1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.67 2010/06/12 15:21:26 jetmore Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2009 */
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;
34 uschar *tcp_wrappers_name;
38 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
39 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
40 commands that accept arguments, and this in particular applies to AUTH, where
41 the data can be quite long. */
43 #define smtp_cmd_buffer_size 2048
45 /* Size of buffer for reading SMTP incoming packets */
47 #define in_buffer_size 8192
49 /* Structure for SMTP command list */
56 short int is_mail_cmd;
59 /* Codes for identifying commands. We order them so that those that come first
60 are those for which synchronization is always required. Checking this can help
64 /* These commands are required to be synchronized, i.e. to be the last in a
65 block of commands when pipelining. */
67 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
68 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
69 ETRN_CMD, /* This by analogy with TURN from the RFC */
70 STARTTLS_CMD, /* Required by the STARTTLS RFC */
72 /* This is a dummy to identify the non-sync commands when pipelining */
74 NON_SYNC_CMD_PIPELINING,
76 /* These commands need not be synchronized when pipelining */
78 MAIL_CMD, RCPT_CMD, RSET_CMD,
80 /* This is a dummy to identify the non-sync commands when not pipelining */
82 NON_SYNC_CMD_NON_PIPELINING,
84 /* I have been unable to find a statement about the use of pipelining
85 with AUTH, so to be on the safe side it is here, though I kind of feel
86 it should be up there with the synchronized commands. */
90 /* I'm not sure about these, but I don't think they matter. */
94 /* These are specials that don't correspond to actual commands */
96 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
97 TOO_MANY_NONMAIL_CMD };
100 /* This is a convenience macro for adding the identity of an SMTP command
101 to the circular buffer that holds a list of the last n received. */
104 smtp_connection_had[smtp_ch_index++] = n; \
105 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
108 /*************************************************
109 * Local static variables *
110 *************************************************/
112 static auth_instance *authenticated_by;
113 static BOOL auth_advertised;
115 static BOOL tls_advertised;
118 static BOOL helo_required = FALSE;
119 static BOOL helo_verify = FALSE;
120 static BOOL helo_seen;
121 static BOOL helo_accept_junk;
122 static BOOL count_nonmail;
123 static BOOL pipelining_advertised;
124 static BOOL rcpt_smtp_response_same;
125 static BOOL rcpt_in_progress;
126 static int nonmail_command_count;
127 static BOOL smtp_exit_function_called = 0;
128 static int synprot_error_count;
129 static int unknown_command_count;
130 static int sync_cmd_limit;
131 static int smtp_write_error = 0;
133 static uschar *rcpt_smtp_response;
134 static uschar *smtp_data_buffer;
135 static uschar *smtp_cmd_data;
137 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
138 final fields of all except AUTH are forced TRUE at the start of a new message
139 setup, to allow one of each between messages that is not counted as a nonmail
140 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
141 allow a new EHLO after starting up TLS.
143 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
144 counted. However, the flag is changed when AUTH is received, so that multiple
145 failing AUTHs will eventually hit the limit. After a successful AUTH, another
146 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
147 forced TRUE, to allow for the re-authentication that can happen at that point.
149 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
150 count of non-mail commands and possibly provoke an error. */
152 static smtp_cmd_list cmd_list[] = {
153 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
154 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
155 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
156 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
158 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
161 /* If you change anything above here, also fix the definitions below. */
163 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
164 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
165 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
166 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
167 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
168 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
169 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
170 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
171 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
174 static smtp_cmd_list *cmd_list_end =
175 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
177 #define CMD_LIST_RSET 0
178 #define CMD_LIST_HELO 1
179 #define CMD_LIST_EHLO 2
180 #define CMD_LIST_AUTH 3
181 #define CMD_LIST_STARTTLS 4
183 /* This list of names is used for performing the smtp_no_mail logging action.
184 It must be kept in step with the SCH_xxx enumerations. */
186 static uschar *smtp_names[] =
188 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
189 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
192 static uschar *protocols[] = {
193 US"local-smtp", /* HELO */
194 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
195 US"local-esmtp", /* EHLO */
196 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
197 US"local-esmtpa", /* EHLO->AUTH */
198 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
203 #define pcrpted 1 /* added to pextend or pnormal */
204 #define pauthed 2 /* added to pextend */
205 #define pnlocal 6 /* offset to remove "local" */
207 /* When reading SMTP from a remote host, we have to use our own versions of the
208 C input-reading functions, in order to be able to flush the SMTP output only
209 when about to read more data from the socket. This is the only way to get
210 optimal performance when the client is using pipelining. Flushing for every
211 command causes a separate packet and reply packet each time; saving all the
212 responses up (when pipelining) combines them into one packet and one response.
214 For simplicity, these functions are used for *all* SMTP input, not only when
215 receiving over a socket. However, after setting up a secure socket (SSL), input
216 is read via the OpenSSL library, and another set of functions is used instead
219 These functions are set in the receive_getc etc. variables and called with the
220 same interface as the C functions. However, since there can only ever be
221 one incoming SMTP call, we just use a single buffer and flags. There is no need
222 to implement a complicated private FILE-like structure.*/
224 static uschar *smtp_inbuffer;
225 static uschar *smtp_inptr;
226 static uschar *smtp_inend;
227 static int smtp_had_eof;
228 static int smtp_had_error;
231 /*************************************************
232 * SMTP version of getc() *
233 *************************************************/
235 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
236 it flushes the output, and refills the buffer, with a timeout. The signal
237 handler is set appropriately by the calling function. This function is not used
238 after a connection has negotated itself into an TLS/SSL state.
241 Returns: the next character or EOF
247 if (smtp_inptr >= smtp_inend)
251 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
252 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
257 /* Must put the error text in fixed store, because this might be during
258 header reading, where it releases unused store above the header. */
261 smtp_had_error = save_errno;
262 smtp_read_error = string_copy_malloc(
263 string_sprintf(" (error: %s)", strerror(save_errno)));
265 else smtp_had_eof = 1;
269 dkim_exim_verify_feed(smtp_inbuffer, rc);
271 smtp_inend = smtp_inbuffer + rc;
272 smtp_inptr = smtp_inbuffer;
274 return *smtp_inptr++;
279 /*************************************************
280 * SMTP version of ungetc() *
281 *************************************************/
283 /* Puts a character back in the input buffer. Only ever
289 Returns: the character
295 *(--smtp_inptr) = ch;
302 /*************************************************
303 * SMTP version of feof() *
304 *************************************************/
306 /* Tests for a previous EOF
309 Returns: non-zero if the eof flag is set
321 /*************************************************
322 * SMTP version of ferror() *
323 *************************************************/
325 /* Tests for a previous read error, and returns with errno
326 restored to what it was when the error was detected.
329 Returns: non-zero if the error flag is set
335 errno = smtp_had_error;
336 return smtp_had_error;
341 /*************************************************
342 * Test for characters in the SMTP buffer *
343 *************************************************/
345 /* Used at the end of a message
354 return smtp_inptr < smtp_inend;
359 /*************************************************
360 * Write formatted string to SMTP channel *
361 *************************************************/
363 /* This is a separate function so that we don't have to repeat everything for
364 TLS support or debugging. It is global so that the daemon and the
365 authentication functions can use it. It does not return any error indication,
366 because major problems such as dropped connections won't show up till an output
367 flush for non-TLS connections. The smtp_fflush() function is available for
368 checking that: for convenience, TLS output errors are remembered here so that
369 they are also picked up later by smtp_fflush().
373 ... optional arguments
379 smtp_printf(const char *format, ...)
383 va_start(ap, format);
384 smtp_vprintf(format, ap);
388 /* This is split off so that verify.c:respond_printf() can, in effect, call
389 smtp_printf(), bearing in mind that in C a vararg function can't directly
390 call another vararg function, only a function which accepts a va_list. */
393 smtp_vprintf(const char *format, va_list ap)
397 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
401 void *reset_point = store_get(0);
402 uschar *msg_copy, *cr, *end;
403 msg_copy = string_copy(big_buffer);
404 end = msg_copy + Ustrlen(msg_copy);
405 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
406 memmove(cr, cr + 1, (end--) - cr);
407 debug_printf("SMTP>> %s", msg_copy);
408 store_reset(reset_point);
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 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
1696 if (tcp_wrappers_name == NULL)
1698 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
1699 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
1700 expand_string_message);
1702 if (!hosts_ctl(tcp_wrappers_name,
1703 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1704 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1705 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1707 if (errno == 0 || errno == ENOENT)
1709 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1710 log_write(L_connection_reject,
1711 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1712 "(tcp wrappers)", host_and_ident(FALSE));
1713 smtp_printf("554 SMTP service not available\r\n");
1717 int save_errno = errno;
1718 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1719 "errno value %d\n", save_errno);
1720 log_write(L_connection_reject,
1721 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1722 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1723 smtp_printf("451 Temporary local problem - please try later\r\n");
1729 /* Check for reserved slots. The value of smtp_accept_count has already been
1730 incremented to include this process. */
1732 if (smtp_accept_max > 0 &&
1733 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
1735 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1737 log_write(L_connection_reject,
1738 LOG_MAIN, "temporarily refused connection from %s: not in "
1739 "reserve list: connected=%d max=%d reserve=%d%s",
1740 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
1741 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1742 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1743 "please try again later\r\n", smtp_active_hostname);
1746 reserved_host = TRUE;
1749 /* If a load level above which only messages from reserved hosts are
1750 accepted is set, check the load. For incoming calls via the daemon, the
1751 check is done in the superior process if there are no reserved hosts, to
1752 save a fork. In all cases, the load average will already be available
1753 in a global variable at this point. */
1755 if (smtp_load_reserve >= 0 &&
1756 load_average > smtp_load_reserve &&
1758 verify_check_host(&smtp_reserve_hosts) != OK)
1760 log_write(L_connection_reject,
1761 LOG_MAIN, "temporarily refused connection from %s: not in "
1762 "reserve list and load average = %.2f", host_and_ident(FALSE),
1763 (double)load_average/1000.0);
1764 smtp_printf("421 %s: Too much load; please try again later\r\n",
1765 smtp_active_hostname);
1769 /* Determine whether unqualified senders or recipients are permitted
1770 for this host. Unfortunately, we have to do this every time, in order to
1771 set the flags so that they can be inspected when considering qualifying
1772 addresses in the headers. For a site that permits no qualification, this
1773 won't take long, however. */
1775 allow_unqualified_sender =
1776 verify_check_host(&sender_unqualified_hosts) == OK;
1778 allow_unqualified_recipient =
1779 verify_check_host(&recipient_unqualified_hosts) == OK;
1781 /* Determine whether HELO/EHLO is required for this host. The requirement
1782 can be hard or soft. */
1784 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1786 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1788 /* Determine whether this hosts is permitted to send syntactic junk
1789 after a HELO or EHLO command. */
1791 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1794 /* For batch SMTP input we are now done. */
1796 if (smtp_batched_input) return TRUE;
1798 /* Run the ACL if it exists */
1801 if (acl_smtp_connect != NULL)
1804 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1808 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1813 /* Output the initial message for a two-way SMTP connection. It may contain
1814 newlines, which then cause a multi-line response to be given. */
1816 code = US"220"; /* Default status code */
1817 esc = US""; /* Default extended status code */
1818 esclen = 0; /* Length of esc */
1820 if (user_msg == NULL)
1822 s = expand_string(smtp_banner);
1824 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1825 "failed: %s", smtp_banner, expand_string_message);
1831 smtp_message_code(&code, &codelen, &s, NULL);
1835 esclen = codelen - 4;
1839 /* Remove any terminating newlines; might as well remove trailing space too */
1842 while (p > s && isspace(p[-1])) p--;
1845 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1846 is all contained in a single IP packet. The original code wrote out the
1847 greeting using several calls to fprint/fputc, and on busy servers this could
1848 cause it to be split over more than one packet - which caused CC:Mail to fall
1849 over when it got the second part of the greeting after sending its first
1850 command. Sigh. To try to avoid this, build the complete greeting message
1851 first, and output it in one fell swoop. This gives a better chance of it
1852 ending up as a single packet. */
1854 ss = store_get(size);
1858 do /* At least once, in case we have an empty string */
1861 uschar *linebreak = Ustrchr(p, '\n');
1862 ss = string_cat(ss, &size, &ptr, code, 3);
1863 if (linebreak == NULL)
1866 ss = string_cat(ss, &size, &ptr, US" ", 1);
1870 len = linebreak - p;
1871 ss = string_cat(ss, &size, &ptr, US"-", 1);
1873 ss = string_cat(ss, &size, &ptr, esc, esclen);
1874 ss = string_cat(ss, &size, &ptr, p, len);
1875 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1877 if (linebreak != NULL) p++;
1881 ss[ptr] = 0; /* string_cat leaves room for this */
1883 /* Before we write the banner, check that there is no input pending, unless
1884 this synchronisation check is disabled. */
1888 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1889 "synchronization error (input sent without waiting for greeting): "
1890 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1891 string_printing(smtp_inptr));
1892 smtp_printf("554 SMTP synchronization error\r\n");
1896 /* Now output the banner */
1898 smtp_printf("%s", ss);
1906 /*************************************************
1907 * Handle SMTP syntax and protocol errors *
1908 *************************************************/
1910 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1911 to do so. Then transmit the error response. The return value depends on the
1912 number of syntax and protocol errors in this SMTP session.
1915 type error type, given as a log flag bit
1916 code response code; <= 0 means don't send a response
1917 data data to reflect in the response (can be NULL)
1918 errmess the error message
1920 Returns: -1 limit of syntax/protocol errors NOT exceeded
1921 +1 limit of syntax/protocol errors IS exceeded
1923 These values fit in with the values of the "done" variable in the main
1924 processing loop in smtp_setup_msg(). */
1927 synprot_error(int type, int code, uschar *data, uschar *errmess)
1931 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1932 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1933 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1935 if (++synprot_error_count > smtp_max_synprot_errors)
1938 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1939 "syntax or protocol errors (last command was \"%s\")",
1940 host_and_ident(FALSE), smtp_cmd_buffer);
1945 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1946 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1948 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1957 /*************************************************
1958 * Log incomplete transactions *
1959 *************************************************/
1961 /* This function is called after a transaction has been aborted by RSET, QUIT,
1962 connection drops or other errors. It logs the envelope information received
1963 so far in order to preserve address verification attempts.
1965 Argument: string to indicate what aborted the transaction
1970 incomplete_transaction_log(uschar *what)
1972 if (sender_address == NULL || /* No transaction in progress */
1973 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1976 /* Build list of recipients for logging */
1978 if (recipients_count > 0)
1981 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1982 for (i = 0; i < recipients_count; i++)
1983 raw_recipients[i] = recipients_list[i].address;
1984 raw_recipients_count = recipients_count;
1987 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1988 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1994 /*************************************************
1995 * Send SMTP response, possibly multiline *
1996 *************************************************/
1998 /* There are, it seems, broken clients out there that cannot handle multiline
1999 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2000 output nothing for non-final calls, and only the first line for anything else.
2003 code SMTP code, may involve extended status codes
2004 codelen length of smtp code; if > 4 there's an ESC
2005 final FALSE if the last line isn't the final line
2006 msg message text, possibly containing newlines
2012 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2017 if (!final && no_multiline_responses) return;
2022 esclen = codelen - 4;
2025 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2026 have had the same. Note: this code is also present in smtp_printf(). It would
2027 be tidier to have it only in one place, but when it was added, it was easier to
2028 do it that way, so as not to have to mess with the code for the RCPT command,
2029 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2031 if (rcpt_in_progress)
2033 if (rcpt_smtp_response == NULL)
2034 rcpt_smtp_response = string_copy(msg);
2035 else if (rcpt_smtp_response_same &&
2036 Ustrcmp(rcpt_smtp_response, msg) != 0)
2037 rcpt_smtp_response_same = FALSE;
2038 rcpt_in_progress = FALSE;
2041 /* Not output the message, splitting it up into multiple lines if necessary. */
2045 uschar *nl = Ustrchr(msg, '\n');
2048 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2051 else if (nl[1] == 0 || no_multiline_responses)
2053 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2054 (int)(nl - msg), msg);
2059 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2061 while (isspace(*msg)) msg++;
2069 /*************************************************
2070 * Parse user SMTP message *
2071 *************************************************/
2073 /* This function allows for user messages overriding the response code details
2074 by providing a suitable response code string at the start of the message
2075 user_msg. Check the message for starting with a response code and optionally an
2076 extended status code. If found, check that the first digit is valid, and if so,
2077 change the code pointer and length to use the replacement. An invalid code
2078 causes a panic log; in this case, if the log messages is the same as the user
2079 message, we must also adjust the value of the log message to show the code that
2080 is actually going to be used (the original one).
2082 This function is global because it is called from receive.c as well as within
2085 Note that the code length returned includes the terminating whitespace
2086 character, which is always included in the regex match.
2089 code SMTP code, may involve extended status codes
2090 codelen length of smtp code; if > 4 there's an ESC
2092 log_msg optional log message, to be adjusted with the new SMTP code
2098 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2103 if (msg == NULL || *msg == NULL) return;
2105 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2106 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2109 if ((*msg)[0] != (*code)[0])
2111 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2112 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2113 if (log_msg != NULL && *log_msg == *msg)
2114 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2119 *codelen = ovector[1]; /* Includes final space */
2121 *msg += ovector[1]; /* Chop the code off the message */
2128 /*************************************************
2129 * Handle an ACL failure *
2130 *************************************************/
2132 /* This function is called when acl_check() fails. As well as calls from within
2133 this module, it is called from receive.c for an ACL after DATA. It sorts out
2134 logging the incident, and sets up the error response. A message containing
2135 newlines is turned into a multiline SMTP response, but for logging, only the
2138 There's a table of default permanent failure response codes to use in
2139 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2140 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2141 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2142 state, because there are broken clients that try VRFY before RCPT. A 5xx
2143 response should be given only when the address is positively known to be
2144 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2147 From Exim 4.63, it is possible to override the response code details by
2148 providing a suitable response code string at the start of the message provided
2149 in user_msg. The code's first digit is checked for validity.
2152 where where the ACL was called from
2154 user_msg a message that can be included in an SMTP response
2155 log_msg a message for logging
2157 Returns: 0 in most cases
2158 2 if the failure code was FAIL_DROP, in which case the
2159 SMTP connection should be dropped (this value fits with the
2160 "done" variable in smtp_setup_msg() below)
2164 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2166 BOOL drop = rc == FAIL_DROP;
2170 uschar *sender_info = US"";
2172 #ifdef WITH_CONTENT_SCAN
2173 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2175 (where == ACL_WHERE_PREDATA)? US"DATA" :
2176 (where == ACL_WHERE_DATA)? US"after DATA" :
2177 (smtp_cmd_data == NULL)?
2178 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2179 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2181 if (drop) rc = FAIL;
2183 /* Set the default SMTP code, and allow a user message to change it. */
2185 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2186 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2188 /* We used to have sender_address here; however, there was a bug that was not
2189 updating sender_address after a rewrite during a verify. When this bug was
2190 fixed, sender_address at this point became the rewritten address. I'm not sure
2191 this is what should be logged, so I've changed to logging the unrewritten
2192 address to retain backward compatibility. */
2194 #ifndef WITH_CONTENT_SCAN
2195 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2197 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2200 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
2201 sender_address_unrewritten : sender_address);
2204 /* If there's been a sender verification failure with a specific message, and
2205 we have not sent a response about it yet, do so now, as a preliminary line for
2206 failures, but not defers. However, always log it for defer, and log it for fail
2207 unless the sender_verify_fail log selector has been turned off. */
2209 if (sender_verified_failed != NULL &&
2210 !testflag(sender_verified_failed, af_sverify_told))
2212 BOOL save_rcpt_in_progress = rcpt_in_progress;
2213 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2215 setflag(sender_verified_failed, af_sverify_told);
2217 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2218 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2219 host_and_ident(TRUE),
2220 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2221 sender_verified_failed->address,
2222 (sender_verified_failed->message == NULL)? US"" :
2223 string_sprintf(": %s", sender_verified_failed->message));
2225 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2226 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2227 testflag(sender_verified_failed, af_verify_pmfail)?
2228 "Postmaster verification failed while checking <%s>\n%s\n"
2229 "Several RFCs state that you are required to have a postmaster\n"
2230 "mailbox for each mail domain. This host does not accept mail\n"
2231 "from domains whose servers reject the postmaster address."
2233 testflag(sender_verified_failed, af_verify_nsfail)?
2234 "Callback setup failed while verifying <%s>\n%s\n"
2235 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2236 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2237 "RFC requirements, and stops you from receiving standard bounce\n"
2238 "messages. This host does not accept mail from domains whose servers\n"
2241 "Verification failed for <%s>\n%s",
2242 sender_verified_failed->address,
2243 sender_verified_failed->user_message));
2245 rcpt_in_progress = save_rcpt_in_progress;
2248 /* Sort out text for logging */
2250 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2251 lognl = Ustrchr(log_msg, '\n');
2252 if (lognl != NULL) *lognl = 0;
2254 /* Send permanent failure response to the command, but the code used isn't
2255 always a 5xx one - see comments at the start of this function. If the original
2256 rc was FAIL_DROP we drop the connection and yield 2. */
2258 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2259 US"Administrative prohibition" : user_msg);
2261 /* Send temporary failure response to the command. Don't give any details,
2262 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2263 verb, and for a header verify when smtp_return_error_details is set.
2265 This conditional logic is all somewhat of a mess because of the odd
2266 interactions between temp_details and return_error_details. One day it should
2267 be re-implemented in a tidier fashion. */
2271 if (acl_temp_details && user_msg != NULL)
2273 if (smtp_return_error_details &&
2274 sender_verified_failed != NULL &&
2275 sender_verified_failed->message != NULL)
2277 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2279 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2282 smtp_respond(smtp_code, codelen, TRUE,
2283 US"Temporary local problem - please try later");
2286 /* Log the incident to the logs that are specified by log_reject_target
2287 (default main, reject). This can be empty to suppress logging of rejections. If
2288 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2289 is closing if required and return 2. */
2291 if (log_reject_target != 0)
2292 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2293 host_and_ident(TRUE),
2294 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2296 if (!drop) return 0;
2298 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2299 smtp_get_connection_info());
2301 /* Run the not-quit ACL, but without any custom messages. This should not be a
2302 problem, because we get here only if some other ACL has issued "drop", and
2303 in that case, *its* custom messages will have been used above. */
2305 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2312 /*************************************************
2313 * Handle SMTP exit when QUIT is not given *
2314 *************************************************/
2316 /* This function provides a logging/statistics hook for when an SMTP connection
2317 is dropped on the floor or the other end goes away. It's a global function
2318 because it's called from receive.c as well as this module. As well as running
2319 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2320 response, either with a custom message from the ACL, or using a default. There
2321 is one case, however, when no message is output - after "drop". In that case,
2322 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2323 passed to this function.
2325 In case things go wrong while processing this function, causing an error that
2326 may re-enter this funtion, there is a recursion check.
2329 reason What $smtp_notquit_reason will be set to in the ACL;
2330 if NULL, the ACL is not run
2331 code The error code to return as part of the response
2332 defaultrespond The default message if there's no user_msg
2338 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2341 uschar *user_msg = NULL;
2342 uschar *log_msg = NULL;
2344 /* Check for recursive acll */
2346 if (smtp_exit_function_called)
2348 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2352 smtp_exit_function_called = TRUE;
2354 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2356 if (acl_smtp_notquit != NULL && reason != NULL)
2358 smtp_notquit_reason = reason;
2359 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2362 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2366 /* Write an SMTP response if we are expected to give one. As the default
2367 responses are all internal, they should always fit in the buffer, but code a
2368 warning, just in case. Note that string_vformat() still leaves a complete
2369 string, even if it is incomplete. */
2371 if (code != NULL && defaultrespond != NULL)
2373 if (user_msg == NULL)
2377 va_start(ap, defaultrespond);
2378 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2379 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2380 smtp_printf("%s %s\r\n", code, buffer);
2384 smtp_respond(code, 3, TRUE, user_msg);
2392 /*************************************************
2393 * Verify HELO argument *
2394 *************************************************/
2396 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2397 matched. It is also called from ACL processing if verify = helo is used and
2398 verification was not previously tried (i.e. helo_try_verify_hosts was not
2399 matched). The result of its processing is to set helo_verified and
2400 helo_verify_failed. These variables should both be FALSE for this function to
2403 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2404 for IPv6 ::ffff: literals.
2407 Returns: TRUE if testing was completed;
2408 FALSE on a temporary failure
2412 smtp_verify_helo(void)
2416 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2419 if (sender_helo_name == NULL)
2421 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2424 /* Deal with the case of -bs without an IP address */
2426 else if (sender_host_address == NULL)
2428 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2429 helo_verified = TRUE;
2432 /* Deal with the more common case when there is a sending IP address */
2434 else if (sender_helo_name[0] == '[')
2436 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2437 Ustrlen(sender_host_address)) == 0;
2442 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2443 helo_verified = Ustrncmp(sender_helo_name + 1,
2444 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2449 { if (helo_verified) debug_printf("matched host address\n"); }
2452 /* Do a reverse lookup if one hasn't already given a positive or negative
2453 response. If that fails, or the name doesn't match, try checking with a forward
2458 if (sender_host_name == NULL && !host_lookup_failed)
2459 yield = host_name_lookup() != DEFER;
2461 /* If a host name is known, check it and all its aliases. */
2463 if (sender_host_name != NULL)
2465 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2469 HDEBUG(D_receive) debug_printf("matched host name\n");
2473 uschar **aliases = sender_host_aliases;
2474 while (*aliases != NULL)
2476 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2477 if (helo_verified) break;
2482 debug_printf("matched alias %s\n", *(--aliases));
2487 /* Final attempt: try a forward lookup of the helo name */
2493 h.name = sender_helo_name;
2497 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2499 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2500 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2505 if (Ustrcmp(hh->address, sender_host_address) == 0)
2507 helo_verified = TRUE;
2509 debug_printf("IP address for %s matches calling address\n",
2519 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2526 /*************************************************
2527 * Send user response message *
2528 *************************************************/
2530 /* This function is passed a default response code and a user message. It calls
2531 smtp_message_code() to check and possibly modify the response code, and then
2532 calls smtp_respond() to transmit the response. I put this into a function
2533 just to avoid a lot of repetition.
2536 code the response code
2537 user_msg the user message
2543 smtp_user_msg(uschar *code, uschar *user_msg)
2546 smtp_message_code(&code, &len, &user_msg, NULL);
2547 smtp_respond(code, len, TRUE, user_msg);
2553 /*************************************************
2554 * Initialize for SMTP incoming message *
2555 *************************************************/
2557 /* This function conducts the initial dialogue at the start of an incoming SMTP
2558 message, and builds a list of recipients. However, if the incoming message
2559 is part of a batch (-bS option) a separate function is called since it would
2560 be messy having tests splattered about all over this function. This function
2561 therefore handles the case where interaction is occurring. The input and output
2562 files are set up in smtp_in and smtp_out.
2564 The global recipients_list is set to point to a vector of recipient_item
2565 blocks, whose number is given by recipients_count. This is extended by the
2566 receive_add_recipient() function. The global variable sender_address is set to
2567 the sender's address. The yield is +1 if a message has been successfully
2568 started, 0 if a QUIT command was encountered or the connection was refused from
2569 the particular host, or -1 if the connection was lost.
2573 Returns: > 0 message successfully started (reached DATA)
2574 = 0 QUIT read or end of file reached or call refused
2579 smtp_setup_msg(void)
2582 BOOL toomany = FALSE;
2583 BOOL discarded = FALSE;
2584 BOOL last_was_rej_mail = FALSE;
2585 BOOL last_was_rcpt = FALSE;
2586 void *reset_point = store_get(0);
2588 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2590 /* Reset for start of new message. We allow one RSET not to be counted as a
2591 nonmail command, for those MTAs that insist on sending it between every
2592 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2593 TLS between messages (an Exim client may do this if it has messages queued up
2594 for the host). Note: we do NOT reset AUTH at this point. */
2596 smtp_reset(reset_point);
2597 message_ended = END_NOTSTARTED;
2599 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2600 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2601 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2603 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2606 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2608 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2610 /* Batched SMTP is handled in a different function. */
2612 if (smtp_batched_input) return smtp_setup_batch_msg();
2614 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2615 value. The values are 2 larger than the required yield of the function. */
2620 uschar *etrn_command;
2621 uschar *etrn_serialize_key;
2623 uschar *log_msg, *smtp_code;
2624 uschar *user_msg = NULL;
2625 uschar *recipient = NULL;
2626 uschar *hello = NULL;
2627 uschar *set_id = NULL;
2629 BOOL was_rej_mail = FALSE;
2630 BOOL was_rcpt = FALSE;
2631 void (*oldsignal)(int);
2633 int start, end, sender_domain, recipient_domain;
2638 switch(smtp_read_command(TRUE))
2640 /* The AUTH command is not permitted to occur inside a transaction, and may
2641 occur successfully only once per connection. Actually, that isn't quite
2642 true. When TLS is started, all previous information about a connection must
2643 be discarded, so a new AUTH is permitted at that time.
2645 AUTH may only be used when it has been advertised. However, it seems that
2646 there are clients that send AUTH when it hasn't been advertised, some of
2647 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2648 So there's a get-out that allows this to happen.
2650 AUTH is initially labelled as a "nonmail command" so that one occurrence
2651 doesn't get counted. We change the label here so that multiple failing
2652 AUTHS will eventually hit the nonmail threshold. */
2656 authentication_failed = TRUE;
2657 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2659 if (!auth_advertised && !allow_auth_unadvertised)
2661 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2662 US"AUTH command used when not advertised");
2665 if (sender_host_authenticated != NULL)
2667 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2668 US"already authenticated");
2671 if (sender_address != NULL)
2673 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2674 US"not permitted in mail transaction");
2680 if (acl_smtp_auth != NULL)
2682 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2685 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2690 /* Find the name of the requested authentication mechanism. */
2693 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
2695 if (!isalnum(c) && c != '-' && c != '_')
2697 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2698 US"invalid character in authentication mechanism name");
2704 /* If not at the end of the line, we must be at white space. Terminate the
2705 name and move the pointer on to any data that may be present. */
2707 if (*smtp_cmd_data != 0)
2709 *smtp_cmd_data++ = 0;
2710 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
2713 /* Search for an authentication mechanism which is configured for use
2714 as a server and which has been advertised (unless, sigh, allow_auth_
2715 unadvertised is set). */
2717 for (au = auths; au != NULL; au = au->next)
2719 if (strcmpic(s, au->public_name) == 0 && au->server &&
2720 (au->advertised || allow_auth_unadvertised)) break;
2725 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2726 string_sprintf("%s authentication mechanism not supported", s));
2730 /* Run the checking code, passing the remainder of the command line as
2731 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2732 it as the only set numerical variable. The authenticator may set $auth<n>
2733 and also set other numeric variables. The $auth<n> variables are preferred
2734 nowadays; the numerical variables remain for backwards compatibility.
2736 Afterwards, have a go at expanding the set_id string, even if
2737 authentication failed - for bad passwords it can be useful to log the
2738 userid. On success, require set_id to expand and exist, and put it in
2739 authenticated_id. Save this in permanent store, as the working store gets
2740 reset at HELO, RSET, etc. */
2742 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2744 expand_nlength[0] = 0; /* $0 contains nothing */
2746 c = (au->info->servercode)(au, smtp_cmd_data);
2747 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2748 expand_nmax = -1; /* Reset numeric variables */
2749 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2751 /* The value of authenticated_id is stored in the spool file and printed in
2752 log lines. It must not contain binary zeros or newline characters. In
2753 normal use, it never will, but when playing around or testing, this error
2754 can (did) happen. To guard against this, ensure that the id contains only
2755 printing characters. */
2757 if (set_id != NULL) set_id = string_printing(set_id);
2759 /* For the non-OK cases, set up additional logging data if set_id
2764 if (set_id != NULL && *set_id != 0)
2765 set_id = string_sprintf(" (set_id=%s)", set_id);
2769 /* Switch on the result */
2774 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2776 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2777 sender_host_authenticated = au->name;
2778 authentication_failed = FALSE;
2780 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2781 ((sender_host_address != NULL)? pnlocal : 0);
2782 s = ss = US"235 Authentication succeeded";
2783 authenticated_by = au;
2787 /* Authentication succeeded, but we failed to expand the set_id string.
2788 Treat this as a temporary error. */
2790 auth_defer_msg = expand_string_message;
2794 s = string_sprintf("435 Unable to authenticate at present%s",
2795 auth_defer_user_msg);
2796 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2797 set_id, auth_defer_msg);
2801 s = ss = US"501 Invalid base64 data";
2805 s = ss = US"501 Authentication cancelled";
2809 s = ss = US"553 Initial data not expected";
2813 s = US"535 Incorrect authentication data";
2814 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2818 s = US"435 Internal error";
2819 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2820 "check", set_id, c);
2824 smtp_printf("%s\r\n", s);
2826 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2827 au->name, host_and_ident(FALSE), ss);
2829 break; /* AUTH_CMD */
2831 /* The HELO/EHLO commands are permitted to appear in the middle of a
2832 session as well as at the beginning. They have the effect of a reset in
2833 addition to their other functions. Their absence at the start cannot be
2834 taken to be an error.
2838 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2839 or 502 failure replies MUST be returned as appropriate. The SMTP
2840 server MUST stay in the same state after transmitting these replies
2841 that it was in before the EHLO was received.
2843 Therefore, we do not do the reset until after checking the command for
2844 acceptability. This change was made for Exim release 4.11. Previously
2845 it did the reset first. */
2858 HELO_EHLO: /* Common code for HELO and EHLO */
2859 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2860 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2862 /* Reject the HELO if its argument was invalid or non-existent. A
2863 successful check causes the argument to be saved in malloc store. */
2865 if (!check_helo(smtp_cmd_data))
2867 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2869 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2870 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2871 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2872 string_printing(smtp_cmd_argument));
2874 if (++synprot_error_count > smtp_max_synprot_errors)
2876 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2877 "syntax or protocol errors (last command was \"%s\")",
2878 host_and_ident(FALSE), smtp_cmd_buffer);
2885 /* If sender_host_unknown is true, we have got here via the -bs interface,
2886 not called from inetd. Otherwise, we are running an IP connection and the
2887 host address will be set. If the helo name is the primary name of this
2888 host and we haven't done a reverse lookup, force one now. If helo_required
2889 is set, ensure that the HELO name matches the actual host. If helo_verify
2890 is set, do the same check, but softly. */
2892 if (!sender_host_unknown)
2894 BOOL old_helo_verified = helo_verified;
2895 uschar *p = smtp_cmd_data;
2897 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2900 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2901 because otherwise the log can be confusing. */
2903 if (sender_host_name == NULL &&
2904 (deliver_domain = sender_helo_name, /* set $domain */
2905 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2906 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2907 (void)host_name_lookup();
2909 /* Rebuild the fullhost info to include the HELO name (and the real name
2910 if it was looked up.) */
2912 host_build_sender_fullhost(); /* Rebuild */
2913 set_process_info("handling%s incoming connection from %s",
2914 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2916 /* Verify if configured. This doesn't give much security, but it does
2917 make some people happy to be able to do it. If helo_required is set,
2918 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2919 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2920 now obsolescent, since the verification can now be requested selectively
2923 helo_verified = helo_verify_failed = FALSE;
2924 if (helo_required || helo_verify)
2926 BOOL tempfail = !smtp_verify_helo();
2931 smtp_printf("%d %s argument does not match calling host\r\n",
2932 tempfail? 451 : 550, hello);
2933 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2934 tempfail? "temporarily " : "",
2935 hello, sender_helo_name, host_and_ident(FALSE));
2936 helo_verified = old_helo_verified;
2937 break; /* End of HELO/EHLO processing */
2939 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2940 "helo_try_verify_hosts\n", hello);
2945 #ifdef EXPERIMENTAL_SPF
2946 /* set up SPF context */
2947 spf_init(sender_helo_name, sender_host_address);
2950 /* Apply an ACL check if one is defined; afterwards, recheck
2951 synchronization in case the client started sending in a delay. */
2953 if (acl_smtp_helo != NULL)
2955 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2958 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2959 sender_helo_name = NULL;
2960 host_build_sender_fullhost(); /* Rebuild */
2963 else if (!check_sync()) goto SYNC_FAILURE;
2966 /* Generate an OK reply. The default string includes the ident if present,
2967 and also the IP address if present. Reflecting back the ident is intended
2968 as a deterrent to mail forgers. For maximum efficiency, and also because
2969 some broken systems expect each response to be in a single packet, arrange
2970 that the entire reply is sent in one write(). */
2972 auth_advertised = FALSE;
2973 pipelining_advertised = FALSE;
2975 tls_advertised = FALSE;
2978 smtp_code = US"250 "; /* Default response code plus space*/
2979 if (user_msg == NULL)
2981 s = string_sprintf("%.3s %s Hello %s%s%s",
2983 smtp_active_hostname,
2984 (sender_ident == NULL)? US"" : sender_ident,
2985 (sender_ident == NULL)? US"" : US" at ",
2986 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2991 if (sender_host_address != NULL)
2993 s = string_cat(s, &size, &ptr, US" [", 2);
2994 s = string_cat(s, &size, &ptr, sender_host_address,
2995 Ustrlen(sender_host_address));
2996 s = string_cat(s, &size, &ptr, US"]", 1);
3000 /* A user-supplied EHLO greeting may not contain more than one line. Note
3001 that the code returned by smtp_message_code() includes the terminating
3002 whitespace character. */
3008 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3009 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3010 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3012 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3013 "newlines: message truncated: %s", string_printing(s));
3020 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3022 /* If we received EHLO, we must create a multiline response which includes
3023 the functions supported. */
3029 /* I'm not entirely happy with this, as an MTA is supposed to check
3030 that it has enough room to accept a message of maximum size before
3031 it sends this. However, there seems little point in not sending it.
3032 The actual size check happens later at MAIL FROM time. By postponing it
3033 till then, VRFY and EXPN can be used after EHLO when space is short. */
3035 if (thismessage_size_limit > 0)
3037 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3038 thismessage_size_limit);
3039 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3043 s = string_cat(s, &size, &ptr, smtp_code, 3);
3044 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3047 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3048 clean; if it has an 8-bit character in its hand, it just sends it. It
3049 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3050 However, some users want this option simply in order to stop MUAs
3051 mangling messages that contain top-bit-set characters. It is therefore
3052 provided as an option. */
3054 if (accept_8bitmime)
3056 s = string_cat(s, &size, &ptr, smtp_code, 3);
3057 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3060 /* Advertise ETRN if there's an ACL checking whether a host is
3061 permitted to issue it; a check is made when any host actually tries. */
3063 if (acl_smtp_etrn != NULL)
3065 s = string_cat(s, &size, &ptr, smtp_code, 3);
3066 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3069 /* Advertise EXPN if there's an ACL checking whether a host is
3070 permitted to issue it; a check is made when any host actually tries. */
3072 if (acl_smtp_expn != NULL)
3074 s = string_cat(s, &size, &ptr, smtp_code, 3);
3075 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3078 /* Exim is quite happy with pipelining, so let the other end know that
3079 it is safe to use it, unless advertising is disabled. */
3081 if (pipelining_enable &&
3082 verify_check_host(&pipelining_advertise_hosts) == OK)
3084 s = string_cat(s, &size, &ptr, smtp_code, 3);
3085 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3086 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3087 pipelining_advertised = TRUE;
3090 /* If any server authentication mechanisms are configured, advertise
3091 them if the current host is in auth_advertise_hosts. The problem with
3092 advertising always is that some clients then require users to
3093 authenticate (and aren't configurable otherwise) even though it may not
3094 be necessary (e.g. if the host is in host_accept_relay).
3096 RFC 2222 states that SASL mechanism names contain only upper case
3097 letters, so output the names in upper case, though we actually recognize
3098 them in either case in the AUTH command. */
3102 if (verify_check_host(&auth_advertise_hosts) == OK)
3106 for (au = auths; au != NULL; au = au->next)
3108 if (au->server && (au->advertise_condition == NULL ||
3109 expand_check_condition(au->advertise_condition, au->name,
3110 US"authenticator")))
3115 s = string_cat(s, &size, &ptr, smtp_code, 3);
3116 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3118 auth_advertised = TRUE;
3121 s = string_cat(s, &size, &ptr, US" ", 1);
3122 s = string_cat(s, &size, &ptr, au->public_name,
3123 Ustrlen(au->public_name));
3124 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3125 au->advertised = TRUE;
3127 else au->advertised = FALSE;
3129 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3133 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3134 if it has been included in the binary, and the host matches
3135 tls_advertise_hosts. We must *not* advertise if we are already in a
3136 secure connection. */
3139 if (tls_active < 0 &&
3140 verify_check_host(&tls_advertise_hosts) != FAIL)
3142 s = string_cat(s, &size, &ptr, smtp_code, 3);
3143 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3144 tls_advertised = TRUE;
3148 /* Finish off the multiline reply with one that is always available. */
3150 s = string_cat(s, &size, &ptr, smtp_code, 3);
3151 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3154 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3160 if (tls_active >= 0) (void)tls_write(s, ptr); else
3163 (void)fwrite(s, 1, ptr, smtp_out);
3167 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3168 memmove(cr, cr + 1, (ptr--) - (cr - s));
3169 debug_printf("SMTP>> %s", s);
3173 /* Reset the protocol and the state, abandoning any previous message. */
3175 received_protocol = (esmtp?
3177 ((sender_host_authenticated != NULL)? pauthed : 0) +
3178 ((tls_active >= 0)? pcrpted : 0)]
3180 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
3182 ((sender_host_address != NULL)? pnlocal : 0);
3184 smtp_reset(reset_point);
3186 break; /* HELO/EHLO */
3189 /* The MAIL command requires an address as an operand. All we do
3190 here is to parse it for syntactic correctness. The form "<>" is
3191 a special case which converts into an empty string. The start/end
3192 pointers in the original are not used further for this address, as
3193 it is the canonical extracted address which is all that is kept. */
3197 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3198 was_rej_mail = TRUE; /* Reset if accepted */
3200 if (helo_required && !helo_seen)
3202 smtp_printf("503 HELO or EHLO required\r\n");
3203 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3204 "HELO/EHLO given", host_and_ident(FALSE));
3208 if (sender_address != NULL)
3210 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3211 US"sender already given");
3215 if (smtp_cmd_data[0] == 0)
3217 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3218 US"MAIL must have an address operand");
3222 /* Check to see if the limit for messages per connection would be
3223 exceeded by accepting further messages. */
3225 if (smtp_accept_max_per_connection > 0 &&
3226 smtp_mailcmd_count > smtp_accept_max_per_connection)
3228 smtp_printf("421 too many messages in this connection\r\n");
3229 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3230 "messages in one connection", host_and_ident(TRUE));
3234 /* Reset for start of message - even if this is going to fail, we
3235 obviously need to throw away any previous data. */
3237 smtp_reset(reset_point);
3239 sender_data = recipient_data = NULL;
3241 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3245 uschar *name, *value, *end;
3246 unsigned long int size;
3248 if (!extract_option(&name, &value)) break;
3250 /* Handle SIZE= by reading the value. We don't do the check till later,
3251 in order to be able to log the sender address on failure. */
3253 if (strcmpic(name, US"SIZE") == 0 &&
3254 ((size = Ustrtoul(value, &end, 10)), *end == 0))
3256 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3258 message_size = (int)size;
3261 /* If this session was initiated with EHLO and accept_8bitmime is set,
3262 Exim will have indicated that it supports the BODY=8BITMIME option. In
3263 fact, it does not support this according to the RFCs, in that it does not
3264 take any special action for forwarding messages containing 8-bit
3265 characters. That is why accept_8bitmime is not the default setting, but
3266 some sites want the action that is provided. We recognize both "8BITMIME"
3267 and "7BIT" as body types, but take no action. */
3269 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
3270 (strcmpic(value, US"8BITMIME") == 0 ||
3271 strcmpic(value, US"7BIT") == 0)) {}
3273 /* Handle the AUTH extension. If the value given is not "<>" and either
3274 the ACL says "yes" or there is no ACL but the sending host is
3275 authenticated, we set it up as the authenticated sender. However, if the
3276 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3277 the condition is met. The value of AUTH is an xtext, which means that +,
3278 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3281 else if (strcmpic(name, US"AUTH") == 0)
3283 if (Ustrcmp(value, "<>") != 0)
3288 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3290 /* Put back terminator overrides for error message */
3293 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3294 US"invalid data for AUTH");
3298 if (acl_smtp_mailauth == NULL)
3300 ignore_msg = US"client not authenticated";
3301 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3305 ignore_msg = US"rejected by ACL";
3306 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3307 &user_msg, &log_msg);
3313 if (authenticated_by == NULL ||
3314 authenticated_by->mail_auth_condition == NULL ||
3315 expand_check_condition(authenticated_by->mail_auth_condition,
3316 authenticated_by->name, US"authenticator"))
3317 break; /* Accept the AUTH */
3319 ignore_msg = US"server_mail_auth_condition failed";
3320 if (authenticated_id != NULL)
3321 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3322 ignore_msg, authenticated_id);
3327 authenticated_sender = NULL;
3328 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3329 value, host_and_ident(TRUE), ignore_msg);
3332 /* Should only get DEFER or ERROR here. Put back terminator
3333 overrides for error message */
3338 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3345 /* Unknown option. Stick back the terminator characters and break
3346 the loop. An error for a malformed address will occur. */
3356 /* If we have passed the threshold for rate limiting, apply the current
3357 delay, and update it for next time, provided this is a limited host. */
3359 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3360 verify_check_host(&smtp_ratelimit_hosts) == OK)
3362 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3363 smtp_delay_mail/1000.0);
3364 millisleep((int)smtp_delay_mail);
3365 smtp_delay_mail *= smtp_rlm_factor;
3366 if (smtp_delay_mail > (double)smtp_rlm_limit)
3367 smtp_delay_mail = (double)smtp_rlm_limit;
3370 /* Now extract the address, first applying any SMTP-time rewriting. The
3371 TRUE flag allows "<>" as a sender address. */
3373 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3374 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3375 global_rewrite_rules) : smtp_cmd_data;
3377 /* rfc821_domains = TRUE; << no longer needed */
3379 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3381 /* rfc821_domains = FALSE; << no longer needed */
3383 if (raw_sender == NULL)
3385 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3389 sender_address = raw_sender;
3391 /* If there is a configured size limit for mail, check that this message
3392 doesn't exceed it. The check is postponed to this point so that the sender
3395 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3397 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3398 log_write(L_size_reject,
3399 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3400 "message too big: size%s=%d max=%d",
3402 host_and_ident(TRUE),
3403 (message_size == INT_MAX)? ">" : "",
3405 thismessage_size_limit);
3406 sender_address = NULL;
3410 /* Check there is enough space on the disk unless configured not to.
3411 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3412 plus the current message - i.e. we accept the message only if it won't
3413 reduce the space below the threshold. Add 5000 to the size to allow for
3414 overheads such as the Received: line and storing of recipients, etc.
3415 By putting the check here, even when SIZE is not given, it allow VRFY
3416 and EXPN etc. to be used when space is short. */
3418 if (!receive_check_fs(
3419 (smtp_check_spool_space && message_size >= 0)?
3420 message_size + 5000 : 0))
3422 smtp_printf("452 Space shortage, please try later\r\n");
3423 sender_address = NULL;
3427 /* If sender_address is unqualified, reject it, unless this is a locally
3428 generated message, or the sending host or net is permitted to send
3429 unqualified addresses - typically local machines behaving as MUAs -
3430 in which case just qualify the address. The flag is set above at the start
3431 of the SMTP connection. */
3433 if (sender_domain == 0 && sender_address[0] != 0)
3435 if (allow_unqualified_sender)
3437 sender_domain = Ustrlen(sender_address) + 1;
3438 sender_address = rewrite_address_qualify(sender_address, FALSE);
3439 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3444 smtp_printf("501 %s: sender address must contain a domain\r\n",
3446 log_write(L_smtp_syntax_error,
3447 LOG_MAIN|LOG_REJECT,
3448 "unqualified sender rejected: <%s> %s%s",
3450 host_and_ident(TRUE),
3452 sender_address = NULL;
3457 /* Apply an ACL check if one is defined, before responding. Afterwards,
3458 when pipelining is not advertised, do another sync check in case the ACL
3459 delayed and the client started sending in the meantime. */
3461 if (acl_smtp_mail == NULL) rc = OK; else
3463 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3464 if (rc == OK && !pipelining_advertised && !check_sync())
3468 if (rc == OK || rc == DISCARD)
3470 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3471 else smtp_user_msg(US"250", user_msg);
3472 smtp_delay_rcpt = smtp_rlr_base;
3473 recipients_discarded = (rc == DISCARD);
3474 was_rej_mail = FALSE;
3478 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3479 sender_address = NULL;
3484 /* The RCPT command requires an address as an operand. There may be any
3485 number of RCPT commands, specifying multiple recipients. We build them all
3486 into a data structure. The start/end values given by parse_extract_address
3487 are not used, as we keep only the extracted address. */
3492 was_rcpt = rcpt_in_progress = TRUE;
3494 /* There must be a sender address; if the sender was rejected and
3495 pipelining was advertised, we assume the client was pipelining, and do not
3496 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3497 get the same treatment. */
3499 if (sender_address == NULL)
3501 if (pipelining_advertised && last_was_rej_mail)
3503 smtp_printf("503 sender not yet given\r\n");
3504 was_rej_mail = TRUE;
3508 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3509 US"sender not yet given");
3510 was_rcpt = FALSE; /* Not a valid RCPT */
3516 /* Check for an operand */
3518 if (smtp_cmd_data[0] == 0)
3520 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3521 US"RCPT must have an address operand");
3526 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3527 as a recipient address */
3529 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3530 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3531 global_rewrite_rules) : smtp_cmd_data;
3533 /* rfc821_domains = TRUE; << no longer needed */
3534 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3535 &recipient_domain, FALSE);
3536 /* rfc821_domains = FALSE; << no longer needed */
3538 if (recipient == NULL)
3540 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3545 /* If the recipient address is unqualified, reject it, unless this is a
3546 locally generated message. However, unqualified addresses are permitted
3547 from a configured list of hosts and nets - typically when behaving as
3548 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3549 really. The flag is set at the start of the SMTP connection.
3551 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3552 assumed this meant "reserved local part", but the revision of RFC 821 and
3553 friends now makes it absolutely clear that it means *mailbox*. Consequently
3554 we must always qualify this address, regardless. */
3556 if (recipient_domain == 0)
3558 if (allow_unqualified_recipient ||
3559 strcmpic(recipient, US"postmaster") == 0)
3561 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3563 recipient_domain = Ustrlen(recipient) + 1;
3564 recipient = rewrite_address_qualify(recipient, TRUE);
3569 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3571 log_write(L_smtp_syntax_error,
3572 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3573 "<%s> %s%s", recipient, host_and_ident(TRUE),
3579 /* Check maximum allowed */
3581 if (rcpt_count > recipients_max && recipients_max > 0)
3583 if (recipients_max_reject)
3586 smtp_printf("552 too many recipients\r\n");
3588 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3589 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3594 smtp_printf("452 too many recipients\r\n");
3596 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3597 "temporarily rejected: sender=<%s> %s", sender_address,
3598 host_and_ident(TRUE));
3605 /* If we have passed the threshold for rate limiting, apply the current
3606 delay, and update it for next time, provided this is a limited host. */
3608 if (rcpt_count > smtp_rlr_threshold &&
3609 verify_check_host(&smtp_ratelimit_hosts) == OK)
3611 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3612 smtp_delay_rcpt/1000.0);
3613 millisleep((int)smtp_delay_rcpt);
3614 smtp_delay_rcpt *= smtp_rlr_factor;
3615 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3616 smtp_delay_rcpt = (double)smtp_rlr_limit;
3619 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3620 for them. Otherwise, check the access control list for this recipient. As
3621 there may be a delay in this, re-check for a synchronization error
3622 afterwards, unless pipelining was advertised. */
3624 if (recipients_discarded) rc = DISCARD; else
3626 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
3628 if (rc == OK && !pipelining_advertised && !check_sync())
3632 /* The ACL was happy */
3636 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3637 else smtp_user_msg(US"250", user_msg);
3638 receive_add_recipient(recipient, -1);
3641 /* The recipient was discarded */
3643 else if (rc == DISCARD)
3645 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3646 else smtp_user_msg(US"250", user_msg);
3649 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3650 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3651 (sender_address_unrewritten != NULL)?
3652 sender_address_unrewritten : sender_address,
3653 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3654 (log_msg == NULL)? US"" : US": ",
3655 (log_msg == NULL)? US"" : log_msg);
3658 /* Either the ACL failed the address, or it was deferred. */
3662 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3663 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3668 /* The DATA command is legal only if it follows successful MAIL FROM
3669 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3670 not counted as a protocol error if it follows RCPT (which must have been
3671 rejected if there are no recipients.) This function is complete when a
3672 valid DATA command is encountered.
3674 Note concerning the code used: RFC 2821 says this:
3676 - If there was no MAIL, or no RCPT, command, or all such commands
3677 were rejected, the server MAY return a "command out of sequence"
3678 (503) or "no valid recipients" (554) reply in response to the
3681 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3682 because it is the same whether pipelining is in use or not.
3684 If all the RCPT commands that precede DATA provoked the same error message
3685 (often indicating some kind of system error), it is helpful to include it
3686 with the DATA rejection (an idea suggested by Tony Finch). */
3690 if (!discarded && recipients_count <= 0)
3692 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
3694 uschar *code = US"503";
3695 int len = Ustrlen(rcpt_smtp_response);
3696 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
3698 /* Responses from smtp_printf() will have \r\n on the end */
3699 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
3700 rcpt_smtp_response[len-2] = 0;
3701 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
3703 if (pipelining_advertised && last_was_rcpt)
3704 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
3706 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3707 US"valid RCPT command must precede DATA");
3711 if (toomany && recipients_max_reject)
3713 sender_address = NULL; /* This will allow a new MAIL without RSET */
3714 sender_address_unrewritten = NULL;
3715 smtp_printf("554 Too many recipients\r\n");
3719 /* If there is an ACL, re-check the synchronization afterwards, since the
3720 ACL may have delayed. */
3722 if (acl_smtp_predata == NULL) rc = OK; else
3724 enable_dollar_recipients = TRUE;
3725 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3727 enable_dollar_recipients = FALSE;
3728 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
3733 if (user_msg == NULL)
3734 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3735 else smtp_user_msg(US"354", user_msg);
3737 message_ended = END_NOTENDED; /* Indicate in middle of data */
3740 /* Either the ACL failed the address, or it was deferred. */
3743 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3749 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3751 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3757 /* rfc821_domains = TRUE; << no longer needed */
3758 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
3759 &recipient_domain, FALSE);
3760 /* rfc821_domains = FALSE; << no longer needed */
3762 if (address == NULL)
3763 s = string_sprintf("501 %s", errmess);
3766 address_item *addr = deliver_make_addr(address, FALSE);
3767 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3768 -1, -1, NULL, NULL, NULL))
3771 s = string_sprintf("250 <%s> is deliverable", address);
3775 s = (addr->user_message != NULL)?
3776 string_sprintf("451 <%s> %s", address, addr->user_message) :
3777 string_sprintf("451 Cannot resolve <%s> at this time", address);
3781 s = (addr->user_message != NULL)?
3782 string_sprintf("550 <%s> %s", address, addr->user_message) :
3783 string_sprintf("550 <%s> is not deliverable", address);
3784 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3785 smtp_cmd_argument, host_and_ident(TRUE));
3790 smtp_printf("%s\r\n", s);
3797 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3799 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3802 BOOL save_log_testing_mode = log_testing_mode;
3803 address_test_mode = log_testing_mode = TRUE;
3804 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
3805 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3807 address_test_mode = FALSE;
3808 log_testing_mode = save_log_testing_mode; /* true for -bh */
3817 if (!tls_advertised)
3819 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3820 US"STARTTLS command used when not advertised");
3824 /* Apply an ACL check if one is defined */
3826 if (acl_smtp_starttls != NULL)
3828 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3832 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3837 /* RFC 2487 is not clear on when this command may be sent, though it
3838 does state that all information previously obtained from the client
3839 must be discarded if a TLS session is started. It seems reasonble to
3840 do an implied RSET when STARTTLS is received. */
3842 incomplete_transaction_log(US"STARTTLS");
3843 smtp_reset(reset_point);
3845 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3847 /* There's an attack where more data is read in past the STARTTLS command
3848 before TLS is negotiated, then assumed to be part of the secure session
3849 when used afterwards; we use segregated input buffers, so are not
3850 vulnerable, but we want to note when it happens and, for sheer paranoia,
3851 ensure that the buffer is "wiped".
3852 Pipelining sync checks will normally have protected us too, unless disabled
3853 by configuration. */
3855 if (receive_smtp_buffered())
3858 debug_printf("Non-empty input buffer after STARTTLS; naive attack?");
3860 smtp_inend = smtp_inptr = smtp_inbuffer;
3861 /* and if TLS is already active, tls_server_start() should fail */
3864 /* There is nothing we value in the input buffer and if TLS is succesfully
3865 negotiated, we won't use this buffer again; if TLS fails, we'll just read
3866 fresh content into it. The buffer contains arbitrary content from an
3867 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
3868 It seems safest to just wipe away the content rather than leave it as a
3869 target to jump to. */
3871 memset(smtp_inbuffer, 0, in_buffer_size);
3873 /* Attempt to start up a TLS session, and if successful, discard all
3874 knowledge that was obtained previously. At least, that's what the RFC says,
3875 and that's what happens by default. However, in order to work round YAEB,
3876 there is an option to remember the esmtp state. Sigh.
3878 We must allow for an extra EHLO command and an extra AUTH command after
3879 STARTTLS that don't add to the nonmail command count. */
3881 if ((rc = tls_server_start(tls_require_ciphers, gnutls_require_mac,
3882 gnutls_require_kx, gnutls_require_proto)) == OK)
3884 if (!tls_remember_esmtp)
3885 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3886 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3887 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3888 if (sender_helo_name != NULL)
3890 store_free(sender_helo_name);
3891 sender_helo_name = NULL;
3892 host_build_sender_fullhost(); /* Rebuild */
3893 set_process_info("handling incoming TLS connection from %s",
3894 host_and_ident(FALSE));
3896 received_protocol = (esmtp?
3897 protocols[pextend + pcrpted +
3898 ((sender_host_authenticated != NULL)? pauthed : 0)]
3900 protocols[pnormal + pcrpted])
3902 ((sender_host_address != NULL)? pnlocal : 0);
3904 sender_host_authenticated = NULL;
3905 authenticated_id = NULL;
3906 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3907 DEBUG(D_tls) debug_printf("TLS active\n");
3908 break; /* Successful STARTTLS */
3911 /* Some local configuration problem was discovered before actually trying
3912 to do a TLS handshake; give a temporary error. */
3914 else if (rc == DEFER)
3916 smtp_printf("454 TLS currently unavailable\r\n");
3920 /* Hard failure. Reject everything except QUIT or closed connection. One
3921 cause for failure is a nested STARTTLS, in which case tls_active remains
3922 set, but we must still reject all incoming commands. */
3924 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3927 switch(smtp_read_command(FALSE))
3930 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3931 smtp_get_connection_info());
3932 smtp_notquit_exit(US"tls-failed", NULL, NULL);
3936 /* It is perhaps arguable as to which exit ACL should be called here,
3937 but as it is probably a situtation that almost never arises, it
3938 probably doesn't matter. We choose to call the real QUIT ACL, which in
3939 some sense is perhaps "right". */
3943 if (acl_smtp_quit != NULL)
3945 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_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);
3955 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3956 smtp_get_connection_info());
3961 smtp_printf("554 Security failure\r\n");
3970 /* The ACL for QUIT is provided for gathering statistical information or
3971 similar; it does not affect the response code, but it can supply a custom
3976 incomplete_transaction_log(US"QUIT");
3977 if (acl_smtp_quit != NULL)
3979 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
3981 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3984 if (user_msg == NULL)
3985 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3987 smtp_respond(US"221", 3, TRUE, user_msg);
3994 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3995 smtp_get_connection_info());
4001 incomplete_transaction_log(US"RSET");
4002 smtp_reset(reset_point);
4004 smtp_printf("250 Reset OK\r\n");
4005 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
4011 smtp_printf("250 OK\r\n");
4015 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
4016 used, a check will be done for permitted hosts. Show STARTTLS only if not
4017 already in a TLS session and if it would be advertised in the EHLO
4022 smtp_printf("214-Commands supported:\r\n");
4026 Ustrcat(buffer, " AUTH");
4028 if (tls_active < 0 &&
4029 verify_check_host(&tls_advertise_hosts) != FAIL)
4030 Ustrcat(buffer, " STARTTLS");
4032 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
4033 Ustrcat(buffer, " NOOP QUIT RSET HELP");
4034 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4035 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4036 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4037 smtp_printf("214%s\r\n", buffer);
4043 incomplete_transaction_log(US"connection lost");
4044 smtp_notquit_exit(US"connection-lost", US"421",
4045 US"%s lost input connection", smtp_active_hostname);
4047 /* Don't log by default unless in the middle of a message, as some mailers
4048 just drop the call rather than sending QUIT, and it clutters up the logs.
4051 if (sender_address != NULL || recipients_count > 0)
4052 log_write(L_lost_incoming_connection,
4054 "unexpected %s while reading SMTP command from %s%s",
4055 sender_host_unknown? "EOF" : "disconnection",
4056 host_and_ident(FALSE), smtp_read_error);
4058 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4059 smtp_get_connection_info(), smtp_read_error);
4067 if (sender_address != NULL)
4069 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4070 US"ETRN is not permitted inside a transaction");
4074 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4075 host_and_ident(FALSE));
4077 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4080 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4084 /* Compute the serialization key for this command. */
4086 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4088 /* If a command has been specified for running as a result of ETRN, we
4089 permit any argument to ETRN. If not, only the # standard form is permitted,
4090 since that is strictly the only kind of ETRN that can be implemented
4091 according to the RFC. */
4093 if (smtp_etrn_command != NULL)
4097 etrn_command = smtp_etrn_command;
4098 deliver_domain = smtp_cmd_data;
4099 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4100 US"ETRN processing", &error);
4101 deliver_domain = NULL;
4104 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4106 smtp_printf("458 Internal failure\r\n");
4111 /* Else set up to call Exim with the -R option. */
4115 if (*smtp_cmd_data++ != '#')
4117 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4118 US"argument must begin with #");
4121 etrn_command = US"exim -R";
4122 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4126 /* If we are host-testing, don't actually do anything. */
4132 debug_printf("ETRN command is: %s\n", etrn_command);
4133 debug_printf("ETRN command execution skipped\n");
4135 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4136 else smtp_user_msg(US"250", user_msg);
4141 /* If ETRN queue runs are to be serialized, check the database to
4142 ensure one isn't already running. */
4144 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4146 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4150 /* Fork a child process and run the command. We don't want to have to
4151 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4152 forking. It should be set that way anyway for external incoming SMTP,
4153 but we save and restore to be tidy. If serialization is required, we
4154 actually run the command in yet another process, so we can wait for it
4155 to complete and then remove the serialization lock. */
4157 oldsignal = signal(SIGCHLD, SIG_IGN);
4159 if ((pid = fork()) == 0)
4161 smtp_input = FALSE; /* This process is not associated with the */
4162 (void)fclose(smtp_in); /* SMTP call any more. */
4163 (void)fclose(smtp_out);
4165 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
4167 /* If not serializing, do the exec right away. Otherwise, fork down
4168 into another process. */
4170 if (!smtp_etrn_serialize || (pid = fork()) == 0)
4172 DEBUG(D_exec) debug_print_argv(argv);
4173 exim_nullstd(); /* Ensure std{in,out,err} exist */
4174 execv(CS argv[0], (char *const *)argv);
4175 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
4176 etrn_command, strerror(errno));
4177 _exit(EXIT_FAILURE); /* paranoia */
4180 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4181 is, we are in the first subprocess, after forking again. All we can do
4182 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4183 complete, before removing the serialization. */
4186 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4187 "failed: %s", strerror(errno));
4191 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4193 (void)wait(&status);
4194 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4198 enq_end(etrn_serialize_key);
4199 _exit(EXIT_SUCCESS);
4202 /* Back in the top level SMTP process. Check that we started a subprocess
4203 and restore the signal state. */
4207 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4209 smtp_printf("458 Unable to fork process\r\n");
4210 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4214 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4215 else smtp_user_msg(US"250", user_msg);
4218 signal(SIGCHLD, oldsignal);
4223 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4224 US"unexpected argument data");
4228 /* This currently happens only for NULLs, but could be extended. */
4231 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
4232 US"NULL character(s) present (shown as '?')");
4233 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
4239 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
4240 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
4241 c = smtp_inend - smtp_inptr;
4242 if (c > 150) c = 150;
4244 incomplete_transaction_log(US"sync failure");
4245 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
4246 "(next input sent too soon: pipelining was%s advertised): "
4247 "rejected \"%s\" %s next input=\"%s\"",
4248 pipelining_advertised? "" : " not",
4249 smtp_cmd_buffer, host_and_ident(TRUE),
4250 string_printing(smtp_inptr));
4251 smtp_notquit_exit(US"synchronization-error", US"554",
4252 US"SMTP synchronization error");
4253 done = 1; /* Pretend eof - drops connection */
4257 case TOO_MANY_NONMAIL_CMD:
4258 s = smtp_cmd_buffer;
4259 while (*s != 0 && !isspace(*s)) s++;
4260 incomplete_transaction_log(US"too many non-mail commands");
4261 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4262 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
4263 s - smtp_cmd_buffer, smtp_cmd_buffer);
4264 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
4265 done = 1; /* Pretend eof - drops connection */
4270 if (unknown_command_count++ >= smtp_max_unknown_commands)
4272 log_write(L_smtp_syntax_error, LOG_MAIN,
4273 "SMTP syntax error in \"%s\" %s %s",
4274 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
4275 US"unrecognized command");
4276 incomplete_transaction_log(US"unrecognized command");
4277 smtp_notquit_exit(US"bad-commands", US"500",
4278 US"Too many unrecognized commands");
4280 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4281 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
4285 done = synprot_error(L_smtp_syntax_error, 500, NULL,
4286 US"unrecognized command");
4290 /* This label is used by goto's inside loops that want to break out to
4291 the end of the command-processing loop. */
4294 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
4295 last_was_rcpt = was_rcpt; /* protocol error handling */
4299 return done - 2; /* Convert yield values */
4302 /* End of smtp_in.c */
git://git.exim.org / exim.git / blob