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