1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.63 2008/09/29 11:41:07 nm4 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, ...)
379 va_start(ap, format);
380 smtp_vprintf(format, ap);
384 /* This is split off so that verify.c:respond_printf() can, in effect, call
385 smtp_printf(), bearing in mind that in C a vararg function can't directly
386 call another vararg function, only a function which accepts a va_list.
388 Note also that repeated calls to va_start()/va_end() pairs is claimed to be
389 non-portable; meanwhile, va_copy() is also non-portable in that it's C99, so
390 we end up needing OS support to define it for us. */
393 smtp_vprintf(char *format, va_list ap)
401 (void) string_vformat(big_buffer, big_buffer_size, format, ap_d);
402 end = big_buffer + Ustrlen(big_buffer);
403 while ((cr = Ustrchr(big_buffer, '\r')) != NULL) /* lose CRs */
404 memmove(cr, cr + 1, (end--) - cr);
405 debug_printf("SMTP>> %s", big_buffer);
408 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
410 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
411 smtp_closedown(US"Unexpected error");
412 exim_exit(EXIT_FAILURE);
415 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
416 have had the same. Note: this code is also present in smtp_respond(). It would
417 be tidier to have it only in one place, but when it was added, it was easier to
418 do it that way, so as not to have to mess with the code for the RCPT command,
419 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
421 if (rcpt_in_progress)
423 if (rcpt_smtp_response == NULL)
424 rcpt_smtp_response = string_copy(big_buffer);
425 else if (rcpt_smtp_response_same &&
426 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
427 rcpt_smtp_response_same = FALSE;
428 rcpt_in_progress = FALSE;
431 /* Now write the string */
436 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
441 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
446 /*************************************************
447 * Flush SMTP out and check for error *
448 *************************************************/
450 /* This function isn't currently used within Exim (it detects errors when it
451 tries to read the next SMTP input), but is available for use in local_scan().
452 For non-TLS connections, it flushes the output and checks for errors. For
453 TLS-connections, it checks for a previously-detected TLS write error.
456 Returns: 0 for no error; -1 after an error
462 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
463 return smtp_write_error;
468 /*************************************************
469 * SMTP command read timeout *
470 *************************************************/
472 /* Signal handler for timing out incoming SMTP commands. This attempts to
475 Argument: signal number (SIGALRM)
480 command_timeout_handler(int sig)
482 sig = sig; /* Keep picky compilers happy */
483 log_write(L_lost_incoming_connection,
484 LOG_MAIN, "SMTP command timeout on%s connection from %s",
485 (tls_active >= 0)? " TLS" : "",
486 host_and_ident(FALSE));
487 if (smtp_batched_input)
488 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
489 smtp_notquit_exit(US"command-timeout", US"421",
490 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
491 exim_exit(EXIT_FAILURE);
496 /*************************************************
498 *************************************************/
500 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
502 Argument: signal number (SIGTERM)
507 command_sigterm_handler(int sig)
509 sig = sig; /* Keep picky compilers happy */
510 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
511 if (smtp_batched_input)
512 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
513 smtp_notquit_exit(US"signal-exit", US"421",
514 US"%s: Service not available - closing connection", smtp_active_hostname);
515 exim_exit(EXIT_FAILURE);
521 /*************************************************
522 * Read one command line *
523 *************************************************/
525 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
526 There are sites that don't do this, and in any case internal SMTP probably
527 should check only for LF. Consequently, we check here for LF only. The line
528 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
529 an unknown command. The command is read into the global smtp_cmd_buffer so that
530 it is available via $smtp_command.
532 The character reading routine sets up a timeout for each block actually read
533 from the input (which may contain more than one command). We set up a special
534 signal handler that closes down the session on a timeout. Control does not
538 check_sync if TRUE, check synchronization rules if global option is TRUE
540 Returns: a code identifying the command (enumerated above)
544 smtp_read_command(BOOL check_sync)
549 BOOL hadnull = FALSE;
551 os_non_restarting_signal(SIGALRM, command_timeout_handler);
553 while ((c = (receive_getc)()) != '\n' && c != EOF)
555 if (ptr >= smtp_cmd_buffer_size)
557 os_non_restarting_signal(SIGALRM, sigalrm_handler);
565 smtp_cmd_buffer[ptr++] = c;
568 receive_linecount++; /* For BSMTP errors */
569 os_non_restarting_signal(SIGALRM, sigalrm_handler);
571 /* If hit end of file, return pseudo EOF command. Whether we have a
572 part-line already read doesn't matter, since this is an error state. */
574 if (c == EOF) return EOF_CMD;
576 /* Remove any CR and white space at the end of the line, and terminate the
579 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
580 smtp_cmd_buffer[ptr] = 0;
582 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
584 /* NULLs are not allowed in SMTP commands */
586 if (hadnull) return BADCHAR_CMD;
588 /* Scan command list and return identity, having set the data pointer
589 to the start of the actual data characters. Check for SMTP synchronization
592 for (p = cmd_list; p < cmd_list_end; p++)
594 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
595 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
596 smtp_cmd_buffer[p->len] == 0 ||
597 smtp_cmd_buffer[p->len] == ' '))
599 if (smtp_inptr < smtp_inend && /* Outstanding input */
600 p->cmd < sync_cmd_limit && /* Command should sync */
601 check_sync && /* Local flag set */
602 smtp_enforce_sync && /* Global flag set */
603 sender_host_address != NULL && /* Not local input */
604 !sender_host_notsocket) /* Really is a socket */
607 /* The variables $smtp_command and $smtp_command_argument point into the
608 unmodified input buffer. A copy of the latter is taken for actual
609 processing, so that it can be chopped up into separate parts if necessary,
610 for example, when processing a MAIL command options such as SIZE that can
611 follow the sender address. */
613 smtp_cmd_argument = smtp_cmd_buffer + p->len;
614 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
615 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
616 smtp_cmd_data = smtp_data_buffer;
618 /* Count non-mail commands from those hosts that are controlled in this
619 way. The default is all hosts. We don't waste effort checking the list
620 until we get a non-mail command, but then cache the result to save checking
621 again. If there's a DEFER while checking the host, assume it's in the list.
623 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
624 start of each incoming message by fiddling with the value in the table. */
628 if (count_nonmail == TRUE_UNSET) count_nonmail =
629 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
630 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
631 return TOO_MANY_NONMAIL_CMD;
634 /* If there is data for a command that does not expect it, generate the
637 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
641 /* Enforce synchronization for unknown commands */
643 if (smtp_inptr < smtp_inend && /* Outstanding input */
644 check_sync && /* Local flag set */
645 smtp_enforce_sync && /* Global flag set */
646 sender_host_address != NULL && /* Not local input */
647 !sender_host_notsocket) /* Really is a socket */
655 /*************************************************
656 * Recheck synchronization *
657 *************************************************/
659 /* Synchronization checks can never be perfect because a packet may be on its
660 way but not arrived when the check is done. Such checks can in any case only be
661 done when TLS is not in use. Normally, the checks happen when commands are
662 read: Exim ensures that there is no more input in the input buffer. In normal
663 cases, the response to the command will be fast, and there is no further check.
665 However, for some commands an ACL is run, and that can include delays. In those
666 cases, it is useful to do another check on the input just before sending the
667 response. This also applies at the start of a connection. This function does
668 that check by means of the select() function, as long as the facility is not
669 disabled or inappropriate. A failure of select() is ignored.
671 When there is unwanted input, we read it so that it appears in the log of the
675 Returns: TRUE if all is well; FALSE if there is input pending
683 struct timeval tzero;
685 if (!smtp_enforce_sync || sender_host_address == NULL ||
686 sender_host_notsocket || tls_active >= 0)
689 fd = fileno(smtp_in);
694 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
696 if (rc <= 0) return TRUE; /* Not ready to read */
698 if (rc < 0) return TRUE; /* End of file or error */
701 rc = smtp_inend - smtp_inptr;
702 if (rc > 150) rc = 150;
709 /*************************************************
710 * Forced closedown of call *
711 *************************************************/
713 /* This function is called from log.c when Exim is dying because of a serious
714 disaster, and also from some other places. If an incoming non-batched SMTP
715 channel is open, it swallows the rest of the incoming message if in the DATA
716 phase, sends the reply string, and gives an error to all subsequent commands
717 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
721 message SMTP reply string to send, excluding the code
727 smtp_closedown(uschar *message)
729 if (smtp_in == NULL || smtp_batched_input) return;
730 receive_swallow_smtp();
731 smtp_printf("421 %s\r\n", message);
735 switch(smtp_read_command(FALSE))
741 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
746 smtp_printf("250 Reset OK\r\n");
750 smtp_printf("421 %s\r\n", message);
759 /*************************************************
760 * Set up connection info for logging *
761 *************************************************/
763 /* This function is called when logging information about an SMTP connection.
764 It sets up appropriate source information, depending on the type of connection.
765 If sender_fullhost is NULL, we are at a very early stage of the connection;
766 just use the IP address.
769 Returns: a string describing the connection
773 smtp_get_connection_info(void)
775 uschar *hostname = (sender_fullhost == NULL)?
776 sender_host_address : sender_fullhost;
779 return string_sprintf("SMTP connection from %s", hostname);
781 if (sender_host_unknown || sender_host_notsocket)
782 return string_sprintf("SMTP connection from %s", sender_ident);
785 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
787 if ((log_extra_selector & LX_incoming_interface) != 0 &&
788 interface_address != NULL)
789 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
790 interface_address, interface_port);
792 return string_sprintf("SMTP connection from %s", hostname);
797 /*************************************************
798 * Log lack of MAIL if so configured *
799 *************************************************/
801 /* This function is called when an SMTP session ends. If the log selector
802 smtp_no_mail is set, write a log line giving some details of what has happened
810 smtp_log_no_mail(void)
815 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
821 if (sender_host_authenticated != NULL)
823 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
824 if (authenticated_id != NULL)
825 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
829 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_cipher != NULL)
830 s = string_append(s, &size, &ptr, 2, US" X=", tls_cipher);
831 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
833 s = string_append(s, &size, &ptr, 2, US" CV=",
834 tls_certificate_verified? "yes":"no");
835 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_peerdn != NULL)
836 s = string_append(s, &size, &ptr, 3, US" DN=\"",
837 string_printing(tls_peerdn), US"\"");
840 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
841 US" C=..." : US" C=";
842 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
844 if (smtp_connection_had[i] != SCH_NONE)
846 s = string_append(s, &size, &ptr, 2, sep,
847 smtp_names[smtp_connection_had[i]]);
852 for (i = 0; i < smtp_ch_index; i++)
854 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
858 if (s != NULL) s[ptr] = 0; else s = US"";
859 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
860 host_and_ident(FALSE),
861 readconf_printtime(time(NULL) - smtp_connection_start), s);
866 /*************************************************
867 * Check HELO line and set sender_helo_name *
868 *************************************************/
870 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
871 the domain name of the sending host, or an ip literal in square brackets. The
872 arrgument is placed in sender_helo_name, which is in malloc store, because it
873 must persist over multiple incoming messages. If helo_accept_junk is set, this
874 host is permitted to send any old junk (needed for some broken hosts).
875 Otherwise, helo_allow_chars can be used for rogue characters in general
876 (typically people want to let in underscores).
879 s the data portion of the line (already past any white space)
881 Returns: TRUE or FALSE
885 check_helo(uschar *s)
888 uschar *end = s + Ustrlen(s);
889 BOOL yield = helo_accept_junk;
891 /* Discard any previous helo name */
893 if (sender_helo_name != NULL)
895 store_free(sender_helo_name);
896 sender_helo_name = NULL;
899 /* Skip tests if junk is permitted. */
903 /* Allow the new standard form for IPv6 address literals, namely,
904 [IPv6:....], and because someone is bound to use it, allow an equivalent
905 IPv4 form. Allow plain addresses as well. */
912 if (strncmpic(s, US"[IPv6:", 6) == 0)
913 yield = (string_is_ip_address(s+6, NULL) == 6);
914 else if (strncmpic(s, US"[IPv4:", 6) == 0)
915 yield = (string_is_ip_address(s+6, NULL) == 4);
917 yield = (string_is_ip_address(s+1, NULL) != 0);
922 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
923 that have been configured (usually underscore - sigh). */
930 if (!isalnum(*s) && *s != '.' && *s != '-' &&
931 Ustrchr(helo_allow_chars, *s) == NULL)
941 /* Save argument if OK */
943 if (yield) sender_helo_name = string_copy_malloc(start);
951 /*************************************************
952 * Extract SMTP command option *
953 *************************************************/
955 /* This function picks the next option setting off the end of smtp_cmd_data. It
956 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
957 things that can appear there.
960 name point this at the name
961 value point this at the data string
963 Returns: TRUE if found an option
967 extract_option(uschar **name, uschar **value)
970 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
971 while (isspace(*v)) v--;
974 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
975 if (*v != '=') return FALSE;
978 while(isalpha(n[-1])) n--;
980 if (n[-1] != ' ') return FALSE;
993 /*************************************************
994 * Reset for new message *
995 *************************************************/
997 /* This function is called whenever the SMTP session is reset from
998 within either of the setup functions.
1000 Argument: the stacking pool storage reset point
1005 smtp_reset(void *reset_point)
1007 store_reset(reset_point);
1008 recipients_list = NULL;
1009 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1010 raw_recipients_count = recipients_count = recipients_list_max = 0;
1011 message_linecount = 0;
1013 acl_added_headers = NULL;
1014 queue_only_policy = FALSE;
1015 rcpt_smtp_response = NULL;
1016 rcpt_smtp_response_same = TRUE;
1017 rcpt_in_progress = FALSE;
1018 deliver_freeze = FALSE; /* Can be set by ACL */
1019 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1020 fake_response = OK; /* Can be set by ACL */
1021 #ifdef WITH_CONTENT_SCAN
1022 no_mbox_unspool = FALSE; /* Can be set by ACL */
1024 submission_mode = FALSE; /* Can be set by ACL */
1025 suppress_local_fixups = FALSE; /* Can be set by ACL */
1026 active_local_from_check = local_from_check; /* Can be set by ACL */
1027 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1028 sender_address = NULL;
1029 submission_name = NULL; /* Can be set by ACL */
1030 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1031 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1032 sender_verified_list = NULL; /* No senders verified */
1033 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1034 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1035 authenticated_sender = NULL;
1036 #ifdef EXPERIMENTAL_BRIGHTMAIL
1038 bmi_verdicts = NULL;
1040 #ifdef EXPERIMENTAL_DOMAINKEYS
1043 #ifdef EXPERIMENTAL_DKIM
1046 #ifdef EXPERIMENTAL_SPF
1047 spf_header_comment = NULL;
1048 spf_received = NULL;
1050 spf_smtp_comment = NULL;
1052 body_linecount = body_zerocount = 0;
1054 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1055 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1056 /* Note that ratelimiters_conn persists across resets. */
1058 /* Reset message ACL variables */
1062 /* The message body variables use malloc store. They may be set if this is
1063 not the first message in an SMTP session and the previous message caused them
1064 to be referenced in an ACL. */
1066 if (message_body != NULL)
1068 store_free(message_body);
1069 message_body = NULL;
1072 if (message_body_end != NULL)
1074 store_free(message_body_end);
1075 message_body_end = NULL;
1078 /* Warning log messages are also saved in malloc store. They are saved to avoid
1079 repetition in the same message, but it seems right to repeat them for different
1082 while (acl_warn_logged != NULL)
1084 string_item *this = acl_warn_logged;
1085 acl_warn_logged = acl_warn_logged->next;
1094 /*************************************************
1095 * Initialize for incoming batched SMTP message *
1096 *************************************************/
1098 /* This function is called from smtp_setup_msg() in the case when
1099 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1100 of messages in one file with SMTP commands between them. All errors must be
1101 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1102 relevant. After an error on a sender, or an invalid recipient, the remainder
1103 of the message is skipped. The value of received_protocol is already set.
1106 Returns: > 0 message successfully started (reached DATA)
1107 = 0 QUIT read or end of file reached
1108 < 0 should not occur
1112 smtp_setup_batch_msg(void)
1115 void *reset_point = store_get(0);
1117 /* Save the line count at the start of each transaction - single commands
1118 like HELO and RSET count as whole transactions. */
1120 bsmtp_transaction_linecount = receive_linecount;
1122 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1124 smtp_reset(reset_point); /* Reset for start of message */
1126 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1127 value. The values are 2 larger than the required yield of the function. */
1132 uschar *recipient = NULL;
1133 int start, end, sender_domain, recipient_domain;
1135 switch(smtp_read_command(FALSE))
1137 /* The HELO/EHLO commands set sender_address_helo if they have
1138 valid data; otherwise they are ignored, except that they do
1139 a reset of the state. */
1144 check_helo(smtp_cmd_data);
1148 smtp_reset(reset_point);
1149 bsmtp_transaction_linecount = receive_linecount;
1153 /* The MAIL FROM command requires an address as an operand. All we
1154 do here is to parse it for syntactic correctness. The form "<>" is
1155 a special case which converts into an empty string. The start/end
1156 pointers in the original are not used further for this address, as
1157 it is the canonical extracted address which is all that is kept. */
1160 if (sender_address != NULL)
1161 /* The function moan_smtp_batch() does not return. */
1162 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1164 if (smtp_cmd_data[0] == 0)
1165 /* The function moan_smtp_batch() does not return. */
1166 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1168 /* Reset to start of message */
1170 smtp_reset(reset_point);
1172 /* Apply SMTP rewrite */
1174 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1175 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1176 US"", global_rewrite_rules) : smtp_cmd_data;
1178 /* Extract the address; the TRUE flag allows <> as valid */
1181 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1184 if (raw_sender == NULL)
1185 /* The function moan_smtp_batch() does not return. */
1186 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1188 sender_address = string_copy(raw_sender);
1190 /* Qualify unqualified sender addresses if permitted to do so. */
1192 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1194 if (allow_unqualified_sender)
1196 sender_address = rewrite_address_qualify(sender_address, FALSE);
1197 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1198 "and rewritten\n", raw_sender);
1200 /* The function moan_smtp_batch() does not return. */
1201 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1207 /* The RCPT TO command requires an address as an operand. All we do
1208 here is to parse it for syntactic correctness. There may be any number
1209 of RCPT TO commands, specifying multiple senders. We build them all into
1210 a data structure that is in argc/argv format. The start/end values
1211 given by parse_extract_address are not used, as we keep only the
1212 extracted address. */
1215 if (sender_address == NULL)
1216 /* The function moan_smtp_batch() does not return. */
1217 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1219 if (smtp_cmd_data[0] == 0)
1220 /* The function moan_smtp_batch() does not return. */
1221 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1223 /* Check maximum number allowed */
1225 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1226 /* The function moan_smtp_batch() does not return. */
1227 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1228 recipients_max_reject? "552": "452");
1230 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1231 recipient address */
1233 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1234 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1235 global_rewrite_rules) : smtp_cmd_data;
1237 /* rfc821_domains = TRUE; << no longer needed */
1238 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1239 &recipient_domain, FALSE);
1240 /* rfc821_domains = FALSE; << no longer needed */
1242 if (recipient == NULL)
1243 /* The function moan_smtp_batch() does not return. */
1244 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1246 /* If the recipient address is unqualified, qualify it if permitted. Then
1247 add it to the list of recipients. */
1249 if (recipient_domain == 0)
1251 if (allow_unqualified_recipient)
1253 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1255 recipient = rewrite_address_qualify(recipient, TRUE);
1257 /* The function moan_smtp_batch() does not return. */
1258 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1261 receive_add_recipient(recipient, -1);
1265 /* The DATA command is legal only if it follows successful MAIL FROM
1266 and RCPT TO commands. This function is complete when a valid DATA
1267 command is encountered. */
1270 if (sender_address == NULL || recipients_count <= 0)
1272 /* The function moan_smtp_batch() does not return. */
1273 if (sender_address == NULL)
1274 moan_smtp_batch(smtp_cmd_buffer,
1275 "503 MAIL FROM:<sender> command must precede DATA");
1277 moan_smtp_batch(smtp_cmd_buffer,
1278 "503 RCPT TO:<recipient> must precede DATA");
1282 done = 3; /* DATA successfully achieved */
1283 message_ended = END_NOTENDED; /* Indicate in middle of message */
1288 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1295 bsmtp_transaction_linecount = receive_linecount;
1306 /* The function moan_smtp_batch() does not return. */
1307 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1312 /* The function moan_smtp_batch() does not return. */
1313 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1318 /* The function moan_smtp_batch() does not return. */
1319 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1324 return done - 2; /* Convert yield values */
1330 /*************************************************
1331 * Start an SMTP session *
1332 *************************************************/
1334 /* This function is called at the start of an SMTP session. Thereafter,
1335 smtp_setup_msg() is called to initiate each separate message. This
1336 function does host-specific testing, and outputs the banner line.
1339 Returns: FALSE if the session can not continue; something has
1340 gone wrong, or the connection to the host is blocked
1344 smtp_start_session(void)
1348 uschar *user_msg, *log_msg;
1352 smtp_connection_start = time(NULL);
1353 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1354 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1357 /* Default values for certain variables */
1359 helo_seen = esmtp = helo_accept_junk = FALSE;
1360 smtp_mailcmd_count = 0;
1361 count_nonmail = TRUE_UNSET;
1362 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1363 smtp_delay_mail = smtp_rlm_base;
1364 auth_advertised = FALSE;
1365 pipelining_advertised = FALSE;
1366 pipelining_enable = TRUE;
1367 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1368 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1370 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1372 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1373 authentication settings from -oMaa to remain in force. */
1375 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1376 authenticated_by = NULL;
1379 tls_cipher = tls_peerdn = NULL;
1380 tls_advertised = FALSE;
1383 /* Reset ACL connection variables */
1387 /* Allow for trailing 0 in the command and data buffers. */
1389 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1390 if (smtp_cmd_buffer == NULL)
1391 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1392 "malloc() failed for SMTP command buffer");
1393 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1395 /* For batched input, the protocol setting can be overridden from the
1396 command line by a trusted caller. */
1398 if (smtp_batched_input)
1400 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1403 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1404 reset later if any of EHLO/AUTH/STARTTLS are received. */
1408 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1410 /* Set up the buffer for inputting using direct read() calls, and arrange to
1411 call the local functions instead of the standard C ones. */
1413 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1414 if (smtp_inbuffer == NULL)
1415 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1416 receive_getc = smtp_getc;
1417 receive_ungetc = smtp_ungetc;
1418 receive_feof = smtp_feof;
1419 receive_ferror = smtp_ferror;
1420 receive_smtp_buffered = smtp_buffered;
1421 smtp_inptr = smtp_inend = smtp_inbuffer;
1422 smtp_had_eof = smtp_had_error = 0;
1424 /* Set up the message size limit; this may be host-specific */
1426 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1427 if (expand_string_message != NULL)
1429 if (thismessage_size_limit == -1)
1430 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1431 "%s", expand_string_message);
1433 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1434 "%s", expand_string_message);
1435 smtp_closedown(US"Temporary local problem - please try later");
1439 /* When a message is input locally via the -bs or -bS options, sender_host_
1440 unknown is set unless -oMa was used to force an IP address, in which case it
1441 is checked like a real remote connection. When -bs is used from inetd, this
1442 flag is not set, causing the sending host to be checked. The code that deals
1443 with IP source routing (if configured) is never required for -bs or -bS and
1444 the flag sender_host_notsocket is used to suppress it.
1446 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1447 reserve for certain hosts and/or networks. */
1449 if (!sender_host_unknown)
1452 BOOL reserved_host = FALSE;
1454 /* Look up IP options (source routing info) on the socket if this is not an
1455 -oMa "host", and if any are found, log them and drop the connection.
1457 Linux (and others now, see below) is different to everyone else, so there
1458 has to be some conditional compilation here. Versions of Linux before 2.1.15
1459 used a structure whose name was "options". Somebody finally realized that
1460 this name was silly, and it got changed to "ip_options". I use the
1461 newer name here, but there is a fudge in the script that sets up os.h
1462 to define a macro in older Linux systems.
1464 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1465 glibc 2, which has chosen ip_opts for the structure name. This is now
1466 really a glibc thing rather than a Linux thing, so the condition name
1467 has been changed to reflect this. It is relevant also to GNU/Hurd.
1469 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1470 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1471 a special macro defined in the os.h file.
1473 Some DGUX versions on older hardware appear not to support IP options at
1474 all, so there is now a general macro which can be set to cut out this
1477 How to do this properly in IPv6 is not yet known. */
1479 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1481 #ifdef GLIBC_IP_OPTIONS
1482 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1487 #elif defined DARWIN_IP_OPTIONS
1493 if (!host_checking && !sender_host_notsocket)
1496 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1497 struct ip_options *ipopt = store_get(optlen);
1499 struct ip_opts ipoptblock;
1500 struct ip_opts *ipopt = &ipoptblock;
1501 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1503 struct ipoption ipoptblock;
1504 struct ipoption *ipopt = &ipoptblock;
1505 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1508 /* Occasional genuine failures of getsockopt() have been seen - for
1509 example, "reset by peer". Therefore, just log and give up on this
1510 call, unless the error is ENOPROTOOPT. This error is given by systems
1511 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1512 of writing. So for that error, carry on - we just can't do an IP options
1515 DEBUG(D_receive) debug_printf("checking for IP options\n");
1517 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1520 if (errno != ENOPROTOOPT)
1522 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1523 host_and_ident(FALSE), strerror(errno));
1524 smtp_printf("451 SMTP service not available\r\n");
1529 /* Deal with any IP options that are set. On the systems I have looked at,
1530 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1531 more logging data than will fit in big_buffer. Nevertheless, after somebody
1532 questioned this code, I've added in some paranoid checking. */
1534 else if (optlen > 0)
1536 uschar *p = big_buffer;
1537 uschar *pend = big_buffer + big_buffer_size;
1538 uschar *opt, *adptr;
1540 struct in_addr addr;
1543 uschar *optstart = (uschar *)(ipopt->__data);
1545 uschar *optstart = (uschar *)(ipopt->ip_opts);
1547 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1550 DEBUG(D_receive) debug_printf("IP options exist\n");
1552 Ustrcpy(p, "IP options on incoming call:");
1555 for (opt = optstart; opt != NULL &&
1556 opt < (uschar *)(ipopt) + optlen;)
1570 if (!string_format(p, pend-p, " %s [@%s",
1571 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1573 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1575 inet_ntoa(ipopt->ip_dst)))
1577 inet_ntoa(ipopt->ipopt_dst)))
1585 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1587 while (optcount-- > 0)
1589 memcpy(&addr, adptr, sizeof(addr));
1590 if (!string_format(p, pend - p - 1, "%s%s",
1591 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1597 adptr += sizeof(struct in_addr);
1606 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1609 for (i = 0; i < opt[1]; i++)
1611 sprintf(CS p, "%2.2x ", opt[i]);
1622 log_write(0, LOG_MAIN, "%s", big_buffer);
1624 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1626 log_write(0, LOG_MAIN|LOG_REJECT,
1627 "connection from %s refused (IP options)", host_and_ident(FALSE));
1629 smtp_printf("554 SMTP service not available\r\n");
1633 /* Length of options = 0 => there are no options */
1635 else DEBUG(D_receive) debug_printf("no IP options found\n");
1637 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1639 /* Set keep-alive in socket options. The option is on by default. This
1640 setting is an attempt to get rid of some hanging connections that stick in
1641 read() when the remote end (usually a dialup) goes away. */
1643 if (smtp_accept_keepalive && !sender_host_notsocket)
1644 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1646 /* If the current host matches host_lookup, set the name by doing a
1647 reverse lookup. On failure, sender_host_name will be NULL and
1648 host_lookup_failed will be TRUE. This may or may not be serious - optional
1651 if (verify_check_host(&host_lookup) == OK)
1653 (void)host_name_lookup();
1654 host_build_sender_fullhost();
1657 /* Delay this until we have the full name, if it is looked up. */
1659 set_process_info("handling incoming connection from %s",
1660 host_and_ident(FALSE));
1662 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1663 smtps port for use with older style SSL MTAs. */
1666 if (tls_on_connect &&
1667 tls_server_start(tls_require_ciphers,
1668 gnutls_require_mac, gnutls_require_kx, gnutls_require_proto) != OK)
1672 /* Test for explicit connection rejection */
1674 if (verify_check_host(&host_reject_connection) == OK)
1676 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1677 "from %s (host_reject_connection)", host_and_ident(FALSE));
1678 smtp_printf("554 SMTP service not available\r\n");
1682 /* Test with TCP Wrappers if so configured. There is a problem in that
1683 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1684 such as disks dying. In these cases, it is desirable to reject with a 4xx
1685 error instead of a 5xx error. There isn't a "right" way to detect such
1686 problems. The following kludge is used: errno is zeroed before calling
1687 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1688 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1691 #ifdef USE_TCP_WRAPPERS
1693 if (!hosts_ctl("exim",
1694 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1695 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1696 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1698 if (errno == 0 || errno == ENOENT)
1700 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1701 log_write(L_connection_reject,
1702 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1703 "(tcp wrappers)", host_and_ident(FALSE));
1704 smtp_printf("554 SMTP service not available\r\n");
1708 int save_errno = errno;
1709 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1710 "errno value %d\n", save_errno);
1711 log_write(L_connection_reject,
1712 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1713 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1714 smtp_printf("451 Temporary local problem - please try later\r\n");
1720 /* Check for reserved slots. The value of smtp_accept_count has already been
1721 incremented to include this process. */
1723 if (smtp_accept_max > 0 &&
1724 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
1726 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1728 log_write(L_connection_reject,
1729 LOG_MAIN, "temporarily refused connection from %s: not in "
1730 "reserve list: connected=%d max=%d reserve=%d%s",
1731 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
1732 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1733 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1734 "please try again later\r\n", smtp_active_hostname);
1737 reserved_host = TRUE;
1740 /* If a load level above which only messages from reserved hosts are
1741 accepted is set, check the load. For incoming calls via the daemon, the
1742 check is done in the superior process if there are no reserved hosts, to
1743 save a fork. In all cases, the load average will already be available
1744 in a global variable at this point. */
1746 if (smtp_load_reserve >= 0 &&
1747 load_average > smtp_load_reserve &&
1749 verify_check_host(&smtp_reserve_hosts) != OK)
1751 log_write(L_connection_reject,
1752 LOG_MAIN, "temporarily refused connection from %s: not in "
1753 "reserve list and load average = %.2f", host_and_ident(FALSE),
1754 (double)load_average/1000.0);
1755 smtp_printf("421 %s: Too much load; please try again later\r\n",
1756 smtp_active_hostname);
1760 /* Determine whether unqualified senders or recipients are permitted
1761 for this host. Unfortunately, we have to do this every time, in order to
1762 set the flags so that they can be inspected when considering qualifying
1763 addresses in the headers. For a site that permits no qualification, this
1764 won't take long, however. */
1766 allow_unqualified_sender =
1767 verify_check_host(&sender_unqualified_hosts) == OK;
1769 allow_unqualified_recipient =
1770 verify_check_host(&recipient_unqualified_hosts) == OK;
1772 /* Determine whether HELO/EHLO is required for this host. The requirement
1773 can be hard or soft. */
1775 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1777 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1779 /* Determine whether this hosts is permitted to send syntactic junk
1780 after a HELO or EHLO command. */
1782 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1785 /* For batch SMTP input we are now done. */
1787 if (smtp_batched_input) return TRUE;
1789 /* Run the ACL if it exists */
1792 if (acl_smtp_connect != NULL)
1795 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1799 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1804 /* Output the initial message for a two-way SMTP connection. It may contain
1805 newlines, which then cause a multi-line response to be given. */
1807 code = US"220"; /* Default status code */
1808 esc = US""; /* Default extended status code */
1809 esclen = 0; /* Length of esc */
1811 if (user_msg == NULL)
1813 s = expand_string(smtp_banner);
1815 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1816 "failed: %s", smtp_banner, expand_string_message);
1822 smtp_message_code(&code, &codelen, &s, NULL);
1826 esclen = codelen - 4;
1830 /* Remove any terminating newlines; might as well remove trailing space too */
1833 while (p > s && isspace(p[-1])) p--;
1836 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1837 is all contained in a single IP packet. The original code wrote out the
1838 greeting using several calls to fprint/fputc, and on busy servers this could
1839 cause it to be split over more than one packet - which caused CC:Mail to fall
1840 over when it got the second part of the greeting after sending its first
1841 command. Sigh. To try to avoid this, build the complete greeting message
1842 first, and output it in one fell swoop. This gives a better chance of it
1843 ending up as a single packet. */
1845 ss = store_get(size);
1849 do /* At least once, in case we have an empty string */
1852 uschar *linebreak = Ustrchr(p, '\n');
1853 ss = string_cat(ss, &size, &ptr, code, 3);
1854 if (linebreak == NULL)
1857 ss = string_cat(ss, &size, &ptr, US" ", 1);
1861 len = linebreak - p;
1862 ss = string_cat(ss, &size, &ptr, US"-", 1);
1864 ss = string_cat(ss, &size, &ptr, esc, esclen);
1865 ss = string_cat(ss, &size, &ptr, p, len);
1866 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1868 if (linebreak != NULL) p++;
1872 ss[ptr] = 0; /* string_cat leaves room for this */
1874 /* Before we write the banner, check that there is no input pending, unless
1875 this synchronisation check is disabled. */
1879 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1880 "synchronization error (input sent without waiting for greeting): "
1881 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1882 string_printing(smtp_inptr));
1883 smtp_printf("554 SMTP synchronization error\r\n");
1887 /* Now output the banner */
1889 smtp_printf("%s", ss);
1897 /*************************************************
1898 * Handle SMTP syntax and protocol errors *
1899 *************************************************/
1901 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1902 to do so. Then transmit the error response. The return value depends on the
1903 number of syntax and protocol errors in this SMTP session.
1906 type error type, given as a log flag bit
1907 code response code; <= 0 means don't send a response
1908 data data to reflect in the response (can be NULL)
1909 errmess the error message
1911 Returns: -1 limit of syntax/protocol errors NOT exceeded
1912 +1 limit of syntax/protocol errors IS exceeded
1914 These values fit in with the values of the "done" variable in the main
1915 processing loop in smtp_setup_msg(). */
1918 synprot_error(int type, int code, uschar *data, uschar *errmess)
1922 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1923 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1924 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1926 if (++synprot_error_count > smtp_max_synprot_errors)
1929 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1930 "syntax or protocol errors (last command was \"%s\")",
1931 host_and_ident(FALSE), smtp_cmd_buffer);
1936 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1937 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1939 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1948 /*************************************************
1949 * Log incomplete transactions *
1950 *************************************************/
1952 /* This function is called after a transaction has been aborted by RSET, QUIT,
1953 connection drops or other errors. It logs the envelope information received
1954 so far in order to preserve address verification attempts.
1956 Argument: string to indicate what aborted the transaction
1961 incomplete_transaction_log(uschar *what)
1963 if (sender_address == NULL || /* No transaction in progress */
1964 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1967 /* Build list of recipients for logging */
1969 if (recipients_count > 0)
1972 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1973 for (i = 0; i < recipients_count; i++)
1974 raw_recipients[i] = recipients_list[i].address;
1975 raw_recipients_count = recipients_count;
1978 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1979 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1985 /*************************************************
1986 * Send SMTP response, possibly multiline *
1987 *************************************************/
1989 /* There are, it seems, broken clients out there that cannot handle multiline
1990 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1991 output nothing for non-final calls, and only the first line for anything else.
1994 code SMTP code, may involve extended status codes
1995 codelen length of smtp code; if > 4 there's an ESC
1996 final FALSE if the last line isn't the final line
1997 msg message text, possibly containing newlines
2003 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2008 if (!final && no_multiline_responses) return;
2013 esclen = codelen - 4;
2016 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2017 have had the same. Note: this code is also present in smtp_printf(). It would
2018 be tidier to have it only in one place, but when it was added, it was easier to
2019 do it that way, so as not to have to mess with the code for the RCPT command,
2020 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2022 if (rcpt_in_progress)
2024 if (rcpt_smtp_response == NULL)
2025 rcpt_smtp_response = string_copy(msg);
2026 else if (rcpt_smtp_response_same &&
2027 Ustrcmp(rcpt_smtp_response, msg) != 0)
2028 rcpt_smtp_response_same = FALSE;
2029 rcpt_in_progress = FALSE;
2032 /* Not output the message, splitting it up into multiple lines if necessary. */
2036 uschar *nl = Ustrchr(msg, '\n');
2039 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2042 else if (nl[1] == 0 || no_multiline_responses)
2044 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2045 (int)(nl - msg), msg);
2050 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2052 while (isspace(*msg)) msg++;
2060 /*************************************************
2061 * Parse user SMTP message *
2062 *************************************************/
2064 /* This function allows for user messages overriding the response code details
2065 by providing a suitable response code string at the start of the message
2066 user_msg. Check the message for starting with a response code and optionally an
2067 extended status code. If found, check that the first digit is valid, and if so,
2068 change the code pointer and length to use the replacement. An invalid code
2069 causes a panic log; in this case, if the log messages is the same as the user
2070 message, we must also adjust the value of the log message to show the code that
2071 is actually going to be used (the original one).
2073 This function is global because it is called from receive.c as well as within
2076 Note that the code length returned includes the terminating whitespace
2077 character, which is always included in the regex match.
2080 code SMTP code, may involve extended status codes
2081 codelen length of smtp code; if > 4 there's an ESC
2083 log_msg optional log message, to be adjusted with the new SMTP code
2089 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2094 if (msg == NULL || *msg == NULL) return;
2096 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2097 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2100 if ((*msg)[0] != (*code)[0])
2102 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2103 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2104 if (log_msg != NULL && *log_msg == *msg)
2105 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2110 *codelen = ovector[1]; /* Includes final space */
2112 *msg += ovector[1]; /* Chop the code off the message */
2119 /*************************************************
2120 * Handle an ACL failure *
2121 *************************************************/
2123 /* This function is called when acl_check() fails. As well as calls from within
2124 this module, it is called from receive.c for an ACL after DATA. It sorts out
2125 logging the incident, and sets up the error response. A message containing
2126 newlines is turned into a multiline SMTP response, but for logging, only the
2129 There's a table of default permanent failure response codes to use in
2130 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2131 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2132 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2133 state, because there are broken clients that try VRFY before RCPT. A 5xx
2134 response should be given only when the address is positively known to be
2135 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2138 From Exim 4.63, it is possible to override the response code details by
2139 providing a suitable response code string at the start of the message provided
2140 in user_msg. The code's first digit is checked for validity.
2143 where where the ACL was called from
2145 user_msg a message that can be included in an SMTP response
2146 log_msg a message for logging
2148 Returns: 0 in most cases
2149 2 if the failure code was FAIL_DROP, in which case the
2150 SMTP connection should be dropped (this value fits with the
2151 "done" variable in smtp_setup_msg() below)
2155 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2157 BOOL drop = rc == FAIL_DROP;
2161 uschar *sender_info = US"";
2163 #ifdef WITH_CONTENT_SCAN
2164 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2166 (where == ACL_WHERE_PREDATA)? US"DATA" :
2167 (where == ACL_WHERE_DATA)? US"after DATA" :
2168 (smtp_cmd_data == NULL)?
2169 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2170 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2172 if (drop) rc = FAIL;
2174 /* Set the default SMTP code, and allow a user message to change it. */
2176 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2177 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2179 /* We used to have sender_address here; however, there was a bug that was not
2180 updating sender_address after a rewrite during a verify. When this bug was
2181 fixed, sender_address at this point became the rewritten address. I'm not sure
2182 this is what should be logged, so I've changed to logging the unrewritten
2183 address to retain backward compatibility. */
2185 #ifndef WITH_CONTENT_SCAN
2186 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2188 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2191 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
2192 sender_address_unrewritten : sender_address);
2195 /* If there's been a sender verification failure with a specific message, and
2196 we have not sent a response about it yet, do so now, as a preliminary line for
2197 failures, but not defers. However, always log it for defer, and log it for fail
2198 unless the sender_verify_fail log selector has been turned off. */
2200 if (sender_verified_failed != NULL &&
2201 !testflag(sender_verified_failed, af_sverify_told))
2203 BOOL save_rcpt_in_progress = rcpt_in_progress;
2204 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2206 setflag(sender_verified_failed, af_sverify_told);
2208 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2209 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2210 host_and_ident(TRUE),
2211 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2212 sender_verified_failed->address,
2213 (sender_verified_failed->message == NULL)? US"" :
2214 string_sprintf(": %s", sender_verified_failed->message));
2216 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2217 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2218 testflag(sender_verified_failed, af_verify_pmfail)?
2219 "Postmaster verification failed while checking <%s>\n%s\n"
2220 "Several RFCs state that you are required to have a postmaster\n"
2221 "mailbox for each mail domain. This host does not accept mail\n"
2222 "from domains whose servers reject the postmaster address."
2224 testflag(sender_verified_failed, af_verify_nsfail)?
2225 "Callback setup failed while verifying <%s>\n%s\n"
2226 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2227 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2228 "RFC requirements, and stops you from receiving standard bounce\n"
2229 "messages. This host does not accept mail from domains whose servers\n"
2232 "Verification failed for <%s>\n%s",
2233 sender_verified_failed->address,
2234 sender_verified_failed->user_message));
2236 rcpt_in_progress = save_rcpt_in_progress;
2239 /* Sort out text for logging */
2241 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2242 lognl = Ustrchr(log_msg, '\n');
2243 if (lognl != NULL) *lognl = 0;
2245 /* Send permanent failure response to the command, but the code used isn't
2246 always a 5xx one - see comments at the start of this function. If the original
2247 rc was FAIL_DROP we drop the connection and yield 2. */
2249 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2250 US"Administrative prohibition" : user_msg);
2252 /* Send temporary failure response to the command. Don't give any details,
2253 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2254 verb, and for a header verify when smtp_return_error_details is set.
2256 This conditional logic is all somewhat of a mess because of the odd
2257 interactions between temp_details and return_error_details. One day it should
2258 be re-implemented in a tidier fashion. */
2262 if (acl_temp_details && user_msg != NULL)
2264 if (smtp_return_error_details &&
2265 sender_verified_failed != NULL &&
2266 sender_verified_failed->message != NULL)
2268 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2270 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2273 smtp_respond(smtp_code, codelen, TRUE,
2274 US"Temporary local problem - please try later");
2277 /* Log the incident to the logs that are specified by log_reject_target
2278 (default main, reject). This can be empty to suppress logging of rejections. If
2279 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2280 is closing if required and return 2. */
2282 if (log_reject_target != 0)
2283 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2284 host_and_ident(TRUE),
2285 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2287 if (!drop) return 0;
2289 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2290 smtp_get_connection_info());
2292 /* Run the not-quit ACL, but without any custom messages. This should not be a
2293 problem, because we get here only if some other ACL has issued "drop", and
2294 in that case, *its* custom messages will have been used above. */
2296 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2303 /*************************************************
2304 * Handle SMTP exit when QUIT is not given *
2305 *************************************************/
2307 /* This function provides a logging/statistics hook for when an SMTP connection
2308 is dropped on the floor or the other end goes away. It's a global function
2309 because it's called from receive.c as well as this module. As well as running
2310 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2311 response, either with a custom message from the ACL, or using a default. There
2312 is one case, however, when no message is output - after "drop". In that case,
2313 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2314 passed to this function.
2316 In case things go wrong while processing this function, causing an error that
2317 may re-enter this funtion, there is a recursion check.
2320 reason What $smtp_notquit_reason will be set to in the ACL;
2321 if NULL, the ACL is not run
2322 code The error code to return as part of the response
2323 defaultrespond The default message if there's no user_msg
2329 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2332 uschar *user_msg = NULL;
2333 uschar *log_msg = NULL;
2335 /* Check for recursive acll */
2337 if (smtp_exit_function_called)
2339 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2343 smtp_exit_function_called = TRUE;
2345 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2347 if (acl_smtp_notquit != NULL && reason != NULL)
2349 smtp_notquit_reason = reason;
2350 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2353 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2357 /* Write an SMTP response if we are expected to give one. As the default
2358 responses are all internal, they should always fit in the buffer, but code a
2359 warning, just in case. Note that string_vformat() still leaves a complete
2360 string, even if it is incomplete. */
2362 if (code != NULL && defaultrespond != NULL)
2364 if (user_msg == NULL)
2368 va_start(ap, defaultrespond);
2369 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2370 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2371 smtp_printf("%s %s\r\n", code, buffer);
2375 smtp_respond(code, 3, TRUE, user_msg);
2383 /*************************************************
2384 * Verify HELO argument *
2385 *************************************************/
2387 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2388 matched. It is also called from ACL processing if verify = helo is used and
2389 verification was not previously tried (i.e. helo_try_verify_hosts was not
2390 matched). The result of its processing is to set helo_verified and
2391 helo_verify_failed. These variables should both be FALSE for this function to
2394 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2395 for IPv6 ::ffff: literals.
2398 Returns: TRUE if testing was completed;
2399 FALSE on a temporary failure
2403 smtp_verify_helo(void)
2407 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2410 if (sender_helo_name == NULL)
2412 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2415 /* Deal with the case of -bs without an IP address */
2417 else if (sender_host_address == NULL)
2419 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2420 helo_verified = TRUE;
2423 /* Deal with the more common case when there is a sending IP address */
2425 else if (sender_helo_name[0] == '[')
2427 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2428 Ustrlen(sender_host_address)) == 0;
2433 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2434 helo_verified = Ustrncmp(sender_helo_name + 1,
2435 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2440 { if (helo_verified) debug_printf("matched host address\n"); }
2443 /* Do a reverse lookup if one hasn't already given a positive or negative
2444 response. If that fails, or the name doesn't match, try checking with a forward
2449 if (sender_host_name == NULL && !host_lookup_failed)
2450 yield = host_name_lookup() != DEFER;
2452 /* If a host name is known, check it and all its aliases. */
2454 if (sender_host_name != NULL)
2456 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2460 HDEBUG(D_receive) debug_printf("matched host name\n");
2464 uschar **aliases = sender_host_aliases;
2465 while (*aliases != NULL)
2467 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2468 if (helo_verified) break;
2473 debug_printf("matched alias %s\n", *(--aliases));
2478 /* Final attempt: try a forward lookup of the helo name */
2484 h.name = sender_helo_name;
2488 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2490 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2491 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2496 if (Ustrcmp(hh->address, sender_host_address) == 0)
2498 helo_verified = TRUE;
2500 debug_printf("IP address for %s matches calling address\n",
2510 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2517 /*************************************************
2518 * Send user response message *
2519 *************************************************/
2521 /* This function is passed a default response code and a user message. It calls
2522 smtp_message_code() to check and possibly modify the response code, and then
2523 calls smtp_respond() to transmit the response. I put this into a function
2524 just to avoid a lot of repetition.
2527 code the response code
2528 user_msg the user message
2534 smtp_user_msg(uschar *code, uschar *user_msg)
2537 smtp_message_code(&code, &len, &user_msg, NULL);
2538 smtp_respond(code, len, TRUE, user_msg);
2544 /*************************************************
2545 * Initialize for SMTP incoming message *
2546 *************************************************/
2548 /* This function conducts the initial dialogue at the start of an incoming SMTP
2549 message, and builds a list of recipients. However, if the incoming message
2550 is part of a batch (-bS option) a separate function is called since it would
2551 be messy having tests splattered about all over this function. This function
2552 therefore handles the case where interaction is occurring. The input and output
2553 files are set up in smtp_in and smtp_out.
2555 The global recipients_list is set to point to a vector of recipient_item
2556 blocks, whose number is given by recipients_count. This is extended by the
2557 receive_add_recipient() function. The global variable sender_address is set to
2558 the sender's address. The yield is +1 if a message has been successfully
2559 started, 0 if a QUIT command was encountered or the connection was refused from
2560 the particular host, or -1 if the connection was lost.
2564 Returns: > 0 message successfully started (reached DATA)
2565 = 0 QUIT read or end of file reached or call refused
2570 smtp_setup_msg(void)
2573 BOOL toomany = FALSE;
2574 BOOL discarded = FALSE;
2575 BOOL last_was_rej_mail = FALSE;
2576 BOOL last_was_rcpt = FALSE;
2577 void *reset_point = store_get(0);
2579 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2581 /* Reset for start of new message. We allow one RSET not to be counted as a
2582 nonmail command, for those MTAs that insist on sending it between every
2583 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2584 TLS between messages (an Exim client may do this if it has messages queued up
2585 for the host). Note: we do NOT reset AUTH at this point. */
2587 smtp_reset(reset_point);
2588 message_ended = END_NOTSTARTED;
2590 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2591 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2592 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2594 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2597 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2599 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2601 /* Batched SMTP is handled in a different function. */
2603 if (smtp_batched_input) return smtp_setup_batch_msg();
2605 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2606 value. The values are 2 larger than the required yield of the function. */
2611 uschar *etrn_command;
2612 uschar *etrn_serialize_key;
2614 uschar *log_msg, *smtp_code;
2615 uschar *user_msg = NULL;
2616 uschar *recipient = NULL;
2617 uschar *hello = NULL;
2618 uschar *set_id = NULL;
2620 BOOL was_rej_mail = FALSE;
2621 BOOL was_rcpt = FALSE;
2622 void (*oldsignal)(int);
2624 int start, end, sender_domain, recipient_domain;
2629 switch(smtp_read_command(TRUE))
2631 /* The AUTH command is not permitted to occur inside a transaction, and may
2632 occur successfully only once per connection. Actually, that isn't quite
2633 true. When TLS is started, all previous information about a connection must
2634 be discarded, so a new AUTH is permitted at that time.
2636 AUTH may only be used when it has been advertised. However, it seems that
2637 there are clients that send AUTH when it hasn't been advertised, some of
2638 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2639 So there's a get-out that allows this to happen.
2641 AUTH is initially labelled as a "nonmail command" so that one occurrence
2642 doesn't get counted. We change the label here so that multiple failing
2643 AUTHS will eventually hit the nonmail threshold. */
2647 authentication_failed = TRUE;
2648 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2650 if (!auth_advertised && !allow_auth_unadvertised)
2652 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2653 US"AUTH command used when not advertised");
2656 if (sender_host_authenticated != NULL)
2658 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2659 US"already authenticated");
2662 if (sender_address != NULL)
2664 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2665 US"not permitted in mail transaction");
2671 if (acl_smtp_auth != NULL)
2673 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2676 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2681 /* Find the name of the requested authentication mechanism. */
2684 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
2686 if (!isalnum(c) && c != '-' && c != '_')
2688 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2689 US"invalid character in authentication mechanism name");
2695 /* If not at the end of the line, we must be at white space. Terminate the
2696 name and move the pointer on to any data that may be present. */
2698 if (*smtp_cmd_data != 0)
2700 *smtp_cmd_data++ = 0;
2701 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
2704 /* Search for an authentication mechanism which is configured for use
2705 as a server and which has been advertised (unless, sigh, allow_auth_
2706 unadvertised is set). */
2708 for (au = auths; au != NULL; au = au->next)
2710 if (strcmpic(s, au->public_name) == 0 && au->server &&
2711 (au->advertised || allow_auth_unadvertised)) break;
2716 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2717 string_sprintf("%s authentication mechanism not supported", s));
2721 /* Run the checking code, passing the remainder of the command line as
2722 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2723 it as the only set numerical variable. The authenticator may set $auth<n>
2724 and also set other numeric variables. The $auth<n> variables are preferred
2725 nowadays; the numerical variables remain for backwards compatibility.
2727 Afterwards, have a go at expanding the set_id string, even if
2728 authentication failed - for bad passwords it can be useful to log the
2729 userid. On success, require set_id to expand and exist, and put it in
2730 authenticated_id. Save this in permanent store, as the working store gets
2731 reset at HELO, RSET, etc. */
2733 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2735 expand_nlength[0] = 0; /* $0 contains nothing */
2737 c = (au->info->servercode)(au, smtp_cmd_data);
2738 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2739 expand_nmax = -1; /* Reset numeric variables */
2740 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2742 /* The value of authenticated_id is stored in the spool file and printed in
2743 log lines. It must not contain binary zeros or newline characters. In
2744 normal use, it never will, but when playing around or testing, this error
2745 can (did) happen. To guard against this, ensure that the id contains only
2746 printing characters. */
2748 if (set_id != NULL) set_id = string_printing(set_id);
2750 /* For the non-OK cases, set up additional logging data if set_id
2755 if (set_id != NULL && *set_id != 0)
2756 set_id = string_sprintf(" (set_id=%s)", set_id);
2760 /* Switch on the result */
2765 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2767 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2768 sender_host_authenticated = au->name;
2769 authentication_failed = FALSE;
2771 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2772 ((sender_host_address != NULL)? pnlocal : 0);
2773 s = ss = US"235 Authentication succeeded";
2774 authenticated_by = au;
2778 /* Authentication succeeded, but we failed to expand the set_id string.
2779 Treat this as a temporary error. */
2781 auth_defer_msg = expand_string_message;
2785 s = string_sprintf("435 Unable to authenticate at present%s",
2786 auth_defer_user_msg);
2787 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2788 set_id, auth_defer_msg);
2792 s = ss = US"501 Invalid base64 data";
2796 s = ss = US"501 Authentication cancelled";
2800 s = ss = US"553 Initial data not expected";
2804 s = US"535 Incorrect authentication data";
2805 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2809 s = US"435 Internal error";
2810 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2811 "check", set_id, c);
2815 smtp_printf("%s\r\n", s);
2817 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2818 au->name, host_and_ident(FALSE), ss);
2820 break; /* AUTH_CMD */
2822 /* The HELO/EHLO commands are permitted to appear in the middle of a
2823 session as well as at the beginning. They have the effect of a reset in
2824 addition to their other functions. Their absence at the start cannot be
2825 taken to be an error.
2829 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2830 or 502 failure replies MUST be returned as appropriate. The SMTP
2831 server MUST stay in the same state after transmitting these replies
2832 that it was in before the EHLO was received.
2834 Therefore, we do not do the reset until after checking the command for
2835 acceptability. This change was made for Exim release 4.11. Previously
2836 it did the reset first. */
2849 HELO_EHLO: /* Common code for HELO and EHLO */
2850 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2851 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2853 /* Reject the HELO if its argument was invalid or non-existent. A
2854 successful check causes the argument to be saved in malloc store. */
2856 if (!check_helo(smtp_cmd_data))
2858 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2860 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2861 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2862 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2863 string_printing(smtp_cmd_argument));
2865 if (++synprot_error_count > smtp_max_synprot_errors)
2867 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2868 "syntax or protocol errors (last command was \"%s\")",
2869 host_and_ident(FALSE), smtp_cmd_buffer);
2876 /* If sender_host_unknown is true, we have got here via the -bs interface,
2877 not called from inetd. Otherwise, we are running an IP connection and the
2878 host address will be set. If the helo name is the primary name of this
2879 host and we haven't done a reverse lookup, force one now. If helo_required
2880 is set, ensure that the HELO name matches the actual host. If helo_verify
2881 is set, do the same check, but softly. */
2883 if (!sender_host_unknown)
2885 BOOL old_helo_verified = helo_verified;
2886 uschar *p = smtp_cmd_data;
2888 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2891 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2892 because otherwise the log can be confusing. */
2894 if (sender_host_name == NULL &&
2895 (deliver_domain = sender_helo_name, /* set $domain */
2896 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2897 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2898 (void)host_name_lookup();
2900 /* Rebuild the fullhost info to include the HELO name (and the real name
2901 if it was looked up.) */
2903 host_build_sender_fullhost(); /* Rebuild */
2904 set_process_info("handling%s incoming connection from %s",
2905 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2907 /* Verify if configured. This doesn't give much security, but it does
2908 make some people happy to be able to do it. If helo_required is set,
2909 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2910 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2911 now obsolescent, since the verification can now be requested selectively
2914 helo_verified = helo_verify_failed = FALSE;
2915 if (helo_required || helo_verify)
2917 BOOL tempfail = !smtp_verify_helo();
2922 smtp_printf("%d %s argument does not match calling host\r\n",
2923 tempfail? 451 : 550, hello);
2924 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2925 tempfail? "temporarily " : "",
2926 hello, sender_helo_name, host_and_ident(FALSE));
2927 helo_verified = old_helo_verified;
2928 break; /* End of HELO/EHLO processing */
2930 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2931 "helo_try_verify_hosts\n", hello);
2936 #ifdef EXPERIMENTAL_SPF
2937 /* set up SPF context */
2938 spf_init(sender_helo_name, sender_host_address);
2941 /* Apply an ACL check if one is defined; afterwards, recheck
2942 synchronization in case the client started sending in a delay. */
2944 if (acl_smtp_helo != NULL)
2946 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2949 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2950 sender_helo_name = NULL;
2951 host_build_sender_fullhost(); /* Rebuild */
2954 else if (!check_sync()) goto SYNC_FAILURE;
2957 /* Generate an OK reply. The default string includes the ident if present,
2958 and also the IP address if present. Reflecting back the ident is intended
2959 as a deterrent to mail forgers. For maximum efficiency, and also because
2960 some broken systems expect each response to be in a single packet, arrange
2961 that the entire reply is sent in one write(). */
2963 auth_advertised = FALSE;
2964 pipelining_advertised = FALSE;
2966 tls_advertised = FALSE;
2969 smtp_code = US"250 "; /* Default response code plus space*/
2970 if (user_msg == NULL)
2972 s = string_sprintf("%.3s %s Hello %s%s%s",
2974 smtp_active_hostname,
2975 (sender_ident == NULL)? US"" : sender_ident,
2976 (sender_ident == NULL)? US"" : US" at ",
2977 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2982 if (sender_host_address != NULL)
2984 s = string_cat(s, &size, &ptr, US" [", 2);
2985 s = string_cat(s, &size, &ptr, sender_host_address,
2986 Ustrlen(sender_host_address));
2987 s = string_cat(s, &size, &ptr, US"]", 1);
2991 /* A user-supplied EHLO greeting may not contain more than one line. Note
2992 that the code returned by smtp_message_code() includes the terminating
2993 whitespace character. */
2999 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3000 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3001 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3003 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3004 "newlines: message truncated: %s", string_printing(s));
3011 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3013 /* If we received EHLO, we must create a multiline response which includes
3014 the functions supported. */
3020 /* I'm not entirely happy with this, as an MTA is supposed to check
3021 that it has enough room to accept a message of maximum size before
3022 it sends this. However, there seems little point in not sending it.
3023 The actual size check happens later at MAIL FROM time. By postponing it
3024 till then, VRFY and EXPN can be used after EHLO when space is short. */
3026 if (thismessage_size_limit > 0)
3028 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3029 thismessage_size_limit);
3030 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3034 s = string_cat(s, &size, &ptr, smtp_code, 3);
3035 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3038 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3039 clean; if it has an 8-bit character in its hand, it just sends it. It
3040 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3041 However, some users want this option simply in order to stop MUAs
3042 mangling messages that contain top-bit-set characters. It is therefore
3043 provided as an option. */
3045 if (accept_8bitmime)
3047 s = string_cat(s, &size, &ptr, smtp_code, 3);
3048 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3051 /* Advertise ETRN if there's an ACL checking whether a host is
3052 permitted to issue it; a check is made when any host actually tries. */
3054 if (acl_smtp_etrn != NULL)
3056 s = string_cat(s, &size, &ptr, smtp_code, 3);
3057 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3060 /* Advertise EXPN if there's an ACL checking whether a host is
3061 permitted to issue it; a check is made when any host actually tries. */
3063 if (acl_smtp_expn != NULL)
3065 s = string_cat(s, &size, &ptr, smtp_code, 3);
3066 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3069 /* Exim is quite happy with pipelining, so let the other end know that
3070 it is safe to use it, unless advertising is disabled. */
3072 if (pipelining_enable &&
3073 verify_check_host(&pipelining_advertise_hosts) == OK)
3075 s = string_cat(s, &size, &ptr, smtp_code, 3);
3076 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3077 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3078 pipelining_advertised = TRUE;
3081 /* If any server authentication mechanisms are configured, advertise
3082 them if the current host is in auth_advertise_hosts. The problem with
3083 advertising always is that some clients then require users to
3084 authenticate (and aren't configurable otherwise) even though it may not
3085 be necessary (e.g. if the host is in host_accept_relay).
3087 RFC 2222 states that SASL mechanism names contain only upper case
3088 letters, so output the names in upper case, though we actually recognize
3089 them in either case in the AUTH command. */
3093 if (verify_check_host(&auth_advertise_hosts) == OK)
3097 for (au = auths; au != NULL; au = au->next)
3099 if (au->server && (au->advertise_condition == NULL ||
3100 expand_check_condition(au->advertise_condition, au->name,
3101 US"authenticator")))
3106 s = string_cat(s, &size, &ptr, smtp_code, 3);
3107 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3109 auth_advertised = TRUE;
3112 s = string_cat(s, &size, &ptr, US" ", 1);
3113 s = string_cat(s, &size, &ptr, au->public_name,
3114 Ustrlen(au->public_name));
3115 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3116 au->advertised = TRUE;
3118 else au->advertised = FALSE;
3120 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3124 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3125 if it has been included in the binary, and the host matches
3126 tls_advertise_hosts. We must *not* advertise if we are already in a
3127 secure connection. */
3130 if (tls_active < 0 &&
3131 verify_check_host(&tls_advertise_hosts) != FAIL)
3133 s = string_cat(s, &size, &ptr, smtp_code, 3);
3134 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3135 tls_advertised = TRUE;
3139 /* Finish off the multiline reply with one that is always available. */
3141 s = string_cat(s, &size, &ptr, smtp_code, 3);
3142 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3145 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3151 if (tls_active >= 0) (void)tls_write(s, ptr); else
3154 (void)fwrite(s, 1, ptr, smtp_out);
3158 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3159 memmove(cr, cr + 1, (ptr--) - (cr - s));
3160 debug_printf("SMTP>> %s", s);
3164 /* Reset the protocol and the state, abandoning any previous message. */
3166 received_protocol = (esmtp?
3168 ((sender_host_authenticated != NULL)? pauthed : 0) +
3169 ((tls_active >= 0)? pcrpted : 0)]
3171 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
3173 ((sender_host_address != NULL)? pnlocal : 0);
3175 smtp_reset(reset_point);
3177 break; /* HELO/EHLO */
3180 /* The MAIL command requires an address as an operand. All we do
3181 here is to parse it for syntactic correctness. The form "<>" is
3182 a special case which converts into an empty string. The start/end
3183 pointers in the original are not used further for this address, as
3184 it is the canonical extracted address which is all that is kept. */
3188 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3189 was_rej_mail = TRUE; /* Reset if accepted */
3191 if (helo_required && !helo_seen)
3193 smtp_printf("503 HELO or EHLO required\r\n");
3194 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3195 "HELO/EHLO given", host_and_ident(FALSE));
3199 if (sender_address != NULL)
3201 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3202 US"sender already given");
3206 if (smtp_cmd_data[0] == 0)
3208 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3209 US"MAIL must have an address operand");
3213 /* Check to see if the limit for messages per connection would be
3214 exceeded by accepting further messages. */
3216 if (smtp_accept_max_per_connection > 0 &&
3217 smtp_mailcmd_count > smtp_accept_max_per_connection)
3219 smtp_printf("421 too many messages in this connection\r\n");
3220 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3221 "messages in one connection", host_and_ident(TRUE));
3225 /* Reset for start of message - even if this is going to fail, we
3226 obviously need to throw away any previous data. */
3228 smtp_reset(reset_point);
3230 sender_data = recipient_data = NULL;
3232 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3236 uschar *name, *value, *end;
3237 unsigned long int size;
3239 if (!extract_option(&name, &value)) break;
3241 /* Handle SIZE= by reading the value. We don't do the check till later,
3242 in order to be able to log the sender address on failure. */
3244 if (strcmpic(name, US"SIZE") == 0 &&
3245 ((size = Ustrtoul(value, &end, 10)), *end == 0))
3247 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3249 message_size = (int)size;
3252 /* If this session was initiated with EHLO and accept_8bitmime is set,
3253 Exim will have indicated that it supports the BODY=8BITMIME option. In
3254 fact, it does not support this according to the RFCs, in that it does not
3255 take any special action for forwarding messages containing 8-bit
3256 characters. That is why accept_8bitmime is not the default setting, but
3257 some sites want the action that is provided. We recognize both "8BITMIME"
3258 and "7BIT" as body types, but take no action. */
3260 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
3261 (strcmpic(value, US"8BITMIME") == 0 ||
3262 strcmpic(value, US"7BIT") == 0)) {}
3264 /* Handle the AUTH extension. If the value given is not "<>" and either
3265 the ACL says "yes" or there is no ACL but the sending host is
3266 authenticated, we set it up as the authenticated sender. However, if the
3267 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3268 the condition is met. The value of AUTH is an xtext, which means that +,
3269 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3272 else if (strcmpic(name, US"AUTH") == 0)
3274 if (Ustrcmp(value, "<>") != 0)
3279 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3281 /* Put back terminator overrides for error message */
3284 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3285 US"invalid data for AUTH");
3289 if (acl_smtp_mailauth == NULL)
3291 ignore_msg = US"client not authenticated";
3292 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3296 ignore_msg = US"rejected by ACL";
3297 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3298 &user_msg, &log_msg);
3304 if (authenticated_by == NULL ||
3305 authenticated_by->mail_auth_condition == NULL ||
3306 expand_check_condition(authenticated_by->mail_auth_condition,
3307 authenticated_by->name, US"authenticator"))
3308 break; /* Accept the AUTH */
3310 ignore_msg = US"server_mail_auth_condition failed";
3311 if (authenticated_id != NULL)
3312 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3313 ignore_msg, authenticated_id);
3318 authenticated_sender = NULL;
3319 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3320 value, host_and_ident(TRUE), ignore_msg);
3323 /* Should only get DEFER or ERROR here. Put back terminator
3324 overrides for error message */
3329 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3336 /* Unknown option. Stick back the terminator characters and break
3337 the loop. An error for a malformed address will occur. */
3347 /* If we have passed the threshold for rate limiting, apply the current
3348 delay, and update it for next time, provided this is a limited host. */
3350 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3351 verify_check_host(&smtp_ratelimit_hosts) == OK)
3353 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3354 smtp_delay_mail/1000.0);
3355 millisleep((int)smtp_delay_mail);
3356 smtp_delay_mail *= smtp_rlm_factor;
3357 if (smtp_delay_mail > (double)smtp_rlm_limit)
3358 smtp_delay_mail = (double)smtp_rlm_limit;
3361 /* Now extract the address, first applying any SMTP-time rewriting. The
3362 TRUE flag allows "<>" as a sender address. */
3364 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3365 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3366 global_rewrite_rules) : smtp_cmd_data;
3368 /* rfc821_domains = TRUE; << no longer needed */
3370 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3372 /* rfc821_domains = FALSE; << no longer needed */
3374 if (raw_sender == NULL)
3376 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3380 sender_address = raw_sender;
3382 /* If there is a configured size limit for mail, check that this message
3383 doesn't exceed it. The check is postponed to this point so that the sender
3386 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3388 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3389 log_write(L_size_reject,
3390 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3391 "message too big: size%s=%d max=%d",
3393 host_and_ident(TRUE),
3394 (message_size == INT_MAX)? ">" : "",
3396 thismessage_size_limit);
3397 sender_address = NULL;
3401 /* Check there is enough space on the disk unless configured not to.
3402 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3403 plus the current message - i.e. we accept the message only if it won't
3404 reduce the space below the threshold. Add 5000 to the size to allow for
3405 overheads such as the Received: line and storing of recipients, etc.
3406 By putting the check here, even when SIZE is not given, it allow VRFY
3407 and EXPN etc. to be used when space is short. */
3409 if (!receive_check_fs(
3410 (smtp_check_spool_space && message_size >= 0)?
3411 message_size + 5000 : 0))
3413 smtp_printf("452 Space shortage, please try later\r\n");
3414 sender_address = NULL;
3418 /* If sender_address is unqualified, reject it, unless this is a locally
3419 generated message, or the sending host or net is permitted to send
3420 unqualified addresses - typically local machines behaving as MUAs -
3421 in which case just qualify the address. The flag is set above at the start
3422 of the SMTP connection. */
3424 if (sender_domain == 0 && sender_address[0] != 0)
3426 if (allow_unqualified_sender)
3428 sender_domain = Ustrlen(sender_address) + 1;
3429 sender_address = rewrite_address_qualify(sender_address, FALSE);
3430 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3435 smtp_printf("501 %s: sender address must contain a domain\r\n",
3437 log_write(L_smtp_syntax_error,
3438 LOG_MAIN|LOG_REJECT,
3439 "unqualified sender rejected: <%s> %s%s",
3441 host_and_ident(TRUE),
3443 sender_address = NULL;
3448 /* Apply an ACL check if one is defined, before responding. Afterwards,
3449 when pipelining is not advertised, do another sync check in case the ACL
3450 delayed and the client started sending in the meantime. */
3452 if (acl_smtp_mail == NULL) rc = OK; else
3454 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3455 if (rc == OK && !pipelining_advertised && !check_sync())
3459 if (rc == OK || rc == DISCARD)
3461 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3462 else smtp_user_msg(US"250", user_msg);
3463 smtp_delay_rcpt = smtp_rlr_base;
3464 recipients_discarded = (rc == DISCARD);
3465 was_rej_mail = FALSE;
3469 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3470 sender_address = NULL;
3475 /* The RCPT command requires an address as an operand. There may be any
3476 number of RCPT commands, specifying multiple recipients. We build them all
3477 into a data structure. The start/end values given by parse_extract_address
3478 are not used, as we keep only the extracted address. */
3483 was_rcpt = rcpt_in_progress = TRUE;
3485 /* There must be a sender address; if the sender was rejected and
3486 pipelining was advertised, we assume the client was pipelining, and do not
3487 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3488 get the same treatment. */
3490 if (sender_address == NULL)
3492 if (pipelining_advertised && last_was_rej_mail)
3494 smtp_printf("503 sender not yet given\r\n");
3495 was_rej_mail = TRUE;
3499 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3500 US"sender not yet given");
3501 was_rcpt = FALSE; /* Not a valid RCPT */
3507 /* Check for an operand */
3509 if (smtp_cmd_data[0] == 0)
3511 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3512 US"RCPT must have an address operand");
3517 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3518 as a recipient address */
3520 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3521 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3522 global_rewrite_rules) : smtp_cmd_data;
3524 /* rfc821_domains = TRUE; << no longer needed */
3525 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3526 &recipient_domain, FALSE);
3527 /* rfc821_domains = FALSE; << no longer needed */
3529 if (recipient == NULL)
3531 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3536 /* If the recipient address is unqualified, reject it, unless this is a
3537 locally generated message. However, unqualified addresses are permitted
3538 from a configured list of hosts and nets - typically when behaving as
3539 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3540 really. The flag is set at the start of the SMTP connection.
3542 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3543 assumed this meant "reserved local part", but the revision of RFC 821 and
3544 friends now makes it absolutely clear that it means *mailbox*. Consequently
3545 we must always qualify this address, regardless. */
3547 if (recipient_domain == 0)
3549 if (allow_unqualified_recipient ||
3550 strcmpic(recipient, US"postmaster") == 0)
3552 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3554 recipient_domain = Ustrlen(recipient) + 1;
3555 recipient = rewrite_address_qualify(recipient, TRUE);
3560 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3562 log_write(L_smtp_syntax_error,
3563 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3564 "<%s> %s%s", recipient, host_and_ident(TRUE),
3570 /* Check maximum allowed */
3572 if (rcpt_count > recipients_max && recipients_max > 0)
3574 if (recipients_max_reject)
3577 smtp_printf("552 too many recipients\r\n");
3579 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3580 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3585 smtp_printf("452 too many recipients\r\n");
3587 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3588 "temporarily rejected: sender=<%s> %s", sender_address,
3589 host_and_ident(TRUE));
3596 /* If we have passed the threshold for rate limiting, apply the current
3597 delay, and update it for next time, provided this is a limited host. */
3599 if (rcpt_count > smtp_rlr_threshold &&
3600 verify_check_host(&smtp_ratelimit_hosts) == OK)
3602 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3603 smtp_delay_rcpt/1000.0);
3604 millisleep((int)smtp_delay_rcpt);
3605 smtp_delay_rcpt *= smtp_rlr_factor;
3606 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3607 smtp_delay_rcpt = (double)smtp_rlr_limit;
3610 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3611 for them. Otherwise, check the access control list for this recipient. As
3612 there may be a delay in this, re-check for a synchronization error
3613 afterwards, unless pipelining was advertised. */
3615 if (recipients_discarded) rc = DISCARD; else
3617 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
3619 if (rc == OK && !pipelining_advertised && !check_sync())
3623 /* The ACL was happy */
3627 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3628 else smtp_user_msg(US"250", user_msg);
3629 receive_add_recipient(recipient, -1);
3632 /* The recipient was discarded */
3634 else if (rc == DISCARD)
3636 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3637 else smtp_user_msg(US"250", user_msg);
3640 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3641 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3642 (sender_address_unrewritten != NULL)?
3643 sender_address_unrewritten : sender_address,
3644 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3645 (log_msg == NULL)? US"" : US": ",
3646 (log_msg == NULL)? US"" : log_msg);
3649 /* Either the ACL failed the address, or it was deferred. */
3653 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3654 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3659 /* The DATA command is legal only if it follows successful MAIL FROM
3660 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3661 not counted as a protocol error if it follows RCPT (which must have been
3662 rejected if there are no recipients.) This function is complete when a
3663 valid DATA command is encountered.
3665 Note concerning the code used: RFC 2821 says this:
3667 - If there was no MAIL, or no RCPT, command, or all such commands
3668 were rejected, the server MAY return a "command out of sequence"
3669 (503) or "no valid recipients" (554) reply in response to the
3672 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3673 because it is the same whether pipelining is in use or not.
3675 If all the RCPT commands that precede DATA provoked the same error message
3676 (often indicating some kind of system error), it is helpful to include it
3677 with the DATA rejection (an idea suggested by Tony Finch). */
3681 if (!discarded && recipients_count <= 0)
3683 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
3685 uschar *code = US"503";
3686 int len = Ustrlen(rcpt_smtp_response);
3687 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
3689 /* Responses from smtp_printf() will have \r\n on the end */
3690 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
3691 rcpt_smtp_response[len-2] = 0;
3692 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
3694 if (pipelining_advertised && last_was_rcpt)
3695 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
3697 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3698 US"valid RCPT command must precede DATA");
3702 if (toomany && recipients_max_reject)
3704 sender_address = NULL; /* This will allow a new MAIL without RSET */
3705 sender_address_unrewritten = NULL;
3706 smtp_printf("554 Too many recipients\r\n");
3710 /* If there is an ACL, re-check the synchronization afterwards, since the
3711 ACL may have delayed. */
3713 if (acl_smtp_predata == NULL) rc = OK; else
3715 enable_dollar_recipients = TRUE;
3716 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3718 enable_dollar_recipients = FALSE;
3719 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
3724 if (user_msg == NULL)
3725 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3726 else smtp_user_msg(US"354", user_msg);
3728 message_ended = END_NOTENDED; /* Indicate in middle of data */
3731 /* Either the ACL failed the address, or it was deferred. */
3734 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3740 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3742 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3748 /* rfc821_domains = TRUE; << no longer needed */
3749 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
3750 &recipient_domain, FALSE);
3751 /* rfc821_domains = FALSE; << no longer needed */
3753 if (address == NULL)
3754 s = string_sprintf("501 %s", errmess);
3757 address_item *addr = deliver_make_addr(address, FALSE);
3758 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3759 -1, -1, NULL, NULL, NULL))
3762 s = string_sprintf("250 <%s> is deliverable", address);
3766 s = (addr->user_message != NULL)?
3767 string_sprintf("451 <%s> %s", address, addr->user_message) :
3768 string_sprintf("451 Cannot resolve <%s> at this time", address);
3772 s = (addr->user_message != NULL)?
3773 string_sprintf("550 <%s> %s", address, addr->user_message) :
3774 string_sprintf("550 <%s> is not deliverable", address);
3775 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3776 smtp_cmd_argument, host_and_ident(TRUE));
3781 smtp_printf("%s\r\n", s);
3788 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3790 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3793 BOOL save_log_testing_mode = log_testing_mode;
3794 address_test_mode = log_testing_mode = TRUE;
3795 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
3796 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3798 address_test_mode = FALSE;
3799 log_testing_mode = save_log_testing_mode; /* true for -bh */
3808 if (!tls_advertised)
3810 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3811 US"STARTTLS command used when not advertised");
3815 /* Apply an ACL check if one is defined */
3817 if (acl_smtp_starttls != NULL)
3819 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3823 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3828 /* RFC 2487 is not clear on when this command may be sent, though it
3829 does state that all information previously obtained from the client
3830 must be discarded if a TLS session is started. It seems reasonble to
3831 do an implied RSET when STARTTLS is received. */
3833 incomplete_transaction_log(US"STARTTLS");
3834 smtp_reset(reset_point);
3836 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3838 /* Attempt to start up a TLS session, and if successful, discard all
3839 knowledge that was obtained previously. At least, that's what the RFC says,
3840 and that's what happens by default. However, in order to work round YAEB,
3841 there is an option to remember the esmtp state. Sigh.
3843 We must allow for an extra EHLO command and an extra AUTH command after
3844 STARTTLS that don't add to the nonmail command count. */
3846 if ((rc = tls_server_start(tls_require_ciphers, gnutls_require_mac,
3847 gnutls_require_kx, gnutls_require_proto)) == OK)
3849 if (!tls_remember_esmtp)
3850 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3851 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3852 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3853 if (sender_helo_name != NULL)
3855 store_free(sender_helo_name);
3856 sender_helo_name = NULL;
3857 host_build_sender_fullhost(); /* Rebuild */
3858 set_process_info("handling incoming TLS connection from %s",
3859 host_and_ident(FALSE));
3861 received_protocol = (esmtp?
3862 protocols[pextend + pcrpted +
3863 ((sender_host_authenticated != NULL)? pauthed : 0)]
3865 protocols[pnormal + pcrpted])
3867 ((sender_host_address != NULL)? pnlocal : 0);
3869 sender_host_authenticated = NULL;
3870 authenticated_id = NULL;
3871 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3872 DEBUG(D_tls) debug_printf("TLS active\n");
3873 break; /* Successful STARTTLS */
3876 /* Some local configuration problem was discovered before actually trying
3877 to do a TLS handshake; give a temporary error. */
3879 else if (rc == DEFER)
3881 smtp_printf("454 TLS currently unavailable\r\n");
3885 /* Hard failure. Reject everything except QUIT or closed connection. One
3886 cause for failure is a nested STARTTLS, in which case tls_active remains
3887 set, but we must still reject all incoming commands. */
3889 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3892 switch(smtp_read_command(FALSE))
3895 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3896 smtp_get_connection_info());
3897 smtp_notquit_exit(US"tls-failed", NULL, NULL);
3901 /* It is perhaps arguable as to which exit ACL should be called here,
3902 but as it is probably a situtation that almost never arises, it
3903 probably doesn't matter. We choose to call the real QUIT ACL, which in
3904 some sense is perhaps "right". */
3908 if (acl_smtp_quit != NULL)
3910 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
3913 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3916 if (user_msg == NULL)
3917 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3919 smtp_respond(US"221", 3, TRUE, user_msg);
3920 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3921 smtp_get_connection_info());
3926 smtp_printf("554 Security failure\r\n");
3935 /* The ACL for QUIT is provided for gathering statistical information or
3936 similar; it does not affect the response code, but it can supply a custom
3941 incomplete_transaction_log(US"QUIT");
3942 if (acl_smtp_quit != NULL)
3944 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
3946 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3949 if (user_msg == NULL)
3950 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3952 smtp_respond(US"221", 3, TRUE, user_msg);
3959 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3960 smtp_get_connection_info());
3966 incomplete_transaction_log(US"RSET");
3967 smtp_reset(reset_point);
3969 smtp_printf("250 Reset OK\r\n");
3970 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3976 smtp_printf("250 OK\r\n");
3980 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
3981 used, a check will be done for permitted hosts. Show STARTTLS only if not
3982 already in a TLS session and if it would be advertised in the EHLO
3987 smtp_printf("214-Commands supported:\r\n");
3991 Ustrcat(buffer, " AUTH");
3993 if (tls_active < 0 &&
3994 verify_check_host(&tls_advertise_hosts) != FAIL)
3995 Ustrcat(buffer, " STARTTLS");
3997 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3998 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3999 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4000 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4001 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4002 smtp_printf("214%s\r\n", buffer);
4008 incomplete_transaction_log(US"connection lost");
4009 smtp_notquit_exit(US"connection-lost", US"421",
4010 US"%s lost input connection", smtp_active_hostname);
4012 /* Don't log by default unless in the middle of a message, as some mailers
4013 just drop the call rather than sending QUIT, and it clutters up the logs.
4016 if (sender_address != NULL || recipients_count > 0)
4017 log_write(L_lost_incoming_connection,
4019 "unexpected %s while reading SMTP command from %s%s",
4020 sender_host_unknown? "EOF" : "disconnection",
4021 host_and_ident(FALSE), smtp_read_error);
4023 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4024 smtp_get_connection_info(), smtp_read_error);
4032 if (sender_address != NULL)
4034 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4035 US"ETRN is not permitted inside a transaction");
4039 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4040 host_and_ident(FALSE));
4042 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4045 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4049 /* Compute the serialization key for this command. */
4051 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4053 /* If a command has been specified for running as a result of ETRN, we
4054 permit any argument to ETRN. If not, only the # standard form is permitted,
4055 since that is strictly the only kind of ETRN that can be implemented
4056 according to the RFC. */
4058 if (smtp_etrn_command != NULL)
4062 etrn_command = smtp_etrn_command;
4063 deliver_domain = smtp_cmd_data;
4064 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4065 US"ETRN processing", &error);
4066 deliver_domain = NULL;
4069 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4071 smtp_printf("458 Internal failure\r\n");
4076 /* Else set up to call Exim with the -R option. */
4080 if (*smtp_cmd_data++ != '#')
4082 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4083 US"argument must begin with #");
4086 etrn_command = US"exim -R";
4087 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4091 /* If we are host-testing, don't actually do anything. */
4097 debug_printf("ETRN command is: %s\n", etrn_command);
4098 debug_printf("ETRN command execution skipped\n");
4100 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4101 else smtp_user_msg(US"250", user_msg);
4106 /* If ETRN queue runs are to be serialized, check the database to
4107 ensure one isn't already running. */
4109 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4111 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4115 /* Fork a child process and run the command. We don't want to have to
4116 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4117 forking. It should be set that way anyway for external incoming SMTP,
4118 but we save and restore to be tidy. If serialization is required, we
4119 actually run the command in yet another process, so we can wait for it
4120 to complete and then remove the serialization lock. */
4122 oldsignal = signal(SIGCHLD, SIG_IGN);
4124 if ((pid = fork()) == 0)
4126 smtp_input = FALSE; /* This process is not associated with the */
4127 (void)fclose(smtp_in); /* SMTP call any more. */
4128 (void)fclose(smtp_out);
4130 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
4132 /* If not serializing, do the exec right away. Otherwise, fork down
4133 into another process. */
4135 if (!smtp_etrn_serialize || (pid = fork()) == 0)
4137 DEBUG(D_exec) debug_print_argv(argv);
4138 exim_nullstd(); /* Ensure std{in,out,err} exist */
4139 execv(CS argv[0], (char *const *)argv);
4140 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
4141 etrn_command, strerror(errno));
4142 _exit(EXIT_FAILURE); /* paranoia */
4145 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4146 is, we are in the first subprocess, after forking again. All we can do
4147 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4148 complete, before removing the serialization. */
4151 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4152 "failed: %s", strerror(errno));
4156 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4158 (void)wait(&status);
4159 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4163 enq_end(etrn_serialize_key);
4164 _exit(EXIT_SUCCESS);
4167 /* Back in the top level SMTP process. Check that we started a subprocess
4168 and restore the signal state. */
4172 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4174 smtp_printf("458 Unable to fork process\r\n");
4175 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4179 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4180 else smtp_user_msg(US"250", user_msg);
4183 signal(SIGCHLD, oldsignal);
4188 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4189 US"unexpected argument data");
4193 /* This currently happens only for NULLs, but could be extended. */
4196 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
4197 US"NULL character(s) present (shown as '?')");
4198 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
4204 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
4205 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
4206 c = smtp_inend - smtp_inptr;
4207 if (c > 150) c = 150;
4209 incomplete_transaction_log(US"sync failure");
4210 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
4211 "(next input sent too soon: pipelining was%s advertised): "
4212 "rejected \"%s\" %s next input=\"%s\"",
4213 pipelining_advertised? "" : " not",
4214 smtp_cmd_buffer, host_and_ident(TRUE),
4215 string_printing(smtp_inptr));
4216 smtp_notquit_exit(US"synchronization-error", US"554",
4217 US"SMTP synchronization error");
4218 done = 1; /* Pretend eof - drops connection */
4222 case TOO_MANY_NONMAIL_CMD:
4223 s = smtp_cmd_buffer;
4224 while (*s != 0 && !isspace(*s)) s++;
4225 incomplete_transaction_log(US"too many non-mail commands");
4226 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4227 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
4228 s - smtp_cmd_buffer, smtp_cmd_buffer);
4229 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
4230 done = 1; /* Pretend eof - drops connection */
4235 if (unknown_command_count++ >= smtp_max_unknown_commands)
4237 log_write(L_smtp_syntax_error, LOG_MAIN,
4238 "SMTP syntax error in \"%s\" %s %s",
4239 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
4240 US"unrecognized command");
4241 incomplete_transaction_log(US"unrecognized command");
4242 smtp_notquit_exit(US"bad-commands", US"500",
4243 US"Too many unrecognized commands");
4245 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4246 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
4250 done = synprot_error(L_smtp_syntax_error, 500, NULL,
4251 US"unrecognized command");
4255 /* This label is used by goto's inside loops that want to break out to
4256 the end of the command-processing loop. */
4259 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
4260 last_was_rcpt = was_rcpt; /* protocol error handling */
4264 return done - 2; /* Convert yield values */
4267 /* End of smtp_in.c */
git://git.exim.org / exim.git / blob