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