Fix DKIM verify when used with CHUNKING. Bug 2016
[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 static 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.
901
902 Arguments: none
903 Returns: bool
904 */
905
906 static BOOL
907 check_proxy_protocol_host()
908 {
909 int rc;
910 /* Cannot configure local connection as a proxy inbound */
911 if (sender_host_address == NULL) return proxy_session;
912
913 rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
914 sender_host_address, NULL);
915 if (rc == OK)
916 {
917 DEBUG(D_receive)
918 debug_printf("Detected proxy protocol configured host\n");
919 proxy_session = TRUE;
920 }
921 return proxy_session;
922 }
923
924
925 /*************************************************
926 * Setup host for proxy protocol *
927 *************************************************/
928 /* The function configures the connection based on a header from the
929 inbound host to use Proxy Protocol. The specification is very exact
930 so exit with an error if do not find the exact required pieces. This
931 includes an incorrect number of spaces separating args.
932
933 Arguments: none
934 Returns: Boolean success
935 */
936
937 static BOOL
938 setup_proxy_protocol_host()
939 {
940 union {
941 struct {
942 uschar line[108];
943 } v1;
944 struct {
945 uschar sig[12];
946 uint8_t ver_cmd;
947 uint8_t fam;
948 uint16_t len;
949 union {
950 struct { /* TCP/UDP over IPv4, len = 12 */
951 uint32_t src_addr;
952 uint32_t dst_addr;
953 uint16_t src_port;
954 uint16_t dst_port;
955 } ip4;
956 struct { /* TCP/UDP over IPv6, len = 36 */
957 uint8_t src_addr[16];
958 uint8_t dst_addr[16];
959 uint16_t src_port;
960 uint16_t dst_port;
961 } ip6;
962 struct { /* AF_UNIX sockets, len = 216 */
963 uschar src_addr[108];
964 uschar dst_addr[108];
965 } unx;
966 } addr;
967 } v2;
968 } hdr;
969
970 /* Temp variables used in PPv2 address:port parsing */
971 uint16_t tmpport;
972 char tmpip[INET_ADDRSTRLEN];
973 struct sockaddr_in tmpaddr;
974 char tmpip6[INET6_ADDRSTRLEN];
975 struct sockaddr_in6 tmpaddr6;
976
977 int get_ok = 0;
978 int size, ret;
979 int fd = fileno(smtp_in);
980 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
981 uschar *iptype; /* To display debug info */
982 struct timeval tv;
983 struct timeval tvtmp;
984 socklen_t vslen = sizeof(struct timeval);
985
986 /* Save current socket timeout values */
987 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
988
989 /* Proxy Protocol host must send header within a short time
990 (default 3 seconds) or it's considered invalid */
991 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
992 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
993 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
994 return FALSE;
995
996 do
997 {
998 /* The inbound host was declared to be a Proxy Protocol host, so
999 don't do a PEEK into the data, actually slurp it up. */
1000 ret = recv(fd, &hdr, sizeof(hdr), 0);
1001 }
1002 while (ret == -1 && errno == EINTR);
1003
1004 if (ret == -1)
1005 goto proxyfail;
1006
1007 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1008 {
1009 uint8_t ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1010 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1011
1012 /* May 2014: haproxy combined the version and command into one byte to
1013 allow two full bytes for the length field in order to proxy SSL
1014 connections. SSL Proxy is not supported in this version of Exim, but
1015 must still separate values here. */
1016
1017 if (ver != 0x02)
1018 {
1019 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1020 goto proxyfail;
1021 }
1022 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
1023 /* The v2 header will always be 16 bytes per the spec. */
1024 size = 16 + ntohs(hdr.v2.len);
1025 if (ret < size)
1026 {
1027 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
1028 ret, size);
1029 goto proxyfail;
1030 }
1031 switch (cmd)
1032 {
1033 case 0x01: /* PROXY command */
1034 switch (hdr.v2.fam)
1035 {
1036 case 0x11: /* TCPv4 address type */
1037 iptype = US"IPv4";
1038 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1039 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1040 if (!string_is_ip_address(US tmpip, NULL))
1041 {
1042 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1043 goto proxyfail;
1044 }
1045 proxy_local_address = sender_host_address;
1046 sender_host_address = string_copy(US tmpip);
1047 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1048 proxy_local_port = sender_host_port;
1049 sender_host_port = tmpport;
1050 /* Save dest ip/port */
1051 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1052 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1053 if (!string_is_ip_address(US tmpip, NULL))
1054 {
1055 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1056 goto proxyfail;
1057 }
1058 proxy_external_address = string_copy(US tmpip);
1059 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1060 proxy_external_port = tmpport;
1061 goto done;
1062 case 0x21: /* TCPv6 address type */
1063 iptype = US"IPv6";
1064 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1065 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1066 if (!string_is_ip_address(US tmpip6, NULL))
1067 {
1068 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1069 goto proxyfail;
1070 }
1071 proxy_local_address = sender_host_address;
1072 sender_host_address = string_copy(US tmpip6);
1073 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1074 proxy_local_port = sender_host_port;
1075 sender_host_port = tmpport;
1076 /* Save dest ip/port */
1077 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1078 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1079 if (!string_is_ip_address(US tmpip6, NULL))
1080 {
1081 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1082 goto proxyfail;
1083 }
1084 proxy_external_address = string_copy(US tmpip6);
1085 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1086 proxy_external_port = tmpport;
1087 goto done;
1088 default:
1089 DEBUG(D_receive)
1090 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1091 hdr.v2.fam);
1092 goto proxyfail;
1093 }
1094 /* Unsupported protocol, keep local connection address */
1095 break;
1096 case 0x00: /* LOCAL command */
1097 /* Keep local connection address for LOCAL */
1098 break;
1099 default:
1100 DEBUG(D_receive)
1101 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1102 goto proxyfail;
1103 }
1104 }
1105 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1106 {
1107 uschar *p = string_copy(hdr.v1.line);
1108 uschar *end = memchr(p, '\r', ret - 1);
1109 uschar *sp; /* Utility variables follow */
1110 int tmp_port;
1111 char *endc;
1112
1113 if (!end || end[1] != '\n')
1114 {
1115 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1116 goto proxyfail;
1117 }
1118 *end = '\0'; /* Terminate the string */
1119 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
1120 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1121 /* Step through the string looking for the required fields. Ensure
1122 strict adherence to required formatting, exit for any error. */
1123 p += 5;
1124 if (!isspace(*(p++)))
1125 {
1126 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1127 goto proxyfail;
1128 }
1129 if (!Ustrncmp(p, CCS"TCP4", 4))
1130 iptype = US"IPv4";
1131 else if (!Ustrncmp(p,CCS"TCP6", 4))
1132 iptype = US"IPv6";
1133 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1134 {
1135 iptype = US"Unknown";
1136 goto done;
1137 }
1138 else
1139 {
1140 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1141 goto proxyfail;
1142 }
1143
1144 p += Ustrlen(iptype);
1145 if (!isspace(*(p++)))
1146 {
1147 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1148 goto proxyfail;
1149 }
1150 /* Find the end of the arg */
1151 if ((sp = Ustrchr(p, ' ')) == NULL)
1152 {
1153 DEBUG(D_receive)
1154 debug_printf("Did not find proxied src %s\n", iptype);
1155 goto proxyfail;
1156 }
1157 *sp = '\0';
1158 if(!string_is_ip_address(p, NULL))
1159 {
1160 DEBUG(D_receive)
1161 debug_printf("Proxied src arg is not an %s address\n", iptype);
1162 goto proxyfail;
1163 }
1164 proxy_local_address = sender_host_address;
1165 sender_host_address = p;
1166 p = sp + 1;
1167 if ((sp = Ustrchr(p, ' ')) == NULL)
1168 {
1169 DEBUG(D_receive)
1170 debug_printf("Did not find proxy dest %s\n", iptype);
1171 goto proxyfail;
1172 }
1173 *sp = '\0';
1174 if(!string_is_ip_address(p, NULL))
1175 {
1176 DEBUG(D_receive)
1177 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1178 goto proxyfail;
1179 }
1180 proxy_external_address = p;
1181 p = sp + 1;
1182 if ((sp = Ustrchr(p, ' ')) == NULL)
1183 {
1184 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1185 goto proxyfail;
1186 }
1187 *sp = '\0';
1188 tmp_port = strtol(CCS p, &endc, 10);
1189 if (*endc || tmp_port == 0)
1190 {
1191 DEBUG(D_receive)
1192 debug_printf("Proxied src port '%s' not an integer\n", p);
1193 goto proxyfail;
1194 }
1195 proxy_local_port = sender_host_port;
1196 sender_host_port = tmp_port;
1197 p = sp + 1;
1198 if ((sp = Ustrchr(p, '\0')) == NULL)
1199 {
1200 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1201 goto proxyfail;
1202 }
1203 tmp_port = strtol(CCS p, &endc, 10);
1204 if (*endc || tmp_port == 0)
1205 {
1206 DEBUG(D_receive)
1207 debug_printf("Proxy dest port '%s' not an integer\n", p);
1208 goto proxyfail;
1209 }
1210 proxy_external_port = tmp_port;
1211 /* Already checked for /r /n above. Good V1 header received. */
1212 goto done;
1213 }
1214 else
1215 {
1216 /* Wrong protocol */
1217 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1218 goto proxyfail;
1219 }
1220
1221 proxyfail:
1222 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1223 /* Don't flush any potential buffer contents. Any input should cause a
1224 synchronization failure */
1225 return FALSE;
1226
1227 done:
1228 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1229 DEBUG(D_receive)
1230 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1231 return proxy_session;
1232 }
1233 #endif
1234
1235 /*************************************************
1236 * Read one command line *
1237 *************************************************/
1238
1239 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1240 There are sites that don't do this, and in any case internal SMTP probably
1241 should check only for LF. Consequently, we check here for LF only. The line
1242 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1243 an unknown command. The command is read into the global smtp_cmd_buffer so that
1244 it is available via $smtp_command.
1245
1246 The character reading routine sets up a timeout for each block actually read
1247 from the input (which may contain more than one command). We set up a special
1248 signal handler that closes down the session on a timeout. Control does not
1249 return when it runs.
1250
1251 Arguments:
1252 check_sync if TRUE, check synchronization rules if global option is TRUE
1253 buffer_lim maximum to buffer in lower layer
1254
1255 Returns: a code identifying the command (enumerated above)
1256 */
1257
1258 static int
1259 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1260 {
1261 int c;
1262 int ptr = 0;
1263 smtp_cmd_list *p;
1264 BOOL hadnull = FALSE;
1265
1266 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1267
1268 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1269 {
1270 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1271 {
1272 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1273 return OTHER_CMD;
1274 }
1275 if (c == 0)
1276 {
1277 hadnull = TRUE;
1278 c = '?';
1279 }
1280 smtp_cmd_buffer[ptr++] = c;
1281 }
1282
1283 receive_linecount++; /* For BSMTP errors */
1284 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1285
1286 /* If hit end of file, return pseudo EOF command. Whether we have a
1287 part-line already read doesn't matter, since this is an error state. */
1288
1289 if (c == EOF) return EOF_CMD;
1290
1291 /* Remove any CR and white space at the end of the line, and terminate the
1292 string. */
1293
1294 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1295 smtp_cmd_buffer[ptr] = 0;
1296
1297 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1298
1299 /* NULLs are not allowed in SMTP commands */
1300
1301 if (hadnull) return BADCHAR_CMD;
1302
1303 /* Scan command list and return identity, having set the data pointer
1304 to the start of the actual data characters. Check for SMTP synchronization
1305 if required. */
1306
1307 for (p = cmd_list; p < cmd_list_end; p++)
1308 {
1309 #ifdef SUPPORT_PROXY
1310 /* Only allow QUIT command if Proxy Protocol parsing failed */
1311 if (proxy_session && proxy_session_failed)
1312 {
1313 if (p->cmd != QUIT_CMD)
1314 continue;
1315 }
1316 #endif
1317 if ( p->len
1318 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1319 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1320 || smtp_cmd_buffer[p->len] == 0
1321 || smtp_cmd_buffer[p->len] == ' '
1322 ) )
1323 {
1324 if (smtp_inptr < smtp_inend && /* Outstanding input */
1325 p->cmd < sync_cmd_limit && /* Command should sync */
1326 check_sync && /* Local flag set */
1327 smtp_enforce_sync && /* Global flag set */
1328 sender_host_address != NULL && /* Not local input */
1329 !sender_host_notsocket) /* Really is a socket */
1330 return BADSYN_CMD;
1331
1332 /* The variables $smtp_command and $smtp_command_argument point into the
1333 unmodified input buffer. A copy of the latter is taken for actual
1334 processing, so that it can be chopped up into separate parts if necessary,
1335 for example, when processing a MAIL command options such as SIZE that can
1336 follow the sender address. */
1337
1338 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1339 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1340 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1341 smtp_cmd_data = smtp_data_buffer;
1342
1343 /* Count non-mail commands from those hosts that are controlled in this
1344 way. The default is all hosts. We don't waste effort checking the list
1345 until we get a non-mail command, but then cache the result to save checking
1346 again. If there's a DEFER while checking the host, assume it's in the list.
1347
1348 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1349 start of each incoming message by fiddling with the value in the table. */
1350
1351 if (!p->is_mail_cmd)
1352 {
1353 if (count_nonmail == TRUE_UNSET) count_nonmail =
1354 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1355 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1356 return TOO_MANY_NONMAIL_CMD;
1357 }
1358
1359 /* If there is data for a command that does not expect it, generate the
1360 error here. */
1361
1362 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1363 }
1364 }
1365
1366 #ifdef SUPPORT_PROXY
1367 /* Only allow QUIT command if Proxy Protocol parsing failed */
1368 if (proxy_session && proxy_session_failed)
1369 return PROXY_FAIL_IGNORE_CMD;
1370 #endif
1371
1372 /* Enforce synchronization for unknown commands */
1373
1374 if (smtp_inptr < smtp_inend && /* Outstanding input */
1375 check_sync && /* Local flag set */
1376 smtp_enforce_sync && /* Global flag set */
1377 sender_host_address != NULL && /* Not local input */
1378 !sender_host_notsocket) /* Really is a socket */
1379 return BADSYN_CMD;
1380
1381 return OTHER_CMD;
1382 }
1383
1384
1385
1386 /*************************************************
1387 * Forced closedown of call *
1388 *************************************************/
1389
1390 /* This function is called from log.c when Exim is dying because of a serious
1391 disaster, and also from some other places. If an incoming non-batched SMTP
1392 channel is open, it swallows the rest of the incoming message if in the DATA
1393 phase, sends the reply string, and gives an error to all subsequent commands
1394 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1395 smtp_in.
1396
1397 Arguments:
1398 message SMTP reply string to send, excluding the code
1399
1400 Returns: nothing
1401 */
1402
1403 void
1404 smtp_closedown(uschar *message)
1405 {
1406 if (smtp_in == NULL || smtp_batched_input) return;
1407 receive_swallow_smtp();
1408 smtp_printf("421 %s\r\n", message);
1409
1410 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1411 {
1412 case EOF_CMD:
1413 return;
1414
1415 case QUIT_CMD:
1416 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1417 mac_smtp_fflush();
1418 return;
1419
1420 case RSET_CMD:
1421 smtp_printf("250 Reset OK\r\n");
1422 break;
1423
1424 default:
1425 smtp_printf("421 %s\r\n", message);
1426 break;
1427 }
1428 }
1429
1430
1431
1432
1433 /*************************************************
1434 * Set up connection info for logging *
1435 *************************************************/
1436
1437 /* This function is called when logging information about an SMTP connection.
1438 It sets up appropriate source information, depending on the type of connection.
1439 If sender_fullhost is NULL, we are at a very early stage of the connection;
1440 just use the IP address.
1441
1442 Argument: none
1443 Returns: a string describing the connection
1444 */
1445
1446 uschar *
1447 smtp_get_connection_info(void)
1448 {
1449 const uschar * hostname = sender_fullhost
1450 ? sender_fullhost : sender_host_address;
1451
1452 if (host_checking)
1453 return string_sprintf("SMTP connection from %s", hostname);
1454
1455 if (sender_host_unknown || sender_host_notsocket)
1456 return string_sprintf("SMTP connection from %s", sender_ident);
1457
1458 if (is_inetd)
1459 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1460
1461 if (LOGGING(incoming_interface) && interface_address != NULL)
1462 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1463 interface_address, interface_port);
1464
1465 return string_sprintf("SMTP connection from %s", hostname);
1466 }
1467
1468
1469
1470 #ifdef SUPPORT_TLS
1471 /* Append TLS-related information to a log line
1472
1473 Arguments:
1474 s String under construction: allocated string to extend, or NULL
1475 sizep Pointer to current allocation size (update on return), or NULL
1476 ptrp Pointer to index for new entries in string (update on return), or NULL
1477
1478 Returns: Allocated string or NULL
1479 */
1480 static uschar *
1481 s_tlslog(uschar * s, int * sizep, int * ptrp)
1482 {
1483 int size = sizep ? *sizep : 0;
1484 int ptr = ptrp ? *ptrp : 0;
1485
1486 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1487 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1488 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1489 s = string_append(s, &size, &ptr, 2, US" CV=",
1490 tls_in.certificate_verified? "yes":"no");
1491 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1492 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1493 string_printing(tls_in.peerdn), US"\"");
1494 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1495 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1496 string_printing(tls_in.sni), US"\"");
1497
1498 if (s)
1499 {
1500 s[ptr] = '\0';
1501 if (sizep) *sizep = size;
1502 if (ptrp) *ptrp = ptr;
1503 }
1504 return s;
1505 }
1506 #endif
1507
1508 /*************************************************
1509 * Log lack of MAIL if so configured *
1510 *************************************************/
1511
1512 /* This function is called when an SMTP session ends. If the log selector
1513 smtp_no_mail is set, write a log line giving some details of what has happened
1514 in the SMTP session.
1515
1516 Arguments: none
1517 Returns: nothing
1518 */
1519
1520 void
1521 smtp_log_no_mail(void)
1522 {
1523 int size, ptr, i;
1524 uschar *s, *sep;
1525
1526 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1527 return;
1528
1529 s = NULL;
1530 size = ptr = 0;
1531
1532 if (sender_host_authenticated != NULL)
1533 {
1534 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1535 if (authenticated_id != NULL)
1536 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1537 }
1538
1539 #ifdef SUPPORT_TLS
1540 s = s_tlslog(s, &size, &ptr);
1541 #endif
1542
1543 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1544 US" C=..." : US" C=";
1545 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1546 {
1547 if (smtp_connection_had[i] != SCH_NONE)
1548 {
1549 s = string_append(s, &size, &ptr, 2, sep,
1550 smtp_names[smtp_connection_had[i]]);
1551 sep = US",";
1552 }
1553 }
1554
1555 for (i = 0; i < smtp_ch_index; i++)
1556 {
1557 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1558 sep = US",";
1559 }
1560
1561 if (s != NULL) s[ptr] = 0; else s = US"";
1562 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1563 host_and_ident(FALSE),
1564 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1565 s);
1566 }
1567
1568
1569
1570 /*************************************************
1571 * Check HELO line and set sender_helo_name *
1572 *************************************************/
1573
1574 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1575 the domain name of the sending host, or an ip literal in square brackets. The
1576 argument is placed in sender_helo_name, which is in malloc store, because it
1577 must persist over multiple incoming messages. If helo_accept_junk is set, this
1578 host is permitted to send any old junk (needed for some broken hosts).
1579 Otherwise, helo_allow_chars can be used for rogue characters in general
1580 (typically people want to let in underscores).
1581
1582 Argument:
1583 s the data portion of the line (already past any white space)
1584
1585 Returns: TRUE or FALSE
1586 */
1587
1588 static BOOL
1589 check_helo(uschar *s)
1590 {
1591 uschar *start = s;
1592 uschar *end = s + Ustrlen(s);
1593 BOOL yield = helo_accept_junk;
1594
1595 /* Discard any previous helo name */
1596
1597 if (sender_helo_name != NULL)
1598 {
1599 store_free(sender_helo_name);
1600 sender_helo_name = NULL;
1601 }
1602
1603 /* Skip tests if junk is permitted. */
1604
1605 if (!yield)
1606 {
1607 /* Allow the new standard form for IPv6 address literals, namely,
1608 [IPv6:....], and because someone is bound to use it, allow an equivalent
1609 IPv4 form. Allow plain addresses as well. */
1610
1611 if (*s == '[')
1612 {
1613 if (end[-1] == ']')
1614 {
1615 end[-1] = 0;
1616 if (strncmpic(s, US"[IPv6:", 6) == 0)
1617 yield = (string_is_ip_address(s+6, NULL) == 6);
1618 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1619 yield = (string_is_ip_address(s+6, NULL) == 4);
1620 else
1621 yield = (string_is_ip_address(s+1, NULL) != 0);
1622 end[-1] = ']';
1623 }
1624 }
1625
1626 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1627 that have been configured (usually underscore - sigh). */
1628
1629 else if (*s != 0)
1630 {
1631 yield = TRUE;
1632 while (*s != 0)
1633 {
1634 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1635 Ustrchr(helo_allow_chars, *s) == NULL)
1636 {
1637 yield = FALSE;
1638 break;
1639 }
1640 s++;
1641 }
1642 }
1643 }
1644
1645 /* Save argument if OK */
1646
1647 if (yield) sender_helo_name = string_copy_malloc(start);
1648 return yield;
1649 }
1650
1651
1652
1653
1654
1655 /*************************************************
1656 * Extract SMTP command option *
1657 *************************************************/
1658
1659 /* This function picks the next option setting off the end of smtp_cmd_data. It
1660 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1661 things that can appear there.
1662
1663 Arguments:
1664 name point this at the name
1665 value point this at the data string
1666
1667 Returns: TRUE if found an option
1668 */
1669
1670 static BOOL
1671 extract_option(uschar **name, uschar **value)
1672 {
1673 uschar *n;
1674 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1675 while (isspace(*v)) v--;
1676 v[1] = 0;
1677 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1678
1679 n = v;
1680 if (*v == '=')
1681 {
1682 while(isalpha(n[-1])) n--;
1683 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1684 if (!isspace(n[-1])) return FALSE;
1685 n[-1] = 0;
1686 }
1687 else
1688 {
1689 n++;
1690 if (v == smtp_cmd_data) return FALSE;
1691 }
1692 *v++ = 0;
1693 *name = n;
1694 *value = v;
1695 return TRUE;
1696 }
1697
1698
1699
1700
1701
1702 /*************************************************
1703 * Reset for new message *
1704 *************************************************/
1705
1706 /* This function is called whenever the SMTP session is reset from
1707 within either of the setup functions.
1708
1709 Argument: the stacking pool storage reset point
1710 Returns: nothing
1711 */
1712
1713 static void
1714 smtp_reset(void *reset_point)
1715 {
1716 store_reset(reset_point);
1717 recipients_list = NULL;
1718 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1719 raw_recipients_count = recipients_count = recipients_list_max = 0;
1720 cancel_cutthrough_connection("smtp reset");
1721 message_linecount = 0;
1722 message_size = -1;
1723 acl_added_headers = NULL;
1724 acl_removed_headers = NULL;
1725 queue_only_policy = FALSE;
1726 rcpt_smtp_response = NULL;
1727 rcpt_smtp_response_same = TRUE;
1728 rcpt_in_progress = FALSE;
1729 deliver_freeze = FALSE; /* Can be set by ACL */
1730 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1731 fake_response = OK; /* Can be set by ACL */
1732 #ifdef WITH_CONTENT_SCAN
1733 no_mbox_unspool = FALSE; /* Can be set by ACL */
1734 #endif
1735 submission_mode = FALSE; /* Can be set by ACL */
1736 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1737 active_local_from_check = local_from_check; /* Can be set by ACL */
1738 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1739 sender_address = NULL;
1740 submission_name = NULL; /* Can be set by ACL */
1741 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1742 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1743 sender_verified_list = NULL; /* No senders verified */
1744 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1745 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1746
1747 authenticated_sender = NULL;
1748 #ifdef EXPERIMENTAL_BRIGHTMAIL
1749 bmi_run = 0;
1750 bmi_verdicts = NULL;
1751 #endif
1752 #ifndef DISABLE_DKIM
1753 dkim_signers = NULL;
1754 dkim_disable_verify = FALSE;
1755 dkim_collect_input = FALSE;
1756 #endif
1757 dsn_ret = 0;
1758 dsn_envid = NULL;
1759 #ifndef DISABLE_PRDR
1760 prdr_requested = FALSE;
1761 #endif
1762 #ifdef EXPERIMENTAL_SPF
1763 spf_header_comment = NULL;
1764 spf_received = NULL;
1765 spf_result = NULL;
1766 spf_smtp_comment = NULL;
1767 #endif
1768 #ifdef SUPPORT_I18N
1769 message_smtputf8 = FALSE;
1770 #endif
1771 body_linecount = body_zerocount = 0;
1772
1773 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1774 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1775 /* Note that ratelimiters_conn persists across resets. */
1776
1777 /* Reset message ACL variables */
1778
1779 acl_var_m = NULL;
1780
1781 /* The message body variables use malloc store. They may be set if this is
1782 not the first message in an SMTP session and the previous message caused them
1783 to be referenced in an ACL. */
1784
1785 if (message_body != NULL)
1786 {
1787 store_free(message_body);
1788 message_body = NULL;
1789 }
1790
1791 if (message_body_end != NULL)
1792 {
1793 store_free(message_body_end);
1794 message_body_end = NULL;
1795 }
1796
1797 /* Warning log messages are also saved in malloc store. They are saved to avoid
1798 repetition in the same message, but it seems right to repeat them for different
1799 messages. */
1800
1801 while (acl_warn_logged != NULL)
1802 {
1803 string_item *this = acl_warn_logged;
1804 acl_warn_logged = acl_warn_logged->next;
1805 store_free(this);
1806 }
1807 }
1808
1809
1810
1811
1812
1813 /*************************************************
1814 * Initialize for incoming batched SMTP message *
1815 *************************************************/
1816
1817 /* This function is called from smtp_setup_msg() in the case when
1818 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1819 of messages in one file with SMTP commands between them. All errors must be
1820 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1821 relevant. After an error on a sender, or an invalid recipient, the remainder
1822 of the message is skipped. The value of received_protocol is already set.
1823
1824 Argument: none
1825 Returns: > 0 message successfully started (reached DATA)
1826 = 0 QUIT read or end of file reached
1827 < 0 should not occur
1828 */
1829
1830 static int
1831 smtp_setup_batch_msg(void)
1832 {
1833 int done = 0;
1834 void *reset_point = store_get(0);
1835
1836 /* Save the line count at the start of each transaction - single commands
1837 like HELO and RSET count as whole transactions. */
1838
1839 bsmtp_transaction_linecount = receive_linecount;
1840
1841 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1842
1843 smtp_reset(reset_point); /* Reset for start of message */
1844
1845 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1846 value. The values are 2 larger than the required yield of the function. */
1847
1848 while (done <= 0)
1849 {
1850 uschar *errmess;
1851 uschar *recipient = NULL;
1852 int start, end, sender_domain, recipient_domain;
1853
1854 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1855 {
1856 /* The HELO/EHLO commands set sender_address_helo if they have
1857 valid data; otherwise they are ignored, except that they do
1858 a reset of the state. */
1859
1860 case HELO_CMD:
1861 case EHLO_CMD:
1862
1863 check_helo(smtp_cmd_data);
1864 /* Fall through */
1865
1866 case RSET_CMD:
1867 smtp_reset(reset_point);
1868 bsmtp_transaction_linecount = receive_linecount;
1869 break;
1870
1871
1872 /* The MAIL FROM command requires an address as an operand. All we
1873 do here is to parse it for syntactic correctness. The form "<>" is
1874 a special case which converts into an empty string. The start/end
1875 pointers in the original are not used further for this address, as
1876 it is the canonical extracted address which is all that is kept. */
1877
1878 case MAIL_CMD:
1879 smtp_mailcmd_count++; /* Count for no-mail log */
1880 if (sender_address != NULL)
1881 /* The function moan_smtp_batch() does not return. */
1882 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1883
1884 if (smtp_cmd_data[0] == 0)
1885 /* The function moan_smtp_batch() does not return. */
1886 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1887
1888 /* Reset to start of message */
1889
1890 smtp_reset(reset_point);
1891
1892 /* Apply SMTP rewrite */
1893
1894 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1895 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1896 US"", global_rewrite_rules) : smtp_cmd_data;
1897
1898 /* Extract the address; the TRUE flag allows <> as valid */
1899
1900 raw_sender =
1901 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1902 TRUE);
1903
1904 if (raw_sender == NULL)
1905 /* The function moan_smtp_batch() does not return. */
1906 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1907
1908 sender_address = string_copy(raw_sender);
1909
1910 /* Qualify unqualified sender addresses if permitted to do so. */
1911
1912 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1913 {
1914 if (allow_unqualified_sender)
1915 {
1916 sender_address = rewrite_address_qualify(sender_address, FALSE);
1917 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1918 "and rewritten\n", raw_sender);
1919 }
1920 /* The function moan_smtp_batch() does not return. */
1921 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1922 "a domain");
1923 }
1924 break;
1925
1926
1927 /* The RCPT TO command requires an address as an operand. All we do
1928 here is to parse it for syntactic correctness. There may be any number
1929 of RCPT TO commands, specifying multiple senders. We build them all into
1930 a data structure that is in argc/argv format. The start/end values
1931 given by parse_extract_address are not used, as we keep only the
1932 extracted address. */
1933
1934 case RCPT_CMD:
1935 if (sender_address == NULL)
1936 /* The function moan_smtp_batch() does not return. */
1937 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1938
1939 if (smtp_cmd_data[0] == 0)
1940 /* The function moan_smtp_batch() does not return. */
1941 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1942
1943 /* Check maximum number allowed */
1944
1945 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1946 /* The function moan_smtp_batch() does not return. */
1947 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1948 recipients_max_reject? "552": "452");
1949
1950 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1951 recipient address */
1952
1953 recipient = rewrite_existflags & rewrite_smtp
1954 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1955 global_rewrite_rules)
1956 : smtp_cmd_data;
1957
1958 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1959 &recipient_domain, FALSE);
1960
1961 if (!recipient)
1962 /* The function moan_smtp_batch() does not return. */
1963 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1964
1965 /* If the recipient address is unqualified, qualify it if permitted. Then
1966 add it to the list of recipients. */
1967
1968 if (recipient_domain == 0)
1969 {
1970 if (allow_unqualified_recipient)
1971 {
1972 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1973 recipient);
1974 recipient = rewrite_address_qualify(recipient, TRUE);
1975 }
1976 /* The function moan_smtp_batch() does not return. */
1977 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1978 "a domain");
1979 }
1980 receive_add_recipient(recipient, -1);
1981 break;
1982
1983
1984 /* The DATA command is legal only if it follows successful MAIL FROM
1985 and RCPT TO commands. This function is complete when a valid DATA
1986 command is encountered. */
1987
1988 case DATA_CMD:
1989 if (sender_address == NULL || recipients_count <= 0)
1990 {
1991 /* The function moan_smtp_batch() does not return. */
1992 if (sender_address == NULL)
1993 moan_smtp_batch(smtp_cmd_buffer,
1994 "503 MAIL FROM:<sender> command must precede DATA");
1995 else
1996 moan_smtp_batch(smtp_cmd_buffer,
1997 "503 RCPT TO:<recipient> must precede DATA");
1998 }
1999 else
2000 {
2001 done = 3; /* DATA successfully achieved */
2002 message_ended = END_NOTENDED; /* Indicate in middle of message */
2003 }
2004 break;
2005
2006
2007 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2008
2009 case VRFY_CMD:
2010 case EXPN_CMD:
2011 case HELP_CMD:
2012 case NOOP_CMD:
2013 case ETRN_CMD:
2014 bsmtp_transaction_linecount = receive_linecount;
2015 break;
2016
2017
2018 case EOF_CMD:
2019 case QUIT_CMD:
2020 done = 2;
2021 break;
2022
2023
2024 case BADARG_CMD:
2025 /* The function moan_smtp_batch() does not return. */
2026 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2027 break;
2028
2029
2030 case BADCHAR_CMD:
2031 /* The function moan_smtp_batch() does not return. */
2032 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2033 break;
2034
2035
2036 default:
2037 /* The function moan_smtp_batch() does not return. */
2038 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2039 break;
2040 }
2041 }
2042
2043 return done - 2; /* Convert yield values */
2044 }
2045
2046
2047
2048
2049 /*************************************************
2050 * Start an SMTP session *
2051 *************************************************/
2052
2053 /* This function is called at the start of an SMTP session. Thereafter,
2054 smtp_setup_msg() is called to initiate each separate message. This
2055 function does host-specific testing, and outputs the banner line.
2056
2057 Arguments: none
2058 Returns: FALSE if the session can not continue; something has
2059 gone wrong, or the connection to the host is blocked
2060 */
2061
2062 BOOL
2063 smtp_start_session(void)
2064 {
2065 int size = 256;
2066 int ptr, esclen;
2067 uschar *user_msg, *log_msg;
2068 uschar *code, *esc;
2069 uschar *p, *s, *ss;
2070
2071 smtp_connection_start = time(NULL);
2072 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2073 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2074 smtp_ch_index = 0;
2075
2076 /* Default values for certain variables */
2077
2078 helo_seen = esmtp = helo_accept_junk = FALSE;
2079 smtp_mailcmd_count = 0;
2080 count_nonmail = TRUE_UNSET;
2081 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2082 smtp_delay_mail = smtp_rlm_base;
2083 auth_advertised = FALSE;
2084 pipelining_advertised = FALSE;
2085 pipelining_enable = TRUE;
2086 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2087 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2088
2089 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2090 authentication settings from -oMaa to remain in force. */
2091
2092 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2093 authenticated_by = NULL;
2094
2095 #ifdef SUPPORT_TLS
2096 tls_in.cipher = tls_in.peerdn = NULL;
2097 tls_in.ourcert = tls_in.peercert = NULL;
2098 tls_in.sni = NULL;
2099 tls_in.ocsp = OCSP_NOT_REQ;
2100 tls_advertised = FALSE;
2101 #endif
2102 dsn_advertised = FALSE;
2103 #ifdef SUPPORT_I18N
2104 smtputf8_advertised = FALSE;
2105 #endif
2106
2107 /* Reset ACL connection variables */
2108
2109 acl_var_c = NULL;
2110
2111 /* Allow for trailing 0 in the command and data buffers. */
2112
2113 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2114 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2115 "malloc() failed for SMTP command buffer");
2116
2117 smtp_cmd_buffer[0] = 0;
2118 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2119
2120 /* For batched input, the protocol setting can be overridden from the
2121 command line by a trusted caller. */
2122
2123 if (smtp_batched_input)
2124 {
2125 if (!received_protocol) received_protocol = US"local-bsmtp";
2126 }
2127
2128 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2129 reset later if any of EHLO/AUTH/STARTTLS are received. */
2130
2131 else
2132 received_protocol =
2133 (sender_host_address ? protocols : protocols_local) [pnormal];
2134
2135 /* Set up the buffer for inputting using direct read() calls, and arrange to
2136 call the local functions instead of the standard C ones. */
2137
2138 if (!(smtp_inbuffer = (uschar *)malloc(IN_BUFFER_SIZE)))
2139 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2140
2141 receive_getc = smtp_getc;
2142 receive_get_cache = smtp_get_cache;
2143 receive_ungetc = smtp_ungetc;
2144 receive_feof = smtp_feof;
2145 receive_ferror = smtp_ferror;
2146 receive_smtp_buffered = smtp_buffered;
2147 smtp_inptr = smtp_inend = smtp_inbuffer;
2148 smtp_had_eof = smtp_had_error = 0;
2149
2150 /* Set up the message size limit; this may be host-specific */
2151
2152 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2153 if (expand_string_message != NULL)
2154 {
2155 if (thismessage_size_limit == -1)
2156 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2157 "%s", expand_string_message);
2158 else
2159 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2160 "%s", expand_string_message);
2161 smtp_closedown(US"Temporary local problem - please try later");
2162 return FALSE;
2163 }
2164
2165 /* When a message is input locally via the -bs or -bS options, sender_host_
2166 unknown is set unless -oMa was used to force an IP address, in which case it
2167 is checked like a real remote connection. When -bs is used from inetd, this
2168 flag is not set, causing the sending host to be checked. The code that deals
2169 with IP source routing (if configured) is never required for -bs or -bS and
2170 the flag sender_host_notsocket is used to suppress it.
2171
2172 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2173 reserve for certain hosts and/or networks. */
2174
2175 if (!sender_host_unknown)
2176 {
2177 int rc;
2178 BOOL reserved_host = FALSE;
2179
2180 /* Look up IP options (source routing info) on the socket if this is not an
2181 -oMa "host", and if any are found, log them and drop the connection.
2182
2183 Linux (and others now, see below) is different to everyone else, so there
2184 has to be some conditional compilation here. Versions of Linux before 2.1.15
2185 used a structure whose name was "options". Somebody finally realized that
2186 this name was silly, and it got changed to "ip_options". I use the
2187 newer name here, but there is a fudge in the script that sets up os.h
2188 to define a macro in older Linux systems.
2189
2190 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2191 glibc 2, which has chosen ip_opts for the structure name. This is now
2192 really a glibc thing rather than a Linux thing, so the condition name
2193 has been changed to reflect this. It is relevant also to GNU/Hurd.
2194
2195 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2196 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2197 a special macro defined in the os.h file.
2198
2199 Some DGUX versions on older hardware appear not to support IP options at
2200 all, so there is now a general macro which can be set to cut out this
2201 support altogether.
2202
2203 How to do this properly in IPv6 is not yet known. */
2204
2205 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2206
2207 #ifdef GLIBC_IP_OPTIONS
2208 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2209 #define OPTSTYLE 1
2210 #else
2211 #define OPTSTYLE 2
2212 #endif
2213 #elif defined DARWIN_IP_OPTIONS
2214 #define OPTSTYLE 2
2215 #else
2216 #define OPTSTYLE 3
2217 #endif
2218
2219 if (!host_checking && !sender_host_notsocket)
2220 {
2221 #if OPTSTYLE == 1
2222 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2223 struct ip_options *ipopt = store_get(optlen);
2224 #elif OPTSTYLE == 2
2225 struct ip_opts ipoptblock;
2226 struct ip_opts *ipopt = &ipoptblock;
2227 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2228 #else
2229 struct ipoption ipoptblock;
2230 struct ipoption *ipopt = &ipoptblock;
2231 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2232 #endif
2233
2234 /* Occasional genuine failures of getsockopt() have been seen - for
2235 example, "reset by peer". Therefore, just log and give up on this
2236 call, unless the error is ENOPROTOOPT. This error is given by systems
2237 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2238 of writing. So for that error, carry on - we just can't do an IP options
2239 check. */
2240
2241 DEBUG(D_receive) debug_printf("checking for IP options\n");
2242
2243 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2244 &optlen) < 0)
2245 {
2246 if (errno != ENOPROTOOPT)
2247 {
2248 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2249 host_and_ident(FALSE), strerror(errno));
2250 smtp_printf("451 SMTP service not available\r\n");
2251 return FALSE;
2252 }
2253 }
2254
2255 /* Deal with any IP options that are set. On the systems I have looked at,
2256 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2257 more logging data than will fit in big_buffer. Nevertheless, after somebody
2258 questioned this code, I've added in some paranoid checking. */
2259
2260 else if (optlen > 0)
2261 {
2262 uschar *p = big_buffer;
2263 uschar *pend = big_buffer + big_buffer_size;
2264 uschar *opt, *adptr;
2265 int optcount;
2266 struct in_addr addr;
2267
2268 #if OPTSTYLE == 1
2269 uschar *optstart = (uschar *)(ipopt->__data);
2270 #elif OPTSTYLE == 2
2271 uschar *optstart = (uschar *)(ipopt->ip_opts);
2272 #else
2273 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2274 #endif
2275
2276 DEBUG(D_receive) debug_printf("IP options exist\n");
2277
2278 Ustrcpy(p, "IP options on incoming call:");
2279 p += Ustrlen(p);
2280
2281 for (opt = optstart; opt != NULL &&
2282 opt < (uschar *)(ipopt) + optlen;)
2283 {
2284 switch (*opt)
2285 {
2286 case IPOPT_EOL:
2287 opt = NULL;
2288 break;
2289
2290 case IPOPT_NOP:
2291 opt++;
2292 break;
2293
2294 case IPOPT_SSRR:
2295 case IPOPT_LSRR:
2296 if (!string_format(p, pend-p, " %s [@%s",
2297 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2298 #if OPTSTYLE == 1
2299 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2300 #elif OPTSTYLE == 2
2301 inet_ntoa(ipopt->ip_dst)))
2302 #else
2303 inet_ntoa(ipopt->ipopt_dst)))
2304 #endif
2305 {
2306 opt = NULL;
2307 break;
2308 }
2309
2310 p += Ustrlen(p);
2311 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2312 adptr = opt + 3;
2313 while (optcount-- > 0)
2314 {
2315 memcpy(&addr, adptr, sizeof(addr));
2316 if (!string_format(p, pend - p - 1, "%s%s",
2317 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2318 {
2319 opt = NULL;
2320 break;
2321 }
2322 p += Ustrlen(p);
2323 adptr += sizeof(struct in_addr);
2324 }
2325 *p++ = ']';
2326 opt += opt[1];
2327 break;
2328
2329 default:
2330 {
2331 int i;
2332 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2333 Ustrcat(p, "[ ");
2334 p += 2;
2335 for (i = 0; i < opt[1]; i++)
2336 {
2337 sprintf(CS p, "%2.2x ", opt[i]);
2338 p += 3;
2339 }
2340 *p++ = ']';
2341 }
2342 opt += opt[1];
2343 break;
2344 }
2345 }
2346
2347 *p = 0;
2348 log_write(0, LOG_MAIN, "%s", big_buffer);
2349
2350 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2351
2352 log_write(0, LOG_MAIN|LOG_REJECT,
2353 "connection from %s refused (IP options)", host_and_ident(FALSE));
2354
2355 smtp_printf("554 SMTP service not available\r\n");
2356 return FALSE;
2357 }
2358
2359 /* Length of options = 0 => there are no options */
2360
2361 else DEBUG(D_receive) debug_printf("no IP options found\n");
2362 }
2363 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2364
2365 /* Set keep-alive in socket options. The option is on by default. This
2366 setting is an attempt to get rid of some hanging connections that stick in
2367 read() when the remote end (usually a dialup) goes away. */
2368
2369 if (smtp_accept_keepalive && !sender_host_notsocket)
2370 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2371
2372 /* If the current host matches host_lookup, set the name by doing a
2373 reverse lookup. On failure, sender_host_name will be NULL and
2374 host_lookup_failed will be TRUE. This may or may not be serious - optional
2375 checks later. */
2376
2377 if (verify_check_host(&host_lookup) == OK)
2378 {
2379 (void)host_name_lookup();
2380 host_build_sender_fullhost();
2381 }
2382
2383 /* Delay this until we have the full name, if it is looked up. */
2384
2385 set_process_info("handling incoming connection from %s",
2386 host_and_ident(FALSE));
2387
2388 /* Expand smtp_receive_timeout, if needed */
2389
2390 if (smtp_receive_timeout_s)
2391 {
2392 uschar * exp;
2393 if ( !(exp = expand_string(smtp_receive_timeout_s))
2394 || !(*exp)
2395 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2396 )
2397 log_write(0, LOG_MAIN|LOG_PANIC,
2398 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2399 }
2400
2401 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2402 smtps port for use with older style SSL MTAs. */
2403
2404 #ifdef SUPPORT_TLS
2405 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2406 return FALSE;
2407 #endif
2408
2409 /* Test for explicit connection rejection */
2410
2411 if (verify_check_host(&host_reject_connection) == OK)
2412 {
2413 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2414 "from %s (host_reject_connection)", host_and_ident(FALSE));
2415 smtp_printf("554 SMTP service not available\r\n");
2416 return FALSE;
2417 }
2418
2419 /* Test with TCP Wrappers if so configured. There is a problem in that
2420 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2421 such as disks dying. In these cases, it is desirable to reject with a 4xx
2422 error instead of a 5xx error. There isn't a "right" way to detect such
2423 problems. The following kludge is used: errno is zeroed before calling
2424 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2425 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2426 not exist). */
2427
2428 #ifdef USE_TCP_WRAPPERS
2429 errno = 0;
2430 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2431 if (tcp_wrappers_name == NULL)
2432 {
2433 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2434 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2435 expand_string_message);
2436 }
2437 if (!hosts_ctl(tcp_wrappers_name,
2438 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2439 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2440 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2441 {
2442 if (errno == 0 || errno == ENOENT)
2443 {
2444 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2445 log_write(L_connection_reject,
2446 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2447 "(tcp wrappers)", host_and_ident(FALSE));
2448 smtp_printf("554 SMTP service not available\r\n");
2449 }
2450 else
2451 {
2452 int save_errno = errno;
2453 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2454 "errno value %d\n", save_errno);
2455 log_write(L_connection_reject,
2456 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2457 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2458 smtp_printf("451 Temporary local problem - please try later\r\n");
2459 }
2460 return FALSE;
2461 }
2462 #endif
2463
2464 /* Check for reserved slots. The value of smtp_accept_count has already been
2465 incremented to include this process. */
2466
2467 if (smtp_accept_max > 0 &&
2468 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2469 {
2470 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2471 {
2472 log_write(L_connection_reject,
2473 LOG_MAIN, "temporarily refused connection from %s: not in "
2474 "reserve list: connected=%d max=%d reserve=%d%s",
2475 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2476 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2477 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2478 "please try again later\r\n", smtp_active_hostname);
2479 return FALSE;
2480 }
2481 reserved_host = TRUE;
2482 }
2483
2484 /* If a load level above which only messages from reserved hosts are
2485 accepted is set, check the load. For incoming calls via the daemon, the
2486 check is done in the superior process if there are no reserved hosts, to
2487 save a fork. In all cases, the load average will already be available
2488 in a global variable at this point. */
2489
2490 if (smtp_load_reserve >= 0 &&
2491 load_average > smtp_load_reserve &&
2492 !reserved_host &&
2493 verify_check_host(&smtp_reserve_hosts) != OK)
2494 {
2495 log_write(L_connection_reject,
2496 LOG_MAIN, "temporarily refused connection from %s: not in "
2497 "reserve list and load average = %.2f", host_and_ident(FALSE),
2498 (double)load_average/1000.0);
2499 smtp_printf("421 %s: Too much load; please try again later\r\n",
2500 smtp_active_hostname);
2501 return FALSE;
2502 }
2503
2504 /* Determine whether unqualified senders or recipients are permitted
2505 for this host. Unfortunately, we have to do this every time, in order to
2506 set the flags so that they can be inspected when considering qualifying
2507 addresses in the headers. For a site that permits no qualification, this
2508 won't take long, however. */
2509
2510 allow_unqualified_sender =
2511 verify_check_host(&sender_unqualified_hosts) == OK;
2512
2513 allow_unqualified_recipient =
2514 verify_check_host(&recipient_unqualified_hosts) == OK;
2515
2516 /* Determine whether HELO/EHLO is required for this host. The requirement
2517 can be hard or soft. */
2518
2519 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2520 if (!helo_required)
2521 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2522
2523 /* Determine whether this hosts is permitted to send syntactic junk
2524 after a HELO or EHLO command. */
2525
2526 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2527 }
2528
2529 /* For batch SMTP input we are now done. */
2530
2531 if (smtp_batched_input) return TRUE;
2532
2533 #ifdef SUPPORT_PROXY
2534 /* If valid Proxy Protocol source is connecting, set up session.
2535 * Failure will not allow any SMTP function other than QUIT. */
2536 proxy_session = FALSE;
2537 proxy_session_failed = FALSE;
2538 if (check_proxy_protocol_host())
2539 if (!setup_proxy_protocol_host())
2540 {
2541 proxy_session_failed = TRUE;
2542 DEBUG(D_receive)
2543 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2544 }
2545 else
2546 {
2547 sender_host_name = NULL;
2548 (void)host_name_lookup();
2549 host_build_sender_fullhost();
2550 }
2551 #endif
2552
2553 /* Run the ACL if it exists */
2554
2555 user_msg = NULL;
2556 if (acl_smtp_connect)
2557 {
2558 int rc;
2559 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2560 &log_msg)) != OK)
2561 {
2562 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2563 return FALSE;
2564 }
2565 }
2566
2567 /* Output the initial message for a two-way SMTP connection. It may contain
2568 newlines, which then cause a multi-line response to be given. */
2569
2570 code = US"220"; /* Default status code */
2571 esc = US""; /* Default extended status code */
2572 esclen = 0; /* Length of esc */
2573
2574 if (!user_msg)
2575 {
2576 if (!(s = expand_string(smtp_banner)))
2577 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2578 "failed: %s", smtp_banner, expand_string_message);
2579 }
2580 else
2581 {
2582 int codelen = 3;
2583 s = user_msg;
2584 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2585 if (codelen > 4)
2586 {
2587 esc = code + 4;
2588 esclen = codelen - 4;
2589 }
2590 }
2591
2592 /* Remove any terminating newlines; might as well remove trailing space too */
2593
2594 p = s + Ustrlen(s);
2595 while (p > s && isspace(p[-1])) p--;
2596 *p = 0;
2597
2598 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2599 is all contained in a single IP packet. The original code wrote out the
2600 greeting using several calls to fprint/fputc, and on busy servers this could
2601 cause it to be split over more than one packet - which caused CC:Mail to fall
2602 over when it got the second part of the greeting after sending its first
2603 command. Sigh. To try to avoid this, build the complete greeting message
2604 first, and output it in one fell swoop. This gives a better chance of it
2605 ending up as a single packet. */
2606
2607 ss = store_get(size);
2608 ptr = 0;
2609
2610 p = s;
2611 do /* At least once, in case we have an empty string */
2612 {
2613 int len;
2614 uschar *linebreak = Ustrchr(p, '\n');
2615 ss = string_catn(ss, &size, &ptr, code, 3);
2616 if (linebreak == NULL)
2617 {
2618 len = Ustrlen(p);
2619 ss = string_catn(ss, &size, &ptr, US" ", 1);
2620 }
2621 else
2622 {
2623 len = linebreak - p;
2624 ss = string_catn(ss, &size, &ptr, US"-", 1);
2625 }
2626 ss = string_catn(ss, &size, &ptr, esc, esclen);
2627 ss = string_catn(ss, &size, &ptr, p, len);
2628 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2629 p += len;
2630 if (linebreak != NULL) p++;
2631 }
2632 while (*p != 0);
2633
2634 ss[ptr] = 0; /* string_cat leaves room for this */
2635
2636 /* Before we write the banner, check that there is no input pending, unless
2637 this synchronisation check is disabled. */
2638
2639 if (!check_sync())
2640 {
2641 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2642 "synchronization error (input sent without waiting for greeting): "
2643 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2644 string_printing(smtp_inptr));
2645 smtp_printf("554 SMTP synchronization error\r\n");
2646 return FALSE;
2647 }
2648
2649 /* Now output the banner */
2650
2651 smtp_printf("%s", ss);
2652 return TRUE;
2653 }
2654
2655
2656
2657
2658
2659 /*************************************************
2660 * Handle SMTP syntax and protocol errors *
2661 *************************************************/
2662
2663 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2664 to do so. Then transmit the error response. The return value depends on the
2665 number of syntax and protocol errors in this SMTP session.
2666
2667 Arguments:
2668 type error type, given as a log flag bit
2669 code response code; <= 0 means don't send a response
2670 data data to reflect in the response (can be NULL)
2671 errmess the error message
2672
2673 Returns: -1 limit of syntax/protocol errors NOT exceeded
2674 +1 limit of syntax/protocol errors IS exceeded
2675
2676 These values fit in with the values of the "done" variable in the main
2677 processing loop in smtp_setup_msg(). */
2678
2679 static int
2680 synprot_error(int type, int code, uschar *data, uschar *errmess)
2681 {
2682 int yield = -1;
2683
2684 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2685 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2686 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2687
2688 if (++synprot_error_count > smtp_max_synprot_errors)
2689 {
2690 yield = 1;
2691 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2692 "syntax or protocol errors (last command was \"%s\")",
2693 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2694 }
2695
2696 if (code > 0)
2697 {
2698 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2699 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2700 if (yield == 1)
2701 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2702 }
2703
2704 return yield;
2705 }
2706
2707
2708
2709
2710 /*************************************************
2711 * Send SMTP response, possibly multiline *
2712 *************************************************/
2713
2714 /* There are, it seems, broken clients out there that cannot handle multiline
2715 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2716 output nothing for non-final calls, and only the first line for anything else.
2717
2718 Arguments:
2719 code SMTP code, may involve extended status codes
2720 codelen length of smtp code; if > 4 there's an ESC
2721 final FALSE if the last line isn't the final line
2722 msg message text, possibly containing newlines
2723
2724 Returns: nothing
2725 */
2726
2727 void
2728 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2729 {
2730 int esclen = 0;
2731 uschar *esc = US"";
2732
2733 if (!final && no_multiline_responses) return;
2734
2735 if (codelen > 4)
2736 {
2737 esc = code + 4;
2738 esclen = codelen - 4;
2739 }
2740
2741 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2742 have had the same. Note: this code is also present in smtp_printf(). It would
2743 be tidier to have it only in one place, but when it was added, it was easier to
2744 do it that way, so as not to have to mess with the code for the RCPT command,
2745 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2746
2747 if (rcpt_in_progress)
2748 {
2749 if (rcpt_smtp_response == NULL)
2750 rcpt_smtp_response = string_copy(msg);
2751 else if (rcpt_smtp_response_same &&
2752 Ustrcmp(rcpt_smtp_response, msg) != 0)
2753 rcpt_smtp_response_same = FALSE;
2754 rcpt_in_progress = FALSE;
2755 }
2756
2757 /* Not output the message, splitting it up into multiple lines if necessary. */
2758
2759 for (;;)
2760 {
2761 uschar *nl = Ustrchr(msg, '\n');
2762 if (nl == NULL)
2763 {
2764 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2765 return;
2766 }
2767 else if (nl[1] == 0 || no_multiline_responses)
2768 {
2769 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2770 (int)(nl - msg), msg);
2771 return;
2772 }
2773 else
2774 {
2775 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2776 msg = nl + 1;
2777 while (isspace(*msg)) msg++;
2778 }
2779 }
2780 }
2781
2782
2783
2784
2785 /*************************************************
2786 * Parse user SMTP message *
2787 *************************************************/
2788
2789 /* This function allows for user messages overriding the response code details
2790 by providing a suitable response code string at the start of the message
2791 user_msg. Check the message for starting with a response code and optionally an
2792 extended status code. If found, check that the first digit is valid, and if so,
2793 change the code pointer and length to use the replacement. An invalid code
2794 causes a panic log; in this case, if the log messages is the same as the user
2795 message, we must also adjust the value of the log message to show the code that
2796 is actually going to be used (the original one).
2797
2798 This function is global because it is called from receive.c as well as within
2799 this module.
2800
2801 Note that the code length returned includes the terminating whitespace
2802 character, which is always included in the regex match.
2803
2804 Arguments:
2805 code SMTP code, may involve extended status codes
2806 codelen length of smtp code; if > 4 there's an ESC
2807 msg message text
2808 log_msg optional log message, to be adjusted with the new SMTP code
2809 check_valid if true, verify the response code
2810
2811 Returns: nothing
2812 */
2813
2814 void
2815 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2816 BOOL check_valid)
2817 {
2818 int n;
2819 int ovector[3];
2820
2821 if (!msg || !*msg) return;
2822
2823 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2824 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
2825
2826 if (check_valid && (*msg)[0] != (*code)[0])
2827 {
2828 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2829 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2830 if (log_msg != NULL && *log_msg == *msg)
2831 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2832 }
2833 else
2834 {
2835 *code = *msg;
2836 *codelen = ovector[1]; /* Includes final space */
2837 }
2838 *msg += ovector[1]; /* Chop the code off the message */
2839 return;
2840 }
2841
2842
2843
2844
2845 /*************************************************
2846 * Handle an ACL failure *
2847 *************************************************/
2848
2849 /* This function is called when acl_check() fails. As well as calls from within
2850 this module, it is called from receive.c for an ACL after DATA. It sorts out
2851 logging the incident, and sets up the error response. A message containing
2852 newlines is turned into a multiline SMTP response, but for logging, only the
2853 first line is used.
2854
2855 There's a table of default permanent failure response codes to use in
2856 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2857 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2858 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2859 state, because there are broken clients that try VRFY before RCPT. A 5xx
2860 response should be given only when the address is positively known to be
2861 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2862 no explicit code, but if there is one we let it know best.
2863 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2864
2865 From Exim 4.63, it is possible to override the response code details by
2866 providing a suitable response code string at the start of the message provided
2867 in user_msg. The code's first digit is checked for validity.
2868
2869 Arguments:
2870 where where the ACL was called from
2871 rc the failure code
2872 user_msg a message that can be included in an SMTP response
2873 log_msg a message for logging
2874
2875 Returns: 0 in most cases
2876 2 if the failure code was FAIL_DROP, in which case the
2877 SMTP connection should be dropped (this value fits with the
2878 "done" variable in smtp_setup_msg() below)
2879 */
2880
2881 int
2882 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2883 {
2884 BOOL drop = rc == FAIL_DROP;
2885 int codelen = 3;
2886 uschar *smtp_code;
2887 uschar *lognl;
2888 uschar *sender_info = US"";
2889 uschar *what =
2890 #ifdef WITH_CONTENT_SCAN
2891 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
2892 #endif
2893 where == ACL_WHERE_PREDATA ? US"DATA" :
2894 where == ACL_WHERE_DATA ? US"after DATA" :
2895 #ifndef DISABLE_PRDR
2896 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
2897 #endif
2898 smtp_cmd_data ?
2899 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
2900 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
2901
2902 if (drop) rc = FAIL;
2903
2904 /* Set the default SMTP code, and allow a user message to change it. */
2905
2906 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2907 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2908 where != ACL_WHERE_VRFY);
2909
2910 /* We used to have sender_address here; however, there was a bug that was not
2911 updating sender_address after a rewrite during a verify. When this bug was
2912 fixed, sender_address at this point became the rewritten address. I'm not sure
2913 this is what should be logged, so I've changed to logging the unrewritten
2914 address to retain backward compatibility. */
2915
2916 #ifndef WITH_CONTENT_SCAN
2917 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2918 #else
2919 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2920 #endif
2921 {
2922 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2923 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2924 sender_host_authenticated ? US" A=" : US"",
2925 sender_host_authenticated ? sender_host_authenticated : US"",
2926 sender_host_authenticated && authenticated_id ? US":" : US"",
2927 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2928 );
2929 }
2930
2931 /* If there's been a sender verification failure with a specific message, and
2932 we have not sent a response about it yet, do so now, as a preliminary line for
2933 failures, but not defers. However, always log it for defer, and log it for fail
2934 unless the sender_verify_fail log selector has been turned off. */
2935
2936 if (sender_verified_failed &&
2937 !testflag(sender_verified_failed, af_sverify_told))
2938 {
2939 BOOL save_rcpt_in_progress = rcpt_in_progress;
2940 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2941
2942 setflag(sender_verified_failed, af_sverify_told);
2943
2944 if (rc != FAIL || LOGGING(sender_verify_fail))
2945 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2946 host_and_ident(TRUE),
2947 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2948 sender_verified_failed->address,
2949 (sender_verified_failed->message == NULL)? US"" :
2950 string_sprintf(": %s", sender_verified_failed->message));
2951
2952 if (rc == FAIL && sender_verified_failed->user_message)
2953 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2954 testflag(sender_verified_failed, af_verify_pmfail)?
2955 "Postmaster verification failed while checking <%s>\n%s\n"
2956 "Several RFCs state that you are required to have a postmaster\n"
2957 "mailbox for each mail domain. This host does not accept mail\n"
2958 "from domains whose servers reject the postmaster address."
2959 :
2960 testflag(sender_verified_failed, af_verify_nsfail)?
2961 "Callback setup failed while verifying <%s>\n%s\n"
2962 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2963 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2964 "RFC requirements, and stops you from receiving standard bounce\n"
2965 "messages. This host does not accept mail from domains whose servers\n"
2966 "refuse bounces."
2967 :
2968 "Verification failed for <%s>\n%s",
2969 sender_verified_failed->address,
2970 sender_verified_failed->user_message));
2971
2972 rcpt_in_progress = save_rcpt_in_progress;
2973 }
2974
2975 /* Sort out text for logging */
2976
2977 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
2978 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
2979
2980 /* Send permanent failure response to the command, but the code used isn't
2981 always a 5xx one - see comments at the start of this function. If the original
2982 rc was FAIL_DROP we drop the connection and yield 2. */
2983
2984 if (rc == FAIL)
2985 smtp_respond(smtp_code, codelen, TRUE,
2986 user_msg ? user_msg : US"Administrative prohibition");
2987
2988 /* Send temporary failure response to the command. Don't give any details,
2989 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2990 verb, and for a header verify when smtp_return_error_details is set.
2991
2992 This conditional logic is all somewhat of a mess because of the odd
2993 interactions between temp_details and return_error_details. One day it should
2994 be re-implemented in a tidier fashion. */
2995
2996 else
2997 if (acl_temp_details && user_msg)
2998 {
2999 if ( smtp_return_error_details
3000 && sender_verified_failed
3001 && sender_verified_failed->message
3002 )
3003 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3004
3005 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3006 }
3007 else
3008 smtp_respond(smtp_code, codelen, TRUE,
3009 US"Temporary local problem - please try later");
3010
3011 /* Log the incident to the logs that are specified by log_reject_target
3012 (default main, reject). This can be empty to suppress logging of rejections. If
3013 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3014 is closing if required and return 2. */
3015
3016 if (log_reject_target != 0)
3017 {
3018 #ifdef SUPPORT_TLS
3019 uschar * tls = s_tlslog(NULL, NULL, NULL);
3020 if (!tls) tls = US"";
3021 #else
3022 uschar * tls = US"";
3023 #endif
3024 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3025 log_reject_target, "%s%s%s %s%srejected %s%s",
3026 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3027 host_and_ident(TRUE),
3028 tls,
3029 sender_info,
3030 rc == FAIL ? US"" : US"temporarily ",
3031 what, log_msg);
3032 }
3033
3034 if (!drop) return 0;
3035
3036 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3037 smtp_get_connection_info());
3038
3039 /* Run the not-quit ACL, but without any custom messages. This should not be a
3040 problem, because we get here only if some other ACL has issued "drop", and
3041 in that case, *its* custom messages will have been used above. */
3042
3043 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3044 return 2;
3045 }
3046
3047
3048
3049
3050 /*************************************************
3051 * Handle SMTP exit when QUIT is not given *
3052 *************************************************/
3053
3054 /* This function provides a logging/statistics hook for when an SMTP connection
3055 is dropped on the floor or the other end goes away. It's a global function
3056 because it's called from receive.c as well as this module. As well as running
3057 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3058 response, either with a custom message from the ACL, or using a default. There
3059 is one case, however, when no message is output - after "drop". In that case,
3060 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3061 passed to this function.
3062
3063 In case things go wrong while processing this function, causing an error that
3064 may re-enter this function, there is a recursion check.
3065
3066 Arguments:
3067 reason What $smtp_notquit_reason will be set to in the ACL;
3068 if NULL, the ACL is not run
3069 code The error code to return as part of the response
3070 defaultrespond The default message if there's no user_msg
3071
3072 Returns: Nothing
3073 */
3074
3075 void
3076 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3077 {
3078 int rc;
3079 uschar *user_msg = NULL;
3080 uschar *log_msg = NULL;
3081
3082 /* Check for recursive acll */
3083
3084 if (smtp_exit_function_called)
3085 {
3086 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3087 reason);
3088 return;
3089 }
3090 smtp_exit_function_called = TRUE;
3091
3092 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3093
3094 if (acl_smtp_notquit && reason)
3095 {
3096 smtp_notquit_reason = reason;
3097 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3098 &log_msg)) == ERROR)
3099 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3100 log_msg);
3101 }
3102
3103 /* Write an SMTP response if we are expected to give one. As the default
3104 responses are all internal, they should always fit in the buffer, but code a
3105 warning, just in case. Note that string_vformat() still leaves a complete
3106 string, even if it is incomplete. */
3107
3108 if (code && defaultrespond)
3109 {
3110 if (user_msg)
3111 smtp_respond(code, 3, TRUE, user_msg);
3112 else
3113 {
3114 uschar buffer[128];
3115 va_list ap;
3116 va_start(ap, defaultrespond);
3117 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3118 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3119 smtp_printf("%s %s\r\n", code, buffer);
3120 va_end(ap);
3121 }
3122 mac_smtp_fflush();
3123 }
3124 }
3125
3126
3127
3128
3129 /*************************************************
3130 * Verify HELO argument *
3131 *************************************************/
3132
3133 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3134 matched. It is also called from ACL processing if verify = helo is used and
3135 verification was not previously tried (i.e. helo_try_verify_hosts was not
3136 matched). The result of its processing is to set helo_verified and
3137 helo_verify_failed. These variables should both be FALSE for this function to
3138 be called.
3139
3140 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3141 for IPv6 ::ffff: literals.
3142
3143 Argument: none
3144 Returns: TRUE if testing was completed;
3145 FALSE on a temporary failure
3146 */
3147
3148 BOOL
3149 smtp_verify_helo(void)
3150 {
3151 BOOL yield = TRUE;
3152
3153 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3154 sender_helo_name);
3155
3156 if (sender_helo_name == NULL)
3157 {
3158 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3159 }
3160
3161 /* Deal with the case of -bs without an IP address */
3162
3163 else if (sender_host_address == NULL)
3164 {
3165 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3166 helo_verified = TRUE;
3167 }
3168
3169 /* Deal with the more common case when there is a sending IP address */
3170
3171 else if (sender_helo_name[0] == '[')
3172 {
3173 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3174 Ustrlen(sender_host_address)) == 0;
3175
3176 #if HAVE_IPV6
3177 if (!helo_verified)
3178 {
3179 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3180 helo_verified = Ustrncmp(sender_helo_name + 1,
3181 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3182 }
3183 #endif
3184
3185 HDEBUG(D_receive)
3186 { if (helo_verified) debug_printf("matched host address\n"); }
3187 }
3188
3189 /* Do a reverse lookup if one hasn't already given a positive or negative
3190 response. If that fails, or the name doesn't match, try checking with a forward
3191 lookup. */
3192
3193 else
3194 {
3195 if (sender_host_name == NULL && !host_lookup_failed)
3196 yield = host_name_lookup() != DEFER;
3197
3198 /* If a host name is known, check it and all its aliases. */
3199
3200 if (sender_host_name)
3201 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3202 {
3203 sender_helo_dnssec = sender_host_dnssec;
3204 HDEBUG(D_receive) debug_printf("matched host name\n");
3205 }
3206 else
3207 {
3208 uschar **aliases = sender_host_aliases;
3209 while (*aliases)
3210 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3211 {
3212 sender_helo_dnssec = sender_host_dnssec;
3213 break;
3214 }
3215
3216 HDEBUG(D_receive) if (helo_verified)
3217 debug_printf("matched alias %s\n", *(--aliases));
3218 }
3219
3220 /* Final attempt: try a forward lookup of the helo name */
3221
3222 if (!helo_verified)
3223 {
3224 int rc;
3225 host_item h;
3226 dnssec_domains d;
3227 host_item *hh;
3228
3229 h.name = sender_helo_name;
3230 h.address = NULL;
3231 h.mx = MX_NONE;
3232 h.next = NULL;
3233 d.request = US"*";
3234 d.require = US"";
3235
3236 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3237 sender_helo_name);
3238 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3239 NULL, NULL, NULL, &d, NULL, NULL);
3240 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3241 for (hh = &h; hh; hh = hh->next)
3242 if (Ustrcmp(hh->address, sender_host_address) == 0)
3243 {
3244 helo_verified = TRUE;
3245 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3246 HDEBUG(D_receive)
3247 {
3248 debug_printf("IP address for %s matches calling address\n"
3249 "Forward DNS security status: %sverified\n",
3250 sender_helo_name, sender_helo_dnssec ? "" : "un");
3251 }
3252 break;
3253 }
3254 }
3255 }
3256
3257 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3258 return yield;
3259 }
3260
3261
3262
3263
3264 /*************************************************
3265 * Send user response message *
3266 *************************************************/
3267
3268 /* This function is passed a default response code and a user message. It calls
3269 smtp_message_code() to check and possibly modify the response code, and then
3270 calls smtp_respond() to transmit the response. I put this into a function
3271 just to avoid a lot of repetition.
3272
3273 Arguments:
3274 code the response code
3275 user_msg the user message
3276
3277 Returns: nothing
3278 */
3279
3280 static void
3281 smtp_user_msg(uschar *code, uschar *user_msg)
3282 {
3283 int len = 3;
3284 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3285 smtp_respond(code, len, TRUE, user_msg);
3286 }
3287
3288
3289
3290 static int
3291 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3292 {
3293 const uschar *set_id = NULL;
3294 int rc, i;
3295
3296 /* Run the checking code, passing the remainder of the command line as
3297 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3298 it as the only set numerical variable. The authenticator may set $auth<n>
3299 and also set other numeric variables. The $auth<n> variables are preferred
3300 nowadays; the numerical variables remain for backwards compatibility.
3301
3302 Afterwards, have a go at expanding the set_id string, even if
3303 authentication failed - for bad passwords it can be useful to log the
3304 userid. On success, require set_id to expand and exist, and put it in
3305 authenticated_id. Save this in permanent store, as the working store gets
3306 reset at HELO, RSET, etc. */
3307
3308 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3309 expand_nmax = 0;
3310 expand_nlength[0] = 0; /* $0 contains nothing */
3311
3312 rc = (au->info->servercode)(au, smtp_cmd_data);
3313 if (au->set_id) set_id = expand_string(au->set_id);
3314 expand_nmax = -1; /* Reset numeric variables */
3315 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3316
3317 /* The value of authenticated_id is stored in the spool file and printed in
3318 log lines. It must not contain binary zeros or newline characters. In
3319 normal use, it never will, but when playing around or testing, this error
3320 can (did) happen. To guard against this, ensure that the id contains only
3321 printing characters. */
3322
3323 if (set_id) set_id = string_printing(set_id);
3324
3325 /* For the non-OK cases, set up additional logging data if set_id
3326 is not empty. */
3327
3328 if (rc != OK)
3329 set_id = set_id && *set_id
3330 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3331
3332 /* Switch on the result */
3333
3334 switch(rc)
3335 {
3336 case OK:
3337 if (!au->set_id || set_id) /* Complete success */
3338 {
3339 if (set_id) authenticated_id = string_copy_malloc(set_id);
3340 sender_host_authenticated = au->name;
3341 authentication_failed = FALSE;
3342 authenticated_fail_id = NULL; /* Impossible to already be set? */
3343
3344 received_protocol =
3345 (sender_host_address ? protocols : protocols_local)
3346 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3347 *s = *ss = US"235 Authentication succeeded";
3348 authenticated_by = au;
3349 break;
3350 }
3351
3352 /* Authentication succeeded, but we failed to expand the set_id string.
3353 Treat this as a temporary error. */
3354
3355 auth_defer_msg = expand_string_message;
3356 /* Fall through */
3357
3358 case DEFER:
3359 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3360 *s = string_sprintf("435 Unable to authenticate at present%s",
3361 auth_defer_user_msg);
3362 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3363 set_id, auth_defer_msg);
3364 break;
3365
3366 case BAD64:
3367 *s = *ss = US"501 Invalid base64 data";
3368 break;
3369
3370 case CANCELLED:
3371 *s = *ss = US"501 Authentication cancelled";
3372 break;
3373
3374 case UNEXPECTED:
3375 *s = *ss = US"553 Initial data not expected";
3376 break;
3377
3378 case FAIL:
3379 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3380 *s = US"535 Incorrect authentication data";
3381 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3382 break;
3383
3384 default:
3385 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3386 *s = US"435 Internal error";
3387 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3388 "check", set_id, rc);
3389 break;
3390 }
3391
3392 return rc;
3393 }
3394
3395
3396
3397
3398
3399 static int
3400 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3401 {
3402 int rd;
3403 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3404 {
3405 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3406 *recipient);
3407 rd = Ustrlen(recipient) + 1;
3408 *recipient = rewrite_address_qualify(*recipient, TRUE);
3409 return rd;
3410 }
3411 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3412 smtp_cmd_data);
3413 log_write(L_smtp_syntax_error,
3414 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3415 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3416 return 0;
3417 }
3418
3419
3420
3421
3422 static void
3423 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3424 {
3425 HAD(SCH_QUIT);
3426 incomplete_transaction_log(US"QUIT");
3427 if (acl_smtp_quit)
3428 {
3429 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3430 if (rc == ERROR)
3431 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3432 *log_msgp);
3433 }
3434 if (*user_msgp)
3435 smtp_respond(US"221", 3, TRUE, *user_msgp);
3436 else
3437 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3438
3439 #ifdef SUPPORT_TLS
3440 tls_close(TRUE, TRUE);
3441 #endif
3442
3443 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3444 smtp_get_connection_info());
3445 }
3446
3447
3448 static void
3449 smtp_rset_handler(void)
3450 {
3451 HAD(SCH_RSET);
3452 incomplete_transaction_log(US"RSET");
3453 smtp_printf("250 Reset OK\r\n");
3454 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3455 }
3456
3457
3458
3459 /*************************************************
3460 * Initialize for SMTP incoming message *
3461 *************************************************/
3462
3463 /* This function conducts the initial dialogue at the start of an incoming SMTP
3464 message, and builds a list of recipients. However, if the incoming message
3465 is part of a batch (-bS option) a separate function is called since it would
3466 be messy having tests splattered about all over this function. This function
3467 therefore handles the case where interaction is occurring. The input and output
3468 files are set up in smtp_in and smtp_out.
3469
3470 The global recipients_list is set to point to a vector of recipient_item
3471 blocks, whose number is given by recipients_count. This is extended by the
3472 receive_add_recipient() function. The global variable sender_address is set to
3473 the sender's address. The yield is +1 if a message has been successfully
3474 started, 0 if a QUIT command was encountered or the connection was refused from
3475 the particular host, or -1 if the connection was lost.
3476
3477 Argument: none
3478
3479 Returns: > 0 message successfully started (reached DATA)
3480 = 0 QUIT read or end of file reached or call refused
3481 < 0 lost connection
3482 */
3483
3484 int
3485 smtp_setup_msg(void)
3486 {
3487 int done = 0;
3488 BOOL toomany = FALSE;
3489 BOOL discarded = FALSE;
3490 BOOL last_was_rej_mail = FALSE;
3491 BOOL last_was_rcpt = FALSE;
3492 void *reset_point = store_get(0);
3493
3494 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3495
3496 /* Reset for start of new message. We allow one RSET not to be counted as a
3497 nonmail command, for those MTAs that insist on sending it between every
3498 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3499 TLS between messages (an Exim client may do this if it has messages queued up
3500 for the host). Note: we do NOT reset AUTH at this point. */
3501
3502 smtp_reset(reset_point);
3503 message_ended = END_NOTSTARTED;
3504
3505 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3506
3507 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3508 cmd_list[CMD_LIST_HELO