Add $smtp_command_history variable
[exim.git] / src / src / smtp_in.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2017 */
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 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
308 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
309 static void smtp_quit_handler(uschar **, uschar **);
310 static void smtp_rset_handler(void);
311
312 /*************************************************
313 * Recheck synchronization *
314 *************************************************/
315
316 /* Synchronization checks can never be perfect because a packet may be on its
317 way but not arrived when the check is done. Normally, the checks happen when
318 commands are read: Exim ensures that there is no more input in the input buffer.
319 In normal cases, the response to the command will be fast, and there is no
320 further check.
321
322 However, for some commands an ACL is run, and that can include delays. In those
323 cases, it is useful to do another check on the input just before sending the
324 response. This also applies at the start of a connection. This function does
325 that check by means of the select() function, as long as the facility is not
326 disabled or inappropriate. A failure of select() is ignored.
327
328 When there is unwanted input, we read it so that it appears in the log of the
329 error.
330
331 Arguments: none
332 Returns: TRUE if all is well; FALSE if there is input pending
333 */
334
335 static BOOL
336 wouldblock_reading(void)
337 {
338 int fd, rc;
339 fd_set fds;
340 struct timeval tzero;
341
342 if (tls_in.active >= 0)
343 return !tls_could_read();
344
345 if (smtp_inptr < smtp_inend)
346 return FALSE;
347
348 fd = fileno(smtp_in);
349 FD_ZERO(&fds);
350 FD_SET(fd, &fds);
351 tzero.tv_sec = 0;
352 tzero.tv_usec = 0;
353 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
354
355 if (rc <= 0) return TRUE; /* Not ready to read */
356 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
357 if (rc < 0) return TRUE; /* End of file or error */
358
359 smtp_ungetc(rc);
360 rc = smtp_inend - smtp_inptr;
361 if (rc > 150) rc = 150;
362 smtp_inptr[rc] = 0;
363 return FALSE;
364 }
365
366 static BOOL
367 check_sync(void)
368 {
369 if (!smtp_enforce_sync || sender_host_address == NULL || sender_host_notsocket)
370 return TRUE;
371
372 return wouldblock_reading();
373 }
374
375
376 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
377 a reponse with the one following. */
378
379 static BOOL
380 pipeline_response(void)
381 {
382 if ( !smtp_enforce_sync || !sender_host_address
383 || sender_host_notsocket || !pipelining_advertised)
384 return FALSE;
385
386 return !wouldblock_reading();
387 }
388
389
390
391 /*************************************************
392 * Log incomplete transactions *
393 *************************************************/
394
395 /* This function is called after a transaction has been aborted by RSET, QUIT,
396 connection drops or other errors. It logs the envelope information received
397 so far in order to preserve address verification attempts.
398
399 Argument: string to indicate what aborted the transaction
400 Returns: nothing
401 */
402
403 static void
404 incomplete_transaction_log(uschar *what)
405 {
406 if (sender_address == NULL || /* No transaction in progress */
407 !LOGGING(smtp_incomplete_transaction))
408 return;
409
410 /* Build list of recipients for logging */
411
412 if (recipients_count > 0)
413 {
414 int i;
415 raw_recipients = store_get(recipients_count * sizeof(uschar *));
416 for (i = 0; i < recipients_count; i++)
417 raw_recipients[i] = recipients_list[i].address;
418 raw_recipients_count = recipients_count;
419 }
420
421 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
422 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
423 }
424
425
426
427
428 /* Refill the buffer, and notify DKIM verification code.
429 Return false for error or EOF.
430 */
431
432 static BOOL
433 smtp_refill(unsigned lim)
434 {
435 int rc, save_errno;
436 if (!smtp_out) return FALSE;
437 fflush(smtp_out);
438 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
439
440 /* Limit amount read, so non-message data is not fed to DKIM */
441
442 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE, lim));
443 save_errno = errno;
444 alarm(0);
445 if (rc <= 0)
446 {
447 /* Must put the error text in fixed store, because this might be during
448 header reading, where it releases unused store above the header. */
449 if (rc < 0)
450 {
451 smtp_had_error = save_errno;
452 smtp_read_error = string_copy_malloc(
453 string_sprintf(" (error: %s)", strerror(save_errno)));
454 }
455 else smtp_had_eof = 1;
456 return FALSE;
457 }
458 #ifndef DISABLE_DKIM
459 dkim_exim_verify_feed(smtp_inbuffer, rc);
460 #endif
461 smtp_inend = smtp_inbuffer + rc;
462 smtp_inptr = smtp_inbuffer;
463 return TRUE;
464 }
465
466 /*************************************************
467 * SMTP version of getc() *
468 *************************************************/
469
470 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
471 it flushes the output, and refills the buffer, with a timeout. The signal
472 handler is set appropriately by the calling function. This function is not used
473 after a connection has negotiated itself into an TLS/SSL state.
474
475 Arguments: lim Maximum amount to read/buffer
476 Returns: the next character or EOF
477 */
478
479 int
480 smtp_getc(unsigned lim)
481 {
482 if (smtp_inptr >= smtp_inend)
483 if (!smtp_refill(lim))
484 return EOF;
485 return *smtp_inptr++;
486 }
487
488 uschar *
489 smtp_getbuf(unsigned * len)
490 {
491 unsigned size;
492 uschar * buf;
493
494 if (smtp_inptr >= smtp_inend)
495 if (!smtp_refill(*len))
496 { *len = 0; return NULL; }
497
498 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
499 buf = smtp_inptr;
500 smtp_inptr += size;
501 *len = size;
502 return buf;
503 }
504
505 void
506 smtp_get_cache(void)
507 {
508 #ifndef DISABLE_DKIM
509 int n = smtp_inend - smtp_inptr;
510 if (n > 0)
511 dkim_exim_verify_feed(smtp_inptr, n);
512 #endif
513 }
514
515
516 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
517 previous BDAT chunk and getting new ones when we run out. Uses the
518 underlying smtp_getc or tls_getc both for that and for getting the
519 (buffered) data byte. EOD signals (an expected) no further data.
520 ERR signals a protocol error, and EOF a closed input stream.
521
522 Called from read_bdat_smtp() in receive.c for the message body, but also
523 by the headers read loop in receive_msg(); manipulates chunking_state
524 to handle the BDAT command/response.
525 Placed here due to the correlation with the above smtp_getc(), which it wraps,
526 and also by the need to do smtp command/response handling.
527
528 Arguments: lim (ignored)
529 Returns: the next character or ERR, EOD or EOF
530 */
531
532 int
533 bdat_getc(unsigned lim)
534 {
535 uschar * user_msg = NULL;
536 uschar * log_msg;
537
538 for(;;)
539 {
540 #ifndef DISABLE_DKIM
541 BOOL dkim_save;
542 #endif
543
544 if (chunking_data_left > 0)
545 return lwr_receive_getc(chunking_data_left--);
546
547 receive_getc = lwr_receive_getc;
548 receive_getbuf = lwr_receive_getbuf;
549 receive_ungetc = lwr_receive_ungetc;
550 #ifndef DISABLE_DKIM
551 dkim_save = dkim_collect_input;
552 dkim_collect_input = FALSE;
553 #endif
554
555 /* Unless PIPELINING was offered, there should be no next command
556 until after we ack that chunk */
557
558 if (!pipelining_advertised && !check_sync())
559 {
560 unsigned n = smtp_inend - smtp_inptr;
561 if (n > 32) n = 32;
562
563 incomplete_transaction_log(US"sync failure");
564 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
565 "(next input sent too soon: pipelining was not advertised): "
566 "rejected \"%s\" %s next input=\"%s\"",
567 smtp_cmd_buffer, host_and_ident(TRUE),
568 string_printing(string_copyn(smtp_inptr, n)));
569 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
570 US"SMTP synchronization error");
571 goto repeat_until_rset;
572 }
573
574 /* If not the last, ack the received chunk. The last response is delayed
575 until after the data ACL decides on it */
576
577 if (chunking_state == CHUNKING_LAST)
578 {
579 #ifndef DISABLE_DKIM
580 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
581 #endif
582 return EOD;
583 }
584
585 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
586 chunking_state = CHUNKING_OFFERED;
587 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
588
589 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
590 QUIT, RSET or NOOP but handling them seems obvious */
591
592 next_cmd:
593 switch(smtp_read_command(TRUE, 1))
594 {
595 default:
596 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
597 US"only BDAT permissible after non-LAST BDAT");
598
599 repeat_until_rset:
600 switch(smtp_read_command(TRUE, 1))
601 {
602 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
603 case EOF_CMD: return EOF;
604 case RSET_CMD: smtp_rset_handler(); return ERR;
605 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
606 US"only RSET accepted now") > 0)
607 return EOF;
608 goto repeat_until_rset;
609 }
610
611 case QUIT_CMD:
612 smtp_quit_handler(&user_msg, &log_msg);
613 /*FALLTHROUGH*/
614 case EOF_CMD:
615 return EOF;
616
617 case RSET_CMD:
618 smtp_rset_handler();
619 return ERR;
620
621 case NOOP_CMD:
622 HAD(SCH_NOOP);
623 smtp_printf("250 OK\r\n", FALSE);
624 goto next_cmd;
625
626 case BDAT_CMD:
627 {
628 int n;
629
630 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
631 {
632 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
633 US"missing size for BDAT command");
634 return ERR;
635 }
636 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
637 ? CHUNKING_LAST : CHUNKING_ACTIVE;
638 chunking_data_left = chunking_datasize;
639 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
640 (int)chunking_state, chunking_data_left);
641
642 if (chunking_datasize == 0)
643 if (chunking_state == CHUNKING_LAST)
644 return EOD;
645 else
646 {
647 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
648 US"zero size for BDAT command");
649 goto repeat_until_rset;
650 }
651
652 receive_getc = bdat_getc;
653 receive_getbuf = bdat_getbuf;
654 receive_ungetc = bdat_ungetc;
655 #ifndef DISABLE_DKIM
656 dkim_collect_input = dkim_save;
657 #endif
658 break; /* to top of main loop */
659 }
660 }
661 }
662 }
663
664 uschar *
665 bdat_getbuf(unsigned * len)
666 {
667 uschar * buf;
668
669 if (chunking_data_left <= 0)
670 { *len = 0; return NULL; }
671
672 if (*len > chunking_data_left) *len = chunking_data_left;
673 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
674 chunking_data_left -= *len;
675 return buf;
676 }
677
678 void
679 bdat_flush_data(void)
680 {
681 unsigned n = chunking_data_left;
682 (void) bdat_getbuf(&n);
683
684 receive_getc = lwr_receive_getc;
685 receive_getbuf = lwr_receive_getbuf;
686 receive_ungetc = lwr_receive_ungetc;
687
688 if (chunking_state != CHUNKING_LAST)
689 {
690 chunking_state = CHUNKING_OFFERED;
691 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
692 }
693 }
694
695
696
697
698 /*************************************************
699 * SMTP version of ungetc() *
700 *************************************************/
701
702 /* Puts a character back in the input buffer. Only ever
703 called once.
704
705 Arguments:
706 ch the character
707
708 Returns: the character
709 */
710
711 int
712 smtp_ungetc(int ch)
713 {
714 *--smtp_inptr = ch;
715 return ch;
716 }
717
718
719 int
720 bdat_ungetc(int ch)
721 {
722 chunking_data_left++;
723 return lwr_receive_ungetc(ch);
724 }
725
726
727
728 /*************************************************
729 * SMTP version of feof() *
730 *************************************************/
731
732 /* Tests for a previous EOF
733
734 Arguments: none
735 Returns: non-zero if the eof flag is set
736 */
737
738 int
739 smtp_feof(void)
740 {
741 return smtp_had_eof;
742 }
743
744
745
746
747 /*************************************************
748 * SMTP version of ferror() *
749 *************************************************/
750
751 /* Tests for a previous read error, and returns with errno
752 restored to what it was when the error was detected.
753
754 Arguments: none
755 Returns: non-zero if the error flag is set
756 */
757
758 int
759 smtp_ferror(void)
760 {
761 errno = smtp_had_error;
762 return smtp_had_error;
763 }
764
765
766
767 /*************************************************
768 * Test for characters in the SMTP buffer *
769 *************************************************/
770
771 /* Used at the end of a message
772
773 Arguments: none
774 Returns: TRUE/FALSE
775 */
776
777 BOOL
778 smtp_buffered(void)
779 {
780 return smtp_inptr < smtp_inend;
781 }
782
783
784
785 /*************************************************
786 * Write formatted string to SMTP channel *
787 *************************************************/
788
789 /* This is a separate function so that we don't have to repeat everything for
790 TLS support or debugging. It is global so that the daemon and the
791 authentication functions can use it. It does not return any error indication,
792 because major problems such as dropped connections won't show up till an output
793 flush for non-TLS connections. The smtp_fflush() function is available for
794 checking that: for convenience, TLS output errors are remembered here so that
795 they are also picked up later by smtp_fflush().
796
797 Arguments:
798 format format string
799 more further data expected
800 ... optional arguments
801
802 Returns: nothing
803 */
804
805 void
806 smtp_printf(const char *format, BOOL more, ...)
807 {
808 va_list ap;
809
810 va_start(ap, more);
811 smtp_vprintf(format, more, ap);
812 va_end(ap);
813 }
814
815 /* This is split off so that verify.c:respond_printf() can, in effect, call
816 smtp_printf(), bearing in mind that in C a vararg function can't directly
817 call another vararg function, only a function which accepts a va_list. */
818
819 void
820 smtp_vprintf(const char *format, BOOL more, va_list ap)
821 {
822 BOOL yield;
823
824 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
825
826 DEBUG(D_receive)
827 {
828 void *reset_point = store_get(0);
829 uschar *msg_copy, *cr, *end;
830 msg_copy = string_copy(big_buffer);
831 end = msg_copy + Ustrlen(msg_copy);
832 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
833 memmove(cr, cr + 1, (end--) - cr);
834 debug_printf("SMTP>> %s", msg_copy);
835 store_reset(reset_point);
836 }
837
838 if (!yield)
839 {
840 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
841 smtp_closedown(US"Unexpected error");
842 exim_exit(EXIT_FAILURE);
843 }
844
845 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
846 have had the same. Note: this code is also present in smtp_respond(). It would
847 be tidier to have it only in one place, but when it was added, it was easier to
848 do it that way, so as not to have to mess with the code for the RCPT command,
849 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
850
851 if (rcpt_in_progress)
852 {
853 if (rcpt_smtp_response == NULL)
854 rcpt_smtp_response = string_copy(big_buffer);
855 else if (rcpt_smtp_response_same &&
856 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
857 rcpt_smtp_response_same = FALSE;
858 rcpt_in_progress = FALSE;
859 }
860
861 /* Now write the string */
862
863 #ifdef SUPPORT_TLS
864 if (tls_in.active >= 0)
865 {
866 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer), more) < 0)
867 smtp_write_error = -1;
868 }
869 else
870 #endif
871
872 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
873 }
874
875
876
877 /*************************************************
878 * Flush SMTP out and check for error *
879 *************************************************/
880
881 /* This function isn't currently used within Exim (it detects errors when it
882 tries to read the next SMTP input), but is available for use in local_scan().
883 For non-TLS connections, it flushes the output and checks for errors. For
884 TLS-connections, it checks for a previously-detected TLS write error.
885
886 Arguments: none
887 Returns: 0 for no error; -1 after an error
888 */
889
890 int
891 smtp_fflush(void)
892 {
893 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
894 return smtp_write_error;
895 }
896
897
898
899 /*************************************************
900 * SMTP command read timeout *
901 *************************************************/
902
903 /* Signal handler for timing out incoming SMTP commands. This attempts to
904 finish off tidily.
905
906 Argument: signal number (SIGALRM)
907 Returns: nothing
908 */
909
910 static void
911 command_timeout_handler(int sig)
912 {
913 sig = sig; /* Keep picky compilers happy */
914 log_write(L_lost_incoming_connection,
915 LOG_MAIN, "SMTP command timeout on%s connection from %s",
916 (tls_in.active >= 0)? " TLS" : "",
917 host_and_ident(FALSE));
918 if (smtp_batched_input)
919 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
920 smtp_notquit_exit(US"command-timeout", US"421",
921 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
922 exim_exit(EXIT_FAILURE);
923 }
924
925
926
927 /*************************************************
928 * SIGTERM received *
929 *************************************************/
930
931 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
932
933 Argument: signal number (SIGTERM)
934 Returns: nothing
935 */
936
937 static void
938 command_sigterm_handler(int sig)
939 {
940 sig = sig; /* Keep picky compilers happy */
941 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
942 if (smtp_batched_input)
943 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
944 smtp_notquit_exit(US"signal-exit", US"421",
945 US"%s: Service not available - closing connection", smtp_active_hostname);
946 exim_exit(EXIT_FAILURE);
947 }
948
949
950
951
952 #ifdef SUPPORT_PROXY
953 /*************************************************
954 * Restore socket timeout to previous value *
955 *************************************************/
956 /* If the previous value was successfully retrieved, restore
957 it before returning control to the non-proxy routines
958
959 Arguments: fd - File descriptor for input
960 get_ok - Successfully retrieved previous values
961 tvtmp - Time struct with previous values
962 vslen - Length of time struct
963 Returns: none
964 */
965 static void
966 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
967 {
968 if (get_ok == 0)
969 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
970 }
971
972 /*************************************************
973 * Check if host is required proxy host *
974 *************************************************/
975 /* The function determines if inbound host will be a regular smtp host
976 or if it is configured that it must use Proxy Protocol. A local
977 connection cannot.
978
979 Arguments: none
980 Returns: bool
981 */
982
983 static BOOL
984 check_proxy_protocol_host()
985 {
986 int rc;
987
988 if ( sender_host_address
989 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
990 sender_host_address, NULL)) == OK)
991 {
992 DEBUG(D_receive)
993 debug_printf("Detected proxy protocol configured host\n");
994 proxy_session = TRUE;
995 }
996 return proxy_session;
997 }
998
999
1000 /*************************************************
1001 * Read data until newline or end of buffer *
1002 *************************************************/
1003 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1004 read an entire buffer and assume there will be nothing past a proxy protocol
1005 header. Our approach normally is to use stdio, but again that relies upon
1006 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1007 reading _nothing_ before client TLS handshake. So we don't want to use the
1008 usual buffering reads which may read enough to block TLS starting.
1009
1010 So unfortunately we're down to "read one byte at a time, with a syscall each,
1011 and expect a little overhead", for all proxy-opened connections which are v1,
1012 just to handle the TLS-on-connect case. Since SSL functions wrap the
1013 underlying fd, we can't assume that we can feed them any already-read content.
1014
1015 We need to know where to read to, the max capacity, and we'll read until we
1016 get a CR and one more character. Let the caller scream if it's CR+!LF.
1017
1018 Return the amount read.
1019 */
1020
1021 static int
1022 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1023 {
1024 uschar *to = base + already;
1025 uschar *cr;
1026 int have = 0;
1027 int ret;
1028 int last = 0;
1029
1030 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1031 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1032
1033 cr = memchr(base, '\r', already);
1034 if (cr != NULL)
1035 {
1036 if ((cr - base) < already - 1)
1037 {
1038 /* \r and presumed \n already within what we have; probably not
1039 actually proxy protocol, but abort cleanly. */
1040 return 0;
1041 }
1042 /* \r is last character read, just need one more. */
1043 last = 1;
1044 }
1045
1046 while (capacity > 0)
1047 {
1048 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1049 if (ret == -1)
1050 return -1;
1051 have++;
1052 if (last)
1053 return have;
1054 if (*to == '\r')
1055 last = 1;
1056 capacity--;
1057 to++;
1058 }
1059
1060 /* reached end without having room for a final newline, abort */
1061 errno = EOVERFLOW;
1062 return -1;
1063 }
1064
1065 /*************************************************
1066 * Setup host for proxy protocol *
1067 *************************************************/
1068 /* The function configures the connection based on a header from the
1069 inbound host to use Proxy Protocol. The specification is very exact
1070 so exit with an error if do not find the exact required pieces. This
1071 includes an incorrect number of spaces separating args.
1072
1073 Arguments: none
1074 Returns: Boolean success
1075 */
1076
1077 static void
1078 setup_proxy_protocol_host()
1079 {
1080 union {
1081 struct {
1082 uschar line[108];
1083 } v1;
1084 struct {
1085 uschar sig[12];
1086 uint8_t ver_cmd;
1087 uint8_t fam;
1088 uint16_t len;
1089 union {
1090 struct { /* TCP/UDP over IPv4, len = 12 */
1091 uint32_t src_addr;
1092 uint32_t dst_addr;
1093 uint16_t src_port;
1094 uint16_t dst_port;
1095 } ip4;
1096 struct { /* TCP/UDP over IPv6, len = 36 */
1097 uint8_t src_addr[16];
1098 uint8_t dst_addr[16];
1099 uint16_t src_port;
1100 uint16_t dst_port;
1101 } ip6;
1102 struct { /* AF_UNIX sockets, len = 216 */
1103 uschar src_addr[108];
1104 uschar dst_addr[108];
1105 } unx;
1106 } addr;
1107 } v2;
1108 } hdr;
1109
1110 /* Temp variables used in PPv2 address:port parsing */
1111 uint16_t tmpport;
1112 char tmpip[INET_ADDRSTRLEN];
1113 struct sockaddr_in tmpaddr;
1114 char tmpip6[INET6_ADDRSTRLEN];
1115 struct sockaddr_in6 tmpaddr6;
1116
1117 /* We can't read "all data until end" because while SMTP is
1118 server-speaks-first, the TLS handshake is client-speaks-first, so for
1119 TLS-on-connect ports the proxy protocol header will usually be immediately
1120 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1121 reinject data for reading by those. So instead we first read "enough to be
1122 safely read within the header, and figure out how much more to read".
1123 For v1 we will later read to the end-of-line, for v2 we will read based upon
1124 the stated length.
1125
1126 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1127 data is needed total. For v1, where the line looks like:
1128 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1129
1130 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1131 We seem to support that. So, if we read 14 octets then we can tell if we're
1132 v2 or v1. If we're v1, we can continue reading as normal.
1133
1134 If we're v2, we can't slurp up the entire header. We need the length in the
1135 15th & 16th octets, then to read everything after that.
1136
1137 So to safely handle v1 and v2, with client-sent-first supported correctly,
1138 we have to do a minimum of 3 read calls, not 1. Eww.
1139 */
1140
1141 #define PROXY_INITIAL_READ 14
1142 #define PROXY_V2_HEADER_SIZE 16
1143 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1144 # error Code bug in sizes of data to read for proxy usage
1145 #endif
1146
1147 int get_ok = 0;
1148 int size, ret;
1149 int fd = fileno(smtp_in);
1150 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1151 uschar * iptype; /* To display debug info */
1152 struct timeval tv;
1153 struct timeval tvtmp;
1154 socklen_t vslen = sizeof(struct timeval);
1155 BOOL yield = FALSE;
1156
1157 /* Save current socket timeout values */
1158 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1159
1160 /* Proxy Protocol host must send header within a short time
1161 (default 3 seconds) or it's considered invalid */
1162 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1163 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1164 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1165 goto bad;
1166
1167 do
1168 {
1169 /* The inbound host was declared to be a Proxy Protocol host, so
1170 don't do a PEEK into the data, actually slurp up enough to be
1171 "safe". Can't take it all because TLS-on-connect clients follow
1172 immediately with TLS handshake. */
1173 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1174 }
1175 while (ret == -1 && errno == EINTR);
1176
1177 if (ret == -1)
1178 goto proxyfail;
1179
1180 /* For v2, handle reading the length, and then the rest. */
1181 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1182 {
1183 int retmore;
1184 uint8_t ver;
1185
1186 /* First get the length fields. */
1187 do
1188 {
1189 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1190 } while (retmore == -1 && errno == EINTR);
1191 if (retmore == -1)
1192 goto proxyfail;
1193 ret += retmore;
1194
1195 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1196
1197 /* May 2014: haproxy combined the version and command into one byte to
1198 allow two full bytes for the length field in order to proxy SSL
1199 connections. SSL Proxy is not supported in this version of Exim, but
1200 must still separate values here. */
1201
1202 if (ver != 0x02)
1203 {
1204 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1205 goto proxyfail;
1206 }
1207
1208 /* The v2 header will always be 16 bytes per the spec. */
1209 size = 16 + ntohs(hdr.v2.len);
1210 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1211 size, (int)sizeof(hdr));
1212
1213 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1214 amount that we need. Double-check that the size is not unreasonable, then
1215 get the rest. */
1216 if (size > sizeof(hdr))
1217 {
1218 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1219 goto proxyfail;
1220 }
1221
1222 do
1223 {
1224 do
1225 {
1226 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1227 } while (retmore == -1 && errno == EINTR);
1228 if (retmore == -1)
1229 goto proxyfail;
1230 ret += retmore;
1231 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1232 } while (ret < size);
1233
1234 } /* end scope for getting rest of data for v2 */
1235
1236 /* At this point: if PROXYv2, we've read the exact size required for all data;
1237 if PROXYv1 then we've read "less than required for any valid line" and should
1238 read the rest". */
1239
1240 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1241 {
1242 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1243
1244 switch (cmd)
1245 {
1246 case 0x01: /* PROXY command */
1247 switch (hdr.v2.fam)
1248 {
1249 case 0x11: /* TCPv4 address type */
1250 iptype = US"IPv4";
1251 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1252 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1253 if (!string_is_ip_address(US tmpip, NULL))
1254 {
1255 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1256 goto proxyfail;
1257 }
1258 proxy_local_address = sender_host_address;
1259 sender_host_address = string_copy(US tmpip);
1260 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1261 proxy_local_port = sender_host_port;
1262 sender_host_port = tmpport;
1263 /* Save dest ip/port */
1264 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1265 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1266 if (!string_is_ip_address(US tmpip, NULL))
1267 {
1268 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1269 goto proxyfail;
1270 }
1271 proxy_external_address = string_copy(US tmpip);
1272 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1273 proxy_external_port = tmpport;
1274 goto done;
1275 case 0x21: /* TCPv6 address type */
1276 iptype = US"IPv6";
1277 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1278 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1279 if (!string_is_ip_address(US tmpip6, NULL))
1280 {
1281 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1282 goto proxyfail;
1283 }
1284 proxy_local_address = sender_host_address;
1285 sender_host_address = string_copy(US tmpip6);
1286 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1287 proxy_local_port = sender_host_port;
1288 sender_host_port = tmpport;
1289 /* Save dest ip/port */
1290 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1291 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1292 if (!string_is_ip_address(US tmpip6, NULL))
1293 {
1294 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1295 goto proxyfail;
1296 }
1297 proxy_external_address = string_copy(US tmpip6);
1298 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1299 proxy_external_port = tmpport;
1300 goto done;
1301 default:
1302 DEBUG(D_receive)
1303 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1304 hdr.v2.fam);
1305 goto proxyfail;
1306 }
1307 /* Unsupported protocol, keep local connection address */
1308 break;
1309 case 0x00: /* LOCAL command */
1310 /* Keep local connection address for LOCAL */
1311 iptype = US"local";
1312 break;
1313 default:
1314 DEBUG(D_receive)
1315 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1316 goto proxyfail;
1317 }
1318 }
1319 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1320 {
1321 uschar *p;
1322 uschar *end;
1323 uschar *sp; /* Utility variables follow */
1324 int tmp_port;
1325 int r2;
1326 char *endc;
1327
1328 /* get the rest of the line */
1329 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1330 if (r2 == -1)
1331 goto proxyfail;
1332 ret += r2;
1333
1334 p = string_copy(hdr.v1.line);
1335 end = memchr(p, '\r', ret - 1);
1336
1337 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1338 {
1339 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1340 goto proxyfail;
1341 }
1342 *end = '\0'; /* Terminate the string */
1343 size = end + 2 - p; /* Skip header + CRLF */
1344 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1345 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1346 /* Step through the string looking for the required fields. Ensure
1347 strict adherence to required formatting, exit for any error. */
1348 p += 5;
1349 if (!isspace(*(p++)))
1350 {
1351 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1352 goto proxyfail;
1353 }
1354 if (!Ustrncmp(p, CCS"TCP4", 4))
1355 iptype = US"IPv4";
1356 else if (!Ustrncmp(p,CCS"TCP6", 4))
1357 iptype = US"IPv6";
1358 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1359 {
1360 iptype = US"Unknown";
1361 goto done;
1362 }
1363 else
1364 {
1365 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1366 goto proxyfail;
1367 }
1368
1369 p += Ustrlen(iptype);
1370 if (!isspace(*(p++)))
1371 {
1372 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1373 goto proxyfail;
1374 }
1375 /* Find the end of the arg */
1376 if ((sp = Ustrchr(p, ' ')) == NULL)
1377 {
1378 DEBUG(D_receive)
1379 debug_printf("Did not find proxied src %s\n", iptype);
1380 goto proxyfail;
1381 }
1382 *sp = '\0';
1383 if(!string_is_ip_address(p, NULL))
1384 {
1385 DEBUG(D_receive)
1386 debug_printf("Proxied src arg is not an %s address\n", iptype);
1387 goto proxyfail;
1388 }
1389 proxy_local_address = sender_host_address;
1390 sender_host_address = p;
1391 p = sp + 1;
1392 if ((sp = Ustrchr(p, ' ')) == NULL)
1393 {
1394 DEBUG(D_receive)
1395 debug_printf("Did not find proxy dest %s\n", iptype);
1396 goto proxyfail;
1397 }
1398 *sp = '\0';
1399 if(!string_is_ip_address(p, NULL))
1400 {
1401 DEBUG(D_receive)
1402 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1403 goto proxyfail;
1404 }
1405 proxy_external_address = p;
1406 p = sp + 1;
1407 if ((sp = Ustrchr(p, ' ')) == NULL)
1408 {
1409 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1410 goto proxyfail;
1411 }
1412 *sp = '\0';
1413 tmp_port = strtol(CCS p, &endc, 10);
1414 if (*endc || tmp_port == 0)
1415 {
1416 DEBUG(D_receive)
1417 debug_printf("Proxied src port '%s' not an integer\n", p);
1418 goto proxyfail;
1419 }
1420 proxy_local_port = sender_host_port;
1421 sender_host_port = tmp_port;
1422 p = sp + 1;
1423 if ((sp = Ustrchr(p, '\0')) == NULL)
1424 {
1425 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1426 goto proxyfail;
1427 }
1428 tmp_port = strtol(CCS p, &endc, 10);
1429 if (*endc || tmp_port == 0)
1430 {
1431 DEBUG(D_receive)
1432 debug_printf("Proxy dest port '%s' not an integer\n", p);
1433 goto proxyfail;
1434 }
1435 proxy_external_port = tmp_port;
1436 /* Already checked for /r /n above. Good V1 header received. */
1437 }
1438 else
1439 {
1440 /* Wrong protocol */
1441 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1442 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1443 goto proxyfail;
1444 }
1445
1446 done:
1447 DEBUG(D_receive)
1448 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1449 yield = proxy_session;
1450
1451 /* Don't flush any potential buffer contents. Any input on proxyfail
1452 should cause a synchronization failure */
1453
1454 proxyfail:
1455 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1456
1457 bad:
1458 if (yield)
1459 {
1460 sender_host_name = NULL;
1461 (void) host_name_lookup();
1462 host_build_sender_fullhost();
1463 }
1464 else
1465 {
1466 proxy_session_failed = TRUE;
1467 DEBUG(D_receive)
1468 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1469 }
1470
1471 return;
1472 }
1473 #endif
1474
1475 /*************************************************
1476 * Read one command line *
1477 *************************************************/
1478
1479 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1480 There are sites that don't do this, and in any case internal SMTP probably
1481 should check only for LF. Consequently, we check here for LF only. The line
1482 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1483 an unknown command. The command is read into the global smtp_cmd_buffer so that
1484 it is available via $smtp_command.
1485
1486 The character reading routine sets up a timeout for each block actually read
1487 from the input (which may contain more than one command). We set up a special
1488 signal handler that closes down the session on a timeout. Control does not
1489 return when it runs.
1490
1491 Arguments:
1492 check_sync if TRUE, check synchronization rules if global option is TRUE
1493 buffer_lim maximum to buffer in lower layer
1494
1495 Returns: a code identifying the command (enumerated above)
1496 */
1497
1498 static int
1499 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1500 {
1501 int c;
1502 int ptr = 0;
1503 smtp_cmd_list *p;
1504 BOOL hadnull = FALSE;
1505
1506 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1507
1508 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1509 {
1510 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1511 {
1512 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1513 return OTHER_CMD;
1514 }
1515 if (c == 0)
1516 {
1517 hadnull = TRUE;
1518 c = '?';
1519 }
1520 smtp_cmd_buffer[ptr++] = c;
1521 }
1522
1523 receive_linecount++; /* For BSMTP errors */
1524 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1525
1526 /* If hit end of file, return pseudo EOF command. Whether we have a
1527 part-line already read doesn't matter, since this is an error state. */
1528
1529 if (c == EOF) return EOF_CMD;
1530
1531 /* Remove any CR and white space at the end of the line, and terminate the
1532 string. */
1533
1534 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1535 smtp_cmd_buffer[ptr] = 0;
1536
1537 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1538
1539 /* NULLs are not allowed in SMTP commands */
1540
1541 if (hadnull) return BADCHAR_CMD;
1542
1543 /* Scan command list and return identity, having set the data pointer
1544 to the start of the actual data characters. Check for SMTP synchronization
1545 if required. */
1546
1547 for (p = cmd_list; p < cmd_list_end; p++)
1548 {
1549 #ifdef SUPPORT_PROXY
1550 /* Only allow QUIT command if Proxy Protocol parsing failed */
1551 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1552 continue;
1553 #endif
1554 if ( p->len
1555 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1556 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1557 || smtp_cmd_buffer[p->len] == 0
1558 || smtp_cmd_buffer[p->len] == ' '
1559 ) )
1560 {
1561 if (smtp_inptr < smtp_inend && /* Outstanding input */
1562 p->cmd < sync_cmd_limit && /* Command should sync */
1563 check_sync && /* Local flag set */
1564 smtp_enforce_sync && /* Global flag set */
1565 sender_host_address != NULL && /* Not local input */
1566 !sender_host_notsocket) /* Really is a socket */
1567 return BADSYN_CMD;
1568
1569 /* The variables $smtp_command and $smtp_command_argument point into the
1570 unmodified input buffer. A copy of the latter is taken for actual
1571 processing, so that it can be chopped up into separate parts if necessary,
1572 for example, when processing a MAIL command options such as SIZE that can
1573 follow the sender address. */
1574
1575 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1576 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1577 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1578 smtp_cmd_data = smtp_data_buffer;
1579
1580 /* Count non-mail commands from those hosts that are controlled in this
1581 way. The default is all hosts. We don't waste effort checking the list
1582 until we get a non-mail command, but then cache the result to save checking
1583 again. If there's a DEFER while checking the host, assume it's in the list.
1584
1585 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1586 start of each incoming message by fiddling with the value in the table. */
1587
1588 if (!p->is_mail_cmd)
1589 {
1590 if (count_nonmail == TRUE_UNSET) count_nonmail =
1591 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1592 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1593 return TOO_MANY_NONMAIL_CMD;
1594 }
1595
1596 /* If there is data for a command that does not expect it, generate the
1597 error here. */
1598
1599 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1600 }
1601 }
1602
1603 #ifdef SUPPORT_PROXY
1604 /* Only allow QUIT command if Proxy Protocol parsing failed */
1605 if (proxy_session && proxy_session_failed)
1606 return PROXY_FAIL_IGNORE_CMD;
1607 #endif
1608
1609 /* Enforce synchronization for unknown commands */
1610
1611 if (smtp_inptr < smtp_inend && /* Outstanding input */
1612 check_sync && /* Local flag set */
1613 smtp_enforce_sync && /* Global flag set */
1614 sender_host_address != NULL && /* Not local input */
1615 !sender_host_notsocket) /* Really is a socket */
1616 return BADSYN_CMD;
1617
1618 return OTHER_CMD;
1619 }
1620
1621
1622
1623 /*************************************************
1624 * Forced closedown of call *
1625 *************************************************/
1626
1627 /* This function is called from log.c when Exim is dying because of a serious
1628 disaster, and also from some other places. If an incoming non-batched SMTP
1629 channel is open, it swallows the rest of the incoming message if in the DATA
1630 phase, sends the reply string, and gives an error to all subsequent commands
1631 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1632 smtp_in.
1633
1634 Arguments:
1635 message SMTP reply string to send, excluding the code
1636
1637 Returns: nothing
1638 */
1639
1640 void
1641 smtp_closedown(uschar *message)
1642 {
1643 if (smtp_in == NULL || smtp_batched_input) return;
1644 receive_swallow_smtp();
1645 smtp_printf("421 %s\r\n", FALSE, message);
1646
1647 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1648 {
1649 case EOF_CMD:
1650 return;
1651
1652 case QUIT_CMD:
1653 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1654 mac_smtp_fflush();
1655 return;
1656
1657 case RSET_CMD:
1658 smtp_printf("250 Reset OK\r\n", FALSE);
1659 break;
1660
1661 default:
1662 smtp_printf("421 %s\r\n", FALSE, message);
1663 break;
1664 }
1665 }
1666
1667
1668
1669
1670 /*************************************************
1671 * Set up connection info for logging *
1672 *************************************************/
1673
1674 /* This function is called when logging information about an SMTP connection.
1675 It sets up appropriate source information, depending on the type of connection.
1676 If sender_fullhost is NULL, we are at a very early stage of the connection;
1677 just use the IP address.
1678
1679 Argument: none
1680 Returns: a string describing the connection
1681 */
1682
1683 uschar *
1684 smtp_get_connection_info(void)
1685 {
1686 const uschar * hostname = sender_fullhost
1687 ? sender_fullhost : sender_host_address;
1688
1689 if (host_checking)
1690 return string_sprintf("SMTP connection from %s", hostname);
1691
1692 if (sender_host_unknown || sender_host_notsocket)
1693 return string_sprintf("SMTP connection from %s", sender_ident);
1694
1695 if (is_inetd)
1696 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1697
1698 if (LOGGING(incoming_interface) && interface_address != NULL)
1699 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1700 interface_address, interface_port);
1701
1702 return string_sprintf("SMTP connection from %s", hostname);
1703 }
1704
1705
1706
1707 #ifdef SUPPORT_TLS
1708 /* Append TLS-related information to a log line
1709
1710 Arguments:
1711 s String under construction: allocated string to extend, or NULL
1712 sizep Pointer to current allocation size (update on return), or NULL
1713 ptrp Pointer to index for new entries in string (update on return), or NULL
1714
1715 Returns: Allocated string or NULL
1716 */
1717 static uschar *
1718 s_tlslog(uschar * s, int * sizep, int * ptrp)
1719 {
1720 int size = sizep ? *sizep : 0;
1721 int ptr = ptrp ? *ptrp : 0;
1722
1723 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1724 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1725 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1726 s = string_append(s, &size, &ptr, 2, US" CV=",
1727 tls_in.certificate_verified? "yes":"no");
1728 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1729 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1730 string_printing(tls_in.peerdn), US"\"");
1731 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1732 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1733 string_printing(tls_in.sni), US"\"");
1734
1735 if (s)
1736 {
1737 s[ptr] = '\0';
1738 if (sizep) *sizep = size;
1739 if (ptrp) *ptrp = ptr;
1740 }
1741 return s;
1742 }
1743 #endif
1744
1745 /*************************************************
1746 * Log lack of MAIL if so configured *
1747 *************************************************/
1748
1749 /* This function is called when an SMTP session ends. If the log selector
1750 smtp_no_mail is set, write a log line giving some details of what has happened
1751 in the SMTP session.
1752
1753 Arguments: none
1754 Returns: nothing
1755 */
1756
1757 void
1758 smtp_log_no_mail(void)
1759 {
1760 int size, ptr, i;
1761 uschar *s, *sep;
1762
1763 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1764 return;
1765
1766 s = NULL;
1767 size = ptr = 0;
1768
1769 if (sender_host_authenticated != NULL)
1770 {
1771 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1772 if (authenticated_id != NULL)
1773 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1774 }
1775
1776 #ifdef SUPPORT_TLS
1777 s = s_tlslog(s, &size, &ptr);
1778 #endif
1779
1780 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1781 US" C=..." : US" C=";
1782 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1783 {
1784 if (smtp_connection_had[i] != SCH_NONE)
1785 {
1786 s = string_append(s, &size, &ptr, 2, sep,
1787 smtp_names[smtp_connection_had[i]]);
1788 sep = US",";
1789 }
1790 }
1791
1792 for (i = 0; i < smtp_ch_index; i++)
1793 {
1794 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1795 sep = US",";
1796 }
1797
1798 if (s) s[ptr] = 0; else s = US"";
1799 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1800 host_and_ident(FALSE),
1801 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1802 s);
1803 }
1804
1805
1806 /* Return list of recent smtp commands */
1807
1808 uschar *
1809 smtp_cmd_hist(void)
1810 {
1811 uschar * list = NULL;
1812 int size = 0, len = 0, i;
1813
1814 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1815 if (smtp_connection_had[i] != SCH_NONE)
1816 list = string_append_listele(list, &size, &len, ',',
1817 smtp_names[smtp_connection_had[i]]);
1818 for (i = 0; i < smtp_ch_index; i++)
1819 list = string_append_listele(list, &size, &len, ',',
1820 smtp_names[smtp_connection_had[i]]);
1821 return list ? list : US"";
1822 }
1823
1824
1825
1826
1827 /*************************************************
1828 * Check HELO line and set sender_helo_name *
1829 *************************************************/
1830
1831 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1832 the domain name of the sending host, or an ip literal in square brackets. The
1833 argument is placed in sender_helo_name, which is in malloc store, because it
1834 must persist over multiple incoming messages. If helo_accept_junk is set, this
1835 host is permitted to send any old junk (needed for some broken hosts).
1836 Otherwise, helo_allow_chars can be used for rogue characters in general
1837 (typically people want to let in underscores).
1838
1839 Argument:
1840 s the data portion of the line (already past any white space)
1841
1842 Returns: TRUE or FALSE
1843 */
1844
1845 static BOOL
1846 check_helo(uschar *s)
1847 {
1848 uschar *start = s;
1849 uschar *end = s + Ustrlen(s);
1850 BOOL yield = helo_accept_junk;
1851
1852 /* Discard any previous helo name */
1853
1854 if (sender_helo_name != NULL)
1855 {
1856 store_free(sender_helo_name);
1857 sender_helo_name = NULL;
1858 }
1859
1860 /* Skip tests if junk is permitted. */
1861
1862 if (!yield)
1863 {
1864 /* Allow the new standard form for IPv6 address literals, namely,
1865 [IPv6:....], and because someone is bound to use it, allow an equivalent
1866 IPv4 form. Allow plain addresses as well. */
1867
1868 if (*s == '[')
1869 {
1870 if (end[-1] == ']')
1871 {
1872 end[-1] = 0;
1873 if (strncmpic(s, US"[IPv6:", 6) == 0)
1874 yield = (string_is_ip_address(s+6, NULL) == 6);
1875 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1876 yield = (string_is_ip_address(s+6, NULL) == 4);
1877 else
1878 yield = (string_is_ip_address(s+1, NULL) != 0);
1879 end[-1] = ']';
1880 }
1881 }
1882
1883 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1884 that have been configured (usually underscore - sigh). */
1885
1886 else if (*s != 0)
1887 {
1888 yield = TRUE;
1889 while (*s != 0)
1890 {
1891 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1892 Ustrchr(helo_allow_chars, *s) == NULL)
1893 {
1894 yield = FALSE;
1895 break;
1896 }
1897 s++;
1898 }
1899 }
1900 }
1901
1902 /* Save argument if OK */
1903
1904 if (yield) sender_helo_name = string_copy_malloc(start);
1905 return yield;
1906 }
1907
1908
1909
1910
1911
1912 /*************************************************
1913 * Extract SMTP command option *
1914 *************************************************/
1915
1916 /* This function picks the next option setting off the end of smtp_cmd_data. It
1917 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1918 things that can appear there.
1919
1920 Arguments:
1921 name point this at the name
1922 value point this at the data string
1923
1924 Returns: TRUE if found an option
1925 */
1926
1927 static BOOL
1928 extract_option(uschar **name, uschar **value)
1929 {
1930 uschar *n;
1931 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1932 while (isspace(*v)) v--;
1933 v[1] = 0;
1934 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1935 {
1936 /* Take care to not stop at a space embedded in a quoted local-part */
1937
1938 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1939 v--;
1940 }
1941
1942 n = v;
1943 if (*v == '=')
1944 {
1945 while(isalpha(n[-1])) n--;
1946 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1947 if (!isspace(n[-1])) return FALSE;
1948 n[-1] = 0;
1949 }
1950 else
1951 {
1952 n++;
1953 if (v == smtp_cmd_data) return FALSE;
1954 }
1955 *v++ = 0;
1956 *name = n;
1957 *value = v;
1958 return TRUE;
1959 }
1960
1961
1962
1963
1964
1965 /*************************************************
1966 * Reset for new message *
1967 *************************************************/
1968
1969 /* This function is called whenever the SMTP session is reset from
1970 within either of the setup functions.
1971
1972 Argument: the stacking pool storage reset point
1973 Returns: nothing
1974 */
1975
1976 static void
1977 smtp_reset(void *reset_point)
1978 {
1979 recipients_list = NULL;
1980 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1981 raw_recipients_count = recipients_count = recipients_list_max = 0;
1982 message_linecount = 0;
1983 message_size = -1;
1984 acl_added_headers = NULL;
1985 acl_removed_headers = NULL;
1986 queue_only_policy = FALSE;
1987 rcpt_smtp_response = NULL;
1988 rcpt_smtp_response_same = TRUE;
1989 rcpt_in_progress = FALSE;
1990 deliver_freeze = FALSE; /* Can be set by ACL */
1991 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1992 fake_response = OK; /* Can be set by ACL */
1993 #ifdef WITH_CONTENT_SCAN
1994 no_mbox_unspool = FALSE; /* Can be set by ACL */
1995 #endif
1996 submission_mode = FALSE; /* Can be set by ACL */
1997 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1998 active_local_from_check = local_from_check; /* Can be set by ACL */
1999 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2000 sending_ip_address = NULL;
2001 return_path = sender_address = NULL;
2002 sender_data = NULL; /* Can be set by ACL */
2003 deliver_localpart_orig = NULL;
2004 deliver_domain_orig = NULL;
2005 callout_address = NULL;
2006 submission_name = NULL; /* Can be set by ACL */
2007 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2008 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2009 sender_verified_list = NULL; /* No senders verified */
2010 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2011 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2012
2013 authenticated_sender = NULL;
2014 #ifdef EXPERIMENTAL_BRIGHTMAIL
2015 bmi_run = 0;
2016 bmi_verdicts = NULL;
2017 #endif
2018 dnslist_domain = dnslist_matched = NULL;
2019 #ifndef DISABLE_DKIM
2020 dkim_signers = NULL;
2021 dkim_disable_verify = FALSE;
2022 dkim_collect_input = FALSE;
2023 #endif
2024 dsn_ret = 0;
2025 dsn_envid = NULL;
2026 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2027 #ifndef DISABLE_PRDR
2028 prdr_requested = FALSE;
2029 #endif
2030 #ifdef EXPERIMENTAL_SPF
2031 spf_header_comment = NULL;
2032 spf_received = NULL;
2033 spf_result = NULL;
2034 spf_smtp_comment = NULL;
2035 #endif
2036 #ifdef SUPPORT_I18N
2037 message_smtputf8 = FALSE;
2038 #endif
2039 body_linecount = body_zerocount = 0;
2040
2041 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2042 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2043 /* Note that ratelimiters_conn persists across resets. */
2044
2045 /* Reset message ACL variables */
2046
2047 acl_var_m = NULL;
2048
2049 /* The message body variables use malloc store. They may be set if this is
2050 not the first message in an SMTP session and the previous message caused them
2051 to be referenced in an ACL. */
2052
2053 if (message_body)
2054 {
2055 store_free(message_body);
2056 message_body = NULL;
2057 }
2058
2059 if (message_body_end)
2060 {
2061 store_free(message_body_end);
2062 message_body_end = NULL;
2063 }
2064
2065 /* Warning log messages are also saved in malloc store. They are saved to avoid
2066 repetition in the same message, but it seems right to repeat them for different
2067 messages. */
2068
2069 while (acl_warn_logged)
2070 {
2071 string_item *this = acl_warn_logged;
2072 acl_warn_logged = acl_warn_logged->next;
2073 store_free(this);
2074 }
2075 store_reset(reset_point);
2076 }
2077
2078
2079
2080
2081
2082 /*************************************************
2083 * Initialize for incoming batched SMTP message *
2084 *************************************************/
2085
2086 /* This function is called from smtp_setup_msg() in the case when
2087 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2088 of messages in one file with SMTP commands between them. All errors must be
2089 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2090 relevant. After an error on a sender, or an invalid recipient, the remainder
2091 of the message is skipped. The value of received_protocol is already set.
2092
2093 Argument: none
2094 Returns: > 0 message successfully started (reached DATA)
2095 = 0 QUIT read or end of file reached
2096 < 0 should not occur
2097 */
2098
2099 static int
2100 smtp_setup_batch_msg(void)
2101 {
2102 int done = 0;
2103 void *reset_point = store_get(0);
2104
2105 /* Save the line count at the start of each transaction - single commands
2106 like HELO and RSET count as whole transactions. */
2107
2108 bsmtp_transaction_linecount = receive_linecount;
2109
2110 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2111
2112 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2113 smtp_reset(reset_point); /* Reset for start of message */
2114
2115 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2116 value. The values are 2 larger than the required yield of the function. */
2117
2118 while (done <= 0)
2119 {
2120 uschar *errmess;
2121 uschar *recipient = NULL;
2122 int start, end, sender_domain, recipient_domain;
2123
2124 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2125 {
2126 /* The HELO/EHLO commands set sender_address_helo if they have
2127 valid data; otherwise they are ignored, except that they do
2128 a reset of the state. */
2129
2130 case HELO_CMD:
2131 case EHLO_CMD:
2132
2133 check_helo(smtp_cmd_data);
2134 /* Fall through */
2135
2136 case RSET_CMD:
2137 cancel_cutthrough_connection(TRUE, US"RSET received");
2138 smtp_reset(reset_point);
2139 bsmtp_transaction_linecount = receive_linecount;
2140 break;
2141
2142
2143 /* The MAIL FROM command requires an address as an operand. All we
2144 do here is to parse it for syntactic correctness. The form "<>" is
2145 a special case which converts into an empty string. The start/end
2146 pointers in the original are not used further for this address, as
2147 it is the canonical extracted address which is all that is kept. */
2148
2149 case MAIL_CMD:
2150 smtp_mailcmd_count++; /* Count for no-mail log */
2151 if (sender_address != NULL)
2152 /* The function moan_smtp_batch() does not return. */
2153 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2154
2155 if (smtp_cmd_data[0] == 0)
2156 /* The function moan_smtp_batch() does not return. */
2157 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2158
2159 /* Reset to start of message */
2160
2161 cancel_cutthrough_connection(TRUE, US"MAIL received");
2162 smtp_reset(reset_point);
2163
2164 /* Apply SMTP rewrite */
2165
2166 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2167 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2168 US"", global_rewrite_rules) : smtp_cmd_data;
2169
2170 /* Extract the address; the TRUE flag allows <> as valid */
2171
2172 raw_sender =
2173 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2174 TRUE);
2175
2176 if (raw_sender == NULL)
2177 /* The function moan_smtp_batch() does not return. */
2178 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2179
2180 sender_address = string_copy(raw_sender);
2181
2182 /* Qualify unqualified sender addresses if permitted to do so. */
2183
2184 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
2185 {
2186 if (allow_unqualified_sender)
2187 {
2188 sender_address = rewrite_address_qualify(sender_address, FALSE);
2189 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2190 "and rewritten\n", raw_sender);
2191 }
2192 /* The function moan_smtp_batch() does not return. */
2193 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2194 "a domain");
2195 }
2196 break;
2197
2198
2199 /* The RCPT TO command requires an address as an operand. All we do
2200 here is to parse it for syntactic correctness. There may be any number
2201 of RCPT TO commands, specifying multiple senders. We build them all into
2202 a data structure that is in argc/argv format. The start/end values
2203 given by parse_extract_address are not used, as we keep only the
2204 extracted address. */
2205
2206 case RCPT_CMD:
2207 if (sender_address == NULL)
2208 /* The function moan_smtp_batch() does not return. */
2209 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2210
2211 if (smtp_cmd_data[0] == 0)
2212 /* The function moan_smtp_batch() does not return. */
2213 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
2214
2215 /* Check maximum number allowed */
2216
2217 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2218 /* The function moan_smtp_batch() does not return. */
2219 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2220 recipients_max_reject? "552": "452");
2221
2222 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2223 recipient address */
2224
2225 recipient = rewrite_existflags & rewrite_smtp
2226 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2227 global_rewrite_rules)
2228 : smtp_cmd_data;
2229
2230 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2231 &recipient_domain, FALSE);
2232
2233 if (!recipient)
2234 /* The function moan_smtp_batch() does not return. */
2235 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2236
2237 /* If the recipient address is unqualified, qualify it if permitted. Then
2238 add it to the list of recipients. */
2239
2240 if (recipient_domain == 0)
2241 {
2242 if (allow_unqualified_recipient)
2243 {
2244 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2245 recipient);
2246 recipient = rewrite_address_qualify(recipient, TRUE);
2247 }
2248 /* The function moan_smtp_batch() does not return. */
2249 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
2250 "a domain");
2251 }
2252 receive_add_recipient(recipient, -1);
2253 break;
2254
2255
2256 /* The DATA command is legal only if it follows successful MAIL FROM
2257 and RCPT TO commands. This function is complete when a valid DATA
2258 command is encountered. */
2259
2260 case DATA_CMD:
2261 if (sender_address == NULL || recipients_count <= 0)
2262 {
2263 /* The function moan_smtp_batch() does not return. */
2264 if (sender_address == NULL)
2265 moan_smtp_batch(smtp_cmd_buffer,
2266 "503 MAIL FROM:<sender> command must precede DATA");
2267 else
2268 moan_smtp_batch(smtp_cmd_buffer,
2269 "503 RCPT TO:<recipient> must precede DATA");
2270 }
2271 else
2272 {
2273 done = 3; /* DATA successfully achieved */
2274 message_ended = END_NOTENDED; /* Indicate in middle of message */
2275 }
2276 break;
2277
2278
2279 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2280
2281 case VRFY_CMD:
2282 case EXPN_CMD:
2283 case HELP_CMD:
2284 case NOOP_CMD:
2285 case ETRN_CMD:
2286 bsmtp_transaction_linecount = receive_linecount;
2287 break;
2288
2289
2290 case EOF_CMD:
2291 case QUIT_CMD:
2292 done = 2;
2293 break;
2294
2295
2296 case BADARG_CMD:
2297 /* The function moan_smtp_batch() does not return. */
2298 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2299 break;
2300
2301
2302 case BADCHAR_CMD:
2303 /* The function moan_smtp_batch() does not return. */
2304 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2305 break;
2306
2307
2308 default:
2309 /* The function moan_smtp_batch() does not return. */
2310 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2311 break;
2312 }
2313 }
2314
2315 return done - 2; /* Convert yield values */
2316 }
2317
2318
2319
2320
2321 static BOOL
2322 smtp_log_tls_fail(uschar * errstr)
2323 {
2324 uschar * conn_info = smtp_get_connection_info();
2325
2326 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2327 /* I'd like to get separated H= here, but too hard for now */
2328
2329 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2330 return FALSE;
2331 }
2332
2333
2334 /*************************************************
2335 * Start an SMTP session *
2336 *************************************************/
2337
2338 /* This function is called at the start of an SMTP session. Thereafter,
2339 smtp_setup_msg() is called to initiate each separate message. This
2340 function does host-specific testing, and outputs the banner line.
2341
2342 Arguments: none
2343 Returns: FALSE if the session can not continue; something has
2344 gone wrong, or the connection to the host is blocked
2345 */
2346
2347 BOOL
2348 smtp_start_session(void)
2349 {
2350 int size = 256;
2351 int ptr, esclen;
2352 uschar *user_msg, *log_msg;
2353 uschar *code, *esc;
2354 uschar *p, *s, *ss;
2355
2356 smtp_connection_start = time(NULL);
2357 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2358 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2359 smtp_ch_index = 0;
2360
2361 /* Default values for certain variables */
2362
2363 helo_seen = esmtp = helo_accept_junk = FALSE;
2364 smtp_mailcmd_count = 0;
2365 count_nonmail = TRUE_UNSET;
2366 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2367 smtp_delay_mail = smtp_rlm_base;
2368 auth_advertised = FALSE;
2369 pipelining_advertised = FALSE;
2370 pipelining_enable = TRUE;
2371 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2372 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2373
2374 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2375 authentication settings from -oMaa to remain in force. */
2376
2377 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2378 authenticated_by = NULL;
2379
2380 #ifdef SUPPORT_TLS
2381 tls_in.cipher = tls_in.peerdn = NULL;
2382 tls_in.ourcert = tls_in.peercert = NULL;
2383 tls_in.sni = NULL;
2384 tls_in.ocsp = OCSP_NOT_REQ;
2385 tls_advertised = FALSE;
2386 #endif
2387 dsn_advertised = FALSE;
2388 #ifdef SUPPORT_I18N
2389 smtputf8_advertised = FALSE;
2390 #endif
2391
2392 /* Reset ACL connection variables */
2393
2394 acl_var_c = NULL;
2395
2396 /* Allow for trailing 0 in the command and data buffers. */
2397
2398 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2399 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2400 "malloc() failed for SMTP command buffer");
2401
2402 smtp_cmd_buffer[0] = 0;
2403 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2404
2405 /* For batched input, the protocol setting can be overridden from the
2406 command line by a trusted caller. */
2407
2408 if (smtp_batched_input)
2409 {
2410 if (!received_protocol) received_protocol = US"local-bsmtp";
2411 }
2412
2413 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2414 reset later if any of EHLO/AUTH/STARTTLS are received. */
2415
2416 else
2417 received_protocol =
2418 (sender_host_address ? protocols : protocols_local) [pnormal];
2419
2420 /* Set up the buffer for inputting using direct read() calls, and arrange to
2421 call the local functions instead of the standard C ones. */
2422
2423 if (!(smtp_inbuffer = (uschar *)malloc(IN_BUFFER_SIZE)))
2424 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2425
2426 receive_getc = smtp_getc;
2427 receive_getbuf = smtp_getbuf;
2428 receive_get_cache = smtp_get_cache;
2429 receive_ungetc = smtp_ungetc;
2430 receive_feof = smtp_feof;
2431 receive_ferror = smtp_ferror;
2432 receive_smtp_buffered = smtp_buffered;
2433 smtp_inptr = smtp_inend = smtp_inbuffer;
2434 smtp_had_eof = smtp_had_error = 0;
2435
2436 /* Set up the message size limit; this may be host-specific */
2437
2438 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2439 if (expand_string_message != NULL)
2440 {
2441 if (thismessage_size_limit == -1)
2442 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2443 "%s", expand_string_message);
2444 else
2445 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2446 "%s", expand_string_message);
2447 smtp_closedown(US"Temporary local problem - please try later");
2448 return FALSE;
2449 }
2450
2451 /* When a message is input locally via the -bs or -bS options, sender_host_
2452 unknown is set unless -oMa was used to force an IP address, in which case it
2453 is checked like a real remote connection. When -bs is used from inetd, this
2454 flag is not set, causing the sending host to be checked. The code that deals
2455 with IP source routing (if configured) is never required for -bs or -bS and
2456 the flag sender_host_notsocket is used to suppress it.
2457
2458 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2459 reserve for certain hosts and/or networks. */
2460
2461 if (!sender_host_unknown)
2462 {
2463 int rc;
2464 BOOL reserved_host = FALSE;
2465
2466 /* Look up IP options (source routing info) on the socket if this is not an
2467 -oMa "host", and if any are found, log them and drop the connection.
2468
2469 Linux (and others now, see below) is different to everyone else, so there
2470 has to be some conditional compilation here. Versions of Linux before 2.1.15
2471 used a structure whose name was "options". Somebody finally realized that
2472 this name was silly, and it got changed to "ip_options". I use the
2473 newer name here, but there is a fudge in the script that sets up os.h
2474 to define a macro in older Linux systems.
2475
2476 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2477 glibc 2, which has chosen ip_opts for the structure name. This is now
2478 really a glibc thing rather than a Linux thing, so the condition name
2479 has been changed to reflect this. It is relevant also to GNU/Hurd.
2480
2481 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2482 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2483 a special macro defined in the os.h file.
2484
2485 Some DGUX versions on older hardware appear not to support IP options at
2486 all, so there is now a general macro which can be set to cut out this
2487 support altogether.
2488
2489 How to do this properly in IPv6 is not yet known. */
2490
2491 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2492
2493 #ifdef GLIBC_IP_OPTIONS
2494 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2495 #define OPTSTYLE 1
2496 #else
2497 #define OPTSTYLE 2
2498 #endif
2499 #elif defined DARWIN_IP_OPTIONS
2500 #define OPTSTYLE 2
2501 #else
2502 #define OPTSTYLE 3
2503 #endif
2504
2505 if (!host_checking && !sender_host_notsocket)
2506 {
2507 #if OPTSTYLE == 1
2508 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2509 struct ip_options *ipopt = store_get(optlen);
2510 #elif OPTSTYLE == 2
2511 struct ip_opts ipoptblock;
2512 struct ip_opts *ipopt = &ipoptblock;
2513 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2514 #else
2515 struct ipoption ipoptblock;
2516 struct ipoption *ipopt = &ipoptblock;
2517 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2518 #endif
2519
2520 /* Occasional genuine failures of getsockopt() have been seen - for
2521 example, "reset by peer". Therefore, just log and give up on this
2522 call, unless the error is ENOPROTOOPT. This error is given by systems
2523 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2524 of writing. So for that error, carry on - we just can't do an IP options
2525 check. */
2526
2527 DEBUG(D_receive) debug_printf("checking for IP options\n");
2528
2529 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2530 &optlen) < 0)
2531 {
2532 if (errno != ENOPROTOOPT)
2533 {
2534 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2535 host_and_ident(FALSE), strerror(errno));
2536 smtp_printf("451 SMTP service not available\r\n", FALSE);
2537 return FALSE;
2538 }
2539 }
2540
2541 /* Deal with any IP options that are set. On the systems I have looked at,
2542 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2543 more logging data than will fit in big_buffer. Nevertheless, after somebody
2544 questioned this code, I've added in some paranoid checking. */
2545
2546 else if (optlen > 0)
2547 {
2548 uschar *p = big_buffer;
2549 uschar *pend = big_buffer + big_buffer_size;
2550 uschar *opt, *adptr;
2551 int optcount;
2552 struct in_addr addr;
2553
2554 #if OPTSTYLE == 1
2555 uschar *optstart = (uschar *)(ipopt->__data);
2556 #elif OPTSTYLE == 2
2557 uschar *optstart = (uschar *)(ipopt->ip_opts);
2558 #else
2559 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2560 #endif
2561
2562 DEBUG(D_receive) debug_printf("IP options exist\n");
2563
2564 Ustrcpy(p, "IP options on incoming call:");
2565 p += Ustrlen(p);
2566
2567 for (opt = optstart; opt != NULL &&
2568 opt < (uschar *)(ipopt) + optlen;)
2569 {
2570 switch (*opt)
2571 {
2572 case IPOPT_EOL:
2573 opt = NULL;
2574 break;
2575
2576 case IPOPT_NOP:
2577 opt++;
2578 break;
2579
2580 case IPOPT_SSRR:
2581 case IPOPT_LSRR:
2582 if (!string_format(p, pend-p, " %s [@%s",
2583 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2584 #if OPTSTYLE == 1
2585 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2586 #elif OPTSTYLE == 2
2587 inet_ntoa(ipopt->ip_dst)))
2588 #else
2589 inet_ntoa(ipopt->ipopt_dst)))
2590 #endif
2591 {
2592 opt = NULL;
2593 break;
2594 }
2595
2596 p += Ustrlen(p);
2597 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2598 adptr = opt + 3;
2599 while (optcount-- > 0)
2600 {
2601 memcpy(&addr, adptr, sizeof(addr));
2602 if (!string_format(p, pend - p - 1, "%s%s",
2603 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2604 {
2605 opt = NULL;
2606 break;
2607 }
2608 p += Ustrlen(p);
2609 adptr += sizeof(struct in_addr);
2610 }
2611 *p++ = ']';
2612 opt += opt[1];
2613 break;
2614
2615 default:
2616 {
2617 int i;
2618 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2619 Ustrcat(p, "[ ");
2620 p += 2;
2621 for (i = 0; i < opt[1]; i++)
2622 {
2623 sprintf(CS p, "%2.2x ", opt[i]);
2624 p += 3;
2625 }
2626 *p++ = ']';
2627 }
2628 opt += opt[1];
2629 break;
2630 }
2631 }
2632
2633 *p = 0;
2634 log_write(0, LOG_MAIN, "%s", big_buffer);
2635
2636 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2637
2638 log_write(0, LOG_MAIN|LOG_REJECT,
2639 "connection from %s refused (IP options)", host_and_ident(FALSE));
2640
2641 smtp_printf("554 SMTP service not available\r\n", FALSE);
2642 return FALSE;
2643 }
2644
2645 /* Length of options = 0 => there are no options */
2646
2647 else DEBUG(D_receive) debug_printf("no IP options found\n");
2648 }
2649 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2650
2651 /* Set keep-alive in socket options. The option is on by default. This
2652 setting is an attempt to get rid of some hanging connections that stick in
2653 read() when the remote end (usually a dialup) goes away. */
2654
2655 if (smtp_accept_keepalive && !sender_host_notsocket)
2656 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2657
2658 /* If the current host matches host_lookup, set the name by doing a
2659 reverse lookup. On failure, sender_host_name will be NULL and
2660 host_lookup_failed will be TRUE. This may or may not be serious - optional
2661 checks later. */
2662
2663 if (verify_check_host(&host_lookup) == OK)
2664 {
2665 (void)host_name_lookup();
2666 host_build_sender_fullhost();
2667 }
2668
2669 /* Delay this until we have the full name, if it is looked up. */
2670
2671 set_process_info("handling incoming connection from %s",
2672 host_and_ident(FALSE));
2673
2674 /* Expand smtp_receive_timeout, if needed */
2675
2676 if (smtp_receive_timeout_s)
2677 {
2678 uschar * exp;
2679 if ( !(exp = expand_string(smtp_receive_timeout_s))
2680 || !(*exp)
2681 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2682 )
2683 log_write(0, LOG_MAIN|LOG_PANIC,
2684 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2685 }
2686
2687 /* Test for explicit connection rejection */
2688
2689 if (verify_check_host(&host_reject_connection) == OK)
2690 {
2691 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2692 "from %s (host_reject_connection)", host_and_ident(FALSE));
2693 smtp_printf("554 SMTP service not available\r\n", FALSE);
2694 return FALSE;
2695 }
2696
2697 /* Test with TCP Wrappers if so configured. There is a problem in that
2698 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2699 such as disks dying. In these cases, it is desirable to reject with a 4xx
2700 error instead of a 5xx error. There isn't a "right" way to detect such
2701 problems. The following kludge is used: errno is zeroed before calling
2702 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2703 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2704 not exist). */
2705
2706 #ifdef USE_TCP_WRAPPERS
2707 errno = 0;
2708 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2709 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2710 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2711 expand_string_message);
2712
2713 if (!hosts_ctl(tcp_wrappers_name,
2714 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2715 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2716 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2717 {
2718 if (errno == 0 || errno == ENOENT)
2719 {
2720 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2721 log_write(L_connection_reject,
2722 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2723 "(tcp wrappers)", host_and_ident(FALSE));
2724 smtp_printf("554 SMTP service not available\r\n", FALSE);
2725 }
2726 else
2727 {
2728 int save_errno = errno;
2729 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2730 "errno value %d\n", save_errno);
2731 log_write(L_connection_reject,
2732 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2733 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2734 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2735 }
2736 return FALSE;
2737 }
2738 #endif
2739
2740 /* Check for reserved slots. The value of smtp_accept_count has already been
2741 incremented to include this process. */
2742
2743 if (smtp_accept_max > 0 &&
2744 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2745 {
2746 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2747 {
2748 log_write(L_connection_reject,
2749 LOG_MAIN, "temporarily refused connection from %s: not in "
2750 "reserve list: connected=%d max=%d reserve=%d%s",
2751 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2752 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2753 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2754 "please try again later\r\n", FALSE, smtp_active_hostname);
2755 return FALSE;
2756 }
2757 reserved_host = TRUE;
2758 }
2759
2760 /* If a load level above which only messages from reserved hosts are
2761 accepted is set, check the load. For incoming calls via the daemon, the
2762 check is done in the superior process if there are no reserved hosts, to
2763 save a fork. In all cases, the load average will already be available
2764 in a global variable at this point. */
2765
2766 if (smtp_load_reserve >= 0 &&
2767 load_average > smtp_load_reserve &&
2768 !reserved_host &&
2769 verify_check_host(&smtp_reserve_hosts) != OK)
2770 {
2771 log_write(L_connection_reject,
2772 LOG_MAIN, "temporarily refused connection from %s: not in "
2773 "reserve list and load average = %.2f", host_and_ident(FALSE),
2774 (double)load_average/1000.0);
2775 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2776 smtp_active_hostname);
2777 return FALSE;
2778 }
2779
2780 /* Determine whether unqualified senders or recipients are permitted
2781 for this host. Unfortunately, we have to do this every time, in order to
2782 set the flags so that they can be inspected when considering qualifying
2783 addresses in the headers. For a site that permits no qualification, this
2784 won't take long, however. */
2785
2786 allow_unqualified_sender =
2787 verify_check_host(&sender_unqualified_hosts) == OK;
2788
2789 allow_unqualified_recipient =
2790 verify_check_host(&recipient_unqualified_hosts) == OK;
2791
2792 /* Determine whether HELO/EHLO is required for this host. The requirement
2793 can be hard or soft. */
2794
2795 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2796 if (!helo_required)
2797 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2798
2799 /* Determine whether this hosts is permitted to send syntactic junk
2800 after a HELO or EHLO command. */
2801
2802 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2803 }
2804
2805 /* For batch SMTP input we are now done. */
2806
2807 if (smtp_batched_input) return TRUE;
2808
2809 /* If valid Proxy Protocol source is connecting, set up session.
2810 * Failure will not allow any SMTP function other than QUIT. */
2811
2812 #ifdef SUPPORT_PROXY
2813 proxy_session = FALSE;
2814 proxy_session_failed = FALSE;
2815 if (check_proxy_protocol_host())
2816 setup_proxy_protocol_host();
2817 #endif
2818
2819 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2820 smtps port for use with older style SSL MTAs. */
2821
2822 #ifdef SUPPORT_TLS
2823 if (tls_in.on_connect && tls_server_start(tls_require_ciphers, &user_msg) != OK)
2824 return smtp_log_tls_fail(user_msg);
2825 #endif
2826
2827 /* Run the connect ACL if it exists */
2828
2829 user_msg = NULL;
2830 if (acl_smtp_connect)
2831 {
2832 int rc;
2833 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2834 &log_msg)) != OK)
2835 {
2836 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2837 return FALSE;
2838 }
2839 }
2840
2841 /* Output the initial message for a two-way SMTP connection. It may contain
2842 newlines, which then cause a multi-line response to be given. */
2843
2844 code = US"220"; /* Default status code */
2845 esc = US""; /* Default extended status code */
2846 esclen = 0; /* Length of esc */
2847
2848 if (!user_msg)
2849 {
2850 if (!(s = expand_string(smtp_banner)))
2851 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2852 "failed: %s", smtp_banner, expand_string_message);
2853 }
2854 else
2855 {
2856 int codelen = 3;
2857 s = user_msg;
2858 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2859 if (codelen > 4)
2860 {
2861 esc = code + 4;
2862 esclen = codelen - 4;
2863 }
2864 }
2865
2866 /* Remove any terminating newlines; might as well remove trailing space too */
2867
2868 p = s + Ustrlen(s);
2869 while (p > s && isspace(p[-1])) p--;
2870 *p = 0;
2871
2872 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2873 is all contained in a single IP packet. The original code wrote out the
2874 greeting using several calls to fprint/fputc, and on busy servers this could
2875 cause it to be split over more than one packet - which caused CC:Mail to fall
2876 over when it got the second part of the greeting after sending its first
2877 command. Sigh. To try to avoid this, build the complete greeting message
2878 first, and output it in one fell swoop. This gives a better chance of it
2879 ending up as a single packet. */
2880
2881 ss = store_get(size);
2882 ptr = 0;
2883
2884 p = s;
2885 do /* At least once, in case we have an empty string */
2886 {
2887 int len;
2888 uschar *linebreak = Ustrchr(p, '\n');
2889 ss = string_catn(ss, &size, &ptr, code, 3);
2890 if (linebreak == NULL)
2891 {
2892 len = Ustrlen(p);
2893 ss = string_catn(ss, &size, &ptr, US" ", 1);
2894 }
2895 else
2896 {
2897 len = linebreak - p;
2898 ss = string_catn(ss, &size, &ptr, US"-", 1);
2899 }
2900 ss = string_catn(ss, &size, &ptr, esc, esclen);
2901 ss = string_catn(ss, &size, &ptr, p, len);
2902 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2903 p += len;
2904 if (linebreak != NULL) p++;
2905 }
2906 while (*p != 0);
2907
2908 ss[ptr] = 0; /* string_cat leaves room for this */
2909
2910 /* Before we write the banner, check that there is no input pending, unless
2911 this synchronisation check is disabled. */
2912
2913 if (!check_sync())
2914 {
2915 unsigned n = smtp_inend - smtp_inptr;
2916 if (n > 32) n = 32;
2917
2918 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2919 "synchronization error (input sent without waiting for greeting): "
2920 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2921 string_printing(string_copyn(smtp_inptr, n)));
2922 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2923 return FALSE;
2924 }
2925
2926 /* Now output the banner */
2927
2928 smtp_printf("%s", FALSE, ss);
2929 return TRUE;
2930 }
2931
2932
2933
2934
2935
2936 /*************************************************
2937 * Handle SMTP syntax and protocol errors *
2938 *************************************************/
2939
2940 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2941 to do so. Then transmit the error response. The return value depends on the
2942 number of syntax and protocol errors in this SMTP session.
2943
2944 Arguments:
2945 type error type, given as a log flag bit
2946 code response code; <= 0 means don't send a response
2947 data data to reflect in the response (can be NULL)
2948 errmess the error message
2949
2950 Returns: -1 limit of syntax/protocol errors NOT exceeded
2951 +1 limit of syntax/protocol errors IS exceeded
2952
2953 These values fit in with the values of the "done" variable in the main
2954 processing loop in smtp_setup_msg(). */
2955
2956 static int
2957 synprot_error(int type, int code, uschar *data, uschar *errmess)
2958 {
2959 int yield = -1;
2960
2961 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2962 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2963 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2964
2965 if (++synprot_error_count > smtp_max_synprot_errors)
2966 {
2967 yield = 1;
2968 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2969 "syntax or protocol errors (last command was \"%s\")",
2970 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2971 }
2972
2973 if (code > 0)
2974 {
2975 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
2976 data ? data : US"", data ? US": " : US"", errmess);
2977 if (yield == 1)
2978 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
2979 }
2980
2981 return yield;
2982 }
2983
2984
2985
2986
2987 /*************************************************
2988 * Send SMTP response, possibly multiline *
2989 *************************************************/
2990
2991 /* There are, it seems, broken clients out there that cannot handle multiline
2992 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2993 output nothing for non-final calls, and only the first line for anything else.
2994
2995 Arguments:
2996 code SMTP code, may involve extended status codes
2997 codelen length of smtp code; if > 4 there's an ESC
2998 final FALSE if the last line isn't the final line
2999 msg message text, possibly containing newlines
3000
3001 Returns: nothing
3002 */
3003
3004 void
3005 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3006 {
3007 int esclen = 0;
3008 uschar *esc = US"";
3009
3010 if (!final && no_multiline_responses) return;
3011
3012 if (codelen > 4)
3013 {
3014 esc = code + 4;
3015 esclen = codelen - 4;
3016 }
3017
3018 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3019 have had the same. Note: this code is also present in smtp_printf(). It would
3020 be tidier to have it only in one place, but when it was added, it was easier to
3021 do it that way, so as not to have to mess with the code for the RCPT command,
3022 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3023
3024 if (rcpt_in_progress)
3025 {
3026 if (rcpt_smtp_response == NULL)
3027 rcpt_smtp_response = string_copy(msg);
3028 else if (rcpt_smtp_response_same &&
3029 Ustrcmp(rcpt_smtp_response, msg) != 0)
3030 rcpt_smtp_response_same = FALSE;
3031 rcpt_in_progress = FALSE;
3032 }
3033
3034 /* Now output the message, splitting it up into multiple lines if necessary.
3035 We only handle pipelining these responses as far as nonfinal/final groups,
3036 not the whole MAIL/RCPT/DATA response set. */
3037
3038 for (;;)
3039 {
3040 uschar *nl = Ustrchr(msg, '\n');
3041 if (nl == NULL)
3042 {
3043 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3044 return;
3045 }
3046 else if (nl[1] == 0 || no_multiline_responses)
3047 {
3048 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3049 (int)(nl - msg), msg);
3050 return;
3051 }
3052 else
3053 {
3054 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3055 msg = nl + 1;
3056 while (isspace(*msg)) msg++;
3057 }
3058 }
3059 }
3060
3061
3062
3063
3064 /*************************************************
3065 * Parse user SMTP message *
3066 *************************************************/
3067
3068 /* This function allows for user messages overriding the response code details
3069 by providing a suitable response code string at the start of the message
3070 user_msg. Check the message for starting with a response code and optionally an
3071 extended status code. If found, check that the first digit is valid, and if so,
3072 change the code pointer and length to use the replacement. An invalid code
3073 causes a panic log; in this case, if the log messages is the same as the user
3074 message, we must also adjust the value of the log message to show the code that
3075 is actually going to be used (the original one).
3076
3077 This function is global because it is called from receive.c as well as within
3078 this module.
3079
3080 Note that the code length returned includes the terminating whitespace
3081 character, which is always included in the regex match.
3082
3083 Arguments:
3084 code SMTP code, may involve extended status codes
3085 codelen length of smtp code; if > 4 there's an ESC
3086 msg message text
3087 log_msg optional log message, to be adjusted with the new SMTP code
3088 check_valid if true, verify the response code
3089
3090 Returns: nothing
3091 */
3092
3093 void
3094 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3095 BOOL check_valid)
3096 {
3097 int n;
3098 int ovector[3];
3099
3100 if (!msg || !*msg) return;
3101
3102 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3103 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3104
3105 if (check_valid && (*msg)[0] != (*code)[0])
3106 {
3107 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3108 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3109 if (log_msg != NULL && *log_msg == *msg)
3110 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3111 }
3112 else
3113 {
3114 *code = *msg;
3115 *codelen = ovector[1]; /* Includes final space */
3116 }
3117 *msg += ovector[1]; /* Chop the code off the message */
3118 return;
3119 }
3120
3121
3122
3123
3124 /*************************************************
3125 * Handle an ACL failure *
3126 *************************************************/
3127
3128 /* This function is called when acl_check() fails. As well as calls from within
3129 this module, it is called from receive.c for an ACL after DATA. It sorts out
3130 logging the incident, and sets up the error response. A message containing
3131 newlines is turned into a multiline SMTP response, but for logging, only the
3132 first line is used.
3133
3134 There's a table of default permanent failure response codes to use in
3135 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3136 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3137 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3138 state, because there are broken clients that try VRFY before RCPT. A 5xx
3139 response should be given only when the address is positively known to be
3140 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3141 no explicit code, but if there is one we let it know best.
3142 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3143
3144 From Exim 4.63, it is possible to override the response code details by
3145 providing a suitable response code string at the start of the message provided
3146 in user_msg. The code's first digit is checked for validity.
3147
3148 Arguments:
3149 where where the ACL was called from
3150 rc the failure code
3151 user_msg a message that can be included in an SMTP response
3152 log_msg a message for logging
3153
3154 Returns: 0 in most cases
3155 2 if the failure code was FAIL_DROP, in which case the
3156 SMTP connection should be dropped (this value fits with the
3157 "done" variable in smtp_setup_msg() below)
3158 */
3159
3160 int
3161 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3162 {
3163 BOOL drop = rc == FAIL_DROP;
3164 int codelen = 3;
3165 uschar *smtp_code;
3166 uschar *lognl;
3167 uschar *sender_info = US"";
3168 uschar *what =
3169 #ifdef WITH_CONTENT_SCAN
3170 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3171 #endif
3172 where == ACL_WHERE_PREDATA ? US"DATA" :
3173 where == ACL_WHERE_DATA ? US"after DATA" :
3174 #ifndef DISABLE_PRDR
3175 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3176 #endif
3177 smtp_cmd_data ?
3178 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3179 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3180
3181 if (drop) rc = FAIL;
3182
3183 /* Set the default SMTP code, and allow a user message to change it. */
3184
3185 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3186 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3187 where != ACL_WHERE_VRFY);
3188
3189 /* We used to have sender_address here; however, there was a bug that was not
3190 updating sender_address after a rewrite during a verify. When this bug was
3191 fixed, sender_address at this point became the rewritten address. I'm not sure
3192 this is what should be logged, so I've changed to logging the unrewritten
3193 address to retain backward compatibility. */
3194
3195 #ifndef WITH_CONTENT_SCAN
3196 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3197 #else
3198 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3199 #endif
3200 {
3201 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3202 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3203 sender_host_authenticated ? US" A=" : US"",
3204 sender_host_authenticated ? sender_host_authenticated : US"",
3205 sender_host_authenticated && authenticated_id ? US":" : US"",
3206 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3207 );
3208 }
3209
3210 /* If there's been a sender verification failure with a specific message, and
3211 we have not sent a response about it yet, do so now, as a preliminary line for
3212 failures, but not defers. However, always log it for defer, and log it for fail
3213 unless the sender_verify_fail log selector has been turned off. */
3214
3215 if (sender_verified_failed &&
3216 !testflag(sender_verified_failed, af_sverify_told))
3217 {
3218 BOOL save_rcpt_in_progress = rcpt_in_progress;
3219 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3220
3221 setflag(sender_verified_failed, af_sverify_told);
3222
3223 if (rc != FAIL || LOGGING(sender_verify_fail))
3224 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3225 host_and_ident(TRUE),
3226 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3227 sender_verified_failed->address,
3228 (sender_verified_failed->message == NULL)? US"" :
3229 string_sprintf(": %s", sender_verified_failed->message));
3230
3231 if (rc == FAIL && sender_verified_failed->user_message)
3232 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3233 testflag(sender_verified_failed, af_verify_pmfail)?
3234 "Postmaster verification failed while checking <%s>\n%s\n"
3235 "Several RFCs state that you are required to have a postmaster\n"
3236 "mailbox for each mail domain. This host does not accept mail\n"
3237 "from domains whose servers reject the postmaster address."
3238 :
3239 testflag(sender_verified_failed, af_verify_nsfail)?
3240 "Callback setup failed while verifying <%s>\n%s\n"
3241 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3242 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3243 "RFC requirements, and stops you from receiving standard bounce\n"
3244 "messages. This host does not accept mail from domains whose servers\n"
3245 "refuse bounces."
3246 :
3247 "Verification failed for <%s>\n%s",
3248 sender_verified_failed->address,
3249 sender_verified_failed->user_message));
3250
3251 rcpt_in_progress = save_rcpt_in_progress;
3252 }
3253
3254 /* Sort out text for logging */
3255
3256 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3257 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3258
3259 /* Send permanent failure response to the command, but the code used isn't
3260 always a 5xx one - see comments at the start of this function. If the original
3261 rc was FAIL_DROP we drop the connection and yield 2. */
3262
3263 if (rc == FAIL)
3264 smtp_respond(smtp_code, codelen, TRUE,
3265 user_msg ? user_msg : US"Administrative prohibition");
3266
3267 /* Send temporary failure response to the command. Don't give any details,
3268 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3269 verb, and for a header verify when smtp_return_error_details is set.
3270
3271 This conditional logic is all somewhat of a mess because of the odd
3272 interactions between temp_details and return_error_details. One day it should
3273 be re-implemented in a tidier fashion. */
3274
3275 else
3276 if (acl_temp_details && user_msg)
3277 {
3278 if ( smtp_return_error_details
3279 && sender_verified_failed
3280 && sender_verified_failed->message
3281 )
3282 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3283
3284 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3285 }
3286 else
3287 smtp_respond(smtp_code, codelen, TRUE,
3288 US"Temporary local problem - please try later");
3289
3290 /* Log the incident to the logs that are specified by log_reject_target
3291 (default main, reject). This can be empty to suppress logging of rejections. If
3292 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3293 is closing if required and return 2. */
3294
3295 if (log_reject_target != 0)
3296 {
3297 #ifdef SUPPORT_TLS
3298 uschar * tls = s_tlslog(NULL, NULL, NULL);
3299 if (!tls) tls = US"";
3300 #else
3301 uschar * tls = US"";
3302 #endif
3303 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3304 log_reject_target, "%s%s%s %s%srejected %s%s",
3305 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3306 host_and_ident(TRUE),
3307 tls,
3308 sender_info,
3309 rc == FAIL ? US"" : US"temporarily ",
3310 what, log_msg);
3311 }
3312
3313 if (!drop) return 0;
3314
3315 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3316 smtp_get_connection_info());
3317
3318 /* Run the not-quit ACL, but without any custom messages. This should not be a
3319 problem, because we get here only if some other ACL has issued "drop", and
3320 in that case, *its* custom messages will have been used above. */
3321
3322 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3323 return 2;
3324 }
3325
3326
3327
3328
3329 /*************************************************
3330 * Handle SMTP exit when QUIT is not given *
3331 *************************************************/
3332
3333 /* This function provides a logging/statistics hook for when an SMTP connection
3334 is dropped on the floor or the other end goes away. It's a global function
3335 because it's called from receive.c as well as this module. As well as running
3336 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3337 response, either with a custom message from the ACL, or using a default. There
3338 is one case, however, when no message is output - after "drop". In that case,
3339 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3340 passed to this function.
3341
3342 In case things go wrong while processing this function, causing an error that
3343 may re-enter this function, there is a recursion check.
3344
3345 Arguments:
3346 reason What $smtp_notquit_reason will be set to in the ACL;
3347 if NULL, the ACL is not run
3348 code The error code to return as part of the response
3349 defaultrespond The default message if there's no user_msg
3350
3351 Returns: Nothing
3352 */
3353
3354 void
3355 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3356 {
3357 int rc;
3358 uschar *user_msg = NULL;
3359 uschar *log_msg = NULL;
3360
3361 /* Check for recursive acll */
3362
3363 if (smtp_exit_function_called)
3364 {
3365 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3366 reason);
3367 return;
3368 }
3369 smtp_exit_function_called = TRUE;
3370
3371 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3372
3373 if (acl_smtp_notquit && reason)
3374 {
3375 smtp_notquit_reason = reason;
3376 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3377 &log_msg)) == ERROR)
3378 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3379 log_msg);
3380 }
3381
3382 /* Write an SMTP response if we are expected to give one. As the default
3383 responses are all internal, they should always fit in the buffer, but code a
3384 warning, just in case. Note that string_vformat() still leaves a complete
3385 string, even if it is incomplete. */
3386
3387 if (code && defaultrespond)
3388 {
3389 if (user_msg)
3390 smtp_respond(code, 3, TRUE, user_msg);
3391 else
3392 {
3393 uschar buffer[128];
3394 va_list ap;
3395 va_start(ap, defaultrespond);
3396 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3397 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3398 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3399 va_end(ap);
3400 }
3401 mac_smtp_fflush();
3402 }
3403 }
3404
3405
3406
3407
3408 /*************************************************
3409 * Verify HELO argument *
3410 *************************************************/
3411
3412 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3413 matched. It is also called from ACL processing if verify = helo is used and
3414 verification was not previously tried (i.e. helo_try_verify_hosts was not
3415 matched). The result of its processing is to set helo_verified and
3416 helo_verify_failed. These variables should both be FALSE for this function to
3417 be called.
3418
3419 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3420 for IPv6 ::ffff: literals.
3421
3422 Argument: none
3423 Returns: TRUE if testing was completed;
3424 FALSE on a temporary failure
3425 */
3426
3427 BOOL
3428 smtp_verify_helo(void)
3429 {
3430 BOOL yield = TRUE;
3431
3432 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3433 sender_helo_name);
3434
3435 if (sender_helo_name == NULL)
3436 {
3437 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3438 }
3439
3440 /* Deal with the case of -bs without an IP address */
3441
3442 else if (sender_host_address == NULL)
3443 {
3444 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3445 helo_verified = TRUE;
3446 }
3447
3448 /* Deal with the more common case when there is a sending IP address */
3449
3450 else if (sender_helo_name[0] == '[')
3451 {
3452 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3453 Ustrlen(sender_host_address)) == 0;
3454
3455 #if HAVE_IPV6
3456 if (!helo_verified)
3457 {
3458 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3459 helo_verified = Ustrncmp(sender_helo_name + 1,
3460 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3461 }
3462 #endif
3463
3464 HDEBUG(D_receive)
3465 { if (helo_verified) debug_printf("matched host address\n"); }
3466 }
3467
3468 /* Do a reverse lookup if one hasn't already given a positive or negative
3469 response. If that fails, or the name doesn't match, try checking with a forward
3470 lookup. */
3471
3472 else
3473 {
3474 if (sender_host_name == NULL && !host_lookup_failed)
3475 yield = host_name_lookup() != DEFER;
3476
3477 /* If a host name is known, check it and all its aliases. */
3478
3479 if (sender_host_name)
3480 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3481 {
3482 sender_helo_dnssec = sender_host_dnssec;
3483 HDEBUG(D_receive) debug_printf("matched host name\n");
3484 }
3485 else
3486 {
3487 uschar **aliases = sender_host_aliases;
3488 while (*aliases)
3489 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3490 {
3491 sender_helo_dnssec = sender_host_dnssec;
3492 break;
3493 }
3494
3495 HDEBUG(D_receive) if (helo_verified)
3496 debug_printf("matched alias %s\n", *(--aliases));
3497 }
3498
3499 /* Final attempt: try a forward lookup of the helo name */
3500
3501 if (!helo_verified)
3502 {
3503 int rc;
3504 host_item h;
3505 dnssec_domains d;
3506 host_item *hh;
3507
3508 h.name = sender_helo_name;
3509 h.address = NULL;
3510 h.mx = MX_NONE;