RFC3461 support - MIME DSN messages. Bug 118
[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 #ifdef EXPERIMENTAL_DSN
125 static BOOL dsn_advertised;
126 #endif
127 static BOOL esmtp;
128 static BOOL helo_required = FALSE;
129 static BOOL helo_verify = FALSE;
130 static BOOL helo_seen;
131 static BOOL helo_accept_junk;
132 static BOOL count_nonmail;
133 static BOOL pipelining_advertised;
134 static BOOL rcpt_smtp_response_same;
135 static BOOL rcpt_in_progress;
136 static int nonmail_command_count;
137 static BOOL smtp_exit_function_called = 0;
138 static int synprot_error_count;
139 static int unknown_command_count;
140 static int sync_cmd_limit;
141 static int smtp_write_error = 0;
142
143 static uschar *rcpt_smtp_response;
144 static uschar *smtp_data_buffer;
145 static uschar *smtp_cmd_data;
146
147 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
148 final fields of all except AUTH are forced TRUE at the start of a new message
149 setup, to allow one of each between messages that is not counted as a nonmail
150 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
151 allow a new EHLO after starting up TLS.
152
153 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
154 counted. However, the flag is changed when AUTH is received, so that multiple
155 failing AUTHs will eventually hit the limit. After a successful AUTH, another
156 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
157 forced TRUE, to allow for the re-authentication that can happen at that point.
158
159 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
160 count of non-mail commands and possibly provoke an error. */
161
162 static smtp_cmd_list cmd_list[] = {
163 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
164 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
165 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
166 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
167 #ifdef SUPPORT_TLS
168 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
169 #endif
170
171 /* If you change anything above here, also fix the definitions below. */
172
173 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
174 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
175 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
176 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
177 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
178 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
179 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
180 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
181 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
182 };
183
184 static smtp_cmd_list *cmd_list_end =
185 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
186
187 #define CMD_LIST_RSET 0
188 #define CMD_LIST_HELO 1
189 #define CMD_LIST_EHLO 2
190 #define CMD_LIST_AUTH 3
191 #define CMD_LIST_STARTTLS 4
192
193 /* This list of names is used for performing the smtp_no_mail logging action.
194 It must be kept in step with the SCH_xxx enumerations. */
195
196 static uschar *smtp_names[] =
197 {
198 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
199 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
200 US"VRFY" };
201
202 static uschar *protocols[] = {
203 US"local-smtp", /* HELO */
204 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
205 US"local-esmtp", /* EHLO */
206 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
207 US"local-esmtpa", /* EHLO->AUTH */
208 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
209 };
210
211 #define pnormal 0
212 #define pextend 2
213 #define pcrpted 1 /* added to pextend or pnormal */
214 #define pauthed 2 /* added to pextend */
215 #define pnlocal 6 /* offset to remove "local" */
216
217 /* Sanity check and validate optional args to MAIL FROM: envelope */
218 enum {
219 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
220 #ifndef DISABLE_PRDR
221 ENV_MAIL_OPT_PRDR,
222 #endif
223 #ifdef EXPERIMENTAL_DSN
224 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
225 #endif
226 ENV_MAIL_OPT_NULL
227 };
228 typedef struct {
229 uschar * name; /* option requested during MAIL cmd */
230 int value; /* enum type */
231 BOOL need_value; /* TRUE requires value (name=value pair format)
232 FALSE is a singleton */
233 } env_mail_type_t;
234 static env_mail_type_t env_mail_type_list[] = {
235 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
236 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
237 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
238 #ifndef DISABLE_PRDR
239 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
240 #endif
241 #ifdef EXPERIMENTAL_DSN
242 { US"RET", ENV_MAIL_OPT_RET, TRUE },
243 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
244 #endif
245 { US"NULL", ENV_MAIL_OPT_NULL, FALSE }
246 };
247
248 /* When reading SMTP from a remote host, we have to use our own versions of the
249 C input-reading functions, in order to be able to flush the SMTP output only
250 when about to read more data from the socket. This is the only way to get
251 optimal performance when the client is using pipelining. Flushing for every
252 command causes a separate packet and reply packet each time; saving all the
253 responses up (when pipelining) combines them into one packet and one response.
254
255 For simplicity, these functions are used for *all* SMTP input, not only when
256 receiving over a socket. However, after setting up a secure socket (SSL), input
257 is read via the OpenSSL library, and another set of functions is used instead
258 (see tls.c).
259
260 These functions are set in the receive_getc etc. variables and called with the
261 same interface as the C functions. However, since there can only ever be
262 one incoming SMTP call, we just use a single buffer and flags. There is no need
263 to implement a complicated private FILE-like structure.*/
264
265 static uschar *smtp_inbuffer;
266 static uschar *smtp_inptr;
267 static uschar *smtp_inend;
268 static int smtp_had_eof;
269 static int smtp_had_error;
270
271
272 /*************************************************
273 * SMTP version of getc() *
274 *************************************************/
275
276 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
277 it flushes the output, and refills the buffer, with a timeout. The signal
278 handler is set appropriately by the calling function. This function is not used
279 after a connection has negotated itself into an TLS/SSL state.
280
281 Arguments: none
282 Returns: the next character or EOF
283 */
284
285 int
286 smtp_getc(void)
287 {
288 if (smtp_inptr >= smtp_inend)
289 {
290 int rc, save_errno;
291 fflush(smtp_out);
292 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
293 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
294 save_errno = errno;
295 alarm(0);
296 if (rc <= 0)
297 {
298 /* Must put the error text in fixed store, because this might be during
299 header reading, where it releases unused store above the header. */
300 if (rc < 0)
301 {
302 smtp_had_error = save_errno;
303 smtp_read_error = string_copy_malloc(
304 string_sprintf(" (error: %s)", strerror(save_errno)));
305 }
306 else smtp_had_eof = 1;
307 return EOF;
308 }
309 #ifndef DISABLE_DKIM
310 dkim_exim_verify_feed(smtp_inbuffer, rc);
311 #endif
312 smtp_inend = smtp_inbuffer + rc;
313 smtp_inptr = smtp_inbuffer;
314 }
315 return *smtp_inptr++;
316 }
317
318
319
320 /*************************************************
321 * SMTP version of ungetc() *
322 *************************************************/
323
324 /* Puts a character back in the input buffer. Only ever
325 called once.
326
327 Arguments:
328 ch the character
329
330 Returns: the character
331 */
332
333 int
334 smtp_ungetc(int ch)
335 {
336 *(--smtp_inptr) = ch;
337 return ch;
338 }
339
340
341
342
343 /*************************************************
344 * SMTP version of feof() *
345 *************************************************/
346
347 /* Tests for a previous EOF
348
349 Arguments: none
350 Returns: non-zero if the eof flag is set
351 */
352
353 int
354 smtp_feof(void)
355 {
356 return smtp_had_eof;
357 }
358
359
360
361
362 /*************************************************
363 * SMTP version of ferror() *
364 *************************************************/
365
366 /* Tests for a previous read error, and returns with errno
367 restored to what it was when the error was detected.
368
369 Arguments: none
370 Returns: non-zero if the error flag is set
371 */
372
373 int
374 smtp_ferror(void)
375 {
376 errno = smtp_had_error;
377 return smtp_had_error;
378 }
379
380
381
382 /*************************************************
383 * Test for characters in the SMTP buffer *
384 *************************************************/
385
386 /* Used at the end of a message
387
388 Arguments: none
389 Returns: TRUE/FALSE
390 */
391
392 BOOL
393 smtp_buffered(void)
394 {
395 return smtp_inptr < smtp_inend;
396 }
397
398
399
400 /*************************************************
401 * Write formatted string to SMTP channel *
402 *************************************************/
403
404 /* This is a separate function so that we don't have to repeat everything for
405 TLS support or debugging. It is global so that the daemon and the
406 authentication functions can use it. It does not return any error indication,
407 because major problems such as dropped connections won't show up till an output
408 flush for non-TLS connections. The smtp_fflush() function is available for
409 checking that: for convenience, TLS output errors are remembered here so that
410 they are also picked up later by smtp_fflush().
411
412 Arguments:
413 format format string
414 ... optional arguments
415
416 Returns: nothing
417 */
418
419 void
420 smtp_printf(const char *format, ...)
421 {
422 va_list ap;
423
424 va_start(ap, format);
425 smtp_vprintf(format, ap);
426 va_end(ap);
427 }
428
429 /* This is split off so that verify.c:respond_printf() can, in effect, call
430 smtp_printf(), bearing in mind that in C a vararg function can't directly
431 call another vararg function, only a function which accepts a va_list. */
432
433 void
434 smtp_vprintf(const char *format, va_list ap)
435 {
436 BOOL yield;
437
438 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
439
440 DEBUG(D_receive)
441 {
442 void *reset_point = store_get(0);
443 uschar *msg_copy, *cr, *end;
444 msg_copy = string_copy(big_buffer);
445 end = msg_copy + Ustrlen(msg_copy);
446 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
447 memmove(cr, cr + 1, (end--) - cr);
448 debug_printf("SMTP>> %s", msg_copy);
449 store_reset(reset_point);
450 }
451
452 if (!yield)
453 {
454 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
455 smtp_closedown(US"Unexpected error");
456 exim_exit(EXIT_FAILURE);
457 }
458
459 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
460 have had the same. Note: this code is also present in smtp_respond(). It would
461 be tidier to have it only in one place, but when it was added, it was easier to
462 do it that way, so as not to have to mess with the code for the RCPT command,
463 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
464
465 if (rcpt_in_progress)
466 {
467 if (rcpt_smtp_response == NULL)
468 rcpt_smtp_response = string_copy(big_buffer);
469 else if (rcpt_smtp_response_same &&
470 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
471 rcpt_smtp_response_same = FALSE;
472 rcpt_in_progress = FALSE;
473 }
474
475 /* Now write the string */
476
477 #ifdef SUPPORT_TLS
478 if (tls_in.active >= 0)
479 {
480 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
481 smtp_write_error = -1;
482 }
483 else
484 #endif
485
486 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
487 }
488
489
490
491 /*************************************************
492 * Flush SMTP out and check for error *
493 *************************************************/
494
495 /* This function isn't currently used within Exim (it detects errors when it
496 tries to read the next SMTP input), but is available for use in local_scan().
497 For non-TLS connections, it flushes the output and checks for errors. For
498 TLS-connections, it checks for a previously-detected TLS write error.
499
500 Arguments: none
501 Returns: 0 for no error; -1 after an error
502 */
503
504 int
505 smtp_fflush(void)
506 {
507 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
508 return smtp_write_error;
509 }
510
511
512
513 /*************************************************
514 * SMTP command read timeout *
515 *************************************************/
516
517 /* Signal handler for timing out incoming SMTP commands. This attempts to
518 finish off tidily.
519
520 Argument: signal number (SIGALRM)
521 Returns: nothing
522 */
523
524 static void
525 command_timeout_handler(int sig)
526 {
527 sig = sig; /* Keep picky compilers happy */
528 log_write(L_lost_incoming_connection,
529 LOG_MAIN, "SMTP command timeout on%s connection from %s",
530 (tls_in.active >= 0)? " TLS" : "",
531 host_and_ident(FALSE));
532 if (smtp_batched_input)
533 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
534 smtp_notquit_exit(US"command-timeout", US"421",
535 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
536 exim_exit(EXIT_FAILURE);
537 }
538
539
540
541 /*************************************************
542 * SIGTERM received *
543 *************************************************/
544
545 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
546
547 Argument: signal number (SIGTERM)
548 Returns: nothing
549 */
550
551 static void
552 command_sigterm_handler(int sig)
553 {
554 sig = sig; /* Keep picky compilers happy */
555 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
556 if (smtp_batched_input)
557 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
558 smtp_notquit_exit(US"signal-exit", US"421",
559 US"%s: Service not available - closing connection", smtp_active_hostname);
560 exim_exit(EXIT_FAILURE);
561 }
562
563
564
565
566 #ifdef EXPERIMENTAL_PROXY
567 /*************************************************
568 * Restore socket timeout to previous value *
569 *************************************************/
570 /* If the previous value was successfully retrieved, restore
571 it before returning control to the non-proxy routines
572
573 Arguments: fd - File descriptor for input
574 get_ok - Successfully retrieved previous values
575 tvtmp - Time struct with previous values
576 vslen - Length of time struct
577 Returns: none
578 */
579 static void
580 restore_socket_timeout(int fd, int get_ok, struct timeval tvtmp, socklen_t vslen)
581 {
582 if (get_ok == 0)
583 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp, vslen);
584 }
585
586 /*************************************************
587 * Check if host is required proxy host *
588 *************************************************/
589 /* The function determines if inbound host will be a regular smtp host
590 or if it is configured that it must use Proxy Protocol.
591
592 Arguments: none
593 Returns: bool
594 */
595
596 static BOOL
597 check_proxy_protocol_host()
598 {
599 int rc;
600 /* Cannot configure local connection as a proxy inbound */
601 if (sender_host_address == NULL) return proxy_session;
602
603 rc = verify_check_this_host(&proxy_required_hosts, NULL, NULL,
604 sender_host_address, NULL);
605 if (rc == OK)
606 {
607 DEBUG(D_receive)
608 debug_printf("Detected proxy protocol configured host\n");
609 proxy_session = TRUE;
610 }
611 return proxy_session;
612 }
613
614
615 /*************************************************
616 * Setup host for proxy protocol *
617 *************************************************/
618 /* The function configures the connection based on a header from the
619 inbound host to use Proxy Protocol. The specification is very exact
620 so exit with an error if do not find the exact required pieces. This
621 includes an incorrect number of spaces separating args.
622
623 Arguments: none
624 Returns: int
625 */
626
627 static BOOL
628 setup_proxy_protocol_host()
629 {
630 union {
631 struct {
632 uschar line[108];
633 } v1;
634 struct {
635 uschar sig[12];
636 uint8_t ver_cmd;
637 uint8_t fam;
638 uint16_t len;
639 union {
640 struct { /* TCP/UDP over IPv4, len = 12 */
641 uint32_t src_addr;
642 uint32_t dst_addr;
643 uint16_t src_port;
644 uint16_t dst_port;
645 } ip4;
646 struct { /* TCP/UDP over IPv6, len = 36 */
647 uint8_t src_addr[16];
648 uint8_t dst_addr[16];
649 uint16_t src_port;
650 uint16_t dst_port;
651 } ip6;
652 struct { /* AF_UNIX sockets, len = 216 */
653 uschar src_addr[108];
654 uschar dst_addr[108];
655 } unx;
656 } addr;
657 } v2;
658 } hdr;
659
660 /* Temp variables used in PPv2 address:port parsing */
661 uint16_t tmpport;
662 char tmpip[INET_ADDRSTRLEN];
663 struct sockaddr_in tmpaddr;
664 char tmpip6[INET6_ADDRSTRLEN];
665 struct sockaddr_in6 tmpaddr6;
666
667 int get_ok = 0;
668 int size, ret, fd;
669 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
670 uschar *iptype; /* To display debug info */
671 struct timeval tv;
672 socklen_t vslen = 0;
673 struct timeval tvtmp;
674
675 vslen = sizeof(struct timeval);
676
677 fd = fileno(smtp_in);
678
679 /* Save current socket timeout values */
680 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tvtmp,
681 &vslen);
682
683 /* Proxy Protocol host must send header within a short time
684 (default 3 seconds) or it's considered invalid */
685 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
686 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
687 setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
688 sizeof(struct timeval));
689
690 do
691 {
692 /* The inbound host was declared to be a Proxy Protocol host, so
693 don't do a PEEK into the data, actually slurp it up. */
694 ret = recv(fd, &hdr, sizeof(hdr), 0);
695 }
696 while (ret == -1 && errno == EINTR);
697
698 if (ret == -1)
699 {
700 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
701 return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
702 }
703
704 if (ret >= 16 &&
705 memcmp(&hdr.v2, v2sig, 12) == 0)
706 {
707 uint8_t ver, cmd;
708
709 /* May 2014: haproxy combined the version and command into one byte to
710 allow two full bytes for the length field in order to proxy SSL
711 connections. SSL Proxy is not supported in this version of Exim, but
712 must still seperate values here. */
713 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
714 cmd = (hdr.v2.ver_cmd & 0x0f);
715
716 if (ver != 0x02)
717 {
718 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
719 goto proxyfail;
720 }
721 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
722 /* The v2 header will always be 16 bytes per the spec. */
723 size = 16 + hdr.v2.len;
724 if (ret < size)
725 {
726 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
727 ret, size);
728 goto proxyfail;
729 }
730 switch (cmd)
731 {
732 case 0x01: /* PROXY command */
733 switch (hdr.v2.fam)
734 {
735 case 0x11: /* TCPv4 address type */
736 iptype = US"IPv4";
737 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
738 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
739 if (!string_is_ip_address(US tmpip,NULL))
740 {
741 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
742 return ERRNO_PROXYFAIL;
743 }
744 proxy_host_address = sender_host_address;
745 sender_host_address = string_copy(US tmpip);
746 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
747 proxy_host_port = sender_host_port;
748 sender_host_port = tmpport;
749 /* Save dest ip/port */
750 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
751 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
752 if (!string_is_ip_address(US tmpip,NULL))
753 {
754 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
755 return ERRNO_PROXYFAIL;
756 }
757 proxy_target_address = string_copy(US tmpip);
758 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
759 proxy_target_port = tmpport;
760 goto done;
761 case 0x21: /* TCPv6 address type */
762 iptype = US"IPv6";
763 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
764 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
765 if (!string_is_ip_address(US tmpip6,NULL))
766 {
767 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
768 return ERRNO_PROXYFAIL;
769 }
770 proxy_host_address = sender_host_address;
771 sender_host_address = string_copy(US tmpip6);
772 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
773 proxy_host_port = sender_host_port;
774 sender_host_port = tmpport;
775 /* Save dest ip/port */
776 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
777 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
778 if (!string_is_ip_address(US tmpip6,NULL))
779 {
780 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
781 return ERRNO_PROXYFAIL;
782 }
783 proxy_target_address = string_copy(US tmpip6);
784 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
785 proxy_target_port = tmpport;
786 goto done;
787 default:
788 DEBUG(D_receive)
789 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
790 hdr.v2.fam);
791 goto proxyfail;
792 }
793 /* Unsupported protocol, keep local connection address */
794 break;
795 case 0x00: /* LOCAL command */
796 /* Keep local connection address for LOCAL */
797 break;
798 default:
799 DEBUG(D_receive)
800 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
801 goto proxyfail;
802 }
803 }
804 else if (ret >= 8 &&
805 memcmp(hdr.v1.line, "PROXY", 5) == 0)
806 {
807 uschar *p = string_copy(hdr.v1.line);
808 uschar *end = memchr(p, '\r', ret - 1);
809 uschar *sp; /* Utility variables follow */
810 int tmp_port;
811 char *endc;
812
813 if (!end || end[1] != '\n')
814 {
815 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
816 goto proxyfail;
817 }
818 *end = '\0'; /* Terminate the string */
819 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
820 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
821 /* Step through the string looking for the required fields. Ensure
822 strict adherance to required formatting, exit for any error. */
823 p += 5;
824 if (!isspace(*(p++)))
825 {
826 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
827 goto proxyfail;
828 }
829 if (!Ustrncmp(p, CCS"TCP4", 4))
830 iptype = US"IPv4";
831 else if (!Ustrncmp(p,CCS"TCP6", 4))
832 iptype = US"IPv6";
833 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
834 {
835 iptype = US"Unknown";
836 goto done;
837 }
838 else
839 {
840 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
841 goto proxyfail;
842 }
843
844 p += Ustrlen(iptype);
845 if (!isspace(*(p++)))
846 {
847 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
848 goto proxyfail;
849 }
850 /* Find the end of the arg */
851 if ((sp = Ustrchr(p, ' ')) == NULL)
852 {
853 DEBUG(D_receive)
854 debug_printf("Did not find proxied src %s\n", iptype);
855 goto proxyfail;
856 }
857 *sp = '\0';
858 if(!string_is_ip_address(p,NULL))
859 {
860 DEBUG(D_receive)
861 debug_printf("Proxied src arg is not an %s address\n", iptype);
862 goto proxyfail;
863 }
864 proxy_host_address = sender_host_address;
865 sender_host_address = p;
866 p = sp + 1;
867 if ((sp = Ustrchr(p, ' ')) == NULL)
868 {
869 DEBUG(D_receive)
870 debug_printf("Did not find proxy dest %s\n", iptype);
871 goto proxyfail;
872 }
873 *sp = '\0';
874 if(!string_is_ip_address(p,NULL))
875 {
876 DEBUG(D_receive)
877 debug_printf("Proxy dest arg is not an %s address\n", iptype);
878 goto proxyfail;
879 }
880 proxy_target_address = p;
881 p = sp + 1;
882 if ((sp = Ustrchr(p, ' ')) == NULL)
883 {
884 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
885 goto proxyfail;
886 }
887 *sp = '\0';
888 tmp_port = strtol(CCS p,&endc,10);
889 if (*endc || tmp_port == 0)
890 {
891 DEBUG(D_receive)
892 debug_printf("Proxied src port '%s' not an integer\n", p);
893 goto proxyfail;
894 }
895 proxy_host_port = sender_host_port;
896 sender_host_port = tmp_port;
897 p = sp + 1;
898 if ((sp = Ustrchr(p, '\0')) == NULL)
899 {
900 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
901 goto proxyfail;
902 }
903 tmp_port = strtol(CCS p,&endc,10);
904 if (*endc || tmp_port == 0)
905 {
906 DEBUG(D_receive)
907 debug_printf("Proxy dest port '%s' not an integer\n", p);
908 goto proxyfail;
909 }
910 proxy_target_port = tmp_port;
911 /* Already checked for /r /n above. Good V1 header received. */
912 goto done;
913 }
914 else
915 {
916 /* Wrong protocol */
917 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
918 goto proxyfail;
919 }
920
921 proxyfail:
922 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
923 /* Don't flush any potential buffer contents. Any input should cause a
924 synchronization failure */
925 return FALSE;
926
927 done:
928 restore_socket_timeout(fd, get_ok, tvtmp, vslen);
929 DEBUG(D_receive)
930 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
931 return proxy_session;
932 }
933 #endif
934
935 /*************************************************
936 * Read one command line *
937 *************************************************/
938
939 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
940 There are sites that don't do this, and in any case internal SMTP probably
941 should check only for LF. Consequently, we check here for LF only. The line
942 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
943 an unknown command. The command is read into the global smtp_cmd_buffer so that
944 it is available via $smtp_command.
945
946 The character reading routine sets up a timeout for each block actually read
947 from the input (which may contain more than one command). We set up a special
948 signal handler that closes down the session on a timeout. Control does not
949 return when it runs.
950
951 Arguments:
952 check_sync if TRUE, check synchronization rules if global option is TRUE
953
954 Returns: a code identifying the command (enumerated above)
955 */
956
957 static int
958 smtp_read_command(BOOL check_sync)
959 {
960 int c;
961 int ptr = 0;
962 smtp_cmd_list *p;
963 BOOL hadnull = FALSE;
964
965 os_non_restarting_signal(SIGALRM, command_timeout_handler);
966
967 while ((c = (receive_getc)()) != '\n' && c != EOF)
968 {
969 if (ptr >= smtp_cmd_buffer_size)
970 {
971 os_non_restarting_signal(SIGALRM, sigalrm_handler);
972 return OTHER_CMD;
973 }
974 if (c == 0)
975 {
976 hadnull = TRUE;
977 c = '?';
978 }
979 smtp_cmd_buffer[ptr++] = c;
980 }
981
982 receive_linecount++; /* For BSMTP errors */
983 os_non_restarting_signal(SIGALRM, sigalrm_handler);
984
985 /* If hit end of file, return pseudo EOF command. Whether we have a
986 part-line already read doesn't matter, since this is an error state. */
987
988 if (c == EOF) return EOF_CMD;
989
990 /* Remove any CR and white space at the end of the line, and terminate the
991 string. */
992
993 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
994 smtp_cmd_buffer[ptr] = 0;
995
996 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
997
998 /* NULLs are not allowed in SMTP commands */
999
1000 if (hadnull) return BADCHAR_CMD;
1001
1002 /* Scan command list and return identity, having set the data pointer
1003 to the start of the actual data characters. Check for SMTP synchronization
1004 if required. */
1005
1006 for (p = cmd_list; p < cmd_list_end; p++)
1007 {
1008 #ifdef EXPERIMENTAL_PROXY
1009 /* Only allow QUIT command if Proxy Protocol parsing failed */
1010 if (proxy_session && proxy_session_failed)
1011 {
1012 if (p->cmd != QUIT_CMD)
1013 continue;
1014 }
1015 #endif
1016 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
1017 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
1018 smtp_cmd_buffer[p->len] == 0 ||
1019 smtp_cmd_buffer[p->len] == ' '))
1020 {
1021 if (smtp_inptr < smtp_inend && /* Outstanding input */
1022 p->cmd < sync_cmd_limit && /* Command should sync */
1023 check_sync && /* Local flag set */
1024 smtp_enforce_sync && /* Global flag set */
1025 sender_host_address != NULL && /* Not local input */
1026 !sender_host_notsocket) /* Really is a socket */
1027 return BADSYN_CMD;
1028
1029 /* The variables $smtp_command and $smtp_command_argument point into the
1030 unmodified input buffer. A copy of the latter is taken for actual
1031 processing, so that it can be chopped up into separate parts if necessary,
1032 for example, when processing a MAIL command options such as SIZE that can
1033 follow the sender address. */
1034
1035 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1036 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1037 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1038 smtp_cmd_data = smtp_data_buffer;
1039
1040 /* Count non-mail commands from those hosts that are controlled in this
1041 way. The default is all hosts. We don't waste effort checking the list
1042 until we get a non-mail command, but then cache the result to save checking
1043 again. If there's a DEFER while checking the host, assume it's in the list.
1044
1045 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1046 start of each incoming message by fiddling with the value in the table. */
1047
1048 if (!p->is_mail_cmd)
1049 {
1050 if (count_nonmail == TRUE_UNSET) count_nonmail =
1051 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1052 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1053 return TOO_MANY_NONMAIL_CMD;
1054 }
1055
1056 /* If there is data for a command that does not expect it, generate the
1057 error here. */
1058
1059 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1060 }
1061 }
1062
1063 #ifdef EXPERIMENTAL_PROXY
1064 /* Only allow QUIT command if Proxy Protocol parsing failed */
1065 if (proxy_session && proxy_session_failed)
1066 return PROXY_FAIL_IGNORE_CMD;
1067 #endif
1068
1069 /* Enforce synchronization for unknown commands */
1070
1071 if (smtp_inptr < smtp_inend && /* Outstanding input */
1072 check_sync && /* Local flag set */
1073 smtp_enforce_sync && /* Global flag set */
1074 sender_host_address != NULL && /* Not local input */
1075 !sender_host_notsocket) /* Really is a socket */
1076 return BADSYN_CMD;
1077
1078 return OTHER_CMD;
1079 }
1080
1081
1082
1083 /*************************************************
1084 * Recheck synchronization *
1085 *************************************************/
1086
1087 /* Synchronization checks can never be perfect because a packet may be on its
1088 way but not arrived when the check is done. Such checks can in any case only be
1089 done when TLS is not in use. Normally, the checks happen when commands are
1090 read: Exim ensures that there is no more input in the input buffer. In normal
1091 cases, the response to the command will be fast, and there is no further check.
1092
1093 However, for some commands an ACL is run, and that can include delays. In those
1094 cases, it is useful to do another check on the input just before sending the
1095 response. This also applies at the start of a connection. This function does
1096 that check by means of the select() function, as long as the facility is not
1097 disabled or inappropriate. A failure of select() is ignored.
1098
1099 When there is unwanted input, we read it so that it appears in the log of the
1100 error.
1101
1102 Arguments: none
1103 Returns: TRUE if all is well; FALSE if there is input pending
1104 */
1105
1106 static BOOL
1107 check_sync(void)
1108 {
1109 int fd, rc;
1110 fd_set fds;
1111 struct timeval tzero;
1112
1113 if (!smtp_enforce_sync || sender_host_address == NULL ||
1114 sender_host_notsocket || tls_in.active >= 0)
1115 return TRUE;
1116
1117 fd = fileno(smtp_in);
1118 FD_ZERO(&fds);
1119 FD_SET(fd, &fds);
1120 tzero.tv_sec = 0;
1121 tzero.tv_usec = 0;
1122 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1123
1124 if (rc <= 0) return TRUE; /* Not ready to read */
1125 rc = smtp_getc();
1126 if (rc < 0) return TRUE; /* End of file or error */
1127
1128 smtp_ungetc(rc);
1129 rc = smtp_inend - smtp_inptr;
1130 if (rc > 150) rc = 150;
1131 smtp_inptr[rc] = 0;
1132 return FALSE;
1133 }
1134
1135
1136
1137 /*************************************************
1138 * Forced closedown of call *
1139 *************************************************/
1140
1141 /* This function is called from log.c when Exim is dying because of a serious
1142 disaster, and also from some other places. If an incoming non-batched SMTP
1143 channel is open, it swallows the rest of the incoming message if in the DATA
1144 phase, sends the reply string, and gives an error to all subsequent commands
1145 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1146 smtp_in.
1147
1148 Arguments:
1149 message SMTP reply string to send, excluding the code
1150
1151 Returns: nothing
1152 */
1153
1154 void
1155 smtp_closedown(uschar *message)
1156 {
1157 if (smtp_in == NULL || smtp_batched_input) return;
1158 receive_swallow_smtp();
1159 smtp_printf("421 %s\r\n", message);
1160
1161 for (;;)
1162 {
1163 switch(smtp_read_command(FALSE))
1164 {
1165 case EOF_CMD:
1166 return;
1167
1168 case QUIT_CMD:
1169 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1170 mac_smtp_fflush();
1171 return;
1172
1173 case RSET_CMD:
1174 smtp_printf("250 Reset OK\r\n");
1175 break;
1176
1177 default:
1178 smtp_printf("421 %s\r\n", message);
1179 break;
1180 }
1181 }
1182 }
1183
1184
1185
1186
1187 /*************************************************
1188 * Set up connection info for logging *
1189 *************************************************/
1190
1191 /* This function is called when logging information about an SMTP connection.
1192 It sets up appropriate source information, depending on the type of connection.
1193 If sender_fullhost is NULL, we are at a very early stage of the connection;
1194 just use the IP address.
1195
1196 Argument: none
1197 Returns: a string describing the connection
1198 */
1199
1200 uschar *
1201 smtp_get_connection_info(void)
1202 {
1203 uschar *hostname = (sender_fullhost == NULL)?
1204 sender_host_address : sender_fullhost;
1205
1206 if (host_checking)
1207 return string_sprintf("SMTP connection from %s", hostname);
1208
1209 if (sender_host_unknown || sender_host_notsocket)
1210 return string_sprintf("SMTP connection from %s", sender_ident);
1211
1212 if (is_inetd)
1213 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1214
1215 if ((log_extra_selector & LX_incoming_interface) != 0 &&
1216 interface_address != NULL)
1217 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1218 interface_address, interface_port);
1219
1220 return string_sprintf("SMTP connection from %s", hostname);
1221 }
1222
1223
1224
1225 #ifdef SUPPORT_TLS
1226 /* Append TLS-related information to a log line
1227
1228 Arguments:
1229 s String under construction: allocated string to extend, or NULL
1230 sizep Pointer to current allocation size (update on return), or NULL
1231 ptrp Pointer to index for new entries in string (update on return), or NULL
1232
1233 Returns: Allocated string or NULL
1234 */
1235 static uschar *
1236 s_tlslog(uschar * s, int * sizep, int * ptrp)
1237 {
1238 int size = sizep ? *sizep : 0;
1239 int ptr = ptrp ? *ptrp : 0;
1240
1241 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_in.cipher != NULL)
1242 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1243 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
1244 tls_in.cipher != NULL)
1245 s = string_append(s, &size, &ptr, 2, US" CV=",
1246 tls_in.certificate_verified? "yes":"no");
1247 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_in.peerdn != NULL)
1248 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1249 string_printing(tls_in.peerdn), US"\"");
1250 if ((log_extra_selector & LX_tls_sni) != 0 && tls_in.sni != NULL)
1251 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1252 string_printing(tls_in.sni), US"\"");
1253
1254 if (s)
1255 {
1256 s[ptr] = '\0';
1257 if (sizep) *sizep = size;
1258 if (ptrp) *ptrp = ptr;
1259 }
1260 return s;
1261 }
1262 #endif
1263
1264 /*************************************************
1265 * Log lack of MAIL if so configured *
1266 *************************************************/
1267
1268 /* This function is called when an SMTP session ends. If the log selector
1269 smtp_no_mail is set, write a log line giving some details of what has happened
1270 in the SMTP session.
1271
1272 Arguments: none
1273 Returns: nothing
1274 */
1275
1276 void
1277 smtp_log_no_mail(void)
1278 {
1279 int size, ptr, i;
1280 uschar *s, *sep;
1281
1282 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
1283 return;
1284
1285 s = NULL;
1286 size = ptr = 0;
1287
1288 if (sender_host_authenticated != NULL)
1289 {
1290 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1291 if (authenticated_id != NULL)
1292 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1293 }
1294
1295 #ifdef SUPPORT_TLS
1296 s = s_tlslog(s, &size, &ptr);
1297 #endif
1298
1299 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1300 US" C=..." : US" C=";
1301 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1302 {
1303 if (smtp_connection_had[i] != SCH_NONE)
1304 {
1305 s = string_append(s, &size, &ptr, 2, sep,
1306 smtp_names[smtp_connection_had[i]]);
1307 sep = US",";
1308 }
1309 }
1310
1311 for (i = 0; i < smtp_ch_index; i++)
1312 {
1313 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1314 sep = US",";
1315 }
1316
1317 if (s != NULL) s[ptr] = 0; else s = US"";
1318 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1319 host_and_ident(FALSE),
1320 readconf_printtime(time(NULL) - smtp_connection_start), s);
1321 }
1322
1323
1324
1325 /*************************************************
1326 * Check HELO line and set sender_helo_name *
1327 *************************************************/
1328
1329 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1330 the domain name of the sending host, or an ip literal in square brackets. The
1331 arrgument is placed in sender_helo_name, which is in malloc store, because it
1332 must persist over multiple incoming messages. If helo_accept_junk is set, this
1333 host is permitted to send any old junk (needed for some broken hosts).
1334 Otherwise, helo_allow_chars can be used for rogue characters in general
1335 (typically people want to let in underscores).
1336
1337 Argument:
1338 s the data portion of the line (already past any white space)
1339
1340 Returns: TRUE or FALSE
1341 */
1342
1343 static BOOL
1344 check_helo(uschar *s)
1345 {
1346 uschar *start = s;
1347 uschar *end = s + Ustrlen(s);
1348 BOOL yield = helo_accept_junk;
1349
1350 /* Discard any previous helo name */
1351
1352 if (sender_helo_name != NULL)
1353 {
1354 store_free(sender_helo_name);
1355 sender_helo_name = NULL;
1356 }
1357
1358 /* Skip tests if junk is permitted. */
1359
1360 if (!yield)
1361 {
1362 /* Allow the new standard form for IPv6 address literals, namely,
1363 [IPv6:....], and because someone is bound to use it, allow an equivalent
1364 IPv4 form. Allow plain addresses as well. */
1365
1366 if (*s == '[')
1367 {
1368 if (end[-1] == ']')
1369 {
1370 end[-1] = 0;
1371 if (strncmpic(s, US"[IPv6:", 6) == 0)
1372 yield = (string_is_ip_address(s+6, NULL) == 6);
1373 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1374 yield = (string_is_ip_address(s+6, NULL) == 4);
1375 else
1376 yield = (string_is_ip_address(s+1, NULL) != 0);
1377 end[-1] = ']';
1378 }
1379 }
1380
1381 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1382 that have been configured (usually underscore - sigh). */
1383
1384 else if (*s != 0)
1385 {
1386 yield = TRUE;
1387 while (*s != 0)
1388 {
1389 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1390 Ustrchr(helo_allow_chars, *s) == NULL)
1391 {
1392 yield = FALSE;
1393 break;
1394 }
1395 s++;
1396 }
1397 }
1398 }
1399
1400 /* Save argument if OK */
1401
1402 if (yield) sender_helo_name = string_copy_malloc(start);
1403 return yield;
1404 }
1405
1406
1407
1408
1409
1410 /*************************************************
1411 * Extract SMTP command option *
1412 *************************************************/
1413
1414 /* This function picks the next option setting off the end of smtp_cmd_data. It
1415 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1416 things that can appear there.
1417
1418 Arguments:
1419 name point this at the name
1420 value point this at the data string
1421
1422 Returns: TRUE if found an option
1423 */
1424
1425 static BOOL
1426 extract_option(uschar **name, uschar **value)
1427 {
1428 uschar *n;
1429 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1430 while (isspace(*v)) v--;
1431 v[1] = 0;
1432 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1433
1434 n = v;
1435 if (*v == '=')
1436 {
1437 while(isalpha(n[-1])) n--;
1438 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1439 if (!isspace(n[-1])) return FALSE;
1440 n[-1] = 0;
1441 }
1442 else
1443 {
1444 n++;
1445 if (v == smtp_cmd_data) return FALSE;
1446 }
1447 *v++ = 0;
1448 *name = n;
1449 *value = v;
1450 return TRUE;
1451 }
1452
1453
1454
1455
1456
1457 /*************************************************
1458 * Reset for new message *
1459 *************************************************/
1460
1461 /* This function is called whenever the SMTP session is reset from
1462 within either of the setup functions.
1463
1464 Argument: the stacking pool storage reset point
1465 Returns: nothing
1466 */
1467
1468 static void
1469 smtp_reset(void *reset_point)
1470 {
1471 store_reset(reset_point);
1472 recipients_list = NULL;
1473 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1474 raw_recipients_count = recipients_count = recipients_list_max = 0;
1475 cancel_cutthrough_connection("smtp reset");
1476 message_linecount = 0;
1477 message_size = -1;
1478 acl_added_headers = NULL;
1479 acl_removed_headers = NULL;
1480 queue_only_policy = FALSE;
1481 rcpt_smtp_response = NULL;
1482 rcpt_smtp_response_same = TRUE;
1483 rcpt_in_progress = FALSE;
1484 deliver_freeze = FALSE; /* Can be set by ACL */
1485 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1486 fake_response = OK; /* Can be set by ACL */
1487 #ifdef WITH_CONTENT_SCAN
1488 no_mbox_unspool = FALSE; /* Can be set by ACL */
1489 #endif
1490 submission_mode = FALSE; /* Can be set by ACL */
1491 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1492 active_local_from_check = local_from_check; /* Can be set by ACL */
1493 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1494 sender_address = NULL;
1495 submission_name = NULL; /* Can be set by ACL */
1496 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1497 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1498 sender_verified_list = NULL; /* No senders verified */
1499 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1500 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1501
1502 #ifdef EXPERIMENTAL_DSN
1503 /* Reset the DSN flags */
1504 dsn_ret = 0;
1505 dsn_envid = NULL;
1506 #endif
1507
1508 authenticated_sender = NULL;
1509 #ifdef EXPERIMENTAL_BRIGHTMAIL
1510 bmi_run = 0;
1511 bmi_verdicts = NULL;
1512 #endif
1513 #ifndef DISABLE_DKIM
1514 dkim_signers = NULL;
1515 dkim_disable_verify = FALSE;
1516 dkim_collect_input = FALSE;
1517 #endif
1518 #ifdef EXPERIMENTAL_SPF
1519 spf_header_comment = NULL;
1520 spf_received = NULL;
1521 spf_result = NULL;
1522 spf_smtp_comment = NULL;
1523 #endif
1524 body_linecount = body_zerocount = 0;
1525
1526 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1527 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1528 /* Note that ratelimiters_conn persists across resets. */
1529
1530 /* Reset message ACL variables */
1531
1532 acl_var_m = NULL;
1533
1534 /* The message body variables use malloc store. They may be set if this is
1535 not the first message in an SMTP session and the previous message caused them
1536 to be referenced in an ACL. */
1537
1538 if (message_body != NULL)
1539 {
1540 store_free(message_body);
1541 message_body = NULL;
1542 }
1543
1544 if (message_body_end != NULL)
1545 {
1546 store_free(message_body_end);
1547 message_body_end = NULL;
1548 }
1549
1550 /* Warning log messages are also saved in malloc store. They are saved to avoid
1551 repetition in the same message, but it seems right to repeat them for different
1552 messages. */
1553
1554 while (acl_warn_logged != NULL)
1555 {
1556 string_item *this = acl_warn_logged;
1557 acl_warn_logged = acl_warn_logged->next;
1558 store_free(this);
1559 }
1560 }
1561
1562
1563
1564
1565
1566 /*************************************************
1567 * Initialize for incoming batched SMTP message *
1568 *************************************************/
1569
1570 /* This function is called from smtp_setup_msg() in the case when
1571 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1572 of messages in one file with SMTP commands between them. All errors must be
1573 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1574 relevant. After an error on a sender, or an invalid recipient, the remainder
1575 of the message is skipped. The value of received_protocol is already set.
1576
1577 Argument: none
1578 Returns: > 0 message successfully started (reached DATA)
1579 = 0 QUIT read or end of file reached
1580 < 0 should not occur
1581 */
1582
1583 static int
1584 smtp_setup_batch_msg(void)
1585 {
1586 int done = 0;
1587 void *reset_point = store_get(0);
1588
1589 /* Save the line count at the start of each transaction - single commands
1590 like HELO and RSET count as whole transactions. */
1591
1592 bsmtp_transaction_linecount = receive_linecount;
1593
1594 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1595
1596 smtp_reset(reset_point); /* Reset for start of message */
1597
1598 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1599 value. The values are 2 larger than the required yield of the function. */
1600
1601 while (done <= 0)
1602 {
1603 uschar *errmess;
1604 uschar *recipient = NULL;
1605 int start, end, sender_domain, recipient_domain;
1606
1607 switch(smtp_read_command(FALSE))
1608 {
1609 /* The HELO/EHLO commands set sender_address_helo if they have
1610 valid data; otherwise they are ignored, except that they do
1611 a reset of the state. */
1612
1613 case HELO_CMD:
1614 case EHLO_CMD:
1615
1616 check_helo(smtp_cmd_data);
1617 /* Fall through */
1618
1619 case RSET_CMD:
1620 smtp_reset(reset_point);
1621 bsmtp_transaction_linecount = receive_linecount;
1622 break;
1623
1624
1625 /* The MAIL FROM command requires an address as an operand. All we
1626 do here is to parse it for syntactic correctness. The form "<>" is
1627 a special case which converts into an empty string. The start/end
1628 pointers in the original are not used further for this address, as
1629 it is the canonical extracted address which is all that is kept. */
1630
1631 case MAIL_CMD:
1632 if (sender_address != NULL)
1633 /* The function moan_smtp_batch() does not return. */
1634 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1635
1636 if (smtp_cmd_data[0] == 0)
1637 /* The function moan_smtp_batch() does not return. */
1638 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1639
1640 /* Reset to start of message */
1641
1642 smtp_reset(reset_point);
1643
1644 /* Apply SMTP rewrite */
1645
1646 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1647 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1648 US"", global_rewrite_rules) : smtp_cmd_data;
1649
1650 /* Extract the address; the TRUE flag allows <> as valid */
1651
1652 raw_sender =
1653 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1654 TRUE);
1655
1656 if (raw_sender == NULL)
1657 /* The function moan_smtp_batch() does not return. */
1658 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1659
1660 sender_address = string_copy(raw_sender);
1661
1662 /* Qualify unqualified sender addresses if permitted to do so. */
1663
1664 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1665 {
1666 if (allow_unqualified_sender)
1667 {
1668 sender_address = rewrite_address_qualify(sender_address, FALSE);
1669 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1670 "and rewritten\n", raw_sender);
1671 }
1672 /* The function moan_smtp_batch() does not return. */
1673 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1674 "a domain");
1675 }
1676 break;
1677
1678
1679 /* The RCPT TO command requires an address as an operand. All we do
1680 here is to parse it for syntactic correctness. There may be any number
1681 of RCPT TO commands, specifying multiple senders. We build them all into
1682 a data structure that is in argc/argv format. The start/end values
1683 given by parse_extract_address are not used, as we keep only the
1684 extracted address. */
1685
1686 case RCPT_CMD:
1687 if (sender_address == NULL)
1688 /* The function moan_smtp_batch() does not return. */
1689 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1690
1691 if (smtp_cmd_data[0] == 0)
1692 /* The function moan_smtp_batch() does not return. */
1693 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1694
1695 /* Check maximum number allowed */
1696
1697 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1698 /* The function moan_smtp_batch() does not return. */
1699 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1700 recipients_max_reject? "552": "452");
1701
1702 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1703 recipient address */
1704
1705 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1706 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1707 global_rewrite_rules) : smtp_cmd_data;
1708
1709 /* rfc821_domains = TRUE; << no longer needed */
1710 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1711 &recipient_domain, FALSE);
1712 /* rfc821_domains = FALSE; << no longer needed */
1713
1714 if (recipient == NULL)
1715 /* The function moan_smtp_batch() does not return. */
1716 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1717
1718 /* If the recipient address is unqualified, qualify it if permitted. Then
1719 add it to the list of recipients. */
1720
1721 if (recipient_domain == 0)
1722 {
1723 if (allow_unqualified_recipient)
1724 {
1725 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1726 recipient);
1727 recipient = rewrite_address_qualify(recipient, TRUE);
1728 }
1729 /* The function moan_smtp_batch() does not return. */
1730 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1731 "a domain");
1732 }
1733 receive_add_recipient(recipient, -1);
1734 break;
1735
1736
1737 /* The DATA command is legal only if it follows successful MAIL FROM
1738 and RCPT TO commands. This function is complete when a valid DATA
1739 command is encountered. */
1740
1741 case DATA_CMD:
1742 if (sender_address == NULL || recipients_count <= 0)
1743 {
1744 /* The function moan_smtp_batch() does not return. */
1745 if (sender_address == NULL)
1746 moan_smtp_batch(smtp_cmd_buffer,
1747 "503 MAIL FROM:<sender> command must precede DATA");
1748 else
1749 moan_smtp_batch(smtp_cmd_buffer,
1750 "503 RCPT TO:<recipient> must precede DATA");
1751 }
1752 else
1753 {
1754 done = 3; /* DATA successfully achieved */
1755 message_ended = END_NOTENDED; /* Indicate in middle of message */
1756 }
1757 break;
1758
1759
1760 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1761
1762 case VRFY_CMD:
1763 case EXPN_CMD:
1764 case HELP_CMD:
1765 case NOOP_CMD:
1766 case ETRN_CMD:
1767 bsmtp_transaction_linecount = receive_linecount;
1768 break;
1769
1770
1771 case EOF_CMD:
1772 case QUIT_CMD:
1773 done = 2;
1774 break;
1775
1776
1777 case BADARG_CMD:
1778 /* The function moan_smtp_batch() does not return. */
1779 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1780 break;
1781
1782
1783 case BADCHAR_CMD:
1784 /* The function moan_smtp_batch() does not return. */
1785 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1786 break;
1787
1788
1789 default:
1790 /* The function moan_smtp_batch() does not return. */
1791 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1792 break;
1793 }
1794 }
1795
1796 return done - 2; /* Convert yield values */
1797 }
1798
1799
1800
1801
1802 /*************************************************
1803 * Start an SMTP session *
1804 *************************************************/
1805
1806 /* This function is called at the start of an SMTP session. Thereafter,
1807 smtp_setup_msg() is called to initiate each separate message. This
1808 function does host-specific testing, and outputs the banner line.
1809
1810 Arguments: none
1811 Returns: FALSE if the session can not continue; something has
1812 gone wrong, or the connection to the host is blocked
1813 */
1814
1815 BOOL
1816 smtp_start_session(void)
1817 {
1818 int size = 256;
1819 int ptr, esclen;
1820 uschar *user_msg, *log_msg;
1821 uschar *code, *esc;
1822 uschar *p, *s, *ss;
1823
1824 smtp_connection_start = time(NULL);
1825 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1826 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1827 smtp_ch_index = 0;
1828
1829 /* Default values for certain variables */
1830
1831 helo_seen = esmtp = helo_accept_junk = FALSE;
1832 smtp_mailcmd_count = 0;
1833 count_nonmail = TRUE_UNSET;
1834 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1835 smtp_delay_mail = smtp_rlm_base;
1836 auth_advertised = FALSE;
1837 pipelining_advertised = FALSE;
1838 pipelining_enable = TRUE;
1839 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1840 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1841
1842 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1843
1844 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1845 authentication settings from -oMaa to remain in force. */
1846
1847 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1848 authenticated_by = NULL;
1849
1850 #ifdef SUPPORT_TLS
1851 tls_in.cipher = tls_in.peerdn = NULL;
1852 tls_in.ourcert = tls_in.peercert = NULL;
1853 tls_in.sni = NULL;
1854 tls_in.ocsp = OCSP_NOT_REQ;
1855 tls_advertised = FALSE;
1856 #endif
1857 #ifdef EXPERIMENTAL_DSN
1858 dsn_advertised = FALSE;
1859 #endif
1860
1861 /* Reset ACL connection variables */
1862
1863 acl_var_c = NULL;
1864
1865 /* Allow for trailing 0 in the command and data buffers. */
1866
1867 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1868 if (smtp_cmd_buffer == NULL)
1869 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1870 "malloc() failed for SMTP command buffer");
1871 smtp_cmd_buffer[0] = 0;
1872 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1873
1874 /* For batched input, the protocol setting can be overridden from the
1875 command line by a trusted caller. */
1876
1877 if (smtp_batched_input)
1878 {
1879 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1880 }
1881
1882 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1883 reset later if any of EHLO/AUTH/STARTTLS are received. */
1884
1885 else
1886 received_protocol =
1887 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1888
1889 /* Set up the buffer for inputting using direct read() calls, and arrange to
1890 call the local functions instead of the standard C ones. */
1891
1892 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1893 if (smtp_inbuffer == NULL)
1894 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1895 receive_getc = smtp_getc;
1896 receive_ungetc = smtp_ungetc;
1897 receive_feof = smtp_feof;
1898 receive_ferror = smtp_ferror;
1899 receive_smtp_buffered = smtp_buffered;
1900 smtp_inptr = smtp_inend = smtp_inbuffer;
1901 smtp_had_eof = smtp_had_error = 0;
1902
1903 /* Set up the message size limit; this may be host-specific */
1904
1905 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1906 if (expand_string_message != NULL)
1907 {
1908 if (thismessage_size_limit == -1)
1909 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1910 "%s", expand_string_message);
1911 else
1912 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1913 "%s", expand_string_message);
1914 smtp_closedown(US"Temporary local problem - please try later");
1915 return FALSE;
1916 }
1917
1918 /* When a message is input locally via the -bs or -bS options, sender_host_
1919 unknown is set unless -oMa was used to force an IP address, in which case it
1920 is checked like a real remote connection. When -bs is used from inetd, this
1921 flag is not set, causing the sending host to be checked. The code that deals
1922 with IP source routing (if configured) is never required for -bs or -bS and
1923 the flag sender_host_notsocket is used to suppress it.
1924
1925 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1926 reserve for certain hosts and/or networks. */
1927
1928 if (!sender_host_unknown)
1929 {
1930 int rc;
1931 BOOL reserved_host = FALSE;
1932
1933 /* Look up IP options (source routing info) on the socket if this is not an
1934 -oMa "host", and if any are found, log them and drop the connection.
1935
1936 Linux (and others now, see below) is different to everyone else, so there
1937 has to be some conditional compilation here. Versions of Linux before 2.1.15
1938 used a structure whose name was "options". Somebody finally realized that
1939 this name was silly, and it got changed to "ip_options". I use the
1940 newer name here, but there is a fudge in the script that sets up os.h
1941 to define a macro in older Linux systems.
1942
1943 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1944 glibc 2, which has chosen ip_opts for the structure name. This is now
1945 really a glibc thing rather than a Linux thing, so the condition name
1946 has been changed to reflect this. It is relevant also to GNU/Hurd.
1947
1948 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1949 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1950 a special macro defined in the os.h file.
1951
1952 Some DGUX versions on older hardware appear not to support IP options at
1953 all, so there is now a general macro which can be set to cut out this
1954 support altogether.
1955
1956 How to do this properly in IPv6 is not yet known. */
1957
1958 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1959
1960 #ifdef GLIBC_IP_OPTIONS
1961 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1962 #define OPTSTYLE 1
1963 #else
1964 #define OPTSTYLE 2
1965 #endif
1966 #elif defined DARWIN_IP_OPTIONS
1967 #define OPTSTYLE 2
1968 #else
1969 #define OPTSTYLE 3
1970 #endif
1971
1972 if (!host_checking && !sender_host_notsocket)
1973 {
1974 #if OPTSTYLE == 1
1975 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1976 struct ip_options *ipopt = store_get(optlen);
1977 #elif OPTSTYLE == 2
1978 struct ip_opts ipoptblock;
1979 struct ip_opts *ipopt = &ipoptblock;
1980 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1981 #else
1982 struct ipoption ipoptblock;
1983 struct ipoption *ipopt = &ipoptblock;
1984 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1985 #endif
1986
1987 /* Occasional genuine failures of getsockopt() have been seen - for
1988 example, "reset by peer". Therefore, just log and give up on this
1989 call, unless the error is ENOPROTOOPT. This error is given by systems
1990 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1991 of writing. So for that error, carry on - we just can't do an IP options
1992 check. */
1993
1994 DEBUG(D_receive) debug_printf("checking for IP options\n");
1995
1996 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1997 &optlen) < 0)
1998 {
1999 if (errno != ENOPROTOOPT)
2000 {
2001 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2002 host_and_ident(FALSE), strerror(errno));
2003 smtp_printf("451 SMTP service not available\r\n");
2004 return FALSE;
2005 }
2006 }
2007
2008 /* Deal with any IP options that are set. On the systems I have looked at,
2009 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2010 more logging data than will fit in big_buffer. Nevertheless, after somebody
2011 questioned this code, I've added in some paranoid checking. */
2012
2013 else if (optlen > 0)
2014 {
2015 uschar *p = big_buffer;
2016 uschar *pend = big_buffer + big_buffer_size;
2017 uschar *opt, *adptr;
2018 int optcount;
2019 struct in_addr addr;
2020
2021 #if OPTSTYLE == 1
2022 uschar *optstart = (uschar *)(ipopt->__data);
2023 #elif OPTSTYLE == 2
2024 uschar *optstart = (uschar *)(ipopt->ip_opts);
2025 #else
2026 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2027 #endif
2028
2029 DEBUG(D_receive) debug_printf("IP options exist\n");
2030
2031 Ustrcpy(p, "IP options on incoming call:");
2032 p += Ustrlen(p);
2033
2034 for (opt = optstart; opt != NULL &&
2035 opt < (uschar *)(ipopt) + optlen;)
2036 {
2037 switch (*opt)
2038 {
2039 case IPOPT_EOL:
2040 opt = NULL;
2041 break;
2042
2043 case IPOPT_NOP:
2044 opt++;
2045 break;
2046
2047 case IPOPT_SSRR:
2048 case IPOPT_LSRR:
2049 if (!string_format(p, pend-p, " %s [@%s",
2050 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2051 #if OPTSTYLE == 1
2052 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2053 #elif OPTSTYLE == 2
2054 inet_ntoa(ipopt->ip_dst)))
2055 #else
2056 inet_ntoa(ipopt->ipopt_dst)))
2057 #endif
2058 {
2059 opt = NULL;
2060 break;
2061 }
2062
2063 p += Ustrlen(p);
2064 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2065 adptr = opt + 3;
2066 while (optcount-- > 0)
2067 {
2068 memcpy(&addr, adptr, sizeof(addr));
2069 if (!string_format(p, pend - p - 1, "%s%s",
2070 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2071 {
2072 opt = NULL;
2073 break;
2074 }
2075 p += Ustrlen(p);
2076 adptr += sizeof(struct in_addr);
2077 }
2078 *p++ = ']';
2079 opt += opt[1];
2080 break;
2081
2082 default:
2083 {
2084 int i;
2085 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2086 Ustrcat(p, "[ ");
2087 p += 2;
2088 for (i = 0; i < opt[1]; i++)
2089 {
2090 sprintf(CS p, "%2.2x ", opt[i]);
2091 p += 3;
2092 }
2093 *p++ = ']';
2094 }
2095 opt += opt[1];
2096 break;
2097 }
2098 }
2099
2100 *p = 0;
2101 log_write(0, LOG_MAIN, "%s", big_buffer);
2102
2103 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2104
2105 log_write(0, LOG_MAIN|LOG_REJECT,
2106 "connection from %s refused (IP options)", host_and_ident(FALSE));
2107
2108 smtp_printf("554 SMTP service not available\r\n");
2109 return FALSE;
2110 }
2111
2112 /* Length of options = 0 => there are no options */
2113
2114 else DEBUG(D_receive) debug_printf("no IP options found\n");
2115 }
2116 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2117
2118 /* Set keep-alive in socket options. The option is on by default. This
2119 setting is an attempt to get rid of some hanging connections that stick in
2120 read() when the remote end (usually a dialup) goes away. */
2121
2122 if (smtp_accept_keepalive && !sender_host_notsocket)
2123 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2124
2125 /* If the current host matches host_lookup, set the name by doing a
2126 reverse lookup. On failure, sender_host_name will be NULL and
2127 host_lookup_failed will be TRUE. This may or may not be serious - optional
2128 checks later. */
2129
2130 if (verify_check_host(&host_lookup) == OK)
2131 {
2132 (void)host_name_lookup();
2133 host_build_sender_fullhost();
2134 }
2135
2136 /* Delay this until we have the full name, if it is looked up. */
2137
2138 set_process_info("handling incoming connection from %s",
2139 host_and_ident(FALSE));
2140
2141 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2142 smtps port for use with older style SSL MTAs. */
2143
2144 #ifdef SUPPORT_TLS
2145 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2146 return FALSE;
2147 #endif
2148
2149 /* Test for explicit connection rejection */
2150
2151 if (verify_check_host(&host_reject_connection) == OK)
2152 {
2153 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2154 "from %s (host_reject_connection)", host_and_ident(FALSE));
2155 smtp_printf("554 SMTP service not available\r\n");
2156 return FALSE;
2157 }
2158
2159 /* Test with TCP Wrappers if so configured. There is a problem in that
2160 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2161 such as disks dying. In these cases, it is desirable to reject with a 4xx
2162 error instead of a 5xx error. There isn't a "right" way to detect such
2163 problems. The following kludge is used: errno is zeroed before calling
2164 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2165 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2166 not exist). */
2167
2168 #ifdef USE_TCP_WRAPPERS
2169 errno = 0;
2170 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2171 if (tcp_wrappers_name == NULL)
2172 {
2173 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2174 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2175 expand_string_message);
2176 }
2177 if (!hosts_ctl(tcp_wrappers_name,
2178 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2179 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2180 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2181 {
2182 if (errno == 0 || errno == ENOENT)
2183 {
2184 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2185 log_write(L_connection_reject,
2186 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2187 "(tcp wrappers)", host_and_ident(FALSE));
2188 smtp_printf("554 SMTP service not available\r\n");
2189 }
2190 else
2191 {
2192 int save_errno = errno;
2193 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2194 "errno value %d\n", save_errno);
2195 log_write(L_connection_reject,
2196 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2197 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2198 smtp_printf("451 Temporary local problem - please try later\r\n");
2199 }
2200 return FALSE;
2201 }
2202 #endif
2203
2204 /* Check for reserved slots. The value of smtp_accept_count has already been
2205 incremented to include this process. */
2206
2207 if (smtp_accept_max > 0 &&
2208 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2209 {
2210 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2211 {
2212 log_write(L_connection_reject,
2213 LOG_MAIN, "temporarily refused connection from %s: not in "
2214 "reserve list: connected=%d max=%d reserve=%d%s",
2215 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2216 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2217 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2218 "please try again later\r\n", smtp_active_hostname);
2219 return FALSE;
2220 }
2221 reserved_host = TRUE;
2222 }
2223
2224 /* If a load level above which only messages from reserved hosts are
2225 accepted is set, check the load. For incoming calls via the daemon, the
2226 check is done in the superior process if there are no reserved hosts, to
2227 save a fork. In all cases, the load average will already be available
2228 in a global variable at this point. */
2229
2230 if (smtp_load_reserve >= 0 &&
2231 load_average > smtp_load_reserve &&
2232 !reserved_host &&
2233 verify_check_host(&smtp_reserve_hosts) != OK)
2234 {
2235 log_write(L_connection_reject,
2236 LOG_MAIN, "temporarily refused connection from %s: not in "
2237 "reserve list and load average = %.2f", host_and_ident(FALSE),
2238 (double)load_average/1000.0);
2239 smtp_printf("421 %s: Too much load; please try again later\r\n",
2240 smtp_active_hostname);
2241 return FALSE;
2242 }
2243
2244 /* Determine whether unqualified senders or recipients are permitted
2245 for this host. Unfortunately, we have to do this every time, in order to
2246 set the flags so that they can be inspected when considering qualifying
2247 addresses in the headers. For a site that permits no qualification, this
2248 won't take long, however. */
2249
2250 allow_unqualified_sender =
2251 verify_check_host(&sender_unqualified_hosts) == OK;
2252
2253 allow_unqualified_recipient =
2254 verify_check_host(&recipient_unqualified_hosts) == OK;
2255
2256 /* Determine whether HELO/EHLO is required for this host. The requirement
2257 can be hard or soft. */
2258
2259 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2260 if (!helo_required)
2261 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2262
2263 /* Determine whether this hosts is permitted to send syntactic junk
2264 after a HELO or EHLO command. */
2265
2266 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2267 }
2268
2269 /* For batch SMTP input we are now done. */
2270
2271 if (smtp_batched_input) return TRUE;
2272
2273 #ifdef EXPERIMENTAL_PROXY
2274 /* If valid Proxy Protocol source is connecting, set up session.
2275 * Failure will not allow any SMTP function other than QUIT. */
2276 proxy_session = FALSE;
2277 proxy_session_failed = FALSE;
2278 if (check_proxy_protocol_host())
2279 {
2280 if (setup_proxy_protocol_host() == FALSE)
2281 {
2282 proxy_session_failed = TRUE;
2283 DEBUG(D_receive)
2284 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2285 }
2286 else
2287 {
2288 sender_host_name = NULL;
2289 (void)host_name_lookup();
2290 host_build_sender_fullhost();
2291 }
2292 }
2293 #endif
2294
2295 /* Run the ACL if it exists */
2296
2297 user_msg = NULL;
2298 if (acl_smtp_connect != NULL)
2299 {
2300 int rc;
2301 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2302 &log_msg);
2303 if (rc != OK)
2304 {
2305 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2306 return FALSE;
2307 }
2308 }
2309
2310 /* Output the initial message for a two-way SMTP connection. It may contain
2311 newlines, which then cause a multi-line response to be given. */
2312
2313 code = US"220"; /* Default status code */
2314 esc = US""; /* Default extended status code */
2315 esclen = 0; /* Length of esc */
2316
2317 if (user_msg == NULL)
2318 {
2319 s = expand_string(smtp_banner);
2320 if (s == NULL)
2321 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2322 "failed: %s", smtp_banner, expand_string_message);
2323 }
2324 else
2325 {
2326 int codelen = 3;
2327 s = user_msg;
2328 smtp_message_code(&code, &codelen, &s, NULL);
2329 if (codelen > 4)
2330 {
2331 esc = code + 4;
2332 esclen = codelen - 4;
2333 }
2334 }
2335
2336 /* Remove any terminating newlines; might as well remove trailing space too */
2337
2338 p = s + Ustrlen(s);
2339 while (p > s && isspace(p[-1])) p--;
2340 *p = 0;
2341
2342 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2343 is all contained in a single IP packet. The original code wrote out the
2344 greeting using several calls to fprint/fputc, and on busy servers this could
2345 cause it to be split over more than one packet - which caused CC:Mail to fall
2346 over when it got the second part of the greeting after sending its first
2347 command. Sigh. To try to avoid this, build the complete greeting message
2348 first, and output it in one fell swoop. This gives a better chance of it
2349 ending up as a single packet. */
2350
2351 ss = store_get(size);
2352 ptr = 0;
2353
2354 p = s;
2355 do /* At least once, in case we have an empty string */
2356 {
2357 int len;
2358 uschar *linebreak = Ustrchr(p, '\n');
2359 ss = string_cat(ss, &size, &ptr, code, 3);
2360 if (linebreak == NULL)
2361 {
2362 len = Ustrlen(p);
2363 ss = string_cat(ss, &size, &ptr, US" ", 1);
2364 }
2365 else
2366 {
2367 len = linebreak - p;
2368 ss = string_cat(ss, &size, &ptr, US"-", 1);
2369 }
2370 ss = string_cat(ss, &size, &ptr, esc, esclen);
2371 ss = string_cat(ss, &size, &ptr, p, len);
2372 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
2373 p += len;
2374 if (linebreak != NULL) p++;
2375 }
2376 while (*p != 0);
2377
2378 ss[ptr] = 0; /* string_cat leaves room for this */
2379
2380 /* Before we write the banner, check that there is no input pending, unless
2381 this synchronisation check is disabled. */
2382
2383 if (!check_sync())
2384 {
2385 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2386 "synchronization error (input sent without waiting for greeting): "
2387 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2388 string_printing(smtp_inptr));
2389 smtp_printf("554 SMTP synchronization error\r\n");
2390 return FALSE;
2391 }
2392
2393 /* Now output the banner */
2394
2395 smtp_printf("%s", ss);
2396 return TRUE;
2397 }
2398
2399
2400
2401
2402
2403 /*************************************************
2404 * Handle SMTP syntax and protocol errors *
2405 *************************************************/
2406
2407 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2408 to do so. Then transmit the error response. The return value depends on the
2409 number of syntax and protocol errors in this SMTP session.
2410
2411 Arguments:
2412 type error type, given as a log flag bit
2413 code response code; <= 0 means don't send a response
2414 data data to reflect in the response (can be NULL)
2415 errmess the error message
2416
2417 Returns: -1 limit of syntax/protocol errors NOT exceeded
2418 +1 limit of syntax/protocol errors IS exceeded
2419
2420 These values fit in with the values of the "done" variable in the main
2421 processing loop in smtp_setup_msg(). */
2422
2423 static int
2424 synprot_error(int type, int code, uschar *data, uschar *errmess)
2425 {
2426 int yield = -1;
2427
2428 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2429 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2430 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2431
2432 if (++synprot_error_count > smtp_max_synprot_errors)
2433 {
2434 yield = 1;
2435 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2436 "syntax or protocol errors (last command was \"%s\")",
2437 host_and_ident(FALSE), smtp_cmd_buffer);
2438 }
2439
2440 if (code > 0)
2441 {
2442 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2443 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2444 if (yield == 1)
2445 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2446 }
2447
2448 return yield;
2449 }
2450
2451
2452
2453
2454 /*************************************************
2455 * Log incomplete transactions *
2456 *************************************************/
2457
2458 /* This function is called after a transaction has been aborted by RSET, QUIT,
2459 connection drops or other errors. It logs the envelope information received
2460 so far in order to preserve address verification attempts.
2461
2462 Argument: string to indicate what aborted the transaction
2463 Returns: nothing
2464 */
2465
2466 static void
2467 incomplete_transaction_log(uschar *what)
2468 {
2469 if (sender_address == NULL || /* No transaction in progress */
2470 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
2471 ) return;
2472
2473 /* Build list of recipients for logging */
2474
2475 if (recipients_count > 0)
2476 {
2477 int i;
2478 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2479 for (i = 0; i < recipients_count; i++)
2480 raw_recipients[i] = recipients_list[i].address;
2481 raw_recipients_count = recipients_count;
2482 }
2483
2484 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2485 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2486 }
2487
2488
2489
2490
2491 /*************************************************
2492 * Send SMTP response, possibly multiline *
2493 *************************************************/
2494
2495 /* There are, it seems, broken clients out there that cannot handle multiline
2496 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2497 output nothing for non-final calls, and only the first line for anything else.
2498
2499 Arguments:
2500 code SMTP code, may involve extended status codes
2501 codelen length of smtp code; if > 4 there's an ESC
2502 final FALSE if the last line isn't the final line
2503 msg message text, possibly containing newlines
2504
2505 Returns: nothing
2506 */
2507
2508 void
2509 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2510 {
2511 int esclen = 0;
2512 uschar *esc = US"";
2513
2514 if (!final && no_multiline_responses) return;
2515
2516 if (codelen > 4)
2517 {
2518 esc = code + 4;
2519 esclen = codelen - 4;
2520 }
2521
2522 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2523 have had the same. Note: this code is also present in smtp_printf(). It would
2524 be tidier to have it only in one place, but when it was added, it was easier to
2525 do it that way, so as not to have to mess with the code for the RCPT command,
2526 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2527
2528 if (rcpt_in_progress)
2529 {
2530 if (rcpt_smtp_response == NULL)
2531 rcpt_smtp_response = string_copy(msg);
2532 else if (rcpt_smtp_response_same &&
2533 Ustrcmp(rcpt_smtp_response, msg) != 0)
2534 rcpt_smtp_response_same = FALSE;
2535 rcpt_in_progress = FALSE;
2536 }
2537
2538 /* Not output the message, splitting it up into multiple lines if necessary. */
2539
2540 for (;;)
2541 {
2542 uschar *nl = Ustrchr(msg, '\n');
2543 if (nl == NULL)
2544 {
2545 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2546 return;
2547 }
2548 else if (nl[1] == 0 || no_multiline_responses)
2549 {
2550 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2551 (int)(nl - msg), msg);
2552 return;
2553 }
2554 else
2555 {
2556 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2557 msg = nl + 1;
2558 while (isspace(*msg)) msg++;
2559 }
2560 }
2561 }
2562
2563
2564
2565
2566 /*************************************************
2567 * Parse user SMTP message *
2568 *************************************************/
2569
2570 /* This function allows for user messages overriding the response code details
2571 by providing a suitable response code string at the start of the message
2572 user_msg. Check the message for starting with a response code and optionally an
2573 extended status code. If found, check that the first digit is valid, and if so,
2574 change the code pointer and length to use the replacement. An invalid code
2575 causes a panic log; in this case, if the log messages is the same as the user
2576 message, we must also adjust the value of the log message to show the code that
2577 is actually going to be used (the original one).
2578
2579 This function is global because it is called from receive.c as well as within
2580 this module.
2581
2582 Note that the code length returned includes the terminating whitespace
2583 character, which is always included in the regex match.
2584
2585 Arguments:
2586 code SMTP code, may involve extended status codes
2587 codelen length of smtp code; if > 4 there's an ESC
2588 msg message text
2589 log_msg optional log message, to be adjusted with the new SMTP code
2590
2591 Returns: nothing
2592 */
2593
2594 void
2595 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2596 {
2597 int n;
2598 int ovector[3];
2599
2600 if (msg == NULL || *msg == NULL) return;
2601
2602 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2603 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2604 if (n < 0) return;
2605
2606 if ((*msg)[0] != (*code)[0])
2607 {
2608 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2609 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2610 if (log_msg != NULL && *log_msg == *msg)
2611 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2612 }
2613 else
2614 {
2615 *code = *msg;
2616 *codelen = ovector[1]; /* Includes final space */
2617 }
2618 *msg += ovector[1]; /* Chop the code off the message */
2619 return;
2620 }
2621
2622
2623
2624
2625 /*************************************************
2626 * Handle an ACL failure *
2627 *************************************************/
2628
2629 /* This function is called when acl_check() fails. As well as calls from within
2630 this module, it is called from receive.c for an ACL after DATA. It sorts out
2631 logging the incident, and sets up the error response. A message containing
2632 newlines is turned into a multiline SMTP response, but for logging, only the
2633 first line is used.
2634
2635 There's a table of default permanent failure response codes to use in
2636 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2637 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2638 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2639 state, because there are broken clients that try VRFY before RCPT. A 5xx
2640 response should be given only when the address is positively known to be
2641 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2642 503.
2643
2644 From Exim 4.63, it is possible to override the response code details by
2645 providing a suitable response code string at the start of the message provided
2646 in user_msg. The code's first digit is checked for validity.
2647
2648 Arguments:
2649 where where the ACL was called from
2650 rc the failure code
2651 user_msg a message that can be included in an SMTP response
2652 log_msg a message for logging
2653
2654 Returns: 0 in most cases
2655 2 if the failure code was FAIL_DROP, in which case the
2656 SMTP connection should be dropped (this value fits with the
2657 "done" variable in smtp_setup_msg() below)
2658 */
2659
2660 int
2661 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2662 {
2663 BOOL drop = rc == FAIL_DROP;
2664 int codelen = 3;
2665 uschar *smtp_code;
2666 uschar *lognl;
2667 uschar *sender_info = US"";
2668 uschar *what =
2669 #ifdef WITH_CONTENT_SCAN
2670 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2671 #endif
2672 (where == ACL_WHERE_PREDATA)? US"DATA" :
2673 (where == ACL_WHERE_DATA)? US"after DATA" :
2674 #ifndef DISABLE_PRDR
2675 (where == ACL_WHERE_PRDR)? US"after DATA PRDR" :
2676 #endif
2677 (smtp_cmd_data == NULL)?
2678 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2679 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2680
2681 if (drop) rc = FAIL;
2682
2683 /* Set the default SMTP code, and allow a user message to change it. */
2684
2685 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2686 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2687
2688 /* We used to have sender_address here; however, there was a bug that was not
2689 updating sender_address after a rewrite during a verify. When this bug was
2690 fixed, sender_address at this point became the rewritten address. I'm not sure
2691 this is what should be logged, so I've changed to logging the unrewritten
2692 address to retain backward compatibility. */
2693
2694 #ifndef WITH_CONTENT_SCAN
2695 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2696 #else
2697 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2698 #endif
2699 {
2700 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2701 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2702 sender_host_authenticated ? US" A=" : US"",
2703 sender_host_authenticated ? sender_host_authenticated : US"",
2704 sender_host_authenticated && authenticated_id ? US":" : US"",
2705 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2706 );
2707 }
2708
2709 /* If there's been a sender verification failure with a specific message, and
2710 we have not sent a response about it yet, do so now, as a preliminary line for
2711 failures, but not defers. However, always log it for defer, and log it for fail
2712 unless the sender_verify_fail log selector has been turned off. */
2713
2714 if (sender_verified_failed != NULL &&
2715 !testflag(sender_verified_failed, af_sverify_told))
2716 {
2717 BOOL save_rcpt_in_progress = rcpt_in_progress;
2718 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2719
2720 setflag(sender_verified_failed, af_sverify_told);
2721
2722 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2723 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2724 host_and_ident(TRUE),
2725 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2726 sender_verified_failed->address,
2727 (sender_verified_failed->message == NULL)? US"" :
2728 string_sprintf(": %s", sender_verified_failed->message));
2729
2730 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2731 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2732 testflag(sender_verified_failed, af_verify_pmfail)?
2733 "Postmaster verification failed while checking <%s>\n%s\n"
2734 "Several RFCs state that you are required to have a postmaster\n"
2735 "mailbox for each mail domain. This host does not accept mail\n"
2736 "from domains whose servers reject the postmaster address."
2737 :
2738 testflag(sender_verified_failed, af_verify_nsfail)?
2739 "Callback setup failed while verifying <%s>\n%s\n"
2740 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2741 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2742 "RFC requirements, and stops you from receiving standard bounce\n"
2743 "messages. This host does not accept mail from domains whose servers\n"
2744 "refuse bounces."
2745 :
2746 "Verification failed for <%s>\n%s",
2747 sender_verified_failed->address,
2748 sender_verified_failed->user_message));
2749
2750 rcpt_in_progress = save_rcpt_in_progress;
2751 }
2752
2753 /* Sort out text for logging */
2754
2755 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2756 lognl = Ustrchr(log_msg, '\n');
2757 if (lognl != NULL) *lognl = 0;
2758
2759 /* Send permanent failure response to the command, but the code used isn't
2760 always a 5xx one - see comments at the start of this function. If the original
2761 rc was FAIL_DROP we drop the connection and yield 2. */
2762
2763 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2764 US"Administrative prohibition" : user_msg);
2765
2766 /* Send temporary failure response to the command. Don't give any details,
2767 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2768 verb, and for a header verify when smtp_return_error_details is set.
2769
2770 This conditional logic is all somewhat of a mess because of the odd
2771 interactions between temp_details and return_error_details. One day it should
2772 be re-implemented in a tidier fashion. */
2773
2774 else
2775 {
2776 if (acl_temp_details && user_msg != NULL)
2777 {
2778 if (smtp_return_error_details &&
2779 sender_verified_failed != NULL &&
2780 sender_verified_failed->message != NULL)
2781 {
2782 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2783 }
2784 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2785 }
2786 else
2787 smtp_respond(smtp_code, codelen, TRUE,
2788 US"Temporary local problem - please try later");
2789 }
2790
2791 /* Log the incident to the logs that are specified by log_reject_target
2792 (default main, reject). This can be empty to suppress logging of rejections. If
2793 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2794 is closing if required and return 2. */
2795
2796 if (log_reject_target != 0)
2797 {
2798 #ifdef SUPPORT_TLS
2799 uschar * s = s_tlslog(NULL, NULL, NULL);
2800 if (!s) s = US"";
2801 #else
2802 uschar * s = US"";
2803 #endif
2804 log_write(0, log_reject_target, "%s%s %s%srejected %s%s",
2805 host_and_ident(TRUE), s,
2806 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2807 }
2808
2809 if (!drop) return 0;
2810
2811 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2812 smtp_get_connection_info());
2813
2814 /* Run the not-quit ACL, but without any custom messages. This should not be a
2815 problem, because we get here only if some other ACL has issued "drop", and
2816 in that case, *its* custom messages will have been used above. */
2817
2818 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2819 return 2;
2820 }
2821
2822
2823
2824
2825 /*************************************************
2826 * Handle SMTP exit when QUIT is not given *
2827 *************************************************/
2828
2829 /* This function provides a logging/statistics hook for when an SMTP connection
2830 is dropped on the floor or the other end goes away. It's a global function
2831 because it's called from receive.c as well as this module. As well as running
2832 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2833 response, either with a custom message from the ACL, or using a default. There
2834 is one case, however, when no message is output - after "drop". In that case,
2835 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2836 passed to this function.
2837
2838 In case things go wrong while processing this function, causing an error that
2839 may re-enter this funtion, there is a recursion check.
2840
2841 Arguments:
2842 reason What $smtp_notquit_reason will be set to in the ACL;
2843 if NULL, the ACL is not run
2844 code The error code to return as part of the response
2845 defaultrespond The default message if there's no user_msg
2846
2847 Returns: Nothing
2848 */
2849
2850 void
2851 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2852 {
2853 int rc;
2854 uschar *user_msg = NULL;
2855 uschar *log_msg = NULL;
2856
2857 /* Check for recursive acll */
2858
2859 if (smtp_exit_function_called)
2860 {
2861 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2862 reason);
2863 return;
2864 }
2865 smtp_exit_function_called = TRUE;
2866
2867 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2868
2869 if (acl_smtp_notquit != NULL && reason != NULL)
2870 {
2871 smtp_notquit_reason = reason;
2872 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2873 &log_msg);
2874 if (rc == ERROR)
2875 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2876 log_msg);
2877 }
2878
2879 /* Write an SMTP response if we are expected to give one. As the default
2880 responses are all internal, they should always fit in the buffer, but code a
2881 warning, just in case. Note that string_vformat() still leaves a complete
2882 string, even if it is incomplete. */
2883
2884 if (code != NULL && defaultrespond != NULL)
2885 {
2886 if (user_msg == NULL)
2887 {
2888 uschar buffer[128];
2889 va_list ap;
2890 va_start(ap, defaultrespond);
2891 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2892 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2893 smtp_printf("%s %s\r\n", code, buffer);
2894 va_end(ap);
2895 }
2896 else
2897 smtp_respond(code, 3, TRUE, user_msg);
2898 mac_smtp_fflush();
2899 }
2900 }
2901
2902
2903
2904
2905 /*************************************************
2906 * Verify HELO argument *
2907 *************************************************/
2908
2909 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2910 matched. It is also called from ACL processing if verify = helo is used and
2911 verification was not previously tried (i.e. helo_try_verify_hosts was not
2912 matched). The result of its processing is to set helo_verified and
2913 helo_verify_failed. These variables should both be FALSE for this function to
2914 be called.
2915
2916 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2917 for IPv6 ::ffff: literals.
2918
2919 Argument: none
2920 Returns: TRUE if testing was completed;
2921 FALSE on a temporary failure
2922 */
2923
2924 BOOL
2925 smtp_verify_helo(void)
2926 {
2927 BOOL yield = TRUE;
2928
2929 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2930 sender_helo_name);
2931
2932 if (sender_helo_name == NULL)
2933 {
2934 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2935 }
2936
2937 /* Deal with the case of -bs without an IP address */
2938
2939 else if (sender_host_address == NULL)
2940 {
2941 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2942 helo_verified = TRUE;
2943 }
2944
2945 /* Deal with the more common case when there is a sending IP address */
2946
2947 else if (sender_helo_name[0] == '[')
2948 {
2949 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2950 Ustrlen(sender_host_address)) == 0;
2951
2952 #if HAVE_IPV6
2953 if (!helo_verified)
2954 {
2955 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2956 helo_verified = Ustrncmp(sender_helo_name + 1,
2957 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2958 }
2959 #endif
2960
2961 HDEBUG(D_receive)
2962 { if (helo_verified) debug_printf("matched host address\n"); }
2963 }
2964
2965 /* Do a reverse lookup if one hasn't already given a positive or negative
2966 response. If that fails, or the name doesn't match, try checking with a forward
2967 lookup. */
2968
2969 else
2970 {
2971 if (sender_host_name == NULL && !host_lookup_failed)
2972 yield = host_name_lookup() != DEFER;
2973
2974 /* If a host name is known, check it and all its aliases. */
2975
2976 if (sender_host_name != NULL)
2977 {
2978 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2979
2980 if (helo_verified)
2981 {
2982 HDEBUG(D_receive) debug_printf("matched host name\n");
2983 }
2984 else
2985 {
2986 uschar **aliases = sender_host_aliases;
2987 while (*aliases != NULL)
2988 {
2989 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2990 if (helo_verified) break;
2991 }
2992 HDEBUG(D_receive)
2993 {
2994 if (helo_verified)
2995 debug_printf("matched alias %s\n", *(--aliases));
2996 }
2997 }
2998 }
2999
3000 /* Final attempt: try a forward lookup of the helo name */
3001
3002 if (!helo_verified)
3003 {
3004 int rc;
3005 host_item h;
3006 h.name = sender_helo_name;
3007 h.address = NULL;
3008 h.mx = MX_NONE;
3009 h.next = NULL;
3010 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3011 sender_helo_name);
3012 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
3013 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3014 {
3015 host_item *hh = &h;
3016 while (hh != NULL)
3017 {
3018 if (Ustrcmp(hh->address, sender_host_address) == 0)
3019 {
3020 helo_verified = TRUE;
3021 HDEBUG(D_receive)
3022 debug_printf("IP address for %s matches calling address\n",
3023 sender_helo_name);
3024 break;
3025 }
3026 hh = hh->next;
3027 }
3028 }
3029 }
3030 }
3031
3032 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3033 return yield;
3034 }
3035
3036
3037
3038
3039 /*************************************************
3040 * Send user response message *
3041 *************************************************/
3042
3043 /* This function is passed a default response code and a user message. It calls
3044 smtp_message_code() to check and possibly modify the response code, and then
3045 calls smtp_respond() to transmit the response. I put this into a function
3046 just to avoid a lot of repetition.
3047
3048 Arguments:
3049 code the response code
3050 user_msg the user message
3051
3052 Returns: nothing
3053 */
3054
3055 static void
3056 smtp_user_msg(uschar *code, uschar *user_msg)
3057 {
3058 int len = 3;
3059 smtp_message_code(&code, &len, &user_msg, NULL);
3060 smtp_respond(code, len, TRUE, user_msg);
3061 }
3062
3063
3064
3065 /*************************************************
3066 * Initialize for SMTP incoming message *
3067 *************************************************/
3068
3069 /* This function conducts the initial dialogue at the start of an incoming SMTP
3070 message, and builds a list of recipients. However, if the incoming message
3071 is part of a batch (-bS option) a separate function is called since it would
3072 be messy having tests splattered about all over this function. This function
3073 therefore handles the case where interaction is occurring. The input and output
3074 files are set up in smtp_in and smtp_out.
3075
3076 The global recipients_list is set to point to a vector of recipient_item
3077 blocks, whose number is given by recipients_count. This is extended by the
3078 receive_add_recipient() function. The global variable sender_address is set to
3079 the sender's address. The yield is +1 if a message has been successfully
3080 started, 0 if a QUIT command was encountered or the connection was refused from
3081 the particular host, or -1 if the connection was lost.
3082
3083 Argument: none
3084
3085 Returns: > 0 message successfully started (reached DATA)
3086 = 0 QUIT read or end of file reached or call refused
3087 < 0 lost connection
3088 */
3089
3090 int
3091 smtp_setup_msg(void)
3092 {
3093 int done = 0;
3094 BOOL toomany = FALSE;
3095 BOOL discarded = FALSE;
3096 BOOL last_was_rej_mail = FALSE;
3097 BOOL last_was_rcpt = FALSE;
3098 void *reset_point = store_get(0);
3099
3100 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3101
3102 /* Reset for start of new message. We allow one RSET not to be counted as a
3103 nonmail command, for those MTAs that insist on sending it between every
3104 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3105 TLS between messages (an Exim client may do this if it has messages queued up
3106 for the host). Note: we do NOT reset AUTH at this point. */
3107
3108 smtp_reset(reset_point);
3109 message_ended = END_NOTSTARTED;
3110
3111 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3112 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3113 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3114 #ifdef SUPPORT_TLS
3115 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3116 #endif
3117
3118 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3119
3120 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3121
3122 /* Batched SMTP is handled in a different function. */
3123
3124 if (smtp_batched_input) return smtp_setup_batch_msg();
3125
3126 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3127 value. The values are 2 larger than the required yield of the function. */
3128
3129 while (done <= 0)
3130 {
3131 uschar **argv;
3132 uschar *etrn_command;
3133 uschar *etrn_serialize_key;
3134 uschar *errmess;
3135 uschar *log_msg, *smtp_code;
3136 uschar *user_msg = NULL;
3137 uschar *recipient = NULL;
3138 uschar *hello = NULL;
3139 uschar *set_id = NULL;
3140 uschar *s, *ss;
3141 BOOL was_rej_mail = FALSE;
3142 BOOL was_rcpt = FALSE;
3143 void (*oldsignal)(int);
3144 pid_t pid;
3145 int start, end, sender_domain, recipient_domain;
3146 int ptr, size, rc;
3147 int c, i;
3148 auth_instance *au;
3149 #ifdef EXPERIMENTAL_DSN
3150 uschar *orcpt = NULL;
3151 int flags;
3152 #endif
3153
3154 switch(smtp_read_command(TRUE))
3155 {
3156 /* The AUTH command is not permitted to occur inside a transaction, and may
3157 occur successfully only once per connection. Actually, that isn't quite
3158 true. When TLS is started, all previous information about a connection must
3159 be discarded, so a new AUTH is permitted at that time.
3160
3161 AUTH may only be used when it has been advertised. However, it seems that
3162 there are clients that send AUTH when it hasn't been advertised, some of
3163 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3164 So there's a get-out that allows this to happen.
3165
3166 AUTH is initially labelled as a "nonmail command" so that one occurrence
3167 doesn't get counted. We change the label here so that multiple failing
3168 AUTHS will eventually hit the nonmail threshold. */
3169
3170 case AUTH_CMD:
3171 HAD(SCH_AUTH);
3172 authentication_failed = TRUE;
3173 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3174
3175 if (!auth_advertised && !allow_auth_unadvertised)
3176 {
3177 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3178 US"AUTH command used when not advertised");
3179 break;
3180 }
3181 if (sender_host_authenticated != NULL)
3182 {
3183 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3184 US"already authenticated");
3185 break;
3186 }
3187 if (sender_address != NULL)
3188 {
3189 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3190 US"not permitted in mail transaction");
3191 break;
3192 }
3193
3194 /* Check the ACL */
3195
3196 if (acl_smtp_auth != NULL)
3197 {
3198 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
3199 if (rc != OK)
3200 {
3201 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3202 break;
3203 }
3204 }
3205
3206 /* Find the name of the requested authentication mechanism. */
3207
3208 s = smtp_cmd_data;
3209 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3210 {
3211 if (!isalnum(c) && c != '-' && c != '_')
3212 {
3213 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3214 US"invalid character in authentication mechanism name");
3215 goto COMMAND_LOOP;
3216 }
3217 smtp_cmd_data++;
3218 }
3219
3220 /* If not at the end of the line, we must be at white space. Terminate the
3221 name and move the pointer on to any data that may be present. */
3222
3223 if (*smtp_cmd_data != 0)
3224 {
3225 *smtp_cmd_data++ = 0;
3226 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3227 }
3228
3229 /* Search for an authentication mechanism which is configured for use
3230 as a server and which has been advertised (unless, sigh, allow_auth_
3231 unadvertised is set). */
3232
3233 for (au = auths; au != NULL; au = au->next)
3234 {
3235 if (strcmpic(s, au->public_name) == 0 && au->server &&
3236 (au->advertised || allow_auth_unadvertised)) break;
3237 }
3238
3239 if (au == NULL)
3240 {
3241 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3242 string_sprintf("%s authentication mechanism not supported", s));
3243 break;
3244 }
3245
3246 /* Run the checking code, passing the remainder of the command line as
3247 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3248 it as the only set numerical variable. The authenticator may set $auth<n>
3249 and also set other numeric variables. The $auth<n> variables are preferred
3250 nowadays; the numerical variables remain for backwards compatibility.
3251
3252 Afterwards, have a go at expanding the set_id string, even if
3253 authentication failed - for bad passwords it can be useful to log the
3254 userid. On success, require set_id to expand and exist, and put it in
3255 authenticated_id. Save this in permanent store, as the working store gets
3256 reset at HELO, RSET, etc. */
3257
3258 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3259 expand_nmax = 0;
3260 expand_nlength[0] = 0; /* $0 contains nothing */
3261
3262 c = (au->info->servercode)(au, smtp_cmd_data);
3263 if (au->set_id != NULL) set_id = expand_string(au->set_id);
3264 expand_nmax = -1; /* Reset numeric variables */
3265 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3266
3267 /* The value of authenticated_id is stored in the spool file and printed in
3268 log lines. It must not contain binary zeros or newline characters. In
3269 normal use, it never will, but when playing around or testing, this error
3270 can (did) happen. To guard against this, ensure that the id contains only
3271 printing characters. */
3272
3273 if (set_id != NULL) set_id = string_printing(set_id);
3274
3275 /* For the non-OK cases, set up additional logging data if set_id
3276 is not empty. */
3277
3278 if (c != OK)
3279 {
3280 if (set_id != NULL && *set_id != 0)
3281 set_id = string_sprintf(" (set_id=%s)", set_id);
3282 else set_id = US"";
3283 }
3284
3285 /* Switch on the result */
3286
3287 switch(c)
3288 {
3289 case OK:
3290 if (au->set_id == NULL || set_id != NULL) /* Complete success */
3291 {
3292 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
3293 sender_host_authenticated = au->name;
3294 authentication_failed = FALSE;
3295 authenticated_fail_id = NULL; /* Impossible to already be set? */
3296 received_protocol =
3297 protocols[pextend + pauthed + ((tls_in.active >= 0)? pcrpted:0)] +
3298 ((sender_host_address != NULL)? pnlocal : 0);
3299 s = ss = US"235 Authentication succeeded";
3300 authenticated_by = au;
3301 break;
3302 }
3303
3304 /* Authentication succeeded, but we failed to expand the set_id string.
3305 Treat this as a temporary error. */
3306
3307 auth_defer_msg = expand_string_message;
3308 /* Fall through */
3309
3310 case DEFER:
3311 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3312 s = string_sprintf("435 Unable to authenticate at present%s",
3313 auth_defer_user_msg);
3314 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3315 set_id, auth_defer_msg);
3316 break;
3317
3318 case BAD64:
3319 s = ss = US"501 Invalid base64 data";
3320 break;
3321
3322 case CANCELLED:
3323 s = ss = US"501 Authentication cancelled";
3324 break;
3325
3326 case UNEXPECTED:
3327 s = ss = US"553 Initial data not expected";
3328 break;
3329
3330 case FAIL:
3331 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3332 s = US"535 Incorrect authentication data";
3333 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3334 break;
3335
3336 default:
3337 if (set_id != NULL) authenticated_fail_id = string_copy_malloc(set_id);
3338 s = US"435 Internal error";
3339 ss = string_sprintf("435 Internal error%s: return %d from authentication "
3340 "check", set_id, c);
3341 break;
3342 }
3343
3344 smtp_printf("%s\r\n", s);
3345 if (c != OK)
3346 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3347 au->name, host_and_ident(FALSE), ss);
3348
3349 break; /* AUTH_CMD */
3350
3351 /* The HELO/EHLO commands are permitted to appear in the middle of a
3352 session as well as at the beginning. They have the effect of a reset in
3353 addition to their other functions. Their absence at the start cannot be
3354 taken to be an error.
3355
3356 RFC 2821 says:
3357
3358 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3359 or 502 failure replies MUST be returned as appropriate. The SMTP
3360 server MUST stay in the same state after transmitting these replies
3361 that it was in before the EHLO was received.
3362
3363 Therefore, we do not do the reset until after checking the command for
3364 acceptability. This change was made for Exim release 4.11. Previously
3365 it did the reset first. */
3366
3367 case HELO_CMD:
3368 HAD(SCH_HELO);
3369 hello = US"HELO";
3370 esmtp = FALSE;
3371 goto HELO_EHLO;
3372
3373 case EHLO_CMD:
3374 HAD(SCH_EHLO);
3375 hello = US"EHLO";
3376 esmtp = TRUE;
3377
3378 HELO_EHLO: /* Common code for HELO and EHLO */
3379 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3380 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3381
3382 /* Reject the HELO if its argument was invalid or non-existent. A
3383 successful check causes the argument to be saved in malloc store. */
3384
3385 if (!check_helo(smtp_cmd_data))
3386 {
3387 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3388
3389 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3390 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3391 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3392 string_printing(smtp_cmd_argument));
3393
3394 if (++synprot_error_count > smtp_max_synprot_errors)
3395 {
3396 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3397 "syntax or protocol errors (last command was \"%s\")",
3398 host_and_ident(FALSE), smtp_cmd_buffer);
3399 done = 1;
3400 }
3401
3402 break;
3403 }
3404
3405 /* If sender_host_unknown is true, we have got here via the -bs interface,
3406 not called from inetd. Otherwise, we are running an IP connection and the
3407 host address will be set. If the helo name is the primary name of this
3408 host and we haven't done a reverse lookup, force one now. If helo_required
3409 is set, ensure that the HELO name matches the actual host. If helo_verify
3410 is set, do the same check, but softly. */
3411
3412 if (!sender_host_unknown)
3413 {
3414 BOOL old_helo_verified = helo_verified;
3415 uschar *p = smtp_cmd_data;
3416
3417 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3418 *p = 0;
3419
3420 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3421 because otherwise the log can be confusing. */
3422
3423 if (sender_host_name == NULL &&
3424 (deliver_domain = sender_helo_name, /* set $domain */
3425 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
3426 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3427 (void)host_name_lookup();
3428
3429 /* Rebuild the fullhost info to include the HELO name (and the real name
3430 if it was looked up.) */
3431
3432 host_build_sender_fullhost(); /* Rebuild */
3433 set_process_info("handling%s incoming connection from %s",
3434 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3435
3436 /* Verify if configured. This doesn't give much security, but it does
3437 make some people happy to be able to do it. If helo_required is set,
3438 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3439 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3440 now obsolescent, since the verification can now be requested selectively
3441 at ACL time. */
3442
3443 helo_verified = helo_verify_failed = FALSE;
3444 if (helo_required || helo_verify)
3445 {
3446 BOOL tempfail = !smtp_verify_helo();
3447 if (!helo_verified)
3448 {
3449 if (helo_required)
3450 {
3451 smtp_printf("%d %s argument does not match calling host\r\n",
3452 tempfail? 451 : 550, hello);
3453 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3454 tempfail? "temporarily " : "",
3455 hello, sender_helo_name, host_and_ident(FALSE));
3456 helo_verified = old_helo_verified;
3457 break; /* End of HELO/EHLO processing */
3458 }
3459 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3460 "helo_try_verify_hosts\n", hello);
3461 }
3462 }
3463 }
3464
3465 #ifdef EXPERIMENTAL_SPF
3466 /* set up SPF context */
3467 spf_init(sender_helo_name, sender_host_address);
3468 #endif
3469
3470 /* Apply an ACL check if one is defined; afterwards, recheck
3471 synchronization in case the client started sending in a delay. */
3472
3473 if (acl_smtp_helo != NULL)
3474 {
3475 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
3476 if (rc != OK)
3477 {
3478 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3479 sender_helo_name = NULL;
3480 host_build_sender_fullhost(); /* Rebuild */
3481 break;
3482 }
3483 else if (!check_sync()) goto SYNC_FAILURE;
3484 }
3485
3486 /* Generate an OK reply. The default string includes the ident if present,
3487 and also the IP address if present. Reflecting back the ident is intended
3488 as a deterrent to mail forgers. For maximum efficiency, and also because
3489 some broken systems expect each response to be in a single packet, arrange
3490 that the entire reply is sent in one write(). */
3491
3492 auth_advertised = FALSE;
3493 pipelining_advertised = FALSE;
3494 #ifdef SUPPORT_TLS
3495 tls_advertised = FALSE;
3496 #endif
3497 #ifdef EXPERIMENTAL_DSN
3498 dsn_advertised = FALSE;
3499 #endif
3500
3501 smtp_code = US"250 "; /* Default response code plus space*/
3502 if (user_msg == NULL)
3503 {
3504 s = string_sprintf("%.3s %s Hello %s%s%s",
3505 smtp_code,