Correct error in previous patch.
[exim.git] / src / src / smtp_in.c
CommitLineData
d1d5595c 1/* $Cambridge: exim/src/src/smtp_in.c,v 1.46 2006/10/23 10:55:10 ph10 Exp $ */
059ec3d9
PH
2
3/*************************************************
4* Exim - an Internet mail transport agent *
5*************************************************/
6
d7d7b7b9 7/* Copyright (c) University of Cambridge 1995 - 2006 */
059ec3d9
PH
8/* See the file NOTICE for conditions of use and distribution. */
9
10/* Functions for handling an incoming SMTP call. */
11
12
13#include "exim.h"
14
15
16/* Initialize for TCP wrappers if so configured. It appears that the macro
17HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18including that header, and restore its value afterwards. */
19
20#ifdef USE_TCP_WRAPPERS
21
22 #if HAVE_IPV6
23 #define EXIM_HAVE_IPV6
24 #endif
25 #undef HAVE_IPV6
26 #include <tcpd.h>
27 #undef HAVE_IPV6
28 #ifdef EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
30 #endif
31
32int allow_severity = LOG_INFO;
33int deny_severity = LOG_NOTICE;
34#endif
35
36
8d67ada3
PH
37/* Size of buffer for reading SMTP commands. We used to use 512, as defined
38by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39commands that accept arguments, and this in particular applies to AUTH, where
40the data can be quite long. */
059ec3d9 41
3ee512ff 42#define smtp_cmd_buffer_size 2048
059ec3d9
PH
43
44/* Size of buffer for reading SMTP incoming packets */
45
46#define in_buffer_size 8192
47
48/* Structure for SMTP command list */
49
50typedef struct {
51 char *name;
52 int len;
53 short int cmd;
54 short int has_arg;
55 short int is_mail_cmd;
56} smtp_cmd_list;
57
58/* Codes for identifying commands. We order them so that those that come first
59are those for which synchronization is always required. Checking this can help
60block some spam. */
61
62enum {
63 /* These commands are required to be synchronized, i.e. to be the last in a
64 block of commands when pipelining. */
65
66 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
67 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
68 ETRN_CMD, /* This by analogy with TURN from the RFC */
69 STARTTLS_CMD, /* Required by the STARTTLS RFC */
70
71 /* This is a dummy to identify the non-sync commands when pipelining */
72
73 NON_SYNC_CMD_PIPELINING,
74
75 /* These commands need not be synchronized when pipelining */
76
77 MAIL_CMD, RCPT_CMD, RSET_CMD,
78
79 /* This is a dummy to identify the non-sync commands when not pipelining */
80
81 NON_SYNC_CMD_NON_PIPELINING,
82
83 /* I have been unable to find a statement about the use of pipelining
84 with AUTH, so to be on the safe side it is here, though I kind of feel
85 it should be up there with the synchronized commands. */
86
87 AUTH_CMD,
88
89 /* I'm not sure about these, but I don't think they matter. */
90
91 QUIT_CMD, HELP_CMD,
92
93 /* These are specials that don't correspond to actual commands */
94
95 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
96 TOO_MANY_NONMAIL_CMD };
97
98
99
100/*************************************************
101* Local static variables *
102*************************************************/
103
104static auth_instance *authenticated_by;
105static BOOL auth_advertised;
106#ifdef SUPPORT_TLS
107static BOOL tls_advertised;
108#endif
109static BOOL esmtp;
110static BOOL helo_required = FALSE;
111static BOOL helo_verify = FALSE;
112static BOOL helo_seen;
113static BOOL helo_accept_junk;
114static BOOL count_nonmail;
115static BOOL pipelining_advertised;
116static int nonmail_command_count;
117static int synprot_error_count;
118static int unknown_command_count;
119static int sync_cmd_limit;
120static int smtp_write_error = 0;
121
059ec3d9
PH
122/* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
123final fields of all except AUTH are forced TRUE at the start of a new message
124setup, to allow one of each between messages that is not counted as a nonmail
125command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
126allow a new EHLO after starting up TLS.
127
128AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
129counted. However, the flag is changed when AUTH is received, so that multiple
130failing AUTHs will eventually hit the limit. After a successful AUTH, another
131AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
132forced TRUE, to allow for the re-authentication that can happen at that point.
133
134QUIT is also "falsely" labelled as a mail command so that it doesn't up the
135count of non-mail commands and possibly provoke an error. */
136
137static smtp_cmd_list cmd_list[] = {
138 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
139 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
140 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
141 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
142 #ifdef SUPPORT_TLS
143 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
144 #endif
145
146/* If you change anything above here, also fix the definitions below. */
147
148 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
149 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
150 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
151 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
152 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
153 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
154 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
155 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
156 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
157};
158
159static smtp_cmd_list *cmd_list_end =
160 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
161
162#define CMD_LIST_RSET 0
163#define CMD_LIST_HELO 1
164#define CMD_LIST_EHLO 2
165#define CMD_LIST_AUTH 3
166#define CMD_LIST_STARTTLS 4
167
168static uschar *protocols[] = {
981756db
PH
169 US"local-smtp", /* HELO */
170 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
171 US"local-esmtp", /* EHLO */
172 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
173 US"local-esmtpa", /* EHLO->AUTH */
174 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
059ec3d9
PH
175 };
176
177#define pnormal 0
981756db
PH
178#define pextend 2
179#define pcrpted 1 /* added to pextend or pnormal */
180#define pauthed 2 /* added to pextend */
059ec3d9
PH
181#define pnlocal 6 /* offset to remove "local" */
182
183/* When reading SMTP from a remote host, we have to use our own versions of the
184C input-reading functions, in order to be able to flush the SMTP output only
185when about to read more data from the socket. This is the only way to get
186optimal performance when the client is using pipelining. Flushing for every
187command causes a separate packet and reply packet each time; saving all the
188responses up (when pipelining) combines them into one packet and one response.
189
190For simplicity, these functions are used for *all* SMTP input, not only when
191receiving over a socket. However, after setting up a secure socket (SSL), input
192is read via the OpenSSL library, and another set of functions is used instead
193(see tls.c).
194
195These functions are set in the receive_getc etc. variables and called with the
196same interface as the C functions. However, since there can only ever be
197one incoming SMTP call, we just use a single buffer and flags. There is no need
198to implement a complicated private FILE-like structure.*/
199
200static uschar *smtp_inbuffer;
201static uschar *smtp_inptr;
202static uschar *smtp_inend;
203static int smtp_had_eof;
204static int smtp_had_error;
205
206
207/*************************************************
208* SMTP version of getc() *
209*************************************************/
210
211/* This gets the next byte from the SMTP input buffer. If the buffer is empty,
212it flushes the output, and refills the buffer, with a timeout. The signal
213handler is set appropriately by the calling function. This function is not used
214after a connection has negotated itself into an TLS/SSL state.
215
216Arguments: none
217Returns: the next character or EOF
218*/
219
220int
221smtp_getc(void)
222{
223if (smtp_inptr >= smtp_inend)
224 {
225 int rc, save_errno;
226 fflush(smtp_out);
227 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
228 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
229 save_errno = errno;
230 alarm(0);
231 if (rc <= 0)
232 {
233 /* Must put the error text in fixed store, because this might be during
234 header reading, where it releases unused store above the header. */
235 if (rc < 0)
236 {
237 smtp_had_error = save_errno;
238 smtp_read_error = string_copy_malloc(
239 string_sprintf(" (error: %s)", strerror(save_errno)));
240 }
241 else smtp_had_eof = 1;
242 return EOF;
243 }
244 smtp_inend = smtp_inbuffer + rc;
245 smtp_inptr = smtp_inbuffer;
246 }
247return *smtp_inptr++;
248}
249
250
251
252/*************************************************
253* SMTP version of ungetc() *
254*************************************************/
255
256/* Puts a character back in the input buffer. Only ever
257called once.
258
259Arguments:
260 ch the character
261
262Returns: the character
263*/
264
265int
266smtp_ungetc(int ch)
267{
268*(--smtp_inptr) = ch;
269return ch;
270}
271
272
273
274
275/*************************************************
276* SMTP version of feof() *
277*************************************************/
278
279/* Tests for a previous EOF
280
281Arguments: none
282Returns: non-zero if the eof flag is set
283*/
284
285int
286smtp_feof(void)
287{
288return smtp_had_eof;
289}
290
291
292
293
294/*************************************************
295* SMTP version of ferror() *
296*************************************************/
297
298/* Tests for a previous read error, and returns with errno
299restored to what it was when the error was detected.
300
301Arguments: none
302Returns: non-zero if the error flag is set
303*/
304
305int
306smtp_ferror(void)
307{
308errno = smtp_had_error;
309return smtp_had_error;
310}
311
312
313
314
315/*************************************************
316* Write formatted string to SMTP channel *
317*************************************************/
318
319/* This is a separate function so that we don't have to repeat everything for
320TLS support or debugging. It is global so that the daemon and the
321authentication functions can use it. It does not return any error indication,
322because major problems such as dropped connections won't show up till an output
323flush for non-TLS connections. The smtp_fflush() function is available for
324checking that: for convenience, TLS output errors are remembered here so that
325they are also picked up later by smtp_fflush().
326
327Arguments:
328 format format string
329 ... optional arguments
330
331Returns: nothing
332*/
333
334void
335smtp_printf(char *format, ...)
336{
337va_list ap;
338
339DEBUG(D_receive)
340 {
898d150f 341 uschar *cr, *end;
059ec3d9
PH
342 va_start(ap, format);
343 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
898d150f
PH
344 va_end(ap);
345 end = big_buffer + Ustrlen(big_buffer);
346 while ((cr = Ustrchr(big_buffer, '\r')) != NULL) /* lose CRs */
347 memmove(cr, cr + 1, (end--) - cr);
059ec3d9
PH
348 debug_printf("SMTP>> %s", big_buffer);
349 }
350
351va_start(ap, format);
352
353/* If in a TLS session we have to format the string, and then write it using a
354TLS function. */
355
356#ifdef SUPPORT_TLS
357if (tls_active >= 0)
358 {
359 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
360 {
361 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
362 smtp_closedown(US"Unexpected error");
363 exim_exit(EXIT_FAILURE);
364 }
365 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
366 }
367else
368#endif
369
370/* Otherwise, just use the standard library function. */
371
372if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
373va_end(ap);
374}
375
376
377
378/*************************************************
379* Flush SMTP out and check for error *
380*************************************************/
381
382/* This function isn't currently used within Exim (it detects errors when it
383tries to read the next SMTP input), but is available for use in local_scan().
384For non-TLS connections, it flushes the output and checks for errors. For
385TLS-connections, it checks for a previously-detected TLS write error.
386
387Arguments: none
388Returns: 0 for no error; -1 after an error
389*/
390
391int
392smtp_fflush(void)
393{
394if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
395return smtp_write_error;
396}
397
398
399
400/*************************************************
401* SMTP command read timeout *
402*************************************************/
403
404/* Signal handler for timing out incoming SMTP commands. This attempts to
405finish off tidily.
406
407Argument: signal number (SIGALRM)
408Returns: nothing
409*/
410
411static void
412command_timeout_handler(int sig)
413{
414sig = sig; /* Keep picky compilers happy */
415log_write(L_lost_incoming_connection,
416 LOG_MAIN, "SMTP command timeout on%s connection from %s",
417 (tls_active >= 0)? " TLS" : "",
418 host_and_ident(FALSE));
419if (smtp_batched_input)
420 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
421smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
422 smtp_active_hostname);
423mac_smtp_fflush();
424exim_exit(EXIT_FAILURE);
425}
426
427
428
429/*************************************************
430* SIGTERM received *
431*************************************************/
432
433/* Signal handler for handling SIGTERM. Again, try to finish tidily.
434
435Argument: signal number (SIGTERM)
436Returns: nothing
437*/
438
439static void
440command_sigterm_handler(int sig)
441{
442sig = sig; /* Keep picky compilers happy */
443log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
444if (smtp_batched_input)
445 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
446smtp_printf("421 %s: Service not available - closing connection\r\n",
447 smtp_active_hostname);
448exim_exit(EXIT_FAILURE);
449}
450
451
452
453/*************************************************
454* Read one command line *
455*************************************************/
456
457/* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
458There are sites that don't do this, and in any case internal SMTP probably
459should check only for LF. Consequently, we check here for LF only. The line
460ends up with [CR]LF removed from its end. If we get an overlong line, treat as
3ee512ff
PH
461an unknown command. The command is read into the global smtp_cmd_buffer so that
462it is available via $smtp_command.
059ec3d9
PH
463
464The character reading routine sets up a timeout for each block actually read
465from the input (which may contain more than one command). We set up a special
466signal handler that closes down the session on a timeout. Control does not
467return when it runs.
468
469Arguments:
470 check_sync if TRUE, check synchronization rules if global option is TRUE
471
472Returns: a code identifying the command (enumerated above)
473*/
474
475static int
476smtp_read_command(BOOL check_sync)
477{
478int c;
479int ptr = 0;
480smtp_cmd_list *p;
481BOOL hadnull = FALSE;
482
483os_non_restarting_signal(SIGALRM, command_timeout_handler);
484
485while ((c = (receive_getc)()) != '\n' && c != EOF)
486 {
3ee512ff 487 if (ptr >= smtp_cmd_buffer_size)
059ec3d9
PH
488 {
489 os_non_restarting_signal(SIGALRM, sigalrm_handler);
490 return OTHER_CMD;
491 }
492 if (c == 0)
493 {
494 hadnull = TRUE;
495 c = '?';
496 }
3ee512ff 497 smtp_cmd_buffer[ptr++] = c;
059ec3d9
PH
498 }
499
500receive_linecount++; /* For BSMTP errors */
501os_non_restarting_signal(SIGALRM, sigalrm_handler);
502
503/* If hit end of file, return pseudo EOF command. Whether we have a
504part-line already read doesn't matter, since this is an error state. */
505
506if (c == EOF) return EOF_CMD;
507
508/* Remove any CR and white space at the end of the line, and terminate the
509string. */
510
3ee512ff
PH
511while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
512smtp_cmd_buffer[ptr] = 0;
059ec3d9 513
3ee512ff 514DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
059ec3d9
PH
515
516/* NULLs are not allowed in SMTP commands */
517
518if (hadnull) return BADCHAR_CMD;
519
520/* Scan command list and return identity, having set the data pointer
521to the start of the actual data characters. Check for SMTP synchronization
522if required. */
523
524for (p = cmd_list; p < cmd_list_end; p++)
525 {
084efe8d
PH
526 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
527 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
528 smtp_cmd_buffer[p->len] == 0 ||
529 smtp_cmd_buffer[p->len] == ' '))
059ec3d9
PH
530 {
531 if (smtp_inptr < smtp_inend && /* Outstanding input */
532 p->cmd < sync_cmd_limit && /* Command should sync */
533 check_sync && /* Local flag set */
534 smtp_enforce_sync && /* Global flag set */
535 sender_host_address != NULL && /* Not local input */
536 !sender_host_notsocket) /* Really is a socket */
537 return BADSYN_CMD;
538
539 /* Point after the command, but don't skip over leading spaces till after
540 the following test, so that if it fails, the command name can easily be
541 logged. */
542
3ee512ff 543 smtp_cmd_argument = smtp_cmd_buffer + p->len;
059ec3d9
PH
544
545 /* Count non-mail commands from those hosts that are controlled in this
546 way. The default is all hosts. We don't waste effort checking the list
547 until we get a non-mail command, but then cache the result to save checking
548 again. If there's a DEFER while checking the host, assume it's in the list.
549
550 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
551 start of each incoming message by fiddling with the value in the table. */
552
553 if (!p->is_mail_cmd)
554 {
555 if (count_nonmail == TRUE_UNSET) count_nonmail =
556 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
557 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
558 return TOO_MANY_NONMAIL_CMD;
559 }
560
64ffc24f
PH
561 /* Get the data pointer over leading spaces and return; if there is data
562 for a command that does not expect it, give the error centrally here. */
059ec3d9 563
3ee512ff
PH
564 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
565 return (p->has_arg || *smtp_cmd_argument == 0)? p->cmd : BADARG_CMD;
059ec3d9
PH
566 }
567 }
568
569/* Enforce synchronization for unknown commands */
570
571if (smtp_inptr < smtp_inend && /* Outstanding input */
572 check_sync && /* Local flag set */
573 smtp_enforce_sync && /* Global flag set */
574 sender_host_address != NULL && /* Not local input */
575 !sender_host_notsocket) /* Really is a socket */
576 return BADSYN_CMD;
577
578return OTHER_CMD;
579}
580
581
582
583/*************************************************
584* Forced closedown of call *
585*************************************************/
586
587/* This function is called from log.c when Exim is dying because of a serious
588disaster, and also from some other places. If an incoming non-batched SMTP
589channel is open, it swallows the rest of the incoming message if in the DATA
590phase, sends the reply string, and gives an error to all subsequent commands
591except QUIT. The existence of an SMTP call is detected by the non-NULLness of
592smtp_in.
593
594Argument: SMTP reply string to send, excluding the code
595Returns: nothing
596*/
597
598void
599smtp_closedown(uschar *message)
600{
601if (smtp_in == NULL || smtp_batched_input) return;
602receive_swallow_smtp();
603smtp_printf("421 %s\r\n", message);
604
605for (;;)
606 {
607 switch(smtp_read_command(FALSE))
608 {
609 case EOF_CMD:
610 return;
611
612 case QUIT_CMD:
613 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
614 mac_smtp_fflush();
615 return;
616
617 case RSET_CMD:
618 smtp_printf("250 Reset OK\r\n");
619 break;
620
621 default:
622 smtp_printf("421 %s\r\n", message);
623 break;
624 }
625 }
626}
627
628
629
630
631/*************************************************
632* Set up connection info for logging *
633*************************************************/
634
635/* This function is called when logging information about an SMTP connection.
636It sets up appropriate source information, depending on the type of connection.
dac79d3e
PH
637If sender_fullhost is NULL, we are at a very early stage of the connection;
638just use the IP address.
059ec3d9
PH
639
640Argument: none
641Returns: a string describing the connection
642*/
643
644uschar *
645smtp_get_connection_info(void)
646{
dac79d3e
PH
647uschar *hostname = (sender_fullhost == NULL)?
648 sender_host_address : sender_fullhost;
649
059ec3d9 650if (host_checking)
dac79d3e 651 return string_sprintf("SMTP connection from %s", hostname);
059ec3d9
PH
652
653if (sender_host_unknown || sender_host_notsocket)
654 return string_sprintf("SMTP connection from %s", sender_ident);
655
656if (is_inetd)
dac79d3e 657 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
059ec3d9
PH
658
659if ((log_extra_selector & LX_incoming_interface) != 0 &&
660 interface_address != NULL)
dac79d3e 661 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
059ec3d9
PH
662 interface_address, interface_port);
663
dac79d3e 664return string_sprintf("SMTP connection from %s", hostname);
059ec3d9
PH
665}
666
667
668
669/*************************************************
670* Check HELO line and set sender_helo_name *
671*************************************************/
672
673/* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
674the domain name of the sending host, or an ip literal in square brackets. The
675arrgument is placed in sender_helo_name, which is in malloc store, because it
676must persist over multiple incoming messages. If helo_accept_junk is set, this
677host is permitted to send any old junk (needed for some broken hosts).
678Otherwise, helo_allow_chars can be used for rogue characters in general
679(typically people want to let in underscores).
680
681Argument:
682 s the data portion of the line (already past any white space)
683
684Returns: TRUE or FALSE
685*/
686
687static BOOL
688check_helo(uschar *s)
689{
690uschar *start = s;
691uschar *end = s + Ustrlen(s);
692BOOL yield = helo_accept_junk;
693
694/* Discard any previous helo name */
695
696if (sender_helo_name != NULL)
697 {
698 store_free(sender_helo_name);
699 sender_helo_name = NULL;
700 }
701
702/* Skip tests if junk is permitted. */
703
704if (!yield)
705 {
706 /* Allow the new standard form for IPv6 address literals, namely,
707 [IPv6:....], and because someone is bound to use it, allow an equivalent
708 IPv4 form. Allow plain addresses as well. */
709
710 if (*s == '[')
711 {
712 if (end[-1] == ']')
713 {
714 end[-1] = 0;
715 if (strncmpic(s, US"[IPv6:", 6) == 0)
716 yield = (string_is_ip_address(s+6, NULL) == 6);
717 else if (strncmpic(s, US"[IPv4:", 6) == 0)
718 yield = (string_is_ip_address(s+6, NULL) == 4);
719 else
720 yield = (string_is_ip_address(s+1, NULL) != 0);
721 end[-1] = ']';
722 }
723 }
724
725 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
726 that have been configured (usually underscore - sigh). */
727
728 else if (*s != 0)
729 {
730 yield = TRUE;
731 while (*s != 0)
732 {
733 if (!isalnum(*s) && *s != '.' && *s != '-' &&
734 Ustrchr(helo_allow_chars, *s) == NULL)
735 {
736 yield = FALSE;
737 break;
738 }
739 s++;
740 }
741 }
742 }
743
744/* Save argument if OK */
745
746if (yield) sender_helo_name = string_copy_malloc(start);
747return yield;
748}
749
750
751
752
753
754/*************************************************
755* Extract SMTP command option *
756*************************************************/
757
3ee512ff 758/* This function picks the next option setting off the end of smtp_cmd_argument. It
059ec3d9
PH
759is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
760things that can appear there.
761
762Arguments:
763 name point this at the name
764 value point this at the data string
765
766Returns: TRUE if found an option
767*/
768
769static BOOL
770extract_option(uschar **name, uschar **value)
771{
772uschar *n;
3ee512ff 773uschar *v = smtp_cmd_argument + Ustrlen(smtp_cmd_argument) -1;
059ec3d9
PH
774while (isspace(*v)) v--;
775v[1] = 0;
776
3ee512ff 777while (v > smtp_cmd_argument && *v != '=' && !isspace(*v)) v--;
059ec3d9
PH
778if (*v != '=') return FALSE;
779
780n = v;
781while(isalpha(n[-1])) n--;
782
783if (n[-1] != ' ') return FALSE;
784
785n[-1] = 0;
786*name = n;
787*v++ = 0;
788*value = v;
789return TRUE;
790}
791
792
793
794
795
059ec3d9
PH
796/*************************************************
797* Reset for new message *
798*************************************************/
799
800/* This function is called whenever the SMTP session is reset from
801within either of the setup functions.
802
803Argument: the stacking pool storage reset point
804Returns: nothing
805*/
806
807static void
808smtp_reset(void *reset_point)
809{
059ec3d9
PH
810store_reset(reset_point);
811recipients_list = NULL;
812rcpt_count = rcpt_defer_count = rcpt_fail_count =
813 raw_recipients_count = recipients_count = recipients_list_max = 0;
2e0c1448 814message_linecount = 0;
059ec3d9 815message_size = -1;
71fafd95 816acl_added_headers = NULL;
059ec3d9 817queue_only_policy = FALSE;
69358f02 818deliver_freeze = FALSE; /* Can be set by ACL */
6a3f1455 819freeze_tell = freeze_tell_config; /* Can be set by ACL */
29aba418 820fake_response = OK; /* Can be set by ACL */
6951ac6c 821#ifdef WITH_CONTENT_SCAN
8523533c
TK
822no_mbox_unspool = FALSE; /* Can be set by ACL */
823#endif
69358f02 824submission_mode = FALSE; /* Can be set by ACL */
8800895a 825suppress_local_fixups = FALSE; /* Can be set by ACL */
69358f02
PH
826active_local_from_check = local_from_check; /* Can be set by ACL */
827active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
059ec3d9 828sender_address = NULL;
2fe1a124 829submission_name = NULL; /* Can be set by ACL */
059ec3d9
PH
830raw_sender = NULL; /* After SMTP rewrite, before qualifying */
831sender_address_unrewritten = NULL; /* Set only after verify rewrite */
832sender_verified_list = NULL; /* No senders verified */
833memset(sender_address_cache, 0, sizeof(sender_address_cache));
834memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
835authenticated_sender = NULL;
8523533c
TK
836#ifdef EXPERIMENTAL_BRIGHTMAIL
837bmi_run = 0;
838bmi_verdicts = NULL;
839#endif
fb2274d4
TK
840#ifdef EXPERIMENTAL_DOMAINKEYS
841dk_do_verify = 0;
842#endif
8523533c
TK
843#ifdef EXPERIMENTAL_SPF
844spf_header_comment = NULL;
845spf_received = NULL;
8e669ac1 846spf_result = NULL;
8523533c
TK
847spf_smtp_comment = NULL;
848#endif
059ec3d9
PH
849body_linecount = body_zerocount = 0;
850
870f6ba8
TF
851sender_rate = sender_rate_limit = sender_rate_period = NULL;
852ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
853 /* Note that ratelimiters_conn persists across resets. */
854
38a0a95f 855/* Reset message ACL variables */
47ca6d6c 856
38a0a95f 857acl_var_m = NULL;
059ec3d9
PH
858
859/* The message body variables use malloc store. They may be set if this is
860not the first message in an SMTP session and the previous message caused them
861to be referenced in an ACL. */
862
863if (message_body != NULL)
864 {
865 store_free(message_body);
866 message_body = NULL;
867 }
868
869if (message_body_end != NULL)
870 {
871 store_free(message_body_end);
872 message_body_end = NULL;
873 }
874
875/* Warning log messages are also saved in malloc store. They are saved to avoid
876repetition in the same message, but it seems right to repeat them for different
877messagess. */
878
879while (acl_warn_logged != NULL)
880 {
881 string_item *this = acl_warn_logged;
882 acl_warn_logged = acl_warn_logged->next;
883 store_free(this);
884 }
885}
886
887
888
889
890
891/*************************************************
892* Initialize for incoming batched SMTP message *
893*************************************************/
894
895/* This function is called from smtp_setup_msg() in the case when
896smtp_batched_input is true. This happens when -bS is used to pass a whole batch
897of messages in one file with SMTP commands between them. All errors must be
898reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
899relevant. After an error on a sender, or an invalid recipient, the remainder
900of the message is skipped. The value of received_protocol is already set.
901
902Argument: none
903Returns: > 0 message successfully started (reached DATA)
904 = 0 QUIT read or end of file reached
905 < 0 should not occur
906*/
907
908static int
909smtp_setup_batch_msg(void)
910{
911int done = 0;
912void *reset_point = store_get(0);
913
914/* Save the line count at the start of each transaction - single commands
915like HELO and RSET count as whole transactions. */
916
917bsmtp_transaction_linecount = receive_linecount;
918
919if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
920
921smtp_reset(reset_point); /* Reset for start of message */
922
923/* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
924value. The values are 2 larger than the required yield of the function. */
925
926while (done <= 0)
927 {
928 uschar *errmess;
929 uschar *recipient = NULL;
930 int start, end, sender_domain, recipient_domain;
931
932 switch(smtp_read_command(FALSE))
933 {
934 /* The HELO/EHLO commands set sender_address_helo if they have
935 valid data; otherwise they are ignored, except that they do
936 a reset of the state. */
937
938 case HELO_CMD:
939 case EHLO_CMD:
940
3ee512ff 941 check_helo(smtp_cmd_argument);
059ec3d9
PH
942 /* Fall through */
943
944 case RSET_CMD:
945 smtp_reset(reset_point);
946 bsmtp_transaction_linecount = receive_linecount;
947 break;
948
949
950 /* The MAIL FROM command requires an address as an operand. All we
951 do here is to parse it for syntactic correctness. The form "<>" is
952 a special case which converts into an empty string. The start/end
953 pointers in the original are not used further for this address, as
954 it is the canonical extracted address which is all that is kept. */
955
956 case MAIL_CMD:
957 if (sender_address != NULL)
958 /* The function moan_smtp_batch() does not return. */
3ee512ff 959 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
059ec3d9 960
3ee512ff 961 if (smtp_cmd_argument[0] == 0)
059ec3d9 962 /* The function moan_smtp_batch() does not return. */
3ee512ff 963 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
059ec3d9
PH
964
965 /* Reset to start of message */
966
967 smtp_reset(reset_point);
968
969 /* Apply SMTP rewrite */
970
971 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3ee512ff
PH
972 rewrite_one(smtp_cmd_argument, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
973 US"", global_rewrite_rules) : smtp_cmd_argument;
059ec3d9
PH
974
975 /* Extract the address; the TRUE flag allows <> as valid */
976
977 raw_sender =
978 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
979 TRUE);
980
981 if (raw_sender == NULL)
982 /* The function moan_smtp_batch() does not return. */
3ee512ff 983 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
059ec3d9
PH
984
985 sender_address = string_copy(raw_sender);
986
987 /* Qualify unqualified sender addresses if permitted to do so. */
988
989 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
990 {
991 if (allow_unqualified_sender)
992 {
993 sender_address = rewrite_address_qualify(sender_address, FALSE);
994 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
995 "and rewritten\n", raw_sender);
996 }
997 /* The function moan_smtp_batch() does not return. */
3ee512ff 998 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
059ec3d9
PH
999 "a domain");
1000 }
1001 break;
1002
1003
1004 /* The RCPT TO command requires an address as an operand. All we do
1005 here is to parse it for syntactic correctness. There may be any number
1006 of RCPT TO commands, specifying multiple senders. We build them all into
1007 a data structure that is in argc/argv format. The start/end values
1008 given by parse_extract_address are not used, as we keep only the
1009 extracted address. */
1010
1011 case RCPT_CMD:
1012 if (sender_address == NULL)
1013 /* The function moan_smtp_batch() does not return. */
3ee512ff 1014 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
059ec3d9 1015
3ee512ff 1016 if (smtp_cmd_argument[0] == 0)
059ec3d9 1017 /* The function moan_smtp_batch() does not return. */
3ee512ff 1018 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
059ec3d9
PH
1019
1020 /* Check maximum number allowed */
1021
1022 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1023 /* The function moan_smtp_batch() does not return. */
3ee512ff 1024 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
059ec3d9
PH
1025 recipients_max_reject? "552": "452");
1026
1027 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1028 recipient address */
1029
1030 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3ee512ff
PH
1031 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
1032 global_rewrite_rules) : smtp_cmd_argument;
059ec3d9
PH
1033
1034 /* rfc821_domains = TRUE; << no longer needed */
1035 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1036 &recipient_domain, FALSE);
1037 /* rfc821_domains = FALSE; << no longer needed */
1038
1039 if (recipient == NULL)
1040 /* The function moan_smtp_batch() does not return. */
3ee512ff 1041 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
059ec3d9
PH
1042
1043 /* If the recipient address is unqualified, qualify it if permitted. Then
1044 add it to the list of recipients. */
1045
1046 if (recipient_domain == 0)
1047 {
1048 if (allow_unqualified_recipient)
1049 {
1050 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1051 recipient);
1052 recipient = rewrite_address_qualify(recipient, TRUE);
1053 }
1054 /* The function moan_smtp_batch() does not return. */
3ee512ff 1055 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
059ec3d9
PH
1056 "a domain");
1057 }
1058 receive_add_recipient(recipient, -1);
1059 break;
1060
1061
1062 /* The DATA command is legal only if it follows successful MAIL FROM
1063 and RCPT TO commands. This function is complete when a valid DATA
1064 command is encountered. */
1065
1066 case DATA_CMD:
1067 if (sender_address == NULL || recipients_count <= 0)
1068 {
1069 /* The function moan_smtp_batch() does not return. */
1070 if (sender_address == NULL)
3ee512ff 1071 moan_smtp_batch(smtp_cmd_buffer,
059ec3d9
PH
1072 "503 MAIL FROM:<sender> command must precede DATA");
1073 else
3ee512ff 1074 moan_smtp_batch(smtp_cmd_buffer,
059ec3d9
PH
1075 "503 RCPT TO:<recipient> must precede DATA");
1076 }
1077 else
1078 {
1079 done = 3; /* DATA successfully achieved */
1080 message_ended = END_NOTENDED; /* Indicate in middle of message */
1081 }
1082 break;
1083
1084
1085 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1086
1087 case VRFY_CMD:
1088 case EXPN_CMD:
1089 case HELP_CMD:
1090 case NOOP_CMD:
1091 case ETRN_CMD:
1092 bsmtp_transaction_linecount = receive_linecount;
1093 break;
1094
1095
1096 case EOF_CMD:
1097 case QUIT_CMD:
1098 done = 2;
1099 break;
1100
1101
1102 case BADARG_CMD:
1103 /* The function moan_smtp_batch() does not return. */
3ee512ff 1104 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
059ec3d9
PH
1105 break;
1106
1107
1108 case BADCHAR_CMD:
1109 /* The function moan_smtp_batch() does not return. */
3ee512ff 1110 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
059ec3d9
PH
1111 break;
1112
1113
1114 default:
1115 /* The function moan_smtp_batch() does not return. */
3ee512ff 1116 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
059ec3d9
PH
1117 break;
1118 }
1119 }
1120
1121return done - 2; /* Convert yield values */
1122}
1123
1124
1125
1126
1127/*************************************************
1128* Start an SMTP session *
1129*************************************************/
1130
1131/* This function is called at the start of an SMTP session. Thereafter,
1132smtp_setup_msg() is called to initiate each separate message. This
1133function does host-specific testing, and outputs the banner line.
1134
1135Arguments: none
1136Returns: FALSE if the session can not continue; something has
1137 gone wrong, or the connection to the host is blocked
1138*/
1139
1140BOOL
1141smtp_start_session(void)
1142{
1143int size = 256;
38a0a95f 1144int ptr;
059ec3d9
PH
1145uschar *p, *s, *ss;
1146
00f00ca5
PH
1147/* Default values for certain variables */
1148
059ec3d9
PH
1149helo_seen = esmtp = helo_accept_junk = FALSE;
1150count_nonmail = TRUE_UNSET;
1151synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1152smtp_delay_mail = smtp_rlm_base;
1153auth_advertised = FALSE;
1154pipelining_advertised = FALSE;
1155sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1156
1157memset(sender_host_cache, 0, sizeof(sender_host_cache));
1158
33d73e3b
PH
1159/* If receiving by -bs from a trusted user, or testing with -bh, we allow
1160authentication settings from -oMaa to remain in force. */
1161
1162if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
059ec3d9
PH
1163authenticated_by = NULL;
1164
1165#ifdef SUPPORT_TLS
1166tls_cipher = tls_peerdn = NULL;
1167tls_advertised = FALSE;
1168#endif
1169
1170/* Reset ACL connection variables */
1171
38a0a95f 1172acl_var_c = NULL;
059ec3d9 1173
3ee512ff
PH
1174/* Allow for trailing 0 in the command buffer. */
1175
1176smtp_cmd_buffer = (uschar *)malloc(smtp_cmd_buffer_size + 1);
1177if (smtp_cmd_buffer == NULL)
059ec3d9
PH
1178 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1179 "malloc() failed for SMTP command buffer");
1180
1181/* For batched input, the protocol setting can be overridden from the
1182command line by a trusted caller. */
1183
1184if (smtp_batched_input)
1185 {
1186 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1187 }
1188
1189/* For non-batched SMTP input, the protocol setting is forced here. It will be
1190reset later if any of EHLO/AUTH/STARTTLS are received. */
1191
1192else
1193 received_protocol =
1194 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1195
1196/* Set up the buffer for inputting using direct read() calls, and arrange to
1197call the local functions instead of the standard C ones. */
1198
1199smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1200if (smtp_inbuffer == NULL)
1201 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1202receive_getc = smtp_getc;
1203receive_ungetc = smtp_ungetc;
1204receive_feof = smtp_feof;
1205receive_ferror = smtp_ferror;
1206smtp_inptr = smtp_inend = smtp_inbuffer;
1207smtp_had_eof = smtp_had_error = 0;
1208
1209/* Set up the message size limit; this may be host-specific */
1210
d45b1de8
PH
1211thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1212if (expand_string_message != NULL)
059ec3d9
PH
1213 {
1214 if (thismessage_size_limit == -1)
1215 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1216 "%s", expand_string_message);
1217 else
1218 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1219 "%s", expand_string_message);
1220 smtp_closedown(US"Temporary local problem - please try later");
1221 return FALSE;
1222 }
1223
1224/* When a message is input locally via the -bs or -bS options, sender_host_
1225unknown is set unless -oMa was used to force an IP address, in which case it
1226is checked like a real remote connection. When -bs is used from inetd, this
1227flag is not set, causing the sending host to be checked. The code that deals
1228with IP source routing (if configured) is never required for -bs or -bS and
1229the flag sender_host_notsocket is used to suppress it.
1230
1231If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1232reserve for certain hosts and/or networks. */
1233
1234if (!sender_host_unknown)
1235 {
1236 int rc;
1237 BOOL reserved_host = FALSE;
1238
1239 /* Look up IP options (source routing info) on the socket if this is not an
1240 -oMa "host", and if any are found, log them and drop the connection.
1241
1242 Linux (and others now, see below) is different to everyone else, so there
1243 has to be some conditional compilation here. Versions of Linux before 2.1.15
1244 used a structure whose name was "options". Somebody finally realized that
1245 this name was silly, and it got changed to "ip_options". I use the
1246 newer name here, but there is a fudge in the script that sets up os.h
1247 to define a macro in older Linux systems.
1248
1249 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1250 glibc 2, which has chosen ip_opts for the structure name. This is now
1251 really a glibc thing rather than a Linux thing, so the condition name
1252 has been changed to reflect this. It is relevant also to GNU/Hurd.
1253
1254 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1255 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1256 a special macro defined in the os.h file.
1257
1258 Some DGUX versions on older hardware appear not to support IP options at
1259 all, so there is now a general macro which can be set to cut out this
1260 support altogether.
1261
1262 How to do this properly in IPv6 is not yet known. */
1263
1264 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1265
1266 #ifdef GLIBC_IP_OPTIONS
1267 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1268 #define OPTSTYLE 1
1269 #else
1270 #define OPTSTYLE 2
1271 #endif
1272 #elif defined DARWIN_IP_OPTIONS
1273 #define OPTSTYLE 2
1274 #else
1275 #define OPTSTYLE 3
1276 #endif
1277
1278 if (!host_checking && !sender_host_notsocket)
1279 {
1280 #if OPTSTYLE == 1
36a3b041 1281 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
059ec3d9
PH
1282 struct ip_options *ipopt = store_get(optlen);
1283 #elif OPTSTYLE == 2
1284 struct ip_opts ipoptblock;
1285 struct ip_opts *ipopt = &ipoptblock;
36a3b041 1286 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
059ec3d9
PH
1287 #else
1288 struct ipoption ipoptblock;
1289 struct ipoption *ipopt = &ipoptblock;
36a3b041 1290 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
059ec3d9
PH
1291 #endif
1292
1293 /* Occasional genuine failures of getsockopt() have been seen - for
1294 example, "reset by peer". Therefore, just log and give up on this
1295 call, unless the error is ENOPROTOOPT. This error is given by systems
1296 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1297 of writing. So for that error, carry on - we just can't do an IP options
1298 check. */
1299
1300 DEBUG(D_receive) debug_printf("checking for IP options\n");
1301
1302 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1303 &optlen) < 0)
1304 {
1305 if (errno != ENOPROTOOPT)
1306 {
1307 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1308 host_and_ident(FALSE), strerror(errno));
1309 smtp_printf("451 SMTP service not available\r\n");
1310 return FALSE;
1311 }
1312 }
1313
1314 /* Deal with any IP options that are set. On the systems I have looked at,
1315 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1316 more logging data than will fit in big_buffer. Nevertheless, after somebody
1317 questioned this code, I've added in some paranoid checking. */
1318
1319 else if (optlen > 0)
1320 {
1321 uschar *p = big_buffer;
1322 uschar *pend = big_buffer + big_buffer_size;
1323 uschar *opt, *adptr;
1324 int optcount;
1325 struct in_addr addr;
1326
1327 #if OPTSTYLE == 1
1328 uschar *optstart = (uschar *)(ipopt->__data);
1329 #elif OPTSTYLE == 2
1330 uschar *optstart = (uschar *)(ipopt->ip_opts);
1331 #else
1332 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1333 #endif
1334
1335 DEBUG(D_receive) debug_printf("IP options exist\n");
1336
1337 Ustrcpy(p, "IP options on incoming call:");
1338 p += Ustrlen(p);
1339
1340 for (opt = optstart; opt != NULL &&
1341 opt < (uschar *)(ipopt) + optlen;)
1342 {
1343 switch (*opt)
1344 {
1345 case IPOPT_EOL:
1346 opt = NULL;
1347 break;
1348
1349 case IPOPT_NOP:
1350 opt++;
1351 break;
1352
1353 case IPOPT_SSRR:
1354 case IPOPT_LSRR:
1355 if (!string_format(p, pend-p, " %s [@%s",
1356 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1357 #if OPTSTYLE == 1
1358 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1359 #elif OPTSTYLE == 2
1360 inet_ntoa(ipopt->ip_dst)))
1361 #else
1362 inet_ntoa(ipopt->ipopt_dst)))
1363 #endif
1364 {
1365 opt = NULL;
1366 break;
1367 }
1368
1369 p += Ustrlen(p);
1370 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1371 adptr = opt + 3;
1372 while (optcount-- > 0)
1373 {
1374 memcpy(&addr, adptr, sizeof(addr));
1375 if (!string_format(p, pend - p - 1, "%s%s",
1376 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1377 {
1378 opt = NULL;
1379 break;
1380 }
1381 p += Ustrlen(p);
1382 adptr += sizeof(struct in_addr);
1383 }
1384 *p++ = ']';
1385 opt += opt[1];
1386 break;
1387
1388 default:
1389 {
1390 int i;
1391 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1392 Ustrcat(p, "[ ");
1393 p += 2;
1394 for (i = 0; i < opt[1]; i++)
1395 {
1396 sprintf(CS p, "%2.2x ", opt[i]);
1397 p += 3;
1398 }
1399 *p++ = ']';
1400 }
1401 opt += opt[1];
1402 break;
1403 }
1404 }
1405
1406 *p = 0;
1407 log_write(0, LOG_MAIN, "%s", big_buffer);
1408
1409 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1410
1411 log_write(0, LOG_MAIN|LOG_REJECT,
1412 "connection from %s refused (IP options)", host_and_ident(FALSE));
1413
1414 smtp_printf("554 SMTP service not available\r\n");
1415 return FALSE;
1416 }
1417
1418 /* Length of options = 0 => there are no options */
1419
1420 else DEBUG(D_receive) debug_printf("no IP options found\n");
1421 }
1422 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1423
1424 /* Set keep-alive in socket options. The option is on by default. This
1425 setting is an attempt to get rid of some hanging connections that stick in
1426 read() when the remote end (usually a dialup) goes away. */
1427
1428 if (smtp_accept_keepalive && !sender_host_notsocket)
1429 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1430
1431 /* If the current host matches host_lookup, set the name by doing a
1432 reverse lookup. On failure, sender_host_name will be NULL and
1433 host_lookup_failed will be TRUE. This may or may not be serious - optional
1434 checks later. */
1435
1436 if (verify_check_host(&host_lookup) == OK)
1437 {
1438 (void)host_name_lookup();
1439 host_build_sender_fullhost();
1440 }
1441
1442 /* Delay this until we have the full name, if it is looked up. */
1443
1444 set_process_info("handling incoming connection from %s",
1445 host_and_ident(FALSE));
1446
1447 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1448 smtps port for use with older style SSL MTAs. */
1449
1450 #ifdef SUPPORT_TLS
1451 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1452 return FALSE;
1453 #endif
1454
1455 /* Test for explicit connection rejection */
1456
1457 if (verify_check_host(&host_reject_connection) == OK)
1458 {
1459 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1460 "from %s (host_reject_connection)", host_and_ident(FALSE));
1461 smtp_printf("554 SMTP service not available\r\n");
1462 return FALSE;
1463 }
1464
afb3eaaf
PH
1465 /* Test with TCP Wrappers if so configured. There is a problem in that
1466 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1467 such as disks dying. In these cases, it is desirable to reject with a 4xx
1468 error instead of a 5xx error. There isn't a "right" way to detect such
1469 problems. The following kludge is used: errno is zeroed before calling
1470 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1471 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1472 not exist). */
059ec3d9
PH
1473
1474 #ifdef USE_TCP_WRAPPERS
afb3eaaf 1475 errno = 0;
059ec3d9
PH
1476 if (!hosts_ctl("exim",
1477 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1478 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1479 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1480 {
afb3eaaf
PH
1481 if (errno == 0 || errno == ENOENT)
1482 {
1483 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1484 log_write(L_connection_reject,
1485 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1486 "(tcp wrappers)", host_and_ident(FALSE));
1487 smtp_printf("554 SMTP service not available\r\n");
1488 }
1489 else
1490 {
1491 int save_errno = errno;
1492 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1493 "errno value %d\n", save_errno);
1494 log_write(L_connection_reject,
1495 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1496 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1497 smtp_printf("451 Temporary local problem - please try later\r\n");
1498 }
059ec3d9
PH
1499 return FALSE;
1500 }
1501 #endif
1502
1503 /* Check for reserved slots. Note that the count value doesn't include
1504 this process, as it gets upped in the parent process. */
1505
1506 if (smtp_accept_max > 0 &&
1507 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1508 {
1509 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1510 {
1511 log_write(L_connection_reject,
1512 LOG_MAIN, "temporarily refused connection from %s: not in "
1513 "reserve list: connected=%d max=%d reserve=%d%s",
1514 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1515 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1516 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1517 "please try again later\r\n", smtp_active_hostname);
1518 return FALSE;
1519 }
1520 reserved_host = TRUE;
1521 }
1522
1523 /* If a load level above which only messages from reserved hosts are
1524 accepted is set, check the load. For incoming calls via the daemon, the
1525 check is done in the superior process if there are no reserved hosts, to
1526 save a fork. In all cases, the load average will already be available
1527 in a global variable at this point. */
1528
1529 if (smtp_load_reserve >= 0 &&
1530 load_average > smtp_load_reserve &&
1531 !reserved_host &&
1532 verify_check_host(&smtp_reserve_hosts) != OK)
1533 {
1534 log_write(L_connection_reject,
1535 LOG_MAIN, "temporarily refused connection from %s: not in "
1536 "reserve list and load average = %.2f", host_and_ident(FALSE),
1537 (double)load_average/1000.0);
1538 smtp_printf("421 %s: Too much load; please try again later\r\n",
1539 smtp_active_hostname);
1540 return FALSE;
1541 }
1542
1543 /* Determine whether unqualified senders or recipients are permitted
1544 for this host. Unfortunately, we have to do this every time, in order to
1545 set the flags so that they can be inspected when considering qualifying
1546 addresses in the headers. For a site that permits no qualification, this
1547 won't take long, however. */
1548
1549 allow_unqualified_sender =
1550 verify_check_host(&sender_unqualified_hosts) == OK;
1551
1552 allow_unqualified_recipient =
1553 verify_check_host(&recipient_unqualified_hosts) == OK;
1554
1555 /* Determine whether HELO/EHLO is required for this host. The requirement
1556 can be hard or soft. */
1557
1558 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1559 if (!helo_required)
1560 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1561
1562 /* Determine whether this hosts is permitted to send syntactic junk
1563 after a HELO or EHLO command. */
1564
1565 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1566 }
1567
1568/* For batch SMTP input we are now done. */
1569
1570if (smtp_batched_input) return TRUE;
1571
1572/* Run the ACL if it exists */
1573
1574if (acl_smtp_connect != NULL)
1575 {
1576 int rc;
1577 uschar *user_msg, *log_msg;
64ffc24f 1578 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
059ec3d9
PH
1579 &log_msg);
1580 if (rc != OK)
1581 {
1582 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1583 return FALSE;
1584 }
1585 }
1586
1587/* Output the initial message for a two-way SMTP connection. It may contain
1588newlines, which then cause a multi-line response to be given. */
1589
1590s = expand_string(smtp_banner);
1591if (s == NULL)
1592 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1593 "failed: %s", smtp_banner, expand_string_message);
1594
1595/* Remove any terminating newlines; might as well remove trailing space too */
1596
1597p = s + Ustrlen(s);
1598while (p > s && isspace(p[-1])) p--;
1599*p = 0;
1600
1601/* It seems that CC:Mail is braindead, and assumes that the greeting message
1602is all contained in a single IP packet. The original code wrote out the
1603greeting using several calls to fprint/fputc, and on busy servers this could
1604cause it to be split over more than one packet - which caused CC:Mail to fall
1605over when it got the second part of the greeting after sending its first
1606command. Sigh. To try to avoid this, build the complete greeting message
1607first, and output it in one fell swoop. This gives a better chance of it
1608ending up as a single packet. */
1609
1610ss = store_get(size);
1611ptr = 0;
1612
1613p = s;
1614do /* At least once, in case we have an empty string */
1615 {
1616 int len;
1617 uschar *linebreak = Ustrchr(p, '\n');
1618 if (linebreak == NULL)
1619 {
1620 len = Ustrlen(p);
1621 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1622 }
1623 else
1624 {
1625 len = linebreak - p;
1626 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1627 }
1628 ss = string_cat(ss, &size, &ptr, p, len);
1629 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1630 p += len;
1631 if (linebreak != NULL) p++;
1632 }
1633while (*p != 0);
1634
1635ss[ptr] = 0; /* string_cat leaves room for this */
1636
1637/* Before we write the banner, check that there is no input pending, unless
1638this synchronisation check is disabled. */
1639
1640if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1641 {
1642 fd_set fds;
1643 struct timeval tzero;
1644 tzero.tv_sec = 0;
1645 tzero.tv_usec = 0;
1646 FD_ZERO(&fds);
1647 FD_SET(fileno(smtp_in), &fds);
1648 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1649 &tzero) > 0)
1650 {
00f00ca5 1651 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
f9b9210e
PH
1652 if (rc > 0)
1653 {
1654 if (rc > 150) rc = 150;
1655 smtp_inbuffer[rc] = 0;
3af76a81 1656 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
f9b9210e
PH
1657 "synchronization error (input sent without waiting for greeting): "
1658 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1659 string_printing(smtp_inbuffer));
1660 smtp_printf("554 SMTP synchronization error\r\n");
1661 return FALSE;
1662 }
059ec3d9
PH
1663 }
1664 }
1665
1666/* Now output the banner */
1667
1668smtp_printf("%s", ss);
1669return TRUE;
1670}
1671
1672
1673
1674
1675
1676/*************************************************
1677* Handle SMTP syntax and protocol errors *
1678*************************************************/
1679
1680/* Write to the log for SMTP syntax errors in incoming commands, if configured
1681to do so. Then transmit the error response. The return value depends on the
1682number of syntax and protocol errors in this SMTP session.
1683
1684Arguments:
1685 type error type, given as a log flag bit
1686 code response code; <= 0 means don't send a response
1687 data data to reflect in the response (can be NULL)
1688 errmess the error message
1689
1690Returns: -1 limit of syntax/protocol errors NOT exceeded
1691 +1 limit of syntax/protocol errors IS exceeded
1692
1693These values fit in with the values of the "done" variable in the main
1694processing loop in smtp_setup_msg(). */
1695
1696static int
1697synprot_error(int type, int code, uschar *data, uschar *errmess)
1698{
1699int yield = -1;
1700
1701log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1702 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3ee512ff 1703 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
059ec3d9
PH
1704
1705if (++synprot_error_count > smtp_max_synprot_errors)
1706 {
1707 yield = 1;
1708 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1709 "syntax or protocol errors (last command was \"%s\")",
3ee512ff 1710 host_and_ident(FALSE), smtp_cmd_buffer);
059ec3d9
PH
1711 }
1712
1713if (code > 0)
1714 {
1715 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1716 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1717 if (yield == 1)
1718 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1719 }
1720
1721return yield;
1722}
1723
1724
1725
1726
1727/*************************************************
1728* Log incomplete transactions *
1729*************************************************/
1730
1731/* This function is called after a transaction has been aborted by RSET, QUIT,
1732connection drops or other errors. It logs the envelope information received
1733so far in order to preserve address verification attempts.
1734
1735Argument: string to indicate what aborted the transaction
1736Returns: nothing
1737*/
1738
1739static void
1740incomplete_transaction_log(uschar *what)
1741{
1742if (sender_address == NULL || /* No transaction in progress */
1743 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1744 ) return;
1745
1746/* Build list of recipients for logging */
1747
1748if (recipients_count > 0)
1749 {
1750 int i;
1751 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1752 for (i = 0; i < recipients_count; i++)
1753 raw_recipients[i] = recipients_list[i].address;
1754 raw_recipients_count = recipients_count;
1755 }
1756
1757log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1758 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1759}
1760
1761
1762
1763
1764/*************************************************
1765* Send SMTP response, possibly multiline *
1766*************************************************/
1767
1768/* There are, it seems, broken clients out there that cannot handle multiline
1769responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1770output nothing for non-final calls, and only the first line for anything else.
1771
1772Arguments:
a5bd321b
PH
1773 code SMTP code, may involve extended status codes
1774 codelen length of smtp code; uf > 3 there's an ESC
059ec3d9
PH
1775 final FALSE if the last line isn't the final line
1776 msg message text, possibly containing newlines
1777
1778Returns: nothing
1779*/
1780
1781void
a5bd321b 1782smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
059ec3d9 1783{
a5bd321b
PH
1784int esclen = 0;
1785uschar *esc = US"";
1786
059ec3d9
PH
1787if (!final && no_multiline_responses) return;
1788
a5bd321b
PH
1789if (codelen > 3)
1790 {
1791 esc = code + 4;
1792 esclen = codelen - 4;
1793 }
1794
059ec3d9
PH
1795for (;;)
1796 {
1797 uschar *nl = Ustrchr(msg, '\n');
1798 if (nl == NULL)
1799 {
a5bd321b 1800 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
059ec3d9
PH
1801 return;
1802 }
1803 else if (nl[1] == 0 || no_multiline_responses)
1804 {
a5bd321b
PH
1805 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
1806 (int)(nl - msg), msg);
059ec3d9
PH
1807 return;
1808 }
1809 else
1810 {
a5bd321b 1811 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
059ec3d9
PH
1812 msg = nl + 1;
1813 while (isspace(*msg)) msg++;
1814 }
1815 }
1816}
1817
1818
1819
1820
1821/*************************************************
1822* Handle an ACL failure *
1823*************************************************/
1824
1825/* This function is called when acl_check() fails. As well as calls from within
1826this module, it is called from receive.c for an ACL after DATA. It sorts out
1827logging the incident, and sets up the error response. A message containing
1828newlines is turned into a multiline SMTP response, but for logging, only the
1829first line is used.
1830
a5bd321b
PH
1831There's a table of default permanent failure response codes to use in
1832globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
1833defaults disabled in Exim. However, discussion in connection with RFC 821bis
1834(aka RFC 2821) has concluded that the response should be 252 in the disabled
1835state, because there are broken clients that try VRFY before RCPT. A 5xx
1836response should be given only when the address is positively known to be
1837undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
1838503.
1839
1840From Exim 4.63, it is possible to override the response code details by
1841providing a suitable response code string at the start of the message provided
1842in user_msg. The code's first digit is checked for validity.
059ec3d9
PH
1843
1844Arguments:
1845 where where the ACL was called from
1846 rc the failure code
1847 user_msg a message that can be included in an SMTP response
1848 log_msg a message for logging
1849
1850Returns: 0 in most cases
1851 2 if the failure code was FAIL_DROP, in which case the
1852 SMTP connection should be dropped (this value fits with the
1853 "done" variable in smtp_setup_msg() below)
1854*/
1855
1856int
1857smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1858{
059ec3d9 1859BOOL drop = rc == FAIL_DROP;
a5bd321b
PH
1860int codelen = 3;
1861int ovector[3];
1862uschar *smtp_code;
059ec3d9
PH
1863uschar *lognl;
1864uschar *sender_info = US"";
64ffc24f 1865uschar *what =
8523533c 1866#ifdef WITH_CONTENT_SCAN
64ffc24f 1867 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
8e669ac1 1868#endif
64ffc24f
PH
1869 (where == ACL_WHERE_PREDATA)? US"DATA" :
1870 (where == ACL_WHERE_DATA)? US"after DATA" :
3ee512ff 1871 (smtp_cmd_argument == NULL)?
64ffc24f 1872 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
3ee512ff 1873 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_argument);
059ec3d9
PH
1874
1875if (drop) rc = FAIL;
1876
a5bd321b
PH
1877/* Set the default SMTP code */
1878
1879smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
1880
1881/* Check a user message for starting with a response code and optionally an
1882extended status code. If found, check that the first digit is valid, and if so,
1883use it instead of the default code. */
1884
1885if (user_msg != NULL)
1886 {
1887 int n = pcre_exec(regex_smtp_code, NULL, CS user_msg, Ustrlen(user_msg), 0,
1888 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
1889 if (n >= 0)
1890 {
1891 if (user_msg[0] != smtp_code[0])
1892 {
1893 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
1894 "incorrect digit (expected %c) in \"%s\"", smtp_code[0], user_msg);
1895
1896 /* If log_msg == user_msg (the default set in acl.c if no log message is
1897 specified, we must adjust the log message to show the code that is
1898 actually going to be used. */
1899
1900 if (log_msg == user_msg)
1901 log_msg = string_sprintf("%s %s", smtp_code, log_msg + ovector[1]);
1902 }
1903 else
1904 {
1905 smtp_code = user_msg;
1906 codelen = ovector[1]; /* Includes final space */
1907 }
1908 user_msg += ovector[1]; /* Chop the code off the message */
1909 }
1910 }
1911
059ec3d9
PH
1912/* We used to have sender_address here; however, there was a bug that was not
1913updating sender_address after a rewrite during a verify. When this bug was
1914fixed, sender_address at this point became the rewritten address. I'm not sure
1915this is what should be logged, so I've changed to logging the unrewritten
1916address to retain backward compatibility. */
1917
8523533c 1918#ifndef WITH_CONTENT_SCAN
059ec3d9 1919if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
8523533c
TK
1920#else
1921if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1922#endif
059ec3d9
PH
1923 {
1924 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1925 sender_address_unrewritten : sender_address);
1926 }
1927
1928/* If there's been a sender verification failure with a specific message, and
1929we have not sent a response about it yet, do so now, as a preliminary line for
278c6e6c
PH
1930failures, but not defers. However, always log it for defer, and log it for fail
1931unless the sender_verify_fail log selector has been turned off. */
059ec3d9
PH
1932
1933if (sender_verified_failed != NULL &&
1934 !testflag(sender_verified_failed, af_sverify_told))
1935 {
1936 setflag(sender_verified_failed, af_sverify_told);
1937
278c6e6c
PH
1938 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
1939 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1940 host_and_ident(TRUE),
1941 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
1942 sender_verified_failed->address,
1943 (sender_verified_failed->message == NULL)? US"" :
1944 string_sprintf(": %s", sender_verified_failed->message));
059ec3d9
PH
1945
1946 if (rc == FAIL && sender_verified_failed->user_message != NULL)
a5bd321b 1947 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
059ec3d9
PH
1948 testflag(sender_verified_failed, af_verify_pmfail)?
1949 "Postmaster verification failed while checking <%s>\n%s\n"
1950 "Several RFCs state that you are required to have a postmaster\n"
1951 "mailbox for each mail domain. This host does not accept mail\n"
1952 "from domains whose servers reject the postmaster address."
1953 :
1954 testflag(sender_verified_failed, af_verify_nsfail)?
1955 "Callback setup failed while verifying <%s>\n%s\n"
1956 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1957 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1958 "RFC requirements, and stops you from receiving standard bounce\n"
1959 "messages. This host does not accept mail from domains whose servers\n"
1960 "refuse bounces."
1961 :
1962 "Verification failed for <%s>\n%s",
1963 sender_verified_failed->address,
1964 sender_verified_failed->user_message));
1965 }
1966
1967/* Sort out text for logging */
1968
1969log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1970lognl = Ustrchr(log_msg, '\n');
1971if (lognl != NULL) *lognl = 0;
1972
1973/* Send permanent failure response to the command, but the code used isn't
1974always a 5xx one - see comments at the start of this function. If the original
1975rc was FAIL_DROP we drop the connection and yield 2. */
1976
a5bd321b 1977if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
059ec3d9
PH
1978 US"Administrative prohibition" : user_msg);
1979
1980/* Send temporary failure response to the command. Don't give any details,
1981unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1982verb, and for a header verify when smtp_return_error_details is set.
1983
1984This conditional logic is all somewhat of a mess because of the odd
1985interactions between temp_details and return_error_details. One day it should
1986be re-implemented in a tidier fashion. */
1987
1988else
1989 {
1990 if (acl_temp_details && user_msg != NULL)
1991 {
1992 if (smtp_return_error_details &&
1993 sender_verified_failed != NULL &&
1994 sender_verified_failed->message != NULL)
1995 {
a5bd321b 1996 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
059ec3d9 1997 }
a5bd321b 1998 smtp_respond(smtp_code, codelen, TRUE, user_msg);
059ec3d9
PH
1999 }
2000 else
a5bd321b
PH
2001 smtp_respond(smtp_code, codelen, TRUE,
2002 US"Temporary local problem - please try later");
059ec3d9
PH
2003 }
2004
6ea85e9a
PH
2005/* Log the incident to the logs that are specified by log_reject_target
2006(default main, reject). This can be empty to suppress logging of rejections. If
2007the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2008is closing if required and return 2. */
059ec3d9 2009
6ea85e9a
PH
2010if (log_reject_target != 0)
2011 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2012 host_and_ident(TRUE),
2013 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
059ec3d9
PH
2014
2015if (!drop) return 0;
2016
2017log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2018 smtp_get_connection_info());
2019return 2;
2020}
2021
2022
2023
2024
2025/*************************************************
d7b47fd0
PH
2026* Verify HELO argument *
2027*************************************************/
2028
2029/* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2030matched. It is also called from ACL processing if verify = helo is used and
2031verification was not previously tried (i.e. helo_try_verify_hosts was not
2032matched). The result of its processing is to set helo_verified and
2033helo_verify_failed. These variables should both be FALSE for this function to
2034be called.
2035
2036Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2037for IPv6 ::ffff: literals.
2038
2039Argument: none
2040Returns: TRUE if testing was completed;
2041 FALSE on a temporary failure
2042*/
2043
2044BOOL
2045smtp_verify_helo(void)
2046{
2047BOOL yield = TRUE;
2048
2049HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2050 sender_helo_name);
2051
2052if (sender_helo_name == NULL)
2053 {
2054 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2055 }
2056
d1d5595c
PH
2057/* Deal with the case of -bs without an IP address */
2058
2059else if (sender_host_address == NULL)
2060 {
2061 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2062 helo_verified = TRUE;
2063 }
2064
2065/* Deal with the more common case when there is a sending IP address */
2066
d7b47fd0
PH
2067else if (sender_helo_name[0] == '[')
2068 {
2069 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2070 Ustrlen(sender_host_address)) == 0;
2071
2072 #if HAVE_IPV6
2073 if (!helo_verified)
2074 {
2075 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2076 helo_verified = Ustrncmp(sender_helo_name + 1,
2077 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2078 }
2079 #endif
2080
2081 HDEBUG(D_receive)
2082 { if (helo_verified) debug_printf("matched host address\n"); }
2083 }
2084
2085/* Do a reverse lookup if one hasn't already given a positive or negative
2086response. If that fails, or the name doesn't match, try checking with a forward
2087lookup. */
2088
2089else
2090 {
2091 if (sender_host_name == NULL && !host_lookup_failed)
2092 yield = host_name_lookup() != DEFER;
2093
2094 /* If a host name is known, check it and all its aliases. */
2095
2096 if (sender_host_name != NULL)
2097 {
2098 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2099
2100 if (helo_verified)
2101 {
2102 HDEBUG(D_receive) debug_printf("matched host name\n");
2103 }
2104 else
2105 {
2106 uschar **aliases = sender_host_aliases;
2107 while (*aliases != NULL)
2108 {
2109 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2110 if (helo_verified) break;
2111 }
2112 HDEBUG(D_receive)
2113 {
2114 if (helo_verified)
2115 debug_printf("matched alias %s\n", *(--aliases));
2116 }
2117 }
2118 }
2119
2120 /* Final attempt: try a forward lookup of the helo name */
2121
2122 if (!helo_verified)
2123 {
2124 int rc;
2125 host_item h;
2126 h.name = sender_helo_name;
2127 h.address = NULL;
2128 h.mx = MX_NONE;
2129 h.next = NULL;
2130 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2131 sender_helo_name);
322050c2 2132 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
d7b47fd0
PH
2133 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2134 {
2135 host_item *hh = &h;
2136 while (hh != NULL)
2137 {
2138 if (Ustrcmp(hh->address, sender_host_address) == 0)
2139 {
2140 helo_verified = TRUE;
2141 HDEBUG(D_receive)
2142 debug_printf("IP address for %s matches calling address\n",
2143 sender_helo_name);
2144 break;
2145 }
2146 hh = hh->next;
2147 }
2148 }
2149 }
2150 }
2151
d1d5595c 2152if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
d7b47fd0
PH
2153return yield;
2154}
2155
2156
2157
2158
2159/*************************************************
059ec3d9
PH
2160* Initialize for SMTP incoming message *
2161*************************************************/
2162
2163/* This function conducts the initial dialogue at the start of an incoming SMTP
2164message, and builds a list of recipients. However, if the incoming message
2165is part of a batch (-bS option) a separate function is called since it would
2166be messy having tests splattered about all over this function. This function
2167therefore handles the case where interaction is occurring. The input and output
2168files are set up in smtp_in and smtp_out.
2169
2170The global recipients_list is set to point to a vector of recipient_item
2171blocks, whose number is given by recipients_count. This is extended by the
2172receive_add_recipient() function. The global variable sender_address is set to
2173the sender's address. The yield is +1 if a message has been successfully
2174started, 0 if a QUIT command was encountered or the connection was refused from
2175the particular host, or -1 if the connection was lost.
2176
2177Argument: none
2178
2179Returns: > 0 message successfully started (reached DATA)
2180 = 0 QUIT read or end of file reached or call refused
2181 < 0 lost connection
2182*/
2183
2184int
2185smtp_setup_msg(void)
2186{
2187int done = 0;
2188BOOL toomany = FALSE;
2189BOOL discarded = FALSE;
2190BOOL last_was_rej_mail = FALSE;
2191BOOL last_was_rcpt = FALSE;
2192void *reset_point = store_get(0);
2193
2194DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2195
2196/* Reset for start of new message. We allow one RSET not to be counted as a
2197nonmail command, for those MTAs that insist on sending it between every
2198message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2199TLS between messages (an Exim client may do this if it has messages queued up
2200for the host). Note: we do NOT reset AUTH at this point. */
2201
2202smtp_reset(reset_point);
2203message_ended = END_NOTSTARTED;
2204
2205cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2206cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2207cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2208#ifdef SUPPORT_TLS
2209cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2210#endif
2211
2212/* Set the local signal handler for SIGTERM - it tries to end off tidily */
2213
2214os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2215
2216/* Batched SMTP is handled in a different function. */
2217
2218if (smtp_batched_input) return smtp_setup_batch_msg();
2219
2220/* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2221value. The values are 2 larger than the required yield of the function. */
2222
2223while (done <= 0)
2224 {
2225 uschar **argv;
2226 uschar *etrn_command;
2227 uschar *etrn_serialize_key;
2228 uschar *errmess;
2229 uschar *user_msg, *log_msg;
2230 uschar *recipient = NULL;
2231 uschar *hello = NULL;
2232 uschar *set_id = NULL;
2233 uschar *s, *ss;
2234 BOOL was_rej_mail = FALSE;
2235 BOOL was_rcpt = FALSE;
2236 void (*oldsignal)(int);
2237 pid_t pid;
2238 int start, end, sender_domain, recipient_domain;
2239 int ptr, size, rc;
f78eb7c6 2240 int c, i;
059ec3d9
PH
2241 auth_instance *au;
2242
2243 switch(smtp_read_command(TRUE))
2244 {
2245 /* The AUTH command is not permitted to occur inside a transaction, and may
c46782ef
PH
2246 occur successfully only once per connection. Actually, that isn't quite
2247 true. When TLS is started, all previous information about a connection must
2248 be discarded, so a new AUTH is permitted at that time.
2249
2250 AUTH may only be used when it has been advertised. However, it seems that
2251 there are clients that send AUTH when it hasn't been advertised, some of
2252 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2253 So there's a get-out that allows this to happen.
059ec3d9
PH
2254
2255 AUTH is initially labelled as a "nonmail command" so that one occurrence
2256 doesn't get counted. We change the label here so that multiple failing
2257 AUTHS will eventually hit the nonmail threshold. */
2258
2259 case AUTH_CMD:
2260 authentication_failed = TRUE;
2261 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2262
c46782ef 2263 if (!auth_advertised && !allow_auth_unadvertised)
059ec3d9
PH
2264 {
2265 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2266 US"AUTH command used when not advertised");
2267 break;
2268 }
2269 if (sender_host_authenticated != NULL)
2270 {
2271 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2272 US"already authenticated");
2273 break;
2274 }
2275 if (sender_address != NULL)
2276 {
2277 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2278 US"not permitted in mail transaction");
2279 break;
2280 }
2281
2282 /* Check the ACL */
2283
2284 if (acl_smtp_auth != NULL)
2285 {
64ffc24f 2286 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
059ec3d9
PH
2287 if (rc != OK)
2288 {
2289 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2290 break;
2291 }
2292 }
2293
2294 /* Find the name of the requested authentication mechanism. */
2295
3ee512ff
PH
2296 s = smtp_cmd_argument;
2297 while ((c = *smtp_cmd_argument) != 0 && !isspace(c))
059ec3d9
PH
2298 {
2299 if (!isalnum(c) && c != '-' && c != '_')
2300 {
2301 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2302 US"invalid character in authentication mechanism name");
2303 goto COMMAND_LOOP;
2304 }
3ee512ff 2305 smtp_cmd_argument++;
059ec3d9
PH
2306 }
2307
2308 /* If not at the end of the line, we must be at white space. Terminate the
2309 name and move the pointer on to any data that may be present. */
2310
3ee512ff 2311 if (*smtp_cmd_argument != 0)
059ec3d9 2312 {
3ee512ff
PH
2313 *smtp_cmd_argument++ = 0;
2314 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
059ec3d9
PH
2315 }
2316
2317 /* Search for an authentication mechanism which is configured for use
c46782ef
PH
2318 as a server and which has been advertised (unless, sigh, allow_auth_
2319 unadvertised is set). */
059ec3d9
PH
2320
2321 for (au = auths; au != NULL; au = au->next)
2322 {
2323 if (strcmpic(s, au->public_name) == 0 && au->server &&
c46782ef 2324 (au->advertised || allow_auth_unadvertised)) break;
059ec3d9
PH
2325 }
2326
2327 if (au == NULL)
2328 {
2329 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2330 string_sprintf("%s authentication mechanism not supported", s));
2331 break;
2332 }
2333
f78eb7c6
PH
2334 /* Run the checking code, passing the remainder of the command line as
2335 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2336 it as the only set numerical variable. The authenticator may set $auth<n>
2337 and also set other numeric variables. The $auth<n> variables are preferred
2338 nowadays; the numerical variables remain for backwards compatibility.
059ec3d9 2339
f78eb7c6
PH
2340 Afterwards, have a go at expanding the set_id string, even if
2341 authentication failed - for bad passwords it can be useful to log the
2342 userid. On success, require set_id to expand and exist, and put it in
2343 authenticated_id. Save this in permanent store, as the working store gets
2344 reset at HELO, RSET, etc. */
2345
2346 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
059ec3d9
PH
2347 expand_nmax = 0;
2348 expand_nlength[0] = 0; /* $0 contains nothing */
2349
3ee512ff 2350 c = (au->info->servercode)(au, smtp_cmd_argument);
059ec3d9
PH
2351 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2352 expand_nmax = -1; /* Reset numeric variables */
f78eb7c6 2353 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
059ec3d9 2354
0612b098
PH
2355 /* The value of authenticated_id is stored in the spool file and printed in
2356 log lines. It must not contain binary zeros or newline characters. In
2357 normal use, it never will, but when playing around or testing, this error
2358 can (did) happen. To guard against this, ensure that the id contains only
2359 printing characters. */
2360
2361 if (set_id != NULL) set_id = string_printing(set_id);
2362
059ec3d9
PH
2363 /* For the non-OK cases, set up additional logging data if set_id
2364 is not empty. */
2365
2366 if (c != OK)
2367 {
2368 if (set_id != NULL && *set_id != 0)
2369 set_id = string_sprintf(" (set_id=%s)", set_id);
2370 else set_id = US"";
2371 }
2372
2373 /* Switch on the result */
2374
2375 switch(c)
2376 {
2377 case OK:
2378 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2379 {
2380 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2381 sender_host_authenticated = au->name;
2382 authentication_failed = FALSE;
2383 received_protocol =
2384 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2385 ((sender_host_address != NULL)? pnlocal : 0);
2386 s = ss = US"235 Authentication succeeded";
2387 authenticated_by = au;
2388 break;
2389 }
2390
2391 /* Authentication succeeded, but we failed to expand the set_id string.
2392 Treat this as a temporary error. */
2393
2394 auth_defer_msg = expand_string_message;
2395 /* Fall through */
2396
2397 case DEFER:
2398 s = string_sprintf("435 Unable to authenticate at present%s",
2399 auth_defer_user_msg);
2400 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2401 set_id, auth_defer_msg);
2402 break;
2403
2404 case BAD64:
2405 s = ss = US"501 Invalid base64 data";
2406 break;
2407
2408 case CANCELLED:
2409 s = ss = US"501 Authentication cancelled";
2410 break;
2411
2412 case UNEXPECTED:
2413 s = ss = US"553 Initial data not expected";
2414 break;
2415
2416 case FAIL:
2417 s = US"535 Incorrect authentication data";
2418 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2419 break;
2420
2421 default:
2422 s = US"435 Internal error";
2423 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2424 "check", set_id, c);
2425 break;
2426 }
2427
2428 smtp_printf("%s\r\n", s);
2429 if (c != OK)
2430 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2431 au->name, host_and_ident(FALSE), ss);
2432
2433 break; /* AUTH_CMD */
2434
2435 /* The HELO/EHLO commands are permitted to appear in the middle of a
2436 session as well as at the beginning. They have the effect of a reset in
2437 addition to their other functions. Their absence at the start cannot be
2438 taken to be an error.
2439
2440 RFC 2821 says:
2441
2442 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2443 or 502 failure replies MUST be returned as appropriate. The SMTP
2444 server MUST stay in the same state after transmitting these replies
2445 that it was in before the EHLO was received.
2446
2447 Therefore, we do not do the reset until after checking the command for
2448 acceptability. This change was made for Exim release 4.11. Previously
2449 it did the reset first. */
2450
2451 case HELO_CMD:
2452 hello = US"HELO";
2453 esmtp = FALSE;
2454 goto HELO_EHLO;
2455
2456 case EHLO_CMD:
2457 hello = US"EHLO";
2458 esmtp = TRUE;
2459
2460 HELO_EHLO: /* Common code for HELO and EHLO */
2461 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2462 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2463
2464 /* Reject the HELO if its argument was invalid or non-existent. A
2465 successful check causes the argument to be saved in malloc store. */
2466
3ee512ff 2467 if (!check_helo(smtp_cmd_argument))
059ec3d9
PH
2468 {
2469 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2470
2471 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2472 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3ee512ff
PH
2473 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2474 string_printing(smtp_cmd_argument));
059ec3d9
PH
2475
2476 if (++synprot_error_count > smtp_max_synprot_errors)
2477 {
2478 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2479 "syntax or protocol errors (last command was \"%s\")",
3ee512ff 2480 host_and_ident(FALSE), smtp_cmd_buffer);
059ec3d9
PH
2481 done = 1;
2482 }
2483
2484 break;
2485 }
2486
2487 /* If sender_host_unknown is true, we have got here via the -bs interface,
2488 not called from inetd. Otherwise, we are running an IP connection and the
2489 host address will be set. If the helo name is the primary name of this
2490 host and we haven't done a reverse lookup, force one now. If helo_required
2491 is set, ensure that the HELO name matches the actual host. If helo_verify
2492 is set, do the same check, but softly. */
2493
2494 if (!sender_host_unknown)
2495 {
2496 BOOL old_helo_verified = helo_verified;
3ee512ff 2497 uschar *p = smtp_cmd_argument;
059ec3d9
PH
2498
2499 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2500 *p = 0;
2501
2502 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2503 because otherwise the log can be confusing. */
2504
2505 if (sender_host_name == NULL &&
2506 (deliver_domain = sender_helo_name, /* set $domain */
2507 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2508 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2509 (void)host_name_lookup();
2510
2511 /* Rebuild the fullhost info to include the HELO name (and the real name
2512 if it was looked up.) */
2513
2514 host_build_sender_fullhost(); /* Rebuild */
2515 set_process_info("handling%s incoming connection from %s",
2516 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2517
2518 /* Verify if configured. This doesn't give much security, but it does
d7b47fd0
PH
2519 make some people happy to be able to do it. If helo_required is set,
2520 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2521 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2522 now obsolescent, since the verification can now be requested selectively
2523 at ACL time. */
059ec3d9 2524
d7b47fd0 2525 helo_verified = helo_verify_failed = FALSE;
059ec3d9
PH
2526 if (helo_required || helo_verify)
2527 {
d7b47fd0 2528 BOOL tempfail = !smtp_verify_helo();
059ec3d9
PH
2529 if (!helo_verified)
2530 {
2531 if (helo_required)
2532 {
2533 smtp_printf("%d %s argument does not match calling host\r\n",
2534 tempfail? 451 : 550, hello);
2535 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2536 tempfail? "temporarily " : "",
2537 hello, sender_helo_name, host_and_ident(FALSE));
2538 helo_verified = old_helo_verified;
2539 break; /* End of HELO/EHLO processing */
2540 }
2541 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2542 "helo_try_verify_hosts\n", hello);
2543 }
2544 }
2545 }
2546
8523533c
TK
2547#ifdef EXPERIMENTAL_SPF
2548 /* set up SPF context */
2549 spf_init(sender_helo_name, sender_host_address);
2550#endif
2551
059ec3d9
PH
2552 /* Apply an ACL check if one is defined */
2553
2554 if (acl_smtp_helo != NULL)
2555 {
64ffc24f 2556 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
059ec3d9
PH
2557 if (rc != OK)
2558 {
2559 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2560 sender_helo_name = NULL;
2561 host_build_sender_fullhost(); /* Rebuild */
2562 break;
2563 }
2564 }
2565
2566 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2567 abandoning any previous message. */
2568
2569 received_protocol = (esmtp?
2570 protocols[pextend +
2571 ((sender_host_authenticated != NULL)? pauthed : 0) +
2572 ((tls_active >= 0)? pcrpted : 0)]
2573 :
981756db 2574 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
059ec3d9
PH
2575 +
2576 ((sender_host_address != NULL)? pnlocal : 0);
2577
2578 smtp_reset(reset_point);
2579 toomany = FALSE;
2580
2581 /* Generate an OK reply, including the ident if present, and also
2582 the IP address if present. Reflecting back the ident is intended
2583 as a deterrent to mail forgers. For maximum efficiency, and also
2584 because some broken systems expect each response to be in a single
2585 packet, arrange that it is sent in one write(). */
2586
2587 auth_advertised = FALSE;
2588 pipelining_advertised = FALSE;
2589 #ifdef SUPPORT_TLS
2590 tls_advertised = FALSE;
2591 #endif
2592
2593 s = string_sprintf("250 %s Hello %s%s%s",
2594 smtp_active_hostname,
2595 (sender_ident == NULL)? US"" : sender_ident,
2596 (sender_ident == NULL)? US"" : US" at ",
2597 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2598
2599 ptr = Ustrlen(s);
2600 size = ptr + 1;
2601
2602 if (sender_host_address != NULL)
2603 {
2604 s = string_cat(s, &size, &ptr, US" [", 2);
2605 s = string_cat(s, &size, &ptr, sender_host_address,
2606 Ustrlen(sender_host_address));
2607 s = string_cat(s, &size, &ptr, US"]", 1);
2608 }
2609
2610 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2611
2612 /* If we received EHLO, we must create a multiline response which includes
2613 the functions supported. */
2614
2615 if (esmtp)
2616 {
2617 s[3] = '-';
2618
2619 /* I'm not entirely happy with this, as an MTA is supposed to check
2620 that it has enough room to accept a message of maximum size before
2621 it sends this. However, there seems little point in not sending it.
2622 The actual size check happens later at MAIL FROM time. By postponing it
2623 till then, VRFY and EXPN can be used after EHLO when space is short. */
2624
2625 if (thismessage_size_limit > 0)
2626 {
2627 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2628 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2629 }
2630 else
2631 {
2632 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2633 }
2634
2635 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2636 clean; if it has an 8-bit character in its hand, it just sends it. It
2637 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2638 However, some users want this option simply in order to stop MUAs
2639 mangling messages that contain top-bit-set characters. It is therefore
2640 provided as an option. */
2641
2642 if (accept_8bitmime)
2643 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2644
2645 /* Advertise ETRN if there's an ACL checking whether a host is
2646 permitted to issue it; a check is made when any host actually tries. */
2647
2648 if (acl_smtp_etrn != NULL)
2649 {
2650 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2651 }
2652
2653 /* Advertise EXPN if there's an ACL checking whether a host is
2654 permitted to issue it; a check is made when any host actually tries. */
2655
2656 if (acl_smtp_expn != NULL)
2657 {
2658 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2659 }
2660
2661 /* Exim is quite happy with pipelining, so let the other end know that
2662 it is safe to use it, unless advertising is disabled. */
2663
2664 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2665 {
2666 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2667 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2668 pipelining_advertised = TRUE;
2669 }
2670
2671 /* If any server authentication mechanisms are configured, advertise
2672 them if the current host is in auth_advertise_hosts. The problem with
2673 advertising always is that some clients then require users to
2674 authenticate (and aren't configurable otherwise) even though it may not
2675 be necessary (e.g. if the host is in host_accept_relay).
2676
2677 RFC 2222 states that SASL mechanism names contain only upper case
2678 letters, so output the names in upper case, though we actually recognize
2679 them in either case in the AUTH command. */
2680
2681 if (auths != NULL)
2682 {
2683 if (verify_check_host(&auth_advertise_hosts) == OK)
2684 {
2685 auth_instance *au;
2686 BOOL first = TRUE;
2687 for (au = auths; au != NULL; au = au->next)
2688 {
2689 if (au->server && (au->advertise_condition == NULL ||
2690 expand_check_condition(au->advertise_condition, au->name,
2691 US"authenticator")))
2692 {
2693 int saveptr;
2694 if (first)
2695 {
2696 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2697 first = FALSE;
2698 auth_advertised = TRUE;
2699 }
2700 saveptr = ptr;
2701 s = string_cat(s, &size, &ptr, US" ", 1);
2702 s = string_cat(s, &size, &ptr, au->public_name,
2703 Ustrlen(au->public_name));
2704 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2705 au->advertised = TRUE;
2706 }
2707 else au->advertised = FALSE;
2708 }
2709 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2710 }
2711 }
2712
2713 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2714 if it has been included in the binary, and the host matches
2715 tls_advertise_hosts. We must *not* advertise if we are already in a
2716 secure connection. */
2717
2718 #ifdef SUPPORT_TLS
2719 if (tls_active < 0 &&
2720 verify_check_host(&tls_advertise_hosts) != FAIL)
2721 {
2722 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2723 tls_advertised = TRUE;
2724 }
2725 #endif
2726
2727 /* Finish off the multiline reply with one that is always available. */
2728
2729 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2730 }
2731
2732 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2733 has been seen. */
2734
2735 s[ptr] = 0;
2736
2737 #ifdef SUPPORT_TLS
2738 if (tls_active >= 0) (void)tls_write(s, ptr); else
2739 #endif
2740
f1e894f3 2741 (void)fwrite(s, 1, ptr, smtp_out);
898d150f
PH
2742 DEBUG(D_receive)
2743 {
2744 uschar *cr;
2745 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
2746 memmove(cr, cr + 1, (ptr--) - (cr - s));
2747 debug_printf("SMTP>> %s", s);
2748 }
059ec3d9
PH
2749 helo_seen = TRUE;
2750 break; /* HELO/EHLO */
2751
2752
2753 /* The MAIL command requires an address as an operand. All we do
2754 here is to parse it for syntactic correctness. The form "<>" is
2755 a special case which converts into an empty string. The start/end
2756 pointers in the original are not used further for this address, as
2757 it is the canonical extracted address which is all that is kept. */
2758
2759 case MAIL_CMD:
2760 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2761 was_rej_mail = TRUE; /* Reset if accepted */
2762
2763 if (helo_required && !helo_seen)
2764 {
2765 smtp_printf("503 HELO or EHLO required\r\n");
2766 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2767 "HELO/EHLO given", host_and_ident(FALSE));
2768 break;
2769 }
2770
2771 if (sender_address != NULL)
2772 {
2773 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2774 US"sender already given");
2775 break;
2776 }
2777
3ee512ff 2778 if (smtp_cmd_argument[0] == 0)
059ec3d9
PH
2779 {
2780 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2781 US"MAIL must have an address operand");
2782 break;
2783 }
2784
2785 /* Check to see if the limit for messages per connection would be
2786 exceeded by accepting further messages. */
2787
2788 if (smtp_accept_max_per_connection > 0 &&
2789 smtp_mailcmd_count > smtp_accept_max_per_connection)
2790 {
2791 smtp_printf("421 too many messages in this connection\r\n");
2792 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2793 "messages in one connection", host_and_ident(TRUE));
2794 break;
2795 }
2796
2797 /* Reset for start of message - even if this is going to fail, we
2798 obviously need to throw away any previous data. */
2799
2800 smtp_reset(reset_point);
2801 toomany = FALSE;
2802 sender_data = recipient_data = NULL;
2803
2804 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2805
2806 if (esmtp) for(;;)
2807 {
2808 uschar *name, *value, *end;
2809 unsigned long int size;
2810
2811 if (!extract_option(&name, &value)) break;
2812
2813 /* Handle SIZE= by reading the value. We don't do the check till later,
2814 in order to be able to log the sender address on failure. */
2815
2816 if (strcmpic(name, US"SIZE") == 0 &&
2817 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2818 {
2819 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2820 size = INT_MAX;
2821 message_size = (int)size;
2822 }
2823
2824 /* If this session was initiated with EHLO and accept_8bitmime is set,
2825 Exim will have indicated that it supports the BODY=8BITMIME option. In
2826 fact, it does not support this according to the RFCs, in that it does not
2827 take any special action for forwarding messages containing 8-bit
2828 characters. That is why accept_8bitmime is not the default setting, but
2829 some sites want the action that is provided. We recognize both "8BITMIME"
2830 and "7BIT" as body types, but take no action. */
2831
2832 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2833 (strcmpic(value, US"8BITMIME") == 0 ||
2834 strcmpic(value, US"7BIT") == 0)) {}
2835
2836 /* Handle the AUTH extension. If the value given is not "<>" and either
2837 the ACL says "yes" or there is no ACL but the sending host is
2838 authenticated, we set it up as the authenticated sender. However, if the
2839 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2840 the condition is met. The value of AUTH is an xtext, which means that +,
2841 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2842 coding. */
2843
2844 else if (strcmpic(name, US"AUTH") == 0)
2845 {
2846 if (Ustrcmp(value, "<>") != 0)
2847 {
2848 int rc;
2849 uschar *ignore_msg;
2850
2851 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2852 {
2853 /* Put back terminator overrides for error message */
2854 name[-1] = ' ';
2855 value[-1] = '=';
2856 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2857 US"invalid data for AUTH");
2858 goto COMMAND_LOOP;
2859 }
2860
2861 if (acl_smtp_mailauth == NULL)
2862 {
2863 ignore_msg = US"client not authenticated";
2864 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2865 }
2866 else
2867 {
2868 ignore_msg = US"rejected by ACL";
2869 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2870 &user_msg, &log_msg);
2871 }
2872
2873 switch (rc)
2874 {
2875 case OK:
2876 if (authenticated_by == NULL ||
2877 authenticated_by->mail_auth_condition == NULL ||
2878 expand_check_condition(authenticated_by->mail_auth_condition,
2879 authenticated_by->name, US"authenticator"))
2880 break; /* Accept the AUTH */
2881
2882 ignore_msg = US"server_mail_auth_condition failed";
2883 if (authenticated_id != NULL)
2884 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2885 ignore_msg, authenticated_id);
2886
2887 /* Fall through */
2888
2889 case FAIL:
2890 authenticated_sender = NULL;
2891 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2892 value, host_and_ident(TRUE), ignore_msg);
2893 break;
2894
2895 /* Should only get DEFER or ERROR here. Put back terminator
2896 overrides for error message */
2897
2898 default:
2899 name[-1] = ' ';
2900 value[-1] = '=';
2901 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2902 log_msg);
2903 goto COMMAND_LOOP;
2904 }
2905 }
2906 }
2907
2908 /* Unknown option. Stick back the terminator characters and break
2909 the loop. An error for a malformed address will occur. */
2910
2911 else
2912 {
2913 name[-1] = ' ';
2914 value[-1] = '=';
2915 break;
2916 }
2917 }
2918
2919 /* If we have passed the threshold for rate limiting, apply the current
2920 delay, and update it for next time, provided this is a limited host. */
2921
2922 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2923 verify_check_host(&smtp_ratelimit_hosts) == OK)
2924 {
2925 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2926 smtp_delay_mail/1000.0);
2927 millisleep((int)smtp_delay_mail);
2928 smtp_delay_mail *= smtp_rlm_factor;
2929 if (smtp_delay_mail > (double)smtp_rlm_limit)
2930 smtp_delay_mail = (double)smtp_rlm_limit;
2931 }
2932
2933 /* Now extract the address, first applying any SMTP-time rewriting. The
2934 TRUE flag allows "<>" as a sender address. */
2935
2936 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3ee512ff
PH
2937 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
2938 global_rewrite_rules) : smtp_cmd_argument;
059ec3d9
PH
2939
2940 /* rfc821_domains = TRUE; << no longer needed */
2941 raw_sender =
2942 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2943 TRUE);
2944 /* rfc821_domains = FALSE; << no longer needed */
2945
2946 if (raw_sender == NULL)
2947 {
3ee512ff 2948 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
059ec3d9
PH
2949 break;
2950 }
2951
2952 sender_address = raw_sender;
2953
2954 /* If there is a configured size limit for mail, check that this message
2955 doesn't exceed it. The check is postponed to this point so that the sender
2956 can be logged. */
2957
2958 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2959 {
2960 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2961 log_write(L_size_reject,
2962 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2963 "message too big: size%s=%d max=%d",
2964 sender_address,
2965 host_and_ident(TRUE),
2966 (message_size == INT_MAX)? ">" : "",
2967 message_size,
2968 thismessage_size_limit);
2969 sender_address = NULL;
2970 break;
2971 }
2972
2973 /* Check there is enough space on the disk unless configured not to.
2974 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2975 plus the current message - i.e. we accept the message only if it won't
2976 reduce the space below the threshold. Add 5000 to the size to allow for
2977 overheads such as the Received: line and storing of recipients, etc.
2978 By putting the check here, even when SIZE is not given, it allow VRFY
2979 and EXPN etc. to be used when space is short. */
2980
2981 if (!receive_check_fs(
2982 (smtp_check_spool_space && message_size >= 0)?
2983 message_size + 5000 : 0))
2984 {
2985 smtp_printf("452 Space shortage, please try later\r\n");
2986 sender_address = NULL;
2987 break;
2988 }
2989
2990 /* If sender_address is unqualified, reject it, unless this is a locally
2991 generated message, or the sending host or net is permitted to send
2992 unqualified addresses - typically local machines behaving as MUAs -
2993 in which case just qualify the address. The flag is set above at the start
2994 of the SMTP connection. */
2995
2996 if (sender_domain == 0 && sender_address[0] != 0)
2997 {
2998 if (allow_unqualified_sender)
2999 {
3000 sender_domain = Ustrlen(sender_address) + 1;
3001 sender_address = rewrite_address_qualify(sender_address, FALSE);
3002 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3003 raw_sender);
3004 }
3005 else
3006 {
3007 smtp_printf("501 %s: sender address must contain a domain\r\n",
3ee512ff 3008 smtp_cmd_argument);
059ec3d9
PH
3009 log_write(L_smtp_syntax_error,
3010 LOG_MAIN|LOG_REJECT,
3011 "unqualified sender rejected: <%s> %s%s",
3012 raw_sender,
3013 host_and_ident(TRUE),
3014 host_lookup_msg);
3015 sender_address = NULL;
3016 break;
3017 }
3018 }
3019
3020 /* Apply an ACL check if one is defined, before responding */
3021
3022 rc = (acl_smtp_mail == NULL)? OK :
3023 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3024
3025 if (rc == OK || rc == DISCARD)
3026 {
3027 smtp_printf("250 OK\r\n");
3028 smtp_delay_rcpt = smtp_rlr_base;
3029 recipients_discarded = (rc == DISCARD);
3030 was_rej_mail = FALSE;
3031 }
3032
3033 else
3034 {
3035 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3036 sender_address = NULL;
3037 }
3038 break;
3039
3040
3041 /* The RCPT command requires an address as an operand. All we do
3042 here is to parse it for syntactic correctness. There may be any number
3043 of RCPT commands, specifying multiple senders. We build them all into
3044 a data structure that is in argc/argv format. The start/end values
3045 given by parse_extract_address are not used, as we keep only the
3046 extracted address. */
3047
3048 case RCPT_CMD:
3049 rcpt_count++;
3050 was_rcpt = TRUE;
3051
3052 /* There must be a sender address; if the sender was rejected and
3053 pipelining was advertised, we assume the client was pipelining, and do not
3054 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3055 get the same treatment. */
3056
3057 if (sender_address == NULL)
3058 {
3059 if (pipelining_advertised && last_was_rej_mail)
3060 {
3061 smtp_printf("503 sender not yet given\r\n");
3062 was_rej_mail = TRUE;
3063 }
3064 else
3065 {
3066 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3067 US"sender not yet given");
3068 was_rcpt = FALSE; /* Not a valid RCPT */
3069 }
3070 rcpt_fail_count++;
3071 break;
3072 }
3073
3074 /* Check for an operand */
3075
3ee512ff 3076 if (smtp_cmd_argument[0] == 0)
059ec3d9
PH
3077 {
3078 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3079 US"RCPT must have an address operand");
3080 rcpt_fail_count++;
3081 break;
3082 }
3083
3084 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3085 as a recipient address */
3086
3087 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3ee512ff
PH
3088 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
3089 global_rewrite_rules) : smtp_cmd_argument;
059ec3d9
PH
3090
3091 /* rfc821_domains = TRUE; << no longer needed */
3092 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3093 &recipient_domain, FALSE);
3094 /* rfc821_domains = FALSE; << no longer needed */
3095
3096 if (recipient == NULL)
3097 {
3ee512ff 3098 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
059ec3d9
PH
3099 rcpt_fail_count++;
3100 break;
3101 }
3102
3103 /* If the recipient address is unqualified, reject it, unless this is a
3104 locally generated message. However, unqualified addresses are permitted
3105 from a configured list of hosts and nets - typically when behaving as
3106 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3107 really. The flag is set at the start of the SMTP connection.
3108
3109 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3110 assumed this meant "reserved local part", but the revision of RFC 821 and
3111 friends now makes it absolutely clear that it means *mailbox*. Consequently
3112 we must always qualify this address, regardless. */
3113
3114 if (recipient_domain == 0)
3115 {
3116 if (allow_unqualified_recipient ||
3117 strcmpic(recipient, US"postmaster") == 0)
3118 {
3119 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3120 recipient);
3121 recipient_domain = Ustrlen(recipient) + 1;
3122 recipient = rewrite_address_qualify(recipient, TRUE);
3123 }
3124 else
3125 {
3126 rcpt_fail_count++;
3127 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3ee512ff 3128 smtp_cmd_argument);
059ec3d9
PH
3129 log_write(L_smtp_syntax_error,
3130 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3131 "<%s> %s%s", recipient, host_and_ident(TRUE),
3132 host_lookup_msg);
3133 break;
3134 }
3135 }
3136
3137 /* Check maximum allowed */
3138
3139 if (rcpt_count > recipients_max && recipients_max > 0)
3140 {
3141 if (recipients_max_reject)
3142 {
3143 rcpt_fail_count++;
3144 smtp_printf("552 too many recipients\r\n");
3145 if (!toomany)
3146 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3147 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3148 }
3149 else
3150 {
3151 rcpt_defer_count++;
3152 smtp_printf("452 too many recipients\r\n");
3153 if (!toomany)
3154 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3155 "temporarily rejected: sender=<%s> %s", sender_address,
3156 host_and_ident(TRUE));
3157 }
3158
3159 toomany = TRUE;
3160 break;
3161 }
3162
3163 /* If we have passed the threshold for rate limiting, apply the current
3164 delay, and update it for next time, provided this is a limited host. */
3165
3166 if (rcpt_count > smtp_rlr_threshold &&
3167 verify_check_host(&smtp_ratelimit_hosts) == OK)
3168 {
3169 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3170 smtp_delay_rcpt/1000.0);
3171 millisleep((int)smtp_delay_rcpt);
3172 smtp_delay_rcpt *= smtp_rlr_factor;
3173 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3174 smtp_delay_rcpt = (double)smtp_rlr_limit;
3175 }
3176
3177 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3178 for them. Otherwise, check the access control list for this recipient. */
3179
3180 rc = recipients_discarded? DISCARD :
3181 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3182
3183 /* The ACL was happy */
3184
3185 if (rc == OK)
3186 {
3187 smtp_printf("250 Accepted\r\n");
3188 receive_add_recipient(recipient, -1);
3189 }
3190
3191 /* The recipient was discarded */
3192
3193 else if (rc == DISCARD)
3194 {
3195 smtp_printf("250 Accepted\r\n");
3196 rcpt_fail_count++;
3197 discarded = TRUE;
3198 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3199 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3200 (sender_address_unrewritten != NULL)?
3201 sender_address_unrewritten : sender_address,
3ee512ff 3202 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
059ec3d9
PH
3203 (log_msg == NULL)? US"" : US": ",
3204 (log_msg == NULL)? US"" : log_msg);
3205 }
3206
3207 /* Either the ACL failed the address, or it was deferred. */
3208
3209 else
3210 {
3211 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3212 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3213 }
3214 break;
3215
3216
3217 /* The DATA command is legal only if it follows successful MAIL FROM
3218 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3219 not counted as a protocol error if it follows RCPT (which must have been
3220 rejected if there are no recipients.) This function is complete when a
3221 valid DATA command is encountered.
3222
3223 Note concerning the code used: RFC 2821 says this:
3224
3225 - If there was no MAIL, or no RCPT, command, or all such commands
3226 were rejected, the server MAY return a "command out of sequence"
3227 (503) or "no valid recipients" (554) reply in response to the
3228 DATA command.
3229
3230 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3231 because it is the same whether pipelining is in use or not. */
3232
3233 case DATA_CMD:
3234 if (!discarded && recipients_count <= 0)
3235 {
3236 if (pipelining_advertised && last_was_rcpt)
3237 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3238 else
3239 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3240 US"valid RCPT command must precede DATA");
3241 break;
3242 }
3243
3244 if (toomany && recipients_max_reject)
3245 {
3246 sender_address = NULL; /* This will allow a new MAIL without RSET */
3247 sender_address_unrewritten = NULL;
3248 smtp_printf("554 Too many recipients\r\n");
3249 break;
3250 }
8e669ac1 3251
5be20824 3252 if (acl_smtp_predata == NULL) rc = OK; else
8e669ac1 3253 {
5be20824 3254 enable_dollar_recipients = TRUE;
8e669ac1 3255 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
5be20824
PH
3256 &log_msg);
3257 enable_dollar_recipients = FALSE;
3258 }
059ec3d9
PH
3259
3260 if (rc == OK)
3261 {
3262 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3263 done = 3;
3264 message_ended = END_NOTENDED; /* Indicate in middle of data */
3265 }
3266
3267 /* Either the ACL failed the address, or it was deferred. */
3268
3269 else
3270 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3271
3272 break;
3273
3274
3275 case VRFY_CMD:
64ffc24f 3276 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
059ec3d9
PH
3277 if (rc != OK)
3278 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3279 else
3280 {
3281 uschar *address;
3282 uschar *s = NULL;
3283
3284 /* rfc821_domains = TRUE; << no longer needed */
3ee512ff 3285 address = parse_extract_address(smtp_cmd_argument, &errmess, &start, &end,
059ec3d9
PH
3286 &recipient_domain, FALSE);
3287 /* rfc821_domains = FALSE; << no longer needed */
3288
3289 if (address == NULL)
3290 s = string_sprintf("501 %s", errmess);
3291 else
3292 {
3293 address_item *addr = deliver_make_addr(address, FALSE);
3294 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
4deaf07d 3295 -1, -1, NULL, NULL, NULL))
059ec3d9
PH
3296 {
3297 case OK:
3298 s = string_sprintf("250 <%s> is deliverable", address);
3299 break;
3300
3301 case DEFER:
81e509d7
PH
3302 s = (addr->user_message != NULL)?
3303 string_sprintf("451 <%s> %s", address, addr->user_message) :
059ec3d9
PH
3304 string_sprintf("451 Cannot resolve <%s> at this time", address);
3305 break;
3306
3307 case FAIL:
81e509d7
PH
3308 s = (addr->user_message != NULL)?
3309 string_sprintf("550 <%s> %s", address, addr->user_message) :
059ec3d9
PH
3310 string_sprintf("550 <%s> is not deliverable", address);
3311 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3ee512ff 3312 smtp_cmd_argument, host_and_ident(TRUE));
059ec3d9
PH
3313 break;
3314 }
3315 }
3316
3317 smtp_printf("%s\r\n", s);
3318 }
3319 break;
3320
3321
3322 case EXPN_CMD:
64ffc24f 3323 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
059ec3d9
PH
3324 if (rc != OK)
3325 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3326 else
3327 {
3328 BOOL save_log_testing_mode = log_testing_mode;
3329 address_test_mode = log_testing_mode = TRUE;
3ee512ff 3330 (void) verify_address(deliver_make_addr(smtp_cmd_argument, FALSE),
64ffc24f
PH
3331 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3332 NULL, NULL, NULL);
059ec3d9
PH
3333 address_test_mode = FALSE;
3334 log_testing_mode = save_log_testing_mode; /* true for -bh */
3335 }
3336 break;
3337
3338
3339 #ifdef SUPPORT_TLS
3340
3341 case STARTTLS_CMD:
3342 if (!tls_advertised)
3343 {
3344 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3345 US"STARTTLS command used when not advertised");
3346 break;
3347 }
3348
3349 /* Apply an ACL check if one is defined */
3350
3351 if (acl_smtp_starttls != NULL)
3352 {
3353 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3354 &log_msg);
3355 if (rc != OK)
3356 {
3357 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3358 break;
3359 }
3360 }
3361
3362 /* RFC 2487 is not clear on when this command may be sent, though it
3363 does state that all information previously obtained from the client
3364 must be discarded if a TLS session is started. It seems reasonble to
3365 do an implied RSET when STARTTLS is received. */
3366
3367 incomplete_transaction_log(US"STARTTLS");
3368 smtp_reset(reset_point);
3369 toomany = FALSE;
3370 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3371
3372 /* Attempt to start up a TLS session, and if successful, discard all
3373 knowledge that was obtained previously. At least, that's what the RFC says,
3374 and that's what happens by default. However, in order to work round YAEB,
3375 there is an option to remember the esmtp state. Sigh.
3376
3377 We must allow for an extra EHLO command and an extra AUTH command after
3378 STARTTLS that don't add to the nonmail command count. */
3379
3380 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3381 {
3382 if (!tls_remember_esmtp)
3383 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3384 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3385 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3386 if (sender_helo_name != NULL)
3387 {
3388 store_free(sender_helo_name);
3389 sender_helo_name = NULL;
3390 host_build_sender_fullhost(); /* Rebuild */
3391 set_process_info("handling incoming TLS connection from %s",
3392 host_and_ident(FALSE));
3393 }
3394 received_protocol = (esmtp?
3395 protocols[pextend + pcrpted +
3396 ((sender_host_authenticated != NULL)? pauthed : 0)]
3397 :
981756db 3398 protocols[pnormal + pcrpted])
059ec3d9
PH
3399 +
3400 ((sender_host_address != NULL)? pnlocal : 0);
3401
3402 sender_host_authenticated = NULL;
3403 authenticated_id = NULL;
3404 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3405 DEBUG(D_tls) debug_printf("TLS active\n");
3406 break; /* Successful STARTTLS */
3407 }
3408
3409 /* Some local configuration problem was discovered before actually trying
3410 to do a TLS handshake; give a temporary error. */
3411
3412 else if (rc == DEFER)
3413 {
3414 smtp_printf("454 TLS currently unavailable\r\n");
3415 break;
3416 }
3417
3418 /* Hard failure. Reject everything except QUIT or closed connection. One
3419 cause for failure is a nested STARTTLS, in which case tls_active remains
3420 set, but we must still reject all incoming commands. */
3421
3422 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3423 while (done <= 0)
3424 {
3425 switch(smtp_read_command(FALSE))
3426 {
3427 case EOF_CMD:
3428 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3429 smtp_get_connection_info());
3430 done = 2;
3431 break;
3432
3433 case QUIT_CMD:
3434 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3435 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3436 smtp_get_connection_info());
3437 done = 2;
3438 break;
3439
3440 default:
3441 smtp_printf("554 Security failure\r\n");
3442 break;
3443 }
3444 }
3445 tls_close(TRUE);
3446 break;
3447 #endif
3448
3449
3450 /* The ACL for QUIT is provided for gathering statistical information or
3451 similar; it does not affect the response code, but it can supply a custom
3452 message. */
3453
3454 case QUIT_CMD:
3455 incomplete_transaction_log(US"QUIT");
3456
3457 if (acl_smtp_quit != NULL)
3458 {
64ffc24f 3459 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit,&user_msg,&log_msg);
059ec3d9
PH
3460 if (rc == ERROR)
3461 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3462 log_msg);
3463 }
3464 else user_msg = NULL;
3465
3466 if (user_msg == NULL)
3467 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3468 else
3469 smtp_printf("221 %s\r\n", user_msg);
3470
3471 #ifdef SUPPORT_TLS
3472 tls_close(TRUE);
3473 #endif
3474
3475 done = 2;
3476 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3477 smtp_get_connection_info());
3478 break;
3479
3480
3481 case RSET_CMD:
3482 incomplete_transaction_log(US"RSET");
3483 smtp_reset(reset_point);
3484 toomany = FALSE;
3485 smtp_printf("250 Reset OK\r\n");
3486 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3487 break;
3488
3489
3490 case NOOP_CMD:
3491 smtp_printf("250 OK\r\n");
3492 break;
3493
3494
3495 /* Show ETRN/EXPN/VRFY if there's
3496 an ACL for checking hosts; if actually used, a check will be done for
3497 permitted hosts. */
3498
3499 case HELP_CMD:
3500 smtp_printf("214-Commands supported:\r\n");
3501 {
3502 uschar buffer[256];
3503 buffer[0] = 0;
3504 Ustrcat(buffer, " AUTH");
3505 #ifdef SUPPORT_TLS
3506 Ustrcat(buffer, " STARTTLS");
3507 #endif
3508 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3509 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3510 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3511 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3512 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3513 smtp_printf("214%s\r\n", buffer);
3514 }
3515 break;
3516
3517
3518 case EOF_CMD:
3519 incomplete_transaction_log(US"connection lost");
3520 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3521
3522 /* Don't log by default unless in the middle of a message, as some mailers
3523 just drop the call rather than sending QUIT, and it clutters up the logs.
3524 */
3525
3526 if (sender_address != NULL || recipients_count > 0)
3527 log_write(L_lost_incoming_connection,
3528 LOG_MAIN,
3529 "unexpected %s while reading SMTP command from %s%s",
3530 sender_host_unknown? "EOF" : "disconnection",
3531 host_and_ident(FALSE), smtp_read_error);
3532
3533 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3534 smtp_get_connection_info(), smtp_read_error);
3535
3536 done = 1;
3537 break;
3538
3539
3540 case ETRN_CMD:
3541 if (sender_address != NULL)
3542 {
3543 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3544 US"ETRN is not permitted inside a transaction");
3545 break;
3546 }
3547
3ee512ff 3548 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
059ec3d9
PH
3549 host_and_ident(FALSE));
3550
64ffc24f 3551 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
059ec3d9
PH
3552 if (rc != OK)
3553 {
3554 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3555 break;
3556 }
3557
3558 /* Compute the serialization key for this command. */
3559
3ee512ff 3560 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_argument);
059ec3d9
PH
3561
3562 /* If a command has been specified for running as a result of ETRN, we
3563 permit any argument to ETRN. If not, only the # standard form is permitted,
3564 since that is strictly the only kind of ETRN that can be implemented
3565 according to the RFC. */
3566
3567 if (smtp_etrn_command != NULL)
3568 {
3569 uschar *error;
3570 BOOL rc;
3571 etrn_command = smtp_etrn_command;
3ee512ff 3572 deliver_domain = smtp_cmd_argument;
059ec3d9
PH
3573 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3574 US"ETRN processing", &error);
3575 deliver_domain = NULL;
3576 if (!rc)
3577 {
3578 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3579 error);
3580 smtp_printf("458 Internal failure\r\n");
3581 break;
3582 }
3583 }
3584
3585 /* Else set up to call Exim with the -R option. */
3586
3587 else
3588 {
3ee512ff 3589 if (*smtp_cmd_argument++ != '#')
059ec3d9
PH
3590 {
3591 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3592 US"argument must begin with #");
3593 break;
3594 }
3595 etrn_command = US"exim -R";
3596 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3ee512ff 3597 smtp_cmd_argument);
059ec3d9
PH
3598 }
3599
3600 /* If we are host-testing, don't actually do anything. */
3601
3602 if (host_checking)
3603 {
3604 HDEBUG(D_any)
3605 {
3606 debug_printf("ETRN command is: %s\n", etrn_command);
3607 debug_printf("ETRN command execution skipped\n");
3608 }
3609 smtp_printf("250 OK\r\n");
3610 break;
3611 }
3612
3613
3614 /* If ETRN queue runs are to be serialized, check the database to
3615 ensure one isn't already running. */
3616
3617 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3618 {
3ee512ff 3619 smtp_printf("458 Already processing %s\r\n", smtp_cmd_argument);
059ec3d9
PH
3620 break;
3621 }
3622
3623 /* Fork a child process and run the command. We don't want to have to
3624 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3625 forking. It should be set that way anyway for external incoming SMTP,
3626 but we save and restore to be tidy. If serialization is required, we
3627 actually run the command in yet another process, so we can wait for it
3628 to complete and then remove the serialization lock. */
3629
3630 oldsignal = signal(SIGCHLD, SIG_IGN);
3631
3632 if ((pid = fork()) == 0)
3633 {
f1e894f3
PH
3634 smtp_input = FALSE; /* This process is not associated with the */
3635 (void)fclose(smtp_in); /* SMTP call any more. */
3636 (void)fclose(smtp_out);
059ec3d9
PH
3637
3638 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3639
3640 /* If not serializing, do the exec right away. Otherwise, fork down
3641 into another process. */
3642
3643 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3644 {
3645 DEBUG(D_exec) debug_print_argv(argv);
3646 exim_nullstd(); /* Ensure std{in,out,err} exist */
3647 execv(CS argv[0], (char *const *)argv);
3648 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3649 etrn_command, strerror(errno));
3650 _exit(EXIT_FAILURE); /* paranoia */
3651 }
3652
3653 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3654 is, we are in the first subprocess, after forking again. All we can do
3655 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3656 complete, before removing the serialization. */
3657
3658 if (pid < 0)
3659 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3660 "failed: %s", strerror(errno));
3661 else
3662 {
3663 int status;
3664 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3665 (int)pid);
3666 (void)wait(&status);
3667 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3668 (int)pid);
3669 }
3670
3671 enq_end(etrn_serialize_key);
3672 _exit(EXIT_SUCCESS);
3673 }
3674
3675 /* Back in the top level SMTP process. Check that we started a subprocess
3676 and restore the signal state. */
3677
3678 if (pid < 0)
3679 {
3680 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3681 strerror(errno));
3682 smtp_printf("458 Unable to fork process\r\n");
3683 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3684 }
3685 else smtp_printf("250 OK\r\n");
3686
3687 signal(SIGCHLD, oldsignal);
3688 break;
3689
3690
3691 case BADARG_CMD:
3692 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3693 US"unexpected argument data");
3694 break;
3695
3696
3697 /* This currently happens only for NULLs, but could be extended. */
3698
3699 case BADCHAR_CMD:
3700 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3701 US"NULL character(s) present (shown as '?')");
3702 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3703 break;
3704
3705
3706 case BADSYN_CMD:
3707 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3708 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3709 c = smtp_inend - smtp_inptr;
3710 if (c > 150) c = 150;
3711 smtp_inptr[c] = 0;
3712 incomplete_transaction_log(US"sync failure");
3af76a81 3713 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
059ec3d9
PH
3714 "(next input sent too soon: pipelining was%s advertised): "
3715 "rejected \"%s\" %s next input=\"%s\"",
3716 pipelining_advertised? "" : " not",
3ee512ff 3717 smtp_cmd_buffer, host_and_ident(TRUE),
059ec3d9
PH
3718 string_printing(smtp_inptr));
3719 smtp_printf("554 SMTP synchronization error\r\n");
3720 done = 1; /* Pretend eof - drops connection */
3721 break;
3722
3723
3724 case TOO_MANY_NONMAIL_CMD:
3725 incomplete_transaction_log(US"too many non-mail commands");
3726 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3727 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
3ee512ff 3728 smtp_cmd_argument - smtp_cmd_buffer, smtp_cmd_buffer);
059ec3d9
PH
3729 smtp_printf("554 Too many nonmail commands\r\n");
3730 done = 1; /* Pretend eof - drops connection */
3731 break;
3732
3733
3734 default:
3735 if (unknown_command_count++ >= smtp_max_unknown_commands)
3736 {
3737 log_write(L_smtp_syntax_error, LOG_MAIN,
3738 "SMTP syntax error in \"%s\" %s %s",
3ee512ff 3739 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
059ec3d9
PH
3740 US"unrecognized command");
3741 incomplete_transaction_log(US"unrecognized command");
3742 smtp_printf("500 Too many unrecognized commands\r\n");
3743 done = 2;
3744 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3745 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3ee512ff 3746 smtp_cmd_buffer);
059ec3d9
PH
3747 }
3748 else
3749 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3750 US"unrecognized command");
3751 break;
3752 }
3753
3754 /* This label is used by goto's inside loops that want to break out to
3755 the end of the command-processing loop. */
3756
3757 COMMAND_LOOP:
3758 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3759 last_was_rcpt = was_rcpt; /* protocol error handling */
3760 continue;
3761 }
3762
3763return done - 2; /* Convert yield values */
3764}
3765
3766/* End of smtp_in.c */