticated != NULL)? pauthed : 0)]
3211 :
3212 protocols[pnormal + pcrpted])
3213 +
3214 ((sender_host_address != NULL)? pnlocal : 0);
3215
3216 sender_host_authenticated = NULL;
3217 authenticated_id = NULL;
3218 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3219 DEBUG(D_tls) debug_printf("TLS active\n");
3220 break; /* Successful STARTTLS */
3221 }
3222
3223 /* Some local configuration problem was discovered before actually trying
3224 to do a TLS handshake; give a temporary error. */
3225
3226 else if (rc == DEFER)
3227 {
3228 smtp_printf("454 TLS currently unavailable\r\n");
3229 break;
3230 }
3231
3232 /* Hard failure. Reject everything except QUIT or closed connection. One
3233 cause for failure is a nested STARTTLS, in which case tls_active remains
3234 set, but we must still reject all incoming commands. */
3235
3236 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3237 while (done <= 0)
3238 {
3239 switch(smtp_read_command(FALSE))
3240 {
3241 case EOF_CMD:
3242 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3243 smtp_get_connection_info());
3244 done = 2;
3245 break;
3246
3247 case QUIT_CMD:
3248 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3249 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3250 smtp_get_connection_info());
3251 done = 2;
3252 break;
3253
3254 default:
3255 smtp_printf("554 Security failure\r\n");
3256 break;
3257 }
3258 }
3259 tls_close(TRUE);
3260 break;
3261 #endif
3262
3263
3264 /* The ACL for QUIT is provided for gathering statistical information or
3265 similar; it does not affect the response code, but it can supply a custom
3266 message. */
3267
3268 case QUIT_CMD:
3269 incomplete_transaction_log(US"QUIT");
3270
3271 if (acl_smtp_quit != NULL)
3272 {
3273 rc = acl_check(ACL_WHERE_QUIT, US"", acl_smtp_quit,&user_msg,&log_msg);
3274 if (rc == ERROR)
3275 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3276 log_msg);
3277 }
3278 else user_msg = NULL;
3279
3280 if (user_msg == NULL)
3281 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3282 else
3283 smtp_printf("221 %s\r\n", user_msg);
3284
3285 #ifdef SUPPORT_TLS
3286 tls_close(TRUE);
3287 #endif
3288
3289 done = 2;
3290 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3291 smtp_get_connection_info());
3292 break;
3293
3294
3295 case RSET_CMD:
3296 incomplete_transaction_log(US"RSET");
3297 smtp_reset(reset_point);
3298 toomany = FALSE;
3299 smtp_printf("250 Reset OK\r\n");
3300 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3301 break;
3302
3303
3304 case NOOP_CMD:
3305 smtp_printf("250 OK\r\n");
3306 break;
3307
3308
3309 /* Show ETRN/EXPN/VRFY if there's
3310 an ACL for checking hosts; if actually used, a check will be done for
3311 permitted hosts. */
3312
3313 case HELP_CMD:
3314 smtp_printf("214-Commands supported:\r\n");
3315 {
3316 uschar buffer[256];
3317 buffer[0] = 0;
3318 Ustrcat(buffer, " AUTH");
3319 #ifdef SUPPORT_TLS
3320 Ustrcat(buffer, " STARTTLS");
3321 #endif
3322 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3323 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3324 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3325 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3326 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3327 smtp_printf("214%s\r\n", buffer);
3328 }
3329 break;
3330
3331
3332 case EOF_CMD:
3333 incomplete_transaction_log(US"connection lost");
3334 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3335
3336 /* Don't log by default unless in the middle of a message, as some mailers
3337 just drop the call rather than sending QUIT, and it clutters up the logs.
3338 */
3339
3340 if (sender_address != NULL || recipients_count > 0)
3341 log_write(L_lost_incoming_connection,
3342 LOG_MAIN,
3343 "unexpected %s while reading SMTP command from %s%s",
3344 sender_host_unknown? "EOF" : "disconnection",
3345 host_and_ident(FALSE), smtp_read_error);
3346
3347 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3348 smtp_get_connection_info(), smtp_read_error);
3349
3350 done = 1;
3351 break;
3352
3353
3354 case ETRN_CMD:
3355 if (sender_address != NULL)
3356 {
3357 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3358 US"ETRN is not permitted inside a transaction");
3359 break;
3360 }
3361
3362 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_data,
3363 host_and_ident(FALSE));
3364
3365 rc = acl_check(ACL_WHERE_ETRN, smtp_data, acl_smtp_etrn, &user_msg,
3366 &log_msg);
3367 if (rc != OK)
3368 {
3369 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3370 break;
3371 }
3372
3373 /* Compute the serialization key for this command. */
3374
3375 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_data);
3376
3377 /* If a command has been specified for running as a result of ETRN, we
3378 permit any argument to ETRN. If not, only the # standard form is permitted,
3379 since that is strictly the only kind of ETRN that can be implemented
3380 according to the RFC. */
3381
3382 if (smtp_etrn_command != NULL)
3383 {
3384 uschar *error;
3385 BOOL rc;
3386 etrn_command = smtp_etrn_command;
3387 deliver_domain = smtp_data;
3388 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3389 US"ETRN processing", &error);
3390 deliver_domain = NULL;
3391 if (!rc)
3392 {
3393 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3394 error);
3395 smtp_printf("458 Internal failure\r\n");
3396 break;
3397 }
3398 }
3399
3400 /* Else set up to call Exim with the -R option. */
3401
3402 else
3403 {
3404 if (*smtp_data++ != '#')
3405 {
3406 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3407 US"argument must begin with #");
3408 break;
3409 }
3410 etrn_command = US"exim -R";
3411 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3412 smtp_data);
3413 }
3414
3415 /* If we are host-testing, don't actually do anything. */
3416
3417 if (host_checking)
3418 {
3419 HDEBUG(D_any)
3420 {
3421 debug_printf("ETRN command is: %s\n", etrn_command);
3422 debug_printf("ETRN command execution skipped\n");
3423 }
3424 smtp_printf("250 OK\r\n");
3425 break;
3426 }
3427
3428
3429 /* If ETRN queue runs are to be serialized, check the database to
3430 ensure one isn't already running. */
3431
3432 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3433 {
3434 smtp_printf("458 Already processing %s\r\n", smtp_data);
3435 break;
3436 }
3437
3438 /* Fork a child process and run the command. We don't want to have to
3439 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3440 forking. It should be set that way anyway for external incoming SMTP,
3441 but we save and restore to be tidy. If serialization is required, we
3442 actually run the command in yet another process, so we can wait for it
3443 to complete and then remove the serialization lock. */
3444
3445 oldsignal = signal(SIGCHLD, SIG_IGN);
3446
3447 if ((pid = fork()) == 0)
3448 {
3449 smtp_input = FALSE; /* This process is not associated with the */
3450 fclose(smtp_in); /* SMTP call any more. */
3451 fclose(smtp_out);
3452
3453 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3454
3455 /* If not serializing, do the exec right away. Otherwise, fork down
3456 into another process. */
3457
3458 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3459 {
3460 DEBUG(D_exec) debug_print_argv(argv);
3461 exim_nullstd(); /* Ensure std{in,out,err} exist */
3462 execv(CS argv[0], (char *const *)argv);
3463 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3464 etrn_command, strerror(errno));
3465 _exit(EXIT_FAILURE); /* paranoia */
3466 }
3467
3468 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3469 is, we are in the first subprocess, after forking again. All we can do
3470 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3471 complete, before removing the serialization. */
3472
3473 if (pid < 0)
3474 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3475 "failed: %s", strerror(errno));
3476 else
3477 {
3478 int status;
3479 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3480 (int)pid);
3481 (void)wait(&status);
3482 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3483 (int)pid);
3484 }
3485
3486 enq_end(etrn_serialize_key);
3487 _exit(EXIT_SUCCESS);
3488 }
3489
3490 /* Back in the top level SMTP process. Check that we started a subprocess
3491 and restore the signal state. */
3492
3493 if (pid < 0)
3494 {
3495 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3496 strerror(errno));
3497 smtp_printf("458 Unable to fork process\r\n");
3498 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3499 }
3500 else smtp_printf("250 OK\r\n");
3501
3502 signal(SIGCHLD, oldsignal);
3503 break;
3504
3505
3506 case BADARG_CMD