1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2009 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
14 /* Initialize for TCP wrappers if so configured. It appears that the macro
15 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
16 including that header, and restore its value afterwards. */
18 #ifdef USE_TCP_WRAPPERS
21 #define EXIM_HAVE_IPV6
27 #define HAVE_IPV6 TRUE
30 int allow_severity = LOG_INFO;
31 int deny_severity = LOG_NOTICE;
32 uschar *tcp_wrappers_name;
36 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
37 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
38 commands that accept arguments, and this in particular applies to AUTH, where
39 the data can be quite long. */
41 #define smtp_cmd_buffer_size 2048
43 /* Size of buffer for reading SMTP incoming packets */
45 #define in_buffer_size 8192
47 /* Structure for SMTP command list */
54 short int is_mail_cmd;
57 /* Codes for identifying commands. We order them so that those that come first
58 are those for which synchronization is always required. Checking this can help
62 /* These commands are required to be synchronized, i.e. to be the last in a
63 block of commands when pipelining. */
65 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
66 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
67 ETRN_CMD, /* This by analogy with TURN from the RFC */
68 STARTTLS_CMD, /* Required by the STARTTLS RFC */
70 /* This is a dummy to identify the non-sync commands when pipelining */
72 NON_SYNC_CMD_PIPELINING,
74 /* These commands need not be synchronized when pipelining */
76 MAIL_CMD, RCPT_CMD, RSET_CMD,
78 /* This is a dummy to identify the non-sync commands when not pipelining */
80 NON_SYNC_CMD_NON_PIPELINING,
82 /* I have been unable to find a statement about the use of pipelining
83 with AUTH, so to be on the safe side it is here, though I kind of feel
84 it should be up there with the synchronized commands. */
88 /* I'm not sure about these, but I don't think they matter. */
92 /* These are specials that don't correspond to actual commands */
94 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
95 TOO_MANY_NONMAIL_CMD };
98 /* This is a convenience macro for adding the identity of an SMTP command
99 to the circular buffer that holds a list of the last n received. */
102 smtp_connection_had[smtp_ch_index++] = n; \
103 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
106 /*************************************************
107 * Local static variables *
108 *************************************************/
110 static auth_instance *authenticated_by;
111 static BOOL auth_advertised;
113 static BOOL tls_advertised;
116 static BOOL helo_required = FALSE;
117 static BOOL helo_verify = FALSE;
118 static BOOL helo_seen;
119 static BOOL helo_accept_junk;
120 static BOOL count_nonmail;
121 static BOOL pipelining_advertised;
122 static BOOL rcpt_smtp_response_same;
123 static BOOL rcpt_in_progress;
124 static int nonmail_command_count;
125 static BOOL smtp_exit_function_called = 0;
126 static int synprot_error_count;
127 static int unknown_command_count;
128 static int sync_cmd_limit;
129 static int smtp_write_error = 0;
131 static uschar *rcpt_smtp_response;
132 static uschar *smtp_data_buffer;
133 static uschar *smtp_cmd_data;
135 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
136 final fields of all except AUTH are forced TRUE at the start of a new message
137 setup, to allow one of each between messages that is not counted as a nonmail
138 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
139 allow a new EHLO after starting up TLS.
141 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
142 counted. However, the flag is changed when AUTH is received, so that multiple
143 failing AUTHs will eventually hit the limit. After a successful AUTH, another
144 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
145 forced TRUE, to allow for the re-authentication that can happen at that point.
147 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
148 count of non-mail commands and possibly provoke an error. */
150 static smtp_cmd_list cmd_list[] = {
151 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
152 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
153 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
154 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
156 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
159 /* If you change anything above here, also fix the definitions below. */
161 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
162 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
163 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
164 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
165 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
166 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
167 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
168 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
169 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
172 static smtp_cmd_list *cmd_list_end =
173 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
175 #define CMD_LIST_RSET 0
176 #define CMD_LIST_HELO 1
177 #define CMD_LIST_EHLO 2
178 #define CMD_LIST_AUTH 3
179 #define CMD_LIST_STARTTLS 4
181 /* This list of names is used for performing the smtp_no_mail logging action.
182 It must be kept in step with the SCH_xxx enumerations. */
184 static uschar *smtp_names[] =
186 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
187 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
190 static uschar *protocols[] = {
191 US"local-smtp", /* HELO */
192 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
193 US"local-esmtp", /* EHLO */
194 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
195 US"local-esmtpa", /* EHLO->AUTH */
196 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
201 #define pcrpted 1 /* added to pextend or pnormal */
202 #define pauthed 2 /* added to pextend */
203 #define pnlocal 6 /* offset to remove "local" */
205 /* When reading SMTP from a remote host, we have to use our own versions of the
206 C input-reading functions, in order to be able to flush the SMTP output only
207 when about to read more data from the socket. This is the only way to get
208 optimal performance when the client is using pipelining. Flushing for every
209 command causes a separate packet and reply packet each time; saving all the
210 responses up (when pipelining) combines them into one packet and one response.
212 For simplicity, these functions are used for *all* SMTP input, not only when
213 receiving over a socket. However, after setting up a secure socket (SSL), input
214 is read via the OpenSSL library, and another set of functions is used instead
217 These functions are set in the receive_getc etc. variables and called with the
218 same interface as the C functions. However, since there can only ever be
219 one incoming SMTP call, we just use a single buffer and flags. There is no need
220 to implement a complicated private FILE-like structure.*/
222 static uschar *smtp_inbuffer;
223 static uschar *smtp_inptr;
224 static uschar *smtp_inend;
225 static int smtp_had_eof;
226 static int smtp_had_error;
229 /*************************************************
230 * SMTP version of getc() *
231 *************************************************/
233 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
234 it flushes the output, and refills the buffer, with a timeout. The signal
235 handler is set appropriately by the calling function. This function is not used
236 after a connection has negotated itself into an TLS/SSL state.
239 Returns: the next character or EOF
245 if (smtp_inptr >= smtp_inend)
249 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
250 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
255 /* Must put the error text in fixed store, because this might be during
256 header reading, where it releases unused store above the header. */
259 smtp_had_error = save_errno;
260 smtp_read_error = string_copy_malloc(
261 string_sprintf(" (error: %s)", strerror(save_errno)));
263 else smtp_had_eof = 1;
267 dkim_exim_verify_feed(smtp_inbuffer, rc);
269 smtp_inend = smtp_inbuffer + rc;
270 smtp_inptr = smtp_inbuffer;
272 return *smtp_inptr++;
277 /*************************************************
278 * SMTP version of ungetc() *
279 *************************************************/
281 /* Puts a character back in the input buffer. Only ever
287 Returns: the character
293 *(--smtp_inptr) = ch;
300 /*************************************************
301 * SMTP version of feof() *
302 *************************************************/
304 /* Tests for a previous EOF
307 Returns: non-zero if the eof flag is set
319 /*************************************************
320 * SMTP version of ferror() *
321 *************************************************/
323 /* Tests for a previous read error, and returns with errno
324 restored to what it was when the error was detected.
327 Returns: non-zero if the error flag is set
333 errno = smtp_had_error;
334 return smtp_had_error;
339 /*************************************************
340 * Test for characters in the SMTP buffer *
341 *************************************************/
343 /* Used at the end of a message
352 return smtp_inptr < smtp_inend;
357 /*************************************************
358 * Write formatted string to SMTP channel *
359 *************************************************/
361 /* This is a separate function so that we don't have to repeat everything for
362 TLS support or debugging. It is global so that the daemon and the
363 authentication functions can use it. It does not return any error indication,
364 because major problems such as dropped connections won't show up till an output
365 flush for non-TLS connections. The smtp_fflush() function is available for
366 checking that: for convenience, TLS output errors are remembered here so that
367 they are also picked up later by smtp_fflush().
371 ... optional arguments
377 smtp_printf(const char *format, ...)
381 va_start(ap, format);
382 smtp_vprintf(format, ap);
386 /* This is split off so that verify.c:respond_printf() can, in effect, call
387 smtp_printf(), bearing in mind that in C a vararg function can't directly
388 call another vararg function, only a function which accepts a va_list. */
391 smtp_vprintf(const char *format, va_list ap)
395 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
399 void *reset_point = store_get(0);
400 uschar *msg_copy, *cr, *end;
401 msg_copy = string_copy(big_buffer);
402 end = msg_copy + Ustrlen(msg_copy);
403 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
404 memmove(cr, cr + 1, (end--) - cr);
405 debug_printf("SMTP>> %s", msg_copy);
406 store_reset(reset_point);
411 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
412 smtp_closedown(US"Unexpected error");
413 exim_exit(EXIT_FAILURE);
416 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
417 have had the same. Note: this code is also present in smtp_respond(). It would
418 be tidier to have it only in one place, but when it was added, it was easier to
419 do it that way, so as not to have to mess with the code for the RCPT command,
420 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
422 if (rcpt_in_progress)
424 if (rcpt_smtp_response == NULL)
425 rcpt_smtp_response = string_copy(big_buffer);
426 else if (rcpt_smtp_response_same &&
427 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
428 rcpt_smtp_response_same = FALSE;
429 rcpt_in_progress = FALSE;
432 /* Now write the string */
437 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
442 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
447 /*************************************************
448 * Flush SMTP out and check for error *
449 *************************************************/
451 /* This function isn't currently used within Exim (it detects errors when it
452 tries to read the next SMTP input), but is available for use in local_scan().
453 For non-TLS connections, it flushes the output and checks for errors. For
454 TLS-connections, it checks for a previously-detected TLS write error.
457 Returns: 0 for no error; -1 after an error
463 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
464 return smtp_write_error;
469 /*************************************************
470 * SMTP command read timeout *
471 *************************************************/
473 /* Signal handler for timing out incoming SMTP commands. This attempts to
476 Argument: signal number (SIGALRM)
481 command_timeout_handler(int sig)
483 sig = sig; /* Keep picky compilers happy */
484 log_write(L_lost_incoming_connection,
485 LOG_MAIN, "SMTP command timeout on%s connection from %s",
486 (tls_active >= 0)? " TLS" : "",
487 host_and_ident(FALSE));
488 if (smtp_batched_input)
489 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
490 smtp_notquit_exit(US"command-timeout", US"421",
491 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
492 exim_exit(EXIT_FAILURE);
497 /*************************************************
499 *************************************************/
501 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
503 Argument: signal number (SIGTERM)
508 command_sigterm_handler(int sig)
510 sig = sig; /* Keep picky compilers happy */
511 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
512 if (smtp_batched_input)
513 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
514 smtp_notquit_exit(US"signal-exit", US"421",
515 US"%s: Service not available - closing connection", smtp_active_hostname);
516 exim_exit(EXIT_FAILURE);
522 /*************************************************
523 * Read one command line *
524 *************************************************/
526 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
527 There are sites that don't do this, and in any case internal SMTP probably
528 should check only for LF. Consequently, we check here for LF only. The line
529 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
530 an unknown command. The command is read into the global smtp_cmd_buffer so that
531 it is available via $smtp_command.
533 The character reading routine sets up a timeout for each block actually read
534 from the input (which may contain more than one command). We set up a special
535 signal handler that closes down the session on a timeout. Control does not
539 check_sync if TRUE, check synchronization rules if global option is TRUE
541 Returns: a code identifying the command (enumerated above)
545 smtp_read_command(BOOL check_sync)
550 BOOL hadnull = FALSE;
552 os_non_restarting_signal(SIGALRM, command_timeout_handler);
554 while ((c = (receive_getc)()) != '\n' && c != EOF)
556 if (ptr >= smtp_cmd_buffer_size)
558 os_non_restarting_signal(SIGALRM, sigalrm_handler);
566 smtp_cmd_buffer[ptr++] = c;
569 receive_linecount++; /* For BSMTP errors */
570 os_non_restarting_signal(SIGALRM, sigalrm_handler);
572 /* If hit end of file, return pseudo EOF command. Whether we have a
573 part-line already read doesn't matter, since this is an error state. */
575 if (c == EOF) return EOF_CMD;
577 /* Remove any CR and white space at the end of the line, and terminate the
580 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
581 smtp_cmd_buffer[ptr] = 0;
583 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
585 /* NULLs are not allowed in SMTP commands */
587 if (hadnull) return BADCHAR_CMD;
589 /* Scan command list and return identity, having set the data pointer
590 to the start of the actual data characters. Check for SMTP synchronization
593 for (p = cmd_list; p < cmd_list_end; p++)
595 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
596 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
597 smtp_cmd_buffer[p->len] == 0 ||
598 smtp_cmd_buffer[p->len] == ' '))
600 if (smtp_inptr < smtp_inend && /* Outstanding input */
601 p->cmd < sync_cmd_limit && /* Command should sync */
602 check_sync && /* Local flag set */
603 smtp_enforce_sync && /* Global flag set */
604 sender_host_address != NULL && /* Not local input */
605 !sender_host_notsocket) /* Really is a socket */
608 /* The variables $smtp_command and $smtp_command_argument point into the
609 unmodified input buffer. A copy of the latter is taken for actual
610 processing, so that it can be chopped up into separate parts if necessary,
611 for example, when processing a MAIL command options such as SIZE that can
612 follow the sender address. */
614 smtp_cmd_argument = smtp_cmd_buffer + p->len;
615 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
616 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
617 smtp_cmd_data = smtp_data_buffer;
619 /* Count non-mail commands from those hosts that are controlled in this
620 way. The default is all hosts. We don't waste effort checking the list
621 until we get a non-mail command, but then cache the result to save checking
622 again. If there's a DEFER while checking the host, assume it's in the list.
624 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
625 start of each incoming message by fiddling with the value in the table. */
629 if (count_nonmail == TRUE_UNSET) count_nonmail =
630 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
631 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
632 return TOO_MANY_NONMAIL_CMD;
635 /* If there is data for a command that does not expect it, generate the
638 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
642 /* Enforce synchronization for unknown commands */
644 if (smtp_inptr < smtp_inend && /* Outstanding input */
645 check_sync && /* Local flag set */
646 smtp_enforce_sync && /* Global flag set */
647 sender_host_address != NULL && /* Not local input */
648 !sender_host_notsocket) /* Really is a socket */
656 /*************************************************
657 * Recheck synchronization *
658 *************************************************/
660 /* Synchronization checks can never be perfect because a packet may be on its
661 way but not arrived when the check is done. Such checks can in any case only be
662 done when TLS is not in use. Normally, the checks happen when commands are
663 read: Exim ensures that there is no more input in the input buffer. In normal
664 cases, the response to the command will be fast, and there is no further check.
666 However, for some commands an ACL is run, and that can include delays. In those
667 cases, it is useful to do another check on the input just before sending the
668 response. This also applies at the start of a connection. This function does
669 that check by means of the select() function, as long as the facility is not
670 disabled or inappropriate. A failure of select() is ignored.
672 When there is unwanted input, we read it so that it appears in the log of the
676 Returns: TRUE if all is well; FALSE if there is input pending
684 struct timeval tzero;
686 if (!smtp_enforce_sync || sender_host_address == NULL ||
687 sender_host_notsocket || tls_active >= 0)
690 fd = fileno(smtp_in);
695 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
697 if (rc <= 0) return TRUE; /* Not ready to read */
699 if (rc < 0) return TRUE; /* End of file or error */
702 rc = smtp_inend - smtp_inptr;
703 if (rc > 150) rc = 150;
710 /*************************************************
711 * Forced closedown of call *
712 *************************************************/
714 /* This function is called from log.c when Exim is dying because of a serious
715 disaster, and also from some other places. If an incoming non-batched SMTP
716 channel is open, it swallows the rest of the incoming message if in the DATA
717 phase, sends the reply string, and gives an error to all subsequent commands
718 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
722 message SMTP reply string to send, excluding the code
728 smtp_closedown(uschar *message)
730 if (smtp_in == NULL || smtp_batched_input) return;
731 receive_swallow_smtp();
732 smtp_printf("421 %s\r\n", message);
736 switch(smtp_read_command(FALSE))
742 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
747 smtp_printf("250 Reset OK\r\n");
751 smtp_printf("421 %s\r\n", message);
760 /*************************************************
761 * Set up connection info for logging *
762 *************************************************/
764 /* This function is called when logging information about an SMTP connection.
765 It sets up appropriate source information, depending on the type of connection.
766 If sender_fullhost is NULL, we are at a very early stage of the connection;
767 just use the IP address.
770 Returns: a string describing the connection
774 smtp_get_connection_info(void)
776 uschar *hostname = (sender_fullhost == NULL)?
777 sender_host_address : sender_fullhost;
780 return string_sprintf("SMTP connection from %s", hostname);
782 if (sender_host_unknown || sender_host_notsocket)
783 return string_sprintf("SMTP connection from %s", sender_ident);
786 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
788 if ((log_extra_selector & LX_incoming_interface) != 0 &&
789 interface_address != NULL)
790 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
791 interface_address, interface_port);
793 return string_sprintf("SMTP connection from %s", hostname);
798 /*************************************************
799 * Log lack of MAIL if so configured *
800 *************************************************/
802 /* This function is called when an SMTP session ends. If the log selector
803 smtp_no_mail is set, write a log line giving some details of what has happened
811 smtp_log_no_mail(void)
816 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
822 if (sender_host_authenticated != NULL)
824 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
825 if (authenticated_id != NULL)
826 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
830 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_cipher != NULL)
831 s = string_append(s, &size, &ptr, 2, US" X=", tls_cipher);
832 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
834 s = string_append(s, &size, &ptr, 2, US" CV=",
835 tls_certificate_verified? "yes":"no");
836 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_peerdn != NULL)
837 s = string_append(s, &size, &ptr, 3, US" DN=\"",
838 string_printing(tls_peerdn), US"\"");
841 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
842 US" C=..." : US" C=";
843 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
845 if (smtp_connection_had[i] != SCH_NONE)
847 s = string_append(s, &size, &ptr, 2, sep,
848 smtp_names[smtp_connection_had[i]]);
853 for (i = 0; i < smtp_ch_index; i++)
855 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
859 if (s != NULL) s[ptr] = 0; else s = US"";
860 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
861 host_and_ident(FALSE),
862 readconf_printtime(time(NULL) - smtp_connection_start), s);
867 /*************************************************
868 * Check HELO line and set sender_helo_name *
869 *************************************************/
871 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
872 the domain name of the sending host, or an ip literal in square brackets. The
873 arrgument is placed in sender_helo_name, which is in malloc store, because it
874 must persist over multiple incoming messages. If helo_accept_junk is set, this
875 host is permitted to send any old junk (needed for some broken hosts).
876 Otherwise, helo_allow_chars can be used for rogue characters in general
877 (typically people want to let in underscores).
880 s the data portion of the line (already past any white space)
882 Returns: TRUE or FALSE
886 check_helo(uschar *s)
889 uschar *end = s + Ustrlen(s);
890 BOOL yield = helo_accept_junk;
892 /* Discard any previous helo name */
894 if (sender_helo_name != NULL)
896 store_free(sender_helo_name);
897 sender_helo_name = NULL;
900 /* Skip tests if junk is permitted. */
904 /* Allow the new standard form for IPv6 address literals, namely,
905 [IPv6:....], and because someone is bound to use it, allow an equivalent
906 IPv4 form. Allow plain addresses as well. */
913 if (strncmpic(s, US"[IPv6:", 6) == 0)
914 yield = (string_is_ip_address(s+6, NULL) == 6);
915 else if (strncmpic(s, US"[IPv4:", 6) == 0)
916 yield = (string_is_ip_address(s+6, NULL) == 4);
918 yield = (string_is_ip_address(s+1, NULL) != 0);
923 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
924 that have been configured (usually underscore - sigh). */
931 if (!isalnum(*s) && *s != '.' && *s != '-' &&
932 Ustrchr(helo_allow_chars, *s) == NULL)
942 /* Save argument if OK */
944 if (yield) sender_helo_name = string_copy_malloc(start);
952 /*************************************************
953 * Extract SMTP command option *
954 *************************************************/
956 /* This function picks the next option setting off the end of smtp_cmd_data. It
957 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
958 things that can appear there.
961 name point this at the name
962 value point this at the data string
964 Returns: TRUE if found an option
968 extract_option(uschar **name, uschar **value)
971 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
972 while (isspace(*v)) v--;
975 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
976 if (*v != '=') return FALSE;
979 while(isalpha(n[-1])) n--;
981 if (n[-1] != ' ') return FALSE;
994 /*************************************************
995 * Reset for new message *
996 *************************************************/
998 /* This function is called whenever the SMTP session is reset from
999 within either of the setup functions.
1001 Argument: the stacking pool storage reset point
1006 smtp_reset(void *reset_point)
1008 store_reset(reset_point);
1009 recipients_list = NULL;
1010 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1011 raw_recipients_count = recipients_count = recipients_list_max = 0;
1012 message_linecount = 0;
1014 acl_added_headers = NULL;
1015 queue_only_policy = FALSE;
1016 rcpt_smtp_response = NULL;
1017 rcpt_smtp_response_same = TRUE;
1018 rcpt_in_progress = FALSE;
1019 deliver_freeze = FALSE; /* Can be set by ACL */
1020 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1021 fake_response = OK; /* Can be set by ACL */
1022 #ifdef WITH_CONTENT_SCAN
1023 no_mbox_unspool = FALSE; /* Can be set by ACL */
1025 submission_mode = FALSE; /* Can be set by ACL */
1026 suppress_local_fixups = FALSE; /* Can be set by ACL */
1027 active_local_from_check = local_from_check; /* Can be set by ACL */
1028 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1029 sender_address = NULL;
1030 submission_name = NULL; /* Can be set by ACL */
1031 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1032 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1033 sender_verified_list = NULL; /* No senders verified */
1034 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1035 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1036 authenticated_sender = NULL;
1037 #ifdef EXPERIMENTAL_BRIGHTMAIL
1039 bmi_verdicts = NULL;
1041 #ifndef DISABLE_DKIM
1042 dkim_signers = NULL;
1043 dkim_disable_verify = FALSE;
1044 dkim_collect_input = FALSE;
1046 #ifdef EXPERIMENTAL_SPF
1047 spf_header_comment = NULL;
1048 spf_received = NULL;
1050 spf_smtp_comment = NULL;
1052 body_linecount = body_zerocount = 0;
1054 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1055 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1056 /* Note that ratelimiters_conn persists across resets. */
1058 /* Reset message ACL variables */
1062 /* The message body variables use malloc store. They may be set if this is
1063 not the first message in an SMTP session and the previous message caused them
1064 to be referenced in an ACL. */
1066 if (message_body != NULL)
1068 store_free(message_body);
1069 message_body = NULL;
1072 if (message_body_end != NULL)
1074 store_free(message_body_end);
1075 message_body_end = NULL;
1078 /* Warning log messages are also saved in malloc store. They are saved to avoid
1079 repetition in the same message, but it seems right to repeat them for different
1082 while (acl_warn_logged != NULL)
1084 string_item *this = acl_warn_logged;
1085 acl_warn_logged = acl_warn_logged->next;
1094 /*************************************************
1095 * Initialize for incoming batched SMTP message *
1096 *************************************************/
1098 /* This function is called from smtp_setup_msg() in the case when
1099 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1100 of messages in one file with SMTP commands between them. All errors must be
1101 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1102 relevant. After an error on a sender, or an invalid recipient, the remainder
1103 of the message is skipped. The value of received_protocol is already set.
1106 Returns: > 0 message successfully started (reached DATA)
1107 = 0 QUIT read or end of file reached
1108 < 0 should not occur
1112 smtp_setup_batch_msg(void)
1115 void *reset_point = store_get(0);
1117 /* Save the line count at the start of each transaction - single commands
1118 like HELO and RSET count as whole transactions. */
1120 bsmtp_transaction_linecount = receive_linecount;
1122 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1124 smtp_reset(reset_point); /* Reset for start of message */
1126 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1127 value. The values are 2 larger than the required yield of the function. */
1132 uschar *recipient = NULL;
1133 int start, end, sender_domain, recipient_domain;
1135 switch(smtp_read_command(FALSE))
1137 /* The HELO/EHLO commands set sender_address_helo if they have
1138 valid data; otherwise they are ignored, except that they do
1139 a reset of the state. */
1144 check_helo(smtp_cmd_data);
1148 smtp_reset(reset_point);
1149 bsmtp_transaction_linecount = receive_linecount;
1153 /* The MAIL FROM command requires an address as an operand. All we
1154 do here is to parse it for syntactic correctness. The form "<>" is
1155 a special case which converts into an empty string. The start/end
1156 pointers in the original are not used further for this address, as
1157 it is the canonical extracted address which is all that is kept. */
1160 if (sender_address != NULL)
1161 /* The function moan_smtp_batch() does not return. */
1162 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1164 if (smtp_cmd_data[0] == 0)
1165 /* The function moan_smtp_batch() does not return. */
1166 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1168 /* Reset to start of message */
1170 smtp_reset(reset_point);
1172 /* Apply SMTP rewrite */
1174 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1175 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1176 US"", global_rewrite_rules) : smtp_cmd_data;
1178 /* Extract the address; the TRUE flag allows <> as valid */
1181 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1184 if (raw_sender == NULL)
1185 /* The function moan_smtp_batch() does not return. */
1186 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1188 sender_address = string_copy(raw_sender);
1190 /* Qualify unqualified sender addresses if permitted to do so. */
1192 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1194 if (allow_unqualified_sender)
1196 sender_address = rewrite_address_qualify(sender_address, FALSE);
1197 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1198 "and rewritten\n", raw_sender);
1200 /* The function moan_smtp_batch() does not return. */
1201 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1207 /* The RCPT TO command requires an address as an operand. All we do
1208 here is to parse it for syntactic correctness. There may be any number
1209 of RCPT TO commands, specifying multiple senders. We build them all into
1210 a data structure that is in argc/argv format. The start/end values
1211 given by parse_extract_address are not used, as we keep only the
1212 extracted address. */
1215 if (sender_address == NULL)
1216 /* The function moan_smtp_batch() does not return. */
1217 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1219 if (smtp_cmd_data[0] == 0)
1220 /* The function moan_smtp_batch() does not return. */
1221 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1223 /* Check maximum number allowed */
1225 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1226 /* The function moan_smtp_batch() does not return. */
1227 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1228 recipients_max_reject? "552": "452");
1230 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1231 recipient address */
1233 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1234 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1235 global_rewrite_rules) : smtp_cmd_data;
1237 /* rfc821_domains = TRUE; << no longer needed */
1238 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1239 &recipient_domain, FALSE);
1240 /* rfc821_domains = FALSE; << no longer needed */
1242 if (recipient == NULL)
1243 /* The function moan_smtp_batch() does not return. */
1244 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1246 /* If the recipient address is unqualified, qualify it if permitted. Then
1247 add it to the list of recipients. */
1249 if (recipient_domain == 0)
1251 if (allow_unqualified_recipient)
1253 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1255 recipient = rewrite_address_qualify(recipient, TRUE);
1257 /* The function moan_smtp_batch() does not return. */
1258 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1261 receive_add_recipient(recipient, -1);
1265 /* The DATA command is legal only if it follows successful MAIL FROM
1266 and RCPT TO commands. This function is complete when a valid DATA
1267 command is encountered. */
1270 if (sender_address == NULL || recipients_count <= 0)
1272 /* The function moan_smtp_batch() does not return. */
1273 if (sender_address == NULL)
1274 moan_smtp_batch(smtp_cmd_buffer,
1275 "503 MAIL FROM:<sender> command must precede DATA");
1277 moan_smtp_batch(smtp_cmd_buffer,
1278 "503 RCPT TO:<recipient> must precede DATA");
1282 done = 3; /* DATA successfully achieved */
1283 message_ended = END_NOTENDED; /* Indicate in middle of message */
1288 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1295 bsmtp_transaction_linecount = receive_linecount;
1306 /* The function moan_smtp_batch() does not return. */
1307 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1312 /* The function moan_smtp_batch() does not return. */
1313 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1318 /* The function moan_smtp_batch() does not return. */
1319 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1324 return done - 2; /* Convert yield values */
1330 /*************************************************
1331 * Start an SMTP session *
1332 *************************************************/
1334 /* This function is called at the start of an SMTP session. Thereafter,
1335 smtp_setup_msg() is called to initiate each separate message. This
1336 function does host-specific testing, and outputs the banner line.
1339 Returns: FALSE if the session can not continue; something has
1340 gone wrong, or the connection to the host is blocked
1344 smtp_start_session(void)
1348 uschar *user_msg, *log_msg;
1352 smtp_connection_start = time(NULL);
1353 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1354 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1357 /* Default values for certain variables */
1359 helo_seen = esmtp = helo_accept_junk = FALSE;
1360 smtp_mailcmd_count = 0;
1361 count_nonmail = TRUE_UNSET;
1362 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1363 smtp_delay_mail = smtp_rlm_base;
1364 auth_advertised = FALSE;
1365 pipelining_advertised = FALSE;
1366 pipelining_enable = TRUE;
1367 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1368 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1370 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1372 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1373 authentication settings from -oMaa to remain in force. */
1375 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1376 authenticated_by = NULL;
1379 tls_cipher = tls_peerdn = NULL;
1380 tls_advertised = FALSE;
1383 /* Reset ACL connection variables */
1387 /* Allow for trailing 0 in the command and data buffers. */
1389 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1390 if (smtp_cmd_buffer == NULL)
1391 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1392 "malloc() failed for SMTP command buffer");
1393 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1395 /* For batched input, the protocol setting can be overridden from the
1396 command line by a trusted caller. */
1398 if (smtp_batched_input)
1400 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1403 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1404 reset later if any of EHLO/AUTH/STARTTLS are received. */
1408 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1410 /* Set up the buffer for inputting using direct read() calls, and arrange to
1411 call the local functions instead of the standard C ones. */
1413 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1414 if (smtp_inbuffer == NULL)
1415 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1416 receive_getc = smtp_getc;
1417 receive_ungetc = smtp_ungetc;
1418 receive_feof = smtp_feof;
1419 receive_ferror = smtp_ferror;
1420 receive_smtp_buffered = smtp_buffered;
1421 smtp_inptr = smtp_inend = smtp_inbuffer;
1422 smtp_had_eof = smtp_had_error = 0;
1424 /* Set up the message size limit; this may be host-specific */
1426 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1427 if (expand_string_message != NULL)
1429 if (thismessage_size_limit == -1)
1430 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1431 "%s", expand_string_message);
1433 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1434 "%s", expand_string_message);
1435 smtp_closedown(US"Temporary local problem - please try later");
1439 /* When a message is input locally via the -bs or -bS options, sender_host_
1440 unknown is set unless -oMa was used to force an IP address, in which case it
1441 is checked like a real remote connection. When -bs is used from inetd, this
1442 flag is not set, causing the sending host to be checked. The code that deals
1443 with IP source routing (if configured) is never required for -bs or -bS and
1444 the flag sender_host_notsocket is used to suppress it.
1446 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1447 reserve for certain hosts and/or networks. */
1449 if (!sender_host_unknown)
1452 BOOL reserved_host = FALSE;
1454 /* Look up IP options (source routing info) on the socket if this is not an
1455 -oMa "host", and if any are found, log them and drop the connection.
1457 Linux (and others now, see below) is different to everyone else, so there
1458 has to be some conditional compilation here. Versions of Linux before 2.1.15
1459 used a structure whose name was "options". Somebody finally realized that
1460 this name was silly, and it got changed to "ip_options". I use the
1461 newer name here, but there is a fudge in the script that sets up os.h
1462 to define a macro in older Linux systems.
1464 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1465 glibc 2, which has chosen ip_opts for the structure name. This is now
1466 really a glibc thing rather than a Linux thing, so the condition name
1467 has been changed to reflect this. It is relevant also to GNU/Hurd.
1469 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1470 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1471 a special macro defined in the os.h file.
1473 Some DGUX versions on older hardware appear not to support IP options at
1474 all, so there is now a general macro which can be set to cut out this
1477 How to do this properly in IPv6 is not yet known. */
1479 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1481 #ifdef GLIBC_IP_OPTIONS
1482 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1487 #elif defined DARWIN_IP_OPTIONS
1493 if (!host_checking && !sender_host_notsocket)
1496 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1497 struct ip_options *ipopt = store_get(optlen);
1499 struct ip_opts ipoptblock;
1500 struct ip_opts *ipopt = &ipoptblock;
1501 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1503 struct ipoption ipoptblock;
1504 struct ipoption *ipopt = &ipoptblock;
1505 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1508 /* Occasional genuine failures of getsockopt() have been seen - for
1509 example, "reset by peer". Therefore, just log and give up on this
1510 call, unless the error is ENOPROTOOPT. This error is given by systems
1511 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1512 of writing. So for that error, carry on - we just can't do an IP options
1515 DEBUG(D_receive) debug_printf("checking for IP options\n");
1517 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1520 if (errno != ENOPROTOOPT)
1522 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1523 host_and_ident(FALSE), strerror(errno));
1524 smtp_printf("451 SMTP service not available\r\n");
1529 /* Deal with any IP options that are set. On the systems I have looked at,
1530 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1531 more logging data than will fit in big_buffer. Nevertheless, after somebody
1532 questioned this code, I've added in some paranoid checking. */
1534 else if (optlen > 0)
1536 uschar *p = big_buffer;
1537 uschar *pend = big_buffer + big_buffer_size;
1538 uschar *opt, *adptr;
1540 struct in_addr addr;
1543 uschar *optstart = (uschar *)(ipopt->__data);
1545 uschar *optstart = (uschar *)(ipopt->ip_opts);
1547 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1550 DEBUG(D_receive) debug_printf("IP options exist\n");
1552 Ustrcpy(p, "IP options on incoming call:");
1555 for (opt = optstart; opt != NULL &&
1556 opt < (uschar *)(ipopt) + optlen;)
1570 if (!string_format(p, pend-p, " %s [@%s",
1571 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1573 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1575 inet_ntoa(ipopt->ip_dst)))
1577 inet_ntoa(ipopt->ipopt_dst)))
1585 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1587 while (optcount-- > 0)
1589 memcpy(&addr, adptr, sizeof(addr));
1590 if (!string_format(p, pend - p - 1, "%s%s",
1591 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1597 adptr += sizeof(struct in_addr);
1606 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1609 for (i = 0; i < opt[1]; i++)
1611 sprintf(CS p, "%2.2x ", opt[i]);
1622 log_write(0, LOG_MAIN, "%s", big_buffer);
1624 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1626 log_write(0, LOG_MAIN|LOG_REJECT,
1627 "connection from %s refused (IP options)", host_and_ident(FALSE));
1629 smtp_printf("554 SMTP service not available\r\n");
1633 /* Length of options = 0 => there are no options */
1635 else DEBUG(D_receive) debug_printf("no IP options found\n");
1637 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1639 /* Set keep-alive in socket options. The option is on by default. This
1640 setting is an attempt to get rid of some hanging connections that stick in
1641 read() when the remote end (usually a dialup) goes away. */
1643 if (smtp_accept_keepalive && !sender_host_notsocket)
1644 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1646 /* If the current host matches host_lookup, set the name by doing a
1647 reverse lookup. On failure, sender_host_name will be NULL and
1648 host_lookup_failed will be TRUE. This may or may not be serious - optional
1651 if (verify_check_host(&host_lookup) == OK)
1653 (void)host_name_lookup();
1654 host_build_sender_fullhost();
1657 /* Delay this until we have the full name, if it is looked up. */
1659 set_process_info("handling incoming connection from %s",
1660 host_and_ident(FALSE));
1662 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1663 smtps port for use with older style SSL MTAs. */
1666 if (tls_on_connect &&
1667 tls_server_start(tls_require_ciphers,
1668 gnutls_require_mac, gnutls_require_kx, gnutls_require_proto) != OK)
1672 /* Test for explicit connection rejection */
1674 if (verify_check_host(&host_reject_connection) == OK)
1676 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1677 "from %s (host_reject_connection)", host_and_ident(FALSE));
1678 smtp_printf("554 SMTP service not available\r\n");
1682 /* Test with TCP Wrappers if so configured. There is a problem in that
1683 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1684 such as disks dying. In these cases, it is desirable to reject with a 4xx
1685 error instead of a 5xx error. There isn't a "right" way to detect such
1686 problems. The following kludge is used: errno is zeroed before calling
1687 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1688 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1691 #ifdef USE_TCP_WRAPPERS
1693 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
1694 if (tcp_wrappers_name == NULL)
1696 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
1697 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
1698 expand_string_message);
1700 if (!hosts_ctl(tcp_wrappers_name,
1701 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1702 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1703 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1705 if (errno == 0 || errno == ENOENT)
1707 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1708 log_write(L_connection_reject,
1709 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1710 "(tcp wrappers)", host_and_ident(FALSE));
1711 smtp_printf("554 SMTP service not available\r\n");
1715 int save_errno = errno;
1716 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1717 "errno value %d\n", save_errno);
1718 log_write(L_connection_reject,
1719 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1720 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1721 smtp_printf("451 Temporary local problem - please try later\r\n");
1727 /* Check for reserved slots. The value of smtp_accept_count has already been
1728 incremented to include this process. */
1730 if (smtp_accept_max > 0 &&
1731 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
1733 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1735 log_write(L_connection_reject,
1736 LOG_MAIN, "temporarily refused connection from %s: not in "
1737 "reserve list: connected=%d max=%d reserve=%d%s",
1738 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
1739 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1740 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1741 "please try again later\r\n", smtp_active_hostname);
1744 reserved_host = TRUE;
1747 /* If a load level above which only messages from reserved hosts are
1748 accepted is set, check the load. For incoming calls via the daemon, the
1749 check is done in the superior process if there are no reserved hosts, to
1750 save a fork. In all cases, the load average will already be available
1751 in a global variable at this point. */
1753 if (smtp_load_reserve >= 0 &&
1754 load_average > smtp_load_reserve &&
1756 verify_check_host(&smtp_reserve_hosts) != OK)
1758 log_write(L_connection_reject,
1759 LOG_MAIN, "temporarily refused connection from %s: not in "
1760 "reserve list and load average = %.2f", host_and_ident(FALSE),
1761 (double)load_average/1000.0);
1762 smtp_printf("421 %s: Too much load; please try again later\r\n",
1763 smtp_active_hostname);
1767 /* Determine whether unqualified senders or recipients are permitted
1768 for this host. Unfortunately, we have to do this every time, in order to
1769 set the flags so that they can be inspected when considering qualifying
1770 addresses in the headers. For a site that permits no qualification, this
1771 won't take long, however. */
1773 allow_unqualified_sender =
1774 verify_check_host(&sender_unqualified_hosts) == OK;
1776 allow_unqualified_recipient =
1777 verify_check_host(&recipient_unqualified_hosts) == OK;
1779 /* Determine whether HELO/EHLO is required for this host. The requirement
1780 can be hard or soft. */
1782 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1784 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1786 /* Determine whether this hosts is permitted to send syntactic junk
1787 after a HELO or EHLO command. */
1789 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1792 /* For batch SMTP input we are now done. */
1794 if (smtp_batched_input) return TRUE;
1796 /* Run the ACL if it exists */
1799 if (acl_smtp_connect != NULL)
1802 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1806 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1811 /* Output the initial message for a two-way SMTP connection. It may contain
1812 newlines, which then cause a multi-line response to be given. */
1814 code = US"220"; /* Default status code */
1815 esc = US""; /* Default extended status code */
1816 esclen = 0; /* Length of esc */
1818 if (user_msg == NULL)
1820 s = expand_string(smtp_banner);
1822 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1823 "failed: %s", smtp_banner, expand_string_message);
1829 smtp_message_code(&code, &codelen, &s, NULL);
1833 esclen = codelen - 4;
1837 /* Remove any terminating newlines; might as well remove trailing space too */
1840 while (p > s && isspace(p[-1])) p--;
1843 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1844 is all contained in a single IP packet. The original code wrote out the
1845 greeting using several calls to fprint/fputc, and on busy servers this could
1846 cause it to be split over more than one packet - which caused CC:Mail to fall
1847 over when it got the second part of the greeting after sending its first
1848 command. Sigh. To try to avoid this, build the complete greeting message
1849 first, and output it in one fell swoop. This gives a better chance of it
1850 ending up as a single packet. */
1852 ss = store_get(size);
1856 do /* At least once, in case we have an empty string */
1859 uschar *linebreak = Ustrchr(p, '\n');
1860 ss = string_cat(ss, &size, &ptr, code, 3);
1861 if (linebreak == NULL)
1864 ss = string_cat(ss, &size, &ptr, US" ", 1);
1868 len = linebreak - p;
1869 ss = string_cat(ss, &size, &ptr, US"-", 1);
1871 ss = string_cat(ss, &size, &ptr, esc, esclen);
1872 ss = string_cat(ss, &size, &ptr, p, len);
1873 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1875 if (linebreak != NULL) p++;
1879 ss[ptr] = 0; /* string_cat leaves room for this */
1881 /* Before we write the banner, check that there is no input pending, unless
1882 this synchronisation check is disabled. */
1886 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1887 "synchronization error (input sent without waiting for greeting): "
1888 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1889 string_printing(smtp_inptr));
1890 smtp_printf("554 SMTP synchronization error\r\n");
1894 /* Now output the banner */
1896 smtp_printf("%s", ss);
1904 /*************************************************
1905 * Handle SMTP syntax and protocol errors *
1906 *************************************************/
1908 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1909 to do so. Then transmit the error response. The return value depends on the
1910 number of syntax and protocol errors in this SMTP session.
1913 type error type, given as a log flag bit
1914 code response code; <= 0 means don't send a response
1915 data data to reflect in the response (can be NULL)
1916 errmess the error message
1918 Returns: -1 limit of syntax/protocol errors NOT exceeded
1919 +1 limit of syntax/protocol errors IS exceeded
1921 These values fit in with the values of the "done" variable in the main
1922 processing loop in smtp_setup_msg(). */
1925 synprot_error(int type, int code, uschar *data, uschar *errmess)
1929 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1930 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1931 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1933 if (++synprot_error_count > smtp_max_synprot_errors)
1936 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1937 "syntax or protocol errors (last command was \"%s\")",
1938 host_and_ident(FALSE), smtp_cmd_buffer);
1943 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1944 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1946 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1955 /*************************************************
1956 * Log incomplete transactions *
1957 *************************************************/
1959 /* This function is called after a transaction has been aborted by RSET, QUIT,
1960 connection drops or other errors. It logs the envelope information received
1961 so far in order to preserve address verification attempts.
1963 Argument: string to indicate what aborted the transaction
1968 incomplete_transaction_log(uschar *what)
1970 if (sender_address == NULL || /* No transaction in progress */
1971 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1974 /* Build list of recipients for logging */
1976 if (recipients_count > 0)
1979 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1980 for (i = 0; i < recipients_count; i++)
1981 raw_recipients[i] = recipients_list[i].address;
1982 raw_recipients_count = recipients_count;
1985 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1986 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1992 /*************************************************
1993 * Send SMTP response, possibly multiline *
1994 *************************************************/
1996 /* There are, it seems, broken clients out there that cannot handle multiline
1997 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1998 output nothing for non-final calls, and only the first line for anything else.
2001 code SMTP code, may involve extended status codes
2002 codelen length of smtp code; if > 4 there's an ESC
2003 final FALSE if the last line isn't the final line
2004 msg message text, possibly containing newlines
2010 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2015 if (!final && no_multiline_responses) return;
2020 esclen = codelen - 4;
2023 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2024 have had the same. Note: this code is also present in smtp_printf(). It would
2025 be tidier to have it only in one place, but when it was added, it was easier to
2026 do it that way, so as not to have to mess with the code for the RCPT command,
2027 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2029 if (rcpt_in_progress)
2031 if (rcpt_smtp_response == NULL)
2032 rcpt_smtp_response = string_copy(msg);
2033 else if (rcpt_smtp_response_same &&
2034 Ustrcmp(rcpt_smtp_response, msg) != 0)
2035 rcpt_smtp_response_same = FALSE;
2036 rcpt_in_progress = FALSE;
2039 /* Not output the message, splitting it up into multiple lines if necessary. */
2043 uschar *nl = Ustrchr(msg, '\n');
2046 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2049 else if (nl[1] == 0 || no_multiline_responses)
2051 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2052 (int)(nl - msg), msg);
2057 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2059 while (isspace(*msg)) msg++;
2067 /*************************************************
2068 * Parse user SMTP message *
2069 *************************************************/
2071 /* This function allows for user messages overriding the response code details
2072 by providing a suitable response code string at the start of the message
2073 user_msg. Check the message for starting with a response code and optionally an
2074 extended status code. If found, check that the first digit is valid, and if so,
2075 change the code pointer and length to use the replacement. An invalid code
2076 causes a panic log; in this case, if the log messages is the same as the user
2077 message, we must also adjust the value of the log message to show the code that
2078 is actually going to be used (the original one).
2080 This function is global because it is called from receive.c as well as within
2083 Note that the code length returned includes the terminating whitespace
2084 character, which is always included in the regex match.
2087 code SMTP code, may involve extended status codes
2088 codelen length of smtp code; if > 4 there's an ESC
2090 log_msg optional log message, to be adjusted with the new SMTP code
2096 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2101 if (msg == NULL || *msg == NULL) return;
2103 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2104 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2107 if ((*msg)[0] != (*code)[0])
2109 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2110 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2111 if (log_msg != NULL && *log_msg == *msg)
2112 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2117 *codelen = ovector[1]; /* Includes final space */
2119 *msg += ovector[1]; /* Chop the code off the message */
2126 /*************************************************
2127 * Handle an ACL failure *
2128 *************************************************/
2130 /* This function is called when acl_check() fails. As well as calls from within
2131 this module, it is called from receive.c for an ACL after DATA. It sorts out
2132 logging the incident, and sets up the error response. A message containing
2133 newlines is turned into a multiline SMTP response, but for logging, only the
2136 There's a table of default permanent failure response codes to use in
2137 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2138 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2139 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2140 state, because there are broken clients that try VRFY before RCPT. A 5xx
2141 response should be given only when the address is positively known to be
2142 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2145 From Exim 4.63, it is possible to override the response code details by
2146 providing a suitable response code string at the start of the message provided
2147 in user_msg. The code's first digit is checked for validity.
2150 where where the ACL was called from
2152 user_msg a message that can be included in an SMTP response
2153 log_msg a message for logging
2155 Returns: 0 in most cases
2156 2 if the failure code was FAIL_DROP, in which case the
2157 SMTP connection should be dropped (this value fits with the
2158 "done" variable in smtp_setup_msg() below)
2162 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2164 BOOL drop = rc == FAIL_DROP;
2168 uschar *sender_info = US"";
2170 #ifdef WITH_CONTENT_SCAN
2171 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2173 (where == ACL_WHERE_PREDATA)? US"DATA" :
2174 (where == ACL_WHERE_DATA)? US"after DATA" :
2175 (smtp_cmd_data == NULL)?
2176 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2177 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2179 if (drop) rc = FAIL;
2181 /* Set the default SMTP code, and allow a user message to change it. */
2183 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2184 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2186 /* We used to have sender_address here; however, there was a bug that was not
2187 updating sender_address after a rewrite during a verify. When this bug was
2188 fixed, sender_address at this point became the rewritten address. I'm not sure
2189 this is what should be logged, so I've changed to logging the unrewritten
2190 address to retain backward compatibility. */
2192 #ifndef WITH_CONTENT_SCAN
2193 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2195 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2198 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
2199 sender_address_unrewritten : sender_address);
2202 /* If there's been a sender verification failure with a specific message, and
2203 we have not sent a response about it yet, do so now, as a preliminary line for
2204 failures, but not defers. However, always log it for defer, and log it for fail
2205 unless the sender_verify_fail log selector has been turned off. */
2207 if (sender_verified_failed != NULL &&
2208 !testflag(sender_verified_failed, af_sverify_told))
2210 BOOL save_rcpt_in_progress = rcpt_in_progress;
2211 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2213 setflag(sender_verified_failed, af_sverify_told);
2215 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2216 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2217 host_and_ident(TRUE),
2218 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2219 sender_verified_failed->address,
2220 (sender_verified_failed->message == NULL)? US"" :
2221 string_sprintf(": %s", sender_verified_failed->message));
2223 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2224 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2225 testflag(sender_verified_failed, af_verify_pmfail)?
2226 "Postmaster verification failed while checking <%s>\n%s\n"
2227 "Several RFCs state that you are required to have a postmaster\n"
2228 "mailbox for each mail domain. This host does not accept mail\n"
2229 "from domains whose servers reject the postmaster address."
2231 testflag(sender_verified_failed, af_verify_nsfail)?
2232 "Callback setup failed while verifying <%s>\n%s\n"
2233 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2234 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2235 "RFC requirements, and stops you from receiving standard bounce\n"
2236 "messages. This host does not accept mail from domains whose servers\n"
2239 "Verification failed for <%s>\n%s",
2240 sender_verified_failed->address,
2241 sender_verified_failed->user_message));
2243 rcpt_in_progress = save_rcpt_in_progress;
2246 /* Sort out text for logging */
2248 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2249 lognl = Ustrchr(log_msg, '\n');
2250 if (lognl != NULL) *lognl = 0;
2252 /* Send permanent failure response to the command, but the code used isn't
2253 always a 5xx one - see comments at the start of this function. If the original
2254 rc was FAIL_DROP we drop the connection and yield 2. */
2256 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2257 US"Administrative prohibition" : user_msg);
2259 /* Send temporary failure response to the command. Don't give any details,
2260 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2261 verb, and for a header verify when smtp_return_error_details is set.
2263 This conditional logic is all somewhat of a mess because of the odd
2264 interactions between temp_details and return_error_details. One day it should
2265 be re-implemented in a tidier fashion. */
2269 if (acl_temp_details && user_msg != NULL)
2271 if (smtp_return_error_details &&
2272 sender_verified_failed != NULL &&
2273 sender_verified_failed->message != NULL)
2275 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2277 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2280 smtp_respond(smtp_code, codelen, TRUE,
2281 US"Temporary local problem - please try later");
2284 /* Log the incident to the logs that are specified by log_reject_target
2285 (default main, reject). This can be empty to suppress logging of rejections. If
2286 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2287 is closing if required and return 2. */
2289 if (log_reject_target != 0)
2290 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2291 host_and_ident(TRUE),
2292 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2294 if (!drop) return 0;
2296 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2297 smtp_get_connection_info());
2299 /* Run the not-quit ACL, but without any custom messages. This should not be a
2300 problem, because we get here only if some other ACL has issued "drop", and
2301 in that case, *its* custom messages will have been used above. */
2303 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2310 /*************************************************
2311 * Handle SMTP exit when QUIT is not given *
2312 *************************************************/
2314 /* This function provides a logging/statistics hook for when an SMTP connection
2315 is dropped on the floor or the other end goes away. It's a global function
2316 because it's called from receive.c as well as this module. As well as running
2317 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2318 response, either with a custom message from the ACL, or using a default. There
2319 is one case, however, when no message is output - after "drop". In that case,
2320 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2321 passed to this function.
2323 In case things go wrong while processing this function, causing an error that
2324 may re-enter this funtion, there is a recursion check.
2327 reason What $smtp_notquit_reason will be set to in the ACL;
2328 if NULL, the ACL is not run
2329 code The error code to return as part of the response
2330 defaultrespond The default message if there's no user_msg
2336 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2339 uschar *user_msg = NULL;
2340 uschar *log_msg = NULL;
2342 /* Check for recursive acll */
2344 if (smtp_exit_function_called)
2346 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2350 smtp_exit_function_called = TRUE;
2352 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2354 if (acl_smtp_notquit != NULL && reason != NULL)
2356 smtp_notquit_reason = reason;
2357 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2360 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2364 /* Write an SMTP response if we are expected to give one. As the default
2365 responses are all internal, they should always fit in the buffer, but code a
2366 warning, just in case. Note that string_vformat() still leaves a complete
2367 string, even if it is incomplete. */
2369 if (code != NULL && defaultrespond != NULL)
2371 if (user_msg == NULL)
2375 va_start(ap, defaultrespond);
2376 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2377 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2378 smtp_printf("%s %s\r\n", code, buffer);
2382 smtp_respond(code, 3, TRUE, user_msg);
2390 /*************************************************
2391 * Verify HELO argument *
2392 *************************************************/
2394 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2395 matched. It is also called from ACL processing if verify = helo is used and
2396 verification was not previously tried (i.e. helo_try_verify_hosts was not
2397 matched). The result of its processing is to set helo_verified and
2398 helo_verify_failed. These variables should both be FALSE for this function to
2401 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2402 for IPv6 ::ffff: literals.
2405 Returns: TRUE if testing was completed;
2406 FALSE on a temporary failure
2410 smtp_verify_helo(void)
2414 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2417 if (sender_helo_name == NULL)
2419 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2422 /* Deal with the case of -bs without an IP address */
2424 else if (sender_host_address == NULL)
2426 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2427 helo_verified = TRUE;
2430 /* Deal with the more common case when there is a sending IP address */
2432 else if (sender_helo_name[0] == '[')
2434 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2435 Ustrlen(sender_host_address)) == 0;
2440 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2441 helo_verified = Ustrncmp(sender_helo_name + 1,
2442 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2447 { if (helo_verified) debug_printf("matched host address\n"); }
2450 /* Do a reverse lookup if one hasn't already given a positive or negative
2451 response. If that fails, or the name doesn't match, try checking with a forward
2456 if (sender_host_name == NULL && !host_lookup_failed)
2457 yield = host_name_lookup() != DEFER;
2459 /* If a host name is known, check it and all its aliases. */
2461 if (sender_host_name != NULL)
2463 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2467 HDEBUG(D_receive) debug_printf("matched host name\n");
2471 uschar **aliases = sender_host_aliases;
2472 while (*aliases != NULL)
2474 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2475 if (helo_verified) break;
2480 debug_printf("matched alias %s\n", *(--aliases));
2485 /* Final attempt: try a forward lookup of the helo name */
2491 h.name = sender_helo_name;
2495 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2497 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2498 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2503 if (Ustrcmp(hh->address, sender_host_address) == 0)
2505 helo_verified = TRUE;
2507 debug_printf("IP address for %s matches calling address\n",
2517 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2524 /*************************************************
2525 * Send user response message *
2526 *************************************************/
2528 /* This function is passed a default response code and a user message. It calls
2529 smtp_message_code() to check and possibly modify the response code, and then
2530 calls smtp_respond() to transmit the response. I put this into a function
2531 just to avoid a lot of repetition.
2534 code the response code
2535 user_msg the user message
2541 smtp_user_msg(uschar *code, uschar *user_msg)
2544 smtp_message_code(&code, &len, &user_msg, NULL);
2545 smtp_respond(code, len, TRUE, user_msg);
2551 /*************************************************
2552 * Initialize for SMTP incoming message *
2553 *************************************************/
2555 /* This function conducts the initial dialogue at the start of an incoming SMTP
2556 message, and builds a list of recipients. However, if the incoming message
2557 is part of a batch (-bS option) a separate function is called since it would
2558 be messy having tests splattered about all over this function. This function
2559 therefore handles the case where interaction is occurring. The input and output
2560 files are set up in smtp_in and smtp_out.
2562 The global recipients_list is set to point to a vector of recipient_item
2563 blocks, whose number is given by recipients_count. This is extended by the
2564 receive_add_recipient() function. The global variable sender_address is set to
2565 the sender's address. The yield is +1 if a message has been successfully
2566 started, 0 if a QUIT command was encountered or the connection was refused from
2567 the particular host, or -1 if the connection was lost.
2571 Returns: > 0 message successfully started (reached DATA)
2572 = 0 QUIT read or end of file reached or call refused
2577 smtp_setup_msg(void)
2580 BOOL toomany = FALSE;
2581 BOOL discarded = FALSE;
2582 BOOL last_was_rej_mail = FALSE;
2583 BOOL last_was_rcpt = FALSE;
2584 void *reset_point = store_get(0);
2586 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2588 /* Reset for start of new message. We allow one RSET not to be counted as a
2589 nonmail command, for those MTAs that insist on sending it between every
2590 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2591 TLS between messages (an Exim client may do this if it has messages queued up
2592 for the host). Note: we do NOT reset AUTH at this point. */
2594 smtp_reset(reset_point);
2595 message_ended = END_NOTSTARTED;
2597 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2598 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2599 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2601 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2604 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2606 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2608 /* Batched SMTP is handled in a different function. */
2610 if (smtp_batched_input) return smtp_setup_batch_msg();
2612 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2613 value. The values are 2 larger than the required yield of the function. */
2618 uschar *etrn_command;
2619 uschar *etrn_serialize_key;
2621 uschar *log_msg, *smtp_code;
2622 uschar *user_msg = NULL;
2623 uschar *recipient = NULL;
2624 uschar *hello = NULL;
2625 uschar *set_id = NULL;
2627 BOOL was_rej_mail = FALSE;
2628 BOOL was_rcpt = FALSE;
2629 void (*oldsignal)(int);
2631 int start, end, sender_domain, recipient_domain;
2636 switch(smtp_read_command(TRUE))
2638 /* The AUTH command is not permitted to occur inside a transaction, and may
2639 occur successfully only once per connection. Actually, that isn't quite
2640 true. When TLS is started, all previous information about a connection must
2641 be discarded, so a new AUTH is permitted at that time.
2643 AUTH may only be used when it has been advertised. However, it seems that
2644 there are clients that send AUTH when it hasn't been advertised, some of
2645 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2646 So there's a get-out that allows this to happen.
2648 AUTH is initially labelled as a "nonmail command" so that one occurrence
2649 doesn't get counted. We change the label here so that multiple failing
2650 AUTHS will eventually hit the nonmail threshold. */
2654 authentication_failed = TRUE;
2655 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2657 if (!auth_advertised && !allow_auth_unadvertised)
2659 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2660 US"AUTH command used when not advertised");
2663 if (sender_host_authenticated != NULL)
2665 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2666 US"already authenticated");
2669 if (sender_address != NULL)
2671 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2672 US"not permitted in mail transaction");
2678 if (acl_smtp_auth != NULL)
2680 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2683 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2688 /* Find the name of the requested authentication mechanism. */
2691 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
2693 if (!isalnum(c) && c != '-' && c != '_')
2695 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2696 US"invalid character in authentication mechanism name");
2702 /* If not at the end of the line, we must be at white space. Terminate the
2703 name and move the pointer on to any data that may be present. */
2705 if (*smtp_cmd_data != 0)
2707 *smtp_cmd_data++ = 0;
2708 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
2711 /* Search for an authentication mechanism which is configured for use
2712 as a server and which has been advertised (unless, sigh, allow_auth_
2713 unadvertised is set). */
2715 for (au = auths; au != NULL; au = au->next)
2717 if (strcmpic(s, au->public_name) == 0 && au->server &&
2718 (au->advertised || allow_auth_unadvertised)) break;
2723 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2724 string_sprintf("%s authentication mechanism not supported", s));
2728 /* Run the checking code, passing the remainder of the command line as
2729 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2730 it as the only set numerical variable. The authenticator may set $auth<n>
2731 and also set other numeric variables. The $auth<n> variables are preferred
2732 nowadays; the numerical variables remain for backwards compatibility.
2734 Afterwards, have a go at expanding the set_id string, even if
2735 authentication failed - for bad passwords it can be useful to log the
2736 userid. On success, require set_id to expand and exist, and put it in
2737 authenticated_id. Save this in permanent store, as the working store gets
2738 reset at HELO, RSET, etc. */
2740 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2742 expand_nlength[0] = 0; /* $0 contains nothing */
2744 c = (au->info->servercode)(au, smtp_cmd_data);
2745 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2746 expand_nmax = -1; /* Reset numeric variables */
2747 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2749 /* The value of authenticated_id is stored in the spool file and printed in
2750 log lines. It must not contain binary zeros or newline characters. In
2751 normal use, it never will, but when playing around or testing, this error
2752 can (did) happen. To guard against this, ensure that the id contains only
2753 printing characters. */
2755 if (set_id != NULL) set_id = string_printing(set_id);
2757 /* For the non-OK cases, set up additional logging data if set_id
2762 if (set_id != NULL && *set_id != 0)
2763 set_id = string_sprintf(" (set_id=%s)", set_id);
2767 /* Switch on the result */
2772 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2774 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2775 sender_host_authenticated = au->name;
2776 authentication_failed = FALSE;
2778 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2779 ((sender_host_address != NULL)? pnlocal : 0);
2780 s = ss = US"235 Authentication succeeded";
2781 authenticated_by = au;
2785 /* Authentication succeeded, but we failed to expand the set_id string.
2786 Treat this as a temporary error. */
2788 auth_defer_msg = expand_string_message;
2792 s = string_sprintf("435 Unable to authenticate at present%s",
2793 auth_defer_user_msg);
2794 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2795 set_id, auth_defer_msg);
2799 s = ss = US"501 Invalid base64 data";
2803 s = ss = US"501 Authentication cancelled";
2807 s = ss = US"553 Initial data not expected";
2811 s = US"535 Incorrect authentication data";
2812 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2816 s = US"435 Internal error";
2817 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2818 "check", set_id, c);
2822 smtp_printf("%s\r\n", s);
2824 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2825 au->name, host_and_ident(FALSE), ss);
2827 break; /* AUTH_CMD */
2829 /* The HELO/EHLO commands are permitted to appear in the middle of a
2830 session as well as at the beginning. They have the effect of a reset in
2831 addition to their other functions. Their absence at the start cannot be
2832 taken to be an error.
2836 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2837 or 502 failure replies MUST be returned as appropriate. The SMTP
2838 server MUST stay in the same state after transmitting these replies
2839 that it was in before the EHLO was received.
2841 Therefore, we do not do the reset until after checking the command for
2842 acceptability. This change was made for Exim release 4.11. Previously
2843 it did the reset first. */
2856 HELO_EHLO: /* Common code for HELO and EHLO */
2857 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2858 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2860 /* Reject the HELO if its argument was invalid or non-existent. A
2861 successful check causes the argument to be saved in malloc store. */
2863 if (!check_helo(smtp_cmd_data))
2865 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2867 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2868 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2869 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2870 string_printing(smtp_cmd_argument));
2872 if (++synprot_error_count > smtp_max_synprot_errors)
2874 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2875 "syntax or protocol errors (last command was \"%s\")",
2876 host_and_ident(FALSE), smtp_cmd_buffer);
2883 /* If sender_host_unknown is true, we have got here via the -bs interface,
2884 not called from inetd. Otherwise, we are running an IP connection and the
2885 host address will be set. If the helo name is the primary name of this
2886 host and we haven't done a reverse lookup, force one now. If helo_required
2887 is set, ensure that the HELO name matches the actual host. If helo_verify
2888 is set, do the same check, but softly. */
2890 if (!sender_host_unknown)
2892 BOOL old_helo_verified = helo_verified;
2893 uschar *p = smtp_cmd_data;
2895 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2898 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2899 because otherwise the log can be confusing. */
2901 if (sender_host_name == NULL &&
2902 (deliver_domain = sender_helo_name, /* set $domain */
2903 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2904 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2905 (void)host_name_lookup();
2907 /* Rebuild the fullhost info to include the HELO name (and the real name
2908 if it was looked up.) */
2910 host_build_sender_fullhost(); /* Rebuild */
2911 set_process_info("handling%s incoming connection from %s",
2912 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2914 /* Verify if configured. This doesn't give much security, but it does
2915 make some people happy to be able to do it. If helo_required is set,
2916 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2917 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2918 now obsolescent, since the verification can now be requested selectively
2921 helo_verified = helo_verify_failed = FALSE;
2922 if (helo_required || helo_verify)
2924 BOOL tempfail = !smtp_verify_helo();
2929 smtp_printf("%d %s argument does not match calling host\r\n",
2930 tempfail? 451 : 550, hello);
2931 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2932 tempfail? "temporarily " : "",
2933 hello, sender_helo_name, host_and_ident(FALSE));
2934 helo_verified = old_helo_verified;
2935 break; /* End of HELO/EHLO processing */
2937 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2938 "helo_try_verify_hosts\n", hello);
2943 #ifdef EXPERIMENTAL_SPF
2944 /* set up SPF context */
2945 spf_init(sender_helo_name, sender_host_address);
2948 /* Apply an ACL check if one is defined; afterwards, recheck
2949 synchronization in case the client started sending in a delay. */
2951 if (acl_smtp_helo != NULL)
2953 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2956 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2957 sender_helo_name = NULL;
2958 host_build_sender_fullhost(); /* Rebuild */
2961 else if (!check_sync()) goto SYNC_FAILURE;
2964 /* Generate an OK reply. The default string includes the ident if present,
2965 and also the IP address if present. Reflecting back the ident is intended
2966 as a deterrent to mail forgers. For maximum efficiency, and also because
2967 some broken systems expect each response to be in a single packet, arrange
2968 that the entire reply is sent in one write(). */
2970 auth_advertised = FALSE;
2971 pipelining_advertised = FALSE;
2973 tls_advertised = FALSE;
2976 smtp_code = US"250 "; /* Default response code plus space*/
2977 if (user_msg == NULL)
2979 s = string_sprintf("%.3s %s Hello %s%s%s",
2981 smtp_active_hostname,
2982 (sender_ident == NULL)? US"" : sender_ident,
2983 (sender_ident == NULL)? US"" : US" at ",
2984 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2989 if (sender_host_address != NULL)
2991 s = string_cat(s, &size, &ptr, US" [", 2);
2992 s = string_cat(s, &size, &ptr, sender_host_address,
2993 Ustrlen(sender_host_address));
2994 s = string_cat(s, &size, &ptr, US"]", 1);
2998 /* A user-supplied EHLO greeting may not contain more than one line. Note
2999 that the code returned by smtp_message_code() includes the terminating
3000 whitespace character. */
3006 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3007 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3008 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3010 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3011 "newlines: message truncated: %s", string_printing(s));
3018 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3020 /* If we received EHLO, we must create a multiline response which includes
3021 the functions supported. */
3027 /* I'm not entirely happy with this, as an MTA is supposed to check
3028 that it has enough room to accept a message of maximum size before
3029 it sends this. However, there seems little point in not sending it.
3030 The actual size check happens later at MAIL FROM time. By postponing it
3031 till then, VRFY and EXPN can be used after EHLO when space is short. */
3033 if (thismessage_size_limit > 0)
3035 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3036 thismessage_size_limit);
3037 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3041 s = string_cat(s, &size, &ptr, smtp_code, 3);
3042 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3045 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3046 clean; if it has an 8-bit character in its hand, it just sends it. It
3047 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3048 However, some users want this option simply in order to stop MUAs
3049 mangling messages that contain top-bit-set characters. It is therefore
3050 provided as an option. */
3052 if (accept_8bitmime)
3054 s = string_cat(s, &size, &ptr, smtp_code, 3);
3055 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3058 /* Advertise ETRN if there's an ACL checking whether a host is
3059 permitted to issue it; a check is made when any host actually tries. */
3061 if (acl_smtp_etrn != NULL)
3063 s = string_cat(s, &size, &ptr, smtp_code, 3);
3064 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3067 /* Advertise EXPN if there's an ACL checking whether a host is
3068 permitted to issue it; a check is made when any host actually tries. */
3070 if (acl_smtp_expn != NULL)
3072 s = string_cat(s, &size, &ptr, smtp_code, 3);
3073 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3076 /* Exim is quite happy with pipelining, so let the other end know that
3077 it is safe to use it, unless advertising is disabled. */
3079 if (pipelining_enable &&
3080 verify_check_host(&pipelining_advertise_hosts) == OK)
3082 s = string_cat(s, &size, &ptr, smtp_code, 3);
3083 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3084 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3085 pipelining_advertised = TRUE;
3088 /* If any server authentication mechanisms are configured, advertise
3089 them if the current host is in auth_advertise_hosts. The problem with
3090 advertising always is that some clients then require users to
3091 authenticate (and aren't configurable otherwise) even though it may not
3092 be necessary (e.g. if the host is in host_accept_relay).
3094 RFC 2222 states that SASL mechanism names contain only upper case
3095 letters, so output the names in upper case, though we actually recognize
3096 them in either case in the AUTH command. */
3100 if (verify_check_host(&auth_advertise_hosts) == OK)
3104 for (au = auths; au != NULL; au = au->next)
3106 if (au->server && (au->advertise_condition == NULL ||
3107 expand_check_condition(au->advertise_condition, au->name,
3108 US"authenticator")))
3113 s = string_cat(s, &size, &ptr, smtp_code, 3);
3114 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3116 auth_advertised = TRUE;
3119 s = string_cat(s, &size, &ptr, US" ", 1);
3120 s = string_cat(s, &size, &ptr, au->public_name,
3121 Ustrlen(au->public_name));
3122 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3123 au->advertised = TRUE;
3125 else au->advertised = FALSE;
3127 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3131 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3132 if it has been included in the binary, and the host matches
3133 tls_advertise_hosts. We must *not* advertise if we are already in a
3134 secure connection. */
3137 if (tls_active < 0 &&
3138 verify_check_host(&tls_advertise_hosts) != FAIL)
3140 s = string_cat(s, &size, &ptr, smtp_code, 3);
3141 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3142 tls_advertised = TRUE;
3146 /* Finish off the multiline reply with one that is always available. */
3148 s = string_cat(s, &size, &ptr, smtp_code, 3);
3149 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3152 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3158 if (tls_active >= 0) (void)tls_write(s, ptr); else
3161 (void)fwrite(s, 1, ptr, smtp_out);
3165 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3166 memmove(cr, cr + 1, (ptr--) - (cr - s));
3167 debug_printf("SMTP>> %s", s);
3171 /* Reset the protocol and the state, abandoning any previous message. */
3173 received_protocol = (esmtp?
3175 ((sender_host_authenticated != NULL)? pauthed : 0) +
3176 ((tls_active >= 0)? pcrpted : 0)]
3178 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
3180 ((sender_host_address != NULL)? pnlocal : 0);
3182 smtp_reset(reset_point);
3184 break; /* HELO/EHLO */
3187 /* The MAIL command requires an address as an operand. All we do
3188 here is to parse it for syntactic correctness. The form "<>" is
3189 a special case which converts into an empty string. The start/end
3190 pointers in the original are not used further for this address, as
3191 it is the canonical extracted address which is all that is kept. */
3195 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3196 was_rej_mail = TRUE; /* Reset if accepted */
3198 if (helo_required && !helo_seen)
3200 smtp_printf("503 HELO or EHLO required\r\n");
3201 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3202 "HELO/EHLO given", host_and_ident(FALSE));
3206 if (sender_address != NULL)
3208 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3209 US"sender already given");
3213 if (smtp_cmd_data[0] == 0)
3215 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3216 US"MAIL must have an address operand");
3220 /* Check to see if the limit for messages per connection would be
3221 exceeded by accepting further messages. */
3223 if (smtp_accept_max_per_connection > 0 &&
3224 smtp_mailcmd_count > smtp_accept_max_per_connection)
3226 smtp_printf("421 too many messages in this connection\r\n");
3227 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3228 "messages in one connection", host_and_ident(TRUE));
3232 /* Reset for start of message - even if this is going to fail, we
3233 obviously need to throw away any previous data. */
3235 smtp_reset(reset_point);
3237 sender_data = recipient_data = NULL;
3239 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3243 uschar *name, *value, *end;
3244 unsigned long int size;
3246 if (!extract_option(&name, &value)) break;
3248 /* Handle SIZE= by reading the value. We don't do the check till later,
3249 in order to be able to log the sender address on failure. */
3251 if (strcmpic(name, US"SIZE") == 0 &&
3252 ((size = Ustrtoul(value, &end, 10)), *end == 0))
3254 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3256 message_size = (int)size;
3259 /* If this session was initiated with EHLO and accept_8bitmime is set,
3260 Exim will have indicated that it supports the BODY=8BITMIME option. In
3261 fact, it does not support this according to the RFCs, in that it does not
3262 take any special action for forwarding messages containing 8-bit
3263 characters. That is why accept_8bitmime is not the default setting, but
3264 some sites want the action that is provided. We recognize both "8BITMIME"
3265 and "7BIT" as body types, but take no action. */
3267 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
3268 (strcmpic(value, US"8BITMIME") == 0 ||
3269 strcmpic(value, US"7BIT") == 0)) {}
3271 /* Handle the AUTH extension. If the value given is not "<>" and either
3272 the ACL says "yes" or there is no ACL but the sending host is
3273 authenticated, we set it up as the authenticated sender. However, if the
3274 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3275 the condition is met. The value of AUTH is an xtext, which means that +,
3276 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3279 else if (strcmpic(name, US"AUTH") == 0)
3281 if (Ustrcmp(value, "<>") != 0)
3286 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3288 /* Put back terminator overrides for error message */
3291 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3292 US"invalid data for AUTH");
3296 if (acl_smtp_mailauth == NULL)
3298 ignore_msg = US"client not authenticated";
3299 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3303 ignore_msg = US"rejected by ACL";
3304 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3305 &user_msg, &log_msg);
3311 if (authenticated_by == NULL ||
3312 authenticated_by->mail_auth_condition == NULL ||
3313 expand_check_condition(authenticated_by->mail_auth_condition,
3314 authenticated_by->name, US"authenticator"))
3315 break; /* Accept the AUTH */
3317 ignore_msg = US"server_mail_auth_condition failed";
3318 if (authenticated_id != NULL)
3319 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3320 ignore_msg, authenticated_id);
3325 authenticated_sender = NULL;
3326 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3327 value, host_and_ident(TRUE), ignore_msg);
3330 /* Should only get DEFER or ERROR here. Put back terminator
3331 overrides for error message */
3336 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3343 /* Unknown option. Stick back the terminator characters and break
3344 the loop. An error for a malformed address will occur. */
3354 /* If we have passed the threshold for rate limiting, apply the current
3355 delay, and update it for next time, provided this is a limited host. */
3357 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3358 verify_check_host(&smtp_ratelimit_hosts) == OK)
3360 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3361 smtp_delay_mail/1000.0);
3362 millisleep((int)smtp_delay_mail);
3363 smtp_delay_mail *= smtp_rlm_factor;
3364 if (smtp_delay_mail > (double)smtp_rlm_limit)
3365 smtp_delay_mail = (double)smtp_rlm_limit;
3368 /* Now extract the address, first applying any SMTP-time rewriting. The
3369 TRUE flag allows "<>" as a sender address. */
3371 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3372 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3373 global_rewrite_rules) : smtp_cmd_data;
3375 /* rfc821_domains = TRUE; << no longer needed */
3377 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3379 /* rfc821_domains = FALSE; << no longer needed */
3381 if (raw_sender == NULL)
3383 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3387 sender_address = raw_sender;
3389 /* If there is a configured size limit for mail, check that this message
3390 doesn't exceed it. The check is postponed to this point so that the sender
3393 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3395 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3396 log_write(L_size_reject,
3397 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3398 "message too big: size%s=%d max=%d",
3400 host_and_ident(TRUE),
3401 (message_size == INT_MAX)? ">" : "",
3403 thismessage_size_limit);
3404 sender_address = NULL;
3408 /* Check there is enough space on the disk unless configured not to.
3409 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3410 plus the current message - i.e. we accept the message only if it won't
3411 reduce the space below the threshold. Add 5000 to the size to allow for
3412 overheads such as the Received: line and storing of recipients, etc.
3413 By putting the check here, even when SIZE is not given, it allow VRFY
3414 and EXPN etc. to be used when space is short. */
3416 if (!receive_check_fs(
3417 (smtp_check_spool_space && message_size >= 0)?
3418 message_size + 5000 : 0))
3420 smtp_printf("452 Space shortage, please try later\r\n");
3421 sender_address = NULL;
3425 /* If sender_address is unqualified, reject it, unless this is a locally
3426 generated message, or the sending host or net is permitted to send
3427 unqualified addresses - typically local machines behaving as MUAs -
3428 in which case just qualify the address. The flag is set above at the start
3429 of the SMTP connection. */
3431 if (sender_domain == 0 && sender_address[0] != 0)
3433 if (allow_unqualified_sender)
3435 sender_domain = Ustrlen(sender_address) + 1;
3436 sender_address = rewrite_address_qualify(sender_address, FALSE);
3437 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3442 smtp_printf("501 %s: sender address must contain a domain\r\n",
3444 log_write(L_smtp_syntax_error,
3445 LOG_MAIN|LOG_REJECT,
3446 "unqualified sender rejected: <%s> %s%s",
3448 host_and_ident(TRUE),
3450 sender_address = NULL;
3455 /* Apply an ACL check if one is defined, before responding. Afterwards,
3456 when pipelining is not advertised, do another sync check in case the ACL
3457 delayed and the client started sending in the meantime. */
3459 if (acl_smtp_mail == NULL) rc = OK; else
3461 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3462 if (rc == OK && !pipelining_advertised && !check_sync())
3466 if (rc == OK || rc == DISCARD)
3468 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3469 else smtp_user_msg(US"250", user_msg);
3470 smtp_delay_rcpt = smtp_rlr_base;
3471 recipients_discarded = (rc == DISCARD);
3472 was_rej_mail = FALSE;
3476 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3477 sender_address = NULL;
3482 /* The RCPT command requires an address as an operand. There may be any
3483 number of RCPT commands, specifying multiple recipients. We build them all
3484 into a data structure. The start/end values given by parse_extract_address
3485 are not used, as we keep only the extracted address. */
3490 was_rcpt = rcpt_in_progress = TRUE;
3492 /* There must be a sender address; if the sender was rejected and
3493 pipelining was advertised, we assume the client was pipelining, and do not
3494 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3495 get the same treatment. */
3497 if (sender_address == NULL)
3499 if (pipelining_advertised && last_was_rej_mail)
3501 smtp_printf("503 sender not yet given\r\n");
3502 was_rej_mail = TRUE;
3506 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3507 US"sender not yet given");
3508 was_rcpt = FALSE; /* Not a valid RCPT */
3514 /* Check for an operand */
3516 if (smtp_cmd_data[0] == 0)
3518 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3519 US"RCPT must have an address operand");
3524 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3525 as a recipient address */
3527 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3528 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3529 global_rewrite_rules) : smtp_cmd_data;
3531 /* rfc821_domains = TRUE; << no longer needed */
3532 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3533 &recipient_domain, FALSE);
3534 /* rfc821_domains = FALSE; << no longer needed */
3536 if (recipient == NULL)
3538 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3543 /* If the recipient address is unqualified, reject it, unless this is a
3544 locally generated message. However, unqualified addresses are permitted
3545 from a configured list of hosts and nets - typically when behaving as
3546 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3547 really. The flag is set at the start of the SMTP connection.
3549 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3550 assumed this meant "reserved local part", but the revision of RFC 821 and
3551 friends now makes it absolutely clear that it means *mailbox*. Consequently
3552 we must always qualify this address, regardless. */
3554 if (recipient_domain == 0)
3556 if (allow_unqualified_recipient ||
3557 strcmpic(recipient, US"postmaster") == 0)
3559 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3561 recipient_domain = Ustrlen(recipient) + 1;
3562 recipient = rewrite_address_qualify(recipient, TRUE);
3567 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3569 log_write(L_smtp_syntax_error,
3570 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3571 "<%s> %s%s", recipient, host_and_ident(TRUE),
3577 /* Check maximum allowed */
3579 if (rcpt_count > recipients_max && recipients_max > 0)
3581 if (recipients_max_reject)
3584 smtp_printf("552 too many recipients\r\n");
3586 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3587 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3592 smtp_printf("452 too many recipients\r\n");
3594 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3595 "temporarily rejected: sender=<%s> %s", sender_address,
3596 host_and_ident(TRUE));
3603 /* If we have passed the threshold for rate limiting, apply the current
3604 delay, and update it for next time, provided this is a limited host. */
3606 if (rcpt_count > smtp_rlr_threshold &&
3607 verify_check_host(&smtp_ratelimit_hosts) == OK)
3609 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3610 smtp_delay_rcpt/1000.0);
3611 millisleep((int)smtp_delay_rcpt);
3612 smtp_delay_rcpt *= smtp_rlr_factor;
3613 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3614 smtp_delay_rcpt = (double)smtp_rlr_limit;
3617 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3618 for them. Otherwise, check the access control list for this recipient. As
3619 there may be a delay in this, re-check for a synchronization error
3620 afterwards, unless pipelining was advertised. */
3622 if (recipients_discarded) rc = DISCARD; else
3624 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
3626 if (rc == OK && !pipelining_advertised && !check_sync())
3630 /* The ACL was happy */
3634 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3635 else smtp_user_msg(US"250", user_msg);
3636 receive_add_recipient(recipient, -1);
3639 /* The recipient was discarded */
3641 else if (rc == DISCARD)
3643 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3644 else smtp_user_msg(US"250", user_msg);
3647 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3648 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3649 (sender_address_unrewritten != NULL)?
3650 sender_address_unrewritten : sender_address,
3651 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3652 (log_msg == NULL)? US"" : US": ",
3653 (log_msg == NULL)? US"" : log_msg);
3656 /* Either the ACL failed the address, or it was deferred. */
3660 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3661 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3666 /* The DATA command is legal only if it follows successful MAIL FROM
3667 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3668 not counted as a protocol error if it follows RCPT (which must have been
3669 rejected if there are no recipients.) This function is complete when a
3670 valid DATA command is encountered.
3672 Note concerning the code used: RFC 2821 says this:
3674 - If there was no MAIL, or no RCPT, command, or all such commands
3675 were rejected, the server MAY return a "command out of sequence"
3676 (503) or "no valid recipients" (554) reply in response to the
3679 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3680 because it is the same whether pipelining is in use or not.
3682 If all the RCPT commands that precede DATA provoked the same error message
3683 (often indicating some kind of system error), it is helpful to include it
3684 with the DATA rejection (an idea suggested by Tony Finch). */
3688 if (!discarded && recipients_count <= 0)
3690 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
3692 uschar *code = US"503";
3693 int len = Ustrlen(rcpt_smtp_response);
3694 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
3696 /* Responses from smtp_printf() will have \r\n on the end */
3697 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
3698 rcpt_smtp_response[len-2] = 0;
3699 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
3701 if (pipelining_advertised && last_was_rcpt)
3702 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
3704 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3705 US"valid RCPT command must precede DATA");
3709 if (toomany && recipients_max_reject)
3711 sender_address = NULL; /* This will allow a new MAIL without RSET */
3712 sender_address_unrewritten = NULL;
3713 smtp_printf("554 Too many recipients\r\n");
3717 /* If there is an ACL, re-check the synchronization afterwards, since the
3718 ACL may have delayed. */
3720 if (acl_smtp_predata == NULL) rc = OK; else
3722 enable_dollar_recipients = TRUE;
3723 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3725 enable_dollar_recipients = FALSE;
3726 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
3731 if (user_msg == NULL)
3732 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3733 else smtp_user_msg(US"354", user_msg);
3735 message_ended = END_NOTENDED; /* Indicate in middle of data */
3738 /* Either the ACL failed the address, or it was deferred. */
3741 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3747 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3749 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3755 /* rfc821_domains = TRUE; << no longer needed */
3756 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
3757 &recipient_domain, FALSE);
3758 /* rfc821_domains = FALSE; << no longer needed */
3760 if (address == NULL)
3761 s = string_sprintf("501 %s", errmess);
3764 address_item *addr = deliver_make_addr(address, FALSE);
3765 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3766 -1, -1, NULL, NULL, NULL))
3769 s = string_sprintf("250 <%s> is deliverable", address);
3773 s = (addr->user_message != NULL)?
3774 string_sprintf("451 <%s> %s", address, addr->user_message) :
3775 string_sprintf("451 Cannot resolve <%s> at this time", address);
3779 s = (addr->user_message != NULL)?
3780 string_sprintf("550 <%s> %s", address, addr->user_message) :
3781 string_sprintf("550 <%s> is not deliverable", address);
3782 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3783 smtp_cmd_argument, host_and_ident(TRUE));
3788 smtp_printf("%s\r\n", s);
3795 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3797 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3800 BOOL save_log_testing_mode = log_testing_mode;
3801 address_test_mode = log_testing_mode = TRUE;
3802 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
3803 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3805 address_test_mode = FALSE;
3806 log_testing_mode = save_log_testing_mode; /* true for -bh */
3815 if (!tls_advertised)
3817 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3818 US"STARTTLS command used when not advertised");
3822 /* Apply an ACL check if one is defined */
3824 if (acl_smtp_starttls != NULL)
3826 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3830 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3835 /* RFC 2487 is not clear on when this command may be sent, though it
3836 does state that all information previously obtained from the client
3837 must be discarded if a TLS session is started. It seems reasonble to
3838 do an implied RSET when STARTTLS is received. */
3840 incomplete_transaction_log(US"STARTTLS");
3841 smtp_reset(reset_point);
3843 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3845 /* There's an attack where more data is read in past the STARTTLS command
3846 before TLS is negotiated, then assumed to be part of the secure session
3847 when used afterwards; we use segregated input buffers, so are not
3848 vulnerable, but we want to note when it happens and, for sheer paranoia,
3849 ensure that the buffer is "wiped".
3850 Pipelining sync checks will normally have protected us too, unless disabled
3851 by configuration. */
3853 if (receive_smtp_buffered())
3856 debug_printf("Non-empty input buffer after STARTTLS; naive attack?");
3858 smtp_inend = smtp_inptr = smtp_inbuffer;
3859 /* and if TLS is already active, tls_server_start() should fail */
3862 /* There is nothing we value in the input buffer and if TLS is succesfully
3863 negotiated, we won't use this buffer again; if TLS fails, we'll just read
3864 fresh content into it. The buffer contains arbitrary content from an
3865 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
3866 It seems safest to just wipe away the content rather than leave it as a
3867 target to jump to. */
3869 memset(smtp_inbuffer, 0, in_buffer_size);
3871 /* Attempt to start up a TLS session, and if successful, discard all
3872 knowledge that was obtained previously. At least, that's what the RFC says,
3873 and that's what happens by default. However, in order to work round YAEB,
3874 there is an option to remember the esmtp state. Sigh.
3876 We must allow for an extra EHLO command and an extra AUTH command after
3877 STARTTLS that don't add to the nonmail command count. */
3879 if ((rc = tls_server_start(tls_require_ciphers, gnutls_require_mac,
3880 gnutls_require_kx, gnutls_require_proto)) == OK)
3882 if (!tls_remember_esmtp)
3883 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3884 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3885 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3886 if (sender_helo_name != NULL)
3888 store_free(sender_helo_name);
3889 sender_helo_name = NULL;
3890 host_build_sender_fullhost(); /* Rebuild */
3891 set_process_info("handling incoming TLS connection from %s",
3892 host_and_ident(FALSE));
3894 received_protocol = (esmtp?
3895 protocols[pextend + pcrpted +
3896 ((sender_host_authenticated != NULL)? pauthed : 0)]
3898 protocols[pnormal + pcrpted])
3900 ((sender_host_address != NULL)? pnlocal : 0);
3902 sender_host_authenticated = NULL;
3903 authenticated_id = NULL;
3904 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3905 DEBUG(D_tls) debug_printf("TLS active\n");
3906 break; /* Successful STARTTLS */
3909 /* Some local configuration problem was discovered before actually trying
3910 to do a TLS handshake; give a temporary error. */
3912 else if (rc == DEFER)
3914 smtp_printf("454 TLS currently unavailable\r\n");
3918 /* Hard failure. Reject everything except QUIT or closed connection. One
3919 cause for failure is a nested STARTTLS, in which case tls_active remains
3920 set, but we must still reject all incoming commands. */
3922 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3925 switch(smtp_read_command(FALSE))
3928 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3929 smtp_get_connection_info());
3930 smtp_notquit_exit(US"tls-failed", NULL, NULL);
3934 /* It is perhaps arguable as to which exit ACL should be called here,
3935 but as it is probably a situtation that almost never arises, it
3936 probably doesn't matter. We choose to call the real QUIT ACL, which in
3937 some sense is perhaps "right". */
3941 if (acl_smtp_quit != NULL)
3943 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
3946 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3949 if (user_msg == NULL)
3950 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3952 smtp_respond(US"221", 3, TRUE, user_msg);
3953 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3954 smtp_get_connection_info());
3959 smtp_printf("554 Security failure\r\n");
3968 /* The ACL for QUIT is provided for gathering statistical information or
3969 similar; it does not affect the response code, but it can supply a custom
3974 incomplete_transaction_log(US"QUIT");
3975 if (acl_smtp_quit != NULL)
3977 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
3979 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3982 if (user_msg == NULL)
3983 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3985 smtp_respond(US"221", 3, TRUE, user_msg);
3992 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3993 smtp_get_connection_info());
3999 incomplete_transaction_log(US"RSET");
4000 smtp_reset(reset_point);
4002 smtp_printf("250 Reset OK\r\n");
4003 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
4009 smtp_printf("250 OK\r\n");
4013 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
4014 used, a check will be done for permitted hosts. Show STARTTLS only if not
4015 already in a TLS session and if it would be advertised in the EHLO
4020 smtp_printf("214-Commands supported:\r\n");
4024 Ustrcat(buffer, " AUTH");
4026 if (tls_active < 0 &&
4027 verify_check_host(&tls_advertise_hosts) != FAIL)
4028 Ustrcat(buffer, " STARTTLS");
4030 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
4031 Ustrcat(buffer, " NOOP QUIT RSET HELP");
4032 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4033 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4034 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4035 smtp_printf("214%s\r\n", buffer);
4041 incomplete_transaction_log(US"connection lost");
4042 smtp_notquit_exit(US"connection-lost", US"421",
4043 US"%s lost input connection", smtp_active_hostname);
4045 /* Don't log by default unless in the middle of a message, as some mailers
4046 just drop the call rather than sending QUIT, and it clutters up the logs.
4049 if (sender_address != NULL || recipients_count > 0)
4050 log_write(L_lost_incoming_connection,
4052 "unexpected %s while reading SMTP command from %s%s",
4053 sender_host_unknown? "EOF" : "disconnection",
4054 host_and_ident(FALSE), smtp_read_error);
4056 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4057 smtp_get_connection_info(), smtp_read_error);
4065 if (sender_address != NULL)
4067 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4068 US"ETRN is not permitted inside a transaction");
4072 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4073 host_and_ident(FALSE));
4075 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4078 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4082 /* Compute the serialization key for this command. */
4084 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4086 /* If a command has been specified for running as a result of ETRN, we
4087 permit any argument to ETRN. If not, only the # standard form is permitted,
4088 since that is strictly the only kind of ETRN that can be implemented
4089 according to the RFC. */
4091 if (smtp_etrn_command != NULL)
4095 etrn_command = smtp_etrn_command;
4096 deliver_domain = smtp_cmd_data;
4097 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4098 US"ETRN processing", &error);
4099 deliver_domain = NULL;
4102 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4104 smtp_printf("458 Internal failure\r\n");
4109 /* Else set up to call Exim with the -R option. */
4113 if (*smtp_cmd_data++ != '#')
4115 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4116 US"argument must begin with #");
4119 etrn_command = US"exim -R";
4120 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4124 /* If we are host-testing, don't actually do anything. */
4130 debug_printf("ETRN command is: %s\n", etrn_command);
4131 debug_printf("ETRN command execution skipped\n");
4133 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4134 else smtp_user_msg(US"250", user_msg);
4139 /* If ETRN queue runs are to be serialized, check the database to
4140 ensure one isn't already running. */
4142 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4144 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4148 /* Fork a child process and run the command. We don't want to have to
4149 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4150 forking. It should be set that way anyway for external incoming SMTP,
4151 but we save and restore to be tidy. If serialization is required, we
4152 actually run the command in yet another process, so we can wait for it
4153 to complete and then remove the serialization lock. */
4155 oldsignal = signal(SIGCHLD, SIG_IGN);
4157 if ((pid = fork()) == 0)
4159 smtp_input = FALSE; /* This process is not associated with the */
4160 (void)fclose(smtp_in); /* SMTP call any more. */
4161 (void)fclose(smtp_out);
4163 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
4165 /* If not serializing, do the exec right away. Otherwise, fork down
4166 into another process. */
4168 if (!smtp_etrn_serialize || (pid = fork()) == 0)
4170 DEBUG(D_exec) debug_print_argv(argv);
4171 exim_nullstd(); /* Ensure std{in,out,err} exist */
4172 execv(CS argv[0], (char *const *)argv);
4173 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
4174 etrn_command, strerror(errno));
4175 _exit(EXIT_FAILURE); /* paranoia */
4178 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4179 is, we are in the first subprocess, after forking again. All we can do
4180 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4181 complete, before removing the serialization. */
4184 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4185 "failed: %s", strerror(errno));
4189 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4191 (void)wait(&status);
4192 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4196 enq_end(etrn_serialize_key);
4197 _exit(EXIT_SUCCESS);
4200 /* Back in the top level SMTP process. Check that we started a subprocess
4201 and restore the signal state. */
4205 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4207 smtp_printf("458 Unable to fork process\r\n");
4208 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4212 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4213 else smtp_user_msg(US"250", user_msg);
4216 signal(SIGCHLD, oldsignal);
4221 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4222 US"unexpected argument data");
4226 /* This currently happens only for NULLs, but could be extended. */
4229 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
4230 US"NULL character(s) present (shown as '?')");
4231 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
4237 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
4238 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
4239 c = smtp_inend - smtp_inptr;
4240 if (c > 150) c = 150;
4242 incomplete_transaction_log(US"sync failure");
4243 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
4244 "(next input sent too soon: pipelining was%s advertised): "
4245 "rejected \"%s\" %s next input=\"%s\"",
4246 pipelining_advertised? "" : " not",
4247 smtp_cmd_buffer, host_and_ident(TRUE),
4248 string_printing(smtp_inptr));
4249 smtp_notquit_exit(US"synchronization-error", US"554",
4250 US"SMTP synchronization error");
4251 done = 1; /* Pretend eof - drops connection */
4255 case TOO_MANY_NONMAIL_CMD:
4256 s = smtp_cmd_buffer;
4257 while (*s != 0 && !isspace(*s)) s++;
4258 incomplete_transaction_log(US"too many non-mail commands");
4259 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4260 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
4261 s - smtp_cmd_buffer, smtp_cmd_buffer);
4262 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
4263 done = 1; /* Pretend eof - drops connection */
4268 if (unknown_command_count++ >= smtp_max_unknown_commands)
4270 log_write(L_smtp_syntax_error, LOG_MAIN,
4271 "SMTP syntax error in \"%s\" %s %s",
4272 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
4273 US"unrecognized command");
4274 incomplete_transaction_log(US"unrecognized command");
4275 smtp_notquit_exit(US"bad-commands", US"500",
4276 US"Too many unrecognized commands");
4278 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4279 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
4283 done = synprot_error(L_smtp_syntax_error, 500, NULL,
4284 US"unrecognized command");
4288 /* This label is used by goto's inside loops that want to break out to
4289 the end of the command-processing loop. */
4292 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
4293 last_was_rcpt = was_rcpt; /* protocol error handling */
4297 return done - 2; /* Convert yield values */
4300 /* End of smtp_in.c */
git://git.exim.org / exim.git / blob