1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.63.2.1 2009/02/24 15:57:55 tom Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2007 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. */
42 #define smtp_cmd_buffer_size 2048
44 /* Size of buffer for reading SMTP incoming packets */
46 #define in_buffer_size 8192
48 /* Structure for SMTP command list */
55 short int is_mail_cmd;
58 /* Codes for identifying commands. We order them so that those that come first
59 are those for which synchronization is always required. Checking this can help
63 /* These commands are required to be synchronized, i.e. to be the last in a
64 block of commands when pipelining. */
66 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
67 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
68 ETRN_CMD, /* This by analogy with TURN from the RFC */
69 STARTTLS_CMD, /* Required by the STARTTLS RFC */
71 /* This is a dummy to identify the non-sync commands when pipelining */
73 NON_SYNC_CMD_PIPELINING,
75 /* These commands need not be synchronized when pipelining */
77 MAIL_CMD, RCPT_CMD, RSET_CMD,
79 /* This is a dummy to identify the non-sync commands when not pipelining */
81 NON_SYNC_CMD_NON_PIPELINING,
83 /* I have been unable to find a statement about the use of pipelining
84 with AUTH, so to be on the safe side it is here, though I kind of feel
85 it should be up there with the synchronized commands. */
89 /* I'm not sure about these, but I don't think they matter. */
93 /* These are specials that don't correspond to actual commands */
95 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
96 TOO_MANY_NONMAIL_CMD };
99 /* This is a convenience macro for adding the identity of an SMTP command
100 to the circular buffer that holds a list of the last n received. */
103 smtp_connection_had[smtp_ch_index++] = n; \
104 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
107 /*************************************************
108 * Local static variables *
109 *************************************************/
111 static auth_instance *authenticated_by;
112 static BOOL auth_advertised;
114 static BOOL tls_advertised;
117 static BOOL helo_required = FALSE;
118 static BOOL helo_verify = FALSE;
119 static BOOL helo_seen;
120 static BOOL helo_accept_junk;
121 static BOOL count_nonmail;
122 static BOOL pipelining_advertised;
123 static BOOL rcpt_smtp_response_same;
124 static BOOL rcpt_in_progress;
125 static int nonmail_command_count;
126 static BOOL smtp_exit_function_called = 0;
127 static int synprot_error_count;
128 static int unknown_command_count;
129 static int sync_cmd_limit;
130 static int smtp_write_error = 0;
132 static uschar *rcpt_smtp_response;
133 static uschar *smtp_data_buffer;
134 static uschar *smtp_cmd_data;
136 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
137 final fields of all except AUTH are forced TRUE at the start of a new message
138 setup, to allow one of each between messages that is not counted as a nonmail
139 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
140 allow a new EHLO after starting up TLS.
142 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
143 counted. However, the flag is changed when AUTH is received, so that multiple
144 failing AUTHs will eventually hit the limit. After a successful AUTH, another
145 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
146 forced TRUE, to allow for the re-authentication that can happen at that point.
148 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
149 count of non-mail commands and possibly provoke an error. */
151 static smtp_cmd_list cmd_list[] = {
152 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
153 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
154 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
155 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
157 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
160 /* If you change anything above here, also fix the definitions below. */
162 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
163 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
164 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
165 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
166 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
167 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
168 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
169 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
170 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
173 static smtp_cmd_list *cmd_list_end =
174 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
176 #define CMD_LIST_RSET 0
177 #define CMD_LIST_HELO 1
178 #define CMD_LIST_EHLO 2
179 #define CMD_LIST_AUTH 3
180 #define CMD_LIST_STARTTLS 4
182 /* This list of names is used for performing the smtp_no_mail logging action.
183 It must be kept in step with the SCH_xxx enumerations. */
185 static uschar *smtp_names[] =
187 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
188 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
191 static uschar *protocols[] = {
192 US"local-smtp", /* HELO */
193 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
194 US"local-esmtp", /* EHLO */
195 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
196 US"local-esmtpa", /* EHLO->AUTH */
197 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
202 #define pcrpted 1 /* added to pextend or pnormal */
203 #define pauthed 2 /* added to pextend */
204 #define pnlocal 6 /* offset to remove "local" */
206 /* When reading SMTP from a remote host, we have to use our own versions of the
207 C input-reading functions, in order to be able to flush the SMTP output only
208 when about to read more data from the socket. This is the only way to get
209 optimal performance when the client is using pipelining. Flushing for every
210 command causes a separate packet and reply packet each time; saving all the
211 responses up (when pipelining) combines them into one packet and one response.
213 For simplicity, these functions are used for *all* SMTP input, not only when
214 receiving over a socket. However, after setting up a secure socket (SSL), input
215 is read via the OpenSSL library, and another set of functions is used instead
218 These functions are set in the receive_getc etc. variables and called with the
219 same interface as the C functions. However, since there can only ever be
220 one incoming SMTP call, we just use a single buffer and flags. There is no need
221 to implement a complicated private FILE-like structure.*/
223 static uschar *smtp_inbuffer;
224 static uschar *smtp_inptr;
225 static uschar *smtp_inend;
226 static int smtp_had_eof;
227 static int smtp_had_error;
230 /*************************************************
231 * SMTP version of getc() *
232 *************************************************/
234 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
235 it flushes the output, and refills the buffer, with a timeout. The signal
236 handler is set appropriately by the calling function. This function is not used
237 after a connection has negotated itself into an TLS/SSL state.
240 Returns: the next character or EOF
246 if (smtp_inptr >= smtp_inend)
250 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
251 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
256 /* Must put the error text in fixed store, because this might be during
257 header reading, where it releases unused store above the header. */
260 smtp_had_error = save_errno;
261 smtp_read_error = string_copy_malloc(
262 string_sprintf(" (error: %s)", strerror(save_errno)));
264 else smtp_had_eof = 1;
267 smtp_inend = smtp_inbuffer + rc;
268 smtp_inptr = smtp_inbuffer;
270 return *smtp_inptr++;
275 /*************************************************
276 * SMTP version of ungetc() *
277 *************************************************/
279 /* Puts a character back in the input buffer. Only ever
285 Returns: the character
291 *(--smtp_inptr) = ch;
298 /*************************************************
299 * SMTP version of feof() *
300 *************************************************/
302 /* Tests for a previous EOF
305 Returns: non-zero if the eof flag is set
317 /*************************************************
318 * SMTP version of ferror() *
319 *************************************************/
321 /* Tests for a previous read error, and returns with errno
322 restored to what it was when the error was detected.
325 Returns: non-zero if the error flag is set
331 errno = smtp_had_error;
332 return smtp_had_error;
337 /*************************************************
338 * Test for characters in the SMTP buffer *
339 *************************************************/
341 /* Used at the end of a message
350 return smtp_inptr < smtp_inend;
355 /*************************************************
356 * Write formatted string to SMTP channel *
357 *************************************************/
359 /* This is a separate function so that we don't have to repeat everything for
360 TLS support or debugging. It is global so that the daemon and the
361 authentication functions can use it. It does not return any error indication,
362 because major problems such as dropped connections won't show up till an output
363 flush for non-TLS connections. The smtp_fflush() function is available for
364 checking that: for convenience, TLS output errors are remembered here so that
365 they are also picked up later by smtp_fflush().
369 ... optional arguments
375 smtp_printf(char *format, ...)
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 #ifndef DISABLE_DKIM
1043 #ifdef EXPERIMENTAL_SPF
1044 spf_header_comment = NULL;
1045 spf_received = NULL;
1047 spf_smtp_comment = NULL;
1049 body_linecount = body_zerocount = 0;
1051 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1052 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1053 /* Note that ratelimiters_conn persists across resets. */
1055 /* Reset message ACL variables */
1059 /* The message body variables use malloc store. They may be set if this is
1060 not the first message in an SMTP session and the previous message caused them
1061 to be referenced in an ACL. */
1063 if (message_body != NULL)
1065 store_free(message_body);
1066 message_body = NULL;
1069 if (message_body_end != NULL)
1071 store_free(message_body_end);
1072 message_body_end = NULL;
1075 /* Warning log messages are also saved in malloc store. They are saved to avoid
1076 repetition in the same message, but it seems right to repeat them for different
1079 while (acl_warn_logged != NULL)
1081 string_item *this = acl_warn_logged;
1082 acl_warn_logged = acl_warn_logged->next;
1091 /*************************************************
1092 * Initialize for incoming batched SMTP message *
1093 *************************************************/
1095 /* This function is called from smtp_setup_msg() in the case when
1096 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1097 of messages in one file with SMTP commands between them. All errors must be
1098 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1099 relevant. After an error on a sender, or an invalid recipient, the remainder
1100 of the message is skipped. The value of received_protocol is already set.
1103 Returns: > 0 message successfully started (reached DATA)
1104 = 0 QUIT read or end of file reached
1105 < 0 should not occur
1109 smtp_setup_batch_msg(void)
1112 void *reset_point = store_get(0);
1114 /* Save the line count at the start of each transaction - single commands
1115 like HELO and RSET count as whole transactions. */
1117 bsmtp_transaction_linecount = receive_linecount;
1119 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1121 smtp_reset(reset_point); /* Reset for start of message */
1123 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1124 value. The values are 2 larger than the required yield of the function. */
1129 uschar *recipient = NULL;
1130 int start, end, sender_domain, recipient_domain;
1132 switch(smtp_read_command(FALSE))
1134 /* The HELO/EHLO commands set sender_address_helo if they have
1135 valid data; otherwise they are ignored, except that they do
1136 a reset of the state. */
1141 check_helo(smtp_cmd_data);
1145 smtp_reset(reset_point);
1146 bsmtp_transaction_linecount = receive_linecount;
1150 /* The MAIL FROM command requires an address as an operand. All we
1151 do here is to parse it for syntactic correctness. The form "<>" is
1152 a special case which converts into an empty string. The start/end
1153 pointers in the original are not used further for this address, as
1154 it is the canonical extracted address which is all that is kept. */
1157 if (sender_address != NULL)
1158 /* The function moan_smtp_batch() does not return. */
1159 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1161 if (smtp_cmd_data[0] == 0)
1162 /* The function moan_smtp_batch() does not return. */
1163 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1165 /* Reset to start of message */
1167 smtp_reset(reset_point);
1169 /* Apply SMTP rewrite */
1171 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1172 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1173 US"", global_rewrite_rules) : smtp_cmd_data;
1175 /* Extract the address; the TRUE flag allows <> as valid */
1178 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1181 if (raw_sender == NULL)
1182 /* The function moan_smtp_batch() does not return. */
1183 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1185 sender_address = string_copy(raw_sender);
1187 /* Qualify unqualified sender addresses if permitted to do so. */
1189 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1191 if (allow_unqualified_sender)
1193 sender_address = rewrite_address_qualify(sender_address, FALSE);
1194 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1195 "and rewritten\n", raw_sender);
1197 /* The function moan_smtp_batch() does not return. */
1198 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1204 /* The RCPT TO command requires an address as an operand. All we do
1205 here is to parse it for syntactic correctness. There may be any number
1206 of RCPT TO commands, specifying multiple senders. We build them all into
1207 a data structure that is in argc/argv format. The start/end values
1208 given by parse_extract_address are not used, as we keep only the
1209 extracted address. */
1212 if (sender_address == NULL)
1213 /* The function moan_smtp_batch() does not return. */
1214 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1216 if (smtp_cmd_data[0] == 0)
1217 /* The function moan_smtp_batch() does not return. */
1218 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1220 /* Check maximum number allowed */
1222 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1223 /* The function moan_smtp_batch() does not return. */
1224 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1225 recipients_max_reject? "552": "452");
1227 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1228 recipient address */
1230 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1231 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1232 global_rewrite_rules) : smtp_cmd_data;
1234 /* rfc821_domains = TRUE; << no longer needed */
1235 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1236 &recipient_domain, FALSE);
1237 /* rfc821_domains = FALSE; << no longer needed */
1239 if (recipient == NULL)
1240 /* The function moan_smtp_batch() does not return. */
1241 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1243 /* If the recipient address is unqualified, qualify it if permitted. Then
1244 add it to the list of recipients. */
1246 if (recipient_domain == 0)
1248 if (allow_unqualified_recipient)
1250 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1252 recipient = rewrite_address_qualify(recipient, TRUE);
1254 /* The function moan_smtp_batch() does not return. */
1255 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1258 receive_add_recipient(recipient, -1);
1262 /* The DATA command is legal only if it follows successful MAIL FROM
1263 and RCPT TO commands. This function is complete when a valid DATA
1264 command is encountered. */
1267 if (sender_address == NULL || recipients_count <= 0)
1269 /* The function moan_smtp_batch() does not return. */
1270 if (sender_address == NULL)
1271 moan_smtp_batch(smtp_cmd_buffer,
1272 "503 MAIL FROM:<sender> command must precede DATA");
1274 moan_smtp_batch(smtp_cmd_buffer,
1275 "503 RCPT TO:<recipient> must precede DATA");
1279 done = 3; /* DATA successfully achieved */
1280 message_ended = END_NOTENDED; /* Indicate in middle of message */
1285 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1292 bsmtp_transaction_linecount = receive_linecount;
1303 /* The function moan_smtp_batch() does not return. */
1304 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1309 /* The function moan_smtp_batch() does not return. */
1310 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1315 /* The function moan_smtp_batch() does not return. */
1316 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1321 return done - 2; /* Convert yield values */
1327 /*************************************************
1328 * Start an SMTP session *
1329 *************************************************/
1331 /* This function is called at the start of an SMTP session. Thereafter,
1332 smtp_setup_msg() is called to initiate each separate message. This
1333 function does host-specific testing, and outputs the banner line.
1336 Returns: FALSE if the session can not continue; something has
1337 gone wrong, or the connection to the host is blocked
1341 smtp_start_session(void)
1345 uschar *user_msg, *log_msg;
1349 smtp_connection_start = time(NULL);
1350 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1351 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1354 /* Default values for certain variables */
1356 helo_seen = esmtp = helo_accept_junk = FALSE;
1357 smtp_mailcmd_count = 0;
1358 count_nonmail = TRUE_UNSET;
1359 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1360 smtp_delay_mail = smtp_rlm_base;
1361 auth_advertised = FALSE;
1362 pipelining_advertised = FALSE;
1363 pipelining_enable = TRUE;
1364 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1365 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1367 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1369 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1370 authentication settings from -oMaa to remain in force. */
1372 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1373 authenticated_by = NULL;
1376 tls_cipher = tls_peerdn = NULL;
1377 tls_advertised = FALSE;
1380 /* Reset ACL connection variables */
1384 /* Allow for trailing 0 in the command and data buffers. */
1386 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1387 if (smtp_cmd_buffer == NULL)
1388 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1389 "malloc() failed for SMTP command buffer");
1390 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1392 /* For batched input, the protocol setting can be overridden from the
1393 command line by a trusted caller. */
1395 if (smtp_batched_input)
1397 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1400 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1401 reset later if any of EHLO/AUTH/STARTTLS are received. */
1405 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1407 /* Set up the buffer for inputting using direct read() calls, and arrange to
1408 call the local functions instead of the standard C ones. */
1410 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1411 if (smtp_inbuffer == NULL)
1412 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1413 receive_getc = smtp_getc;
1414 receive_ungetc = smtp_ungetc;
1415 receive_feof = smtp_feof;
1416 receive_ferror = smtp_ferror;
1417 receive_smtp_buffered = smtp_buffered;
1418 smtp_inptr = smtp_inend = smtp_inbuffer;
1419 smtp_had_eof = smtp_had_error = 0;
1421 /* Set up the message size limit; this may be host-specific */
1423 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1424 if (expand_string_message != NULL)
1426 if (thismessage_size_limit == -1)
1427 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1428 "%s", expand_string_message);
1430 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1431 "%s", expand_string_message);
1432 smtp_closedown(US"Temporary local problem - please try later");
1436 /* When a message is input locally via the -bs or -bS options, sender_host_
1437 unknown is set unless -oMa was used to force an IP address, in which case it
1438 is checked like a real remote connection. When -bs is used from inetd, this
1439 flag is not set, causing the sending host to be checked. The code that deals
1440 with IP source routing (if configured) is never required for -bs or -bS and
1441 the flag sender_host_notsocket is used to suppress it.
1443 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1444 reserve for certain hosts and/or networks. */
1446 if (!sender_host_unknown)
1449 BOOL reserved_host = FALSE;
1451 /* Look up IP options (source routing info) on the socket if this is not an
1452 -oMa "host", and if any are found, log them and drop the connection.
1454 Linux (and others now, see below) is different to everyone else, so there
1455 has to be some conditional compilation here. Versions of Linux before 2.1.15
1456 used a structure whose name was "options". Somebody finally realized that
1457 this name was silly, and it got changed to "ip_options". I use the
1458 newer name here, but there is a fudge in the script that sets up os.h
1459 to define a macro in older Linux systems.
1461 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1462 glibc 2, which has chosen ip_opts for the structure name. This is now
1463 really a glibc thing rather than a Linux thing, so the condition name
1464 has been changed to reflect this. It is relevant also to GNU/Hurd.
1466 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1467 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1468 a special macro defined in the os.h file.
1470 Some DGUX versions on older hardware appear not to support IP options at
1471 all, so there is now a general macro which can be set to cut out this
1474 How to do this properly in IPv6 is not yet known. */
1476 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1478 #ifdef GLIBC_IP_OPTIONS
1479 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1484 #elif defined DARWIN_IP_OPTIONS
1490 if (!host_checking && !sender_host_notsocket)
1493 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1494 struct ip_options *ipopt = store_get(optlen);
1496 struct ip_opts ipoptblock;
1497 struct ip_opts *ipopt = &ipoptblock;
1498 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1500 struct ipoption ipoptblock;
1501 struct ipoption *ipopt = &ipoptblock;
1502 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1505 /* Occasional genuine failures of getsockopt() have been seen - for
1506 example, "reset by peer". Therefore, just log and give up on this
1507 call, unless the error is ENOPROTOOPT. This error is given by systems
1508 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1509 of writing. So for that error, carry on - we just can't do an IP options
1512 DEBUG(D_receive) debug_printf("checking for IP options\n");
1514 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1517 if (errno != ENOPROTOOPT)
1519 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1520 host_and_ident(FALSE), strerror(errno));
1521 smtp_printf("451 SMTP service not available\r\n");
1526 /* Deal with any IP options that are set. On the systems I have looked at,
1527 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1528 more logging data than will fit in big_buffer. Nevertheless, after somebody
1529 questioned this code, I've added in some paranoid checking. */
1531 else if (optlen > 0)
1533 uschar *p = big_buffer;
1534 uschar *pend = big_buffer + big_buffer_size;
1535 uschar *opt, *adptr;
1537 struct in_addr addr;
1540 uschar *optstart = (uschar *)(ipopt->__data);
1542 uschar *optstart = (uschar *)(ipopt->ip_opts);
1544 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1547 DEBUG(D_receive) debug_printf("IP options exist\n");
1549 Ustrcpy(p, "IP options on incoming call:");
1552 for (opt = optstart; opt != NULL &&
1553 opt < (uschar *)(ipopt) + optlen;)
1567 if (!string_format(p, pend-p, " %s [@%s",
1568 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1570 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1572 inet_ntoa(ipopt->ip_dst)))
1574 inet_ntoa(ipopt->ipopt_dst)))
1582 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1584 while (optcount-- > 0)
1586 memcpy(&addr, adptr, sizeof(addr));
1587 if (!string_format(p, pend - p - 1, "%s%s",
1588 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1594 adptr += sizeof(struct in_addr);
1603 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1606 for (i = 0; i < opt[1]; i++)
1608 sprintf(CS p, "%2.2x ", opt[i]);
1619 log_write(0, LOG_MAIN, "%s", big_buffer);
1621 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1623 log_write(0, LOG_MAIN|LOG_REJECT,
1624 "connection from %s refused (IP options)", host_and_ident(FALSE));
1626 smtp_printf("554 SMTP service not available\r\n");
1630 /* Length of options = 0 => there are no options */
1632 else DEBUG(D_receive) debug_printf("no IP options found\n");
1634 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1636 /* Set keep-alive in socket options. The option is on by default. This
1637 setting is an attempt to get rid of some hanging connections that stick in
1638 read() when the remote end (usually a dialup) goes away. */
1640 if (smtp_accept_keepalive && !sender_host_notsocket)
1641 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1643 /* If the current host matches host_lookup, set the name by doing a
1644 reverse lookup. On failure, sender_host_name will be NULL and
1645 host_lookup_failed will be TRUE. This may or may not be serious - optional
1648 if (verify_check_host(&host_lookup) == OK)
1650 (void)host_name_lookup();
1651 host_build_sender_fullhost();
1654 /* Delay this until we have the full name, if it is looked up. */
1656 set_process_info("handling incoming connection from %s",
1657 host_and_ident(FALSE));
1659 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1660 smtps port for use with older style SSL MTAs. */
1663 if (tls_on_connect &&
1664 tls_server_start(tls_require_ciphers,
1665 gnutls_require_mac, gnutls_require_kx, gnutls_require_proto) != OK)
1669 /* Test for explicit connection rejection */
1671 if (verify_check_host(&host_reject_connection) == OK)
1673 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1674 "from %s (host_reject_connection)", host_and_ident(FALSE));
1675 smtp_printf("554 SMTP service not available\r\n");
1679 /* Test with TCP Wrappers if so configured. There is a problem in that
1680 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1681 such as disks dying. In these cases, it is desirable to reject with a 4xx
1682 error instead of a 5xx error. There isn't a "right" way to detect such
1683 problems. The following kludge is used: errno is zeroed before calling
1684 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1685 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1688 #ifdef USE_TCP_WRAPPERS
1690 if (!hosts_ctl("exim",
1691 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1692 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1693 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1695 if (errno == 0 || errno == ENOENT)
1697 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1698 log_write(L_connection_reject,
1699 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1700 "(tcp wrappers)", host_and_ident(FALSE));
1701 smtp_printf("554 SMTP service not available\r\n");
1705 int save_errno = errno;
1706 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1707 "errno value %d\n", save_errno);
1708 log_write(L_connection_reject,
1709 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1710 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1711 smtp_printf("451 Temporary local problem - please try later\r\n");
1717 /* Check for reserved slots. The value of smtp_accept_count has already been
1718 incremented to include this process. */
1720 if (smtp_accept_max > 0 &&
1721 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
1723 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1725 log_write(L_connection_reject,
1726 LOG_MAIN, "temporarily refused connection from %s: not in "
1727 "reserve list: connected=%d max=%d reserve=%d%s",
1728 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
1729 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1730 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1731 "please try again later\r\n", smtp_active_hostname);
1734 reserved_host = TRUE;
1737 /* If a load level above which only messages from reserved hosts are
1738 accepted is set, check the load. For incoming calls via the daemon, the
1739 check is done in the superior process if there are no reserved hosts, to
1740 save a fork. In all cases, the load average will already be available
1741 in a global variable at this point. */
1743 if (smtp_load_reserve >= 0 &&
1744 load_average > smtp_load_reserve &&
1746 verify_check_host(&smtp_reserve_hosts) != OK)
1748 log_write(L_connection_reject,
1749 LOG_MAIN, "temporarily refused connection from %s: not in "
1750 "reserve list and load average = %.2f", host_and_ident(FALSE),
1751 (double)load_average/1000.0);
1752 smtp_printf("421 %s: Too much load; please try again later\r\n",
1753 smtp_active_hostname);
1757 /* Determine whether unqualified senders or recipients are permitted
1758 for this host. Unfortunately, we have to do this every time, in order to
1759 set the flags so that they can be inspected when considering qualifying
1760 addresses in the headers. For a site that permits no qualification, this
1761 won't take long, however. */
1763 allow_unqualified_sender =
1764 verify_check_host(&sender_unqualified_hosts) == OK;
1766 allow_unqualified_recipient =
1767 verify_check_host(&recipient_unqualified_hosts) == OK;
1769 /* Determine whether HELO/EHLO is required for this host. The requirement
1770 can be hard or soft. */
1772 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1774 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1776 /* Determine whether this hosts is permitted to send syntactic junk
1777 after a HELO or EHLO command. */
1779 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1782 /* For batch SMTP input we are now done. */
1784 if (smtp_batched_input) return TRUE;
1786 /* Run the ACL if it exists */
1789 if (acl_smtp_connect != NULL)
1792 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1796 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1801 /* Output the initial message for a two-way SMTP connection. It may contain
1802 newlines, which then cause a multi-line response to be given. */
1804 code = US"220"; /* Default status code */
1805 esc = US""; /* Default extended status code */
1806 esclen = 0; /* Length of esc */
1808 if (user_msg == NULL)
1810 s = expand_string(smtp_banner);
1812 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1813 "failed: %s", smtp_banner, expand_string_message);
1819 smtp_message_code(&code, &codelen, &s, NULL);
1823 esclen = codelen - 4;
1827 /* Remove any terminating newlines; might as well remove trailing space too */
1830 while (p > s && isspace(p[-1])) p--;
1833 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1834 is all contained in a single IP packet. The original code wrote out the
1835 greeting using several calls to fprint/fputc, and on busy servers this could
1836 cause it to be split over more than one packet - which caused CC:Mail to fall
1837 over when it got the second part of the greeting after sending its first
1838 command. Sigh. To try to avoid this, build the complete greeting message
1839 first, and output it in one fell swoop. This gives a better chance of it
1840 ending up as a single packet. */
1842 ss = store_get(size);
1846 do /* At least once, in case we have an empty string */
1849 uschar *linebreak = Ustrchr(p, '\n');
1850 ss = string_cat(ss, &size, &ptr, code, 3);
1851 if (linebreak == NULL)
1854 ss = string_cat(ss, &size, &ptr, US" ", 1);
1858 len = linebreak - p;
1859 ss = string_cat(ss, &size, &ptr, US"-", 1);
1861 ss = string_cat(ss, &size, &ptr, esc, esclen);
1862 ss = string_cat(ss, &size, &ptr, p, len);
1863 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1865 if (linebreak != NULL) p++;
1869 ss[ptr] = 0; /* string_cat leaves room for this */
1871 /* Before we write the banner, check that there is no input pending, unless
1872 this synchronisation check is disabled. */
1876 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1877 "synchronization error (input sent without waiting for greeting): "
1878 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1879 string_printing(smtp_inptr));
1880 smtp_printf("554 SMTP synchronization error\r\n");
1884 /* Now output the banner */
1886 smtp_printf("%s", ss);
1894 /*************************************************
1895 * Handle SMTP syntax and protocol errors *
1896 *************************************************/
1898 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1899 to do so. Then transmit the error response. The return value depends on the
1900 number of syntax and protocol errors in this SMTP session.
1903 type error type, given as a log flag bit
1904 code response code; <= 0 means don't send a response
1905 data data to reflect in the response (can be NULL)
1906 errmess the error message
1908 Returns: -1 limit of syntax/protocol errors NOT exceeded
1909 +1 limit of syntax/protocol errors IS exceeded
1911 These values fit in with the values of the "done" variable in the main
1912 processing loop in smtp_setup_msg(). */
1915 synprot_error(int type, int code, uschar *data, uschar *errmess)
1919 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1920 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1921 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1923 if (++synprot_error_count > smtp_max_synprot_errors)
1926 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1927 "syntax or protocol errors (last command was \"%s\")",
1928 host_and_ident(FALSE), smtp_cmd_buffer);
1933 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1934 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1936 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1945 /*************************************************
1946 * Log incomplete transactions *
1947 *************************************************/
1949 /* This function is called after a transaction has been aborted by RSET, QUIT,
1950 connection drops or other errors. It logs the envelope information received
1951 so far in order to preserve address verification attempts.
1953 Argument: string to indicate what aborted the transaction
1958 incomplete_transaction_log(uschar *what)
1960 if (sender_address == NULL || /* No transaction in progress */
1961 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1964 /* Build list of recipients for logging */
1966 if (recipients_count > 0)
1969 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1970 for (i = 0; i < recipients_count; i++)
1971 raw_recipients[i] = recipients_list[i].address;
1972 raw_recipients_count = recipients_count;
1975 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1976 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1982 /*************************************************
1983 * Send SMTP response, possibly multiline *
1984 *************************************************/
1986 /* There are, it seems, broken clients out there that cannot handle multiline
1987 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1988 output nothing for non-final calls, and only the first line for anything else.
1991 code SMTP code, may involve extended status codes
1992 codelen length of smtp code; if > 4 there's an ESC
1993 final FALSE if the last line isn't the final line
1994 msg message text, possibly containing newlines
2000 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2005 if (!final && no_multiline_responses) return;
2010 esclen = codelen - 4;
2013 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2014 have had the same. Note: this code is also present in smtp_printf(). It would
2015 be tidier to have it only in one place, but when it was added, it was easier to
2016 do it that way, so as not to have to mess with the code for the RCPT command,
2017 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2019 if (rcpt_in_progress)
2021 if (rcpt_smtp_response == NULL)
2022 rcpt_smtp_response = string_copy(msg);
2023 else if (rcpt_smtp_response_same &&
2024 Ustrcmp(rcpt_smtp_response, msg) != 0)
2025 rcpt_smtp_response_same = FALSE;
2026 rcpt_in_progress = FALSE;
2029 /* Not output the message, splitting it up into multiple lines if necessary. */
2033 uschar *nl = Ustrchr(msg, '\n');
2036 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2039 else if (nl[1] == 0 || no_multiline_responses)
2041 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2042 (int)(nl - msg), msg);
2047 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2049 while (isspace(*msg)) msg++;
2057 /*************************************************
2058 * Parse user SMTP message *
2059 *************************************************/
2061 /* This function allows for user messages overriding the response code details
2062 by providing a suitable response code string at the start of the message
2063 user_msg. Check the message for starting with a response code and optionally an
2064 extended status code. If found, check that the first digit is valid, and if so,
2065 change the code pointer and length to use the replacement. An invalid code
2066 causes a panic log; in this case, if the log messages is the same as the user
2067 message, we must also adjust the value of the log message to show the code that
2068 is actually going to be used (the original one).
2070 This function is global because it is called from receive.c as well as within
2073 Note that the code length returned includes the terminating whitespace
2074 character, which is always included in the regex match.
2077 code SMTP code, may involve extended status codes
2078 codelen length of smtp code; if > 4 there's an ESC
2080 log_msg optional log message, to be adjusted with the new SMTP code
2086 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2091 if (msg == NULL || *msg == NULL) return;
2093 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2094 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2097 if ((*msg)[0] != (*code)[0])
2099 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2100 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2101 if (log_msg != NULL && *log_msg == *msg)
2102 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2107 *codelen = ovector[1]; /* Includes final space */
2109 *msg += ovector[1]; /* Chop the code off the message */
2116 /*************************************************
2117 * Handle an ACL failure *
2118 *************************************************/
2120 /* This function is called when acl_check() fails. As well as calls from within
2121 this module, it is called from receive.c for an ACL after DATA. It sorts out
2122 logging the incident, and sets up the error response. A message containing
2123 newlines is turned into a multiline SMTP response, but for logging, only the
2126 There's a table of default permanent failure response codes to use in
2127 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2128 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2129 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2130 state, because there are broken clients that try VRFY before RCPT. A 5xx
2131 response should be given only when the address is positively known to be
2132 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2135 From Exim 4.63, it is possible to override the response code details by
2136 providing a suitable response code string at the start of the message provided
2137 in user_msg. The code's first digit is checked for validity.
2140 where where the ACL was called from
2142 user_msg a message that can be included in an SMTP response
2143 log_msg a message for logging
2145 Returns: 0 in most cases
2146 2 if the failure code was FAIL_DROP, in which case the
2147 SMTP connection should be dropped (this value fits with the
2148 "done" variable in smtp_setup_msg() below)
2152 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2154 BOOL drop = rc == FAIL_DROP;
2158 uschar *sender_info = US"";
2160 #ifdef WITH_CONTENT_SCAN
2161 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2163 (where == ACL_WHERE_PREDATA)? US"DATA" :
2164 (where == ACL_WHERE_DATA)? US"after DATA" :
2165 (smtp_cmd_data == NULL)?
2166 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2167 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2169 if (drop) rc = FAIL;
2171 /* Set the default SMTP code, and allow a user message to change it. */
2173 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2174 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2176 /* We used to have sender_address here; however, there was a bug that was not
2177 updating sender_address after a rewrite during a verify. When this bug was
2178 fixed, sender_address at this point became the rewritten address. I'm not sure
2179 this is what should be logged, so I've changed to logging the unrewritten
2180 address to retain backward compatibility. */
2182 #ifndef WITH_CONTENT_SCAN
2183 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2185 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2188 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
2189 sender_address_unrewritten : sender_address);
2192 /* If there's been a sender verification failure with a specific message, and
2193 we have not sent a response about it yet, do so now, as a preliminary line for
2194 failures, but not defers. However, always log it for defer, and log it for fail
2195 unless the sender_verify_fail log selector has been turned off. */
2197 if (sender_verified_failed != NULL &&
2198 !testflag(sender_verified_failed, af_sverify_told))
2200 BOOL save_rcpt_in_progress = rcpt_in_progress;
2201 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2203 setflag(sender_verified_failed, af_sverify_told);
2205 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2206 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2207 host_and_ident(TRUE),
2208 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2209 sender_verified_failed->address,
2210 (sender_verified_failed->message == NULL)? US"" :
2211 string_sprintf(": %s", sender_verified_failed->message));
2213 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2214 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2215 testflag(sender_verified_failed, af_verify_pmfail)?
2216 "Postmaster verification failed while checking <%s>\n%s\n"
2217 "Several RFCs state that you are required to have a postmaster\n"
2218 "mailbox for each mail domain. This host does not accept mail\n"
2219 "from domains whose servers reject the postmaster address."
2221 testflag(sender_verified_failed, af_verify_nsfail)?
2222 "Callback setup failed while verifying <%s>\n%s\n"
2223 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2224 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2225 "RFC requirements, and stops you from receiving standard bounce\n"
2226 "messages. This host does not accept mail from domains whose servers\n"
2229 "Verification failed for <%s>\n%s",
2230 sender_verified_failed->address,
2231 sender_verified_failed->user_message));
2233 rcpt_in_progress = save_rcpt_in_progress;
2236 /* Sort out text for logging */
2238 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2239 lognl = Ustrchr(log_msg, '\n');
2240 if (lognl != NULL) *lognl = 0;
2242 /* Send permanent failure response to the command, but the code used isn't
2243 always a 5xx one - see comments at the start of this function. If the original
2244 rc was FAIL_DROP we drop the connection and yield 2. */
2246 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2247 US"Administrative prohibition" : user_msg);
2249 /* Send temporary failure response to the command. Don't give any details,
2250 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2251 verb, and for a header verify when smtp_return_error_details is set.
2253 This conditional logic is all somewhat of a mess because of the odd
2254 interactions between temp_details and return_error_details. One day it should
2255 be re-implemented in a tidier fashion. */
2259 if (acl_temp_details && user_msg != NULL)
2261 if (smtp_return_error_details &&
2262 sender_verified_failed != NULL &&
2263 sender_verified_failed->message != NULL)
2265 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2267 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2270 smtp_respond(smtp_code, codelen, TRUE,
2271 US"Temporary local problem - please try later");
2274 /* Log the incident to the logs that are specified by log_reject_target
2275 (default main, reject). This can be empty to suppress logging of rejections. If
2276 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2277 is closing if required and return 2. */
2279 if (log_reject_target != 0)
2280 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2281 host_and_ident(TRUE),
2282 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2284 if (!drop) return 0;
2286 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2287 smtp_get_connection_info());
2289 /* Run the not-quit ACL, but without any custom messages. This should not be a
2290 problem, because we get here only if some other ACL has issued "drop", and
2291 in that case, *its* custom messages will have been used above. */
2293 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2300 /*************************************************
2301 * Handle SMTP exit when QUIT is not given *
2302 *************************************************/
2304 /* This function provides a logging/statistics hook for when an SMTP connection
2305 is dropped on the floor or the other end goes away. It's a global function
2306 because it's called from receive.c as well as this module. As well as running
2307 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2308 response, either with a custom message from the ACL, or using a default. There
2309 is one case, however, when no message is output - after "drop". In that case,
2310 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2311 passed to this function.
2313 In case things go wrong while processing this function, causing an error that
2314 may re-enter this funtion, there is a recursion check.
2317 reason What $smtp_notquit_reason will be set to in the ACL;
2318 if NULL, the ACL is not run
2319 code The error code to return as part of the response
2320 defaultrespond The default message if there's no user_msg
2326 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2329 uschar *user_msg = NULL;
2330 uschar *log_msg = NULL;
2332 /* Check for recursive acll */
2334 if (smtp_exit_function_called)
2336 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2340 smtp_exit_function_called = TRUE;
2342 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2344 if (acl_smtp_notquit != NULL && reason != NULL)
2346 smtp_notquit_reason = reason;
2347 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2350 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2354 /* Write an SMTP response if we are expected to give one. As the default
2355 responses are all internal, they should always fit in the buffer, but code a
2356 warning, just in case. Note that string_vformat() still leaves a complete
2357 string, even if it is incomplete. */
2359 if (code != NULL && defaultrespond != NULL)
2361 if (user_msg == NULL)
2365 va_start(ap, defaultrespond);
2366 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2367 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2368 smtp_printf("%s %s\r\n", code, buffer);
2372 smtp_respond(code, 3, TRUE, user_msg);
2380 /*************************************************
2381 * Verify HELO argument *
2382 *************************************************/
2384 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2385 matched. It is also called from ACL processing if verify = helo is used and
2386 verification was not previously tried (i.e. helo_try_verify_hosts was not
2387 matched). The result of its processing is to set helo_verified and
2388 helo_verify_failed. These variables should both be FALSE for this function to
2391 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2392 for IPv6 ::ffff: literals.
2395 Returns: TRUE if testing was completed;
2396 FALSE on a temporary failure
2400 smtp_verify_helo(void)
2404 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2407 if (sender_helo_name == NULL)
2409 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2412 /* Deal with the case of -bs without an IP address */
2414 else if (sender_host_address == NULL)
2416 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2417 helo_verified = TRUE;
2420 /* Deal with the more common case when there is a sending IP address */
2422 else if (sender_helo_name[0] == '[')
2424 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2425 Ustrlen(sender_host_address)) == 0;
2430 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2431 helo_verified = Ustrncmp(sender_helo_name + 1,
2432 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2437 { if (helo_verified) debug_printf("matched host address\n"); }
2440 /* Do a reverse lookup if one hasn't already given a positive or negative
2441 response. If that fails, or the name doesn't match, try checking with a forward
2446 if (sender_host_name == NULL && !host_lookup_failed)
2447 yield = host_name_lookup() != DEFER;
2449 /* If a host name is known, check it and all its aliases. */
2451 if (sender_host_name != NULL)
2453 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2457 HDEBUG(D_receive) debug_printf("matched host name\n");
2461 uschar **aliases = sender_host_aliases;
2462 while (*aliases != NULL)
2464 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2465 if (helo_verified) break;
2470 debug_printf("matched alias %s\n", *(--aliases));
2475 /* Final attempt: try a forward lookup of the helo name */
2481 h.name = sender_helo_name;
2485 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2487 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2488 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2493 if (Ustrcmp(hh->address, sender_host_address) == 0)
2495 helo_verified = TRUE;
2497 debug_printf("IP address for %s matches calling address\n",
2507 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2514 /*************************************************
2515 * Send user response message *
2516 *************************************************/
2518 /* This function is passed a default response code and a user message. It calls
2519 smtp_message_code() to check and possibly modify the response code, and then
2520 calls smtp_respond() to transmit the response. I put this into a function
2521 just to avoid a lot of repetition.
2524 code the response code
2525 user_msg the user message
2531 smtp_user_msg(uschar *code, uschar *user_msg)
2534 smtp_message_code(&code, &len, &user_msg, NULL);
2535 smtp_respond(code, len, TRUE, user_msg);
2541 /*************************************************
2542 * Initialize for SMTP incoming message *
2543 *************************************************/
2545 /* This function conducts the initial dialogue at the start of an incoming SMTP
2546 message, and builds a list of recipients. However, if the incoming message
2547 is part of a batch (-bS option) a separate function is called since it would
2548 be messy having tests splattered about all over this function. This function
2549 therefore handles the case where interaction is occurring. The input and output
2550 files are set up in smtp_in and smtp_out.
2552 The global recipients_list is set to point to a vector of recipient_item
2553 blocks, whose number is given by recipients_count. This is extended by the
2554 receive_add_recipient() function. The global variable sender_address is set to
2555 the sender's address. The yield is +1 if a message has been successfully
2556 started, 0 if a QUIT command was encountered or the connection was refused from
2557 the particular host, or -1 if the connection was lost.
2561 Returns: > 0 message successfully started (reached DATA)
2562 = 0 QUIT read or end of file reached or call refused
2567 smtp_setup_msg(void)
2570 BOOL toomany = FALSE;
2571 BOOL discarded = FALSE;
2572 BOOL last_was_rej_mail = FALSE;
2573 BOOL last_was_rcpt = FALSE;
2574 void *reset_point = store_get(0);
2576 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2578 /* Reset for start of new message. We allow one RSET not to be counted as a
2579 nonmail command, for those MTAs that insist on sending it between every
2580 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2581 TLS between messages (an Exim client may do this if it has messages queued up
2582 for the host). Note: we do NOT reset AUTH at this point. */
2584 smtp_reset(reset_point);
2585 message_ended = END_NOTSTARTED;
2587 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2588 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2589 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2591 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2594 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2596 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2598 /* Batched SMTP is handled in a different function. */
2600 if (smtp_batched_input) return smtp_setup_batch_msg();
2602 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2603 value. The values are 2 larger than the required yield of the function. */
2608 uschar *etrn_command;
2609 uschar *etrn_serialize_key;
2611 uschar *log_msg, *smtp_code;
2612 uschar *user_msg = NULL;
2613 uschar *recipient = NULL;
2614 uschar *hello = NULL;
2615 uschar *set_id = NULL;
2617 BOOL was_rej_mail = FALSE;
2618 BOOL was_rcpt = FALSE;
2619 void (*oldsignal)(int);
2621 int start, end, sender_domain, recipient_domain;
2626 switch(smtp_read_command(TRUE))
2628 /* The AUTH command is not permitted to occur inside a transaction, and may
2629 occur successfully only once per connection. Actually, that isn't quite
2630 true. When TLS is started, all previous information about a connection must
2631 be discarded, so a new AUTH is permitted at that time.
2633 AUTH may only be used when it has been advertised. However, it seems that
2634 there are clients that send AUTH when it hasn't been advertised, some of
2635 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2636 So there's a get-out that allows this to happen.
2638 AUTH is initially labelled as a "nonmail command" so that one occurrence
2639 doesn't get counted. We change the label here so that multiple failing
2640 AUTHS will eventually hit the nonmail threshold. */
2644 authentication_failed = TRUE;
2645 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2647 if (!auth_advertised && !allow_auth_unadvertised)
2649 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2650 US"AUTH command used when not advertised");
2653 if (sender_host_authenticated != NULL)
2655 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2656 US"already authenticated");
2659 if (sender_address != NULL)
2661 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2662 US"not permitted in mail transaction");
2668 if (acl_smtp_auth != NULL)
2670 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2673 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2678 /* Find the name of the requested authentication mechanism. */
2681 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
2683 if (!isalnum(c) && c != '-' && c != '_')
2685 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2686 US"invalid character in authentication mechanism name");
2692 /* If not at the end of the line, we must be at white space. Terminate the
2693 name and move the pointer on to any data that may be present. */
2695 if (*smtp_cmd_data != 0)
2697 *smtp_cmd_data++ = 0;
2698 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
2701 /* Search for an authentication mechanism which is configured for use
2702 as a server and which has been advertised (unless, sigh, allow_auth_
2703 unadvertised is set). */
2705 for (au = auths; au != NULL; au = au->next)
2707 if (strcmpic(s, au->public_name) == 0 && au->server &&
2708 (au->advertised || allow_auth_unadvertised)) break;
2713 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2714 string_sprintf("%s authentication mechanism not supported", s));
2718 /* Run the checking code, passing the remainder of the command line as
2719 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2720 it as the only set numerical variable. The authenticator may set $auth<n>
2721 and also set other numeric variables. The $auth<n> variables are preferred
2722 nowadays; the numerical variables remain for backwards compatibility.
2724 Afterwards, have a go at expanding the set_id string, even if
2725 authentication failed - for bad passwords it can be useful to log the
2726 userid. On success, require set_id to expand and exist, and put it in
2727 authenticated_id. Save this in permanent store, as the working store gets
2728 reset at HELO, RSET, etc. */
2730 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2732 expand_nlength[0] = 0; /* $0 contains nothing */
2734 c = (au->info->servercode)(au, smtp_cmd_data);
2735 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2736 expand_nmax = -1; /* Reset numeric variables */
2737 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2739 /* The value of authenticated_id is stored in the spool file and printed in
2740 log lines. It must not contain binary zeros or newline characters. In
2741 normal use, it never will, but when playing around or testing, this error
2742 can (did) happen. To guard against this, ensure that the id contains only
2743 printing characters. */
2745 if (set_id != NULL) set_id = string_printing(set_id);
2747 /* For the non-OK cases, set up additional logging data if set_id
2752 if (set_id != NULL && *set_id != 0)
2753 set_id = string_sprintf(" (set_id=%s)", set_id);
2757 /* Switch on the result */
2762 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2764 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2765 sender_host_authenticated = au->name;
2766 authentication_failed = FALSE;
2768 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2769 ((sender_host_address != NULL)? pnlocal : 0);
2770 s = ss = US"235 Authentication succeeded";
2771 authenticated_by = au;
2775 /* Authentication succeeded, but we failed to expand the set_id string.
2776 Treat this as a temporary error. */
2778 auth_defer_msg = expand_string_message;
2782 s = string_sprintf("435 Unable to authenticate at present%s",
2783 auth_defer_user_msg);
2784 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2785 set_id, auth_defer_msg);
2789 s = ss = US"501 Invalid base64 data";
2793 s = ss = US"501 Authentication cancelled";
2797 s = ss = US"553 Initial data not expected";
2801 s = US"535 Incorrect authentication data";
2802 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2806 s = US"435 Internal error";
2807 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2808 "check", set_id, c);
2812 smtp_printf("%s\r\n", s);
2814 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2815 au->name, host_and_ident(FALSE), ss);
2817 break; /* AUTH_CMD */
2819 /* The HELO/EHLO commands are permitted to appear in the middle of a
2820 session as well as at the beginning. They have the effect of a reset in
2821 addition to their other functions. Their absence at the start cannot be
2822 taken to be an error.
2826 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2827 or 502 failure replies MUST be returned as appropriate. The SMTP
2828 server MUST stay in the same state after transmitting these replies
2829 that it was in before the EHLO was received.
2831 Therefore, we do not do the reset until after checking the command for
2832 acceptability. This change was made for Exim release 4.11. Previously
2833 it did the reset first. */
2846 HELO_EHLO: /* Common code for HELO and EHLO */
2847 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2848 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2850 /* Reject the HELO if its argument was invalid or non-existent. A
2851 successful check causes the argument to be saved in malloc store. */
2853 if (!check_helo(smtp_cmd_data))
2855 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2857 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2858 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2859 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2860 string_printing(smtp_cmd_argument));
2862 if (++synprot_error_count > smtp_max_synprot_errors)
2864 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2865 "syntax or protocol errors (last command was \"%s\")",
2866 host_and_ident(FALSE), smtp_cmd_buffer);
2873 /* If sender_host_unknown is true, we have got here via the -bs interface,
2874 not called from inetd. Otherwise, we are running an IP connection and the
2875 host address will be set. If the helo name is the primary name of this
2876 host and we haven't done a reverse lookup, force one now. If helo_required
2877 is set, ensure that the HELO name matches the actual host. If helo_verify
2878 is set, do the same check, but softly. */
2880 if (!sender_host_unknown)
2882 BOOL old_helo_verified = helo_verified;
2883 uschar *p = smtp_cmd_data;
2885 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2888 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2889 because otherwise the log can be confusing. */
2891 if (sender_host_name == NULL &&
2892 (deliver_domain = sender_helo_name, /* set $domain */
2893 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2894 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2895 (void)host_name_lookup();
2897 /* Rebuild the fullhost info to include the HELO name (and the real name
2898 if it was looked up.) */
2900 host_build_sender_fullhost(); /* Rebuild */
2901 set_process_info("handling%s incoming connection from %s",
2902 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2904 /* Verify if configured. This doesn't give much security, but it does
2905 make some people happy to be able to do it. If helo_required is set,
2906 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2907 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2908 now obsolescent, since the verification can now be requested selectively
2911 helo_verified = helo_verify_failed = FALSE;
2912 if (helo_required || helo_verify)
2914 BOOL tempfail = !smtp_verify_helo();
2919 smtp_printf("%d %s argument does not match calling host\r\n",
2920 tempfail? 451 : 550, hello);
2921 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2922 tempfail? "temporarily " : "",
2923 hello, sender_helo_name, host_and_ident(FALSE));
2924 helo_verified = old_helo_verified;
2925 break; /* End of HELO/EHLO processing */
2927 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2928 "helo_try_verify_hosts\n", hello);
2933 #ifdef EXPERIMENTAL_SPF
2934 /* set up SPF context */
2935 spf_init(sender_helo_name, sender_host_address);
2938 /* Apply an ACL check if one is defined; afterwards, recheck
2939 synchronization in case the client started sending in a delay. */
2941 if (acl_smtp_helo != NULL)
2943 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2946 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2947 sender_helo_name = NULL;
2948 host_build_sender_fullhost(); /* Rebuild */
2951 else if (!check_sync()) goto SYNC_FAILURE;
2954 /* Generate an OK reply. The default string includes the ident if present,
2955 and also the IP address if present. Reflecting back the ident is intended
2956 as a deterrent to mail forgers. For maximum efficiency, and also because
2957 some broken systems expect each response to be in a single packet, arrange
2958 that the entire reply is sent in one write(). */
2960 auth_advertised = FALSE;
2961 pipelining_advertised = FALSE;
2963 tls_advertised = FALSE;
2966 smtp_code = US"250 "; /* Default response code plus space*/
2967 if (user_msg == NULL)
2969 s = string_sprintf("%.3s %s Hello %s%s%s",
2971 smtp_active_hostname,
2972 (sender_ident == NULL)? US"" : sender_ident,
2973 (sender_ident == NULL)? US"" : US" at ",
2974 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2979 if (sender_host_address != NULL)
2981 s = string_cat(s, &size, &ptr, US" [", 2);
2982 s = string_cat(s, &size, &ptr, sender_host_address,
2983 Ustrlen(sender_host_address));
2984 s = string_cat(s, &size, &ptr, US"]", 1);
2988 /* A user-supplied EHLO greeting may not contain more than one line. Note
2989 that the code returned by smtp_message_code() includes the terminating
2990 whitespace character. */
2996 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
2997 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
2998 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3000 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3001 "newlines: message truncated: %s", string_printing(s));
3008 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3010 /* If we received EHLO, we must create a multiline response which includes
3011 the functions supported. */
3017 /* I'm not entirely happy with this, as an MTA is supposed to check
3018 that it has enough room to accept a message of maximum size before
3019 it sends this. However, there seems little point in not sending it.
3020 The actual size check happens later at MAIL FROM time. By postponing it
3021 till then, VRFY and EXPN can be used after EHLO when space is short. */
3023 if (thismessage_size_limit > 0)
3025 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3026 thismessage_size_limit);
3027 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3031 s = string_cat(s, &size, &ptr, smtp_code, 3);
3032 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3035 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3036 clean; if it has an 8-bit character in its hand, it just sends it. It
3037 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3038 However, some users want this option simply in order to stop MUAs
3039 mangling messages that contain top-bit-set characters. It is therefore
3040 provided as an option. */
3042 if (accept_8bitmime)
3044 s = string_cat(s, &size, &ptr, smtp_code, 3);
3045 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3048 /* Advertise ETRN if there's an ACL checking whether a host is
3049 permitted to issue it; a check is made when any host actually tries. */
3051 if (acl_smtp_etrn != NULL)
3053 s = string_cat(s, &size, &ptr, smtp_code, 3);
3054 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3057 /* Advertise EXPN if there's an ACL checking whether a host is
3058 permitted to issue it; a check is made when any host actually tries. */
3060 if (acl_smtp_expn != NULL)
3062 s = string_cat(s, &size, &ptr, smtp_code, 3);
3063 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3066 /* Exim is quite happy with pipelining, so let the other end know that
3067 it is safe to use it, unless advertising is disabled. */
3069 if (pipelining_enable &&
3070 verify_check_host(&pipelining_advertise_hosts) == OK)
3072 s = string_cat(s, &size, &ptr, smtp_code, 3);
3073 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3074 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3075 pipelining_advertised = TRUE;
3078 /* If any server authentication mechanisms are configured, advertise
3079 them if the current host is in auth_advertise_hosts. The problem with
3080 advertising always is that some clients then require users to
3081 authenticate (and aren't configurable otherwise) even though it may not
3082 be necessary (e.g. if the host is in host_accept_relay).
3084 RFC 2222 states that SASL mechanism names contain only upper case
3085 letters, so output the names in upper case, though we actually recognize
3086 them in either case in the AUTH command. */
3090 if (verify_check_host(&auth_advertise_hosts) == OK)
3094 for (au = auths; au != NULL; au = au->next)
3096 if (au->server && (au->advertise_condition == NULL ||
3097 expand_check_condition(au->advertise_condition, au->name,
3098 US"authenticator")))
3103 s = string_cat(s, &size, &ptr, smtp_code, 3);
3104 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3106 auth_advertised = TRUE;
3109 s = string_cat(s, &size, &ptr, US" ", 1);
3110 s = string_cat(s, &size, &ptr, au->public_name,
3111 Ustrlen(au->public_name));
3112 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3113 au->advertised = TRUE;
3115 else au->advertised = FALSE;
3117 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3121 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3122 if it has been included in the binary, and the host matches
3123 tls_advertise_hosts. We must *not* advertise if we are already in a
3124 secure connection. */
3127 if (tls_active < 0 &&
3128 verify_check_host(&tls_advertise_hosts) != FAIL)
3130 s = string_cat(s, &size, &ptr, smtp_code, 3);
3131 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3132 tls_advertised = TRUE;
3136 /* Finish off the multiline reply with one that is always available. */
3138 s = string_cat(s, &size, &ptr, smtp_code, 3);
3139 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3142 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3148 if (tls_active >= 0) (void)tls_write(s, ptr); else
3151 (void)fwrite(s, 1, ptr, smtp_out);
3155 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3156 memmove(cr, cr + 1, (ptr--) - (cr - s));
3157 debug_printf("SMTP>> %s", s);
3161 /* Reset the protocol and the state, abandoning any previous message. */
3163 received_protocol = (esmtp?
3165 ((sender_host_authenticated != NULL)? pauthed : 0) +
3166 ((tls_active >= 0)? pcrpted : 0)]
3168 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
3170 ((sender_host_address != NULL)? pnlocal : 0);
3172 smtp_reset(reset_point);
3174 break; /* HELO/EHLO */
3177 /* The MAIL command requires an address as an operand. All we do
3178 here is to parse it for syntactic correctness. The form "<>" is
3179 a special case which converts into an empty string. The start/end
3180 pointers in the original are not used further for this address, as
3181 it is the canonical extracted address which is all that is kept. */
3185 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3186 was_rej_mail = TRUE; /* Reset if accepted */
3188 if (helo_required && !helo_seen)
3190 smtp_printf("503 HELO or EHLO required\r\n");
3191 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3192 "HELO/EHLO given", host_and_ident(FALSE));
3196 if (sender_address != NULL)
3198 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3199 US"sender already given");
3203 if (smtp_cmd_data[0] == 0)
3205 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3206 US"MAIL must have an address operand");
3210 /* Check to see if the limit for messages per connection would be
3211 exceeded by accepting further messages. */
3213 if (smtp_accept_max_per_connection > 0 &&
3214 smtp_mailcmd_count > smtp_accept_max_per_connection)
3216 smtp_printf("421 too many messages in this connection\r\n");
3217 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3218 "messages in one connection", host_and_ident(TRUE));
3222 /* Reset for start of message - even if this is going to fail, we
3223 obviously need to throw away any previous data. */
3225 smtp_reset(reset_point);
3227 sender_data = recipient_data = NULL;
3229 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3233 uschar *name, *value, *end;
3234 unsigned long int size;
3236 if (!extract_option(&name, &value)) break;
3238 /* Handle SIZE= by reading the value. We don't do the check till later,
3239 in order to be able to log the sender address on failure. */
3241 if (strcmpic(name, US"SIZE") == 0 &&
3242 ((size = Ustrtoul(value, &end, 10)), *end == 0))
3244 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3246 message_size = (int)size;
3249 /* If this session was initiated with EHLO and accept_8bitmime is set,
3250 Exim will have indicated that it supports the BODY=8BITMIME option. In
3251 fact, it does not support this according to the RFCs, in that it does not
3252 take any special action for forwarding messages containing 8-bit
3253 characters. That is why accept_8bitmime is not the default setting, but
3254 some sites want the action that is provided. We recognize both "8BITMIME"
3255 and "7BIT" as body types, but take no action. */
3257 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
3258 (strcmpic(value, US"8BITMIME") == 0 ||
3259 strcmpic(value, US"7BIT") == 0)) {}
3261 /* Handle the AUTH extension. If the value given is not "<>" and either
3262 the ACL says "yes" or there is no ACL but the sending host is
3263 authenticated, we set it up as the authenticated sender. However, if the
3264 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3265 the condition is met. The value of AUTH is an xtext, which means that +,
3266 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3269 else if (strcmpic(name, US"AUTH") == 0)
3271 if (Ustrcmp(value, "<>") != 0)
3276 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3278 /* Put back terminator overrides for error message */
3281 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3282 US"invalid data for AUTH");
3286 if (acl_smtp_mailauth == NULL)
3288 ignore_msg = US"client not authenticated";
3289 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3293 ignore_msg = US"rejected by ACL";
3294 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3295 &user_msg, &log_msg);
3301 if (authenticated_by == NULL ||
3302 authenticated_by->mail_auth_condition == NULL ||
3303 expand_check_condition(authenticated_by->mail_auth_condition,
3304 authenticated_by->name, US"authenticator"))
3305 break; /* Accept the AUTH */
3307 ignore_msg = US"server_mail_auth_condition failed";
3308 if (authenticated_id != NULL)
3309 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3310 ignore_msg, authenticated_id);
3315 authenticated_sender = NULL;
3316 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3317 value, host_and_ident(TRUE), ignore_msg);
3320 /* Should only get DEFER or ERROR here. Put back terminator
3321 overrides for error message */
3326 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3333 /* Unknown option. Stick back the terminator characters and break
3334 the loop. An error for a malformed address will occur. */
3344 /* If we have passed the threshold for rate limiting, apply the current
3345 delay, and update it for next time, provided this is a limited host. */
3347 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3348 verify_check_host(&smtp_ratelimit_hosts) == OK)
3350 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3351 smtp_delay_mail/1000.0);
3352 millisleep((int)smtp_delay_mail);
3353 smtp_delay_mail *= smtp_rlm_factor;
3354 if (smtp_delay_mail > (double)smtp_rlm_limit)
3355 smtp_delay_mail = (double)smtp_rlm_limit;
3358 /* Now extract the address, first applying any SMTP-time rewriting. The
3359 TRUE flag allows "<>" as a sender address. */
3361 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3362 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3363 global_rewrite_rules) : smtp_cmd_data;
3365 /* rfc821_domains = TRUE; << no longer needed */
3367 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3369 /* rfc821_domains = FALSE; << no longer needed */
3371 if (raw_sender == NULL)
3373 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3377 sender_address = raw_sender;
3379 /* If there is a configured size limit for mail, check that this message
3380 doesn't exceed it. The check is postponed to this point so that the sender
3383 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3385 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3386 log_write(L_size_reject,
3387 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3388 "message too big: size%s=%d max=%d",
3390 host_and_ident(TRUE),
3391 (message_size == INT_MAX)? ">" : "",
3393 thismessage_size_limit);
3394 sender_address = NULL;
3398 /* Check there is enough space on the disk unless configured not to.
3399 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3400 plus the current message - i.e. we accept the message only if it won't
3401 reduce the space below the threshold. Add 5000 to the size to allow for
3402 overheads such as the Received: line and storing of recipients, etc.
3403 By putting the check here, even when SIZE is not given, it allow VRFY
3404 and EXPN etc. to be used when space is short. */
3406 if (!receive_check_fs(
3407 (smtp_check_spool_space && message_size >= 0)?
3408 message_size + 5000 : 0))
3410 smtp_printf("452 Space shortage, please try later\r\n");
3411 sender_address = NULL;
3415 /* If sender_address is unqualified, reject it, unless this is a locally
3416 generated message, or the sending host or net is permitted to send
3417 unqualified addresses - typically local machines behaving as MUAs -
3418 in which case just qualify the address. The flag is set above at the start
3419 of the SMTP connection. */
3421 if (sender_domain == 0 && sender_address[0] != 0)
3423 if (allow_unqualified_sender)
3425 sender_domain = Ustrlen(sender_address) + 1;
3426 sender_address = rewrite_address_qualify(sender_address, FALSE);
3427 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3432 smtp_printf("501 %s: sender address must contain a domain\r\n",
3434 log_write(L_smtp_syntax_error,
3435 LOG_MAIN|LOG_REJECT,
3436 "unqualified sender rejected: <%s> %s%s",
3438 host_and_ident(TRUE),
3440 sender_address = NULL;
3445 /* Apply an ACL check if one is defined, before responding. Afterwards,
3446 when pipelining is not advertised, do another sync check in case the ACL
3447 delayed and the client started sending in the meantime. */
3449 if (acl_smtp_mail == NULL) rc = OK; else
3451 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3452 if (rc == OK && !pipelining_advertised && !check_sync())
3456 if (rc == OK || rc == DISCARD)
3458 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3459 else smtp_user_msg(US"250", user_msg);
3460 smtp_delay_rcpt = smtp_rlr_base;
3461 recipients_discarded = (rc == DISCARD);
3462 was_rej_mail = FALSE;
3466 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3467 sender_address = NULL;
3472 /* The RCPT command requires an address as an operand. There may be any
3473 number of RCPT commands, specifying multiple recipients. We build them all
3474 into a data structure. The start/end values given by parse_extract_address
3475 are not used, as we keep only the extracted address. */
3480 was_rcpt = rcpt_in_progress = TRUE;
3482 /* There must be a sender address; if the sender was rejected and
3483 pipelining was advertised, we assume the client was pipelining, and do not
3484 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3485 get the same treatment. */
3487 if (sender_address == NULL)
3489 if (pipelining_advertised && last_was_rej_mail)
3491 smtp_printf("503 sender not yet given\r\n");
3492 was_rej_mail = TRUE;
3496 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3497 US"sender not yet given");
3498 was_rcpt = FALSE; /* Not a valid RCPT */
3504 /* Check for an operand */
3506 if (smtp_cmd_data[0] == 0)
3508 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3509 US"RCPT must have an address operand");
3514 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3515 as a recipient address */
3517 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3518 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3519 global_rewrite_rules) : smtp_cmd_data;
3521 /* rfc821_domains = TRUE; << no longer needed */
3522 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3523 &recipient_domain, FALSE);
3524 /* rfc821_domains = FALSE; << no longer needed */
3526 if (recipient == NULL)
3528 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3533 /* If the recipient address is unqualified, reject it, unless this is a
3534 locally generated message. However, unqualified addresses are permitted
3535 from a configured list of hosts and nets - typically when behaving as
3536 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3537 really. The flag is set at the start of the SMTP connection.
3539 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3540 assumed this meant "reserved local part", but the revision of RFC 821 and
3541 friends now makes it absolutely clear that it means *mailbox*. Consequently
3542 we must always qualify this address, regardless. */
3544 if (recipient_domain == 0)
3546 if (allow_unqualified_recipient ||
3547 strcmpic(recipient, US"postmaster") == 0)
3549 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3551 recipient_domain = Ustrlen(recipient) + 1;
3552 recipient = rewrite_address_qualify(recipient, TRUE);
3557 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3559 log_write(L_smtp_syntax_error,
3560 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3561 "<%s> %s%s", recipient, host_and_ident(TRUE),
3567 /* Check maximum allowed */
3569 if (rcpt_count > recipients_max && recipients_max > 0)
3571 if (recipients_max_reject)
3574 smtp_printf("552 too many recipients\r\n");
3576 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3577 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3582 smtp_printf("452 too many recipients\r\n");
3584 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3585 "temporarily rejected: sender=<%s> %s", sender_address,
3586 host_and_ident(TRUE));
3593 /* If we have passed the threshold for rate limiting, apply the current
3594 delay, and update it for next time, provided this is a limited host. */
3596 if (rcpt_count > smtp_rlr_threshold &&
3597 verify_check_host(&smtp_ratelimit_hosts) == OK)
3599 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3600 smtp_delay_rcpt/1000.0);
3601 millisleep((int)smtp_delay_rcpt);
3602 smtp_delay_rcpt *= smtp_rlr_factor;
3603 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3604 smtp_delay_rcpt = (double)smtp_rlr_limit;
3607 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3608 for them. Otherwise, check the access control list for this recipient. As
3609 there may be a delay in this, re-check for a synchronization error
3610 afterwards, unless pipelining was advertised. */
3612 if (recipients_discarded) rc = DISCARD; else
3614 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
3616 if (rc == OK && !pipelining_advertised && !check_sync())
3620 /* The ACL was happy */
3624 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3625 else smtp_user_msg(US"250", user_msg);
3626 receive_add_recipient(recipient, -1);
3629 /* The recipient was discarded */
3631 else if (rc == DISCARD)
3633 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3634 else smtp_user_msg(US"250", user_msg);
3637 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3638 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3639 (sender_address_unrewritten != NULL)?
3640 sender_address_unrewritten : sender_address,
3641 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3642 (log_msg == NULL)? US"" : US": ",
3643 (log_msg == NULL)? US"" : log_msg);
3646 /* Either the ACL failed the address, or it was deferred. */
3650 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3651 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3656 /* The DATA command is legal only if it follows successful MAIL FROM
3657 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3658 not counted as a protocol error if it follows RCPT (which must have been
3659 rejected if there are no recipients.) This function is complete when a
3660 valid DATA command is encountered.
3662 Note concerning the code used: RFC 2821 says this:
3664 - If there was no MAIL, or no RCPT, command, or all such commands
3665 were rejected, the server MAY return a "command out of sequence"
3666 (503) or "no valid recipients" (554) reply in response to the
3669 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3670 because it is the same whether pipelining is in use or not.
3672 If all the RCPT commands that precede DATA provoked the same error message
3673 (often indicating some kind of system error), it is helpful to include it
3674 with the DATA rejection (an idea suggested by Tony Finch). */
3678 if (!discarded && recipients_count <= 0)
3680 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
3682 uschar *code = US"503";
3683 int len = Ustrlen(rcpt_smtp_response);
3684 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
3686 /* Responses from smtp_printf() will have \r\n on the end */
3687 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
3688 rcpt_smtp_response[len-2] = 0;
3689 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
3691 if (pipelining_advertised && last_was_rcpt)
3692 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
3694 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3695 US"valid RCPT command must precede DATA");
3699 if (toomany && recipients_max_reject)
3701 sender_address = NULL; /* This will allow a new MAIL without RSET */
3702 sender_address_unrewritten = NULL;
3703 smtp_printf("554 Too many recipients\r\n");
3707 /* If there is an ACL, re-check the synchronization afterwards, since the
3708 ACL may have delayed. */
3710 if (acl_smtp_predata == NULL) rc = OK; else
3712 enable_dollar_recipients = TRUE;
3713 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3715 enable_dollar_recipients = FALSE;
3716 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
3721 if (user_msg == NULL)
3722 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3723 else smtp_user_msg(US"354", user_msg);
3725 message_ended = END_NOTENDED; /* Indicate in middle of data */
3728 /* Either the ACL failed the address, or it was deferred. */
3731 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3737 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3739 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3745 /* rfc821_domains = TRUE; << no longer needed */
3746 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
3747 &recipient_domain, FALSE);
3748 /* rfc821_domains = FALSE; << no longer needed */
3750 if (address == NULL)
3751 s = string_sprintf("501 %s", errmess);
3754 address_item *addr = deliver_make_addr(address, FALSE);
3755 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3756 -1, -1, NULL, NULL, NULL))
3759 s = string_sprintf("250 <%s> is deliverable", address);
3763 s = (addr->user_message != NULL)?
3764 string_sprintf("451 <%s> %s", address, addr->user_message) :
3765 string_sprintf("451 Cannot resolve <%s> at this time", address);
3769 s = (addr->user_message != NULL)?
3770 string_sprintf("550 <%s> %s", address, addr->user_message) :
3771 string_sprintf("550 <%s> is not deliverable", address);
3772 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3773 smtp_cmd_argument, host_and_ident(TRUE));
3778 smtp_printf("%s\r\n", s);
3785 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3787 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3790 BOOL save_log_testing_mode = log_testing_mode;
3791 address_test_mode = log_testing_mode = TRUE;
3792 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
3793 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3795 address_test_mode = FALSE;
3796 log_testing_mode = save_log_testing_mode; /* true for -bh */
3805 if (!tls_advertised)
3807 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3808 US"STARTTLS command used when not advertised");
3812 /* Apply an ACL check if one is defined */
3814 if (acl_smtp_starttls != NULL)
3816 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3820 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3825 /* RFC 2487 is not clear on when this command may be sent, though it
3826 does state that all information previously obtained from the client
3827 must be discarded if a TLS session is started. It seems reasonble to
3828 do an implied RSET when STARTTLS is received. */
3830 incomplete_transaction_log(US"STARTTLS");
3831 smtp_reset(reset_point);
3833 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3835 /* Attempt to start up a TLS session, and if successful, discard all
3836 knowledge that was obtained previously. At least, that's what the RFC says,
3837 and that's what happens by default. However, in order to work round YAEB,
3838 there is an option to remember the esmtp state. Sigh.
3840 We must allow for an extra EHLO command and an extra AUTH command after
3841 STARTTLS that don't add to the nonmail command count. */
3843 if ((rc = tls_server_start(tls_require_ciphers, gnutls_require_mac,
3844 gnutls_require_kx, gnutls_require_proto)) == OK)
3846 if (!tls_remember_esmtp)
3847 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3848 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3849 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3850 if (sender_helo_name != NULL)
3852 store_free(sender_helo_name);
3853 sender_helo_name = NULL;
3854 host_build_sender_fullhost(); /* Rebuild */
3855 set_process_info("handling incoming TLS connection from %s",
3856 host_and_ident(FALSE));
3858 received_protocol = (esmtp?
3859 protocols[pextend + pcrpted +
3860 ((sender_host_authenticated != NULL)? pauthed : 0)]
3862 protocols[pnormal + pcrpted])
3864 ((sender_host_address != NULL)? pnlocal : 0);
3866 sender_host_authenticated = NULL;
3867 authenticated_id = NULL;
3868 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3869 DEBUG(D_tls) debug_printf("TLS active\n");
3870 break; /* Successful STARTTLS */
3873 /* Some local configuration problem was discovered before actually trying
3874 to do a TLS handshake; give a temporary error. */
3876 else if (rc == DEFER)
3878 smtp_printf("454 TLS currently unavailable\r\n");
3882 /* Hard failure. Reject everything except QUIT or closed connection. One
3883 cause for failure is a nested STARTTLS, in which case tls_active remains
3884 set, but we must still reject all incoming commands. */
3886 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3889 switch(smtp_read_command(FALSE))
3892 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3893 smtp_get_connection_info());
3894 smtp_notquit_exit(US"tls-failed", NULL, NULL);
3898 /* It is perhaps arguable as to which exit ACL should be called here,
3899 but as it is probably a situtation that almost never arises, it
3900 probably doesn't matter. We choose to call the real QUIT ACL, which in
3901 some sense is perhaps "right". */
3905 if (acl_smtp_quit != NULL)
3907 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
3910 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3913 if (user_msg == NULL)
3914 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3916 smtp_respond(US"221", 3, TRUE, user_msg);
3917 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3918 smtp_get_connection_info());
3923 smtp_printf("554 Security failure\r\n");
3932 /* The ACL for QUIT is provided for gathering statistical information or
3933 similar; it does not affect the response code, but it can supply a custom
3938 incomplete_transaction_log(US"QUIT");
3939 if (acl_smtp_quit != NULL)
3941 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
3943 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3946 if (user_msg == NULL)
3947 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3949 smtp_respond(US"221", 3, TRUE, user_msg);
3956 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3957 smtp_get_connection_info());
3963 incomplete_transaction_log(US"RSET");
3964 smtp_reset(reset_point);
3966 smtp_printf("250 Reset OK\r\n");
3967 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3973 smtp_printf("250 OK\r\n");
3977 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
3978 used, a check will be done for permitted hosts. Show STARTTLS only if not
3979 already in a TLS session and if it would be advertised in the EHLO
3984 smtp_printf("214-Commands supported:\r\n");
3988 Ustrcat(buffer, " AUTH");
3990 if (tls_active < 0 &&
3991 verify_check_host(&tls_advertise_hosts) != FAIL)
3992 Ustrcat(buffer, " STARTTLS");
3994 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3995 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3996 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3997 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3998 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3999 smtp_printf("214%s\r\n", buffer);
4005 incomplete_transaction_log(US"connection lost");
4006 smtp_notquit_exit(US"connection-lost", US"421",
4007 US"%s lost input connection", smtp_active_hostname);
4009 /* Don't log by default unless in the middle of a message, as some mailers
4010 just drop the call rather than sending QUIT, and it clutters up the logs.
4013 if (sender_address != NULL || recipients_count > 0)
4014 log_write(L_lost_incoming_connection,
4016 "unexpected %s while reading SMTP command from %s%s",
4017 sender_host_unknown? "EOF" : "disconnection",
4018 host_and_ident(FALSE), smtp_read_error);
4020 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4021 smtp_get_connection_info(), smtp_read_error);
4029 if (sender_address != NULL)
4031 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4032 US"ETRN is not permitted inside a transaction");
4036 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4037 host_and_ident(FALSE));
4039 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4042 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4046 /* Compute the serialization key for this command. */
4048 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4050 /* If a command has been specified for running as a result of ETRN, we
4051 permit any argument to ETRN. If not, only the # standard form is permitted,
4052 since that is strictly the only kind of ETRN that can be implemented
4053 according to the RFC. */
4055 if (smtp_etrn_command != NULL)
4059 etrn_command = smtp_etrn_command;
4060 deliver_domain = smtp_cmd_data;
4061 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4062 US"ETRN processing", &error);
4063 deliver_domain = NULL;
4066 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4068 smtp_printf("458 Internal failure\r\n");
4073 /* Else set up to call Exim with the -R option. */
4077 if (*smtp_cmd_data++ != '#')
4079 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4080 US"argument must begin with #");
4083 etrn_command = US"exim -R";
4084 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4088 /* If we are host-testing, don't actually do anything. */
4094 debug_printf("ETRN command is: %s\n", etrn_command);
4095 debug_printf("ETRN command execution skipped\n");
4097 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4098 else smtp_user_msg(US"250", user_msg);
4103 /* If ETRN queue runs are to be serialized, check the database to
4104 ensure one isn't already running. */
4106 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4108 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4112 /* Fork a child process and run the command. We don't want to have to
4113 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4114 forking. It should be set that way anyway for external incoming SMTP,
4115 but we save and restore to be tidy. If serialization is required, we
4116 actually run the command in yet another process, so we can wait for it
4117 to complete and then remove the serialization lock. */
4119 oldsignal = signal(SIGCHLD, SIG_IGN);
4121 if ((pid = fork()) == 0)
4123 smtp_input = FALSE; /* This process is not associated with the */
4124 (void)fclose(smtp_in); /* SMTP call any more. */
4125 (void)fclose(smtp_out);
4127 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
4129 /* If not serializing, do the exec right away. Otherwise, fork down
4130 into another process. */
4132 if (!smtp_etrn_serialize || (pid = fork()) == 0)
4134 DEBUG(D_exec) debug_print_argv(argv);
4135 exim_nullstd(); /* Ensure std{in,out,err} exist */
4136 execv(CS argv[0], (char *const *)argv);
4137 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
4138 etrn_command, strerror(errno));
4139 _exit(EXIT_FAILURE); /* paranoia */
4142 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4143 is, we are in the first subprocess, after forking again. All we can do
4144 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4145 complete, before removing the serialization. */
4148 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4149 "failed: %s", strerror(errno));
4153 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4155 (void)wait(&status);
4156 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4160 enq_end(etrn_serialize_key);
4161 _exit(EXIT_SUCCESS);
4164 /* Back in the top level SMTP process. Check that we started a subprocess
4165 and restore the signal state. */
4169 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4171 smtp_printf("458 Unable to fork process\r\n");
4172 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4176 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4177 else smtp_user_msg(US"250", user_msg);
4180 signal(SIGCHLD, oldsignal);
4185 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4186 US"unexpected argument data");
4190 /* This currently happens only for NULLs, but could be extended. */
4193 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
4194 US"NULL character(s) present (shown as '?')");
4195 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
4201 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
4202 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
4203 c = smtp_inend - smtp_inptr;
4204 if (c > 150) c = 150;
4206 incomplete_transaction_log(US"sync failure");
4207 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
4208 "(next input sent too soon: pipelining was%s advertised): "
4209 "rejected \"%s\" %s next input=\"%s\"",
4210 pipelining_advertised? "" : " not",
4211 smtp_cmd_buffer, host_and_ident(TRUE),
4212 string_printing(smtp_inptr));
4213 smtp_notquit_exit(US"synchronization-error", US"554",
4214 US"SMTP synchronization error");
4215 done = 1; /* Pretend eof - drops connection */
4219 case TOO_MANY_NONMAIL_CMD:
4220 s = smtp_cmd_buffer;
4221 while (*s != 0 && !isspace(*s)) s++;
4222 incomplete_transaction_log(US"too many non-mail commands");
4223 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4224 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
4225 s - smtp_cmd_buffer, smtp_cmd_buffer);
4226 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
4227 done = 1; /* Pretend eof - drops connection */
4232 if (unknown_command_count++ >= smtp_max_unknown_commands)
4234 log_write(L_smtp_syntax_error, LOG_MAIN,
4235 "SMTP syntax error in \"%s\" %s %s",
4236 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
4237 US"unrecognized command");
4238 incomplete_transaction_log(US"unrecognized command");
4239 smtp_notquit_exit(US"bad-commands", US"500",
4240 US"Too many unrecognized commands");
4242 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4243 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
4247 done = synprot_error(L_smtp_syntax_error, 500, NULL,
4248 US"unrecognized command");
4252 /* This label is used by goto's inside loops that want to break out to
4253 the end of the command-processing loop. */
4256 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
4257 last_was_rcpt = was_rcpt; /* protocol error handling */
4261 return done - 2; /* Convert yield values */
4264 /* End of smtp_in.c */
git://git.exim.org / users / jgh / exim.git / blob