Remove "violation:" from synchronization error message.
[exim.git] / src / src / smtp_in.c
1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.21 2005/08/02 08:25:45 ph10 Exp $ */
2
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
6
7 /* Copyright (c) University of Cambridge 1995 - 2005 */
8 /* See the file NOTICE for conditions of use and distribution. */
9
10 /* Functions for handling an incoming SMTP call. */
11
12
13 #include "exim.h"
14
15
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
19
20 #ifdef USE_TCP_WRAPPERS
21
22 #if HAVE_IPV6
23 #define EXIM_HAVE_IPV6
24 #endif
25 #undef HAVE_IPV6
26 #include <tcpd.h>
27 #undef HAVE_IPV6
28 #ifdef EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
30 #endif
31
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
34 #endif
35
36
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. */
41
42 #define cmd_buffer_size 2048
43
44 /* Size of buffer for reading SMTP incoming packets */
45
46 #define in_buffer_size 8192
47
48 /* Structure for SMTP command list */
49
50 typedef struct {
51 char *name;
52 int len;
53 short int cmd;
54 short int has_arg;
55 short int is_mail_cmd;
56 } smtp_cmd_list;
57
58 /* Codes for identifying commands. We order them so that those that come first
59 are those for which synchronization is always required. Checking this can help
60 block some spam. */
61
62 enum {
63 /* These commands are required to be synchronized, i.e. to be the last in a
64 block of commands when pipelining. */
65
66 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
67 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
68 ETRN_CMD, /* This by analogy with TURN from the RFC */
69 STARTTLS_CMD, /* Required by the STARTTLS RFC */
70
71 /* This is a dummy to identify the non-sync commands when pipelining */
72
73 NON_SYNC_CMD_PIPELINING,
74
75 /* These commands need not be synchronized when pipelining */
76
77 MAIL_CMD, RCPT_CMD, RSET_CMD,
78
79 /* This is a dummy to identify the non-sync commands when not pipelining */
80
81 NON_SYNC_CMD_NON_PIPELINING,
82
83 /* I have been unable to find a statement about the use of pipelining
84 with AUTH, so to be on the safe side it is here, though I kind of feel
85 it should be up there with the synchronized commands. */
86
87 AUTH_CMD,
88
89 /* I'm not sure about these, but I don't think they matter. */
90
91 QUIT_CMD, HELP_CMD,
92
93 /* These are specials that don't correspond to actual commands */
94
95 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
96 TOO_MANY_NONMAIL_CMD };
97
98
99
100 /*************************************************
101 * Local static variables *
102 *************************************************/
103
104 static auth_instance *authenticated_by;
105 static BOOL auth_advertised;
106 #ifdef SUPPORT_TLS
107 static BOOL tls_advertised;
108 #endif
109 static BOOL esmtp;
110 static BOOL helo_required = FALSE;
111 static BOOL helo_verify = FALSE;
112 static BOOL helo_seen;
113 static BOOL helo_accept_junk;
114 static BOOL count_nonmail;
115 static BOOL pipelining_advertised;
116 static int nonmail_command_count;
117 static int synprot_error_count;
118 static int unknown_command_count;
119 static int sync_cmd_limit;
120 static int smtp_write_error = 0;
121
122 static uschar *smtp_data;
123
124 static uschar *cmd_buffer;
125
126 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
127 final fields of all except AUTH are forced TRUE at the start of a new message
128 setup, to allow one of each between messages that is not counted as a nonmail
129 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
130 allow a new EHLO after starting up TLS.
131
132 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
133 counted. However, the flag is changed when AUTH is received, so that multiple
134 failing AUTHs will eventually hit the limit. After a successful AUTH, another
135 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
136 forced TRUE, to allow for the re-authentication that can happen at that point.
137
138 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
139 count of non-mail commands and possibly provoke an error. */
140
141 static smtp_cmd_list cmd_list[] = {
142 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
143 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
144 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
145 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
146 #ifdef SUPPORT_TLS
147 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
148 #endif
149
150 /* If you change anything above here, also fix the definitions below. */
151
152 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
153 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
154 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
155 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
156 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
157 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
158 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
159 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
160 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
161 };
162
163 static smtp_cmd_list *cmd_list_end =
164 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
165
166 #define CMD_LIST_RSET 0
167 #define CMD_LIST_HELO 1
168 #define CMD_LIST_EHLO 2
169 #define CMD_LIST_AUTH 3
170 #define CMD_LIST_STARTTLS 4
171
172 static uschar *protocols[] = {
173 US"local-smtp", /* HELO */
174 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
175 US"local-esmtp", /* EHLO */
176 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
177 US"local-esmtpa", /* EHLO->AUTH */
178 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
179 };
180
181 #define pnormal 0
182 #define pextend 2
183 #define pcrpted 1 /* added to pextend or pnormal */
184 #define pauthed 2 /* added to pextend */
185 #define pnlocal 6 /* offset to remove "local" */
186
187 /* When reading SMTP from a remote host, we have to use our own versions of the
188 C input-reading functions, in order to be able to flush the SMTP output only
189 when about to read more data from the socket. This is the only way to get
190 optimal performance when the client is using pipelining. Flushing for every
191 command causes a separate packet and reply packet each time; saving all the
192 responses up (when pipelining) combines them into one packet and one response.
193
194 For simplicity, these functions are used for *all* SMTP input, not only when
195 receiving over a socket. However, after setting up a secure socket (SSL), input
196 is read via the OpenSSL library, and another set of functions is used instead
197 (see tls.c).
198
199 These functions are set in the receive_getc etc. variables and called with the
200 same interface as the C functions. However, since there can only ever be
201 one incoming SMTP call, we just use a single buffer and flags. There is no need
202 to implement a complicated private FILE-like structure.*/
203
204 static uschar *smtp_inbuffer;
205 static uschar *smtp_inptr;
206 static uschar *smtp_inend;
207 static int smtp_had_eof;
208 static int smtp_had_error;
209
210
211 /*************************************************
212 * SMTP version of getc() *
213 *************************************************/
214
215 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
216 it flushes the output, and refills the buffer, with a timeout. The signal
217 handler is set appropriately by the calling function. This function is not used
218 after a connection has negotated itself into an TLS/SSL state.
219
220 Arguments: none
221 Returns: the next character or EOF
222 */
223
224 int
225 smtp_getc(void)
226 {
227 if (smtp_inptr >= smtp_inend)
228 {
229 int rc, save_errno;
230 fflush(smtp_out);
231 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
232 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
233 save_errno = errno;
234 alarm(0);
235 if (rc <= 0)
236 {
237 /* Must put the error text in fixed store, because this might be during
238 header reading, where it releases unused store above the header. */
239 if (rc < 0)
240 {
241 smtp_had_error = save_errno;
242 smtp_read_error = string_copy_malloc(
243 string_sprintf(" (error: %s)", strerror(save_errno)));
244 }
245 else smtp_had_eof = 1;
246 return EOF;
247 }
248 smtp_inend = smtp_inbuffer + rc;
249 smtp_inptr = smtp_inbuffer;
250 }
251 return *smtp_inptr++;
252 }
253
254
255
256 /*************************************************
257 * SMTP version of ungetc() *
258 *************************************************/
259
260 /* Puts a character back in the input buffer. Only ever
261 called once.
262
263 Arguments:
264 ch the character
265
266 Returns: the character
267 */
268
269 int
270 smtp_ungetc(int ch)
271 {
272 *(--smtp_inptr) = ch;
273 return ch;
274 }
275
276
277
278
279 /*************************************************
280 * SMTP version of feof() *
281 *************************************************/
282
283 /* Tests for a previous EOF
284
285 Arguments: none
286 Returns: non-zero if the eof flag is set
287 */
288
289 int
290 smtp_feof(void)
291 {
292 return smtp_had_eof;
293 }
294
295
296
297
298 /*************************************************
299 * SMTP version of ferror() *
300 *************************************************/
301
302 /* Tests for a previous read error, and returns with errno
303 restored to what it was when the error was detected.
304
305 Arguments: none
306 Returns: non-zero if the error flag is set
307 */
308
309 int
310 smtp_ferror(void)
311 {
312 errno = smtp_had_error;
313 return smtp_had_error;
314 }
315
316
317
318
319 /*************************************************
320 * Write formatted string to SMTP channel *
321 *************************************************/
322
323 /* This is a separate function so that we don't have to repeat everything for
324 TLS support or debugging. It is global so that the daemon and the
325 authentication functions can use it. It does not return any error indication,
326 because major problems such as dropped connections won't show up till an output
327 flush for non-TLS connections. The smtp_fflush() function is available for
328 checking that: for convenience, TLS output errors are remembered here so that
329 they are also picked up later by smtp_fflush().
330
331 Arguments:
332 format format string
333 ... optional arguments
334
335 Returns: nothing
336 */
337
338 void
339 smtp_printf(char *format, ...)
340 {
341 va_list ap;
342
343 DEBUG(D_receive)
344 {
345 va_start(ap, format);
346 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
347 debug_printf("SMTP>> %s", big_buffer);
348 }
349
350 va_start(ap, format);
351
352 /* If in a TLS session we have to format the string, and then write it using a
353 TLS function. */
354
355 #ifdef SUPPORT_TLS
356 if (tls_active >= 0)
357 {
358 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
359 {
360 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
361 smtp_closedown(US"Unexpected error");
362 exim_exit(EXIT_FAILURE);
363 }
364 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
365 }
366 else
367 #endif
368
369 /* Otherwise, just use the standard library function. */
370
371 if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
372 va_end(ap);
373 }
374
375
376
377 /*************************************************
378 * Flush SMTP out and check for error *
379 *************************************************/
380
381 /* This function isn't currently used within Exim (it detects errors when it
382 tries to read the next SMTP input), but is available for use in local_scan().
383 For non-TLS connections, it flushes the output and checks for errors. For
384 TLS-connections, it checks for a previously-detected TLS write error.
385
386 Arguments: none
387 Returns: 0 for no error; -1 after an error
388 */
389
390 int
391 smtp_fflush(void)
392 {
393 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
394 return smtp_write_error;
395 }
396
397
398
399 /*************************************************
400 * SMTP command read timeout *
401 *************************************************/
402
403 /* Signal handler for timing out incoming SMTP commands. This attempts to
404 finish off tidily.
405
406 Argument: signal number (SIGALRM)
407 Returns: nothing
408 */
409
410 static void
411 command_timeout_handler(int sig)
412 {
413 sig = sig; /* Keep picky compilers happy */
414 log_write(L_lost_incoming_connection,
415 LOG_MAIN, "SMTP command timeout on%s connection from %s",
416 (tls_active >= 0)? " TLS" : "",
417 host_and_ident(FALSE));
418 if (smtp_batched_input)
419 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
420 smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
421 smtp_active_hostname);
422 mac_smtp_fflush();
423 exim_exit(EXIT_FAILURE);
424 }
425
426
427
428 /*************************************************
429 * SIGTERM received *
430 *************************************************/
431
432 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
433
434 Argument: signal number (SIGTERM)
435 Returns: nothing
436 */
437
438 static void
439 command_sigterm_handler(int sig)
440 {
441 sig = sig; /* Keep picky compilers happy */
442 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
443 if (smtp_batched_input)
444 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
445 smtp_printf("421 %s: Service not available - closing connection\r\n",
446 smtp_active_hostname);
447 exim_exit(EXIT_FAILURE);
448 }
449
450
451
452 /*************************************************
453 * Read one command line *
454 *************************************************/
455
456 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
457 There are sites that don't do this, and in any case internal SMTP probably
458 should check only for LF. Consequently, we check here for LF only. The line
459 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
460 an unknown command. The command is read into the static cmd_buffer.
461
462 The character reading routine sets up a timeout for each block actually read
463 from the input (which may contain more than one command). We set up a special
464 signal handler that closes down the session on a timeout. Control does not
465 return when it runs.
466
467 Arguments:
468 check_sync if TRUE, check synchronization rules if global option is TRUE
469
470 Returns: a code identifying the command (enumerated above)
471 */
472
473 static int
474 smtp_read_command(BOOL check_sync)
475 {
476 int c;
477 int ptr = 0;
478 smtp_cmd_list *p;
479 BOOL hadnull = FALSE;
480
481 os_non_restarting_signal(SIGALRM, command_timeout_handler);
482
483 while ((c = (receive_getc)()) != '\n' && c != EOF)
484 {
485 if (ptr >= cmd_buffer_size)
486 {
487 os_non_restarting_signal(SIGALRM, sigalrm_handler);
488 return OTHER_CMD;
489 }
490 if (c == 0)
491 {
492 hadnull = TRUE;
493 c = '?';
494 }
495 cmd_buffer[ptr++] = c;
496 }
497
498 receive_linecount++; /* For BSMTP errors */
499 os_non_restarting_signal(SIGALRM, sigalrm_handler);
500
501 /* If hit end of file, return pseudo EOF command. Whether we have a
502 part-line already read doesn't matter, since this is an error state. */
503
504 if (c == EOF) return EOF_CMD;
505
506 /* Remove any CR and white space at the end of the line, and terminate the
507 string. */
508
509 while (ptr > 0 && isspace(cmd_buffer[ptr-1])) ptr--;
510 cmd_buffer[ptr] = 0;
511
512 DEBUG(D_receive) debug_printf("SMTP<< %s\n", cmd_buffer);
513
514 /* NULLs are not allowed in SMTP commands */
515
516 if (hadnull) return BADCHAR_CMD;
517
518 /* Scan command list and return identity, having set the data pointer
519 to the start of the actual data characters. Check for SMTP synchronization
520 if required. */
521
522 for (p = cmd_list; p < cmd_list_end; p++)
523 {
524 if (strncmpic(cmd_buffer, US p->name, p->len) == 0)
525 {
526 if (smtp_inptr < smtp_inend && /* Outstanding input */
527 p->cmd < sync_cmd_limit && /* Command should sync */
528 check_sync && /* Local flag set */
529 smtp_enforce_sync && /* Global flag set */
530 sender_host_address != NULL && /* Not local input */
531 !sender_host_notsocket) /* Really is a socket */
532 return BADSYN_CMD;
533
534 /* Point after the command, but don't skip over leading spaces till after
535 the following test, so that if it fails, the command name can easily be
536 logged. */
537
538 smtp_data = cmd_buffer + p->len;
539
540 /* Count non-mail commands from those hosts that are controlled in this
541 way. The default is all hosts. We don't waste effort checking the list
542 until we get a non-mail command, but then cache the result to save checking
543 again. If there's a DEFER while checking the host, assume it's in the list.
544
545 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
546 start of each incoming message by fiddling with the value in the table. */
547
548 if (!p->is_mail_cmd)
549 {
550 if (count_nonmail == TRUE_UNSET) count_nonmail =
551 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
552 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
553 return TOO_MANY_NONMAIL_CMD;
554 }
555
556 /* Get the data pointer over leading spaces and return; if there is no data
557 for a command that expects it, we give the error centrally here. */
558
559 while (isspace(*smtp_data)) smtp_data++;
560 return (p->has_arg || *smtp_data == 0)? p->cmd : BADARG_CMD;
561 }
562 }
563
564 /* Enforce synchronization for unknown commands */
565
566 if (smtp_inptr < smtp_inend && /* Outstanding input */
567 check_sync && /* Local flag set */
568 smtp_enforce_sync && /* Global flag set */
569 sender_host_address != NULL && /* Not local input */
570 !sender_host_notsocket) /* Really is a socket */
571 return BADSYN_CMD;
572
573 return OTHER_CMD;
574 }
575
576
577
578 /*************************************************
579 * Forced closedown of call *
580 *************************************************/
581
582 /* This function is called from log.c when Exim is dying because of a serious
583 disaster, and also from some other places. If an incoming non-batched SMTP
584 channel is open, it swallows the rest of the incoming message if in the DATA
585 phase, sends the reply string, and gives an error to all subsequent commands
586 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
587 smtp_in.
588
589 Argument: SMTP reply string to send, excluding the code
590 Returns: nothing
591 */
592
593 void
594 smtp_closedown(uschar *message)
595 {
596 if (smtp_in == NULL || smtp_batched_input) return;
597 receive_swallow_smtp();
598 smtp_printf("421 %s\r\n", message);
599
600 for (;;)
601 {
602 switch(smtp_read_command(FALSE))
603 {
604 case EOF_CMD:
605 return;
606
607 case QUIT_CMD:
608 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
609 mac_smtp_fflush();
610 return;
611
612 case RSET_CMD:
613 smtp_printf("250 Reset OK\r\n");
614 break;
615
616 default:
617 smtp_printf("421 %s\r\n", message);
618 break;
619 }
620 }
621 }
622
623
624
625
626 /*************************************************
627 * Set up connection info for logging *
628 *************************************************/
629
630 /* This function is called when logging information about an SMTP connection.
631 It sets up appropriate source information, depending on the type of connection.
632
633 Argument: none
634 Returns: a string describing the connection
635 */
636
637 uschar *
638 smtp_get_connection_info(void)
639 {
640 if (host_checking)
641 return string_sprintf("SMTP connection from %s", sender_fullhost);
642
643 if (sender_host_unknown || sender_host_notsocket)
644 return string_sprintf("SMTP connection from %s", sender_ident);
645
646 if (is_inetd)
647 return string_sprintf("SMTP connection from %s (via inetd)", sender_fullhost);
648
649 if ((log_extra_selector & LX_incoming_interface) != 0 &&
650 interface_address != NULL)
651 return string_sprintf("SMTP connection from %s I=[%s]:%d", sender_fullhost,
652 interface_address, interface_port);
653
654 return string_sprintf("SMTP connection from %s", sender_fullhost);
655 }
656
657
658
659 /*************************************************
660 * Check HELO line and set sender_helo_name *
661 *************************************************/
662
663 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
664 the domain name of the sending host, or an ip literal in square brackets. The
665 arrgument is placed in sender_helo_name, which is in malloc store, because it
666 must persist over multiple incoming messages. If helo_accept_junk is set, this
667 host is permitted to send any old junk (needed for some broken hosts).
668 Otherwise, helo_allow_chars can be used for rogue characters in general
669 (typically people want to let in underscores).
670
671 Argument:
672 s the data portion of the line (already past any white space)
673
674 Returns: TRUE or FALSE
675 */
676
677 static BOOL
678 check_helo(uschar *s)
679 {
680 uschar *start = s;
681 uschar *end = s + Ustrlen(s);
682 BOOL yield = helo_accept_junk;
683
684 /* Discard any previous helo name */
685
686 if (sender_helo_name != NULL)
687 {
688 store_free(sender_helo_name);
689 sender_helo_name = NULL;
690 }
691
692 /* Skip tests if junk is permitted. */
693
694 if (!yield)
695 {
696 /* Allow the new standard form for IPv6 address literals, namely,
697 [IPv6:....], and because someone is bound to use it, allow an equivalent
698 IPv4 form. Allow plain addresses as well. */
699
700 if (*s == '[')
701 {
702 if (end[-1] == ']')
703 {
704 end[-1] = 0;
705 if (strncmpic(s, US"[IPv6:", 6) == 0)
706 yield = (string_is_ip_address(s+6, NULL) == 6);
707 else if (strncmpic(s, US"[IPv4:", 6) == 0)
708 yield = (string_is_ip_address(s+6, NULL) == 4);
709 else
710 yield = (string_is_ip_address(s+1, NULL) != 0);
711 end[-1] = ']';
712 }
713 }
714
715 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
716 that have been configured (usually underscore - sigh). */
717
718 else if (*s != 0)
719 {
720 yield = TRUE;
721 while (*s != 0)
722 {
723 if (!isalnum(*s) && *s != '.' && *s != '-' &&
724 Ustrchr(helo_allow_chars, *s) == NULL)
725 {
726 yield = FALSE;
727 break;
728 }
729 s++;
730 }
731 }
732 }
733
734 /* Save argument if OK */
735
736 if (yield) sender_helo_name = string_copy_malloc(start);
737 return yield;
738 }
739
740
741
742
743
744 /*************************************************
745 * Extract SMTP command option *
746 *************************************************/
747
748 /* This function picks the next option setting off the end of smtp_data. It
749 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
750 things that can appear there.
751
752 Arguments:
753 name point this at the name
754 value point this at the data string
755
756 Returns: TRUE if found an option
757 */
758
759 static BOOL
760 extract_option(uschar **name, uschar **value)
761 {
762 uschar *n;
763 uschar *v = smtp_data + Ustrlen(smtp_data) -1;
764 while (isspace(*v)) v--;
765 v[1] = 0;
766
767 while (v > smtp_data && *v != '=' && !isspace(*v)) v--;
768 if (*v != '=') return FALSE;
769
770 n = v;
771 while(isalpha(n[-1])) n--;
772
773 if (n[-1] != ' ') return FALSE;
774
775 n[-1] = 0;
776 *name = n;
777 *v++ = 0;
778 *value = v;
779 return TRUE;
780 }
781
782
783
784
785
786
787
788 /*************************************************
789 * Reset for new message *
790 *************************************************/
791
792 /* This function is called whenever the SMTP session is reset from
793 within either of the setup functions.
794
795 Argument: the stacking pool storage reset point
796 Returns: nothing
797 */
798
799 static void
800 smtp_reset(void *reset_point)
801 {
802 int i;
803 store_reset(reset_point);
804 recipients_list = NULL;
805 rcpt_count = rcpt_defer_count = rcpt_fail_count =
806 raw_recipients_count = recipients_count = recipients_list_max = 0;
807 message_linecount = 0;
808 message_size = -1;
809 acl_warn_headers = NULL;
810 queue_only_policy = FALSE;
811 deliver_freeze = FALSE; /* Can be set by ACL */
812 fake_response = OK; /* Can be set by ACL */
813 #ifdef WITH_CONTENT_SCAN
814 no_mbox_unspool = FALSE; /* Can be set by ACL */
815 #endif
816 submission_mode = FALSE; /* Can be set by ACL */
817 active_local_from_check = local_from_check; /* Can be set by ACL */
818 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
819 sender_address = NULL;
820 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
821 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
822 sender_verified_list = NULL; /* No senders verified */
823 memset(sender_address_cache, 0, sizeof(sender_address_cache));
824 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
825 authenticated_sender = NULL;
826 #ifdef EXPERIMENTAL_BRIGHTMAIL
827 bmi_run = 0;
828 bmi_verdicts = NULL;
829 #endif
830 #ifdef EXPERIMENTAL_DOMAINKEYS
831 dk_do_verify = 0;
832 #endif
833 #ifdef EXPERIMENTAL_SPF
834 spf_header_comment = NULL;
835 spf_received = NULL;
836 spf_result = NULL;
837 spf_smtp_comment = NULL;
838 #endif
839 body_linecount = body_zerocount = 0;
840
841 sender_rate = sender_rate_limit = sender_rate_period = NULL;
842 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
843 /* Note that ratelimiters_conn persists across resets. */
844
845 for (i = 0; i < ACL_M_MAX; i++) acl_var[ACL_C_MAX + i] = NULL;
846
847 /* The message body variables use malloc store. They may be set if this is
848 not the first message in an SMTP session and the previous message caused them
849 to be referenced in an ACL. */
850
851 if (message_body != NULL)
852 {
853 store_free(message_body);
854 message_body = NULL;
855 }
856
857 if (message_body_end != NULL)
858 {
859 store_free(message_body_end);
860 message_body_end = NULL;
861 }
862
863 /* Warning log messages are also saved in malloc store. They are saved to avoid
864 repetition in the same message, but it seems right to repeat them for different
865 messagess. */
866
867 while (acl_warn_logged != NULL)
868 {
869 string_item *this = acl_warn_logged;
870 acl_warn_logged = acl_warn_logged->next;
871 store_free(this);
872 }
873 }
874
875
876
877
878
879 /*************************************************
880 * Initialize for incoming batched SMTP message *
881 *************************************************/
882
883 /* This function is called from smtp_setup_msg() in the case when
884 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
885 of messages in one file with SMTP commands between them. All errors must be
886 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
887 relevant. After an error on a sender, or an invalid recipient, the remainder
888 of the message is skipped. The value of received_protocol is already set.
889
890 Argument: none
891 Returns: > 0 message successfully started (reached DATA)
892 = 0 QUIT read or end of file reached
893 < 0 should not occur
894 */
895
896 static int
897 smtp_setup_batch_msg(void)
898 {
899 int done = 0;
900 void *reset_point = store_get(0);
901
902 /* Save the line count at the start of each transaction - single commands
903 like HELO and RSET count as whole transactions. */
904
905 bsmtp_transaction_linecount = receive_linecount;
906
907 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
908
909 smtp_reset(reset_point); /* Reset for start of message */
910
911 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
912 value. The values are 2 larger than the required yield of the function. */
913
914 while (done <= 0)
915 {
916 uschar *errmess;
917 uschar *recipient = NULL;
918 int start, end, sender_domain, recipient_domain;
919
920 switch(smtp_read_command(FALSE))
921 {
922 /* The HELO/EHLO commands set sender_address_helo if they have
923 valid data; otherwise they are ignored, except that they do
924 a reset of the state. */
925
926 case HELO_CMD:
927 case EHLO_CMD:
928
929 check_helo(smtp_data);
930 /* Fall through */
931
932 case RSET_CMD:
933 smtp_reset(reset_point);
934 bsmtp_transaction_linecount = receive_linecount;
935 break;
936
937
938 /* The MAIL FROM command requires an address as an operand. All we
939 do here is to parse it for syntactic correctness. The form "<>" is
940 a special case which converts into an empty string. The start/end
941 pointers in the original are not used further for this address, as
942 it is the canonical extracted address which is all that is kept. */
943
944 case MAIL_CMD:
945 if (sender_address != NULL)
946 /* The function moan_smtp_batch() does not return. */
947 moan_smtp_batch(cmd_buffer, "503 Sender already given");
948
949 if (smtp_data[0] == 0)
950 /* The function moan_smtp_batch() does not return. */
951 moan_smtp_batch(cmd_buffer, "501 MAIL FROM must have an address operand");
952
953 /* Reset to start of message */
954
955 smtp_reset(reset_point);
956
957 /* Apply SMTP rewrite */
958
959 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
960 rewrite_one(smtp_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
961 US"", global_rewrite_rules) : smtp_data;
962
963 /* Extract the address; the TRUE flag allows <> as valid */
964
965 raw_sender =
966 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
967 TRUE);
968
969 if (raw_sender == NULL)
970 /* The function moan_smtp_batch() does not return. */
971 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
972
973 sender_address = string_copy(raw_sender);
974
975 /* Qualify unqualified sender addresses if permitted to do so. */
976
977 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
978 {
979 if (allow_unqualified_sender)
980 {
981 sender_address = rewrite_address_qualify(sender_address, FALSE);
982 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
983 "and rewritten\n", raw_sender);
984 }
985 /* The function moan_smtp_batch() does not return. */
986 else moan_smtp_batch(cmd_buffer, "501 sender address must contain "
987 "a domain");
988 }
989 break;
990
991
992 /* The RCPT TO command requires an address as an operand. All we do
993 here is to parse it for syntactic correctness. There may be any number
994 of RCPT TO commands, specifying multiple senders. We build them all into
995 a data structure that is in argc/argv format. The start/end values
996 given by parse_extract_address are not used, as we keep only the
997 extracted address. */
998
999 case RCPT_CMD:
1000 if (sender_address == NULL)
1001 /* The function moan_smtp_batch() does not return. */
1002 moan_smtp_batch(cmd_buffer, "503 No sender yet given");
1003
1004 if (smtp_data[0] == 0)
1005 /* The function moan_smtp_batch() does not return. */
1006 moan_smtp_batch(cmd_buffer, "501 RCPT TO must have an address operand");
1007
1008 /* Check maximum number allowed */
1009
1010 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1011 /* The function moan_smtp_batch() does not return. */
1012 moan_smtp_batch(cmd_buffer, "%s too many recipients",
1013 recipients_max_reject? "552": "452");
1014
1015 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1016 recipient address */
1017
1018 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1019 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
1020 global_rewrite_rules) : smtp_data;
1021
1022 /* rfc821_domains = TRUE; << no longer needed */
1023 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1024 &recipient_domain, FALSE);
1025 /* rfc821_domains = FALSE; << no longer needed */
1026
1027 if (recipient == NULL)
1028 /* The function moan_smtp_batch() does not return. */
1029 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
1030
1031 /* If the recipient address is unqualified, qualify it if permitted. Then
1032 add it to the list of recipients. */
1033
1034 if (recipient_domain == 0)
1035 {
1036 if (allow_unqualified_recipient)
1037 {
1038 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1039 recipient);
1040 recipient = rewrite_address_qualify(recipient, TRUE);
1041 }
1042 /* The function moan_smtp_batch() does not return. */
1043 else moan_smtp_batch(cmd_buffer, "501 recipient address must contain "
1044 "a domain");
1045 }
1046 receive_add_recipient(recipient, -1);
1047 break;
1048
1049
1050 /* The DATA command is legal only if it follows successful MAIL FROM
1051 and RCPT TO commands. This function is complete when a valid DATA
1052 command is encountered. */
1053
1054 case DATA_CMD:
1055 if (sender_address == NULL || recipients_count <= 0)
1056 {
1057 /* The function moan_smtp_batch() does not return. */
1058 if (sender_address == NULL)
1059 moan_smtp_batch(cmd_buffer,
1060 "503 MAIL FROM:<sender> command must precede DATA");
1061 else
1062 moan_smtp_batch(cmd_buffer,
1063 "503 RCPT TO:<recipient> must precede DATA");
1064 }
1065 else
1066 {
1067 done = 3; /* DATA successfully achieved */
1068 message_ended = END_NOTENDED; /* Indicate in middle of message */
1069 }
1070 break;
1071
1072
1073 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1074
1075 case VRFY_CMD:
1076 case EXPN_CMD:
1077 case HELP_CMD:
1078 case NOOP_CMD:
1079 case ETRN_CMD:
1080 bsmtp_transaction_linecount = receive_linecount;
1081 break;
1082
1083
1084 case EOF_CMD:
1085 case QUIT_CMD:
1086 done = 2;
1087 break;
1088
1089
1090 case BADARG_CMD:
1091 /* The function moan_smtp_batch() does not return. */
1092 moan_smtp_batch(cmd_buffer, "501 Unexpected argument data");
1093 break;
1094
1095
1096 case BADCHAR_CMD:
1097 /* The function moan_smtp_batch() does not return. */
1098 moan_smtp_batch(cmd_buffer, "501 Unexpected NULL in SMTP command");
1099 break;
1100
1101
1102 default:
1103 /* The function moan_smtp_batch() does not return. */
1104 moan_smtp_batch(cmd_buffer, "500 Command unrecognized");
1105 break;
1106 }
1107 }
1108
1109 return done - 2; /* Convert yield values */
1110 }
1111
1112
1113
1114
1115 /*************************************************
1116 * Start an SMTP session *
1117 *************************************************/
1118
1119 /* This function is called at the start of an SMTP session. Thereafter,
1120 smtp_setup_msg() is called to initiate each separate message. This
1121 function does host-specific testing, and outputs the banner line.
1122
1123 Arguments: none
1124 Returns: FALSE if the session can not continue; something has
1125 gone wrong, or the connection to the host is blocked
1126 */
1127
1128 BOOL
1129 smtp_start_session(void)
1130 {
1131 int size = 256;
1132 int i, ptr;
1133 uschar *p, *s, *ss;
1134
1135 /* If we are running in the test harness, and the incoming call is from
1136 127.0.0.2 (sic), have a short delay. This makes it possible to test handling of
1137 input sent too soon (before the banner is output). */
1138
1139 if (running_in_test_harness &&
1140 sender_host_address != NULL &&
1141 Ustrcmp(sender_host_address, "127.0.0.2") == 0)
1142 sleep(1);
1143
1144 /* Default values for certain variables */
1145
1146 helo_seen = esmtp = helo_accept_junk = FALSE;
1147 count_nonmail = TRUE_UNSET;
1148 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1149 smtp_delay_mail = smtp_rlm_base;
1150 auth_advertised = FALSE;
1151 pipelining_advertised = FALSE;
1152 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1153
1154 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1155
1156 sender_host_authenticated = NULL;
1157 authenticated_by = NULL;
1158
1159 #ifdef SUPPORT_TLS
1160 tls_cipher = tls_peerdn = NULL;
1161 tls_advertised = FALSE;
1162 #endif
1163
1164 /* Reset ACL connection variables */
1165
1166 for (i = 0; i < ACL_C_MAX; i++) acl_var[i] = NULL;
1167
1168 cmd_buffer = (uschar *)malloc(cmd_buffer_size + 1); /* allow for trailing 0 */
1169 if (cmd_buffer == NULL)
1170 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1171 "malloc() failed for SMTP command buffer");
1172
1173 /* For batched input, the protocol setting can be overridden from the
1174 command line by a trusted caller. */
1175
1176 if (smtp_batched_input)
1177 {
1178 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1179 }
1180
1181 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1182 reset later if any of EHLO/AUTH/STARTTLS are received. */
1183
1184 else
1185 received_protocol =
1186 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1187
1188 /* Set up the buffer for inputting using direct read() calls, and arrange to
1189 call the local functions instead of the standard C ones. */
1190
1191 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1192 if (smtp_inbuffer == NULL)
1193 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1194 receive_getc = smtp_getc;
1195 receive_ungetc = smtp_ungetc;
1196 receive_feof = smtp_feof;
1197 receive_ferror = smtp_ferror;
1198 smtp_inptr = smtp_inend = smtp_inbuffer;
1199 smtp_had_eof = smtp_had_error = 0;
1200
1201 /* Set up the message size limit; this may be host-specific */
1202
1203 thismessage_size_limit = expand_string_integer(message_size_limit);
1204 if (thismessage_size_limit < 0)
1205 {
1206 if (thismessage_size_limit == -1)
1207 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1208 "%s", expand_string_message);
1209 else
1210 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1211 "%s", expand_string_message);
1212 smtp_closedown(US"Temporary local problem - please try later");
1213 return FALSE;
1214 }
1215
1216 /* When a message is input locally via the -bs or -bS options, sender_host_
1217 unknown is set unless -oMa was used to force an IP address, in which case it
1218 is checked like a real remote connection. When -bs is used from inetd, this
1219 flag is not set, causing the sending host to be checked. The code that deals
1220 with IP source routing (if configured) is never required for -bs or -bS and
1221 the flag sender_host_notsocket is used to suppress it.
1222
1223 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1224 reserve for certain hosts and/or networks. */
1225
1226 if (!sender_host_unknown)
1227 {
1228 int rc;
1229 BOOL reserved_host = FALSE;
1230
1231 /* Look up IP options (source routing info) on the socket if this is not an
1232 -oMa "host", and if any are found, log them and drop the connection.
1233
1234 Linux (and others now, see below) is different to everyone else, so there
1235 has to be some conditional compilation here. Versions of Linux before 2.1.15
1236 used a structure whose name was "options". Somebody finally realized that
1237 this name was silly, and it got changed to "ip_options". I use the
1238 newer name here, but there is a fudge in the script that sets up os.h
1239 to define a macro in older Linux systems.
1240
1241 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1242 glibc 2, which has chosen ip_opts for the structure name. This is now
1243 really a glibc thing rather than a Linux thing, so the condition name
1244 has been changed to reflect this. It is relevant also to GNU/Hurd.
1245
1246 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1247 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1248 a special macro defined in the os.h file.
1249
1250 Some DGUX versions on older hardware appear not to support IP options at
1251 all, so there is now a general macro which can be set to cut out this
1252 support altogether.
1253
1254 How to do this properly in IPv6 is not yet known. */
1255
1256 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1257
1258 #ifdef GLIBC_IP_OPTIONS
1259 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1260 #define OPTSTYLE 1
1261 #else
1262 #define OPTSTYLE 2
1263 #endif
1264 #elif defined DARWIN_IP_OPTIONS
1265 #define OPTSTYLE 2
1266 #else
1267 #define OPTSTYLE 3
1268 #endif
1269
1270 if (!host_checking && !sender_host_notsocket)
1271 {
1272 #if OPTSTYLE == 1
1273 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1274 struct ip_options *ipopt = store_get(optlen);
1275 #elif OPTSTYLE == 2
1276 struct ip_opts ipoptblock;
1277 struct ip_opts *ipopt = &ipoptblock;
1278 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1279 #else
1280 struct ipoption ipoptblock;
1281 struct ipoption *ipopt = &ipoptblock;
1282 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1283 #endif
1284
1285 /* Occasional genuine failures of getsockopt() have been seen - for
1286 example, "reset by peer". Therefore, just log and give up on this
1287 call, unless the error is ENOPROTOOPT. This error is given by systems
1288 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1289 of writing. So for that error, carry on - we just can't do an IP options
1290 check. */
1291
1292 DEBUG(D_receive) debug_printf("checking for IP options\n");
1293
1294 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1295 &optlen) < 0)
1296 {
1297 if (errno != ENOPROTOOPT)
1298 {
1299 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1300 host_and_ident(FALSE), strerror(errno));
1301 smtp_printf("451 SMTP service not available\r\n");
1302 return FALSE;
1303 }
1304 }
1305
1306 /* Deal with any IP options that are set. On the systems I have looked at,
1307 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1308 more logging data than will fit in big_buffer. Nevertheless, after somebody
1309 questioned this code, I've added in some paranoid checking. */
1310
1311 else if (optlen > 0)
1312 {
1313 uschar *p = big_buffer;
1314 uschar *pend = big_buffer + big_buffer_size;
1315 uschar *opt, *adptr;
1316 int optcount;
1317 struct in_addr addr;
1318
1319 #if OPTSTYLE == 1
1320 uschar *optstart = (uschar *)(ipopt->__data);
1321 #elif OPTSTYLE == 2
1322 uschar *optstart = (uschar *)(ipopt->ip_opts);
1323 #else
1324 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1325 #endif
1326
1327 DEBUG(D_receive) debug_printf("IP options exist\n");
1328
1329 Ustrcpy(p, "IP options on incoming call:");
1330 p += Ustrlen(p);
1331
1332 for (opt = optstart; opt != NULL &&
1333 opt < (uschar *)(ipopt) + optlen;)
1334 {
1335 switch (*opt)
1336 {
1337 case IPOPT_EOL:
1338 opt = NULL;
1339 break;
1340
1341 case IPOPT_NOP:
1342 opt++;
1343 break;
1344
1345 case IPOPT_SSRR:
1346 case IPOPT_LSRR:
1347 if (!string_format(p, pend-p, " %s [@%s",
1348 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1349 #if OPTSTYLE == 1
1350 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1351 #elif OPTSTYLE == 2
1352 inet_ntoa(ipopt->ip_dst)))
1353 #else
1354 inet_ntoa(ipopt->ipopt_dst)))
1355 #endif
1356 {
1357 opt = NULL;
1358 break;
1359 }
1360
1361 p += Ustrlen(p);
1362 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1363 adptr = opt + 3;
1364 while (optcount-- > 0)
1365 {
1366 memcpy(&addr, adptr, sizeof(addr));
1367 if (!string_format(p, pend - p - 1, "%s%s",
1368 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1369 {
1370 opt = NULL;
1371 break;
1372 }
1373 p += Ustrlen(p);
1374 adptr += sizeof(struct in_addr);
1375 }
1376 *p++ = ']';
1377 opt += opt[1];
1378 break;
1379
1380 default:
1381 {
1382 int i;
1383 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1384 Ustrcat(p, "[ ");
1385 p += 2;
1386 for (i = 0; i < opt[1]; i++)
1387 {
1388 sprintf(CS p, "%2.2x ", opt[i]);
1389 p += 3;
1390 }
1391 *p++ = ']';
1392 }
1393 opt += opt[1];
1394 break;
1395 }
1396 }
1397
1398 *p = 0;
1399 log_write(0, LOG_MAIN, "%s", big_buffer);
1400
1401 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1402
1403 log_write(0, LOG_MAIN|LOG_REJECT,
1404 "connection from %s refused (IP options)", host_and_ident(FALSE));
1405
1406 smtp_printf("554 SMTP service not available\r\n");
1407 return FALSE;
1408 }
1409
1410 /* Length of options = 0 => there are no options */
1411
1412 else DEBUG(D_receive) debug_printf("no IP options found\n");
1413 }
1414 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1415
1416 /* Set keep-alive in socket options. The option is on by default. This
1417 setting is an attempt to get rid of some hanging connections that stick in
1418 read() when the remote end (usually a dialup) goes away. */
1419
1420 if (smtp_accept_keepalive && !sender_host_notsocket)
1421 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1422
1423 /* If the current host matches host_lookup, set the name by doing a
1424 reverse lookup. On failure, sender_host_name will be NULL and
1425 host_lookup_failed will be TRUE. This may or may not be serious - optional
1426 checks later. */
1427
1428 if (verify_check_host(&host_lookup) == OK)
1429 {
1430 (void)host_name_lookup();
1431 host_build_sender_fullhost();
1432 }
1433
1434 /* Delay this until we have the full name, if it is looked up. */
1435
1436 set_process_info("handling incoming connection from %s",
1437 host_and_ident(FALSE));
1438
1439 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1440 smtps port for use with older style SSL MTAs. */
1441
1442 #ifdef SUPPORT_TLS
1443 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1444 return FALSE;
1445 #endif
1446
1447 /* Test for explicit connection rejection */
1448
1449 if (verify_check_host(&host_reject_connection) == OK)
1450 {
1451 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1452 "from %s (host_reject_connection)", host_and_ident(FALSE));
1453 smtp_printf("554 SMTP service not available\r\n");
1454 return FALSE;
1455 }
1456
1457 /* Test with TCP Wrappers if so configured */
1458
1459 #ifdef USE_TCP_WRAPPERS
1460 if (!hosts_ctl("exim",
1461 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1462 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1463 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1464 {
1465 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1466 log_write(L_connection_reject,
1467 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1468 "(tcp wrappers)", host_and_ident(FALSE));
1469 smtp_printf("554 SMTP service not available\r\n");
1470 return FALSE;
1471 }
1472 #endif
1473
1474 /* Check for reserved slots. Note that the count value doesn't include
1475 this process, as it gets upped in the parent process. */
1476
1477 if (smtp_accept_max > 0 &&
1478 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1479 {
1480 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1481 {
1482 log_write(L_connection_reject,
1483 LOG_MAIN, "temporarily refused connection from %s: not in "
1484 "reserve list: connected=%d max=%d reserve=%d%s",
1485 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1486 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1487 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1488 "please try again later\r\n", smtp_active_hostname);
1489 return FALSE;
1490 }
1491 reserved_host = TRUE;
1492 }
1493
1494 /* If a load level above which only messages from reserved hosts are
1495 accepted is set, check the load. For incoming calls via the daemon, the
1496 check is done in the superior process if there are no reserved hosts, to
1497 save a fork. In all cases, the load average will already be available
1498 in a global variable at this point. */
1499
1500 if (smtp_load_reserve >= 0 &&
1501 load_average > smtp_load_reserve &&
1502 !reserved_host &&
1503 verify_check_host(&smtp_reserve_hosts) != OK)
1504 {
1505 log_write(L_connection_reject,
1506 LOG_MAIN, "temporarily refused connection from %s: not in "
1507 "reserve list and load average = %.2f", host_and_ident(FALSE),
1508 (double)load_average/1000.0);
1509 smtp_printf("421 %s: Too much load; please try again later\r\n",
1510 smtp_active_hostname);
1511 return FALSE;
1512 }
1513
1514 /* Determine whether unqualified senders or recipients are permitted
1515 for this host. Unfortunately, we have to do this every time, in order to
1516 set the flags so that they can be inspected when considering qualifying
1517 addresses in the headers. For a site that permits no qualification, this
1518 won't take long, however. */
1519
1520 allow_unqualified_sender =
1521 verify_check_host(&sender_unqualified_hosts) == OK;
1522
1523 allow_unqualified_recipient =
1524 verify_check_host(&recipient_unqualified_hosts) == OK;
1525
1526 /* Determine whether HELO/EHLO is required for this host. The requirement
1527 can be hard or soft. */
1528
1529 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1530 if (!helo_required)
1531 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1532
1533 /* Determine whether this hosts is permitted to send syntactic junk
1534 after a HELO or EHLO command. */
1535
1536 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1537 }
1538
1539 /* For batch SMTP input we are now done. */
1540
1541 if (smtp_batched_input) return TRUE;
1542
1543 /* Run the ACL if it exists */
1544
1545 if (acl_smtp_connect != NULL)
1546 {
1547 int rc;
1548 uschar *user_msg, *log_msg;
1549 smtp_data = US"in \"connect\" ACL"; /* For logged failure message */
1550 rc = acl_check(ACL_WHERE_CONNECT, US"", acl_smtp_connect, &user_msg,
1551 &log_msg);
1552 if (rc != OK)
1553 {
1554 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1555 return FALSE;
1556 }
1557 }
1558
1559 /* Output the initial message for a two-way SMTP connection. It may contain
1560 newlines, which then cause a multi-line response to be given. */
1561
1562 s = expand_string(smtp_banner);
1563 if (s == NULL)
1564 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1565 "failed: %s", smtp_banner, expand_string_message);
1566
1567 /* Remove any terminating newlines; might as well remove trailing space too */
1568
1569 p = s + Ustrlen(s);
1570 while (p > s && isspace(p[-1])) p--;
1571 *p = 0;
1572
1573 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1574 is all contained in a single IP packet. The original code wrote out the
1575 greeting using several calls to fprint/fputc, and on busy servers this could
1576 cause it to be split over more than one packet - which caused CC:Mail to fall
1577 over when it got the second part of the greeting after sending its first
1578 command. Sigh. To try to avoid this, build the complete greeting message
1579 first, and output it in one fell swoop. This gives a better chance of it
1580 ending up as a single packet. */
1581
1582 ss = store_get(size);
1583 ptr = 0;
1584
1585 p = s;
1586 do /* At least once, in case we have an empty string */
1587 {
1588 int len;
1589 uschar *linebreak = Ustrchr(p, '\n');
1590 if (linebreak == NULL)
1591 {
1592 len = Ustrlen(p);
1593 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1594 }
1595 else
1596 {
1597 len = linebreak - p;
1598 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1599 }
1600 ss = string_cat(ss, &size, &ptr, p, len);
1601 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1602 p += len;
1603 if (linebreak != NULL) p++;
1604 }
1605 while (*p != 0);
1606
1607 ss[ptr] = 0; /* string_cat leaves room for this */
1608
1609 /* Before we write the banner, check that there is no input pending, unless
1610 this synchronisation check is disabled. */
1611
1612 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1613 {
1614 fd_set fds;
1615 struct timeval tzero;
1616 tzero.tv_sec = 0;
1617 tzero.tv_usec = 0;
1618 FD_ZERO(&fds);
1619 FD_SET(fileno(smtp_in), &fds);
1620 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1621 &tzero) > 0)
1622 {
1623 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1624 if (rc > 0)
1625 {
1626 if (rc > 150) rc = 150;
1627 smtp_inbuffer[rc] = 0;
1628 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1629 "synchronization error (input sent without waiting for greeting): "
1630 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1631 string_printing(smtp_inbuffer));
1632 smtp_printf("554 SMTP synchronization error\r\n");
1633 return FALSE;
1634 }
1635 }
1636 }
1637
1638 /* Now output the banner */
1639
1640 smtp_printf("%s", ss);
1641 return TRUE;
1642 }
1643
1644
1645
1646
1647
1648 /*************************************************
1649 * Handle SMTP syntax and protocol errors *
1650 *************************************************/
1651
1652 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1653 to do so. Then transmit the error response. The return value depends on the
1654 number of syntax and protocol errors in this SMTP session.
1655
1656 Arguments:
1657 type error type, given as a log flag bit
1658 code response code; <= 0 means don't send a response
1659 data data to reflect in the response (can be NULL)
1660 errmess the error message
1661
1662 Returns: -1 limit of syntax/protocol errors NOT exceeded
1663 +1 limit of syntax/protocol errors IS exceeded
1664
1665 These values fit in with the values of the "done" variable in the main
1666 processing loop in smtp_setup_msg(). */
1667
1668 static int
1669 synprot_error(int type, int code, uschar *data, uschar *errmess)
1670 {
1671 int yield = -1;
1672
1673 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1674 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1675 string_printing(cmd_buffer), host_and_ident(TRUE), errmess);
1676
1677 if (++synprot_error_count > smtp_max_synprot_errors)
1678 {
1679 yield = 1;
1680 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1681 "syntax or protocol errors (last command was \"%s\")",
1682 host_and_ident(FALSE), cmd_buffer);
1683 }
1684
1685 if (code > 0)
1686 {
1687 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1688 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1689 if (yield == 1)
1690 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1691 }
1692
1693 return yield;
1694 }
1695
1696
1697
1698
1699 /*************************************************
1700 * Log incomplete transactions *
1701 *************************************************/
1702
1703 /* This function is called after a transaction has been aborted by RSET, QUIT,
1704 connection drops or other errors. It logs the envelope information received
1705 so far in order to preserve address verification attempts.
1706
1707 Argument: string to indicate what aborted the transaction
1708 Returns: nothing
1709 */
1710
1711 static void
1712 incomplete_transaction_log(uschar *what)
1713 {
1714 if (sender_address == NULL || /* No transaction in progress */
1715 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1716 ) return;
1717
1718 /* Build list of recipients for logging */
1719
1720 if (recipients_count > 0)
1721 {
1722 int i;
1723 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1724 for (i = 0; i < recipients_count; i++)
1725 raw_recipients[i] = recipients_list[i].address;
1726 raw_recipients_count = recipients_count;
1727 }
1728
1729 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1730 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1731 }
1732
1733
1734
1735
1736 /*************************************************
1737 * Send SMTP response, possibly multiline *
1738 *************************************************/
1739
1740 /* There are, it seems, broken clients out there that cannot handle multiline
1741 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1742 output nothing for non-final calls, and only the first line for anything else.
1743
1744 Arguments:
1745 code SMTP code
1746 final FALSE if the last line isn't the final line
1747 msg message text, possibly containing newlines
1748
1749 Returns: nothing
1750 */
1751
1752 void
1753 smtp_respond(int code, BOOL final, uschar *msg)
1754 {
1755 if (!final && no_multiline_responses) return;
1756
1757 for (;;)
1758 {
1759 uschar *nl = Ustrchr(msg, '\n');
1760 if (nl == NULL)
1761 {
1762 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1763 return;
1764 }
1765 else if (nl[1] == 0 || no_multiline_responses)
1766 {
1767 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1768 return;
1769 }
1770 else
1771 {
1772 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1773 msg = nl + 1;
1774 while (isspace(*msg)) msg++;
1775 }
1776 }
1777 }
1778
1779
1780
1781
1782 /*************************************************
1783 * Handle an ACL failure *
1784 *************************************************/
1785
1786 /* This function is called when acl_check() fails. As well as calls from within
1787 this module, it is called from receive.c for an ACL after DATA. It sorts out
1788 logging the incident, and sets up the error response. A message containing
1789 newlines is turned into a multiline SMTP response, but for logging, only the
1790 first line is used.
1791
1792 There's a table of the response codes to use in globals.c, along with the table
1793 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1794 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1795 that the response should be 252 in the disabled state, because there are broken
1796 clients that try VRFY before RCPT. A 5xx response should be given only when the
1797 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1798 given on refusal, and for AUTH, 503.
1799
1800 Arguments:
1801 where where the ACL was called from
1802 rc the failure code
1803 user_msg a message that can be included in an SMTP response
1804 log_msg a message for logging
1805
1806 Returns: 0 in most cases
1807 2 if the failure code was FAIL_DROP, in which case the
1808 SMTP connection should be dropped (this value fits with the
1809 "done" variable in smtp_setup_msg() below)
1810 */
1811
1812 int
1813 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1814 {
1815 int code = acl_wherecodes[where];
1816 BOOL drop = rc == FAIL_DROP;
1817 uschar *lognl;
1818 uschar *sender_info = US"";
1819 uschar *what = (where == ACL_WHERE_PREDATA)? US"DATA" :
1820 #ifdef WITH_CONTENT_SCAN
1821 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1822 #endif
1823 (where == ACL_WHERE_DATA)? US"after DATA" :
1824 string_sprintf("%s %s", acl_wherenames[where], smtp_data);
1825
1826 if (drop) rc = FAIL;
1827
1828 /* We used to have sender_address here; however, there was a bug that was not
1829 updating sender_address after a rewrite during a verify. When this bug was
1830 fixed, sender_address at this point became the rewritten address. I'm not sure
1831 this is what should be logged, so I've changed to logging the unrewritten
1832 address to retain backward compatibility. */
1833
1834 #ifndef WITH_CONTENT_SCAN
1835 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1836 #else
1837 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1838 #endif
1839 {
1840 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1841 sender_address_unrewritten : sender_address);
1842 }
1843
1844 /* If there's been a sender verification failure with a specific message, and
1845 we have not sent a response about it yet, do so now, as a preliminary line for
1846 failures, but not defers. However, log it in both cases. */
1847
1848 if (sender_verified_failed != NULL &&
1849 !testflag(sender_verified_failed, af_sverify_told))
1850 {
1851 setflag(sender_verified_failed, af_sverify_told);
1852
1853 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1854 host_and_ident(TRUE),
1855 ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail",
1856 sender_verified_failed->address,
1857 (sender_verified_failed->message == NULL)? US"" :
1858 string_sprintf(": %s", sender_verified_failed->message));
1859
1860 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1861 smtp_respond(code, FALSE, string_sprintf(
1862 testflag(sender_verified_failed, af_verify_pmfail)?
1863 "Postmaster verification failed while checking <%s>\n%s\n"
1864 "Several RFCs state that you are required to have a postmaster\n"
1865 "mailbox for each mail domain. This host does not accept mail\n"
1866 "from domains whose servers reject the postmaster address."
1867 :
1868 testflag(sender_verified_failed, af_verify_nsfail)?
1869 "Callback setup failed while verifying <%s>\n%s\n"
1870 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1871 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1872 "RFC requirements, and stops you from receiving standard bounce\n"
1873 "messages. This host does not accept mail from domains whose servers\n"
1874 "refuse bounces."
1875 :
1876 "Verification failed for <%s>\n%s",
1877 sender_verified_failed->address,
1878 sender_verified_failed->user_message));
1879 }
1880
1881 /* Sort out text for logging */
1882
1883 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1884 lognl = Ustrchr(log_msg, '\n');
1885 if (lognl != NULL) *lognl = 0;
1886
1887 /* Send permanent failure response to the command, but the code used isn't
1888 always a 5xx one - see comments at the start of this function. If the original
1889 rc was FAIL_DROP we drop the connection and yield 2. */
1890
1891 if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1892 US"Administrative prohibition" : user_msg);
1893
1894 /* Send temporary failure response to the command. Don't give any details,
1895 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1896 verb, and for a header verify when smtp_return_error_details is set.
1897
1898 This conditional logic is all somewhat of a mess because of the odd
1899 interactions between temp_details and return_error_details. One day it should
1900 be re-implemented in a tidier fashion. */
1901
1902 else
1903 {
1904 if (acl_temp_details && user_msg != NULL)
1905 {
1906 if (smtp_return_error_details &&
1907 sender_verified_failed != NULL &&
1908 sender_verified_failed->message != NULL)
1909 {
1910 smtp_respond(451, FALSE, sender_verified_failed->message);
1911 }
1912 smtp_respond(451, TRUE, user_msg);
1913 }
1914 else
1915 smtp_printf("451 Temporary local problem - please try later\r\n");
1916 }
1917
1918 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
1919 Otherwise, log why it is closing if required and return 2. */
1920
1921 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1922 host_and_ident(TRUE),
1923 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1924
1925 if (!drop) return 0;
1926
1927 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1928 smtp_get_connection_info());
1929 return 2;
1930 }
1931
1932
1933
1934
1935 /*************************************************
1936 * Initialize for SMTP incoming message *
1937 *************************************************/
1938
1939 /* This function conducts the initial dialogue at the start of an incoming SMTP
1940 message, and builds a list of recipients. However, if the incoming message
1941 is part of a batch (-bS option) a separate function is called since it would
1942 be messy having tests splattered about all over this function. This function
1943 therefore handles the case where interaction is occurring. The input and output
1944 files are set up in smtp_in and smtp_out.
1945
1946 The global recipients_list is set to point to a vector of recipient_item
1947 blocks, whose number is given by recipients_count. This is extended by the
1948 receive_add_recipient() function. The global variable sender_address is set to
1949 the sender's address. The yield is +1 if a message has been successfully
1950 started, 0 if a QUIT command was encountered or the connection was refused from
1951 the particular host, or -1 if the connection was lost.
1952
1953 Argument: none
1954
1955 Returns: > 0 message successfully started (reached DATA)
1956 = 0 QUIT read or end of file reached or call refused
1957 < 0 lost connection
1958 */
1959
1960 int
1961 smtp_setup_msg(void)
1962 {
1963 int done = 0;
1964 BOOL toomany = FALSE;
1965 BOOL discarded = FALSE;
1966 BOOL last_was_rej_mail = FALSE;
1967 BOOL last_was_rcpt = FALSE;
1968 void *reset_point = store_get(0);
1969
1970 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
1971
1972 /* Reset for start of new message. We allow one RSET not to be counted as a
1973 nonmail command, for those MTAs that insist on sending it between every
1974 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
1975 TLS between messages (an Exim client may do this if it has messages queued up
1976 for the host). Note: we do NOT reset AUTH at this point. */
1977
1978 smtp_reset(reset_point);
1979 message_ended = END_NOTSTARTED;
1980
1981 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
1982 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
1983 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
1984 #ifdef SUPPORT_TLS
1985 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
1986 #endif
1987
1988 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
1989
1990 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
1991
1992 /* Batched SMTP is handled in a different function. */
1993
1994 if (smtp_batched_input) return smtp_setup_batch_msg();
1995
1996 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1997 value. The values are 2 larger than the required yield of the function. */
1998
1999 while (done <= 0)
2000 {
2001 uschar **argv;
2002 uschar *etrn_command;
2003 uschar *etrn_serialize_key;
2004 uschar *errmess;
2005 uschar *user_msg, *log_msg;
2006 uschar *recipient = NULL;
2007 uschar *hello = NULL;
2008 uschar *set_id = NULL;
2009 uschar *s, *ss;
2010 BOOL was_rej_mail = FALSE;
2011 BOOL was_rcpt = FALSE;
2012 void (*oldsignal)(int);
2013 pid_t pid;
2014 int start, end, sender_domain, recipient_domain;
2015 int ptr, size, rc;
2016 int c;
2017 auth_instance *au;
2018
2019 switch(smtp_read_command(TRUE))
2020 {
2021 /* The AUTH command is not permitted to occur inside a transaction, and may
2022 occur successfully only once per connection, and then only when we've
2023 advertised it. Actually, that isn't quite true. When TLS is started, all
2024 previous information about a connection must be discarded, so a new AUTH is
2025 permitted at that time.
2026
2027 AUTH is initially labelled as a "nonmail command" so that one occurrence
2028 doesn't get counted. We change the label here so that multiple failing
2029 AUTHS will eventually hit the nonmail threshold. */
2030
2031 case AUTH_CMD:
2032 authentication_failed = TRUE;
2033 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2034
2035 if (!auth_advertised)
2036 {
2037 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2038 US"AUTH command used when not advertised");
2039 break;
2040 }
2041 if (sender_host_authenticated != NULL)
2042 {
2043 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2044 US"already authenticated");
2045 break;
2046 }
2047 if (sender_address != NULL)
2048 {
2049 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2050 US"not permitted in mail transaction");
2051 break;
2052 }
2053
2054 /* Check the ACL */
2055
2056 if (acl_smtp_auth != NULL)
2057 {
2058 rc = acl_check(ACL_WHERE_AUTH, smtp_data, acl_smtp_auth, &user_msg,
2059 &log_msg);
2060 if (rc != OK)
2061 {
2062 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2063 break;
2064 }
2065 }
2066
2067 /* Find the name of the requested authentication mechanism. */
2068
2069 s = smtp_data;
2070 while ((c = *smtp_data) != 0 && !isspace(c))
2071 {
2072 if (!isalnum(c) && c != '-' && c != '_')
2073 {
2074 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2075 US"invalid character in authentication mechanism name");
2076 goto COMMAND_LOOP;
2077 }
2078 smtp_data++;
2079 }
2080
2081 /* If not at the end of the line, we must be at white space. Terminate the
2082 name and move the pointer on to any data that may be present. */
2083
2084 if (*smtp_data != 0)
2085 {
2086 *smtp_data++ = 0;
2087 while (isspace(*smtp_data)) smtp_data++;
2088 }
2089
2090 /* Search for an authentication mechanism which is configured for use
2091 as a server and which has been advertised. */
2092
2093 for (au = auths; au != NULL; au = au->next)
2094 {
2095 if (strcmpic(s, au->public_name) == 0 && au->server &&
2096 au->advertised) break;
2097 }
2098
2099 if (au == NULL)
2100 {
2101 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2102 string_sprintf("%s authentication mechanism not supported", s));
2103 break;
2104 }
2105
2106 /* Run the checking code, passing the remainder of the command
2107 line as data. Initialize $0 empty. The authenticator may set up
2108 other numeric variables. Afterwards, have a go at expanding the set_id
2109 string, even if authentication failed - for bad passwords it can be useful
2110 to log the userid. On success, require set_id to expand and exist, and
2111 put it in authenticated_id. Save this in permanent store, as the working
2112 store gets reset at HELO, RSET, etc. */
2113
2114 expand_nmax = 0;
2115 expand_nlength[0] = 0; /* $0 contains nothing */
2116
2117 c = (au->info->servercode)(au, smtp_data);
2118 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2119 expand_nmax = -1; /* Reset numeric variables */
2120
2121 /* The value of authenticated_id is stored in the spool file and printed in
2122 log lines. It must not contain binary zeros or newline characters. In
2123 normal use, it never will, but when playing around or testing, this error
2124 can (did) happen. To guard against this, ensure that the id contains only
2125 printing characters. */
2126
2127 if (set_id != NULL) set_id = string_printing(set_id);
2128
2129 /* For the non-OK cases, set up additional logging data if set_id
2130 is not empty. */
2131
2132 if (c != OK)
2133 {
2134 if (set_id != NULL && *set_id != 0)
2135 set_id = string_sprintf(" (set_id=%s)", set_id);
2136 else set_id = US"";
2137 }
2138
2139 /* Switch on the result */
2140
2141 switch(c)
2142 {
2143 case OK:
2144 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2145 {
2146 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2147 sender_host_authenticated = au->name;
2148 authentication_failed = FALSE;
2149 received_protocol =
2150 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2151 ((sender_host_address != NULL)? pnlocal : 0);
2152 s = ss = US"235 Authentication succeeded";
2153 authenticated_by = au;
2154 break;
2155 }
2156
2157 /* Authentication succeeded, but we failed to expand the set_id string.
2158 Treat this as a temporary error. */
2159
2160 auth_defer_msg = expand_string_message;
2161 /* Fall through */
2162
2163 case DEFER:
2164 s = string_sprintf("435 Unable to authenticate at present%s",
2165 auth_defer_user_msg);
2166 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2167 set_id, auth_defer_msg);
2168 break;
2169
2170 case BAD64:
2171 s = ss = US"501 Invalid base64 data";
2172 break;
2173
2174 case CANCELLED:
2175 s = ss = US"501 Authentication cancelled";
2176 break;
2177
2178 case UNEXPECTED:
2179 s = ss = US"553 Initial data not expected";
2180 break;
2181
2182 case FAIL:
2183 s = US"535 Incorrect authentication data";
2184 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2185 break;
2186
2187 default:
2188 s = US"435 Internal error";
2189 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2190 "check", set_id, c);
2191 break;
2192 }
2193
2194 smtp_printf("%s\r\n", s);
2195 if (c != OK)
2196 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2197 au->name, host_and_ident(FALSE), ss);
2198
2199 break; /* AUTH_CMD */
2200
2201 /* The HELO/EHLO commands are permitted to appear in the middle of a
2202 session as well as at the beginning. They have the effect of a reset in
2203 addition to their other functions. Their absence at the start cannot be
2204 taken to be an error.
2205
2206 RFC 2821 says:
2207
2208 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2209 or 502 failure replies MUST be returned as appropriate. The SMTP
2210 server MUST stay in the same state after transmitting these replies
2211 that it was in before the EHLO was received.
2212
2213 Therefore, we do not do the reset until after checking the command for
2214 acceptability. This change was made for Exim release 4.11. Previously
2215 it did the reset first. */
2216
2217 case HELO_CMD:
2218 hello = US"HELO";
2219 esmtp = FALSE;
2220 goto HELO_EHLO;
2221
2222 case EHLO_CMD:
2223 hello = US"EHLO";
2224 esmtp = TRUE;
2225
2226 HELO_EHLO: /* Common code for HELO and EHLO */
2227 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2228 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2229
2230 /* Reject the HELO if its argument was invalid or non-existent. A
2231 successful check causes the argument to be saved in malloc store. */
2232
2233 if (!check_helo(smtp_data))
2234 {
2235 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2236
2237 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2238 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2239 (*smtp_data == 0)? US"(no argument given)" :
2240 string_printing(smtp_data));
2241
2242 if (++synprot_error_count > smtp_max_synprot_errors)
2243 {
2244 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2245 "syntax or protocol errors (last command was \"%s\")",
2246 host_and_ident(FALSE), cmd_buffer);
2247 done = 1;
2248 }
2249
2250 break;
2251 }
2252
2253 /* If sender_host_unknown is true, we have got here via the -bs interface,
2254 not called from inetd. Otherwise, we are running an IP connection and the
2255 host address will be set. If the helo name is the primary name of this
2256 host and we haven't done a reverse lookup, force one now. If helo_required
2257 is set, ensure that the HELO name matches the actual host. If helo_verify
2258 is set, do the same check, but softly. */
2259
2260 if (!sender_host_unknown)
2261 {
2262 BOOL old_helo_verified = helo_verified;
2263 uschar *p = smtp_data;
2264
2265 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2266 *p = 0;
2267
2268 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2269 because otherwise the log can be confusing. */
2270
2271 if (sender_host_name == NULL &&
2272 (deliver_domain = sender_helo_name, /* set $domain */
2273 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2274 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2275 (void)host_name_lookup();
2276
2277 /* Rebuild the fullhost info to include the HELO name (and the real name
2278 if it was looked up.) */
2279
2280 host_build_sender_fullhost(); /* Rebuild */
2281 set_process_info("handling%s incoming connection from %s",
2282 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2283
2284 /* Verify if configured. This doesn't give much security, but it does
2285 make some people happy to be able to do it. Note that HELO is legitimately
2286 allowed to quote an address literal. Allow for IPv6 ::ffff: literals. */
2287
2288 helo_verified = FALSE;
2289 if (helo_required || helo_verify)
2290 {
2291 BOOL tempfail = FALSE;
2292
2293 HDEBUG(D_receive) debug_printf("verifying %s %s\n", hello,
2294 sender_helo_name);
2295 if (sender_helo_name[0] == '[')
2296 {
2297 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2298 Ustrlen(sender_host_address)) == 0;
2299
2300 #if HAVE_IPV6
2301 if (!helo_verified)
2302 {
2303 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2304 helo_verified = Ustrncmp(sender_helo_name + 1,
2305 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2306 }
2307 #endif
2308
2309 HDEBUG(D_receive)
2310 { if (helo_verified) debug_printf("matched host address\n"); }
2311 }
2312
2313 /* Do a reverse lookup if one hasn't already given a positive or
2314 negative response. If that fails, or the name doesn't match, try
2315 checking with a forward lookup. */
2316
2317 else
2318 {
2319 if (sender_host_name == NULL && !host_lookup_failed)
2320 tempfail = host_name_lookup() == DEFER;
2321
2322 /* If a host name is known, check it and all its aliases. */
2323
2324 if (sender_host_name != NULL)
2325 {
2326 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2327
2328 if (helo_verified)
2329 {
2330 HDEBUG(D_receive) debug_printf("matched host name\n");
2331 }
2332 else
2333 {
2334 uschar **aliases = sender_host_aliases;
2335 while (*aliases != NULL)
2336 {
2337 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2338 if (helo_verified) break;
2339 }
2340 HDEBUG(D_receive)
2341 {
2342 if (helo_verified)
2343 debug_printf("matched alias %s\n", *(--aliases));
2344 }
2345 }
2346 }
2347
2348 /* Final attempt: try a forward lookup of the helo name */
2349
2350 if (!helo_verified)
2351 {
2352 int rc;
2353 host_item h;
2354 h.name = sender_helo_name;
2355 h.address = NULL;
2356 h.mx = MX_NONE;
2357 h.next = NULL;
2358 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2359 sender_helo_name);
2360 rc = host_find_byname(&h, NULL, NULL, TRUE);
2361 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2362 {
2363 host_item *hh = &h;
2364 while (hh != NULL)
2365 {
2366 if (Ustrcmp(hh->address, sender_host_address) == 0)
2367 {
2368 helo_verified = TRUE;
2369 HDEBUG(D_receive)
2370 debug_printf("IP address for %s matches calling address\n",
2371 sender_helo_name);
2372 break;
2373 }
2374 hh = hh->next;
2375 }
2376 }
2377 }
2378 }
2379
2380 /* Verification failed. A temporary lookup failure gives a temporary
2381 error. */
2382
2383 if (!helo_verified)
2384 {
2385 if (helo_required)
2386 {
2387 smtp_printf("%d %s argument does not match calling host\r\n",
2388 tempfail? 451 : 550, hello);
2389 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2390 tempfail? "temporarily " : "",
2391 hello, sender_helo_name, host_and_ident(FALSE));
2392 helo_verified = old_helo_verified;
2393 break; /* End of HELO/EHLO processing */
2394 }
2395 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2396 "helo_try_verify_hosts\n", hello);
2397 }
2398 }
2399 }
2400
2401 #ifdef EXPERIMENTAL_SPF
2402 /* set up SPF context */
2403 spf_init(sender_helo_name, sender_host_address);
2404 #endif
2405
2406 /* Apply an ACL check if one is defined */
2407
2408 if (acl_smtp_helo != NULL)
2409 {
2410 rc = acl_check(ACL_WHERE_HELO, smtp_data, acl_smtp_helo, &user_msg,
2411 &log_msg);
2412 if (rc != OK)
2413 {
2414 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2415 sender_helo_name = NULL;
2416 host_build_sender_fullhost(); /* Rebuild */
2417 break;
2418 }
2419 }
2420
2421 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2422 abandoning any previous message. */
2423
2424 received_protocol = (esmtp?
2425 protocols[pextend +
2426 ((sender_host_authenticated != NULL)? pauthed : 0) +
2427 ((tls_active >= 0)? pcrpted : 0)]
2428 :
2429 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2430 +
2431 ((sender_host_address != NULL)? pnlocal : 0);
2432
2433 smtp_reset(reset_point);
2434 toomany = FALSE;
2435
2436 /* Generate an OK reply, including the ident if present, and also
2437 the IP address if present. Reflecting back the ident is intended
2438 as a deterrent to mail forgers. For maximum efficiency, and also
2439 because some broken systems expect each response to be in a single
2440 packet, arrange that it is sent in one write(). */
2441
2442 auth_advertised = FALSE;
2443 pipelining_advertised = FALSE;
2444 #ifdef SUPPORT_TLS
2445 tls_advertised = FALSE;
2446 #endif
2447
2448 s = string_sprintf("250 %s Hello %s%s%s",
2449 smtp_active_hostname,
2450 (sender_ident == NULL)? US"" : sender_ident,
2451 (sender_ident == NULL)? US"" : US" at ",
2452 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2453
2454 ptr = Ustrlen(s);
2455 size = ptr + 1;
2456
2457 if (sender_host_address != NULL)
2458 {
2459 s = string_cat(s, &size, &ptr, US" [", 2);
2460 s = string_cat(s, &size, &ptr, sender_host_address,
2461 Ustrlen(sender_host_address));
2462 s = string_cat(s, &size, &ptr, US"]", 1);
2463 }
2464
2465 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2466
2467 /* If we received EHLO, we must create a multiline response which includes
2468 the functions supported. */
2469
2470 if (esmtp)
2471 {
2472 s[3] = '-';
2473
2474 /* I'm not entirely happy with this, as an MTA is supposed to check
2475 that it has enough room to accept a message of maximum size before
2476 it sends this. However, there seems little point in not sending it.
2477 The actual size check happens later at MAIL FROM time. By postponing it
2478 till then, VRFY and EXPN can be used after EHLO when space is short. */
2479
2480 if (thismessage_size_limit > 0)
2481 {
2482 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2483 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2484 }
2485 else
2486 {
2487 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2488 }
2489
2490 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2491 clean; if it has an 8-bit character in its hand, it just sends it. It
2492 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2493 However, some users want this option simply in order to stop MUAs
2494 mangling messages that contain top-bit-set characters. It is therefore
2495 provided as an option. */
2496
2497 if (accept_8bitmime)
2498 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2499
2500 /* Advertise ETRN if there's an ACL checking whether a host is
2501 permitted to issue it; a check is made when any host actually tries. */
2502
2503 if (acl_smtp_etrn != NULL)
2504 {
2505 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2506 }
2507
2508 /* Advertise EXPN if there's an ACL checking whether a host is
2509 permitted to issue it; a check is made when any host actually tries. */
2510
2511 if (acl_smtp_expn != NULL)
2512 {
2513 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2514 }
2515
2516 /* Exim is quite happy with pipelining, so let the other end know that
2517 it is safe to use it, unless advertising is disabled. */
2518
2519 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2520 {
2521 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2522 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2523 pipelining_advertised = TRUE;
2524 }
2525
2526 /* If any server authentication mechanisms are configured, advertise
2527 them if the current host is in auth_advertise_hosts. The problem with
2528 advertising always is that some clients then require users to
2529 authenticate (and aren't configurable otherwise) even though it may not
2530 be necessary (e.g. if the host is in host_accept_relay).
2531
2532 RFC 2222 states that SASL mechanism names contain only upper case
2533 letters, so output the names in upper case, though we actually recognize
2534 them in either case in the AUTH command. */
2535
2536 if (auths != NULL)
2537 {
2538 if (verify_check_host(&auth_advertise_hosts) == OK)
2539 {
2540 auth_instance *au;
2541 BOOL first = TRUE;
2542 for (au = auths; au != NULL; au = au->next)
2543 {
2544 if (au->server && (au->advertise_condition == NULL ||
2545 expand_check_condition(au->advertise_condition, au->name,
2546 US"authenticator")))
2547 {
2548 int saveptr;
2549 if (first)
2550 {
2551 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2552 first = FALSE;
2553 auth_advertised = TRUE;
2554 }
2555 saveptr = ptr;
2556 s = string_cat(s, &size, &ptr, US" ", 1);
2557 s = string_cat(s, &size, &ptr, au->public_name,
2558 Ustrlen(au->public_name));
2559 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2560 au->advertised = TRUE;
2561 }
2562 else au->advertised = FALSE;
2563 }
2564 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2565 }
2566 }
2567
2568 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2569 if it has been included in the binary, and the host matches
2570 tls_advertise_hosts. We must *not* advertise if we are already in a
2571 secure connection. */
2572
2573 #ifdef SUPPORT_TLS
2574 if (tls_active < 0 &&
2575 verify_check_host(&tls_advertise_hosts) != FAIL)
2576 {
2577 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2578 tls_advertised = TRUE;
2579 }
2580 #endif
2581
2582 /* Finish off the multiline reply with one that is always available. */
2583
2584 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2585 }
2586
2587 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2588 has been seen. */
2589
2590 s[ptr] = 0;
2591
2592 #ifdef SUPPORT_TLS
2593 if (tls_active >= 0) (void)tls_write(s, ptr); else
2594 #endif
2595
2596 (void)fwrite(s, 1, ptr, smtp_out);
2597 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2598 helo_seen = TRUE;
2599 break; /* HELO/EHLO */
2600
2601
2602 /* The MAIL command requires an address as an operand. All we do
2603 here is to parse it for syntactic correctness. The form "<>" is
2604 a special case which converts into an empty string. The start/end
2605 pointers in the original are not used further for this address, as
2606 it is the canonical extracted address which is all that is kept. */
2607
2608 case MAIL_CMD:
2609 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2610 was_rej_mail = TRUE; /* Reset if accepted */
2611
2612 if (helo_required && !helo_seen)
2613 {
2614 smtp_printf("503 HELO or EHLO required\r\n");
2615 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2616 "HELO/EHLO given", host_and_ident(FALSE));
2617 break;
2618 }
2619
2620 if (sender_address != NULL)
2621 {
2622 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2623 US"sender already given");
2624 break;
2625 }
2626
2627 if (smtp_data[0] == 0)
2628 {
2629 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2630 US"MAIL must have an address operand");
2631 break;
2632 }
2633
2634 /* Check to see if the limit for messages per connection would be
2635 exceeded by accepting further messages. */
2636
2637 if (smtp_accept_max_per_connection > 0 &&
2638 smtp_mailcmd_count > smtp_accept_max_per_connection)
2639 {
2640 smtp_printf("421 too many messages in this connection\r\n");
2641 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2642 "messages in one connection", host_and_ident(TRUE));
2643 break;
2644 }
2645
2646 /* Reset for start of message - even if this is going to fail, we
2647 obviously need to throw away any previous data. */
2648
2649 smtp_reset(reset_point);
2650 toomany = FALSE;
2651 sender_data = recipient_data = NULL;
2652
2653 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2654
2655 if (esmtp) for(;;)
2656 {
2657 uschar *name, *value, *end;
2658 unsigned long int size;
2659
2660 if (!extract_option(&name, &value)) break;
2661
2662 /* Handle SIZE= by reading the value. We don't do the check till later,
2663 in order to be able to log the sender address on failure. */
2664
2665 if (strcmpic(name, US"SIZE") == 0 &&
2666 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2667 {
2668 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2669 size = INT_MAX;
2670 message_size = (int)size;
2671 }
2672
2673 /* If this session was initiated with EHLO and accept_8bitmime is set,
2674 Exim will have indicated that it supports the BODY=8BITMIME option. In
2675 fact, it does not support this according to the RFCs, in that it does not
2676 take any special action for forwarding messages containing 8-bit
2677 characters. That is why accept_8bitmime is not the default setting, but
2678 some sites want the action that is provided. We recognize both "8BITMIME"
2679 and "7BIT" as body types, but take no action. */
2680
2681 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2682 (strcmpic(value, US"8BITMIME") == 0 ||
2683 strcmpic(value, US"7BIT") == 0)) {}
2684
2685 /* Handle the AUTH extension. If the value given is not "<>" and either
2686 the ACL says "yes" or there is no ACL but the sending host is
2687 authenticated, we set it up as the authenticated sender. However, if the
2688 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2689 the condition is met. The value of AUTH is an xtext, which means that +,
2690 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2691 coding. */
2692
2693 else if (strcmpic(name, US"AUTH") == 0)
2694 {
2695 if (Ustrcmp(value, "<>") != 0)
2696 {
2697 int rc;
2698 uschar *ignore_msg;
2699
2700 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2701 {
2702 /* Put back terminator overrides for error message */
2703 name[-1] = ' ';
2704 value[-1] = '=';
2705 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2706 US"invalid data for AUTH");
2707 goto COMMAND_LOOP;
2708 }
2709
2710 if (acl_smtp_mailauth == NULL)
2711 {
2712 ignore_msg = US"client not authenticated";
2713 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2714 }
2715 else
2716 {
2717 ignore_msg = US"rejected by ACL";
2718 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2719 &user_msg, &log_msg);
2720 }
2721
2722 switch (rc)
2723 {
2724 case OK:
2725 if (authenticated_by == NULL ||
2726 authenticated_by->mail_auth_condition == NULL ||
2727 expand_check_condition(authenticated_by->mail_auth_condition,
2728 authenticated_by->name, US"authenticator"))
2729 break; /* Accept the AUTH */
2730
2731 ignore_msg = US"server_mail_auth_condition failed";
2732 if (authenticated_id != NULL)
2733 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2734 ignore_msg, authenticated_id);
2735
2736 /* Fall through */
2737
2738 case FAIL:
2739 authenticated_sender = NULL;
2740 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2741 value, host_and_ident(TRUE), ignore_msg);
2742 break;
2743
2744 /* Should only get DEFER or ERROR here. Put back terminator
2745 overrides for error message */
2746
2747 default:
2748 name[-1] = ' ';
2749 value[-1] = '=';
2750 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2751 log_msg);
2752 goto COMMAND_LOOP;
2753 }
2754 }
2755 }
2756
2757 /* Unknown option. Stick back the terminator characters and break
2758 the loop. An error for a malformed address will occur. */
2759
2760 else
2761 {
2762 name[-1] = ' ';
2763 value[-1] = '=';
2764 break;
2765 }
2766 }
2767
2768 /* If we have passed the threshold for rate limiting, apply the current
2769 delay, and update it for next time, provided this is a limited host. */
2770
2771 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2772 verify_check_host(&smtp_ratelimit_hosts) == OK)
2773 {
2774 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2775 smtp_delay_mail/1000.0);
2776 millisleep((int)smtp_delay_mail);
2777 smtp_delay_mail *= smtp_rlm_factor;
2778 if (smtp_delay_mail > (double)smtp_rlm_limit)
2779 smtp_delay_mail = (double)smtp_rlm_limit;
2780 }
2781
2782 /* Now extract the address, first applying any SMTP-time rewriting. The
2783 TRUE flag allows "<>" as a sender address. */
2784
2785 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2786 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2787 global_rewrite_rules) : smtp_data;
2788
2789 /* rfc821_domains = TRUE; << no longer needed */
2790 raw_sender =
2791 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2792 TRUE);
2793 /* rfc821_domains = FALSE; << no longer needed */
2794
2795 if (raw_sender == NULL)
2796 {
2797 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2798 break;
2799 }
2800
2801 sender_address = raw_sender;
2802
2803 /* If there is a configured size limit for mail, check that this message
2804 doesn't exceed it. The check is postponed to this point so that the sender
2805 can be logged. */
2806
2807 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2808 {
2809 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2810 log_write(L_size_reject,
2811 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2812 "message too big: size%s=%d max=%d",
2813 sender_address,
2814 host_and_ident(TRUE),
2815 (message_size == INT_MAX)? ">" : "",
2816 message_size,
2817 thismessage_size_limit);
2818 sender_address = NULL;
2819 break;
2820 }
2821
2822 /* Check there is enough space on the disk unless configured not to.
2823 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2824 plus the current message - i.e. we accept the message only if it won't
2825 reduce the space below the threshold. Add 5000 to the size to allow for
2826 overheads such as the Received: line and storing of recipients, etc.
2827 By putting the check here, even when SIZE is not given, it allow VRFY
2828 and EXPN etc. to be used when space is short. */
2829
2830 if (!receive_check_fs(
2831 (smtp_check_spool_space && message_size >= 0)?
2832 message_size + 5000 : 0))
2833 {
2834 smtp_printf("452 Space shortage, please try later\r\n");
2835 sender_address = NULL;
2836 break;
2837 }
2838
2839 /* If sender_address is unqualified, reject it, unless this is a locally
2840 generated message, or the sending host or net is permitted to send
2841 unqualified addresses - typically local machines behaving as MUAs -
2842 in which case just qualify the address. The flag is set above at the start
2843 of the SMTP connection. */
2844
2845 if (sender_domain == 0 && sender_address[0] != 0)
2846 {
2847 if (allow_unqualified_sender)
2848 {
2849 sender_domain = Ustrlen(sender_address) + 1;
2850 sender_address = rewrite_address_qualify(sender_address, FALSE);
2851 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2852 raw_sender);
2853 }
2854 else
2855 {
2856 smtp_printf("501 %s: sender address must contain a domain\r\n",
2857 smtp_data);
2858 log_write(L_smtp_syntax_error,
2859 LOG_MAIN|LOG_REJECT,
2860 "unqualified sender rejected: <%s> %s%s",
2861 raw_sender,
2862 host_and_ident(TRUE),
2863 host_lookup_msg);
2864 sender_address = NULL;
2865 break;
2866 }
2867 }
2868
2869 /* Apply an ACL check if one is defined, before responding */
2870
2871 rc = (acl_smtp_mail == NULL)? OK :
2872 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2873
2874 if (rc == OK || rc == DISCARD)
2875 {
2876 smtp_printf("250 OK\r\n");
2877 smtp_delay_rcpt = smtp_rlr_base;
2878 recipients_discarded = (rc == DISCARD);
2879 was_rej_mail = FALSE;
2880 }
2881
2882 else
2883 {
2884 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2885 sender_address = NULL;
2886 }
2887 break;
2888
2889
2890 /* The RCPT command requires an address as an operand. All we do
2891 here is to parse it for syntactic correctness. There may be any number
2892 of RCPT commands, specifying multiple senders. We build them all into
2893 a data structure that is in argc/argv format. The start/end values
2894 given by parse_extract_address are not used, as we keep only the
2895 extracted address. */
2896
2897 case RCPT_CMD:
2898 rcpt_count++;
2899 was_rcpt = TRUE;
2900
2901 /* There must be a sender address; if the sender was rejected and
2902 pipelining was advertised, we assume the client was pipelining, and do not
2903 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2904 get the same treatment. */
2905
2906 if (sender_address == NULL)
2907 {
2908 if (pipelining_advertised && last_was_rej_mail)
2909 {
2910 smtp_printf("503 sender not yet given\r\n");
2911 was_rej_mail = TRUE;
2912 }
2913 else
2914 {
2915 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2916 US"sender not yet given");
2917 was_rcpt = FALSE; /* Not a valid RCPT */
2918 }
2919 rcpt_fail_count++;
2920 break;
2921 }
2922
2923 /* Check for an operand */
2924
2925 if (smtp_data[0] == 0)
2926 {
2927 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2928 US"RCPT must have an address operand");
2929 rcpt_fail_count++;
2930 break;
2931 }
2932
2933 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2934 as a recipient address */
2935
2936 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2937 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2938 global_rewrite_rules) : smtp_data;
2939
2940 /* rfc821_domains = TRUE; << no longer needed */
2941 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2942 &recipient_domain, FALSE);
2943 /* rfc821_domains = FALSE; << no longer needed */
2944
2945 if (recipient == NULL)
2946 {
2947 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2948 rcpt_fail_count++;
2949 break;
2950 }
2951
2952 /* If the recipient address is unqualified, reject it, unless this is a
2953 locally generated message. However, unqualified addresses are permitted
2954 from a configured list of hosts and nets - typically when behaving as
2955 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2956 really. The flag is set at the start of the SMTP connection.
2957
2958 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2959 assumed this meant "reserved local part", but the revision of RFC 821 and
2960 friends now makes it absolutely clear that it means *mailbox*. Consequently
2961 we must always qualify this address, regardless. */
2962
2963 if (recipient_domain == 0)
2964 {
2965 if (allow_unqualified_recipient ||
2966 strcmpic(recipient, US"postmaster") == 0)
2967 {
2968 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2969 recipient);
2970 recipient_domain = Ustrlen(recipient) + 1;
2971 recipient = rewrite_address_qualify(recipient, TRUE);
2972 }
2973 else
2974 {
2975 rcpt_fail_count++;
2976 smtp_printf("501 %s: recipient address must contain a domain\r\n",
2977 smtp_data);
2978 log_write(L_smtp_syntax_error,
2979 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
2980 "<%s> %s%s", recipient, host_and_ident(TRUE),
2981 host_lookup_msg);
2982 break;
2983 }
2984 }
2985
2986 /* Check maximum allowed */
2987
2988 if (rcpt_count > recipients_max && recipients_max > 0)
2989 {
2990 if (recipients_max_reject)
2991 {
2992 rcpt_fail_count++;
2993 smtp_printf("552 too many recipients\r\n");
2994 if (!toomany)
2995 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
2996 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
2997 }
2998 else
2999 {
3000 rcpt_defer_count++;
3001 smtp_printf("452 too many recipients\r\n");
3002 if (!toomany)
3003 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3004 "temporarily rejected: sender=<%s> %s", sender_address,
3005 host_and_ident(TRUE));
3006 }
3007
3008 toomany = TRUE;
3009 break;
3010 }
3011
3012 /* If we have passed the threshold for rate limiting, apply the current
3013 delay, and update it for next time, provided this is a limited host. */
3014
3015 if (rcpt_count > smtp_rlr_threshold &&
3016 verify_check_host(&smtp_ratelimit_hosts) == OK)
3017 {
3018 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3019 smtp_delay_rcpt/1000.0);
3020 millisleep((int)smtp_delay_rcpt);
3021 smtp_delay_rcpt *= smtp_rlr_factor;
3022 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3023 smtp_delay_rcpt = (double)smtp_rlr_limit;
3024 }
3025
3026 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3027 for them. Otherwise, check the access control list for this recipient. */
3028
3029 rc = recipients_discarded? DISCARD :
3030 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3031
3032 /* The ACL was happy */
3033
3034 if (rc == OK)
3035 {
3036 smtp_printf("250 Accepted\r\n");
3037 receive_add_recipient(recipient, -1);
3038 }
3039
3040 /* The recipient was discarded */
3041
3042 else if (rc == DISCARD)
3043 {
3044 smtp_printf("250 Accepted\r\n");
3045 rcpt_fail_count++;
3046 discarded = TRUE;
3047 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3048 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3049 (sender_address_unrewritten != NULL)?
3050 sender_address_unrewritten : sender_address,
3051 smtp_data, recipients_discarded? "MAIL" : "RCPT",
3052 (log_msg == NULL)? US"" : US": ",
3053 (log_msg == NULL)? US"" : log_msg);
3054 }
3055
3056 /* Either the ACL failed the address, or it was deferred. */
3057
3058 else
3059 {
3060 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3061 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3062 }
3063 break;
3064
3065
3066 /* The DATA command is legal only if it follows successful MAIL FROM
3067 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3068 not counted as a protocol error if it follows RCPT (which must have been
3069 rejected if there are no recipients.) This function is complete when a
3070 valid DATA command is encountered.
3071
3072 Note concerning the code used: RFC 2821 says this:
3073
3074 - If there was no MAIL, or no RCPT, command, or all such commands
3075 were rejected, the server MAY return a "command out of sequence"
3076 (503) or "no valid recipients" (554) reply in response to the
3077 DATA command.
3078
3079 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3080 because it is the same whether pipelining is in use or not. */
3081
3082 case DATA_CMD:
3083 if (!discarded && recipients_count <= 0)
3084 {
3085 if (pipelining_advertised && last_was_rcpt)
3086 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3087 else
3088 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3089 US"valid RCPT command must precede DATA");
3090 break;
3091 }
3092
3093 if (toomany && recipients_max_reject)
3094 {
3095 sender_address = NULL; /* This will allow a new MAIL without RSET */
3096 sender_address_unrewritten = NULL;
3097 smtp_printf("554 Too many recipients\r\n");
3098 break;
3099 }
3100
3101 if (acl_smtp_predata == NULL) rc = OK; else
3102 {
3103 enable_dollar_recipients = TRUE;
3104 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3105 &log_msg);
3106 enable_dollar_recipients = FALSE;
3107 }
3108
3109 if (rc == OK)
3110 {
3111 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3112 done = 3;
3113 message_ended = END_NOTENDED; /* Indicate in middle of data */
3114 }
3115
3116 /* Either the ACL failed the address, or it was deferred. */
3117
3118 else
3119 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3120
3121 break;
3122
3123
3124 case VRFY_CMD:
3125 rc = acl_check(ACL_WHERE_VRFY, smtp_data, acl_smtp_vrfy, &user_msg,
3126 &log_msg);
3127 if (rc != OK)
3128 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3129 else
3130 {
3131 uschar *address;
3132 uschar *s = NULL;
3133
3134 /* rfc821_domains = TRUE; << no longer needed */
3135 address = parse_extract_address(smtp_data, &errmess, &start, &end,
3136 &recipient_domain, FALSE);
3137 /* rfc821_domains = FALSE; << no longer needed */
3138
3139 if (address == NULL)
3140 s = string_sprintf("501 %s", errmess);
3141 else
3142 {
3143 address_item *addr = deliver_make_addr(address, FALSE);
3144 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3145 -1, -1, NULL, NULL, NULL))
3146 {
3147 case OK:
3148 s = string_sprintf("250 <%s> is deliverable", address);
3149 break;
3150
3151 case DEFER:
3152 s = (addr->message != NULL)?
3153 string_sprintf("451 <%s> %s", address, addr->message) :
3154 string_sprintf("451 Cannot resolve <%s> at this time", address);
3155 break;
3156
3157 case FAIL:
3158 s = (addr->message != NULL)?
3159 string_sprintf("550 <%s> %s", address, addr->message) :
3160 string_sprintf("550 <%s> is not deliverable", address);
3161 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3162 smtp_data, host_and_ident(TRUE));
3163 break;
3164 }
3165 }
3166
3167 smtp_printf("%s\r\n", s);
3168 }
3169 break;
3170
3171
3172 case EXPN_CMD:
3173 rc = acl_check(ACL_WHERE_EXPN, smtp_data, acl_smtp_expn, &user_msg,
3174 &log_msg);
3175 if (rc != OK)
3176 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3177 else
3178 {
3179 BOOL save_log_testing_mode = log_testing_mode;
3180 address_test_mode = log_testing_mode = TRUE;
3181 (void) verify_address(deliver_make_addr(smtp_data, FALSE), smtp_out,
3182 vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1, NULL, NULL,
3183 NULL);
3184 address_test_mode = FALSE;
3185 log_testing_mode = save_log_testing_mode; /* true for -bh */
3186 }
3187 break;
3188
3189
3190 #ifdef SUPPORT_TLS
3191
3192 case STARTTLS_CMD:
3193 if (!tls_advertised)
3194 {
3195 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3196 US"STARTTLS command used when not advertised");
3197 break;
3198 }
3199
3200 /* Apply an ACL check if one is defined */
3201
3202 if (acl_smtp_starttls != NULL)
3203 {
3204 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3205 &log_msg);
3206 if (rc != OK)
3207 {
3208 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3209 break;
3210 }
3211 }
3212
3213 /* RFC 2487 is not clear on when this command may be sent, though it
3214 does state that all information previously obtained from the client
3215 must be discarded if a TLS session is started. It seems reasonble to
3216 do an implied RSET when STARTTLS is received. */
3217
3218 incomplete_transaction_log(US"STARTTLS");
3219 smtp_reset(reset_point);
3220 toomany = FALSE;
3221 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3222
3223 /* Attempt to start up a TLS session, and if successful, discard all
3224 knowledge that was obtained previously. At least, that's what the RFC says,
3225 and that's what happens by default. However, in order to work round YAEB,
3226 there is an option to remember the esmtp state. Sigh.
3227
3228 We must allow for an extra EHLO command and an extra AUTH command after
3229 STARTTLS that don't add to the nonmail command count. */
3230
3231 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3232 {
3233 if (!tls_remember_esmtp)
3234 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3235 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3236 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3237 if (sender_helo_name != NULL)
3238 {
3239 store_free(sender_helo_name);
3240 sender_helo_name = NULL;
3241 host_build_sender_fullhost(); /* Rebuild */
3242 set_process_info("handling incoming TLS connection from %s",
3243 host_and_ident(FALSE));
3244 }
3245 received_protocol = (esmtp?
3246 protocols[pextend + pcrpted +
3247 ((sender_host_authenticated != NULL)? pauthed : 0)]
3248 :
3249 protocols[pnormal + pcrpted])
3250 +
3251 ((sender_host_address != NULL)? pnlocal : 0);
3252
3253 sender_host_authenticated = NULL;
3254 authenticated_id = NULL;
3255 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3256 DEBUG(D_tls) debug_printf("TLS active\n");
3257 break; /* Successful STARTTLS */
3258 }
3259
3260 /* Some local configuration problem was discovered before actually trying
3261 to do a TLS handshake; give a temporary error. */
3262
3263 else if (rc == DEFER)
3264 {
3265 smtp_printf("454 TLS currently unavailable\r\n");
3266 break;
3267 }
3268
3269 /* Hard failure. Reject everything except QUIT or closed connection. One
3270 cause for failure is a nested STARTTLS, in which case tls_active remains
3271 set, but we must still reject all incoming commands. */
3272
3273 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3274 while (done <= 0)
3275 {
3276 switch(smtp_read_command(FALSE))
3277 {
3278 case EOF_CMD:
3279 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3280 smtp_get_connection_info());
3281 done = 2;
3282 break;
3283
3284 case QUIT_CMD:
3285 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3286 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3287 smtp_get_connection_info());
3288 done = 2;
3289 break;
3290
3291 default:
3292 smtp_printf("554 Security failure\r\n");
3293 break;
3294 }
3295 }
3296 tls_close(TRUE);
3297 break;
3298 #endif
3299
3300
3301 /* The ACL for QUIT is provided for gathering statistical information or
3302 similar; it does not affect the response code, but it can supply a custom
3303 message. */
3304
3305 case QUIT_CMD:
3306 incomplete_transaction_log(US"QUIT");
3307
3308 if (acl_smtp_quit != NULL)
3309 {
3310 rc = acl_check(ACL_WHERE_QUIT, US"", acl_smtp_quit,&user_msg,&log_msg);
3311 if (rc == ERROR)
3312 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3313 log_msg);
3314 }
3315 else user_msg = NULL;
3316
3317 if (user_msg == NULL)
3318 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3319 else
3320 smtp_printf("221 %s\r\n", user_msg);
3321
3322 #ifdef SUPPORT_TLS
3323 tls_close(TRUE);
3324 #endif
3325
3326 done = 2;
3327 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3328 smtp_get_connection_info());
3329 break;
3330
3331
3332 case RSET_CMD:
3333 incomplete_transaction_log(US"RSET");
3334 smtp_reset(reset_point);
3335 toomany = FALSE;
3336 smtp_printf("250 Reset OK\r\n");
3337 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3338 break;
3339
3340
3341 case NOOP_CMD:
3342 smtp_printf("250 OK\r\n");
3343 break;
3344
3345
3346 /* Show ETRN/EXPN/VRFY if there's
3347 an ACL for checking hosts; if actually used, a check will be done for
3348 permitted hosts. */
3349
3350 case HELP_CMD:
3351 smtp_printf("214-Commands supported:\r\n");
3352 {
3353 uschar buffer[256];
3354 buffer[0] = 0;
3355 Ustrcat(buffer, " AUTH");
3356 #ifdef SUPPORT_TLS
3357 Ustrcat(buffer, " STARTTLS");
3358 #endif
3359 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3360 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3361 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3362 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3363 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3364 smtp_printf("214%s\r\n", buffer);
3365 }
3366 break;
3367
3368
3369 case EOF_CMD:
3370 incomplete_transaction_log(US"connection lost");
3371 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3372
3373 /* Don't log by default unless in the middle of a message, as some mailers
3374 just drop the call rather than sending QUIT, and it clutters up the logs.
3375 */
3376
3377 if (sender_address != NULL || recipients_count > 0)
3378 log_write(L_lost_incoming_connection,
3379 LOG_MAIN,
3380 "unexpected %s while reading SMTP command from %s%s",
3381 sender_host_unknown? "EOF" : "disconnection",
3382 host_and_ident(FALSE), smtp_read_error);
3383
3384 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3385 smtp_get_connection_info(), smtp_read_error);
3386
3387 done = 1;
3388 break;
3389
3390
3391 case ETRN_CMD:
3392 if (sender_address != NULL)
3393 {
3394 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3395 US"ETRN is not permitted inside a transaction");
3396 break;
3397 }
3398
3399 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_data,
3400 host_and_ident(FALSE));
3401
3402 rc = acl_check(ACL_WHERE_ETRN, smtp_data, acl_smtp_etrn, &user_msg,
3403 &log_msg);
3404 if (rc != OK)
3405 {
3406 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3407 break;
3408 }
3409
3410 /* Compute the serialization key for this command. */
3411
3412 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_data);
3413
3414 /* If a command has been specified for running as a result of ETRN, we
3415 permit any argument to ETRN. If not, only the # standard form is permitted,
3416 since that is strictly the only kind of ETRN that can be implemented
3417 according to the RFC. */
3418
3419 if (smtp_etrn_command != NULL)
3420 {
3421 uschar *error;
3422 BOOL rc;
3423 etrn_command = smtp_etrn_command;
3424 deliver_domain = smtp_data;
3425 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3426 US"ETRN processing", &error);
3427 deliver_domain = NULL;
3428 if (!rc)
3429 {
3430 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3431 error);
3432 smtp_printf("458 Internal failure\r\n");
3433 break;
3434 }
3435 }
3436
3437 /* Else set up to call Exim with the -R option. */
3438
3439 else
3440 {
3441 if (*smtp_data++ != '#')
3442 {
3443 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3444 US"argument must begin with #");
3445 break;
3446 }
3447 etrn_command = US"exim -R";
3448 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3449 smtp_data);
3450 }
3451
3452 /* If we are host-testing, don't actually do anything. */
3453
3454 if (host_checking)
3455 {
3456 HDEBUG(D_any)
3457 {
3458 debug_printf("ETRN command is: %s\n", etrn_command);
3459 debug_printf("ETRN command execution skipped\n");
3460 }
3461 smtp_printf("250 OK\r\n");
3462 break;
3463 }
3464
3465
3466 /* If ETRN queue runs are to be serialized, check the database to
3467 ensure one isn't already running. */
3468
3469 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3470 {
3471 smtp_printf("458 Already processing %s\r\n", smtp_data);
3472 break;
3473 }
3474
3475 /* Fork a child process and run the command. We don't want to have to
3476 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3477 forking. It should be set that way anyway for external incoming SMTP,
3478 but we save and restore to be tidy. If serialization is required, we
3479 actually run the command in yet another process, so we can wait for it
3480 to complete and then remove the serialization lock. */
3481
3482 oldsignal = signal(SIGCHLD, SIG_IGN);
3483
3484 if ((pid = fork()) == 0)
3485 {
3486 smtp_input = FALSE; /* This process is not associated with the */
3487 (void)fclose(smtp_in); /* SMTP call any more. */
3488 (void)fclose(smtp_out);
3489
3490 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3491
3492 /* If not serializing, do the exec right away. Otherwise, fork down
3493 into another process. */
3494
3495 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3496 {
3497 DEBUG(D_exec) debug_print_argv(argv);
3498 exim_nullstd(); /* Ensure std{in,out,err} exist */
3499 execv(CS argv[0], (char *const *)argv);
3500 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3501 etrn_command, strerror(errno));
3502 _exit(EXIT_FAILURE); /* paranoia */
3503 }
3504
3505 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3506 is, we are in the first subprocess, after forking again. All we can do