1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.56 2007/03/21 15:10:39 ph10 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 int synprot_error_count;
127 static int unknown_command_count;
128 static int sync_cmd_limit;
129 static int smtp_write_error = 0;
131 static uschar *rcpt_smtp_response;
132 static uschar *smtp_data_buffer;
133 static uschar *smtp_cmd_data;
135 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
136 final fields of all except AUTH are forced TRUE at the start of a new message
137 setup, to allow one of each between messages that is not counted as a nonmail
138 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
139 allow a new EHLO after starting up TLS.
141 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
142 counted. However, the flag is changed when AUTH is received, so that multiple
143 failing AUTHs will eventually hit the limit. After a successful AUTH, another
144 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
145 forced TRUE, to allow for the re-authentication that can happen at that point.
147 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
148 count of non-mail commands and possibly provoke an error. */
150 static smtp_cmd_list cmd_list[] = {
151 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
152 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
153 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
154 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
156 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
159 /* If you change anything above here, also fix the definitions below. */
161 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
162 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
163 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
164 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
165 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
166 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
167 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
168 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
169 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
172 static smtp_cmd_list *cmd_list_end =
173 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
175 #define CMD_LIST_RSET 0
176 #define CMD_LIST_HELO 1
177 #define CMD_LIST_EHLO 2
178 #define CMD_LIST_AUTH 3
179 #define CMD_LIST_STARTTLS 4
181 /* This list of names is used for performing the smtp_no_mail logging action.
182 It must be kept in step with the SCH_xxx enumerations. */
184 static uschar *smtp_names[] =
186 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
187 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
190 static uschar *protocols[] = {
191 US"local-smtp", /* HELO */
192 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
193 US"local-esmtp", /* EHLO */
194 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
195 US"local-esmtpa", /* EHLO->AUTH */
196 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
201 #define pcrpted 1 /* added to pextend or pnormal */
202 #define pauthed 2 /* added to pextend */
203 #define pnlocal 6 /* offset to remove "local" */
205 /* When reading SMTP from a remote host, we have to use our own versions of the
206 C input-reading functions, in order to be able to flush the SMTP output only
207 when about to read more data from the socket. This is the only way to get
208 optimal performance when the client is using pipelining. Flushing for every
209 command causes a separate packet and reply packet each time; saving all the
210 responses up (when pipelining) combines them into one packet and one response.
212 For simplicity, these functions are used for *all* SMTP input, not only when
213 receiving over a socket. However, after setting up a secure socket (SSL), input
214 is read via the OpenSSL library, and another set of functions is used instead
217 These functions are set in the receive_getc etc. variables and called with the
218 same interface as the C functions. However, since there can only ever be
219 one incoming SMTP call, we just use a single buffer and flags. There is no need
220 to implement a complicated private FILE-like structure.*/
222 static uschar *smtp_inbuffer;
223 static uschar *smtp_inptr;
224 static uschar *smtp_inend;
225 static int smtp_had_eof;
226 static int smtp_had_error;
229 /*************************************************
230 * SMTP version of getc() *
231 *************************************************/
233 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
234 it flushes the output, and refills the buffer, with a timeout. The signal
235 handler is set appropriately by the calling function. This function is not used
236 after a connection has negotated itself into an TLS/SSL state.
239 Returns: the next character or EOF
245 if (smtp_inptr >= smtp_inend)
249 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
250 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
255 /* Must put the error text in fixed store, because this might be during
256 header reading, where it releases unused store above the header. */
259 smtp_had_error = save_errno;
260 smtp_read_error = string_copy_malloc(
261 string_sprintf(" (error: %s)", strerror(save_errno)));
263 else smtp_had_eof = 1;
266 smtp_inend = smtp_inbuffer + rc;
267 smtp_inptr = smtp_inbuffer;
269 return *smtp_inptr++;
274 /*************************************************
275 * SMTP version of ungetc() *
276 *************************************************/
278 /* Puts a character back in the input buffer. Only ever
284 Returns: the character
290 *(--smtp_inptr) = ch;
297 /*************************************************
298 * SMTP version of feof() *
299 *************************************************/
301 /* Tests for a previous EOF
304 Returns: non-zero if the eof flag is set
316 /*************************************************
317 * SMTP version of ferror() *
318 *************************************************/
320 /* Tests for a previous read error, and returns with errno
321 restored to what it was when the error was detected.
324 Returns: non-zero if the error flag is set
330 errno = smtp_had_error;
331 return smtp_had_error;
337 /*************************************************
338 * Write formatted string to SMTP channel *
339 *************************************************/
341 /* This is a separate function so that we don't have to repeat everything for
342 TLS support or debugging. It is global so that the daemon and the
343 authentication functions can use it. It does not return any error indication,
344 because major problems such as dropped connections won't show up till an output
345 flush for non-TLS connections. The smtp_fflush() function is available for
346 checking that: for convenience, TLS output errors are remembered here so that
347 they are also picked up later by smtp_fflush().
351 ... optional arguments
357 smtp_printf(char *format, ...)
364 va_start(ap, format);
365 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
367 end = big_buffer + Ustrlen(big_buffer);
368 while ((cr = Ustrchr(big_buffer, '\r')) != NULL) /* lose CRs */
369 memmove(cr, cr + 1, (end--) - cr);
370 debug_printf("SMTP>> %s", big_buffer);
373 va_start(ap, format);
374 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
376 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
377 smtp_closedown(US"Unexpected error");
378 exim_exit(EXIT_FAILURE);
382 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
383 have had the same. Note: this code is also present in smtp_respond(). It would
384 be tidier to have it only in one place, but when it was added, it was easier to
385 do it that way, so as not to have to mess with the code for the RCPT command,
386 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
388 if (rcpt_in_progress)
390 if (rcpt_smtp_response == NULL)
391 rcpt_smtp_response = string_copy(big_buffer);
392 else if (rcpt_smtp_response_same &&
393 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
394 rcpt_smtp_response_same = FALSE;
395 rcpt_in_progress = FALSE;
398 /* Now write the string */
403 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
408 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
413 /*************************************************
414 * Flush SMTP out and check for error *
415 *************************************************/
417 /* This function isn't currently used within Exim (it detects errors when it
418 tries to read the next SMTP input), but is available for use in local_scan().
419 For non-TLS connections, it flushes the output and checks for errors. For
420 TLS-connections, it checks for a previously-detected TLS write error.
423 Returns: 0 for no error; -1 after an error
429 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
430 return smtp_write_error;
435 /*************************************************
436 * SMTP command read timeout *
437 *************************************************/
439 /* Signal handler for timing out incoming SMTP commands. This attempts to
442 Argument: signal number (SIGALRM)
447 command_timeout_handler(int sig)
449 sig = sig; /* Keep picky compilers happy */
450 log_write(L_lost_incoming_connection,
451 LOG_MAIN, "SMTP command timeout on%s connection from %s",
452 (tls_active >= 0)? " TLS" : "",
453 host_and_ident(FALSE));
454 if (smtp_batched_input)
455 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
456 smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
457 smtp_active_hostname);
459 exim_exit(EXIT_FAILURE);
464 /*************************************************
466 *************************************************/
468 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
470 Argument: signal number (SIGTERM)
475 command_sigterm_handler(int sig)
477 sig = sig; /* Keep picky compilers happy */
478 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
479 if (smtp_batched_input)
480 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
481 smtp_printf("421 %s: Service not available - closing connection\r\n",
482 smtp_active_hostname);
483 exim_exit(EXIT_FAILURE);
489 /*************************************************
490 * Read one command line *
491 *************************************************/
493 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
494 There are sites that don't do this, and in any case internal SMTP probably
495 should check only for LF. Consequently, we check here for LF only. The line
496 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
497 an unknown command. The command is read into the global smtp_cmd_buffer so that
498 it is available via $smtp_command.
500 The character reading routine sets up a timeout for each block actually read
501 from the input (which may contain more than one command). We set up a special
502 signal handler that closes down the session on a timeout. Control does not
506 check_sync if TRUE, check synchronization rules if global option is TRUE
508 Returns: a code identifying the command (enumerated above)
512 smtp_read_command(BOOL check_sync)
517 BOOL hadnull = FALSE;
519 os_non_restarting_signal(SIGALRM, command_timeout_handler);
521 while ((c = (receive_getc)()) != '\n' && c != EOF)
523 if (ptr >= smtp_cmd_buffer_size)
525 os_non_restarting_signal(SIGALRM, sigalrm_handler);
533 smtp_cmd_buffer[ptr++] = c;
536 receive_linecount++; /* For BSMTP errors */
537 os_non_restarting_signal(SIGALRM, sigalrm_handler);
539 /* If hit end of file, return pseudo EOF command. Whether we have a
540 part-line already read doesn't matter, since this is an error state. */
542 if (c == EOF) return EOF_CMD;
544 /* Remove any CR and white space at the end of the line, and terminate the
547 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
548 smtp_cmd_buffer[ptr] = 0;
550 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
552 /* NULLs are not allowed in SMTP commands */
554 if (hadnull) return BADCHAR_CMD;
556 /* Scan command list and return identity, having set the data pointer
557 to the start of the actual data characters. Check for SMTP synchronization
560 for (p = cmd_list; p < cmd_list_end; p++)
562 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
563 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
564 smtp_cmd_buffer[p->len] == 0 ||
565 smtp_cmd_buffer[p->len] == ' '))
567 if (smtp_inptr < smtp_inend && /* Outstanding input */
568 p->cmd < sync_cmd_limit && /* Command should sync */
569 check_sync && /* Local flag set */
570 smtp_enforce_sync && /* Global flag set */
571 sender_host_address != NULL && /* Not local input */
572 !sender_host_notsocket) /* Really is a socket */
575 /* The variables $smtp_command and $smtp_command_argument point into the
576 unmodified input buffer. A copy of the latter is taken for actual
577 processing, so that it can be chopped up into separate parts if necessary,
578 for example, when processing a MAIL command options such as SIZE that can
579 follow the sender address. */
581 smtp_cmd_argument = smtp_cmd_buffer + p->len;
582 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
583 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
584 smtp_cmd_data = smtp_data_buffer;
586 /* Count non-mail commands from those hosts that are controlled in this
587 way. The default is all hosts. We don't waste effort checking the list
588 until we get a non-mail command, but then cache the result to save checking
589 again. If there's a DEFER while checking the host, assume it's in the list.
591 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
592 start of each incoming message by fiddling with the value in the table. */
596 if (count_nonmail == TRUE_UNSET) count_nonmail =
597 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
598 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
599 return TOO_MANY_NONMAIL_CMD;
602 /* If there is data for a command that does not expect it, generate the
605 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
609 /* Enforce synchronization for unknown commands */
611 if (smtp_inptr < smtp_inend && /* Outstanding input */
612 check_sync && /* Local flag set */
613 smtp_enforce_sync && /* Global flag set */
614 sender_host_address != NULL && /* Not local input */
615 !sender_host_notsocket) /* Really is a socket */
623 /*************************************************
624 * Recheck synchronization *
625 *************************************************/
627 /* Synchronization checks can never be perfect because a packet may be on its
628 way but not arrived when the check is done. Such checks can in any case only be
629 done when TLS is not in use. Normally, the checks happen when commands are
630 read: Exim ensures that there is no more input in the input buffer. In normal
631 cases, the response to the command will be fast, and there is no further check.
633 However, for some commands an ACL is run, and that can include delays. In those
634 cases, it is useful to do another check on the input just before sending the
635 response. This also applies at the start of a connection. This function does
636 that check by means of the select() function, as long as the facility is not
637 disabled or inappropriate. A failure of select() is ignored.
639 When there is unwanted input, we read it so that it appears in the log of the
643 Returns: TRUE if all is well; FALSE if there is input pending
651 struct timeval tzero;
653 if (!smtp_enforce_sync || sender_host_address == NULL ||
654 sender_host_notsocket || tls_active >= 0)
657 fd = fileno(smtp_in);
662 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
664 if (rc <= 0) return TRUE; /* Not ready to read */
666 if (rc < 0) return TRUE; /* End of file or error */
669 rc = smtp_inend - smtp_inptr;
670 if (rc > 150) rc = 150;
677 /*************************************************
678 * Forced closedown of call *
679 *************************************************/
681 /* This function is called from log.c when Exim is dying because of a serious
682 disaster, and also from some other places. If an incoming non-batched SMTP
683 channel is open, it swallows the rest of the incoming message if in the DATA
684 phase, sends the reply string, and gives an error to all subsequent commands
685 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
688 Argument: SMTP reply string to send, excluding the code
693 smtp_closedown(uschar *message)
695 if (smtp_in == NULL || smtp_batched_input) return;
696 receive_swallow_smtp();
697 smtp_printf("421 %s\r\n", message);
701 switch(smtp_read_command(FALSE))
707 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
712 smtp_printf("250 Reset OK\r\n");
716 smtp_printf("421 %s\r\n", message);
725 /*************************************************
726 * Set up connection info for logging *
727 *************************************************/
729 /* This function is called when logging information about an SMTP connection.
730 It sets up appropriate source information, depending on the type of connection.
731 If sender_fullhost is NULL, we are at a very early stage of the connection;
732 just use the IP address.
735 Returns: a string describing the connection
739 smtp_get_connection_info(void)
741 uschar *hostname = (sender_fullhost == NULL)?
742 sender_host_address : sender_fullhost;
745 return string_sprintf("SMTP connection from %s", hostname);
747 if (sender_host_unknown || sender_host_notsocket)
748 return string_sprintf("SMTP connection from %s", sender_ident);
751 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
753 if ((log_extra_selector & LX_incoming_interface) != 0 &&
754 interface_address != NULL)
755 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
756 interface_address, interface_port);
758 return string_sprintf("SMTP connection from %s", hostname);
763 /*************************************************
764 * Log lack of MAIL if so configured *
765 *************************************************/
767 /* This function is called when an SMTP session ends. If the log selector
768 smtp_no_mail is set, write a log line giving some details of what has happened
776 smtp_log_no_mail(void)
781 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
787 if (sender_host_authenticated != NULL)
789 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
790 if (authenticated_id != NULL)
791 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
795 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_cipher != NULL)
796 s = string_append(s, &size, &ptr, 2, US" X=", tls_cipher);
797 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
799 s = string_append(s, &size, &ptr, 2, US" CV=",
800 tls_certificate_verified? "yes":"no");
801 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_peerdn != NULL)
802 s = string_append(s, &size, &ptr, 3, US" DN=\"", tls_peerdn, US"\"");
805 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
806 US" C=..." : US" C=";
807 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
809 if (smtp_connection_had[i] != SCH_NONE)
811 s = string_append(s, &size, &ptr, 2, sep,
812 smtp_names[smtp_connection_had[i]]);
817 for (i = 0; i < smtp_ch_index; i++)
819 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
823 if (s != NULL) s[ptr] = 0; else s = US"";
824 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
825 host_and_ident(FALSE),
826 readconf_printtime(time(NULL) - smtp_connection_start), s);
831 /*************************************************
832 * Check HELO line and set sender_helo_name *
833 *************************************************/
835 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
836 the domain name of the sending host, or an ip literal in square brackets. The
837 arrgument is placed in sender_helo_name, which is in malloc store, because it
838 must persist over multiple incoming messages. If helo_accept_junk is set, this
839 host is permitted to send any old junk (needed for some broken hosts).
840 Otherwise, helo_allow_chars can be used for rogue characters in general
841 (typically people want to let in underscores).
844 s the data portion of the line (already past any white space)
846 Returns: TRUE or FALSE
850 check_helo(uschar *s)
853 uschar *end = s + Ustrlen(s);
854 BOOL yield = helo_accept_junk;
856 /* Discard any previous helo name */
858 if (sender_helo_name != NULL)
860 store_free(sender_helo_name);
861 sender_helo_name = NULL;
864 /* Skip tests if junk is permitted. */
868 /* Allow the new standard form for IPv6 address literals, namely,
869 [IPv6:....], and because someone is bound to use it, allow an equivalent
870 IPv4 form. Allow plain addresses as well. */
877 if (strncmpic(s, US"[IPv6:", 6) == 0)
878 yield = (string_is_ip_address(s+6, NULL) == 6);
879 else if (strncmpic(s, US"[IPv4:", 6) == 0)
880 yield = (string_is_ip_address(s+6, NULL) == 4);
882 yield = (string_is_ip_address(s+1, NULL) != 0);
887 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
888 that have been configured (usually underscore - sigh). */
895 if (!isalnum(*s) && *s != '.' && *s != '-' &&
896 Ustrchr(helo_allow_chars, *s) == NULL)
906 /* Save argument if OK */
908 if (yield) sender_helo_name = string_copy_malloc(start);
916 /*************************************************
917 * Extract SMTP command option *
918 *************************************************/
920 /* This function picks the next option setting off the end of smtp_cmd_data. It
921 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
922 things that can appear there.
925 name point this at the name
926 value point this at the data string
928 Returns: TRUE if found an option
932 extract_option(uschar **name, uschar **value)
935 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
936 while (isspace(*v)) v--;
939 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
940 if (*v != '=') return FALSE;
943 while(isalpha(n[-1])) n--;
945 if (n[-1] != ' ') return FALSE;
958 /*************************************************
959 * Reset for new message *
960 *************************************************/
962 /* This function is called whenever the SMTP session is reset from
963 within either of the setup functions.
965 Argument: the stacking pool storage reset point
970 smtp_reset(void *reset_point)
972 store_reset(reset_point);
973 recipients_list = NULL;
974 rcpt_count = rcpt_defer_count = rcpt_fail_count =
975 raw_recipients_count = recipients_count = recipients_list_max = 0;
976 message_linecount = 0;
978 acl_added_headers = NULL;
979 queue_only_policy = FALSE;
980 rcpt_smtp_response = NULL;
981 rcpt_smtp_response_same = TRUE;
982 rcpt_in_progress = FALSE;
983 deliver_freeze = FALSE; /* Can be set by ACL */
984 freeze_tell = freeze_tell_config; /* Can be set by ACL */
985 fake_response = OK; /* Can be set by ACL */
986 #ifdef WITH_CONTENT_SCAN
987 no_mbox_unspool = FALSE; /* Can be set by ACL */
989 submission_mode = FALSE; /* Can be set by ACL */
990 suppress_local_fixups = FALSE; /* Can be set by ACL */
991 active_local_from_check = local_from_check; /* Can be set by ACL */
992 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
993 sender_address = NULL;
994 submission_name = NULL; /* Can be set by ACL */
995 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
996 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
997 sender_verified_list = NULL; /* No senders verified */
998 memset(sender_address_cache, 0, sizeof(sender_address_cache));
999 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1000 authenticated_sender = NULL;
1001 #ifdef EXPERIMENTAL_BRIGHTMAIL
1003 bmi_verdicts = NULL;
1005 #ifdef EXPERIMENTAL_DOMAINKEYS
1008 #ifdef EXPERIMENTAL_SPF
1009 spf_header_comment = NULL;
1010 spf_received = NULL;
1012 spf_smtp_comment = NULL;
1014 body_linecount = body_zerocount = 0;
1016 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1017 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1018 /* Note that ratelimiters_conn persists across resets. */
1020 /* Reset message ACL variables */
1024 /* The message body variables use malloc store. They may be set if this is
1025 not the first message in an SMTP session and the previous message caused them
1026 to be referenced in an ACL. */
1028 if (message_body != NULL)
1030 store_free(message_body);
1031 message_body = NULL;
1034 if (message_body_end != NULL)
1036 store_free(message_body_end);
1037 message_body_end = NULL;
1040 /* Warning log messages are also saved in malloc store. They are saved to avoid
1041 repetition in the same message, but it seems right to repeat them for different
1044 while (acl_warn_logged != NULL)
1046 string_item *this = acl_warn_logged;
1047 acl_warn_logged = acl_warn_logged->next;
1056 /*************************************************
1057 * Initialize for incoming batched SMTP message *
1058 *************************************************/
1060 /* This function is called from smtp_setup_msg() in the case when
1061 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1062 of messages in one file with SMTP commands between them. All errors must be
1063 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1064 relevant. After an error on a sender, or an invalid recipient, the remainder
1065 of the message is skipped. The value of received_protocol is already set.
1068 Returns: > 0 message successfully started (reached DATA)
1069 = 0 QUIT read or end of file reached
1070 < 0 should not occur
1074 smtp_setup_batch_msg(void)
1077 void *reset_point = store_get(0);
1079 /* Save the line count at the start of each transaction - single commands
1080 like HELO and RSET count as whole transactions. */
1082 bsmtp_transaction_linecount = receive_linecount;
1084 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1086 smtp_reset(reset_point); /* Reset for start of message */
1088 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1089 value. The values are 2 larger than the required yield of the function. */
1094 uschar *recipient = NULL;
1095 int start, end, sender_domain, recipient_domain;
1097 switch(smtp_read_command(FALSE))
1099 /* The HELO/EHLO commands set sender_address_helo if they have
1100 valid data; otherwise they are ignored, except that they do
1101 a reset of the state. */
1106 check_helo(smtp_cmd_data);
1110 smtp_reset(reset_point);
1111 bsmtp_transaction_linecount = receive_linecount;
1115 /* The MAIL FROM command requires an address as an operand. All we
1116 do here is to parse it for syntactic correctness. The form "<>" is
1117 a special case which converts into an empty string. The start/end
1118 pointers in the original are not used further for this address, as
1119 it is the canonical extracted address which is all that is kept. */
1122 if (sender_address != NULL)
1123 /* The function moan_smtp_batch() does not return. */
1124 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1126 if (smtp_cmd_data[0] == 0)
1127 /* The function moan_smtp_batch() does not return. */
1128 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1130 /* Reset to start of message */
1132 smtp_reset(reset_point);
1134 /* Apply SMTP rewrite */
1136 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1137 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1138 US"", global_rewrite_rules) : smtp_cmd_data;
1140 /* Extract the address; the TRUE flag allows <> as valid */
1143 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1146 if (raw_sender == NULL)
1147 /* The function moan_smtp_batch() does not return. */
1148 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1150 sender_address = string_copy(raw_sender);
1152 /* Qualify unqualified sender addresses if permitted to do so. */
1154 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1156 if (allow_unqualified_sender)
1158 sender_address = rewrite_address_qualify(sender_address, FALSE);
1159 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1160 "and rewritten\n", raw_sender);
1162 /* The function moan_smtp_batch() does not return. */
1163 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1169 /* The RCPT TO command requires an address as an operand. All we do
1170 here is to parse it for syntactic correctness. There may be any number
1171 of RCPT TO commands, specifying multiple senders. We build them all into
1172 a data structure that is in argc/argv format. The start/end values
1173 given by parse_extract_address are not used, as we keep only the
1174 extracted address. */
1177 if (sender_address == NULL)
1178 /* The function moan_smtp_batch() does not return. */
1179 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1181 if (smtp_cmd_data[0] == 0)
1182 /* The function moan_smtp_batch() does not return. */
1183 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1185 /* Check maximum number allowed */
1187 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1188 /* The function moan_smtp_batch() does not return. */
1189 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1190 recipients_max_reject? "552": "452");
1192 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1193 recipient address */
1195 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1196 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1197 global_rewrite_rules) : smtp_cmd_data;
1199 /* rfc821_domains = TRUE; << no longer needed */
1200 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1201 &recipient_domain, FALSE);
1202 /* rfc821_domains = FALSE; << no longer needed */
1204 if (recipient == NULL)
1205 /* The function moan_smtp_batch() does not return. */
1206 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1208 /* If the recipient address is unqualified, qualify it if permitted. Then
1209 add it to the list of recipients. */
1211 if (recipient_domain == 0)
1213 if (allow_unqualified_recipient)
1215 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1217 recipient = rewrite_address_qualify(recipient, TRUE);
1219 /* The function moan_smtp_batch() does not return. */
1220 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1223 receive_add_recipient(recipient, -1);
1227 /* The DATA command is legal only if it follows successful MAIL FROM
1228 and RCPT TO commands. This function is complete when a valid DATA
1229 command is encountered. */
1232 if (sender_address == NULL || recipients_count <= 0)
1234 /* The function moan_smtp_batch() does not return. */
1235 if (sender_address == NULL)
1236 moan_smtp_batch(smtp_cmd_buffer,
1237 "503 MAIL FROM:<sender> command must precede DATA");
1239 moan_smtp_batch(smtp_cmd_buffer,
1240 "503 RCPT TO:<recipient> must precede DATA");
1244 done = 3; /* DATA successfully achieved */
1245 message_ended = END_NOTENDED; /* Indicate in middle of message */
1250 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1257 bsmtp_transaction_linecount = receive_linecount;
1268 /* The function moan_smtp_batch() does not return. */
1269 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1274 /* The function moan_smtp_batch() does not return. */
1275 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1280 /* The function moan_smtp_batch() does not return. */
1281 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1286 return done - 2; /* Convert yield values */
1292 /*************************************************
1293 * Start an SMTP session *
1294 *************************************************/
1296 /* This function is called at the start of an SMTP session. Thereafter,
1297 smtp_setup_msg() is called to initiate each separate message. This
1298 function does host-specific testing, and outputs the banner line.
1301 Returns: FALSE if the session can not continue; something has
1302 gone wrong, or the connection to the host is blocked
1306 smtp_start_session(void)
1310 uschar *user_msg, *log_msg;
1314 smtp_connection_start = time(NULL);
1315 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1316 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1319 /* Default values for certain variables */
1321 helo_seen = esmtp = helo_accept_junk = FALSE;
1322 smtp_mailcmd_count = 0;
1323 count_nonmail = TRUE_UNSET;
1324 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1325 smtp_delay_mail = smtp_rlm_base;
1326 auth_advertised = FALSE;
1327 pipelining_advertised = FALSE;
1328 pipelining_enable = TRUE;
1329 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1331 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1333 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1334 authentication settings from -oMaa to remain in force. */
1336 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1337 authenticated_by = NULL;
1340 tls_cipher = tls_peerdn = NULL;
1341 tls_advertised = FALSE;
1344 /* Reset ACL connection variables */
1348 /* Allow for trailing 0 in the command and data buffers. */
1350 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1351 if (smtp_cmd_buffer == NULL)
1352 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1353 "malloc() failed for SMTP command buffer");
1354 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1356 /* For batched input, the protocol setting can be overridden from the
1357 command line by a trusted caller. */
1359 if (smtp_batched_input)
1361 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1364 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1365 reset later if any of EHLO/AUTH/STARTTLS are received. */
1369 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1371 /* Set up the buffer for inputting using direct read() calls, and arrange to
1372 call the local functions instead of the standard C ones. */
1374 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1375 if (smtp_inbuffer == NULL)
1376 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1377 receive_getc = smtp_getc;
1378 receive_ungetc = smtp_ungetc;
1379 receive_feof = smtp_feof;
1380 receive_ferror = smtp_ferror;
1381 smtp_inptr = smtp_inend = smtp_inbuffer;
1382 smtp_had_eof = smtp_had_error = 0;
1384 /* Set up the message size limit; this may be host-specific */
1386 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1387 if (expand_string_message != NULL)
1389 if (thismessage_size_limit == -1)
1390 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1391 "%s", expand_string_message);
1393 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1394 "%s", expand_string_message);
1395 smtp_closedown(US"Temporary local problem - please try later");
1399 /* When a message is input locally via the -bs or -bS options, sender_host_
1400 unknown is set unless -oMa was used to force an IP address, in which case it
1401 is checked like a real remote connection. When -bs is used from inetd, this
1402 flag is not set, causing the sending host to be checked. The code that deals
1403 with IP source routing (if configured) is never required for -bs or -bS and
1404 the flag sender_host_notsocket is used to suppress it.
1406 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1407 reserve for certain hosts and/or networks. */
1409 if (!sender_host_unknown)
1412 BOOL reserved_host = FALSE;
1414 /* Look up IP options (source routing info) on the socket if this is not an
1415 -oMa "host", and if any are found, log them and drop the connection.
1417 Linux (and others now, see below) is different to everyone else, so there
1418 has to be some conditional compilation here. Versions of Linux before 2.1.15
1419 used a structure whose name was "options". Somebody finally realized that
1420 this name was silly, and it got changed to "ip_options". I use the
1421 newer name here, but there is a fudge in the script that sets up os.h
1422 to define a macro in older Linux systems.
1424 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1425 glibc 2, which has chosen ip_opts for the structure name. This is now
1426 really a glibc thing rather than a Linux thing, so the condition name
1427 has been changed to reflect this. It is relevant also to GNU/Hurd.
1429 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1430 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1431 a special macro defined in the os.h file.
1433 Some DGUX versions on older hardware appear not to support IP options at
1434 all, so there is now a general macro which can be set to cut out this
1437 How to do this properly in IPv6 is not yet known. */
1439 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1441 #ifdef GLIBC_IP_OPTIONS
1442 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1447 #elif defined DARWIN_IP_OPTIONS
1453 if (!host_checking && !sender_host_notsocket)
1456 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1457 struct ip_options *ipopt = store_get(optlen);
1459 struct ip_opts ipoptblock;
1460 struct ip_opts *ipopt = &ipoptblock;
1461 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1463 struct ipoption ipoptblock;
1464 struct ipoption *ipopt = &ipoptblock;
1465 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1468 /* Occasional genuine failures of getsockopt() have been seen - for
1469 example, "reset by peer". Therefore, just log and give up on this
1470 call, unless the error is ENOPROTOOPT. This error is given by systems
1471 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1472 of writing. So for that error, carry on - we just can't do an IP options
1475 DEBUG(D_receive) debug_printf("checking for IP options\n");
1477 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1480 if (errno != ENOPROTOOPT)
1482 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1483 host_and_ident(FALSE), strerror(errno));
1484 smtp_printf("451 SMTP service not available\r\n");
1489 /* Deal with any IP options that are set. On the systems I have looked at,
1490 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1491 more logging data than will fit in big_buffer. Nevertheless, after somebody
1492 questioned this code, I've added in some paranoid checking. */
1494 else if (optlen > 0)
1496 uschar *p = big_buffer;
1497 uschar *pend = big_buffer + big_buffer_size;
1498 uschar *opt, *adptr;
1500 struct in_addr addr;
1503 uschar *optstart = (uschar *)(ipopt->__data);
1505 uschar *optstart = (uschar *)(ipopt->ip_opts);
1507 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1510 DEBUG(D_receive) debug_printf("IP options exist\n");
1512 Ustrcpy(p, "IP options on incoming call:");
1515 for (opt = optstart; opt != NULL &&
1516 opt < (uschar *)(ipopt) + optlen;)
1530 if (!string_format(p, pend-p, " %s [@%s",
1531 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1533 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1535 inet_ntoa(ipopt->ip_dst)))
1537 inet_ntoa(ipopt->ipopt_dst)))
1545 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1547 while (optcount-- > 0)
1549 memcpy(&addr, adptr, sizeof(addr));
1550 if (!string_format(p, pend - p - 1, "%s%s",
1551 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1557 adptr += sizeof(struct in_addr);
1566 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1569 for (i = 0; i < opt[1]; i++)
1571 sprintf(CS p, "%2.2x ", opt[i]);
1582 log_write(0, LOG_MAIN, "%s", big_buffer);
1584 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1586 log_write(0, LOG_MAIN|LOG_REJECT,
1587 "connection from %s refused (IP options)", host_and_ident(FALSE));
1589 smtp_printf("554 SMTP service not available\r\n");
1593 /* Length of options = 0 => there are no options */
1595 else DEBUG(D_receive) debug_printf("no IP options found\n");
1597 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1599 /* Set keep-alive in socket options. The option is on by default. This
1600 setting is an attempt to get rid of some hanging connections that stick in
1601 read() when the remote end (usually a dialup) goes away. */
1603 if (smtp_accept_keepalive && !sender_host_notsocket)
1604 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1606 /* If the current host matches host_lookup, set the name by doing a
1607 reverse lookup. On failure, sender_host_name will be NULL and
1608 host_lookup_failed will be TRUE. This may or may not be serious - optional
1611 if (verify_check_host(&host_lookup) == OK)
1613 (void)host_name_lookup();
1614 host_build_sender_fullhost();
1617 /* Delay this until we have the full name, if it is looked up. */
1619 set_process_info("handling incoming connection from %s",
1620 host_and_ident(FALSE));
1622 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1623 smtps port for use with older style SSL MTAs. */
1626 if (tls_on_connect &&
1627 tls_server_start(tls_require_ciphers,
1628 gnutls_require_mac, gnutls_require_kx, gnutls_require_proto) != OK)
1632 /* Test for explicit connection rejection */
1634 if (verify_check_host(&host_reject_connection) == OK)
1636 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1637 "from %s (host_reject_connection)", host_and_ident(FALSE));
1638 smtp_printf("554 SMTP service not available\r\n");
1642 /* Test with TCP Wrappers if so configured. There is a problem in that
1643 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1644 such as disks dying. In these cases, it is desirable to reject with a 4xx
1645 error instead of a 5xx error. There isn't a "right" way to detect such
1646 problems. The following kludge is used: errno is zeroed before calling
1647 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1648 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1651 #ifdef USE_TCP_WRAPPERS
1653 if (!hosts_ctl("exim",
1654 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1655 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1656 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1658 if (errno == 0 || errno == ENOENT)
1660 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1661 log_write(L_connection_reject,
1662 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1663 "(tcp wrappers)", host_and_ident(FALSE));
1664 smtp_printf("554 SMTP service not available\r\n");
1668 int save_errno = errno;
1669 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1670 "errno value %d\n", save_errno);
1671 log_write(L_connection_reject,
1672 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1673 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1674 smtp_printf("451 Temporary local problem - please try later\r\n");
1680 /* Check for reserved slots. The value of smtp_accept_count has already been
1681 incremented to include this process. */
1683 if (smtp_accept_max > 0 &&
1684 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
1686 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1688 log_write(L_connection_reject,
1689 LOG_MAIN, "temporarily refused connection from %s: not in "
1690 "reserve list: connected=%d max=%d reserve=%d%s",
1691 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
1692 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1693 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1694 "please try again later\r\n", smtp_active_hostname);
1697 reserved_host = TRUE;
1700 /* If a load level above which only messages from reserved hosts are
1701 accepted is set, check the load. For incoming calls via the daemon, the
1702 check is done in the superior process if there are no reserved hosts, to
1703 save a fork. In all cases, the load average will already be available
1704 in a global variable at this point. */
1706 if (smtp_load_reserve >= 0 &&
1707 load_average > smtp_load_reserve &&
1709 verify_check_host(&smtp_reserve_hosts) != OK)
1711 log_write(L_connection_reject,
1712 LOG_MAIN, "temporarily refused connection from %s: not in "
1713 "reserve list and load average = %.2f", host_and_ident(FALSE),
1714 (double)load_average/1000.0);
1715 smtp_printf("421 %s: Too much load; please try again later\r\n",
1716 smtp_active_hostname);
1720 /* Determine whether unqualified senders or recipients are permitted
1721 for this host. Unfortunately, we have to do this every time, in order to
1722 set the flags so that they can be inspected when considering qualifying
1723 addresses in the headers. For a site that permits no qualification, this
1724 won't take long, however. */
1726 allow_unqualified_sender =
1727 verify_check_host(&sender_unqualified_hosts) == OK;
1729 allow_unqualified_recipient =
1730 verify_check_host(&recipient_unqualified_hosts) == OK;
1732 /* Determine whether HELO/EHLO is required for this host. The requirement
1733 can be hard or soft. */
1735 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1737 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1739 /* Determine whether this hosts is permitted to send syntactic junk
1740 after a HELO or EHLO command. */
1742 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1745 /* For batch SMTP input we are now done. */
1747 if (smtp_batched_input) return TRUE;
1749 /* Run the ACL if it exists */
1752 if (acl_smtp_connect != NULL)
1755 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1759 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1764 /* Output the initial message for a two-way SMTP connection. It may contain
1765 newlines, which then cause a multi-line response to be given. */
1767 code = US"220"; /* Default status code */
1768 esc = US""; /* Default extended status code */
1769 esclen = 0; /* Length of esc */
1771 if (user_msg == NULL)
1773 s = expand_string(smtp_banner);
1775 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1776 "failed: %s", smtp_banner, expand_string_message);
1782 smtp_message_code(&code, &codelen, &s, NULL);
1786 esclen = codelen - 4;
1790 /* Remove any terminating newlines; might as well remove trailing space too */
1793 while (p > s && isspace(p[-1])) p--;
1796 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1797 is all contained in a single IP packet. The original code wrote out the
1798 greeting using several calls to fprint/fputc, and on busy servers this could
1799 cause it to be split over more than one packet - which caused CC:Mail to fall
1800 over when it got the second part of the greeting after sending its first
1801 command. Sigh. To try to avoid this, build the complete greeting message
1802 first, and output it in one fell swoop. This gives a better chance of it
1803 ending up as a single packet. */
1805 ss = store_get(size);
1809 do /* At least once, in case we have an empty string */
1812 uschar *linebreak = Ustrchr(p, '\n');
1813 ss = string_cat(ss, &size, &ptr, code, 3);
1814 if (linebreak == NULL)
1817 ss = string_cat(ss, &size, &ptr, US" ", 1);
1821 len = linebreak - p;
1822 ss = string_cat(ss, &size, &ptr, US"-", 1);
1824 ss = string_cat(ss, &size, &ptr, esc, esclen);
1825 ss = string_cat(ss, &size, &ptr, p, len);
1826 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1828 if (linebreak != NULL) p++;
1832 ss[ptr] = 0; /* string_cat leaves room for this */
1834 /* Before we write the banner, check that there is no input pending, unless
1835 this synchronisation check is disabled. */
1839 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1840 "synchronization error (input sent without waiting for greeting): "
1841 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1842 string_printing(smtp_inptr));
1843 smtp_printf("554 SMTP synchronization error\r\n");
1847 /* Now output the banner */
1849 smtp_printf("%s", ss);
1857 /*************************************************
1858 * Handle SMTP syntax and protocol errors *
1859 *************************************************/
1861 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1862 to do so. Then transmit the error response. The return value depends on the
1863 number of syntax and protocol errors in this SMTP session.
1866 type error type, given as a log flag bit
1867 code response code; <= 0 means don't send a response
1868 data data to reflect in the response (can be NULL)
1869 errmess the error message
1871 Returns: -1 limit of syntax/protocol errors NOT exceeded
1872 +1 limit of syntax/protocol errors IS exceeded
1874 These values fit in with the values of the "done" variable in the main
1875 processing loop in smtp_setup_msg(). */
1878 synprot_error(int type, int code, uschar *data, uschar *errmess)
1882 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1883 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1884 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1886 if (++synprot_error_count > smtp_max_synprot_errors)
1889 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1890 "syntax or protocol errors (last command was \"%s\")",
1891 host_and_ident(FALSE), smtp_cmd_buffer);
1896 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1897 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1899 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1908 /*************************************************
1909 * Log incomplete transactions *
1910 *************************************************/
1912 /* This function is called after a transaction has been aborted by RSET, QUIT,
1913 connection drops or other errors. It logs the envelope information received
1914 so far in order to preserve address verification attempts.
1916 Argument: string to indicate what aborted the transaction
1921 incomplete_transaction_log(uschar *what)
1923 if (sender_address == NULL || /* No transaction in progress */
1924 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1927 /* Build list of recipients for logging */
1929 if (recipients_count > 0)
1932 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1933 for (i = 0; i < recipients_count; i++)
1934 raw_recipients[i] = recipients_list[i].address;
1935 raw_recipients_count = recipients_count;
1938 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1939 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1945 /*************************************************
1946 * Send SMTP response, possibly multiline *
1947 *************************************************/
1949 /* There are, it seems, broken clients out there that cannot handle multiline
1950 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1951 output nothing for non-final calls, and only the first line for anything else.
1954 code SMTP code, may involve extended status codes
1955 codelen length of smtp code; if > 4 there's an ESC
1956 final FALSE if the last line isn't the final line
1957 msg message text, possibly containing newlines
1963 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
1968 if (!final && no_multiline_responses) return;
1973 esclen = codelen - 4;
1976 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
1977 have had the same. Note: this code is also present in smtp_printf(). It would
1978 be tidier to have it only in one place, but when it was added, it was easier to
1979 do it that way, so as not to have to mess with the code for the RCPT command,
1980 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
1982 if (rcpt_in_progress)
1984 if (rcpt_smtp_response == NULL)
1985 rcpt_smtp_response = string_copy(msg);
1986 else if (rcpt_smtp_response_same &&
1987 Ustrcmp(rcpt_smtp_response, msg) != 0)
1988 rcpt_smtp_response_same = FALSE;
1989 rcpt_in_progress = FALSE;
1992 /* Not output the message, splitting it up into multiple lines if necessary. */
1996 uschar *nl = Ustrchr(msg, '\n');
1999 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2002 else if (nl[1] == 0 || no_multiline_responses)
2004 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2005 (int)(nl - msg), msg);
2010 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2012 while (isspace(*msg)) msg++;
2020 /*************************************************
2021 * Parse user SMTP message *
2022 *************************************************/
2024 /* This function allows for user messages overriding the response code details
2025 by providing a suitable response code string at the start of the message
2026 user_msg. Check the message for starting with a response code and optionally an
2027 extended status code. If found, check that the first digit is valid, and if so,
2028 change the code pointer and length to use the replacement. An invalid code
2029 causes a panic log; in this case, if the log messages is the same as the user
2030 message, we must also adjust the value of the log message to show the code that
2031 is actually going to be used (the original one).
2033 This function is global because it is called from receive.c as well as within
2036 Note that the code length returned includes the terminating whitespace
2037 character, which is always included in the regex match.
2040 code SMTP code, may involve extended status codes
2041 codelen length of smtp code; if > 4 there's an ESC
2043 log_msg optional log message, to be adjusted with the new SMTP code
2049 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2054 if (msg == NULL || *msg == NULL) return;
2056 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2057 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2060 if ((*msg)[0] != (*code)[0])
2062 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2063 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2064 if (log_msg != NULL && *log_msg == *msg)
2065 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2070 *codelen = ovector[1]; /* Includes final space */
2072 *msg += ovector[1]; /* Chop the code off the message */
2079 /*************************************************
2080 * Handle an ACL failure *
2081 *************************************************/
2083 /* This function is called when acl_check() fails. As well as calls from within
2084 this module, it is called from receive.c for an ACL after DATA. It sorts out
2085 logging the incident, and sets up the error response. A message containing
2086 newlines is turned into a multiline SMTP response, but for logging, only the
2089 There's a table of default permanent failure response codes to use in
2090 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2091 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2092 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2093 state, because there are broken clients that try VRFY before RCPT. A 5xx
2094 response should be given only when the address is positively known to be
2095 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2098 From Exim 4.63, it is possible to override the response code details by
2099 providing a suitable response code string at the start of the message provided
2100 in user_msg. The code's first digit is checked for validity.
2103 where where the ACL was called from
2105 user_msg a message that can be included in an SMTP response
2106 log_msg a message for logging
2108 Returns: 0 in most cases
2109 2 if the failure code was FAIL_DROP, in which case the
2110 SMTP connection should be dropped (this value fits with the
2111 "done" variable in smtp_setup_msg() below)
2115 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2117 BOOL drop = rc == FAIL_DROP;
2121 uschar *sender_info = US"";
2123 #ifdef WITH_CONTENT_SCAN
2124 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2126 (where == ACL_WHERE_PREDATA)? US"DATA" :
2127 (where == ACL_WHERE_DATA)? US"after DATA" :
2128 (smtp_cmd_data == NULL)?
2129 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2130 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2132 if (drop) rc = FAIL;
2134 /* Set the default SMTP code, and allow a user message to change it. */
2136 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2137 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2139 /* We used to have sender_address here; however, there was a bug that was not
2140 updating sender_address after a rewrite during a verify. When this bug was
2141 fixed, sender_address at this point became the rewritten address. I'm not sure
2142 this is what should be logged, so I've changed to logging the unrewritten
2143 address to retain backward compatibility. */
2145 #ifndef WITH_CONTENT_SCAN
2146 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2148 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2151 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
2152 sender_address_unrewritten : sender_address);
2155 /* If there's been a sender verification failure with a specific message, and
2156 we have not sent a response about it yet, do so now, as a preliminary line for
2157 failures, but not defers. However, always log it for defer, and log it for fail
2158 unless the sender_verify_fail log selector has been turned off. */
2160 if (sender_verified_failed != NULL &&
2161 !testflag(sender_verified_failed, af_sverify_told))
2163 BOOL save_rcpt_in_progress = rcpt_in_progress;
2164 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2166 setflag(sender_verified_failed, af_sverify_told);
2168 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2169 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2170 host_and_ident(TRUE),
2171 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2172 sender_verified_failed->address,
2173 (sender_verified_failed->message == NULL)? US"" :
2174 string_sprintf(": %s", sender_verified_failed->message));
2176 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2177 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2178 testflag(sender_verified_failed, af_verify_pmfail)?
2179 "Postmaster verification failed while checking <%s>\n%s\n"
2180 "Several RFCs state that you are required to have a postmaster\n"
2181 "mailbox for each mail domain. This host does not accept mail\n"
2182 "from domains whose servers reject the postmaster address."
2184 testflag(sender_verified_failed, af_verify_nsfail)?
2185 "Callback setup failed while verifying <%s>\n%s\n"
2186 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2187 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2188 "RFC requirements, and stops you from receiving standard bounce\n"
2189 "messages. This host does not accept mail from domains whose servers\n"
2192 "Verification failed for <%s>\n%s",
2193 sender_verified_failed->address,
2194 sender_verified_failed->user_message));
2196 rcpt_in_progress = save_rcpt_in_progress;
2199 /* Sort out text for logging */
2201 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2202 lognl = Ustrchr(log_msg, '\n');
2203 if (lognl != NULL) *lognl = 0;
2205 /* Send permanent failure response to the command, but the code used isn't
2206 always a 5xx one - see comments at the start of this function. If the original
2207 rc was FAIL_DROP we drop the connection and yield 2. */
2209 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2210 US"Administrative prohibition" : user_msg);
2212 /* Send temporary failure response to the command. Don't give any details,
2213 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2214 verb, and for a header verify when smtp_return_error_details is set.
2216 This conditional logic is all somewhat of a mess because of the odd
2217 interactions between temp_details and return_error_details. One day it should
2218 be re-implemented in a tidier fashion. */
2222 if (acl_temp_details && user_msg != NULL)
2224 if (smtp_return_error_details &&
2225 sender_verified_failed != NULL &&
2226 sender_verified_failed->message != NULL)
2228 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2230 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2233 smtp_respond(smtp_code, codelen, TRUE,
2234 US"Temporary local problem - please try later");
2237 /* Log the incident to the logs that are specified by log_reject_target
2238 (default main, reject). This can be empty to suppress logging of rejections. If
2239 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2240 is closing if required and return 2. */
2242 if (log_reject_target != 0)
2243 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2244 host_and_ident(TRUE),
2245 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2247 if (!drop) return 0;
2249 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2250 smtp_get_connection_info());
2257 /*************************************************
2258 * Verify HELO argument *
2259 *************************************************/
2261 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2262 matched. It is also called from ACL processing if verify = helo is used and
2263 verification was not previously tried (i.e. helo_try_verify_hosts was not
2264 matched). The result of its processing is to set helo_verified and
2265 helo_verify_failed. These variables should both be FALSE for this function to
2268 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2269 for IPv6 ::ffff: literals.
2272 Returns: TRUE if testing was completed;
2273 FALSE on a temporary failure
2277 smtp_verify_helo(void)
2281 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2284 if (sender_helo_name == NULL)
2286 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2289 /* Deal with the case of -bs without an IP address */
2291 else if (sender_host_address == NULL)
2293 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2294 helo_verified = TRUE;
2297 /* Deal with the more common case when there is a sending IP address */
2299 else if (sender_helo_name[0] == '[')
2301 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2302 Ustrlen(sender_host_address)) == 0;
2307 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2308 helo_verified = Ustrncmp(sender_helo_name + 1,
2309 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2314 { if (helo_verified) debug_printf("matched host address\n"); }
2317 /* Do a reverse lookup if one hasn't already given a positive or negative
2318 response. If that fails, or the name doesn't match, try checking with a forward
2323 if (sender_host_name == NULL && !host_lookup_failed)
2324 yield = host_name_lookup() != DEFER;
2326 /* If a host name is known, check it and all its aliases. */
2328 if (sender_host_name != NULL)
2330 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2334 HDEBUG(D_receive) debug_printf("matched host name\n");
2338 uschar **aliases = sender_host_aliases;
2339 while (*aliases != NULL)
2341 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2342 if (helo_verified) break;
2347 debug_printf("matched alias %s\n", *(--aliases));
2352 /* Final attempt: try a forward lookup of the helo name */
2358 h.name = sender_helo_name;
2362 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2364 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2365 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2370 if (Ustrcmp(hh->address, sender_host_address) == 0)
2372 helo_verified = TRUE;
2374 debug_printf("IP address for %s matches calling address\n",
2384 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2391 /*************************************************
2392 * Send user response message *
2393 *************************************************/
2395 /* This function is passed a default response code and a user message. It calls
2396 smtp_message_code() to check and possibly modify the response code, and then
2397 calls smtp_respond() to transmit the response. I put this into a function
2398 just to avoid a lot of repetition.
2401 code the response code
2402 user_msg the user message
2408 smtp_user_msg(uschar *code, uschar *user_msg)
2411 smtp_message_code(&code, &len, &user_msg, NULL);
2412 smtp_respond(code, len, TRUE, user_msg);
2418 /*************************************************
2419 * Initialize for SMTP incoming message *
2420 *************************************************/
2422 /* This function conducts the initial dialogue at the start of an incoming SMTP
2423 message, and builds a list of recipients. However, if the incoming message
2424 is part of a batch (-bS option) a separate function is called since it would
2425 be messy having tests splattered about all over this function. This function
2426 therefore handles the case where interaction is occurring. The input and output
2427 files are set up in smtp_in and smtp_out.
2429 The global recipients_list is set to point to a vector of recipient_item
2430 blocks, whose number is given by recipients_count. This is extended by the
2431 receive_add_recipient() function. The global variable sender_address is set to
2432 the sender's address. The yield is +1 if a message has been successfully
2433 started, 0 if a QUIT command was encountered or the connection was refused from
2434 the particular host, or -1 if the connection was lost.
2438 Returns: > 0 message successfully started (reached DATA)
2439 = 0 QUIT read or end of file reached or call refused
2444 smtp_setup_msg(void)
2447 BOOL toomany = FALSE;
2448 BOOL discarded = FALSE;
2449 BOOL last_was_rej_mail = FALSE;
2450 BOOL last_was_rcpt = FALSE;
2451 void *reset_point = store_get(0);
2453 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2455 /* Reset for start of new message. We allow one RSET not to be counted as a
2456 nonmail command, for those MTAs that insist on sending it between every
2457 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2458 TLS between messages (an Exim client may do this if it has messages queued up
2459 for the host). Note: we do NOT reset AUTH at this point. */
2461 smtp_reset(reset_point);
2462 message_ended = END_NOTSTARTED;
2464 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2465 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2466 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2468 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2471 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2473 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2475 /* Batched SMTP is handled in a different function. */
2477 if (smtp_batched_input) return smtp_setup_batch_msg();
2479 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2480 value. The values are 2 larger than the required yield of the function. */
2485 uschar *etrn_command;
2486 uschar *etrn_serialize_key;
2488 uschar *log_msg, *smtp_code;
2489 uschar *user_msg = NULL;
2490 uschar *recipient = NULL;
2491 uschar *hello = NULL;
2492 uschar *set_id = NULL;
2494 BOOL was_rej_mail = FALSE;
2495 BOOL was_rcpt = FALSE;
2496 void (*oldsignal)(int);
2498 int start, end, sender_domain, recipient_domain;
2503 switch(smtp_read_command(TRUE))
2505 /* The AUTH command is not permitted to occur inside a transaction, and may
2506 occur successfully only once per connection. Actually, that isn't quite
2507 true. When TLS is started, all previous information about a connection must
2508 be discarded, so a new AUTH is permitted at that time.
2510 AUTH may only be used when it has been advertised. However, it seems that
2511 there are clients that send AUTH when it hasn't been advertised, some of
2512 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2513 So there's a get-out that allows this to happen.
2515 AUTH is initially labelled as a "nonmail command" so that one occurrence
2516 doesn't get counted. We change the label here so that multiple failing
2517 AUTHS will eventually hit the nonmail threshold. */
2521 authentication_failed = TRUE;
2522 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2524 if (!auth_advertised && !allow_auth_unadvertised)
2526 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2527 US"AUTH command used when not advertised");
2530 if (sender_host_authenticated != NULL)
2532 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2533 US"already authenticated");
2536 if (sender_address != NULL)
2538 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2539 US"not permitted in mail transaction");
2545 if (acl_smtp_auth != NULL)
2547 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2550 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2555 /* Find the name of the requested authentication mechanism. */
2558 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
2560 if (!isalnum(c) && c != '-' && c != '_')
2562 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2563 US"invalid character in authentication mechanism name");
2569 /* If not at the end of the line, we must be at white space. Terminate the
2570 name and move the pointer on to any data that may be present. */
2572 if (*smtp_cmd_data != 0)
2574 *smtp_cmd_data++ = 0;
2575 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
2578 /* Search for an authentication mechanism which is configured for use
2579 as a server and which has been advertised (unless, sigh, allow_auth_
2580 unadvertised is set). */
2582 for (au = auths; au != NULL; au = au->next)
2584 if (strcmpic(s, au->public_name) == 0 && au->server &&
2585 (au->advertised || allow_auth_unadvertised)) break;
2590 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2591 string_sprintf("%s authentication mechanism not supported", s));
2595 /* Run the checking code, passing the remainder of the command line as
2596 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2597 it as the only set numerical variable. The authenticator may set $auth<n>
2598 and also set other numeric variables. The $auth<n> variables are preferred
2599 nowadays; the numerical variables remain for backwards compatibility.
2601 Afterwards, have a go at expanding the set_id string, even if
2602 authentication failed - for bad passwords it can be useful to log the
2603 userid. On success, require set_id to expand and exist, and put it in
2604 authenticated_id. Save this in permanent store, as the working store gets
2605 reset at HELO, RSET, etc. */
2607 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2609 expand_nlength[0] = 0; /* $0 contains nothing */
2611 c = (au->info->servercode)(au, smtp_cmd_data);
2612 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2613 expand_nmax = -1; /* Reset numeric variables */
2614 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2616 /* The value of authenticated_id is stored in the spool file and printed in
2617 log lines. It must not contain binary zeros or newline characters. In
2618 normal use, it never will, but when playing around or testing, this error
2619 can (did) happen. To guard against this, ensure that the id contains only
2620 printing characters. */
2622 if (set_id != NULL) set_id = string_printing(set_id);
2624 /* For the non-OK cases, set up additional logging data if set_id
2629 if (set_id != NULL && *set_id != 0)
2630 set_id = string_sprintf(" (set_id=%s)", set_id);
2634 /* Switch on the result */
2639 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2641 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2642 sender_host_authenticated = au->name;
2643 authentication_failed = FALSE;
2645 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2646 ((sender_host_address != NULL)? pnlocal : 0);
2647 s = ss = US"235 Authentication succeeded";
2648 authenticated_by = au;
2652 /* Authentication succeeded, but we failed to expand the set_id string.
2653 Treat this as a temporary error. */
2655 auth_defer_msg = expand_string_message;
2659 s = string_sprintf("435 Unable to authenticate at present%s",
2660 auth_defer_user_msg);
2661 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2662 set_id, auth_defer_msg);
2666 s = ss = US"501 Invalid base64 data";
2670 s = ss = US"501 Authentication cancelled";
2674 s = ss = US"553 Initial data not expected";
2678 s = US"535 Incorrect authentication data";
2679 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2683 s = US"435 Internal error";
2684 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2685 "check", set_id, c);
2689 smtp_printf("%s\r\n", s);
2691 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2692 au->name, host_and_ident(FALSE), ss);
2694 break; /* AUTH_CMD */
2696 /* The HELO/EHLO commands are permitted to appear in the middle of a
2697 session as well as at the beginning. They have the effect of a reset in
2698 addition to their other functions. Their absence at the start cannot be
2699 taken to be an error.
2703 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2704 or 502 failure replies MUST be returned as appropriate. The SMTP
2705 server MUST stay in the same state after transmitting these replies
2706 that it was in before the EHLO was received.
2708 Therefore, we do not do the reset until after checking the command for
2709 acceptability. This change was made for Exim release 4.11. Previously
2710 it did the reset first. */
2723 HELO_EHLO: /* Common code for HELO and EHLO */
2724 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2725 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2727 /* Reject the HELO if its argument was invalid or non-existent. A
2728 successful check causes the argument to be saved in malloc store. */
2730 if (!check_helo(smtp_cmd_data))
2732 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2734 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2735 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2736 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2737 string_printing(smtp_cmd_argument));
2739 if (++synprot_error_count > smtp_max_synprot_errors)
2741 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2742 "syntax or protocol errors (last command was \"%s\")",
2743 host_and_ident(FALSE), smtp_cmd_buffer);
2750 /* If sender_host_unknown is true, we have got here via the -bs interface,
2751 not called from inetd. Otherwise, we are running an IP connection and the
2752 host address will be set. If the helo name is the primary name of this
2753 host and we haven't done a reverse lookup, force one now. If helo_required
2754 is set, ensure that the HELO name matches the actual host. If helo_verify
2755 is set, do the same check, but softly. */
2757 if (!sender_host_unknown)
2759 BOOL old_helo_verified = helo_verified;
2760 uschar *p = smtp_cmd_data;
2762 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2765 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2766 because otherwise the log can be confusing. */
2768 if (sender_host_name == NULL &&
2769 (deliver_domain = sender_helo_name, /* set $domain */
2770 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2771 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2772 (void)host_name_lookup();
2774 /* Rebuild the fullhost info to include the HELO name (and the real name
2775 if it was looked up.) */
2777 host_build_sender_fullhost(); /* Rebuild */
2778 set_process_info("handling%s incoming connection from %s",
2779 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2781 /* Verify if configured. This doesn't give much security, but it does
2782 make some people happy to be able to do it. If helo_required is set,
2783 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2784 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2785 now obsolescent, since the verification can now be requested selectively
2788 helo_verified = helo_verify_failed = FALSE;
2789 if (helo_required || helo_verify)
2791 BOOL tempfail = !smtp_verify_helo();
2796 smtp_printf("%d %s argument does not match calling host\r\n",
2797 tempfail? 451 : 550, hello);
2798 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2799 tempfail? "temporarily " : "",
2800 hello, sender_helo_name, host_and_ident(FALSE));
2801 helo_verified = old_helo_verified;
2802 break; /* End of HELO/EHLO processing */
2804 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2805 "helo_try_verify_hosts\n", hello);
2810 #ifdef EXPERIMENTAL_SPF
2811 /* set up SPF context */
2812 spf_init(sender_helo_name, sender_host_address);
2815 /* Apply an ACL check if one is defined; afterwards, recheck
2816 synchronization in case the client started sending in a delay. */
2818 if (acl_smtp_helo != NULL)
2820 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2823 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2824 sender_helo_name = NULL;
2825 host_build_sender_fullhost(); /* Rebuild */
2828 else if (!check_sync()) goto SYNC_FAILURE;
2831 /* Generate an OK reply. The default string includes the ident if present,
2832 and also the IP address if present. Reflecting back the ident is intended
2833 as a deterrent to mail forgers. For maximum efficiency, and also because
2834 some broken systems expect each response to be in a single packet, arrange
2835 that the entire reply is sent in one write(). */
2837 auth_advertised = FALSE;
2838 pipelining_advertised = FALSE;
2840 tls_advertised = FALSE;
2843 smtp_code = US"250 "; /* Default response code plus space*/
2844 if (user_msg == NULL)
2846 s = string_sprintf("%.3s %s Hello %s%s%s",
2848 smtp_active_hostname,
2849 (sender_ident == NULL)? US"" : sender_ident,
2850 (sender_ident == NULL)? US"" : US" at ",
2851 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2856 if (sender_host_address != NULL)
2858 s = string_cat(s, &size, &ptr, US" [", 2);
2859 s = string_cat(s, &size, &ptr, sender_host_address,
2860 Ustrlen(sender_host_address));
2861 s = string_cat(s, &size, &ptr, US"]", 1);
2865 /* A user-supplied EHLO greeting may not contain more than one line. Note
2866 that the code returned by smtp_message_code() includes the terminating
2867 whitespace character. */
2873 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
2874 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
2875 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
2877 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
2878 "newlines: message truncated: %s", string_printing(s));
2885 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2887 /* If we received EHLO, we must create a multiline response which includes
2888 the functions supported. */
2894 /* I'm not entirely happy with this, as an MTA is supposed to check
2895 that it has enough room to accept a message of maximum size before
2896 it sends this. However, there seems little point in not sending it.
2897 The actual size check happens later at MAIL FROM time. By postponing it
2898 till then, VRFY and EXPN can be used after EHLO when space is short. */
2900 if (thismessage_size_limit > 0)
2902 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
2903 thismessage_size_limit);
2904 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2908 s = string_cat(s, &size, &ptr, smtp_code, 3);
2909 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
2912 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2913 clean; if it has an 8-bit character in its hand, it just sends it. It
2914 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2915 However, some users want this option simply in order to stop MUAs
2916 mangling messages that contain top-bit-set characters. It is therefore
2917 provided as an option. */
2919 if (accept_8bitmime)
2921 s = string_cat(s, &size, &ptr, smtp_code, 3);
2922 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
2925 /* Advertise ETRN if there's an ACL checking whether a host is
2926 permitted to issue it; a check is made when any host actually tries. */
2928 if (acl_smtp_etrn != NULL)
2930 s = string_cat(s, &size, &ptr, smtp_code, 3);
2931 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
2934 /* Advertise EXPN if there's an ACL checking whether a host is
2935 permitted to issue it; a check is made when any host actually tries. */
2937 if (acl_smtp_expn != NULL)
2939 s = string_cat(s, &size, &ptr, smtp_code, 3);
2940 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
2943 /* Exim is quite happy with pipelining, so let the other end know that
2944 it is safe to use it, unless advertising is disabled. */
2946 if (pipelining_enable &&
2947 verify_check_host(&pipelining_advertise_hosts) == OK)
2949 s = string_cat(s, &size, &ptr, smtp_code, 3);
2950 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
2951 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2952 pipelining_advertised = TRUE;
2955 /* If any server authentication mechanisms are configured, advertise
2956 them if the current host is in auth_advertise_hosts. The problem with
2957 advertising always is that some clients then require users to
2958 authenticate (and aren't configurable otherwise) even though it may not
2959 be necessary (e.g. if the host is in host_accept_relay).
2961 RFC 2222 states that SASL mechanism names contain only upper case
2962 letters, so output the names in upper case, though we actually recognize
2963 them in either case in the AUTH command. */
2967 if (verify_check_host(&auth_advertise_hosts) == OK)
2971 for (au = auths; au != NULL; au = au->next)
2973 if (au->server && (au->advertise_condition == NULL ||
2974 expand_check_condition(au->advertise_condition, au->name,
2975 US"authenticator")))
2980 s = string_cat(s, &size, &ptr, smtp_code, 3);
2981 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
2983 auth_advertised = TRUE;
2986 s = string_cat(s, &size, &ptr, US" ", 1);
2987 s = string_cat(s, &size, &ptr, au->public_name,
2988 Ustrlen(au->public_name));
2989 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2990 au->advertised = TRUE;
2992 else au->advertised = FALSE;
2994 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2998 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2999 if it has been included in the binary, and the host matches
3000 tls_advertise_hosts. We must *not* advertise if we are already in a
3001 secure connection. */
3004 if (tls_active < 0 &&
3005 verify_check_host(&tls_advertise_hosts) != FAIL)
3007 s = string_cat(s, &size, &ptr, smtp_code, 3);
3008 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3009 tls_advertised = TRUE;
3013 /* Finish off the multiline reply with one that is always available. */
3015 s = string_cat(s, &size, &ptr, smtp_code, 3);
3016 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3019 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3025 if (tls_active >= 0) (void)tls_write(s, ptr); else
3028 (void)fwrite(s, 1, ptr, smtp_out);
3032 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3033 memmove(cr, cr + 1, (ptr--) - (cr - s));
3034 debug_printf("SMTP>> %s", s);
3038 /* Reset the protocol and the state, abandoning any previous message. */
3040 received_protocol = (esmtp?
3042 ((sender_host_authenticated != NULL)? pauthed : 0) +
3043 ((tls_active >= 0)? pcrpted : 0)]
3045 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
3047 ((sender_host_address != NULL)? pnlocal : 0);
3049 smtp_reset(reset_point);
3051 break; /* HELO/EHLO */
3054 /* The MAIL command requires an address as an operand. All we do
3055 here is to parse it for syntactic correctness. The form "<>" is
3056 a special case which converts into an empty string. The start/end
3057 pointers in the original are not used further for this address, as
3058 it is the canonical extracted address which is all that is kept. */
3062 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3063 was_rej_mail = TRUE; /* Reset if accepted */
3065 if (helo_required && !helo_seen)
3067 smtp_printf("503 HELO or EHLO required\r\n");
3068 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3069 "HELO/EHLO given", host_and_ident(FALSE));
3073 if (sender_address != NULL)
3075 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3076 US"sender already given");
3080 if (smtp_cmd_data[0] == 0)
3082 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3083 US"MAIL must have an address operand");
3087 /* Check to see if the limit for messages per connection would be
3088 exceeded by accepting further messages. */
3090 if (smtp_accept_max_per_connection > 0 &&
3091 smtp_mailcmd_count > smtp_accept_max_per_connection)
3093 smtp_printf("421 too many messages in this connection\r\n");
3094 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3095 "messages in one connection", host_and_ident(TRUE));
3099 /* Reset for start of message - even if this is going to fail, we
3100 obviously need to throw away any previous data. */
3102 smtp_reset(reset_point);
3104 sender_data = recipient_data = NULL;
3106 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3110 uschar *name, *value, *end;
3111 unsigned long int size;
3113 if (!extract_option(&name, &value)) break;
3115 /* Handle SIZE= by reading the value. We don't do the check till later,
3116 in order to be able to log the sender address on failure. */
3118 if (strcmpic(name, US"SIZE") == 0 &&
3119 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
3121 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3123 message_size = (int)size;
3126 /* If this session was initiated with EHLO and accept_8bitmime is set,
3127 Exim will have indicated that it supports the BODY=8BITMIME option. In
3128 fact, it does not support this according to the RFCs, in that it does not
3129 take any special action for forwarding messages containing 8-bit
3130 characters. That is why accept_8bitmime is not the default setting, but
3131 some sites want the action that is provided. We recognize both "8BITMIME"
3132 and "7BIT" as body types, but take no action. */
3134 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
3135 (strcmpic(value, US"8BITMIME") == 0 ||
3136 strcmpic(value, US"7BIT") == 0)) {}
3138 /* Handle the AUTH extension. If the value given is not "<>" and either
3139 the ACL says "yes" or there is no ACL but the sending host is
3140 authenticated, we set it up as the authenticated sender. However, if the
3141 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3142 the condition is met. The value of AUTH is an xtext, which means that +,
3143 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3146 else if (strcmpic(name, US"AUTH") == 0)
3148 if (Ustrcmp(value, "<>") != 0)
3153 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3155 /* Put back terminator overrides for error message */
3158 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3159 US"invalid data for AUTH");
3163 if (acl_smtp_mailauth == NULL)
3165 ignore_msg = US"client not authenticated";
3166 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3170 ignore_msg = US"rejected by ACL";
3171 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3172 &user_msg, &log_msg);
3178 if (authenticated_by == NULL ||
3179 authenticated_by->mail_auth_condition == NULL ||
3180 expand_check_condition(authenticated_by->mail_auth_condition,
3181 authenticated_by->name, US"authenticator"))
3182 break; /* Accept the AUTH */
3184 ignore_msg = US"server_mail_auth_condition failed";
3185 if (authenticated_id != NULL)
3186 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3187 ignore_msg, authenticated_id);
3192 authenticated_sender = NULL;
3193 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3194 value, host_and_ident(TRUE), ignore_msg);
3197 /* Should only get DEFER or ERROR here. Put back terminator
3198 overrides for error message */
3203 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3210 /* Unknown option. Stick back the terminator characters and break
3211 the loop. An error for a malformed address will occur. */
3221 /* If we have passed the threshold for rate limiting, apply the current
3222 delay, and update it for next time, provided this is a limited host. */
3224 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3225 verify_check_host(&smtp_ratelimit_hosts) == OK)
3227 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3228 smtp_delay_mail/1000.0);
3229 millisleep((int)smtp_delay_mail);
3230 smtp_delay_mail *= smtp_rlm_factor;
3231 if (smtp_delay_mail > (double)smtp_rlm_limit)
3232 smtp_delay_mail = (double)smtp_rlm_limit;
3235 /* Now extract the address, first applying any SMTP-time rewriting. The
3236 TRUE flag allows "<>" as a sender address. */
3238 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3239 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3240 global_rewrite_rules) : smtp_cmd_data;
3242 /* rfc821_domains = TRUE; << no longer needed */
3244 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3246 /* rfc821_domains = FALSE; << no longer needed */
3248 if (raw_sender == NULL)
3250 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3254 sender_address = raw_sender;
3256 /* If there is a configured size limit for mail, check that this message
3257 doesn't exceed it. The check is postponed to this point so that the sender
3260 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3262 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3263 log_write(L_size_reject,
3264 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3265 "message too big: size%s=%d max=%d",
3267 host_and_ident(TRUE),
3268 (message_size == INT_MAX)? ">" : "",
3270 thismessage_size_limit);
3271 sender_address = NULL;
3275 /* Check there is enough space on the disk unless configured not to.
3276 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3277 plus the current message - i.e. we accept the message only if it won't
3278 reduce the space below the threshold. Add 5000 to the size to allow for
3279 overheads such as the Received: line and storing of recipients, etc.
3280 By putting the check here, even when SIZE is not given, it allow VRFY
3281 and EXPN etc. to be used when space is short. */
3283 if (!receive_check_fs(
3284 (smtp_check_spool_space && message_size >= 0)?
3285 message_size + 5000 : 0))
3287 smtp_printf("452 Space shortage, please try later\r\n");
3288 sender_address = NULL;
3292 /* If sender_address is unqualified, reject it, unless this is a locally
3293 generated message, or the sending host or net is permitted to send
3294 unqualified addresses - typically local machines behaving as MUAs -
3295 in which case just qualify the address. The flag is set above at the start
3296 of the SMTP connection. */
3298 if (sender_domain == 0 && sender_address[0] != 0)
3300 if (allow_unqualified_sender)
3302 sender_domain = Ustrlen(sender_address) + 1;
3303 sender_address = rewrite_address_qualify(sender_address, FALSE);
3304 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3309 smtp_printf("501 %s: sender address must contain a domain\r\n",
3311 log_write(L_smtp_syntax_error,
3312 LOG_MAIN|LOG_REJECT,
3313 "unqualified sender rejected: <%s> %s%s",
3315 host_and_ident(TRUE),
3317 sender_address = NULL;
3322 /* Apply an ACL check if one is defined, before responding. Afterwards,
3323 when pipelining is not advertised, do another sync check in case the ACL
3324 delayed and the client started sending in the meantime. */
3326 if (acl_smtp_mail == NULL) rc = OK; else
3328 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3329 if (rc == OK && !pipelining_advertised && !check_sync())
3333 if (rc == OK || rc == DISCARD)
3335 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3336 else smtp_user_msg(US"250", user_msg);
3337 smtp_delay_rcpt = smtp_rlr_base;
3338 recipients_discarded = (rc == DISCARD);
3339 was_rej_mail = FALSE;
3343 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3344 sender_address = NULL;
3349 /* The RCPT command requires an address as an operand. There may be any
3350 number of RCPT commands, specifying multiple recipients. We build them all
3351 into a data structure. The start/end values given by parse_extract_address
3352 are not used, as we keep only the extracted address. */
3357 was_rcpt = rcpt_in_progress = TRUE;
3359 /* There must be a sender address; if the sender was rejected and
3360 pipelining was advertised, we assume the client was pipelining, and do not
3361 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3362 get the same treatment. */
3364 if (sender_address == NULL)
3366 if (pipelining_advertised && last_was_rej_mail)
3368 smtp_printf("503 sender not yet given\r\n");
3369 was_rej_mail = TRUE;
3373 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3374 US"sender not yet given");
3375 was_rcpt = FALSE; /* Not a valid RCPT */
3381 /* Check for an operand */
3383 if (smtp_cmd_data[0] == 0)
3385 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3386 US"RCPT must have an address operand");
3391 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3392 as a recipient address */
3394 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3395 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3396 global_rewrite_rules) : smtp_cmd_data;
3398 /* rfc821_domains = TRUE; << no longer needed */
3399 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3400 &recipient_domain, FALSE);
3401 /* rfc821_domains = FALSE; << no longer needed */
3403 if (recipient == NULL)
3405 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3410 /* If the recipient address is unqualified, reject it, unless this is a
3411 locally generated message. However, unqualified addresses are permitted
3412 from a configured list of hosts and nets - typically when behaving as
3413 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3414 really. The flag is set at the start of the SMTP connection.
3416 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3417 assumed this meant "reserved local part", but the revision of RFC 821 and
3418 friends now makes it absolutely clear that it means *mailbox*. Consequently
3419 we must always qualify this address, regardless. */
3421 if (recipient_domain == 0)
3423 if (allow_unqualified_recipient ||
3424 strcmpic(recipient, US"postmaster") == 0)
3426 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3428 recipient_domain = Ustrlen(recipient) + 1;
3429 recipient = rewrite_address_qualify(recipient, TRUE);
3434 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3436 log_write(L_smtp_syntax_error,
3437 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3438 "<%s> %s%s", recipient, host_and_ident(TRUE),
3444 /* Check maximum allowed */
3446 if (rcpt_count > recipients_max && recipients_max > 0)
3448 if (recipients_max_reject)
3451 smtp_printf("552 too many recipients\r\n");
3453 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3454 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3459 smtp_printf("452 too many recipients\r\n");
3461 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3462 "temporarily rejected: sender=<%s> %s", sender_address,
3463 host_and_ident(TRUE));
3470 /* If we have passed the threshold for rate limiting, apply the current
3471 delay, and update it for next time, provided this is a limited host. */
3473 if (rcpt_count > smtp_rlr_threshold &&
3474 verify_check_host(&smtp_ratelimit_hosts) == OK)
3476 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3477 smtp_delay_rcpt/1000.0);
3478 millisleep((int)smtp_delay_rcpt);
3479 smtp_delay_rcpt *= smtp_rlr_factor;
3480 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3481 smtp_delay_rcpt = (double)smtp_rlr_limit;
3484 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3485 for them. Otherwise, check the access control list for this recipient. As
3486 there may be a delay in this, re-check for a synchronization error
3487 afterwards, unless pipelining was advertised. */
3489 if (recipients_discarded) rc = DISCARD; else
3491 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
3493 if (rc == OK && !pipelining_advertised && !check_sync())
3497 /* The ACL was happy */
3501 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3502 else smtp_user_msg(US"250", user_msg);
3503 receive_add_recipient(recipient, -1);
3506 /* The recipient was discarded */
3508 else if (rc == DISCARD)
3510 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3511 else smtp_user_msg(US"250", user_msg);
3514 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3515 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3516 (sender_address_unrewritten != NULL)?
3517 sender_address_unrewritten : sender_address,
3518 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3519 (log_msg == NULL)? US"" : US": ",
3520 (log_msg == NULL)? US"" : log_msg);
3523 /* Either the ACL failed the address, or it was deferred. */
3527 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3528 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3533 /* The DATA command is legal only if it follows successful MAIL FROM
3534 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3535 not counted as a protocol error if it follows RCPT (which must have been
3536 rejected if there are no recipients.) This function is complete when a
3537 valid DATA command is encountered.
3539 Note concerning the code used: RFC 2821 says this:
3541 - If there was no MAIL, or no RCPT, command, or all such commands
3542 were rejected, the server MAY return a "command out of sequence"
3543 (503) or "no valid recipients" (554) reply in response to the
3546 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3547 because it is the same whether pipelining is in use or not.
3549 If all the RCPT commands that precede DATA provoked the same error message
3550 (often indicating some kind of system error), it is helpful to include it
3551 with the DATA rejection (an idea suggested by Tony Finch). */
3555 if (!discarded && recipients_count <= 0)
3557 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
3559 uschar *code = US"503";
3560 int len = Ustrlen(rcpt_smtp_response);
3561 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
3563 /* Responses from smtp_printf() will have \r\n on the end */
3564 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
3565 rcpt_smtp_response[len-2] = 0;
3566 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
3568 if (pipelining_advertised && last_was_rcpt)
3569 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
3571 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3572 US"valid RCPT command must precede DATA");
3576 if (toomany && recipients_max_reject)
3578 sender_address = NULL; /* This will allow a new MAIL without RSET */
3579 sender_address_unrewritten = NULL;
3580 smtp_printf("554 Too many recipients\r\n");
3584 /* If there is an ACL, re-check the synchronization afterwards, since the
3585 ACL may have delayed. */
3587 if (acl_smtp_predata == NULL) rc = OK; else
3589 enable_dollar_recipients = TRUE;
3590 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3592 enable_dollar_recipients = FALSE;
3593 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
3598 if (user_msg == NULL)
3599 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3600 else smtp_user_msg(US"354", user_msg);
3602 message_ended = END_NOTENDED; /* Indicate in middle of data */
3605 /* Either the ACL failed the address, or it was deferred. */
3608 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3614 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3616 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3622 /* rfc821_domains = TRUE; << no longer needed */
3623 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
3624 &recipient_domain, FALSE);
3625 /* rfc821_domains = FALSE; << no longer needed */
3627 if (address == NULL)
3628 s = string_sprintf("501 %s", errmess);
3631 address_item *addr = deliver_make_addr(address, FALSE);
3632 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3633 -1, -1, NULL, NULL, NULL))
3636 s = string_sprintf("250 <%s> is deliverable", address);
3640 s = (addr->user_message != NULL)?
3641 string_sprintf("451 <%s> %s", address, addr->user_message) :
3642 string_sprintf("451 Cannot resolve <%s> at this time", address);
3646 s = (addr->user_message != NULL)?
3647 string_sprintf("550 <%s> %s", address, addr->user_message) :
3648 string_sprintf("550 <%s> is not deliverable", address);
3649 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3650 smtp_cmd_argument, host_and_ident(TRUE));
3655 smtp_printf("%s\r\n", s);
3662 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3664 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3667 BOOL save_log_testing_mode = log_testing_mode;
3668 address_test_mode = log_testing_mode = TRUE;
3669 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
3670 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3672 address_test_mode = FALSE;
3673 log_testing_mode = save_log_testing_mode; /* true for -bh */
3682 if (!tls_advertised)
3684 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3685 US"STARTTLS command used when not advertised");
3689 /* Apply an ACL check if one is defined */
3691 if (acl_smtp_starttls != NULL)
3693 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3697 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3702 /* RFC 2487 is not clear on when this command may be sent, though it
3703 does state that all information previously obtained from the client
3704 must be discarded if a TLS session is started. It seems reasonble to
3705 do an implied RSET when STARTTLS is received. */
3707 incomplete_transaction_log(US"STARTTLS");
3708 smtp_reset(reset_point);
3710 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3712 /* Attempt to start up a TLS session, and if successful, discard all
3713 knowledge that was obtained previously. At least, that's what the RFC says,
3714 and that's what happens by default. However, in order to work round YAEB,
3715 there is an option to remember the esmtp state. Sigh.
3717 We must allow for an extra EHLO command and an extra AUTH command after
3718 STARTTLS that don't add to the nonmail command count. */
3720 if ((rc = tls_server_start(tls_require_ciphers, gnutls_require_mac,
3721 gnutls_require_kx, gnutls_require_proto)) == OK)
3723 if (!tls_remember_esmtp)
3724 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3725 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3726 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3727 if (sender_helo_name != NULL)
3729 store_free(sender_helo_name);
3730 sender_helo_name = NULL;
3731 host_build_sender_fullhost(); /* Rebuild */
3732 set_process_info("handling incoming TLS connection from %s",
3733 host_and_ident(FALSE));
3735 received_protocol = (esmtp?
3736 protocols[pextend + pcrpted +
3737 ((sender_host_authenticated != NULL)? pauthed : 0)]
3739 protocols[pnormal + pcrpted])
3741 ((sender_host_address != NULL)? pnlocal : 0);
3743 sender_host_authenticated = NULL;
3744 authenticated_id = NULL;
3745 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3746 DEBUG(D_tls) debug_printf("TLS active\n");
3747 break; /* Successful STARTTLS */
3750 /* Some local configuration problem was discovered before actually trying
3751 to do a TLS handshake; give a temporary error. */
3753 else if (rc == DEFER)
3755 smtp_printf("454 TLS currently unavailable\r\n");
3759 /* Hard failure. Reject everything except QUIT or closed connection. One
3760 cause for failure is a nested STARTTLS, in which case tls_active remains
3761 set, but we must still reject all incoming commands. */
3763 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3766 switch(smtp_read_command(FALSE))
3769 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3770 smtp_get_connection_info());
3775 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3776 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3777 smtp_get_connection_info());
3782 smtp_printf("554 Security failure\r\n");
3791 /* The ACL for QUIT is provided for gathering statistical information or
3792 similar; it does not affect the response code, but it can supply a custom
3797 incomplete_transaction_log(US"QUIT");
3799 if (acl_smtp_quit != NULL)
3801 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit,&user_msg,&log_msg);
3803 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3807 if (user_msg == NULL)
3808 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3810 smtp_respond(US"221", 3, TRUE, user_msg);
3817 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3818 smtp_get_connection_info());
3824 incomplete_transaction_log(US"RSET");
3825 smtp_reset(reset_point);
3827 smtp_printf("250 Reset OK\r\n");
3828 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3834 smtp_printf("250 OK\r\n");
3838 /* Show ETRN/EXPN/VRFY if there's
3839 an ACL for checking hosts; if actually used, a check will be done for
3844 smtp_printf("214-Commands supported:\r\n");
3848 Ustrcat(buffer, " AUTH");
3850 Ustrcat(buffer, " STARTTLS");
3852 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3853 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3854 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3855 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3856 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3857 smtp_printf("214%s\r\n", buffer);
3863 incomplete_transaction_log(US"connection lost");
3864 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3866 /* Don't log by default unless in the middle of a message, as some mailers
3867 just drop the call rather than sending QUIT, and it clutters up the logs.
3870 if (sender_address != NULL || recipients_count > 0)
3871 log_write(L_lost_incoming_connection,
3873 "unexpected %s while reading SMTP command from %s%s",
3874 sender_host_unknown? "EOF" : "disconnection",
3875 host_and_ident(FALSE), smtp_read_error);
3877 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3878 smtp_get_connection_info(), smtp_read_error);
3886 if (sender_address != NULL)
3888 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3889 US"ETRN is not permitted inside a transaction");
3893 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
3894 host_and_ident(FALSE));
3896 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
3899 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3903 /* Compute the serialization key for this command. */
3905 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
3907 /* If a command has been specified for running as a result of ETRN, we
3908 permit any argument to ETRN. If not, only the # standard form is permitted,
3909 since that is strictly the only kind of ETRN that can be implemented
3910 according to the RFC. */
3912 if (smtp_etrn_command != NULL)
3916 etrn_command = smtp_etrn_command;
3917 deliver_domain = smtp_cmd_data;
3918 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3919 US"ETRN processing", &error);
3920 deliver_domain = NULL;
3923 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3925 smtp_printf("458 Internal failure\r\n");
3930 /* Else set up to call Exim with the -R option. */
3934 if (*smtp_cmd_data++ != '#')
3936 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3937 US"argument must begin with #");
3940 etrn_command = US"exim -R";
3941 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3945 /* If we are host-testing, don't actually do anything. */
3951 debug_printf("ETRN command is: %s\n", etrn_command);
3952 debug_printf("ETRN command execution skipped\n");
3954 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3955 else smtp_user_msg(US"250", user_msg);
3960 /* If ETRN queue runs are to be serialized, check the database to
3961 ensure one isn't already running. */
3963 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3965 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
3969 /* Fork a child process and run the command. We don't want to have to
3970 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3971 forking. It should be set that way anyway for external incoming SMTP,
3972 but we save and restore to be tidy. If serialization is required, we
3973 actually run the command in yet another process, so we can wait for it
3974 to complete and then remove the serialization lock. */
3976 oldsignal = signal(SIGCHLD, SIG_IGN);
3978 if ((pid = fork()) == 0)
3980 smtp_input = FALSE; /* This process is not associated with the */
3981 (void)fclose(smtp_in); /* SMTP call any more. */
3982 (void)fclose(smtp_out);
3984 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3986 /* If not serializing, do the exec right away. Otherwise, fork down
3987 into another process. */
3989 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3991 DEBUG(D_exec) debug_print_argv(argv);
3992 exim_nullstd(); /* Ensure std{in,out,err} exist */
3993 execv(CS argv[0], (char *const *)argv);
3994 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3995 etrn_command, strerror(errno));
3996 _exit(EXIT_FAILURE); /* paranoia */
3999 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4000 is, we are in the first subprocess, after forking again. All we can do
4001 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4002 complete, before removing the serialization. */
4005 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4006 "failed: %s", strerror(errno));
4010 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4012 (void)wait(&status);
4013 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4017 enq_end(etrn_serialize_key);
4018 _exit(EXIT_SUCCESS);
4021 /* Back in the top level SMTP process. Check that we started a subprocess
4022 and restore the signal state. */
4026 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4028 smtp_printf("458 Unable to fork process\r\n");
4029 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4033 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4034 else smtp_user_msg(US"250", user_msg);
4037 signal(SIGCHLD, oldsignal);
4042 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4043 US"unexpected argument data");
4047 /* This currently happens only for NULLs, but could be extended. */
4050 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
4051 US"NULL character(s) present (shown as '?')");
4052 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
4058 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
4059 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
4060 c = smtp_inend - smtp_inptr;
4061 if (c > 150) c = 150;
4063 incomplete_transaction_log(US"sync failure");
4064 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
4065 "(next input sent too soon: pipelining was%s advertised): "
4066 "rejected \"%s\" %s next input=\"%s\"",
4067 pipelining_advertised? "" : " not",
4068 smtp_cmd_buffer, host_and_ident(TRUE),
4069 string_printing(smtp_inptr));
4070 smtp_printf("554 SMTP synchronization error\r\n");
4071 done = 1; /* Pretend eof - drops connection */
4075 case TOO_MANY_NONMAIL_CMD:
4076 s = smtp_cmd_buffer;
4077 while (*s != 0 && !isspace(*s)) s++;
4078 incomplete_transaction_log(US"too many non-mail commands");
4079 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4080 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
4081 s - smtp_cmd_buffer, smtp_cmd_buffer);
4082 smtp_printf("554 Too many nonmail commands\r\n");
4083 done = 1; /* Pretend eof - drops connection */
4088 if (unknown_command_count++ >= smtp_max_unknown_commands)
4090 log_write(L_smtp_syntax_error, LOG_MAIN,
4091 "SMTP syntax error in \"%s\" %s %s",
4092 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
4093 US"unrecognized command");
4094 incomplete_transaction_log(US"unrecognized command");
4095 smtp_printf("500 Too many unrecognized commands\r\n");
4097 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4098 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
4102 done = synprot_error(L_smtp_syntax_error, 500, NULL,
4103 US"unrecognized command");
4107 /* This label is used by goto's inside loops that want to break out to
4108 the end of the command-processing loop. */
4111 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
4112 last_was_rcpt = was_rcpt; /* protocol error handling */
4116 return done - 2; /* Convert yield values */
4119 /* End of smtp_in.c */