2a3873d33e2a44c6fb3c8d7d0c035b985ad4fe4f
[exim.git] / src / src / smtp_in.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2013 */
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
13
14 /* Initialize for TCP wrappers if so configured. It appears that the macro
15 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
16 including that header, and restore its value afterwards. */
17
18 #ifdef USE_TCP_WRAPPERS
19
20 #if HAVE_IPV6
21 #define EXIM_HAVE_IPV6
22 #endif
23 #undef HAVE_IPV6
24 #include <tcpd.h>
25 #undef HAVE_IPV6
26 #ifdef EXIM_HAVE_IPV6
27 #define HAVE_IPV6 TRUE
28 #endif
29
30 int allow_severity = LOG_INFO;
31 int deny_severity = LOG_NOTICE;
32 uschar *tcp_wrappers_name;
33 #endif
34
35
36 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
37 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
38 commands that accept arguments, and this in particular applies to AUTH, where
39 the data can be quite long. More recently this value was 2048 in Exim;
40 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
41 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
42 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
43 we need room to handle large base64-encoded AUTHs for GSSAPI.
44 */
45
46 #define smtp_cmd_buffer_size 16384
47
48 /* Size of buffer for reading SMTP incoming packets */
49
50 #define in_buffer_size 8192
51
52 /* Structure for SMTP command list */
53
54 typedef struct {
55 const char *name;
56 int len;
57 short int cmd;
58 short int has_arg;
59 short int is_mail_cmd;
60 } smtp_cmd_list;
61
62 /* Codes for identifying commands. We order them so that those that come first
63 are those for which synchronization is always required. Checking this can help
64 block some spam. */
65
66 enum {
67 /* These commands are required to be synchronized, i.e. to be the last in a
68 block of commands when pipelining. */
69
70 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
71 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
72 ETRN_CMD, /* This by analogy with TURN from the RFC */
73 STARTTLS_CMD, /* Required by the STARTTLS RFC */
74
75 /* This is a dummy to identify the non-sync commands when pipelining */
76
77 NON_SYNC_CMD_PIPELINING,
78
79 /* These commands need not be synchronized when pipelining */
80
81 MAIL_CMD, RCPT_CMD, RSET_CMD,
82
83 /* This is a dummy to identify the non-sync commands when not pipelining */
84
85 NON_SYNC_CMD_NON_PIPELINING,
86
87 /* I have been unable to find a statement about the use of pipelining
88 with AUTH, so to be on the safe side it is here, though I kind of feel
89 it should be up there with the synchronized commands. */
90
91 AUTH_CMD,
92
93 /* I'm not sure about these, but I don't think they matter. */
94
95 QUIT_CMD, HELP_CMD,
96
97 #ifdef EXPERIMENTAL_PROXY
98 PROXY_FAIL_IGNORE_CMD,
99 #endif
100
101 /* These are specials that don't correspond to actual commands */
102
103 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
104 TOO_MANY_NONMAIL_CMD };
105
106
107 /* This is a convenience macro for adding the identity of an SMTP command
108 to the circular buffer that holds a list of the last n received. */
109
110 #define HAD(n) \
111 smtp_connection_had[smtp_ch_index++] = n; \
112 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
113
114
115 /*************************************************
116 * Local static variables *
117 *************************************************/
118
119 static auth_instance *authenticated_by;
120 static BOOL auth_advertised;
121 #ifdef SUPPORT_TLS
122 static BOOL tls_advertised;
123 #endif
124 static BOOL esmtp;
125 static BOOL helo_required = FALSE;
126 static BOOL helo_verify = FALSE;
127 static BOOL helo_seen;
128 static BOOL helo_accept_junk;
129 static BOOL count_nonmail;
130 static BOOL pipelining_advertised;
131 static BOOL rcpt_smtp_response_same;
132 static BOOL rcpt_in_progress;
133 static int nonmail_command_count;
134 static BOOL smtp_exit_function_called = 0;
135 static int synprot_error_count;
136 static int unknown_command_count;
137 static int sync_cmd_limit;
138 static int smtp_write_error = 0;
139
140 static uschar *rcpt_smtp_response;
141 static uschar *smtp_data_buffer;
142 static uschar *smtp_cmd_data;
143
144 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
145 final fields of all except AUTH are forced TRUE at the start of a new message
146 setup, to allow one of each between messages that is not counted as a nonmail
147 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
148 allow a new EHLO after starting up TLS.
149
150 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
151 counted. However, the flag is changed when AUTH is received, so that multiple
152 failing AUTHs will eventually hit the limit. After a successful AUTH, another
153 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
154 forced TRUE, to allow for the re-authentication that can happen at that point.
155
156 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
157 count of non-mail commands and possibly provoke an error. */
158
159 static smtp_cmd_list cmd_list[] = {
160 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
161 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
162 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
163 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
164 #ifdef SUPPORT_TLS
165 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
166 #endif
167
168 /* If you change anything above here, also fix the definitions below. */
169
170 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
171 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
172 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
173 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
174 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
175 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
176 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
177 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
178 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
179 };
180
181 static smtp_cmd_list *cmd_list_end =
182 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
183
184 #define CMD_LIST_RSET 0
185 #define CMD_LIST_HELO 1
186 #define CMD_LIST_EHLO 2
187 #define CMD_LIST_AUTH 3
188 #define CMD_LIST_STARTTLS 4
189
190 /* This list of names is used for performing the smtp_no_mail logging action.
191 It must be kept in step with the SCH_xxx enumerations. */
192
193 static uschar *smtp_names[] =
194 {
195 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
196 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
197 US"VRFY" };
198
199 static uschar *protocols[] = {
200 US"local-smtp", /* HELO */
201 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
202 US"local-esmtp", /* EHLO */
203 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
204 US"local-esmtpa", /* EHLO->AUTH */
205 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
206 };
207
208 #define pnormal 0
209 #define pextend 2
210 #define pcrpted 1 /* added to pextend or pnormal */
211 #define pauthed 2 /* added to pextend */
212 #define pnlocal 6 /* offset to remove "local" */
213
214 /* Sanity check and validate optional args to MAIL FROM: envelope */
215 enum {
216 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
217 #ifdef EXPERIMENTAL_PRDR
218 ENV_MAIL_OPT_PRDR,
219 #endif
220 ENV_MAIL_OPT_NULL
221 };
222 typedef struct {
223 uschar * name; /* option requested during MAIL cmd */
224 int value; /* enum type */
225 BOOL need_value; /* TRUE requires value (name=value pair format)
226 FALSE is a singleton */
227 } env_mail_type_t;
228 static env_mail_type_t env_mail_type_list[] = {
229 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
230 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
231 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
232 #ifdef EXPERIMENTAL_PRDR
233 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
234 #endif
235 { US"NULL", ENV_MAIL_OPT_NULL, FALSE }
236 };
237
238 /* When reading SMTP from a remote host, we have to use our own versions of the
239 C input-reading functions, in order to be able to flush the SMTP output only
240 when about to read more data from the socket. This is the only way to get
241 optimal performance when the client is using pipelining. Flushing for every
242 command causes a separate packet and reply packet each time; saving all the
243 responses up (when pipelining) combines them into one packet and one response.
244
245 For simplicity, these functions are used for *all* SMTP input, not only when
246 receiving over a socket. However, after setting up a secure socket (SSL), input
247 is read via the OpenSSL library, and another set of functions is used instead
248 (see tls.c).
249
250 These functions are set in the receive_getc etc. variables and called with the
251 same interface as the C functions. However, since there can only ever be
252 one incoming SMTP call, we just use a single buffer and flags. There is no need
253 to implement a complicated private FILE-like structure.*/
254
255 static uschar *smtp_inbuffer;
256 static uschar *smtp_inptr;
257 static uschar *smtp_inend;
258 static int smtp_had_eof;
259 static int smtp_had_error;
260
261
262 /*************************************************
263 * SMTP version of getc() *
264 *************************************************/
265
266 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
267 it flushes the output, and refills the buffer, with a timeout. The signal
268 handler is set appropriately by the calling function. This function is not used
269 after a connection has negotated itself into an TLS/SSL state.
270
271 Arguments: none
272 Returns: the next character or EOF
273 */
274
275 int
276 smtp_getc(void)
277 {
278 if (smtp_inptr >= smtp_inend)
279 {
280 int rc, save_errno;
281 fflush(smtp_out);
282 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
283 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
284 save_errno = errno;
285 alarm(0);
286 if (rc <= 0)
287 {
288 /* Must put the error text in fixed store, because this might be during
289 header reading, where it releases unused store above the header. */
290 if (rc < 0)
291 {
292 smtp_had_error = save_errno;
293 smtp_read_error = string_copy_malloc(
294 string_sprintf(" (error: %s)", strerror(save_errno)));
295 }
296 else smtp_had_eof = 1;
297 return EOF;
298 }
299 #ifndef DISABLE_DKIM
300 dkim_exim_verify_feed(smtp_inbuffer, rc);
301 #endif
302 smtp_inend = smtp_inbuffer + rc;
303 smtp_inptr = smtp_inbuffer;
304 }
305 return *smtp_inptr++;
306 }
307
308
309
310 /*************************************************
311 * SMTP version of ungetc() *
312 *************************************************/
313
314 /* Puts a character back in the input buffer. Only ever
315 called once.
316
317 Arguments:
318 ch the character
319
320 Returns: the character
321 */
322
323 int
324 smtp_ungetc(int ch)
325 {
326 *(--smtp_inptr) = ch;
327 return ch;
328 }
329
330
331
332
333 /*************************************************
334 * SMTP version of feof() *
335 *************************************************/
336
337 /* Tests for a previous EOF
338
339 Arguments: none
340 Returns: non-zero if the eof flag is set
341 */
342
343 int
344 smtp_feof(void)
345 {
346 return smtp_had_eof;
347 }
348
349
350
351
352 /*************************************************
353 * SMTP version of ferror() *
354 *************************************************/
355
356 /* Tests for a previous read error, and returns with errno
357 restored to what it was when the error was detected.
358
359 Arguments: none
360 Returns: non-zero if the error flag is set
361 */
362
363 int
364 smtp_ferror(void)
365 {
366 errno = smtp_had_error;
367 return smtp_had_error;
368 }
369
370
371
372 /*************************************************
373 * Test for characters in the SMTP buffer *
374 *************************************************/
375
376 /* Used at the end of a message
377
378 Arguments: none
379 Returns: TRUE/FALSE
380 */
381
382 BOOL
383 smtp_buffered(void)
384 {
385 return smtp_inptr < smtp_inend;
386 }
387
388
389
390 /*************************************************
391 * Write formatted string to SMTP channel *
392 *************************************************/
393
394 /* This is a separate function so that we don't have to repeat everything for
395 TLS support or debugging. It is global so that the daemon and the
396 authentication functions can use it. It does not return any error indication,
397 because major problems such as dropped connections won't show up till an output
398 flush for non-TLS connections. The smtp_fflush() function is available for
399 checking that: for convenience, TLS output errors are remembered here so that
400 they are also picked up later by smtp_fflush().
401
402 Arguments:
403 format format string
404 ... optional arguments
405
406 Returns: nothing
407 */
408
409 void
410 smtp_printf(const char *format, ...)
411 {
412 va_list ap;
413
414 va_start(ap, format);
415 smtp_vprintf(format, ap);
416 va_end(ap);
417 }
418
419 /* This is split off so that verify.c:respond_printf() can, in effect, call
420 smtp_printf(), bearing in mind that in C a vararg function can't directly
421 call another vararg function, only a function which accepts a va_list. */
422
423 void
424 smtp_vprintf(const char *format, va_list ap)
425 {
426 BOOL yield;
427
428 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
429
430 DEBUG(D_receive)
431 {
432 void *reset_point = store_get(0);
433 uschar *msg_copy, *cr, *end;
434 msg_copy = string_copy(big_buffer);
435 end = msg_copy + Ustrlen(msg_copy);
436 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
437 memmove(cr, cr + 1, (end--) - cr);
438 debug_printf("SMTP>> %s", msg_copy);
439 store_reset(reset_point);
440 }
441
442 if (!yield)
443 {
444 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
445 smtp_closedown(US"Unexpected error");
446 exim_exit(EXIT_FAILURE);
447 }
448
449 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
450 have had the same. Note: this code is also present in smtp_respond(). It would
451 be tidier to have it only in one place, but when it was added, it was easier to
452 do it that way, so as not to have to mess with the code for the RCPT command,
453 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
454
455 if (rcpt_in_progress)
456 {
457 if (rcpt_smtp_response == NULL)
458 rcpt_smtp_response = string_copy(big_buffer);
459 else if (rcpt_smtp_response_same &&
460 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
461 rcpt_smtp_response_same = FALSE;
462 rcpt_in_progress = FALSE;
463 }
464
465 /* Now write the string */
466
467 #ifdef SUPPORT_TLS
468 if (tls_in.active >= 0)
469 {
470 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
471 smtp_write_error = -1;
472 }
473 else
474 #endif
475
476 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
477 }
478
479
480
481 /*************************************************
482 * Flush SMTP out and check for error *
483 *************************************************/
484
485 /* This function isn't currently used within Exim (it detects errors when it
486 tries to read the next SMTP input), but is available for use in local_scan().
487 For non-TLS connections, it flushes the output and checks for errors. For
488 TLS-connections, it checks for a previously-detected TLS write error.
489
490 Arguments: none
491 Returns: 0 for no error; -1 after an error
492 */
493
494 int
495 smtp_fflush(void)
496 {
497 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
498 return smtp_write_error;
499 }
500
501
502
503 /*************************************************
504 * SMTP command read timeout *
505 *************************************************/
506
507 /* Signal handler for timing out incoming SMTP commands. This attempts to
508 finish off tidily.
509
510 Argument: signal number (SIGALRM)
511 Returns: nothing
512 */
513
514 static void
515 command_timeout_handler(int sig)
516 {
517 sig = sig; /* Keep picky compilers happy */
518 log_write(L_lost_incoming_connection,
519 LOG_MAIN, "SMTP command timeout on%s connection from %s",
520 (tls_in.active >= 0)? " TLS" : "",
521 host_and_ident(FALSE));
522 if (smtp_batched_input)
523 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
524 smtp_notquit_exit(US"command-timeout", US"421",
525 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
526 exim_exit(EXIT_FAILURE);
527 }
528
529
530
531 /*************************************************
532 * SIGTERM received *
533 *************************************************/
534
535 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
536
537 Argument: signal number (SIGTERM)
538 Returns: nothing
539 */
540
541 static void
542 command_sigterm_handler(int sig)
543 {
544 sig = sig; /* Keep picky compilers happy */
545 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
546 if (smtp_batched_input)
547 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
548 smtp_notquit_exit(US"signal-exit", US"421",
549 US"%s: Service not available - closing connection", smtp_active_hostname);
550 exim_exit(EXIT_FAILURE);
551 }
552
553
554
555
556 #ifdef EXPERIMENTAL_PROXY
557 /*************************************************
558 * Restore socket timeout to previous value *
559 *************************************************/
560 /* If the previous value was successfully retrieved, restore
561 it before returning control to the non-proxy routines
562
563 Arguments: fd - File descriptor for input
564 get_ok - Successfully retrieved previous values
565 tvtmp - Time struct with previous values
566 vslen - Length of time struct
567 Returns: none
568 */
569 static void
570 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
571 {
572 if (get_ok == 0)
573 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
574 }
575
576 /*************************************************
577 * Check if host is required proxy host *
578 *************************************************/
579 /* The function determines if inbound host will be a regular smtp host
580 or if it is configured that it must use Proxy Protocol.
581
582 Arguments: none
583 Returns: bool
584 */
585
586 static BOOL
587 check_proxy_protocol_host()
588 {
589 int rc;
590 /* Cannot configure local connection as a proxy inbound */
591 if (sender_host_address == NULL) return proxy_session;
592
593 rc = verify_check_this_host(&proxy_required_hosts, NULL, NULL,
594 sender_host_address, NULL);
595 if (rc == OK)
596 {
597 DEBUG(D_receive)
598 debug_printf("Detected proxy protocol configured host\n");
599 proxy_session = TRUE;
600 }
601 return proxy_session;
602 }
603
604
605 /*************************************************
606 * Flush waiting input string *
607 *************************************************/
608 static void
609 flush_input()
610 {
611 int rc;
612
613 rc = smtp_getc();
614 while (rc != '\n') /* End of input string */
615 {
616 rc = smtp_getc();
617 }
618 }
619
620
621 /*************************************************
622 * Setup host for proxy protocol *
623 *************************************************/
624 /* The function configures the connection based on a header from the
625 inbound host to use Proxy Protocol. The specification is very exact
626 so exit with an error if do not find the exact required pieces. This
627 includes an incorrect number of spaces separating args.
628
629 Arguments: none
630 Returns: int
631 */
632
633 static BOOL
634 setup_proxy_protocol_host()
635 {
636 union {
637 struct {
638 uschar line[108];
639 } v1;
640 struct {
641 uschar sig[12];
642 uschar ver;
643 uschar cmd;
644 uschar fam;
645 uschar len;
646 union {
647 struct { /* TCP/UDP over IPv4, len = 12 */
648 uint32_t src_addr;
649 uint32_t dst_addr;
650 uint16_t src_port;
651 uint16_t dst_port;
652 } ip4;
653 struct { /* TCP/UDP over IPv6, len = 36 */
654 uint8_t src_addr[16];
655 uint8_t dst_addr[16];
656 uint16_t src_port;
657 uint16_t dst_port;
658 } ip6;
659 struct { /* AF_UNIX sockets, len = 216 */
660 uschar src_addr[108];
661 uschar dst_addr[108];
662 } unx;
663 } addr;
664 } v2;
665 } hdr;
666
667 int size, ret, fd;
668 uschar *tmpip;
669 const char v2sig[13] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A\x02";
670 uschar *iptype; /* To display debug info */
671 struct timeval tv;
672 int get_ok = 0;
673 socklen_t vslen = 0;
674 struct timeval tvtmp;
675
676 vslen = sizeof(struct timeval);
677
678 fd = fileno(smtp_in);
679
680 /* Save current socket timeout values */
681 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
682 &vslen);
683
684 /* Proxy Protocol host must send header within a short time
685 (default 3 seconds) or it's considered invalid */
686 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
687 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
688 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
689 sizeof(struct timeval));
690
691 do
692 {
693 ret = recv(fd, &hdr, sizeof(hdr), MSG_PEEK);
694 }
695 while (ret == -1 && errno == EINTR);
696
697 if (ret == -1)
698 {
699 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
700 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
701 }
702
703 if (ret >= 16 &&
704 memcmp(&hdr.v2, v2sig, 13) == 0)
705 {
706 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
707 size = 16 + hdr.v2.len;
708 if (ret < size)
709 {
710 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header\n");
711 goto proxyfail;
712 }
713 switch (hdr.v2.cmd)
714 {
715 case 0x01: /* PROXY command */
716 switch (hdr.v2.fam)
717 {
718 case 0x11: /* TCPv4 */
719 tmpip = string_sprintf("%s", hdr.v2.addr.ip4.src_addr);
720 if (!string_is_ip_address(tmpip,NULL))
721 return ERRNO_PROXYFAIL;
722 sender_host_address = tmpip;
723 sender_host_port = hdr.v2.addr.ip4.src_port;
724 goto done;
725 case 0x21: /* TCPv6 */
726 tmpip = string_sprintf("%s", hdr.v2.addr.ip6.src_addr);
727 if (!string_is_ip_address(tmpip,NULL))
728 return ERRNO_PROXYFAIL;
729 sender_host_address = tmpip;
730 sender_host_port = hdr.v2.addr.ip6.src_port;
731 goto done;
732 }
733 /* Unsupported protocol, keep local connection address */
734 break;
735 case 0x00: /* LOCAL command */
736 /* Keep local connection address for LOCAL */
737 break;
738 default:
739 DEBUG(D_receive) debug_printf("Unsupported PROXYv2 command\n");
740 goto proxyfail;
741 }
742 }
743 else if (ret >= 8 &&
744 memcmp(hdr.v1.line, "PROXY", 5) == 0)
745 {
746 uschar *p = string_copy(hdr.v1.line);
747 uschar *end = memchr(p, '\r', ret - 1);
748 uschar *sp; /* Utility variables follow */
749 int tmp_port;
750 char *endc;
751
752 if (!end || end[1] != '\n')
753 {
754 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
755 goto proxyfail;
756 }
757 *end = '\0'; /* Terminate the string */
758 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
759 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
760 /* Step through the string looking for the required fields. Ensure
761 strict adherance to required formatting, exit for any error. */
762 p += 5;
763 if (!isspace(*(p++)))
764 {
765 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
766 goto proxyfail;
767 }
768 if (!Ustrncmp(p, CCS"TCP4", 4))
769 iptype = US"IPv4";
770 else if (!Ustrncmp(p,CCS"TCP6", 4))
771 iptype = US"IPv6";
772 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
773 {
774 iptype = US"Unknown";
775 goto done;
776 }
777 else
778 {
779 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
780 goto proxyfail;
781 }
782
783 p += Ustrlen(iptype);
784 if (!isspace(*(p++)))
785 {
786 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
787 goto proxyfail;
788 }
789 /* Find the end of the arg */
790 if ((sp = Ustrchr(p, ' ')) == NULL)
791 {
792 DEBUG(D_receive)
793 debug_printf("Did not find proxied src %s\n", iptype);
794 goto proxyfail;
795 }
796 *sp = '\0';
797 if(!string_is_ip_address(p,NULL))
798 {
799 DEBUG(D_receive)
800 debug_printf("Proxied src arg is not an %s address\n", iptype);
801 goto proxyfail;
802 }
803 proxy_host_address = sender_host_address;
804 sender_host_address = p;
805 p = sp + 1;
806 if ((sp = Ustrchr(p, ' ')) == NULL)
807 {
808 DEBUG(D_receive)
809 debug_printf("Did not find proxy dest %s\n", iptype);
810 goto proxyfail;
811 }
812 *sp = '\0';
813 if(!string_is_ip_address(p,NULL))
814 {
815 DEBUG(D_receive)
816 debug_printf("Proxy dest arg is not an %s address\n", iptype);
817 goto proxyfail;
818 }
819 /* Should save dest ip somewhere? */
820 p = sp + 1;
821 if ((sp = Ustrchr(p, ' ')) == NULL)
822 {
823 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
824 goto proxyfail;
825 }
826 *sp = '\0';
827 tmp_port = strtol(CCS p,&endc,10);
828 if (*endc || tmp_port == 0)
829 {
830 DEBUG(D_receive)
831 debug_printf("Proxied src port '%s' not an integer\n", p);
832 goto proxyfail;
833 }
834 proxy_host_port = sender_host_port;
835 sender_host_port = tmp_port;
836 p = sp + 1;
837 if ((sp = Ustrchr(p, '\0')) == NULL)
838 {
839 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
840 goto proxyfail;
841 }
842 tmp_port = strtol(CCS p,&endc,10);
843 if (*endc || tmp_port == 0)
844 {
845 DEBUG(D_receive)
846 debug_printf("Proxy dest port '%s' not an integer\n", p);
847 goto proxyfail;
848 }
849 /* Should save dest port somewhere? */
850 /* Already checked for /r /n above. Good V1 header received. */
851 goto done;
852 }
853 else
854 {
855 /* Wrong protocol */
856 DEBUG(D_receive) debug_printf("Wrong proxy protocol specified\n");
857 goto proxyfail;
858 }
859
860 proxyfail:
861 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
862 /* Don't flush any potential buffer contents. Any input should cause a
863 synchronization failure or we just don't want to speak SMTP to them */
864 return FALSE;
865
866 done:
867 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
868 flush_input();
869 DEBUG(D_receive)
870 debug_printf("Valid %s sender from Proxy Protocol header\n",
871 iptype);
872 return proxy_session;
873 }
874 #endif
875
876 /*************************************************
877 * Read one command line *
878 *************************************************/
879
880 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
881 There are sites that don't do this, and in any case internal SMTP probably
882 should check only for LF. Consequently, we check here for LF only. The line
883 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
884 an unknown command. The command is read into the global smtp_cmd_buffer so that
885 it is available via $smtp_command.
886
887 The character reading routine sets up a timeout for each block actually read
888 from the input (which may contain more than one command). We set up a special
889 signal handler that closes down the session on a timeout. Control does not
890 return when it runs.
891
892 Arguments:
893 check_sync if TRUE, check synchronization rules if global option is TRUE
894
895 Returns: a code identifying the command (enumerated above)
896 */
897
898 static int
899 smtp_read_command(BOOL check_sync)
900 {
901 int c;
902 int ptr = 0;
903 smtp_cmd_list *p;
904 BOOL hadnull = FALSE;
905
906 os_non_restarting_signal(SIGALRM, command_timeout_handler);
907
908 while ((c = (receive_getc)()) != '\n' && c != EOF)
909 {
910 if (ptr >= smtp_cmd_buffer_size)
911 {
912 os_non_restarting_signal(SIGALRM, sigalrm_handler);
913 return OTHER_CMD;
914 }
915 if (c == 0)
916 {
917 hadnull = TRUE;
918 c = '?';
919 }
920 smtp_cmd_buffer[ptr++] = c;
921 }
922
923 receive_linecount++; /* For BSMTP errors */
924 os_non_restarting_signal(SIGALRM, sigalrm_handler);
925
926 /* If hit end of file, return pseudo EOF command. Whether we have a
927 part-line already read doesn't matter, since this is an error state. */
928
929 if (c == EOF) return EOF_CMD;
930
931 /* Remove any CR and white space at the end of the line, and terminate the
932 string. */
933
934 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
935 smtp_cmd_buffer[ptr] = 0;
936
937 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
938
939 /* NULLs are not allowed in SMTP commands */
940
941 if (hadnull) return BADCHAR_CMD;
942
943 /* Scan command list and return identity, having set the data pointer
944 to the start of the actual data characters. Check for SMTP synchronization
945 if required. */
946
947 for (p = cmd_list; p < cmd_list_end; p++)
948 {
949 #ifdef EXPERIMENTAL_PROXY
950 /* Only allow QUIT command if Proxy Protocol parsing failed */
951 if (proxy_session && proxy_session_failed)
952 {
953 if (p->cmd != QUIT_CMD)
954 continue;
955 }
956 #endif
957 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
958 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
959 smtp_cmd_buffer[p->len] == 0 ||
960 smtp_cmd_buffer[p->len] == ' '))
961 {
962 if (smtp_inptr < smtp_inend && /* Outstanding input */
963 p->cmd < sync_cmd_limit && /* Command should sync */
964 check_sync && /* Local flag set */
965 smtp_enforce_sync && /* Global flag set */
966 sender_host_address != NULL && /* Not local input */
967 !sender_host_notsocket) /* Really is a socket */
968 return BADSYN_CMD;
969
970 /* The variables $smtp_command and $smtp_command_argument point into the
971 unmodified input buffer. A copy of the latter is taken for actual
972 processing, so that it can be chopped up into separate parts if necessary,
973 for example, when processing a MAIL command options such as SIZE that can
974 follow the sender address. */
975
976 smtp_cmd_argument = smtp_cmd_buffer + p->len;
977 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
978 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
979 smtp_cmd_data = smtp_data_buffer;
980
981 /* Count non-mail commands from those hosts that are controlled in this
982 way. The default is all hosts. We don't waste effort checking the list
983 until we get a non-mail command, but then cache the result to save checking
984 again. If there's a DEFER while checking the host, assume it's in the list.
985
986 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
987 start of each incoming message by fiddling with the value in the table. */
988
989 if (!p->is_mail_cmd)
990 {
991 if (count_nonmail == TRUE_UNSET) count_nonmail =
992 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
993 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
994 return TOO_MANY_NONMAIL_CMD;
995 }
996
997 /* If there is data for a command that does not expect it, generate the
998 error here. */
999
1000 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1001 }
1002 }
1003
1004 #ifdef EXPERIMENTAL_PROXY
1005 /* Only allow QUIT command if Proxy Protocol parsing failed */
1006 if (proxy_session && proxy_session_failed)
1007 return PROXY_FAIL_IGNORE_CMD;
1008 #endif
1009
1010 /* Enforce synchronization for unknown commands */
1011
1012 if (smtp_inptr < smtp_inend && /* Outstanding input */
1013 check_sync && /* Local flag set */
1014 smtp_enforce_sync && /* Global flag set */
1015 sender_host_address != NULL && /* Not local input */
1016 !sender_host_notsocket) /* Really is a socket */
1017 return BADSYN_CMD;
1018
1019 return OTHER_CMD;
1020 }
1021
1022
1023
1024 /*************************************************
1025 * Recheck synchronization *
1026 *************************************************/
1027
1028 /* Synchronization checks can never be perfect because a packet may be on its
1029 way but not arrived when the check is done. Such checks can in any case only be
1030 done when TLS is not in use. Normally, the checks happen when commands are
1031 read: Exim ensures that there is no more input in the input buffer. In normal
1032 cases, the response to the command will be fast, and there is no further check.
1033
1034 However, for some commands an ACL is run, and that can include delays. In those
1035 cases, it is useful to do another check on the input just before sending the
1036 response. This also applies at the start of a connection. This function does
1037 that check by means of the select() function, as long as the facility is not
1038 disabled or inappropriate. A failure of select() is ignored.
1039
1040 When there is unwanted input, we read it so that it appears in the log of the
1041 error.
1042
1043 Arguments: none
1044 Returns: TRUE if all is well; FALSE if there is input pending
1045 */
1046
1047 static BOOL
1048 check_sync(void)
1049 {
1050 int fd, rc;
1051 fd_set fds;
1052 struct timeval tzero;
1053
1054 if (!smtp_enforce_sync || sender_host_address == NULL ||
1055 sender_host_notsocket || tls_in.active >= 0)
1056 return TRUE;
1057
1058 fd = fileno(smtp_in);
1059 FD_ZERO(&fds);
1060 FD_SET(fd, &fds);
1061 tzero.tv_sec = 0;
1062 tzero.tv_usec = 0;
1063 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1064
1065 if (rc <= 0) return TRUE; /* Not ready to read */
1066 rc = smtp_getc();
1067 if (rc < 0) return TRUE; /* End of file or error */
1068
1069 smtp_ungetc(rc);
1070 rc = smtp_inend - smtp_inptr;
1071 if (rc > 150) rc = 150;
1072 smtp_inptr[rc] = 0;
1073 return FALSE;
1074 }
1075
1076
1077
1078 /*************************************************
1079 * Forced closedown of call *
1080 *************************************************/
1081
1082 /* This function is called from log.c when Exim is dying because of a serious
1083 disaster, and also from some other places. If an incoming non-batched SMTP
1084 channel is open, it swallows the rest of the incoming message if in the DATA
1085 phase, sends the reply string, and gives an error to all subsequent commands
1086 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1087 smtp_in.
1088
1089 Arguments:
1090 message SMTP reply string to send, excluding the code
1091
1092 Returns: nothing
1093 */
1094
1095 void
1096 smtp_closedown(uschar *message)
1097 {
1098 if (smtp_in == NULL || smtp_batched_input) return;
1099 receive_swallow_smtp();
1100 smtp_printf("421 %s\r\n", message);
1101
1102 for (;;)
1103 {
1104 switch(smtp_read_command(FALSE))
1105 {
1106 case EOF_CMD:
1107 return;
1108
1109 case QUIT_CMD:
1110 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1111 mac_smtp_fflush();
1112 return;
1113
1114 case RSET_CMD:
1115 smtp_printf("250 Reset OK\r\n");
1116 break;
1117
1118 default:
1119 smtp_printf("421 %s\r\n", message);
1120 break;
1121 }
1122 }
1123 }
1124
1125
1126
1127
1128 /*************************************************
1129 * Set up connection info for logging *
1130 *************************************************/
1131
1132 /* This function is called when logging information about an SMTP connection.
1133 It sets up appropriate source information, depending on the type of connection.
1134 If sender_fullhost is NULL, we are at a very early stage of the connection;
1135 just use the IP address.
1136
1137 Argument: none
1138 Returns: a string describing the connection
1139 */
1140
1141 uschar *
1142 smtp_get_connection_info(void)
1143 {
1144 uschar *hostname = (sender_fullhost == NULL)?
1145 sender_host_address : sender_fullhost;
1146
1147 if (host_checking)
1148 return string_sprintf("SMTP connection from %s", hostname);
1149
1150 if (sender_host_unknown || sender_host_notsocket)
1151 return string_sprintf("SMTP connection from %s", sender_ident);
1152
1153 if (is_inetd)
1154 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1155
1156 if ((log_extra_selector & LX_incoming_interface) != 0 &&
1157 interface_address != NULL)
1158 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1159 interface_address, interface_port);
1160
1161 return string_sprintf("SMTP connection from %s", hostname);
1162 }
1163
1164
1165
1166 #ifdef SUPPORT_TLS
1167 /* Append TLS-related information to a log line
1168
1169 Arguments:
1170 s String under construction: allocated string to extend, or NULL
1171 sizep Pointer to current allocation size (update on return), or NULL
1172 ptrp Pointer to index for new entries in string (update on return), or NULL
1173
1174 Returns: Allocated string or NULL
1175 */
1176 static uschar *
1177 s_tlslog(uschar * s, int * sizep, int * ptrp)
1178 {
1179 int size = sizep ? *sizep : 0;
1180 int ptr = ptrp ? *ptrp : 0;
1181
1182 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_in.cipher != NULL)
1183 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1184 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
1185 tls_in.cipher != NULL)
1186 s = string_append(s, &size, &ptr, 2, US" CV=",
1187 tls_in.certificate_verified? "yes":"no");
1188 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_in.peerdn != NULL)
1189 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1190 string_printing(tls_in.peerdn), US"\"");
1191 if ((log_extra_selector & LX_tls_sni) != 0 && tls_in.sni != NULL)
1192 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1193 string_printing(tls_in.sni), US"\"");
1194
1195 if (s)
1196 {
1197 s[ptr] = '\0';
1198 if (sizep) *sizep = size;
1199 if (ptrp) *ptrp = ptr;
1200 }
1201 return s;
1202 }
1203 #endif
1204
1205 /*************************************************
1206 * Log lack of MAIL if so configured *
1207 *************************************************/
1208
1209 /* This function is called when an SMTP session ends. If the log selector
1210 smtp_no_mail is set, write a log line giving some details of what has happened
1211 in the SMTP session.
1212
1213 Arguments: none
1214 Returns: nothing
1215 */
1216
1217 void
1218 smtp_log_no_mail(void)
1219 {
1220 int size, ptr, i;
1221 uschar *s, *sep;
1222
1223 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
1224 return;
1225
1226 s = NULL;
1227 size = ptr = 0;
1228
1229 if (sender_host_authenticated != NULL)
1230 {
1231 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1232 if (authenticated_id != NULL)
1233 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1234 }
1235
1236 #ifdef SUPPORT_TLS
1237 s = s_tlslog(s, &size, &ptr);
1238 #endif
1239
1240 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1241 US" C=..." : US" C=";
1242 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1243 {
1244 if (smtp_connection_had[i] != SCH_NONE)
1245 {
1246 s = string_append(s, &size, &ptr, 2, sep,
1247 smtp_names[smtp_connection_had[i]]);
1248 sep = US",";
1249 }
1250 }
1251
1252 for (i = 0; i < smtp_ch_index; i++)
1253 {
1254 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1255 sep = US",";
1256 }
1257
1258 if (s != NULL) s[ptr] = 0; else s = US"";
1259 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1260 host_and_ident(FALSE),
1261 readconf_printtime(time(NULL) - smtp_connection_start), s);
1262 }
1263
1264
1265
1266 /*************************************************
1267 * Check HELO line and set sender_helo_name *
1268 *************************************************/
1269
1270 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1271 the domain name of the sending host, or an ip literal in square brackets. The
1272 arrgument is placed in sender_helo_name, which is in malloc store, because it
1273 must persist over multiple incoming messages. If helo_accept_junk is set, this
1274 host is permitted to send any old junk (needed for some broken hosts).
1275 Otherwise, helo_allow_chars can be used for rogue characters in general
1276 (typically people want to let in underscores).
1277
1278 Argument:
1279 s the data portion of the line (already past any white space)
1280
1281 Returns: TRUE or FALSE
1282 */
1283
1284 static BOOL
1285 check_helo(uschar *s)
1286 {
1287 uschar *start = s;
1288 uschar *end = s + Ustrlen(s);
1289 BOOL yield = helo_accept_junk;
1290
1291 /* Discard any previous helo name */
1292
1293 if (sender_helo_name != NULL)
1294 {
1295 store_free(sender_helo_name);
1296 sender_helo_name = NULL;
1297 }
1298
1299 /* Skip tests if junk is permitted. */
1300
1301 if (!yield)
1302 {
1303 /* Allow the new standard form for IPv6 address literals, namely,
1304 [IPv6:....], and because someone is bound to use it, allow an equivalent
1305 IPv4 form. Allow plain addresses as well. */
1306
1307 if (*s == '[')
1308 {
1309 if (end[-1] == ']')
1310 {
1311 end[-1] = 0;
1312 if (strncmpic(s, US"[IPv6:", 6) == 0)
1313 yield = (string_is_ip_address(s+6, NULL) == 6);
1314 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1315 yield = (string_is_ip_address(s+6, NULL) == 4);
1316 else
1317 yield = (string_is_ip_address(s+1, NULL) != 0);
1318 end[-1] = ']';
1319 }
1320 }
1321
1322 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1323 that have been configured (usually underscore - sigh). */
1324
1325 else if (*s != 0)
1326 {
1327 yield = TRUE;
1328 while (*s != 0)
1329 {
1330 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1331 Ustrchr(helo_allow_chars, *s) == NULL)
1332 {
1333 yield = FALSE;
1334 break;
1335 }
1336 s++;
1337 }
1338 }
1339 }
1340
1341 /* Save argument if OK */
1342
1343 if (yield) sender_helo_name = string_copy_malloc(start);
1344 return yield;
1345 }
1346
1347
1348
1349
1350
1351 /*************************************************
1352 * Extract SMTP command option *
1353 *************************************************/
1354
1355 /* This function picks the next option setting off the end of smtp_cmd_data. It
1356 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1357 things that can appear there.
1358
1359 Arguments:
1360 name point this at the name
1361 value point this at the data string
1362
1363 Returns: TRUE if found an option
1364 */
1365
1366 static BOOL
1367 extract_option(uschar **name, uschar **value)
1368 {
1369 uschar *n;
1370 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1371 while (isspace(*v)) v--;
1372 v[1] = 0;
1373 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1374
1375 n = v;
1376 if (*v == '=')
1377 {
1378 while(isalpha(n[-1])) n--;
1379 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1380 if (!isspace(n[-1])) return FALSE;
1381 n[-1] = 0;
1382 }
1383 else
1384 {
1385 n++;
1386 if (v == smtp_cmd_data) return FALSE;
1387 }
1388 *v++ = 0;
1389 *name = n;
1390 *value = v;
1391 return TRUE;
1392 }
1393
1394
1395
1396
1397
1398 /*************************************************
1399 * Reset for new message *
1400 *************************************************/
1401
1402 /* This function is called whenever the SMTP session is reset from
1403 within either of the setup functions.
1404
1405 Argument: the stacking pool storage reset point
1406 Returns: nothing
1407 */
1408
1409 static void
1410 smtp_reset(void *reset_point)
1411 {
1412 store_reset(reset_point);
1413 recipients_list = NULL;
1414 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1415 raw_recipients_count = recipients_count = recipients_list_max = 0;
1416 cancel_cutthrough_connection("smtp reset");
1417 message_linecount = 0;
1418 message_size = -1;
1419 acl_added_headers = NULL;
1420 acl_removed_headers = NULL;
1421 queue_only_policy = FALSE;
1422 rcpt_smtp_response = NULL;
1423 rcpt_smtp_response_same = TRUE;
1424 rcpt_in_progress = FALSE;
1425 deliver_freeze = FALSE; /* Can be set by ACL */
1426 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1427 fake_response = OK; /* Can be set by ACL */
1428 #ifdef WITH_CONTENT_SCAN
1429 no_mbox_unspool = FALSE; /* Can be set by ACL */
1430 #endif
1431 submission_mode = FALSE; /* Can be set by ACL */
1432 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1433 active_local_from_check = local_from_check; /* Can be set by ACL */
1434 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1435 sender_address = NULL;
1436 submission_name = NULL; /* Can be set by ACL */
1437 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1438 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1439 sender_verified_list = NULL; /* No senders verified */
1440 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1441 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1442 authenticated_sender = NULL;
1443 #ifdef EXPERIMENTAL_BRIGHTMAIL
1444 bmi_run = 0;
1445 bmi_verdicts = NULL;
1446 #endif
1447 #ifndef DISABLE_DKIM
1448 dkim_signers = NULL;
1449 dkim_disable_verify = FALSE;
1450 dkim_collect_input = FALSE;
1451 #endif
1452 #ifdef EXPERIMENTAL_SPF
1453 spf_header_comment = NULL;
1454 spf_received = NULL;
1455 spf_result = NULL;
1456 spf_smtp_comment = NULL;
1457 #endif
1458 body_linecount = body_zerocount = 0;
1459
1460 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1461 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1462 /* Note that ratelimiters_conn persists across resets. */
1463
1464 /* Reset message ACL variables */
1465
1466 acl_var_m = NULL;
1467
1468 /* The message body variables use malloc store. They may be set if this is
1469 not the first message in an SMTP session and the previous message caused them
1470 to be referenced in an ACL. */
1471
1472 if (message_body != NULL)
1473 {
1474 store_free(message_body);
1475 message_body = NULL;
1476 }
1477
1478 if (message_body_end != NULL)
1479 {
1480 store_free(message_body_end);
1481 message_body_end = NULL;
1482 }
1483
1484 /* Warning log messages are also saved in malloc store. They are saved to avoid
1485 repetition in the same message, but it seems right to repeat them for different
1486 messages. */
1487
1488 while (acl_warn_logged != NULL)
1489 {
1490 string_item *this = acl_warn_logged;
1491 acl_warn_logged = acl_warn_logged->next;
1492 store_free(this);
1493 }
1494 }
1495
1496
1497
1498
1499
1500 /*************************************************
1501 * Initialize for incoming batched SMTP message *
1502 *************************************************/
1503
1504 /* This function is called from smtp_setup_msg() in the case when
1505 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1506 of messages in one file with SMTP commands between them. All errors must be
1507 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1508 relevant. After an error on a sender, or an invalid recipient, the remainder
1509 of the message is skipped. The value of received_protocol is already set.
1510
1511 Argument: none
1512 Returns: > 0 message successfully started (reached DATA)
1513 = 0 QUIT read or end of file reached
1514 < 0 should not occur
1515 */
1516
1517 static int
1518 smtp_setup_batch_msg(void)
1519 {
1520 int done = 0;
1521 void *reset_point = store_get(0);
1522
1523 /* Save the line count at the start of each transaction - single commands
1524 like HELO and RSET count as whole transactions. */
1525
1526 bsmtp_transaction_linecount = receive_linecount;
1527
1528 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1529
1530 smtp_reset(reset_point); /* Reset for start of message */
1531
1532 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1533 value. The values are 2 larger than the required yield of the function. */
1534
1535 while (done <= 0)
1536 {
1537 uschar *errmess;
1538 uschar *recipient = NULL;
1539 int start, end, sender_domain, recipient_domain;
1540
1541 switch(smtp_read_command(FALSE))
1542 {
1543 /* The HELO/EHLO commands set sender_address_helo if they have
1544 valid data; otherwise they are ignored, except that they do
1545 a reset of the state. */
1546
1547 case HELO_CMD:
1548 case EHLO_CMD:
1549
1550 check_helo(smtp_cmd_data);
1551 /* Fall through */
1552
1553 case RSET_CMD:
1554 smtp_reset(reset_point);
1555 bsmtp_transaction_linecount = receive_linecount;
1556 break;
1557
1558
1559 /* The MAIL FROM command requires an address as an operand. All we
1560 do here is to parse it for syntactic correctness. The form "<>" is
1561 a special case which converts into an empty string. The start/end
1562 pointers in the original are not used further for this address, as
1563 it is the canonical extracted address which is all that is kept. */
1564
1565 case MAIL_CMD:
1566 if (sender_address != NULL)
1567 /* The function moan_smtp_batch() does not return. */
1568 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1569
1570 if (smtp_cmd_data[0] == 0)
1571 /* The function moan_smtp_batch() does not return. */
1572 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1573
1574 /* Reset to start of message */
1575
1576 smtp_reset(reset_point);
1577
1578 /* Apply SMTP rewrite */
1579
1580 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1581 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1582 US"", global_rewrite_rules) : smtp_cmd_data;
1583
1584 /* Extract the address; the TRUE flag allows <> as valid */
1585
1586 raw_sender =
1587 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1588 TRUE);
1589
1590 if (raw_sender == NULL)
1591 /* The function moan_smtp_batch() does not return. */
1592 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1593
1594 sender_address = string_copy(raw_sender);
1595
1596 /* Qualify unqualified sender addresses if permitted to do so. */
1597
1598 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1599 {
1600 if (allow_unqualified_sender)
1601 {
1602 sender_address = rewrite_address_qualify(sender_address, FALSE);
1603 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1604 "and rewritten\n", raw_sender);
1605 }
1606 /* The function moan_smtp_batch() does not return. */
1607 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1608 "a domain");
1609 }
1610 break;
1611
1612
1613 /* The RCPT TO command requires an address as an operand. All we do
1614 here is to parse it for syntactic correctness. There may be any number
1615 of RCPT TO commands, specifying multiple senders. We build them all into
1616 a data structure that is in argc/argv format. The start/end values
1617 given by parse_extract_address are not used, as we keep only the
1618 extracted address. */
1619
1620 case RCPT_CMD:
1621 if (sender_address == NULL)
1622 /* The function moan_smtp_batch() does not return. */
1623 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1624
1625 if (smtp_cmd_data[0] == 0)
1626 /* The function moan_smtp_batch() does not return. */
1627 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1628
1629 /* Check maximum number allowed */
1630
1631 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1632 /* The function moan_smtp_batch() does not return. */
1633 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1634 recipients_max_reject? "552": "452");
1635
1636 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1637 recipient address */
1638
1639 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1640 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1641 global_rewrite_rules) : smtp_cmd_data;
1642
1643 /* rfc821_domains = TRUE; << no longer needed */
1644 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1645 &recipient_domain, FALSE);
1646 /* rfc821_domains = FALSE; << no longer needed */
1647
1648 if (recipient == NULL)
1649 /* The function moan_smtp_batch() does not return. */
1650 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1651
1652 /* If the recipient address is unqualified, qualify it if permitted. Then
1653 add it to the list of recipients. */
1654
1655 if (recipient_domain == 0)
1656 {
1657 if (allow_unqualified_recipient)
1658 {
1659 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1660 recipient);
1661 recipient = rewrite_address_qualify(recipient, TRUE);
1662 }
1663 /* The function moan_smtp_batch() does not return. */
1664 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1665 "a domain");
1666 }
1667 receive_add_recipient(recipient, -1);
1668 break;
1669
1670
1671 /* The DATA command is legal only if it follows successful MAIL FROM
1672 and RCPT TO commands. This function is complete when a valid DATA
1673 command is encountered. */
1674
1675 case DATA_CMD:
1676 if (sender_address == NULL || recipients_count <= 0)
1677 {
1678 /* The function moan_smtp_batch() does not return. */
1679 if (sender_address == NULL)
1680 moan_smtp_batch(smtp_cmd_buffer,
1681 "503 MAIL FROM:<sender> command must precede DATA");
1682 else
1683 moan_smtp_batch(smtp_cmd_buffer,
1684 "503 RCPT TO:<recipient> must precede DATA");
1685 }
1686 else
1687 {
1688 done = 3; /* DATA successfully achieved */
1689 message_ended = END_NOTENDED; /* Indicate in middle of message */
1690 }
1691 break;
1692
1693
1694 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1695
1696 case VRFY_CMD:
1697 case EXPN_CMD:
1698 case HELP_CMD:
1699 case NOOP_CMD:
1700 case ETRN_CMD:
1701 bsmtp_transaction_linecount = receive_linecount;
1702 break;
1703
1704
1705 case EOF_CMD:
1706 case QUIT_CMD:
1707 done = 2;
1708 break;
1709
1710
1711 case BADARG_CMD:
1712 /* The function moan_smtp_batch() does not return. */
1713 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1714 break;
1715
1716
1717 case BADCHAR_CMD:
1718 /* The function moan_smtp_batch() does not return. */
1719 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1720 break;
1721
1722
1723 default:
1724 /* The function moan_smtp_batch() does not return. */
1725 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1726 break;
1727 }
1728 }
1729
1730 return done - 2; /* Convert yield values */
1731 }
1732
1733
1734
1735
1736 /*************************************************
1737 * Start an SMTP session *
1738 *************************************************/
1739
1740 /* This function is called at the start of an SMTP session. Thereafter,
1741 smtp_setup_msg() is called to initiate each separate message. This
1742 function does host-specific testing, and outputs the banner line.
1743
1744 Arguments: none
1745 Returns: FALSE if the session can not continue; something has
1746 gone wrong, or the connection to the host is blocked
1747 */
1748
1749 BOOL
1750 smtp_start_session(void)
1751 {
1752 int size = 256;
1753 int ptr, esclen;
1754 uschar *user_msg, *log_msg;
1755 uschar *code, *esc;
1756 uschar *p, *s, *ss;
1757
1758 smtp_connection_start = time(NULL);
1759 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1760 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1761 smtp_ch_index = 0;
1762
1763 /* Default values for certain variables */
1764
1765 helo_seen = esmtp = helo_accept_junk = FALSE;
1766 smtp_mailcmd_count = 0;
1767 count_nonmail = TRUE_UNSET;
1768 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1769 smtp_delay_mail = smtp_rlm_base;
1770 auth_advertised = FALSE;
1771 pipelining_advertised = FALSE;
1772 pipelining_enable = TRUE;
1773 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1774 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1775
1776 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1777
1778 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1779 authentication settings from -oMaa to remain in force. */
1780
1781 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1782 authenticated_by = NULL;
1783
1784 #ifdef SUPPORT_TLS
1785 tls_in.cipher = tls_in.peerdn = NULL;
1786 tls_advertised = FALSE;
1787 #endif
1788
1789 /* Reset ACL connection variables */
1790
1791 acl_var_c = NULL;
1792
1793 /* Allow for trailing 0 in the command and data buffers. */
1794
1795 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1796 if (smtp_cmd_buffer == NULL)
1797 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1798 "malloc() failed for SMTP command buffer");
1799 smtp_cmd_buffer[0] = 0;
1800 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1801
1802 /* For batched input, the protocol setting can be overridden from the
1803 command line by a trusted caller. */
1804
1805 if (smtp_batched_input)
1806 {
1807 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1808 }
1809
1810 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1811 reset later if any of EHLO/AUTH/STARTTLS are received. */
1812
1813 else
1814 received_protocol =
1815 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1816
1817 /* Set up the buffer for inputting using direct read() calls, and arrange to
1818 call the local functions instead of the standard C ones. */
1819
1820 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1821 if (smtp_inbuffer == NULL)
1822 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1823 receive_getc = smtp_getc;
1824 receive_ungetc = smtp_ungetc;
1825 receive_feof = smtp_feof;
1826 receive_ferror = smtp_ferror;
1827 receive_smtp_buffered = smtp_buffered;
1828 smtp_inptr = smtp_inend = smtp_inbuffer;
1829 smtp_had_eof = smtp_had_error = 0;
1830
1831 /* Set up the message size limit; this may be host-specific */
1832
1833 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1834 if (expand_string_message != NULL)
1835 {
1836 if (thismessage_size_limit == -1)
1837 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1838 "%s", expand_string_message);
1839 else
1840 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1841 "%s", expand_string_message);
1842 smtp_closedown(US"Temporary local problem - please try later");
1843 return FALSE;
1844 }
1845
1846 /* When a message is input locally via the -bs or -bS options, sender_host_
1847 unknown is set unless -oMa was used to force an IP address, in which case it
1848 is checked like a real remote connection. When -bs is used from inetd, this
1849 flag is not set, causing the sending host to be checked. The code that deals
1850 with IP source routing (if configured) is never required for -bs or -bS and
1851 the flag sender_host_notsocket is used to suppress it.
1852
1853 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1854 reserve for certain hosts and/or networks. */
1855
1856 if (!sender_host_unknown)
1857 {
1858 int rc;
1859 BOOL reserved_host = FALSE;
1860
1861 /* Look up IP options (source routing info) on the socket if this is not an
1862 -oMa "host", and if any are found, log them and drop the connection.
1863
1864 Linux (and others now, see below) is different to everyone else, so there
1865 has to be some conditional compilation here. Versions of Linux before 2.1.15
1866 used a structure whose name was "options". Somebody finally realized that
1867 this name was silly, and it got changed to "ip_options". I use the
1868 newer name here, but there is a fudge in the script that sets up os.h
1869 to define a macro in older Linux systems.
1870
1871 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1872 glibc 2, which has chosen ip_opts for the structure name. This is now
1873 really a glibc thing rather than a Linux thing, so the condition name
1874 has been changed to reflect this. It is relevant also to GNU/Hurd.
1875
1876 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1877 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1878 a special macro defined in the os.h file.
1879
1880 Some DGUX versions on older hardware appear not to support IP options at
1881 all, so there is now a general macro which can be set to cut out this
1882 support altogether.
1883
1884 How to do this properly in IPv6 is not yet known. */
1885
1886 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1887
1888 #ifdef GLIBC_IP_OPTIONS
1889 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1890 #define OPTSTYLE 1
1891 #else
1892 #define OPTSTYLE 2
1893 #endif
1894 #elif defined DARWIN_IP_OPTIONS
1895 #define OPTSTYLE 2
1896 #else
1897 #define OPTSTYLE 3
1898 #endif
1899
1900 if (!host_checking && !sender_host_notsocket)
1901 {
1902 #if OPTSTYLE == 1
1903 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1904 struct ip_options *ipopt = store_get(optlen);
1905 #elif OPTSTYLE == 2
1906 struct ip_opts ipoptblock;
1907 struct ip_opts *ipopt = &ipoptblock;
1908 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1909 #else
1910 struct ipoption ipoptblock;
1911 struct ipoption *ipopt = &ipoptblock;
1912 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1913 #endif
1914
1915 /* Occasional genuine failures of getsockopt() have been seen - for
1916 example, "reset by peer". Therefore, just log and give up on this
1917 call, unless the error is ENOPROTOOPT. This error is given by systems
1918 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1919 of writing. So for that error, carry on - we just can't do an IP options
1920 check. */
1921
1922 DEBUG(D_receive) debug_printf("checking for IP options\n");
1923
1924 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1925 &optlen) < 0)
1926 {
1927 if (errno != ENOPROTOOPT)
1928 {
1929 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1930 host_and_ident(FALSE), strerror(errno));
1931 smtp_printf("451 SMTP service not available\r\n");
1932 return FALSE;
1933 }
1934 }
1935
1936 /* Deal with any IP options that are set. On the systems I have looked at,
1937 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1938 more logging data than will fit in big_buffer. Nevertheless, after somebody
1939 questioned this code, I've added in some paranoid checking. */
1940
1941 else if (optlen > 0)
1942 {
1943 uschar *p = big_buffer;
1944 uschar *pend = big_buffer + big_buffer_size;
1945 uschar *opt, *adptr;
1946 int optcount;
1947 struct in_addr addr;
1948
1949 #if OPTSTYLE == 1
1950 uschar *optstart = (uschar *)(ipopt->__data);
1951 #elif OPTSTYLE == 2
1952 uschar *optstart = (uschar *)(ipopt->ip_opts);
1953 #else
1954 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1955 #endif
1956
1957 DEBUG(D_receive) debug_printf("IP options exist\n");
1958
1959 Ustrcpy(p, "IP options on incoming call:");
1960 p += Ustrlen(p);
1961
1962 for (opt = optstart; opt != NULL &&
1963 opt < (uschar *)(ipopt) + optlen;)
1964 {
1965 switch (*opt)
1966 {
1967 case IPOPT_EOL:
1968 opt = NULL;
1969 break;
1970
1971 case IPOPT_NOP:
1972 opt++;
1973 break;
1974
1975 case IPOPT_SSRR:
1976 case IPOPT_LSRR:
1977 if (!string_format(p, pend-p, " %s [@%s",
1978 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1979 #if OPTSTYLE == 1
1980 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1981 #elif OPTSTYLE == 2
1982 inet_ntoa(ipopt->ip_dst)))
1983 #else
1984 inet_ntoa(ipopt->ipopt_dst)))
1985 #endif
1986 {
1987 opt = NULL;
1988 break;
1989 }
1990
1991 p += Ustrlen(p);
1992 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1993 adptr = opt + 3;
1994 while (optcount-- > 0)
1995 {
1996 memcpy(&addr, adptr, sizeof(addr));
1997 if (!string_format(p, pend - p - 1, "%s%s",
1998 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1999 {
2000 opt = NULL;
2001 break;
2002 }
2003 p += Ustrlen(p);
2004 adptr += sizeof(struct in_addr);
2005 }
2006 *p++ = ']';
2007 opt += opt[1];
2008 break;
2009
2010 default:
2011 {
2012 int i;
2013 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2014 Ustrcat(p, "[ ");
2015 p += 2;
2016 for (i = 0; i < opt[1]; i++)
2017 {
2018 sprintf(CS p, "%2.2x ", opt[i]);
2019 p += 3;
2020 }
2021 *p++ = ']';
2022 }
2023 opt += opt[1];
2024 break;
2025 }
2026 }
2027
2028 *p = 0;
2029 log_write(0, LOG_MAIN, "%s", big_buffer);
2030
2031 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2032
2033 log_write(0, LOG_MAIN|LOG_REJECT,
2034 "connection from %s refused (IP options)", host_and_ident(FALSE));
2035
2036 smtp_printf("554 SMTP service not available\r\n");
2037 return FALSE;
2038 }
2039
2040 /* Length of options = 0 => there are no options */
2041
2042 else DEBUG(D_receive) debug_printf("no IP options found\n");
2043 }
2044 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2045
2046 /* Set keep-alive in socket options. The option is on by default. This
2047 setting is an attempt to get rid of some hanging connections that stick in
2048 read() when the remote end (usually a dialup) goes away. */
2049
2050 if (smtp_accept_keepalive && !sender_host_notsocket)
2051 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2052
2053 /* If the current host matches host_lookup, set the name by doing a
2054 reverse lookup. On failure, sender_host_name will be NULL and
2055 host_lookup_failed will be TRUE. This may or may not be serious - optional
2056 checks later. */
2057
2058 if (verify_check_host(&host_lookup) == OK)
2059 {
2060 (void)host_name_lookup();
2061 host_build_sender_fullhost();
2062 }
2063
2064 /* Delay this until we have the full name, if it is looked up. */
2065
2066 set_process_info("handling incoming connection from %s",
2067 host_and_ident(FALSE));
2068
2069 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2070 smtps port for use with older style SSL MTAs. */
2071
2072 #ifdef SUPPORT_TLS
2073 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2074 return FALSE;
2075 #endif
2076
2077 /* Test for explicit connection rejection */
2078
2079 if (verify_check_host(&host_reject_connection) == OK)
2080 {
2081 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2082 "from %s (host_reject_connection)", host_and_ident(FALSE));
2083 smtp_printf("554 SMTP service not available\r\n");
2084 return FALSE;
2085 }
2086
2087 /* Test with TCP Wrappers if so configured. There is a problem in that
2088 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2089 such as disks dying. In these cases, it is desirable to reject with a 4xx
2090 error instead of a 5xx error. There isn't a "right" way to detect such
2091 problems. The following kludge is used: errno is zeroed before calling
2092 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2093 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2094 not exist). */
2095
2096 #ifdef USE_TCP_WRAPPERS
2097 errno = 0;
2098 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2099 if (tcp_wrappers_name == NULL)
2100 {
2101 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2102 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2103 expand_string_message);
2104 }
2105 if (!hosts_ctl(tcp_wrappers_name,
2106 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2107 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2108 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2109 {
2110 if (errno == 0 || errno == ENOENT)
2111 {
2112 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2113 log_write(L_connection_reject,
2114 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2115 "(tcp wrappers)", host_and_ident(FALSE));
2116 smtp_printf("554 SMTP service not available\r\n");
2117 }
2118 else
2119 {
2120 int save_errno = errno;
2121 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2122 "errno value %d\n", save_errno);
2123 log_write(L_connection_reject,
2124 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2125 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2126 smtp_printf("451 Temporary local problem - please try later\r\n");
2127 }
2128 return FALSE;
2129 }
2130 #endif
2131
2132 /* Check for reserved slots. The value of smtp_accept_count has already been
2133 incremented to include this process. */
2134
2135 if (smtp_accept_max > 0 &&
2136 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2137 {
2138 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2139 {
2140 log_write(L_connection_reject,
2141 LOG_MAIN, "temporarily refused connection from %s: not in "
2142 "reserve list: connected=%d max=%d reserve=%d%s",
2143 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2144 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2145 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2146 "please try again later\r\n", smtp_active_hostname);
2147 return FALSE;
2148 }
2149 reserved_host = TRUE;
2150 }
2151
2152 /* If a load level above which only messages from reserved hosts are
2153 accepted is set, check the load. For incoming calls via the daemon, the
2154 check is done in the superior process if there are no reserved hosts, to
2155 save a fork. In all cases, the load average will already be available
2156 in a global variable at this point. */
2157
2158 if (smtp_load_reserve >= 0 &&
2159 load_average > smtp_load_reserve &&
2160 !reserved_host &&
2161 verify_check_host(&smtp_reserve_hosts) != OK)
2162 {
2163 log_write(L_connection_reject,
2164 LOG_MAIN, "temporarily refused connection from %s: not in "
2165 "reserve list and load average = %.2f", host_and_ident(FALSE),
2166 (double)load_average/1000.0);
2167 smtp_printf("421 %s: Too much load; please try again later\r\n",
2168 smtp_active_hostname);
2169 return FALSE;
2170 }
2171
2172 /* Determine whether unqualified senders or recipients are permitted
2173 for this host. Unfortunately, we have to do this every time, in order to
2174 set the flags so that they can be inspected when considering qualifying
2175 addresses in the headers. For a site that permits no qualification, this
2176 won't take long, however. */
2177
2178 allow_unqualified_sender =
2179 verify_check_host(&sender_unqualified_hosts) == OK;
2180
2181 allow_unqualified_recipient =
2182 verify_check_host(&recipient_unqualified_hosts) == OK;
2183
2184 /* Determine whether HELO/EHLO is required for this host. The requirement
2185 can be hard or soft. */
2186
2187 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2188 if (!helo_required)
2189 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2190
2191 /* Determine whether this hosts is permitted to send syntactic junk
2192 after a HELO or EHLO command. */
2193
2194 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2195 }
2196
2197 /* For batch SMTP input we are now done. */
2198
2199 if (smtp_batched_input) return TRUE;
2200
2201 #ifdef EXPERIMENTAL_PROXY
2202 /* If valid Proxy Protocol source is connecting, set up session.
2203 * Failure will not allow any SMTP function other than QUIT. */
2204 proxy_session = FALSE;
2205 proxy_session_failed = FALSE;
2206 if (check_proxy_protocol_host())
2207 {
2208 if (setup_proxy_protocol_host() == FALSE)
2209 {
2210 proxy_session_failed = TRUE;
2211 DEBUG(D_receive)
2212 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2213 }
2214 else
2215 {
2216 sender_host_name = NULL;
2217 (void)host_name_lookup();
2218 host_build_sender_fullhost();
2219 }
2220 }
2221 #endif
2222
2223 /* Run the ACL if it exists */
2224
2225 user_msg = NULL;
2226 if (acl_smtp_connect != NULL)
2227 {
2228 int rc;
2229 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2230 &log_msg);
2231 if (rc != OK)
2232 {
2233 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2234 return FALSE;
2235 }
2236 }
2237
2238 /* Output the initial message for a two-way SMTP connection. It may contain
2239 newlines, which then cause a multi-line response to be given. */
2240
2241 code = US"220"; /* Default status code */
2242 esc = US""; /* Default extended status code */
2243 esclen = 0; /* Length of esc */
2244
2245 if (user_msg == NULL)
2246 {
2247 s = expand_string(smtp_banner);
2248 if (s == NULL)
2249 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2250 "failed: %s", smtp_banner, expand_string_message);
2251 }
2252 else
2253 {
2254 int codelen = 3;
2255 s = user_msg;
2256 smtp_message_code(&code, &codelen, &s, NULL);
2257 if (codelen > 4)
2258 {
2259 esc = code + 4;
2260 esclen = codelen - 4;
2261 }
2262 }
2263
2264 /* Remove any terminating newlines; might as well remove trailing space too */
2265
2266 p = s + Ustrlen(s);
2267 while (p > s && isspace(p[-1])) p--;
2268 *p = 0;
2269
2270 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2271 is all contained in a single IP packet. The original code wrote out the
2272 greeting using several calls to fprint/fputc, and on busy servers this could
2273 cause it to be split over more than one packet - which caused CC:Mail to fall
2274 over when it got the second part of the greeting after sending its first
2275 command. Sigh. To try to avoid this, build the complete greeting message
2276 first, and output it in one fell swoop. This gives a better chance of it
2277 ending up as a single packet. */
2278
2279 ss = store_get(size);
2280 ptr = 0;
2281
2282 p = s;
2283 do /* At least once, in case we have an empty string */
2284 {
2285 int len;
2286 uschar *linebreak = Ustrchr(p, '\n');
2287 ss = string_cat(ss, &size, &ptr, code, 3);
2288 if (linebreak == NULL)
2289 {
2290 len = Ustrlen(p);
2291 ss = string_cat(ss, &size, &ptr, US" ", 1);
2292 }
2293 else
2294 {
2295 len = linebreak - p;
2296 ss = string_cat(ss, &size, &ptr, US"-", 1);
2297 }
2298 ss = string_cat(ss, &size, &ptr, esc, esclen);
2299 ss = string_cat(ss, &size, &ptr, p, len);
2300 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
2301 p += len;
2302 if (linebreak != NULL) p++;
2303 }
2304 while (*p != 0);
2305
2306 ss[ptr] = 0; /* string_cat leaves room for this */
2307
2308 /* Before we write the banner, check that there is no input pending, unless
2309 this synchronisation check is disabled. */
2310
2311 if (!check_sync())
2312 {
2313 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2314 "synchronization error (input sent without waiting for greeting): "
2315 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2316 string_printing(smtp_inptr));
2317 smtp_printf("554 SMTP synchronization error\r\n");
2318 return FALSE;
2319 }
2320
2321 /* Now output the banner */
2322
2323 smtp_printf("%s", ss);
2324 return TRUE;
2325 }
2326
2327
2328
2329
2330
2331 /*************************************************
2332 * Handle SMTP syntax and protocol errors *
2333 *************************************************/
2334
2335 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2336 to do so. Then transmit the error response. The return value depends on the
2337 number of syntax and protocol errors in this SMTP session.
2338
2339 Arguments:
2340 type error type, given as a log flag bit
2341 code response code; <= 0 means don't send a response
2342 data data to reflect in the response (can be NULL)
2343 errmess the error message
2344
2345 Returns: -1 limit of syntax/protocol errors NOT exceeded
2346 +1 limit of syntax/protocol errors IS exceeded
2347
2348 These values fit in with the values of the "done" variable in the main
2349 processing loop in smtp_setup_msg(). */
2350
2351 static int
2352 synprot_error(int type, int code, uschar *data, uschar *errmess)
2353 {
2354 int yield = -1;
2355
2356 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2357 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2358 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2359
2360 if (++synprot_error_count > smtp_max_synprot_errors)
2361 {
2362 yield = 1;
2363 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2364 "syntax or protocol errors (last command was \"%s\")",
2365 host_and_ident(FALSE), smtp_cmd_buffer);
2366 }
2367
2368 if (code > 0)
2369 {
2370 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2371 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2372 if (yield == 1)
2373 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2374 }
2375
2376 return yield;
2377 }
2378
2379
2380
2381
2382 /*************************************************
2383 * Log incomplete transactions *
2384 *************************************************/
2385
2386 /* This function is called after a transaction has been aborted by RSET, QUIT,
2387 connection drops or other errors. It logs the envelope information received
2388 so far in order to preserve address verification attempts.
2389
2390 Argument: string to indicate what aborted the transaction
2391 Returns: nothing
2392 */
2393
2394 static void
2395 incomplete_transaction_log(uschar *what)
2396 {
2397 if (sender_address == NULL || /* No transaction in progress */
2398 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
2399 ) return;
2400
2401 /* Build list of recipients for logging */
2402
2403 if (recipients_count > 0)
2404 {
2405 int i;
2406 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2407 for (i = 0; i < recipients_count; i++)
2408 raw_recipients[i] = recipients_list[i].address;
2409 raw_recipients_count = recipients_count;
2410 }
2411
2412 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2413 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2414 }
2415
2416
2417
2418
2419 /*************************************************
2420 * Send SMTP response, possibly multiline *
2421 *************************************************/
2422
2423 /* There are, it seems, broken clients out there that cannot handle multiline
2424 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2425 output nothing for non-final calls, and only the first line for anything else.
2426
2427 Arguments:
2428 code SMTP code, may involve extended status codes
2429 codelen length of smtp code; if > 4 there's an ESC
2430 final FALSE if the last line isn't the final line
2431 msg message text, possibly containing newlines
2432
2433 Returns: nothing
2434 */
2435
2436 void
2437 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2438 {
2439 int esclen = 0;
2440 uschar *esc = US"";
2441
2442 if (!final && no_multiline_responses) return;
2443
2444 if (codelen > 4)
2445 {
2446 esc = code + 4;
2447 esclen = codelen - 4;
2448 }
2449
2450 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2451 have had the same. Note: this code is also present in smtp_printf(). It would
2452 be tidier to have it only in one place, but when it was added, it was easier to
2453 do it that way, so as not to have to mess with the code for the RCPT command,
2454 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2455
2456 if (rcpt_in_progress)
2457 {
2458 if (rcpt_smtp_response == NULL)
2459 rcpt_smtp_response = string_copy(msg);
2460 else if (rcpt_smtp_response_same &&
2461 Ustrcmp(rcpt_smtp_response, msg) != 0)
2462 rcpt_smtp_response_same = FALSE;
2463 rcpt_in_progress = FALSE;
2464 }
2465
2466 /* Not output the message, splitting it up into multiple lines if necessary. */
2467
2468 for (;;)
2469 {
2470 uschar *nl = Ustrchr(msg, '\n');
2471 if (nl == NULL)
2472 {
2473 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2474 return;
2475 }
2476 else if (nl[1] == 0 || no_multiline_responses)
2477 {
2478 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2479 (int)(nl - msg), msg);
2480 return;
2481 }
2482 else
2483 {
2484 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2485 msg = nl + 1;
2486 while (isspace(*msg)) msg++;
2487 }
2488 }
2489 }
2490
2491
2492
2493
2494 /*************************************************
2495 * Parse user SMTP message *
2496 *************************************************/
2497
2498 /* This function allows for user messages overriding the response code details
2499 by providing a suitable response code string at the start of the message
2500 user_msg. Check the message for starting with a response code and optionally an
2501 extended status code. If found, check that the first digit is valid, and if so,
2502 change the code pointer and length to use the replacement. An invalid code
2503 causes a panic log; in this case, if the log messages is the same as the user
2504 message, we must also adjust the value of the log message to show the code that
2505 is actually going to be used (the original one).
2506
2507 This function is global because it is called from receive.c as well as within
2508 this module.
2509
2510 Note that the code length returned includes the terminating whitespace
2511 character, which is always included in the regex match.
2512
2513 Arguments:
2514 code SMTP code, may involve extended status codes
2515 codelen length of smtp code; if > 4 there's an ESC
2516 msg message text
2517 log_msg optional log message, to be adjusted with the new SMTP code
2518
2519 Returns: nothing
2520 */
2521
2522 void
2523 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2524 {
2525 int n;
2526 int ovector[3];
2527
2528 if (msg == NULL || *msg == NULL) return;
2529
2530 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2531 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2532 if (n < 0) return;
2533
2534 if ((*msg)[0] != (*code)[0])
2535 {
2536 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2537 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2538 if (log_msg != NULL && *log_msg == *msg)
2539 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2540 }
2541 else
2542 {
2543 *code = *msg;
2544 *codelen = ovector[1]; /* Includes final space */
2545 }
2546 *msg += ovector[1]; /* Chop the code off the message */
2547 return;
2548 }
2549
2550
2551
2552
2553 /*************************************************
2554 * Handle an ACL failure *
2555 *************************************************/
2556
2557 /* This function is called when acl_check() fails. As well as calls from within
2558 this module, it is called from receive.c for an ACL after DATA. It sorts out
2559 logging the incident, and sets up the error response. A message containing
2560 newlines is turned into a multiline SMTP response, but for logging, only the
2561 first line is used.
2562
2563 There's a table of default permanent failure response codes to use in
2564 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2565 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2566 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2567 state, because there are broken clients that try VRFY before RCPT. A 5xx
2568 response should be given only when the address is positively known to be
2569 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2570 503.
2571
2572 From Exim 4.63, it is possible to override the response code details by
2573 providing a suitable response code string at the start of the message provided
2574 in user_msg. The code's first digit is checked for validity.
2575
2576 Arguments:
2577 where where the ACL was called from
2578 rc the failure code
2579 user_msg a message that can be included in an SMTP response
2580 log_msg a message for logging
2581
2582 Returns: 0 in most cases
2583 2 if the failure code was FAIL_DROP, in which case the
2584 SMTP connection should be dropped (this value fits with the
2585 "done" variable in smtp_setup_msg() below)
2586 */
2587
2588 int
2589 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2590 {
2591 BOOL drop = rc == FAIL_DROP;
2592 int codelen = 3;
2593 uschar *smtp_code;
2594 uschar *lognl;
2595 uschar *sender_info = US"";
2596 uschar *what =
2597 #ifdef WITH_CONTENT_SCAN
2598 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2599 #endif
2600 (where == ACL_WHERE_PREDATA)? US"DATA" :
2601 (where == ACL_WHERE_DATA)? US"after DATA" :
2602 #ifdef EXPERIMENTAL_PRDR
2603 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2604 #endif
2605 (smtp_cmd_data == NULL)?
2606 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2607 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2608
2609 if (drop) rc = FAIL;
2610
2611 /* Set the default SMTP code, and allow a user message to change it. */
2612
2613 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2614 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2615
2616 /* We used to have sender_address here; however, there was a bug that was not
2617 updating sender_address after a rewrite during a verify. When this bug was
2618 fixed, sender_address at this point became the rewritten address. I'm not sure
2619 this is what should be logged, so I've changed to logging the unrewritten
2620 address to retain backward compatibility. */
2621
2622 #ifndef WITH_CONTENT_SCAN
2623 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2624 #else
2625 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2626 #endif
2627 {
2628 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2629 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2630 sender_host_authenticated ? US" A=" : US"",
2631 sender_host_authenticated ? sender_host_authenticated : US"",
2632 sender_host_authenticated && authenticated_id ? US":" : US"",
2633 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2634 );
2635 }
2636
2637 /* If there's been a sender verification failure with a specific message, and
2638 we have not sent a response about it yet, do so now, as a preliminary line for
2639 failures, but not defers. However, always log it for defer, and log it for fail
2640 unless the sender_verify_fail log selector has been turned off. */
2641
2642 if (sender_verified_failed != NULL &&
2643 !testflag(sender_verified_failed, af_sverify_told))
2644 {
2645 BOOL save_rcpt_in_progress = rcpt_in_progress;
2646 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2647
2648 setflag(sender_verified_failed, af_sverify_told);
2649
2650 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2651 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2652 host_and_ident(TRUE),
2653 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2654 sender_verified_failed->address,
2655 (sender_verified_failed->message == NULL)? US"" :
2656 string_sprintf(": %s", sender_verified_failed->message));
2657
2658 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2659 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2660 testflag(sender_verified_failed, af_verify_pmfail)?
2661 "Postmaster verification failed while checking <%s>\n%s\n"
2662 "Several RFCs state that you are required to have a postmaster\n"
2663 "mailbox for each mail domain. This host does not accept mail\n"
2664 "from domains whose servers reject the postmaster address."
2665 :
2666 testflag(sender_verified_failed, af_verify_nsfail)?
2667 "Callback setup failed while verifying <%s>\n%s\n"
2668 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2669 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2670 "RFC requirements, and stops you from receiving standard bounce\n"
2671 "messages. This host does not accept mail from domains whose servers\n"
2672 "refuse bounces."
2673 :
2674 "Verification failed for <%s>\n%s",
2675 sender_verified_failed->address,
2676 sender_verified_failed->user_message));
2677
2678 rcpt_in_progress = save_rcpt_in_progress;
2679 }
2680
2681 /* Sort out text for logging */
2682
2683 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2684 lognl = Ustrchr(log_msg, '\n');
2685 if (lognl != NULL) *lognl = 0;
2686
2687 /* Send permanent failure response to the command, but the code used isn't
2688 always a 5xx one - see comments at the start of this function. If the original
2689 rc was FAIL_DROP we drop the connection and yield 2. */
2690
2691 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2692 US"Administrative prohibition" : user_msg);
2693
2694 /* Send temporary failure response to the command. Don't give any details,
2695 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2696 verb, and for a header verify when smtp_return_error_details is set.
2697
2698 This conditional logic is all somewhat of a mess because of the odd
2699 interactions between temp_details and return_error_details. One day it should
2700 be re-implemented in a tidier fashion. */
2701
2702 else
2703 {
2704 if (acl_temp_details && user_msg != NULL)
2705 {
2706 if (smtp_return_error_details &&
2707 sender_verified_failed != NULL &&
2708 sender_verified_failed->message != NULL)
2709 {
2710 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2711 }
2712 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2713 }
2714 else
2715 smtp_respond(smtp_code, codelen, TRUE,
2716 US"Temporary local problem - please try later");
2717 }
2718
2719 /* Log the incident to the logs that are specified by log_reject_target
2720 (default main, reject). This can be empty to suppress logging of rejections. If
2721 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2722 is closing if required and return 2. */
2723
2724 if (log_reject_target != 0)
2725 {
2726 #ifdef SUPPORT_TLS
2727 uschar * s = s_tlslog(NULL, NULL, NULL);
2728 if (!s) s = US"";
2729 #else
2730 uschar * s = US"";
2731 #endif
2732 log_write(0, log_reject_target, "%s%s %s%srejected %s%s",
2733 host_and_ident(TRUE), s,
2734 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2735 }
2736
2737 if (!drop) return 0;
2738
2739 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2740 smtp_get_connection_info());
2741
2742 /* Run the not-quit ACL, but without any custom messages. This should not be a
2743 problem, because we get here only if some other ACL has issued "drop", and
2744 in that case, *its* custom messages will have been used above. */
2745
2746 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2747 return 2;
2748 }
2749
2750
2751
2752
2753 /*************************************************
2754 * Handle SMTP exit when QUIT is not given *
2755 *************************************************/
2756
2757 /* This function provides a logging/statistics hook for when an SMTP connection
2758 is dropped on the floor or the other end goes away. It's a global function
2759 because it's called from receive.c as well as this module. As well as running
2760 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2761 response, either with a custom message from the ACL, or using a default. There
2762 is one case, however, when no message is output - after "drop". In that case,
2763 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2764 passed to this function.
2765
2766 In case things go wrong while processing this function, causing an error that
2767 may re-enter this funtion, there is a recursion check.
2768
2769 Arguments:
2770 reason What $smtp_notquit_reason will be set to in the ACL;
2771 if NULL, the ACL is not run
2772 code The error code to return as part of the response
2773 defaultrespond The default message if there's no user_msg
2774
2775 Returns: Nothing
2776 */
2777
2778 void
2779 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2780 {
2781 int rc;
2782 uschar *user_msg = NULL;
2783 uschar *log_msg = NULL;
2784
2785 /* Check for recursive acll */
2786
2787 if (smtp_exit_function_called)
2788 {
2789 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2790 reason);
2791 return;
2792 }
2793 smtp_exit_function_called = TRUE;
2794
2795 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2796
2797 if (acl_smtp_notquit != NULL && reason != NULL)
2798 {
2799 smtp_notquit_reason = reason;
2800 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2801 &log_msg);
2802 if (rc == ERROR)
2803 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2804 log_msg);
2805 }
2806
2807 /* Write an SMTP response if we are expected to give one. As the default
2808 responses are all internal, they should always fit in the buffer, but code a
2809 warning, just in case. Note that string_vformat() still leaves a complete
2810 string, even if it is incomplete. */
2811
2812 if (code != NULL && defaultrespond != NULL)
2813 {
2814 if (user_msg == NULL)
2815 {
2816 uschar buffer[128];
2817 va_list ap;
2818 va_start(ap, defaultrespond);
2819 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2820 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2821 smtp_printf("%s %s\r\n", code, buffer);
2822 va_end(ap);
2823 }
2824 else
2825 smtp_respond(code, 3, TRUE, user_msg);
2826 mac_smtp_fflush();
2827 }
2828 }
2829
2830
2831
2832
2833 /*************************************************
2834 * Verify HELO argument *
2835 *************************************************/
2836
2837 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2838 matched. It is also called from ACL processing if verify = helo is used and
2839 verification was not previously tried (i.e. helo_try_verify_hosts was not
2840 matched). The result of its processing is to set helo_verified and
2841 helo_verify_failed. These variables should both be FALSE for this function to
2842 be called.
2843
2844 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2845 for IPv6 ::ffff: literals.
2846
2847 Argument: none
2848 Returns: TRUE if testing was completed;
2849 FALSE on a temporary failure
2850 */
2851
2852 BOOL
2853 smtp_verify_helo(void)
2854 {
2855 BOOL yield = TRUE;
2856
2857 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2858 sender_helo_name);
2859
2860 if (sender_helo_name == NULL)
2861 {
2862 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2863 }
2864
2865 /* Deal with the case of -bs without an IP address */
2866
2867 else if (sender_host_address == NULL)
2868 {
2869 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2870 helo_verified = TRUE;
2871 }
2872
2873 /* Deal with the more common case when there is a sending IP address */
2874
2875 else if (sender_helo_name[0] == '[')
2876 {
2877 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2878 Ustrlen(sender_host_address)) == 0;
2879
2880 #if HAVE_IPV6
2881 if (!helo_verified)
2882 {
2883 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2884 helo_verified = Ustrncmp(sender_helo_name + 1,
2885 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2886 }
2887 #endif
2888
2889 HDEBUG(D_receive)
2890 { if (helo_verified) debug_printf("matched host address\n"); }
2891 }
2892
2893 /* Do a reverse lookup if one hasn't already given a positive or negative
2894 response. If that fails, or the name doesn't match, try checking with a forward
2895 lookup. */
2896
2897 else
2898 {
2899 if (sender_host_name == NULL && !host_lookup_failed)
2900 yield = host_name_lookup() != DEFER;
2901
2902 /* If a host name is known, check it and all its aliases. */
2903
2904 if (sender_host_name != NULL)
2905 {
2906 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2907
2908 if (helo_verified)
2909 {
2910 HDEBUG(D_receive) debug_printf("matched host name\n");
2911 }
2912 else
2913 {
2914 uschar **aliases = sender_host_aliases;
2915 while (*aliases != NULL)
2916 {
2917 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2918 if (helo_verified) break;
2919 }
2920 HDEBUG(D_receive)
2921 {
2922 if (helo_verified)
2923 debug_printf("matched alias %s\n", *(--aliases));
2924 }
2925 }
2926 }
2927
2928 /* Final attempt: try a forward lookup of the helo name */
2929
2930 if (!helo_verified)
2931 {
2932 int rc;
2933 host_item h;
2934 h.name = sender_helo_name;
2935 h.address = NULL;
2936 h.mx = MX_NONE;
2937 h.next = NULL;
2938 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2939 sender_helo_name);
2940 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2941 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2942 {
2943 host_item *hh = &h;
2944 while (hh != NULL)
2945 {
2946 if (Ustrcmp(hh->address, sender_host_address) == 0)
2947 {
2948 helo_verified = TRUE;
2949 HDEBUG(D_receive)
2950 debug_printf("IP address for %s matches calling address\n",
2951 sender_helo_name);
2952 break;
2953 }
2954 hh = hh->next;
2955 }
2956 }
2957 }
2958 }
2959
2960 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2961 return yield;
2962 }
2963
2964
2965
2966
2967 /*************************************************
2968 * Send user response message *
2969 *************************************************/
2970
2971 /* This function is passed a default response code and a user message. It calls
2972 smtp_message_code() to check and possibly modify the response code, and then
2973 calls smtp_respond() to transmit the response. I put this into a function
2974 just to avoid a lot of repetition.
2975
2976 Arguments:
2977 code the response code
2978 user_msg the user message
2979
2980 Returns: nothing
2981 */
2982
2983 static void
2984 smtp_user_msg(uschar *code, uschar *user_msg)
2985 {
2986 int len = 3;
2987 smtp_message_code(&code, &len, &user_msg, NULL);
2988 smtp_respond(code, len, TRUE, user_msg);
2989 }
2990
2991
2992
2993 /*************************************************
2994 * Initialize for SMTP incoming message *
2995 *************************************************/
2996
2997 /* This function conducts the initial dialogue at the start of an incoming SMTP
2998 message, and builds a list of recipients. However, if the incoming message
2999 is part of a batch (-bS option) a separate function is called since it would
3000 be messy having tests splattered about all over this function. This function
3001 therefore handles the case where interaction is occurring. The input and output
3002 files are set up in smtp_in and smtp_out.
3003
3004 The global recipients_list is set to point to a vector of recipient_item
3005 blocks, whose number is given by recipients_count. This is extended by the
3006 receive_add_recipient() function. The global variable sender_address is set to
3007 the sender's address. The yield is +1 if a message has been successfully
3008 started, 0 if a QUIT command was encountered or the connection was refused from
3009 the particular host, or -1 if the connection was lost.
3010
3011 Argument: none
3012
3013 Returns: > 0 message successfully started (reached DATA)
3014 = 0 QUIT read or end of file reached or call refused
3015 < 0 lost connection
3016 */
3017
3018 int
3019 smtp_setup_msg(void)
3020 {
3021 int done = 0;
3022 BOOL toomany = FALSE;
3023 BOOL discarded = FALSE;
3024 BOOL last_was_rej_mail = FALSE;
3025 BOOL last_was_rcpt = FALSE;
3026 void *reset_point = store_get(0);
3027
3028 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3029
3030 /* Reset for start of new message. We allow one RSET not to be counted as a
3031 nonmail command, for those MTAs that insist on sending it between every
3032 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3033 TLS between messages (an Exim client may do this if it has messages queued up
3034 for the host). Note: we do NOT reset AUTH at this point. */
3035
3036 smtp_reset(reset_point);
3037 message_ended = END_NOTSTARTED;
3038
3039 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3040 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3041 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3042 #ifdef SUPPORT_TLS
3043 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3044 #endif
3045
3046 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3047
3048 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3049
3050 /* Batched SMTP is handled in a different function. */
3051
3052 if (smtp_batched_input) return smtp_setup_batch_msg();
3053
3054 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3055 value. The values are 2 larger than the required yield of the function. */
3056
3057 while (done <= 0)
3058 {
3059 uschar **argv;
3060 uschar *etrn_command;
3061 uschar *etrn_serialize_key;
3062 uschar *errmess;
3063 uschar *log_msg, *smtp_code;
3064 uschar *user_msg = NULL;
3065 uschar *recipient = NULL;
3066 uschar *hello = NULL;
3067 uschar *set_id = NULL;
3068 uschar *s, *ss;
3069 BOOL was_rej_mail = FALSE;
3070 BOOL was_rcpt = FALSE;
3071 void (*oldsignal)(int);
3072 pid_t pid;
3073 int start, end, sender_domain, recipient_domain;
3074 int ptr, size, rc;
3075 int c, i;
3076 auth_instance *au;
3077
3078 switch(smtp_read_command(TRUE))
3079 {
3080 /* The AUTH command is not permitted to occur inside a transaction, and may
3081 occur successfully only once per connection. Actually, that isn't quite
3082 true. When TLS is started, all previous information about a connection must
3083 be discarded, so a new AUTH is permitted at that time.
3084
3085 AUTH may only be used when it has been advertised. However, it seems that
3086 there are clients that send AUTH when it hasn't been advertised, some of
3087 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3088 So there's a get-out that allows this to happen.
3089
3090 AUTH is initially labelled as a "nonmail command" so that one occurrence
3091 doesn't get counted. We change the label here so that multiple failing
3092 AUTHS will eventually hit the nonmail threshold. */
3093
3094 case AUTH_CMD:
3095 HAD(SCH_AUTH);
3096 authentication_failed = TRUE;
3097 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3098
3099 if (!auth_advertised && !allow_auth_unadvertised)
3100 {
3101 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3102 US"AUTH command used when not advertised");
3103 break;
3104 }
3105 if (sender_host_authenticated != NULL)
3106 {
3107 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3108 US"already authenticated");
3109 break;
3110 }
3111 if (sender_address != NULL)
3112 {
3113 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3114 US"not permitted in mail transaction");
3115 break;
3116 }
3117
3118 /* Check the ACL */
3119
3120 if (acl_smtp_auth != NULL)
3121 {
3122 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
3123 if (rc != OK)
3124 {
3125 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3126 break;
3127 }
3128 }
3129
3130 /* Find the name of the requested authentication mechanism. */
3131
3132 s = smtp_cmd_data;
3133 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3134 {
3135 if (!isalnum(c) && c != '-' && c != '_')
3136 {
3137 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3138 US"invalid character in authentication mechanism name");
3139 goto COMMAND_LOOP;
3140 }
3141 smtp_cmd_data++;
3142 }
3143
3144 /* If not at the end of the line, we must be at white space. Terminate the
3145 name and move the pointer on to any data that may be present. */
3146
3147 if (*smtp_cmd_data != 0)
3148 {
3149 *smtp_cmd_data++ = 0;
3150 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3151 }
3152
3153 /* Search for an authentication mechanism which is configured for use
3154 as a server and which has been advertised (unless, sigh, allow_auth_
3155 unadvertised is set). */
3156
3157 for (au = auths; au != NULL; au = au->next)
3158 {
3159 if (strcmpic(s, au->public_name) == 0 && au->server &&
3160 (au->advertised || allow_auth_unadvertised)) break;
3161 }
3162
3163 if (au == NULL)
3164 {
3165 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3166 string_sprintf("%s authentication mechanism not supported", s));
3167 break;
3168 }
3169
3170 /* Run the checking code, passing the remainder of the command line as
3171 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3172 it as the only set numerical variable. The authenticator may set $auth<n>
3173 and also set other numeric variables. The $auth<n> variables are preferred
3174 nowadays; the numerical variables remain for backwards compatibility.
3175
3176 Afterwards, have a go at expanding the set_id string, even if
3177 authentication failed - for bad passwords it can be useful to log the
3178 userid. On success, require set_id to expand and exist, and put it in
3179 authenticated_id. Save this in permanent store, as the working store gets
3180 reset at HELO, RSET, etc. */
3181
3182 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3183 expand_nmax = 0;
3184 expand_nlength[0] = 0; /* $0 contains nothing */
3185
3186 c = (au->info->servercode)(au, smtp_cmd_data);
3187 if (au->set_id != NULL) set_id = expand_string(au->set_id);
3188 expand_nmax = -1; /* Reset numeric variables */
3189 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3190
3191 /* The value of authenticated_id is stored in the spool file and printed in
3192 log lines. It must not contain binary zeros or newline characters. In
3193 normal use, it never will, but when playing around or testing, this error
3194 can (did) happen. To guard against this, ensure that the id contains only
3195 printing characters. */
3196
3197 if (set_id != NULL) set_id = string_printing(set_id);
3198
3199 /* For the non-OK cases, set up additional logging data if set_id
3200 is not empty. */
3201
3202 if (c != OK)
3203 {
3204 if (set_id != NULL && *set_id != 0)
3205 set_id = string_sprintf(" (set_id=%s)", set_id);
3206 else set_id = US"";
3207 }
3208
3209 /* Switch on the result */
3210
3211 switch(c)
3212 {
3213 case OK:
3214 if (au->set_id == NULL || set_id != NULL) /* Complete success */
3215 {
3216 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
3217 sender_host_authenticated = au->name;
3218 authentication_failed = FALSE;
3219 authenticated_fail_id = NULL; /* Impossible to already be set? */
3220 received_protocol =
3221 protocols[pextend + pauthed + ((tls_in.active >= 0)? pcrpted:0)] +
3222 ((sender_host_address != NULL)? pnlocal : 0);
3223 s = ss = US"235 Authentication succeeded";
3224 authenticated_by = au;
3225 break;
3226 }
3227
3228 /* Authentication succeeded, but we failed to expand the set_id string.
3229 Treat this as a temporary error. */
3230
3231 auth_defer_msg = expand_string_message;
3232 /* Fall through */
3233
3234 case DEFER:
3235 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3236 s = string_sprintf("435 Unable to authenticate at present%s",
3237 auth_defer_user_msg);
3238 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3239 set_id, auth_defer_msg);
3240 break;
3241
3242 case BAD64:
3243 s = ss = US"501 Invalid base64 data";
3244 break;
3245
3246 case CANCELLED:
3247 s = ss = US"501 Authentication cancelled";
3248 break;
3249
3250 case UNEXPECTED:
3251 s = ss = US"553 Initial data not expected";
3252 break;
3253
3254 case FAIL:
3255 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3256 s = US"535 Incorrect authentication data";
3257 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3258 break;
3259
3260 default:
3261 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3262 s = US"435 Internal error";
3263 ss = string_sprintf("435 Internal error%s: return %d from authentication "
3264 "check", set_id, c);
3265 break;
3266 }
3267
3268 smtp_printf("%s\r\n", s);
3269 if (c != OK)
3270 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3271 au->name, host_and_ident(FALSE), ss);
3272
3273 break; /* AUTH_CMD */
3274
3275 /* The HELO/EHLO commands are permitted to appear in the middle of a
3276 session as well as at the beginning. They have the effect of a reset in
3277 addition to their other functions. Their absence at the start cannot be
3278 taken to be an error.
3279
3280 RFC 2821 says:
3281
3282 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3283 or 502 failure replies MUST be returned as appropriate. The SMTP
3284 server MUST stay in the same state after transmitting these replies
3285 that it was in before the EHLO was received.
3286
3287 Therefore, we do not do the reset until after checking the command for
3288 acceptability. This change was made for Exim release 4.11. Previously
3289 it did the reset first. */
3290
3291 case HELO_CMD:
3292 HAD(SCH_HELO);
3293 hello = US"HELO";
3294 esmtp = FALSE;
3295 goto HELO_EHLO;
3296
3297 case EHLO_CMD:
3298 HAD(SCH_EHLO);
3299 hello = US"EHLO";
3300 esmtp = TRUE;
3301
3302 HELO_EHLO: /* Common code for HELO and EHLO */
3303 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3304 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3305
3306 /* Reject the HELO if its argument was invalid or non-existent. A
3307 successful check causes the argument to be saved in malloc store. */
3308
3309 if (!check_helo(smtp_cmd_data))
3310 {
3311 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3312
3313 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3314 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3315 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3316 string_printing(smtp_cmd_argument));
3317
3318 if (++synprot_error_count > smtp_max_synprot_errors)
3319 {
3320 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3321 "syntax or protocol errors (last command was \"%s\")",
3322 host_and_ident(FALSE), smtp_cmd_buffer);
3323 done = 1;
3324 }
3325
3326 break;
3327 }
3328
3329 /* If sender_host_unknown is true, we have got here via the -bs interface,
3330 not called from inetd. Otherwise, we are running an IP connection and the
3331 host address will be set. If the helo name is the primary name of this
3332 host and we haven't done a reverse lookup, force one now. If helo_required
3333 is set, ensure that the HELO name matches the actual host. If helo_verify
3334 is set, do the same check, but softly. */
3335
3336 if (!sender_host_unknown)
3337 {
3338 BOOL old_helo_verified = helo_verified;
3339 uschar *p = smtp_cmd_data;
3340
3341 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3342 *p = 0;
3343
3344 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3345 because otherwise the log can be confusing. */
3346
3347 if (sender_host_name == NULL &&
3348 (deliver_domain = sender_helo_name, /* set $domain */
3349 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
3350 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3351 (void)host_name_lookup();
3352
3353 /* Rebuild the fullhost info to include the HELO name (and the real name
3354 if it was looked up.) */
3355
3356 host_build_sender_fullhost(); /* Rebuild */
3357 set_process_info("handling%s incoming connection from %s",
3358 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3359
3360 /* Verify if configured. This doesn't give much security, but it does
3361 make some people happy to be able to do it. If helo_required is set,
3362 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3363 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3364 now obsolescent, since the verification can now be requested selectively
3365 at ACL time. */
3366
3367 helo_verified = helo_verify_failed = FALSE;
3368 if (helo_required || helo_verify)
3369 {
3370 BOOL tempfail = !smtp_verify_helo();
3371 if (!helo_verified)
3372 {
3373 if (helo_required)
3374 {
3375 smtp_printf("%d %s argument does not match calling host\r\n",
3376 tempfail? 451 : 550, hello);
3377 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3378 tempfail? "temporarily " : "",
3379 hello, sender_helo_name, host_and_ident(FALSE));
3380 helo_verified = old_helo_verified;
3381 break; /* End of HELO/EHLO processing */
3382 }
3383 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3384 "helo_try_verify_hosts\n", hello);
3385 }
3386 }
3387 }
3388
3389 #ifdef EXPERIMENTAL_SPF
3390 /* set up SPF context */
3391 spf_init(sender_helo_name, sender_host_address);
3392 #endif
3393
3394 /* Apply an ACL check if one is defined; afterwards, recheck
3395 synchronization in case the client started sending in a delay. */
3396
3397 if (acl_smtp_helo != NULL)
3398 {
3399 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
3400 if (rc != OK)
3401 {
3402 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3403 sender_helo_name = NULL;
3404 host_build_sender_fullhost(); /* Rebuild */
3405 break;
3406 }
3407 else if (!check_sync()) goto SYNC_FAILURE;
3408 }
3409
3410 /* Generate an OK reply. The default string includes the ident if present,
3411 and also the IP address if present. Reflecting back the ident is intended
3412 as a deterrent to mail forgers. For maximum efficiency, and also because
3413 some broken systems expect each response to be in a single packet, arrange
3414 that the entire reply is sent in one write(). */
3415
3416 auth_advertised = FALSE;
3417 pipelining_advertised = FALSE;
3418 #ifdef SUPPORT_TLS
3419 tls_advertised = FALSE;
3420 #endif
3421
3422 smtp_code = US"250 "; /* Default response code plus space*/
3423 if (user_msg == NULL)
3424 {
3425 s = string_sprintf("%.3s %s Hello %s%s%s",
3426 smtp_code,
3427 smtp_active_hostname,
3428 (sender_ident == NULL)? US"" : sender_ident,
3429 (sender_ident == NULL)? US"" : US" at ",
3430 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3431
3432 ptr = Ustrlen(s);
3433 size = ptr + 1;
3434
3435 if (sender_host_address != NULL)
3436 {
3437 s = string_cat(s, &size, &ptr, US" [", 2);
3438 s = string_cat(s, &size, &ptr, sender_host_address,
3439 Ustrlen(sender_host_address));
3440 s = string_cat(s, &size, &ptr, US"]", 1);
3441 }
3442 }
3443
3444 /* A user-supplied EHLO greeting may not contain more than one line. Note
3445 that the code returned by smtp_message_code() includes the terminating
3446 whitespace character. */
3447
3448 else
3449 {
3450 char *ss;
3451 int codelen = 4;
3452 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3453 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3454 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3455 {
3456 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3457 "newlines: message truncated: %s", string_printing(s));
3458 *ss = 0;
3459 }
3460 ptr = Ustrlen(s);
3461 size = ptr + 1;
3462 }
3463
3464 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3465
3466 /* If we received EHLO, we must create a multiline response which includes
3467 the functions supported. */
3468
3469 if (esmtp)
3470 {
3471 s[3] = '-';
3472
3473 /* I'm not entirely happy with this, as an MTA is supposed to check
3474 that it has enough room to accept a message of maximum size before
3475 it sends this. However, there seems little point in not sending it.
3476 The actual size check happens later at MAIL FROM time. By postponing it
3477 till then, VRFY and EXPN can be used after EHLO when space is short. */
3478
3479 if (thismessage_size_limit > 0)
3480 {
3481 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3482 thismessage_size_limit);
3483 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3484 }
3485 else
3486 {
3487 s = string_cat(s, &size, &ptr, smtp_code, 3);
3488 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3489 }
3490
3491 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3492 clean; if it has an 8-bit character in its hand, it just sends it. It
3493 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3494 However, some users want this option simply in order to stop MUAs
3495 mangling messages that contain top-bit-set characters. It is therefore
3496 provided as an option. */
3497
3498 if (accept_8bitmime)
3499 {
3500 s = string_cat(s, &size, &ptr, smtp_code, 3);
3501 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3502 }
3503
3504 /* Advertise ETRN if there's an ACL checking whether a host is
3505 permitted to issue it; a check is made when any host actually tries. */
3506
3507 if (acl_smtp_etrn != NULL)
3508 {
3509 s = string_cat(s, &size, &ptr, smtp_code, 3);
3510 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3511 }
3512
3513 /* Advertise EXPN if there's an ACL checking whether a host is