053b6aa26f8dfd337c9d68b583042b1f9588e803
[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 /* This is a dummy to identify the non-sync commands when not pipelining */
86
87 NON_SYNC_CMD_NON_PIPELINING,
88
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
99
100 BDAT_CMD,
101
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
105
106 AUTH_CMD,
107
108 /* I'm not sure about these, but I don't think they matter. */
109
110 QUIT_CMD, HELP_CMD,
111
112 #ifdef SUPPORT_PROXY
113 PROXY_FAIL_IGNORE_CMD,
114 #endif
115
116 /* These are specials that don't correspond to actual commands */
117
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
120
121
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
124
125 #define HAD(n) \
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
128
129
130 /*************************************************
131 * Local static variables *
132 *************************************************/
133
134 static auth_instance *authenticated_by;
135 static BOOL auth_advertised;
136 #ifdef SUPPORT_TLS
137 static BOOL tls_advertised;
138 #endif
139 static BOOL dsn_advertised;
140 static BOOL esmtp;
141 static BOOL helo_required = FALSE;
142 static BOOL helo_verify = FALSE;
143 static BOOL helo_seen;
144 static BOOL helo_accept_junk;
145 static BOOL count_nonmail;
146 static BOOL pipelining_advertised;
147 static BOOL rcpt_smtp_response_same;
148 static BOOL rcpt_in_progress;
149 static int nonmail_command_count;
150 static BOOL smtp_exit_function_called = 0;
151 #ifdef SUPPORT_I18N
152 static BOOL smtputf8_advertised;
153 #endif
154 static int synprot_error_count;
155 static int unknown_command_count;
156 static int sync_cmd_limit;
157 static int smtp_write_error = 0;
158
159 static uschar *rcpt_smtp_response;
160 static uschar *smtp_data_buffer;
161 static uschar *smtp_cmd_data;
162
163 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
164 final fields of all except AUTH are forced TRUE at the start of a new message
165 setup, to allow one of each between messages that is not counted as a nonmail
166 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
167 allow a new EHLO after starting up TLS.
168
169 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
170 counted. However, the flag is changed when AUTH is received, so that multiple
171 failing AUTHs will eventually hit the limit. After a successful AUTH, another
172 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
173 forced TRUE, to allow for the re-authentication that can happen at that point.
174
175 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
176 count of non-mail commands and possibly provoke an error.
177
178 tls_auth is a pseudo-command, never expected in input. It is activated
179 on TLS startup and looks for a tls authenticator. */
180
181 static smtp_cmd_list cmd_list[] = {
182 /* name len cmd has_arg is_mail_cmd */
183
184 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
185 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
186 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
187 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
188 #ifdef SUPPORT_TLS
189 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
190 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, TRUE },
191 #endif
192
193 /* If you change anything above here, also fix the definitions below. */
194
195 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
196 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
197 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
198 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
199 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
200 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
201 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
202 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
203 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
204 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
205 };
206
207 static smtp_cmd_list *cmd_list_end =
208 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
209
210 #define CMD_LIST_RSET 0
211 #define CMD_LIST_HELO 1
212 #define CMD_LIST_EHLO 2
213 #define CMD_LIST_AUTH 3
214 #define CMD_LIST_STARTTLS 4
215 #define CMD_LIST_TLS_AUTH 5
216
217 /* This list of names is used for performing the smtp_no_mail logging action.
218 It must be kept in step with the SCH_xxx enumerations. */
219
220 static uschar *smtp_names[] =
221 {
222 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
223 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
224 US"STARTTLS", US"VRFY" };
225
226 static uschar *protocols_local[] = {
227 US"local-smtp", /* HELO */
228 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
229 US"local-esmtp", /* EHLO */
230 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
231 US"local-esmtpa", /* EHLO->AUTH */
232 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
233 };
234 static uschar *protocols[] = {
235 US"smtp", /* HELO */
236 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
237 US"esmtp", /* EHLO */
238 US"esmtps", /* EHLO->STARTTLS->EHLO */
239 US"esmtpa", /* EHLO->AUTH */
240 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
241 };
242
243 #define pnormal 0
244 #define pextend 2
245 #define pcrpted 1 /* added to pextend or pnormal */
246 #define pauthed 2 /* added to pextend */
247
248 /* Sanity check and validate optional args to MAIL FROM: envelope */
249 enum {
250 ENV_MAIL_OPT_NULL,
251 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
252 #ifndef DISABLE_PRDR
253 ENV_MAIL_OPT_PRDR,
254 #endif
255 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
256 #ifdef SUPPORT_I18N
257 ENV_MAIL_OPT_UTF8,
258 #endif
259 };
260 typedef struct {
261 uschar * name; /* option requested during MAIL cmd */
262 int value; /* enum type */
263 BOOL need_value; /* TRUE requires value (name=value pair format)
264 FALSE is a singleton */
265 } env_mail_type_t;
266 static env_mail_type_t env_mail_type_list[] = {
267 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
268 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
269 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
270 #ifndef DISABLE_PRDR
271 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
272 #endif
273 { US"RET", ENV_MAIL_OPT_RET, TRUE },
274 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
275 #ifdef SUPPORT_I18N
276 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
277 #endif
278 /* keep this the last entry */
279 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
280 };
281
282 /* When reading SMTP from a remote host, we have to use our own versions of the
283 C input-reading functions, in order to be able to flush the SMTP output only
284 when about to read more data from the socket. This is the only way to get
285 optimal performance when the client is using pipelining. Flushing for every
286 command causes a separate packet and reply packet each time; saving all the
287 responses up (when pipelining) combines them into one packet and one response.
288
289 For simplicity, these functions are used for *all* SMTP input, not only when
290 receiving over a socket. However, after setting up a secure socket (SSL), input
291 is read via the OpenSSL library, and another set of functions is used instead
292 (see tls.c).
293
294 These functions are set in the receive_getc etc. variables and called with the
295 same interface as the C functions. However, since there can only ever be
296 one incoming SMTP call, we just use a single buffer and flags. There is no need
297 to implement a complicated private FILE-like structure.*/
298
299 static uschar *smtp_inbuffer;
300 static uschar *smtp_inptr;
301 static uschar *smtp_inend;
302 static int smtp_had_eof;
303 static int smtp_had_error;
304
305
306 /* forward declarations */
307 int bdat_ungetc(int ch);
308 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
309 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
310 static void smtp_quit_handler(uschar **, uschar **);
311 static void smtp_rset_handler(void);
312
313 /*************************************************
314 * Recheck synchronization *
315 *************************************************/
316
317 /* Synchronization checks can never be perfect because a packet may be on its
318 way but not arrived when the check is done. Such checks can in any case only be
319 done when TLS is not in use. Normally, the checks happen when commands are
320 read: Exim ensures that there is no more input in the input buffer. In normal
321 cases, the response to the command will be fast, and there is no further check.
322
323 However, for some commands an ACL is run, and that can include delays. In those
324 cases, it is useful to do another check on the input just before sending the
325 response. This also applies at the start of a connection. This function does
326 that check by means of the select() function, as long as the facility is not
327 disabled or inappropriate. A failure of select() is ignored.
328
329 When there is unwanted input, we read it so that it appears in the log of the
330 error.
331
332 Arguments: none
333 Returns: TRUE if all is well; FALSE if there is input pending
334 */
335
336 static BOOL
337 check_sync(void)
338 {
339 int fd, rc;
340 fd_set fds;
341 struct timeval tzero;
342
343 if (!smtp_enforce_sync || sender_host_address == NULL ||
344 sender_host_notsocket || tls_in.active >= 0)
345 return TRUE;
346
347 fd = fileno(smtp_in);
348 FD_ZERO(&fds);
349 FD_SET(fd, &fds);
350 tzero.tv_sec = 0;
351 tzero.tv_usec = 0;
352 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
353
354 if (rc <= 0) return TRUE; /* Not ready to read */
355 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
356 if (rc < 0) return TRUE; /* End of file or error */
357
358 smtp_ungetc(rc);
359 rc = smtp_inend - smtp_inptr;
360 if (rc > 150) rc = 150;
361 smtp_inptr[rc] = 0;
362 return FALSE;
363 }
364
365
366
367 /*************************************************
368 * Log incomplete transactions *
369 *************************************************/
370
371 /* This function is called after a transaction has been aborted by RSET, QUIT,
372 connection drops or other errors. It logs the envelope information received
373 so far in order to preserve address verification attempts.
374
375 Argument: string to indicate what aborted the transaction
376 Returns: nothing
377 */
378
379 static void
380 incomplete_transaction_log(uschar *what)
381 {
382 if (sender_address == NULL || /* No transaction in progress */
383 !LOGGING(smtp_incomplete_transaction))
384 return;
385
386 /* Build list of recipients for logging */
387
388 if (recipients_count > 0)
389 {
390 int i;
391 raw_recipients = store_get(recipients_count * sizeof(uschar *));
392 for (i = 0; i < recipients_count; i++)
393 raw_recipients[i] = recipients_list[i].address;
394 raw_recipients_count = recipients_count;
395 }
396
397 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
398 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
399 }
400
401
402
403
404 /*************************************************
405 * SMTP version of getc() *
406 *************************************************/
407
408 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
409 it flushes the output, and refills the buffer, with a timeout. The signal
410 handler is set appropriately by the calling function. This function is not used
411 after a connection has negotiated itself into an TLS/SSL state.
412
413 Arguments: lim Maximum amount to read/buffer
414 Returns: the next character or EOF
415 */
416
417 int
418 smtp_getc(unsigned lim)
419 {
420 if (smtp_inptr >= smtp_inend)
421 {
422 int rc, save_errno;
423 if (!smtp_out) return EOF;
424 fflush(smtp_out);
425 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
426
427 /* Limit amount read, so non-message data is not fed to DKIM */
428
429 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE, lim));
430 save_errno = errno;
431 alarm(0);
432 if (rc <= 0)
433 {
434 /* Must put the error text in fixed store, because this might be during
435 header reading, where it releases unused store above the header. */
436 if (rc < 0)
437 {
438 smtp_had_error = save_errno;
439 smtp_read_error = string_copy_malloc(
440 string_sprintf(" (error: %s)", strerror(save_errno)));
441 }
442 else smtp_had_eof = 1;
443 return EOF;
444 }
445 #ifndef DISABLE_DKIM
446 dkim_exim_verify_feed(smtp_inbuffer, rc);
447 #endif
448 smtp_inend = smtp_inbuffer + rc;
449 smtp_inptr = smtp_inbuffer;
450 }
451 return *smtp_inptr++;
452 }
453
454 void
455 smtp_get_cache(void)
456 {
457 #ifndef DISABLE_DKIM
458 int n = smtp_inend - smtp_inptr;
459 if (n > 0)
460 dkim_exim_verify_feed(smtp_inptr, n);
461 #endif
462 }
463
464
465 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
466 previous BDAT chunk and getting new ones when we run out. Uses the
467 underlying smtp_getc or tls_getc both for that and for getting the
468 (buffered) data byte. EOD signals (an expected) no further data.
469 ERR signals a protocol error, and EOF a closed input stream.
470
471 Called from read_bdat_smtp() in receive.c for the message body, but also
472 by the headers read loop in receive_msg(); manipulates chunking_state
473 to handle the BDAT command/response.
474 Placed here due to the correlation with the above smtp_getc(), which it wraps,
475 and also by the need to do smtp command/response handling.
476
477 Arguments: lim (ignored)
478 Returns: the next character or ERR, EOD or EOF
479 */
480
481 int
482 bdat_getc(unsigned lim)
483 {
484 uschar * user_msg = NULL;
485 uschar * log_msg;
486
487 for(;;)
488 {
489 if (chunking_data_left > 0)
490 return lwr_receive_getc(chunking_data_left--);
491
492 receive_getc = lwr_receive_getc;
493 receive_ungetc = lwr_receive_ungetc;
494 #ifndef DISABLE_DKIM
495 dkim_collect_input = FALSE;
496 #endif
497
498 /* Unless PIPELINING was offered, there should be no next command
499 until after we ack that chunk */
500
501 if (!pipelining_advertised && !check_sync())
502 {
503 incomplete_transaction_log(US"sync failure");
504 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
505 "(next input sent too soon: pipelining was not advertised): "
506 "rejected \"%s\" %s next input=\"%s\"",
507 smtp_cmd_buffer, host_and_ident(TRUE),
508 string_printing(smtp_inptr));
509 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
510 US"SMTP synchronization error");
511 goto repeat_until_rset;
512 }
513
514 /* If not the last, ack the received chunk. The last response is delayed
515 until after the data ACL decides on it */
516
517 if (chunking_state == CHUNKING_LAST)
518 {
519 #ifndef DISABLE_DKIM
520 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
521 #endif
522 return EOD;
523 }
524
525 smtp_printf("250 %u byte chunk received\r\n", chunking_datasize);
526 chunking_state = CHUNKING_OFFERED;
527 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
528
529 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
530 QUIT, RSET or NOOP but handling them seems obvious */
531
532 next_cmd:
533 switch(smtp_read_command(TRUE, 1))
534 {
535 default:
536 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
537 US"only BDAT permissible after non-LAST BDAT");
538
539 repeat_until_rset:
540 switch(smtp_read_command(TRUE, 1))
541 {
542 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
543 case EOF_CMD: return EOF;
544 case RSET_CMD: smtp_rset_handler(); return ERR;
545 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
546 US"only RSET accepted now") > 0)
547 return EOF;
548 goto repeat_until_rset;
549 }
550
551 case QUIT_CMD:
552 smtp_quit_handler(&user_msg, &log_msg);
553 /*FALLTHROUGH*/
554 case EOF_CMD:
555 return EOF;
556
557 case RSET_CMD:
558 smtp_rset_handler();
559 return ERR;
560
561 case NOOP_CMD:
562 HAD(SCH_NOOP);
563 smtp_printf("250 OK\r\n");
564 goto next_cmd;
565
566 case BDAT_CMD:
567 {
568 int n;
569
570 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
571 {
572 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
573 US"missing size for BDAT command");
574 return ERR;
575 }
576 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
577 ? CHUNKING_LAST : CHUNKING_ACTIVE;
578 chunking_data_left = chunking_datasize;
579 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
580 (int)chunking_state, chunking_data_left);
581
582 if (chunking_datasize == 0)
583 if (chunking_state == CHUNKING_LAST)
584 return EOD;
585 else
586 {
587 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
588 US"zero size for BDAT command");
589 goto repeat_until_rset;
590 }
591
592 receive_getc = bdat_getc;
593 receive_ungetc = bdat_ungetc;
594 #ifndef DISABLE_DKIM
595 dkim_collect_input = TRUE;
596 #endif
597 break; /* to top of main loop */
598 }
599 }
600 }
601 }
602
603 void
604 bdat_flush_data(void)
605 {
606 while (chunking_data_left > 0)
607 if (lwr_receive_getc(chunking_data_left--) < 0)
608 break;
609
610 receive_getc = lwr_receive_getc;
611 receive_ungetc = lwr_receive_ungetc;
612
613 if (chunking_state != CHUNKING_LAST)
614 {
615 chunking_state = CHUNKING_OFFERED;
616 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
617 }
618 }
619
620
621
622
623 /*************************************************
624 * SMTP version of ungetc() *
625 *************************************************/
626
627 /* Puts a character back in the input buffer. Only ever
628 called once.
629
630 Arguments:
631 ch the character
632
633 Returns: the character
634 */
635
636 int
637 smtp_ungetc(int ch)
638 {
639 *--smtp_inptr = ch;
640 return ch;
641 }
642
643
644 int
645 bdat_ungetc(int ch)
646 {
647 chunking_data_left++;
648 return lwr_receive_ungetc(ch);
649 }
650
651
652
653 /*************************************************
654 * SMTP version of feof() *
655 *************************************************/
656
657 /* Tests for a previous EOF
658
659 Arguments: none
660 Returns: non-zero if the eof flag is set
661 */
662
663 int
664 smtp_feof(void)
665 {
666 return smtp_had_eof;
667 }
668
669
670
671
672 /*************************************************
673 * SMTP version of ferror() *
674 *************************************************/
675
676 /* Tests for a previous read error, and returns with errno
677 restored to what it was when the error was detected.
678
679 Arguments: none
680 Returns: non-zero if the error flag is set
681 */
682
683 int
684 smtp_ferror(void)
685 {
686 errno = smtp_had_error;
687 return smtp_had_error;
688 }
689
690
691
692 /*************************************************
693 * Test for characters in the SMTP buffer *
694 *************************************************/
695
696 /* Used at the end of a message
697
698 Arguments: none
699 Returns: TRUE/FALSE
700 */
701
702 BOOL
703 smtp_buffered(void)
704 {
705 return smtp_inptr < smtp_inend;
706 }
707
708
709
710 /*************************************************
711 * Write formatted string to SMTP channel *
712 *************************************************/
713
714 /* This is a separate function so that we don't have to repeat everything for
715 TLS support or debugging. It is global so that the daemon and the
716 authentication functions can use it. It does not return any error indication,
717 because major problems such as dropped connections won't show up till an output
718 flush for non-TLS connections. The smtp_fflush() function is available for
719 checking that: for convenience, TLS output errors are remembered here so that
720 they are also picked up later by smtp_fflush().
721
722 Arguments:
723 format format string
724 ... optional arguments
725
726 Returns: nothing
727 */
728
729 void
730 smtp_printf(const char *format, ...)
731 {
732 va_list ap;
733
734 va_start(ap, format);
735 smtp_vprintf(format, ap);
736 va_end(ap);
737 }
738
739 /* This is split off so that verify.c:respond_printf() can, in effect, call
740 smtp_printf(), bearing in mind that in C a vararg function can't directly
741 call another vararg function, only a function which accepts a va_list. */
742
743 void
744 smtp_vprintf(const char *format, va_list ap)
745 {
746 BOOL yield;
747
748 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
749
750 DEBUG(D_receive)
751 {
752 void *reset_point = store_get(0);
753 uschar *msg_copy, *cr, *end;
754 msg_copy = string_copy(big_buffer);
755 end = msg_copy + Ustrlen(msg_copy);
756 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
757 memmove(cr, cr + 1, (end--) - cr);
758 debug_printf("SMTP>> %s", msg_copy);
759 store_reset(reset_point);
760 }
761
762 if (!yield)
763 {
764 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
765 smtp_closedown(US"Unexpected error");
766 exim_exit(EXIT_FAILURE);
767 }
768
769 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
770 have had the same. Note: this code is also present in smtp_respond(). It would
771 be tidier to have it only in one place, but when it was added, it was easier to
772 do it that way, so as not to have to mess with the code for the RCPT command,
773 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
774
775 if (rcpt_in_progress)
776 {
777 if (rcpt_smtp_response == NULL)
778 rcpt_smtp_response = string_copy(big_buffer);
779 else if (rcpt_smtp_response_same &&
780 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
781 rcpt_smtp_response_same = FALSE;
782 rcpt_in_progress = FALSE;
783 }
784
785 /* Now write the string */
786
787 #ifdef SUPPORT_TLS
788 if (tls_in.active >= 0)
789 {
790 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
791 smtp_write_error = -1;
792 }
793 else
794 #endif
795
796 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
797 }
798
799
800
801 /*************************************************
802 * Flush SMTP out and check for error *
803 *************************************************/
804
805 /* This function isn't currently used within Exim (it detects errors when it
806 tries to read the next SMTP input), but is available for use in local_scan().
807 For non-TLS connections, it flushes the output and checks for errors. For
808 TLS-connections, it checks for a previously-detected TLS write error.
809
810 Arguments: none
811 Returns: 0 for no error; -1 after an error
812 */
813
814 int
815 smtp_fflush(void)
816 {
817 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
818 return smtp_write_error;
819 }
820
821
822
823 /*************************************************
824 * SMTP command read timeout *
825 *************************************************/
826
827 /* Signal handler for timing out incoming SMTP commands. This attempts to
828 finish off tidily.
829
830 Argument: signal number (SIGALRM)
831 Returns: nothing
832 */
833
834 static void
835 command_timeout_handler(int sig)
836 {
837 sig = sig; /* Keep picky compilers happy */
838 log_write(L_lost_incoming_connection,
839 LOG_MAIN, "SMTP command timeout on%s connection from %s",
840 (tls_in.active >= 0)? " TLS" : "",
841 host_and_ident(FALSE));
842 if (smtp_batched_input)
843 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
844 smtp_notquit_exit(US"command-timeout", US"421",
845 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
846 exim_exit(EXIT_FAILURE);
847 }
848
849
850
851 /*************************************************
852 * SIGTERM received *
853 *************************************************/
854
855 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
856
857 Argument: signal number (SIGTERM)
858 Returns: nothing
859 */
860
861 static void
862 command_sigterm_handler(int sig)
863 {
864 sig = sig; /* Keep picky compilers happy */
865 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
866 if (smtp_batched_input)
867 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
868 smtp_notquit_exit(US"signal-exit", US"421",
869 US"%s: Service not available - closing connection", smtp_active_hostname);
870 exim_exit(EXIT_FAILURE);
871 }
872
873
874
875
876 #ifdef SUPPORT_PROXY
877 /*************************************************
878 * Restore socket timeout to previous value *
879 *************************************************/
880 /* If the previous value was successfully retrieved, restore
881 it before returning control to the non-proxy routines
882
883 Arguments: fd - File descriptor for input
884 get_ok - Successfully retrieved previous values
885 tvtmp - Time struct with previous values
886 vslen - Length of time struct
887 Returns: none
888 */
889 static void
890 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
891 {
892 if (get_ok == 0)
893 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
894 }
895
896 /*************************************************
897 * Check if host is required proxy host *
898 *************************************************/
899 /* The function determines if inbound host will be a regular smtp host
900 or if it is configured that it must use Proxy Protocol. A local
901 connection cannot.
902
903 Arguments: none
904 Returns: bool
905 */
906
907 static BOOL
908 check_proxy_protocol_host()
909 {
910 int rc;
911
912 if ( sender_host_address
913 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
914 sender_host_address, NULL)) == OK)
915 {
916 DEBUG(D_receive)
917 debug_printf("Detected proxy protocol configured host\n");
918 proxy_session = TRUE;
919 }
920 return proxy_session;
921 }
922
923
924 /*************************************************
925 * Setup host for proxy protocol *
926 *************************************************/
927 /* The function configures the connection based on a header from the
928 inbound host to use Proxy Protocol. The specification is very exact
929 so exit with an error if do not find the exact required pieces. This
930 includes an incorrect number of spaces separating args.
931
932 Arguments: none
933 Returns: Boolean success
934 */
935
936 static void
937 setup_proxy_protocol_host()
938 {
939 union {
940 struct {
941 uschar line[108];
942 } v1;
943 struct {
944 uschar sig[12];
945 uint8_t ver_cmd;
946 uint8_t fam;
947 uint16_t len;
948 union {
949 struct { /* TCP/UDP over IPv4, len = 12 */
950 uint32_t src_addr;
951 uint32_t dst_addr;
952 uint16_t src_port;
953 uint16_t dst_port;
954 } ip4;
955 struct { /* TCP/UDP over IPv6, len = 36 */
956 uint8_t src_addr[16];
957 uint8_t dst_addr[16];
958 uint16_t src_port;
959 uint16_t dst_port;
960 } ip6;
961 struct { /* AF_UNIX sockets, len = 216 */
962 uschar src_addr[108];
963 uschar dst_addr[108];
964 } unx;
965 } addr;
966 } v2;
967 } hdr;
968
969 /* Temp variables used in PPv2 address:port parsing */
970 uint16_t tmpport;
971 char tmpip[INET_ADDRSTRLEN];
972 struct sockaddr_in tmpaddr;
973 char tmpip6[INET6_ADDRSTRLEN];
974 struct sockaddr_in6 tmpaddr6;
975
976 int get_ok = 0;
977 int size, ret;
978 int fd = fileno(smtp_in);
979 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
980 uschar * iptype; /* To display debug info */
981 struct timeval tv;
982 struct timeval tvtmp;
983 socklen_t vslen = sizeof(struct timeval);
984 BOOL yield = FALSE;
985
986 /* Save current socket timeout values */
987 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
988
989 /* Proxy Protocol host must send header within a short time
990 (default 3 seconds) or it's considered invalid */
991 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
992 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
993 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
994 goto bad;
995
996 do
997 {
998 /* The inbound host was declared to be a Proxy Protocol host, so
999 don't do a PEEK into the data, actually slurp it up. */
1000 ret = recv(fd, &hdr, sizeof(hdr), 0);
1001 }
1002 while (ret == -1 && errno == EINTR);
1003
1004 if (ret == -1)
1005 goto proxyfail;
1006
1007 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1008 {
1009 uint8_t ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1010 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1011
1012 /* May 2014: haproxy combined the version and command into one byte to
1013 allow two full bytes for the length field in order to proxy SSL
1014 connections. SSL Proxy is not supported in this version of Exim, but
1015 must still separate values here. */
1016
1017 if (ver != 0x02)
1018 {
1019 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1020 goto proxyfail;
1021 }
1022 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
1023 /* The v2 header will always be 16 bytes per the spec. */
1024 size = 16 + ntohs(hdr.v2.len);
1025 if (ret < size)
1026 {
1027 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
1028 ret, size);
1029 goto proxyfail;
1030 }
1031 switch (cmd)
1032 {
1033 case 0x01: /* PROXY command */
1034 switch (hdr.v2.fam)
1035 {
1036 case 0x11: /* TCPv4 address type */
1037 iptype = US"IPv4";
1038 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1039 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1040 if (!string_is_ip_address(US tmpip, NULL))
1041 {
1042 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1043 goto proxyfail;
1044 }
1045 proxy_local_address = sender_host_address;
1046 sender_host_address = string_copy(US tmpip);
1047 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1048 proxy_local_port = sender_host_port;
1049 sender_host_port = tmpport;
1050 /* Save dest ip/port */
1051 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1052 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1053 if (!string_is_ip_address(US tmpip, NULL))
1054 {
1055 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1056 goto proxyfail;
1057 }
1058 proxy_external_address = string_copy(US tmpip);
1059 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1060 proxy_external_port = tmpport;
1061 goto done;
1062 case 0x21: /* TCPv6 address type */
1063 iptype = US"IPv6";
1064 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1065 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1066 if (!string_is_ip_address(US tmpip6, NULL))
1067 {
1068 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1069 goto proxyfail;
1070 }
1071 proxy_local_address = sender_host_address;
1072 sender_host_address = string_copy(US tmpip6);
1073 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1074 proxy_local_port = sender_host_port;
1075 sender_host_port = tmpport;
1076 /* Save dest ip/port */
1077 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1078 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1079 if (!string_is_ip_address(US tmpip6, NULL))
1080 {
1081 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1082 goto proxyfail;
1083 }
1084 proxy_external_address = string_copy(US tmpip6);
1085 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1086 proxy_external_port = tmpport;
1087 goto done;
1088 default:
1089 DEBUG(D_receive)
1090 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1091 hdr.v2.fam);
1092 goto proxyfail;
1093 }
1094 /* Unsupported protocol, keep local connection address */
1095 break;
1096 case 0x00: /* LOCAL command */
1097 /* Keep local connection address for LOCAL */
1098 iptype = US"local";
1099 break;
1100 default:
1101 DEBUG(D_receive)
1102 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1103 goto proxyfail;
1104 }
1105 }
1106 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1107 {
1108 uschar *p = string_copy(hdr.v1.line);
1109 uschar *end = memchr(p, '\r', ret - 1);
1110 uschar *sp; /* Utility variables follow */
1111 int tmp_port;
1112 char *endc;
1113
1114 if (!end || end[1] != '\n')
1115 {
1116 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1117 goto proxyfail;
1118 }
1119 *end = '\0'; /* Terminate the string */
1120 size = end + 2 - p; /* Skip header + CRLF */
1121 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1122 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %ld\n", ret - size);
1123 /* Step through the string looking for the required fields. Ensure
1124 strict adherence to required formatting, exit for any error. */
1125 p += 5;
1126 if (!isspace(*(p++)))
1127 {
1128 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1129 goto proxyfail;
1130 }
1131 if (!Ustrncmp(p, CCS"TCP4", 4))
1132 iptype = US"IPv4";
1133 else if (!Ustrncmp(p,CCS"TCP6", 4))
1134 iptype = US"IPv6";
1135 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1136 {
1137 iptype = US"Unknown";
1138 goto done;
1139 }
1140 else
1141 {
1142 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1143 goto proxyfail;
1144 }
1145
1146 p += Ustrlen(iptype);
1147 if (!isspace(*(p++)))
1148 {
1149 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1150 goto proxyfail;
1151 }
1152 /* Find the end of the arg */
1153 if ((sp = Ustrchr(p, ' ')) == NULL)
1154 {
1155 DEBUG(D_receive)
1156 debug_printf("Did not find proxied src %s\n", iptype);
1157 goto proxyfail;
1158 }
1159 *sp = '\0';
1160 if(!string_is_ip_address(p, NULL))
1161 {
1162 DEBUG(D_receive)
1163 debug_printf("Proxied src arg is not an %s address\n", iptype);
1164 goto proxyfail;
1165 }
1166 proxy_local_address = sender_host_address;
1167 sender_host_address = p;
1168 p = sp + 1;
1169 if ((sp = Ustrchr(p, ' ')) == NULL)
1170 {
1171 DEBUG(D_receive)
1172 debug_printf("Did not find proxy dest %s\n", iptype);
1173 goto proxyfail;
1174 }
1175 *sp = '\0';
1176 if(!string_is_ip_address(p, NULL))
1177 {
1178 DEBUG(D_receive)
1179 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1180 goto proxyfail;
1181 }
1182 proxy_external_address = p;
1183 p = sp + 1;
1184 if ((sp = Ustrchr(p, ' ')) == NULL)
1185 {
1186 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1187 goto proxyfail;
1188 }
1189 *sp = '\0';
1190 tmp_port = strtol(CCS p, &endc, 10);
1191 if (*endc || tmp_port == 0)
1192 {
1193 DEBUG(D_receive)
1194 debug_printf("Proxied src port '%s' not an integer\n", p);
1195 goto proxyfail;
1196 }
1197 proxy_local_port = sender_host_port;
1198 sender_host_port = tmp_port;
1199 p = sp + 1;
1200 if ((sp = Ustrchr(p, '\0')) == NULL)
1201 {
1202 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1203 goto proxyfail;
1204 }
1205 tmp_port = strtol(CCS p, &endc, 10);
1206 if (*endc || tmp_port == 0)
1207 {
1208 DEBUG(D_receive)
1209 debug_printf("Proxy dest port '%s' not an integer\n", p);
1210 goto proxyfail;
1211 }
1212 proxy_external_port = tmp_port;
1213 /* Already checked for /r /n above. Good V1 header received. */
1214 }
1215 else
1216 {
1217 /* Wrong protocol */
1218 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1219 goto proxyfail;
1220 }
1221
1222 done:
1223 DEBUG(D_receive)
1224 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1225 yield = proxy_session;
1226
1227 /* Don't flush any potential buffer contents. Any input on proxyfail
1228 should cause a synchronization failure */
1229
1230 proxyfail:
1231 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1232
1233 bad:
1234 if (yield)
1235 {
1236 sender_host_name = NULL;
1237 (void) host_name_lookup();
1238 host_build_sender_fullhost();
1239 }
1240 else
1241 {
1242 proxy_session_failed = TRUE;
1243 DEBUG(D_receive)
1244 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1245 }
1246
1247 return;
1248 }
1249 #endif
1250
1251 /*************************************************
1252 * Read one command line *
1253 *************************************************/
1254
1255 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1256 There are sites that don't do this, and in any case internal SMTP probably
1257 should check only for LF. Consequently, we check here for LF only. The line
1258 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1259 an unknown command. The command is read into the global smtp_cmd_buffer so that
1260 it is available via $smtp_command.
1261
1262 The character reading routine sets up a timeout for each block actually read
1263 from the input (which may contain more than one command). We set up a special
1264 signal handler that closes down the session on a timeout. Control does not
1265 return when it runs.
1266
1267 Arguments:
1268 check_sync if TRUE, check synchronization rules if global option is TRUE
1269 buffer_lim maximum to buffer in lower layer
1270
1271 Returns: a code identifying the command (enumerated above)
1272 */
1273
1274 static int
1275 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1276 {
1277 int c;
1278 int ptr = 0;
1279 smtp_cmd_list *p;
1280 BOOL hadnull = FALSE;
1281
1282 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1283
1284 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1285 {
1286 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1287 {
1288 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1289 return OTHER_CMD;
1290 }
1291 if (c == 0)
1292 {
1293 hadnull = TRUE;
1294 c = '?';
1295 }
1296 smtp_cmd_buffer[ptr++] = c;
1297 }
1298
1299 receive_linecount++; /* For BSMTP errors */
1300 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1301
1302 /* If hit end of file, return pseudo EOF command. Whether we have a
1303 part-line already read doesn't matter, since this is an error state. */
1304
1305 if (c == EOF) return EOF_CMD;
1306
1307 /* Remove any CR and white space at the end of the line, and terminate the
1308 string. */
1309
1310 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1311 smtp_cmd_buffer[ptr] = 0;
1312
1313 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1314
1315 /* NULLs are not allowed in SMTP commands */
1316
1317 if (hadnull) return BADCHAR_CMD;
1318
1319 /* Scan command list and return identity, having set the data pointer
1320 to the start of the actual data characters. Check for SMTP synchronization
1321 if required. */
1322
1323 for (p = cmd_list; p < cmd_list_end; p++)
1324 {
1325 #ifdef SUPPORT_PROXY
1326 /* Only allow QUIT command if Proxy Protocol parsing failed */
1327 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1328 continue;
1329 #endif
1330 if ( p->len
1331 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1332 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1333 || smtp_cmd_buffer[p->len] == 0
1334 || smtp_cmd_buffer[p->len] == ' '
1335 ) )
1336 {
1337 if (smtp_inptr < smtp_inend && /* Outstanding input */
1338 p->cmd < sync_cmd_limit && /* Command should sync */
1339 check_sync && /* Local flag set */
1340 smtp_enforce_sync && /* Global flag set */
1341 sender_host_address != NULL && /* Not local input */
1342 !sender_host_notsocket) /* Really is a socket */
1343 return BADSYN_CMD;
1344
1345 /* The variables $smtp_command and $smtp_command_argument point into the
1346 unmodified input buffer. A copy of the latter is taken for actual
1347 processing, so that it can be chopped up into separate parts if necessary,
1348 for example, when processing a MAIL command options such as SIZE that can
1349 follow the sender address. */
1350
1351 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1352 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1353 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1354 smtp_cmd_data = smtp_data_buffer;
1355
1356 /* Count non-mail commands from those hosts that are controlled in this
1357 way. The default is all hosts. We don't waste effort checking the list
1358 until we get a non-mail command, but then cache the result to save checking
1359 again. If there's a DEFER while checking the host, assume it's in the list.
1360
1361 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1362 start of each incoming message by fiddling with the value in the table. */
1363
1364 if (!p->is_mail_cmd)
1365 {
1366 if (count_nonmail == TRUE_UNSET) count_nonmail =
1367 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1368 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1369 return TOO_MANY_NONMAIL_CMD;
1370 }
1371
1372 /* If there is data for a command that does not expect it, generate the
1373 error here. */
1374
1375 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1376 }
1377 }
1378
1379 #ifdef SUPPORT_PROXY
1380 /* Only allow QUIT command if Proxy Protocol parsing failed */
1381 if (proxy_session && proxy_session_failed)
1382 return PROXY_FAIL_IGNORE_CMD;
1383 #endif
1384
1385 /* Enforce synchronization for unknown commands */
1386
1387 if (smtp_inptr < smtp_inend && /* Outstanding input */
1388 check_sync && /* Local flag set */
1389 smtp_enforce_sync && /* Global flag set */
1390 sender_host_address != NULL && /* Not local input */
1391 !sender_host_notsocket) /* Really is a socket */
1392 return BADSYN_CMD;
1393
1394 return OTHER_CMD;
1395 }
1396
1397
1398
1399 /*************************************************
1400 * Forced closedown of call *
1401 *************************************************/
1402
1403 /* This function is called from log.c when Exim is dying because of a serious
1404 disaster, and also from some other places. If an incoming non-batched SMTP
1405 channel is open, it swallows the rest of the incoming message if in the DATA
1406 phase, sends the reply string, and gives an error to all subsequent commands
1407 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1408 smtp_in.
1409
1410 Arguments:
1411 message SMTP reply string to send, excluding the code
1412
1413 Returns: nothing
1414 */
1415
1416 void
1417 smtp_closedown(uschar *message)
1418 {
1419 if (smtp_in == NULL || smtp_batched_input) return;
1420 receive_swallow_smtp();
1421 smtp_printf("421 %s\r\n", message);
1422
1423 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1424 {
1425 case EOF_CMD:
1426 return;
1427
1428 case QUIT_CMD:
1429 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1430 mac_smtp_fflush();
1431 return;
1432
1433 case RSET_CMD:
1434 smtp_printf("250 Reset OK\r\n");
1435 break;
1436
1437 default:
1438 smtp_printf("421 %s\r\n", message);
1439 break;
1440 }
1441 }
1442
1443
1444
1445
1446 /*************************************************
1447 * Set up connection info for logging *
1448 *************************************************/
1449
1450 /* This function is called when logging information about an SMTP connection.
1451 It sets up appropriate source information, depending on the type of connection.
1452 If sender_fullhost is NULL, we are at a very early stage of the connection;
1453 just use the IP address.
1454
1455 Argument: none
1456 Returns: a string describing the connection
1457 */
1458
1459 uschar *
1460 smtp_get_connection_info(void)
1461 {
1462 const uschar * hostname = sender_fullhost
1463 ? sender_fullhost : sender_host_address;
1464
1465 if (host_checking)
1466 return string_sprintf("SMTP connection from %s", hostname);
1467
1468 if (sender_host_unknown || sender_host_notsocket)
1469 return string_sprintf("SMTP connection from %s", sender_ident);
1470
1471 if (is_inetd)
1472 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1473
1474 if (LOGGING(incoming_interface) && interface_address != NULL)
1475 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1476 interface_address, interface_port);
1477
1478 return string_sprintf("SMTP connection from %s", hostname);
1479 }
1480
1481
1482
1483 #ifdef SUPPORT_TLS
1484 /* Append TLS-related information to a log line
1485
1486 Arguments:
1487 s String under construction: allocated string to extend, or NULL
1488 sizep Pointer to current allocation size (update on return), or NULL
1489 ptrp Pointer to index for new entries in string (update on return), or NULL
1490
1491 Returns: Allocated string or NULL
1492 */
1493 static uschar *
1494 s_tlslog(uschar * s, int * sizep, int * ptrp)
1495 {
1496 int size = sizep ? *sizep : 0;
1497 int ptr = ptrp ? *ptrp : 0;
1498
1499 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1500 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1501 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1502 s = string_append(s, &size, &ptr, 2, US" CV=",
1503 tls_in.certificate_verified? "yes":"no");
1504 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1505 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1506 string_printing(tls_in.peerdn), US"\"");
1507 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1508 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1509 string_printing(tls_in.sni), US"\"");
1510
1511 if (s)
1512 {
1513 s[ptr] = '\0';
1514 if (sizep) *sizep = size;
1515 if (ptrp) *ptrp = ptr;
1516 }
1517 return s;
1518 }
1519 #endif
1520
1521 /*************************************************
1522 * Log lack of MAIL if so configured *
1523 *************************************************/
1524
1525 /* This function is called when an SMTP session ends. If the log selector
1526 smtp_no_mail is set, write a log line giving some details of what has happened
1527 in the SMTP session.
1528
1529 Arguments: none
1530 Returns: nothing
1531 */
1532
1533 void
1534 smtp_log_no_mail(void)
1535 {
1536 int size, ptr, i;
1537 uschar *s, *sep;
1538
1539 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1540 return;
1541
1542 s = NULL;
1543 size = ptr = 0;
1544
1545 if (sender_host_authenticated != NULL)
1546 {
1547 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1548 if (authenticated_id != NULL)
1549 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1550 }
1551
1552 #ifdef SUPPORT_TLS
1553 s = s_tlslog(s, &size, &ptr);
1554 #endif
1555
1556 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1557 US" C=..." : US" C=";
1558 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1559 {
1560 if (smtp_connection_had[i] != SCH_NONE)
1561 {
1562 s = string_append(s, &size, &ptr, 2, sep,
1563 smtp_names[smtp_connection_had[i]]);
1564 sep = US",";
1565 }
1566 }
1567
1568 for (i = 0; i < smtp_ch_index; i++)
1569 {
1570 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1571 sep = US",";
1572 }
1573
1574 if (s != NULL) s[ptr] = 0; else s = US"";
1575 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1576 host_and_ident(FALSE),
1577 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1578 s);
1579 }
1580
1581
1582
1583 /*************************************************
1584 * Check HELO line and set sender_helo_name *
1585 *************************************************/
1586
1587 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1588 the domain name of the sending host, or an ip literal in square brackets. The
1589 argument is placed in sender_helo_name, which is in malloc store, because it
1590 must persist over multiple incoming messages. If helo_accept_junk is set, this
1591 host is permitted to send any old junk (needed for some broken hosts).
1592 Otherwise, helo_allow_chars can be used for rogue characters in general
1593 (typically people want to let in underscores).
1594
1595 Argument:
1596 s the data portion of the line (already past any white space)
1597
1598 Returns: TRUE or FALSE
1599 */
1600
1601 static BOOL
1602 check_helo(uschar *s)
1603 {
1604 uschar *start = s;
1605 uschar *end = s + Ustrlen(s);
1606 BOOL yield = helo_accept_junk;
1607
1608 /* Discard any previous helo name */
1609
1610 if (sender_helo_name != NULL)
1611 {
1612 store_free(sender_helo_name);
1613 sender_helo_name = NULL;
1614 }
1615
1616 /* Skip tests if junk is permitted. */
1617
1618 if (!yield)
1619 {
1620 /* Allow the new standard form for IPv6 address literals, namely,
1621 [IPv6:....], and because someone is bound to use it, allow an equivalent
1622 IPv4 form. Allow plain addresses as well. */
1623
1624 if (*s == '[')
1625 {
1626 if (end[-1] == ']')
1627 {
1628 end[-1] = 0;
1629 if (strncmpic(s, US"[IPv6:", 6) == 0)
1630 yield = (string_is_ip_address(s+6, NULL) == 6);
1631 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1632 yield = (string_is_ip_address(s+6, NULL) == 4);
1633 else
1634 yield = (string_is_ip_address(s+1, NULL) != 0);
1635 end[-1] = ']';
1636 }
1637 }
1638
1639 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1640 that have been configured (usually underscore - sigh). */
1641
1642 else if (*s != 0)
1643 {
1644 yield = TRUE;
1645 while (*s != 0)
1646 {
1647 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1648 Ustrchr(helo_allow_chars, *s) == NULL)
1649 {
1650 yield = FALSE;
1651 break;
1652 }
1653 s++;
1654 }
1655 }
1656 }
1657
1658 /* Save argument if OK */
1659
1660 if (yield) sender_helo_name = string_copy_malloc(start);
1661 return yield;
1662 }
1663
1664
1665
1666
1667
1668 /*************************************************
1669 * Extract SMTP command option *
1670 *************************************************/
1671
1672 /* This function picks the next option setting off the end of smtp_cmd_data. It
1673 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1674 things that can appear there.
1675
1676 Arguments:
1677 name point this at the name
1678 value point this at the data string
1679
1680 Returns: TRUE if found an option
1681 */
1682
1683 static BOOL
1684 extract_option(uschar **name, uschar **value)
1685 {
1686 uschar *n;
1687 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1688 while (isspace(*v)) v--;
1689 v[1] = 0;
1690 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1691 {
1692 /* Take care to not stop at a space embedded in a quoted local-part */
1693
1694 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1695 v--;
1696 }
1697
1698 n = v;
1699 if (*v == '=')
1700 {
1701 while(isalpha(n[-1])) n--;
1702 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1703 if (!isspace(n[-1])) return FALSE;
1704 n[-1] = 0;
1705 }
1706 else
1707 {
1708 n++;
1709 if (v == smtp_cmd_data) return FALSE;
1710 }
1711 *v++ = 0;
1712 *name = n;
1713 *value = v;
1714 return TRUE;
1715 }
1716
1717
1718
1719
1720
1721 /*************************************************
1722 * Reset for new message *
1723 *************************************************/
1724
1725 /* This function is called whenever the SMTP session is reset from
1726 within either of the setup functions.
1727
1728 Argument: the stacking pool storage reset point
1729 Returns: nothing
1730 */
1731
1732 static void
1733 smtp_reset(void *reset_point)
1734 {
1735 store_reset(reset_point);
1736 recipients_list = NULL;
1737 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1738 raw_recipients_count = recipients_count = recipients_list_max = 0;
1739 cancel_cutthrough_connection("smtp reset");
1740 message_linecount = 0;
1741 message_size = -1;
1742 acl_added_headers = NULL;
1743 acl_removed_headers = NULL;
1744 queue_only_policy = FALSE;
1745 rcpt_smtp_response = NULL;
1746 rcpt_smtp_response_same = TRUE;
1747 rcpt_in_progress = FALSE;
1748 deliver_freeze = FALSE; /* Can be set by ACL */
1749 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1750 fake_response = OK; /* Can be set by ACL */
1751 #ifdef WITH_CONTENT_SCAN
1752 no_mbox_unspool = FALSE; /* Can be set by ACL */
1753 #endif
1754 submission_mode = FALSE; /* Can be set by ACL */
1755 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1756 active_local_from_check = local_from_check; /* Can be set by ACL */
1757 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1758 sender_address = NULL;
1759 submission_name = NULL; /* Can be set by ACL */
1760 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1761 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1762 sender_verified_list = NULL; /* No senders verified */
1763 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1764 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1765
1766 authenticated_sender = NULL;
1767 #ifdef EXPERIMENTAL_BRIGHTMAIL
1768 bmi_run = 0;
1769 bmi_verdicts = NULL;
1770 #endif
1771 #ifndef DISABLE_DKIM
1772 dkim_signers = NULL;
1773 dkim_disable_verify = FALSE;
1774 dkim_collect_input = FALSE;
1775 #endif
1776 dsn_ret = 0;
1777 dsn_envid = NULL;
1778 #ifndef DISABLE_PRDR
1779 prdr_requested = FALSE;
1780 #endif
1781 #ifdef EXPERIMENTAL_SPF
1782 spf_header_comment = NULL;
1783 spf_received = NULL;
1784 spf_result = NULL;
1785 spf_smtp_comment = NULL;
1786 #endif
1787 #ifdef SUPPORT_I18N
1788 message_smtputf8 = FALSE;
1789 #endif
1790 body_linecount = body_zerocount = 0;
1791
1792 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1793 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1794 /* Note that ratelimiters_conn persists across resets. */
1795
1796 /* Reset message ACL variables */
1797
1798 acl_var_m = NULL;
1799
1800 /* The message body variables use malloc store. They may be set if this is
1801 not the first message in an SMTP session and the previous message caused them
1802 to be referenced in an ACL. */
1803
1804 if (message_body != NULL)
1805 {
1806 store_free(message_body);
1807 message_body = NULL;
1808 }
1809
1810 if (message_body_end != NULL)
1811 {
1812 store_free(message_body_end);
1813 message_body_end = NULL;
1814 }
1815
1816 /* Warning log messages are also saved in malloc store. They are saved to avoid
1817 repetition in the same message, but it seems right to repeat them for different
1818 messages. */
1819
1820 while (acl_warn_logged != NULL)
1821 {
1822 string_item *this = acl_warn_logged;
1823 acl_warn_logged = acl_warn_logged->next;
1824 store_free(this);
1825 }
1826 }
1827
1828
1829
1830
1831
1832 /*************************************************
1833 * Initialize for incoming batched SMTP message *
1834 *************************************************/
1835
1836 /* This function is called from smtp_setup_msg() in the case when
1837 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1838 of messages in one file with SMTP commands between them. All errors must be
1839 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1840 relevant. After an error on a sender, or an invalid recipient, the remainder
1841 of the message is skipped. The value of received_protocol is already set.
1842
1843 Argument: none
1844 Returns: > 0 message successfully started (reached DATA)
1845 = 0 QUIT read or end of file reached
1846 < 0 should not occur
1847 */
1848
1849 static int
1850 smtp_setup_batch_msg(void)
1851 {
1852 int done = 0;
1853 void *reset_point = store_get(0);
1854
1855 /* Save the line count at the start of each transaction - single commands
1856 like HELO and RSET count as whole transactions. */
1857
1858 bsmtp_transaction_linecount = receive_linecount;
1859
1860 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1861
1862 smtp_reset(reset_point); /* Reset for start of message */
1863
1864 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1865 value. The values are 2 larger than the required yield of the function. */
1866
1867 while (done <= 0)
1868 {
1869 uschar *errmess;
1870 uschar *recipient = NULL;
1871 int start, end, sender_domain, recipient_domain;
1872
1873 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1874 {
1875 /* The HELO/EHLO commands set sender_address_helo if they have
1876 valid data; otherwise they are ignored, except that they do
1877 a reset of the state. */
1878
1879 case HELO_CMD:
1880 case EHLO_CMD:
1881
1882 check_helo(smtp_cmd_data);
1883 /* Fall through */
1884
1885 case RSET_CMD:
1886 smtp_reset(reset_point);
1887 bsmtp_transaction_linecount = receive_linecount;
1888 break;
1889
1890
1891 /* The MAIL FROM command requires an address as an operand. All we
1892 do here is to parse it for syntactic correctness. The form "<>" is
1893 a special case which converts into an empty string. The start/end
1894 pointers in the original are not used further for this address, as
1895 it is the canonical extracted address which is all that is kept. */
1896
1897 case MAIL_CMD:
1898 smtp_mailcmd_count++; /* Count for no-mail log */
1899 if (sender_address != NULL)
1900 /* The function moan_smtp_batch() does not return. */
1901 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1902
1903 if (smtp_cmd_data[0] == 0)
1904 /* The function moan_smtp_batch() does not return. */
1905 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1906
1907 /* Reset to start of message */
1908
1909 smtp_reset(reset_point);
1910
1911 /* Apply SMTP rewrite */
1912
1913 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1914 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1915 US"", global_rewrite_rules) : smtp_cmd_data;
1916
1917 /* Extract the address; the TRUE flag allows <> as valid */
1918
1919 raw_sender =
1920 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1921 TRUE);
1922
1923 if (raw_sender == NULL)
1924 /* The function moan_smtp_batch() does not return. */
1925 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1926
1927 sender_address = string_copy(raw_sender);
1928
1929 /* Qualify unqualified sender addresses if permitted to do so. */
1930
1931 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1932 {
1933 if (allow_unqualified_sender)
1934 {
1935 sender_address = rewrite_address_qualify(sender_address, FALSE);
1936 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1937 "and rewritten\n", raw_sender);
1938 }
1939 /* The function moan_smtp_batch() does not return. */
1940 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1941 "a domain");
1942 }
1943 break;
1944
1945
1946 /* The RCPT TO command requires an address as an operand. All we do
1947 here is to parse it for syntactic correctness. There may be any number
1948 of RCPT TO commands, specifying multiple senders. We build them all into
1949 a data structure that is in argc/argv format. The start/end values
1950 given by parse_extract_address are not used, as we keep only the
1951 extracted address. */
1952
1953 case RCPT_CMD:
1954 if (sender_address == NULL)
1955 /* The function moan_smtp_batch() does not return. */
1956 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1957
1958 if (smtp_cmd_data[0] == 0)
1959 /* The function moan_smtp_batch() does not return. */
1960 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1961
1962 /* Check maximum number allowed */
1963
1964 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1965 /* The function moan_smtp_batch() does not return. */
1966 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1967 recipients_max_reject? "552": "452");
1968
1969 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1970 recipient address */
1971
1972 recipient = rewrite_existflags & rewrite_smtp
1973 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1974 global_rewrite_rules)
1975 : smtp_cmd_data;
1976
1977 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1978 &recipient_domain, FALSE);
1979
1980 if (!recipient)
1981 /* The function moan_smtp_batch() does not return. */
1982 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1983
1984 /* If the recipient address is unqualified, qualify it if permitted. Then
1985 add it to the list of recipients. */
1986
1987 if (recipient_domain == 0)
1988 {
1989 if (allow_unqualified_recipient)
1990 {
1991 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1992 recipient);
1993 recipient = rewrite_address_qualify(recipient, TRUE);
1994 }
1995 /* The function moan_smtp_batch() does not return. */
1996 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1997 "a domain");
1998 }
1999 receive_add_recipient(recipient, -1);
2000 break;
2001
2002
2003 /* The DATA command is legal only if it follows successful MAIL FROM
2004 and RCPT TO commands. This function is complete when a valid DATA
2005 command is encountered. */
2006
2007 case DATA_CMD:
2008 if (sender_address == NULL || recipients_count <= 0)
2009 {
2010 /* The function moan_smtp_batch() does not return. */
2011 if (sender_address == NULL)
2012 moan_smtp_batch(smtp_cmd_buffer,
2013 "503 MAIL FROM:<sender> command must precede DATA");
2014 else
2015 moan_smtp_batch(smtp_cmd_buffer,
2016 "503 RCPT TO:<recipient> must precede DATA");
2017 }
2018 else
2019 {
2020 done = 3; /* DATA successfully achieved */
2021 message_ended = END_NOTENDED; /* Indicate in middle of message */
2022 }
2023 break;
2024
2025
2026 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2027
2028 case VRFY_CMD:
2029 case EXPN_CMD:
2030 case HELP_CMD:
2031 case NOOP_CMD:
2032 case ETRN_CMD:
2033 bsmtp_transaction_linecount = receive_linecount;
2034 break;
2035
2036
2037 case EOF_CMD:
2038 case QUIT_CMD:
2039 done = 2;
2040 break;
2041
2042
2043 case BADARG_CMD:
2044 /* The function moan_smtp_batch() does not return. */
2045 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2046 break;
2047
2048
2049 case BADCHAR_CMD:
2050 /* The function moan_smtp_batch() does not return. */
2051 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2052 break;
2053
2054
2055 default:
2056 /* The function moan_smtp_batch() does not return. */
2057 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2058 break;
2059 }
2060 }
2061
2062 return done - 2; /* Convert yield values */
2063 }
2064
2065
2066
2067
2068 /*************************************************
2069 * Start an SMTP session *
2070 *************************************************/
2071
2072 /* This function is called at the start of an SMTP session. Thereafter,
2073 smtp_setup_msg() is called to initiate each separate message. This
2074 function does host-specific testing, and outputs the banner line.
2075
2076 Arguments: none
2077 Returns: FALSE if the session can not continue; something has
2078 gone wrong, or the connection to the host is blocked
2079 */
2080
2081 BOOL
2082 smtp_start_session(void)
2083 {
2084 int size = 256;
2085 int ptr, esclen;
2086 uschar *user_msg, *log_msg;
2087 uschar *code, *esc;
2088 uschar *p, *s, *ss;
2089
2090 smtp_connection_start = time(NULL);
2091 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2092 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2093 smtp_ch_index = 0;
2094
2095 /* Default values for certain variables */
2096
2097 helo_seen = esmtp = helo_accept_junk = FALSE;
2098 smtp_mailcmd_count = 0;
2099 count_nonmail = TRUE_UNSET;
2100 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2101 smtp_delay_mail = smtp_rlm_base;
2102 auth_advertised = FALSE;
2103 pipelining_advertised = FALSE;
2104 pipelining_enable = TRUE;
2105 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2106 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2107
2108 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2109 authentication settings from -oMaa to remain in force. */
2110
2111 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2112 authenticated_by = NULL;
2113
2114 #ifdef SUPPORT_TLS
2115 tls_in.cipher = tls_in.peerdn = NULL;
2116 tls_in.ourcert = tls_in.peercert = NULL;
2117 tls_in.sni = NULL;
2118 tls_in.ocsp = OCSP_NOT_REQ;
2119 tls_advertised = FALSE;
2120 #endif
2121 dsn_advertised = FALSE;
2122 #ifdef SUPPORT_I18N
2123 smtputf8_advertised = FALSE;
2124 #endif
2125
2126 /* Reset ACL connection variables */
2127
2128 acl_var_c = NULL;
2129
2130 /* Allow for trailing 0 in the command and data buffers. */
2131
2132 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2133 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2134 "malloc() failed for SMTP command buffer");
2135
2136 smtp_cmd_buffer[0] = 0;
2137 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2138
2139 /* For batched input, the protocol setting can be overridden from the
2140 command line by a trusted caller. */
2141
2142 if (smtp_batched_input)
2143 {
2144 if (!received_protocol) received_protocol = US"local-bsmtp";
2145 }
2146
2147 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2148 reset later if any of EHLO/AUTH/STARTTLS are received. */
2149
2150 else
2151 received_protocol =
2152 (sender_host_address ? protocols : protocols_local) [pnormal];
2153
2154 /* Set up the buffer for inputting using direct read() calls, and arrange to
2155 call the local functions instead of the standard C ones. */
2156
2157 if (!(smtp_inbuffer = (uschar *)malloc(IN_BUFFER_SIZE)))
2158 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2159
2160 receive_getc = smtp_getc;
2161 receive_get_cache = smtp_get_cache;
2162 receive_ungetc = smtp_ungetc;
2163 receive_feof = smtp_feof;
2164 receive_ferror = smtp_ferror;
2165 receive_smtp_buffered = smtp_buffered;
2166 smtp_inptr = smtp_inend = smtp_inbuffer;
2167 smtp_had_eof = smtp_had_error = 0;
2168
2169 /* Set up the message size limit; this may be host-specific */
2170
2171 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2172 if (expand_string_message != NULL)
2173 {
2174 if (thismessage_size_limit == -1)
2175 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2176 "%s", expand_string_message);
2177 else
2178 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2179 "%s", expand_string_message);
2180 smtp_closedown(US"Temporary local problem - please try later");
2181 return FALSE;
2182 }
2183
2184 /* When a message is input locally via the -bs or -bS options, sender_host_
2185 unknown is set unless -oMa was used to force an IP address, in which case it
2186 is checked like a real remote connection. When -bs is used from inetd, this
2187 flag is not set, causing the sending host to be checked. The code that deals
2188 with IP source routing (if configured) is never required for -bs or -bS and
2189 the flag sender_host_notsocket is used to suppress it.
2190
2191 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2192 reserve for certain hosts and/or networks. */
2193
2194 if (!sender_host_unknown)
2195 {
2196 int rc;
2197 BOOL reserved_host = FALSE;
2198
2199 /* Look up IP options (source routing info) on the socket if this is not an
2200 -oMa "host", and if any are found, log them and drop the connection.
2201
2202 Linux (and others now, see below) is different to everyone else, so there
2203 has to be some conditional compilation here. Versions of Linux before 2.1.15
2204 used a structure whose name was "options". Somebody finally realized that
2205 this name was silly, and it got changed to "ip_options". I use the
2206 newer name here, but there is a fudge in the script that sets up os.h
2207 to define a macro in older Linux systems.
2208
2209 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2210 glibc 2, which has chosen ip_opts for the structure name. This is now
2211 really a glibc thing rather than a Linux thing, so the condition name
2212 has been changed to reflect this. It is relevant also to GNU/Hurd.
2213
2214 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2215 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2216 a special macro defined in the os.h file.
2217
2218 Some DGUX versions on older hardware appear not to support IP options at
2219 all, so there is now a general macro which can be set to cut out this
2220 support altogether.
2221
2222 How to do this properly in IPv6 is not yet known. */
2223
2224 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2225
2226 #ifdef GLIBC_IP_OPTIONS
2227 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2228 #define OPTSTYLE 1
2229 #else
2230 #define OPTSTYLE 2
2231 #endif
2232 #elif defined DARWIN_IP_OPTIONS
2233 #define OPTSTYLE 2
2234 #else
2235 #define OPTSTYLE 3
2236 #endif
2237
2238 if (!host_checking && !sender_host_notsocket)
2239 {
2240 #if OPTSTYLE == 1
2241 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2242 struct ip_options *ipopt = store_get(optlen);
2243 #elif OPTSTYLE == 2
2244 struct ip_opts ipoptblock;
2245 struct ip_opts *ipopt = &ipoptblock;
2246 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2247 #else
2248 struct ipoption ipoptblock;
2249 struct ipoption *ipopt = &ipoptblock;
2250 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2251 #endif
2252
2253 /* Occasional genuine failures of getsockopt() have been seen - for
2254 example, "reset by peer". Therefore, just log and give up on this
2255 call, unless the error is ENOPROTOOPT. This error is given by systems
2256 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2257 of writing. So for that error, carry on - we just can't do an IP options
2258 check. */
2259
2260 DEBUG(D_receive) debug_printf("checking for IP options\n");
2261
2262 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2263 &optlen) < 0)
2264 {
2265 if (errno != ENOPROTOOPT)
2266 {
2267 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2268 host_and_ident(FALSE), strerror(errno));
2269 smtp_printf("451 SMTP service not available\r\n");
2270 return FALSE;
2271 }
2272 }
2273
2274 /* Deal with any IP options that are set. On the systems I have looked at,
2275 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2276 more logging data than will fit in big_buffer. Nevertheless, after somebody
2277 questioned this code, I've added in some paranoid checking. */
2278
2279 else if (optlen > 0)
2280 {
2281 uschar *p = big_buffer;
2282 uschar *pend = big_buffer + big_buffer_size;
2283 uschar *opt, *adptr;
2284 int optcount;
2285 struct in_addr addr;
2286
2287 #if OPTSTYLE == 1
2288 uschar *optstart = (uschar *)(ipopt->__data);
2289 #elif OPTSTYLE == 2
2290 uschar *optstart = (uschar *)(ipopt->ip_opts);
2291 #else
2292 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2293 #endif
2294
2295 DEBUG(D_receive) debug_printf("IP options exist\n");
2296
2297 Ustrcpy(p, "IP options on incoming call:");
2298 p += Ustrlen(p);
2299
2300 for (opt = optstart; opt != NULL &&
2301 opt < (uschar *)(ipopt) + optlen;)
2302 {
2303 switch (*opt)
2304 {
2305 case IPOPT_EOL:
2306 opt = NULL;
2307 break;
2308
2309 case IPOPT_NOP:
2310 opt++;
2311 break;
2312
2313 case IPOPT_SSRR:
2314 case IPOPT_LSRR:
2315 if (!string_format(p, pend-p, " %s [@%s",
2316 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2317 #if OPTSTYLE == 1
2318 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2319 #elif OPTSTYLE == 2
2320 inet_ntoa(ipopt->ip_dst)))
2321 #else
2322 inet_ntoa(ipopt->ipopt_dst)))
2323 #endif
2324 {
2325 opt = NULL;
2326 break;
2327 }
2328
2329 p += Ustrlen(p);
2330 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2331 adptr = opt + 3;
2332 while (optcount-- > 0)
2333 {
2334 memcpy(&addr, adptr, sizeof(addr));
2335 if (!string_format(p, pend - p - 1, "%s%s",
2336 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2337 {
2338 opt = NULL;
2339 break;
2340 }
2341 p += Ustrlen(p);
2342 adptr += sizeof(struct in_addr);
2343 }
2344 *p++ = ']';
2345 opt += opt[1];
2346 break;
2347
2348 default:
2349 {
2350 int i;
2351 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2352 Ustrcat(p, "[ ");
2353 p += 2;
2354 for (i = 0; i < opt[1]; i++)
2355 {
2356 sprintf(CS p, "%2.2x ", opt[i]);
2357 p += 3;
2358 }
2359 *p++ = ']';
2360 }
2361 opt += opt[1];
2362 break;
2363 }
2364 }
2365
2366 *p = 0;
2367 log_write(0, LOG_MAIN, "%s", big_buffer);
2368
2369 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2370
2371 log_write(0, LOG_MAIN|LOG_REJECT,
2372 "connection from %s refused (IP options)", host_and_ident(FALSE));
2373
2374 smtp_printf("554 SMTP service not available\r\n");
2375 return FALSE;
2376 }
2377
2378 /* Length of options = 0 => there are no options */
2379
2380 else DEBUG(D_receive) debug_printf("no IP options found\n");
2381 }
2382 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2383
2384 /* Set keep-alive in socket options. The option is on by default. This
2385 setting is an attempt to get rid of some hanging connections that stick in
2386 read() when the remote end (usually a dialup) goes away. */
2387
2388 if (smtp_accept_keepalive && !sender_host_notsocket)
2389 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2390
2391 /* If the current host matches host_lookup, set the name by doing a
2392 reverse lookup. On failure, sender_host_name will be NULL and
2393 host_lookup_failed will be TRUE. This may or may not be serious - optional
2394 checks later. */
2395
2396 if (verify_check_host(&host_lookup) == OK)
2397 {
2398 (void)host_name_lookup();
2399 host_build_sender_fullhost();
2400 }
2401
2402 /* Delay this until we have the full name, if it is looked up. */
2403
2404 set_process_info("handling incoming connection from %s",
2405 host_and_ident(FALSE));
2406
2407 /* Expand smtp_receive_timeout, if needed */
2408
2409 if (smtp_receive_timeout_s)
2410 {
2411 uschar * exp;
2412 if ( !(exp = expand_string(smtp_receive_timeout_s))
2413 || !(*exp)
2414 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2415 )
2416 log_write(0, LOG_MAIN|LOG_PANIC,
2417 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2418 }
2419
2420 /* Test for explicit connection rejection */
2421
2422 if (verify_check_host(&host_reject_connection) == OK)
2423 {
2424 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2425 "from %s (host_reject_connection)", host_and_ident(FALSE));
2426 smtp_printf("554 SMTP service not available\r\n");
2427 return FALSE;
2428 }
2429
2430 /* Test with TCP Wrappers if so configured. There is a problem in that
2431 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2432 such as disks dying. In these cases, it is desirable to reject with a 4xx
2433 error instead of a 5xx error. There isn't a "right" way to detect such
2434 problems. The following kludge is used: errno is zeroed before calling
2435 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2436 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2437 not exist). */
2438
2439 #ifdef USE_TCP_WRAPPERS
2440 errno = 0;
2441 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2442 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2443 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2444 expand_string_message);
2445
2446 if (!hosts_ctl(tcp_wrappers_name,
2447 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2448 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2449 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2450 {
2451 if (errno == 0 || errno == ENOENT)
2452 {
2453 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2454 log_write(L_connection_reject,
2455 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2456 "(tcp wrappers)", host_and_ident(FALSE));
2457 smtp_printf("554 SMTP service not available\r\n");
2458 }
2459 else
2460 {
2461 int save_errno = errno;
2462 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2463 "errno value %d\n", save_errno);
2464 log_write(L_connection_reject,
2465 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2466 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2467 smtp_printf("451 Temporary local problem - please try later\r\n");
2468 }
2469 return FALSE;
2470 }
2471 #endif
2472
2473 /* Check for reserved slots. The value of smtp_accept_count has already been
2474 incremented to include this process. */
2475
2476 if (smtp_accept_max > 0 &&
2477 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2478 {
2479 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2480 {
2481 log_write(L_connection_reject,
2482 LOG_MAIN, "temporarily refused connection from %s: not in "
2483 "reserve list: connected=%d max=%d reserve=%d%s",
2484 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2485 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2486 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2487 "please try again later\r\n", smtp_active_hostname);
2488 return FALSE;
2489 }
2490 reserved_host = TRUE;
2491 }
2492
2493 /* If a load level above which only messages from reserved hosts are
2494 accepted is set, check the load. For incoming calls via the daemon, the
2495 check is done in the superior process if there are no reserved hosts, to
2496 save a fork. In all cases, the load average will already be available
2497 in a global variable at this point. */
2498
2499 if (smtp_load_reserve >= 0 &&
2500 load_average > smtp_load_reserve &&
2501 !reserved_host &&
2502 verify_check_host(&smtp_reserve_hosts) != OK)
2503 {
2504 log_write(L_connection_reject,
2505 LOG_MAIN, "temporarily refused connection from %s: not in "
2506 "reserve list and load average = %.2f", host_and_ident(FALSE),
2507 (double)load_average/1000.0);
2508 smtp_printf("421 %s: Too much load; please try again later\r\n",
2509 smtp_active_hostname);
2510 return FALSE;
2511 }
2512
2513 /* Determine whether unqualified senders or recipients are permitted
2514 for this host. Unfortunately, we have to do this every time, in order to
2515 set the flags so that they can be inspected when considering qualifying
2516 addresses in the headers. For a site that permits no qualification, this
2517 won't take long, however. */
2518
2519 allow_unqualified_sender =
2520 verify_check_host(&sender_unqualified_hosts) == OK;
2521
2522 allow_unqualified_recipient =
2523 verify_check_host(&recipient_unqualified_hosts) == OK;
2524
2525 /* Determine whether HELO/EHLO is required for this host. The requirement
2526 can be hard or soft. */
2527
2528 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2529 if (!helo_required)
2530 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2531
2532 /* Determine whether this hosts is permitted to send syntactic junk
2533 after a HELO or EHLO command. */
2534
2535 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2536 }
2537
2538 /* For batch SMTP input we are now done. */
2539
2540 if (smtp_batched_input) return TRUE;
2541
2542 /* If valid Proxy Protocol source is connecting, set up session.
2543 * Failure will not allow any SMTP function other than QUIT. */
2544
2545 #ifdef SUPPORT_PROXY
2546 proxy_session = FALSE;
2547 proxy_session_failed = FALSE;
2548 if (check_proxy_protocol_host())
2549 setup_proxy_protocol_host();
2550 #endif
2551
2552 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2553 smtps port for use with older style SSL MTAs. */
2554
2555 #ifdef SUPPORT_TLS
2556 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2557 return FALSE;
2558 #endif
2559
2560 /* Run the connect ACL if it exists */
2561
2562 user_msg = NULL;
2563 if (acl_smtp_connect)
2564 {
2565 int rc;
2566 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2567 &log_msg)) != OK)
2568 {
2569 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2570 return FALSE;
2571 }
2572 }
2573
2574 /* Output the initial message for a two-way SMTP connection. It may contain
2575 newlines, which then cause a multi-line response to be given. */
2576
2577 code = US"220"; /* Default status code */
2578 esc = US""; /* Default extended status code */
2579 esclen = 0; /* Length of esc */
2580
2581 if (!user_msg)
2582 {
2583 if (!(s = expand_string(smtp_banner)))
2584 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2585 "failed: %s", smtp_banner, expand_string_message);
2586 }
2587 else
2588 {
2589 int codelen = 3;
2590 s = user_msg;
2591 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2592 if (codelen > 4)
2593 {
2594 esc = code + 4;
2595 esclen = codelen - 4;
2596 }
2597 }
2598
2599 /* Remove any terminating newlines; might as well remove trailing space too */
2600
2601 p = s + Ustrlen(s);
2602 while (p > s && isspace(p[-1])) p--;
2603 *p = 0;
2604
2605 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2606 is all contained in a single IP packet. The original code wrote out the
2607 greeting using several calls to fprint/fputc, and on busy servers this could
2608 cause it to be split over more than one packet - which caused CC:Mail to fall
2609 over when it got the second part of the greeting after sending its first
2610 command. Sigh. To try to avoid this, build the complete greeting message
2611 first, and output it in one fell swoop. This gives a better chance of it
2612 ending up as a single packet. */
2613
2614 ss = store_get(size);
2615 ptr = 0;
2616
2617 p = s;
2618 do /* At least once, in case we have an empty string */
2619 {
2620 int len;
2621 uschar *linebreak = Ustrchr(p, '\n');
2622 ss = string_catn(ss, &size, &ptr, code, 3);
2623 if (linebreak == NULL)
2624 {
2625 len = Ustrlen(p);
2626 ss = string_catn(ss, &size, &ptr, US" ", 1);
2627 }
2628 else
2629 {
2630 len = linebreak - p;
2631 ss = string_catn(ss, &size, &ptr, US"-", 1);
2632 }
2633 ss = string_catn(ss, &size, &ptr, esc, esclen);
2634 ss = string_catn(ss, &size, &ptr, p, len);
2635 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2636 p += len;
2637 if (linebreak != NULL) p++;
2638 }
2639 while (*p != 0);
2640
2641 ss[ptr] = 0; /* string_cat leaves room for this */
2642
2643 /* Before we write the banner, check that there is no input pending, unless
2644 this synchronisation check is disabled. */
2645
2646 if (!check_sync())
2647 {
2648 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2649 "synchronization error (input sent without waiting for greeting): "
2650 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2651 string_printing(smtp_inptr));
2652 smtp_printf("554 SMTP synchronization error\r\n");
2653 return FALSE;
2654 }
2655
2656 /* Now output the banner */
2657
2658 smtp_printf("%s", ss);
2659 return TRUE;
2660 }
2661
2662
2663
2664
2665
2666 /*************************************************
2667 * Handle SMTP syntax and protocol errors *
2668 *************************************************/
2669
2670 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2671 to do so. Then transmit the error response. The return value depends on the
2672 number of syntax and protocol errors in this SMTP session.
2673
2674 Arguments:
2675 type error type, given as a log flag bit
2676 code response code; <= 0 means don't send a response
2677 data data to reflect in the response (can be NULL)
2678 errmess the error message
2679
2680 Returns: -1 limit of syntax/protocol errors NOT exceeded
2681 +1 limit of syntax/protocol errors IS exceeded
2682
2683 These values fit in with the values of the "done" variable in the main
2684 processing loop in smtp_setup_msg(). */
2685
2686 static int
2687 synprot_error(int type, int code, uschar *data, uschar *errmess)
2688 {
2689 int yield = -1;
2690
2691 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2692 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2693 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2694
2695 if (++synprot_error_count > smtp_max_synprot_errors)
2696 {
2697 yield = 1;
2698 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2699 "syntax or protocol errors (last command was \"%s\")",
2700 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2701 }
2702
2703 if (code > 0)
2704 {
2705 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2706 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2707 if (yield == 1)
2708 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2709 }
2710
2711 return yield;
2712 }
2713
2714
2715
2716
2717 /*************************************************
2718 * Send SMTP response, possibly multiline *
2719 *************************************************/
2720
2721 /* There are, it seems, broken clients out there that cannot handle multiline
2722 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2723 output nothing for non-final calls, and only the first line for anything else.
2724
2725 Arguments:
2726 code SMTP code, may involve extended status codes
2727 codelen length of smtp code; if > 4 there's an ESC
2728 final FALSE if the last line isn't the final line
2729 msg message text, possibly containing newlines
2730
2731 Returns: nothing
2732 */
2733
2734 void
2735 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2736 {
2737 int esclen = 0;
2738 uschar *esc = US"";
2739
2740 if (!final && no_multiline_responses) return;
2741
2742 if (codelen > 4)
2743 {
2744 esc = code + 4;
2745 esclen = codelen - 4;
2746 }
2747
2748 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2749 have had the same. Note: this code is also present in smtp_printf(). It would
2750 be tidier to have it only in one place, but when it was added, it was easier to
2751 do it that way, so as not to have to mess with the code for the RCPT command,
2752 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2753
2754 if (rcpt_in_progress)
2755 {
2756 if (rcpt_smtp_response == NULL)
2757 rcpt_smtp_response = string_copy(msg);
2758 else if (rcpt_smtp_response_same &&
2759 Ustrcmp(rcpt_smtp_response, msg) != 0)
2760 rcpt_smtp_response_same = FALSE;
2761 rcpt_in_progress = FALSE;
2762 }
2763
2764 /* Not output the message, splitting it up into multiple lines if necessary. */
2765
2766 for (;;)
2767 {
2768 uschar *nl = Ustrchr(msg, '\n');
2769 if (nl == NULL)
2770 {
2771 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2772 return;
2773 }
2774 else if (nl[1] == 0 || no_multiline_responses)
2775 {
2776 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2777 (int)(nl - msg), msg);
2778 return;
2779 }
2780 else
2781 {
2782 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2783 msg = nl + 1;
2784 while (isspace(*msg)) msg++;
2785 }
2786 }
2787 }
2788
2789
2790
2791
2792 /*************************************************
2793 * Parse user SMTP message *
2794 *************************************************/
2795
2796 /* This function allows for user messages overriding the response code details
2797 by providing a suitable response code string at the start of the message
2798 user_msg. Check the message for starting with a response code and optionally an
2799 extended status code. If found, check that the first digit is valid, and if so,
2800 change the code pointer and length to use the replacement. An invalid code
2801 causes a panic log; in this case, if the log messages is the same as the user
2802 message, we must also adjust the value of the log message to show the code that
2803 is actually going to be used (the original one).
2804
2805 This function is global because it is called from receive.c as well as within
2806 this module.
2807
2808 Note that the code length returned includes the terminating whitespace
2809 character, which is always included in the regex match.
2810
2811 Arguments:
2812 code SMTP code, may involve extended status codes
2813 codelen length of smtp code; if > 4 there's an ESC
2814 msg message text
2815 log_msg optional log message, to be adjusted with the new SMTP code
2816 check_valid if true, verify the response code
2817
2818 Returns: nothing
2819 */
2820
2821 void
2822 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2823 BOOL check_valid)
2824 {
2825 int n;
2826 int ovector[3];
2827
2828 if (!msg || !*msg) return;
2829
2830 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2831 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
2832
2833 if (check_valid && (*msg)[0] != (*code)[0])
2834 {
2835 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2836 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2837 if (log_msg != NULL && *log_msg == *msg)
2838 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2839 }
2840 else
2841 {
2842 *code = *msg;
2843 *codelen = ovector[1]; /* Includes final space */
2844 }
2845 *msg += ovector[1]; /* Chop the code off the message */
2846 return;
2847 }
2848
2849
2850
2851
2852 /*************************************************
2853 * Handle an ACL failure *
2854 *************************************************/
2855
2856 /* This function is called when acl_check() fails. As well as calls from within
2857 this module, it is called from receive.c for an ACL after DATA. It sorts out
2858 logging the incident, and sets up the error response. A message containing
2859 newlines is turned into a multiline SMTP response, but for logging, only the
2860 first line is used.
2861
2862 There's a table of default permanent failure response codes to use in
2863 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2864 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2865 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2866 state, because there are broken clients that try VRFY before RCPT. A 5xx
2867 response should be given only when the address is positively known to be
2868 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2869 no explicit code, but if there is one we let it know best.
2870 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2871
2872 From Exim 4.63, it is possible to override the response code details by
2873 providing a suitable response code string at the start of the message provided
2874 in user_msg. The code's first digit is checked for validity.
2875
2876 Arguments:
2877 where where the ACL was called from
2878 rc the failure code
2879 user_msg a message that can be included in an SMTP response
2880 log_msg a message for logging
2881
2882 Returns: 0 in most cases
2883 2 if the failure code was FAIL_DROP, in which case the
2884 SMTP connection should be dropped (this value fits with the
2885 "done" variable in smtp_setup_msg() below)
2886 */
2887
2888 int
2889 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2890 {
2891 BOOL drop = rc == FAIL_DROP;
2892 int codelen = 3;
2893 uschar *smtp_code;
2894 uschar *lognl;
2895 uschar *sender_info = US"";
2896 uschar *what =
2897 #ifdef WITH_CONTENT_SCAN
2898 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
2899 #endif
2900 where == ACL_WHERE_PREDATA ? US"DATA" :
2901 where == ACL_WHERE_DATA ? US"after DATA" :
2902 #ifndef DISABLE_PRDR
2903 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
2904 #endif
2905 smtp_cmd_data ?
2906 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
2907 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
2908
2909 if (drop) rc = FAIL;
2910
2911 /* Set the default SMTP code, and allow a user message to change it. */
2912
2913 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2914 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2915 where != ACL_WHERE_VRFY);
2916
2917 /* We used to have sender_address here; however, there was a bug that was not
2918 updating sender_address after a rewrite during a verify. When this bug was
2919 fixed, sender_address at this point became the rewritten address. I'm not sure
2920 this is what should be logged, so I've changed to logging the unrewritten
2921 address to retain backward compatibility. */
2922
2923 #ifndef WITH_CONTENT_SCAN
2924 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2925 #else
2926 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2927 #endif
2928 {
2929 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2930 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2931 sender_host_authenticated ? US" A=" : US"",
2932 sender_host_authenticated ? sender_host_authenticated : US"",
2933 sender_host_authenticated && authenticated_id ? US":" : US"",
2934 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2935 );
2936 }
2937
2938 /* If there's been a sender verification failure with a specific message, and
2939 we have not sent a response about it yet, do so now, as a preliminary line for
2940 failures, but not defers. However, always log it for defer, and log it for fail
2941 unless the sender_verify_fail log selector has been turned off. */
2942
2943 if (sender_verified_failed &&
2944 !testflag(sender_verified_failed, af_sverify_told))
2945 {
2946 BOOL save_rcpt_in_progress = rcpt_in_progress;
2947 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2948
2949 setflag(sender_verified_failed, af_sverify_told);
2950
2951 if (rc != FAIL || LOGGING(sender_verify_fail))
2952 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2953 host_and_ident(TRUE),
2954 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2955 sender_verified_failed->address,
2956 (sender_verified_failed->message == NULL)? US"" :
2957 string_sprintf(": %s", sender_verified_failed->message));
2958
2959 if (rc == FAIL && sender_verified_failed->user_message)
2960 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2961 testflag(sender_verified_failed, af_verify_pmfail)?
2962 "Postmaster verification failed while checking <%s>\n%s\n"
2963 "Several RFCs state that you are required to have a postmaster\n"
2964 "mailbox for each mail domain. This host does not accept mail\n"
2965 "from domains whose servers reject the postmaster address."
2966 :
2967 testflag(sender_verified_failed, af_verify_nsfail)?
2968 "Callback setup failed while verifying <%s>\n%s\n"
2969 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2970 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2971 "RFC requirements, and stops you from receiving standard bounce\n"
2972 "messages. This host does not accept mail from domains whose servers\n"
2973 "refuse bounces."
2974 :
2975 "Verification failed for <%s>\n%s",
2976 sender_verified_failed->address,
2977 sender_verified_failed->user_message));
2978
2979 rcpt_in_progress = save_rcpt_in_progress;
2980 }
2981
2982 /* Sort out text for logging */
2983
2984 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
2985 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
2986
2987 /* Send permanent failure response to the command, but the code used isn't
2988 always a 5xx one - see comments at the start of this function. If the original
2989 rc was FAIL_DROP we drop the connection and yield 2. */
2990
2991 if (rc == FAIL)
2992 smtp_respond(smtp_code, codelen, TRUE,
2993 user_msg ? user_msg : US"Administrative prohibition");
2994
2995 /* Send temporary failure response to the command. Don't give any details,
2996 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2997 verb, and for a header verify when smtp_return_error_details is set.
2998
2999 This conditional logic is all somewhat of a mess because of the odd
3000 interactions between temp_details and return_error_details. One day it should
3001 be re-implemented in a tidier fashion. */
3002
3003 else
3004 if (acl_temp_details && user_msg)
3005 {
3006 if ( smtp_return_error_details
3007 && sender_verified_failed
3008 && sender_verified_failed->message
3009 )
3010 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3011
3012 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3013 }
3014 else
3015 smtp_respond(smtp_code, codelen, TRUE,
3016 US"Temporary local problem - please try later");
3017
3018 /* Log the incident to the logs that are specified by log_reject_target
3019 (default main, reject). This can be empty to suppress logging of rejections. If
3020 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3021 is closing if required and return 2. */
3022
3023 if (log_reject_target != 0)
3024 {
3025 #ifdef SUPPORT_TLS
3026 uschar * tls = s_tlslog(NULL, NULL, NULL);
3027 if (!tls) tls = US"";
3028 #else
3029 uschar * tls = US"";
3030 #endif
3031 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3032 log_reject_target, "%s%s%s %s%srejected %s%s",
3033 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3034 host_and_ident(TRUE),
3035 tls,
3036 sender_info,
3037 rc == FAIL ? US"" : US"temporarily ",
3038 what, log_msg);
3039 }
3040
3041 if (!drop) return 0;
3042
3043 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3044 smtp_get_connection_info());
3045
3046 /* Run the not-quit ACL, but without any custom messages. This should not be a
3047 problem, because we get here only if some other ACL has issued "drop", and
3048 in that case, *its* custom messages will have been used above. */
3049
3050 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3051 return 2;
3052 }
3053
3054
3055
3056
3057 /*************************************************
3058 * Handle SMTP exit when QUIT is not given *
3059 *************************************************/
3060
3061 /* This function provides a logging/statistics hook for when an SMTP connection
3062 is dropped on the floor or the other end goes away. It's a global function
3063 because it's called from receive.c as well as this module. As well as running
3064 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3065 response, either with a custom message from the ACL, or using a default. There
3066 is one case, however, when no message is output - after "drop". In that case,
3067 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3068 passed to this function.
3069
3070 In case things go wrong while processing this function, causing an error that
3071 may re-enter this function, there is a recursion check.
3072
3073 Arguments:
3074 reason What $smtp_notquit_reason will be set to in the ACL;
3075 if NULL, the ACL is not run
3076 code The error code to return as part of the response
3077 defaultrespond The default message if there's no user_msg
3078
3079 Returns: Nothing
3080 */
3081
3082 void
3083 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3084 {
3085 int rc;
3086 uschar *user_msg = NULL;
3087 uschar *log_msg = NULL;
3088
3089 /* Check for recursive acll */
3090
3091 if (smtp_exit_function_called)
3092 {
3093 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3094 reason);
3095 return;
3096 }
3097 smtp_exit_function_called = TRUE;
3098
3099 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3100
3101 if (acl_smtp_notquit && reason)
3102 {
3103 smtp_notquit_reason = reason;
3104 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3105 &log_msg)) == ERROR)
3106 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3107 log_msg);
3108 }
3109
3110 /* Write an SMTP response if we are expected to give one. As the default
3111 responses are all internal, they should always fit in the buffer, but code a
3112 warning, just in case. Note that string_vformat() still leaves a complete
3113 string, even if it is incomplete. */
3114
3115 if (code && defaultrespond)
3116 {
3117 if (user_msg)
3118 smtp_respond(code, 3, TRUE, user_msg);
3119 else
3120 {
3121 uschar buffer[128];
3122 va_list ap;
3123 va_start(ap, defaultrespond);
3124 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3125 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3126 smtp_printf("%s %s\r\n", code, buffer);
3127 va_end(ap);
3128 }
3129 mac_smtp_fflush();
3130 }
3131 }
3132
3133
3134
3135
3136 /*************************************************
3137 * Verify HELO argument *
3138 *************************************************/
3139
3140 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3141 matched. It is also called from ACL processing if verify = helo is used and
3142 verification was not previously tried (i.e. helo_try_verify_hosts was not
3143 matched). The result of its processing is to set helo_verified and
3144 helo_verify_failed. These variables should both be FALSE for this function to
3145 be called.
3146
3147 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3148 for IPv6 ::ffff: literals.
3149
3150 Argument: none
3151 Returns: TRUE if testing was completed;
3152 FALSE on a temporary failure
3153 */
3154
3155 BOOL
3156 smtp_verify_helo(void)
3157 {
3158 BOOL yield = TRUE;
3159
3160 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3161 sender_helo_name);
3162
3163 if (sender_helo_name == NULL)
3164 {
3165 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3166 }
3167
3168 /* Deal with the case of -bs without an IP address */
3169
3170 else if (sender_host_address == NULL)
3171 {
3172 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3173 helo_verified = TRUE;
3174 }
3175
3176 /* Deal with the more common case when there is a sending IP address */
3177
3178 else if (sender_helo_name[0] == '[')
3179 {
3180 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3181 Ustrlen(sender_host_address)) == 0;
3182
3183 #if HAVE_IPV6
3184 if (!helo_verified)
3185 {
3186 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3187 helo_verified = Ustrncmp(sender_helo_name + 1,
3188 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3189 }
3190 #endif
3191
3192 HDEBUG(D_receive)
3193 { if (helo_verified) debug_printf("matched host address\n"); }
3194 }
3195
3196 /* Do a reverse lookup if one hasn't already given a positive or negative
3197 response. If that fails, or the name doesn't match, try checking with a forward
3198 lookup. */
3199
3200 else
3201 {
3202 if (sender_host_name == NULL && !host_lookup_failed)
3203 yield = host_name_lookup() != DEFER;
3204
3205 /* If a host name is known, check it and all its aliases. */
3206
3207 if (sender_host_name)
3208 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3209 {
3210 sender_helo_dnssec = sender_host_dnssec;
3211 HDEBUG(D_receive) debug_printf("matched host name\n");
3212 }
3213 else
3214 {
3215 uschar **aliases = sender_host_aliases;
3216 while (*aliases)
3217 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3218 {
3219 sender_helo_dnssec = sender_host_dnssec;
3220 break;
3221 }
3222
3223 HDEBUG(D_receive) if (helo_verified)
3224 debug_printf("matched alias %s\n", *(--aliases));
3225 }
3226
3227 /* Final attempt: try a forward lookup of the helo name */
3228
3229 if (!helo_verified)
3230 {
3231 int rc;
3232 host_item h;
3233 dnssec_domains d;
3234 host_item *hh;
3235
3236 h.name = sender_helo_name;
3237 h.address = NULL;
3238 h.mx = MX_NONE;
3239 h.next = NULL;
3240 d.request = US"*";
3241 d.require = US"";
3242
3243 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3244 sender_helo_name);
3245 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3246 NULL, NULL, NULL, &d, NULL, NULL);
3247 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3248 for (hh = &h; hh; hh = hh->next)
3249 if (Ustrcmp(hh->address, sender_host_address) == 0)
3250 {
3251 helo_verified = TRUE;
3252 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3253 HDEBUG(D_receive)
3254 {
3255 debug_printf("IP address for %s matches calling address\n"
3256 "Forward DNS security status: %sverified\n",
3257 sender_helo_name, sender_helo_dnssec ? "" : "un");
3258 }
3259 break;
3260 }
3261 }
3262 }
3263
3264 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3265 return yield;
3266 }
3267
3268
3269
3270
3271 /*************************************************
3272 * Send user response message *
3273 *************************************************/
3274
3275 /* This function is passed a default response code and a user message. It calls
3276 smtp_message_code() to check and possibly modify the response code, and then
3277 calls smtp_respond() to transmit the response. I put this into a function
3278 just to avoid a lot of repetition.
3279
3280 Arguments:
3281 code the response code
3282 user_msg the user message
3283
3284 Returns: nothing
3285 */
3286
3287 static void
3288 smtp_user_msg(uschar *code, uschar *user_msg)
3289 {
3290 int len = 3;
3291 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3292 smtp_respond(code, len, TRUE, user_msg);
3293 }
3294
3295
3296
3297 static int
3298 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3299 {
3300 const uschar *set_id = NULL;
3301 int rc, i;
3302
3303 /* Run the checking code, passing the remainder of the command line as
3304 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3305 it as the only set numerical variable. The authenticator may set $auth<n>
3306 and also set other numeric variables. The $auth<n> variables are preferred
3307 nowadays; the numerical variables remain for backwards compatibility.
3308
3309 Afterwards, have a go at expanding the set_id string, even if
3310 authentication failed - for bad passwords it can be useful to log the
3311 userid. On success, require set_id to expand and exist, and put it in
3312 authenticated_id. Save this in permanent store, as the working store gets
3313 reset at HELO, RSET, etc. */
3314
3315 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3316 expand_nmax = 0;
3317 expand_nlength[0] = 0; /* $0 contains nothing */
3318
3319 rc = (au->info->servercode)(au, smtp_cmd_data);
3320 if (au->set_id) set_id = expand_string(au->set_id);
3321 expand_nmax = -1; /* Reset numeric variables */
3322 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3323
3324 /* The value of authenticated_id is stored in the spool file and printed in
3325 log lines. It must not contain binary zeros or newline characters. In
3326 normal use, it never will, but when playing around or testing, this error
3327 can (did) happen. To guard against this, ensure that the id contains only
3328 printing characters. */
3329
3330 if (set_id) set_id = string_printing(set_id);
3331
3332 /* For the non-OK cases, set up additional logging data if set_id
3333 is not empty. */
3334
3335 if (rc != OK)
3336 set_id = set_id && *set_id
3337 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3338
3339 /* Switch on the result */
3340
3341 switch(rc)
3342 {
3343 case OK:
3344 if (!au->set_id || set_id) /* Complete success */
3345 {
3346 if (set_id) authenticated_id = string_copy_malloc(set_id);
3347 sender_host_authenticated = au->name;
3348 authentication_failed = FALSE;
3349 authenticated_fail_id = NULL; /* Impossible to already be set? */
3350
3351 received_protocol =
3352 (sender_host_address ? protocols : protocols_local)
3353 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3354 *s = *ss = US"235 Authentication succeeded";
3355 authenticated_by = au;
3356 break;
3357 }
3358
3359 /* Authentication succeeded, but we failed to expand the set_id string.
3360 Treat this as a temporary error. */
3361
3362 auth_defer_msg = expand_string_message;
3363 /* Fall through */
3364
3365 case DEFER:
3366 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3367 *s = string_sprintf("435 Unable to authenticate at present%s",
3368 auth_defer_user_msg);
3369 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3370 set_id, auth_defer_msg);
3371 break;
3372
3373 case BAD64:
3374 *s = *ss = US"501 Invalid base64 data";
3375 break;
3376
3377 case CANCELLED:
3378 *s = *ss = US"501 Authentication cancelled";
3379 break;
3380
3381 case UNEXPECTED:
3382 *s = *ss = US"553 Initial data not expected";
3383 break;
3384
3385 case FAIL:
3386 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3387 *s = US"535 Incorrect authentication data";
3388 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3389 break;
3390
3391 default:
3392 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3393 *s = US"435 Internal error";
3394 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3395 "check", set_id, rc);
3396 break;
3397 }
3398
3399 return rc;
3400 }
3401
3402
3403
3404
3405
3406 static int
3407 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3408 {
3409 int rd;
3410 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3411 {
3412 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3413 *recipient);
3414 rd = Ustrlen(recipient) + 1;
3415 *recipient = rewrite_address_qualify(*recipient, TRUE);
3416 return rd;
3417 }
3418 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3419 smtp_cmd_data);
3420 log_write(L_smtp_syntax_error,
3421 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3422 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3423 return 0;
3424 }
3425
3426
3427
3428
3429 static void
3430 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3431 {
3432 HAD(SCH_QUIT);
3433 incomplete_transaction_log(US"QUIT");
3434 if (acl_smtp_quit)
3435 {
3436 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3437 if (rc == ERROR)
3438 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3439 *log_msgp);
3440 }
3441 if (*user_msgp)
3442 smtp_respond(US"221", 3, TRUE, *user_msgp);
3443 else
3444 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3445
3446 #ifdef SUPPORT_TLS
3447 tls_close(TRUE, TRUE);
3448 #endif
3449
3450 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3451 smtp_get_connection_info());
3452 }
3453
3454
3455 static void
3456 smtp_rset_handler(void)
3457 {
3458 HAD(SCH_RSET);
3459 incomplete_transaction_log(US"RSET");
3460 smtp_printf("250 Reset OK\r\n");
3461 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3462 }
3463
3464
3465
3466 /*************************************************
3467 * Initialize for SMTP incoming message *
3468 *************************************************/
3469
3470 /* This function conducts the initial dialogue at the start of an incoming SMTP
3471 message, and builds a list of recipients. However, if the incoming message
3472 is part of a batch (-bS option) a separate function is called since it would
3473 be messy having tests splattered about all over this function. This function
3474 therefore handles the case where interaction is occurring. The input and output
3475 files are set up in smtp_in and smtp_out.
3476
3477 The global recipients_list is set to point to a vector of recipient_item
3478 blocks, whose number is given by recipients_count. This is extended by the
3479 receive_add_recipient() function. The global variable sender_address is set to
3480 the sender's address. The yield is +1 if a message has been successfully
3481 started, 0 if a QUIT command was encountered or the connection was refused from
3482 the particular host, or -1 if the connection was lost.
3483
3484 Argument: none
3485
3486 Returns: > 0 message successfully started (reached DATA)
3487 = 0 QUIT read or end of file reached or call refused
3488 < 0 lost connection
3489 */
3490
3491 int
3492 smtp_setup_msg(void)
3493 {
3494 int done = 0;
3495 BOOL toomany = FALSE;
3496 BOOL discarded = FALSE;
3497 BOOL last_was_rej_mail = FALSE;
3498 BOOL last_was_rcpt = FALSE;
3499 void *reset_point = store_get(0);
3500
3501 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3502
3503 /* Reset for start of new message. We allow one RSET not to be counted as a
3504 nonmail command, for those MTAs that insist on sending it between every
3505 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3506 TLS between messages (an Exim client may do this if it has messages queued up
3507 for the host). Note: we do NOT reset AUTH at this point. */
3508
3509 smtp_reset(reset_point);
3510 message_ended = END_NOTSTARTED;
3511
3512 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3513
3514 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3515 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3516 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3517 #ifdef SUPPORT_TLS
3518 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3519 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3520 #endif
3521
3522 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3523
3524 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3525
3526 /* Batched SMTP is handled in a different function. */
3527
3528 if (smtp_batched_input) return smtp_setup_batch_msg();
3529
3530 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3531 value. The values are 2 larger than the required yield of the function. */
3532
3533 while (done <= 0)
3534 {
3535 const uschar **argv;
3536 uschar *etrn_command;
3537 uschar *etrn_serialize_key;
3538 uschar *errmess;
3539 uschar *log_msg, *smtp_code;
3540 uschar *user_msg = NULL;
3541 uschar *recipient = NULL;
3542 uschar *hello = NULL;
3543 uschar *s, *ss;
3544 BOOL was_rej_mail = FALSE;
3545 BOOL was_rcpt = FALSE;
3546 void (*oldsignal)(int);
3547 pid_t pid;
3548 int start, end, sender_domain, recipient_domain;
3549 int ptr, size, rc;
3550 int c;
3551 auth_instance *au;
3552 uschar *orcpt = NULL;
3553 int flags;
3554
3555 #ifdef AUTH_TLS
3556 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3557 if ( tls_in.active >= 0
3558 && tls_in.peercert
3559 && tls_in.certificate_verified
3560 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3561 )
3562 {
3563 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3564 if ( acl_smtp_auth
3565 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3566 &user_msg, &log_msg)) != OK
3567 )
3568 {
3569 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3570 continue;
3571 }
3572
3573 for (au = auths; au; au = au->next)
3574 if (strcmpic(US"tls", au->driver_name) == 0)
3575 {
3576 smtp_cmd_data = NULL;
3577
3578 if (smtp_in_auth(au, &s, &ss) == OK)
3579 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3580 else
3581 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3582 break;
3583 }
3584 }
3585 #endif
3586
3587 #ifdef TCP_QUICKACK
3588 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3589 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3590 US &off, sizeof(off));
3591 #endif
3592
3593 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3594 {
3595 /* The AUTH command is not permitted to occur inside a transaction, and may
3596 occur successfully only once per connection. Actually, that isn't quite
3597 true. When TLS is started, all previous information about a connection must
3598 be discarded, so a new AUTH is permitted at that time.
3599
3600 AUTH may only be used when it has been advertised. However, it seems that
3601 there are clients that send AUTH when it hasn't been advertised, some of
3602 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3603 So there's a get-out that allows this to happen.
3604
3605 AUTH is initially labelled as a "nonmail command" so that one occurrence
3606 doesn't get counted. We change the label here so that multiple failing
3607 AUTHS will eventually hit the nonmail threshold. */
3608
3609 case AUTH_CMD:
3610 HAD(SCH_AUTH);
3611 authentication_failed = TRUE;
3612 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3613
3614 if (!auth_advertised && !allow_auth_unadvertised)
3615 {
3616 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3617 US"AUTH command used when not advertised");
3618 break;
3619 }
3620 if (sender_host_authenticated)
3621 {
3622 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3623 US"already authenticated");
3624 break;
3625 }
3626 if (sender_address)
3627 {
3628 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3629 US"not permitted in mail transaction");
3630 break;
3631 }
3632
3633 /* Check the ACL */
3634
3635 if ( acl_smtp_auth
3636 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3637 &user_msg, &log_msg)) != OK
3638 )
3639 {
3640 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3641 break;
3642 }
3643
3644 /* Find the name of the requested authentication mechanism. */
3645
3646 s = smtp_cmd_data;
3647 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3648 {
3649 if (!isalnum(c) && c != '-' && c != '_')
3650 {
3651 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3652 US"invalid character in authentication mechanism name");
3653 goto COMMAND_LOOP;
3654 }
3655 smtp_cmd_data++;
3656 }
3657
3658 /* If not at the end of the line, we must be at white space. Terminate the
3659 name and move the pointer on to any data that may be present. */
3660
3661 if (*smtp_cmd_data != 0)
3662 {
3663 *smtp_cmd_data++ = 0;
3664 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3665 }
3666
3667 /* Search for an authentication mechanism which is configured for use
3668 as a server and which has been advertised (unless, sigh, allow_auth_
3669 unadvertised is set). */
3670
3671 for (au = auths; au; au = au->next)
3672 if (strcmpic(s, au->public_name) == 0 && au->server &&
3673 (au->advertised || allow_auth_unadvertised))
3674 break;
3675
3676 if (au)
3677 {
3678 c = smtp_in_auth(au, &s, &ss);
3679
3680 smtp_printf("%s\r\n", s);
3681 if (c != OK)
3682 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3683 au->name, host_and_ident(FALSE), ss);
3684 }
3685 else
3686 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3687 string_sprintf("%s authentication mechanism not supported", s));
3688
3689 break; /* AUTH_CMD */
3690
3691 /* The HELO/EHLO commands are permitted to appear in the middle of a
3692 session as well as at the beginning. They have the effect of a reset in
3693 addition to their other functions. Their absence at the start cannot be
3694 taken to be an error.
3695
3696 RFC 2821 says:
3697
3698 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3699 or 502 failure replies MUST be returned as appropriate. The SMTP
3700 server MUST stay in the same state after transmitting these replies
3701 that it was in before the EHLO was received.
3702
3703 Therefore, we do not do the reset until after checking the command for
3704 acceptability. This change was made for Exim release 4.11. Previously
3705 it did the reset first. */
3706
3707 case HELO_CMD:
3708 HAD(SCH_HELO);
3709 hello = US"HELO";
3710 esmtp = FALSE;
3711 goto HELO_EHLO;
3712
3713 case EHLO_CMD:
3714 HAD(SCH_EHLO);
3715 hello = US"EHLO";
3716 esmtp = TRUE;
3717
3718 HELO_EHLO: /* Common code for HELO and EHLO */
3719 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3720 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3721
3722 /* Reject the HELO if its argument was invalid or non-existent. A
3723 successful check causes the argument to be saved in malloc store. */
3724
3725 if (!check_helo(smtp_cmd_data))
3726 {
3727 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3728
3729 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3730 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3731 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3732 string_printing(smtp_cmd_argument));
3733
3734 if (++synprot_error_count > smtp_max_synprot_errors)
3735 {
3736 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3737 "syntax or protocol errors (last command was \"%s\")",
3738 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3739 done = 1;
3740 }
3741
3742 break;
3743 }
3744
3745 /* If sender_host_unknown is true, we have got here via the -bs interface,
3746 not called from inetd. Otherwise, we are running an IP connection and the
3747 host address will be set. If the helo name is the primary name of this
3748 host and we haven't done a reverse lookup, force one now. If helo_required
3749 is set, ensure that the HELO name matches the actual host. If helo_verify
3750 is set, do the same check, but softly. */
3751
3752 if (!sender_host_unknown)
3753 {
3754 BOOL old_helo_verified = helo_verified;
3755 uschar *p = smtp_cmd_data;
3756
3757 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3758 *p = 0;
3759
3760 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3761 because otherwise the log can be confusing. */
3762
3763 if (sender_host_name == NULL &&
3764 (deliver_domain = sender_helo_name, /* set $domain */
3765 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3766 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3767 (void)host_name_lookup();
3768
3769 /* Rebuild the fullhost info to include the HELO name (and the real name
3770 if it was looked up.) */
3771
3772 host_build_sender_fullhost(); /* Rebuild */
3773 set_process_info("handling%s incoming connection from %s",
3774 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3775
3776 /* Verify if configured. This doesn't give much security, but it does
3777 make some people happy to be able to do it. If helo_required is set,
3778 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3779 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3780 now obsolescent, since the verification can now be requested selectively
3781 at ACL time. */
3782
3783 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
3784 if (helo_required || helo_verify)
3785 {
3786 BOOL tempfail = !smtp_verify_helo();
3787 if (!helo_verified)
3788 {
3789 if (helo_required)
3790 {
3791 smtp_printf("%d %s argument does not match calling host\r\n",
3792 tempfail? 451 : 550, hello);
3793 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3794 tempfail? "temporarily " : "",
3795 hello, sender_helo_name, host_and_ident(FALSE));
3796 helo_verified = old_helo_verified;
3797 break; /* End of HELO/EHLO processing */
3798 }
3799 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3800 "helo_try_verify_hosts\n", hello);
3801 }
3802 }
3803 }
3804
3805 #ifdef EXPERIMENTAL_SPF
3806 /* set up SPF context */
3807 spf_init(sender_helo_name, sender_host_address);
3808 #endif
3809
3810 /* Apply an ACL check if one is defined; afterwards, recheck
3811 synchronization in case the client started sending in a delay. */
3812
3813 if (acl_smtp_helo)
3814 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3815 &user_msg, &log_msg)) != OK)
3816 {
3817 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3818 sender_helo_name = NULL;
3819 host_build_sender_fullhost(); /* Rebuild */
3820 break;
3821 }
3822 else if (!check_sync()) goto SYNC_FAILURE;
3823
3824 /* Generate an OK reply. The default string includes the ident if present,
3825 and also the IP address if present. Reflecting back the ident is intended
3826 as a deterrent to mail forgers. For maximum efficiency, and also because
3827 some broken systems expect each response to be in a single packet, arrange
3828 that the entire reply is sent in one write(). */
3829
3830 auth_advertised = FALSE;
3831 pipelining_advertised = FALSE;
3832 #ifdef SUPPORT_TLS
3833 tls_advertised = FALSE;
3834 #endif
3835 dsn_advertised = FALSE;
3836 #ifdef SUPPORT_I18N
3837 smtputf8_advertised = FALSE;
3838 #endif
3839
3840 smtp_code = US"250 "; /* Default response code plus space*/
3841 if (user_msg == NULL)
3842 {
3843 s = string_sprintf("%.3s %s Hello %s%s%s",
3844 smtp_code,
3845 smtp_active_hostname,
3846 (sender_ident == NULL)? US"" : sender_ident,
3847 (sender_ident == NULL)? US"" : US" at ",
3848 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3849
3850 ptr = Ustrlen(s);
3851 size = ptr + 1;
3852
3853 if (sender_host_address != NULL)
3854 {
3855 s = string_catn(s, &size, &ptr, US" [", 2);
3856 s = string_cat (s, &size, &ptr, sender_host_address);
3857 s = string_catn(s, &size, &ptr, US"]", 1);
3858 }
3859 }
3860
3861 /* A user-supplied EHLO greeting may not contain more than one line. Note
3862 that the code returned by smtp_message_code() includes the terminating
3863 whitespace character. */
3864
3865 else
3866 {
3867 char *ss;
3868 int codelen = 4;
3869 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
3870 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3871 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3872 {
3873 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3874 "newlines: message truncated: %s", string_printing(s));
3875 *ss = 0;
3876 }
3877 ptr = Ustrlen(s);
3878 size = ptr + 1;
3879 }
3880
3881 s = string_catn(s, &size, &ptr, US"\r\n", 2);
3882
3883 /* If we received EHLO, we must create a multiline response which includes
3884 the functions supported. */
3885
3886 if (esmtp)
3887 {
3888 s[3] = '-';
3889
3890 /* I'm not entirely happy with this, as an MTA is supposed to check
3891 that it has enough room to accept a message of maximum size before
3892 it sends this. However, there seems little point in not sending it.
3893 The actual size check happens later at MAIL FROM time. By postponing it
3894 till then, VRFY and EXPN can be used after EHLO when space is short. */
3895
3896 if (thismessage_size_limit > 0)
3897 {
3898 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3899 thismessage_size_limit);
3900 s = string_cat(s, &size, &ptr, big_buffer);
3901 }
3902 else
3903 {
3904 s = string_catn(s, &size, &ptr, smtp_code, 3);
3905 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
3906 }
3907
3908 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3909 clean; if it has an 8-bit character in its hand, it just sends it. It
3910 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3911 However, some users want this option simply in order to stop MUAs
3912 mangling messages that contain top-bit-set characters. It is therefore
3913 provided as an option. */
3914
3915 if (accept_8bitmime)
3916 {
3917 s = string_catn(s, &size, &ptr, smtp_code, 3);
3918 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3919 }
3920
3921 /* Advertise DSN support if configured to do so. */
3922 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
3923 {
3924 s = string_catn(s, &size, &ptr, smtp_code, 3);
3925 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
3926 dsn_advertised = TRUE;
3927 }
3928
3929 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
3930 permitted to issue them; a check is made when any host actually tries. */
3931
3932 if (acl_smtp_etrn)
3933 {
3934 s = string_catn(s, &size, &ptr, smtp_code, 3);
3935 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
3936 }
3937 if (acl_smtp_vrfy)
3938 {
3939 s = string_catn(s, &size, &ptr, smtp_code, 3);
3940 s = string_catn(s, &size, &ptr, US"-VRFY\r\n", 7);
3941 }
3942 if (acl_smtp_expn)
3943 {
3944 s = string_catn(s, &size, &ptr, smtp_code, 3);
3945 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
3946 }
3947
3948 /* Exim is quite happy with pipelining, so let the other end know that
3949 it is safe to use it, unless advertising is disabled. */
3950
3951 if (pipelining_enable &&
3952 verify_check_host(&pipelining_advertise_hosts) == OK)
3953 {
3954 s = string_catn(s, &size, &ptr, smtp_code, 3);
3955 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3956 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3957 pipelining_advertised = TRUE;
3958 }
3959
3960
3961 /* If any server authentication mechanisms are configured, advertise
3962 them if the current host is in auth_advertise_hosts. The problem with
3963 advertising always is that some clients then require users to
3964 authenticate (and aren't configurable otherwise) even though it may not
3965 be necessary (e.g. if the host is in host_accept_relay).
3966
3967 RFC 2222 states that SASL mechanism names contain only upper case
3968 letters, so output the names in upper case, though we actually recognize
3969 them in either case in the AUTH command. */
3970
3971 if ( auths
3972 #ifdef AUTH_TLS
3973 && !sender_host_authenticated
3974 #endif
3975 && verify_check_host(&auth_advertise_hosts) == OK
3976 )
3977 {
3978 auth_instance *au;
3979 BOOL first = TRUE;
3980 for (au = auths; au; au = au->next)
3981 if (au->server && (au->advertise_condition == NULL ||
3982 expand_check_condition(au->advertise_condition, au->name,
3983 US"authenticator")))
3984 {
3985 int saveptr;
3986 if (first)
3987 {
3988 s = string_catn(s, &size, &ptr, smtp_code, 3);
3989 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
3990 first = FALSE;
3991 auth_advertised = TRUE;
3992 }
3993 saveptr = ptr;
3994 s = string_catn(s, &size, &ptr, US" ", 1);
3995 s = string_cat (s, &size, &ptr, au->public_name);
3996 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3997 au->advertised = TRUE;
3998 }
3999 else
4000 au->advertised = FALSE;
4001
4002 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
4003 }
4004
4005 /* RFC 3030 CHUNKING */
4006
4007 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4008 {
4009 s = string_catn(s, &size, &ptr, smtp_code, 3);
4010 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
4011 chunking_offered = TRUE;
4012 chunking_state = CHUNKING_OFFERED;
4013 }
4014
4015 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4016 if it has been included in the binary, and the host matches
4017 tls_advertise_hosts. We must *not* advertise if we are already in a
4018 secure connection. */
4019
4020 #ifdef SUPPORT_TLS
4021 if (tls_in.active < 0 &&
4022 verify_check_host(&tls_advertise_hosts) != FAIL)
4023 {
4024 s = string_catn(s, &size, &ptr, smtp_code, 3);
4025 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
4026 tls_advertised = TRUE;
4027 }
4028 #endif
4029
4030 #ifndef DISABLE_PRDR
4031 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4032 if (prdr_enable)
4033 {
4034 s = string_catn(s, &size, &ptr, smtp_code, 3);
4035 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
4036 }
4037 #endif
4038
4039 #ifdef SUPPORT_I18N
4040 if ( accept_8bitmime
4041 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4042 {
4043 s = string_catn(s, &size, &ptr, smtp_code, 3);
4044 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
4045 smtputf8_advertised = TRUE;
4046 }
4047 #endif
4048
4049 /* Finish off the multiline reply with one that is always available. */
4050
4051 s = string_catn(s, &size, &ptr, smtp_code, 3);
4052 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
4053 }
4054
4055 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4056 has been seen. */
4057
4058 s[ptr] = 0;
4059
4060 #ifdef SUPPORT_TLS
4061 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
4062 #endif
4063
4064 {
4065 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
4066 }
4067 DEBUG(D_receive)
4068 {
4069 uschar *cr;
4070 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
4071 memmove(cr, cr + 1, (ptr--) - (cr - s));
4072 debug_printf("SMTP>> %s", s);
4073 }
4074 helo_seen = TRUE;
4075
4076 /* Reset the protocol and the state, abandoning any previous message. */
4077 received_protocol =
4078 (sender_host_address ? protocols : protocols_local)
4079 [ (esmtp
4080 ? pextend + (sender_host_authenticated ? pauthed : 0)
4081 : pnormal)
4082 + (tls_in.active >= 0 ? pcrpted : 0)
4083 ];
4084 smtp_reset(reset_point);
4