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