Raise smtp_cmd_buffer_size to 16384.
[exim.git] / src / src / smtp_in.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2009 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8 /* Functions for handling an incoming SMTP call. */
9
10
11 #include "exim.h"
12
13
14 /* Initialize for TCP wrappers if so configured. It appears that the macro
15 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
16 including that header, and restore its value afterwards. */
17
18 #ifdef USE_TCP_WRAPPERS
19
20 #if HAVE_IPV6
21 #define EXIM_HAVE_IPV6
22 #endif
23 #undef HAVE_IPV6
24 #include <tcpd.h>
25 #undef HAVE_IPV6
26 #ifdef EXIM_HAVE_IPV6
27 #define HAVE_IPV6 TRUE
28 #endif
29
30 int allow_severity = LOG_INFO;
31 int deny_severity = LOG_NOTICE;
32 uschar *tcp_wrappers_name;
33 #endif
34
35
36 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
37 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
38 commands that accept arguments, and this in particular applies to AUTH, where
39 the data can be quite long. More recently this value was 2048 in Exim;
40 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
41 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
42 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
43 we need room to handle large base64-encoded AUTHs for GSSAPI.
44 */
45
46 #define smtp_cmd_buffer_size 16384
47
48 /* Size of buffer for reading SMTP incoming packets */
49
50 #define in_buffer_size 8192
51
52 /* Structure for SMTP command list */
53
54 typedef struct {
55 const char *name;
56 int len;
57 short int cmd;
58 short int has_arg;
59 short int is_mail_cmd;
60 } smtp_cmd_list;
61
62 /* Codes for identifying commands. We order them so that those that come first
63 are those for which synchronization is always required. Checking this can help
64 block some spam. */
65
66 enum {
67 /* These commands are required to be synchronized, i.e. to be the last in a
68 block of commands when pipelining. */
69
70 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
71 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
72 ETRN_CMD, /* This by analogy with TURN from the RFC */
73 STARTTLS_CMD, /* Required by the STARTTLS RFC */
74
75 /* This is a dummy to identify the non-sync commands when pipelining */
76
77 NON_SYNC_CMD_PIPELINING,
78
79 /* These commands need not be synchronized when pipelining */
80
81 MAIL_CMD, RCPT_CMD, RSET_CMD,
82
83 /* This is a dummy to identify the non-sync commands when not pipelining */
84
85 NON_SYNC_CMD_NON_PIPELINING,
86
87 /* I have been unable to find a statement about the use of pipelining
88 with AUTH, so to be on the safe side it is here, though I kind of feel
89 it should be up there with the synchronized commands. */
90
91 AUTH_CMD,
92
93 /* I'm not sure about these, but I don't think they matter. */
94
95 QUIT_CMD, HELP_CMD,
96
97 /* These are specials that don't correspond to actual commands */
98
99 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
100 TOO_MANY_NONMAIL_CMD };
101
102
103 /* This is a convenience macro for adding the identity of an SMTP command
104 to the circular buffer that holds a list of the last n received. */
105
106 #define HAD(n) \
107 smtp_connection_had[smtp_ch_index++] = n; \
108 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
109
110
111 /*************************************************
112 * Local static variables *
113 *************************************************/
114
115 static auth_instance *authenticated_by;
116 static BOOL auth_advertised;
117 #ifdef SUPPORT_TLS
118 static BOOL tls_advertised;
119 #endif
120 static BOOL esmtp;
121 static BOOL helo_required = FALSE;
122 static BOOL helo_verify = FALSE;
123 static BOOL helo_seen;
124 static BOOL helo_accept_junk;
125 static BOOL count_nonmail;
126 static BOOL pipelining_advertised;
127 static BOOL rcpt_smtp_response_same;
128 static BOOL rcpt_in_progress;
129 static int nonmail_command_count;
130 static BOOL smtp_exit_function_called = 0;
131 static int synprot_error_count;
132 static int unknown_command_count;
133 static int sync_cmd_limit;
134 static int smtp_write_error = 0;
135
136 static uschar *rcpt_smtp_response;
137 static uschar *smtp_data_buffer;
138 static uschar *smtp_cmd_data;
139
140 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
141 final fields of all except AUTH are forced TRUE at the start of a new message
142 setup, to allow one of each between messages that is not counted as a nonmail
143 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
144 allow a new EHLO after starting up TLS.
145
146 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
147 counted. However, the flag is changed when AUTH is received, so that multiple
148 failing AUTHs will eventually hit the limit. After a successful AUTH, another
149 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
150 forced TRUE, to allow for the re-authentication that can happen at that point.
151
152 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
153 count of non-mail commands and possibly provoke an error. */
154
155 static smtp_cmd_list cmd_list[] = {
156 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
157 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
158 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
159 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
160 #ifdef SUPPORT_TLS
161 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
162 #endif
163
164 /* If you change anything above here, also fix the definitions below. */
165
166 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
167 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
168 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
169 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
170 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
171 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
172 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
173 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
174 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
175 };
176
177 static smtp_cmd_list *cmd_list_end =
178 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
179
180 #define CMD_LIST_RSET 0
181 #define CMD_LIST_HELO 1
182 #define CMD_LIST_EHLO 2
183 #define CMD_LIST_AUTH 3
184 #define CMD_LIST_STARTTLS 4
185
186 /* This list of names is used for performing the smtp_no_mail logging action.
187 It must be kept in step with the SCH_xxx enumerations. */
188
189 static uschar *smtp_names[] =
190 {
191 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
192 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
193 US"VRFY" };
194
195 static uschar *protocols[] = {
196 US"local-smtp", /* HELO */
197 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
198 US"local-esmtp", /* EHLO */
199 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
200 US"local-esmtpa", /* EHLO->AUTH */
201 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
202 };
203
204 #define pnormal 0
205 #define pextend 2
206 #define pcrpted 1 /* added to pextend or pnormal */
207 #define pauthed 2 /* added to pextend */
208 #define pnlocal 6 /* offset to remove "local" */
209
210 /* When reading SMTP from a remote host, we have to use our own versions of the
211 C input-reading functions, in order to be able to flush the SMTP output only
212 when about to read more data from the socket. This is the only way to get
213 optimal performance when the client is using pipelining. Flushing for every
214 command causes a separate packet and reply packet each time; saving all the
215 responses up (when pipelining) combines them into one packet and one response.
216
217 For simplicity, these functions are used for *all* SMTP input, not only when
218 receiving over a socket. However, after setting up a secure socket (SSL), input
219 is read via the OpenSSL library, and another set of functions is used instead
220 (see tls.c).
221
222 These functions are set in the receive_getc etc. variables and called with the
223 same interface as the C functions. However, since there can only ever be
224 one incoming SMTP call, we just use a single buffer and flags. There is no need
225 to implement a complicated private FILE-like structure.*/
226
227 static uschar *smtp_inbuffer;
228 static uschar *smtp_inptr;
229 static uschar *smtp_inend;
230 static int smtp_had_eof;
231 static int smtp_had_error;
232
233
234 /*************************************************
235 * SMTP version of getc() *
236 *************************************************/
237
238 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
239 it flushes the output, and refills the buffer, with a timeout. The signal
240 handler is set appropriately by the calling function. This function is not used
241 after a connection has negotated itself into an TLS/SSL state.
242
243 Arguments: none
244 Returns: the next character or EOF
245 */
246
247 int
248 smtp_getc(void)
249 {
250 if (smtp_inptr >= smtp_inend)
251 {
252 int rc, save_errno;
253 fflush(smtp_out);
254 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
255 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
256 save_errno = errno;
257 alarm(0);
258 if (rc <= 0)
259 {
260 /* Must put the error text in fixed store, because this might be during
261 header reading, where it releases unused store above the header. */
262 if (rc < 0)
263 {
264 smtp_had_error = save_errno;
265 smtp_read_error = string_copy_malloc(
266 string_sprintf(" (error: %s)", strerror(save_errno)));
267 }
268 else smtp_had_eof = 1;
269 return EOF;
270 }
271 #ifndef DISABLE_DKIM
272 dkim_exim_verify_feed(smtp_inbuffer, rc);
273 #endif
274 smtp_inend = smtp_inbuffer + rc;
275 smtp_inptr = smtp_inbuffer;
276 }
277 return *smtp_inptr++;
278 }
279
280
281
282 /*************************************************
283 * SMTP version of ungetc() *
284 *************************************************/
285
286 /* Puts a character back in the input buffer. Only ever
287 called once.
288
289 Arguments:
290 ch the character
291
292 Returns: the character
293 */
294
295 int
296 smtp_ungetc(int ch)
297 {
298 *(--smtp_inptr) = ch;
299 return ch;
300 }
301
302
303
304
305 /*************************************************
306 * SMTP version of feof() *
307 *************************************************/
308
309 /* Tests for a previous EOF
310
311 Arguments: none
312 Returns: non-zero if the eof flag is set
313 */
314
315 int
316 smtp_feof(void)
317 {
318 return smtp_had_eof;
319 }
320
321
322
323
324 /*************************************************
325 * SMTP version of ferror() *
326 *************************************************/
327
328 /* Tests for a previous read error, and returns with errno
329 restored to what it was when the error was detected.
330
331 Arguments: none
332 Returns: non-zero if the error flag is set
333 */
334
335 int
336 smtp_ferror(void)
337 {
338 errno = smtp_had_error;
339 return smtp_had_error;
340 }
341
342
343
344 /*************************************************
345 * Test for characters in the SMTP buffer *
346 *************************************************/
347
348 /* Used at the end of a message
349
350 Arguments: none
351 Returns: TRUE/FALSE
352 */
353
354 BOOL
355 smtp_buffered(void)
356 {
357 return smtp_inptr < smtp_inend;
358 }
359
360
361
362 /*************************************************
363 * Write formatted string to SMTP channel *
364 *************************************************/
365
366 /* This is a separate function so that we don't have to repeat everything for
367 TLS support or debugging. It is global so that the daemon and the
368 authentication functions can use it. It does not return any error indication,
369 because major problems such as dropped connections won't show up till an output
370 flush for non-TLS connections. The smtp_fflush() function is available for
371 checking that: for convenience, TLS output errors are remembered here so that
372 they are also picked up later by smtp_fflush().
373
374 Arguments:
375 format format string
376 ... optional arguments
377
378 Returns: nothing
379 */
380
381 void
382 smtp_printf(const char *format, ...)
383 {
384 va_list ap;
385
386 va_start(ap, format);
387 smtp_vprintf(format, ap);
388 va_end(ap);
389 }
390
391 /* This is split off so that verify.c:respond_printf() can, in effect, call
392 smtp_printf(), bearing in mind that in C a vararg function can't directly
393 call another vararg function, only a function which accepts a va_list. */
394
395 void
396 smtp_vprintf(const char *format, va_list ap)
397 {
398 BOOL yield;
399
400 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
401
402 DEBUG(D_receive)
403 {
404 void *reset_point = store_get(0);
405 uschar *msg_copy, *cr, *end;
406 msg_copy = string_copy(big_buffer);
407 end = msg_copy + Ustrlen(msg_copy);
408 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
409 memmove(cr, cr + 1, (end--) - cr);
410 debug_printf("SMTP>> %s", msg_copy);
411 store_reset(reset_point);
412 }
413
414 if (!yield)
415 {
416 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
417 smtp_closedown(US"Unexpected error");
418 exim_exit(EXIT_FAILURE);
419 }
420
421 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
422 have had the same. Note: this code is also present in smtp_respond(). It would
423 be tidier to have it only in one place, but when it was added, it was easier to
424 do it that way, so as not to have to mess with the code for the RCPT command,
425 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
426
427 if (rcpt_in_progress)
428 {
429 if (rcpt_smtp_response == NULL)
430 rcpt_smtp_response = string_copy(big_buffer);
431 else if (rcpt_smtp_response_same &&
432 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
433 rcpt_smtp_response_same = FALSE;
434 rcpt_in_progress = FALSE;
435 }
436
437 /* Now write the string */
438
439 #ifdef SUPPORT_TLS
440 if (tls_active >= 0)
441 {
442 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
443 }
444 else
445 #endif
446
447 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
448 }
449
450
451
452 /*************************************************
453 * Flush SMTP out and check for error *
454 *************************************************/
455
456 /* This function isn't currently used within Exim (it detects errors when it
457 tries to read the next SMTP input), but is available for use in local_scan().
458 For non-TLS connections, it flushes the output and checks for errors. For
459 TLS-connections, it checks for a previously-detected TLS write error.
460
461 Arguments: none
462 Returns: 0 for no error; -1 after an error
463 */
464
465 int
466 smtp_fflush(void)
467 {
468 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
469 return smtp_write_error;
470 }
471
472
473
474 /*************************************************
475 * SMTP command read timeout *
476 *************************************************/
477
478 /* Signal handler for timing out incoming SMTP commands. This attempts to
479 finish off tidily.
480
481 Argument: signal number (SIGALRM)
482 Returns: nothing
483 */
484
485 static void
486 command_timeout_handler(int sig)
487 {
488 sig = sig; /* Keep picky compilers happy */
489 log_write(L_lost_incoming_connection,
490 LOG_MAIN, "SMTP command timeout on%s connection from %s",
491 (tls_active >= 0)? " TLS" : "",
492 host_and_ident(FALSE));
493 if (smtp_batched_input)
494 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
495 smtp_notquit_exit(US"command-timeout", US"421",
496 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
497 exim_exit(EXIT_FAILURE);
498 }
499
500
501
502 /*************************************************
503 * SIGTERM received *
504 *************************************************/
505
506 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
507
508 Argument: signal number (SIGTERM)
509 Returns: nothing
510 */
511
512 static void
513 command_sigterm_handler(int sig)
514 {
515 sig = sig; /* Keep picky compilers happy */
516 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
517 if (smtp_batched_input)
518 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
519 smtp_notquit_exit(US"signal-exit", US"421",
520 US"%s: Service not available - closing connection", smtp_active_hostname);
521 exim_exit(EXIT_FAILURE);
522 }
523
524
525
526
527 /*************************************************
528 * Read one command line *
529 *************************************************/
530
531 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
532 There are sites that don't do this, and in any case internal SMTP probably
533 should check only for LF. Consequently, we check here for LF only. The line
534 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
535 an unknown command. The command is read into the global smtp_cmd_buffer so that
536 it is available via $smtp_command.
537
538 The character reading routine sets up a timeout for each block actually read
539 from the input (which may contain more than one command). We set up a special
540 signal handler that closes down the session on a timeout. Control does not
541 return when it runs.
542
543 Arguments:
544 check_sync if TRUE, check synchronization rules if global option is TRUE
545
546 Returns: a code identifying the command (enumerated above)
547 */
548
549 static int
550 smtp_read_command(BOOL check_sync)
551 {
552 int c;
553 int ptr = 0;
554 smtp_cmd_list *p;
555 BOOL hadnull = FALSE;
556
557 os_non_restarting_signal(SIGALRM, command_timeout_handler);
558
559 while ((c = (receive_getc)()) != '\n' && c != EOF)
560 {
561 if (ptr >= smtp_cmd_buffer_size)
562 {
563 os_non_restarting_signal(SIGALRM, sigalrm_handler);
564 return OTHER_CMD;
565 }
566 if (c == 0)
567 {
568 hadnull = TRUE;
569 c = '?';
570 }
571 smtp_cmd_buffer[ptr++] = c;
572 }
573
574 receive_linecount++; /* For BSMTP errors */
575 os_non_restarting_signal(SIGALRM, sigalrm_handler);
576
577 /* If hit end of file, return pseudo EOF command. Whether we have a
578 part-line already read doesn't matter, since this is an error state. */
579
580 if (c == EOF) return EOF_CMD;
581
582 /* Remove any CR and white space at the end of the line, and terminate the
583 string. */
584
585 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
586 smtp_cmd_buffer[ptr] = 0;
587
588 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
589
590 /* NULLs are not allowed in SMTP commands */
591
592 if (hadnull) return BADCHAR_CMD;
593
594 /* Scan command list and return identity, having set the data pointer
595 to the start of the actual data characters. Check for SMTP synchronization
596 if required. */
597
598 for (p = cmd_list; p < cmd_list_end; p++)
599 {
600 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
601 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
602 smtp_cmd_buffer[p->len] == 0 ||
603 smtp_cmd_buffer[p->len] == ' '))
604 {
605 if (smtp_inptr < smtp_inend && /* Outstanding input */
606 p->cmd < sync_cmd_limit && /* Command should sync */
607 check_sync && /* Local flag set */
608 smtp_enforce_sync && /* Global flag set */
609 sender_host_address != NULL && /* Not local input */
610 !sender_host_notsocket) /* Really is a socket */
611 return BADSYN_CMD;
612
613 /* The variables $smtp_command and $smtp_command_argument point into the
614 unmodified input buffer. A copy of the latter is taken for actual
615 processing, so that it can be chopped up into separate parts if necessary,
616 for example, when processing a MAIL command options such as SIZE that can
617 follow the sender address. */
618
619 smtp_cmd_argument = smtp_cmd_buffer + p->len;
620 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
621 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
622 smtp_cmd_data = smtp_data_buffer;
623
624 /* Count non-mail commands from those hosts that are controlled in this
625 way. The default is all hosts. We don't waste effort checking the list
626 until we get a non-mail command, but then cache the result to save checking
627 again. If there's a DEFER while checking the host, assume it's in the list.
628
629 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
630 start of each incoming message by fiddling with the value in the table. */
631
632 if (!p->is_mail_cmd)
633 {
634 if (count_nonmail == TRUE_UNSET) count_nonmail =
635 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
636 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
637 return TOO_MANY_NONMAIL_CMD;
638 }
639
640 /* If there is data for a command that does not expect it, generate the
641 error here. */
642
643 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
644 }
645 }
646
647 /* Enforce synchronization for unknown commands */
648
649 if (smtp_inptr < smtp_inend && /* Outstanding input */
650 check_sync && /* Local flag set */
651 smtp_enforce_sync && /* Global flag set */
652 sender_host_address != NULL && /* Not local input */
653 !sender_host_notsocket) /* Really is a socket */
654 return BADSYN_CMD;
655
656 return OTHER_CMD;
657 }
658
659
660
661 /*************************************************
662 * Recheck synchronization *
663 *************************************************/
664
665 /* Synchronization checks can never be perfect because a packet may be on its
666 way but not arrived when the check is done. Such checks can in any case only be
667 done when TLS is not in use. Normally, the checks happen when commands are
668 read: Exim ensures that there is no more input in the input buffer. In normal
669 cases, the response to the command will be fast, and there is no further check.
670
671 However, for some commands an ACL is run, and that can include delays. In those
672 cases, it is useful to do another check on the input just before sending the
673 response. This also applies at the start of a connection. This function does
674 that check by means of the select() function, as long as the facility is not
675 disabled or inappropriate. A failure of select() is ignored.
676
677 When there is unwanted input, we read it so that it appears in the log of the
678 error.
679
680 Arguments: none
681 Returns: TRUE if all is well; FALSE if there is input pending
682 */
683
684 static BOOL
685 check_sync(void)
686 {
687 int fd, rc;
688 fd_set fds;
689 struct timeval tzero;
690
691 if (!smtp_enforce_sync || sender_host_address == NULL ||
692 sender_host_notsocket || tls_active >= 0)
693 return TRUE;
694
695 fd = fileno(smtp_in);
696 FD_ZERO(&fds);
697 FD_SET(fd, &fds);
698 tzero.tv_sec = 0;
699 tzero.tv_usec = 0;
700 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
701
702 if (rc <= 0) return TRUE; /* Not ready to read */
703 rc = smtp_getc();
704 if (rc < 0) return TRUE; /* End of file or error */
705
706 smtp_ungetc(rc);
707 rc = smtp_inend - smtp_inptr;
708 if (rc > 150) rc = 150;
709 smtp_inptr[rc] = 0;
710 return FALSE;
711 }
712
713
714
715 /*************************************************
716 * Forced closedown of call *
717 *************************************************/
718
719 /* This function is called from log.c when Exim is dying because of a serious
720 disaster, and also from some other places. If an incoming non-batched SMTP
721 channel is open, it swallows the rest of the incoming message if in the DATA
722 phase, sends the reply string, and gives an error to all subsequent commands
723 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
724 smtp_in.
725
726 Arguments:
727 message SMTP reply string to send, excluding the code
728
729 Returns: nothing
730 */
731
732 void
733 smtp_closedown(uschar *message)
734 {
735 if (smtp_in == NULL || smtp_batched_input) return;
736 receive_swallow_smtp();
737 smtp_printf("421 %s\r\n", message);
738
739 for (;;)
740 {
741 switch(smtp_read_command(FALSE))
742 {
743 case EOF_CMD:
744 return;
745
746 case QUIT_CMD:
747 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
748 mac_smtp_fflush();
749 return;
750
751 case RSET_CMD:
752 smtp_printf("250 Reset OK\r\n");
753 break;
754
755 default:
756 smtp_printf("421 %s\r\n", message);
757 break;
758 }
759 }
760 }
761
762
763
764
765 /*************************************************
766 * Set up connection info for logging *
767 *************************************************/
768
769 /* This function is called when logging information about an SMTP connection.
770 It sets up appropriate source information, depending on the type of connection.
771 If sender_fullhost is NULL, we are at a very early stage of the connection;
772 just use the IP address.
773
774 Argument: none
775 Returns: a string describing the connection
776 */
777
778 uschar *
779 smtp_get_connection_info(void)
780 {
781 uschar *hostname = (sender_fullhost == NULL)?
782 sender_host_address : sender_fullhost;
783
784 if (host_checking)
785 return string_sprintf("SMTP connection from %s", hostname);
786
787 if (sender_host_unknown || sender_host_notsocket)
788 return string_sprintf("SMTP connection from %s", sender_ident);
789
790 if (is_inetd)
791 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
792
793 if ((log_extra_selector & LX_incoming_interface) != 0 &&
794 interface_address != NULL)
795 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
796 interface_address, interface_port);
797
798 return string_sprintf("SMTP connection from %s", hostname);
799 }
800
801
802
803 /*************************************************
804 * Log lack of MAIL if so configured *
805 *************************************************/
806
807 /* This function is called when an SMTP session ends. If the log selector
808 smtp_no_mail is set, write a log line giving some details of what has happened
809 in the SMTP session.
810
811 Arguments: none
812 Returns: nothing
813 */
814
815 void
816 smtp_log_no_mail(void)
817 {
818 int size, ptr, i;
819 uschar *s, *sep;
820
821 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
822 return;
823
824 s = NULL;
825 size = ptr = 0;
826
827 if (sender_host_authenticated != NULL)
828 {
829 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
830 if (authenticated_id != NULL)
831 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
832 }
833
834 #ifdef SUPPORT_TLS
835 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_cipher != NULL)
836 s = string_append(s, &size, &ptr, 2, US" X=", tls_cipher);
837 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
838 tls_cipher != NULL)
839 s = string_append(s, &size, &ptr, 2, US" CV=",
840 tls_certificate_verified? "yes":"no");
841 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_peerdn != NULL)
842 s = string_append(s, &size, &ptr, 3, US" DN=\"",
843 string_printing(tls_peerdn), US"\"");
844 #endif
845
846 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
847 US" C=..." : US" C=";
848 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
849 {
850 if (smtp_connection_had[i] != SCH_NONE)
851 {
852 s = string_append(s, &size, &ptr, 2, sep,
853 smtp_names[smtp_connection_had[i]]);
854 sep = US",";
855 }
856 }
857
858 for (i = 0; i < smtp_ch_index; i++)
859 {
860 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
861 sep = US",";
862 }
863
864 if (s != NULL) s[ptr] = 0; else s = US"";
865 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
866 host_and_ident(FALSE),
867 readconf_printtime(time(NULL) - smtp_connection_start), s);
868 }
869
870
871
872 /*************************************************
873 * Check HELO line and set sender_helo_name *
874 *************************************************/
875
876 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
877 the domain name of the sending host, or an ip literal in square brackets. The
878 arrgument is placed in sender_helo_name, which is in malloc store, because it
879 must persist over multiple incoming messages. If helo_accept_junk is set, this
880 host is permitted to send any old junk (needed for some broken hosts).
881 Otherwise, helo_allow_chars can be used for rogue characters in general
882 (typically people want to let in underscores).
883
884 Argument:
885 s the data portion of the line (already past any white space)
886
887 Returns: TRUE or FALSE
888 */
889
890 static BOOL
891 check_helo(uschar *s)
892 {
893 uschar *start = s;
894 uschar *end = s + Ustrlen(s);
895 BOOL yield = helo_accept_junk;
896
897 /* Discard any previous helo name */
898
899 if (sender_helo_name != NULL)
900 {
901 store_free(sender_helo_name);
902 sender_helo_name = NULL;
903 }
904
905 /* Skip tests if junk is permitted. */
906
907 if (!yield)
908 {
909 /* Allow the new standard form for IPv6 address literals, namely,
910 [IPv6:....], and because someone is bound to use it, allow an equivalent
911 IPv4 form. Allow plain addresses as well. */
912
913 if (*s == '[')
914 {
915 if (end[-1] == ']')
916 {
917 end[-1] = 0;
918 if (strncmpic(s, US"[IPv6:", 6) == 0)
919 yield = (string_is_ip_address(s+6, NULL) == 6);
920 else if (strncmpic(s, US"[IPv4:", 6) == 0)
921 yield = (string_is_ip_address(s+6, NULL) == 4);
922 else
923 yield = (string_is_ip_address(s+1, NULL) != 0);
924 end[-1] = ']';
925 }
926 }
927
928 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
929 that have been configured (usually underscore - sigh). */
930
931 else if (*s != 0)
932 {
933 yield = TRUE;
934 while (*s != 0)
935 {
936 if (!isalnum(*s) && *s != '.' && *s != '-' &&
937 Ustrchr(helo_allow_chars, *s) == NULL)
938 {
939 yield = FALSE;
940 break;
941 }
942 s++;
943 }
944 }
945 }
946
947 /* Save argument if OK */
948
949 if (yield) sender_helo_name = string_copy_malloc(start);
950 return yield;
951 }
952
953
954
955
956
957 /*************************************************
958 * Extract SMTP command option *
959 *************************************************/
960
961 /* This function picks the next option setting off the end of smtp_cmd_data. It
962 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
963 things that can appear there.
964
965 Arguments:
966 name point this at the name
967 value point this at the data string
968
969 Returns: TRUE if found an option
970 */
971
972 static BOOL
973 extract_option(uschar **name, uschar **value)
974 {
975 uschar *n;
976 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
977 while (isspace(*v)) v--;
978 v[1] = 0;
979
980 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
981 if (*v != '=') return FALSE;
982
983 n = v;
984 while(isalpha(n[-1])) n--;
985
986 if (n[-1] != ' ') return FALSE;
987
988 n[-1] = 0;
989 *name = n;
990 *v++ = 0;
991 *value = v;
992 return TRUE;
993 }
994
995
996
997
998
999 /*************************************************
1000 * Reset for new message *
1001 *************************************************/
1002
1003 /* This function is called whenever the SMTP session is reset from
1004 within either of the setup functions.
1005
1006 Argument: the stacking pool storage reset point
1007 Returns: nothing
1008 */
1009
1010 static void
1011 smtp_reset(void *reset_point)
1012 {
1013 store_reset(reset_point);
1014 recipients_list = NULL;
1015 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1016 raw_recipients_count = recipients_count = recipients_list_max = 0;
1017 message_linecount = 0;
1018 message_size = -1;
1019 acl_added_headers = NULL;
1020 queue_only_policy = FALSE;
1021 rcpt_smtp_response = NULL;
1022 rcpt_smtp_response_same = TRUE;
1023 rcpt_in_progress = FALSE;
1024 deliver_freeze = FALSE; /* Can be set by ACL */
1025 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1026 fake_response = OK; /* Can be set by ACL */
1027 #ifdef WITH_CONTENT_SCAN
1028 no_mbox_unspool = FALSE; /* Can be set by ACL */
1029 #endif
1030 submission_mode = FALSE; /* Can be set by ACL */
1031 suppress_local_fixups = FALSE; /* Can be set by ACL */
1032 active_local_from_check = local_from_check; /* Can be set by ACL */
1033 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1034 sender_address = NULL;
1035 submission_name = NULL; /* Can be set by ACL */
1036 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1037 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1038 sender_verified_list = NULL; /* No senders verified */
1039 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1040 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1041 authenticated_sender = NULL;
1042 #ifdef EXPERIMENTAL_BRIGHTMAIL
1043 bmi_run = 0;
1044 bmi_verdicts = NULL;
1045 #endif
1046 #ifndef DISABLE_DKIM
1047 dkim_signers = NULL;
1048 dkim_disable_verify = FALSE;
1049 dkim_collect_input = FALSE;
1050 #endif
1051 #ifdef EXPERIMENTAL_SPF
1052 spf_header_comment = NULL;
1053 spf_received = NULL;
1054 spf_result = NULL;
1055 spf_smtp_comment = NULL;
1056 #endif
1057 body_linecount = body_zerocount = 0;
1058
1059 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1060 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1061 /* Note that ratelimiters_conn persists across resets. */
1062
1063 /* Reset message ACL variables */
1064
1065 acl_var_m = NULL;
1066
1067 /* The message body variables use malloc store. They may be set if this is
1068 not the first message in an SMTP session and the previous message caused them
1069 to be referenced in an ACL. */
1070
1071 if (message_body != NULL)
1072 {
1073 store_free(message_body);
1074 message_body = NULL;
1075 }
1076
1077 if (message_body_end != NULL)
1078 {
1079 store_free(message_body_end);
1080 message_body_end = NULL;
1081 }
1082
1083 /* Warning log messages are also saved in malloc store. They are saved to avoid
1084 repetition in the same message, but it seems right to repeat them for different
1085 messages. */
1086
1087 while (acl_warn_logged != NULL)
1088 {
1089 string_item *this = acl_warn_logged;
1090 acl_warn_logged = acl_warn_logged->next;
1091 store_free(this);
1092 }
1093 }
1094
1095
1096
1097
1098
1099 /*************************************************
1100 * Initialize for incoming batched SMTP message *
1101 *************************************************/
1102
1103 /* This function is called from smtp_setup_msg() in the case when
1104 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1105 of messages in one file with SMTP commands between them. All errors must be
1106 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1107 relevant. After an error on a sender, or an invalid recipient, the remainder
1108 of the message is skipped. The value of received_protocol is already set.
1109
1110 Argument: none
1111 Returns: > 0 message successfully started (reached DATA)
1112 = 0 QUIT read or end of file reached
1113 < 0 should not occur
1114 */
1115
1116 static int
1117 smtp_setup_batch_msg(void)
1118 {
1119 int done = 0;
1120 void *reset_point = store_get(0);
1121
1122 /* Save the line count at the start of each transaction - single commands
1123 like HELO and RSET count as whole transactions. */
1124
1125 bsmtp_transaction_linecount = receive_linecount;
1126
1127 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1128
1129 smtp_reset(reset_point); /* Reset for start of message */
1130
1131 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1132 value. The values are 2 larger than the required yield of the function. */
1133
1134 while (done <= 0)
1135 {
1136 uschar *errmess;
1137 uschar *recipient = NULL;
1138 int start, end, sender_domain, recipient_domain;
1139
1140 switch(smtp_read_command(FALSE))
1141 {
1142 /* The HELO/EHLO commands set sender_address_helo if they have
1143 valid data; otherwise they are ignored, except that they do
1144 a reset of the state. */
1145
1146 case HELO_CMD:
1147 case EHLO_CMD:
1148
1149 check_helo(smtp_cmd_data);
1150 /* Fall through */
1151
1152 case RSET_CMD:
1153 smtp_reset(reset_point);
1154 bsmtp_transaction_linecount = receive_linecount;
1155 break;
1156
1157
1158 /* The MAIL FROM command requires an address as an operand. All we
1159 do here is to parse it for syntactic correctness. The form "<>" is
1160 a special case which converts into an empty string. The start/end
1161 pointers in the original are not used further for this address, as
1162 it is the canonical extracted address which is all that is kept. */
1163
1164 case MAIL_CMD:
1165 if (sender_address != NULL)
1166 /* The function moan_smtp_batch() does not return. */
1167 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1168
1169 if (smtp_cmd_data[0] == 0)
1170 /* The function moan_smtp_batch() does not return. */
1171 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1172
1173 /* Reset to start of message */
1174
1175 smtp_reset(reset_point);
1176
1177 /* Apply SMTP rewrite */
1178
1179 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1180 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1181 US"", global_rewrite_rules) : smtp_cmd_data;
1182
1183 /* Extract the address; the TRUE flag allows <> as valid */
1184
1185 raw_sender =
1186 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1187 TRUE);
1188
1189 if (raw_sender == NULL)
1190 /* The function moan_smtp_batch() does not return. */
1191 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1192
1193 sender_address = string_copy(raw_sender);
1194
1195 /* Qualify unqualified sender addresses if permitted to do so. */
1196
1197 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1198 {
1199 if (allow_unqualified_sender)
1200 {
1201 sender_address = rewrite_address_qualify(sender_address, FALSE);
1202 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1203 "and rewritten\n", raw_sender);
1204 }
1205 /* The function moan_smtp_batch() does not return. */
1206 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1207 "a domain");
1208 }
1209 break;
1210
1211
1212 /* The RCPT TO command requires an address as an operand. All we do
1213 here is to parse it for syntactic correctness. There may be any number
1214 of RCPT TO commands, specifying multiple senders. We build them all into
1215 a data structure that is in argc/argv format. The start/end values
1216 given by parse_extract_address are not used, as we keep only the
1217 extracted address. */
1218
1219 case RCPT_CMD:
1220 if (sender_address == NULL)
1221 /* The function moan_smtp_batch() does not return. */
1222 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1223
1224 if (smtp_cmd_data[0] == 0)
1225 /* The function moan_smtp_batch() does not return. */
1226 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1227
1228 /* Check maximum number allowed */
1229
1230 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1231 /* The function moan_smtp_batch() does not return. */
1232 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1233 recipients_max_reject? "552": "452");
1234
1235 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1236 recipient address */
1237
1238 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1239 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1240 global_rewrite_rules) : smtp_cmd_data;
1241
1242 /* rfc821_domains = TRUE; << no longer needed */
1243 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1244 &recipient_domain, FALSE);
1245 /* rfc821_domains = FALSE; << no longer needed */
1246
1247 if (recipient == NULL)
1248 /* The function moan_smtp_batch() does not return. */
1249 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1250
1251 /* If the recipient address is unqualified, qualify it if permitted. Then
1252 add it to the list of recipients. */
1253
1254 if (recipient_domain == 0)
1255 {
1256 if (allow_unqualified_recipient)
1257 {
1258 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1259 recipient);
1260 recipient = rewrite_address_qualify(recipient, TRUE);
1261 }
1262 /* The function moan_smtp_batch() does not return. */
1263 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1264 "a domain");
1265 }
1266 receive_add_recipient(recipient, -1);
1267 break;
1268
1269
1270 /* The DATA command is legal only if it follows successful MAIL FROM
1271 and RCPT TO commands. This function is complete when a valid DATA
1272 command is encountered. */
1273
1274 case DATA_CMD:
1275 if (sender_address == NULL || recipients_count <= 0)
1276 {
1277 /* The function moan_smtp_batch() does not return. */
1278 if (sender_address == NULL)
1279 moan_smtp_batch(smtp_cmd_buffer,
1280 "503 MAIL FROM:<sender> command must precede DATA");
1281 else
1282 moan_smtp_batch(smtp_cmd_buffer,
1283 "503 RCPT TO:<recipient> must precede DATA");
1284 }
1285 else
1286 {
1287 done = 3; /* DATA successfully achieved */
1288 message_ended = END_NOTENDED; /* Indicate in middle of message */
1289 }
1290 break;
1291
1292
1293 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1294
1295 case VRFY_CMD:
1296 case EXPN_CMD:
1297 case HELP_CMD:
1298 case NOOP_CMD:
1299 case ETRN_CMD:
1300 bsmtp_transaction_linecount = receive_linecount;
1301 break;
1302
1303
1304 case EOF_CMD:
1305 case QUIT_CMD:
1306 done = 2;
1307 break;
1308
1309
1310 case BADARG_CMD:
1311 /* The function moan_smtp_batch() does not return. */
1312 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1313 break;
1314
1315
1316 case BADCHAR_CMD:
1317 /* The function moan_smtp_batch() does not return. */
1318 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1319 break;
1320
1321
1322 default:
1323 /* The function moan_smtp_batch() does not return. */
1324 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1325 break;
1326 }
1327 }
1328
1329 return done - 2; /* Convert yield values */
1330 }
1331
1332
1333
1334
1335 /*************************************************
1336 * Start an SMTP session *
1337 *************************************************/
1338
1339 /* This function is called at the start of an SMTP session. Thereafter,
1340 smtp_setup_msg() is called to initiate each separate message. This
1341 function does host-specific testing, and outputs the banner line.
1342
1343 Arguments: none
1344 Returns: FALSE if the session can not continue; something has
1345 gone wrong, or the connection to the host is blocked
1346 */
1347
1348 BOOL
1349 smtp_start_session(void)
1350 {
1351 int size = 256;
1352 int ptr, esclen;
1353 uschar *user_msg, *log_msg;
1354 uschar *code, *esc;
1355 uschar *p, *s, *ss;
1356
1357 smtp_connection_start = time(NULL);
1358 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1359 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1360 smtp_ch_index = 0;
1361
1362 /* Default values for certain variables */
1363
1364 helo_seen = esmtp = helo_accept_junk = FALSE;
1365 smtp_mailcmd_count = 0;
1366 count_nonmail = TRUE_UNSET;
1367 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1368 smtp_delay_mail = smtp_rlm_base;
1369 auth_advertised = FALSE;
1370 pipelining_advertised = FALSE;
1371 pipelining_enable = TRUE;
1372 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1373 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1374
1375 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1376
1377 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1378 authentication settings from -oMaa to remain in force. */
1379
1380 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1381 authenticated_by = NULL;
1382
1383 #ifdef SUPPORT_TLS
1384 tls_cipher = tls_peerdn = NULL;
1385 tls_advertised = FALSE;
1386 #endif
1387
1388 /* Reset ACL connection variables */
1389
1390 acl_var_c = NULL;
1391
1392 /* Allow for trailing 0 in the command and data buffers. */
1393
1394 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1395 if (smtp_cmd_buffer == NULL)
1396 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1397 "malloc() failed for SMTP command buffer");
1398 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1399
1400 /* For batched input, the protocol setting can be overridden from the
1401 command line by a trusted caller. */
1402
1403 if (smtp_batched_input)
1404 {
1405 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1406 }
1407
1408 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1409 reset later if any of EHLO/AUTH/STARTTLS are received. */
1410
1411 else
1412 received_protocol =
1413 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1414
1415 /* Set up the buffer for inputting using direct read() calls, and arrange to
1416 call the local functions instead of the standard C ones. */
1417
1418 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1419 if (smtp_inbuffer == NULL)
1420 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1421 receive_getc = smtp_getc;
1422 receive_ungetc = smtp_ungetc;
1423 receive_feof = smtp_feof;
1424 receive_ferror = smtp_ferror;
1425 receive_smtp_buffered = smtp_buffered;
1426 smtp_inptr = smtp_inend = smtp_inbuffer;
1427 smtp_had_eof = smtp_had_error = 0;
1428
1429 /* Set up the message size limit; this may be host-specific */
1430
1431 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1432 if (expand_string_message != NULL)
1433 {
1434 if (thismessage_size_limit == -1)
1435 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1436 "%s", expand_string_message);
1437 else
1438 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1439 "%s", expand_string_message);
1440 smtp_closedown(US"Temporary local problem - please try later");
1441 return FALSE;
1442 }
1443
1444 /* When a message is input locally via the -bs or -bS options, sender_host_
1445 unknown is set unless -oMa was used to force an IP address, in which case it
1446 is checked like a real remote connection. When -bs is used from inetd, this
1447 flag is not set, causing the sending host to be checked. The code that deals
1448 with IP source routing (if configured) is never required for -bs or -bS and
1449 the flag sender_host_notsocket is used to suppress it.
1450
1451 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1452 reserve for certain hosts and/or networks. */
1453
1454 if (!sender_host_unknown)
1455 {
1456 int rc;
1457 BOOL reserved_host = FALSE;
1458
1459 /* Look up IP options (source routing info) on the socket if this is not an
1460 -oMa "host", and if any are found, log them and drop the connection.
1461
1462 Linux (and others now, see below) is different to everyone else, so there
1463 has to be some conditional compilation here. Versions of Linux before 2.1.15
1464 used a structure whose name was "options". Somebody finally realized that
1465 this name was silly, and it got changed to "ip_options". I use the
1466 newer name here, but there is a fudge in the script that sets up os.h
1467 to define a macro in older Linux systems.
1468
1469 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1470 glibc 2, which has chosen ip_opts for the structure name. This is now
1471 really a glibc thing rather than a Linux thing, so the condition name
1472 has been changed to reflect this. It is relevant also to GNU/Hurd.
1473
1474 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1475 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1476 a special macro defined in the os.h file.
1477
1478 Some DGUX versions on older hardware appear not to support IP options at
1479 all, so there is now a general macro which can be set to cut out this
1480 support altogether.
1481
1482 How to do this properly in IPv6 is not yet known. */
1483
1484 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1485
1486 #ifdef GLIBC_IP_OPTIONS
1487 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1488 #define OPTSTYLE 1
1489 #else
1490 #define OPTSTYLE 2
1491 #endif
1492 #elif defined DARWIN_IP_OPTIONS
1493 #define OPTSTYLE 2
1494 #else
1495 #define OPTSTYLE 3
1496 #endif
1497
1498 if (!host_checking && !sender_host_notsocket)
1499 {
1500 #if OPTSTYLE == 1
1501 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1502 struct ip_options *ipopt = store_get(optlen);
1503 #elif OPTSTYLE == 2
1504 struct ip_opts ipoptblock;
1505 struct ip_opts *ipopt = &ipoptblock;
1506 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1507 #else
1508 struct ipoption ipoptblock;
1509 struct ipoption *ipopt = &ipoptblock;
1510 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1511 #endif
1512
1513 /* Occasional genuine failures of getsockopt() have been seen - for
1514 example, "reset by peer". Therefore, just log and give up on this
1515 call, unless the error is ENOPROTOOPT. This error is given by systems
1516 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1517 of writing. So for that error, carry on - we just can't do an IP options
1518 check. */
1519
1520 DEBUG(D_receive) debug_printf("checking for IP options\n");
1521
1522 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1523 &optlen) < 0)
1524 {
1525 if (errno != ENOPROTOOPT)
1526 {
1527 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1528 host_and_ident(FALSE), strerror(errno));
1529 smtp_printf("451 SMTP service not available\r\n");
1530 return FALSE;
1531 }
1532 }
1533
1534 /* Deal with any IP options that are set. On the systems I have looked at,
1535 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1536 more logging data than will fit in big_buffer. Nevertheless, after somebody
1537 questioned this code, I've added in some paranoid checking. */
1538
1539 else if (optlen > 0)
1540 {
1541 uschar *p = big_buffer;
1542 uschar *pend = big_buffer + big_buffer_size;
1543 uschar *opt, *adptr;
1544 int optcount;
1545 struct in_addr addr;
1546
1547 #if OPTSTYLE == 1
1548 uschar *optstart = (uschar *)(ipopt->__data);
1549 #elif OPTSTYLE == 2
1550 uschar *optstart = (uschar *)(ipopt->ip_opts);
1551 #else
1552 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1553 #endif
1554
1555 DEBUG(D_receive) debug_printf("IP options exist\n");
1556
1557 Ustrcpy(p, "IP options on incoming call:");
1558 p += Ustrlen(p);
1559
1560 for (opt = optstart; opt != NULL &&
1561 opt < (uschar *)(ipopt) + optlen;)
1562 {
1563 switch (*opt)
1564 {
1565 case IPOPT_EOL:
1566 opt = NULL;
1567 break;
1568
1569 case IPOPT_NOP:
1570 opt++;
1571 break;
1572
1573 case IPOPT_SSRR:
1574 case IPOPT_LSRR:
1575 if (!string_format(p, pend-p, " %s [@%s",
1576 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1577 #if OPTSTYLE == 1
1578 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1579 #elif OPTSTYLE == 2
1580 inet_ntoa(ipopt->ip_dst)))
1581 #else
1582 inet_ntoa(ipopt->ipopt_dst)))
1583 #endif
1584 {
1585 opt = NULL;
1586 break;
1587 }
1588
1589 p += Ustrlen(p);
1590 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1591 adptr = opt + 3;
1592 while (optcount-- > 0)
1593 {
1594 memcpy(&addr, adptr, sizeof(addr));
1595 if (!string_format(p, pend - p - 1, "%s%s",
1596 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1597 {
1598 opt = NULL;
1599 break;
1600 }
1601 p += Ustrlen(p);
1602 adptr += sizeof(struct in_addr);
1603 }
1604 *p++ = ']';
1605 opt += opt[1];
1606 break;
1607
1608 default:
1609 {
1610 int i;
1611 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1612 Ustrcat(p, "[ ");
1613 p += 2;
1614 for (i = 0; i < opt[1]; i++)
1615 {
1616 sprintf(CS p, "%2.2x ", opt[i]);
1617 p += 3;
1618 }
1619 *p++ = ']';
1620 }
1621 opt += opt[1];
1622 break;
1623 }
1624 }
1625
1626 *p = 0;
1627 log_write(0, LOG_MAIN, "%s", big_buffer);
1628
1629 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1630
1631 log_write(0, LOG_MAIN|LOG_REJECT,
1632 "connection from %s refused (IP options)", host_and_ident(FALSE));
1633
1634 smtp_printf("554 SMTP service not available\r\n");
1635 return FALSE;
1636 }
1637
1638 /* Length of options = 0 => there are no options */
1639
1640 else DEBUG(D_receive) debug_printf("no IP options found\n");
1641 }
1642 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1643
1644 /* Set keep-alive in socket options. The option is on by default. This
1645 setting is an attempt to get rid of some hanging connections that stick in
1646 read() when the remote end (usually a dialup) goes away. */
1647
1648 if (smtp_accept_keepalive && !sender_host_notsocket)
1649 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1650
1651 /* If the current host matches host_lookup, set the name by doing a
1652 reverse lookup. On failure, sender_host_name will be NULL and
1653 host_lookup_failed will be TRUE. This may or may not be serious - optional
1654 checks later. */
1655
1656 if (verify_check_host(&host_lookup) == OK)
1657 {
1658 (void)host_name_lookup();
1659 host_build_sender_fullhost();
1660 }
1661
1662 /* Delay this until we have the full name, if it is looked up. */
1663
1664 set_process_info("handling incoming connection from %s",
1665 host_and_ident(FALSE));
1666
1667 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1668 smtps port for use with older style SSL MTAs. */
1669
1670 #ifdef SUPPORT_TLS
1671 if (tls_on_connect &&
1672 tls_server_start(tls_require_ciphers,
1673 gnutls_require_mac, gnutls_require_kx, gnutls_require_proto) != OK)
1674 return FALSE;
1675 #endif
1676
1677 /* Test for explicit connection rejection */
1678
1679 if (verify_check_host(&host_reject_connection) == OK)
1680 {
1681 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1682 "from %s (host_reject_connection)", host_and_ident(FALSE));
1683 smtp_printf("554 SMTP service not available\r\n");
1684 return FALSE;
1685 }
1686
1687 /* Test with TCP Wrappers if so configured. There is a problem in that
1688 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1689 such as disks dying. In these cases, it is desirable to reject with a 4xx
1690 error instead of a 5xx error. There isn't a "right" way to detect such
1691 problems. The following kludge is used: errno is zeroed before calling
1692 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1693 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1694 not exist). */
1695
1696 #ifdef USE_TCP_WRAPPERS
1697 errno = 0;
1698 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
1699 if (tcp_wrappers_name == NULL)
1700 {
1701 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
1702 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
1703 expand_string_message);
1704 }
1705 if (!hosts_ctl(tcp_wrappers_name,
1706 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1707 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1708 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1709 {
1710 if (errno == 0 || errno == ENOENT)
1711 {
1712 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1713 log_write(L_connection_reject,
1714 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1715 "(tcp wrappers)", host_and_ident(FALSE));
1716 smtp_printf("554 SMTP service not available\r\n");
1717 }
1718 else
1719 {
1720 int save_errno = errno;
1721 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1722 "errno value %d\n", save_errno);
1723 log_write(L_connection_reject,
1724 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1725 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1726 smtp_printf("451 Temporary local problem - please try later\r\n");
1727 }
1728 return FALSE;
1729 }
1730 #endif
1731
1732 /* Check for reserved slots. The value of smtp_accept_count has already been
1733 incremented to include this process. */
1734
1735 if (smtp_accept_max > 0 &&
1736 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
1737 {
1738 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1739 {
1740 log_write(L_connection_reject,
1741 LOG_MAIN, "temporarily refused connection from %s: not in "
1742 "reserve list: connected=%d max=%d reserve=%d%s",
1743 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
1744 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1745 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1746 "please try again later\r\n", smtp_active_hostname);
1747 return FALSE;
1748 }
1749 reserved_host = TRUE;
1750 }
1751
1752 /* If a load level above which only messages from reserved hosts are
1753 accepted is set, check the load. For incoming calls via the daemon, the
1754 check is done in the superior process if there are no reserved hosts, to
1755 save a fork. In all cases, the load average will already be available
1756 in a global variable at this point. */
1757
1758 if (smtp_load_reserve >= 0 &&
1759 load_average > smtp_load_reserve &&
1760 !reserved_host &&
1761 verify_check_host(&smtp_reserve_hosts) != OK)
1762 {
1763 log_write(L_connection_reject,
1764 LOG_MAIN, "temporarily refused connection from %s: not in "
1765 "reserve list and load average = %.2f", host_and_ident(FALSE),
1766 (double)load_average/1000.0);
1767 smtp_printf("421 %s: Too much load; please try again later\r\n",
1768 smtp_active_hostname);
1769 return FALSE;
1770 }
1771
1772 /* Determine whether unqualified senders or recipients are permitted
1773 for this host. Unfortunately, we have to do this every time, in order to
1774 set the flags so that they can be inspected when considering qualifying
1775 addresses in the headers. For a site that permits no qualification, this
1776 won't take long, however. */
1777
1778 allow_unqualified_sender =
1779 verify_check_host(&sender_unqualified_hosts) == OK;
1780
1781 allow_unqualified_recipient =
1782 verify_check_host(&recipient_unqualified_hosts) == OK;
1783
1784 /* Determine whether HELO/EHLO is required for this host. The requirement
1785 can be hard or soft. */
1786
1787 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1788 if (!helo_required)
1789 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1790
1791 /* Determine whether this hosts is permitted to send syntactic junk
1792 after a HELO or EHLO command. */
1793
1794 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1795 }
1796
1797 /* For batch SMTP input we are now done. */
1798
1799 if (smtp_batched_input) return TRUE;
1800
1801 /* Run the ACL if it exists */
1802
1803 user_msg = NULL;
1804 if (acl_smtp_connect != NULL)
1805 {
1806 int rc;
1807 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1808 &log_msg);
1809 if (rc != OK)
1810 {
1811 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1812 return FALSE;
1813 }
1814 }
1815
1816 /* Output the initial message for a two-way SMTP connection. It may contain
1817 newlines, which then cause a multi-line response to be given. */
1818
1819 code = US"220"; /* Default status code */
1820 esc = US""; /* Default extended status code */
1821 esclen = 0; /* Length of esc */
1822
1823 if (user_msg == NULL)
1824 {
1825 s = expand_string(smtp_banner);
1826 if (s == NULL)
1827 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1828 "failed: %s", smtp_banner, expand_string_message);
1829 }
1830 else
1831 {
1832 int codelen = 3;
1833 s = user_msg;
1834 smtp_message_code(&code, &codelen, &s, NULL);
1835 if (codelen > 4)
1836 {
1837 esc = code + 4;
1838 esclen = codelen - 4;
1839 }
1840 }
1841
1842 /* Remove any terminating newlines; might as well remove trailing space too */
1843
1844 p = s + Ustrlen(s);
1845 while (p > s && isspace(p[-1])) p--;
1846 *p = 0;
1847
1848 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1849 is all contained in a single IP packet. The original code wrote out the
1850 greeting using several calls to fprint/fputc, and on busy servers this could
1851 cause it to be split over more than one packet - which caused CC:Mail to fall
1852 over when it got the second part of the greeting after sending its first
1853 command. Sigh. To try to avoid this, build the complete greeting message
1854 first, and output it in one fell swoop. This gives a better chance of it
1855 ending up as a single packet. */
1856
1857 ss = store_get(size);
1858 ptr = 0;
1859
1860 p = s;
1861 do /* At least once, in case we have an empty string */
1862 {
1863 int len;
1864 uschar *linebreak = Ustrchr(p, '\n');
1865 ss = string_cat(ss, &size, &ptr, code, 3);
1866 if (linebreak == NULL)
1867 {
1868 len = Ustrlen(p);
1869 ss = string_cat(ss, &size, &ptr, US" ", 1);
1870 }
1871 else
1872 {
1873 len = linebreak - p;
1874 ss = string_cat(ss, &size, &ptr, US"-", 1);
1875 }
1876 ss = string_cat(ss, &size, &ptr, esc, esclen);
1877 ss = string_cat(ss, &size, &ptr, p, len);
1878 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1879 p += len;
1880 if (linebreak != NULL) p++;
1881 }
1882 while (*p != 0);
1883
1884 ss[ptr] = 0; /* string_cat leaves room for this */
1885
1886 /* Before we write the banner, check that there is no input pending, unless
1887 this synchronisation check is disabled. */
1888
1889 if (!check_sync())
1890 {
1891 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1892 "synchronization error (input sent without waiting for greeting): "
1893 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1894 string_printing(smtp_inptr));
1895 smtp_printf("554 SMTP synchronization error\r\n");
1896 return FALSE;
1897 }
1898
1899 /* Now output the banner */
1900
1901 smtp_printf("%s", ss);
1902 return TRUE;
1903 }
1904
1905
1906
1907
1908
1909 /*************************************************
1910 * Handle SMTP syntax and protocol errors *
1911 *************************************************/
1912
1913 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1914 to do so. Then transmit the error response. The return value depends on the
1915 number of syntax and protocol errors in this SMTP session.
1916
1917 Arguments:
1918 type error type, given as a log flag bit
1919 code response code; <= 0 means don't send a response
1920 data data to reflect in the response (can be NULL)
1921 errmess the error message
1922
1923 Returns: -1 limit of syntax/protocol errors NOT exceeded
1924 +1 limit of syntax/protocol errors IS exceeded
1925
1926 These values fit in with the values of the "done" variable in the main
1927 processing loop in smtp_setup_msg(). */
1928
1929 static int
1930 synprot_error(int type, int code, uschar *data, uschar *errmess)
1931 {
1932 int yield = -1;
1933
1934 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1935 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1936 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1937
1938 if (++synprot_error_count > smtp_max_synprot_errors)
1939 {
1940 yield = 1;
1941 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1942 "syntax or protocol errors (last command was \"%s\")",
1943 host_and_ident(FALSE), smtp_cmd_buffer);
1944 }
1945
1946 if (code > 0)
1947 {
1948 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1949 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1950 if (yield == 1)
1951 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1952 }
1953
1954 return yield;
1955 }
1956
1957
1958
1959
1960 /*************************************************
1961 * Log incomplete transactions *
1962 *************************************************/
1963
1964 /* This function is called after a transaction has been aborted by RSET, QUIT,
1965 connection drops or other errors. It logs the envelope information received
1966 so far in order to preserve address verification attempts.
1967
1968 Argument: string to indicate what aborted the transaction
1969 Returns: nothing
1970 */
1971
1972 static void
1973 incomplete_transaction_log(uschar *what)
1974 {
1975 if (sender_address == NULL || /* No transaction in progress */
1976 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1977 ) return;
1978
1979 /* Build list of recipients for logging */
1980
1981 if (recipients_count > 0)
1982 {
1983 int i;
1984 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1985 for (i = 0; i < recipients_count; i++)
1986 raw_recipients[i] = recipients_list[i].address;
1987 raw_recipients_count = recipients_count;
1988 }
1989
1990 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1991 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1992 }
1993
1994
1995
1996
1997 /*************************************************
1998 * Send SMTP response, possibly multiline *
1999 *************************************************/
2000
2001 /* There are, it seems, broken clients out there that cannot handle multiline
2002 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2003 output nothing for non-final calls, and only the first line for anything else.
2004
2005 Arguments:
2006 code SMTP code, may involve extended status codes
2007 codelen length of smtp code; if > 4 there's an ESC
2008 final FALSE if the last line isn't the final line
2009 msg message text, possibly containing newlines
2010
2011 Returns: nothing
2012 */
2013
2014 void
2015 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2016 {
2017 int esclen = 0;
2018 uschar *esc = US"";
2019
2020 if (!final && no_multiline_responses) return;
2021
2022 if (codelen > 4)
2023 {
2024 esc = code + 4;
2025 esclen = codelen - 4;
2026 }
2027
2028 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2029 have had the same. Note: this code is also present in smtp_printf(). It would
2030 be tidier to have it only in one place, but when it was added, it was easier to
2031 do it that way, so as not to have to mess with the code for the RCPT command,
2032 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2033
2034 if (rcpt_in_progress)
2035 {
2036 if (rcpt_smtp_response == NULL)
2037 rcpt_smtp_response = string_copy(msg);
2038 else if (rcpt_smtp_response_same &&
2039 Ustrcmp(rcpt_smtp_response, msg) != 0)
2040 rcpt_smtp_response_same = FALSE;
2041 rcpt_in_progress = FALSE;
2042 }
2043
2044 /* Not output the message, splitting it up into multiple lines if necessary. */
2045
2046 for (;;)
2047 {
2048 uschar *nl = Ustrchr(msg, '\n');
2049 if (nl == NULL)
2050 {
2051 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2052 return;
2053 }
2054 else if (nl[1] == 0 || no_multiline_responses)
2055 {
2056 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2057 (int)(nl - msg), msg);
2058 return;
2059 }
2060 else
2061 {
2062 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2063 msg = nl + 1;
2064 while (isspace(*msg)) msg++;
2065 }
2066 }
2067 }
2068
2069
2070
2071
2072 /*************************************************
2073 * Parse user SMTP message *
2074 *************************************************/
2075
2076 /* This function allows for user messages overriding the response code details
2077 by providing a suitable response code string at the start of the message
2078 user_msg. Check the message for starting with a response code and optionally an
2079 extended status code. If found, check that the first digit is valid, and if so,
2080 change the code pointer and length to use the replacement. An invalid code
2081 causes a panic log; in this case, if the log messages is the same as the user
2082 message, we must also adjust the value of the log message to show the code that
2083 is actually going to be used (the original one).
2084
2085 This function is global because it is called from receive.c as well as within
2086 this module.
2087
2088 Note that the code length returned includes the terminating whitespace
2089 character, which is always included in the regex match.
2090
2091 Arguments:
2092 code SMTP code, may involve extended status codes
2093 codelen length of smtp code; if > 4 there's an ESC
2094 msg message text
2095 log_msg optional log message, to be adjusted with the new SMTP code
2096
2097 Returns: nothing
2098 */
2099
2100 void
2101 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2102 {
2103 int n;
2104 int ovector[3];
2105
2106 if (msg == NULL || *msg == NULL) return;
2107
2108 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2109 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2110 if (n < 0) return;
2111
2112 if ((*msg)[0] != (*code)[0])
2113 {
2114 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2115 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2116 if (log_msg != NULL && *log_msg == *msg)
2117 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2118 }
2119 else
2120 {
2121 *code = *msg;
2122 *codelen = ovector[1]; /* Includes final space */
2123 }
2124 *msg += ovector[1]; /* Chop the code off the message */
2125 return;
2126 }
2127
2128
2129
2130
2131 /*************************************************
2132 * Handle an ACL failure *
2133 *************************************************/
2134
2135 /* This function is called when acl_check() fails. As well as calls from within
2136 this module, it is called from receive.c for an ACL after DATA. It sorts out
2137 logging the incident, and sets up the error response. A message containing
2138 newlines is turned into a multiline SMTP response, but for logging, only the
2139 first line is used.
2140
2141 There's a table of default permanent failure response codes to use in
2142 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2143 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2144 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2145 state, because there are broken clients that try VRFY before RCPT. A 5xx
2146 response should be given only when the address is positively known to be
2147 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2148 503.
2149
2150 From Exim 4.63, it is possible to override the response code details by
2151 providing a suitable response code string at the start of the message provided
2152 in user_msg. The code's first digit is checked for validity.
2153
2154 Arguments:
2155 where where the ACL was called from
2156 rc the failure code
2157 user_msg a message that can be included in an SMTP response
2158 log_msg a message for logging
2159
2160 Returns: 0 in most cases
2161 2 if the failure code was FAIL_DROP, in which case the
2162 SMTP connection should be dropped (this value fits with the
2163 "done" variable in smtp_setup_msg() below)
2164 */
2165
2166 int
2167 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2168 {
2169 BOOL drop = rc == FAIL_DROP;
2170 int codelen = 3;
2171 uschar *smtp_code;
2172 uschar *lognl;
2173 uschar *sender_info = US"";
2174 uschar *what =
2175 #ifdef WITH_CONTENT_SCAN
2176 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2177 #endif
2178 (where == ACL_WHERE_PREDATA)? US"DATA" :
2179 (where == ACL_WHERE_DATA)? US"after DATA" :
2180 (smtp_cmd_data == NULL)?
2181 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2182 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2183
2184 if (drop) rc = FAIL;
2185
2186 /* Set the default SMTP code, and allow a user message to change it. */
2187
2188 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2189 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2190
2191 /* We used to have sender_address here; however, there was a bug that was not
2192 updating sender_address after a rewrite during a verify. When this bug was
2193 fixed, sender_address at this point became the rewritten address. I'm not sure
2194 this is what should be logged, so I've changed to logging the unrewritten
2195 address to retain backward compatibility. */
2196
2197 #ifndef WITH_CONTENT_SCAN
2198 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2199 #else
2200 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2201 #endif
2202 {
2203 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
2204 sender_address_unrewritten : sender_address);
2205 }
2206
2207 /* If there's been a sender verification failure with a specific message, and
2208 we have not sent a response about it yet, do so now, as a preliminary line for
2209 failures, but not defers. However, always log it for defer, and log it for fail
2210 unless the sender_verify_fail log selector has been turned off. */
2211
2212 if (sender_verified_failed != NULL &&
2213 !testflag(sender_verified_failed, af_sverify_told))
2214 {
2215 BOOL save_rcpt_in_progress = rcpt_in_progress;
2216 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2217
2218 setflag(sender_verified_failed, af_sverify_told);
2219
2220 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2221 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2222 host_and_ident(TRUE),
2223 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2224 sender_verified_failed->address,
2225 (sender_verified_failed->message == NULL)? US"" :
2226 string_sprintf(": %s", sender_verified_failed->message));
2227
2228 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2229 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2230 testflag(sender_verified_failed, af_verify_pmfail)?
2231 "Postmaster verification failed while checking <%s>\n%s\n"
2232 "Several RFCs state that you are required to have a postmaster\n"
2233 "mailbox for each mail domain. This host does not accept mail\n"
2234 "from domains whose servers reject the postmaster address."
2235 :
2236 testflag(sender_verified_failed, af_verify_nsfail)?
2237 "Callback setup failed while verifying <%s>\n%s\n"
2238 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2239 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2240 "RFC requirements, and stops you from receiving standard bounce\n"
2241 "messages. This host does not accept mail from domains whose servers\n"
2242 "refuse bounces."
2243 :
2244 "Verification failed for <%s>\n%s",
2245 sender_verified_failed->address,
2246 sender_verified_failed->user_message));
2247
2248 rcpt_in_progress = save_rcpt_in_progress;
2249 }
2250
2251 /* Sort out text for logging */
2252
2253 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2254 lognl = Ustrchr(log_msg, '\n');
2255 if (lognl != NULL) *lognl = 0;
2256
2257 /* Send permanent failure response to the command, but the code used isn't
2258 always a 5xx one - see comments at the start of this function. If the original
2259 rc was FAIL_DROP we drop the connection and yield 2. */
2260
2261 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2262 US"Administrative prohibition" : user_msg);
2263
2264 /* Send temporary failure response to the command. Don't give any details,
2265 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2266 verb, and for a header verify when smtp_return_error_details is set.
2267
2268 This conditional logic is all somewhat of a mess because of the odd
2269 interactions between temp_details and return_error_details. One day it should
2270 be re-implemented in a tidier fashion. */
2271
2272 else
2273 {
2274 if (acl_temp_details && user_msg != NULL)
2275 {
2276 if (smtp_return_error_details &&
2277 sender_verified_failed != NULL &&
2278 sender_verified_failed->message != NULL)
2279 {
2280 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2281 }
2282 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2283 }
2284 else
2285 smtp_respond(smtp_code, codelen, TRUE,
2286 US"Temporary local problem - please try later");
2287 }
2288
2289 /* Log the incident to the logs that are specified by log_reject_target
2290 (default main, reject). This can be empty to suppress logging of rejections. If
2291 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2292 is closing if required and return 2. */
2293
2294 if (log_reject_target != 0)
2295 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2296 host_and_ident(TRUE),
2297 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2298
2299 if (!drop) return 0;
2300
2301 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2302 smtp_get_connection_info());
2303
2304 /* Run the not-quit ACL, but without any custom messages. This should not be a
2305 problem, because we get here only if some other ACL has issued "drop", and
2306 in that case, *its* custom messages will have been used above. */
2307
2308 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2309 return 2;
2310 }
2311
2312
2313
2314
2315 /*************************************************
2316 * Handle SMTP exit when QUIT is not given *
2317 *************************************************/
2318
2319 /* This function provides a logging/statistics hook for when an SMTP connection
2320 is dropped on the floor or the other end goes away. It's a global function
2321 because it's called from receive.c as well as this module. As well as running
2322 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2323 response, either with a custom message from the ACL, or using a default. There
2324 is one case, however, when no message is output - after "drop". In that case,
2325 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2326 passed to this function.
2327
2328 In case things go wrong while processing this function, causing an error that
2329 may re-enter this funtion, there is a recursion check.
2330
2331 Arguments:
2332 reason What $smtp_notquit_reason will be set to in the ACL;
2333 if NULL, the ACL is not run
2334 code The error code to return as part of the response
2335 defaultrespond The default message if there's no user_msg
2336
2337 Returns: Nothing
2338 */
2339
2340 void
2341 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2342 {
2343 int rc;
2344 uschar *user_msg = NULL;
2345 uschar *log_msg = NULL;
2346
2347 /* Check for recursive acll */
2348
2349 if (smtp_exit_function_called)
2350 {
2351 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2352 reason);
2353 return;
2354 }
2355 smtp_exit_function_called = TRUE;
2356
2357 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2358
2359 if (acl_smtp_notquit != NULL && reason != NULL)
2360 {
2361 smtp_notquit_reason = reason;
2362 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2363 &log_msg);
2364 if (rc == ERROR)
2365 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2366 log_msg);
2367 }
2368
2369 /* Write an SMTP response if we are expected to give one. As the default
2370 responses are all internal, they should always fit in the buffer, but code a
2371 warning, just in case. Note that string_vformat() still leaves a complete
2372 string, even if it is incomplete. */
2373
2374 if (code != NULL && defaultrespond != NULL)
2375 {
2376 if (user_msg == NULL)
2377 {
2378 uschar buffer[128];
2379 va_list ap;
2380 va_start(ap, defaultrespond);
2381 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2382 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2383 smtp_printf("%s %s\r\n", code, buffer);
2384 va_end(ap);
2385 }
2386 else
2387 smtp_respond(code, 3, TRUE, user_msg);
2388 mac_smtp_fflush();
2389 }
2390 }
2391
2392
2393
2394
2395 /*************************************************
2396 * Verify HELO argument *
2397 *************************************************/
2398
2399 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2400 matched. It is also called from ACL processing if verify = helo is used and
2401 verification was not previously tried (i.e. helo_try_verify_hosts was not
2402 matched). The result of its processing is to set helo_verified and
2403 helo_verify_failed. These variables should both be FALSE for this function to
2404 be called.
2405
2406 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2407 for IPv6 ::ffff: literals.
2408
2409 Argument: none
2410 Returns: TRUE if testing was completed;
2411 FALSE on a temporary failure
2412 */
2413
2414 BOOL
2415 smtp_verify_helo(void)
2416 {
2417 BOOL yield = TRUE;
2418
2419 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2420 sender_helo_name);
2421
2422 if (sender_helo_name == NULL)
2423 {
2424 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2425 }
2426
2427 /* Deal with the case of -bs without an IP address */
2428
2429 else if (sender_host_address == NULL)
2430 {
2431 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2432 helo_verified = TRUE;
2433 }
2434
2435 /* Deal with the more common case when there is a sending IP address */
2436
2437 else if (sender_helo_name[0] == '[')
2438 {
2439 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2440 Ustrlen(sender_host_address)) == 0;
2441
2442 #if HAVE_IPV6
2443 if (!helo_verified)
2444 {
2445 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2446 helo_verified = Ustrncmp(sender_helo_name + 1,
2447 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2448 }
2449 #endif
2450
2451 HDEBUG(D_receive)
2452 { if (helo_verified) debug_printf("matched host address\n"); }
2453 }
2454
2455 /* Do a reverse lookup if one hasn't already given a positive or negative
2456 response. If that fails, or the name doesn't match, try checking with a forward
2457 lookup. */
2458
2459 else
2460 {
2461 if (sender_host_name == NULL && !host_lookup_failed)
2462 yield = host_name_lookup() != DEFER;
2463
2464 /* If a host name is known, check it and all its aliases. */
2465
2466 if (sender_host_name != NULL)
2467 {
2468 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2469
2470 if (helo_verified)
2471 {
2472 HDEBUG(D_receive) debug_printf("matched host name\n");
2473 }
2474 else
2475 {
2476 uschar **aliases = sender_host_aliases;
2477 while (*aliases != NULL)
2478 {
2479 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2480 if (helo_verified) break;
2481 }
2482 HDEBUG(D_receive)
2483 {
2484 if (helo_verified)
2485 debug_printf("matched alias %s\n", *(--aliases));
2486 }
2487 }
2488 }
2489
2490 /* Final attempt: try a forward lookup of the helo name */
2491
2492 if (!helo_verified)
2493 {
2494 int rc;
2495 host_item h;
2496 h.name = sender_helo_name;
2497 h.address = NULL;
2498 h.mx = MX_NONE;
2499 h.next = NULL;
2500 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2501 sender_helo_name);
2502 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2503 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2504 {
2505 host_item *hh = &h;
2506 while (hh != NULL)
2507 {
2508 if (Ustrcmp(hh->address, sender_host_address) == 0)
2509 {
2510 helo_verified = TRUE;
2511 HDEBUG(D_receive)
2512 debug_printf("IP address for %s matches calling address\n",
2513 sender_helo_name);
2514 break;
2515 }
2516 hh = hh->next;
2517 }
2518 }
2519 }
2520 }
2521
2522 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2523 return yield;
2524 }
2525
2526
2527
2528
2529 /*************************************************
2530 * Send user response message *
2531 *************************************************/
2532
2533 /* This function is passed a default response code and a user message. It calls
2534 smtp_message_code() to check and possibly modify the response code, and then
2535 calls smtp_respond() to transmit the response. I put this into a function
2536 just to avoid a lot of repetition.
2537
2538 Arguments:
2539 code the response code
2540 user_msg the user message
2541
2542 Returns: nothing
2543 */
2544
2545 static void
2546 smtp_user_msg(uschar *code, uschar *user_msg)
2547 {
2548 int len = 3;
2549 smtp_message_code(&code, &len, &user_msg, NULL);
2550 smtp_respond(code, len, TRUE, user_msg);
2551 }
2552
2553
2554
2555
2556 /*************************************************
2557 * Initialize for SMTP incoming message *
2558 *************************************************/
2559
2560 /* This function conducts the initial dialogue at the start of an incoming SMTP
2561 message, and builds a list of recipients. However, if the incoming message
2562 is part of a batch (-bS option) a separate function is called since it would
2563 be messy having tests splattered about all over this function. This function
2564 therefore handles the case where interaction is occurring. The input and output
2565 files are set up in smtp_in and smtp_out.
2566
2567 The global recipients_list is set to point to a vector of recipient_item
2568 blocks, whose number is given by recipients_count. This is extended by the
2569 receive_add_recipient() function. The global variable sender_address is set to
2570 the sender's address. The yield is +1 if a message has been successfully
2571 started, 0 if a QUIT command was encountered or the connection was refused from
2572 the particular host, or -1 if the connection was lost.
2573
2574 Argument: none
2575
2576 Returns: > 0 message successfully started (reached DATA)
2577 = 0 QUIT read or end of file reached or call refused
2578 < 0 lost connection
2579 */
2580
2581 int
2582 smtp_setup_msg(void)
2583 {
2584 int done = 0;
2585 BOOL toomany = FALSE;
2586 BOOL discarded = FALSE;
2587 BOOL last_was_rej_mail = FALSE;
2588 BOOL last_was_rcpt = FALSE;
2589 void *reset_point = store_get(0);
2590
2591 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2592
2593 /* Reset for start of new message. We allow one RSET not to be counted as a
2594 nonmail command, for those MTAs that insist on sending it between every
2595 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2596 TLS between messages (an Exim client may do this if it has messages queued up
2597 for the host). Note: we do NOT reset AUTH at this point. */
2598
2599 smtp_reset(reset_point);
2600 message_ended = END_NOTSTARTED;
2601
2602 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2603 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2604 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2605 #ifdef SUPPORT_TLS
2606 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2607 #endif
2608
2609 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2610
2611 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2612
2613 /* Batched SMTP is handled in a different function. */
2614
2615 if (smtp_batched_input) return smtp_setup_batch_msg();
2616
2617 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2618 value. The values are 2 larger than the required yield of the function. */
2619
2620 while (done <= 0)
2621 {
2622 uschar **argv;
2623 uschar *etrn_command;
2624 uschar *etrn_serialize_key;
2625 uschar *errmess;
2626 uschar *log_msg, *smtp_code;
2627 uschar *user_msg = NULL;
2628 uschar *recipient = NULL;
2629 uschar *hello = NULL;
2630 uschar *set_id = NULL;
2631 uschar *s, *ss;
2632 BOOL was_rej_mail = FALSE;
2633 BOOL was_rcpt = FALSE;
2634 void (*oldsignal)(int);
2635 pid_t pid;
2636 int start, end, sender_domain, recipient_domain;
2637 int ptr, size, rc;
2638 int c, i;
2639 auth_instance *au;
2640
2641 switch(smtp_read_command(TRUE))
2642 {
2643 /* The AUTH command is not permitted to occur inside a transaction, and may
2644 occur successfully only once per connection. Actually, that isn't quite
2645 true. When TLS is started, all previous information about a connection must
2646 be discarded, so a new AUTH is permitted at that time.
2647
2648 AUTH may only be used when it has been advertised. However, it seems that
2649 there are clients that send AUTH when it hasn't been advertised, some of
2650 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2651 So there's a get-out that allows this to happen.
2652
2653 AUTH is initially labelled as a "nonmail command" so that one occurrence
2654 doesn't get counted. We change the label here so that multiple failing
2655 AUTHS will eventually hit the nonmail threshold. */
2656
2657 case AUTH_CMD:
2658 HAD(SCH_AUTH);
2659 authentication_failed = TRUE;
2660 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2661
2662 if (!auth_advertised && !allow_auth_unadvertised)
2663 {
2664 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2665 US"AUTH command used when not advertised");
2666 break;
2667 }
2668 if (sender_host_authenticated != NULL)
2669 {
2670 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2671 US"already authenticated");
2672 break;
2673 }
2674 if (sender_address != NULL)
2675 {
2676 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2677 US"not permitted in mail transaction");
2678 break;
2679 }
2680
2681 /* Check the ACL */
2682
2683 if (acl_smtp_auth != NULL)
2684 {
2685 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2686 if (rc != OK)
2687 {
2688 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2689 break;
2690 }
2691 }
2692
2693 /* Find the name of the requested authentication mechanism. */
2694
2695 s = smtp_cmd_data;
2696 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
2697 {
2698 if (!isalnum(c) && c != '-' && c != '_')
2699 {
2700 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2701 US"invalid character in authentication mechanism name");
2702 goto COMMAND_LOOP;
2703 }
2704 smtp_cmd_data++;
2705 }
2706
2707 /* If not at the end of the line, we must be at white space. Terminate the
2708 name and move the pointer on to any data that may be present. */
2709
2710 if (*smtp_cmd_data != 0)
2711 {
2712 *smtp_cmd_data++ = 0;
2713 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
2714 }
2715
2716 /* Search for an authentication mechanism which is configured for use
2717 as a server and which has been advertised (unless, sigh, allow_auth_
2718 unadvertised is set). */
2719
2720 for (au = auths; au != NULL; au = au->next)
2721 {
2722 if (strcmpic(s, au->public_name) == 0 && au->server &&
2723 (au->advertised || allow_auth_unadvertised)) break;
2724 }
2725
2726 if (au == NULL)
2727 {
2728 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2729 string_sprintf("%s authentication mechanism not supported", s));
2730 break;
2731 }
2732
2733 /* Run the checking code, passing the remainder of the command line as
2734 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2735 it as the only set numerical variable. The authenticator may set $auth<n>
2736 and also set other numeric variables. The $auth<n> variables are preferred
2737 nowadays; the numerical variables remain for backwards compatibility.
2738
2739 Afterwards, have a go at expanding the set_id string, even if
2740 authentication failed - for bad passwords it can be useful to log the
2741 userid. On success, require set_id to expand and exist, and put it in
2742 authenticated_id. Save this in permanent store, as the working store gets
2743 reset at HELO, RSET, etc. */
2744
2745 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2746 expand_nmax = 0;
2747 expand_nlength[0] = 0; /* $0 contains nothing */
2748
2749 c = (au->info->servercode)(au, smtp_cmd_data);
2750 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2751 expand_nmax = -1; /* Reset numeric variables */
2752 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2753
2754 /* The value of authenticated_id is stored in the spool file and printed in
2755 log lines. It must not contain binary zeros or newline characters. In
2756 normal use, it never will, but when playing around or testing, this error
2757 can (did) happen. To guard against this, ensure that the id contains only
2758 printing characters. */
2759
2760 if (set_id != NULL) set_id = string_printing(set_id);
2761
2762 /* For the non-OK cases, set up additional logging data if set_id
2763 is not empty. */
2764
2765 if (c != OK)
2766 {
2767 if (set_id != NULL && *set_id != 0)
2768 set_id = string_sprintf(" (set_id=%s)", set_id);
2769 else set_id = US"";
2770 }
2771
2772 /* Switch on the result */
2773
2774 switch(c)
2775 {
2776 case OK:
2777 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2778 {
2779 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2780 sender_host_authenticated = au->name;
2781 authentication_failed = FALSE;
2782 received_protocol =
2783 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2784 ((sender_host_address != NULL)? pnlocal : 0);
2785 s = ss = US"235 Authentication succeeded";
2786 authenticated_by = au;
2787 break;
2788 }
2789
2790 /* Authentication succeeded, but we failed to expand the set_id string.
2791 Treat this as a temporary error. */
2792
2793 auth_defer_msg = expand_string_message;
2794 /* Fall through */
2795
2796 case DEFER:
2797 s = string_sprintf("435 Unable to authenticate at present%s",
2798 auth_defer_user_msg);
2799 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2800 set_id, auth_defer_msg);
2801 break;
2802
2803 case BAD64:
2804 s = ss = US"501 Invalid base64 data";
2805 break;
2806
2807 case CANCELLED:
2808 s = ss = US"501 Authentication cancelled";
2809 break;
2810
2811 case UNEXPECTED:
2812 s = ss = US"553 Initial data not expected";
2813 break;
2814
2815 case FAIL:
2816 s = US"535 Incorrect authentication data";
2817 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2818 break;
2819
2820 default:
2821 s = US"435 Internal error";
2822 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2823 "check", set_id, c);
2824 break;
2825 }
2826
2827 smtp_printf("%s\r\n", s);
2828 if (c != OK)
2829 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2830 au->name, host_and_ident(FALSE), ss);
2831
2832 break; /* AUTH_CMD */
2833
2834 /* The HELO/EHLO commands are permitted to appear in the middle of a
2835 session as well as at the beginning. They have the effect of a reset in
2836 addition to their other functions. Their absence at the start cannot be
2837 taken to be an error.
2838
2839 RFC 2821 says:
2840
2841 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2842 or 502 failure replies MUST be returned as appropriate. The SMTP
2843 server MUST stay in the same state after transmitting these replies
2844 that it was in before the EHLO was received.
2845
2846 Therefore, we do not do the reset until after checking the command for
2847 acceptability. This change was made for Exim release 4.11. Previously
2848 it did the reset first. */
2849
2850 case HELO_CMD:
2851 HAD(SCH_HELO);
2852 hello = US"HELO";
2853 esmtp = FALSE;
2854 goto HELO_EHLO;
2855
2856 case EHLO_CMD:
2857 HAD(SCH_EHLO);
2858 hello = US"EHLO";
2859 esmtp = TRUE;
2860
2861 HELO_EHLO: /* Common code for HELO and EHLO */
2862 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2863 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2864
2865 /* Reject the HELO if its argument was invalid or non-existent. A
2866 successful check causes the argument to be saved in malloc store. */
2867
2868 if (!check_helo(smtp_cmd_data))
2869 {
2870 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2871
2872 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2873 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2874 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2875 string_printing(smtp_cmd_argument));
2876
2877 if (++synprot_error_count > smtp_max_synprot_errors)
2878 {
2879 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2880 "syntax or protocol errors (last command was \"%s\")",
2881 host_and_ident(FALSE), smtp_cmd_buffer);
2882 done = 1;
2883 }
2884
2885 break;
2886 }
2887
2888 /* If sender_host_unknown is true, we have got here via the -bs interface,
2889 not called from inetd. Otherwise, we are running an IP connection and the
2890 host address will be set. If the helo name is the primary name of this
2891 host and we haven't done a reverse lookup, force one now. If helo_required
2892 is set, ensure that the HELO name matches the actual host. If helo_verify
2893 is set, do the same check, but softly. */
2894
2895 if (!sender_host_unknown)
2896 {
2897 BOOL old_helo_verified = helo_verified;
2898 uschar *p = smtp_cmd_data;
2899
2900 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2901 *p = 0;
2902
2903 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2904 because otherwise the log can be confusing. */
2905
2906 if (sender_host_name == NULL &&
2907 (deliver_domain = sender_helo_name, /* set $domain */
2908 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2909 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2910 (void)host_name_lookup();
2911
2912 /* Rebuild the fullhost info to include the HELO name (and the real name
2913 if it was looked up.) */
2914
2915 host_build_sender_fullhost(); /* Rebuild */
2916 set_process_info("handling%s incoming connection from %s",
2917 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2918
2919 /* Verify if configured. This doesn't give much security, but it does
2920 make some people happy to be able to do it. If helo_required is set,
2921 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2922 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2923 now obsolescent, since the verification can now be requested selectively
2924 at ACL time. */
2925
2926 helo_verified = helo_verify_failed = FALSE;
2927 if (helo_required || helo_verify)
2928 {
2929 BOOL tempfail = !smtp_verify_helo();
2930 if (!helo_verified)
2931 {
2932 if (helo_required)
2933 {
2934 smtp_printf("%d %s argument does not match calling host\r\n",
2935 tempfail? 451 : 550, hello);
2936 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2937 tempfail? "temporarily " : "",
2938 hello, sender_helo_name, host_and_ident(FALSE));
2939 helo_verified = old_helo_verified;
2940 break; /* End of HELO/EHLO processing */
2941 }
2942 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2943 "helo_try_verify_hosts\n", hello);
2944 }
2945 }
2946 }
2947
2948 #ifdef EXPERIMENTAL_SPF
2949 /* set up SPF context */
2950 spf_init(sender_helo_name, sender_host_address);
2951 #endif
2952
2953 /* Apply an ACL check if one is defined; afterwards, recheck
2954 synchronization in case the client started sending in a delay. */
2955
2956 if (acl_smtp_helo != NULL)
2957 {
2958 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2959 if (rc != OK)
2960 {
2961 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2962 sender_helo_name = NULL;
2963 host_build_sender_fullhost(); /* Rebuild */
2964 break;
2965 }
2966 else if (!check_sync()) goto SYNC_FAILURE;
2967 }
2968
2969 /* Generate an OK reply. The default string includes the ident if present,
2970 and also the IP address if present. Reflecting back the ident is intended
2971 as a deterrent to mail forgers. For maximum efficiency, and also because
2972 some broken systems expect each response to be in a single packet, arrange
2973 that the entire reply is sent in one write(). */
2974
2975 auth_advertised = FALSE;
2976 pipelining_advertised = FALSE;
2977 #ifdef SUPPORT_TLS
2978 tls_advertised = FALSE;
2979 #endif
2980
2981 smtp_code = US"250 "; /* Default response code plus space*/
2982 if (user_msg == NULL)
2983 {
2984 s = string_sprintf("%.3s %s Hello %s%s%s",
2985 smtp_code,
2986 smtp_active_hostname,
2987 (sender_ident == NULL)? US"" : sender_ident,
2988 (sender_ident == NULL)? US"" : US" at ",
2989 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2990
2991 ptr = Ustrlen(s);
2992 size = ptr + 1;
2993
2994 if (sender_host_address != NULL)
2995 {
2996 s = string_cat(s, &size, &ptr, US" [", 2);
2997 s = string_cat(s, &size, &ptr, sender_host_address,
2998 Ustrlen(sender_host_address));
2999 s = string_cat(s, &size, &ptr, US"]", 1);
3000 }
3001 }
3002
3003 /* A user-supplied EHLO greeting may not contain more than one line. Note
3004 that the code returned by smtp_message_code() includes the terminating
3005 whitespace character. */
3006
3007 else
3008 {
3009 char *ss;
3010 int codelen = 4;
3011 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3012 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3013 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3014 {
3015 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3016 "newlines: message truncated: %s", string_printing(s));
3017 *ss = 0;
3018 }
3019 ptr = Ustrlen(s);
3020 size = ptr + 1;
3021 }
3022
3023 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3024
3025 /* If we received EHLO, we must create a multiline response which includes
3026 the functions supported. */
3027
3028 if (esmtp)
3029 {
3030 s[3] = '-';
3031
3032 /* I'm not entirely happy with this, as an MTA is supposed to check
3033 that it has enough room to accept a message of maximum size before
3034 it sends this. However, there seems little point in not sending it.
3035 The actual size check happens later at MAIL FROM time. By postponing it
3036 till then, VRFY and EXPN can be used after EHLO when space is short. */
3037
3038 if (thismessage_size_limit > 0)
3039 {
3040 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3041 thismessage_size_limit);
3042 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3043 }
3044 else
3045 {
3046 s = string_cat(s, &size, &ptr, smtp_code, 3);
3047 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3048 }
3049
3050 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3051 clean; if it has an 8-bit character in its hand, it just sends it. It
3052 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3053 However, some users want this option simply in order to stop MUAs
3054 mangling messages that contain top-bit-set characters. It is therefore
3055 provided as an option. */
3056
3057 if (accept_8bitmime)
3058 {
3059 s = string_cat(s, &size, &ptr, smtp_code, 3);
3060 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3061 }
3062
3063 /* Advertise ETRN if there's an ACL checking whether a host is
3064 permitted to issue it; a check is made when any host actually tries. */
3065
3066 if (acl_smtp_etrn != NULL)
3067 {
3068 s = string_cat(s, &size, &ptr, smtp_code, 3);
3069 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3070 }
3071
3072 /* Advertise EXPN if there's an ACL checking whether a host is
3073 permitted to issue it; a check is made when any host actually tries. */
3074
3075 if (acl_smtp_expn != NULL)
3076 {
3077 s = string_cat(s, &size, &ptr, smtp_code, 3);
3078 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3079 }
3080
3081 /* Exim is quite happy with pipelining, so let the other end know that
3082 it is safe to use it, unless advertising is disabled. */
3083
3084 if (pipelining_enable &&
3085 verify_check_host(&pipelining_advertise_hosts) == OK)
3086 {
3087 s = string_cat(s, &size, &ptr, smtp_code, 3);
3088 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3089 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3090 pipelining_advertised = TRUE;
3091 }
3092
3093 /* If any server authentication mechanisms are configured, advertise
3094 them if the current host is in auth_advertise_hosts. The problem with
3095 advertising always is that some clients then require users to
3096 authenticate (and aren't configurable otherwise) even though it may not
3097 be necessary (e.g. if the host is in host_accept_relay).
3098
3099 RFC 2222 states that SASL mechanism names contain only upper case
3100 letters, so output the names in upper case, though we actually recognize
3101 them in either case in the AUTH command. */
3102
3103 if (auths != NULL)
3104 {
3105 if (verify_check_host(&auth_advertise_hosts) == OK)
3106 {
3107 auth_instance *au;
3108 BOOL first = TRUE;
3109 for (au = auths; au != NULL; au = au->next)
3110 {
3111 if (au->server && (au->advertise_condition == NULL ||
3112 expand_check_condition(au->advertise_condition, au->name,
3113 US"authenticator")))
3114 {
3115 int saveptr;
3116 if (first)
3117 {
3118 s = string_cat(s, &size, &ptr, smtp_code, 3);
3119 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3120 first = FALSE;
3121 auth_advertised = TRUE;
3122 }
3123 saveptr = ptr;
3124 s = string_cat(s, &size, &ptr, US" ", 1);
3125 s = string_cat(s, &size, &ptr, au->public_name,
3126 Ustrlen(au->public_name));
3127 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3128 au->advertised = TRUE;
3129 }
3130 else au->advertised = FALSE;
3131 }
3132 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3133 }
3134 }
3135
3136 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3137 if it has been included in the binary, and the host matches
3138 tls_advertise_hosts. We must *not* advertise if we are already in a
3139 secure connection. */
3140
3141 #ifdef SUPPORT_TLS
3142 if (tls_active < 0 &&
3143 verify_check_host(&tls_advertise_hosts) != FAIL)
3144 {
3145 s = string_cat(s, &size, &ptr, smtp_code, 3);
3146 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3147 tls_advertised = TRUE;
3148 }
3149 #endif
3150
3151 /* Finish off the multiline reply with one that is always available. */
3152
3153 s = string_cat(s, &size, &ptr, smtp_code, 3);
3154 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3155 }
3156
3157 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3158 has been seen. */
3159
3160 s[ptr] = 0;
3161
3162 #ifdef SUPPORT_TLS
3163 if (tls_active >= 0) (void)tls_write(s, ptr); else
3164 #endif
3165
3166 (void)fwrite(s, 1, ptr, smtp_out);
3167 DEBUG(D_receive)
3168 {
3169 uschar *cr;
3170 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3171 memmove(cr, cr + 1, (ptr--) - (cr - s));
3172 debug_printf("SMTP>> %s", s);
3173 }
3174 helo_seen = TRUE;
3175
3176 /* Reset the protocol and the state, abandoning any previous message. */
3177
3178 received_protocol = (esmtp?
3179 protocols[pextend +
3180 ((sender_host_authenticated != NULL)? pauthed : 0) +
3181 ((tls_active >= 0)? pcrpted : 0)]
3182 :
3183 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
3184 +
3185 ((sender_host_address != NULL)? pnlocal : 0);
3186
3187 smtp_reset(reset_point);
3188 toomany = FALSE;
3189 break; /* HELO/EHLO */
3190
3191
3192 /* The MAIL command requires an address as an operand. All we do
3193 here is to parse it for syntactic correctness. The form "<>" is
3194 a special case which converts into an empty string. The start/end
3195 pointers in the original are not used further for this address, as
3196 it is the canonical extracted address which is all that is kept. */
3197
3198 case MAIL_CMD:
3199 HAD(SCH_MAIL);
3200 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3201 was_rej_mail = TRUE; /* Reset if accepted */
3202
3203 if (helo_required && !helo_seen)
3204 {
3205 smtp_printf("503 HELO or EHLO required\r\n");
3206 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3207 "HELO/EHLO given", host_and_ident(FALSE));
3208 break;
3209 }
3210
3211 if (sender_address != NULL)
3212 {
3213 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3214 US"sender already given");
3215 break;
3216 }
3217
3218 if (smtp_cmd_data[0] == 0)
3219 {
3220 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3221 US"MAIL must have an address operand");
3222 break;
3223 }
3224
3225 /* Check to see if the limit for messages per connection would be
3226 exceeded by accepting further messages. */
3227
3228 if (smtp_accept_max_per_connection > 0 &&
3229 smtp_mailcmd_count > smtp_accept_max_per_connection)
3230 {
3231 smtp_printf("421 too many messages in this connection\r\n");
3232 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3233 "messages in one connection", host_and_ident(TRUE));
3234 break;
3235 }
3236
3237 /* Reset for start of message - even if this is going to fail, we
3238 obviously need to throw away any previous data. */
3239
3240 smtp_reset(reset_point);
3241 toomany = FALSE;
3242 sender_data = recipient_data = NULL;
3243
3244 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3245
3246 if (esmtp) for(;;)
3247 {
3248 uschar *name, *value, *end;
3249 unsigned long int size;
3250
3251 if (!extract_option(&name, &value)) break;
3252
3253 /* Handle SIZE= by reading the value. We don't do the check till later,
3254 in order to be able to log the sender address on failure. */
3255
3256 if (strcmpic(name, US"SIZE") == 0 &&
3257 ((size = Ustrtoul(value, &end, 10)), *end == 0))
3258 {
3259 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3260 size = INT_MAX;
3261 message_size = (int)size;
3262 }
3263
3264 /* If this session was initiated with EHLO and accept_8bitmime is set,
3265 Exim will have indicated that it supports the BODY=8BITMIME option. In
3266 fact, it does not support this according to the RFCs, in that it does not
3267 take any special action for forwarding messages containing 8-bit
3268 characters. That is why accept_8bitmime is not the default setting, but
3269 some sites want the action that is provided. We recognize both "8BITMIME"
3270 and "7BIT" as body types, but take no action. */
3271
3272 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
3273 (strcmpic(value, US"8BITMIME") == 0 ||
3274 strcmpic(value, US"7BIT") == 0)) {}
3275
3276 /* Handle the AUTH extension. If the value given is not "<>" and either
3277 the ACL says "yes" or there is no ACL but the sending host is
3278 authenticated, we set it up as the authenticated sender. However, if the
3279 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3280 the condition is met. The value of AUTH is an xtext, which means that +,
3281 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3282 coding. */
3283
3284 else if (strcmpic(name, US"AUTH") == 0)
3285 {
3286 if (Ustrcmp(value, "<>") != 0)
3287 {
3288 int rc;
3289 uschar *ignore_msg;
3290
3291 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3292 {
3293 /* Put back terminator overrides for error message */
3294 name[-1] = ' ';
3295 value[-1] = '=';
3296 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3297 US"invalid data for AUTH");
3298 goto COMMAND_LOOP;
3299 }
3300
3301 if (acl_smtp_mailauth == NULL)
3302 {
3303 ignore_msg = US"client not authenticated";
3304 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3305 }
3306 else
3307 {
3308 ignore_msg = US"rejected by ACL";
3309 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3310 &user_msg, &log_msg);
3311 }
3312
3313 switch (rc)
3314 {
3315 case OK:
3316 if (authenticated_by == NULL ||
3317 authenticated_by->mail_auth_condition == NULL ||
3318 expand_check_condition(authenticated_by->mail_auth_condition,
3319 authenticated_by->name, US"authenticator"))
3320 break; /* Accept the AUTH */
3321
3322 ignore_msg = US"server_mail_auth_condition failed";
3323 if (authenticated_id != NULL)
3324 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3325 ignore_msg, authenticated_id);
3326
3327 /* Fall through */
3328
3329 case FAIL:
3330 authenticated_sender = NULL;
3331 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3332 value, host_and_ident(TRUE), ignore_msg);
3333 break;
3334
3335 /* Should only get DEFER or ERROR here. Put back terminator
3336 overrides for error message */
3337
3338 default:
3339 name[-1] = ' ';
3340 value[-1] = '=';
3341 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3342 log_msg);
3343 goto COMMAND_LOOP;
3344 }
3345 }
3346 }
3347
3348 /* Unknown option. Stick back the terminator characters and break
3349 the loop. An error for a malformed address will occur. */
3350
3351 else
3352 {
3353 name[-1] = ' ';
3354 value[-1] = '=';
3355 break;
3356 }
3357 }
3358
3359 /* If we have passed the threshold for rate limiting, apply the current
3360 delay, and update it for next time, provided this is a limited host. */
3361
3362 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3363 verify_check_host(&smtp_ratelimit_hosts) == OK)
3364 {
3365 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3366 smtp_delay_mail/1000.0);
3367 millisleep((int)smtp_delay_mail);
3368 smtp_delay_mail *= smtp_rlm_factor;
3369 if (smtp_delay_mail > (double)smtp_rlm_limit)
3370 smtp_delay_mail = (double)smtp_rlm_limit;
3371 }
3372
3373 /* Now extract the address, first applying any SMTP-time rewriting. The
3374 TRUE flag allows "<>" as a sender address. */
3375
3376 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3377 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3378 global_rewrite_rules) : smtp_cmd_data;
3379
3380 /* rfc821_domains = TRUE; << no longer needed */
3381 raw_sender =
3382 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3383 TRUE);
3384 /* rfc821_domains = FALSE; << no longer needed */
3385
3386 if (raw_sender == NULL)
3387 {
3388 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3389 break;
3390 }
3391
3392 sender_address = raw_sender;
3393
3394 /* If there is a configured size limit for mail, check that this message
3395 doesn't exceed it. The check is postponed to this point so that the sender
3396 can be logged. */
3397
3398 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3399 {
3400 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3401 log_write(L_size_reject,
3402 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3403 "message too big: size%s=%d max=%d",
3404 sender_address,
3405 host_and_ident(TRUE),
3406 (message_size == INT_MAX)? ">" : "",
3407 message_size,
3408 thismessage_size_limit);
3409 sender_address = NULL;
3410 break;
3411 }
3412
3413 /* Check there is enough space on the disk unless configured not to.
3414 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3415 plus the current message - i.e. we accept the message only if it won't
3416 reduce the space below the threshold. Add 5000 to the size to allow for
3417 overheads such as the Received: line and storing of recipients, etc.
3418 By putting the check here, even when SIZE is not given, it allow VRFY
3419 and EXPN etc. to be used when space is short. */
3420
3421 if (!receive_check_fs(
3422 (smtp_check_spool_space && message_size >= 0)?
3423 message_size + 5000 : 0))
3424 {
3425 smtp_printf("452 Space shortage, please try later\r\n");
3426 sender_address = NULL;
3427 break;
3428 }
3429
3430 /* If sender_address is unqualified, reject it, unless this is a locally
3431 generated message, or the sending host or net is permitted to send
3432 unqualified addresses - typically local machines behaving as MUAs -
3433 in which case just qualify the address. The flag is set above at the start
3434 of the SMTP connection. */
3435
3436 if (sender_domain == 0 && sender_address[0] != 0)
3437 {
3438 if (allow_unqualified_sender)
3439 {
3440 sender_domain = Ustrlen(sender_address) + 1;
3441 sender_address = rewrite_address_qualify(sender_address, FALSE);
3442 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3443 raw_sender);
3444 }
3445 else
3446 {
3447 smtp_printf("501 %s: sender address must contain a domain\r\n",
3448 smtp_cmd_data);
3449 log_write(L_smtp_syntax_error,
3450 LOG_MAIN|LOG_REJECT,
3451 "unqualified sender rejected: <%s> %s%s",
3452 raw_sender,
3453 host_and_ident(TRUE),
3454 host_lookup_msg);
3455 sender_address = NULL;
3456 break;
3457 }
3458 }
3459
3460 /* Apply an ACL check if one is defined, before responding. Afterwards,
3461 when pipelining is not advertised, do another sync check in case the ACL
3462 delayed and the client started sending in the meantime. */
3463
3464 if (acl_smtp_mail == NULL) rc = OK; else
3465 {
3466 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3467 if (rc == OK && !pipelining_advertised && !check_sync())
3468 goto SYNC_FAILURE;
3469 }
3470
3471 if (rc == OK || rc == DISCARD)
3472 {
3473 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3474 else smtp_user_msg(US"250", user_msg);
3475 smtp_delay_rcpt = smtp_rlr_base;
3476 recipients_discarded = (rc == DISCARD);
3477 was_rej_mail = FALSE;
3478 }
3479 else
3480 {
3481 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3482 sender_address = NULL;
3483 }
3484 break;
3485
3486
3487 /* The RCPT command requires an address as an operand. There may be any
3488 number of RCPT commands, specifying multiple recipients. We build them all
3489 into a data structure. The start/end values given by parse_extract_address
3490 are not used, as we keep only the extracted address. */
3491
3492 case RCPT_CMD:
3493 HAD(SCH_RCPT);
3494 rcpt_count++;
3495 was_rcpt = rcpt_in_progress = TRUE;
3496
3497 /* There must be a sender address; if the sender was rejected and
3498 pipelining was advertised, we assume the client was pipelining, and do not
3499 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3500 get the same treatment. */
3501
3502 if (sender_address == NULL)
3503 {
3504 if (pipelining_advertised && last_was_rej_mail)
3505 {
3506 smtp_printf("503 sender not yet given\r\n");
3507 was_rej_mail = TRUE;