8086e94563b9f0a75dd0ea9559ecaada20fe779b
[exim.git] / src / src / smtp_in.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2014 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8 /* Functions for handling an incoming SMTP call. */
9
10
11 #include "exim.h"
12
13
14 /* Initialize for TCP wrappers if so configured. It appears that the macro
15 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
16 including that header, and restore its value afterwards. */
17
18 #ifdef USE_TCP_WRAPPERS
19
20 #if HAVE_IPV6
21 #define EXIM_HAVE_IPV6
22 #endif
23 #undef HAVE_IPV6
24 #include <tcpd.h>
25 #undef HAVE_IPV6
26 #ifdef EXIM_HAVE_IPV6
27 #define HAVE_IPV6 TRUE
28 #endif
29
30 int allow_severity = LOG_INFO;
31 int deny_severity = LOG_NOTICE;
32 uschar *tcp_wrappers_name;
33 #endif
34
35
36 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
37 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
38 commands that accept arguments, and this in particular applies to AUTH, where
39 the data can be quite long. More recently this value was 2048 in Exim;
40 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
41 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
42 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
43 we need room to handle large base64-encoded AUTHs for GSSAPI.
44 */
45
46 #define smtp_cmd_buffer_size 16384
47
48 /* Size of buffer for reading SMTP incoming packets */
49
50 #define in_buffer_size 8192
51
52 /* Structure for SMTP command list */
53
54 typedef struct {
55 const char *name;
56 int len;
57 short int cmd;
58 short int has_arg;
59 short int is_mail_cmd;
60 } smtp_cmd_list;
61
62 /* Codes for identifying commands. We order them so that those that come first
63 are those for which synchronization is always required. Checking this can help
64 block some spam. */
65
66 enum {
67 /* These commands are required to be synchronized, i.e. to be the last in a
68 block of commands when pipelining. */
69
70 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
71 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
72 ETRN_CMD, /* This by analogy with TURN from the RFC */
73 STARTTLS_CMD, /* Required by the STARTTLS RFC */
74
75 /* This is a dummy to identify the non-sync commands when pipelining */
76
77 NON_SYNC_CMD_PIPELINING,
78
79 /* These commands need not be synchronized when pipelining */
80
81 MAIL_CMD, RCPT_CMD, RSET_CMD,
82
83 /* This is a dummy to identify the non-sync commands when not pipelining */
84
85 NON_SYNC_CMD_NON_PIPELINING,
86
87 /* I have been unable to find a statement about the use of pipelining
88 with AUTH, so to be on the safe side it is here, though I kind of feel
89 it should be up there with the synchronized commands. */
90
91 AUTH_CMD,
92
93 /* I'm not sure about these, but I don't think they matter. */
94
95 QUIT_CMD, HELP_CMD,
96
97 #ifdef EXPERIMENTAL_PROXY
98 PROXY_FAIL_IGNORE_CMD,
99 #endif
100
101 /* These are specials that don't correspond to actual commands */
102
103 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
104 TOO_MANY_NONMAIL_CMD };
105
106
107 /* This is a convenience macro for adding the identity of an SMTP command
108 to the circular buffer that holds a list of the last n received. */
109
110 #define HAD(n) \
111 smtp_connection_had[smtp_ch_index++] = n; \
112 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
113
114
115 /*************************************************
116 * Local static variables *
117 *************************************************/
118
119 static auth_instance *authenticated_by;
120 static BOOL auth_advertised;
121 #ifdef SUPPORT_TLS
122 static BOOL tls_advertised;
123 #endif
124 static BOOL dsn_advertised;
125 static BOOL esmtp;
126 static BOOL helo_required = FALSE;
127 static BOOL helo_verify = FALSE;
128 static BOOL helo_seen;
129 static BOOL helo_accept_junk;
130 static BOOL count_nonmail;
131 static BOOL pipelining_advertised;
132 static BOOL rcpt_smtp_response_same;
133 static BOOL rcpt_in_progress;
134 static int nonmail_command_count;
135 static BOOL smtp_exit_function_called = 0;
136 #ifdef EXPERIMENTAL_INTERNATIONAL
137 static BOOL smtputf8_advertised;
138 #endif
139 static int synprot_error_count;
140 static int unknown_command_count;
141 static int sync_cmd_limit;
142 static int smtp_write_error = 0;
143
144 static uschar *rcpt_smtp_response;
145 static uschar *smtp_data_buffer;
146 static uschar *smtp_cmd_data;
147
148 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
149 final fields of all except AUTH are forced TRUE at the start of a new message
150 setup, to allow one of each between messages that is not counted as a nonmail
151 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
152 allow a new EHLO after starting up TLS.
153
154 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
155 counted. However, the flag is changed when AUTH is received, so that multiple
156 failing AUTHs will eventually hit the limit. After a successful AUTH, another
157 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
158 forced TRUE, to allow for the re-authentication that can happen at that point.
159
160 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
161 count of non-mail commands and possibly provoke an error. */
162
163 static smtp_cmd_list cmd_list[] = {
164 /* name len cmd has_arg is_mail_cmd */
165
166 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
167 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
168 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
169 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
170 #ifdef SUPPORT_TLS
171 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
172 #endif
173
174 /* If you change anything above here, also fix the definitions below. */
175
176 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
177 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
178 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
179 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
180 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
181 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
182 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
183 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
184 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
185 };
186
187 static smtp_cmd_list *cmd_list_end =
188 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
189
190 #define CMD_LIST_RSET 0
191 #define CMD_LIST_HELO 1
192 #define CMD_LIST_EHLO 2
193 #define CMD_LIST_AUTH 3
194 #define CMD_LIST_STARTTLS 4
195
196 /* This list of names is used for performing the smtp_no_mail logging action.
197 It must be kept in step with the SCH_xxx enumerations. */
198
199 static uschar *smtp_names[] =
200 {
201 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
202 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
203 US"VRFY" };
204
205 static uschar *protocols[] = {
206 US"local-smtp", /* HELO */
207 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
208 US"local-esmtp", /* EHLO */
209 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
210 US"local-esmtpa", /* EHLO->AUTH */
211 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
212 };
213
214 #define pnormal 0
215 #define pextend 2
216 #define pcrpted 1 /* added to pextend or pnormal */
217 #define pauthed 2 /* added to pextend */
218 #define pnlocal 6 /* offset to remove "local" */
219
220 /* Sanity check and validate optional args to MAIL FROM: envelope */
221 enum {
222 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
223 #ifndef DISABLE_PRDR
224 ENV_MAIL_OPT_PRDR,
225 #endif
226 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
227 #ifdef EXPERIMENTAL_INTERNATIONAL
228 ENV_MAIL_OPT_UTF8,
229 #endif
230 ENV_MAIL_OPT_NULL
231 };
232 typedef struct {
233 uschar * name; /* option requested during MAIL cmd */
234 int value; /* enum type */
235 BOOL need_value; /* TRUE requires value (name=value pair format)
236 FALSE is a singleton */
237 } env_mail_type_t;
238 static env_mail_type_t env_mail_type_list[] = {
239 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
240 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
241 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
242 #ifndef DISABLE_PRDR
243 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
244 #endif
245 { US"RET", ENV_MAIL_OPT_RET, TRUE },
246 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
247 #ifdef EXPERIMENTAL_INTERNATIONAL
248 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
249 #endif
250 { US"NULL", ENV_MAIL_OPT_NULL, FALSE }
251 };
252
253 /* When reading SMTP from a remote host, we have to use our own versions of the
254 C input-reading functions, in order to be able to flush the SMTP output only
255 when about to read more data from the socket. This is the only way to get
256 optimal performance when the client is using pipelining. Flushing for every
257 command causes a separate packet and reply packet each time; saving all the
258 responses up (when pipelining) combines them into one packet and one response.
259
260 For simplicity, these functions are used for *all* SMTP input, not only when
261 receiving over a socket. However, after setting up a secure socket (SSL), input
262 is read via the OpenSSL library, and another set of functions is used instead
263 (see tls.c).
264
265 These functions are set in the receive_getc etc. variables and called with the
266 same interface as the C functions. However, since there can only ever be
267 one incoming SMTP call, we just use a single buffer and flags. There is no need
268 to implement a complicated private FILE-like structure.*/
269
270 static uschar *smtp_inbuffer;
271 static uschar *smtp_inptr;
272 static uschar *smtp_inend;
273 static int smtp_had_eof;
274 static int smtp_had_error;
275
276
277 /*************************************************
278 * SMTP version of getc() *
279 *************************************************/
280
281 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
282 it flushes the output, and refills the buffer, with a timeout. The signal
283 handler is set appropriately by the calling function. This function is not used
284 after a connection has negotated itself into an TLS/SSL state.
285
286 Arguments: none
287 Returns: the next character or EOF
288 */
289
290 int
291 smtp_getc(void)
292 {
293 if (smtp_inptr >= smtp_inend)
294 {
295 int rc, save_errno;
296 fflush(smtp_out);
297 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
298 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
299 save_errno = errno;
300 alarm(0);
301 if (rc <= 0)
302 {
303 /* Must put the error text in fixed store, because this might be during
304 header reading, where it releases unused store above the header. */
305 if (rc < 0)
306 {
307 smtp_had_error = save_errno;
308 smtp_read_error = string_copy_malloc(
309 string_sprintf(" (error: %s)", strerror(save_errno)));
310 }
311 else smtp_had_eof = 1;
312 return EOF;
313 }
314 #ifndef DISABLE_DKIM
315 dkim_exim_verify_feed(smtp_inbuffer, rc);
316 #endif
317 smtp_inend = smtp_inbuffer + rc;
318 smtp_inptr = smtp_inbuffer;
319 }
320 return *smtp_inptr++;
321 }
322
323
324
325 /*************************************************
326 * SMTP version of ungetc() *
327 *************************************************/
328
329 /* Puts a character back in the input buffer. Only ever
330 called once.
331
332 Arguments:
333 ch the character
334
335 Returns: the character
336 */
337
338 int
339 smtp_ungetc(int ch)
340 {
341 *(--smtp_inptr) = ch;
342 return ch;
343 }
344
345
346
347
348 /*************************************************
349 * SMTP version of feof() *
350 *************************************************/
351
352 /* Tests for a previous EOF
353
354 Arguments: none
355 Returns: non-zero if the eof flag is set
356 */
357
358 int
359 smtp_feof(void)
360 {
361 return smtp_had_eof;
362 }
363
364
365
366
367 /*************************************************
368 * SMTP version of ferror() *
369 *************************************************/
370
371 /* Tests for a previous read error, and returns with errno
372 restored to what it was when the error was detected.
373
374 Arguments: none
375 Returns: non-zero if the error flag is set
376 */
377
378 int
379 smtp_ferror(void)
380 {
381 errno = smtp_had_error;
382 return smtp_had_error;
383 }
384
385
386
387 /*************************************************
388 * Test for characters in the SMTP buffer *
389 *************************************************/
390
391 /* Used at the end of a message
392
393 Arguments: none
394 Returns: TRUE/FALSE
395 */
396
397 BOOL
398 smtp_buffered(void)
399 {
400 return smtp_inptr < smtp_inend;
401 }
402
403
404
405 /*************************************************
406 * Write formatted string to SMTP channel *
407 *************************************************/
408
409 /* This is a separate function so that we don't have to repeat everything for
410 TLS support or debugging. It is global so that the daemon and the
411 authentication functions can use it. It does not return any error indication,
412 because major problems such as dropped connections won't show up till an output
413 flush for non-TLS connections. The smtp_fflush() function is available for
414 checking that: for convenience, TLS output errors are remembered here so that
415 they are also picked up later by smtp_fflush().
416
417 Arguments:
418 format format string
419 ... optional arguments
420
421 Returns: nothing
422 */
423
424 void
425 smtp_printf(const char *format, ...)
426 {
427 va_list ap;
428
429 va_start(ap, format);
430 smtp_vprintf(format, ap);
431 va_end(ap);
432 }
433
434 /* This is split off so that verify.c:respond_printf() can, in effect, call
435 smtp_printf(), bearing in mind that in C a vararg function can't directly
436 call another vararg function, only a function which accepts a va_list. */
437
438 void
439 smtp_vprintf(const char *format, va_list ap)
440 {
441 BOOL yield;
442
443 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
444
445 DEBUG(D_receive)
446 {
447 void *reset_point = store_get(0);
448 uschar *msg_copy, *cr, *end;
449 msg_copy = string_copy(big_buffer);
450 end = msg_copy + Ustrlen(msg_copy);
451 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
452 memmove(cr, cr + 1, (end--) - cr);
453 debug_printf("SMTP>> %s", msg_copy);
454 store_reset(reset_point);
455 }
456
457 if (!yield)
458 {
459 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
460 smtp_closedown(US"Unexpected error");
461 exim_exit(EXIT_FAILURE);
462 }
463
464 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
465 have had the same. Note: this code is also present in smtp_respond(). It would
466 be tidier to have it only in one place, but when it was added, it was easier to
467 do it that way, so as not to have to mess with the code for the RCPT command,
468 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
469
470 if (rcpt_in_progress)
471 {
472 if (rcpt_smtp_response == NULL)
473 rcpt_smtp_response = string_copy(big_buffer);
474 else if (rcpt_smtp_response_same &&
475 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
476 rcpt_smtp_response_same = FALSE;
477 rcpt_in_progress = FALSE;
478 }
479
480 /* Now write the string */
481
482 #ifdef SUPPORT_TLS
483 if (tls_in.active >= 0)
484 {
485 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
486 smtp_write_error = -1;
487 }
488 else
489 #endif
490
491 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
492 }
493
494
495
496 /*************************************************
497 * Flush SMTP out and check for error *
498 *************************************************/
499
500 /* This function isn't currently used within Exim (it detects errors when it
501 tries to read the next SMTP input), but is available for use in local_scan().
502 For non-TLS connections, it flushes the output and checks for errors. For
503 TLS-connections, it checks for a previously-detected TLS write error.
504
505 Arguments: none
506 Returns: 0 for no error; -1 after an error
507 */
508
509 int
510 smtp_fflush(void)
511 {
512 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
513 return smtp_write_error;
514 }
515
516
517
518 /*************************************************
519 * SMTP command read timeout *
520 *************************************************/
521
522 /* Signal handler for timing out incoming SMTP commands. This attempts to
523 finish off tidily.
524
525 Argument: signal number (SIGALRM)
526 Returns: nothing
527 */
528
529 static void
530 command_timeout_handler(int sig)
531 {
532 sig = sig; /* Keep picky compilers happy */
533 log_write(L_lost_incoming_connection,
534 LOG_MAIN, "SMTP command timeout on%s connection from %s",
535 (tls_in.active >= 0)? " TLS" : "",
536 host_and_ident(FALSE));
537 if (smtp_batched_input)
538 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
539 smtp_notquit_exit(US"command-timeout", US"421",
540 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
541 exim_exit(EXIT_FAILURE);
542 }
543
544
545
546 /*************************************************
547 * SIGTERM received *
548 *************************************************/
549
550 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
551
552 Argument: signal number (SIGTERM)
553 Returns: nothing
554 */
555
556 static void
557 command_sigterm_handler(int sig)
558 {
559 sig = sig; /* Keep picky compilers happy */
560 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
561 if (smtp_batched_input)
562 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
563 smtp_notquit_exit(US"signal-exit", US"421",
564 US"%s: Service not available - closing connection", smtp_active_hostname);
565 exim_exit(EXIT_FAILURE);
566 }
567
568
569
570
571 #ifdef EXPERIMENTAL_PROXY
572 /*************************************************
573 * Restore socket timeout to previous value *
574 *************************************************/
575 /* If the previous value was successfully retrieved, restore
576 it before returning control to the non-proxy routines
577
578 Arguments: fd - File descriptor for input
579 get_ok - Successfully retrieved previous values
580 tvtmp - Time struct with previous values
581 vslen - Length of time struct
582 Returns: none
583 */
584 static void
585 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
586 {
587 if (get_ok == 0)
588 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
589 }
590
591 /*************************************************
592 * Check if host is required proxy host *
593 *************************************************/
594 /* The function determines if inbound host will be a regular smtp host
595 or if it is configured that it must use Proxy Protocol.
596
597 Arguments: none
598 Returns: bool
599 */
600
601 static BOOL
602 check_proxy_protocol_host()
603 {
604 int rc;
605 /* Cannot configure local connection as a proxy inbound */
606 if (sender_host_address == NULL) return proxy_session;
607
608 rc = verify_check_this_host(&proxy_required_hosts, NULL, NULL,
609 sender_host_address, NULL);
610 if (rc == OK)
611 {
612 DEBUG(D_receive)
613 debug_printf("Detected proxy protocol configured host\n");
614 proxy_session = TRUE;
615 }
616 return proxy_session;
617 }
618
619
620 /*************************************************
621 * Setup host for proxy protocol *
622 *************************************************/
623 /* The function configures the connection based on a header from the
624 inbound host to use Proxy Protocol. The specification is very exact
625 so exit with an error if do not find the exact required pieces. This
626 includes an incorrect number of spaces separating args.
627
628 Arguments: none
629 Returns: int
630 */
631
632 static BOOL
633 setup_proxy_protocol_host()
634 {
635 union {
636 struct {
637 uschar line[108];
638 } v1;
639 struct {
640 uschar sig[12];
641 uint8_t ver_cmd;
642 uint8_t fam;
643 uint16_t len;
644 union {
645 struct { /* TCP/UDP over IPv4, len = 12 */
646 uint32_t src_addr;
647 uint32_t dst_addr;
648 uint16_t src_port;
649 uint16_t dst_port;
650 } ip4;
651 struct { /* TCP/UDP over IPv6, len = 36 */
652 uint8_t src_addr[16];
653 uint8_t dst_addr[16];
654 uint16_t src_port;
655 uint16_t dst_port;
656 } ip6;
657 struct { /* AF_UNIX sockets, len = 216 */
658 uschar src_addr[108];
659 uschar dst_addr[108];
660 } unx;
661 } addr;
662 } v2;
663 } hdr;
664
665 /* Temp variables used in PPv2 address:port parsing */
666 uint16_t tmpport;
667 char tmpip[INET_ADDRSTRLEN];
668 struct sockaddr_in tmpaddr;
669 char tmpip6[INET6_ADDRSTRLEN];
670 struct sockaddr_in6 tmpaddr6;
671
672 int get_ok = 0;
673 int size, ret, fd;
674 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
675 uschar *iptype; /* To display debug info */
676 struct timeval tv;
677 socklen_t vslen = 0;
678 struct timeval tvtmp;
679
680 vslen = sizeof(struct timeval);
681
682 fd = fileno(smtp_in);
683
684 /* Save current socket timeout values */
685 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
686 &vslen);
687
688 /* Proxy Protocol host must send header within a short time
689 (default 3 seconds) or it's considered invalid */
690 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
691 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
692 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
693 sizeof(struct timeval));
694
695 do
696 {
697 /* The inbound host was declared to be a Proxy Protocol host, so
698 don't do a PEEK into the data, actually slurp it up. */
699 ret = recv(fd, &hdr, sizeof(hdr), 0);
700 }
701 while (ret == -1 && errno == EINTR);
702
703 if (ret == -1)
704 {
705 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
706 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
707 }
708
709 if (ret >= 16 &&
710 memcmp(&hdr.v2, v2sig, 12) == 0)
711 {
712 uint8_t ver, cmd;
713
714 /* May 2014: haproxy combined the version and command into one byte to
715 allow two full bytes for the length field in order to proxy SSL
716 connections. SSL Proxy is not supported in this version of Exim, but
717 must still seperate values here. */
718 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
719 cmd = (hdr.v2.ver_cmd & 0x0f);
720
721 if (ver != 0x02)
722 {
723 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
724 goto proxyfail;
725 }
726 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
727 /* The v2 header will always be 16 bytes per the spec. */
728 size = 16 + hdr.v2.len;
729 if (ret < size)
730 {
731 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
732 ret, size);
733 goto proxyfail;
734 }
735 switch (cmd)
736 {
737 case 0x01: /* PROXY command */
738 switch (hdr.v2.fam)
739 {
740 case 0x11: /* TCPv4 address type */
741 iptype = US"IPv4";
742 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
743 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
744 if (!string_is_ip_address(US tmpip,NULL))
745 {
746 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
747 return ERRNO_PROXYFAIL;
748 }
749 proxy_host_address = sender_host_address;
750 sender_host_address = string_copy(US tmpip);
751 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
752 proxy_host_port = sender_host_port;
753 sender_host_port = tmpport;
754 /* Save dest ip/port */
755 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
756 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
757 if (!string_is_ip_address(US tmpip,NULL))
758 {
759 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
760 return ERRNO_PROXYFAIL;
761 }
762 proxy_target_address = string_copy(US tmpip);
763 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
764 proxy_target_port = tmpport;
765 goto done;
766 case 0x21: /* TCPv6 address type */
767 iptype = US"IPv6";
768 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
769 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
770 if (!string_is_ip_address(US tmpip6,NULL))
771 {
772 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
773 return ERRNO_PROXYFAIL;
774 }
775 proxy_host_address = sender_host_address;
776 sender_host_address = string_copy(US tmpip6);
777 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
778 proxy_host_port = sender_host_port;
779 sender_host_port = tmpport;
780 /* Save dest ip/port */
781 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
782 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
783 if (!string_is_ip_address(US tmpip6,NULL))
784 {
785 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
786 return ERRNO_PROXYFAIL;
787 }
788 proxy_target_address = string_copy(US tmpip6);
789 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
790 proxy_target_port = tmpport;
791 goto done;
792 default:
793 DEBUG(D_receive)
794 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
795 hdr.v2.fam);
796 goto proxyfail;
797 }
798 /* Unsupported protocol, keep local connection address */
799 break;
800 case 0x00: /* LOCAL command */
801 /* Keep local connection address for LOCAL */
802 break;
803 default:
804 DEBUG(D_receive)
805 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
806 goto proxyfail;
807 }
808 }
809 else if (ret >= 8 &&
810 memcmp(hdr.v1.line, "PROXY", 5) == 0)
811 {
812 uschar *p = string_copy(hdr.v1.line);
813 uschar *end = memchr(p, '\r', ret - 1);
814 uschar *sp; /* Utility variables follow */
815 int tmp_port;
816 char *endc;
817
818 if (!end || end[1] != '\n')
819 {
820 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
821 goto proxyfail;
822 }
823 *end = '\0'; /* Terminate the string */
824 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
825 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
826 /* Step through the string looking for the required fields. Ensure
827 strict adherance to required formatting, exit for any error. */
828 p += 5;
829 if (!isspace(*(p++)))
830 {
831 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
832 goto proxyfail;
833 }
834 if (!Ustrncmp(p, CCS"TCP4", 4))
835 iptype = US"IPv4";
836 else if (!Ustrncmp(p,CCS"TCP6", 4))
837 iptype = US"IPv6";
838 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
839 {
840 iptype = US"Unknown";
841 goto done;
842 }
843 else
844 {
845 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
846 goto proxyfail;
847 }
848
849 p += Ustrlen(iptype);
850 if (!isspace(*(p++)))
851 {
852 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
853 goto proxyfail;
854 }
855 /* Find the end of the arg */
856 if ((sp = Ustrchr(p, ' ')) == NULL)
857 {
858 DEBUG(D_receive)
859 debug_printf("Did not find proxied src %s\n", iptype);
860 goto proxyfail;
861 }
862 *sp = '\0';
863 if(!string_is_ip_address(p,NULL))
864 {
865 DEBUG(D_receive)
866 debug_printf("Proxied src arg is not an %s address\n", iptype);
867 goto proxyfail;
868 }
869 proxy_host_address = sender_host_address;
870 sender_host_address = p;
871 p = sp + 1;
872 if ((sp = Ustrchr(p, ' ')) == NULL)
873 {
874 DEBUG(D_receive)
875 debug_printf("Did not find proxy dest %s\n", iptype);
876 goto proxyfail;
877 }
878 *sp = '\0';
879 if(!string_is_ip_address(p,NULL))
880 {
881 DEBUG(D_receive)
882 debug_printf("Proxy dest arg is not an %s address\n", iptype);
883 goto proxyfail;
884 }
885 proxy_target_address = p;
886 p = sp + 1;
887 if ((sp = Ustrchr(p, ' ')) == NULL)
888 {
889 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
890 goto proxyfail;
891 }
892 *sp = '\0';
893 tmp_port = strtol(CCS p,&endc,10);
894 if (*endc || tmp_port == 0)
895 {
896 DEBUG(D_receive)
897 debug_printf("Proxied src port '%s' not an integer\n", p);
898 goto proxyfail;
899 }
900 proxy_host_port = sender_host_port;
901 sender_host_port = tmp_port;
902 p = sp + 1;
903 if ((sp = Ustrchr(p, '\0')) == NULL)
904 {
905 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
906 goto proxyfail;
907 }
908 tmp_port = strtol(CCS p,&endc,10);
909 if (*endc || tmp_port == 0)
910 {
911 DEBUG(D_receive)
912 debug_printf("Proxy dest port '%s' not an integer\n", p);
913 goto proxyfail;
914 }
915 proxy_target_port = tmp_port;
916 /* Already checked for /r /n above. Good V1 header received. */
917 goto done;
918 }
919 else
920 {
921 /* Wrong protocol */
922 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
923 goto proxyfail;
924 }
925
926 proxyfail:
927 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
928 /* Don't flush any potential buffer contents. Any input should cause a
929 synchronization failure */
930 return FALSE;
931
932 done:
933 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
934 DEBUG(D_receive)
935 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
936 return proxy_session;
937 }
938 #endif
939
940 /*************************************************
941 * Read one command line *
942 *************************************************/
943
944 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
945 There are sites that don't do this, and in any case internal SMTP probably
946 should check only for LF. Consequently, we check here for LF only. The line
947 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
948 an unknown command. The command is read into the global smtp_cmd_buffer so that
949 it is available via $smtp_command.
950
951 The character reading routine sets up a timeout for each block actually read
952 from the input (which may contain more than one command). We set up a special
953 signal handler that closes down the session on a timeout. Control does not
954 return when it runs.
955
956 Arguments:
957 check_sync if TRUE, check synchronization rules if global option is TRUE
958
959 Returns: a code identifying the command (enumerated above)
960 */
961
962 static int
963 smtp_read_command(BOOL check_sync)
964 {
965 int c;
966 int ptr = 0;
967 smtp_cmd_list *p;
968 BOOL hadnull = FALSE;
969
970 os_non_restarting_signal(SIGALRM, command_timeout_handler);
971
972 while ((c = (receive_getc)()) != '\n' && c != EOF)
973 {
974 if (ptr >= smtp_cmd_buffer_size)
975 {
976 os_non_restarting_signal(SIGALRM, sigalrm_handler);
977 return OTHER_CMD;
978 }
979 if (c == 0)
980 {
981 hadnull = TRUE;
982 c = '?';
983 }
984 smtp_cmd_buffer[ptr++] = c;
985 }
986
987 receive_linecount++; /* For BSMTP errors */
988 os_non_restarting_signal(SIGALRM, sigalrm_handler);
989
990 /* If hit end of file, return pseudo EOF command. Whether we have a
991 part-line already read doesn't matter, since this is an error state. */
992
993 if (c == EOF) return EOF_CMD;
994
995 /* Remove any CR and white space at the end of the line, and terminate the
996 string. */
997
998 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
999 smtp_cmd_buffer[ptr] = 0;
1000
1001 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1002
1003 /* NULLs are not allowed in SMTP commands */
1004
1005 if (hadnull) return BADCHAR_CMD;
1006
1007 /* Scan command list and return identity, having set the data pointer
1008 to the start of the actual data characters. Check for SMTP synchronization
1009 if required. */
1010
1011 for (p = cmd_list; p < cmd_list_end; p++)
1012 {
1013 #ifdef EXPERIMENTAL_PROXY
1014 /* Only allow QUIT command if Proxy Protocol parsing failed */
1015 if (proxy_session && proxy_session_failed)
1016 {
1017 if (p->cmd != QUIT_CMD)
1018 continue;
1019 }
1020 #endif
1021 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
1022 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
1023 smtp_cmd_buffer[p->len] == 0 ||
1024 smtp_cmd_buffer[p->len] == ' '))
1025 {
1026 if (smtp_inptr < smtp_inend && /* Outstanding input */
1027 p->cmd < sync_cmd_limit && /* Command should sync */
1028 check_sync && /* Local flag set */
1029 smtp_enforce_sync && /* Global flag set */
1030 sender_host_address != NULL && /* Not local input */
1031 !sender_host_notsocket) /* Really is a socket */
1032 return BADSYN_CMD;
1033
1034 /* The variables $smtp_command and $smtp_command_argument point into the
1035 unmodified input buffer. A copy of the latter is taken for actual
1036 processing, so that it can be chopped up into separate parts if necessary,
1037 for example, when processing a MAIL command options such as SIZE that can
1038 follow the sender address. */
1039
1040 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1041 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1042 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1043 smtp_cmd_data = smtp_data_buffer;
1044
1045 /* Count non-mail commands from those hosts that are controlled in this
1046 way. The default is all hosts. We don't waste effort checking the list
1047 until we get a non-mail command, but then cache the result to save checking
1048 again. If there's a DEFER while checking the host, assume it's in the list.
1049
1050 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1051 start of each incoming message by fiddling with the value in the table. */
1052
1053 if (!p->is_mail_cmd)
1054 {
1055 if (count_nonmail == TRUE_UNSET) count_nonmail =
1056 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1057 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1058 return TOO_MANY_NONMAIL_CMD;
1059 }
1060
1061 /* If there is data for a command that does not expect it, generate the
1062 error here. */
1063
1064 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1065 }
1066 }
1067
1068 #ifdef EXPERIMENTAL_PROXY
1069 /* Only allow QUIT command if Proxy Protocol parsing failed */
1070 if (proxy_session && proxy_session_failed)
1071 return PROXY_FAIL_IGNORE_CMD;
1072 #endif
1073
1074 /* Enforce synchronization for unknown commands */
1075
1076 if (smtp_inptr < smtp_inend && /* Outstanding input */
1077 check_sync && /* Local flag set */
1078 smtp_enforce_sync && /* Global flag set */
1079 sender_host_address != NULL && /* Not local input */
1080 !sender_host_notsocket) /* Really is a socket */
1081 return BADSYN_CMD;
1082
1083 return OTHER_CMD;
1084 }
1085
1086
1087
1088 /*************************************************
1089 * Recheck synchronization *
1090 *************************************************/
1091
1092 /* Synchronization checks can never be perfect because a packet may be on its
1093 way but not arrived when the check is done. Such checks can in any case only be
1094 done when TLS is not in use. Normally, the checks happen when commands are
1095 read: Exim ensures that there is no more input in the input buffer. In normal
1096 cases, the response to the command will be fast, and there is no further check.
1097
1098 However, for some commands an ACL is run, and that can include delays. In those
1099 cases, it is useful to do another check on the input just before sending the
1100 response. This also applies at the start of a connection. This function does
1101 that check by means of the select() function, as long as the facility is not
1102 disabled or inappropriate. A failure of select() is ignored.
1103
1104 When there is unwanted input, we read it so that it appears in the log of the
1105 error.
1106
1107 Arguments: none
1108 Returns: TRUE if all is well; FALSE if there is input pending
1109 */
1110
1111 static BOOL
1112 check_sync(void)
1113 {
1114 int fd, rc;
1115 fd_set fds;
1116 struct timeval tzero;
1117
1118 if (!smtp_enforce_sync || sender_host_address == NULL ||
1119 sender_host_notsocket || tls_in.active >= 0)
1120 return TRUE;
1121
1122 fd = fileno(smtp_in);
1123 FD_ZERO(&fds);
1124 FD_SET(fd, &fds);
1125 tzero.tv_sec = 0;
1126 tzero.tv_usec = 0;
1127 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1128
1129 if (rc <= 0) return TRUE; /* Not ready to read */
1130 rc = smtp_getc();
1131 if (rc < 0) return TRUE; /* End of file or error */
1132
1133 smtp_ungetc(rc);
1134 rc = smtp_inend - smtp_inptr;
1135 if (rc > 150) rc = 150;
1136 smtp_inptr[rc] = 0;
1137 return FALSE;
1138 }
1139
1140
1141
1142 /*************************************************
1143 * Forced closedown of call *
1144 *************************************************/
1145
1146 /* This function is called from log.c when Exim is dying because of a serious
1147 disaster, and also from some other places. If an incoming non-batched SMTP
1148 channel is open, it swallows the rest of the incoming message if in the DATA
1149 phase, sends the reply string, and gives an error to all subsequent commands
1150 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1151 smtp_in.
1152
1153 Arguments:
1154 message SMTP reply string to send, excluding the code
1155
1156 Returns: nothing
1157 */
1158
1159 void
1160 smtp_closedown(uschar *message)
1161 {
1162 if (smtp_in == NULL || smtp_batched_input) return;
1163 receive_swallow_smtp();
1164 smtp_printf("421 %s\r\n", message);
1165
1166 for (;;)
1167 {
1168 switch(smtp_read_command(FALSE))
1169 {
1170 case EOF_CMD:
1171 return;
1172
1173 case QUIT_CMD:
1174 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1175 mac_smtp_fflush();
1176 return;
1177
1178 case RSET_CMD:
1179 smtp_printf("250 Reset OK\r\n");
1180 break;
1181
1182 default:
1183 smtp_printf("421 %s\r\n", message);
1184 break;
1185 }
1186 }
1187 }
1188
1189
1190
1191
1192 /*************************************************
1193 * Set up connection info for logging *
1194 *************************************************/
1195
1196 /* This function is called when logging information about an SMTP connection.
1197 It sets up appropriate source information, depending on the type of connection.
1198 If sender_fullhost is NULL, we are at a very early stage of the connection;
1199 just use the IP address.
1200
1201 Argument: none
1202 Returns: a string describing the connection
1203 */
1204
1205 uschar *
1206 smtp_get_connection_info(void)
1207 {
1208 uschar *hostname = (sender_fullhost == NULL)?
1209 sender_host_address : sender_fullhost;
1210
1211 if (host_checking)
1212 return string_sprintf("SMTP connection from %s", hostname);
1213
1214 if (sender_host_unknown || sender_host_notsocket)
1215 return string_sprintf("SMTP connection from %s", sender_ident);
1216
1217 if (is_inetd)
1218 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1219
1220 if ((log_extra_selector & LX_incoming_interface) != 0 &&
1221 interface_address != NULL)
1222 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1223 interface_address, interface_port);
1224
1225 return string_sprintf("SMTP connection from %s", hostname);
1226 }
1227
1228
1229
1230 #ifdef SUPPORT_TLS
1231 /* Append TLS-related information to a log line
1232
1233 Arguments:
1234 s String under construction: allocated string to extend, or NULL
1235 sizep Pointer to current allocation size (update on return), or NULL
1236 ptrp Pointer to index for new entries in string (update on return), or NULL
1237
1238 Returns: Allocated string or NULL
1239 */
1240 static uschar *
1241 s_tlslog(uschar * s, int * sizep, int * ptrp)
1242 {
1243 int size = sizep ? *sizep : 0;
1244 int ptr = ptrp ? *ptrp : 0;
1245
1246 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_in.cipher != NULL)
1247 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1248 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
1249 tls_in.cipher != NULL)
1250 s = string_append(s, &size, &ptr, 2, US" CV=",
1251 tls_in.certificate_verified? "yes":"no");
1252 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_in.peerdn != NULL)
1253 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1254 string_printing(tls_in.peerdn), US"\"");
1255 if ((log_extra_selector & LX_tls_sni) != 0 && tls_in.sni != NULL)
1256 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1257 string_printing(tls_in.sni), US"\"");
1258
1259 if (s)
1260 {
1261 s[ptr] = '\0';
1262 if (sizep) *sizep = size;
1263 if (ptrp) *ptrp = ptr;
1264 }
1265 return s;
1266 }
1267 #endif
1268
1269 /*************************************************
1270 * Log lack of MAIL if so configured *
1271 *************************************************/
1272
1273 /* This function is called when an SMTP session ends. If the log selector
1274 smtp_no_mail is set, write a log line giving some details of what has happened
1275 in the SMTP session.
1276
1277 Arguments: none
1278 Returns: nothing
1279 */
1280
1281 void
1282 smtp_log_no_mail(void)
1283 {
1284 int size, ptr, i;
1285 uschar *s, *sep;
1286
1287 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
1288 return;
1289
1290 s = NULL;
1291 size = ptr = 0;
1292
1293 if (sender_host_authenticated != NULL)
1294 {
1295 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1296 if (authenticated_id != NULL)
1297 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1298 }
1299
1300 #ifdef SUPPORT_TLS
1301 s = s_tlslog(s, &size, &ptr);
1302 #endif
1303
1304 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1305 US" C=..." : US" C=";
1306 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1307 {
1308 if (smtp_connection_had[i] != SCH_NONE)
1309 {
1310 s = string_append(s, &size, &ptr, 2, sep,
1311 smtp_names[smtp_connection_had[i]]);
1312 sep = US",";
1313 }
1314 }
1315
1316 for (i = 0; i < smtp_ch_index; i++)
1317 {
1318 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1319 sep = US",";
1320 }
1321
1322 if (s != NULL) s[ptr] = 0; else s = US"";
1323 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1324 host_and_ident(FALSE),
1325 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1326 s);
1327 }
1328
1329
1330
1331 /*************************************************
1332 * Check HELO line and set sender_helo_name *
1333 *************************************************/
1334
1335 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1336 the domain name of the sending host, or an ip literal in square brackets. The
1337 arrgument is placed in sender_helo_name, which is in malloc store, because it
1338 must persist over multiple incoming messages. If helo_accept_junk is set, this
1339 host is permitted to send any old junk (needed for some broken hosts).
1340 Otherwise, helo_allow_chars can be used for rogue characters in general
1341 (typically people want to let in underscores).
1342
1343 Argument:
1344 s the data portion of the line (already past any white space)
1345
1346 Returns: TRUE or FALSE
1347 */
1348
1349 static BOOL
1350 check_helo(uschar *s)
1351 {
1352 uschar *start = s;
1353 uschar *end = s + Ustrlen(s);
1354 BOOL yield = helo_accept_junk;
1355
1356 /* Discard any previous helo name */
1357
1358 if (sender_helo_name != NULL)
1359 {
1360 store_free(sender_helo_name);
1361 sender_helo_name = NULL;
1362 }
1363
1364 /* Skip tests if junk is permitted. */
1365
1366 if (!yield)
1367 {
1368 /* Allow the new standard form for IPv6 address literals, namely,
1369 [IPv6:....], and because someone is bound to use it, allow an equivalent
1370 IPv4 form. Allow plain addresses as well. */
1371
1372 if (*s == '[')
1373 {
1374 if (end[-1] == ']')
1375 {
1376 end[-1] = 0;
1377 if (strncmpic(s, US"[IPv6:", 6) == 0)
1378 yield = (string_is_ip_address(s+6, NULL) == 6);
1379 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1380 yield = (string_is_ip_address(s+6, NULL) == 4);
1381 else
1382 yield = (string_is_ip_address(s+1, NULL) != 0);
1383 end[-1] = ']';
1384 }
1385 }
1386
1387 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1388 that have been configured (usually underscore - sigh). */
1389
1390 else if (*s != 0)
1391 {
1392 yield = TRUE;
1393 while (*s != 0)
1394 {
1395 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1396 Ustrchr(helo_allow_chars, *s) == NULL)
1397 {
1398 yield = FALSE;
1399 break;
1400 }
1401 s++;
1402 }
1403 }
1404 }
1405
1406 /* Save argument if OK */
1407
1408 if (yield) sender_helo_name = string_copy_malloc(start);
1409 return yield;
1410 }
1411
1412
1413
1414
1415
1416 /*************************************************
1417 * Extract SMTP command option *
1418 *************************************************/
1419
1420 /* This function picks the next option setting off the end of smtp_cmd_data. It
1421 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1422 things that can appear there.
1423
1424 Arguments:
1425 name point this at the name
1426 value point this at the data string
1427
1428 Returns: TRUE if found an option
1429 */
1430
1431 static BOOL
1432 extract_option(uschar **name, uschar **value)
1433 {
1434 uschar *n;
1435 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1436 while (isspace(*v)) v--;
1437 v[1] = 0;
1438 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1439
1440 n = v;
1441 if (*v == '=')
1442 {
1443 while(isalpha(n[-1])) n--;
1444 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1445 if (!isspace(n[-1])) return FALSE;
1446 n[-1] = 0;
1447 }
1448 else
1449 {
1450 n++;
1451 if (v == smtp_cmd_data) return FALSE;
1452 }
1453 *v++ = 0;
1454 *name = n;
1455 *value = v;
1456 return TRUE;
1457 }
1458
1459
1460
1461
1462
1463 /*************************************************
1464 * Reset for new message *
1465 *************************************************/
1466
1467 /* This function is called whenever the SMTP session is reset from
1468 within either of the setup functions.
1469
1470 Argument: the stacking pool storage reset point
1471 Returns: nothing
1472 */
1473
1474 static void
1475 smtp_reset(void *reset_point)
1476 {
1477 store_reset(reset_point);
1478 recipients_list = NULL;
1479 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1480 raw_recipients_count = recipients_count = recipients_list_max = 0;
1481 cancel_cutthrough_connection("smtp reset");
1482 message_linecount = 0;
1483 message_size = -1;
1484 acl_added_headers = NULL;
1485 acl_removed_headers = NULL;
1486 queue_only_policy = FALSE;
1487 rcpt_smtp_response = NULL;
1488 rcpt_smtp_response_same = TRUE;
1489 rcpt_in_progress = FALSE;
1490 deliver_freeze = FALSE; /* Can be set by ACL */
1491 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1492 fake_response = OK; /* Can be set by ACL */
1493 #ifdef WITH_CONTENT_SCAN
1494 no_mbox_unspool = FALSE; /* Can be set by ACL */
1495 #endif
1496 submission_mode = FALSE; /* Can be set by ACL */
1497 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1498 active_local_from_check = local_from_check; /* Can be set by ACL */
1499 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1500 sender_address = NULL;
1501 submission_name = NULL; /* Can be set by ACL */
1502 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1503 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1504 sender_verified_list = NULL; /* No senders verified */
1505 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1506 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1507
1508 prdr_requested = FALSE;
1509
1510 /* Reset the DSN flags */
1511 dsn_ret = 0;
1512 dsn_envid = NULL;
1513
1514 authenticated_sender = NULL;
1515 #ifdef EXPERIMENTAL_BRIGHTMAIL
1516 bmi_run = 0;
1517 bmi_verdicts = NULL;
1518 #endif
1519 #ifndef DISABLE_DKIM
1520 dkim_signers = NULL;
1521 dkim_disable_verify = FALSE;
1522 dkim_collect_input = FALSE;
1523 #endif
1524 #ifdef EXPERIMENTAL_SPF
1525 spf_header_comment = NULL;
1526 spf_received = NULL;
1527 spf_result = NULL;
1528 spf_smtp_comment = NULL;
1529 #endif
1530 #ifdef EXPERIMENTAL_INTERNATIONAL
1531 message_smtputf8 = FALSE;
1532 #endif
1533 body_linecount = body_zerocount = 0;
1534
1535 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1536 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1537 /* Note that ratelimiters_conn persists across resets. */
1538
1539 /* Reset message ACL variables */
1540
1541 acl_var_m = NULL;
1542
1543 /* The message body variables use malloc store. They may be set if this is
1544 not the first message in an SMTP session and the previous message caused them
1545 to be referenced in an ACL. */
1546
1547 if (message_body != NULL)
1548 {
1549 store_free(message_body);
1550 message_body = NULL;
1551 }
1552
1553 if (message_body_end != NULL)
1554 {
1555 store_free(message_body_end);
1556 message_body_end = NULL;
1557 }
1558
1559 /* Warning log messages are also saved in malloc store. They are saved to avoid
1560 repetition in the same message, but it seems right to repeat them for different
1561 messages. */
1562
1563 while (acl_warn_logged != NULL)
1564 {
1565 string_item *this = acl_warn_logged;
1566 acl_warn_logged = acl_warn_logged->next;
1567 store_free(this);
1568 }
1569 }
1570
1571
1572
1573
1574
1575 /*************************************************
1576 * Initialize for incoming batched SMTP message *
1577 *************************************************/
1578
1579 /* This function is called from smtp_setup_msg() in the case when
1580 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1581 of messages in one file with SMTP commands between them. All errors must be
1582 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1583 relevant. After an error on a sender, or an invalid recipient, the remainder
1584 of the message is skipped. The value of received_protocol is already set.
1585
1586 Argument: none
1587 Returns: > 0 message successfully started (reached DATA)
1588 = 0 QUIT read or end of file reached
1589 < 0 should not occur
1590 */
1591
1592 static int
1593 smtp_setup_batch_msg(void)
1594 {
1595 int done = 0;
1596 void *reset_point = store_get(0);
1597
1598 /* Save the line count at the start of each transaction - single commands
1599 like HELO and RSET count as whole transactions. */
1600
1601 bsmtp_transaction_linecount = receive_linecount;
1602
1603 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1604
1605 smtp_reset(reset_point); /* Reset for start of message */
1606
1607 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1608 value. The values are 2 larger than the required yield of the function. */
1609
1610 while (done <= 0)
1611 {
1612 uschar *errmess;
1613 uschar *recipient = NULL;
1614 int start, end, sender_domain, recipient_domain;
1615
1616 switch(smtp_read_command(FALSE))
1617 {
1618 /* The HELO/EHLO commands set sender_address_helo if they have
1619 valid data; otherwise they are ignored, except that they do
1620 a reset of the state. */
1621
1622 case HELO_CMD:
1623 case EHLO_CMD:
1624
1625 check_helo(smtp_cmd_data);
1626 /* Fall through */
1627
1628 case RSET_CMD:
1629 smtp_reset(reset_point);
1630 bsmtp_transaction_linecount = receive_linecount;
1631 break;
1632
1633
1634 /* The MAIL FROM command requires an address as an operand. All we
1635 do here is to parse it for syntactic correctness. The form "<>" is
1636 a special case which converts into an empty string. The start/end
1637 pointers in the original are not used further for this address, as
1638 it is the canonical extracted address which is all that is kept. */
1639
1640 case MAIL_CMD:
1641 if (sender_address != NULL)
1642 /* The function moan_smtp_batch() does not return. */
1643 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1644
1645 if (smtp_cmd_data[0] == 0)
1646 /* The function moan_smtp_batch() does not return. */
1647 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1648
1649 /* Reset to start of message */
1650
1651 smtp_reset(reset_point);
1652
1653 /* Apply SMTP rewrite */
1654
1655 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1656 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1657 US"", global_rewrite_rules) : smtp_cmd_data;
1658
1659 /* Extract the address; the TRUE flag allows <> as valid */
1660
1661 raw_sender =
1662 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1663 TRUE);
1664
1665 if (raw_sender == NULL)
1666 /* The function moan_smtp_batch() does not return. */
1667 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1668
1669 sender_address = string_copy(raw_sender);
1670
1671 /* Qualify unqualified sender addresses if permitted to do so. */
1672
1673 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1674 {
1675 if (allow_unqualified_sender)
1676 {
1677 sender_address = rewrite_address_qualify(sender_address, FALSE);
1678 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1679 "and rewritten\n", raw_sender);
1680 }
1681 /* The function moan_smtp_batch() does not return. */
1682 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1683 "a domain");
1684 }
1685 break;
1686
1687
1688 /* The RCPT TO command requires an address as an operand. All we do
1689 here is to parse it for syntactic correctness. There may be any number
1690 of RCPT TO commands, specifying multiple senders. We build them all into
1691 a data structure that is in argc/argv format. The start/end values
1692 given by parse_extract_address are not used, as we keep only the
1693 extracted address. */
1694
1695 case RCPT_CMD:
1696 if (sender_address == NULL)
1697 /* The function moan_smtp_batch() does not return. */
1698 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1699
1700 if (smtp_cmd_data[0] == 0)
1701 /* The function moan_smtp_batch() does not return. */
1702 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1703
1704 /* Check maximum number allowed */
1705
1706 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1707 /* The function moan_smtp_batch() does not return. */
1708 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1709 recipients_max_reject? "552": "452");
1710
1711 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1712 recipient address */
1713
1714 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1715 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1716 global_rewrite_rules) : smtp_cmd_data;
1717
1718 /* rfc821_domains = TRUE; << no longer needed */
1719 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1720 &recipient_domain, FALSE);
1721 /* rfc821_domains = FALSE; << no longer needed */
1722
1723 if (recipient == NULL)
1724 /* The function moan_smtp_batch() does not return. */
1725 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1726
1727 /* If the recipient address is unqualified, qualify it if permitted. Then
1728 add it to the list of recipients. */
1729
1730 if (recipient_domain == 0)
1731 {
1732 if (allow_unqualified_recipient)
1733 {
1734 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1735 recipient);
1736 recipient = rewrite_address_qualify(recipient, TRUE);
1737 }
1738 /* The function moan_smtp_batch() does not return. */
1739 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1740 "a domain");
1741 }
1742 receive_add_recipient(recipient, -1);
1743 break;
1744
1745
1746 /* The DATA command is legal only if it follows successful MAIL FROM
1747 and RCPT TO commands. This function is complete when a valid DATA
1748 command is encountered. */
1749
1750 case DATA_CMD:
1751 if (sender_address == NULL || recipients_count <= 0)
1752 {
1753 /* The function moan_smtp_batch() does not return. */
1754 if (sender_address == NULL)
1755 moan_smtp_batch(smtp_cmd_buffer,
1756 "503 MAIL FROM:<sender> command must precede DATA");
1757 else
1758 moan_smtp_batch(smtp_cmd_buffer,
1759 "503 RCPT TO:<recipient> must precede DATA");
1760 }
1761 else
1762 {
1763 done = 3; /* DATA successfully achieved */
1764 message_ended = END_NOTENDED; /* Indicate in middle of message */
1765 }
1766 break;
1767
1768
1769 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1770
1771 case VRFY_CMD:
1772 case EXPN_CMD:
1773 case HELP_CMD:
1774 case NOOP_CMD:
1775 case ETRN_CMD:
1776 bsmtp_transaction_linecount = receive_linecount;
1777 break;
1778
1779
1780 case EOF_CMD:
1781 case QUIT_CMD:
1782 done = 2;
1783 break;
1784
1785
1786 case BADARG_CMD:
1787 /* The function moan_smtp_batch() does not return. */
1788 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1789 break;
1790
1791
1792 case BADCHAR_CMD:
1793 /* The function moan_smtp_batch() does not return. */
1794 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1795 break;
1796
1797
1798 default:
1799 /* The function moan_smtp_batch() does not return. */
1800 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1801 break;
1802 }
1803 }
1804
1805 return done - 2; /* Convert yield values */
1806 }
1807
1808
1809
1810
1811 /*************************************************
1812 * Start an SMTP session *
1813 *************************************************/
1814
1815 /* This function is called at the start of an SMTP session. Thereafter,
1816 smtp_setup_msg() is called to initiate each separate message. This
1817 function does host-specific testing, and outputs the banner line.
1818
1819 Arguments: none
1820 Returns: FALSE if the session can not continue; something has
1821 gone wrong, or the connection to the host is blocked
1822 */
1823
1824 BOOL
1825 smtp_start_session(void)
1826 {
1827 int size = 256;
1828 int ptr, esclen;
1829 uschar *user_msg, *log_msg;
1830 uschar *code, *esc;
1831 uschar *p, *s, *ss;
1832
1833 smtp_connection_start = time(NULL);
1834 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1835 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1836 smtp_ch_index = 0;
1837
1838 /* Default values for certain variables */
1839
1840 helo_seen = esmtp = helo_accept_junk = FALSE;
1841 smtp_mailcmd_count = 0;
1842 count_nonmail = TRUE_UNSET;
1843 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1844 smtp_delay_mail = smtp_rlm_base;
1845 auth_advertised = FALSE;
1846 pipelining_advertised = FALSE;
1847 pipelining_enable = TRUE;
1848 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1849 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1850
1851 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1852
1853 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1854 authentication settings from -oMaa to remain in force. */
1855
1856 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1857 authenticated_by = NULL;
1858
1859 #ifdef SUPPORT_TLS
1860 tls_in.cipher = tls_in.peerdn = NULL;
1861 tls_in.ourcert = tls_in.peercert = NULL;
1862 tls_in.sni = NULL;
1863 tls_in.ocsp = OCSP_NOT_REQ;
1864 tls_advertised = FALSE;
1865 #endif
1866 dsn_advertised = FALSE;
1867 #ifdef EXPERIMENTAL_INTERNATIONAL
1868 smtputf8_advertised = FALSE;
1869 #endif
1870
1871 /* Reset ACL connection variables */
1872
1873 acl_var_c = NULL;
1874
1875 /* Allow for trailing 0 in the command and data buffers. */
1876
1877 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1878 if (smtp_cmd_buffer == NULL)
1879 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1880 "malloc() failed for SMTP command buffer");
1881 smtp_cmd_buffer[0] = 0;
1882 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1883
1884 /* For batched input, the protocol setting can be overridden from the
1885 command line by a trusted caller. */
1886
1887 if (smtp_batched_input)
1888 {
1889 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1890 }
1891
1892 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1893 reset later if any of EHLO/AUTH/STARTTLS are received. */
1894
1895 else
1896 received_protocol =
1897 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1898
1899 /* Set up the buffer for inputting using direct read() calls, and arrange to
1900 call the local functions instead of the standard C ones. */
1901
1902 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1903 if (smtp_inbuffer == NULL)
1904 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1905 receive_getc = smtp_getc;
1906 receive_ungetc = smtp_ungetc;
1907 receive_feof = smtp_feof;
1908 receive_ferror = smtp_ferror;
1909 receive_smtp_buffered = smtp_buffered;
1910 smtp_inptr = smtp_inend = smtp_inbuffer;
1911 smtp_had_eof = smtp_had_error = 0;
1912
1913 /* Set up the message size limit; this may be host-specific */
1914
1915 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1916 if (expand_string_message != NULL)
1917 {
1918 if (thismessage_size_limit == -1)
1919 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1920 "%s", expand_string_message);
1921 else
1922 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1923 "%s", expand_string_message);
1924 smtp_closedown(US"Temporary local problem - please try later");
1925 return FALSE;
1926 }
1927
1928 /* When a message is input locally via the -bs or -bS options, sender_host_
1929 unknown is set unless -oMa was used to force an IP address, in which case it
1930 is checked like a real remote connection. When -bs is used from inetd, this
1931 flag is not set, causing the sending host to be checked. The code that deals
1932 with IP source routing (if configured) is never required for -bs or -bS and
1933 the flag sender_host_notsocket is used to suppress it.
1934
1935 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1936 reserve for certain hosts and/or networks. */
1937
1938 if (!sender_host_unknown)
1939 {
1940 int rc;
1941 BOOL reserved_host = FALSE;
1942
1943 /* Look up IP options (source routing info) on the socket if this is not an
1944 -oMa "host", and if any are found, log them and drop the connection.
1945
1946 Linux (and others now, see below) is different to everyone else, so there
1947 has to be some conditional compilation here. Versions of Linux before 2.1.15
1948 used a structure whose name was "options". Somebody finally realized that
1949 this name was silly, and it got changed to "ip_options". I use the
1950 newer name here, but there is a fudge in the script that sets up os.h
1951 to define a macro in older Linux systems.
1952
1953 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1954 glibc 2, which has chosen ip_opts for the structure name. This is now
1955 really a glibc thing rather than a Linux thing, so the condition name
1956 has been changed to reflect this. It is relevant also to GNU/Hurd.
1957
1958 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1959 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1960 a special macro defined in the os.h file.
1961
1962 Some DGUX versions on older hardware appear not to support IP options at
1963 all, so there is now a general macro which can be set to cut out this
1964 support altogether.
1965
1966 How to do this properly in IPv6 is not yet known. */
1967
1968 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1969
1970 #ifdef GLIBC_IP_OPTIONS
1971 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1972 #define OPTSTYLE 1
1973 #else
1974 #define OPTSTYLE 2
1975 #endif
1976 #elif defined DARWIN_IP_OPTIONS
1977 #define OPTSTYLE 2
1978 #else
1979 #define OPTSTYLE 3
1980 #endif
1981
1982 if (!host_checking && !sender_host_notsocket)
1983 {
1984 #if OPTSTYLE == 1
1985 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1986 struct ip_options *ipopt = store_get(optlen);
1987 #elif OPTSTYLE == 2
1988 struct ip_opts ipoptblock;
1989 struct ip_opts *ipopt = &ipoptblock;
1990 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1991 #else
1992 struct ipoption ipoptblock;
1993 struct ipoption *ipopt = &ipoptblock;
1994 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1995 #endif
1996
1997 /* Occasional genuine failures of getsockopt() have been seen - for
1998 example, "reset by peer". Therefore, just log and give up on this
1999 call, unless the error is ENOPROTOOPT. This error is given by systems
2000 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2001 of writing. So for that error, carry on - we just can't do an IP options
2002 check. */
2003
2004 DEBUG(D_receive) debug_printf("checking for IP options\n");
2005
2006 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2007 &optlen) < 0)
2008 {
2009 if (errno != ENOPROTOOPT)
2010 {
2011 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2012 host_and_ident(FALSE), strerror(errno));
2013 smtp_printf("451 SMTP service not available\r\n");
2014 return FALSE;
2015 }
2016 }
2017
2018 /* Deal with any IP options that are set. On the systems I have looked at,
2019 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2020 more logging data than will fit in big_buffer. Nevertheless, after somebody
2021 questioned this code, I've added in some paranoid checking. */
2022
2023 else if (optlen > 0)
2024 {
2025 uschar *p = big_buffer;
2026 uschar *pend = big_buffer + big_buffer_size;
2027 uschar *opt, *adptr;
2028 int optcount;
2029 struct in_addr addr;
2030
2031 #if OPTSTYLE == 1
2032 uschar *optstart = (uschar *)(ipopt->__data);
2033 #elif OPTSTYLE == 2
2034 uschar *optstart = (uschar *)(ipopt->ip_opts);
2035 #else
2036 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2037 #endif
2038
2039 DEBUG(D_receive) debug_printf("IP options exist\n");
2040
2041 Ustrcpy(p, "IP options on incoming call:");
2042 p += Ustrlen(p);
2043
2044 for (opt = optstart; opt != NULL &&
2045 opt < (uschar *)(ipopt) + optlen;)
2046 {
2047 switch (*opt)
2048 {
2049 case IPOPT_EOL:
2050 opt = NULL;
2051 break;
2052
2053 case IPOPT_NOP:
2054 opt++;
2055 break;
2056
2057 case IPOPT_SSRR:
2058 case IPOPT_LSRR:
2059 if (!string_format(p, pend-p, " %s [@%s",
2060 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2061 #if OPTSTYLE == 1
2062 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2063 #elif OPTSTYLE == 2
2064 inet_ntoa(ipopt->ip_dst)))
2065 #else
2066 inet_ntoa(ipopt->ipopt_dst)))
2067 #endif
2068 {
2069 opt = NULL;
2070 break;
2071 }
2072
2073 p += Ustrlen(p);
2074 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2075 adptr = opt + 3;
2076 while (optcount-- > 0)
2077 {
2078 memcpy(&addr, adptr, sizeof(addr));
2079 if (!string_format(p, pend - p - 1, "%s%s",
2080 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2081 {
2082 opt = NULL;
2083 break;
2084 }
2085 p += Ustrlen(p);
2086 adptr += sizeof(struct in_addr);
2087 }
2088 *p++ = ']';
2089 opt += opt[1];
2090 break;
2091
2092 default:
2093 {
2094 int i;
2095 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2096 Ustrcat(p, "[ ");
2097 p += 2;
2098 for (i = 0; i < opt[1]; i++)
2099 {
2100 sprintf(CS p, "%2.2x ", opt[i]);
2101 p += 3;
2102 }
2103 *p++ = ']';
2104 }
2105 opt += opt[1];
2106 break;
2107 }
2108 }
2109
2110 *p = 0;
2111 log_write(0, LOG_MAIN, "%s", big_buffer);
2112
2113 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2114
2115 log_write(0, LOG_MAIN|LOG_REJECT,
2116 "connection from %s refused (IP options)", host_and_ident(FALSE));
2117
2118 smtp_printf("554 SMTP service not available\r\n");
2119 return FALSE;
2120 }
2121
2122 /* Length of options = 0 => there are no options */
2123
2124 else DEBUG(D_receive) debug_printf("no IP options found\n");
2125 }
2126 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2127
2128 /* Set keep-alive in socket options. The option is on by default. This
2129 setting is an attempt to get rid of some hanging connections that stick in
2130 read() when the remote end (usually a dialup) goes away. */
2131
2132 if (smtp_accept_keepalive && !sender_host_notsocket)
2133 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2134
2135 /* If the current host matches host_lookup, set the name by doing a
2136 reverse lookup. On failure, sender_host_name will be NULL and
2137 host_lookup_failed will be TRUE. This may or may not be serious - optional
2138 checks later. */
2139
2140 if (verify_check_host(&host_lookup) == OK)
2141 {
2142 (void)host_name_lookup();
2143 host_build_sender_fullhost();
2144 }
2145
2146 /* Delay this until we have the full name, if it is looked up. */
2147
2148 set_process_info("handling incoming connection from %s",
2149 host_and_ident(FALSE));
2150
2151 /* Expand smtp_receive_timeout, if needed */
2152
2153 if (smtp_receive_timeout_s)
2154 {
2155 uschar * exp;
2156 if ( !(exp = expand_string(smtp_receive_timeout_s))
2157 || !(*exp)
2158 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2159 )
2160 log_write(0, LOG_MAIN|LOG_PANIC,
2161 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2162 }
2163
2164 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2165 smtps port for use with older style SSL MTAs. */
2166
2167 #ifdef SUPPORT_TLS
2168 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2169 return FALSE;
2170 #endif
2171
2172 /* Test for explicit connection rejection */
2173
2174 if (verify_check_host(&host_reject_connection) == OK)
2175 {
2176 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2177 "from %s (host_reject_connection)", host_and_ident(FALSE));
2178 smtp_printf("554 SMTP service not available\r\n");
2179 return FALSE;
2180 }
2181
2182 /* Test with TCP Wrappers if so configured. There is a problem in that
2183 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2184 such as disks dying. In these cases, it is desirable to reject with a 4xx
2185 error instead of a 5xx error. There isn't a "right" way to detect such
2186 problems. The following kludge is used: errno is zeroed before calling
2187 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2188 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2189 not exist). */
2190
2191 #ifdef USE_TCP_WRAPPERS
2192 errno = 0;
2193 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2194 if (tcp_wrappers_name == NULL)
2195 {
2196 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2197 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2198 expand_string_message);
2199 }
2200 if (!hosts_ctl(tcp_wrappers_name,
2201 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2202 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2203 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2204 {
2205 if (errno == 0 || errno == ENOENT)
2206 {
2207 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2208 log_write(L_connection_reject,
2209 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2210 "(tcp wrappers)", host_and_ident(FALSE));
2211 smtp_printf("554 SMTP service not available\r\n");
2212 }
2213 else
2214 {
2215 int save_errno = errno;
2216 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2217 "errno value %d\n", save_errno);
2218 log_write(L_connection_reject,
2219 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2220 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2221 smtp_printf("451 Temporary local problem - please try later\r\n");
2222 }
2223 return FALSE;
2224 }
2225 #endif
2226
2227 /* Check for reserved slots. The value of smtp_accept_count has already been
2228 incremented to include this process. */
2229
2230 if (smtp_accept_max > 0 &&
2231 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2232 {
2233 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2234 {
2235 log_write(L_connection_reject,
2236 LOG_MAIN, "temporarily refused connection from %s: not in "
2237 "reserve list: connected=%d max=%d reserve=%d%s",
2238 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2239 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2240 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2241 "please try again later\r\n", smtp_active_hostname);
2242 return FALSE;
2243 }
2244 reserved_host = TRUE;
2245 }
2246
2247 /* If a load level above which only messages from reserved hosts are
2248 accepted is set, check the load. For incoming calls via the daemon, the
2249 check is done in the superior process if there are no reserved hosts, to
2250 save a fork. In all cases, the load average will already be available
2251 in a global variable at this point. */
2252
2253 if (smtp_load_reserve >= 0 &&
2254 load_average > smtp_load_reserve &&
2255 !reserved_host &&
2256 verify_check_host(&smtp_reserve_hosts) != OK)
2257 {
2258 log_write(L_connection_reject,
2259 LOG_MAIN, "temporarily refused connection from %s: not in "
2260 "reserve list and load average = %.2f", host_and_ident(FALSE),
2261 (double)load_average/1000.0);
2262 smtp_printf("421 %s: Too much load; please try again later\r\n",
2263 smtp_active_hostname);
2264 return FALSE;
2265 }
2266
2267 /* Determine whether unqualified senders or recipients are permitted
2268 for this host. Unfortunately, we have to do this every time, in order to
2269 set the flags so that they can be inspected when considering qualifying
2270 addresses in the headers. For a site that permits no qualification, this
2271 won't take long, however. */
2272
2273 allow_unqualified_sender =
2274 verify_check_host(&sender_unqualified_hosts) == OK;
2275
2276 allow_unqualified_recipient =
2277 verify_check_host(&recipient_unqualified_hosts) == OK;
2278
2279 /* Determine whether HELO/EHLO is required for this host. The requirement
2280 can be hard or soft. */
2281
2282 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2283 if (!helo_required)
2284 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2285
2286 /* Determine whether this hosts is permitted to send syntactic junk
2287 after a HELO or EHLO command. */
2288
2289 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2290 }
2291
2292 /* For batch SMTP input we are now done. */
2293
2294 if (smtp_batched_input) return TRUE;
2295
2296 #ifdef EXPERIMENTAL_PROXY
2297 /* If valid Proxy Protocol source is connecting, set up session.
2298 * Failure will not allow any SMTP function other than QUIT. */
2299 proxy_session = FALSE;
2300 proxy_session_failed = FALSE;
2301 if (check_proxy_protocol_host())
2302 {
2303 if (setup_proxy_protocol_host() == FALSE)
2304 {
2305 proxy_session_failed = TRUE;
2306 DEBUG(D_receive)
2307 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2308 }
2309 else
2310 {
2311 sender_host_name = NULL;
2312 (void)host_name_lookup();
2313 host_build_sender_fullhost();
2314 }
2315 }
2316 #endif
2317
2318 /* Run the ACL if it exists */
2319
2320 user_msg = NULL;
2321 if (acl_smtp_connect != NULL)
2322 {
2323 int rc;
2324 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2325 &log_msg);
2326 if (rc != OK)
2327 {
2328 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2329 return FALSE;
2330 }
2331 }
2332
2333 /* Output the initial message for a two-way SMTP connection. It may contain
2334 newlines, which then cause a multi-line response to be given. */
2335
2336 code = US"220"; /* Default status code */
2337 esc = US""; /* Default extended status code */
2338 esclen = 0; /* Length of esc */
2339
2340 if (user_msg == NULL)
2341 {
2342 s = expand_string(smtp_banner);
2343 if (s == NULL)
2344 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2345 "failed: %s", smtp_banner, expand_string_message);
2346 }
2347 else
2348 {
2349 int codelen = 3;
2350 s = user_msg;
2351 smtp_message_code(&code, &codelen, &s, NULL);
2352 if (codelen > 4)
2353 {
2354 esc = code + 4;
2355 esclen = codelen - 4;
2356 }
2357 }
2358
2359 /* Remove any terminating newlines; might as well remove trailing space too */
2360
2361 p = s + Ustrlen(s);
2362 while (p > s && isspace(p[-1])) p--;
2363 *p = 0;
2364
2365 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2366 is all contained in a single IP packet. The original code wrote out the
2367 greeting using several calls to fprint/fputc, and on busy servers this could
2368 cause it to be split over more than one packet - which caused CC:Mail to fall
2369 over when it got the second part of the greeting after sending its first
2370 command. Sigh. To try to avoid this, build the complete greeting message
2371 first, and output it in one fell swoop. This gives a better chance of it
2372 ending up as a single packet. */
2373
2374 ss = store_get(size);
2375 ptr = 0;
2376
2377 p = s;
2378 do /* At least once, in case we have an empty string */
2379 {
2380 int len;
2381 uschar *linebreak = Ustrchr(p, '\n');
2382 ss = string_cat(ss, &size, &ptr, code, 3);
2383 if (linebreak == NULL)
2384 {
2385 len = Ustrlen(p);
2386 ss = string_cat(ss, &size, &ptr, US" ", 1);
2387 }
2388 else
2389 {
2390 len = linebreak - p;
2391 ss = string_cat(ss, &size, &ptr, US"-", 1);
2392 }
2393 ss = string_cat(ss, &size, &ptr, esc, esclen);
2394 ss = string_cat(ss, &size, &ptr, p, len);
2395 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
2396 p += len;
2397 if (linebreak != NULL) p++;
2398 }
2399 while (*p != 0);
2400
2401 ss[ptr] = 0; /* string_cat leaves room for this */
2402
2403 /* Before we write the banner, check that there is no input pending, unless
2404 this synchronisation check is disabled. */
2405
2406 if (!check_sync())
2407 {
2408 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2409 "synchronization error (input sent without waiting for greeting): "
2410 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2411 string_printing(smtp_inptr));
2412 smtp_printf("554 SMTP synchronization error\r\n");
2413 return FALSE;
2414 }
2415
2416 /* Now output the banner */
2417
2418 smtp_printf("%s", ss);
2419 return TRUE;
2420 }
2421
2422
2423
2424
2425
2426 /*************************************************
2427 * Handle SMTP syntax and protocol errors *
2428 *************************************************/
2429
2430 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2431 to do so. Then transmit the error response. The return value depends on the
2432 number of syntax and protocol errors in this SMTP session.
2433
2434 Arguments:
2435 type error type, given as a log flag bit
2436 code response code; <= 0 means don't send a response
2437 data data to reflect in the response (can be NULL)
2438 errmess the error message
2439
2440 Returns: -1 limit of syntax/protocol errors NOT exceeded
2441 +1 limit of syntax/protocol errors IS exceeded
2442
2443 These values fit in with the values of the "done" variable in the main
2444 processing loop in smtp_setup_msg(). */
2445
2446 static int
2447 synprot_error(int type, int code, uschar *data, uschar *errmess)
2448 {
2449 int yield = -1;
2450
2451 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2452 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2453 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2454
2455 if (++synprot_error_count > smtp_max_synprot_errors)
2456 {
2457 yield = 1;
2458 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2459 "syntax or protocol errors (last command was \"%s\")",
2460 host_and_ident(FALSE), smtp_cmd_buffer);
2461 }
2462
2463 if (code > 0)
2464 {
2465 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2466 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2467 if (yield == 1)
2468 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2469 }
2470
2471 return yield;
2472 }
2473
2474
2475
2476
2477 /*************************************************
2478 * Log incomplete transactions *
2479 *************************************************/
2480
2481 /* This function is called after a transaction has been aborted by RSET, QUIT,
2482 connection drops or other errors. It logs the envelope information received
2483 so far in order to preserve address verification attempts.
2484
2485 Argument: string to indicate what aborted the transaction
2486 Returns: nothing
2487 */
2488
2489 static void
2490 incomplete_transaction_log(uschar *what)
2491 {
2492 if (sender_address == NULL || /* No transaction in progress */
2493 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
2494 ) return;
2495
2496 /* Build list of recipients for logging */
2497
2498 if (recipients_count > 0)
2499 {
2500 int i;
2501 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2502 for (i = 0; i < recipients_count; i++)
2503 raw_recipients[i] = recipients_list[i].address;
2504 raw_recipients_count = recipients_count;
2505 }
2506
2507 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2508 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2509 }
2510
2511
2512
2513
2514 /*************************************************
2515 * Send SMTP response, possibly multiline *
2516 *************************************************/
2517
2518 /* There are, it seems, broken clients out there that cannot handle multiline
2519 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2520 output nothing for non-final calls, and only the first line for anything else.
2521
2522 Arguments:
2523 code SMTP code, may involve extended status codes
2524 codelen length of smtp code; if > 4 there's an ESC
2525 final FALSE if the last line isn't the final line
2526 msg message text, possibly containing newlines
2527
2528 Returns: nothing
2529 */
2530
2531 void
2532 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2533 {
2534 int esclen = 0;
2535 uschar *esc = US"";
2536
2537 if (!final && no_multiline_responses) return;
2538
2539 if (codelen > 4)
2540 {
2541 esc = code + 4;
2542 esclen = codelen - 4;
2543 }
2544
2545 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2546 have had the same. Note: this code is also present in smtp_printf(). It would
2547 be tidier to have it only in one place, but when it was added, it was easier to
2548 do it that way, so as not to have to mess with the code for the RCPT command,
2549 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2550
2551 if (rcpt_in_progress)
2552 {
2553 if (rcpt_smtp_response == NULL)
2554 rcpt_smtp_response = string_copy(msg);
2555 else if (rcpt_smtp_response_same &&
2556 Ustrcmp(rcpt_smtp_response, msg) != 0)
2557 rcpt_smtp_response_same = FALSE;
2558 rcpt_in_progress = FALSE;
2559 }
2560
2561 /* Not output the message, splitting it up into multiple lines if necessary. */
2562
2563 for (;;)
2564 {
2565 uschar *nl = Ustrchr(msg, '\n');
2566 if (nl == NULL)
2567 {
2568 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2569 return;
2570 }
2571 else if (nl[1] == 0 || no_multiline_responses)
2572 {
2573 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2574 (int)(nl - msg), msg);
2575 return;
2576 }
2577 else
2578 {
2579 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2580 msg = nl + 1;
2581 while (isspace(*msg)) msg++;
2582 }
2583 }
2584 }
2585
2586
2587
2588
2589 /*************************************************
2590 * Parse user SMTP message *
2591 *************************************************/
2592
2593 /* This function allows for user messages overriding the response code details
2594 by providing a suitable response code string at the start of the message
2595 user_msg. Check the message for starting with a response code and optionally an
2596 extended status code. If found, check that the first digit is valid, and if so,
2597 change the code pointer and length to use the replacement. An invalid code
2598 causes a panic log; in this case, if the log messages is the same as the user
2599 message, we must also adjust the value of the log message to show the code that
2600 is actually going to be used (the original one).
2601
2602 This function is global because it is called from receive.c as well as within
2603 this module.
2604
2605 Note that the code length returned includes the terminating whitespace
2606 character, which is always included in the regex match.
2607
2608 Arguments:
2609 code SMTP code, may involve extended status codes
2610 codelen length of smtp code; if > 4 there's an ESC
2611 msg message text
2612 log_msg optional log message, to be adjusted with the new SMTP code
2613
2614 Returns: nothing
2615 */
2616
2617 void
2618 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2619 {
2620 int n;
2621 int ovector[3];
2622
2623 if (msg == NULL || *msg == NULL) return;
2624
2625 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2626 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2627 if (n < 0) return;
2628
2629 if ((*msg)[0] != (*code)[0])
2630 {
2631 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2632 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2633 if (log_msg != NULL && *log_msg == *msg)
2634 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2635 }
2636 else
2637 {
2638 *code = *msg;
2639 *codelen = ovector[1]; /* Includes final space */
2640 }
2641 *msg += ovector[1]; /* Chop the code off the message */
2642 return;
2643 }
2644
2645
2646
2647
2648 /*************************************************
2649 * Handle an ACL failure *
2650 *************************************************/
2651
2652 /* This function is called when acl_check() fails. As well as calls from within
2653 this module, it is called from receive.c for an ACL after DATA. It sorts out
2654 logging the incident, and sets up the error response. A message containing
2655 newlines is turned into a multiline SMTP response, but for logging, only the
2656 first line is used.
2657
2658 There's a table of default permanent failure response codes to use in
2659 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2660 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2661 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2662 state, because there are broken clients that try VRFY before RCPT. A 5xx
2663 response should be given only when the address is positively known to be
2664 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2665 503.
2666
2667 From Exim 4.63, it is possible to override the response code details by
2668 providing a suitable response code string at the start of the message provided
2669 in user_msg. The code's first digit is checked for validity.
2670
2671 Arguments:
2672 where where the ACL was called from
2673 rc the failure code
2674 user_msg a message that can be included in an SMTP response
2675 log_msg a message for logging
2676
2677 Returns: 0 in most cases
2678 2 if the failure code was FAIL_DROP, in which case the
2679 SMTP connection should be dropped (this value fits with the
2680 "done" variable in smtp_setup_msg() below)
2681 */
2682
2683 int
2684 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2685 {
2686 BOOL drop = rc == FAIL_DROP;
2687 int codelen = 3;
2688 uschar *smtp_code;
2689 uschar *lognl;
2690 uschar *sender_info = US"";
2691 uschar *what =
2692 #ifdef WITH_CONTENT_SCAN
2693 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2694 #endif
2695 (where == ACL_WHERE_PREDATA)? US"DATA" :
2696 (where == ACL_WHERE_DATA)? US"after DATA" :
2697 #ifndef DISABLE_PRDR
2698 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2699 #endif
2700 (smtp_cmd_data == NULL)?
2701 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2702 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2703
2704 if (drop) rc = FAIL;
2705
2706 /* Set the default SMTP code, and allow a user message to change it. */
2707
2708 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2709 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2710
2711 /* We used to have sender_address here; however, there was a bug that was not
2712 updating sender_address after a rewrite during a verify. When this bug was
2713 fixed, sender_address at this point became the rewritten address. I'm not sure
2714 this is what should be logged, so I've changed to logging the unrewritten
2715 address to retain backward compatibility. */
2716
2717 #ifndef WITH_CONTENT_SCAN
2718 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2719 #else
2720 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2721 #endif
2722 {
2723 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2724 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2725 sender_host_authenticated ? US" A=" : US"",
2726 sender_host_authenticated ? sender_host_authenticated : US"",
2727 sender_host_authenticated && authenticated_id ? US":" : US"",
2728 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2729 );
2730 }
2731
2732 /* If there's been a sender verification failure with a specific message, and
2733 we have not sent a response about it yet, do so now, as a preliminary line for
2734 failures, but not defers. However, always log it for defer, and log it for fail
2735 unless the sender_verify_fail log selector has been turned off. */
2736
2737 if (sender_verified_failed != NULL &&
2738 !testflag(sender_verified_failed, af_sverify_told))
2739 {
2740 BOOL save_rcpt_in_progress = rcpt_in_progress;
2741 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2742
2743 setflag(sender_verified_failed, af_sverify_told);
2744
2745 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2746 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2747 host_and_ident(TRUE),
2748 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2749 sender_verified_failed->address,
2750 (sender_verified_failed->message == NULL)? US"" :
2751 string_sprintf(": %s", sender_verified_failed->message));
2752
2753 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2754 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2755 testflag(sender_verified_failed, af_verify_pmfail)?
2756 "Postmaster verification failed while checking <%s>\n%s\n"
2757 "Several RFCs state that you are required to have a postmaster\n"
2758 "mailbox for each mail domain. This host does not accept mail\n"
2759 "from domains whose servers reject the postmaster address."
2760 :
2761 testflag(sender_verified_failed, af_verify_nsfail)?
2762 "Callback setup failed while verifying <%s>\n%s\n"
2763 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2764 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2765 "RFC requirements, and stops you from receiving standard bounce\n"
2766 "messages. This host does not accept mail from domains whose servers\n"
2767 "refuse bounces."
2768 :
2769 "Verification failed for <%s>\n%s",
2770 sender_verified_failed->address,
2771 sender_verified_failed->user_message));
2772
2773 rcpt_in_progress = save_rcpt_in_progress;
2774 }
2775
2776 /* Sort out text for logging */
2777
2778 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2779 lognl = Ustrchr(log_msg, '\n');
2780 if (lognl != NULL) *lognl = 0;
2781
2782 /* Send permanent failure response to the command, but the code used isn't
2783 always a 5xx one - see comments at the start of this function. If the original
2784 rc was FAIL_DROP we drop the connection and yield 2. */
2785
2786 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2787 US"Administrative prohibition" : user_msg);
2788
2789 /* Send temporary failure response to the command. Don't give any details,
2790 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2791 verb, and for a header verify when smtp_return_error_details is set.
2792
2793 This conditional logic is all somewhat of a mess because of the odd
2794 interactions between temp_details and return_error_details. One day it should
2795 be re-implemented in a tidier fashion. */
2796
2797 else
2798 {
2799 if (acl_temp_details && user_msg != NULL)
2800 {
2801 if (smtp_return_error_details &&
2802 sender_verified_failed != NULL &&
2803 sender_verified_failed->message != NULL)
2804 {
2805 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2806 }
2807 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2808 }
2809 else
2810 smtp_respond(smtp_code, codelen, TRUE,
2811 US"Temporary local problem - please try later");
2812 }
2813
2814 /* Log the incident to the logs that are specified by log_reject_target
2815 (default main, reject). This can be empty to suppress logging of rejections. If
2816 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2817 is closing if required and return 2. */
2818
2819 if (log_reject_target != 0)
2820 {
2821 #ifdef SUPPORT_TLS
2822 uschar * s = s_tlslog(NULL, NULL, NULL);
2823 if (!s) s = US"";
2824 #else
2825 uschar * s = US"";
2826 #endif
2827 log_write(0, log_reject_target, "%s%s %s%srejected %s%s",
2828 host_and_ident(TRUE), s,
2829 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2830 }
2831
2832 if (!drop) return 0;
2833
2834 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2835 smtp_get_connection_info());
2836
2837 /* Run the not-quit ACL, but without any custom messages. This should not be a
2838 problem, because we get here only if some other ACL has issued "drop", and
2839 in that case, *its* custom messages will have been used above. */
2840
2841 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2842 return 2;
2843 }
2844
2845
2846
2847
2848 /*************************************************
2849 * Handle SMTP exit when QUIT is not given *
2850 *************************************************/
2851
2852 /* This function provides a logging/statistics hook for when an SMTP connection
2853 is dropped on the floor or the other end goes away. It's a global function
2854 because it's called from receive.c as well as this module. As well as running
2855 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2856 response, either with a custom message from the ACL, or using a default. There
2857 is one case, however, when no message is output - after "drop". In that case,
2858 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2859 passed to this function.
2860
2861 In case things go wrong while processing this function, causing an error that
2862 may re-enter this funtion, there is a recursion check.
2863
2864 Arguments:
2865 reason What $smtp_notquit_reason will be set to in the ACL;
2866 if NULL, the ACL is not run
2867 code The error code to return as part of the response
2868 defaultrespond The default message if there's no user_msg
2869
2870 Returns: Nothing
2871 */
2872
2873 void
2874 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2875 {
2876 int rc;
2877 uschar *user_msg = NULL;
2878 uschar *log_msg = NULL;
2879
2880 /* Check for recursive acll */
2881
2882 if (smtp_exit_function_called)
2883 {
2884 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2885 reason);
2886 return;
2887 }
2888 smtp_exit_function_called = TRUE;
2889
2890 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2891
2892 if (acl_smtp_notquit != NULL && reason != NULL)
2893 {
2894 smtp_notquit_reason = reason;
2895 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2896 &log_msg);
2897 if (rc == ERROR)
2898 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2899 log_msg);
2900 }
2901
2902 /* Write an SMTP response if we are expected to give one. As the default
2903 responses are all internal, they should always fit in the buffer, but code a
2904 warning, just in case. Note that string_vformat() still leaves a complete
2905 string, even if it is incomplete. */
2906
2907 if (code != NULL && defaultrespond != NULL)
2908 {
2909 if (user_msg == NULL)
2910 {
2911 uschar buffer[128];
2912 va_list ap;
2913 va_start(ap, defaultrespond);
2914 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2915 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2916 smtp_printf("%s %s\r\n", code, buffer);
2917 va_end(ap);
2918 }
2919 else
2920 smtp_respond(code, 3, TRUE, user_msg);
2921 mac_smtp_fflush();
2922 }
2923 }
2924
2925
2926
2927
2928 /*************************************************
2929 * Verify HELO argument *
2930 *************************************************/
2931
2932 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2933 matched. It is also called from ACL processing if verify = helo is used and
2934 verification was not previously tried (i.e. helo_try_verify_hosts was not
2935 matched). The result of its processing is to set helo_verified and
2936 helo_verify_failed. These variables should both be FALSE for this function to
2937 be called.
2938
2939 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2940 for IPv6 ::ffff: literals.
2941
2942 Argument: none
2943 Returns: TRUE if testing was completed;
2944 FALSE on a temporary failure
2945 */
2946
2947 BOOL
2948 smtp_verify_helo(void)
2949 {
2950 BOOL yield = TRUE;
2951
2952 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2953 sender_helo_name);
2954
2955 if (sender_helo_name == NULL)
2956 {
2957 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2958 }
2959
2960 /* Deal with the case of -bs without an IP address */
2961
2962 else if (sender_host_address == NULL)
2963 {
2964 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2965 helo_verified = TRUE;
2966 }
2967
2968 /* Deal with the more common case when there is a sending IP address */
2969
2970 else if (sender_helo_name[0] == '[')
2971 {
2972 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2973 Ustrlen(sender_host_address)) == 0;
2974
2975 #if HAVE_IPV6
2976 if (!helo_verified)
2977 {
2978 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2979 helo_verified = Ustrncmp(sender_helo_name + 1,
2980 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2981 }
2982 #endif
2983
2984 HDEBUG(D_receive)
2985 { if (helo_verified) debug_printf("matched host address\n"); }
2986 }
2987
2988 /* Do a reverse lookup if one hasn't already given a positive or negative
2989 response. If that fails, or the name doesn't match, try checking with a forward
2990 lookup. */
2991
2992 else
2993 {
2994 if (sender_host_name == NULL && !host_lookup_failed)
2995 yield = host_name_lookup() != DEFER;
2996
2997 /* If a host name is known, check it and all its aliases. */
2998
2999 if (sender_host_name != NULL)
3000 {
3001 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
3002
3003 if (helo_verified)
3004 {
3005 HDEBUG(D_receive) debug_printf("matched host name\n");
3006 }
3007 else
3008 {
3009 uschar **aliases = sender_host_aliases;
3010 while (*aliases != NULL)
3011 {
3012 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
3013 if (helo_verified) break;
3014 }
3015 HDEBUG(D_receive)
3016 {
3017 if (helo_verified)
3018 debug_printf("matched alias %s\n", *(--aliases));
3019 }
3020 }
3021 }
3022
3023 /* Final attempt: try a forward lookup of the helo name */
3024
3025 if (!helo_verified)
3026 {
3027 int rc;
3028 host_item h;
3029 h.name = sender_helo_name;
3030 h.address = NULL;
3031 h.mx = MX_NONE;
3032 h.next = NULL;
3033 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3034 sender_helo_name);
3035 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
3036 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3037 {
3038 host_item *hh = &h;
3039 while (hh != NULL)
3040 {
3041 if (Ustrcmp(hh->address, sender_host_address) == 0)
3042 {
3043 helo_verified = TRUE;
3044 HDEBUG(D_receive)
3045 debug_printf("IP address for %s matches calling address\n",
3046 sender_helo_name);
3047 break;
3048 }
3049 hh = hh->next;
3050 }
3051 }
3052 }
3053 }
3054
3055 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3056 return yield;
3057 }
3058
3059
3060
3061
3062 /*************************************************
3063 * Send user response message *
3064 *************************************************/
3065
3066 /* This function is passed a default response code and a user message. It calls
3067 smtp_message_code() to check and possibly modify the response code, and then
3068 calls smtp_respond() to transmit the response. I put this into a function
3069 just to avoid a lot of repetition.
3070
3071 Arguments:
3072 code the response code
3073 user_msg the user message
3074
3075 Returns: nothing
3076 */
3077
3078 static void
3079 smtp_user_msg(uschar *code, uschar *user_msg)
3080 {
3081 int len = 3;
3082 smtp_message_code(&code, &len, &user_msg, NULL);
3083 smtp_respond(code, len, TRUE, user_msg);
3084 }
3085
3086
3087
3088 /*************************************************
3089 * Initialize for SMTP incoming message *
3090 *************************************************/
3091
3092 /* This function conducts the initial dialogue at the start of an incoming SMTP
3093 message, and builds a list of recipients. However, if the incoming message
3094 is part of a batch (-bS option) a separate function is called since it would
3095 be messy having tests splattered about all over this function. This function
3096 therefore handles the case where interaction is occurring. The input and output
3097 files are set up in smtp_in and smtp_out.
3098
3099 The global recipients_list is set to point to a vector of recipient_item
3100 blocks, whose number is given by recipients_count. This is extended by the
3101 receive_add_recipient() function. The global variable sender_address is set to
3102 the sender's address. The yield is +1 if a message has been successfully
3103 started, 0 if a QUIT command was encountered or the connection was refused from
3104 the particular host, or -1 if the connection was lost.
3105
3106 Argument: none
3107
3108 Returns: > 0 message successfully started (reached DATA)
3109 = 0 QUIT read or end of file reached or call refused
3110 < 0 lost connection
3111 */
3112
3113 int
3114 smtp_setup_msg(void)
3115 {
3116 int done = 0;
3117 BOOL toomany = FALSE;
3118 BOOL discarded = FALSE;
3119 BOOL last_was_rej_mail = FALSE;
3120 BOOL last_was_rcpt = FALSE;
3121 void *reset_point = store_get(0);
3122
3123 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3124
3125 /* Reset for start of new message. We allow one RSET not to be counted as a
3126 nonmail command, for those MTAs that insist on sending it between every
3127 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3128 TLS between messages (an Exim client may do this if it has messages queued up
3129 for the host). Note: we do NOT reset AUTH at this point. */
3130
3131 smtp_reset(reset_point);
3132 message_ended = END_NOTSTARTED;
3133
3134 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3135 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3136 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3137 #ifdef SUPPORT_TLS
3138 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3139 #endif
3140
3141 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3142
3143 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3144
3145 /* Batched SMTP is handled in a different function. */
3146
3147 if (smtp_batched_input) return smtp_setup_batch_msg();
3148
3149 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3150 value. The values are 2 larger than the required yield of the function. */
3151
3152 while (done <= 0)
3153 {
3154 const uschar **argv;
3155 uschar *etrn_command;
3156 uschar *etrn_serialize_key;
3157 uschar *errmess;
3158 uschar *log_msg, *smtp_code;
3159 uschar *user_msg = NULL;
3160 uschar *recipient = NULL;
3161 uschar *hello = NULL;
3162 const uschar *set_id = NULL;
3163 uschar *s, *ss;
3164 BOOL was_rej_mail = FALSE;
3165 BOOL was_rcpt = FALSE;
3166 void (*oldsignal)(int);
3167 pid_t pid;
3168 int start, end, sender_domain, recipient_domain;
3169 int ptr, size, rc;
3170 int c, i;
3171 auth_instance *au;
3172 uschar *orcpt = NULL;
3173 int flags;
3174
3175 switch(smtp_read_command(TRUE))
3176 {
3177 /* The AUTH command is not permitted to occur inside a transaction, and may
3178 occur successfully only once per connection. Actually, that isn't quite
3179 true. When TLS is started, all previous information about a connection must
3180 be discarded, so a new AUTH is permitted at that time.
3181
3182 AUTH may only be used when it has been advertised. However, it seems that
3183 there are clients that send AUTH when it hasn't been advertised, some of
3184 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3185 So there's a get-out that allows this to happen.
3186
3187 AUTH is initially labelled as a "nonmail command" so that one occurrence
3188 doesn't get counted. We change the label here so that multiple failing
3189 AUTHS will eventually hit the nonmail threshold. */
3190
3191 case AUTH_CMD:
3192 HAD(SCH_AUTH);
3193 authentication_failed = TRUE;
3194 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3195
3196 if (!auth_advertised && !allow_auth_unadvertised)
3197 {
3198 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3199 US"AUTH command used when not advertised");
3200 break;
3201 }
3202 if (sender_host_authenticated != NULL)
3203 {
3204 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3205 US"already authenticated");
3206 break;
3207 }
3208 if (sender_address != NULL)
3209 {
3210 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3211 US"not permitted in mail transaction");
3212 break;
3213 }
3214
3215 /* Check the ACL */
3216
3217 if (acl_smtp_auth != NULL)
3218 {
3219 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
3220 if (rc != OK)
3221 {
3222 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3223 break;
3224 }
3225 }
3226
3227 /* Find the name of the requested authentication mechanism. */
3228
3229 s = smtp_cmd_data;
3230 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3231 {
3232 if (!isalnum(c) && c != '-' && c != '_')
3233 {
3234 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3235 US"invalid character in authentication mechanism name");
3236 goto COMMAND_LOOP;
3237 }
3238 smtp_cmd_data++;
3239 }
3240
3241 /* If not at the end of the line, we must be at white space. Terminate the
3242 name and move the pointer on to any data that may be present. */
3243
3244 if (*smtp_cmd_data != 0)
3245 {
3246 *smtp_cmd_data++ = 0;
3247 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3248 }
3249
3250 /* Search for an authentication mechanism which is configured for use
3251 as a server and which has been advertised (unless, sigh, allow_auth_
3252 unadvertised is set). */
3253
3254 for (au = auths; au != NULL; au = au->next)
3255 {
3256 if (strcmpic(s, au->public_name) == 0 && au->server &&
3257 (au->advertised || allow_auth_unadvertised)) break;
3258 }
3259
3260 if (au == NULL)
3261 {
3262 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3263 string_sprintf("%s authentication mechanism not supported", s));
3264 break;
3265 }
3266
3267 /* Run the checking code, passing the remainder of the command line as
3268 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3269 it as the only set numerical variable. The authenticator may set $auth<n>
3270 and also set other numeric variables. The $auth<n> variables are preferred
3271 nowadays; the numerical variables remain for backwards compatibility.
3272
3273 Afterwards, have a go at expanding the set_id string, even if
3274 authentication failed - for bad passwords it can be useful to log the
3275 userid. On success, require set_id to expand and exist, and put it in
3276 authenticated_id. Save this in permanent store, as the working store gets
3277 reset at HELO, RSET, etc. */
3278
3279 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3280 expand_nmax = 0;
3281 expand_nlength[0] = 0; /* $0 contains nothing */
3282
3283 c = (au->info->servercode)(au, smtp_cmd_data);
3284 if (au->set_id != NULL) set_id = expand_string(au->set_id);
3285 expand_nmax = -1; /* Reset numeric variables */
3286 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3287
3288 /* The value of authenticated_id is stored in the spool file and printed in
3289 log lines. It must not contain binary zeros or newline characters. In
3290 normal use, it never will, but when playing around or testing, this error
3291 can (did) happen. To guard against this, ensure that the id contains only
3292 printing characters. */
3293
3294 if (set_id != NULL) set_id = string_printing(set_id);
3295
3296 /* For the non-OK cases, set up additional logging data if set_id
3297 is not empty. */
3298
3299 if (c != OK)
3300 {
3301 if (set_id != NULL && *set_id != 0)
3302 set_id = string_sprintf(" (set_id=%s)", set_id);
3303 else set_id = US"";
3304 }
3305
3306 /* Switch on the result */
3307
3308 switch(c)
3309 {
3310 case OK:
3311 if (au->set_id == NULL || set_id != NULL) /* Complete success */
3312 {
3313 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
3314 sender_host_authenticated = au->name;
3315 authentication_failed = FALSE;
3316 authenticated_fail_id = NULL; /* Impossible to already be set? */
3317 received_protocol =
3318 protocols[pextend + pauthed + ((tls_in.active >= 0)? pcrpted:0)] +
3319 ((sender_host_address != NULL)? pnlocal : 0);
3320 s = ss = US"235 Authentication succeeded";
3321 authenticated_by = au;
3322 break;
3323 }
3324
3325 /* Authentication succeeded, but we failed to expand the set_id string.
3326 Treat this as a temporary error. */
3327
3328 auth_defer_msg = expand_string_message;
3329 /* Fall through */
3330
3331 case DEFER:
3332 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3333 s = string_sprintf("435 Unable to authenticate at present%s",
3334 auth_defer_user_msg);
3335 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3336 set_id, auth_defer_msg);
3337 break;
3338
3339 case BAD64:
3340 s = ss = US"501 Invalid base64 data";
3341 break;
3342
3343 case CANCELLED:
3344 s = ss = US"501 Authentication cancelled";
3345 break;
3346
3347 case UNEXPECTED:
3348 s = ss = US"553 Initial data not expected";
3349 break;
3350
3351 case FAIL:
3352 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3353 s = US"535 Incorrect authentication data";
3354 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3355 break;
3356
3357 default:
3358 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3359 s = US"435 Internal error";
3360 ss = string_sprintf("435 Internal error%s: return %d from authentication "
3361 "check", set_id, c);
3362 break;
3363 }
3364
3365 smtp_printf("%s\r\n", s);
3366 if (c != OK)
3367 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3368 au->name, host_and_ident(FALSE), ss);
3369
3370 break; /* AUTH_CMD */
3371
3372 /* The HELO/EHLO commands are permitted to appear in the middle of a
3373 session as well as at the beginning. They have the effect of a reset in
3374 addition to their other functions. Their absence at the start cannot be
3375 taken to be an error.
3376
3377 RFC 2821 says:
3378
3379 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3380 or 502 failure replies MUST be returned as appropriate. The SMTP
3381 server MUST stay in the same state after transmitting these replies
3382 that it was in before the EHLO was received.
3383
3384 Therefore, we do not do the reset until after checking the command for
3385 acceptability. This change was made for Exim release 4.11. Previously
3386 it did the reset first. */
3387
3388 case HELO_CMD:
3389 HAD(SCH_HELO);
3390 hello = US"HELO";
3391 esmtp = FALSE;
3392 goto HELO_EHLO;
3393
3394 case EHLO_CMD:
3395 HAD(SCH_EHLO);
3396 hello = US"EHLO";
3397 esmtp = TRUE;
3398
3399 HELO_EHLO: /* Common code for HELO and EHLO */
3400 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3401 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3402
3403 /* Reject the HELO if its argument was invalid or non-existent. A
3404 successful check causes the argument to be saved in malloc store. */
3405
3406 if (!check_helo(smtp_cmd_data))
3407 {
3408 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3409
3410 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3411 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3412 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3413 string_printing(smtp_cmd_argument));
3414
3415 if (++synprot_error_count > smtp_max_synprot_errors)
3416 {
3417 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3418 "syntax or protocol errors (last command was \"%s\")",
3419 host_and_ident(FALSE), smtp_cmd_buffer);
3420 done = 1;
3421 }
3422
3423 break;
3424 }
3425
3426 /* If sender_host_unknown is true, we have got here via the -bs interface,
3427 not called from inetd. Otherwise, we are running an IP connection and the
3428 host address will be set. If the helo name is the primary name of this
3429 host and we haven't done a reverse lookup, force one now. If helo_required
3430 is set, ensure that the HELO name matches the actual host. If helo_verify
3431 is set, do the same check, but softly. */
3432
3433 if (!sender_host_unknown)
3434 {
3435 BOOL old_helo_verified = helo_verified;
3436 uschar *p = smtp_cmd_data;
3437
3438 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3439 *p = 0;
3440
3441 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3442 because otherwise the log can be confusing. */
3443
3444 if (sender_host_name == NULL &&
3445 (deliver_domain = sender_helo_name, /* set $domain */
3446 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3447 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3448 (void)host_name_lookup();
3449
3450 /* Rebuild the fullhost info to include the HELO name (and the real name
3451 if it was looked up.) */
3452
3453 host_build_sender_fullhost(); /* Rebuild */
3454 set_process_info("handling%s incoming connection from %s",
3455 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3456
3457 /* Verify if configured. This doesn't give much security, but it does
3458 make some people happy to be able to do it. If helo_required is set,
3459 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3460 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3461 now obsolescent, since the verification can now be requested selectively
3462 at ACL time. */
3463
3464 helo_verified = helo_verify_failed = FALSE;
3465 if (helo_required || helo_verify)
3466 {
3467 BOOL tempfail = !smtp_verify_helo();
3468 if (!helo_verified)
3469 {
3470 if (helo_required)
3471 {
3472 smtp_printf("%d %s argument does not match calling host\r\n",
3473 tempfail? 451 : 550, hello);
3474 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3475 tempfail? "temporarily " : "",
3476 hello, sender_helo_name, host_and_ident(FALSE));
3477 helo_verified = old_helo_verified;
3478 break; /* End of HELO/EHLO processing */
3479 }
3480 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3481 "helo_try_verify_hosts\n", hello);
3482 }
3483 }
3484 }
3485
3486 #ifdef EXPERIMENTAL_SPF
3487 /* set up SPF context */
3488 spf_init(sender_helo_name, sender_host_address);
3489 #endif
3490
3491 /* Apply an ACL check if one is defined; afterwards, recheck
3492 synchronization in case the client started sending in a delay. */
3493
3494 if (acl_smtp_helo != NULL)
3495 {
3496 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
3497 if (rc != OK)
3498 {
3499 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3500 sender_helo_name = NULL;
3501 host_build_sender_fullhost(); /* Rebuild */
3502 break;
3503 }
3504 else if (!check_sync()) goto SYNC_FAILURE;
3505 }
3506
3507 /* Generate an OK reply. The default string includes the ident if present,
3508 and also the IP address if present. Reflecting back the ident is intended
3509 as a deterrent to mail forgers. For maximum efficiency, and also because
3510 some broken systems expect each response to be in a single packet, arrange
3511 that the entire reply is sent in one write(). */
3512
3513 auth_advertised = FALSE;
3514 pipelining_advertised = FALSE;
3515 #ifdef SUPPORT_TLS
3516 tls_advertised = FALSE;
3517 #endif
3518 dsn_advertised = FALSE;
3519 #ifdef EXPERIMENTAL_INTERNATIONAL
3520 smtputf8_advertised = FALSE;
3521 #endif
3522
3523 smtp_code = US"250 "; /* Default response code plus space*/
3524 if (user_msg == NULL)
3525 {
3526 s = string_sprintf("%.3s %s Hello %s%s%s",
3527 smtp_code,
3528 smtp_active_hostname,
3529 (sender_ident == NULL)? US"" : sender_ident,
3530 (sender_ident == NULL)? US"" : US" at ",
3531 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3532
3533 ptr = Ustrlen(s);
3534 size = ptr + 1;
3535
3536 if (sender_host_address != NULL)
3537 {
3538 s = string_cat(s, &size, &ptr, US" [", 2);
3539 s = string_cat(s, &size, &ptr, sender_host_address,
3540 Ustrlen(sender_host_address));
3541 s = string_cat(s, &size, &ptr, US"]", 1);
3542 }
3543 }
3544
3545 /* A user-supplied EHLO greeting may not contain more than one line. Note
3546 that the code returned by smtp_message_code() includes the terminating
3547 whitespace character. */
3548
3549 else
3550 {
3551 char *ss;
3552 int codelen = 4;
3553 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3554 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3555 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3556 {
3557 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3558 "newlines: message truncated: %s", string_printing(s));
3559 *ss = 0;
3560 }
3561 ptr = Ustrlen(s);
3562 size = ptr + 1;
3563 }
3564
3565 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3566
3567 /* If we received EHLO, we must create a multiline response which includes
3568 the functions supported. */
3569
3570 if (esmtp)
3571 {
3572 s[3] = '-';
3573
3574 /* I'm not entirely happy with this, as an MTA is supposed to check
3575 that it has enough room to accept a message of maximum size before
3576 it sends this. However, there seems little point in not sending it.
3577 The actual size check happens later at MAIL FROM time. By postponing it
3578 till then, VRFY and EXPN can be used after EHLO when space is short. */
3579
3580 if (thismessage_size_limit > 0)
3581 {
3582 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3583 thismessage_size_limit);
3584 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3585 }
3586 else
3587 {
3588 s = string_cat(s, &size, &ptr, smtp_code, 3);
3589 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3590 }
3591
3592 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3593 clean; if it has an 8-bit character in its hand, it just sends it. It
3594 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3595 However, some users want this option simply in order to stop MUAs
3596 mangling messages that contain top-bit-set characters. It is therefore
3597 provided as an option. */
3598
3599 if (accept_8bitmime)
3600 {
3601 s = string_cat(s, &size, &ptr, smtp_code, 3);
3602 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3603 }
3604
3605 /* Advertise DSN support if configured to do so. */
3606 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
3607 {
3608 s = string_cat(s, &size, &ptr, smtp_code, 3);
3609 s = string_cat(s, &size, &ptr, US"-DSN\r\n", 6);
3610 dsn_advertised = TRUE;
3611 }
3612
3613 /* Advertise ETRN if there's an ACL checking whether a host is
3614 permitted to issue it; a check is made when any host actually tries. */
3615
3616 if (acl_smtp_etrn != NULL)
3617 {
3618 s = string_cat(s, &size, &ptr, smtp_code, 3);
3619 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3620 }
3621
3622 /* Advertise EXPN if there's an ACL checking whether a host is
3623 permitted to issue it; a check is made when any host actually tries. */
3624
3625 if (acl_smtp_expn != NULL)
3626 {
3627 s = string_cat(s, &size, &ptr, smtp_code, 3);
3628 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3629 }
3630
3631 /* Exim is quite happy with pipelining, so let the other end know that
3632 it is safe to use it, unless advertising is disabled. */
3633
3634 if (pipelining_enable &&
3635 verify_check_host(&pipelining_advertise_hosts) == OK)
3636 {
3637 s = string_cat(s, &size, &ptr, smtp_code, 3);
3638 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3639 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3640 pipelining_advertised = TRUE;
3641 }
3642
3643
3644 /* If any server authentication mechanisms are configured, advertise
3645 them if the current host is in auth_advertise_hosts. The problem with
3646 advertising always is that some clients then require users to
3647 authenticate (and aren't configurable otherwise) even though it may not
3648 be necessary (e.g. if the host is in host_accept_relay).
3649
3650 RFC 2222 states that SASL mechanism names contain only upper case
3651 letters, so output the names in upper case, though we actually recognize
3652 them in either case in the AUTH command. */
3653
3654 if (auths != NULL)
3655 {
3656 if (verify_check_host(&auth_advertise_hosts) == OK)
3657 {
3658 auth_instance *au;
3659 BOOL first = TRUE;
3660 for (au = auths; au != NULL; au = au->next)
3661 {
3662 if (au->server && (au->advertise_condition == NULL ||
3663 expand_check_condition(au->advertise_condition, au->name,
3664 US"authenticator")))
3665 {
3666 int saveptr;
3667 if (first)
3668 {
3669 s = string_cat(s, &size, &ptr, smtp_code, 3);
3670 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3671 first = FALSE;
3672 auth_advertised = TRUE;
3673 }
3674 saveptr = ptr;
3675 s = string_cat(s, &size, &ptr, US" ", 1);
3676 s = string_cat(s, &size, &ptr, au->public_name,
3677 Ustrlen(au->public_name));
3678 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3679 au->advertised = TRUE;
3680 }
3681 else au->advertised = FALSE;
3682 }
3683 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3684 }
3685 }
3686
3687 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3688 if it has been included in the binary, and the host matches
3689 tls_advertise_hosts. We must *not* advertise if we are already in a
3690 secure connection. */
3691
3692 #ifdef SUPPORT_TLS
3693 if (tls_in.active < 0 &&
3694 verify_check_host(&tls_advertise_hosts) != FAIL)
3695 {
3696 s = string_cat(s, &size, &ptr, smtp_code, 3);
3697 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3698 tls_advertised = TRUE;
3699 }
3700 #endif
3701
3702 #ifndef DISABLE_PRDR
3703 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3704 if (prdr_enable)
3705 {
3706 s = string_cat(s, &size, &ptr, smtp_code, 3);
3707 s = string_cat(s, &size, &ptr, US"-PRDR\r\n", 7);
3708 }
3709 #endif
3710
3711 #ifdef EXPERIMENTAL_INTERNATIONAL
3712 if ( accept_8bitmime
3713 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
3714 {
3715 s = string_cat(s, &size, &ptr, smtp_code, 3);
3716 s = string_cat(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
3717 smtputf8_advertised = TRUE;
3718 }
3719 #endif
3720
3721 /* Finish off the multiline reply with one that is always available. */
3722
3723 s = string_cat(s, &size, &ptr, smtp_code, 3);
3724 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3725 }
3726
3727 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3728 has been seen. */
3729
3730 s[ptr] = 0;
3731
3732 #ifdef SUPPORT_TLS
3733 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
3734 #endif
3735
3736 {
3737 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
3738 }
3739 DEBUG(D_receive)
3740 {
3741 uschar *cr;
3742 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3743 memmove(cr, cr + 1, (ptr--) - (cr - s));
3744 debug_printf("SMTP>> %s", s);
3745 }
3746 helo_seen = TRUE;
3747
3748 /* Reset the protocol and the state, abandoning any previous message. */
3749
3750 received_protocol = (esmtp?
3751 protocols[pextend +
3752 ((sender_host_authenticated != NULL)? pauthed : 0) +
3753 ((tls_in.active >= 0)? pcrpted : 0)]
3754 :
3755 protocols[pnormal + ((tls_in.active >= 0)? pcrpted : 0)])
3756 +
3757 ((sender_host_address != NULL)? pnlocal : 0);
3758
3759 smtp_reset(reset_point);
3760 toomany = FALSE;
3761 break; /* HELO/EHLO */
3762
3763
3764 /* The MAIL command requires an address as an operand. All we do
3765 here is to parse it for syntactic correctness. The form "<>" is
3766 a special case which converts into an empty string. The start/end
3767 pointers in the original are not used further for this address, as
3768 it is the canonical extracted address which is all that is kept. */
3769
3770 case MAIL_CMD:
3771 HAD(SCH_MAIL);
3772 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3773 was_rej_mail = TRUE; /* Reset if accepted */
3774 env_mail_type_t * mail_args; /* Sanity check & validate args */
3775
3776 if (helo_required && !helo_seen)
3777 {
3778 smtp_printf("503 HELO or EHLO required\r\n");
3779 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3780 "HELO/EHLO given", host_and_ident(FALSE));
3781 break;
3782 }
3783
3784 if (sender_address != NULL)
3785 {
3786 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3787 US"sender already given");
3788 break;
3789 }
3790
3791 if (smtp_cmd_data[0] == 0)
3792 {
3793 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3794 US"MAIL must have an address operand");
3795 break;
3796 }
3797
3798 /* Check to see if the limit for messages per connection would be
3799 exceeded by accepting further messages. */
3800
3801 if (smtp_accept_max_per_connection > 0 &&
3802 smtp_mailcmd_count > smtp_accept_max_per_connection)
3803 {
3804 smtp_printf("421 too many messages in this connection\r\n");
3805 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3806 "messages in one connection", host_and_ident(TRUE));
3807 break;
3808 }
3809
3810 /* Reset for start of message - even if this is going to fail, we
3811 obviously need to throw away any previous data. */
3812
3813 smtp_reset(reset_point);
3814 toomany = FALSE;
3815 sender_data = recipient_data = NULL;
3816
3817 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3818
3819 if (esmtp) for(;;)
3820 {
3821 uschar *name, *value, *end;
3822 unsigned long int size;
3823 BOOL arg_error = FALSE;
3824
3825 if (!extract_option(&name, &value)) break;
3826
3827 for (mail_args = env_mail_type_list;
3828 (char *)mail_args < (char *)env_mail_type_list + sizeof(env_mail_type_list);
3829 mail_args++
3830 )
3831 {
3832 if (strcmpic(name, mail_args->name) == 0)
3833 break;
3834 }
3835 if (mail_args->need_value && strcmpic(value, US"") == 0)
3836 break;
3837
3838 switch(mail_args->value)
3839 {
3840 /* Handle SIZE= by reading the value. We don't do the check till later,
3841 in order to be able to log the sender address on failure. */
3842 case ENV_MAIL_OPT_SIZE:
3843 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
3844 {
3845 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3846 size = INT_MAX;
3847 message_size = (int)size;
3848 }
3849 else
3850 arg_error = TRUE;
3851 break;
3852
3853 /* If this session was initiated with EHLO and accept_8bitmime is set,
3854 Exim will have indicated that it supports the BODY=8BITMIME option. In
3855 fact, it does not support this according to the RFCs, in that it does not
3856 take any special action for forwarding messages containing 8-bit
3857 characters. That is why accept_8bitmime is not the default setting, but
3858 some sites want the action that is provided. We recognize both "8BITMIME"
3859 and "7BIT" as body types, but take no action. */
3860 case ENV_MAIL_OPT_BODY:
3861 if (accept_8bitmime) {
3862 if (strcmpic(value, US"8BITMIME") == 0) {
3863 body_8bitmime = 8;
3864 } else if (strcmpic(value, US"7BIT") == 0) {
3865 body_8bitmime = 7;
3866 } else {
3867 body_8bitmime = 0;
3868 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3869 US"invalid data for BODY");
3870 goto COMMAND_LOOP;
3871 }
3872 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
3873 break;
3874 }
3875 arg_error = TRUE;
3876 break;
3877
3878 /* Handle the two DSN options, but only if configured to do so (which
3879 will have caused "DSN" to be given in the EHLO response). The code itself
3880 is included only if configured in at build time. */
3881
3882 case ENV_MAIL_OPT_RET:
3883 if (dsn_advertised) {
3884 /* Check if RET has already been set */
3885 if (dsn_ret > 0) {
3886 synprot_error(L_smtp_syntax_error, 501, NULL,
3887 US"RET can be specified once only");
3888 goto COMMAND_LOOP;
3889 }
3890 dsn_ret = (strcmpic(value, US"HDRS") == 0)? dsn_ret_hdrs :
3891 (strcmpic(value, US"FULL") == 0)? dsn_ret_full : 0;
3892 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
3893 /* Check for invalid invalid value, and exit with error */
3894 if (dsn_ret == 0) {
3895 synprot_error(L_smtp_syntax_error, 501, NULL,
3896 US"Value for RET is invalid");
3897 goto COMMAND_LOOP;
3898 }
3899 }
3900 break;
3901 case ENV_MAIL_OPT_ENVID:
3902 if (dsn_advertised) {
3903 /* Check if the dsn envid has been already set */
3904 if (dsn_envid != NULL) {
3905 synprot_error(L_smtp_syntax_error, 501, NULL,
3906 US"ENVID can be specified once only");
3907 goto COMMAND_LOOP;
3908 }
3909 dsn_envid = string_copy(value);
3910 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
3911 }
3912 break;
3913
3914 /* Handle the AUTH extension. If the value given is not "<>" and either
3915 the ACL says "yes" or there is no ACL but the sending host is
3916 authenticated, we set it up as the authenticated sender. However, if the
3917 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3918 the condition is met. The value of AUTH is an xtext, which means that +,
3919 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3920 coding. */
3921 case ENV_MAIL_OPT_AUTH:
3922 if (Ustrcmp(value, "<>") != 0)
3923 {
3924 int rc;
3925 uschar *ignore_msg;
3926
3927 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3928 {
3929 /* Put back terminator overrides for error message */
3930 value[-1] = '=';
3931 name[-1] = ' ';
3932 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3933 US"invalid data for AUTH");
3934 goto COMMAND_LOOP;
3935 }
3936 if (acl_smtp_mailauth == NULL)
3937 {
3938 ignore_msg = US"client not authenticated";
3939 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3940 }
3941 else
3942 {
3943 ignore_msg = US"rejected by ACL";
3944 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3945 &user_msg, &log_msg);
3946 }
3947
3948 switch (rc)
3949 {
3950 case OK:
3951 if (authenticated_by == NULL ||
3952 authenticated_by->mail_auth_condition == NULL ||
3953 expand_check_condition(authenticated_by->mail_auth_condition,
3954 authenticated_by->name, US"authenticator"))
3955 break; /* Accept the AUTH */
3956
3957 ignore_msg = US"server_mail_auth_condition failed";
3958 if (authenticated_id != NULL)
3959 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3960 ignore_msg, authenticated_id);
3961
3962 /* Fall through */
3963
3964 case FAIL:
3965 authenticated_sender = NULL;
3966 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3967 value, host_and_ident(TRUE), ignore_msg);
3968 break;
3969
3970 /* Should only get DEFER or ERROR here. Put back terminator
3971 overrides for error message */
3972
3973 default:
3974 value[-1] = '=';
3975 name[-1] = ' ';
3976 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3977 log_msg);
3978 goto COMMAND_LOOP;
3979 }
3980 }
3981 break;
3982
3983 #ifndef DISABLE_PRDR
3984 case ENV_MAIL_OPT_PRDR:
3985 if (prdr_enable)
3986 prdr_requested = TRUE;
3987 break;
3988 #endif
3989
3990 #ifdef EXPERIMENTAL_INTERNATIONAL
3991 case ENV_MAIL_OPT_UTF8:
3992 if (smtputf8_advertised)
3993 message_smtputf8 = TRUE;
3994 break;
3995 #endif
3996 /* Unknown option. Stick back the terminator characters and break
3997 the loop. Do the name-terminator second as extract_option sets
3998 value==name when it found no equal-sign.
3999 An error for a malformed address will occur. */
4000 default:
4001 value[-1] = '=';
4002 name[-1] = ' ';
4003 arg_error = TRUE;
4004 break;
4005 }
4006 /* Break out of for loop if switch() had bad argument or
4007 when start of the email address is reached */
4008 if (arg_error) break;
4009 }
4010
4011 /* If we have passed the threshold for rate limiting, apply the current
4012 delay, and update it for next time, provided this is a limited host. */
4013
4014 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4015 verify_check_host(&smtp_ratelimit_hosts) == OK)
4016 {
4017 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4018 smtp_delay_mail/1000.0);
4019 millisleep((int)smtp_delay_mail);
4020 smtp_delay_mail *= smtp_rlm_factor;
4021 if (smtp_delay_mail > (double)smtp_rlm_limit)
4022 smtp_delay_mail = (double)smtp_rlm_limit;
4023 }
4024
4025 /* Now extract the address, first applying any SMTP-time rewriting. The
4026 TRUE flag allows "<>" as a sender address. */
4027
4028 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
4029 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4030 global_rewrite_rules) : smtp_cmd_data;
4031
4032 /* rfc821_domains = TRUE; << no longer needed */
4033 raw_sender =
4034 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4035 TRUE);
4036 /* rfc821_domains = FALSE; << no longer needed */
4037
4038 if (raw_sender == NULL)
4039 {
4040 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4041 break;
4042 }
4043
4044 sender_address = raw_sender;
4045
4046 /* If there is a configured size limit for mail, check that this message
4047 doesn't exceed it. The check is postponed to this point so that the sender
4048 can be logged. */
4049
4050 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4051 {
4052 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4053 log_write(L_size_reject,
4054 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4055 "message too big: size%s=%d max=%d",
4056 sender_address,
4057 host_and_ident(TRUE),
4058 (message_size == INT_MAX)? ">" : "",
4059 message_size,
4060 thismessage_size_limit);
4061 sender_address = NULL;
4062 break;
4063 }
4064
4065 /* Check there is enough space on the disk unless configured not to.
4066 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4067 plus the current message - i.e. we accept the message only if it won't
4068 reduce the space below the threshold. Add 5000 to the size to allow for
4069 overheads such as the Received: line and storing of recipients, etc.
4070 By putting the check here, even when SIZE is not given, it allow VRFY
4071 and EXPN etc. to be used when space is short. */
4072
4073 if (!receive_check_fs(
4074 (smtp_check_spool_space && message_size