Expansions: new ${authresults {mch}} for an Authentication-Results header
[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 auth_instance *authenticated_by;
135 static BOOL auth_advertised;
136 #ifdef SUPPORT_TLS
137 static BOOL tls_advertised;
138 #endif
139 static BOOL dsn_advertised;
140 static BOOL esmtp;
141 static BOOL helo_required = FALSE;
142 static BOOL helo_verify = FALSE;
143 static BOOL helo_seen;
144 static BOOL helo_accept_junk;
145 static BOOL count_nonmail;
146 static BOOL pipelining_advertised;
147 static BOOL rcpt_smtp_response_same;
148 static BOOL rcpt_in_progress;
149 static int nonmail_command_count;
150 static BOOL smtp_exit_function_called = 0;
151 #ifdef SUPPORT_I18N
152 static BOOL smtputf8_advertised;
153 #endif
154 static int synprot_error_count;
155 static int unknown_command_count;
156 static int sync_cmd_limit;
157 static int smtp_write_error = 0;
158
159 static uschar *rcpt_smtp_response;
160 static uschar *smtp_data_buffer;
161 static uschar *smtp_cmd_data;
162
163 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
164 final fields of all except AUTH are forced TRUE at the start of a new message
165 setup, to allow one of each between messages that is not counted as a nonmail
166 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
167 allow a new EHLO after starting up TLS.
168
169 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
170 counted. However, the flag is changed when AUTH is received, so that multiple
171 failing AUTHs will eventually hit the limit. After a successful AUTH, another
172 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
173 forced TRUE, to allow for the re-authentication that can happen at that point.
174
175 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
176 count of non-mail commands and possibly provoke an error.
177
178 tls_auth is a pseudo-command, never expected in input. It is activated
179 on TLS startup and looks for a tls authenticator. */
180
181 static smtp_cmd_list cmd_list[] = {
182 /* name len cmd has_arg is_mail_cmd */
183
184 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
185 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
186 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
187 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
188 #ifdef SUPPORT_TLS
189 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
190 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
191 #endif
192
193 /* If you change anything above here, also fix the definitions below. */
194
195 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
196 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
197 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
198 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
199 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
200 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
201 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
202 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
203 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
204 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
205 };
206
207 static smtp_cmd_list *cmd_list_end =
208 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
209
210 #define CMD_LIST_RSET 0
211 #define CMD_LIST_HELO 1
212 #define CMD_LIST_EHLO 2
213 #define CMD_LIST_AUTH 3
214 #define CMD_LIST_STARTTLS 4
215 #define CMD_LIST_TLS_AUTH 5
216
217 /* This list of names is used for performing the smtp_no_mail logging action.
218 It must be kept in step with the SCH_xxx enumerations. */
219
220 static uschar *smtp_names[] =
221 {
222 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
223 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
224 US"STARTTLS", US"VRFY" };
225
226 static uschar *protocols_local[] = {
227 US"local-smtp", /* HELO */
228 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
229 US"local-esmtp", /* EHLO */
230 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
231 US"local-esmtpa", /* EHLO->AUTH */
232 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
233 };
234 static uschar *protocols[] = {
235 US"smtp", /* HELO */
236 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
237 US"esmtp", /* EHLO */
238 US"esmtps", /* EHLO->STARTTLS->EHLO */
239 US"esmtpa", /* EHLO->AUTH */
240 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
241 };
242
243 #define pnormal 0
244 #define pextend 2
245 #define pcrpted 1 /* added to pextend or pnormal */
246 #define pauthed 2 /* added to pextend */
247
248 /* Sanity check and validate optional args to MAIL FROM: envelope */
249 enum {
250 ENV_MAIL_OPT_NULL,
251 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
252 #ifndef DISABLE_PRDR
253 ENV_MAIL_OPT_PRDR,
254 #endif
255 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
256 #ifdef SUPPORT_I18N
257 ENV_MAIL_OPT_UTF8,
258 #endif
259 };
260 typedef struct {
261 uschar * name; /* option requested during MAIL cmd */
262 int value; /* enum type */
263 BOOL need_value; /* TRUE requires value (name=value pair format)
264 FALSE is a singleton */
265 } env_mail_type_t;
266 static env_mail_type_t env_mail_type_list[] = {
267 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
268 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
269 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
270 #ifndef DISABLE_PRDR
271 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
272 #endif
273 { US"RET", ENV_MAIL_OPT_RET, TRUE },
274 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
275 #ifdef SUPPORT_I18N
276 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
277 #endif
278 /* keep this the last entry */
279 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
280 };
281
282 /* When reading SMTP from a remote host, we have to use our own versions of the
283 C input-reading functions, in order to be able to flush the SMTP output only
284 when about to read more data from the socket. This is the only way to get
285 optimal performance when the client is using pipelining. Flushing for every
286 command causes a separate packet and reply packet each time; saving all the
287 responses up (when pipelining) combines them into one packet and one response.
288
289 For simplicity, these functions are used for *all* SMTP input, not only when
290 receiving over a socket. However, after setting up a secure socket (SSL), input
291 is read via the OpenSSL library, and another set of functions is used instead
292 (see tls.c).
293
294 These functions are set in the receive_getc etc. variables and called with the
295 same interface as the C functions. However, since there can only ever be
296 one incoming SMTP call, we just use a single buffer and flags. There is no need
297 to implement a complicated private FILE-like structure.*/
298
299 static uschar *smtp_inbuffer;
300 static uschar *smtp_inptr;
301 static uschar *smtp_inend;
302 static int smtp_had_eof;
303 static int smtp_had_error;
304
305
306 /* forward declarations */
307 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
308 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
309 static void smtp_quit_handler(uschar **, uschar **);
310 static void smtp_rset_handler(void);
311
312 /*************************************************
313 * Recheck synchronization *
314 *************************************************/
315
316 /* Synchronization checks can never be perfect because a packet may be on its
317 way but not arrived when the check is done. Normally, the checks happen when
318 commands are read: Exim ensures that there is no more input in the input buffer.
319 In normal cases, the response to the command will be fast, and there is no
320 further check.
321
322 However, for some commands an ACL is run, and that can include delays. In those
323 cases, it is useful to do another check on the input just before sending the
324 response. This also applies at the start of a connection. This function does
325 that check by means of the select() function, as long as the facility is not
326 disabled or inappropriate. A failure of select() is ignored.
327
328 When there is unwanted input, we read it so that it appears in the log of the
329 error.
330
331 Arguments: none
332 Returns: TRUE if all is well; FALSE if there is input pending
333 */
334
335 static BOOL
336 wouldblock_reading(void)
337 {
338 int fd, rc;
339 fd_set fds;
340 struct timeval tzero;
341
342 #ifdef SUPPORT_TLS
343 if (tls_in.active >= 0)
344 return !tls_could_read();
345 #endif
346
347 if (smtp_inptr < smtp_inend)
348 return FALSE;
349
350 fd = fileno(smtp_in);
351 FD_ZERO(&fds);
352 FD_SET(fd, &fds);
353 tzero.tv_sec = 0;
354 tzero.tv_usec = 0;
355 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
356
357 if (rc <= 0) return TRUE; /* Not ready to read */
358 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
359 if (rc < 0) return TRUE; /* End of file or error */
360
361 smtp_ungetc(rc);
362 rc = smtp_inend - smtp_inptr;
363 if (rc > 150) rc = 150;
364 smtp_inptr[rc] = 0;
365 return FALSE;
366 }
367
368 static BOOL
369 check_sync(void)
370 {
371 if (!smtp_enforce_sync || sender_host_address == NULL || sender_host_notsocket)
372 return TRUE;
373
374 return wouldblock_reading();
375 }
376
377
378 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
379 a reponse with the one following. */
380
381 static BOOL
382 pipeline_response(void)
383 {
384 if ( !smtp_enforce_sync || !sender_host_address
385 || sender_host_notsocket || !pipelining_advertised)
386 return FALSE;
387
388 return !wouldblock_reading();
389 }
390
391
392
393 /*************************************************
394 * Log incomplete transactions *
395 *************************************************/
396
397 /* This function is called after a transaction has been aborted by RSET, QUIT,
398 connection drops or other errors. It logs the envelope information received
399 so far in order to preserve address verification attempts.
400
401 Argument: string to indicate what aborted the transaction
402 Returns: nothing
403 */
404
405 static void
406 incomplete_transaction_log(uschar *what)
407 {
408 if (sender_address == NULL || /* No transaction in progress */
409 !LOGGING(smtp_incomplete_transaction))
410 return;
411
412 /* Build list of recipients for logging */
413
414 if (recipients_count > 0)
415 {
416 int i;
417 raw_recipients = store_get(recipients_count * sizeof(uschar *));
418 for (i = 0; i < recipients_count; i++)
419 raw_recipients[i] = recipients_list[i].address;
420 raw_recipients_count = recipients_count;
421 }
422
423 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
424 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
425 }
426
427
428
429
430 /* Refill the buffer, and notify DKIM verification code.
431 Return false for error or EOF.
432 */
433
434 static BOOL
435 smtp_refill(unsigned lim)
436 {
437 int rc, save_errno;
438 if (!smtp_out) return FALSE;
439 fflush(smtp_out);
440 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
441
442 /* Limit amount read, so non-message data is not fed to DKIM */
443
444 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE, lim));
445 save_errno = errno;
446 alarm(0);
447 if (rc <= 0)
448 {
449 /* Must put the error text in fixed store, because this might be during
450 header reading, where it releases unused store above the header. */
451 if (rc < 0)
452 {
453 smtp_had_error = save_errno;
454 smtp_read_error = string_copy_malloc(
455 string_sprintf(" (error: %s)", strerror(save_errno)));
456 }
457 else smtp_had_eof = 1;
458 return FALSE;
459 }
460 #ifndef DISABLE_DKIM
461 dkim_exim_verify_feed(smtp_inbuffer, rc);
462 #endif
463 smtp_inend = smtp_inbuffer + rc;
464 smtp_inptr = smtp_inbuffer;
465 return TRUE;
466 }
467
468 /*************************************************
469 * SMTP version of getc() *
470 *************************************************/
471
472 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
473 it flushes the output, and refills the buffer, with a timeout. The signal
474 handler is set appropriately by the calling function. This function is not used
475 after a connection has negotiated itself into an TLS/SSL state.
476
477 Arguments: lim Maximum amount to read/buffer
478 Returns: the next character or EOF
479 */
480
481 int
482 smtp_getc(unsigned lim)
483 {
484 if (smtp_inptr >= smtp_inend)
485 if (!smtp_refill(lim))
486 return EOF;
487 return *smtp_inptr++;
488 }
489
490 uschar *
491 smtp_getbuf(unsigned * len)
492 {
493 unsigned size;
494 uschar * buf;
495
496 if (smtp_inptr >= smtp_inend)
497 if (!smtp_refill(*len))
498 { *len = 0; return NULL; }
499
500 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
501 buf = smtp_inptr;
502 smtp_inptr += size;
503 *len = size;
504 return buf;
505 }
506
507 void
508 smtp_get_cache(void)
509 {
510 #ifndef DISABLE_DKIM
511 int n = smtp_inend - smtp_inptr;
512 if (n > 0)
513 dkim_exim_verify_feed(smtp_inptr, n);
514 #endif
515 }
516
517
518 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
519 previous BDAT chunk and getting new ones when we run out. Uses the
520 underlying smtp_getc or tls_getc both for that and for getting the
521 (buffered) data byte. EOD signals (an expected) no further data.
522 ERR signals a protocol error, and EOF a closed input stream.
523
524 Called from read_bdat_smtp() in receive.c for the message body, but also
525 by the headers read loop in receive_msg(); manipulates chunking_state
526 to handle the BDAT command/response.
527 Placed here due to the correlation with the above smtp_getc(), which it wraps,
528 and also by the need to do smtp command/response handling.
529
530 Arguments: lim (ignored)
531 Returns: the next character or ERR, EOD or EOF
532 */
533
534 int
535 bdat_getc(unsigned lim)
536 {
537 uschar * user_msg = NULL;
538 uschar * log_msg;
539
540 for(;;)
541 {
542 #ifndef DISABLE_DKIM
543 BOOL dkim_save;
544 #endif
545
546 if (chunking_data_left > 0)
547 return lwr_receive_getc(chunking_data_left--);
548
549 receive_getc = lwr_receive_getc;
550 receive_getbuf = lwr_receive_getbuf;
551 receive_ungetc = lwr_receive_ungetc;
552 #ifndef DISABLE_DKIM
553 dkim_save = dkim_collect_input;
554 dkim_collect_input = FALSE;
555 #endif
556
557 /* Unless PIPELINING was offered, there should be no next command
558 until after we ack that chunk */
559
560 if (!pipelining_advertised && !check_sync())
561 {
562 unsigned n = smtp_inend - smtp_inptr;
563 if (n > 32) n = 32;
564
565 incomplete_transaction_log(US"sync failure");
566 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
567 "(next input sent too soon: pipelining was not advertised): "
568 "rejected \"%s\" %s next input=\"%s\"%s",
569 smtp_cmd_buffer, host_and_ident(TRUE),
570 string_printing(string_copyn(smtp_inptr, n)),
571 smtp_inend - smtp_inptr > n ? "..." : "");
572 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
573 US"SMTP synchronization error");
574 goto repeat_until_rset;
575 }
576
577 /* If not the last, ack the received chunk. The last response is delayed
578 until after the data ACL decides on it */
579
580 if (chunking_state == CHUNKING_LAST)
581 {
582 #ifndef DISABLE_DKIM
583 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
584 #endif
585 return EOD;
586 }
587
588 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
589 chunking_state = CHUNKING_OFFERED;
590 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
591
592 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
593 QUIT, RSET or NOOP but handling them seems obvious */
594
595 next_cmd:
596 switch(smtp_read_command(TRUE, 1))
597 {
598 default:
599 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
600 US"only BDAT permissible after non-LAST BDAT");
601
602 repeat_until_rset:
603 switch(smtp_read_command(TRUE, 1))
604 {
605 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
606 case EOF_CMD: return EOF;
607 case RSET_CMD: smtp_rset_handler(); return ERR;
608 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
609 US"only RSET accepted now") > 0)
610 return EOF;
611 goto repeat_until_rset;
612 }
613
614 case QUIT_CMD:
615 smtp_quit_handler(&user_msg, &log_msg);
616 /*FALLTHROUGH*/
617 case EOF_CMD:
618 return EOF;
619
620 case RSET_CMD:
621 smtp_rset_handler();
622 return ERR;
623
624 case NOOP_CMD:
625 HAD(SCH_NOOP);
626 smtp_printf("250 OK\r\n", FALSE);
627 goto next_cmd;
628
629 case BDAT_CMD:
630 {
631 int n;
632
633 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
634 {
635 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
636 US"missing size for BDAT command");
637 return ERR;
638 }
639 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
640 ? CHUNKING_LAST : CHUNKING_ACTIVE;
641 chunking_data_left = chunking_datasize;
642 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
643 (int)chunking_state, chunking_data_left);
644
645 if (chunking_datasize == 0)
646 if (chunking_state == CHUNKING_LAST)
647 return EOD;
648 else
649 {
650 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
651 US"zero size for BDAT command");
652 goto repeat_until_rset;
653 }
654
655 receive_getc = bdat_getc;
656 receive_getbuf = bdat_getbuf;
657 receive_ungetc = bdat_ungetc;
658 #ifndef DISABLE_DKIM
659 dkim_collect_input = dkim_save;
660 #endif
661 break; /* to top of main loop */
662 }
663 }
664 }
665 }
666
667 uschar *
668 bdat_getbuf(unsigned * len)
669 {
670 uschar * buf;
671
672 if (chunking_data_left <= 0)
673 { *len = 0; return NULL; }
674
675 if (*len > chunking_data_left) *len = chunking_data_left;
676 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
677 chunking_data_left -= *len;
678 return buf;
679 }
680
681 void
682 bdat_flush_data(void)
683 {
684 while (chunking_data_left)
685 {
686 unsigned n = chunking_data_left;
687 (void) bdat_getbuf(&n);
688 }
689
690 receive_getc = lwr_receive_getc;
691 receive_getbuf = lwr_receive_getbuf;
692 receive_ungetc = lwr_receive_ungetc;
693
694 if (chunking_state != CHUNKING_LAST)
695 {
696 chunking_state = CHUNKING_OFFERED;
697 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
698 }
699 }
700
701
702
703
704 /*************************************************
705 * SMTP version of ungetc() *
706 *************************************************/
707
708 /* Puts a character back in the input buffer. Only ever
709 called once.
710
711 Arguments:
712 ch the character
713
714 Returns: the character
715 */
716
717 int
718 smtp_ungetc(int ch)
719 {
720 *--smtp_inptr = ch;
721 return ch;
722 }
723
724
725 int
726 bdat_ungetc(int ch)
727 {
728 chunking_data_left++;
729 return lwr_receive_ungetc(ch);
730 }
731
732
733
734 /*************************************************
735 * SMTP version of feof() *
736 *************************************************/
737
738 /* Tests for a previous EOF
739
740 Arguments: none
741 Returns: non-zero if the eof flag is set
742 */
743
744 int
745 smtp_feof(void)
746 {
747 return smtp_had_eof;
748 }
749
750
751
752
753 /*************************************************
754 * SMTP version of ferror() *
755 *************************************************/
756
757 /* Tests for a previous read error, and returns with errno
758 restored to what it was when the error was detected.
759
760 Arguments: none
761 Returns: non-zero if the error flag is set
762 */
763
764 int
765 smtp_ferror(void)
766 {
767 errno = smtp_had_error;
768 return smtp_had_error;
769 }
770
771
772
773 /*************************************************
774 * Test for characters in the SMTP buffer *
775 *************************************************/
776
777 /* Used at the end of a message
778
779 Arguments: none
780 Returns: TRUE/FALSE
781 */
782
783 BOOL
784 smtp_buffered(void)
785 {
786 return smtp_inptr < smtp_inend;
787 }
788
789
790
791 /*************************************************
792 * Write formatted string to SMTP channel *
793 *************************************************/
794
795 /* This is a separate function so that we don't have to repeat everything for
796 TLS support or debugging. It is global so that the daemon and the
797 authentication functions can use it. It does not return any error indication,
798 because major problems such as dropped connections won't show up till an output
799 flush for non-TLS connections. The smtp_fflush() function is available for
800 checking that: for convenience, TLS output errors are remembered here so that
801 they are also picked up later by smtp_fflush().
802
803 Arguments:
804 format format string
805 more further data expected
806 ... optional arguments
807
808 Returns: nothing
809 */
810
811 void
812 smtp_printf(const char *format, BOOL more, ...)
813 {
814 va_list ap;
815
816 va_start(ap, more);
817 smtp_vprintf(format, more, ap);
818 va_end(ap);
819 }
820
821 /* This is split off so that verify.c:respond_printf() can, in effect, call
822 smtp_printf(), bearing in mind that in C a vararg function can't directly
823 call another vararg function, only a function which accepts a va_list. */
824
825 void
826 smtp_vprintf(const char *format, BOOL more, va_list ap)
827 {
828 BOOL yield;
829
830 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
831
832 DEBUG(D_receive)
833 {
834 void *reset_point = store_get(0);
835 uschar *msg_copy, *cr, *end;
836 msg_copy = string_copy(big_buffer);
837 end = msg_copy + Ustrlen(msg_copy);
838 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
839 memmove(cr, cr + 1, (end--) - cr);
840 debug_printf("SMTP>> %s", msg_copy);
841 store_reset(reset_point);
842 }
843
844 if (!yield)
845 {
846 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
847 smtp_closedown(US"Unexpected error");
848 exim_exit(EXIT_FAILURE, NULL);
849 }
850
851 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
852 have had the same. Note: this code is also present in smtp_respond(). It would
853 be tidier to have it only in one place, but when it was added, it was easier to
854 do it that way, so as not to have to mess with the code for the RCPT command,
855 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
856
857 if (rcpt_in_progress)
858 {
859 if (rcpt_smtp_response == NULL)
860 rcpt_smtp_response = string_copy(big_buffer);
861 else if (rcpt_smtp_response_same &&
862 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
863 rcpt_smtp_response_same = FALSE;
864 rcpt_in_progress = FALSE;
865 }
866
867 /* Now write the string */
868
869 #ifdef SUPPORT_TLS
870 if (tls_in.active >= 0)
871 {
872 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer), more) < 0)
873 smtp_write_error = -1;
874 }
875 else
876 #endif
877
878 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
879 }
880
881
882
883 /*************************************************
884 * Flush SMTP out and check for error *
885 *************************************************/
886
887 /* This function isn't currently used within Exim (it detects errors when it
888 tries to read the next SMTP input), but is available for use in local_scan().
889 For non-TLS connections, it flushes the output and checks for errors. For
890 TLS-connections, it checks for a previously-detected TLS write error.
891
892 Arguments: none
893 Returns: 0 for no error; -1 after an error
894 */
895
896 int
897 smtp_fflush(void)
898 {
899 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
900 return smtp_write_error;
901 }
902
903
904
905 /*************************************************
906 * SMTP command read timeout *
907 *************************************************/
908
909 /* Signal handler for timing out incoming SMTP commands. This attempts to
910 finish off tidily.
911
912 Argument: signal number (SIGALRM)
913 Returns: nothing
914 */
915
916 static void
917 command_timeout_handler(int sig)
918 {
919 sig = sig; /* Keep picky compilers happy */
920 log_write(L_lost_incoming_connection,
921 LOG_MAIN, "SMTP command timeout on%s connection from %s",
922 (tls_in.active >= 0)? " TLS" : "",
923 host_and_ident(FALSE));
924 if (smtp_batched_input)
925 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
926 smtp_notquit_exit(US"command-timeout", US"421",
927 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
928 exim_exit(EXIT_FAILURE, US"receiving");
929 }
930
931
932
933 /*************************************************
934 * SIGTERM received *
935 *************************************************/
936
937 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
938
939 Argument: signal number (SIGTERM)
940 Returns: nothing
941 */
942
943 static void
944 command_sigterm_handler(int sig)
945 {
946 sig = sig; /* Keep picky compilers happy */
947 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
948 if (smtp_batched_input)
949 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
950 smtp_notquit_exit(US"signal-exit", US"421",
951 US"%s: Service not available - closing connection", smtp_active_hostname);
952 exim_exit(EXIT_FAILURE, US"receiving");
953 }
954
955
956
957
958 #ifdef SUPPORT_PROXY
959 /*************************************************
960 * Restore socket timeout to previous value *
961 *************************************************/
962 /* If the previous value was successfully retrieved, restore
963 it before returning control to the non-proxy routines
964
965 Arguments: fd - File descriptor for input
966 get_ok - Successfully retrieved previous values
967 tvtmp - Time struct with previous values
968 vslen - Length of time struct
969 Returns: none
970 */
971 static void
972 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
973 {
974 if (get_ok == 0)
975 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
976 }
977
978 /*************************************************
979 * Check if host is required proxy host *
980 *************************************************/
981 /* The function determines if inbound host will be a regular smtp host
982 or if it is configured that it must use Proxy Protocol. A local
983 connection cannot.
984
985 Arguments: none
986 Returns: bool
987 */
988
989 static BOOL
990 check_proxy_protocol_host()
991 {
992 int rc;
993
994 if ( sender_host_address
995 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
996 sender_host_address, NULL)) == OK)
997 {
998 DEBUG(D_receive)
999 debug_printf("Detected proxy protocol configured host\n");
1000 proxy_session = TRUE;
1001 }
1002 return proxy_session;
1003 }
1004
1005
1006 /*************************************************
1007 * Read data until newline or end of buffer *
1008 *************************************************/
1009 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1010 read an entire buffer and assume there will be nothing past a proxy protocol
1011 header. Our approach normally is to use stdio, but again that relies upon
1012 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1013 reading _nothing_ before client TLS handshake. So we don't want to use the
1014 usual buffering reads which may read enough to block TLS starting.
1015
1016 So unfortunately we're down to "read one byte at a time, with a syscall each,
1017 and expect a little overhead", for all proxy-opened connections which are v1,
1018 just to handle the TLS-on-connect case. Since SSL functions wrap the
1019 underlying fd, we can't assume that we can feed them any already-read content.
1020
1021 We need to know where to read to, the max capacity, and we'll read until we
1022 get a CR and one more character. Let the caller scream if it's CR+!LF.
1023
1024 Return the amount read.
1025 */
1026
1027 static int
1028 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1029 {
1030 uschar *to = base + already;
1031 uschar *cr;
1032 int have = 0;
1033 int ret;
1034 int last = 0;
1035
1036 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1037 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1038
1039 cr = memchr(base, '\r', already);
1040 if (cr != NULL)
1041 {
1042 if ((cr - base) < already - 1)
1043 {
1044 /* \r and presumed \n already within what we have; probably not
1045 actually proxy protocol, but abort cleanly. */
1046 return 0;
1047 }
1048 /* \r is last character read, just need one more. */
1049 last = 1;
1050 }
1051
1052 while (capacity > 0)
1053 {
1054 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1055 if (ret == -1)
1056 return -1;
1057 have++;
1058 if (last)
1059 return have;
1060 if (*to == '\r')
1061 last = 1;
1062 capacity--;
1063 to++;
1064 }
1065
1066 /* reached end without having room for a final newline, abort */
1067 errno = EOVERFLOW;
1068 return -1;
1069 }
1070
1071 /*************************************************
1072 * Setup host for proxy protocol *
1073 *************************************************/
1074 /* The function configures the connection based on a header from the
1075 inbound host to use Proxy Protocol. The specification is very exact
1076 so exit with an error if do not find the exact required pieces. This
1077 includes an incorrect number of spaces separating args.
1078
1079 Arguments: none
1080 Returns: Boolean success
1081 */
1082
1083 static void
1084 setup_proxy_protocol_host()
1085 {
1086 union {
1087 struct {
1088 uschar line[108];
1089 } v1;
1090 struct {
1091 uschar sig[12];
1092 uint8_t ver_cmd;
1093 uint8_t fam;
1094 uint16_t len;
1095 union {
1096 struct { /* TCP/UDP over IPv4, len = 12 */
1097 uint32_t src_addr;
1098 uint32_t dst_addr;
1099 uint16_t src_port;
1100 uint16_t dst_port;
1101 } ip4;
1102 struct { /* TCP/UDP over IPv6, len = 36 */
1103 uint8_t src_addr[16];
1104 uint8_t dst_addr[16];
1105 uint16_t src_port;
1106 uint16_t dst_port;
1107 } ip6;
1108 struct { /* AF_UNIX sockets, len = 216 */
1109 uschar src_addr[108];
1110 uschar dst_addr[108];
1111 } unx;
1112 } addr;
1113 } v2;
1114 } hdr;
1115
1116 /* Temp variables used in PPv2 address:port parsing */
1117 uint16_t tmpport;
1118 char tmpip[INET_ADDRSTRLEN];
1119 struct sockaddr_in tmpaddr;
1120 char tmpip6[INET6_ADDRSTRLEN];
1121 struct sockaddr_in6 tmpaddr6;
1122
1123 /* We can't read "all data until end" because while SMTP is
1124 server-speaks-first, the TLS handshake is client-speaks-first, so for
1125 TLS-on-connect ports the proxy protocol header will usually be immediately
1126 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1127 reinject data for reading by those. So instead we first read "enough to be
1128 safely read within the header, and figure out how much more to read".
1129 For v1 we will later read to the end-of-line, for v2 we will read based upon
1130 the stated length.
1131
1132 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1133 data is needed total. For v1, where the line looks like:
1134 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1135
1136 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1137 We seem to support that. So, if we read 14 octets then we can tell if we're
1138 v2 or v1. If we're v1, we can continue reading as normal.
1139
1140 If we're v2, we can't slurp up the entire header. We need the length in the
1141 15th & 16th octets, then to read everything after that.
1142
1143 So to safely handle v1 and v2, with client-sent-first supported correctly,
1144 we have to do a minimum of 3 read calls, not 1. Eww.
1145 */
1146
1147 #define PROXY_INITIAL_READ 14
1148 #define PROXY_V2_HEADER_SIZE 16
1149 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1150 # error Code bug in sizes of data to read for proxy usage
1151 #endif
1152
1153 int get_ok = 0;
1154 int size, ret;
1155 int fd = fileno(smtp_in);
1156 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1157 uschar * iptype; /* To display debug info */
1158 struct timeval tv;
1159 struct timeval tvtmp;
1160 socklen_t vslen = sizeof(struct timeval);
1161 BOOL yield = FALSE;
1162
1163 /* Save current socket timeout values */
1164 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1165
1166 /* Proxy Protocol host must send header within a short time
1167 (default 3 seconds) or it's considered invalid */
1168 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1169 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1170 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1171 goto bad;
1172
1173 do
1174 {
1175 /* The inbound host was declared to be a Proxy Protocol host, so
1176 don't do a PEEK into the data, actually slurp up enough to be
1177 "safe". Can't take it all because TLS-on-connect clients follow
1178 immediately with TLS handshake. */
1179 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1180 }
1181 while (ret == -1 && errno == EINTR);
1182
1183 if (ret == -1)
1184 goto proxyfail;
1185
1186 /* For v2, handle reading the length, and then the rest. */
1187 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1188 {
1189 int retmore;
1190 uint8_t ver;
1191
1192 /* First get the length fields. */
1193 do
1194 {
1195 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1196 } while (retmore == -1 && errno == EINTR);
1197 if (retmore == -1)
1198 goto proxyfail;
1199 ret += retmore;
1200
1201 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1202
1203 /* May 2014: haproxy combined the version and command into one byte to
1204 allow two full bytes for the length field in order to proxy SSL
1205 connections. SSL Proxy is not supported in this version of Exim, but
1206 must still separate values here. */
1207
1208 if (ver != 0x02)
1209 {
1210 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1211 goto proxyfail;
1212 }
1213
1214 /* The v2 header will always be 16 bytes per the spec. */
1215 size = 16 + ntohs(hdr.v2.len);
1216 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1217 size, (int)sizeof(hdr));
1218
1219 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1220 amount that we need. Double-check that the size is not unreasonable, then
1221 get the rest. */
1222 if (size > sizeof(hdr))
1223 {
1224 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1225 goto proxyfail;
1226 }
1227
1228 do
1229 {
1230 do
1231 {
1232 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1233 } while (retmore == -1 && errno == EINTR);
1234 if (retmore == -1)
1235 goto proxyfail;
1236 ret += retmore;
1237 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1238 } while (ret < size);
1239
1240 } /* end scope for getting rest of data for v2 */
1241
1242 /* At this point: if PROXYv2, we've read the exact size required for all data;
1243 if PROXYv1 then we've read "less than required for any valid line" and should
1244 read the rest". */
1245
1246 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1247 {
1248 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1249
1250 switch (cmd)
1251 {
1252 case 0x01: /* PROXY command */
1253 switch (hdr.v2.fam)
1254 {
1255 case 0x11: /* TCPv4 address type */
1256 iptype = US"IPv4";
1257 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1258 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1259 if (!string_is_ip_address(US tmpip, NULL))
1260 {
1261 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1262 goto proxyfail;
1263 }
1264 proxy_local_address = sender_host_address;
1265 sender_host_address = string_copy(US tmpip);
1266 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1267 proxy_local_port = sender_host_port;
1268 sender_host_port = tmpport;
1269 /* Save dest ip/port */
1270 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1271 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1272 if (!string_is_ip_address(US tmpip, NULL))
1273 {
1274 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1275 goto proxyfail;
1276 }
1277 proxy_external_address = string_copy(US tmpip);
1278 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1279 proxy_external_port = tmpport;
1280 goto done;
1281 case 0x21: /* TCPv6 address type */
1282 iptype = US"IPv6";
1283 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1284 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1285 if (!string_is_ip_address(US tmpip6, NULL))
1286 {
1287 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1288 goto proxyfail;
1289 }
1290 proxy_local_address = sender_host_address;
1291 sender_host_address = string_copy(US tmpip6);
1292 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1293 proxy_local_port = sender_host_port;
1294 sender_host_port = tmpport;
1295 /* Save dest ip/port */
1296 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1297 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1298 if (!string_is_ip_address(US tmpip6, NULL))
1299 {
1300 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1301 goto proxyfail;
1302 }
1303 proxy_external_address = string_copy(US tmpip6);
1304 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1305 proxy_external_port = tmpport;
1306 goto done;
1307 default:
1308 DEBUG(D_receive)
1309 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1310 hdr.v2.fam);
1311 goto proxyfail;
1312 }
1313 /* Unsupported protocol, keep local connection address */
1314 break;
1315 case 0x00: /* LOCAL command */
1316 /* Keep local connection address for LOCAL */
1317 iptype = US"local";
1318 break;
1319 default:
1320 DEBUG(D_receive)
1321 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1322 goto proxyfail;
1323 }
1324 }
1325 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1326 {
1327 uschar *p;
1328 uschar *end;
1329 uschar *sp; /* Utility variables follow */
1330 int tmp_port;
1331 int r2;
1332 char *endc;
1333
1334 /* get the rest of the line */
1335 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1336 if (r2 == -1)
1337 goto proxyfail;
1338 ret += r2;
1339
1340 p = string_copy(hdr.v1.line);
1341 end = memchr(p, '\r', ret - 1);
1342
1343 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1344 {
1345 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1346 goto proxyfail;
1347 }
1348 *end = '\0'; /* Terminate the string */
1349 size = end + 2 - p; /* Skip header + CRLF */
1350 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1351 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1352 /* Step through the string looking for the required fields. Ensure
1353 strict adherence to required formatting, exit for any error. */
1354 p += 5;
1355 if (!isspace(*(p++)))
1356 {
1357 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1358 goto proxyfail;
1359 }
1360 if (!Ustrncmp(p, CCS"TCP4", 4))
1361 iptype = US"IPv4";
1362 else if (!Ustrncmp(p,CCS"TCP6", 4))
1363 iptype = US"IPv6";
1364 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1365 {
1366 iptype = US"Unknown";
1367 goto done;
1368 }
1369 else
1370 {
1371 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1372 goto proxyfail;
1373 }
1374
1375 p += Ustrlen(iptype);
1376 if (!isspace(*(p++)))
1377 {
1378 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1379 goto proxyfail;
1380 }
1381 /* Find the end of the arg */
1382 if ((sp = Ustrchr(p, ' ')) == NULL)
1383 {
1384 DEBUG(D_receive)
1385 debug_printf("Did not find proxied src %s\n", iptype);
1386 goto proxyfail;
1387 }
1388 *sp = '\0';
1389 if(!string_is_ip_address(p, NULL))
1390 {
1391 DEBUG(D_receive)
1392 debug_printf("Proxied src arg is not an %s address\n", iptype);
1393 goto proxyfail;
1394 }
1395 proxy_local_address = sender_host_address;
1396 sender_host_address = p;
1397 p = sp + 1;
1398 if ((sp = Ustrchr(p, ' ')) == NULL)
1399 {
1400 DEBUG(D_receive)
1401 debug_printf("Did not find proxy dest %s\n", iptype);
1402 goto proxyfail;
1403 }
1404 *sp = '\0';
1405 if(!string_is_ip_address(p, NULL))
1406 {
1407 DEBUG(D_receive)
1408 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1409 goto proxyfail;
1410 }
1411 proxy_external_address = p;
1412 p = sp + 1;
1413 if ((sp = Ustrchr(p, ' ')) == NULL)
1414 {
1415 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1416 goto proxyfail;
1417 }
1418 *sp = '\0';
1419 tmp_port = strtol(CCS p, &endc, 10);
1420 if (*endc || tmp_port == 0)
1421 {
1422 DEBUG(D_receive)
1423 debug_printf("Proxied src port '%s' not an integer\n", p);
1424 goto proxyfail;
1425 }
1426 proxy_local_port = sender_host_port;
1427 sender_host_port = tmp_port;
1428 p = sp + 1;
1429 if ((sp = Ustrchr(p, '\0')) == NULL)
1430 {
1431 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1432 goto proxyfail;
1433 }
1434 tmp_port = strtol(CCS p, &endc, 10);
1435 if (*endc || tmp_port == 0)
1436 {
1437 DEBUG(D_receive)
1438 debug_printf("Proxy dest port '%s' not an integer\n", p);
1439 goto proxyfail;
1440 }
1441 proxy_external_port = tmp_port;
1442 /* Already checked for /r /n above. Good V1 header received. */
1443 }
1444 else
1445 {
1446 /* Wrong protocol */
1447 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1448 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1449 goto proxyfail;
1450 }
1451
1452 done:
1453 DEBUG(D_receive)
1454 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1455 yield = proxy_session;
1456
1457 /* Don't flush any potential buffer contents. Any input on proxyfail
1458 should cause a synchronization failure */
1459
1460 proxyfail:
1461 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1462
1463 bad:
1464 if (yield)
1465 {
1466 sender_host_name = NULL;
1467 (void) host_name_lookup();
1468 host_build_sender_fullhost();
1469 }
1470 else
1471 {
1472 proxy_session_failed = TRUE;
1473 DEBUG(D_receive)
1474 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1475 }
1476
1477 return;
1478 }
1479 #endif
1480
1481 /*************************************************
1482 * Read one command line *
1483 *************************************************/
1484
1485 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1486 There are sites that don't do this, and in any case internal SMTP probably
1487 should check only for LF. Consequently, we check here for LF only. The line
1488 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1489 an unknown command. The command is read into the global smtp_cmd_buffer so that
1490 it is available via $smtp_command.
1491
1492 The character reading routine sets up a timeout for each block actually read
1493 from the input (which may contain more than one command). We set up a special
1494 signal handler that closes down the session on a timeout. Control does not
1495 return when it runs.
1496
1497 Arguments:
1498 check_sync if TRUE, check synchronization rules if global option is TRUE
1499 buffer_lim maximum to buffer in lower layer
1500
1501 Returns: a code identifying the command (enumerated above)
1502 */
1503
1504 static int
1505 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1506 {
1507 int c;
1508 int ptr = 0;
1509 smtp_cmd_list *p;
1510 BOOL hadnull = FALSE;
1511
1512 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1513
1514 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1515 {
1516 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1517 {
1518 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1519 return OTHER_CMD;
1520 }
1521 if (c == 0)
1522 {
1523 hadnull = TRUE;
1524 c = '?';
1525 }
1526 smtp_cmd_buffer[ptr++] = c;
1527 }
1528
1529 receive_linecount++; /* For BSMTP errors */
1530 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1531
1532 /* If hit end of file, return pseudo EOF command. Whether we have a
1533 part-line already read doesn't matter, since this is an error state. */
1534
1535 if (c == EOF) return EOF_CMD;
1536
1537 /* Remove any CR and white space at the end of the line, and terminate the
1538 string. */
1539
1540 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1541 smtp_cmd_buffer[ptr] = 0;
1542
1543 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1544
1545 /* NULLs are not allowed in SMTP commands */
1546
1547 if (hadnull) return BADCHAR_CMD;
1548
1549 /* Scan command list and return identity, having set the data pointer
1550 to the start of the actual data characters. Check for SMTP synchronization
1551 if required. */
1552
1553 for (p = cmd_list; p < cmd_list_end; p++)
1554 {
1555 #ifdef SUPPORT_PROXY
1556 /* Only allow QUIT command if Proxy Protocol parsing failed */
1557 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1558 continue;
1559 #endif
1560 if ( p->len
1561 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1562 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1563 || smtp_cmd_buffer[p->len] == 0
1564 || smtp_cmd_buffer[p->len] == ' '
1565 ) )
1566 {
1567 if (smtp_inptr < smtp_inend && /* Outstanding input */
1568 p->cmd < sync_cmd_limit && /* Command should sync */
1569 check_sync && /* Local flag set */
1570 smtp_enforce_sync && /* Global flag set */
1571 sender_host_address != NULL && /* Not local input */
1572 !sender_host_notsocket) /* Really is a socket */
1573 return BADSYN_CMD;
1574
1575 /* The variables $smtp_command and $smtp_command_argument point into the
1576 unmodified input buffer. A copy of the latter is taken for actual
1577 processing, so that it can be chopped up into separate parts if necessary,
1578 for example, when processing a MAIL command options such as SIZE that can
1579 follow the sender address. */
1580
1581 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1582 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1583 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1584 smtp_cmd_data = smtp_data_buffer;
1585
1586 /* Count non-mail commands from those hosts that are controlled in this
1587 way. The default is all hosts. We don't waste effort checking the list
1588 until we get a non-mail command, but then cache the result to save checking
1589 again. If there's a DEFER while checking the host, assume it's in the list.
1590
1591 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1592 start of each incoming message by fiddling with the value in the table. */
1593
1594 if (!p->is_mail_cmd)
1595 {
1596 if (count_nonmail == TRUE_UNSET) count_nonmail =
1597 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1598 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1599 return TOO_MANY_NONMAIL_CMD;
1600 }
1601
1602 /* If there is data for a command that does not expect it, generate the
1603 error here. */
1604
1605 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1606 }
1607 }
1608
1609 #ifdef SUPPORT_PROXY
1610 /* Only allow QUIT command if Proxy Protocol parsing failed */
1611 if (proxy_session && proxy_session_failed)
1612 return PROXY_FAIL_IGNORE_CMD;
1613 #endif
1614
1615 /* Enforce synchronization for unknown commands */
1616
1617 if (smtp_inptr < smtp_inend && /* Outstanding input */
1618 check_sync && /* Local flag set */
1619 smtp_enforce_sync && /* Global flag set */
1620 sender_host_address != NULL && /* Not local input */
1621 !sender_host_notsocket) /* Really is a socket */
1622 return BADSYN_CMD;
1623
1624 return OTHER_CMD;
1625 }
1626
1627
1628
1629 /*************************************************
1630 * Forced closedown of call *
1631 *************************************************/
1632
1633 /* This function is called from log.c when Exim is dying because of a serious
1634 disaster, and also from some other places. If an incoming non-batched SMTP
1635 channel is open, it swallows the rest of the incoming message if in the DATA
1636 phase, sends the reply string, and gives an error to all subsequent commands
1637 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1638 smtp_in.
1639
1640 Arguments:
1641 message SMTP reply string to send, excluding the code
1642
1643 Returns: nothing
1644 */
1645
1646 void
1647 smtp_closedown(uschar *message)
1648 {
1649 if (!smtp_in || smtp_batched_input) return;
1650 receive_swallow_smtp();
1651 smtp_printf("421 %s\r\n", FALSE, message);
1652
1653 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1654 {
1655 case EOF_CMD:
1656 return;
1657
1658 case QUIT_CMD:
1659 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1660 mac_smtp_fflush();
1661 return;
1662
1663 case RSET_CMD:
1664 smtp_printf("250 Reset OK\r\n", FALSE);
1665 break;
1666
1667 default:
1668 smtp_printf("421 %s\r\n", FALSE, message);
1669 break;
1670 }
1671 }
1672
1673
1674
1675
1676 /*************************************************
1677 * Set up connection info for logging *
1678 *************************************************/
1679
1680 /* This function is called when logging information about an SMTP connection.
1681 It sets up appropriate source information, depending on the type of connection.
1682 If sender_fullhost is NULL, we are at a very early stage of the connection;
1683 just use the IP address.
1684
1685 Argument: none
1686 Returns: a string describing the connection
1687 */
1688
1689 uschar *
1690 smtp_get_connection_info(void)
1691 {
1692 const uschar * hostname = sender_fullhost
1693 ? sender_fullhost : sender_host_address;
1694
1695 if (host_checking)
1696 return string_sprintf("SMTP connection from %s", hostname);
1697
1698 if (sender_host_unknown || sender_host_notsocket)
1699 return string_sprintf("SMTP connection from %s", sender_ident);
1700
1701 if (is_inetd)
1702 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1703
1704 if (LOGGING(incoming_interface) && interface_address != NULL)
1705 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1706 interface_address, interface_port);
1707
1708 return string_sprintf("SMTP connection from %s", hostname);
1709 }
1710
1711
1712
1713 #ifdef SUPPORT_TLS
1714 /* Append TLS-related information to a log line
1715
1716 Arguments:
1717 g String under construction: allocated string to extend, or NULL
1718
1719 Returns: Allocated string or NULL
1720 */
1721 static gstring *
1722 s_tlslog(gstring * g)
1723 {
1724 if (LOGGING(tls_cipher) && tls_in.cipher)
1725 g = string_append(g, 2, US" X=", tls_in.cipher);
1726 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1727 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1728 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1729 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1730 if (LOGGING(tls_sni) && tls_in.sni)
1731 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1732 return g;
1733 }
1734 #endif
1735
1736 /*************************************************
1737 * Log lack of MAIL if so configured *
1738 *************************************************/
1739
1740 /* This function is called when an SMTP session ends. If the log selector
1741 smtp_no_mail is set, write a log line giving some details of what has happened
1742 in the SMTP session.
1743
1744 Arguments: none
1745 Returns: nothing
1746 */
1747
1748 void
1749 smtp_log_no_mail(void)
1750 {
1751 int i;
1752 uschar * sep, * s;
1753 gstring * g = NULL;
1754
1755 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1756 return;
1757
1758 if (sender_host_authenticated)
1759 {
1760 g = string_append(g, 2, US" A=", sender_host_authenticated);
1761 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1762 }
1763
1764 #ifdef SUPPORT_TLS
1765 g = s_tlslog(g);
1766 #endif
1767
1768 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1769
1770 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1771 if (smtp_connection_had[i] != SCH_NONE)
1772 {
1773 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1774 sep = US",";
1775 }
1776
1777 for (i = 0; i < smtp_ch_index; i++)
1778 {
1779 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1780 sep = US",";
1781 }
1782
1783 if (!(s = string_from_gstring(g))) s = US"";
1784
1785 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1786 tcp_in_fastopen ? US"TFO " : US"",
1787 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1788 }
1789
1790
1791 /* Return list of recent smtp commands */
1792
1793 uschar *
1794 smtp_cmd_hist(void)
1795 {
1796 int i;
1797 gstring * list = NULL;
1798 uschar * s;
1799
1800 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1801 if (smtp_connection_had[i] != SCH_NONE)
1802 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1803
1804 for (i = 0; i < smtp_ch_index; i++)
1805 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1806
1807 s = string_from_gstring(list);
1808 return s ? s : US"";
1809 }
1810
1811
1812
1813
1814 /*************************************************
1815 * Check HELO line and set sender_helo_name *
1816 *************************************************/
1817
1818 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1819 the domain name of the sending host, or an ip literal in square brackets. The
1820 argument is placed in sender_helo_name, which is in malloc store, because it
1821 must persist over multiple incoming messages. If helo_accept_junk is set, this
1822 host is permitted to send any old junk (needed for some broken hosts).
1823 Otherwise, helo_allow_chars can be used for rogue characters in general
1824 (typically people want to let in underscores).
1825
1826 Argument:
1827 s the data portion of the line (already past any white space)
1828
1829 Returns: TRUE or FALSE
1830 */
1831
1832 static BOOL
1833 check_helo(uschar *s)
1834 {
1835 uschar *start = s;
1836 uschar *end = s + Ustrlen(s);
1837 BOOL yield = helo_accept_junk;
1838
1839 /* Discard any previous helo name */
1840
1841 if (sender_helo_name)
1842 {
1843 store_free(sender_helo_name);
1844 sender_helo_name = NULL;
1845 }
1846
1847 /* Skip tests if junk is permitted. */
1848
1849 if (!yield)
1850
1851 /* Allow the new standard form for IPv6 address literals, namely,
1852 [IPv6:....], and because someone is bound to use it, allow an equivalent
1853 IPv4 form. Allow plain addresses as well. */
1854
1855 if (*s == '[')
1856 {
1857 if (end[-1] == ']')
1858 {
1859 end[-1] = 0;
1860 if (strncmpic(s, US"[IPv6:", 6) == 0)
1861 yield = (string_is_ip_address(s+6, NULL) == 6);
1862 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1863 yield = (string_is_ip_address(s+6, NULL) == 4);
1864 else
1865 yield = (string_is_ip_address(s+1, NULL) != 0);
1866 end[-1] = ']';
1867 }
1868 }
1869
1870 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1871 that have been configured (usually underscore - sigh). */
1872
1873 else if (*s)
1874 for (yield = TRUE; *s; s++)
1875 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1876 Ustrchr(helo_allow_chars, *s) == NULL)
1877 {
1878 yield = FALSE;
1879 break;
1880 }
1881
1882 /* Save argument if OK */
1883
1884 if (yield) sender_helo_name = string_copy_malloc(start);
1885 return yield;
1886 }
1887
1888
1889
1890
1891
1892 /*************************************************
1893 * Extract SMTP command option *
1894 *************************************************/
1895
1896 /* This function picks the next option setting off the end of smtp_cmd_data. It
1897 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1898 things that can appear there.
1899
1900 Arguments:
1901 name point this at the name
1902 value point this at the data string
1903
1904 Returns: TRUE if found an option
1905 */
1906
1907 static BOOL
1908 extract_option(uschar **name, uschar **value)
1909 {
1910 uschar *n;
1911 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1912 while (isspace(*v)) v--;
1913 v[1] = 0;
1914 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1915 {
1916 /* Take care to not stop at a space embedded in a quoted local-part */
1917
1918 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1919 v--;
1920 }
1921
1922 n = v;
1923 if (*v == '=')
1924 {
1925 while(isalpha(n[-1])) n--;
1926 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1927 if (!isspace(n[-1])) return FALSE;
1928 n[-1] = 0;
1929 }
1930 else
1931 {
1932 n++;
1933 if (v == smtp_cmd_data) return FALSE;
1934 }
1935 *v++ = 0;
1936 *name = n;
1937 *value = v;
1938 return TRUE;
1939 }
1940
1941
1942
1943
1944
1945 /*************************************************
1946 * Reset for new message *
1947 *************************************************/
1948
1949 /* This function is called whenever the SMTP session is reset from
1950 within either of the setup functions.
1951
1952 Argument: the stacking pool storage reset point
1953 Returns: nothing
1954 */
1955
1956 static void
1957 smtp_reset(void *reset_point)
1958 {
1959 recipients_list = NULL;
1960 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1961 raw_recipients_count = recipients_count = recipients_list_max = 0;
1962 message_linecount = 0;
1963 message_size = -1;
1964 acl_added_headers = NULL;
1965 acl_removed_headers = NULL;
1966 queue_only_policy = FALSE;
1967 rcpt_smtp_response = NULL;
1968 rcpt_smtp_response_same = TRUE;
1969 rcpt_in_progress = FALSE;
1970 deliver_freeze = FALSE; /* Can be set by ACL */
1971 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1972 fake_response = OK; /* Can be set by ACL */
1973 #ifdef WITH_CONTENT_SCAN
1974 no_mbox_unspool = FALSE; /* Can be set by ACL */
1975 #endif
1976 submission_mode = FALSE; /* Can be set by ACL */
1977 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1978 active_local_from_check = local_from_check; /* Can be set by ACL */
1979 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1980 sending_ip_address = NULL;
1981 return_path = sender_address = NULL;
1982 sender_data = NULL; /* Can be set by ACL */
1983 deliver_localpart_orig = NULL;
1984 deliver_domain_orig = NULL;
1985 callout_address = NULL;
1986 submission_name = NULL; /* Can be set by ACL */
1987 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1988 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1989 sender_verified_list = NULL; /* No senders verified */
1990 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1991 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1992
1993 authenticated_sender = NULL;
1994 #ifdef EXPERIMENTAL_BRIGHTMAIL
1995 bmi_run = 0;
1996 bmi_verdicts = NULL;
1997 #endif
1998 dnslist_domain = dnslist_matched = NULL;
1999 #ifndef DISABLE_DKIM
2000 dkim_signers = NULL;
2001 dkim_disable_verify = FALSE;
2002 dkim_collect_input = FALSE;
2003 #endif
2004 dsn_ret = 0;
2005 dsn_envid = NULL;
2006 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2007 #ifndef DISABLE_PRDR
2008 prdr_requested = FALSE;
2009 #endif
2010 #ifdef SUPPORT_SPF
2011 spf_header_comment = NULL;
2012 spf_received = NULL;
2013 spf_result = NULL;
2014 spf_smtp_comment = NULL;
2015 #endif
2016 #ifdef SUPPORT_I18N
2017 message_smtputf8 = FALSE;
2018 #endif
2019 body_linecount = body_zerocount = 0;
2020
2021 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2022 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2023 /* Note that ratelimiters_conn persists across resets. */
2024
2025 /* Reset message ACL variables */
2026
2027 acl_var_m = NULL;
2028
2029 /* The message body variables use malloc store. They may be set if this is
2030 not the first message in an SMTP session and the previous message caused them
2031 to be referenced in an ACL. */
2032
2033 if (message_body)
2034 {
2035 store_free(message_body);
2036 message_body = NULL;
2037 }
2038
2039 if (message_body_end)
2040 {
2041 store_free(message_body_end);
2042 message_body_end = NULL;
2043 }
2044
2045 /* Warning log messages are also saved in malloc store. They are saved to avoid
2046 repetition in the same message, but it seems right to repeat them for different
2047 messages. */
2048
2049 while (acl_warn_logged)
2050 {
2051 string_item *this = acl_warn_logged;
2052 acl_warn_logged = acl_warn_logged->next;
2053 store_free(this);
2054 }
2055 store_reset(reset_point);
2056 }
2057
2058
2059
2060
2061
2062 /*************************************************
2063 * Initialize for incoming batched SMTP message *
2064 *************************************************/
2065
2066 /* This function is called from smtp_setup_msg() in the case when
2067 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2068 of messages in one file with SMTP commands between them. All errors must be
2069 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2070 relevant. After an error on a sender, or an invalid recipient, the remainder
2071 of the message is skipped. The value of received_protocol is already set.
2072
2073 Argument: none
2074 Returns: > 0 message successfully started (reached DATA)
2075 = 0 QUIT read or end of file reached
2076 < 0 should not occur
2077 */
2078
2079 static int
2080 smtp_setup_batch_msg(void)
2081 {
2082 int done = 0;
2083 void *reset_point = store_get(0);
2084
2085 /* Save the line count at the start of each transaction - single commands
2086 like HELO and RSET count as whole transactions. */
2087
2088 bsmtp_transaction_linecount = receive_linecount;
2089
2090 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2091
2092 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2093 smtp_reset(reset_point); /* Reset for start of message */
2094
2095 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2096 value. The values are 2 larger than the required yield of the function. */
2097
2098 while (done <= 0)
2099 {
2100 uschar *errmess;
2101 uschar *recipient = NULL;
2102 int start, end, sender_domain, recipient_domain;
2103
2104 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2105 {
2106 /* The HELO/EHLO commands set sender_address_helo if they have
2107 valid data; otherwise they are ignored, except that they do
2108 a reset of the state. */
2109
2110 case HELO_CMD:
2111 case EHLO_CMD:
2112
2113 check_helo(smtp_cmd_data);
2114 /* Fall through */
2115
2116 case RSET_CMD:
2117 cancel_cutthrough_connection(TRUE, US"RSET received");
2118 smtp_reset(reset_point);
2119 bsmtp_transaction_linecount = receive_linecount;
2120 break;
2121
2122
2123 /* The MAIL FROM command requires an address as an operand. All we
2124 do here is to parse it for syntactic correctness. The form "<>" is
2125 a special case which converts into an empty string. The start/end
2126 pointers in the original are not used further for this address, as
2127 it is the canonical extracted address which is all that is kept. */
2128
2129 case MAIL_CMD:
2130 smtp_mailcmd_count++; /* Count for no-mail log */
2131 if (sender_address != NULL)
2132 /* The function moan_smtp_batch() does not return. */
2133 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2134
2135 if (smtp_cmd_data[0] == 0)
2136 /* The function moan_smtp_batch() does not return. */
2137 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2138
2139 /* Reset to start of message */
2140
2141 cancel_cutthrough_connection(TRUE, US"MAIL received");
2142 smtp_reset(reset_point);
2143
2144 /* Apply SMTP rewrite */
2145
2146 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2147 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2148 US"", global_rewrite_rules) : smtp_cmd_data;
2149
2150 /* Extract the address; the TRUE flag allows <> as valid */
2151
2152 raw_sender =
2153 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2154 TRUE);
2155
2156 if (!raw_sender)
2157 /* The function moan_smtp_batch() does not return. */
2158 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2159
2160 sender_address = string_copy(raw_sender);
2161
2162 /* Qualify unqualified sender addresses if permitted to do so. */
2163
2164 if ( !sender_domain
2165 && sender_address[0] != 0 && sender_address[0] != '@')
2166 if (allow_unqualified_sender)
2167 {
2168 sender_address = rewrite_address_qualify(sender_address, FALSE);
2169 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2170 "and rewritten\n", raw_sender);
2171 }
2172 /* The function moan_smtp_batch() does not return. */
2173 else
2174 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2175 "a domain");
2176 break;
2177
2178
2179 /* The RCPT TO command requires an address as an operand. All we do
2180 here is to parse it for syntactic correctness. There may be any number
2181 of RCPT TO commands, specifying multiple senders. We build them all into
2182 a data structure that is in argc/argv format. The start/end values
2183 given by parse_extract_address are not used, as we keep only the
2184 extracted address. */
2185
2186 case RCPT_CMD:
2187 if (!sender_address)
2188 /* The function moan_smtp_batch() does not return. */
2189 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2190
2191 if (smtp_cmd_data[0] == 0)
2192 /* The function moan_smtp_batch() does not return. */
2193 moan_smtp_batch(smtp_cmd_buffer,
2194 "501 RCPT TO must have an address operand");
2195
2196 /* Check maximum number allowed */
2197
2198 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2199 /* The function moan_smtp_batch() does not return. */
2200 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2201 recipients_max_reject? "552": "452");
2202
2203 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2204 recipient address */
2205
2206 recipient = rewrite_existflags & rewrite_smtp
2207 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2208 global_rewrite_rules)
2209 : smtp_cmd_data;
2210
2211 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2212 &recipient_domain, FALSE);
2213
2214 if (!recipient)
2215 /* The function moan_smtp_batch() does not return. */
2216 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2217
2218 /* If the recipient address is unqualified, qualify it if permitted. Then
2219 add it to the list of recipients. */
2220
2221 if (!recipient_domain)
2222 if (allow_unqualified_recipient)
2223 {
2224 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2225 recipient);
2226 recipient = rewrite_address_qualify(recipient, TRUE);
2227 }
2228 /* The function moan_smtp_batch() does not return. */
2229 else
2230 moan_smtp_batch(smtp_cmd_buffer,
2231 "501 recipient address must contain a domain");
2232
2233 receive_add_recipient(recipient, -1);
2234 break;
2235
2236
2237 /* The DATA command is legal only if it follows successful MAIL FROM
2238 and RCPT TO commands. This function is complete when a valid DATA
2239 command is encountered. */
2240
2241 case DATA_CMD:
2242 if (!sender_address || recipients_count <= 0)
2243 /* The function moan_smtp_batch() does not return. */
2244 if (!sender_address)
2245 moan_smtp_batch(smtp_cmd_buffer,
2246 "503 MAIL FROM:<sender> command must precede DATA");
2247 else
2248 moan_smtp_batch(smtp_cmd_buffer,
2249 "503 RCPT TO:<recipient> must precede DATA");
2250 else
2251 {
2252 done = 3; /* DATA successfully achieved */
2253 message_ended = END_NOTENDED; /* Indicate in middle of message */
2254 }
2255 break;
2256
2257
2258 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2259
2260 case VRFY_CMD:
2261 case EXPN_CMD:
2262 case HELP_CMD:
2263 case NOOP_CMD:
2264 case ETRN_CMD:
2265 bsmtp_transaction_linecount = receive_linecount;
2266 break;
2267
2268
2269 case EOF_CMD:
2270 case QUIT_CMD:
2271 done = 2;
2272 break;
2273
2274
2275 case BADARG_CMD:
2276 /* The function moan_smtp_batch() does not return. */
2277 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2278 break;
2279
2280
2281 case BADCHAR_CMD:
2282 /* The function moan_smtp_batch() does not return. */
2283 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2284 break;
2285
2286
2287 default:
2288 /* The function moan_smtp_batch() does not return. */
2289 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2290 break;
2291 }
2292 }
2293
2294 return done - 2; /* Convert yield values */
2295 }
2296
2297
2298
2299
2300 static BOOL
2301 smtp_log_tls_fail(uschar * errstr)
2302 {
2303 uschar * conn_info = smtp_get_connection_info();
2304
2305 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2306 /* I'd like to get separated H= here, but too hard for now */
2307
2308 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2309 return FALSE;
2310 }
2311
2312
2313
2314
2315 #ifdef TCP_FASTOPEN
2316 static void
2317 tfo_in_check(void)
2318 {
2319 # ifdef TCP_INFO
2320 struct tcp_info tinfo;
2321 socklen_t len = sizeof(tinfo);
2322
2323 if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
2324 && tinfo.tcpi_state == TCP_SYN_RECV
2325 )
2326 {
2327 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
2328 tcp_in_fastopen = TRUE;
2329 }
2330 # endif
2331 }
2332 #endif
2333
2334
2335 /*************************************************
2336 * Start an SMTP session *
2337 *************************************************/
2338
2339 /* This function is called at the start of an SMTP session. Thereafter,
2340 smtp_setup_msg() is called to initiate each separate message. This
2341 function does host-specific testing, and outputs the banner line.
2342
2343 Arguments: none
2344 Returns: FALSE if the session can not continue; something has
2345 gone wrong, or the connection to the host is blocked
2346 */
2347
2348 BOOL
2349 smtp_start_session(void)
2350 {
2351 int esclen;
2352 uschar *user_msg, *log_msg;
2353 uschar *code, *esc;
2354 uschar *p, *s;
2355 gstring * ss;
2356
2357 gettimeofday(&smtp_connection_start, NULL);
2358 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2359 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2360 smtp_ch_index = 0;
2361
2362 /* Default values for certain variables */
2363
2364 helo_seen = esmtp = helo_accept_junk = FALSE;
2365 smtp_mailcmd_count = 0;
2366 count_nonmail = TRUE_UNSET;
2367 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2368 smtp_delay_mail = smtp_rlm_base;
2369 auth_advertised = FALSE;
2370 pipelining_advertised = FALSE;
2371 pipelining_enable = TRUE;
2372 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2373 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2374
2375 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2376 authentication settings from -oMaa to remain in force. */
2377
2378 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2379 authenticated_by = NULL;
2380
2381 #ifdef SUPPORT_TLS
2382 tls_in.cipher = tls_in.peerdn = NULL;
2383 tls_in.ourcert = tls_in.peercert = NULL;
2384 tls_in.sni = NULL;
2385 tls_in.ocsp = OCSP_NOT_REQ;
2386 tls_advertised = FALSE;
2387 #endif
2388 dsn_advertised = FALSE;
2389 #ifdef SUPPORT_I18N
2390 smtputf8_advertised = FALSE;
2391 #endif
2392
2393 /* Reset ACL connection variables */
2394
2395 acl_var_c = NULL;
2396
2397 /* Allow for trailing 0 in the command and data buffers. */
2398
2399 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2400 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2401 "malloc() failed for SMTP command buffer");
2402
2403 smtp_cmd_buffer[0] = 0;
2404 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2405
2406 /* For batched input, the protocol setting can be overridden from the
2407 command line by a trusted caller. */
2408
2409 if (smtp_batched_input)
2410 {
2411 if (!received_protocol) received_protocol = US"local-bsmtp";
2412 }
2413
2414 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2415 reset later if any of EHLO/AUTH/STARTTLS are received. */
2416
2417 else
2418 received_protocol =
2419 (sender_host_address ? protocols : protocols_local) [pnormal];
2420
2421 /* Set up the buffer for inputting using direct read() calls, and arrange to
2422 call the local functions instead of the standard C ones. */
2423
2424 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2425 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2426
2427 receive_getc = smtp_getc;
2428 receive_getbuf = smtp_getbuf;
2429 receive_get_cache = smtp_get_cache;
2430 receive_ungetc = smtp_ungetc;
2431 receive_feof = smtp_feof;
2432 receive_ferror = smtp_ferror;
2433 receive_smtp_buffered = smtp_buffered;
2434 smtp_inptr = smtp_inend = smtp_inbuffer;
2435 smtp_had_eof = smtp_had_error = 0;
2436
2437 /* Set up the message size limit; this may be host-specific */
2438
2439 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2440 if (expand_string_message)
2441 {
2442 if (thismessage_size_limit == -1)
2443 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2444 "%s", expand_string_message);
2445 else
2446 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2447 "%s", expand_string_message);
2448 smtp_closedown(US"Temporary local problem - please try later");
2449 return FALSE;
2450 }
2451
2452 /* When a message is input locally via the -bs or -bS options, sender_host_
2453 unknown is set unless -oMa was used to force an IP address, in which case it
2454 is checked like a real remote connection. When -bs is used from inetd, this
2455 flag is not set, causing the sending host to be checked. The code that deals
2456 with IP source routing (if configured) is never required for -bs or -bS and
2457 the flag sender_host_notsocket is used to suppress it.
2458
2459 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2460 reserve for certain hosts and/or networks. */
2461
2462 if (!sender_host_unknown)
2463 {
2464 int rc;
2465 BOOL reserved_host = FALSE;
2466
2467 /* Look up IP options (source routing info) on the socket if this is not an
2468 -oMa "host", and if any are found, log them and drop the connection.
2469
2470 Linux (and others now, see below) is different to everyone else, so there
2471 has to be some conditional compilation here. Versions of Linux before 2.1.15
2472 used a structure whose name was "options". Somebody finally realized that
2473 this name was silly, and it got changed to "ip_options". I use the
2474 newer name here, but there is a fudge in the script that sets up os.h
2475 to define a macro in older Linux systems.
2476
2477 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2478 glibc 2, which has chosen ip_opts for the structure name. This is now
2479 really a glibc thing rather than a Linux thing, so the condition name
2480 has been changed to reflect this. It is relevant also to GNU/Hurd.
2481
2482 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2483 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2484 a special macro defined in the os.h file.
2485
2486 Some DGUX versions on older hardware appear not to support IP options at
2487 all, so there is now a general macro which can be set to cut out this
2488 support altogether.
2489
2490 How to do this properly in IPv6 is not yet known. */
2491
2492 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2493
2494 #ifdef GLIBC_IP_OPTIONS
2495 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2496 #define OPTSTYLE 1
2497 #else
2498 #define OPTSTYLE 2
2499 #endif
2500 #elif defined DARWIN_IP_OPTIONS
2501 #define OPTSTYLE 2
2502 #else
2503 #define OPTSTYLE 3
2504 #endif
2505
2506 if (!host_checking && !sender_host_notsocket)
2507 {
2508 #if OPTSTYLE == 1
2509 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2510 struct ip_options *ipopt = store_get(optlen);
2511 #elif OPTSTYLE == 2
2512 struct ip_opts ipoptblock;
2513 struct ip_opts *ipopt = &ipoptblock;
2514 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2515 #else
2516 struct ipoption ipoptblock;
2517 struct ipoption *ipopt = &ipoptblock;
2518 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2519 #endif
2520
2521 /* Occasional genuine failures of getsockopt() have been seen - for
2522 example, "reset by peer". Therefore, just log and give up on this
2523 call, unless the error is ENOPROTOOPT. This error is given by systems
2524 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2525 of writing. So for that error, carry on - we just can't do an IP options
2526 check. */
2527
2528 DEBUG(D_receive) debug_printf("checking for IP options\n");
2529
2530 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2531 &optlen) < 0)
2532 {
2533 if (errno != ENOPROTOOPT)
2534 {
2535 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2536 host_and_ident(FALSE), strerror(errno));
2537 smtp_printf("451 SMTP service not available\r\n", FALSE);
2538 return FALSE;
2539 }
2540 }
2541
2542 /* Deal with any IP options that are set. On the systems I have looked at,
2543 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2544 more logging data than will fit in big_buffer. Nevertheless, after somebody
2545 questioned this code, I've added in some paranoid checking. */
2546
2547 else if (optlen > 0)
2548 {
2549 uschar *p = big_buffer;
2550 uschar *pend = big_buffer + big_buffer_size;
2551 uschar *opt, *adptr;
2552 int optcount;
2553 struct in_addr addr;
2554
2555 #if OPTSTYLE == 1
2556 uschar *optstart = US (ipopt->__data);
2557 #elif OPTSTYLE == 2
2558 uschar *optstart = US (ipopt->ip_opts);
2559 #else
2560 uschar *optstart = US (ipopt->ipopt_list);
2561 #endif
2562
2563 DEBUG(D_receive) debug_printf("IP options exist\n");
2564
2565 Ustrcpy(p, "IP options on incoming call:");
2566 p += Ustrlen(p);
2567
2568 for (opt = optstart; opt != NULL &&
2569 opt < US (ipopt) + optlen;)
2570 {
2571 switch (*opt)
2572 {
2573 case IPOPT_EOL:
2574 opt = NULL;
2575 break;
2576
2577 case IPOPT_NOP:
2578 opt++;
2579 break;
2580
2581 case IPOPT_SSRR:
2582 case IPOPT_LSRR:
2583 if (!string_format(p, pend-p, " %s [@%s",
2584 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2585 #if OPTSTYLE == 1
2586 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2587 #elif OPTSTYLE == 2
2588 inet_ntoa(ipopt->ip_dst)))
2589 #else
2590 inet_ntoa(ipopt->ipopt_dst)))
2591 #endif
2592 {
2593 opt = NULL;
2594 break;
2595 }
2596
2597 p += Ustrlen(p);
2598 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2599 adptr = opt + 3;
2600 while (optcount-- > 0)
2601 {
2602 memcpy(&addr, adptr, sizeof(addr));
2603 if (!string_format(p, pend - p - 1, "%s%s",
2604 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2605 {
2606 opt = NULL;
2607 break;
2608 }
2609 p += Ustrlen(p);
2610 adptr += sizeof(struct in_addr);
2611 }
2612 *p++ = ']';
2613 opt += opt[1];
2614 break;
2615
2616 default:
2617 {
2618 int i;
2619 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2620 Ustrcat(p, "[ ");
2621 p += 2;
2622 for (i = 0; i < opt[1]; i++)
2623 p += sprintf(CS p, "%2.2x ", opt[i]);
2624 *p++ = ']';
2625 }
2626 opt += opt[1];
2627 break;
2628 }
2629 }
2630
2631 *p = 0;
2632 log_write(0, LOG_MAIN, "%s", big_buffer);
2633
2634 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2635
2636 log_write(0, LOG_MAIN|LOG_REJECT,
2637 "connection from %s refused (IP options)", host_and_ident(FALSE));
2638
2639 smtp_printf("554 SMTP service not available\r\n", FALSE);
2640 return FALSE;
2641 }
2642
2643 /* Length of options = 0 => there are no options */
2644
2645 else DEBUG(D_receive) debug_printf("no IP options found\n");
2646 }
2647 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2648
2649 /* Set keep-alive in socket options. The option is on by default. This
2650 setting is an attempt to get rid of some hanging connections that stick in
2651 read() when the remote end (usually a dialup) goes away. */
2652
2653 if (smtp_accept_keepalive && !sender_host_notsocket)
2654 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2655
2656 /* If the current host matches host_lookup, set the name by doing a
2657 reverse lookup. On failure, sender_host_name will be NULL and
2658 host_lookup_failed will be TRUE. This may or may not be serious - optional
2659 checks later. */
2660
2661 if (verify_check_host(&host_lookup) == OK)
2662 {
2663 (void)host_name_lookup();
2664 host_build_sender_fullhost();
2665 }
2666
2667 /* Delay this until we have the full name, if it is looked up. */
2668
2669 set_process_info("handling incoming connection from %s",
2670 host_and_ident(FALSE));
2671
2672 /* Expand smtp_receive_timeout, if needed */
2673
2674 if (smtp_receive_timeout_s)
2675 {
2676 uschar * exp;
2677 if ( !(exp = expand_string(smtp_receive_timeout_s))
2678 || !(*exp)
2679 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2680 )
2681 log_write(0, LOG_MAIN|LOG_PANIC,
2682 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2683 }
2684
2685 /* Test for explicit connection rejection */
2686
2687 if (verify_check_host(&host_reject_connection) == OK)
2688 {
2689 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2690 "from %s (host_reject_connection)", host_and_ident(FALSE));
2691 smtp_printf("554 SMTP service not available\r\n", FALSE);
2692 return FALSE;
2693 }
2694
2695 /* Test with TCP Wrappers if so configured. There is a problem in that
2696 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2697 such as disks dying. In these cases, it is desirable to reject with a 4xx
2698 error instead of a 5xx error. There isn't a "right" way to detect such
2699 problems. The following kludge is used: errno is zeroed before calling
2700 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2701 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2702 not exist). */
2703
2704 #ifdef USE_TCP_WRAPPERS
2705 errno = 0;
2706 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2707 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2708 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2709 expand_string_message);
2710
2711 if (!hosts_ctl(tcp_wrappers_name,
2712 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2713 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2714 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2715 {
2716 if (errno == 0 || errno == ENOENT)
2717 {
2718 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2719 log_write(L_connection_reject,
2720 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2721 "(tcp wrappers)", host_and_ident(FALSE));
2722 smtp_printf("554 SMTP service not available\r\n", FALSE);
2723 }
2724 else
2725 {
2726 int save_errno = errno;
2727 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2728 "errno value %d\n", save_errno);
2729 log_write(L_connection_reject,
2730 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2731 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2732 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2733 }
2734 return FALSE;
2735 }
2736 #endif
2737
2738 /* Check for reserved slots. The value of smtp_accept_count has already been
2739 incremented to include this process. */
2740
2741 if (smtp_accept_max > 0 &&
2742 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2743 {
2744 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2745 {
2746 log_write(L_connection_reject,
2747 LOG_MAIN, "temporarily refused connection from %s: not in "
2748 "reserve list: connected=%d max=%d reserve=%d%s",
2749 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2750 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2751 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2752 "please try again later\r\n", FALSE, smtp_active_hostname);
2753 return FALSE;
2754 }
2755 reserved_host = TRUE;
2756 }
2757
2758 /* If a load level above which only messages from reserved hosts are
2759 accepted is set, check the load. For incoming calls via the daemon, the
2760 check is done in the superior process if there are no reserved hosts, to
2761 save a fork. In all cases, the load average will already be available
2762 in a global variable at this point. */
2763
2764 if (smtp_load_reserve >= 0 &&
2765 load_average > smtp_load_reserve &&
2766 !reserved_host &&
2767 verify_check_host(&smtp_reserve_hosts) != OK)
2768 {
2769 log_write(L_connection_reject,
2770 LOG_MAIN, "temporarily refused connection from %s: not in "
2771 "reserve list and load average = %.2f", host_and_ident(FALSE),
2772 (double)load_average/1000.0);
2773 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2774 smtp_active_hostname);
2775 return FALSE;
2776 }
2777
2778 /* Determine whether unqualified senders or recipients are permitted
2779 for this host. Unfortunately, we have to do this every time, in order to
2780 set the flags so that they can be inspected when considering qualifying
2781 addresses in the headers. For a site that permits no qualification, this
2782 won't take long, however. */
2783
2784 allow_unqualified_sender =
2785 verify_check_host(&sender_unqualified_hosts) == OK;
2786
2787 allow_unqualified_recipient =
2788 verify_check_host(&recipient_unqualified_hosts) == OK;
2789
2790 /* Determine whether HELO/EHLO is required for this host. The requirement
2791 can be hard or soft. */
2792
2793 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2794 if (!helo_required)
2795 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2796
2797 /* Determine whether this hosts is permitted to send syntactic junk
2798 after a HELO or EHLO command. */
2799
2800 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2801 }
2802
2803 /* For batch SMTP input we are now done. */
2804
2805 if (smtp_batched_input) return TRUE;
2806
2807 /* If valid Proxy Protocol source is connecting, set up session.
2808 * Failure will not allow any SMTP function other than QUIT. */
2809
2810 #ifdef SUPPORT_PROXY
2811 proxy_session = FALSE;
2812 proxy_session_failed = FALSE;
2813 if (check_proxy_protocol_host())
2814 setup_proxy_protocol_host();
2815 #endif
2816
2817 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2818 smtps port for use with older style SSL MTAs. */
2819
2820 #ifdef SUPPORT_TLS
2821 if (tls_in.on_connect)
2822 {
2823 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2824 return smtp_log_tls_fail(user_msg);
2825 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2826 }
2827 #endif
2828
2829 /* Run the connect ACL if it exists */
2830
2831 user_msg = NULL;
2832 if (acl_smtp_connect)
2833 {
2834 int rc;
2835 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2836 &log_msg)) != OK)
2837 {
2838 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2839 return FALSE;
2840 }
2841 }
2842
2843 /* Output the initial message for a two-way SMTP connection. It may contain
2844 newlines, which then cause a multi-line response to be given. */
2845
2846 code = US"220"; /* Default status code */
2847 esc = US""; /* Default extended status code */
2848 esclen = 0; /* Length of esc */
2849
2850 if (!user_msg)
2851 {
2852 if (!(s = expand_string(smtp_banner)))
2853 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2854 "failed: %s", smtp_banner, expand_string_message);
2855 }
2856 else
2857 {
2858 int codelen = 3;
2859 s = user_msg;
2860 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2861 if (codelen > 4)
2862 {
2863 esc = code + 4;
2864 esclen = codelen - 4;
2865 }
2866 }
2867
2868 /* Remove any terminating newlines; might as well remove trailing space too */
2869
2870 p = s + Ustrlen(s);
2871 while (p > s && isspace(p[-1])) p--;
2872 *p = 0;
2873
2874 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2875 is all contained in a single IP packet. The original code wrote out the
2876 greeting using several calls to fprint/fputc, and on busy servers this could
2877 cause it to be split over more than one packet - which caused CC:Mail to fall
2878 over when it got the second part of the greeting after sending its first
2879 command. Sigh. To try to avoid this, build the complete greeting message
2880 first, and output it in one fell swoop. This gives a better chance of it
2881 ending up as a single packet. */
2882
2883 ss = string_get(256);
2884
2885 p = s;
2886 do /* At least once, in case we have an empty string */
2887 {
2888 int len;
2889 uschar *linebreak = Ustrchr(p, '\n');
2890 ss = string_catn(ss, code, 3);
2891 if (!linebreak)
2892 {
2893 len = Ustrlen(p);
2894 ss = string_catn(ss, US" ", 1);
2895 }
2896 else
2897 {
2898 len = linebreak - p;
2899 ss = string_catn(ss, US"-", 1);
2900 }
2901 ss = string_catn(ss, esc, esclen);
2902 ss = string_catn(ss, p, len);
2903 ss = string_catn(ss, US"\r\n", 2);
2904 p += len;
2905 if (linebreak) p++;
2906 }
2907 while (*p);
2908
2909 /* Before we write the banner, check that there is no input pending, unless
2910 this synchronisation check is disabled. */
2911
2912 if (!check_sync())
2913 {
2914 unsigned n = smtp_inend - smtp_inptr;
2915 if (n > 32) n = 32;
2916
2917 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2918 "synchronization error (input sent without waiting for greeting): "
2919 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2920 string_printing(string_copyn(smtp_inptr, n)));
2921 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2922 return FALSE;
2923 }
2924
2925 /* Now output the banner */
2926
2927 smtp_printf("%s", FALSE, string_from_gstring(ss));
2928
2929 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2930 handshake arrived. If so we must have managed a TFO. */
2931
2932 #ifdef TCP_FASTOPEN
2933 tfo_in_check();
2934 #endif
2935
2936 return TRUE;
2937 }
2938
2939
2940
2941
2942
2943 /*************************************************
2944 * Handle SMTP syntax and protocol errors *
2945 *************************************************/
2946
2947 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2948 to do so. Then transmit the error response. The return value depends on the
2949 number of syntax and protocol errors in this SMTP session.
2950
2951 Arguments:
2952 type error type, given as a log flag bit
2953 code response code; <= 0 means don't send a response
2954 data data to reflect in the response (can be NULL)
2955 errmess the error message
2956
2957 Returns: -1 limit of syntax/protocol errors NOT exceeded
2958 +1 limit of syntax/protocol errors IS exceeded
2959
2960 These values fit in with the values of the "done" variable in the main
2961 processing loop in smtp_setup_msg(). */
2962
2963 static int
2964 synprot_error(int type, int code, uschar *data, uschar *errmess)
2965 {
2966 int yield = -1;
2967
2968 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2969 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2970 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2971
2972 if (++synprot_error_count > smtp_max_synprot_errors)
2973 {
2974 yield = 1;
2975 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2976 "syntax or protocol errors (last command was \"%s\")",
2977 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2978 }
2979
2980 if (code > 0)
2981 {
2982 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
2983 data ? data : US"", data ? US": " : US"", errmess);
2984 if (yield == 1)
2985 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
2986 }
2987
2988 return yield;
2989 }
2990
2991
2992
2993
2994 /*************************************************
2995 * Send SMTP response, possibly multiline *
2996 *************************************************/
2997
2998 /* There are, it seems, broken clients out there that cannot handle multiline
2999 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3000 output nothing for non-final calls, and only the first line for anything else.
3001
3002 Arguments:
3003 code SMTP code, may involve extended status codes
3004 codelen length of smtp code; if > 4 there's an ESC
3005 final FALSE if the last line isn't the final line
3006 msg message text, possibly containing newlines
3007
3008 Returns: nothing
3009 */
3010
3011 void
3012 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3013 {
3014 int esclen = 0;
3015 uschar *esc = US"";
3016
3017 if (!final && no_multiline_responses) return;
3018
3019 if (codelen > 4)
3020 {
3021 esc = code + 4;
3022 esclen = codelen - 4;
3023 }
3024
3025 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3026 have had the same. Note: this code is also present in smtp_printf(). It would
3027 be tidier to have it only in one place, but when it was added, it was easier to
3028 do it that way, so as not to have to mess with the code for the RCPT command,
3029 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3030
3031 if (rcpt_in_progress)
3032 {
3033 if (rcpt_smtp_response == NULL)
3034 rcpt_smtp_response = string_copy(msg);
3035 else if (rcpt_smtp_response_same &&
3036 Ustrcmp(rcpt_smtp_response, msg) != 0)
3037 rcpt_smtp_response_same = FALSE;
3038 rcpt_in_progress = FALSE;
3039 }
3040
3041 /* Now output the message, splitting it up into multiple lines if necessary.
3042 We only handle pipelining these responses as far as nonfinal/final groups,
3043 not the whole MAIL/RCPT/DATA response set. */
3044
3045 for (;;)
3046 {
3047 uschar *nl = Ustrchr(msg, '\n');
3048 if (nl == NULL)
3049 {
3050 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3051 return;
3052 }
3053 else if (nl[1] == 0 || no_multiline_responses)
3054 {
3055 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3056 (int)(nl - msg), msg);
3057 return;
3058 }
3059 else
3060 {
3061 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3062 msg = nl + 1;
3063 while (isspace(*msg)) msg++;
3064 }
3065 }
3066 }
3067
3068
3069
3070
3071 /*************************************************
3072 * Parse user SMTP message *
3073 *************************************************/
3074
3075 /* This function allows for user messages overriding the response code details
3076 by providing a suitable response code string at the start of the message
3077 user_msg. Check the message for starting with a response code and optionally an
3078 extended status code. If found, check that the first digit is valid, and if so,
3079 change the code pointer and length to use the replacement. An invalid code
3080 causes a panic log; in this case, if the log messages is the same as the user
3081 message, we must also adjust the value of the log message to show the code that
3082 is actually going to be used (the original one).
3083
3084 This function is global because it is called from receive.c as well as within
3085 this module.
3086
3087 Note that the code length returned includes the terminating whitespace
3088 character, which is always included in the regex match.
3089
3090 Arguments:
3091 code SMTP code, may involve extended status codes
3092 codelen length of smtp code; if > 4 there's an ESC
3093 msg message text
3094 log_msg optional log message, to be adjusted with the new SMTP code
3095 check_valid if true, verify the response code
3096
3097 Returns: nothing
3098 */
3099
3100 void
3101 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3102 BOOL check_valid)
3103 {
3104 int n;
3105 int ovector[3];
3106
3107 if (!msg || !*msg) return;
3108
3109 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3110 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3111
3112 if (check_valid && (*msg)[0] != (*code)[0])
3113 {
3114 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3115 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3116 if (log_msg != NULL && *log_msg == *msg)
3117 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3118 }
3119 else
3120 {
3121 *code = *msg;
3122 *codelen = ovector[1]; /* Includes final space */
3123 }
3124 *msg += ovector[1]; /* Chop the code off the message */
3125 return;
3126 }
3127
3128
3129
3130
3131 /*************************************************
3132 * Handle an ACL failure *
3133 *************************************************/
3134
3135 /* This function is called when acl_check() fails. As well as calls from within
3136 this module, it is called from receive.c for an ACL after DATA. It sorts out
3137 logging the incident, and sends the error response. A message containing
3138 newlines is turned into a multiline SMTP response, but for logging, only the
3139 first line is used.
3140
3141 There's a table of default permanent failure response codes to use in
3142 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3143 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3144 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3145 state, because there are broken clients that try VRFY before RCPT. A 5xx
3146 response should be given only when the address is positively known to be
3147 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3148 no explicit code, but if there is one we let it know best.
3149 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3150
3151 From Exim 4.63, it is possible to override the response code details by
3152 providing a suitable response code string at the start of the message provided
3153 in user_msg. The code's first digit is checked for validity.
3154
3155 Arguments:
3156 where where the ACL was called from
3157 rc the failure code
3158 user_msg a message that can be included in an SMTP response
3159 log_msg a message for logging
3160
3161 Returns: 0 in most cases
3162 2 if the failure code was FAIL_DROP, in which case the
3163 SMTP connection should be dropped (this value fits with the
3164 "done" variable in smtp_setup_msg() below)
3165 */
3166
3167 int
3168 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3169 {
3170 BOOL drop = rc == FAIL_DROP;
3171 int codelen = 3;
3172 uschar *smtp_code;
3173 uschar *lognl;
3174 uschar *sender_info = US"";
3175 uschar *what =
3176 #ifdef WITH_CONTENT_SCAN
3177 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3178 #endif
3179 where == ACL_WHERE_PREDATA ? US"DATA" :
3180 where == ACL_WHERE_DATA ? US"after DATA" :
3181 #ifndef DISABLE_PRDR
3182 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3183 #endif
3184 smtp_cmd_data ?
3185 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3186 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3187
3188 if (drop) rc = FAIL;
3189
3190 /* Set the default SMTP code, and allow a user message to change it. */
3191
3192 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3193 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3194 where != ACL_WHERE_VRFY);
3195
3196 /* We used to have sender_address here; however, there was a bug that was not
3197 updating sender_address after a rewrite during a verify. When this bug was
3198 fixed, sender_address at this point became the rewritten address. I'm not sure
3199 this is what should be logged, so I've changed to logging the unrewritten
3200 address to retain backward compatibility. */
3201
3202 #ifndef WITH_CONTENT_SCAN
3203 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3204 #else
3205 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3206 #endif
3207 {
3208 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3209 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3210 sender_host_authenticated ? US" A=" : US"",
3211 sender_host_authenticated ? sender_host_authenticated : US"",
3212 sender_host_authenticated && authenticated_id ? US":" : US"",
3213 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3214 );
3215 }
3216
3217 /* If there's been a sender verification failure with a specific message, and
3218 we have not sent a response about it yet, do so now, as a preliminary line for
3219 failures, but not defers. However, always log it for defer, and log it for fail
3220 unless the sender_verify_fail log selector has been turned off. */
3221
3222 if (sender_verified_failed &&
3223 !testflag(sender_verified_failed, af_sverify_told))
3224 {
3225 BOOL save_rcpt_in_progress = rcpt_in_progress;
3226 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3227
3228 setflag(sender_verified_failed, af_sverify_told);
3229
3230 if (rc != FAIL || LOGGING(sender_verify_fail))
3231 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3232 host_and_ident(TRUE),
3233 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3234 sender_verified_failed->address,
3235 (sender_verified_failed->message == NULL)? US"" :
3236 string_sprintf(": %s", sender_verified_failed->message));
3237
3238 if (rc == FAIL && sender_verified_failed->user_message)
3239 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3240 testflag(sender_verified_failed, af_verify_pmfail)?
3241 "Postmaster verification failed while checking <%s>\n%s\n"
3242 "Several RFCs state that you are required to have a postmaster\n"
3243 "mailbox for each mail domain. This host does not accept mail\n"
3244 "from domains whose servers reject the postmaster address."
3245 :
3246 testflag(sender_verified_failed, af_verify_nsfail)?
3247 "Callback setup failed while verifying <%s>\n%s\n"
3248 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3249 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3250 "RFC requirements, and stops you from receiving standard bounce\n"
3251 "messages. This host does not accept mail from domains whose servers\n"
3252 "refuse bounces."
3253 :
3254 "Verification failed for <%s>\n%s",
3255 sender_verified_failed->address,
3256 sender_verified_failed->user_message));
3257
3258 rcpt_in_progress = save_rcpt_in_progress;
3259 }
3260
3261 /* Sort out text for logging */
3262
3263 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3264 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3265
3266 /* Send permanent failure response to the command, but the code used isn't
3267 always a 5xx one - see comments at the start of this function. If the original
3268 rc was FAIL_DROP we drop the connection and yield 2. */
3269
3270 if (rc == FAIL)
3271 smtp_respond(smtp_code, codelen, TRUE,
3272 user_msg ? user_msg : US"Administrative prohibition");
3273
3274 /* Send temporary failure response to the command. Don't give any details,
3275 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3276 verb, and for a header verify when smtp_return_error_details is set.
3277
3278 This conditional logic is all somewhat of a mess because of the odd
3279 interactions between temp_details and return_error_details. One day it should
3280 be re-implemented in a tidier fashion. */
3281
3282 else
3283 if (acl_temp_details && user_msg)
3284 {
3285 if ( smtp_return_error_details
3286 && sender_verified_failed
3287 && sender_verified_failed->message
3288 )
3289 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3290
3291 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3292 }
3293 else
3294 smtp_respond(smtp_code, codelen, TRUE,
3295 US"Temporary local problem - please try later");
3296
3297 /* Log the incident to the logs that are specified by log_reject_target
3298 (default main, reject). This can be empty to suppress logging of rejections. If
3299 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3300 is closing if required and return 2. */
3301
3302 if (log_reject_target != 0)
3303 {
3304 #ifdef SUPPORT_TLS
3305 gstring * g = s_tlslog(NULL);
3306 uschar * tls = string_from_gstring(g);
3307 if (!tls) tls = US"";
3308 #else
3309 uschar * tls = US"";
3310 #endif
3311 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3312 log_reject_target, "%s%s%s %s%srejected %s%s",
3313 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3314 host_and_ident(TRUE),
3315 tls,
3316 sender_info,
3317 rc == FAIL ? US"" : US"temporarily ",
3318 what, log_msg);
3319 }
3320
3321 if (!drop) return 0;
3322
3323 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3324 smtp_get_connection_info());
3325
3326 /* Run the not-quit ACL, but without any custom messages. This should not be a
3327 problem, because we get here only if some other ACL has issued "drop", and
3328 in that case, *its* custom messages will have been used above. */
3329
3330 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3331 return 2;
3332 }
3333
3334
3335
3336
3337 /*************************************************
3338 * Handle SMTP exit when QUIT is not given *
3339 *************************************************/
3340
3341 /* This function provides a logging/statistics hook for when an SMTP connection
3342 is dropped on the floor or the other end goes away. It's a global function
3343 because it's called from receive.c as well as this module. As well as running
3344 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3345 response, either with a custom message from the ACL, or using a default. There
3346 is one case, however, when no message is output - after "drop". In that case,
3347 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3348 passed to this function.
3349
3350 In case things go wrong while processing this function, causing an error that
3351 may re-enter this function, there is a recursion check.
3352
3353 Arguments:
3354 reason What $smtp_notquit_reason will be set to in the ACL;
3355 if NULL, the ACL is not run
3356 code The error code to return as part of the response
3357 defaultrespond The default message if there's no user_msg
3358
3359 Returns: Nothing
3360 */
3361
3362 void
3363 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3364 {
3365 int rc;
3366 uschar *user_msg = NULL;
3367 uschar *log_msg = NULL;
3368
3369 /* Check for recursive acll */
3370
3371 if (smtp_exit_function_called)
3372 {
3373 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3374 reason);
3375 return;
3376 }
3377 smtp_exit_function_called = TRUE;
3378
3379 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3380
3381 if (acl_smtp_notquit && reason)
3382 {
3383 smtp_notquit_reason = reason;
3384 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3385 &log_msg)) == ERROR)
3386 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3387 log_msg);
3388 }
3389
3390 /* Write an SMTP response if we are expected to give one. As the default
3391 responses are all internal, they should always fit in the buffer, but code a
3392 warning, just in case. Note that string_vformat() still leaves a complete
3393 string, even if it is incomplete. */
3394
3395 if (code && defaultrespond)
3396 {
3397 if (user_msg)
3398 smtp_respond(code, 3, TRUE, user_msg);
3399 else
3400 {
3401 uschar buffer[128];
3402 va_list ap;
3403 va_start(ap, defaultrespond);
3404 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3405 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3406 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3407 va_end(ap);
3408 }
3409 mac_smtp_fflush();
3410 }
3411 }
3412
3413
3414
3415
3416 /*************************************************
3417 * Verify HELO argument *
3418 *************************************************/
3419
3420 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3421 matched. It is also called from ACL processing if verify = helo is used and
3422 verification was not previously tried (i.e. helo_try_verify_hosts was not
3423 matched). The result of its processing is to set helo_verified and
3424 helo_verify_failed. These variables should both be FALSE for this function to
3425 be called.
3426
3427 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3428 for IPv6 ::ffff: literals.
3429
3430 Argument: none
3431 Returns: TRUE if testing was completed;
3432 FALSE on a temporary failure
3433 */
3434
3435 BOOL
3436 smtp_verify_helo(void)
3437 {
3438 BOOL yield = TRUE;
3439
3440 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3441 sender_helo_name);
3442
3443 if (sender_helo_name == NULL)
3444 {
3445 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3446 }
3447
3448 /* Deal with the case of -bs without an IP address */
3449
3450 else if (sender_host_address == NULL)
3451 {
3452 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3453 helo_verified = TRUE;
3454 }
3455
3456 /* Deal with the more common case when there is a sending IP address */
3457
3458 else if (sender_helo_name[0] == '[')
3459 {
3460 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3461 Ustrlen(sender_host_address)) == 0;
3462
3463 #if HAVE_IPV6
3464 if (!helo_verified)
3465 {
3466 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3467 helo_verified = Ustrncmp(sender_helo_name + 1,
3468 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3469 }
3470 #endif
3471
3472 HDEBUG(D_receive)
3473 { if (helo_verified) debug_printf("matched host address\n"); }
3474 }
3475
3476 /* Do a reverse lookup if one hasn't already given a positive or negative
3477 response. If that fails, or the name doesn't match, try checking with a forward
3478 lookup. */
3479
3480 else
3481 {
3482 if (sender_host_name == NULL && !host_lookup_failed)
3483 yield = host_name_lookup() != DEFER;
3484
3485 /* If a host name is known, check it and all its aliases. */
3486
3487 if (sender_host_name)
3488 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3489 {
3490 sender_helo_dnssec = sender_host_dnssec;
3491 HDEBUG(D_receive) debug_printf("matched host name\n");
3492 }
3493 else
3494 {
3495 uschar **aliases = sender_host_aliases;
3496 while (*aliases)
3497 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3498 {
3499 sender_helo_dnssec = sender_host_dnssec;
3500 break;
3501 }
3502
3503 HDEBUG(D_receive) if (helo_verified)
3504 debug_printf("matched alias %s\n", *(--aliases));
3505 }
3506
3507 /* Final attempt: try a forward lookup of the helo name */
3508
3509 if (!helo_verified)
3510 {
3511 int rc;
3512 host_item h;
3513 dnssec_domains d;
3514 host_item *hh;
3515
3516 h.name = sender_helo_name;
3517 h.address = NULL;
3518 h.mx = MX