1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.67 2010/06/12 15:21:26 jetmore Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2009 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
34 uschar *tcp_wrappers_name;
38 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
39 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
40 commands that accept arguments, and this in particular applies to AUTH, where
41 the data can be quite long. */
43 #define smtp_cmd_buffer_size 2048
45 /* Size of buffer for reading SMTP incoming packets */
47 #define in_buffer_size 8192
49 /* Structure for SMTP command list */
56 short int is_mail_cmd;
59 /* Codes for identifying commands. We order them so that those that come first
60 are those for which synchronization is always required. Checking this can help
64 /* These commands are required to be synchronized, i.e. to be the last in a
65 block of commands when pipelining. */
67 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
68 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
69 ETRN_CMD, /* This by analogy with TURN from the RFC */
70 STARTTLS_CMD, /* Required by the STARTTLS RFC */
72 /* This is a dummy to identify the non-sync commands when pipelining */
74 NON_SYNC_CMD_PIPELINING,
76 /* These commands need not be synchronized when pipelining */
78 MAIL_CMD, RCPT_CMD, RSET_CMD,
80 /* This is a dummy to identify the non-sync commands when not pipelining */
82 NON_SYNC_CMD_NON_PIPELINING,
84 /* I have been unable to find a statement about the use of pipelining
85 with AUTH, so to be on the safe side it is here, though I kind of feel
86 it should be up there with the synchronized commands. */
90 /* I'm not sure about these, but I don't think they matter. */
94 /* These are specials that don't correspond to actual commands */
96 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
97 TOO_MANY_NONMAIL_CMD };
100 /* This is a convenience macro for adding the identity of an SMTP command
101 to the circular buffer that holds a list of the last n received. */
104 smtp_connection_had[smtp_ch_index++] = n; \
105 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
108 /*************************************************
109 * Local static variables *
110 *************************************************/
112 static auth_instance *authenticated_by;
113 static BOOL auth_advertised;
115 static BOOL tls_advertised;
118 static BOOL helo_required = FALSE;
119 static BOOL helo_verify = FALSE;
120 static BOOL helo_seen;
121 static BOOL helo_accept_junk;
122 static BOOL count_nonmail;
123 static BOOL pipelining_advertised;
124 static BOOL rcpt_smtp_response_same;
125 static BOOL rcpt_in_progress;
126 static int nonmail_command_count;
127 static BOOL smtp_exit_function_called = 0;
128 static int synprot_error_count;
129 static int unknown_command_count;
130 static int sync_cmd_limit;
131 static int smtp_write_error = 0;
133 static uschar *rcpt_smtp_response;
134 static uschar *smtp_data_buffer;
135 static uschar *smtp_cmd_data;
137 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
138 final fields of all except AUTH are forced TRUE at the start of a new message
139 setup, to allow one of each between messages that is not counted as a nonmail
140 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
141 allow a new EHLO after starting up TLS.
143 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
144 counted. However, the flag is changed when AUTH is received, so that multiple
145 failing AUTHs will eventually hit the limit. After a successful AUTH, another
146 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
147 forced TRUE, to allow for the re-authentication that can happen at that point.
149 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
150 count of non-mail commands and possibly provoke an error. */
152 static smtp_cmd_list cmd_list[] = {
153 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
154 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
155 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
156 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
158 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
161 /* If you change anything above here, also fix the definitions below. */
163 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
164 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
165 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
166 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
167 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
168 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
169 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
170 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
171 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
174 static smtp_cmd_list *cmd_list_end =
175 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
177 #define CMD_LIST_RSET 0
178 #define CMD_LIST_HELO 1
179 #define CMD_LIST_EHLO 2
180 #define CMD_LIST_AUTH 3
181 #define CMD_LIST_STARTTLS 4
183 /* This list of names is used for performing the smtp_no_mail logging action.
184 It must be kept in step with the SCH_xxx enumerations. */
186 static uschar *smtp_names[] =
188 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
189 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
192 static uschar *protocols[] = {
193 US"local-smtp", /* HELO */
194 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
195 US"local-esmtp", /* EHLO */
196 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
197 US"local-esmtpa", /* EHLO->AUTH */
198 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
203 #define pcrpted 1 /* added to pextend or pnormal */
204 #define pauthed 2 /* added to pextend */
205 #define pnlocal 6 /* offset to remove "local" */
207 /* When reading SMTP from a remote host, we have to use our own versions of the
208 C input-reading functions, in order to be able to flush the SMTP output only
209 when about to read more data from the socket. This is the only way to get
210 optimal performance when the client is using pipelining. Flushing for every
211 command causes a separate packet and reply packet each time; saving all the
212 responses up (when pipelining) combines them into one packet and one response.
214 For simplicity, these functions are used for *all* SMTP input, not only when
215 receiving over a socket. However, after setting up a secure socket (SSL), input
216 is read via the OpenSSL library, and another set of functions is used instead
219 These functions are set in the receive_getc etc. variables and called with the
220 same interface as the C functions. However, since there can only ever be
221 one incoming SMTP call, we just use a single buffer and flags. There is no need
222 to implement a complicated private FILE-like structure.*/
224 static uschar *smtp_inbuffer;
225 static uschar *smtp_inptr;
226 static uschar *smtp_inend;
227 static int smtp_had_eof;
228 static int smtp_had_error;
231 /*************************************************
232 * SMTP version of getc() *
233 *************************************************/
235 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
236 it flushes the output, and refills the buffer, with a timeout. The signal
237 handler is set appropriately by the calling function. This function is not used
238 after a connection has negotated itself into an TLS/SSL state.
241 Returns: the next character or EOF
247 if (smtp_inptr >= smtp_inend)
251 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
252 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
257 /* Must put the error text in fixed store, because this might be during
258 header reading, where it releases unused store above the header. */
261 smtp_had_error = save_errno;
262 smtp_read_error = string_copy_malloc(
263 string_sprintf(" (error: %s)", strerror(save_errno)));
265 else smtp_had_eof = 1;
269 dkim_exim_verify_feed(smtp_inbuffer, rc);
271 smtp_inend = smtp_inbuffer + rc;
272 smtp_inptr = smtp_inbuffer;
274 return *smtp_inptr++;
279 /*************************************************
280 * SMTP version of ungetc() *
281 *************************************************/
283 /* Puts a character back in the input buffer. Only ever
289 Returns: the character
295 *(--smtp_inptr) = ch;
302 /*************************************************
303 * SMTP version of feof() *
304 *************************************************/
306 /* Tests for a previous EOF
309 Returns: non-zero if the eof flag is set
321 /*************************************************
322 * SMTP version of ferror() *
323 *************************************************/
325 /* Tests for a previous read error, and returns with errno
326 restored to what it was when the error was detected.
329 Returns: non-zero if the error flag is set
335 errno = smtp_had_error;
336 return smtp_had_error;
341 /*************************************************
342 * Test for characters in the SMTP buffer *
343 *************************************************/
345 /* Used at the end of a message
354 return smtp_inptr < smtp_inend;
359 /*************************************************
360 * Write formatted string to SMTP channel *
361 *************************************************/
363 /* This is a separate function so that we don't have to repeat everything for
364 TLS support or debugging. It is global so that the daemon and the
365 authentication functions can use it. It does not return any error indication,
366 because major problems such as dropped connections won't show up till an output
367 flush for non-TLS connections. The smtp_fflush() function is available for
368 checking that: for convenience, TLS output errors are remembered here so that
369 they are also picked up later by smtp_fflush().
373 ... optional arguments
379 smtp_printf(char *format, ...)
383 va_start(ap, format);
384 smtp_vprintf(format, ap);
388 /* This is split off so that verify.c:respond_printf() can, in effect, call
389 smtp_printf(), bearing in mind that in C a vararg function can't directly
390 call another vararg function, only a function which accepts a va_list.
392 Note also that repeated calls to va_start()/va_end() pairs is claimed to be
393 non-portable; meanwhile, va_copy() is also non-portable in that it's C99, so
394 we end up needing OS support to define it for us. */
397 smtp_vprintf(char *format, va_list ap)
405 (void) string_vformat(big_buffer, big_buffer_size, format, ap_d);
406 end = big_buffer + Ustrlen(big_buffer);
407 while ((cr = Ustrchr(big_buffer, '\r')) != NULL) /* lose CRs */
408 memmove(cr, cr + 1, (end--) - cr);
409 debug_printf("SMTP>> %s", big_buffer);
412 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
414 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
415 smtp_closedown(US"Unexpected error");
416 exim_exit(EXIT_FAILURE);
419 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
420 have had the same. Note: this code is also present in smtp_respond(). It would
421 be tidier to have it only in one place, but when it was added, it was easier to
422 do it that way, so as not to have to mess with the code for the RCPT command,
423 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
425 if (rcpt_in_progress)
427 if (rcpt_smtp_response == NULL)
428 rcpt_smtp_response = string_copy(big_buffer);
429 else if (rcpt_smtp_response_same &&
430 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
431 rcpt_smtp_response_same = FALSE;
432 rcpt_in_progress = FALSE;
435 /* Now write the string */
440 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
445 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
450 /*************************************************
451 * Flush SMTP out and check for error *
452 *************************************************/
454 /* This function isn't currently used within Exim (it detects errors when it
455 tries to read the next SMTP input), but is available for use in local_scan().
456 For non-TLS connections, it flushes the output and checks for errors. For
457 TLS-connections, it checks for a previously-detected TLS write error.
460 Returns: 0 for no error; -1 after an error
466 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
467 return smtp_write_error;
472 /*************************************************
473 * SMTP command read timeout *
474 *************************************************/
476 /* Signal handler for timing out incoming SMTP commands. This attempts to
479 Argument: signal number (SIGALRM)
484 command_timeout_handler(int sig)
486 sig = sig; /* Keep picky compilers happy */
487 log_write(L_lost_incoming_connection,
488 LOG_MAIN, "SMTP command timeout on%s connection from %s",
489 (tls_active >= 0)? " TLS" : "",
490 host_and_ident(FALSE));
491 if (smtp_batched_input)
492 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
493 smtp_notquit_exit(US"command-timeout", US"421",
494 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
495 exim_exit(EXIT_FAILURE);
500 /*************************************************
502 *************************************************/
504 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
506 Argument: signal number (SIGTERM)
511 command_sigterm_handler(int sig)
513 sig = sig; /* Keep picky compilers happy */
514 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
515 if (smtp_batched_input)
516 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
517 smtp_notquit_exit(US"signal-exit", US"421",
518 US"%s: Service not available - closing connection", smtp_active_hostname);
519 exim_exit(EXIT_FAILURE);
525 /*************************************************
526 * Read one command line *
527 *************************************************/
529 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
530 There are sites that don't do this, and in any case internal SMTP probably
531 should check only for LF. Consequently, we check here for LF only. The line
532 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
533 an unknown command. The command is read into the global smtp_cmd_buffer so that
534 it is available via $smtp_command.
536 The character reading routine sets up a timeout for each block actually read
537 from the input (which may contain more than one command). We set up a special
538 signal handler that closes down the session on a timeout. Control does not
542 check_sync if TRUE, check synchronization rules if global option is TRUE
544 Returns: a code identifying the command (enumerated above)
548 smtp_read_command(BOOL check_sync)
553 BOOL hadnull = FALSE;
555 os_non_restarting_signal(SIGALRM, command_timeout_handler);
557 while ((c = (receive_getc)()) != '\n' && c != EOF)
559 if (ptr >= smtp_cmd_buffer_size)
561 os_non_restarting_signal(SIGALRM, sigalrm_handler);
569 smtp_cmd_buffer[ptr++] = c;
572 receive_linecount++; /* For BSMTP errors */
573 os_non_restarting_signal(SIGALRM, sigalrm_handler);
575 /* If hit end of file, return pseudo EOF command. Whether we have a
576 part-line already read doesn't matter, since this is an error state. */
578 if (c == EOF) return EOF_CMD;
580 /* Remove any CR and white space at the end of the line, and terminate the
583 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
584 smtp_cmd_buffer[ptr] = 0;
586 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
588 /* NULLs are not allowed in SMTP commands */
590 if (hadnull) return BADCHAR_CMD;
592 /* Scan command list and return identity, having set the data pointer
593 to the start of the actual data characters. Check for SMTP synchronization
596 for (p = cmd_list; p < cmd_list_end; p++)
598 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
599 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
600 smtp_cmd_buffer[p->len] == 0 ||
601 smtp_cmd_buffer[p->len] == ' '))
603 if (smtp_inptr < smtp_inend && /* Outstanding input */
604 p->cmd < sync_cmd_limit && /* Command should sync */
605 check_sync && /* Local flag set */
606 smtp_enforce_sync && /* Global flag set */
607 sender_host_address != NULL && /* Not local input */
608 !sender_host_notsocket) /* Really is a socket */
611 /* The variables $smtp_command and $smtp_command_argument point into the
612 unmodified input buffer. A copy of the latter is taken for actual
613 processing, so that it can be chopped up into separate parts if necessary,
614 for example, when processing a MAIL command options such as SIZE that can
615 follow the sender address. */
617 smtp_cmd_argument = smtp_cmd_buffer + p->len;
618 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
619 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
620 smtp_cmd_data = smtp_data_buffer;
622 /* Count non-mail commands from those hosts that are controlled in this
623 way. The default is all hosts. We don't waste effort checking the list
624 until we get a non-mail command, but then cache the result to save checking
625 again. If there's a DEFER while checking the host, assume it's in the list.
627 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
628 start of each incoming message by fiddling with the value in the table. */
632 if (count_nonmail == TRUE_UNSET) count_nonmail =
633 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
634 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
635 return TOO_MANY_NONMAIL_CMD;
638 /* If there is data for a command that does not expect it, generate the
641 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
645 /* Enforce synchronization for unknown commands */
647 if (smtp_inptr < smtp_inend && /* Outstanding input */
648 check_sync && /* Local flag set */
649 smtp_enforce_sync && /* Global flag set */
650 sender_host_address != NULL && /* Not local input */
651 !sender_host_notsocket) /* Really is a socket */
659 /*************************************************
660 * Recheck synchronization *
661 *************************************************/
663 /* Synchronization checks can never be perfect because a packet may be on its
664 way but not arrived when the check is done. Such checks can in any case only be
665 done when TLS is not in use. Normally, the checks happen when commands are
666 read: Exim ensures that there is no more input in the input buffer. In normal
667 cases, the response to the command will be fast, and there is no further check.
669 However, for some commands an ACL is run, and that can include delays. In those
670 cases, it is useful to do another check on the input just before sending the
671 response. This also applies at the start of a connection. This function does
672 that check by means of the select() function, as long as the facility is not
673 disabled or inappropriate. A failure of select() is ignored.
675 When there is unwanted input, we read it so that it appears in the log of the
679 Returns: TRUE if all is well; FALSE if there is input pending
687 struct timeval tzero;
689 if (!smtp_enforce_sync || sender_host_address == NULL ||
690 sender_host_notsocket || tls_active >= 0)
693 fd = fileno(smtp_in);
698 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
700 if (rc <= 0) return TRUE; /* Not ready to read */
702 if (rc < 0) return TRUE; /* End of file or error */
705 rc = smtp_inend - smtp_inptr;
706 if (rc > 150) rc = 150;
713 /*************************************************
714 * Forced closedown of call *
715 *************************************************/
717 /* This function is called from log.c when Exim is dying because of a serious
718 disaster, and also from some other places. If an incoming non-batched SMTP
719 channel is open, it swallows the rest of the incoming message if in the DATA
720 phase, sends the reply string, and gives an error to all subsequent commands
721 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
725 message SMTP reply string to send, excluding the code
731 smtp_closedown(uschar *message)
733 if (smtp_in == NULL || smtp_batched_input) return;
734 receive_swallow_smtp();
735 smtp_printf("421 %s\r\n", message);
739 switch(smtp_read_command(FALSE))
745 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
750 smtp_printf("250 Reset OK\r\n");
754 smtp_printf("421 %s\r\n", message);
763 /*************************************************
764 * Set up connection info for logging *
765 *************************************************/
767 /* This function is called when logging information about an SMTP connection.
768 It sets up appropriate source information, depending on the type of connection.
769 If sender_fullhost is NULL, we are at a very early stage of the connection;
770 just use the IP address.
773 Returns: a string describing the connection
777 smtp_get_connection_info(void)
779 uschar *hostname = (sender_fullhost == NULL)?
780 sender_host_address : sender_fullhost;
783 return string_sprintf("SMTP connection from %s", hostname);
785 if (sender_host_unknown || sender_host_notsocket)
786 return string_sprintf("SMTP connection from %s", sender_ident);
789 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
791 if ((log_extra_selector & LX_incoming_interface) != 0 &&
792 interface_address != NULL)
793 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
794 interface_address, interface_port);
796 return string_sprintf("SMTP connection from %s", hostname);
801 /*************************************************
802 * Log lack of MAIL if so configured *
803 *************************************************/
805 /* This function is called when an SMTP session ends. If the log selector
806 smtp_no_mail is set, write a log line giving some details of what has happened
814 smtp_log_no_mail(void)
819 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
825 if (sender_host_authenticated != NULL)
827 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
828 if (authenticated_id != NULL)
829 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
833 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_cipher != NULL)
834 s = string_append(s, &size, &ptr, 2, US" X=", tls_cipher);
835 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
837 s = string_append(s, &size, &ptr, 2, US" CV=",
838 tls_certificate_verified? "yes":"no");
839 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_peerdn != NULL)
840 s = string_append(s, &size, &ptr, 3, US" DN=\"",
841 string_printing(tls_peerdn), US"\"");
844 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
845 US" C=..." : US" C=";
846 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
848 if (smtp_connection_had[i] != SCH_NONE)
850 s = string_append(s, &size, &ptr, 2, sep,
851 smtp_names[smtp_connection_had[i]]);
856 for (i = 0; i < smtp_ch_index; i++)
858 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
862 if (s != NULL) s[ptr] = 0; else s = US"";
863 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
864 host_and_ident(FALSE),
865 readconf_printtime(time(NULL) - smtp_connection_start), s);
870 /*************************************************
871 * Check HELO line and set sender_helo_name *
872 *************************************************/
874 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
875 the domain name of the sending host, or an ip literal in square brackets. The
876 arrgument is placed in sender_helo_name, which is in malloc store, because it
877 must persist over multiple incoming messages. If helo_accept_junk is set, this
878 host is permitted to send any old junk (needed for some broken hosts).
879 Otherwise, helo_allow_chars can be used for rogue characters in general
880 (typically people want to let in underscores).
883 s the data portion of the line (already past any white space)
885 Returns: TRUE or FALSE
889 check_helo(uschar *s)
892 uschar *end = s + Ustrlen(s);
893 BOOL yield = helo_accept_junk;
895 /* Discard any previous helo name */
897 if (sender_helo_name != NULL)
899 store_free(sender_helo_name);
900 sender_helo_name = NULL;
903 /* Skip tests if junk is permitted. */
907 /* Allow the new standard form for IPv6 address literals, namely,
908 [IPv6:....], and because someone is bound to use it, allow an equivalent
909 IPv4 form. Allow plain addresses as well. */
916 if (strncmpic(s, US"[IPv6:", 6) == 0)
917 yield = (string_is_ip_address(s+6, NULL) == 6);
918 else if (strncmpic(s, US"[IPv4:", 6) == 0)
919 yield = (string_is_ip_address(s+6, NULL) == 4);
921 yield = (string_is_ip_address(s+1, NULL) != 0);
926 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
927 that have been configured (usually underscore - sigh). */
934 if (!isalnum(*s) && *s != '.' && *s != '-' &&
935 Ustrchr(helo_allow_chars, *s) == NULL)
945 /* Save argument if OK */
947 if (yield) sender_helo_name = string_copy_malloc(start);
955 /*************************************************
956 * Extract SMTP command option *
957 *************************************************/
959 /* This function picks the next option setting off the end of smtp_cmd_data. It
960 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
961 things that can appear there.
964 name point this at the name
965 value point this at the data string
967 Returns: TRUE if found an option
971 extract_option(uschar **name, uschar **value)
974 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
975 while (isspace(*v)) v--;
978 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
979 if (*v != '=') return FALSE;
982 while(isalpha(n[-1])) n--;
984 if (n[-1] != ' ') return FALSE;
997 /*************************************************
998 * Reset for new message *
999 *************************************************/
1001 /* This function is called whenever the SMTP session is reset from
1002 within either of the setup functions.
1004 Argument: the stacking pool storage reset point
1009 smtp_reset(void *reset_point)
1011 store_reset(reset_point);
1012 recipients_list = NULL;
1013 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1014 raw_recipients_count = recipients_count = recipients_list_max = 0;
1015 message_linecount = 0;
1017 acl_added_headers = NULL;
1018 queue_only_policy = FALSE;
1019 rcpt_smtp_response = NULL;
1020 rcpt_smtp_response_same = TRUE;
1021 rcpt_in_progress = FALSE;
1022 deliver_freeze = FALSE; /* Can be set by ACL */
1023 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1024 fake_response = OK; /* Can be set by ACL */
1025 #ifdef WITH_CONTENT_SCAN
1026 no_mbox_unspool = FALSE; /* Can be set by ACL */
1028 submission_mode = FALSE; /* Can be set by ACL */
1029 suppress_local_fixups = FALSE; /* Can be set by ACL */
1030 active_local_from_check = local_from_check; /* Can be set by ACL */
1031 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1032 sender_address = NULL;
1033 submission_name = NULL; /* Can be set by ACL */
1034 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1035 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1036 sender_verified_list = NULL; /* No senders verified */
1037 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1038 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1039 authenticated_sender = NULL;
1040 #ifdef EXPERIMENTAL_BRIGHTMAIL
1042 bmi_verdicts = NULL;
1044 #ifndef DISABLE_DKIM
1045 dkim_signers = NULL;
1046 dkim_disable_verify = FALSE;
1047 dkim_collect_input = FALSE;
1049 #ifdef EXPERIMENTAL_SPF
1050 spf_header_comment = NULL;
1051 spf_received = NULL;
1053 spf_smtp_comment = NULL;
1055 body_linecount = body_zerocount = 0;
1057 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1058 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1059 /* Note that ratelimiters_conn persists across resets. */
1061 /* Reset message ACL variables */
1065 /* The message body variables use malloc store. They may be set if this is
1066 not the first message in an SMTP session and the previous message caused them
1067 to be referenced in an ACL. */
1069 if (message_body != NULL)
1071 store_free(message_body);
1072 message_body = NULL;
1075 if (message_body_end != NULL)
1077 store_free(message_body_end);
1078 message_body_end = NULL;
1081 /* Warning log messages are also saved in malloc store. They are saved to avoid
1082 repetition in the same message, but it seems right to repeat them for different
1085 while (acl_warn_logged != NULL)
1087 string_item *this = acl_warn_logged;
1088 acl_warn_logged = acl_warn_logged->next;
1097 /*************************************************
1098 * Initialize for incoming batched SMTP message *
1099 *************************************************/
1101 /* This function is called from smtp_setup_msg() in the case when
1102 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1103 of messages in one file with SMTP commands between them. All errors must be
1104 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1105 relevant. After an error on a sender, or an invalid recipient, the remainder
1106 of the message is skipped. The value of received_protocol is already set.
1109 Returns: > 0 message successfully started (reached DATA)
1110 = 0 QUIT read or end of file reached
1111 < 0 should not occur
1115 smtp_setup_batch_msg(void)
1118 void *reset_point = store_get(0);
1120 /* Save the line count at the start of each transaction - single commands
1121 like HELO and RSET count as whole transactions. */
1123 bsmtp_transaction_linecount = receive_linecount;
1125 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1127 smtp_reset(reset_point); /* Reset for start of message */
1129 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1130 value. The values are 2 larger than the required yield of the function. */
1135 uschar *recipient = NULL;
1136 int start, end, sender_domain, recipient_domain;
1138 switch(smtp_read_command(FALSE))
1140 /* The HELO/EHLO commands set sender_address_helo if they have
1141 valid data; otherwise they are ignored, except that they do
1142 a reset of the state. */
1147 check_helo(smtp_cmd_data);
1151 smtp_reset(reset_point);
1152 bsmtp_transaction_linecount = receive_linecount;
1156 /* The MAIL FROM command requires an address as an operand. All we
1157 do here is to parse it for syntactic correctness. The form "<>" is
1158 a special case which converts into an empty string. The start/end
1159 pointers in the original are not used further for this address, as
1160 it is the canonical extracted address which is all that is kept. */
1163 if (sender_address != NULL)
1164 /* The function moan_smtp_batch() does not return. */
1165 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1167 if (smtp_cmd_data[0] == 0)
1168 /* The function moan_smtp_batch() does not return. */
1169 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1171 /* Reset to start of message */
1173 smtp_reset(reset_point);
1175 /* Apply SMTP rewrite */
1177 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1178 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1179 US"", global_rewrite_rules) : smtp_cmd_data;
1181 /* Extract the address; the TRUE flag allows <> as valid */
1184 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1187 if (raw_sender == NULL)
1188 /* The function moan_smtp_batch() does not return. */
1189 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1191 sender_address = string_copy(raw_sender);
1193 /* Qualify unqualified sender addresses if permitted to do so. */
1195 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1197 if (allow_unqualified_sender)
1199 sender_address = rewrite_address_qualify(sender_address, FALSE);
1200 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1201 "and rewritten\n", raw_sender);
1203 /* The function moan_smtp_batch() does not return. */
1204 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1210 /* The RCPT TO command requires an address as an operand. All we do
1211 here is to parse it for syntactic correctness. There may be any number
1212 of RCPT TO commands, specifying multiple senders. We build them all into
1213 a data structure that is in argc/argv format. The start/end values
1214 given by parse_extract_address are not used, as we keep only the
1215 extracted address. */
1218 if (sender_address == NULL)
1219 /* The function moan_smtp_batch() does not return. */
1220 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1222 if (smtp_cmd_data[0] == 0)
1223 /* The function moan_smtp_batch() does not return. */
1224 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1226 /* Check maximum number allowed */
1228 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1229 /* The function moan_smtp_batch() does not return. */
1230 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1231 recipients_max_reject? "552": "452");
1233 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1234 recipient address */
1236 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1237 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1238 global_rewrite_rules) : smtp_cmd_data;
1240 /* rfc821_domains = TRUE; << no longer needed */
1241 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1242 &recipient_domain, FALSE);
1243 /* rfc821_domains = FALSE; << no longer needed */
1245 if (recipient == NULL)
1246 /* The function moan_smtp_batch() does not return. */
1247 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1249 /* If the recipient address is unqualified, qualify it if permitted. Then
1250 add it to the list of recipients. */
1252 if (recipient_domain == 0)
1254 if (allow_unqualified_recipient)
1256 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1258 recipient = rewrite_address_qualify(recipient, TRUE);
1260 /* The function moan_smtp_batch() does not return. */
1261 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1264 receive_add_recipient(recipient, -1);
1268 /* The DATA command is legal only if it follows successful MAIL FROM
1269 and RCPT TO commands. This function is complete when a valid DATA
1270 command is encountered. */
1273 if (sender_address == NULL || recipients_count <= 0)
1275 /* The function moan_smtp_batch() does not return. */
1276 if (sender_address == NULL)
1277 moan_smtp_batch(smtp_cmd_buffer,
1278 "503 MAIL FROM:<sender> command must precede DATA");
1280 moan_smtp_batch(smtp_cmd_buffer,
1281 "503 RCPT TO:<recipient> must precede DATA");
1285 done = 3; /* DATA successfully achieved */
1286 message_ended = END_NOTENDED; /* Indicate in middle of message */
1291 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1298 bsmtp_transaction_linecount = receive_linecount;
1309 /* The function moan_smtp_batch() does not return. */
1310 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1315 /* The function moan_smtp_batch() does not return. */
1316 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1321 /* The function moan_smtp_batch() does not return. */
1322 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1327 return done - 2; /* Convert yield values */
1333 /*************************************************
1334 * Start an SMTP session *
1335 *************************************************/
1337 /* This function is called at the start of an SMTP session. Thereafter,
1338 smtp_setup_msg() is called to initiate each separate message. This
1339 function does host-specific testing, and outputs the banner line.
1342 Returns: FALSE if the session can not continue; something has
1343 gone wrong, or the connection to the host is blocked
1347 smtp_start_session(void)
1351 uschar *user_msg, *log_msg;
1355 smtp_connection_start = time(NULL);
1356 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1357 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1360 /* Default values for certain variables */
1362 helo_seen = esmtp = helo_accept_junk = FALSE;
1363 smtp_mailcmd_count = 0;
1364 count_nonmail = TRUE_UNSET;
1365 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1366 smtp_delay_mail = smtp_rlm_base;
1367 auth_advertised = FALSE;
1368 pipelining_advertised = FALSE;
1369 pipelining_enable = TRUE;
1370 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1371 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1373 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1375 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1376 authentication settings from -oMaa to remain in force. */
1378 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1379 authenticated_by = NULL;
1382 tls_cipher = tls_peerdn = NULL;
1383 tls_advertised = FALSE;
1386 /* Reset ACL connection variables */
1390 /* Allow for trailing 0 in the command and data buffers. */
1392 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1393 if (smtp_cmd_buffer == NULL)
1394 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1395 "malloc() failed for SMTP command buffer");
1396 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1398 /* For batched input, the protocol setting can be overridden from the
1399 command line by a trusted caller. */
1401 if (smtp_batched_input)
1403 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1406 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1407 reset later if any of EHLO/AUTH/STARTTLS are received. */
1411 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1413 /* Set up the buffer for inputting using direct read() calls, and arrange to
1414 call the local functions instead of the standard C ones. */
1416 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1417 if (smtp_inbuffer == NULL)
1418 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1419 receive_getc = smtp_getc;
1420 receive_ungetc = smtp_ungetc;
1421 receive_feof = smtp_feof;
1422 receive_ferror = smtp_ferror;
1423 receive_smtp_buffered = smtp_buffered;
1424 smtp_inptr = smtp_inend = smtp_inbuffer;
1425 smtp_had_eof = smtp_had_error = 0;
1427 /* Set up the message size limit; this may be host-specific */
1429 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1430 if (expand_string_message != NULL)
1432 if (thismessage_size_limit == -1)
1433 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1434 "%s", expand_string_message);
1436 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1437 "%s", expand_string_message);
1438 smtp_closedown(US"Temporary local problem - please try later");
1442 /* When a message is input locally via the -bs or -bS options, sender_host_
1443 unknown is set unless -oMa was used to force an IP address, in which case it
1444 is checked like a real remote connection. When -bs is used from inetd, this
1445 flag is not set, causing the sending host to be checked. The code that deals
1446 with IP source routing (if configured) is never required for -bs or -bS and
1447 the flag sender_host_notsocket is used to suppress it.
1449 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1450 reserve for certain hosts and/or networks. */
1452 if (!sender_host_unknown)
1455 BOOL reserved_host = FALSE;
1457 /* Look up IP options (source routing info) on the socket if this is not an
1458 -oMa "host", and if any are found, log them and drop the connection.
1460 Linux (and others now, see below) is different to everyone else, so there
1461 has to be some conditional compilation here. Versions of Linux before 2.1.15
1462 used a structure whose name was "options". Somebody finally realized that
1463 this name was silly, and it got changed to "ip_options". I use the
1464 newer name here, but there is a fudge in the script that sets up os.h
1465 to define a macro in older Linux systems.
1467 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1468 glibc 2, which has chosen ip_opts for the structure name. This is now
1469 really a glibc thing rather than a Linux thing, so the condition name
1470 has been changed to reflect this. It is relevant also to GNU/Hurd.
1472 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1473 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1474 a special macro defined in the os.h file.
1476 Some DGUX versions on older hardware appear not to support IP options at
1477 all, so there is now a general macro which can be set to cut out this
1480 How to do this properly in IPv6 is not yet known. */
1482 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1484 #ifdef GLIBC_IP_OPTIONS
1485 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1490 #elif defined DARWIN_IP_OPTIONS
1496 if (!host_checking && !sender_host_notsocket)
1499 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1500 struct ip_options *ipopt = store_get(optlen);
1502 struct ip_opts ipoptblock;
1503 struct ip_opts *ipopt = &ipoptblock;
1504 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1506 struct ipoption ipoptblock;
1507 struct ipoption *ipopt = &ipoptblock;
1508 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1511 /* Occasional genuine failures of getsockopt() have been seen - for
1512 example, "reset by peer". Therefore, just log and give up on this
1513 call, unless the error is ENOPROTOOPT. This error is given by systems
1514 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1515 of writing. So for that error, carry on - we just can't do an IP options
1518 DEBUG(D_receive) debug_printf("checking for IP options\n");
1520 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1523 if (errno != ENOPROTOOPT)
1525 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1526 host_and_ident(FALSE), strerror(errno));
1527 smtp_printf("451 SMTP service not available\r\n");
1532 /* Deal with any IP options that are set. On the systems I have looked at,
1533 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1534 more logging data than will fit in big_buffer. Nevertheless, after somebody
1535 questioned this code, I've added in some paranoid checking. */
1537 else if (optlen > 0)
1539 uschar *p = big_buffer;
1540 uschar *pend = big_buffer + big_buffer_size;
1541 uschar *opt, *adptr;
1543 struct in_addr addr;
1546 uschar *optstart = (uschar *)(ipopt->__data);
1548 uschar *optstart = (uschar *)(ipopt->ip_opts);
1550 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1553 DEBUG(D_receive) debug_printf("IP options exist\n");
1555 Ustrcpy(p, "IP options on incoming call:");
1558 for (opt = optstart; opt != NULL &&
1559 opt < (uschar *)(ipopt) + optlen;)
1573 if (!string_format(p, pend-p, " %s [@%s",
1574 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1576 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1578 inet_ntoa(ipopt->ip_dst)))
1580 inet_ntoa(ipopt->ipopt_dst)))
1588 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1590 while (optcount-- > 0)
1592 memcpy(&addr, adptr, sizeof(addr));
1593 if (!string_format(p, pend - p - 1, "%s%s",
1594 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1600 adptr += sizeof(struct in_addr);
1609 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1612 for (i = 0; i < opt[1]; i++)
1614 sprintf(CS p, "%2.2x ", opt[i]);
1625 log_write(0, LOG_MAIN, "%s", big_buffer);
1627 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1629 log_write(0, LOG_MAIN|LOG_REJECT,
1630 "connection from %s refused (IP options)", host_and_ident(FALSE));
1632 smtp_printf("554 SMTP service not available\r\n");
1636 /* Length of options = 0 => there are no options */
1638 else DEBUG(D_receive) debug_printf("no IP options found\n");
1640 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1642 /* Set keep-alive in socket options. The option is on by default. This
1643 setting is an attempt to get rid of some hanging connections that stick in
1644 read() when the remote end (usually a dialup) goes away. */
1646 if (smtp_accept_keepalive && !sender_host_notsocket)
1647 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1649 /* If the current host matches host_lookup, set the name by doing a
1650 reverse lookup. On failure, sender_host_name will be NULL and
1651 host_lookup_failed will be TRUE. This may or may not be serious - optional
1654 if (verify_check_host(&host_lookup) == OK)
1656 (void)host_name_lookup();
1657 host_build_sender_fullhost();
1660 /* Delay this until we have the full name, if it is looked up. */
1662 set_process_info("handling incoming connection from %s",
1663 host_and_ident(FALSE));
1665 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1666 smtps port for use with older style SSL MTAs. */
1669 if (tls_on_connect &&
1670 tls_server_start(tls_require_ciphers,
1671 gnutls_require_mac, gnutls_require_kx, gnutls_require_proto) != OK)
1675 /* Test for explicit connection rejection */
1677 if (verify_check_host(&host_reject_connection) == OK)
1679 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1680 "from %s (host_reject_connection)", host_and_ident(FALSE));
1681 smtp_printf("554 SMTP service not available\r\n");
1685 /* Test with TCP Wrappers if so configured. There is a problem in that
1686 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1687 such as disks dying. In these cases, it is desirable to reject with a 4xx
1688 error instead of a 5xx error. There isn't a "right" way to detect such
1689 problems. The following kludge is used: errno is zeroed before calling
1690 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1691 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1694 #ifdef USE_TCP_WRAPPERS
1696 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
1697 if (tcp_wrappers_name == NULL)
1699 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
1700 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
1701 expand_string_message);
1703 if (!hosts_ctl(tcp_wrappers_name,
1704 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1705 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1706 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1708 if (errno == 0 || errno == ENOENT)
1710 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1711 log_write(L_connection_reject,
1712 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1713 "(tcp wrappers)", host_and_ident(FALSE));
1714 smtp_printf("554 SMTP service not available\r\n");
1718 int save_errno = errno;
1719 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1720 "errno value %d\n", save_errno);
1721 log_write(L_connection_reject,
1722 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1723 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1724 smtp_printf("451 Temporary local problem - please try later\r\n");
1730 /* Check for reserved slots. The value of smtp_accept_count has already been
1731 incremented to include this process. */
1733 if (smtp_accept_max > 0 &&
1734 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
1736 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1738 log_write(L_connection_reject,
1739 LOG_MAIN, "temporarily refused connection from %s: not in "
1740 "reserve list: connected=%d max=%d reserve=%d%s",
1741 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
1742 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1743 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1744 "please try again later\r\n", smtp_active_hostname);
1747 reserved_host = TRUE;
1750 /* If a load level above which only messages from reserved hosts are
1751 accepted is set, check the load. For incoming calls via the daemon, the
1752 check is done in the superior process if there are no reserved hosts, to
1753 save a fork. In all cases, the load average will already be available
1754 in a global variable at this point. */
1756 if (smtp_load_reserve >= 0 &&
1757 load_average > smtp_load_reserve &&
1759 verify_check_host(&smtp_reserve_hosts) != OK)
1761 log_write(L_connection_reject,
1762 LOG_MAIN, "temporarily refused connection from %s: not in "
1763 "reserve list and load average = %.2f", host_and_ident(FALSE),
1764 (double)load_average/1000.0);
1765 smtp_printf("421 %s: Too much load; please try again later\r\n",
1766 smtp_active_hostname);
1770 /* Determine whether unqualified senders or recipients are permitted
1771 for this host. Unfortunately, we have to do this every time, in order to
1772 set the flags so that they can be inspected when considering qualifying
1773 addresses in the headers. For a site that permits no qualification, this
1774 won't take long, however. */
1776 allow_unqualified_sender =
1777 verify_check_host(&sender_unqualified_hosts) == OK;
1779 allow_unqualified_recipient =
1780 verify_check_host(&recipient_unqualified_hosts) == OK;
1782 /* Determine whether HELO/EHLO is required for this host. The requirement
1783 can be hard or soft. */
1785 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1787 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1789 /* Determine whether this hosts is permitted to send syntactic junk
1790 after a HELO or EHLO command. */
1792 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1795 /* For batch SMTP input we are now done. */
1797 if (smtp_batched_input) return TRUE;
1799 /* Run the ACL if it exists */
1802 if (acl_smtp_connect != NULL)
1805 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1809 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1814 /* Output the initial message for a two-way SMTP connection. It may contain
1815 newlines, which then cause a multi-line response to be given. */
1817 code = US"220"; /* Default status code */
1818 esc = US""; /* Default extended status code */
1819 esclen = 0; /* Length of esc */
1821 if (user_msg == NULL)
1823 s = expand_string(smtp_banner);
1825 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1826 "failed: %s", smtp_banner, expand_string_message);
1832 smtp_message_code(&code, &codelen, &s, NULL);
1836 esclen = codelen - 4;
1840 /* Remove any terminating newlines; might as well remove trailing space too */
1843 while (p > s && isspace(p[-1])) p--;
1846 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1847 is all contained in a single IP packet. The original code wrote out the
1848 greeting using several calls to fprint/fputc, and on busy servers this could
1849 cause it to be split over more than one packet - which caused CC:Mail to fall
1850 over when it got the second part of the greeting after sending its first
1851 command. Sigh. To try to avoid this, build the complete greeting message
1852 first, and output it in one fell swoop. This gives a better chance of it
1853 ending up as a single packet. */
1855 ss = store_get(size);
1859 do /* At least once, in case we have an empty string */
1862 uschar *linebreak = Ustrchr(p, '\n');
1863 ss = string_cat(ss, &size, &ptr, code, 3);
1864 if (linebreak == NULL)
1867 ss = string_cat(ss, &size, &ptr, US" ", 1);
1871 len = linebreak - p;
1872 ss = string_cat(ss, &size, &ptr, US"-", 1);
1874 ss = string_cat(ss, &size, &ptr, esc, esclen);
1875 ss = string_cat(ss, &size, &ptr, p, len);
1876 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1878 if (linebreak != NULL) p++;
1882 ss[ptr] = 0; /* string_cat leaves room for this */
1884 /* Before we write the banner, check that there is no input pending, unless
1885 this synchronisation check is disabled. */
1889 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1890 "synchronization error (input sent without waiting for greeting): "
1891 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1892 string_printing(smtp_inptr));
1893 smtp_printf("554 SMTP synchronization error\r\n");
1897 /* Now output the banner */
1899 smtp_printf("%s", ss);
1907 /*************************************************
1908 * Handle SMTP syntax and protocol errors *
1909 *************************************************/
1911 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1912 to do so. Then transmit the error response. The return value depends on the
1913 number of syntax and protocol errors in this SMTP session.
1916 type error type, given as a log flag bit
1917 code response code; <= 0 means don't send a response
1918 data data to reflect in the response (can be NULL)
1919 errmess the error message
1921 Returns: -1 limit of syntax/protocol errors NOT exceeded
1922 +1 limit of syntax/protocol errors IS exceeded
1924 These values fit in with the values of the "done" variable in the main
1925 processing loop in smtp_setup_msg(). */
1928 synprot_error(int type, int code, uschar *data, uschar *errmess)
1932 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1933 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1934 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1936 if (++synprot_error_count > smtp_max_synprot_errors)
1939 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1940 "syntax or protocol errors (last command was \"%s\")",
1941 host_and_ident(FALSE), smtp_cmd_buffer);
1946 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1947 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1949 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1958 /*************************************************
1959 * Log incomplete transactions *
1960 *************************************************/
1962 /* This function is called after a transaction has been aborted by RSET, QUIT,
1963 connection drops or other errors. It logs the envelope information received
1964 so far in order to preserve address verification attempts.
1966 Argument: string to indicate what aborted the transaction
1971 incomplete_transaction_log(uschar *what)
1973 if (sender_address == NULL || /* No transaction in progress */
1974 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1977 /* Build list of recipients for logging */
1979 if (recipients_count > 0)
1982 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1983 for (i = 0; i < recipients_count; i++)
1984 raw_recipients[i] = recipients_list[i].address;
1985 raw_recipients_count = recipients_count;
1988 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1989 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1995 /*************************************************
1996 * Send SMTP response, possibly multiline *
1997 *************************************************/
1999 /* There are, it seems, broken clients out there that cannot handle multiline
2000 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2001 output nothing for non-final calls, and only the first line for anything else.
2004 code SMTP code, may involve extended status codes
2005 codelen length of smtp code; if > 4 there's an ESC
2006 final FALSE if the last line isn't the final line
2007 msg message text, possibly containing newlines
2013 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2018 if (!final && no_multiline_responses) return;
2023 esclen = codelen - 4;
2026 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2027 have had the same. Note: this code is also present in smtp_printf(). It would
2028 be tidier to have it only in one place, but when it was added, it was easier to
2029 do it that way, so as not to have to mess with the code for the RCPT command,
2030 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2032 if (rcpt_in_progress)
2034 if (rcpt_smtp_response == NULL)
2035 rcpt_smtp_response = string_copy(msg);
2036 else if (rcpt_smtp_response_same &&
2037 Ustrcmp(rcpt_smtp_response, msg) != 0)
2038 rcpt_smtp_response_same = FALSE;
2039 rcpt_in_progress = FALSE;
2042 /* Not output the message, splitting it up into multiple lines if necessary. */
2046 uschar *nl = Ustrchr(msg, '\n');
2049 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2052 else if (nl[1] == 0 || no_multiline_responses)
2054 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2055 (int)(nl - msg), msg);
2060 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2062 while (isspace(*msg)) msg++;
2070 /*************************************************
2071 * Parse user SMTP message *
2072 *************************************************/
2074 /* This function allows for user messages overriding the response code details
2075 by providing a suitable response code string at the start of the message
2076 user_msg. Check the message for starting with a response code and optionally an
2077 extended status code. If found, check that the first digit is valid, and if so,
2078 change the code pointer and length to use the replacement. An invalid code
2079 causes a panic log; in this case, if the log messages is the same as the user
2080 message, we must also adjust the value of the log message to show the code that
2081 is actually going to be used (the original one).
2083 This function is global because it is called from receive.c as well as within
2086 Note that the code length returned includes the terminating whitespace
2087 character, which is always included in the regex match.
2090 code SMTP code, may involve extended status codes
2091 codelen length of smtp code; if > 4 there's an ESC
2093 log_msg optional log message, to be adjusted with the new SMTP code
2099 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2104 if (msg == NULL || *msg == NULL) return;
2106 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2107 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2110 if ((*msg)[0] != (*code)[0])
2112 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2113 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2114 if (log_msg != NULL && *log_msg == *msg)
2115 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2120 *codelen = ovector[1]; /* Includes final space */
2122 *msg += ovector[1]; /* Chop the code off the message */
2129 /*************************************************
2130 * Handle an ACL failure *
2131 *************************************************/
2133 /* This function is called when acl_check() fails. As well as calls from within
2134 this module, it is called from receive.c for an ACL after DATA. It sorts out
2135 logging the incident, and sets up the error response. A message containing
2136 newlines is turned into a multiline SMTP response, but for logging, only the
2139 There's a table of default permanent failure response codes to use in
2140 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2141 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2142 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2143 state, because there are broken clients that try VRFY before RCPT. A 5xx
2144 response should be given only when the address is positively known to be
2145 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2148 From Exim 4.63, it is possible to override the response code details by
2149 providing a suitable response code string at the start of the message provided
2150 in user_msg. The code's first digit is checked for validity.
2153 where where the ACL was called from
2155 user_msg a message that can be included in an SMTP response
2156 log_msg a message for logging
2158 Returns: 0 in most cases
2159 2 if the failure code was FAIL_DROP, in which case the
2160 SMTP connection should be dropped (this value fits with the
2161 "done" variable in smtp_setup_msg() below)
2165 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2167 BOOL drop = rc == FAIL_DROP;
2171 uschar *sender_info = US"";
2173 #ifdef WITH_CONTENT_SCAN
2174 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2176 (where == ACL_WHERE_PREDATA)? US"DATA" :
2177 (where == ACL_WHERE_DATA)? US"after DATA" :
2178 (smtp_cmd_data == NULL)?
2179 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2180 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2182 if (drop) rc = FAIL;
2184 /* Set the default SMTP code, and allow a user message to change it. */
2186 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2187 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2189 /* We used to have sender_address here; however, there was a bug that was not
2190 updating sender_address after a rewrite during a verify. When this bug was
2191 fixed, sender_address at this point became the rewritten address. I'm not sure
2192 this is what should be logged, so I've changed to logging the unrewritten
2193 address to retain backward compatibility. */
2195 #ifndef WITH_CONTENT_SCAN
2196 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2198 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2201 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
2202 sender_address_unrewritten : sender_address);
2205 /* If there's been a sender verification failure with a specific message, and
2206 we have not sent a response about it yet, do so now, as a preliminary line for
2207 failures, but not defers. However, always log it for defer, and log it for fail
2208 unless the sender_verify_fail log selector has been turned off. */
2210 if (sender_verified_failed != NULL &&
2211 !testflag(sender_verified_failed, af_sverify_told))
2213 BOOL save_rcpt_in_progress = rcpt_in_progress;
2214 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2216 setflag(sender_verified_failed, af_sverify_told);
2218 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2219 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2220 host_and_ident(TRUE),
2221 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2222 sender_verified_failed->address,
2223 (sender_verified_failed->message == NULL)? US"" :
2224 string_sprintf(": %s", sender_verified_failed->message));
2226 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2227 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2228 testflag(sender_verified_failed, af_verify_pmfail)?
2229 "Postmaster verification failed while checking <%s>\n%s\n"
2230 "Several RFCs state that you are required to have a postmaster\n"
2231 "mailbox for each mail domain. This host does not accept mail\n"
2232 "from domains whose servers reject the postmaster address."
2234 testflag(sender_verified_failed, af_verify_nsfail)?
2235 "Callback setup failed while verifying <%s>\n%s\n"
2236 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2237 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2238 "RFC requirements, and stops you from receiving standard bounce\n"
2239 "messages. This host does not accept mail from domains whose servers\n"
2242 "Verification failed for <%s>\n%s",
2243 sender_verified_failed->address,
2244 sender_verified_failed->user_message));
2246 rcpt_in_progress = save_rcpt_in_progress;
2249 /* Sort out text for logging */
2251 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2252 lognl = Ustrchr(log_msg, '\n');
2253 if (lognl != NULL) *lognl = 0;
2255 /* Send permanent failure response to the command, but the code used isn't
2256 always a 5xx one - see comments at the start of this function. If the original
2257 rc was FAIL_DROP we drop the connection and yield 2. */
2259 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2260 US"Administrative prohibition" : user_msg);
2262 /* Send temporary failure response to the command. Don't give any details,
2263 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2264 verb, and for a header verify when smtp_return_error_details is set.
2266 This conditional logic is all somewhat of a mess because of the odd
2267 interactions between temp_details and return_error_details. One day it should
2268 be re-implemented in a tidier fashion. */
2272 if (acl_temp_details && user_msg != NULL)
2274 if (smtp_return_error_details &&
2275 sender_verified_failed != NULL &&
2276 sender_verified_failed->message != NULL)
2278 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2280 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2283 smtp_respond(smtp_code, codelen, TRUE,
2284 US"Temporary local problem - please try later");
2287 /* Log the incident to the logs that are specified by log_reject_target
2288 (default main, reject). This can be empty to suppress logging of rejections. If
2289 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2290 is closing if required and return 2. */
2292 if (log_reject_target != 0)
2293 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2294 host_and_ident(TRUE),
2295 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2297 if (!drop) return 0;
2299 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2300 smtp_get_connection_info());
2302 /* Run the not-quit ACL, but without any custom messages. This should not be a
2303 problem, because we get here only if some other ACL has issued "drop", and
2304 in that case, *its* custom messages will have been used above. */
2306 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2313 /*************************************************
2314 * Handle SMTP exit when QUIT is not given *
2315 *************************************************/
2317 /* This function provides a logging/statistics hook for when an SMTP connection
2318 is dropped on the floor or the other end goes away. It's a global function
2319 because it's called from receive.c as well as this module. As well as running
2320 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2321 response, either with a custom message from the ACL, or using a default. There
2322 is one case, however, when no message is output - after "drop". In that case,
2323 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2324 passed to this function.
2326 In case things go wrong while processing this function, causing an error that
2327 may re-enter this funtion, there is a recursion check.
2330 reason What $smtp_notquit_reason will be set to in the ACL;
2331 if NULL, the ACL is not run
2332 code The error code to return as part of the response
2333 defaultrespond The default message if there's no user_msg
2339 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2342 uschar *user_msg = NULL;
2343 uschar *log_msg = NULL;
2345 /* Check for recursive acll */
2347 if (smtp_exit_function_called)
2349 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2353 smtp_exit_function_called = TRUE;
2355 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2357 if (acl_smtp_notquit != NULL && reason != NULL)
2359 smtp_notquit_reason = reason;
2360 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2363 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2367 /* Write an SMTP response if we are expected to give one. As the default
2368 responses are all internal, they should always fit in the buffer, but code a
2369 warning, just in case. Note that string_vformat() still leaves a complete
2370 string, even if it is incomplete. */
2372 if (code != NULL && defaultrespond != NULL)
2374 if (user_msg == NULL)
2378 va_start(ap, defaultrespond);
2379 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2380 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2381 smtp_printf("%s %s\r\n", code, buffer);
2385 smtp_respond(code, 3, TRUE, user_msg);
2393 /*************************************************
2394 * Verify HELO argument *
2395 *************************************************/
2397 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2398 matched. It is also called from ACL processing if verify = helo is used and
2399 verification was not previously tried (i.e. helo_try_verify_hosts was not
2400 matched). The result of its processing is to set helo_verified and
2401 helo_verify_failed. These variables should both be FALSE for this function to
2404 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2405 for IPv6 ::ffff: literals.
2408 Returns: TRUE if testing was completed;
2409 FALSE on a temporary failure
2413 smtp_verify_helo(void)
2417 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2420 if (sender_helo_name == NULL)
2422 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2425 /* Deal with the case of -bs without an IP address */
2427 else if (sender_host_address == NULL)
2429 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2430 helo_verified = TRUE;
2433 /* Deal with the more common case when there is a sending IP address */
2435 else if (sender_helo_name[0] == '[')
2437 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2438 Ustrlen(sender_host_address)) == 0;
2443 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2444 helo_verified = Ustrncmp(sender_helo_name + 1,
2445 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2450 { if (helo_verified) debug_printf("matched host address\n"); }
2453 /* Do a reverse lookup if one hasn't already given a positive or negative
2454 response. If that fails, or the name doesn't match, try checking with a forward
2459 if (sender_host_name == NULL && !host_lookup_failed)
2460 yield = host_name_lookup() != DEFER;
2462 /* If a host name is known, check it and all its aliases. */
2464 if (sender_host_name != NULL)
2466 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2470 HDEBUG(D_receive) debug_printf("matched host name\n");
2474 uschar **aliases = sender_host_aliases;
2475 while (*aliases != NULL)
2477 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2478 if (helo_verified) break;
2483 debug_printf("matched alias %s\n", *(--aliases));
2488 /* Final attempt: try a forward lookup of the helo name */
2494 h.name = sender_helo_name;
2498 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2500 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2501 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2506 if (Ustrcmp(hh->address, sender_host_address) == 0)
2508 helo_verified = TRUE;
2510 debug_printf("IP address for %s matches calling address\n",
2520 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2527 /*************************************************
2528 * Send user response message *
2529 *************************************************/
2531 /* This function is passed a default response code and a user message. It calls
2532 smtp_message_code() to check and possibly modify the response code, and then
2533 calls smtp_respond() to transmit the response. I put this into a function
2534 just to avoid a lot of repetition.
2537 code the response code
2538 user_msg the user message
2544 smtp_user_msg(uschar *code, uschar *user_msg)
2547 smtp_message_code(&code, &len, &user_msg, NULL);
2548 smtp_respond(code, len, TRUE, user_msg);
2554 /*************************************************
2555 * Initialize for SMTP incoming message *
2556 *************************************************/
2558 /* This function conducts the initial dialogue at the start of an incoming SMTP
2559 message, and builds a list of recipients. However, if the incoming message
2560 is part of a batch (-bS option) a separate function is called since it would
2561 be messy having tests splattered about all over this function. This function
2562 therefore handles the case where interaction is occurring. The input and output
2563 files are set up in smtp_in and smtp_out.
2565 The global recipients_list is set to point to a vector of recipient_item
2566 blocks, whose number is given by recipients_count. This is extended by the
2567 receive_add_recipient() function. The global variable sender_address is set to
2568 the sender's address. The yield is +1 if a message has been successfully
2569 started, 0 if a QUIT command was encountered or the connection was refused from
2570 the particular host, or -1 if the connection was lost.
2574 Returns: > 0 message successfully started (reached DATA)
2575 = 0 QUIT read or end of file reached or call refused
2580 smtp_setup_msg(void)
2583 BOOL toomany = FALSE;
2584 BOOL discarded = FALSE;
2585 BOOL last_was_rej_mail = FALSE;
2586 BOOL last_was_rcpt = FALSE;
2587 void *reset_point = store_get(0);
2589 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2591 /* Reset for start of new message. We allow one RSET not to be counted as a
2592 nonmail command, for those MTAs that insist on sending it between every
2593 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2594 TLS between messages (an Exim client may do this if it has messages queued up
2595 for the host). Note: we do NOT reset AUTH at this point. */
2597 smtp_reset(reset_point);
2598 message_ended = END_NOTSTARTED;
2600 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2601 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2602 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2604 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2607 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2609 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2611 /* Batched SMTP is handled in a different function. */
2613 if (smtp_batched_input) return smtp_setup_batch_msg();
2615 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2616 value. The values are 2 larger than the required yield of the function. */
2621 uschar *etrn_command;
2622 uschar *etrn_serialize_key;
2624 uschar *log_msg, *smtp_code;
2625 uschar *user_msg = NULL;
2626 uschar *recipient = NULL;
2627 uschar *hello = NULL;
2628 uschar *set_id = NULL;
2630 BOOL was_rej_mail = FALSE;
2631 BOOL was_rcpt = FALSE;
2632 void (*oldsignal)(int);
2634 int start, end, sender_domain, recipient_domain;
2639 switch(smtp_read_command(TRUE))
2641 /* The AUTH command is not permitted to occur inside a transaction, and may
2642 occur successfully only once per connection. Actually, that isn't quite
2643 true. When TLS is started, all previous information about a connection must
2644 be discarded, so a new AUTH is permitted at that time.
2646 AUTH may only be used when it has been advertised. However, it seems that
2647 there are clients that send AUTH when it hasn't been advertised, some of
2648 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2649 So there's a get-out that allows this to happen.
2651 AUTH is initially labelled as a "nonmail command" so that one occurrence
2652 doesn't get counted. We change the label here so that multiple failing
2653 AUTHS will eventually hit the nonmail threshold. */
2657 authentication_failed = TRUE;
2658 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2660 if (!auth_advertised && !allow_auth_unadvertised)
2662 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2663 US"AUTH command used when not advertised");
2666 if (sender_host_authenticated != NULL)
2668 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2669 US"already authenticated");
2672 if (sender_address != NULL)
2674 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2675 US"not permitted in mail transaction");
2681 if (acl_smtp_auth != NULL)
2683 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2686 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2691 /* Find the name of the requested authentication mechanism. */
2694 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
2696 if (!isalnum(c) && c != '-' && c != '_')
2698 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2699 US"invalid character in authentication mechanism name");
2705 /* If not at the end of the line, we must be at white space. Terminate the
2706 name and move the pointer on to any data that may be present. */
2708 if (*smtp_cmd_data != 0)
2710 *smtp_cmd_data++ = 0;
2711 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
2714 /* Search for an authentication mechanism which is configured for use
2715 as a server and which has been advertised (unless, sigh, allow_auth_
2716 unadvertised is set). */
2718 for (au = auths; au != NULL; au = au->next)
2720 if (strcmpic(s, au->public_name) == 0 && au->server &&
2721 (au->advertised || allow_auth_unadvertised)) break;
2726 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2727 string_sprintf("%s authentication mechanism not supported", s));
2731 /* Run the checking code, passing the remainder of the command line as
2732 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2733 it as the only set numerical variable. The authenticator may set $auth<n>
2734 and also set other numeric variables. The $auth<n> variables are preferred
2735 nowadays; the numerical variables remain for backwards compatibility.
2737 Afterwards, have a go at expanding the set_id string, even if
2738 authentication failed - for bad passwords it can be useful to log the
2739 userid. On success, require set_id to expand and exist, and put it in
2740 authenticated_id. Save this in permanent store, as the working store gets
2741 reset at HELO, RSET, etc. */
2743 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2745 expand_nlength[0] = 0; /* $0 contains nothing */
2747 c = (au->info->servercode)(au, smtp_cmd_data);
2748 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2749 expand_nmax = -1; /* Reset numeric variables */
2750 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2752 /* The value of authenticated_id is stored in the spool file and printed in
2753 log lines. It must not contain binary zeros or newline characters. In
2754 normal use, it never will, but when playing around or testing, this error
2755 can (did) happen. To guard against this, ensure that the id contains only
2756 printing characters. */
2758 if (set_id != NULL) set_id = string_printing(set_id);
2760 /* For the non-OK cases, set up additional logging data if set_id
2765 if (set_id != NULL && *set_id != 0)
2766 set_id = string_sprintf(" (set_id=%s)", set_id);
2770 /* Switch on the result */
2775 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2777 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2778 sender_host_authenticated = au->name;
2779 authentication_failed = FALSE;
2781 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2782 ((sender_host_address != NULL)? pnlocal : 0);
2783 s = ss = US"235 Authentication succeeded";
2784 authenticated_by = au;
2788 /* Authentication succeeded, but we failed to expand the set_id string.
2789 Treat this as a temporary error. */
2791 auth_defer_msg = expand_string_message;
2795 s = string_sprintf("435 Unable to authenticate at present%s",
2796 auth_defer_user_msg);
2797 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2798 set_id, auth_defer_msg);
2802 s = ss = US"501 Invalid base64 data";
2806 s = ss = US"501 Authentication cancelled";
2810 s = ss = US"553 Initial data not expected";
2814 s = US"535 Incorrect authentication data";
2815 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2819 s = US"435 Internal error";
2820 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2821 "check", set_id, c);
2825 smtp_printf("%s\r\n", s);
2827 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2828 au->name, host_and_ident(FALSE), ss);
2830 break; /* AUTH_CMD */
2832 /* The HELO/EHLO commands are permitted to appear in the middle of a
2833 session as well as at the beginning. They have the effect of a reset in
2834 addition to their other functions. Their absence at the start cannot be
2835 taken to be an error.
2839 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2840 or 502 failure replies MUST be returned as appropriate. The SMTP
2841 server MUST stay in the same state after transmitting these replies
2842 that it was in before the EHLO was received.
2844 Therefore, we do not do the reset until after checking the command for
2845 acceptability. This change was made for Exim release 4.11. Previously
2846 it did the reset first. */
2859 HELO_EHLO: /* Common code for HELO and EHLO */
2860 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2861 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2863 /* Reject the HELO if its argument was invalid or non-existent. A
2864 successful check causes the argument to be saved in malloc store. */
2866 if (!check_helo(smtp_cmd_data))
2868 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2870 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2871 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2872 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2873 string_printing(smtp_cmd_argument));
2875 if (++synprot_error_count > smtp_max_synprot_errors)
2877 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2878 "syntax or protocol errors (last command was \"%s\")",
2879 host_and_ident(FALSE), smtp_cmd_buffer);
2886 /* If sender_host_unknown is true, we have got here via the -bs interface,
2887 not called from inetd. Otherwise, we are running an IP connection and the
2888 host address will be set. If the helo name is the primary name of this
2889 host and we haven't done a reverse lookup, force one now. If helo_required
2890 is set, ensure that the HELO name matches the actual host. If helo_verify
2891 is set, do the same check, but softly. */
2893 if (!sender_host_unknown)
2895 BOOL old_helo_verified = helo_verified;
2896 uschar *p = smtp_cmd_data;
2898 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2901 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2902 because otherwise the log can be confusing. */
2904 if (sender_host_name == NULL &&
2905 (deliver_domain = sender_helo_name, /* set $domain */
2906 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2907 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2908 (void)host_name_lookup();
2910 /* Rebuild the fullhost info to include the HELO name (and the real name
2911 if it was looked up.) */
2913 host_build_sender_fullhost(); /* Rebuild */
2914 set_process_info("handling%s incoming connection from %s",
2915 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2917 /* Verify if configured. This doesn't give much security, but it does
2918 make some people happy to be able to do it. If helo_required is set,
2919 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2920 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2921 now obsolescent, since the verification can now be requested selectively
2924 helo_verified = helo_verify_failed = FALSE;
2925 if (helo_required || helo_verify)
2927 BOOL tempfail = !smtp_verify_helo();
2932 smtp_printf("%d %s argument does not match calling host\r\n",
2933 tempfail? 451 : 550, hello);
2934 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2935 tempfail? "temporarily " : "",
2936 hello, sender_helo_name, host_and_ident(FALSE));
2937 helo_verified = old_helo_verified;
2938 break; /* End of HELO/EHLO processing */
2940 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2941 "helo_try_verify_hosts\n", hello);
2946 #ifdef EXPERIMENTAL_SPF
2947 /* set up SPF context */
2948 spf_init(sender_helo_name, sender_host_address);
2951 /* Apply an ACL check if one is defined; afterwards, recheck
2952 synchronization in case the client started sending in a delay. */
2954 if (acl_smtp_helo != NULL)
2956 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2959 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2960 sender_helo_name = NULL;
2961 host_build_sender_fullhost(); /* Rebuild */
2964 else if (!check_sync()) goto SYNC_FAILURE;
2967 /* Generate an OK reply. The default string includes the ident if present,
2968 and also the IP address if present. Reflecting back the ident is intended
2969 as a deterrent to mail forgers. For maximum efficiency, and also because
2970 some broken systems expect each response to be in a single packet, arrange
2971 that the entire reply is sent in one write(). */
2973 auth_advertised = FALSE;
2974 pipelining_advertised = FALSE;
2976 tls_advertised = FALSE;
2979 smtp_code = US"250 "; /* Default response code plus space*/
2980 if (user_msg == NULL)
2982 s = string_sprintf("%.3s %s Hello %s%s%s",
2984 smtp_active_hostname,
2985 (sender_ident == NULL)? US"" : sender_ident,
2986 (sender_ident == NULL)? US"" : US" at ",
2987 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2992 if (sender_host_address != NULL)
2994 s = string_cat(s, &size, &ptr, US" [", 2);
2995 s = string_cat(s, &size, &ptr, sender_host_address,
2996 Ustrlen(sender_host_address));
2997 s = string_cat(s, &size, &ptr, US"]", 1);
3001 /* A user-supplied EHLO greeting may not contain more than one line. Note
3002 that the code returned by smtp_message_code() includes the terminating
3003 whitespace character. */
3009 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3010 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3011 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3013 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3014 "newlines: message truncated: %s", string_printing(s));
3021 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3023 /* If we received EHLO, we must create a multiline response which includes
3024 the functions supported. */
3030 /* I'm not entirely happy with this, as an MTA is supposed to check
3031 that it has enough room to accept a message of maximum size before
3032 it sends this. However, there seems little point in not sending it.
3033 The actual size check happens later at MAIL FROM time. By postponing it
3034 till then, VRFY and EXPN can be used after EHLO when space is short. */
3036 if (thismessage_size_limit > 0)
3038 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3039 thismessage_size_limit);
3040 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3044 s = string_cat(s, &size, &ptr, smtp_code, 3);
3045 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3048 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3049 clean; if it has an 8-bit character in its hand, it just sends it. It
3050 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3051 However, some users want this option simply in order to stop MUAs
3052 mangling messages that contain top-bit-set characters. It is therefore
3053 provided as an option. */
3055 if (accept_8bitmime)
3057 s = string_cat(s, &size, &ptr, smtp_code, 3);
3058 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3061 /* Advertise ETRN if there's an ACL checking whether a host is
3062 permitted to issue it; a check is made when any host actually tries. */
3064 if (acl_smtp_etrn != NULL)
3066 s = string_cat(s, &size, &ptr, smtp_code, 3);
3067 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3070 /* Advertise EXPN if there's an ACL checking whether a host is
3071 permitted to issue it; a check is made when any host actually tries. */
3073 if (acl_smtp_expn != NULL)
3075 s = string_cat(s, &size, &ptr, smtp_code, 3);
3076 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3079 /* Exim is quite happy with pipelining, so let the other end know that
3080 it is safe to use it, unless advertising is disabled. */
3082 if (pipelining_enable &&
3083 verify_check_host(&pipelining_advertise_hosts) == OK)
3085 s = string_cat(s, &size, &ptr, smtp_code, 3);
3086 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3087 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3088 pipelining_advertised = TRUE;
3091 /* If any server authentication mechanisms are configured, advertise
3092 them if the current host is in auth_advertise_hosts. The problem with
3093 advertising always is that some clients then require users to
3094 authenticate (and aren't configurable otherwise) even though it may not
3095 be necessary (e.g. if the host is in host_accept_relay).
3097 RFC 2222 states that SASL mechanism names contain only upper case
3098 letters, so output the names in upper case, though we actually recognize
3099 them in either case in the AUTH command. */
3103 if (verify_check_host(&auth_advertise_hosts) == OK)
3107 for (au = auths; au != NULL; au = au->next)
3109 if (au->server && (au->advertise_condition == NULL ||
3110 expand_check_condition(au->advertise_condition, au->name,
3111 US"authenticator")))
3116 s = string_cat(s, &size, &ptr, smtp_code, 3);
3117 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3119 auth_advertised = TRUE;
3122 s = string_cat(s, &size, &ptr, US" ", 1);
3123 s = string_cat(s, &size, &ptr, au->public_name,
3124 Ustrlen(au->public_name));
3125 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3126 au->advertised = TRUE;
3128 else au->advertised = FALSE;
3130 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3134 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3135 if it has been included in the binary, and the host matches
3136 tls_advertise_hosts. We must *not* advertise if we are already in a
3137 secure connection. */
3140 if (tls_active < 0 &&
3141 verify_check_host(&tls_advertise_hosts) != FAIL)
3143 s = string_cat(s, &size, &ptr, smtp_code, 3);
3144 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3145 tls_advertised = TRUE;
3149 /* Finish off the multiline reply with one that is always available. */
3151 s = string_cat(s, &size, &ptr, smtp_code, 3);
3152 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3155 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3161 if (tls_active >= 0) (void)tls_write(s, ptr); else
3164 (void)fwrite(s, 1, ptr, smtp_out);
3168 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3169 memmove(cr, cr + 1, (ptr--) - (cr - s));
3170 debug_printf("SMTP>> %s", s);
3174 /* Reset the protocol and the state, abandoning any previous message. */
3176 received_protocol = (esmtp?
3178 ((sender_host_authenticated != NULL)? pauthed : 0) +
3179 ((tls_active >= 0)? pcrpted : 0)]
3181 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
3183 ((sender_host_address != NULL)? pnlocal : 0);
3185 smtp_reset(reset_point);
3187 break; /* HELO/EHLO */
3190 /* The MAIL command requires an address as an operand. All we do
3191 here is to parse it for syntactic correctness. The form "<>" is
3192 a special case which converts into an empty string. The start/end
3193 pointers in the original are not used further for this address, as
3194 it is the canonical extracted address which is all that is kept. */
3198 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3199 was_rej_mail = TRUE; /* Reset if accepted */
3201 if (helo_required && !helo_seen)
3203 smtp_printf("503 HELO or EHLO required\r\n");
3204 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3205 "HELO/EHLO given", host_and_ident(FALSE));
3209 if (sender_address != NULL)
3211 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3212 US"sender already given");
3216 if (smtp_cmd_data[0] == 0)
3218 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3219 US"MAIL must have an address operand");
3223 /* Check to see if the limit for messages per connection would be
3224 exceeded by accepting further messages. */
3226 if (smtp_accept_max_per_connection > 0 &&
3227 smtp_mailcmd_count > smtp_accept_max_per_connection)
3229 smtp_printf("421 too many messages in this connection\r\n");
3230 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3231 "messages in one connection", host_and_ident(TRUE));
3235 /* Reset for start of message - even if this is going to fail, we
3236 obviously need to throw away any previous data. */
3238 smtp_reset(reset_point);
3240 sender_data = recipient_data = NULL;
3242 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3246 uschar *name, *value, *end;
3247 unsigned long int size;
3249 if (!extract_option(&name, &value)) break;
3251 /* Handle SIZE= by reading the value. We don't do the check till later,
3252 in order to be able to log the sender address on failure. */
3254 if (strcmpic(name, US"SIZE") == 0 &&
3255 ((size = Ustrtoul(value, &end, 10)), *end == 0))
3257 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3259 message_size = (int)size;
3262 /* If this session was initiated with EHLO and accept_8bitmime is set,
3263 Exim will have indicated that it supports the BODY=8BITMIME option. In
3264 fact, it does not support this according to the RFCs, in that it does not
3265 take any special action for forwarding messages containing 8-bit
3266 characters. That is why accept_8bitmime is not the default setting, but
3267 some sites want the action that is provided. We recognize both "8BITMIME"
3268 and "7BIT" as body types, but take no action. */
3270 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
3271 (strcmpic(value, US"8BITMIME") == 0 ||
3272 strcmpic(value, US"7BIT") == 0)) {}
3274 /* Handle the AUTH extension. If the value given is not "<>" and either
3275 the ACL says "yes" or there is no ACL but the sending host is
3276 authenticated, we set it up as the authenticated sender. However, if the
3277 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3278 the condition is met. The value of AUTH is an xtext, which means that +,
3279 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3282 else if (strcmpic(name, US"AUTH") == 0)
3284 if (Ustrcmp(value, "<>") != 0)
3289 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3291 /* Put back terminator overrides for error message */
3294 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3295 US"invalid data for AUTH");
3299 if (acl_smtp_mailauth == NULL)
3301 ignore_msg = US"client not authenticated";
3302 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3306 ignore_msg = US"rejected by ACL";
3307 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3308 &user_msg, &log_msg);
3314 if (authenticated_by == NULL ||
3315 authenticated_by->mail_auth_condition == NULL ||
3316 expand_check_condition(authenticated_by->mail_auth_condition,
3317 authenticated_by->name, US"authenticator"))
3318 break; /* Accept the AUTH */
3320 ignore_msg = US"server_mail_auth_condition failed";
3321 if (authenticated_id != NULL)
3322 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3323 ignore_msg, authenticated_id);
3328 authenticated_sender = NULL;
3329 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3330 value, host_and_ident(TRUE), ignore_msg);
3333 /* Should only get DEFER or ERROR here. Put back terminator
3334 overrides for error message */
3339 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3346 /* Unknown option. Stick back the terminator characters and break
3347 the loop. An error for a malformed address will occur. */
3357 /* If we have passed the threshold for rate limiting, apply the current
3358 delay, and update it for next time, provided this is a limited host. */
3360 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3361 verify_check_host(&smtp_ratelimit_hosts) == OK)
3363 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3364 smtp_delay_mail/1000.0);
3365 millisleep((int)smtp_delay_mail);
3366 smtp_delay_mail *= smtp_rlm_factor;
3367 if (smtp_delay_mail > (double)smtp_rlm_limit)
3368 smtp_delay_mail = (double)smtp_rlm_limit;
3371 /* Now extract the address, first applying any SMTP-time rewriting. The
3372 TRUE flag allows "<>" as a sender address. */
3374 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3375 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3376 global_rewrite_rules) : smtp_cmd_data;
3378 /* rfc821_domains = TRUE; << no longer needed */
3380 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3382 /* rfc821_domains = FALSE; << no longer needed */
3384 if (raw_sender == NULL)
3386 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3390 sender_address = raw_sender;
3392 /* If there is a configured size limit for mail, check that this message
3393 doesn't exceed it. The check is postponed to this point so that the sender
3396 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3398 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3399 log_write(L_size_reject,
3400 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3401 "message too big: size%s=%d max=%d",
3403 host_and_ident(TRUE),
3404 (message_size == INT_MAX)? ">" : "",
3406 thismessage_size_limit);
3407 sender_address = NULL;
3411 /* Check there is enough space on the disk unless configured not to.
3412 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3413 plus the current message - i.e. we accept the message only if it won't
3414 reduce the space below the threshold. Add 5000 to the size to allow for
3415 overheads such as the Received: line and storing of recipients, etc.
3416 By putting the check here, even when SIZE is not given, it allow VRFY
3417 and EXPN etc. to be used when space is short. */
3419 if (!receive_check_fs(
3420 (smtp_check_spool_space && message_size >= 0)?
3421 message_size + 5000 : 0))
3423 smtp_printf("452 Space shortage, please try later\r\n");
3424 sender_address = NULL;
3428 /* If sender_address is unqualified, reject it, unless this is a locally
3429 generated message, or the sending host or net is permitted to send
3430 unqualified addresses - typically local machines behaving as MUAs -
3431 in which case just qualify the address. The flag is set above at the start
3432 of the SMTP connection. */
3434 if (sender_domain == 0 && sender_address[0] != 0)
3436 if (allow_unqualified_sender)
3438 sender_domain = Ustrlen(sender_address) + 1;
3439 sender_address = rewrite_address_qualify(sender_address, FALSE);
3440 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3445 smtp_printf("501 %s: sender address must contain a domain\r\n",
3447 log_write(L_smtp_syntax_error,
3448 LOG_MAIN|LOG_REJECT,
3449 "unqualified sender rejected: <%s> %s%s",
3451 host_and_ident(TRUE),
3453 sender_address = NULL;
3458 /* Apply an ACL check if one is defined, before responding. Afterwards,
3459 when pipelining is not advertised, do another sync check in case the ACL
3460 delayed and the client started sending in the meantime. */
3462 if (acl_smtp_mail == NULL) rc = OK; else
3464 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3465 if (rc == OK && !pipelining_advertised && !check_sync())
3469 if (rc == OK || rc == DISCARD)
3471 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3472 else smtp_user_msg(US"250", user_msg);
3473 smtp_delay_rcpt = smtp_rlr_base;
3474 recipients_discarded = (rc == DISCARD);
3475 was_rej_mail = FALSE;
3479 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3480 sender_address = NULL;
3485 /* The RCPT command requires an address as an operand. There may be any
3486 number of RCPT commands, specifying multiple recipients. We build them all
3487 into a data structure. The start/end values given by parse_extract_address
3488 are not used, as we keep only the extracted address. */
3493 was_rcpt = rcpt_in_progress = TRUE;
3495 /* There must be a sender address; if the sender was rejected and
3496 pipelining was advertised, we assume the client was pipelining, and do not
3497 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3498 get the same treatment. */
3500 if (sender_address == NULL)
3502 if (pipelining_advertised && last_was_rej_mail)
3504 smtp_printf("503 sender not yet given\r\n");
3505 was_rej_mail = TRUE;
3509 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3510 US"sender not yet given");
3511 was_rcpt = FALSE; /* Not a valid RCPT */
3517 /* Check for an operand */
3519 if (smtp_cmd_data[0] == 0)
3521 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3522 US"RCPT must have an address operand");
3527 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3528 as a recipient address */
3530 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3531 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3532 global_rewrite_rules) : smtp_cmd_data;
3534 /* rfc821_domains = TRUE; << no longer needed */
3535 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3536 &recipient_domain, FALSE);
3537 /* rfc821_domains = FALSE; << no longer needed */
3539 if (recipient == NULL)
3541 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3546 /* If the recipient address is unqualified, reject it, unless this is a
3547 locally generated message. However, unqualified addresses are permitted
3548 from a configured list of hosts and nets - typically when behaving as
3549 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3550 really. The flag is set at the start of the SMTP connection.
3552 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3553 assumed this meant "reserved local part", but the revision of RFC 821 and
3554 friends now makes it absolutely clear that it means *mailbox*. Consequently
3555 we must always qualify this address, regardless. */
3557 if (recipient_domain == 0)
3559 if (allow_unqualified_recipient ||
3560 strcmpic(recipient, US"postmaster") == 0)
3562 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3564 recipient_domain = Ustrlen(recipient) + 1;
3565 recipient = rewrite_address_qualify(recipient, TRUE);
3570 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3572 log_write(L_smtp_syntax_error,
3573 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3574 "<%s> %s%s", recipient, host_and_ident(TRUE),
3580 /* Check maximum allowed */
3582 if (rcpt_count > recipients_max && recipients_max > 0)
3584 if (recipients_max_reject)
3587 smtp_printf("552 too many recipients\r\n");
3589 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3590 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3595 smtp_printf("452 too many recipients\r\n");
3597 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3598 "temporarily rejected: sender=<%s> %s", sender_address,
3599 host_and_ident(TRUE));
3606 /* If we have passed the threshold for rate limiting, apply the current
3607 delay, and update it for next time, provided this is a limited host. */
3609 if (rcpt_count > smtp_rlr_threshold &&
3610 verify_check_host(&smtp_ratelimit_hosts) == OK)
3612 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3613 smtp_delay_rcpt/1000.0);
3614 millisleep((int)smtp_delay_rcpt);
3615 smtp_delay_rcpt *= smtp_rlr_factor;
3616 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3617 smtp_delay_rcpt = (double)smtp_rlr_limit;
3620 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3621 for them. Otherwise, check the access control list for this recipient. As
3622 there may be a delay in this, re-check for a synchronization error
3623 afterwards, unless pipelining was advertised. */
3625 if (recipients_discarded) rc = DISCARD; else
3627 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
3629 if (rc == OK && !pipelining_advertised && !check_sync())
3633 /* The ACL was happy */
3637 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3638 else smtp_user_msg(US"250", user_msg);
3639 receive_add_recipient(recipient, -1);
3642 /* The recipient was discarded */
3644 else if (rc == DISCARD)
3646 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3647 else smtp_user_msg(US"250", user_msg);
3650 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3651 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3652 (sender_address_unrewritten != NULL)?
3653 sender_address_unrewritten : sender_address,
3654 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3655 (log_msg == NULL)? US"" : US": ",
3656 (log_msg == NULL)? US"" : log_msg);
3659 /* Either the ACL failed the address, or it was deferred. */
3663 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3664 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3669 /* The DATA command is legal only if it follows successful MAIL FROM
3670 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3671 not counted as a protocol error if it follows RCPT (which must have been
3672 rejected if there are no recipients.) This function is complete when a
3673 valid DATA command is encountered.
3675 Note concerning the code used: RFC 2821 says this:
3677 - If there was no MAIL, or no RCPT, command, or all such commands
3678 were rejected, the server MAY return a "command out of sequence"
3679 (503) or "no valid recipients" (554) reply in response to the
3682 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3683 because it is the same whether pipelining is in use or not.
3685 If all the RCPT commands that precede DATA provoked the same error message
3686 (often indicating some kind of system error), it is helpful to include it
3687 with the DATA rejection (an idea suggested by Tony Finch). */
3691 if (!discarded && recipients_count <= 0)
3693 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
3695 uschar *code = US"503";
3696 int len = Ustrlen(rcpt_smtp_response);
3697 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
3699 /* Responses from smtp_printf() will have \r\n on the end */
3700 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
3701 rcpt_smtp_response[len-2] = 0;
3702 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
3704 if (pipelining_advertised && last_was_rcpt)
3705 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
3707 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3708 US"valid RCPT command must precede DATA");
3712 if (toomany && recipients_max_reject)
3714 sender_address = NULL; /* This will allow a new MAIL without RSET */
3715 sender_address_unrewritten = NULL;
3716 smtp_printf("554 Too many recipients\r\n");
3720 /* If there is an ACL, re-check the synchronization afterwards, since the
3721 ACL may have delayed. */
3723 if (acl_smtp_predata == NULL) rc = OK; else
3725 enable_dollar_recipients = TRUE;
3726 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3728 enable_dollar_recipients = FALSE;
3729 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
3734 if (user_msg == NULL)
3735 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3736 else smtp_user_msg(US"354", user_msg);
3738 message_ended = END_NOTENDED; /* Indicate in middle of data */
3741 /* Either the ACL failed the address, or it was deferred. */
3744 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3750 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3752 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3758 /* rfc821_domains = TRUE; << no longer needed */
3759 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
3760 &recipient_domain, FALSE);
3761 /* rfc821_domains = FALSE; << no longer needed */
3763 if (address == NULL)
3764 s = string_sprintf("501 %s", errmess);
3767 address_item *addr = deliver_make_addr(address, FALSE);
3768 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3769 -1, -1, NULL, NULL, NULL))
3772 s = string_sprintf("250 <%s> is deliverable", address);
3776 s = (addr->user_message != NULL)?
3777 string_sprintf("451 <%s> %s", address, addr->user_message) :
3778 string_sprintf("451 Cannot resolve <%s> at this time", address);
3782 s = (addr->user_message != NULL)?
3783 string_sprintf("550 <%s> %s", address, addr->user_message) :
3784 string_sprintf("550 <%s> is not deliverable", address);
3785 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3786 smtp_cmd_argument, host_and_ident(TRUE));
3791 smtp_printf("%s\r\n", s);
3798 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3800 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3803 BOOL save_log_testing_mode = log_testing_mode;
3804 address_test_mode = log_testing_mode = TRUE;
3805 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
3806 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3808 address_test_mode = FALSE;
3809 log_testing_mode = save_log_testing_mode; /* true for -bh */
3818 if (!tls_advertised)
3820 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3821 US"STARTTLS command used when not advertised");
3825 /* Apply an ACL check if one is defined */
3827 if (acl_smtp_starttls != NULL)
3829 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3833 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3838 /* RFC 2487 is not clear on when this command may be sent, though it
3839 does state that all information previously obtained from the client
3840 must be discarded if a TLS session is started. It seems reasonble to
3841 do an implied RSET when STARTTLS is received. */
3843 incomplete_transaction_log(US"STARTTLS");
3844 smtp_reset(reset_point);
3846 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3848 /* Attempt to start up a TLS session, and if successful, discard all
3849 knowledge that was obtained previously. At least, that's what the RFC says,
3850 and that's what happens by default. However, in order to work round YAEB,
3851 there is an option to remember the esmtp state. Sigh.
3853 We must allow for an extra EHLO command and an extra AUTH command after
3854 STARTTLS that don't add to the nonmail command count. */
3856 if ((rc = tls_server_start(tls_require_ciphers, gnutls_require_mac,
3857 gnutls_require_kx, gnutls_require_proto)) == OK)
3859 if (!tls_remember_esmtp)
3860 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3861 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3862 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3863 if (sender_helo_name != NULL)
3865 store_free(sender_helo_name);
3866 sender_helo_name = NULL;
3867 host_build_sender_fullhost(); /* Rebuild */
3868 set_process_info("handling incoming TLS connection from %s",
3869 host_and_ident(FALSE));
3871 received_protocol = (esmtp?
3872 protocols[pextend + pcrpted +
3873 ((sender_host_authenticated != NULL)? pauthed : 0)]
3875 protocols[pnormal + pcrpted])
3877 ((sender_host_address != NULL)? pnlocal : 0);
3879 sender_host_authenticated = NULL;
3880 authenticated_id = NULL;
3881 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3882 DEBUG(D_tls) debug_printf("TLS active\n");
3883 break; /* Successful STARTTLS */
3886 /* Some local configuration problem was discovered before actually trying
3887 to do a TLS handshake; give a temporary error. */
3889 else if (rc == DEFER)
3891 smtp_printf("454 TLS currently unavailable\r\n");
3895 /* Hard failure. Reject everything except QUIT or closed connection. One
3896 cause for failure is a nested STARTTLS, in which case tls_active remains
3897 set, but we must still reject all incoming commands. */
3899 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3902 switch(smtp_read_command(FALSE))
3905 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3906 smtp_get_connection_info());
3907 smtp_notquit_exit(US"tls-failed", NULL, NULL);
3911 /* It is perhaps arguable as to which exit ACL should be called here,
3912 but as it is probably a situtation that almost never arises, it
3913 probably doesn't matter. We choose to call the real QUIT ACL, which in
3914 some sense is perhaps "right". */
3918 if (acl_smtp_quit != NULL)
3920 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
3923 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3926 if (user_msg == NULL)
3927 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3929 smtp_respond(US"221", 3, TRUE, user_msg);
3930 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3931 smtp_get_connection_info());
3936 smtp_printf("554 Security failure\r\n");
3945 /* The ACL for QUIT is provided for gathering statistical information or
3946 similar; it does not affect the response code, but it can supply a custom
3951 incomplete_transaction_log(US"QUIT");
3952 if (acl_smtp_quit != NULL)
3954 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
3956 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3959 if (user_msg == NULL)
3960 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3962 smtp_respond(US"221", 3, TRUE, user_msg);
3969 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3970 smtp_get_connection_info());
3976 incomplete_transaction_log(US"RSET");
3977 smtp_reset(reset_point);
3979 smtp_printf("250 Reset OK\r\n");
3980 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3986 smtp_printf("250 OK\r\n");
3990 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
3991 used, a check will be done for permitted hosts. Show STARTTLS only if not
3992 already in a TLS session and if it would be advertised in the EHLO
3997 smtp_printf("214-Commands supported:\r\n");
4001 Ustrcat(buffer, " AUTH");
4003 if (tls_active < 0 &&
4004 verify_check_host(&tls_advertise_hosts) != FAIL)
4005 Ustrcat(buffer, " STARTTLS");
4007 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
4008 Ustrcat(buffer, " NOOP QUIT RSET HELP");
4009 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4010 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4011 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4012 smtp_printf("214%s\r\n", buffer);
4018 incomplete_transaction_log(US"connection lost");
4019 smtp_notquit_exit(US"connection-lost", US"421",
4020 US"%s lost input connection", smtp_active_hostname);
4022 /* Don't log by default unless in the middle of a message, as some mailers
4023 just drop the call rather than sending QUIT, and it clutters up the logs.
4026 if (sender_address != NULL || recipients_count > 0)
4027 log_write(L_lost_incoming_connection,
4029 "unexpected %s while reading SMTP command from %s%s",
4030 sender_host_unknown? "EOF" : "disconnection",
4031 host_and_ident(FALSE), smtp_read_error);
4033 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4034 smtp_get_connection_info(), smtp_read_error);
4042 if (sender_address != NULL)
4044 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4045 US"ETRN is not permitted inside a transaction");
4049 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4050 host_and_ident(FALSE));
4052 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4055 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4059 /* Compute the serialization key for this command. */
4061 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4063 /* If a command has been specified for running as a result of ETRN, we
4064 permit any argument to ETRN. If not, only the # standard form is permitted,
4065 since that is strictly the only kind of ETRN that can be implemented
4066 according to the RFC. */
4068 if (smtp_etrn_command != NULL)
4072 etrn_command = smtp_etrn_command;
4073 deliver_domain = smtp_cmd_data;
4074 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4075 US"ETRN processing", &error);
4076 deliver_domain = NULL;
4079 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4081 smtp_printf("458 Internal failure\r\n");
4086 /* Else set up to call Exim with the -R option. */
4090 if (*smtp_cmd_data++ != '#')
4092 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4093 US"argument must begin with #");
4096 etrn_command = US"exim -R";
4097 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4101 /* If we are host-testing, don't actually do anything. */
4107 debug_printf("ETRN command is: %s\n", etrn_command);
4108 debug_printf("ETRN command execution skipped\n");
4110 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4111 else smtp_user_msg(US"250", user_msg);
4116 /* If ETRN queue runs are to be serialized, check the database to
4117 ensure one isn't already running. */
4119 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4121 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4125 /* Fork a child process and run the command. We don't want to have to
4126 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4127 forking. It should be set that way anyway for external incoming SMTP,
4128 but we save and restore to be tidy. If serialization is required, we
4129 actually run the command in yet another process, so we can wait for it
4130 to complete and then remove the serialization lock. */
4132 oldsignal = signal(SIGCHLD, SIG_IGN);
4134 if ((pid = fork()) == 0)
4136 smtp_input = FALSE; /* This process is not associated with the */
4137 (void)fclose(smtp_in); /* SMTP call any more. */
4138 (void)fclose(smtp_out);
4140 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
4142 /* If not serializing, do the exec right away. Otherwise, fork down
4143 into another process. */
4145 if (!smtp_etrn_serialize || (pid = fork()) == 0)
4147 DEBUG(D_exec) debug_print_argv(argv);
4148 exim_nullstd(); /* Ensure std{in,out,err} exist */
4149 execv(CS argv[0], (char *const *)argv);
4150 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
4151 etrn_command, strerror(errno));
4152 _exit(EXIT_FAILURE); /* paranoia */
4155 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4156 is, we are in the first subprocess, after forking again. All we can do
4157 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4158 complete, before removing the serialization. */
4161 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4162 "failed: %s", strerror(errno));
4166 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4168 (void)wait(&status);
4169 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4173 enq_end(etrn_serialize_key);
4174 _exit(EXIT_SUCCESS);
4177 /* Back in the top level SMTP process. Check that we started a subprocess
4178 and restore the signal state. */
4182 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4184 smtp_printf("458 Unable to fork process\r\n");
4185 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4189 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4190 else smtp_user_msg(US"250", user_msg);
4193 signal(SIGCHLD, oldsignal);
4198 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4199 US"unexpected argument data");
4203 /* This currently happens only for NULLs, but could be extended. */
4206 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
4207 US"NULL character(s) present (shown as '?')");
4208 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
4214 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
4215 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
4216 c = smtp_inend - smtp_inptr;
4217 if (c > 150) c = 150;
4219 incomplete_transaction_log(US"sync failure");
4220 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
4221 "(next input sent too soon: pipelining was%s advertised): "
4222 "rejected \"%s\" %s next input=\"%s\"",
4223 pipelining_advertised? "" : " not",
4224 smtp_cmd_buffer, host_and_ident(TRUE),
4225 string_printing(smtp_inptr));
4226 smtp_notquit_exit(US"synchronization-error", US"554",
4227 US"SMTP synchronization error");
4228 done = 1; /* Pretend eof - drops connection */
4232 case TOO_MANY_NONMAIL_CMD:
4233 s = smtp_cmd_buffer;
4234 while (*s != 0 && !isspace(*s)) s++;
4235 incomplete_transaction_log(US"too many non-mail commands");
4236 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4237 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
4238 s - smtp_cmd_buffer, smtp_cmd_buffer);
4239 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
4240 done = 1; /* Pretend eof - drops connection */
4245 if (unknown_command_count++ >= smtp_max_unknown_commands)
4247 log_write(L_smtp_syntax_error, LOG_MAIN,
4248 "SMTP syntax error in \"%s\" %s %s",
4249 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
4250 US"unrecognized command");
4251 incomplete_transaction_log(US"unrecognized command");
4252 smtp_notquit_exit(US"bad-commands", US"500",
4253 US"Too many unrecognized commands");
4255 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4256 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
4260 done = synprot_error(L_smtp_syntax_error, 500, NULL,
4261 US"unrecognized command");
4265 /* This label is used by goto's inside loops that want to break out to
4266 the end of the command-processing loop. */
4269 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
4270 last_was_rcpt = was_rcpt; /* protocol error handling */
4274 return done - 2; /* Convert yield values */
4277 /* End of smtp_in.c */
git://git.exim.org / exim.git / blob