Make verify=helo do the verification on the fly it if was not done
[exim.git] / src / src / smtp_in.c
1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.22 2005/08/02 15:19:20 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 * Verify HELO argument *
1937 *************************************************/
1938
1939 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
1940 matched. It is also called from ACL processing if verify = helo is used and
1941 verification was not previously tried (i.e. helo_try_verify_hosts was not
1942 matched). The result of its processing is to set helo_verified and
1943 helo_verify_failed. These variables should both be FALSE for this function to
1944 be called.
1945
1946 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
1947 for IPv6 ::ffff: literals.
1948
1949 Argument: none
1950 Returns: TRUE if testing was completed;
1951 FALSE on a temporary failure
1952 */
1953
1954 BOOL
1955 smtp_verify_helo(void)
1956 {
1957 BOOL yield = TRUE;
1958
1959 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
1960 sender_helo_name);
1961
1962 if (sender_helo_name == NULL)
1963 {
1964 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
1965 }
1966
1967 else if (sender_helo_name[0] == '[')
1968 {
1969 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
1970 Ustrlen(sender_host_address)) == 0;
1971
1972 #if HAVE_IPV6
1973 if (!helo_verified)
1974 {
1975 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
1976 helo_verified = Ustrncmp(sender_helo_name + 1,
1977 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
1978 }
1979 #endif
1980
1981 HDEBUG(D_receive)
1982 { if (helo_verified) debug_printf("matched host address\n"); }
1983 }
1984
1985 /* Do a reverse lookup if one hasn't already given a positive or negative
1986 response. If that fails, or the name doesn't match, try checking with a forward
1987 lookup. */
1988
1989 else
1990 {
1991 if (sender_host_name == NULL && !host_lookup_failed)
1992 yield = host_name_lookup() != DEFER;
1993
1994 /* If a host name is known, check it and all its aliases. */
1995
1996 if (sender_host_name != NULL)
1997 {
1998 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
1999
2000 if (helo_verified)
2001 {
2002 HDEBUG(D_receive) debug_printf("matched host name\n");
2003 }
2004 else
2005 {
2006 uschar **aliases = sender_host_aliases;
2007 while (*aliases != NULL)
2008 {
2009 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2010 if (helo_verified) break;
2011 }
2012 HDEBUG(D_receive)
2013 {
2014 if (helo_verified)
2015 debug_printf("matched alias %s\n", *(--aliases));
2016 }
2017 }
2018 }
2019
2020 /* Final attempt: try a forward lookup of the helo name */
2021
2022 if (!helo_verified)
2023 {
2024 int rc;
2025 host_item h;
2026 h.name = sender_helo_name;
2027 h.address = NULL;
2028 h.mx = MX_NONE;
2029 h.next = NULL;
2030 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2031 sender_helo_name);
2032 rc = host_find_byname(&h, NULL, NULL, TRUE);
2033 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2034 {
2035 host_item *hh = &h;
2036 while (hh != NULL)
2037 {
2038 if (Ustrcmp(hh->address, sender_host_address) == 0)
2039 {
2040 helo_verified = TRUE;
2041 HDEBUG(D_receive)
2042 debug_printf("IP address for %s matches calling address\n",
2043 sender_helo_name);
2044 break;
2045 }
2046 hh = hh->next;
2047 }
2048 }
2049 }
2050 }
2051
2052 if (!helo_verified) helo_verify_failed = FALSE; /* We've tried ... */
2053 return yield;
2054 }
2055
2056
2057
2058
2059 /*************************************************
2060 * Initialize for SMTP incoming message *
2061 *************************************************/
2062
2063 /* This function conducts the initial dialogue at the start of an incoming SMTP
2064 message, and builds a list of recipients. However, if the incoming message
2065 is part of a batch (-bS option) a separate function is called since it would
2066 be messy having tests splattered about all over this function. This function
2067 therefore handles the case where interaction is occurring. The input and output
2068 files are set up in smtp_in and smtp_out.
2069
2070 The global recipients_list is set to point to a vector of recipient_item
2071 blocks, whose number is given by recipients_count. This is extended by the
2072 receive_add_recipient() function. The global variable sender_address is set to
2073 the sender's address. The yield is +1 if a message has been successfully
2074 started, 0 if a QUIT command was encountered or the connection was refused from
2075 the particular host, or -1 if the connection was lost.
2076
2077 Argument: none
2078
2079 Returns: > 0 message successfully started (reached DATA)
2080 = 0 QUIT read or end of file reached or call refused
2081 < 0 lost connection
2082 */
2083
2084 int
2085 smtp_setup_msg(void)
2086 {
2087 int done = 0;
2088 BOOL toomany = FALSE;
2089 BOOL discarded = FALSE;
2090 BOOL last_was_rej_mail = FALSE;
2091 BOOL last_was_rcpt = FALSE;
2092 void *reset_point = store_get(0);
2093
2094 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2095
2096 /* Reset for start of new message. We allow one RSET not to be counted as a
2097 nonmail command, for those MTAs that insist on sending it between every
2098 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2099 TLS between messages (an Exim client may do this if it has messages queued up
2100 for the host). Note: we do NOT reset AUTH at this point. */
2101
2102 smtp_reset(reset_point);
2103 message_ended = END_NOTSTARTED;
2104
2105 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2106 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2107 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2108 #ifdef SUPPORT_TLS
2109 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2110 #endif
2111
2112 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2113
2114 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2115
2116 /* Batched SMTP is handled in a different function. */
2117
2118 if (smtp_batched_input) return smtp_setup_batch_msg();
2119
2120 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2121 value. The values are 2 larger than the required yield of the function. */
2122
2123 while (done <= 0)
2124 {
2125 uschar **argv;
2126 uschar *etrn_command;
2127 uschar *etrn_serialize_key;
2128 uschar *errmess;
2129 uschar *user_msg, *log_msg;
2130 uschar *recipient = NULL;
2131 uschar *hello = NULL;
2132 uschar *set_id = NULL;
2133 uschar *s, *ss;
2134 BOOL was_rej_mail = FALSE;
2135 BOOL was_rcpt = FALSE;
2136 void (*oldsignal)(int);
2137 pid_t pid;
2138 int start, end, sender_domain, recipient_domain;
2139 int ptr, size, rc;
2140 int c;
2141 auth_instance *au;
2142
2143 switch(smtp_read_command(TRUE))
2144 {
2145 /* The AUTH command is not permitted to occur inside a transaction, and may
2146 occur successfully only once per connection, and then only when we've
2147 advertised it. Actually, that isn't quite true. When TLS is started, all
2148 previous information about a connection must be discarded, so a new AUTH is
2149 permitted at that time.
2150
2151 AUTH is initially labelled as a "nonmail command" so that one occurrence
2152 doesn't get counted. We change the label here so that multiple failing
2153 AUTHS will eventually hit the nonmail threshold. */
2154
2155 case AUTH_CMD:
2156 authentication_failed = TRUE;
2157 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2158
2159 if (!auth_advertised)
2160 {
2161 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2162 US"AUTH command used when not advertised");
2163 break;
2164 }
2165 if (sender_host_authenticated != NULL)
2166 {
2167 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2168 US"already authenticated");
2169 break;
2170 }
2171 if (sender_address != NULL)
2172 {
2173 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2174 US"not permitted in mail transaction");
2175 break;
2176 }
2177
2178 /* Check the ACL */
2179
2180 if (acl_smtp_auth != NULL)
2181 {
2182 rc = acl_check(ACL_WHERE_AUTH, smtp_data, acl_smtp_auth, &user_msg,
2183 &log_msg);
2184 if (rc != OK)
2185 {
2186 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2187 break;
2188 }
2189 }
2190
2191 /* Find the name of the requested authentication mechanism. */
2192
2193 s = smtp_data;
2194 while ((c = *smtp_data) != 0 && !isspace(c))
2195 {
2196 if (!isalnum(c) && c != '-' && c != '_')
2197 {
2198 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2199 US"invalid character in authentication mechanism name");
2200 goto COMMAND_LOOP;
2201 }
2202 smtp_data++;
2203 }
2204
2205 /* If not at the end of the line, we must be at white space. Terminate the
2206 name and move the pointer on to any data that may be present. */
2207
2208 if (*smtp_data != 0)
2209 {
2210 *smtp_data++ = 0;
2211 while (isspace(*smtp_data)) smtp_data++;
2212 }
2213
2214 /* Search for an authentication mechanism which is configured for use
2215 as a server and which has been advertised. */
2216
2217 for (au = auths; au != NULL; au = au->next)
2218 {
2219 if (strcmpic(s, au->public_name) == 0 && au->server &&
2220 au->advertised) break;
2221 }
2222
2223 if (au == NULL)
2224 {
2225 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2226 string_sprintf("%s authentication mechanism not supported", s));
2227 break;
2228 }
2229
2230 /* Run the checking code, passing the remainder of the command
2231 line as data. Initialize $0 empty. The authenticator may set up
2232 other numeric variables. Afterwards, have a go at expanding the set_id
2233 string, even if authentication failed - for bad passwords it can be useful
2234 to log the userid. On success, require set_id to expand and exist, and
2235 put it in authenticated_id. Save this in permanent store, as the working
2236 store gets reset at HELO, RSET, etc. */
2237
2238 expand_nmax = 0;
2239 expand_nlength[0] = 0; /* $0 contains nothing */
2240
2241 c = (au->info->servercode)(au, smtp_data);
2242 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2243 expand_nmax = -1; /* Reset numeric variables */
2244
2245 /* The value of authenticated_id is stored in the spool file and printed in
2246 log lines. It must not contain binary zeros or newline characters. In
2247 normal use, it never will, but when playing around or testing, this error
2248 can (did) happen. To guard against this, ensure that the id contains only
2249 printing characters. */
2250
2251 if (set_id != NULL) set_id = string_printing(set_id);
2252
2253 /* For the non-OK cases, set up additional logging data if set_id
2254 is not empty. */
2255
2256 if (c != OK)
2257 {
2258 if (set_id != NULL && *set_id != 0)
2259 set_id = string_sprintf(" (set_id=%s)", set_id);
2260 else set_id = US"";
2261 }
2262
2263 /* Switch on the result */
2264
2265 switch(c)
2266 {
2267 case OK:
2268 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2269 {
2270 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2271 sender_host_authenticated = au->name;
2272 authentication_failed = FALSE;
2273 received_protocol =
2274 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2275 ((sender_host_address != NULL)? pnlocal : 0);
2276 s = ss = US"235 Authentication succeeded";
2277 authenticated_by = au;
2278 break;
2279 }
2280
2281 /* Authentication succeeded, but we failed to expand the set_id string.
2282 Treat this as a temporary error. */
2283
2284 auth_defer_msg = expand_string_message;
2285 /* Fall through */
2286
2287 case DEFER:
2288 s = string_sprintf("435 Unable to authenticate at present%s",
2289 auth_defer_user_msg);
2290 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2291 set_id, auth_defer_msg);
2292 break;
2293
2294 case BAD64:
2295 s = ss = US"501 Invalid base64 data";
2296 break;
2297
2298 case CANCELLED:
2299 s = ss = US"501 Authentication cancelled";
2300 break;
2301
2302 case UNEXPECTED:
2303 s = ss = US"553 Initial data not expected";
2304 break;
2305
2306 case FAIL:
2307 s = US"535 Incorrect authentication data";
2308 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2309 break;
2310
2311 default:
2312 s = US"435 Internal error";
2313 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2314 "check", set_id, c);
2315 break;
2316 }
2317
2318 smtp_printf("%s\r\n", s);
2319 if (c != OK)
2320 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2321 au->name, host_and_ident(FALSE), ss);
2322
2323 break; /* AUTH_CMD */
2324
2325 /* The HELO/EHLO commands are permitted to appear in the middle of a
2326 session as well as at the beginning. They have the effect of a reset in
2327 addition to their other functions. Their absence at the start cannot be
2328 taken to be an error.
2329
2330 RFC 2821 says:
2331
2332 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2333 or 502 failure replies MUST be returned as appropriate. The SMTP
2334 server MUST stay in the same state after transmitting these replies
2335 that it was in before the EHLO was received.
2336
2337 Therefore, we do not do the reset until after checking the command for
2338 acceptability. This change was made for Exim release 4.11. Previously
2339 it did the reset first. */
2340
2341 case HELO_CMD:
2342 hello = US"HELO";
2343 esmtp = FALSE;
2344 goto HELO_EHLO;
2345
2346 case EHLO_CMD:
2347 hello = US"EHLO";
2348 esmtp = TRUE;
2349
2350 HELO_EHLO: /* Common code for HELO and EHLO */
2351 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2352 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2353
2354 /* Reject the HELO if its argument was invalid or non-existent. A
2355 successful check causes the argument to be saved in malloc store. */
2356
2357 if (!check_helo(smtp_data))
2358 {
2359 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2360
2361 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2362 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2363 (*smtp_data == 0)? US"(no argument given)" :
2364 string_printing(smtp_data));
2365
2366 if (++synprot_error_count > smtp_max_synprot_errors)
2367 {
2368 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2369 "syntax or protocol errors (last command was \"%s\")",
2370 host_and_ident(FALSE), cmd_buffer);
2371 done = 1;
2372 }
2373
2374 break;
2375 }
2376
2377 /* If sender_host_unknown is true, we have got here via the -bs interface,
2378 not called from inetd. Otherwise, we are running an IP connection and the
2379 host address will be set. If the helo name is the primary name of this
2380 host and we haven't done a reverse lookup, force one now. If helo_required
2381 is set, ensure that the HELO name matches the actual host. If helo_verify
2382 is set, do the same check, but softly. */
2383
2384 if (!sender_host_unknown)
2385 {
2386 BOOL old_helo_verified = helo_verified;
2387 uschar *p = smtp_data;
2388
2389 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2390 *p = 0;
2391
2392 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2393 because otherwise the log can be confusing. */
2394
2395 if (sender_host_name == NULL &&
2396 (deliver_domain = sender_helo_name, /* set $domain */
2397 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2398 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2399 (void)host_name_lookup();
2400
2401 /* Rebuild the fullhost info to include the HELO name (and the real name
2402 if it was looked up.) */
2403
2404 host_build_sender_fullhost(); /* Rebuild */
2405 set_process_info("handling%s incoming connection from %s",
2406 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2407
2408 /* Verify if configured. This doesn't give much security, but it does
2409 make some people happy to be able to do it. If helo_required is set,
2410 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2411 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2412 now obsolescent, since the verification can now be requested selectively
2413 at ACL time. */
2414
2415 helo_verified = helo_verify_failed = FALSE;
2416 if (helo_required || helo_verify)
2417 {
2418 BOOL tempfail = !smtp_verify_helo();
2419 if (!helo_verified)
2420 {
2421 if (helo_required)
2422 {
2423 smtp_printf("%d %s argument does not match calling host\r\n",
2424 tempfail? 451 : 550, hello);
2425 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2426 tempfail? "temporarily " : "",
2427 hello, sender_helo_name, host_and_ident(FALSE));
2428 helo_verified = old_helo_verified;
2429 break; /* End of HELO/EHLO processing */
2430 }
2431 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2432 "helo_try_verify_hosts\n", hello);
2433 }
2434 }
2435 }
2436
2437 #ifdef EXPERIMENTAL_SPF
2438 /* set up SPF context */
2439 spf_init(sender_helo_name, sender_host_address);
2440 #endif
2441
2442 /* Apply an ACL check if one is defined */
2443
2444 if (acl_smtp_helo != NULL)
2445 {
2446 rc = acl_check(ACL_WHERE_HELO, smtp_data, acl_smtp_helo, &user_msg,
2447 &log_msg);
2448 if (rc != OK)
2449 {
2450 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2451 sender_helo_name = NULL;
2452 host_build_sender_fullhost(); /* Rebuild */
2453 break;
2454 }
2455 }
2456
2457 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2458 abandoning any previous message. */
2459
2460 received_protocol = (esmtp?
2461 protocols[pextend +
2462 ((sender_host_authenticated != NULL)? pauthed : 0) +
2463 ((tls_active >= 0)? pcrpted : 0)]
2464 :
2465 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2466 +
2467 ((sender_host_address != NULL)? pnlocal : 0);
2468
2469 smtp_reset(reset_point);
2470 toomany = FALSE;
2471
2472 /* Generate an OK reply, including the ident if present, and also
2473 the IP address if present. Reflecting back the ident is intended
2474 as a deterrent to mail forgers. For maximum efficiency, and also
2475 because some broken systems expect each response to be in a single
2476 packet, arrange that it is sent in one write(). */
2477
2478 auth_advertised = FALSE;
2479 pipelining_advertised = FALSE;
2480 #ifdef SUPPORT_TLS
2481 tls_advertised = FALSE;
2482 #endif
2483
2484 s = string_sprintf("250 %s Hello %s%s%s",
2485 smtp_active_hostname,
2486 (sender_ident == NULL)? US"" : sender_ident,
2487 (sender_ident == NULL)? US"" : US" at ",
2488 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2489
2490 ptr = Ustrlen(s);
2491 size = ptr + 1;
2492
2493 if (sender_host_address != NULL)
2494 {
2495 s = string_cat(s, &size, &ptr, US" [", 2);
2496 s = string_cat(s, &size, &ptr, sender_host_address,
2497 Ustrlen(sender_host_address));
2498 s = string_cat(s, &size, &ptr, US"]", 1);
2499 }
2500
2501 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2502
2503 /* If we received EHLO, we must create a multiline response which includes
2504 the functions supported. */
2505
2506 if (esmtp)
2507 {
2508 s[3] = '-';
2509
2510 /* I'm not entirely happy with this, as an MTA is supposed to check
2511 that it has enough room to accept a message of maximum size before
2512 it sends this. However, there seems little point in not sending it.
2513 The actual size check happens later at MAIL FROM time. By postponing it
2514 till then, VRFY and EXPN can be used after EHLO when space is short. */
2515
2516 if (thismessage_size_limit > 0)
2517 {
2518 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2519 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2520 }
2521 else
2522 {
2523 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2524 }
2525
2526 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2527 clean; if it has an 8-bit character in its hand, it just sends it. It
2528 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2529 However, some users want this option simply in order to stop MUAs
2530 mangling messages that contain top-bit-set characters. It is therefore
2531 provided as an option. */
2532
2533 if (accept_8bitmime)
2534 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2535
2536 /* Advertise ETRN if there's an ACL checking whether a host is
2537 permitted to issue it; a check is made when any host actually tries. */
2538
2539 if (acl_smtp_etrn != NULL)
2540 {
2541 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2542 }
2543
2544 /* Advertise EXPN if there's an ACL checking whether a host is
2545 permitted to issue it; a check is made when any host actually tries. */
2546
2547 if (acl_smtp_expn != NULL)
2548 {
2549 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2550 }
2551
2552 /* Exim is quite happy with pipelining, so let the other end know that
2553 it is safe to use it, unless advertising is disabled. */
2554
2555 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2556 {
2557 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2558 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2559 pipelining_advertised = TRUE;
2560 }
2561
2562 /* If any server authentication mechanisms are configured, advertise
2563 them if the current host is in auth_advertise_hosts. The problem with
2564 advertising always is that some clients then require users to
2565 authenticate (and aren't configurable otherwise) even though it may not
2566 be necessary (e.g. if the host is in host_accept_relay).
2567
2568 RFC 2222 states that SASL mechanism names contain only upper case
2569 letters, so output the names in upper case, though we actually recognize
2570 them in either case in the AUTH command. */
2571
2572 if (auths != NULL)
2573 {
2574 if (verify_check_host(&auth_advertise_hosts) == OK)
2575 {
2576 auth_instance *au;
2577 BOOL first = TRUE;
2578 for (au = auths; au != NULL; au = au->next)
2579 {
2580 if (au->server && (au->advertise_condition == NULL ||
2581 expand_check_condition(au->advertise_condition, au->name,
2582 US"authenticator")))
2583 {
2584 int saveptr;
2585 if (first)
2586 {
2587 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2588 first = FALSE;
2589 auth_advertised = TRUE;
2590 }
2591 saveptr = ptr;
2592 s = string_cat(s, &size, &ptr, US" ", 1);
2593 s = string_cat(s, &size, &ptr, au->public_name,
2594 Ustrlen(au->public_name));
2595 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2596 au->advertised = TRUE;
2597 }
2598 else au->advertised = FALSE;
2599 }
2600 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2601 }
2602 }
2603
2604 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2605 if it has been included in the binary, and the host matches
2606 tls_advertise_hosts. We must *not* advertise if we are already in a
2607 secure connection. */
2608
2609 #ifdef SUPPORT_TLS
2610 if (tls_active < 0 &&
2611 verify_check_host(&tls_advertise_hosts) != FAIL)
2612 {
2613 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2614 tls_advertised = TRUE;
2615 }
2616 #endif
2617
2618 /* Finish off the multiline reply with one that is always available. */
2619
2620 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2621 }
2622
2623 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2624 has been seen. */
2625
2626 s[ptr] = 0;
2627
2628 #ifdef SUPPORT_TLS
2629 if (tls_active >= 0) (void)tls_write(s, ptr); else
2630 #endif
2631
2632 (void)fwrite(s, 1, ptr, smtp_out);
2633 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2634 helo_seen = TRUE;
2635 break; /* HELO/EHLO */
2636
2637
2638 /* The MAIL command requires an address as an operand. All we do
2639 here is to parse it for syntactic correctness. The form "<>" is
2640 a special case which converts into an empty string. The start/end
2641 pointers in the original are not used further for this address, as
2642 it is the canonical extracted address which is all that is kept. */
2643
2644 case MAIL_CMD:
2645 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2646 was_rej_mail = TRUE; /* Reset if accepted */
2647
2648 if (helo_required && !helo_seen)
2649 {
2650 smtp_printf("503 HELO or EHLO required\r\n");
2651 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2652 "HELO/EHLO given", host_and_ident(FALSE));
2653 break;
2654 }
2655
2656 if (sender_address != NULL)
2657 {
2658 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2659 US"sender already given");
2660 break;
2661 }
2662
2663 if (smtp_data[0] == 0)
2664 {
2665 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2666 US"MAIL must have an address operand");
2667 break;
2668 }
2669
2670 /* Check to see if the limit for messages per connection would be
2671 exceeded by accepting further messages. */
2672
2673 if (smtp_accept_max_per_connection > 0 &&
2674 smtp_mailcmd_count > smtp_accept_max_per_connection)
2675 {
2676 smtp_printf("421 too many messages in this connection\r\n");
2677 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2678 "messages in one connection", host_and_ident(TRUE));
2679 break;
2680 }
2681
2682 /* Reset for start of message - even if this is going to fail, we
2683 obviously need to throw away any previous data. */
2684
2685 smtp_reset(reset_point);
2686 toomany = FALSE;
2687 sender_data = recipient_data = NULL;
2688
2689 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2690
2691 if (esmtp) for(;;)
2692 {
2693 uschar *name, *value, *end;
2694 unsigned long int size;
2695
2696 if (!extract_option(&name, &value)) break;
2697
2698 /* Handle SIZE= by reading the value. We don't do the check till later,
2699 in order to be able to log the sender address on failure. */
2700
2701 if (strcmpic(name, US"SIZE") == 0 &&
2702 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2703 {
2704 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2705 size = INT_MAX;
2706 message_size = (int)size;
2707 }
2708
2709 /* If this session was initiated with EHLO and accept_8bitmime is set,
2710 Exim will have indicated that it supports the BODY=8BITMIME option. In
2711 fact, it does not support this according to the RFCs, in that it does not
2712 take any special action for forwarding messages containing 8-bit
2713 characters. That is why accept_8bitmime is not the default setting, but
2714 some sites want the action that is provided. We recognize both "8BITMIME"
2715 and "7BIT" as body types, but take no action. */
2716
2717 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2718 (strcmpic(value, US"8BITMIME") == 0 ||
2719 strcmpic(value, US"7BIT") == 0)) {}
2720
2721 /* Handle the AUTH extension. If the value given is not "<>" and either
2722 the ACL says "yes" or there is no ACL but the sending host is
2723 authenticated, we set it up as the authenticated sender. However, if the
2724 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2725 the condition is met. The value of AUTH is an xtext, which means that +,
2726 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2727 coding. */
2728
2729 else if (strcmpic(name, US"AUTH") == 0)
2730 {
2731 if (Ustrcmp(value, "<>") != 0)
2732 {
2733 int rc;
2734 uschar *ignore_msg;
2735
2736 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2737 {
2738 /* Put back terminator overrides for error message */
2739 name[-1] = ' ';
2740 value[-1] = '=';
2741 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2742 US"invalid data for AUTH");
2743 goto COMMAND_LOOP;
2744 }
2745
2746 if (acl_smtp_mailauth == NULL)
2747 {
2748 ignore_msg = US"client not authenticated";
2749 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2750 }
2751 else
2752 {
2753 ignore_msg = US"rejected by ACL";
2754 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2755 &user_msg, &log_msg);
2756 }
2757
2758 switch (rc)
2759 {
2760 case OK:
2761 if (authenticated_by == NULL ||
2762 authenticated_by->mail_auth_condition == NULL ||
2763 expand_check_condition(authenticated_by->mail_auth_condition,
2764 authenticated_by->name, US"authenticator"))
2765 break; /* Accept the AUTH */
2766
2767 ignore_msg = US"server_mail_auth_condition failed";
2768 if (authenticated_id != NULL)
2769 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2770 ignore_msg, authenticated_id);
2771
2772 /* Fall through */
2773
2774 case FAIL:
2775 authenticated_sender = NULL;
2776 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2777 value, host_and_ident(TRUE), ignore_msg);
2778 break;
2779
2780 /* Should only get DEFER or ERROR here. Put back terminator
2781 overrides for error message */
2782
2783 default:
2784 name[-1] = ' ';
2785 value[-1] = '=';
2786 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2787 log_msg);
2788 goto COMMAND_LOOP;
2789 }
2790 }
2791 }
2792
2793 /* Unknown option. Stick back the terminator characters and break
2794 the loop. An error for a malformed address will occur. */
2795
2796 else
2797 {
2798 name[-1] = ' ';
2799 value[-1] = '=';
2800 break;
2801 }
2802 }
2803
2804 /* If we have passed the threshold for rate limiting, apply the current
2805 delay, and update it for next time, provided this is a limited host. */
2806
2807 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2808 verify_check_host(&smtp_ratelimit_hosts) == OK)
2809 {
2810 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2811 smtp_delay_mail/1000.0);
2812 millisleep((int)smtp_delay_mail);
2813 smtp_delay_mail *= smtp_rlm_factor;
2814 if (smtp_delay_mail > (double)smtp_rlm_limit)
2815 smtp_delay_mail = (double)smtp_rlm_limit;
2816 }
2817
2818 /* Now extract the address, first applying any SMTP-time rewriting. The
2819 TRUE flag allows "<>" as a sender address. */
2820
2821 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2822 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2823 global_rewrite_rules) : smtp_data;
2824
2825 /* rfc821_domains = TRUE; << no longer needed */
2826 raw_sender =
2827 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2828 TRUE);
2829 /* rfc821_domains = FALSE; << no longer needed */
2830
2831 if (raw_sender == NULL)
2832 {
2833 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2834 break;
2835 }
2836
2837 sender_address = raw_sender;
2838
2839 /* If there is a configured size limit for mail, check that this message
2840 doesn't exceed it. The check is postponed to this point so that the sender
2841 can be logged. */
2842
2843 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2844 {
2845 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2846 log_write(L_size_reject,
2847 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2848 "message too big: size%s=%d max=%d",
2849 sender_address,
2850 host_and_ident(TRUE),
2851 (message_size == INT_MAX)? ">" : "",
2852 message_size,
2853 thismessage_size_limit);
2854 sender_address = NULL;
2855 break;
2856 }
2857
2858 /* Check there is enough space on the disk unless configured not to.
2859 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2860 plus the current message - i.e. we accept the message only if it won't
2861 reduce the space below the threshold. Add 5000 to the size to allow for
2862 overheads such as the Received: line and storing of recipients, etc.
2863 By putting the check here, even when SIZE is not given, it allow VRFY
2864 and EXPN etc. to be used when space is short. */
2865
2866 if (!receive_check_fs(
2867 (smtp_check_spool_space && message_size >= 0)?
2868 message_size + 5000 : 0))
2869 {
2870 smtp_printf("452 Space shortage, please try later\r\n");
2871 sender_address = NULL;
2872 break;
2873 }
2874
2875 /* If sender_address is unqualified, reject it, unless this is a locally
2876 generated message, or the sending host or net is permitted to send
2877 unqualified addresses - typically local machines behaving as MUAs -
2878 in which case just qualify the address. The flag is set above at the start
2879 of the SMTP connection. */
2880
2881 if (sender_domain == 0 && sender_address[0] != 0)
2882 {
2883 if (allow_unqualified_sender)
2884 {
2885 sender_domain = Ustrlen(sender_address) + 1;
2886 sender_address = rewrite_address_qualify(sender_address, FALSE);
2887 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2888 raw_sender);
2889 }
2890 else
2891 {
2892 smtp_printf("501 %s: sender address must contain a domain\r\n",
2893 smtp_data);
2894 log_write(L_smtp_syntax_error,
2895 LOG_MAIN|LOG_REJECT,
2896 "unqualified sender rejected: <%s> %s%s",
2897 raw_sender,
2898 host_and_ident(TRUE),
2899 host_lookup_msg);
2900 sender_address = NULL;
2901 break;
2902 }
2903 }
2904
2905 /* Apply an ACL check if one is defined, before responding */
2906
2907 rc = (acl_smtp_mail == NULL)? OK :
2908 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2909
2910 if (rc == OK || rc == DISCARD)
2911 {
2912 smtp_printf("250 OK\r\n");
2913 smtp_delay_rcpt = smtp_rlr_base;
2914 recipients_discarded = (rc == DISCARD);
2915 was_rej_mail = FALSE;
2916 }
2917
2918 else
2919 {
2920 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2921 sender_address = NULL;
2922 }
2923 break;
2924
2925
2926 /* The RCPT command requires an address as an operand. All we do
2927 here is to parse it for syntactic correctness. There may be any number
2928 of RCPT commands, specifying multiple senders. We build them all into
2929 a data structure that is in argc/argv format. The start/end values
2930 given by parse_extract_address are not used, as we keep only the
2931 extracted address. */
2932
2933 case RCPT_CMD:
2934 rcpt_count++;
2935 was_rcpt = TRUE;
2936
2937 /* There must be a sender address; if the sender was rejected and
2938 pipelining was advertised, we assume the client was pipelining, and do not
2939 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2940 get the same treatment. */
2941
2942 if (sender_address == NULL)
2943 {
2944 if (pipelining_advertised && last_was_rej_mail)
2945 {
2946 smtp_printf("503 sender not yet given\r\n");
2947 was_rej_mail = TRUE;
2948 }
2949 else
2950 {
2951 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2952 US"sender not yet given");
2953 was_rcpt = FALSE; /* Not a valid RCPT */
2954 }
2955 rcpt_fail_count++;
2956 break;
2957 }
2958
2959 /* Check for an operand */
2960
2961 if (smtp_data[0] == 0)
2962 {
2963 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2964 US"RCPT must have an address operand");
2965 rcpt_fail_count++;
2966 break;
2967 }
2968
2969 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2970 as a recipient address */
2971
2972 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2973 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2974 global_rewrite_rules) : smtp_data;
2975
2976 /* rfc821_domains = TRUE; << no longer needed */
2977 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2978 &recipient_domain, FALSE);
2979 /* rfc821_domains = FALSE; << no longer needed */
2980
2981 if (recipient == NULL)
2982 {
2983 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2984 rcpt_fail_count++;
2985 break;
2986 }
2987
2988 /* If the recipient address is unqualified, reject it, unless this is a
2989 locally generated message. However, unqualified addresses are permitted
2990 from a configured list of hosts and nets - typically when behaving as
2991 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2992 really. The flag is set at the start of the SMTP connection.
2993
2994 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2995 assumed this meant "reserved local part", but the revision of RFC 821 and
2996 friends now makes it absolutely clear that it means *mailbox*. Consequently
2997 we must always qualify this address, regardless. */
2998
2999 if (recipient_domain == 0)
3000 {
3001 if (allow_unqualified_recipient ||
3002 strcmpic(recipient, US"postmaster") == 0)
3003 {
3004 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3005 recipient);
3006 recipient_domain = Ustrlen(recipient) + 1;
3007 recipient = rewrite_address_qualify(recipient, TRUE);
3008 }
3009 else
3010 {
3011 rcpt_fail_count++;
3012 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3013 smtp_data);
3014 log_write(L_smtp_syntax_error,
3015 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3016 "<%s> %s%s", recipient, host_and_ident(TRUE),
3017 host_lookup_msg);
3018 break;
3019 }
3020 }
3021
3022 /* Check maximum allowed */
3023
3024 if (rcpt_count > recipients_max && recipients_max > 0)
3025 {
3026 if (recipients_max_reject)
3027 {
3028 rcpt_fail_count++;
3029 smtp_printf("552 too many recipients\r\n");
3030 if (!toomany)
3031 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3032 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3033 }
3034 else
3035 {
3036 rcpt_defer_count++;
3037 smtp_printf("452 too many recipients\r\n");
3038 if (!toomany)
3039 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3040 "temporarily rejected: sender=<%s> %s", sender_address,
3041 host_and_ident(TRUE));
3042 }
3043
3044 toomany = TRUE;
3045 break;
3046 }
3047
3048 /* If we have passed the threshold for rate limiting, apply the current
3049 delay, and update it for next time, provided this is a limited host. */
3050
3051 if (rcpt_count > smtp_rlr_threshold &&
3052 verify_check_host(&smtp_ratelimit_hosts) == OK)
3053 {
3054 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3055 smtp_delay_rcpt/1000.0);
3056 millisleep((int)smtp_delay_rcpt);
3057 smtp_delay_rcpt *= smtp_rlr_factor;
3058 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3059 smtp_delay_rcpt = (double)smtp_rlr_limit;
3060 }
3061
3062 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3063 for them. Otherwise, check the access control list for this recipient. */
3064
3065 rc = recipients_discarded? DISCARD :
3066 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3067
3068 /* The ACL was happy */
3069
3070 if (rc == OK)
3071 {
3072 smtp_printf("250 Accepted\r\n");
3073 receive_add_recipient(recipient, -1);
3074 }
3075
3076 /* The recipient was discarded */
3077
3078 else if (rc == DISCARD)
3079 {
3080 smtp_printf("250 Accepted\r\n");
3081 rcpt_fail_count++;
3082 discarded = TRUE;
3083 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3084 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3085 (sender_address_unrewritten != NULL)?
3086 sender_address_unrewritten : sender_address,
3087 smtp_data, recipients_discarded? "MAIL" : "RCPT",
3088 (log_msg == NULL)? US"" : US": ",
3089 (log_msg == NULL)? US"" : log_msg);
3090 }
3091
3092 /* Either the ACL failed the address, or it was deferred. */
3093
3094 else
3095 {
3096 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3097 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3098 }
3099 break;
3100
3101
3102 /* The DATA command is legal only if it follows successful MAIL FROM
3103 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3104 not counted as a protocol error if it follows RCPT (which must have been
3105 rejected if there are no recipients.) This function is complete when a
3106 valid DATA command is encountered.
3107
3108 Note concerning the code used: RFC 2821 says this:
3109
3110 - If there was no MAIL, or no RCPT, command, or all such commands
3111 were rejected, the server MAY return a "command out of sequence"
3112 (503) or "no valid recipients" (554) reply in response to the
3113 DATA command.
3114
3115 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3116 because it is the same whether pipelining is in use or not. */
3117
3118 case DATA_CMD:
3119 if (!discarded && recipients_count <= 0)
3120 {
3121 if (pipelining_advertised && last_was_rcpt)
3122 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3123 else
3124 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3125 US"valid RCPT command must precede DATA");
3126 break;
3127 }
3128
3129 if (toomany && recipients_max_reject)
3130 {
3131 sender_address = NULL; /* This will allow a new MAIL without RSET */
3132 sender_address_unrewritten = NULL;
3133 smtp_printf("554 Too many recipients\r\n");
3134 break;
3135 }
3136
3137 if (acl_smtp_predata == NULL) rc = OK; else
3138 {
3139 enable_dollar_recipients = TRUE;
3140 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3141 &log_msg);
3142 enable_dollar_recipients = FALSE;
3143 }
3144
3145 if (rc == OK)
3146 {
3147 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3148 done = 3;
3149 message_ended = END_NOTENDED; /* Indicate in middle of data */
3150 }
3151
3152 /* Either the ACL failed the address, or it was deferred. */
3153
3154 else
3155 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3156
3157 break;
3158
3159
3160 case VRFY_CMD:
3161 rc = acl_check(ACL_WHERE_VRFY, smtp_data, acl_smtp_vrfy, &user_msg,
3162 &log_msg);
3163 if (rc != OK)
3164 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3165 else
3166 {
3167 uschar *address;
3168 uschar *s = NULL;
3169
3170 /* rfc821_domains = TRUE; << no longer needed */
3171 address = parse_extract_address(smtp_data, &errmess, &start, &end,
3172 &recipient_domain, FALSE);
3173 /* rfc821_domains = FALSE; << no longer needed */
3174
3175 if (address == NULL)
3176 s = string_sprintf("501 %s", errmess);
3177 else
3178 {
3179 address_item *addr = deliver_make_addr(address, FALSE);
3180 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3181 -1, -1, NULL, NULL, NULL))
3182 {
3183 case OK:
3184 s = string_sprintf("250 <%s> is deliverable", address);
3185 break;
3186
3187 case DEFER:
3188 s = (addr->message != NULL)?
3189 string_sprintf("451 <%s> %s", address, addr->message) :
3190 string_sprintf("451 Cannot resolve <%s> at this time", address);
3191 break;
3192
3193 case FAIL:
3194 s = (addr->message != NULL)?
3195 string_sprintf("550 <%s> %s", address, addr->message) :
3196 string_sprintf("550 <%s> is not deliverable", address);
3197 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3198 smtp_data, host_and_ident(TRUE));
3199 break;
3200 }
3201 }
3202
3203 smtp_printf("%s\r\n", s);
3204 }
3205 break;
3206
3207
3208 case EXPN_CMD:
3209 rc = acl_check(ACL_WHERE_EXPN, smtp_data, acl_smtp_expn, &user_msg,
3210 &log_msg);
3211 if (rc != OK)
3212 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3213 else
3214 {
3215 BOOL save_log_testing_mode = log_testing_mode;
3216 address_test_mode = log_testing_mode = TRUE;
3217 (void) verify_address(deliver_make_addr(smtp_data, FALSE), smtp_out,
3218 vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1, NULL, NULL,
3219 NULL);
3220 address_test_mode = FALSE;
3221 log_testing_mode = save_log_testing_mode; /* true for -bh */
3222 }
3223 break;
3224
3225
3226 #ifdef SUPPORT_TLS
3227
3228 case STARTTLS_CMD:
3229 if (!tls_advertised)
3230 {
3231 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3232 US"STARTTLS command used when not advertised");
3233 break;
3234 }
3235
3236 /* Apply an ACL check if one is defined */
3237
3238 if (acl_smtp_starttls != NULL)
3239 {
3240 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3241 &log_msg);
3242 if (rc != OK)
3243 {
3244 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3245 break;
3246 }
3247 }
3248
3249 /* RFC 2487 is not clear on when this command may be sent, though it
3250 does state that all information previously obtained from the client
3251 must be discarded if a TLS session is started. It seems reasonble to
3252 do an implied RSET when STARTTLS is received. */
3253
3254 incomplete_transaction_log(US"STARTTLS");
3255 smtp_reset(reset_point);
3256 toomany = FALSE;
3257 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3258
3259 /* Attempt to start up a TLS session, and if successful, discard all
3260 knowledge that was obtained previously. At least, that's what the RFC says,
3261 and that's what happens by default. However, in order to work round YAEB,
3262 there is an option to remember the esmtp state. Sigh.
3263
3264 We must allow for an extra EHLO command and an extra AUTH command after
3265 STARTTLS that don't add to the nonmail command count. */
3266
3267 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3268 {
3269 if (!tls_remember_esmtp)
3270 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3271 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3272 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3273 if (sender_helo_name != NULL)
3274 {
3275 store_free(sender_helo_name);
3276 sender_helo_name = NULL;
3277 host_build_sender_fullhost(); /* Rebuild */
3278 set_process_info("handling incoming TLS connection from %s",
3279 host_and_ident(FALSE));
3280 }
3281 received_protocol = (esmtp?
3282 protocols[pextend + pcrpted +
3283 ((sender_host_authenticated != NULL)? pauthed : 0)]
3284 :
3285 protocols[pnormal + pcrpted])
3286 +
3287 ((sender_host_address != NULL)? pnlocal : 0);
3288
3289 sender_host_authenticated = NULL;
3290 authenticated_id = NULL;
3291 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3292 DEBUG(D_tls) debug_printf("TLS active\n");
3293 break; /* Successful STARTTLS */
3294 }
3295
3296 /* Some local configuration problem was discovered before actually trying
3297 to do a TLS handshake; give a temporary error. */
3298
3299 else if (rc == DEFER)
3300 {
3301 smtp_printf("454 TLS currently unavailable\r\n");
3302 break;
3303 }
3304
3305 /* Hard failure. Reject everything except QUIT or closed connection. One
3306 cause for failure is a nested STARTTLS, in which case tls_active remains
3307 set, but we must still reject all incoming commands. */
3308
3309 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3310 while (done <= 0)
3311 {
3312 switch(smtp_read_command(FALSE))
3313 {
3314 case EOF_CMD:
3315 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3316 smtp_get_connection_info());
3317 done = 2;
3318 break;
3319
3320 case QUIT_CMD:
3321 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3322 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3323 smtp_get_connection_info());
3324 done = 2;
3325 break;
3326
3327 default:
3328 smtp_printf("554 Security failure\r\n");
3329 break;
3330 }
3331 }
3332 tls_close(TRUE);
3333 break;
3334 #endif
3335
3336
3337 /* The ACL for QUIT is provided for gathering statistical information or
3338 similar; it does not affect the response code, but it can supply a custom
3339 message. */
3340
3341 case QUIT_CMD:
3342 incomplete_transaction_log(US"QUIT");
3343
3344 if (acl_smtp_quit != NULL)
3345 {
3346 rc = acl_check(ACL_WHERE_QUIT, US"", acl_smtp_quit,&user_msg,&log_msg);
3347 if (rc == ERROR)
3348 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3349 log_msg);
3350 }
3351 else user_msg = NULL;
3352
3353 if (user_msg == NULL)
3354 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3355 else
3356 smtp_printf("221 %s\r\n", user_msg);
3357
3358 #ifdef SUPPORT_TLS
3359 tls_close(TRUE);
3360 #endif
3361
3362 done = 2;
3363 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3364 smtp_get_connection_info());
3365 break;
3366
3367
3368 case RSET_CMD:
3369 incomplete_transaction_log(US"RSET");
3370 smtp_reset(reset_point);
3371 toomany = FALSE;
3372 smtp_printf("250 Reset OK\r\n");
3373 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3374 break;
3375
3376
3377 case NOOP_CMD:
3378 smtp_printf("250 OK\r\n");
3379 break;
3380
3381
3382 /* Show ETRN/EXPN/VRFY if there's
3383 an ACL for checking hosts; if actually used, a check will be done for
3384 permitted hosts. */
3385
3386 case HELP_CMD:
3387 smtp_printf("214-Commands supported:\r\n");
3388 {
3389 uschar buffer[256];
3390 buffer[0] = 0;
3391 Ustrcat(buffer, " AUTH");
3392 #ifdef SUPPORT_TLS
3393 Ustrcat(buffer, " STARTTLS");
3394 #endif
3395 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3396 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3397 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3398 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3399 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3400 smtp_printf("214%s\r\n", buffer);
3401 }
3402 break;
3403
3404
3405 case EOF_CMD:
3406 incomplete_transaction_log(US"connection lost");
3407 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3408
3409 /* Don't log by default unless in the middle of a message, as some mailers
3410 just drop the call rather than sending QUIT, and it clutters up the logs.
3411 */
3412
3413 if (sender_address != NULL || recipients_count > 0)
3414 log_write(L_lost_incoming_connection,
3415 LOG_MAIN,
3416 "unexpected %s while reading SMTP command from %s%s",
3417 sender_host_unknown? "EOF" : "disconnection",
3418 host_and_ident(FALSE), smtp_read_error);
3419
3420 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3421 smtp_get_connection_info(), smtp_read_error);
3422
3423 done = 1;
3424 break;
3425
3426
3427 case ETRN_CMD:
3428 if (sender_address != NULL)
3429 {
3430 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3431 US"ETRN is not permitted inside a transaction");
3432 break;
3433 }
3434
3435 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_data,
3436 host_and_ident(FALSE));
3437
3438 rc = acl_check(ACL_WHERE_ETRN, smtp_data, acl_smtp_etrn, &user_msg,
3439 &log_msg);
3440 if (rc != OK)
3441 {
3442 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3443 break;
3444 }
3445
3446 /* Compute the serialization key for this command. */
3447
3448 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_data);
3449
3450 /* If a command has been specified for running as a result of ETRN, we
3451 permit any argument to ETRN. If not, only the # standard form is permitted,
3452 since that is strictly the only kind of ETRN that can be implemented
3453 according to the RFC. */
3454
3455 if (smtp_etrn_command != NULL)
3456 {
3457 uschar *error;
3458 BOOL rc;
3459 etrn_command = smtp_etrn_command;
3460 deliver_domain = smtp_data;
3461 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3462 US"ETRN processing", &error);
3463 deliver_domain = NULL;
3464 if (!rc)
3465 {
3466 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3467 error);
3468 smtp_printf("458 Internal failure\r\n");
3469 break;
3470 }
3471 }
3472
3473 /* Else set up to call Exim with the -R option. */
3474
3475 else
3476 {
3477 if (*smtp_data++ != '#')
3478 {
3479 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3480 US"argument must begin with #");
3481 break;
3482 }
3483 etrn_command = US"exim -R";
3484 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3485 smtp_data);
3486 }
3487
3488 /* If we are host-testing, don't actually do anything. */
3489
3490 if (host_checking)
3491 {
3492 HDEBUG(D_any)
3493 {
3494 debug_printf("ETRN command is: %s\n", etrn_command);
3495 debug_printf("ETRN command execution skipped\n");
3496 }
3497 smtp_printf("250 OK\r\n");
3498 break;
3499 }
3500
3501
3502 /* If ETRN queue runs are to be serialized, check the database to
3503 ensure one isn't already running. */
3504
3505 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3506 {
3507 smtp_printf("458 Already processing %s\r\n", smtp_data);
3508 break;
3509 }
3510
3511 /* Fork a child process and run the command. We don't want to have to
3512 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3513 forking. It should be set that way anyway for external incoming SMTP,
3514 but we save and restore to be tidy. If serialization is required, we