f534d1ca7809c9e18f5cf2993b249548610396e5
[exim.git] / src / src / smtp_in.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2016 */
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 #include <assert.h>
13
14
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
18
19 #ifdef USE_TCP_WRAPPERS
20
21 #if HAVE_IPV6
22 #define EXIM_HAVE_IPV6
23 #endif
24 #undef HAVE_IPV6
25 #include <tcpd.h>
26 #undef HAVE_IPV6
27 #ifdef EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
29 #endif
30
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
34 #endif
35
36
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
45 */
46
47 #define smtp_cmd_buffer_size 16384
48
49 /* Size of buffer for reading SMTP incoming packets */
50
51 #define in_buffer_size 8192
52
53 /* Structure for SMTP command list */
54
55 typedef struct {
56 const char *name;
57 int len;
58 short int cmd;
59 short int has_arg;
60 short int is_mail_cmd;
61 } smtp_cmd_list;
62
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
65 block some spam. */
66
67 enum {
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
70
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
76
77 /* This is a dummy to identify the non-sync commands when pipelining */
78
79 NON_SYNC_CMD_PIPELINING,
80
81 /* These commands need not be synchronized when pipelining */
82
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
84
85 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
86 processed the message is sent using a series of BDAT commands"
87 implies that BDAT should be synchronized. However, we see Google, at least,
88 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
89 processing of the RPCT response(s). We shall do the same, and not require
90 synch for BDAT. */
91
92 BDAT_CMD,
93
94 /* This is a dummy to identify the non-sync commands when not pipelining */
95
96 NON_SYNC_CMD_NON_PIPELINING,
97
98 /* I have been unable to find a statement about the use of pipelining
99 with AUTH, so to be on the safe side it is here, though I kind of feel
100 it should be up there with the synchronized commands. */
101
102 AUTH_CMD,
103
104 /* I'm not sure about these, but I don't think they matter. */
105
106 QUIT_CMD, HELP_CMD,
107
108 #ifdef SUPPORT_PROXY
109 PROXY_FAIL_IGNORE_CMD,
110 #endif
111
112 /* These are specials that don't correspond to actual commands */
113
114 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
115 TOO_MANY_NONMAIL_CMD };
116
117
118 /* This is a convenience macro for adding the identity of an SMTP command
119 to the circular buffer that holds a list of the last n received. */
120
121 #define HAD(n) \
122 smtp_connection_had[smtp_ch_index++] = n; \
123 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
124
125
126 /*************************************************
127 * Local static variables *
128 *************************************************/
129
130 static auth_instance *authenticated_by;
131 static BOOL auth_advertised;
132 #ifdef SUPPORT_TLS
133 static BOOL tls_advertised;
134 #endif
135 static BOOL dsn_advertised;
136 static BOOL esmtp;
137 static BOOL helo_required = FALSE;
138 static BOOL helo_verify = FALSE;
139 static BOOL helo_seen;
140 static BOOL helo_accept_junk;
141 static BOOL count_nonmail;
142 static BOOL pipelining_advertised;
143 static BOOL rcpt_smtp_response_same;
144 static BOOL rcpt_in_progress;
145 static int nonmail_command_count;
146 static BOOL smtp_exit_function_called = 0;
147 #ifdef SUPPORT_I18N
148 static BOOL smtputf8_advertised;
149 #endif
150 static int synprot_error_count;
151 static int unknown_command_count;
152 static int sync_cmd_limit;
153 static int smtp_write_error = 0;
154
155 static uschar *rcpt_smtp_response;
156 static uschar *smtp_data_buffer;
157 static uschar *smtp_cmd_data;
158
159 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
160 final fields of all except AUTH are forced TRUE at the start of a new message
161 setup, to allow one of each between messages that is not counted as a nonmail
162 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
163 allow a new EHLO after starting up TLS.
164
165 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
166 counted. However, the flag is changed when AUTH is received, so that multiple
167 failing AUTHs will eventually hit the limit. After a successful AUTH, another
168 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
169 forced TRUE, to allow for the re-authentication that can happen at that point.
170
171 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
172 count of non-mail commands and possibly provoke an error.
173
174 tls_auth is a pseudo-command, never expected in input. It is activated
175 on TLS startup and looks for a tls authenticator. */
176
177 static smtp_cmd_list cmd_list[] = {
178 /* name len cmd has_arg is_mail_cmd */
179
180 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
181 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
182 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
183 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
184 #ifdef SUPPORT_TLS
185 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
186 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, TRUE },
187 #endif
188
189 /* If you change anything above here, also fix the definitions below. */
190
191 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
192 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
193 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
194 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
195 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
196 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
197 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
198 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
199 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
200 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
201 };
202
203 static smtp_cmd_list *cmd_list_end =
204 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
205
206 #define CMD_LIST_RSET 0
207 #define CMD_LIST_HELO 1
208 #define CMD_LIST_EHLO 2
209 #define CMD_LIST_AUTH 3
210 #define CMD_LIST_STARTTLS 4
211 #define CMD_LIST_TLS_AUTH 5
212
213 /* This list of names is used for performing the smtp_no_mail logging action.
214 It must be kept in step with the SCH_xxx enumerations. */
215
216 static uschar *smtp_names[] =
217 {
218 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
219 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
220 US"STARTTLS", US"VRFY" };
221
222 static uschar *protocols_local[] = {
223 US"local-smtp", /* HELO */
224 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
225 US"local-esmtp", /* EHLO */
226 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
227 US"local-esmtpa", /* EHLO->AUTH */
228 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
229 };
230 static uschar *protocols[] = {
231 US"smtp", /* HELO */
232 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
233 US"esmtp", /* EHLO */
234 US"esmtps", /* EHLO->STARTTLS->EHLO */
235 US"esmtpa", /* EHLO->AUTH */
236 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
237 };
238
239 #define pnormal 0
240 #define pextend 2
241 #define pcrpted 1 /* added to pextend or pnormal */
242 #define pauthed 2 /* added to pextend */
243
244 /* Sanity check and validate optional args to MAIL FROM: envelope */
245 enum {
246 ENV_MAIL_OPT_NULL,
247 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
248 #ifndef DISABLE_PRDR
249 ENV_MAIL_OPT_PRDR,
250 #endif
251 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
252 #ifdef SUPPORT_I18N
253 ENV_MAIL_OPT_UTF8,
254 #endif
255 };
256 typedef struct {
257 uschar * name; /* option requested during MAIL cmd */
258 int value; /* enum type */
259 BOOL need_value; /* TRUE requires value (name=value pair format)
260 FALSE is a singleton */
261 } env_mail_type_t;
262 static env_mail_type_t env_mail_type_list[] = {
263 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
264 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
265 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
266 #ifndef DISABLE_PRDR
267 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
268 #endif
269 { US"RET", ENV_MAIL_OPT_RET, TRUE },
270 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
271 #ifdef SUPPORT_I18N
272 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
273 #endif
274 /* keep this the last entry */
275 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
276 };
277
278 /* When reading SMTP from a remote host, we have to use our own versions of the
279 C input-reading functions, in order to be able to flush the SMTP output only
280 when about to read more data from the socket. This is the only way to get
281 optimal performance when the client is using pipelining. Flushing for every
282 command causes a separate packet and reply packet each time; saving all the
283 responses up (when pipelining) combines them into one packet and one response.
284
285 For simplicity, these functions are used for *all* SMTP input, not only when
286 receiving over a socket. However, after setting up a secure socket (SSL), input
287 is read via the OpenSSL library, and another set of functions is used instead
288 (see tls.c).
289
290 These functions are set in the receive_getc etc. variables and called with the
291 same interface as the C functions. However, since there can only ever be
292 one incoming SMTP call, we just use a single buffer and flags. There is no need
293 to implement a complicated private FILE-like structure.*/
294
295 static uschar *smtp_inbuffer;
296 static uschar *smtp_inptr;
297 static uschar *smtp_inend;
298 static int smtp_had_eof;
299 static int smtp_had_error;
300
301
302 /* forward declarations */
303 int bdat_ungetc(int ch);
304 static int smtp_read_command(BOOL check_sync);
305 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
306 static void smtp_quit_handler(uschar **, uschar **);
307 static void smtp_rset_handler(void);
308
309 /*************************************************
310 * SMTP version of getc() *
311 *************************************************/
312
313 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
314 it flushes the output, and refills the buffer, with a timeout. The signal
315 handler is set appropriately by the calling function. This function is not used
316 after a connection has negotated itself into an TLS/SSL state.
317
318 Arguments: none
319 Returns: the next character or EOF
320 */
321
322 int
323 smtp_getc(void)
324 {
325 if (smtp_inptr >= smtp_inend)
326 {
327 int rc, save_errno;
328 if (!smtp_out) return EOF;
329 fflush(smtp_out);
330 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
331 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
332 save_errno = errno;
333 alarm(0);
334 if (rc <= 0)
335 {
336 /* Must put the error text in fixed store, because this might be during
337 header reading, where it releases unused store above the header. */
338 if (rc < 0)
339 {
340 smtp_had_error = save_errno;
341 smtp_read_error = string_copy_malloc(
342 string_sprintf(" (error: %s)", strerror(save_errno)));
343 }
344 else smtp_had_eof = 1;
345 return EOF;
346 }
347 #ifndef DISABLE_DKIM
348 dkim_exim_verify_feed(smtp_inbuffer, rc);
349 #endif
350 smtp_inend = smtp_inbuffer + rc;
351 smtp_inptr = smtp_inbuffer;
352 }
353 return *smtp_inptr++;
354 }
355
356 void
357 smtp_get_cache(void)
358 {
359 #ifndef DISABLE_DKIM
360 int n = smtp_inend - smtp_inptr;
361 if (n > 0)
362 dkim_exim_verify_feed(smtp_inptr, n);
363 #endif
364 }
365
366
367 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
368 previous BDAT chunk and getting new ones when we run out. Uses the
369 underlying smtp_getc or tls_getc both for that and for getting the
370 (buffered) data byte. EOD signals (an expected) no further data.
371 ERR signals a protocol error, and EOF a closed input stream.
372
373 Called from read_bdat_smtp() in receive.c for the message body, but also
374 by the headers read loop in receive_msg(); manipulates chunking_state
375 to handle the BDAT command/response.
376 Placed here due to the correlation with the above smtp_getc(), which it wraps,
377 and also by the need to do smtp command/response handling.
378
379 Arguments: none
380 Returns: the next character or ERR, EOD or EOF
381 */
382
383 int
384 bdat_getc(void)
385 {
386 uschar * user_msg = NULL;
387 uschar * log_msg;
388
389 for(;;)
390 {
391 if (chunking_data_left-- > 0)
392 return lwr_receive_getc();
393
394 receive_getc = lwr_receive_getc;
395 receive_ungetc = lwr_receive_ungetc;
396
397 /* If not the last, ack the received chunk. The last response is delayed
398 until after the data ACL decides on it */
399
400 if (chunking_state == CHUNKING_LAST)
401 {
402 #ifndef DISABLE_DKIM
403 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
404 #endif
405 return EOD;
406 }
407
408 chunking_state = CHUNKING_OFFERED;
409 smtp_printf("250 %u byte chunk received\r\n", chunking_datasize);
410
411 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
412 QUIT, RSET or NOOP but handling them seems obvious */
413
414 next_cmd:
415 switch(smtp_read_command(TRUE))
416 {
417 default:
418 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
419 US"only BDAT permissible after non-LAST BDAT");
420
421 repeat_until_rset:
422 switch(smtp_read_command(TRUE))
423 {
424 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
425 case EOF_CMD: return EOF;
426 case RSET_CMD: smtp_rset_handler(); return ERR;
427 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
428 US"only RSET accepted now") > 0)
429 return EOF;
430 goto repeat_until_rset;
431 }
432
433 case QUIT_CMD:
434 smtp_quit_handler(&user_msg, &log_msg);
435 /*FALLTHROUGH*/
436 case EOF_CMD:
437 return EOF;
438
439 case RSET_CMD:
440 smtp_rset_handler();
441 return ERR;
442
443 case NOOP_CMD:
444 HAD(SCH_NOOP);
445 smtp_printf("250 OK\r\n");
446 goto next_cmd;
447
448 case BDAT_CMD:
449 {
450 int n;
451
452 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
453 {
454 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
455 US"missing size for BDAT command");
456 return ERR;
457 }
458 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
459 ? CHUNKING_LAST : CHUNKING_ACTIVE;
460 chunking_data_left = chunking_datasize;
461
462 if (chunking_datasize == 0)
463 if (chunking_state == CHUNKING_LAST)
464 return EOD;
465 else
466 {
467 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
468 US"zero size for BDAT command");
469 goto repeat_until_rset;
470 }
471
472 receive_getc = bdat_getc;
473 receive_ungetc = bdat_ungetc;
474 break; /* to top of main loop */
475 }
476 }
477 }
478 }
479
480 static void
481 bdat_flush_data(void)
482 {
483 while (chunking_data_left-- > 0)
484 if (lwr_receive_getc() < 0)
485 break;
486
487 receive_getc = lwr_receive_getc;
488 receive_ungetc = lwr_receive_ungetc;
489
490 if (chunking_state != CHUNKING_LAST)
491 chunking_state = CHUNKING_OFFERED;
492 }
493
494
495
496
497 /*************************************************
498 * SMTP version of ungetc() *
499 *************************************************/
500
501 /* Puts a character back in the input buffer. Only ever
502 called once.
503
504 Arguments:
505 ch the character
506
507 Returns: the character
508 */
509
510 int
511 smtp_ungetc(int ch)
512 {
513 *--smtp_inptr = ch;
514 return ch;
515 }
516
517
518 int
519 bdat_ungetc(int ch)
520 {
521 chunking_data_left++;
522 return lwr_receive_ungetc(ch);
523 }
524
525
526
527 /*************************************************
528 * SMTP version of feof() *
529 *************************************************/
530
531 /* Tests for a previous EOF
532
533 Arguments: none
534 Returns: non-zero if the eof flag is set
535 */
536
537 int
538 smtp_feof(void)
539 {
540 return smtp_had_eof;
541 }
542
543
544
545
546 /*************************************************
547 * SMTP version of ferror() *
548 *************************************************/
549
550 /* Tests for a previous read error, and returns with errno
551 restored to what it was when the error was detected.
552
553 Arguments: none
554 Returns: non-zero if the error flag is set
555 */
556
557 int
558 smtp_ferror(void)
559 {
560 errno = smtp_had_error;
561 return smtp_had_error;
562 }
563
564
565
566 /*************************************************
567 * Test for characters in the SMTP buffer *
568 *************************************************/
569
570 /* Used at the end of a message
571
572 Arguments: none
573 Returns: TRUE/FALSE
574 */
575
576 BOOL
577 smtp_buffered(void)
578 {
579 return smtp_inptr < smtp_inend;
580 }
581
582
583
584 /*************************************************
585 * Write formatted string to SMTP channel *
586 *************************************************/
587
588 /* This is a separate function so that we don't have to repeat everything for
589 TLS support or debugging. It is global so that the daemon and the
590 authentication functions can use it. It does not return any error indication,
591 because major problems such as dropped connections won't show up till an output
592 flush for non-TLS connections. The smtp_fflush() function is available for
593 checking that: for convenience, TLS output errors are remembered here so that
594 they are also picked up later by smtp_fflush().
595
596 Arguments:
597 format format string
598 ... optional arguments
599
600 Returns: nothing
601 */
602
603 void
604 smtp_printf(const char *format, ...)
605 {
606 va_list ap;
607
608 va_start(ap, format);
609 smtp_vprintf(format, ap);
610 va_end(ap);
611 }
612
613 /* This is split off so that verify.c:respond_printf() can, in effect, call
614 smtp_printf(), bearing in mind that in C a vararg function can't directly
615 call another vararg function, only a function which accepts a va_list. */
616
617 void
618 smtp_vprintf(const char *format, va_list ap)
619 {
620 BOOL yield;
621
622 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
623
624 DEBUG(D_receive)
625 {
626 void *reset_point = store_get(0);
627 uschar *msg_copy, *cr, *end;
628 msg_copy = string_copy(big_buffer);
629 end = msg_copy + Ustrlen(msg_copy);
630 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
631 memmove(cr, cr + 1, (end--) - cr);
632 debug_printf("SMTP>> %s", msg_copy);
633 store_reset(reset_point);
634 }
635
636 if (!yield)
637 {
638 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
639 smtp_closedown(US"Unexpected error");
640 exim_exit(EXIT_FAILURE);
641 }
642
643 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
644 have had the same. Note: this code is also present in smtp_respond(). It would
645 be tidier to have it only in one place, but when it was added, it was easier to
646 do it that way, so as not to have to mess with the code for the RCPT command,
647 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
648
649 if (rcpt_in_progress)
650 {
651 if (rcpt_smtp_response == NULL)
652 rcpt_smtp_response = string_copy(big_buffer);
653 else if (rcpt_smtp_response_same &&
654 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
655 rcpt_smtp_response_same = FALSE;
656 rcpt_in_progress = FALSE;
657 }
658
659 /* Now write the string */
660
661 #ifdef SUPPORT_TLS
662 if (tls_in.active >= 0)
663 {
664 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
665 smtp_write_error = -1;
666 }
667 else
668 #endif
669
670 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
671 }
672
673
674
675 /*************************************************
676 * Flush SMTP out and check for error *
677 *************************************************/
678
679 /* This function isn't currently used within Exim (it detects errors when it
680 tries to read the next SMTP input), but is available for use in local_scan().
681 For non-TLS connections, it flushes the output and checks for errors. For
682 TLS-connections, it checks for a previously-detected TLS write error.
683
684 Arguments: none
685 Returns: 0 for no error; -1 after an error
686 */
687
688 int
689 smtp_fflush(void)
690 {
691 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
692 return smtp_write_error;
693 }
694
695
696
697 /*************************************************
698 * SMTP command read timeout *
699 *************************************************/
700
701 /* Signal handler for timing out incoming SMTP commands. This attempts to
702 finish off tidily.
703
704 Argument: signal number (SIGALRM)
705 Returns: nothing
706 */
707
708 static void
709 command_timeout_handler(int sig)
710 {
711 sig = sig; /* Keep picky compilers happy */
712 log_write(L_lost_incoming_connection,
713 LOG_MAIN, "SMTP command timeout on%s connection from %s",
714 (tls_in.active >= 0)? " TLS" : "",
715 host_and_ident(FALSE));
716 if (smtp_batched_input)
717 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
718 smtp_notquit_exit(US"command-timeout", US"421",
719 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
720 exim_exit(EXIT_FAILURE);
721 }
722
723
724
725 /*************************************************
726 * SIGTERM received *
727 *************************************************/
728
729 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
730
731 Argument: signal number (SIGTERM)
732 Returns: nothing
733 */
734
735 static void
736 command_sigterm_handler(int sig)
737 {
738 sig = sig; /* Keep picky compilers happy */
739 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
740 if (smtp_batched_input)
741 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
742 smtp_notquit_exit(US"signal-exit", US"421",
743 US"%s: Service not available - closing connection", smtp_active_hostname);
744 exim_exit(EXIT_FAILURE);
745 }
746
747
748
749
750 #ifdef SUPPORT_PROXY
751 /*************************************************
752 * Restore socket timeout to previous value *
753 *************************************************/
754 /* If the previous value was successfully retrieved, restore
755 it before returning control to the non-proxy routines
756
757 Arguments: fd - File descriptor for input
758 get_ok - Successfully retrieved previous values
759 tvtmp - Time struct with previous values
760 vslen - Length of time struct
761 Returns: none
762 */
763 static void
764 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
765 {
766 if (get_ok == 0)
767 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
768 }
769
770 /*************************************************
771 * Check if host is required proxy host *
772 *************************************************/
773 /* The function determines if inbound host will be a regular smtp host
774 or if it is configured that it must use Proxy Protocol.
775
776 Arguments: none
777 Returns: bool
778 */
779
780 static BOOL
781 check_proxy_protocol_host()
782 {
783 int rc;
784 /* Cannot configure local connection as a proxy inbound */
785 if (sender_host_address == NULL) return proxy_session;
786
787 rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
788 sender_host_address, NULL);
789 if (rc == OK)
790 {
791 DEBUG(D_receive)
792 debug_printf("Detected proxy protocol configured host\n");
793 proxy_session = TRUE;
794 }
795 return proxy_session;
796 }
797
798
799 /*************************************************
800 * Setup host for proxy protocol *
801 *************************************************/
802 /* The function configures the connection based on a header from the
803 inbound host to use Proxy Protocol. The specification is very exact
804 so exit with an error if do not find the exact required pieces. This
805 includes an incorrect number of spaces separating args.
806
807 Arguments: none
808 Returns: int
809 */
810
811 static BOOL
812 setup_proxy_protocol_host()
813 {
814 union {
815 struct {
816 uschar line[108];
817 } v1;
818 struct {
819 uschar sig[12];
820 uint8_t ver_cmd;
821 uint8_t fam;
822 uint16_t len;
823 union {
824 struct { /* TCP/UDP over IPv4, len = 12 */
825 uint32_t src_addr;
826 uint32_t dst_addr;
827 uint16_t src_port;
828 uint16_t dst_port;
829 } ip4;
830 struct { /* TCP/UDP over IPv6, len = 36 */
831 uint8_t src_addr[16];
832 uint8_t dst_addr[16];
833 uint16_t src_port;
834 uint16_t dst_port;
835 } ip6;
836 struct { /* AF_UNIX sockets, len = 216 */
837 uschar src_addr[108];
838 uschar dst_addr[108];
839 } unx;
840 } addr;
841 } v2;
842 } hdr;
843
844 /* Temp variables used in PPv2 address:port parsing */
845 uint16_t tmpport;
846 char tmpip[INET_ADDRSTRLEN];
847 struct sockaddr_in tmpaddr;
848 char tmpip6[INET6_ADDRSTRLEN];
849 struct sockaddr_in6 tmpaddr6;
850
851 int get_ok = 0;
852 int size, ret, fd;
853 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
854 uschar *iptype; /* To display debug info */
855 struct timeval tv;
856 socklen_t vslen = 0;
857 struct timeval tvtmp;
858
859 vslen = sizeof(struct timeval);
860
861 fd = fileno(smtp_in);
862
863 /* Save current socket timeout values */
864 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
865 &vslen);
866
867 /* Proxy Protocol host must send header within a short time
868 (default 3 seconds) or it's considered invalid */
869 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
870 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
871 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
872 sizeof(struct timeval));
873
874 do
875 {
876 /* The inbound host was declared to be a Proxy Protocol host, so
877 don't do a PEEK into the data, actually slurp it up. */
878 ret = recv(fd, &hdr, sizeof(hdr), 0);
879 }
880 while (ret == -1 && errno == EINTR);
881
882 if (ret == -1)
883 {
884 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
885 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
886 }
887
888 if (ret >= 16 &&
889 memcmp(&hdr.v2, v2sig, 12) == 0)
890 {
891 uint8_t ver, cmd;
892
893 /* May 2014: haproxy combined the version and command into one byte to
894 allow two full bytes for the length field in order to proxy SSL
895 connections. SSL Proxy is not supported in this version of Exim, but
896 must still seperate values here. */
897 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
898 cmd = (hdr.v2.ver_cmd & 0x0f);
899
900 if (ver != 0x02)
901 {
902 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
903 goto proxyfail;
904 }
905 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
906 /* The v2 header will always be 16 bytes per the spec. */
907 size = 16 + hdr.v2.len;
908 if (ret < size)
909 {
910 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
911 ret, size);
912 goto proxyfail;
913 }
914 switch (cmd)
915 {
916 case 0x01: /* PROXY command */
917 switch (hdr.v2.fam)
918 {
919 case 0x11: /* TCPv4 address type */
920 iptype = US"IPv4";
921 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
922 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
923 if (!string_is_ip_address(US tmpip,NULL))
924 {
925 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
926 return ERRNO_PROXYFAIL;
927 }
928 proxy_local_address = sender_host_address;
929 sender_host_address = string_copy(US tmpip);
930 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
931 proxy_local_port = sender_host_port;
932 sender_host_port = tmpport;
933 /* Save dest ip/port */
934 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
935 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
936 if (!string_is_ip_address(US tmpip,NULL))
937 {
938 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
939 return ERRNO_PROXYFAIL;
940 }
941 proxy_external_address = string_copy(US tmpip);
942 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
943 proxy_external_port = tmpport;
944 goto done;
945 case 0x21: /* TCPv6 address type */
946 iptype = US"IPv6";
947 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
948 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
949 if (!string_is_ip_address(US tmpip6,NULL))
950 {
951 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
952 return ERRNO_PROXYFAIL;
953 }
954 proxy_local_address = sender_host_address;
955 sender_host_address = string_copy(US tmpip6);
956 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
957 proxy_local_port = sender_host_port;
958 sender_host_port = tmpport;
959 /* Save dest ip/port */
960 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
961 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
962 if (!string_is_ip_address(US tmpip6,NULL))
963 {
964 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
965 return ERRNO_PROXYFAIL;
966 }
967 proxy_external_address = string_copy(US tmpip6);
968 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
969 proxy_external_port = tmpport;
970 goto done;
971 default:
972 DEBUG(D_receive)
973 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
974 hdr.v2.fam);
975 goto proxyfail;
976 }
977 /* Unsupported protocol, keep local connection address */
978 break;
979 case 0x00: /* LOCAL command */
980 /* Keep local connection address for LOCAL */
981 break;
982 default:
983 DEBUG(D_receive)
984 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
985 goto proxyfail;
986 }
987 }
988 else if (ret >= 8 &&
989 memcmp(hdr.v1.line, "PROXY", 5) == 0)
990 {
991 uschar *p = string_copy(hdr.v1.line);
992 uschar *end = memchr(p, '\r', ret - 1);
993 uschar *sp; /* Utility variables follow */
994 int tmp_port;
995 char *endc;
996
997 if (!end || end[1] != '\n')
998 {
999 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1000 goto proxyfail;
1001 }
1002 *end = '\0'; /* Terminate the string */
1003 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
1004 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1005 /* Step through the string looking for the required fields. Ensure
1006 strict adherance to required formatting, exit for any error. */
1007 p += 5;
1008 if (!isspace(*(p++)))
1009 {
1010 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1011 goto proxyfail;
1012 }
1013 if (!Ustrncmp(p, CCS"TCP4", 4))
1014 iptype = US"IPv4";
1015 else if (!Ustrncmp(p,CCS"TCP6", 4))
1016 iptype = US"IPv6";
1017 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1018 {
1019 iptype = US"Unknown";
1020 goto done;
1021 }
1022 else
1023 {
1024 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1025 goto proxyfail;
1026 }
1027
1028 p += Ustrlen(iptype);
1029 if (!isspace(*(p++)))
1030 {
1031 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1032 goto proxyfail;
1033 }
1034 /* Find the end of the arg */
1035 if ((sp = Ustrchr(p, ' ')) == NULL)
1036 {
1037 DEBUG(D_receive)
1038 debug_printf("Did not find proxied src %s\n", iptype);
1039 goto proxyfail;
1040 }
1041 *sp = '\0';
1042 if(!string_is_ip_address(p,NULL))
1043 {
1044 DEBUG(D_receive)
1045 debug_printf("Proxied src arg is not an %s address\n", iptype);
1046 goto proxyfail;
1047 }
1048 proxy_local_address = sender_host_address;
1049 sender_host_address = p;
1050 p = sp + 1;
1051 if ((sp = Ustrchr(p, ' ')) == NULL)
1052 {
1053 DEBUG(D_receive)
1054 debug_printf("Did not find proxy dest %s\n", iptype);
1055 goto proxyfail;
1056 }
1057 *sp = '\0';
1058 if(!string_is_ip_address(p,NULL))
1059 {
1060 DEBUG(D_receive)
1061 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1062 goto proxyfail;
1063 }
1064 proxy_external_address = p;
1065 p = sp + 1;
1066 if ((sp = Ustrchr(p, ' ')) == NULL)
1067 {
1068 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1069 goto proxyfail;
1070 }
1071 *sp = '\0';
1072 tmp_port = strtol(CCS p,&endc,10);
1073 if (*endc || tmp_port == 0)
1074 {
1075 DEBUG(D_receive)
1076 debug_printf("Proxied src port '%s' not an integer\n", p);
1077 goto proxyfail;
1078 }
1079 proxy_local_port = sender_host_port;
1080 sender_host_port = tmp_port;
1081 p = sp + 1;
1082 if ((sp = Ustrchr(p, '\0')) == NULL)
1083 {
1084 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1085 goto proxyfail;
1086 }
1087 tmp_port = strtol(CCS p,&endc,10);
1088 if (*endc || tmp_port == 0)
1089 {
1090 DEBUG(D_receive)
1091 debug_printf("Proxy dest port '%s' not an integer\n", p);
1092 goto proxyfail;
1093 }
1094 proxy_external_port = tmp_port;
1095 /* Already checked for /r /n above. Good V1 header received. */
1096 goto done;
1097 }
1098 else
1099 {
1100 /* Wrong protocol */
1101 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1102 goto proxyfail;
1103 }
1104
1105 proxyfail:
1106 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
1107 /* Don't flush any potential buffer contents. Any input should cause a
1108 synchronization failure */
1109 return FALSE;
1110
1111 done:
1112 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
1113 DEBUG(D_receive)
1114 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1115 return proxy_session;
1116 }
1117 #endif
1118
1119 /*************************************************
1120 * Read one command line *
1121 *************************************************/
1122
1123 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1124 There are sites that don't do this, and in any case internal SMTP probably
1125 should check only for LF. Consequently, we check here for LF only. The line
1126 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1127 an unknown command. The command is read into the global smtp_cmd_buffer so that
1128 it is available via $smtp_command.
1129
1130 The character reading routine sets up a timeout for each block actually read
1131 from the input (which may contain more than one command). We set up a special
1132 signal handler that closes down the session on a timeout. Control does not
1133 return when it runs.
1134
1135 Arguments:
1136 check_sync if TRUE, check synchronization rules if global option is TRUE
1137
1138 Returns: a code identifying the command (enumerated above)
1139 */
1140
1141 static int
1142 smtp_read_command(BOOL check_sync)
1143 {
1144 int c;
1145 int ptr = 0;
1146 smtp_cmd_list *p;
1147 BOOL hadnull = FALSE;
1148
1149 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1150
1151 while ((c = (receive_getc)()) != '\n' && c != EOF)
1152 {
1153 if (ptr >= smtp_cmd_buffer_size)
1154 {
1155 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1156 return OTHER_CMD;
1157 }
1158 if (c == 0)
1159 {
1160 hadnull = TRUE;
1161 c = '?';
1162 }
1163 smtp_cmd_buffer[ptr++] = c;
1164 }
1165
1166 receive_linecount++; /* For BSMTP errors */
1167 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1168
1169 /* If hit end of file, return pseudo EOF command. Whether we have a
1170 part-line already read doesn't matter, since this is an error state. */
1171
1172 if (c == EOF) return EOF_CMD;
1173
1174 /* Remove any CR and white space at the end of the line, and terminate the
1175 string. */
1176
1177 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1178 smtp_cmd_buffer[ptr] = 0;
1179
1180 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1181
1182 /* NULLs are not allowed in SMTP commands */
1183
1184 if (hadnull) return BADCHAR_CMD;
1185
1186 /* Scan command list and return identity, having set the data pointer
1187 to the start of the actual data characters. Check for SMTP synchronization
1188 if required. */
1189
1190 for (p = cmd_list; p < cmd_list_end; p++)
1191 {
1192 #ifdef SUPPORT_PROXY
1193 /* Only allow QUIT command if Proxy Protocol parsing failed */
1194 if (proxy_session && proxy_session_failed)
1195 {
1196 if (p->cmd != QUIT_CMD)
1197 continue;
1198 }
1199 #endif
1200 if ( p->len
1201 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1202 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1203 || smtp_cmd_buffer[p->len] == 0
1204 || smtp_cmd_buffer[p->len] == ' '
1205 ) )
1206 {
1207 if (smtp_inptr < smtp_inend && /* Outstanding input */
1208 p->cmd < sync_cmd_limit && /* Command should sync */
1209 check_sync && /* Local flag set */
1210 smtp_enforce_sync && /* Global flag set */
1211 sender_host_address != NULL && /* Not local input */
1212 !sender_host_notsocket) /* Really is a socket */
1213 return BADSYN_CMD;
1214
1215 /* The variables $smtp_command and $smtp_command_argument point into the
1216 unmodified input buffer. A copy of the latter is taken for actual
1217 processing, so that it can be chopped up into separate parts if necessary,
1218 for example, when processing a MAIL command options such as SIZE that can
1219 follow the sender address. */
1220
1221 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1222 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1223 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1224 smtp_cmd_data = smtp_data_buffer;
1225
1226 /* Count non-mail commands from those hosts that are controlled in this
1227 way. The default is all hosts. We don't waste effort checking the list
1228 until we get a non-mail command, but then cache the result to save checking
1229 again. If there's a DEFER while checking the host, assume it's in the list.
1230
1231 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1232 start of each incoming message by fiddling with the value in the table. */
1233
1234 if (!p->is_mail_cmd)
1235 {
1236 if (count_nonmail == TRUE_UNSET) count_nonmail =
1237 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1238 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1239 return TOO_MANY_NONMAIL_CMD;
1240 }
1241
1242 /* If there is data for a command that does not expect it, generate the
1243 error here. */
1244
1245 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1246 }
1247 }
1248
1249 #ifdef SUPPORT_PROXY
1250 /* Only allow QUIT command if Proxy Protocol parsing failed */
1251 if (proxy_session && proxy_session_failed)
1252 return PROXY_FAIL_IGNORE_CMD;
1253 #endif
1254
1255 /* Enforce synchronization for unknown commands */
1256
1257 if (smtp_inptr < smtp_inend && /* Outstanding input */
1258 check_sync && /* Local flag set */
1259 smtp_enforce_sync && /* Global flag set */
1260 sender_host_address != NULL && /* Not local input */
1261 !sender_host_notsocket) /* Really is a socket */
1262 return BADSYN_CMD;
1263
1264 return OTHER_CMD;
1265 }
1266
1267
1268
1269 /*************************************************
1270 * Recheck synchronization *
1271 *************************************************/
1272
1273 /* Synchronization checks can never be perfect because a packet may be on its
1274 way but not arrived when the check is done. Such checks can in any case only be
1275 done when TLS is not in use. Normally, the checks happen when commands are
1276 read: Exim ensures that there is no more input in the input buffer. In normal
1277 cases, the response to the command will be fast, and there is no further check.
1278
1279 However, for some commands an ACL is run, and that can include delays. In those
1280 cases, it is useful to do another check on the input just before sending the
1281 response. This also applies at the start of a connection. This function does
1282 that check by means of the select() function, as long as the facility is not
1283 disabled or inappropriate. A failure of select() is ignored.
1284
1285 When there is unwanted input, we read it so that it appears in the log of the
1286 error.
1287
1288 Arguments: none
1289 Returns: TRUE if all is well; FALSE if there is input pending
1290 */
1291
1292 static BOOL
1293 check_sync(void)
1294 {
1295 int fd, rc;
1296 fd_set fds;
1297 struct timeval tzero;
1298
1299 if (!smtp_enforce_sync || sender_host_address == NULL ||
1300 sender_host_notsocket || tls_in.active >= 0)
1301 return TRUE;
1302
1303 fd = fileno(smtp_in);
1304 FD_ZERO(&fds);
1305 FD_SET(fd, &fds);
1306 tzero.tv_sec = 0;
1307 tzero.tv_usec = 0;
1308 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1309
1310 if (rc <= 0) return TRUE; /* Not ready to read */
1311 rc = smtp_getc();
1312 if (rc < 0) return TRUE; /* End of file or error */
1313
1314 smtp_ungetc(rc);
1315 rc = smtp_inend - smtp_inptr;
1316 if (rc > 150) rc = 150;
1317 smtp_inptr[rc] = 0;
1318 return FALSE;
1319 }
1320
1321
1322
1323 /*************************************************
1324 * Forced closedown of call *
1325 *************************************************/
1326
1327 /* This function is called from log.c when Exim is dying because of a serious
1328 disaster, and also from some other places. If an incoming non-batched SMTP
1329 channel is open, it swallows the rest of the incoming message if in the DATA
1330 phase, sends the reply string, and gives an error to all subsequent commands
1331 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1332 smtp_in.
1333
1334 Arguments:
1335 message SMTP reply string to send, excluding the code
1336
1337 Returns: nothing
1338 */
1339
1340 void
1341 smtp_closedown(uschar *message)
1342 {
1343 if (smtp_in == NULL || smtp_batched_input) return;
1344 receive_swallow_smtp();
1345 smtp_printf("421 %s\r\n", message);
1346
1347 for (;;) switch(smtp_read_command(FALSE))
1348 {
1349 case EOF_CMD:
1350 return;
1351
1352 case QUIT_CMD:
1353 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1354 mac_smtp_fflush();
1355 return;
1356
1357 case RSET_CMD:
1358 smtp_printf("250 Reset OK\r\n");
1359 break;
1360
1361 default:
1362 smtp_printf("421 %s\r\n", message);
1363 break;
1364 }
1365 }
1366
1367
1368
1369
1370 /*************************************************
1371 * Set up connection info for logging *
1372 *************************************************/
1373
1374 /* This function is called when logging information about an SMTP connection.
1375 It sets up appropriate source information, depending on the type of connection.
1376 If sender_fullhost is NULL, we are at a very early stage of the connection;
1377 just use the IP address.
1378
1379 Argument: none
1380 Returns: a string describing the connection
1381 */
1382
1383 uschar *
1384 smtp_get_connection_info(void)
1385 {
1386 uschar *hostname = (sender_fullhost == NULL)?
1387 sender_host_address : sender_fullhost;
1388
1389 if (host_checking)
1390 return string_sprintf("SMTP connection from %s", hostname);
1391
1392 if (sender_host_unknown || sender_host_notsocket)
1393 return string_sprintf("SMTP connection from %s", sender_ident);
1394
1395 if (is_inetd)
1396 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1397
1398 if (LOGGING(incoming_interface) && interface_address != NULL)
1399 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1400 interface_address, interface_port);
1401
1402 return string_sprintf("SMTP connection from %s", hostname);
1403 }
1404
1405
1406
1407 #ifdef SUPPORT_TLS
1408 /* Append TLS-related information to a log line
1409
1410 Arguments:
1411 s String under construction: allocated string to extend, or NULL
1412 sizep Pointer to current allocation size (update on return), or NULL
1413 ptrp Pointer to index for new entries in string (update on return), or NULL
1414
1415 Returns: Allocated string or NULL
1416 */
1417 static uschar *
1418 s_tlslog(uschar * s, int * sizep, int * ptrp)
1419 {
1420 int size = sizep ? *sizep : 0;
1421 int ptr = ptrp ? *ptrp : 0;
1422
1423 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1424 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1425 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1426 s = string_append(s, &size, &ptr, 2, US" CV=",
1427 tls_in.certificate_verified? "yes":"no");
1428 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1429 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1430 string_printing(tls_in.peerdn), US"\"");
1431 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1432 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1433 string_printing(tls_in.sni), US"\"");
1434
1435 if (s)
1436 {
1437 s[ptr] = '\0';
1438 if (sizep) *sizep = size;
1439 if (ptrp) *ptrp = ptr;
1440 }
1441 return s;
1442 }
1443 #endif
1444
1445 /*************************************************
1446 * Log lack of MAIL if so configured *
1447 *************************************************/
1448
1449 /* This function is called when an SMTP session ends. If the log selector
1450 smtp_no_mail is set, write a log line giving some details of what has happened
1451 in the SMTP session.
1452
1453 Arguments: none
1454 Returns: nothing
1455 */
1456
1457 void
1458 smtp_log_no_mail(void)
1459 {
1460 int size, ptr, i;
1461 uschar *s, *sep;
1462
1463 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1464 return;
1465
1466 s = NULL;
1467 size = ptr = 0;
1468
1469 if (sender_host_authenticated != NULL)
1470 {
1471 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1472 if (authenticated_id != NULL)
1473 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1474 }
1475
1476 #ifdef SUPPORT_TLS
1477 s = s_tlslog(s, &size, &ptr);
1478 #endif
1479
1480 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1481 US" C=..." : US" C=";
1482 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1483 {
1484 if (smtp_connection_had[i] != SCH_NONE)
1485 {
1486 s = string_append(s, &size, &ptr, 2, sep,
1487 smtp_names[smtp_connection_had[i]]);
1488 sep = US",";
1489 }
1490 }
1491
1492 for (i = 0; i < smtp_ch_index; i++)
1493 {
1494 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1495 sep = US",";
1496 }
1497
1498 if (s != NULL) s[ptr] = 0; else s = US"";
1499 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1500 host_and_ident(FALSE),
1501 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1502 s);
1503 }
1504
1505
1506
1507 /*************************************************
1508 * Check HELO line and set sender_helo_name *
1509 *************************************************/
1510
1511 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1512 the domain name of the sending host, or an ip literal in square brackets. The
1513 arrgument is placed in sender_helo_name, which is in malloc store, because it
1514 must persist over multiple incoming messages. If helo_accept_junk is set, this
1515 host is permitted to send any old junk (needed for some broken hosts).
1516 Otherwise, helo_allow_chars can be used for rogue characters in general
1517 (typically people want to let in underscores).
1518
1519 Argument:
1520 s the data portion of the line (already past any white space)
1521
1522 Returns: TRUE or FALSE
1523 */
1524
1525 static BOOL
1526 check_helo(uschar *s)
1527 {
1528 uschar *start = s;
1529 uschar *end = s + Ustrlen(s);
1530 BOOL yield = helo_accept_junk;
1531
1532 /* Discard any previous helo name */
1533
1534 if (sender_helo_name != NULL)
1535 {
1536 store_free(sender_helo_name);
1537 sender_helo_name = NULL;
1538 }
1539
1540 /* Skip tests if junk is permitted. */
1541
1542 if (!yield)
1543 {
1544 /* Allow the new standard form for IPv6 address literals, namely,
1545 [IPv6:....], and because someone is bound to use it, allow an equivalent
1546 IPv4 form. Allow plain addresses as well. */
1547
1548 if (*s == '[')
1549 {
1550 if (end[-1] == ']')
1551 {
1552 end[-1] = 0;
1553 if (strncmpic(s, US"[IPv6:", 6) == 0)
1554 yield = (string_is_ip_address(s+6, NULL) == 6);
1555 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1556 yield = (string_is_ip_address(s+6, NULL) == 4);
1557 else
1558 yield = (string_is_ip_address(s+1, NULL) != 0);
1559 end[-1] = ']';
1560 }
1561 }
1562
1563 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1564 that have been configured (usually underscore - sigh). */
1565
1566 else if (*s != 0)
1567 {
1568 yield = TRUE;
1569 while (*s != 0)
1570 {
1571 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1572 Ustrchr(helo_allow_chars, *s) == NULL)
1573 {
1574 yield = FALSE;
1575 break;
1576 }
1577 s++;
1578 }
1579 }
1580 }
1581
1582 /* Save argument if OK */
1583
1584 if (yield) sender_helo_name = string_copy_malloc(start);
1585 return yield;
1586 }
1587
1588
1589
1590
1591
1592 /*************************************************
1593 * Extract SMTP command option *
1594 *************************************************/
1595
1596 /* This function picks the next option setting off the end of smtp_cmd_data. It
1597 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1598 things that can appear there.
1599
1600 Arguments:
1601 name point this at the name
1602 value point this at the data string
1603
1604 Returns: TRUE if found an option
1605 */
1606
1607 static BOOL
1608 extract_option(uschar **name, uschar **value)
1609 {
1610 uschar *n;
1611 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1612 while (isspace(*v)) v--;
1613 v[1] = 0;
1614 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1615
1616 n = v;
1617 if (*v == '=')
1618 {
1619 while(isalpha(n[-1])) n--;
1620 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1621 if (!isspace(n[-1])) return FALSE;
1622 n[-1] = 0;
1623 }
1624 else
1625 {
1626 n++;
1627 if (v == smtp_cmd_data) return FALSE;
1628 }
1629 *v++ = 0;
1630 *name = n;
1631 *value = v;
1632 return TRUE;
1633 }
1634
1635
1636
1637
1638
1639 /*************************************************
1640 * Reset for new message *
1641 *************************************************/
1642
1643 /* This function is called whenever the SMTP session is reset from
1644 within either of the setup functions.
1645
1646 Argument: the stacking pool storage reset point
1647 Returns: nothing
1648 */
1649
1650 static void
1651 smtp_reset(void *reset_point)
1652 {
1653 store_reset(reset_point);
1654 recipients_list = NULL;
1655 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1656 raw_recipients_count = recipients_count = recipients_list_max = 0;
1657 cancel_cutthrough_connection("smtp reset");
1658 message_linecount = 0;
1659 message_size = -1;
1660 acl_added_headers = NULL;
1661 acl_removed_headers = NULL;
1662 queue_only_policy = FALSE;
1663 rcpt_smtp_response = NULL;
1664 rcpt_smtp_response_same = TRUE;
1665 rcpt_in_progress = FALSE;
1666 deliver_freeze = FALSE; /* Can be set by ACL */
1667 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1668 fake_response = OK; /* Can be set by ACL */
1669 #ifdef WITH_CONTENT_SCAN
1670 no_mbox_unspool = FALSE; /* Can be set by ACL */
1671 #endif
1672 submission_mode = FALSE; /* Can be set by ACL */
1673 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1674 active_local_from_check = local_from_check; /* Can be set by ACL */
1675 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1676 sender_address = NULL;
1677 submission_name = NULL; /* Can be set by ACL */
1678 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1679 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1680 sender_verified_list = NULL; /* No senders verified */
1681 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1682 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1683
1684 authenticated_sender = NULL;
1685 #ifdef EXPERIMENTAL_BRIGHTMAIL
1686 bmi_run = 0;
1687 bmi_verdicts = NULL;
1688 #endif
1689 #ifndef DISABLE_DKIM
1690 dkim_signers = NULL;
1691 dkim_disable_verify = FALSE;
1692 dkim_collect_input = FALSE;
1693 #endif
1694 dsn_ret = 0;
1695 dsn_envid = NULL;
1696 #ifndef DISABLE_PRDR
1697 prdr_requested = FALSE;
1698 #endif
1699 #ifdef EXPERIMENTAL_SPF
1700 spf_header_comment = NULL;
1701 spf_received = NULL;
1702 spf_result = NULL;
1703 spf_smtp_comment = NULL;
1704 #endif
1705 #ifdef SUPPORT_I18N
1706 message_smtputf8 = FALSE;
1707 #endif
1708 body_linecount = body_zerocount = 0;
1709
1710 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1711 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1712 /* Note that ratelimiters_conn persists across resets. */
1713
1714 /* Reset message ACL variables */
1715
1716 acl_var_m = NULL;
1717
1718 /* The message body variables use malloc store. They may be set if this is
1719 not the first message in an SMTP session and the previous message caused them
1720 to be referenced in an ACL. */
1721
1722 if (message_body != NULL)
1723 {
1724 store_free(message_body);
1725 message_body = NULL;
1726 }
1727
1728 if (message_body_end != NULL)
1729 {
1730 store_free(message_body_end);
1731 message_body_end = NULL;
1732 }
1733
1734 /* Warning log messages are also saved in malloc store. They are saved to avoid
1735 repetition in the same message, but it seems right to repeat them for different
1736 messages. */
1737
1738 while (acl_warn_logged != NULL)
1739 {
1740 string_item *this = acl_warn_logged;
1741 acl_warn_logged = acl_warn_logged->next;
1742 store_free(this);
1743 }
1744 }
1745
1746
1747
1748
1749
1750 /*************************************************
1751 * Initialize for incoming batched SMTP message *
1752 *************************************************/
1753
1754 /* This function is called from smtp_setup_msg() in the case when
1755 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1756 of messages in one file with SMTP commands between them. All errors must be
1757 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1758 relevant. After an error on a sender, or an invalid recipient, the remainder
1759 of the message is skipped. The value of received_protocol is already set.
1760
1761 Argument: none
1762 Returns: > 0 message successfully started (reached DATA)
1763 = 0 QUIT read or end of file reached
1764 < 0 should not occur
1765 */
1766
1767 static int
1768 smtp_setup_batch_msg(void)
1769 {
1770 int done = 0;
1771 void *reset_point = store_get(0);
1772
1773 /* Save the line count at the start of each transaction - single commands
1774 like HELO and RSET count as whole transactions. */
1775
1776 bsmtp_transaction_linecount = receive_linecount;
1777
1778 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1779
1780 smtp_reset(reset_point); /* Reset for start of message */
1781
1782 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1783 value. The values are 2 larger than the required yield of the function. */
1784
1785 while (done <= 0)
1786 {
1787 uschar *errmess;
1788 uschar *recipient = NULL;
1789 int start, end, sender_domain, recipient_domain;
1790
1791 switch(smtp_read_command(FALSE))
1792 {
1793 /* The HELO/EHLO commands set sender_address_helo if they have
1794 valid data; otherwise they are ignored, except that they do
1795 a reset of the state. */
1796
1797 case HELO_CMD:
1798 case EHLO_CMD:
1799
1800 check_helo(smtp_cmd_data);
1801 /* Fall through */
1802
1803 case RSET_CMD:
1804 smtp_reset(reset_point);
1805 bsmtp_transaction_linecount = receive_linecount;
1806 break;
1807
1808
1809 /* The MAIL FROM command requires an address as an operand. All we
1810 do here is to parse it for syntactic correctness. The form "<>" is
1811 a special case which converts into an empty string. The start/end
1812 pointers in the original are not used further for this address, as
1813 it is the canonical extracted address which is all that is kept. */
1814
1815 case MAIL_CMD:
1816 smtp_mailcmd_count++; /* Count for no-mail log */
1817 if (sender_address != NULL)
1818 /* The function moan_smtp_batch() does not return. */
1819 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1820
1821 if (smtp_cmd_data[0] == 0)
1822 /* The function moan_smtp_batch() does not return. */
1823 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1824
1825 /* Reset to start of message */
1826
1827 smtp_reset(reset_point);
1828
1829 /* Apply SMTP rewrite */
1830
1831 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1832 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1833 US"", global_rewrite_rules) : smtp_cmd_data;
1834
1835 /* Extract the address; the TRUE flag allows <> as valid */
1836
1837 raw_sender =
1838 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1839 TRUE);
1840
1841 if (raw_sender == NULL)
1842 /* The function moan_smtp_batch() does not return. */
1843 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1844
1845 sender_address = string_copy(raw_sender);
1846
1847 /* Qualify unqualified sender addresses if permitted to do so. */
1848
1849 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1850 {
1851 if (allow_unqualified_sender)
1852 {
1853 sender_address = rewrite_address_qualify(sender_address, FALSE);
1854 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1855 "and rewritten\n", raw_sender);
1856 }
1857 /* The function moan_smtp_batch() does not return. */
1858 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1859 "a domain");
1860 }
1861 break;
1862
1863
1864 /* The RCPT TO command requires an address as an operand. All we do
1865 here is to parse it for syntactic correctness. There may be any number
1866 of RCPT TO commands, specifying multiple senders. We build them all into
1867 a data structure that is in argc/argv format. The start/end values
1868 given by parse_extract_address are not used, as we keep only the
1869 extracted address. */
1870
1871 case RCPT_CMD:
1872 if (sender_address == NULL)
1873 /* The function moan_smtp_batch() does not return. */
1874 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1875
1876 if (smtp_cmd_data[0] == 0)
1877 /* The function moan_smtp_batch() does not return. */
1878 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1879
1880 /* Check maximum number allowed */
1881
1882 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1883 /* The function moan_smtp_batch() does not return. */
1884 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1885 recipients_max_reject? "552": "452");
1886
1887 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1888 recipient address */
1889
1890 recipient = rewrite_existflags & rewrite_smtp
1891 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1892 global_rewrite_rules)
1893 : smtp_cmd_data;
1894
1895 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1896 &recipient_domain, FALSE);
1897
1898 if (!recipient)
1899 /* The function moan_smtp_batch() does not return. */
1900 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1901
1902 /* If the recipient address is unqualified, qualify it if permitted. Then
1903 add it to the list of recipients. */
1904
1905 if (recipient_domain == 0)
1906 {
1907 if (allow_unqualified_recipient)
1908 {
1909 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1910 recipient);
1911 recipient = rewrite_address_qualify(recipient, TRUE);
1912 }
1913 /* The function moan_smtp_batch() does not return. */
1914 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1915 "a domain");
1916 }
1917 receive_add_recipient(recipient, -1);
1918 break;
1919
1920
1921 /* The DATA command is legal only if it follows successful MAIL FROM
1922 and RCPT TO commands. This function is complete when a valid DATA
1923 command is encountered. */
1924
1925 case DATA_CMD:
1926 if (sender_address == NULL || recipients_count <= 0)
1927 {
1928 /* The function moan_smtp_batch() does not return. */
1929 if (sender_address == NULL)
1930 moan_smtp_batch(smtp_cmd_buffer,
1931 "503 MAIL FROM:<sender> command must precede DATA");
1932 else
1933 moan_smtp_batch(smtp_cmd_buffer,
1934 "503 RCPT TO:<recipient> must precede DATA");
1935 }
1936 else
1937 {
1938 done = 3; /* DATA successfully achieved */
1939 message_ended = END_NOTENDED; /* Indicate in middle of message */
1940 }
1941 break;
1942
1943
1944 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1945
1946 case VRFY_CMD:
1947 case EXPN_CMD:
1948 case HELP_CMD:
1949 case NOOP_CMD:
1950 case ETRN_CMD:
1951 bsmtp_transaction_linecount = receive_linecount;
1952 break;
1953
1954
1955 case EOF_CMD:
1956 case QUIT_CMD:
1957 done = 2;
1958 break;
1959
1960
1961 case BADARG_CMD:
1962 /* The function moan_smtp_batch() does not return. */
1963 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1964 break;
1965
1966
1967 case BADCHAR_CMD:
1968 /* The function moan_smtp_batch() does not return. */
1969 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1970 break;
1971
1972
1973 default:
1974 /* The function moan_smtp_batch() does not return. */
1975 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1976 break;
1977 }
1978 }
1979
1980 return done - 2; /* Convert yield values */
1981 }
1982
1983
1984
1985
1986 /*************************************************
1987 * Start an SMTP session *
1988 *************************************************/
1989
1990 /* This function is called at the start of an SMTP session. Thereafter,
1991 smtp_setup_msg() is called to initiate each separate message. This
1992 function does host-specific testing, and outputs the banner line.
1993
1994 Arguments: none
1995 Returns: FALSE if the session can not continue; something has
1996 gone wrong, or the connection to the host is blocked
1997 */
1998
1999 BOOL
2000 smtp_start_session(void)
2001 {
2002 int size = 256;
2003 int ptr, esclen;
2004 uschar *user_msg, *log_msg;
2005 uschar *code, *esc;
2006 uschar *p, *s, *ss;
2007
2008 smtp_connection_start = time(NULL);
2009 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2010 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2011 smtp_ch_index = 0;
2012
2013 /* Default values for certain variables */
2014
2015 helo_seen = esmtp = helo_accept_junk = FALSE;
2016 smtp_mailcmd_count = 0;
2017 count_nonmail = TRUE_UNSET;
2018 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2019 smtp_delay_mail = smtp_rlm_base;
2020 auth_advertised = FALSE;
2021 pipelining_advertised = FALSE;
2022 pipelining_enable = TRUE;
2023 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2024 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2025
2026 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2027 authentication settings from -oMaa to remain in force. */
2028
2029 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2030 authenticated_by = NULL;
2031
2032 #ifdef SUPPORT_TLS
2033 tls_in.cipher = tls_in.peerdn = NULL;
2034 tls_in.ourcert = tls_in.peercert = NULL;
2035 tls_in.sni = NULL;
2036 tls_in.ocsp = OCSP_NOT_REQ;
2037 tls_advertised = FALSE;
2038 #endif
2039 dsn_advertised = FALSE;
2040 #ifdef SUPPORT_I18N
2041 smtputf8_advertised = FALSE;
2042 #endif
2043
2044 /* Reset ACL connection variables */
2045
2046 acl_var_c = NULL;
2047
2048 /* Allow for trailing 0 in the command and data buffers. */
2049
2050 if (!(smtp_cmd_buffer = US malloc(2*smtp_cmd_buffer_size + 2)))
2051 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2052 "malloc() failed for SMTP command buffer");
2053
2054 smtp_cmd_buffer[0] = 0;
2055 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
2056
2057 /* For batched input, the protocol setting can be overridden from the
2058 command line by a trusted caller. */
2059
2060 if (smtp_batched_input)
2061 {
2062 if (!received_protocol) received_protocol = US"local-bsmtp";
2063 }
2064
2065 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2066 reset later if any of EHLO/AUTH/STARTTLS are received. */
2067
2068 else
2069 received_protocol =
2070 (sender_host_address ? protocols : protocols_local) [pnormal];
2071
2072 /* Set up the buffer for inputting using direct read() calls, and arrange to
2073 call the local functions instead of the standard C ones. */
2074
2075 if (!(smtp_inbuffer = (uschar *)malloc(in_buffer_size)))
2076 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2077
2078 receive_getc = smtp_getc;
2079 receive_get_cache = smtp_get_cache;
2080 receive_ungetc = smtp_ungetc;
2081 receive_feof = smtp_feof;
2082 receive_ferror = smtp_ferror;
2083 receive_smtp_buffered = smtp_buffered;
2084 smtp_inptr = smtp_inend = smtp_inbuffer;
2085 smtp_had_eof = smtp_had_error = 0;
2086
2087 /* Set up the message size limit; this may be host-specific */
2088
2089 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2090 if (expand_string_message != NULL)
2091 {
2092 if (thismessage_size_limit == -1)
2093 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2094 "%s", expand_string_message);
2095 else
2096 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2097 "%s", expand_string_message);
2098 smtp_closedown(US"Temporary local problem - please try later");
2099 return FALSE;
2100 }
2101
2102 /* When a message is input locally via the -bs or -bS options, sender_host_
2103 unknown is set unless -oMa was used to force an IP address, in which case it
2104 is checked like a real remote connection. When -bs is used from inetd, this
2105 flag is not set, causing the sending host to be checked. The code that deals
2106 with IP source routing (if configured) is never required for -bs or -bS and
2107 the flag sender_host_notsocket is used to suppress it.
2108
2109 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2110 reserve for certain hosts and/or networks. */
2111
2112 if (!sender_host_unknown)
2113 {
2114 int rc;
2115 BOOL reserved_host = FALSE;
2116
2117 /* Look up IP options (source routing info) on the socket if this is not an
2118 -oMa "host", and if any are found, log them and drop the connection.
2119
2120 Linux (and others now, see below) is different to everyone else, so there
2121 has to be some conditional compilation here. Versions of Linux before 2.1.15
2122 used a structure whose name was "options". Somebody finally realized that
2123 this name was silly, and it got changed to "ip_options". I use the
2124 newer name here, but there is a fudge in the script that sets up os.h
2125 to define a macro in older Linux systems.
2126
2127 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2128 glibc 2, which has chosen ip_opts for the structure name. This is now
2129 really a glibc thing rather than a Linux thing, so the condition name
2130 has been changed to reflect this. It is relevant also to GNU/Hurd.
2131
2132 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2133 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2134 a special macro defined in the os.h file.
2135
2136 Some DGUX versions on older hardware appear not to support IP options at
2137 all, so there is now a general macro which can be set to cut out this
2138 support altogether.
2139
2140 How to do this properly in IPv6 is not yet known. */
2141
2142 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2143
2144 #ifdef GLIBC_IP_OPTIONS
2145 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2146 #define OPTSTYLE 1
2147 #else
2148 #define OPTSTYLE 2
2149 #endif
2150 #elif defined DARWIN_IP_OPTIONS
2151 #define OPTSTYLE 2
2152 #else
2153 #define OPTSTYLE 3
2154 #endif
2155
2156 if (!host_checking && !sender_host_notsocket)
2157 {
2158 #if OPTSTYLE == 1
2159 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2160 struct ip_options *ipopt = store_get(optlen);
2161 #elif OPTSTYLE == 2
2162 struct ip_opts ipoptblock;
2163 struct ip_opts *ipopt = &ipoptblock;
2164 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2165 #else
2166 struct ipoption ipoptblock;
2167 struct ipoption *ipopt = &ipoptblock;
2168 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2169 #endif
2170
2171 /* Occasional genuine failures of getsockopt() have been seen - for
2172 example, "reset by peer". Therefore, just log and give up on this
2173 call, unless the error is ENOPROTOOPT. This error is given by systems
2174 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2175 of writing. So for that error, carry on - we just can't do an IP options
2176 check. */
2177
2178 DEBUG(D_receive) debug_printf("checking for IP options\n");
2179
2180 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2181 &optlen) < 0)
2182 {
2183 if (errno != ENOPROTOOPT)
2184 {
2185 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2186 host_and_ident(FALSE), strerror(errno));
2187 smtp_printf("451 SMTP service not available\r\n");
2188 return FALSE;
2189 }
2190 }
2191
2192 /* Deal with any IP options that are set. On the systems I have looked at,
2193 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2194 more logging data than will fit in big_buffer. Nevertheless, after somebody
2195 questioned this code, I've added in some paranoid checking. */
2196
2197 else if (optlen > 0)
2198 {
2199 uschar *p = big_buffer;
2200 uschar *pend = big_buffer + big_buffer_size;
2201 uschar *opt, *adptr;
2202 int optcount;
2203 struct in_addr addr;
2204
2205 #if OPTSTYLE == 1
2206 uschar *optstart = (uschar *)(ipopt->__data);
2207 #elif OPTSTYLE == 2
2208 uschar *optstart = (uschar *)(ipopt->ip_opts);
2209 #else
2210 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2211 #endif
2212
2213 DEBUG(D_receive) debug_printf("IP options exist\n");
2214
2215 Ustrcpy(p, "IP options on incoming call:");
2216 p += Ustrlen(p);
2217
2218 for (opt = optstart; opt != NULL &&
2219 opt < (uschar *)(ipopt) + optlen;)
2220 {
2221 switch (*opt)
2222 {
2223 case IPOPT_EOL:
2224 opt = NULL;
2225 break;
2226
2227 case IPOPT_NOP:
2228 opt++;
2229 break;
2230
2231 case IPOPT_SSRR:
2232 case IPOPT_LSRR:
2233 if (!string_format(p, pend-p, " %s [@%s",
2234 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2235 #if OPTSTYLE == 1
2236 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2237 #elif OPTSTYLE == 2
2238 inet_ntoa(ipopt->ip_dst)))
2239 #else
2240 inet_ntoa(ipopt->ipopt_dst)))
2241 #endif
2242 {
2243 opt = NULL;
2244 break;
2245 }
2246
2247 p += Ustrlen(p);
2248 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2249 adptr = opt + 3;
2250 while (optcount-- > 0)
2251 {
2252 memcpy(&addr, adptr, sizeof(addr));
2253 if (!string_format(p, pend - p - 1, "%s%s",
2254 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2255 {
2256 opt = NULL;
2257 break;
2258 }
2259 p += Ustrlen(p);
2260 adptr += sizeof(struct in_addr);
2261 }
2262 *p++ = ']';
2263 opt += opt[1];
2264 break;
2265
2266 default:
2267 {
2268 int i;
2269 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2270 Ustrcat(p, "[ ");
2271 p += 2;
2272 for (i = 0; i < opt[1]; i++)
2273 {
2274 sprintf(CS p, "%2.2x ", opt[i]);
2275 p += 3;
2276 }
2277 *p++ = ']';
2278 }
2279 opt += opt[1];
2280 break;
2281 }
2282 }
2283
2284 *p = 0;
2285 log_write(0, LOG_MAIN, "%s", big_buffer);
2286
2287 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2288
2289 log_write(0, LOG_MAIN|LOG_REJECT,
2290 "connection from %s refused (IP options)", host_and_ident(FALSE));
2291
2292 smtp_printf("554 SMTP service not available\r\n");
2293 return FALSE;
2294 }
2295
2296 /* Length of options = 0 => there are no options */
2297
2298 else DEBUG(D_receive) debug_printf("no IP options found\n");
2299 }
2300 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2301
2302 /* Set keep-alive in socket options. The option is on by default. This
2303 setting is an attempt to get rid of some hanging connections that stick in
2304 read() when the remote end (usually a dialup) goes away. */
2305
2306 if (smtp_accept_keepalive && !sender_host_notsocket)
2307 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2308
2309 /* If the current host matches host_lookup, set the name by doing a
2310 reverse lookup. On failure, sender_host_name will be NULL and
2311 host_lookup_failed will be TRUE. This may or may not be serious - optional
2312 checks later. */
2313
2314 if (verify_check_host(&host_lookup) == OK)
2315 {
2316 (void)host_name_lookup();
2317 host_build_sender_fullhost();
2318 }
2319
2320 /* Delay this until we have the full name, if it is looked up. */
2321
2322 set_process_info("handling incoming connection from %s",
2323 host_and_ident(FALSE));
2324
2325 /* Expand smtp_receive_timeout, if needed */
2326
2327 if (smtp_receive_timeout_s)
2328 {
2329 uschar * exp;
2330 if ( !(exp = expand_string(smtp_receive_timeout_s))
2331 || !(*exp)
2332 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2333 )
2334 log_write(0, LOG_MAIN|LOG_PANIC,
2335 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2336 }
2337
2338 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2339 smtps port for use with older style SSL MTAs. */
2340
2341 #ifdef SUPPORT_TLS
2342 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2343 return FALSE;
2344 #endif
2345
2346 /* Test for explicit connection rejection */
2347
2348 if (verify_check_host(&host_reject_connection) == OK)
2349 {
2350 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2351 "from %s (host_reject_connection)", host_and_ident(FALSE));
2352 smtp_printf("554 SMTP service not available\r\n");
2353 return FALSE;
2354 }
2355
2356 /* Test with TCP Wrappers if so configured. There is a problem in that
2357 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2358 such as disks dying. In these cases, it is desirable to reject with a 4xx
2359 error instead of a 5xx error. There isn't a "right" way to detect such
2360 problems. The following kludge is used: errno is zeroed before calling
2361 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2362 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2363 not exist). */
2364
2365 #ifdef USE_TCP_WRAPPERS
2366 errno = 0;
2367 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2368 if (tcp_wrappers_name == NULL)
2369 {
2370 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2371 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2372 expand_string_message);
2373 }
2374 if (!hosts_ctl(tcp_wrappers_name,
2375 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2376 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2377 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2378 {
2379 if (errno == 0 || errno == ENOENT)
2380 {
2381 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2382 log_write(L_connection_reject,
2383 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2384 "(tcp wrappers)", host_and_ident(FALSE));
2385 smtp_printf("554 SMTP service not available\r\n");
2386 }
2387 else
2388 {
2389 int save_errno = errno;
2390 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2391 "errno value %d\n", save_errno);
2392 log_write(L_connection_reject,
2393 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2394 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2395 smtp_printf("451 Temporary local problem - please try later\r\n");
2396 }
2397 return FALSE;
2398 }
2399 #endif
2400
2401 /* Check for reserved slots. The value of smtp_accept_count has already been
2402 incremented to include this process. */
2403
2404 if (smtp_accept_max > 0 &&
2405 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2406 {
2407 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2408 {
2409 log_write(L_connection_reject,
2410 LOG_MAIN, "temporarily refused connection from %s: not in "
2411 "reserve list: connected=%d max=%d reserve=%d%s",
2412 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2413 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2414 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2415 "please try again later\r\n", smtp_active_hostname);
2416 return FALSE;
2417 }
2418 reserved_host = TRUE;
2419 }
2420
2421 /* If a load level above which only messages from reserved hosts are
2422 accepted is set, check the load. For incoming calls via the daemon, the
2423 check is done in the superior process if there are no reserved hosts, to
2424 save a fork. In all cases, the load average will already be available
2425 in a global variable at this point. */
2426
2427 if (smtp_load_reserve >= 0 &&
2428 load_average > smtp_load_reserve &&
2429 !reserved_host &&
2430 verify_check_host(&smtp_reserve_hosts) != OK)
2431 {
2432 log_write(L_connection_reject,
2433 LOG_MAIN, "temporarily refused connection from %s: not in "
2434 "reserve list and load average = %.2f", host_and_ident(FALSE),
2435 (double)load_average/1000.0);
2436 smtp_printf("421 %s: Too much load; please try again later\r\n",
2437 smtp_active_hostname);
2438 return FALSE;
2439 }
2440
2441 /* Determine whether unqualified senders or recipients are permitted
2442 for this host. Unfortunately, we have to do this every time, in order to
2443 set the flags so that they can be inspected when considering qualifying
2444 addresses in the headers. For a site that permits no qualification, this
2445 won't take long, however. */
2446
2447 allow_unqualified_sender =
2448 verify_check_host(&sender_unqualified_hosts) == OK;
2449
2450 allow_unqualified_recipient =
2451 verify_check_host(&recipient_unqualified_hosts) == OK;
2452
2453 /* Determine whether HELO/EHLO is required for this host. The requirement
2454 can be hard or soft. */
2455
2456 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2457 if (!helo_required)
2458 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2459
2460 /* Determine whether this hosts is permitted to send syntactic junk
2461 after a HELO or EHLO command. */
2462
2463 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2464 }
2465
2466 /* For batch SMTP input we are now done. */
2467
2468 if (smtp_batched_input) return TRUE;
2469
2470 #ifdef SUPPORT_PROXY
2471 /* If valid Proxy Protocol source is connecting, set up session.
2472 * Failure will not allow any SMTP function other than QUIT. */
2473 proxy_session = FALSE;
2474 proxy_session_failed = FALSE;
2475 if (check_proxy_protocol_host())
2476 if (setup_proxy_protocol_host() == FALSE)
2477 {
2478 proxy_session_failed = TRUE;
2479 DEBUG(D_receive)
2480 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2481 }
2482 else
2483 {
2484 sender_host_name = NULL;
2485 (void)host_name_lookup();
2486 host_build_sender_fullhost();
2487 }
2488 #endif
2489
2490 /* Run the ACL if it exists */
2491
2492 user_msg = NULL;
2493 if (acl_smtp_connect)
2494 {
2495 int rc;
2496 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2497 &log_msg)) != OK)
2498 {
2499 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2500 return FALSE;
2501 }
2502 }
2503
2504 /* Output the initial message for a two-way SMTP connection. It may contain
2505 newlines, which then cause a multi-line response to be given. */
2506
2507 code = US"220"; /* Default status code */
2508 esc = US""; /* Default extended status code */
2509 esclen = 0; /* Length of esc */
2510
2511 if (!user_msg)
2512 {
2513 if (!(s = expand_string(smtp_banner)))
2514 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2515 "failed: %s", smtp_banner, expand_string_message);
2516 }
2517 else
2518 {
2519 int codelen = 3;
2520 s = user_msg;
2521 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2522 if (codelen > 4)
2523 {
2524 esc = code + 4;
2525 esclen = codelen - 4;
2526 }
2527 }
2528
2529 /* Remove any terminating newlines; might as well remove trailing space too */
2530
2531 p = s + Ustrlen(s);
2532 while (p > s && isspace(p[-1])) p--;
2533 *p = 0;
2534
2535 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2536 is all contained in a single IP packet. The original code wrote out the
2537 greeting using several calls to fprint/fputc, and on busy servers this could
2538 cause it to be split over more than one packet - which caused CC:Mail to fall
2539 over when it got the second part of the greeting after sending its first
2540 command. Sigh. To try to avoid this, build the complete greeting message
2541 first, and output it in one fell swoop. This gives a better chance of it
2542 ending up as a single packet. */
2543
2544 ss = store_get(size);
2545 ptr = 0;
2546
2547 p = s;
2548 do /* At least once, in case we have an empty string */
2549 {
2550 int len;
2551 uschar *linebreak = Ustrchr(p, '\n');
2552 ss = string_catn(ss, &size, &ptr, code, 3);
2553 if (linebreak == NULL)
2554 {
2555 len = Ustrlen(p);
2556 ss = string_catn(ss, &size, &ptr, US" ", 1);
2557 }
2558 else
2559 {
2560 len = linebreak - p;
2561 ss = string_catn(ss, &size, &ptr, US"-", 1);
2562 }
2563 ss = string_catn(ss, &size, &ptr, esc, esclen);
2564 ss = string_catn(ss, &size, &ptr, p, len);
2565 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2566 p += len;
2567 if (linebreak != NULL) p++;
2568 }
2569 while (*p != 0);
2570
2571 ss[ptr] = 0; /* string_cat leaves room for this */
2572
2573 /* Before we write the banner, check that there is no input pending, unless
2574 this synchronisation check is disabled. */
2575
2576 if (!check_sync())
2577 {
2578 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2579 "synchronization error (input sent without waiting for greeting): "
2580 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2581 string_printing(smtp_inptr));
2582 smtp_printf("554 SMTP synchronization error\r\n");
2583 return FALSE;
2584 }
2585
2586 /* Now output the banner */
2587
2588 smtp_printf("%s", ss);
2589 return TRUE;
2590 }
2591
2592
2593
2594
2595
2596 /*************************************************
2597 * Handle SMTP syntax and protocol errors *
2598 *************************************************/
2599
2600 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2601 to do so. Then transmit the error response. The return value depends on the
2602 number of syntax and protocol errors in this SMTP session.
2603
2604 Arguments:
2605 type error type, given as a log flag bit
2606 code response code; <= 0 means don't send a response
2607 data data to reflect in the response (can be NULL)
2608 errmess the error message
2609
2610 Returns: -1 limit of syntax/protocol errors NOT exceeded
2611 +1 limit of syntax/protocol errors IS exceeded
2612
2613 These values fit in with the values of the "done" variable in the main
2614 processing loop in smtp_setup_msg(). */
2615
2616 static int
2617 synprot_error(int type, int code, uschar *data, uschar *errmess)
2618 {
2619 int yield = -1;
2620
2621 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2622 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2623 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2624
2625 if (++synprot_error_count > smtp_max_synprot_errors)
2626 {
2627 yield = 1;
2628 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2629 "syntax or protocol errors (last command was \"%s\")",
2630 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2631 }
2632
2633 if (code > 0)
2634 {
2635 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2636 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2637 if (yield == 1)
2638 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2639 }
2640
2641 return yield;
2642 }
2643
2644
2645
2646
2647 /*************************************************
2648 * Log incomplete transactions *
2649 *************************************************/
2650
2651 /* This function is called after a transaction has been aborted by RSET, QUIT,
2652 connection drops or other errors. It logs the envelope information received
2653 so far in order to preserve address verification attempts.
2654
2655 Argument: string to indicate what aborted the transaction
2656 Returns: nothing
2657 */
2658
2659 static void
2660 incomplete_transaction_log(uschar *what)
2661 {
2662 if (sender_address == NULL || /* No transaction in progress */
2663 !LOGGING(smtp_incomplete_transaction))
2664 return;
2665
2666 /* Build list of recipients for logging */
2667
2668 if (recipients_count > 0)
2669 {
2670 int i;
2671 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2672 for (i = 0; i < recipients_count; i++)
2673 raw_recipients[i] = recipients_list[i].address;
2674 raw_recipients_count = recipients_count;
2675 }
2676
2677 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2678 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2679 }
2680
2681
2682
2683
2684 /*************************************************
2685 * Send SMTP response, possibly multiline *
2686 *************************************************/
2687
2688 /* There are, it seems, broken clients out there that cannot handle multiline
2689 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2690 output nothing for non-final calls, and only the first line for anything else.
2691
2692 Arguments:
2693 code SMTP code, may involve extended status codes
2694 codelen length of smtp code; if > 4 there's an ESC
2695 final FALSE if the last line isn't the final line
2696 msg message text, possibly containing newlines
2697
2698 Returns: nothing
2699 */
2700
2701 void
2702 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2703 {
2704 int esclen = 0;
2705 uschar *esc = US"";
2706
2707 if (!final && no_multiline_responses) return;
2708
2709 if (codelen > 4)
2710 {
2711 esc = code + 4;
2712 esclen = codelen - 4;
2713 }
2714
2715 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2716 have had the same. Note: this code is also present in smtp_printf(). It would
2717 be tidier to have it only in one place, but when it was added, it was easier to
2718 do it that way, so as not to have to mess with the code for the RCPT command,
2719 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2720
2721 if (rcpt_in_progress)
2722 {
2723 if (rcpt_smtp_response == NULL)
2724 rcpt_smtp_response = string_copy(msg);
2725 else if (rcpt_smtp_response_same &&
2726 Ustrcmp(rcpt_smtp_response, msg) != 0)
2727 rcpt_smtp_response_same = FALSE;
2728 rcpt_in_progress = FALSE;
2729 }
2730
2731 /* Not output the message, splitting it up into multiple lines if necessary. */
2732
2733 for (;;)
2734 {
2735 uschar *nl = Ustrchr(msg, '\n');
2736 if (nl == NULL)
2737 {
2738 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2739 return;
2740 }
2741 else if (nl[1] == 0 || no_multiline_responses)
2742 {
2743 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2744 (int)(nl - msg), msg);
2745 return;
2746 }
2747 else
2748 {
2749 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2750 msg = nl + 1;
2751 while (isspace(*msg)) msg++;
2752 }
2753 }
2754 }
2755
2756
2757
2758
2759 /*************************************************
2760 * Parse user SMTP message *
2761 *************************************************/
2762
2763 /* This function allows for user messages overriding the response code details
2764 by providing a suitable response code string at the start of the message
2765 user_msg. Check the message for starting with a response code and optionally an
2766 extended status code. If found, check that the first digit is valid, and if so,
2767 change the code pointer and length to use the replacement. An invalid code
2768 causes a panic log; in this case, if the log messages is the same as the user
2769 message, we must also adjust the value of the log message to show the code that
2770 is actually going to be used (the original one).
2771
2772 This function is global because it is called from receive.c as well as within
2773 this module.
2774
2775 Note that the code length returned includes the terminating whitespace
2776 character, which is always included in the regex match.
2777
2778 Arguments:
2779 code SMTP code, may involve extended status codes
2780 codelen length of smtp code; if > 4 there's an ESC
2781 msg message text
2782 log_msg optional log message, to be adjusted with the new SMTP code
2783 check_valid if true, verify the response code
2784
2785 Returns: nothing
2786 */
2787
2788 void
2789 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2790 BOOL check_valid)
2791 {
2792 int n;
2793 int ovector[3];
2794
2795 if (!msg || !*msg) return;
2796
2797 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2798 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
2799
2800 if (check_valid && (*msg)[0] != (*code)[0])
2801 {
2802 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2803 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2804 if (log_msg != NULL && *log_msg == *msg)
2805 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2806 }
2807 else
2808 {
2809 *code = *msg;
2810 *codelen = ovector[1]; /* Includes final space */
2811 }
2812 *msg += ovector[1]; /* Chop the code off the message */
2813 return;
2814 }
2815
2816
2817
2818
2819 /*************************************************
2820 * Handle an ACL failure *
2821 *************************************************/
2822
2823 /* This function is called when acl_check() fails. As well as calls from within
2824 this module, it is called from receive.c for an ACL after DATA. It sorts out
2825 logging the incident, and sets up the error response. A message containing
2826 newlines is turned into a multiline SMTP response, but for logging, only the
2827 first line is used.
2828
2829 There's a table of default permanent failure response codes to use in
2830 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2831 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2832 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2833 state, because there are broken clients that try VRFY before RCPT. A 5xx
2834 response should be given only when the address is positively known to be
2835 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2836 no explicit code, but if there is one we let it know best.
2837 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2838
2839 From Exim 4.63, it is possible to override the response code details by
2840 providing a suitable response code string at the start of the message provided
2841 in user_msg. The code's first digit is checked for validity.
2842
2843 Arguments:
2844 where where the ACL was called from
2845 rc the failure code
2846 user_msg a message that can be included in an SMTP response
2847 log_msg a message for logging
2848
2849 Returns: 0 in most cases
2850 2 if the failure code was FAIL_DROP, in which case the
2851 SMTP connection should be dropped (this value fits with the
2852 "done" variable in smtp_setup_msg() below)
2853 */
2854
2855 int
2856 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2857 {
2858 BOOL drop = rc == FAIL_DROP;
2859 int codelen = 3;
2860 uschar *smtp_code;
2861 uschar *lognl;
2862 uschar *sender_info = US"";
2863 uschar *what =
2864 #ifdef WITH_CONTENT_SCAN
2865 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
2866 #endif
2867 where == ACL_WHERE_PREDATA ? US"DATA" :
2868 where == ACL_WHERE_DATA ? US"after DATA" :
2869 #ifndef DISABLE_PRDR
2870 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
2871 #endif
2872 smtp_cmd_data ?
2873 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
2874 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
2875
2876 if (drop) rc = FAIL;
2877
2878 /* Set the default SMTP code, and allow a user message to change it. */
2879
2880 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2881 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2882 where != ACL_WHERE_VRFY);
2883
2884 /* We used to have sender_address here; however, there was a bug that was not
2885 updating sender_address after a rewrite during a verify. When this bug was
2886 fixed, sender_address at this point became the rewritten address. I'm not sure
2887 this is what should be logged, so I've changed to logging the unrewritten
2888 address to retain backward compatibility. */
2889
2890 #ifndef WITH_CONTENT_SCAN
2891 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2892 #else
2893 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2894 #endif
2895 {
2896 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2897 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2898 sender_host_authenticated ? US" A=" : US"",
2899 sender_host_authenticated ? sender_host_authenticated : US"",
2900 sender_host_authenticated && authenticated_id ? US":" : US"",
2901 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2902 );
2903 }
2904
2905 /* If there's been a sender verification failure with a specific message, and
2906 we have not sent a response about it yet, do so now, as a preliminary line for
2907 failures, but not defers. However, always log it for defer, and log it for fail
2908 unless the sender_verify_fail log selector has been turned off. */
2909
2910 if (sender_verified_failed != NULL &&
2911 !testflag(sender_verified_failed, af_sverify_told))
2912 {
2913 BOOL save_rcpt_in_progress = rcpt_in_progress;
2914 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2915
2916 setflag(sender_verified_failed, af_sverify_told);
2917
2918 if (rc != FAIL || LOGGING(sender_verify_fail))
2919 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2920 host_and_ident(TRUE),
2921 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2922 sender_verified_failed->address,
2923 (sender_verified_failed->message == NULL)? US"" :
2924 string_sprintf(": %s", sender_verified_failed->message));
2925
2926 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2927 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2928 testflag(sender_verified_failed, af_verify_pmfail)?
2929 "Postmaster verification failed while checking <%s>\n%s\n"
2930 "Several RFCs state that you are required to have a postmaster\n"
2931 "mailbox for each mail domain. This host does not accept mail\n"
2932 "from domains whose servers reject the postmaster address."
2933 :
2934 testflag(sender_verified_failed, af_verify_nsfail)?
2935 "Callback setup failed while verifying <%s>\n%s\n"
2936 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2937 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2938 "RFC requirements, and stops you from receiving standard bounce\n"
2939 "messages. This host does not accept mail from domains whose servers\n"
2940 "refuse bounces."
2941 :
2942 "Verification failed for <%s>\n%s",
2943 sender_verified_failed->address,
2944 sender_verified_failed->user_message));
2945
2946 rcpt_in_progress = save_rcpt_in_progress;
2947 }
2948
2949 /* Sort out text for logging */
2950
2951 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
2952 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
2953
2954 /* Send permanent failure response to the command, but the code used isn't
2955 always a 5xx one - see comments at the start of this function. If the original
2956 rc was FAIL_DROP we drop the connection and yield 2. */
2957
2958 if (rc == FAIL)
2959 smtp_respond(smtp_code, codelen, TRUE,
2960 user_msg ? user_msg : US"Administrative prohibition");
2961
2962 /* Send temporary failure response to the command. Don't give any details,
2963 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2964 verb, and for a header verify when smtp_return_error_details is set.
2965
2966 This conditional logic is all somewhat of a mess because of the odd
2967 interactions between temp_details and return_error_details. One day it should
2968 be re-implemented in a tidier fashion. */
2969
2970 else
2971 if (acl_temp_details && user_msg)
2972 {
2973 if ( smtp_return_error_details
2974 && sender_verified_failed
2975 && sender_verified_failed->message
2976 )
2977 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2978
2979 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2980 }
2981 else
2982 smtp_respond(smtp_code, codelen, TRUE,
2983 US"Temporary local problem - please try later");
2984
2985 /* Log the incident to the logs that are specified by log_reject_target
2986 (default main, reject). This can be empty to suppress logging of rejections. If
2987 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2988 is closing if required and return 2. */
2989
2990 if (log_reject_target != 0)
2991 {
2992 #ifdef SUPPORT_TLS
2993 uschar * tls = s_tlslog(NULL, NULL, NULL);
2994 if (!tls) tls = US"";
2995 #else
2996 uschar * tls = US"";
2997 #endif
2998 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
2999 log_reject_target, "%s%s%s %s%srejected %s%s",
3000 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3001 host_and_ident(TRUE),
3002 tls,
3003 sender_info,
3004 rc == FAIL ? US"" : US"temporarily ",
3005 what, log_msg);
3006 }
3007
3008 if (!drop) return 0;
3009
3010 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3011 smtp_get_connection_info());
3012
3013 /* Run the not-quit ACL, but without any custom messages. This should not be a
3014 problem, because we get here only if some other ACL has issued "drop", and
3015 in that case, *its* custom messages will have been used above. */
3016
3017 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3018 return 2;
3019 }
3020
3021
3022
3023
3024 /*************************************************
3025 * Handle SMTP exit when QUIT is not given *
3026 *************************************************/
3027
3028 /* This function provides a logging/statistics hook for when an SMTP connection
3029 is dropped on the floor or the other end goes away. It's a global function
3030 because it's called from receive.c as well as this module. As well as running
3031 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3032 response, either with a custom message from the ACL, or using a default. There
3033 is one case, however, when no message is output - after "drop". In that case,
3034 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3035 passed to this function.
3036
3037 In case things go wrong while processing this function, causing an error that
3038 may re-enter this funtion, there is a recursion check.
3039
3040 Arguments:
3041 reason What $smtp_notquit_reason will be set to in the ACL;
3042 if NULL, the ACL is not run
3043 code The error code to return as part of the response
3044 defaultrespond The default message if there's no user_msg
3045
3046 Returns: Nothing
3047 */
3048
3049 void
3050 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3051 {
3052 int rc;
3053 uschar *user_msg = NULL;
3054 uschar *log_msg = NULL;
3055
3056 /* Check for recursive acll */
3057
3058 if (smtp_exit_function_called)
3059 {
3060 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3061 reason);
3062 return;
3063 }
3064 smtp_exit_function_called = TRUE;
3065
3066 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3067
3068 if (acl_smtp_notquit && reason)
3069 {
3070 smtp_notquit_reason = reason;
3071 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3072 &log_msg)) == ERROR)
3073 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3074 log_msg);
3075 }
3076
3077 /* Write an SMTP response if we are expected to give one. As the default
3078 responses are all internal, they should always fit in the buffer, but code a
3079 warning, just in case. Note that string_vformat() still leaves a complete
3080 string, even if it is incomplete. */
3081
3082 if (code && defaultrespond)
3083 {
3084 if (user_msg)
3085 smtp_respond(code, 3, TRUE, user_msg);
3086 else
3087 {
3088 uschar buffer[128];
3089 va_list ap;
3090 va_start(ap, defaultrespond);
3091 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3092 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3093 smtp_printf("%s %s\r\n", code, buffer);
3094 va_end(ap);
3095 }
3096 mac_smtp_fflush();
3097 }
3098 }
3099
3100
3101
3102
3103 /*************************************************
3104 * Verify HELO argument *
3105 *************************************************/
3106
3107 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3108 matched. It is also called from ACL processing if verify = helo is used and
3109 verification was not previously tried (i.e. helo_try_verify_hosts was not
3110 matched). The result of its processing is to set helo_verified and
3111 helo_verify_failed. These variables should both be FALSE for this function to
3112 be called.
3113
3114 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3115 for IPv6 ::ffff: literals.
3116
3117 Argument: none
3118 Returns: TRUE if testing was completed;
3119 FALSE on a temporary failure
3120 */
3121
3122 BOOL
3123 smtp_verify_helo(void)
3124 {
3125 BOOL yield = TRUE;
3126
3127 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3128 sender_helo_name);
3129
3130 if (sender_helo_name == NULL)
3131 {
3132 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3133 }
3134
3135 /* Deal with the case of -bs without an IP address */
3136
3137 else if (sender_host_address == NULL)
3138 {
3139 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3140 helo_verified = TRUE;
3141 }
3142
3143 /* Deal with the more common case when there is a sending IP address */
3144
3145 else if (sender_helo_name[0] == '[')
3146 {
3147 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3148 Ustrlen(sender_host_address)) == 0;
3149
3150 #if HAVE_IPV6
3151 if (!helo_verified)
3152 {
3153 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3154 helo_verified = Ustrncmp(sender_helo_name + 1,
3155 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3156 }
3157 #endif
3158
3159 HDEBUG(D_receive)
3160 { if (helo_verified) debug_printf("matched host address\n"); }
3161 }
3162
3163 /* Do a reverse lookup if one hasn't already given a positive or negative
3164 response. If that fails, or the name doesn't match, try checking with a forward
3165 lookup. */
3166
3167 else
3168 {
3169 if (sender_host_name == NULL && !host_lookup_failed)
3170 yield = host_name_lookup() != DEFER;
3171
3172 /* If a host name is known, check it and all its aliases. */
3173
3174 if (sender_host_name)
3175 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3176 {
3177 sender_helo_dnssec = sender_host_dnssec;
3178 HDEBUG(D_receive) debug_printf("matched host name\n");
3179 }
3180 else
3181 {
3182 uschar **aliases = sender_host_aliases;
3183 while (*aliases)
3184 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3185 {
3186 sender_helo_dnssec = sender_host_dnssec;
3187 break;
3188 }
3189
3190 HDEBUG(D_receive) if (helo_verified)
3191 debug_printf("matched alias %s\n", *(--aliases));
3192 }
3193
3194 /* Final attempt: try a forward lookup of the helo name */
3195
3196 if (!helo_verified)
3197 {
3198 int rc;
3199 host_item h;
3200 dnssec_domains d;
3201 host_item *hh;
3202
3203 h.name = sender_helo_name;
3204 h.address = NULL;
3205 h.mx = MX_NONE;
3206 h.next = NULL;
3207 d.request = US"*";
3208 d.require = US"";
3209
3210 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3211 sender_helo_name);
3212 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3213 NULL, NULL, NULL, &d, NULL, NULL);
3214 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3215 for (hh = &h; hh; hh = hh->next)
3216 if (Ustrcmp(hh->address, sender_host_address) == 0)
3217 {
3218 helo_verified = TRUE;
3219 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3220 HDEBUG(D_receive)
3221 {
3222 debug_printf("IP address for %s matches calling address\n"
3223 "Forward DNS security status: %sverified\n",
3224 sender_helo_name, sender_helo_dnssec ? "" : "un");
3225 }
3226 break;
3227 }
3228 }
3229 }
3230
3231 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3232 return yield;
3233 }
3234
3235
3236
3237
3238 /*************************************************
3239 * Send user response message *
3240 *************************************************/
3241
3242 /* This function is passed a default response code and a user message. It calls
3243 smtp_message_code() to check and possibly modify the response code, and then
3244 calls smtp_respond() to transmit the response. I put this into a function
3245 just to avoid a lot of repetition.
3246
3247 Arguments:
3248 code the response code
3249 user_msg the user message
3250
3251 Returns: nothing
3252 */
3253
3254 static void
3255 smtp_user_msg(uschar *code, uschar *user_msg)
3256 {
3257 int len = 3;
3258 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3259 smtp_respond(code, len, TRUE, user_msg);
3260 }
3261
3262
3263
3264 static int
3265 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3266 {
3267 const uschar *set_id = NULL;
3268 int rc, i;
3269
3270 /* Run the checking code, passing the remainder of the command line as
3271 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3272 it as the only set numerical variable. The authenticator may set $auth<n>
3273 and also set other numeric variables. The $auth<n> variables are preferred
3274 nowadays; the numerical variables remain for backwards compatibility.
3275
3276 Afterwards, have a go at expanding the set_id string, even if
3277 authentication failed - for bad passwords it can be useful to log the
3278 userid. On success, require set_id to expand and exist, and put it in
3279 authenticated_id. Save this in permanent store, as the working store gets
3280 reset at HELO, RSET, etc. */
3281
3282 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3283 expand_nmax = 0;
3284 expand_nlength[0] = 0; /* $0 contains nothing */
3285
3286 rc = (au->info->servercode)(au, smtp_cmd_data);
3287 if (au->set_id) set_id = expand_string(au->set_id);
3288 expand_nmax = -1; /* Reset numeric variables */
3289 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3290
3291 /* The value of authenticated_id is stored in the spool file and printed in
3292 log lines. It must not contain binary zeros or newline characters. In
3293 normal use, it never will, but when playing around or testing, this error
3294 can (did) happen. To guard against this, ensure that the id contains only
3295 printing characters. */
3296
3297 if (set_id) set_id = string_printing(set_id);
3298
3299 /* For the non-OK cases, set up additional logging data if set_id
3300 is not empty. */
3301
3302 if (rc != OK)
3303 set_id = set_id && *set_id
3304 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3305
3306 /* Switch on the result */
3307
3308 switch(rc)
3309 {
3310 case OK:
3311 if (!au->set_id || set_id) /* Complete success */
3312 {
3313 if (set_id) authenticated_id = string_copy_malloc(set_id);
3314 sender_host_authenticated = au->name;
3315 authentication_failed = FALSE;
3316 authenticated_fail_id = NULL; /* Impossible to already be set? */
3317
3318 received_protocol =
3319 (sender_host_address ? protocols : protocols_local)
3320 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3321 *s = *ss = US"235 Authentication succeeded";
3322 authenticated_by = au;
3323 break;
3324 }
3325
3326 /* Authentication succeeded, but we failed to expand the set_id string.
3327 Treat this as a temporary error. */
3328
3329 auth_defer_msg = expand_string_message;
3330 /* Fall through */
3331
3332 case DEFER:
3333 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3334 *s = string_sprintf("435 Unable to authenticate at present%s",
3335 auth_defer_user_msg);
3336 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3337 set_id, auth_defer_msg);
3338 break;
3339
3340 case BAD64:
3341 *s = *ss = US"501 Invalid base64 data";
3342 break;
3343
3344 case CANCELLED:
3345 *s = *ss = US"501 Authentication cancelled";
3346 break;
3347
3348 case UNEXPECTED:
3349 *s = *ss = US"553 Initial data not expected";
3350 break;
3351
3352 case FAIL:
3353 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3354 *s = US"535 Incorrect authentication data";
3355 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3356 break;
3357
3358 default:
3359 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3360 *s = US"435 Internal error";
3361 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3362 "check", set_id, rc);
3363 break;
3364 }
3365
3366 return rc;
3367 }
3368
3369
3370
3371
3372
3373 static int
3374 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3375 {
3376 int rd;
3377 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3378 {
3379 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3380 *recipient);
3381 rd = Ustrlen(recipient) + 1;
3382 *recipient = rewrite_address_qualify(*recipient, TRUE);
3383 return rd;
3384 }
3385 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3386 smtp_cmd_data);
3387 log_write(L_smtp_syntax_error,
3388 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3389 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3390 return 0;
3391 }
3392
3393
3394
3395
3396 static void
3397 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3398 {
3399 HAD(SCH_QUIT);
3400 incomplete_transaction_log(US"QUIT");
3401 if (acl_smtp_quit)
3402 {
3403 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3404 if (rc == ERROR)
3405 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3406 *log_msgp);
3407 }
3408 if (*user_msgp)
3409 smtp_respond(US"221", 3, TRUE, *user_msgp);
3410 else
3411 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3412
3413 #ifdef SUPPORT_TLS
3414 tls_close(TRUE, TRUE);
3415 #endif
3416
3417 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3418 smtp_get_connection_info());
3419 }
3420
3421
3422 static void
3423 smtp_rset_handler(void)
3424 {
3425 HAD(SCH_RSET);
3426 incomplete_transaction_log(US"RSET");
3427 smtp_printf("250 Reset OK\r\n");
3428 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3429 }
3430
3431
3432
3433 /*************************************************
3434 * Initialize for SMTP incoming message *
3435 *************************************************/
3436
3437 /* This function conducts the initial dialogue at the start of an incoming SMTP
3438 message, and builds a list of recipients. However, if the incoming message
3439 is part of a batch (-bS option) a separate function is called since it would
3440 be messy having tests splattered about all over this function. This function
3441 therefore handles the case where interaction is occurring. The input and output
3442 files are set up in smtp_in and smtp_out.
3443
3444 The global recipients_list is set to point to a vector of recipient_item
3445 blocks, whose number is given by recipients_count. This is extended by the
3446 receive_add_recipient() function. The global variable sender_address is set to
3447 the sender's address. The yield is +1 if a message has been successfully
3448 started, 0 if a QUIT command was encountered or the connection was refused from
3449 the particular host, or -1 if the connection was lost.
3450
3451 Argument: none
3452
3453 Returns: > 0 message successfully started (reached DATA)
3454 = 0 QUIT read or end of file reached or call refused
3455 < 0 lost connection
3456 */
3457
3458 int
3459 smtp_setup_msg(void)
3460 {
3461 int done = 0;
3462 BOOL toomany = FALSE;
3463 BOOL discarded = FALSE;
3464 BOOL last_was_rej_mail = FALSE;
3465 BOOL last_was_rcpt = FALSE;
3466 void *reset_point = store_get(0);
3467
3468 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3469
3470 /* Reset for start of new message. We allow one RSET not to be counted as a
3471 nonmail command, for those MTAs that insist on sending it between every
3472 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3473 TLS between messages (an Exim client may do this if it has messages queued up
3474 for the host). Note: we do NOT reset AUTH at this point. */
3475
3476 smtp_reset(reset_point);
3477 message_ended = END_NOTSTARTED;
3478
3479 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3480
3481 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3482 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3483 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3484 #ifdef SUPPORT_TLS
3485 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3486 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3487 #endif
3488
3489 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3490
3491 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3492
3493 /* Batched SMTP is handled in a different function. */
3494
3495 if (smtp_batched_input) return smtp_setup_batch_msg();
3496
3497 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3498 value. The values are 2 larger than the required yield of the function. */
3499
3500 while (done <= 0)
3501 {
3502 const uschar **argv;
3503 uschar *etrn_command;
3504 uschar *etrn_serialize_key;
3505 uschar *errmess;
3506 uschar *log_msg, *smtp_code;
3507 uschar *user_msg = NULL;
3508 uschar *recipient = NULL;
3509 uschar *hello = NULL;
3510 uschar *s, *ss;
3511 BOOL was_rej_mail = FALSE;
3512 BOOL was_rcpt = FALSE;
3513 void (*oldsignal)(int);
3514 pid_t pid;
3515 int start, end, sender_domain, recipient_domain;
3516 int ptr, size, rc;
3517 int c;
3518 auth_instance *au;
3519 uschar *orcpt = NULL;
3520 int flags;
3521
3522 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3523 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3524 if ( tls_in.active >= 0
3525 && tls_in.peercert
3526 && tls_in.certificate_verified
3527 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3528 )
3529 {
3530 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3531 if ( acl_smtp_auth
3532 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3533 &user_msg, &log_msg)) != OK
3534 )
3535 {
3536 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3537 continue;
3538 }
3539
3540 for (au = auths; au; au = au->next)
3541 if (strcmpic(US"tls", au->driver_name) == 0)
3542 {
3543 smtp_cmd_data = NULL;
3544
3545 if (smtp_in_auth(au, &s, &ss) == OK)
3546 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3547 else
3548 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3549 break;
3550 }
3551 }
3552 #endif
3553
3554 switch(smtp_read_command(TRUE))
3555 {
3556 /* The AUTH command is not permitted to occur inside a transaction, and may
3557 occur successfully only once per connection. Actually, that isn't quite
3558 true. When TLS is started, all previous information about a connection must
3559 be discarded, so a new AUTH is permitted at that time.
3560
3561 AUTH may only be used when it has been advertised. However, it seems that
3562 there are clients that send AUTH when it hasn't been advertised, some of
3563 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3564 So there's a get-out that allows this to happen.
3565
3566 AUTH is initially labelled as a "nonmail command" so that one occurrence
3567 doesn't get counted. We change the label here so that multiple failing
3568 AUTHS will eventually hit the nonmail threshold. */
3569
3570 case AUTH_CMD:
3571 HAD(SCH_AUTH);
3572 authentication_failed = TRUE;
3573 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3574
3575 if (!auth_advertised && !allow_auth_unadvertised)
3576 {
3577 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3578 US"AUTH command used when not advertised");
3579 break;
3580 }
3581 if (sender_host_authenticated)
3582 {
3583 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3584 US"already authenticated");
3585 break;
3586 }
3587 if (sender_address)
3588 {
3589 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3590 US"not permitted in mail transaction");
3591 break;
3592 }
3593
3594 /* Check the ACL */
3595
3596 if ( acl_smtp_auth
3597 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3598 &user_msg, &log_msg)) != OK
3599 )
3600 {
3601 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3602 break;
3603 }
3604
3605 /* Find the name of the requested authentication mechanism. */
3606
3607 s = smtp_cmd_data;
3608 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3609 {
3610 if (!isalnum(c) && c != '-' && c != '_')
3611 {
3612 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3613 US"invalid character in authentication mechanism name");
3614 goto COMMAND_LOOP;
3615 }
3616 smtp_cmd_data++;
3617 }
3618
3619 /* If not at the end of the line, we must be at white space. Terminate the
3620 name and move the pointer on to any data that may be present. */
3621
3622 if (*smtp_cmd_data != 0)
3623 {
3624 *smtp_cmd_data++ = 0;
3625 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3626 }
3627
3628 /* Search for an authentication mechanism which is configured for use
3629 as a server and which has been advertised (unless, sigh, allow_auth_
3630 unadvertised is set). */
3631
3632 for (au = auths; au; au = au->next)
3633 if (strcmpic(s, au->public_name) == 0 && au->server &&
3634 (au->advertised || allow_auth_unadvertised))
3635 break;
3636
3637 if (au)
3638 {
3639 c = smtp_in_auth(au, &s, &ss);
3640
3641 smtp_printf("%s\r\n", s);
3642 if (c != OK)
3643 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3644 au->name, host_and_ident(FALSE), ss);
3645 }
3646 else
3647 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3648 string_sprintf("%s authentication mechanism not supported", s));
3649
3650 break; /* AUTH_CMD */
3651
3652 /* The HELO/EHLO commands are permitted to appear in the middle of a
3653 session as well as at the beginning. They have the effect of a reset in
3654 addition to their other functions. Their absence at the start cannot be
3655 taken to be an error.
3656
3657 RFC 2821 says:
3658
3659 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3660 or 502 failure replies MUST be returned as appropriate. The SMTP
3661 server MUST stay in the same state after transmitting these replies
3662 that it was in before the EHLO was received.
3663
3664 Therefore, we do not do the reset until after checking the command for
3665 acceptability. This change was made for Exim release 4.11. Previously
3666 it did the reset first. */
3667
3668 case HELO_CMD:
3669 HAD(SCH_HELO);
3670 hello = US"HELO";
3671 esmtp = FALSE;
3672 goto HELO_EHLO;
3673
3674 case EHLO_CMD:
3675 HAD(SCH_EHLO);
3676 hello = US"EHLO";
3677 esmtp = TRUE;
3678
3679 HELO_EHLO: /* Common code for HELO and EHLO */
3680 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3681 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3682
3683 /* Reject the HELO if its argument was invalid or non-existent. A
3684 successful check causes the argument to be saved in malloc store. */
3685
3686 if (!check_helo(smtp_cmd_data))
3687 {
3688 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3689
3690 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3691 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3692 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3693 string_printing(smtp_cmd_argument));
3694
3695 if (++synprot_error_count > smtp_max_synprot_errors)
3696 {
3697 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3698 "syntax or protocol errors (last command was \"%s\")",
3699 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3700 done = 1;
3701 }
3702
3703 break;
3704 }
3705
3706 /* If sender_host_unknown is true, we have got here via the -bs interface,
3707 not called from inetd. Otherwise, we are running an IP connection and the
3708 host address will be set. If the helo name is the primary name of this
3709 host and we haven't done a reverse lookup, force one now. If helo_required
3710 is set, ensure that the HELO name matches the actual host. If helo_verify
3711 is set, do the same check, but softly. */
3712
3713 if (!sender_host_unknown)
3714 {
3715 BOOL old_helo_verified = helo_verified;
3716 uschar *p = smtp_cmd_data;
3717
3718 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3719 *p = 0;
3720
3721 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3722 because otherwise the log can be confusing. */
3723
3724 if (sender_host_name == NULL &&
3725 (deliver_domain = sender_helo_name, /* set $domain */
3726 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3727 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3728 (void)host_name_lookup();
3729
3730 /* Rebuild the fullhost info to include the HELO name (and the real name
3731 if it was looked up.) */
3732
3733 host_build_sender_fullhost(); /* Rebuild */
3734 set_process_info("handling%s incoming connection from %s",
3735 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3736
3737 /* Verify if configured. This doesn't give much security, but it does
3738 make some people happy to be able to do it. If helo_required is set,
3739 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3740 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3741 now obsolescent, since the verification can now be requested selectively
3742 at ACL time. */
3743
3744 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
3745 if (helo_required || helo_verify)
3746 {
3747 BOOL tempfail = !smtp_verify_helo();
3748 if (!helo_verified)
3749 {
3750 if (helo_required)
3751 {
3752 smtp_printf("%d %s argument does not match calling host\r\n",
3753 tempfail? 451 : 550, hello);
3754 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3755 tempfail? "temporarily " : "",
3756 hello, sender_helo_name, host_and_ident(FALSE));
3757 helo_verified = old_helo_verified;
3758 break; /* End of HELO/EHLO processing */
3759 }
3760 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3761 "helo_try_verify_hosts\n", hello);
3762 }
3763 }
3764 }
3765
3766 #ifdef EXPERIMENTAL_SPF
3767 /* set up SPF context */
3768 spf_init(sender_helo_name, sender_host_address);
3769 #endif
3770
3771 /* Apply an ACL check if one is defined; afterwards, recheck
3772 synchronization in case the client started sending in a delay. */
3773
3774 if (acl_smtp_helo)
3775 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3776 &user_msg, &log_msg)) != OK)
3777 {
3778 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3779 sender_helo_name = NULL;
3780 host_build_sender_fullhost(); /* Rebuild */
3781 break;
3782 }
3783 else if (!check_sync()) goto SYNC_FAILURE;
3784
3785 /* Generate an OK reply. The default string includes the ident if present,
3786 and also the IP address if present. Reflecting back the ident is intended
3787 as a deterrent to mail forgers. For maximum efficiency, and also because
3788 some broken systems expect each response to be in a single packet, arrange
3789 that the entire reply is sent in one write(). */
3790
3791 auth_advertised = FALSE;
3792 pipelining_advertised = FALSE;
3793 #ifdef SUPPORT_TLS
3794 tls_advertised = FALSE;
3795 #endif
3796 dsn_advertised = FALSE;
3797 #ifdef SUPPORT_I18N
3798 smtputf8_advertised = FALSE;
3799 #endif
3800
3801 smtp_code = US"250 "; /* Default response code plus space*/
3802 if (user_msg == NULL)
3803 {
3804 s = string_sprintf("%.3s %s Hello %s%s%s",
3805 smtp_code,
3806 smtp_active_hostname,
3807 (sender_ident == NULL)? US"" : sender_ident,
3808 (sender_ident == NULL)? US"" : US" at ",
3809 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3810
3811 ptr = Ustrlen(s);
3812 size = ptr + 1;
3813
3814 if (sender_host_address != NULL)
3815 {
3816 s = string_catn(s, &size, &ptr, US" [", 2);
3817 s = string_cat (s, &size, &ptr, sender_host_address);
3818 s = string_catn(s, &size, &ptr, US"]", 1);
3819 }
3820 }
3821
3822 /* A user-supplied EHLO greeting may not contain more than one line. Note
3823 that the code returned by smtp_message_code() includes the terminating
3824 whitespace character. */
3825
3826 else
3827 {
3828 char *ss;
3829 int codelen = 4;
3830 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
3831 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3832 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3833 {
3834 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3835 "newlines: message truncated: %s", string_printing(s));
3836 *ss = 0;
3837 }
3838 ptr = Ustrlen(s);
3839 size = ptr + 1;
3840 }
3841
3842 s = string_catn(s, &size, &ptr, US"\r\n", 2);
3843
3844 /* If we received EHLO, we must create a multiline response which includes
3845 the functions supported. */
3846
3847 if (esmtp)
3848 {
3849 s[3] = '-';
3850
3851 /* I'm not entirely happy with this, as an MTA is supposed to check
3852 that it has enough room to accept a message of maximum size before
3853 it sends this. However, there seems little point in not sending it.
3854 The actual size check happens later at MAIL FROM time. By postponing it
3855 till then, VRFY and EXPN can be used after EHLO when space is short. */
3856
3857 if (thismessage_size_limit > 0)
3858 {
3859 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3860 thismessage_size_limit);
3861 s = string_cat(s, &size, &ptr, big_buffer);
3862 }
3863 else
3864 {
3865 s = string_catn(s, &size, &ptr, smtp_code, 3);
3866 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
3867 }
3868
3869 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3870 clean; if it has an 8-bit character in its hand, it just sends it. It
3871 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3872 However, some users want this option simply in order to stop MUAs
3873 mangling messages that contain top-bit-set characters. It is therefore
3874 provided as an option. */
3875
3876 if (accept_8bitmime)
3877 {
3878 s = string_catn(s, &size, &ptr, smtp_code, 3);
3879 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3880 }
3881
3882 /* Advertise DSN support if configured to do so. */
3883 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
3884 {
3885 s = string_catn(s, &size, &ptr, smtp_code, 3);
3886 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
3887 dsn_advertised = TRUE;
3888 }
3889
3890 /* Advertise ETRN if there's an ACL checking whether a host is
3891 permitted to issue it; a check is made when any host actually tries. */
3892
3893 if (acl_smtp_etrn != NULL)
3894 {
3895 s = string_catn(s, &size, &ptr, smtp_code, 3);
3896 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
3897 }
3898
3899 /* Advertise EXPN if there's an ACL checking whether a host is
3900 permitted to issue it; a check is made when any host actually tries. */
3901
3902 if (acl_smtp_expn != NULL)
3903 {
3904 s = string_catn(s, &size, &ptr, smtp_code, 3);
3905 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
3906 }
3907
3908 /* Exim is quite happy with pipelining, so let the other end know that
3909 it is safe to use it, unless advertising is disabled. */
3910
3911 if (pipelining_enable &&
3912 verify_check_host(&pipelining_advertise_hosts) == OK)
3913 {
3914 s = string_catn(s, &size, &ptr, smtp_code, 3);
3915 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3916 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3917 pipelining_advertised = TRUE;
3918 }
3919
3920
3921 /* If any server authentication mechanisms are configured, advertise
3922 them if the current host is in auth_advertise_hosts. The problem with
3923 advertising always is that some clients then require users to
3924 authenticate (and aren't configurable otherwise) even though it may not
3925 be necessary (e.g. if the host is in host_accept_relay).
3926
3927 RFC 2222 states that SASL mechanism names contain only upper case
3928 letters, so output the names in upper case, though we actually recognize
3929 them in either case in the AUTH command. */
3930
3931 if ( auths
3932 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3933 && !sender_host_authenticated
3934 #endif
3935 && verify_check_host(&auth_advertise_hosts) == OK
3936 )
3937 {
3938 auth_instance *au;
3939 BOOL first = TRUE;
3940 for (au = auths; au; au = au->next)
3941 if (au->server && (au->advertise_condition == NULL ||
3942 expand_check_condition(au->advertise_condition, au->name,
3943 US"authenticator")))
3944 {
3945 int saveptr;
3946 if (first)
3947 {
3948 s = string_catn(s, &size, &ptr, smtp_code, 3);
3949 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
3950 first = FALSE;
3951 auth_advertised = TRUE;
3952 }
3953 saveptr = ptr;
3954 s = string_catn(s, &size, &ptr, US" ", 1);
3955 s = string_cat (s, &size, &ptr, au->public_name);
3956 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3957 au->advertised = TRUE;
3958 }
3959 else
3960 au->advertised = FALSE;
3961
3962 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
3963 }
3964
3965 /* RFC 3030 CHUNKING */
3966
3967 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
3968 {
3969 s = string_catn(s, &size, &ptr, smtp_code, 3);
3970 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
3971 chunking_offered = TRUE;
3972 chunking_state = CHUNKING_OFFERED;
3973 }
3974
3975 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3976 if it has been included in the binary, and the host matches
3977 tls_advertise_hosts. We must *not* advertise if we are already in a
3978 secure connection. */
3979
3980 #ifdef SUPPORT_TLS
3981 if (tls_in.active < 0 &&
3982 verify_check_host(&tls_advertise_hosts) != FAIL)
3983 {
3984 s = string_catn(s, &size, &ptr, smtp_code, 3);
3985 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3986 tls_advertised = TRUE;
3987 }
3988 #endif
3989
3990 #ifndef DISABLE_PRDR
3991 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3992 if (prdr_enable)
3993 {
3994 s = string_catn(s, &size, &ptr, smtp_code, 3);
3995 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
3996 }
3997 #endif
3998
3999 #ifdef SUPPORT_I18N
4000 if ( accept_8bitmime
4001 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4002 {
4003 s = string_catn(s, &size, &ptr, smtp_code, 3);
4004 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
4005 smtputf8_advertised = TRUE;
4006 }
4007 #endif
4008
4009 /* Finish off the multiline reply with one that is always available. */
4010
4011 s = string_catn(s, &size, &ptr, smtp_code, 3);
4012 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
4013 }
4014
4015 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4016 has been seen. */
4017
4018 s[ptr] = 0;
4019
4020 #ifdef SUPPORT_TLS
4021 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
4022 #endif
4023
4024 {
4025 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
4026 }
4027 DEBUG(D_receive)
4028 {
4029 uschar *cr;
4030 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
4031 memmove(cr, cr + 1, (ptr--) - (cr - s));
4032 debug_printf("SMTP>> %s", s);
4033 }
4034 helo_seen = TRUE;
4035
4036 /* Reset the protocol and the state, abandoning any previous message. */
4037 received_protocol =
4038 (sender_host_address ? protocols : protocols_local)
4039 [ (esmtp
4040 ? pextend + (sender_host_authenticated ? pauthed : 0)
4041 : pnormal)
4042 + (tls_in.active >= 0 ? pcrpted : 0)
4043 ];
4044 smtp_reset(reset_point);
4045 toomany = FALSE;
4046 break; /* HELO/EHLO */
4047
4048
4049 /* The MAIL command requires an address as an operand. All we do
4050 here is to parse it for syntactic correctness. The form "<>" is
4051 a special case which converts into an empty string. The start/end
4052 pointers in the original are not used further for this address, as
4053 it is the canonical extracted address which is all that is kept. */
4054
4055 case MAIL_CMD:
4056 HAD(SCH_MAIL);
4057 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4058 was_rej_mail = TRUE; /* Reset if accepted */
4059 env_mail_type_t * mail_args; /* Sanity check & validate args */
4060
4061 if (helo_required && !helo_seen)
4062 {
4063 smtp_printf("503 HELO or EHLO required\r\n");
4064 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4065 "HELO/EHLO given", host_and_ident(FALSE));
4066 break;
4067 }
4068
4069 if (sender_address != NULL)
4070 {
4071 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4072 US"sender already given");
4073 break;
4074 }
4075
4076 if (smtp_cmd_data[0] == 0)
4077 {
4078 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4079 US"MAIL must have an address operand");
4080 break;
4081 }
4082
4083 /* Check to see if the limit for messages per connection would be
4084 exceeded by accepting further messages. */
4085
4086 if (smtp_accept_max_per_connection > 0 &&
4087 smtp_mailcmd_count > smtp_accept_max_per_connection)
4088 {
4089 smtp_printf("421 too many messages in this connection\r\n");
4090 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4091 "messages in one connection", host_and_ident(TRUE));
4092 break;