Added comment about verifying errors_to as a recipient, not a sender.
[exim.git] / src / src / smtp_in.c
CommitLineData
8800895a 1/* $Cambridge: exim/src/src/smtp_in.c,v 1.25 2005/09/12 10:08:54 ph10 Exp $ */
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2
3/*************************************************
4* Exim - an Internet mail transport agent *
5*************************************************/
6
c988f1f4 7/* Copyright (c) University of Cambridge 1995 - 2005 */
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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
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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
8d67ada3 42#define cmd_buffer_size 2048
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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
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122static uschar *cmd_buffer;
123
124/* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
125final fields of all except AUTH are forced TRUE at the start of a new message
126setup, to allow one of each between messages that is not counted as a nonmail
127command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
128allow a new EHLO after starting up TLS.
129
130AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
131counted. However, the flag is changed when AUTH is received, so that multiple
132failing AUTHs will eventually hit the limit. After a successful AUTH, another
133AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
134forced TRUE, to allow for the re-authentication that can happen at that point.
135
136QUIT is also "falsely" labelled as a mail command so that it doesn't up the
137count of non-mail commands and possibly provoke an error. */
138
139static smtp_cmd_list cmd_list[] = {
140 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
141 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
142 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
143 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
144 #ifdef SUPPORT_TLS
145 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
146 #endif
147
148/* If you change anything above here, also fix the definitions below. */
149
150 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
151 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
152 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
153 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
154 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
155 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
156 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
157 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
158 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
159};
160
161static smtp_cmd_list *cmd_list_end =
162 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
163
164#define CMD_LIST_RSET 0
165#define CMD_LIST_HELO 1
166#define CMD_LIST_EHLO 2
167#define CMD_LIST_AUTH 3
168#define CMD_LIST_STARTTLS 4
169
170static uschar *protocols[] = {
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171 US"local-smtp", /* HELO */
172 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
173 US"local-esmtp", /* EHLO */
174 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
175 US"local-esmtpa", /* EHLO->AUTH */
176 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
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177 };
178
179#define pnormal 0
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180#define pextend 2
181#define pcrpted 1 /* added to pextend or pnormal */
182#define pauthed 2 /* added to pextend */
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183#define pnlocal 6 /* offset to remove "local" */
184
185/* When reading SMTP from a remote host, we have to use our own versions of the
186C input-reading functions, in order to be able to flush the SMTP output only
187when about to read more data from the socket. This is the only way to get
188optimal performance when the client is using pipelining. Flushing for every
189command causes a separate packet and reply packet each time; saving all the
190responses up (when pipelining) combines them into one packet and one response.
191
192For simplicity, these functions are used for *all* SMTP input, not only when
193receiving over a socket. However, after setting up a secure socket (SSL), input
194is read via the OpenSSL library, and another set of functions is used instead
195(see tls.c).
196
197These functions are set in the receive_getc etc. variables and called with the
198same interface as the C functions. However, since there can only ever be
199one incoming SMTP call, we just use a single buffer and flags. There is no need
200to implement a complicated private FILE-like structure.*/
201
202static uschar *smtp_inbuffer;
203static uschar *smtp_inptr;
204static uschar *smtp_inend;
205static int smtp_had_eof;
206static int smtp_had_error;
207
208
209/*************************************************
210* SMTP version of getc() *
211*************************************************/
212
213/* This gets the next byte from the SMTP input buffer. If the buffer is empty,
214it flushes the output, and refills the buffer, with a timeout. The signal
215handler is set appropriately by the calling function. This function is not used
216after a connection has negotated itself into an TLS/SSL state.
217
218Arguments: none
219Returns: the next character or EOF
220*/
221
222int
223smtp_getc(void)
224{
225if (smtp_inptr >= smtp_inend)
226 {
227 int rc, save_errno;
228 fflush(smtp_out);
229 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
230 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
231 save_errno = errno;
232 alarm(0);
233 if (rc <= 0)
234 {
235 /* Must put the error text in fixed store, because this might be during
236 header reading, where it releases unused store above the header. */
237 if (rc < 0)
238 {
239 smtp_had_error = save_errno;
240 smtp_read_error = string_copy_malloc(
241 string_sprintf(" (error: %s)", strerror(save_errno)));
242 }
243 else smtp_had_eof = 1;
244 return EOF;
245 }
246 smtp_inend = smtp_inbuffer + rc;
247 smtp_inptr = smtp_inbuffer;
248 }
249return *smtp_inptr++;
250}
251
252
253
254/*************************************************
255* SMTP version of ungetc() *
256*************************************************/
257
258/* Puts a character back in the input buffer. Only ever
259called once.
260
261Arguments:
262 ch the character
263
264Returns: the character
265*/
266
267int
268smtp_ungetc(int ch)
269{
270*(--smtp_inptr) = ch;
271return ch;
272}
273
274
275
276
277/*************************************************
278* SMTP version of feof() *
279*************************************************/
280
281/* Tests for a previous EOF
282
283Arguments: none
284Returns: non-zero if the eof flag is set
285*/
286
287int
288smtp_feof(void)
289{
290return smtp_had_eof;
291}
292
293
294
295
296/*************************************************
297* SMTP version of ferror() *
298*************************************************/
299
300/* Tests for a previous read error, and returns with errno
301restored to what it was when the error was detected.
302
303Arguments: none
304Returns: non-zero if the error flag is set
305*/
306
307int
308smtp_ferror(void)
309{
310errno = smtp_had_error;
311return smtp_had_error;
312}
313
314
315
316
317/*************************************************
318* Write formatted string to SMTP channel *
319*************************************************/
320
321/* This is a separate function so that we don't have to repeat everything for
322TLS support or debugging. It is global so that the daemon and the
323authentication functions can use it. It does not return any error indication,
324because major problems such as dropped connections won't show up till an output
325flush for non-TLS connections. The smtp_fflush() function is available for
326checking that: for convenience, TLS output errors are remembered here so that
327they are also picked up later by smtp_fflush().
328
329Arguments:
330 format format string
331 ... optional arguments
332
333Returns: nothing
334*/
335
336void
337smtp_printf(char *format, ...)
338{
339va_list ap;
340
341DEBUG(D_receive)
342 {
343 va_start(ap, format);
344 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
345 debug_printf("SMTP>> %s", big_buffer);
346 }
347
348va_start(ap, format);
349
350/* If in a TLS session we have to format the string, and then write it using a
351TLS function. */
352
353#ifdef SUPPORT_TLS
354if (tls_active >= 0)
355 {
356 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
357 {
358 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
359 smtp_closedown(US"Unexpected error");
360 exim_exit(EXIT_FAILURE);
361 }
362 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
363 }
364else
365#endif
366
367/* Otherwise, just use the standard library function. */
368
369if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
370va_end(ap);
371}
372
373
374
375/*************************************************
376* Flush SMTP out and check for error *
377*************************************************/
378
379/* This function isn't currently used within Exim (it detects errors when it
380tries to read the next SMTP input), but is available for use in local_scan().
381For non-TLS connections, it flushes the output and checks for errors. For
382TLS-connections, it checks for a previously-detected TLS write error.
383
384Arguments: none
385Returns: 0 for no error; -1 after an error
386*/
387
388int
389smtp_fflush(void)
390{
391if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
392return smtp_write_error;
393}
394
395
396
397/*************************************************
398* SMTP command read timeout *
399*************************************************/
400
401/* Signal handler for timing out incoming SMTP commands. This attempts to
402finish off tidily.
403
404Argument: signal number (SIGALRM)
405Returns: nothing
406*/
407
408static void
409command_timeout_handler(int sig)
410{
411sig = sig; /* Keep picky compilers happy */
412log_write(L_lost_incoming_connection,
413 LOG_MAIN, "SMTP command timeout on%s connection from %s",
414 (tls_active >= 0)? " TLS" : "",
415 host_and_ident(FALSE));
416if (smtp_batched_input)
417 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
418smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
419 smtp_active_hostname);
420mac_smtp_fflush();
421exim_exit(EXIT_FAILURE);
422}
423
424
425
426/*************************************************
427* SIGTERM received *
428*************************************************/
429
430/* Signal handler for handling SIGTERM. Again, try to finish tidily.
431
432Argument: signal number (SIGTERM)
433Returns: nothing
434*/
435
436static void
437command_sigterm_handler(int sig)
438{
439sig = sig; /* Keep picky compilers happy */
440log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
441if (smtp_batched_input)
442 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
443smtp_printf("421 %s: Service not available - closing connection\r\n",
444 smtp_active_hostname);
445exim_exit(EXIT_FAILURE);
446}
447
448
449
450/*************************************************
451* Read one command line *
452*************************************************/
453
454/* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
455There are sites that don't do this, and in any case internal SMTP probably
456should check only for LF. Consequently, we check here for LF only. The line
457ends up with [CR]LF removed from its end. If we get an overlong line, treat as
458an unknown command. The command is read into the static cmd_buffer.
459
460The character reading routine sets up a timeout for each block actually read
461from the input (which may contain more than one command). We set up a special
462signal handler that closes down the session on a timeout. Control does not
463return when it runs.
464
465Arguments:
466 check_sync if TRUE, check synchronization rules if global option is TRUE
467
468Returns: a code identifying the command (enumerated above)
469*/
470
471static int
472smtp_read_command(BOOL check_sync)
473{
474int c;
475int ptr = 0;
476smtp_cmd_list *p;
477BOOL hadnull = FALSE;
478
479os_non_restarting_signal(SIGALRM, command_timeout_handler);
480
481while ((c = (receive_getc)()) != '\n' && c != EOF)
482 {
483 if (ptr >= cmd_buffer_size)
484 {
485 os_non_restarting_signal(SIGALRM, sigalrm_handler);
486 return OTHER_CMD;
487 }
488 if (c == 0)
489 {
490 hadnull = TRUE;
491 c = '?';
492 }
493 cmd_buffer[ptr++] = c;
494 }
495
496receive_linecount++; /* For BSMTP errors */
497os_non_restarting_signal(SIGALRM, sigalrm_handler);
498
499/* If hit end of file, return pseudo EOF command. Whether we have a
500part-line already read doesn't matter, since this is an error state. */
501
502if (c == EOF) return EOF_CMD;
503
504/* Remove any CR and white space at the end of the line, and terminate the
505string. */
506
507while (ptr > 0 && isspace(cmd_buffer[ptr-1])) ptr--;
508cmd_buffer[ptr] = 0;
509
510DEBUG(D_receive) debug_printf("SMTP<< %s\n", cmd_buffer);
511
512/* NULLs are not allowed in SMTP commands */
513
514if (hadnull) return BADCHAR_CMD;
515
516/* Scan command list and return identity, having set the data pointer
517to the start of the actual data characters. Check for SMTP synchronization
518if required. */
519
520for (p = cmd_list; p < cmd_list_end; p++)
521 {
522 if (strncmpic(cmd_buffer, US p->name, p->len) == 0)
523 {
524 if (smtp_inptr < smtp_inend && /* Outstanding input */
525 p->cmd < sync_cmd_limit && /* Command should sync */
526 check_sync && /* Local flag set */
527 smtp_enforce_sync && /* Global flag set */
528 sender_host_address != NULL && /* Not local input */
529 !sender_host_notsocket) /* Really is a socket */
530 return BADSYN_CMD;
531
532 /* Point after the command, but don't skip over leading spaces till after
533 the following test, so that if it fails, the command name can easily be
534 logged. */
535
64ffc24f 536 smtp_command_argument = cmd_buffer + p->len;
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537
538 /* Count non-mail commands from those hosts that are controlled in this
539 way. The default is all hosts. We don't waste effort checking the list
540 until we get a non-mail command, but then cache the result to save checking
541 again. If there's a DEFER while checking the host, assume it's in the list.
542
543 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
544 start of each incoming message by fiddling with the value in the table. */
545
546 if (!p->is_mail_cmd)
547 {
548 if (count_nonmail == TRUE_UNSET) count_nonmail =
549 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
550 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
551 return TOO_MANY_NONMAIL_CMD;
552 }
553
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554 /* Get the data pointer over leading spaces and return; if there is data
555 for a command that does not expect it, give the error centrally here. */
059ec3d9 556
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557 while (isspace(*smtp_command_argument)) smtp_command_argument++;
558 return (p->has_arg || *smtp_command_argument == 0)? p->cmd : BADARG_CMD;
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559 }
560 }
561
562/* Enforce synchronization for unknown commands */
563
564if (smtp_inptr < smtp_inend && /* Outstanding input */
565 check_sync && /* Local flag set */
566 smtp_enforce_sync && /* Global flag set */
567 sender_host_address != NULL && /* Not local input */
568 !sender_host_notsocket) /* Really is a socket */
569 return BADSYN_CMD;
570
571return OTHER_CMD;
572}
573
574
575
576/*************************************************
577* Forced closedown of call *
578*************************************************/
579
580/* This function is called from log.c when Exim is dying because of a serious
581disaster, and also from some other places. If an incoming non-batched SMTP
582channel is open, it swallows the rest of the incoming message if in the DATA
583phase, sends the reply string, and gives an error to all subsequent commands
584except QUIT. The existence of an SMTP call is detected by the non-NULLness of
585smtp_in.
586
587Argument: SMTP reply string to send, excluding the code
588Returns: nothing
589*/
590
591void
592smtp_closedown(uschar *message)
593{
594if (smtp_in == NULL || smtp_batched_input) return;
595receive_swallow_smtp();
596smtp_printf("421 %s\r\n", message);
597
598for (;;)
599 {
600 switch(smtp_read_command(FALSE))
601 {
602 case EOF_CMD:
603 return;
604
605 case QUIT_CMD:
606 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
607 mac_smtp_fflush();
608 return;
609
610 case RSET_CMD:
611 smtp_printf("250 Reset OK\r\n");
612 break;
613
614 default:
615 smtp_printf("421 %s\r\n", message);
616 break;
617 }
618 }
619}
620
621
622
623
624/*************************************************
625* Set up connection info for logging *
626*************************************************/
627
628/* This function is called when logging information about an SMTP connection.
629It sets up appropriate source information, depending on the type of connection.
630
631Argument: none
632Returns: a string describing the connection
633*/
634
635uschar *
636smtp_get_connection_info(void)
637{
638if (host_checking)
639 return string_sprintf("SMTP connection from %s", sender_fullhost);
640
641if (sender_host_unknown || sender_host_notsocket)
642 return string_sprintf("SMTP connection from %s", sender_ident);
643
644if (is_inetd)
645 return string_sprintf("SMTP connection from %s (via inetd)", sender_fullhost);
646
647if ((log_extra_selector & LX_incoming_interface) != 0 &&
648 interface_address != NULL)
649 return string_sprintf("SMTP connection from %s I=[%s]:%d", sender_fullhost,
650 interface_address, interface_port);
651
652return string_sprintf("SMTP connection from %s", sender_fullhost);
653}
654
655
656
657/*************************************************
658* Check HELO line and set sender_helo_name *
659*************************************************/
660
661/* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
662the domain name of the sending host, or an ip literal in square brackets. The
663arrgument is placed in sender_helo_name, which is in malloc store, because it
664must persist over multiple incoming messages. If helo_accept_junk is set, this
665host is permitted to send any old junk (needed for some broken hosts).
666Otherwise, helo_allow_chars can be used for rogue characters in general
667(typically people want to let in underscores).
668
669Argument:
670 s the data portion of the line (already past any white space)
671
672Returns: TRUE or FALSE
673*/
674
675static BOOL
676check_helo(uschar *s)
677{
678uschar *start = s;
679uschar *end = s + Ustrlen(s);
680BOOL yield = helo_accept_junk;
681
682/* Discard any previous helo name */
683
684if (sender_helo_name != NULL)
685 {
686 store_free(sender_helo_name);
687 sender_helo_name = NULL;
688 }
689
690/* Skip tests if junk is permitted. */
691
692if (!yield)
693 {
694 /* Allow the new standard form for IPv6 address literals, namely,
695 [IPv6:....], and because someone is bound to use it, allow an equivalent
696 IPv4 form. Allow plain addresses as well. */
697
698 if (*s == '[')
699 {
700 if (end[-1] == ']')
701 {
702 end[-1] = 0;
703 if (strncmpic(s, US"[IPv6:", 6) == 0)
704 yield = (string_is_ip_address(s+6, NULL) == 6);
705 else if (strncmpic(s, US"[IPv4:", 6) == 0)
706 yield = (string_is_ip_address(s+6, NULL) == 4);
707 else
708 yield = (string_is_ip_address(s+1, NULL) != 0);
709 end[-1] = ']';
710 }
711 }
712
713 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
714 that have been configured (usually underscore - sigh). */
715
716 else if (*s != 0)
717 {
718 yield = TRUE;
719 while (*s != 0)
720 {
721 if (!isalnum(*s) && *s != '.' && *s != '-' &&
722 Ustrchr(helo_allow_chars, *s) == NULL)
723 {
724 yield = FALSE;
725 break;
726 }
727 s++;
728 }
729 }
730 }
731
732/* Save argument if OK */
733
734if (yield) sender_helo_name = string_copy_malloc(start);
735return yield;
736}
737
738
739
740
741
742/*************************************************
743* Extract SMTP command option *
744*************************************************/
745
64ffc24f 746/* This function picks the next option setting off the end of smtp_command_argument. It
059ec3d9
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747is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
748things that can appear there.
749
750Arguments:
751 name point this at the name
752 value point this at the data string
753
754Returns: TRUE if found an option
755*/
756
757static BOOL
758extract_option(uschar **name, uschar **value)
759{
760uschar *n;
64ffc24f 761uschar *v = smtp_command_argument + Ustrlen(smtp_command_argument) -1;
059ec3d9
PH
762while (isspace(*v)) v--;
763v[1] = 0;
764
64ffc24f 765while (v > smtp_command_argument && *v != '=' && !isspace(*v)) v--;
059ec3d9
PH
766if (*v != '=') return FALSE;
767
768n = v;
769while(isalpha(n[-1])) n--;
770
771if (n[-1] != ' ') return FALSE;
772
773n[-1] = 0;
774*name = n;
775*v++ = 0;
776*value = v;
777return TRUE;
778}
779
780
781
782
783
784
785
786/*************************************************
787* Reset for new message *
788*************************************************/
789
790/* This function is called whenever the SMTP session is reset from
791within either of the setup functions.
792
793Argument: the stacking pool storage reset point
794Returns: nothing
795*/
796
797static void
798smtp_reset(void *reset_point)
799{
800int i;
801store_reset(reset_point);
802recipients_list = NULL;
803rcpt_count = rcpt_defer_count = rcpt_fail_count =
804 raw_recipients_count = recipients_count = recipients_list_max = 0;
2e0c1448 805message_linecount = 0;
059ec3d9
PH
806message_size = -1;
807acl_warn_headers = NULL;
808queue_only_policy = FALSE;
69358f02 809deliver_freeze = FALSE; /* Can be set by ACL */
29aba418 810fake_response = OK; /* Can be set by ACL */
6951ac6c 811#ifdef WITH_CONTENT_SCAN
8523533c
TK
812no_mbox_unspool = FALSE; /* Can be set by ACL */
813#endif
69358f02 814submission_mode = FALSE; /* Can be set by ACL */
8800895a 815suppress_local_fixups = FALSE; /* Can be set by ACL */
69358f02
PH
816active_local_from_check = local_from_check; /* Can be set by ACL */
817active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
059ec3d9 818sender_address = NULL;
2fe1a124 819submission_name = NULL; /* Can be set by ACL */
059ec3d9
PH
820raw_sender = NULL; /* After SMTP rewrite, before qualifying */
821sender_address_unrewritten = NULL; /* Set only after verify rewrite */
822sender_verified_list = NULL; /* No senders verified */
823memset(sender_address_cache, 0, sizeof(sender_address_cache));
824memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
825authenticated_sender = NULL;
8523533c
TK
826#ifdef EXPERIMENTAL_BRIGHTMAIL
827bmi_run = 0;
828bmi_verdicts = NULL;
829#endif
fb2274d4
TK
830#ifdef EXPERIMENTAL_DOMAINKEYS
831dk_do_verify = 0;
832#endif
8523533c
TK
833#ifdef EXPERIMENTAL_SPF
834spf_header_comment = NULL;
835spf_received = NULL;
8e669ac1 836spf_result = NULL;
8523533c
TK
837spf_smtp_comment = NULL;
838#endif
059ec3d9
PH
839body_linecount = body_zerocount = 0;
840
870f6ba8
TF
841sender_rate = sender_rate_limit = sender_rate_period = NULL;
842ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
843 /* Note that ratelimiters_conn persists across resets. */
844
059ec3d9
PH
845for (i = 0; i < ACL_M_MAX; i++) acl_var[ACL_C_MAX + i] = NULL;
846
847/* The message body variables use malloc store. They may be set if this is
848not the first message in an SMTP session and the previous message caused them
849to be referenced in an ACL. */
850
851if (message_body != NULL)
852 {
853 store_free(message_body);
854 message_body = NULL;
855 }
856
857if (message_body_end != NULL)
858 {
859 store_free(message_body_end);
860 message_body_end = NULL;
861 }
862
863/* Warning log messages are also saved in malloc store. They are saved to avoid
864repetition in the same message, but it seems right to repeat them for different
865messagess. */
866
867while (acl_warn_logged != NULL)
868 {
869 string_item *this = acl_warn_logged;
870 acl_warn_logged = acl_warn_logged->next;
871 store_free(this);
872 }
873}
874
875
876
877
878
879/*************************************************
880* Initialize for incoming batched SMTP message *
881*************************************************/
882
883/* This function is called from smtp_setup_msg() in the case when
884smtp_batched_input is true. This happens when -bS is used to pass a whole batch
885of messages in one file with SMTP commands between them. All errors must be
886reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
887relevant. After an error on a sender, or an invalid recipient, the remainder
888of the message is skipped. The value of received_protocol is already set.
889
890Argument: none
891Returns: > 0 message successfully started (reached DATA)
892 = 0 QUIT read or end of file reached
893 < 0 should not occur
894*/
895
896static int
897smtp_setup_batch_msg(void)
898{
899int done = 0;
900void *reset_point = store_get(0);
901
902/* Save the line count at the start of each transaction - single commands
903like HELO and RSET count as whole transactions. */
904
905bsmtp_transaction_linecount = receive_linecount;
906
907if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
908
909smtp_reset(reset_point); /* Reset for start of message */
910
911/* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
912value. The values are 2 larger than the required yield of the function. */
913
914while (done <= 0)
915 {
916 uschar *errmess;
917 uschar *recipient = NULL;
918 int start, end, sender_domain, recipient_domain;
919
920 switch(smtp_read_command(FALSE))
921 {
922 /* The HELO/EHLO commands set sender_address_helo if they have
923 valid data; otherwise they are ignored, except that they do
924 a reset of the state. */
925
926 case HELO_CMD:
927 case EHLO_CMD:
928
64ffc24f 929 check_helo(smtp_command_argument);
059ec3d9
PH
930 /* Fall through */
931
932 case RSET_CMD:
933 smtp_reset(reset_point);
934 bsmtp_transaction_linecount = receive_linecount;
935 break;
936
937
938 /* The MAIL FROM command requires an address as an operand. All we
939 do here is to parse it for syntactic correctness. The form "<>" is
940 a special case which converts into an empty string. The start/end
941 pointers in the original are not used further for this address, as
942 it is the canonical extracted address which is all that is kept. */
943
944 case MAIL_CMD:
945 if (sender_address != NULL)
946 /* The function moan_smtp_batch() does not return. */
947 moan_smtp_batch(cmd_buffer, "503 Sender already given");
948
64ffc24f 949 if (smtp_command_argument[0] == 0)
059ec3d9
PH
950 /* The function moan_smtp_batch() does not return. */
951 moan_smtp_batch(cmd_buffer, "501 MAIL FROM must have an address operand");
952
953 /* Reset to start of message */
954
955 smtp_reset(reset_point);
956
957 /* Apply SMTP rewrite */
958
959 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
64ffc24f
PH
960 rewrite_one(smtp_command_argument, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
961 US"", global_rewrite_rules) : smtp_command_argument;
059ec3d9
PH
962
963 /* Extract the address; the TRUE flag allows <> as valid */
964
965 raw_sender =
966 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
967 TRUE);
968
969 if (raw_sender == NULL)
970 /* The function moan_smtp_batch() does not return. */
971 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
972
973 sender_address = string_copy(raw_sender);
974
975 /* Qualify unqualified sender addresses if permitted to do so. */
976
977 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
978 {
979 if (allow_unqualified_sender)
980 {
981 sender_address = rewrite_address_qualify(sender_address, FALSE);
982 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
983 "and rewritten\n", raw_sender);
984 }
985 /* The function moan_smtp_batch() does not return. */
986 else moan_smtp_batch(cmd_buffer, "501 sender address must contain "
987 "a domain");
988 }
989 break;
990
991
992 /* The RCPT TO command requires an address as an operand. All we do
993 here is to parse it for syntactic correctness. There may be any number
994 of RCPT TO commands, specifying multiple senders. We build them all into
995 a data structure that is in argc/argv format. The start/end values
996 given by parse_extract_address are not used, as we keep only the
997 extracted address. */
998
999 case RCPT_CMD:
1000 if (sender_address == NULL)
1001 /* The function moan_smtp_batch() does not return. */
1002 moan_smtp_batch(cmd_buffer, "503 No sender yet given");
1003
64ffc24f 1004 if (smtp_command_argument[0] == 0)
059ec3d9
PH
1005 /* The function moan_smtp_batch() does not return. */
1006 moan_smtp_batch(cmd_buffer, "501 RCPT TO must have an address operand");
1007
1008 /* Check maximum number allowed */
1009
1010 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1011 /* The function moan_smtp_batch() does not return. */
1012 moan_smtp_batch(cmd_buffer, "%s too many recipients",
1013 recipients_max_reject? "552": "452");
1014
1015 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1016 recipient address */
1017
1018 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
64ffc24f
PH
1019 rewrite_one(smtp_command_argument, rewrite_smtp, NULL, FALSE, US"",
1020 global_rewrite_rules) : smtp_command_argument;
059ec3d9
PH
1021
1022 /* rfc821_domains = TRUE; << no longer needed */
1023 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1024 &recipient_domain, FALSE);
1025 /* rfc821_domains = FALSE; << no longer needed */
1026
1027 if (recipient == NULL)
1028 /* The function moan_smtp_batch() does not return. */
1029 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
1030
1031 /* If the recipient address is unqualified, qualify it if permitted. Then
1032 add it to the list of recipients. */
1033
1034 if (recipient_domain == 0)
1035 {
1036 if (allow_unqualified_recipient)
1037 {
1038 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1039 recipient);
1040 recipient = rewrite_address_qualify(recipient, TRUE);
1041 }
1042 /* The function moan_smtp_batch() does not return. */
1043 else moan_smtp_batch(cmd_buffer, "501 recipient address must contain "
1044 "a domain");
1045 }
1046 receive_add_recipient(recipient, -1);
1047 break;
1048
1049
1050 /* The DATA command is legal only if it follows successful MAIL FROM
1051 and RCPT TO commands. This function is complete when a valid DATA
1052 command is encountered. */
1053
1054 case DATA_CMD:
1055 if (sender_address == NULL || recipients_count <= 0)
1056 {
1057 /* The function moan_smtp_batch() does not return. */
1058 if (sender_address == NULL)
1059 moan_smtp_batch(cmd_buffer,
1060 "503 MAIL FROM:<sender> command must precede DATA");
1061 else
1062 moan_smtp_batch(cmd_buffer,
1063 "503 RCPT TO:<recipient> must precede DATA");
1064 }
1065 else
1066 {
1067 done = 3; /* DATA successfully achieved */
1068 message_ended = END_NOTENDED; /* Indicate in middle of message */
1069 }
1070 break;
1071
1072
1073 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1074
1075 case VRFY_CMD:
1076 case EXPN_CMD:
1077 case HELP_CMD:
1078 case NOOP_CMD:
1079 case ETRN_CMD:
1080 bsmtp_transaction_linecount = receive_linecount;
1081 break;
1082
1083
1084 case EOF_CMD:
1085 case QUIT_CMD:
1086 done = 2;
1087 break;
1088
1089
1090 case BADARG_CMD:
1091 /* The function moan_smtp_batch() does not return. */
1092 moan_smtp_batch(cmd_buffer, "501 Unexpected argument data");
1093 break;
1094
1095
1096 case BADCHAR_CMD:
1097 /* The function moan_smtp_batch() does not return. */
1098 moan_smtp_batch(cmd_buffer, "501 Unexpected NULL in SMTP command");
1099 break;
1100
1101
1102 default:
1103 /* The function moan_smtp_batch() does not return. */
1104 moan_smtp_batch(cmd_buffer, "500 Command unrecognized");
1105 break;
1106 }
1107 }
1108
1109return done - 2; /* Convert yield values */
1110}
1111
1112
1113
1114
1115/*************************************************
1116* Start an SMTP session *
1117*************************************************/
1118
1119/* This function is called at the start of an SMTP session. Thereafter,
1120smtp_setup_msg() is called to initiate each separate message. This
1121function does host-specific testing, and outputs the banner line.
1122
1123Arguments: none
1124Returns: FALSE if the session can not continue; something has
1125 gone wrong, or the connection to the host is blocked
1126*/
1127
1128BOOL
1129smtp_start_session(void)
1130{
1131int size = 256;
1132int i, ptr;
1133uschar *p, *s, *ss;
1134
8e669ac1
PH
1135/* If we are running in the test harness, and the incoming call is from
1136127.0.0.2 (sic), have a short delay. This makes it possible to test handling of
00f00ca5
PH
1137input sent too soon (before the banner is output). */
1138
8e669ac1 1139if (running_in_test_harness &&
24031e60
PH
1140 sender_host_address != NULL &&
1141 Ustrcmp(sender_host_address, "127.0.0.2") == 0)
00f00ca5
PH
1142 sleep(1);
1143
1144/* Default values for certain variables */
1145
059ec3d9
PH
1146helo_seen = esmtp = helo_accept_junk = FALSE;
1147count_nonmail = TRUE_UNSET;
1148synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1149smtp_delay_mail = smtp_rlm_base;
1150auth_advertised = FALSE;
1151pipelining_advertised = FALSE;
1152sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1153
1154memset(sender_host_cache, 0, sizeof(sender_host_cache));
1155
1156sender_host_authenticated = NULL;
1157authenticated_by = NULL;
1158
1159#ifdef SUPPORT_TLS
1160tls_cipher = tls_peerdn = NULL;
1161tls_advertised = FALSE;
1162#endif
1163
1164/* Reset ACL connection variables */
1165
1166for (i = 0; i < ACL_C_MAX; i++) acl_var[i] = NULL;
1167
1168cmd_buffer = (uschar *)malloc(cmd_buffer_size + 1); /* allow for trailing 0 */
1169if (cmd_buffer == NULL)
1170 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1171 "malloc() failed for SMTP command buffer");
1172
1173/* For batched input, the protocol setting can be overridden from the
1174command line by a trusted caller. */
1175
1176if (smtp_batched_input)
1177 {
1178 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1179 }
1180
1181/* For non-batched SMTP input, the protocol setting is forced here. It will be
1182reset later if any of EHLO/AUTH/STARTTLS are received. */
1183
1184else
1185 received_protocol =
1186 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1187
1188/* Set up the buffer for inputting using direct read() calls, and arrange to
1189call the local functions instead of the standard C ones. */
1190
1191smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1192if (smtp_inbuffer == NULL)
1193 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1194receive_getc = smtp_getc;
1195receive_ungetc = smtp_ungetc;
1196receive_feof = smtp_feof;
1197receive_ferror = smtp_ferror;
1198smtp_inptr = smtp_inend = smtp_inbuffer;
1199smtp_had_eof = smtp_had_error = 0;
1200
1201/* Set up the message size limit; this may be host-specific */
1202
1203thismessage_size_limit = expand_string_integer(message_size_limit);
1204if (thismessage_size_limit < 0)
1205 {
1206 if (thismessage_size_limit == -1)
1207 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1208 "%s", expand_string_message);
1209 else
1210 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1211 "%s", expand_string_message);
1212 smtp_closedown(US"Temporary local problem - please try later");
1213 return FALSE;
1214 }
1215
1216/* When a message is input locally via the -bs or -bS options, sender_host_
1217unknown is set unless -oMa was used to force an IP address, in which case it
1218is checked like a real remote connection. When -bs is used from inetd, this
1219flag is not set, causing the sending host to be checked. The code that deals
1220with IP source routing (if configured) is never required for -bs or -bS and
1221the flag sender_host_notsocket is used to suppress it.
1222
1223If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1224reserve for certain hosts and/or networks. */
1225
1226if (!sender_host_unknown)
1227 {
1228 int rc;
1229 BOOL reserved_host = FALSE;
1230
1231 /* Look up IP options (source routing info) on the socket if this is not an
1232 -oMa "host", and if any are found, log them and drop the connection.
1233
1234 Linux (and others now, see below) is different to everyone else, so there
1235 has to be some conditional compilation here. Versions of Linux before 2.1.15
1236 used a structure whose name was "options". Somebody finally realized that
1237 this name was silly, and it got changed to "ip_options". I use the
1238 newer name here, but there is a fudge in the script that sets up os.h
1239 to define a macro in older Linux systems.
1240
1241 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1242 glibc 2, which has chosen ip_opts for the structure name. This is now
1243 really a glibc thing rather than a Linux thing, so the condition name
1244 has been changed to reflect this. It is relevant also to GNU/Hurd.
1245
1246 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1247 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1248 a special macro defined in the os.h file.
1249
1250 Some DGUX versions on older hardware appear not to support IP options at
1251 all, so there is now a general macro which can be set to cut out this
1252 support altogether.
1253
1254 How to do this properly in IPv6 is not yet known. */
1255
1256 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1257
1258 #ifdef GLIBC_IP_OPTIONS
1259 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1260 #define OPTSTYLE 1
1261 #else
1262 #define OPTSTYLE 2
1263 #endif
1264 #elif defined DARWIN_IP_OPTIONS
1265 #define OPTSTYLE 2
1266 #else
1267 #define OPTSTYLE 3
1268 #endif
1269
1270 if (!host_checking && !sender_host_notsocket)
1271 {
1272 #if OPTSTYLE == 1
36a3b041 1273 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
059ec3d9
PH
1274 struct ip_options *ipopt = store_get(optlen);
1275 #elif OPTSTYLE == 2
1276 struct ip_opts ipoptblock;
1277 struct ip_opts *ipopt = &ipoptblock;
36a3b041 1278 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
059ec3d9
PH
1279 #else
1280 struct ipoption ipoptblock;
1281 struct ipoption *ipopt = &ipoptblock;
36a3b041 1282 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
059ec3d9
PH
1283 #endif
1284
1285 /* Occasional genuine failures of getsockopt() have been seen - for
1286 example, "reset by peer". Therefore, just log and give up on this
1287 call, unless the error is ENOPROTOOPT. This error is given by systems
1288 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1289 of writing. So for that error, carry on - we just can't do an IP options
1290 check. */
1291
1292 DEBUG(D_receive) debug_printf("checking for IP options\n");
1293
1294 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1295 &optlen) < 0)
1296 {
1297 if (errno != ENOPROTOOPT)
1298 {
1299 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1300 host_and_ident(FALSE), strerror(errno));
1301 smtp_printf("451 SMTP service not available\r\n");
1302 return FALSE;
1303 }
1304 }
1305
1306 /* Deal with any IP options that are set. On the systems I have looked at,
1307 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1308 more logging data than will fit in big_buffer. Nevertheless, after somebody
1309 questioned this code, I've added in some paranoid checking. */
1310
1311 else if (optlen > 0)
1312 {
1313 uschar *p = big_buffer;
1314 uschar *pend = big_buffer + big_buffer_size;
1315 uschar *opt, *adptr;
1316 int optcount;
1317 struct in_addr addr;
1318
1319 #if OPTSTYLE == 1
1320 uschar *optstart = (uschar *)(ipopt->__data);
1321 #elif OPTSTYLE == 2
1322 uschar *optstart = (uschar *)(ipopt->ip_opts);
1323 #else
1324 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1325 #endif
1326
1327 DEBUG(D_receive) debug_printf("IP options exist\n");
1328
1329 Ustrcpy(p, "IP options on incoming call:");
1330 p += Ustrlen(p);
1331
1332 for (opt = optstart; opt != NULL &&
1333 opt < (uschar *)(ipopt) + optlen;)
1334 {
1335 switch (*opt)
1336 {
1337 case IPOPT_EOL:
1338 opt = NULL;
1339 break;
1340
1341 case IPOPT_NOP:
1342 opt++;
1343 break;
1344
1345 case IPOPT_SSRR:
1346 case IPOPT_LSRR:
1347 if (!string_format(p, pend-p, " %s [@%s",
1348 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1349 #if OPTSTYLE == 1
1350 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1351 #elif OPTSTYLE == 2
1352 inet_ntoa(ipopt->ip_dst)))
1353 #else
1354 inet_ntoa(ipopt->ipopt_dst)))
1355 #endif
1356 {
1357 opt = NULL;
1358 break;
1359 }
1360
1361 p += Ustrlen(p);
1362 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1363 adptr = opt + 3;
1364 while (optcount-- > 0)
1365 {
1366 memcpy(&addr, adptr, sizeof(addr));
1367 if (!string_format(p, pend - p - 1, "%s%s",
1368 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1369 {
1370 opt = NULL;
1371 break;
1372 }
1373 p += Ustrlen(p);
1374 adptr += sizeof(struct in_addr);
1375 }
1376 *p++ = ']';
1377 opt += opt[1];
1378 break;
1379
1380 default:
1381 {
1382 int i;
1383 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1384 Ustrcat(p, "[ ");
1385 p += 2;
1386 for (i = 0; i < opt[1]; i++)
1387 {
1388 sprintf(CS p, "%2.2x ", opt[i]);
1389 p += 3;
1390 }
1391 *p++ = ']';
1392 }
1393 opt += opt[1];
1394 break;
1395 }
1396 }
1397
1398 *p = 0;
1399 log_write(0, LOG_MAIN, "%s", big_buffer);
1400
1401 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1402
1403 log_write(0, LOG_MAIN|LOG_REJECT,
1404 "connection from %s refused (IP options)", host_and_ident(FALSE));
1405
1406 smtp_printf("554 SMTP service not available\r\n");
1407 return FALSE;
1408 }
1409
1410 /* Length of options = 0 => there are no options */
1411
1412 else DEBUG(D_receive) debug_printf("no IP options found\n");
1413 }
1414 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1415
1416 /* Set keep-alive in socket options. The option is on by default. This
1417 setting is an attempt to get rid of some hanging connections that stick in
1418 read() when the remote end (usually a dialup) goes away. */
1419
1420 if (smtp_accept_keepalive && !sender_host_notsocket)
1421 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1422
1423 /* If the current host matches host_lookup, set the name by doing a
1424 reverse lookup. On failure, sender_host_name will be NULL and
1425 host_lookup_failed will be TRUE. This may or may not be serious - optional
1426 checks later. */
1427
1428 if (verify_check_host(&host_lookup) == OK)
1429 {
1430 (void)host_name_lookup();
1431 host_build_sender_fullhost();
1432 }
1433
1434 /* Delay this until we have the full name, if it is looked up. */
1435
1436 set_process_info("handling incoming connection from %s",
1437 host_and_ident(FALSE));
1438
1439 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1440 smtps port for use with older style SSL MTAs. */
1441
1442 #ifdef SUPPORT_TLS
1443 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1444 return FALSE;
1445 #endif
1446
1447 /* Test for explicit connection rejection */
1448
1449 if (verify_check_host(&host_reject_connection) == OK)
1450 {
1451 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1452 "from %s (host_reject_connection)", host_and_ident(FALSE));
1453 smtp_printf("554 SMTP service not available\r\n");
1454 return FALSE;
1455 }
1456
1457 /* Test with TCP Wrappers if so configured */
1458
1459 #ifdef USE_TCP_WRAPPERS
1460 if (!hosts_ctl("exim",
1461 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1462 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1463 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1464 {
1465 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1466 log_write(L_connection_reject,
1467 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1468 "(tcp wrappers)", host_and_ident(FALSE));
1469 smtp_printf("554 SMTP service not available\r\n");
1470 return FALSE;
1471 }
1472 #endif
1473
1474 /* Check for reserved slots. Note that the count value doesn't include
1475 this process, as it gets upped in the parent process. */
1476
1477 if (smtp_accept_max > 0 &&
1478 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1479 {
1480 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1481 {
1482 log_write(L_connection_reject,
1483 LOG_MAIN, "temporarily refused connection from %s: not in "
1484 "reserve list: connected=%d max=%d reserve=%d%s",
1485 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1486 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1487 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1488 "please try again later\r\n", smtp_active_hostname);
1489 return FALSE;
1490 }
1491 reserved_host = TRUE;
1492 }
1493
1494 /* If a load level above which only messages from reserved hosts are
1495 accepted is set, check the load. For incoming calls via the daemon, the
1496 check is done in the superior process if there are no reserved hosts, to
1497 save a fork. In all cases, the load average will already be available
1498 in a global variable at this point. */
1499
1500 if (smtp_load_reserve >= 0 &&
1501 load_average > smtp_load_reserve &&
1502 !reserved_host &&
1503 verify_check_host(&smtp_reserve_hosts) != OK)
1504 {
1505 log_write(L_connection_reject,
1506 LOG_MAIN, "temporarily refused connection from %s: not in "
1507 "reserve list and load average = %.2f", host_and_ident(FALSE),
1508 (double)load_average/1000.0);
1509 smtp_printf("421 %s: Too much load; please try again later\r\n",
1510 smtp_active_hostname);
1511 return FALSE;
1512 }
1513
1514 /* Determine whether unqualified senders or recipients are permitted
1515 for this host. Unfortunately, we have to do this every time, in order to
1516 set the flags so that they can be inspected when considering qualifying
1517 addresses in the headers. For a site that permits no qualification, this
1518 won't take long, however. */
1519
1520 allow_unqualified_sender =
1521 verify_check_host(&sender_unqualified_hosts) == OK;
1522
1523 allow_unqualified_recipient =
1524 verify_check_host(&recipient_unqualified_hosts) == OK;
1525
1526 /* Determine whether HELO/EHLO is required for this host. The requirement
1527 can be hard or soft. */
1528
1529 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1530 if (!helo_required)
1531 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1532
1533 /* Determine whether this hosts is permitted to send syntactic junk
1534 after a HELO or EHLO command. */
1535
1536 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1537 }
1538
1539/* For batch SMTP input we are now done. */
1540
1541if (smtp_batched_input) return TRUE;
1542
1543/* Run the ACL if it exists */
1544
1545if (acl_smtp_connect != NULL)
1546 {
1547 int rc;
1548 uschar *user_msg, *log_msg;
64ffc24f 1549 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
059ec3d9
PH
1550 &log_msg);
1551 if (rc != OK)
1552 {
1553 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1554 return FALSE;
1555 }
1556 }
1557
1558/* Output the initial message for a two-way SMTP connection. It may contain
1559newlines, which then cause a multi-line response to be given. */
1560
1561s = expand_string(smtp_banner);
1562if (s == NULL)
1563 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1564 "failed: %s", smtp_banner, expand_string_message);
1565
1566/* Remove any terminating newlines; might as well remove trailing space too */
1567
1568p = s + Ustrlen(s);
1569while (p > s && isspace(p[-1])) p--;
1570*p = 0;
1571
1572/* It seems that CC:Mail is braindead, and assumes that the greeting message
1573is all contained in a single IP packet. The original code wrote out the
1574greeting using several calls to fprint/fputc, and on busy servers this could
1575cause it to be split over more than one packet - which caused CC:Mail to fall
1576over when it got the second part of the greeting after sending its first
1577command. Sigh. To try to avoid this, build the complete greeting message
1578first, and output it in one fell swoop. This gives a better chance of it
1579ending up as a single packet. */
1580
1581ss = store_get(size);
1582ptr = 0;
1583
1584p = s;
1585do /* At least once, in case we have an empty string */
1586 {
1587 int len;
1588 uschar *linebreak = Ustrchr(p, '\n');
1589 if (linebreak == NULL)
1590 {
1591 len = Ustrlen(p);
1592 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1593 }
1594 else
1595 {
1596 len = linebreak - p;
1597 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1598 }
1599 ss = string_cat(ss, &size, &ptr, p, len);
1600 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1601 p += len;
1602 if (linebreak != NULL) p++;
1603 }
1604while (*p != 0);
1605
1606ss[ptr] = 0; /* string_cat leaves room for this */
1607
1608/* Before we write the banner, check that there is no input pending, unless
1609this synchronisation check is disabled. */
1610
1611if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1612 {
1613 fd_set fds;
1614 struct timeval tzero;
1615 tzero.tv_sec = 0;
1616 tzero.tv_usec = 0;
1617 FD_ZERO(&fds);
1618 FD_SET(fileno(smtp_in), &fds);
1619 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1620 &tzero) > 0)
1621 {
00f00ca5 1622 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
f9b9210e
PH
1623 if (rc > 0)
1624 {
1625 if (rc > 150) rc = 150;
1626 smtp_inbuffer[rc] = 0;
3af76a81 1627 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
f9b9210e
PH
1628 "synchronization error (input sent without waiting for greeting): "
1629 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1630 string_printing(smtp_inbuffer));
1631 smtp_printf("554 SMTP synchronization error\r\n");
1632 return FALSE;
1633 }
059ec3d9
PH
1634 }
1635 }
1636
1637/* Now output the banner */
1638
1639smtp_printf("%s", ss);
1640return TRUE;
1641}
1642
1643
1644
1645
1646
1647/*************************************************
1648* Handle SMTP syntax and protocol errors *
1649*************************************************/
1650
1651/* Write to the log for SMTP syntax errors in incoming commands, if configured
1652to do so. Then transmit the error response. The return value depends on the
1653number of syntax and protocol errors in this SMTP session.
1654
1655Arguments:
1656 type error type, given as a log flag bit
1657 code response code; <= 0 means don't send a response
1658 data data to reflect in the response (can be NULL)
1659 errmess the error message
1660
1661Returns: -1 limit of syntax/protocol errors NOT exceeded
1662 +1 limit of syntax/protocol errors IS exceeded
1663
1664These values fit in with the values of the "done" variable in the main
1665processing loop in smtp_setup_msg(). */
1666
1667static int
1668synprot_error(int type, int code, uschar *data, uschar *errmess)
1669{
1670int yield = -1;
1671
1672log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1673 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1674 string_printing(cmd_buffer), host_and_ident(TRUE), errmess);
1675
1676if (++synprot_error_count > smtp_max_synprot_errors)
1677 {
1678 yield = 1;
1679 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1680 "syntax or protocol errors (last command was \"%s\")",
1681 host_and_ident(FALSE), cmd_buffer);
1682 }
1683
1684if (code > 0)
1685 {
1686 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1687 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1688 if (yield == 1)
1689 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1690 }
1691
1692return yield;
1693}
1694
1695
1696
1697
1698/*************************************************
1699* Log incomplete transactions *
1700*************************************************/
1701
1702/* This function is called after a transaction has been aborted by RSET, QUIT,
1703connection drops or other errors. It logs the envelope information received
1704so far in order to preserve address verification attempts.
1705
1706Argument: string to indicate what aborted the transaction
1707Returns: nothing
1708*/
1709
1710static void
1711incomplete_transaction_log(uschar *what)
1712{
1713if (sender_address == NULL || /* No transaction in progress */
1714 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1715 ) return;
1716
1717/* Build list of recipients for logging */
1718
1719if (recipients_count > 0)
1720 {
1721 int i;
1722 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1723 for (i = 0; i < recipients_count; i++)
1724 raw_recipients[i] = recipients_list[i].address;
1725 raw_recipients_count = recipients_count;
1726 }
1727
1728log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1729 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1730}
1731
1732
1733
1734
1735/*************************************************
1736* Send SMTP response, possibly multiline *
1737*************************************************/
1738
1739/* There are, it seems, broken clients out there that cannot handle multiline
1740responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1741output nothing for non-final calls, and only the first line for anything else.
1742
1743Arguments:
1744 code SMTP code
1745 final FALSE if the last line isn't the final line
1746 msg message text, possibly containing newlines
1747
1748Returns: nothing
1749*/
1750
1751void
1752smtp_respond(int code, BOOL final, uschar *msg)
1753{
1754if (!final && no_multiline_responses) return;
1755
1756for (;;)
1757 {
1758 uschar *nl = Ustrchr(msg, '\n');
1759 if (nl == NULL)
1760 {
1761 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1762 return;
1763 }
1764 else if (nl[1] == 0 || no_multiline_responses)
1765 {
1766 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1767 return;
1768 }
1769 else
1770 {
1771 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1772 msg = nl + 1;
1773 while (isspace(*msg)) msg++;
1774 }
1775 }
1776}
1777
1778
1779
1780
1781/*************************************************
1782* Handle an ACL failure *
1783*************************************************/
1784
1785/* This function is called when acl_check() fails. As well as calls from within
1786this module, it is called from receive.c for an ACL after DATA. It sorts out
1787logging the incident, and sets up the error response. A message containing
1788newlines is turned into a multiline SMTP response, but for logging, only the
1789first line is used.
1790
1791There's a table of the response codes to use in globals.c, along with the table
1792of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1793However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1794that the response should be 252 in the disabled state, because there are broken
1795clients that try VRFY before RCPT. A 5xx response should be given only when the
1796address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1797given on refusal, and for AUTH, 503.
1798
1799Arguments:
1800 where where the ACL was called from
1801 rc the failure code
1802 user_msg a message that can be included in an SMTP response
1803 log_msg a message for logging
1804
1805Returns: 0 in most cases
1806 2 if the failure code was FAIL_DROP, in which case the
1807 SMTP connection should be dropped (this value fits with the
1808 "done" variable in smtp_setup_msg() below)
1809*/
1810
1811int
1812smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1813{
1814int code = acl_wherecodes[where];
1815BOOL drop = rc == FAIL_DROP;
1816uschar *lognl;
1817uschar *sender_info = US"";
64ffc24f 1818uschar *what =
8523533c 1819#ifdef WITH_CONTENT_SCAN
64ffc24f 1820 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
8e669ac1 1821#endif
64ffc24f
PH
1822 (where == ACL_WHERE_PREDATA)? US"DATA" :
1823 (where == ACL_WHERE_DATA)? US"after DATA" :
1824 (smtp_command_argument == NULL)?
1825 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
1826 string_sprintf("%s %s", acl_wherenames[where], smtp_command_argument);
059ec3d9
PH
1827
1828if (drop) rc = FAIL;
1829
1830/* We used to have sender_address here; however, there was a bug that was not
1831updating sender_address after a rewrite during a verify. When this bug was
1832fixed, sender_address at this point became the rewritten address. I'm not sure
1833this is what should be logged, so I've changed to logging the unrewritten
1834address to retain backward compatibility. */
1835
8523533c 1836#ifndef WITH_CONTENT_SCAN
059ec3d9 1837if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
8523533c
TK
1838#else
1839if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1840#endif
059ec3d9
PH
1841 {
1842 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1843 sender_address_unrewritten : sender_address);
1844 }
1845
1846/* If there's been a sender verification failure with a specific message, and
1847we have not sent a response about it yet, do so now, as a preliminary line for
1848failures, but not defers. However, log it in both cases. */
1849
1850if (sender_verified_failed != NULL &&
1851 !testflag(sender_verified_failed, af_sverify_told))
1852 {
1853 setflag(sender_verified_failed, af_sverify_told);
1854
1855 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1856 host_and_ident(TRUE),
1857 ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail",
1858 sender_verified_failed->address,
1859 (sender_verified_failed->message == NULL)? US"" :
1860 string_sprintf(": %s", sender_verified_failed->message));
1861
1862 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1863 smtp_respond(code, FALSE, string_sprintf(
1864 testflag(sender_verified_failed, af_verify_pmfail)?
1865 "Postmaster verification failed while checking <%s>\n%s\n"
1866 "Several RFCs state that you are required to have a postmaster\n"
1867 "mailbox for each mail domain. This host does not accept mail\n"
1868 "from domains whose servers reject the postmaster address."
1869 :
1870 testflag(sender_verified_failed, af_verify_nsfail)?
1871 "Callback setup failed while verifying <%s>\n%s\n"
1872 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1873 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1874 "RFC requirements, and stops you from receiving standard bounce\n"
1875 "messages. This host does not accept mail from domains whose servers\n"
1876 "refuse bounces."
1877 :
1878 "Verification failed for <%s>\n%s",
1879 sender_verified_failed->address,
1880 sender_verified_failed->user_message));
1881 }
1882
1883/* Sort out text for logging */
1884
1885log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1886lognl = Ustrchr(log_msg, '\n');
1887if (lognl != NULL) *lognl = 0;
1888
1889/* Send permanent failure response to the command, but the code used isn't
1890always a 5xx one - see comments at the start of this function. If the original
1891rc was FAIL_DROP we drop the connection and yield 2. */
1892
1893if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1894 US"Administrative prohibition" : user_msg);
1895
1896/* Send temporary failure response to the command. Don't give any details,
1897unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1898verb, and for a header verify when smtp_return_error_details is set.
1899
1900This conditional logic is all somewhat of a mess because of the odd
1901interactions between temp_details and return_error_details. One day it should
1902be re-implemented in a tidier fashion. */
1903
1904else
1905 {
1906 if (acl_temp_details && user_msg != NULL)
1907 {
1908 if (smtp_return_error_details &&
1909 sender_verified_failed != NULL &&
1910 sender_verified_failed->message != NULL)
1911 {
1912 smtp_respond(451, FALSE, sender_verified_failed->message);
1913 }
1914 smtp_respond(451, TRUE, user_msg);
1915 }
1916 else
1917 smtp_printf("451 Temporary local problem - please try later\r\n");
1918 }
1919
1920/* Log the incident. If the connection is not forcibly to be dropped, return 0.
1921Otherwise, log why it is closing if required and return 2. */
1922
1923log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1924 host_and_ident(TRUE),
1925 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1926
1927if (!drop) return 0;
1928
1929log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1930 smtp_get_connection_info());
1931return 2;
1932}
1933
1934
1935
1936
1937/*************************************************
d7b47fd0
PH
1938* Verify HELO argument *
1939*************************************************/
1940
1941/* This function is called if helo_verify_hosts or helo_try_verify_hosts is
1942matched. It is also called from ACL processing if verify = helo is used and
1943verification was not previously tried (i.e. helo_try_verify_hosts was not
1944matched). The result of its processing is to set helo_verified and
1945helo_verify_failed. These variables should both be FALSE for this function to
1946be called.
1947
1948Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
1949for IPv6 ::ffff: literals.
1950
1951Argument: none
1952Returns: TRUE if testing was completed;
1953 FALSE on a temporary failure
1954*/
1955
1956BOOL
1957smtp_verify_helo(void)
1958{
1959BOOL yield = TRUE;
1960
1961HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
1962 sender_helo_name);
1963
1964if (sender_helo_name == NULL)
1965 {
1966 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
1967 }
1968
1969else if (sender_helo_name[0] == '[')
1970 {
1971 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
1972 Ustrlen(sender_host_address)) == 0;
1973
1974 #if HAVE_IPV6
1975 if (!helo_verified)
1976 {
1977 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
1978 helo_verified = Ustrncmp(sender_helo_name + 1,
1979 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
1980 }
1981 #endif
1982
1983 HDEBUG(D_receive)
1984 { if (helo_verified) debug_printf("matched host address\n"); }
1985 }
1986
1987/* Do a reverse lookup if one hasn't already given a positive or negative
1988response. If that fails, or the name doesn't match, try checking with a forward
1989lookup. */
1990
1991else
1992 {
1993 if (sender_host_name == NULL && !host_lookup_failed)
1994 yield = host_name_lookup() != DEFER;
1995
1996 /* If a host name is known, check it and all its aliases. */
1997
1998 if (sender_host_name != NULL)
1999 {
2000 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2001
2002 if (helo_verified)
2003 {
2004 HDEBUG(D_receive) debug_printf("matched host name\n");
2005 }
2006 else
2007 {
2008 uschar **aliases = sender_host_aliases;
2009 while (*aliases != NULL)
2010 {
2011 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2012 if (helo_verified) break;
2013 }
2014 HDEBUG(D_receive)
2015 {
2016 if (helo_verified)
2017 debug_printf("matched alias %s\n", *(--aliases));
2018 }
2019 }
2020 }
2021
2022 /* Final attempt: try a forward lookup of the helo name */
2023
2024 if (!helo_verified)
2025 {
2026 int rc;
2027 host_item h;
2028 h.name = sender_helo_name;
2029 h.address = NULL;
2030 h.mx = MX_NONE;
2031 h.next = NULL;
2032 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2033 sender_helo_name);
2034 rc = host_find_byname(&h, NULL, NULL, TRUE);
2035 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2036 {
2037 host_item *hh = &h;
2038 while (hh != NULL)
2039 {
2040 if (Ustrcmp(hh->address, sender_host_address) == 0)
2041 {
2042 helo_verified = TRUE;
2043 HDEBUG(D_receive)
2044 debug_printf("IP address for %s matches calling address\n",
2045 sender_helo_name);
2046 break;
2047 }
2048 hh = hh->next;
2049 }
2050 }
2051 }
2052 }
2053
2054if (!helo_verified) helo_verify_failed = FALSE; /* We've tried ... */
2055return yield;
2056}
2057
2058
2059
2060
2061/*************************************************
059ec3d9
PH
2062* Initialize for SMTP incoming message *
2063*************************************************/
2064
2065/* This function conducts the initial dialogue at the start of an incoming SMTP
2066message, and builds a list of recipients. However, if the incoming message
2067is part of a batch (-bS option) a separate function is called since it would
2068be messy having tests splattered about all over this function. This function
2069therefore handles the case where interaction is occurring. The input and output
2070files are set up in smtp_in and smtp_out.
2071
2072The global recipients_list is set to point to a vector of recipient_item
2073blocks, whose number is given by recipients_count. This is extended by the
2074receive_add_recipient() function. The global variable sender_address is set to
2075the sender's address. The yield is +1 if a message has been successfully
2076started, 0 if a QUIT command was encountered or the connection was refused from
2077the particular host, or -1 if the connection was lost.
2078
2079Argument: none
2080
2081Returns: > 0 message successfully started (reached DATA)
2082 = 0 QUIT read or end of file reached or call refused
2083 < 0 lost connection
2084*/
2085
2086int
2087smtp_setup_msg(void)
2088{
2089int done = 0;
2090BOOL toomany = FALSE;
2091BOOL discarded = FALSE;
2092BOOL last_was_rej_mail = FALSE;
2093BOOL last_was_rcpt = FALSE;
2094void *reset_point = store_get(0);
2095
2096DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2097
2098/* Reset for start of new message. We allow one RSET not to be counted as a
2099nonmail command, for those MTAs that insist on sending it between every
2100message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2101TLS between messages (an Exim client may do this if it has messages queued up
2102for the host). Note: we do NOT reset AUTH at this point. */
2103
2104smtp_reset(reset_point);
2105message_ended = END_NOTSTARTED;
2106
2107cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2108cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2109cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2110#ifdef SUPPORT_TLS
2111cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2112#endif
2113
2114/* Set the local signal handler for SIGTERM - it tries to end off tidily */
2115
2116os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2117
2118/* Batched SMTP is handled in a different function. */
2119
2120if (smtp_batched_input) return smtp_setup_batch_msg();
2121
2122/* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2123value. The values are 2 larger than the required yield of the function. */
2124
2125while (done <= 0)
2126 {
2127 uschar **argv;
2128 uschar *etrn_command;
2129 uschar *etrn_serialize_key;
2130 uschar *errmess;
2131 uschar *user_msg, *log_msg;
2132 uschar *recipient = NULL;
2133 uschar *hello = NULL;
2134 uschar *set_id = NULL;
2135 uschar *s, *ss;
2136 BOOL was_rej_mail = FALSE;
2137 BOOL was_rcpt = FALSE;
2138 void (*oldsignal)(int);
2139 pid_t pid;
2140 int start, end, sender_domain, recipient_domain;
2141 int ptr, size, rc;
2142 int c;
2143 auth_instance *au;
2144
2145 switch(smtp_read_command(TRUE))
2146 {
2147 /* The AUTH command is not permitted to occur inside a transaction, and may
2148 occur successfully only once per connection, and then only when we've
2149 advertised it. Actually, that isn't quite true. When TLS is started, all
2150 previous information about a connection must be discarded, so a new AUTH is
2151 permitted at that time.
2152
2153 AUTH is initially labelled as a "nonmail command" so that one occurrence
2154 doesn't get counted. We change the label here so that multiple failing
2155 AUTHS will eventually hit the nonmail threshold. */
2156
2157 case AUTH_CMD:
2158 authentication_failed = TRUE;
2159 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2160
2161 if (!auth_advertised)
2162 {
2163 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2164 US"AUTH command used when not advertised");
2165 break;
2166 }
2167 if (sender_host_authenticated != NULL)
2168 {
2169 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2170 US"already authenticated");
2171 break;
2172 }
2173 if (sender_address != NULL)
2174 {
2175 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2176 US"not permitted in mail transaction");
2177 break;
2178 }
2179
2180 /* Check the ACL */
2181
2182 if (acl_smtp_auth != NULL)
2183 {
64ffc24f 2184 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
059ec3d9
PH
2185 if (rc != OK)
2186 {
2187 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2188 break;
2189 }
2190 }
2191
2192 /* Find the name of the requested authentication mechanism. */
2193
64ffc24f
PH
2194 s = smtp_command_argument;
2195 while ((c = *smtp_command_argument) != 0 && !isspace(c))
059ec3d9
PH
2196 {
2197 if (!isalnum(c) && c != '-' && c != '_')
2198 {
2199 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2200 US"invalid character in authentication mechanism name");
2201 goto COMMAND_LOOP;
2202 }
64ffc24f 2203 smtp_command_argument++;
059ec3d9
PH
2204 }
2205
2206 /* If not at the end of the line, we must be at white space. Terminate the
2207 name and move the pointer on to any data that may be present. */
2208
64ffc24f 2209 if (*smtp_command_argument != 0)
059ec3d9 2210 {
64ffc24f
PH
2211 *smtp_command_argument++ = 0;
2212 while (isspace(*smtp_command_argument)) smtp_command_argument++;
059ec3d9
PH
2213 }
2214
2215 /* Search for an authentication mechanism which is configured for use
2216 as a server and which has been advertised. */
2217
2218 for (au = auths; au != NULL; au = au->next)
2219 {
2220 if (strcmpic(s, au->public_name) == 0 && au->server &&
2221 au->advertised) break;
2222 }
2223
2224 if (au == NULL)
2225 {
2226 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2227 string_sprintf("%s authentication mechanism not supported", s));
2228 break;
2229 }
2230
2231 /* Run the checking code, passing the remainder of the command
2232 line as data. Initialize $0 empty. The authenticator may set up
2233 other numeric variables. Afterwards, have a go at expanding the set_id
2234 string, even if authentication failed - for bad passwords it can be useful
2235 to log the userid. On success, require set_id to expand and exist, and
2236 put it in authenticated_id. Save this in permanent store, as the working
2237 store gets reset at HELO, RSET, etc. */
2238
2239 expand_nmax = 0;
2240 expand_nlength[0] = 0; /* $0 contains nothing */
2241
64ffc24f 2242 c = (au->info->servercode)(au, smtp_command_argument);
059ec3d9
PH
2243 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2244 expand_nmax = -1; /* Reset numeric variables */
2245
0612b098
PH
2246 /* The value of authenticated_id is stored in the spool file and printed in
2247 log lines. It must not contain binary zeros or newline characters. In
2248 normal use, it never will, but when playing around or testing, this error
2249 can (did) happen. To guard against this, ensure that the id contains only
2250 printing characters. */
2251
2252 if (set_id != NULL) set_id = string_printing(set_id);
2253
059ec3d9
PH
2254 /* For the non-OK cases, set up additional logging data if set_id
2255 is not empty. */
2256
2257 if (c != OK)
2258 {
2259 if (set_id != NULL && *set_id != 0)
2260 set_id = string_sprintf(" (set_id=%s)", set_id);
2261 else set_id = US"";
2262 }
2263
2264 /* Switch on the result */
2265
2266 switch(c)
2267 {
2268 case OK:
2269 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2270 {
2271 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2272 sender_host_authenticated = au->name;
2273 authentication_failed = FALSE;
2274 received_protocol =
2275 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2276 ((sender_host_address != NULL)? pnlocal : 0);
2277 s = ss = US"235 Authentication succeeded";
2278 authenticated_by = au;
2279 break;
2280 }
2281
2282 /* Authentication succeeded, but we failed to expand the set_id string.
2283 Treat this as a temporary error. */
2284
2285 auth_defer_msg = expand_string_message;
2286 /* Fall through */
2287
2288 case DEFER:
2289 s = string_sprintf("435 Unable to authenticate at present%s",
2290 auth_defer_user_msg);
2291 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2292 set_id, auth_defer_msg);
2293 break;
2294
2295 case BAD64:
2296 s = ss = US"501 Invalid base64 data";
2297 break;
2298
2299 case CANCELLED:
2300 s = ss = US"501 Authentication cancelled";
2301 break;
2302
2303 case UNEXPECTED:
2304 s = ss = US"553 Initial data not expected";
2305 break;
2306
2307 case FAIL:
2308 s = US"535 Incorrect authentication data";
2309 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2310 break;
2311
2312 default:
2313 s = US"435 Internal error";
2314 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2315 "check", set_id, c);
2316 break;
2317 }
2318
2319 smtp_printf("%s\r\n", s);
2320 if (c != OK)
2321 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2322 au->name, host_and_ident(FALSE), ss);
2323
2324 break; /* AUTH_CMD */
2325
2326 /* The HELO/EHLO commands are permitted to appear in the middle of a
2327 session as well as at the beginning. They have the effect of a reset in
2328 addition to their other functions. Their absence at the start cannot be
2329 taken to be an error.
2330
2331 RFC 2821 says:
2332
2333 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2334 or 502 failure replies MUST be returned as appropriate. The SMTP
2335 server MUST stay in the same state after transmitting these replies
2336 that it was in before the EHLO was received.
2337
2338 Therefore, we do not do the reset until after checking the command for
2339 acceptability. This change was made for Exim release 4.11. Previously
2340 it did the reset first. */
2341
2342 case HELO_CMD:
2343 hello = US"HELO";
2344 esmtp = FALSE;
2345 goto HELO_EHLO;
2346
2347 case EHLO_CMD:
2348 hello = US"EHLO";
2349 esmtp = TRUE;
2350
2351 HELO_EHLO: /* Common code for HELO and EHLO */
2352 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2353 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2354
2355 /* Reject the HELO if its argument was invalid or non-existent. A
2356 successful check causes the argument to be saved in malloc store. */
2357
64ffc24f 2358 if (!check_helo(smtp_command_argument))
059ec3d9
PH
2359 {
2360 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2361
2362 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2363 "invalid argument(s): %s", hello, host_and_ident(FALSE),
64ffc24f
PH
2364 (*smtp_command_argument == 0)? US"(no argument given)" :
2365 string_printing(smtp_command_argument));
059ec3d9
PH
2366
2367 if (++synprot_error_count > smtp_max_synprot_errors)
2368 {
2369 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2370 "syntax or protocol errors (last command was \"%s\")",
2371 host_and_ident(FALSE), cmd_buffer);
2372 done = 1;
2373 }
2374
2375 break;
2376 }
2377
2378 /* If sender_host_unknown is true, we have got here via the -bs interface,
2379 not called from inetd. Otherwise, we are running an IP connection and the
2380 host address will be set. If the helo name is the primary name of this
2381 host and we haven't done a reverse lookup, force one now. If helo_required
2382 is set, ensure that the HELO name matches the actual host. If helo_verify
2383 is set, do the same check, but softly. */
2384
2385 if (!sender_host_unknown)
2386 {
2387 BOOL old_helo_verified = helo_verified;
64ffc24f 2388 uschar *p = smtp_command_argument;
059ec3d9
PH
2389
2390 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2391 *p = 0;
2392
2393 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2394 because otherwise the log can be confusing. */
2395
2396 if (sender_host_name == NULL &&
2397 (deliver_domain = sender_helo_name, /* set $domain */
2398 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2399 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2400 (void)host_name_lookup();
2401
2402 /* Rebuild the fullhost info to include the HELO name (and the real name
2403 if it was looked up.) */
2404
2405 host_build_sender_fullhost(); /* Rebuild */
2406 set_process_info("handling%s incoming connection from %s",
2407 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2408
2409 /* Verify if configured. This doesn't give much security, but it does
d7b47fd0
PH
2410 make some people happy to be able to do it. If helo_required is set,
2411 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2412 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2413 now obsolescent, since the verification can now be requested selectively
2414 at ACL time. */
059ec3d9 2415
d7b47fd0 2416 helo_verified = helo_verify_failed = FALSE;
059ec3d9
PH
2417 if (helo_required || helo_verify)
2418 {
d7b47fd0 2419 BOOL tempfail = !smtp_verify_helo();
059ec3d9
PH
2420 if (!helo_verified)
2421 {
2422 if (helo_required)
2423 {
2424 smtp_printf("%d %s argument does not match calling host\r\n",
2425 tempfail? 451 : 550, hello);
2426 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2427 tempfail? "temporarily " : "",
2428 hello, sender_helo_name, host_and_ident(FALSE));
2429 helo_verified = old_helo_verified;
2430 break; /* End of HELO/EHLO processing */
2431 }
2432 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2433 "helo_try_verify_hosts\n", hello);
2434 }
2435 }
2436 }
2437
8523533c
TK
2438#ifdef EXPERIMENTAL_SPF
2439 /* set up SPF context */
2440 spf_init(sender_helo_name, sender_host_address);
2441#endif
2442
059ec3d9
PH
2443 /* Apply an ACL check if one is defined */
2444
2445 if (acl_smtp_helo != NULL)
2446 {
64ffc24f 2447 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
059ec3d9
PH
2448 if (rc != OK)
2449 {
2450 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2451 sender_helo_name = NULL;
2452 host_build_sender_fullhost(); /* Rebuild */
2453 break;
2454 }
2455 }
2456
2457 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2458 abandoning any previous message. */
2459
2460 received_protocol = (esmtp?
2461 protocols[pextend +
2462 ((sender_host_authenticated != NULL)? pauthed : 0) +
2463 ((tls_active >= 0)? pcrpted : 0)]
2464 :
981756db 2465 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
059ec3d9
PH
2466 +
2467 ((sender_host_address != NULL)? pnlocal : 0);
2468
2469 smtp_reset(reset_point);
2470 toomany = FALSE;
2471
2472 /* Generate an OK reply, including the ident if present, and also
2473 the IP address if present. Reflecting back the ident is intended
2474 as a deterrent to mail forgers. For maximum efficiency, and also
2475 because some broken systems expect each response to be in a single
2476 packet, arrange that it is sent in one write(). */
2477
2478 auth_advertised = FALSE;
2479 pipelining_advertised = FALSE;
2480 #ifdef SUPPORT_TLS
2481 tls_advertised = FALSE;
2482 #endif
2483
2484 s = string_sprintf("250 %s Hello %s%s%s",
2485 smtp_active_hostname,
2486 (sender_ident == NULL)? US"" : sender_ident,
2487 (sender_ident == NULL)? US"" : US" at ",
2488 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2489
2490 ptr = Ustrlen(s);
2491 size = ptr + 1;
2492
2493 if (sender_host_address != NULL)
2494 {
2495 s = string_cat(s, &size, &ptr, US" [", 2);
2496 s = string_cat(s, &size, &ptr, sender_host_address,
2497 Ustrlen(sender_host_address));
2498 s = string_cat(s, &size, &ptr, US"]", 1);
2499 }
2500
2501 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2502
2503 /* If we received EHLO, we must create a multiline response which includes
2504 the functions supported. */
2505
2506 if (esmtp)
2507 {
2508 s[3] = '-';
2509
2510 /* I'm not entirely happy with this, as an MTA is supposed to check
2511 that it has enough room to accept a message of maximum size before
2512 it sends this. However, there seems little point in not sending it.
2513 The actual size check happens later at MAIL FROM time. By postponing it
2514 till then, VRFY and EXPN can be used after EHLO when space is short. */
2515
2516 if (thismessage_size_limit > 0)
2517 {
2518 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2519 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2520 }
2521 else
2522 {
2523 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2524 }
2525
2526 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2527 clean; if it has an 8-bit character in its hand, it just sends it. It
2528 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2529 However, some users want this option simply in order to stop MUAs
2530 mangling messages that contain top-bit-set characters. It is therefore
2531 provided as an option. */
2532
2533 if (accept_8bitmime)
2534 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2535
2536 /* Advertise ETRN if there's an ACL checking whether a host is
2537 permitted to issue it; a check is made when any host actually tries. */
2538
2539 if (acl_smtp_etrn != NULL)
2540 {
2541 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2542 }
2543
2544 /* Advertise EXPN if there's an ACL checking whether a host is
2545 permitted to issue it; a check is made when any host actually tries. */
2546
2547 if (acl_smtp_expn != NULL)
2548 {
2549 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2550 }
2551
2552 /* Exim is quite happy with pipelining, so let the other end know that
2553 it is safe to use it, unless advertising is disabled. */
2554
2555 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2556 {
2557 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2558 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2559 pipelining_advertised = TRUE;
2560 }
2561
2562 /* If any server authentication mechanisms are configured, advertise
2563 them if the current host is in auth_advertise_hosts. The problem with
2564 advertising always is that some clients then require users to
2565 authenticate (and aren't configurable otherwise) even though it may not
2566 be necessary (e.g. if the host is in host_accept_relay).
2567
2568 RFC 2222 states that SASL mechanism names contain only upper case
2569 letters, so output the names in upper case, though we actually recognize
2570 them in either case in the AUTH command. */
2571
2572 if (auths != NULL)
2573 {
2574 if (verify_check_host(&auth_advertise_hosts) == OK)
2575 {
2576 auth_instance *au;
2577 BOOL first = TRUE;
2578 for (au = auths; au != NULL; au = au->next)
2579 {
2580 if (au->server && (au->advertise_condition == NULL ||
2581 expand_check_condition(au->advertise_condition, au->name,
2582 US"authenticator")))
2583 {
2584 int saveptr;
2585 if (first)
2586 {
2587 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2588 first = FALSE;
2589 auth_advertised = TRUE;
2590 }
2591 saveptr = ptr;
2592 s = string_cat(s, &size, &ptr, US" ", 1);
2593 s = string_cat(s, &size, &ptr, au->public_name,
2594 Ustrlen(au->public_name));
2595 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2596 au->advertised = TRUE;
2597 }
2598 else au->advertised = FALSE;
2599 }
2600 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2601 }
2602 }
2603
2604 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2605 if it has been included in the binary, and the host matches
2606 tls_advertise_hosts. We must *not* advertise if we are already in a
2607 secure connection. */
2608
2609 #ifdef SUPPORT_TLS
2610 if (tls_active < 0 &&
2611 verify_check_host(&tls_advertise_hosts) != FAIL)
2612 {
2613 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2614 tls_advertised = TRUE;
2615 }
2616 #endif
2617
2618 /* Finish off the multiline reply with one that is always available. */
2619
2620 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2621 }
2622
2623 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2624 has been seen. */
2625
2626 s[ptr] = 0;
2627
2628 #ifdef SUPPORT_TLS
2629 if (tls_active >= 0) (void)tls_write(s, ptr); else
2630 #endif
2631
f1e894f3 2632 (void)fwrite(s, 1, ptr, smtp_out);
059ec3d9
PH
2633 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2634 helo_seen = TRUE;
2635 break; /* HELO/EHLO */
2636
2637
2638 /* The MAIL command requires an address as an operand. All we do
2639 here is to parse it for syntactic correctness. The form "<>" is
2640 a special case which converts into an empty string. The start/end
2641 pointers in the original are not used further for this address, as
2642 it is the canonical extracted address which is all that is kept. */
2643
2644 case MAIL_CMD:
2645 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2646 was_rej_mail = TRUE; /* Reset if accepted */
2647
2648 if (helo_required && !helo_seen)
2649 {
2650 smtp_printf("503 HELO or EHLO required\r\n");
2651 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2652 "HELO/EHLO given", host_and_ident(FALSE));
2653 break;
2654 }
2655
2656 if (sender_address != NULL)
2657 {
2658 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2659 US"sender already given");
2660 break;
2661 }
2662
64ffc24f 2663 if (smtp_command_argument[0] == 0)
059ec3d9
PH
2664 {
2665 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2666 US"MAIL must have an address operand");
2667 break;
2668 }
2669
2670 /* Check to see if the limit for messages per connection would be
2671 exceeded by accepting further messages. */
2672
2673 if (smtp_accept_max_per_connection > 0 &&
2674 smtp_mailcmd_count > smtp_accept_max_per_connection)
2675 {
2676 smtp_printf("421 too many messages in this connection\r\n");
2677 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2678 "messages in one connection", host_and_ident(TRUE));
2679 break;
2680 }
2681
2682 /* Reset for start of message - even if this is going to fail, we
2683 obviously need to throw away any previous data. */
2684
2685 smtp_reset(reset_point);
2686 toomany = FALSE;
2687 sender_data = recipient_data = NULL;
2688
2689 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2690
2691 if (esmtp) for(;;)
2692 {
2693 uschar *name, *value, *end;
2694 unsigned long int size;
2695
2696 if (!extract_option(&name, &value)) break;
2697
2698 /* Handle SIZE= by reading the value. We don't do the check till later,
2699 in order to be able to log the sender address on failure. */
2700
2701 if (strcmpic(name, US"SIZE") == 0 &&
2702 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2703 {
2704 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2705 size = INT_MAX;
2706 message_size = (int)size;
2707 }
2708
2709 /* If this session was initiated with EHLO and accept_8bitmime is set,
2710 Exim will have indicated that it supports the BODY=8BITMIME option. In
2711 fact, it does not support this according to the RFCs, in that it does not
2712 take any special action for forwarding messages containing 8-bit
2713 characters. That is why accept_8bitmime is not the default setting, but
2714 some sites want the action that is provided. We recognize both "8BITMIME"
2715 and "7BIT" as body types, but take no action. */
2716
2717 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2718 (strcmpic(value, US"8BITMIME") == 0 ||
2719 strcmpic(value, US"7BIT") == 0)) {}
2720
2721 /* Handle the AUTH extension. If the value given is not "<>" and either
2722 the ACL says "yes" or there is no ACL but the sending host is
2723 authenticated, we set it up as the authenticated sender. However, if the
2724 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2725 the condition is met. The value of AUTH is an xtext, which means that +,
2726 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2727 coding. */
2728
2729 else if (strcmpic(name, US"AUTH") == 0)
2730 {
2731 if (Ustrcmp(value, "<>") != 0)
2732 {
2733 int rc;
2734 uschar *ignore_msg;
2735
2736 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2737 {
2738 /* Put back terminator overrides for error message */
2739 name[-1] = ' ';
2740 value[-1] = '=';
2741 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2742 US"invalid data for AUTH");
2743 goto COMMAND_LOOP;
2744 }
2745
2746 if (acl_smtp_mailauth == NULL)
2747 {
2748 ignore_msg = US"client not authenticated";
2749 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2750 }
2751 else
2752 {
2753 ignore_msg = US"rejected by ACL";
2754 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2755 &user_msg, &log_msg);
2756 }
2757
2758 switch (rc)
2759 {
2760 case OK:
2761 if (authenticated_by == NULL ||
2762 authenticated_by->mail_auth_condition == NULL ||
2763 expand_check_condition(authenticated_by->mail_auth_condition,
2764 authenticated_by->name, US"authenticator"))
2765 break; /* Accept the AUTH */
2766
2767 ignore_msg = US"server_mail_auth_condition failed";
2768 if (authenticated_id != NULL)
2769 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2770 ignore_msg, authenticated_id);
2771
2772 /* Fall through */
2773
2774 case FAIL:
2775 authenticated_sender = NULL;
2776 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2777 value, host_and_ident(TRUE), ignore_msg);
2778 break;
2779
2780 /* Should only get DEFER or ERROR here. Put back terminator
2781 overrides for error message */
2782
2783 default:
2784 name[-1] = ' ';
2785 value[-1] = '=';
2786 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2787 log_msg);
2788 goto COMMAND_LOOP;
2789 }
2790 }
2791 }
2792
2793 /* Unknown option. Stick back the terminator characters and break
2794 the loop. An error for a malformed address will occur. */
2795
2796 else
2797 {
2798 name[-1] = ' ';
2799 value[-1] = '=';
2800 break;
2801 }
2802 }
2803
2804 /* If we have passed the threshold for rate limiting, apply the current
2805 delay, and update it for next time, provided this is a limited host. */
2806
2807 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2808 verify_check_host(&smtp_ratelimit_hosts) == OK)
2809 {
2810 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2811 smtp_delay_mail/1000.0);
2812 millisleep((int)smtp_delay_mail);
2813 smtp_delay_mail *= smtp_rlm_factor;
2814 if (smtp_delay_mail > (double)smtp_rlm_limit)
2815 smtp_delay_mail = (double)smtp_rlm_limit;
2816 }
2817
2818 /* Now extract the address, first applying any SMTP-time rewriting. The
2819 TRUE flag allows "<>" as a sender address. */
2820
2821 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
64ffc24f
PH
2822 rewrite_one(smtp_command_argument, rewrite_smtp, NULL, FALSE, US"",
2823 global_rewrite_rules) : smtp_command_argument;
059ec3d9
PH
2824
2825 /* rfc821_domains = TRUE; << no longer needed */
2826 raw_sender =
2827 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2828 TRUE);
2829 /* rfc821_domains = FALSE; << no longer needed */
2830
2831 if (raw_sender == NULL)
2832 {
64ffc24f 2833 done = synprot_error(L_smtp_syntax_error, 501, smtp_command_argument, errmess);
059ec3d9
PH
2834 break;
2835 }
2836
2837 sender_address = raw_sender;
2838
2839 /* If there is a configured size limit for mail, check that this message
2840 doesn't exceed it. The check is postponed to this point so that the sender
2841 can be logged. */
2842
2843 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2844 {
2845 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2846 log_write(L_size_reject,
2847 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2848 "message too big: size%s=%d max=%d",
2849 sender_address,
2850 host_and_ident(TRUE),
2851 (message_size == INT_MAX)? ">" : "",
2852 message_size,
2853 thismessage_size_limit);
2854 sender_address = NULL;
2855 break;
2856 }
2857
2858 /* Check there is enough space on the disk unless configured not to.
2859 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2860 plus the current message - i.e. we accept the message only if it won't
2861 reduce the space below the threshold. Add 5000 to the size to allow for
2862 overheads such as the Received: line and storing of recipients, etc.
2863 By putting the check here, even when SIZE is not given, it allow VRFY
2864 and EXPN etc. to be used when space is short. */
2865
2866 if (!receive_check_fs(
2867 (smtp_check_spool_space && message_size >= 0)?
2868 message_size + 5000 : 0))
2869 {
2870 smtp_printf("452 Space shortage, please try later\r\n");
2871 sender_address = NULL;
2872 break;
2873 }
2874
2875 /* If sender_address is unqualified, reject it, unless this is a locally
2876 generated message, or the sending host or net is permitted to send
2877 unqualified addresses - typically local machines behaving as MUAs -
2878 in which case just qualify the address. The flag is set above at the start
2879 of the SMTP connection. */
2880
2881 if (sender_domain == 0 && sender_address[0] != 0)
2882 {
2883 if (allow_unqualified_sender)
2884 {
2885 sender_domain = Ustrlen(sender_address) + 1;
2886 sender_address = rewrite_address_qualify(sender_address, FALSE);
2887 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2888 raw_sender);
2889 }
2890 else
2891 {
2892 smtp_printf("501 %s: sender address must contain a domain\r\n",
64ffc24f 2893 smtp_command_argument);
059ec3d9
PH
2894 log_write(L_smtp_syntax_error,
2895 LOG_MAIN|LOG_REJECT,
2896 "unqualified sender rejected: <%s> %s%s",
2897 raw_sender,
2898 host_and_ident(TRUE),
2899 host_lookup_msg);
2900 sender_address = NULL;
2901 break;
2902 }
2903 }
2904
2905 /* Apply an ACL check if one is defined, before responding */
2906
2907 rc = (acl_smtp_mail == NULL)? OK :
2908 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2909
2910 if (rc == OK || rc == DISCARD)
2911 {
2912 smtp_printf("250 OK\r\n");
2913 smtp_delay_rcpt = smtp_rlr_base;
2914 recipients_discarded = (rc == DISCARD);
2915 was_rej_mail = FALSE;
2916 }
2917
2918 else
2919 {
2920 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2921 sender_address = NULL;
2922 }
2923 break;
2924
2925
2926 /* The RCPT command requires an address as an operand. All we do
2927 here is to parse it for syntactic correctness. There may be any number
2928 of RCPT commands, specifying multiple senders. We build them all into
2929 a data structure that is in argc/argv format. The start/end values
2930 given by parse_extract_address are not used, as we keep only the
2931 extracted address. */
2932
2933 case RCPT_CMD:
2934 rcpt_count++;
2935 was_rcpt = TRUE;
2936
2937 /* There must be a sender address; if the sender was rejected and
2938 pipelining was advertised, we assume the client was pipelining, and do not
2939 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2940 get the same treatment. */
2941
2942 if (sender_address == NULL)
2943 {
2944 if (pipelining_advertised && last_was_rej_mail)
2945 {
2946 smtp_printf("503 sender not yet given\r\n");
2947 was_rej_mail = TRUE;
2948 }
2949 else
2950 {
2951 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2952 US"sender not yet given");
2953 was_rcpt = FALSE; /* Not a valid RCPT */
2954 }
2955 rcpt_fail_count++;
2956 break;
2957 }
2958
2959 /* Check for an operand */
2960
64ffc24f 2961 if (smtp_command_argument[0] == 0)
059ec3d9
PH
2962 {
2963 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2964 US"RCPT must have an address operand");
2965 rcpt_fail_count++;
2966 break;
2967 }
2968
2969 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2970 as a recipient address */
2971
2972 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
64ffc24f
PH
2973 rewrite_one(smtp_command_argument, rewrite_smtp, NULL, FALSE, US"",
2974 global_rewrite_rules) : smtp_command_argument;
059ec3d9
PH
2975
2976 /* rfc821_domains = TRUE; << no longer needed */
2977 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2978 &recipient_domain, FALSE);
2979 /* rfc821_domains = FALSE; << no longer needed */
2980
2981 if (recipient == NULL)
2982 {
64ffc24f 2983 done = synprot_error(L_smtp_syntax_error, 501, smtp_command_argument, errmess);
059ec3d9
PH
2984 rcpt_fail_count++;
2985 break;
2986 }
2987
2988 /* If the recipient address is unqualified, reject it, unless this is a
2989 locally generated message. However, unqualified addresses are permitted
2990 from a configured list of hosts and nets - typically when behaving as
2991 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2992 really. The flag is set at the start of the SMTP connection.
2993
2994 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2995 assumed this meant "reserved local part", but the revision of RFC 821 and
2996 friends now makes it absolutely clear that it means *mailbox*. Consequently
2997 we must always qualify this address, regardless. */
2998
2999 if (recipient_domain == 0)
3000 {
3001 if (allow_unqualified_recipient ||
3002 strcmpic(recipient, US"postmaster") == 0)
3003 {
3004 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3005 recipient);
3006 recipient_domain = Ustrlen(recipient) + 1;
3007 recipient = rewrite_address_qualify(recipient, TRUE);
3008 }
3009 else
3010 {
3011 rcpt_fail_count++;
3012 smtp_printf("501 %s: recipient address must contain a domain\r\n",
64ffc24f 3013 smtp_command_argument);
059ec3d9
PH
3014 log_write(L_smtp_syntax_error,
3015 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3016 "<%s> %s%s", recipient, host_and_ident(TRUE),
3017 host_lookup_msg);
3018 break;
3019 }
3020 }
3021
3022 /* Check maximum allowed */
3023
3024 if (rcpt_count > recipients_max && recipients_max > 0)
3025 {
3026 if (recipients_max_reject)
3027 {
3028 rcpt_fail_count++;
3029 smtp_printf("552 too many recipients\r\n");
3030 if (!toomany)
3031 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3032 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3033 }
3034 else
3035 {
3036 rcpt_defer_count++;
3037 smtp_printf("452 too many recipients\r\n");
3038 if (!toomany)
3039 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3040 "temporarily rejected: sender=<%s> %s", sender_address,
3041 host_and_ident(TRUE));
3042 }
3043
3044 toomany = TRUE;
3045 break;
3046 }
3047
3048 /* If we have passed the threshold for rate limiting, apply the current
3049 delay, and update it for next time, provided this is a limited host. */
3050
3051 if (rcpt_count > smtp_rlr_threshold &&
3052 verify_check_host(&smtp_ratelimit_hosts) == OK)
3053 {
3054 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3055 smtp_delay_rcpt/1000.0);
3056 millisleep((int)smtp_delay_rcpt);
3057 smtp_delay_rcpt *= smtp_rlr_factor;
3058 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3059 smtp_delay_rcpt = (double)smtp_rlr_limit;
3060 }
3061
3062 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3063 for them. Otherwise, check the access control list for this recipient. */
3064
3065 rc = recipients_discarded? DISCARD :
3066 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3067
3068 /* The ACL was happy */
3069
3070 if (rc == OK)
3071 {
3072 smtp_printf("250 Accepted\r\n");
3073 receive_add_recipient(recipient, -1);
3074 }
3075
3076 /* The recipient was discarded */
3077
3078 else if (rc == DISCARD)
3079 {
3080 smtp_printf("250 Accepted\r\n");
3081 rcpt_fail_count++;
3082 discarded = TRUE;
3083 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3084 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3085 (sender_address_unrewritten != NULL)?
3086 sender_address_unrewritten : sender_address,
64ffc24f 3087 smtp_command_argument, recipients_discarded? "MAIL" : "RCPT",
059ec3d9
PH
3088 (log_msg == NULL)? US"" : US": ",
3089 (log_msg == NULL)? US"" : log_msg);
3090 }
3091
3092 /* Either the ACL failed the address, or it was deferred. */
3093
3094 else
3095 {
3096 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3097 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3098 }
3099 break;
3100
3101
3102 /* The DATA command is legal only if it follows successful MAIL FROM
3103 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3104 not counted as a protocol error if it follows RCPT (which must have been
3105 rejected if there are no recipients.) This function is complete when a
3106 valid DATA command is encountered.
3107
3108 Note concerning the code used: RFC 2821 says this:
3109
3110 - If there was no MAIL, or no RCPT, command, or all such commands
3111 were rejected, the server MAY return a "command out of sequence"
3112 (503) or "no valid recipients" (554) reply in response to the
3113 DATA command.
3114
3115 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3116 because it is the same whether pipelining is in use or not. */
3117
3118 case DATA_CMD:
3119 if (!discarded && recipients_count <= 0)
3120 {
3121 if (pipelining_advertised && last_was_rcpt)
3122 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3123 else
3124 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3125 US"valid RCPT command must precede DATA");
3126 break;
3127 }
3128
3129 if (toomany && recipients_max_reject)
3130 {
3131 sender_address = NULL; /* This will allow a new MAIL without RSET */
3132 sender_address_unrewritten = NULL;
3133 smtp_printf("554 Too many recipients\r\n");
3134 break;
3135 }
8e669ac1 3136
5be20824 3137 if (acl_smtp_predata == NULL) rc = OK; else
8e669ac1 3138 {
5be20824 3139 enable_dollar_recipients = TRUE;
8e669ac1 3140 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
5be20824
PH
3141 &log_msg);
3142 enable_dollar_recipients = FALSE;
3143 }
059ec3d9
PH
3144
3145 if (rc == OK)
3146 {
3147 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3148 done = 3;
3149 message_ended = END_NOTENDED; /* Indicate in middle of data */
3150 }
3151
3152 /* Either the ACL failed the address, or it was deferred. */
3153
3154 else
3155 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3156
3157 break;
3158
3159
3160 case VRFY_CMD:
64ffc24f 3161 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
059ec3d9
PH
3162 if (rc != OK)
3163 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3164 else
3165 {
3166 uschar *address;
3167 uschar *s = NULL;
3168
3169 /* rfc821_domains = TRUE; << no longer needed */
64ffc24f 3170 address = parse_extract_address(smtp_command_argument, &errmess, &start, &end,
059ec3d9
PH
3171 &recipient_domain, FALSE);
3172 /* rfc821_domains = FALSE; << no longer needed */
3173
3174 if (address == NULL)
3175 s = string_sprintf("501 %s", errmess);
3176 else
3177 {
3178 address_item *addr = deliver_make_addr(address, FALSE);
3179 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
4deaf07d 3180 -1, -1, NULL, NULL, NULL))
059ec3d9
PH
3181 {
3182 case OK:
3183 s = string_sprintf("250 <%s> is deliverable", address);
3184 break;
3185
3186 case DEFER:
3187 s = (addr->message != NULL)?
3188 string_sprintf("451 <%s> %s", address, addr->message) :
3189 string_sprintf("451 Cannot resolve <%s> at this time", address);
3190 break;
3191
3192 case FAIL:
3193 s = (addr->message != NULL)?
3194 string_sprintf("550 <%s> %s", address, addr->message) :
3195 string_sprintf("550 <%s> is not deliverable", address);
3196 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
64ffc24f 3197 smtp_command_argument, host_and_ident(TRUE));
059ec3d9
PH
3198 break;
3199 }
3200 }
3201
3202 smtp_printf("%s\r\n", s);
3203 }
3204 break;
3205
3206
3207 case EXPN_CMD:
64ffc24f 3208 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
059ec3d9
PH
3209 if (rc != OK)
3210 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3211 else
3212 {
3213 BOOL save_log_testing_mode = log_testing_mode;
3214 address_test_mode = log_testing_mode = TRUE;
64ffc24f
PH
3215 (void) verify_address(deliver_make_addr(smtp_command_argument, FALSE),
3216 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3217 NULL, NULL, NULL);
059ec3d9
PH
3218 address_test_mode = FALSE;
3219 log_testing_mode = save_log_testing_mode; /* true for -bh */
3220 }
3221 break;
3222
3223
3224 #ifdef SUPPORT_TLS
3225
3226 case STARTTLS_CMD:
3227 if (!tls_advertised)
3228 {
3229 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3230 US"STARTTLS command used when not advertised");
3231 break;
3232 }
3233
3234 /* Apply an ACL check if one is defined */
3235
3236 if (acl_smtp_starttls != NULL)
3237 {
3238 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3239 &log_msg);
3240 if (rc != OK)
3241 {
3242 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3243 break;
3244 }
3245 }
3246
3247 /* RFC 2487 is not clear on when this command may be sent, though it
3248 does state that all information previously obtained from the client
3249 must be discarded if a TLS session is started. It seems reasonble to
3250 do an implied RSET when STARTTLS is received. */
3251
3252 incomplete_transaction_log(US"STARTTLS");
3253 smtp_reset(reset_point);
3254 toomany = FALSE;
3255 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3256
3257 /* Attempt to start up a TLS session, and if successful, discard all
3258 knowledge that was obtained previously. At least, that's what the RFC says,
3259 and that's what happens by default. However, in order to work round YAEB,
3260 there is an option to remember the esmtp state. Sigh.
3261
3262 We must allow for an extra EHLO command and an extra AUTH command after
3263 STARTTLS that don't add to the nonmail command count. */
3264
3265 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3266 {
3267 if (!tls_remember_esmtp)
3268 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3269 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3270 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3271 if (sender_helo_name != NULL)
3272 {
3273 store_free(sender_helo_name);
3274 sender_helo_name = NULL;
3275 host_build_sender_fullhost(); /* Rebuild */
3276 set_process_info("handling incoming TLS connection from %s",
3277 host_and_ident(FALSE));
3278 }
3279 received_protocol = (esmtp?
3280 protocols[pextend + pcrpted +
3281 ((sender_host_authenticated != NULL)? pauthed : 0)]
3282 :
981756db 3283 protocols[pnormal + pcrpted])
059ec3d9
PH
3284 +
3285 ((sender_host_address != NULL)? pnlocal : 0);
3286
3287 sender_host_authenticated = NULL;
3288 authenticated_id = NULL;
3289 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3290 DEBUG(D_tls) debug_printf("TLS active\n");
3291 break; /* Successful STARTTLS */
3292 }
3293
3294 /* Some local configuration problem was discovered before actually trying
3295 to do a TLS handshake; give a temporary error. */
3296
3297 else if (rc == DEFER)
3298 {
3299 smtp_printf("454 TLS currently unavailable\r\n");
3300 break;
3301 }
3302
3303 /* Hard failure. Reject everything except QUIT or closed connection. One
3304 cause for failure is a nested STARTTLS, in which case tls_active remains
3305 set, but we must still reject all incoming commands. */
3306
3307 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3308 while (done <= 0)
3309 {
3310 switch(smtp_read_command(FALSE))
3311 {
3312 case EOF_CMD:
3313 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3314 smtp_get_connection_info());
3315 done = 2;
3316 break;
3317
3318 case QUIT_CMD:
3319 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3320 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3321 smtp_get_connection_info());
3322 done = 2;
3323 break;
3324
3325 default:
3326 smtp_printf("554 Security failure\r\n");
3327 break;
3328 }
3329 }
3330 tls_close(TRUE);
3331 break;
3332 #endif
3333
3334
3335 /* The ACL for QUIT is provided for gathering statistical information or
3336 similar; it does not affect the response code, but it can supply a custom
3337 message. */
3338
3339 case QUIT_CMD:
3340 incomplete_transaction_log(US"QUIT");
3341
3342 if (acl_smtp_quit != NULL)
3343 {
64ffc24f 3344 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit,&user_msg,&log_msg);
059ec3d9
PH
3345 if (rc == ERROR)
3346 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3347 log_msg);
3348 }
3349 else user_msg = NULL;
3350
3351 if (user_msg == NULL)
3352 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3353 else
3354 smtp_printf("221 %s\r\n", user_msg);
3355
3356 #ifdef SUPPORT_TLS
3357 tls_close(TRUE);
3358 #endif
3359
3360 done = 2;
3361 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3362 smtp_get_connection_info());
3363 break;
3364
3365
3366 case RSET_CMD:
3367 incomplete_transaction_log(US"RSET");
3368 smtp_reset(reset_point);
3369 toomany = FALSE;
3370 smtp_printf("250 Reset OK\r\n");
3371 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3372 break;
3373
3374
3375 case NOOP_CMD:
3376 smtp_printf("250 OK\r\n");
3377 break;
3378
3379
3380 /* Show ETRN/EXPN/VRFY if there's
3381 an ACL for checking hosts; if actually used, a check will be done for
3382 permitted hosts. */
3383
3384 case HELP_CMD:
3385 smtp_printf("214-Commands supported:\r\n");
3386 {
3387 uschar buffer[256];
3388 buffer[0] = 0;
3389 Ustrcat(buffer, " AUTH");
3390 #ifdef SUPPORT_TLS
3391 Ustrcat(buffer, " STARTTLS");
3392 #endif
3393 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3394 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3395 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3396 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3397 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3398 smtp_printf("214%s\r\n", buffer);
3399 }
3400 break;
3401
3402
3403 case EOF_CMD:
3404 incomplete_transaction_log(US"connection lost");
3405 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3406
3407 /* Don't log by default unless in the middle of a message, as some mailers
3408 just drop the call rather than sending QUIT, and it clutters up the logs.
3409 */
3410
3411 if (sender_address != NULL || recipients_count > 0)
3412 log_write(L_lost_incoming_connection,
3413 LOG_MAIN,
3414 "unexpected %s while reading SMTP command from %s%s",
3415 sender_host_unknown? "EOF" : "disconnection",
3416 host_and_ident(FALSE), smtp_read_error);
3417
3418 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3419 smtp_get_connection_info(), smtp_read_error);
3420
3421 done = 1;
3422 break;
3423
3424
3425 case ETRN_CMD:
3426 if (sender_address != NULL)
3427 {
3428 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3429 US"ETRN is not permitted inside a transaction");
3430 break;
3431 }
3432
64ffc24f 3433 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_command_argument,
059ec3d9
PH
3434 host_and_ident(FALSE));
3435
64ffc24f 3436 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
059ec3d9
PH
3437 if (rc != OK)
3438 {
3439 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3440 break;
3441 }
3442
3443 /* Compute the serialization key for this command. */
3444
64ffc24f 3445 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_command_argument);
059ec3d9
PH
3446
3447 /* If a command has been specified for running as a result of ETRN, we
3448 permit any argument to ETRN. If not, only the # standard form is permitted,
3449 since that is strictly the only kind of ETRN that can be implemented
3450 according to the RFC. */
3451
3452 if (smtp_etrn_command != NULL)
3453 {
3454 uschar *error;
3455 BOOL rc;
3456 etrn_command = smtp_etrn_command;
64ffc24f 3457 deliver_domain = smtp_command_argument;
059ec3d9
PH
3458 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3459 US"ETRN processing", &error);
3460 deliver_domain = NULL;
3461 if (!rc)
3462 {
3463 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3464 error);
3465 smtp_printf("458 Internal failure\r\n");
3466 break;
3467 }
3468 }
3469
3470 /* Else set up to call Exim with the -R option. */
3471
3472 else
3473 {
64ffc24f 3474 if (*smtp_command_argument++ != '#')
059ec3d9
PH
3475 {
3476 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3477 US"argument must begin with #");
3478 break;
3479 }
3480 etrn_command = US"exim -R";
3481 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
64ffc24f 3482 smtp_command_argument);
059ec3d9
PH
3483 }
3484
3485 /* If we are host-testing, don't actually do anything. */
3486
3487 if (host_checking)
3488 {
3489 HDEBUG(D_any)
3490 {
3491 debug_printf("ETRN command is: %s\n", etrn_command);
3492 debug_printf("ETRN command execution skipped\n");
3493 }
3494 smtp_printf("250 OK\r\n");
3495 break;
3496 }
3497
3498
3499 /* If ETRN queue runs are to be serialized, check the database to
3500 ensure one isn't already running. */
3501
3502 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3503 {
64ffc24f 3504 smtp_printf("458 Already processing %s\r\n", smtp_command_argument);
059ec3d9
PH
3505 break;
3506 }
3507
3508 /* Fork a child process and run the command. We don't want to have to
3509 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3510 forking. It should be set that way anyway for external incoming SMTP,
3511 but we save and restore to be tidy. If serialization is required, we
3512 actually run the command in yet another process, so we can wait for it
3513 to complete and then remove the serialization lock. */
3514
3515 oldsignal = signal(SIGCHLD, SIG_IGN);
3516
3517 if ((pid = fork()) == 0)
3518 {
f1e894f3
PH
3519 smtp_input = FALSE; /* This process is not associated with the */
3520 (void)fclose(smtp_in); /* SMTP call any more. */
3521 (void)fclose(smtp_out);
059ec3d9
PH
3522
3523 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3524
3525 /* If not serializing, do the exec right away. Otherwise, fork down
3526 into another process. */
3527
3528 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3529 {
3530 DEBUG(D_exec) debug_print_argv(argv);
3531 exim_nullstd(); /* Ensure std{in,out,err} exist */
3532 execv(CS argv[0], (char *const *)argv);
3533 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3534 etrn_command, strerror(errno));
3535 _exit(EXIT_FAILURE); /* paranoia */
3536 }
3537
3538 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3539 is, we are in the first subprocess, after forking again. All we can do
3540 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3541 complete, before removing the serialization. */
3542
3543 if (pid < 0)
3544 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3545 "failed: %s", strerror(errno));
3546 else
3547 {
3548 int status;
3549 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3550 (int)pid);
3551 (void)wait(&status);
3552 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3553 (int)pid);
3554 }
3555
3556 enq_end(etrn_serialize_key);
3557 _exit(EXIT_SUCCESS);
3558 }
3559
3560 /* Back in the top level SMTP process. Check that we started a subprocess
3561 and restore the signal state. */
3562
3563 if (pid < 0)
3564 {
3565 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3566 strerror(errno));
3567 smtp_printf("458 Unable to fork process\r\n");
3568 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3569 }
3570 else smtp_printf("250 OK\r\n");
3571
3572 signal(SIGCHLD, oldsignal);
3573 break;
3574
3575
3576 case BADARG_CMD:
3577 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3578 US"unexpected argument data");
3579 break;
3580
3581
3582 /* This currently happens only for NULLs, but could be extended. */
3583
3584 case BADCHAR_CMD:
3585 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3586 US"NULL character(s) present (shown as '?')");
3587 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3588 break;
3589
3590
3591 case BADSYN_CMD:
3592 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3593 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3594 c = smtp_inend - smtp_inptr;
3595 if (c > 150) c = 150;
3596 smtp_inptr[c] = 0;
3597 incomplete_transaction_log(US"sync failure");
3af76a81 3598 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
059ec3d9
PH
3599 "(next input sent too soon: pipelining was%s advertised): "
3600 "rejected \"%s\" %s next input=\"%s\"",
3601 pipelining_advertised? "" : " not",
3602 cmd_buffer, host_and_ident(TRUE),
3603 string_printing(smtp_inptr));
3604 smtp_printf("554 SMTP synchronization error\r\n");
3605 done = 1; /* Pretend eof - drops connection */
3606 break;
3607
3608
3609 case TOO_MANY_NONMAIL_CMD:
3610 incomplete_transaction_log(US"too many non-mail commands");
3611 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3612 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
64ffc24f 3613 smtp_command_argument - cmd_buffer, cmd_buffer);
059ec3d9
PH
3614 smtp_printf("554 Too many nonmail commands\r\n");
3615 done = 1; /* Pretend eof - drops connection */
3616 break;
3617
3618
3619 default:
3620 if (unknown_command_count++ >= smtp_max_unknown_commands)
3621 {
3622 log_write(L_smtp_syntax_error, LOG_MAIN,
3623 "SMTP syntax error in \"%s\" %s %s",
3624 string_printing(cmd_buffer), host_and_ident(TRUE),
3625 US"unrecognized command");
3626 incomplete_transaction_log(US"unrecognized command");
3627 smtp_printf("500 Too many unrecognized commands\r\n");
3628 done = 2;
3629 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3630 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3631 cmd_buffer);
3632 }
3633 else
3634 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3635 US"unrecognized command");
3636 break;
3637 }
3638
3639 /* This label is used by goto's inside loops that want to break out to
3640 the end of the command-processing loop. */
3641
3642 COMMAND_LOOP:
3643 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3644 last_was_rcpt = was_rcpt; /* protocol error handling */
3645 continue;
3646 }
3647
3648return done - 2; /* Convert yield values */
3649}
3650
3651/* End of smtp_in.c */