tidying
[exim.git] / src / src / smtp_in.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8 /* Functions for handling an incoming SMTP call. */
9
10
11 #include "exim.h"
12 #include <assert.h>
13
14
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
18
19 #ifdef USE_TCP_WRAPPERS
20
21 #if HAVE_IPV6
22 #define EXIM_HAVE_IPV6
23 #endif
24 #undef HAVE_IPV6
25 #include <tcpd.h>
26 #undef HAVE_IPV6
27 #ifdef EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
29 #endif
30
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
34 #endif
35
36
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
45 */
46
47 #define SMTP_CMD_BUFFER_SIZE 16384
48
49 /* Size of buffer for reading SMTP incoming packets */
50
51 #define IN_BUFFER_SIZE 8192
52
53 /* Structure for SMTP command list */
54
55 typedef struct {
56 const char *name;
57 int len;
58 short int cmd;
59 short int has_arg;
60 short int is_mail_cmd;
61 } smtp_cmd_list;
62
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
65 block some spam. */
66
67 enum {
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
70
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
76
77 /* This is a dummy to identify the non-sync commands when pipelining */
78
79 NON_SYNC_CMD_PIPELINING,
80
81 /* These commands need not be synchronized when pipelining */
82
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
84
85 /* This is a dummy to identify the non-sync commands when not pipelining */
86
87 NON_SYNC_CMD_NON_PIPELINING,
88
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
99
100 BDAT_CMD,
101
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
105
106 AUTH_CMD,
107
108 /* I'm not sure about these, but I don't think they matter. */
109
110 QUIT_CMD, HELP_CMD,
111
112 #ifdef SUPPORT_PROXY
113 PROXY_FAIL_IGNORE_CMD,
114 #endif
115
116 /* These are specials that don't correspond to actual commands */
117
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
120
121
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
124
125 #define HAD(n) \
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
128
129
130 /*************************************************
131 * Local static variables *
132 *************************************************/
133
134 static struct {
135 BOOL auth_advertised :1;
136 #ifdef SUPPORT_TLS
137 BOOL tls_advertised :1;
138 # ifdef EXPERIMENTAL_REQUIRETLS
139 BOOL requiretls_advertised :1;
140 # endif
141 #endif
142 BOOL dsn_advertised :1;
143 BOOL esmtp :1;
144 BOOL helo_required :1;
145 BOOL helo_verify :1;
146 BOOL helo_seen :1;
147 BOOL helo_accept_junk :1;
148 #ifdef EXPERIMENTAL_PIPE_CONNECT
149 BOOL pipe_connect_acceptable :1;
150 #endif
151 BOOL rcpt_smtp_response_same :1;
152 BOOL rcpt_in_progress :1;
153 BOOL smtp_exit_function_called :1;
154 #ifdef SUPPORT_I18N
155 BOOL smtputf8_advertised :1;
156 #endif
157 } fl = {
158 .helo_required = FALSE,
159 .helo_verify = FALSE,
160 .smtp_exit_function_called = FALSE,
161 };
162
163 static auth_instance *authenticated_by;
164 static int count_nonmail;
165 static int nonmail_command_count;
166 static int synprot_error_count;
167 static int unknown_command_count;
168 static int sync_cmd_limit;
169 static int smtp_write_error = 0;
170
171 static uschar *rcpt_smtp_response;
172 static uschar *smtp_data_buffer;
173 static uschar *smtp_cmd_data;
174
175 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
176 final fields of all except AUTH are forced TRUE at the start of a new message
177 setup, to allow one of each between messages that is not counted as a nonmail
178 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
179 allow a new EHLO after starting up TLS.
180
181 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
182 counted. However, the flag is changed when AUTH is received, so that multiple
183 failing AUTHs will eventually hit the limit. After a successful AUTH, another
184 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
185 forced TRUE, to allow for the re-authentication that can happen at that point.
186
187 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
188 count of non-mail commands and possibly provoke an error.
189
190 tls_auth is a pseudo-command, never expected in input. It is activated
191 on TLS startup and looks for a tls authenticator. */
192
193 static smtp_cmd_list cmd_list[] = {
194 /* name len cmd has_arg is_mail_cmd */
195
196 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
197 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
198 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
199 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
200 #ifdef SUPPORT_TLS
201 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
202 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
203 #endif
204
205 /* If you change anything above here, also fix the definitions below. */
206
207 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
208 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
209 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
210 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
211 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
212 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
213 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
214 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
215 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
216 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
217 };
218
219 static smtp_cmd_list *cmd_list_end =
220 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
221
222 #define CMD_LIST_RSET 0
223 #define CMD_LIST_HELO 1
224 #define CMD_LIST_EHLO 2
225 #define CMD_LIST_AUTH 3
226 #define CMD_LIST_STARTTLS 4
227 #define CMD_LIST_TLS_AUTH 5
228
229 /* This list of names is used for performing the smtp_no_mail logging action.
230 It must be kept in step with the SCH_xxx enumerations. */
231
232 static uschar *smtp_names[] =
233 {
234 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
235 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
236 US"STARTTLS", US"VRFY" };
237
238 static uschar *protocols_local[] = {
239 US"local-smtp", /* HELO */
240 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
241 US"local-esmtp", /* EHLO */
242 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
243 US"local-esmtpa", /* EHLO->AUTH */
244 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
245 };
246 static uschar *protocols[] = {
247 US"smtp", /* HELO */
248 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
249 US"esmtp", /* EHLO */
250 US"esmtps", /* EHLO->STARTTLS->EHLO */
251 US"esmtpa", /* EHLO->AUTH */
252 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
253 };
254
255 #define pnormal 0
256 #define pextend 2
257 #define pcrpted 1 /* added to pextend or pnormal */
258 #define pauthed 2 /* added to pextend */
259
260 /* Sanity check and validate optional args to MAIL FROM: envelope */
261 enum {
262 ENV_MAIL_OPT_NULL,
263 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
264 #ifndef DISABLE_PRDR
265 ENV_MAIL_OPT_PRDR,
266 #endif
267 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
268 #ifdef SUPPORT_I18N
269 ENV_MAIL_OPT_UTF8,
270 #endif
271 #ifdef EXPERIMENTAL_REQUIRETLS
272 ENV_MAIL_OPT_REQTLS,
273 #endif
274 };
275 typedef struct {
276 uschar * name; /* option requested during MAIL cmd */
277 int value; /* enum type */
278 BOOL need_value; /* TRUE requires value (name=value pair format)
279 FALSE is a singleton */
280 } env_mail_type_t;
281 static env_mail_type_t env_mail_type_list[] = {
282 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
283 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
284 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
285 #ifndef DISABLE_PRDR
286 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
287 #endif
288 { US"RET", ENV_MAIL_OPT_RET, TRUE },
289 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
290 #ifdef SUPPORT_I18N
291 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
292 #endif
293 #ifdef EXPERIMENTAL_REQUIRETLS
294 /* https://tools.ietf.org/html/draft-ietf-uta-smtp-require-tls-03 */
295 { US"REQUIRETLS",ENV_MAIL_OPT_REQTLS, FALSE },
296 #endif
297 /* keep this the last entry */
298 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
299 };
300
301 /* When reading SMTP from a remote host, we have to use our own versions of the
302 C input-reading functions, in order to be able to flush the SMTP output only
303 when about to read more data from the socket. This is the only way to get
304 optimal performance when the client is using pipelining. Flushing for every
305 command causes a separate packet and reply packet each time; saving all the
306 responses up (when pipelining) combines them into one packet and one response.
307
308 For simplicity, these functions are used for *all* SMTP input, not only when
309 receiving over a socket. However, after setting up a secure socket (SSL), input
310 is read via the OpenSSL library, and another set of functions is used instead
311 (see tls.c).
312
313 These functions are set in the receive_getc etc. variables and called with the
314 same interface as the C functions. However, since there can only ever be
315 one incoming SMTP call, we just use a single buffer and flags. There is no need
316 to implement a complicated private FILE-like structure.*/
317
318 static uschar *smtp_inbuffer;
319 static uschar *smtp_inptr;
320 static uschar *smtp_inend;
321 static int smtp_had_eof;
322 static int smtp_had_error;
323
324
325 /* forward declarations */
326 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
327 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
328 static void smtp_quit_handler(uschar **, uschar **);
329 static void smtp_rset_handler(void);
330
331 /*************************************************
332 * Recheck synchronization *
333 *************************************************/
334
335 /* Synchronization checks can never be perfect because a packet may be on its
336 way but not arrived when the check is done. Normally, the checks happen when
337 commands are read: Exim ensures that there is no more input in the input buffer.
338 In normal cases, the response to the command will be fast, and there is no
339 further check.
340
341 However, for some commands an ACL is run, and that can include delays. In those
342 cases, it is useful to do another check on the input just before sending the
343 response. This also applies at the start of a connection. This function does
344 that check by means of the select() function, as long as the facility is not
345 disabled or inappropriate. A failure of select() is ignored.
346
347 When there is unwanted input, we read it so that it appears in the log of the
348 error.
349
350 Arguments: none
351 Returns: TRUE if all is well; FALSE if there is input pending
352 */
353
354 static BOOL
355 wouldblock_reading(void)
356 {
357 int fd, rc;
358 fd_set fds;
359 struct timeval tzero;
360
361 #ifdef SUPPORT_TLS
362 if (tls_in.active.sock >= 0)
363 return !tls_could_read();
364 #endif
365
366 if (smtp_inptr < smtp_inend)
367 return FALSE;
368
369 fd = fileno(smtp_in);
370 FD_ZERO(&fds);
371 FD_SET(fd, &fds);
372 tzero.tv_sec = 0;
373 tzero.tv_usec = 0;
374 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
375
376 if (rc <= 0) return TRUE; /* Not ready to read */
377 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
378 if (rc < 0) return TRUE; /* End of file or error */
379
380 smtp_ungetc(rc);
381 return FALSE;
382 }
383
384 static BOOL
385 check_sync(void)
386 {
387 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
388 return TRUE;
389
390 return wouldblock_reading();
391 }
392
393
394 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
395 a reponse with the one following. */
396
397 static BOOL
398 pipeline_response(void)
399 {
400 if ( !smtp_enforce_sync || !sender_host_address
401 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
402 return FALSE;
403
404 if (wouldblock_reading()) return FALSE;
405 f.smtp_in_pipelining_used = TRUE;
406 return TRUE;
407 }
408
409
410 #ifdef EXPERIMENTAL_PIPE_CONNECT
411 static BOOL
412 pipeline_connect_sends(void)
413 {
414 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
415 return FALSE;
416
417 if (wouldblock_reading()) return FALSE;
418 f.smtp_in_early_pipe_used = TRUE;
419 return TRUE;
420 }
421 #endif
422
423 /*************************************************
424 * Log incomplete transactions *
425 *************************************************/
426
427 /* This function is called after a transaction has been aborted by RSET, QUIT,
428 connection drops or other errors. It logs the envelope information received
429 so far in order to preserve address verification attempts.
430
431 Argument: string to indicate what aborted the transaction
432 Returns: nothing
433 */
434
435 static void
436 incomplete_transaction_log(uschar *what)
437 {
438 if (sender_address == NULL || /* No transaction in progress */
439 !LOGGING(smtp_incomplete_transaction))
440 return;
441
442 /* Build list of recipients for logging */
443
444 if (recipients_count > 0)
445 {
446 int i;
447 raw_recipients = store_get(recipients_count * sizeof(uschar *));
448 for (i = 0; i < recipients_count; i++)
449 raw_recipients[i] = recipients_list[i].address;
450 raw_recipients_count = recipients_count;
451 }
452
453 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
454 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
455 }
456
457
458
459
460 void
461 smtp_command_timeout_exit(void)
462 {
463 log_write(L_lost_incoming_connection,
464 LOG_MAIN, "SMTP command timeout on%s connection from %s",
465 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
466 if (smtp_batched_input)
467 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
468 smtp_notquit_exit(US"command-timeout", US"421",
469 US"%s: SMTP command timeout - closing connection",
470 smtp_active_hostname);
471 exim_exit(EXIT_FAILURE, US"receiving");
472 }
473
474 void
475 smtp_command_sigterm_exit(void)
476 {
477 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
478 if (smtp_batched_input)
479 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
480 smtp_notquit_exit(US"signal-exit", US"421",
481 US"%s: Service not available - closing connection", smtp_active_hostname);
482 exim_exit(EXIT_FAILURE, US"receiving");
483 }
484
485 void
486 smtp_data_timeout_exit(void)
487 {
488 log_write(L_lost_incoming_connection,
489 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
490 sender_fullhost ? sender_fullhost : US"local process", sender_address);
491 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
492 /* Does not return */
493 }
494
495 void
496 smtp_data_sigint_exit(void)
497 {
498 log_write(0, LOG_MAIN, "%s closed after %s",
499 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
500 receive_bomb_out(US"signal-exit",
501 US"Service not available - SIGTERM or SIGINT received");
502 /* Does not return */
503 }
504
505
506
507 /* Refill the buffer, and notify DKIM verification code.
508 Return false for error or EOF.
509 */
510
511 static BOOL
512 smtp_refill(unsigned lim)
513 {
514 int rc, save_errno;
515 if (!smtp_out) return FALSE;
516 fflush(smtp_out);
517 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
518
519 /* Limit amount read, so non-message data is not fed to DKIM.
520 Take care to not touch the safety NUL at the end of the buffer. */
521
522 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
523 save_errno = errno;
524 if (smtp_receive_timeout > 0) ALARM_CLR(0);
525 if (rc <= 0)
526 {
527 /* Must put the error text in fixed store, because this might be during
528 header reading, where it releases unused store above the header. */
529 if (rc < 0)
530 {
531 if (had_command_timeout) /* set by signal handler */
532 smtp_command_timeout_exit(); /* does not return */
533 if (had_command_sigterm)
534 smtp_command_sigterm_exit();
535 if (had_data_timeout)
536 smtp_data_timeout_exit();
537 if (had_data_sigint)
538 smtp_data_sigint_exit();
539
540 smtp_had_error = save_errno;
541 smtp_read_error = string_copy_malloc(
542 string_sprintf(" (error: %s)", strerror(save_errno)));
543 }
544 else
545 smtp_had_eof = 1;
546 return FALSE;
547 }
548 #ifndef DISABLE_DKIM
549 dkim_exim_verify_feed(smtp_inbuffer, rc);
550 #endif
551 smtp_inend = smtp_inbuffer + rc;
552 smtp_inptr = smtp_inbuffer;
553 return TRUE;
554 }
555
556 /*************************************************
557 * SMTP version of getc() *
558 *************************************************/
559
560 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
561 it flushes the output, and refills the buffer, with a timeout. The signal
562 handler is set appropriately by the calling function. This function is not used
563 after a connection has negotiated itself into an TLS/SSL state.
564
565 Arguments: lim Maximum amount to read/buffer
566 Returns: the next character or EOF
567 */
568
569 int
570 smtp_getc(unsigned lim)
571 {
572 if (smtp_inptr >= smtp_inend)
573 if (!smtp_refill(lim))
574 return EOF;
575 return *smtp_inptr++;
576 }
577
578 uschar *
579 smtp_getbuf(unsigned * len)
580 {
581 unsigned size;
582 uschar * buf;
583
584 if (smtp_inptr >= smtp_inend)
585 if (!smtp_refill(*len))
586 { *len = 0; return NULL; }
587
588 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
589 buf = smtp_inptr;
590 smtp_inptr += size;
591 *len = size;
592 return buf;
593 }
594
595 void
596 smtp_get_cache(void)
597 {
598 #ifndef DISABLE_DKIM
599 int n = smtp_inend - smtp_inptr;
600 if (n > 0)
601 dkim_exim_verify_feed(smtp_inptr, n);
602 #endif
603 }
604
605
606 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
607 previous BDAT chunk and getting new ones when we run out. Uses the
608 underlying smtp_getc or tls_getc both for that and for getting the
609 (buffered) data byte. EOD signals (an expected) no further data.
610 ERR signals a protocol error, and EOF a closed input stream.
611
612 Called from read_bdat_smtp() in receive.c for the message body, but also
613 by the headers read loop in receive_msg(); manipulates chunking_state
614 to handle the BDAT command/response.
615 Placed here due to the correlation with the above smtp_getc(), which it wraps,
616 and also by the need to do smtp command/response handling.
617
618 Arguments: lim (ignored)
619 Returns: the next character or ERR, EOD or EOF
620 */
621
622 int
623 bdat_getc(unsigned lim)
624 {
625 uschar * user_msg = NULL;
626 uschar * log_msg;
627
628 for(;;)
629 {
630 #ifndef DISABLE_DKIM
631 unsigned dkim_save;
632 #endif
633
634 if (chunking_data_left > 0)
635 return lwr_receive_getc(chunking_data_left--);
636
637 receive_getc = lwr_receive_getc;
638 receive_getbuf = lwr_receive_getbuf;
639 receive_ungetc = lwr_receive_ungetc;
640 #ifndef DISABLE_DKIM
641 dkim_save = dkim_collect_input;
642 dkim_collect_input = 0;
643 #endif
644
645 /* Unless PIPELINING was offered, there should be no next command
646 until after we ack that chunk */
647
648 if (!f.smtp_in_pipelining_advertised && !check_sync())
649 {
650 unsigned n = smtp_inend - smtp_inptr;
651 if (n > 32) n = 32;
652
653 incomplete_transaction_log(US"sync failure");
654 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
655 "(next input sent too soon: pipelining was not advertised): "
656 "rejected \"%s\" %s next input=\"%s\"%s",
657 smtp_cmd_buffer, host_and_ident(TRUE),
658 string_printing(string_copyn(smtp_inptr, n)),
659 smtp_inend - smtp_inptr > n ? "..." : "");
660 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
661 US"SMTP synchronization error");
662 goto repeat_until_rset;
663 }
664
665 /* If not the last, ack the received chunk. The last response is delayed
666 until after the data ACL decides on it */
667
668 if (chunking_state == CHUNKING_LAST)
669 {
670 #ifndef DISABLE_DKIM
671 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
672 #endif
673 return EOD;
674 }
675
676 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
677 chunking_state = CHUNKING_OFFERED;
678 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
679
680 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
681 QUIT, RSET or NOOP but handling them seems obvious */
682
683 next_cmd:
684 switch(smtp_read_command(TRUE, 1))
685 {
686 default:
687 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
688 US"only BDAT permissible after non-LAST BDAT");
689
690 repeat_until_rset:
691 switch(smtp_read_command(TRUE, 1))
692 {
693 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
694 case EOF_CMD: return EOF;
695 case RSET_CMD: smtp_rset_handler(); return ERR;
696 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
697 US"only RSET accepted now") > 0)
698 return EOF;
699 goto repeat_until_rset;
700 }
701
702 case QUIT_CMD:
703 smtp_quit_handler(&user_msg, &log_msg);
704 /*FALLTHROUGH*/
705 case EOF_CMD:
706 return EOF;
707
708 case RSET_CMD:
709 smtp_rset_handler();
710 return ERR;
711
712 case NOOP_CMD:
713 HAD(SCH_NOOP);
714 smtp_printf("250 OK\r\n", FALSE);
715 goto next_cmd;
716
717 case BDAT_CMD:
718 {
719 int n;
720
721 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
722 {
723 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
724 US"missing size for BDAT command");
725 return ERR;
726 }
727 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
728 ? CHUNKING_LAST : CHUNKING_ACTIVE;
729 chunking_data_left = chunking_datasize;
730 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
731 (int)chunking_state, chunking_data_left);
732
733 if (chunking_datasize == 0)
734 if (chunking_state == CHUNKING_LAST)
735 return EOD;
736 else
737 {
738 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
739 US"zero size for BDAT command");
740 goto repeat_until_rset;
741 }
742
743 receive_getc = bdat_getc;
744 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
745 receive_ungetc = bdat_ungetc;
746 #ifndef DISABLE_DKIM
747 dkim_collect_input = dkim_save;
748 #endif
749 break; /* to top of main loop */
750 }
751 }
752 }
753 }
754
755 uschar *
756 bdat_getbuf(unsigned * len)
757 {
758 uschar * buf;
759
760 if (chunking_data_left <= 0)
761 { *len = 0; return NULL; }
762
763 if (*len > chunking_data_left) *len = chunking_data_left;
764 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
765 chunking_data_left -= *len;
766 return buf;
767 }
768
769 void
770 bdat_flush_data(void)
771 {
772 while (chunking_data_left)
773 {
774 unsigned n = chunking_data_left;
775 if (!bdat_getbuf(&n)) break;
776 }
777
778 receive_getc = lwr_receive_getc;
779 receive_getbuf = lwr_receive_getbuf;
780 receive_ungetc = lwr_receive_ungetc;
781
782 if (chunking_state != CHUNKING_LAST)
783 {
784 chunking_state = CHUNKING_OFFERED;
785 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
786 }
787 }
788
789
790
791
792 /*************************************************
793 * SMTP version of ungetc() *
794 *************************************************/
795
796 /* Puts a character back in the input buffer. Only ever
797 called once.
798
799 Arguments:
800 ch the character
801
802 Returns: the character
803 */
804
805 int
806 smtp_ungetc(int ch)
807 {
808 *--smtp_inptr = ch;
809 return ch;
810 }
811
812
813 int
814 bdat_ungetc(int ch)
815 {
816 chunking_data_left++;
817 return lwr_receive_ungetc(ch);
818 }
819
820
821
822 /*************************************************
823 * SMTP version of feof() *
824 *************************************************/
825
826 /* Tests for a previous EOF
827
828 Arguments: none
829 Returns: non-zero if the eof flag is set
830 */
831
832 int
833 smtp_feof(void)
834 {
835 return smtp_had_eof;
836 }
837
838
839
840
841 /*************************************************
842 * SMTP version of ferror() *
843 *************************************************/
844
845 /* Tests for a previous read error, and returns with errno
846 restored to what it was when the error was detected.
847
848 Arguments: none
849 Returns: non-zero if the error flag is set
850 */
851
852 int
853 smtp_ferror(void)
854 {
855 errno = smtp_had_error;
856 return smtp_had_error;
857 }
858
859
860
861 /*************************************************
862 * Test for characters in the SMTP buffer *
863 *************************************************/
864
865 /* Used at the end of a message
866
867 Arguments: none
868 Returns: TRUE/FALSE
869 */
870
871 BOOL
872 smtp_buffered(void)
873 {
874 return smtp_inptr < smtp_inend;
875 }
876
877
878
879 /*************************************************
880 * Write formatted string to SMTP channel *
881 *************************************************/
882
883 /* This is a separate function so that we don't have to repeat everything for
884 TLS support or debugging. It is global so that the daemon and the
885 authentication functions can use it. It does not return any error indication,
886 because major problems such as dropped connections won't show up till an output
887 flush for non-TLS connections. The smtp_fflush() function is available for
888 checking that: for convenience, TLS output errors are remembered here so that
889 they are also picked up later by smtp_fflush().
890
891 Arguments:
892 format format string
893 more further data expected
894 ... optional arguments
895
896 Returns: nothing
897 */
898
899 void
900 smtp_printf(const char *format, BOOL more, ...)
901 {
902 va_list ap;
903
904 va_start(ap, more);
905 smtp_vprintf(format, more, ap);
906 va_end(ap);
907 }
908
909 /* This is split off so that verify.c:respond_printf() can, in effect, call
910 smtp_printf(), bearing in mind that in C a vararg function can't directly
911 call another vararg function, only a function which accepts a va_list. */
912
913 void
914 smtp_vprintf(const char *format, BOOL more, va_list ap)
915 {
916 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
917 BOOL yield;
918
919 yield = !! string_vformat(&gs, FALSE, format, ap);
920 string_from_gstring(&gs);
921
922 DEBUG(D_receive)
923 {
924 void *reset_point = store_get(0);
925 uschar *msg_copy, *cr, *end;
926 msg_copy = string_copy(gs.s);
927 end = msg_copy + gs.ptr;
928 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
929 memmove(cr, cr + 1, (end--) - cr);
930 debug_printf("SMTP>> %s", msg_copy);
931 store_reset(reset_point);
932 }
933
934 if (!yield)
935 {
936 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
937 smtp_closedown(US"Unexpected error");
938 exim_exit(EXIT_FAILURE, NULL);
939 }
940
941 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
942 have had the same. Note: this code is also present in smtp_respond(). It would
943 be tidier to have it only in one place, but when it was added, it was easier to
944 do it that way, so as not to have to mess with the code for the RCPT command,
945 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
946
947 if (fl.rcpt_in_progress)
948 {
949 if (rcpt_smtp_response == NULL)
950 rcpt_smtp_response = string_copy(big_buffer);
951 else if (fl.rcpt_smtp_response_same &&
952 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
953 fl.rcpt_smtp_response_same = FALSE;
954 fl.rcpt_in_progress = FALSE;
955 }
956
957 /* Now write the string */
958
959 #ifdef SUPPORT_TLS
960 if (tls_in.active.sock >= 0)
961 {
962 if (tls_write(NULL, gs.s, gs.ptr, more) < 0)
963 smtp_write_error = -1;
964 }
965 else
966 #endif
967
968 if (fprintf(smtp_out, "%s", gs.s) < 0) smtp_write_error = -1;
969 }
970
971
972
973 /*************************************************
974 * Flush SMTP out and check for error *
975 *************************************************/
976
977 /* This function isn't currently used within Exim (it detects errors when it
978 tries to read the next SMTP input), but is available for use in local_scan().
979 For non-TLS connections, it flushes the output and checks for errors. For
980 TLS-connections, it checks for a previously-detected TLS write error.
981
982 Arguments: none
983 Returns: 0 for no error; -1 after an error
984 */
985
986 int
987 smtp_fflush(void)
988 {
989 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
990 return smtp_write_error;
991 }
992
993
994
995 /*************************************************
996 * SMTP command read timeout *
997 *************************************************/
998
999 /* Signal handler for timing out incoming SMTP commands. This attempts to
1000 finish off tidily.
1001
1002 Argument: signal number (SIGALRM)
1003 Returns: nothing
1004 */
1005
1006 static void
1007 command_timeout_handler(int sig)
1008 {
1009 had_command_timeout = sig;
1010 }
1011
1012
1013
1014 /*************************************************
1015 * SIGTERM received *
1016 *************************************************/
1017
1018 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1019
1020 Argument: signal number (SIGTERM)
1021 Returns: nothing
1022 */
1023
1024 static void
1025 command_sigterm_handler(int sig)
1026 {
1027 had_command_sigterm = sig;
1028 }
1029
1030
1031
1032
1033 #ifdef SUPPORT_PROXY
1034 /*************************************************
1035 * Restore socket timeout to previous value *
1036 *************************************************/
1037 /* If the previous value was successfully retrieved, restore
1038 it before returning control to the non-proxy routines
1039
1040 Arguments: fd - File descriptor for input
1041 get_ok - Successfully retrieved previous values
1042 tvtmp - Time struct with previous values
1043 vslen - Length of time struct
1044 Returns: none
1045 */
1046 static void
1047 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1048 {
1049 if (get_ok == 0)
1050 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1051 }
1052
1053 /*************************************************
1054 * Check if host is required proxy host *
1055 *************************************************/
1056 /* The function determines if inbound host will be a regular smtp host
1057 or if it is configured that it must use Proxy Protocol. A local
1058 connection cannot.
1059
1060 Arguments: none
1061 Returns: bool
1062 */
1063
1064 static BOOL
1065 check_proxy_protocol_host()
1066 {
1067 int rc;
1068
1069 if ( sender_host_address
1070 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1071 sender_host_address, NULL)) == OK)
1072 {
1073 DEBUG(D_receive)
1074 debug_printf("Detected proxy protocol configured host\n");
1075 proxy_session = TRUE;
1076 }
1077 return proxy_session;
1078 }
1079
1080
1081 /*************************************************
1082 * Read data until newline or end of buffer *
1083 *************************************************/
1084 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1085 read an entire buffer and assume there will be nothing past a proxy protocol
1086 header. Our approach normally is to use stdio, but again that relies upon
1087 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1088 reading _nothing_ before client TLS handshake. So we don't want to use the
1089 usual buffering reads which may read enough to block TLS starting.
1090
1091 So unfortunately we're down to "read one byte at a time, with a syscall each,
1092 and expect a little overhead", for all proxy-opened connections which are v1,
1093 just to handle the TLS-on-connect case. Since SSL functions wrap the
1094 underlying fd, we can't assume that we can feed them any already-read content.
1095
1096 We need to know where to read to, the max capacity, and we'll read until we
1097 get a CR and one more character. Let the caller scream if it's CR+!LF.
1098
1099 Return the amount read.
1100 */
1101
1102 static int
1103 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1104 {
1105 uschar *to = base + already;
1106 uschar *cr;
1107 int have = 0;
1108 int ret;
1109 int last = 0;
1110
1111 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1112 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1113
1114 cr = memchr(base, '\r', already);
1115 if (cr != NULL)
1116 {
1117 if ((cr - base) < already - 1)
1118 {
1119 /* \r and presumed \n already within what we have; probably not
1120 actually proxy protocol, but abort cleanly. */
1121 return 0;
1122 }
1123 /* \r is last character read, just need one more. */
1124 last = 1;
1125 }
1126
1127 while (capacity > 0)
1128 {
1129 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1130 if (ret == -1)
1131 return -1;
1132 have++;
1133 if (last)
1134 return have;
1135 if (*to == '\r')
1136 last = 1;
1137 capacity--;
1138 to++;
1139 }
1140
1141 /* reached end without having room for a final newline, abort */
1142 errno = EOVERFLOW;
1143 return -1;
1144 }
1145
1146 /*************************************************
1147 * Setup host for proxy protocol *
1148 *************************************************/
1149 /* The function configures the connection based on a header from the
1150 inbound host to use Proxy Protocol. The specification is very exact
1151 so exit with an error if do not find the exact required pieces. This
1152 includes an incorrect number of spaces separating args.
1153
1154 Arguments: none
1155 Returns: Boolean success
1156 */
1157
1158 static void
1159 setup_proxy_protocol_host()
1160 {
1161 union {
1162 struct {
1163 uschar line[108];
1164 } v1;
1165 struct {
1166 uschar sig[12];
1167 uint8_t ver_cmd;
1168 uint8_t fam;
1169 uint16_t len;
1170 union {
1171 struct { /* TCP/UDP over IPv4, len = 12 */
1172 uint32_t src_addr;
1173 uint32_t dst_addr;
1174 uint16_t src_port;
1175 uint16_t dst_port;
1176 } ip4;
1177 struct { /* TCP/UDP over IPv6, len = 36 */
1178 uint8_t src_addr[16];
1179 uint8_t dst_addr[16];
1180 uint16_t src_port;
1181 uint16_t dst_port;
1182 } ip6;
1183 struct { /* AF_UNIX sockets, len = 216 */
1184 uschar src_addr[108];
1185 uschar dst_addr[108];
1186 } unx;
1187 } addr;
1188 } v2;
1189 } hdr;
1190
1191 /* Temp variables used in PPv2 address:port parsing */
1192 uint16_t tmpport;
1193 char tmpip[INET_ADDRSTRLEN];
1194 struct sockaddr_in tmpaddr;
1195 char tmpip6[INET6_ADDRSTRLEN];
1196 struct sockaddr_in6 tmpaddr6;
1197
1198 /* We can't read "all data until end" because while SMTP is
1199 server-speaks-first, the TLS handshake is client-speaks-first, so for
1200 TLS-on-connect ports the proxy protocol header will usually be immediately
1201 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1202 reinject data for reading by those. So instead we first read "enough to be
1203 safely read within the header, and figure out how much more to read".
1204 For v1 we will later read to the end-of-line, for v2 we will read based upon
1205 the stated length.
1206
1207 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1208 data is needed total. For v1, where the line looks like:
1209 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1210
1211 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1212 We seem to support that. So, if we read 14 octets then we can tell if we're
1213 v2 or v1. If we're v1, we can continue reading as normal.
1214
1215 If we're v2, we can't slurp up the entire header. We need the length in the
1216 15th & 16th octets, then to read everything after that.
1217
1218 So to safely handle v1 and v2, with client-sent-first supported correctly,
1219 we have to do a minimum of 3 read calls, not 1. Eww.
1220 */
1221
1222 #define PROXY_INITIAL_READ 14
1223 #define PROXY_V2_HEADER_SIZE 16
1224 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1225 # error Code bug in sizes of data to read for proxy usage
1226 #endif
1227
1228 int get_ok = 0;
1229 int size, ret;
1230 int fd = fileno(smtp_in);
1231 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1232 uschar * iptype; /* To display debug info */
1233 struct timeval tv;
1234 struct timeval tvtmp;
1235 socklen_t vslen = sizeof(struct timeval);
1236 BOOL yield = FALSE;
1237
1238 /* Save current socket timeout values */
1239 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1240
1241 /* Proxy Protocol host must send header within a short time
1242 (default 3 seconds) or it's considered invalid */
1243 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1244 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1245 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1246 goto bad;
1247
1248 do
1249 {
1250 /* The inbound host was declared to be a Proxy Protocol host, so
1251 don't do a PEEK into the data, actually slurp up enough to be
1252 "safe". Can't take it all because TLS-on-connect clients follow
1253 immediately with TLS handshake. */
1254 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1255 }
1256 while (ret == -1 && errno == EINTR);
1257
1258 if (ret == -1)
1259 goto proxyfail;
1260
1261 /* For v2, handle reading the length, and then the rest. */
1262 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1263 {
1264 int retmore;
1265 uint8_t ver;
1266
1267 /* First get the length fields. */
1268 do
1269 {
1270 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1271 } while (retmore == -1 && errno == EINTR);
1272 if (retmore == -1)
1273 goto proxyfail;
1274 ret += retmore;
1275
1276 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1277
1278 /* May 2014: haproxy combined the version and command into one byte to
1279 allow two full bytes for the length field in order to proxy SSL
1280 connections. SSL Proxy is not supported in this version of Exim, but
1281 must still separate values here. */
1282
1283 if (ver != 0x02)
1284 {
1285 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1286 goto proxyfail;
1287 }
1288
1289 /* The v2 header will always be 16 bytes per the spec. */
1290 size = 16 + ntohs(hdr.v2.len);
1291 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1292 size, (int)sizeof(hdr));
1293
1294 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1295 amount that we need. Double-check that the size is not unreasonable, then
1296 get the rest. */
1297 if (size > sizeof(hdr))
1298 {
1299 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1300 goto proxyfail;
1301 }
1302
1303 do
1304 {
1305 do
1306 {
1307 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1308 } while (retmore == -1 && errno == EINTR);
1309 if (retmore == -1)
1310 goto proxyfail;
1311 ret += retmore;
1312 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1313 } while (ret < size);
1314
1315 } /* end scope for getting rest of data for v2 */
1316
1317 /* At this point: if PROXYv2, we've read the exact size required for all data;
1318 if PROXYv1 then we've read "less than required for any valid line" and should
1319 read the rest". */
1320
1321 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1322 {
1323 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1324
1325 switch (cmd)
1326 {
1327 case 0x01: /* PROXY command */
1328 switch (hdr.v2.fam)
1329 {
1330 case 0x11: /* TCPv4 address type */
1331 iptype = US"IPv4";
1332 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1333 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1334 if (!string_is_ip_address(US tmpip, NULL))
1335 {
1336 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1337 goto proxyfail;
1338 }
1339 proxy_local_address = sender_host_address;
1340 sender_host_address = string_copy(US tmpip);
1341 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1342 proxy_local_port = sender_host_port;
1343 sender_host_port = tmpport;
1344 /* Save dest ip/port */
1345 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1346 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1347 if (!string_is_ip_address(US tmpip, NULL))
1348 {
1349 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1350 goto proxyfail;
1351 }
1352 proxy_external_address = string_copy(US tmpip);
1353 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1354 proxy_external_port = tmpport;
1355 goto done;
1356 case 0x21: /* TCPv6 address type */
1357 iptype = US"IPv6";
1358 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1359 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1360 if (!string_is_ip_address(US tmpip6, NULL))
1361 {
1362 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1363 goto proxyfail;
1364 }
1365 proxy_local_address = sender_host_address;
1366 sender_host_address = string_copy(US tmpip6);
1367 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1368 proxy_local_port = sender_host_port;
1369 sender_host_port = tmpport;
1370 /* Save dest ip/port */
1371 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1372 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1373 if (!string_is_ip_address(US tmpip6, NULL))
1374 {
1375 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1376 goto proxyfail;
1377 }
1378 proxy_external_address = string_copy(US tmpip6);
1379 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1380 proxy_external_port = tmpport;
1381 goto done;
1382 default:
1383 DEBUG(D_receive)
1384 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1385 hdr.v2.fam);
1386 goto proxyfail;
1387 }
1388 /* Unsupported protocol, keep local connection address */
1389 break;
1390 case 0x00: /* LOCAL command */
1391 /* Keep local connection address for LOCAL */
1392 iptype = US"local";
1393 break;
1394 default:
1395 DEBUG(D_receive)
1396 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1397 goto proxyfail;
1398 }
1399 }
1400 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1401 {
1402 uschar *p;
1403 uschar *end;
1404 uschar *sp; /* Utility variables follow */
1405 int tmp_port;
1406 int r2;
1407 char *endc;
1408
1409 /* get the rest of the line */
1410 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1411 if (r2 == -1)
1412 goto proxyfail;
1413 ret += r2;
1414
1415 p = string_copy(hdr.v1.line);
1416 end = memchr(p, '\r', ret - 1);
1417
1418 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1419 {
1420 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1421 goto proxyfail;
1422 }
1423 *end = '\0'; /* Terminate the string */
1424 size = end + 2 - p; /* Skip header + CRLF */
1425 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1426 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1427 /* Step through the string looking for the required fields. Ensure
1428 strict adherence to required formatting, exit for any error. */
1429 p += 5;
1430 if (!isspace(*(p++)))
1431 {
1432 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1433 goto proxyfail;
1434 }
1435 if (!Ustrncmp(p, CCS"TCP4", 4))
1436 iptype = US"IPv4";
1437 else if (!Ustrncmp(p,CCS"TCP6", 4))
1438 iptype = US"IPv6";
1439 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1440 {
1441 iptype = US"Unknown";
1442 goto done;
1443 }
1444 else
1445 {
1446 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1447 goto proxyfail;
1448 }
1449
1450 p += Ustrlen(iptype);
1451 if (!isspace(*(p++)))
1452 {
1453 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1454 goto proxyfail;
1455 }
1456 /* Find the end of the arg */
1457 if ((sp = Ustrchr(p, ' ')) == NULL)
1458 {
1459 DEBUG(D_receive)
1460 debug_printf("Did not find proxied src %s\n", iptype);
1461 goto proxyfail;
1462 }
1463 *sp = '\0';
1464 if(!string_is_ip_address(p, NULL))
1465 {
1466 DEBUG(D_receive)
1467 debug_printf("Proxied src arg is not an %s address\n", iptype);
1468 goto proxyfail;
1469 }
1470 proxy_local_address = sender_host_address;
1471 sender_host_address = p;
1472 p = sp + 1;
1473 if ((sp = Ustrchr(p, ' ')) == NULL)
1474 {
1475 DEBUG(D_receive)
1476 debug_printf("Did not find proxy dest %s\n", iptype);
1477 goto proxyfail;
1478 }
1479 *sp = '\0';
1480 if(!string_is_ip_address(p, NULL))
1481 {
1482 DEBUG(D_receive)
1483 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1484 goto proxyfail;
1485 }
1486 proxy_external_address = p;
1487 p = sp + 1;
1488 if ((sp = Ustrchr(p, ' ')) == NULL)
1489 {
1490 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1491 goto proxyfail;
1492 }
1493 *sp = '\0';
1494 tmp_port = strtol(CCS p, &endc, 10);
1495 if (*endc || tmp_port == 0)
1496 {
1497 DEBUG(D_receive)
1498 debug_printf("Proxied src port '%s' not an integer\n", p);
1499 goto proxyfail;
1500 }
1501 proxy_local_port = sender_host_port;
1502 sender_host_port = tmp_port;
1503 p = sp + 1;
1504 if ((sp = Ustrchr(p, '\0')) == NULL)
1505 {
1506 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1507 goto proxyfail;
1508 }
1509 tmp_port = strtol(CCS p, &endc, 10);
1510 if (*endc || tmp_port == 0)
1511 {
1512 DEBUG(D_receive)
1513 debug_printf("Proxy dest port '%s' not an integer\n", p);
1514 goto proxyfail;
1515 }
1516 proxy_external_port = tmp_port;
1517 /* Already checked for /r /n above. Good V1 header received. */
1518 }
1519 else
1520 {
1521 /* Wrong protocol */
1522 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1523 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1524 goto proxyfail;
1525 }
1526
1527 done:
1528 DEBUG(D_receive)
1529 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1530 yield = proxy_session;
1531
1532 /* Don't flush any potential buffer contents. Any input on proxyfail
1533 should cause a synchronization failure */
1534
1535 proxyfail:
1536 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1537
1538 bad:
1539 if (yield)
1540 {
1541 sender_host_name = NULL;
1542 (void) host_name_lookup();
1543 host_build_sender_fullhost();
1544 }
1545 else
1546 {
1547 f.proxy_session_failed = TRUE;
1548 DEBUG(D_receive)
1549 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1550 }
1551
1552 return;
1553 }
1554 #endif
1555
1556 /*************************************************
1557 * Read one command line *
1558 *************************************************/
1559
1560 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1561 There are sites that don't do this, and in any case internal SMTP probably
1562 should check only for LF. Consequently, we check here for LF only. The line
1563 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1564 an unknown command. The command is read into the global smtp_cmd_buffer so that
1565 it is available via $smtp_command.
1566
1567 The character reading routine sets up a timeout for each block actually read
1568 from the input (which may contain more than one command). We set up a special
1569 signal handler that closes down the session on a timeout. Control does not
1570 return when it runs.
1571
1572 Arguments:
1573 check_sync if TRUE, check synchronization rules if global option is TRUE
1574 buffer_lim maximum to buffer in lower layer
1575
1576 Returns: a code identifying the command (enumerated above)
1577 */
1578
1579 static int
1580 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1581 {
1582 int c;
1583 int ptr = 0;
1584 smtp_cmd_list *p;
1585 BOOL hadnull = FALSE;
1586
1587 had_command_timeout = 0;
1588 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1589
1590 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1591 {
1592 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1593 {
1594 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1595 return OTHER_CMD;
1596 }
1597 if (c == 0)
1598 {
1599 hadnull = TRUE;
1600 c = '?';
1601 }
1602 smtp_cmd_buffer[ptr++] = c;
1603 }
1604
1605 receive_linecount++; /* For BSMTP errors */
1606 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1607
1608 /* If hit end of file, return pseudo EOF command. Whether we have a
1609 part-line already read doesn't matter, since this is an error state. */
1610
1611 if (c == EOF) return EOF_CMD;
1612
1613 /* Remove any CR and white space at the end of the line, and terminate the
1614 string. */
1615
1616 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1617 smtp_cmd_buffer[ptr] = 0;
1618
1619 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1620
1621 /* NULLs are not allowed in SMTP commands */
1622
1623 if (hadnull) return BADCHAR_CMD;
1624
1625 /* Scan command list and return identity, having set the data pointer
1626 to the start of the actual data characters. Check for SMTP synchronization
1627 if required. */
1628
1629 for (p = cmd_list; p < cmd_list_end; p++)
1630 {
1631 #ifdef SUPPORT_PROXY
1632 /* Only allow QUIT command if Proxy Protocol parsing failed */
1633 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1634 continue;
1635 #endif
1636 if ( p->len
1637 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1638 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1639 || smtp_cmd_buffer[p->len] == 0
1640 || smtp_cmd_buffer[p->len] == ' '
1641 ) )
1642 {
1643 if (smtp_inptr < smtp_inend && /* Outstanding input */
1644 p->cmd < sync_cmd_limit && /* Command should sync */
1645 check_sync && /* Local flag set */
1646 smtp_enforce_sync && /* Global flag set */
1647 sender_host_address != NULL && /* Not local input */
1648 !f.sender_host_notsocket) /* Really is a socket */
1649 return BADSYN_CMD;
1650
1651 /* The variables $smtp_command and $smtp_command_argument point into the
1652 unmodified input buffer. A copy of the latter is taken for actual
1653 processing, so that it can be chopped up into separate parts if necessary,
1654 for example, when processing a MAIL command options such as SIZE that can
1655 follow the sender address. */
1656
1657 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1658 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1659 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1660 smtp_cmd_data = smtp_data_buffer;
1661
1662 /* Count non-mail commands from those hosts that are controlled in this
1663 way. The default is all hosts. We don't waste effort checking the list
1664 until we get a non-mail command, but then cache the result to save checking
1665 again. If there's a DEFER while checking the host, assume it's in the list.
1666
1667 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1668 start of each incoming message by fiddling with the value in the table. */
1669
1670 if (!p->is_mail_cmd)
1671 {
1672 if (count_nonmail == TRUE_UNSET) count_nonmail =
1673 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1674 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1675 return TOO_MANY_NONMAIL_CMD;
1676 }
1677
1678 /* If there is data for a command that does not expect it, generate the
1679 error here. */
1680
1681 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1682 }
1683 }
1684
1685 #ifdef SUPPORT_PROXY
1686 /* Only allow QUIT command if Proxy Protocol parsing failed */
1687 if (proxy_session && f.proxy_session_failed)
1688 return PROXY_FAIL_IGNORE_CMD;
1689 #endif
1690
1691 /* Enforce synchronization for unknown commands */
1692
1693 if ( smtp_inptr < smtp_inend /* Outstanding input */
1694 && check_sync /* Local flag set */
1695 && smtp_enforce_sync /* Global flag set */
1696 && sender_host_address /* Not local input */
1697 && !f.sender_host_notsocket) /* Really is a socket */
1698 return BADSYN_CMD;
1699
1700 return OTHER_CMD;
1701 }
1702
1703
1704
1705 /*************************************************
1706 * Forced closedown of call *
1707 *************************************************/
1708
1709 /* This function is called from log.c when Exim is dying because of a serious
1710 disaster, and also from some other places. If an incoming non-batched SMTP
1711 channel is open, it swallows the rest of the incoming message if in the DATA
1712 phase, sends the reply string, and gives an error to all subsequent commands
1713 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1714 smtp_in.
1715
1716 Arguments:
1717 message SMTP reply string to send, excluding the code
1718
1719 Returns: nothing
1720 */
1721
1722 void
1723 smtp_closedown(uschar *message)
1724 {
1725 if (!smtp_in || smtp_batched_input) return;
1726 receive_swallow_smtp();
1727 smtp_printf("421 %s\r\n", FALSE, message);
1728
1729 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1730 {
1731 case EOF_CMD:
1732 return;
1733
1734 case QUIT_CMD:
1735 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1736 mac_smtp_fflush();
1737 return;
1738
1739 case RSET_CMD:
1740 smtp_printf("250 Reset OK\r\n", FALSE);
1741 break;
1742
1743 default:
1744 smtp_printf("421 %s\r\n", FALSE, message);
1745 break;
1746 }
1747 }
1748
1749
1750
1751
1752 /*************************************************
1753 * Set up connection info for logging *
1754 *************************************************/
1755
1756 /* This function is called when logging information about an SMTP connection.
1757 It sets up appropriate source information, depending on the type of connection.
1758 If sender_fullhost is NULL, we are at a very early stage of the connection;
1759 just use the IP address.
1760
1761 Argument: none
1762 Returns: a string describing the connection
1763 */
1764
1765 uschar *
1766 smtp_get_connection_info(void)
1767 {
1768 const uschar * hostname = sender_fullhost
1769 ? sender_fullhost : sender_host_address;
1770
1771 if (host_checking)
1772 return string_sprintf("SMTP connection from %s", hostname);
1773
1774 if (f.sender_host_unknown || f.sender_host_notsocket)
1775 return string_sprintf("SMTP connection from %s", sender_ident);
1776
1777 if (f.is_inetd)
1778 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1779
1780 if (LOGGING(incoming_interface) && interface_address)
1781 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1782 interface_address, interface_port);
1783
1784 return string_sprintf("SMTP connection from %s", hostname);
1785 }
1786
1787
1788
1789 #ifdef SUPPORT_TLS
1790 /* Append TLS-related information to a log line
1791
1792 Arguments:
1793 g String under construction: allocated string to extend, or NULL
1794
1795 Returns: Allocated string or NULL
1796 */
1797 static gstring *
1798 s_tlslog(gstring * g)
1799 {
1800 if (LOGGING(tls_cipher) && tls_in.cipher)
1801 g = string_append(g, 2, US" X=", tls_in.cipher);
1802 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1803 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1804 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1805 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1806 if (LOGGING(tls_sni) && tls_in.sni)
1807 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1808 return g;
1809 }
1810 #endif
1811
1812 /*************************************************
1813 * Log lack of MAIL if so configured *
1814 *************************************************/
1815
1816 /* This function is called when an SMTP session ends. If the log selector
1817 smtp_no_mail is set, write a log line giving some details of what has happened
1818 in the SMTP session.
1819
1820 Arguments: none
1821 Returns: nothing
1822 */
1823
1824 void
1825 smtp_log_no_mail(void)
1826 {
1827 int i;
1828 uschar * sep, * s;
1829 gstring * g = NULL;
1830
1831 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1832 return;
1833
1834 if (sender_host_authenticated)
1835 {
1836 g = string_append(g, 2, US" A=", sender_host_authenticated);
1837 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1838 }
1839
1840 #ifdef SUPPORT_TLS
1841 g = s_tlslog(g);
1842 #endif
1843
1844 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1845
1846 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1847 if (smtp_connection_had[i] != SCH_NONE)
1848 {
1849 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1850 sep = US",";
1851 }
1852
1853 for (i = 0; i < smtp_ch_index; i++)
1854 {
1855 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1856 sep = US",";
1857 }
1858
1859 if (!(s = string_from_gstring(g))) s = US"";
1860
1861 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1862 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1863 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1864 }
1865
1866
1867 /* Return list of recent smtp commands */
1868
1869 uschar *
1870 smtp_cmd_hist(void)
1871 {
1872 int i;
1873 gstring * list = NULL;
1874 uschar * s;
1875
1876 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1877 if (smtp_connection_had[i] != SCH_NONE)
1878 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1879
1880 for (i = 0; i < smtp_ch_index; i++)
1881 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1882
1883 s = string_from_gstring(list);
1884 return s ? s : US"";
1885 }
1886
1887
1888
1889
1890 /*************************************************
1891 * Check HELO line and set sender_helo_name *
1892 *************************************************/
1893
1894 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1895 the domain name of the sending host, or an ip literal in square brackets. The
1896 argument is placed in sender_helo_name, which is in malloc store, because it
1897 must persist over multiple incoming messages. If helo_accept_junk is set, this
1898 host is permitted to send any old junk (needed for some broken hosts).
1899 Otherwise, helo_allow_chars can be used for rogue characters in general
1900 (typically people want to let in underscores).
1901
1902 Argument:
1903 s the data portion of the line (already past any white space)
1904
1905 Returns: TRUE or FALSE
1906 */
1907
1908 static BOOL
1909 check_helo(uschar *s)
1910 {
1911 uschar *start = s;
1912 uschar *end = s + Ustrlen(s);
1913 BOOL yield = fl.helo_accept_junk;
1914
1915 /* Discard any previous helo name */
1916
1917 if (sender_helo_name)
1918 {
1919 store_free(sender_helo_name);
1920 sender_helo_name = NULL;
1921 }
1922
1923 /* Skip tests if junk is permitted. */
1924
1925 if (!yield)
1926
1927 /* Allow the new standard form for IPv6 address literals, namely,
1928 [IPv6:....], and because someone is bound to use it, allow an equivalent
1929 IPv4 form. Allow plain addresses as well. */
1930
1931 if (*s == '[')
1932 {
1933 if (end[-1] == ']')
1934 {
1935 end[-1] = 0;
1936 if (strncmpic(s, US"[IPv6:", 6) == 0)
1937 yield = (string_is_ip_address(s+6, NULL) == 6);
1938 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1939 yield = (string_is_ip_address(s+6, NULL) == 4);
1940 else
1941 yield = (string_is_ip_address(s+1, NULL) != 0);
1942 end[-1] = ']';
1943 }
1944 }
1945
1946 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1947 that have been configured (usually underscore - sigh). */
1948
1949 else if (*s)
1950 for (yield = TRUE; *s; s++)
1951 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1952 Ustrchr(helo_allow_chars, *s) == NULL)
1953 {
1954 yield = FALSE;
1955 break;
1956 }
1957
1958 /* Save argument if OK */
1959
1960 if (yield) sender_helo_name = string_copy_malloc(start);
1961 return yield;
1962 }
1963
1964
1965
1966
1967
1968 /*************************************************
1969 * Extract SMTP command option *
1970 *************************************************/
1971
1972 /* This function picks the next option setting off the end of smtp_cmd_data. It
1973 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1974 things that can appear there.
1975
1976 Arguments:
1977 name point this at the name
1978 value point this at the data string
1979
1980 Returns: TRUE if found an option
1981 */
1982
1983 static BOOL
1984 extract_option(uschar **name, uschar **value)
1985 {
1986 uschar *n;
1987 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1988 while (isspace(*v)) v--;
1989 v[1] = 0;
1990 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1991 {
1992 /* Take care to not stop at a space embedded in a quoted local-part */
1993
1994 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1995 v--;
1996 }
1997
1998 n = v;
1999 if (*v == '=')
2000 {
2001 while(isalpha(n[-1])) n--;
2002 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2003 if (!isspace(n[-1])) return FALSE;
2004 n[-1] = 0;
2005 }
2006 else
2007 {
2008 n++;
2009 if (v == smtp_cmd_data) return FALSE;
2010 }
2011 *v++ = 0;
2012 *name = n;
2013 *value = v;
2014 return TRUE;
2015 }
2016
2017
2018
2019
2020
2021 /*************************************************
2022 * Reset for new message *
2023 *************************************************/
2024
2025 /* This function is called whenever the SMTP session is reset from
2026 within either of the setup functions; also from the daemon loop.
2027
2028 Argument: the stacking pool storage reset point
2029 Returns: nothing
2030 */
2031
2032 void
2033 smtp_reset(void *reset_point)
2034 {
2035 recipients_list = NULL;
2036 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2037 raw_recipients_count = recipients_count = recipients_list_max = 0;
2038 message_linecount = 0;
2039 message_size = -1;
2040 acl_added_headers = NULL;
2041 acl_removed_headers = NULL;
2042 f.queue_only_policy = FALSE;
2043 rcpt_smtp_response = NULL;
2044 fl.rcpt_smtp_response_same = TRUE;
2045 fl.rcpt_in_progress = FALSE;
2046 f.deliver_freeze = FALSE; /* Can be set by ACL */
2047 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2048 fake_response = OK; /* Can be set by ACL */
2049 #ifdef WITH_CONTENT_SCAN
2050 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2051 #endif
2052 f.submission_mode = FALSE; /* Can be set by ACL */
2053 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2054 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2055 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2056 sending_ip_address = NULL;
2057 return_path = sender_address = NULL;
2058 sender_data = NULL; /* Can be set by ACL */
2059 deliver_localpart_parent = deliver_localpart_orig = NULL;
2060 deliver_domain_parent = deliver_domain_orig = NULL;
2061 callout_address = NULL;
2062 submission_name = NULL; /* Can be set by ACL */
2063 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2064 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2065 sender_verified_list = NULL; /* No senders verified */
2066 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2067 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2068
2069 authenticated_sender = NULL;
2070 #ifdef EXPERIMENTAL_BRIGHTMAIL
2071 bmi_run = 0;
2072 bmi_verdicts = NULL;
2073 #endif
2074 dnslist_domain = dnslist_matched = NULL;
2075 #ifdef SUPPORT_SPF
2076 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2077 spf_result_guessed = FALSE;
2078 #endif
2079 #ifndef DISABLE_DKIM
2080 dkim_cur_signer = dkim_signers =
2081 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2082 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2083 f.dkim_disable_verify = FALSE;
2084 dkim_collect_input = 0;
2085 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2086 dkim_key_length = 0;
2087 dkim_verify_signers = US"$dkim_signers";
2088 #endif
2089 #ifdef EXPERIMENTAL_DMARC
2090 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2091 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2092 dmarc_used_domain = NULL;
2093 #endif
2094 #ifdef EXPERIMENTAL_ARC
2095 arc_state = arc_state_reason = NULL;
2096 #endif
2097 dsn_ret = 0;
2098 dsn_envid = NULL;
2099 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2100 #ifndef DISABLE_PRDR
2101 prdr_requested = FALSE;
2102 #endif
2103 #ifdef SUPPORT_I18N
2104 message_smtputf8 = FALSE;
2105 #endif
2106 body_linecount = body_zerocount = 0;
2107
2108 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2109 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2110 /* Note that ratelimiters_conn persists across resets. */
2111
2112 /* Reset message ACL variables */
2113
2114 acl_var_m = NULL;
2115
2116 /* The message body variables use malloc store. They may be set if this is
2117 not the first message in an SMTP session and the previous message caused them
2118 to be referenced in an ACL. */
2119
2120 if (message_body)
2121 {
2122 store_free(message_body);
2123 message_body = NULL;
2124 }
2125
2126 if (message_body_end)
2127 {
2128 store_free(message_body_end);
2129 message_body_end = NULL;
2130 }
2131
2132 /* Warning log messages are also saved in malloc store. They are saved to avoid
2133 repetition in the same message, but it seems right to repeat them for different
2134 messages. */
2135
2136 while (acl_warn_logged)
2137 {
2138 string_item *this = acl_warn_logged;
2139 acl_warn_logged = acl_warn_logged->next;
2140 store_free(this);
2141 }
2142 store_reset(reset_point);
2143 }
2144
2145
2146
2147
2148
2149 /*************************************************
2150 * Initialize for incoming batched SMTP message *
2151 *************************************************/
2152
2153 /* This function is called from smtp_setup_msg() in the case when
2154 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2155 of messages in one file with SMTP commands between them. All errors must be
2156 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2157 relevant. After an error on a sender, or an invalid recipient, the remainder
2158 of the message is skipped. The value of received_protocol is already set.
2159
2160 Argument: none
2161 Returns: > 0 message successfully started (reached DATA)
2162 = 0 QUIT read or end of file reached
2163 < 0 should not occur
2164 */
2165
2166 static int
2167 smtp_setup_batch_msg(void)
2168 {
2169 int done = 0;
2170 void *reset_point = store_get(0);
2171
2172 /* Save the line count at the start of each transaction - single commands
2173 like HELO and RSET count as whole transactions. */
2174
2175 bsmtp_transaction_linecount = receive_linecount;
2176
2177 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2178
2179 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2180 smtp_reset(reset_point); /* Reset for start of message */
2181
2182 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2183 value. The values are 2 larger than the required yield of the function. */
2184
2185 while (done <= 0)
2186 {
2187 uschar *errmess;
2188 uschar *recipient = NULL;
2189 int start, end, sender_domain, recipient_domain;
2190
2191 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2192 {
2193 /* The HELO/EHLO commands set sender_address_helo if they have
2194 valid data; otherwise they are ignored, except that they do
2195 a reset of the state. */
2196
2197 case HELO_CMD:
2198 case EHLO_CMD:
2199
2200 check_helo(smtp_cmd_data);
2201 /* Fall through */
2202
2203 case RSET_CMD:
2204 cancel_cutthrough_connection(TRUE, US"RSET received");
2205 smtp_reset(reset_point);
2206 bsmtp_transaction_linecount = receive_linecount;
2207 break;
2208
2209
2210 /* The MAIL FROM command requires an address as an operand. All we
2211 do here is to parse it for syntactic correctness. The form "<>" is
2212 a special case which converts into an empty string. The start/end
2213 pointers in the original are not used further for this address, as
2214 it is the canonical extracted address which is all that is kept. */
2215
2216 case MAIL_CMD:
2217 smtp_mailcmd_count++; /* Count for no-mail log */
2218 if (sender_address != NULL)
2219 /* The function moan_smtp_batch() does not return. */
2220 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2221
2222 if (smtp_cmd_data[0] == 0)
2223 /* The function moan_smtp_batch() does not return. */
2224 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2225
2226 /* Reset to start of message */
2227
2228 cancel_cutthrough_connection(TRUE, US"MAIL received");
2229 smtp_reset(reset_point);
2230
2231 /* Apply SMTP rewrite */
2232
2233 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2234 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2235 US"", global_rewrite_rules) : smtp_cmd_data;
2236
2237 /* Extract the address; the TRUE flag allows <> as valid */
2238
2239 raw_sender =
2240 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2241 TRUE);
2242
2243 if (!raw_sender)
2244 /* The function moan_smtp_batch() does not return. */
2245 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2246
2247 sender_address = string_copy(raw_sender);
2248
2249 /* Qualify unqualified sender addresses if permitted to do so. */
2250
2251 if ( !sender_domain
2252 && sender_address[0] != 0 && sender_address[0] != '@')
2253 if (f.allow_unqualified_sender)
2254 {
2255 sender_address = rewrite_address_qualify(sender_address, FALSE);
2256 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2257 "and rewritten\n", raw_sender);
2258 }
2259 /* The function moan_smtp_batch() does not return. */
2260 else
2261 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2262 "a domain");
2263 break;
2264
2265
2266 /* The RCPT TO command requires an address as an operand. All we do
2267 here is to parse it for syntactic correctness. There may be any number
2268 of RCPT TO commands, specifying multiple senders. We build them all into
2269 a data structure that is in argc/argv format. The start/end values
2270 given by parse_extract_address are not used, as we keep only the
2271 extracted address. */
2272
2273 case RCPT_CMD:
2274 if (!sender_address)
2275 /* The function moan_smtp_batch() does not return. */
2276 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2277
2278 if (smtp_cmd_data[0] == 0)
2279 /* The function moan_smtp_batch() does not return. */
2280 moan_smtp_batch(smtp_cmd_buffer,
2281 "501 RCPT TO must have an address operand");
2282
2283 /* Check maximum number allowed */
2284
2285 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2286 /* The function moan_smtp_batch() does not return. */
2287 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2288 recipients_max_reject? "552": "452");
2289
2290 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2291 recipient address */
2292
2293 recipient = rewrite_existflags & rewrite_smtp
2294 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2295 global_rewrite_rules)
2296 : smtp_cmd_data;
2297
2298 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2299 &recipient_domain, FALSE);
2300
2301 if (!recipient)
2302 /* The function moan_smtp_batch() does not return. */
2303 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2304
2305 /* If the recipient address is unqualified, qualify it if permitted. Then
2306 add it to the list of recipients. */
2307
2308 if (!recipient_domain)
2309 if (f.allow_unqualified_recipient)
2310 {
2311 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2312 recipient);
2313 recipient = rewrite_address_qualify(recipient, TRUE);
2314 }
2315 /* The function moan_smtp_batch() does not return. */
2316 else
2317 moan_smtp_batch(smtp_cmd_buffer,
2318 "501 recipient address must contain a domain");
2319
2320 receive_add_recipient(recipient, -1);
2321 break;
2322
2323
2324 /* The DATA command is legal only if it follows successful MAIL FROM
2325 and RCPT TO commands. This function is complete when a valid DATA
2326 command is encountered. */
2327
2328 case DATA_CMD:
2329 if (!sender_address || recipients_count <= 0)
2330 /* The function moan_smtp_batch() does not return. */
2331 if (!sender_address)
2332 moan_smtp_batch(smtp_cmd_buffer,
2333 "503 MAIL FROM:<sender> command must precede DATA");
2334 else
2335 moan_smtp_batch(smtp_cmd_buffer,
2336 "503 RCPT TO:<recipient> must precede DATA");
2337 else
2338 {
2339 done = 3; /* DATA successfully achieved */
2340 message_ended = END_NOTENDED; /* Indicate in middle of message */
2341 }
2342 break;
2343
2344
2345 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2346
2347 case VRFY_CMD:
2348 case EXPN_CMD:
2349 case HELP_CMD:
2350 case NOOP_CMD:
2351 case ETRN_CMD:
2352 bsmtp_transaction_linecount = receive_linecount;
2353 break;
2354
2355
2356 case EOF_CMD:
2357 case QUIT_CMD:
2358 done = 2;
2359 break;
2360
2361
2362 case BADARG_CMD:
2363 /* The function moan_smtp_batch() does not return. */
2364 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2365 break;
2366
2367
2368 case BADCHAR_CMD:
2369 /* The function moan_smtp_batch() does not return. */
2370 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2371 break;
2372
2373
2374 default:
2375 /* The function moan_smtp_batch() does not return. */
2376 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2377 break;
2378 }
2379 }
2380
2381 return done - 2; /* Convert yield values */
2382 }
2383
2384
2385
2386
2387 #ifdef SUPPORT_TLS
2388 static BOOL
2389 smtp_log_tls_fail(uschar * errstr)
2390 {
2391 uschar * conn_info = smtp_get_connection_info();
2392
2393 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2394 /* I'd like to get separated H= here, but too hard for now */
2395
2396 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2397 return FALSE;
2398 }
2399 #endif
2400
2401
2402
2403
2404 #ifdef TCP_FASTOPEN
2405 static void
2406 tfo_in_check(void)
2407 {
2408 # ifdef TCP_INFO
2409 struct tcp_info tinfo;
2410 socklen_t len = sizeof(tinfo);
2411
2412 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2413 #ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11 does not seem to have this yet */
2414 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2415 {
2416 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (ACKd data-on-SYN)\n");
2417 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2418 }
2419 else
2420 #endif
2421 if (tinfo.tcpi_state == TCP_SYN_RECV)
2422 {
2423 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2424 f.tcp_in_fastopen = TRUE;
2425 }
2426 # endif
2427 }
2428 #endif
2429
2430
2431 /*************************************************
2432 * Start an SMTP session *
2433 *************************************************/
2434
2435 /* This function is called at the start of an SMTP session. Thereafter,
2436 smtp_setup_msg() is called to initiate each separate message. This
2437 function does host-specific testing, and outputs the banner line.
2438
2439 Arguments: none
2440 Returns: FALSE if the session can not continue; something has
2441 gone wrong, or the connection to the host is blocked
2442 */
2443
2444 BOOL
2445 smtp_start_session(void)
2446 {
2447 int esclen;
2448 uschar *user_msg, *log_msg;
2449 uschar *code, *esc;
2450 uschar *p, *s;
2451 gstring * ss;
2452
2453 gettimeofday(&smtp_connection_start, NULL);
2454 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2455 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2456 smtp_ch_index = 0;
2457
2458 /* Default values for certain variables */
2459
2460 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2461 smtp_mailcmd_count = 0;
2462 count_nonmail = TRUE_UNSET;
2463 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2464 smtp_delay_mail = smtp_rlm_base;
2465 fl.auth_advertised = FALSE;
2466 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2467 f.pipelining_enable = TRUE;
2468 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2469 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2470
2471 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2472 authentication settings from -oMaa to remain in force. */
2473
2474 if (!host_checking && !f.sender_host_notsocket)
2475 sender_host_auth_pubname = sender_host_authenticated = NULL;
2476 authenticated_by = NULL;
2477
2478 #ifdef SUPPORT_TLS
2479 tls_in.cipher = tls_in.peerdn = NULL;
2480 tls_in.ourcert = tls_in.peercert = NULL;
2481 tls_in.sni = NULL;
2482 tls_in.ocsp = OCSP_NOT_REQ;
2483 fl.tls_advertised = FALSE;
2484 # ifdef EXPERIMENTAL_REQUIRETLS
2485 fl.requiretls_advertised = FALSE;
2486 # endif
2487 #endif
2488 fl.dsn_advertised = FALSE;
2489 #ifdef SUPPORT_I18N
2490 fl.smtputf8_advertised = FALSE;
2491 #endif
2492
2493 /* Reset ACL connection variables */
2494
2495 acl_var_c = NULL;
2496
2497 /* Allow for trailing 0 in the command and data buffers. */
2498
2499 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2500 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2501 "malloc() failed for SMTP command buffer");
2502
2503 smtp_cmd_buffer[0] = 0;
2504 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2505
2506 /* For batched input, the protocol setting can be overridden from the
2507 command line by a trusted caller. */
2508
2509 if (smtp_batched_input)
2510 {
2511 if (!received_protocol) received_protocol = US"local-bsmtp";
2512 }
2513
2514 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2515 reset later if any of EHLO/AUTH/STARTTLS are received. */
2516
2517 else
2518 received_protocol =
2519 (sender_host_address ? protocols : protocols_local) [pnormal];
2520
2521 /* Set up the buffer for inputting using direct read() calls, and arrange to
2522 call the local functions instead of the standard C ones. Place a NUL at the
2523 end of the buffer to safety-stop C-string reads from it. */
2524
2525 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2526 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2527 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2528
2529 receive_getc = smtp_getc;
2530 receive_getbuf = smtp_getbuf;
2531 receive_get_cache = smtp_get_cache;
2532 receive_ungetc = smtp_ungetc;
2533 receive_feof = smtp_feof;
2534 receive_ferror = smtp_ferror;
2535 receive_smtp_buffered = smtp_buffered;
2536 smtp_inptr = smtp_inend = smtp_inbuffer;
2537 smtp_had_eof = smtp_had_error = 0;
2538
2539 /* Set up the message size limit; this may be host-specific */
2540
2541 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2542 if (expand_string_message)
2543 {
2544 if (thismessage_size_limit == -1)
2545 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2546 "%s", expand_string_message);
2547 else
2548 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2549 "%s", expand_string_message);
2550 smtp_closedown(US"Temporary local problem - please try later");
2551 return FALSE;
2552 }
2553
2554 /* When a message is input locally via the -bs or -bS options, sender_host_
2555 unknown is set unless -oMa was used to force an IP address, in which case it
2556 is checked like a real remote connection. When -bs is used from inetd, this
2557 flag is not set, causing the sending host to be checked. The code that deals
2558 with IP source routing (if configured) is never required for -bs or -bS and
2559 the flag sender_host_notsocket is used to suppress it.
2560
2561 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2562 reserve for certain hosts and/or networks. */
2563
2564 if (!f.sender_host_unknown)
2565 {
2566 int rc;
2567 BOOL reserved_host = FALSE;
2568
2569 /* Look up IP options (source routing info) on the socket if this is not an
2570 -oMa "host", and if any are found, log them and drop the connection.
2571
2572 Linux (and others now, see below) is different to everyone else, so there
2573 has to be some conditional compilation here. Versions of Linux before 2.1.15
2574 used a structure whose name was "options". Somebody finally realized that
2575 this name was silly, and it got changed to "ip_options". I use the
2576 newer name here, but there is a fudge in the script that sets up os.h
2577 to define a macro in older Linux systems.
2578
2579 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2580 glibc 2, which has chosen ip_opts for the structure name. This is now
2581 really a glibc thing rather than a Linux thing, so the condition name
2582 has been changed to reflect this. It is relevant also to GNU/Hurd.
2583
2584 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2585 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2586 a special macro defined in the os.h file.
2587
2588 Some DGUX versions on older hardware appear not to support IP options at
2589 all, so there is now a general macro which can be set to cut out this
2590 support altogether.
2591
2592 How to do this properly in IPv6 is not yet known. */
2593
2594 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2595
2596 #ifdef GLIBC_IP_OPTIONS
2597 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2598 #define OPTSTYLE 1
2599 #else
2600 #define OPTSTYLE 2
2601 #endif
2602 #elif defined DARWIN_IP_OPTIONS
2603 #define OPTSTYLE 2
2604 #else
2605 #define OPTSTYLE 3
2606 #endif
2607
2608 if (!host_checking && !f.sender_host_notsocket)
2609 {
2610 #if OPTSTYLE == 1
2611 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2612 struct ip_options *ipopt = store_get(optlen);
2613 #elif OPTSTYLE == 2
2614 struct ip_opts ipoptblock;
2615 struct ip_opts *ipopt = &ipoptblock;
2616 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2617 #else
2618 struct ipoption ipoptblock;
2619 struct ipoption *ipopt = &ipoptblock;
2620 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2621 #endif
2622
2623 /* Occasional genuine failures of getsockopt() have been seen - for
2624 example, "reset by peer". Therefore, just log and give up on this
2625 call, unless the error is ENOPROTOOPT. This error is given by systems
2626 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2627 of writing. So for that error, carry on - we just can't do an IP options
2628 check. */
2629
2630 DEBUG(D_receive) debug_printf("checking for IP options\n");
2631
2632 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2633 &optlen) < 0)
2634 {
2635 if (errno != ENOPROTOOPT)
2636 {
2637 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2638 host_and_ident(FALSE), strerror(errno));
2639 smtp_printf("451 SMTP service not available\r\n", FALSE);
2640 return FALSE;
2641 }
2642 }
2643
2644 /* Deal with any IP options that are set. On the systems I have looked at,
2645 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2646 more logging data than will fit in big_buffer. Nevertheless, after somebody
2647 questioned this code, I've added in some paranoid checking. */
2648
2649 else if (optlen > 0)
2650 {
2651 uschar *p = big_buffer;
2652 uschar *pend = big_buffer + big_buffer_size;
2653 uschar *opt, *adptr;
2654 int optcount;
2655 struct in_addr addr;
2656
2657 #if OPTSTYLE == 1
2658 uschar *optstart = US (ipopt->__data);
2659 #elif OPTSTYLE == 2
2660 uschar *optstart = US (ipopt->ip_opts);
2661 #else
2662 uschar *optstart = US (ipopt->ipopt_list);
2663 #endif
2664
2665 DEBUG(D_receive) debug_printf("IP options exist\n");
2666
2667 Ustrcpy(p, "IP options on incoming call:");
2668 p += Ustrlen(p);
2669
2670 for (opt = optstart; opt != NULL &&
2671 opt < US (ipopt) + optlen;)
2672 {
2673 switch (*opt)
2674 {
2675 case IPOPT_EOL:
2676 opt = NULL;
2677 break;
2678
2679 case IPOPT_NOP:
2680 opt++;
2681 break;
2682
2683 case IPOPT_SSRR:
2684 case IPOPT_LSRR:
2685 if (!string_format(p, pend-p, " %s [@%s",
2686 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2687 #if OPTSTYLE == 1
2688 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2689 #elif OPTSTYLE == 2
2690 inet_ntoa(ipopt->ip_dst)))
2691 #else
2692 inet_ntoa(ipopt->ipopt_dst)))
2693 #endif
2694 {
2695 opt = NULL;
2696 break;
2697 }
2698
2699 p += Ustrlen(p);
2700 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2701 adptr = opt + 3;
2702 while (optcount-- > 0)
2703 {
2704 memcpy(&addr, adptr, sizeof(addr));
2705 if (!string_format(p, pend - p - 1, "%s%s",
2706 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2707 {
2708 opt = NULL;
2709 break;
2710 }
2711 p += Ustrlen(p);
2712 adptr += sizeof(struct in_addr);
2713 }
2714 *p++ = ']';
2715 opt += opt[1];
2716 break;
2717
2718 default:
2719 {
2720 int i;
2721 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2722 Ustrcat(p, "[ ");
2723 p += 2;
2724 for (i = 0; i < opt[1]; i++)
2725 p += sprintf(CS p, "%2.2x ", opt[i]);
2726 *p++ = ']';
2727 }
2728 opt += opt[1];
2729 break;
2730 }
2731 }
2732
2733 *p = 0;
2734 log_write(0, LOG_MAIN, "%s", big_buffer);
2735
2736 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2737
2738 log_write(0, LOG_MAIN|LOG_REJECT,
2739 "connection from %s refused (IP options)", host_and_ident(FALSE));
2740
2741 smtp_printf("554 SMTP service not available\r\n", FALSE);
2742 return FALSE;
2743 }
2744
2745 /* Length of options = 0 => there are no options */
2746
2747 else DEBUG(D_receive) debug_printf("no IP options found\n");
2748 }
2749 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2750
2751 /* Set keep-alive in socket options. The option is on by default. This
2752 setting is an attempt to get rid of some hanging connections that stick in
2753 read() when the remote end (usually a dialup) goes away. */
2754
2755 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2756 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2757
2758 /* If the current host matches host_lookup, set the name by doing a
2759 reverse lookup. On failure, sender_host_name will be NULL and
2760 host_lookup_failed will be TRUE. This may or may not be serious - optional
2761 checks later. */
2762
2763 if (verify_check_host(&host_lookup) == OK)
2764 {
2765 (void)host_name_lookup();
2766 host_build_sender_fullhost();
2767 }
2768
2769 /* Delay this until we have the full name, if it is looked up. */
2770
2771 set_process_info("handling incoming connection from %s",
2772 host_and_ident(FALSE));
2773
2774 /* Expand smtp_receive_timeout, if needed */
2775
2776 if (smtp_receive_timeout_s)
2777 {
2778 uschar * exp;
2779 if ( !(exp = expand_string(smtp_receive_timeout_s))
2780 || !(*exp)
2781 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2782 )
2783 log_write(0, LOG_MAIN|LOG_PANIC,
2784 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2785 }
2786
2787 /* Test for explicit connection rejection */
2788
2789 if (verify_check_host(&host_reject_connection) == OK)
2790 {
2791 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2792 "from %s (host_reject_connection)", host_and_ident(FALSE));
2793 smtp_printf("554 SMTP service not available\r\n", FALSE);
2794 return FALSE;
2795 }
2796
2797 /* Test with TCP Wrappers if so configured. There is a problem in that
2798 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2799 such as disks dying. In these cases, it is desirable to reject with a 4xx
2800 error instead of a 5xx error. There isn't a "right" way to detect such
2801 problems. The following kludge is used: errno is zeroed before calling
2802 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2803 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2804 not exist). */
2805
2806 #ifdef USE_TCP_WRAPPERS
2807 errno = 0;
2808 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2809 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2810 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2811 expand_string_message);
2812
2813 if (!hosts_ctl(tcp_wrappers_name,
2814 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2815 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2816 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2817 {
2818 if (errno == 0 || errno == ENOENT)
2819 {
2820 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2821 log_write(L_connection_reject,
2822 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2823 "(tcp wrappers)", host_and_ident(FALSE));
2824 smtp_printf("554 SMTP service not available\r\n", FALSE);
2825 }
2826 else
2827 {
2828 int save_errno = errno;
2829 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2830 "errno value %d\n", save_errno);
2831 log_write(L_connection_reject,
2832 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2833 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2834 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2835 }
2836 return FALSE;
2837 }
2838 #endif
2839
2840 /* Check for reserved slots. The value of smtp_accept_count has already been
2841 incremented to include this process. */
2842
2843 if (smtp_accept_max > 0 &&
2844 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2845 {
2846 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2847 {
2848 log_write(L_connection_reject,
2849 LOG_MAIN, "temporarily refused connection from %s: not in "
2850 "reserve list: connected=%d max=%d reserve=%d%s",
2851 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2852 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2853 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2854 "please try again later\r\n", FALSE, smtp_active_hostname);
2855 return FALSE;
2856 }
2857 reserved_host = TRUE;
2858 }
2859
2860 /* If a load level above which only messages from reserved hosts are
2861 accepted is set, check the load. For incoming calls via the daemon, the
2862 check is done in the superior process if there are no reserved hosts, to
2863 save a fork. In all cases, the load average will already be available
2864 in a global variable at this point. */
2865
2866 if (smtp_load_reserve >= 0 &&
2867 load_average > smtp_load_reserve &&
2868 !reserved_host &&
2869 verify_check_host(&smtp_reserve_hosts) != OK)
2870 {
2871 log_write(L_connection_reject,
2872 LOG_MAIN, "temporarily refused connection from %s: not in "
2873 "reserve list and load average = %.2f", host_and_ident(FALSE),
2874 (double)load_average/1000.0);
2875 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2876 smtp_active_hostname);
2877 return FALSE;
2878 }
2879
2880 /* Determine whether unqualified senders or recipients are permitted
2881 for this host. Unfortunately, we have to do this every time, in order to
2882 set the flags so that they can be inspected when considering qualifying
2883 addresses in the headers. For a site that permits no qualification, this
2884 won't take long, however. */
2885
2886 f.allow_unqualified_sender =
2887 verify_check_host(&sender_unqualified_hosts) == OK;
2888
2889 f.allow_unqualified_recipient =
2890 verify_check_host(&recipient_unqualified_hosts) == OK;
2891
2892 /* Determine whether HELO/EHLO is required for this host. The requirement
2893 can be hard or soft. */
2894
2895 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2896 if (!fl.helo_required)
2897 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2898
2899 /* Determine whether this hosts is permitted to send syntactic junk
2900 after a HELO or EHLO command. */
2901
2902 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2903 }
2904
2905 /* For batch SMTP input we are now done. */
2906
2907 if (smtp_batched_input) return TRUE;
2908
2909 /* If valid Proxy Protocol source is connecting, set up session.
2910 * Failure will not allow any SMTP function other than QUIT. */
2911
2912 #ifdef SUPPORT_PROXY
2913 proxy_session = FALSE;
2914 f.proxy_session_failed = FALSE;
2915 if (check_proxy_protocol_host())
2916 setup_proxy_protocol_host();
2917 #endif
2918
2919 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2920 smtps port for use with older style SSL MTAs. */
2921
2922 #ifdef SUPPORT_TLS
2923 if (tls_in.on_connect)
2924 {
2925 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2926 return smtp_log_tls_fail(user_msg);
2927 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2928 }
2929 #endif
2930
2931 /* Run the connect ACL if it exists */
2932
2933 user_msg = NULL;
2934 if (acl_smtp_connect)
2935 {
2936 int rc;
2937 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2938 &log_msg)) != OK)
2939 {
2940 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2941 return FALSE;
2942 }
2943 }
2944
2945 /* Output the initial message for a two-way SMTP connection. It may contain
2946 newlines, which then cause a multi-line response to be given. */
2947
2948 code = US"220"; /* Default status code */
2949 esc = US""; /* Default extended status code */
2950 esclen = 0; /* Length of esc */
2951
2952 if (!user_msg)
2953 {
2954 if (!(s = expand_string(smtp_banner)))
2955 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2956 "failed: %s", smtp_banner, expand_string_message);
2957 }
2958 else
2959 {
2960 int codelen = 3;
2961 s = user_msg;
2962 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2963 if (codelen > 4)
2964 {
2965 esc = code + 4;
2966 esclen = codelen - 4;
2967 }
2968 }
2969
2970 /* Remove any terminating newlines; might as well remove trailing space too */
2971
2972 p = s + Ustrlen(s);
2973 while (p > s && isspace(p[-1])) p--;
2974 *p = 0;
2975
2976 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2977 is all contained in a single IP packet. The original code wrote out the
2978 greeting using several calls to fprint/fputc, and on busy servers this could
2979 cause it to be split over more than one packet - which caused CC:Mail to fall
2980 over when it got the second part of the greeting after sending its first
2981 command. Sigh. To try to avoid this, build the complete greeting message
2982 first, and output it in one fell swoop. This gives a better chance of it
2983 ending up as a single packet. */
2984
2985 ss = string_get(256);
2986
2987 p = s;
2988 do /* At least once, in case we have an empty string */
2989 {
2990 int len;
2991 uschar *linebreak = Ustrchr(p, '\n');
2992 ss = string_catn(ss, code, 3);
2993 if (!linebreak)
2994 {
2995 len = Ustrlen(p);
2996 ss = string_catn(ss, US" ", 1);
2997 }
2998 else
2999 {
3000 len = linebreak - p;
3001 ss = string_catn(ss, US"-", 1);
3002 }
3003 ss = string_catn(ss, esc, esclen);
3004 ss = string_catn(ss, p, len);
3005 ss = string_catn(ss, US"\r\n", 2);
3006 p += len;
3007 if (linebreak) p++;
3008 }
3009 while (*p);
3010
3011 /* Before we write the banner, check that there is no input pending, unless
3012 this synchronisation check is disabled. */
3013
3014 #ifdef EXPERIMENTAL_PIPE_CONNECT
3015 fl.pipe_connect_acceptable =
3016 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3017
3018 if (!check_sync())
3019 if (fl.pipe_connect_acceptable)
3020 f.smtp_in_early_pipe_used = TRUE;
3021 else
3022 #else
3023 if (!check_sync())
3024 #endif
3025 {
3026 unsigned n = smtp_inend - smtp_inptr;
3027 if (n > 32) n = 32;
3028
3029 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3030 "synchronization error (input sent without waiting for greeting): "
3031 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3032 string_printing(string_copyn(smtp_inptr, n)));
3033 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3034 return FALSE;
3035 }
3036
3037 /* Now output the banner */
3038 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3039
3040 smtp_printf("%s",
3041 #ifdef EXPERIMENTAL_PIPE_CONNECT
3042 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3043 #else
3044 FALSE,
3045 #endif
3046 string_from_gstring(ss));
3047
3048 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3049 handshake arrived. If so we must have managed a TFO. */
3050
3051 #ifdef TCP_FASTOPEN
3052 tfo_in_check();
3053 #endif
3054
3055 return TRUE;
3056 }
3057
3058
3059
3060
3061
3062 /*************************************************
3063 * Handle SMTP syntax and protocol errors *
3064 *************************************************/
3065
3066 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3067 to do so. Then transmit the error response. The return value depends on the
3068 number of syntax and protocol errors in this SMTP session.
3069
3070 Arguments:
3071 type error type, given as a log flag bit
3072 code response code; <= 0 means don't send a response
3073 data data to reflect in the response (can be NULL)
3074 errmess the error message
3075
3076 Returns: -1 limit of syntax/protocol errors NOT exceeded
3077 +1 limit of syntax/protocol errors IS exceeded
3078
3079 These values fit in with the values of the "done" variable in the main
3080 processing loop in smtp_setup_msg(). */
3081
3082 static int
3083 synprot_error(int type, int code, uschar *data, uschar *errmess)
3084 {
3085 int yield = -1;
3086
3087 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3088 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3089 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3090
3091 if (++synprot_error_count > smtp_max_synprot_errors)
3092 {
3093 yield = 1;
3094 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3095 "syntax or protocol errors (last command was \"%s\")",
3096 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3097 }
3098
3099 if (code > 0)
3100 {
3101 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3102 data ? data : US"", data ? US": " : US"", errmess);
3103 if (yield == 1)
3104 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3105 }
3106
3107 return yield;
3108 }
3109
3110
3111
3112
3113 /*************************************************
3114 * Send SMTP response, possibly multiline *
3115 *************************************************/
3116
3117 /* There are, it seems, broken clients out there that cannot handle multiline
3118 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3119 output nothing for non-final calls, and only the first line for anything else.
3120
3121 Arguments:
3122 code SMTP code, may involve extended status codes
3123 codelen length of smtp code; if > 4 there's an ESC
3124 final FALSE if the last line isn't the final line
3125 msg message text, possibly containing newlines
3126
3127 Returns: nothing
3128 */
3129
3130 void
3131 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3132 {
3133 int esclen = 0;
3134 uschar *esc = US"";
3135
3136 if (!final && f.no_multiline_responses) return;
3137
3138 if (codelen > 4)
3139 {
3140 esc = code + 4;
3141 esclen = codelen - 4;
3142 }
3143
3144 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3145 have had the same. Note: this code is also present in smtp_printf(). It would
3146 be tidier to have it only in one place, but when it was added, it was easier to
3147 do it that way, so as not to have to mess with the code for the RCPT command,
3148 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3149
3150 if (fl.rcpt_in_progress)
3151 {
3152 if (rcpt_smtp_response == NULL)
3153 rcpt_smtp_response = string_copy(msg);
3154 else if (fl.rcpt_smtp_response_same &&
3155 Ustrcmp(rcpt_smtp_response, msg) != 0)
3156 fl.rcpt_smtp_response_same = FALSE;
3157 fl.rcpt_in_progress = FALSE;
3158 }
3159
3160 /* Now output the message, splitting it up into multiple lines if necessary.
3161 We only handle pipelining these responses as far as nonfinal/final groups,
3162 not the whole MAIL/RCPT/DATA response set. */
3163
3164 for (;;)
3165 {
3166 uschar *nl = Ustrchr(msg, '\n');
3167 if (nl == NULL)
3168 {
3169 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3170 return;
3171 }
3172 else if (nl[1] == 0 || f.no_multiline_responses)
3173 {
3174 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3175 (int)(nl - msg), msg);
3176 return;
3177 }
3178 else
3179 {
3180 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3181 msg = nl + 1;
3182 while (isspace(*msg)) msg++;
3183 }
3184 }
3185 }
3186
3187
3188
3189
3190 /*************************************************
3191 * Parse user SMTP message *
3192 *************************************************/
3193
3194 /* This function allows for user messages overriding the response code details
3195 by providing a suitable response code string at the start of the message
3196 user_msg. Check the message for starting with a response code and optionally an
3197 extended status code. If found, check that the first digit is valid, and if so,
3198 change the code pointer and length to use the replacement. An invalid code
3199 causes a panic log; in this case, if the log messages is the same as the user
3200 message, we must also adjust the value of the log message to show the code that
3201 is actually going to be used (the original one).
3202
3203 This function is global because it is called from receive.c as well as within
3204 this module.
3205
3206 Note that the code length returned includes the terminating whitespace
3207 character, which is always included in the regex match.
3208
3209 Arguments:
3210 code SMTP code, may involve extended status codes
3211 codelen length of smtp code; if > 4 there's an ESC
3212 msg message text
3213 log_msg optional log message, to be adjusted with the new SMTP code
3214 check_valid if true, verify the response code
3215
3216 Returns: nothing
3217 */
3218
3219 void
3220 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3221 BOOL check_valid)
3222 {
3223 int n;
3224 int ovector[3];
3225
3226 if (!msg || !*msg) return;
3227
3228 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3229 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3230
3231 if (check_valid && (*msg)[0] != (*code)[0])
3232 {
3233 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3234 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3235 if (log_msg != NULL && *log_msg == *msg)
3236 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3237 }
3238 else
3239 {
3240 *code = *msg;
3241 *codelen = ovector[1]; /* Includes final space */
3242 }
3243 *msg += ovector[1]; /* Chop the code off the message */
3244 return;
3245 }
3246
3247
3248
3249
3250 /*************************************************
3251 * Handle an ACL failure *
3252 *************************************************/
3253
3254 /* This function is called when acl_check() fails. As well as calls from within
3255 this module, it is called from receive.c for an ACL after DATA. It sorts out
3256 logging the incident, and sends the error response. A message containing
3257 newlines is turned into a multiline SMTP response, but for logging, only the
3258 first line is used.
3259
3260 There's a table of default permanent failure response codes to use in
3261 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3262 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3263 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3264 state, because there are broken clients that try VRFY before RCPT. A 5xx
3265 response should be given only when the address is positively known to be
3266 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3267 no explicit code, but if there is one we let it know best.
3268 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3269
3270 From Exim 4.63, it is possible to override the response code details by
3271 providing a suitable response code string at the start of the message provided
3272 in user_msg. The code's first digit is checked for validity.
3273
3274 Arguments:
3275 where where the ACL was called from
3276 rc the failure code
3277 user_msg a message that can be included in an SMTP response
3278 log_msg a message for logging
3279
3280 Returns: 0 in most cases
3281 2 if the failure code was FAIL_DROP, in which case the
3282 SMTP connection should be dropped (this value fits with the
3283 "done" variable in smtp_setup_msg() below)
3284 */
3285
3286 int
3287 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3288 {
3289 BOOL drop = rc == FAIL_DROP;
3290 int codelen = 3;
3291 uschar *smtp_code;
3292 uschar *lognl;
3293 uschar *sender_info = US"";
3294 uschar *what =
3295 #ifdef WITH_CONTENT_SCAN
3296 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3297 #endif
3298 where == ACL_WHERE_PREDATA ? US"DATA" :
3299 where == ACL_WHERE_DATA ? US"after DATA" :
3300 #ifndef DISABLE_PRDR
3301 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3302 #endif
3303 smtp_cmd_data ?
3304 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3305 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3306
3307 if (drop) rc = FAIL;
3308
3309 /* Set the default SMTP code, and allow a user message to change it. */
3310
3311 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3312 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3313 where != ACL_WHERE_VRFY);
3314
3315 /* We used to have sender_address here; however, there was a bug that was not
3316 updating sender_address after a rewrite during a verify. When this bug was
3317 fixed, sender_address at this point became the rewritten address. I'm not sure
3318 this is what should be logged, so I've changed to logging the unrewritten
3319 address to retain backward compatibility. */
3320
3321 #ifndef WITH_CONTENT_SCAN
3322 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3323 #else
3324 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3325 #endif
3326 {
3327 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3328 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3329 sender_host_authenticated ? US" A=" : US"",
3330 sender_host_authenticated ? sender_host_authenticated : US"",
3331 sender_host_authenticated && authenticated_id ? US":" : US"",
3332 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3333 );
3334 }
3335
3336 /* If there's been a sender verification failure with a specific message, and
3337 we have not sent a response about it yet, do so now, as a preliminary line for
3338 failures, but not defers. However, always log it for defer, and log it for fail
3339 unless the sender_verify_fail log selector has been turned off. */
3340
3341 if (sender_verified_failed &&
3342 !testflag(sender_verified_failed, af_sverify_told))
3343 {
3344 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3345 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3346
3347 setflag(sender_verified_failed, af_sverify_told);
3348
3349 if (rc != FAIL || LOGGING(sender_verify_fail))
3350 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3351 host_and_ident(TRUE),
3352 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3353 sender_verified_failed->address,
3354 (sender_verified_failed->message == NULL)? US"" :
3355 string_sprintf(": %s", sender_verified_failed->message));
3356
3357 if (rc == FAIL && sender_verified_failed->user_message)
3358 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3359 testflag(sender_verified_failed, af_verify_pmfail)?
3360 "Postmaster verification failed while checking <%s>\n%s\n"
3361 "Several RFCs state that you are required to have a postmaster\n"
3362 "mailbox for each mail domain. This host does not accept mail\n"
3363 "from domains whose servers reject the postmaster address."
3364 :
3365 testflag(sender_verified_failed, af_verify_nsfail)?
3366 "Callback setup failed while verifying <%s>\n%s\n"
3367 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3368 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3369 "RFC requirements, and stops you from receiving standard bounce\n"
3370 "messages. This host does not accept mail from domains whose servers\n"
3371 "refuse bounces."
3372 :
3373 "Verification failed for <%s>\n%s",
3374 sender_verified_failed->address,
3375 sender_verified_failed->user_message));
3376
3377 fl.rcpt_in_progress = save_rcpt_in_progress;
3378 }
3379
3380 /* Sort out text for logging */
3381
3382 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3383 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3384
3385 /* Send permanent failure response to the command, but the code used isn't
3386 always a 5xx one - see comments at the start of this function. If the original
3387 rc was FAIL_DROP we drop the connection and yield 2. */
3388
3389 if (rc == FAIL)
3390 smtp_respond(smtp_code, codelen, TRUE,
3391 user_msg ? user_msg : US"Administrative prohibition");
3392
3393 /* Send temporary failure response to the command. Don't give any details,
3394 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3395 verb, and for a header verify when smtp_return_error_details is set.
3396
3397 This conditional logic is all somewhat of a mess because of the odd
3398 interactions between temp_details and return_error_details. One day it should
3399 be re-implemented in a tidier fashion. */
3400
3401 else
3402 if (f.acl_temp_details && user_msg)
3403 {
3404 if ( smtp_return_error_details
3405 && sender_verified_failed
3406 && sender_verified_failed->message
3407 )
3408 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3409
3410 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3411 }
3412 else
3413 smtp_respond(smtp_code, codelen, TRUE,
3414 US"Temporary local problem - please try later");
3415
3416 /* Log the incident to the logs that are specified by log_reject_target
3417 (default main, reject). This can be empty to suppress logging of rejections. If
3418 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3419 is closing if required and return 2. */
3420
3421 if (log_reject_target != 0)
3422 {
3423 #ifdef SUPPORT_TLS
3424 gstring * g = s_tlslog(NULL);
3425 uschar * tls = string_from_gstring(g);
3426 if (!tls) tls = US"";
3427 #else
3428 uschar * tls = US"";
3429 #endif
3430 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3431 log_reject_target, "%s%s%s %s%srejected %s%s",
3432 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3433 host_and_ident(TRUE),
3434 tls,
3435 sender_info,
3436 rc == FAIL ? US"" : US"temporarily ",
3437 what, log_msg);
3438 }
3439
3440 if (!drop) return 0;
3441
3442 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3443 smtp_get_connection_info());
3444
3445 /* Run the not-quit ACL, but without any custom messages. This should not be a
3446 problem, because we get here only if some other ACL has issued "drop", and
3447 in that case, *its* custom messages will have been used above. */
3448
3449 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3450 return 2;
3451 }
3452
3453
3454
3455
3456 /*************************************************
3457 * Handle SMTP exit when QUIT is not given *
3458 *************************************************/
3459
3460 /* This function provides a logging/statistics hook for when an SMTP connection
3461 is dropped on the floor or the other end goes away. It's a global function
3462 because it's called from receive.c as well as this module. As well as running
3463 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3464 response, either with a custom message from the ACL, or using a default. There
3465 is one case, however, when no message is output - after "drop". In that case,
3466 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3467 passed to this function.
3468
3469 In case things go wrong while processing this function, causing an error that
3470 may re-enter this function, there is a recursion check.
3471
3472 Arguments:
3473 reason What $smtp_notquit_reason will be set to in the ACL;
3474 if NULL, the ACL is not run
3475 code The error code to return as part of the response
3476 defaultrespond The default message if there's no user_msg
3477
3478 Returns: Nothing
3479 */
3480
3481 void
3482 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3483 {
3484 int rc;
3485 uschar *user_msg = NULL;
3486 uschar *log_msg = NULL;
3487
3488 /* Check for recursive call */
3489
3490 if (fl.smtp_exit_function_called)
3491 {
3492 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3493 reason);
3494 return;
3495 }
3496 fl.smtp_exit_function_called = TRUE;
3497
3498 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3499
3500 if (acl_smtp_notquit && reason)
3501 {
3502 smtp_notquit_reason = reason;
3503 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3504 &log_msg)) == ERROR)
3505 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3506 log_msg);
3507 }
3508