1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.65 2009/10/15 08:06:23 tom Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2007 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. */
42 #define smtp_cmd_buffer_size 2048
44 /* Size of buffer for reading SMTP incoming packets */
46 #define in_buffer_size 8192
48 /* Structure for SMTP command list */
55 short int is_mail_cmd;
58 /* Codes for identifying commands. We order them so that those that come first
59 are those for which synchronization is always required. Checking this can help
63 /* These commands are required to be synchronized, i.e. to be the last in a
64 block of commands when pipelining. */
66 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
67 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
68 ETRN_CMD, /* This by analogy with TURN from the RFC */
69 STARTTLS_CMD, /* Required by the STARTTLS RFC */
71 /* This is a dummy to identify the non-sync commands when pipelining */
73 NON_SYNC_CMD_PIPELINING,
75 /* These commands need not be synchronized when pipelining */
77 MAIL_CMD, RCPT_CMD, RSET_CMD,
79 /* This is a dummy to identify the non-sync commands when not pipelining */
81 NON_SYNC_CMD_NON_PIPELINING,
83 /* I have been unable to find a statement about the use of pipelining
84 with AUTH, so to be on the safe side it is here, though I kind of feel
85 it should be up there with the synchronized commands. */
89 /* I'm not sure about these, but I don't think they matter. */
93 /* These are specials that don't correspond to actual commands */
95 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
96 TOO_MANY_NONMAIL_CMD };
99 /* This is a convenience macro for adding the identity of an SMTP command
100 to the circular buffer that holds a list of the last n received. */
103 smtp_connection_had[smtp_ch_index++] = n; \
104 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
107 /*************************************************
108 * Local static variables *
109 *************************************************/
111 static auth_instance *authenticated_by;
112 static BOOL auth_advertised;
114 static BOOL tls_advertised;
117 static BOOL helo_required = FALSE;
118 static BOOL helo_verify = FALSE;
119 static BOOL helo_seen;
120 static BOOL helo_accept_junk;
121 static BOOL count_nonmail;
122 static BOOL pipelining_advertised;
123 static BOOL rcpt_smtp_response_same;
124 static BOOL rcpt_in_progress;
125 static int nonmail_command_count;
126 static BOOL smtp_exit_function_called = 0;
127 static int synprot_error_count;
128 static int unknown_command_count;
129 static int sync_cmd_limit;
130 static int smtp_write_error = 0;
132 static uschar *rcpt_smtp_response;
133 static uschar *smtp_data_buffer;
134 static uschar *smtp_cmd_data;
136 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
137 final fields of all except AUTH are forced TRUE at the start of a new message
138 setup, to allow one of each between messages that is not counted as a nonmail
139 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
140 allow a new EHLO after starting up TLS.
142 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
143 counted. However, the flag is changed when AUTH is received, so that multiple
144 failing AUTHs will eventually hit the limit. After a successful AUTH, another
145 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
146 forced TRUE, to allow for the re-authentication that can happen at that point.
148 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
149 count of non-mail commands and possibly provoke an error. */
151 static smtp_cmd_list cmd_list[] = {
152 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
153 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
154 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
155 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
157 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
160 /* If you change anything above here, also fix the definitions below. */
162 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
163 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
164 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
165 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
166 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
167 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
168 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
169 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
170 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
173 static smtp_cmd_list *cmd_list_end =
174 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
176 #define CMD_LIST_RSET 0
177 #define CMD_LIST_HELO 1
178 #define CMD_LIST_EHLO 2
179 #define CMD_LIST_AUTH 3
180 #define CMD_LIST_STARTTLS 4
182 /* This list of names is used for performing the smtp_no_mail logging action.
183 It must be kept in step with the SCH_xxx enumerations. */
185 static uschar *smtp_names[] =
187 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
188 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
191 static uschar *protocols[] = {
192 US"local-smtp", /* HELO */
193 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
194 US"local-esmtp", /* EHLO */
195 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
196 US"local-esmtpa", /* EHLO->AUTH */
197 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
202 #define pcrpted 1 /* added to pextend or pnormal */
203 #define pauthed 2 /* added to pextend */
204 #define pnlocal 6 /* offset to remove "local" */
206 /* When reading SMTP from a remote host, we have to use our own versions of the
207 C input-reading functions, in order to be able to flush the SMTP output only
208 when about to read more data from the socket. This is the only way to get
209 optimal performance when the client is using pipelining. Flushing for every
210 command causes a separate packet and reply packet each time; saving all the
211 responses up (when pipelining) combines them into one packet and one response.
213 For simplicity, these functions are used for *all* SMTP input, not only when
214 receiving over a socket. However, after setting up a secure socket (SSL), input
215 is read via the OpenSSL library, and another set of functions is used instead
218 These functions are set in the receive_getc etc. variables and called with the
219 same interface as the C functions. However, since there can only ever be
220 one incoming SMTP call, we just use a single buffer and flags. There is no need
221 to implement a complicated private FILE-like structure.*/
223 static uschar *smtp_inbuffer;
224 static uschar *smtp_inptr;
225 static uschar *smtp_inend;
226 static int smtp_had_eof;
227 static int smtp_had_error;
230 /*************************************************
231 * SMTP version of getc() *
232 *************************************************/
234 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
235 it flushes the output, and refills the buffer, with a timeout. The signal
236 handler is set appropriately by the calling function. This function is not used
237 after a connection has negotated itself into an TLS/SSL state.
240 Returns: the next character or EOF
246 if (smtp_inptr >= smtp_inend)
250 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
251 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
256 /* Must put the error text in fixed store, because this might be during
257 header reading, where it releases unused store above the header. */
260 smtp_had_error = save_errno;
261 smtp_read_error = string_copy_malloc(
262 string_sprintf(" (error: %s)", strerror(save_errno)));
264 else smtp_had_eof = 1;
268 dkim_exim_verify_feed(smtp_inbuffer, rc);
270 smtp_inend = smtp_inbuffer + rc;
271 smtp_inptr = smtp_inbuffer;
273 return *smtp_inptr++;
278 /*************************************************
279 * SMTP version of ungetc() *
280 *************************************************/
282 /* Puts a character back in the input buffer. Only ever
288 Returns: the character
294 *(--smtp_inptr) = ch;
301 /*************************************************
302 * SMTP version of feof() *
303 *************************************************/
305 /* Tests for a previous EOF
308 Returns: non-zero if the eof flag is set
320 /*************************************************
321 * SMTP version of ferror() *
322 *************************************************/
324 /* Tests for a previous read error, and returns with errno
325 restored to what it was when the error was detected.
328 Returns: non-zero if the error flag is set
334 errno = smtp_had_error;
335 return smtp_had_error;
340 /*************************************************
341 * Test for characters in the SMTP buffer *
342 *************************************************/
344 /* Used at the end of a message
353 return smtp_inptr < smtp_inend;
358 /*************************************************
359 * Write formatted string to SMTP channel *
360 *************************************************/
362 /* This is a separate function so that we don't have to repeat everything for
363 TLS support or debugging. It is global so that the daemon and the
364 authentication functions can use it. It does not return any error indication,
365 because major problems such as dropped connections won't show up till an output
366 flush for non-TLS connections. The smtp_fflush() function is available for
367 checking that: for convenience, TLS output errors are remembered here so that
368 they are also picked up later by smtp_fflush().
372 ... optional arguments
378 smtp_printf(char *format, ...)
382 va_start(ap, format);
383 smtp_vprintf(format, ap);
387 /* This is split off so that verify.c:respond_printf() can, in effect, call
388 smtp_printf(), bearing in mind that in C a vararg function can't directly
389 call another vararg function, only a function which accepts a va_list.
391 Note also that repeated calls to va_start()/va_end() pairs is claimed to be
392 non-portable; meanwhile, va_copy() is also non-portable in that it's C99, so
393 we end up needing OS support to define it for us. */
396 smtp_vprintf(char *format, va_list ap)
404 (void) string_vformat(big_buffer, big_buffer_size, format, ap_d);
405 end = big_buffer + Ustrlen(big_buffer);
406 while ((cr = Ustrchr(big_buffer, '\r')) != NULL) /* lose CRs */
407 memmove(cr, cr + 1, (end--) - cr);
408 debug_printf("SMTP>> %s", big_buffer);
411 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
413 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
414 smtp_closedown(US"Unexpected error");
415 exim_exit(EXIT_FAILURE);
418 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
419 have had the same. Note: this code is also present in smtp_respond(). It would
420 be tidier to have it only in one place, but when it was added, it was easier to
421 do it that way, so as not to have to mess with the code for the RCPT command,
422 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
424 if (rcpt_in_progress)
426 if (rcpt_smtp_response == NULL)
427 rcpt_smtp_response = string_copy(big_buffer);
428 else if (rcpt_smtp_response_same &&
429 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
430 rcpt_smtp_response_same = FALSE;
431 rcpt_in_progress = FALSE;
434 /* Now write the string */
439 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
444 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
449 /*************************************************
450 * Flush SMTP out and check for error *
451 *************************************************/
453 /* This function isn't currently used within Exim (it detects errors when it
454 tries to read the next SMTP input), but is available for use in local_scan().
455 For non-TLS connections, it flushes the output and checks for errors. For
456 TLS-connections, it checks for a previously-detected TLS write error.
459 Returns: 0 for no error; -1 after an error
465 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
466 return smtp_write_error;
471 /*************************************************
472 * SMTP command read timeout *
473 *************************************************/
475 /* Signal handler for timing out incoming SMTP commands. This attempts to
478 Argument: signal number (SIGALRM)
483 command_timeout_handler(int sig)
485 sig = sig; /* Keep picky compilers happy */
486 log_write(L_lost_incoming_connection,
487 LOG_MAIN, "SMTP command timeout on%s connection from %s",
488 (tls_active >= 0)? " TLS" : "",
489 host_and_ident(FALSE));
490 if (smtp_batched_input)
491 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
492 smtp_notquit_exit(US"command-timeout", US"421",
493 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
494 exim_exit(EXIT_FAILURE);
499 /*************************************************
501 *************************************************/
503 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
505 Argument: signal number (SIGTERM)
510 command_sigterm_handler(int sig)
512 sig = sig; /* Keep picky compilers happy */
513 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
514 if (smtp_batched_input)
515 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
516 smtp_notquit_exit(US"signal-exit", US"421",
517 US"%s: Service not available - closing connection", smtp_active_hostname);
518 exim_exit(EXIT_FAILURE);
524 /*************************************************
525 * Read one command line *
526 *************************************************/
528 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
529 There are sites that don't do this, and in any case internal SMTP probably
530 should check only for LF. Consequently, we check here for LF only. The line
531 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
532 an unknown command. The command is read into the global smtp_cmd_buffer so that
533 it is available via $smtp_command.
535 The character reading routine sets up a timeout for each block actually read
536 from the input (which may contain more than one command). We set up a special
537 signal handler that closes down the session on a timeout. Control does not
541 check_sync if TRUE, check synchronization rules if global option is TRUE
543 Returns: a code identifying the command (enumerated above)
547 smtp_read_command(BOOL check_sync)
552 BOOL hadnull = FALSE;
554 os_non_restarting_signal(SIGALRM, command_timeout_handler);
556 while ((c = (receive_getc)()) != '\n' && c != EOF)
558 if (ptr >= smtp_cmd_buffer_size)
560 os_non_restarting_signal(SIGALRM, sigalrm_handler);
568 smtp_cmd_buffer[ptr++] = c;
571 receive_linecount++; /* For BSMTP errors */
572 os_non_restarting_signal(SIGALRM, sigalrm_handler);
574 /* If hit end of file, return pseudo EOF command. Whether we have a
575 part-line already read doesn't matter, since this is an error state. */
577 if (c == EOF) return EOF_CMD;
579 /* Remove any CR and white space at the end of the line, and terminate the
582 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
583 smtp_cmd_buffer[ptr] = 0;
585 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
587 /* NULLs are not allowed in SMTP commands */
589 if (hadnull) return BADCHAR_CMD;
591 /* Scan command list and return identity, having set the data pointer
592 to the start of the actual data characters. Check for SMTP synchronization
595 for (p = cmd_list; p < cmd_list_end; p++)
597 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
598 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
599 smtp_cmd_buffer[p->len] == 0 ||
600 smtp_cmd_buffer[p->len] == ' '))
602 if (smtp_inptr < smtp_inend && /* Outstanding input */
603 p->cmd < sync_cmd_limit && /* Command should sync */
604 check_sync && /* Local flag set */
605 smtp_enforce_sync && /* Global flag set */
606 sender_host_address != NULL && /* Not local input */
607 !sender_host_notsocket) /* Really is a socket */
610 /* The variables $smtp_command and $smtp_command_argument point into the
611 unmodified input buffer. A copy of the latter is taken for actual
612 processing, so that it can be chopped up into separate parts if necessary,
613 for example, when processing a MAIL command options such as SIZE that can
614 follow the sender address. */
616 smtp_cmd_argument = smtp_cmd_buffer + p->len;
617 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
618 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
619 smtp_cmd_data = smtp_data_buffer;
621 /* Count non-mail commands from those hosts that are controlled in this
622 way. The default is all hosts. We don't waste effort checking the list
623 until we get a non-mail command, but then cache the result to save checking
624 again. If there's a DEFER while checking the host, assume it's in the list.
626 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
627 start of each incoming message by fiddling with the value in the table. */
631 if (count_nonmail == TRUE_UNSET) count_nonmail =
632 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
633 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
634 return TOO_MANY_NONMAIL_CMD;
637 /* If there is data for a command that does not expect it, generate the
640 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
644 /* Enforce synchronization for unknown commands */
646 if (smtp_inptr < smtp_inend && /* Outstanding input */
647 check_sync && /* Local flag set */
648 smtp_enforce_sync && /* Global flag set */
649 sender_host_address != NULL && /* Not local input */
650 !sender_host_notsocket) /* Really is a socket */
658 /*************************************************
659 * Recheck synchronization *
660 *************************************************/
662 /* Synchronization checks can never be perfect because a packet may be on its
663 way but not arrived when the check is done. Such checks can in any case only be
664 done when TLS is not in use. Normally, the checks happen when commands are
665 read: Exim ensures that there is no more input in the input buffer. In normal
666 cases, the response to the command will be fast, and there is no further check.
668 However, for some commands an ACL is run, and that can include delays. In those
669 cases, it is useful to do another check on the input just before sending the
670 response. This also applies at the start of a connection. This function does
671 that check by means of the select() function, as long as the facility is not
672 disabled or inappropriate. A failure of select() is ignored.
674 When there is unwanted input, we read it so that it appears in the log of the
678 Returns: TRUE if all is well; FALSE if there is input pending
686 struct timeval tzero;
688 if (!smtp_enforce_sync || sender_host_address == NULL ||
689 sender_host_notsocket || tls_active >= 0)
692 fd = fileno(smtp_in);
697 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
699 if (rc <= 0) return TRUE; /* Not ready to read */
701 if (rc < 0) return TRUE; /* End of file or error */
704 rc = smtp_inend - smtp_inptr;
705 if (rc > 150) rc = 150;
712 /*************************************************
713 * Forced closedown of call *
714 *************************************************/
716 /* This function is called from log.c when Exim is dying because of a serious
717 disaster, and also from some other places. If an incoming non-batched SMTP
718 channel is open, it swallows the rest of the incoming message if in the DATA
719 phase, sends the reply string, and gives an error to all subsequent commands
720 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
724 message SMTP reply string to send, excluding the code
730 smtp_closedown(uschar *message)
732 if (smtp_in == NULL || smtp_batched_input) return;
733 receive_swallow_smtp();
734 smtp_printf("421 %s\r\n", message);
738 switch(smtp_read_command(FALSE))
744 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
749 smtp_printf("250 Reset OK\r\n");
753 smtp_printf("421 %s\r\n", message);
762 /*************************************************
763 * Set up connection info for logging *
764 *************************************************/
766 /* This function is called when logging information about an SMTP connection.
767 It sets up appropriate source information, depending on the type of connection.
768 If sender_fullhost is NULL, we are at a very early stage of the connection;
769 just use the IP address.
772 Returns: a string describing the connection
776 smtp_get_connection_info(void)
778 uschar *hostname = (sender_fullhost == NULL)?
779 sender_host_address : sender_fullhost;
782 return string_sprintf("SMTP connection from %s", hostname);
784 if (sender_host_unknown || sender_host_notsocket)
785 return string_sprintf("SMTP connection from %s", sender_ident);
788 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
790 if ((log_extra_selector & LX_incoming_interface) != 0 &&
791 interface_address != NULL)
792 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
793 interface_address, interface_port);
795 return string_sprintf("SMTP connection from %s", hostname);
800 /*************************************************
801 * Log lack of MAIL if so configured *
802 *************************************************/
804 /* This function is called when an SMTP session ends. If the log selector
805 smtp_no_mail is set, write a log line giving some details of what has happened
813 smtp_log_no_mail(void)
818 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
824 if (sender_host_authenticated != NULL)
826 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
827 if (authenticated_id != NULL)
828 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
832 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_cipher != NULL)
833 s = string_append(s, &size, &ptr, 2, US" X=", tls_cipher);
834 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
836 s = string_append(s, &size, &ptr, 2, US" CV=",
837 tls_certificate_verified? "yes":"no");
838 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_peerdn != NULL)
839 s = string_append(s, &size, &ptr, 3, US" DN=\"",
840 string_printing(tls_peerdn), US"\"");
843 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
844 US" C=..." : US" C=";
845 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
847 if (smtp_connection_had[i] != SCH_NONE)
849 s = string_append(s, &size, &ptr, 2, sep,
850 smtp_names[smtp_connection_had[i]]);
855 for (i = 0; i < smtp_ch_index; i++)
857 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
861 if (s != NULL) s[ptr] = 0; else s = US"";
862 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
863 host_and_ident(FALSE),
864 readconf_printtime(time(NULL) - smtp_connection_start), s);
869 /*************************************************
870 * Check HELO line and set sender_helo_name *
871 *************************************************/
873 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
874 the domain name of the sending host, or an ip literal in square brackets. The
875 arrgument is placed in sender_helo_name, which is in malloc store, because it
876 must persist over multiple incoming messages. If helo_accept_junk is set, this
877 host is permitted to send any old junk (needed for some broken hosts).
878 Otherwise, helo_allow_chars can be used for rogue characters in general
879 (typically people want to let in underscores).
882 s the data portion of the line (already past any white space)
884 Returns: TRUE or FALSE
888 check_helo(uschar *s)
891 uschar *end = s + Ustrlen(s);
892 BOOL yield = helo_accept_junk;
894 /* Discard any previous helo name */
896 if (sender_helo_name != NULL)
898 store_free(sender_helo_name);
899 sender_helo_name = NULL;
902 /* Skip tests if junk is permitted. */
906 /* Allow the new standard form for IPv6 address literals, namely,
907 [IPv6:....], and because someone is bound to use it, allow an equivalent
908 IPv4 form. Allow plain addresses as well. */
915 if (strncmpic(s, US"[IPv6:", 6) == 0)
916 yield = (string_is_ip_address(s+6, NULL) == 6);
917 else if (strncmpic(s, US"[IPv4:", 6) == 0)
918 yield = (string_is_ip_address(s+6, NULL) == 4);
920 yield = (string_is_ip_address(s+1, NULL) != 0);
925 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
926 that have been configured (usually underscore - sigh). */
933 if (!isalnum(*s) && *s != '.' && *s != '-' &&
934 Ustrchr(helo_allow_chars, *s) == NULL)
944 /* Save argument if OK */
946 if (yield) sender_helo_name = string_copy_malloc(start);
954 /*************************************************
955 * Extract SMTP command option *
956 *************************************************/
958 /* This function picks the next option setting off the end of smtp_cmd_data. It
959 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
960 things that can appear there.
963 name point this at the name
964 value point this at the data string
966 Returns: TRUE if found an option
970 extract_option(uschar **name, uschar **value)
973 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
974 while (isspace(*v)) v--;
977 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
978 if (*v != '=') return FALSE;
981 while(isalpha(n[-1])) n--;
983 if (n[-1] != ' ') return FALSE;
996 /*************************************************
997 * Reset for new message *
998 *************************************************/
1000 /* This function is called whenever the SMTP session is reset from
1001 within either of the setup functions.
1003 Argument: the stacking pool storage reset point
1008 smtp_reset(void *reset_point)
1010 store_reset(reset_point);
1011 recipients_list = NULL;
1012 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1013 raw_recipients_count = recipients_count = recipients_list_max = 0;
1014 message_linecount = 0;
1016 acl_added_headers = NULL;
1017 queue_only_policy = FALSE;
1018 rcpt_smtp_response = NULL;
1019 rcpt_smtp_response_same = TRUE;
1020 rcpt_in_progress = FALSE;
1021 deliver_freeze = FALSE; /* Can be set by ACL */
1022 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1023 fake_response = OK; /* Can be set by ACL */
1024 #ifdef WITH_CONTENT_SCAN
1025 no_mbox_unspool = FALSE; /* Can be set by ACL */
1027 submission_mode = FALSE; /* Can be set by ACL */
1028 suppress_local_fixups = FALSE; /* Can be set by ACL */
1029 active_local_from_check = local_from_check; /* Can be set by ACL */
1030 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1031 sender_address = NULL;
1032 submission_name = NULL; /* Can be set by ACL */
1033 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1034 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1035 sender_verified_list = NULL; /* No senders verified */
1036 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1037 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1038 authenticated_sender = NULL;
1039 #ifdef EXPERIMENTAL_BRIGHTMAIL
1041 bmi_verdicts = NULL;
1043 #ifndef DISABLE_DKIM
1044 dkim_signers = NULL;
1045 dkim_disable_verify = FALSE;
1046 dkim_collect_input = FALSE;
1048 #ifdef EXPERIMENTAL_SPF
1049 spf_header_comment = NULL;
1050 spf_received = NULL;
1052 spf_smtp_comment = NULL;
1054 body_linecount = body_zerocount = 0;
1056 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1057 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1058 /* Note that ratelimiters_conn persists across resets. */
1060 /* Reset message ACL variables */
1064 /* The message body variables use malloc store. They may be set if this is
1065 not the first message in an SMTP session and the previous message caused them
1066 to be referenced in an ACL. */
1068 if (message_body != NULL)
1070 store_free(message_body);
1071 message_body = NULL;
1074 if (message_body_end != NULL)
1076 store_free(message_body_end);
1077 message_body_end = NULL;
1080 /* Warning log messages are also saved in malloc store. They are saved to avoid
1081 repetition in the same message, but it seems right to repeat them for different
1084 while (acl_warn_logged != NULL)
1086 string_item *this = acl_warn_logged;
1087 acl_warn_logged = acl_warn_logged->next;
1096 /*************************************************
1097 * Initialize for incoming batched SMTP message *
1098 *************************************************/
1100 /* This function is called from smtp_setup_msg() in the case when
1101 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1102 of messages in one file with SMTP commands between them. All errors must be
1103 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1104 relevant. After an error on a sender, or an invalid recipient, the remainder
1105 of the message is skipped. The value of received_protocol is already set.
1108 Returns: > 0 message successfully started (reached DATA)
1109 = 0 QUIT read or end of file reached
1110 < 0 should not occur
1114 smtp_setup_batch_msg(void)
1117 void *reset_point = store_get(0);
1119 /* Save the line count at the start of each transaction - single commands
1120 like HELO and RSET count as whole transactions. */
1122 bsmtp_transaction_linecount = receive_linecount;
1124 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1126 smtp_reset(reset_point); /* Reset for start of message */
1128 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1129 value. The values are 2 larger than the required yield of the function. */
1134 uschar *recipient = NULL;
1135 int start, end, sender_domain, recipient_domain;
1137 switch(smtp_read_command(FALSE))
1139 /* The HELO/EHLO commands set sender_address_helo if they have
1140 valid data; otherwise they are ignored, except that they do
1141 a reset of the state. */
1146 check_helo(smtp_cmd_data);
1150 smtp_reset(reset_point);
1151 bsmtp_transaction_linecount = receive_linecount;
1155 /* The MAIL FROM command requires an address as an operand. All we
1156 do here is to parse it for syntactic correctness. The form "<>" is
1157 a special case which converts into an empty string. The start/end
1158 pointers in the original are not used further for this address, as
1159 it is the canonical extracted address which is all that is kept. */
1162 if (sender_address != NULL)
1163 /* The function moan_smtp_batch() does not return. */
1164 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1166 if (smtp_cmd_data[0] == 0)
1167 /* The function moan_smtp_batch() does not return. */
1168 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1170 /* Reset to start of message */
1172 smtp_reset(reset_point);
1174 /* Apply SMTP rewrite */
1176 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1177 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1178 US"", global_rewrite_rules) : smtp_cmd_data;
1180 /* Extract the address; the TRUE flag allows <> as valid */
1183 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1186 if (raw_sender == NULL)
1187 /* The function moan_smtp_batch() does not return. */
1188 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1190 sender_address = string_copy(raw_sender);
1192 /* Qualify unqualified sender addresses if permitted to do so. */
1194 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1196 if (allow_unqualified_sender)
1198 sender_address = rewrite_address_qualify(sender_address, FALSE);
1199 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1200 "and rewritten\n", raw_sender);
1202 /* The function moan_smtp_batch() does not return. */
1203 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1209 /* The RCPT TO command requires an address as an operand. All we do
1210 here is to parse it for syntactic correctness. There may be any number
1211 of RCPT TO commands, specifying multiple senders. We build them all into
1212 a data structure that is in argc/argv format. The start/end values
1213 given by parse_extract_address are not used, as we keep only the
1214 extracted address. */
1217 if (sender_address == NULL)
1218 /* The function moan_smtp_batch() does not return. */
1219 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1221 if (smtp_cmd_data[0] == 0)
1222 /* The function moan_smtp_batch() does not return. */
1223 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1225 /* Check maximum number allowed */
1227 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1228 /* The function moan_smtp_batch() does not return. */
1229 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1230 recipients_max_reject? "552": "452");
1232 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1233 recipient address */
1235 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1236 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1237 global_rewrite_rules) : smtp_cmd_data;
1239 /* rfc821_domains = TRUE; << no longer needed */
1240 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1241 &recipient_domain, FALSE);
1242 /* rfc821_domains = FALSE; << no longer needed */
1244 if (recipient == NULL)
1245 /* The function moan_smtp_batch() does not return. */
1246 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1248 /* If the recipient address is unqualified, qualify it if permitted. Then
1249 add it to the list of recipients. */
1251 if (recipient_domain == 0)
1253 if (allow_unqualified_recipient)
1255 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1257 recipient = rewrite_address_qualify(recipient, TRUE);
1259 /* The function moan_smtp_batch() does not return. */
1260 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1263 receive_add_recipient(recipient, -1);
1267 /* The DATA command is legal only if it follows successful MAIL FROM
1268 and RCPT TO commands. This function is complete when a valid DATA
1269 command is encountered. */
1272 if (sender_address == NULL || recipients_count <= 0)
1274 /* The function moan_smtp_batch() does not return. */
1275 if (sender_address == NULL)
1276 moan_smtp_batch(smtp_cmd_buffer,
1277 "503 MAIL FROM:<sender> command must precede DATA");
1279 moan_smtp_batch(smtp_cmd_buffer,
1280 "503 RCPT TO:<recipient> must precede DATA");
1284 done = 3; /* DATA successfully achieved */
1285 message_ended = END_NOTENDED; /* Indicate in middle of message */
1290 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1297 bsmtp_transaction_linecount = receive_linecount;
1308 /* The function moan_smtp_batch() does not return. */
1309 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1314 /* The function moan_smtp_batch() does not return. */
1315 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1320 /* The function moan_smtp_batch() does not return. */
1321 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1326 return done - 2; /* Convert yield values */
1332 /*************************************************
1333 * Start an SMTP session *
1334 *************************************************/
1336 /* This function is called at the start of an SMTP session. Thereafter,
1337 smtp_setup_msg() is called to initiate each separate message. This
1338 function does host-specific testing, and outputs the banner line.
1341 Returns: FALSE if the session can not continue; something has
1342 gone wrong, or the connection to the host is blocked
1346 smtp_start_session(void)
1350 uschar *user_msg, *log_msg;
1354 smtp_connection_start = time(NULL);
1355 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1356 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1359 /* Default values for certain variables */
1361 helo_seen = esmtp = helo_accept_junk = FALSE;
1362 smtp_mailcmd_count = 0;
1363 count_nonmail = TRUE_UNSET;
1364 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1365 smtp_delay_mail = smtp_rlm_base;
1366 auth_advertised = FALSE;
1367 pipelining_advertised = FALSE;
1368 pipelining_enable = TRUE;
1369 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1370 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1372 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1374 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1375 authentication settings from -oMaa to remain in force. */
1377 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1378 authenticated_by = NULL;
1381 tls_cipher = tls_peerdn = NULL;
1382 tls_advertised = FALSE;
1385 /* Reset ACL connection variables */
1389 /* Allow for trailing 0 in the command and data buffers. */
1391 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1392 if (smtp_cmd_buffer == NULL)
1393 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1394 "malloc() failed for SMTP command buffer");
1395 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1397 /* For batched input, the protocol setting can be overridden from the
1398 command line by a trusted caller. */
1400 if (smtp_batched_input)
1402 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1405 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1406 reset later if any of EHLO/AUTH/STARTTLS are received. */
1410 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1412 /* Set up the buffer for inputting using direct read() calls, and arrange to
1413 call the local functions instead of the standard C ones. */
1415 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1416 if (smtp_inbuffer == NULL)
1417 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1418 receive_getc = smtp_getc;
1419 receive_ungetc = smtp_ungetc;
1420 receive_feof = smtp_feof;
1421 receive_ferror = smtp_ferror;
1422 receive_smtp_buffered = smtp_buffered;
1423 smtp_inptr = smtp_inend = smtp_inbuffer;
1424 smtp_had_eof = smtp_had_error = 0;
1426 /* Set up the message size limit; this may be host-specific */
1428 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1429 if (expand_string_message != NULL)
1431 if (thismessage_size_limit == -1)
1432 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1433 "%s", expand_string_message);
1435 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1436 "%s", expand_string_message);
1437 smtp_closedown(US"Temporary local problem - please try later");
1441 /* When a message is input locally via the -bs or -bS options, sender_host_
1442 unknown is set unless -oMa was used to force an IP address, in which case it
1443 is checked like a real remote connection. When -bs is used from inetd, this
1444 flag is not set, causing the sending host to be checked. The code that deals
1445 with IP source routing (if configured) is never required for -bs or -bS and
1446 the flag sender_host_notsocket is used to suppress it.
1448 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1449 reserve for certain hosts and/or networks. */
1451 if (!sender_host_unknown)
1454 BOOL reserved_host = FALSE;
1456 /* Look up IP options (source routing info) on the socket if this is not an
1457 -oMa "host", and if any are found, log them and drop the connection.
1459 Linux (and others now, see below) is different to everyone else, so there
1460 has to be some conditional compilation here. Versions of Linux before 2.1.15
1461 used a structure whose name was "options". Somebody finally realized that
1462 this name was silly, and it got changed to "ip_options". I use the
1463 newer name here, but there is a fudge in the script that sets up os.h
1464 to define a macro in older Linux systems.
1466 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1467 glibc 2, which has chosen ip_opts for the structure name. This is now
1468 really a glibc thing rather than a Linux thing, so the condition name
1469 has been changed to reflect this. It is relevant also to GNU/Hurd.
1471 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1472 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1473 a special macro defined in the os.h file.
1475 Some DGUX versions on older hardware appear not to support IP options at
1476 all, so there is now a general macro which can be set to cut out this
1479 How to do this properly in IPv6 is not yet known. */
1481 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1483 #ifdef GLIBC_IP_OPTIONS
1484 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1489 #elif defined DARWIN_IP_OPTIONS
1495 if (!host_checking && !sender_host_notsocket)
1498 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1499 struct ip_options *ipopt = store_get(optlen);
1501 struct ip_opts ipoptblock;
1502 struct ip_opts *ipopt = &ipoptblock;
1503 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1505 struct ipoption ipoptblock;
1506 struct ipoption *ipopt = &ipoptblock;
1507 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1510 /* Occasional genuine failures of getsockopt() have been seen - for
1511 example, "reset by peer". Therefore, just log and give up on this
1512 call, unless the error is ENOPROTOOPT. This error is given by systems
1513 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1514 of writing. So for that error, carry on - we just can't do an IP options
1517 DEBUG(D_receive) debug_printf("checking for IP options\n");
1519 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1522 if (errno != ENOPROTOOPT)
1524 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1525 host_and_ident(FALSE), strerror(errno));
1526 smtp_printf("451 SMTP service not available\r\n");
1531 /* Deal with any IP options that are set. On the systems I have looked at,
1532 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1533 more logging data than will fit in big_buffer. Nevertheless, after somebody
1534 questioned this code, I've added in some paranoid checking. */
1536 else if (optlen > 0)
1538 uschar *p = big_buffer;
1539 uschar *pend = big_buffer + big_buffer_size;
1540 uschar *opt, *adptr;
1542 struct in_addr addr;
1545 uschar *optstart = (uschar *)(ipopt->__data);
1547 uschar *optstart = (uschar *)(ipopt->ip_opts);
1549 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1552 DEBUG(D_receive) debug_printf("IP options exist\n");
1554 Ustrcpy(p, "IP options on incoming call:");
1557 for (opt = optstart; opt != NULL &&
1558 opt < (uschar *)(ipopt) + optlen;)
1572 if (!string_format(p, pend-p, " %s [@%s",
1573 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1575 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1577 inet_ntoa(ipopt->ip_dst)))
1579 inet_ntoa(ipopt->ipopt_dst)))
1587 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1589 while (optcount-- > 0)
1591 memcpy(&addr, adptr, sizeof(addr));
1592 if (!string_format(p, pend - p - 1, "%s%s",
1593 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1599 adptr += sizeof(struct in_addr);
1608 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1611 for (i = 0; i < opt[1]; i++)
1613 sprintf(CS p, "%2.2x ", opt[i]);
1624 log_write(0, LOG_MAIN, "%s", big_buffer);
1626 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1628 log_write(0, LOG_MAIN|LOG_REJECT,
1629 "connection from %s refused (IP options)", host_and_ident(FALSE));
1631 smtp_printf("554 SMTP service not available\r\n");
1635 /* Length of options = 0 => there are no options */
1637 else DEBUG(D_receive) debug_printf("no IP options found\n");
1639 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1641 /* Set keep-alive in socket options. The option is on by default. This
1642 setting is an attempt to get rid of some hanging connections that stick in
1643 read() when the remote end (usually a dialup) goes away. */
1645 if (smtp_accept_keepalive && !sender_host_notsocket)
1646 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1648 /* If the current host matches host_lookup, set the name by doing a
1649 reverse lookup. On failure, sender_host_name will be NULL and
1650 host_lookup_failed will be TRUE. This may or may not be serious - optional
1653 if (verify_check_host(&host_lookup) == OK)
1655 (void)host_name_lookup();
1656 host_build_sender_fullhost();
1659 /* Delay this until we have the full name, if it is looked up. */
1661 set_process_info("handling incoming connection from %s",
1662 host_and_ident(FALSE));
1664 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1665 smtps port for use with older style SSL MTAs. */
1668 if (tls_on_connect &&
1669 tls_server_start(tls_require_ciphers,
1670 gnutls_require_mac, gnutls_require_kx, gnutls_require_proto) != OK)
1674 /* Test for explicit connection rejection */
1676 if (verify_check_host(&host_reject_connection) == OK)
1678 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1679 "from %s (host_reject_connection)", host_and_ident(FALSE));
1680 smtp_printf("554 SMTP service not available\r\n");
1684 /* Test with TCP Wrappers if so configured. There is a problem in that
1685 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1686 such as disks dying. In these cases, it is desirable to reject with a 4xx
1687 error instead of a 5xx error. There isn't a "right" way to detect such
1688 problems. The following kludge is used: errno is zeroed before calling
1689 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1690 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1693 #ifdef USE_TCP_WRAPPERS
1695 if (!hosts_ctl("exim",
1696 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1697 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1698 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1700 if (errno == 0 || errno == ENOENT)
1702 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1703 log_write(L_connection_reject,
1704 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1705 "(tcp wrappers)", host_and_ident(FALSE));
1706 smtp_printf("554 SMTP service not available\r\n");
1710 int save_errno = errno;
1711 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1712 "errno value %d\n", save_errno);
1713 log_write(L_connection_reject,
1714 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1715 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1716 smtp_printf("451 Temporary local problem - please try later\r\n");
1722 /* Check for reserved slots. The value of smtp_accept_count has already been
1723 incremented to include this process. */
1725 if (smtp_accept_max > 0 &&
1726 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
1728 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1730 log_write(L_connection_reject,
1731 LOG_MAIN, "temporarily refused connection from %s: not in "
1732 "reserve list: connected=%d max=%d reserve=%d%s",
1733 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
1734 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1735 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1736 "please try again later\r\n", smtp_active_hostname);
1739 reserved_host = TRUE;
1742 /* If a load level above which only messages from reserved hosts are
1743 accepted is set, check the load. For incoming calls via the daemon, the
1744 check is done in the superior process if there are no reserved hosts, to
1745 save a fork. In all cases, the load average will already be available
1746 in a global variable at this point. */
1748 if (smtp_load_reserve >= 0 &&
1749 load_average > smtp_load_reserve &&
1751 verify_check_host(&smtp_reserve_hosts) != OK)
1753 log_write(L_connection_reject,
1754 LOG_MAIN, "temporarily refused connection from %s: not in "
1755 "reserve list and load average = %.2f", host_and_ident(FALSE),
1756 (double)load_average/1000.0);
1757 smtp_printf("421 %s: Too much load; please try again later\r\n",
1758 smtp_active_hostname);
1762 /* Determine whether unqualified senders or recipients are permitted
1763 for this host. Unfortunately, we have to do this every time, in order to
1764 set the flags so that they can be inspected when considering qualifying
1765 addresses in the headers. For a site that permits no qualification, this
1766 won't take long, however. */
1768 allow_unqualified_sender =
1769 verify_check_host(&sender_unqualified_hosts) == OK;
1771 allow_unqualified_recipient =
1772 verify_check_host(&recipient_unqualified_hosts) == OK;
1774 /* Determine whether HELO/EHLO is required for this host. The requirement
1775 can be hard or soft. */
1777 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1779 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1781 /* Determine whether this hosts is permitted to send syntactic junk
1782 after a HELO or EHLO command. */
1784 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1787 /* For batch SMTP input we are now done. */
1789 if (smtp_batched_input) return TRUE;
1791 /* Run the ACL if it exists */
1794 if (acl_smtp_connect != NULL)
1797 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1801 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1806 /* Output the initial message for a two-way SMTP connection. It may contain
1807 newlines, which then cause a multi-line response to be given. */
1809 code = US"220"; /* Default status code */
1810 esc = US""; /* Default extended status code */
1811 esclen = 0; /* Length of esc */
1813 if (user_msg == NULL)
1815 s = expand_string(smtp_banner);
1817 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1818 "failed: %s", smtp_banner, expand_string_message);
1824 smtp_message_code(&code, &codelen, &s, NULL);
1828 esclen = codelen - 4;
1832 /* Remove any terminating newlines; might as well remove trailing space too */
1835 while (p > s && isspace(p[-1])) p--;
1838 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1839 is all contained in a single IP packet. The original code wrote out the
1840 greeting using several calls to fprint/fputc, and on busy servers this could
1841 cause it to be split over more than one packet - which caused CC:Mail to fall
1842 over when it got the second part of the greeting after sending its first
1843 command. Sigh. To try to avoid this, build the complete greeting message
1844 first, and output it in one fell swoop. This gives a better chance of it
1845 ending up as a single packet. */
1847 ss = store_get(size);
1851 do /* At least once, in case we have an empty string */
1854 uschar *linebreak = Ustrchr(p, '\n');
1855 ss = string_cat(ss, &size, &ptr, code, 3);
1856 if (linebreak == NULL)
1859 ss = string_cat(ss, &size, &ptr, US" ", 1);
1863 len = linebreak - p;
1864 ss = string_cat(ss, &size, &ptr, US"-", 1);
1866 ss = string_cat(ss, &size, &ptr, esc, esclen);
1867 ss = string_cat(ss, &size, &ptr, p, len);
1868 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1870 if (linebreak != NULL) p++;
1874 ss[ptr] = 0; /* string_cat leaves room for this */
1876 /* Before we write the banner, check that there is no input pending, unless
1877 this synchronisation check is disabled. */
1881 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1882 "synchronization error (input sent without waiting for greeting): "
1883 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1884 string_printing(smtp_inptr));
1885 smtp_printf("554 SMTP synchronization error\r\n");
1889 /* Now output the banner */
1891 smtp_printf("%s", ss);
1899 /*************************************************
1900 * Handle SMTP syntax and protocol errors *
1901 *************************************************/
1903 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1904 to do so. Then transmit the error response. The return value depends on the
1905 number of syntax and protocol errors in this SMTP session.
1908 type error type, given as a log flag bit
1909 code response code; <= 0 means don't send a response
1910 data data to reflect in the response (can be NULL)
1911 errmess the error message
1913 Returns: -1 limit of syntax/protocol errors NOT exceeded
1914 +1 limit of syntax/protocol errors IS exceeded
1916 These values fit in with the values of the "done" variable in the main
1917 processing loop in smtp_setup_msg(). */
1920 synprot_error(int type, int code, uschar *data, uschar *errmess)
1924 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1925 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1926 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1928 if (++synprot_error_count > smtp_max_synprot_errors)
1931 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1932 "syntax or protocol errors (last command was \"%s\")",
1933 host_and_ident(FALSE), smtp_cmd_buffer);
1938 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1939 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1941 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1950 /*************************************************
1951 * Log incomplete transactions *
1952 *************************************************/
1954 /* This function is called after a transaction has been aborted by RSET, QUIT,
1955 connection drops or other errors. It logs the envelope information received
1956 so far in order to preserve address verification attempts.
1958 Argument: string to indicate what aborted the transaction
1963 incomplete_transaction_log(uschar *what)
1965 if (sender_address == NULL || /* No transaction in progress */
1966 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1969 /* Build list of recipients for logging */
1971 if (recipients_count > 0)
1974 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1975 for (i = 0; i < recipients_count; i++)
1976 raw_recipients[i] = recipients_list[i].address;
1977 raw_recipients_count = recipients_count;
1980 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1981 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1987 /*************************************************
1988 * Send SMTP response, possibly multiline *
1989 *************************************************/
1991 /* There are, it seems, broken clients out there that cannot handle multiline
1992 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1993 output nothing for non-final calls, and only the first line for anything else.
1996 code SMTP code, may involve extended status codes
1997 codelen length of smtp code; if > 4 there's an ESC
1998 final FALSE if the last line isn't the final line
1999 msg message text, possibly containing newlines
2005 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2010 if (!final && no_multiline_responses) return;
2015 esclen = codelen - 4;
2018 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2019 have had the same. Note: this code is also present in smtp_printf(). It would
2020 be tidier to have it only in one place, but when it was added, it was easier to
2021 do it that way, so as not to have to mess with the code for the RCPT command,
2022 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2024 if (rcpt_in_progress)
2026 if (rcpt_smtp_response == NULL)
2027 rcpt_smtp_response = string_copy(msg);
2028 else if (rcpt_smtp_response_same &&
2029 Ustrcmp(rcpt_smtp_response, msg) != 0)
2030 rcpt_smtp_response_same = FALSE;
2031 rcpt_in_progress = FALSE;
2034 /* Not output the message, splitting it up into multiple lines if necessary. */
2038 uschar *nl = Ustrchr(msg, '\n');
2041 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2044 else if (nl[1] == 0 || no_multiline_responses)
2046 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2047 (int)(nl - msg), msg);
2052 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2054 while (isspace(*msg)) msg++;
2062 /*************************************************
2063 * Parse user SMTP message *
2064 *************************************************/
2066 /* This function allows for user messages overriding the response code details
2067 by providing a suitable response code string at the start of the message
2068 user_msg. Check the message for starting with a response code and optionally an
2069 extended status code. If found, check that the first digit is valid, and if so,
2070 change the code pointer and length to use the replacement. An invalid code
2071 causes a panic log; in this case, if the log messages is the same as the user
2072 message, we must also adjust the value of the log message to show the code that
2073 is actually going to be used (the original one).
2075 This function is global because it is called from receive.c as well as within
2078 Note that the code length returned includes the terminating whitespace
2079 character, which is always included in the regex match.
2082 code SMTP code, may involve extended status codes
2083 codelen length of smtp code; if > 4 there's an ESC
2085 log_msg optional log message, to be adjusted with the new SMTP code
2091 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2096 if (msg == NULL || *msg == NULL) return;
2098 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2099 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2102 if ((*msg)[0] != (*code)[0])
2104 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2105 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2106 if (log_msg != NULL && *log_msg == *msg)
2107 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2112 *codelen = ovector[1]; /* Includes final space */
2114 *msg += ovector[1]; /* Chop the code off the message */
2121 /*************************************************
2122 * Handle an ACL failure *
2123 *************************************************/
2125 /* This function is called when acl_check() fails. As well as calls from within
2126 this module, it is called from receive.c for an ACL after DATA. It sorts out
2127 logging the incident, and sets up the error response. A message containing
2128 newlines is turned into a multiline SMTP response, but for logging, only the
2131 There's a table of default permanent failure response codes to use in
2132 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2133 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2134 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2135 state, because there are broken clients that try VRFY before RCPT. A 5xx
2136 response should be given only when the address is positively known to be
2137 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2140 From Exim 4.63, it is possible to override the response code details by
2141 providing a suitable response code string at the start of the message provided
2142 in user_msg. The code's first digit is checked for validity.
2145 where where the ACL was called from
2147 user_msg a message that can be included in an SMTP response
2148 log_msg a message for logging
2150 Returns: 0 in most cases
2151 2 if the failure code was FAIL_DROP, in which case the
2152 SMTP connection should be dropped (this value fits with the
2153 "done" variable in smtp_setup_msg() below)
2157 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2159 BOOL drop = rc == FAIL_DROP;
2163 uschar *sender_info = US"";
2165 #ifdef WITH_CONTENT_SCAN
2166 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2168 (where == ACL_WHERE_PREDATA)? US"DATA" :
2169 (where == ACL_WHERE_DATA)? US"after DATA" :
2170 (smtp_cmd_data == NULL)?
2171 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2172 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2174 if (drop) rc = FAIL;
2176 /* Set the default SMTP code, and allow a user message to change it. */
2178 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2179 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2181 /* We used to have sender_address here; however, there was a bug that was not
2182 updating sender_address after a rewrite during a verify. When this bug was
2183 fixed, sender_address at this point became the rewritten address. I'm not sure
2184 this is what should be logged, so I've changed to logging the unrewritten
2185 address to retain backward compatibility. */
2187 #ifndef WITH_CONTENT_SCAN
2188 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2190 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2193 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
2194 sender_address_unrewritten : sender_address);
2197 /* If there's been a sender verification failure with a specific message, and
2198 we have not sent a response about it yet, do so now, as a preliminary line for
2199 failures, but not defers. However, always log it for defer, and log it for fail
2200 unless the sender_verify_fail log selector has been turned off. */
2202 if (sender_verified_failed != NULL &&
2203 !testflag(sender_verified_failed, af_sverify_told))
2205 BOOL save_rcpt_in_progress = rcpt_in_progress;
2206 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2208 setflag(sender_verified_failed, af_sverify_told);
2210 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2211 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2212 host_and_ident(TRUE),
2213 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2214 sender_verified_failed->address,
2215 (sender_verified_failed->message == NULL)? US"" :
2216 string_sprintf(": %s", sender_verified_failed->message));
2218 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2219 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2220 testflag(sender_verified_failed, af_verify_pmfail)?
2221 "Postmaster verification failed while checking <%s>\n%s\n"
2222 "Several RFCs state that you are required to have a postmaster\n"
2223 "mailbox for each mail domain. This host does not accept mail\n"
2224 "from domains whose servers reject the postmaster address."
2226 testflag(sender_verified_failed, af_verify_nsfail)?
2227 "Callback setup failed while verifying <%s>\n%s\n"
2228 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2229 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2230 "RFC requirements, and stops you from receiving standard bounce\n"
2231 "messages. This host does not accept mail from domains whose servers\n"
2234 "Verification failed for <%s>\n%s",
2235 sender_verified_failed->address,
2236 sender_verified_failed->user_message));
2238 rcpt_in_progress = save_rcpt_in_progress;
2241 /* Sort out text for logging */
2243 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2244 lognl = Ustrchr(log_msg, '\n');
2245 if (lognl != NULL) *lognl = 0;
2247 /* Send permanent failure response to the command, but the code used isn't
2248 always a 5xx one - see comments at the start of this function. If the original
2249 rc was FAIL_DROP we drop the connection and yield 2. */
2251 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2252 US"Administrative prohibition" : user_msg);
2254 /* Send temporary failure response to the command. Don't give any details,
2255 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2256 verb, and for a header verify when smtp_return_error_details is set.
2258 This conditional logic is all somewhat of a mess because of the odd
2259 interactions between temp_details and return_error_details. One day it should
2260 be re-implemented in a tidier fashion. */
2264 if (acl_temp_details && user_msg != NULL)
2266 if (smtp_return_error_details &&
2267 sender_verified_failed != NULL &&
2268 sender_verified_failed->message != NULL)
2270 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2272 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2275 smtp_respond(smtp_code, codelen, TRUE,
2276 US"Temporary local problem - please try later");
2279 /* Log the incident to the logs that are specified by log_reject_target
2280 (default main, reject). This can be empty to suppress logging of rejections. If
2281 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2282 is closing if required and return 2. */
2284 if (log_reject_target != 0)
2285 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2286 host_and_ident(TRUE),
2287 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2289 if (!drop) return 0;
2291 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2292 smtp_get_connection_info());
2294 /* Run the not-quit ACL, but without any custom messages. This should not be a
2295 problem, because we get here only if some other ACL has issued "drop", and
2296 in that case, *its* custom messages will have been used above. */
2298 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2305 /*************************************************
2306 * Handle SMTP exit when QUIT is not given *
2307 *************************************************/
2309 /* This function provides a logging/statistics hook for when an SMTP connection
2310 is dropped on the floor or the other end goes away. It's a global function
2311 because it's called from receive.c as well as this module. As well as running
2312 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2313 response, either with a custom message from the ACL, or using a default. There
2314 is one case, however, when no message is output - after "drop". In that case,
2315 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2316 passed to this function.
2318 In case things go wrong while processing this function, causing an error that
2319 may re-enter this funtion, there is a recursion check.
2322 reason What $smtp_notquit_reason will be set to in the ACL;
2323 if NULL, the ACL is not run
2324 code The error code to return as part of the response
2325 defaultrespond The default message if there's no user_msg
2331 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2334 uschar *user_msg = NULL;
2335 uschar *log_msg = NULL;
2337 /* Check for recursive acll */
2339 if (smtp_exit_function_called)
2341 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2345 smtp_exit_function_called = TRUE;
2347 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2349 if (acl_smtp_notquit != NULL && reason != NULL)
2351 smtp_notquit_reason = reason;
2352 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2355 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2359 /* Write an SMTP response if we are expected to give one. As the default
2360 responses are all internal, they should always fit in the buffer, but code a
2361 warning, just in case. Note that string_vformat() still leaves a complete
2362 string, even if it is incomplete. */
2364 if (code != NULL && defaultrespond != NULL)
2366 if (user_msg == NULL)
2370 va_start(ap, defaultrespond);
2371 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2372 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2373 smtp_printf("%s %s\r\n", code, buffer);
2377 smtp_respond(code, 3, TRUE, user_msg);
2385 /*************************************************
2386 * Verify HELO argument *
2387 *************************************************/
2389 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2390 matched. It is also called from ACL processing if verify = helo is used and
2391 verification was not previously tried (i.e. helo_try_verify_hosts was not
2392 matched). The result of its processing is to set helo_verified and
2393 helo_verify_failed. These variables should both be FALSE for this function to
2396 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2397 for IPv6 ::ffff: literals.
2400 Returns: TRUE if testing was completed;
2401 FALSE on a temporary failure
2405 smtp_verify_helo(void)
2409 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2412 if (sender_helo_name == NULL)
2414 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2417 /* Deal with the case of -bs without an IP address */
2419 else if (sender_host_address == NULL)
2421 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2422 helo_verified = TRUE;
2425 /* Deal with the more common case when there is a sending IP address */
2427 else if (sender_helo_name[0] == '[')
2429 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2430 Ustrlen(sender_host_address)) == 0;
2435 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2436 helo_verified = Ustrncmp(sender_helo_name + 1,
2437 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2442 { if (helo_verified) debug_printf("matched host address\n"); }
2445 /* Do a reverse lookup if one hasn't already given a positive or negative
2446 response. If that fails, or the name doesn't match, try checking with a forward
2451 if (sender_host_name == NULL && !host_lookup_failed)
2452 yield = host_name_lookup() != DEFER;
2454 /* If a host name is known, check it and all its aliases. */
2456 if (sender_host_name != NULL)
2458 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2462 HDEBUG(D_receive) debug_printf("matched host name\n");
2466 uschar **aliases = sender_host_aliases;
2467 while (*aliases != NULL)
2469 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2470 if (helo_verified) break;
2475 debug_printf("matched alias %s\n", *(--aliases));
2480 /* Final attempt: try a forward lookup of the helo name */
2486 h.name = sender_helo_name;
2490 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2492 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2493 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2498 if (Ustrcmp(hh->address, sender_host_address) == 0)
2500 helo_verified = TRUE;
2502 debug_printf("IP address for %s matches calling address\n",
2512 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2519 /*************************************************
2520 * Send user response message *
2521 *************************************************/
2523 /* This function is passed a default response code and a user message. It calls
2524 smtp_message_code() to check and possibly modify the response code, and then
2525 calls smtp_respond() to transmit the response. I put this into a function
2526 just to avoid a lot of repetition.
2529 code the response code
2530 user_msg the user message
2536 smtp_user_msg(uschar *code, uschar *user_msg)
2539 smtp_message_code(&code, &len, &user_msg, NULL);
2540 smtp_respond(code, len, TRUE, user_msg);
2546 /*************************************************
2547 * Initialize for SMTP incoming message *
2548 *************************************************/
2550 /* This function conducts the initial dialogue at the start of an incoming SMTP
2551 message, and builds a list of recipients. However, if the incoming message
2552 is part of a batch (-bS option) a separate function is called since it would
2553 be messy having tests splattered about all over this function. This function
2554 therefore handles the case where interaction is occurring. The input and output
2555 files are set up in smtp_in and smtp_out.
2557 The global recipients_list is set to point to a vector of recipient_item
2558 blocks, whose number is given by recipients_count. This is extended by the
2559 receive_add_recipient() function. The global variable sender_address is set to
2560 the sender's address. The yield is +1 if a message has been successfully
2561 started, 0 if a QUIT command was encountered or the connection was refused from
2562 the particular host, or -1 if the connection was lost.
2566 Returns: > 0 message successfully started (reached DATA)
2567 = 0 QUIT read or end of file reached or call refused
2572 smtp_setup_msg(void)
2575 BOOL toomany = FALSE;
2576 BOOL discarded = FALSE;
2577 BOOL last_was_rej_mail = FALSE;
2578 BOOL last_was_rcpt = FALSE;
2579 void *reset_point = store_get(0);
2581 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2583 /* Reset for start of new message. We allow one RSET not to be counted as a
2584 nonmail command, for those MTAs that insist on sending it between every
2585 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2586 TLS between messages (an Exim client may do this if it has messages queued up
2587 for the host). Note: we do NOT reset AUTH at this point. */
2589 smtp_reset(reset_point);
2590 message_ended = END_NOTSTARTED;
2592 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2593 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2594 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2596 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2599 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2601 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2603 /* Batched SMTP is handled in a different function. */
2605 if (smtp_batched_input) return smtp_setup_batch_msg();
2607 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2608 value. The values are 2 larger than the required yield of the function. */
2613 uschar *etrn_command;
2614 uschar *etrn_serialize_key;
2616 uschar *log_msg, *smtp_code;
2617 uschar *user_msg = NULL;
2618 uschar *recipient = NULL;
2619 uschar *hello = NULL;
2620 uschar *set_id = NULL;
2622 BOOL was_rej_mail = FALSE;
2623 BOOL was_rcpt = FALSE;
2624 void (*oldsignal)(int);
2626 int start, end, sender_domain, recipient_domain;
2631 switch(smtp_read_command(TRUE))
2633 /* The AUTH command is not permitted to occur inside a transaction, and may
2634 occur successfully only once per connection. Actually, that isn't quite
2635 true. When TLS is started, all previous information about a connection must
2636 be discarded, so a new AUTH is permitted at that time.
2638 AUTH may only be used when it has been advertised. However, it seems that
2639 there are clients that send AUTH when it hasn't been advertised, some of
2640 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2641 So there's a get-out that allows this to happen.
2643 AUTH is initially labelled as a "nonmail command" so that one occurrence
2644 doesn't get counted. We change the label here so that multiple failing
2645 AUTHS will eventually hit the nonmail threshold. */
2649 authentication_failed = TRUE;
2650 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2652 if (!auth_advertised && !allow_auth_unadvertised)
2654 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2655 US"AUTH command used when not advertised");
2658 if (sender_host_authenticated != NULL)
2660 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2661 US"already authenticated");
2664 if (sender_address != NULL)
2666 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2667 US"not permitted in mail transaction");
2673 if (acl_smtp_auth != NULL)
2675 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2678 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2683 /* Find the name of the requested authentication mechanism. */
2686 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
2688 if (!isalnum(c) && c != '-' && c != '_')
2690 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2691 US"invalid character in authentication mechanism name");
2697 /* If not at the end of the line, we must be at white space. Terminate the
2698 name and move the pointer on to any data that may be present. */
2700 if (*smtp_cmd_data != 0)
2702 *smtp_cmd_data++ = 0;
2703 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
2706 /* Search for an authentication mechanism which is configured for use
2707 as a server and which has been advertised (unless, sigh, allow_auth_
2708 unadvertised is set). */
2710 for (au = auths; au != NULL; au = au->next)
2712 if (strcmpic(s, au->public_name) == 0 && au->server &&
2713 (au->advertised || allow_auth_unadvertised)) break;
2718 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2719 string_sprintf("%s authentication mechanism not supported", s));
2723 /* Run the checking code, passing the remainder of the command line as
2724 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2725 it as the only set numerical variable. The authenticator may set $auth<n>
2726 and also set other numeric variables. The $auth<n> variables are preferred
2727 nowadays; the numerical variables remain for backwards compatibility.
2729 Afterwards, have a go at expanding the set_id string, even if
2730 authentication failed - for bad passwords it can be useful to log the
2731 userid. On success, require set_id to expand and exist, and put it in
2732 authenticated_id. Save this in permanent store, as the working store gets
2733 reset at HELO, RSET, etc. */
2735 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2737 expand_nlength[0] = 0; /* $0 contains nothing */
2739 c = (au->info->servercode)(au, smtp_cmd_data);
2740 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2741 expand_nmax = -1; /* Reset numeric variables */
2742 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2744 /* The value of authenticated_id is stored in the spool file and printed in
2745 log lines. It must not contain binary zeros or newline characters. In
2746 normal use, it never will, but when playing around or testing, this error
2747 can (did) happen. To guard against this, ensure that the id contains only
2748 printing characters. */
2750 if (set_id != NULL) set_id = string_printing(set_id);
2752 /* For the non-OK cases, set up additional logging data if set_id
2757 if (set_id != NULL && *set_id != 0)
2758 set_id = string_sprintf(" (set_id=%s)", set_id);
2762 /* Switch on the result */
2767 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2769 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2770 sender_host_authenticated = au->name;
2771 authentication_failed = FALSE;
2773 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2774 ((sender_host_address != NULL)? pnlocal : 0);
2775 s = ss = US"235 Authentication succeeded";
2776 authenticated_by = au;
2780 /* Authentication succeeded, but we failed to expand the set_id string.
2781 Treat this as a temporary error. */
2783 auth_defer_msg = expand_string_message;
2787 s = string_sprintf("435 Unable to authenticate at present%s",
2788 auth_defer_user_msg);
2789 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2790 set_id, auth_defer_msg);
2794 s = ss = US"501 Invalid base64 data";
2798 s = ss = US"501 Authentication cancelled";
2802 s = ss = US"553 Initial data not expected";
2806 s = US"535 Incorrect authentication data";
2807 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2811 s = US"435 Internal error";
2812 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2813 "check", set_id, c);
2817 smtp_printf("%s\r\n", s);
2819 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2820 au->name, host_and_ident(FALSE), ss);
2822 break; /* AUTH_CMD */
2824 /* The HELO/EHLO commands are permitted to appear in the middle of a
2825 session as well as at the beginning. They have the effect of a reset in
2826 addition to their other functions. Their absence at the start cannot be
2827 taken to be an error.
2831 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2832 or 502 failure replies MUST be returned as appropriate. The SMTP
2833 server MUST stay in the same state after transmitting these replies
2834 that it was in before the EHLO was received.
2836 Therefore, we do not do the reset until after checking the command for
2837 acceptability. This change was made for Exim release 4.11. Previously
2838 it did the reset first. */
2851 HELO_EHLO: /* Common code for HELO and EHLO */
2852 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2853 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2855 /* Reject the HELO if its argument was invalid or non-existent. A
2856 successful check causes the argument to be saved in malloc store. */
2858 if (!check_helo(smtp_cmd_data))
2860 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2862 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2863 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2864 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2865 string_printing(smtp_cmd_argument));
2867 if (++synprot_error_count > smtp_max_synprot_errors)
2869 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2870 "syntax or protocol errors (last command was \"%s\")",
2871 host_and_ident(FALSE), smtp_cmd_buffer);
2878 /* If sender_host_unknown is true, we have got here via the -bs interface,
2879 not called from inetd. Otherwise, we are running an IP connection and the
2880 host address will be set. If the helo name is the primary name of this
2881 host and we haven't done a reverse lookup, force one now. If helo_required
2882 is set, ensure that the HELO name matches the actual host. If helo_verify
2883 is set, do the same check, but softly. */
2885 if (!sender_host_unknown)
2887 BOOL old_helo_verified = helo_verified;
2888 uschar *p = smtp_cmd_data;
2890 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2893 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2894 because otherwise the log can be confusing. */
2896 if (sender_host_name == NULL &&
2897 (deliver_domain = sender_helo_name, /* set $domain */
2898 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2899 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2900 (void)host_name_lookup();
2902 /* Rebuild the fullhost info to include the HELO name (and the real name
2903 if it was looked up.) */
2905 host_build_sender_fullhost(); /* Rebuild */
2906 set_process_info("handling%s incoming connection from %s",
2907 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2909 /* Verify if configured. This doesn't give much security, but it does
2910 make some people happy to be able to do it. If helo_required is set,
2911 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2912 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2913 now obsolescent, since the verification can now be requested selectively
2916 helo_verified = helo_verify_failed = FALSE;
2917 if (helo_required || helo_verify)
2919 BOOL tempfail = !smtp_verify_helo();
2924 smtp_printf("%d %s argument does not match calling host\r\n",
2925 tempfail? 451 : 550, hello);
2926 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2927 tempfail? "temporarily " : "",
2928 hello, sender_helo_name, host_and_ident(FALSE));
2929 helo_verified = old_helo_verified;
2930 break; /* End of HELO/EHLO processing */
2932 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2933 "helo_try_verify_hosts\n", hello);
2938 #ifdef EXPERIMENTAL_SPF
2939 /* set up SPF context */
2940 spf_init(sender_helo_name, sender_host_address);
2943 /* Apply an ACL check if one is defined; afterwards, recheck
2944 synchronization in case the client started sending in a delay. */
2946 if (acl_smtp_helo != NULL)
2948 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2951 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2952 sender_helo_name = NULL;
2953 host_build_sender_fullhost(); /* Rebuild */
2956 else if (!check_sync()) goto SYNC_FAILURE;
2959 /* Generate an OK reply. The default string includes the ident if present,
2960 and also the IP address if present. Reflecting back the ident is intended
2961 as a deterrent to mail forgers. For maximum efficiency, and also because
2962 some broken systems expect each response to be in a single packet, arrange
2963 that the entire reply is sent in one write(). */
2965 auth_advertised = FALSE;
2966 pipelining_advertised = FALSE;
2968 tls_advertised = FALSE;
2971 smtp_code = US"250 "; /* Default response code plus space*/
2972 if (user_msg == NULL)
2974 s = string_sprintf("%.3s %s Hello %s%s%s",
2976 smtp_active_hostname,
2977 (sender_ident == NULL)? US"" : sender_ident,
2978 (sender_ident == NULL)? US"" : US" at ",
2979 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2984 if (sender_host_address != NULL)
2986 s = string_cat(s, &size, &ptr, US" [", 2);
2987 s = string_cat(s, &size, &ptr, sender_host_address,
2988 Ustrlen(sender_host_address));
2989 s = string_cat(s, &size, &ptr, US"]", 1);
2993 /* A user-supplied EHLO greeting may not contain more than one line. Note
2994 that the code returned by smtp_message_code() includes the terminating
2995 whitespace character. */
3001 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3002 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3003 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3005 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3006 "newlines: message truncated: %s", string_printing(s));
3013 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3015 /* If we received EHLO, we must create a multiline response which includes
3016 the functions supported. */
3022 /* I'm not entirely happy with this, as an MTA is supposed to check
3023 that it has enough room to accept a message of maximum size before
3024 it sends this. However, there seems little point in not sending it.
3025 The actual size check happens later at MAIL FROM time. By postponing it
3026 till then, VRFY and EXPN can be used after EHLO when space is short. */
3028 if (thismessage_size_limit > 0)
3030 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3031 thismessage_size_limit);
3032 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3036 s = string_cat(s, &size, &ptr, smtp_code, 3);
3037 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3040 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3041 clean; if it has an 8-bit character in its hand, it just sends it. It
3042 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3043 However, some users want this option simply in order to stop MUAs
3044 mangling messages that contain top-bit-set characters. It is therefore
3045 provided as an option. */
3047 if (accept_8bitmime)
3049 s = string_cat(s, &size, &ptr, smtp_code, 3);
3050 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3053 /* Advertise ETRN if there's an ACL checking whether a host is
3054 permitted to issue it; a check is made when any host actually tries. */
3056 if (acl_smtp_etrn != NULL)
3058 s = string_cat(s, &size, &ptr, smtp_code, 3);
3059 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3062 /* Advertise EXPN if there's an ACL checking whether a host is
3063 permitted to issue it; a check is made when any host actually tries. */
3065 if (acl_smtp_expn != NULL)
3067 s = string_cat(s, &size, &ptr, smtp_code, 3);
3068 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3071 /* Exim is quite happy with pipelining, so let the other end know that
3072 it is safe to use it, unless advertising is disabled. */
3074 if (pipelining_enable &&
3075 verify_check_host(&pipelining_advertise_hosts) == OK)
3077 s = string_cat(s, &size, &ptr, smtp_code, 3);
3078 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3079 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3080 pipelining_advertised = TRUE;
3083 /* If any server authentication mechanisms are configured, advertise
3084 them if the current host is in auth_advertise_hosts. The problem with
3085 advertising always is that some clients then require users to
3086 authenticate (and aren't configurable otherwise) even though it may not
3087 be necessary (e.g. if the host is in host_accept_relay).
3089 RFC 2222 states that SASL mechanism names contain only upper case
3090 letters, so output the names in upper case, though we actually recognize
3091 them in either case in the AUTH command. */
3095 if (verify_check_host(&auth_advertise_hosts) == OK)
3099 for (au = auths; au != NULL; au = au->next)
3101 if (au->server && (au->advertise_condition == NULL ||
3102 expand_check_condition(au->advertise_condition, au->name,
3103 US"authenticator")))
3108 s = string_cat(s, &size, &ptr, smtp_code, 3);
3109 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3111 auth_advertised = TRUE;
3114 s = string_cat(s, &size, &ptr, US" ", 1);
3115 s = string_cat(s, &size, &ptr, au->public_name,
3116 Ustrlen(au->public_name));
3117 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3118 au->advertised = TRUE;
3120 else au->advertised = FALSE;
3122 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3126 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3127 if it has been included in the binary, and the host matches
3128 tls_advertise_hosts. We must *not* advertise if we are already in a
3129 secure connection. */
3132 if (tls_active < 0 &&
3133 verify_check_host(&tls_advertise_hosts) != FAIL)
3135 s = string_cat(s, &size, &ptr, smtp_code, 3);
3136 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3137 tls_advertised = TRUE;
3141 /* Finish off the multiline reply with one that is always available. */
3143 s = string_cat(s, &size, &ptr, smtp_code, 3);
3144 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3147 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3153 if (tls_active >= 0) (void)tls_write(s, ptr); else
3156 (void)fwrite(s, 1, ptr, smtp_out);
3160 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3161 memmove(cr, cr + 1, (ptr--) - (cr - s));
3162 debug_printf("SMTP>> %s", s);
3166 /* Reset the protocol and the state, abandoning any previous message. */
3168 received_protocol = (esmtp?
3170 ((sender_host_authenticated != NULL)? pauthed : 0) +
3171 ((tls_active >= 0)? pcrpted : 0)]
3173 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
3175 ((sender_host_address != NULL)? pnlocal : 0);
3177 smtp_reset(reset_point);
3179 break; /* HELO/EHLO */
3182 /* The MAIL command requires an address as an operand. All we do
3183 here is to parse it for syntactic correctness. The form "<>" is
3184 a special case which converts into an empty string. The start/end
3185 pointers in the original are not used further for this address, as
3186 it is the canonical extracted address which is all that is kept. */
3190 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3191 was_rej_mail = TRUE; /* Reset if accepted */
3193 if (helo_required && !helo_seen)
3195 smtp_printf("503 HELO or EHLO required\r\n");
3196 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3197 "HELO/EHLO given", host_and_ident(FALSE));
3201 if (sender_address != NULL)
3203 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3204 US"sender already given");
3208 if (smtp_cmd_data[0] == 0)
3210 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3211 US"MAIL must have an address operand");
3215 /* Check to see if the limit for messages per connection would be
3216 exceeded by accepting further messages. */
3218 if (smtp_accept_max_per_connection > 0 &&
3219 smtp_mailcmd_count > smtp_accept_max_per_connection)
3221 smtp_printf("421 too many messages in this connection\r\n");
3222 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3223 "messages in one connection", host_and_ident(TRUE));
3227 /* Reset for start of message - even if this is going to fail, we
3228 obviously need to throw away any previous data. */
3230 smtp_reset(reset_point);
3232 sender_data = recipient_data = NULL;
3234 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3238 uschar *name, *value, *end;
3239 unsigned long int size;
3241 if (!extract_option(&name, &value)) break;
3243 /* Handle SIZE= by reading the value. We don't do the check till later,
3244 in order to be able to log the sender address on failure. */
3246 if (strcmpic(name, US"SIZE") == 0 &&
3247 ((size = Ustrtoul(value, &end, 10)), *end == 0))
3249 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3251 message_size = (int)size;
3254 /* If this session was initiated with EHLO and accept_8bitmime is set,
3255 Exim will have indicated that it supports the BODY=8BITMIME option. In
3256 fact, it does not support this according to the RFCs, in that it does not
3257 take any special action for forwarding messages containing 8-bit
3258 characters. That is why accept_8bitmime is not the default setting, but
3259 some sites want the action that is provided. We recognize both "8BITMIME"
3260 and "7BIT" as body types, but take no action. */
3262 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
3263 (strcmpic(value, US"8BITMIME") == 0 ||
3264 strcmpic(value, US"7BIT") == 0)) {}
3266 /* Handle the AUTH extension. If the value given is not "<>" and either
3267 the ACL says "yes" or there is no ACL but the sending host is
3268 authenticated, we set it up as the authenticated sender. However, if the
3269 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3270 the condition is met. The value of AUTH is an xtext, which means that +,
3271 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3274 else if (strcmpic(name, US"AUTH") == 0)
3276 if (Ustrcmp(value, "<>") != 0)
3281 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3283 /* Put back terminator overrides for error message */
3286 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3287 US"invalid data for AUTH");
3291 if (acl_smtp_mailauth == NULL)
3293 ignore_msg = US"client not authenticated";
3294 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3298 ignore_msg = US"rejected by ACL";
3299 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3300 &user_msg, &log_msg);
3306 if (authenticated_by == NULL ||
3307 authenticated_by->mail_auth_condition == NULL ||
3308 expand_check_condition(authenticated_by->mail_auth_condition,
3309 authenticated_by->name, US"authenticator"))
3310 break; /* Accept the AUTH */
3312 ignore_msg = US"server_mail_auth_condition failed";
3313 if (authenticated_id != NULL)
3314 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3315 ignore_msg, authenticated_id);
3320 authenticated_sender = NULL;
3321 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3322 value, host_and_ident(TRUE), ignore_msg);
3325 /* Should only get DEFER or ERROR here. Put back terminator
3326 overrides for error message */
3331 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3338 /* Unknown option. Stick back the terminator characters and break
3339 the loop. An error for a malformed address will occur. */
3349 /* If we have passed the threshold for rate limiting, apply the current
3350 delay, and update it for next time, provided this is a limited host. */
3352 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3353 verify_check_host(&smtp_ratelimit_hosts) == OK)
3355 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3356 smtp_delay_mail/1000.0);
3357 millisleep((int)smtp_delay_mail);
3358 smtp_delay_mail *= smtp_rlm_factor;
3359 if (smtp_delay_mail > (double)smtp_rlm_limit)
3360 smtp_delay_mail = (double)smtp_rlm_limit;
3363 /* Now extract the address, first applying any SMTP-time rewriting. The
3364 TRUE flag allows "<>" as a sender address. */
3366 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3367 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3368 global_rewrite_rules) : smtp_cmd_data;
3370 /* rfc821_domains = TRUE; << no longer needed */
3372 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3374 /* rfc821_domains = FALSE; << no longer needed */
3376 if (raw_sender == NULL)
3378 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3382 sender_address = raw_sender;
3384 /* If there is a configured size limit for mail, check that this message
3385 doesn't exceed it. The check is postponed to this point so that the sender
3388 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3390 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3391 log_write(L_size_reject,
3392 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3393 "message too big: size%s=%d max=%d",
3395 host_and_ident(TRUE),
3396 (message_size == INT_MAX)? ">" : "",
3398 thismessage_size_limit);
3399 sender_address = NULL;
3403 /* Check there is enough space on the disk unless configured not to.
3404 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3405 plus the current message - i.e. we accept the message only if it won't
3406 reduce the space below the threshold. Add 5000 to the size to allow for
3407 overheads such as the Received: line and storing of recipients, etc.
3408 By putting the check here, even when SIZE is not given, it allow VRFY
3409 and EXPN etc. to be used when space is short. */
3411 if (!receive_check_fs(
3412 (smtp_check_spool_space && message_size >= 0)?
3413 message_size + 5000 : 0))
3415 smtp_printf("452 Space shortage, please try later\r\n");
3416 sender_address = NULL;
3420 /* If sender_address is unqualified, reject it, unless this is a locally
3421 generated message, or the sending host or net is permitted to send
3422 unqualified addresses - typically local machines behaving as MUAs -
3423 in which case just qualify the address. The flag is set above at the start
3424 of the SMTP connection. */
3426 if (sender_domain == 0 && sender_address[0] != 0)
3428 if (allow_unqualified_sender)
3430 sender_domain = Ustrlen(sender_address) + 1;
3431 sender_address = rewrite_address_qualify(sender_address, FALSE);
3432 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3437 smtp_printf("501 %s: sender address must contain a domain\r\n",
3439 log_write(L_smtp_syntax_error,
3440 LOG_MAIN|LOG_REJECT,
3441 "unqualified sender rejected: <%s> %s%s",
3443 host_and_ident(TRUE),
3445 sender_address = NULL;
3450 /* Apply an ACL check if one is defined, before responding. Afterwards,
3451 when pipelining is not advertised, do another sync check in case the ACL
3452 delayed and the client started sending in the meantime. */
3454 if (acl_smtp_mail == NULL) rc = OK; else
3456 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3457 if (rc == OK && !pipelining_advertised && !check_sync())
3461 if (rc == OK || rc == DISCARD)
3463 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3464 else smtp_user_msg(US"250", user_msg);
3465 smtp_delay_rcpt = smtp_rlr_base;
3466 recipients_discarded = (rc == DISCARD);
3467 was_rej_mail = FALSE;
3471 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3472 sender_address = NULL;
3477 /* The RCPT command requires an address as an operand. There may be any
3478 number of RCPT commands, specifying multiple recipients. We build them all
3479 into a data structure. The start/end values given by parse_extract_address
3480 are not used, as we keep only the extracted address. */
3485 was_rcpt = rcpt_in_progress = TRUE;
3487 /* There must be a sender address; if the sender was rejected and
3488 pipelining was advertised, we assume the client was pipelining, and do not
3489 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3490 get the same treatment. */
3492 if (sender_address == NULL)
3494 if (pipelining_advertised && last_was_rej_mail)
3496 smtp_printf("503 sender not yet given\r\n");
3497 was_rej_mail = TRUE;
3501 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3502 US"sender not yet given");
3503 was_rcpt = FALSE; /* Not a valid RCPT */
3509 /* Check for an operand */
3511 if (smtp_cmd_data[0] == 0)
3513 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3514 US"RCPT must have an address operand");
3519 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3520 as a recipient address */
3522 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3523 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3524 global_rewrite_rules) : smtp_cmd_data;
3526 /* rfc821_domains = TRUE; << no longer needed */
3527 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3528 &recipient_domain, FALSE);
3529 /* rfc821_domains = FALSE; << no longer needed */
3531 if (recipient == NULL)
3533 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3538 /* If the recipient address is unqualified, reject it, unless this is a
3539 locally generated message. However, unqualified addresses are permitted
3540 from a configured list of hosts and nets - typically when behaving as
3541 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3542 really. The flag is set at the start of the SMTP connection.
3544 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3545 assumed this meant "reserved local part", but the revision of RFC 821 and
3546 friends now makes it absolutely clear that it means *mailbox*. Consequently
3547 we must always qualify this address, regardless. */
3549 if (recipient_domain == 0)
3551 if (allow_unqualified_recipient ||
3552 strcmpic(recipient, US"postmaster") == 0)
3554 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3556 recipient_domain = Ustrlen(recipient) + 1;
3557 recipient = rewrite_address_qualify(recipient, TRUE);
3562 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3564 log_write(L_smtp_syntax_error,
3565 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3566 "<%s> %s%s", recipient, host_and_ident(TRUE),
3572 /* Check maximum allowed */
3574 if (rcpt_count > recipients_max && recipients_max > 0)
3576 if (recipients_max_reject)
3579 smtp_printf("552 too many recipients\r\n");
3581 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3582 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3587 smtp_printf("452 too many recipients\r\n");
3589 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3590 "temporarily rejected: sender=<%s> %s", sender_address,
3591 host_and_ident(TRUE));
3598 /* If we have passed the threshold for rate limiting, apply the current
3599 delay, and update it for next time, provided this is a limited host. */
3601 if (rcpt_count > smtp_rlr_threshold &&
3602 verify_check_host(&smtp_ratelimit_hosts) == OK)
3604 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3605 smtp_delay_rcpt/1000.0);
3606 millisleep((int)smtp_delay_rcpt);
3607 smtp_delay_rcpt *= smtp_rlr_factor;
3608 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3609 smtp_delay_rcpt = (double)smtp_rlr_limit;
3612 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3613 for them. Otherwise, check the access control list for this recipient. As
3614 there may be a delay in this, re-check for a synchronization error
3615 afterwards, unless pipelining was advertised. */
3617 if (recipients_discarded) rc = DISCARD; else
3619 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
3621 if (rc == OK && !pipelining_advertised && !check_sync())
3625 /* The ACL was happy */
3629 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3630 else smtp_user_msg(US"250", user_msg);
3631 receive_add_recipient(recipient, -1);
3634 /* The recipient was discarded */
3636 else if (rc == DISCARD)
3638 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3639 else smtp_user_msg(US"250", user_msg);
3642 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3643 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3644 (sender_address_unrewritten != NULL)?
3645 sender_address_unrewritten : sender_address,
3646 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3647 (log_msg == NULL)? US"" : US": ",
3648 (log_msg == NULL)? US"" : log_msg);
3651 /* Either the ACL failed the address, or it was deferred. */
3655 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3656 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3661 /* The DATA command is legal only if it follows successful MAIL FROM
3662 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3663 not counted as a protocol error if it follows RCPT (which must have been
3664 rejected if there are no recipients.) This function is complete when a
3665 valid DATA command is encountered.
3667 Note concerning the code used: RFC 2821 says this:
3669 - If there was no MAIL, or no RCPT, command, or all such commands
3670 were rejected, the server MAY return a "command out of sequence"
3671 (503) or "no valid recipients" (554) reply in response to the
3674 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3675 because it is the same whether pipelining is in use or not.
3677 If all the RCPT commands that precede DATA provoked the same error message
3678 (often indicating some kind of system error), it is helpful to include it
3679 with the DATA rejection (an idea suggested by Tony Finch). */
3683 if (!discarded && recipients_count <= 0)
3685 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
3687 uschar *code = US"503";
3688 int len = Ustrlen(rcpt_smtp_response);
3689 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
3691 /* Responses from smtp_printf() will have \r\n on the end */
3692 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
3693 rcpt_smtp_response[len-2] = 0;
3694 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
3696 if (pipelining_advertised && last_was_rcpt)
3697 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
3699 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3700 US"valid RCPT command must precede DATA");
3704 if (toomany && recipients_max_reject)
3706 sender_address = NULL; /* This will allow a new MAIL without RSET */
3707 sender_address_unrewritten = NULL;
3708 smtp_printf("554 Too many recipients\r\n");
3712 /* If there is an ACL, re-check the synchronization afterwards, since the
3713 ACL may have delayed. */
3715 if (acl_smtp_predata == NULL) rc = OK; else
3717 enable_dollar_recipients = TRUE;
3718 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3720 enable_dollar_recipients = FALSE;
3721 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
3726 if (user_msg == NULL)
3727 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3728 else smtp_user_msg(US"354", user_msg);
3730 message_ended = END_NOTENDED; /* Indicate in middle of data */
3733 /* Either the ACL failed the address, or it was deferred. */
3736 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3742 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3744 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3750 /* rfc821_domains = TRUE; << no longer needed */
3751 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
3752 &recipient_domain, FALSE);
3753 /* rfc821_domains = FALSE; << no longer needed */
3755 if (address == NULL)
3756 s = string_sprintf("501 %s", errmess);
3759 address_item *addr = deliver_make_addr(address, FALSE);
3760 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3761 -1, -1, NULL, NULL, NULL))
3764 s = string_sprintf("250 <%s> is deliverable", address);
3768 s = (addr->user_message != NULL)?
3769 string_sprintf("451 <%s> %s", address, addr->user_message) :
3770 string_sprintf("451 Cannot resolve <%s> at this time", address);
3774 s = (addr->user_message != NULL)?
3775 string_sprintf("550 <%s> %s", address, addr->user_message) :
3776 string_sprintf("550 <%s> is not deliverable", address);
3777 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3778 smtp_cmd_argument, host_and_ident(TRUE));
3783 smtp_printf("%s\r\n", s);
3790 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3792 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3795 BOOL save_log_testing_mode = log_testing_mode;
3796 address_test_mode = log_testing_mode = TRUE;
3797 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
3798 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3800 address_test_mode = FALSE;
3801 log_testing_mode = save_log_testing_mode; /* true for -bh */
3810 if (!tls_advertised)
3812 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3813 US"STARTTLS command used when not advertised");
3817 /* Apply an ACL check if one is defined */
3819 if (acl_smtp_starttls != NULL)
3821 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3825 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3830 /* RFC 2487 is not clear on when this command may be sent, though it
3831 does state that all information previously obtained from the client
3832 must be discarded if a TLS session is started. It seems reasonble to
3833 do an implied RSET when STARTTLS is received. */
3835 incomplete_transaction_log(US"STARTTLS");
3836 smtp_reset(reset_point);
3838 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3840 /* Attempt to start up a TLS session, and if successful, discard all
3841 knowledge that was obtained previously. At least, that's what the RFC says,
3842 and that's what happens by default. However, in order to work round YAEB,
3843 there is an option to remember the esmtp state. Sigh.
3845 We must allow for an extra EHLO command and an extra AUTH command after
3846 STARTTLS that don't add to the nonmail command count. */
3848 if ((rc = tls_server_start(tls_require_ciphers, gnutls_require_mac,
3849 gnutls_require_kx, gnutls_require_proto)) == OK)
3851 if (!tls_remember_esmtp)
3852 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3853 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3854 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3855 if (sender_helo_name != NULL)
3857 store_free(sender_helo_name);
3858 sender_helo_name = NULL;
3859 host_build_sender_fullhost(); /* Rebuild */
3860 set_process_info("handling incoming TLS connection from %s",
3861 host_and_ident(FALSE));
3863 received_protocol = (esmtp?
3864 protocols[pextend + pcrpted +
3865 ((sender_host_authenticated != NULL)? pauthed : 0)]
3867 protocols[pnormal + pcrpted])
3869 ((sender_host_address != NULL)? pnlocal : 0);
3871 sender_host_authenticated = NULL;
3872 authenticated_id = NULL;
3873 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3874 DEBUG(D_tls) debug_printf("TLS active\n");
3875 break; /* Successful STARTTLS */
3878 /* Some local configuration problem was discovered before actually trying
3879 to do a TLS handshake; give a temporary error. */
3881 else if (rc == DEFER)
3883 smtp_printf("454 TLS currently unavailable\r\n");
3887 /* Hard failure. Reject everything except QUIT or closed connection. One
3888 cause for failure is a nested STARTTLS, in which case tls_active remains
3889 set, but we must still reject all incoming commands. */
3891 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3894 switch(smtp_read_command(FALSE))
3897 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3898 smtp_get_connection_info());
3899 smtp_notquit_exit(US"tls-failed", NULL, NULL);
3903 /* It is perhaps arguable as to which exit ACL should be called here,
3904 but as it is probably a situtation that almost never arises, it
3905 probably doesn't matter. We choose to call the real QUIT ACL, which in
3906 some sense is perhaps "right". */
3910 if (acl_smtp_quit != NULL)
3912 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
3915 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3918 if (user_msg == NULL)
3919 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3921 smtp_respond(US"221", 3, TRUE, user_msg);
3922 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3923 smtp_get_connection_info());
3928 smtp_printf("554 Security failure\r\n");
3937 /* The ACL for QUIT is provided for gathering statistical information or
3938 similar; it does not affect the response code, but it can supply a custom
3943 incomplete_transaction_log(US"QUIT");
3944 if (acl_smtp_quit != NULL)
3946 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
3948 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3951 if (user_msg == NULL)
3952 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3954 smtp_respond(US"221", 3, TRUE, user_msg);
3961 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3962 smtp_get_connection_info());
3968 incomplete_transaction_log(US"RSET");
3969 smtp_reset(reset_point);
3971 smtp_printf("250 Reset OK\r\n");
3972 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3978 smtp_printf("250 OK\r\n");
3982 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
3983 used, a check will be done for permitted hosts. Show STARTTLS only if not
3984 already in a TLS session and if it would be advertised in the EHLO
3989 smtp_printf("214-Commands supported:\r\n");
3993 Ustrcat(buffer, " AUTH");
3995 if (tls_active < 0 &&
3996 verify_check_host(&tls_advertise_hosts) != FAIL)
3997 Ustrcat(buffer, " STARTTLS");
3999 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
4000 Ustrcat(buffer, " NOOP QUIT RSET HELP");
4001 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4002 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4003 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4004 smtp_printf("214%s\r\n", buffer);
4010 incomplete_transaction_log(US"connection lost");
4011 smtp_notquit_exit(US"connection-lost", US"421",
4012 US"%s lost input connection", smtp_active_hostname);
4014 /* Don't log by default unless in the middle of a message, as some mailers
4015 just drop the call rather than sending QUIT, and it clutters up the logs.
4018 if (sender_address != NULL || recipients_count > 0)
4019 log_write(L_lost_incoming_connection,
4021 "unexpected %s while reading SMTP command from %s%s",
4022 sender_host_unknown? "EOF" : "disconnection",
4023 host_and_ident(FALSE), smtp_read_error);
4025 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4026 smtp_get_connection_info(), smtp_read_error);
4034 if (sender_address != NULL)
4036 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4037 US"ETRN is not permitted inside a transaction");
4041 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4042 host_and_ident(FALSE));
4044 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4047 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4051 /* Compute the serialization key for this command. */
4053 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4055 /* If a command has been specified for running as a result of ETRN, we
4056 permit any argument to ETRN. If not, only the # standard form is permitted,
4057 since that is strictly the only kind of ETRN that can be implemented
4058 according to the RFC. */
4060 if (smtp_etrn_command != NULL)
4064 etrn_command = smtp_etrn_command;
4065 deliver_domain = smtp_cmd_data;
4066 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4067 US"ETRN processing", &error);
4068 deliver_domain = NULL;
4071 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4073 smtp_printf("458 Internal failure\r\n");
4078 /* Else set up to call Exim with the -R option. */
4082 if (*smtp_cmd_data++ != '#')
4084 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4085 US"argument must begin with #");
4088 etrn_command = US"exim -R";
4089 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4093 /* If we are host-testing, don't actually do anything. */
4099 debug_printf("ETRN command is: %s\n", etrn_command);
4100 debug_printf("ETRN command execution skipped\n");
4102 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4103 else smtp_user_msg(US"250", user_msg);
4108 /* If ETRN queue runs are to be serialized, check the database to
4109 ensure one isn't already running. */
4111 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4113 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4117 /* Fork a child process and run the command. We don't want to have to
4118 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4119 forking. It should be set that way anyway for external incoming SMTP,
4120 but we save and restore to be tidy. If serialization is required, we
4121 actually run the command in yet another process, so we can wait for it
4122 to complete and then remove the serialization lock. */
4124 oldsignal = signal(SIGCHLD, SIG_IGN);
4126 if ((pid = fork()) == 0)
4128 smtp_input = FALSE; /* This process is not associated with the */
4129 (void)fclose(smtp_in); /* SMTP call any more. */
4130 (void)fclose(smtp_out);
4132 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
4134 /* If not serializing, do the exec right away. Otherwise, fork down
4135 into another process. */
4137 if (!smtp_etrn_serialize || (pid = fork()) == 0)
4139 DEBUG(D_exec) debug_print_argv(argv);
4140 exim_nullstd(); /* Ensure std{in,out,err} exist */
4141 execv(CS argv[0], (char *const *)argv);
4142 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
4143 etrn_command, strerror(errno));
4144 _exit(EXIT_FAILURE); /* paranoia */
4147 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4148 is, we are in the first subprocess, after forking again. All we can do
4149 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4150 complete, before removing the serialization. */
4153 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4154 "failed: %s", strerror(errno));
4158 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4160 (void)wait(&status);
4161 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4165 enq_end(etrn_serialize_key);
4166 _exit(EXIT_SUCCESS);
4169 /* Back in the top level SMTP process. Check that we started a subprocess
4170 and restore the signal state. */
4174 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4176 smtp_printf("458 Unable to fork process\r\n");
4177 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4181 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4182 else smtp_user_msg(US"250", user_msg);
4185 signal(SIGCHLD, oldsignal);
4190 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4191 US"unexpected argument data");
4195 /* This currently happens only for NULLs, but could be extended. */
4198 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
4199 US"NULL character(s) present (shown as '?')");
4200 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
4206 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
4207 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
4208 c = smtp_inend - smtp_inptr;
4209 if (c > 150) c = 150;
4211 incomplete_transaction_log(US"sync failure");
4212 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
4213 "(next input sent too soon: pipelining was%s advertised): "
4214 "rejected \"%s\" %s next input=\"%s\"",
4215 pipelining_advertised? "" : " not",
4216 smtp_cmd_buffer, host_and_ident(TRUE),
4217 string_printing(smtp_inptr));
4218 smtp_notquit_exit(US"synchronization-error", US"554",
4219 US"SMTP synchronization error");
4220 done = 1; /* Pretend eof - drops connection */
4224 case TOO_MANY_NONMAIL_CMD:
4225 s = smtp_cmd_buffer;
4226 while (*s != 0 && !isspace(*s)) s++;
4227 incomplete_transaction_log(US"too many non-mail commands");
4228 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4229 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
4230 s - smtp_cmd_buffer, smtp_cmd_buffer);
4231 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
4232 done = 1; /* Pretend eof - drops connection */
4237 if (unknown_command_count++ >= smtp_max_unknown_commands)
4239 log_write(L_smtp_syntax_error, LOG_MAIN,
4240 "SMTP syntax error in \"%s\" %s %s",
4241 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
4242 US"unrecognized command");
4243 incomplete_transaction_log(US"unrecognized command");
4244 smtp_notquit_exit(US"bad-commands", US"500",
4245 US"Too many unrecognized commands");
4247 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4248 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
4252 done = synprot_error(L_smtp_syntax_error, 500, NULL,
4253 US"unrecognized command");
4257 /* This label is used by goto's inside loops that want to break out to
4258 the end of the command-processing loop. */
4261 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
4262 last_was_rcpt = was_rcpt; /* protocol error handling */
4266 return done - 2; /* Convert yield values */
4269 /* End of smtp_in.c */
git://git.exim.org / users / heiko / exim.git / blob