Fix dkim_verify_signers option. Bug 2366
[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 #ifdef SUPPORT_TLS
137 BOOL tls_advertised :1;
138 # ifdef EXPERIMENTAL_REQUIRETLS
139 BOOL requiretls_advertised :1;
140 # endif
141 #endif
142 BOOL dsn_advertised :1;
143 BOOL esmtp :1;
144 BOOL helo_required :1;
145 BOOL helo_verify :1;
146 BOOL helo_seen :1;
147 BOOL helo_accept_junk :1;
148 #ifdef EXPERIMENTAL_PIPE_CONNECT
149 BOOL pipe_connect_acceptable :1;
150 #endif
151 BOOL rcpt_smtp_response_same :1;
152 BOOL rcpt_in_progress :1;
153 BOOL smtp_exit_function_called :1;
154 #ifdef SUPPORT_I18N
155 BOOL smtputf8_advertised :1;
156 #endif
157 } fl = {
158 .helo_required = FALSE,
159 .helo_verify = FALSE,
160 .smtp_exit_function_called = FALSE,
161 };
162
163 static auth_instance *authenticated_by;
164 static int count_nonmail;
165 static int nonmail_command_count;
166 static int synprot_error_count;
167 static int unknown_command_count;
168 static int sync_cmd_limit;
169 static int smtp_write_error = 0;
170
171 static uschar *rcpt_smtp_response;
172 static uschar *smtp_data_buffer;
173 static uschar *smtp_cmd_data;
174
175 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
176 final fields of all except AUTH are forced TRUE at the start of a new message
177 setup, to allow one of each between messages that is not counted as a nonmail
178 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
179 allow a new EHLO after starting up TLS.
180
181 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
182 counted. However, the flag is changed when AUTH is received, so that multiple
183 failing AUTHs will eventually hit the limit. After a successful AUTH, another
184 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
185 forced TRUE, to allow for the re-authentication that can happen at that point.
186
187 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
188 count of non-mail commands and possibly provoke an error.
189
190 tls_auth is a pseudo-command, never expected in input. It is activated
191 on TLS startup and looks for a tls authenticator. */
192
193 static smtp_cmd_list cmd_list[] = {
194 /* name len cmd has_arg is_mail_cmd */
195
196 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
197 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
198 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
199 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
200 #ifdef SUPPORT_TLS
201 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
202 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
203 #endif
204
205 /* If you change anything above here, also fix the definitions below. */
206
207 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
208 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
209 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
210 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
211 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
212 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
213 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
214 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
215 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
216 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
217 };
218
219 static smtp_cmd_list *cmd_list_end =
220 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
221
222 #define CMD_LIST_RSET 0
223 #define CMD_LIST_HELO 1
224 #define CMD_LIST_EHLO 2
225 #define CMD_LIST_AUTH 3
226 #define CMD_LIST_STARTTLS 4
227 #define CMD_LIST_TLS_AUTH 5
228
229 /* This list of names is used for performing the smtp_no_mail logging action.
230 It must be kept in step with the SCH_xxx enumerations. */
231
232 static uschar *smtp_names[] =
233 {
234 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
235 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
236 US"STARTTLS", US"VRFY" };
237
238 static uschar *protocols_local[] = {
239 US"local-smtp", /* HELO */
240 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
241 US"local-esmtp", /* EHLO */
242 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
243 US"local-esmtpa", /* EHLO->AUTH */
244 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
245 };
246 static uschar *protocols[] = {
247 US"smtp", /* HELO */
248 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
249 US"esmtp", /* EHLO */
250 US"esmtps", /* EHLO->STARTTLS->EHLO */
251 US"esmtpa", /* EHLO->AUTH */
252 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
253 };
254
255 #define pnormal 0
256 #define pextend 2
257 #define pcrpted 1 /* added to pextend or pnormal */
258 #define pauthed 2 /* added to pextend */
259
260 /* Sanity check and validate optional args to MAIL FROM: envelope */
261 enum {
262 ENV_MAIL_OPT_NULL,
263 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
264 #ifndef DISABLE_PRDR
265 ENV_MAIL_OPT_PRDR,
266 #endif
267 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
268 #ifdef SUPPORT_I18N
269 ENV_MAIL_OPT_UTF8,
270 #endif
271 #ifdef EXPERIMENTAL_REQUIRETLS
272 ENV_MAIL_OPT_REQTLS,
273 #endif
274 };
275 typedef struct {
276 uschar * name; /* option requested during MAIL cmd */
277 int value; /* enum type */
278 BOOL need_value; /* TRUE requires value (name=value pair format)
279 FALSE is a singleton */
280 } env_mail_type_t;
281 static env_mail_type_t env_mail_type_list[] = {
282 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
283 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
284 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
285 #ifndef DISABLE_PRDR
286 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
287 #endif
288 { US"RET", ENV_MAIL_OPT_RET, TRUE },
289 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
290 #ifdef SUPPORT_I18N
291 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
292 #endif
293 #ifdef EXPERIMENTAL_REQUIRETLS
294 /* https://tools.ietf.org/html/draft-ietf-uta-smtp-require-tls-03 */
295 { US"REQUIRETLS",ENV_MAIL_OPT_REQTLS, FALSE },
296 #endif
297 /* keep this the last entry */
298 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
299 };
300
301 /* When reading SMTP from a remote host, we have to use our own versions of the
302 C input-reading functions, in order to be able to flush the SMTP output only
303 when about to read more data from the socket. This is the only way to get
304 optimal performance when the client is using pipelining. Flushing for every
305 command causes a separate packet and reply packet each time; saving all the
306 responses up (when pipelining) combines them into one packet and one response.
307
308 For simplicity, these functions are used for *all* SMTP input, not only when
309 receiving over a socket. However, after setting up a secure socket (SSL), input
310 is read via the OpenSSL library, and another set of functions is used instead
311 (see tls.c).
312
313 These functions are set in the receive_getc etc. variables and called with the
314 same interface as the C functions. However, since there can only ever be
315 one incoming SMTP call, we just use a single buffer and flags. There is no need
316 to implement a complicated private FILE-like structure.*/
317
318 static uschar *smtp_inbuffer;
319 static uschar *smtp_inptr;
320 static uschar *smtp_inend;
321 static int smtp_had_eof;
322 static int smtp_had_error;
323
324
325 /* forward declarations */
326 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
327 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
328 static void smtp_quit_handler(uschar **, uschar **);
329 static void smtp_rset_handler(void);
330
331 /*************************************************
332 * Recheck synchronization *
333 *************************************************/
334
335 /* Synchronization checks can never be perfect because a packet may be on its
336 way but not arrived when the check is done. Normally, the checks happen when
337 commands are read: Exim ensures that there is no more input in the input buffer.
338 In normal cases, the response to the command will be fast, and there is no
339 further check.
340
341 However, for some commands an ACL is run, and that can include delays. In those
342 cases, it is useful to do another check on the input just before sending the
343 response. This also applies at the start of a connection. This function does
344 that check by means of the select() function, as long as the facility is not
345 disabled or inappropriate. A failure of select() is ignored.
346
347 When there is unwanted input, we read it so that it appears in the log of the
348 error.
349
350 Arguments: none
351 Returns: TRUE if all is well; FALSE if there is input pending
352 */
353
354 static BOOL
355 wouldblock_reading(void)
356 {
357 int fd, rc;
358 fd_set fds;
359 struct timeval tzero;
360
361 #ifdef SUPPORT_TLS
362 if (tls_in.active.sock >= 0)
363 return !tls_could_read();
364 #endif
365
366 if (smtp_inptr < smtp_inend)
367 return FALSE;
368
369 fd = fileno(smtp_in);
370 FD_ZERO(&fds);
371 FD_SET(fd, &fds);
372 tzero.tv_sec = 0;
373 tzero.tv_usec = 0;
374 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
375
376 if (rc <= 0) return TRUE; /* Not ready to read */
377 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
378 if (rc < 0) return TRUE; /* End of file or error */
379
380 smtp_ungetc(rc);
381 return FALSE;
382 }
383
384 static BOOL
385 check_sync(void)
386 {
387 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
388 return TRUE;
389
390 return wouldblock_reading();
391 }
392
393
394 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
395 a reponse with the one following. */
396
397 static BOOL
398 pipeline_response(void)
399 {
400 if ( !smtp_enforce_sync || !sender_host_address
401 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
402 return FALSE;
403
404 if (wouldblock_reading()) return FALSE;
405 f.smtp_in_pipelining_used = TRUE;
406 return TRUE;
407 }
408
409
410 #ifdef EXPERIMENTAL_PIPE_CONNECT
411 static BOOL
412 pipeline_connect_sends(void)
413 {
414 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
415 return FALSE;
416
417 if (wouldblock_reading()) return FALSE;
418 f.smtp_in_early_pipe_used = TRUE;
419 return TRUE;
420 }
421 #endif
422
423 /*************************************************
424 * Log incomplete transactions *
425 *************************************************/
426
427 /* This function is called after a transaction has been aborted by RSET, QUIT,
428 connection drops or other errors. It logs the envelope information received
429 so far in order to preserve address verification attempts.
430
431 Argument: string to indicate what aborted the transaction
432 Returns: nothing
433 */
434
435 static void
436 incomplete_transaction_log(uschar *what)
437 {
438 if (sender_address == NULL || /* No transaction in progress */
439 !LOGGING(smtp_incomplete_transaction))
440 return;
441
442 /* Build list of recipients for logging */
443
444 if (recipients_count > 0)
445 {
446 int i;
447 raw_recipients = store_get(recipients_count * sizeof(uschar *));
448 for (i = 0; i < recipients_count; i++)
449 raw_recipients[i] = recipients_list[i].address;
450 raw_recipients_count = recipients_count;
451 }
452
453 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
454 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
455 }
456
457
458
459
460 void
461 smtp_command_timeout_exit(void)
462 {
463 log_write(L_lost_incoming_connection,
464 LOG_MAIN, "SMTP command timeout on%s connection from %s",
465 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
466 if (smtp_batched_input)
467 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
468 smtp_notquit_exit(US"command-timeout", US"421",
469 US"%s: SMTP command timeout - closing connection",
470 smtp_active_hostname);
471 exim_exit(EXIT_FAILURE, US"receiving");
472 }
473
474 void
475 smtp_command_sigterm_exit(void)
476 {
477 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
478 if (smtp_batched_input)
479 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
480 smtp_notquit_exit(US"signal-exit", US"421",
481 US"%s: Service not available - closing connection", smtp_active_hostname);
482 exim_exit(EXIT_FAILURE, US"receiving");
483 }
484
485 void
486 smtp_data_timeout_exit(void)
487 {
488 log_write(L_lost_incoming_connection,
489 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
490 sender_fullhost ? sender_fullhost : US"local process", sender_address);
491 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
492 /* Does not return */
493 }
494
495 void
496 smtp_data_sigint_exit(void)
497 {
498 log_write(0, LOG_MAIN, "%s closed after %s",
499 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
500 receive_bomb_out(US"signal-exit",
501 US"Service not available - SIGTERM or SIGINT received");
502 /* Does not return */
503 }
504
505
506
507 /* Refill the buffer, and notify DKIM verification code.
508 Return false for error or EOF.
509 */
510
511 static BOOL
512 smtp_refill(unsigned lim)
513 {
514 int rc, save_errno;
515 if (!smtp_out) return FALSE;
516 fflush(smtp_out);
517 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
518
519 /* Limit amount read, so non-message data is not fed to DKIM.
520 Take care to not touch the safety NUL at the end of the buffer. */
521
522 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
523 save_errno = errno;
524 if (smtp_receive_timeout > 0) ALARM_CLR(0);
525 if (rc <= 0)
526 {
527 /* Must put the error text in fixed store, because this might be during
528 header reading, where it releases unused store above the header. */
529 if (rc < 0)
530 {
531 if (had_command_timeout) /* set by signal handler */
532 smtp_command_timeout_exit(); /* does not return */
533 if (had_command_sigterm)
534 smtp_command_sigterm_exit();
535 if (had_data_timeout)
536 smtp_data_timeout_exit();
537 if (had_data_sigint)
538 smtp_data_sigint_exit();
539
540 smtp_had_error = save_errno;
541 smtp_read_error = string_copy_malloc(
542 string_sprintf(" (error: %s)", strerror(save_errno)));
543 }
544 else
545 smtp_had_eof = 1;
546 return FALSE;
547 }
548 #ifndef DISABLE_DKIM
549 dkim_exim_verify_feed(smtp_inbuffer, rc);
550 #endif
551 smtp_inend = smtp_inbuffer + rc;
552 smtp_inptr = smtp_inbuffer;
553 return TRUE;
554 }
555
556 /*************************************************
557 * SMTP version of getc() *
558 *************************************************/
559
560 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
561 it flushes the output, and refills the buffer, with a timeout. The signal
562 handler is set appropriately by the calling function. This function is not used
563 after a connection has negotiated itself into an TLS/SSL state.
564
565 Arguments: lim Maximum amount to read/buffer
566 Returns: the next character or EOF
567 */
568
569 int
570 smtp_getc(unsigned lim)
571 {
572 if (smtp_inptr >= smtp_inend)
573 if (!smtp_refill(lim))
574 return EOF;
575 return *smtp_inptr++;
576 }
577
578 uschar *
579 smtp_getbuf(unsigned * len)
580 {
581 unsigned size;
582 uschar * buf;
583
584 if (smtp_inptr >= smtp_inend)
585 if (!smtp_refill(*len))
586 { *len = 0; return NULL; }
587
588 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
589 buf = smtp_inptr;
590 smtp_inptr += size;
591 *len = size;
592 return buf;
593 }
594
595 void
596 smtp_get_cache(void)
597 {
598 #ifndef DISABLE_DKIM
599 int n = smtp_inend - smtp_inptr;
600 if (n > 0)
601 dkim_exim_verify_feed(smtp_inptr, n);
602 #endif
603 }
604
605
606 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
607 previous BDAT chunk and getting new ones when we run out. Uses the
608 underlying smtp_getc or tls_getc both for that and for getting the
609 (buffered) data byte. EOD signals (an expected) no further data.
610 ERR signals a protocol error, and EOF a closed input stream.
611
612 Called from read_bdat_smtp() in receive.c for the message body, but also
613 by the headers read loop in receive_msg(); manipulates chunking_state
614 to handle the BDAT command/response.
615 Placed here due to the correlation with the above smtp_getc(), which it wraps,
616 and also by the need to do smtp command/response handling.
617
618 Arguments: lim (ignored)
619 Returns: the next character or ERR, EOD or EOF
620 */
621
622 int
623 bdat_getc(unsigned lim)
624 {
625 uschar * user_msg = NULL;
626 uschar * log_msg;
627
628 for(;;)
629 {
630 #ifndef DISABLE_DKIM
631 unsigned dkim_save;
632 #endif
633
634 if (chunking_data_left > 0)
635 return lwr_receive_getc(chunking_data_left--);
636
637 receive_getc = lwr_receive_getc;
638 receive_getbuf = lwr_receive_getbuf;
639 receive_ungetc = lwr_receive_ungetc;
640 #ifndef DISABLE_DKIM
641 dkim_save = dkim_collect_input;
642 dkim_collect_input = 0;
643 #endif
644
645 /* Unless PIPELINING was offered, there should be no next command
646 until after we ack that chunk */
647
648 if (!f.smtp_in_pipelining_advertised && !check_sync())
649 {
650 unsigned n = smtp_inend - smtp_inptr;
651 if (n > 32) n = 32;
652
653 incomplete_transaction_log(US"sync failure");
654 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
655 "(next input sent too soon: pipelining was not advertised): "
656 "rejected \"%s\" %s next input=\"%s\"%s",
657 smtp_cmd_buffer, host_and_ident(TRUE),
658 string_printing(string_copyn(smtp_inptr, n)),
659 smtp_inend - smtp_inptr > n ? "..." : "");
660 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
661 US"SMTP synchronization error");
662 goto repeat_until_rset;
663 }
664
665 /* If not the last, ack the received chunk. The last response is delayed
666 until after the data ACL decides on it */
667
668 if (chunking_state == CHUNKING_LAST)
669 {
670 #ifndef DISABLE_DKIM
671 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
672 #endif
673 return EOD;
674 }
675
676 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
677 chunking_state = CHUNKING_OFFERED;
678 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
679
680 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
681 QUIT, RSET or NOOP but handling them seems obvious */
682
683 next_cmd:
684 switch(smtp_read_command(TRUE, 1))
685 {
686 default:
687 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
688 US"only BDAT permissible after non-LAST BDAT");
689
690 repeat_until_rset:
691 switch(smtp_read_command(TRUE, 1))
692 {
693 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
694 case EOF_CMD: return EOF;
695 case RSET_CMD: smtp_rset_handler(); return ERR;
696 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
697 US"only RSET accepted now") > 0)
698 return EOF;
699 goto repeat_until_rset;
700 }
701
702 case QUIT_CMD:
703 smtp_quit_handler(&user_msg, &log_msg);
704 /*FALLTHROUGH*/
705 case EOF_CMD:
706 return EOF;
707
708 case RSET_CMD:
709 smtp_rset_handler();
710 return ERR;
711
712 case NOOP_CMD:
713 HAD(SCH_NOOP);
714 smtp_printf("250 OK\r\n", FALSE);
715 goto next_cmd;
716
717 case BDAT_CMD:
718 {
719 int n;
720
721 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
722 {
723 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
724 US"missing size for BDAT command");
725 return ERR;
726 }
727 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
728 ? CHUNKING_LAST : CHUNKING_ACTIVE;
729 chunking_data_left = chunking_datasize;
730 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
731 (int)chunking_state, chunking_data_left);
732
733 if (chunking_datasize == 0)
734 if (chunking_state == CHUNKING_LAST)
735 return EOD;
736 else
737 {
738 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
739 US"zero size for BDAT command");
740 goto repeat_until_rset;
741 }
742
743 receive_getc = bdat_getc;
744 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
745 receive_ungetc = bdat_ungetc;
746 #ifndef DISABLE_DKIM
747 dkim_collect_input = dkim_save;
748 #endif
749 break; /* to top of main loop */
750 }
751 }
752 }
753 }
754
755 uschar *
756 bdat_getbuf(unsigned * len)
757 {
758 uschar * buf;
759
760 if (chunking_data_left <= 0)
761 { *len = 0; return NULL; }
762
763 if (*len > chunking_data_left) *len = chunking_data_left;
764 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
765 chunking_data_left -= *len;
766 return buf;
767 }
768
769 void
770 bdat_flush_data(void)
771 {
772 while (chunking_data_left)
773 {
774 unsigned n = chunking_data_left;
775 if (!bdat_getbuf(&n)) break;
776 }
777
778 receive_getc = lwr_receive_getc;
779 receive_getbuf = lwr_receive_getbuf;
780 receive_ungetc = lwr_receive_ungetc;
781
782 if (chunking_state != CHUNKING_LAST)
783 {
784 chunking_state = CHUNKING_OFFERED;
785 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
786 }
787 }
788
789
790
791
792 /*************************************************
793 * SMTP version of ungetc() *
794 *************************************************/
795
796 /* Puts a character back in the input buffer. Only ever
797 called once.
798
799 Arguments:
800 ch the character
801
802 Returns: the character
803 */
804
805 int
806 smtp_ungetc(int ch)
807 {
808 *--smtp_inptr = ch;
809 return ch;
810 }
811
812
813 int
814 bdat_ungetc(int ch)
815 {
816 chunking_data_left++;
817 return lwr_receive_ungetc(ch);
818 }
819
820
821
822 /*************************************************
823 * SMTP version of feof() *
824 *************************************************/
825
826 /* Tests for a previous EOF
827
828 Arguments: none
829 Returns: non-zero if the eof flag is set
830 */
831
832 int
833 smtp_feof(void)
834 {
835 return smtp_had_eof;
836 }
837
838
839
840
841 /*************************************************
842 * SMTP version of ferror() *
843 *************************************************/
844
845 /* Tests for a previous read error, and returns with errno
846 restored to what it was when the error was detected.
847
848 Arguments: none
849 Returns: non-zero if the error flag is set
850 */
851
852 int
853 smtp_ferror(void)
854 {
855 errno = smtp_had_error;
856 return smtp_had_error;
857 }
858
859
860
861 /*************************************************
862 * Test for characters in the SMTP buffer *
863 *************************************************/
864
865 /* Used at the end of a message
866
867 Arguments: none
868 Returns: TRUE/FALSE
869 */
870
871 BOOL
872 smtp_buffered(void)
873 {
874 return smtp_inptr < smtp_inend;
875 }
876
877
878
879 /*************************************************
880 * Write formatted string to SMTP channel *
881 *************************************************/
882
883 /* This is a separate function so that we don't have to repeat everything for
884 TLS support or debugging. It is global so that the daemon and the
885 authentication functions can use it. It does not return any error indication,
886 because major problems such as dropped connections won't show up till an output
887 flush for non-TLS connections. The smtp_fflush() function is available for
888 checking that: for convenience, TLS output errors are remembered here so that
889 they are also picked up later by smtp_fflush().
890
891 Arguments:
892 format format string
893 more further data expected
894 ... optional arguments
895
896 Returns: nothing
897 */
898
899 void
900 smtp_printf(const char *format, BOOL more, ...)
901 {
902 va_list ap;
903
904 va_start(ap, more);
905 smtp_vprintf(format, more, ap);
906 va_end(ap);
907 }
908
909 /* This is split off so that verify.c:respond_printf() can, in effect, call
910 smtp_printf(), bearing in mind that in C a vararg function can't directly
911 call another vararg function, only a function which accepts a va_list. */
912
913 void
914 smtp_vprintf(const char *format, BOOL more, va_list ap)
915 {
916 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
917 BOOL yield;
918
919 yield = !! string_vformat(&gs, FALSE, format, ap);
920 string_from_gstring(&gs);
921
922 DEBUG(D_receive)
923 {
924 void *reset_point = store_get(0);
925 uschar *msg_copy, *cr, *end;
926 msg_copy = string_copy(gs.s);
927 end = msg_copy + gs.ptr;
928 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
929 memmove(cr, cr + 1, (end--) - cr);
930 debug_printf("SMTP>> %s", msg_copy);
931 store_reset(reset_point);
932 }
933
934 if (!yield)
935 {
936 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
937 smtp_closedown(US"Unexpected error");
938 exim_exit(EXIT_FAILURE, NULL);
939 }
940
941 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
942 have had the same. Note: this code is also present in smtp_respond(). It would
943 be tidier to have it only in one place, but when it was added, it was easier to
944 do it that way, so as not to have to mess with the code for the RCPT command,
945 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
946
947 if (fl.rcpt_in_progress)
948 {
949 if (rcpt_smtp_response == NULL)
950 rcpt_smtp_response = string_copy(big_buffer);
951 else if (fl.rcpt_smtp_response_same &&
952 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
953 fl.rcpt_smtp_response_same = FALSE;
954 fl.rcpt_in_progress = FALSE;
955 }
956
957 /* Now write the string */
958
959 #ifdef SUPPORT_TLS
960 if (tls_in.active.sock >= 0)
961 {
962 if (tls_write(NULL, gs.s, gs.ptr, more) < 0)
963 smtp_write_error = -1;
964 }
965 else
966 #endif
967
968 if (fprintf(smtp_out, "%s", gs.s) < 0) smtp_write_error = -1;
969 }
970
971
972
973 /*************************************************
974 * Flush SMTP out and check for error *
975 *************************************************/
976
977 /* This function isn't currently used within Exim (it detects errors when it
978 tries to read the next SMTP input), but is available for use in local_scan().
979 For non-TLS connections, it flushes the output and checks for errors. For
980 TLS-connections, it checks for a previously-detected TLS write error.
981
982 Arguments: none
983 Returns: 0 for no error; -1 after an error
984 */
985
986 int
987 smtp_fflush(void)
988 {
989 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
990 return smtp_write_error;
991 }
992
993
994
995 /*************************************************
996 * SMTP command read timeout *
997 *************************************************/
998
999 /* Signal handler for timing out incoming SMTP commands. This attempts to
1000 finish off tidily.
1001
1002 Argument: signal number (SIGALRM)
1003 Returns: nothing
1004 */
1005
1006 static void
1007 command_timeout_handler(int sig)
1008 {
1009 had_command_timeout = sig;
1010 }
1011
1012
1013
1014 /*************************************************
1015 * SIGTERM received *
1016 *************************************************/
1017
1018 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1019
1020 Argument: signal number (SIGTERM)
1021 Returns: nothing
1022 */
1023
1024 static void
1025 command_sigterm_handler(int sig)
1026 {
1027 had_command_sigterm = sig;
1028 }
1029
1030
1031
1032
1033 #ifdef SUPPORT_PROXY
1034 /*************************************************
1035 * Restore socket timeout to previous value *
1036 *************************************************/
1037 /* If the previous value was successfully retrieved, restore
1038 it before returning control to the non-proxy routines
1039
1040 Arguments: fd - File descriptor for input
1041 get_ok - Successfully retrieved previous values
1042 tvtmp - Time struct with previous values
1043 vslen - Length of time struct
1044 Returns: none
1045 */
1046 static void
1047 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1048 {
1049 if (get_ok == 0)
1050 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1051 }
1052
1053 /*************************************************
1054 * Check if host is required proxy host *
1055 *************************************************/
1056 /* The function determines if inbound host will be a regular smtp host
1057 or if it is configured that it must use Proxy Protocol. A local
1058 connection cannot.
1059
1060 Arguments: none
1061 Returns: bool
1062 */
1063
1064 static BOOL
1065 check_proxy_protocol_host()
1066 {
1067 int rc;
1068
1069 if ( sender_host_address
1070 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1071 sender_host_address, NULL)) == OK)
1072 {
1073 DEBUG(D_receive)
1074 debug_printf("Detected proxy protocol configured host\n");
1075 proxy_session = TRUE;
1076 }
1077 return proxy_session;
1078 }
1079
1080
1081 /*************************************************
1082 * Read data until newline or end of buffer *
1083 *************************************************/
1084 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1085 read an entire buffer and assume there will be nothing past a proxy protocol
1086 header. Our approach normally is to use stdio, but again that relies upon
1087 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1088 reading _nothing_ before client TLS handshake. So we don't want to use the
1089 usual buffering reads which may read enough to block TLS starting.
1090
1091 So unfortunately we're down to "read one byte at a time, with a syscall each,
1092 and expect a little overhead", for all proxy-opened connections which are v1,
1093 just to handle the TLS-on-connect case. Since SSL functions wrap the
1094 underlying fd, we can't assume that we can feed them any already-read content.
1095
1096 We need to know where to read to, the max capacity, and we'll read until we
1097 get a CR and one more character. Let the caller scream if it's CR+!LF.
1098
1099 Return the amount read.
1100 */
1101
1102 static int
1103 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1104 {
1105 uschar *to = base + already;
1106 uschar *cr;
1107 int have = 0;
1108 int ret;
1109 int last = 0;
1110
1111 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1112 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1113
1114 cr = memchr(base, '\r', already);
1115 if (cr != NULL)
1116 {
1117 if ((cr - base) < already - 1)
1118 {
1119 /* \r and presumed \n already within what we have; probably not
1120 actually proxy protocol, but abort cleanly. */
1121 return 0;
1122 }
1123 /* \r is last character read, just need one more. */
1124 last = 1;
1125 }
1126
1127 while (capacity > 0)
1128 {
1129 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1130 if (ret == -1)
1131 return -1;
1132 have++;
1133 if (last)
1134 return have;
1135 if (*to == '\r')
1136 last = 1;
1137 capacity--;
1138 to++;
1139 }
1140
1141 /* reached end without having room for a final newline, abort */
1142 errno = EOVERFLOW;
1143 return -1;
1144 }
1145
1146 /*************************************************
1147 * Setup host for proxy protocol *
1148 *************************************************/
1149 /* The function configures the connection based on a header from the
1150 inbound host to use Proxy Protocol. The specification is very exact
1151 so exit with an error if do not find the exact required pieces. This
1152 includes an incorrect number of spaces separating args.
1153
1154 Arguments: none
1155 Returns: Boolean success
1156 */
1157
1158 static void
1159 setup_proxy_protocol_host()
1160 {
1161 union {
1162 struct {
1163 uschar line[108];
1164 } v1;
1165 struct {
1166 uschar sig[12];
1167 uint8_t ver_cmd;
1168 uint8_t fam;
1169 uint16_t len;
1170 union {
1171 struct { /* TCP/UDP over IPv4, len = 12 */
1172 uint32_t src_addr;
1173 uint32_t dst_addr;
1174 uint16_t src_port;
1175 uint16_t dst_port;
1176 } ip4;
1177 struct { /* TCP/UDP over IPv6, len = 36 */
1178 uint8_t src_addr[16];
1179 uint8_t dst_addr[16];
1180 uint16_t src_port;
1181 uint16_t dst_port;
1182 } ip6;
1183 struct { /* AF_UNIX sockets, len = 216 */
1184 uschar src_addr[108];
1185 uschar dst_addr[108];
1186 } unx;
1187 } addr;
1188 } v2;
1189 } hdr;
1190
1191 /* Temp variables used in PPv2 address:port parsing */
1192 uint16_t tmpport;
1193 char tmpip[INET_ADDRSTRLEN];
1194 struct sockaddr_in tmpaddr;
1195 char tmpip6[INET6_ADDRSTRLEN];
1196 struct sockaddr_in6 tmpaddr6;
1197
1198 /* We can't read "all data until end" because while SMTP is
1199 server-speaks-first, the TLS handshake is client-speaks-first, so for
1200 TLS-on-connect ports the proxy protocol header will usually be immediately
1201 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1202 reinject data for reading by those. So instead we first read "enough to be
1203 safely read within the header, and figure out how much more to read".
1204 For v1 we will later read to the end-of-line, for v2 we will read based upon
1205 the stated length.
1206
1207 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1208 data is needed total. For v1, where the line looks like:
1209 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1210
1211 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1212 We seem to support that. So, if we read 14 octets then we can tell if we're
1213 v2 or v1. If we're v1, we can continue reading as normal.
1214
1215 If we're v2, we can't slurp up the entire header. We need the length in the
1216 15th & 16th octets, then to read everything after that.
1217
1218 So to safely handle v1 and v2, with client-sent-first supported correctly,
1219 we have to do a minimum of 3 read calls, not 1. Eww.
1220 */
1221
1222 #define PROXY_INITIAL_READ 14
1223 #define PROXY_V2_HEADER_SIZE 16
1224 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1225 # error Code bug in sizes of data to read for proxy usage
1226 #endif
1227
1228 int get_ok = 0;
1229 int size, ret;
1230 int fd = fileno(smtp_in);
1231 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1232 uschar * iptype; /* To display debug info */
1233 struct timeval tv;
1234 struct timeval tvtmp;
1235 socklen_t vslen = sizeof(struct timeval);
1236 BOOL yield = FALSE;
1237
1238 /* Save current socket timeout values */
1239 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1240
1241 /* Proxy Protocol host must send header within a short time
1242 (default 3 seconds) or it's considered invalid */
1243 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1244 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1245 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1246 goto bad;
1247
1248 do
1249 {
1250 /* The inbound host was declared to be a Proxy Protocol host, so
1251 don't do a PEEK into the data, actually slurp up enough to be
1252 "safe". Can't take it all because TLS-on-connect clients follow
1253 immediately with TLS handshake. */
1254 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1255 }
1256 while (ret == -1 && errno == EINTR);
1257
1258 if (ret == -1)
1259 goto proxyfail;
1260
1261 /* For v2, handle reading the length, and then the rest. */
1262 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1263 {
1264 int retmore;
1265 uint8_t ver;
1266
1267 /* First get the length fields. */
1268 do
1269 {
1270 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1271 } while (retmore == -1 && errno == EINTR);
1272 if (retmore == -1)
1273 goto proxyfail;
1274 ret += retmore;
1275
1276 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1277
1278 /* May 2014: haproxy combined the version and command into one byte to
1279 allow two full bytes for the length field in order to proxy SSL
1280 connections. SSL Proxy is not supported in this version of Exim, but
1281 must still separate values here. */
1282
1283 if (ver != 0x02)
1284 {
1285 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1286 goto proxyfail;
1287 }
1288
1289 /* The v2 header will always be 16 bytes per the spec. */
1290 size = 16 + ntohs(hdr.v2.len);
1291 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1292 size, (int)sizeof(hdr));
1293
1294 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1295 amount that we need. Double-check that the size is not unreasonable, then
1296 get the rest. */
1297 if (size > sizeof(hdr))
1298 {
1299 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1300 goto proxyfail;
1301 }
1302
1303 do
1304 {
1305 do
1306 {
1307 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1308 } while (retmore == -1 && errno == EINTR);
1309 if (retmore == -1)
1310 goto proxyfail;
1311 ret += retmore;
1312 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1313 } while (ret < size);
1314
1315 } /* end scope for getting rest of data for v2 */
1316
1317 /* At this point: if PROXYv2, we've read the exact size required for all data;
1318 if PROXYv1 then we've read "less than required for any valid line" and should
1319 read the rest". */
1320
1321 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1322 {
1323 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1324
1325 switch (cmd)
1326 {
1327 case 0x01: /* PROXY command */
1328 switch (hdr.v2.fam)
1329 {
1330 case 0x11: /* TCPv4 address type */
1331 iptype = US"IPv4";
1332 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1333 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1334 if (!string_is_ip_address(US tmpip, NULL))
1335 {
1336 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1337 goto proxyfail;
1338 }
1339 proxy_local_address = sender_host_address;
1340 sender_host_address = string_copy(US tmpip);
1341 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1342 proxy_local_port = sender_host_port;
1343 sender_host_port = tmpport;
1344 /* Save dest ip/port */
1345 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1346 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1347 if (!string_is_ip_address(US tmpip, NULL))
1348 {
1349 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1350 goto proxyfail;
1351 }
1352 proxy_external_address = string_copy(US tmpip);
1353 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1354 proxy_external_port = tmpport;
1355 goto done;
1356 case 0x21: /* TCPv6 address type */
1357 iptype = US"IPv6";
1358 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1359 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1360 if (!string_is_ip_address(US tmpip6, NULL))
1361 {
1362 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1363 goto proxyfail;
1364 }
1365 proxy_local_address = sender_host_address;
1366 sender_host_address = string_copy(US tmpip6);
1367 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1368 proxy_local_port = sender_host_port;
1369 sender_host_port = tmpport;
1370 /* Save dest ip/port */
1371 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1372 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1373 if (!string_is_ip_address(US tmpip6, NULL))
1374 {
1375 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1376 goto proxyfail;
1377 }
1378 proxy_external_address = string_copy(US tmpip6);
1379 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1380 proxy_external_port = tmpport;
1381 goto done;
1382 default:
1383 DEBUG(D_receive)
1384 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1385 hdr.v2.fam);
1386 goto proxyfail;
1387 }
1388 /* Unsupported protocol, keep local connection address */
1389 break;
1390 case 0x00: /* LOCAL command */
1391 /* Keep local connection address for LOCAL */
1392 iptype = US"local";
1393 break;
1394 default:
1395 DEBUG(D_receive)
1396 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1397 goto proxyfail;
1398 }
1399 }
1400 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1401 {
1402 uschar *p;
1403 uschar *end;
1404 uschar *sp; /* Utility variables follow */
1405 int tmp_port;
1406 int r2;
1407 char *endc;
1408
1409 /* get the rest of the line */
1410 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1411 if (r2 == -1)
1412 goto proxyfail;
1413 ret += r2;
1414
1415 p = string_copy(hdr.v1.line);
1416 end = memchr(p, '\r', ret - 1);
1417
1418 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1419 {
1420 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1421 goto proxyfail;
1422 }
1423 *end = '\0'; /* Terminate the string */
1424 size = end + 2 - p; /* Skip header + CRLF */
1425 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1426 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1427 /* Step through the string looking for the required fields. Ensure
1428 strict adherence to required formatting, exit for any error. */
1429 p += 5;
1430 if (!isspace(*(p++)))
1431 {
1432 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1433 goto proxyfail;
1434 }
1435 if (!Ustrncmp(p, CCS"TCP4", 4))
1436 iptype = US"IPv4";
1437 else if (!Ustrncmp(p,CCS"TCP6", 4))
1438 iptype = US"IPv6";
1439 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1440 {
1441 iptype = US"Unknown";
1442 goto done;
1443 }
1444 else
1445 {
1446 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1447 goto proxyfail;
1448 }
1449
1450 p += Ustrlen(iptype);
1451 if (!isspace(*(p++)))
1452 {
1453 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1454 goto proxyfail;
1455 }
1456 /* Find the end of the arg */
1457 if ((sp = Ustrchr(p, ' ')) == NULL)
1458 {
1459 DEBUG(D_receive)
1460 debug_printf("Did not find proxied src %s\n", iptype);
1461 goto proxyfail;
1462 }
1463 *sp = '\0';
1464 if(!string_is_ip_address(p, NULL))
1465 {
1466 DEBUG(D_receive)
1467 debug_printf("Proxied src arg is not an %s address\n", iptype);
1468 goto proxyfail;
1469 }
1470 proxy_local_address = sender_host_address;
1471 sender_host_address = p;
1472 p = sp + 1;
1473 if ((sp = Ustrchr(p, ' ')) == NULL)
1474 {
1475 DEBUG(D_receive)
1476 debug_printf("Did not find proxy dest %s\n", iptype);
1477 goto proxyfail;
1478 }
1479 *sp = '\0';
1480 if(!string_is_ip_address(p, NULL))
1481 {
1482 DEBUG(D_receive)
1483 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1484 goto proxyfail;
1485 }
1486 proxy_external_address = p;
1487 p = sp + 1;
1488 if ((sp = Ustrchr(p, ' ')) == NULL)
1489 {
1490 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1491 goto proxyfail;
1492 }
1493 *sp = '\0';
1494 tmp_port = strtol(CCS p, &endc, 10);
1495 if (*endc || tmp_port == 0)
1496 {
1497 DEBUG(D_receive)
1498 debug_printf("Proxied src port '%s' not an integer\n", p);
1499 goto proxyfail;
1500 }
1501 proxy_local_port = sender_host_port;
1502 sender_host_port = tmp_port;
1503 p = sp + 1;
1504 if ((sp = Ustrchr(p, '\0')) == NULL)
1505 {
1506 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1507 goto proxyfail;
1508 }
1509 tmp_port = strtol(CCS p, &endc, 10);
1510 if (*endc || tmp_port == 0)
1511 {
1512 DEBUG(D_receive)
1513 debug_printf("Proxy dest port '%s' not an integer\n", p);
1514 goto proxyfail;
1515 }
1516 proxy_external_port = tmp_port;
1517 /* Already checked for /r /n above. Good V1 header received. */
1518 }
1519 else
1520 {
1521 /* Wrong protocol */
1522 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1523 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1524 goto proxyfail;
1525 }
1526
1527 done:
1528 DEBUG(D_receive)
1529 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1530 yield = proxy_session;
1531
1532 /* Don't flush any potential buffer contents. Any input on proxyfail
1533 should cause a synchronization failure */
1534
1535 proxyfail:
1536 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1537
1538 bad:
1539 if (yield)
1540 {
1541 sender_host_name = NULL;
1542 (void) host_name_lookup();
1543 host_build_sender_fullhost();
1544 }
1545 else
1546 {
1547 f.proxy_session_failed = TRUE;
1548 DEBUG(D_receive)
1549 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1550 }
1551
1552 return;
1553 }
1554 #endif
1555
1556 /*************************************************
1557 * Read one command line *
1558 *************************************************/
1559
1560 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1561 There are sites that don't do this, and in any case internal SMTP probably
1562 should check only for LF. Consequently, we check here for LF only. The line
1563 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1564 an unknown command. The command is read into the global smtp_cmd_buffer so that
1565 it is available via $smtp_command.
1566
1567 The character reading routine sets up a timeout for each block actually read
1568 from the input (which may contain more than one command). We set up a special
1569 signal handler that closes down the session on a timeout. Control does not
1570 return when it runs.
1571
1572 Arguments:
1573 check_sync if TRUE, check synchronization rules if global option is TRUE
1574 buffer_lim maximum to buffer in lower layer
1575
1576 Returns: a code identifying the command (enumerated above)
1577 */
1578
1579 static int
1580 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1581 {
1582 int c;
1583 int ptr = 0;
1584 smtp_cmd_list *p;
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 (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 #ifdef SUPPORT_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 g = string_append(g, 2, US" X=", tls_in.cipher);
1802 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1803 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1804 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1805 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1806 if (LOGGING(tls_sni) && tls_in.sni)
1807 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1808 return g;
1809 }
1810 #endif
1811
1812 /*************************************************
1813 * Log lack of MAIL if so configured *
1814 *************************************************/
1815
1816 /* This function is called when an SMTP session ends. If the log selector
1817 smtp_no_mail is set, write a log line giving some details of what has happened
1818 in the SMTP session.
1819
1820 Arguments: none
1821 Returns: nothing
1822 */
1823
1824 void
1825 smtp_log_no_mail(void)
1826 {
1827 int i;
1828 uschar * sep, * s;
1829 gstring * g = NULL;
1830
1831 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1832 return;
1833
1834 if (sender_host_authenticated)
1835 {
1836 g = string_append(g, 2, US" A=", sender_host_authenticated);
1837 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1838 }
1839
1840 #ifdef SUPPORT_TLS
1841 g = s_tlslog(g);
1842 #endif
1843
1844 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1845
1846 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1847 if (smtp_connection_had[i] != SCH_NONE)
1848 {
1849 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1850 sep = US",";
1851 }
1852
1853 for (i = 0; i < smtp_ch_index; i++)
1854 {
1855 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1856 sep = US",";
1857 }
1858
1859 if (!(s = string_from_gstring(g))) s = US"";
1860
1861 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1862 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1863 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1864 }
1865
1866
1867 /* Return list of recent smtp commands */
1868
1869 uschar *
1870 smtp_cmd_hist(void)
1871 {
1872 int i;
1873 gstring * list = NULL;
1874 uschar * s;
1875
1876 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1877 if (smtp_connection_had[i] != SCH_NONE)
1878 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1879
1880 for (i = 0; i < smtp_ch_index; i++)
1881 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1882
1883 s = string_from_gstring(list);
1884 return s ? s : US"";
1885 }
1886
1887
1888
1889
1890 /*************************************************
1891 * Check HELO line and set sender_helo_name *
1892 *************************************************/
1893
1894 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1895 the domain name of the sending host, or an ip literal in square brackets. The
1896 argument is placed in sender_helo_name, which is in malloc store, because it
1897 must persist over multiple incoming messages. If helo_accept_junk is set, this
1898 host is permitted to send any old junk (needed for some broken hosts).
1899 Otherwise, helo_allow_chars can be used for rogue characters in general
1900 (typically people want to let in underscores).
1901
1902 Argument:
1903 s the data portion of the line (already past any white space)
1904
1905 Returns: TRUE or FALSE
1906 */
1907
1908 static BOOL
1909 check_helo(uschar *s)
1910 {
1911 uschar *start = s;
1912 uschar *end = s + Ustrlen(s);
1913 BOOL yield = fl.helo_accept_junk;
1914
1915 /* Discard any previous helo name */
1916
1917 if (sender_helo_name)
1918 {
1919 store_free(sender_helo_name);
1920 sender_helo_name = NULL;
1921 }
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_malloc(start);
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 EXPERIMENTAL_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 #endif
2096 dsn_ret = 0;
2097 dsn_envid = NULL;
2098 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2099 #ifndef DISABLE_PRDR
2100 prdr_requested = FALSE;
2101 #endif
2102 #ifdef SUPPORT_I18N
2103 message_smtputf8 = FALSE;
2104 #endif
2105 body_linecount = body_zerocount = 0;
2106
2107 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2108 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2109 /* Note that ratelimiters_conn persists across resets. */
2110
2111 /* Reset message ACL variables */
2112
2113 acl_var_m = NULL;
2114
2115 /* The message body variables use malloc store. They may be set if this is
2116 not the first message in an SMTP session and the previous message caused them
2117 to be referenced in an ACL. */
2118
2119 if (message_body)
2120 {
2121 store_free(message_body);
2122 message_body = NULL;
2123 }
2124
2125 if (message_body_end)
2126 {
2127 store_free(message_body_end);
2128 message_body_end = NULL;
2129 }
2130
2131 /* Warning log messages are also saved in malloc store. They are saved to avoid
2132 repetition in the same message, but it seems right to repeat them for different
2133 messages. */
2134
2135 while (acl_warn_logged)
2136 {
2137 string_item *this = acl_warn_logged;
2138 acl_warn_logged = acl_warn_logged->next;
2139 store_free(this);
2140 }
2141 store_reset(reset_point);
2142 }
2143
2144
2145
2146
2147
2148 /*************************************************
2149 * Initialize for incoming batched SMTP message *
2150 *************************************************/
2151
2152 /* This function is called from smtp_setup_msg() in the case when
2153 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2154 of messages in one file with SMTP commands between them. All errors must be
2155 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2156 relevant. After an error on a sender, or an invalid recipient, the remainder
2157 of the message is skipped. The value of received_protocol is already set.
2158
2159 Argument: none
2160 Returns: > 0 message successfully started (reached DATA)
2161 = 0 QUIT read or end of file reached
2162 < 0 should not occur
2163 */
2164
2165 static int
2166 smtp_setup_batch_msg(void)
2167 {
2168 int done = 0;
2169 void *reset_point = store_get(0);
2170
2171 /* Save the line count at the start of each transaction - single commands
2172 like HELO and RSET count as whole transactions. */
2173
2174 bsmtp_transaction_linecount = receive_linecount;
2175
2176 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2177
2178 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2179 smtp_reset(reset_point); /* Reset for start of message */
2180
2181 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2182 value. The values are 2 larger than the required yield of the function. */
2183
2184 while (done <= 0)
2185 {
2186 uschar *errmess;
2187 uschar *recipient = NULL;
2188 int start, end, sender_domain, recipient_domain;
2189
2190 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2191 {
2192 /* The HELO/EHLO commands set sender_address_helo if they have
2193 valid data; otherwise they are ignored, except that they do
2194 a reset of the state. */
2195
2196 case HELO_CMD:
2197 case EHLO_CMD:
2198
2199 check_helo(smtp_cmd_data);
2200 /* Fall through */
2201
2202 case RSET_CMD:
2203 cancel_cutthrough_connection(TRUE, US"RSET received");
2204 smtp_reset(reset_point);
2205 bsmtp_transaction_linecount = receive_linecount;
2206 break;
2207
2208
2209 /* The MAIL FROM command requires an address as an operand. All we
2210 do here is to parse it for syntactic correctness. The form "<>" is
2211 a special case which converts into an empty string. The start/end
2212 pointers in the original are not used further for this address, as
2213 it is the canonical extracted address which is all that is kept. */
2214
2215 case MAIL_CMD:
2216 smtp_mailcmd_count++; /* Count for no-mail log */
2217 if (sender_address != NULL)
2218 /* The function moan_smtp_batch() does not return. */
2219 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2220
2221 if (smtp_cmd_data[0] == 0)
2222 /* The function moan_smtp_batch() does not return. */
2223 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2224
2225 /* Reset to start of message */
2226
2227 cancel_cutthrough_connection(TRUE, US"MAIL received");
2228 smtp_reset(reset_point);
2229
2230 /* Apply SMTP rewrite */
2231
2232 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2233 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2234 US"", global_rewrite_rules) : smtp_cmd_data;
2235
2236 /* Extract the address; the TRUE flag allows <> as valid */
2237
2238 raw_sender =
2239 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2240 TRUE);
2241
2242 if (!raw_sender)
2243 /* The function moan_smtp_batch() does not return. */
2244 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2245
2246 sender_address = string_copy(raw_sender);
2247
2248 /* Qualify unqualified sender addresses if permitted to do so. */
2249
2250 if ( !sender_domain
2251 && sender_address[0] != 0 && sender_address[0] != '@')
2252 if (f.allow_unqualified_sender)
2253 {
2254 sender_address = rewrite_address_qualify(sender_address, FALSE);
2255 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2256 "and rewritten\n", raw_sender);
2257 }
2258 /* The function moan_smtp_batch() does not return. */
2259 else
2260 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2261 "a domain");
2262 break;
2263
2264
2265 /* The RCPT TO command requires an address as an operand. All we do
2266 here is to parse it for syntactic correctness. There may be any number
2267 of RCPT TO commands, specifying multiple senders. We build them all into
2268 a data structure that is in argc/argv format. The start/end values
2269 given by parse_extract_address are not used, as we keep only the
2270 extracted address. */
2271
2272 case RCPT_CMD:
2273 if (!sender_address)
2274 /* The function moan_smtp_batch() does not return. */
2275 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2276
2277 if (smtp_cmd_data[0] == 0)
2278 /* The function moan_smtp_batch() does not return. */
2279 moan_smtp_batch(smtp_cmd_buffer,
2280 "501 RCPT TO must have an address operand");
2281
2282 /* Check maximum number allowed */
2283
2284 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2285 /* The function moan_smtp_batch() does not return. */
2286 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2287 recipients_max_reject? "552": "452");
2288
2289 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2290 recipient address */
2291
2292 recipient = rewrite_existflags & rewrite_smtp
2293 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2294 global_rewrite_rules)
2295 : smtp_cmd_data;
2296
2297 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2298 &recipient_domain, FALSE);
2299
2300 if (!recipient)
2301 /* The function moan_smtp_batch() does not return. */
2302 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2303
2304 /* If the recipient address is unqualified, qualify it if permitted. Then
2305 add it to the list of recipients. */
2306
2307 if (!recipient_domain)
2308 if (f.allow_unqualified_recipient)
2309 {
2310 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2311 recipient);
2312 recipient = rewrite_address_qualify(recipient, TRUE);
2313 }
2314 /* The function moan_smtp_batch() does not return. */
2315 else
2316 moan_smtp_batch(smtp_cmd_buffer,
2317 "501 recipient address must contain a domain");
2318
2319 receive_add_recipient(recipient, -1);
2320 break;
2321
2322
2323 /* The DATA command is legal only if it follows successful MAIL FROM
2324 and RCPT TO commands. This function is complete when a valid DATA
2325 command is encountered. */
2326
2327 case DATA_CMD:
2328 if (!sender_address || recipients_count <= 0)
2329 /* The function moan_smtp_batch() does not return. */
2330 if (!sender_address)
2331 moan_smtp_batch(smtp_cmd_buffer,
2332 "503 MAIL FROM:<sender> command must precede DATA");
2333 else
2334 moan_smtp_batch(smtp_cmd_buffer,
2335 "503 RCPT TO:<recipient> must precede DATA");
2336 else
2337 {
2338 done = 3; /* DATA successfully achieved */
2339 message_ended = END_NOTENDED; /* Indicate in middle of message */
2340 }
2341 break;
2342
2343
2344 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2345
2346 case VRFY_CMD:
2347 case EXPN_CMD:
2348 case HELP_CMD:
2349 case NOOP_CMD:
2350 case ETRN_CMD:
2351 bsmtp_transaction_linecount = receive_linecount;
2352 break;
2353
2354
2355 case EOF_CMD:
2356 case QUIT_CMD:
2357 done = 2;
2358 break;
2359
2360
2361 case BADARG_CMD:
2362 /* The function moan_smtp_batch() does not return. */
2363 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2364 break;
2365
2366
2367 case BADCHAR_CMD:
2368 /* The function moan_smtp_batch() does not return. */
2369 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2370 break;
2371
2372
2373 default:
2374 /* The function moan_smtp_batch() does not return. */
2375 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2376 break;
2377 }
2378 }
2379
2380 return done - 2; /* Convert yield values */
2381 }
2382
2383
2384
2385
2386 #ifdef SUPPORT_TLS
2387 static BOOL
2388 smtp_log_tls_fail(uschar * errstr)
2389 {
2390 uschar * conn_info = smtp_get_connection_info();
2391
2392 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2393 /* I'd like to get separated H= here, but too hard for now */
2394
2395 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2396 return FALSE;
2397 }
2398 #endif
2399
2400
2401
2402
2403 #ifdef TCP_FASTOPEN
2404 static void
2405 tfo_in_check(void)
2406 {
2407 # ifdef TCP_INFO
2408 struct tcp_info tinfo;
2409 socklen_t len = sizeof(tinfo);
2410
2411 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2412 #ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11 does not seem to have this yet */
2413 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2414 {
2415 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (ACKd data-on-SYN)\n");
2416 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2417 }
2418 else
2419 #endif
2420 if (tinfo.tcpi_state == TCP_SYN_RECV)
2421 {
2422 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2423 f.tcp_in_fastopen = TRUE;
2424 }
2425 # endif
2426 }
2427 #endif
2428
2429
2430 /*************************************************
2431 * Start an SMTP session *
2432 *************************************************/
2433
2434 /* This function is called at the start of an SMTP session. Thereafter,
2435 smtp_setup_msg() is called to initiate each separate message. This
2436 function does host-specific testing, and outputs the banner line.
2437
2438 Arguments: none
2439 Returns: FALSE if the session can not continue; something has
2440 gone wrong, or the connection to the host is blocked
2441 */
2442
2443 BOOL
2444 smtp_start_session(void)
2445 {
2446 int esclen;
2447 uschar *user_msg, *log_msg;
2448 uschar *code, *esc;
2449 uschar *p, *s;
2450 gstring * ss;
2451
2452 gettimeofday(&smtp_connection_start, NULL);
2453 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2454 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2455 smtp_ch_index = 0;
2456
2457 /* Default values for certain variables */
2458
2459 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2460 smtp_mailcmd_count = 0;
2461 count_nonmail = TRUE_UNSET;
2462 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2463 smtp_delay_mail = smtp_rlm_base;
2464 fl.auth_advertised = FALSE;
2465 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2466 f.pipelining_enable = TRUE;
2467 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2468 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2469
2470 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2471 authentication settings from -oMaa to remain in force. */
2472
2473 if (!host_checking && !f.sender_host_notsocket)
2474 sender_host_auth_pubname = sender_host_authenticated = NULL;
2475 authenticated_by = NULL;
2476
2477 #ifdef SUPPORT_TLS
2478 tls_in.cipher = tls_in.peerdn = NULL;
2479 tls_in.ourcert = tls_in.peercert = NULL;
2480 tls_in.sni = NULL;
2481 tls_in.ocsp = OCSP_NOT_REQ;
2482 fl.tls_advertised = FALSE;
2483 # ifdef EXPERIMENTAL_REQUIRETLS
2484 fl.requiretls_advertised = FALSE;
2485 # endif
2486 #endif
2487 fl.dsn_advertised = FALSE;
2488 #ifdef SUPPORT_I18N
2489 fl.smtputf8_advertised = FALSE;
2490 #endif
2491
2492 /* Reset ACL connection variables */
2493
2494 acl_var_c = NULL;
2495
2496 /* Allow for trailing 0 in the command and data buffers. */
2497
2498 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2499 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2500 "malloc() failed for SMTP command buffer");
2501
2502 smtp_cmd_buffer[0] = 0;
2503 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2504
2505 /* For batched input, the protocol setting can be overridden from the
2506 command line by a trusted caller. */
2507
2508 if (smtp_batched_input)
2509 {
2510 if (!received_protocol) received_protocol = US"local-bsmtp";
2511 }
2512
2513 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2514 reset later if any of EHLO/AUTH/STARTTLS are received. */
2515
2516 else
2517 received_protocol =
2518 (sender_host_address ? protocols : protocols_local) [pnormal];
2519
2520 /* Set up the buffer for inputting using direct read() calls, and arrange to
2521 call the local functions instead of the standard C ones. Place a NUL at the
2522 end of the buffer to safety-stop C-string reads from it. */
2523
2524 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2525 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2526 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2527
2528 receive_getc = smtp_getc;
2529 receive_getbuf = smtp_getbuf;
2530 receive_get_cache = smtp_get_cache;
2531 receive_ungetc = smtp_ungetc;
2532 receive_feof = smtp_feof;
2533 receive_ferror = smtp_ferror;
2534 receive_smtp_buffered = smtp_buffered;
2535 smtp_inptr = smtp_inend = smtp_inbuffer;
2536 smtp_had_eof = smtp_had_error = 0;
2537
2538 /* Set up the message size limit; this may be host-specific */
2539
2540 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2541 if (expand_string_message)
2542 {
2543 if (thismessage_size_limit == -1)
2544 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2545 "%s", expand_string_message);
2546 else
2547 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2548 "%s", expand_string_message);
2549 smtp_closedown(US"Temporary local problem - please try later");
2550 return FALSE;
2551 }
2552
2553 /* When a message is input locally via the -bs or -bS options, sender_host_
2554 unknown is set unless -oMa was used to force an IP address, in which case it
2555 is checked like a real remote connection. When -bs is used from inetd, this
2556 flag is not set, causing the sending host to be checked. The code that deals
2557 with IP source routing (if configured) is never required for -bs or -bS and
2558 the flag sender_host_notsocket is used to suppress it.
2559
2560 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2561 reserve for certain hosts and/or networks. */
2562
2563 if (!f.sender_host_unknown)
2564 {
2565 int rc;
2566 BOOL reserved_host = FALSE;
2567
2568 /* Look up IP options (source routing info) on the socket if this is not an
2569 -oMa "host", and if any are found, log them and drop the connection.
2570
2571 Linux (and others now, see below) is different to everyone else, so there
2572 has to be some conditional compilation here. Versions of Linux before 2.1.15
2573 used a structure whose name was "options". Somebody finally realized that
2574 this name was silly, and it got changed to "ip_options". I use the
2575 newer name here, but there is a fudge in the script that sets up os.h
2576 to define a macro in older Linux systems.
2577
2578 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2579 glibc 2, which has chosen ip_opts for the structure name. This is now
2580 really a glibc thing rather than a Linux thing, so the condition name
2581 has been changed to reflect this. It is relevant also to GNU/Hurd.
2582
2583 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2584 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2585 a special macro defined in the os.h file.
2586
2587 Some DGUX versions on older hardware appear not to support IP options at
2588 all, so there is now a general macro which can be set to cut out this
2589 support altogether.
2590
2591 How to do this properly in IPv6 is not yet known. */
2592
2593 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2594
2595 #ifdef GLIBC_IP_OPTIONS
2596 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2597 #define OPTSTYLE 1
2598 #else
2599 #define OPTSTYLE 2
2600 #endif
2601 #elif defined DARWIN_IP_OPTIONS
2602 #define OPTSTYLE 2
2603 #else
2604 #define OPTSTYLE 3
2605 #endif
2606
2607 if (!host_checking && !f.sender_host_notsocket)
2608 {
2609 #if OPTSTYLE == 1
2610 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2611 struct ip_options *ipopt = store_get(optlen);
2612 #elif OPTSTYLE == 2
2613 struct ip_opts ipoptblock;
2614 struct ip_opts *ipopt = &ipoptblock;
2615 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2616 #else
2617 struct ipoption ipoptblock;
2618 struct ipoption *ipopt = &ipoptblock;
2619 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2620 #endif
2621
2622 /* Occasional genuine failures of getsockopt() have been seen - for
2623 example, "reset by peer". Therefore, just log and give up on this
2624 call, unless the error is ENOPROTOOPT. This error is given by systems
2625 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2626 of writing. So for that error, carry on - we just can't do an IP options
2627 check. */
2628
2629 DEBUG(D_receive) debug_printf("checking for IP options\n");
2630
2631 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2632 &optlen) < 0)
2633 {
2634 if (errno != ENOPROTOOPT)
2635 {
2636 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2637 host_and_ident(FALSE), strerror(errno));
2638 smtp_printf("451 SMTP service not available\r\n", FALSE);
2639 return FALSE;
2640 }
2641 }
2642
2643 /* Deal with any IP options that are set. On the systems I have looked at,
2644 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2645 more logging data than will fit in big_buffer. Nevertheless, after somebody
2646 questioned this code, I've added in some paranoid checking. */
2647
2648 else if (optlen > 0)
2649 {
2650 uschar *p = big_buffer;
2651 uschar *pend = big_buffer + big_buffer_size;
2652 uschar *opt, *adptr;
2653 int optcount;
2654 struct in_addr addr;
2655
2656 #if OPTSTYLE == 1
2657 uschar *optstart = US (ipopt->__data);
2658 #elif OPTSTYLE == 2
2659 uschar *optstart = US (ipopt->ip_opts);
2660 #else
2661 uschar *optstart = US (ipopt->ipopt_list);
2662 #endif
2663
2664 DEBUG(D_receive) debug_printf("IP options exist\n");
2665
2666 Ustrcpy(p, "IP options on incoming call:");
2667 p += Ustrlen(p);
2668
2669 for (opt = optstart; opt != NULL &&
2670 opt < US (ipopt) + optlen;)
2671 {
2672 switch (*opt)
2673 {
2674 case IPOPT_EOL:
2675 opt = NULL;
2676 break;
2677
2678 case IPOPT_NOP:
2679 opt++;
2680 break;
2681
2682 case IPOPT_SSRR:
2683 case IPOPT_LSRR:
2684 if (!string_format(p, pend-p, " %s [@%s",
2685 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2686 #if OPTSTYLE == 1
2687 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2688 #elif OPTSTYLE == 2
2689 inet_ntoa(ipopt->ip_dst)))
2690 #else
2691 inet_ntoa(ipopt->ipopt_dst)))
2692 #endif
2693 {
2694 opt = NULL;
2695 break;
2696 }
2697
2698 p += Ustrlen(p);
2699 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2700 adptr = opt + 3;
2701 while (optcount-- > 0)
2702 {
2703 memcpy(&addr, adptr, sizeof(addr));
2704 if (!string_format(p, pend - p - 1, "%s%s",
2705 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2706 {
2707 opt = NULL;
2708 break;
2709 }
2710 p += Ustrlen(p);
2711 adptr += sizeof(struct in_addr);
2712 }
2713 *p++ = ']';
2714 opt += opt[1];
2715 break;
2716
2717 default:
2718 {
2719 int i;
2720 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2721 Ustrcat(p, "[ ");
2722 p += 2;
2723 for (i = 0; i < opt[1]; i++)
2724 p += sprintf(CS p, "%2.2x ", opt[i]);
2725 *p++ = ']';
2726 }
2727 opt += opt[1];
2728 break;
2729 }
2730 }
2731
2732 *p = 0;
2733 log_write(0, LOG_MAIN, "%s", big_buffer);
2734
2735 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2736
2737 log_write(0, LOG_MAIN|LOG_REJECT,
2738 "connection from %s refused (IP options)", host_and_ident(FALSE));
2739
2740 smtp_printf("554 SMTP service not available\r\n", FALSE);
2741 return FALSE;
2742 }
2743
2744 /* Length of options = 0 => there are no options */
2745
2746 else DEBUG(D_receive) debug_printf("no IP options found\n");
2747 }
2748 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2749
2750 /* Set keep-alive in socket options. The option is on by default. This
2751 setting is an attempt to get rid of some hanging connections that stick in
2752 read() when the remote end (usually a dialup) goes away. */
2753
2754 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2755 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2756
2757 /* If the current host matches host_lookup, set the name by doing a
2758 reverse lookup. On failure, sender_host_name will be NULL and
2759 host_lookup_failed will be TRUE. This may or may not be serious - optional
2760 checks later. */
2761
2762 if (verify_check_host(&host_lookup) == OK)
2763 {
2764 (void)host_name_lookup();
2765 host_build_sender_fullhost();
2766 }
2767
2768 /* Delay this until we have the full name, if it is looked up. */
2769
2770 set_process_info("handling incoming connection from %s",
2771 host_and_ident(FALSE));
2772
2773 /* Expand smtp_receive_timeout, if needed */
2774
2775 if (smtp_receive_timeout_s)
2776 {
2777 uschar * exp;
2778 if ( !(exp = expand_string(smtp_receive_timeout_s))
2779 || !(*exp)
2780 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2781 )
2782 log_write(0, LOG_MAIN|LOG_PANIC,
2783 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2784 }
2785
2786 /* Test for explicit connection rejection */
2787
2788 if (verify_check_host(&host_reject_connection) == OK)
2789 {
2790 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2791 "from %s (host_reject_connection)", host_and_ident(FALSE));
2792 smtp_printf("554 SMTP service not available\r\n", FALSE);
2793 return FALSE;
2794 }
2795
2796 /* Test with TCP Wrappers if so configured. There is a problem in that
2797 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2798 such as disks dying. In these cases, it is desirable to reject with a 4xx
2799 error instead of a 5xx error. There isn't a "right" way to detect such
2800 problems. The following kludge is used: errno is zeroed before calling
2801 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2802 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2803 not exist). */
2804
2805 #ifdef USE_TCP_WRAPPERS
2806 errno = 0;
2807 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2808 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2809 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2810 expand_string_message);
2811
2812 if (!hosts_ctl(tcp_wrappers_name,
2813 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2814 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2815 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2816 {
2817 if (errno == 0 || errno == ENOENT)
2818 {
2819 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2820 log_write(L_connection_reject,
2821 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2822 "(tcp wrappers)", host_and_ident(FALSE));
2823 smtp_printf("554 SMTP service not available\r\n", FALSE);
2824 }
2825 else
2826 {
2827 int save_errno = errno;
2828 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2829 "errno value %d\n", save_errno);
2830 log_write(L_connection_reject,
2831 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2832 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2833 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2834 }
2835 return FALSE;
2836 }
2837 #endif
2838
2839 /* Check for reserved slots. The value of smtp_accept_count has already been
2840 incremented to include this process. */
2841
2842 if (smtp_accept_max > 0 &&
2843 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2844 {
2845 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2846 {
2847 log_write(L_connection_reject,
2848 LOG_MAIN, "temporarily refused connection from %s: not in "
2849 "reserve list: connected=%d max=%d reserve=%d%s",
2850 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2851 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2852 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2853 "please try again later\r\n", FALSE, smtp_active_hostname);
2854 return FALSE;
2855 }
2856 reserved_host = TRUE;
2857 }
2858
2859 /* If a load level above which only messages from reserved hosts are
2860 accepted is set, check the load. For incoming calls via the daemon, the
2861 check is done in the superior process if there are no reserved hosts, to
2862 save a fork. In all cases, the load average will already be available
2863 in a global variable at this point. */
2864
2865 if (smtp_load_reserve >= 0 &&
2866 load_average > smtp_load_reserve &&
2867 !reserved_host &&
2868 verify_check_host(&smtp_reserve_hosts) != OK)
2869 {
2870 log_write(L_connection_reject,
2871 LOG_MAIN, "temporarily refused connection from %s: not in "
2872 "reserve list and load average = %.2f", host_and_ident(FALSE),
2873 (double)load_average/1000.0);
2874 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2875 smtp_active_hostname);
2876 return FALSE;
2877 }
2878
2879 /* Determine whether unqualified senders or recipients are permitted
2880 for this host. Unfortunately, we have to do this every time, in order to
2881 set the flags so that they can be inspected when considering qualifying
2882 addresses in the headers. For a site that permits no qualification, this
2883 won't take long, however. */
2884
2885 f.allow_unqualified_sender =
2886 verify_check_host(&sender_unqualified_hosts) == OK;
2887
2888 f.allow_unqualified_recipient =
2889 verify_check_host(&recipient_unqualified_hosts) == OK;
2890
2891 /* Determine whether HELO/EHLO is required for this host. The requirement
2892 can be hard or soft. */
2893
2894 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2895 if (!fl.helo_required)
2896 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2897
2898 /* Determine whether this hosts is permitted to send syntactic junk
2899 after a HELO or EHLO command. */
2900
2901 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2902 }
2903
2904 /* For batch SMTP input we are now done. */
2905
2906 if (smtp_batched_input) return TRUE;
2907
2908 /* If valid Proxy Protocol source is connecting, set up session.
2909 * Failure will not allow any SMTP function other than QUIT. */
2910
2911 #ifdef SUPPORT_PROXY
2912 proxy_session = FALSE;
2913 f.proxy_session_failed = FALSE;
2914 if (check_proxy_protocol_host())
2915 setup_proxy_protocol_host();
2916 #endif
2917
2918 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2919 smtps port for use with older style SSL MTAs. */
2920
2921 #ifdef SUPPORT_TLS
2922 if (tls_in.on_connect)
2923 {
2924 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2925 return smtp_log_tls_fail(user_msg);
2926 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2927 }
2928 #endif
2929
2930 /* Run the connect ACL if it exists */
2931
2932 user_msg = NULL;
2933 if (acl_smtp_connect)
2934 {
2935 int rc;
2936 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2937 &log_msg)) != OK)
2938 {
2939 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2940 return FALSE;
2941 }
2942 }
2943
2944 /* Output the initial message for a two-way SMTP connection. It may contain
2945 newlines, which then cause a multi-line response to be given. */
2946
2947 code = US"220"; /* Default status code */
2948 esc = US""; /* Default extended status code */
2949 esclen = 0; /* Length of esc */
2950
2951 if (!user_msg)
2952 {
2953 if (!(s = expand_string(smtp_banner)))
2954 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2955 "failed: %s", smtp_banner, expand_string_message);
2956 }
2957 else
2958 {
2959 int codelen = 3;
2960 s = user_msg;
2961 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2962 if (codelen > 4)
2963 {
2964 esc = code + 4;
2965 esclen = codelen - 4;
2966 }
2967 }
2968
2969 /* Remove any terminating newlines; might as well remove trailing space too */
2970
2971 p = s + Ustrlen(s);
2972 while (p > s && isspace(p[-1])) p--;
2973 *p = 0;
2974
2975 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2976 is all contained in a single IP packet. The original code wrote out the
2977 greeting using several calls to fprint/fputc, and on busy servers this could
2978 cause it to be split over more than one packet - which caused CC:Mail to fall
2979 over when it got the second part of the greeting after sending its first
2980 command. Sigh. To try to avoid this, build the complete greeting message
2981 first, and output it in one fell swoop. This gives a better chance of it
2982 ending up as a single packet. */
2983
2984 ss = string_get(256);
2985
2986 p = s;
2987 do /* At least once, in case we have an empty string */
2988 {
2989 int len;
2990 uschar *linebreak = Ustrchr(p, '\n');
2991 ss = string_catn(ss, code, 3);
2992 if (!linebreak)
2993 {
2994 len = Ustrlen(p);
2995 ss = string_catn(ss, US" ", 1);
2996 }
2997 else
2998 {
2999 len = linebreak - p;
3000 ss = string_catn(ss, US"-", 1);
3001 }
3002 ss = string_catn(ss, esc, esclen);
3003 ss = string_catn(ss, p, len);
3004 ss = string_catn(ss, US"\r\n", 2);
3005 p += len;
3006 if (linebreak) p++;
3007 }
3008 while (*p);
3009
3010 /* Before we write the banner, check that there is no input pending, unless
3011 this synchronisation check is disabled. */
3012
3013 #ifdef EXPERIMENTAL_PIPE_CONNECT
3014 fl.pipe_connect_acceptable =
3015 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3016
3017 if (!check_sync())
3018 if (fl.pipe_connect_acceptable)
3019 f.smtp_in_early_pipe_used = TRUE;
3020 else
3021 #else
3022 if (!check_sync())
3023 #endif
3024 {
3025 unsigned n = smtp_inend - smtp_inptr;
3026 if (n > 32) n = 32;
3027
3028 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3029 "synchronization error (input sent without waiting for greeting): "
3030 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3031 string_printing(string_copyn(smtp_inptr, n)));
3032 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3033 return FALSE;
3034 }
3035
3036 /* Now output the banner */
3037 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3038
3039 smtp_printf("%s",
3040 #ifdef EXPERIMENTAL_PIPE_CONNECT
3041 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3042 #else
3043 FALSE,
3044 #endif
3045 string_from_gstring(ss));
3046
3047 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3048 handshake arrived. If so we must have managed a TFO. */
3049
3050 #ifdef TCP_FASTOPEN
3051 tfo_in_check();
3052 #endif
3053
3054 return TRUE;
3055 }
3056
3057
3058
3059
3060
3061 /*************************************************
3062 * Handle SMTP syntax and protocol errors *
3063 *************************************************/
3064
3065 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3066 to do so. Then transmit the error response. The return value depends on the
3067 number of syntax and protocol errors in this SMTP session.
3068
3069 Arguments:
3070 type error type, given as a log flag bit
3071 code response code; <= 0 means don't send a response
3072 data data to reflect in the response (can be NULL)
3073 errmess the error message
3074
3075 Returns: -1 limit of syntax/protocol errors NOT exceeded
3076 +1 limit of syntax/protocol errors IS exceeded
3077
3078 These values fit in with the values of the "done" variable in the main
3079 processing loop in smtp_setup_msg(). */
3080
3081 static int
3082 synprot_error(int type, int code, uschar *data, uschar *errmess)
3083 {
3084 int yield = -1;
3085
3086 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3087 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3088 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3089
3090 if (++synprot_error_count > smtp_max_synprot_errors)
3091 {
3092 yield = 1;
3093 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3094 "syntax or protocol errors (last command was \"%s\")",
3095 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3096 }
3097
3098 if (code > 0)
3099 {
3100 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3101 data ? data : US"", data ? US": " : US"", errmess);
3102 if (yield == 1)
3103 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3104 }
3105
3106 return yield;
3107 }
3108
3109
3110
3111
3112 /*************************************************
3113 * Send SMTP response, possibly multiline *
3114 *************************************************/
3115
3116 /* There are, it seems, broken clients out there that cannot handle multiline
3117 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3118 output nothing for non-final calls, and only the first line for anything else.
3119
3120 Arguments:
3121 code SMTP code, may involve extended status codes
3122 codelen length of smtp code; if > 4 there's an ESC
3123 final FALSE if the last line isn't the final line
3124 msg message text, possibly containing newlines
3125
3126 Returns: nothing
3127 */
3128
3129 void
3130 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3131 {
3132 int esclen = 0;
3133 uschar *esc = US"";
3134
3135 if (!final && f.no_multiline_responses) return;
3136
3137 if (codelen > 4)
3138 {
3139 esc = code + 4;
3140 esclen = codelen - 4;
3141 }
3142
3143 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3144 have had the same. Note: this code is also present in smtp_printf(). It would
3145 be tidier to have it only in one place, but when it was added, it was easier to
3146 do it that way, so as not to have to mess with the code for the RCPT command,
3147 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3148
3149 if (fl.rcpt_in_progress)
3150 {
3151 if (rcpt_smtp_response == NULL)
3152 rcpt_smtp_response = string_copy(msg);
3153 else if (fl.rcpt_smtp_response_same &&
3154 Ustrcmp(rcpt_smtp_response, msg) != 0)
3155 fl.rcpt_smtp_response_same = FALSE;
3156 fl.rcpt_in_progress = FALSE;
3157 }
3158
3159 /* Now output the message, splitting it up into multiple lines if necessary.
3160 We only handle pipelining these responses as far as nonfinal/final groups,
3161 not the whole MAIL/RCPT/DATA response set. */
3162
3163 for (;;)
3164 {
3165 uschar *nl = Ustrchr(msg, '\n');
3166 if (nl == NULL)
3167 {
3168 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3169 return;
3170 }
3171 else if (nl[1] == 0 || f.no_multiline_responses)
3172 {
3173 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3174 (int)(nl - msg), msg);
3175 return;
3176 }
3177 else
3178 {
3179 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3180 msg = nl + 1;
3181 while (isspace(*msg)) msg++;
3182 }
3183 }
3184 }
3185
3186
3187
3188
3189 /*************************************************
3190 * Parse user SMTP message *
3191 *************************************************/
3192
3193 /* This function allows for user messages overriding the response code details
3194 by providing a suitable response code string at the start of the message
3195 user_msg. Check the message for starting with a response code and optionally an
3196 extended status code. If found, check that the first digit is valid, and if so,
3197 change the code pointer and length to use the replacement. An invalid code
3198 causes a panic log; in this case, if the log messages is the same as the user
3199 message, we must also adjust the value of the log message to show the code that
3200 is actually going to be used (the original one).
3201
3202 This function is global because it is called from receive.c as well as within
3203 this module.
3204
3205 Note that the code length returned includes the terminating whitespace
3206 character, which is always included in the regex match.
3207
3208 Arguments:
3209 code SMTP code, may involve extended status codes
3210 codelen length of smtp code; if > 4 there's an ESC
3211 msg message text
3212 log_msg optional log message, to be adjusted with the new SMTP code
3213 check_valid if true, verify the response code
3214
3215 Returns: nothing
3216 */
3217
3218 void
3219 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3220 BOOL check_valid)
3221 {
3222 int n;
3223 int ovector[3];
3224
3225 if (!msg || !*msg) return;
3226
3227 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3228 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3229
3230 if (check_valid && (*msg)[0] != (*code)[0])
3231 {
3232 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3233 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3234 if (log_msg != NULL && *log_msg == *msg)
3235 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3236 }
3237 else
3238 {
3239 *code = *msg;
3240 *codelen = ovector[1]; /* Includes final space */
3241 }
3242 *msg += ovector[1]; /* Chop the code off the message */
3243 return;
3244 }
3245
3246
3247
3248
3249 /*************************************************
3250 * Handle an ACL failure *
3251 *************************************************/
3252
3253 /* This function is called when acl_check() fails. As well as calls from within
3254 this module, it is called from receive.c for an ACL after DATA. It sorts out
3255 logging the incident, and sends the error response. A message containing
3256 newlines is turned into a multiline SMTP response, but for logging, only the
3257 first line is used.
3258
3259 There's a table of default permanent failure response codes to use in
3260 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3261 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3262 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3263 state, because there are broken clients that try VRFY before RCPT. A 5xx
3264 response should be given only when the address is positively known to be
3265 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3266 no explicit code, but if there is one we let it know best.
3267 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3268
3269 From Exim 4.63, it is possible to override the response code details by
3270 providing a suitable response code string at the start of the message provided
3271 in user_msg. The code's first digit is checked for validity.
3272
3273 Arguments:
3274 where where the ACL was called from
3275 rc the failure code
3276 user_msg a message that can be included in an SMTP response
3277 log_msg a message for logging
3278
3279 Returns: 0 in most cases
3280 2 if the failure code was FAIL_DROP, in which case the
3281 SMTP connection should be dropped (this value fits with the
3282 "done" variable in smtp_setup_msg() below)
3283 */
3284
3285 int
3286 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3287 {
3288 BOOL drop = rc == FAIL_DROP;
3289 int codelen = 3;
3290 uschar *smtp_code;
3291 uschar *lognl;
3292 uschar *sender_info = US"";
3293 uschar *what =
3294 #ifdef WITH_CONTENT_SCAN
3295 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3296 #endif
3297 where == ACL_WHERE_PREDATA ? US"DATA" :
3298 where == ACL_WHERE_DATA ? US"after DATA" :
3299 #ifndef DISABLE_PRDR
3300 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3301 #endif
3302 smtp_cmd_data ?
3303 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3304 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3305
3306 if (drop) rc = FAIL;
3307
3308 /* Set the default SMTP code, and allow a user message to change it. */
3309
3310 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3311 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3312 where != ACL_WHERE_VRFY);
3313
3314 /* We used to have sender_address here; however, there was a bug that was not
3315 updating sender_address after a rewrite during a verify. When this bug was
3316 fixed, sender_address at this point became the rewritten address. I'm not sure
3317 this is what should be logged, so I've changed to logging the unrewritten
3318 address to retain backward compatibility. */
3319
3320 #ifndef WITH_CONTENT_SCAN
3321 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3322 #else
3323 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3324 #endif
3325 {
3326 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3327 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3328 sender_host_authenticated ? US" A=" : US"",
3329 sender_host_authenticated ? sender_host_authenticated : US"",
3330 sender_host_authenticated && authenticated_id ? US":" : US"",
3331 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3332 );
3333 }
3334
3335 /* If there's been a sender verification failure with a specific message, and
3336 we have not sent a response about it yet, do so now, as a preliminary line for
3337 failures, but not defers. However, always log it for defer, and log it for fail
3338 unless the sender_verify_fail log selector has been turned off. */
3339
3340 if (sender_verified_failed &&
3341 !testflag(sender_verified_failed, af_sverify_told))
3342 {
3343 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3344 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3345
3346 setflag(sender_verified_failed, af_sverify_told);
3347
3348 if (rc != FAIL || LOGGING(sender_verify_fail))
3349 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3350 host_and_ident(TRUE),
3351 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3352 sender_verified_failed->address,
3353 (sender_verified_failed->message == NULL)? US"" :
3354 string_sprintf(": %s", sender_verified_failed->message));
3355
3356 if (rc == FAIL && sender_verified_failed->user_message)
3357 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3358 testflag(sender_verified_failed, af_verify_pmfail)?
3359 "Postmaster verification failed while checking <%s>\n%s\n"
3360 "Several RFCs state that you are required to have a postmaster\n"
3361 "mailbox for each mail domain. This host does not accept mail\n"
3362 "from domains whose servers reject the postmaster address."
3363 :
3364 testflag(sender_verified_failed, af_verify_nsfail)?
3365 "Callback setup failed while verifying <%s>\n%s\n"
3366 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3367 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3368 "RFC requirements, and stops you from receiving standard bounce\n"
3369 "messages. This host does not accept mail from domains whose servers\n"
3370 "refuse bounces."
3371 :
3372 "Verification failed for <%s>\n%s",
3373 sender_verified_failed->address,
3374 sender_verified_failed->user_message));
3375
3376 fl.rcpt_in_progress = save_rcpt_in_progress;
3377 }
3378
3379 /* Sort out text for logging */
3380
3381 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3382 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3383
3384 /* Send permanent failure response to the command, but the code used isn't
3385 always a 5xx one - see comments at the start of this function. If the original
3386 rc was FAIL_DROP we drop the connection and yield 2. */
3387
3388 if (rc == FAIL)
3389 smtp_respond(smtp_code, codelen, TRUE,
3390 user_msg ? user_msg : US"Administrative prohibition");
3391
3392 /* Send temporary failure response to the command. Don't give any details,
3393 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3394 verb, and for a header verify when smtp_return_error_details is set.
3395
3396 This conditional logic is all somewhat of a mess because of the odd
3397 interactions between temp_details and return_error_details. One day it should
3398 be re-implemented in a tidier fashion. */
3399
3400 else
3401 if (f.acl_temp_details && user_msg)
3402 {
3403 if ( smtp_return_error_details
3404 && sender_verified_failed
3405 && sender_verified_failed->message
3406 )
3407 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3408
3409 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3410 }
3411 else
3412 smtp_respond(smtp_code, codelen, TRUE,
3413 US"Temporary local problem - please try later");
3414
3415 /* Log the incident to the logs that are specified by log_reject_target
3416 (default main, reject). This can be empty to suppress logging of rejections. If
3417 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3418 is closing if required and return 2. */
3419
3420 if (log_reject_target != 0)
3421 {
3422 #ifdef SUPPORT_TLS
3423 gstring * g = s_tlslog(NULL);
3424 uschar * tls = string_from_gstring(g);
3425 if (!tls) tls = US"";
3426 #else
3427 uschar * tls = US"";
3428 #endif
3429 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3430 log_reject_target, "%s%s%s %s%srejected %s%s",
3431 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3432 host_and_ident(TRUE),
3433 tls,
3434 sender_info,
3435 rc == FAIL ? US"" : US"temporarily ",
3436 what, log_msg);
3437 }
3438
3439 if (!drop) return 0;
3440
3441 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3442 smtp_get_connection_info());
3443
3444 /* Run the not-quit ACL, but without any custom messages. This should not be a
3445 problem, because we get here only if some other ACL has issued "drop", and
3446 in that case, *its* custom messages will have been used above. */
3447
3448 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3449 return 2;
3450 }
3451
3452
3453
3454
3455 /*************************************************
3456 * Handle SMTP exit when QUIT is not given *
3457 *************************************************/
3458
3459 /* This function provides a logging/statistics hook for when an SMTP connection
3460 is dropped on the floor or the other end goes away. It's a global function
3461 because it's called from receive.c as well as this module. As well as running
3462 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3463 response, either with a custom message from the ACL, or using a default. There
3464 is one case, however, when no message is output - after "drop". In that case,
3465 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3466 passed to this function.
3467
3468 In case things go wrong while processing this function, causing an error that
3469 may re-enter this function, there is a recursion check.
3470
3471 Arguments:
3472 reason What $smtp_notquit_reason will be set to in the ACL;
3473 if NULL, the ACL is not run
3474 code The error code to return as part of the response
3475 defaultrespond The default message if there's no user_msg
3476
3477 Returns: Nothing
3478 */
3479
3480 void
3481 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3482 {
3483 int rc;
3484 uschar *user_msg = NULL;
3485 uschar *log_msg = NULL;
3486
3487 /* Check for recursive call */
3488
3489 if (fl.smtp_exit_function_called)
3490 {
3491 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3492 reason);
3493 return;
3494 }
3495 fl.smtp_exit_function_called = TRUE;
3496
3497 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3498
3499 if (acl_smtp_notquit && reason)
3500 {
3501 smtp_notquit_reason = reason;
3502 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3503 &log_msg)) == ERROR)
3504 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3505 log_msg);
3506 }
3507
3508 /* If the connection was dropped, we certainly are no longer talking TLS */