FreeBSD: better support for TFO
[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 struct {
135 BOOL auth_advertised :1;
136 #ifndef DISABLE_TLS
137 BOOL tls_advertised :1;
138 #endif
139 BOOL dsn_advertised :1;
140 BOOL esmtp :1;
141 BOOL helo_required :1;
142 BOOL helo_verify :1;
143 BOOL helo_seen :1;
144 BOOL helo_accept_junk :1;
145 #ifndef DISABLE_PIPE_CONNECT
146 BOOL pipe_connect_acceptable :1;
147 #endif
148 BOOL rcpt_smtp_response_same :1;
149 BOOL rcpt_in_progress :1;
150 BOOL smtp_exit_function_called :1;
151 #ifdef SUPPORT_I18N
152 BOOL smtputf8_advertised :1;
153 #endif
154 } fl = {
155 .helo_required = FALSE,
156 .helo_verify = FALSE,
157 .smtp_exit_function_called = FALSE,
158 };
159
160 static auth_instance *authenticated_by;
161 static int count_nonmail;
162 static int nonmail_command_count;
163 static int synprot_error_count;
164 static int unknown_command_count;
165 static int sync_cmd_limit;
166 static int smtp_write_error = 0;
167
168 static uschar *rcpt_smtp_response;
169 static uschar *smtp_data_buffer;
170 static uschar *smtp_cmd_data;
171
172 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
173 final fields of all except AUTH are forced TRUE at the start of a new message
174 setup, to allow one of each between messages that is not counted as a nonmail
175 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
176 allow a new EHLO after starting up TLS.
177
178 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
179 counted. However, the flag is changed when AUTH is received, so that multiple
180 failing AUTHs will eventually hit the limit. After a successful AUTH, another
181 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
182 forced TRUE, to allow for the re-authentication that can happen at that point.
183
184 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
185 count of non-mail commands and possibly provoke an error.
186
187 tls_auth is a pseudo-command, never expected in input. It is activated
188 on TLS startup and looks for a tls authenticator. */
189
190 static smtp_cmd_list cmd_list[] = {
191 /* name len cmd has_arg is_mail_cmd */
192
193 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
194 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
195 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
196 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
197 #ifndef DISABLE_TLS
198 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
199 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
200 #endif
201
202 /* If you change anything above here, also fix the definitions below. */
203
204 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
205 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
206 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
207 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
208 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
209 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
210 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
211 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
212 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
213 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
214 };
215
216 static smtp_cmd_list *cmd_list_end =
217 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
218
219 #define CMD_LIST_RSET 0
220 #define CMD_LIST_HELO 1
221 #define CMD_LIST_EHLO 2
222 #define CMD_LIST_AUTH 3
223 #define CMD_LIST_STARTTLS 4
224 #define CMD_LIST_TLS_AUTH 5
225
226 /* This list of names is used for performing the smtp_no_mail logging action.
227 It must be kept in step with the SCH_xxx enumerations. */
228
229 static uschar *smtp_names[] =
230 {
231 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
232 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
233 US"STARTTLS", US"VRFY" };
234
235 static uschar *protocols_local[] = {
236 US"local-smtp", /* HELO */
237 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
238 US"local-esmtp", /* EHLO */
239 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
240 US"local-esmtpa", /* EHLO->AUTH */
241 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
242 };
243 static uschar *protocols[] = {
244 US"smtp", /* HELO */
245 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
246 US"esmtp", /* EHLO */
247 US"esmtps", /* EHLO->STARTTLS->EHLO */
248 US"esmtpa", /* EHLO->AUTH */
249 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
250 };
251
252 #define pnormal 0
253 #define pextend 2
254 #define pcrpted 1 /* added to pextend or pnormal */
255 #define pauthed 2 /* added to pextend */
256
257 /* Sanity check and validate optional args to MAIL FROM: envelope */
258 enum {
259 ENV_MAIL_OPT_NULL,
260 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
261 #ifndef DISABLE_PRDR
262 ENV_MAIL_OPT_PRDR,
263 #endif
264 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
265 #ifdef SUPPORT_I18N
266 ENV_MAIL_OPT_UTF8,
267 #endif
268 };
269 typedef struct {
270 uschar * name; /* option requested during MAIL cmd */
271 int value; /* enum type */
272 BOOL need_value; /* TRUE requires value (name=value pair format)
273 FALSE is a singleton */
274 } env_mail_type_t;
275 static env_mail_type_t env_mail_type_list[] = {
276 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
277 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
278 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
279 #ifndef DISABLE_PRDR
280 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
281 #endif
282 { US"RET", ENV_MAIL_OPT_RET, TRUE },
283 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
284 #ifdef SUPPORT_I18N
285 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
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 #ifndef DISABLE_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 || f.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 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
392 return FALSE;
393
394 if (wouldblock_reading()) return FALSE;
395 f.smtp_in_pipelining_used = TRUE;
396 return TRUE;
397 }
398
399
400 #ifndef DISABLE_PIPE_CONNECT
401 static BOOL
402 pipeline_connect_sends(void)
403 {
404 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
405 return FALSE;
406
407 if (wouldblock_reading()) return FALSE;
408 f.smtp_in_early_pipe_used = TRUE;
409 return TRUE;
410 }
411 #endif
412
413 /*************************************************
414 * Log incomplete transactions *
415 *************************************************/
416
417 /* This function is called after a transaction has been aborted by RSET, QUIT,
418 connection drops or other errors. It logs the envelope information received
419 so far in order to preserve address verification attempts.
420
421 Argument: string to indicate what aborted the transaction
422 Returns: nothing
423 */
424
425 static void
426 incomplete_transaction_log(uschar *what)
427 {
428 if (!sender_address /* No transaction in progress */
429 || !LOGGING(smtp_incomplete_transaction))
430 return;
431
432 /* Build list of recipients for logging */
433
434 if (recipients_count > 0)
435 {
436 raw_recipients = store_get(recipients_count * sizeof(uschar *), FALSE);
437 for (int i = 0; i < recipients_count; i++)
438 raw_recipients[i] = recipients_list[i].address;
439 raw_recipients_count = recipients_count;
440 }
441
442 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
443 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
444 }
445
446
447
448
449 void
450 smtp_command_timeout_exit(void)
451 {
452 log_write(L_lost_incoming_connection,
453 LOG_MAIN, "SMTP command timeout on%s connection from %s",
454 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
455 if (smtp_batched_input)
456 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
457 smtp_notquit_exit(US"command-timeout", US"421",
458 US"%s: SMTP command timeout - closing connection",
459 smtp_active_hostname);
460 exim_exit(EXIT_FAILURE, US"receiving");
461 }
462
463 void
464 smtp_command_sigterm_exit(void)
465 {
466 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
467 if (smtp_batched_input)
468 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
469 smtp_notquit_exit(US"signal-exit", US"421",
470 US"%s: Service not available - closing connection", smtp_active_hostname);
471 exim_exit(EXIT_FAILURE, US"receiving");
472 }
473
474 void
475 smtp_data_timeout_exit(void)
476 {
477 log_write(L_lost_incoming_connection,
478 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
479 sender_fullhost ? sender_fullhost : US"local process", sender_address);
480 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
481 /* Does not return */
482 }
483
484 void
485 smtp_data_sigint_exit(void)
486 {
487 log_write(0, LOG_MAIN, "%s closed after %s",
488 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
489 receive_bomb_out(US"signal-exit",
490 US"Service not available - SIGTERM or SIGINT received");
491 /* Does not return */
492 }
493
494
495
496 /* Refill the buffer, and notify DKIM verification code.
497 Return false for error or EOF.
498 */
499
500 static BOOL
501 smtp_refill(unsigned lim)
502 {
503 int rc, save_errno;
504 if (!smtp_out) return FALSE;
505 fflush(smtp_out);
506 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
507
508 /* Limit amount read, so non-message data is not fed to DKIM.
509 Take care to not touch the safety NUL at the end of the buffer. */
510
511 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
512 save_errno = errno;
513 if (smtp_receive_timeout > 0) ALARM_CLR(0);
514 if (rc <= 0)
515 {
516 /* Must put the error text in fixed store, because this might be during
517 header reading, where it releases unused store above the header. */
518 if (rc < 0)
519 {
520 if (had_command_timeout) /* set by signal handler */
521 smtp_command_timeout_exit(); /* does not return */
522 if (had_command_sigterm)
523 smtp_command_sigterm_exit();
524 if (had_data_timeout)
525 smtp_data_timeout_exit();
526 if (had_data_sigint)
527 smtp_data_sigint_exit();
528
529 smtp_had_error = save_errno;
530 smtp_read_error = string_copy_perm(
531 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
532 }
533 else
534 smtp_had_eof = 1;
535 return FALSE;
536 }
537 #ifndef DISABLE_DKIM
538 dkim_exim_verify_feed(smtp_inbuffer, rc);
539 #endif
540 smtp_inend = smtp_inbuffer + rc;
541 smtp_inptr = smtp_inbuffer;
542 return TRUE;
543 }
544
545 /*************************************************
546 * SMTP version of getc() *
547 *************************************************/
548
549 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
550 it flushes the output, and refills the buffer, with a timeout. The signal
551 handler is set appropriately by the calling function. This function is not used
552 after a connection has negotiated itself into an TLS/SSL state.
553
554 Arguments: lim Maximum amount to read/buffer
555 Returns: the next character or EOF
556 */
557
558 int
559 smtp_getc(unsigned lim)
560 {
561 if (smtp_inptr >= smtp_inend)
562 if (!smtp_refill(lim))
563 return EOF;
564 return *smtp_inptr++;
565 }
566
567 uschar *
568 smtp_getbuf(unsigned * len)
569 {
570 unsigned size;
571 uschar * buf;
572
573 if (smtp_inptr >= smtp_inend)
574 if (!smtp_refill(*len))
575 { *len = 0; return NULL; }
576
577 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
578 buf = smtp_inptr;
579 smtp_inptr += size;
580 *len = size;
581 return buf;
582 }
583
584 void
585 smtp_get_cache(void)
586 {
587 #ifndef DISABLE_DKIM
588 int n = smtp_inend - smtp_inptr;
589 if (n > 0)
590 dkim_exim_verify_feed(smtp_inptr, n);
591 #endif
592 }
593
594
595 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
596 previous BDAT chunk and getting new ones when we run out. Uses the
597 underlying smtp_getc or tls_getc both for that and for getting the
598 (buffered) data byte. EOD signals (an expected) no further data.
599 ERR signals a protocol error, and EOF a closed input stream.
600
601 Called from read_bdat_smtp() in receive.c for the message body, but also
602 by the headers read loop in receive_msg(); manipulates chunking_state
603 to handle the BDAT command/response.
604 Placed here due to the correlation with the above smtp_getc(), which it wraps,
605 and also by the need to do smtp command/response handling.
606
607 Arguments: lim (ignored)
608 Returns: the next character or ERR, EOD or EOF
609 */
610
611 int
612 bdat_getc(unsigned lim)
613 {
614 uschar * user_msg = NULL;
615 uschar * log_msg;
616
617 for(;;)
618 {
619 #ifndef DISABLE_DKIM
620 unsigned dkim_save;
621 #endif
622
623 if (chunking_data_left > 0)
624 return lwr_receive_getc(chunking_data_left--);
625
626 receive_getc = lwr_receive_getc;
627 receive_getbuf = lwr_receive_getbuf;
628 receive_ungetc = lwr_receive_ungetc;
629 #ifndef DISABLE_DKIM
630 dkim_save = dkim_collect_input;
631 dkim_collect_input = 0;
632 #endif
633
634 /* Unless PIPELINING was offered, there should be no next command
635 until after we ack that chunk */
636
637 if (!f.smtp_in_pipelining_advertised && !check_sync())
638 {
639 unsigned n = smtp_inend - smtp_inptr;
640 if (n > 32) n = 32;
641
642 incomplete_transaction_log(US"sync failure");
643 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
644 "(next input sent too soon: pipelining was not advertised): "
645 "rejected \"%s\" %s next input=\"%s\"%s",
646 smtp_cmd_buffer, host_and_ident(TRUE),
647 string_printing(string_copyn(smtp_inptr, n)),
648 smtp_inend - smtp_inptr > n ? "..." : "");
649 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
650 US"SMTP synchronization error");
651 goto repeat_until_rset;
652 }
653
654 /* If not the last, ack the received chunk. The last response is delayed
655 until after the data ACL decides on it */
656
657 if (chunking_state == CHUNKING_LAST)
658 {
659 #ifndef DISABLE_DKIM
660 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
661 #endif
662 return EOD;
663 }
664
665 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
666 chunking_state = CHUNKING_OFFERED;
667 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
668
669 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
670 QUIT, RSET or NOOP but handling them seems obvious */
671
672 next_cmd:
673 switch(smtp_read_command(TRUE, 1))
674 {
675 default:
676 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
677 US"only BDAT permissible after non-LAST BDAT");
678
679 repeat_until_rset:
680 switch(smtp_read_command(TRUE, 1))
681 {
682 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
683 case EOF_CMD: return EOF;
684 case RSET_CMD: smtp_rset_handler(); return ERR;
685 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
686 US"only RSET accepted now") > 0)
687 return EOF;
688 goto repeat_until_rset;
689 }
690
691 case QUIT_CMD:
692 smtp_quit_handler(&user_msg, &log_msg);
693 /*FALLTHROUGH*/
694 case EOF_CMD:
695 return EOF;
696
697 case RSET_CMD:
698 smtp_rset_handler();
699 return ERR;
700
701 case NOOP_CMD:
702 HAD(SCH_NOOP);
703 smtp_printf("250 OK\r\n", FALSE);
704 goto next_cmd;
705
706 case BDAT_CMD:
707 {
708 int n;
709
710 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
711 {
712 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
713 US"missing size for BDAT command");
714 return ERR;
715 }
716 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
717 ? CHUNKING_LAST : CHUNKING_ACTIVE;
718 chunking_data_left = chunking_datasize;
719 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
720 (int)chunking_state, chunking_data_left);
721
722 if (chunking_datasize == 0)
723 if (chunking_state == CHUNKING_LAST)
724 return EOD;
725 else
726 {
727 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
728 US"zero size for BDAT command");
729 goto repeat_until_rset;
730 }
731
732 receive_getc = bdat_getc;
733 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
734 receive_ungetc = bdat_ungetc;
735 #ifndef DISABLE_DKIM
736 dkim_collect_input = dkim_save;
737 #endif
738 break; /* to top of main loop */
739 }
740 }
741 }
742 }
743
744 uschar *
745 bdat_getbuf(unsigned * len)
746 {
747 uschar * buf;
748
749 if (chunking_data_left <= 0)
750 { *len = 0; return NULL; }
751
752 if (*len > chunking_data_left) *len = chunking_data_left;
753 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
754 chunking_data_left -= *len;
755 return buf;
756 }
757
758 void
759 bdat_flush_data(void)
760 {
761 while (chunking_data_left)
762 {
763 unsigned n = chunking_data_left;
764 if (!bdat_getbuf(&n)) break;
765 }
766
767 receive_getc = lwr_receive_getc;
768 receive_getbuf = lwr_receive_getbuf;
769 receive_ungetc = lwr_receive_ungetc;
770
771 if (chunking_state != CHUNKING_LAST)
772 {
773 chunking_state = CHUNKING_OFFERED;
774 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
775 }
776 }
777
778
779
780
781 /*************************************************
782 * SMTP version of ungetc() *
783 *************************************************/
784
785 /* Puts a character back in the input buffer. Only ever
786 called once.
787
788 Arguments:
789 ch the character
790
791 Returns: the character
792 */
793
794 int
795 smtp_ungetc(int ch)
796 {
797 *--smtp_inptr = ch;
798 return ch;
799 }
800
801
802 int
803 bdat_ungetc(int ch)
804 {
805 chunking_data_left++;
806 return lwr_receive_ungetc(ch);
807 }
808
809
810
811 /*************************************************
812 * SMTP version of feof() *
813 *************************************************/
814
815 /* Tests for a previous EOF
816
817 Arguments: none
818 Returns: non-zero if the eof flag is set
819 */
820
821 int
822 smtp_feof(void)
823 {
824 return smtp_had_eof;
825 }
826
827
828
829
830 /*************************************************
831 * SMTP version of ferror() *
832 *************************************************/
833
834 /* Tests for a previous read error, and returns with errno
835 restored to what it was when the error was detected.
836
837 Arguments: none
838 Returns: non-zero if the error flag is set
839 */
840
841 int
842 smtp_ferror(void)
843 {
844 errno = smtp_had_error;
845 return smtp_had_error;
846 }
847
848
849
850 /*************************************************
851 * Test for characters in the SMTP buffer *
852 *************************************************/
853
854 /* Used at the end of a message
855
856 Arguments: none
857 Returns: TRUE/FALSE
858 */
859
860 BOOL
861 smtp_buffered(void)
862 {
863 return smtp_inptr < smtp_inend;
864 }
865
866
867
868 /*************************************************
869 * Write formatted string to SMTP channel *
870 *************************************************/
871
872 /* This is a separate function so that we don't have to repeat everything for
873 TLS support or debugging. It is global so that the daemon and the
874 authentication functions can use it. It does not return any error indication,
875 because major problems such as dropped connections won't show up till an output
876 flush for non-TLS connections. The smtp_fflush() function is available for
877 checking that: for convenience, TLS output errors are remembered here so that
878 they are also picked up later by smtp_fflush().
879
880 Arguments:
881 format format string
882 more further data expected
883 ... optional arguments
884
885 Returns: nothing
886 */
887
888 void
889 smtp_printf(const char *format, BOOL more, ...)
890 {
891 va_list ap;
892
893 va_start(ap, more);
894 smtp_vprintf(format, more, ap);
895 va_end(ap);
896 }
897
898 /* This is split off so that verify.c:respond_printf() can, in effect, call
899 smtp_printf(), bearing in mind that in C a vararg function can't directly
900 call another vararg function, only a function which accepts a va_list. */
901 /*XXX consider passing caller-info in, for string_vformat-onward */
902
903 void
904 smtp_vprintf(const char *format, BOOL more, va_list ap)
905 {
906 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
907 BOOL yield;
908
909 /* Use taint-unchecked routines for writing into big_buffer, trusting
910 that we'll never expand it. */
911
912 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
913 string_from_gstring(&gs);
914
915 DEBUG(D_receive)
916 {
917 uschar *msg_copy, *cr, *end;
918 msg_copy = string_copy(gs.s);
919 end = msg_copy + gs.ptr;
920 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
921 memmove(cr, cr + 1, (end--) - cr);
922 debug_printf("SMTP>> %s", msg_copy);
923 }
924
925 if (!yield)
926 {
927 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
928 smtp_closedown(US"Unexpected error");
929 exim_exit(EXIT_FAILURE, NULL);
930 }
931
932 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
933 have had the same. Note: this code is also present in smtp_respond(). It would
934 be tidier to have it only in one place, but when it was added, it was easier to
935 do it that way, so as not to have to mess with the code for the RCPT command,
936 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
937
938 if (fl.rcpt_in_progress)
939 {
940 if (rcpt_smtp_response == NULL)
941 rcpt_smtp_response = string_copy(big_buffer);
942 else if (fl.rcpt_smtp_response_same &&
943 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
944 fl.rcpt_smtp_response_same = FALSE;
945 fl.rcpt_in_progress = FALSE;
946 }
947
948 /* Now write the string */
949
950 if (
951 #ifndef DISABLE_TLS
952 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
953 #endif
954 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
955 )
956 smtp_write_error = -1;
957 }
958
959
960
961 /*************************************************
962 * Flush SMTP out and check for error *
963 *************************************************/
964
965 /* This function isn't currently used within Exim (it detects errors when it
966 tries to read the next SMTP input), but is available for use in local_scan().
967 It flushes the output and checks for errors.
968
969 Arguments: none
970 Returns: 0 for no error; -1 after an error
971 */
972
973 int
974 smtp_fflush(void)
975 {
976 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
977
978 if (
979 #ifndef DISABLE_TLS
980 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
981 #endif
982 (fflush(smtp_out) != 0)
983 )
984 smtp_write_error = -1;
985
986 return smtp_write_error;
987 }
988
989
990
991 /*************************************************
992 * SMTP command read timeout *
993 *************************************************/
994
995 /* Signal handler for timing out incoming SMTP commands. This attempts to
996 finish off tidily.
997
998 Argument: signal number (SIGALRM)
999 Returns: nothing
1000 */
1001
1002 static void
1003 command_timeout_handler(int sig)
1004 {
1005 had_command_timeout = sig;
1006 }
1007
1008
1009
1010 /*************************************************
1011 * SIGTERM received *
1012 *************************************************/
1013
1014 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1015
1016 Argument: signal number (SIGTERM)
1017 Returns: nothing
1018 */
1019
1020 static void
1021 command_sigterm_handler(int sig)
1022 {
1023 had_command_sigterm = sig;
1024 }
1025
1026
1027
1028
1029 #ifdef SUPPORT_PROXY
1030 /*************************************************
1031 * Restore socket timeout to previous value *
1032 *************************************************/
1033 /* If the previous value was successfully retrieved, restore
1034 it before returning control to the non-proxy routines
1035
1036 Arguments: fd - File descriptor for input
1037 get_ok - Successfully retrieved previous values
1038 tvtmp - Time struct with previous values
1039 vslen - Length of time struct
1040 Returns: none
1041 */
1042 static void
1043 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1044 {
1045 if (get_ok == 0)
1046 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1047 }
1048
1049 /*************************************************
1050 * Check if host is required proxy host *
1051 *************************************************/
1052 /* The function determines if inbound host will be a regular smtp host
1053 or if it is configured that it must use Proxy Protocol. A local
1054 connection cannot.
1055
1056 Arguments: none
1057 Returns: bool
1058 */
1059
1060 static BOOL
1061 check_proxy_protocol_host()
1062 {
1063 int rc;
1064
1065 if ( sender_host_address
1066 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1067 sender_host_address, NULL)) == OK)
1068 {
1069 DEBUG(D_receive)
1070 debug_printf("Detected proxy protocol configured host\n");
1071 proxy_session = TRUE;
1072 }
1073 return proxy_session;
1074 }
1075
1076
1077 /*************************************************
1078 * Read data until newline or end of buffer *
1079 *************************************************/
1080 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1081 read an entire buffer and assume there will be nothing past a proxy protocol
1082 header. Our approach normally is to use stdio, but again that relies upon
1083 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1084 reading _nothing_ before client TLS handshake. So we don't want to use the
1085 usual buffering reads which may read enough to block TLS starting.
1086
1087 So unfortunately we're down to "read one byte at a time, with a syscall each,
1088 and expect a little overhead", for all proxy-opened connections which are v1,
1089 just to handle the TLS-on-connect case. Since SSL functions wrap the
1090 underlying fd, we can't assume that we can feed them any already-read content.
1091
1092 We need to know where to read to, the max capacity, and we'll read until we
1093 get a CR and one more character. Let the caller scream if it's CR+!LF.
1094
1095 Return the amount read.
1096 */
1097
1098 static int
1099 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1100 {
1101 uschar *to = base + already;
1102 uschar *cr;
1103 int have = 0;
1104 int ret;
1105 int last = 0;
1106
1107 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1108 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1109
1110 cr = memchr(base, '\r', already);
1111 if (cr != NULL)
1112 {
1113 if ((cr - base) < already - 1)
1114 {
1115 /* \r and presumed \n already within what we have; probably not
1116 actually proxy protocol, but abort cleanly. */
1117 return 0;
1118 }
1119 /* \r is last character read, just need one more. */
1120 last = 1;
1121 }
1122
1123 while (capacity > 0)
1124 {
1125 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1126 if (ret == -1)
1127 return -1;
1128 have++;
1129 if (last)
1130 return have;
1131 if (*to == '\r')
1132 last = 1;
1133 capacity--;
1134 to++;
1135 }
1136
1137 /* reached end without having room for a final newline, abort */
1138 errno = EOVERFLOW;
1139 return -1;
1140 }
1141
1142 /*************************************************
1143 * Setup host for proxy protocol *
1144 *************************************************/
1145 /* The function configures the connection based on a header from the
1146 inbound host to use Proxy Protocol. The specification is very exact
1147 so exit with an error if do not find the exact required pieces. This
1148 includes an incorrect number of spaces separating args.
1149
1150 Arguments: none
1151 Returns: Boolean success
1152 */
1153
1154 static void
1155 setup_proxy_protocol_host()
1156 {
1157 union {
1158 struct {
1159 uschar line[108];
1160 } v1;
1161 struct {
1162 uschar sig[12];
1163 uint8_t ver_cmd;
1164 uint8_t fam;
1165 uint16_t len;
1166 union {
1167 struct { /* TCP/UDP over IPv4, len = 12 */
1168 uint32_t src_addr;
1169 uint32_t dst_addr;
1170 uint16_t src_port;
1171 uint16_t dst_port;
1172 } ip4;
1173 struct { /* TCP/UDP over IPv6, len = 36 */
1174 uint8_t src_addr[16];
1175 uint8_t dst_addr[16];
1176 uint16_t src_port;
1177 uint16_t dst_port;
1178 } ip6;
1179 struct { /* AF_UNIX sockets, len = 216 */
1180 uschar src_addr[108];
1181 uschar dst_addr[108];
1182 } unx;
1183 } addr;
1184 } v2;
1185 } hdr;
1186
1187 /* Temp variables used in PPv2 address:port parsing */
1188 uint16_t tmpport;
1189 char tmpip[INET_ADDRSTRLEN];
1190 struct sockaddr_in tmpaddr;
1191 char tmpip6[INET6_ADDRSTRLEN];
1192 struct sockaddr_in6 tmpaddr6;
1193
1194 /* We can't read "all data until end" because while SMTP is
1195 server-speaks-first, the TLS handshake is client-speaks-first, so for
1196 TLS-on-connect ports the proxy protocol header will usually be immediately
1197 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1198 reinject data for reading by those. So instead we first read "enough to be
1199 safely read within the header, and figure out how much more to read".
1200 For v1 we will later read to the end-of-line, for v2 we will read based upon
1201 the stated length.
1202
1203 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1204 data is needed total. For v1, where the line looks like:
1205 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1206
1207 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1208 We seem to support that. So, if we read 14 octets then we can tell if we're
1209 v2 or v1. If we're v1, we can continue reading as normal.
1210
1211 If we're v2, we can't slurp up the entire header. We need the length in the
1212 15th & 16th octets, then to read everything after that.
1213
1214 So to safely handle v1 and v2, with client-sent-first supported correctly,
1215 we have to do a minimum of 3 read calls, not 1. Eww.
1216 */
1217
1218 #define PROXY_INITIAL_READ 14
1219 #define PROXY_V2_HEADER_SIZE 16
1220 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1221 # error Code bug in sizes of data to read for proxy usage
1222 #endif
1223
1224 int get_ok = 0;
1225 int size, ret;
1226 int fd = fileno(smtp_in);
1227 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1228 uschar * iptype; /* To display debug info */
1229 struct timeval tv;
1230 struct timeval tvtmp;
1231 socklen_t vslen = sizeof(struct timeval);
1232 BOOL yield = FALSE;
1233
1234 /* Save current socket timeout values */
1235 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1236
1237 /* Proxy Protocol host must send header within a short time
1238 (default 3 seconds) or it's considered invalid */
1239 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1240 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1241 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1242 goto bad;
1243
1244 do
1245 {
1246 /* The inbound host was declared to be a Proxy Protocol host, so
1247 don't do a PEEK into the data, actually slurp up enough to be
1248 "safe". Can't take it all because TLS-on-connect clients follow
1249 immediately with TLS handshake. */
1250 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1251 }
1252 while (ret == -1 && errno == EINTR);
1253
1254 if (ret == -1)
1255 goto proxyfail;
1256
1257 /* For v2, handle reading the length, and then the rest. */
1258 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1259 {
1260 int retmore;
1261 uint8_t ver;
1262
1263 /* First get the length fields. */
1264 do
1265 {
1266 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1267 } while (retmore == -1 && errno == EINTR);
1268 if (retmore == -1)
1269 goto proxyfail;
1270 ret += retmore;
1271
1272 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1273
1274 /* May 2014: haproxy combined the version and command into one byte to
1275 allow two full bytes for the length field in order to proxy SSL
1276 connections. SSL Proxy is not supported in this version of Exim, but
1277 must still separate values here. */
1278
1279 if (ver != 0x02)
1280 {
1281 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1282 goto proxyfail;
1283 }
1284
1285 /* The v2 header will always be 16 bytes per the spec. */
1286 size = 16 + ntohs(hdr.v2.len);
1287 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1288 size, (int)sizeof(hdr));
1289
1290 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1291 amount that we need. Double-check that the size is not unreasonable, then
1292 get the rest. */
1293 if (size > sizeof(hdr))
1294 {
1295 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1296 goto proxyfail;
1297 }
1298
1299 do
1300 {
1301 do
1302 {
1303 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1304 } while (retmore == -1 && errno == EINTR);
1305 if (retmore == -1)
1306 goto proxyfail;
1307 ret += retmore;
1308 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1309 } while (ret < size);
1310
1311 } /* end scope for getting rest of data for v2 */
1312
1313 /* At this point: if PROXYv2, we've read the exact size required for all data;
1314 if PROXYv1 then we've read "less than required for any valid line" and should
1315 read the rest". */
1316
1317 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1318 {
1319 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1320
1321 switch (cmd)
1322 {
1323 case 0x01: /* PROXY command */
1324 switch (hdr.v2.fam)
1325 {
1326 case 0x11: /* TCPv4 address type */
1327 iptype = US"IPv4";
1328 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1329 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1330 if (!string_is_ip_address(US tmpip, NULL))
1331 {
1332 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1333 goto proxyfail;
1334 }
1335 proxy_local_address = sender_host_address;
1336 sender_host_address = string_copy(US tmpip);
1337 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1338 proxy_local_port = sender_host_port;
1339 sender_host_port = tmpport;
1340 /* Save dest ip/port */
1341 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1342 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1343 if (!string_is_ip_address(US tmpip, NULL))
1344 {
1345 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1346 goto proxyfail;
1347 }
1348 proxy_external_address = string_copy(US tmpip);
1349 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1350 proxy_external_port = tmpport;
1351 goto done;
1352 case 0x21: /* TCPv6 address type */
1353 iptype = US"IPv6";
1354 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1355 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1356 if (!string_is_ip_address(US tmpip6, NULL))
1357 {
1358 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1359 goto proxyfail;
1360 }
1361 proxy_local_address = sender_host_address;
1362 sender_host_address = string_copy(US tmpip6);
1363 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1364 proxy_local_port = sender_host_port;
1365 sender_host_port = tmpport;
1366 /* Save dest ip/port */
1367 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1368 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1369 if (!string_is_ip_address(US tmpip6, NULL))
1370 {
1371 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1372 goto proxyfail;
1373 }
1374 proxy_external_address = string_copy(US tmpip6);
1375 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1376 proxy_external_port = tmpport;
1377 goto done;
1378 default:
1379 DEBUG(D_receive)
1380 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1381 hdr.v2.fam);
1382 goto proxyfail;
1383 }
1384 /* Unsupported protocol, keep local connection address */
1385 break;
1386 case 0x00: /* LOCAL command */
1387 /* Keep local connection address for LOCAL */
1388 iptype = US"local";
1389 break;
1390 default:
1391 DEBUG(D_receive)
1392 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1393 goto proxyfail;
1394 }
1395 }
1396 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1397 {
1398 uschar *p;
1399 uschar *end;
1400 uschar *sp; /* Utility variables follow */
1401 int tmp_port;
1402 int r2;
1403 char *endc;
1404
1405 /* get the rest of the line */
1406 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1407 if (r2 == -1)
1408 goto proxyfail;
1409 ret += r2;
1410
1411 p = string_copy(hdr.v1.line);
1412 end = memchr(p, '\r', ret - 1);
1413
1414 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1415 {
1416 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1417 goto proxyfail;
1418 }
1419 *end = '\0'; /* Terminate the string */
1420 size = end + 2 - p; /* Skip header + CRLF */
1421 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1422 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1423 /* Step through the string looking for the required fields. Ensure
1424 strict adherence to required formatting, exit for any error. */
1425 p += 5;
1426 if (!isspace(*(p++)))
1427 {
1428 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1429 goto proxyfail;
1430 }
1431 if (!Ustrncmp(p, CCS"TCP4", 4))
1432 iptype = US"IPv4";
1433 else if (!Ustrncmp(p,CCS"TCP6", 4))
1434 iptype = US"IPv6";
1435 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1436 {
1437 iptype = US"Unknown";
1438 goto done;
1439 }
1440 else
1441 {
1442 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1443 goto proxyfail;
1444 }
1445
1446 p += Ustrlen(iptype);
1447 if (!isspace(*(p++)))
1448 {
1449 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1450 goto proxyfail;
1451 }
1452 /* Find the end of the arg */
1453 if ((sp = Ustrchr(p, ' ')) == NULL)
1454 {
1455 DEBUG(D_receive)
1456 debug_printf("Did not find proxied src %s\n", iptype);
1457 goto proxyfail;
1458 }
1459 *sp = '\0';
1460 if(!string_is_ip_address(p, NULL))
1461 {
1462 DEBUG(D_receive)
1463 debug_printf("Proxied src arg is not an %s address\n", iptype);
1464 goto proxyfail;
1465 }
1466 proxy_local_address = sender_host_address;
1467 sender_host_address = p;
1468 p = sp + 1;
1469 if ((sp = Ustrchr(p, ' ')) == NULL)
1470 {
1471 DEBUG(D_receive)
1472 debug_printf("Did not find proxy dest %s\n", iptype);
1473 goto proxyfail;
1474 }
1475 *sp = '\0';
1476 if(!string_is_ip_address(p, NULL))
1477 {
1478 DEBUG(D_receive)
1479 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1480 goto proxyfail;
1481 }
1482 proxy_external_address = p;
1483 p = sp + 1;
1484 if ((sp = Ustrchr(p, ' ')) == NULL)
1485 {
1486 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1487 goto proxyfail;
1488 }
1489 *sp = '\0';
1490 tmp_port = strtol(CCS p, &endc, 10);
1491 if (*endc || tmp_port == 0)
1492 {
1493 DEBUG(D_receive)
1494 debug_printf("Proxied src port '%s' not an integer\n", p);
1495 goto proxyfail;
1496 }
1497 proxy_local_port = sender_host_port;
1498 sender_host_port = tmp_port;
1499 p = sp + 1;
1500 if ((sp = Ustrchr(p, '\0')) == NULL)
1501 {
1502 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1503 goto proxyfail;
1504 }
1505 tmp_port = strtol(CCS p, &endc, 10);
1506 if (*endc || tmp_port == 0)
1507 {
1508 DEBUG(D_receive)
1509 debug_printf("Proxy dest port '%s' not an integer\n", p);
1510 goto proxyfail;
1511 }
1512 proxy_external_port = tmp_port;
1513 /* Already checked for /r /n above. Good V1 header received. */
1514 }
1515 else
1516 {
1517 /* Wrong protocol */
1518 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1519 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1520 goto proxyfail;
1521 }
1522
1523 done:
1524 DEBUG(D_receive)
1525 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1526 yield = proxy_session;
1527
1528 /* Don't flush any potential buffer contents. Any input on proxyfail
1529 should cause a synchronization failure */
1530
1531 proxyfail:
1532 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1533
1534 bad:
1535 if (yield)
1536 {
1537 sender_host_name = NULL;
1538 (void) host_name_lookup();
1539 host_build_sender_fullhost();
1540 }
1541 else
1542 {
1543 f.proxy_session_failed = TRUE;
1544 DEBUG(D_receive)
1545 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1546 }
1547
1548 return;
1549 }
1550 #endif
1551
1552 /*************************************************
1553 * Read one command line *
1554 *************************************************/
1555
1556 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1557 There are sites that don't do this, and in any case internal SMTP probably
1558 should check only for LF. Consequently, we check here for LF only. The line
1559 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1560 an unknown command. The command is read into the global smtp_cmd_buffer so that
1561 it is available via $smtp_command.
1562
1563 The character reading routine sets up a timeout for each block actually read
1564 from the input (which may contain more than one command). We set up a special
1565 signal handler that closes down the session on a timeout. Control does not
1566 return when it runs.
1567
1568 Arguments:
1569 check_sync if TRUE, check synchronization rules if global option is TRUE
1570 buffer_lim maximum to buffer in lower layer
1571
1572 Returns: a code identifying the command (enumerated above)
1573 */
1574
1575 static int
1576 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1577 {
1578 int c;
1579 int ptr = 0;
1580 BOOL hadnull = FALSE;
1581
1582 had_command_timeout = 0;
1583 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1584
1585 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1586 {
1587 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1588 {
1589 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1590 return OTHER_CMD;
1591 }
1592 if (c == 0)
1593 {
1594 hadnull = TRUE;
1595 c = '?';
1596 }
1597 smtp_cmd_buffer[ptr++] = c;
1598 }
1599
1600 receive_linecount++; /* For BSMTP errors */
1601 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1602
1603 /* If hit end of file, return pseudo EOF command. Whether we have a
1604 part-line already read doesn't matter, since this is an error state. */
1605
1606 if (c == EOF) return EOF_CMD;
1607
1608 /* Remove any CR and white space at the end of the line, and terminate the
1609 string. */
1610
1611 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1612 smtp_cmd_buffer[ptr] = 0;
1613
1614 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1615
1616 /* NULLs are not allowed in SMTP commands */
1617
1618 if (hadnull) return BADCHAR_CMD;
1619
1620 /* Scan command list and return identity, having set the data pointer
1621 to the start of the actual data characters. Check for SMTP synchronization
1622 if required. */
1623
1624 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1625 {
1626 #ifdef SUPPORT_PROXY
1627 /* Only allow QUIT command if Proxy Protocol parsing failed */
1628 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1629 continue;
1630 #endif
1631 if ( p->len
1632 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1633 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1634 || smtp_cmd_buffer[p->len] == 0
1635 || smtp_cmd_buffer[p->len] == ' '
1636 ) )
1637 {
1638 if (smtp_inptr < smtp_inend && /* Outstanding input */
1639 p->cmd < sync_cmd_limit && /* Command should sync */
1640 check_sync && /* Local flag set */
1641 smtp_enforce_sync && /* Global flag set */
1642 sender_host_address != NULL && /* Not local input */
1643 !f.sender_host_notsocket) /* Really is a socket */
1644 return BADSYN_CMD;
1645
1646 /* The variables $smtp_command and $smtp_command_argument point into the
1647 unmodified input buffer. A copy of the latter is taken for actual
1648 processing, so that it can be chopped up into separate parts if necessary,
1649 for example, when processing a MAIL command options such as SIZE that can
1650 follow the sender address. */
1651
1652 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1653 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1654 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1655 smtp_cmd_data = smtp_data_buffer;
1656
1657 /* Count non-mail commands from those hosts that are controlled in this
1658 way. The default is all hosts. We don't waste effort checking the list
1659 until we get a non-mail command, but then cache the result to save checking
1660 again. If there's a DEFER while checking the host, assume it's in the list.
1661
1662 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1663 start of each incoming message by fiddling with the value in the table. */
1664
1665 if (!p->is_mail_cmd)
1666 {
1667 if (count_nonmail == TRUE_UNSET) count_nonmail =
1668 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1669 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1670 return TOO_MANY_NONMAIL_CMD;
1671 }
1672
1673 /* If there is data for a command that does not expect it, generate the
1674 error here. */
1675
1676 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1677 }
1678 }
1679
1680 #ifdef SUPPORT_PROXY
1681 /* Only allow QUIT command if Proxy Protocol parsing failed */
1682 if (proxy_session && f.proxy_session_failed)
1683 return PROXY_FAIL_IGNORE_CMD;
1684 #endif
1685
1686 /* Enforce synchronization for unknown commands */
1687
1688 if ( smtp_inptr < smtp_inend /* Outstanding input */
1689 && check_sync /* Local flag set */
1690 && smtp_enforce_sync /* Global flag set */
1691 && sender_host_address /* Not local input */
1692 && !f.sender_host_notsocket) /* Really is a socket */
1693 return BADSYN_CMD;
1694
1695 return OTHER_CMD;
1696 }
1697
1698
1699
1700 /*************************************************
1701 * Forced closedown of call *
1702 *************************************************/
1703
1704 /* This function is called from log.c when Exim is dying because of a serious
1705 disaster, and also from some other places. If an incoming non-batched SMTP
1706 channel is open, it swallows the rest of the incoming message if in the DATA
1707 phase, sends the reply string, and gives an error to all subsequent commands
1708 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1709 smtp_in.
1710
1711 Arguments:
1712 message SMTP reply string to send, excluding the code
1713
1714 Returns: nothing
1715 */
1716
1717 void
1718 smtp_closedown(uschar *message)
1719 {
1720 if (!smtp_in || smtp_batched_input) return;
1721 receive_swallow_smtp();
1722 smtp_printf("421 %s\r\n", FALSE, message);
1723
1724 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1725 {
1726 case EOF_CMD:
1727 return;
1728
1729 case QUIT_CMD:
1730 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1731 mac_smtp_fflush();
1732 return;
1733
1734 case RSET_CMD:
1735 smtp_printf("250 Reset OK\r\n", FALSE);
1736 break;
1737
1738 default:
1739 smtp_printf("421 %s\r\n", FALSE, message);
1740 break;
1741 }
1742 }
1743
1744
1745
1746
1747 /*************************************************
1748 * Set up connection info for logging *
1749 *************************************************/
1750
1751 /* This function is called when logging information about an SMTP connection.
1752 It sets up appropriate source information, depending on the type of connection.
1753 If sender_fullhost is NULL, we are at a very early stage of the connection;
1754 just use the IP address.
1755
1756 Argument: none
1757 Returns: a string describing the connection
1758 */
1759
1760 uschar *
1761 smtp_get_connection_info(void)
1762 {
1763 const uschar * hostname = sender_fullhost
1764 ? sender_fullhost : sender_host_address;
1765
1766 if (host_checking)
1767 return string_sprintf("SMTP connection from %s", hostname);
1768
1769 if (f.sender_host_unknown || f.sender_host_notsocket)
1770 return string_sprintf("SMTP connection from %s", sender_ident);
1771
1772 if (f.is_inetd)
1773 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1774
1775 if (LOGGING(incoming_interface) && interface_address)
1776 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1777 interface_address, interface_port);
1778
1779 return string_sprintf("SMTP connection from %s", hostname);
1780 }
1781
1782
1783
1784 #ifndef DISABLE_TLS
1785 /* Append TLS-related information to a log line
1786
1787 Arguments:
1788 g String under construction: allocated string to extend, or NULL
1789
1790 Returns: Allocated string or NULL
1791 */
1792 static gstring *
1793 s_tlslog(gstring * g)
1794 {
1795 if (LOGGING(tls_cipher) && tls_in.cipher)
1796 {
1797 g = string_append(g, 2, US" X=", tls_in.cipher);
1798 #ifdef EXPERIMENTAL_TLS_RESUME
1799 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1800 g = string_catn(g, US"*", 1);
1801 #endif
1802 }
1803 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1804 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1805 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1806 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1807 if (LOGGING(tls_sni) && tls_in.sni)
1808 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1809 return g;
1810 }
1811 #endif
1812
1813 /*************************************************
1814 * Log lack of MAIL if so configured *
1815 *************************************************/
1816
1817 /* This function is called when an SMTP session ends. If the log selector
1818 smtp_no_mail is set, write a log line giving some details of what has happened
1819 in the SMTP session.
1820
1821 Arguments: none
1822 Returns: nothing
1823 */
1824
1825 void
1826 smtp_log_no_mail(void)
1827 {
1828 uschar * sep, * s;
1829 gstring * g = NULL;
1830
1831 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1832 return;
1833
1834 if (sender_host_authenticated)
1835 {
1836 g = string_append(g, 2, US" A=", sender_host_authenticated);
1837 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1838 }
1839
1840 #ifndef DISABLE_TLS
1841 g = s_tlslog(g);
1842 #endif
1843
1844 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1845
1846 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1847 if (smtp_connection_had[i] != SCH_NONE)
1848 {
1849 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1850 sep = US",";
1851 }
1852
1853 for (int i = 0; i < smtp_ch_index; i++)
1854 {
1855 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1856 sep = US",";
1857 }
1858
1859 if (!(s = string_from_gstring(g))) s = US"";
1860
1861 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1862 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1863 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1864 }
1865
1866
1867 /* Return list of recent smtp commands */
1868
1869 uschar *
1870 smtp_cmd_hist(void)
1871 {
1872 gstring * list = NULL;
1873 uschar * s;
1874
1875 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1876 if (smtp_connection_had[i] != SCH_NONE)
1877 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1878
1879 for (int i = 0; i < smtp_ch_index; i++)
1880 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1881
1882 s = string_from_gstring(list);
1883 return s ? s : US"";
1884 }
1885
1886
1887
1888
1889 /*************************************************
1890 * Check HELO line and set sender_helo_name *
1891 *************************************************/
1892
1893 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1894 the domain name of the sending host, or an ip literal in square brackets. The
1895 argument is placed in sender_helo_name, which is in malloc store, because it
1896 must persist over multiple incoming messages. If helo_accept_junk is set, this
1897 host is permitted to send any old junk (needed for some broken hosts).
1898 Otherwise, helo_allow_chars can be used for rogue characters in general
1899 (typically people want to let in underscores).
1900
1901 Argument:
1902 s the data portion of the line (already past any white space)
1903
1904 Returns: TRUE or FALSE
1905 */
1906
1907 static BOOL
1908 check_helo(uschar *s)
1909 {
1910 uschar *start = s;
1911 uschar *end = s + Ustrlen(s);
1912 BOOL yield = fl.helo_accept_junk;
1913
1914 /* Discard any previous helo name */
1915
1916 sender_helo_name = NULL;
1917
1918 /* Skip tests if junk is permitted. */
1919
1920 if (!yield)
1921
1922 /* Allow the new standard form for IPv6 address literals, namely,
1923 [IPv6:....], and because someone is bound to use it, allow an equivalent
1924 IPv4 form. Allow plain addresses as well. */
1925
1926 if (*s == '[')
1927 {
1928 if (end[-1] == ']')
1929 {
1930 end[-1] = 0;
1931 if (strncmpic(s, US"[IPv6:", 6) == 0)
1932 yield = (string_is_ip_address(s+6, NULL) == 6);
1933 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1934 yield = (string_is_ip_address(s+6, NULL) == 4);
1935 else
1936 yield = (string_is_ip_address(s+1, NULL) != 0);
1937 end[-1] = ']';
1938 }
1939 }
1940
1941 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1942 that have been configured (usually underscore - sigh). */
1943
1944 else if (*s)
1945 for (yield = TRUE; *s; s++)
1946 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1947 Ustrchr(helo_allow_chars, *s) == NULL)
1948 {
1949 yield = FALSE;
1950 break;
1951 }
1952
1953 /* Save argument if OK */
1954
1955 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
1956 return yield;
1957 }
1958
1959
1960
1961
1962
1963 /*************************************************
1964 * Extract SMTP command option *
1965 *************************************************/
1966
1967 /* This function picks the next option setting off the end of smtp_cmd_data. It
1968 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1969 things that can appear there.
1970
1971 Arguments:
1972 name point this at the name
1973 value point this at the data string
1974
1975 Returns: TRUE if found an option
1976 */
1977
1978 static BOOL
1979 extract_option(uschar **name, uschar **value)
1980 {
1981 uschar *n;
1982 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1983 while (isspace(*v)) v--;
1984 v[1] = 0;
1985 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1986 {
1987 /* Take care to not stop at a space embedded in a quoted local-part */
1988
1989 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1990 v--;
1991 }
1992
1993 n = v;
1994 if (*v == '=')
1995 {
1996 while(isalpha(n[-1])) n--;
1997 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1998 if (!isspace(n[-1])) return FALSE;
1999 n[-1] = 0;
2000 }
2001 else
2002 {
2003 n++;
2004 if (v == smtp_cmd_data) return FALSE;
2005 }
2006 *v++ = 0;
2007 *name = n;
2008 *value = v;
2009 return TRUE;
2010 }
2011
2012
2013
2014
2015
2016 /*************************************************
2017 * Reset for new message *
2018 *************************************************/
2019
2020 /* This function is called whenever the SMTP session is reset from
2021 within either of the setup functions; also from the daemon loop.
2022
2023 Argument: the stacking pool storage reset point
2024 Returns: nothing
2025 */
2026
2027 void *
2028 smtp_reset(void *reset_point)
2029 {
2030 recipients_list = NULL;
2031 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2032 raw_recipients_count = recipients_count = recipients_list_max = 0;
2033 message_linecount = 0;
2034 message_size = -1;
2035 acl_added_headers = NULL;
2036 acl_removed_headers = NULL;
2037 f.queue_only_policy = FALSE;
2038 rcpt_smtp_response = NULL;
2039 fl.rcpt_smtp_response_same = TRUE;
2040 fl.rcpt_in_progress = FALSE;
2041 f.deliver_freeze = FALSE; /* Can be set by ACL */
2042 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2043 fake_response = OK; /* Can be set by ACL */
2044 #ifdef WITH_CONTENT_SCAN
2045 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2046 #endif
2047 f.submission_mode = FALSE; /* Can be set by ACL */
2048 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2049 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2050 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2051 sending_ip_address = NULL;
2052 return_path = sender_address = NULL;
2053 sender_data = NULL; /* Can be set by ACL */
2054 deliver_localpart_parent = deliver_localpart_orig = NULL;
2055 deliver_domain_parent = deliver_domain_orig = NULL;
2056 callout_address = NULL;
2057 submission_name = NULL; /* Can be set by ACL */
2058 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2059 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2060 sender_verified_list = NULL; /* No senders verified */
2061 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2062 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2063
2064 authenticated_sender = NULL;
2065 #ifdef EXPERIMENTAL_BRIGHTMAIL
2066 bmi_run = 0;
2067 bmi_verdicts = NULL;
2068 #endif
2069 dnslist_domain = dnslist_matched = NULL;
2070 #ifdef SUPPORT_SPF
2071 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2072 spf_result_guessed = FALSE;
2073 #endif
2074 #ifndef DISABLE_DKIM
2075 dkim_cur_signer = dkim_signers =
2076 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2077 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2078 f.dkim_disable_verify = FALSE;
2079 dkim_collect_input = 0;
2080 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2081 dkim_key_length = 0;
2082 #endif
2083 #ifdef SUPPORT_DMARC
2084 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2085 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2086 dmarc_used_domain = NULL;
2087 #endif
2088 #ifdef EXPERIMENTAL_ARC
2089 arc_state = arc_state_reason = NULL;
2090 #endif
2091 dsn_ret = 0;
2092 dsn_envid = NULL;
2093 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2094 #ifndef DISABLE_PRDR
2095 prdr_requested = FALSE;
2096 #endif
2097 #ifdef SUPPORT_I18N
2098 message_smtputf8 = FALSE;
2099 #endif
2100 body_linecount = body_zerocount = 0;
2101
2102 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2103 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2104 /* Note that ratelimiters_conn persists across resets. */
2105
2106 /* Reset message ACL variables */
2107
2108 acl_var_m = NULL;
2109
2110 /* The message body variables use malloc store. They may be set if this is
2111 not the first message in an SMTP session and the previous message caused them
2112 to be referenced in an ACL. */
2113
2114 if (message_body)
2115 {
2116 store_free(message_body);
2117 message_body = NULL;
2118 }
2119
2120 if (message_body_end)
2121 {
2122 store_free(message_body_end);
2123 message_body_end = NULL;
2124 }
2125
2126 /* Warning log messages are also saved in malloc store. They are saved to avoid
2127 repetition in the same message, but it seems right to repeat them for different
2128 messages. */
2129
2130 while (acl_warn_logged)
2131 {
2132 string_item *this = acl_warn_logged;
2133 acl_warn_logged = acl_warn_logged->next;
2134 store_free(this);
2135 }
2136 store_reset(reset_point);
2137 return store_mark();
2138 }
2139
2140
2141
2142
2143
2144 /*************************************************
2145 * Initialize for incoming batched SMTP message *
2146 *************************************************/
2147
2148 /* This function is called from smtp_setup_msg() in the case when
2149 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2150 of messages in one file with SMTP commands between them. All errors must be
2151 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2152 relevant. After an error on a sender, or an invalid recipient, the remainder
2153 of the message is skipped. The value of received_protocol is already set.
2154
2155 Argument: none
2156 Returns: > 0 message successfully started (reached DATA)
2157 = 0 QUIT read or end of file reached
2158 < 0 should not occur
2159 */
2160
2161 static int
2162 smtp_setup_batch_msg(void)
2163 {
2164 int done = 0;
2165 rmark reset_point = store_mark();
2166
2167 /* Save the line count at the start of each transaction - single commands
2168 like HELO and RSET count as whole transactions. */
2169
2170 bsmtp_transaction_linecount = receive_linecount;
2171
2172 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2173
2174 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2175 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2176
2177 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2178 value. The values are 2 larger than the required yield of the function. */
2179
2180 while (done <= 0)
2181 {
2182 uschar *errmess;
2183 uschar *recipient = NULL;
2184 int start, end, sender_domain, recipient_domain;
2185
2186 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2187 {
2188 /* The HELO/EHLO commands set sender_address_helo if they have
2189 valid data; otherwise they are ignored, except that they do
2190 a reset of the state. */
2191
2192 case HELO_CMD:
2193 case EHLO_CMD:
2194
2195 check_helo(smtp_cmd_data);
2196 /* Fall through */
2197
2198 case RSET_CMD:
2199 cancel_cutthrough_connection(TRUE, US"RSET received");
2200 reset_point = smtp_reset(reset_point);
2201 bsmtp_transaction_linecount = receive_linecount;
2202 break;
2203
2204
2205 /* The MAIL FROM command requires an address as an operand. All we
2206 do here is to parse it for syntactic correctness. The form "<>" is
2207 a special case which converts into an empty string. The start/end
2208 pointers in the original are not used further for this address, as
2209 it is the canonical extracted address which is all that is kept. */
2210
2211 case MAIL_CMD:
2212 smtp_mailcmd_count++; /* Count for no-mail log */
2213 if (sender_address != NULL)
2214 /* The function moan_smtp_batch() does not return. */
2215 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2216
2217 if (smtp_cmd_data[0] == 0)
2218 /* The function moan_smtp_batch() does not return. */
2219 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2220
2221 /* Reset to start of message */
2222
2223 cancel_cutthrough_connection(TRUE, US"MAIL received");
2224 reset_point = smtp_reset(reset_point);
2225
2226 /* Apply SMTP rewrite */
2227
2228 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2229 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2230 US"", global_rewrite_rules) : smtp_cmd_data;
2231
2232 /* Extract the address; the TRUE flag allows <> as valid */
2233
2234 raw_sender =
2235 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2236 TRUE);
2237
2238 if (!raw_sender)
2239 /* The function moan_smtp_batch() does not return. */
2240 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2241
2242 sender_address = string_copy(raw_sender);
2243
2244 /* Qualify unqualified sender addresses if permitted to do so. */
2245
2246 if ( !sender_domain
2247 && sender_address[0] != 0 && sender_address[0] != '@')
2248 if (f.allow_unqualified_sender)
2249 {
2250 sender_address = rewrite_address_qualify(sender_address, FALSE);
2251 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2252 "and rewritten\n", raw_sender);
2253 }
2254 /* The function moan_smtp_batch() does not return. */
2255 else
2256 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2257 "a domain");
2258 break;
2259
2260
2261 /* The RCPT TO command requires an address as an operand. All we do
2262 here is to parse it for syntactic correctness. There may be any number
2263 of RCPT TO commands, specifying multiple senders. We build them all into
2264 a data structure that is in argc/argv format. The start/end values
2265 given by parse_extract_address are not used, as we keep only the
2266 extracted address. */
2267
2268 case RCPT_CMD:
2269 if (!sender_address)
2270 /* The function moan_smtp_batch() does not return. */
2271 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2272
2273 if (smtp_cmd_data[0] == 0)
2274 /* The function moan_smtp_batch() does not return. */
2275 moan_smtp_batch(smtp_cmd_buffer,
2276 "501 RCPT TO must have an address operand");
2277
2278 /* Check maximum number allowed */
2279
2280 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2281 /* The function moan_smtp_batch() does not return. */
2282 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2283 recipients_max_reject? "552": "452");
2284
2285 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2286 recipient address */
2287
2288 recipient = rewrite_existflags & rewrite_smtp
2289 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2290 global_rewrite_rules)
2291 : smtp_cmd_data;
2292
2293 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2294 &recipient_domain, FALSE);
2295
2296 if (!recipient)
2297 /* The function moan_smtp_batch() does not return. */
2298 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2299
2300 /* If the recipient address is unqualified, qualify it if permitted. Then
2301 add it to the list of recipients. */
2302
2303 if (!recipient_domain)
2304 if (f.allow_unqualified_recipient)
2305 {
2306 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2307 recipient);
2308 recipient = rewrite_address_qualify(recipient, TRUE);
2309 }
2310 /* The function moan_smtp_batch() does not return. */
2311 else
2312 moan_smtp_batch(smtp_cmd_buffer,
2313 "501 recipient address must contain a domain");
2314
2315 receive_add_recipient(recipient, -1);
2316 break;
2317
2318
2319 /* The DATA command is legal only if it follows successful MAIL FROM
2320 and RCPT TO commands. This function is complete when a valid DATA
2321 command is encountered. */
2322
2323 case DATA_CMD:
2324 if (!sender_address || recipients_count <= 0)
2325 /* The function moan_smtp_batch() does not return. */
2326 if (!sender_address)
2327 moan_smtp_batch(smtp_cmd_buffer,
2328 "503 MAIL FROM:<sender> command must precede DATA");
2329 else
2330 moan_smtp_batch(smtp_cmd_buffer,
2331 "503 RCPT TO:<recipient> must precede DATA");
2332 else
2333 {
2334 done = 3; /* DATA successfully achieved */
2335 message_ended = END_NOTENDED; /* Indicate in middle of message */
2336 }
2337 break;
2338
2339
2340 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2341
2342 case VRFY_CMD:
2343 case EXPN_CMD:
2344 case HELP_CMD:
2345 case NOOP_CMD:
2346 case ETRN_CMD:
2347 bsmtp_transaction_linecount = receive_linecount;
2348 break;
2349
2350
2351 case EOF_CMD:
2352 case QUIT_CMD:
2353 done = 2;
2354 break;
2355
2356
2357 case BADARG_CMD:
2358 /* The function moan_smtp_batch() does not return. */
2359 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2360 break;
2361
2362
2363 case BADCHAR_CMD:
2364 /* The function moan_smtp_batch() does not return. */
2365 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2366 break;
2367
2368
2369 default:
2370 /* The function moan_smtp_batch() does not return. */
2371 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2372 break;
2373 }
2374 }
2375
2376 return done - 2; /* Convert yield values */
2377 }
2378
2379
2380
2381
2382 #ifndef DISABLE_TLS
2383 static BOOL
2384 smtp_log_tls_fail(uschar * errstr)
2385 {
2386 uschar * conn_info = smtp_get_connection_info();
2387
2388 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2389 /* I'd like to get separated H= here, but too hard for now */
2390
2391 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2392 return FALSE;
2393 }
2394 #endif
2395
2396
2397
2398
2399 #ifdef TCP_FASTOPEN
2400 static void
2401 tfo_in_check(void)
2402 {
2403 # ifdef TCP_INFO
2404 struct tcp_info tinfo;
2405 socklen_t len = sizeof(tinfo);
2406
2407 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2408 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2409 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2410 {
2411 DEBUG(D_receive)
2412 debug_printf("TCP_FASTOPEN mode connection (ACKd data-on-SYN)\n");
2413 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2414 }
2415 else
2416 # endif
2417 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2418 {
2419 DEBUG(D_receive)
2420 debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2421 f.tcp_in_fastopen = TRUE;
2422 }
2423 # ifdef __FreeBSD__
2424 else if (tinfo.tcpi_options & TCPOPT_FAST_OPEN)
2425 {
2426 /* This only tells us that some combination of the TCP options was used. It
2427 can be a TFO-R received (as of 12.1). However, pretend it shows real usage
2428 (that an acceptable TFO-C was received and acted on). Ignore the possibility
2429 of data-on-SYN for now. */
2430 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (TFO option used)\n");
2431 f.tcp_in_fastopen = TRUE;
2432 }
2433 # endif
2434 # endif
2435 else DEBUG(D_receive)
2436 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2437 }
2438 #endif
2439
2440
2441 /*************************************************
2442 * Start an SMTP session *
2443 *************************************************/
2444
2445 /* This function is called at the start of an SMTP session. Thereafter,
2446 smtp_setup_msg() is called to initiate each separate message. This
2447 function does host-specific testing, and outputs the banner line.
2448
2449 Arguments: none
2450 Returns: FALSE if the session can not continue; something has
2451 gone wrong, or the connection to the host is blocked
2452 */
2453
2454 BOOL
2455 smtp_start_session(void)
2456 {
2457 int esclen;
2458 uschar *user_msg, *log_msg;
2459 uschar *code, *esc;
2460 uschar *p, *s;
2461 gstring * ss;
2462
2463 gettimeofday(&smtp_connection_start, NULL);
2464 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2465 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2466 smtp_ch_index = 0;
2467
2468 /* Default values for certain variables */
2469
2470 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2471 smtp_mailcmd_count = 0;
2472 count_nonmail = TRUE_UNSET;
2473 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2474 smtp_delay_mail = smtp_rlm_base;
2475 fl.auth_advertised = FALSE;
2476 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2477 f.pipelining_enable = TRUE;
2478 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2479 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2480
2481 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2482 authentication settings from -oMaa to remain in force. */
2483
2484 if (!host_checking && !f.sender_host_notsocket)
2485 sender_host_auth_pubname = sender_host_authenticated = NULL;
2486 authenticated_by = NULL;
2487
2488 #ifndef DISABLE_TLS
2489 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2490 tls_in.ourcert = tls_in.peercert = NULL;
2491 tls_in.sni = NULL;
2492 tls_in.ocsp = OCSP_NOT_REQ;
2493 fl.tls_advertised = FALSE;
2494 #endif
2495 fl.dsn_advertised = FALSE;
2496 #ifdef SUPPORT_I18N
2497 fl.smtputf8_advertised = FALSE;
2498 #endif
2499
2500 /* Reset ACL connection variables */
2501
2502 acl_var_c = NULL;
2503
2504 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2505
2506 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, TRUE);
2507
2508 smtp_cmd_buffer[0] = 0;
2509 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2510
2511 /* For batched input, the protocol setting can be overridden from the
2512 command line by a trusted caller. */
2513
2514 if (smtp_batched_input)
2515 {
2516 if (!received_protocol) received_protocol = US"local-bsmtp";
2517 }
2518
2519 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2520 reset later if any of EHLO/AUTH/STARTTLS are received. */
2521
2522 else
2523 received_protocol =
2524 (sender_host_address ? protocols : protocols_local) [pnormal];
2525
2526 /* Set up the buffer for inputting using direct read() calls, and arrange to
2527 call the local functions instead of the standard C ones. Place a NUL at the
2528 end of the buffer to safety-stop C-string reads from it. */
2529
2530 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2531 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2532 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2533
2534 receive_getc = smtp_getc;
2535 receive_getbuf = smtp_getbuf;
2536 receive_get_cache = smtp_get_cache;
2537 receive_ungetc = smtp_ungetc;
2538 receive_feof = smtp_feof;
2539 receive_ferror = smtp_ferror;
2540 receive_smtp_buffered = smtp_buffered;
2541 smtp_inptr = smtp_inend = smtp_inbuffer;
2542 smtp_had_eof = smtp_had_error = 0;
2543
2544 /* Set up the message size limit; this may be host-specific */
2545
2546 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2547 if (expand_string_message)
2548 {
2549 if (thismessage_size_limit == -1)
2550 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2551 "%s", expand_string_message);
2552 else
2553 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2554 "%s", expand_string_message);
2555 smtp_closedown(US"Temporary local problem - please try later");
2556 return FALSE;
2557 }
2558
2559 /* When a message is input locally via the -bs or -bS options, sender_host_
2560 unknown is set unless -oMa was used to force an IP address, in which case it
2561 is checked like a real remote connection. When -bs is used from inetd, this
2562 flag is not set, causing the sending host to be checked. The code that deals
2563 with IP source routing (if configured) is never required for -bs or -bS and
2564 the flag sender_host_notsocket is used to suppress it.
2565
2566 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2567 reserve for certain hosts and/or networks. */
2568
2569 if (!f.sender_host_unknown)
2570 {
2571 int rc;
2572 BOOL reserved_host = FALSE;
2573
2574 /* Look up IP options (source routing info) on the socket if this is not an
2575 -oMa "host", and if any are found, log them and drop the connection.
2576
2577 Linux (and others now, see below) is different to everyone else, so there
2578 has to be some conditional compilation here. Versions of Linux before 2.1.15
2579 used a structure whose name was "options". Somebody finally realized that
2580 this name was silly, and it got changed to "ip_options". I use the
2581 newer name here, but there is a fudge in the script that sets up os.h
2582 to define a macro in older Linux systems.
2583
2584 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2585 glibc 2, which has chosen ip_opts for the structure name. This is now
2586 really a glibc thing rather than a Linux thing, so the condition name
2587 has been changed to reflect this. It is relevant also to GNU/Hurd.
2588
2589 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2590 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2591 a special macro defined in the os.h file.
2592
2593 Some DGUX versions on older hardware appear not to support IP options at
2594 all, so there is now a general macro which can be set to cut out this
2595 support altogether.
2596
2597 How to do this properly in IPv6 is not yet known. */
2598
2599 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2600
2601 #ifdef GLIBC_IP_OPTIONS
2602 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2603 #define OPTSTYLE 1
2604 #else
2605 #define OPTSTYLE 2
2606 #endif
2607 #elif defined DARWIN_IP_OPTIONS
2608 #define OPTSTYLE 2
2609 #else
2610 #define OPTSTYLE 3
2611 #endif
2612
2613 if (!host_checking && !f.sender_host_notsocket)
2614 {
2615 #if OPTSTYLE == 1
2616 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2617 struct ip_options *ipopt = store_get(optlen, FALSE);
2618 #elif OPTSTYLE == 2
2619 struct ip_opts ipoptblock;
2620 struct ip_opts *ipopt = &ipoptblock;
2621 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2622 #else
2623 struct ipoption ipoptblock;
2624 struct ipoption *ipopt = &ipoptblock;
2625 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2626 #endif
2627
2628 /* Occasional genuine failures of getsockopt() have been seen - for
2629 example, "reset by peer". Therefore, just log and give up on this
2630 call, unless the error is ENOPROTOOPT. This error is given by systems
2631 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2632 of writing. So for that error, carry on - we just can't do an IP options
2633 check. */
2634
2635 DEBUG(D_receive) debug_printf("checking for IP options\n");
2636
2637 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2638 &optlen) < 0)
2639 {
2640 if (errno != ENOPROTOOPT)
2641 {
2642 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2643 host_and_ident(FALSE), strerror(errno));
2644 smtp_printf("451 SMTP service not available\r\n", FALSE);
2645 return FALSE;
2646 }
2647 }
2648
2649 /* Deal with any IP options that are set. On the systems I have looked at,
2650 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2651 more logging data than will fit in big_buffer. Nevertheless, after somebody
2652 questioned this code, I've added in some paranoid checking. */
2653
2654 else if (optlen > 0)
2655 {
2656 uschar *p = big_buffer;
2657 uschar *pend = big_buffer + big_buffer_size;
2658 uschar *adptr;
2659 int optcount;
2660 struct in_addr addr;
2661
2662 #if OPTSTYLE == 1
2663 uschar *optstart = US (ipopt->__data);
2664 #elif OPTSTYLE == 2
2665 uschar *optstart = US (ipopt->ip_opts);
2666 #else
2667 uschar *optstart = US (ipopt->ipopt_list);
2668 #endif
2669
2670 DEBUG(D_receive) debug_printf("IP options exist\n");
2671
2672 Ustrcpy(p, "IP options on incoming call:");
2673 p += Ustrlen(p);
2674
2675 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2676 switch (*opt)
2677 {
2678 case IPOPT_EOL:
2679 opt = NULL;
2680 break;
2681
2682 case IPOPT_NOP:
2683 opt++;
2684 break;
2685
2686 case IPOPT_SSRR:
2687 case IPOPT_LSRR:
2688 if (!string_format(p, pend-p, " %s [@%s",
2689 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2690 #if OPTSTYLE == 1
2691 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2692 #elif OPTSTYLE == 2
2693 inet_ntoa(ipopt->ip_dst)))
2694 #else
2695 inet_ntoa(ipopt->ipopt_dst)))
2696 #endif
2697 {
2698 opt = NULL;
2699 break;
2700 }
2701
2702 p += Ustrlen(p);
2703 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2704 adptr = opt + 3;
2705 while (optcount-- > 0)
2706 {
2707 memcpy(&addr, adptr, sizeof(addr));
2708 if (!string_format(p, pend - p - 1, "%s%s",
2709 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2710 {
2711 opt = NULL;
2712 break;
2713 }
2714 p += Ustrlen(p);
2715 adptr += sizeof(struct in_addr);
2716 }
2717 *p++ = ']';
2718 opt += opt[1];
2719 break;
2720
2721 default:
2722 {
2723 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2724 Ustrcat(p, "[ ");
2725 p += 2;
2726 for (int i = 0; i < opt[1]; i++)
2727 p += sprintf(CS p, "%2.2x ", opt[i]);
2728 *p++ = ']';
2729 }
2730 opt += opt[1];
2731 break;
2732 }
2733
2734 *p = 0;
2735 log_write(0, LOG_MAIN, "%s", big_buffer);
2736
2737 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2738
2739 log_write(0, LOG_MAIN|LOG_REJECT,
2740 "connection from %s refused (IP options)", host_and_ident(FALSE));
2741
2742 smtp_printf("554 SMTP service not available\r\n", FALSE);
2743 return FALSE;
2744 }
2745
2746 /* Length of options = 0 => there are no options */
2747
2748 else DEBUG(D_receive) debug_printf("no IP options found\n");
2749 }
2750 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2751
2752 /* Set keep-alive in socket options. The option is on by default. This
2753 setting is an attempt to get rid of some hanging connections that stick in
2754 read() when the remote end (usually a dialup) goes away. */
2755
2756 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2757 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2758
2759 /* If the current host matches host_lookup, set the name by doing a
2760 reverse lookup. On failure, sender_host_name will be NULL and
2761 host_lookup_failed will be TRUE. This may or may not be serious - optional
2762 checks later. */
2763
2764 if (verify_check_host(&host_lookup) == OK)
2765 {
2766 (void)host_name_lookup();
2767 host_build_sender_fullhost();
2768 }
2769
2770 /* Delay this until we have the full name, if it is looked up. */
2771
2772 set_process_info("handling incoming connection from %s",
2773 host_and_ident(FALSE));
2774
2775 /* Expand smtp_receive_timeout, if needed */
2776
2777 if (smtp_receive_timeout_s)
2778 {
2779 uschar * exp;
2780 if ( !(exp = expand_string(smtp_receive_timeout_s))
2781 || !(*exp)
2782 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2783 )
2784 log_write(0, LOG_MAIN|LOG_PANIC,
2785 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2786 }
2787
2788 /* Test for explicit connection rejection */
2789
2790 if (verify_check_host(&host_reject_connection) == OK)
2791 {
2792 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2793 "from %s (host_reject_connection)", host_and_ident(FALSE));
2794 smtp_printf("554 SMTP service not available\r\n", FALSE);
2795 return FALSE;
2796 }
2797
2798 /* Test with TCP Wrappers if so configured. There is a problem in that
2799 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2800 such as disks dying. In these cases, it is desirable to reject with a 4xx
2801 error instead of a 5xx error. There isn't a "right" way to detect such
2802 problems. The following kludge is used: errno is zeroed before calling
2803 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2804 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2805 not exist). */
2806
2807 #ifdef USE_TCP_WRAPPERS
2808 errno = 0;
2809 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2810 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2811 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2812 expand_string_message);
2813
2814 if (!hosts_ctl(tcp_wrappers_name,
2815 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2816 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2817 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2818 {
2819 if (errno == 0 || errno == ENOENT)
2820 {
2821 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2822 log_write(L_connection_reject,
2823 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2824 "(tcp wrappers)", host_and_ident(FALSE));
2825 smtp_printf("554 SMTP service not available\r\n", FALSE);
2826 }
2827 else
2828 {
2829 int save_errno = errno;
2830 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2831 "errno value %d\n", save_errno);
2832 log_write(L_connection_reject,
2833 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2834 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2835 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2836 }
2837 return FALSE;
2838 }
2839 #endif
2840
2841 /* Check for reserved slots. The value of smtp_accept_count has already been
2842 incremented to include this process. */
2843
2844 if (smtp_accept_max > 0 &&
2845 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2846 {
2847 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2848 {
2849 log_write(L_connection_reject,
2850 LOG_MAIN, "temporarily refused connection from %s: not in "
2851 "reserve list: connected=%d max=%d reserve=%d%s",
2852 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2853 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2854 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2855 "please try again later\r\n", FALSE, smtp_active_hostname);
2856 return FALSE;
2857 }
2858 reserved_host = TRUE;
2859 }
2860
2861 /* If a load level above which only messages from reserved hosts are
2862 accepted is set, check the load. For incoming calls via the daemon, the
2863 check is done in the superior process if there are no reserved hosts, to
2864 save a fork. In all cases, the load average will already be available
2865 in a global variable at this point. */
2866
2867 if (smtp_load_reserve >= 0 &&
2868 load_average > smtp_load_reserve &&
2869 !reserved_host &&
2870 verify_check_host(&smtp_reserve_hosts) != OK)
2871 {
2872 log_write(L_connection_reject,
2873 LOG_MAIN, "temporarily refused connection from %s: not in "
2874 "reserve list and load average = %.2f", host_and_ident(FALSE),
2875 (double)load_average/1000.0);
2876 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2877 smtp_active_hostname);
2878 return FALSE;
2879 }
2880
2881 /* Determine whether unqualified senders or recipients are permitted
2882 for this host. Unfortunately, we have to do this every time, in order to
2883 set the flags so that they can be inspected when considering qualifying
2884 addresses in the headers. For a site that permits no qualification, this
2885 won't take long, however. */
2886
2887 f.allow_unqualified_sender =
2888 verify_check_host(&sender_unqualified_hosts) == OK;
2889
2890 f.allow_unqualified_recipient =
2891 verify_check_host(&recipient_unqualified_hosts) == OK;
2892
2893 /* Determine whether HELO/EHLO is required for this host. The requirement
2894 can be hard or soft. */
2895
2896 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2897 if (!fl.helo_required)
2898 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2899
2900 /* Determine whether this hosts is permitted to send syntactic junk
2901 after a HELO or EHLO command. */
2902
2903 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2904 }
2905
2906 /* For batch SMTP input we are now done. */
2907
2908 if (smtp_batched_input) return TRUE;
2909
2910 /* If valid Proxy Protocol source is connecting, set up session.
2911 * Failure will not allow any SMTP function other than QUIT. */
2912
2913 #ifdef SUPPORT_PROXY
2914 proxy_session = FALSE;
2915 f.proxy_session_failed = FALSE;
2916 if (check_proxy_protocol_host())
2917 setup_proxy_protocol_host();
2918 #endif
2919
2920 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2921 smtps port for use with older style SSL MTAs. */
2922
2923 #ifndef DISABLE_TLS
2924 if (tls_in.on_connect)
2925 {
2926 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2927 return smtp_log_tls_fail(user_msg);
2928 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2929 }
2930 #endif
2931
2932 /* Run the connect ACL if it exists */
2933
2934 user_msg = NULL;
2935 if (acl_smtp_connect)
2936 {
2937 int rc;
2938 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2939 &log_msg)) != OK)
2940 {
2941 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2942 return FALSE;
2943 }
2944 }
2945
2946 /* Output the initial message for a two-way SMTP connection. It may contain
2947 newlines, which then cause a multi-line response to be given. */
2948
2949 code = US"220"; /* Default status code */
2950 esc = US""; /* Default extended status code */
2951 esclen = 0; /* Length of esc */
2952
2953 if (!user_msg)
2954 {
2955 if (!(s = expand_string(smtp_banner)))
2956 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2957 "failed: %s", smtp_banner, expand_string_message);
2958 }
2959 else
2960 {
2961 int codelen = 3;
2962 s = user_msg;
2963 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2964 if (codelen > 4)
2965 {
2966 esc = code + 4;
2967 esclen = codelen - 4;
2968 }
2969 }
2970
2971 /* Remove any terminating newlines; might as well remove trailing space too */
2972
2973 p = s + Ustrlen(s);
2974 while (p > s && isspace(p[-1])) p--;
2975 *p = 0;
2976
2977 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2978 is all contained in a single IP packet. The original code wrote out the
2979 greeting using several calls to fprint/fputc, and on busy servers this could
2980 cause it to be split over more than one packet - which caused CC:Mail to fall
2981 over when it got the second part of the greeting after sending its first
2982 command. Sigh. To try to avoid this, build the complete greeting message
2983 first, and output it in one fell swoop. This gives a better chance of it
2984 ending up as a single packet. */
2985
2986 ss = string_get(256);
2987
2988 p = s;
2989 do /* At least once, in case we have an empty string */
2990 {
2991 int len;
2992 uschar *linebreak = Ustrchr(p, '\n');
2993 ss = string_catn(ss, code, 3);
2994 if (!linebreak)
2995 {
2996 len = Ustrlen(p);
2997 ss = string_catn(ss, US" ", 1);
2998 }
2999 else
3000 {
3001 len = linebreak - p;
3002 ss = string_catn(ss, US"-", 1);
3003 }
3004 ss = string_catn(ss, esc, esclen);
3005 ss = string_catn(ss, p, len);
3006 ss = string_catn(ss, US"\r\n", 2);
3007 p += len;
3008 if (linebreak) p++;
3009 }
3010 while (*p);
3011
3012 /* Before we write the banner, check that there is no input pending, unless
3013 this synchronisation check is disabled. */
3014
3015 #ifndef DISABLE_PIPE_CONNECT
3016 fl.pipe_connect_acceptable =
3017 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3018
3019 if (!check_sync())
3020 if (fl.pipe_connect_acceptable)
3021 f.smtp_in_early_pipe_used = TRUE;
3022 else
3023 #else
3024 if (!check_sync())
3025 #endif
3026 {
3027 unsigned n = smtp_inend - smtp_inptr;
3028 if (n > 32) n = 32;
3029
3030 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3031 "synchronization error (input sent without waiting for greeting): "
3032 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3033 string_printing(string_copyn(smtp_inptr, n)));
3034 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3035 return FALSE;
3036 }
3037
3038 /* Now output the banner */
3039 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3040
3041 smtp_printf("%s",
3042 #ifndef DISABLE_PIPE_CONNECT
3043 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3044 #else
3045 FALSE,
3046 #endif
3047 string_from_gstring(ss));
3048
3049 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3050 handshake arrived. If so we must have managed a TFO. */
3051
3052 #ifdef TCP_FASTOPEN
3053 tfo_in_check();
3054 #endif
3055
3056 return TRUE;
3057 }
3058
3059
3060
3061
3062
3063 /*************************************************
3064 * Handle SMTP syntax and protocol errors *
3065 *************************************************/
3066
3067 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3068 to do so. Then transmit the error response. The return value depends on the
3069 number of syntax and protocol errors in this SMTP session.
3070
3071 Arguments:
3072 type error type, given as a log flag bit
3073 code response code; <= 0 means don't send a response
3074 data data to reflect in the response (can be NULL)
3075 errmess the error message
3076
3077 Returns: -1 limit of syntax/protocol errors NOT exceeded
3078 +1 limit of syntax/protocol errors IS exceeded
3079
3080 These values fit in with the values of the "done" variable in the main
3081 processing loop in smtp_setup_msg(). */
3082
3083 static int
3084 synprot_error(int type, int code, uschar *data, uschar *errmess)
3085 {
3086 int yield = -1;
3087
3088 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3089 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3090 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3091
3092 if (++synprot_error_count > smtp_max_synprot_errors)
3093 {
3094 yield = 1;
3095 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3096 "syntax or protocol errors (last command was \"%s\")",
3097 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3098 }
3099
3100 if (code > 0)
3101 {
3102 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3103 data ? data : US"", data ? US": " : US"", errmess);
3104 if (yield == 1)
3105 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3106 }
3107
3108 return yield;
3109 }
3110
3111
3112
3113
3114 /*************************************************
3115 * Send SMTP response, possibly multiline *
3116 *************************************************/
3117
3118 /* There are, it seems, broken clients out there that cannot handle multiline
3119 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3120 output nothing for non-final calls, and only the first line for anything else.
3121
3122 Arguments:
3123 code SMTP code, may involve extended status codes
3124 codelen length of smtp code; if > 4 there's an ESC
3125 final FALSE if the last line isn't the final line
3126 msg message text, possibly containing newlines
3127
3128 Returns: nothing
3129 */
3130
3131 void
3132 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3133 {
3134 int esclen = 0;
3135 uschar *esc = US"";
3136
3137 if (!final && f.no_multiline_responses) return;
3138
3139 if (codelen > 4)
3140 {
3141 esc = code + 4;
3142 esclen = codelen - 4;
3143 }
3144
3145 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3146 have had the same. Note: this code is also present in smtp_printf(). It would
3147 be tidier to have it only in one place, but when it was added, it was easier to
3148 do it that way, so as not to have to mess with the code for the RCPT command,
3149 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3150
3151 if (fl.rcpt_in_progress)
3152 {
3153 if (rcpt_smtp_response == NULL)
3154 rcpt_smtp_response = string_copy(msg);
3155 else if (fl.rcpt_smtp_response_same &&
3156 Ustrcmp(rcpt_smtp_response, msg) != 0)
3157 fl.rcpt_smtp_response_same = FALSE;
3158 fl.rcpt_in_progress = FALSE;
3159 }
3160
3161 /* Now output the message, splitting it up into multiple lines if necessary.
3162 We only handle pipelining these responses as far as nonfinal/final groups,
3163 not the whole MAIL/RCPT/DATA response set. */
3164
3165 for (;;)
3166 {
3167 uschar *nl = Ustrchr(msg, '\n');
3168 if (nl == NULL)
3169 {
3170 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3171 return;
3172 }
3173 else if (nl[1] == 0 || f.no_multiline_responses)
3174 {
3175 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3176 (int)(nl - msg), msg);
3177 return;
3178 }
3179 else
3180 {
3181 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3182 msg = nl + 1;
3183 while (isspace(*msg)) msg++;
3184 }
3185 }
3186 }
3187
3188
3189
3190
3191 /*************************************************
3192 * Parse user SMTP message *
3193 *************************************************/
3194
3195 /* This function allows for user messages overriding the response code details
3196 by providing a suitable response code string at the start of the message
3197 user_msg. Check the message for starting with a response code and optionally an
3198 extended status code. If found, check that the first digit is valid, and if so,
3199 change the code pointer and length to use the replacement. An invalid code
3200 causes a panic log; in this case, if the log messages is the same as the user
3201 message, we must also adjust the value of the log message to show the code that
3202 is actually going to be used (the original one).
3203
3204 This function is global because it is called from receive.c as well as within
3205 this module.
3206
3207 Note that the code length returned includes the terminating whitespace
3208 character, which is always included in the regex match.
3209
3210 Arguments:
3211 code SMTP code, may involve extended status codes
3212 codelen length of smtp code; if > 4 there's an ESC
3213 msg message text
3214 log_msg optional log message, to be adjusted with the new SMTP code
3215 check_valid if true, verify the response code
3216
3217 Returns: nothing
3218 */
3219
3220 void
3221 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3222 BOOL check_valid)
3223 {
3224 int n;
3225 int ovector[3];
3226
3227 if (!msg || !*msg) return;
3228
3229 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3230 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3231
3232 if (check_valid && (*msg)[0] != (*code)[0])
3233 {
3234 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3235 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3236 if (log_msg != NULL && *log_msg == *msg)
3237 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3238 }
3239 else
3240 {
3241 *code = *msg;
3242 *codelen = ovector[1]; /* Includes final space */
3243 }
3244 *msg += ovector[1]; /* Chop the code off the message */
3245 return;
3246 }
3247
3248
3249
3250
3251 /*************************************************
3252 * Handle an ACL failure *
3253 *************************************************/
3254
3255 /* This function is called when acl_check() fails. As well as calls from within
3256 this module, it is called from receive.c for an ACL after DATA. It sorts out
3257 logging the incident, and sends the error response. A message containing
3258 newlines is turned into a multiline SMTP response, but for logging, only the
3259 first line is used.
3260
3261 There's a table of default permanent failure response codes to use in
3262 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3263 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3264 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3265 state, because there are broken clients that try VRFY before RCPT. A 5xx
3266 response should be given only when the address is positively known to be
3267 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3268 no explicit code, but if there is one we let it know best.
3269 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3270
3271 From Exim 4.63, it is possible to override the response code details by
3272 providing a suitable response code string at the start of the message provided
3273 in user_msg. The code's first digit is checked for validity.
3274
3275 Arguments:
3276 where where the ACL was called from
3277 rc the failure code
3278 user_msg a message that can be included in an SMTP response
3279 log_msg a message for logging
3280
3281 Returns: 0 in most cases
3282 2 if the failure code was FAIL_DROP, in which case the
3283 SMTP connection should be dropped (this value fits with the
3284 "done" variable in smtp_setup_msg() below)
3285 */
3286
3287 int
3288 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3289 {
3290 BOOL drop = rc == FAIL_DROP;
3291 int codelen = 3;
3292 uschar *smtp_code;
3293 uschar *lognl;
3294 uschar *sender_info = US"";
3295 uschar *what =
3296 #ifdef WITH_CONTENT_SCAN
3297 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3298 #endif
3299 where == ACL_WHERE_PREDATA ? US"DATA" :
3300 where == ACL_WHERE_DATA ? US"after DATA" :
3301 #ifndef DISABLE_PRDR
3302 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3303 #endif
3304 smtp_cmd_data ?
3305 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3306 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3307
3308 if (drop) rc = FAIL;
3309
3310 /* Set the default SMTP code, and allow a user message to change it. */
3311
3312 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3313 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3314 where != ACL_WHERE_VRFY);
3315
3316 /* We used to have sender_address here; however, there was a bug that was not
3317 updating sender_address after a rewrite during a verify. When this bug was
3318 fixed, sender_address at this point became the rewritten address. I'm not sure
3319 this is what should be logged, so I've changed to logging the unrewritten
3320 address to retain backward compatibility. */
3321
3322 #ifndef WITH_CONTENT_SCAN
3323 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3324 #else
3325 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3326 #endif
3327 {
3328 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3329 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3330 sender_host_authenticated ? US" A=" : US"",
3331 sender_host_authenticated ? sender_host_authenticated : US"",
3332 sender_host_authenticated && authenticated_id ? US":" : US"",
3333 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3334 );
3335 }
3336
3337 /* If there's been a sender verification failure with a specific message, and
3338 we have not sent a response about it yet, do so now, as a preliminary line for
3339 failures, but not defers. However, always log it for defer, and log it for fail
3340 unless the sender_verify_fail log selector has been turned off. */
3341
3342 if (sender_verified_failed &&
3343 !testflag(sender_verified_failed, af_sverify_told))
3344 {
3345 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3346 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3347
3348 setflag(sender_verified_failed, af_sverify_told);
3349
3350 if (rc != FAIL || LOGGING(sender_verify_fail))
3351 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3352 host_and_ident(TRUE),
3353 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3354 sender_verified_failed->address,
3355 (sender_verified_failed->message == NULL)? US"" :
3356 string_sprintf(": %s", sender_verified_failed->message));
3357
3358 if (rc == FAIL && sender_verified_failed->user_message)
3359 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3360 testflag(sender_verified_failed, af_verify_pmfail)?
3361 "Postmaster verification failed while checking <%s>\n%s\n"
3362 "Several RFCs state that you are required to have a postmaster\n"
3363 "mailbox for each mail domain. This host does not accept mail\n"
3364 "from domains whose servers reject the postmaster address."
3365 :
3366 testflag(sender_verified_failed, af_verify_nsfail)?
3367 "Callback setup failed while verifying <%s>\n%s\n"
3368 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3369 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3370 "RFC requirements, and stops you from receiving standard bounce\n"
3371 "messages. This host does not accept mail from domains whose servers\n"
3372 "refuse bounces."
3373 :
3374 "Verification failed for <%s>\n%s",
3375 sender_verified_failed->address,
3376 sender_verified_failed->user_message));
3377
3378 fl.rcpt_in_progress = save_rcpt_in_progress;
3379 }
3380
3381 /* Sort out text for logging */
3382
3383 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3384 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3385
3386 /* Send permanent failure response to the command, but the code used isn't
3387 always a 5xx one - see comments at the start of this function. If the original
3388 rc was FAIL_DROP we drop the connection and yield 2. */
3389
3390 if (rc == FAIL)
3391 smtp_respond(smtp_code, codelen, TRUE,
3392 user_msg ? user_msg : US"Administrative prohibition");
3393
3394 /* Send temporary failure response to the command. Don't give any details,
3395 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3396 verb, and for a header verify when smtp_return_error_details is set.
3397
3398 This conditional logic is all somewhat of a mess because of the odd
3399 interactions between temp_details and return_error_details. One day it should
3400 be re-implemented in a tidier fashion. */
3401
3402 else
3403 if (f.acl_temp_details && user_msg)
3404 {
3405 if ( smtp_return_error_details
3406 && sender_verified_failed
3407 && sender_verified_failed->message
3408 )
3409 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3410
3411 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3412 }
3413 else
3414 smtp_respond(smtp_code, codelen, TRUE,
3415 US"Temporary local problem - please try later");
3416
3417 /* Log the incident to the logs that are specified by log_reject_target
3418 (default main, reject). This can be empty to suppress logging of rejections. If
3419 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3420 is closing if required and return 2. */
3421
3422 if (log_reject_target != 0)
3423 {
3424 #ifndef DISABLE_TLS
3425 gstring * g = s_tlslog(NULL);
3426 uschar * tls = string_from_gstring(g);
3427 if (!tls) tls = US"";
3428 #else
3429 uschar * tls = US"";
3430 #endif
3431 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3432 log_reject_target, "%s%s%s %s%srejected %s%s",
3433 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3434 host_and_ident(TRUE),
3435 tls,
3436 sender_info,
3437 rc == FAIL ? US"" : US"temporarily ",
3438 what, log_msg);
3439 }
3440
3441 if (!drop) return 0;
3442
3443 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3444 smtp_get_connection_info());
3445
3446 /* Run the not-quit ACL, but without any custom messages. This should not be a
3447 problem, because we get here only if some other ACL has issued "drop", and
3448 in that case, *its* custom messages will have been used above. */
3449
3450 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3451 return 2;
3452 }
3453
3454
3455
3456
3457 /*************************************************
3458 * Handle SMTP exit when QUIT is not given *
3459 *************************************************/
3460
3461 /* This function provides a logging/statistics hook for when an SMTP connection
3462 is dropped on the floor or the other end goes away. It's a global function
3463 because it's called from receive.c as well as this module. As well as running
3464 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3465 response, either with a custom message from the ACL, or using a default. There
3466 is one case, however, when no message is output - after "drop". In that case,
3467 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3468 passed to this function.
3469
3470 In case things go wrong while processing this function, causing an error that
3471 may re-enter this function, there is a recursion check.
3472
3473 Arguments:
3474 reason What $smtp_notquit_reason will be set to in the ACL;
3475 if NULL, the ACL is not run
3476 code The error code to return as part of the response
3477 defaultrespond The default message if there's no user_msg
3478
3479 Returns: Nothing
3480 */
3481
3482 void
3483 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3484 {
3485 int rc;
3486 uschar *user_msg = NULL;
3487 uschar *log_msg = NULL;
3488
3489 /* Check for recursive call */
3490
3491 if (fl.smtp_exit_function_called)
3492 {
3493 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3494 reason);
3495 return;
3496 }
3497 fl.smtp_exit_function_called = TRUE;
3498
3499 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3500
3501 if (acl_smtp_notquit && reason)
3502 {
3503 smtp_notquit_reason = reason;
3504 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,