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