1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.62 2007/09/28 12:21:57 tom Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2007 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. */
42 #define smtp_cmd_buffer_size 2048
44 /* Size of buffer for reading SMTP incoming packets */
46 #define in_buffer_size 8192
48 /* Structure for SMTP command list */
55 short int is_mail_cmd;
58 /* Codes for identifying commands. We order them so that those that come first
59 are those for which synchronization is always required. Checking this can help
63 /* These commands are required to be synchronized, i.e. to be the last in a
64 block of commands when pipelining. */
66 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
67 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
68 ETRN_CMD, /* This by analogy with TURN from the RFC */
69 STARTTLS_CMD, /* Required by the STARTTLS RFC */
71 /* This is a dummy to identify the non-sync commands when pipelining */
73 NON_SYNC_CMD_PIPELINING,
75 /* These commands need not be synchronized when pipelining */
77 MAIL_CMD, RCPT_CMD, RSET_CMD,
79 /* This is a dummy to identify the non-sync commands when not pipelining */
81 NON_SYNC_CMD_NON_PIPELINING,
83 /* I have been unable to find a statement about the use of pipelining
84 with AUTH, so to be on the safe side it is here, though I kind of feel
85 it should be up there with the synchronized commands. */
89 /* I'm not sure about these, but I don't think they matter. */
93 /* These are specials that don't correspond to actual commands */
95 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
96 TOO_MANY_NONMAIL_CMD };
99 /* This is a convenience macro for adding the identity of an SMTP command
100 to the circular buffer that holds a list of the last n received. */
103 smtp_connection_had[smtp_ch_index++] = n; \
104 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
107 /*************************************************
108 * Local static variables *
109 *************************************************/
111 static auth_instance *authenticated_by;
112 static BOOL auth_advertised;
114 static BOOL tls_advertised;
117 static BOOL helo_required = FALSE;
118 static BOOL helo_verify = FALSE;
119 static BOOL helo_seen;
120 static BOOL helo_accept_junk;
121 static BOOL count_nonmail;
122 static BOOL pipelining_advertised;
123 static BOOL rcpt_smtp_response_same;
124 static BOOL rcpt_in_progress;
125 static int nonmail_command_count;
126 static BOOL smtp_exit_function_called = 0;
127 static int synprot_error_count;
128 static int unknown_command_count;
129 static int sync_cmd_limit;
130 static int smtp_write_error = 0;
132 static uschar *rcpt_smtp_response;
133 static uschar *smtp_data_buffer;
134 static uschar *smtp_cmd_data;
136 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
137 final fields of all except AUTH are forced TRUE at the start of a new message
138 setup, to allow one of each between messages that is not counted as a nonmail
139 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
140 allow a new EHLO after starting up TLS.
142 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
143 counted. However, the flag is changed when AUTH is received, so that multiple
144 failing AUTHs will eventually hit the limit. After a successful AUTH, another
145 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
146 forced TRUE, to allow for the re-authentication that can happen at that point.
148 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
149 count of non-mail commands and possibly provoke an error. */
151 static smtp_cmd_list cmd_list[] = {
152 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
153 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
154 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
155 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
157 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
160 /* If you change anything above here, also fix the definitions below. */
162 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
163 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
164 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
165 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
166 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
167 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
168 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
169 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
170 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
173 static smtp_cmd_list *cmd_list_end =
174 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
176 #define CMD_LIST_RSET 0
177 #define CMD_LIST_HELO 1
178 #define CMD_LIST_EHLO 2
179 #define CMD_LIST_AUTH 3
180 #define CMD_LIST_STARTTLS 4
182 /* This list of names is used for performing the smtp_no_mail logging action.
183 It must be kept in step with the SCH_xxx enumerations. */
185 static uschar *smtp_names[] =
187 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
188 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
191 static uschar *protocols[] = {
192 US"local-smtp", /* HELO */
193 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
194 US"local-esmtp", /* EHLO */
195 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
196 US"local-esmtpa", /* EHLO->AUTH */
197 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
202 #define pcrpted 1 /* added to pextend or pnormal */
203 #define pauthed 2 /* added to pextend */
204 #define pnlocal 6 /* offset to remove "local" */
206 /* When reading SMTP from a remote host, we have to use our own versions of the
207 C input-reading functions, in order to be able to flush the SMTP output only
208 when about to read more data from the socket. This is the only way to get
209 optimal performance when the client is using pipelining. Flushing for every
210 command causes a separate packet and reply packet each time; saving all the
211 responses up (when pipelining) combines them into one packet and one response.
213 For simplicity, these functions are used for *all* SMTP input, not only when
214 receiving over a socket. However, after setting up a secure socket (SSL), input
215 is read via the OpenSSL library, and another set of functions is used instead
218 These functions are set in the receive_getc etc. variables and called with the
219 same interface as the C functions. However, since there can only ever be
220 one incoming SMTP call, we just use a single buffer and flags. There is no need
221 to implement a complicated private FILE-like structure.*/
223 static uschar *smtp_inbuffer;
224 static uschar *smtp_inptr;
225 static uschar *smtp_inend;
226 static int smtp_had_eof;
227 static int smtp_had_error;
230 /*************************************************
231 * SMTP version of getc() *
232 *************************************************/
234 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
235 it flushes the output, and refills the buffer, with a timeout. The signal
236 handler is set appropriately by the calling function. This function is not used
237 after a connection has negotated itself into an TLS/SSL state.
240 Returns: the next character or EOF
246 if (smtp_inptr >= smtp_inend)
250 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
251 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
256 /* Must put the error text in fixed store, because this might be during
257 header reading, where it releases unused store above the header. */
260 smtp_had_error = save_errno;
261 smtp_read_error = string_copy_malloc(
262 string_sprintf(" (error: %s)", strerror(save_errno)));
264 else smtp_had_eof = 1;
267 smtp_inend = smtp_inbuffer + rc;
268 smtp_inptr = smtp_inbuffer;
270 return *smtp_inptr++;
275 /*************************************************
276 * SMTP version of ungetc() *
277 *************************************************/
279 /* Puts a character back in the input buffer. Only ever
285 Returns: the character
291 *(--smtp_inptr) = ch;
298 /*************************************************
299 * SMTP version of feof() *
300 *************************************************/
302 /* Tests for a previous EOF
305 Returns: non-zero if the eof flag is set
317 /*************************************************
318 * SMTP version of ferror() *
319 *************************************************/
321 /* Tests for a previous read error, and returns with errno
322 restored to what it was when the error was detected.
325 Returns: non-zero if the error flag is set
331 errno = smtp_had_error;
332 return smtp_had_error;
337 /*************************************************
338 * Test for characters in the SMTP buffer *
339 *************************************************/
341 /* Used at the end of a message
350 return smtp_inptr < smtp_inend;
355 /*************************************************
356 * Write formatted string to SMTP channel *
357 *************************************************/
359 /* This is a separate function so that we don't have to repeat everything for
360 TLS support or debugging. It is global so that the daemon and the
361 authentication functions can use it. It does not return any error indication,
362 because major problems such as dropped connections won't show up till an output
363 flush for non-TLS connections. The smtp_fflush() function is available for
364 checking that: for convenience, TLS output errors are remembered here so that
365 they are also picked up later by smtp_fflush().
369 ... optional arguments
375 smtp_printf(char *format, ...)
382 va_start(ap, format);
383 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
385 end = big_buffer + Ustrlen(big_buffer);
386 while ((cr = Ustrchr(big_buffer, '\r')) != NULL) /* lose CRs */
387 memmove(cr, cr + 1, (end--) - cr);
388 debug_printf("SMTP>> %s", big_buffer);
391 va_start(ap, format);
392 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
394 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
395 smtp_closedown(US"Unexpected error");
396 exim_exit(EXIT_FAILURE);
400 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
401 have had the same. Note: this code is also present in smtp_respond(). It would
402 be tidier to have it only in one place, but when it was added, it was easier to
403 do it that way, so as not to have to mess with the code for the RCPT command,
404 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
406 if (rcpt_in_progress)
408 if (rcpt_smtp_response == NULL)
409 rcpt_smtp_response = string_copy(big_buffer);
410 else if (rcpt_smtp_response_same &&
411 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
412 rcpt_smtp_response_same = FALSE;
413 rcpt_in_progress = FALSE;
416 /* Now write the string */
421 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
426 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
431 /*************************************************
432 * Flush SMTP out and check for error *
433 *************************************************/
435 /* This function isn't currently used within Exim (it detects errors when it
436 tries to read the next SMTP input), but is available for use in local_scan().
437 For non-TLS connections, it flushes the output and checks for errors. For
438 TLS-connections, it checks for a previously-detected TLS write error.
441 Returns: 0 for no error; -1 after an error
447 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
448 return smtp_write_error;
453 /*************************************************
454 * SMTP command read timeout *
455 *************************************************/
457 /* Signal handler for timing out incoming SMTP commands. This attempts to
460 Argument: signal number (SIGALRM)
465 command_timeout_handler(int sig)
467 sig = sig; /* Keep picky compilers happy */
468 log_write(L_lost_incoming_connection,
469 LOG_MAIN, "SMTP command timeout on%s connection from %s",
470 (tls_active >= 0)? " TLS" : "",
471 host_and_ident(FALSE));
472 if (smtp_batched_input)
473 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
474 smtp_notquit_exit(US"command-timeout", US"421",
475 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
476 exim_exit(EXIT_FAILURE);
481 /*************************************************
483 *************************************************/
485 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
487 Argument: signal number (SIGTERM)
492 command_sigterm_handler(int sig)
494 sig = sig; /* Keep picky compilers happy */
495 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
496 if (smtp_batched_input)
497 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
498 smtp_notquit_exit(US"signal-exit", US"421",
499 US"%s: Service not available - closing connection", smtp_active_hostname);
500 exim_exit(EXIT_FAILURE);
506 /*************************************************
507 * Read one command line *
508 *************************************************/
510 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
511 There are sites that don't do this, and in any case internal SMTP probably
512 should check only for LF. Consequently, we check here for LF only. The line
513 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
514 an unknown command. The command is read into the global smtp_cmd_buffer so that
515 it is available via $smtp_command.
517 The character reading routine sets up a timeout for each block actually read
518 from the input (which may contain more than one command). We set up a special
519 signal handler that closes down the session on a timeout. Control does not
523 check_sync if TRUE, check synchronization rules if global option is TRUE
525 Returns: a code identifying the command (enumerated above)
529 smtp_read_command(BOOL check_sync)
534 BOOL hadnull = FALSE;
536 os_non_restarting_signal(SIGALRM, command_timeout_handler);
538 while ((c = (receive_getc)()) != '\n' && c != EOF)
540 if (ptr >= smtp_cmd_buffer_size)
542 os_non_restarting_signal(SIGALRM, sigalrm_handler);
550 smtp_cmd_buffer[ptr++] = c;
553 receive_linecount++; /* For BSMTP errors */
554 os_non_restarting_signal(SIGALRM, sigalrm_handler);
556 /* If hit end of file, return pseudo EOF command. Whether we have a
557 part-line already read doesn't matter, since this is an error state. */
559 if (c == EOF) return EOF_CMD;
561 /* Remove any CR and white space at the end of the line, and terminate the
564 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
565 smtp_cmd_buffer[ptr] = 0;
567 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
569 /* NULLs are not allowed in SMTP commands */
571 if (hadnull) return BADCHAR_CMD;
573 /* Scan command list and return identity, having set the data pointer
574 to the start of the actual data characters. Check for SMTP synchronization
577 for (p = cmd_list; p < cmd_list_end; p++)
579 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
580 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
581 smtp_cmd_buffer[p->len] == 0 ||
582 smtp_cmd_buffer[p->len] == ' '))
584 if (smtp_inptr < smtp_inend && /* Outstanding input */
585 p->cmd < sync_cmd_limit && /* Command should sync */
586 check_sync && /* Local flag set */
587 smtp_enforce_sync && /* Global flag set */
588 sender_host_address != NULL && /* Not local input */
589 !sender_host_notsocket) /* Really is a socket */
592 /* The variables $smtp_command and $smtp_command_argument point into the
593 unmodified input buffer. A copy of the latter is taken for actual
594 processing, so that it can be chopped up into separate parts if necessary,
595 for example, when processing a MAIL command options such as SIZE that can
596 follow the sender address. */
598 smtp_cmd_argument = smtp_cmd_buffer + p->len;
599 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
600 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
601 smtp_cmd_data = smtp_data_buffer;
603 /* Count non-mail commands from those hosts that are controlled in this
604 way. The default is all hosts. We don't waste effort checking the list
605 until we get a non-mail command, but then cache the result to save checking
606 again. If there's a DEFER while checking the host, assume it's in the list.
608 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
609 start of each incoming message by fiddling with the value in the table. */
613 if (count_nonmail == TRUE_UNSET) count_nonmail =
614 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
615 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
616 return TOO_MANY_NONMAIL_CMD;
619 /* If there is data for a command that does not expect it, generate the
622 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
626 /* Enforce synchronization for unknown commands */
628 if (smtp_inptr < smtp_inend && /* Outstanding input */
629 check_sync && /* Local flag set */
630 smtp_enforce_sync && /* Global flag set */
631 sender_host_address != NULL && /* Not local input */
632 !sender_host_notsocket) /* Really is a socket */
640 /*************************************************
641 * Recheck synchronization *
642 *************************************************/
644 /* Synchronization checks can never be perfect because a packet may be on its
645 way but not arrived when the check is done. Such checks can in any case only be
646 done when TLS is not in use. Normally, the checks happen when commands are
647 read: Exim ensures that there is no more input in the input buffer. In normal
648 cases, the response to the command will be fast, and there is no further check.
650 However, for some commands an ACL is run, and that can include delays. In those
651 cases, it is useful to do another check on the input just before sending the
652 response. This also applies at the start of a connection. This function does
653 that check by means of the select() function, as long as the facility is not
654 disabled or inappropriate. A failure of select() is ignored.
656 When there is unwanted input, we read it so that it appears in the log of the
660 Returns: TRUE if all is well; FALSE if there is input pending
668 struct timeval tzero;
670 if (!smtp_enforce_sync || sender_host_address == NULL ||
671 sender_host_notsocket || tls_active >= 0)
674 fd = fileno(smtp_in);
679 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
681 if (rc <= 0) return TRUE; /* Not ready to read */
683 if (rc < 0) return TRUE; /* End of file or error */
686 rc = smtp_inend - smtp_inptr;
687 if (rc > 150) rc = 150;
694 /*************************************************
695 * Forced closedown of call *
696 *************************************************/
698 /* This function is called from log.c when Exim is dying because of a serious
699 disaster, and also from some other places. If an incoming non-batched SMTP
700 channel is open, it swallows the rest of the incoming message if in the DATA
701 phase, sends the reply string, and gives an error to all subsequent commands
702 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
706 message SMTP reply string to send, excluding the code
712 smtp_closedown(uschar *message)
714 if (smtp_in == NULL || smtp_batched_input) return;
715 receive_swallow_smtp();
716 smtp_printf("421 %s\r\n", message);
720 switch(smtp_read_command(FALSE))
726 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
731 smtp_printf("250 Reset OK\r\n");
735 smtp_printf("421 %s\r\n", message);
744 /*************************************************
745 * Set up connection info for logging *
746 *************************************************/
748 /* This function is called when logging information about an SMTP connection.
749 It sets up appropriate source information, depending on the type of connection.
750 If sender_fullhost is NULL, we are at a very early stage of the connection;
751 just use the IP address.
754 Returns: a string describing the connection
758 smtp_get_connection_info(void)
760 uschar *hostname = (sender_fullhost == NULL)?
761 sender_host_address : sender_fullhost;
764 return string_sprintf("SMTP connection from %s", hostname);
766 if (sender_host_unknown || sender_host_notsocket)
767 return string_sprintf("SMTP connection from %s", sender_ident);
770 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
772 if ((log_extra_selector & LX_incoming_interface) != 0 &&
773 interface_address != NULL)
774 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
775 interface_address, interface_port);
777 return string_sprintf("SMTP connection from %s", hostname);
782 /*************************************************
783 * Log lack of MAIL if so configured *
784 *************************************************/
786 /* This function is called when an SMTP session ends. If the log selector
787 smtp_no_mail is set, write a log line giving some details of what has happened
795 smtp_log_no_mail(void)
800 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
806 if (sender_host_authenticated != NULL)
808 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
809 if (authenticated_id != NULL)
810 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
814 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_cipher != NULL)
815 s = string_append(s, &size, &ptr, 2, US" X=", tls_cipher);
816 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
818 s = string_append(s, &size, &ptr, 2, US" CV=",
819 tls_certificate_verified? "yes":"no");
820 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_peerdn != NULL)
821 s = string_append(s, &size, &ptr, 3, US" DN=\"",
822 string_printing(tls_peerdn), US"\"");
825 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
826 US" C=..." : US" C=";
827 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
829 if (smtp_connection_had[i] != SCH_NONE)
831 s = string_append(s, &size, &ptr, 2, sep,
832 smtp_names[smtp_connection_had[i]]);
837 for (i = 0; i < smtp_ch_index; i++)
839 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
843 if (s != NULL) s[ptr] = 0; else s = US"";
844 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
845 host_and_ident(FALSE),
846 readconf_printtime(time(NULL) - smtp_connection_start), s);
851 /*************************************************
852 * Check HELO line and set sender_helo_name *
853 *************************************************/
855 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
856 the domain name of the sending host, or an ip literal in square brackets. The
857 arrgument is placed in sender_helo_name, which is in malloc store, because it
858 must persist over multiple incoming messages. If helo_accept_junk is set, this
859 host is permitted to send any old junk (needed for some broken hosts).
860 Otherwise, helo_allow_chars can be used for rogue characters in general
861 (typically people want to let in underscores).
864 s the data portion of the line (already past any white space)
866 Returns: TRUE or FALSE
870 check_helo(uschar *s)
873 uschar *end = s + Ustrlen(s);
874 BOOL yield = helo_accept_junk;
876 /* Discard any previous helo name */
878 if (sender_helo_name != NULL)
880 store_free(sender_helo_name);
881 sender_helo_name = NULL;
884 /* Skip tests if junk is permitted. */
888 /* Allow the new standard form for IPv6 address literals, namely,
889 [IPv6:....], and because someone is bound to use it, allow an equivalent
890 IPv4 form. Allow plain addresses as well. */
897 if (strncmpic(s, US"[IPv6:", 6) == 0)
898 yield = (string_is_ip_address(s+6, NULL) == 6);
899 else if (strncmpic(s, US"[IPv4:", 6) == 0)
900 yield = (string_is_ip_address(s+6, NULL) == 4);
902 yield = (string_is_ip_address(s+1, NULL) != 0);
907 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
908 that have been configured (usually underscore - sigh). */
915 if (!isalnum(*s) && *s != '.' && *s != '-' &&
916 Ustrchr(helo_allow_chars, *s) == NULL)
926 /* Save argument if OK */
928 if (yield) sender_helo_name = string_copy_malloc(start);
936 /*************************************************
937 * Extract SMTP command option *
938 *************************************************/
940 /* This function picks the next option setting off the end of smtp_cmd_data. It
941 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
942 things that can appear there.
945 name point this at the name
946 value point this at the data string
948 Returns: TRUE if found an option
952 extract_option(uschar **name, uschar **value)
955 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
956 while (isspace(*v)) v--;
959 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
960 if (*v != '=') return FALSE;
963 while(isalpha(n[-1])) n--;
965 if (n[-1] != ' ') return FALSE;
978 /*************************************************
979 * Reset for new message *
980 *************************************************/
982 /* This function is called whenever the SMTP session is reset from
983 within either of the setup functions.
985 Argument: the stacking pool storage reset point
990 smtp_reset(void *reset_point)
992 store_reset(reset_point);
993 recipients_list = NULL;
994 rcpt_count = rcpt_defer_count = rcpt_fail_count =
995 raw_recipients_count = recipients_count = recipients_list_max = 0;
996 message_linecount = 0;
998 acl_added_headers = NULL;
999 queue_only_policy = FALSE;
1000 rcpt_smtp_response = NULL;
1001 rcpt_smtp_response_same = TRUE;
1002 rcpt_in_progress = FALSE;
1003 deliver_freeze = FALSE; /* Can be set by ACL */
1004 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1005 fake_response = OK; /* Can be set by ACL */
1006 #ifdef WITH_CONTENT_SCAN
1007 no_mbox_unspool = FALSE; /* Can be set by ACL */
1009 submission_mode = FALSE; /* Can be set by ACL */
1010 suppress_local_fixups = FALSE; /* Can be set by ACL */
1011 active_local_from_check = local_from_check; /* Can be set by ACL */
1012 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1013 sender_address = NULL;
1014 submission_name = NULL; /* Can be set by ACL */
1015 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1016 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1017 sender_verified_list = NULL; /* No senders verified */
1018 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1019 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1020 authenticated_sender = NULL;
1021 #ifdef EXPERIMENTAL_BRIGHTMAIL
1023 bmi_verdicts = NULL;
1025 #ifdef EXPERIMENTAL_DOMAINKEYS
1028 #ifdef EXPERIMENTAL_DKIM
1031 #ifdef EXPERIMENTAL_SPF
1032 spf_header_comment = NULL;
1033 spf_received = NULL;
1035 spf_smtp_comment = NULL;
1037 body_linecount = body_zerocount = 0;
1039 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1040 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1041 /* Note that ratelimiters_conn persists across resets. */
1043 /* Reset message ACL variables */
1047 /* The message body variables use malloc store. They may be set if this is
1048 not the first message in an SMTP session and the previous message caused them
1049 to be referenced in an ACL. */
1051 if (message_body != NULL)
1053 store_free(message_body);
1054 message_body = NULL;
1057 if (message_body_end != NULL)
1059 store_free(message_body_end);
1060 message_body_end = NULL;
1063 /* Warning log messages are also saved in malloc store. They are saved to avoid
1064 repetition in the same message, but it seems right to repeat them for different
1067 while (acl_warn_logged != NULL)
1069 string_item *this = acl_warn_logged;
1070 acl_warn_logged = acl_warn_logged->next;
1079 /*************************************************
1080 * Initialize for incoming batched SMTP message *
1081 *************************************************/
1083 /* This function is called from smtp_setup_msg() in the case when
1084 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1085 of messages in one file with SMTP commands between them. All errors must be
1086 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1087 relevant. After an error on a sender, or an invalid recipient, the remainder
1088 of the message is skipped. The value of received_protocol is already set.
1091 Returns: > 0 message successfully started (reached DATA)
1092 = 0 QUIT read or end of file reached
1093 < 0 should not occur
1097 smtp_setup_batch_msg(void)
1100 void *reset_point = store_get(0);
1102 /* Save the line count at the start of each transaction - single commands
1103 like HELO and RSET count as whole transactions. */
1105 bsmtp_transaction_linecount = receive_linecount;
1107 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1109 smtp_reset(reset_point); /* Reset for start of message */
1111 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1112 value. The values are 2 larger than the required yield of the function. */
1117 uschar *recipient = NULL;
1118 int start, end, sender_domain, recipient_domain;
1120 switch(smtp_read_command(FALSE))
1122 /* The HELO/EHLO commands set sender_address_helo if they have
1123 valid data; otherwise they are ignored, except that they do
1124 a reset of the state. */
1129 check_helo(smtp_cmd_data);
1133 smtp_reset(reset_point);
1134 bsmtp_transaction_linecount = receive_linecount;
1138 /* The MAIL FROM command requires an address as an operand. All we
1139 do here is to parse it for syntactic correctness. The form "<>" is
1140 a special case which converts into an empty string. The start/end
1141 pointers in the original are not used further for this address, as
1142 it is the canonical extracted address which is all that is kept. */
1145 if (sender_address != NULL)
1146 /* The function moan_smtp_batch() does not return. */
1147 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1149 if (smtp_cmd_data[0] == 0)
1150 /* The function moan_smtp_batch() does not return. */
1151 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1153 /* Reset to start of message */
1155 smtp_reset(reset_point);
1157 /* Apply SMTP rewrite */
1159 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1160 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1161 US"", global_rewrite_rules) : smtp_cmd_data;
1163 /* Extract the address; the TRUE flag allows <> as valid */
1166 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1169 if (raw_sender == NULL)
1170 /* The function moan_smtp_batch() does not return. */
1171 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1173 sender_address = string_copy(raw_sender);
1175 /* Qualify unqualified sender addresses if permitted to do so. */
1177 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1179 if (allow_unqualified_sender)
1181 sender_address = rewrite_address_qualify(sender_address, FALSE);
1182 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1183 "and rewritten\n", raw_sender);
1185 /* The function moan_smtp_batch() does not return. */
1186 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1192 /* The RCPT TO command requires an address as an operand. All we do
1193 here is to parse it for syntactic correctness. There may be any number
1194 of RCPT TO commands, specifying multiple senders. We build them all into
1195 a data structure that is in argc/argv format. The start/end values
1196 given by parse_extract_address are not used, as we keep only the
1197 extracted address. */
1200 if (sender_address == NULL)
1201 /* The function moan_smtp_batch() does not return. */
1202 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1204 if (smtp_cmd_data[0] == 0)
1205 /* The function moan_smtp_batch() does not return. */
1206 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1208 /* Check maximum number allowed */
1210 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1211 /* The function moan_smtp_batch() does not return. */
1212 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1213 recipients_max_reject? "552": "452");
1215 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1216 recipient address */
1218 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1219 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1220 global_rewrite_rules) : smtp_cmd_data;
1222 /* rfc821_domains = TRUE; << no longer needed */
1223 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1224 &recipient_domain, FALSE);
1225 /* rfc821_domains = FALSE; << no longer needed */
1227 if (recipient == NULL)
1228 /* The function moan_smtp_batch() does not return. */
1229 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1231 /* If the recipient address is unqualified, qualify it if permitted. Then
1232 add it to the list of recipients. */
1234 if (recipient_domain == 0)
1236 if (allow_unqualified_recipient)
1238 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1240 recipient = rewrite_address_qualify(recipient, TRUE);
1242 /* The function moan_smtp_batch() does not return. */
1243 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1246 receive_add_recipient(recipient, -1);
1250 /* The DATA command is legal only if it follows successful MAIL FROM
1251 and RCPT TO commands. This function is complete when a valid DATA
1252 command is encountered. */
1255 if (sender_address == NULL || recipients_count <= 0)
1257 /* The function moan_smtp_batch() does not return. */
1258 if (sender_address == NULL)
1259 moan_smtp_batch(smtp_cmd_buffer,
1260 "503 MAIL FROM:<sender> command must precede DATA");
1262 moan_smtp_batch(smtp_cmd_buffer,
1263 "503 RCPT TO:<recipient> must precede DATA");
1267 done = 3; /* DATA successfully achieved */
1268 message_ended = END_NOTENDED; /* Indicate in middle of message */
1273 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1280 bsmtp_transaction_linecount = receive_linecount;
1291 /* The function moan_smtp_batch() does not return. */
1292 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1297 /* The function moan_smtp_batch() does not return. */
1298 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1303 /* The function moan_smtp_batch() does not return. */
1304 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1309 return done - 2; /* Convert yield values */
1315 /*************************************************
1316 * Start an SMTP session *
1317 *************************************************/
1319 /* This function is called at the start of an SMTP session. Thereafter,
1320 smtp_setup_msg() is called to initiate each separate message. This
1321 function does host-specific testing, and outputs the banner line.
1324 Returns: FALSE if the session can not continue; something has
1325 gone wrong, or the connection to the host is blocked
1329 smtp_start_session(void)
1333 uschar *user_msg, *log_msg;
1337 smtp_connection_start = time(NULL);
1338 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1339 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1342 /* Default values for certain variables */
1344 helo_seen = esmtp = helo_accept_junk = FALSE;
1345 smtp_mailcmd_count = 0;
1346 count_nonmail = TRUE_UNSET;
1347 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1348 smtp_delay_mail = smtp_rlm_base;
1349 auth_advertised = FALSE;
1350 pipelining_advertised = FALSE;
1351 pipelining_enable = TRUE;
1352 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1353 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1355 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1357 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1358 authentication settings from -oMaa to remain in force. */
1360 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1361 authenticated_by = NULL;
1364 tls_cipher = tls_peerdn = NULL;
1365 tls_advertised = FALSE;
1368 /* Reset ACL connection variables */
1372 /* Allow for trailing 0 in the command and data buffers. */
1374 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1375 if (smtp_cmd_buffer == NULL)
1376 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1377 "malloc() failed for SMTP command buffer");
1378 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1380 /* For batched input, the protocol setting can be overridden from the
1381 command line by a trusted caller. */
1383 if (smtp_batched_input)
1385 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1388 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1389 reset later if any of EHLO/AUTH/STARTTLS are received. */
1393 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1395 /* Set up the buffer for inputting using direct read() calls, and arrange to
1396 call the local functions instead of the standard C ones. */
1398 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1399 if (smtp_inbuffer == NULL)
1400 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1401 receive_getc = smtp_getc;
1402 receive_ungetc = smtp_ungetc;
1403 receive_feof = smtp_feof;
1404 receive_ferror = smtp_ferror;
1405 receive_smtp_buffered = smtp_buffered;
1406 smtp_inptr = smtp_inend = smtp_inbuffer;
1407 smtp_had_eof = smtp_had_error = 0;
1409 /* Set up the message size limit; this may be host-specific */
1411 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1412 if (expand_string_message != NULL)
1414 if (thismessage_size_limit == -1)
1415 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1416 "%s", expand_string_message);
1418 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1419 "%s", expand_string_message);
1420 smtp_closedown(US"Temporary local problem - please try later");
1424 /* When a message is input locally via the -bs or -bS options, sender_host_
1425 unknown is set unless -oMa was used to force an IP address, in which case it
1426 is checked like a real remote connection. When -bs is used from inetd, this
1427 flag is not set, causing the sending host to be checked. The code that deals
1428 with IP source routing (if configured) is never required for -bs or -bS and
1429 the flag sender_host_notsocket is used to suppress it.
1431 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1432 reserve for certain hosts and/or networks. */
1434 if (!sender_host_unknown)
1437 BOOL reserved_host = FALSE;
1439 /* Look up IP options (source routing info) on the socket if this is not an
1440 -oMa "host", and if any are found, log them and drop the connection.
1442 Linux (and others now, see below) is different to everyone else, so there
1443 has to be some conditional compilation here. Versions of Linux before 2.1.15
1444 used a structure whose name was "options". Somebody finally realized that
1445 this name was silly, and it got changed to "ip_options". I use the
1446 newer name here, but there is a fudge in the script that sets up os.h
1447 to define a macro in older Linux systems.
1449 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1450 glibc 2, which has chosen ip_opts for the structure name. This is now
1451 really a glibc thing rather than a Linux thing, so the condition name
1452 has been changed to reflect this. It is relevant also to GNU/Hurd.
1454 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1455 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1456 a special macro defined in the os.h file.
1458 Some DGUX versions on older hardware appear not to support IP options at
1459 all, so there is now a general macro which can be set to cut out this
1462 How to do this properly in IPv6 is not yet known. */
1464 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1466 #ifdef GLIBC_IP_OPTIONS
1467 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1472 #elif defined DARWIN_IP_OPTIONS
1478 if (!host_checking && !sender_host_notsocket)
1481 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1482 struct ip_options *ipopt = store_get(optlen);
1484 struct ip_opts ipoptblock;
1485 struct ip_opts *ipopt = &ipoptblock;
1486 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1488 struct ipoption ipoptblock;
1489 struct ipoption *ipopt = &ipoptblock;
1490 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1493 /* Occasional genuine failures of getsockopt() have been seen - for
1494 example, "reset by peer". Therefore, just log and give up on this
1495 call, unless the error is ENOPROTOOPT. This error is given by systems
1496 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1497 of writing. So for that error, carry on - we just can't do an IP options
1500 DEBUG(D_receive) debug_printf("checking for IP options\n");
1502 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1505 if (errno != ENOPROTOOPT)
1507 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1508 host_and_ident(FALSE), strerror(errno));
1509 smtp_printf("451 SMTP service not available\r\n");
1514 /* Deal with any IP options that are set. On the systems I have looked at,
1515 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1516 more logging data than will fit in big_buffer. Nevertheless, after somebody
1517 questioned this code, I've added in some paranoid checking. */
1519 else if (optlen > 0)
1521 uschar *p = big_buffer;
1522 uschar *pend = big_buffer + big_buffer_size;
1523 uschar *opt, *adptr;
1525 struct in_addr addr;
1528 uschar *optstart = (uschar *)(ipopt->__data);
1530 uschar *optstart = (uschar *)(ipopt->ip_opts);
1532 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1535 DEBUG(D_receive) debug_printf("IP options exist\n");
1537 Ustrcpy(p, "IP options on incoming call:");
1540 for (opt = optstart; opt != NULL &&
1541 opt < (uschar *)(ipopt) + optlen;)
1555 if (!string_format(p, pend-p, " %s [@%s",
1556 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1558 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1560 inet_ntoa(ipopt->ip_dst)))
1562 inet_ntoa(ipopt->ipopt_dst)))
1570 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1572 while (optcount-- > 0)
1574 memcpy(&addr, adptr, sizeof(addr));
1575 if (!string_format(p, pend - p - 1, "%s%s",
1576 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1582 adptr += sizeof(struct in_addr);
1591 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1594 for (i = 0; i < opt[1]; i++)
1596 sprintf(CS p, "%2.2x ", opt[i]);
1607 log_write(0, LOG_MAIN, "%s", big_buffer);
1609 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1611 log_write(0, LOG_MAIN|LOG_REJECT,
1612 "connection from %s refused (IP options)", host_and_ident(FALSE));
1614 smtp_printf("554 SMTP service not available\r\n");
1618 /* Length of options = 0 => there are no options */
1620 else DEBUG(D_receive) debug_printf("no IP options found\n");
1622 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1624 /* Set keep-alive in socket options. The option is on by default. This
1625 setting is an attempt to get rid of some hanging connections that stick in
1626 read() when the remote end (usually a dialup) goes away. */
1628 if (smtp_accept_keepalive && !sender_host_notsocket)
1629 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1631 /* If the current host matches host_lookup, set the name by doing a
1632 reverse lookup. On failure, sender_host_name will be NULL and
1633 host_lookup_failed will be TRUE. This may or may not be serious - optional
1636 if (verify_check_host(&host_lookup) == OK)
1638 (void)host_name_lookup();
1639 host_build_sender_fullhost();
1642 /* Delay this until we have the full name, if it is looked up. */
1644 set_process_info("handling incoming connection from %s",
1645 host_and_ident(FALSE));
1647 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1648 smtps port for use with older style SSL MTAs. */
1651 if (tls_on_connect &&
1652 tls_server_start(tls_require_ciphers,
1653 gnutls_require_mac, gnutls_require_kx, gnutls_require_proto) != OK)
1657 /* Test for explicit connection rejection */
1659 if (verify_check_host(&host_reject_connection) == OK)
1661 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1662 "from %s (host_reject_connection)", host_and_ident(FALSE));
1663 smtp_printf("554 SMTP service not available\r\n");
1667 /* Test with TCP Wrappers if so configured. There is a problem in that
1668 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1669 such as disks dying. In these cases, it is desirable to reject with a 4xx
1670 error instead of a 5xx error. There isn't a "right" way to detect such
1671 problems. The following kludge is used: errno is zeroed before calling
1672 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1673 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1676 #ifdef USE_TCP_WRAPPERS
1678 if (!hosts_ctl("exim",
1679 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1680 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1681 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1683 if (errno == 0 || errno == ENOENT)
1685 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1686 log_write(L_connection_reject,
1687 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1688 "(tcp wrappers)", host_and_ident(FALSE));
1689 smtp_printf("554 SMTP service not available\r\n");
1693 int save_errno = errno;
1694 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1695 "errno value %d\n", save_errno);
1696 log_write(L_connection_reject,
1697 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1698 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1699 smtp_printf("451 Temporary local problem - please try later\r\n");
1705 /* Check for reserved slots. The value of smtp_accept_count has already been
1706 incremented to include this process. */
1708 if (smtp_accept_max > 0 &&
1709 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
1711 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1713 log_write(L_connection_reject,
1714 LOG_MAIN, "temporarily refused connection from %s: not in "
1715 "reserve list: connected=%d max=%d reserve=%d%s",
1716 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
1717 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1718 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1719 "please try again later\r\n", smtp_active_hostname);
1722 reserved_host = TRUE;
1725 /* If a load level above which only messages from reserved hosts are
1726 accepted is set, check the load. For incoming calls via the daemon, the
1727 check is done in the superior process if there are no reserved hosts, to
1728 save a fork. In all cases, the load average will already be available
1729 in a global variable at this point. */
1731 if (smtp_load_reserve >= 0 &&
1732 load_average > smtp_load_reserve &&
1734 verify_check_host(&smtp_reserve_hosts) != OK)
1736 log_write(L_connection_reject,
1737 LOG_MAIN, "temporarily refused connection from %s: not in "
1738 "reserve list and load average = %.2f", host_and_ident(FALSE),
1739 (double)load_average/1000.0);
1740 smtp_printf("421 %s: Too much load; please try again later\r\n",
1741 smtp_active_hostname);
1745 /* Determine whether unqualified senders or recipients are permitted
1746 for this host. Unfortunately, we have to do this every time, in order to
1747 set the flags so that they can be inspected when considering qualifying
1748 addresses in the headers. For a site that permits no qualification, this
1749 won't take long, however. */
1751 allow_unqualified_sender =
1752 verify_check_host(&sender_unqualified_hosts) == OK;
1754 allow_unqualified_recipient =
1755 verify_check_host(&recipient_unqualified_hosts) == OK;
1757 /* Determine whether HELO/EHLO is required for this host. The requirement
1758 can be hard or soft. */
1760 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1762 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1764 /* Determine whether this hosts is permitted to send syntactic junk
1765 after a HELO or EHLO command. */
1767 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1770 /* For batch SMTP input we are now done. */
1772 if (smtp_batched_input) return TRUE;
1774 /* Run the ACL if it exists */
1777 if (acl_smtp_connect != NULL)
1780 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1784 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1789 /* Output the initial message for a two-way SMTP connection. It may contain
1790 newlines, which then cause a multi-line response to be given. */
1792 code = US"220"; /* Default status code */
1793 esc = US""; /* Default extended status code */
1794 esclen = 0; /* Length of esc */
1796 if (user_msg == NULL)
1798 s = expand_string(smtp_banner);
1800 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1801 "failed: %s", smtp_banner, expand_string_message);
1807 smtp_message_code(&code, &codelen, &s, NULL);
1811 esclen = codelen - 4;
1815 /* Remove any terminating newlines; might as well remove trailing space too */
1818 while (p > s && isspace(p[-1])) p--;
1821 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1822 is all contained in a single IP packet. The original code wrote out the
1823 greeting using several calls to fprint/fputc, and on busy servers this could
1824 cause it to be split over more than one packet - which caused CC:Mail to fall
1825 over when it got the second part of the greeting after sending its first
1826 command. Sigh. To try to avoid this, build the complete greeting message
1827 first, and output it in one fell swoop. This gives a better chance of it
1828 ending up as a single packet. */
1830 ss = store_get(size);
1834 do /* At least once, in case we have an empty string */
1837 uschar *linebreak = Ustrchr(p, '\n');
1838 ss = string_cat(ss, &size, &ptr, code, 3);
1839 if (linebreak == NULL)
1842 ss = string_cat(ss, &size, &ptr, US" ", 1);
1846 len = linebreak - p;
1847 ss = string_cat(ss, &size, &ptr, US"-", 1);
1849 ss = string_cat(ss, &size, &ptr, esc, esclen);
1850 ss = string_cat(ss, &size, &ptr, p, len);
1851 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1853 if (linebreak != NULL) p++;
1857 ss[ptr] = 0; /* string_cat leaves room for this */
1859 /* Before we write the banner, check that there is no input pending, unless
1860 this synchronisation check is disabled. */
1864 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1865 "synchronization error (input sent without waiting for greeting): "
1866 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1867 string_printing(smtp_inptr));
1868 smtp_printf("554 SMTP synchronization error\r\n");
1872 /* Now output the banner */
1874 smtp_printf("%s", ss);
1882 /*************************************************
1883 * Handle SMTP syntax and protocol errors *
1884 *************************************************/
1886 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1887 to do so. Then transmit the error response. The return value depends on the
1888 number of syntax and protocol errors in this SMTP session.
1891 type error type, given as a log flag bit
1892 code response code; <= 0 means don't send a response
1893 data data to reflect in the response (can be NULL)
1894 errmess the error message
1896 Returns: -1 limit of syntax/protocol errors NOT exceeded
1897 +1 limit of syntax/protocol errors IS exceeded
1899 These values fit in with the values of the "done" variable in the main
1900 processing loop in smtp_setup_msg(). */
1903 synprot_error(int type, int code, uschar *data, uschar *errmess)
1907 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1908 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1909 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1911 if (++synprot_error_count > smtp_max_synprot_errors)
1914 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1915 "syntax or protocol errors (last command was \"%s\")",
1916 host_and_ident(FALSE), smtp_cmd_buffer);
1921 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1922 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1924 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1933 /*************************************************
1934 * Log incomplete transactions *
1935 *************************************************/
1937 /* This function is called after a transaction has been aborted by RSET, QUIT,
1938 connection drops or other errors. It logs the envelope information received
1939 so far in order to preserve address verification attempts.
1941 Argument: string to indicate what aborted the transaction
1946 incomplete_transaction_log(uschar *what)
1948 if (sender_address == NULL || /* No transaction in progress */
1949 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1952 /* Build list of recipients for logging */
1954 if (recipients_count > 0)
1957 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1958 for (i = 0; i < recipients_count; i++)
1959 raw_recipients[i] = recipients_list[i].address;
1960 raw_recipients_count = recipients_count;
1963 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1964 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1970 /*************************************************
1971 * Send SMTP response, possibly multiline *
1972 *************************************************/
1974 /* There are, it seems, broken clients out there that cannot handle multiline
1975 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1976 output nothing for non-final calls, and only the first line for anything else.
1979 code SMTP code, may involve extended status codes
1980 codelen length of smtp code; if > 4 there's an ESC
1981 final FALSE if the last line isn't the final line
1982 msg message text, possibly containing newlines
1988 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
1993 if (!final && no_multiline_responses) return;
1998 esclen = codelen - 4;
2001 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2002 have had the same. Note: this code is also present in smtp_printf(). It would
2003 be tidier to have it only in one place, but when it was added, it was easier to
2004 do it that way, so as not to have to mess with the code for the RCPT command,
2005 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2007 if (rcpt_in_progress)
2009 if (rcpt_smtp_response == NULL)
2010 rcpt_smtp_response = string_copy(msg);
2011 else if (rcpt_smtp_response_same &&
2012 Ustrcmp(rcpt_smtp_response, msg) != 0)
2013 rcpt_smtp_response_same = FALSE;
2014 rcpt_in_progress = FALSE;
2017 /* Not output the message, splitting it up into multiple lines if necessary. */
2021 uschar *nl = Ustrchr(msg, '\n');
2024 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2027 else if (nl[1] == 0 || no_multiline_responses)
2029 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2030 (int)(nl - msg), msg);
2035 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2037 while (isspace(*msg)) msg++;
2045 /*************************************************
2046 * Parse user SMTP message *
2047 *************************************************/
2049 /* This function allows for user messages overriding the response code details
2050 by providing a suitable response code string at the start of the message
2051 user_msg. Check the message for starting with a response code and optionally an
2052 extended status code. If found, check that the first digit is valid, and if so,
2053 change the code pointer and length to use the replacement. An invalid code
2054 causes a panic log; in this case, if the log messages is the same as the user
2055 message, we must also adjust the value of the log message to show the code that
2056 is actually going to be used (the original one).
2058 This function is global because it is called from receive.c as well as within
2061 Note that the code length returned includes the terminating whitespace
2062 character, which is always included in the regex match.
2065 code SMTP code, may involve extended status codes
2066 codelen length of smtp code; if > 4 there's an ESC
2068 log_msg optional log message, to be adjusted with the new SMTP code
2074 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2079 if (msg == NULL || *msg == NULL) return;
2081 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2082 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2085 if ((*msg)[0] != (*code)[0])
2087 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2088 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2089 if (log_msg != NULL && *log_msg == *msg)
2090 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2095 *codelen = ovector[1]; /* Includes final space */
2097 *msg += ovector[1]; /* Chop the code off the message */
2104 /*************************************************
2105 * Handle an ACL failure *
2106 *************************************************/
2108 /* This function is called when acl_check() fails. As well as calls from within
2109 this module, it is called from receive.c for an ACL after DATA. It sorts out
2110 logging the incident, and sets up the error response. A message containing
2111 newlines is turned into a multiline SMTP response, but for logging, only the
2114 There's a table of default permanent failure response codes to use in
2115 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2116 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2117 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2118 state, because there are broken clients that try VRFY before RCPT. A 5xx
2119 response should be given only when the address is positively known to be
2120 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2123 From Exim 4.63, it is possible to override the response code details by
2124 providing a suitable response code string at the start of the message provided
2125 in user_msg. The code's first digit is checked for validity.
2128 where where the ACL was called from
2130 user_msg a message that can be included in an SMTP response
2131 log_msg a message for logging
2133 Returns: 0 in most cases
2134 2 if the failure code was FAIL_DROP, in which case the
2135 SMTP connection should be dropped (this value fits with the
2136 "done" variable in smtp_setup_msg() below)
2140 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2142 BOOL drop = rc == FAIL_DROP;
2146 uschar *sender_info = US"";
2148 #ifdef WITH_CONTENT_SCAN
2149 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2151 (where == ACL_WHERE_PREDATA)? US"DATA" :
2152 (where == ACL_WHERE_DATA)? US"after DATA" :
2153 (smtp_cmd_data == NULL)?
2154 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2155 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2157 if (drop) rc = FAIL;
2159 /* Set the default SMTP code, and allow a user message to change it. */
2161 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2162 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2164 /* We used to have sender_address here; however, there was a bug that was not
2165 updating sender_address after a rewrite during a verify. When this bug was
2166 fixed, sender_address at this point became the rewritten address. I'm not sure
2167 this is what should be logged, so I've changed to logging the unrewritten
2168 address to retain backward compatibility. */
2170 #ifndef WITH_CONTENT_SCAN
2171 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2173 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2176 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
2177 sender_address_unrewritten : sender_address);
2180 /* If there's been a sender verification failure with a specific message, and
2181 we have not sent a response about it yet, do so now, as a preliminary line for
2182 failures, but not defers. However, always log it for defer, and log it for fail
2183 unless the sender_verify_fail log selector has been turned off. */
2185 if (sender_verified_failed != NULL &&
2186 !testflag(sender_verified_failed, af_sverify_told))
2188 BOOL save_rcpt_in_progress = rcpt_in_progress;
2189 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2191 setflag(sender_verified_failed, af_sverify_told);
2193 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2194 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2195 host_and_ident(TRUE),
2196 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2197 sender_verified_failed->address,
2198 (sender_verified_failed->message == NULL)? US"" :
2199 string_sprintf(": %s", sender_verified_failed->message));
2201 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2202 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2203 testflag(sender_verified_failed, af_verify_pmfail)?
2204 "Postmaster verification failed while checking <%s>\n%s\n"
2205 "Several RFCs state that you are required to have a postmaster\n"
2206 "mailbox for each mail domain. This host does not accept mail\n"
2207 "from domains whose servers reject the postmaster address."
2209 testflag(sender_verified_failed, af_verify_nsfail)?
2210 "Callback setup failed while verifying <%s>\n%s\n"
2211 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2212 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2213 "RFC requirements, and stops you from receiving standard bounce\n"
2214 "messages. This host does not accept mail from domains whose servers\n"
2217 "Verification failed for <%s>\n%s",
2218 sender_verified_failed->address,
2219 sender_verified_failed->user_message));
2221 rcpt_in_progress = save_rcpt_in_progress;
2224 /* Sort out text for logging */
2226 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2227 lognl = Ustrchr(log_msg, '\n');
2228 if (lognl != NULL) *lognl = 0;
2230 /* Send permanent failure response to the command, but the code used isn't
2231 always a 5xx one - see comments at the start of this function. If the original
2232 rc was FAIL_DROP we drop the connection and yield 2. */
2234 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2235 US"Administrative prohibition" : user_msg);
2237 /* Send temporary failure response to the command. Don't give any details,
2238 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2239 verb, and for a header verify when smtp_return_error_details is set.
2241 This conditional logic is all somewhat of a mess because of the odd
2242 interactions between temp_details and return_error_details. One day it should
2243 be re-implemented in a tidier fashion. */
2247 if (acl_temp_details && user_msg != NULL)
2249 if (smtp_return_error_details &&
2250 sender_verified_failed != NULL &&
2251 sender_verified_failed->message != NULL)
2253 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2255 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2258 smtp_respond(smtp_code, codelen, TRUE,
2259 US"Temporary local problem - please try later");
2262 /* Log the incident to the logs that are specified by log_reject_target
2263 (default main, reject). This can be empty to suppress logging of rejections. If
2264 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2265 is closing if required and return 2. */
2267 if (log_reject_target != 0)
2268 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2269 host_and_ident(TRUE),
2270 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2272 if (!drop) return 0;
2274 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2275 smtp_get_connection_info());
2277 /* Run the not-quit ACL, but without any custom messages. This should not be a
2278 problem, because we get here only if some other ACL has issued "drop", and
2279 in that case, *its* custom messages will have been used above. */
2281 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2288 /*************************************************
2289 * Handle SMTP exit when QUIT is not given *
2290 *************************************************/
2292 /* This function provides a logging/statistics hook for when an SMTP connection
2293 is dropped on the floor or the other end goes away. It's a global function
2294 because it's called from receive.c as well as this module. As well as running
2295 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2296 response, either with a custom message from the ACL, or using a default. There
2297 is one case, however, when no message is output - after "drop". In that case,
2298 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2299 passed to this function.
2301 In case things go wrong while processing this function, causing an error that
2302 may re-enter this funtion, there is a recursion check.
2305 reason What $smtp_notquit_reason will be set to in the ACL;
2306 if NULL, the ACL is not run
2307 code The error code to return as part of the response
2308 defaultrespond The default message if there's no user_msg
2314 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2317 uschar *user_msg = NULL;
2318 uschar *log_msg = NULL;
2320 /* Check for recursive acll */
2322 if (smtp_exit_function_called)
2324 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2328 smtp_exit_function_called = TRUE;
2330 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2332 if (acl_smtp_notquit != NULL && reason != NULL)
2334 smtp_notquit_reason = reason;
2335 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2338 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2342 /* Write an SMTP response if we are expected to give one. As the default
2343 responses are all internal, they should always fit in the buffer, but code a
2344 warning, just in case. Note that string_vformat() still leaves a complete
2345 string, even if it is incomplete. */
2347 if (code != NULL && defaultrespond != NULL)
2349 if (user_msg == NULL)
2353 va_start(ap, defaultrespond);
2354 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2355 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2356 smtp_printf("%s %s\r\n", code, buffer);
2360 smtp_respond(code, 3, TRUE, user_msg);
2368 /*************************************************
2369 * Verify HELO argument *
2370 *************************************************/
2372 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2373 matched. It is also called from ACL processing if verify = helo is used and
2374 verification was not previously tried (i.e. helo_try_verify_hosts was not
2375 matched). The result of its processing is to set helo_verified and
2376 helo_verify_failed. These variables should both be FALSE for this function to
2379 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2380 for IPv6 ::ffff: literals.
2383 Returns: TRUE if testing was completed;
2384 FALSE on a temporary failure
2388 smtp_verify_helo(void)
2392 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2395 if (sender_helo_name == NULL)
2397 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2400 /* Deal with the case of -bs without an IP address */
2402 else if (sender_host_address == NULL)
2404 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2405 helo_verified = TRUE;
2408 /* Deal with the more common case when there is a sending IP address */
2410 else if (sender_helo_name[0] == '[')
2412 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2413 Ustrlen(sender_host_address)) == 0;
2418 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2419 helo_verified = Ustrncmp(sender_helo_name + 1,
2420 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2425 { if (helo_verified) debug_printf("matched host address\n"); }
2428 /* Do a reverse lookup if one hasn't already given a positive or negative
2429 response. If that fails, or the name doesn't match, try checking with a forward
2434 if (sender_host_name == NULL && !host_lookup_failed)
2435 yield = host_name_lookup() != DEFER;
2437 /* If a host name is known, check it and all its aliases. */
2439 if (sender_host_name != NULL)
2441 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2445 HDEBUG(D_receive) debug_printf("matched host name\n");
2449 uschar **aliases = sender_host_aliases;
2450 while (*aliases != NULL)
2452 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2453 if (helo_verified) break;
2458 debug_printf("matched alias %s\n", *(--aliases));
2463 /* Final attempt: try a forward lookup of the helo name */
2469 h.name = sender_helo_name;
2473 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2475 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2476 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2481 if (Ustrcmp(hh->address, sender_host_address) == 0)
2483 helo_verified = TRUE;
2485 debug_printf("IP address for %s matches calling address\n",
2495 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2502 /*************************************************
2503 * Send user response message *
2504 *************************************************/
2506 /* This function is passed a default response code and a user message. It calls
2507 smtp_message_code() to check and possibly modify the response code, and then
2508 calls smtp_respond() to transmit the response. I put this into a function
2509 just to avoid a lot of repetition.
2512 code the response code
2513 user_msg the user message
2519 smtp_user_msg(uschar *code, uschar *user_msg)
2522 smtp_message_code(&code, &len, &user_msg, NULL);
2523 smtp_respond(code, len, TRUE, user_msg);
2529 /*************************************************
2530 * Initialize for SMTP incoming message *
2531 *************************************************/
2533 /* This function conducts the initial dialogue at the start of an incoming SMTP
2534 message, and builds a list of recipients. However, if the incoming message
2535 is part of a batch (-bS option) a separate function is called since it would
2536 be messy having tests splattered about all over this function. This function
2537 therefore handles the case where interaction is occurring. The input and output
2538 files are set up in smtp_in and smtp_out.
2540 The global recipients_list is set to point to a vector of recipient_item
2541 blocks, whose number is given by recipients_count. This is extended by the
2542 receive_add_recipient() function. The global variable sender_address is set to
2543 the sender's address. The yield is +1 if a message has been successfully
2544 started, 0 if a QUIT command was encountered or the connection was refused from
2545 the particular host, or -1 if the connection was lost.
2549 Returns: > 0 message successfully started (reached DATA)
2550 = 0 QUIT read or end of file reached or call refused
2555 smtp_setup_msg(void)
2558 BOOL toomany = FALSE;
2559 BOOL discarded = FALSE;
2560 BOOL last_was_rej_mail = FALSE;
2561 BOOL last_was_rcpt = FALSE;
2562 void *reset_point = store_get(0);
2564 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2566 /* Reset for start of new message. We allow one RSET not to be counted as a
2567 nonmail command, for those MTAs that insist on sending it between every
2568 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2569 TLS between messages (an Exim client may do this if it has messages queued up
2570 for the host). Note: we do NOT reset AUTH at this point. */
2572 smtp_reset(reset_point);
2573 message_ended = END_NOTSTARTED;
2575 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2576 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2577 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2579 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2582 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2584 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2586 /* Batched SMTP is handled in a different function. */
2588 if (smtp_batched_input) return smtp_setup_batch_msg();
2590 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2591 value. The values are 2 larger than the required yield of the function. */
2596 uschar *etrn_command;
2597 uschar *etrn_serialize_key;
2599 uschar *log_msg, *smtp_code;
2600 uschar *user_msg = NULL;
2601 uschar *recipient = NULL;
2602 uschar *hello = NULL;
2603 uschar *set_id = NULL;
2605 BOOL was_rej_mail = FALSE;
2606 BOOL was_rcpt = FALSE;
2607 void (*oldsignal)(int);
2609 int start, end, sender_domain, recipient_domain;
2614 switch(smtp_read_command(TRUE))
2616 /* The AUTH command is not permitted to occur inside a transaction, and may
2617 occur successfully only once per connection. Actually, that isn't quite
2618 true. When TLS is started, all previous information about a connection must
2619 be discarded, so a new AUTH is permitted at that time.
2621 AUTH may only be used when it has been advertised. However, it seems that
2622 there are clients that send AUTH when it hasn't been advertised, some of
2623 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2624 So there's a get-out that allows this to happen.
2626 AUTH is initially labelled as a "nonmail command" so that one occurrence
2627 doesn't get counted. We change the label here so that multiple failing
2628 AUTHS will eventually hit the nonmail threshold. */
2632 authentication_failed = TRUE;
2633 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2635 if (!auth_advertised && !allow_auth_unadvertised)
2637 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2638 US"AUTH command used when not advertised");
2641 if (sender_host_authenticated != NULL)
2643 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2644 US"already authenticated");
2647 if (sender_address != NULL)
2649 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2650 US"not permitted in mail transaction");
2656 if (acl_smtp_auth != NULL)
2658 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2661 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2666 /* Find the name of the requested authentication mechanism. */
2669 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
2671 if (!isalnum(c) && c != '-' && c != '_')
2673 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2674 US"invalid character in authentication mechanism name");
2680 /* If not at the end of the line, we must be at white space. Terminate the
2681 name and move the pointer on to any data that may be present. */
2683 if (*smtp_cmd_data != 0)
2685 *smtp_cmd_data++ = 0;
2686 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
2689 /* Search for an authentication mechanism which is configured for use
2690 as a server and which has been advertised (unless, sigh, allow_auth_
2691 unadvertised is set). */
2693 for (au = auths; au != NULL; au = au->next)
2695 if (strcmpic(s, au->public_name) == 0 && au->server &&
2696 (au->advertised || allow_auth_unadvertised)) break;
2701 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2702 string_sprintf("%s authentication mechanism not supported", s));
2706 /* Run the checking code, passing the remainder of the command line as
2707 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2708 it as the only set numerical variable. The authenticator may set $auth<n>
2709 and also set other numeric variables. The $auth<n> variables are preferred
2710 nowadays; the numerical variables remain for backwards compatibility.
2712 Afterwards, have a go at expanding the set_id string, even if
2713 authentication failed - for bad passwords it can be useful to log the
2714 userid. On success, require set_id to expand and exist, and put it in
2715 authenticated_id. Save this in permanent store, as the working store gets
2716 reset at HELO, RSET, etc. */
2718 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2720 expand_nlength[0] = 0; /* $0 contains nothing */
2722 c = (au->info->servercode)(au, smtp_cmd_data);
2723 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2724 expand_nmax = -1; /* Reset numeric variables */
2725 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2727 /* The value of authenticated_id is stored in the spool file and printed in
2728 log lines. It must not contain binary zeros or newline characters. In
2729 normal use, it never will, but when playing around or testing, this error
2730 can (did) happen. To guard against this, ensure that the id contains only
2731 printing characters. */
2733 if (set_id != NULL) set_id = string_printing(set_id);
2735 /* For the non-OK cases, set up additional logging data if set_id
2740 if (set_id != NULL && *set_id != 0)
2741 set_id = string_sprintf(" (set_id=%s)", set_id);
2745 /* Switch on the result */
2750 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2752 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2753 sender_host_authenticated = au->name;
2754 authentication_failed = FALSE;
2756 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2757 ((sender_host_address != NULL)? pnlocal : 0);
2758 s = ss = US"235 Authentication succeeded";
2759 authenticated_by = au;
2763 /* Authentication succeeded, but we failed to expand the set_id string.
2764 Treat this as a temporary error. */
2766 auth_defer_msg = expand_string_message;
2770 s = string_sprintf("435 Unable to authenticate at present%s",
2771 auth_defer_user_msg);
2772 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2773 set_id, auth_defer_msg);
2777 s = ss = US"501 Invalid base64 data";
2781 s = ss = US"501 Authentication cancelled";
2785 s = ss = US"553 Initial data not expected";
2789 s = US"535 Incorrect authentication data";
2790 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2794 s = US"435 Internal error";
2795 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2796 "check", set_id, c);
2800 smtp_printf("%s\r\n", s);
2802 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2803 au->name, host_and_ident(FALSE), ss);
2805 break; /* AUTH_CMD */
2807 /* The HELO/EHLO commands are permitted to appear in the middle of a
2808 session as well as at the beginning. They have the effect of a reset in
2809 addition to their other functions. Their absence at the start cannot be
2810 taken to be an error.
2814 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2815 or 502 failure replies MUST be returned as appropriate. The SMTP
2816 server MUST stay in the same state after transmitting these replies
2817 that it was in before the EHLO was received.
2819 Therefore, we do not do the reset until after checking the command for
2820 acceptability. This change was made for Exim release 4.11. Previously
2821 it did the reset first. */
2834 HELO_EHLO: /* Common code for HELO and EHLO */
2835 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2836 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2838 /* Reject the HELO if its argument was invalid or non-existent. A
2839 successful check causes the argument to be saved in malloc store. */
2841 if (!check_helo(smtp_cmd_data))
2843 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2845 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2846 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2847 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2848 string_printing(smtp_cmd_argument));
2850 if (++synprot_error_count > smtp_max_synprot_errors)
2852 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2853 "syntax or protocol errors (last command was \"%s\")",
2854 host_and_ident(FALSE), smtp_cmd_buffer);
2861 /* If sender_host_unknown is true, we have got here via the -bs interface,
2862 not called from inetd. Otherwise, we are running an IP connection and the
2863 host address will be set. If the helo name is the primary name of this
2864 host and we haven't done a reverse lookup, force one now. If helo_required
2865 is set, ensure that the HELO name matches the actual host. If helo_verify
2866 is set, do the same check, but softly. */
2868 if (!sender_host_unknown)
2870 BOOL old_helo_verified = helo_verified;
2871 uschar *p = smtp_cmd_data;
2873 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2876 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2877 because otherwise the log can be confusing. */
2879 if (sender_host_name == NULL &&
2880 (deliver_domain = sender_helo_name, /* set $domain */
2881 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2882 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2883 (void)host_name_lookup();
2885 /* Rebuild the fullhost info to include the HELO name (and the real name
2886 if it was looked up.) */
2888 host_build_sender_fullhost(); /* Rebuild */
2889 set_process_info("handling%s incoming connection from %s",
2890 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2892 /* Verify if configured. This doesn't give much security, but it does
2893 make some people happy to be able to do it. If helo_required is set,
2894 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2895 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2896 now obsolescent, since the verification can now be requested selectively
2899 helo_verified = helo_verify_failed = FALSE;
2900 if (helo_required || helo_verify)
2902 BOOL tempfail = !smtp_verify_helo();
2907 smtp_printf("%d %s argument does not match calling host\r\n",
2908 tempfail? 451 : 550, hello);
2909 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2910 tempfail? "temporarily " : "",
2911 hello, sender_helo_name, host_and_ident(FALSE));
2912 helo_verified = old_helo_verified;
2913 break; /* End of HELO/EHLO processing */
2915 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2916 "helo_try_verify_hosts\n", hello);
2921 #ifdef EXPERIMENTAL_SPF
2922 /* set up SPF context */
2923 spf_init(sender_helo_name, sender_host_address);
2926 /* Apply an ACL check if one is defined; afterwards, recheck
2927 synchronization in case the client started sending in a delay. */
2929 if (acl_smtp_helo != NULL)
2931 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2934 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2935 sender_helo_name = NULL;
2936 host_build_sender_fullhost(); /* Rebuild */
2939 else if (!check_sync()) goto SYNC_FAILURE;
2942 /* Generate an OK reply. The default string includes the ident if present,
2943 and also the IP address if present. Reflecting back the ident is intended
2944 as a deterrent to mail forgers. For maximum efficiency, and also because
2945 some broken systems expect each response to be in a single packet, arrange
2946 that the entire reply is sent in one write(). */
2948 auth_advertised = FALSE;
2949 pipelining_advertised = FALSE;
2951 tls_advertised = FALSE;
2954 smtp_code = US"250 "; /* Default response code plus space*/
2955 if (user_msg == NULL)
2957 s = string_sprintf("%.3s %s Hello %s%s%s",
2959 smtp_active_hostname,
2960 (sender_ident == NULL)? US"" : sender_ident,
2961 (sender_ident == NULL)? US"" : US" at ",
2962 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2967 if (sender_host_address != NULL)
2969 s = string_cat(s, &size, &ptr, US" [", 2);
2970 s = string_cat(s, &size, &ptr, sender_host_address,
2971 Ustrlen(sender_host_address));
2972 s = string_cat(s, &size, &ptr, US"]", 1);
2976 /* A user-supplied EHLO greeting may not contain more than one line. Note
2977 that the code returned by smtp_message_code() includes the terminating
2978 whitespace character. */
2984 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
2985 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
2986 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
2988 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
2989 "newlines: message truncated: %s", string_printing(s));
2996 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2998 /* If we received EHLO, we must create a multiline response which includes
2999 the functions supported. */
3005 /* I'm not entirely happy with this, as an MTA is supposed to check
3006 that it has enough room to accept a message of maximum size before
3007 it sends this. However, there seems little point in not sending it.
3008 The actual size check happens later at MAIL FROM time. By postponing it
3009 till then, VRFY and EXPN can be used after EHLO when space is short. */
3011 if (thismessage_size_limit > 0)
3013 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3014 thismessage_size_limit);
3015 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3019 s = string_cat(s, &size, &ptr, smtp_code, 3);
3020 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3023 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3024 clean; if it has an 8-bit character in its hand, it just sends it. It
3025 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3026 However, some users want this option simply in order to stop MUAs
3027 mangling messages that contain top-bit-set characters. It is therefore
3028 provided as an option. */
3030 if (accept_8bitmime)
3032 s = string_cat(s, &size, &ptr, smtp_code, 3);
3033 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3036 /* Advertise ETRN if there's an ACL checking whether a host is
3037 permitted to issue it; a check is made when any host actually tries. */
3039 if (acl_smtp_etrn != NULL)
3041 s = string_cat(s, &size, &ptr, smtp_code, 3);
3042 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3045 /* Advertise EXPN if there's an ACL checking whether a host is
3046 permitted to issue it; a check is made when any host actually tries. */
3048 if (acl_smtp_expn != NULL)
3050 s = string_cat(s, &size, &ptr, smtp_code, 3);
3051 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3054 /* Exim is quite happy with pipelining, so let the other end know that
3055 it is safe to use it, unless advertising is disabled. */
3057 if (pipelining_enable &&
3058 verify_check_host(&pipelining_advertise_hosts) == OK)
3060 s = string_cat(s, &size, &ptr, smtp_code, 3);
3061 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3062 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3063 pipelining_advertised = TRUE;
3066 /* If any server authentication mechanisms are configured, advertise
3067 them if the current host is in auth_advertise_hosts. The problem with
3068 advertising always is that some clients then require users to
3069 authenticate (and aren't configurable otherwise) even though it may not
3070 be necessary (e.g. if the host is in host_accept_relay).
3072 RFC 2222 states that SASL mechanism names contain only upper case
3073 letters, so output the names in upper case, though we actually recognize
3074 them in either case in the AUTH command. */
3078 if (verify_check_host(&auth_advertise_hosts) == OK)
3082 for (au = auths; au != NULL; au = au->next)
3084 if (au->server && (au->advertise_condition == NULL ||
3085 expand_check_condition(au->advertise_condition, au->name,
3086 US"authenticator")))
3091 s = string_cat(s, &size, &ptr, smtp_code, 3);
3092 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3094 auth_advertised = TRUE;
3097 s = string_cat(s, &size, &ptr, US" ", 1);
3098 s = string_cat(s, &size, &ptr, au->public_name,
3099 Ustrlen(au->public_name));
3100 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3101 au->advertised = TRUE;
3103 else au->advertised = FALSE;
3105 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3109 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3110 if it has been included in the binary, and the host matches
3111 tls_advertise_hosts. We must *not* advertise if we are already in a
3112 secure connection. */
3115 if (tls_active < 0 &&
3116 verify_check_host(&tls_advertise_hosts) != FAIL)
3118 s = string_cat(s, &size, &ptr, smtp_code, 3);
3119 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3120 tls_advertised = TRUE;
3124 /* Finish off the multiline reply with one that is always available. */
3126 s = string_cat(s, &size, &ptr, smtp_code, 3);
3127 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3130 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3136 if (tls_active >= 0) (void)tls_write(s, ptr); else
3139 (void)fwrite(s, 1, ptr, smtp_out);
3143 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3144 memmove(cr, cr + 1, (ptr--) - (cr - s));
3145 debug_printf("SMTP>> %s", s);
3149 /* Reset the protocol and the state, abandoning any previous message. */
3151 received_protocol = (esmtp?
3153 ((sender_host_authenticated != NULL)? pauthed : 0) +
3154 ((tls_active >= 0)? pcrpted : 0)]
3156 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
3158 ((sender_host_address != NULL)? pnlocal : 0);
3160 smtp_reset(reset_point);
3162 break; /* HELO/EHLO */
3165 /* The MAIL command requires an address as an operand. All we do
3166 here is to parse it for syntactic correctness. The form "<>" is
3167 a special case which converts into an empty string. The start/end
3168 pointers in the original are not used further for this address, as
3169 it is the canonical extracted address which is all that is kept. */
3173 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3174 was_rej_mail = TRUE; /* Reset if accepted */
3176 if (helo_required && !helo_seen)
3178 smtp_printf("503 HELO or EHLO required\r\n");
3179 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3180 "HELO/EHLO given", host_and_ident(FALSE));
3184 if (sender_address != NULL)
3186 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3187 US"sender already given");
3191 if (smtp_cmd_data[0] == 0)
3193 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3194 US"MAIL must have an address operand");
3198 /* Check to see if the limit for messages per connection would be
3199 exceeded by accepting further messages. */
3201 if (smtp_accept_max_per_connection > 0 &&
3202 smtp_mailcmd_count > smtp_accept_max_per_connection)
3204 smtp_printf("421 too many messages in this connection\r\n");
3205 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3206 "messages in one connection", host_and_ident(TRUE));
3210 /* Reset for start of message - even if this is going to fail, we
3211 obviously need to throw away any previous data. */
3213 smtp_reset(reset_point);
3215 sender_data = recipient_data = NULL;
3217 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3221 uschar *name, *value, *end;
3222 unsigned long int size;
3224 if (!extract_option(&name, &value)) break;
3226 /* Handle SIZE= by reading the value. We don't do the check till later,
3227 in order to be able to log the sender address on failure. */
3229 if (strcmpic(name, US"SIZE") == 0 &&
3230 ((size = Ustrtoul(value, &end, 10)), *end == 0))
3232 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3234 message_size = (int)size;
3237 /* If this session was initiated with EHLO and accept_8bitmime is set,
3238 Exim will have indicated that it supports the BODY=8BITMIME option. In
3239 fact, it does not support this according to the RFCs, in that it does not
3240 take any special action for forwarding messages containing 8-bit
3241 characters. That is why accept_8bitmime is not the default setting, but
3242 some sites want the action that is provided. We recognize both "8BITMIME"
3243 and "7BIT" as body types, but take no action. */
3245 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
3246 (strcmpic(value, US"8BITMIME") == 0 ||
3247 strcmpic(value, US"7BIT") == 0)) {}
3249 /* Handle the AUTH extension. If the value given is not "<>" and either
3250 the ACL says "yes" or there is no ACL but the sending host is
3251 authenticated, we set it up as the authenticated sender. However, if the
3252 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3253 the condition is met. The value of AUTH is an xtext, which means that +,
3254 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3257 else if (strcmpic(name, US"AUTH") == 0)
3259 if (Ustrcmp(value, "<>") != 0)
3264 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3266 /* Put back terminator overrides for error message */
3269 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3270 US"invalid data for AUTH");
3274 if (acl_smtp_mailauth == NULL)
3276 ignore_msg = US"client not authenticated";
3277 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3281 ignore_msg = US"rejected by ACL";
3282 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3283 &user_msg, &log_msg);
3289 if (authenticated_by == NULL ||
3290 authenticated_by->mail_auth_condition == NULL ||
3291 expand_check_condition(authenticated_by->mail_auth_condition,
3292 authenticated_by->name, US"authenticator"))
3293 break; /* Accept the AUTH */
3295 ignore_msg = US"server_mail_auth_condition failed";
3296 if (authenticated_id != NULL)
3297 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3298 ignore_msg, authenticated_id);
3303 authenticated_sender = NULL;
3304 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3305 value, host_and_ident(TRUE), ignore_msg);
3308 /* Should only get DEFER or ERROR here. Put back terminator
3309 overrides for error message */
3314 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3321 /* Unknown option. Stick back the terminator characters and break
3322 the loop. An error for a malformed address will occur. */
3332 /* If we have passed the threshold for rate limiting, apply the current
3333 delay, and update it for next time, provided this is a limited host. */
3335 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3336 verify_check_host(&smtp_ratelimit_hosts) == OK)
3338 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3339 smtp_delay_mail/1000.0);
3340 millisleep((int)smtp_delay_mail);
3341 smtp_delay_mail *= smtp_rlm_factor;
3342 if (smtp_delay_mail > (double)smtp_rlm_limit)
3343 smtp_delay_mail = (double)smtp_rlm_limit;
3346 /* Now extract the address, first applying any SMTP-time rewriting. The
3347 TRUE flag allows "<>" as a sender address. */
3349 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3350 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3351 global_rewrite_rules) : smtp_cmd_data;
3353 /* rfc821_domains = TRUE; << no longer needed */
3355 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3357 /* rfc821_domains = FALSE; << no longer needed */
3359 if (raw_sender == NULL)
3361 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3365 sender_address = raw_sender;
3367 /* If there is a configured size limit for mail, check that this message
3368 doesn't exceed it. The check is postponed to this point so that the sender
3371 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3373 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3374 log_write(L_size_reject,
3375 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3376 "message too big: size%s=%d max=%d",
3378 host_and_ident(TRUE),
3379 (message_size == INT_MAX)? ">" : "",
3381 thismessage_size_limit);
3382 sender_address = NULL;
3386 /* Check there is enough space on the disk unless configured not to.
3387 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3388 plus the current message - i.e. we accept the message only if it won't
3389 reduce the space below the threshold. Add 5000 to the size to allow for
3390 overheads such as the Received: line and storing of recipients, etc.
3391 By putting the check here, even when SIZE is not given, it allow VRFY
3392 and EXPN etc. to be used when space is short. */
3394 if (!receive_check_fs(
3395 (smtp_check_spool_space && message_size >= 0)?
3396 message_size + 5000 : 0))
3398 smtp_printf("452 Space shortage, please try later\r\n");
3399 sender_address = NULL;
3403 /* If sender_address is unqualified, reject it, unless this is a locally
3404 generated message, or the sending host or net is permitted to send
3405 unqualified addresses - typically local machines behaving as MUAs -
3406 in which case just qualify the address. The flag is set above at the start
3407 of the SMTP connection. */
3409 if (sender_domain == 0 && sender_address[0] != 0)
3411 if (allow_unqualified_sender)
3413 sender_domain = Ustrlen(sender_address) + 1;
3414 sender_address = rewrite_address_qualify(sender_address, FALSE);
3415 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3420 smtp_printf("501 %s: sender address must contain a domain\r\n",
3422 log_write(L_smtp_syntax_error,
3423 LOG_MAIN|LOG_REJECT,
3424 "unqualified sender rejected: <%s> %s%s",
3426 host_and_ident(TRUE),
3428 sender_address = NULL;
3433 /* Apply an ACL check if one is defined, before responding. Afterwards,
3434 when pipelining is not advertised, do another sync check in case the ACL
3435 delayed and the client started sending in the meantime. */
3437 if (acl_smtp_mail == NULL) rc = OK; else
3439 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3440 if (rc == OK && !pipelining_advertised && !check_sync())
3444 if (rc == OK || rc == DISCARD)
3446 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3447 else smtp_user_msg(US"250", user_msg);
3448 smtp_delay_rcpt = smtp_rlr_base;
3449 recipients_discarded = (rc == DISCARD);
3450 was_rej_mail = FALSE;
3454 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3455 sender_address = NULL;
3460 /* The RCPT command requires an address as an operand. There may be any
3461 number of RCPT commands, specifying multiple recipients. We build them all
3462 into a data structure. The start/end values given by parse_extract_address
3463 are not used, as we keep only the extracted address. */
3468 was_rcpt = rcpt_in_progress = TRUE;
3470 /* There must be a sender address; if the sender was rejected and
3471 pipelining was advertised, we assume the client was pipelining, and do not
3472 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3473 get the same treatment. */
3475 if (sender_address == NULL)
3477 if (pipelining_advertised && last_was_rej_mail)
3479 smtp_printf("503 sender not yet given\r\n");
3480 was_rej_mail = TRUE;
3484 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3485 US"sender not yet given");
3486 was_rcpt = FALSE; /* Not a valid RCPT */
3492 /* Check for an operand */
3494 if (smtp_cmd_data[0] == 0)
3496 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3497 US"RCPT must have an address operand");
3502 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3503 as a recipient address */
3505 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3506 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3507 global_rewrite_rules) : smtp_cmd_data;
3509 /* rfc821_domains = TRUE; << no longer needed */
3510 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3511 &recipient_domain, FALSE);
3512 /* rfc821_domains = FALSE; << no longer needed */
3514 if (recipient == NULL)
3516 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3521 /* If the recipient address is unqualified, reject it, unless this is a
3522 locally generated message. However, unqualified addresses are permitted
3523 from a configured list of hosts and nets - typically when behaving as
3524 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3525 really. The flag is set at the start of the SMTP connection.
3527 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3528 assumed this meant "reserved local part", but the revision of RFC 821 and
3529 friends now makes it absolutely clear that it means *mailbox*. Consequently
3530 we must always qualify this address, regardless. */
3532 if (recipient_domain == 0)
3534 if (allow_unqualified_recipient ||
3535 strcmpic(recipient, US"postmaster") == 0)
3537 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3539 recipient_domain = Ustrlen(recipient) + 1;
3540 recipient = rewrite_address_qualify(recipient, TRUE);
3545 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3547 log_write(L_smtp_syntax_error,
3548 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3549 "<%s> %s%s", recipient, host_and_ident(TRUE),
3555 /* Check maximum allowed */
3557 if (rcpt_count > recipients_max && recipients_max > 0)
3559 if (recipients_max_reject)
3562 smtp_printf("552 too many recipients\r\n");
3564 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3565 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3570 smtp_printf("452 too many recipients\r\n");
3572 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3573 "temporarily rejected: sender=<%s> %s", sender_address,
3574 host_and_ident(TRUE));
3581 /* If we have passed the threshold for rate limiting, apply the current
3582 delay, and update it for next time, provided this is a limited host. */
3584 if (rcpt_count > smtp_rlr_threshold &&
3585 verify_check_host(&smtp_ratelimit_hosts) == OK)
3587 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3588 smtp_delay_rcpt/1000.0);
3589 millisleep((int)smtp_delay_rcpt);
3590 smtp_delay_rcpt *= smtp_rlr_factor;
3591 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3592 smtp_delay_rcpt = (double)smtp_rlr_limit;
3595 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3596 for them. Otherwise, check the access control list for this recipient. As
3597 there may be a delay in this, re-check for a synchronization error
3598 afterwards, unless pipelining was advertised. */
3600 if (recipients_discarded) rc = DISCARD; else
3602 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
3604 if (rc == OK && !pipelining_advertised && !check_sync())
3608 /* The ACL was happy */
3612 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3613 else smtp_user_msg(US"250", user_msg);
3614 receive_add_recipient(recipient, -1);
3617 /* The recipient was discarded */
3619 else if (rc == DISCARD)
3621 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3622 else smtp_user_msg(US"250", user_msg);
3625 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3626 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3627 (sender_address_unrewritten != NULL)?
3628 sender_address_unrewritten : sender_address,
3629 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3630 (log_msg == NULL)? US"" : US": ",
3631 (log_msg == NULL)? US"" : log_msg);
3634 /* Either the ACL failed the address, or it was deferred. */
3638 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3639 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3644 /* The DATA command is legal only if it follows successful MAIL FROM
3645 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3646 not counted as a protocol error if it follows RCPT (which must have been
3647 rejected if there are no recipients.) This function is complete when a
3648 valid DATA command is encountered.
3650 Note concerning the code used: RFC 2821 says this:
3652 - If there was no MAIL, or no RCPT, command, or all such commands
3653 were rejected, the server MAY return a "command out of sequence"
3654 (503) or "no valid recipients" (554) reply in response to the
3657 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3658 because it is the same whether pipelining is in use or not.
3660 If all the RCPT commands that precede DATA provoked the same error message
3661 (often indicating some kind of system error), it is helpful to include it
3662 with the DATA rejection (an idea suggested by Tony Finch). */
3666 if (!discarded && recipients_count <= 0)
3668 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
3670 uschar *code = US"503";
3671 int len = Ustrlen(rcpt_smtp_response);
3672 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
3674 /* Responses from smtp_printf() will have \r\n on the end */
3675 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
3676 rcpt_smtp_response[len-2] = 0;
3677 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
3679 if (pipelining_advertised && last_was_rcpt)
3680 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
3682 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3683 US"valid RCPT command must precede DATA");
3687 if (toomany && recipients_max_reject)
3689 sender_address = NULL; /* This will allow a new MAIL without RSET */
3690 sender_address_unrewritten = NULL;
3691 smtp_printf("554 Too many recipients\r\n");
3695 /* If there is an ACL, re-check the synchronization afterwards, since the
3696 ACL may have delayed. */
3698 if (acl_smtp_predata == NULL) rc = OK; else
3700 enable_dollar_recipients = TRUE;
3701 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3703 enable_dollar_recipients = FALSE;
3704 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
3709 if (user_msg == NULL)
3710 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3711 else smtp_user_msg(US"354", user_msg);
3713 message_ended = END_NOTENDED; /* Indicate in middle of data */
3716 /* Either the ACL failed the address, or it was deferred. */
3719 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3725 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3727 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3733 /* rfc821_domains = TRUE; << no longer needed */
3734 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
3735 &recipient_domain, FALSE);
3736 /* rfc821_domains = FALSE; << no longer needed */
3738 if (address == NULL)
3739 s = string_sprintf("501 %s", errmess);
3742 address_item *addr = deliver_make_addr(address, FALSE);
3743 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3744 -1, -1, NULL, NULL, NULL))
3747 s = string_sprintf("250 <%s> is deliverable", address);
3751 s = (addr->user_message != NULL)?
3752 string_sprintf("451 <%s> %s", address, addr->user_message) :
3753 string_sprintf("451 Cannot resolve <%s> at this time", address);
3757 s = (addr->user_message != NULL)?
3758 string_sprintf("550 <%s> %s", address, addr->user_message) :
3759 string_sprintf("550 <%s> is not deliverable", address);
3760 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3761 smtp_cmd_argument, host_and_ident(TRUE));
3766 smtp_printf("%s\r\n", s);
3773 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3775 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3778 BOOL save_log_testing_mode = log_testing_mode;
3779 address_test_mode = log_testing_mode = TRUE;
3780 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
3781 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3783 address_test_mode = FALSE;
3784 log_testing_mode = save_log_testing_mode; /* true for -bh */
3793 if (!tls_advertised)
3795 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3796 US"STARTTLS command used when not advertised");
3800 /* Apply an ACL check if one is defined */
3802 if (acl_smtp_starttls != NULL)
3804 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3808 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3813 /* RFC 2487 is not clear on when this command may be sent, though it
3814 does state that all information previously obtained from the client
3815 must be discarded if a TLS session is started. It seems reasonble to
3816 do an implied RSET when STARTTLS is received. */
3818 incomplete_transaction_log(US"STARTTLS");
3819 smtp_reset(reset_point);
3821 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3823 /* Attempt to start up a TLS session, and if successful, discard all
3824 knowledge that was obtained previously. At least, that's what the RFC says,
3825 and that's what happens by default. However, in order to work round YAEB,
3826 there is an option to remember the esmtp state. Sigh.
3828 We must allow for an extra EHLO command and an extra AUTH command after
3829 STARTTLS that don't add to the nonmail command count. */
3831 if ((rc = tls_server_start(tls_require_ciphers, gnutls_require_mac,
3832 gnutls_require_kx, gnutls_require_proto)) == OK)
3834 if (!tls_remember_esmtp)
3835 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3836 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3837 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3838 if (sender_helo_name != NULL)
3840 store_free(sender_helo_name);
3841 sender_helo_name = NULL;
3842 host_build_sender_fullhost(); /* Rebuild */
3843 set_process_info("handling incoming TLS connection from %s",
3844 host_and_ident(FALSE));
3846 received_protocol = (esmtp?
3847 protocols[pextend + pcrpted +
3848 ((sender_host_authenticated != NULL)? pauthed : 0)]
3850 protocols[pnormal + pcrpted])
3852 ((sender_host_address != NULL)? pnlocal : 0);
3854 sender_host_authenticated = NULL;
3855 authenticated_id = NULL;
3856 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3857 DEBUG(D_tls) debug_printf("TLS active\n");
3858 break; /* Successful STARTTLS */
3861 /* Some local configuration problem was discovered before actually trying
3862 to do a TLS handshake; give a temporary error. */
3864 else if (rc == DEFER)
3866 smtp_printf("454 TLS currently unavailable\r\n");
3870 /* Hard failure. Reject everything except QUIT or closed connection. One
3871 cause for failure is a nested STARTTLS, in which case tls_active remains
3872 set, but we must still reject all incoming commands. */
3874 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3877 switch(smtp_read_command(FALSE))
3880 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3881 smtp_get_connection_info());
3882 smtp_notquit_exit(US"tls-failed", NULL, NULL);
3886 /* It is perhaps arguable as to which exit ACL should be called here,
3887 but as it is probably a situtation that almost never arises, it
3888 probably doesn't matter. We choose to call the real QUIT ACL, which in
3889 some sense is perhaps "right". */
3893 if (acl_smtp_quit != NULL)
3895 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
3898 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3901 if (user_msg == NULL)
3902 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3904 smtp_respond(US"221", 3, TRUE, user_msg);
3905 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3906 smtp_get_connection_info());
3911 smtp_printf("554 Security failure\r\n");
3920 /* The ACL for QUIT is provided for gathering statistical information or
3921 similar; it does not affect the response code, but it can supply a custom
3926 incomplete_transaction_log(US"QUIT");
3927 if (acl_smtp_quit != NULL)
3929 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
3931 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3934 if (user_msg == NULL)
3935 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3937 smtp_respond(US"221", 3, TRUE, user_msg);
3944 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3945 smtp_get_connection_info());
3951 incomplete_transaction_log(US"RSET");
3952 smtp_reset(reset_point);
3954 smtp_printf("250 Reset OK\r\n");
3955 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3961 smtp_printf("250 OK\r\n");
3965 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
3966 used, a check will be done for permitted hosts. Show STARTTLS only if not
3967 already in a TLS session and if it would be advertised in the EHLO
3972 smtp_printf("214-Commands supported:\r\n");
3976 Ustrcat(buffer, " AUTH");
3978 if (tls_active < 0 &&
3979 verify_check_host(&tls_advertise_hosts) != FAIL)
3980 Ustrcat(buffer, " STARTTLS");
3982 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3983 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3984 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3985 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3986 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3987 smtp_printf("214%s\r\n", buffer);
3993 incomplete_transaction_log(US"connection lost");
3994 smtp_notquit_exit(US"connection-lost", US"421",
3995 US"%s lost input connection", smtp_active_hostname);
3997 /* Don't log by default unless in the middle of a message, as some mailers
3998 just drop the call rather than sending QUIT, and it clutters up the logs.
4001 if (sender_address != NULL || recipients_count > 0)
4002 log_write(L_lost_incoming_connection,
4004 "unexpected %s while reading SMTP command from %s%s",
4005 sender_host_unknown? "EOF" : "disconnection",
4006 host_and_ident(FALSE), smtp_read_error);
4008 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4009 smtp_get_connection_info(), smtp_read_error);
4017 if (sender_address != NULL)
4019 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4020 US"ETRN is not permitted inside a transaction");
4024 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4025 host_and_ident(FALSE));
4027 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4030 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4034 /* Compute the serialization key for this command. */
4036 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4038 /* If a command has been specified for running as a result of ETRN, we
4039 permit any argument to ETRN. If not, only the # standard form is permitted,
4040 since that is strictly the only kind of ETRN that can be implemented
4041 according to the RFC. */
4043 if (smtp_etrn_command != NULL)
4047 etrn_command = smtp_etrn_command;
4048 deliver_domain = smtp_cmd_data;
4049 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4050 US"ETRN processing", &error);
4051 deliver_domain = NULL;
4054 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4056 smtp_printf("458 Internal failure\r\n");
4061 /* Else set up to call Exim with the -R option. */
4065 if (*smtp_cmd_data++ != '#')
4067 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4068 US"argument must begin with #");
4071 etrn_command = US"exim -R";
4072 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4076 /* If we are host-testing, don't actually do anything. */
4082 debug_printf("ETRN command is: %s\n", etrn_command);
4083 debug_printf("ETRN command execution skipped\n");
4085 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4086 else smtp_user_msg(US"250", user_msg);
4091 /* If ETRN queue runs are to be serialized, check the database to
4092 ensure one isn't already running. */
4094 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4096 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4100 /* Fork a child process and run the command. We don't want to have to
4101 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4102 forking. It should be set that way anyway for external incoming SMTP,
4103 but we save and restore to be tidy. If serialization is required, we
4104 actually run the command in yet another process, so we can wait for it
4105 to complete and then remove the serialization lock. */
4107 oldsignal = signal(SIGCHLD, SIG_IGN);
4109 if ((pid = fork()) == 0)
4111 smtp_input = FALSE; /* This process is not associated with the */
4112 (void)fclose(smtp_in); /* SMTP call any more. */
4113 (void)fclose(smtp_out);
4115 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
4117 /* If not serializing, do the exec right away. Otherwise, fork down
4118 into another process. */
4120 if (!smtp_etrn_serialize || (pid = fork()) == 0)
4122 DEBUG(D_exec) debug_print_argv(argv);
4123 exim_nullstd(); /* Ensure std{in,out,err} exist */
4124 execv(CS argv[0], (char *const *)argv);
4125 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
4126 etrn_command, strerror(errno));
4127 _exit(EXIT_FAILURE); /* paranoia */
4130 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4131 is, we are in the first subprocess, after forking again. All we can do
4132 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4133 complete, before removing the serialization. */
4136 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4137 "failed: %s", strerror(errno));
4141 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4143 (void)wait(&status);
4144 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4148 enq_end(etrn_serialize_key);
4149 _exit(EXIT_SUCCESS);
4152 /* Back in the top level SMTP process. Check that we started a subprocess
4153 and restore the signal state. */
4157 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4159 smtp_printf("458 Unable to fork process\r\n");
4160 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4164 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4165 else smtp_user_msg(US"250", user_msg);
4168 signal(SIGCHLD, oldsignal);
4173 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4174 US"unexpected argument data");
4178 /* This currently happens only for NULLs, but could be extended. */
4181 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
4182 US"NULL character(s) present (shown as '?')");
4183 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
4189 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
4190 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
4191 c = smtp_inend - smtp_inptr;
4192 if (c > 150) c = 150;
4194 incomplete_transaction_log(US"sync failure");
4195 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
4196 "(next input sent too soon: pipelining was%s advertised): "
4197 "rejected \"%s\" %s next input=\"%s\"",
4198 pipelining_advertised? "" : " not",
4199 smtp_cmd_buffer, host_and_ident(TRUE),
4200 string_printing(smtp_inptr));
4201 smtp_notquit_exit(US"synchronization-error", US"554",
4202 US"SMTP synchronization error");
4203 done = 1; /* Pretend eof - drops connection */
4207 case TOO_MANY_NONMAIL_CMD:
4208 s = smtp_cmd_buffer;
4209 while (*s != 0 && !isspace(*s)) s++;
4210 incomplete_transaction_log(US"too many non-mail commands");
4211 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4212 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
4213 s - smtp_cmd_buffer, smtp_cmd_buffer);
4214 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
4215 done = 1; /* Pretend eof - drops connection */
4220 if (unknown_command_count++ >= smtp_max_unknown_commands)
4222 log_write(L_smtp_syntax_error, LOG_MAIN,
4223 "SMTP syntax error in \"%s\" %s %s",
4224 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
4225 US"unrecognized command");
4226 incomplete_transaction_log(US"unrecognized command");
4227 smtp_notquit_exit(US"bad-commands", US"500",
4228 US"Too many unrecognized commands");
4230 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4231 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
4235 done = synprot_error(L_smtp_syntax_error, 500, NULL,
4236 US"unrecognized command");
4240 /* This label is used by goto's inside loops that want to break out to
4241 the end of the command-processing loop. */
4244 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
4245 last_was_rcpt = was_rcpt; /* protocol error handling */
4249 return done - 2; /* Convert yield values */
4252 /* End of smtp_in.c */