Logging: dnssec status on accept & delivery lines
[exim.git] / src / src / smtp_in.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2016 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8 /* Functions for handling an incoming SMTP call. */
9
10
11 #include "exim.h"
12 #include <assert.h>
13
14
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
18
19 #ifdef USE_TCP_WRAPPERS
20
21 #if HAVE_IPV6
22 #define EXIM_HAVE_IPV6
23 #endif
24 #undef HAVE_IPV6
25 #include <tcpd.h>
26 #undef HAVE_IPV6
27 #ifdef EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
29 #endif
30
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
34 #endif
35
36
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
45 */
46
47 #define smtp_cmd_buffer_size 16384
48
49 /* Size of buffer for reading SMTP incoming packets */
50
51 #define in_buffer_size 8192
52
53 /* Structure for SMTP command list */
54
55 typedef struct {
56 const char *name;
57 int len;
58 short int cmd;
59 short int has_arg;
60 short int is_mail_cmd;
61 } smtp_cmd_list;
62
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
65 block some spam. */
66
67 enum {
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
70
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
76
77 /* This is a dummy to identify the non-sync commands when pipelining */
78
79 NON_SYNC_CMD_PIPELINING,
80
81 /* These commands need not be synchronized when pipelining */
82
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
84
85 /* This is a dummy to identify the non-sync commands when not pipelining */
86
87 NON_SYNC_CMD_NON_PIPELINING,
88
89 /* I have been unable to find a statement about the use of pipelining
90 with AUTH, so to be on the safe side it is here, though I kind of feel
91 it should be up there with the synchronized commands. */
92
93 AUTH_CMD,
94
95 /* I'm not sure about these, but I don't think they matter. */
96
97 QUIT_CMD, HELP_CMD,
98
99 #ifdef SUPPORT_PROXY
100 PROXY_FAIL_IGNORE_CMD,
101 #endif
102
103 /* These are specials that don't correspond to actual commands */
104
105 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
106 TOO_MANY_NONMAIL_CMD };
107
108
109 /* This is a convenience macro for adding the identity of an SMTP command
110 to the circular buffer that holds a list of the last n received. */
111
112 #define HAD(n) \
113 smtp_connection_had[smtp_ch_index++] = n; \
114 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
115
116
117 /*************************************************
118 * Local static variables *
119 *************************************************/
120
121 static auth_instance *authenticated_by;
122 static BOOL auth_advertised;
123 #ifdef SUPPORT_TLS
124 static BOOL tls_advertised;
125 #endif
126 static BOOL dsn_advertised;
127 static BOOL esmtp;
128 static BOOL helo_required = FALSE;
129 static BOOL helo_verify = FALSE;
130 static BOOL helo_seen;
131 static BOOL helo_accept_junk;
132 static BOOL count_nonmail;
133 static BOOL pipelining_advertised;
134 static BOOL rcpt_smtp_response_same;
135 static BOOL rcpt_in_progress;
136 static int nonmail_command_count;
137 static BOOL smtp_exit_function_called = 0;
138 #ifdef SUPPORT_I18N
139 static BOOL smtputf8_advertised;
140 #endif
141 static int synprot_error_count;
142 static int unknown_command_count;
143 static int sync_cmd_limit;
144 static int smtp_write_error = 0;
145
146 static uschar *rcpt_smtp_response;
147 static uschar *smtp_data_buffer;
148 static uschar *smtp_cmd_data;
149
150 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
151 final fields of all except AUTH are forced TRUE at the start of a new message
152 setup, to allow one of each between messages that is not counted as a nonmail
153 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
154 allow a new EHLO after starting up TLS.
155
156 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
157 counted. However, the flag is changed when AUTH is received, so that multiple
158 failing AUTHs will eventually hit the limit. After a successful AUTH, another
159 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
160 forced TRUE, to allow for the re-authentication that can happen at that point.
161
162 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
163 count of non-mail commands and possibly provoke an error.
164
165 tls_auth is a pseudo-command, never expected in input. It is activated
166 on TLS startup and looks for a tls authenticator. */
167
168 static smtp_cmd_list cmd_list[] = {
169 /* name len cmd has_arg is_mail_cmd */
170
171 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
172 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
173 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
174 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
175 #ifdef SUPPORT_TLS
176 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
177 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, TRUE },
178 #endif
179
180 /* If you change anything above here, also fix the definitions below. */
181
182 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
183 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
184 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
185 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
186 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
187 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
188 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
189 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
190 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
191 };
192
193 static smtp_cmd_list *cmd_list_end =
194 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
195
196 #define CMD_LIST_RSET 0
197 #define CMD_LIST_HELO 1
198 #define CMD_LIST_EHLO 2
199 #define CMD_LIST_AUTH 3
200 #define CMD_LIST_STARTTLS 4
201 #define CMD_LIST_TLS_AUTH 5
202
203 /* This list of names is used for performing the smtp_no_mail logging action.
204 It must be kept in step with the SCH_xxx enumerations. */
205
206 static uschar *smtp_names[] =
207 {
208 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
209 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
210 US"VRFY" };
211
212 static uschar *protocols_local[] = {
213 US"local-smtp", /* HELO */
214 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
215 US"local-esmtp", /* EHLO */
216 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
217 US"local-esmtpa", /* EHLO->AUTH */
218 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
219 };
220 static uschar *protocols[] = {
221 US"smtp", /* HELO */
222 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
223 US"esmtp", /* EHLO */
224 US"esmtps", /* EHLO->STARTTLS->EHLO */
225 US"esmtpa", /* EHLO->AUTH */
226 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
227 };
228
229 #define pnormal 0
230 #define pextend 2
231 #define pcrpted 1 /* added to pextend or pnormal */
232 #define pauthed 2 /* added to pextend */
233
234 /* Sanity check and validate optional args to MAIL FROM: envelope */
235 enum {
236 ENV_MAIL_OPT_NULL,
237 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
238 #ifndef DISABLE_PRDR
239 ENV_MAIL_OPT_PRDR,
240 #endif
241 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
242 #ifdef SUPPORT_I18N
243 ENV_MAIL_OPT_UTF8,
244 #endif
245 };
246 typedef struct {
247 uschar * name; /* option requested during MAIL cmd */
248 int value; /* enum type */
249 BOOL need_value; /* TRUE requires value (name=value pair format)
250 FALSE is a singleton */
251 } env_mail_type_t;
252 static env_mail_type_t env_mail_type_list[] = {
253 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
254 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
255 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
256 #ifndef DISABLE_PRDR
257 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
258 #endif
259 { US"RET", ENV_MAIL_OPT_RET, TRUE },
260 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
261 #ifdef SUPPORT_I18N
262 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
263 #endif
264 /* keep this the last entry */
265 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
266 };
267
268 /* When reading SMTP from a remote host, we have to use our own versions of the
269 C input-reading functions, in order to be able to flush the SMTP output only
270 when about to read more data from the socket. This is the only way to get
271 optimal performance when the client is using pipelining. Flushing for every
272 command causes a separate packet and reply packet each time; saving all the
273 responses up (when pipelining) combines them into one packet and one response.
274
275 For simplicity, these functions are used for *all* SMTP input, not only when
276 receiving over a socket. However, after setting up a secure socket (SSL), input
277 is read via the OpenSSL library, and another set of functions is used instead
278 (see tls.c).
279
280 These functions are set in the receive_getc etc. variables and called with the
281 same interface as the C functions. However, since there can only ever be
282 one incoming SMTP call, we just use a single buffer and flags. There is no need
283 to implement a complicated private FILE-like structure.*/
284
285 static uschar *smtp_inbuffer;
286 static uschar *smtp_inptr;
287 static uschar *smtp_inend;
288 static int smtp_had_eof;
289 static int smtp_had_error;
290
291
292 /*************************************************
293 * SMTP version of getc() *
294 *************************************************/
295
296 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
297 it flushes the output, and refills the buffer, with a timeout. The signal
298 handler is set appropriately by the calling function. This function is not used
299 after a connection has negotated itself into an TLS/SSL state.
300
301 Arguments: none
302 Returns: the next character or EOF
303 */
304
305 int
306 smtp_getc(void)
307 {
308 if (smtp_inptr >= smtp_inend)
309 {
310 int rc, save_errno;
311 fflush(smtp_out);
312 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
313 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
314 save_errno = errno;
315 alarm(0);
316 if (rc <= 0)
317 {
318 /* Must put the error text in fixed store, because this might be during
319 header reading, where it releases unused store above the header. */
320 if (rc < 0)
321 {
322 smtp_had_error = save_errno;
323 smtp_read_error = string_copy_malloc(
324 string_sprintf(" (error: %s)", strerror(save_errno)));
325 }
326 else smtp_had_eof = 1;
327 return EOF;
328 }
329 #ifndef DISABLE_DKIM
330 dkim_exim_verify_feed(smtp_inbuffer, rc);
331 #endif
332 smtp_inend = smtp_inbuffer + rc;
333 smtp_inptr = smtp_inbuffer;
334 }
335 return *smtp_inptr++;
336 }
337
338
339
340 /*************************************************
341 * SMTP version of ungetc() *
342 *************************************************/
343
344 /* Puts a character back in the input buffer. Only ever
345 called once.
346
347 Arguments:
348 ch the character
349
350 Returns: the character
351 */
352
353 int
354 smtp_ungetc(int ch)
355 {
356 *(--smtp_inptr) = ch;
357 return ch;
358 }
359
360
361
362
363 /*************************************************
364 * SMTP version of feof() *
365 *************************************************/
366
367 /* Tests for a previous EOF
368
369 Arguments: none
370 Returns: non-zero if the eof flag is set
371 */
372
373 int
374 smtp_feof(void)
375 {
376 return smtp_had_eof;
377 }
378
379
380
381
382 /*************************************************
383 * SMTP version of ferror() *
384 *************************************************/
385
386 /* Tests for a previous read error, and returns with errno
387 restored to what it was when the error was detected.
388
389 Arguments: none
390 Returns: non-zero if the error flag is set
391 */
392
393 int
394 smtp_ferror(void)
395 {
396 errno = smtp_had_error;
397 return smtp_had_error;
398 }
399
400
401
402 /*************************************************
403 * Test for characters in the SMTP buffer *
404 *************************************************/
405
406 /* Used at the end of a message
407
408 Arguments: none
409 Returns: TRUE/FALSE
410 */
411
412 BOOL
413 smtp_buffered(void)
414 {
415 return smtp_inptr < smtp_inend;
416 }
417
418
419
420 /*************************************************
421 * Write formatted string to SMTP channel *
422 *************************************************/
423
424 /* This is a separate function so that we don't have to repeat everything for
425 TLS support or debugging. It is global so that the daemon and the
426 authentication functions can use it. It does not return any error indication,
427 because major problems such as dropped connections won't show up till an output
428 flush for non-TLS connections. The smtp_fflush() function is available for
429 checking that: for convenience, TLS output errors are remembered here so that
430 they are also picked up later by smtp_fflush().
431
432 Arguments:
433 format format string
434 ... optional arguments
435
436 Returns: nothing
437 */
438
439 void
440 smtp_printf(const char *format, ...)
441 {
442 va_list ap;
443
444 va_start(ap, format);
445 smtp_vprintf(format, ap);
446 va_end(ap);
447 }
448
449 /* This is split off so that verify.c:respond_printf() can, in effect, call
450 smtp_printf(), bearing in mind that in C a vararg function can't directly
451 call another vararg function, only a function which accepts a va_list. */
452
453 void
454 smtp_vprintf(const char *format, va_list ap)
455 {
456 BOOL yield;
457
458 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
459
460 DEBUG(D_receive)
461 {
462 void *reset_point = store_get(0);
463 uschar *msg_copy, *cr, *end;
464 msg_copy = string_copy(big_buffer);
465 end = msg_copy + Ustrlen(msg_copy);
466 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
467 memmove(cr, cr + 1, (end--) - cr);
468 debug_printf("SMTP>> %s", msg_copy);
469 store_reset(reset_point);
470 }
471
472 if (!yield)
473 {
474 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
475 smtp_closedown(US"Unexpected error");
476 exim_exit(EXIT_FAILURE);
477 }
478
479 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
480 have had the same. Note: this code is also present in smtp_respond(). It would
481 be tidier to have it only in one place, but when it was added, it was easier to
482 do it that way, so as not to have to mess with the code for the RCPT command,
483 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
484
485 if (rcpt_in_progress)
486 {
487 if (rcpt_smtp_response == NULL)
488 rcpt_smtp_response = string_copy(big_buffer);
489 else if (rcpt_smtp_response_same &&
490 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
491 rcpt_smtp_response_same = FALSE;
492 rcpt_in_progress = FALSE;
493 }
494
495 /* Now write the string */
496
497 #ifdef SUPPORT_TLS
498 if (tls_in.active >= 0)
499 {
500 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
501 smtp_write_error = -1;
502 }
503 else
504 #endif
505
506 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
507 }
508
509
510
511 /*************************************************
512 * Flush SMTP out and check for error *
513 *************************************************/
514
515 /* This function isn't currently used within Exim (it detects errors when it
516 tries to read the next SMTP input), but is available for use in local_scan().
517 For non-TLS connections, it flushes the output and checks for errors. For
518 TLS-connections, it checks for a previously-detected TLS write error.
519
520 Arguments: none
521 Returns: 0 for no error; -1 after an error
522 */
523
524 int
525 smtp_fflush(void)
526 {
527 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
528 return smtp_write_error;
529 }
530
531
532
533 /*************************************************
534 * SMTP command read timeout *
535 *************************************************/
536
537 /* Signal handler for timing out incoming SMTP commands. This attempts to
538 finish off tidily.
539
540 Argument: signal number (SIGALRM)
541 Returns: nothing
542 */
543
544 static void
545 command_timeout_handler(int sig)
546 {
547 sig = sig; /* Keep picky compilers happy */
548 log_write(L_lost_incoming_connection,
549 LOG_MAIN, "SMTP command timeout on%s connection from %s",
550 (tls_in.active >= 0)? " TLS" : "",
551 host_and_ident(FALSE));
552 if (smtp_batched_input)
553 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
554 smtp_notquit_exit(US"command-timeout", US"421",
555 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
556 exim_exit(EXIT_FAILURE);
557 }
558
559
560
561 /*************************************************
562 * SIGTERM received *
563 *************************************************/
564
565 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
566
567 Argument: signal number (SIGTERM)
568 Returns: nothing
569 */
570
571 static void
572 command_sigterm_handler(int sig)
573 {
574 sig = sig; /* Keep picky compilers happy */
575 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
576 if (smtp_batched_input)
577 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
578 smtp_notquit_exit(US"signal-exit", US"421",
579 US"%s: Service not available - closing connection", smtp_active_hostname);
580 exim_exit(EXIT_FAILURE);
581 }
582
583
584
585
586 #ifdef SUPPORT_PROXY
587 /*************************************************
588 * Restore socket timeout to previous value *
589 *************************************************/
590 /* If the previous value was successfully retrieved, restore
591 it before returning control to the non-proxy routines
592
593 Arguments: fd - File descriptor for input
594 get_ok - Successfully retrieved previous values
595 tvtmp - Time struct with previous values
596 vslen - Length of time struct
597 Returns: none
598 */
599 static void
600 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
601 {
602 if (get_ok == 0)
603 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
604 }
605
606 /*************************************************
607 * Check if host is required proxy host *
608 *************************************************/
609 /* The function determines if inbound host will be a regular smtp host
610 or if it is configured that it must use Proxy Protocol.
611
612 Arguments: none
613 Returns: bool
614 */
615
616 static BOOL
617 check_proxy_protocol_host()
618 {
619 int rc;
620 /* Cannot configure local connection as a proxy inbound */
621 if (sender_host_address == NULL) return proxy_session;
622
623 rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
624 sender_host_address, NULL);
625 if (rc == OK)
626 {
627 DEBUG(D_receive)
628 debug_printf("Detected proxy protocol configured host\n");
629 proxy_session = TRUE;
630 }
631 return proxy_session;
632 }
633
634
635 /*************************************************
636 * Setup host for proxy protocol *
637 *************************************************/
638 /* The function configures the connection based on a header from the
639 inbound host to use Proxy Protocol. The specification is very exact
640 so exit with an error if do not find the exact required pieces. This
641 includes an incorrect number of spaces separating args.
642
643 Arguments: none
644 Returns: int
645 */
646
647 static BOOL
648 setup_proxy_protocol_host()
649 {
650 union {
651 struct {
652 uschar line[108];
653 } v1;
654 struct {
655 uschar sig[12];
656 uint8_t ver_cmd;
657 uint8_t fam;
658 uint16_t len;
659 union {
660 struct { /* TCP/UDP over IPv4, len = 12 */
661 uint32_t src_addr;
662 uint32_t dst_addr;
663 uint16_t src_port;
664 uint16_t dst_port;
665 } ip4;
666 struct { /* TCP/UDP over IPv6, len = 36 */
667 uint8_t src_addr[16];
668 uint8_t dst_addr[16];
669 uint16_t src_port;
670 uint16_t dst_port;
671 } ip6;
672 struct { /* AF_UNIX sockets, len = 216 */
673 uschar src_addr[108];
674 uschar dst_addr[108];
675 } unx;
676 } addr;
677 } v2;
678 } hdr;
679
680 /* Temp variables used in PPv2 address:port parsing */
681 uint16_t tmpport;
682 char tmpip[INET_ADDRSTRLEN];
683 struct sockaddr_in tmpaddr;
684 char tmpip6[INET6_ADDRSTRLEN];
685 struct sockaddr_in6 tmpaddr6;
686
687 int get_ok = 0;
688 int size, ret, fd;
689 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
690 uschar *iptype; /* To display debug info */
691 struct timeval tv;
692 socklen_t vslen = 0;
693 struct timeval tvtmp;
694
695 vslen = sizeof(struct timeval);
696
697 fd = fileno(smtp_in);
698
699 /* Save current socket timeout values */
700 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
701 &vslen);
702
703 /* Proxy Protocol host must send header within a short time
704 (default 3 seconds) or it's considered invalid */
705 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
706 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
707 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
708 sizeof(struct timeval));
709
710 do
711 {
712 /* The inbound host was declared to be a Proxy Protocol host, so
713 don't do a PEEK into the data, actually slurp it up. */
714 ret = recv(fd, &hdr, sizeof(hdr), 0);
715 }
716 while (ret == -1 && errno == EINTR);
717
718 if (ret == -1)
719 {
720 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
721 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
722 }
723
724 if (ret >= 16 &&
725 memcmp(&hdr.v2, v2sig, 12) == 0)
726 {
727 uint8_t ver, cmd;
728
729 /* May 2014: haproxy combined the version and command into one byte to
730 allow two full bytes for the length field in order to proxy SSL
731 connections. SSL Proxy is not supported in this version of Exim, but
732 must still seperate values here. */
733 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
734 cmd = (hdr.v2.ver_cmd & 0x0f);
735
736 if (ver != 0x02)
737 {
738 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
739 goto proxyfail;
740 }
741 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
742 /* The v2 header will always be 16 bytes per the spec. */
743 size = 16 + hdr.v2.len;
744 if (ret < size)
745 {
746 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
747 ret, size);
748 goto proxyfail;
749 }
750 switch (cmd)
751 {
752 case 0x01: /* PROXY command */
753 switch (hdr.v2.fam)
754 {
755 case 0x11: /* TCPv4 address type */
756 iptype = US"IPv4";
757 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
758 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
759 if (!string_is_ip_address(US tmpip,NULL))
760 {
761 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
762 return ERRNO_PROXYFAIL;
763 }
764 proxy_local_address = sender_host_address;
765 sender_host_address = string_copy(US tmpip);
766 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
767 proxy_local_port = sender_host_port;
768 sender_host_port = tmpport;
769 /* Save dest ip/port */
770 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
771 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
772 if (!string_is_ip_address(US tmpip,NULL))
773 {
774 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
775 return ERRNO_PROXYFAIL;
776 }
777 proxy_external_address = string_copy(US tmpip);
778 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
779 proxy_external_port = tmpport;
780 goto done;
781 case 0x21: /* TCPv6 address type */
782 iptype = US"IPv6";
783 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
784 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
785 if (!string_is_ip_address(US tmpip6,NULL))
786 {
787 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
788 return ERRNO_PROXYFAIL;
789 }
790 proxy_local_address = sender_host_address;
791 sender_host_address = string_copy(US tmpip6);
792 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
793 proxy_local_port = sender_host_port;
794 sender_host_port = tmpport;
795 /* Save dest ip/port */
796 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
797 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
798 if (!string_is_ip_address(US tmpip6,NULL))
799 {
800 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
801 return ERRNO_PROXYFAIL;
802 }
803 proxy_external_address = string_copy(US tmpip6);
804 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
805 proxy_external_port = tmpport;
806 goto done;
807 default:
808 DEBUG(D_receive)
809 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
810 hdr.v2.fam);
811 goto proxyfail;
812 }
813 /* Unsupported protocol, keep local connection address */
814 break;
815 case 0x00: /* LOCAL command */
816 /* Keep local connection address for LOCAL */
817 break;
818 default:
819 DEBUG(D_receive)
820 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
821 goto proxyfail;
822 }
823 }
824 else if (ret >= 8 &&
825 memcmp(hdr.v1.line, "PROXY", 5) == 0)
826 {
827 uschar *p = string_copy(hdr.v1.line);
828 uschar *end = memchr(p, '\r', ret - 1);
829 uschar *sp; /* Utility variables follow */
830 int tmp_port;
831 char *endc;
832
833 if (!end || end[1] != '\n')
834 {
835 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
836 goto proxyfail;
837 }
838 *end = '\0'; /* Terminate the string */
839 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
840 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
841 /* Step through the string looking for the required fields. Ensure
842 strict adherance to required formatting, exit for any error. */
843 p += 5;
844 if (!isspace(*(p++)))
845 {
846 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
847 goto proxyfail;
848 }
849 if (!Ustrncmp(p, CCS"TCP4", 4))
850 iptype = US"IPv4";
851 else if (!Ustrncmp(p,CCS"TCP6", 4))
852 iptype = US"IPv6";
853 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
854 {
855 iptype = US"Unknown";
856 goto done;
857 }
858 else
859 {
860 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
861 goto proxyfail;
862 }
863
864 p += Ustrlen(iptype);
865 if (!isspace(*(p++)))
866 {
867 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
868 goto proxyfail;
869 }
870 /* Find the end of the arg */
871 if ((sp = Ustrchr(p, ' ')) == NULL)
872 {
873 DEBUG(D_receive)
874 debug_printf("Did not find proxied src %s\n", iptype);
875 goto proxyfail;
876 }
877 *sp = '\0';
878 if(!string_is_ip_address(p,NULL))
879 {
880 DEBUG(D_receive)
881 debug_printf("Proxied src arg is not an %s address\n", iptype);
882 goto proxyfail;
883 }
884 proxy_local_address = sender_host_address;
885 sender_host_address = p;
886 p = sp + 1;
887 if ((sp = Ustrchr(p, ' ')) == NULL)
888 {
889 DEBUG(D_receive)
890 debug_printf("Did not find proxy dest %s\n", iptype);
891 goto proxyfail;
892 }
893 *sp = '\0';
894 if(!string_is_ip_address(p,NULL))
895 {
896 DEBUG(D_receive)
897 debug_printf("Proxy dest arg is not an %s address\n", iptype);
898 goto proxyfail;
899 }
900 proxy_external_address = p;
901 p = sp + 1;
902 if ((sp = Ustrchr(p, ' ')) == NULL)
903 {
904 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
905 goto proxyfail;
906 }
907 *sp = '\0';
908 tmp_port = strtol(CCS p,&endc,10);
909 if (*endc || tmp_port == 0)
910 {
911 DEBUG(D_receive)
912 debug_printf("Proxied src port '%s' not an integer\n", p);
913 goto proxyfail;
914 }
915 proxy_local_port = sender_host_port;
916 sender_host_port = tmp_port;
917 p = sp + 1;
918 if ((sp = Ustrchr(p, '\0')) == NULL)
919 {
920 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
921 goto proxyfail;
922 }
923 tmp_port = strtol(CCS p,&endc,10);
924 if (*endc || tmp_port == 0)
925 {
926 DEBUG(D_receive)
927 debug_printf("Proxy dest port '%s' not an integer\n", p);
928 goto proxyfail;
929 }
930 proxy_external_port = tmp_port;
931 /* Already checked for /r /n above. Good V1 header received. */
932 goto done;
933 }
934 else
935 {
936 /* Wrong protocol */
937 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
938 goto proxyfail;
939 }
940
941 proxyfail:
942 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
943 /* Don't flush any potential buffer contents. Any input should cause a
944 synchronization failure */
945 return FALSE;
946
947 done:
948 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
949 DEBUG(D_receive)
950 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
951 return proxy_session;
952 }
953 #endif
954
955 /*************************************************
956 * Read one command line *
957 *************************************************/
958
959 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
960 There are sites that don't do this, and in any case internal SMTP probably
961 should check only for LF. Consequently, we check here for LF only. The line
962 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
963 an unknown command. The command is read into the global smtp_cmd_buffer so that
964 it is available via $smtp_command.
965
966 The character reading routine sets up a timeout for each block actually read
967 from the input (which may contain more than one command). We set up a special
968 signal handler that closes down the session on a timeout. Control does not
969 return when it runs.
970
971 Arguments:
972 check_sync if TRUE, check synchronization rules if global option is TRUE
973
974 Returns: a code identifying the command (enumerated above)
975 */
976
977 static int
978 smtp_read_command(BOOL check_sync)
979 {
980 int c;
981 int ptr = 0;
982 smtp_cmd_list *p;
983 BOOL hadnull = FALSE;
984
985 os_non_restarting_signal(SIGALRM, command_timeout_handler);
986
987 while ((c = (receive_getc)()) != '\n' && c != EOF)
988 {
989 if (ptr >= smtp_cmd_buffer_size)
990 {
991 os_non_restarting_signal(SIGALRM, sigalrm_handler);
992 return OTHER_CMD;
993 }
994 if (c == 0)
995 {
996 hadnull = TRUE;
997 c = '?';
998 }
999 smtp_cmd_buffer[ptr++] = c;
1000 }
1001
1002 receive_linecount++; /* For BSMTP errors */
1003 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1004
1005 /* If hit end of file, return pseudo EOF command. Whether we have a
1006 part-line already read doesn't matter, since this is an error state. */
1007
1008 if (c == EOF) return EOF_CMD;
1009
1010 /* Remove any CR and white space at the end of the line, and terminate the
1011 string. */
1012
1013 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1014 smtp_cmd_buffer[ptr] = 0;
1015
1016 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1017
1018 /* NULLs are not allowed in SMTP commands */
1019
1020 if (hadnull) return BADCHAR_CMD;
1021
1022 /* Scan command list and return identity, having set the data pointer
1023 to the start of the actual data characters. Check for SMTP synchronization
1024 if required. */
1025
1026 for (p = cmd_list; p < cmd_list_end; p++)
1027 {
1028 #ifdef SUPPORT_PROXY
1029 /* Only allow QUIT command if Proxy Protocol parsing failed */
1030 if (proxy_session && proxy_session_failed)
1031 {
1032 if (p->cmd != QUIT_CMD)
1033 continue;
1034 }
1035 #endif
1036 if ( p->len
1037 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1038 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1039 || smtp_cmd_buffer[p->len] == 0
1040 || smtp_cmd_buffer[p->len] == ' '
1041 ) )
1042 {
1043 if (smtp_inptr < smtp_inend && /* Outstanding input */
1044 p->cmd < sync_cmd_limit && /* Command should sync */
1045 check_sync && /* Local flag set */
1046 smtp_enforce_sync && /* Global flag set */
1047 sender_host_address != NULL && /* Not local input */
1048 !sender_host_notsocket) /* Really is a socket */
1049 return BADSYN_CMD;
1050
1051 /* The variables $smtp_command and $smtp_command_argument point into the
1052 unmodified input buffer. A copy of the latter is taken for actual
1053 processing, so that it can be chopped up into separate parts if necessary,
1054 for example, when processing a MAIL command options such as SIZE that can
1055 follow the sender address. */
1056
1057 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1058 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1059 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1060 smtp_cmd_data = smtp_data_buffer;
1061
1062 /* Count non-mail commands from those hosts that are controlled in this
1063 way. The default is all hosts. We don't waste effort checking the list
1064 until we get a non-mail command, but then cache the result to save checking
1065 again. If there's a DEFER while checking the host, assume it's in the list.
1066
1067 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1068 start of each incoming message by fiddling with the value in the table. */
1069
1070 if (!p->is_mail_cmd)
1071 {
1072 if (count_nonmail == TRUE_UNSET) count_nonmail =
1073 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1074 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1075 return TOO_MANY_NONMAIL_CMD;
1076 }
1077
1078 /* If there is data for a command that does not expect it, generate the
1079 error here. */
1080
1081 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1082 }
1083 }
1084
1085 #ifdef SUPPORT_PROXY
1086 /* Only allow QUIT command if Proxy Protocol parsing failed */
1087 if (proxy_session && proxy_session_failed)
1088 return PROXY_FAIL_IGNORE_CMD;
1089 #endif
1090
1091 /* Enforce synchronization for unknown commands */
1092
1093 if (smtp_inptr < smtp_inend && /* Outstanding input */
1094 check_sync && /* Local flag set */
1095 smtp_enforce_sync && /* Global flag set */
1096 sender_host_address != NULL && /* Not local input */
1097 !sender_host_notsocket) /* Really is a socket */
1098 return BADSYN_CMD;
1099
1100 return OTHER_CMD;
1101 }
1102
1103
1104
1105 /*************************************************
1106 * Recheck synchronization *
1107 *************************************************/
1108
1109 /* Synchronization checks can never be perfect because a packet may be on its
1110 way but not arrived when the check is done. Such checks can in any case only be
1111 done when TLS is not in use. Normally, the checks happen when commands are
1112 read: Exim ensures that there is no more input in the input buffer. In normal
1113 cases, the response to the command will be fast, and there is no further check.
1114
1115 However, for some commands an ACL is run, and that can include delays. In those
1116 cases, it is useful to do another check on the input just before sending the
1117 response. This also applies at the start of a connection. This function does
1118 that check by means of the select() function, as long as the facility is not
1119 disabled or inappropriate. A failure of select() is ignored.
1120
1121 When there is unwanted input, we read it so that it appears in the log of the
1122 error.
1123
1124 Arguments: none
1125 Returns: TRUE if all is well; FALSE if there is input pending
1126 */
1127
1128 static BOOL
1129 check_sync(void)
1130 {
1131 int fd, rc;
1132 fd_set fds;
1133 struct timeval tzero;
1134
1135 if (!smtp_enforce_sync || sender_host_address == NULL ||
1136 sender_host_notsocket || tls_in.active >= 0)
1137 return TRUE;
1138
1139 fd = fileno(smtp_in);
1140 FD_ZERO(&fds);
1141 FD_SET(fd, &fds);
1142 tzero.tv_sec = 0;
1143 tzero.tv_usec = 0;
1144 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1145
1146 if (rc <= 0) return TRUE; /* Not ready to read */
1147 rc = smtp_getc();
1148 if (rc < 0) return TRUE; /* End of file or error */
1149
1150 smtp_ungetc(rc);
1151 rc = smtp_inend - smtp_inptr;
1152 if (rc > 150) rc = 150;
1153 smtp_inptr[rc] = 0;
1154 return FALSE;
1155 }
1156
1157
1158
1159 /*************************************************
1160 * Forced closedown of call *
1161 *************************************************/
1162
1163 /* This function is called from log.c when Exim is dying because of a serious
1164 disaster, and also from some other places. If an incoming non-batched SMTP
1165 channel is open, it swallows the rest of the incoming message if in the DATA
1166 phase, sends the reply string, and gives an error to all subsequent commands
1167 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1168 smtp_in.
1169
1170 Arguments:
1171 message SMTP reply string to send, excluding the code
1172
1173 Returns: nothing
1174 */
1175
1176 void
1177 smtp_closedown(uschar *message)
1178 {
1179 if (smtp_in == NULL || smtp_batched_input) return;
1180 receive_swallow_smtp();
1181 smtp_printf("421 %s\r\n", message);
1182
1183 for (;;)
1184 {
1185 switch(smtp_read_command(FALSE))
1186 {
1187 case EOF_CMD:
1188 return;
1189
1190 case QUIT_CMD:
1191 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1192 mac_smtp_fflush();
1193 return;
1194
1195 case RSET_CMD:
1196 smtp_printf("250 Reset OK\r\n");
1197 break;
1198
1199 default:
1200 smtp_printf("421 %s\r\n", message);
1201 break;
1202 }
1203 }
1204 }
1205
1206
1207
1208
1209 /*************************************************
1210 * Set up connection info for logging *
1211 *************************************************/
1212
1213 /* This function is called when logging information about an SMTP connection.
1214 It sets up appropriate source information, depending on the type of connection.
1215 If sender_fullhost is NULL, we are at a very early stage of the connection;
1216 just use the IP address.
1217
1218 Argument: none
1219 Returns: a string describing the connection
1220 */
1221
1222 uschar *
1223 smtp_get_connection_info(void)
1224 {
1225 uschar *hostname = (sender_fullhost == NULL)?
1226 sender_host_address : sender_fullhost;
1227
1228 if (host_checking)
1229 return string_sprintf("SMTP connection from %s", hostname);
1230
1231 if (sender_host_unknown || sender_host_notsocket)
1232 return string_sprintf("SMTP connection from %s", sender_ident);
1233
1234 if (is_inetd)
1235 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1236
1237 if (LOGGING(incoming_interface) && interface_address != NULL)
1238 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1239 interface_address, interface_port);
1240
1241 return string_sprintf("SMTP connection from %s", hostname);
1242 }
1243
1244
1245
1246 #ifdef SUPPORT_TLS
1247 /* Append TLS-related information to a log line
1248
1249 Arguments:
1250 s String under construction: allocated string to extend, or NULL
1251 sizep Pointer to current allocation size (update on return), or NULL
1252 ptrp Pointer to index for new entries in string (update on return), or NULL
1253
1254 Returns: Allocated string or NULL
1255 */
1256 static uschar *
1257 s_tlslog(uschar * s, int * sizep, int * ptrp)
1258 {
1259 int size = sizep ? *sizep : 0;
1260 int ptr = ptrp ? *ptrp : 0;
1261
1262 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1263 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1264 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1265 s = string_append(s, &size, &ptr, 2, US" CV=",
1266 tls_in.certificate_verified? "yes":"no");
1267 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1268 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1269 string_printing(tls_in.peerdn), US"\"");
1270 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1271 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1272 string_printing(tls_in.sni), US"\"");
1273
1274 if (s)
1275 {
1276 s[ptr] = '\0';
1277 if (sizep) *sizep = size;
1278 if (ptrp) *ptrp = ptr;
1279 }
1280 return s;
1281 }
1282 #endif
1283
1284 /*************************************************
1285 * Log lack of MAIL if so configured *
1286 *************************************************/
1287
1288 /* This function is called when an SMTP session ends. If the log selector
1289 smtp_no_mail is set, write a log line giving some details of what has happened
1290 in the SMTP session.
1291
1292 Arguments: none
1293 Returns: nothing
1294 */
1295
1296 void
1297 smtp_log_no_mail(void)
1298 {
1299 int size, ptr, i;
1300 uschar *s, *sep;
1301
1302 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1303 return;
1304
1305 s = NULL;
1306 size = ptr = 0;
1307
1308 if (sender_host_authenticated != NULL)
1309 {
1310 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1311 if (authenticated_id != NULL)
1312 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1313 }
1314
1315 #ifdef SUPPORT_TLS
1316 s = s_tlslog(s, &size, &ptr);
1317 #endif
1318
1319 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1320 US" C=..." : US" C=";
1321 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1322 {
1323 if (smtp_connection_had[i] != SCH_NONE)
1324 {
1325 s = string_append(s, &size, &ptr, 2, sep,
1326 smtp_names[smtp_connection_had[i]]);
1327 sep = US",";
1328 }
1329 }
1330
1331 for (i = 0; i < smtp_ch_index; i++)
1332 {
1333 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1334 sep = US",";
1335 }
1336
1337 if (s != NULL) s[ptr] = 0; else s = US"";
1338 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1339 host_and_ident(FALSE),
1340 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1341 s);
1342 }
1343
1344
1345
1346 /*************************************************
1347 * Check HELO line and set sender_helo_name *
1348 *************************************************/
1349
1350 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1351 the domain name of the sending host, or an ip literal in square brackets. The
1352 arrgument is placed in sender_helo_name, which is in malloc store, because it
1353 must persist over multiple incoming messages. If helo_accept_junk is set, this
1354 host is permitted to send any old junk (needed for some broken hosts).
1355 Otherwise, helo_allow_chars can be used for rogue characters in general
1356 (typically people want to let in underscores).
1357
1358 Argument:
1359 s the data portion of the line (already past any white space)
1360
1361 Returns: TRUE or FALSE
1362 */
1363
1364 static BOOL
1365 check_helo(uschar *s)
1366 {
1367 uschar *start = s;
1368 uschar *end = s + Ustrlen(s);
1369 BOOL yield = helo_accept_junk;
1370
1371 /* Discard any previous helo name */
1372
1373 if (sender_helo_name != NULL)
1374 {
1375 store_free(sender_helo_name);
1376 sender_helo_name = NULL;
1377 }
1378
1379 /* Skip tests if junk is permitted. */
1380
1381 if (!yield)
1382 {
1383 /* Allow the new standard form for IPv6 address literals, namely,
1384 [IPv6:....], and because someone is bound to use it, allow an equivalent
1385 IPv4 form. Allow plain addresses as well. */
1386
1387 if (*s == '[')
1388 {
1389 if (end[-1] == ']')
1390 {
1391 end[-1] = 0;
1392 if (strncmpic(s, US"[IPv6:", 6) == 0)
1393 yield = (string_is_ip_address(s+6, NULL) == 6);
1394 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1395 yield = (string_is_ip_address(s+6, NULL) == 4);
1396 else
1397 yield = (string_is_ip_address(s+1, NULL) != 0);
1398 end[-1] = ']';
1399 }
1400 }
1401
1402 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1403 that have been configured (usually underscore - sigh). */
1404
1405 else if (*s != 0)
1406 {
1407 yield = TRUE;
1408 while (*s != 0)
1409 {
1410 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1411 Ustrchr(helo_allow_chars, *s) == NULL)
1412 {
1413 yield = FALSE;
1414 break;
1415 }
1416 s++;
1417 }
1418 }
1419 }
1420
1421 /* Save argument if OK */
1422
1423 if (yield) sender_helo_name = string_copy_malloc(start);
1424 return yield;
1425 }
1426
1427
1428
1429
1430
1431 /*************************************************
1432 * Extract SMTP command option *
1433 *************************************************/
1434
1435 /* This function picks the next option setting off the end of smtp_cmd_data. It
1436 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1437 things that can appear there.
1438
1439 Arguments:
1440 name point this at the name
1441 value point this at the data string
1442
1443 Returns: TRUE if found an option
1444 */
1445
1446 static BOOL
1447 extract_option(uschar **name, uschar **value)
1448 {
1449 uschar *n;
1450 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1451 while (isspace(*v)) v--;
1452 v[1] = 0;
1453 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1454
1455 n = v;
1456 if (*v == '=')
1457 {
1458 while(isalpha(n[-1])) n--;
1459 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1460 if (!isspace(n[-1])) return FALSE;
1461 n[-1] = 0;
1462 }
1463 else
1464 {
1465 n++;
1466 if (v == smtp_cmd_data) return FALSE;
1467 }
1468 *v++ = 0;
1469 *name = n;
1470 *value = v;
1471 return TRUE;
1472 }
1473
1474
1475
1476
1477
1478 /*************************************************
1479 * Reset for new message *
1480 *************************************************/
1481
1482 /* This function is called whenever the SMTP session is reset from
1483 within either of the setup functions.
1484
1485 Argument: the stacking pool storage reset point
1486 Returns: nothing
1487 */
1488
1489 static void
1490 smtp_reset(void *reset_point)
1491 {
1492 store_reset(reset_point);
1493 recipients_list = NULL;
1494 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1495 raw_recipients_count = recipients_count = recipients_list_max = 0;
1496 cancel_cutthrough_connection("smtp reset");
1497 message_linecount = 0;
1498 message_size = -1;
1499 acl_added_headers = NULL;
1500 acl_removed_headers = NULL;
1501 queue_only_policy = FALSE;
1502 rcpt_smtp_response = NULL;
1503 rcpt_smtp_response_same = TRUE;
1504 rcpt_in_progress = FALSE;
1505 deliver_freeze = FALSE; /* Can be set by ACL */
1506 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1507 fake_response = OK; /* Can be set by ACL */
1508 #ifdef WITH_CONTENT_SCAN
1509 no_mbox_unspool = FALSE; /* Can be set by ACL */
1510 #endif
1511 submission_mode = FALSE; /* Can be set by ACL */
1512 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1513 active_local_from_check = local_from_check; /* Can be set by ACL */
1514 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1515 sender_address = NULL;
1516 submission_name = NULL; /* Can be set by ACL */
1517 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1518 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1519 sender_verified_list = NULL; /* No senders verified */
1520 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1521 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1522
1523 #ifndef DISABLE_PRDR
1524 prdr_requested = FALSE;
1525 #endif
1526
1527 /* Reset the DSN flags */
1528 dsn_ret = 0;
1529 dsn_envid = NULL;
1530
1531 authenticated_sender = NULL;
1532 #ifdef EXPERIMENTAL_BRIGHTMAIL
1533 bmi_run = 0;
1534 bmi_verdicts = NULL;
1535 #endif
1536 #ifndef DISABLE_DKIM
1537 dkim_signers = NULL;
1538 dkim_disable_verify = FALSE;
1539 dkim_collect_input = FALSE;
1540 #endif
1541 #ifdef EXPERIMENTAL_SPF
1542 spf_header_comment = NULL;
1543 spf_received = NULL;
1544 spf_result = NULL;
1545 spf_smtp_comment = NULL;
1546 #endif
1547 #ifdef SUPPORT_I18N
1548 message_smtputf8 = FALSE;
1549 #endif
1550 body_linecount = body_zerocount = 0;
1551
1552 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1553 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1554 /* Note that ratelimiters_conn persists across resets. */
1555
1556 /* Reset message ACL variables */
1557
1558 acl_var_m = NULL;
1559
1560 /* The message body variables use malloc store. They may be set if this is
1561 not the first message in an SMTP session and the previous message caused them
1562 to be referenced in an ACL. */
1563
1564 if (message_body != NULL)
1565 {
1566 store_free(message_body);
1567 message_body = NULL;
1568 }
1569
1570 if (message_body_end != NULL)
1571 {
1572 store_free(message_body_end);
1573 message_body_end = NULL;
1574 }
1575
1576 /* Warning log messages are also saved in malloc store. They are saved to avoid
1577 repetition in the same message, but it seems right to repeat them for different
1578 messages. */
1579
1580 while (acl_warn_logged != NULL)
1581 {
1582 string_item *this = acl_warn_logged;
1583 acl_warn_logged = acl_warn_logged->next;
1584 store_free(this);
1585 }
1586 }
1587
1588
1589
1590
1591
1592 /*************************************************
1593 * Initialize for incoming batched SMTP message *
1594 *************************************************/
1595
1596 /* This function is called from smtp_setup_msg() in the case when
1597 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1598 of messages in one file with SMTP commands between them. All errors must be
1599 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1600 relevant. After an error on a sender, or an invalid recipient, the remainder
1601 of the message is skipped. The value of received_protocol is already set.
1602
1603 Argument: none
1604 Returns: > 0 message successfully started (reached DATA)
1605 = 0 QUIT read or end of file reached
1606 < 0 should not occur
1607 */
1608
1609 static int
1610 smtp_setup_batch_msg(void)
1611 {
1612 int done = 0;
1613 void *reset_point = store_get(0);
1614
1615 /* Save the line count at the start of each transaction - single commands
1616 like HELO and RSET count as whole transactions. */
1617
1618 bsmtp_transaction_linecount = receive_linecount;
1619
1620 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1621
1622 smtp_reset(reset_point); /* Reset for start of message */
1623
1624 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1625 value. The values are 2 larger than the required yield of the function. */
1626
1627 while (done <= 0)
1628 {
1629 uschar *errmess;
1630 uschar *recipient = NULL;
1631 int start, end, sender_domain, recipient_domain;
1632
1633 switch(smtp_read_command(FALSE))
1634 {
1635 /* The HELO/EHLO commands set sender_address_helo if they have
1636 valid data; otherwise they are ignored, except that they do
1637 a reset of the state. */
1638
1639 case HELO_CMD:
1640 case EHLO_CMD:
1641
1642 check_helo(smtp_cmd_data);
1643 /* Fall through */
1644
1645 case RSET_CMD:
1646 smtp_reset(reset_point);
1647 bsmtp_transaction_linecount = receive_linecount;
1648 break;
1649
1650
1651 /* The MAIL FROM command requires an address as an operand. All we
1652 do here is to parse it for syntactic correctness. The form "<>" is
1653 a special case which converts into an empty string. The start/end
1654 pointers in the original are not used further for this address, as
1655 it is the canonical extracted address which is all that is kept. */
1656
1657 case MAIL_CMD:
1658 smtp_mailcmd_count++; /* Count for no-mail log */
1659 if (sender_address != NULL)
1660 /* The function moan_smtp_batch() does not return. */
1661 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1662
1663 if (smtp_cmd_data[0] == 0)
1664 /* The function moan_smtp_batch() does not return. */
1665 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1666
1667 /* Reset to start of message */
1668
1669 smtp_reset(reset_point);
1670
1671 /* Apply SMTP rewrite */
1672
1673 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1674 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1675 US"", global_rewrite_rules) : smtp_cmd_data;
1676
1677 /* Extract the address; the TRUE flag allows <> as valid */
1678
1679 raw_sender =
1680 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1681 TRUE);
1682
1683 if (raw_sender == NULL)
1684 /* The function moan_smtp_batch() does not return. */
1685 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1686
1687 sender_address = string_copy(raw_sender);
1688
1689 /* Qualify unqualified sender addresses if permitted to do so. */
1690
1691 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1692 {
1693 if (allow_unqualified_sender)
1694 {
1695 sender_address = rewrite_address_qualify(sender_address, FALSE);
1696 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1697 "and rewritten\n", raw_sender);
1698 }
1699 /* The function moan_smtp_batch() does not return. */
1700 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1701 "a domain");
1702 }
1703 break;
1704
1705
1706 /* The RCPT TO command requires an address as an operand. All we do
1707 here is to parse it for syntactic correctness. There may be any number
1708 of RCPT TO commands, specifying multiple senders. We build them all into
1709 a data structure that is in argc/argv format. The start/end values
1710 given by parse_extract_address are not used, as we keep only the
1711 extracted address. */
1712
1713 case RCPT_CMD:
1714 if (sender_address == NULL)
1715 /* The function moan_smtp_batch() does not return. */
1716 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1717
1718 if (smtp_cmd_data[0] == 0)
1719 /* The function moan_smtp_batch() does not return. */
1720 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1721
1722 /* Check maximum number allowed */
1723
1724 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1725 /* The function moan_smtp_batch() does not return. */
1726 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1727 recipients_max_reject? "552": "452");
1728
1729 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1730 recipient address */
1731
1732 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1733 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1734 global_rewrite_rules) : smtp_cmd_data;
1735
1736 /* rfc821_domains = TRUE; << no longer needed */
1737 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1738 &recipient_domain, FALSE);
1739 /* rfc821_domains = FALSE; << no longer needed */
1740
1741 if (recipient == NULL)
1742 /* The function moan_smtp_batch() does not return. */
1743 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1744
1745 /* If the recipient address is unqualified, qualify it if permitted. Then
1746 add it to the list of recipients. */
1747
1748 if (recipient_domain == 0)
1749 {
1750 if (allow_unqualified_recipient)
1751 {
1752 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1753 recipient);
1754 recipient = rewrite_address_qualify(recipient, TRUE);
1755 }
1756 /* The function moan_smtp_batch() does not return. */
1757 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1758 "a domain");
1759 }
1760 receive_add_recipient(recipient, -1);
1761 break;
1762
1763
1764 /* The DATA command is legal only if it follows successful MAIL FROM
1765 and RCPT TO commands. This function is complete when a valid DATA
1766 command is encountered. */
1767
1768 case DATA_CMD:
1769 if (sender_address == NULL || recipients_count <= 0)
1770 {
1771 /* The function moan_smtp_batch() does not return. */
1772 if (sender_address == NULL)
1773 moan_smtp_batch(smtp_cmd_buffer,
1774 "503 MAIL FROM:<sender> command must precede DATA");
1775 else
1776 moan_smtp_batch(smtp_cmd_buffer,
1777 "503 RCPT TO:<recipient> must precede DATA");
1778 }
1779 else
1780 {
1781 done = 3; /* DATA successfully achieved */
1782 message_ended = END_NOTENDED; /* Indicate in middle of message */
1783 }
1784 break;
1785
1786
1787 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1788
1789 case VRFY_CMD:
1790 case EXPN_CMD:
1791 case HELP_CMD:
1792 case NOOP_CMD:
1793 case ETRN_CMD:
1794 bsmtp_transaction_linecount = receive_linecount;
1795 break;
1796
1797
1798 case EOF_CMD:
1799 case QUIT_CMD:
1800 done = 2;
1801 break;
1802
1803
1804 case BADARG_CMD:
1805 /* The function moan_smtp_batch() does not return. */
1806 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1807 break;
1808
1809
1810 case BADCHAR_CMD:
1811 /* The function moan_smtp_batch() does not return. */
1812 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1813 break;
1814
1815
1816 default:
1817 /* The function moan_smtp_batch() does not return. */
1818 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1819 break;
1820 }
1821 }
1822
1823 return done - 2; /* Convert yield values */
1824 }
1825
1826
1827
1828
1829 /*************************************************
1830 * Start an SMTP session *
1831 *************************************************/
1832
1833 /* This function is called at the start of an SMTP session. Thereafter,
1834 smtp_setup_msg() is called to initiate each separate message. This
1835 function does host-specific testing, and outputs the banner line.
1836
1837 Arguments: none
1838 Returns: FALSE if the session can not continue; something has
1839 gone wrong, or the connection to the host is blocked
1840 */
1841
1842 BOOL
1843 smtp_start_session(void)
1844 {
1845 int size = 256;
1846 int ptr, esclen;
1847 uschar *user_msg, *log_msg;
1848 uschar *code, *esc;
1849 uschar *p, *s, *ss;
1850
1851 smtp_connection_start = time(NULL);
1852 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1853 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1854 smtp_ch_index = 0;
1855
1856 /* Default values for certain variables */
1857
1858 helo_seen = esmtp = helo_accept_junk = FALSE;
1859 smtp_mailcmd_count = 0;
1860 count_nonmail = TRUE_UNSET;
1861 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1862 smtp_delay_mail = smtp_rlm_base;
1863 auth_advertised = FALSE;
1864 pipelining_advertised = FALSE;
1865 pipelining_enable = TRUE;
1866 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1867 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1868
1869 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1870 authentication settings from -oMaa to remain in force. */
1871
1872 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1873 authenticated_by = NULL;
1874
1875 #ifdef SUPPORT_TLS
1876 tls_in.cipher = tls_in.peerdn = NULL;
1877 tls_in.ourcert = tls_in.peercert = NULL;
1878 tls_in.sni = NULL;
1879 tls_in.ocsp = OCSP_NOT_REQ;
1880 tls_advertised = FALSE;
1881 #endif
1882 dsn_advertised = FALSE;
1883 #ifdef SUPPORT_I18N
1884 smtputf8_advertised = FALSE;
1885 #endif
1886
1887 /* Reset ACL connection variables */
1888
1889 acl_var_c = NULL;
1890
1891 /* Allow for trailing 0 in the command and data buffers. */
1892
1893 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1894 if (smtp_cmd_buffer == NULL)
1895 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1896 "malloc() failed for SMTP command buffer");
1897 smtp_cmd_buffer[0] = 0;
1898 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1899
1900 /* For batched input, the protocol setting can be overridden from the
1901 command line by a trusted caller. */
1902
1903 if (smtp_batched_input)
1904 {
1905 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1906 }
1907
1908 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1909 reset later if any of EHLO/AUTH/STARTTLS are received. */
1910
1911 else
1912 received_protocol =
1913 (sender_host_address ? protocols : protocols_local) [pnormal];
1914
1915 /* Set up the buffer for inputting using direct read() calls, and arrange to
1916 call the local functions instead of the standard C ones. */
1917
1918 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1919 if (smtp_inbuffer == NULL)
1920 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1921 receive_getc = smtp_getc;
1922 receive_ungetc = smtp_ungetc;
1923 receive_feof = smtp_feof;
1924 receive_ferror = smtp_ferror;
1925 receive_smtp_buffered = smtp_buffered;
1926 smtp_inptr = smtp_inend = smtp_inbuffer;
1927 smtp_had_eof = smtp_had_error = 0;
1928
1929 /* Set up the message size limit; this may be host-specific */
1930
1931 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1932 if (expand_string_message != NULL)
1933 {
1934 if (thismessage_size_limit == -1)
1935 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1936 "%s", expand_string_message);
1937 else
1938 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1939 "%s", expand_string_message);
1940 smtp_closedown(US"Temporary local problem - please try later");
1941 return FALSE;
1942 }
1943
1944 /* When a message is input locally via the -bs or -bS options, sender_host_
1945 unknown is set unless -oMa was used to force an IP address, in which case it
1946 is checked like a real remote connection. When -bs is used from inetd, this
1947 flag is not set, causing the sending host to be checked. The code that deals
1948 with IP source routing (if configured) is never required for -bs or -bS and
1949 the flag sender_host_notsocket is used to suppress it.
1950
1951 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1952 reserve for certain hosts and/or networks. */
1953
1954 if (!sender_host_unknown)
1955 {
1956 int rc;
1957 BOOL reserved_host = FALSE;
1958
1959 /* Look up IP options (source routing info) on the socket if this is not an
1960 -oMa "host", and if any are found, log them and drop the connection.
1961
1962 Linux (and others now, see below) is different to everyone else, so there
1963 has to be some conditional compilation here. Versions of Linux before 2.1.15
1964 used a structure whose name was "options". Somebody finally realized that
1965 this name was silly, and it got changed to "ip_options". I use the
1966 newer name here, but there is a fudge in the script that sets up os.h
1967 to define a macro in older Linux systems.
1968
1969 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1970 glibc 2, which has chosen ip_opts for the structure name. This is now
1971 really a glibc thing rather than a Linux thing, so the condition name
1972 has been changed to reflect this. It is relevant also to GNU/Hurd.
1973
1974 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1975 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1976 a special macro defined in the os.h file.
1977
1978 Some DGUX versions on older hardware appear not to support IP options at
1979 all, so there is now a general macro which can be set to cut out this
1980 support altogether.
1981
1982 How to do this properly in IPv6 is not yet known. */
1983
1984 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1985
1986 #ifdef GLIBC_IP_OPTIONS
1987 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1988 #define OPTSTYLE 1
1989 #else
1990 #define OPTSTYLE 2
1991 #endif
1992 #elif defined DARWIN_IP_OPTIONS
1993 #define OPTSTYLE 2
1994 #else
1995 #define OPTSTYLE 3
1996 #endif
1997
1998 if (!host_checking && !sender_host_notsocket)
1999 {
2000 #if OPTSTYLE == 1
2001 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2002 struct ip_options *ipopt = store_get(optlen);
2003 #elif OPTSTYLE == 2
2004 struct ip_opts ipoptblock;
2005 struct ip_opts *ipopt = &ipoptblock;
2006 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2007 #else
2008 struct ipoption ipoptblock;
2009 struct ipoption *ipopt = &ipoptblock;
2010 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2011 #endif
2012
2013 /* Occasional genuine failures of getsockopt() have been seen - for
2014 example, "reset by peer". Therefore, just log and give up on this
2015 call, unless the error is ENOPROTOOPT. This error is given by systems
2016 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2017 of writing. So for that error, carry on - we just can't do an IP options
2018 check. */
2019
2020 DEBUG(D_receive) debug_printf("checking for IP options\n");
2021
2022 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2023 &optlen) < 0)
2024 {
2025 if (errno != ENOPROTOOPT)
2026 {
2027 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2028 host_and_ident(FALSE), strerror(errno));
2029 smtp_printf("451 SMTP service not available\r\n");
2030 return FALSE;
2031 }
2032 }
2033
2034 /* Deal with any IP options that are set. On the systems I have looked at,
2035 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2036 more logging data than will fit in big_buffer. Nevertheless, after somebody
2037 questioned this code, I've added in some paranoid checking. */
2038
2039 else if (optlen > 0)
2040 {
2041 uschar *p = big_buffer;
2042 uschar *pend = big_buffer + big_buffer_size;
2043 uschar *opt, *adptr;
2044 int optcount;
2045 struct in_addr addr;
2046
2047 #if OPTSTYLE == 1
2048 uschar *optstart = (uschar *)(ipopt->__data);
2049 #elif OPTSTYLE == 2
2050 uschar *optstart = (uschar *)(ipopt->ip_opts);
2051 #else
2052 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2053 #endif
2054
2055 DEBUG(D_receive) debug_printf("IP options exist\n");
2056
2057 Ustrcpy(p, "IP options on incoming call:");
2058 p += Ustrlen(p);
2059
2060 for (opt = optstart; opt != NULL &&
2061 opt < (uschar *)(ipopt) + optlen;)
2062 {
2063 switch (*opt)
2064 {
2065 case IPOPT_EOL:
2066 opt = NULL;
2067 break;
2068
2069 case IPOPT_NOP:
2070 opt++;
2071 break;
2072
2073 case IPOPT_SSRR:
2074 case IPOPT_LSRR:
2075 if (!string_format(p, pend-p, " %s [@%s",
2076 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2077 #if OPTSTYLE == 1
2078 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2079 #elif OPTSTYLE == 2
2080 inet_ntoa(ipopt->ip_dst)))
2081 #else
2082 inet_ntoa(ipopt->ipopt_dst)))
2083 #endif
2084 {
2085 opt = NULL;
2086 break;
2087 }
2088
2089 p += Ustrlen(p);
2090 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2091 adptr = opt + 3;
2092 while (optcount-- > 0)
2093 {
2094 memcpy(&addr, adptr, sizeof(addr));
2095 if (!string_format(p, pend - p - 1, "%s%s",
2096 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2097 {
2098 opt = NULL;
2099 break;
2100 }
2101 p += Ustrlen(p);
2102 adptr += sizeof(struct in_addr);
2103 }
2104 *p++ = ']';
2105 opt += opt[1];
2106 break;
2107
2108 default:
2109 {
2110 int i;
2111 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2112 Ustrcat(p, "[ ");
2113 p += 2;
2114 for (i = 0; i < opt[1]; i++)
2115 {
2116 sprintf(CS p, "%2.2x ", opt[i]);
2117 p += 3;
2118 }
2119 *p++ = ']';
2120 }
2121 opt += opt[1];
2122 break;
2123 }
2124 }
2125
2126 *p = 0;
2127 log_write(0, LOG_MAIN, "%s", big_buffer);
2128
2129 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2130
2131 log_write(0, LOG_MAIN|LOG_REJECT,
2132 "connection from %s refused (IP options)", host_and_ident(FALSE));
2133
2134 smtp_printf("554 SMTP service not available\r\n");
2135 return FALSE;
2136 }
2137
2138 /* Length of options = 0 => there are no options */
2139
2140 else DEBUG(D_receive) debug_printf("no IP options found\n");
2141 }
2142 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2143
2144 /* Set keep-alive in socket options. The option is on by default. This
2145 setting is an attempt to get rid of some hanging connections that stick in
2146 read() when the remote end (usually a dialup) goes away. */
2147
2148 if (smtp_accept_keepalive && !sender_host_notsocket)
2149 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2150
2151 /* If the current host matches host_lookup, set the name by doing a
2152 reverse lookup. On failure, sender_host_name will be NULL and
2153 host_lookup_failed will be TRUE. This may or may not be serious - optional
2154 checks later. */
2155
2156 if (verify_check_host(&host_lookup) == OK)
2157 {
2158 (void)host_name_lookup();
2159 host_build_sender_fullhost();
2160 }
2161
2162 /* Delay this until we have the full name, if it is looked up. */
2163
2164 set_process_info("handling incoming connection from %s",
2165 host_and_ident(FALSE));
2166
2167 /* Expand smtp_receive_timeout, if needed */
2168
2169 if (smtp_receive_timeout_s)
2170 {
2171 uschar * exp;
2172 if ( !(exp = expand_string(smtp_receive_timeout_s))
2173 || !(*exp)
2174 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2175 )
2176 log_write(0, LOG_MAIN|LOG_PANIC,
2177 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2178 }
2179
2180 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2181 smtps port for use with older style SSL MTAs. */
2182
2183 #ifdef SUPPORT_TLS
2184 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2185 return FALSE;
2186 #endif
2187
2188 /* Test for explicit connection rejection */
2189
2190 if (verify_check_host(&host_reject_connection) == OK)
2191 {
2192 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2193 "from %s (host_reject_connection)", host_and_ident(FALSE));
2194 smtp_printf("554 SMTP service not available\r\n");
2195 return FALSE;
2196 }
2197
2198 /* Test with TCP Wrappers if so configured. There is a problem in that
2199 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2200 such as disks dying. In these cases, it is desirable to reject with a 4xx
2201 error instead of a 5xx error. There isn't a "right" way to detect such
2202 problems. The following kludge is used: errno is zeroed before calling
2203 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2204 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2205 not exist). */
2206
2207 #ifdef USE_TCP_WRAPPERS
2208 errno = 0;
2209 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2210 if (tcp_wrappers_name == NULL)
2211 {
2212 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2213 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2214 expand_string_message);
2215 }
2216 if (!hosts_ctl(tcp_wrappers_name,
2217 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2218 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2219 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2220 {
2221 if (errno == 0 || errno == ENOENT)
2222 {
2223 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2224 log_write(L_connection_reject,
2225 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2226 "(tcp wrappers)", host_and_ident(FALSE));
2227 smtp_printf("554 SMTP service not available\r\n");
2228 }
2229 else
2230 {
2231 int save_errno = errno;
2232 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2233 "errno value %d\n", save_errno);
2234 log_write(L_connection_reject,
2235 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2236 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2237 smtp_printf("451 Temporary local problem - please try later\r\n");
2238 }
2239 return FALSE;
2240 }
2241 #endif
2242
2243 /* Check for reserved slots. The value of smtp_accept_count has already been
2244 incremented to include this process. */
2245
2246 if (smtp_accept_max > 0 &&
2247 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2248 {
2249 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2250 {
2251 log_write(L_connection_reject,
2252 LOG_MAIN, "temporarily refused connection from %s: not in "
2253 "reserve list: connected=%d max=%d reserve=%d%s",
2254 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2255 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2256 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2257 "please try again later\r\n", smtp_active_hostname);
2258 return FALSE;
2259 }
2260 reserved_host = TRUE;
2261 }
2262
2263 /* If a load level above which only messages from reserved hosts are
2264 accepted is set, check the load. For incoming calls via the daemon, the
2265 check is done in the superior process if there are no reserved hosts, to
2266 save a fork. In all cases, the load average will already be available
2267 in a global variable at this point. */
2268
2269 if (smtp_load_reserve >= 0 &&
2270 load_average > smtp_load_reserve &&
2271 !reserved_host &&
2272 verify_check_host(&smtp_reserve_hosts) != OK)
2273 {
2274 log_write(L_connection_reject,
2275 LOG_MAIN, "temporarily refused connection from %s: not in "
2276 "reserve list and load average = %.2f", host_and_ident(FALSE),
2277 (double)load_average/1000.0);
2278 smtp_printf("421 %s: Too much load; please try again later\r\n",
2279 smtp_active_hostname);
2280 return FALSE;
2281 }
2282
2283 /* Determine whether unqualified senders or recipients are permitted
2284 for this host. Unfortunately, we have to do this every time, in order to
2285 set the flags so that they can be inspected when considering qualifying
2286 addresses in the headers. For a site that permits no qualification, this
2287 won't take long, however. */
2288
2289 allow_unqualified_sender =
2290 verify_check_host(&sender_unqualified_hosts) == OK;
2291
2292 allow_unqualified_recipient =
2293 verify_check_host(&recipient_unqualified_hosts) == OK;
2294
2295 /* Determine whether HELO/EHLO is required for this host. The requirement
2296 can be hard or soft. */
2297
2298 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2299 if (!helo_required)
2300 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2301
2302 /* Determine whether this hosts is permitted to send syntactic junk
2303 after a HELO or EHLO command. */
2304
2305 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2306 }
2307
2308 /* For batch SMTP input we are now done. */
2309
2310 if (smtp_batched_input) return TRUE;
2311
2312 #ifdef SUPPORT_PROXY
2313 /* If valid Proxy Protocol source is connecting, set up session.
2314 * Failure will not allow any SMTP function other than QUIT. */
2315 proxy_session = FALSE;
2316 proxy_session_failed = FALSE;
2317 if (check_proxy_protocol_host())
2318 {
2319 if (setup_proxy_protocol_host() == FALSE)
2320 {
2321 proxy_session_failed = TRUE;
2322 DEBUG(D_receive)
2323 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2324 }
2325 else
2326 {
2327 sender_host_name = NULL;
2328 (void)host_name_lookup();
2329 host_build_sender_fullhost();
2330 }
2331 }
2332 #endif
2333
2334 /* Run the ACL if it exists */
2335
2336 user_msg = NULL;
2337 if (acl_smtp_connect != NULL)
2338 {
2339 int rc;
2340 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2341 &log_msg);
2342 if (rc != OK)
2343 {
2344 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2345 return FALSE;
2346 }
2347 }
2348
2349 /* Output the initial message for a two-way SMTP connection. It may contain
2350 newlines, which then cause a multi-line response to be given. */
2351
2352 code = US"220"; /* Default status code */
2353 esc = US""; /* Default extended status code */
2354 esclen = 0; /* Length of esc */
2355
2356 if (!user_msg)
2357 {
2358 if (!(s = expand_string(smtp_banner)))
2359 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2360 "failed: %s", smtp_banner, expand_string_message);
2361 }
2362 else
2363 {
2364 int codelen = 3;
2365 s = user_msg;
2366 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2367 if (codelen > 4)
2368 {
2369 esc = code + 4;
2370 esclen = codelen - 4;
2371 }
2372 }
2373
2374 /* Remove any terminating newlines; might as well remove trailing space too */
2375
2376 p = s + Ustrlen(s);
2377 while (p > s && isspace(p[-1])) p--;
2378 *p = 0;
2379
2380 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2381 is all contained in a single IP packet. The original code wrote out the
2382 greeting using several calls to fprint/fputc, and on busy servers this could
2383 cause it to be split over more than one packet - which caused CC:Mail to fall
2384 over when it got the second part of the greeting after sending its first
2385 command. Sigh. To try to avoid this, build the complete greeting message
2386 first, and output it in one fell swoop. This gives a better chance of it
2387 ending up as a single packet. */
2388
2389 ss = store_get(size);
2390 ptr = 0;
2391
2392 p = s;
2393 do /* At least once, in case we have an empty string */
2394 {
2395 int len;
2396 uschar *linebreak = Ustrchr(p, '\n');
2397 ss = string_catn(ss, &size, &ptr, code, 3);
2398 if (linebreak == NULL)
2399 {
2400 len = Ustrlen(p);
2401 ss = string_catn(ss, &size, &ptr, US" ", 1);
2402 }
2403 else
2404 {
2405 len = linebreak - p;
2406 ss = string_catn(ss, &size, &ptr, US"-", 1);
2407 }
2408 ss = string_catn(ss, &size, &ptr, esc, esclen);
2409 ss = string_catn(ss, &size, &ptr, p, len);
2410 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2411 p += len;
2412 if (linebreak != NULL) p++;
2413 }
2414 while (*p != 0);
2415
2416 ss[ptr] = 0; /* string_cat leaves room for this */
2417
2418 /* Before we write the banner, check that there is no input pending, unless
2419 this synchronisation check is disabled. */
2420
2421 if (!check_sync())
2422 {
2423 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2424 "synchronization error (input sent without waiting for greeting): "
2425 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2426 string_printing(smtp_inptr));
2427 smtp_printf("554 SMTP synchronization error\r\n");
2428 return FALSE;
2429 }
2430
2431 /* Now output the banner */
2432
2433 smtp_printf("%s", ss);
2434 return TRUE;
2435 }
2436
2437
2438
2439
2440
2441 /*************************************************
2442 * Handle SMTP syntax and protocol errors *
2443 *************************************************/
2444
2445 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2446 to do so. Then transmit the error response. The return value depends on the
2447 number of syntax and protocol errors in this SMTP session.
2448
2449 Arguments:
2450 type error type, given as a log flag bit
2451 code response code; <= 0 means don't send a response
2452 data data to reflect in the response (can be NULL)
2453 errmess the error message
2454
2455 Returns: -1 limit of syntax/protocol errors NOT exceeded
2456 +1 limit of syntax/protocol errors IS exceeded
2457
2458 These values fit in with the values of the "done" variable in the main
2459 processing loop in smtp_setup_msg(). */
2460
2461 static int
2462 synprot_error(int type, int code, uschar *data, uschar *errmess)
2463 {
2464 int yield = -1;
2465
2466 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2467 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2468 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2469
2470 if (++synprot_error_count > smtp_max_synprot_errors)
2471 {
2472 yield = 1;
2473 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2474 "syntax or protocol errors (last command was \"%s\")",
2475 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2476 }
2477
2478 if (code > 0)
2479 {
2480 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2481 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2482 if (yield == 1)
2483 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2484 }
2485
2486 return yield;
2487 }
2488
2489
2490
2491
2492 /*************************************************
2493 * Log incomplete transactions *
2494 *************************************************/
2495
2496 /* This function is called after a transaction has been aborted by RSET, QUIT,
2497 connection drops or other errors. It logs the envelope information received
2498 so far in order to preserve address verification attempts.
2499
2500 Argument: string to indicate what aborted the transaction
2501 Returns: nothing
2502 */
2503
2504 static void
2505 incomplete_transaction_log(uschar *what)
2506 {
2507 if (sender_address == NULL || /* No transaction in progress */
2508 !LOGGING(smtp_incomplete_transaction))
2509 return;
2510
2511 /* Build list of recipients for logging */
2512
2513 if (recipients_count > 0)
2514 {
2515 int i;
2516 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2517 for (i = 0; i < recipients_count; i++)
2518 raw_recipients[i] = recipients_list[i].address;
2519 raw_recipients_count = recipients_count;
2520 }
2521
2522 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2523 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2524 }
2525
2526
2527
2528
2529 /*************************************************
2530 * Send SMTP response, possibly multiline *
2531 *************************************************/
2532
2533 /* There are, it seems, broken clients out there that cannot handle multiline
2534 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2535 output nothing for non-final calls, and only the first line for anything else.
2536
2537 Arguments:
2538 code SMTP code, may involve extended status codes
2539 codelen length of smtp code; if > 4 there's an ESC
2540 final FALSE if the last line isn't the final line
2541 msg message text, possibly containing newlines
2542
2543 Returns: nothing
2544 */
2545
2546 void
2547 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2548 {
2549 int esclen = 0;
2550 uschar *esc = US"";
2551
2552 if (!final && no_multiline_responses) return;
2553
2554 if (codelen > 4)
2555 {
2556 esc = code + 4;
2557 esclen = codelen - 4;
2558 }
2559
2560 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2561 have had the same. Note: this code is also present in smtp_printf(). It would
2562 be tidier to have it only in one place, but when it was added, it was easier to
2563 do it that way, so as not to have to mess with the code for the RCPT command,
2564 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2565
2566 if (rcpt_in_progress)
2567 {
2568 if (rcpt_smtp_response == NULL)
2569 rcpt_smtp_response = string_copy(msg);
2570 else if (rcpt_smtp_response_same &&
2571 Ustrcmp(rcpt_smtp_response, msg) != 0)
2572 rcpt_smtp_response_same = FALSE;
2573 rcpt_in_progress = FALSE;
2574 }
2575
2576 /* Not output the message, splitting it up into multiple lines if necessary. */
2577
2578 for (;;)
2579 {
2580 uschar *nl = Ustrchr(msg, '\n');
2581 if (nl == NULL)
2582 {
2583 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2584 return;
2585 }
2586 else if (nl[1] == 0 || no_multiline_responses)
2587 {
2588 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2589 (int)(nl - msg), msg);
2590 return;
2591 }
2592 else
2593 {
2594 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2595 msg = nl + 1;
2596 while (isspace(*msg)) msg++;
2597 }
2598 }
2599 }
2600
2601
2602
2603
2604 /*************************************************
2605 * Parse user SMTP message *
2606 *************************************************/
2607
2608 /* This function allows for user messages overriding the response code details
2609 by providing a suitable response code string at the start of the message
2610 user_msg. Check the message for starting with a response code and optionally an
2611 extended status code. If found, check that the first digit is valid, and if so,
2612 change the code pointer and length to use the replacement. An invalid code
2613 causes a panic log; in this case, if the log messages is the same as the user
2614 message, we must also adjust the value of the log message to show the code that
2615 is actually going to be used (the original one).
2616
2617 This function is global because it is called from receive.c as well as within
2618 this module.
2619
2620 Note that the code length returned includes the terminating whitespace
2621 character, which is always included in the regex match.
2622
2623 Arguments:
2624 code SMTP code, may involve extended status codes
2625 codelen length of smtp code; if > 4 there's an ESC
2626 msg message text
2627 log_msg optional log message, to be adjusted with the new SMTP code
2628 check_valid if true, verify the response code
2629
2630 Returns: nothing
2631 */
2632
2633 void
2634 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2635 BOOL check_valid)
2636 {
2637 int n;
2638 int ovector[3];
2639
2640 if (!msg || !*msg) return;
2641
2642 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2643 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
2644
2645 if (check_valid && (*msg)[0] != (*code)[0])
2646 {
2647 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2648 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2649 if (log_msg != NULL && *log_msg == *msg)
2650 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2651 }
2652 else
2653 {
2654 *code = *msg;
2655 *codelen = ovector[1]; /* Includes final space */
2656 }
2657 *msg += ovector[1]; /* Chop the code off the message */
2658 return;
2659 }
2660
2661
2662
2663
2664 /*************************************************
2665 * Handle an ACL failure *
2666 *************************************************/
2667
2668 /* This function is called when acl_check() fails. As well as calls from within
2669 this module, it is called from receive.c for an ACL after DATA. It sorts out
2670 logging the incident, and sets up the error response. A message containing
2671 newlines is turned into a multiline SMTP response, but for logging, only the
2672 first line is used.
2673
2674 There's a table of default permanent failure response codes to use in
2675 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2676 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2677 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2678 state, because there are broken clients that try VRFY before RCPT. A 5xx
2679 response should be given only when the address is positively known to be
2680 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2681 no explicit code, but if there is one we let it know best.
2682 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2683
2684 From Exim 4.63, it is possible to override the response code details by
2685 providing a suitable response code string at the start of the message provided
2686 in user_msg. The code's first digit is checked for validity.
2687
2688 Arguments:
2689 where where the ACL was called from
2690 rc the failure code
2691 user_msg a message that can be included in an SMTP response
2692 log_msg a message for logging
2693
2694 Returns: 0 in most cases
2695 2 if the failure code was FAIL_DROP, in which case the
2696 SMTP connection should be dropped (this value fits with the
2697 "done" variable in smtp_setup_msg() below)
2698 */
2699
2700 int
2701 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2702 {
2703 BOOL drop = rc == FAIL_DROP;
2704 int codelen = 3;
2705 uschar *smtp_code;
2706 uschar *lognl;
2707 uschar *sender_info = US"";
2708 uschar *what =
2709 #ifdef WITH_CONTENT_SCAN
2710 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2711 #endif
2712 (where == ACL_WHERE_PREDATA)? US"DATA" :
2713 (where == ACL_WHERE_DATA)? US"after DATA" :
2714 #ifndef DISABLE_PRDR
2715 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2716 #endif
2717 (smtp_cmd_data == NULL)?
2718 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2719 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2720
2721 if (drop) rc = FAIL;
2722
2723 /* Set the default SMTP code, and allow a user message to change it. */
2724
2725 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2726 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2727 where != ACL_WHERE_VRFY);
2728
2729 /* We used to have sender_address here; however, there was a bug that was not
2730 updating sender_address after a rewrite during a verify. When this bug was
2731 fixed, sender_address at this point became the rewritten address. I'm not sure
2732 this is what should be logged, so I've changed to logging the unrewritten
2733 address to retain backward compatibility. */
2734
2735 #ifndef WITH_CONTENT_SCAN
2736 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2737 #else
2738 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2739 #endif
2740 {
2741 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2742 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2743 sender_host_authenticated ? US" A=" : US"",
2744 sender_host_authenticated ? sender_host_authenticated : US"",
2745 sender_host_authenticated && authenticated_id ? US":" : US"",
2746 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2747 );
2748 }
2749
2750 /* If there's been a sender verification failure with a specific message, and
2751 we have not sent a response about it yet, do so now, as a preliminary line for
2752 failures, but not defers. However, always log it for defer, and log it for fail
2753 unless the sender_verify_fail log selector has been turned off. */
2754
2755 if (sender_verified_failed != NULL &&
2756 !testflag(sender_verified_failed, af_sverify_told))
2757 {
2758 BOOL save_rcpt_in_progress = rcpt_in_progress;
2759 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2760
2761 setflag(sender_verified_failed, af_sverify_told);
2762
2763 if (rc != FAIL || LOGGING(sender_verify_fail))
2764 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2765 host_and_ident(TRUE),
2766 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2767 sender_verified_failed->address,
2768 (sender_verified_failed->message == NULL)? US"" :
2769 string_sprintf(": %s", sender_verified_failed->message));
2770
2771 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2772 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2773 testflag(sender_verified_failed, af_verify_pmfail)?
2774 "Postmaster verification failed while checking <%s>\n%s\n"
2775 "Several RFCs state that you are required to have a postmaster\n"
2776 "mailbox for each mail domain. This host does not accept mail\n"
2777 "from domains whose servers reject the postmaster address."
2778 :
2779 testflag(sender_verified_failed, af_verify_nsfail)?
2780 "Callback setup failed while verifying <%s>\n%s\n"
2781 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2782 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2783 "RFC requirements, and stops you from receiving standard bounce\n"
2784 "messages. This host does not accept mail from domains whose servers\n"
2785 "refuse bounces."
2786 :
2787 "Verification failed for <%s>\n%s",
2788 sender_verified_failed->address,
2789 sender_verified_failed->user_message));
2790
2791 rcpt_in_progress = save_rcpt_in_progress;
2792 }
2793
2794 /* Sort out text for logging */
2795
2796 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2797 lognl = Ustrchr(log_msg, '\n');
2798 if (lognl != NULL) *lognl = 0;
2799
2800 /* Send permanent failure response to the command, but the code used isn't
2801 always a 5xx one - see comments at the start of this function. If the original
2802 rc was FAIL_DROP we drop the connection and yield 2. */
2803
2804 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2805 US"Administrative prohibition" : user_msg);
2806
2807 /* Send temporary failure response to the command. Don't give any details,
2808 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2809 verb, and for a header verify when smtp_return_error_details is set.
2810
2811 This conditional logic is all somewhat of a mess because of the odd
2812 interactions between temp_details and return_error_details. One day it should
2813 be re-implemented in a tidier fashion. */
2814
2815 else
2816 {
2817 if (acl_temp_details && user_msg != NULL)
2818 {
2819 if (smtp_return_error_details &&
2820 sender_verified_failed != NULL &&
2821 sender_verified_failed->message != NULL)
2822 {
2823 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2824 }
2825 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2826 }
2827 else
2828 smtp_respond(smtp_code, codelen, TRUE,
2829 US"Temporary local problem - please try later");
2830 }
2831
2832 /* Log the incident to the logs that are specified by log_reject_target
2833 (default main, reject). This can be empty to suppress logging of rejections. If
2834 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2835 is closing if required and return 2. */
2836
2837 if (log_reject_target != 0)
2838 {
2839 #ifdef SUPPORT_TLS
2840 uschar * tls = s_tlslog(NULL, NULL, NULL);
2841 if (!tls) tls = US"";
2842 #else
2843 uschar * tls = US"";
2844 #endif
2845 log_write(0, log_reject_target, "%s%s%s %s%srejected %s%s",
2846 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
2847 host_and_ident(TRUE),
2848 tls,
2849 sender_info,
2850 rc == FAIL ? US"" : US"temporarily ",
2851 what, log_msg);
2852 }
2853
2854 if (!drop) return 0;
2855
2856 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2857 smtp_get_connection_info());
2858
2859 /* Run the not-quit ACL, but without any custom messages. This should not be a
2860 problem, because we get here only if some other ACL has issued "drop", and
2861 in that case, *its* custom messages will have been used above. */
2862
2863 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2864 return 2;
2865 }
2866
2867
2868
2869
2870 /*************************************************
2871 * Handle SMTP exit when QUIT is not given *
2872 *************************************************/
2873
2874 /* This function provides a logging/statistics hook for when an SMTP connection
2875 is dropped on the floor or the other end goes away. It's a global function
2876 because it's called from receive.c as well as this module. As well as running
2877 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2878 response, either with a custom message from the ACL, or using a default. There
2879 is one case, however, when no message is output - after "drop". In that case,
2880 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2881 passed to this function.
2882
2883 In case things go wrong while processing this function, causing an error that
2884 may re-enter this funtion, there is a recursion check.
2885
2886 Arguments:
2887 reason What $smtp_notquit_reason will be set to in the ACL;
2888 if NULL, the ACL is not run
2889 code The error code to return as part of the response
2890 defaultrespond The default message if there's no user_msg
2891
2892 Returns: Nothing
2893 */
2894
2895 void
2896 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2897 {
2898 int rc;
2899 uschar *user_msg = NULL;
2900 uschar *log_msg = NULL;
2901
2902 /* Check for recursive acll */
2903
2904 if (smtp_exit_function_called)
2905 {
2906 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2907 reason);
2908 return;
2909 }
2910 smtp_exit_function_called = TRUE;
2911
2912 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2913
2914 if (acl_smtp_notquit != NULL && reason != NULL)
2915 {
2916 smtp_notquit_reason = reason;
2917 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2918 &log_msg);
2919 if (rc == ERROR)
2920 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2921 log_msg);
2922 }
2923
2924 /* Write an SMTP response if we are expected to give one. As the default
2925 responses are all internal, they should always fit in the buffer, but code a
2926 warning, just in case. Note that string_vformat() still leaves a complete
2927 string, even if it is incomplete. */
2928
2929 if (code != NULL && defaultrespond != NULL)
2930 {
2931 if (user_msg == NULL)
2932 {
2933 uschar buffer[128];
2934 va_list ap;
2935 va_start(ap, defaultrespond);
2936 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2937 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2938 smtp_printf("%s %s\r\n", code, buffer);
2939 va_end(ap);
2940 }
2941 else
2942 smtp_respond(code, 3, TRUE, user_msg);
2943 mac_smtp_fflush();
2944 }
2945 }
2946
2947
2948
2949
2950 /*************************************************
2951 * Verify HELO argument *
2952 *************************************************/
2953
2954 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2955 matched. It is also called from ACL processing if verify = helo is used and
2956 verification was not previously tried (i.e. helo_try_verify_hosts was not
2957 matched). The result of its processing is to set helo_verified and
2958 helo_verify_failed. These variables should both be FALSE for this function to
2959 be called.
2960
2961 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2962 for IPv6 ::ffff: literals.
2963
2964 Argument: none
2965 Returns: TRUE if testing was completed;
2966 FALSE on a temporary failure
2967 */
2968
2969 BOOL
2970 smtp_verify_helo(void)
2971 {
2972 BOOL yield = TRUE;
2973
2974 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2975 sender_helo_name);
2976
2977 if (sender_helo_name == NULL)
2978 {
2979 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2980 }
2981
2982 /* Deal with the case of -bs without an IP address */
2983
2984 else if (sender_host_address == NULL)
2985 {
2986 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2987 helo_verified = TRUE;
2988 }
2989
2990 /* Deal with the more common case when there is a sending IP address */
2991
2992 else if (sender_helo_name[0] == '[')
2993 {
2994 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2995 Ustrlen(sender_host_address)) == 0;
2996
2997 #if HAVE_IPV6
2998 if (!helo_verified)
2999 {
3000 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3001 helo_verified = Ustrncmp(sender_helo_name + 1,
3002 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3003 }
3004 #endif
3005
3006 HDEBUG(D_receive)
3007 { if (helo_verified) debug_printf("matched host address\n"); }
3008 }
3009
3010 /* Do a reverse lookup if one hasn't already given a positive or negative
3011 response. If that fails, or the name doesn't match, try checking with a forward
3012 lookup. */
3013
3014 else
3015 {
3016 if (sender_host_name == NULL && !host_lookup_failed)
3017 yield = host_name_lookup() != DEFER;
3018
3019 /* If a host name is known, check it and all its aliases. */
3020
3021 if (sender_host_name)
3022 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3023 {
3024 sender_helo_dnssec = sender_host_dnssec;
3025 HDEBUG(D_receive) debug_printf("matched host name\n");
3026 }
3027 else
3028 {
3029 uschar **aliases = sender_host_aliases;
3030 while (*aliases)
3031 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3032 {
3033 sender_helo_dnssec = sender_host_dnssec;
3034 break;
3035 }
3036
3037 HDEBUG(D_receive) if (helo_verified)
3038 debug_printf("matched alias %s\n", *(--aliases));
3039 }
3040
3041 /* Final attempt: try a forward lookup of the helo name */
3042
3043 if (!helo_verified)
3044 {
3045 int rc;
3046 host_item h;
3047 dnssec_domains d;
3048 host_item *hh;
3049
3050 h.name = sender_helo_name;
3051 h.address = NULL;
3052 h.mx = MX_NONE;
3053 h.next = NULL;
3054 d.request = US"*";
3055 d.require = US"";
3056
3057 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3058 sender_helo_name);
3059 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3060 NULL, NULL, NULL, &d, NULL, NULL);
3061 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3062 for (hh = &h; hh; hh = hh->next)
3063 if (Ustrcmp(hh->address, sender_host_address) == 0)
3064 {
3065 helo_verified = TRUE;
3066 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3067 HDEBUG(D_receive)
3068 {
3069 debug_printf("IP address for %s matches calling address\n"
3070 "Forward DNS security status: %sverified\n",
3071 sender_helo_name, sender_helo_dnssec ? "" : "un");
3072 }
3073 break;
3074 }
3075 }
3076 }
3077
3078 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3079 return yield;
3080 }
3081
3082
3083
3084
3085 /*************************************************
3086 * Send user response message *
3087 *************************************************/
3088
3089 /* This function is passed a default response code and a user message. It calls
3090 smtp_message_code() to check and possibly modify the response code, and then
3091 calls smtp_respond() to transmit the response. I put this into a function
3092 just to avoid a lot of repetition.
3093
3094 Arguments:
3095 code the response code
3096 user_msg the user message
3097
3098 Returns: nothing
3099 */
3100
3101 static void
3102 smtp_user_msg(uschar *code, uschar *user_msg)
3103 {
3104 int len = 3;
3105 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3106 smtp_respond(code, len, TRUE, user_msg);
3107 }
3108
3109
3110
3111 static int
3112 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3113 {
3114 const uschar *set_id = NULL;
3115 int rc, i;
3116
3117 /* Run the checking code, passing the remainder of the command line as
3118 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3119 it as the only set numerical variable. The authenticator may set $auth<n>
3120 and also set other numeric variables. The $auth<n> variables are preferred
3121 nowadays; the numerical variables remain for backwards compatibility.
3122
3123 Afterwards, have a go at expanding the set_id string, even if
3124 authentication failed - for bad passwords it can be useful to log the
3125 userid. On success, require set_id to expand and exist, and put it in
3126 authenticated_id. Save this in permanent store, as the working store gets
3127 reset at HELO, RSET, etc. */
3128
3129 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3130 expand_nmax = 0;
3131 expand_nlength[0] = 0; /* $0 contains nothing */
3132
3133 rc = (au->info->servercode)(au, smtp_cmd_data);
3134 if (au->set_id) set_id = expand_string(au->set_id);
3135 expand_nmax = -1; /* Reset numeric variables */
3136 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3137
3138 /* The value of authenticated_id is stored in the spool file and printed in
3139 log lines. It must not contain binary zeros or newline characters. In
3140 normal use, it never will, but when playing around or testing, this error
3141 can (did) happen. To guard against this, ensure that the id contains only
3142 printing characters. */
3143
3144 if (set_id) set_id = string_printing(set_id);
3145
3146 /* For the non-OK cases, set up additional logging data if set_id
3147 is not empty. */
3148
3149 if (rc != OK)
3150 set_id = set_id && *set_id
3151 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3152
3153 /* Switch on the result */
3154
3155 switch(rc)
3156 {
3157 case OK:
3158 if (!au->set_id || set_id) /* Complete success */
3159 {
3160 if (set_id) authenticated_id = string_copy_malloc(set_id);
3161 sender_host_authenticated = au->name;
3162 authentication_failed = FALSE;
3163 authenticated_fail_id = NULL; /* Impossible to already be set? */
3164
3165 received_protocol =
3166 (sender_host_address ? protocols : protocols_local)
3167 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3168 *s = *ss = US"235 Authentication succeeded";
3169 authenticated_by = au;
3170 break;
3171 }
3172
3173 /* Authentication succeeded, but we failed to expand the set_id string.
3174 Treat this as a temporary error. */
3175
3176 auth_defer_msg = expand_string_message;
3177 /* Fall through */
3178
3179 case DEFER:
3180 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3181 *s = string_sprintf("435 Unable to authenticate at present%s",
3182 auth_defer_user_msg);
3183 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3184 set_id, auth_defer_msg);
3185 break;
3186
3187 case BAD64:
3188 *s = *ss = US"501 Invalid base64 data";
3189 break;
3190
3191 case CANCELLED:
3192 *s = *ss = US"501 Authentication cancelled";
3193 break;
3194
3195 case UNEXPECTED:
3196 *s = *ss = US"553 Initial data not expected";
3197 break;
3198
3199 case FAIL:
3200 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3201 *s = US"535 Incorrect authentication data";
3202 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3203 break;
3204
3205 default:
3206 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3207 *s = US"435 Internal error";
3208 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3209 "check", set_id, rc);
3210 break;
3211 }
3212
3213 return rc;
3214 }
3215
3216
3217
3218 /*************************************************
3219 * Initialize for SMTP incoming message *
3220 *************************************************/
3221
3222 /* This function conducts the initial dialogue at the start of an incoming SMTP
3223 message, and builds a list of recipients. However, if the incoming message
3224 is part of a batch (-bS option) a separate function is called since it would
3225 be messy having tests splattered about all over this function. This function
3226 therefore handles the case where interaction is occurring. The input and output
3227 files are set up in smtp_in and smtp_out.
3228
3229 The global recipients_list is set to point to a vector of recipient_item
3230 blocks, whose number is given by recipients_count. This is extended by the
3231 receive_add_recipient() function. The global variable sender_address is set to
3232 the sender's address. The yield is +1 if a message has been successfully
3233 started, 0 if a QUIT command was encountered or the connection was refused from
3234 the particular host, or -1 if the connection was lost.
3235
3236 Argument: none
3237
3238 Returns: > 0 message successfully started (reached DATA)
3239 = 0 QUIT read or end of file reached or call refused
3240 < 0 lost connection
3241 */
3242
3243 int
3244 smtp_setup_msg(void)
3245 {
3246 int done = 0;
3247 BOOL toomany = FALSE;
3248 BOOL discarded = FALSE;
3249 BOOL last_was_rej_mail = FALSE;
3250 BOOL last_was_rcpt = FALSE;
3251 void *reset_point = store_get(0);
3252
3253 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3254
3255 /* Reset for start of new message. We allow one RSET not to be counted as a
3256 nonmail command, for those MTAs that insist on sending it between every
3257 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3258 TLS between messages (an Exim client may do this if it has messages queued up
3259 for the host). Note: we do NOT reset AUTH at this point. */
3260
3261 smtp_reset(reset_point);
3262 message_ended = END_NOTSTARTED;
3263
3264 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3265 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3266 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3267 #ifdef SUPPORT_TLS
3268 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3269 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3270 #endif
3271
3272 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3273
3274 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3275
3276 /* Batched SMTP is handled in a different function. */
3277
3278 if (smtp_batched_input) return smtp_setup_batch_msg();
3279
3280 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3281 value. The values are 2 larger than the required yield of the function. */
3282
3283 while (done <= 0)
3284 {
3285 const uschar **argv;
3286 uschar *etrn_command;
3287 uschar *etrn_serialize_key;
3288 uschar *errmess;
3289 uschar *log_msg, *smtp_code;
3290 uschar *user_msg = NULL;
3291 uschar *recipient = NULL;
3292 uschar *hello = NULL;
3293 uschar *s, *ss;
3294 BOOL was_rej_mail = FALSE;
3295 BOOL was_rcpt = FALSE;
3296 void (*oldsignal)(int);
3297 pid_t pid;
3298 int start, end, sender_domain, recipient_domain;
3299 int ptr, size, rc;
3300 int c;
3301 auth_instance *au;
3302 uschar *orcpt = NULL;
3303 int flags;
3304
3305 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3306 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3307 if ( tls_in.active >= 0
3308 && tls_in.peercert
3309 && tls_in.certificate_verified
3310 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3311 )
3312 {
3313 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3314 if ( acl_smtp_auth
3315 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3316 &user_msg, &log_msg)) != OK
3317 )
3318 {
3319 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3320 continue;
3321 }
3322
3323 for (au = auths; au; au = au->next)
3324 if (strcmpic(US"tls", au->driver_name) == 0)
3325 {
3326 smtp_cmd_data = NULL;
3327
3328 if (smtp_in_auth(au, &s, &ss) == OK)
3329 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3330 else
3331 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3332 break;
3333 }
3334 }
3335 #endif
3336
3337 switch(smtp_read_command(TRUE))
3338 {
3339 /* The AUTH command is not permitted to occur inside a transaction, and may
3340 occur successfully only once per connection. Actually, that isn't quite
3341 true. When TLS is started, all previous information about a connection must
3342 be discarded, so a new AUTH is permitted at that time.
3343
3344 AUTH may only be used when it has been advertised. However, it seems that
3345 there are clients that send AUTH when it hasn't been advertised, some of
3346 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3347 So there's a get-out that allows this to happen.
3348
3349 AUTH is initially labelled as a "nonmail command" so that one occurrence
3350 doesn't get counted. We change the label here so that multiple failing
3351 AUTHS will eventually hit the nonmail threshold. */
3352
3353 case AUTH_CMD:
3354 HAD(SCH_AUTH);
3355 authentication_failed = TRUE;
3356 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3357
3358 if (!auth_advertised && !allow_auth_unadvertised)
3359 {
3360 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3361 US"AUTH command used when not advertised");
3362 break;
3363 }
3364 if (sender_host_authenticated)
3365 {
3366 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3367 US"already authenticated");
3368 break;
3369 }
3370 if (sender_address)
3371 {
3372 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3373 US"not permitted in mail transaction");
3374 break;
3375 }
3376
3377 /* Check the ACL */
3378
3379 if ( acl_smtp_auth
3380 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3381 &user_msg, &log_msg)) != OK
3382 )
3383 {
3384 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3385 break;
3386 }
3387
3388 /* Find the name of the requested authentication mechanism. */
3389
3390 s = smtp_cmd_data;
3391 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3392 {
3393 if (!isalnum(c) && c != '-' && c != '_')
3394 {
3395 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3396 US"invalid character in authentication mechanism name");
3397 goto COMMAND_LOOP;
3398 }
3399 smtp_cmd_data++;
3400 }
3401
3402 /* If not at the end of the line, we must be at white space. Terminate the
3403 name and move the pointer on to any data that may be present. */
3404
3405 if (*smtp_cmd_data != 0)
3406 {
3407 *smtp_cmd_data++ = 0;
3408 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3409 }
3410
3411 /* Search for an authentication mechanism which is configured for use
3412 as a server and which has been advertised (unless, sigh, allow_auth_
3413 unadvertised is set). */
3414
3415 for (au = auths; au; au = au->next)
3416 if (strcmpic(s, au->public_name) == 0 && au->server &&
3417 (au->advertised || allow_auth_unadvertised))
3418 break;
3419
3420 if (au)
3421 {
3422 c = smtp_in_auth(au, &s, &ss);
3423
3424 smtp_printf("%s\r\n", s);
3425 if (c != OK)
3426 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3427 au->name, host_and_ident(FALSE), ss);
3428 }
3429 else
3430 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3431 string_sprintf("%s authentication mechanism not supported", s));
3432
3433 break; /* AUTH_CMD */
3434
3435 /* The HELO/EHLO commands are permitted to appear in the middle of a
3436 session as well as at the beginning. They have the effect of a reset in
3437 addition to their other functions. Their absence at the start cannot be
3438 taken to be an error.
3439
3440 RFC 2821 says:
3441
3442 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3443 or 502 failure replies MUST be returned as appropriate. The SMTP
3444 server MUST stay in the same state after transmitting these replies
3445 that it was in before the EHLO was received.
3446
3447 Therefore, we do not do the reset until after checking the command for
3448 acceptability. This change was made for Exim release 4.11. Previously
3449 it did the reset first. */
3450
3451 case HELO_CMD:
3452 HAD(SCH_HELO);
3453 hello = US"HELO";
3454 esmtp = FALSE;
3455 goto HELO_EHLO;
3456
3457 case EHLO_CMD:
3458 HAD(SCH_EHLO);
3459 hello = US"EHLO";
3460 esmtp = TRUE;
3461
3462 HELO_EHLO: /* Common code for HELO and EHLO */
3463 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3464 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3465
3466 /* Reject the HELO if its argument was invalid or non-existent. A
3467 successful check causes the argument to be saved in malloc store. */
3468
3469 if (!check_helo(smtp_cmd_data))
3470 {
3471 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3472
3473 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3474 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3475 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3476 string_printing(smtp_cmd_argument));
3477
3478 if (++synprot_error_count > smtp_max_synprot_errors)
3479 {
3480 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3481 "syntax or protocol errors (last command was \"%s\")",
3482 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3483 done = 1;
3484 }
3485
3486 break;
3487 }
3488
3489 /* If sender_host_unknown is true, we have got here via the -bs interface,
3490 not called from inetd. Otherwise, we are running an IP connection and the
3491 host address will be set. If the helo name is the primary name of this
3492 host and we haven't done a reverse lookup, force one now. If helo_required
3493 is set, ensure that the HELO name matches the actual host. If helo_verify
3494 is set, do the same check, but softly. */
3495
3496 if (!sender_host_unknown)
3497 {
3498 BOOL old_helo_verified = helo_verified;
3499 uschar *p = smtp_cmd_data;
3500
3501 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3502 *p = 0;
3503
3504 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3505 because otherwise the log can be confusing. */
3506
3507 if (sender_host_name == NULL &&