daaab91724d027b735549466204ce500c7b41177
[exim.git] / src / src / smtp_in.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
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 # ifdef EXPERIMENTAL_REQUIRETLS
139 static BOOL requiretls_advertised;
140 # endif
141 #endif
142 static BOOL dsn_advertised;
143 static BOOL esmtp;
144 static BOOL helo_required = FALSE;
145 static BOOL helo_verify = FALSE;
146 static BOOL helo_seen;
147 static BOOL helo_accept_junk;
148 static BOOL count_nonmail;
149 static BOOL rcpt_smtp_response_same;
150 static BOOL rcpt_in_progress;
151 static int nonmail_command_count;
152 static BOOL smtp_exit_function_called = 0;
153 #ifdef SUPPORT_I18N
154 static BOOL smtputf8_advertised;
155 #endif
156 static int synprot_error_count;
157 static int unknown_command_count;
158 static int sync_cmd_limit;
159 static int smtp_write_error = 0;
160
161 static uschar *rcpt_smtp_response;
162 static uschar *smtp_data_buffer;
163 static uschar *smtp_cmd_data;
164
165 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
166 final fields of all except AUTH are forced TRUE at the start of a new message
167 setup, to allow one of each between messages that is not counted as a nonmail
168 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
169 allow a new EHLO after starting up TLS.
170
171 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
172 counted. However, the flag is changed when AUTH is received, so that multiple
173 failing AUTHs will eventually hit the limit. After a successful AUTH, another
174 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
175 forced TRUE, to allow for the re-authentication that can happen at that point.
176
177 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
178 count of non-mail commands and possibly provoke an error.
179
180 tls_auth is a pseudo-command, never expected in input. It is activated
181 on TLS startup and looks for a tls authenticator. */
182
183 static smtp_cmd_list cmd_list[] = {
184 /* name len cmd has_arg is_mail_cmd */
185
186 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
187 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
188 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
189 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
190 #ifdef SUPPORT_TLS
191 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
192 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
193 #endif
194
195 /* If you change anything above here, also fix the definitions below. */
196
197 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
198 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
199 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
200 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
201 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
202 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
203 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
204 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
205 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
206 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
207 };
208
209 static smtp_cmd_list *cmd_list_end =
210 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
211
212 #define CMD_LIST_RSET 0
213 #define CMD_LIST_HELO 1
214 #define CMD_LIST_EHLO 2
215 #define CMD_LIST_AUTH 3
216 #define CMD_LIST_STARTTLS 4
217 #define CMD_LIST_TLS_AUTH 5
218
219 /* This list of names is used for performing the smtp_no_mail logging action.
220 It must be kept in step with the SCH_xxx enumerations. */
221
222 static uschar *smtp_names[] =
223 {
224 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
225 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
226 US"STARTTLS", US"VRFY" };
227
228 static uschar *protocols_local[] = {
229 US"local-smtp", /* HELO */
230 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
231 US"local-esmtp", /* EHLO */
232 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
233 US"local-esmtpa", /* EHLO->AUTH */
234 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
235 };
236 static uschar *protocols[] = {
237 US"smtp", /* HELO */
238 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
239 US"esmtp", /* EHLO */
240 US"esmtps", /* EHLO->STARTTLS->EHLO */
241 US"esmtpa", /* EHLO->AUTH */
242 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
243 };
244
245 #define pnormal 0
246 #define pextend 2
247 #define pcrpted 1 /* added to pextend or pnormal */
248 #define pauthed 2 /* added to pextend */
249
250 /* Sanity check and validate optional args to MAIL FROM: envelope */
251 enum {
252 ENV_MAIL_OPT_NULL,
253 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
254 #ifndef DISABLE_PRDR
255 ENV_MAIL_OPT_PRDR,
256 #endif
257 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
258 #ifdef SUPPORT_I18N
259 ENV_MAIL_OPT_UTF8,
260 #endif
261 #ifdef EXPERIMENTAL_REQUIRETLS
262 ENV_MAIL_OPT_REQTLS,
263 #endif
264 };
265 typedef struct {
266 uschar * name; /* option requested during MAIL cmd */
267 int value; /* enum type */
268 BOOL need_value; /* TRUE requires value (name=value pair format)
269 FALSE is a singleton */
270 } env_mail_type_t;
271 static env_mail_type_t env_mail_type_list[] = {
272 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
273 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
274 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
275 #ifndef DISABLE_PRDR
276 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
277 #endif
278 { US"RET", ENV_MAIL_OPT_RET, TRUE },
279 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
280 #ifdef SUPPORT_I18N
281 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
282 #endif
283 #ifdef EXPERIMENTAL_REQUIRETLS
284 /* https://tools.ietf.org/html/draft-ietf-uta-smtp-require-tls-03 */
285 { US"REQUIRETLS",ENV_MAIL_OPT_REQTLS, FALSE },
286 #endif
287 /* keep this the last entry */
288 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
289 };
290
291 /* When reading SMTP from a remote host, we have to use our own versions of the
292 C input-reading functions, in order to be able to flush the SMTP output only
293 when about to read more data from the socket. This is the only way to get
294 optimal performance when the client is using pipelining. Flushing for every
295 command causes a separate packet and reply packet each time; saving all the
296 responses up (when pipelining) combines them into one packet and one response.
297
298 For simplicity, these functions are used for *all* SMTP input, not only when
299 receiving over a socket. However, after setting up a secure socket (SSL), input
300 is read via the OpenSSL library, and another set of functions is used instead
301 (see tls.c).
302
303 These functions are set in the receive_getc etc. variables and called with the
304 same interface as the C functions. However, since there can only ever be
305 one incoming SMTP call, we just use a single buffer and flags. There is no need
306 to implement a complicated private FILE-like structure.*/
307
308 static uschar *smtp_inbuffer;
309 static uschar *smtp_inptr;
310 static uschar *smtp_inend;
311 static int smtp_had_eof;
312 static int smtp_had_error;
313
314
315 /* forward declarations */
316 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
317 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
318 static void smtp_quit_handler(uschar **, uschar **);
319 static void smtp_rset_handler(void);
320
321 /*************************************************
322 * Recheck synchronization *
323 *************************************************/
324
325 /* Synchronization checks can never be perfect because a packet may be on its
326 way but not arrived when the check is done. Normally, the checks happen when
327 commands are read: Exim ensures that there is no more input in the input buffer.
328 In normal cases, the response to the command will be fast, and there is no
329 further check.
330
331 However, for some commands an ACL is run, and that can include delays. In those
332 cases, it is useful to do another check on the input just before sending the
333 response. This also applies at the start of a connection. This function does
334 that check by means of the select() function, as long as the facility is not
335 disabled or inappropriate. A failure of select() is ignored.
336
337 When there is unwanted input, we read it so that it appears in the log of the
338 error.
339
340 Arguments: none
341 Returns: TRUE if all is well; FALSE if there is input pending
342 */
343
344 static BOOL
345 wouldblock_reading(void)
346 {
347 int fd, rc;
348 fd_set fds;
349 struct timeval tzero;
350
351 #ifdef SUPPORT_TLS
352 if (tls_in.active.sock >= 0)
353 return !tls_could_read();
354 #endif
355
356 if (smtp_inptr < smtp_inend)
357 return FALSE;
358
359 fd = fileno(smtp_in);
360 FD_ZERO(&fds);
361 FD_SET(fd, &fds);
362 tzero.tv_sec = 0;
363 tzero.tv_usec = 0;
364 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
365
366 if (rc <= 0) return TRUE; /* Not ready to read */
367 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
368 if (rc < 0) return TRUE; /* End of file or error */
369
370 smtp_ungetc(rc);
371 return FALSE;
372 }
373
374 static BOOL
375 check_sync(void)
376 {
377 if (!smtp_enforce_sync || !sender_host_address || sender_host_notsocket)
378 return TRUE;
379
380 return wouldblock_reading();
381 }
382
383
384 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
385 a reponse with the one following. */
386
387 static BOOL
388 pipeline_response(void)
389 {
390 if ( !smtp_enforce_sync || !sender_host_address
391 || sender_host_notsocket || !smtp_in_pipelining_advertised)
392 return FALSE;
393
394 return !wouldblock_reading();
395 }
396
397
398
399 /*************************************************
400 * Log incomplete transactions *
401 *************************************************/
402
403 /* This function is called after a transaction has been aborted by RSET, QUIT,
404 connection drops or other errors. It logs the envelope information received
405 so far in order to preserve address verification attempts.
406
407 Argument: string to indicate what aborted the transaction
408 Returns: nothing
409 */
410
411 static void
412 incomplete_transaction_log(uschar *what)
413 {
414 if (sender_address == NULL || /* No transaction in progress */
415 !LOGGING(smtp_incomplete_transaction))
416 return;
417
418 /* Build list of recipients for logging */
419
420 if (recipients_count > 0)
421 {
422 int i;
423 raw_recipients = store_get(recipients_count * sizeof(uschar *));
424 for (i = 0; i < recipients_count; i++)
425 raw_recipients[i] = recipients_list[i].address;
426 raw_recipients_count = recipients_count;
427 }
428
429 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
430 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
431 }
432
433
434
435
436 void
437 smtp_command_timeout_exit(void)
438 {
439 log_write(L_lost_incoming_connection,
440 LOG_MAIN, "SMTP command timeout on%s connection from %s",
441 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
442 if (smtp_batched_input)
443 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
444 smtp_notquit_exit(US"command-timeout", US"421",
445 US"%s: SMTP command timeout - closing connection",
446 smtp_active_hostname);
447 exim_exit(EXIT_FAILURE, US"receiving");
448 }
449
450 void
451 smtp_command_sigterm_exit(void)
452 {
453 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
454 if (smtp_batched_input)
455 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
456 smtp_notquit_exit(US"signal-exit", US"421",
457 US"%s: Service not available - closing connection", smtp_active_hostname);
458 exim_exit(EXIT_FAILURE, US"receiving");
459 }
460
461 void
462 smtp_data_timeout_exit(void)
463 {
464 log_write(L_lost_incoming_connection,
465 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
466 sender_fullhost ? sender_fullhost : US"local process", sender_address);
467 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
468 /* Does not return */
469 }
470
471 void
472 smtp_data_sigint_exit(void)
473 {
474 log_write(0, LOG_MAIN, "%s closed after %s",
475 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
476 receive_bomb_out(US"signal-exit",
477 US"Service not available - SIGTERM or SIGINT received");
478 /* Does not return */
479 }
480
481
482
483 /* Refill the buffer, and notify DKIM verification code.
484 Return false for error or EOF.
485 */
486
487 static BOOL
488 smtp_refill(unsigned lim)
489 {
490 int rc, save_errno;
491 if (!smtp_out) return FALSE;
492 fflush(smtp_out);
493 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
494
495 /* Limit amount read, so non-message data is not fed to DKIM.
496 Take care to not touch the safety NUL at the end of the buffer. */
497
498 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
499 save_errno = errno;
500 if (smtp_receive_timeout > 0) alarm(0);
501 if (rc <= 0)
502 {
503 /* Must put the error text in fixed store, because this might be during
504 header reading, where it releases unused store above the header. */
505 if (rc < 0)
506 {
507 if (had_command_timeout) /* set by signal handler */
508 smtp_command_timeout_exit(); /* does not return */
509 if (had_command_sigterm)
510 smtp_command_sigterm_exit();
511 if (had_data_timeout)
512 smtp_data_timeout_exit();
513 if (had_data_sigint)
514 smtp_data_sigint_exit();
515
516 smtp_had_error = save_errno;
517 smtp_read_error = string_copy_malloc(
518 string_sprintf(" (error: %s)", strerror(save_errno)));
519 }
520 else
521 smtp_had_eof = 1;
522 return FALSE;
523 }
524 #ifndef DISABLE_DKIM
525 dkim_exim_verify_feed(smtp_inbuffer, rc);
526 #endif
527 smtp_inend = smtp_inbuffer + rc;
528 smtp_inptr = smtp_inbuffer;
529 return TRUE;
530 }
531
532 /*************************************************
533 * SMTP version of getc() *
534 *************************************************/
535
536 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
537 it flushes the output, and refills the buffer, with a timeout. The signal
538 handler is set appropriately by the calling function. This function is not used
539 after a connection has negotiated itself into an TLS/SSL state.
540
541 Arguments: lim Maximum amount to read/buffer
542 Returns: the next character or EOF
543 */
544
545 int
546 smtp_getc(unsigned lim)
547 {
548 if (smtp_inptr >= smtp_inend)
549 if (!smtp_refill(lim))
550 return EOF;
551 return *smtp_inptr++;
552 }
553
554 uschar *
555 smtp_getbuf(unsigned * len)
556 {
557 unsigned size;
558 uschar * buf;
559
560 if (smtp_inptr >= smtp_inend)
561 if (!smtp_refill(*len))
562 { *len = 0; return NULL; }
563
564 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
565 buf = smtp_inptr;
566 smtp_inptr += size;
567 *len = size;
568 return buf;
569 }
570
571 void
572 smtp_get_cache(void)
573 {
574 #ifndef DISABLE_DKIM
575 int n = smtp_inend - smtp_inptr;
576 if (n > 0)
577 dkim_exim_verify_feed(smtp_inptr, n);
578 #endif
579 }
580
581
582 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
583 previous BDAT chunk and getting new ones when we run out. Uses the
584 underlying smtp_getc or tls_getc both for that and for getting the
585 (buffered) data byte. EOD signals (an expected) no further data.
586 ERR signals a protocol error, and EOF a closed input stream.
587
588 Called from read_bdat_smtp() in receive.c for the message body, but also
589 by the headers read loop in receive_msg(); manipulates chunking_state
590 to handle the BDAT command/response.
591 Placed here due to the correlation with the above smtp_getc(), which it wraps,
592 and also by the need to do smtp command/response handling.
593
594 Arguments: lim (ignored)
595 Returns: the next character or ERR, EOD or EOF
596 */
597
598 int
599 bdat_getc(unsigned lim)
600 {
601 uschar * user_msg = NULL;
602 uschar * log_msg;
603
604 for(;;)
605 {
606 #ifndef DISABLE_DKIM
607 unsigned dkim_save;
608 #endif
609
610 if (chunking_data_left > 0)
611 return lwr_receive_getc(chunking_data_left--);
612
613 receive_getc = lwr_receive_getc;
614 receive_getbuf = lwr_receive_getbuf;
615 receive_ungetc = lwr_receive_ungetc;
616 #ifndef DISABLE_DKIM
617 dkim_save = dkim_collect_input;
618 dkim_collect_input = 0;
619 #endif
620
621 /* Unless PIPELINING was offered, there should be no next command
622 until after we ack that chunk */
623
624 if (!smtp_in_pipelining_advertised && !check_sync())
625 {
626 unsigned n = smtp_inend - smtp_inptr;
627 if (n > 32) n = 32;
628
629 incomplete_transaction_log(US"sync failure");
630 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
631 "(next input sent too soon: pipelining was not advertised): "
632 "rejected \"%s\" %s next input=\"%s\"%s",
633 smtp_cmd_buffer, host_and_ident(TRUE),
634 string_printing(string_copyn(smtp_inptr, n)),
635 smtp_inend - smtp_inptr > n ? "..." : "");
636 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
637 US"SMTP synchronization error");
638 goto repeat_until_rset;
639 }
640
641 /* If not the last, ack the received chunk. The last response is delayed
642 until after the data ACL decides on it */
643
644 if (chunking_state == CHUNKING_LAST)
645 {
646 #ifndef DISABLE_DKIM
647 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
648 #endif
649 return EOD;
650 }
651
652 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
653 chunking_state = CHUNKING_OFFERED;
654 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
655
656 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
657 QUIT, RSET or NOOP but handling them seems obvious */
658
659 next_cmd:
660 switch(smtp_read_command(TRUE, 1))
661 {
662 default:
663 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
664 US"only BDAT permissible after non-LAST BDAT");
665
666 repeat_until_rset:
667 switch(smtp_read_command(TRUE, 1))
668 {
669 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
670 case EOF_CMD: return EOF;
671 case RSET_CMD: smtp_rset_handler(); return ERR;
672 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
673 US"only RSET accepted now") > 0)
674 return EOF;
675 goto repeat_until_rset;
676 }
677
678 case QUIT_CMD:
679 smtp_quit_handler(&user_msg, &log_msg);
680 /*FALLTHROUGH*/
681 case EOF_CMD:
682 return EOF;
683
684 case RSET_CMD:
685 smtp_rset_handler();
686 return ERR;
687
688 case NOOP_CMD:
689 HAD(SCH_NOOP);
690 smtp_printf("250 OK\r\n", FALSE);
691 goto next_cmd;
692
693 case BDAT_CMD:
694 {
695 int n;
696
697 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
698 {
699 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
700 US"missing size for BDAT command");
701 return ERR;
702 }
703 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
704 ? CHUNKING_LAST : CHUNKING_ACTIVE;
705 chunking_data_left = chunking_datasize;
706 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
707 (int)chunking_state, chunking_data_left);
708
709 if (chunking_datasize == 0)
710 if (chunking_state == CHUNKING_LAST)
711 return EOD;
712 else
713 {
714 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
715 US"zero size for BDAT command");
716 goto repeat_until_rset;
717 }
718
719 receive_getc = bdat_getc;
720 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
721 receive_ungetc = bdat_ungetc;
722 #ifndef DISABLE_DKIM
723 dkim_collect_input = dkim_save;
724 #endif
725 break; /* to top of main loop */
726 }
727 }
728 }
729 }
730
731 uschar *
732 bdat_getbuf(unsigned * len)
733 {
734 uschar * buf;
735
736 if (chunking_data_left <= 0)
737 { *len = 0; return NULL; }
738
739 if (*len > chunking_data_left) *len = chunking_data_left;
740 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
741 chunking_data_left -= *len;
742 return buf;
743 }
744
745 void
746 bdat_flush_data(void)
747 {
748 while (chunking_data_left)
749 {
750 unsigned n = chunking_data_left;
751 if (!bdat_getbuf(&n)) break;
752 }
753
754 receive_getc = lwr_receive_getc;
755 receive_getbuf = lwr_receive_getbuf;
756 receive_ungetc = lwr_receive_ungetc;
757
758 if (chunking_state != CHUNKING_LAST)
759 {
760 chunking_state = CHUNKING_OFFERED;
761 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
762 }
763 }
764
765
766
767
768 /*************************************************
769 * SMTP version of ungetc() *
770 *************************************************/
771
772 /* Puts a character back in the input buffer. Only ever
773 called once.
774
775 Arguments:
776 ch the character
777
778 Returns: the character
779 */
780
781 int
782 smtp_ungetc(int ch)
783 {
784 *--smtp_inptr = ch;
785 return ch;
786 }
787
788
789 int
790 bdat_ungetc(int ch)
791 {
792 chunking_data_left++;
793 return lwr_receive_ungetc(ch);
794 }
795
796
797
798 /*************************************************
799 * SMTP version of feof() *
800 *************************************************/
801
802 /* Tests for a previous EOF
803
804 Arguments: none
805 Returns: non-zero if the eof flag is set
806 */
807
808 int
809 smtp_feof(void)
810 {
811 return smtp_had_eof;
812 }
813
814
815
816
817 /*************************************************
818 * SMTP version of ferror() *
819 *************************************************/
820
821 /* Tests for a previous read error, and returns with errno
822 restored to what it was when the error was detected.
823
824 Arguments: none
825 Returns: non-zero if the error flag is set
826 */
827
828 int
829 smtp_ferror(void)
830 {
831 errno = smtp_had_error;
832 return smtp_had_error;
833 }
834
835
836
837 /*************************************************
838 * Test for characters in the SMTP buffer *
839 *************************************************/
840
841 /* Used at the end of a message
842
843 Arguments: none
844 Returns: TRUE/FALSE
845 */
846
847 BOOL
848 smtp_buffered(void)
849 {
850 return smtp_inptr < smtp_inend;
851 }
852
853
854
855 /*************************************************
856 * Write formatted string to SMTP channel *
857 *************************************************/
858
859 /* This is a separate function so that we don't have to repeat everything for
860 TLS support or debugging. It is global so that the daemon and the
861 authentication functions can use it. It does not return any error indication,
862 because major problems such as dropped connections won't show up till an output
863 flush for non-TLS connections. The smtp_fflush() function is available for
864 checking that: for convenience, TLS output errors are remembered here so that
865 they are also picked up later by smtp_fflush().
866
867 Arguments:
868 format format string
869 more further data expected
870 ... optional arguments
871
872 Returns: nothing
873 */
874
875 void
876 smtp_printf(const char *format, BOOL more, ...)
877 {
878 va_list ap;
879
880 va_start(ap, more);
881 smtp_vprintf(format, more, ap);
882 va_end(ap);
883 }
884
885 /* This is split off so that verify.c:respond_printf() can, in effect, call
886 smtp_printf(), bearing in mind that in C a vararg function can't directly
887 call another vararg function, only a function which accepts a va_list. */
888
889 void
890 smtp_vprintf(const char *format, BOOL more, va_list ap)
891 {
892 BOOL yield;
893
894 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
895
896 DEBUG(D_receive)
897 {
898 void *reset_point = store_get(0);
899 uschar *msg_copy, *cr, *end;
900 msg_copy = string_copy(big_buffer);
901 end = msg_copy + Ustrlen(msg_copy);
902 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
903 memmove(cr, cr + 1, (end--) - cr);
904 debug_printf("SMTP>> %s", msg_copy);
905 store_reset(reset_point);
906 }
907
908 if (!yield)
909 {
910 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
911 smtp_closedown(US"Unexpected error");
912 exim_exit(EXIT_FAILURE, NULL);
913 }
914
915 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
916 have had the same. Note: this code is also present in smtp_respond(). It would
917 be tidier to have it only in one place, but when it was added, it was easier to
918 do it that way, so as not to have to mess with the code for the RCPT command,
919 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
920
921 if (rcpt_in_progress)
922 {
923 if (rcpt_smtp_response == NULL)
924 rcpt_smtp_response = string_copy(big_buffer);
925 else if (rcpt_smtp_response_same &&
926 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
927 rcpt_smtp_response_same = FALSE;
928 rcpt_in_progress = FALSE;
929 }
930
931 /* Now write the string */
932
933 #ifdef SUPPORT_TLS
934 if (tls_in.active.sock >= 0)
935 {
936 if (tls_write(NULL, big_buffer, Ustrlen(big_buffer), more) < 0)
937 smtp_write_error = -1;
938 }
939 else
940 #endif
941
942 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
943 }
944
945
946
947 /*************************************************
948 * Flush SMTP out and check for error *
949 *************************************************/
950
951 /* This function isn't currently used within Exim (it detects errors when it
952 tries to read the next SMTP input), but is available for use in local_scan().
953 For non-TLS connections, it flushes the output and checks for errors. For
954 TLS-connections, it checks for a previously-detected TLS write error.
955
956 Arguments: none
957 Returns: 0 for no error; -1 after an error
958 */
959
960 int
961 smtp_fflush(void)
962 {
963 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
964 return smtp_write_error;
965 }
966
967
968
969 /*************************************************
970 * SMTP command read timeout *
971 *************************************************/
972
973 /* Signal handler for timing out incoming SMTP commands. This attempts to
974 finish off tidily.
975
976 Argument: signal number (SIGALRM)
977 Returns: nothing
978 */
979
980 static void
981 command_timeout_handler(int sig)
982 {
983 had_command_timeout = sig;
984 }
985
986
987
988 /*************************************************
989 * SIGTERM received *
990 *************************************************/
991
992 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
993
994 Argument: signal number (SIGTERM)
995 Returns: nothing
996 */
997
998 static void
999 command_sigterm_handler(int sig)
1000 {
1001 had_command_sigterm = sig;
1002 }
1003
1004
1005
1006
1007 #ifdef SUPPORT_PROXY
1008 /*************************************************
1009 * Restore socket timeout to previous value *
1010 *************************************************/
1011 /* If the previous value was successfully retrieved, restore
1012 it before returning control to the non-proxy routines
1013
1014 Arguments: fd - File descriptor for input
1015 get_ok - Successfully retrieved previous values
1016 tvtmp - Time struct with previous values
1017 vslen - Length of time struct
1018 Returns: none
1019 */
1020 static void
1021 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1022 {
1023 if (get_ok == 0)
1024 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1025 }
1026
1027 /*************************************************
1028 * Check if host is required proxy host *
1029 *************************************************/
1030 /* The function determines if inbound host will be a regular smtp host
1031 or if it is configured that it must use Proxy Protocol. A local
1032 connection cannot.
1033
1034 Arguments: none
1035 Returns: bool
1036 */
1037
1038 static BOOL
1039 check_proxy_protocol_host()
1040 {
1041 int rc;
1042
1043 if ( sender_host_address
1044 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1045 sender_host_address, NULL)) == OK)
1046 {
1047 DEBUG(D_receive)
1048 debug_printf("Detected proxy protocol configured host\n");
1049 proxy_session = TRUE;
1050 }
1051 return proxy_session;
1052 }
1053
1054
1055 /*************************************************
1056 * Read data until newline or end of buffer *
1057 *************************************************/
1058 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1059 read an entire buffer and assume there will be nothing past a proxy protocol
1060 header. Our approach normally is to use stdio, but again that relies upon
1061 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1062 reading _nothing_ before client TLS handshake. So we don't want to use the
1063 usual buffering reads which may read enough to block TLS starting.
1064
1065 So unfortunately we're down to "read one byte at a time, with a syscall each,
1066 and expect a little overhead", for all proxy-opened connections which are v1,
1067 just to handle the TLS-on-connect case. Since SSL functions wrap the
1068 underlying fd, we can't assume that we can feed them any already-read content.
1069
1070 We need to know where to read to, the max capacity, and we'll read until we
1071 get a CR and one more character. Let the caller scream if it's CR+!LF.
1072
1073 Return the amount read.
1074 */
1075
1076 static int
1077 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1078 {
1079 uschar *to = base + already;
1080 uschar *cr;
1081 int have = 0;
1082 int ret;
1083 int last = 0;
1084
1085 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1086 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1087
1088 cr = memchr(base, '\r', already);
1089 if (cr != NULL)
1090 {
1091 if ((cr - base) < already - 1)
1092 {
1093 /* \r and presumed \n already within what we have; probably not
1094 actually proxy protocol, but abort cleanly. */
1095 return 0;
1096 }
1097 /* \r is last character read, just need one more. */
1098 last = 1;
1099 }
1100
1101 while (capacity > 0)
1102 {
1103 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1104 if (ret == -1)
1105 return -1;
1106 have++;
1107 if (last)
1108 return have;
1109 if (*to == '\r')
1110 last = 1;
1111 capacity--;
1112 to++;
1113 }
1114
1115 /* reached end without having room for a final newline, abort */
1116 errno = EOVERFLOW;
1117 return -1;
1118 }
1119
1120 /*************************************************
1121 * Setup host for proxy protocol *
1122 *************************************************/
1123 /* The function configures the connection based on a header from the
1124 inbound host to use Proxy Protocol. The specification is very exact
1125 so exit with an error if do not find the exact required pieces. This
1126 includes an incorrect number of spaces separating args.
1127
1128 Arguments: none
1129 Returns: Boolean success
1130 */
1131
1132 static void
1133 setup_proxy_protocol_host()
1134 {
1135 union {
1136 struct {
1137 uschar line[108];
1138 } v1;
1139 struct {
1140 uschar sig[12];
1141 uint8_t ver_cmd;
1142 uint8_t fam;
1143 uint16_t len;
1144 union {
1145 struct { /* TCP/UDP over IPv4, len = 12 */
1146 uint32_t src_addr;
1147 uint32_t dst_addr;
1148 uint16_t src_port;
1149 uint16_t dst_port;
1150 } ip4;
1151 struct { /* TCP/UDP over IPv6, len = 36 */
1152 uint8_t src_addr[16];
1153 uint8_t dst_addr[16];
1154 uint16_t src_port;
1155 uint16_t dst_port;
1156 } ip6;
1157 struct { /* AF_UNIX sockets, len = 216 */
1158 uschar src_addr[108];
1159 uschar dst_addr[108];
1160 } unx;
1161 } addr;
1162 } v2;
1163 } hdr;
1164
1165 /* Temp variables used in PPv2 address:port parsing */
1166 uint16_t tmpport;
1167 char tmpip[INET_ADDRSTRLEN];
1168 struct sockaddr_in tmpaddr;
1169 char tmpip6[INET6_ADDRSTRLEN];
1170 struct sockaddr_in6 tmpaddr6;
1171
1172 /* We can't read "all data until end" because while SMTP is
1173 server-speaks-first, the TLS handshake is client-speaks-first, so for
1174 TLS-on-connect ports the proxy protocol header will usually be immediately
1175 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1176 reinject data for reading by those. So instead we first read "enough to be
1177 safely read within the header, and figure out how much more to read".
1178 For v1 we will later read to the end-of-line, for v2 we will read based upon
1179 the stated length.
1180
1181 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1182 data is needed total. For v1, where the line looks like:
1183 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1184
1185 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1186 We seem to support that. So, if we read 14 octets then we can tell if we're
1187 v2 or v1. If we're v1, we can continue reading as normal.
1188
1189 If we're v2, we can't slurp up the entire header. We need the length in the
1190 15th & 16th octets, then to read everything after that.
1191
1192 So to safely handle v1 and v2, with client-sent-first supported correctly,
1193 we have to do a minimum of 3 read calls, not 1. Eww.
1194 */
1195
1196 #define PROXY_INITIAL_READ 14
1197 #define PROXY_V2_HEADER_SIZE 16
1198 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1199 # error Code bug in sizes of data to read for proxy usage
1200 #endif
1201
1202 int get_ok = 0;
1203 int size, ret;
1204 int fd = fileno(smtp_in);
1205 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1206 uschar * iptype; /* To display debug info */
1207 struct timeval tv;
1208 struct timeval tvtmp;
1209 socklen_t vslen = sizeof(struct timeval);
1210 BOOL yield = FALSE;
1211
1212 /* Save current socket timeout values */
1213 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1214
1215 /* Proxy Protocol host must send header within a short time
1216 (default 3 seconds) or it's considered invalid */
1217 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1218 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1219 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1220 goto bad;
1221
1222 do
1223 {
1224 /* The inbound host was declared to be a Proxy Protocol host, so
1225 don't do a PEEK into the data, actually slurp up enough to be
1226 "safe". Can't take it all because TLS-on-connect clients follow
1227 immediately with TLS handshake. */
1228 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1229 }
1230 while (ret == -1 && errno == EINTR);
1231
1232 if (ret == -1)
1233 goto proxyfail;
1234
1235 /* For v2, handle reading the length, and then the rest. */
1236 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1237 {
1238 int retmore;
1239 uint8_t ver;
1240
1241 /* First get the length fields. */
1242 do
1243 {
1244 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1245 } while (retmore == -1 && errno == EINTR);
1246 if (retmore == -1)
1247 goto proxyfail;
1248 ret += retmore;
1249
1250 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1251
1252 /* May 2014: haproxy combined the version and command into one byte to
1253 allow two full bytes for the length field in order to proxy SSL
1254 connections. SSL Proxy is not supported in this version of Exim, but
1255 must still separate values here. */
1256
1257 if (ver != 0x02)
1258 {
1259 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1260 goto proxyfail;
1261 }
1262
1263 /* The v2 header will always be 16 bytes per the spec. */
1264 size = 16 + ntohs(hdr.v2.len);
1265 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1266 size, (int)sizeof(hdr));
1267
1268 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1269 amount that we need. Double-check that the size is not unreasonable, then
1270 get the rest. */
1271 if (size > sizeof(hdr))
1272 {
1273 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1274 goto proxyfail;
1275 }
1276
1277 do
1278 {
1279 do
1280 {
1281 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1282 } while (retmore == -1 && errno == EINTR);
1283 if (retmore == -1)
1284 goto proxyfail;
1285 ret += retmore;
1286 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1287 } while (ret < size);
1288
1289 } /* end scope for getting rest of data for v2 */
1290
1291 /* At this point: if PROXYv2, we've read the exact size required for all data;
1292 if PROXYv1 then we've read "less than required for any valid line" and should
1293 read the rest". */
1294
1295 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1296 {
1297 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1298
1299 switch (cmd)
1300 {
1301 case 0x01: /* PROXY command */
1302 switch (hdr.v2.fam)
1303 {
1304 case 0x11: /* TCPv4 address type */
1305 iptype = US"IPv4";
1306 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1307 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1308 if (!string_is_ip_address(US tmpip, NULL))
1309 {
1310 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1311 goto proxyfail;
1312 }
1313 proxy_local_address = sender_host_address;
1314 sender_host_address = string_copy(US tmpip);
1315 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1316 proxy_local_port = sender_host_port;
1317 sender_host_port = tmpport;
1318 /* Save dest ip/port */
1319 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1320 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1321 if (!string_is_ip_address(US tmpip, NULL))
1322 {
1323 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1324 goto proxyfail;
1325 }
1326 proxy_external_address = string_copy(US tmpip);
1327 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1328 proxy_external_port = tmpport;
1329 goto done;
1330 case 0x21: /* TCPv6 address type */
1331 iptype = US"IPv6";
1332 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1333 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1334 if (!string_is_ip_address(US tmpip6, NULL))
1335 {
1336 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1337 goto proxyfail;
1338 }
1339 proxy_local_address = sender_host_address;
1340 sender_host_address = string_copy(US tmpip6);
1341 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1342 proxy_local_port = sender_host_port;
1343 sender_host_port = tmpport;
1344 /* Save dest ip/port */
1345 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1346 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1347 if (!string_is_ip_address(US tmpip6, NULL))
1348 {
1349 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1350 goto proxyfail;
1351 }
1352 proxy_external_address = string_copy(US tmpip6);
1353 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1354 proxy_external_port = tmpport;
1355 goto done;
1356 default:
1357 DEBUG(D_receive)
1358 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1359 hdr.v2.fam);
1360 goto proxyfail;
1361 }
1362 /* Unsupported protocol, keep local connection address */
1363 break;
1364 case 0x00: /* LOCAL command */
1365 /* Keep local connection address for LOCAL */
1366 iptype = US"local";
1367 break;
1368 default:
1369 DEBUG(D_receive)
1370 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1371 goto proxyfail;
1372 }
1373 }
1374 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1375 {
1376 uschar *p;
1377 uschar *end;
1378 uschar *sp; /* Utility variables follow */
1379 int tmp_port;
1380 int r2;
1381 char *endc;
1382
1383 /* get the rest of the line */
1384 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1385 if (r2 == -1)
1386 goto proxyfail;
1387 ret += r2;
1388
1389 p = string_copy(hdr.v1.line);
1390 end = memchr(p, '\r', ret - 1);
1391
1392 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1393 {
1394 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1395 goto proxyfail;
1396 }
1397 *end = '\0'; /* Terminate the string */
1398 size = end + 2 - p; /* Skip header + CRLF */
1399 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1400 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1401 /* Step through the string looking for the required fields. Ensure
1402 strict adherence to required formatting, exit for any error. */
1403 p += 5;
1404 if (!isspace(*(p++)))
1405 {
1406 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1407 goto proxyfail;
1408 }
1409 if (!Ustrncmp(p, CCS"TCP4", 4))
1410 iptype = US"IPv4";
1411 else if (!Ustrncmp(p,CCS"TCP6", 4))
1412 iptype = US"IPv6";
1413 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1414 {
1415 iptype = US"Unknown";
1416 goto done;
1417 }
1418 else
1419 {
1420 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1421 goto proxyfail;
1422 }
1423
1424 p += Ustrlen(iptype);
1425 if (!isspace(*(p++)))
1426 {
1427 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1428 goto proxyfail;
1429 }
1430 /* Find the end of the arg */
1431 if ((sp = Ustrchr(p, ' ')) == NULL)
1432 {
1433 DEBUG(D_receive)
1434 debug_printf("Did not find proxied src %s\n", iptype);
1435 goto proxyfail;
1436 }
1437 *sp = '\0';
1438 if(!string_is_ip_address(p, NULL))
1439 {
1440 DEBUG(D_receive)
1441 debug_printf("Proxied src arg is not an %s address\n", iptype);
1442 goto proxyfail;
1443 }
1444 proxy_local_address = sender_host_address;
1445 sender_host_address = p;
1446 p = sp + 1;
1447 if ((sp = Ustrchr(p, ' ')) == NULL)
1448 {
1449 DEBUG(D_receive)
1450 debug_printf("Did not find proxy dest %s\n", iptype);
1451 goto proxyfail;
1452 }
1453 *sp = '\0';
1454 if(!string_is_ip_address(p, NULL))
1455 {
1456 DEBUG(D_receive)
1457 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1458 goto proxyfail;
1459 }
1460 proxy_external_address = p;
1461 p = sp + 1;
1462 if ((sp = Ustrchr(p, ' ')) == NULL)
1463 {
1464 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1465 goto proxyfail;
1466 }
1467 *sp = '\0';
1468 tmp_port = strtol(CCS p, &endc, 10);
1469 if (*endc || tmp_port == 0)
1470 {
1471 DEBUG(D_receive)
1472 debug_printf("Proxied src port '%s' not an integer\n", p);
1473 goto proxyfail;
1474 }
1475 proxy_local_port = sender_host_port;
1476 sender_host_port = tmp_port;
1477 p = sp + 1;
1478 if ((sp = Ustrchr(p, '\0')) == NULL)
1479 {
1480 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1481 goto proxyfail;
1482 }
1483 tmp_port = strtol(CCS p, &endc, 10);
1484 if (*endc || tmp_port == 0)
1485 {
1486 DEBUG(D_receive)
1487 debug_printf("Proxy dest port '%s' not an integer\n", p);
1488 goto proxyfail;
1489 }
1490 proxy_external_port = tmp_port;
1491 /* Already checked for /r /n above. Good V1 header received. */
1492 }
1493 else
1494 {
1495 /* Wrong protocol */
1496 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1497 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1498 goto proxyfail;
1499 }
1500
1501 done:
1502 DEBUG(D_receive)
1503 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1504 yield = proxy_session;
1505
1506 /* Don't flush any potential buffer contents. Any input on proxyfail
1507 should cause a synchronization failure */
1508
1509 proxyfail:
1510 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1511
1512 bad:
1513 if (yield)
1514 {
1515 sender_host_name = NULL;
1516 (void) host_name_lookup();
1517 host_build_sender_fullhost();
1518 }
1519 else
1520 {
1521 proxy_session_failed = TRUE;
1522 DEBUG(D_receive)
1523 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1524 }
1525
1526 return;
1527 }
1528 #endif
1529
1530 /*************************************************
1531 * Read one command line *
1532 *************************************************/
1533
1534 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1535 There are sites that don't do this, and in any case internal SMTP probably
1536 should check only for LF. Consequently, we check here for LF only. The line
1537 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1538 an unknown command. The command is read into the global smtp_cmd_buffer so that
1539 it is available via $smtp_command.
1540
1541 The character reading routine sets up a timeout for each block actually read
1542 from the input (which may contain more than one command). We set up a special
1543 signal handler that closes down the session on a timeout. Control does not
1544 return when it runs.
1545
1546 Arguments:
1547 check_sync if TRUE, check synchronization rules if global option is TRUE
1548 buffer_lim maximum to buffer in lower layer
1549
1550 Returns: a code identifying the command (enumerated above)
1551 */
1552
1553 static int
1554 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1555 {
1556 int c;
1557 int ptr = 0;
1558 smtp_cmd_list *p;
1559 BOOL hadnull = FALSE;
1560
1561 had_command_timeout = 0;
1562 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1563
1564 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1565 {
1566 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1567 {
1568 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1569 return OTHER_CMD;
1570 }
1571 if (c == 0)
1572 {
1573 hadnull = TRUE;
1574 c = '?';
1575 }
1576 smtp_cmd_buffer[ptr++] = c;
1577 }
1578
1579 receive_linecount++; /* For BSMTP errors */
1580 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1581
1582 /* If hit end of file, return pseudo EOF command. Whether we have a
1583 part-line already read doesn't matter, since this is an error state. */
1584
1585 if (c == EOF) return EOF_CMD;
1586
1587 /* Remove any CR and white space at the end of the line, and terminate the
1588 string. */
1589
1590 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1591 smtp_cmd_buffer[ptr] = 0;
1592
1593 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1594
1595 /* NULLs are not allowed in SMTP commands */
1596
1597 if (hadnull) return BADCHAR_CMD;
1598
1599 /* Scan command list and return identity, having set the data pointer
1600 to the start of the actual data characters. Check for SMTP synchronization
1601 if required. */
1602
1603 for (p = cmd_list; p < cmd_list_end; p++)
1604 {
1605 #ifdef SUPPORT_PROXY
1606 /* Only allow QUIT command if Proxy Protocol parsing failed */
1607 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1608 continue;
1609 #endif
1610 if ( p->len
1611 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1612 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1613 || smtp_cmd_buffer[p->len] == 0
1614 || smtp_cmd_buffer[p->len] == ' '
1615 ) )
1616 {
1617 if (smtp_inptr < smtp_inend && /* Outstanding input */
1618 p->cmd < sync_cmd_limit && /* Command should sync */
1619 check_sync && /* Local flag set */
1620 smtp_enforce_sync && /* Global flag set */
1621 sender_host_address != NULL && /* Not local input */
1622 !sender_host_notsocket) /* Really is a socket */
1623 return BADSYN_CMD;
1624
1625 /* The variables $smtp_command and $smtp_command_argument point into the
1626 unmodified input buffer. A copy of the latter is taken for actual
1627 processing, so that it can be chopped up into separate parts if necessary,
1628 for example, when processing a MAIL command options such as SIZE that can
1629 follow the sender address. */
1630
1631 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1632 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1633 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1634 smtp_cmd_data = smtp_data_buffer;
1635
1636 /* Count non-mail commands from those hosts that are controlled in this
1637 way. The default is all hosts. We don't waste effort checking the list
1638 until we get a non-mail command, but then cache the result to save checking
1639 again. If there's a DEFER while checking the host, assume it's in the list.
1640
1641 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1642 start of each incoming message by fiddling with the value in the table. */
1643
1644 if (!p->is_mail_cmd)
1645 {
1646 if (count_nonmail == TRUE_UNSET) count_nonmail =
1647 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1648 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1649 return TOO_MANY_NONMAIL_CMD;
1650 }
1651
1652 /* If there is data for a command that does not expect it, generate the
1653 error here. */
1654
1655 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1656 }
1657 }
1658
1659 #ifdef SUPPORT_PROXY
1660 /* Only allow QUIT command if Proxy Protocol parsing failed */
1661 if (proxy_session && proxy_session_failed)
1662 return PROXY_FAIL_IGNORE_CMD;
1663 #endif
1664
1665 /* Enforce synchronization for unknown commands */
1666
1667 if ( smtp_inptr < smtp_inend /* Outstanding input */
1668 && check_sync /* Local flag set */
1669 && smtp_enforce_sync /* Global flag set */
1670 && sender_host_address /* Not local input */
1671 && !sender_host_notsocket) /* Really is a socket */
1672 return BADSYN_CMD;
1673
1674 return OTHER_CMD;
1675 }
1676
1677
1678
1679 /*************************************************
1680 * Forced closedown of call *
1681 *************************************************/
1682
1683 /* This function is called from log.c when Exim is dying because of a serious
1684 disaster, and also from some other places. If an incoming non-batched SMTP
1685 channel is open, it swallows the rest of the incoming message if in the DATA
1686 phase, sends the reply string, and gives an error to all subsequent commands
1687 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1688 smtp_in.
1689
1690 Arguments:
1691 message SMTP reply string to send, excluding the code
1692
1693 Returns: nothing
1694 */
1695
1696 void
1697 smtp_closedown(uschar *message)
1698 {
1699 if (!smtp_in || smtp_batched_input) return;
1700 receive_swallow_smtp();
1701 smtp_printf("421 %s\r\n", FALSE, message);
1702
1703 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1704 {
1705 case EOF_CMD:
1706 return;
1707
1708 case QUIT_CMD:
1709 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1710 mac_smtp_fflush();
1711 return;
1712
1713 case RSET_CMD:
1714 smtp_printf("250 Reset OK\r\n", FALSE);
1715 break;
1716
1717 default:
1718 smtp_printf("421 %s\r\n", FALSE, message);
1719 break;
1720 }
1721 }
1722
1723
1724
1725
1726 /*************************************************
1727 * Set up connection info for logging *
1728 *************************************************/
1729
1730 /* This function is called when logging information about an SMTP connection.
1731 It sets up appropriate source information, depending on the type of connection.
1732 If sender_fullhost is NULL, we are at a very early stage of the connection;
1733 just use the IP address.
1734
1735 Argument: none
1736 Returns: a string describing the connection
1737 */
1738
1739 uschar *
1740 smtp_get_connection_info(void)
1741 {
1742 const uschar * hostname = sender_fullhost
1743 ? sender_fullhost : sender_host_address;
1744
1745 if (host_checking)
1746 return string_sprintf("SMTP connection from %s", hostname);
1747
1748 if (sender_host_unknown || sender_host_notsocket)
1749 return string_sprintf("SMTP connection from %s", sender_ident);
1750
1751 if (is_inetd)
1752 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1753
1754 if (LOGGING(incoming_interface) && interface_address != NULL)
1755 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1756 interface_address, interface_port);
1757
1758 return string_sprintf("SMTP connection from %s", hostname);
1759 }
1760
1761
1762
1763 #ifdef SUPPORT_TLS
1764 /* Append TLS-related information to a log line
1765
1766 Arguments:
1767 g String under construction: allocated string to extend, or NULL
1768
1769 Returns: Allocated string or NULL
1770 */
1771 static gstring *
1772 s_tlslog(gstring * g)
1773 {
1774 if (LOGGING(tls_cipher) && tls_in.cipher)
1775 g = string_append(g, 2, US" X=", tls_in.cipher);
1776 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1777 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1778 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1779 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1780 if (LOGGING(tls_sni) && tls_in.sni)
1781 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1782 return g;
1783 }
1784 #endif
1785
1786 /*************************************************
1787 * Log lack of MAIL if so configured *
1788 *************************************************/
1789
1790 /* This function is called when an SMTP session ends. If the log selector
1791 smtp_no_mail is set, write a log line giving some details of what has happened
1792 in the SMTP session.
1793
1794 Arguments: none
1795 Returns: nothing
1796 */
1797
1798 void
1799 smtp_log_no_mail(void)
1800 {
1801 int i;
1802 uschar * sep, * s;
1803 gstring * g = NULL;
1804
1805 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1806 return;
1807
1808 if (sender_host_authenticated)
1809 {
1810 g = string_append(g, 2, US" A=", sender_host_authenticated);
1811 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1812 }
1813
1814 #ifdef SUPPORT_TLS
1815 g = s_tlslog(g);
1816 #endif
1817
1818 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1819
1820 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1821 if (smtp_connection_had[i] != SCH_NONE)
1822 {
1823 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1824 sep = US",";
1825 }
1826
1827 for (i = 0; i < smtp_ch_index; i++)
1828 {
1829 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1830 sep = US",";
1831 }
1832
1833 if (!(s = string_from_gstring(g))) s = US"";
1834
1835 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1836 tcp_in_fastopen ? US"TFO " : US"",
1837 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1838 }
1839
1840
1841 /* Return list of recent smtp commands */
1842
1843 uschar *
1844 smtp_cmd_hist(void)
1845 {
1846 int i;
1847 gstring * list = NULL;
1848 uschar * s;
1849
1850 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1851 if (smtp_connection_had[i] != SCH_NONE)
1852 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1853
1854 for (i = 0; i < smtp_ch_index; i++)
1855 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1856
1857 s = string_from_gstring(list);
1858 return s ? s : US"";
1859 }
1860
1861
1862
1863
1864 /*************************************************
1865 * Check HELO line and set sender_helo_name *
1866 *************************************************/
1867
1868 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1869 the domain name of the sending host, or an ip literal in square brackets. The
1870 argument is placed in sender_helo_name, which is in malloc store, because it
1871 must persist over multiple incoming messages. If helo_accept_junk is set, this
1872 host is permitted to send any old junk (needed for some broken hosts).
1873 Otherwise, helo_allow_chars can be used for rogue characters in general
1874 (typically people want to let in underscores).
1875
1876 Argument:
1877 s the data portion of the line (already past any white space)
1878
1879 Returns: TRUE or FALSE
1880 */
1881
1882 static BOOL
1883 check_helo(uschar *s)
1884 {
1885 uschar *start = s;
1886 uschar *end = s + Ustrlen(s);
1887 BOOL yield = helo_accept_junk;
1888
1889 /* Discard any previous helo name */
1890
1891 if (sender_helo_name)
1892 {
1893 store_free(sender_helo_name);
1894 sender_helo_name = NULL;
1895 }
1896
1897 /* Skip tests if junk is permitted. */
1898
1899 if (!yield)
1900
1901 /* Allow the new standard form for IPv6 address literals, namely,
1902 [IPv6:....], and because someone is bound to use it, allow an equivalent
1903 IPv4 form. Allow plain addresses as well. */
1904
1905 if (*s == '[')
1906 {
1907 if (end[-1] == ']')
1908 {
1909 end[-1] = 0;
1910 if (strncmpic(s, US"[IPv6:", 6) == 0)
1911 yield = (string_is_ip_address(s+6, NULL) == 6);
1912 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1913 yield = (string_is_ip_address(s+6, NULL) == 4);
1914 else
1915 yield = (string_is_ip_address(s+1, NULL) != 0);
1916 end[-1] = ']';
1917 }
1918 }
1919
1920 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1921 that have been configured (usually underscore - sigh). */
1922
1923 else if (*s)
1924 for (yield = TRUE; *s; s++)
1925 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1926 Ustrchr(helo_allow_chars, *s) == NULL)
1927 {
1928 yield = FALSE;
1929 break;
1930 }
1931
1932 /* Save argument if OK */
1933
1934 if (yield) sender_helo_name = string_copy_malloc(start);
1935 return yield;
1936 }
1937
1938
1939
1940
1941
1942 /*************************************************
1943 * Extract SMTP command option *
1944 *************************************************/
1945
1946 /* This function picks the next option setting off the end of smtp_cmd_data. It
1947 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1948 things that can appear there.
1949
1950 Arguments:
1951 name point this at the name
1952 value point this at the data string
1953
1954 Returns: TRUE if found an option
1955 */
1956
1957 static BOOL
1958 extract_option(uschar **name, uschar **value)
1959 {
1960 uschar *n;
1961 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1962 while (isspace(*v)) v--;
1963 v[1] = 0;
1964 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1965 {
1966 /* Take care to not stop at a space embedded in a quoted local-part */
1967
1968 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1969 v--;
1970 }
1971
1972 n = v;
1973 if (*v == '=')
1974 {
1975 while(isalpha(n[-1])) n--;
1976 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1977 if (!isspace(n[-1])) return FALSE;
1978 n[-1] = 0;
1979 }
1980 else
1981 {
1982 n++;
1983 if (v == smtp_cmd_data) return FALSE;
1984 }
1985 *v++ = 0;
1986 *name = n;
1987 *value = v;
1988 return TRUE;
1989 }
1990
1991
1992
1993
1994
1995 /*************************************************
1996 * Reset for new message *
1997 *************************************************/
1998
1999 /* This function is called whenever the SMTP session is reset from
2000 within either of the setup functions; also from the daemon loop.
2001
2002 Argument: the stacking pool storage reset point
2003 Returns: nothing
2004 */
2005
2006 void
2007 smtp_reset(void *reset_point)
2008 {
2009 recipients_list = NULL;
2010 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2011 raw_recipients_count = recipients_count = recipients_list_max = 0;
2012 message_linecount = 0;
2013 message_size = -1;
2014 acl_added_headers = NULL;
2015 acl_removed_headers = NULL;
2016 queue_only_policy = FALSE;
2017 rcpt_smtp_response = NULL;
2018 rcpt_smtp_response_same = TRUE;
2019 rcpt_in_progress = FALSE;
2020 deliver_freeze = FALSE; /* Can be set by ACL */
2021 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2022 fake_response = OK; /* Can be set by ACL */
2023 #ifdef WITH_CONTENT_SCAN
2024 no_mbox_unspool = FALSE; /* Can be set by ACL */
2025 #endif
2026 submission_mode = FALSE; /* Can be set by ACL */
2027 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
2028 active_local_from_check = local_from_check; /* Can be set by ACL */
2029 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2030 sending_ip_address = NULL;
2031 return_path = sender_address = NULL;
2032 sender_data = NULL; /* Can be set by ACL */
2033 deliver_localpart_parent = deliver_localpart_orig = NULL;
2034 deliver_domain_parent = deliver_domain_orig = NULL;
2035 callout_address = NULL;
2036 submission_name = NULL; /* Can be set by ACL */
2037 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2038 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2039 sender_verified_list = NULL; /* No senders verified */
2040 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2041 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2042
2043 authenticated_sender = NULL;
2044 #ifdef EXPERIMENTAL_BRIGHTMAIL
2045 bmi_run = 0;
2046 bmi_verdicts = NULL;
2047 #endif
2048 dnslist_domain = dnslist_matched = NULL;
2049 #ifdef SUPPORT_SPF
2050 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2051 spf_result_guessed = FALSE;
2052 #endif
2053 #ifndef DISABLE_DKIM
2054 dkim_cur_signer = dkim_signers =
2055 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2056 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2057 dkim_disable_verify = FALSE;
2058 dkim_collect_input = 0;
2059 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2060 dkim_key_length = 0;
2061 dkim_verify_signers = US"$dkim_signers";
2062 #endif
2063 #ifdef EXPERIMENTAL_DMARC
2064 dmarc_has_been_checked = dmarc_disable_verify = dmarc_enable_forensic = FALSE;
2065 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2066 dmarc_used_domain = NULL;
2067 #endif
2068 #ifdef EXPERIMENTAL_ARC
2069 arc_state = arc_state_reason = NULL;
2070 #endif
2071 dsn_ret = 0;
2072 dsn_envid = NULL;
2073 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2074 #ifndef DISABLE_PRDR
2075 prdr_requested = FALSE;
2076 #endif
2077 #ifdef SUPPORT_I18N
2078 message_smtputf8 = FALSE;
2079 #endif
2080 body_linecount = body_zerocount = 0;
2081
2082 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2083 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2084 /* Note that ratelimiters_conn persists across resets. */
2085
2086 /* Reset message ACL variables */
2087
2088 acl_var_m = NULL;
2089
2090 /* The message body variables use malloc store. They may be set if this is
2091 not the first message in an SMTP session and the previous message caused them
2092 to be referenced in an ACL. */
2093
2094 if (message_body)
2095 {
2096 store_free(message_body);
2097 message_body = NULL;
2098 }
2099
2100 if (message_body_end)
2101 {
2102 store_free(message_body_end);
2103 message_body_end = NULL;
2104 }
2105
2106 /* Warning log messages are also saved in malloc store. They are saved to avoid
2107 repetition in the same message, but it seems right to repeat them for different
2108 messages. */
2109
2110 while (acl_warn_logged)
2111 {
2112 string_item *this = acl_warn_logged;
2113 acl_warn_logged = acl_warn_logged->next;
2114 store_free(this);
2115 }
2116 store_reset(reset_point);
2117 }
2118
2119
2120
2121
2122
2123 /*************************************************
2124 * Initialize for incoming batched SMTP message *
2125 *************************************************/
2126
2127 /* This function is called from smtp_setup_msg() in the case when
2128 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2129 of messages in one file with SMTP commands between them. All errors must be
2130 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2131 relevant. After an error on a sender, or an invalid recipient, the remainder
2132 of the message is skipped. The value of received_protocol is already set.
2133
2134 Argument: none
2135 Returns: > 0 message successfully started (reached DATA)
2136 = 0 QUIT read or end of file reached
2137 < 0 should not occur
2138 */
2139
2140 static int
2141 smtp_setup_batch_msg(void)
2142 {
2143 int done = 0;
2144 void *reset_point = store_get(0);
2145
2146 /* Save the line count at the start of each transaction - single commands
2147 like HELO and RSET count as whole transactions. */
2148
2149 bsmtp_transaction_linecount = receive_linecount;
2150
2151 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2152
2153 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2154 smtp_reset(reset_point); /* Reset for start of message */
2155
2156 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2157 value. The values are 2 larger than the required yield of the function. */
2158
2159 while (done <= 0)
2160 {
2161 uschar *errmess;
2162 uschar *recipient = NULL;
2163 int start, end, sender_domain, recipient_domain;
2164
2165 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2166 {
2167 /* The HELO/EHLO commands set sender_address_helo if they have
2168 valid data; otherwise they are ignored, except that they do
2169 a reset of the state. */
2170
2171 case HELO_CMD:
2172 case EHLO_CMD:
2173
2174 check_helo(smtp_cmd_data);
2175 /* Fall through */
2176
2177 case RSET_CMD:
2178 cancel_cutthrough_connection(TRUE, US"RSET received");
2179 smtp_reset(reset_point);
2180 bsmtp_transaction_linecount = receive_linecount;
2181 break;
2182
2183
2184 /* The MAIL FROM command requires an address as an operand. All we
2185 do here is to parse it for syntactic correctness. The form "<>" is
2186 a special case which converts into an empty string. The start/end
2187 pointers in the original are not used further for this address, as
2188 it is the canonical extracted address which is all that is kept. */
2189
2190 case MAIL_CMD:
2191 smtp_mailcmd_count++; /* Count for no-mail log */
2192 if (sender_address != NULL)
2193 /* The function moan_smtp_batch() does not return. */
2194 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2195
2196 if (smtp_cmd_data[0] == 0)
2197 /* The function moan_smtp_batch() does not return. */
2198 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2199
2200 /* Reset to start of message */
2201
2202 cancel_cutthrough_connection(TRUE, US"MAIL received");
2203 smtp_reset(reset_point);
2204
2205 /* Apply SMTP rewrite */
2206
2207 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2208 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2209 US"", global_rewrite_rules) : smtp_cmd_data;
2210
2211 /* Extract the address; the TRUE flag allows <> as valid */
2212
2213 raw_sender =
2214 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2215 TRUE);
2216
2217 if (!raw_sender)
2218 /* The function moan_smtp_batch() does not return. */
2219 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2220
2221 sender_address = string_copy(raw_sender);
2222
2223 /* Qualify unqualified sender addresses if permitted to do so. */
2224
2225 if ( !sender_domain
2226 && sender_address[0] != 0 && sender_address[0] != '@')
2227 if (allow_unqualified_sender)
2228 {
2229 sender_address = rewrite_address_qualify(sender_address, FALSE);
2230 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2231 "and rewritten\n", raw_sender);
2232 }
2233 /* The function moan_smtp_batch() does not return. */
2234 else
2235 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2236 "a domain");
2237 break;
2238
2239
2240 /* The RCPT TO command requires an address as an operand. All we do
2241 here is to parse it for syntactic correctness. There may be any number
2242 of RCPT TO commands, specifying multiple senders. We build them all into
2243 a data structure that is in argc/argv format. The start/end values
2244 given by parse_extract_address are not used, as we keep only the
2245 extracted address. */
2246
2247 case RCPT_CMD:
2248 if (!sender_address)
2249 /* The function moan_smtp_batch() does not return. */
2250 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2251
2252 if (smtp_cmd_data[0] == 0)
2253 /* The function moan_smtp_batch() does not return. */
2254 moan_smtp_batch(smtp_cmd_buffer,
2255 "501 RCPT TO must have an address operand");
2256
2257 /* Check maximum number allowed */
2258
2259 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2260 /* The function moan_smtp_batch() does not return. */
2261 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2262 recipients_max_reject? "552": "452");
2263
2264 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2265 recipient address */
2266
2267 recipient = rewrite_existflags & rewrite_smtp
2268 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2269 global_rewrite_rules)
2270 : smtp_cmd_data;
2271
2272 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2273 &recipient_domain, FALSE);
2274
2275 if (!recipient)
2276 /* The function moan_smtp_batch() does not return. */
2277 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2278
2279 /* If the recipient address is unqualified, qualify it if permitted. Then
2280 add it to the list of recipients. */
2281
2282 if (!recipient_domain)
2283 if (allow_unqualified_recipient)
2284 {
2285 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2286 recipient);
2287 recipient = rewrite_address_qualify(recipient, TRUE);
2288 }
2289 /* The function moan_smtp_batch() does not return. */
2290 else
2291 moan_smtp_batch(smtp_cmd_buffer,
2292 "501 recipient address must contain a domain");
2293
2294 receive_add_recipient(recipient, -1);
2295 break;
2296
2297
2298 /* The DATA command is legal only if it follows successful MAIL FROM
2299 and RCPT TO commands. This function is complete when a valid DATA
2300 command is encountered. */
2301
2302 case DATA_CMD:
2303 if (!sender_address || recipients_count <= 0)
2304 /* The function moan_smtp_batch() does not return. */
2305 if (!sender_address)
2306 moan_smtp_batch(smtp_cmd_buffer,
2307 "503 MAIL FROM:<sender> command must precede DATA");
2308 else
2309 moan_smtp_batch(smtp_cmd_buffer,
2310 "503 RCPT TO:<recipient> must precede DATA");
2311 else
2312 {
2313 done = 3; /* DATA successfully achieved */
2314 message_ended = END_NOTENDED; /* Indicate in middle of message */
2315 }
2316 break;
2317
2318
2319 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2320
2321 case VRFY_CMD:
2322 case EXPN_CMD:
2323 case HELP_CMD:
2324 case NOOP_CMD:
2325 case ETRN_CMD:
2326 bsmtp_transaction_linecount = receive_linecount;
2327 break;
2328
2329
2330 case EOF_CMD:
2331 case QUIT_CMD:
2332 done = 2;
2333 break;
2334
2335
2336 case BADARG_CMD:
2337 /* The function moan_smtp_batch() does not return. */
2338 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2339 break;
2340
2341
2342 case BADCHAR_CMD:
2343 /* The function moan_smtp_batch() does not return. */
2344 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2345 break;
2346
2347
2348 default:
2349 /* The function moan_smtp_batch() does not return. */
2350 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2351 break;
2352 }
2353 }
2354
2355 return done - 2; /* Convert yield values */
2356 }
2357
2358
2359
2360
2361 static BOOL
2362 smtp_log_tls_fail(uschar * errstr)
2363 {
2364 uschar * conn_info = smtp_get_connection_info();
2365
2366 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2367 /* I'd like to get separated H= here, but too hard for now */
2368
2369 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2370 return FALSE;
2371 }
2372
2373
2374
2375
2376 #ifdef TCP_FASTOPEN
2377 static void
2378 tfo_in_check(void)
2379 {
2380 # ifdef TCP_INFO
2381 struct tcp_info tinfo;
2382 socklen_t len = sizeof(tinfo);
2383
2384 if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
2385 && tinfo.tcpi_state == TCP_SYN_RECV
2386 )
2387 {
2388 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2389 tcp_in_fastopen = TRUE;
2390 }
2391 # endif
2392 }
2393 #endif
2394
2395
2396 /*************************************************
2397 * Start an SMTP session *
2398 *************************************************/
2399
2400 /* This function is called at the start of an SMTP session. Thereafter,
2401 smtp_setup_msg() is called to initiate each separate message. This
2402 function does host-specific testing, and outputs the banner line.
2403
2404 Arguments: none
2405 Returns: FALSE if the session can not continue; something has
2406 gone wrong, or the connection to the host is blocked
2407 */
2408
2409 BOOL
2410 smtp_start_session(void)
2411 {
2412 int esclen;
2413 uschar *user_msg, *log_msg;
2414 uschar *code, *esc;
2415 uschar *p, *s;
2416 gstring * ss;
2417
2418 gettimeofday(&smtp_connection_start, NULL);
2419 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2420 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2421 smtp_ch_index = 0;
2422
2423 /* Default values for certain variables */
2424
2425 helo_seen = esmtp = helo_accept_junk = FALSE;
2426 smtp_mailcmd_count = 0;
2427 count_nonmail = TRUE_UNSET;
2428 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2429 smtp_delay_mail = smtp_rlm_base;
2430 auth_advertised = FALSE;
2431 smtp_in_pipelining_advertised = FALSE;
2432 pipelining_enable = TRUE;
2433 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2434 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2435
2436 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2437 authentication settings from -oMaa to remain in force. */
2438
2439 if (!host_checking && !sender_host_notsocket)
2440 sender_host_auth_pubname = sender_host_authenticated = NULL;
2441 authenticated_by = NULL;
2442
2443 #ifdef SUPPORT_TLS
2444 tls_in.cipher = tls_in.peerdn = NULL;
2445 tls_in.ourcert = tls_in.peercert = NULL;
2446 tls_in.sni = NULL;
2447 tls_in.ocsp = OCSP_NOT_REQ;
2448 tls_advertised = FALSE;
2449 # ifdef EXPERIMENTAL_REQUIRETLS
2450 requiretls_advertised = FALSE;
2451 # endif
2452 #endif
2453 dsn_advertised = FALSE;
2454 #ifdef SUPPORT_I18N
2455 smtputf8_advertised = FALSE;
2456 #endif
2457
2458 /* Reset ACL connection variables */
2459
2460 acl_var_c = NULL;
2461
2462 /* Allow for trailing 0 in the command and data buffers. */
2463
2464 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2465 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2466 "malloc() failed for SMTP command buffer");
2467
2468 smtp_cmd_buffer[0] = 0;
2469 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2470
2471 /* For batched input, the protocol setting can be overridden from the
2472 command line by a trusted caller. */
2473
2474 if (smtp_batched_input)
2475 {
2476 if (!received_protocol) received_protocol = US"local-bsmtp";
2477 }
2478
2479 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2480 reset later if any of EHLO/AUTH/STARTTLS are received. */
2481
2482 else
2483 received_protocol =
2484 (sender_host_address ? protocols : protocols_local) [pnormal];
2485
2486 /* Set up the buffer for inputting using direct read() calls, and arrange to
2487 call the local functions instead of the standard C ones. Place a NUL at the
2488 end of the buffer to safety-stop C-string reads from it. */
2489
2490 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2491 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2492 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2493
2494 receive_getc = smtp_getc;
2495 receive_getbuf = smtp_getbuf;
2496 receive_get_cache = smtp_get_cache;
2497 receive_ungetc = smtp_ungetc;
2498 receive_feof = smtp_feof;
2499 receive_ferror = smtp_ferror;
2500 receive_smtp_buffered = smtp_buffered;
2501 smtp_inptr = smtp_inend = smtp_inbuffer;
2502 smtp_had_eof = smtp_had_error = 0;
2503
2504 /* Set up the message size limit; this may be host-specific */
2505
2506 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2507 if (expand_string_message)
2508 {
2509 if (thismessage_size_limit == -1)
2510 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2511 "%s", expand_string_message);
2512 else
2513 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2514 "%s", expand_string_message);
2515 smtp_closedown(US"Temporary local problem - please try later");
2516 return FALSE;
2517 }
2518
2519 /* When a message is input locally via the -bs or -bS options, sender_host_
2520 unknown is set unless -oMa was used to force an IP address, in which case it
2521 is checked like a real remote connection. When -bs is used from inetd, this
2522 flag is not set, causing the sending host to be checked. The code that deals
2523 with IP source routing (if configured) is never required for -bs or -bS and
2524 the flag sender_host_notsocket is used to suppress it.
2525
2526 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2527 reserve for certain hosts and/or networks. */
2528
2529 if (!sender_host_unknown)
2530 {
2531 int rc;
2532 BOOL reserved_host = FALSE;
2533
2534 /* Look up IP options (source routing info) on the socket if this is not an
2535 -oMa "host", and if any are found, log them and drop the connection.
2536
2537 Linux (and others now, see below) is different to everyone else, so there
2538 has to be some conditional compilation here. Versions of Linux before 2.1.15
2539 used a structure whose name was "options". Somebody finally realized that
2540 this name was silly, and it got changed to "ip_options". I use the
2541 newer name here, but there is a fudge in the script that sets up os.h
2542 to define a macro in older Linux systems.
2543
2544 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2545 glibc 2, which has chosen ip_opts for the structure name. This is now
2546 really a glibc thing rather than a Linux thing, so the condition name
2547 has been changed to reflect this. It is relevant also to GNU/Hurd.
2548
2549 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2550 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2551 a special macro defined in the os.h file.
2552
2553 Some DGUX versions on older hardware appear not to support IP options at
2554 all, so there is now a general macro which can be set to cut out this
2555 support altogether.
2556
2557 How to do this properly in IPv6 is not yet known. */
2558
2559 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2560
2561 #ifdef GLIBC_IP_OPTIONS
2562 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2563 #define OPTSTYLE 1
2564 #else
2565 #define OPTSTYLE 2
2566 #endif
2567 #elif defined DARWIN_IP_OPTIONS
2568 #define OPTSTYLE 2
2569 #else
2570 #define OPTSTYLE 3
2571 #endif
2572
2573 if (!host_checking && !sender_host_notsocket)
2574 {
2575 #if OPTSTYLE == 1
2576 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2577 struct ip_options *ipopt = store_get(optlen);
2578 #elif OPTSTYLE == 2
2579 struct ip_opts ipoptblock;
2580 struct ip_opts *ipopt = &ipoptblock;
2581 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2582 #else
2583 struct ipoption ipoptblock;
2584 struct ipoption *ipopt = &ipoptblock;
2585 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2586 #endif
2587
2588 /* Occasional genuine failures of getsockopt() have been seen - for
2589 example, "reset by peer". Therefore, just log and give up on this
2590 call, unless the error is ENOPROTOOPT. This error is given by systems
2591 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2592 of writing. So for that error, carry on - we just can't do an IP options
2593 check. */
2594
2595 DEBUG(D_receive) debug_printf("checking for IP options\n");
2596
2597 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2598 &optlen) < 0)
2599 {
2600 if (errno != ENOPROTOOPT)
2601 {
2602 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2603 host_and_ident(FALSE), strerror(errno));
2604 smtp_printf("451 SMTP service not available\r\n", FALSE);
2605 return FALSE;
2606 }
2607 }
2608
2609 /* Deal with any IP options that are set. On the systems I have looked at,
2610 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2611 more logging data than will fit in big_buffer. Nevertheless, after somebody
2612 questioned this code, I've added in some paranoid checking. */
2613
2614 else if (optlen > 0)
2615 {
2616 uschar *p = big_buffer;
2617 uschar *pend = big_buffer + big_buffer_size;
2618 uschar *opt, *adptr;
2619 int optcount;
2620 struct in_addr addr;
2621
2622 #if OPTSTYLE == 1
2623 uschar *optstart = US (ipopt->__data);
2624 #elif OPTSTYLE == 2
2625 uschar *optstart = US (ipopt->ip_opts);
2626 #else
2627 uschar *optstart = US (ipopt->ipopt_list);
2628 #endif
2629
2630 DEBUG(D_receive) debug_printf("IP options exist\n");
2631
2632 Ustrcpy(p, "IP options on incoming call:");
2633 p += Ustrlen(p);
2634
2635 for (opt = optstart; opt != NULL &&
2636 opt < US (ipopt) + optlen;)
2637 {
2638 switch (*opt)
2639 {
2640 case IPOPT_EOL:
2641 opt = NULL;
2642 break;
2643
2644 case IPOPT_NOP:
2645 opt++;
2646 break;
2647
2648 case IPOPT_SSRR:
2649 case IPOPT_LSRR:
2650 if (!string_format(p, pend-p, " %s [@%s",
2651 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2652 #if OPTSTYLE == 1
2653 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2654 #elif OPTSTYLE == 2
2655 inet_ntoa(ipopt->ip_dst)))
2656 #else
2657 inet_ntoa(ipopt->ipopt_dst)))
2658 #endif
2659 {
2660 opt = NULL;
2661 break;
2662 }
2663
2664 p += Ustrlen(p);
2665 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2666 adptr = opt + 3;
2667 while (optcount-- > 0)
2668 {
2669 memcpy(&addr, adptr, sizeof(addr));
2670 if (!string_format(p, pend - p - 1, "%s%s",
2671 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2672 {
2673 opt = NULL;
2674 break;
2675 }
2676 p += Ustrlen(p);
2677 adptr += sizeof(struct in_addr);
2678 }
2679 *p++ = ']';
2680 opt += opt[1];
2681 break;
2682
2683 default:
2684 {
2685 int i;
2686 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2687 Ustrcat(p, "[ ");
2688 p += 2;
2689 for (i = 0; i < opt[1]; i++)
2690 p += sprintf(CS p, "%2.2x ", opt[i]);
2691 *p++ = ']';
2692 }
2693 opt += opt[1];
2694 break;
2695 }
2696 }
2697
2698 *p = 0;
2699 log_write(0, LOG_MAIN, "%s", big_buffer);
2700
2701 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2702
2703 log_write(0, LOG_MAIN|LOG_REJECT,
2704 "connection from %s refused (IP options)", host_and_ident(FALSE));
2705
2706 smtp_printf("554 SMTP service not available\r\n", FALSE);
2707 return FALSE;
2708 }
2709
2710 /* Length of options = 0 => there are no options */
2711
2712 else DEBUG(D_receive) debug_printf("no IP options found\n");
2713 }
2714 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2715
2716 /* Set keep-alive in socket options. The option is on by default. This
2717 setting is an attempt to get rid of some hanging connections that stick in
2718 read() when the remote end (usually a dialup) goes away. */
2719
2720 if (smtp_accept_keepalive && !sender_host_notsocket)
2721 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2722
2723 /* If the current host matches host_lookup, set the name by doing a
2724 reverse lookup. On failure, sender_host_name will be NULL and
2725 host_lookup_failed will be TRUE. This may or may not be serious - optional
2726 checks later. */
2727
2728 if (verify_check_host(&host_lookup) == OK)
2729 {
2730 (void)host_name_lookup();
2731 host_build_sender_fullhost();
2732 }
2733
2734 /* Delay this until we have the full name, if it is looked up. */
2735
2736 set_process_info("handling incoming connection from %s",
2737 host_and_ident(FALSE));
2738
2739 /* Expand smtp_receive_timeout, if needed */
2740
2741 if (smtp_receive_timeout_s)
2742 {
2743 uschar * exp;
2744 if ( !(exp = expand_string(smtp_receive_timeout_s))
2745 || !(*exp)
2746 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2747 )
2748 log_write(0, LOG_MAIN|LOG_PANIC,
2749 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2750 }
2751
2752 /* Test for explicit connection rejection */
2753
2754 if (verify_check_host(&host_reject_connection) == OK)
2755 {
2756 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2757 "from %s (host_reject_connection)", host_and_ident(FALSE));
2758 smtp_printf("554 SMTP service not available\r\n", FALSE);
2759 return FALSE;
2760 }
2761
2762 /* Test with TCP Wrappers if so configured. There is a problem in that
2763 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2764 such as disks dying. In these cases, it is desirable to reject with a 4xx
2765 error instead of a 5xx error. There isn't a "right" way to detect such
2766 problems. The following kludge is used: errno is zeroed before calling
2767 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2768 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2769 not exist). */
2770
2771 #ifdef USE_TCP_WRAPPERS
2772 errno = 0;
2773 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2774 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2775 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2776 expand_string_message);
2777
2778 if (!hosts_ctl(tcp_wrappers_name,
2779 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2780 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2781 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2782 {
2783 if (errno == 0 || errno == ENOENT)
2784 {
2785 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2786 log_write(L_connection_reject,
2787 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2788 "(tcp wrappers)", host_and_ident(FALSE));
2789 smtp_printf("554 SMTP service not available\r\n", FALSE);
2790 }
2791 else
2792 {
2793 int save_errno = errno;
2794 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2795 "errno value %d\n", save_errno);
2796 log_write(L_connection_reject,
2797 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2798 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2799 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2800 }
2801 return FALSE;
2802 }
2803 #endif
2804
2805 /* Check for reserved slots. The value of smtp_accept_count has already been
2806 incremented to include this process. */
2807
2808 if (smtp_accept_max > 0 &&
2809 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2810 {
2811 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2812 {
2813 log_write(L_connection_reject,
2814 LOG_MAIN, "temporarily refused connection from %s: not in "
2815 "reserve list: connected=%d max=%d reserve=%d%s",
2816 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2817 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2818 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2819 "please try again later\r\n", FALSE, smtp_active_hostname);
2820 return FALSE;
2821 }
2822 reserved_host = TRUE;
2823 }
2824
2825 /* If a load level above which only messages from reserved hosts are
2826 accepted is set, check the load. For incoming calls via the daemon, the
2827 check is done in the superior process if there are no reserved hosts, to
2828 save a fork. In all cases, the load average will already be available
2829 in a global variable at this point. */
2830
2831 if (smtp_load_reserve >= 0 &&
2832 load_average > smtp_load_reserve &&
2833 !reserved_host &&
2834 verify_check_host(&smtp_reserve_hosts) != OK)
2835 {
2836 log_write(L_connection_reject,
2837 LOG_MAIN, "temporarily refused connection from %s: not in "
2838 "reserve list and load average = %.2f", host_and_ident(FALSE),
2839 (double)load_average/1000.0);
2840 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2841 smtp_active_hostname);
2842 return FALSE;
2843 }
2844
2845 /* Determine whether unqualified senders or recipients are permitted
2846 for this host. Unfortunately, we have to do this every time, in order to
2847 set the flags so that they can be inspected when considering qualifying
2848 addresses in the headers. For a site that permits no qualification, this
2849 won't take long, however. */
2850
2851 allow_unqualified_sender =
2852 verify_check_host(&sender_unqualified_hosts) == OK;
2853
2854 allow_unqualified_recipient =
2855 verify_check_host(&recipient_unqualified_hosts) == OK;
2856
2857 /* Determine whether HELO/EHLO is required for this host. The requirement
2858 can be hard or soft. */
2859
2860 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2861 if (!helo_required)
2862 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2863
2864 /* Determine whether this hosts is permitted to send syntactic junk
2865 after a HELO or EHLO command. */
2866
2867 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2868 }
2869
2870 /* For batch SMTP input we are now done. */
2871
2872 if (smtp_batched_input) return TRUE;
2873
2874 /* If valid Proxy Protocol source is connecting, set up session.
2875 * Failure will not allow any SMTP function other than QUIT. */
2876
2877 #ifdef SUPPORT_PROXY
2878 proxy_session = FALSE;
2879 proxy_session_failed = FALSE;
2880 if (check_proxy_protocol_host())
2881 setup_proxy_protocol_host();
2882 #endif
2883
2884 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2885 smtps port for use with older style SSL MTAs. */
2886
2887 #ifdef SUPPORT_TLS
2888 if (tls_in.on_connect)
2889 {
2890 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2891 return smtp_log_tls_fail(user_msg);
2892 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2893 }
2894 #endif
2895
2896 /* Run the connect ACL if it exists */
2897
2898 user_msg = NULL;
2899 if (acl_smtp_connect)
2900 {
2901 int rc;
2902 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2903 &log_msg)) != OK)
2904 {
2905 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2906 return FALSE;
2907 }
2908 }
2909
2910 /* Output the initial message for a two-way SMTP connection. It may contain
2911 newlines, which then cause a multi-line response to be given. */
2912
2913 code = US"220"; /* Default status code */
2914 esc = US""; /* Default extended status code */
2915 esclen = 0; /* Length of esc */
2916
2917 if (!user_msg)
2918 {
2919 if (!(s = expand_string(smtp_banner)))
2920 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2921 "failed: %s", smtp_banner, expand_string_message);
2922 }
2923 else
2924 {
2925 int codelen = 3;
2926 s = user_msg;
2927 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2928 if (codelen > 4)
2929 {
2930 esc = code + 4;
2931 esclen = codelen - 4;
2932 }
2933 }
2934
2935 /* Remove any terminating newlines; might as well remove trailing space too */
2936
2937 p = s + Ustrlen(s);
2938 while (p > s && isspace(p[-1])) p--;
2939 *p = 0;
2940
2941 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2942 is all contained in a single IP packet. The original code wrote out the
2943 greeting using several calls to fprint/fputc, and on busy servers this could
2944 cause it to be split over more than one packet - which caused CC:Mail to fall
2945 over when it got the second part of the greeting after sending its first
2946 command. Sigh. To try to avoid this, build the complete greeting message
2947 first, and output it in one fell swoop. This gives a better chance of it
2948 ending up as a single packet. */
2949
2950 ss = string_get(256);
2951
2952 p = s;
2953 do /* At least once, in case we have an empty string */
2954 {
2955 int len;
2956 uschar *linebreak = Ustrchr(p, '\n');
2957 ss = string_catn(ss, code, 3);
2958 if (!linebreak)
2959 {
2960 len = Ustrlen(p);
2961 ss = string_catn(ss, US" ", 1);
2962 }
2963 else
2964 {
2965 len = linebreak - p;
2966 ss = string_catn(ss, US"-", 1);
2967 }
2968 ss = string_catn(ss, esc, esclen);
2969 ss = string_catn(ss, p, len);
2970 ss = string_catn(ss, US"\r\n", 2);
2971 p += len;
2972 if (linebreak) p++;
2973 }
2974 while (*p);
2975
2976 /* Before we write the banner, check that there is no input pending, unless
2977 this synchronisation check is disabled. */
2978
2979 if (!check_sync())
2980 {
2981 unsigned n = smtp_inend - smtp_inptr;
2982 if (n > 32) n = 32;
2983
2984 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2985 "synchronization error (input sent without waiting for greeting): "
2986 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2987 string_printing(string_copyn(smtp_inptr, n)));
2988 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2989 return FALSE;
2990 }
2991
2992 /* Now output the banner */
2993
2994 smtp_printf("%s", FALSE, string_from_gstring(ss));
2995
2996 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2997 handshake arrived. If so we must have managed a TFO. */
2998
2999 #ifdef TCP_FASTOPEN
3000 tfo_in_check();
3001 #endif
3002
3003 return TRUE;
3004 }
3005
3006
3007
3008
3009
3010 /*************************************************
3011 * Handle SMTP syntax and protocol errors *
3012 *************************************************/
3013
3014 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3015 to do so. Then transmit the error response. The return value depends on the
3016 number of syntax and protocol errors in this SMTP session.
3017
3018 Arguments:
3019 type error type, given as a log flag bit
3020 code response code; <= 0 means don't send a response
3021 data data to reflect in the response (can be NULL)
3022 errmess the error message
3023
3024 Returns: -1 limit of syntax/protocol errors NOT exceeded
3025 +1 limit of syntax/protocol errors IS exceeded
3026
3027 These values fit in with the values of the "done" variable in the main
3028 processing loop in smtp_setup_msg(). */
3029
3030 static int
3031 synprot_error(int type, int code, uschar *data, uschar *errmess)
3032 {
3033 int yield = -1;
3034
3035 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3036 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3037 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3038
3039 if (++synprot_error_count > smtp_max_synprot_errors)
3040 {
3041 yield = 1;
3042 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3043 "syntax or protocol errors (last command was \"%s\")",
3044 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3045 }
3046
3047 if (code > 0)
3048 {
3049 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3050 data ? data : US"", data ? US": " : US"", errmess);
3051 if (yield == 1)
3052 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3053 }
3054
3055 return yield;
3056 }
3057
3058
3059
3060
3061 /*************************************************
3062 * Send SMTP response, possibly multiline *
3063 *************************************************/
3064
3065 /* There are, it seems, broken clients out there that cannot handle multiline
3066 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3067 output nothing for non-final calls, and only the first line for anything else.
3068
3069 Arguments:
3070 code SMTP code, may involve extended status codes
3071 codelen length of smtp code; if > 4 there's an ESC
3072 final FALSE if the last line isn't the final line
3073 msg message text, possibly containing newlines
3074
3075 Returns: nothing
3076 */
3077
3078 void
3079 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3080 {
3081 int esclen = 0;
3082 uschar *esc = US"";
3083
3084 if (!final && no_multiline_responses) return;
3085
3086 if (codelen > 4)
3087 {
3088 esc = code + 4;
3089 esclen = codelen - 4;
3090 }
3091
3092 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3093 have had the same. Note: this code is also present in smtp_printf(). It would
3094 be tidier to have it only in one place, but when it was added, it was easier to
3095 do it that way, so as not to have to mess with the code for the RCPT command,
3096 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3097
3098 if (rcpt_in_progress)
3099 {
3100 if (rcpt_smtp_response == NULL)
3101 rcpt_smtp_response = string_copy(msg);
3102 else if (rcpt_smtp_response_same &&
3103 Ustrcmp(rcpt_smtp_response, msg) != 0)
3104 rcpt_smtp_response_same = FALSE;
3105 rcpt_in_progress = FALSE;
3106 }
3107
3108 /* Now output the message, splitting it up into multiple lines if necessary.
3109 We only handle pipelining these responses as far as nonfinal/final groups,
3110 not the whole MAIL/RCPT/DATA response set. */
3111
3112 for (;;)
3113 {
3114 uschar *nl = Ustrchr(msg, '\n');
3115 if (nl == NULL)
3116 {
3117 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3118 return;
3119 }
3120 else if (nl[1] == 0 || no_multiline_responses)
3121 {
3122 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3123 (int)(nl - msg), msg);
3124 return;
3125 }
3126 else
3127 {
3128 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3129 msg = nl + 1;
3130 while (isspace(*msg)) msg++;
3131 }
3132 }
3133 }
3134
3135
3136
3137
3138 /*************************************************
3139 * Parse user SMTP message *
3140 *************************************************/
3141
3142 /* This function allows for user messages overriding the response code details
3143 by providing a suitable response code string at the start of the message
3144 user_msg. Check the message for starting with a response code and optionally an
3145 extended status code. If found, check that the first digit is valid, and if so,
3146 change the code pointer and length to use the replacement. An invalid code
3147 causes a panic log; in this case, if the log messages is the same as the user
3148 message, we must also adjust the value of the log message to show the code that
3149 is actually going to be used (the original one).
3150
3151 This function is global because it is called from receive.c as well as within
3152 this module.
3153
3154 Note that the code length returned includes the terminating whitespace
3155 character, which is always included in the regex match.
3156
3157 Arguments:
3158 code SMTP code, may involve extended status codes
3159 codelen length of smtp code; if > 4 there's an ESC
3160 msg message text
3161 log_msg optional log message, to be adjusted with the new SMTP code
3162 check_valid if true, verify the response code
3163
3164 Returns: nothing
3165 */
3166
3167 void
3168 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3169 BOOL check_valid)
3170 {
3171 int n;
3172 int ovector[3];
3173
3174 if (!msg || !*msg) return;
3175
3176 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3177 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3178
3179 if (check_valid && (*msg)[0] != (*code)[0])
3180 {
3181 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3182 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3183 if (log_msg != NULL && *log_msg == *msg)
3184 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3185 }
3186 else
3187 {
3188 *code = *msg;
3189 *codelen = ovector[1]; /* Includes final space */
3190 }
3191 *msg += ovector[1]; /* Chop the code off the message */
3192 return;
3193 }
3194
3195
3196
3197
3198 /*************************************************
3199 * Handle an ACL failure *
3200 *************************************************/
3201
3202 /* This function is called when acl_check() fails. As well as calls from within
3203 this module, it is called from receive.c for an ACL after DATA. It sorts out
3204 logging the incident, and sends the error response. A message containing
3205 newlines is turned into a multiline SMTP response, but for logging, only the
3206 first line is used.
3207
3208 There's a table of default permanent failure response codes to use in
3209 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3210 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3211 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3212 state, because there are broken clients that try VRFY before RCPT. A 5xx
3213 response should be given only when the address is positively known to be
3214 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3215 no explicit code, but if there is one we let it know best.
3216 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3217
3218 From Exim 4.63, it is possible to override the response code details by
3219 providing a suitable response code string at the start of the message provided
3220 in user_msg. The code's first digit is checked for validity.
3221
3222 Arguments:
3223 where where the ACL was called from
3224 rc the failure code
3225 user_msg a message that can be included in an SMTP response
3226 log_msg a message for logging
3227
3228 Returns: 0 in most cases
3229 2 if the failure code was FAIL_DROP, in which case the
3230 SMTP connection should be dropped (this value fits with the
3231 "done" variable in smtp_setup_msg() below)
3232 */
3233
3234 int
3235 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3236 {
3237 BOOL drop = rc == FAIL_DROP;
3238 int codelen = 3;
3239 uschar *smtp_code;
3240 uschar *lognl;
3241 uschar *sender_info = US"";
3242 uschar *what =
3243 #ifdef WITH_CONTENT_SCAN
3244 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3245 #endif
3246 where == ACL_WHERE_PREDATA ? US"DATA" :
3247 where == ACL_WHERE_DATA ? US"after DATA" :
3248 #ifndef DISABLE_PRDR
3249 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3250 #endif
3251 smtp_cmd_data ?
3252 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3253 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3254
3255 if (drop) rc = FAIL;
3256
3257 /* Set the default SMTP code, and allow a user message to change it. */
3258
3259 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3260 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3261 where != ACL_WHERE_VRFY);
3262
3263 /* We used to have sender_address here; however, there was a bug that was not
3264 updating sender_address after a rewrite during a verify. When this bug was
3265 fixed, sender_address at this point became the rewritten address. I'm not sure
3266 this is what should be logged, so I've changed to logging the unrewritten
3267 address to retain backward compatibility. */
3268
3269 #ifndef WITH_CONTENT_SCAN
3270 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3271 #else
3272 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3273 #endif
3274 {
3275 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3276 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3277 sender_host_authenticated ? US" A=" : US"",
3278 sender_host_authenticated ? sender_host_authenticated : US"",
3279 sender_host_authenticated && authenticated_id ? US":" : US"",
3280 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3281 );
3282 }
3283
3284 /* If there's been a sender verification failure with a specific message, and
3285 we have not sent a response about it yet, do so now, as a preliminary line for
3286 failures, but not defers. However, always log it for defer, and log it for fail
3287 unless the sender_verify_fail log selector has been turned off. */
3288
3289 if (sender_verified_failed &&
3290 !testflag(sender_verified_failed, af_sverify_told))
3291 {
3292 BOOL save_rcpt_in_progress = rcpt_in_progress;
3293 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3294
3295 setflag(sender_verified_failed, af_sverify_told);
3296
3297 if (rc != FAIL || LOGGING(sender_verify_fail))
3298 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3299 host_and_ident(TRUE),
3300 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3301 sender_verified_failed->address,
3302 (sender_verified_failed->message == NULL)? US"" :
3303 string_sprintf(": %s", sender_verified_failed->message));
3304
3305 if (rc == FAIL && sender_verified_failed->user_message)
3306 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3307 testflag(sender_verified_failed, af_verify_pmfail)?
3308 "Postmaster verification failed while checking <%s>\n%s\n"
3309 "Several RFCs state that you are required to have a postmaster\n"
3310 "mailbox for each mail domain. This host does not accept mail\n"
3311 "from domains whose servers reject the postmaster address."
3312 :
3313 testflag(sender_verified_failed, af_verify_nsfail)?
3314 "Callback setup failed while verifying <%s>\n%s\n"
3315 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3316 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3317 "RFC requirements, and stops you from receiving standard bounce\n"
3318 "messages. This host does not accept mail from domains whose servers\n"
3319 "refuse bounces."
3320 :
3321 "Verification failed for <%s>\n%s",
3322 sender_verified_failed->address,
3323 sender_verified_failed->user_message));
3324
3325 rcpt_in_progress = save_rcpt_in_progress;
3326 }
3327
3328 /* Sort out text for logging */
3329
3330 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3331 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3332
3333 /* Send permanent failure response to the command, but the code used isn't
3334 always a 5xx one - see comments at the start of this function. If the original
3335 rc was FAIL_DROP we drop the connection and yield 2. */
3336
3337 if (rc == FAIL)
3338 smtp_respond(smtp_code, codelen, TRUE,
3339 user_msg ? user_msg : US"Administrative prohibition");
3340
3341 /* Send temporary failure response to the command. Don't give any details,
3342 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3343 verb, and for a header verify when smtp_return_error_details is set.
3344
3345 This conditional logic is all somewhat of a mess because of the odd
3346 interactions between temp_details and return_error_details. One day it should
3347 be re-implemented in a tidier fashion. */
3348
3349 else
3350 if (acl_temp_details && user_msg)
3351 {
3352 if ( smtp_return_error_details
3353 && sender_verified_failed
3354 && sender_verified_failed->message
3355 )
3356 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3357
3358 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3359 }
3360 else
3361 smtp_respond(smtp_code, codelen, TRUE,
3362 US"Temporary local problem - please try later");
3363
3364 /* Log the incident to the logs that are specified by log_reject_target
3365 (default main, reject). This can be empty to suppress logging of rejections. If
3366 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3367 is closing if required and return 2. */
3368
3369 if (log_reject_target != 0)
3370 {
3371 #ifdef SUPPORT_TLS
3372 gstring * g = s_tlslog(NULL);
3373 uschar * tls = string_from_gstring(g);
3374 if (!tls) tls = US"";
3375 #else
3376 uschar * tls = US"";
3377 #endif
3378 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3379 log_reject_target, "%s%s%s %s%srejected %s%s",
3380 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3381 host_and_ident(TRUE),
3382 tls,
3383 sender_info,
3384 rc == FAIL ? US"" : US"temporarily ",
3385 what, log_msg);
3386 }
3387
3388 if (!drop) return 0;
3389
3390 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3391 smtp_get_connection_info());
3392
3393 /* Run the not-quit ACL, but without any custom messages. This should not be a
3394 problem, because we get here only if some other ACL has issued "drop", and
3395 in that case, *its* custom messages will have been used above. */
3396
3397 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3398 return 2;
3399 }
3400
3401
3402
3403
3404 /*************************************************
3405 * Handle SMTP exit when QUIT is not given *
3406 *************************************************/
3407
3408 /* This function provides a logging/statistics hook for when an SMTP connection
3409 is dropped on the floor or the other end goes away. It's a global function
3410 because it's called from receive.c as well as this module. As well as running
3411 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3412 response, either with a custom message from the ACL, or using a default. There
3413 is one case, however, when no message is output - after "drop". In that case,
3414 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3415 passed to this function.
3416
3417 In case things go wrong while processing this function, causing an error that
3418 may re-enter this function, there is a recursion check.
3419
3420 Arguments:
3421 reason What $smtp_notquit_reason will be set to in the ACL;
3422 if NULL, the ACL is not run
3423 code The error code to return as part of the response
3424 defaultrespond The default message if there's no user_msg
3425
3426 Returns: Nothing
3427 */
3428
3429 void
3430 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3431 {
3432 int rc;
3433 uschar *user_msg = NULL;
3434 uschar *log_msg = NULL;
3435
3436 /* Check for recursive acll */
3437
3438 if (smtp_exit_function_called)
3439 {
3440 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3441 reason);
3442 return;
3443 }
3444 smtp_exit_function_called = TRUE;
3445
3446 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3447
3448 if (acl_smtp_notquit && reason)
3449 {
3450 smtp_notquit_reason = reason;
3451 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3452 &log_msg)) == ERROR)
3453 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3454 log_msg);
3455 }
3456
3457 /* Write an SMTP response if we are expected to give one. As the default
3458 responses are all internal, they should always fit in the buffer, but code a
3459 warning, just in case. Note that string_vformat() still leaves a complete
3460 string, even if it is incomplete. */
3461
3462 if (code && defaultrespond)
3463 {
3464 if (user_msg)
3465 smtp_respond(code, 3, TRUE, user_msg);
3466 else
3467 {
3468 uschar buffer[128];
3469 va_list ap;
3470 va_start(ap, defaultrespond);
3471 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3472 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3473 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3474 va_end(ap);
3475 }
3476 mac_smtp_fflush();
3477 }
3478 }
3479
3480
3481
3482
3483 /*************************************************
3484 * Verify HELO argument *
3485 *************************************************/
3486
3487 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3488 matched. It is also called from ACL processing if verify = helo is used and
3489 verification was not previously tried (i.e. helo_try_verify_hosts was not
3490 matched). The result of its processing is to set helo_verified and
3491 helo_verify_failed. These variables should both be FALSE for this function to
3492 be called.
3493
3494 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3495 for IPv6 ::ffff: literals.
3496
3497 Argument: none
3498 Returns: TRUE if testing was completed;
3499 FALSE on a temporary failure
3500 */
3501
3502 BOOL
3503 smtp_verify_helo(void)
3504 {
3505 BOOL yield = TRUE;
3506
3507 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3508 sender_helo_name);
3509
3510 if (sender_helo_name == NULL)
3511 {
3512 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3513 }
3514
3515 /* Deal with the case of -bs without an IP address */
3516
3517 else if (sender_host_address == NULL)
3518 {
3519 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3520 helo_verified = TRUE;
3521 }
3522
3523 /* Deal with the more common case when there is a sending IP address */