Avoid reading too much data before TLS handshake
[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 * Read data until newline or end of buffer *
926 *************************************************/
927 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
928 read an entire buffer and assume there will be nothing past a proxy protocol
929 header. Our approach normally is to use stdio, but again that relies upon
930 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
931 reading _nothing_ before client TLS handshake. So we don't want to use the
932 usual buffering reads which may read enough to block TLS starting.
933
934 So unfortunately we're down to "read one byte at a time, with a syscall each,
935 and expect a little overhead", for all proxy-opened connections which are v1,
936 just to handle the TLS-on-connect case. Since SSL functions wrap the
937 underlying fd, we can't assume that we can feed them any already-read content.
938
939 We need to know where to read to, the max capacity, and we'll read until we
940 get a CR and one more character. Let the caller scream if it's CR+!LF.
941
942 Return the amount read.
943 */
944
945 static int
946 swallow_until_crlf(int fd, void *vto, int capacity)
947 {
948 uschar *to = (uschar *)vto;
949 int have = 0;
950 int ret;
951 int last = 0;
952
953 while (capacity > 0) {
954 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
955 if (ret == -1)
956 return -1;
957 have++;
958 if (last)
959 return have;
960 if (*to == '\r')
961 last = 1;
962 capacity--;
963 to++;
964 }
965 // reached end without having room for a final newline, abort
966 errno = EOVERFLOW;
967 return -1;
968 }
969
970 /*************************************************
971 * Setup host for proxy protocol *
972 *************************************************/
973 /* The function configures the connection based on a header from the
974 inbound host to use Proxy Protocol. The specification is very exact
975 so exit with an error if do not find the exact required pieces. This
976 includes an incorrect number of spaces separating args.
977
978 Arguments: none
979 Returns: Boolean success
980 */
981
982 static void
983 setup_proxy_protocol_host()
984 {
985 union {
986 struct {
987 uschar line[108];
988 } v1;
989 struct {
990 uschar sig[12];
991 uint8_t ver_cmd;
992 uint8_t fam;
993 uint16_t len;
994 union {
995 struct { /* TCP/UDP over IPv4, len = 12 */
996 uint32_t src_addr;
997 uint32_t dst_addr;
998 uint16_t src_port;
999 uint16_t dst_port;
1000 } ip4;
1001 struct { /* TCP/UDP over IPv6, len = 36 */
1002 uint8_t src_addr[16];
1003 uint8_t dst_addr[16];
1004 uint16_t src_port;
1005 uint16_t dst_port;
1006 } ip6;
1007 struct { /* AF_UNIX sockets, len = 216 */
1008 uschar src_addr[108];
1009 uschar dst_addr[108];
1010 } unx;
1011 } addr;
1012 } v2;
1013 } hdr;
1014
1015 /* Temp variables used in PPv2 address:port parsing */
1016 uint16_t tmpport;
1017 char tmpip[INET_ADDRSTRLEN];
1018 struct sockaddr_in tmpaddr;
1019 char tmpip6[INET6_ADDRSTRLEN];
1020 struct sockaddr_in6 tmpaddr6;
1021
1022 int get_ok = 0;
1023 int size, ret;
1024 int fd = fileno(smtp_in);
1025 #define PROXY_INITIAL_READ 12
1026 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1027 uschar * iptype; /* To display debug info */
1028 struct timeval tv;
1029 struct timeval tvtmp;
1030 socklen_t vslen = sizeof(struct timeval);
1031 BOOL yield = FALSE;
1032
1033 /* Save current socket timeout values */
1034 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1035
1036 /* Proxy Protocol host must send header within a short time
1037 (default 3 seconds) or it's considered invalid */
1038 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1039 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1040 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1041 goto bad;
1042
1043 do
1044 {
1045 /* The inbound host was declared to be a Proxy Protocol host, so
1046 don't do a PEEK into the data, actually slurp it up. */
1047 /* We assume that the zie of a v2sig is less than the size of a complete
1048 PROXYv1 line, so that we will _have_ to read more data; "PROXY TCPn\r\n"
1049 is 12, so an IP address pushes it over, so we're good. */
1050 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1051 }
1052 while (ret == -1 && errno == EINTR);
1053
1054 if (ret == -1)
1055 goto proxyfail;
1056
1057 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1058 {
1059 uint8_t ver, cmd;
1060 int ret2nd;
1061
1062 /* It's now safe to read the rest. */
1063 do {
1064 ret2nd = recv(fd, (uschar*)&hdr + ret, sizeof(hdr)-ret, 0);
1065 } while (ret2nd == -1 && errno == EINTR);
1066 if (ret2nd == -1)
1067 goto proxyfail;
1068 ret += ret2nd;
1069
1070 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1071 cmd = (hdr.v2.ver_cmd & 0x0f);
1072
1073 /* May 2014: haproxy combined the version and command into one byte to
1074 allow two full bytes for the length field in order to proxy SSL
1075 connections. SSL Proxy is not supported in this version of Exim, but
1076 must still separate values here. */
1077
1078 if (ver != 0x02)
1079 {
1080 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1081 goto proxyfail;
1082 }
1083 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
1084 /* The v2 header will always be 16 bytes per the spec. */
1085 size = 16 + ntohs(hdr.v2.len);
1086 if (ret < size)
1087 {
1088 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
1089 ret, size);
1090 goto proxyfail;
1091 }
1092 switch (cmd)
1093 {
1094 case 0x01: /* PROXY command */
1095 switch (hdr.v2.fam)
1096 {
1097 case 0x11: /* TCPv4 address type */
1098 iptype = US"IPv4";
1099 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1100 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1101 if (!string_is_ip_address(US tmpip, NULL))
1102 {
1103 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1104 goto proxyfail;
1105 }
1106 proxy_local_address = sender_host_address;
1107 sender_host_address = string_copy(US tmpip);
1108 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1109 proxy_local_port = sender_host_port;
1110 sender_host_port = tmpport;
1111 /* Save dest ip/port */
1112 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1113 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1114 if (!string_is_ip_address(US tmpip, NULL))
1115 {
1116 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1117 goto proxyfail;
1118 }
1119 proxy_external_address = string_copy(US tmpip);
1120 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1121 proxy_external_port = tmpport;
1122 goto done;
1123 case 0x21: /* TCPv6 address type */
1124 iptype = US"IPv6";
1125 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1126 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1127 if (!string_is_ip_address(US tmpip6, NULL))
1128 {
1129 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1130 goto proxyfail;
1131 }
1132 proxy_local_address = sender_host_address;
1133 sender_host_address = string_copy(US tmpip6);
1134 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1135 proxy_local_port = sender_host_port;
1136 sender_host_port = tmpport;
1137 /* Save dest ip/port */
1138 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1139 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1140 if (!string_is_ip_address(US tmpip6, NULL))
1141 {
1142 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1143 goto proxyfail;
1144 }
1145 proxy_external_address = string_copy(US tmpip6);
1146 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1147 proxy_external_port = tmpport;
1148 goto done;
1149 default:
1150 DEBUG(D_receive)
1151 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1152 hdr.v2.fam);
1153 goto proxyfail;
1154 }
1155 /* Unsupported protocol, keep local connection address */
1156 break;
1157 case 0x00: /* LOCAL command */
1158 /* Keep local connection address for LOCAL */
1159 iptype = US"local";
1160 break;
1161 default:
1162 DEBUG(D_receive)
1163 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1164 goto proxyfail;
1165 }
1166 }
1167 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1168 {
1169 uschar *p;
1170 uschar *end;
1171 uschar *sp; /* Utility variables follow */
1172 int tmp_port;
1173 int r2;
1174 char *endc;
1175
1176 /* get the rest of the line */
1177 r2 = swallow_until_crlf(fd, (uschar*)&hdr + ret, sizeof(hdr)-ret);
1178 if (r2 == -1)
1179 goto proxyfail;
1180 ret += r2;
1181
1182 p = string_copy(hdr.v1.line);
1183 end = memchr(p, '\r', ret - 1);
1184
1185 if (!end || end[1] != '\n')
1186 {
1187 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1188 goto proxyfail;
1189 }
1190 *end = '\0'; /* Terminate the string */
1191 size = end + 2 - p; /* Skip header + CRLF */
1192 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1193 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1194 /* Step through the string looking for the required fields. Ensure
1195 strict adherence to required formatting, exit for any error. */
1196 p += 5;
1197 if (!isspace(*(p++)))
1198 {
1199 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1200 goto proxyfail;
1201 }
1202 if (!Ustrncmp(p, CCS"TCP4", 4))
1203 iptype = US"IPv4";
1204 else if (!Ustrncmp(p,CCS"TCP6", 4))
1205 iptype = US"IPv6";
1206 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1207 {
1208 iptype = US"Unknown";
1209 goto done;
1210 }
1211 else
1212 {
1213 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1214 goto proxyfail;
1215 }
1216
1217 p += Ustrlen(iptype);
1218 if (!isspace(*(p++)))
1219 {
1220 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1221 goto proxyfail;
1222 }
1223 /* Find the end of the arg */
1224 if ((sp = Ustrchr(p, ' ')) == NULL)
1225 {
1226 DEBUG(D_receive)
1227 debug_printf("Did not find proxied src %s\n", iptype);
1228 goto proxyfail;
1229 }
1230 *sp = '\0';
1231 if(!string_is_ip_address(p, NULL))
1232 {
1233 DEBUG(D_receive)
1234 debug_printf("Proxied src arg is not an %s address\n", iptype);
1235 goto proxyfail;
1236 }
1237 proxy_local_address = sender_host_address;
1238 sender_host_address = p;
1239 p = sp + 1;
1240 if ((sp = Ustrchr(p, ' ')) == NULL)
1241 {
1242 DEBUG(D_receive)
1243 debug_printf("Did not find proxy dest %s\n", iptype);
1244 goto proxyfail;
1245 }
1246 *sp = '\0';
1247 if(!string_is_ip_address(p, NULL))
1248 {
1249 DEBUG(D_receive)
1250 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1251 goto proxyfail;
1252 }
1253 proxy_external_address = p;
1254 p = sp + 1;
1255 if ((sp = Ustrchr(p, ' ')) == NULL)
1256 {
1257 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1258 goto proxyfail;
1259 }
1260 *sp = '\0';
1261 tmp_port = strtol(CCS p, &endc, 10);
1262 if (*endc || tmp_port == 0)
1263 {
1264 DEBUG(D_receive)
1265 debug_printf("Proxied src port '%s' not an integer\n", p);
1266 goto proxyfail;
1267 }
1268 proxy_local_port = sender_host_port;
1269 sender_host_port = tmp_port;
1270 p = sp + 1;
1271 if ((sp = Ustrchr(p, '\0')) == NULL)
1272 {
1273 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1274 goto proxyfail;
1275 }
1276 tmp_port = strtol(CCS p, &endc, 10);
1277 if (*endc || tmp_port == 0)
1278 {
1279 DEBUG(D_receive)
1280 debug_printf("Proxy dest port '%s' not an integer\n", p);
1281 goto proxyfail;
1282 }
1283 proxy_external_port = tmp_port;
1284 /* Already checked for /r /n above. Good V1 header received. */
1285 }
1286 else
1287 {
1288 /* Wrong protocol */
1289 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1290 (void) swallow_until_crlf(fd, (uschar*)&hdr + ret, sizeof(hdr)-ret);
1291 goto proxyfail;
1292 }
1293
1294 done:
1295 DEBUG(D_receive)
1296 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1297 yield = proxy_session;
1298
1299 /* Don't flush any potential buffer contents. Any input on proxyfail
1300 should cause a synchronization failure */
1301
1302 proxyfail:
1303 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1304
1305 bad:
1306 if (yield)
1307 {
1308 sender_host_name = NULL;
1309 (void) host_name_lookup();
1310 host_build_sender_fullhost();
1311 }
1312 else
1313 {
1314 proxy_session_failed = TRUE;
1315 DEBUG(D_receive)
1316 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1317 }
1318
1319 return;
1320 }
1321 #endif
1322
1323 /*************************************************
1324 * Read one command line *
1325 *************************************************/
1326
1327 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1328 There are sites that don't do this, and in any case internal SMTP probably
1329 should check only for LF. Consequently, we check here for LF only. The line
1330 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1331 an unknown command. The command is read into the global smtp_cmd_buffer so that
1332 it is available via $smtp_command.
1333
1334 The character reading routine sets up a timeout for each block actually read
1335 from the input (which may contain more than one command). We set up a special
1336 signal handler that closes down the session on a timeout. Control does not
1337 return when it runs.
1338
1339 Arguments:
1340 check_sync if TRUE, check synchronization rules if global option is TRUE
1341 buffer_lim maximum to buffer in lower layer
1342
1343 Returns: a code identifying the command (enumerated above)
1344 */
1345
1346 static int
1347 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1348 {
1349 int c;
1350 int ptr = 0;
1351 smtp_cmd_list *p;
1352 BOOL hadnull = FALSE;
1353
1354 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1355
1356 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1357 {
1358 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1359 {
1360 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1361 return OTHER_CMD;
1362 }
1363 if (c == 0)
1364 {
1365 hadnull = TRUE;
1366 c = '?';
1367 }
1368 smtp_cmd_buffer[ptr++] = c;
1369 }
1370
1371 receive_linecount++; /* For BSMTP errors */
1372 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1373
1374 /* If hit end of file, return pseudo EOF command. Whether we have a
1375 part-line already read doesn't matter, since this is an error state. */
1376
1377 if (c == EOF) return EOF_CMD;
1378
1379 /* Remove any CR and white space at the end of the line, and terminate the
1380 string. */
1381
1382 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1383 smtp_cmd_buffer[ptr] = 0;
1384
1385 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1386
1387 /* NULLs are not allowed in SMTP commands */
1388
1389 if (hadnull) return BADCHAR_CMD;
1390
1391 /* Scan command list and return identity, having set the data pointer
1392 to the start of the actual data characters. Check for SMTP synchronization
1393 if required. */
1394
1395 for (p = cmd_list; p < cmd_list_end; p++)
1396 {
1397 #ifdef SUPPORT_PROXY
1398 /* Only allow QUIT command if Proxy Protocol parsing failed */
1399 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1400 continue;
1401 #endif
1402 if ( p->len
1403 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1404 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1405 || smtp_cmd_buffer[p->len] == 0
1406 || smtp_cmd_buffer[p->len] == ' '
1407 ) )
1408 {
1409 if (smtp_inptr < smtp_inend && /* Outstanding input */
1410 p->cmd < sync_cmd_limit && /* Command should sync */
1411 check_sync && /* Local flag set */
1412 smtp_enforce_sync && /* Global flag set */
1413 sender_host_address != NULL && /* Not local input */
1414 !sender_host_notsocket) /* Really is a socket */
1415 return BADSYN_CMD;
1416
1417 /* The variables $smtp_command and $smtp_command_argument point into the
1418 unmodified input buffer. A copy of the latter is taken for actual
1419 processing, so that it can be chopped up into separate parts if necessary,
1420 for example, when processing a MAIL command options such as SIZE that can
1421 follow the sender address. */
1422
1423 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1424 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1425 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1426 smtp_cmd_data = smtp_data_buffer;
1427
1428 /* Count non-mail commands from those hosts that are controlled in this
1429 way. The default is all hosts. We don't waste effort checking the list
1430 until we get a non-mail command, but then cache the result to save checking
1431 again. If there's a DEFER while checking the host, assume it's in the list.
1432
1433 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1434 start of each incoming message by fiddling with the value in the table. */
1435
1436 if (!p->is_mail_cmd)
1437 {
1438 if (count_nonmail == TRUE_UNSET) count_nonmail =
1439 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1440 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1441 return TOO_MANY_NONMAIL_CMD;
1442 }
1443
1444 /* If there is data for a command that does not expect it, generate the
1445 error here. */
1446
1447 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1448 }
1449 }
1450
1451 #ifdef SUPPORT_PROXY
1452 /* Only allow QUIT command if Proxy Protocol parsing failed */
1453 if (proxy_session && proxy_session_failed)
1454 return PROXY_FAIL_IGNORE_CMD;
1455 #endif
1456
1457 /* Enforce synchronization for unknown commands */
1458
1459 if (smtp_inptr < smtp_inend && /* Outstanding input */
1460 check_sync && /* Local flag set */
1461 smtp_enforce_sync && /* Global flag set */
1462 sender_host_address != NULL && /* Not local input */
1463 !sender_host_notsocket) /* Really is a socket */
1464 return BADSYN_CMD;
1465
1466 return OTHER_CMD;
1467 }
1468
1469
1470
1471 /*************************************************
1472 * Forced closedown of call *
1473 *************************************************/
1474
1475 /* This function is called from log.c when Exim is dying because of a serious
1476 disaster, and also from some other places. If an incoming non-batched SMTP
1477 channel is open, it swallows the rest of the incoming message if in the DATA
1478 phase, sends the reply string, and gives an error to all subsequent commands
1479 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1480 smtp_in.
1481
1482 Arguments:
1483 message SMTP reply string to send, excluding the code
1484
1485 Returns: nothing
1486 */
1487
1488 void
1489 smtp_closedown(uschar *message)
1490 {
1491 if (smtp_in == NULL || smtp_batched_input) return;
1492 receive_swallow_smtp();
1493 smtp_printf("421 %s\r\n", message);
1494
1495 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1496 {
1497 case EOF_CMD:
1498 return;
1499
1500 case QUIT_CMD:
1501 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1502 mac_smtp_fflush();
1503 return;
1504
1505 case RSET_CMD:
1506 smtp_printf("250 Reset OK\r\n");
1507 break;
1508
1509 default:
1510 smtp_printf("421 %s\r\n", message);
1511 break;
1512 }
1513 }
1514
1515
1516
1517
1518 /*************************************************
1519 * Set up connection info for logging *
1520 *************************************************/
1521
1522 /* This function is called when logging information about an SMTP connection.
1523 It sets up appropriate source information, depending on the type of connection.
1524 If sender_fullhost is NULL, we are at a very early stage of the connection;
1525 just use the IP address.
1526
1527 Argument: none
1528 Returns: a string describing the connection
1529 */
1530
1531 uschar *
1532 smtp_get_connection_info(void)
1533 {
1534 const uschar * hostname = sender_fullhost
1535 ? sender_fullhost : sender_host_address;
1536
1537 if (host_checking)
1538 return string_sprintf("SMTP connection from %s", hostname);
1539
1540 if (sender_host_unknown || sender_host_notsocket)
1541 return string_sprintf("SMTP connection from %s", sender_ident);
1542
1543 if (is_inetd)
1544 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1545
1546 if (LOGGING(incoming_interface) && interface_address != NULL)
1547 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1548 interface_address, interface_port);
1549
1550 return string_sprintf("SMTP connection from %s", hostname);
1551 }
1552
1553
1554
1555 #ifdef SUPPORT_TLS
1556 /* Append TLS-related information to a log line
1557
1558 Arguments:
1559 s String under construction: allocated string to extend, or NULL
1560 sizep Pointer to current allocation size (update on return), or NULL
1561 ptrp Pointer to index for new entries in string (update on return), or NULL
1562
1563 Returns: Allocated string or NULL
1564 */
1565 static uschar *
1566 s_tlslog(uschar * s, int * sizep, int * ptrp)
1567 {
1568 int size = sizep ? *sizep : 0;
1569 int ptr = ptrp ? *ptrp : 0;
1570
1571 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1572 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1573 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1574 s = string_append(s, &size, &ptr, 2, US" CV=",
1575 tls_in.certificate_verified? "yes":"no");
1576 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1577 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1578 string_printing(tls_in.peerdn), US"\"");
1579 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1580 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1581 string_printing(tls_in.sni), US"\"");
1582
1583 if (s)
1584 {
1585 s[ptr] = '\0';
1586 if (sizep) *sizep = size;
1587 if (ptrp) *ptrp = ptr;
1588 }
1589 return s;
1590 }
1591 #endif
1592
1593 /*************************************************
1594 * Log lack of MAIL if so configured *
1595 *************************************************/
1596
1597 /* This function is called when an SMTP session ends. If the log selector
1598 smtp_no_mail is set, write a log line giving some details of what has happened
1599 in the SMTP session.
1600
1601 Arguments: none
1602 Returns: nothing
1603 */
1604
1605 void
1606 smtp_log_no_mail(void)
1607 {
1608 int size, ptr, i;
1609 uschar *s, *sep;
1610
1611 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1612 return;
1613
1614 s = NULL;
1615 size = ptr = 0;
1616
1617 if (sender_host_authenticated != NULL)
1618 {
1619 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1620 if (authenticated_id != NULL)
1621 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1622 }
1623
1624 #ifdef SUPPORT_TLS
1625 s = s_tlslog(s, &size, &ptr);
1626 #endif
1627
1628 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1629 US" C=..." : US" C=";
1630 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1631 {
1632 if (smtp_connection_had[i] != SCH_NONE)
1633 {
1634 s = string_append(s, &size, &ptr, 2, sep,
1635 smtp_names[smtp_connection_had[i]]);
1636 sep = US",";
1637 }
1638 }
1639
1640 for (i = 0; i < smtp_ch_index; i++)
1641 {
1642 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1643 sep = US",";
1644 }
1645
1646 if (s != NULL) s[ptr] = 0; else s = US"";
1647 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1648 host_and_ident(FALSE),
1649 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1650 s);
1651 }
1652
1653
1654
1655 /*************************************************
1656 * Check HELO line and set sender_helo_name *
1657 *************************************************/
1658
1659 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1660 the domain name of the sending host, or an ip literal in square brackets. The
1661 argument is placed in sender_helo_name, which is in malloc store, because it
1662 must persist over multiple incoming messages. If helo_accept_junk is set, this
1663 host is permitted to send any old junk (needed for some broken hosts).
1664 Otherwise, helo_allow_chars can be used for rogue characters in general
1665 (typically people want to let in underscores).
1666
1667 Argument:
1668 s the data portion of the line (already past any white space)
1669
1670 Returns: TRUE or FALSE
1671 */
1672
1673 static BOOL
1674 check_helo(uschar *s)
1675 {
1676 uschar *start = s;
1677 uschar *end = s + Ustrlen(s);
1678 BOOL yield = helo_accept_junk;
1679
1680 /* Discard any previous helo name */
1681
1682 if (sender_helo_name != NULL)
1683 {
1684 store_free(sender_helo_name);
1685 sender_helo_name = NULL;
1686 }
1687
1688 /* Skip tests if junk is permitted. */
1689
1690 if (!yield)
1691 {
1692 /* Allow the new standard form for IPv6 address literals, namely,
1693 [IPv6:....], and because someone is bound to use it, allow an equivalent
1694 IPv4 form. Allow plain addresses as well. */
1695
1696 if (*s == '[')
1697 {
1698 if (end[-1] == ']')
1699 {
1700 end[-1] = 0;
1701 if (strncmpic(s, US"[IPv6:", 6) == 0)
1702 yield = (string_is_ip_address(s+6, NULL) == 6);
1703 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1704 yield = (string_is_ip_address(s+6, NULL) == 4);
1705 else
1706 yield = (string_is_ip_address(s+1, NULL) != 0);
1707 end[-1] = ']';
1708 }
1709 }
1710
1711 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1712 that have been configured (usually underscore - sigh). */
1713
1714 else if (*s != 0)
1715 {
1716 yield = TRUE;
1717 while (*s != 0)
1718 {
1719 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1720 Ustrchr(helo_allow_chars, *s) == NULL)
1721 {
1722 yield = FALSE;
1723 break;
1724 }
1725 s++;
1726 }
1727 }
1728 }
1729
1730 /* Save argument if OK */
1731
1732 if (yield) sender_helo_name = string_copy_malloc(start);
1733 return yield;
1734 }
1735
1736
1737
1738
1739
1740 /*************************************************
1741 * Extract SMTP command option *
1742 *************************************************/
1743
1744 /* This function picks the next option setting off the end of smtp_cmd_data. It
1745 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1746 things that can appear there.
1747
1748 Arguments:
1749 name point this at the name
1750 value point this at the data string
1751
1752 Returns: TRUE if found an option
1753 */
1754
1755 static BOOL
1756 extract_option(uschar **name, uschar **value)
1757 {
1758 uschar *n;
1759 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1760 while (isspace(*v)) v--;
1761 v[1] = 0;
1762 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1763 {
1764 /* Take care to not stop at a space embedded in a quoted local-part */
1765
1766 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1767 v--;
1768 }
1769
1770 n = v;
1771 if (*v == '=')
1772 {
1773 while(isalpha(n[-1])) n--;
1774 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1775 if (!isspace(n[-1])) return FALSE;
1776 n[-1] = 0;
1777 }
1778 else
1779 {
1780 n++;
1781 if (v == smtp_cmd_data) return FALSE;
1782 }
1783 *v++ = 0;
1784 *name = n;
1785 *value = v;
1786 return TRUE;
1787 }
1788
1789
1790
1791
1792
1793 /*************************************************
1794 * Reset for new message *
1795 *************************************************/
1796
1797 /* This function is called whenever the SMTP session is reset from
1798 within either of the setup functions.
1799
1800 Argument: the stacking pool storage reset point
1801 Returns: nothing
1802 */
1803
1804 static void
1805 smtp_reset(void *reset_point)
1806 {
1807 store_reset(reset_point);
1808 recipients_list = NULL;
1809 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1810 raw_recipients_count = recipients_count = recipients_list_max = 0;
1811 cancel_cutthrough_connection("smtp reset");
1812 message_linecount = 0;
1813 message_size = -1;
1814 acl_added_headers = NULL;
1815 acl_removed_headers = NULL;
1816 queue_only_policy = FALSE;
1817 rcpt_smtp_response = NULL;
1818 rcpt_smtp_response_same = TRUE;
1819 rcpt_in_progress = FALSE;
1820 deliver_freeze = FALSE; /* Can be set by ACL */
1821 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1822 fake_response = OK; /* Can be set by ACL */
1823 #ifdef WITH_CONTENT_SCAN
1824 no_mbox_unspool = FALSE; /* Can be set by ACL */
1825 #endif
1826 submission_mode = FALSE; /* Can be set by ACL */
1827 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1828 active_local_from_check = local_from_check; /* Can be set by ACL */
1829 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1830 sender_address = NULL;
1831 submission_name = NULL; /* Can be set by ACL */
1832 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1833 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1834 sender_verified_list = NULL; /* No senders verified */
1835 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1836 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1837
1838 authenticated_sender = NULL;
1839 #ifdef EXPERIMENTAL_BRIGHTMAIL
1840 bmi_run = 0;
1841 bmi_verdicts = NULL;
1842 #endif
1843 #ifndef DISABLE_DKIM
1844 dkim_signers = NULL;
1845 dkim_disable_verify = FALSE;
1846 dkim_collect_input = FALSE;
1847 #endif
1848 dsn_ret = 0;
1849 dsn_envid = NULL;
1850 #ifndef DISABLE_PRDR
1851 prdr_requested = FALSE;
1852 #endif
1853 #ifdef EXPERIMENTAL_SPF
1854 spf_header_comment = NULL;
1855 spf_received = NULL;
1856 spf_result = NULL;
1857 spf_smtp_comment = NULL;
1858 #endif
1859 #ifdef SUPPORT_I18N
1860 message_smtputf8 = FALSE;
1861 #endif
1862 body_linecount = body_zerocount = 0;
1863
1864 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1865 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1866 /* Note that ratelimiters_conn persists across resets. */
1867
1868 /* Reset message ACL variables */
1869
1870 acl_var_m = NULL;
1871
1872 /* The message body variables use malloc store. They may be set if this is
1873 not the first message in an SMTP session and the previous message caused them
1874 to be referenced in an ACL. */
1875
1876 if (message_body != NULL)
1877 {
1878 store_free(message_body);
1879 message_body = NULL;
1880 }
1881
1882 if (message_body_end != NULL)
1883 {
1884 store_free(message_body_end);
1885 message_body_end = NULL;
1886 }
1887
1888 /* Warning log messages are also saved in malloc store. They are saved to avoid
1889 repetition in the same message, but it seems right to repeat them for different
1890 messages. */
1891
1892 while (acl_warn_logged != NULL)
1893 {
1894 string_item *this = acl_warn_logged;
1895 acl_warn_logged = acl_warn_logged->next;
1896 store_free(this);
1897 }
1898 }
1899
1900
1901
1902
1903
1904 /*************************************************
1905 * Initialize for incoming batched SMTP message *
1906 *************************************************/
1907
1908 /* This function is called from smtp_setup_msg() in the case when
1909 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1910 of messages in one file with SMTP commands between them. All errors must be
1911 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1912 relevant. After an error on a sender, or an invalid recipient, the remainder
1913 of the message is skipped. The value of received_protocol is already set.
1914
1915 Argument: none
1916 Returns: > 0 message successfully started (reached DATA)
1917 = 0 QUIT read or end of file reached
1918 < 0 should not occur
1919 */
1920
1921 static int
1922 smtp_setup_batch_msg(void)
1923 {
1924 int done = 0;
1925 void *reset_point = store_get(0);
1926
1927 /* Save the line count at the start of each transaction - single commands
1928 like HELO and RSET count as whole transactions. */
1929
1930 bsmtp_transaction_linecount = receive_linecount;
1931
1932 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1933
1934 smtp_reset(reset_point); /* Reset for start of message */
1935
1936 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1937 value. The values are 2 larger than the required yield of the function. */
1938
1939 while (done <= 0)
1940 {
1941 uschar *errmess;
1942 uschar *recipient = NULL;
1943 int start, end, sender_domain, recipient_domain;
1944
1945 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1946 {
1947 /* The HELO/EHLO commands set sender_address_helo if they have
1948 valid data; otherwise they are ignored, except that they do
1949 a reset of the state. */
1950
1951 case HELO_CMD:
1952 case EHLO_CMD:
1953
1954 check_helo(smtp_cmd_data);
1955 /* Fall through */
1956
1957 case RSET_CMD:
1958 smtp_reset(reset_point);
1959 bsmtp_transaction_linecount = receive_linecount;
1960 break;
1961
1962
1963 /* The MAIL FROM command requires an address as an operand. All we
1964 do here is to parse it for syntactic correctness. The form "<>" is
1965 a special case which converts into an empty string. The start/end
1966 pointers in the original are not used further for this address, as
1967 it is the canonical extracted address which is all that is kept. */
1968
1969 case MAIL_CMD:
1970 smtp_mailcmd_count++; /* Count for no-mail log */
1971 if (sender_address != NULL)
1972 /* The function moan_smtp_batch() does not return. */
1973 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1974
1975 if (smtp_cmd_data[0] == 0)
1976 /* The function moan_smtp_batch() does not return. */
1977 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1978
1979 /* Reset to start of message */
1980
1981 smtp_reset(reset_point);
1982
1983 /* Apply SMTP rewrite */
1984
1985 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1986 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1987 US"", global_rewrite_rules) : smtp_cmd_data;
1988
1989 /* Extract the address; the TRUE flag allows <> as valid */
1990
1991 raw_sender =
1992 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1993 TRUE);
1994
1995 if (raw_sender == NULL)
1996 /* The function moan_smtp_batch() does not return. */
1997 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1998
1999 sender_address = string_copy(raw_sender);
2000
2001 /* Qualify unqualified sender addresses if permitted to do so. */
2002
2003 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
2004 {
2005 if (allow_unqualified_sender)
2006 {
2007 sender_address = rewrite_address_qualify(sender_address, FALSE);
2008 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2009 "and rewritten\n", raw_sender);
2010 }
2011 /* The function moan_smtp_batch() does not return. */
2012 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2013 "a domain");
2014 }
2015 break;
2016
2017
2018 /* The RCPT TO command requires an address as an operand. All we do
2019 here is to parse it for syntactic correctness. There may be any number
2020 of RCPT TO commands, specifying multiple senders. We build them all into
2021 a data structure that is in argc/argv format. The start/end values
2022 given by parse_extract_address are not used, as we keep only the
2023 extracted address. */
2024
2025 case RCPT_CMD:
2026 if (sender_address == NULL)
2027 /* The function moan_smtp_batch() does not return. */
2028 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2029
2030 if (smtp_cmd_data[0] == 0)
2031 /* The function moan_smtp_batch() does not return. */
2032 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
2033
2034 /* Check maximum number allowed */
2035
2036 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2037 /* The function moan_smtp_batch() does not return. */
2038 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2039 recipients_max_reject? "552": "452");
2040
2041 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2042 recipient address */
2043
2044 recipient = rewrite_existflags & rewrite_smtp
2045 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2046 global_rewrite_rules)
2047 : smtp_cmd_data;
2048
2049 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2050 &recipient_domain, FALSE);
2051
2052 if (!recipient)
2053 /* The function moan_smtp_batch() does not return. */
2054 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2055
2056 /* If the recipient address is unqualified, qualify it if permitted. Then
2057 add it to the list of recipients. */
2058
2059 if (recipient_domain == 0)
2060 {
2061 if (allow_unqualified_recipient)
2062 {
2063 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2064 recipient);
2065 recipient = rewrite_address_qualify(recipient, TRUE);
2066 }
2067 /* The function moan_smtp_batch() does not return. */
2068 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
2069 "a domain");
2070 }
2071 receive_add_recipient(recipient, -1);
2072 break;
2073
2074
2075 /* The DATA command is legal only if it follows successful MAIL FROM
2076 and RCPT TO commands. This function is complete when a valid DATA
2077 command is encountered. */
2078
2079 case DATA_CMD:
2080 if (sender_address == NULL || recipients_count <= 0)
2081 {
2082 /* The function moan_smtp_batch() does not return. */
2083 if (sender_address == NULL)
2084 moan_smtp_batch(smtp_cmd_buffer,
2085 "503 MAIL FROM:<sender> command must precede DATA");
2086 else
2087 moan_smtp_batch(smtp_cmd_buffer,
2088 "503 RCPT TO:<recipient> must precede DATA");
2089 }
2090 else
2091 {
2092 done = 3; /* DATA successfully achieved */
2093 message_ended = END_NOTENDED; /* Indicate in middle of message */
2094 }
2095 break;
2096
2097
2098 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2099
2100 case VRFY_CMD:
2101 case EXPN_CMD:
2102 case HELP_CMD:
2103 case NOOP_CMD:
2104 case ETRN_CMD:
2105 bsmtp_transaction_linecount = receive_linecount;
2106 break;
2107
2108
2109 case EOF_CMD:
2110 case QUIT_CMD:
2111 done = 2;
2112 break;
2113
2114
2115 case BADARG_CMD:
2116 /* The function moan_smtp_batch() does not return. */
2117 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2118 break;
2119
2120
2121 case BADCHAR_CMD:
2122 /* The function moan_smtp_batch() does not return. */
2123 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2124 break;
2125
2126
2127 default:
2128 /* The function moan_smtp_batch() does not return. */
2129 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2130 break;
2131 }
2132 }
2133
2134 return done - 2; /* Convert yield values */
2135 }
2136
2137
2138
2139
2140 /*************************************************
2141 * Start an SMTP session *
2142 *************************************************/
2143
2144 /* This function is called at the start of an SMTP session. Thereafter,
2145 smtp_setup_msg() is called to initiate each separate message. This
2146 function does host-specific testing, and outputs the banner line.
2147
2148 Arguments: none
2149 Returns: FALSE if the session can not continue; something has
2150 gone wrong, or the connection to the host is blocked
2151 */
2152
2153 BOOL
2154 smtp_start_session(void)
2155 {
2156 int size = 256;
2157 int ptr, esclen;
2158 uschar *user_msg, *log_msg;
2159 uschar *code, *esc;
2160 uschar *p, *s, *ss;
2161
2162 smtp_connection_start = time(NULL);
2163 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2164 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2165 smtp_ch_index = 0;
2166
2167 /* Default values for certain variables */
2168
2169 helo_seen = esmtp = helo_accept_junk = FALSE;
2170 smtp_mailcmd_count = 0;
2171 count_nonmail = TRUE_UNSET;
2172 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2173 smtp_delay_mail = smtp_rlm_base;
2174 auth_advertised = FALSE;
2175 pipelining_advertised = FALSE;
2176 pipelining_enable = TRUE;
2177 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2178 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2179
2180 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2181 authentication settings from -oMaa to remain in force. */
2182
2183 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2184 authenticated_by = NULL;
2185
2186 #ifdef SUPPORT_TLS
2187 tls_in.cipher = tls_in.peerdn = NULL;
2188 tls_in.ourcert = tls_in.peercert = NULL;
2189 tls_in.sni = NULL;
2190 tls_in.ocsp = OCSP_NOT_REQ;
2191 tls_advertised = FALSE;
2192 #endif
2193 dsn_advertised = FALSE;
2194 #ifdef SUPPORT_I18N
2195 smtputf8_advertised = FALSE;
2196 #endif
2197
2198 /* Reset ACL connection variables */
2199
2200 acl_var_c = NULL;
2201
2202 /* Allow for trailing 0 in the command and data buffers. */
2203
2204 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2205 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2206 "malloc() failed for SMTP command buffer");
2207
2208 smtp_cmd_buffer[0] = 0;
2209 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2210
2211 /* For batched input, the protocol setting can be overridden from the
2212 command line by a trusted caller. */
2213
2214 if (smtp_batched_input)
2215 {
2216 if (!received_protocol) received_protocol = US"local-bsmtp";
2217 }
2218
2219 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2220 reset later if any of EHLO/AUTH/STARTTLS are received. */
2221
2222 else
2223 received_protocol =
2224 (sender_host_address ? protocols : protocols_local) [pnormal];
2225
2226 /* Set up the buffer for inputting using direct read() calls, and arrange to
2227 call the local functions instead of the standard C ones. */
2228
2229 if (!(smtp_inbuffer = (uschar *)malloc(IN_BUFFER_SIZE)))
2230 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2231
2232 receive_getc = smtp_getc;
2233 receive_get_cache = smtp_get_cache;
2234 receive_ungetc = smtp_ungetc;
2235 receive_feof = smtp_feof;
2236 receive_ferror = smtp_ferror;
2237 receive_smtp_buffered = smtp_buffered;
2238 smtp_inptr = smtp_inend = smtp_inbuffer;
2239 smtp_had_eof = smtp_had_error = 0;
2240
2241 /* Set up the message size limit; this may be host-specific */
2242
2243 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2244 if (expand_string_message != NULL)
2245 {
2246 if (thismessage_size_limit == -1)
2247 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2248 "%s", expand_string_message);
2249 else
2250 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2251 "%s", expand_string_message);
2252 smtp_closedown(US"Temporary local problem - please try later");
2253 return FALSE;
2254 }
2255
2256 /* When a message is input locally via the -bs or -bS options, sender_host_
2257 unknown is set unless -oMa was used to force an IP address, in which case it
2258 is checked like a real remote connection. When -bs is used from inetd, this
2259 flag is not set, causing the sending host to be checked. The code that deals
2260 with IP source routing (if configured) is never required for -bs or -bS and
2261 the flag sender_host_notsocket is used to suppress it.
2262
2263 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2264 reserve for certain hosts and/or networks. */
2265
2266 if (!sender_host_unknown)
2267 {
2268 int rc;
2269 BOOL reserved_host = FALSE;
2270
2271 /* Look up IP options (source routing info) on the socket if this is not an
2272 -oMa "host", and if any are found, log them and drop the connection.
2273
2274 Linux (and others now, see below) is different to everyone else, so there
2275 has to be some conditional compilation here. Versions of Linux before 2.1.15
2276 used a structure whose name was "options". Somebody finally realized that
2277 this name was silly, and it got changed to "ip_options". I use the
2278 newer name here, but there is a fudge in the script that sets up os.h
2279 to define a macro in older Linux systems.
2280
2281 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2282 glibc 2, which has chosen ip_opts for the structure name. This is now
2283 really a glibc thing rather than a Linux thing, so the condition name
2284 has been changed to reflect this. It is relevant also to GNU/Hurd.
2285
2286 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2287 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2288 a special macro defined in the os.h file.
2289
2290 Some DGUX versions on older hardware appear not to support IP options at
2291 all, so there is now a general macro which can be set to cut out this
2292 support altogether.
2293
2294 How to do this properly in IPv6 is not yet known. */
2295
2296 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2297
2298 #ifdef GLIBC_IP_OPTIONS
2299 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2300 #define OPTSTYLE 1
2301 #else
2302 #define OPTSTYLE 2
2303 #endif
2304 #elif defined DARWIN_IP_OPTIONS
2305 #define OPTSTYLE 2
2306 #else
2307 #define OPTSTYLE 3
2308 #endif
2309
2310 if (!host_checking && !sender_host_notsocket)
2311 {
2312 #if OPTSTYLE == 1
2313 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2314 struct ip_options *ipopt = store_get(optlen);
2315 #elif OPTSTYLE == 2
2316 struct ip_opts ipoptblock;
2317 struct ip_opts *ipopt = &ipoptblock;
2318 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2319 #else
2320 struct ipoption ipoptblock;
2321 struct ipoption *ipopt = &ipoptblock;
2322 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2323 #endif
2324
2325 /* Occasional genuine failures of getsockopt() have been seen - for
2326 example, "reset by peer". Therefore, just log and give up on this
2327 call, unless the error is ENOPROTOOPT. This error is given by systems
2328 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2329 of writing. So for that error, carry on - we just can't do an IP options
2330 check. */
2331
2332 DEBUG(D_receive) debug_printf("checking for IP options\n");
2333
2334 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2335 &optlen) < 0)
2336 {
2337 if (errno != ENOPROTOOPT)
2338 {
2339 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2340 host_and_ident(FALSE), strerror(errno));
2341 smtp_printf("451 SMTP service not available\r\n");
2342 return FALSE;
2343 }
2344 }
2345
2346 /* Deal with any IP options that are set. On the systems I have looked at,
2347 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2348 more logging data than will fit in big_buffer. Nevertheless, after somebody
2349 questioned this code, I've added in some paranoid checking. */
2350
2351 else if (optlen > 0)
2352 {
2353 uschar *p = big_buffer;
2354 uschar *pend = big_buffer + big_buffer_size;
2355 uschar *opt, *adptr;
2356 int optcount;
2357 struct in_addr addr;
2358
2359 #if OPTSTYLE == 1
2360 uschar *optstart = (uschar *)(ipopt->__data);
2361 #elif OPTSTYLE == 2
2362 uschar *optstart = (uschar *)(ipopt->ip_opts);
2363 #else
2364 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2365 #endif
2366
2367 DEBUG(D_receive) debug_printf("IP options exist\n");
2368
2369 Ustrcpy(p, "IP options on incoming call:");
2370 p += Ustrlen(p);
2371
2372 for (opt = optstart; opt != NULL &&
2373 opt < (uschar *)(ipopt) + optlen;)
2374 {
2375 switch (*opt)
2376 {
2377 case IPOPT_EOL:
2378 opt = NULL;
2379 break;
2380
2381 case IPOPT_NOP:
2382 opt++;
2383 break;
2384
2385 case IPOPT_SSRR:
2386 case IPOPT_LSRR:
2387 if (!string_format(p, pend-p, " %s [@%s",
2388 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2389 #if OPTSTYLE == 1
2390 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2391 #elif OPTSTYLE == 2
2392 inet_ntoa(ipopt->ip_dst)))
2393 #else
2394 inet_ntoa(ipopt->ipopt_dst)))
2395 #endif
2396 {
2397 opt = NULL;
2398 break;
2399 }
2400
2401 p += Ustrlen(p);
2402 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2403 adptr = opt + 3;
2404 while (optcount-- > 0)
2405 {
2406 memcpy(&addr, adptr, sizeof(addr));
2407 if (!string_format(p, pend - p - 1, "%s%s",
2408 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2409 {
2410 opt = NULL;
2411 break;
2412 }
2413 p += Ustrlen(p);
2414 adptr += sizeof(struct in_addr);
2415 }
2416 *p++ = ']';
2417 opt += opt[1];
2418 break;
2419
2420 default:
2421 {
2422 int i;
2423 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2424 Ustrcat(p, "[ ");
2425 p += 2;
2426 for (i = 0; i < opt[1]; i++)
2427 {
2428 sprintf(CS p, "%2.2x ", opt[i]);
2429 p += 3;
2430 }
2431 *p++ = ']';
2432 }
2433 opt += opt[1];
2434 break;
2435 }
2436 }
2437
2438 *p = 0;
2439 log_write(0, LOG_MAIN, "%s", big_buffer);
2440
2441 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2442
2443 log_write(0, LOG_MAIN|LOG_REJECT,
2444 "connection from %s refused (IP options)", host_and_ident(FALSE));
2445
2446 smtp_printf("554 SMTP service not available\r\n");
2447 return FALSE;
2448 }
2449
2450 /* Length of options = 0 => there are no options */
2451
2452 else DEBUG(D_receive) debug_printf("no IP options found\n");
2453 }
2454 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2455
2456 /* Set keep-alive in socket options. The option is on by default. This
2457 setting is an attempt to get rid of some hanging connections that stick in
2458 read() when the remote end (usually a dialup) goes away. */
2459
2460 if (smtp_accept_keepalive && !sender_host_notsocket)
2461 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2462
2463 /* If the current host matches host_lookup, set the name by doing a
2464 reverse lookup. On failure, sender_host_name will be NULL and
2465 host_lookup_failed will be TRUE. This may or may not be serious - optional
2466 checks later. */
2467
2468 if (verify_check_host(&host_lookup) == OK)
2469 {
2470 (void)host_name_lookup();
2471 host_build_sender_fullhost();
2472 }
2473
2474 /* Delay this until we have the full name, if it is looked up. */
2475
2476 set_process_info("handling incoming connection from %s",
2477 host_and_ident(FALSE));
2478
2479 /* Expand smtp_receive_timeout, if needed */
2480
2481 if (smtp_receive_timeout_s)
2482 {
2483 uschar * exp;
2484 if ( !(exp = expand_string(smtp_receive_timeout_s))
2485 || !(*exp)
2486 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2487 )
2488 log_write(0, LOG_MAIN|LOG_PANIC,
2489 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2490 }
2491
2492 /* Test for explicit connection rejection */
2493
2494 if (verify_check_host(&host_reject_connection) == OK)
2495 {
2496 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2497 "from %s (host_reject_connection)", host_and_ident(FALSE));
2498 smtp_printf("554 SMTP service not available\r\n");
2499 return FALSE;
2500 }
2501
2502 /* Test with TCP Wrappers if so configured. There is a problem in that
2503 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2504 such as disks dying. In these cases, it is desirable to reject with a 4xx
2505 error instead of a 5xx error. There isn't a "right" way to detect such
2506 problems. The following kludge is used: errno is zeroed before calling
2507 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2508 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2509 not exist). */
2510
2511 #ifdef USE_TCP_WRAPPERS
2512 errno = 0;
2513 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2514 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2515 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2516 expand_string_message);
2517
2518 if (!hosts_ctl(tcp_wrappers_name,
2519 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2520 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2521 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2522 {
2523 if (errno == 0 || errno == ENOENT)
2524 {
2525 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2526 log_write(L_connection_reject,
2527 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2528 "(tcp wrappers)", host_and_ident(FALSE));
2529 smtp_printf("554 SMTP service not available\r\n");
2530 }
2531 else
2532 {
2533 int save_errno = errno;
2534 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2535 "errno value %d\n", save_errno);
2536 log_write(L_connection_reject,
2537 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2538 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2539 smtp_printf("451 Temporary local problem - please try later\r\n");
2540 }
2541 return FALSE;
2542 }
2543 #endif
2544
2545 /* Check for reserved slots. The value of smtp_accept_count has already been
2546 incremented to include this process. */
2547
2548 if (smtp_accept_max > 0 &&
2549 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2550 {
2551 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2552 {
2553 log_write(L_connection_reject,
2554 LOG_MAIN, "temporarily refused connection from %s: not in "
2555 "reserve list: connected=%d max=%d reserve=%d%s",
2556 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2557 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2558 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2559 "please try again later\r\n", smtp_active_hostname);
2560 return FALSE;
2561 }
2562 reserved_host = TRUE;
2563 }
2564
2565 /* If a load level above which only messages from reserved hosts are
2566 accepted is set, check the load. For incoming calls via the daemon, the
2567 check is done in the superior process if there are no reserved hosts, to
2568 save a fork. In all cases, the load average will already be available
2569 in a global variable at this point. */
2570
2571 if (smtp_load_reserve >= 0 &&
2572 load_average > smtp_load_reserve &&
2573 !reserved_host &&
2574 verify_check_host(&smtp_reserve_hosts) != OK)
2575 {
2576 log_write(L_connection_reject,
2577 LOG_MAIN, "temporarily refused connection from %s: not in "
2578 "reserve list and load average = %.2f", host_and_ident(FALSE),
2579 (double)load_average/1000.0);
2580 smtp_printf("421 %s: Too much load; please try again later\r\n",
2581 smtp_active_hostname);
2582 return FALSE;
2583 }
2584
2585 /* Determine whether unqualified senders or recipients are permitted
2586 for this host. Unfortunately, we have to do this every time, in order to
2587 set the flags so that they can be inspected when considering qualifying
2588 addresses in the headers. For a site that permits no qualification, this
2589 won't take long, however. */
2590
2591 allow_unqualified_sender =
2592 verify_check_host(&sender_unqualified_hosts) == OK;
2593
2594 allow_unqualified_recipient =
2595 verify_check_host(&recipient_unqualified_hosts) == OK;
2596
2597 /* Determine whether HELO/EHLO is required for this host. The requirement
2598 can be hard or soft. */
2599
2600 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2601 if (!helo_required)
2602 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2603
2604 /* Determine whether this hosts is permitted to send syntactic junk
2605 after a HELO or EHLO command. */
2606
2607 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2608 }
2609
2610 /* For batch SMTP input we are now done. */
2611
2612 if (smtp_batched_input) return TRUE;
2613
2614 /* If valid Proxy Protocol source is connecting, set up session.
2615 * Failure will not allow any SMTP function other than QUIT. */
2616
2617 #ifdef SUPPORT_PROXY
2618 proxy_session = FALSE;
2619 proxy_session_failed = FALSE;
2620 if (check_proxy_protocol_host())
2621 setup_proxy_protocol_host();
2622 #endif
2623
2624 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2625 smtps port for use with older style SSL MTAs. */
2626
2627 #ifdef SUPPORT_TLS
2628 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2629 return FALSE;
2630 #endif
2631
2632 /* Run the connect ACL if it exists */
2633
2634 user_msg = NULL;
2635 if (acl_smtp_connect)
2636 {
2637 int rc;
2638 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2639 &log_msg)) != OK)
2640 {
2641 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2642 return FALSE;
2643 }
2644 }
2645
2646 /* Output the initial message for a two-way SMTP connection. It may contain
2647 newlines, which then cause a multi-line response to be given. */
2648
2649 code = US"220"; /* Default status code */
2650 esc = US""; /* Default extended status code */
2651 esclen = 0; /* Length of esc */
2652
2653 if (!user_msg)
2654 {
2655 if (!(s = expand_string(smtp_banner)))
2656 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2657 "failed: %s", smtp_banner, expand_string_message);
2658 }
2659 else
2660 {
2661 int codelen = 3;
2662 s = user_msg;
2663 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2664 if (codelen > 4)
2665 {
2666 esc = code + 4;
2667 esclen = codelen - 4;
2668 }
2669 }
2670
2671 /* Remove any terminating newlines; might as well remove trailing space too */
2672
2673 p = s + Ustrlen(s);
2674 while (p > s && isspace(p[-1])) p--;
2675 *p = 0;
2676
2677 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2678 is all contained in a single IP packet. The original code wrote out the
2679 greeting using several calls to fprint/fputc, and on busy servers this could
2680 cause it to be split over more than one packet - which caused CC:Mail to fall
2681 over when it got the second part of the greeting after sending its first
2682 command. Sigh. To try to avoid this, build the complete greeting message
2683 first, and output it in one fell swoop. This gives a better chance of it
2684 ending up as a single packet. */
2685
2686 ss = store_get(size);
2687 ptr = 0;
2688
2689 p = s;
2690 do /* At least once, in case we have an empty string */
2691 {
2692 int len;
2693 uschar *linebreak = Ustrchr(p, '\n');
2694 ss = string_catn(ss, &size, &ptr, code, 3);
2695 if (linebreak == NULL)
2696 {
2697 len = Ustrlen(p);
2698 ss = string_catn(ss, &size, &ptr, US" ", 1);
2699 }
2700 else
2701 {
2702 len = linebreak - p;
2703 ss = string_catn(ss, &size, &ptr, US"-", 1);
2704 }
2705 ss = string_catn(ss, &size, &ptr, esc, esclen);
2706 ss = string_catn(ss, &size, &ptr, p, len);
2707 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2708 p += len;
2709 if (linebreak != NULL) p++;
2710 }
2711 while (*p != 0);
2712
2713 ss[ptr] = 0; /* string_cat leaves room for this */
2714
2715 /* Before we write the banner, check that there is no input pending, unless
2716 this synchronisation check is disabled. */
2717
2718 if (!check_sync())
2719 {
2720 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2721 "synchronization error (input sent without waiting for greeting): "
2722 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2723 string_printing(smtp_inptr));
2724 smtp_printf("554 SMTP synchronization error\r\n");
2725 return FALSE;
2726 }
2727
2728 /* Now output the banner */
2729
2730 smtp_printf("%s", ss);
2731 return TRUE;
2732 }
2733
2734
2735
2736
2737
2738 /*************************************************
2739 * Handle SMTP syntax and protocol errors *
2740 *************************************************/
2741
2742 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2743 to do so. Then transmit the error response. The return value depends on the
2744 number of syntax and protocol errors in this SMTP session.
2745
2746 Arguments:
2747 type error type, given as a log flag bit
2748 code response code; <= 0 means don't send a response
2749 data data to reflect in the response (can be NULL)
2750 errmess the error message
2751
2752 Returns: -1 limit of syntax/protocol errors NOT exceeded
2753 +1 limit of syntax/protocol errors IS exceeded
2754
2755 These values fit in with the values of the "done" variable in the main
2756 processing loop in smtp_setup_msg(). */
2757
2758 static int
2759 synprot_error(int type, int code, uschar *data, uschar *errmess)
2760 {
2761 int yield = -1;
2762
2763 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2764 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2765 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2766
2767 if (++synprot_error_count > smtp_max_synprot_errors)
2768 {
2769 yield = 1;
2770 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2771 "syntax or protocol errors (last command was \"%s\")",
2772 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2773 }
2774
2775 if (code > 0)
2776 {
2777 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2778 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2779 if (yield == 1)
2780 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2781 }
2782
2783 return yield;
2784 }
2785
2786
2787
2788
2789 /*************************************************
2790 * Send SMTP response, possibly multiline *
2791 *************************************************/
2792
2793 /* There are, it seems, broken clients out there that cannot handle multiline
2794 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2795 output nothing for non-final calls, and only the first line for anything else.
2796
2797 Arguments:
2798 code SMTP code, may involve extended status codes
2799 codelen length of smtp code; if > 4 there's an ESC
2800 final FALSE if the last line isn't the final line
2801 msg message text, possibly containing newlines
2802
2803 Returns: nothing
2804 */
2805
2806 void
2807 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2808 {
2809 int esclen = 0;
2810 uschar *esc = US"";
2811
2812 if (!final && no_multiline_responses) return;
2813
2814 if (codelen > 4)
2815 {
2816 esc = code + 4;
2817 esclen = codelen - 4;
2818 }
2819
2820 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2821 have had the same. Note: this code is also present in smtp_printf(). It would
2822 be tidier to have it only in one place, but when it was added, it was easier to
2823 do it that way, so as not to have to mess with the code for the RCPT command,
2824 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2825
2826 if (rcpt_in_progress)
2827 {
2828 if (rcpt_smtp_response == NULL)
2829 rcpt_smtp_response = string_copy(msg);
2830 else if (rcpt_smtp_response_same &&
2831 Ustrcmp(rcpt_smtp_response, msg) != 0)
2832 rcpt_smtp_response_same = FALSE;
2833 rcpt_in_progress = FALSE;
2834 }
2835
2836 /* Not output the message, splitting it up into multiple lines if necessary. */
2837
2838 for (;;)
2839 {
2840 uschar *nl = Ustrchr(msg, '\n');
2841 if (nl == NULL)
2842 {
2843 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2844 return;
2845 }
2846 else if (nl[1] == 0 || no_multiline_responses)
2847 {
2848 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2849 (int)(nl - msg), msg);
2850 return;
2851 }
2852 else
2853 {
2854 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2855 msg = nl + 1;
2856 while (isspace(*msg)) msg++;
2857 }
2858 }
2859 }
2860
2861
2862
2863
2864 /*************************************************
2865 * Parse user SMTP message *
2866 *************************************************/
2867
2868 /* This function allows for user messages overriding the response code details
2869 by providing a suitable response code string at the start of the message
2870 user_msg. Check the message for starting with a response code and optionally an
2871 extended status code. If found, check that the first digit is valid, and if so,
2872 change the code pointer and length to use the replacement. An invalid code
2873 causes a panic log; in this case, if the log messages is the same as the user
2874 message, we must also adjust the value of the log message to show the code that
2875 is actually going to be used (the original one).
2876
2877 This function is global because it is called from receive.c as well as within
2878 this module.
2879
2880 Note that the code length returned includes the terminating whitespace
2881 character, which is always included in the regex match.
2882
2883 Arguments:
2884 code SMTP code, may involve extended status codes
2885 codelen length of smtp code; if > 4 there's an ESC
2886 msg message text
2887 log_msg optional log message, to be adjusted with the new SMTP code
2888 check_valid if true, verify the response code
2889
2890 Returns: nothing
2891 */
2892
2893 void
2894 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2895 BOOL check_valid)
2896 {
2897 int n;
2898 int ovector[3];
2899
2900 if (!msg || !*msg) return;
2901
2902 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2903 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
2904
2905 if (check_valid && (*msg)[0] != (*code)[0])
2906 {
2907 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2908 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2909 if (log_msg != NULL && *log_msg == *msg)
2910 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2911 }
2912 else
2913 {
2914 *code = *msg;
2915 *codelen = ovector[1]; /* Includes final space */
2916 }
2917 *msg += ovector[1]; /* Chop the code off the message */
2918 return;
2919 }
2920
2921
2922
2923
2924 /*************************************************
2925 * Handle an ACL failure *
2926 *************************************************/
2927
2928 /* This function is called when acl_check() fails. As well as calls from within
2929 this module, it is called from receive.c for an ACL after DATA. It sorts out
2930 logging the incident, and sets up the error response. A message containing
2931 newlines is turned into a multiline SMTP response, but for logging, only the
2932 first line is used.
2933
2934 There's a table of default permanent failure response codes to use in
2935 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2936 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2937 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2938 state, because there are broken clients that try VRFY before RCPT. A 5xx
2939 response should be given only when the address is positively known to be
2940 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2941 no explicit code, but if there is one we let it know best.
2942 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2943
2944 From Exim 4.63, it is possible to override the response code details by
2945 providing a suitable response code string at the start of the message provided
2946 in user_msg. The code's first digit is checked for validity.
2947
2948 Arguments:
2949 where where the ACL was called from
2950 rc the failure code
2951 user_msg a message that can be included in an SMTP response
2952 log_msg a message for logging
2953
2954 Returns: 0 in most cases
2955 2 if the failure code was FAIL_DROP, in which case the
2956 SMTP connection should be dropped (this value fits with the
2957 "done" variable in smtp_setup_msg() below)
2958 */
2959
2960 int
2961 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2962 {
2963 BOOL drop = rc == FAIL_DROP;
2964 int codelen = 3;
2965 uschar *smtp_code;
2966 uschar *lognl;
2967 uschar *sender_info = US"";
2968 uschar *what =
2969 #ifdef WITH_CONTENT_SCAN
2970 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
2971 #endif
2972 where == ACL_WHERE_PREDATA ? US"DATA" :
2973 where == ACL_WHERE_DATA ? US"after DATA" :
2974 #ifndef DISABLE_PRDR
2975 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
2976 #endif
2977 smtp_cmd_data ?
2978 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
2979 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
2980
2981 if (drop) rc = FAIL;
2982
2983 /* Set the default SMTP code, and allow a user message to change it. */
2984
2985 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2986 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2987 where != ACL_WHERE_VRFY);
2988
2989 /* We used to have sender_address here; however, there was a bug that was not
2990 updating sender_address after a rewrite during a verify. When this bug was
2991 fixed, sender_address at this point became the rewritten address. I'm not sure
2992 this is what should be logged, so I've changed to logging the unrewritten
2993 address to retain backward compatibility. */
2994
2995 #ifndef WITH_CONTENT_SCAN
2996 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2997 #else
2998 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2999 #endif
3000 {
3001 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3002 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3003 sender_host_authenticated ? US" A=" : US"",
3004 sender_host_authenticated ? sender_host_authenticated : US"",
3005 sender_host_authenticated && authenticated_id ? US":" : US"",
3006 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3007 );
3008 }
3009
3010 /* If there's been a sender verification failure with a specific message, and
3011 we have not sent a response about it yet, do so now, as a preliminary line for
3012 failures, but not defers. However, always log it for defer, and log it for fail
3013 unless the sender_verify_fail log selector has been turned off. */
3014
3015 if (sender_verified_failed &&
3016 !testflag(sender_verified_failed, af_sverify_told))
3017 {
3018 BOOL save_rcpt_in_progress = rcpt_in_progress;
3019 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3020
3021 setflag(sender_verified_failed, af_sverify_told);
3022
3023 if (rc != FAIL || LOGGING(sender_verify_fail))
3024 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3025 host_and_ident(TRUE),
3026 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3027 sender_verified_failed->address,
3028 (sender_verified_failed->message == NULL)? US"" :
3029 string_sprintf(": %s", sender_verified_failed->message));
3030
3031 if (rc == FAIL && sender_verified_failed->user_message)
3032 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3033 testflag(sender_verified_failed, af_verify_pmfail)?
3034 "Postmaster verification failed while checking <%s>\n%s\n"
3035 "Several RFCs state that you are required to have a postmaster\n"
3036 "mailbox for each mail domain. This host does not accept mail\n"
3037 "from domains whose servers reject the postmaster address."
3038 :
3039 testflag(sender_verified_failed, af_verify_nsfail)?
3040 "Callback setup failed while verifying <%s>\n%s\n"
3041 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3042 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3043 "RFC requirements, and stops you from receiving standard bounce\n"
3044 "messages. This host does not accept mail from domains whose servers\n"
3045 "refuse bounces."
3046 :
3047 "Verification failed for <%s>\n%s",
3048 sender_verified_failed->address,
3049 sender_verified_failed->user_message));
3050
3051 rcpt_in_progress = save_rcpt_in_progress;
3052 }
3053
3054 /* Sort out text for logging */
3055
3056 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3057 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3058
3059 /* Send permanent failure response to the command, but the code used isn't
3060 always a 5xx one - see comments at the start of this function. If the original
3061 rc was FAIL_DROP we drop the connection and yield 2. */
3062
3063 if (rc == FAIL)
3064 smtp_respond(smtp_code, codelen, TRUE,
3065 user_msg ? user_msg : US"Administrative prohibition");
3066
3067 /* Send temporary failure response to the command. Don't give any details,
3068 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3069 verb, and for a header verify when smtp_return_error_details is set.
3070
3071 This conditional logic is all somewhat of a mess because of the odd
3072 interactions between temp_details and return_error_details. One day it should
3073 be re-implemented in a tidier fashion. */
3074
3075 else
3076 if (acl_temp_details && user_msg)
3077 {
3078 if ( smtp_return_error_details
3079 && sender_verified_failed
3080 && sender_verified_failed->message
3081 )
3082 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3083
3084 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3085 }
3086 else
3087 smtp_respond(smtp_code, codelen, TRUE,
3088 US"Temporary local problem - please try later");
3089
3090 /* Log the incident to the logs that are specified by log_reject_target
3091 (default main, reject). This can be empty to suppress logging of rejections. If
3092 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3093 is closing if required and return 2. */
3094
3095 if (log_reject_target != 0)
3096 {
3097 #ifdef SUPPORT_TLS
3098 uschar * tls = s_tlslog(NULL, NULL, NULL);
3099 if (!tls) tls = US"";
3100 #else
3101 uschar * tls = US"";
3102 #endif
3103 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3104 log_reject_target, "%s%s%s %s%srejected %s%s",
3105 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3106 host_and_ident(TRUE),
3107 tls,
3108 sender_info,
3109 rc == FAIL ? US"" : US"temporarily ",
3110 what, log_msg);
3111 }
3112
3113 if (!drop) return 0;
3114
3115 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3116 smtp_get_connection_info());
3117
3118 /* Run the not-quit ACL, but without any custom messages. This should not be a
3119 problem, because we get here only if some other ACL has issued "drop", and
3120 in that case, *its* custom messages will have been used above. */
3121
3122 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3123 return 2;
3124 }
3125
3126
3127
3128
3129 /*************************************************
3130 * Handle SMTP exit when QUIT is not given *
3131 *************************************************/
3132
3133 /* This function provides a logging/statistics hook for when an SMTP connection
3134 is dropped on the floor or the other end goes away. It's a global function
3135 because it's called from receive.c as well as this module. As well as running
3136 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3137 response, either with a custom message from the ACL, or using a default. There
3138 is one case, however, when no message is output - after "drop". In that case,
3139 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3140 passed to this function.
3141
3142 In case things go wrong while processing this function, causing an error that
3143 may re-enter this function, there is a recursion check.
3144
3145 Arguments:
3146 reason What $smtp_notquit_reason will be set to in the ACL;
3147 if NULL, the ACL is not run
3148 code The error code to return as part of the response
3149 defaultrespond The default message if there's no user_msg
3150
3151 Returns: Nothing
3152 */
3153
3154 void
3155 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3156 {
3157 int rc;
3158 uschar *user_msg = NULL;
3159 uschar *log_msg = NULL;
3160
3161 /* Check for recursive acll */
3162
3163 if (smtp_exit_function_called)
3164 {
3165 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3166 reason);
3167 return;
3168 }
3169 smtp_exit_function_called = TRUE;
3170
3171 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3172
3173 if (acl_smtp_notquit && reason)
3174 {
3175 smtp_notquit_reason = reason;
3176 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3177 &log_msg)) == ERROR)
3178 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3179 log_msg);
3180 }
3181
3182 /* Write an SMTP response if we are expected to give one. As the default
3183 responses are all internal, they should always fit in the buffer, but code a
3184 warning, just in case. Note that string_vformat() still leaves a complete
3185 string, even if it is incomplete. */
3186
3187 if (code && defaultrespond)
3188 {
3189 if (user_msg)
3190 smtp_respond(code, 3, TRUE, user_msg);
3191 else
3192 {
3193 uschar buffer[128];
3194 va_list ap;
3195 va_start(ap, defaultrespond);
3196 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3197 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3198 smtp_printf("%s %s\r\n", code, buffer);
3199 va_end(ap);
3200 }
3201 mac_smtp_fflush();
3202 }
3203 }
3204
3205
3206
3207
3208 /*************************************************
3209 * Verify HELO argument *
3210 *************************************************/
3211
3212 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3213 matched. It is also called from ACL processing if verify = helo is used and
3214 verification was not previously tried (i.e. helo_try_verify_hosts was not
3215 matched). The result of its processing is to set helo_verified and
3216 helo_verify_failed. These variables should both be FALSE for this function to
3217 be called.
3218
3219 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3220 for IPv6 ::ffff: literals.
3221
3222 Argument: none
3223 Returns: TRUE if testing was completed;
3224 FALSE on a temporary failure
3225 */
3226
3227 BOOL
3228 smtp_verify_helo(void)
3229 {
3230 BOOL yield = TRUE;
3231
3232 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3233 sender_helo_name);
3234
3235 if (sender_helo_name == NULL)
3236 {
3237 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3238 }
3239
3240 /* Deal with the case of -bs without an IP address */
3241
3242 else if (sender_host_address == NULL)
3243 {
3244 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3245 helo_verified = TRUE;
3246 }
3247
3248 /* Deal with the more common case when there is a sending IP address */
3249
3250 else if (sender_helo_name[0] == '[')
3251 {
3252 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3253 Ustrlen(sender_host_address)) == 0;
3254
3255 #if HAVE_IPV6
3256 if (!helo_verified)
3257 {
3258 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3259 helo_verified = Ustrncmp(sender_helo_name + 1,
3260 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3261 }
3262 #endif
3263
3264 HDEBUG(D_receive)
3265 { if (helo_verified) debug_printf("matched host address\n"); }
3266 }
3267
3268 /* Do a reverse lookup if one hasn't already given a positive or negative
3269 response. If that fails, or the name doesn't match, try checking with a forward
3270 lookup. */
3271
3272 else
3273 {
3274 if (sender_host_name == NULL && !host_lookup_failed)
3275 yield = host_name_lookup() != DEFER;
3276
3277 /* If a host name is known, check it and all its aliases. */
3278
3279 if (sender_host_name)
3280 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3281 {
3282 sender_helo_dnssec = sender_host_dnssec;
3283 HDEBUG(D_receive) debug_printf("matched host name\n");
3284 }
3285 else
3286 {
3287 uschar **aliases = sender_host_aliases;
3288 while (*aliases)
3289 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3290 {
3291 sender_helo_dnssec = sender_host_dnssec;
3292 break;
3293 }
3294
3295 HDEBUG(D_receive) if (helo_verified)
3296 debug_printf("matched alias %s\n", *(--aliases));
3297 }
3298
3299 /* Final attempt: try a forward lookup of the helo name */
3300
3301 if (!helo_verified)
3302 {
3303 int rc;
3304 host_item h;
3305 dnssec_domains d;
3306 host_item *hh;
3307
3308 h.name = sender_helo_name;
3309 h.address = NULL;
3310 h.mx = MX_NONE;
3311 h.next = NULL;
3312 d.request = US"*";
3313 d.require = US"";
3314
3315 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3316 sender_helo_name);
3317 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3318 NULL, NULL, NULL, &d, NULL, NULL);
3319 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3320 for (hh = &h; hh; hh = hh->next)
3321 if (Ustrcmp(hh->address, sender_host_address) == 0)
3322 {
3323 helo_verified = TRUE;
3324 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3325 HDEBUG(D_receive)
3326 {
3327 debug_printf("IP address for %s matches calling address\n"
3328 "Forward DNS security status: %sverified\n",
3329 sender_helo_name, sender_helo_dnssec ? "" : "un");
3330 }
3331 break;
3332 }
3333 }
3334 }
3335
3336 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3337 return yield;
3338 }
3339
3340
3341
3342
3343 /*************************************************
3344 * Send user response message *
3345 *************************************************/
3346
3347 /* This function is passed a default response code and a user message. It calls
3348 smtp_message_code() to check and possibly modify the response code, and then
3349 calls smtp_respond() to transmit the response. I put this into a function
3350 just to avoid a lot of repetition.
3351
3352 Arguments:
3353 code the response code
3354 user_msg the user message
3355
3356 Returns: nothing
3357 */
3358
3359 static void
3360 smtp_user_msg(uschar *code, uschar *user_msg)
3361 {
3362 int len = 3;
3363 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3364 smtp_respond(code, len, TRUE, user_msg);
3365 }
3366
3367
3368
3369 static int
3370 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3371 {
3372 const uschar *set_id = NULL;
3373 int rc, i;
3374
3375 /* Run the checking code, passing the remainder of the command line as
3376 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3377 it as the only set numerical variable. The authenticator may set $auth<n>
3378 and also set other numeric variables. The $auth<n> variables are preferred
3379 nowadays; the numerical variables remain for backwards compatibility.
3380
3381 Afterwards, have a go at expanding the set_id string, even if
3382 authentication failed - for bad passwords it can be useful to log the
3383 userid. On success, require set_id to expand and exist, and put it in
3384 authenticated_id. Save this in permanent store, as the working store gets
3385 reset at HELO, RSET, etc. */
3386
3387 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3388 expand_nmax = 0;
3389 expand_nlength[0] = 0; /* $0 contains nothing */
3390
3391 rc = (au->info->servercode)(au, smtp_cmd_data);
3392 if (au->set_id) set_id = expand_string(au->set_id);
3393 expand_nmax = -1; /* Reset numeric variables */
3394 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3395
3396 /* The value of authenticated_id is stored in the spool file and printed in
3397 log lines. It must not contain binary zeros or newline characters. In
3398 normal use, it never will, but when playing around or testing, this error
3399 can (did) happen. To guard against this, ensure that the id contains only
3400 printing characters. */
3401
3402 if (set_id) set_id = string_printing(set_id);
3403
3404 /* For the non-OK cases, set up additional logging data if set_id
3405 is not empty. */
3406
3407 if (rc != OK)
3408 set_id = set_id && *set_id
3409 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3410
3411 /* Switch on the result */
3412
3413 switch(rc)
3414 {
3415 case OK:
3416 if (!au->set_id || set_id) /* Complete success */
3417 {
3418 if (set_id) authenticated_id = string_copy_malloc(set_id);
3419 sender_host_authenticated = au->name;
3420 authentication_failed = FALSE;
3421 authenticated_fail_id = NULL; /* Impossible to already be set? */
3422
3423 received_protocol =
3424 (sender_host_address ? protocols : protocols_local)
3425 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3426 *s = *ss = US"235 Authentication succeeded";
3427 authenticated_by = au;
3428 break;
3429 }
3430
3431 /* Authentication succeeded, but we failed to expand the set_id string.
3432 Treat this as a temporary error. */
3433
3434 auth_defer_msg = expand_string_message;
3435 /* Fall through */
3436
3437 case DEFER:
3438 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3439 *s = string_sprintf("435 Unable to authenticate at present%s",
3440 auth_defer_user_msg);
3441 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3442 set_id, auth_defer_msg);
3443 break;
3444
3445 case BAD64:
3446 *s = *ss = US"501 Invalid base64 data";
3447 break;
3448
3449 case CANCELLED:
3450 *s = *ss = US"501 Authentication cancelled";
3451 break;
3452
3453 case UNEXPECTED:
3454 *s = *ss = US"553 Initial data not expected";
3455 break;
3456
3457 case FAIL:
3458 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3459 *s = US"535 Incorrect authentication data";
3460 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3461 break;
3462
3463 default:
3464 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3465 *s = US"435 Internal error";
3466 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3467 "check", set_id, rc);
3468 break;
3469 }
3470
3471 return rc;
3472 }
3473
3474
3475
3476
3477
3478 static int
3479 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3480 {
3481 int rd;
3482 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3483 {
3484 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3485 *recipient);
3486 rd = Ustrlen(recipient) + 1;
3487 *recipient = rewrite_address_qualify(*recipient, TRUE);
3488 return rd;
3489 }
3490 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3491 smtp_cmd_data);
3492 log_write(L_smtp_syntax_error,
3493 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3494 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3495 return 0;
3496 }
3497
3498
3499
3500
3501 static void
3502 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3503 {
3504 HAD(SCH_QUIT);
3505 incomplete_transaction_log(US"QUIT");
3506