Make $smtp_command_argument available for all SMTP commands.
[exim.git] / src / src / smtp_in.c
1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.23 2005/08/22 14:01:37 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 *cmd_buffer;
123
124 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
125 final fields of all except AUTH are forced TRUE at the start of a new message
126 setup, to allow one of each between messages that is not counted as a nonmail
127 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
128 allow a new EHLO after starting up TLS.
129
130 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
131 counted. However, the flag is changed when AUTH is received, so that multiple
132 failing AUTHs will eventually hit the limit. After a successful AUTH, another
133 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
134 forced TRUE, to allow for the re-authentication that can happen at that point.
135
136 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
137 count of non-mail commands and possibly provoke an error. */
138
139 static smtp_cmd_list cmd_list[] = {
140 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
141 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
142 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
143 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
144 #ifdef SUPPORT_TLS
145 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
146 #endif
147
148 /* If you change anything above here, also fix the definitions below. */
149
150 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
151 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
152 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
153 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
154 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
155 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
156 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
157 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
158 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
159 };
160
161 static smtp_cmd_list *cmd_list_end =
162 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
163
164 #define CMD_LIST_RSET 0
165 #define CMD_LIST_HELO 1
166 #define CMD_LIST_EHLO 2
167 #define CMD_LIST_AUTH 3
168 #define CMD_LIST_STARTTLS 4
169
170 static uschar *protocols[] = {
171 US"local-smtp", /* HELO */
172 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
173 US"local-esmtp", /* EHLO */
174 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
175 US"local-esmtpa", /* EHLO->AUTH */
176 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
177 };
178
179 #define pnormal 0
180 #define pextend 2
181 #define pcrpted 1 /* added to pextend or pnormal */
182 #define pauthed 2 /* added to pextend */
183 #define pnlocal 6 /* offset to remove "local" */
184
185 /* When reading SMTP from a remote host, we have to use our own versions of the
186 C input-reading functions, in order to be able to flush the SMTP output only
187 when about to read more data from the socket. This is the only way to get
188 optimal performance when the client is using pipelining. Flushing for every
189 command causes a separate packet and reply packet each time; saving all the
190 responses up (when pipelining) combines them into one packet and one response.
191
192 For simplicity, these functions are used for *all* SMTP input, not only when
193 receiving over a socket. However, after setting up a secure socket (SSL), input
194 is read via the OpenSSL library, and another set of functions is used instead
195 (see tls.c).
196
197 These functions are set in the receive_getc etc. variables and called with the
198 same interface as the C functions. However, since there can only ever be
199 one incoming SMTP call, we just use a single buffer and flags. There is no need
200 to implement a complicated private FILE-like structure.*/
201
202 static uschar *smtp_inbuffer;
203 static uschar *smtp_inptr;
204 static uschar *smtp_inend;
205 static int smtp_had_eof;
206 static int smtp_had_error;
207
208
209 /*************************************************
210 * SMTP version of getc() *
211 *************************************************/
212
213 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
214 it flushes the output, and refills the buffer, with a timeout. The signal
215 handler is set appropriately by the calling function. This function is not used
216 after a connection has negotated itself into an TLS/SSL state.
217
218 Arguments: none
219 Returns: the next character or EOF
220 */
221
222 int
223 smtp_getc(void)
224 {
225 if (smtp_inptr >= smtp_inend)
226 {
227 int rc, save_errno;
228 fflush(smtp_out);
229 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
230 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
231 save_errno = errno;
232 alarm(0);
233 if (rc <= 0)
234 {
235 /* Must put the error text in fixed store, because this might be during
236 header reading, where it releases unused store above the header. */
237 if (rc < 0)
238 {
239 smtp_had_error = save_errno;
240 smtp_read_error = string_copy_malloc(
241 string_sprintf(" (error: %s)", strerror(save_errno)));
242 }
243 else smtp_had_eof = 1;
244 return EOF;
245 }
246 smtp_inend = smtp_inbuffer + rc;
247 smtp_inptr = smtp_inbuffer;
248 }
249 return *smtp_inptr++;
250 }
251
252
253
254 /*************************************************
255 * SMTP version of ungetc() *
256 *************************************************/
257
258 /* Puts a character back in the input buffer. Only ever
259 called once.
260
261 Arguments:
262 ch the character
263
264 Returns: the character
265 */
266
267 int
268 smtp_ungetc(int ch)
269 {
270 *(--smtp_inptr) = ch;
271 return ch;
272 }
273
274
275
276
277 /*************************************************
278 * SMTP version of feof() *
279 *************************************************/
280
281 /* Tests for a previous EOF
282
283 Arguments: none
284 Returns: non-zero if the eof flag is set
285 */
286
287 int
288 smtp_feof(void)
289 {
290 return smtp_had_eof;
291 }
292
293
294
295
296 /*************************************************
297 * SMTP version of ferror() *
298 *************************************************/
299
300 /* Tests for a previous read error, and returns with errno
301 restored to what it was when the error was detected.
302
303 Arguments: none
304 Returns: non-zero if the error flag is set
305 */
306
307 int
308 smtp_ferror(void)
309 {
310 errno = smtp_had_error;
311 return smtp_had_error;
312 }
313
314
315
316
317 /*************************************************
318 * Write formatted string to SMTP channel *
319 *************************************************/
320
321 /* This is a separate function so that we don't have to repeat everything for
322 TLS support or debugging. It is global so that the daemon and the
323 authentication functions can use it. It does not return any error indication,
324 because major problems such as dropped connections won't show up till an output
325 flush for non-TLS connections. The smtp_fflush() function is available for
326 checking that: for convenience, TLS output errors are remembered here so that
327 they are also picked up later by smtp_fflush().
328
329 Arguments:
330 format format string
331 ... optional arguments
332
333 Returns: nothing
334 */
335
336 void
337 smtp_printf(char *format, ...)
338 {
339 va_list ap;
340
341 DEBUG(D_receive)
342 {
343 va_start(ap, format);
344 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
345 debug_printf("SMTP>> %s", big_buffer);
346 }
347
348 va_start(ap, format);
349
350 /* If in a TLS session we have to format the string, and then write it using a
351 TLS function. */
352
353 #ifdef SUPPORT_TLS
354 if (tls_active >= 0)
355 {
356 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
357 {
358 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
359 smtp_closedown(US"Unexpected error");
360 exim_exit(EXIT_FAILURE);
361 }
362 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
363 }
364 else
365 #endif
366
367 /* Otherwise, just use the standard library function. */
368
369 if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
370 va_end(ap);
371 }
372
373
374
375 /*************************************************
376 * Flush SMTP out and check for error *
377 *************************************************/
378
379 /* This function isn't currently used within Exim (it detects errors when it
380 tries to read the next SMTP input), but is available for use in local_scan().
381 For non-TLS connections, it flushes the output and checks for errors. For
382 TLS-connections, it checks for a previously-detected TLS write error.
383
384 Arguments: none
385 Returns: 0 for no error; -1 after an error
386 */
387
388 int
389 smtp_fflush(void)
390 {
391 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
392 return smtp_write_error;
393 }
394
395
396
397 /*************************************************
398 * SMTP command read timeout *
399 *************************************************/
400
401 /* Signal handler for timing out incoming SMTP commands. This attempts to
402 finish off tidily.
403
404 Argument: signal number (SIGALRM)
405 Returns: nothing
406 */
407
408 static void
409 command_timeout_handler(int sig)
410 {
411 sig = sig; /* Keep picky compilers happy */
412 log_write(L_lost_incoming_connection,
413 LOG_MAIN, "SMTP command timeout on%s connection from %s",
414 (tls_active >= 0)? " TLS" : "",
415 host_and_ident(FALSE));
416 if (smtp_batched_input)
417 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
418 smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
419 smtp_active_hostname);
420 mac_smtp_fflush();
421 exim_exit(EXIT_FAILURE);
422 }
423
424
425
426 /*************************************************
427 * SIGTERM received *
428 *************************************************/
429
430 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
431
432 Argument: signal number (SIGTERM)
433 Returns: nothing
434 */
435
436 static void
437 command_sigterm_handler(int sig)
438 {
439 sig = sig; /* Keep picky compilers happy */
440 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
441 if (smtp_batched_input)
442 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
443 smtp_printf("421 %s: Service not available - closing connection\r\n",
444 smtp_active_hostname);
445 exim_exit(EXIT_FAILURE);
446 }
447
448
449
450 /*************************************************
451 * Read one command line *
452 *************************************************/
453
454 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
455 There are sites that don't do this, and in any case internal SMTP probably
456 should check only for LF. Consequently, we check here for LF only. The line
457 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
458 an unknown command. The command is read into the static cmd_buffer.
459
460 The character reading routine sets up a timeout for each block actually read
461 from the input (which may contain more than one command). We set up a special
462 signal handler that closes down the session on a timeout. Control does not
463 return when it runs.
464
465 Arguments:
466 check_sync if TRUE, check synchronization rules if global option is TRUE
467
468 Returns: a code identifying the command (enumerated above)
469 */
470
471 static int
472 smtp_read_command(BOOL check_sync)
473 {
474 int c;
475 int ptr = 0;
476 smtp_cmd_list *p;
477 BOOL hadnull = FALSE;
478
479 os_non_restarting_signal(SIGALRM, command_timeout_handler);
480
481 while ((c = (receive_getc)()) != '\n' && c != EOF)
482 {
483 if (ptr >= cmd_buffer_size)
484 {
485 os_non_restarting_signal(SIGALRM, sigalrm_handler);
486 return OTHER_CMD;
487 }
488 if (c == 0)
489 {
490 hadnull = TRUE;
491 c = '?';
492 }
493 cmd_buffer[ptr++] = c;
494 }
495
496 receive_linecount++; /* For BSMTP errors */
497 os_non_restarting_signal(SIGALRM, sigalrm_handler);
498
499 /* If hit end of file, return pseudo EOF command. Whether we have a
500 part-line already read doesn't matter, since this is an error state. */
501
502 if (c == EOF) return EOF_CMD;
503
504 /* Remove any CR and white space at the end of the line, and terminate the
505 string. */
506
507 while (ptr > 0 && isspace(cmd_buffer[ptr-1])) ptr--;
508 cmd_buffer[ptr] = 0;
509
510 DEBUG(D_receive) debug_printf("SMTP<< %s\n", cmd_buffer);
511
512 /* NULLs are not allowed in SMTP commands */
513
514 if (hadnull) return BADCHAR_CMD;
515
516 /* Scan command list and return identity, having set the data pointer
517 to the start of the actual data characters. Check for SMTP synchronization
518 if required. */
519
520 for (p = cmd_list; p < cmd_list_end; p++)
521 {
522 if (strncmpic(cmd_buffer, US p->name, p->len) == 0)
523 {
524 if (smtp_inptr < smtp_inend && /* Outstanding input */
525 p->cmd < sync_cmd_limit && /* Command should sync */
526 check_sync && /* Local flag set */
527 smtp_enforce_sync && /* Global flag set */
528 sender_host_address != NULL && /* Not local input */
529 !sender_host_notsocket) /* Really is a socket */
530 return BADSYN_CMD;
531
532 /* Point after the command, but don't skip over leading spaces till after
533 the following test, so that if it fails, the command name can easily be
534 logged. */
535
536 smtp_command_argument = cmd_buffer + p->len;
537
538 /* Count non-mail commands from those hosts that are controlled in this
539 way. The default is all hosts. We don't waste effort checking the list
540 until we get a non-mail command, but then cache the result to save checking
541 again. If there's a DEFER while checking the host, assume it's in the list.
542
543 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
544 start of each incoming message by fiddling with the value in the table. */
545
546 if (!p->is_mail_cmd)
547 {
548 if (count_nonmail == TRUE_UNSET) count_nonmail =
549 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
550 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
551 return TOO_MANY_NONMAIL_CMD;
552 }
553
554 /* Get the data pointer over leading spaces and return; if there is data
555 for a command that does not expect it, give the error centrally here. */
556
557 while (isspace(*smtp_command_argument)) smtp_command_argument++;
558 return (p->has_arg || *smtp_command_argument == 0)? p->cmd : BADARG_CMD;
559 }
560 }
561
562 /* Enforce synchronization for unknown commands */
563
564 if (smtp_inptr < smtp_inend && /* Outstanding input */
565 check_sync && /* Local flag set */
566 smtp_enforce_sync && /* Global flag set */
567 sender_host_address != NULL && /* Not local input */
568 !sender_host_notsocket) /* Really is a socket */
569 return BADSYN_CMD;
570
571 return OTHER_CMD;
572 }
573
574
575
576 /*************************************************
577 * Forced closedown of call *
578 *************************************************/
579
580 /* This function is called from log.c when Exim is dying because of a serious
581 disaster, and also from some other places. If an incoming non-batched SMTP
582 channel is open, it swallows the rest of the incoming message if in the DATA
583 phase, sends the reply string, and gives an error to all subsequent commands
584 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
585 smtp_in.
586
587 Argument: SMTP reply string to send, excluding the code
588 Returns: nothing
589 */
590
591 void
592 smtp_closedown(uschar *message)
593 {
594 if (smtp_in == NULL || smtp_batched_input) return;
595 receive_swallow_smtp();
596 smtp_printf("421 %s\r\n", message);
597
598 for (;;)
599 {
600 switch(smtp_read_command(FALSE))
601 {
602 case EOF_CMD:
603 return;
604
605 case QUIT_CMD:
606 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
607 mac_smtp_fflush();
608 return;
609
610 case RSET_CMD:
611 smtp_printf("250 Reset OK\r\n");
612 break;
613
614 default:
615 smtp_printf("421 %s\r\n", message);
616 break;
617 }
618 }
619 }
620
621
622
623
624 /*************************************************
625 * Set up connection info for logging *
626 *************************************************/
627
628 /* This function is called when logging information about an SMTP connection.
629 It sets up appropriate source information, depending on the type of connection.
630
631 Argument: none
632 Returns: a string describing the connection
633 */
634
635 uschar *
636 smtp_get_connection_info(void)
637 {
638 if (host_checking)
639 return string_sprintf("SMTP connection from %s", sender_fullhost);
640
641 if (sender_host_unknown || sender_host_notsocket)
642 return string_sprintf("SMTP connection from %s", sender_ident);
643
644 if (is_inetd)
645 return string_sprintf("SMTP connection from %s (via inetd)", sender_fullhost);
646
647 if ((log_extra_selector & LX_incoming_interface) != 0 &&
648 interface_address != NULL)
649 return string_sprintf("SMTP connection from %s I=[%s]:%d", sender_fullhost,
650 interface_address, interface_port);
651
652 return string_sprintf("SMTP connection from %s", sender_fullhost);
653 }
654
655
656
657 /*************************************************
658 * Check HELO line and set sender_helo_name *
659 *************************************************/
660
661 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
662 the domain name of the sending host, or an ip literal in square brackets. The
663 arrgument is placed in sender_helo_name, which is in malloc store, because it
664 must persist over multiple incoming messages. If helo_accept_junk is set, this
665 host is permitted to send any old junk (needed for some broken hosts).
666 Otherwise, helo_allow_chars can be used for rogue characters in general
667 (typically people want to let in underscores).
668
669 Argument:
670 s the data portion of the line (already past any white space)
671
672 Returns: TRUE or FALSE
673 */
674
675 static BOOL
676 check_helo(uschar *s)
677 {
678 uschar *start = s;
679 uschar *end = s + Ustrlen(s);
680 BOOL yield = helo_accept_junk;
681
682 /* Discard any previous helo name */
683
684 if (sender_helo_name != NULL)
685 {
686 store_free(sender_helo_name);
687 sender_helo_name = NULL;
688 }
689
690 /* Skip tests if junk is permitted. */
691
692 if (!yield)
693 {
694 /* Allow the new standard form for IPv6 address literals, namely,
695 [IPv6:....], and because someone is bound to use it, allow an equivalent
696 IPv4 form. Allow plain addresses as well. */
697
698 if (*s == '[')
699 {
700 if (end[-1] == ']')
701 {
702 end[-1] = 0;
703 if (strncmpic(s, US"[IPv6:", 6) == 0)
704 yield = (string_is_ip_address(s+6, NULL) == 6);
705 else if (strncmpic(s, US"[IPv4:", 6) == 0)
706 yield = (string_is_ip_address(s+6, NULL) == 4);
707 else
708 yield = (string_is_ip_address(s+1, NULL) != 0);
709 end[-1] = ']';
710 }
711 }
712
713 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
714 that have been configured (usually underscore - sigh). */
715
716 else if (*s != 0)
717 {
718 yield = TRUE;
719 while (*s != 0)
720 {
721 if (!isalnum(*s) && *s != '.' && *s != '-' &&
722 Ustrchr(helo_allow_chars, *s) == NULL)
723 {
724 yield = FALSE;
725 break;
726 }
727 s++;
728 }
729 }
730 }
731
732 /* Save argument if OK */
733
734 if (yield) sender_helo_name = string_copy_malloc(start);
735 return yield;
736 }
737
738
739
740
741
742 /*************************************************
743 * Extract SMTP command option *
744 *************************************************/
745
746 /* This function picks the next option setting off the end of smtp_command_argument. It
747 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
748 things that can appear there.
749
750 Arguments:
751 name point this at the name
752 value point this at the data string
753
754 Returns: TRUE if found an option
755 */
756
757 static BOOL
758 extract_option(uschar **name, uschar **value)
759 {
760 uschar *n;
761 uschar *v = smtp_command_argument + Ustrlen(smtp_command_argument) -1;
762 while (isspace(*v)) v--;
763 v[1] = 0;
764
765 while (v > smtp_command_argument && *v != '=' && !isspace(*v)) v--;
766 if (*v != '=') return FALSE;
767
768 n = v;
769 while(isalpha(n[-1])) n--;
770
771 if (n[-1] != ' ') return FALSE;
772
773 n[-1] = 0;
774 *name = n;
775 *v++ = 0;
776 *value = v;
777 return TRUE;
778 }
779
780
781
782
783
784
785
786 /*************************************************
787 * Reset for new message *
788 *************************************************/
789
790 /* This function is called whenever the SMTP session is reset from
791 within either of the setup functions.
792
793 Argument: the stacking pool storage reset point
794 Returns: nothing
795 */
796
797 static void
798 smtp_reset(void *reset_point)
799 {
800 int i;
801 store_reset(reset_point);
802 recipients_list = NULL;
803 rcpt_count = rcpt_defer_count = rcpt_fail_count =
804 raw_recipients_count = recipients_count = recipients_list_max = 0;
805 message_linecount = 0;
806 message_size = -1;
807 acl_warn_headers = NULL;
808 queue_only_policy = FALSE;
809 deliver_freeze = FALSE; /* Can be set by ACL */
810 fake_response = OK; /* Can be set by ACL */
811 #ifdef WITH_CONTENT_SCAN
812 no_mbox_unspool = FALSE; /* Can be set by ACL */
813 #endif
814 submission_mode = FALSE; /* Can be set by ACL */
815 active_local_from_check = local_from_check; /* Can be set by ACL */
816 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
817 sender_address = NULL;
818 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
819 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
820 sender_verified_list = NULL; /* No senders verified */
821 memset(sender_address_cache, 0, sizeof(sender_address_cache));
822 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
823 authenticated_sender = NULL;
824 #ifdef EXPERIMENTAL_BRIGHTMAIL
825 bmi_run = 0;
826 bmi_verdicts = NULL;
827 #endif
828 #ifdef EXPERIMENTAL_DOMAINKEYS
829 dk_do_verify = 0;
830 #endif
831 #ifdef EXPERIMENTAL_SPF
832 spf_header_comment = NULL;
833 spf_received = NULL;
834 spf_result = NULL;
835 spf_smtp_comment = NULL;
836 #endif
837 body_linecount = body_zerocount = 0;
838
839 sender_rate = sender_rate_limit = sender_rate_period = NULL;
840 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
841 /* Note that ratelimiters_conn persists across resets. */
842
843 for (i = 0; i < ACL_M_MAX; i++) acl_var[ACL_C_MAX + i] = NULL;
844
845 /* The message body variables use malloc store. They may be set if this is
846 not the first message in an SMTP session and the previous message caused them
847 to be referenced in an ACL. */
848
849 if (message_body != NULL)
850 {
851 store_free(message_body);
852 message_body = NULL;
853 }
854
855 if (message_body_end != NULL)
856 {
857 store_free(message_body_end);
858 message_body_end = NULL;
859 }
860
861 /* Warning log messages are also saved in malloc store. They are saved to avoid
862 repetition in the same message, but it seems right to repeat them for different
863 messagess. */
864
865 while (acl_warn_logged != NULL)
866 {
867 string_item *this = acl_warn_logged;
868 acl_warn_logged = acl_warn_logged->next;
869 store_free(this);
870 }
871 }
872
873
874
875
876
877 /*************************************************
878 * Initialize for incoming batched SMTP message *
879 *************************************************/
880
881 /* This function is called from smtp_setup_msg() in the case when
882 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
883 of messages in one file with SMTP commands between them. All errors must be
884 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
885 relevant. After an error on a sender, or an invalid recipient, the remainder
886 of the message is skipped. The value of received_protocol is already set.
887
888 Argument: none
889 Returns: > 0 message successfully started (reached DATA)
890 = 0 QUIT read or end of file reached
891 < 0 should not occur
892 */
893
894 static int
895 smtp_setup_batch_msg(void)
896 {
897 int done = 0;
898 void *reset_point = store_get(0);
899
900 /* Save the line count at the start of each transaction - single commands
901 like HELO and RSET count as whole transactions. */
902
903 bsmtp_transaction_linecount = receive_linecount;
904
905 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
906
907 smtp_reset(reset_point); /* Reset for start of message */
908
909 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
910 value. The values are 2 larger than the required yield of the function. */
911
912 while (done <= 0)
913 {
914 uschar *errmess;
915 uschar *recipient = NULL;
916 int start, end, sender_domain, recipient_domain;
917
918 switch(smtp_read_command(FALSE))
919 {
920 /* The HELO/EHLO commands set sender_address_helo if they have
921 valid data; otherwise they are ignored, except that they do
922 a reset of the state. */
923
924 case HELO_CMD:
925 case EHLO_CMD:
926
927 check_helo(smtp_command_argument);
928 /* Fall through */
929
930 case RSET_CMD:
931 smtp_reset(reset_point);
932 bsmtp_transaction_linecount = receive_linecount;
933 break;
934
935
936 /* The MAIL FROM command requires an address as an operand. All we
937 do here is to parse it for syntactic correctness. The form "<>" is
938 a special case which converts into an empty string. The start/end
939 pointers in the original are not used further for this address, as
940 it is the canonical extracted address which is all that is kept. */
941
942 case MAIL_CMD:
943 if (sender_address != NULL)
944 /* The function moan_smtp_batch() does not return. */
945 moan_smtp_batch(cmd_buffer, "503 Sender already given");
946
947 if (smtp_command_argument[0] == 0)
948 /* The function moan_smtp_batch() does not return. */
949 moan_smtp_batch(cmd_buffer, "501 MAIL FROM must have an address operand");
950
951 /* Reset to start of message */
952
953 smtp_reset(reset_point);
954
955 /* Apply SMTP rewrite */
956
957 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
958 rewrite_one(smtp_command_argument, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
959 US"", global_rewrite_rules) : smtp_command_argument;
960
961 /* Extract the address; the TRUE flag allows <> as valid */
962
963 raw_sender =
964 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
965 TRUE);
966
967 if (raw_sender == NULL)
968 /* The function moan_smtp_batch() does not return. */
969 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
970
971 sender_address = string_copy(raw_sender);
972
973 /* Qualify unqualified sender addresses if permitted to do so. */
974
975 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
976 {
977 if (allow_unqualified_sender)
978 {
979 sender_address = rewrite_address_qualify(sender_address, FALSE);
980 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
981 "and rewritten\n", raw_sender);
982 }
983 /* The function moan_smtp_batch() does not return. */
984 else moan_smtp_batch(cmd_buffer, "501 sender address must contain "
985 "a domain");
986 }
987 break;
988
989
990 /* The RCPT TO command requires an address as an operand. All we do
991 here is to parse it for syntactic correctness. There may be any number
992 of RCPT TO commands, specifying multiple senders. We build them all into
993 a data structure that is in argc/argv format. The start/end values
994 given by parse_extract_address are not used, as we keep only the
995 extracted address. */
996
997 case RCPT_CMD:
998 if (sender_address == NULL)
999 /* The function moan_smtp_batch() does not return. */
1000 moan_smtp_batch(cmd_buffer, "503 No sender yet given");
1001
1002 if (smtp_command_argument[0] == 0)
1003 /* The function moan_smtp_batch() does not return. */
1004 moan_smtp_batch(cmd_buffer, "501 RCPT TO must have an address operand");
1005
1006 /* Check maximum number allowed */
1007
1008 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1009 /* The function moan_smtp_batch() does not return. */
1010 moan_smtp_batch(cmd_buffer, "%s too many recipients",
1011 recipients_max_reject? "552": "452");
1012
1013 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1014 recipient address */
1015
1016 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1017 rewrite_one(smtp_command_argument, rewrite_smtp, NULL, FALSE, US"",
1018 global_rewrite_rules) : smtp_command_argument;
1019
1020 /* rfc821_domains = TRUE; << no longer needed */
1021 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1022 &recipient_domain, FALSE);
1023 /* rfc821_domains = FALSE; << no longer needed */
1024
1025 if (recipient == NULL)
1026 /* The function moan_smtp_batch() does not return. */
1027 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
1028
1029 /* If the recipient address is unqualified, qualify it if permitted. Then
1030 add it to the list of recipients. */
1031
1032 if (recipient_domain == 0)
1033 {
1034 if (allow_unqualified_recipient)
1035 {
1036 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1037 recipient);
1038 recipient = rewrite_address_qualify(recipient, TRUE);
1039 }
1040 /* The function moan_smtp_batch() does not return. */
1041 else moan_smtp_batch(cmd_buffer, "501 recipient address must contain "
1042 "a domain");
1043 }
1044 receive_add_recipient(recipient, -1);
1045 break;
1046
1047
1048 /* The DATA command is legal only if it follows successful MAIL FROM
1049 and RCPT TO commands. This function is complete when a valid DATA
1050 command is encountered. */
1051
1052 case DATA_CMD:
1053 if (sender_address == NULL || recipients_count <= 0)
1054 {
1055 /* The function moan_smtp_batch() does not return. */
1056 if (sender_address == NULL)
1057 moan_smtp_batch(cmd_buffer,
1058 "503 MAIL FROM:<sender> command must precede DATA");
1059 else
1060 moan_smtp_batch(cmd_buffer,
1061 "503 RCPT TO:<recipient> must precede DATA");
1062 }
1063 else
1064 {
1065 done = 3; /* DATA successfully achieved */
1066 message_ended = END_NOTENDED; /* Indicate in middle of message */
1067 }
1068 break;
1069
1070
1071 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1072
1073 case VRFY_CMD:
1074 case EXPN_CMD:
1075 case HELP_CMD:
1076 case NOOP_CMD:
1077 case ETRN_CMD:
1078 bsmtp_transaction_linecount = receive_linecount;
1079 break;
1080
1081
1082 case EOF_CMD:
1083 case QUIT_CMD:
1084 done = 2;
1085 break;
1086
1087
1088 case BADARG_CMD:
1089 /* The function moan_smtp_batch() does not return. */
1090 moan_smtp_batch(cmd_buffer, "501 Unexpected argument data");
1091 break;
1092
1093
1094 case BADCHAR_CMD:
1095 /* The function moan_smtp_batch() does not return. */
1096 moan_smtp_batch(cmd_buffer, "501 Unexpected NULL in SMTP command");
1097 break;
1098
1099
1100 default:
1101 /* The function moan_smtp_batch() does not return. */
1102 moan_smtp_batch(cmd_buffer, "500 Command unrecognized");
1103 break;
1104 }
1105 }
1106
1107 return done - 2; /* Convert yield values */
1108 }
1109
1110
1111
1112
1113 /*************************************************
1114 * Start an SMTP session *
1115 *************************************************/
1116
1117 /* This function is called at the start of an SMTP session. Thereafter,
1118 smtp_setup_msg() is called to initiate each separate message. This
1119 function does host-specific testing, and outputs the banner line.
1120
1121 Arguments: none
1122 Returns: FALSE if the session can not continue; something has
1123 gone wrong, or the connection to the host is blocked
1124 */
1125
1126 BOOL
1127 smtp_start_session(void)
1128 {
1129 int size = 256;
1130 int i, ptr;
1131 uschar *p, *s, *ss;
1132
1133 /* If we are running in the test harness, and the incoming call is from
1134 127.0.0.2 (sic), have a short delay. This makes it possible to test handling of
1135 input sent too soon (before the banner is output). */
1136
1137 if (running_in_test_harness &&
1138 sender_host_address != NULL &&
1139 Ustrcmp(sender_host_address, "127.0.0.2") == 0)
1140 sleep(1);
1141
1142 /* Default values for certain variables */
1143
1144 helo_seen = esmtp = helo_accept_junk = FALSE;
1145 count_nonmail = TRUE_UNSET;
1146 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1147 smtp_delay_mail = smtp_rlm_base;
1148 auth_advertised = FALSE;
1149 pipelining_advertised = FALSE;
1150 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1151
1152 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1153
1154 sender_host_authenticated = NULL;
1155 authenticated_by = NULL;
1156
1157 #ifdef SUPPORT_TLS
1158 tls_cipher = tls_peerdn = NULL;
1159 tls_advertised = FALSE;
1160 #endif
1161
1162 /* Reset ACL connection variables */
1163
1164 for (i = 0; i < ACL_C_MAX; i++) acl_var[i] = NULL;
1165
1166 cmd_buffer = (uschar *)malloc(cmd_buffer_size + 1); /* allow for trailing 0 */
1167 if (cmd_buffer == NULL)
1168 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1169 "malloc() failed for SMTP command buffer");
1170
1171 /* For batched input, the protocol setting can be overridden from the
1172 command line by a trusted caller. */
1173
1174 if (smtp_batched_input)
1175 {
1176 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1177 }
1178
1179 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1180 reset later if any of EHLO/AUTH/STARTTLS are received. */
1181
1182 else
1183 received_protocol =
1184 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1185
1186 /* Set up the buffer for inputting using direct read() calls, and arrange to
1187 call the local functions instead of the standard C ones. */
1188
1189 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1190 if (smtp_inbuffer == NULL)
1191 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1192 receive_getc = smtp_getc;
1193 receive_ungetc = smtp_ungetc;
1194 receive_feof = smtp_feof;
1195 receive_ferror = smtp_ferror;
1196 smtp_inptr = smtp_inend = smtp_inbuffer;
1197 smtp_had_eof = smtp_had_error = 0;
1198
1199 /* Set up the message size limit; this may be host-specific */
1200
1201 thismessage_size_limit = expand_string_integer(message_size_limit);
1202 if (thismessage_size_limit < 0)
1203 {
1204 if (thismessage_size_limit == -1)
1205 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1206 "%s", expand_string_message);
1207 else
1208 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1209 "%s", expand_string_message);
1210 smtp_closedown(US"Temporary local problem - please try later");
1211 return FALSE;
1212 }
1213
1214 /* When a message is input locally via the -bs or -bS options, sender_host_
1215 unknown is set unless -oMa was used to force an IP address, in which case it
1216 is checked like a real remote connection. When -bs is used from inetd, this
1217 flag is not set, causing the sending host to be checked. The code that deals
1218 with IP source routing (if configured) is never required for -bs or -bS and
1219 the flag sender_host_notsocket is used to suppress it.
1220
1221 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1222 reserve for certain hosts and/or networks. */
1223
1224 if (!sender_host_unknown)
1225 {
1226 int rc;
1227 BOOL reserved_host = FALSE;
1228
1229 /* Look up IP options (source routing info) on the socket if this is not an
1230 -oMa "host", and if any are found, log them and drop the connection.
1231
1232 Linux (and others now, see below) is different to everyone else, so there
1233 has to be some conditional compilation here. Versions of Linux before 2.1.15
1234 used a structure whose name was "options". Somebody finally realized that
1235 this name was silly, and it got changed to "ip_options". I use the
1236 newer name here, but there is a fudge in the script that sets up os.h
1237 to define a macro in older Linux systems.
1238
1239 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1240 glibc 2, which has chosen ip_opts for the structure name. This is now
1241 really a glibc thing rather than a Linux thing, so the condition name
1242 has been changed to reflect this. It is relevant also to GNU/Hurd.
1243
1244 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1245 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1246 a special macro defined in the os.h file.
1247
1248 Some DGUX versions on older hardware appear not to support IP options at
1249 all, so there is now a general macro which can be set to cut out this
1250 support altogether.
1251
1252 How to do this properly in IPv6 is not yet known. */
1253
1254 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1255
1256 #ifdef GLIBC_IP_OPTIONS
1257 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1258 #define OPTSTYLE 1
1259 #else
1260 #define OPTSTYLE 2
1261 #endif
1262 #elif defined DARWIN_IP_OPTIONS
1263 #define OPTSTYLE 2
1264 #else
1265 #define OPTSTYLE 3
1266 #endif
1267
1268 if (!host_checking && !sender_host_notsocket)
1269 {
1270 #if OPTSTYLE == 1
1271 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1272 struct ip_options *ipopt = store_get(optlen);
1273 #elif OPTSTYLE == 2
1274 struct ip_opts ipoptblock;
1275 struct ip_opts *ipopt = &ipoptblock;
1276 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1277 #else
1278 struct ipoption ipoptblock;
1279 struct ipoption *ipopt = &ipoptblock;
1280 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1281 #endif
1282
1283 /* Occasional genuine failures of getsockopt() have been seen - for
1284 example, "reset by peer". Therefore, just log and give up on this
1285 call, unless the error is ENOPROTOOPT. This error is given by systems
1286 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1287 of writing. So for that error, carry on - we just can't do an IP options
1288 check. */
1289
1290 DEBUG(D_receive) debug_printf("checking for IP options\n");
1291
1292 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1293 &optlen) < 0)
1294 {
1295 if (errno != ENOPROTOOPT)
1296 {
1297 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1298 host_and_ident(FALSE), strerror(errno));
1299 smtp_printf("451 SMTP service not available\r\n");
1300 return FALSE;
1301 }
1302 }
1303
1304 /* Deal with any IP options that are set. On the systems I have looked at,
1305 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1306 more logging data than will fit in big_buffer. Nevertheless, after somebody
1307 questioned this code, I've added in some paranoid checking. */
1308
1309 else if (optlen > 0)
1310 {
1311 uschar *p = big_buffer;
1312 uschar *pend = big_buffer + big_buffer_size;
1313 uschar *opt, *adptr;
1314 int optcount;
1315 struct in_addr addr;
1316
1317 #if OPTSTYLE == 1
1318 uschar *optstart = (uschar *)(ipopt->__data);
1319 #elif OPTSTYLE == 2
1320 uschar *optstart = (uschar *)(ipopt->ip_opts);
1321 #else
1322 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1323 #endif
1324
1325 DEBUG(D_receive) debug_printf("IP options exist\n");
1326
1327 Ustrcpy(p, "IP options on incoming call:");
1328 p += Ustrlen(p);
1329
1330 for (opt = optstart; opt != NULL &&
1331 opt < (uschar *)(ipopt) + optlen;)
1332 {
1333 switch (*opt)
1334 {
1335 case IPOPT_EOL:
1336 opt = NULL;
1337 break;
1338
1339 case IPOPT_NOP:
1340 opt++;
1341 break;
1342
1343 case IPOPT_SSRR:
1344 case IPOPT_LSRR:
1345 if (!string_format(p, pend-p, " %s [@%s",
1346 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1347 #if OPTSTYLE == 1
1348 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1349 #elif OPTSTYLE == 2
1350 inet_ntoa(ipopt->ip_dst)))
1351 #else
1352 inet_ntoa(ipopt->ipopt_dst)))
1353 #endif
1354 {
1355 opt = NULL;
1356 break;
1357 }
1358
1359 p += Ustrlen(p);
1360 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1361 adptr = opt + 3;
1362 while (optcount-- > 0)
1363 {
1364 memcpy(&addr, adptr, sizeof(addr));
1365 if (!string_format(p, pend - p - 1, "%s%s",
1366 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1367 {
1368 opt = NULL;
1369 break;
1370 }
1371 p += Ustrlen(p);
1372 adptr += sizeof(struct in_addr);
1373 }
1374 *p++ = ']';
1375 opt += opt[1];
1376 break;
1377
1378 default:
1379 {
1380 int i;
1381 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1382 Ustrcat(p, "[ ");
1383 p += 2;
1384 for (i = 0; i < opt[1]; i++)
1385 {
1386 sprintf(CS p, "%2.2x ", opt[i]);
1387 p += 3;
1388 }
1389 *p++ = ']';
1390 }
1391 opt += opt[1];
1392 break;
1393 }
1394 }
1395
1396 *p = 0;
1397 log_write(0, LOG_MAIN, "%s", big_buffer);
1398
1399 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1400
1401 log_write(0, LOG_MAIN|LOG_REJECT,
1402 "connection from %s refused (IP options)", host_and_ident(FALSE));
1403
1404 smtp_printf("554 SMTP service not available\r\n");
1405 return FALSE;
1406 }
1407
1408 /* Length of options = 0 => there are no options */
1409
1410 else DEBUG(D_receive) debug_printf("no IP options found\n");
1411 }
1412 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1413
1414 /* Set keep-alive in socket options. The option is on by default. This
1415 setting is an attempt to get rid of some hanging connections that stick in
1416 read() when the remote end (usually a dialup) goes away. */
1417
1418 if (smtp_accept_keepalive && !sender_host_notsocket)
1419 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1420
1421 /* If the current host matches host_lookup, set the name by doing a
1422 reverse lookup. On failure, sender_host_name will be NULL and
1423 host_lookup_failed will be TRUE. This may or may not be serious - optional
1424 checks later. */
1425
1426 if (verify_check_host(&host_lookup) == OK)
1427 {
1428 (void)host_name_lookup();
1429 host_build_sender_fullhost();
1430 }
1431
1432 /* Delay this until we have the full name, if it is looked up. */
1433
1434 set_process_info("handling incoming connection from %s",
1435 host_and_ident(FALSE));
1436
1437 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1438 smtps port for use with older style SSL MTAs. */
1439
1440 #ifdef SUPPORT_TLS
1441 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1442 return FALSE;
1443 #endif
1444
1445 /* Test for explicit connection rejection */
1446
1447 if (verify_check_host(&host_reject_connection) == OK)
1448 {
1449 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1450 "from %s (host_reject_connection)", host_and_ident(FALSE));
1451 smtp_printf("554 SMTP service not available\r\n");
1452 return FALSE;
1453 }
1454
1455 /* Test with TCP Wrappers if so configured */
1456
1457 #ifdef USE_TCP_WRAPPERS
1458 if (!hosts_ctl("exim",
1459 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1460 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1461 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1462 {
1463 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1464 log_write(L_connection_reject,
1465 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1466 "(tcp wrappers)", host_and_ident(FALSE));
1467 smtp_printf("554 SMTP service not available\r\n");
1468 return FALSE;
1469 }
1470 #endif
1471
1472 /* Check for reserved slots. Note that the count value doesn't include
1473 this process, as it gets upped in the parent process. */
1474
1475 if (smtp_accept_max > 0 &&
1476 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1477 {
1478 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1479 {
1480 log_write(L_connection_reject,
1481 LOG_MAIN, "temporarily refused connection from %s: not in "
1482 "reserve list: connected=%d max=%d reserve=%d%s",
1483 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1484 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1485 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1486 "please try again later\r\n", smtp_active_hostname);
1487 return FALSE;
1488 }
1489 reserved_host = TRUE;
1490 }
1491
1492 /* If a load level above which only messages from reserved hosts are
1493 accepted is set, check the load. For incoming calls via the daemon, the
1494 check is done in the superior process if there are no reserved hosts, to
1495 save a fork. In all cases, the load average will already be available
1496 in a global variable at this point. */
1497
1498 if (smtp_load_reserve >= 0 &&
1499 load_average > smtp_load_reserve &&
1500 !reserved_host &&
1501 verify_check_host(&smtp_reserve_hosts) != OK)
1502 {
1503 log_write(L_connection_reject,
1504 LOG_MAIN, "temporarily refused connection from %s: not in "
1505 "reserve list and load average = %.2f", host_and_ident(FALSE),
1506 (double)load_average/1000.0);
1507 smtp_printf("421 %s: Too much load; please try again later\r\n",
1508 smtp_active_hostname);
1509 return FALSE;
1510 }
1511
1512 /* Determine whether unqualified senders or recipients are permitted
1513 for this host. Unfortunately, we have to do this every time, in order to
1514 set the flags so that they can be inspected when considering qualifying
1515 addresses in the headers. For a site that permits no qualification, this
1516 won't take long, however. */
1517
1518 allow_unqualified_sender =
1519 verify_check_host(&sender_unqualified_hosts) == OK;
1520
1521 allow_unqualified_recipient =
1522 verify_check_host(&recipient_unqualified_hosts) == OK;
1523
1524 /* Determine whether HELO/EHLO is required for this host. The requirement
1525 can be hard or soft. */
1526
1527 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1528 if (!helo_required)
1529 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1530
1531 /* Determine whether this hosts is permitted to send syntactic junk
1532 after a HELO or EHLO command. */
1533
1534 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1535 }
1536
1537 /* For batch SMTP input we are now done. */
1538
1539 if (smtp_batched_input) return TRUE;
1540
1541 /* Run the ACL if it exists */
1542
1543 if (acl_smtp_connect != NULL)
1544 {
1545 int rc;
1546 uschar *user_msg, *log_msg;
1547 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1548 &log_msg);
1549 if (rc != OK)
1550 {
1551 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1552 return FALSE;
1553 }
1554 }
1555
1556 /* Output the initial message for a two-way SMTP connection. It may contain
1557 newlines, which then cause a multi-line response to be given. */
1558
1559 s = expand_string(smtp_banner);
1560 if (s == NULL)
1561 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1562 "failed: %s", smtp_banner, expand_string_message);
1563
1564 /* Remove any terminating newlines; might as well remove trailing space too */
1565
1566 p = s + Ustrlen(s);
1567 while (p > s && isspace(p[-1])) p--;
1568 *p = 0;
1569
1570 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1571 is all contained in a single IP packet. The original code wrote out the
1572 greeting using several calls to fprint/fputc, and on busy servers this could
1573 cause it to be split over more than one packet - which caused CC:Mail to fall
1574 over when it got the second part of the greeting after sending its first
1575 command. Sigh. To try to avoid this, build the complete greeting message
1576 first, and output it in one fell swoop. This gives a better chance of it
1577 ending up as a single packet. */
1578
1579 ss = store_get(size);
1580 ptr = 0;
1581
1582 p = s;
1583 do /* At least once, in case we have an empty string */
1584 {
1585 int len;
1586 uschar *linebreak = Ustrchr(p, '\n');
1587 if (linebreak == NULL)
1588 {
1589 len = Ustrlen(p);
1590 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1591 }
1592 else
1593 {
1594 len = linebreak - p;
1595 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1596 }
1597 ss = string_cat(ss, &size, &ptr, p, len);
1598 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1599 p += len;
1600 if (linebreak != NULL) p++;
1601 }
1602 while (*p != 0);
1603
1604 ss[ptr] = 0; /* string_cat leaves room for this */
1605
1606 /* Before we write the banner, check that there is no input pending, unless
1607 this synchronisation check is disabled. */
1608
1609 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1610 {
1611 fd_set fds;
1612 struct timeval tzero;
1613 tzero.tv_sec = 0;
1614 tzero.tv_usec = 0;
1615 FD_ZERO(&fds);
1616 FD_SET(fileno(smtp_in), &fds);
1617 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1618 &tzero) > 0)
1619 {
1620 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1621 if (rc > 0)
1622 {
1623 if (rc > 150) rc = 150;
1624 smtp_inbuffer[rc] = 0;
1625 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1626 "synchronization error (input sent without waiting for greeting): "
1627 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1628 string_printing(smtp_inbuffer));
1629 smtp_printf("554 SMTP synchronization error\r\n");
1630 return FALSE;
1631 }
1632 }
1633 }
1634
1635 /* Now output the banner */
1636
1637 smtp_printf("%s", ss);
1638 return TRUE;
1639 }
1640
1641
1642
1643
1644
1645 /*************************************************
1646 * Handle SMTP syntax and protocol errors *
1647 *************************************************/
1648
1649 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1650 to do so. Then transmit the error response. The return value depends on the
1651 number of syntax and protocol errors in this SMTP session.
1652
1653 Arguments:
1654 type error type, given as a log flag bit
1655 code response code; <= 0 means don't send a response
1656 data data to reflect in the response (can be NULL)
1657 errmess the error message
1658
1659 Returns: -1 limit of syntax/protocol errors NOT exceeded
1660 +1 limit of syntax/protocol errors IS exceeded
1661
1662 These values fit in with the values of the "done" variable in the main
1663 processing loop in smtp_setup_msg(). */
1664
1665 static int
1666 synprot_error(int type, int code, uschar *data, uschar *errmess)
1667 {
1668 int yield = -1;
1669
1670 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1671 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1672 string_printing(cmd_buffer), host_and_ident(TRUE), errmess);
1673
1674 if (++synprot_error_count > smtp_max_synprot_errors)
1675 {
1676 yield = 1;
1677 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1678 "syntax or protocol errors (last command was \"%s\")",
1679 host_and_ident(FALSE), cmd_buffer);
1680 }
1681
1682 if (code > 0)
1683 {
1684 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1685 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1686 if (yield == 1)
1687 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1688 }
1689
1690 return yield;
1691 }
1692
1693
1694
1695
1696 /*************************************************
1697 * Log incomplete transactions *
1698 *************************************************/
1699
1700 /* This function is called after a transaction has been aborted by RSET, QUIT,
1701 connection drops or other errors. It logs the envelope information received
1702 so far in order to preserve address verification attempts.
1703
1704 Argument: string to indicate what aborted the transaction
1705 Returns: nothing
1706 */
1707
1708 static void
1709 incomplete_transaction_log(uschar *what)
1710 {
1711 if (sender_address == NULL || /* No transaction in progress */
1712 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1713 ) return;
1714
1715 /* Build list of recipients for logging */
1716
1717 if (recipients_count > 0)
1718 {
1719 int i;
1720 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1721 for (i = 0; i < recipients_count; i++)
1722 raw_recipients[i] = recipients_list[i].address;
1723 raw_recipients_count = recipients_count;
1724 }
1725
1726 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1727 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1728 }
1729
1730
1731
1732
1733 /*************************************************
1734 * Send SMTP response, possibly multiline *
1735 *************************************************/
1736
1737 /* There are, it seems, broken clients out there that cannot handle multiline
1738 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1739 output nothing for non-final calls, and only the first line for anything else.
1740
1741 Arguments:
1742 code SMTP code
1743 final FALSE if the last line isn't the final line
1744 msg message text, possibly containing newlines
1745
1746 Returns: nothing
1747 */
1748
1749 void
1750 smtp_respond(int code, BOOL final, uschar *msg)
1751 {
1752 if (!final && no_multiline_responses) return;
1753
1754 for (;;)
1755 {
1756 uschar *nl = Ustrchr(msg, '\n');
1757 if (nl == NULL)
1758 {
1759 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1760 return;
1761 }
1762 else if (nl[1] == 0 || no_multiline_responses)
1763 {
1764 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1765 return;
1766 }
1767 else
1768 {
1769 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1770 msg = nl + 1;
1771 while (isspace(*msg)) msg++;
1772 }
1773 }
1774 }
1775
1776
1777
1778
1779 /*************************************************
1780 * Handle an ACL failure *
1781 *************************************************/
1782
1783 /* This function is called when acl_check() fails. As well as calls from within
1784 this module, it is called from receive.c for an ACL after DATA. It sorts out
1785 logging the incident, and sets up the error response. A message containing
1786 newlines is turned into a multiline SMTP response, but for logging, only the
1787 first line is used.
1788
1789 There's a table of the response codes to use in globals.c, along with the table
1790 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1791 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1792 that the response should be 252 in the disabled state, because there are broken
1793 clients that try VRFY before RCPT. A 5xx response should be given only when the
1794 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1795 given on refusal, and for AUTH, 503.
1796
1797 Arguments:
1798 where where the ACL was called from
1799 rc the failure code
1800 user_msg a message that can be included in an SMTP response
1801 log_msg a message for logging
1802
1803 Returns: 0 in most cases
1804 2 if the failure code was FAIL_DROP, in which case the
1805 SMTP connection should be dropped (this value fits with the
1806 "done" variable in smtp_setup_msg() below)
1807 */
1808
1809 int
1810 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1811 {
1812 int code = acl_wherecodes[where];
1813 BOOL drop = rc == FAIL_DROP;
1814 uschar *lognl;
1815 uschar *sender_info = US"";
1816 uschar *what =
1817 #ifdef WITH_CONTENT_SCAN
1818 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1819 #endif
1820 (where == ACL_WHERE_PREDATA)? US"DATA" :
1821 (where == ACL_WHERE_DATA)? US"after DATA" :
1822 (smtp_command_argument == NULL)?
1823 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
1824 string_sprintf("%s %s", acl_wherenames[where], smtp_command_argument);
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, NULL, acl_smtp_auth, &user_msg, &log_msg);
2183 if (rc != OK)
2184 {
2185 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2186 break;
2187 }
2188 }
2189
2190 /* Find the name of the requested authentication mechanism. */
2191
2192 s = smtp_command_argument;
2193 while ((c = *smtp_command_argument) != 0 && !isspace(c))
2194 {
2195 if (!isalnum(c) && c != '-' && c != '_')
2196 {
2197 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2198 US"invalid character in authentication mechanism name");
2199 goto COMMAND_LOOP;
2200 }
2201 smtp_command_argument++;
2202 }
2203
2204 /* If not at the end of the line, we must be at white space. Terminate the
2205 name and move the pointer on to any data that may be present. */
2206
2207 if (*smtp_command_argument != 0)
2208 {
2209 *smtp_command_argument++ = 0;
2210 while (isspace(*smtp_command_argument)) smtp_command_argument++;
2211 }
2212
2213 /* Search for an authentication mechanism which is configured for use
2214 as a server and which has been advertised. */
2215
2216 for (au = auths; au != NULL; au = au->next)
2217 {
2218 if (strcmpic(s, au->public_name) == 0 && au->server &&
2219 au->advertised) break;
2220 }
2221
2222 if (au == NULL)
2223 {
2224 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2225 string_sprintf("%s authentication mechanism not supported", s));
2226 break;
2227 }
2228
2229 /* Run the checking code, passing the remainder of the command
2230 line as data. Initialize $0 empty. The authenticator may set up
2231 other numeric variables. Afterwards, have a go at expanding the set_id
2232 string, even if authentication failed - for bad passwords it can be useful
2233 to log the userid. On success, require set_id to expand and exist, and
2234 put it in authenticated_id. Save this in permanent store, as the working
2235 store gets reset at HELO, RSET, etc. */
2236
2237 expand_nmax = 0;
2238 expand_nlength[0] = 0; /* $0 contains nothing */
2239
2240 c = (au->info->servercode)(au, smtp_command_argument);
2241 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2242 expand_nmax = -1; /* Reset numeric variables */
2243
2244 /* The value of authenticated_id is stored in the spool file and printed in
2245 log lines. It must not contain binary zeros or newline characters. In
2246 normal use, it never will, but when playing around or testing, this error
2247 can (did) happen. To guard against this, ensure that the id contains only
2248 printing characters. */
2249
2250 if (set_id != NULL) set_id = string_printing(set_id);
2251
2252 /* For the non-OK cases, set up additional logging data if set_id
2253 is not empty. */
2254
2255 if (c != OK)
2256 {
2257 if (set_id != NULL && *set_id != 0)
2258 set_id = string_sprintf(" (set_id=%s)", set_id);
2259 else set_id = US"";
2260 }
2261
2262 /* Switch on the result */
2263
2264 switch(c)
2265 {
2266 case OK:
2267 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2268 {
2269 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2270 sender_host_authenticated = au->name;
2271 authentication_failed = FALSE;
2272 received_protocol =
2273 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2274 ((sender_host_address != NULL)? pnlocal : 0);
2275 s = ss = US"235 Authentication succeeded";
2276 authenticated_by = au;
2277 break;
2278 }
2279
2280 /* Authentication succeeded, but we failed to expand the set_id string.
2281 Treat this as a temporary error. */
2282
2283 auth_defer_msg = expand_string_message;
2284 /* Fall through */
2285
2286 case DEFER:
2287 s = string_sprintf("435 Unable to authenticate at present%s",
2288 auth_defer_user_msg);
2289 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2290 set_id, auth_defer_msg);
2291 break;
2292
2293 case BAD64:
2294 s = ss = US"501 Invalid base64 data";
2295 break;
2296
2297 case CANCELLED:
2298 s = ss = US"501 Authentication cancelled";
2299 break;
2300
2301 case UNEXPECTED:
2302 s = ss = US"553 Initial data not expected";
2303 break;
2304
2305 case FAIL:
2306 s = US"535 Incorrect authentication data";
2307 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2308 break;
2309
2310 default:
2311 s = US"435 Internal error";
2312 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2313 "check", set_id, c);
2314 break;
2315 }
2316
2317 smtp_printf("%s\r\n", s);
2318 if (c != OK)
2319 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2320 au->name, host_and_ident(FALSE), ss);
2321
2322 break; /* AUTH_CMD */
2323
2324 /* The HELO/EHLO commands are permitted to appear in the middle of a
2325 session as well as at the beginning. They have the effect of a reset in
2326 addition to their other functions. Their absence at the start cannot be
2327 taken to be an error.
2328
2329 RFC 2821 says:
2330
2331 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2332 or 502 failure replies MUST be returned as appropriate. The SMTP
2333 server MUST stay in the same state after transmitting these replies
2334 that it was in before the EHLO was received.
2335
2336 Therefore, we do not do the reset until after checking the command for
2337 acceptability. This change was made for Exim release 4.11. Previously
2338 it did the reset first. */
2339
2340 case HELO_CMD:
2341 hello = US"HELO";
2342 esmtp = FALSE;
2343 goto HELO_EHLO;
2344
2345 case EHLO_CMD:
2346 hello = US"EHLO";
2347 esmtp = TRUE;
2348
2349 HELO_EHLO: /* Common code for HELO and EHLO */
2350 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2351 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2352
2353 /* Reject the HELO if its argument was invalid or non-existent. A
2354 successful check causes the argument to be saved in malloc store. */
2355
2356 if (!check_helo(smtp_command_argument))
2357 {
2358 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2359
2360 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2361 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2362 (*smtp_command_argument == 0)? US"(no argument given)" :
2363 string_printing(smtp_command_argument));
2364
2365 if (++synprot_error_count > smtp_max_synprot_errors)
2366 {
2367 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2368 "syntax or protocol errors (last command was \"%s\")",
2369 host_and_ident(FALSE), cmd_buffer);
2370 done = 1;
2371 }
2372
2373 break;
2374 }
2375
2376 /* If sender_host_unknown is true, we have got here via the -bs interface,
2377 not called from inetd. Otherwise, we are running an IP connection and the
2378 host address will be set. If the helo name is the primary name of this
2379 host and we haven't done a reverse lookup, force one now. If helo_required
2380 is set, ensure that the HELO name matches the actual host. If helo_verify
2381 is set, do the same check, but softly. */
2382
2383 if (!sender_host_unknown)
2384 {
2385 BOOL old_helo_verified = helo_verified;
2386 uschar *p = smtp_command_argument;
2387
2388 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2389 *p = 0;
2390
2391 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2392 because otherwise the log can be confusing. */
2393
2394 if (sender_host_name == NULL &&
2395 (deliver_domain = sender_helo_name, /* set $domain */
2396 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2397 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2398 (void)host_name_lookup();
2399
2400 /* Rebuild the fullhost info to include the HELO name (and the real name
2401 if it was looked up.) */
2402
2403 host_build_sender_fullhost(); /* Rebuild */
2404 set_process_info("handling%s incoming connection from %s",
2405 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2406
2407 /* Verify if configured. This doesn't give much security, but it does
2408 make some people happy to be able to do it. If helo_required is set,
2409 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2410 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2411 now obsolescent, since the verification can now be requested selectively
2412 at ACL time. */
2413
2414 helo_verified = helo_verify_failed = FALSE;
2415 if (helo_required || helo_verify)
2416 {
2417 BOOL tempfail = !smtp_verify_helo();
2418 if (!helo_verified)
2419 {
2420 if (helo_required)
2421 {
2422 smtp_printf("%d %s argument does not match calling host\r\n",
2423 tempfail? 451 : 550, hello);
2424 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2425 tempfail? "temporarily " : "",
2426 hello, sender_helo_name, host_and_ident(FALSE));
2427 helo_verified = old_helo_verified;
2428 break; /* End of HELO/EHLO processing */
2429 }
2430 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2431 "helo_try_verify_hosts\n", hello);
2432 }
2433 }
2434 }
2435
2436 #ifdef EXPERIMENTAL_SPF
2437 /* set up SPF context */
2438 spf_init(sender_helo_name, sender_host_address);
2439 #endif
2440
2441 /* Apply an ACL check if one is defined */
2442
2443 if (acl_smtp_helo != NULL)
2444 {
2445 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2446 if (rc != OK)
2447 {
2448 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2449 sender_helo_name = NULL;
2450 host_build_sender_fullhost(); /* Rebuild */
2451 break;
2452 }
2453 }
2454
2455 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2456 abandoning any previous message. */
2457
2458 received_protocol = (esmtp?
2459 protocols[pextend +
2460 ((sender_host_authenticated != NULL)? pauthed : 0) +
2461 ((tls_active >= 0)? pcrpted : 0)]
2462 :
2463 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2464 +
2465 ((sender_host_address != NULL)? pnlocal : 0);
2466
2467 smtp_reset(reset_point);
2468 toomany = FALSE;
2469
2470 /* Generate an OK reply, including the ident if present, and also
2471 the IP address if present. Reflecting back the ident is intended
2472 as a deterrent to mail forgers. For maximum efficiency, and also
2473 because some broken systems expect each response to be in a single
2474 packet, arrange that it is sent in one write(). */
2475
2476 auth_advertised = FALSE;
2477 pipelining_advertised = FALSE;
2478 #ifdef SUPPORT_TLS
2479 tls_advertised = FALSE;
2480 #endif
2481
2482 s = string_sprintf("250 %s Hello %s%s%s",
2483 smtp_active_hostname,
2484 (sender_ident == NULL)? US"" : sender_ident,
2485 (sender_ident == NULL)? US"" : US" at ",
2486 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2487
2488 ptr = Ustrlen(s);
2489 size = ptr + 1;
2490
2491 if (sender_host_address != NULL)
2492 {
2493 s = string_cat(s, &size, &ptr, US" [", 2);
2494 s = string_cat(s, &size, &ptr, sender_host_address,
2495 Ustrlen(sender_host_address));
2496 s = string_cat(s, &size, &ptr, US"]", 1);
2497 }
2498
2499 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2500
2501 /* If we received EHLO, we must create a multiline response which includes
2502 the functions supported. */
2503
2504 if (esmtp)
2505 {
2506 s[3] = '-';
2507
2508 /* I'm not entirely happy with this, as an MTA is supposed to check
2509 that it has enough room to accept a message of maximum size before
2510 it sends this. However, there seems little point in not sending it.
2511 The actual size check happens later at MAIL FROM time. By postponing it
2512 till then, VRFY and EXPN can be used after EHLO when space is short. */
2513
2514 if (thismessage_size_limit > 0)
2515 {
2516 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2517 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2518 }
2519 else
2520 {
2521 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2522 }
2523
2524 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2525 clean; if it has an 8-bit character in its hand, it just sends it. It
2526 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2527 However, some users want this option simply in order to stop MUAs
2528 mangling messages that contain top-bit-set characters. It is therefore
2529 provided as an option. */
2530
2531 if (accept_8bitmime)
2532 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2533
2534 /* Advertise ETRN if there's an ACL checking whether a host is
2535 permitted to issue it; a check is made when any host actually tries. */
2536
2537 if (acl_smtp_etrn != NULL)
2538 {
2539 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2540 }
2541
2542 /* Advertise EXPN if there's an ACL checking whether a host is
2543 permitted to issue it; a check is made when any host actually tries. */
2544
2545 if (acl_smtp_expn != NULL)
2546 {
2547 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2548 }
2549
2550 /* Exim is quite happy with pipelining, so let the other end know that
2551 it is safe to use it, unless advertising is disabled. */
2552
2553 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2554 {
2555 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2556 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2557 pipelining_advertised = TRUE;
2558 }
2559
2560 /* If any server authentication mechanisms are configured, advertise
2561 them if the current host is in auth_advertise_hosts. The problem with
2562 advertising always is that some clients then require users to
2563 authenticate (and aren't configurable otherwise) even though it may not
2564 be necessary (e.g. if the host is in host_accept_relay).
2565
2566 RFC 2222 states that SASL mechanism names contain only upper case
2567 letters, so output the names in upper case, though we actually recognize
2568 them in either case in the AUTH command. */
2569
2570 if (auths != NULL)
2571 {
2572 if (verify_check_host(&auth_advertise_hosts) == OK)
2573 {
2574 auth_instance *au;
2575 BOOL first = TRUE;
2576 for (au = auths; au != NULL; au = au->next)
2577 {
2578 if (au->server && (au->advertise_condition == NULL ||
2579 expand_check_condition(au->advertise_condition, au->name,
2580 US"authenticator")))
2581 {
2582 int saveptr;
2583 if (first)
2584 {
2585 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2586 first = FALSE;
2587 auth_advertised = TRUE;
2588 }
2589 saveptr = ptr;
2590 s = string_cat(s, &size, &ptr, US" ", 1);
2591 s = string_cat(s, &size, &ptr, au->public_name,
2592 Ustrlen(au->public_name));
2593 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2594 au->advertised = TRUE;
2595 }
2596 else au->advertised = FALSE;
2597 }
2598 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2599 }
2600 }
2601
2602 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2603 if it has been included in the binary, and the host matches
2604 tls_advertise_hosts. We must *not* advertise if we are already in a
2605 secure connection. */
2606
2607 #ifdef SUPPORT_TLS
2608 if (tls_active < 0 &&
2609 verify_check_host(&tls_advertise_hosts) != FAIL)
2610 {
2611 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2612 tls_advertised = TRUE;
2613 }
2614 #endif
2615
2616 /* Finish off the multiline reply with one that is always available. */
2617
2618 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2619 }
2620
2621 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2622 has been seen. */
2623
2624 s[ptr] = 0;
2625
2626 #ifdef SUPPORT_TLS
2627 if (tls_active >= 0) (void)tls_write(s, ptr); else
2628 #endif
2629
2630 (void)fwrite(s, 1, ptr, smtp_out);
2631 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2632 helo_seen = TRUE;
2633 break; /* HELO/EHLO */
2634
2635
2636 /* The MAIL command requires an address as an operand. All we do
2637 here is to parse it for syntactic correctness. The form "<>" is
2638 a special case which converts into an empty string. The start/end
2639 pointers in the original are not used further for this address, as
2640 it is the canonical extracted address which is all that is kept. */
2641
2642 case MAIL_CMD:
2643 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2644 was_rej_mail = TRUE; /* Reset if accepted */
2645
2646 if (helo_required && !helo_seen)
2647 {
2648 smtp_printf("503 HELO or EHLO required\r\n");
2649 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2650 "HELO/EHLO given", host_and_ident(FALSE));
2651 break;
2652 }
2653
2654 if (sender_address != NULL)
2655 {
2656 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2657 US"sender already given");
2658 break;
2659 }
2660
2661 if (smtp_command_argument[0] == 0)
2662 {
2663 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2664 US"MAIL must have an address operand");
2665 break;
2666 }
2667
2668 /* Check to see if the limit for messages per connection would be
2669 exceeded by accepting further messages. */
2670
2671 if (smtp_accept_max_per_connection > 0 &&
2672 smtp_mailcmd_count > smtp_accept_max_per_connection)
2673 {
2674 smtp_printf("421 too many messages in this connection\r\n");
2675 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2676 "messages in one connection", host_and_ident(TRUE));
2677 break;
2678 }
2679
2680 /* Reset for start of message - even if this is going to fail, we
2681 obviously need to throw away any previous data. */
2682
2683 smtp_reset(reset_point);
2684 toomany = FALSE;
2685 sender_data = recipient_data = NULL;
2686
2687 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2688
2689 if (esmtp) for(;;)
2690 {
2691 uschar *name, *value, *end;
2692 unsigned long int size;
2693
2694 if (!extract_option(&name, &value)) break;
2695
2696 /* Handle SIZE= by reading the value. We don't do the check till later,
2697 in order to be able to log the sender address on failure. */
2698
2699 if (strcmpic(name, US"SIZE") == 0 &&
2700 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2701 {
2702 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2703 size = INT_MAX;
2704 message_size = (int)size;
2705 }
2706
2707 /* If this session was initiated with EHLO and accept_8bitmime is set,
2708 Exim will have indicated that it supports the BODY=8BITMIME option. In
2709 fact, it does not support this according to the RFCs, in that it does not
2710 take any special action for forwarding messages containing 8-bit
2711 characters. That is why accept_8bitmime is not the default setting, but
2712 some sites want the action that is provided. We recognize both "8BITMIME"
2713 and "7BIT" as body types, but take no action. */
2714
2715 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2716 (strcmpic(value, US"8BITMIME") == 0 ||
2717 strcmpic(value, US"7BIT") == 0)) {}
2718
2719 /* Handle the AUTH extension. If the value given is not "<>" and either
2720 the ACL says "yes" or there is no ACL but the sending host is
2721 authenticated, we set it up as the authenticated sender. However, if the
2722 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2723 the condition is met. The value of AUTH is an xtext, which means that +,
2724 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2725 coding. */
2726
2727 else if (strcmpic(name, US"AUTH") == 0)
2728 {
2729 if (Ustrcmp(value, "<>") != 0)
2730 {
2731 int rc;
2732 uschar *ignore_msg;
2733
2734 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2735 {
2736 /* Put back terminator overrides for error message */
2737 name[-1] = ' ';
2738 value[-1] = '=';
2739 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2740 US"invalid data for AUTH");
2741 goto COMMAND_LOOP;
2742 }
2743
2744 if (acl_smtp_mailauth == NULL)
2745 {
2746 ignore_msg = US"client not authenticated";
2747 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2748 }
2749 else
2750 {
2751 ignore_msg = US"rejected by ACL";
2752 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2753 &user_msg, &log_msg);
2754 }
2755
2756 switch (rc)
2757 {
2758 case OK:
2759 if (authenticated_by == NULL ||
2760 authenticated_by->mail_auth_condition == NULL ||
2761 expand_check_condition(authenticated_by->mail_auth_condition,
2762 authenticated_by->name, US"authenticator"))
2763 break; /* Accept the AUTH */
2764
2765 ignore_msg = US"server_mail_auth_condition failed";
2766 if (authenticated_id != NULL)
2767 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2768 ignore_msg, authenticated_id);
2769
2770 /* Fall through */
2771
2772 case FAIL:
2773 authenticated_sender = NULL;
2774 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2775 value, host_and_ident(TRUE), ignore_msg);
2776 break;
2777
2778 /* Should only get DEFER or ERROR here. Put back terminator
2779 overrides for error message */
2780
2781 default:
2782 name[-1] = ' ';
2783 value[-1] = '=';
2784 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2785 log_msg);
2786 goto COMMAND_LOOP;
2787 }
2788 }
2789 }
2790
2791 /* Unknown option. Stick back the terminator characters and break
2792 the loop. An error for a malformed address will occur. */
2793
2794 else
2795 {
2796 name[-1] = ' ';
2797 value[-1] = '=';
2798 break;
2799 }
2800 }
2801
2802 /* If we have passed the threshold for rate limiting, apply the current
2803 delay, and update it for next time, provided this is a limited host. */
2804
2805 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2806 verify_check_host(&smtp_ratelimit_hosts) == OK)
2807 {
2808 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2809 smtp_delay_mail/1000.0);
2810 millisleep((int)smtp_delay_mail);
2811 smtp_delay_mail *= smtp_rlm_factor;
2812 if (smtp_delay_mail > (double)smtp_rlm_limit)
2813 smtp_delay_mail = (double)smtp_rlm_limit;
2814 }
2815
2816 /* Now extract the address, first applying any SMTP-time rewriting. The
2817 TRUE flag allows "<>" as a sender address. */
2818
2819 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2820 rewrite_one(smtp_command_argument, rewrite_smtp, NULL, FALSE, US"",
2821 global_rewrite_rules) : smtp_command_argument;
2822
2823 /* rfc821_domains = TRUE; << no longer needed */
2824 raw_sender =
2825 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2826 TRUE);
2827 /* rfc821_domains = FALSE; << no longer needed */
2828
2829 if (raw_sender == NULL)
2830 {
2831 done = synprot_error(L_smtp_syntax_error, 501, smtp_command_argument, errmess);
2832 break;
2833 }
2834
2835 sender_address = raw_sender;
2836
2837 /* If there is a configured size limit for mail, check that this message
2838 doesn't exceed it. The check is postponed to this point so that the sender
2839 can be logged. */
2840
2841 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2842 {
2843 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2844 log_write(L_size_reject,
2845 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2846 "message too big: size%s=%d max=%d",
2847 sender_address,
2848 host_and_ident(TRUE),
2849 (message_size == INT_MAX)? ">" : "",
2850 message_size,
2851 thismessage_size_limit);
2852 sender_address = NULL;
2853 break;
2854 }
2855
2856 /* Check there is enough space on the disk unless configured not to.
2857 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2858 plus the current message - i.e. we accept the message only if it won't
2859 reduce the space below the threshold. Add 5000 to the size to allow for
2860 overheads such as the Received: line and storing of recipients, etc.
2861 By putting the check here, even when SIZE is not given, it allow VRFY
2862 and EXPN etc. to be used when space is short. */
2863
2864 if (!receive_check_fs(
2865 (smtp_check_spool_space && message_size >= 0)?
2866 message_size + 5000 : 0))
2867 {
2868 smtp_printf("452 Space shortage, please try later\r\n");
2869 sender_address = NULL;
2870 break;
2871 }
2872
2873 /* If sender_address is unqualified, reject it, unless this is a locally
2874 generated message, or the sending host or net is permitted to send
2875 unqualified addresses - typically local machines behaving as MUAs -
2876 in which case just qualify the address. The flag is set above at the start
2877 of the SMTP connection. */
2878
2879 if (sender_domain == 0 && sender_address[0] != 0)
2880 {
2881 if (allow_unqualified_sender)
2882 {
2883 sender_domain = Ustrlen(sender_address) + 1;
2884 sender_address = rewrite_address_qualify(sender_address, FALSE);
2885 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2886 raw_sender);
2887 }
2888 else
2889 {
2890 smtp_printf("501 %s: sender address must contain a domain\r\n",
2891 smtp_command_argument);
2892 log_write(L_smtp_syntax_error,
2893 LOG_MAIN|LOG_REJECT,
2894 "unqualified sender rejected: <%s> %s%s",
2895 raw_sender,
2896 host_and_ident(TRUE),
2897 host_lookup_msg);
2898 sender_address = NULL;
2899 break;
2900 }
2901 }
2902
2903 /* Apply an ACL check if one is defined, before responding */
2904
2905 rc = (acl_smtp_mail == NULL)? OK :
2906 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2907
2908 if (rc == OK || rc == DISCARD)
2909 {
2910 smtp_printf("250 OK\r\n");
2911 smtp_delay_rcpt = smtp_rlr_base;
2912 recipients_discarded = (rc == DISCARD);
2913 was_rej_mail = FALSE;
2914 }
2915
2916 else
2917 {
2918 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2919 sender_address = NULL;
2920 }
2921 break;
2922
2923
2924 /* The RCPT command requires an address as an operand. All we do
2925 here is to parse it for syntactic correctness. There may be any number
2926 of RCPT commands, specifying multiple senders. We build them all into
2927 a data structure that is in argc/argv format. The start/end values
2928 given by parse_extract_address are not used, as we keep only the
2929 extracted address. */
2930
2931 case RCPT_CMD:
2932 rcpt_count++;
2933 was_rcpt = TRUE;
2934
2935 /* There must be a sender address; if the sender was rejected and
2936 pipelining was advertised, we assume the client was pipelining, and do not
2937 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2938 get the same treatment. */
2939
2940 if (sender_address == NULL)
2941 {
2942 if (pipelining_advertised && last_was_rej_mail)
2943 {
2944 smtp_printf("503 sender not yet given\r\n");
2945 was_rej_mail = TRUE;
2946 }
2947 else
2948 {
2949 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2950 US"sender not yet given");
2951 was_rcpt = FALSE; /* Not a valid RCPT */
2952 }
2953 rcpt_fail_count++;
2954 break;
2955 }
2956
2957 /* Check for an operand */
2958
2959 if (smtp_command_argument[0] == 0)
2960 {
2961 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2962 US"RCPT must have an address operand");
2963 rcpt_fail_count++;
2964 break;
2965 }
2966
2967 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2968 as a recipient address */
2969
2970 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2971 rewrite_one(smtp_command_argument, rewrite_smtp, NULL, FALSE, US"",
2972 global_rewrite_rules) : smtp_command_argument;
2973
2974 /* rfc821_domains = TRUE; << no longer needed */
2975 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2976 &recipient_domain, FALSE);
2977 /* rfc821_domains = FALSE; << no longer needed */
2978
2979 if (recipient == NULL)
2980 {
2981 done = synprot_error(L_smtp_syntax_error, 501, smtp_command_argument, errmess);
2982 rcpt_fail_count++;
2983 break;
2984 }
2985
2986 /* If the recipient address is unqualified, reject it, unless this is a
2987 locally generated message. However, unqualified addresses are permitted
2988 from a configured list of hosts and nets - typically when behaving as
2989 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2990 really. The flag is set at the start of the SMTP connection.
2991
2992 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2993 assumed this meant "reserved local part", but the revision of RFC 821 and
2994 friends now makes it absolutely clear that it means *mailbox*. Consequently
2995 we must always qualify this address, regardless. */
2996
2997 if (recipient_domain == 0)
2998 {
2999 if (allow_unqualified_recipient ||
3000 strcmpic(recipient, US"postmaster") == 0)
3001 {
3002 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3003 recipient);
3004 recipient_domain = Ustrlen(recipient) + 1;
3005 recipient = rewrite_address_qualify(recipient, TRUE);
3006 }
3007 else
3008 {
3009 rcpt_fail_count++;
3010 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3011 smtp_command_argument);
3012 log_write(L_smtp_syntax_error,
3013 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3014 "<%s> %s%s", recipient, host_and_ident(TRUE),
3015 host_lookup_msg);
3016 break;
3017 }
3018 }
3019
3020 /* Check maximum allowed */
3021
3022 if (rcpt_count > recipients_max && recipients_max > 0)
3023 {
3024 if (recipients_max_reject)
3025 {
3026 rcpt_fail_count++;
3027 smtp_printf("552 too many recipients\r\n");
3028 if (!toomany)
3029 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3030 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3031 }
3032 else
3033 {
3034 rcpt_defer_count++;
3035 smtp_printf("452 too many recipients\r\n");
3036 if (!toomany)
3037 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3038 "temporarily rejected: sender=<%s> %s", sender_address,
3039 host_and_ident(TRUE));
3040 }
3041
3042 toomany = TRUE;
3043 break;
3044 }
3045
3046 /* If we have passed the threshold for rate limiting, apply the current
3047 delay, and update it for next time, provided this is a limited host. */
3048
3049 if (rcpt_count > smtp_rlr_threshold &&
3050 verify_check_host(&smtp_ratelimit_hosts) == OK)
3051 {
3052 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3053 smtp_delay_rcpt/1000.0);
3054 millisleep((int)smtp_delay_rcpt);
3055 smtp_delay_rcpt *= smtp_rlr_factor;
3056 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3057 smtp_delay_rcpt = (double)smtp_rlr_limit;
3058 }
3059
3060 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3061 for them. Otherwise, check the access control list for this recipient. */
3062
3063 rc = recipients_discarded? DISCARD :
3064 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3065
3066 /* The ACL was happy */
3067
3068 if (rc == OK)
3069 {
3070 smtp_printf("250 Accepted\r\n");
3071 receive_add_recipient(recipient, -1);
3072 }
3073
3074 /* The recipient was discarded */
3075
3076 else if (rc == DISCARD)
3077 {
3078 smtp_printf("250 Accepted\r\n");
3079 rcpt_fail_count++;
3080 discarded = TRUE;
3081 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3082 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3083 (sender_address_unrewritten != NULL)?
3084 sender_address_unrewritten : sender_address,
3085 smtp_command_argument, recipients_discarded? "MAIL" : "RCPT",
3086 (log_msg == NULL)? US"" : US": ",
3087 (log_msg == NULL)? US"" : log_msg);
3088 }
3089
3090 /* Either the ACL failed the address, or it was deferred. */
3091
3092 else
3093 {
3094 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3095 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3096 }
3097 break;
3098
3099
3100 /* The DATA command is legal only if it follows successful MAIL FROM
3101 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3102 not counted as a protocol error if it follows RCPT (which must have been
3103 rejected if there are no recipients.) This function is complete when a
3104 valid DATA command is encountered.
3105
3106 Note concerning the code used: RFC 2821 says this:
3107
3108 - If there was no MAIL, or no RCPT, command, or all such commands
3109 were rejected, the server MAY return a "command out of sequence"
3110 (503) or "no valid recipients" (554) reply in response to the
3111 DATA command.
3112
3113 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3114 because it is the same whether pipelining is in use or not. */
3115
3116 case DATA_CMD:
3117 if (!discarded && recipients_count <= 0)
3118 {
3119 if (pipelining_advertised && last_was_rcpt)
3120 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3121 else
3122 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3123 US"valid RCPT command must precede DATA");
3124 break;
3125 }
3126
3127 if (toomany && recipients_max_reject)
3128 {
3129 sender_address = NULL; /* This will allow a new MAIL without RSET */
3130 sender_address_unrewritten = NULL;
3131 smtp_printf("554 Too many recipients\r\n");
3132 break;
3133 }
3134
3135 if (acl_smtp_predata == NULL) rc = OK; else
3136 {
3137 enable_dollar_recipients = TRUE;
3138 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3139 &log_msg);
3140 enable_dollar_recipients = FALSE;
3141 }
3142
3143 if (rc == OK)
3144 {
3145 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3146 done = 3;
3147 message_ended = END_NOTENDED; /* Indicate in middle of data */
3148 }
3149
3150 /* Either the ACL failed the address, or it was deferred. */
3151
3152 else
3153 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3154
3155 break;
3156
3157
3158 case VRFY_CMD:
3159 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3160 if (rc != OK)
3161 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3162 else
3163 {
3164 uschar *address;
3165 uschar *s = NULL;
3166
3167 /* rfc821_domains = TRUE; << no longer needed */
3168 address = parse_extract_address(smtp_command_argument, &errmess, &start, &end,
3169 &recipient_domain, FALSE);
3170 /* rfc821_domains = FALSE; << no longer needed */
3171
3172 if (address == NULL)
3173 s = string_sprintf("501 %s", errmess);
3174 else
3175 {
3176 address_item *addr = deliver_make_addr(address, FALSE);
3177 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3178 -1, -1, NULL, NULL, NULL))
3179 {
3180 case OK:
3181 s = string_sprintf("250 <%s> is deliverable", address);
3182 break;
3183
3184 case DEFER:
3185 s = (addr->message != NULL)?
3186 string_sprintf("451 <%s> %s", address, addr->message) :
3187 string_sprintf("451 Cannot resolve <%s> at this time", address);
3188 break;
3189
3190 case FAIL:
3191 s = (addr->message != NULL)?
3192 string_sprintf("550 <%s> %s", address, addr->message) :
3193 string_sprintf("550 <%s> is not deliverable", address);
3194 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3195 smtp_command_argument, host_and_ident(TRUE));
3196 break;
3197 }
3198 }
3199
3200 smtp_printf("%s\r\n", s);
3201 }
3202 break;
3203
3204
3205 case EXPN_CMD:
3206 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3207 if (rc != OK)
3208 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3209 else
3210 {
3211 BOOL save_log_testing_mode = log_testing_mode;
3212 address_test_mode = log_testing_mode = TRUE;
3213 (void) verify_address(deliver_make_addr(smtp_command_argument, FALSE),
3214 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3215 NULL, NULL, NULL);
3216 address_test_mode = FALSE;
3217 log_testing_mode = save_log_testing_mode; /* true for -bh */
3218 }
3219 break;
3220
3221
3222 #ifdef SUPPORT_TLS
3223
3224 case STARTTLS_CMD:
3225 if (!tls_advertised)
3226 {
3227 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3228 US"STARTTLS command used when not advertised");
3229 break;
3230 }
3231
3232 /* Apply an ACL check if one is defined */
3233
3234 if (acl_smtp_starttls != NULL)
3235 {
3236 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3237 &log_msg);
3238 if (rc != OK)
3239 {
3240 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3241 break;
3242 }
3243 }
3244
3245 /* RFC 2487 is not clear on when this command may be sent, though it
3246 does state that all information previously obtained from the client
3247 must be discarded if a TLS session is started. It seems reasonble to
3248 do an implied RSET when STARTTLS is received. */
3249
3250 incomplete_transaction_log(US"STARTTLS");
3251 smtp_reset(reset_point);
3252 toomany = FALSE;
3253 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3254
3255 /* Attempt to start up a TLS session, and if successful, discard all
3256 knowledge that was obtained previously. At least, that's what the RFC says,
3257 and that's what happens by default. However, in order to work round YAEB,
3258 there is an option to remember the esmtp state. Sigh.
3259
3260 We must allow for an extra EHLO command and an extra AUTH command after
3261 STARTTLS that don't add to the nonmail command count. */
3262
3263 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3264 {
3265 if (!tls_remember_esmtp)
3266 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3267 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3268 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3269 if (sender_helo_name != NULL)
3270 {
3271 store_free(sender_helo_name);
3272 sender_helo_name = NULL;
3273 host_build_sender_fullhost(); /* Rebuild */
3274 set_process_info("handling incoming TLS connection from %s",
3275 host_and_ident(FALSE));
3276 }
3277 received_protocol = (esmtp?
3278 protocols[pextend + pcrpted +
3279 ((sender_host_authenticated != NULL)? pauthed : 0)]
3280 :
3281 protocols[pnormal + pcrpted])
3282 +
3283 ((sender_host_address != NULL)? pnlocal : 0);
3284
3285 sender_host_authenticated = NULL;
3286 authenticated_id = NULL;
3287 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3288 DEBUG(D_tls) debug_printf("TLS active\n");
3289 break; /* Successful STARTTLS */
3290 }
3291
3292 /* Some local configuration problem was discovered before actually trying
3293 to do a TLS handshake; give a temporary error. */
3294
3295 else if (rc == DEFER)
3296 {
3297 smtp_printf("454 TLS currently unavailable\r\n");
3298 break;
3299 }
3300
3301 /* Hard failure. Reject everything except QUIT or closed connection. One
3302 cause for failure is a nested STARTTLS, in which case tls_active remains
3303 set, but we must still reject all incoming commands. */
3304
3305 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3306 while (done <= 0)
3307 {
3308 switch(smtp_read_command(FALSE))
3309 {
3310 case EOF_CMD:
3311 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3312 smtp_get_connection_info());
3313 done = 2;
3314 break;
3315
3316 case QUIT_CMD:
3317 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3318 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3319 smtp_get_connection_info());
3320 done = 2;
3321 break;
3322
3323 default:
3324 smtp_printf("554 Security failure\r\n");
3325 break;
3326 }
3327 }
3328 tls_close(TRUE);
3329 break;
3330 #endif
3331
3332
3333 /* The ACL for QUIT is provided for gathering statistical information or
3334 similar; it does not affect the response code, but it can supply a custom
3335 message. */
3336
3337 case QUIT_CMD:
3338 incomplete_transaction_log(US"QUIT");
3339
3340 if (acl_smtp_quit != NULL)
3341 {
3342 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit,&user_msg,&log_msg);
3343 if (rc == ERROR)
3344 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3345 log_msg);
3346 }
3347 else user_msg = NULL;
3348
3349 if (user_msg == NULL)
3350 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3351 else
3352 smtp_printf("221 %s\r\n", user_msg);
3353
3354 #ifdef SUPPORT_TLS
3355 tls_close(TRUE);
3356 #endif
3357
3358 done = 2;
3359 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3360 smtp_get_connection_info());
3361 break;
3362
3363
3364 case RSET_CMD:
3365 incomplete_transaction_log(US"RSET");
3366 smtp_reset(reset_point);
3367 toomany = FALSE;
3368 smtp_printf("250 Reset OK\r\n");
3369 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3370 break;
3371
3372
3373 case NOOP_CMD:
3374 smtp_printf("250 OK\r\n");
3375 break;
3376
3377
3378 /* Show ETRN/EXPN/VRFY if there's
3379 an ACL for checking hosts; if actually used, a check will be done for
3380 permitted hosts. */
3381
3382 case HELP_CMD:
3383 smtp_printf("214-Commands supported:\r\n");
3384 {
3385 uschar buffer[256];
3386 buffer[0] = 0;
3387 Ustrcat(buffer, " AUTH");
3388 #ifdef SUPPORT_TLS
3389 Ustrcat(buffer, " STARTTLS");
3390 #endif
3391 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3392 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3393 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3394 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3395 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3396 smtp_printf("214%s\r\n", buffer);
3397 }
3398 break;
3399
3400
3401 case EOF_CMD:
3402 incomplete_transaction_log(US"connection lost");
3403 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3404
3405 /* Don't log by default unless in the middle of a message, as some mailers
3406 just drop the call rather than sending QUIT, and it clutters up the logs.
3407 */
3408
3409 if (sender_address != NULL || recipients_count > 0)
3410 log_write(L_lost_incoming_connection,
3411 LOG_MAIN,
3412 "unexpected %s while reading SMTP command from %s%s",
3413 sender_host_unknown? "EOF" : "disconnection",
3414 host_and_ident(FALSE), smtp_read_error);
3415
3416 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3417 smtp_get_connection_info(), smtp_read_error);
3418
3419 done = 1;
3420 break;
3421
3422
3423 case ETRN_CMD:
3424 if (sender_address != NULL)
3425 {
3426 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3427 US"ETRN is not permitted inside a transaction");
3428 break;
3429 }
3430
3431 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_command_argument,
3432 host_and_ident(FALSE));
3433
3434 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
3435 if (rc != OK)
3436 {
3437 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3438 break;
3439 }
3440
3441 /* Compute the serialization key for this command. */
3442
3443 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_command_argument);
3444
3445 /* If a command has been specified for running as a result of ETRN, we
3446 permit any argument to ETRN. If not, only the # standard form is permitted,
3447 since that is strictly the only kind of ETRN that can be implemented
3448 according to the RFC. */
3449
3450 if (smtp_etrn_command != NULL)
3451 {
3452 uschar *error;
3453 BOOL rc;
3454 etrn_command = smtp_etrn_command;
3455 deliver_domain = smtp_command_argument;
3456 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3457 US"ETRN processing", &error);
3458 deliver_domain = NULL;
3459 if (!rc)
3460 {
3461 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3462 error);
3463 smtp_printf("458 Internal failure\r\n");
3464 break;
3465 }
3466 }
3467
3468 /* Else set up to call Exim with the -R option. */
3469
3470 else
3471 {
3472 if (*smtp_command_argument++ != '#')
3473 {
3474 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3475 US"argument must begin with #");
3476 break;
3477 }
3478 etrn_command = US"exim -R";
3479 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3480 smtp_command_argument);
3481 }
3482
3483 /* If we are host-testing, don't actually do anything. */
3484
3485 if (host_checking)
3486 {
3487 HDEBUG(D_any)
3488 {
3489 debug_printf("ETRN command is: %s\n", etrn_command);
3490 debug_printf("ETRN command execution skipped\n");
3491 }
3492 smtp_printf("250 OK\r\n");
3493 break;
3494 }
3495
3496
3497 /* If ETRN queue runs are to be serialized, check the database to
3498 ensure one isn't already running. */
3499
3500 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3501 {
3502 smtp_printf("458 Already processing %s\r\n", smtp_command_argument);
3503 break;
3504 }
3505
3506 /* Fork a child process and run the command. We don't want to have to
3507 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3508 forking. It should be set that way anyway for external incoming SMTP,
3509 but we save and restore to be tidy. If serialization is required, we
3510 actually run the command in yet another process, so we can wait for it
3511 to complete and then remove the serialization lock. */