1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.63.2.2 2009/04/09 13:57:21 tom Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2007 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. */
42 #define smtp_cmd_buffer_size 2048
44 /* Size of buffer for reading SMTP incoming packets */
46 #define in_buffer_size 8192
48 /* Structure for SMTP command list */
55 short int is_mail_cmd;
58 /* Codes for identifying commands. We order them so that those that come first
59 are those for which synchronization is always required. Checking this can help
63 /* These commands are required to be synchronized, i.e. to be the last in a
64 block of commands when pipelining. */
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 */
71 /* This is a dummy to identify the non-sync commands when pipelining */
73 NON_SYNC_CMD_PIPELINING,
75 /* These commands need not be synchronized when pipelining */
77 MAIL_CMD, RCPT_CMD, RSET_CMD,
79 /* This is a dummy to identify the non-sync commands when not pipelining */
81 NON_SYNC_CMD_NON_PIPELINING,
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. */
89 /* I'm not sure about these, but I don't think they matter. */
93 /* These are specials that don't correspond to actual commands */
95 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
96 TOO_MANY_NONMAIL_CMD };
99 /* This is a convenience macro for adding the identity of an SMTP command
100 to the circular buffer that holds a list of the last n received. */
103 smtp_connection_had[smtp_ch_index++] = n; \
104 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
107 /*************************************************
108 * Local static variables *
109 *************************************************/
111 static auth_instance *authenticated_by;
112 static BOOL auth_advertised;
114 static BOOL tls_advertised;
117 static BOOL helo_required = FALSE;
118 static BOOL helo_verify = FALSE;
119 static BOOL helo_seen;
120 static BOOL helo_accept_junk;
121 static BOOL count_nonmail;
122 static BOOL pipelining_advertised;
123 static BOOL rcpt_smtp_response_same;
124 static BOOL rcpt_in_progress;
125 static int nonmail_command_count;
126 static BOOL smtp_exit_function_called = 0;
127 static int synprot_error_count;
128 static int unknown_command_count;
129 static int sync_cmd_limit;
130 static int smtp_write_error = 0;
132 static uschar *rcpt_smtp_response;
133 static uschar *smtp_data_buffer;
134 static uschar *smtp_cmd_data;
136 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
137 final fields of all except AUTH are forced TRUE at the start of a new message
138 setup, to allow one of each between messages that is not counted as a nonmail
139 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
140 allow a new EHLO after starting up TLS.
142 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
143 counted. However, the flag is changed when AUTH is received, so that multiple
144 failing AUTHs will eventually hit the limit. After a successful AUTH, another
145 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
146 forced TRUE, to allow for the re-authentication that can happen at that point.
148 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
149 count of non-mail commands and possibly provoke an error. */
151 static smtp_cmd_list cmd_list[] = {
152 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
153 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
154 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
155 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
157 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
160 /* If you change anything above here, also fix the definitions below. */
162 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
163 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
164 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
165 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
166 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
167 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
168 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
169 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
170 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
173 static smtp_cmd_list *cmd_list_end =
174 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
176 #define CMD_LIST_RSET 0
177 #define CMD_LIST_HELO 1
178 #define CMD_LIST_EHLO 2
179 #define CMD_LIST_AUTH 3
180 #define CMD_LIST_STARTTLS 4
182 /* This list of names is used for performing the smtp_no_mail logging action.
183 It must be kept in step with the SCH_xxx enumerations. */
185 static uschar *smtp_names[] =
187 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
188 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
191 static uschar *protocols[] = {
192 US"local-smtp", /* HELO */
193 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
194 US"local-esmtp", /* EHLO */
195 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
196 US"local-esmtpa", /* EHLO->AUTH */
197 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
202 #define pcrpted 1 /* added to pextend or pnormal */
203 #define pauthed 2 /* added to pextend */
204 #define pnlocal 6 /* offset to remove "local" */
206 /* When reading SMTP from a remote host, we have to use our own versions of the
207 C input-reading functions, in order to be able to flush the SMTP output only
208 when about to read more data from the socket. This is the only way to get
209 optimal performance when the client is using pipelining. Flushing for every
210 command causes a separate packet and reply packet each time; saving all the
211 responses up (when pipelining) combines them into one packet and one response.
213 For simplicity, these functions are used for *all* SMTP input, not only when
214 receiving over a socket. However, after setting up a secure socket (SSL), input
215 is read via the OpenSSL library, and another set of functions is used instead
218 These functions are set in the receive_getc etc. variables and called with the
219 same interface as the C functions. However, since there can only ever be
220 one incoming SMTP call, we just use a single buffer and flags. There is no need
221 to implement a complicated private FILE-like structure.*/
223 static uschar *smtp_inbuffer;
224 static uschar *smtp_inptr;
225 static uschar *smtp_inend;
226 static int smtp_had_eof;
227 static int smtp_had_error;
230 /*************************************************
231 * SMTP version of getc() *
232 *************************************************/
234 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
235 it flushes the output, and refills the buffer, with a timeout. The signal
236 handler is set appropriately by the calling function. This function is not used
237 after a connection has negotated itself into an TLS/SSL state.
240 Returns: the next character or EOF
246 if (smtp_inptr >= smtp_inend)
250 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
251 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
256 /* Must put the error text in fixed store, because this might be during
257 header reading, where it releases unused store above the header. */
260 smtp_had_error = save_errno;
261 smtp_read_error = string_copy_malloc(
262 string_sprintf(" (error: %s)", strerror(save_errno)));
264 else smtp_had_eof = 1;
268 if (dkim_collect_input) dkim_collect_input = dkim_exim_verify_feed(smtp_inbuffer, rc);
270 smtp_inend = smtp_inbuffer + rc;
271 smtp_inptr = smtp_inbuffer;
273 return *smtp_inptr++;
278 /*************************************************
279 * SMTP version of ungetc() *
280 *************************************************/
282 /* Puts a character back in the input buffer. Only ever
288 Returns: the character
294 *(--smtp_inptr) = ch;
301 /*************************************************
302 * SMTP version of feof() *
303 *************************************************/
305 /* Tests for a previous EOF
308 Returns: non-zero if the eof flag is set
320 /*************************************************
321 * SMTP version of ferror() *
322 *************************************************/
324 /* Tests for a previous read error, and returns with errno
325 restored to what it was when the error was detected.
328 Returns: non-zero if the error flag is set
334 errno = smtp_had_error;
335 return smtp_had_error;
340 /*************************************************
341 * Test for characters in the SMTP buffer *
342 *************************************************/
344 /* Used at the end of a message
353 return smtp_inptr < smtp_inend;
358 /*************************************************
359 * Write formatted string to SMTP channel *
360 *************************************************/
362 /* This is a separate function so that we don't have to repeat everything for
363 TLS support or debugging. It is global so that the daemon and the
364 authentication functions can use it. It does not return any error indication,
365 because major problems such as dropped connections won't show up till an output
366 flush for non-TLS connections. The smtp_fflush() function is available for
367 checking that: for convenience, TLS output errors are remembered here so that
368 they are also picked up later by smtp_fflush().
372 ... optional arguments
378 smtp_printf(char *format, ...)
382 va_start(ap, format);
383 smtp_vprintf(format, ap);
387 /* This is split off so that verify.c:respond_printf() can, in effect, call
388 smtp_printf(), bearing in mind that in C a vararg function can't directly
389 call another vararg function, only a function which accepts a va_list.
391 Note also that repeated calls to va_start()/va_end() pairs is claimed to be
392 non-portable; meanwhile, va_copy() is also non-portable in that it's C99, so
393 we end up needing OS support to define it for us. */
396 smtp_vprintf(char *format, va_list ap)
404 (void) string_vformat(big_buffer, big_buffer_size, format, ap_d);
405 end = big_buffer + Ustrlen(big_buffer);
406 while ((cr = Ustrchr(big_buffer, '\r')) != NULL) /* lose CRs */
407 memmove(cr, cr + 1, (end--) - cr);
408 debug_printf("SMTP>> %s", big_buffer);
411 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
413 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
414 smtp_closedown(US"Unexpected error");
415 exim_exit(EXIT_FAILURE);
418 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
419 have had the same. Note: this code is also present in smtp_respond(). It would
420 be tidier to have it only in one place, but when it was added, it was easier to
421 do it that way, so as not to have to mess with the code for the RCPT command,
422 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
424 if (rcpt_in_progress)
426 if (rcpt_smtp_response == NULL)
427 rcpt_smtp_response = string_copy(big_buffer);
428 else if (rcpt_smtp_response_same &&
429 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
430 rcpt_smtp_response_same = FALSE;
431 rcpt_in_progress = FALSE;
434 /* Now write the string */
439 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
444 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
449 /*************************************************
450 * Flush SMTP out and check for error *
451 *************************************************/
453 /* This function isn't currently used within Exim (it detects errors when it
454 tries to read the next SMTP input), but is available for use in local_scan().
455 For non-TLS connections, it flushes the output and checks for errors. For
456 TLS-connections, it checks for a previously-detected TLS write error.
459 Returns: 0 for no error; -1 after an error
465 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
466 return smtp_write_error;
471 /*************************************************
472 * SMTP command read timeout *
473 *************************************************/
475 /* Signal handler for timing out incoming SMTP commands. This attempts to
478 Argument: signal number (SIGALRM)
483 command_timeout_handler(int sig)
485 sig = sig; /* Keep picky compilers happy */
486 log_write(L_lost_incoming_connection,
487 LOG_MAIN, "SMTP command timeout on%s connection from %s",
488 (tls_active >= 0)? " TLS" : "",
489 host_and_ident(FALSE));
490 if (smtp_batched_input)
491 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
492 smtp_notquit_exit(US"command-timeout", US"421",
493 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
494 exim_exit(EXIT_FAILURE);
499 /*************************************************
501 *************************************************/
503 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
505 Argument: signal number (SIGTERM)
510 command_sigterm_handler(int sig)
512 sig = sig; /* Keep picky compilers happy */
513 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
514 if (smtp_batched_input)
515 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
516 smtp_notquit_exit(US"signal-exit", US"421",
517 US"%s: Service not available - closing connection", smtp_active_hostname);
518 exim_exit(EXIT_FAILURE);
524 /*************************************************
525 * Read one command line *
526 *************************************************/
528 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
529 There are sites that don't do this, and in any case internal SMTP probably
530 should check only for LF. Consequently, we check here for LF only. The line
531 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
532 an unknown command. The command is read into the global smtp_cmd_buffer so that
533 it is available via $smtp_command.
535 The character reading routine sets up a timeout for each block actually read
536 from the input (which may contain more than one command). We set up a special
537 signal handler that closes down the session on a timeout. Control does not
541 check_sync if TRUE, check synchronization rules if global option is TRUE
543 Returns: a code identifying the command (enumerated above)
547 smtp_read_command(BOOL check_sync)
552 BOOL hadnull = FALSE;
554 os_non_restarting_signal(SIGALRM, command_timeout_handler);
556 while ((c = (receive_getc)()) != '\n' && c != EOF)
558 if (ptr >= smtp_cmd_buffer_size)
560 os_non_restarting_signal(SIGALRM, sigalrm_handler);
568 smtp_cmd_buffer[ptr++] = c;
571 receive_linecount++; /* For BSMTP errors */
572 os_non_restarting_signal(SIGALRM, sigalrm_handler);
574 /* If hit end of file, return pseudo EOF command. Whether we have a
575 part-line already read doesn't matter, since this is an error state. */
577 if (c == EOF) return EOF_CMD;
579 /* Remove any CR and white space at the end of the line, and terminate the
582 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
583 smtp_cmd_buffer[ptr] = 0;
585 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
587 /* NULLs are not allowed in SMTP commands */
589 if (hadnull) return BADCHAR_CMD;
591 /* Scan command list and return identity, having set the data pointer
592 to the start of the actual data characters. Check for SMTP synchronization
595 for (p = cmd_list; p < cmd_list_end; p++)
597 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
598 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
599 smtp_cmd_buffer[p->len] == 0 ||
600 smtp_cmd_buffer[p->len] == ' '))
602 if (smtp_inptr < smtp_inend && /* Outstanding input */
603 p->cmd < sync_cmd_limit && /* Command should sync */
604 check_sync && /* Local flag set */
605 smtp_enforce_sync && /* Global flag set */
606 sender_host_address != NULL && /* Not local input */
607 !sender_host_notsocket) /* Really is a socket */
610 /* The variables $smtp_command and $smtp_command_argument point into the
611 unmodified input buffer. A copy of the latter is taken for actual
612 processing, so that it can be chopped up into separate parts if necessary,
613 for example, when processing a MAIL command options such as SIZE that can
614 follow the sender address. */
616 smtp_cmd_argument = smtp_cmd_buffer + p->len;
617 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
618 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
619 smtp_cmd_data = smtp_data_buffer;
621 /* Count non-mail commands from those hosts that are controlled in this
622 way. The default is all hosts. We don't waste effort checking the list
623 until we get a non-mail command, but then cache the result to save checking
624 again. If there's a DEFER while checking the host, assume it's in the list.
626 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
627 start of each incoming message by fiddling with the value in the table. */
631 if (count_nonmail == TRUE_UNSET) count_nonmail =
632 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
633 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
634 return TOO_MANY_NONMAIL_CMD;
637 /* If there is data for a command that does not expect it, generate the
640 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
644 /* Enforce synchronization for unknown commands */
646 if (smtp_inptr < smtp_inend && /* Outstanding input */
647 check_sync && /* Local flag set */
648 smtp_enforce_sync && /* Global flag set */
649 sender_host_address != NULL && /* Not local input */
650 !sender_host_notsocket) /* Really is a socket */
658 /*************************************************
659 * Recheck synchronization *
660 *************************************************/
662 /* Synchronization checks can never be perfect because a packet may be on its
663 way but not arrived when the check is done. Such checks can in any case only be
664 done when TLS is not in use. Normally, the checks happen when commands are
665 read: Exim ensures that there is no more input in the input buffer. In normal
666 cases, the response to the command will be fast, and there is no further check.
668 However, for some commands an ACL is run, and that can include delays. In those
669 cases, it is useful to do another check on the input just before sending the
670 response. This also applies at the start of a connection. This function does
671 that check by means of the select() function, as long as the facility is not
672 disabled or inappropriate. A failure of select() is ignored.
674 When there is unwanted input, we read it so that it appears in the log of the
678 Returns: TRUE if all is well; FALSE if there is input pending
686 struct timeval tzero;
688 if (!smtp_enforce_sync || sender_host_address == NULL ||
689 sender_host_notsocket || tls_active >= 0)
692 fd = fileno(smtp_in);
697 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
699 if (rc <= 0) return TRUE; /* Not ready to read */
701 if (rc < 0) return TRUE; /* End of file or error */
704 rc = smtp_inend - smtp_inptr;
705 if (rc > 150) rc = 150;
712 /*************************************************
713 * Forced closedown of call *
714 *************************************************/
716 /* This function is called from log.c when Exim is dying because of a serious
717 disaster, and also from some other places. If an incoming non-batched SMTP
718 channel is open, it swallows the rest of the incoming message if in the DATA
719 phase, sends the reply string, and gives an error to all subsequent commands
720 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
724 message SMTP reply string to send, excluding the code
730 smtp_closedown(uschar *message)
732 if (smtp_in == NULL || smtp_batched_input) return;
733 receive_swallow_smtp();
734 smtp_printf("421 %s\r\n", message);
738 switch(smtp_read_command(FALSE))
744 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
749 smtp_printf("250 Reset OK\r\n");
753 smtp_printf("421 %s\r\n", message);
762 /*************************************************
763 * Set up connection info for logging *
764 *************************************************/
766 /* This function is called when logging information about an SMTP connection.
767 It sets up appropriate source information, depending on the type of connection.
768 If sender_fullhost is NULL, we are at a very early stage of the connection;
769 just use the IP address.
772 Returns: a string describing the connection
776 smtp_get_connection_info(void)
778 uschar *hostname = (sender_fullhost == NULL)?
779 sender_host_address : sender_fullhost;
782 return string_sprintf("SMTP connection from %s", hostname);
784 if (sender_host_unknown || sender_host_notsocket)
785 return string_sprintf("SMTP connection from %s", sender_ident);
788 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
790 if ((log_extra_selector & LX_incoming_interface) != 0 &&
791 interface_address != NULL)
792 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
793 interface_address, interface_port);
795 return string_sprintf("SMTP connection from %s", hostname);
800 /*************************************************
801 * Log lack of MAIL if so configured *
802 *************************************************/
804 /* This function is called when an SMTP session ends. If the log selector
805 smtp_no_mail is set, write a log line giving some details of what has happened
813 smtp_log_no_mail(void)
818 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
824 if (sender_host_authenticated != NULL)
826 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
827 if (authenticated_id != NULL)
828 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
832 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_cipher != NULL)
833 s = string_append(s, &size, &ptr, 2, US" X=", tls_cipher);
834 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
836 s = string_append(s, &size, &ptr, 2, US" CV=",
837 tls_certificate_verified? "yes":"no");
838 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_peerdn != NULL)
839 s = string_append(s, &size, &ptr, 3, US" DN=\"",
840 string_printing(tls_peerdn), US"\"");
843 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
844 US" C=..." : US" C=";
845 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
847 if (smtp_connection_had[i] != SCH_NONE)
849 s = string_append(s, &size, &ptr, 2, sep,
850 smtp_names[smtp_connection_had[i]]);
855 for (i = 0; i < smtp_ch_index; i++)
857 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
861 if (s != NULL) s[ptr] = 0; else s = US"";
862 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
863 host_and_ident(FALSE),
864 readconf_printtime(time(NULL) - smtp_connection_start), s);
869 /*************************************************
870 * Check HELO line and set sender_helo_name *
871 *************************************************/
873 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
874 the domain name of the sending host, or an ip literal in square brackets. The
875 arrgument is placed in sender_helo_name, which is in malloc store, because it
876 must persist over multiple incoming messages. If helo_accept_junk is set, this
877 host is permitted to send any old junk (needed for some broken hosts).
878 Otherwise, helo_allow_chars can be used for rogue characters in general
879 (typically people want to let in underscores).
882 s the data portion of the line (already past any white space)
884 Returns: TRUE or FALSE
888 check_helo(uschar *s)
891 uschar *end = s + Ustrlen(s);
892 BOOL yield = helo_accept_junk;
894 /* Discard any previous helo name */
896 if (sender_helo_name != NULL)
898 store_free(sender_helo_name);
899 sender_helo_name = NULL;
902 /* Skip tests if junk is permitted. */
906 /* Allow the new standard form for IPv6 address literals, namely,
907 [IPv6:....], and because someone is bound to use it, allow an equivalent
908 IPv4 form. Allow plain addresses as well. */
915 if (strncmpic(s, US"[IPv6:", 6) == 0)
916 yield = (string_is_ip_address(s+6, NULL) == 6);
917 else if (strncmpic(s, US"[IPv4:", 6) == 0)
918 yield = (string_is_ip_address(s+6, NULL) == 4);
920 yield = (string_is_ip_address(s+1, NULL) != 0);
925 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
926 that have been configured (usually underscore - sigh). */
933 if (!isalnum(*s) && *s != '.' && *s != '-' &&
934 Ustrchr(helo_allow_chars, *s) == NULL)
944 /* Save argument if OK */
946 if (yield) sender_helo_name = string_copy_malloc(start);
954 /*************************************************
955 * Extract SMTP command option *
956 *************************************************/
958 /* This function picks the next option setting off the end of smtp_cmd_data. It
959 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
960 things that can appear there.
963 name point this at the name
964 value point this at the data string
966 Returns: TRUE if found an option
970 extract_option(uschar **name, uschar **value)
973 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
974 while (isspace(*v)) v--;
977 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
978 if (*v != '=') return FALSE;
981 while(isalpha(n[-1])) n--;
983 if (n[-1] != ' ') return FALSE;
996 /*************************************************
997 * Reset for new message *
998 *************************************************/
1000 /* This function is called whenever the SMTP session is reset from
1001 within either of the setup functions.
1003 Argument: the stacking pool storage reset point
1008 smtp_reset(void *reset_point)
1010 store_reset(reset_point);
1011 recipients_list = NULL;
1012 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1013 raw_recipients_count = recipients_count = recipients_list_max = 0;
1014 message_linecount = 0;
1016 acl_added_headers = NULL;
1017 queue_only_policy = FALSE;
1018 rcpt_smtp_response = NULL;
1019 rcpt_smtp_response_same = TRUE;
1020 rcpt_in_progress = FALSE;
1021 deliver_freeze = FALSE; /* Can be set by ACL */
1022 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1023 fake_response = OK; /* Can be set by ACL */
1024 #ifdef WITH_CONTENT_SCAN
1025 no_mbox_unspool = FALSE; /* Can be set by ACL */
1027 submission_mode = FALSE; /* Can be set by ACL */
1028 suppress_local_fixups = FALSE; /* Can be set by ACL */
1029 active_local_from_check = local_from_check; /* Can be set by ACL */
1030 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1031 sender_address = NULL;
1032 submission_name = NULL; /* Can be set by ACL */
1033 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1034 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1035 sender_verified_list = NULL; /* No senders verified */
1036 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1037 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1038 authenticated_sender = NULL;
1039 #ifdef EXPERIMENTAL_BRIGHTMAIL
1041 bmi_verdicts = NULL;
1043 #ifndef DISABLE_DKIM
1045 dkim_collect_input = 0;
1047 #ifdef EXPERIMENTAL_SPF
1048 spf_header_comment = NULL;
1049 spf_received = NULL;
1051 spf_smtp_comment = NULL;
1053 body_linecount = body_zerocount = 0;
1055 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1056 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1057 /* Note that ratelimiters_conn persists across resets. */
1059 /* Reset message ACL variables */
1063 /* The message body variables use malloc store. They may be set if this is
1064 not the first message in an SMTP session and the previous message caused them
1065 to be referenced in an ACL. */
1067 if (message_body != NULL)
1069 store_free(message_body);
1070 message_body = NULL;
1073 if (message_body_end != NULL)
1075 store_free(message_body_end);
1076 message_body_end = NULL;
1079 /* Warning log messages are also saved in malloc store. They are saved to avoid
1080 repetition in the same message, but it seems right to repeat them for different
1083 while (acl_warn_logged != NULL)
1085 string_item *this = acl_warn_logged;
1086 acl_warn_logged = acl_warn_logged->next;
1095 /*************************************************
1096 * Initialize for incoming batched SMTP message *
1097 *************************************************/
1099 /* This function is called from smtp_setup_msg() in the case when
1100 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1101 of messages in one file with SMTP commands between them. All errors must be
1102 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1103 relevant. After an error on a sender, or an invalid recipient, the remainder
1104 of the message is skipped. The value of received_protocol is already set.
1107 Returns: > 0 message successfully started (reached DATA)
1108 = 0 QUIT read or end of file reached
1109 < 0 should not occur
1113 smtp_setup_batch_msg(void)
1116 void *reset_point = store_get(0);
1118 /* Save the line count at the start of each transaction - single commands
1119 like HELO and RSET count as whole transactions. */
1121 bsmtp_transaction_linecount = receive_linecount;
1123 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1125 smtp_reset(reset_point); /* Reset for start of message */
1127 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1128 value. The values are 2 larger than the required yield of the function. */
1133 uschar *recipient = NULL;
1134 int start, end, sender_domain, recipient_domain;
1136 switch(smtp_read_command(FALSE))
1138 /* The HELO/EHLO commands set sender_address_helo if they have
1139 valid data; otherwise they are ignored, except that they do
1140 a reset of the state. */
1145 check_helo(smtp_cmd_data);
1149 smtp_reset(reset_point);
1150 bsmtp_transaction_linecount = receive_linecount;
1154 /* The MAIL FROM command requires an address as an operand. All we
1155 do here is to parse it for syntactic correctness. The form "<>" is
1156 a special case which converts into an empty string. The start/end
1157 pointers in the original are not used further for this address, as
1158 it is the canonical extracted address which is all that is kept. */
1161 if (sender_address != NULL)
1162 /* The function moan_smtp_batch() does not return. */
1163 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1165 if (smtp_cmd_data[0] == 0)
1166 /* The function moan_smtp_batch() does not return. */
1167 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1169 /* Reset to start of message */
1171 smtp_reset(reset_point);
1173 /* Apply SMTP rewrite */
1175 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1176 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1177 US"", global_rewrite_rules) : smtp_cmd_data;
1179 /* Extract the address; the TRUE flag allows <> as valid */
1182 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1185 if (raw_sender == NULL)
1186 /* The function moan_smtp_batch() does not return. */
1187 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1189 sender_address = string_copy(raw_sender);
1191 /* Qualify unqualified sender addresses if permitted to do so. */
1193 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1195 if (allow_unqualified_sender)
1197 sender_address = rewrite_address_qualify(sender_address, FALSE);
1198 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1199 "and rewritten\n", raw_sender);
1201 /* The function moan_smtp_batch() does not return. */
1202 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1208 /* The RCPT TO command requires an address as an operand. All we do
1209 here is to parse it for syntactic correctness. There may be any number
1210 of RCPT TO commands, specifying multiple senders. We build them all into
1211 a data structure that is in argc/argv format. The start/end values
1212 given by parse_extract_address are not used, as we keep only the
1213 extracted address. */
1216 if (sender_address == NULL)
1217 /* The function moan_smtp_batch() does not return. */
1218 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1220 if (smtp_cmd_data[0] == 0)
1221 /* The function moan_smtp_batch() does not return. */
1222 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1224 /* Check maximum number allowed */
1226 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1227 /* The function moan_smtp_batch() does not return. */
1228 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1229 recipients_max_reject? "552": "452");
1231 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1232 recipient address */
1234 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1235 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1236 global_rewrite_rules) : smtp_cmd_data;
1238 /* rfc821_domains = TRUE; << no longer needed */
1239 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1240 &recipient_domain, FALSE);
1241 /* rfc821_domains = FALSE; << no longer needed */
1243 if (recipient == NULL)
1244 /* The function moan_smtp_batch() does not return. */
1245 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1247 /* If the recipient address is unqualified, qualify it if permitted. Then
1248 add it to the list of recipients. */
1250 if (recipient_domain == 0)
1252 if (allow_unqualified_recipient)
1254 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1256 recipient = rewrite_address_qualify(recipient, TRUE);
1258 /* The function moan_smtp_batch() does not return. */
1259 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1262 receive_add_recipient(recipient, -1);
1266 /* The DATA command is legal only if it follows successful MAIL FROM
1267 and RCPT TO commands. This function is complete when a valid DATA
1268 command is encountered. */
1271 if (sender_address == NULL || recipients_count <= 0)
1273 /* The function moan_smtp_batch() does not return. */
1274 if (sender_address == NULL)
1275 moan_smtp_batch(smtp_cmd_buffer,
1276 "503 MAIL FROM:<sender> command must precede DATA");
1278 moan_smtp_batch(smtp_cmd_buffer,
1279 "503 RCPT TO:<recipient> must precede DATA");
1283 done = 3; /* DATA successfully achieved */
1284 message_ended = END_NOTENDED; /* Indicate in middle of message */
1289 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1296 bsmtp_transaction_linecount = receive_linecount;
1307 /* The function moan_smtp_batch() does not return. */
1308 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1313 /* The function moan_smtp_batch() does not return. */
1314 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1319 /* The function moan_smtp_batch() does not return. */
1320 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1325 return done - 2; /* Convert yield values */
1331 /*************************************************
1332 * Start an SMTP session *
1333 *************************************************/
1335 /* This function is called at the start of an SMTP session. Thereafter,
1336 smtp_setup_msg() is called to initiate each separate message. This
1337 function does host-specific testing, and outputs the banner line.
1340 Returns: FALSE if the session can not continue; something has
1341 gone wrong, or the connection to the host is blocked
1345 smtp_start_session(void)
1349 uschar *user_msg, *log_msg;
1353 smtp_connection_start = time(NULL);
1354 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1355 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1358 /* Default values for certain variables */
1360 helo_seen = esmtp = helo_accept_junk = FALSE;
1361 smtp_mailcmd_count = 0;
1362 count_nonmail = TRUE_UNSET;
1363 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1364 smtp_delay_mail = smtp_rlm_base;
1365 auth_advertised = FALSE;
1366 pipelining_advertised = FALSE;
1367 pipelining_enable = TRUE;
1368 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1369 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1371 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1373 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1374 authentication settings from -oMaa to remain in force. */
1376 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1377 authenticated_by = NULL;
1380 tls_cipher = tls_peerdn = NULL;
1381 tls_advertised = FALSE;
1384 /* Reset ACL connection variables */
1388 /* Allow for trailing 0 in the command and data buffers. */
1390 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1391 if (smtp_cmd_buffer == NULL)
1392 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1393 "malloc() failed for SMTP command buffer");
1394 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1396 /* For batched input, the protocol setting can be overridden from the
1397 command line by a trusted caller. */
1399 if (smtp_batched_input)
1401 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1404 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1405 reset later if any of EHLO/AUTH/STARTTLS are received. */
1409 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1411 /* Set up the buffer for inputting using direct read() calls, and arrange to
1412 call the local functions instead of the standard C ones. */
1414 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1415 if (smtp_inbuffer == NULL)
1416 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1417 receive_getc = smtp_getc;
1418 receive_ungetc = smtp_ungetc;
1419 receive_feof = smtp_feof;
1420 receive_ferror = smtp_ferror;
1421 receive_smtp_buffered = smtp_buffered;
1422 smtp_inptr = smtp_inend = smtp_inbuffer;
1423 smtp_had_eof = smtp_had_error = 0;
1425 /* Set up the message size limit; this may be host-specific */
1427 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1428 if (expand_string_message != NULL)
1430 if (thismessage_size_limit == -1)
1431 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1432 "%s", expand_string_message);
1434 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1435 "%s", expand_string_message);
1436 smtp_closedown(US"Temporary local problem - please try later");
1440 /* When a message is input locally via the -bs or -bS options, sender_host_
1441 unknown is set unless -oMa was used to force an IP address, in which case it
1442 is checked like a real remote connection. When -bs is used from inetd, this
1443 flag is not set, causing the sending host to be checked. The code that deals
1444 with IP source routing (if configured) is never required for -bs or -bS and
1445 the flag sender_host_notsocket is used to suppress it.
1447 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1448 reserve for certain hosts and/or networks. */
1450 if (!sender_host_unknown)
1453 BOOL reserved_host = FALSE;
1455 /* Look up IP options (source routing info) on the socket if this is not an
1456 -oMa "host", and if any are found, log them and drop the connection.
1458 Linux (and others now, see below) is different to everyone else, so there
1459 has to be some conditional compilation here. Versions of Linux before 2.1.15
1460 used a structure whose name was "options". Somebody finally realized that
1461 this name was silly, and it got changed to "ip_options". I use the
1462 newer name here, but there is a fudge in the script that sets up os.h
1463 to define a macro in older Linux systems.
1465 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1466 glibc 2, which has chosen ip_opts for the structure name. This is now
1467 really a glibc thing rather than a Linux thing, so the condition name
1468 has been changed to reflect this. It is relevant also to GNU/Hurd.
1470 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1471 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1472 a special macro defined in the os.h file.
1474 Some DGUX versions on older hardware appear not to support IP options at
1475 all, so there is now a general macro which can be set to cut out this
1478 How to do this properly in IPv6 is not yet known. */
1480 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1482 #ifdef GLIBC_IP_OPTIONS
1483 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1488 #elif defined DARWIN_IP_OPTIONS
1494 if (!host_checking && !sender_host_notsocket)
1497 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1498 struct ip_options *ipopt = store_get(optlen);
1500 struct ip_opts ipoptblock;
1501 struct ip_opts *ipopt = &ipoptblock;
1502 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1504 struct ipoption ipoptblock;
1505 struct ipoption *ipopt = &ipoptblock;
1506 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1509 /* Occasional genuine failures of getsockopt() have been seen - for
1510 example, "reset by peer". Therefore, just log and give up on this
1511 call, unless the error is ENOPROTOOPT. This error is given by systems
1512 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1513 of writing. So for that error, carry on - we just can't do an IP options
1516 DEBUG(D_receive) debug_printf("checking for IP options\n");
1518 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1521 if (errno != ENOPROTOOPT)
1523 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1524 host_and_ident(FALSE), strerror(errno));
1525 smtp_printf("451 SMTP service not available\r\n");
1530 /* Deal with any IP options that are set. On the systems I have looked at,
1531 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1532 more logging data than will fit in big_buffer. Nevertheless, after somebody
1533 questioned this code, I've added in some paranoid checking. */
1535 else if (optlen > 0)
1537 uschar *p = big_buffer;
1538 uschar *pend = big_buffer + big_buffer_size;
1539 uschar *opt, *adptr;
1541 struct in_addr addr;
1544 uschar *optstart = (uschar *)(ipopt->__data);
1546 uschar *optstart = (uschar *)(ipopt->ip_opts);
1548 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1551 DEBUG(D_receive) debug_printf("IP options exist\n");
1553 Ustrcpy(p, "IP options on incoming call:");
1556 for (opt = optstart; opt != NULL &&
1557 opt < (uschar *)(ipopt) + optlen;)
1571 if (!string_format(p, pend-p, " %s [@%s",
1572 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1574 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1576 inet_ntoa(ipopt->ip_dst)))
1578 inet_ntoa(ipopt->ipopt_dst)))
1586 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1588 while (optcount-- > 0)
1590 memcpy(&addr, adptr, sizeof(addr));
1591 if (!string_format(p, pend - p - 1, "%s%s",
1592 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1598 adptr += sizeof(struct in_addr);
1607 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1610 for (i = 0; i < opt[1]; i++)
1612 sprintf(CS p, "%2.2x ", opt[i]);
1623 log_write(0, LOG_MAIN, "%s", big_buffer);
1625 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1627 log_write(0, LOG_MAIN|LOG_REJECT,
1628 "connection from %s refused (IP options)", host_and_ident(FALSE));
1630 smtp_printf("554 SMTP service not available\r\n");
1634 /* Length of options = 0 => there are no options */
1636 else DEBUG(D_receive) debug_printf("no IP options found\n");
1638 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1640 /* Set keep-alive in socket options. The option is on by default. This
1641 setting is an attempt to get rid of some hanging connections that stick in
1642 read() when the remote end (usually a dialup) goes away. */
1644 if (smtp_accept_keepalive && !sender_host_notsocket)
1645 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1647 /* If the current host matches host_lookup, set the name by doing a
1648 reverse lookup. On failure, sender_host_name will be NULL and
1649 host_lookup_failed will be TRUE. This may or may not be serious - optional
1652 if (verify_check_host(&host_lookup) == OK)
1654 (void)host_name_lookup();
1655 host_build_sender_fullhost();
1658 /* Delay this until we have the full name, if it is looked up. */
1660 set_process_info("handling incoming connection from %s",
1661 host_and_ident(FALSE));
1663 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1664 smtps port for use with older style SSL MTAs. */
1667 if (tls_on_connect &&
1668 tls_server_start(tls_require_ciphers,
1669 gnutls_require_mac, gnutls_require_kx, gnutls_require_proto) != OK)
1673 /* Test for explicit connection rejection */
1675 if (verify_check_host(&host_reject_connection) == OK)
1677 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1678 "from %s (host_reject_connection)", host_and_ident(FALSE));
1679 smtp_printf("554 SMTP service not available\r\n");
1683 /* Test with TCP Wrappers if so configured. There is a problem in that
1684 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1685 such as disks dying. In these cases, it is desirable to reject with a 4xx
1686 error instead of a 5xx error. There isn't a "right" way to detect such
1687 problems. The following kludge is used: errno is zeroed before calling
1688 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1689 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1692 #ifdef USE_TCP_WRAPPERS
1694 if (!hosts_ctl("exim",
1695 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1696 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1697 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1699 if (errno == 0 || errno == ENOENT)
1701 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1702 log_write(L_connection_reject,
1703 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1704 "(tcp wrappers)", host_and_ident(FALSE));
1705 smtp_printf("554 SMTP service not available\r\n");
1709 int save_errno = errno;
1710 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1711 "errno value %d\n", save_errno);
1712 log_write(L_connection_reject,
1713 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1714 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1715 smtp_printf("451 Temporary local problem - please try later\r\n");
1721 /* Check for reserved slots. The value of smtp_accept_count has already been
1722 incremented to include this process. */
1724 if (smtp_accept_max > 0 &&
1725 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
1727 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1729 log_write(L_connection_reject,
1730 LOG_MAIN, "temporarily refused connection from %s: not in "
1731 "reserve list: connected=%d max=%d reserve=%d%s",
1732 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
1733 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1734 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1735 "please try again later\r\n", smtp_active_hostname);
1738 reserved_host = TRUE;
1741 /* If a load level above which only messages from reserved hosts are
1742 accepted is set, check the load. For incoming calls via the daemon, the
1743 check is done in the superior process if there are no reserved hosts, to
1744 save a fork. In all cases, the load average will already be available
1745 in a global variable at this point. */
1747 if (smtp_load_reserve >= 0 &&
1748 load_average > smtp_load_reserve &&
1750 verify_check_host(&smtp_reserve_hosts) != OK)
1752 log_write(L_connection_reject,
1753 LOG_MAIN, "temporarily refused connection from %s: not in "
1754 "reserve list and load average = %.2f", host_and_ident(FALSE),
1755 (double)load_average/1000.0);
1756 smtp_printf("421 %s: Too much load; please try again later\r\n",
1757 smtp_active_hostname);
1761 /* Determine whether unqualified senders or recipients are permitted
1762 for this host. Unfortunately, we have to do this every time, in order to
1763 set the flags so that they can be inspected when considering qualifying
1764 addresses in the headers. For a site that permits no qualification, this
1765 won't take long, however. */
1767 allow_unqualified_sender =
1768 verify_check_host(&sender_unqualified_hosts) == OK;
1770 allow_unqualified_recipient =
1771 verify_check_host(&recipient_unqualified_hosts) == OK;
1773 /* Determine whether HELO/EHLO is required for this host. The requirement
1774 can be hard or soft. */
1776 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1778 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1780 /* Determine whether this hosts is permitted to send syntactic junk
1781 after a HELO or EHLO command. */
1783 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1786 /* For batch SMTP input we are now done. */
1788 if (smtp_batched_input) return TRUE;
1790 /* Run the ACL if it exists */
1793 if (acl_smtp_connect != NULL)
1796 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1800 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1805 /* Output the initial message for a two-way SMTP connection. It may contain
1806 newlines, which then cause a multi-line response to be given. */
1808 code = US"220"; /* Default status code */
1809 esc = US""; /* Default extended status code */
1810 esclen = 0; /* Length of esc */
1812 if (user_msg == NULL)
1814 s = expand_string(smtp_banner);
1816 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1817 "failed: %s", smtp_banner, expand_string_message);
1823 smtp_message_code(&code, &codelen, &s, NULL);
1827 esclen = codelen - 4;
1831 /* Remove any terminating newlines; might as well remove trailing space too */
1834 while (p > s && isspace(p[-1])) p--;
1837 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1838 is all contained in a single IP packet. The original code wrote out the
1839 greeting using several calls to fprint/fputc, and on busy servers this could
1840 cause it to be split over more than one packet - which caused CC:Mail to fall
1841 over when it got the second part of the greeting after sending its first
1842 command. Sigh. To try to avoid this, build the complete greeting message
1843 first, and output it in one fell swoop. This gives a better chance of it
1844 ending up as a single packet. */
1846 ss = store_get(size);
1850 do /* At least once, in case we have an empty string */
1853 uschar *linebreak = Ustrchr(p, '\n');
1854 ss = string_cat(ss, &size, &ptr, code, 3);
1855 if (linebreak == NULL)
1858 ss = string_cat(ss, &size, &ptr, US" ", 1);
1862 len = linebreak - p;
1863 ss = string_cat(ss, &size, &ptr, US"-", 1);
1865 ss = string_cat(ss, &size, &ptr, esc, esclen);
1866 ss = string_cat(ss, &size, &ptr, p, len);
1867 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1869 if (linebreak != NULL) p++;
1873 ss[ptr] = 0; /* string_cat leaves room for this */
1875 /* Before we write the banner, check that there is no input pending, unless
1876 this synchronisation check is disabled. */
1880 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1881 "synchronization error (input sent without waiting for greeting): "
1882 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1883 string_printing(smtp_inptr));
1884 smtp_printf("554 SMTP synchronization error\r\n");
1888 /* Now output the banner */
1890 smtp_printf("%s", ss);
1898 /*************************************************
1899 * Handle SMTP syntax and protocol errors *
1900 *************************************************/
1902 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1903 to do so. Then transmit the error response. The return value depends on the
1904 number of syntax and protocol errors in this SMTP session.
1907 type error type, given as a log flag bit
1908 code response code; <= 0 means don't send a response
1909 data data to reflect in the response (can be NULL)
1910 errmess the error message
1912 Returns: -1 limit of syntax/protocol errors NOT exceeded
1913 +1 limit of syntax/protocol errors IS exceeded
1915 These values fit in with the values of the "done" variable in the main
1916 processing loop in smtp_setup_msg(). */
1919 synprot_error(int type, int code, uschar *data, uschar *errmess)
1923 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1924 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1925 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1927 if (++synprot_error_count > smtp_max_synprot_errors)
1930 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1931 "syntax or protocol errors (last command was \"%s\")",
1932 host_and_ident(FALSE), smtp_cmd_buffer);
1937 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1938 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1940 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1949 /*************************************************
1950 * Log incomplete transactions *
1951 *************************************************/
1953 /* This function is called after a transaction has been aborted by RSET, QUIT,
1954 connection drops or other errors. It logs the envelope information received
1955 so far in order to preserve address verification attempts.
1957 Argument: string to indicate what aborted the transaction
1962 incomplete_transaction_log(uschar *what)
1964 if (sender_address == NULL || /* No transaction in progress */
1965 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1968 /* Build list of recipients for logging */
1970 if (recipients_count > 0)
1973 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1974 for (i = 0; i < recipients_count; i++)
1975 raw_recipients[i] = recipients_list[i].address;
1976 raw_recipients_count = recipients_count;
1979 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1980 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1986 /*************************************************
1987 * Send SMTP response, possibly multiline *
1988 *************************************************/
1990 /* There are, it seems, broken clients out there that cannot handle multiline
1991 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1992 output nothing for non-final calls, and only the first line for anything else.
1995 code SMTP code, may involve extended status codes
1996 codelen length of smtp code; if > 4 there's an ESC
1997 final FALSE if the last line isn't the final line
1998 msg message text, possibly containing newlines
2004 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2009 if (!final && no_multiline_responses) return;
2014 esclen = codelen - 4;
2017 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2018 have had the same. Note: this code is also present in smtp_printf(). It would
2019 be tidier to have it only in one place, but when it was added, it was easier to
2020 do it that way, so as not to have to mess with the code for the RCPT command,
2021 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2023 if (rcpt_in_progress)
2025 if (rcpt_smtp_response == NULL)
2026 rcpt_smtp_response = string_copy(msg);
2027 else if (rcpt_smtp_response_same &&
2028 Ustrcmp(rcpt_smtp_response, msg) != 0)
2029 rcpt_smtp_response_same = FALSE;
2030 rcpt_in_progress = FALSE;
2033 /* Not output the message, splitting it up into multiple lines if necessary. */
2037 uschar *nl = Ustrchr(msg, '\n');
2040 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2043 else if (nl[1] == 0 || no_multiline_responses)
2045 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2046 (int)(nl - msg), msg);
2051 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2053 while (isspace(*msg)) msg++;
2061 /*************************************************
2062 * Parse user SMTP message *
2063 *************************************************/
2065 /* This function allows for user messages overriding the response code details
2066 by providing a suitable response code string at the start of the message
2067 user_msg. Check the message for starting with a response code and optionally an
2068 extended status code. If found, check that the first digit is valid, and if so,
2069 change the code pointer and length to use the replacement. An invalid code
2070 causes a panic log; in this case, if the log messages is the same as the user
2071 message, we must also adjust the value of the log message to show the code that
2072 is actually going to be used (the original one).
2074 This function is global because it is called from receive.c as well as within
2077 Note that the code length returned includes the terminating whitespace
2078 character, which is always included in the regex match.
2081 code SMTP code, may involve extended status codes
2082 codelen length of smtp code; if > 4 there's an ESC
2084 log_msg optional log message, to be adjusted with the new SMTP code
2090 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2095 if (msg == NULL || *msg == NULL) return;
2097 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2098 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2101 if ((*msg)[0] != (*code)[0])
2103 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2104 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2105 if (log_msg != NULL && *log_msg == *msg)
2106 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2111 *codelen = ovector[1]; /* Includes final space */
2113 *msg += ovector[1]; /* Chop the code off the message */
2120 /*************************************************
2121 * Handle an ACL failure *
2122 *************************************************/
2124 /* This function is called when acl_check() fails. As well as calls from within
2125 this module, it is called from receive.c for an ACL after DATA. It sorts out
2126 logging the incident, and sets up the error response. A message containing
2127 newlines is turned into a multiline SMTP response, but for logging, only the
2130 There's a table of default permanent failure response codes to use in
2131 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2132 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2133 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2134 state, because there are broken clients that try VRFY before RCPT. A 5xx
2135 response should be given only when the address is positively known to be
2136 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2139 From Exim 4.63, it is possible to override the response code details by
2140 providing a suitable response code string at the start of the message provided
2141 in user_msg. The code's first digit is checked for validity.
2144 where where the ACL was called from
2146 user_msg a message that can be included in an SMTP response
2147 log_msg a message for logging
2149 Returns: 0 in most cases
2150 2 if the failure code was FAIL_DROP, in which case the
2151 SMTP connection should be dropped (this value fits with the
2152 "done" variable in smtp_setup_msg() below)
2156 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2158 BOOL drop = rc == FAIL_DROP;
2162 uschar *sender_info = US"";
2164 #ifdef WITH_CONTENT_SCAN
2165 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2167 (where == ACL_WHERE_PREDATA)? US"DATA" :
2168 (where == ACL_WHERE_DATA)? US"after DATA" :
2169 (smtp_cmd_data == NULL)?
2170 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2171 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2173 if (drop) rc = FAIL;
2175 /* Set the default SMTP code, and allow a user message to change it. */
2177 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2178 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2180 /* We used to have sender_address here; however, there was a bug that was not
2181 updating sender_address after a rewrite during a verify. When this bug was
2182 fixed, sender_address at this point became the rewritten address. I'm not sure
2183 this is what should be logged, so I've changed to logging the unrewritten
2184 address to retain backward compatibility. */
2186 #ifndef WITH_CONTENT_SCAN
2187 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2189 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2192 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
2193 sender_address_unrewritten : sender_address);
2196 /* If there's been a sender verification failure with a specific message, and
2197 we have not sent a response about it yet, do so now, as a preliminary line for
2198 failures, but not defers. However, always log it for defer, and log it for fail
2199 unless the sender_verify_fail log selector has been turned off. */
2201 if (sender_verified_failed != NULL &&
2202 !testflag(sender_verified_failed, af_sverify_told))
2204 BOOL save_rcpt_in_progress = rcpt_in_progress;
2205 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2207 setflag(sender_verified_failed, af_sverify_told);
2209 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2210 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2211 host_and_ident(TRUE),
2212 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2213 sender_verified_failed->address,
2214 (sender_verified_failed->message == NULL)? US"" :
2215 string_sprintf(": %s", sender_verified_failed->message));
2217 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2218 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2219 testflag(sender_verified_failed, af_verify_pmfail)?
2220 "Postmaster verification failed while checking <%s>\n%s\n"
2221 "Several RFCs state that you are required to have a postmaster\n"
2222 "mailbox for each mail domain. This host does not accept mail\n"
2223 "from domains whose servers reject the postmaster address."
2225 testflag(sender_verified_failed, af_verify_nsfail)?
2226 "Callback setup failed while verifying <%s>\n%s\n"
2227 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2228 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2229 "RFC requirements, and stops you from receiving standard bounce\n"
2230 "messages. This host does not accept mail from domains whose servers\n"
2233 "Verification failed for <%s>\n%s",
2234 sender_verified_failed->address,
2235 sender_verified_failed->user_message));
2237 rcpt_in_progress = save_rcpt_in_progress;
2240 /* Sort out text for logging */
2242 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2243 lognl = Ustrchr(log_msg, '\n');
2244 if (lognl != NULL) *lognl = 0;
2246 /* Send permanent failure response to the command, but the code used isn't
2247 always a 5xx one - see comments at the start of this function. If the original
2248 rc was FAIL_DROP we drop the connection and yield 2. */
2250 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2251 US"Administrative prohibition" : user_msg);
2253 /* Send temporary failure response to the command. Don't give any details,
2254 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2255 verb, and for a header verify when smtp_return_error_details is set.
2257 This conditional logic is all somewhat of a mess because of the odd
2258 interactions between temp_details and return_error_details. One day it should
2259 be re-implemented in a tidier fashion. */
2263 if (acl_temp_details && user_msg != NULL)
2265 if (smtp_return_error_details &&
2266 sender_verified_failed != NULL &&
2267 sender_verified_failed->message != NULL)
2269 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2271 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2274 smtp_respond(smtp_code, codelen, TRUE,
2275 US"Temporary local problem - please try later");
2278 /* Log the incident to the logs that are specified by log_reject_target
2279 (default main, reject). This can be empty to suppress logging of rejections. If
2280 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2281 is closing if required and return 2. */
2283 if (log_reject_target != 0)
2284 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2285 host_and_ident(TRUE),
2286 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2288 if (!drop) return 0;
2290 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2291 smtp_get_connection_info());
2293 /* Run the not-quit ACL, but without any custom messages. This should not be a
2294 problem, because we get here only if some other ACL has issued "drop", and
2295 in that case, *its* custom messages will have been used above. */
2297 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2304 /*************************************************
2305 * Handle SMTP exit when QUIT is not given *
2306 *************************************************/
2308 /* This function provides a logging/statistics hook for when an SMTP connection
2309 is dropped on the floor or the other end goes away. It's a global function
2310 because it's called from receive.c as well as this module. As well as running
2311 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2312 response, either with a custom message from the ACL, or using a default. There
2313 is one case, however, when no message is output - after "drop". In that case,
2314 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2315 passed to this function.
2317 In case things go wrong while processing this function, causing an error that
2318 may re-enter this funtion, there is a recursion check.
2321 reason What $smtp_notquit_reason will be set to in the ACL;
2322 if NULL, the ACL is not run
2323 code The error code to return as part of the response
2324 defaultrespond The default message if there's no user_msg
2330 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2333 uschar *user_msg = NULL;
2334 uschar *log_msg = NULL;
2336 /* Check for recursive acll */
2338 if (smtp_exit_function_called)
2340 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2344 smtp_exit_function_called = TRUE;
2346 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2348 if (acl_smtp_notquit != NULL && reason != NULL)
2350 smtp_notquit_reason = reason;
2351 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2354 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2358 /* Write an SMTP response if we are expected to give one. As the default
2359 responses are all internal, they should always fit in the buffer, but code a
2360 warning, just in case. Note that string_vformat() still leaves a complete
2361 string, even if it is incomplete. */
2363 if (code != NULL && defaultrespond != NULL)
2365 if (user_msg == NULL)
2369 va_start(ap, defaultrespond);
2370 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2371 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2372 smtp_printf("%s %s\r\n", code, buffer);
2376 smtp_respond(code, 3, TRUE, user_msg);
2384 /*************************************************
2385 * Verify HELO argument *
2386 *************************************************/
2388 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2389 matched. It is also called from ACL processing if verify = helo is used and
2390 verification was not previously tried (i.e. helo_try_verify_hosts was not
2391 matched). The result of its processing is to set helo_verified and
2392 helo_verify_failed. These variables should both be FALSE for this function to
2395 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2396 for IPv6 ::ffff: literals.
2399 Returns: TRUE if testing was completed;
2400 FALSE on a temporary failure
2404 smtp_verify_helo(void)
2408 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2411 if (sender_helo_name == NULL)
2413 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2416 /* Deal with the case of -bs without an IP address */
2418 else if (sender_host_address == NULL)
2420 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2421 helo_verified = TRUE;
2424 /* Deal with the more common case when there is a sending IP address */
2426 else if (sender_helo_name[0] == '[')
2428 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2429 Ustrlen(sender_host_address)) == 0;
2434 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2435 helo_verified = Ustrncmp(sender_helo_name + 1,
2436 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2441 { if (helo_verified) debug_printf("matched host address\n"); }
2444 /* Do a reverse lookup if one hasn't already given a positive or negative
2445 response. If that fails, or the name doesn't match, try checking with a forward
2450 if (sender_host_name == NULL && !host_lookup_failed)
2451 yield = host_name_lookup() != DEFER;
2453 /* If a host name is known, check it and all its aliases. */
2455 if (sender_host_name != NULL)
2457 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2461 HDEBUG(D_receive) debug_printf("matched host name\n");
2465 uschar **aliases = sender_host_aliases;
2466 while (*aliases != NULL)
2468 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2469 if (helo_verified) break;
2474 debug_printf("matched alias %s\n", *(--aliases));
2479 /* Final attempt: try a forward lookup of the helo name */
2485 h.name = sender_helo_name;
2489 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2491 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2492 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2497 if (Ustrcmp(hh->address, sender_host_address) == 0)
2499 helo_verified = TRUE;
2501 debug_printf("IP address for %s matches calling address\n",
2511 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2518 /*************************************************
2519 * Send user response message *
2520 *************************************************/
2522 /* This function is passed a default response code and a user message. It calls
2523 smtp_message_code() to check and possibly modify the response code, and then
2524 calls smtp_respond() to transmit the response. I put this into a function
2525 just to avoid a lot of repetition.
2528 code the response code
2529 user_msg the user message
2535 smtp_user_msg(uschar *code, uschar *user_msg)
2538 smtp_message_code(&code, &len, &user_msg, NULL);
2539 smtp_respond(code, len, TRUE, user_msg);
2545 /*************************************************
2546 * Initialize for SMTP incoming message *
2547 *************************************************/
2549 /* This function conducts the initial dialogue at the start of an incoming SMTP
2550 message, and builds a list of recipients. However, if the incoming message
2551 is part of a batch (-bS option) a separate function is called since it would
2552 be messy having tests splattered about all over this function. This function
2553 therefore handles the case where interaction is occurring. The input and output
2554 files are set up in smtp_in and smtp_out.
2556 The global recipients_list is set to point to a vector of recipient_item
2557 blocks, whose number is given by recipients_count. This is extended by the
2558 receive_add_recipient() function. The global variable sender_address is set to
2559 the sender's address. The yield is +1 if a message has been successfully
2560 started, 0 if a QUIT command was encountered or the connection was refused from
2561 the particular host, or -1 if the connection was lost.
2565 Returns: > 0 message successfully started (reached DATA)
2566 = 0 QUIT read or end of file reached or call refused
2571 smtp_setup_msg(void)
2574 BOOL toomany = FALSE;
2575 BOOL discarded = FALSE;
2576 BOOL last_was_rej_mail = FALSE;
2577 BOOL last_was_rcpt = FALSE;
2578 void *reset_point = store_get(0);
2580 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2582 /* Reset for start of new message. We allow one RSET not to be counted as a
2583 nonmail command, for those MTAs that insist on sending it between every
2584 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2585 TLS between messages (an Exim client may do this if it has messages queued up
2586 for the host). Note: we do NOT reset AUTH at this point. */
2588 smtp_reset(reset_point);
2589 message_ended = END_NOTSTARTED;
2591 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2592 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2593 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2595 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2598 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2600 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2602 /* Batched SMTP is handled in a different function. */
2604 if (smtp_batched_input) return smtp_setup_batch_msg();
2606 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2607 value. The values are 2 larger than the required yield of the function. */
2612 uschar *etrn_command;
2613 uschar *etrn_serialize_key;
2615 uschar *log_msg, *smtp_code;
2616 uschar *user_msg = NULL;
2617 uschar *recipient = NULL;
2618 uschar *hello = NULL;
2619 uschar *set_id = NULL;
2621 BOOL was_rej_mail = FALSE;
2622 BOOL was_rcpt = FALSE;
2623 void (*oldsignal)(int);
2625 int start, end, sender_domain, recipient_domain;
2630 switch(smtp_read_command(TRUE))
2632 /* The AUTH command is not permitted to occur inside a transaction, and may
2633 occur successfully only once per connection. Actually, that isn't quite
2634 true. When TLS is started, all previous information about a connection must
2635 be discarded, so a new AUTH is permitted at that time.
2637 AUTH may only be used when it has been advertised. However, it seems that
2638 there are clients that send AUTH when it hasn't been advertised, some of
2639 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2640 So there's a get-out that allows this to happen.
2642 AUTH is initially labelled as a "nonmail command" so that one occurrence
2643 doesn't get counted. We change the label here so that multiple failing
2644 AUTHS will eventually hit the nonmail threshold. */
2648 authentication_failed = TRUE;
2649 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2651 if (!auth_advertised && !allow_auth_unadvertised)
2653 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2654 US"AUTH command used when not advertised");
2657 if (sender_host_authenticated != NULL)
2659 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2660 US"already authenticated");
2663 if (sender_address != NULL)
2665 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2666 US"not permitted in mail transaction");
2672 if (acl_smtp_auth != NULL)
2674 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2677 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2682 /* Find the name of the requested authentication mechanism. */
2685 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
2687 if (!isalnum(c) && c != '-' && c != '_')
2689 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2690 US"invalid character in authentication mechanism name");
2696 /* If not at the end of the line, we must be at white space. Terminate the
2697 name and move the pointer on to any data that may be present. */
2699 if (*smtp_cmd_data != 0)
2701 *smtp_cmd_data++ = 0;
2702 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
2705 /* Search for an authentication mechanism which is configured for use
2706 as a server and which has been advertised (unless, sigh, allow_auth_
2707 unadvertised is set). */
2709 for (au = auths; au != NULL; au = au->next)
2711 if (strcmpic(s, au->public_name) == 0 && au->server &&
2712 (au->advertised || allow_auth_unadvertised)) break;
2717 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2718 string_sprintf("%s authentication mechanism not supported", s));
2722 /* Run the checking code, passing the remainder of the command line as
2723 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2724 it as the only set numerical variable. The authenticator may set $auth<n>
2725 and also set other numeric variables. The $auth<n> variables are preferred
2726 nowadays; the numerical variables remain for backwards compatibility.
2728 Afterwards, have a go at expanding the set_id string, even if
2729 authentication failed - for bad passwords it can be useful to log the
2730 userid. On success, require set_id to expand and exist, and put it in
2731 authenticated_id. Save this in permanent store, as the working store gets
2732 reset at HELO, RSET, etc. */
2734 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2736 expand_nlength[0] = 0; /* $0 contains nothing */
2738 c = (au->info->servercode)(au, smtp_cmd_data);
2739 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2740 expand_nmax = -1; /* Reset numeric variables */
2741 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2743 /* The value of authenticated_id is stored in the spool file and printed in
2744 log lines. It must not contain binary zeros or newline characters. In
2745 normal use, it never will, but when playing around or testing, this error
2746 can (did) happen. To guard against this, ensure that the id contains only
2747 printing characters. */
2749 if (set_id != NULL) set_id = string_printing(set_id);
2751 /* For the non-OK cases, set up additional logging data if set_id
2756 if (set_id != NULL && *set_id != 0)
2757 set_id = string_sprintf(" (set_id=%s)", set_id);
2761 /* Switch on the result */
2766 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2768 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2769 sender_host_authenticated = au->name;
2770 authentication_failed = FALSE;
2772 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2773 ((sender_host_address != NULL)? pnlocal : 0);
2774 s = ss = US"235 Authentication succeeded";
2775 authenticated_by = au;
2779 /* Authentication succeeded, but we failed to expand the set_id string.
2780 Treat this as a temporary error. */
2782 auth_defer_msg = expand_string_message;
2786 s = string_sprintf("435 Unable to authenticate at present%s",
2787 auth_defer_user_msg);
2788 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2789 set_id, auth_defer_msg);
2793 s = ss = US"501 Invalid base64 data";
2797 s = ss = US"501 Authentication cancelled";
2801 s = ss = US"553 Initial data not expected";
2805 s = US"535 Incorrect authentication data";
2806 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2810 s = US"435 Internal error";
2811 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2812 "check", set_id, c);
2816 smtp_printf("%s\r\n", s);
2818 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2819 au->name, host_and_ident(FALSE), ss);
2821 break; /* AUTH_CMD */
2823 /* The HELO/EHLO commands are permitted to appear in the middle of a
2824 session as well as at the beginning. They have the effect of a reset in
2825 addition to their other functions. Their absence at the start cannot be
2826 taken to be an error.
2830 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2831 or 502 failure replies MUST be returned as appropriate. The SMTP
2832 server MUST stay in the same state after transmitting these replies
2833 that it was in before the EHLO was received.
2835 Therefore, we do not do the reset until after checking the command for
2836 acceptability. This change was made for Exim release 4.11. Previously
2837 it did the reset first. */
2850 HELO_EHLO: /* Common code for HELO and EHLO */
2851 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2852 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2854 /* Reject the HELO if its argument was invalid or non-existent. A
2855 successful check causes the argument to be saved in malloc store. */
2857 if (!check_helo(smtp_cmd_data))
2859 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2861 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2862 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2863 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2864 string_printing(smtp_cmd_argument));
2866 if (++synprot_error_count > smtp_max_synprot_errors)
2868 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2869 "syntax or protocol errors (last command was \"%s\")",
2870 host_and_ident(FALSE), smtp_cmd_buffer);
2877 /* If sender_host_unknown is true, we have got here via the -bs interface,
2878 not called from inetd. Otherwise, we are running an IP connection and the
2879 host address will be set. If the helo name is the primary name of this
2880 host and we haven't done a reverse lookup, force one now. If helo_required
2881 is set, ensure that the HELO name matches the actual host. If helo_verify
2882 is set, do the same check, but softly. */
2884 if (!sender_host_unknown)
2886 BOOL old_helo_verified = helo_verified;
2887 uschar *p = smtp_cmd_data;
2889 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2892 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2893 because otherwise the log can be confusing. */
2895 if (sender_host_name == NULL &&
2896 (deliver_domain = sender_helo_name, /* set $domain */
2897 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2898 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2899 (void)host_name_lookup();
2901 /* Rebuild the fullhost info to include the HELO name (and the real name
2902 if it was looked up.) */
2904 host_build_sender_fullhost(); /* Rebuild */
2905 set_process_info("handling%s incoming connection from %s",
2906 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2908 /* Verify if configured. This doesn't give much security, but it does
2909 make some people happy to be able to do it. If helo_required is set,
2910 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2911 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2912 now obsolescent, since the verification can now be requested selectively
2915 helo_verified = helo_verify_failed = FALSE;
2916 if (helo_required || helo_verify)
2918 BOOL tempfail = !smtp_verify_helo();
2923 smtp_printf("%d %s argument does not match calling host\r\n",
2924 tempfail? 451 : 550, hello);
2925 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2926 tempfail? "temporarily " : "",
2927 hello, sender_helo_name, host_and_ident(FALSE));
2928 helo_verified = old_helo_verified;
2929 break; /* End of HELO/EHLO processing */
2931 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2932 "helo_try_verify_hosts\n", hello);
2937 #ifdef EXPERIMENTAL_SPF
2938 /* set up SPF context */
2939 spf_init(sender_helo_name, sender_host_address);
2942 /* Apply an ACL check if one is defined; afterwards, recheck
2943 synchronization in case the client started sending in a delay. */
2945 if (acl_smtp_helo != NULL)
2947 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2950 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2951 sender_helo_name = NULL;
2952 host_build_sender_fullhost(); /* Rebuild */
2955 else if (!check_sync()) goto SYNC_FAILURE;
2958 /* Generate an OK reply. The default string includes the ident if present,
2959 and also the IP address if present. Reflecting back the ident is intended
2960 as a deterrent to mail forgers. For maximum efficiency, and also because
2961 some broken systems expect each response to be in a single packet, arrange
2962 that the entire reply is sent in one write(). */
2964 auth_advertised = FALSE;
2965 pipelining_advertised = FALSE;
2967 tls_advertised = FALSE;
2970 smtp_code = US"250 "; /* Default response code plus space*/
2971 if (user_msg == NULL)
2973 s = string_sprintf("%.3s %s Hello %s%s%s",
2975 smtp_active_hostname,
2976 (sender_ident == NULL)? US"" : sender_ident,
2977 (sender_ident == NULL)? US"" : US" at ",
2978 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2983 if (sender_host_address != NULL)
2985 s = string_cat(s, &size, &ptr, US" [", 2);
2986 s = string_cat(s, &size, &ptr, sender_host_address,
2987 Ustrlen(sender_host_address));
2988 s = string_cat(s, &size, &ptr, US"]", 1);
2992 /* A user-supplied EHLO greeting may not contain more than one line. Note
2993 that the code returned by smtp_message_code() includes the terminating
2994 whitespace character. */
3000 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3001 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3002 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3004 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3005 "newlines: message truncated: %s", string_printing(s));
3012 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3014 /* If we received EHLO, we must create a multiline response which includes
3015 the functions supported. */
3021 /* I'm not entirely happy with this, as an MTA is supposed to check
3022 that it has enough room to accept a message of maximum size before
3023 it sends this. However, there seems little point in not sending it.
3024 The actual size check happens later at MAIL FROM time. By postponing it
3025 till then, VRFY and EXPN can be used after EHLO when space is short. */
3027 if (thismessage_size_limit > 0)
3029 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3030 thismessage_size_limit);
3031 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3035 s = string_cat(s, &size, &ptr, smtp_code, 3);
3036 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3039 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3040 clean; if it has an 8-bit character in its hand, it just sends it. It
3041 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3042 However, some users want this option simply in order to stop MUAs
3043 mangling messages that contain top-bit-set characters. It is therefore
3044 provided as an option. */
3046 if (accept_8bitmime)
3048 s = string_cat(s, &size, &ptr, smtp_code, 3);
3049 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3052 /* Advertise ETRN if there's an ACL checking whether a host is
3053 permitted to issue it; a check is made when any host actually tries. */
3055 if (acl_smtp_etrn != NULL)
3057 s = string_cat(s, &size, &ptr, smtp_code, 3);
3058 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3061 /* Advertise EXPN if there's an ACL checking whether a host is
3062 permitted to issue it; a check is made when any host actually tries. */
3064 if (acl_smtp_expn != NULL)
3066 s = string_cat(s, &size, &ptr, smtp_code, 3);
3067 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3070 /* Exim is quite happy with pipelining, so let the other end know that
3071 it is safe to use it, unless advertising is disabled. */
3073 if (pipelining_enable &&
3074 verify_check_host(&pipelining_advertise_hosts) == OK)
3076 s = string_cat(s, &size, &ptr, smtp_code, 3);
3077 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3078 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3079 pipelining_advertised = TRUE;
3082 /* If any server authentication mechanisms are configured, advertise
3083 them if the current host is in auth_advertise_hosts. The problem with
3084 advertising always is that some clients then require users to
3085 authenticate (and aren't configurable otherwise) even though it may not
3086 be necessary (e.g. if the host is in host_accept_relay).
3088 RFC 2222 states that SASL mechanism names contain only upper case
3089 letters, so output the names in upper case, though we actually recognize
3090 them in either case in the AUTH command. */
3094 if (verify_check_host(&auth_advertise_hosts) == OK)
3098 for (au = auths; au != NULL; au = au->next)
3100 if (au->server && (au->advertise_condition == NULL ||
3101 expand_check_condition(au->advertise_condition, au->name,
3102 US"authenticator")))
3107 s = string_cat(s, &size, &ptr, smtp_code, 3);
3108 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3110 auth_advertised = TRUE;
3113 s = string_cat(s, &size, &ptr, US" ", 1);
3114 s = string_cat(s, &size, &ptr, au->public_name,
3115 Ustrlen(au->public_name));
3116 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3117 au->advertised = TRUE;
3119 else au->advertised = FALSE;
3121 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3125 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3126 if it has been included in the binary, and the host matches
3127 tls_advertise_hosts. We must *not* advertise if we are already in a
3128 secure connection. */
3131 if (tls_active < 0 &&
3132 verify_check_host(&tls_advertise_hosts) != FAIL)
3134 s = string_cat(s, &size, &ptr, smtp_code, 3);
3135 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3136 tls_advertised = TRUE;
3140 /* Finish off the multiline reply with one that is always available. */
3142 s = string_cat(s, &size, &ptr, smtp_code, 3);
3143 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3146 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3152 if (tls_active >= 0) (void)tls_write(s, ptr); else
3155 (void)fwrite(s, 1, ptr, smtp_out);
3159 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3160 memmove(cr, cr + 1, (ptr--) - (cr - s));
3161 debug_printf("SMTP>> %s", s);
3165 /* Reset the protocol and the state, abandoning any previous message. */
3167 received_protocol = (esmtp?
3169 ((sender_host_authenticated != NULL)? pauthed : 0) +
3170 ((tls_active >= 0)? pcrpted : 0)]
3172 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
3174 ((sender_host_address != NULL)? pnlocal : 0);
3176 smtp_reset(reset_point);
3178 break; /* HELO/EHLO */
3181 /* The MAIL command requires an address as an operand. All we do
3182 here is to parse it for syntactic correctness. The form "<>" is
3183 a special case which converts into an empty string. The start/end
3184 pointers in the original are not used further for this address, as
3185 it is the canonical extracted address which is all that is kept. */
3189 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3190 was_rej_mail = TRUE; /* Reset if accepted */
3192 if (helo_required && !helo_seen)
3194 smtp_printf("503 HELO or EHLO required\r\n");
3195 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3196 "HELO/EHLO given", host_and_ident(FALSE));
3200 if (sender_address != NULL)
3202 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3203 US"sender already given");
3207 if (smtp_cmd_data[0] == 0)
3209 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3210 US"MAIL must have an address operand");
3214 /* Check to see if the limit for messages per connection would be
3215 exceeded by accepting further messages. */
3217 if (smtp_accept_max_per_connection > 0 &&
3218 smtp_mailcmd_count > smtp_accept_max_per_connection)
3220 smtp_printf("421 too many messages in this connection\r\n");
3221 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3222 "messages in one connection", host_and_ident(TRUE));
3226 /* Reset for start of message - even if this is going to fail, we
3227 obviously need to throw away any previous data. */
3229 smtp_reset(reset_point);
3231 sender_data = recipient_data = NULL;
3233 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3237 uschar *name, *value, *end;
3238 unsigned long int size;
3240 if (!extract_option(&name, &value)) break;
3242 /* Handle SIZE= by reading the value. We don't do the check till later,
3243 in order to be able to log the sender address on failure. */
3245 if (strcmpic(name, US"SIZE") == 0 &&
3246 ((size = Ustrtoul(value, &end, 10)), *end == 0))
3248 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3250 message_size = (int)size;
3253 /* If this session was initiated with EHLO and accept_8bitmime is set,
3254 Exim will have indicated that it supports the BODY=8BITMIME option. In
3255 fact, it does not support this according to the RFCs, in that it does not
3256 take any special action for forwarding messages containing 8-bit
3257 characters. That is why accept_8bitmime is not the default setting, but
3258 some sites want the action that is provided. We recognize both "8BITMIME"
3259 and "7BIT" as body types, but take no action. */
3261 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
3262 (strcmpic(value, US"8BITMIME") == 0 ||
3263 strcmpic(value, US"7BIT") == 0)) {}
3265 /* Handle the AUTH extension. If the value given is not "<>" and either
3266 the ACL says "yes" or there is no ACL but the sending host is
3267 authenticated, we set it up as the authenticated sender. However, if the
3268 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3269 the condition is met. The value of AUTH is an xtext, which means that +,
3270 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3273 else if (strcmpic(name, US"AUTH") == 0)
3275 if (Ustrcmp(value, "<>") != 0)
3280 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3282 /* Put back terminator overrides for error message */
3285 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3286 US"invalid data for AUTH");
3290 if (acl_smtp_mailauth == NULL)
3292 ignore_msg = US"client not authenticated";
3293 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3297 ignore_msg = US"rejected by ACL";
3298 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3299 &user_msg, &log_msg);
3305 if (authenticated_by == NULL ||
3306 authenticated_by->mail_auth_condition == NULL ||
3307 expand_check_condition(authenticated_by->mail_auth_condition,
3308 authenticated_by->name, US"authenticator"))
3309 break; /* Accept the AUTH */
3311 ignore_msg = US"server_mail_auth_condition failed";
3312 if (authenticated_id != NULL)
3313 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3314 ignore_msg, authenticated_id);
3319 authenticated_sender = NULL;
3320 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3321 value, host_and_ident(TRUE), ignore_msg);
3324 /* Should only get DEFER or ERROR here. Put back terminator
3325 overrides for error message */
3330 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3337 /* Unknown option. Stick back the terminator characters and break
3338 the loop. An error for a malformed address will occur. */
3348 /* If we have passed the threshold for rate limiting, apply the current
3349 delay, and update it for next time, provided this is a limited host. */
3351 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3352 verify_check_host(&smtp_ratelimit_hosts) == OK)
3354 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3355 smtp_delay_mail/1000.0);
3356 millisleep((int)smtp_delay_mail);
3357 smtp_delay_mail *= smtp_rlm_factor;
3358 if (smtp_delay_mail > (double)smtp_rlm_limit)
3359 smtp_delay_mail = (double)smtp_rlm_limit;
3362 /* Now extract the address, first applying any SMTP-time rewriting. The
3363 TRUE flag allows "<>" as a sender address. */
3365 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3366 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3367 global_rewrite_rules) : smtp_cmd_data;
3369 /* rfc821_domains = TRUE; << no longer needed */
3371 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3373 /* rfc821_domains = FALSE; << no longer needed */
3375 if (raw_sender == NULL)
3377 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3381 sender_address = raw_sender;
3383 /* If there is a configured size limit for mail, check that this message
3384 doesn't exceed it. The check is postponed to this point so that the sender
3387 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3389 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3390 log_write(L_size_reject,
3391 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3392 "message too big: size%s=%d max=%d",
3394 host_and_ident(TRUE),
3395 (message_size == INT_MAX)? ">" : "",
3397 thismessage_size_limit);
3398 sender_address = NULL;
3402 /* Check there is enough space on the disk unless configured not to.
3403 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3404 plus the current message - i.e. we accept the message only if it won't
3405 reduce the space below the threshold. Add 5000 to the size to allow for
3406 overheads such as the Received: line and storing of recipients, etc.
3407 By putting the check here, even when SIZE is not given, it allow VRFY
3408 and EXPN etc. to be used when space is short. */
3410 if (!receive_check_fs(
3411 (smtp_check_spool_space && message_size >= 0)?
3412 message_size + 5000 : 0))
3414 smtp_printf("452 Space shortage, please try later\r\n");
3415 sender_address = NULL;
3419 /* If sender_address is unqualified, reject it, unless this is a locally
3420 generated message, or the sending host or net is permitted to send
3421 unqualified addresses - typically local machines behaving as MUAs -
3422 in which case just qualify the address. The flag is set above at the start
3423 of the SMTP connection. */
3425 if (sender_domain == 0 && sender_address[0] != 0)
3427 if (allow_unqualified_sender)
3429 sender_domain = Ustrlen(sender_address) + 1;
3430 sender_address = rewrite_address_qualify(sender_address, FALSE);
3431 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3436 smtp_printf("501 %s: sender address must contain a domain\r\n",
3438 log_write(L_smtp_syntax_error,
3439 LOG_MAIN|LOG_REJECT,
3440 "unqualified sender rejected: <%s> %s%s",
3442 host_and_ident(TRUE),
3444 sender_address = NULL;
3449 /* Apply an ACL check if one is defined, before responding. Afterwards,
3450 when pipelining is not advertised, do another sync check in case the ACL
3451 delayed and the client started sending in the meantime. */
3453 if (acl_smtp_mail == NULL) rc = OK; else
3455 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3456 if (rc == OK && !pipelining_advertised && !check_sync())
3460 if (rc == OK || rc == DISCARD)
3462 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3463 else smtp_user_msg(US"250", user_msg);
3464 smtp_delay_rcpt = smtp_rlr_base;
3465 recipients_discarded = (rc == DISCARD);
3466 was_rej_mail = FALSE;
3470 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3471 sender_address = NULL;
3476 /* The RCPT command requires an address as an operand. There may be any
3477 number of RCPT commands, specifying multiple recipients. We build them all
3478 into a data structure. The start/end values given by parse_extract_address
3479 are not used, as we keep only the extracted address. */
3484 was_rcpt = rcpt_in_progress = TRUE;
3486 /* There must be a sender address; if the sender was rejected and
3487 pipelining was advertised, we assume the client was pipelining, and do not
3488 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3489 get the same treatment. */
3491 if (sender_address == NULL)
3493 if (pipelining_advertised && last_was_rej_mail)
3495 smtp_printf("503 sender not yet given\r\n");
3496 was_rej_mail = TRUE;
3500 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3501 US"sender not yet given");
3502 was_rcpt = FALSE; /* Not a valid RCPT */
3508 /* Check for an operand */
3510 if (smtp_cmd_data[0] == 0)
3512 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3513 US"RCPT must have an address operand");
3518 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3519 as a recipient address */
3521 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3522 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3523 global_rewrite_rules) : smtp_cmd_data;
3525 /* rfc821_domains = TRUE; << no longer needed */
3526 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3527 &recipient_domain, FALSE);
3528 /* rfc821_domains = FALSE; << no longer needed */
3530 if (recipient == NULL)
3532 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3537 /* If the recipient address is unqualified, reject it, unless this is a
3538 locally generated message. However, unqualified addresses are permitted
3539 from a configured list of hosts and nets - typically when behaving as
3540 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3541 really. The flag is set at the start of the SMTP connection.
3543 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3544 assumed this meant "reserved local part", but the revision of RFC 821 and
3545 friends now makes it absolutely clear that it means *mailbox*. Consequently
3546 we must always qualify this address, regardless. */
3548 if (recipient_domain == 0)
3550 if (allow_unqualified_recipient ||
3551 strcmpic(recipient, US"postmaster") == 0)
3553 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3555 recipient_domain = Ustrlen(recipient) + 1;
3556 recipient = rewrite_address_qualify(recipient, TRUE);
3561 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3563 log_write(L_smtp_syntax_error,
3564 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3565 "<%s> %s%s", recipient, host_and_ident(TRUE),
3571 /* Check maximum allowed */
3573 if (rcpt_count > recipients_max && recipients_max > 0)
3575 if (recipients_max_reject)
3578 smtp_printf("552 too many recipients\r\n");
3580 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3581 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3586 smtp_printf("452 too many recipients\r\n");
3588 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3589 "temporarily rejected: sender=<%s> %s", sender_address,
3590 host_and_ident(TRUE));
3597 /* If we have passed the threshold for rate limiting, apply the current
3598 delay, and update it for next time, provided this is a limited host. */
3600 if (rcpt_count > smtp_rlr_threshold &&
3601 verify_check_host(&smtp_ratelimit_hosts) == OK)
3603 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3604 smtp_delay_rcpt/1000.0);
3605 millisleep((int)smtp_delay_rcpt);
3606 smtp_delay_rcpt *= smtp_rlr_factor;
3607 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3608 smtp_delay_rcpt = (double)smtp_rlr_limit;
3611 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3612 for them. Otherwise, check the access control list for this recipient. As
3613 there may be a delay in this, re-check for a synchronization error
3614 afterwards, unless pipelining was advertised. */
3616 if (recipients_discarded) rc = DISCARD; else
3618 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
3620 if (rc == OK && !pipelining_advertised && !check_sync())
3624 /* The ACL was happy */
3628 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3629 else smtp_user_msg(US"250", user_msg);
3630 receive_add_recipient(recipient, -1);
3633 /* The recipient was discarded */
3635 else if (rc == DISCARD)
3637 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3638 else smtp_user_msg(US"250", user_msg);
3641 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3642 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3643 (sender_address_unrewritten != NULL)?
3644 sender_address_unrewritten : sender_address,
3645 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3646 (log_msg == NULL)? US"" : US": ",
3647 (log_msg == NULL)? US"" : log_msg);
3650 /* Either the ACL failed the address, or it was deferred. */
3654 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3655 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3660 /* The DATA command is legal only if it follows successful MAIL FROM
3661 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3662 not counted as a protocol error if it follows RCPT (which must have been
3663 rejected if there are no recipients.) This function is complete when a
3664 valid DATA command is encountered.
3666 Note concerning the code used: RFC 2821 says this:
3668 - If there was no MAIL, or no RCPT, command, or all such commands
3669 were rejected, the server MAY return a "command out of sequence"
3670 (503) or "no valid recipients" (554) reply in response to the
3673 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3674 because it is the same whether pipelining is in use or not.
3676 If all the RCPT commands that precede DATA provoked the same error message
3677 (often indicating some kind of system error), it is helpful to include it
3678 with the DATA rejection (an idea suggested by Tony Finch). */
3682 if (!discarded && recipients_count <= 0)
3684 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
3686 uschar *code = US"503";
3687 int len = Ustrlen(rcpt_smtp_response);
3688 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
3690 /* Responses from smtp_printf() will have \r\n on the end */
3691 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
3692 rcpt_smtp_response[len-2] = 0;
3693 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
3695 if (pipelining_advertised && last_was_rcpt)
3696 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
3698 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3699 US"valid RCPT command must precede DATA");
3703 if (toomany && recipients_max_reject)
3705 sender_address = NULL; /* This will allow a new MAIL without RSET */
3706 sender_address_unrewritten = NULL;
3707 smtp_printf("554 Too many recipients\r\n");
3711 /* If there is an ACL, re-check the synchronization afterwards, since the
3712 ACL may have delayed. */
3714 if (acl_smtp_predata == NULL) rc = OK; else
3716 enable_dollar_recipients = TRUE;
3717 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3719 enable_dollar_recipients = FALSE;
3720 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
3725 if (user_msg == NULL)
3726 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3727 else smtp_user_msg(US"354", user_msg);
3729 message_ended = END_NOTENDED; /* Indicate in middle of data */
3732 /* Either the ACL failed the address, or it was deferred. */
3735 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3741 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3743 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3749 /* rfc821_domains = TRUE; << no longer needed */
3750 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
3751 &recipient_domain, FALSE);
3752 /* rfc821_domains = FALSE; << no longer needed */
3754 if (address == NULL)
3755 s = string_sprintf("501 %s", errmess);
3758 address_item *addr = deliver_make_addr(address, FALSE);
3759 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3760 -1, -1, NULL, NULL, NULL))
3763 s = string_sprintf("250 <%s> is deliverable", address);
3767 s = (addr->user_message != NULL)?
3768 string_sprintf("451 <%s> %s", address, addr->user_message) :
3769 string_sprintf("451 Cannot resolve <%s> at this time", address);
3773 s = (addr->user_message != NULL)?
3774 string_sprintf("550 <%s> %s", address, addr->user_message) :
3775 string_sprintf("550 <%s> is not deliverable", address);
3776 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3777 smtp_cmd_argument, host_and_ident(TRUE));
3782 smtp_printf("%s\r\n", s);
3789 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3791 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3794 BOOL save_log_testing_mode = log_testing_mode;
3795 address_test_mode = log_testing_mode = TRUE;
3796 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
3797 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3799 address_test_mode = FALSE;
3800 log_testing_mode = save_log_testing_mode; /* true for -bh */
3809 if (!tls_advertised)
3811 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3812 US"STARTTLS command used when not advertised");
3816 /* Apply an ACL check if one is defined */
3818 if (acl_smtp_starttls != NULL)
3820 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3824 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3829 /* RFC 2487 is not clear on when this command may be sent, though it
3830 does state that all information previously obtained from the client
3831 must be discarded if a TLS session is started. It seems reasonble to
3832 do an implied RSET when STARTTLS is received. */
3834 incomplete_transaction_log(US"STARTTLS");
3835 smtp_reset(reset_point);
3837 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3839 /* Attempt to start up a TLS session, and if successful, discard all
3840 knowledge that was obtained previously. At least, that's what the RFC says,
3841 and that's what happens by default. However, in order to work round YAEB,
3842 there is an option to remember the esmtp state. Sigh.
3844 We must allow for an extra EHLO command and an extra AUTH command after
3845 STARTTLS that don't add to the nonmail command count. */
3847 if ((rc = tls_server_start(tls_require_ciphers, gnutls_require_mac,
3848 gnutls_require_kx, gnutls_require_proto)) == OK)
3850 if (!tls_remember_esmtp)
3851 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3852 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3853 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3854 if (sender_helo_name != NULL)
3856 store_free(sender_helo_name);
3857 sender_helo_name = NULL;
3858 host_build_sender_fullhost(); /* Rebuild */
3859 set_process_info("handling incoming TLS connection from %s",
3860 host_and_ident(FALSE));
3862 received_protocol = (esmtp?
3863 protocols[pextend + pcrpted +
3864 ((sender_host_authenticated != NULL)? pauthed : 0)]
3866 protocols[pnormal + pcrpted])
3868 ((sender_host_address != NULL)? pnlocal : 0);
3870 sender_host_authenticated = NULL;
3871 authenticated_id = NULL;
3872 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3873 DEBUG(D_tls) debug_printf("TLS active\n");
3874 break; /* Successful STARTTLS */
3877 /* Some local configuration problem was discovered before actually trying
3878 to do a TLS handshake; give a temporary error. */
3880 else if (rc == DEFER)
3882 smtp_printf("454 TLS currently unavailable\r\n");
3886 /* Hard failure. Reject everything except QUIT or closed connection. One
3887 cause for failure is a nested STARTTLS, in which case tls_active remains
3888 set, but we must still reject all incoming commands. */
3890 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3893 switch(smtp_read_command(FALSE))
3896 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3897 smtp_get_connection_info());
3898 smtp_notquit_exit(US"tls-failed", NULL, NULL);
3902 /* It is perhaps arguable as to which exit ACL should be called here,
3903 but as it is probably a situtation that almost never arises, it
3904 probably doesn't matter. We choose to call the real QUIT ACL, which in
3905 some sense is perhaps "right". */
3909 if (acl_smtp_quit != NULL)
3911 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
3914 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3917 if (user_msg == NULL)
3918 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3920 smtp_respond(US"221", 3, TRUE, user_msg);
3921 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3922 smtp_get_connection_info());
3927 smtp_printf("554 Security failure\r\n");
3936 /* The ACL for QUIT is provided for gathering statistical information or
3937 similar; it does not affect the response code, but it can supply a custom
3942 incomplete_transaction_log(US"QUIT");
3943 if (acl_smtp_quit != NULL)
3945 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
3947 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3950 if (user_msg == NULL)
3951 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3953 smtp_respond(US"221", 3, TRUE, user_msg);
3960 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3961 smtp_get_connection_info());
3967 incomplete_transaction_log(US"RSET");
3968 smtp_reset(reset_point);
3970 smtp_printf("250 Reset OK\r\n");
3971 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3977 smtp_printf("250 OK\r\n");
3981 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
3982 used, a check will be done for permitted hosts. Show STARTTLS only if not
3983 already in a TLS session and if it would be advertised in the EHLO
3988 smtp_printf("214-Commands supported:\r\n");
3992 Ustrcat(buffer, " AUTH");
3994 if (tls_active < 0 &&
3995 verify_check_host(&tls_advertise_hosts) != FAIL)
3996 Ustrcat(buffer, " STARTTLS");
3998 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3999 Ustrcat(buffer, " NOOP QUIT RSET HELP");
4000 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4001 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4002 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4003 smtp_printf("214%s\r\n", buffer);
4009 incomplete_transaction_log(US"connection lost");
4010 smtp_notquit_exit(US"connection-lost", US"421",
4011 US"%s lost input connection", smtp_active_hostname);
4013 /* Don't log by default unless in the middle of a message, as some mailers
4014 just drop the call rather than sending QUIT, and it clutters up the logs.
4017 if (sender_address != NULL || recipients_count > 0)
4018 log_write(L_lost_incoming_connection,
4020 "unexpected %s while reading SMTP command from %s%s",
4021 sender_host_unknown? "EOF" : "disconnection",
4022 host_and_ident(FALSE), smtp_read_error);
4024 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4025 smtp_get_connection_info(), smtp_read_error);
4033 if (sender_address != NULL)
4035 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4036 US"ETRN is not permitted inside a transaction");
4040 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4041 host_and_ident(FALSE));
4043 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4046 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4050 /* Compute the serialization key for this command. */
4052 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4054 /* If a command has been specified for running as a result of ETRN, we
4055 permit any argument to ETRN. If not, only the # standard form is permitted,
4056 since that is strictly the only kind of ETRN that can be implemented
4057 according to the RFC. */
4059 if (smtp_etrn_command != NULL)
4063 etrn_command = smtp_etrn_command;
4064 deliver_domain = smtp_cmd_data;
4065 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4066 US"ETRN processing", &error);
4067 deliver_domain = NULL;
4070 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4072 smtp_printf("458 Internal failure\r\n");
4077 /* Else set up to call Exim with the -R option. */
4081 if (*smtp_cmd_data++ != '#')
4083 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4084 US"argument must begin with #");
4087 etrn_command = US"exim -R";
4088 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4092 /* If we are host-testing, don't actually do anything. */
4098 debug_printf("ETRN command is: %s\n", etrn_command);
4099 debug_printf("ETRN command execution skipped\n");
4101 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4102 else smtp_user_msg(US"250", user_msg);
4107 /* If ETRN queue runs are to be serialized, check the database to
4108 ensure one isn't already running. */
4110 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4112 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4116 /* Fork a child process and run the command. We don't want to have to
4117 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4118 forking. It should be set that way anyway for external incoming SMTP,
4119 but we save and restore to be tidy. If serialization is required, we
4120 actually run the command in yet another process, so we can wait for it
4121 to complete and then remove the serialization lock. */
4123 oldsignal = signal(SIGCHLD, SIG_IGN);
4125 if ((pid = fork()) == 0)
4127 smtp_input = FALSE; /* This process is not associated with the */
4128 (void)fclose(smtp_in); /* SMTP call any more. */
4129 (void)fclose(smtp_out);
4131 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
4133 /* If not serializing, do the exec right away. Otherwise, fork down
4134 into another process. */
4136 if (!smtp_etrn_serialize || (pid = fork()) == 0)
4138 DEBUG(D_exec) debug_print_argv(argv);
4139 exim_nullstd(); /* Ensure std{in,out,err} exist */
4140 execv(CS argv[0], (char *const *)argv);
4141 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
4142 etrn_command, strerror(errno));
4143 _exit(EXIT_FAILURE); /* paranoia */
4146 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4147 is, we are in the first subprocess, after forking again. All we can do
4148 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4149 complete, before removing the serialization. */
4152 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4153 "failed: %s", strerror(errno));
4157 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4159 (void)wait(&status);
4160 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4164 enq_end(etrn_serialize_key);
4165 _exit(EXIT_SUCCESS);
4168 /* Back in the top level SMTP process. Check that we started a subprocess
4169 and restore the signal state. */
4173 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4175 smtp_printf("458 Unable to fork process\r\n");
4176 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4180 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4181 else smtp_user_msg(US"250", user_msg);
4184 signal(SIGCHLD, oldsignal);
4189 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4190 US"unexpected argument data");
4194 /* This currently happens only for NULLs, but could be extended. */
4197 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
4198 US"NULL character(s) present (shown as '?')");
4199 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
4205 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
4206 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
4207 c = smtp_inend - smtp_inptr;
4208 if (c > 150) c = 150;
4210 incomplete_transaction_log(US"sync failure");
4211 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
4212 "(next input sent too soon: pipelining was%s advertised): "
4213 "rejected \"%s\" %s next input=\"%s\"",
4214 pipelining_advertised? "" : " not",
4215 smtp_cmd_buffer, host_and_ident(TRUE),
4216 string_printing(smtp_inptr));
4217 smtp_notquit_exit(US"synchronization-error", US"554",
4218 US"SMTP synchronization error");
4219 done = 1; /* Pretend eof - drops connection */
4223 case TOO_MANY_NONMAIL_CMD:
4224 s = smtp_cmd_buffer;
4225 while (*s != 0 && !isspace(*s)) s++;
4226 incomplete_transaction_log(US"too many non-mail commands");
4227 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4228 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
4229 s - smtp_cmd_buffer, smtp_cmd_buffer);
4230 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
4231 done = 1; /* Pretend eof - drops connection */
4236 if (unknown_command_count++ >= smtp_max_unknown_commands)
4238 log_write(L_smtp_syntax_error, LOG_MAIN,
4239 "SMTP syntax error in \"%s\" %s %s",
4240 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
4241 US"unrecognized command");
4242 incomplete_transaction_log(US"unrecognized command");
4243 smtp_notquit_exit(US"bad-commands", US"500",
4244 US"Too many unrecognized commands");
4246 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4247 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
4251 done = synprot_error(L_smtp_syntax_error, 500, NULL,
4252 US"unrecognized command");
4256 /* This label is used by goto's inside loops that want to break out to
4257 the end of the command-processing loop. */
4260 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
4261 last_was_rcpt = was_rcpt; /* protocol error handling */
4265 return done - 2; /* Convert yield values */
4268 /* End of smtp_in.c */
git://git.exim.org / users / jgh / exim.git / blob