4761220451193e09209a4c40f9961ffe20c52589
[exim.git] / src / src / smtp_in.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2015 */
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 TLS_AUTH_CMD, /* auto-command at start of SSL */
75
76 /* This is a dummy to identify the non-sync commands when pipelining */
77
78 NON_SYNC_CMD_PIPELINING,
79
80 /* These commands need not be synchronized when pipelining */
81
82 MAIL_CMD, RCPT_CMD, RSET_CMD,
83
84 /* This is a dummy to identify the non-sync commands when not pipelining */
85
86 NON_SYNC_CMD_NON_PIPELINING,
87
88 /* I have been unable to find a statement about the use of pipelining
89 with AUTH, so to be on the safe side it is here, though I kind of feel
90 it should be up there with the synchronized commands. */
91
92 AUTH_CMD,
93
94 /* I'm not sure about these, but I don't think they matter. */
95
96 QUIT_CMD, HELP_CMD,
97
98 #ifdef EXPERIMENTAL_PROXY
99 PROXY_FAIL_IGNORE_CMD,
100 #endif
101
102 /* These are specials that don't correspond to actual commands */
103
104 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
105 TOO_MANY_NONMAIL_CMD };
106
107
108 /* This is a convenience macro for adding the identity of an SMTP command
109 to the circular buffer that holds a list of the last n received. */
110
111 #define HAD(n) \
112 smtp_connection_had[smtp_ch_index++] = n; \
113 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
114
115
116 /*************************************************
117 * Local static variables *
118 *************************************************/
119
120 static auth_instance *authenticated_by;
121 static BOOL auth_advertised;
122 #ifdef SUPPORT_TLS
123 static BOOL tls_advertised;
124 #endif
125 static BOOL dsn_advertised;
126 static BOOL esmtp;
127 static BOOL helo_required = FALSE;
128 static BOOL helo_verify = FALSE;
129 static BOOL helo_seen;
130 static BOOL helo_accept_junk;
131 static BOOL count_nonmail;
132 static BOOL pipelining_advertised;
133 static BOOL rcpt_smtp_response_same;
134 static BOOL rcpt_in_progress;
135 static int nonmail_command_count;
136 static BOOL smtp_exit_function_called = 0;
137 #ifdef EXPERIMENTAL_INTERNATIONAL
138 static BOOL smtputf8_advertised;
139 #endif
140 static int synprot_error_count;
141 static int unknown_command_count;
142 static int sync_cmd_limit;
143 static int smtp_write_error = 0;
144
145 static uschar *rcpt_smtp_response;
146 static uschar *smtp_data_buffer;
147 static uschar *smtp_cmd_data;
148
149 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
150 final fields of all except AUTH are forced TRUE at the start of a new message
151 setup, to allow one of each between messages that is not counted as a nonmail
152 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
153 allow a new EHLO after starting up TLS.
154
155 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
156 counted. However, the flag is changed when AUTH is received, so that multiple
157 failing AUTHs will eventually hit the limit. After a successful AUTH, another
158 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
159 forced TRUE, to allow for the re-authentication that can happen at that point.
160
161 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
162 count of non-mail commands and possibly provoke an error. */
163
164 static smtp_cmd_list cmd_list[] = {
165 /* name len cmd has_arg is_mail_cmd */
166
167 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
168 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
169 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
170 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
171 #ifdef SUPPORT_TLS
172 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
173 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, TRUE },
174 #endif
175
176 /* If you change anything above here, also fix the definitions below. */
177
178 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
179 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
180 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
181 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
182 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
183 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
184 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
185 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
186 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
187 };
188
189 static smtp_cmd_list *cmd_list_end =
190 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
191
192 #define CMD_LIST_RSET 0
193 #define CMD_LIST_HELO 1
194 #define CMD_LIST_EHLO 2
195 #define CMD_LIST_AUTH 3
196 #define CMD_LIST_STARTTLS 4
197 #define CMD_LIST_TLS_AUTH 5
198
199 /* This list of names is used for performing the smtp_no_mail logging action.
200 It must be kept in step with the SCH_xxx enumerations. */
201
202 static uschar *smtp_names[] =
203 {
204 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
205 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
206 US"VRFY" };
207
208 static uschar *protocols_local[] = {
209 US"local-smtp", /* HELO */
210 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
211 US"local-esmtp", /* EHLO */
212 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
213 US"local-esmtpa", /* EHLO->AUTH */
214 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
215 };
216 static uschar *protocols[] = {
217 US"smtp", /* HELO */
218 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
219 US"esmtp", /* EHLO */
220 US"esmtps", /* EHLO->STARTTLS->EHLO */
221 US"esmtpa", /* EHLO->AUTH */
222 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
223 };
224
225 #define pnormal 0
226 #define pextend 2
227 #define pcrpted 1 /* added to pextend or pnormal */
228 #define pauthed 2 /* added to pextend */
229
230 /* Sanity check and validate optional args to MAIL FROM: envelope */
231 enum {
232 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
233 #ifndef DISABLE_PRDR
234 ENV_MAIL_OPT_PRDR,
235 #endif
236 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
237 #ifdef EXPERIMENTAL_INTERNATIONAL
238 ENV_MAIL_OPT_UTF8,
239 #endif
240 ENV_MAIL_OPT_NULL
241 };
242 typedef struct {
243 uschar * name; /* option requested during MAIL cmd */
244 int value; /* enum type */
245 BOOL need_value; /* TRUE requires value (name=value pair format)
246 FALSE is a singleton */
247 } env_mail_type_t;
248 static env_mail_type_t env_mail_type_list[] = {
249 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
250 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
251 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
252 #ifndef DISABLE_PRDR
253 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
254 #endif
255 { US"RET", ENV_MAIL_OPT_RET, TRUE },
256 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
257 #ifdef EXPERIMENTAL_INTERNATIONAL
258 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
259 #endif
260 { US"NULL", ENV_MAIL_OPT_NULL, FALSE }
261 };
262
263 /* When reading SMTP from a remote host, we have to use our own versions of the
264 C input-reading functions, in order to be able to flush the SMTP output only
265 when about to read more data from the socket. This is the only way to get
266 optimal performance when the client is using pipelining. Flushing for every
267 command causes a separate packet and reply packet each time; saving all the
268 responses up (when pipelining) combines them into one packet and one response.
269
270 For simplicity, these functions are used for *all* SMTP input, not only when
271 receiving over a socket. However, after setting up a secure socket (SSL), input
272 is read via the OpenSSL library, and another set of functions is used instead
273 (see tls.c).
274
275 These functions are set in the receive_getc etc. variables and called with the
276 same interface as the C functions. However, since there can only ever be
277 one incoming SMTP call, we just use a single buffer and flags. There is no need
278 to implement a complicated private FILE-like structure.*/
279
280 static uschar *smtp_inbuffer;
281 static uschar *smtp_inptr;
282 static uschar *smtp_inend;
283 static int smtp_had_eof;
284 static int smtp_had_error;
285
286
287 /*************************************************
288 * SMTP version of getc() *
289 *************************************************/
290
291 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
292 it flushes the output, and refills the buffer, with a timeout. The signal
293 handler is set appropriately by the calling function. This function is not used
294 after a connection has negotated itself into an TLS/SSL state.
295
296 Arguments: none
297 Returns: the next character or EOF
298 */
299
300 int
301 smtp_getc(void)
302 {
303 if (smtp_inptr >= smtp_inend)
304 {
305 int rc, save_errno;
306 fflush(smtp_out);
307 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
308 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
309 save_errno = errno;
310 alarm(0);
311 if (rc <= 0)
312 {
313 /* Must put the error text in fixed store, because this might be during
314 header reading, where it releases unused store above the header. */
315 if (rc < 0)
316 {
317 smtp_had_error = save_errno;
318 smtp_read_error = string_copy_malloc(
319 string_sprintf(" (error: %s)", strerror(save_errno)));
320 }
321 else smtp_had_eof = 1;
322 return EOF;
323 }
324 #ifndef DISABLE_DKIM
325 dkim_exim_verify_feed(smtp_inbuffer, rc);
326 #endif
327 smtp_inend = smtp_inbuffer + rc;
328 smtp_inptr = smtp_inbuffer;
329 }
330 return *smtp_inptr++;
331 }
332
333
334
335 /*************************************************
336 * SMTP version of ungetc() *
337 *************************************************/
338
339 /* Puts a character back in the input buffer. Only ever
340 called once.
341
342 Arguments:
343 ch the character
344
345 Returns: the character
346 */
347
348 int
349 smtp_ungetc(int ch)
350 {
351 *(--smtp_inptr) = ch;
352 return ch;
353 }
354
355
356
357
358 /*************************************************
359 * SMTP version of feof() *
360 *************************************************/
361
362 /* Tests for a previous EOF
363
364 Arguments: none
365 Returns: non-zero if the eof flag is set
366 */
367
368 int
369 smtp_feof(void)
370 {
371 return smtp_had_eof;
372 }
373
374
375
376
377 /*************************************************
378 * SMTP version of ferror() *
379 *************************************************/
380
381 /* Tests for a previous read error, and returns with errno
382 restored to what it was when the error was detected.
383
384 Arguments: none
385 Returns: non-zero if the error flag is set
386 */
387
388 int
389 smtp_ferror(void)
390 {
391 errno = smtp_had_error;
392 return smtp_had_error;
393 }
394
395
396
397 /*************************************************
398 * Test for characters in the SMTP buffer *
399 *************************************************/
400
401 /* Used at the end of a message
402
403 Arguments: none
404 Returns: TRUE/FALSE
405 */
406
407 BOOL
408 smtp_buffered(void)
409 {
410 return smtp_inptr < smtp_inend;
411 }
412
413
414
415 /*************************************************
416 * Write formatted string to SMTP channel *
417 *************************************************/
418
419 /* This is a separate function so that we don't have to repeat everything for
420 TLS support or debugging. It is global so that the daemon and the
421 authentication functions can use it. It does not return any error indication,
422 because major problems such as dropped connections won't show up till an output
423 flush for non-TLS connections. The smtp_fflush() function is available for
424 checking that: for convenience, TLS output errors are remembered here so that
425 they are also picked up later by smtp_fflush().
426
427 Arguments:
428 format format string
429 ... optional arguments
430
431 Returns: nothing
432 */
433
434 void
435 smtp_printf(const char *format, ...)
436 {
437 va_list ap;
438
439 va_start(ap, format);
440 smtp_vprintf(format, ap);
441 va_end(ap);
442 }
443
444 /* This is split off so that verify.c:respond_printf() can, in effect, call
445 smtp_printf(), bearing in mind that in C a vararg function can't directly
446 call another vararg function, only a function which accepts a va_list. */
447
448 void
449 smtp_vprintf(const char *format, va_list ap)
450 {
451 BOOL yield;
452
453 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
454
455 DEBUG(D_receive)
456 {
457 void *reset_point = store_get(0);
458 uschar *msg_copy, *cr, *end;
459 msg_copy = string_copy(big_buffer);
460 end = msg_copy + Ustrlen(msg_copy);
461 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
462 memmove(cr, cr + 1, (end--) - cr);
463 debug_printf("SMTP>> %s", msg_copy);
464 store_reset(reset_point);
465 }
466
467 if (!yield)
468 {
469 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
470 smtp_closedown(US"Unexpected error");
471 exim_exit(EXIT_FAILURE);
472 }
473
474 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
475 have had the same. Note: this code is also present in smtp_respond(). It would
476 be tidier to have it only in one place, but when it was added, it was easier to
477 do it that way, so as not to have to mess with the code for the RCPT command,
478 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
479
480 if (rcpt_in_progress)
481 {
482 if (rcpt_smtp_response == NULL)
483 rcpt_smtp_response = string_copy(big_buffer);
484 else if (rcpt_smtp_response_same &&
485 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
486 rcpt_smtp_response_same = FALSE;
487 rcpt_in_progress = FALSE;
488 }
489
490 /* Now write the string */
491
492 #ifdef SUPPORT_TLS
493 if (tls_in.active >= 0)
494 {
495 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
496 smtp_write_error = -1;
497 }
498 else
499 #endif
500
501 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
502 }
503
504
505
506 /*************************************************
507 * Flush SMTP out and check for error *
508 *************************************************/
509
510 /* This function isn't currently used within Exim (it detects errors when it
511 tries to read the next SMTP input), but is available for use in local_scan().
512 For non-TLS connections, it flushes the output and checks for errors. For
513 TLS-connections, it checks for a previously-detected TLS write error.
514
515 Arguments: none
516 Returns: 0 for no error; -1 after an error
517 */
518
519 int
520 smtp_fflush(void)
521 {
522 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
523 return smtp_write_error;
524 }
525
526
527
528 /*************************************************
529 * SMTP command read timeout *
530 *************************************************/
531
532 /* Signal handler for timing out incoming SMTP commands. This attempts to
533 finish off tidily.
534
535 Argument: signal number (SIGALRM)
536 Returns: nothing
537 */
538
539 static void
540 command_timeout_handler(int sig)
541 {
542 sig = sig; /* Keep picky compilers happy */
543 log_write(L_lost_incoming_connection,
544 LOG_MAIN, "SMTP command timeout on%s connection from %s",
545 (tls_in.active >= 0)? " TLS" : "",
546 host_and_ident(FALSE));
547 if (smtp_batched_input)
548 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
549 smtp_notquit_exit(US"command-timeout", US"421",
550 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
551 exim_exit(EXIT_FAILURE);
552 }
553
554
555
556 /*************************************************
557 * SIGTERM received *
558 *************************************************/
559
560 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
561
562 Argument: signal number (SIGTERM)
563 Returns: nothing
564 */
565
566 static void
567 command_sigterm_handler(int sig)
568 {
569 sig = sig; /* Keep picky compilers happy */
570 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
571 if (smtp_batched_input)
572 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
573 smtp_notquit_exit(US"signal-exit", US"421",
574 US"%s: Service not available - closing connection", smtp_active_hostname);
575 exim_exit(EXIT_FAILURE);
576 }
577
578
579
580
581 #ifdef EXPERIMENTAL_PROXY
582 /*************************************************
583 * Restore socket timeout to previous value *
584 *************************************************/
585 /* If the previous value was successfully retrieved, restore
586 it before returning control to the non-proxy routines
587
588 Arguments: fd - File descriptor for input
589 get_ok - Successfully retrieved previous values
590 tvtmp - Time struct with previous values
591 vslen - Length of time struct
592 Returns: none
593 */
594 static void
595 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
596 {
597 if (get_ok == 0)
598 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
599 }
600
601 /*************************************************
602 * Check if host is required proxy host *
603 *************************************************/
604 /* The function determines if inbound host will be a regular smtp host
605 or if it is configured that it must use Proxy Protocol.
606
607 Arguments: none
608 Returns: bool
609 */
610
611 static BOOL
612 check_proxy_protocol_host()
613 {
614 int rc;
615 /* Cannot configure local connection as a proxy inbound */
616 if (sender_host_address == NULL) return proxy_session;
617
618 rc = verify_check_this_host(&proxy_required_hosts, NULL, NULL,
619 sender_host_address, NULL);
620 if (rc == OK)
621 {
622 DEBUG(D_receive)
623 debug_printf("Detected proxy protocol configured host\n");
624 proxy_session = TRUE;
625 }
626 return proxy_session;
627 }
628
629
630 /*************************************************
631 * Setup host for proxy protocol *
632 *************************************************/
633 /* The function configures the connection based on a header from the
634 inbound host to use Proxy Protocol. The specification is very exact
635 so exit with an error if do not find the exact required pieces. This
636 includes an incorrect number of spaces separating args.
637
638 Arguments: none
639 Returns: int
640 */
641
642 static BOOL
643 setup_proxy_protocol_host()
644 {
645 union {
646 struct {
647 uschar line[108];
648 } v1;
649 struct {
650 uschar sig[12];
651 uint8_t ver_cmd;
652 uint8_t fam;
653 uint16_t len;
654 union {
655 struct { /* TCP/UDP over IPv4, len = 12 */
656 uint32_t src_addr;
657 uint32_t dst_addr;
658 uint16_t src_port;
659 uint16_t dst_port;
660 } ip4;
661 struct { /* TCP/UDP over IPv6, len = 36 */
662 uint8_t src_addr[16];
663 uint8_t dst_addr[16];
664 uint16_t src_port;
665 uint16_t dst_port;
666 } ip6;
667 struct { /* AF_UNIX sockets, len = 216 */
668 uschar src_addr[108];
669 uschar dst_addr[108];
670 } unx;
671 } addr;
672 } v2;
673 } hdr;
674
675 /* Temp variables used in PPv2 address:port parsing */
676 uint16_t tmpport;
677 char tmpip[INET_ADDRSTRLEN];
678 struct sockaddr_in tmpaddr;
679 char tmpip6[INET6_ADDRSTRLEN];
680 struct sockaddr_in6 tmpaddr6;
681
682 int get_ok = 0;
683 int size, ret, fd;
684 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
685 uschar *iptype; /* To display debug info */
686 struct timeval tv;
687 socklen_t vslen = 0;
688 struct timeval tvtmp;
689
690 vslen = sizeof(struct timeval);
691
692 fd = fileno(smtp_in);
693
694 /* Save current socket timeout values */
695 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
696 &vslen);
697
698 /* Proxy Protocol host must send header within a short time
699 (default 3 seconds) or it's considered invalid */
700 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
701 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
702 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
703 sizeof(struct timeval));
704
705 do
706 {
707 /* The inbound host was declared to be a Proxy Protocol host, so
708 don't do a PEEK into the data, actually slurp it up. */
709 ret = recv(fd, &hdr, sizeof(hdr), 0);
710 }
711 while (ret == -1 && errno == EINTR);
712
713 if (ret == -1)
714 {
715 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
716 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
717 }
718
719 if (ret >= 16 &&
720 memcmp(&hdr.v2, v2sig, 12) == 0)
721 {
722 uint8_t ver, cmd;
723
724 /* May 2014: haproxy combined the version and command into one byte to
725 allow two full bytes for the length field in order to proxy SSL
726 connections. SSL Proxy is not supported in this version of Exim, but
727 must still seperate values here. */
728 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
729 cmd = (hdr.v2.ver_cmd & 0x0f);
730
731 if (ver != 0x02)
732 {
733 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
734 goto proxyfail;
735 }
736 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
737 /* The v2 header will always be 16 bytes per the spec. */
738 size = 16 + hdr.v2.len;
739 if (ret < size)
740 {
741 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
742 ret, size);
743 goto proxyfail;
744 }
745 switch (cmd)
746 {
747 case 0x01: /* PROXY command */
748 switch (hdr.v2.fam)
749 {
750 case 0x11: /* TCPv4 address type */
751 iptype = US"IPv4";
752 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
753 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
754 if (!string_is_ip_address(US tmpip,NULL))
755 {
756 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
757 return ERRNO_PROXYFAIL;
758 }
759 proxy_host_address = sender_host_address;
760 sender_host_address = string_copy(US tmpip);
761 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
762 proxy_host_port = sender_host_port;
763 sender_host_port = tmpport;
764 /* Save dest ip/port */
765 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
766 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
767 if (!string_is_ip_address(US tmpip,NULL))
768 {
769 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
770 return ERRNO_PROXYFAIL;
771 }
772 proxy_target_address = string_copy(US tmpip);
773 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
774 proxy_target_port = tmpport;
775 goto done;
776 case 0x21: /* TCPv6 address type */
777 iptype = US"IPv6";
778 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
779 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
780 if (!string_is_ip_address(US tmpip6,NULL))
781 {
782 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
783 return ERRNO_PROXYFAIL;
784 }
785 proxy_host_address = sender_host_address;
786 sender_host_address = string_copy(US tmpip6);
787 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
788 proxy_host_port = sender_host_port;
789 sender_host_port = tmpport;
790 /* Save dest ip/port */
791 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
792 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
793 if (!string_is_ip_address(US tmpip6,NULL))
794 {
795 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
796 return ERRNO_PROXYFAIL;
797 }
798 proxy_target_address = string_copy(US tmpip6);
799 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
800 proxy_target_port = tmpport;
801 goto done;
802 default:
803 DEBUG(D_receive)
804 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
805 hdr.v2.fam);
806 goto proxyfail;
807 }
808 /* Unsupported protocol, keep local connection address */
809 break;
810 case 0x00: /* LOCAL command */
811 /* Keep local connection address for LOCAL */
812 break;
813 default:
814 DEBUG(D_receive)
815 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
816 goto proxyfail;
817 }
818 }
819 else if (ret >= 8 &&
820 memcmp(hdr.v1.line, "PROXY", 5) == 0)
821 {
822 uschar *p = string_copy(hdr.v1.line);
823 uschar *end = memchr(p, '\r', ret - 1);
824 uschar *sp; /* Utility variables follow */
825 int tmp_port;
826 char *endc;
827
828 if (!end || end[1] != '\n')
829 {
830 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
831 goto proxyfail;
832 }
833 *end = '\0'; /* Terminate the string */
834 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
835 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
836 /* Step through the string looking for the required fields. Ensure
837 strict adherance to required formatting, exit for any error. */
838 p += 5;
839 if (!isspace(*(p++)))
840 {
841 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
842 goto proxyfail;
843 }
844 if (!Ustrncmp(p, CCS"TCP4", 4))
845 iptype = US"IPv4";
846 else if (!Ustrncmp(p,CCS"TCP6", 4))
847 iptype = US"IPv6";
848 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
849 {
850 iptype = US"Unknown";
851 goto done;
852 }
853 else
854 {
855 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
856 goto proxyfail;
857 }
858
859 p += Ustrlen(iptype);
860 if (!isspace(*(p++)))
861 {
862 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
863 goto proxyfail;
864 }
865 /* Find the end of the arg */
866 if ((sp = Ustrchr(p, ' ')) == NULL)
867 {
868 DEBUG(D_receive)
869 debug_printf("Did not find proxied src %s\n", iptype);
870 goto proxyfail;
871 }
872 *sp = '\0';
873 if(!string_is_ip_address(p,NULL))
874 {
875 DEBUG(D_receive)
876 debug_printf("Proxied src arg is not an %s address\n", iptype);
877 goto proxyfail;
878 }
879 proxy_host_address = sender_host_address;
880 sender_host_address = p;
881 p = sp + 1;
882 if ((sp = Ustrchr(p, ' ')) == NULL)
883 {
884 DEBUG(D_receive)
885 debug_printf("Did not find proxy dest %s\n", iptype);
886 goto proxyfail;
887 }
888 *sp = '\0';
889 if(!string_is_ip_address(p,NULL))
890 {
891 DEBUG(D_receive)
892 debug_printf("Proxy dest arg is not an %s address\n", iptype);
893 goto proxyfail;
894 }
895 proxy_target_address = p;
896 p = sp + 1;
897 if ((sp = Ustrchr(p, ' ')) == NULL)
898 {
899 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
900 goto proxyfail;
901 }
902 *sp = '\0';
903 tmp_port = strtol(CCS p,&endc,10);
904 if (*endc || tmp_port == 0)
905 {
906 DEBUG(D_receive)
907 debug_printf("Proxied src port '%s' not an integer\n", p);
908 goto proxyfail;
909 }
910 proxy_host_port = sender_host_port;
911 sender_host_port = tmp_port;
912 p = sp + 1;
913 if ((sp = Ustrchr(p, '\0')) == NULL)
914 {
915 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
916 goto proxyfail;
917 }
918 tmp_port = strtol(CCS p,&endc,10);
919 if (*endc || tmp_port == 0)
920 {
921 DEBUG(D_receive)
922 debug_printf("Proxy dest port '%s' not an integer\n", p);
923 goto proxyfail;
924 }
925 proxy_target_port = tmp_port;
926 /* Already checked for /r /n above. Good V1 header received. */
927 goto done;
928 }
929 else
930 {
931 /* Wrong protocol */
932 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
933 goto proxyfail;
934 }
935
936 proxyfail:
937 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
938 /* Don't flush any potential buffer contents. Any input should cause a
939 synchronization failure */
940 return FALSE;
941
942 done:
943 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
944 DEBUG(D_receive)
945 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
946 return proxy_session;
947 }
948 #endif
949
950 /*************************************************
951 * Read one command line *
952 *************************************************/
953
954 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
955 There are sites that don't do this, and in any case internal SMTP probably
956 should check only for LF. Consequently, we check here for LF only. The line
957 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
958 an unknown command. The command is read into the global smtp_cmd_buffer so that
959 it is available via $smtp_command.
960
961 The character reading routine sets up a timeout for each block actually read
962 from the input (which may contain more than one command). We set up a special
963 signal handler that closes down the session on a timeout. Control does not
964 return when it runs.
965
966 Arguments:
967 check_sync if TRUE, check synchronization rules if global option is TRUE
968
969 Returns: a code identifying the command (enumerated above)
970 */
971
972 static int
973 smtp_read_command(BOOL check_sync)
974 {
975 int c;
976 int ptr = 0;
977 smtp_cmd_list *p;
978 BOOL hadnull = FALSE;
979
980 os_non_restarting_signal(SIGALRM, command_timeout_handler);
981
982 while ((c = (receive_getc)()) != '\n' && c != EOF)
983 {
984 if (ptr >= smtp_cmd_buffer_size)
985 {
986 os_non_restarting_signal(SIGALRM, sigalrm_handler);
987 return OTHER_CMD;
988 }
989 if (c == 0)
990 {
991 hadnull = TRUE;
992 c = '?';
993 }
994 smtp_cmd_buffer[ptr++] = c;
995 }
996
997 receive_linecount++; /* For BSMTP errors */
998 os_non_restarting_signal(SIGALRM, sigalrm_handler);
999
1000 /* If hit end of file, return pseudo EOF command. Whether we have a
1001 part-line already read doesn't matter, since this is an error state. */
1002
1003 if (c == EOF) return EOF_CMD;
1004
1005 /* Remove any CR and white space at the end of the line, and terminate the
1006 string. */
1007
1008 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1009 smtp_cmd_buffer[ptr] = 0;
1010
1011 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1012
1013 /* NULLs are not allowed in SMTP commands */
1014
1015 if (hadnull) return BADCHAR_CMD;
1016
1017 /* Scan command list and return identity, having set the data pointer
1018 to the start of the actual data characters. Check for SMTP synchronization
1019 if required. */
1020
1021 for (p = cmd_list; p < cmd_list_end; p++)
1022 {
1023 #ifdef EXPERIMENTAL_PROXY
1024 /* Only allow QUIT command if Proxy Protocol parsing failed */
1025 if (proxy_session && proxy_session_failed)
1026 {
1027 if (p->cmd != QUIT_CMD)
1028 continue;
1029 }
1030 #endif
1031 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
1032 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
1033 smtp_cmd_buffer[p->len] == 0 ||
1034 smtp_cmd_buffer[p->len] == ' '))
1035 {
1036 if (smtp_inptr < smtp_inend && /* Outstanding input */
1037 p->cmd < sync_cmd_limit && /* Command should sync */
1038 check_sync && /* Local flag set */
1039 smtp_enforce_sync && /* Global flag set */
1040 sender_host_address != NULL && /* Not local input */
1041 !sender_host_notsocket) /* Really is a socket */
1042 return BADSYN_CMD;
1043
1044 /* The variables $smtp_command and $smtp_command_argument point into the
1045 unmodified input buffer. A copy of the latter is taken for actual
1046 processing, so that it can be chopped up into separate parts if necessary,
1047 for example, when processing a MAIL command options such as SIZE that can
1048 follow the sender address. */
1049
1050 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1051 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1052 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1053 smtp_cmd_data = smtp_data_buffer;
1054
1055 /* Count non-mail commands from those hosts that are controlled in this
1056 way. The default is all hosts. We don't waste effort checking the list
1057 until we get a non-mail command, but then cache the result to save checking
1058 again. If there's a DEFER while checking the host, assume it's in the list.
1059
1060 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1061 start of each incoming message by fiddling with the value in the table. */
1062
1063 if (!p->is_mail_cmd)
1064 {
1065 if (count_nonmail == TRUE_UNSET) count_nonmail =
1066 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1067 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1068 return TOO_MANY_NONMAIL_CMD;
1069 }
1070
1071 /* If there is data for a command that does not expect it, generate the
1072 error here. */
1073
1074 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1075 }
1076 }
1077
1078 #ifdef EXPERIMENTAL_PROXY
1079 /* Only allow QUIT command if Proxy Protocol parsing failed */
1080 if (proxy_session && proxy_session_failed)
1081 return PROXY_FAIL_IGNORE_CMD;
1082 #endif
1083
1084 /* Enforce synchronization for unknown commands */
1085
1086 if (smtp_inptr < smtp_inend && /* Outstanding input */
1087 check_sync && /* Local flag set */
1088 smtp_enforce_sync && /* Global flag set */
1089 sender_host_address != NULL && /* Not local input */
1090 !sender_host_notsocket) /* Really is a socket */
1091 return BADSYN_CMD;
1092
1093 return OTHER_CMD;
1094 }
1095
1096
1097
1098 /*************************************************
1099 * Recheck synchronization *
1100 *************************************************/
1101
1102 /* Synchronization checks can never be perfect because a packet may be on its
1103 way but not arrived when the check is done. Such checks can in any case only be
1104 done when TLS is not in use. Normally, the checks happen when commands are
1105 read: Exim ensures that there is no more input in the input buffer. In normal
1106 cases, the response to the command will be fast, and there is no further check.
1107
1108 However, for some commands an ACL is run, and that can include delays. In those
1109 cases, it is useful to do another check on the input just before sending the
1110 response. This also applies at the start of a connection. This function does
1111 that check by means of the select() function, as long as the facility is not
1112 disabled or inappropriate. A failure of select() is ignored.
1113
1114 When there is unwanted input, we read it so that it appears in the log of the
1115 error.
1116
1117 Arguments: none
1118 Returns: TRUE if all is well; FALSE if there is input pending
1119 */
1120
1121 static BOOL
1122 check_sync(void)
1123 {
1124 int fd, rc;
1125 fd_set fds;
1126 struct timeval tzero;
1127
1128 if (!smtp_enforce_sync || sender_host_address == NULL ||
1129 sender_host_notsocket || tls_in.active >= 0)
1130 return TRUE;
1131
1132 fd = fileno(smtp_in);
1133 FD_ZERO(&fds);
1134 FD_SET(fd, &fds);
1135 tzero.tv_sec = 0;
1136 tzero.tv_usec = 0;
1137 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1138
1139 if (rc <= 0) return TRUE; /* Not ready to read */
1140 rc = smtp_getc();
1141 if (rc < 0) return TRUE; /* End of file or error */
1142
1143 smtp_ungetc(rc);
1144 rc = smtp_inend - smtp_inptr;
1145 if (rc > 150) rc = 150;
1146 smtp_inptr[rc] = 0;
1147 return FALSE;
1148 }
1149
1150
1151
1152 /*************************************************
1153 * Forced closedown of call *
1154 *************************************************/
1155
1156 /* This function is called from log.c when Exim is dying because of a serious
1157 disaster, and also from some other places. If an incoming non-batched SMTP
1158 channel is open, it swallows the rest of the incoming message if in the DATA
1159 phase, sends the reply string, and gives an error to all subsequent commands
1160 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1161 smtp_in.
1162
1163 Arguments:
1164 message SMTP reply string to send, excluding the code
1165
1166 Returns: nothing
1167 */
1168
1169 void
1170 smtp_closedown(uschar *message)
1171 {
1172 if (smtp_in == NULL || smtp_batched_input) return;
1173 receive_swallow_smtp();
1174 smtp_printf("421 %s\r\n", message);
1175
1176 for (;;)
1177 {
1178 switch(smtp_read_command(FALSE))
1179 {
1180 case EOF_CMD:
1181 return;
1182
1183 case QUIT_CMD:
1184 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1185 mac_smtp_fflush();
1186 return;
1187
1188 case RSET_CMD:
1189 smtp_printf("250 Reset OK\r\n");
1190 break;
1191
1192 default:
1193 smtp_printf("421 %s\r\n", message);
1194 break;
1195 }
1196 }
1197 }
1198
1199
1200
1201
1202 /*************************************************
1203 * Set up connection info for logging *
1204 *************************************************/
1205
1206 /* This function is called when logging information about an SMTP connection.
1207 It sets up appropriate source information, depending on the type of connection.
1208 If sender_fullhost is NULL, we are at a very early stage of the connection;
1209 just use the IP address.
1210
1211 Argument: none
1212 Returns: a string describing the connection
1213 */
1214
1215 uschar *
1216 smtp_get_connection_info(void)
1217 {
1218 uschar *hostname = (sender_fullhost == NULL)?
1219 sender_host_address : sender_fullhost;
1220
1221 if (host_checking)
1222 return string_sprintf("SMTP connection from %s", hostname);
1223
1224 if (sender_host_unknown || sender_host_notsocket)
1225 return string_sprintf("SMTP connection from %s", sender_ident);
1226
1227 if (is_inetd)
1228 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1229
1230 if ((log_extra_selector & LX_incoming_interface) != 0 &&
1231 interface_address != NULL)
1232 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1233 interface_address, interface_port);
1234
1235 return string_sprintf("SMTP connection from %s", hostname);
1236 }
1237
1238
1239
1240 #ifdef SUPPORT_TLS
1241 /* Append TLS-related information to a log line
1242
1243 Arguments:
1244 s String under construction: allocated string to extend, or NULL
1245 sizep Pointer to current allocation size (update on return), or NULL
1246 ptrp Pointer to index for new entries in string (update on return), or NULL
1247
1248 Returns: Allocated string or NULL
1249 */
1250 static uschar *
1251 s_tlslog(uschar * s, int * sizep, int * ptrp)
1252 {
1253 int size = sizep ? *sizep : 0;
1254 int ptr = ptrp ? *ptrp : 0;
1255
1256 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_in.cipher != NULL)
1257 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1258 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
1259 tls_in.cipher != NULL)
1260 s = string_append(s, &size, &ptr, 2, US" CV=",
1261 tls_in.certificate_verified? "yes":"no");
1262 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_in.peerdn != NULL)
1263 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1264 string_printing(tls_in.peerdn), US"\"");
1265 if ((log_extra_selector & LX_tls_sni) != 0 && tls_in.sni != NULL)
1266 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1267 string_printing(tls_in.sni), US"\"");
1268
1269 if (s)
1270 {
1271 s[ptr] = '\0';
1272 if (sizep) *sizep = size;
1273 if (ptrp) *ptrp = ptr;
1274 }
1275 return s;
1276 }
1277 #endif
1278
1279 /*************************************************
1280 * Log lack of MAIL if so configured *
1281 *************************************************/
1282
1283 /* This function is called when an SMTP session ends. If the log selector
1284 smtp_no_mail is set, write a log line giving some details of what has happened
1285 in the SMTP session.
1286
1287 Arguments: none
1288 Returns: nothing
1289 */
1290
1291 void
1292 smtp_log_no_mail(void)
1293 {
1294 int size, ptr, i;
1295 uschar *s, *sep;
1296
1297 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
1298 return;
1299
1300 s = NULL;
1301 size = ptr = 0;
1302
1303 if (sender_host_authenticated != NULL)
1304 {
1305 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1306 if (authenticated_id != NULL)
1307 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1308 }
1309
1310 #ifdef SUPPORT_TLS
1311 s = s_tlslog(s, &size, &ptr);
1312 #endif
1313
1314 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1315 US" C=..." : US" C=";
1316 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1317 {
1318 if (smtp_connection_had[i] != SCH_NONE)
1319 {
1320 s = string_append(s, &size, &ptr, 2, sep,
1321 smtp_names[smtp_connection_had[i]]);
1322 sep = US",";
1323 }
1324 }
1325
1326 for (i = 0; i < smtp_ch_index; i++)
1327 {
1328 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1329 sep = US",";
1330 }
1331
1332 if (s != NULL) s[ptr] = 0; else s = US"";
1333 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1334 host_and_ident(FALSE),
1335 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1336 s);
1337 }
1338
1339
1340
1341 /*************************************************
1342 * Check HELO line and set sender_helo_name *
1343 *************************************************/
1344
1345 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1346 the domain name of the sending host, or an ip literal in square brackets. The
1347 arrgument is placed in sender_helo_name, which is in malloc store, because it
1348 must persist over multiple incoming messages. If helo_accept_junk is set, this
1349 host is permitted to send any old junk (needed for some broken hosts).
1350 Otherwise, helo_allow_chars can be used for rogue characters in general
1351 (typically people want to let in underscores).
1352
1353 Argument:
1354 s the data portion of the line (already past any white space)
1355
1356 Returns: TRUE or FALSE
1357 */
1358
1359 static BOOL
1360 check_helo(uschar *s)
1361 {
1362 uschar *start = s;
1363 uschar *end = s + Ustrlen(s);
1364 BOOL yield = helo_accept_junk;
1365
1366 /* Discard any previous helo name */
1367
1368 if (sender_helo_name != NULL)
1369 {
1370 store_free(sender_helo_name);
1371 sender_helo_name = NULL;
1372 }
1373
1374 /* Skip tests if junk is permitted. */
1375
1376 if (!yield)
1377 {
1378 /* Allow the new standard form for IPv6 address literals, namely,
1379 [IPv6:....], and because someone is bound to use it, allow an equivalent
1380 IPv4 form. Allow plain addresses as well. */
1381
1382 if (*s == '[')
1383 {
1384 if (end[-1] == ']')
1385 {
1386 end[-1] = 0;
1387 if (strncmpic(s, US"[IPv6:", 6) == 0)
1388 yield = (string_is_ip_address(s+6, NULL) == 6);
1389 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1390 yield = (string_is_ip_address(s+6, NULL) == 4);
1391 else
1392 yield = (string_is_ip_address(s+1, NULL) != 0);
1393 end[-1] = ']';
1394 }
1395 }
1396
1397 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1398 that have been configured (usually underscore - sigh). */
1399
1400 else if (*s != 0)
1401 {
1402 yield = TRUE;
1403 while (*s != 0)
1404 {
1405 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1406 Ustrchr(helo_allow_chars, *s) == NULL)
1407 {
1408 yield = FALSE;
1409 break;
1410 }
1411 s++;
1412 }
1413 }
1414 }
1415
1416 /* Save argument if OK */
1417
1418 if (yield) sender_helo_name = string_copy_malloc(start);
1419 return yield;
1420 }
1421
1422
1423
1424
1425
1426 /*************************************************
1427 * Extract SMTP command option *
1428 *************************************************/
1429
1430 /* This function picks the next option setting off the end of smtp_cmd_data. It
1431 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1432 things that can appear there.
1433
1434 Arguments:
1435 name point this at the name
1436 value point this at the data string
1437
1438 Returns: TRUE if found an option
1439 */
1440
1441 static BOOL
1442 extract_option(uschar **name, uschar **value)
1443 {
1444 uschar *n;
1445 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1446 while (isspace(*v)) v--;
1447 v[1] = 0;
1448 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1449
1450 n = v;
1451 if (*v == '=')
1452 {
1453 while(isalpha(n[-1])) n--;
1454 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1455 if (!isspace(n[-1])) return FALSE;
1456 n[-1] = 0;
1457 }
1458 else
1459 {
1460 n++;
1461 if (v == smtp_cmd_data) return FALSE;
1462 }
1463 *v++ = 0;
1464 *name = n;
1465 *value = v;
1466 return TRUE;
1467 }
1468
1469
1470
1471
1472
1473 /*************************************************
1474 * Reset for new message *
1475 *************************************************/
1476
1477 /* This function is called whenever the SMTP session is reset from
1478 within either of the setup functions.
1479
1480 Argument: the stacking pool storage reset point
1481 Returns: nothing
1482 */
1483
1484 static void
1485 smtp_reset(void *reset_point)
1486 {
1487 store_reset(reset_point);
1488 recipients_list = NULL;
1489 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1490 raw_recipients_count = recipients_count = recipients_list_max = 0;
1491 cancel_cutthrough_connection("smtp reset");
1492 message_linecount = 0;
1493 message_size = -1;
1494 acl_added_headers = NULL;
1495 acl_removed_headers = NULL;
1496 queue_only_policy = FALSE;
1497 rcpt_smtp_response = NULL;
1498 rcpt_smtp_response_same = TRUE;
1499 rcpt_in_progress = FALSE;
1500 deliver_freeze = FALSE; /* Can be set by ACL */
1501 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1502 fake_response = OK; /* Can be set by ACL */
1503 #ifdef WITH_CONTENT_SCAN
1504 no_mbox_unspool = FALSE; /* Can be set by ACL */
1505 #endif
1506 submission_mode = FALSE; /* Can be set by ACL */
1507 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1508 active_local_from_check = local_from_check; /* Can be set by ACL */
1509 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1510 sender_address = NULL;
1511 submission_name = NULL; /* Can be set by ACL */
1512 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1513 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1514 sender_verified_list = NULL; /* No senders verified */
1515 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1516 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1517
1518 #ifndef DISABLE_PRDR
1519 prdr_requested = FALSE;
1520 #endif
1521
1522 /* Reset the DSN flags */
1523 dsn_ret = 0;
1524 dsn_envid = NULL;
1525
1526 authenticated_sender = NULL;
1527 #ifdef EXPERIMENTAL_BRIGHTMAIL
1528 bmi_run = 0;
1529 bmi_verdicts = NULL;
1530 #endif
1531 #ifndef DISABLE_DKIM
1532 dkim_signers = NULL;
1533 dkim_disable_verify = FALSE;
1534 dkim_collect_input = FALSE;
1535 #endif
1536 #ifdef EXPERIMENTAL_SPF
1537 spf_header_comment = NULL;
1538 spf_received = NULL;
1539 spf_result = NULL;
1540 spf_smtp_comment = NULL;
1541 #endif
1542 #ifdef EXPERIMENTAL_INTERNATIONAL
1543 message_smtputf8 = FALSE;
1544 #endif
1545 body_linecount = body_zerocount = 0;
1546
1547 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1548 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1549 /* Note that ratelimiters_conn persists across resets. */
1550
1551 /* Reset message ACL variables */
1552
1553 acl_var_m = NULL;
1554
1555 /* The message body variables use malloc store. They may be set if this is
1556 not the first message in an SMTP session and the previous message caused them
1557 to be referenced in an ACL. */
1558
1559 if (message_body != NULL)
1560 {
1561 store_free(message_body);
1562 message_body = NULL;
1563 }
1564
1565 if (message_body_end != NULL)
1566 {
1567 store_free(message_body_end);
1568 message_body_end = NULL;
1569 }
1570
1571 /* Warning log messages are also saved in malloc store. They are saved to avoid
1572 repetition in the same message, but it seems right to repeat them for different
1573 messages. */
1574
1575 while (acl_warn_logged != NULL)
1576 {
1577 string_item *this = acl_warn_logged;
1578 acl_warn_logged = acl_warn_logged->next;
1579 store_free(this);
1580 }
1581 }
1582
1583
1584
1585
1586
1587 /*************************************************
1588 * Initialize for incoming batched SMTP message *
1589 *************************************************/
1590
1591 /* This function is called from smtp_setup_msg() in the case when
1592 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1593 of messages in one file with SMTP commands between them. All errors must be
1594 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1595 relevant. After an error on a sender, or an invalid recipient, the remainder
1596 of the message is skipped. The value of received_protocol is already set.
1597
1598 Argument: none
1599 Returns: > 0 message successfully started (reached DATA)
1600 = 0 QUIT read or end of file reached
1601 < 0 should not occur
1602 */
1603
1604 static int
1605 smtp_setup_batch_msg(void)
1606 {
1607 int done = 0;
1608 void *reset_point = store_get(0);
1609
1610 /* Save the line count at the start of each transaction - single commands
1611 like HELO and RSET count as whole transactions. */
1612
1613 bsmtp_transaction_linecount = receive_linecount;
1614
1615 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1616
1617 smtp_reset(reset_point); /* Reset for start of message */
1618
1619 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1620 value. The values are 2 larger than the required yield of the function. */
1621
1622 while (done <= 0)
1623 {
1624 uschar *errmess;
1625 uschar *recipient = NULL;
1626 int start, end, sender_domain, recipient_domain;
1627
1628 switch(smtp_read_command(FALSE))
1629 {
1630 /* The HELO/EHLO commands set sender_address_helo if they have
1631 valid data; otherwise they are ignored, except that they do
1632 a reset of the state. */
1633
1634 case HELO_CMD:
1635 case EHLO_CMD:
1636
1637 check_helo(smtp_cmd_data);
1638 /* Fall through */
1639
1640 case RSET_CMD:
1641 smtp_reset(reset_point);
1642 bsmtp_transaction_linecount = receive_linecount;
1643 break;
1644
1645
1646 /* The MAIL FROM command requires an address as an operand. All we
1647 do here is to parse it for syntactic correctness. The form "<>" is
1648 a special case which converts into an empty string. The start/end
1649 pointers in the original are not used further for this address, as
1650 it is the canonical extracted address which is all that is kept. */
1651
1652 case MAIL_CMD:
1653 smtp_mailcmd_count++; /* Count for no-mail log */
1654 if (sender_address != NULL)
1655 /* The function moan_smtp_batch() does not return. */
1656 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1657
1658 if (smtp_cmd_data[0] == 0)
1659 /* The function moan_smtp_batch() does not return. */
1660 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1661
1662 /* Reset to start of message */
1663
1664 smtp_reset(reset_point);
1665
1666 /* Apply SMTP rewrite */
1667
1668 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1669 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1670 US"", global_rewrite_rules) : smtp_cmd_data;
1671
1672 /* Extract the address; the TRUE flag allows <> as valid */
1673
1674 raw_sender =
1675 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1676 TRUE);
1677
1678 if (raw_sender == NULL)
1679 /* The function moan_smtp_batch() does not return. */
1680 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1681
1682 sender_address = string_copy(raw_sender);
1683
1684 /* Qualify unqualified sender addresses if permitted to do so. */
1685
1686 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1687 {
1688 if (allow_unqualified_sender)
1689 {
1690 sender_address = rewrite_address_qualify(sender_address, FALSE);
1691 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1692 "and rewritten\n", raw_sender);
1693 }
1694 /* The function moan_smtp_batch() does not return. */
1695 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1696 "a domain");
1697 }
1698 break;
1699
1700
1701 /* The RCPT TO command requires an address as an operand. All we do
1702 here is to parse it for syntactic correctness. There may be any number
1703 of RCPT TO commands, specifying multiple senders. We build them all into
1704 a data structure that is in argc/argv format. The start/end values
1705 given by parse_extract_address are not used, as we keep only the
1706 extracted address. */
1707
1708 case RCPT_CMD:
1709 if (sender_address == NULL)
1710 /* The function moan_smtp_batch() does not return. */
1711 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1712
1713 if (smtp_cmd_data[0] == 0)
1714 /* The function moan_smtp_batch() does not return. */
1715 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1716
1717 /* Check maximum number allowed */
1718
1719 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1720 /* The function moan_smtp_batch() does not return. */
1721 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1722 recipients_max_reject? "552": "452");
1723
1724 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1725 recipient address */
1726
1727 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1728 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1729 global_rewrite_rules) : smtp_cmd_data;
1730
1731 /* rfc821_domains = TRUE; << no longer needed */
1732 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1733 &recipient_domain, FALSE);
1734 /* rfc821_domains = FALSE; << no longer needed */
1735
1736 if (recipient == NULL)
1737 /* The function moan_smtp_batch() does not return. */
1738 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1739
1740 /* If the recipient address is unqualified, qualify it if permitted. Then
1741 add it to the list of recipients. */
1742
1743 if (recipient_domain == 0)
1744 {
1745 if (allow_unqualified_recipient)
1746 {
1747 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1748 recipient);
1749 recipient = rewrite_address_qualify(recipient, TRUE);
1750 }
1751 /* The function moan_smtp_batch() does not return. */
1752 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1753 "a domain");
1754 }
1755 receive_add_recipient(recipient, -1);
1756 break;
1757
1758
1759 /* The DATA command is legal only if it follows successful MAIL FROM
1760 and RCPT TO commands. This function is complete when a valid DATA
1761 command is encountered. */
1762
1763 case DATA_CMD:
1764 if (sender_address == NULL || recipients_count <= 0)
1765 {
1766 /* The function moan_smtp_batch() does not return. */
1767 if (sender_address == NULL)
1768 moan_smtp_batch(smtp_cmd_buffer,
1769 "503 MAIL FROM:<sender> command must precede DATA");
1770 else
1771 moan_smtp_batch(smtp_cmd_buffer,
1772 "503 RCPT TO:<recipient> must precede DATA");
1773 }
1774 else
1775 {
1776 done = 3; /* DATA successfully achieved */
1777 message_ended = END_NOTENDED; /* Indicate in middle of message */
1778 }
1779 break;
1780
1781
1782 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1783
1784 case VRFY_CMD:
1785 case EXPN_CMD:
1786 case HELP_CMD:
1787 case NOOP_CMD:
1788 case ETRN_CMD:
1789 bsmtp_transaction_linecount = receive_linecount;
1790 break;
1791
1792
1793 case EOF_CMD:
1794 case QUIT_CMD:
1795 done = 2;
1796 break;
1797
1798
1799 case BADARG_CMD:
1800 /* The function moan_smtp_batch() does not return. */
1801 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1802 break;
1803
1804
1805 case BADCHAR_CMD:
1806 /* The function moan_smtp_batch() does not return. */
1807 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1808 break;
1809
1810
1811 default:
1812 /* The function moan_smtp_batch() does not return. */
1813 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1814 break;
1815 }
1816 }
1817
1818 return done - 2; /* Convert yield values */
1819 }
1820
1821
1822
1823
1824 /*************************************************
1825 * Start an SMTP session *
1826 *************************************************/
1827
1828 /* This function is called at the start of an SMTP session. Thereafter,
1829 smtp_setup_msg() is called to initiate each separate message. This
1830 function does host-specific testing, and outputs the banner line.
1831
1832 Arguments: none
1833 Returns: FALSE if the session can not continue; something has
1834 gone wrong, or the connection to the host is blocked
1835 */
1836
1837 BOOL
1838 smtp_start_session(void)
1839 {
1840 int size = 256;
1841 int ptr, esclen;
1842 uschar *user_msg, *log_msg;
1843 uschar *code, *esc;
1844 uschar *p, *s, *ss;
1845
1846 smtp_connection_start = time(NULL);
1847 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1848 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1849 smtp_ch_index = 0;
1850
1851 /* Default values for certain variables */
1852
1853 helo_seen = esmtp = helo_accept_junk = FALSE;
1854 smtp_mailcmd_count = 0;
1855 count_nonmail = TRUE_UNSET;
1856 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1857 smtp_delay_mail = smtp_rlm_base;
1858 auth_advertised = FALSE;
1859 pipelining_advertised = FALSE;
1860 pipelining_enable = TRUE;
1861 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1862 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1863
1864 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1865
1866 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1867 authentication settings from -oMaa to remain in force. */
1868
1869 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1870 authenticated_by = NULL;
1871
1872 #ifdef SUPPORT_TLS
1873 tls_in.cipher = tls_in.peerdn = NULL;
1874 tls_in.ourcert = tls_in.peercert = NULL;
1875 tls_in.sni = NULL;
1876 tls_in.ocsp = OCSP_NOT_REQ;
1877 tls_advertised = FALSE;
1878 #endif
1879 dsn_advertised = FALSE;
1880 #ifdef EXPERIMENTAL_INTERNATIONAL
1881 smtputf8_advertised = FALSE;
1882 #endif
1883
1884 /* Reset ACL connection variables */
1885
1886 acl_var_c = NULL;
1887
1888 /* Allow for trailing 0 in the command and data buffers. */
1889
1890 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1891 if (smtp_cmd_buffer == NULL)
1892 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1893 "malloc() failed for SMTP command buffer");
1894 smtp_cmd_buffer[0] = 0;
1895 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1896
1897 /* For batched input, the protocol setting can be overridden from the
1898 command line by a trusted caller. */
1899
1900 if (smtp_batched_input)
1901 {
1902 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1903 }
1904
1905 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1906 reset later if any of EHLO/AUTH/STARTTLS are received. */
1907
1908 else
1909 received_protocol =
1910 (sender_host_address ? protocols : protocols_local) [pnormal];
1911
1912 /* Set up the buffer for inputting using direct read() calls, and arrange to
1913 call the local functions instead of the standard C ones. */
1914
1915 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1916 if (smtp_inbuffer == NULL)
1917 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1918 receive_getc = smtp_getc;
1919 receive_ungetc = smtp_ungetc;
1920 receive_feof = smtp_feof;
1921 receive_ferror = smtp_ferror;
1922 receive_smtp_buffered = smtp_buffered;
1923 smtp_inptr = smtp_inend = smtp_inbuffer;
1924 smtp_had_eof = smtp_had_error = 0;
1925
1926 /* Set up the message size limit; this may be host-specific */
1927
1928 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1929 if (expand_string_message != NULL)
1930 {
1931 if (thismessage_size_limit == -1)
1932 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1933 "%s", expand_string_message);
1934 else
1935 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1936 "%s", expand_string_message);
1937 smtp_closedown(US"Temporary local problem - please try later");
1938 return FALSE;
1939 }
1940
1941 /* When a message is input locally via the -bs or -bS options, sender_host_
1942 unknown is set unless -oMa was used to force an IP address, in which case it
1943 is checked like a real remote connection. When -bs is used from inetd, this
1944 flag is not set, causing the sending host to be checked. The code that deals
1945 with IP source routing (if configured) is never required for -bs or -bS and
1946 the flag sender_host_notsocket is used to suppress it.
1947
1948 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1949 reserve for certain hosts and/or networks. */
1950
1951 if (!sender_host_unknown)
1952 {
1953 int rc;
1954 BOOL reserved_host = FALSE;
1955
1956 /* Look up IP options (source routing info) on the socket if this is not an
1957 -oMa "host", and if any are found, log them and drop the connection.
1958
1959 Linux (and others now, see below) is different to everyone else, so there
1960 has to be some conditional compilation here. Versions of Linux before 2.1.15
1961 used a structure whose name was "options". Somebody finally realized that
1962 this name was silly, and it got changed to "ip_options". I use the
1963 newer name here, but there is a fudge in the script that sets up os.h
1964 to define a macro in older Linux systems.
1965
1966 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1967 glibc 2, which has chosen ip_opts for the structure name. This is now
1968 really a glibc thing rather than a Linux thing, so the condition name
1969 has been changed to reflect this. It is relevant also to GNU/Hurd.
1970
1971 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1972 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1973 a special macro defined in the os.h file.
1974
1975 Some DGUX versions on older hardware appear not to support IP options at
1976 all, so there is now a general macro which can be set to cut out this
1977 support altogether.
1978
1979 How to do this properly in IPv6 is not yet known. */
1980
1981 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1982
1983 #ifdef GLIBC_IP_OPTIONS
1984 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1985 #define OPTSTYLE 1
1986 #else
1987 #define OPTSTYLE 2
1988 #endif
1989 #elif defined DARWIN_IP_OPTIONS
1990 #define OPTSTYLE 2
1991 #else
1992 #define OPTSTYLE 3
1993 #endif
1994
1995 if (!host_checking && !sender_host_notsocket)
1996 {
1997 #if OPTSTYLE == 1
1998 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1999 struct ip_options *ipopt = store_get(optlen);
2000 #elif OPTSTYLE == 2
2001 struct ip_opts ipoptblock;
2002 struct ip_opts *ipopt = &ipoptblock;
2003 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2004 #else
2005 struct ipoption ipoptblock;
2006 struct ipoption *ipopt = &ipoptblock;
2007 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2008 #endif
2009
2010 /* Occasional genuine failures of getsockopt() have been seen - for
2011 example, "reset by peer". Therefore, just log and give up on this
2012 call, unless the error is ENOPROTOOPT. This error is given by systems
2013 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2014 of writing. So for that error, carry on - we just can't do an IP options
2015 check. */
2016
2017 DEBUG(D_receive) debug_printf("checking for IP options\n");
2018
2019 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2020 &optlen) < 0)
2021 {
2022 if (errno != ENOPROTOOPT)
2023 {
2024 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2025 host_and_ident(FALSE), strerror(errno));
2026 smtp_printf("451 SMTP service not available\r\n");
2027 return FALSE;
2028 }
2029 }
2030
2031 /* Deal with any IP options that are set. On the systems I have looked at,
2032 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2033 more logging data than will fit in big_buffer. Nevertheless, after somebody
2034 questioned this code, I've added in some paranoid checking. */
2035
2036 else if (optlen > 0)
2037 {
2038 uschar *p = big_buffer;
2039 uschar *pend = big_buffer + big_buffer_size;
2040 uschar *opt, *adptr;
2041 int optcount;
2042 struct in_addr addr;
2043
2044 #if OPTSTYLE == 1
2045 uschar *optstart = (uschar *)(ipopt->__data);
2046 #elif OPTSTYLE == 2
2047 uschar *optstart = (uschar *)(ipopt->ip_opts);
2048 #else
2049 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2050 #endif
2051
2052 DEBUG(D_receive) debug_printf("IP options exist\n");
2053
2054 Ustrcpy(p, "IP options on incoming call:");
2055 p += Ustrlen(p);
2056
2057 for (opt = optstart; opt != NULL &&
2058 opt < (uschar *)(ipopt) + optlen;)
2059 {
2060 switch (*opt)
2061 {
2062 case IPOPT_EOL:
2063 opt = NULL;
2064 break;
2065
2066 case IPOPT_NOP:
2067 opt++;
2068 break;
2069
2070 case IPOPT_SSRR:
2071 case IPOPT_LSRR:
2072 if (!string_format(p, pend-p, " %s [@%s",
2073 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2074 #if OPTSTYLE == 1
2075 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2076 #elif OPTSTYLE == 2
2077 inet_ntoa(ipopt->ip_dst)))
2078 #else
2079 inet_ntoa(ipopt->ipopt_dst)))
2080 #endif
2081 {
2082 opt = NULL;
2083 break;
2084 }
2085
2086 p += Ustrlen(p);
2087 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2088 adptr = opt + 3;
2089 while (optcount-- > 0)
2090 {
2091 memcpy(&addr, adptr, sizeof(addr));
2092 if (!string_format(p, pend - p - 1, "%s%s",
2093 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2094 {
2095 opt = NULL;
2096 break;
2097 }
2098 p += Ustrlen(p);
2099 adptr += sizeof(struct in_addr);
2100 }
2101 *p++ = ']';
2102 opt += opt[1];
2103 break;
2104
2105 default:
2106 {
2107 int i;
2108 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2109 Ustrcat(p, "[ ");
2110 p += 2;
2111 for (i = 0; i < opt[1]; i++)
2112 {
2113 sprintf(CS p, "%2.2x ", opt[i]);
2114 p += 3;
2115 }
2116 *p++ = ']';
2117 }
2118 opt += opt[1];
2119 break;
2120 }
2121 }
2122
2123 *p = 0;
2124 log_write(0, LOG_MAIN, "%s", big_buffer);
2125
2126 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2127
2128 log_write(0, LOG_MAIN|LOG_REJECT,
2129 "connection from %s refused (IP options)", host_and_ident(FALSE));
2130
2131 smtp_printf("554 SMTP service not available\r\n");
2132 return FALSE;
2133 }
2134
2135 /* Length of options = 0 => there are no options */
2136
2137 else DEBUG(D_receive) debug_printf("no IP options found\n");
2138 }
2139 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2140
2141 /* Set keep-alive in socket options. The option is on by default. This
2142 setting is an attempt to get rid of some hanging connections that stick in
2143 read() when the remote end (usually a dialup) goes away. */
2144
2145 if (smtp_accept_keepalive && !sender_host_notsocket)
2146 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2147
2148 /* If the current host matches host_lookup, set the name by doing a
2149 reverse lookup. On failure, sender_host_name will be NULL and
2150 host_lookup_failed will be TRUE. This may or may not be serious - optional
2151 checks later. */
2152
2153 if (verify_check_host(&host_lookup) == OK)
2154 {
2155 (void)host_name_lookup();
2156 host_build_sender_fullhost();
2157 }
2158
2159 /* Delay this until we have the full name, if it is looked up. */
2160
2161 set_process_info("handling incoming connection from %s",
2162 host_and_ident(FALSE));
2163
2164 /* Expand smtp_receive_timeout, if needed */
2165
2166 if (smtp_receive_timeout_s)
2167 {
2168 uschar * exp;
2169 if ( !(exp = expand_string(smtp_receive_timeout_s))
2170 || !(*exp)
2171 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2172 )
2173 log_write(0, LOG_MAIN|LOG_PANIC,
2174 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2175 }
2176
2177 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2178 smtps port for use with older style SSL MTAs. */
2179
2180 #ifdef SUPPORT_TLS
2181 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2182 return FALSE;
2183 #endif
2184
2185 /* Test for explicit connection rejection */
2186
2187 if (verify_check_host(&host_reject_connection) == OK)
2188 {
2189 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2190 "from %s (host_reject_connection)", host_and_ident(FALSE));
2191 smtp_printf("554 SMTP service not available\r\n");
2192 return FALSE;
2193 }
2194
2195 /* Test with TCP Wrappers if so configured. There is a problem in that
2196 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2197 such as disks dying. In these cases, it is desirable to reject with a 4xx
2198 error instead of a 5xx error. There isn't a "right" way to detect such
2199 problems. The following kludge is used: errno is zeroed before calling
2200 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2201 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2202 not exist). */
2203
2204 #ifdef USE_TCP_WRAPPERS
2205 errno = 0;
2206 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2207 if (tcp_wrappers_name == NULL)
2208 {
2209 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2210 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2211 expand_string_message);
2212 }
2213 if (!hosts_ctl(tcp_wrappers_name,
2214 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2215 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2216 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2217 {
2218 if (errno == 0 || errno == ENOENT)
2219 {
2220 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2221 log_write(L_connection_reject,
2222 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2223 "(tcp wrappers)", host_and_ident(FALSE));
2224 smtp_printf("554 SMTP service not available\r\n");
2225 }
2226 else
2227 {
2228 int save_errno = errno;
2229 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2230 "errno value %d\n", save_errno);
2231 log_write(L_connection_reject,
2232 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2233 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2234 smtp_printf("451 Temporary local problem - please try later\r\n");
2235 }
2236 return FALSE;
2237 }
2238 #endif
2239
2240 /* Check for reserved slots. The value of smtp_accept_count has already been
2241 incremented to include this process. */
2242
2243 if (smtp_accept_max > 0 &&
2244 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2245 {
2246 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2247 {
2248 log_write(L_connection_reject,
2249 LOG_MAIN, "temporarily refused connection from %s: not in "
2250 "reserve list: connected=%d max=%d reserve=%d%s",
2251 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2252 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2253 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2254 "please try again later\r\n", smtp_active_hostname);
2255 return FALSE;
2256 }
2257 reserved_host = TRUE;
2258 }
2259
2260 /* If a load level above which only messages from reserved hosts are
2261 accepted is set, check the load. For incoming calls via the daemon, the
2262 check is done in the superior process if there are no reserved hosts, to
2263 save a fork. In all cases, the load average will already be available
2264 in a global variable at this point. */
2265
2266 if (smtp_load_reserve >= 0 &&
2267 load_average > smtp_load_reserve &&
2268 !reserved_host &&
2269 verify_check_host(&smtp_reserve_hosts) != OK)
2270 {
2271 log_write(L_connection_reject,
2272 LOG_MAIN, "temporarily refused connection from %s: not in "
2273 "reserve list and load average = %.2f", host_and_ident(FALSE),
2274 (double)load_average/1000.0);
2275 smtp_printf("421 %s: Too much load; please try again later\r\n",
2276 smtp_active_hostname);
2277 return FALSE;
2278 }
2279
2280 /* Determine whether unqualified senders or recipients are permitted
2281 for this host. Unfortunately, we have to do this every time, in order to
2282 set the flags so that they can be inspected when considering qualifying
2283 addresses in the headers. For a site that permits no qualification, this
2284 won't take long, however. */
2285
2286 allow_unqualified_sender =
2287 verify_check_host(&sender_unqualified_hosts) == OK;
2288
2289 allow_unqualified_recipient =
2290 verify_check_host(&recipient_unqualified_hosts) == OK;
2291
2292 /* Determine whether HELO/EHLO is required for this host. The requirement
2293 can be hard or soft. */
2294
2295 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2296 if (!helo_required)
2297 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2298
2299 /* Determine whether this hosts is permitted to send syntactic junk
2300 after a HELO or EHLO command. */
2301
2302 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2303 }
2304
2305 /* For batch SMTP input we are now done. */
2306
2307 if (smtp_batched_input) return TRUE;
2308
2309 #ifdef EXPERIMENTAL_PROXY
2310 /* If valid Proxy Protocol source is connecting, set up session.
2311 * Failure will not allow any SMTP function other than QUIT. */
2312 proxy_session = FALSE;
2313 proxy_session_failed = FALSE;
2314 if (check_proxy_protocol_host())
2315 {
2316 if (setup_proxy_protocol_host() == FALSE)
2317 {
2318 proxy_session_failed = TRUE;
2319 DEBUG(D_receive)
2320 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2321 }
2322 else
2323 {
2324 sender_host_name = NULL;
2325 (void)host_name_lookup();
2326 host_build_sender_fullhost();
2327 }
2328 }
2329 #endif
2330
2331 /* Run the ACL if it exists */
2332
2333 user_msg = NULL;
2334 if (acl_smtp_connect != NULL)
2335 {
2336 int rc;
2337 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2338 &log_msg);
2339 if (rc != OK)
2340 {
2341 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2342 return FALSE;
2343 }
2344 }
2345
2346 /* Output the initial message for a two-way SMTP connection. It may contain
2347 newlines, which then cause a multi-line response to be given. */
2348
2349 code = US"220"; /* Default status code */
2350 esc = US""; /* Default extended status code */
2351 esclen = 0; /* Length of esc */
2352
2353 if (user_msg == NULL)
2354 {
2355 s = expand_string(smtp_banner);
2356 if (s == NULL)
2357 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2358 "failed: %s", smtp_banner, expand_string_message);
2359 }
2360 else
2361 {
2362 int codelen = 3;
2363 s = user_msg;
2364 smtp_message_code(&code, &codelen, &s, NULL);
2365 if (codelen > 4)
2366 {
2367 esc = code + 4;
2368 esclen = codelen - 4;
2369 }
2370 }
2371
2372 /* Remove any terminating newlines; might as well remove trailing space too */
2373
2374 p = s + Ustrlen(s);
2375 while (p > s && isspace(p[-1])) p--;
2376 *p = 0;
2377
2378 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2379 is all contained in a single IP packet. The original code wrote out the
2380 greeting using several calls to fprint/fputc, and on busy servers this could
2381 cause it to be split over more than one packet - which caused CC:Mail to fall
2382 over when it got the second part of the greeting after sending its first
2383 command. Sigh. To try to avoid this, build the complete greeting message
2384 first, and output it in one fell swoop. This gives a better chance of it
2385 ending up as a single packet. */
2386
2387 ss = store_get(size);
2388 ptr = 0;
2389
2390 p = s;
2391 do /* At least once, in case we have an empty string */
2392 {
2393 int len;
2394 uschar *linebreak = Ustrchr(p, '\n');
2395 ss = string_cat(ss, &size, &ptr, code, 3);
2396 if (linebreak == NULL)
2397 {
2398 len = Ustrlen(p);
2399 ss = string_cat(ss, &size, &ptr, US" ", 1);
2400 }
2401 else
2402 {
2403 len = linebreak - p;
2404 ss = string_cat(ss, &size, &ptr, US"-", 1);
2405 }
2406 ss = string_cat(ss, &size, &ptr, esc, esclen);
2407 ss = string_cat(ss, &size, &ptr, p, len);
2408 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
2409 p += len;
2410 if (linebreak != NULL) p++;
2411 }
2412 while (*p != 0);
2413
2414 ss[ptr] = 0; /* string_cat leaves room for this */
2415
2416 /* Before we write the banner, check that there is no input pending, unless
2417 this synchronisation check is disabled. */
2418
2419 if (!check_sync())
2420 {
2421 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2422 "synchronization error (input sent without waiting for greeting): "
2423 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2424 string_printing(smtp_inptr));
2425 smtp_printf("554 SMTP synchronization error\r\n");
2426 return FALSE;
2427 }
2428
2429 /* Now output the banner */
2430
2431 smtp_printf("%s", ss);
2432 return TRUE;
2433 }
2434
2435
2436
2437
2438
2439 /*************************************************
2440 * Handle SMTP syntax and protocol errors *
2441 *************************************************/
2442
2443 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2444 to do so. Then transmit the error response. The return value depends on the
2445 number of syntax and protocol errors in this SMTP session.
2446
2447 Arguments:
2448 type error type, given as a log flag bit
2449 code response code; <= 0 means don't send a response
2450 data data to reflect in the response (can be NULL)
2451 errmess the error message
2452
2453 Returns: -1 limit of syntax/protocol errors NOT exceeded
2454 +1 limit of syntax/protocol errors IS exceeded
2455
2456 These values fit in with the values of the "done" variable in the main
2457 processing loop in smtp_setup_msg(). */
2458
2459 static int
2460 synprot_error(int type, int code, uschar *data, uschar *errmess)
2461 {
2462 int yield = -1;
2463
2464 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2465 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2466 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2467
2468 if (++synprot_error_count > smtp_max_synprot_errors)
2469 {
2470 yield = 1;
2471 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2472 "syntax or protocol errors (last command was \"%s\")",
2473 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2474 }
2475
2476 if (code > 0)
2477 {
2478 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2479 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2480 if (yield == 1)
2481 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2482 }
2483
2484 return yield;
2485 }
2486
2487
2488
2489
2490 /*************************************************
2491 * Log incomplete transactions *
2492 *************************************************/
2493
2494 /* This function is called after a transaction has been aborted by RSET, QUIT,
2495 connection drops or other errors. It logs the envelope information received
2496 so far in order to preserve address verification attempts.
2497
2498 Argument: string to indicate what aborted the transaction
2499 Returns: nothing
2500 */
2501
2502 static void
2503 incomplete_transaction_log(uschar *what)
2504 {
2505 if (sender_address == NULL || /* No transaction in progress */
2506 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
2507 ) return;
2508
2509 /* Build list of recipients for logging */
2510
2511 if (recipients_count > 0)
2512 {
2513 int i;
2514 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2515 for (i = 0; i < recipients_count; i++)
2516 raw_recipients[i] = recipients_list[i].address;
2517 raw_recipients_count = recipients_count;
2518 }
2519
2520 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2521 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2522 }
2523
2524
2525
2526
2527 /*************************************************
2528 * Send SMTP response, possibly multiline *
2529 *************************************************/
2530
2531 /* There are, it seems, broken clients out there that cannot handle multiline
2532 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2533 output nothing for non-final calls, and only the first line for anything else.
2534
2535 Arguments:
2536 code SMTP code, may involve extended status codes
2537 codelen length of smtp code; if > 4 there's an ESC
2538 final FALSE if the last line isn't the final line
2539 msg message text, possibly containing newlines
2540
2541 Returns: nothing
2542 */
2543
2544 void
2545 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2546 {
2547 int esclen = 0;
2548 uschar *esc = US"";
2549
2550 if (!final && no_multiline_responses) return;
2551
2552 if (codelen > 4)
2553 {
2554 esc = code + 4;
2555 esclen = codelen - 4;
2556 }
2557
2558 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2559 have had the same. Note: this code is also present in smtp_printf(). It would
2560 be tidier to have it only in one place, but when it was added, it was easier to
2561 do it that way, so as not to have to mess with the code for the RCPT command,
2562 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2563
2564 if (rcpt_in_progress)
2565 {
2566 if (rcpt_smtp_response == NULL)
2567 rcpt_smtp_response = string_copy(msg);
2568 else if (rcpt_smtp_response_same &&
2569 Ustrcmp(rcpt_smtp_response, msg) != 0)
2570 rcpt_smtp_response_same = FALSE;
2571 rcpt_in_progress = FALSE;
2572 }
2573
2574 /* Not output the message, splitting it up into multiple lines if necessary. */
2575
2576 for (;;)
2577 {
2578 uschar *nl = Ustrchr(msg, '\n');
2579 if (nl == NULL)
2580 {
2581 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2582 return;
2583 }
2584 else if (nl[1] == 0 || no_multiline_responses)
2585 {
2586 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2587 (int)(nl - msg), msg);
2588 return;
2589 }
2590 else
2591 {
2592 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2593 msg = nl + 1;
2594 while (isspace(*msg)) msg++;
2595 }
2596 }
2597 }
2598
2599
2600
2601
2602 /*************************************************
2603 * Parse user SMTP message *
2604 *************************************************/
2605
2606 /* This function allows for user messages overriding the response code details
2607 by providing a suitable response code string at the start of the message
2608 user_msg. Check the message for starting with a response code and optionally an
2609 extended status code. If found, check that the first digit is valid, and if so,
2610 change the code pointer and length to use the replacement. An invalid code
2611 causes a panic log; in this case, if the log messages is the same as the user
2612 message, we must also adjust the value of the log message to show the code that
2613 is actually going to be used (the original one).
2614
2615 This function is global because it is called from receive.c as well as within
2616 this module.
2617
2618 Note that the code length returned includes the terminating whitespace
2619 character, which is always included in the regex match.
2620
2621 Arguments:
2622 code SMTP code, may involve extended status codes
2623 codelen length of smtp code; if > 4 there's an ESC
2624 msg message text
2625 log_msg optional log message, to be adjusted with the new SMTP code
2626
2627 Returns: nothing
2628 */
2629
2630 void
2631 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2632 {
2633 int n;
2634 int ovector[3];
2635
2636 if (msg == NULL || *msg == NULL) return;
2637
2638 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2639 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2640 if (n < 0) return;
2641
2642 if ((*msg)[0] != (*code)[0])
2643 {
2644 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2645 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2646 if (log_msg != NULL && *log_msg == *msg)
2647 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2648 }
2649 else
2650 {
2651 *code = *msg;
2652 *codelen = ovector[1]; /* Includes final space */
2653 }
2654 *msg += ovector[1]; /* Chop the code off the message */
2655 return;
2656 }
2657
2658
2659
2660
2661 /*************************************************
2662 * Handle an ACL failure *
2663 *************************************************/
2664
2665 /* This function is called when acl_check() fails. As well as calls from within
2666 this module, it is called from receive.c for an ACL after DATA. It sorts out
2667 logging the incident, and sets up the error response. A message containing
2668 newlines is turned into a multiline SMTP response, but for logging, only the
2669 first line is used.
2670
2671 There's a table of default permanent failure response codes to use in
2672 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2673 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2674 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2675 state, because there are broken clients that try VRFY before RCPT. A 5xx
2676 response should be given only when the address is positively known to be
2677 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2678 503.
2679
2680 From Exim 4.63, it is possible to override the response code details by
2681 providing a suitable response code string at the start of the message provided
2682 in user_msg. The code's first digit is checked for validity.
2683
2684 Arguments:
2685 where where the ACL was called from
2686 rc the failure code
2687 user_msg a message that can be included in an SMTP response
2688 log_msg a message for logging
2689
2690 Returns: 0 in most cases
2691 2 if the failure code was FAIL_DROP, in which case the
2692 SMTP connection should be dropped (this value fits with the
2693 "done" variable in smtp_setup_msg() below)
2694 */
2695
2696 int
2697 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2698 {
2699 BOOL drop = rc == FAIL_DROP;
2700 int codelen = 3;
2701 uschar *smtp_code;
2702 uschar *lognl;
2703 uschar *sender_info = US"";
2704 uschar *what =
2705 #ifdef WITH_CONTENT_SCAN
2706 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2707 #endif
2708 (where == ACL_WHERE_PREDATA)? US"DATA" :
2709 (where == ACL_WHERE_DATA)? US"after DATA" :
2710 #ifndef DISABLE_PRDR
2711 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2712 #endif
2713 (smtp_cmd_data == NULL)?
2714 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2715 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2716
2717 if (drop) rc = FAIL;
2718
2719 /* Set the default SMTP code, and allow a user message to change it. */
2720
2721 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2722 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2723
2724 /* We used to have sender_address here; however, there was a bug that was not
2725 updating sender_address after a rewrite during a verify. When this bug was
2726 fixed, sender_address at this point became the rewritten address. I'm not sure
2727 this is what should be logged, so I've changed to logging the unrewritten
2728 address to retain backward compatibility. */
2729
2730 #ifndef WITH_CONTENT_SCAN
2731 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2732 #else
2733 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2734 #endif
2735 {
2736 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2737 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2738 sender_host_authenticated ? US" A=" : US"",
2739 sender_host_authenticated ? sender_host_authenticated : US"",
2740 sender_host_authenticated && authenticated_id ? US":" : US"",
2741 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2742 );
2743 }
2744
2745 /* If there's been a sender verification failure with a specific message, and
2746 we have not sent a response about it yet, do so now, as a preliminary line for
2747 failures, but not defers. However, always log it for defer, and log it for fail
2748 unless the sender_verify_fail log selector has been turned off. */
2749
2750 if (sender_verified_failed != NULL &&
2751 !testflag(sender_verified_failed, af_sverify_told))
2752 {
2753 BOOL save_rcpt_in_progress = rcpt_in_progress;
2754 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2755
2756 setflag(sender_verified_failed, af_sverify_told);
2757
2758 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2759 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2760 host_and_ident(TRUE),
2761 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2762 sender_verified_failed->address,
2763 (sender_verified_failed->message == NULL)? US"" :
2764 string_sprintf(": %s", sender_verified_failed->message));
2765
2766 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2767 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2768 testflag(sender_verified_failed, af_verify_pmfail)?
2769 "Postmaster verification failed while checking <%s>\n%s\n"
2770 "Several RFCs state that you are required to have a postmaster\n"
2771 "mailbox for each mail domain. This host does not accept mail\n"
2772 "from domains whose servers reject the postmaster address."
2773 :
2774 testflag(sender_verified_failed, af_verify_nsfail)?
2775 "Callback setup failed while verifying <%s>\n%s\n"
2776 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2777 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2778 "RFC requirements, and stops you from receiving standard bounce\n"
2779 "messages. This host does not accept mail from domains whose servers\n"
2780 "refuse bounces."
2781 :
2782 "Verification failed for <%s>\n%s",
2783 sender_verified_failed->address,
2784 sender_verified_failed->user_message));
2785
2786 rcpt_in_progress = save_rcpt_in_progress;
2787 }
2788
2789 /* Sort out text for logging */
2790
2791 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2792 lognl = Ustrchr(log_msg, '\n');
2793 if (lognl != NULL) *lognl = 0;
2794
2795 /* Send permanent failure response to the command, but the code used isn't
2796 always a 5xx one - see comments at the start of this function. If the original
2797 rc was FAIL_DROP we drop the connection and yield 2. */
2798
2799 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2800 US"Administrative prohibition" : user_msg);
2801
2802 /* Send temporary failure response to the command. Don't give any details,
2803 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2804 verb, and for a header verify when smtp_return_error_details is set.
2805
2806 This conditional logic is all somewhat of a mess because of the odd
2807 interactions between temp_details and return_error_details. One day it should
2808 be re-implemented in a tidier fashion. */
2809
2810 else
2811 {
2812 if (acl_temp_details && user_msg != NULL)
2813 {
2814 if (smtp_return_error_details &&
2815 sender_verified_failed != NULL &&
2816 sender_verified_failed->message != NULL)
2817 {
2818 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2819 }
2820 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2821 }
2822 else
2823 smtp_respond(smtp_code, codelen, TRUE,
2824 US"Temporary local problem - please try later");
2825 }
2826
2827 /* Log the incident to the logs that are specified by log_reject_target
2828 (default main, reject). This can be empty to suppress logging of rejections. If
2829 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2830 is closing if required and return 2. */
2831
2832 if (log_reject_target != 0)
2833 {
2834 #ifdef SUPPORT_TLS
2835 uschar * s = s_tlslog(NULL, NULL, NULL);
2836 if (!s) s = US"";
2837 #else
2838 uschar * s = US"";
2839 #endif
2840 log_write(0, log_reject_target, "%s%s %s%srejected %s%s",
2841 host_and_ident(TRUE), s,
2842 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2843 }
2844
2845 if (!drop) return 0;
2846
2847 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2848 smtp_get_connection_info());
2849
2850 /* Run the not-quit ACL, but without any custom messages. This should not be a
2851 problem, because we get here only if some other ACL has issued "drop", and
2852 in that case, *its* custom messages will have been used above. */
2853
2854 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2855 return 2;
2856 }
2857
2858
2859
2860
2861 /*************************************************
2862 * Handle SMTP exit when QUIT is not given *
2863 *************************************************/
2864
2865 /* This function provides a logging/statistics hook for when an SMTP connection
2866 is dropped on the floor or the other end goes away. It's a global function
2867 because it's called from receive.c as well as this module. As well as running
2868 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2869 response, either with a custom message from the ACL, or using a default. There
2870 is one case, however, when no message is output - after "drop". In that case,
2871 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2872 passed to this function.
2873
2874 In case things go wrong while processing this function, causing an error that
2875 may re-enter this funtion, there is a recursion check.
2876
2877 Arguments:
2878 reason What $smtp_notquit_reason will be set to in the ACL;
2879 if NULL, the ACL is not run
2880 code The error code to return as part of the response
2881 defaultrespond The default message if there's no user_msg
2882
2883 Returns: Nothing
2884 */
2885
2886 void
2887 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2888 {
2889 int rc;
2890 uschar *user_msg = NULL;
2891 uschar *log_msg = NULL;
2892
2893 /* Check for recursive acll */
2894
2895 if (smtp_exit_function_called)
2896 {
2897 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2898 reason);
2899 return;
2900 }
2901 smtp_exit_function_called = TRUE;
2902
2903 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2904
2905 if (acl_smtp_notquit != NULL && reason != NULL)
2906 {
2907 smtp_notquit_reason = reason;
2908 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2909 &log_msg);
2910 if (rc == ERROR)
2911 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2912 log_msg);
2913 }
2914
2915 /* Write an SMTP response if we are expected to give one. As the default
2916 responses are all internal, they should always fit in the buffer, but code a
2917 warning, just in case. Note that string_vformat() still leaves a complete
2918 string, even if it is incomplete. */
2919
2920 if (code != NULL && defaultrespond != NULL)
2921 {
2922 if (user_msg == NULL)
2923 {
2924 uschar buffer[128];
2925 va_list ap;
2926 va_start(ap, defaultrespond);
2927 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2928 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2929 smtp_printf("%s %s\r\n", code, buffer);
2930 va_end(ap);
2931 }
2932 else
2933 smtp_respond(code, 3, TRUE, user_msg);
2934 mac_smtp_fflush();
2935 }
2936 }
2937
2938
2939
2940
2941 /*************************************************
2942 * Verify HELO argument *
2943 *************************************************/
2944
2945 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2946 matched. It is also called from ACL processing if verify = helo is used and
2947 verification was not previously tried (i.e. helo_try_verify_hosts was not
2948 matched). The result of its processing is to set helo_verified and
2949 helo_verify_failed. These variables should both be FALSE for this function to
2950 be called.
2951
2952 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2953 for IPv6 ::ffff: literals.
2954
2955 Argument: none
2956 Returns: TRUE if testing was completed;
2957 FALSE on a temporary failure
2958 */
2959
2960 BOOL
2961 smtp_verify_helo(void)
2962 {
2963 BOOL yield = TRUE;
2964
2965 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2966 sender_helo_name);
2967
2968 if (sender_helo_name == NULL)
2969 {
2970 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2971 }
2972
2973 /* Deal with the case of -bs without an IP address */
2974
2975 else if (sender_host_address == NULL)
2976 {
2977 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2978 helo_verified = TRUE;
2979 }
2980
2981 /* Deal with the more common case when there is a sending IP address */
2982
2983 else if (sender_helo_name[0] == '[')
2984 {
2985 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2986 Ustrlen(sender_host_address)) == 0;
2987
2988 #if HAVE_IPV6
2989 if (!helo_verified)
2990 {
2991 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2992 helo_verified = Ustrncmp(sender_helo_name + 1,
2993 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2994 }
2995 #endif
2996
2997 HDEBUG(D_receive)
2998 { if (helo_verified) debug_printf("matched host address\n"); }
2999 }
3000
3001 /* Do a reverse lookup if one hasn't already given a positive or negative
3002 response. If that fails, or the name doesn't match, try checking with a forward
3003 lookup. */
3004
3005 else
3006 {
3007 if (sender_host_name == NULL && !host_lookup_failed)
3008 yield = host_name_lookup() != DEFER;
3009
3010 /* If a host name is known, check it and all its aliases. */
3011
3012 if (sender_host_name)
3013 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3014 {
3015 sender_helo_dnssec = sender_host_dnssec;
3016 HDEBUG(D_receive) debug_printf("matched host name\n");
3017 }
3018 else
3019 {
3020 uschar **aliases = sender_host_aliases;
3021 while (*aliases)
3022 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3023 {
3024 sender_helo_dnssec = sender_host_dnssec;
3025 break;
3026 }
3027
3028 HDEBUG(D_receive) if (helo_verified)
3029 debug_printf("matched alias %s\n", *(--aliases));
3030 }
3031
3032 /* Final attempt: try a forward lookup of the helo name */
3033
3034 if (!helo_verified)
3035 {
3036 int rc;
3037 host_item h;
3038 dnssec_domains d;
3039 host_item *hh;
3040
3041 h.name = sender_helo_name;
3042 h.address = NULL;
3043 h.mx = MX_NONE;
3044 h.next = NULL;
3045 d.request = US"*";
3046 d.require = US"";
3047
3048 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3049 sender_helo_name);
3050 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3051 NULL, NULL, NULL, &d, NULL, NULL);
3052 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3053 for (hh = &h; hh; hh = hh->next)
3054 if (Ustrcmp(hh->address, sender_host_address) == 0)
3055 {
3056 helo_verified = TRUE;
3057 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3058 HDEBUG(D_receive)
3059 {
3060 debug_printf("IP address for %s matches calling address\n"
3061 "Forward DNS security status: %sverified\n",
3062 sender_helo_name, sender_helo_dnssec ? "" : "un");
3063 }
3064 break;
3065 }
3066 }
3067 }
3068
3069 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3070 return yield;
3071 }
3072
3073
3074
3075
3076 /*************************************************
3077 * Send user response message *
3078 *************************************************/
3079
3080 /* This function is passed a default response code and a user message. It calls
3081 smtp_message_code() to check and possibly modify the response code, and then
3082 calls smtp_respond() to transmit the response. I put this into a function
3083 just to avoid a lot of repetition.
3084
3085 Arguments:
3086 code the response code
3087 user_msg the user message
3088
3089 Returns: nothing
3090 */
3091
3092 static void
3093 smtp_user_msg(uschar *code, uschar *user_msg)
3094 {
3095 int len = 3;
3096 smtp_message_code(&code, &len, &user_msg, NULL);
3097 smtp_respond(code, len, TRUE, user_msg);
3098 }
3099
3100
3101
3102 static int
3103 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3104 {
3105 const uschar *set_id = NULL;
3106 int rc, i;
3107
3108 /* Run the checking code, passing the remainder of the command line as
3109 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3110 it as the only set numerical variable. The authenticator may set $auth<n>
3111 and also set other numeric variables. The $auth<n> variables are preferred
3112 nowadays; the numerical variables remain for backwards compatibility.
3113
3114 Afterwards, have a go at expanding the set_id string, even if
3115 authentication failed - for bad passwords it can be useful to log the
3116 userid. On success, require set_id to expand and exist, and put it in
3117 authenticated_id. Save this in permanent store, as the working store gets
3118 reset at HELO, RSET, etc. */
3119
3120 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3121 expand_nmax = 0;
3122 expand_nlength[0] = 0; /* $0 contains nothing */
3123
3124 rc = (au->info->servercode)(au, smtp_cmd_data);
3125 if (au->set_id) set_id = expand_string(au->set_id);
3126 expand_nmax = -1; /* Reset numeric variables */
3127 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3128
3129 /* The value of authenticated_id is stored in the spool file and printed in
3130 log lines. It must not contain binary zeros or newline characters. In
3131 normal use, it never will, but when playing around or testing, this error
3132 can (did) happen. To guard against this, ensure that the id contains only
3133 printing characters. */
3134
3135 if (set_id) set_id = string_printing(set_id);
3136
3137 /* For the non-OK cases, set up additional logging data if set_id
3138 is not empty. */
3139
3140 if (rc != OK)
3141 set_id = set_id && *set_id
3142 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3143
3144 /* Switch on the result */
3145
3146 switch(rc)
3147 {
3148 case OK:
3149 if (!au->set_id || set_id) /* Complete success */
3150 {
3151 if (set_id) authenticated_id = string_copy_malloc(set_id);
3152 sender_host_authenticated = au->name;
3153 authentication_failed = FALSE;
3154 authenticated_fail_id = NULL; /* Impossible to already be set? */
3155
3156 received_protocol =
3157 (sender_host_address ? protocols : protocols_local)
3158 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3159 *s = *ss = US"235 Authentication succeeded";
3160 authenticated_by = au;
3161 break;
3162 }
3163
3164 /* Authentication succeeded, but we failed to expand the set_id string.
3165 Treat this as a temporary error. */
3166
3167 auth_defer_msg = expand_string_message;
3168 /* Fall through */
3169
3170 case DEFER:
3171 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3172 *s = string_sprintf("435 Unable to authenticate at present%s",
3173 auth_defer_user_msg);
3174 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3175 set_id, auth_defer_msg);
3176 break;
3177
3178 case BAD64:
3179 *s = *ss = US"501 Invalid base64 data";
3180 break;
3181
3182 case CANCELLED:
3183 *s = *ss = US"501 Authentication cancelled";
3184 break;
3185
3186 case UNEXPECTED:
3187 *s = *ss = US"553 Initial data not expected";
3188 break;
3189
3190 case FAIL:
3191 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3192 *s = US"535 Incorrect authentication data";
3193 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3194 break;
3195
3196 default:
3197 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3198 *s = US"435 Internal error";
3199 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3200 "check", set_id, rc);
3201 break;
3202 }
3203
3204 return rc;
3205 }
3206
3207
3208
3209 /*************************************************
3210 * Initialize for SMTP incoming message *
3211 *************************************************/
3212
3213 /* This function conducts the initial dialogue at the start of an incoming SMTP
3214 message, and builds a list of recipients. However, if the incoming message
3215 is part of a batch (-bS option) a separate function is called since it would
3216 be messy having tests splattered about all over this function. This function
3217 therefore handles the case where interaction is occurring. The input and output
3218 files are set up in smtp_in and smtp_out.
3219
3220 The global recipients_list is set to point to a vector of recipient_item
3221 blocks, whose number is given by recipients_count. This is extended by the
3222 receive_add_recipient() function. The global variable sender_address is set to
3223 the sender's address. The yield is +1 if a message has been successfully
3224 started, 0 if a QUIT command was encountered or the connection was refused from
3225 the particular host, or -1 if the connection was lost.
3226
3227 Argument: none
3228
3229 Returns: > 0 message successfully started (reached DATA)
3230 = 0 QUIT read or end of file reached or call refused
3231 < 0 lost connection
3232 */
3233
3234 int
3235 smtp_setup_msg(void)
3236 {
3237 int done = 0;
3238 BOOL toomany = FALSE;
3239 BOOL discarded = FALSE;
3240 BOOL last_was_rej_mail = FALSE;
3241 BOOL last_was_rcpt = FALSE;
3242 void *reset_point = store_get(0);
3243
3244 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3245
3246 /* Reset for start of new message. We allow one RSET not to be counted as a
3247 nonmail command, for those MTAs that insist on sending it between every
3248 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3249 TLS between messages (an Exim client may do this if it has messages queued up
3250 for the host). Note: we do NOT reset AUTH at this point. */
3251
3252 smtp_reset(reset_point);
3253 message_ended = END_NOTSTARTED;
3254
3255 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3256 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3257 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3258 #ifdef SUPPORT_TLS
3259 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3260 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3261 #endif
3262
3263 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3264
3265 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3266
3267 /* Batched SMTP is handled in a different function. */
3268
3269 if (smtp_batched_input) return smtp_setup_batch_msg();
3270
3271 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3272 value. The values are 2 larger than the required yield of the function. */
3273
3274 while (done <= 0)
3275 {
3276 const uschar **argv;
3277 uschar *etrn_command;
3278 uschar *etrn_serialize_key;
3279 uschar *errmess;
3280 uschar *log_msg, *smtp_code;
3281 uschar *user_msg = NULL;
3282 uschar *recipient = NULL;
3283 uschar *hello = NULL;
3284 uschar *s, *ss;
3285 BOOL was_rej_mail = FALSE;
3286 BOOL was_rcpt = FALSE;
3287 void (*oldsignal)(int);
3288 pid_t pid;
3289 int start, end, sender_domain, recipient_domain;
3290 int ptr, size, rc;
3291 int c, i;
3292 auth_instance *au;
3293 uschar *orcpt = NULL;
3294 int flags;
3295
3296 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3297 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3298 if ( tls_in.active >= 0
3299 && tls_in.peercert
3300 && tls_in.certificate_verified
3301 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3302 )
3303 {
3304 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3305 if (acl_smtp_auth)
3306 {
3307 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
3308 if (rc != OK)
3309 {
3310 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3311 continue;
3312 }
3313 }
3314
3315 for (au = auths; au; au = au->next)
3316 if (strcmpic(US"tls", au->driver_name) == 0)
3317 {
3318 smtp_cmd_data = NULL;
3319
3320 if ((c = smtp_in_auth(au, &s, &ss)) != OK)
3321 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3322 au->name, host_and_ident(FALSE), ss);
3323 else
3324 DEBUG(D_auth) debug_printf("tls auth succeeded\n");
3325
3326 break;
3327 }
3328 }
3329 #endif
3330
3331 switch(smtp_read_command(TRUE))
3332 {
3333 /* The AUTH command is not permitted to occur inside a transaction, and may
3334 occur successfully only once per connection. Actually, that isn't quite
3335 true. When TLS is started, all previous information about a connection must
3336 be discarded, so a new AUTH is permitted at that time.
3337
3338 AUTH may only be used when it has been advertised. However, it seems that
3339 there are clients that send AUTH when it hasn't been advertised, some of
3340 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3341 So there's a get-out that allows this to happen.
3342
3343 AUTH is initially labelled as a "nonmail command" so that one occurrence
3344 doesn't get counted. We change the label here so that multiple failing
3345 AUTHS will eventually hit the nonmail threshold. */
3346
3347 case AUTH_CMD:
3348 HAD(SCH_AUTH);
3349 authentication_failed = TRUE;
3350 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3351
3352 if (!auth_advertised && !allow_auth_unadvertised)
3353 {
3354 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3355 US"AUTH command used when not advertised");
3356 break;
3357 }
3358 if (sender_host_authenticated)
3359 {
3360 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3361 US"already authenticated");
3362 break;
3363 }
3364 if (sender_address)
3365 {
3366 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3367 US"not permitted in mail transaction");
3368 break;
3369 }
3370
3371 /* Check the ACL */
3372
3373 if (acl_smtp_auth)
3374 {
3375 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
3376 if (rc != OK)
3377 {
3378 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3379 break;
3380 }
3381 }
3382
3383 /* Find the name of the requested authentication mechanism. */
3384
3385 s = smtp_cmd_data;
3386 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3387 {
3388 if (!isalnum(c) && c != '-' && c != '_')
3389 {
3390 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3391 US"invalid character in authentication mechanism name");
3392 goto COMMAND_LOOP;
3393 }
3394 smtp_cmd_data++;
3395 }
3396
3397 /* If not at the end of the line, we must be at white space. Terminate the
3398 name and move the pointer on to any data that may be present. */
3399
3400 if (*smtp_cmd_data != 0)
3401 {
3402 *smtp_cmd_data++ = 0;
3403 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3404 }
3405
3406 /* Search for an authentication mechanism which is configured for use
3407 as a server and which has been advertised (unless, sigh, allow_auth_
3408 unadvertised is set). */
3409
3410 for (au = auths; au; au = au->next)
3411 if (strcmpic(s, au->public_name) == 0 && au->server &&
3412 (au->advertised || allow_auth_unadvertised))
3413 break;
3414
3415 if (au)
3416 {
3417 c = smtp_in_auth(au, &s, &ss);
3418
3419 smtp_printf("%s\r\n", s);
3420 if (c != OK)
3421 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3422 au->name, host_and_ident(FALSE), ss);
3423 }
3424 else
3425 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3426 string_sprintf("%s authentication mechanism not supported", s));
3427
3428 break; /* AUTH_CMD */
3429
3430 /* The HELO/EHLO commands are permitted to appear in the middle of a
3431 session as well as at the beginning. They have the effect of a reset in
3432 addition to their other functions. Their absence at the start cannot be
3433 taken to be an error.
3434
3435 RFC 2821 says:
3436
3437 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3438 or 502 failure replies MUST be returned as appropriate. The SMTP
3439 server MUST stay in the same state after transmitting these replies
3440 that it was in before the EHLO was received.
3441
3442 Therefore, we do not do the reset until after checking the command for
3443 acceptability. This change was made for Exim release 4.11. Previously
3444 it did the reset first. */
3445
3446 case HELO_CMD:
3447 HAD(SCH_HELO);
3448 hello = US"HELO";
3449 esmtp = FALSE;
3450 goto HELO_EHLO;
3451
3452 case EHLO_CMD:
3453 HAD(SCH_EHLO);
3454 hello = US"EHLO";
3455 esmtp = TRUE;
3456
3457 HELO_EHLO: /* Common code for HELO and EHLO */
3458 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3459 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3460
3461 /* Reject the HELO if its argument was invalid or non-existent. A
3462 successful check causes the argument to be saved in malloc store. */
3463
3464 if (!check_helo(smtp_cmd_data))
3465 {
3466 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3467
3468 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3469 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3470 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3471 string_printing(smtp_cmd_argument));
3472
3473 if (++synprot_error_count > smtp_max_synprot_errors)
3474 {
3475 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3476 "syntax or protocol errors (last command was \"%s\")",
3477 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3478 done = 1;
3479 }
3480
3481 break;
3482 }
3483
3484 /* If sender_host_unknown is true, we have got here via the -bs interface,
3485 not called from inetd. Otherwise, we are running an IP connection and the
3486 host address will be set. If the helo name is the primary name of this
3487 host and we haven't done a reverse lookup, force one now. If helo_required
3488 is set, ensure that the HELO name matches the actual host. If helo_verify
3489 is set, do the same check, but softly. */
3490
3491 if (!sender_host_unknown)
3492 {
3493 BOOL old_helo_verified = helo_verified;
3494 uschar *p = smtp_cmd_data;
3495
3496 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3497 *p = 0;
3498
3499 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3500 because otherwise the log can be confusing. */
3501
3502 if (sender_host_name == NULL &&
3503 (deliver_domain = sender_helo_name, /* set $domain */
3504 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3505 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3506 (void)host_name_lookup();
3507
3508 /* Rebuild the fullhost info to include the HELO name (and the real name
3509 if it was looked up.) */
3510
3511 host_build_sender_fullhost(); /* Rebuild */
3512 set_process_info("handling%s incoming connection from %s",
3513 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3514
3515 /* Verify if configured. This doesn't give much security, but it does
3516 make some people happy to be able to do it. If helo_required is set,
3517 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3518 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3519 now obsolescent, since the verification can now be requested selectively
3520 at ACL time. */
3521
3522 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
3523 if (helo_required || helo_verify)
3524 {
3525 BOOL tempfail = !smtp_verify_helo();
3526 if (!helo_verified)
3527 {
3528 if (helo_required)
3529 {
3530 smtp_printf("%d %s argument does not match calling host\r\n",
3531 tempfail? 451 : 550, hello);
3532 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3533 tempfail? "temporarily " : "",
3534 hello, sender_helo_name, host_and_ident(FALSE));
3535 helo_verified = old_helo_verified;
3536 break; /* End of HELO/EHLO processing */
3537 }
3538 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3539 "helo_try_verify_hosts\n", hello);
3540 }
3541 }
3542 }
3543
3544 #ifdef EXPERIMENTAL_SPF
3545 /* set up SPF context */
3546 spf_init(sender_helo_name, sender_host_address);
3547 #endif
3548
3549 /* Apply an ACL check if one is defined; afterwards, recheck
3550 synchronization in case the client started sending in a delay. */
3551
3552 if (acl_smtp_helo != NULL)
3553 {
3554 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
3555 if (rc != OK)
3556 {
3557 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3558 sender_helo_name = NULL;
3559 host_build_sender_fullhost(); /* Rebuild */
3560 break;
3561 }
3562 else if (!check_sync()) goto SYNC_FAILURE;
3563 }
3564
3565 /* Generate an OK reply. The default string includes the ident if present,
3566 and also the IP address if present. Reflecting back the ident is intended
3567 as a deterrent to mail forgers. For maximum efficiency, and also because
3568 some broken systems expect each response to be in a single packet, arrange
3569 that the entire reply is sent in one write(). */
3570
3571 auth_advertised = FALSE;
3572 pipelining_advertised = FALSE;
3573 #ifdef SUPPORT_TLS
3574 tls_advertised = FALSE;
3575 #endif
3576 dsn_advertised = FALSE;
3577 #ifdef EXPERIMENTAL_INTERNATIONAL
3578 smtputf8_advertised = FALSE;
3579 #endif
3580
3581 smtp_code = US"250 "; /* Default response code plus space*/
3582 if (user_msg == NULL)
3583 {
3584 s = string_sprintf("%.3s %s Hello %s%s%s",
3585 smtp_code,
3586 smtp_active_hostname,
3587 (sender_ident == NULL)? US"" : sender_ident,
3588 (sender_ident == NULL)? US"" : US" at ",
3589 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3590
3591 ptr = Ustrlen(s);
3592 size = ptr + 1;
3593
3594 if (sender_host_address != NULL)
3595 {
3596 s = string_cat(s, &size, &ptr, US" [", 2);
3597 s = string_cat(s, &size, &ptr, sender_host_address,
3598 Ustrlen(sender_host_address));
3599 s = string_cat(s, &size, &ptr, US"]", 1);
3600 }
3601 }
3602
3603 /* A user-supplied EHLO greeting may not contain more than one line. Note
3604 that the code returned by smtp_message_code() includes the terminating
3605 whitespace character. */
3606
3607 else
3608 {
3609 char *ss;
3610 int codelen = 4;
3611 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3612 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3613 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3614 {
3615 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3616 "newlines: message truncated: %s", string_printing(s));
3617 *ss = 0;
3618 }
3619 ptr = Ustrlen(s);
3620 size = ptr + 1;
3621 }
3622
3623 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3624
3625 /* If we received EHLO, we must create a multiline response which includes
3626 the functions supported. */
3627
3628 if (esmtp)
3629 {
3630 s[3] = '-';
3631
3632 /* I'm not entirely happy with this, as an MTA is supposed to check
3633 that it has enough room to accept a message of maximum size before
3634 it sends this. However, there seems little point in not sending it.
3635 The actual size check happens later at MAIL FROM time. By postponing it
3636 till then, VRFY and EXPN can be used after EHLO when space is short. */
3637
3638 if (thismessage_size_limit > 0)
3639 {
3640 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3641 thismessage_size_limit);
3642 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3643 }
3644 else
3645 {
3646 s = string_cat(s, &size, &ptr, smtp_code, 3);
3647 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3648 }
3649
3650 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3651 clean; if it has an 8-bit character in its hand, it just sends it. It
3652 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3653 However, some users want this option simply in order to stop MUAs
3654 mangling messages that contain top-bit-set characters. It is therefore
3655 provided as an option. */
3656
3657 if (accept_8bitmime)
3658 {
3659 s = string_cat(s, &size, &ptr, smtp_code, 3);
3660 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3661 }
3662
3663 /* Advertise DSN support if configured to do so. */
3664 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
3665 {
3666 s = string_cat(s, &size, &ptr, smtp_code, 3);
3667 s = string_cat(s, &size, &ptr, US"-DSN\r\n", 6);
3668 dsn_advertised = TRUE;
3669 }
3670
3671 /* Advertise ETRN if there's an ACL checking whether a host is
3672 permitted to issue it; a check is made when any host actually tries. */
3673
3674 if (acl_smtp_etrn != NULL)
3675 {
3676 s = string_cat(s, &size, &ptr, smtp_code, 3);
3677 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3678 }
3679
3680 /* Advertise EXPN if there's an ACL checking whether a host is
3681 permitted to issue it; a check is made when any host actually tries. */
3682
3683 if (acl_smtp_expn != NULL)
3684 {
3685 s = string_cat(s, &size, &ptr, smtp_code, 3);
3686 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3687 }
3688
3689 /* Exim is quite happy with pipelining, so let the other end know that
3690 it is safe to use it, unless advertising is disabled. */
3691
3692 if (pipelining_enable &&
3693 verify_check_host(&pipelining_advertise_hosts) == OK)
3694 {
3695 s = string_cat(s, &size, &ptr, smtp_code, 3);
3696 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3697 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3698 pipelining_advertised = TRUE;
3699 }
3700
3701
3702 /* If any server authentication mechanisms are configured, advertise
3703 them if the current host is in auth_advertise_hosts. The problem with
3704 advertising always is that some clients then require users to
3705 authenticate (and aren't configurable otherwise) even though it may not
3706 be necessary (e.g. if the host is in host_accept_relay).
3707
3708 RFC 2222 states that SASL mechanism names contain only upper case
3709 letters, so output the names in upper case, though we actually recognize
3710 them in either case in the AUTH command. */
3711
3712 if ( auths
3713 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3714 && !sender_host_authenticated
3715 #endif
3716 && verify_check_host(&auth_advertise_hosts) == OK
3717 )
3718 {
3719 auth_instance *au;
3720 BOOL first = TRUE;
3721 for (au = auths; au; au = au->next)
3722 if (au->server && (au->advertise_condition == NULL ||
3723 expand_check_condition(au->advertise_condition, au->name,
3724 US"authenticator")))
3725 {
3726 int saveptr;
3727 if (first)
3728 {
3729 s = string_cat(s, &size, &ptr, smtp_code, 3);
3730 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3731 first = FALSE;
3732 auth_advertised = TRUE;
3733 }
3734 saveptr = ptr;
3735 s = string_cat(s, &size, &ptr, US" ", 1);
3736 s = string_cat(s, &size, &ptr, au->public_name,
3737 Ustrlen(au->public_name));
3738 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3739 au->advertised = TRUE;
3740 }
3741 else
3742 au->advertised = FALSE;
3743
3744 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3745 }
3746
3747 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3748 if it has been included in the binary, and the host matches
3749 tls_advertise_hosts. We must *not* advertise if we are already in a
3750 secure connection. */
3751
3752 #ifdef SUPPORT_TLS
3753 if (tls_in.active < 0 &&
3754 verify_check_host(&tls_advertise_hosts) != FAIL)
3755 {
3756 s = string_cat(s, &size, &ptr, smtp_code, 3);
3757 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3758 tls_advertised = TRUE;
3759 }
3760 #endif
3761
3762 #ifndef DISABLE_PRDR
3763 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3764 if (prdr_enable)
3765 {
3766 s = string_cat(s, &size, &ptr, smtp_code, 3);
3767 s = string_cat(s, &size, &ptr, US"-PRDR\r\n", 7);
3768 }
3769 #endif
3770
3771 #ifdef EXPERIMENTAL_INTERNATIONAL
3772 if ( accept_8bitmime
3773 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
3774 {
3775 s = string_cat(s, &size, &ptr, smtp_code, 3);
3776 s = string_cat(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
3777 smtputf8_advertised = TRUE;
3778 }
3779 #endif
3780
3781 /* Finish off the multiline reply with one that is always available. */
3782
3783 s = string_cat(s, &size, &ptr, smtp_code, 3);
3784 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3785 }
3786
3787 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3788 has been seen. */
3789
3790 s[ptr] = 0;
3791
3792 #ifdef SUPPORT_TLS
3793 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
3794 #endif
3795
3796 {
3797 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
3798 }
3799 DEBUG(D_receive)
3800 {
3801 uschar *cr;
3802 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3803 memmove(cr, cr + 1, (ptr--) - (cr - s));
3804 debug_printf("SMTP>> %s", s);
3805 }
3806 helo_seen = TRUE;
3807
3808 /* Reset the protocol and the state, abandoning any previous message. */
3809 received_protocol =
3810 (sender_host_address ? protocols : protocols_local)
3811 [ (esmtp
3812 ? pextend + (sender_host_authenticated ? pauthed : 0)
3813 : pnormal)
3814 + (tls_in.active >= 0 ? pcrpted : 0)
3815 ];
3816 smtp_reset(reset_point);
3817 toomany = FALSE;
3818 break; /* HELO/EHLO */
3819
3820
3821 /* The MAIL command requires an address as an operand. All we do
3822 here is to parse it for syntactic correctness. The form "<>" is
3823 a special case which converts into an empty string. The start/end
3824 pointers in the original are not used further for this address, as
3825 it is the canonical extracted address which is all that is kept. */
3826
3827 case MAIL_CMD:
3828 HAD(SCH_MAIL);
3829 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3830 was_rej_mail = TRUE; /* Reset if accepted */
3831 env_mail_type_t * mail_args; /* Sanity check & validate args */
3832
3833 if (helo_required && !helo_seen)
3834 {
3835 smtp_printf("503 HELO or EHLO required\r\n");
3836 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3837 "HELO/EHLO given", host_and_ident(FALSE));
3838 break;
3839 }
3840
3841 if (sender_address != NULL)
3842 {
3843 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3844 US"sender already given");
3845 break;
3846 }
3847
3848 if (smtp_cmd_data[0] == 0)
3849 {
3850 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3851 US"MAIL must have an address operand");
3852 break;
3853 }
3854
3855 /* Check to see if the limit for messages per connection would be
3856 exceeded by accepting further messages. */
3857
3858 if (smtp_accept_max_per_connection > 0 &&
3859 smtp_mailcmd_count > smtp_accept_max_per_connection)
3860 {
3861 smtp_printf("421 too many messages in this connection\r\n");
3862 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3863 "messages in one connection", host_and_ident(TRUE));
3864 break;
3865 }
3866
3867 /* Reset for start of message - even if this is going to fail, we
3868 obviously need to throw away any previous data. */
3869
3870 smtp_reset(reset_point);
3871 toomany = FALSE;
3872 sender_data = recipient_data = NULL;
3873
3874 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3875
3876 if (esmtp) for(;;)
3877 {
3878 uschar *name, *value, *end;
3879 unsigned long int size;
3880 BOOL arg_error = FALSE;
3881
3882 if (!extract_option(&name, &value)) break;
3883
3884 for (mail_args = env_mail_type_list;
3885 (char *)mail_args < (char *)env_mail_type_list + sizeof(env_mail_type_list);
3886 mail_args++
3887 )
3888 if (strcmpic(name, mail_args->name) == 0)
3889 break;
3890 if (mail_args->need_value && strcmpic(value, US"") == 0)
3891 break;
3892
3893 switch(mail_args->value)
3894 {
3895 /* Handle SIZE= by reading the value. We don't do the check till later,
3896 in order to be able to log the sender address on failure. */
3897 case ENV_MAIL_OPT_SIZE:
3898 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
3899 {
3900 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3901 size = INT_MAX;
3902 message_size = (int)size;
3903 }
3904 else
3905 arg_error = TRUE;
3906 break;
3907
3908 /* If this session was initiated with EHLO and accept_8bitmime is set,
3909 Exim will have indicated that it supports the BODY=8BITMIME option. In
3910 fact, it does not support this according to the RFCs, in that it does not
3911 take any special action for forwarding messages containing 8-bit
3912 characters. That is why accept_8bitmime is not the default setting, but
3913 some sites want the action that is provided. We recognize both "8BITMIME"
3914 and "7BIT" as body types, but take no action. */
3915 case ENV_MAIL_OPT_BODY:
3916 if (accept_8bitmime) {
3917 if (strcmpic(value, US"8BITMIME") == 0)
3918 body_8bitmime = 8;
3919 else if (strcmpic(value, US"7BIT") == 0)
3920 body_8bitmime = 7;
3921 else
3922 {
3923 body_8bitmime = 0;
3924 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3925 US"invalid data for BODY");
3926 goto COMMAND_LOOP;
3927 }
3928 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
3929 break;
3930 }
3931 arg_error = TRUE;
3932 break;
3933
3934 /* Handle the two DSN options, but only if configured to do so (which
3935 will have caused "DSN" to be given in the EHLO response). The code itself
3936 is included only if configured in at build time. */
3937
3938 case ENV_MAIL_OPT_RET:
3939 if (dsn_advertised)
3940 {
3941 /* Check if RET has already been set */
3942 if (dsn_ret > 0)
3943 {
3944 synprot_error(L_smtp_syntax_error, 501, NULL,
3945 US"RET can be specified once only");
3946 goto COMMAND_LOOP;
3947 }
3948 dsn_ret = strcmpic(value, US"HDRS") == 0
3949 ? dsn_ret_hdrs
3950 : strcmpic(value, US"FULL") == 0
3951 ? dsn_ret_full
3952 : 0;
3953 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
3954 /* Check for invalid invalid value, and exit with error */
3955 if (dsn_ret == 0)
3956 {
3957 synprot_error(L_smtp_syntax_error, 501, NULL,
3958 US"Value for RET is invalid");
3959 goto COMMAND_LOOP;
3960 }
3961 }
3962 break;
3963 case ENV_MAIL_OPT_ENVID:
3964 if (dsn_advertised)
3965 {
3966 /* Check if the dsn envid has been already set */
3967 if (dsn_envid != NULL)
3968 {
3969 synprot_error(L_smtp_syntax_error, 501, NULL,
3970 US"ENVID can be specified once only");
3971 goto COMMAND_LOOP;
3972 }
3973 dsn_envid = string_copy(value);
3974 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
3975 }
3976 break;
3977
3978 /* Handle the AUTH extension. If the value given is not "<>" and either
3979 the ACL says "yes" or there is no ACL but the sending host is
3980 authenticated, we set it up as the authenticated sender. However, if the
3981 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3982 the condition is met. The value of AUTH is an xtext, which means that +,
3983 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3984 coding. */
3985 case ENV_MAIL_OPT_AUTH:
3986 if (Ustrcmp(value, "<>") != 0)
3987 {
3988 int rc;
3989 uschar *ignore_msg;
3990
3991 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3992 {
3993 /* Put back terminator overrides for error message */
3994 value[-1] = '=';
3995 name[-1] = ' ';
3996 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3997 US"invalid data for AUTH");
3998 goto COMMAND_LOOP;
3999 }
4000 if (acl_smtp_mailauth == NULL)
4001 {
4002 ignore_msg = US"client not authenticated";
4003 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4004 }
4005 else
4006 {
4007 ignore_msg = US"rejected by ACL";
4008 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4009 &user_msg, &log_msg);
4010 }
4011
4012 switch (rc)
4013 {
4014 case OK:
4015 if (authenticated_by == NULL ||
4016 authenticated_by->mail_auth_condition == NULL ||
4017 expand_check_condition(authenticated_by->mail_auth_condition,
4018 authenticated_by->name, US"authenticator"))
4019 break; /* Accept the AUTH */
4020
4021 ignore_msg = US"server_mail_auth_condition failed";
4022 if (authenticated_id != NULL)
4023 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4024 ignore_msg, authenticated_id);
4025
4026 /* Fall through */
4027
4028 case FAIL:
4029 authenticated_sender = NULL;
4030 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4031 value, host_and_ident(TRUE), ignore_msg);
4032 break;
4033
4034 /* Should only get DEFER or ERROR here. Put back terminator
4035 overrides for error message */
4036
4037 default:
4038 value[-1] = '=';
4039 name[-1] = ' ';
4040 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4041 log_msg);
4042 goto COMMAND_LOOP;
4043 }
4044 }
4045 break;
4046
4047 #ifndef DISABLE_PRDR
4048 case ENV_MAIL_OPT_PRDR:
4049 if (prdr_enable)
4050 prdr_requested = TRUE;
4051 break;
4052 #endif
4053
4054 #ifdef EXPERIMENTAL_INTERNATIONAL
4055 case ENV_MAIL_OPT_UTF8:
4056 if (smtputf8_advertised)
4057 {
4058 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4059 message_smtputf8 = allow_utf8_domains = TRUE;
4060 received_protocol = string_sprintf("utf8%s", received_protocol);
4061 }
4062 break;
4063 #endif
4064 /* Unknown option. Stick back the terminator characters and break
4065 the loop. Do the name-terminator second as extract_option sets
4066 value==name when it found no equal-sign.
4067 An error for a malformed address will occur. */
4068 default:
4069 value[-1] = '=';
4070 name[-1] = ' ';
4071 arg_error = TRUE;
4072 break;
4073 }
4074 /* Break out of for loop if switch() had bad argument or
4075 when start of the email address is reached */