Merge branch 'SMTPUTF8_1516'. Bug 1516
[exim.git] / src / src / smtp_in.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2014 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8 /* Functions for handling an incoming SMTP call. */
9
10
11 #include "exim.h"
12
13
14 /* Initialize for TCP wrappers if so configured. It appears that the macro
15 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
16 including that header, and restore its value afterwards. */
17
18 #ifdef USE_TCP_WRAPPERS
19
20 #if HAVE_IPV6
21 #define EXIM_HAVE_IPV6
22 #endif
23 #undef HAVE_IPV6
24 #include <tcpd.h>
25 #undef HAVE_IPV6
26 #ifdef EXIM_HAVE_IPV6
27 #define HAVE_IPV6 TRUE
28 #endif
29
30 int allow_severity = LOG_INFO;
31 int deny_severity = LOG_NOTICE;
32 uschar *tcp_wrappers_name;
33 #endif
34
35
36 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
37 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
38 commands that accept arguments, and this in particular applies to AUTH, where
39 the data can be quite long. More recently this value was 2048 in Exim;
40 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
41 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
42 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
43 we need room to handle large base64-encoded AUTHs for GSSAPI.
44 */
45
46 #define smtp_cmd_buffer_size 16384
47
48 /* Size of buffer for reading SMTP incoming packets */
49
50 #define in_buffer_size 8192
51
52 /* Structure for SMTP command list */
53
54 typedef struct {
55 const char *name;
56 int len;
57 short int cmd;
58 short int has_arg;
59 short int is_mail_cmd;
60 } smtp_cmd_list;
61
62 /* Codes for identifying commands. We order them so that those that come first
63 are those for which synchronization is always required. Checking this can help
64 block some spam. */
65
66 enum {
67 /* These commands are required to be synchronized, i.e. to be the last in a
68 block of commands when pipelining. */
69
70 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
71 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
72 ETRN_CMD, /* This by analogy with TURN from the RFC */
73 STARTTLS_CMD, /* Required by the STARTTLS RFC */
74
75 /* This is a dummy to identify the non-sync commands when pipelining */
76
77 NON_SYNC_CMD_PIPELINING,
78
79 /* These commands need not be synchronized when pipelining */
80
81 MAIL_CMD, RCPT_CMD, RSET_CMD,
82
83 /* This is a dummy to identify the non-sync commands when not pipelining */
84
85 NON_SYNC_CMD_NON_PIPELINING,
86
87 /* I have been unable to find a statement about the use of pipelining
88 with AUTH, so to be on the safe side it is here, though I kind of feel
89 it should be up there with the synchronized commands. */
90
91 AUTH_CMD,
92
93 /* I'm not sure about these, but I don't think they matter. */
94
95 QUIT_CMD, HELP_CMD,
96
97 #ifdef EXPERIMENTAL_PROXY
98 PROXY_FAIL_IGNORE_CMD,
99 #endif
100
101 /* These are specials that don't correspond to actual commands */
102
103 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
104 TOO_MANY_NONMAIL_CMD };
105
106
107 /* This is a convenience macro for adding the identity of an SMTP command
108 to the circular buffer that holds a list of the last n received. */
109
110 #define HAD(n) \
111 smtp_connection_had[smtp_ch_index++] = n; \
112 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
113
114
115 /*************************************************
116 * Local static variables *
117 *************************************************/
118
119 static auth_instance *authenticated_by;
120 static BOOL auth_advertised;
121 #ifdef SUPPORT_TLS
122 static BOOL tls_advertised;
123 #endif
124 static BOOL dsn_advertised;
125 static BOOL esmtp;
126 static BOOL helo_required = FALSE;
127 static BOOL helo_verify = FALSE;
128 static BOOL helo_seen;
129 static BOOL helo_accept_junk;
130 static BOOL count_nonmail;
131 static BOOL pipelining_advertised;
132 static BOOL rcpt_smtp_response_same;
133 static BOOL rcpt_in_progress;
134 static int nonmail_command_count;
135 static BOOL smtp_exit_function_called = 0;
136 #ifdef EXPERIMENTAL_INTERNATIONAL
137 static BOOL smtputf8_advertised;
138 #endif
139 static int synprot_error_count;
140 static int unknown_command_count;
141 static int sync_cmd_limit;
142 static int smtp_write_error = 0;
143
144 static uschar *rcpt_smtp_response;
145 static uschar *smtp_data_buffer;
146 static uschar *smtp_cmd_data;
147
148 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
149 final fields of all except AUTH are forced TRUE at the start of a new message
150 setup, to allow one of each between messages that is not counted as a nonmail
151 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
152 allow a new EHLO after starting up TLS.
153
154 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
155 counted. However, the flag is changed when AUTH is received, so that multiple
156 failing AUTHs will eventually hit the limit. After a successful AUTH, another
157 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
158 forced TRUE, to allow for the re-authentication that can happen at that point.
159
160 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
161 count of non-mail commands and possibly provoke an error. */
162
163 static smtp_cmd_list cmd_list[] = {
164 /* name len cmd has_arg is_mail_cmd */
165
166 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
167 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
168 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
169 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
170 #ifdef SUPPORT_TLS
171 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
172 #endif
173
174 /* If you change anything above here, also fix the definitions below. */
175
176 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
177 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
178 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
179 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
180 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
181 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
182 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
183 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
184 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
185 };
186
187 static smtp_cmd_list *cmd_list_end =
188 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
189
190 #define CMD_LIST_RSET 0
191 #define CMD_LIST_HELO 1
192 #define CMD_LIST_EHLO 2
193 #define CMD_LIST_AUTH 3
194 #define CMD_LIST_STARTTLS 4
195
196 /* This list of names is used for performing the smtp_no_mail logging action.
197 It must be kept in step with the SCH_xxx enumerations. */
198
199 static uschar *smtp_names[] =
200 {
201 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
202 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
203 US"VRFY" };
204
205 static uschar *protocols_local[] = {
206 US"local-smtp", /* HELO */
207 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
208 US"local-esmtp", /* EHLO */
209 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
210 US"local-esmtpa", /* EHLO->AUTH */
211 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
212 };
213 static uschar *protocols[] = {
214 US"smtp", /* HELO */
215 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
216 US"esmtp", /* EHLO */
217 US"esmtps", /* EHLO->STARTTLS->EHLO */
218 US"esmtpa", /* EHLO->AUTH */
219 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
220 };
221
222 #define pnormal 0
223 #define pextend 2
224 #define pcrpted 1 /* added to pextend or pnormal */
225 #define pauthed 2 /* added to pextend */
226
227 /* Sanity check and validate optional args to MAIL FROM: envelope */
228 enum {
229 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
230 #ifndef DISABLE_PRDR
231 ENV_MAIL_OPT_PRDR,
232 #endif
233 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
234 #ifdef EXPERIMENTAL_INTERNATIONAL
235 ENV_MAIL_OPT_UTF8,
236 #endif
237 ENV_MAIL_OPT_NULL
238 };
239 typedef struct {
240 uschar * name; /* option requested during MAIL cmd */
241 int value; /* enum type */
242 BOOL need_value; /* TRUE requires value (name=value pair format)
243 FALSE is a singleton */
244 } env_mail_type_t;
245 static env_mail_type_t env_mail_type_list[] = {
246 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
247 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
248 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
249 #ifndef DISABLE_PRDR
250 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
251 #endif
252 { US"RET", ENV_MAIL_OPT_RET, TRUE },
253 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
254 #ifdef EXPERIMENTAL_INTERNATIONAL
255 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
256 #endif
257 { US"NULL", ENV_MAIL_OPT_NULL, FALSE }
258 };
259
260 /* When reading SMTP from a remote host, we have to use our own versions of the
261 C input-reading functions, in order to be able to flush the SMTP output only
262 when about to read more data from the socket. This is the only way to get
263 optimal performance when the client is using pipelining. Flushing for every
264 command causes a separate packet and reply packet each time; saving all the
265 responses up (when pipelining) combines them into one packet and one response.
266
267 For simplicity, these functions are used for *all* SMTP input, not only when
268 receiving over a socket. However, after setting up a secure socket (SSL), input
269 is read via the OpenSSL library, and another set of functions is used instead
270 (see tls.c).
271
272 These functions are set in the receive_getc etc. variables and called with the
273 same interface as the C functions. However, since there can only ever be
274 one incoming SMTP call, we just use a single buffer and flags. There is no need
275 to implement a complicated private FILE-like structure.*/
276
277 static uschar *smtp_inbuffer;
278 static uschar *smtp_inptr;
279 static uschar *smtp_inend;
280 static int smtp_had_eof;
281 static int smtp_had_error;
282
283
284 /*************************************************
285 * SMTP version of getc() *
286 *************************************************/
287
288 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
289 it flushes the output, and refills the buffer, with a timeout. The signal
290 handler is set appropriately by the calling function. This function is not used
291 after a connection has negotated itself into an TLS/SSL state.
292
293 Arguments: none
294 Returns: the next character or EOF
295 */
296
297 int
298 smtp_getc(void)
299 {
300 if (smtp_inptr >= smtp_inend)
301 {
302 int rc, save_errno;
303 fflush(smtp_out);
304 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
305 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
306 save_errno = errno;
307 alarm(0);
308 if (rc <= 0)
309 {
310 /* Must put the error text in fixed store, because this might be during
311 header reading, where it releases unused store above the header. */
312 if (rc < 0)
313 {
314 smtp_had_error = save_errno;
315 smtp_read_error = string_copy_malloc(
316 string_sprintf(" (error: %s)", strerror(save_errno)));
317 }
318 else smtp_had_eof = 1;
319 return EOF;
320 }
321 #ifndef DISABLE_DKIM
322 dkim_exim_verify_feed(smtp_inbuffer, rc);
323 #endif
324 smtp_inend = smtp_inbuffer + rc;
325 smtp_inptr = smtp_inbuffer;
326 }
327 return *smtp_inptr++;
328 }
329
330
331
332 /*************************************************
333 * SMTP version of ungetc() *
334 *************************************************/
335
336 /* Puts a character back in the input buffer. Only ever
337 called once.
338
339 Arguments:
340 ch the character
341
342 Returns: the character
343 */
344
345 int
346 smtp_ungetc(int ch)
347 {
348 *(--smtp_inptr) = ch;
349 return ch;
350 }
351
352
353
354
355 /*************************************************
356 * SMTP version of feof() *
357 *************************************************/
358
359 /* Tests for a previous EOF
360
361 Arguments: none
362 Returns: non-zero if the eof flag is set
363 */
364
365 int
366 smtp_feof(void)
367 {
368 return smtp_had_eof;
369 }
370
371
372
373
374 /*************************************************
375 * SMTP version of ferror() *
376 *************************************************/
377
378 /* Tests for a previous read error, and returns with errno
379 restored to what it was when the error was detected.
380
381 Arguments: none
382 Returns: non-zero if the error flag is set
383 */
384
385 int
386 smtp_ferror(void)
387 {
388 errno = smtp_had_error;
389 return smtp_had_error;
390 }
391
392
393
394 /*************************************************
395 * Test for characters in the SMTP buffer *
396 *************************************************/
397
398 /* Used at the end of a message
399
400 Arguments: none
401 Returns: TRUE/FALSE
402 */
403
404 BOOL
405 smtp_buffered(void)
406 {
407 return smtp_inptr < smtp_inend;
408 }
409
410
411
412 /*************************************************
413 * Write formatted string to SMTP channel *
414 *************************************************/
415
416 /* This is a separate function so that we don't have to repeat everything for
417 TLS support or debugging. It is global so that the daemon and the
418 authentication functions can use it. It does not return any error indication,
419 because major problems such as dropped connections won't show up till an output
420 flush for non-TLS connections. The smtp_fflush() function is available for
421 checking that: for convenience, TLS output errors are remembered here so that
422 they are also picked up later by smtp_fflush().
423
424 Arguments:
425 format format string
426 ... optional arguments
427
428 Returns: nothing
429 */
430
431 void
432 smtp_printf(const char *format, ...)
433 {
434 va_list ap;
435
436 va_start(ap, format);
437 smtp_vprintf(format, ap);
438 va_end(ap);
439 }
440
441 /* This is split off so that verify.c:respond_printf() can, in effect, call
442 smtp_printf(), bearing in mind that in C a vararg function can't directly
443 call another vararg function, only a function which accepts a va_list. */
444
445 void
446 smtp_vprintf(const char *format, va_list ap)
447 {
448 BOOL yield;
449
450 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
451
452 DEBUG(D_receive)
453 {
454 void *reset_point = store_get(0);
455 uschar *msg_copy, *cr, *end;
456 msg_copy = string_copy(big_buffer);
457 end = msg_copy + Ustrlen(msg_copy);
458 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
459 memmove(cr, cr + 1, (end--) - cr);
460 debug_printf("SMTP>> %s", msg_copy);
461 store_reset(reset_point);
462 }
463
464 if (!yield)
465 {
466 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
467 smtp_closedown(US"Unexpected error");
468 exim_exit(EXIT_FAILURE);
469 }
470
471 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
472 have had the same. Note: this code is also present in smtp_respond(). It would
473 be tidier to have it only in one place, but when it was added, it was easier to
474 do it that way, so as not to have to mess with the code for the RCPT command,
475 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
476
477 if (rcpt_in_progress)
478 {
479 if (rcpt_smtp_response == NULL)
480 rcpt_smtp_response = string_copy(big_buffer);
481 else if (rcpt_smtp_response_same &&
482 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
483 rcpt_smtp_response_same = FALSE;
484 rcpt_in_progress = FALSE;
485 }
486
487 /* Now write the string */
488
489 #ifdef SUPPORT_TLS
490 if (tls_in.active >= 0)
491 {
492 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
493 smtp_write_error = -1;
494 }
495 else
496 #endif
497
498 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
499 }
500
501
502
503 /*************************************************
504 * Flush SMTP out and check for error *
505 *************************************************/
506
507 /* This function isn't currently used within Exim (it detects errors when it
508 tries to read the next SMTP input), but is available for use in local_scan().
509 For non-TLS connections, it flushes the output and checks for errors. For
510 TLS-connections, it checks for a previously-detected TLS write error.
511
512 Arguments: none
513 Returns: 0 for no error; -1 after an error
514 */
515
516 int
517 smtp_fflush(void)
518 {
519 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
520 return smtp_write_error;
521 }
522
523
524
525 /*************************************************
526 * SMTP command read timeout *
527 *************************************************/
528
529 /* Signal handler for timing out incoming SMTP commands. This attempts to
530 finish off tidily.
531
532 Argument: signal number (SIGALRM)
533 Returns: nothing
534 */
535
536 static void
537 command_timeout_handler(int sig)
538 {
539 sig = sig; /* Keep picky compilers happy */
540 log_write(L_lost_incoming_connection,
541 LOG_MAIN, "SMTP command timeout on%s connection from %s",
542 (tls_in.active >= 0)? " TLS" : "",
543 host_and_ident(FALSE));
544 if (smtp_batched_input)
545 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
546 smtp_notquit_exit(US"command-timeout", US"421",
547 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
548 exim_exit(EXIT_FAILURE);
549 }
550
551
552
553 /*************************************************
554 * SIGTERM received *
555 *************************************************/
556
557 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
558
559 Argument: signal number (SIGTERM)
560 Returns: nothing
561 */
562
563 static void
564 command_sigterm_handler(int sig)
565 {
566 sig = sig; /* Keep picky compilers happy */
567 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
568 if (smtp_batched_input)
569 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
570 smtp_notquit_exit(US"signal-exit", US"421",
571 US"%s: Service not available - closing connection", smtp_active_hostname);
572 exim_exit(EXIT_FAILURE);
573 }
574
575
576
577
578 #ifdef EXPERIMENTAL_PROXY
579 /*************************************************
580 * Restore socket timeout to previous value *
581 *************************************************/
582 /* If the previous value was successfully retrieved, restore
583 it before returning control to the non-proxy routines
584
585 Arguments: fd - File descriptor for input
586 get_ok - Successfully retrieved previous values
587 tvtmp - Time struct with previous values
588 vslen - Length of time struct
589 Returns: none
590 */
591 static void
592 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
593 {
594 if (get_ok == 0)
595 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
596 }
597
598 /*************************************************
599 * Check if host is required proxy host *
600 *************************************************/
601 /* The function determines if inbound host will be a regular smtp host
602 or if it is configured that it must use Proxy Protocol.
603
604 Arguments: none
605 Returns: bool
606 */
607
608 static BOOL
609 check_proxy_protocol_host()
610 {
611 int rc;
612 /* Cannot configure local connection as a proxy inbound */
613 if (sender_host_address == NULL) return proxy_session;
614
615 rc = verify_check_this_host(&proxy_required_hosts, NULL, NULL,
616 sender_host_address, NULL);
617 if (rc == OK)
618 {
619 DEBUG(D_receive)
620 debug_printf("Detected proxy protocol configured host\n");
621 proxy_session = TRUE;
622 }
623 return proxy_session;
624 }
625
626
627 /*************************************************
628 * Setup host for proxy protocol *
629 *************************************************/
630 /* The function configures the connection based on a header from the
631 inbound host to use Proxy Protocol. The specification is very exact
632 so exit with an error if do not find the exact required pieces. This
633 includes an incorrect number of spaces separating args.
634
635 Arguments: none
636 Returns: int
637 */
638
639 static BOOL
640 setup_proxy_protocol_host()
641 {
642 union {
643 struct {
644 uschar line[108];
645 } v1;
646 struct {
647 uschar sig[12];
648 uint8_t ver_cmd;
649 uint8_t fam;
650 uint16_t len;
651 union {
652 struct { /* TCP/UDP over IPv4, len = 12 */
653 uint32_t src_addr;
654 uint32_t dst_addr;
655 uint16_t src_port;
656 uint16_t dst_port;
657 } ip4;
658 struct { /* TCP/UDP over IPv6, len = 36 */
659 uint8_t src_addr[16];
660 uint8_t dst_addr[16];
661 uint16_t src_port;
662 uint16_t dst_port;
663 } ip6;
664 struct { /* AF_UNIX sockets, len = 216 */
665 uschar src_addr[108];
666 uschar dst_addr[108];
667 } unx;
668 } addr;
669 } v2;
670 } hdr;
671
672 /* Temp variables used in PPv2 address:port parsing */
673 uint16_t tmpport;
674 char tmpip[INET_ADDRSTRLEN];
675 struct sockaddr_in tmpaddr;
676 char tmpip6[INET6_ADDRSTRLEN];
677 struct sockaddr_in6 tmpaddr6;
678
679 int get_ok = 0;
680 int size, ret, fd;
681 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
682 uschar *iptype; /* To display debug info */
683 struct timeval tv;
684 socklen_t vslen = 0;
685 struct timeval tvtmp;
686
687 vslen = sizeof(struct timeval);
688
689 fd = fileno(smtp_in);
690
691 /* Save current socket timeout values */
692 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
693 &vslen);
694
695 /* Proxy Protocol host must send header within a short time
696 (default 3 seconds) or it's considered invalid */
697 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
698 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
699 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
700 sizeof(struct timeval));
701
702 do
703 {
704 /* The inbound host was declared to be a Proxy Protocol host, so
705 don't do a PEEK into the data, actually slurp it up. */
706 ret = recv(fd, &hdr, sizeof(hdr), 0);
707 }
708 while (ret == -1 && errno == EINTR);
709
710 if (ret == -1)
711 {
712 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
713 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
714 }
715
716 if (ret >= 16 &&
717 memcmp(&hdr.v2, v2sig, 12) == 0)
718 {
719 uint8_t ver, cmd;
720
721 /* May 2014: haproxy combined the version and command into one byte to
722 allow two full bytes for the length field in order to proxy SSL
723 connections. SSL Proxy is not supported in this version of Exim, but
724 must still seperate values here. */
725 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
726 cmd = (hdr.v2.ver_cmd & 0x0f);
727
728 if (ver != 0x02)
729 {
730 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
731 goto proxyfail;
732 }
733 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
734 /* The v2 header will always be 16 bytes per the spec. */
735 size = 16 + hdr.v2.len;
736 if (ret < size)
737 {
738 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
739 ret, size);
740 goto proxyfail;
741 }
742 switch (cmd)
743 {
744 case 0x01: /* PROXY command */
745 switch (hdr.v2.fam)
746 {
747 case 0x11: /* TCPv4 address type */
748 iptype = US"IPv4";
749 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
750 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
751 if (!string_is_ip_address(US tmpip,NULL))
752 {
753 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
754 return ERRNO_PROXYFAIL;
755 }
756 proxy_host_address = sender_host_address;
757 sender_host_address = string_copy(US tmpip);
758 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
759 proxy_host_port = sender_host_port;
760 sender_host_port = tmpport;
761 /* Save dest ip/port */
762 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
763 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
764 if (!string_is_ip_address(US tmpip,NULL))
765 {
766 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
767 return ERRNO_PROXYFAIL;
768 }
769 proxy_target_address = string_copy(US tmpip);
770 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
771 proxy_target_port = tmpport;
772 goto done;
773 case 0x21: /* TCPv6 address type */
774 iptype = US"IPv6";
775 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
776 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
777 if (!string_is_ip_address(US tmpip6,NULL))
778 {
779 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
780 return ERRNO_PROXYFAIL;
781 }
782 proxy_host_address = sender_host_address;
783 sender_host_address = string_copy(US tmpip6);
784 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
785 proxy_host_port = sender_host_port;
786 sender_host_port = tmpport;
787 /* Save dest ip/port */
788 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
789 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
790 if (!string_is_ip_address(US tmpip6,NULL))
791 {
792 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
793 return ERRNO_PROXYFAIL;
794 }
795 proxy_target_address = string_copy(US tmpip6);
796 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
797 proxy_target_port = tmpport;
798 goto done;
799 default:
800 DEBUG(D_receive)
801 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
802 hdr.v2.fam);
803 goto proxyfail;
804 }
805 /* Unsupported protocol, keep local connection address */
806 break;
807 case 0x00: /* LOCAL command */
808 /* Keep local connection address for LOCAL */
809 break;
810 default:
811 DEBUG(D_receive)
812 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
813 goto proxyfail;
814 }
815 }
816 else if (ret >= 8 &&
817 memcmp(hdr.v1.line, "PROXY", 5) == 0)
818 {
819 uschar *p = string_copy(hdr.v1.line);
820 uschar *end = memchr(p, '\r', ret - 1);
821 uschar *sp; /* Utility variables follow */
822 int tmp_port;
823 char *endc;
824
825 if (!end || end[1] != '\n')
826 {
827 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
828 goto proxyfail;
829 }
830 *end = '\0'; /* Terminate the string */
831 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
832 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
833 /* Step through the string looking for the required fields. Ensure
834 strict adherance to required formatting, exit for any error. */
835 p += 5;
836 if (!isspace(*(p++)))
837 {
838 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
839 goto proxyfail;
840 }
841 if (!Ustrncmp(p, CCS"TCP4", 4))
842 iptype = US"IPv4";
843 else if (!Ustrncmp(p,CCS"TCP6", 4))
844 iptype = US"IPv6";
845 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
846 {
847 iptype = US"Unknown";
848 goto done;
849 }
850 else
851 {
852 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
853 goto proxyfail;
854 }
855
856 p += Ustrlen(iptype);
857 if (!isspace(*(p++)))
858 {
859 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
860 goto proxyfail;
861 }
862 /* Find the end of the arg */
863 if ((sp = Ustrchr(p, ' ')) == NULL)
864 {
865 DEBUG(D_receive)
866 debug_printf("Did not find proxied src %s\n", iptype);
867 goto proxyfail;
868 }
869 *sp = '\0';
870 if(!string_is_ip_address(p,NULL))
871 {
872 DEBUG(D_receive)
873 debug_printf("Proxied src arg is not an %s address\n", iptype);
874 goto proxyfail;
875 }
876 proxy_host_address = sender_host_address;
877 sender_host_address = p;
878 p = sp + 1;
879 if ((sp = Ustrchr(p, ' ')) == NULL)
880 {
881 DEBUG(D_receive)
882 debug_printf("Did not find proxy dest %s\n", iptype);
883 goto proxyfail;
884 }
885 *sp = '\0';
886 if(!string_is_ip_address(p,NULL))
887 {
888 DEBUG(D_receive)
889 debug_printf("Proxy dest arg is not an %s address\n", iptype);
890 goto proxyfail;
891 }
892 proxy_target_address = p;
893 p = sp + 1;
894 if ((sp = Ustrchr(p, ' ')) == NULL)
895 {
896 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
897 goto proxyfail;
898 }
899 *sp = '\0';
900 tmp_port = strtol(CCS p,&endc,10);
901 if (*endc || tmp_port == 0)
902 {
903 DEBUG(D_receive)
904 debug_printf("Proxied src port '%s' not an integer\n", p);
905 goto proxyfail;
906 }
907 proxy_host_port = sender_host_port;
908 sender_host_port = tmp_port;
909 p = sp + 1;
910 if ((sp = Ustrchr(p, '\0')) == NULL)
911 {
912 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
913 goto proxyfail;
914 }
915 tmp_port = strtol(CCS p,&endc,10);
916 if (*endc || tmp_port == 0)
917 {
918 DEBUG(D_receive)
919 debug_printf("Proxy dest port '%s' not an integer\n", p);
920 goto proxyfail;
921 }
922 proxy_target_port = tmp_port;
923 /* Already checked for /r /n above. Good V1 header received. */
924 goto done;
925 }
926 else
927 {
928 /* Wrong protocol */
929 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
930 goto proxyfail;
931 }
932
933 proxyfail:
934 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
935 /* Don't flush any potential buffer contents. Any input should cause a
936 synchronization failure */
937 return FALSE;
938
939 done:
940 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
941 DEBUG(D_receive)
942 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
943 return proxy_session;
944 }
945 #endif
946
947 /*************************************************
948 * Read one command line *
949 *************************************************/
950
951 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
952 There are sites that don't do this, and in any case internal SMTP probably
953 should check only for LF. Consequently, we check here for LF only. The line
954 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
955 an unknown command. The command is read into the global smtp_cmd_buffer so that
956 it is available via $smtp_command.
957
958 The character reading routine sets up a timeout for each block actually read
959 from the input (which may contain more than one command). We set up a special
960 signal handler that closes down the session on a timeout. Control does not
961 return when it runs.
962
963 Arguments:
964 check_sync if TRUE, check synchronization rules if global option is TRUE
965
966 Returns: a code identifying the command (enumerated above)
967 */
968
969 static int
970 smtp_read_command(BOOL check_sync)
971 {
972 int c;
973 int ptr = 0;
974 smtp_cmd_list *p;
975 BOOL hadnull = FALSE;
976
977 os_non_restarting_signal(SIGALRM, command_timeout_handler);
978
979 while ((c = (receive_getc)()) != '\n' && c != EOF)
980 {
981 if (ptr >= smtp_cmd_buffer_size)
982 {
983 os_non_restarting_signal(SIGALRM, sigalrm_handler);
984 return OTHER_CMD;
985 }
986 if (c == 0)
987 {
988 hadnull = TRUE;
989 c = '?';
990 }
991 smtp_cmd_buffer[ptr++] = c;
992 }
993
994 receive_linecount++; /* For BSMTP errors */
995 os_non_restarting_signal(SIGALRM, sigalrm_handler);
996
997 /* If hit end of file, return pseudo EOF command. Whether we have a
998 part-line already read doesn't matter, since this is an error state. */
999
1000 if (c == EOF) return EOF_CMD;
1001
1002 /* Remove any CR and white space at the end of the line, and terminate the
1003 string. */
1004
1005 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1006 smtp_cmd_buffer[ptr] = 0;
1007
1008 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1009
1010 /* NULLs are not allowed in SMTP commands */
1011
1012 if (hadnull) return BADCHAR_CMD;
1013
1014 /* Scan command list and return identity, having set the data pointer
1015 to the start of the actual data characters. Check for SMTP synchronization
1016 if required. */
1017
1018 for (p = cmd_list; p < cmd_list_end; p++)
1019 {
1020 #ifdef EXPERIMENTAL_PROXY
1021 /* Only allow QUIT command if Proxy Protocol parsing failed */
1022 if (proxy_session && proxy_session_failed)
1023 {
1024 if (p->cmd != QUIT_CMD)
1025 continue;
1026 }
1027 #endif
1028 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
1029 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
1030 smtp_cmd_buffer[p->len] == 0 ||
1031 smtp_cmd_buffer[p->len] == ' '))
1032 {
1033 if (smtp_inptr < smtp_inend && /* Outstanding input */
1034 p->cmd < sync_cmd_limit && /* Command should sync */
1035 check_sync && /* Local flag set */
1036 smtp_enforce_sync && /* Global flag set */
1037 sender_host_address != NULL && /* Not local input */
1038 !sender_host_notsocket) /* Really is a socket */
1039 return BADSYN_CMD;
1040
1041 /* The variables $smtp_command and $smtp_command_argument point into the
1042 unmodified input buffer. A copy of the latter is taken for actual
1043 processing, so that it can be chopped up into separate parts if necessary,
1044 for example, when processing a MAIL command options such as SIZE that can
1045 follow the sender address. */
1046
1047 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1048 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1049 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1050 smtp_cmd_data = smtp_data_buffer;
1051
1052 /* Count non-mail commands from those hosts that are controlled in this
1053 way. The default is all hosts. We don't waste effort checking the list
1054 until we get a non-mail command, but then cache the result to save checking
1055 again. If there's a DEFER while checking the host, assume it's in the list.
1056
1057 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1058 start of each incoming message by fiddling with the value in the table. */
1059
1060 if (!p->is_mail_cmd)
1061 {
1062 if (count_nonmail == TRUE_UNSET) count_nonmail =
1063 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1064 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1065 return TOO_MANY_NONMAIL_CMD;
1066 }
1067
1068 /* If there is data for a command that does not expect it, generate the
1069 error here. */
1070
1071 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1072 }
1073 }
1074
1075 #ifdef EXPERIMENTAL_PROXY
1076 /* Only allow QUIT command if Proxy Protocol parsing failed */
1077 if (proxy_session && proxy_session_failed)
1078 return PROXY_FAIL_IGNORE_CMD;
1079 #endif
1080
1081 /* Enforce synchronization for unknown commands */
1082
1083 if (smtp_inptr < smtp_inend && /* Outstanding input */
1084 check_sync && /* Local flag set */
1085 smtp_enforce_sync && /* Global flag set */
1086 sender_host_address != NULL && /* Not local input */
1087 !sender_host_notsocket) /* Really is a socket */
1088 return BADSYN_CMD;
1089
1090 return OTHER_CMD;
1091 }
1092
1093
1094
1095 /*************************************************
1096 * Recheck synchronization *
1097 *************************************************/
1098
1099 /* Synchronization checks can never be perfect because a packet may be on its
1100 way but not arrived when the check is done. Such checks can in any case only be
1101 done when TLS is not in use. Normally, the checks happen when commands are
1102 read: Exim ensures that there is no more input in the input buffer. In normal
1103 cases, the response to the command will be fast, and there is no further check.
1104
1105 However, for some commands an ACL is run, and that can include delays. In those
1106 cases, it is useful to do another check on the input just before sending the
1107 response. This also applies at the start of a connection. This function does
1108 that check by means of the select() function, as long as the facility is not
1109 disabled or inappropriate. A failure of select() is ignored.
1110
1111 When there is unwanted input, we read it so that it appears in the log of the
1112 error.
1113
1114 Arguments: none
1115 Returns: TRUE if all is well; FALSE if there is input pending
1116 */
1117
1118 static BOOL
1119 check_sync(void)
1120 {
1121 int fd, rc;
1122 fd_set fds;
1123 struct timeval tzero;
1124
1125 if (!smtp_enforce_sync || sender_host_address == NULL ||
1126 sender_host_notsocket || tls_in.active >= 0)
1127 return TRUE;
1128
1129 fd = fileno(smtp_in);
1130 FD_ZERO(&fds);
1131 FD_SET(fd, &fds);
1132 tzero.tv_sec = 0;
1133 tzero.tv_usec = 0;
1134 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1135
1136 if (rc <= 0) return TRUE; /* Not ready to read */
1137 rc = smtp_getc();
1138 if (rc < 0) return TRUE; /* End of file or error */
1139
1140 smtp_ungetc(rc);
1141 rc = smtp_inend - smtp_inptr;
1142 if (rc > 150) rc = 150;
1143 smtp_inptr[rc] = 0;
1144 return FALSE;
1145 }
1146
1147
1148
1149 /*************************************************
1150 * Forced closedown of call *
1151 *************************************************/
1152
1153 /* This function is called from log.c when Exim is dying because of a serious
1154 disaster, and also from some other places. If an incoming non-batched SMTP
1155 channel is open, it swallows the rest of the incoming message if in the DATA
1156 phase, sends the reply string, and gives an error to all subsequent commands
1157 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1158 smtp_in.
1159
1160 Arguments:
1161 message SMTP reply string to send, excluding the code
1162
1163 Returns: nothing
1164 */
1165
1166 void
1167 smtp_closedown(uschar *message)
1168 {
1169 if (smtp_in == NULL || smtp_batched_input) return;
1170 receive_swallow_smtp();
1171 smtp_printf("421 %s\r\n", message);
1172
1173 for (;;)
1174 {
1175 switch(smtp_read_command(FALSE))
1176 {
1177 case EOF_CMD:
1178 return;
1179
1180 case QUIT_CMD:
1181 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1182 mac_smtp_fflush();
1183 return;
1184
1185 case RSET_CMD:
1186 smtp_printf("250 Reset OK\r\n");
1187 break;
1188
1189 default:
1190 smtp_printf("421 %s\r\n", message);
1191 break;
1192 }
1193 }
1194 }
1195
1196
1197
1198
1199 /*************************************************
1200 * Set up connection info for logging *
1201 *************************************************/
1202
1203 /* This function is called when logging information about an SMTP connection.
1204 It sets up appropriate source information, depending on the type of connection.
1205 If sender_fullhost is NULL, we are at a very early stage of the connection;
1206 just use the IP address.
1207
1208 Argument: none
1209 Returns: a string describing the connection
1210 */
1211
1212 uschar *
1213 smtp_get_connection_info(void)
1214 {
1215 uschar *hostname = (sender_fullhost == NULL)?
1216 sender_host_address : sender_fullhost;
1217
1218 if (host_checking)
1219 return string_sprintf("SMTP connection from %s", hostname);
1220
1221 if (sender_host_unknown || sender_host_notsocket)
1222 return string_sprintf("SMTP connection from %s", sender_ident);
1223
1224 if (is_inetd)
1225 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1226
1227 if ((log_extra_selector & LX_incoming_interface) != 0 &&
1228 interface_address != NULL)
1229 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1230 interface_address, interface_port);
1231
1232 return string_sprintf("SMTP connection from %s", hostname);
1233 }
1234
1235
1236
1237 #ifdef SUPPORT_TLS
1238 /* Append TLS-related information to a log line
1239
1240 Arguments:
1241 s String under construction: allocated string to extend, or NULL
1242 sizep Pointer to current allocation size (update on return), or NULL
1243 ptrp Pointer to index for new entries in string (update on return), or NULL
1244
1245 Returns: Allocated string or NULL
1246 */
1247 static uschar *
1248 s_tlslog(uschar * s, int * sizep, int * ptrp)
1249 {
1250 int size = sizep ? *sizep : 0;
1251 int ptr = ptrp ? *ptrp : 0;
1252
1253 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_in.cipher != NULL)
1254 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1255 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
1256 tls_in.cipher != NULL)
1257 s = string_append(s, &size, &ptr, 2, US" CV=",
1258 tls_in.certificate_verified? "yes":"no");
1259 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_in.peerdn != NULL)
1260 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1261 string_printing(tls_in.peerdn), US"\"");
1262 if ((log_extra_selector & LX_tls_sni) != 0 && tls_in.sni != NULL)
1263 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1264 string_printing(tls_in.sni), US"\"");
1265
1266 if (s)
1267 {
1268 s[ptr] = '\0';
1269 if (sizep) *sizep = size;
1270 if (ptrp) *ptrp = ptr;
1271 }
1272 return s;
1273 }
1274 #endif
1275
1276 /*************************************************
1277 * Log lack of MAIL if so configured *
1278 *************************************************/
1279
1280 /* This function is called when an SMTP session ends. If the log selector
1281 smtp_no_mail is set, write a log line giving some details of what has happened
1282 in the SMTP session.
1283
1284 Arguments: none
1285 Returns: nothing
1286 */
1287
1288 void
1289 smtp_log_no_mail(void)
1290 {
1291 int size, ptr, i;
1292 uschar *s, *sep;
1293
1294 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
1295 return;
1296
1297 s = NULL;
1298 size = ptr = 0;
1299
1300 if (sender_host_authenticated != NULL)
1301 {
1302 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1303 if (authenticated_id != NULL)
1304 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1305 }
1306
1307 #ifdef SUPPORT_TLS
1308 s = s_tlslog(s, &size, &ptr);
1309 #endif
1310
1311 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1312 US" C=..." : US" C=";
1313 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1314 {
1315 if (smtp_connection_had[i] != SCH_NONE)
1316 {
1317 s = string_append(s, &size, &ptr, 2, sep,
1318 smtp_names[smtp_connection_had[i]]);
1319 sep = US",";
1320 }
1321 }
1322
1323 for (i = 0; i < smtp_ch_index; i++)
1324 {
1325 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1326 sep = US",";
1327 }
1328
1329 if (s != NULL) s[ptr] = 0; else s = US"";
1330 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1331 host_and_ident(FALSE),
1332 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1333 s);
1334 }
1335
1336
1337
1338 /*************************************************
1339 * Check HELO line and set sender_helo_name *
1340 *************************************************/
1341
1342 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1343 the domain name of the sending host, or an ip literal in square brackets. The
1344 arrgument is placed in sender_helo_name, which is in malloc store, because it
1345 must persist over multiple incoming messages. If helo_accept_junk is set, this
1346 host is permitted to send any old junk (needed for some broken hosts).
1347 Otherwise, helo_allow_chars can be used for rogue characters in general
1348 (typically people want to let in underscores).
1349
1350 Argument:
1351 s the data portion of the line (already past any white space)
1352
1353 Returns: TRUE or FALSE
1354 */
1355
1356 static BOOL
1357 check_helo(uschar *s)
1358 {
1359 uschar *start = s;
1360 uschar *end = s + Ustrlen(s);
1361 BOOL yield = helo_accept_junk;
1362
1363 /* Discard any previous helo name */
1364
1365 if (sender_helo_name != NULL)
1366 {
1367 store_free(sender_helo_name);
1368 sender_helo_name = NULL;
1369 }
1370
1371 /* Skip tests if junk is permitted. */
1372
1373 if (!yield)
1374 {
1375 /* Allow the new standard form for IPv6 address literals, namely,
1376 [IPv6:....], and because someone is bound to use it, allow an equivalent
1377 IPv4 form. Allow plain addresses as well. */
1378
1379 if (*s == '[')
1380 {
1381 if (end[-1] == ']')
1382 {
1383 end[-1] = 0;
1384 if (strncmpic(s, US"[IPv6:", 6) == 0)
1385 yield = (string_is_ip_address(s+6, NULL) == 6);
1386 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1387 yield = (string_is_ip_address(s+6, NULL) == 4);
1388 else
1389 yield = (string_is_ip_address(s+1, NULL) != 0);
1390 end[-1] = ']';
1391 }
1392 }
1393
1394 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1395 that have been configured (usually underscore - sigh). */
1396
1397 else if (*s != 0)
1398 {
1399 yield = TRUE;
1400 while (*s != 0)
1401 {
1402 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1403 Ustrchr(helo_allow_chars, *s) == NULL)
1404 {
1405 yield = FALSE;
1406 break;
1407 }
1408 s++;
1409 }
1410 }
1411 }
1412
1413 /* Save argument if OK */
1414
1415 if (yield) sender_helo_name = string_copy_malloc(start);
1416 return yield;
1417 }
1418
1419
1420
1421
1422
1423 /*************************************************
1424 * Extract SMTP command option *
1425 *************************************************/
1426
1427 /* This function picks the next option setting off the end of smtp_cmd_data. It
1428 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1429 things that can appear there.
1430
1431 Arguments:
1432 name point this at the name
1433 value point this at the data string
1434
1435 Returns: TRUE if found an option
1436 */
1437
1438 static BOOL
1439 extract_option(uschar **name, uschar **value)
1440 {
1441 uschar *n;
1442 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1443 while (isspace(*v)) v--;
1444 v[1] = 0;
1445 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1446
1447 n = v;
1448 if (*v == '=')
1449 {
1450 while(isalpha(n[-1])) n--;
1451 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1452 if (!isspace(n[-1])) return FALSE;
1453 n[-1] = 0;
1454 }
1455 else
1456 {
1457 n++;
1458 if (v == smtp_cmd_data) return FALSE;
1459 }
1460 *v++ = 0;
1461 *name = n;
1462 *value = v;
1463 return TRUE;
1464 }
1465
1466
1467
1468
1469
1470 /*************************************************
1471 * Reset for new message *
1472 *************************************************/
1473
1474 /* This function is called whenever the SMTP session is reset from
1475 within either of the setup functions.
1476
1477 Argument: the stacking pool storage reset point
1478 Returns: nothing
1479 */
1480
1481 static void
1482 smtp_reset(void *reset_point)
1483 {
1484 store_reset(reset_point);
1485 recipients_list = NULL;
1486 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1487 raw_recipients_count = recipients_count = recipients_list_max = 0;
1488 cancel_cutthrough_connection("smtp reset");
1489 message_linecount = 0;
1490 message_size = -1;
1491 acl_added_headers = NULL;
1492 acl_removed_headers = NULL;
1493 queue_only_policy = FALSE;
1494 rcpt_smtp_response = NULL;
1495 rcpt_smtp_response_same = TRUE;
1496 rcpt_in_progress = FALSE;
1497 deliver_freeze = FALSE; /* Can be set by ACL */
1498 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1499 fake_response = OK; /* Can be set by ACL */
1500 #ifdef WITH_CONTENT_SCAN
1501 no_mbox_unspool = FALSE; /* Can be set by ACL */
1502 #endif
1503 submission_mode = FALSE; /* Can be set by ACL */
1504 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1505 active_local_from_check = local_from_check; /* Can be set by ACL */
1506 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1507 sender_address = NULL;
1508 submission_name = NULL; /* Can be set by ACL */
1509 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1510 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1511 sender_verified_list = NULL; /* No senders verified */
1512 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1513 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1514
1515 prdr_requested = FALSE;
1516
1517 /* Reset the DSN flags */
1518 dsn_ret = 0;
1519 dsn_envid = NULL;
1520
1521 authenticated_sender = NULL;
1522 #ifdef EXPERIMENTAL_BRIGHTMAIL
1523 bmi_run = 0;
1524 bmi_verdicts = NULL;
1525 #endif
1526 #ifndef DISABLE_DKIM
1527 dkim_signers = NULL;
1528 dkim_disable_verify = FALSE;
1529 dkim_collect_input = FALSE;
1530 #endif
1531 #ifdef EXPERIMENTAL_SPF
1532 spf_header_comment = NULL;
1533 spf_received = NULL;
1534 spf_result = NULL;
1535 spf_smtp_comment = NULL;
1536 #endif
1537 #ifdef EXPERIMENTAL_INTERNATIONAL
1538 message_smtputf8 = FALSE;
1539 #endif
1540 body_linecount = body_zerocount = 0;
1541
1542 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1543 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1544 /* Note that ratelimiters_conn persists across resets. */
1545
1546 /* Reset message ACL variables */
1547
1548 acl_var_m = NULL;
1549
1550 /* The message body variables use malloc store. They may be set if this is
1551 not the first message in an SMTP session and the previous message caused them
1552 to be referenced in an ACL. */
1553
1554 if (message_body != NULL)
1555 {
1556 store_free(message_body);
1557 message_body = NULL;
1558 }
1559
1560 if (message_body_end != NULL)
1561 {
1562 store_free(message_body_end);
1563 message_body_end = NULL;
1564 }
1565
1566 /* Warning log messages are also saved in malloc store. They are saved to avoid
1567 repetition in the same message, but it seems right to repeat them for different
1568 messages. */
1569
1570 while (acl_warn_logged != NULL)
1571 {
1572 string_item *this = acl_warn_logged;
1573 acl_warn_logged = acl_warn_logged->next;
1574 store_free(this);
1575 }
1576 }
1577
1578
1579
1580
1581
1582 /*************************************************
1583 * Initialize for incoming batched SMTP message *
1584 *************************************************/
1585
1586 /* This function is called from smtp_setup_msg() in the case when
1587 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1588 of messages in one file with SMTP commands between them. All errors must be
1589 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1590 relevant. After an error on a sender, or an invalid recipient, the remainder
1591 of the message is skipped. The value of received_protocol is already set.
1592
1593 Argument: none
1594 Returns: > 0 message successfully started (reached DATA)
1595 = 0 QUIT read or end of file reached
1596 < 0 should not occur
1597 */
1598
1599 static int
1600 smtp_setup_batch_msg(void)
1601 {
1602 int done = 0;
1603 void *reset_point = store_get(0);
1604
1605 /* Save the line count at the start of each transaction - single commands
1606 like HELO and RSET count as whole transactions. */
1607
1608 bsmtp_transaction_linecount = receive_linecount;
1609
1610 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1611
1612 smtp_reset(reset_point); /* Reset for start of message */
1613
1614 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1615 value. The values are 2 larger than the required yield of the function. */
1616
1617 while (done <= 0)
1618 {
1619 uschar *errmess;
1620 uschar *recipient = NULL;
1621 int start, end, sender_domain, recipient_domain;
1622
1623 switch(smtp_read_command(FALSE))
1624 {
1625 /* The HELO/EHLO commands set sender_address_helo if they have
1626 valid data; otherwise they are ignored, except that they do
1627 a reset of the state. */
1628
1629 case HELO_CMD:
1630 case EHLO_CMD:
1631
1632 check_helo(smtp_cmd_data);
1633 /* Fall through */
1634
1635 case RSET_CMD:
1636 smtp_reset(reset_point);
1637 bsmtp_transaction_linecount = receive_linecount;
1638 break;
1639
1640
1641 /* The MAIL FROM command requires an address as an operand. All we
1642 do here is to parse it for syntactic correctness. The form "<>" is
1643 a special case which converts into an empty string. The start/end
1644 pointers in the original are not used further for this address, as
1645 it is the canonical extracted address which is all that is kept. */
1646
1647 case MAIL_CMD:
1648 if (sender_address != NULL)
1649 /* The function moan_smtp_batch() does not return. */
1650 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1651
1652 if (smtp_cmd_data[0] == 0)
1653 /* The function moan_smtp_batch() does not return. */
1654 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1655
1656 /* Reset to start of message */
1657
1658 smtp_reset(reset_point);
1659
1660 /* Apply SMTP rewrite */
1661
1662 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1663 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1664 US"", global_rewrite_rules) : smtp_cmd_data;
1665
1666 /* Extract the address; the TRUE flag allows <> as valid */
1667
1668 raw_sender =
1669 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1670 TRUE);
1671
1672 if (raw_sender == NULL)
1673 /* The function moan_smtp_batch() does not return. */
1674 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1675
1676 sender_address = string_copy(raw_sender);
1677
1678 /* Qualify unqualified sender addresses if permitted to do so. */
1679
1680 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1681 {
1682 if (allow_unqualified_sender)
1683 {
1684 sender_address = rewrite_address_qualify(sender_address, FALSE);
1685 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1686 "and rewritten\n", raw_sender);
1687 }
1688 /* The function moan_smtp_batch() does not return. */
1689 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1690 "a domain");
1691 }
1692 break;
1693
1694
1695 /* The RCPT TO command requires an address as an operand. All we do
1696 here is to parse it for syntactic correctness. There may be any number
1697 of RCPT TO commands, specifying multiple senders. We build them all into
1698 a data structure that is in argc/argv format. The start/end values
1699 given by parse_extract_address are not used, as we keep only the
1700 extracted address. */
1701
1702 case RCPT_CMD:
1703 if (sender_address == NULL)
1704 /* The function moan_smtp_batch() does not return. */
1705 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1706
1707 if (smtp_cmd_data[0] == 0)
1708 /* The function moan_smtp_batch() does not return. */
1709 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1710
1711 /* Check maximum number allowed */
1712
1713 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1714 /* The function moan_smtp_batch() does not return. */
1715 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1716 recipients_max_reject? "552": "452");
1717
1718 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1719 recipient address */
1720
1721 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1722 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1723 global_rewrite_rules) : smtp_cmd_data;
1724
1725 /* rfc821_domains = TRUE; << no longer needed */
1726 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1727 &recipient_domain, FALSE);
1728 /* rfc821_domains = FALSE; << no longer needed */
1729
1730 if (recipient == NULL)
1731 /* The function moan_smtp_batch() does not return. */
1732 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1733
1734 /* If the recipient address is unqualified, qualify it if permitted. Then
1735 add it to the list of recipients. */
1736
1737 if (recipient_domain == 0)
1738 {
1739 if (allow_unqualified_recipient)
1740 {
1741 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1742 recipient);
1743 recipient = rewrite_address_qualify(recipient, TRUE);
1744 }
1745 /* The function moan_smtp_batch() does not return. */
1746 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1747 "a domain");
1748 }
1749 receive_add_recipient(recipient, -1);
1750 break;
1751
1752
1753 /* The DATA command is legal only if it follows successful MAIL FROM
1754 and RCPT TO commands. This function is complete when a valid DATA
1755 command is encountered. */
1756
1757 case DATA_CMD:
1758 if (sender_address == NULL || recipients_count <= 0)
1759 {
1760 /* The function moan_smtp_batch() does not return. */
1761 if (sender_address == NULL)
1762 moan_smtp_batch(smtp_cmd_buffer,
1763 "503 MAIL FROM:<sender> command must precede DATA");
1764 else
1765 moan_smtp_batch(smtp_cmd_buffer,
1766 "503 RCPT TO:<recipient> must precede DATA");
1767 }
1768 else
1769 {
1770 done = 3; /* DATA successfully achieved */
1771 message_ended = END_NOTENDED; /* Indicate in middle of message */
1772 }
1773 break;
1774
1775
1776 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1777
1778 case VRFY_CMD:
1779 case EXPN_CMD:
1780 case HELP_CMD:
1781 case NOOP_CMD:
1782 case ETRN_CMD:
1783 bsmtp_transaction_linecount = receive_linecount;
1784 break;
1785
1786
1787 case EOF_CMD:
1788 case QUIT_CMD:
1789 done = 2;
1790 break;
1791
1792
1793 case BADARG_CMD:
1794 /* The function moan_smtp_batch() does not return. */
1795 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1796 break;
1797
1798
1799 case BADCHAR_CMD:
1800 /* The function moan_smtp_batch() does not return. */
1801 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1802 break;
1803
1804
1805 default:
1806 /* The function moan_smtp_batch() does not return. */
1807 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1808 break;
1809 }
1810 }
1811
1812 return done - 2; /* Convert yield values */
1813 }
1814
1815
1816
1817
1818 /*************************************************
1819 * Start an SMTP session *
1820 *************************************************/
1821
1822 /* This function is called at the start of an SMTP session. Thereafter,
1823 smtp_setup_msg() is called to initiate each separate message. This
1824 function does host-specific testing, and outputs the banner line.
1825
1826 Arguments: none
1827 Returns: FALSE if the session can not continue; something has
1828 gone wrong, or the connection to the host is blocked
1829 */
1830
1831 BOOL
1832 smtp_start_session(void)
1833 {
1834 int size = 256;
1835 int ptr, esclen;
1836 uschar *user_msg, *log_msg;
1837 uschar *code, *esc;
1838 uschar *p, *s, *ss;
1839
1840 smtp_connection_start = time(NULL);
1841 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1842 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1843 smtp_ch_index = 0;
1844
1845 /* Default values for certain variables */
1846
1847 helo_seen = esmtp = helo_accept_junk = FALSE;
1848 smtp_mailcmd_count = 0;
1849 count_nonmail = TRUE_UNSET;
1850 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1851 smtp_delay_mail = smtp_rlm_base;
1852 auth_advertised = FALSE;
1853 pipelining_advertised = FALSE;
1854 pipelining_enable = TRUE;
1855 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1856 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1857
1858 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1859
1860 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1861 authentication settings from -oMaa to remain in force. */
1862
1863 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1864 authenticated_by = NULL;
1865
1866 #ifdef SUPPORT_TLS
1867 tls_in.cipher = tls_in.peerdn = NULL;
1868 tls_in.ourcert = tls_in.peercert = NULL;
1869 tls_in.sni = NULL;
1870 tls_in.ocsp = OCSP_NOT_REQ;
1871 tls_advertised = FALSE;
1872 #endif
1873 dsn_advertised = FALSE;
1874 #ifdef EXPERIMENTAL_INTERNATIONAL
1875 smtputf8_advertised = FALSE;
1876 #endif
1877
1878 /* Reset ACL connection variables */
1879
1880 acl_var_c = NULL;
1881
1882 /* Allow for trailing 0 in the command and data buffers. */
1883
1884 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1885 if (smtp_cmd_buffer == NULL)
1886 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1887 "malloc() failed for SMTP command buffer");
1888 smtp_cmd_buffer[0] = 0;
1889 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1890
1891 /* For batched input, the protocol setting can be overridden from the
1892 command line by a trusted caller. */
1893
1894 if (smtp_batched_input)
1895 {
1896 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1897 }
1898
1899 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1900 reset later if any of EHLO/AUTH/STARTTLS are received. */
1901
1902 else
1903 received_protocol =
1904 (sender_host_address ? protocols : protocols_local) [pnormal];
1905
1906 /* Set up the buffer for inputting using direct read() calls, and arrange to
1907 call the local functions instead of the standard C ones. */
1908
1909 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1910 if (smtp_inbuffer == NULL)
1911 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1912 receive_getc = smtp_getc;
1913 receive_ungetc = smtp_ungetc;
1914 receive_feof = smtp_feof;
1915 receive_ferror = smtp_ferror;
1916 receive_smtp_buffered = smtp_buffered;
1917 smtp_inptr = smtp_inend = smtp_inbuffer;
1918 smtp_had_eof = smtp_had_error = 0;
1919
1920 /* Set up the message size limit; this may be host-specific */
1921
1922 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1923 if (expand_string_message != NULL)
1924 {
1925 if (thismessage_size_limit == -1)
1926 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1927 "%s", expand_string_message);
1928 else
1929 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1930 "%s", expand_string_message);
1931 smtp_closedown(US"Temporary local problem - please try later");
1932 return FALSE;
1933 }
1934
1935 /* When a message is input locally via the -bs or -bS options, sender_host_
1936 unknown is set unless -oMa was used to force an IP address, in which case it
1937 is checked like a real remote connection. When -bs is used from inetd, this
1938 flag is not set, causing the sending host to be checked. The code that deals
1939 with IP source routing (if configured) is never required for -bs or -bS and
1940 the flag sender_host_notsocket is used to suppress it.
1941
1942 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1943 reserve for certain hosts and/or networks. */
1944
1945 if (!sender_host_unknown)
1946 {
1947 int rc;
1948 BOOL reserved_host = FALSE;
1949
1950 /* Look up IP options (source routing info) on the socket if this is not an
1951 -oMa "host", and if any are found, log them and drop the connection.
1952
1953 Linux (and others now, see below) is different to everyone else, so there
1954 has to be some conditional compilation here. Versions of Linux before 2.1.15
1955 used a structure whose name was "options". Somebody finally realized that
1956 this name was silly, and it got changed to "ip_options". I use the
1957 newer name here, but there is a fudge in the script that sets up os.h
1958 to define a macro in older Linux systems.
1959
1960 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1961 glibc 2, which has chosen ip_opts for the structure name. This is now
1962 really a glibc thing rather than a Linux thing, so the condition name
1963 has been changed to reflect this. It is relevant also to GNU/Hurd.
1964
1965 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1966 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1967 a special macro defined in the os.h file.
1968
1969 Some DGUX versions on older hardware appear not to support IP options at
1970 all, so there is now a general macro which can be set to cut out this
1971 support altogether.
1972
1973 How to do this properly in IPv6 is not yet known. */
1974
1975 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1976
1977 #ifdef GLIBC_IP_OPTIONS
1978 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1979 #define OPTSTYLE 1
1980 #else
1981 #define OPTSTYLE 2
1982 #endif
1983 #elif defined DARWIN_IP_OPTIONS
1984 #define OPTSTYLE 2
1985 #else
1986 #define OPTSTYLE 3
1987 #endif
1988
1989 if (!host_checking && !sender_host_notsocket)
1990 {
1991 #if OPTSTYLE == 1
1992 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1993 struct ip_options *ipopt = store_get(optlen);
1994 #elif OPTSTYLE == 2
1995 struct ip_opts ipoptblock;
1996 struct ip_opts *ipopt = &ipoptblock;
1997 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1998 #else
1999 struct ipoption ipoptblock;
2000 struct ipoption *ipopt = &ipoptblock;
2001 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2002 #endif
2003
2004 /* Occasional genuine failures of getsockopt() have been seen - for
2005 example, "reset by peer". Therefore, just log and give up on this
2006 call, unless the error is ENOPROTOOPT. This error is given by systems
2007 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2008 of writing. So for that error, carry on - we just can't do an IP options
2009 check. */
2010
2011 DEBUG(D_receive) debug_printf("checking for IP options\n");
2012
2013 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2014 &optlen) < 0)
2015 {
2016 if (errno != ENOPROTOOPT)
2017 {
2018 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2019 host_and_ident(FALSE), strerror(errno));
2020 smtp_printf("451 SMTP service not available\r\n");
2021 return FALSE;
2022 }
2023 }
2024
2025 /* Deal with any IP options that are set. On the systems I have looked at,
2026 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2027 more logging data than will fit in big_buffer. Nevertheless, after somebody
2028 questioned this code, I've added in some paranoid checking. */
2029
2030 else if (optlen > 0)
2031 {
2032 uschar *p = big_buffer;
2033 uschar *pend = big_buffer + big_buffer_size;
2034 uschar *opt, *adptr;
2035 int optcount;
2036 struct in_addr addr;
2037
2038 #if OPTSTYLE == 1
2039 uschar *optstart = (uschar *)(ipopt->__data);
2040 #elif OPTSTYLE == 2
2041 uschar *optstart = (uschar *)(ipopt->ip_opts);
2042 #else
2043 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2044 #endif
2045
2046 DEBUG(D_receive) debug_printf("IP options exist\n");
2047
2048 Ustrcpy(p, "IP options on incoming call:");
2049 p += Ustrlen(p);
2050
2051 for (opt = optstart; opt != NULL &&
2052 opt < (uschar *)(ipopt) + optlen;)
2053 {
2054 switch (*opt)
2055 {
2056 case IPOPT_EOL:
2057 opt = NULL;
2058 break;
2059
2060 case IPOPT_NOP:
2061 opt++;
2062 break;
2063
2064 case IPOPT_SSRR:
2065 case IPOPT_LSRR:
2066 if (!string_format(p, pend-p, " %s [@%s",
2067 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2068 #if OPTSTYLE == 1
2069 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2070 #elif OPTSTYLE == 2
2071 inet_ntoa(ipopt->ip_dst)))
2072 #else
2073 inet_ntoa(ipopt->ipopt_dst)))
2074 #endif
2075 {
2076 opt = NULL;
2077 break;
2078 }
2079
2080 p += Ustrlen(p);
2081 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2082 adptr = opt + 3;
2083 while (optcount-- > 0)
2084 {
2085 memcpy(&addr, adptr, sizeof(addr));
2086 if (!string_format(p, pend - p - 1, "%s%s",
2087 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2088 {
2089 opt = NULL;
2090 break;
2091 }
2092 p += Ustrlen(p);
2093 adptr += sizeof(struct in_addr);
2094 }
2095 *p++ = ']';
2096 opt += opt[1];
2097 break;
2098
2099 default:
2100 {
2101 int i;
2102 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2103 Ustrcat(p, "[ ");
2104 p += 2;
2105 for (i = 0; i < opt[1]; i++)
2106 {
2107 sprintf(CS p, "%2.2x ", opt[i]);
2108 p += 3;
2109 }
2110 *p++ = ']';
2111 }
2112 opt += opt[1];
2113 break;
2114 }
2115 }
2116
2117 *p = 0;
2118 log_write(0, LOG_MAIN, "%s", big_buffer);
2119
2120 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2121
2122 log_write(0, LOG_MAIN|LOG_REJECT,
2123 "connection from %s refused (IP options)", host_and_ident(FALSE));
2124
2125 smtp_printf("554 SMTP service not available\r\n");
2126 return FALSE;
2127 }
2128
2129 /* Length of options = 0 => there are no options */
2130
2131 else DEBUG(D_receive) debug_printf("no IP options found\n");
2132 }
2133 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2134
2135 /* Set keep-alive in socket options. The option is on by default. This
2136 setting is an attempt to get rid of some hanging connections that stick in
2137 read() when the remote end (usually a dialup) goes away. */
2138
2139 if (smtp_accept_keepalive && !sender_host_notsocket)
2140 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2141
2142 /* If the current host matches host_lookup, set the name by doing a
2143 reverse lookup. On failure, sender_host_name will be NULL and
2144 host_lookup_failed will be TRUE. This may or may not be serious - optional
2145 checks later. */
2146
2147 if (verify_check_host(&host_lookup) == OK)
2148 {
2149 (void)host_name_lookup();
2150 host_build_sender_fullhost();
2151 }
2152
2153 /* Delay this until we have the full name, if it is looked up. */
2154
2155 set_process_info("handling incoming connection from %s",
2156 host_and_ident(FALSE));
2157
2158 /* Expand smtp_receive_timeout, if needed */
2159
2160 if (smtp_receive_timeout_s)
2161 {
2162 uschar * exp;
2163 if ( !(exp = expand_string(smtp_receive_timeout_s))
2164 || !(*exp)
2165 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2166 )
2167 log_write(0, LOG_MAIN|LOG_PANIC,
2168 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2169 }
2170
2171 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2172 smtps port for use with older style SSL MTAs. */
2173
2174 #ifdef SUPPORT_TLS
2175 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2176 return FALSE;
2177 #endif
2178
2179 /* Test for explicit connection rejection */
2180
2181 if (verify_check_host(&host_reject_connection) == OK)
2182 {
2183 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2184 "from %s (host_reject_connection)", host_and_ident(FALSE));
2185 smtp_printf("554 SMTP service not available\r\n");
2186 return FALSE;
2187 }
2188
2189 /* Test with TCP Wrappers if so configured. There is a problem in that
2190 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2191 such as disks dying. In these cases, it is desirable to reject with a 4xx
2192 error instead of a 5xx error. There isn't a "right" way to detect such
2193 problems. The following kludge is used: errno is zeroed before calling
2194 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2195 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2196 not exist). */
2197
2198 #ifdef USE_TCP_WRAPPERS
2199 errno = 0;
2200 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2201 if (tcp_wrappers_name == NULL)
2202 {
2203 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2204 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2205 expand_string_message);
2206 }
2207 if (!hosts_ctl(tcp_wrappers_name,
2208 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2209 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2210 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2211 {
2212 if (errno == 0 || errno == ENOENT)
2213 {
2214 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2215 log_write(L_connection_reject,
2216 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2217 "(tcp wrappers)", host_and_ident(FALSE));
2218 smtp_printf("554 SMTP service not available\r\n");
2219 }
2220 else
2221 {
2222 int save_errno = errno;
2223 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2224 "errno value %d\n", save_errno);
2225 log_write(L_connection_reject,
2226 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2227 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2228 smtp_printf("451 Temporary local problem - please try later\r\n");
2229 }
2230 return FALSE;
2231 }
2232 #endif
2233
2234 /* Check for reserved slots. The value of smtp_accept_count has already been
2235 incremented to include this process. */
2236
2237 if (smtp_accept_max > 0 &&
2238 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2239 {
2240 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2241 {
2242 log_write(L_connection_reject,
2243 LOG_MAIN, "temporarily refused connection from %s: not in "
2244 "reserve list: connected=%d max=%d reserve=%d%s",
2245 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2246 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2247 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2248 "please try again later\r\n", smtp_active_hostname);
2249 return FALSE;
2250 }
2251 reserved_host = TRUE;
2252 }
2253
2254 /* If a load level above which only messages from reserved hosts are
2255 accepted is set, check the load. For incoming calls via the daemon, the
2256 check is done in the superior process if there are no reserved hosts, to
2257 save a fork. In all cases, the load average will already be available
2258 in a global variable at this point. */
2259
2260 if (smtp_load_reserve >= 0 &&
2261 load_average > smtp_load_reserve &&
2262 !reserved_host &&
2263 verify_check_host(&smtp_reserve_hosts) != OK)
2264 {
2265 log_write(L_connection_reject,
2266 LOG_MAIN, "temporarily refused connection from %s: not in "
2267 "reserve list and load average = %.2f", host_and_ident(FALSE),
2268 (double)load_average/1000.0);
2269 smtp_printf("421 %s: Too much load; please try again later\r\n",
2270 smtp_active_hostname);
2271 return FALSE;
2272 }
2273
2274 /* Determine whether unqualified senders or recipients are permitted
2275 for this host. Unfortunately, we have to do this every time, in order to
2276 set the flags so that they can be inspected when considering qualifying
2277 addresses in the headers. For a site that permits no qualification, this
2278 won't take long, however. */
2279
2280 allow_unqualified_sender =
2281 verify_check_host(&sender_unqualified_hosts) == OK;
2282
2283 allow_unqualified_recipient =
2284 verify_check_host(&recipient_unqualified_hosts) == OK;
2285
2286 /* Determine whether HELO/EHLO is required for this host. The requirement
2287 can be hard or soft. */
2288
2289 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2290 if (!helo_required)
2291 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2292
2293 /* Determine whether this hosts is permitted to send syntactic junk
2294 after a HELO or EHLO command. */
2295
2296 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2297 }
2298
2299 /* For batch SMTP input we are now done. */
2300
2301 if (smtp_batched_input) return TRUE;
2302
2303 #ifdef EXPERIMENTAL_PROXY
2304 /* If valid Proxy Protocol source is connecting, set up session.
2305 * Failure will not allow any SMTP function other than QUIT. */
2306 proxy_session = FALSE;
2307 proxy_session_failed = FALSE;
2308 if (check_proxy_protocol_host())
2309 {
2310 if (setup_proxy_protocol_host() == FALSE)
2311 {
2312 proxy_session_failed = TRUE;
2313 DEBUG(D_receive)
2314 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2315 }
2316 else
2317 {
2318 sender_host_name = NULL;
2319 (void)host_name_lookup();
2320 host_build_sender_fullhost();
2321 }
2322 }
2323 #endif
2324
2325 /* Run the ACL if it exists */
2326
2327 user_msg = NULL;
2328 if (acl_smtp_connect != NULL)
2329 {
2330 int rc;
2331 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2332 &log_msg);
2333 if (rc != OK)
2334 {
2335 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2336 return FALSE;
2337 }
2338 }
2339
2340 /* Output the initial message for a two-way SMTP connection. It may contain
2341 newlines, which then cause a multi-line response to be given. */
2342
2343 code = US"220"; /* Default status code */
2344 esc = US""; /* Default extended status code */
2345 esclen = 0; /* Length of esc */
2346
2347 if (user_msg == NULL)
2348 {
2349 s = expand_string(smtp_banner);
2350 if (s == NULL)
2351 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2352 "failed: %s", smtp_banner, expand_string_message);
2353 }
2354 else
2355 {
2356 int codelen = 3;
2357 s = user_msg;
2358 smtp_message_code(&code, &codelen, &s, NULL);
2359 if (codelen > 4)
2360 {
2361 esc = code + 4;
2362 esclen = codelen - 4;
2363 }
2364 }
2365
2366 /* Remove any terminating newlines; might as well remove trailing space too */
2367
2368 p = s + Ustrlen(s);
2369 while (p > s && isspace(p[-1])) p--;
2370 *p = 0;
2371
2372 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2373 is all contained in a single IP packet. The original code wrote out the
2374 greeting using several calls to fprint/fputc, and on busy servers this could
2375 cause it to be split over more than one packet - which caused CC:Mail to fall
2376 over when it got the second part of the greeting after sending its first
2377 command. Sigh. To try to avoid this, build the complete greeting message
2378 first, and output it in one fell swoop. This gives a better chance of it
2379 ending up as a single packet. */
2380
2381 ss = store_get(size);
2382 ptr = 0;
2383
2384 p = s;
2385 do /* At least once, in case we have an empty string */
2386 {
2387 int len;
2388 uschar *linebreak = Ustrchr(p, '\n');
2389 ss = string_cat(ss, &size, &ptr, code, 3);
2390 if (linebreak == NULL)
2391 {
2392 len = Ustrlen(p);
2393 ss = string_cat(ss, &size, &ptr, US" ", 1);
2394 }
2395 else
2396 {
2397 len = linebreak - p;
2398 ss = string_cat(ss, &size, &ptr, US"-", 1);
2399 }
2400 ss = string_cat(ss, &size, &ptr, esc, esclen);
2401 ss = string_cat(ss, &size, &ptr, p, len);
2402 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
2403 p += len;
2404 if (linebreak != NULL) p++;
2405 }
2406 while (*p != 0);
2407
2408 ss[ptr] = 0; /* string_cat leaves room for this */
2409
2410 /* Before we write the banner, check that there is no input pending, unless
2411 this synchronisation check is disabled. */
2412
2413 if (!check_sync())
2414 {
2415 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2416 "synchronization error (input sent without waiting for greeting): "
2417 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2418 string_printing(smtp_inptr));
2419 smtp_printf("554 SMTP synchronization error\r\n");
2420 return FALSE;
2421 }
2422
2423 /* Now output the banner */
2424
2425 smtp_printf("%s", ss);
2426 return TRUE;
2427 }
2428
2429
2430
2431
2432
2433 /*************************************************
2434 * Handle SMTP syntax and protocol errors *
2435 *************************************************/
2436
2437 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2438 to do so. Then transmit the error response. The return value depends on the
2439 number of syntax and protocol errors in this SMTP session.
2440
2441 Arguments:
2442 type error type, given as a log flag bit
2443 code response code; <= 0 means don't send a response
2444 data data to reflect in the response (can be NULL)
2445 errmess the error message
2446
2447 Returns: -1 limit of syntax/protocol errors NOT exceeded
2448 +1 limit of syntax/protocol errors IS exceeded
2449
2450 These values fit in with the values of the "done" variable in the main
2451 processing loop in smtp_setup_msg(). */
2452
2453 static int
2454 synprot_error(int type, int code, uschar *data, uschar *errmess)
2455 {
2456 int yield = -1;
2457
2458 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2459 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2460 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2461
2462 if (++synprot_error_count > smtp_max_synprot_errors)
2463 {
2464 yield = 1;
2465 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2466 "syntax or protocol errors (last command was \"%s\")",
2467 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2468 }
2469
2470 if (code > 0)
2471 {
2472 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2473 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2474 if (yield == 1)
2475 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2476 }
2477
2478 return yield;
2479 }
2480
2481
2482
2483
2484 /*************************************************
2485 * Log incomplete transactions *
2486 *************************************************/
2487
2488 /* This function is called after a transaction has been aborted by RSET, QUIT,
2489 connection drops or other errors. It logs the envelope information received
2490 so far in order to preserve address verification attempts.
2491
2492 Argument: string to indicate what aborted the transaction
2493 Returns: nothing
2494 */
2495
2496 static void
2497 incomplete_transaction_log(uschar *what)
2498 {
2499 if (sender_address == NULL || /* No transaction in progress */
2500 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
2501 ) return;
2502
2503 /* Build list of recipients for logging */
2504
2505 if (recipients_count > 0)
2506 {
2507 int i;
2508 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2509 for (i = 0; i < recipients_count; i++)
2510 raw_recipients[i] = recipients_list[i].address;
2511 raw_recipients_count = recipients_count;
2512 }
2513
2514 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2515 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2516 }
2517
2518
2519
2520
2521 /*************************************************
2522 * Send SMTP response, possibly multiline *
2523 *************************************************/
2524
2525 /* There are, it seems, broken clients out there that cannot handle multiline
2526 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2527 output nothing for non-final calls, and only the first line for anything else.
2528
2529 Arguments:
2530 code SMTP code, may involve extended status codes
2531 codelen length of smtp code; if > 4 there's an ESC
2532 final FALSE if the last line isn't the final line
2533 msg message text, possibly containing newlines
2534
2535 Returns: nothing
2536 */
2537
2538 void
2539 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2540 {
2541 int esclen = 0;
2542 uschar *esc = US"";
2543
2544 if (!final && no_multiline_responses) return;
2545
2546 if (codelen > 4)
2547 {
2548 esc = code + 4;
2549 esclen = codelen - 4;
2550 }
2551
2552 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2553 have had the same. Note: this code is also present in smtp_printf(). It would
2554 be tidier to have it only in one place, but when it was added, it was easier to
2555 do it that way, so as not to have to mess with the code for the RCPT command,
2556 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2557
2558 if (rcpt_in_progress)
2559 {
2560 if (rcpt_smtp_response == NULL)
2561 rcpt_smtp_response = string_copy(msg);
2562 else if (rcpt_smtp_response_same &&
2563 Ustrcmp(rcpt_smtp_response, msg) != 0)
2564 rcpt_smtp_response_same = FALSE;
2565 rcpt_in_progress = FALSE;
2566 }
2567
2568 /* Not output the message, splitting it up into multiple lines if necessary. */
2569
2570 for (;;)
2571 {
2572 uschar *nl = Ustrchr(msg, '\n');
2573 if (nl == NULL)
2574 {
2575 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2576 return;
2577 }
2578 else if (nl[1] == 0 || no_multiline_responses)
2579 {
2580 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2581 (int)(nl - msg), msg);
2582 return;
2583 }
2584 else
2585 {
2586 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2587 msg = nl + 1;
2588 while (isspace(*msg)) msg++;
2589 }
2590 }
2591 }
2592
2593
2594
2595
2596 /*************************************************
2597 * Parse user SMTP message *
2598 *************************************************/
2599
2600 /* This function allows for user messages overriding the response code details
2601 by providing a suitable response code string at the start of the message
2602 user_msg. Check the message for starting with a response code and optionally an
2603 extended status code. If found, check that the first digit is valid, and if so,
2604 change the code pointer and length to use the replacement. An invalid code
2605 causes a panic log; in this case, if the log messages is the same as the user
2606 message, we must also adjust the value of the log message to show the code that
2607 is actually going to be used (the original one).
2608
2609 This function is global because it is called from receive.c as well as within
2610 this module.
2611
2612 Note that the code length returned includes the terminating whitespace
2613 character, which is always included in the regex match.
2614
2615 Arguments:
2616 code SMTP code, may involve extended status codes
2617 codelen length of smtp code; if > 4 there's an ESC
2618 msg message text
2619 log_msg optional log message, to be adjusted with the new SMTP code
2620
2621 Returns: nothing
2622 */
2623
2624 void
2625 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2626 {
2627 int n;
2628 int ovector[3];
2629
2630 if (msg == NULL || *msg == NULL) return;
2631
2632 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2633 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2634 if (n < 0) return;
2635
2636 if ((*msg)[0] != (*code)[0])
2637 {
2638 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2639 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2640 if (log_msg != NULL && *log_msg == *msg)
2641 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2642 }
2643 else
2644 {
2645 *code = *msg;
2646 *codelen = ovector[1]; /* Includes final space */
2647 }
2648 *msg += ovector[1]; /* Chop the code off the message */
2649 return;
2650 }
2651
2652
2653
2654
2655 /*************************************************
2656 * Handle an ACL failure *
2657 *************************************************/
2658
2659 /* This function is called when acl_check() fails. As well as calls from within
2660 this module, it is called from receive.c for an ACL after DATA. It sorts out
2661 logging the incident, and sets up the error response. A message containing
2662 newlines is turned into a multiline SMTP response, but for logging, only the
2663 first line is used.
2664
2665 There's a table of default permanent failure response codes to use in
2666 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2667 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2668 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2669 state, because there are broken clients that try VRFY before RCPT. A 5xx
2670 response should be given only when the address is positively known to be
2671 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2672 503.
2673
2674 From Exim 4.63, it is possible to override the response code details by
2675 providing a suitable response code string at the start of the message provided
2676 in user_msg. The code's first digit is checked for validity.
2677
2678 Arguments:
2679 where where the ACL was called from
2680 rc the failure code
2681 user_msg a message that can be included in an SMTP response
2682 log_msg a message for logging
2683
2684 Returns: 0 in most cases
2685 2 if the failure code was FAIL_DROP, in which case the
2686 SMTP connection should be dropped (this value fits with the
2687 "done" variable in smtp_setup_msg() below)
2688 */
2689
2690 int
2691 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2692 {
2693 BOOL drop = rc == FAIL_DROP;
2694 int codelen = 3;
2695 uschar *smtp_code;
2696 uschar *lognl;
2697 uschar *sender_info = US"";
2698 uschar *what =
2699 #ifdef WITH_CONTENT_SCAN
2700 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2701 #endif
2702 (where == ACL_WHERE_PREDATA)? US"DATA" :
2703 (where == ACL_WHERE_DATA)? US"after DATA" :
2704 #ifndef DISABLE_PRDR
2705 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2706 #endif
2707 (smtp_cmd_data == NULL)?
2708 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2709 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2710
2711 if (drop) rc = FAIL;
2712
2713 /* Set the default SMTP code, and allow a user message to change it. */
2714
2715 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2716 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2717
2718 /* We used to have sender_address here; however, there was a bug that was not
2719 updating sender_address after a rewrite during a verify. When this bug was
2720 fixed, sender_address at this point became the rewritten address. I'm not sure
2721 this is what should be logged, so I've changed to logging the unrewritten
2722 address to retain backward compatibility. */
2723
2724 #ifndef WITH_CONTENT_SCAN
2725 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2726 #else
2727 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2728 #endif
2729 {
2730 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2731 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2732 sender_host_authenticated ? US" A=" : US"",
2733 sender_host_authenticated ? sender_host_authenticated : US"",
2734 sender_host_authenticated && authenticated_id ? US":" : US"",
2735 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2736 );
2737 }
2738
2739 /* If there's been a sender verification failure with a specific message, and
2740 we have not sent a response about it yet, do so now, as a preliminary line for
2741 failures, but not defers. However, always log it for defer, and log it for fail
2742 unless the sender_verify_fail log selector has been turned off. */
2743
2744 if (sender_verified_failed != NULL &&
2745 !testflag(sender_verified_failed, af_sverify_told))
2746 {
2747 BOOL save_rcpt_in_progress = rcpt_in_progress;
2748 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2749
2750 setflag(sender_verified_failed, af_sverify_told);
2751
2752 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2753 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2754 host_and_ident(TRUE),
2755 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2756 sender_verified_failed->address,
2757 (sender_verified_failed->message == NULL)? US"" :
2758 string_sprintf(": %s", sender_verified_failed->message));
2759
2760 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2761 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2762 testflag(sender_verified_failed, af_verify_pmfail)?
2763 "Postmaster verification failed while checking <%s>\n%s\n"
2764 "Several RFCs state that you are required to have a postmaster\n"
2765 "mailbox for each mail domain. This host does not accept mail\n"
2766 "from domains whose servers reject the postmaster address."
2767 :
2768 testflag(sender_verified_failed, af_verify_nsfail)?
2769 "Callback setup failed while verifying <%s>\n%s\n"
2770 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2771 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2772 "RFC requirements, and stops you from receiving standard bounce\n"
2773 "messages. This host does not accept mail from domains whose servers\n"
2774 "refuse bounces."
2775 :
2776 "Verification failed for <%s>\n%s",
2777 sender_verified_failed->address,
2778 sender_verified_failed->user_message));
2779
2780 rcpt_in_progress = save_rcpt_in_progress;
2781 }
2782
2783 /* Sort out text for logging */
2784
2785 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2786 lognl = Ustrchr(log_msg, '\n');
2787 if (lognl != NULL) *lognl = 0;
2788
2789 /* Send permanent failure response to the command, but the code used isn't
2790 always a 5xx one - see comments at the start of this function. If the original
2791 rc was FAIL_DROP we drop the connection and yield 2. */
2792
2793 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2794 US"Administrative prohibition" : user_msg);
2795
2796 /* Send temporary failure response to the command. Don't give any details,
2797 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2798 verb, and for a header verify when smtp_return_error_details is set.
2799
2800 This conditional logic is all somewhat of a mess because of the odd
2801 interactions between temp_details and return_error_details. One day it should
2802 be re-implemented in a tidier fashion. */
2803
2804 else
2805 {
2806 if (acl_temp_details && user_msg != NULL)
2807 {
2808 if (smtp_return_error_details &&
2809 sender_verified_failed != NULL &&
2810 sender_verified_failed->message != NULL)
2811 {
2812 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2813 }
2814 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2815 }
2816 else
2817 smtp_respond(smtp_code, codelen, TRUE,
2818 US"Temporary local problem - please try later");
2819 }
2820
2821 /* Log the incident to the logs that are specified by log_reject_target
2822 (default main, reject). This can be empty to suppress logging of rejections. If
2823 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2824 is closing if required and return 2. */
2825
2826 if (log_reject_target != 0)
2827 {
2828 #ifdef SUPPORT_TLS
2829 uschar * s = s_tlslog(NULL, NULL, NULL);
2830 if (!s) s = US"";
2831 #else
2832 uschar * s = US"";
2833 #endif
2834 log_write(0, log_reject_target, "%s%s %s%srejected %s%s",
2835 host_and_ident(TRUE), s,
2836 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2837 }
2838
2839 if (!drop) return 0;
2840
2841 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2842 smtp_get_connection_info());
2843
2844 /* Run the not-quit ACL, but without any custom messages. This should not be a
2845 problem, because we get here only if some other ACL has issued "drop", and
2846 in that case, *its* custom messages will have been used above. */
2847
2848 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2849 return 2;
2850 }
2851
2852
2853
2854
2855 /*************************************************
2856 * Handle SMTP exit when QUIT is not given *
2857 *************************************************/
2858
2859 /* This function provides a logging/statistics hook for when an SMTP connection
2860 is dropped on the floor or the other end goes away. It's a global function
2861 because it's called from receive.c as well as this module. As well as running
2862 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2863 response, either with a custom message from the ACL, or using a default. There
2864 is one case, however, when no message is output - after "drop". In that case,
2865 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2866 passed to this function.
2867
2868 In case things go wrong while processing this function, causing an error that
2869 may re-enter this funtion, there is a recursion check.
2870
2871 Arguments:
2872 reason What $smtp_notquit_reason will be set to in the ACL;
2873 if NULL, the ACL is not run
2874 code The error code to return as part of the response
2875 defaultrespond The default message if there's no user_msg
2876
2877 Returns: Nothing
2878 */
2879
2880 void
2881 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2882 {
2883 int rc;
2884 uschar *user_msg = NULL;
2885 uschar *log_msg = NULL;
2886
2887 /* Check for recursive acll */
2888
2889 if (smtp_exit_function_called)
2890 {
2891 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2892 reason);
2893 return;
2894 }
2895 smtp_exit_function_called = TRUE;
2896
2897 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2898
2899 if (acl_smtp_notquit != NULL && reason != NULL)
2900 {
2901 smtp_notquit_reason = reason;
2902 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2903 &log_msg);
2904 if (rc == ERROR)
2905 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2906 log_msg);
2907 }
2908
2909 /* Write an SMTP response if we are expected to give one. As the default
2910 responses are all internal, they should always fit in the buffer, but code a
2911 warning, just in case. Note that string_vformat() still leaves a complete
2912 string, even if it is incomplete. */
2913
2914 if (code != NULL && defaultrespond != NULL)
2915 {
2916 if (user_msg == NULL)
2917 {
2918 uschar buffer[128];
2919 va_list ap;
2920 va_start(ap, defaultrespond);
2921 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2922 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2923 smtp_printf("%s %s\r\n", code, buffer);
2924 va_end(ap);
2925 }
2926 else
2927 smtp_respond(code, 3, TRUE, user_msg);
2928 mac_smtp_fflush();
2929 }
2930 }
2931
2932
2933
2934
2935 /*************************************************
2936 * Verify HELO argument *
2937 *************************************************/
2938
2939 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2940 matched. It is also called from ACL processing if verify = helo is used and
2941 verification was not previously tried (i.e. helo_try_verify_hosts was not
2942 matched). The result of its processing is to set helo_verified and
2943 helo_verify_failed. These variables should both be FALSE for this function to
2944 be called.
2945
2946 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2947 for IPv6 ::ffff: literals.
2948
2949 Argument: none
2950 Returns: TRUE if testing was completed;
2951 FALSE on a temporary failure
2952 */
2953
2954 BOOL
2955 smtp_verify_helo(void)
2956 {
2957 BOOL yield = TRUE;
2958
2959 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2960 sender_helo_name);
2961
2962 if (sender_helo_name == NULL)
2963 {
2964 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2965 }
2966
2967 /* Deal with the case of -bs without an IP address */
2968
2969 else if (sender_host_address == NULL)
2970 {
2971 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2972 helo_verified = TRUE;
2973 }
2974
2975 /* Deal with the more common case when there is a sending IP address */
2976
2977 else if (sender_helo_name[0] == '[')
2978 {
2979 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2980 Ustrlen(sender_host_address)) == 0;
2981
2982 #if HAVE_IPV6
2983 if (!helo_verified)
2984 {
2985 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2986 helo_verified = Ustrncmp(sender_helo_name + 1,
2987 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2988 }
2989 #endif
2990
2991 HDEBUG(D_receive)
2992 { if (helo_verified) debug_printf("matched host address\n"); }
2993 }
2994
2995 /* Do a reverse lookup if one hasn't already given a positive or negative
2996 response. If that fails, or the name doesn't match, try checking with a forward
2997 lookup. */
2998
2999 else
3000 {
3001 if (sender_host_name == NULL && !host_lookup_failed)
3002 yield = host_name_lookup() != DEFER;
3003
3004 /* If a host name is known, check it and all its aliases. */
3005
3006 if (sender_host_name != NULL)
3007 {
3008 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
3009
3010 if (helo_verified)
3011 {
3012 HDEBUG(D_receive) debug_printf("matched host name\n");
3013 }
3014 else
3015 {
3016 uschar **aliases = sender_host_aliases;
3017 while (*aliases != NULL)
3018 {
3019 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
3020 if (helo_verified) break;
3021 }
3022 HDEBUG(D_receive)
3023 {
3024 if (helo_verified)
3025 debug_printf("matched alias %s\n", *(--aliases));
3026 }
3027 }
3028 }
3029
3030 /* Final attempt: try a forward lookup of the helo name */
3031
3032 if (!helo_verified)
3033 {
3034 int rc;
3035 host_item h;
3036 h.name = sender_helo_name;
3037 h.address = NULL;
3038 h.mx = MX_NONE;
3039 h.next = NULL;
3040 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3041 sender_helo_name);
3042 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
3043 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3044 {
3045 host_item *hh = &h;
3046 while (hh != NULL)
3047 {
3048 if (Ustrcmp(hh->address, sender_host_address) == 0)
3049 {
3050 helo_verified = TRUE;
3051 HDEBUG(D_receive)
3052 debug_printf("IP address for %s matches calling address\n",
3053 sender_helo_name);
3054 break;
3055 }
3056 hh = hh->next;
3057 }
3058 }
3059 }
3060 }
3061
3062 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3063 return yield;
3064 }
3065
3066
3067
3068
3069 /*************************************************
3070 * Send user response message *
3071 *************************************************/
3072
3073 /* This function is passed a default response code and a user message. It calls
3074 smtp_message_code() to check and possibly modify the response code, and then
3075 calls smtp_respond() to transmit the response. I put this into a function
3076 just to avoid a lot of repetition.
3077
3078 Arguments:
3079 code the response code
3080 user_msg the user message
3081
3082 Returns: nothing
3083 */
3084
3085 static void
3086 smtp_user_msg(uschar *code, uschar *user_msg)
3087 {
3088 int len = 3;
3089 smtp_message_code(&code, &len, &user_msg, NULL);
3090 smtp_respond(code, len, TRUE, user_msg);
3091 }
3092
3093
3094
3095 /*************************************************
3096 * Initialize for SMTP incoming message *
3097 *************************************************/
3098
3099 /* This function conducts the initial dialogue at the start of an incoming SMTP
3100 message, and builds a list of recipients. However, if the incoming message
3101 is part of a batch (-bS option) a separate function is called since it would
3102 be messy having tests splattered about all over this function. This function
3103 therefore handles the case where interaction is occurring. The input and output
3104 files are set up in smtp_in and smtp_out.
3105
3106 The global recipients_list is set to point to a vector of recipient_item
3107 blocks, whose number is given by recipients_count. This is extended by the
3108 receive_add_recipient() function. The global variable sender_address is set to
3109 the sender's address. The yield is +1 if a message has been successfully
3110 started, 0 if a QUIT command was encountered or the connection was refused from
3111 the particular host, or -1 if the connection was lost.
3112
3113 Argument: none
3114
3115 Returns: > 0 message successfully started (reached DATA)
3116 = 0 QUIT read or end of file reached or call refused
3117 < 0 lost connection
3118 */
3119
3120 int
3121 smtp_setup_msg(void)
3122 {
3123 int done = 0;
3124 BOOL toomany = FALSE;
3125 BOOL discarded = FALSE;
3126 BOOL last_was_rej_mail = FALSE;
3127 BOOL last_was_rcpt = FALSE;
3128 void *reset_point = store_get(0);
3129
3130 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3131
3132 /* Reset for start of new message. We allow one RSET not to be counted as a
3133 nonmail command, for those MTAs that insist on sending it between every
3134 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3135 TLS between messages (an Exim client may do this if it has messages queued up
3136 for the host). Note: we do NOT reset AUTH at this point. */
3137
3138 smtp_reset(reset_point);
3139 message_ended = END_NOTSTARTED;
3140
3141 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3142 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3143 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3144 #ifdef SUPPORT_TLS
3145 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3146 #endif
3147
3148 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3149
3150 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3151
3152 /* Batched SMTP is handled in a different function. */
3153
3154 if (smtp_batched_input) return smtp_setup_batch_msg();
3155
3156 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3157 value. The values are 2 larger than the required yield of the function. */
3158
3159 while (done <= 0)
3160 {
3161 const uschar **argv;
3162 uschar *etrn_command;
3163 uschar *etrn_serialize_key;
3164 uschar *errmess;
3165 uschar *log_msg, *smtp_code;
3166 uschar *user_msg = NULL;
3167 uschar *recipient = NULL;
3168 uschar *hello = NULL;
3169 const uschar *set_id = NULL;
3170 uschar *s, *ss;
3171 BOOL was_rej_mail = FALSE;
3172 BOOL was_rcpt = FALSE;
3173 void (*oldsignal)(int);
3174 pid_t pid;
3175 int start, end, sender_domain, recipient_domain;
3176 int ptr, size, rc;
3177 int c, i;
3178 auth_instance *au;
3179 uschar *orcpt = NULL;
3180 int flags;
3181
3182 switch(smtp_read_command(TRUE))
3183 {
3184 /* The AUTH command is not permitted to occur inside a transaction, and may
3185 occur successfully only once per connection. Actually, that isn't quite
3186 true. When TLS is started, all previous information about a connection must
3187 be discarded, so a new AUTH is permitted at that time.
3188
3189 AUTH may only be used when it has been advertised. However, it seems that
3190 there are clients that send AUTH when it hasn't been advertised, some of
3191 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3192 So there's a get-out that allows this to happen.
3193
3194 AUTH is initially labelled as a "nonmail command" so that one occurrence
3195 doesn't get counted. We change the label here so that multiple failing
3196 AUTHS will eventually hit the nonmail threshold. */
3197
3198 case AUTH_CMD:
3199 HAD(SCH_AUTH);
3200 authentication_failed = TRUE;
3201 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3202
3203 if (!auth_advertised && !allow_auth_unadvertised)
3204 {
3205 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3206 US"AUTH command used when not advertised");
3207 break;
3208 }
3209 if (sender_host_authenticated != NULL)
3210 {
3211 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3212 US"already authenticated");
3213 break;
3214 }
3215 if (sender_address != NULL)
3216 {
3217 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3218 US"not permitted in mail transaction");
3219 break;
3220 }
3221
3222 /* Check the ACL */
3223
3224 if (acl_smtp_auth != NULL)
3225 {
3226 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
3227 if (rc != OK)
3228 {
3229 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3230 break;
3231 }
3232 }
3233
3234 /* Find the name of the requested authentication mechanism. */
3235
3236 s = smtp_cmd_data;
3237 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3238 {
3239 if (!isalnum(c) && c != '-' && c != '_')
3240 {
3241 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3242 US"invalid character in authentication mechanism name");
3243 goto COMMAND_LOOP;
3244 }
3245 smtp_cmd_data++;
3246 }
3247
3248 /* If not at the end of the line, we must be at white space. Terminate the
3249 name and move the pointer on to any data that may be present. */
3250
3251 if (*smtp_cmd_data != 0)
3252 {
3253 *smtp_cmd_data++ = 0;
3254 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3255 }
3256
3257 /* Search for an authentication mechanism which is configured for use
3258 as a server and which has been advertised (unless, sigh, allow_auth_
3259 unadvertised is set). */
3260
3261 for (au = auths; au != NULL; au = au->next)
3262 {
3263 if (strcmpic(s, au->public_name) == 0 && au->server &&
3264 (au->advertised || allow_auth_unadvertised)) break;
3265 }
3266
3267 if (au == NULL)
3268 {
3269 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3270 string_sprintf("%s authentication mechanism not supported", s));
3271 break;
3272 }
3273
3274 /* Run the checking code, passing the remainder of the command line as
3275 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3276 it as the only set numerical variable. The authenticator may set $auth<n>
3277 and also set other numeric variables. The $auth<n> variables are preferred
3278 nowadays; the numerical variables remain for backwards compatibility.
3279
3280 Afterwards, have a go at expanding the set_id string, even if
3281 authentication failed - for bad passwords it can be useful to log the
3282 userid. On success, require set_id to expand and exist, and put it in
3283 authenticated_id. Save this in permanent store, as the working store gets
3284 reset at HELO, RSET, etc. */
3285
3286 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3287 expand_nmax = 0;
3288 expand_nlength[0] = 0; /* $0 contains nothing */
3289
3290 c = (au->info->servercode)(au, smtp_cmd_data);
3291 if (au->set_id != NULL) set_id = expand_string(au->set_id);
3292 expand_nmax = -1; /* Reset numeric variables */
3293 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3294
3295 /* The value of authenticated_id is stored in the spool file and printed in
3296 log lines. It must not contain binary zeros or newline characters. In
3297 normal use, it never will, but when playing around or testing, this error
3298 can (did) happen. To guard against this, ensure that the id contains only
3299 printing characters. */
3300
3301 if (set_id != NULL) set_id = string_printing(set_id);
3302
3303 /* For the non-OK cases, set up additional logging data if set_id
3304 is not empty. */
3305
3306 if (c != OK)
3307 {
3308 if (set_id != NULL && *set_id != 0)
3309 set_id = string_sprintf(" (set_id=%s)", set_id);
3310 else set_id = US"";
3311 }
3312
3313 /* Switch on the result */
3314
3315 switch(c)
3316 {
3317 case OK:
3318 if (au->set_id == NULL || set_id != NULL) /* Complete success */
3319 {
3320 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
3321 sender_host_authenticated = au->name;
3322 authentication_failed = FALSE;
3323 authenticated_fail_id = NULL; /* Impossible to already be set? */
3324
3325 received_protocol =
3326 (sender_host_address ? protocols : protocols_local)
3327 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3328 s = ss = US"235 Authentication succeeded";
3329 authenticated_by = au;
3330 break;
3331 }
3332
3333 /* Authentication succeeded, but we failed to expand the set_id string.
3334 Treat this as a temporary error. */
3335
3336 auth_defer_msg = expand_string_message;
3337 /* Fall through */
3338
3339 case DEFER:
3340 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3341 s = string_sprintf("435 Unable to authenticate at present%s",
3342 auth_defer_user_msg);
3343 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3344 set_id, auth_defer_msg);
3345 break;
3346
3347 case BAD64:
3348 s = ss = US"501 Invalid base64 data";
3349 break;
3350
3351 case CANCELLED:
3352 s = ss = US"501 Authentication cancelled";
3353 break;
3354
3355 case UNEXPECTED:
3356 s = ss = US"553 Initial data not expected";
3357 break;
3358
3359 case FAIL:
3360 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3361 s = US"535 Incorrect authentication data";
3362 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3363 break;
3364
3365 default:
3366 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3367 s = US"435 Internal error";
3368 ss = string_sprintf("435 Internal error%s: return %d from authentication "
3369 "check", set_id, c);
3370 break;
3371 }
3372
3373 smtp_printf("%s\r\n", s);
3374 if (c != OK)
3375 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3376 au->name, host_and_ident(FALSE), ss);
3377
3378 break; /* AUTH_CMD */
3379
3380 /* The HELO/EHLO commands are permitted to appear in the middle of a
3381 session as well as at the beginning. They have the effect of a reset in
3382 addition to their other functions. Their absence at the start cannot be
3383 taken to be an error.
3384
3385 RFC 2821 says:
3386
3387 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3388 or 502 failure replies MUST be returned as appropriate. The SMTP
3389 server MUST stay in the same state after transmitting these replies
3390 that it was in before the EHLO was received.
3391
3392 Therefore, we do not do the reset until after checking the command for
3393 acceptability. This change was made for Exim release 4.11. Previously
3394 it did the reset first. */
3395
3396 case HELO_CMD:
3397 HAD(SCH_HELO);
3398 hello = US"HELO";
3399 esmtp = FALSE;
3400 goto HELO_EHLO;
3401
3402 case EHLO_CMD:
3403 HAD(SCH_EHLO);
3404 hello = US"EHLO";
3405 esmtp = TRUE;
3406
3407 HELO_EHLO: /* Common code for HELO and EHLO */
3408 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3409 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3410
3411 /* Reject the HELO if its argument was invalid or non-existent. A
3412 successful check causes the argument to be saved in malloc store. */
3413
3414 if (!check_helo(smtp_cmd_data))
3415 {
3416 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3417
3418 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3419 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3420 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3421 string_printing(smtp_cmd_argument));
3422
3423 if (++synprot_error_count > smtp_max_synprot_errors)
3424 {
3425 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3426 "syntax or protocol errors (last command was \"%s\")",
3427 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3428 done = 1;
3429 }
3430
3431 break;
3432 }
3433
3434 /* If sender_host_unknown is true, we have got here via the -bs interface,
3435 not called from inetd. Otherwise, we are running an IP connection and the
3436 host address will be set. If the helo name is the primary name of this
3437 host and we haven't done a reverse lookup, force one now. If helo_required
3438 is set, ensure that the HELO name matches the actual host. If helo_verify
3439 is set, do the same check, but softly. */
3440
3441 if (!sender_host_unknown)
3442 {
3443 BOOL old_helo_verified = helo_verified;
3444 uschar *p = smtp_cmd_data;
3445
3446 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3447 *p = 0;
3448
3449 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3450 because otherwise the log can be confusing. */
3451
3452 if (sender_host_name == NULL &&
3453 (deliver_domain = sender_helo_name, /* set $domain */
3454 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3455 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3456 (void)host_name_lookup();
3457
3458 /* Rebuild the fullhost info to include the HELO name (and the real name
3459 if it was looked up.) */
3460
3461 host_build_sender_fullhost(); /* Rebuild */
3462 set_process_info("handling%s incoming connection from %s",
3463 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3464
3465 /* Verify if configured. This doesn't give much security, but it does
3466 make some people happy to be able to do it. If helo_required is set,
3467 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3468 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3469 now obsolescent, since the verification can now be requested selectively
3470 at ACL time. */
3471
3472 helo_verified = helo_verify_failed = FALSE;
3473 if (helo_required || helo_verify)
3474 {
3475 BOOL tempfail = !smtp_verify_helo();
3476 if (!helo_verified)
3477 {
3478 if (helo_required)
3479 {
3480 smtp_printf("%d %s argument does not match calling host\r\n",
3481 tempfail? 451 : 550, hello);
3482 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3483 tempfail? "temporarily " : "",
3484 hello, sender_helo_name, host_and_ident(FALSE));
3485 helo_verified = old_helo_verified;
3486 break; /* End of HELO/EHLO processing */
3487 }
3488 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3489 "helo_try_verify_hosts\n", hello);
3490 }
3491 }
3492 }
3493
3494 #ifdef EXPERIMENTAL_SPF
3495 /* set up SPF context */
3496 spf_init(sender_helo_name, sender_host_address);
3497 #endif
3498
3499 /* Apply an ACL check if one is defined; afterwards, recheck
3500 synchronization in case the client started sending in a delay. */
3501
3502 if (acl_smtp_helo != NULL)
3503 {
3504 rc = acl_check(ACL_WHER