1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.24 2005/09/07 10:15:33 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2005 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. */
42 #define cmd_buffer_size 2048
44 /* Size of buffer for reading SMTP incoming packets */
46 #define in_buffer_size 8192
48 /* Structure for SMTP command list */
55 short int is_mail_cmd;
58 /* Codes for identifying commands. We order them so that those that come first
59 are those for which synchronization is always required. Checking this can help
63 /* These commands are required to be synchronized, i.e. to be the last in a
64 block of commands when pipelining. */
66 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
67 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
68 ETRN_CMD, /* This by analogy with TURN from the RFC */
69 STARTTLS_CMD, /* Required by the STARTTLS RFC */
71 /* This is a dummy to identify the non-sync commands when pipelining */
73 NON_SYNC_CMD_PIPELINING,
75 /* These commands need not be synchronized when pipelining */
77 MAIL_CMD, RCPT_CMD, RSET_CMD,
79 /* This is a dummy to identify the non-sync commands when not pipelining */
81 NON_SYNC_CMD_NON_PIPELINING,
83 /* I have been unable to find a statement about the use of pipelining
84 with AUTH, so to be on the safe side it is here, though I kind of feel
85 it should be up there with the synchronized commands. */
89 /* I'm not sure about these, but I don't think they matter. */
93 /* These are specials that don't correspond to actual commands */
95 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
96 TOO_MANY_NONMAIL_CMD };
100 /*************************************************
101 * Local static variables *
102 *************************************************/
104 static auth_instance *authenticated_by;
105 static BOOL auth_advertised;
107 static BOOL tls_advertised;
110 static BOOL helo_required = FALSE;
111 static BOOL helo_verify = FALSE;
112 static BOOL helo_seen;
113 static BOOL helo_accept_junk;
114 static BOOL count_nonmail;
115 static BOOL pipelining_advertised;
116 static int nonmail_command_count;
117 static int synprot_error_count;
118 static int unknown_command_count;
119 static int sync_cmd_limit;
120 static int smtp_write_error = 0;
122 static uschar *cmd_buffer;
124 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
125 final fields of all except AUTH are forced TRUE at the start of a new message
126 setup, to allow one of each between messages that is not counted as a nonmail
127 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
128 allow a new EHLO after starting up TLS.
130 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
131 counted. However, the flag is changed when AUTH is received, so that multiple
132 failing AUTHs will eventually hit the limit. After a successful AUTH, another
133 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
134 forced TRUE, to allow for the re-authentication that can happen at that point.
136 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
137 count of non-mail commands and possibly provoke an error. */
139 static smtp_cmd_list cmd_list[] = {
140 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
141 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
142 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
143 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
145 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
148 /* If you change anything above here, also fix the definitions below. */
150 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
151 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
152 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
153 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
154 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
155 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
156 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
157 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
158 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
161 static smtp_cmd_list *cmd_list_end =
162 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
164 #define CMD_LIST_RSET 0
165 #define CMD_LIST_HELO 1
166 #define CMD_LIST_EHLO 2
167 #define CMD_LIST_AUTH 3
168 #define CMD_LIST_STARTTLS 4
170 static uschar *protocols[] = {
171 US"local-smtp", /* HELO */
172 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
173 US"local-esmtp", /* EHLO */
174 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
175 US"local-esmtpa", /* EHLO->AUTH */
176 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
181 #define pcrpted 1 /* added to pextend or pnormal */
182 #define pauthed 2 /* added to pextend */
183 #define pnlocal 6 /* offset to remove "local" */
185 /* When reading SMTP from a remote host, we have to use our own versions of the
186 C input-reading functions, in order to be able to flush the SMTP output only
187 when about to read more data from the socket. This is the only way to get
188 optimal performance when the client is using pipelining. Flushing for every
189 command causes a separate packet and reply packet each time; saving all the
190 responses up (when pipelining) combines them into one packet and one response.
192 For simplicity, these functions are used for *all* SMTP input, not only when
193 receiving over a socket. However, after setting up a secure socket (SSL), input
194 is read via the OpenSSL library, and another set of functions is used instead
197 These functions are set in the receive_getc etc. variables and called with the
198 same interface as the C functions. However, since there can only ever be
199 one incoming SMTP call, we just use a single buffer and flags. There is no need
200 to implement a complicated private FILE-like structure.*/
202 static uschar *smtp_inbuffer;
203 static uschar *smtp_inptr;
204 static uschar *smtp_inend;
205 static int smtp_had_eof;
206 static int smtp_had_error;
209 /*************************************************
210 * SMTP version of getc() *
211 *************************************************/
213 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
214 it flushes the output, and refills the buffer, with a timeout. The signal
215 handler is set appropriately by the calling function. This function is not used
216 after a connection has negotated itself into an TLS/SSL state.
219 Returns: the next character or EOF
225 if (smtp_inptr >= smtp_inend)
229 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
230 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
235 /* Must put the error text in fixed store, because this might be during
236 header reading, where it releases unused store above the header. */
239 smtp_had_error = save_errno;
240 smtp_read_error = string_copy_malloc(
241 string_sprintf(" (error: %s)", strerror(save_errno)));
243 else smtp_had_eof = 1;
246 smtp_inend = smtp_inbuffer + rc;
247 smtp_inptr = smtp_inbuffer;
249 return *smtp_inptr++;
254 /*************************************************
255 * SMTP version of ungetc() *
256 *************************************************/
258 /* Puts a character back in the input buffer. Only ever
264 Returns: the character
270 *(--smtp_inptr) = ch;
277 /*************************************************
278 * SMTP version of feof() *
279 *************************************************/
281 /* Tests for a previous EOF
284 Returns: non-zero if the eof flag is set
296 /*************************************************
297 * SMTP version of ferror() *
298 *************************************************/
300 /* Tests for a previous read error, and returns with errno
301 restored to what it was when the error was detected.
304 Returns: non-zero if the error flag is set
310 errno = smtp_had_error;
311 return smtp_had_error;
317 /*************************************************
318 * Write formatted string to SMTP channel *
319 *************************************************/
321 /* This is a separate function so that we don't have to repeat everything for
322 TLS support or debugging. It is global so that the daemon and the
323 authentication functions can use it. It does not return any error indication,
324 because major problems such as dropped connections won't show up till an output
325 flush for non-TLS connections. The smtp_fflush() function is available for
326 checking that: for convenience, TLS output errors are remembered here so that
327 they are also picked up later by smtp_fflush().
331 ... optional arguments
337 smtp_printf(char *format, ...)
343 va_start(ap, format);
344 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
345 debug_printf("SMTP>> %s", big_buffer);
348 va_start(ap, format);
350 /* If in a TLS session we have to format the string, and then write it using a
356 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
358 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
359 smtp_closedown(US"Unexpected error");
360 exim_exit(EXIT_FAILURE);
362 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
367 /* Otherwise, just use the standard library function. */
369 if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
375 /*************************************************
376 * Flush SMTP out and check for error *
377 *************************************************/
379 /* This function isn't currently used within Exim (it detects errors when it
380 tries to read the next SMTP input), but is available for use in local_scan().
381 For non-TLS connections, it flushes the output and checks for errors. For
382 TLS-connections, it checks for a previously-detected TLS write error.
385 Returns: 0 for no error; -1 after an error
391 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
392 return smtp_write_error;
397 /*************************************************
398 * SMTP command read timeout *
399 *************************************************/
401 /* Signal handler for timing out incoming SMTP commands. This attempts to
404 Argument: signal number (SIGALRM)
409 command_timeout_handler(int sig)
411 sig = sig; /* Keep picky compilers happy */
412 log_write(L_lost_incoming_connection,
413 LOG_MAIN, "SMTP command timeout on%s connection from %s",
414 (tls_active >= 0)? " TLS" : "",
415 host_and_ident(FALSE));
416 if (smtp_batched_input)
417 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
418 smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
419 smtp_active_hostname);
421 exim_exit(EXIT_FAILURE);
426 /*************************************************
428 *************************************************/
430 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
432 Argument: signal number (SIGTERM)
437 command_sigterm_handler(int sig)
439 sig = sig; /* Keep picky compilers happy */
440 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
441 if (smtp_batched_input)
442 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
443 smtp_printf("421 %s: Service not available - closing connection\r\n",
444 smtp_active_hostname);
445 exim_exit(EXIT_FAILURE);
450 /*************************************************
451 * Read one command line *
452 *************************************************/
454 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
455 There are sites that don't do this, and in any case internal SMTP probably
456 should check only for LF. Consequently, we check here for LF only. The line
457 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
458 an unknown command. The command is read into the static cmd_buffer.
460 The character reading routine sets up a timeout for each block actually read
461 from the input (which may contain more than one command). We set up a special
462 signal handler that closes down the session on a timeout. Control does not
466 check_sync if TRUE, check synchronization rules if global option is TRUE
468 Returns: a code identifying the command (enumerated above)
472 smtp_read_command(BOOL check_sync)
477 BOOL hadnull = FALSE;
479 os_non_restarting_signal(SIGALRM, command_timeout_handler);
481 while ((c = (receive_getc)()) != '\n' && c != EOF)
483 if (ptr >= cmd_buffer_size)
485 os_non_restarting_signal(SIGALRM, sigalrm_handler);
493 cmd_buffer[ptr++] = c;
496 receive_linecount++; /* For BSMTP errors */
497 os_non_restarting_signal(SIGALRM, sigalrm_handler);
499 /* If hit end of file, return pseudo EOF command. Whether we have a
500 part-line already read doesn't matter, since this is an error state. */
502 if (c == EOF) return EOF_CMD;
504 /* Remove any CR and white space at the end of the line, and terminate the
507 while (ptr > 0 && isspace(cmd_buffer[ptr-1])) ptr--;
510 DEBUG(D_receive) debug_printf("SMTP<< %s\n", cmd_buffer);
512 /* NULLs are not allowed in SMTP commands */
514 if (hadnull) return BADCHAR_CMD;
516 /* Scan command list and return identity, having set the data pointer
517 to the start of the actual data characters. Check for SMTP synchronization
520 for (p = cmd_list; p < cmd_list_end; p++)
522 if (strncmpic(cmd_buffer, US p->name, p->len) == 0)
524 if (smtp_inptr < smtp_inend && /* Outstanding input */
525 p->cmd < sync_cmd_limit && /* Command should sync */
526 check_sync && /* Local flag set */
527 smtp_enforce_sync && /* Global flag set */
528 sender_host_address != NULL && /* Not local input */
529 !sender_host_notsocket) /* Really is a socket */
532 /* Point after the command, but don't skip over leading spaces till after
533 the following test, so that if it fails, the command name can easily be
536 smtp_command_argument = cmd_buffer + p->len;
538 /* Count non-mail commands from those hosts that are controlled in this
539 way. The default is all hosts. We don't waste effort checking the list
540 until we get a non-mail command, but then cache the result to save checking
541 again. If there's a DEFER while checking the host, assume it's in the list.
543 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
544 start of each incoming message by fiddling with the value in the table. */
548 if (count_nonmail == TRUE_UNSET) count_nonmail =
549 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
550 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
551 return TOO_MANY_NONMAIL_CMD;
554 /* Get the data pointer over leading spaces and return; if there is data
555 for a command that does not expect it, give the error centrally here. */
557 while (isspace(*smtp_command_argument)) smtp_command_argument++;
558 return (p->has_arg || *smtp_command_argument == 0)? p->cmd : BADARG_CMD;
562 /* Enforce synchronization for unknown commands */
564 if (smtp_inptr < smtp_inend && /* Outstanding input */
565 check_sync && /* Local flag set */
566 smtp_enforce_sync && /* Global flag set */
567 sender_host_address != NULL && /* Not local input */
568 !sender_host_notsocket) /* Really is a socket */
576 /*************************************************
577 * Forced closedown of call *
578 *************************************************/
580 /* This function is called from log.c when Exim is dying because of a serious
581 disaster, and also from some other places. If an incoming non-batched SMTP
582 channel is open, it swallows the rest of the incoming message if in the DATA
583 phase, sends the reply string, and gives an error to all subsequent commands
584 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
587 Argument: SMTP reply string to send, excluding the code
592 smtp_closedown(uschar *message)
594 if (smtp_in == NULL || smtp_batched_input) return;
595 receive_swallow_smtp();
596 smtp_printf("421 %s\r\n", message);
600 switch(smtp_read_command(FALSE))
606 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
611 smtp_printf("250 Reset OK\r\n");
615 smtp_printf("421 %s\r\n", message);
624 /*************************************************
625 * Set up connection info for logging *
626 *************************************************/
628 /* This function is called when logging information about an SMTP connection.
629 It sets up appropriate source information, depending on the type of connection.
632 Returns: a string describing the connection
636 smtp_get_connection_info(void)
639 return string_sprintf("SMTP connection from %s", sender_fullhost);
641 if (sender_host_unknown || sender_host_notsocket)
642 return string_sprintf("SMTP connection from %s", sender_ident);
645 return string_sprintf("SMTP connection from %s (via inetd)", sender_fullhost);
647 if ((log_extra_selector & LX_incoming_interface) != 0 &&
648 interface_address != NULL)
649 return string_sprintf("SMTP connection from %s I=[%s]:%d", sender_fullhost,
650 interface_address, interface_port);
652 return string_sprintf("SMTP connection from %s", sender_fullhost);
657 /*************************************************
658 * Check HELO line and set sender_helo_name *
659 *************************************************/
661 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
662 the domain name of the sending host, or an ip literal in square brackets. The
663 arrgument is placed in sender_helo_name, which is in malloc store, because it
664 must persist over multiple incoming messages. If helo_accept_junk is set, this
665 host is permitted to send any old junk (needed for some broken hosts).
666 Otherwise, helo_allow_chars can be used for rogue characters in general
667 (typically people want to let in underscores).
670 s the data portion of the line (already past any white space)
672 Returns: TRUE or FALSE
676 check_helo(uschar *s)
679 uschar *end = s + Ustrlen(s);
680 BOOL yield = helo_accept_junk;
682 /* Discard any previous helo name */
684 if (sender_helo_name != NULL)
686 store_free(sender_helo_name);
687 sender_helo_name = NULL;
690 /* Skip tests if junk is permitted. */
694 /* Allow the new standard form for IPv6 address literals, namely,
695 [IPv6:....], and because someone is bound to use it, allow an equivalent
696 IPv4 form. Allow plain addresses as well. */
703 if (strncmpic(s, US"[IPv6:", 6) == 0)
704 yield = (string_is_ip_address(s+6, NULL) == 6);
705 else if (strncmpic(s, US"[IPv4:", 6) == 0)
706 yield = (string_is_ip_address(s+6, NULL) == 4);
708 yield = (string_is_ip_address(s+1, NULL) != 0);
713 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
714 that have been configured (usually underscore - sigh). */
721 if (!isalnum(*s) && *s != '.' && *s != '-' &&
722 Ustrchr(helo_allow_chars, *s) == NULL)
732 /* Save argument if OK */
734 if (yield) sender_helo_name = string_copy_malloc(start);
742 /*************************************************
743 * Extract SMTP command option *
744 *************************************************/
746 /* This function picks the next option setting off the end of smtp_command_argument. It
747 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
748 things that can appear there.
751 name point this at the name
752 value point this at the data string
754 Returns: TRUE if found an option
758 extract_option(uschar **name, uschar **value)
761 uschar *v = smtp_command_argument + Ustrlen(smtp_command_argument) -1;
762 while (isspace(*v)) v--;
765 while (v > smtp_command_argument && *v != '=' && !isspace(*v)) v--;
766 if (*v != '=') return FALSE;
769 while(isalpha(n[-1])) n--;
771 if (n[-1] != ' ') return FALSE;
786 /*************************************************
787 * Reset for new message *
788 *************************************************/
790 /* This function is called whenever the SMTP session is reset from
791 within either of the setup functions.
793 Argument: the stacking pool storage reset point
798 smtp_reset(void *reset_point)
801 store_reset(reset_point);
802 recipients_list = NULL;
803 rcpt_count = rcpt_defer_count = rcpt_fail_count =
804 raw_recipients_count = recipients_count = recipients_list_max = 0;
805 message_linecount = 0;
807 acl_warn_headers = NULL;
808 queue_only_policy = FALSE;
809 deliver_freeze = FALSE; /* Can be set by ACL */
810 fake_response = OK; /* Can be set by ACL */
811 #ifdef WITH_CONTENT_SCAN
812 no_mbox_unspool = FALSE; /* Can be set by ACL */
814 submission_mode = FALSE; /* Can be set by ACL */
815 active_local_from_check = local_from_check; /* Can be set by ACL */
816 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
817 sender_address = NULL;
818 submission_name = NULL; /* Can be set by ACL */
819 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
820 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
821 sender_verified_list = NULL; /* No senders verified */
822 memset(sender_address_cache, 0, sizeof(sender_address_cache));
823 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
824 authenticated_sender = NULL;
825 #ifdef EXPERIMENTAL_BRIGHTMAIL
829 #ifdef EXPERIMENTAL_DOMAINKEYS
832 #ifdef EXPERIMENTAL_SPF
833 spf_header_comment = NULL;
836 spf_smtp_comment = NULL;
838 body_linecount = body_zerocount = 0;
840 sender_rate = sender_rate_limit = sender_rate_period = NULL;
841 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
842 /* Note that ratelimiters_conn persists across resets. */
844 for (i = 0; i < ACL_M_MAX; i++) acl_var[ACL_C_MAX + i] = NULL;
846 /* The message body variables use malloc store. They may be set if this is
847 not the first message in an SMTP session and the previous message caused them
848 to be referenced in an ACL. */
850 if (message_body != NULL)
852 store_free(message_body);
856 if (message_body_end != NULL)
858 store_free(message_body_end);
859 message_body_end = NULL;
862 /* Warning log messages are also saved in malloc store. They are saved to avoid
863 repetition in the same message, but it seems right to repeat them for different
866 while (acl_warn_logged != NULL)
868 string_item *this = acl_warn_logged;
869 acl_warn_logged = acl_warn_logged->next;
878 /*************************************************
879 * Initialize for incoming batched SMTP message *
880 *************************************************/
882 /* This function is called from smtp_setup_msg() in the case when
883 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
884 of messages in one file with SMTP commands between them. All errors must be
885 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
886 relevant. After an error on a sender, or an invalid recipient, the remainder
887 of the message is skipped. The value of received_protocol is already set.
890 Returns: > 0 message successfully started (reached DATA)
891 = 0 QUIT read or end of file reached
896 smtp_setup_batch_msg(void)
899 void *reset_point = store_get(0);
901 /* Save the line count at the start of each transaction - single commands
902 like HELO and RSET count as whole transactions. */
904 bsmtp_transaction_linecount = receive_linecount;
906 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
908 smtp_reset(reset_point); /* Reset for start of message */
910 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
911 value. The values are 2 larger than the required yield of the function. */
916 uschar *recipient = NULL;
917 int start, end, sender_domain, recipient_domain;
919 switch(smtp_read_command(FALSE))
921 /* The HELO/EHLO commands set sender_address_helo if they have
922 valid data; otherwise they are ignored, except that they do
923 a reset of the state. */
928 check_helo(smtp_command_argument);
932 smtp_reset(reset_point);
933 bsmtp_transaction_linecount = receive_linecount;
937 /* The MAIL FROM command requires an address as an operand. All we
938 do here is to parse it for syntactic correctness. The form "<>" is
939 a special case which converts into an empty string. The start/end
940 pointers in the original are not used further for this address, as
941 it is the canonical extracted address which is all that is kept. */
944 if (sender_address != NULL)
945 /* The function moan_smtp_batch() does not return. */
946 moan_smtp_batch(cmd_buffer, "503 Sender already given");
948 if (smtp_command_argument[0] == 0)
949 /* The function moan_smtp_batch() does not return. */
950 moan_smtp_batch(cmd_buffer, "501 MAIL FROM must have an address operand");
952 /* Reset to start of message */
954 smtp_reset(reset_point);
956 /* Apply SMTP rewrite */
958 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
959 rewrite_one(smtp_command_argument, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
960 US"", global_rewrite_rules) : smtp_command_argument;
962 /* Extract the address; the TRUE flag allows <> as valid */
965 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
968 if (raw_sender == NULL)
969 /* The function moan_smtp_batch() does not return. */
970 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
972 sender_address = string_copy(raw_sender);
974 /* Qualify unqualified sender addresses if permitted to do so. */
976 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
978 if (allow_unqualified_sender)
980 sender_address = rewrite_address_qualify(sender_address, FALSE);
981 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
982 "and rewritten\n", raw_sender);
984 /* The function moan_smtp_batch() does not return. */
985 else moan_smtp_batch(cmd_buffer, "501 sender address must contain "
991 /* The RCPT TO command requires an address as an operand. All we do
992 here is to parse it for syntactic correctness. There may be any number
993 of RCPT TO commands, specifying multiple senders. We build them all into
994 a data structure that is in argc/argv format. The start/end values
995 given by parse_extract_address are not used, as we keep only the
996 extracted address. */
999 if (sender_address == NULL)
1000 /* The function moan_smtp_batch() does not return. */
1001 moan_smtp_batch(cmd_buffer, "503 No sender yet given");
1003 if (smtp_command_argument[0] == 0)
1004 /* The function moan_smtp_batch() does not return. */
1005 moan_smtp_batch(cmd_buffer, "501 RCPT TO must have an address operand");
1007 /* Check maximum number allowed */
1009 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1010 /* The function moan_smtp_batch() does not return. */
1011 moan_smtp_batch(cmd_buffer, "%s too many recipients",
1012 recipients_max_reject? "552": "452");
1014 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1015 recipient address */
1017 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1018 rewrite_one(smtp_command_argument, rewrite_smtp, NULL, FALSE, US"",
1019 global_rewrite_rules) : smtp_command_argument;
1021 /* rfc821_domains = TRUE; << no longer needed */
1022 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1023 &recipient_domain, FALSE);
1024 /* rfc821_domains = FALSE; << no longer needed */
1026 if (recipient == NULL)
1027 /* The function moan_smtp_batch() does not return. */
1028 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
1030 /* If the recipient address is unqualified, qualify it if permitted. Then
1031 add it to the list of recipients. */
1033 if (recipient_domain == 0)
1035 if (allow_unqualified_recipient)
1037 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1039 recipient = rewrite_address_qualify(recipient, TRUE);
1041 /* The function moan_smtp_batch() does not return. */
1042 else moan_smtp_batch(cmd_buffer, "501 recipient address must contain "
1045 receive_add_recipient(recipient, -1);
1049 /* The DATA command is legal only if it follows successful MAIL FROM
1050 and RCPT TO commands. This function is complete when a valid DATA
1051 command is encountered. */
1054 if (sender_address == NULL || recipients_count <= 0)
1056 /* The function moan_smtp_batch() does not return. */
1057 if (sender_address == NULL)
1058 moan_smtp_batch(cmd_buffer,
1059 "503 MAIL FROM:<sender> command must precede DATA");
1061 moan_smtp_batch(cmd_buffer,
1062 "503 RCPT TO:<recipient> must precede DATA");
1066 done = 3; /* DATA successfully achieved */
1067 message_ended = END_NOTENDED; /* Indicate in middle of message */
1072 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1079 bsmtp_transaction_linecount = receive_linecount;
1090 /* The function moan_smtp_batch() does not return. */
1091 moan_smtp_batch(cmd_buffer, "501 Unexpected argument data");
1096 /* The function moan_smtp_batch() does not return. */
1097 moan_smtp_batch(cmd_buffer, "501 Unexpected NULL in SMTP command");
1102 /* The function moan_smtp_batch() does not return. */
1103 moan_smtp_batch(cmd_buffer, "500 Command unrecognized");
1108 return done - 2; /* Convert yield values */
1114 /*************************************************
1115 * Start an SMTP session *
1116 *************************************************/
1118 /* This function is called at the start of an SMTP session. Thereafter,
1119 smtp_setup_msg() is called to initiate each separate message. This
1120 function does host-specific testing, and outputs the banner line.
1123 Returns: FALSE if the session can not continue; something has
1124 gone wrong, or the connection to the host is blocked
1128 smtp_start_session(void)
1134 /* If we are running in the test harness, and the incoming call is from
1135 127.0.0.2 (sic), have a short delay. This makes it possible to test handling of
1136 input sent too soon (before the banner is output). */
1138 if (running_in_test_harness &&
1139 sender_host_address != NULL &&
1140 Ustrcmp(sender_host_address, "127.0.0.2") == 0)
1143 /* Default values for certain variables */
1145 helo_seen = esmtp = helo_accept_junk = FALSE;
1146 count_nonmail = TRUE_UNSET;
1147 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1148 smtp_delay_mail = smtp_rlm_base;
1149 auth_advertised = FALSE;
1150 pipelining_advertised = FALSE;
1151 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1153 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1155 sender_host_authenticated = NULL;
1156 authenticated_by = NULL;
1159 tls_cipher = tls_peerdn = NULL;
1160 tls_advertised = FALSE;
1163 /* Reset ACL connection variables */
1165 for (i = 0; i < ACL_C_MAX; i++) acl_var[i] = NULL;
1167 cmd_buffer = (uschar *)malloc(cmd_buffer_size + 1); /* allow for trailing 0 */
1168 if (cmd_buffer == NULL)
1169 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1170 "malloc() failed for SMTP command buffer");
1172 /* For batched input, the protocol setting can be overridden from the
1173 command line by a trusted caller. */
1175 if (smtp_batched_input)
1177 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1180 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1181 reset later if any of EHLO/AUTH/STARTTLS are received. */
1185 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1187 /* Set up the buffer for inputting using direct read() calls, and arrange to
1188 call the local functions instead of the standard C ones. */
1190 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1191 if (smtp_inbuffer == NULL)
1192 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1193 receive_getc = smtp_getc;
1194 receive_ungetc = smtp_ungetc;
1195 receive_feof = smtp_feof;
1196 receive_ferror = smtp_ferror;
1197 smtp_inptr = smtp_inend = smtp_inbuffer;
1198 smtp_had_eof = smtp_had_error = 0;
1200 /* Set up the message size limit; this may be host-specific */
1202 thismessage_size_limit = expand_string_integer(message_size_limit);
1203 if (thismessage_size_limit < 0)
1205 if (thismessage_size_limit == -1)
1206 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1207 "%s", expand_string_message);
1209 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1210 "%s", expand_string_message);
1211 smtp_closedown(US"Temporary local problem - please try later");
1215 /* When a message is input locally via the -bs or -bS options, sender_host_
1216 unknown is set unless -oMa was used to force an IP address, in which case it
1217 is checked like a real remote connection. When -bs is used from inetd, this
1218 flag is not set, causing the sending host to be checked. The code that deals
1219 with IP source routing (if configured) is never required for -bs or -bS and
1220 the flag sender_host_notsocket is used to suppress it.
1222 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1223 reserve for certain hosts and/or networks. */
1225 if (!sender_host_unknown)
1228 BOOL reserved_host = FALSE;
1230 /* Look up IP options (source routing info) on the socket if this is not an
1231 -oMa "host", and if any are found, log them and drop the connection.
1233 Linux (and others now, see below) is different to everyone else, so there
1234 has to be some conditional compilation here. Versions of Linux before 2.1.15
1235 used a structure whose name was "options". Somebody finally realized that
1236 this name was silly, and it got changed to "ip_options". I use the
1237 newer name here, but there is a fudge in the script that sets up os.h
1238 to define a macro in older Linux systems.
1240 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1241 glibc 2, which has chosen ip_opts for the structure name. This is now
1242 really a glibc thing rather than a Linux thing, so the condition name
1243 has been changed to reflect this. It is relevant also to GNU/Hurd.
1245 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1246 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1247 a special macro defined in the os.h file.
1249 Some DGUX versions on older hardware appear not to support IP options at
1250 all, so there is now a general macro which can be set to cut out this
1253 How to do this properly in IPv6 is not yet known. */
1255 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1257 #ifdef GLIBC_IP_OPTIONS
1258 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1263 #elif defined DARWIN_IP_OPTIONS
1269 if (!host_checking && !sender_host_notsocket)
1272 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1273 struct ip_options *ipopt = store_get(optlen);
1275 struct ip_opts ipoptblock;
1276 struct ip_opts *ipopt = &ipoptblock;
1277 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1279 struct ipoption ipoptblock;
1280 struct ipoption *ipopt = &ipoptblock;
1281 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1284 /* Occasional genuine failures of getsockopt() have been seen - for
1285 example, "reset by peer". Therefore, just log and give up on this
1286 call, unless the error is ENOPROTOOPT. This error is given by systems
1287 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1288 of writing. So for that error, carry on - we just can't do an IP options
1291 DEBUG(D_receive) debug_printf("checking for IP options\n");
1293 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1296 if (errno != ENOPROTOOPT)
1298 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1299 host_and_ident(FALSE), strerror(errno));
1300 smtp_printf("451 SMTP service not available\r\n");
1305 /* Deal with any IP options that are set. On the systems I have looked at,
1306 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1307 more logging data than will fit in big_buffer. Nevertheless, after somebody
1308 questioned this code, I've added in some paranoid checking. */
1310 else if (optlen > 0)
1312 uschar *p = big_buffer;
1313 uschar *pend = big_buffer + big_buffer_size;
1314 uschar *opt, *adptr;
1316 struct in_addr addr;
1319 uschar *optstart = (uschar *)(ipopt->__data);
1321 uschar *optstart = (uschar *)(ipopt->ip_opts);
1323 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1326 DEBUG(D_receive) debug_printf("IP options exist\n");
1328 Ustrcpy(p, "IP options on incoming call:");
1331 for (opt = optstart; opt != NULL &&
1332 opt < (uschar *)(ipopt) + optlen;)
1346 if (!string_format(p, pend-p, " %s [@%s",
1347 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1349 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1351 inet_ntoa(ipopt->ip_dst)))
1353 inet_ntoa(ipopt->ipopt_dst)))
1361 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1363 while (optcount-- > 0)
1365 memcpy(&addr, adptr, sizeof(addr));
1366 if (!string_format(p, pend - p - 1, "%s%s",
1367 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1373 adptr += sizeof(struct in_addr);
1382 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1385 for (i = 0; i < opt[1]; i++)
1387 sprintf(CS p, "%2.2x ", opt[i]);
1398 log_write(0, LOG_MAIN, "%s", big_buffer);
1400 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1402 log_write(0, LOG_MAIN|LOG_REJECT,
1403 "connection from %s refused (IP options)", host_and_ident(FALSE));
1405 smtp_printf("554 SMTP service not available\r\n");
1409 /* Length of options = 0 => there are no options */
1411 else DEBUG(D_receive) debug_printf("no IP options found\n");
1413 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1415 /* Set keep-alive in socket options. The option is on by default. This
1416 setting is an attempt to get rid of some hanging connections that stick in
1417 read() when the remote end (usually a dialup) goes away. */
1419 if (smtp_accept_keepalive && !sender_host_notsocket)
1420 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1422 /* If the current host matches host_lookup, set the name by doing a
1423 reverse lookup. On failure, sender_host_name will be NULL and
1424 host_lookup_failed will be TRUE. This may or may not be serious - optional
1427 if (verify_check_host(&host_lookup) == OK)
1429 (void)host_name_lookup();
1430 host_build_sender_fullhost();
1433 /* Delay this until we have the full name, if it is looked up. */
1435 set_process_info("handling incoming connection from %s",
1436 host_and_ident(FALSE));
1438 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1439 smtps port for use with older style SSL MTAs. */
1442 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1446 /* Test for explicit connection rejection */
1448 if (verify_check_host(&host_reject_connection) == OK)
1450 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1451 "from %s (host_reject_connection)", host_and_ident(FALSE));
1452 smtp_printf("554 SMTP service not available\r\n");
1456 /* Test with TCP Wrappers if so configured */
1458 #ifdef USE_TCP_WRAPPERS
1459 if (!hosts_ctl("exim",
1460 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1461 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1462 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1464 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1465 log_write(L_connection_reject,
1466 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1467 "(tcp wrappers)", host_and_ident(FALSE));
1468 smtp_printf("554 SMTP service not available\r\n");
1473 /* Check for reserved slots. Note that the count value doesn't include
1474 this process, as it gets upped in the parent process. */
1476 if (smtp_accept_max > 0 &&
1477 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1479 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1481 log_write(L_connection_reject,
1482 LOG_MAIN, "temporarily refused connection from %s: not in "
1483 "reserve list: connected=%d max=%d reserve=%d%s",
1484 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1485 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1486 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1487 "please try again later\r\n", smtp_active_hostname);
1490 reserved_host = TRUE;
1493 /* If a load level above which only messages from reserved hosts are
1494 accepted is set, check the load. For incoming calls via the daemon, the
1495 check is done in the superior process if there are no reserved hosts, to
1496 save a fork. In all cases, the load average will already be available
1497 in a global variable at this point. */
1499 if (smtp_load_reserve >= 0 &&
1500 load_average > smtp_load_reserve &&
1502 verify_check_host(&smtp_reserve_hosts) != OK)
1504 log_write(L_connection_reject,
1505 LOG_MAIN, "temporarily refused connection from %s: not in "
1506 "reserve list and load average = %.2f", host_and_ident(FALSE),
1507 (double)load_average/1000.0);
1508 smtp_printf("421 %s: Too much load; please try again later\r\n",
1509 smtp_active_hostname);
1513 /* Determine whether unqualified senders or recipients are permitted
1514 for this host. Unfortunately, we have to do this every time, in order to
1515 set the flags so that they can be inspected when considering qualifying
1516 addresses in the headers. For a site that permits no qualification, this
1517 won't take long, however. */
1519 allow_unqualified_sender =
1520 verify_check_host(&sender_unqualified_hosts) == OK;
1522 allow_unqualified_recipient =
1523 verify_check_host(&recipient_unqualified_hosts) == OK;
1525 /* Determine whether HELO/EHLO is required for this host. The requirement
1526 can be hard or soft. */
1528 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1530 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1532 /* Determine whether this hosts is permitted to send syntactic junk
1533 after a HELO or EHLO command. */
1535 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1538 /* For batch SMTP input we are now done. */
1540 if (smtp_batched_input) return TRUE;
1542 /* Run the ACL if it exists */
1544 if (acl_smtp_connect != NULL)
1547 uschar *user_msg, *log_msg;
1548 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1552 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1557 /* Output the initial message for a two-way SMTP connection. It may contain
1558 newlines, which then cause a multi-line response to be given. */
1560 s = expand_string(smtp_banner);
1562 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1563 "failed: %s", smtp_banner, expand_string_message);
1565 /* Remove any terminating newlines; might as well remove trailing space too */
1568 while (p > s && isspace(p[-1])) p--;
1571 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1572 is all contained in a single IP packet. The original code wrote out the
1573 greeting using several calls to fprint/fputc, and on busy servers this could
1574 cause it to be split over more than one packet - which caused CC:Mail to fall
1575 over when it got the second part of the greeting after sending its first
1576 command. Sigh. To try to avoid this, build the complete greeting message
1577 first, and output it in one fell swoop. This gives a better chance of it
1578 ending up as a single packet. */
1580 ss = store_get(size);
1584 do /* At least once, in case we have an empty string */
1587 uschar *linebreak = Ustrchr(p, '\n');
1588 if (linebreak == NULL)
1591 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1595 len = linebreak - p;
1596 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1598 ss = string_cat(ss, &size, &ptr, p, len);
1599 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1601 if (linebreak != NULL) p++;
1605 ss[ptr] = 0; /* string_cat leaves room for this */
1607 /* Before we write the banner, check that there is no input pending, unless
1608 this synchronisation check is disabled. */
1610 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1613 struct timeval tzero;
1617 FD_SET(fileno(smtp_in), &fds);
1618 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1621 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1624 if (rc > 150) rc = 150;
1625 smtp_inbuffer[rc] = 0;
1626 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1627 "synchronization error (input sent without waiting for greeting): "
1628 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1629 string_printing(smtp_inbuffer));
1630 smtp_printf("554 SMTP synchronization error\r\n");
1636 /* Now output the banner */
1638 smtp_printf("%s", ss);
1646 /*************************************************
1647 * Handle SMTP syntax and protocol errors *
1648 *************************************************/
1650 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1651 to do so. Then transmit the error response. The return value depends on the
1652 number of syntax and protocol errors in this SMTP session.
1655 type error type, given as a log flag bit
1656 code response code; <= 0 means don't send a response
1657 data data to reflect in the response (can be NULL)
1658 errmess the error message
1660 Returns: -1 limit of syntax/protocol errors NOT exceeded
1661 +1 limit of syntax/protocol errors IS exceeded
1663 These values fit in with the values of the "done" variable in the main
1664 processing loop in smtp_setup_msg(). */
1667 synprot_error(int type, int code, uschar *data, uschar *errmess)
1671 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1672 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1673 string_printing(cmd_buffer), host_and_ident(TRUE), errmess);
1675 if (++synprot_error_count > smtp_max_synprot_errors)
1678 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1679 "syntax or protocol errors (last command was \"%s\")",
1680 host_and_ident(FALSE), cmd_buffer);
1685 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1686 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1688 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1697 /*************************************************
1698 * Log incomplete transactions *
1699 *************************************************/
1701 /* This function is called after a transaction has been aborted by RSET, QUIT,
1702 connection drops or other errors. It logs the envelope information received
1703 so far in order to preserve address verification attempts.
1705 Argument: string to indicate what aborted the transaction
1710 incomplete_transaction_log(uschar *what)
1712 if (sender_address == NULL || /* No transaction in progress */
1713 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1716 /* Build list of recipients for logging */
1718 if (recipients_count > 0)
1721 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1722 for (i = 0; i < recipients_count; i++)
1723 raw_recipients[i] = recipients_list[i].address;
1724 raw_recipients_count = recipients_count;
1727 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1728 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1734 /*************************************************
1735 * Send SMTP response, possibly multiline *
1736 *************************************************/
1738 /* There are, it seems, broken clients out there that cannot handle multiline
1739 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1740 output nothing for non-final calls, and only the first line for anything else.
1744 final FALSE if the last line isn't the final line
1745 msg message text, possibly containing newlines
1751 smtp_respond(int code, BOOL final, uschar *msg)
1753 if (!final && no_multiline_responses) return;
1757 uschar *nl = Ustrchr(msg, '\n');
1760 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1763 else if (nl[1] == 0 || no_multiline_responses)
1765 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1770 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1772 while (isspace(*msg)) msg++;
1780 /*************************************************
1781 * Handle an ACL failure *
1782 *************************************************/
1784 /* This function is called when acl_check() fails. As well as calls from within
1785 this module, it is called from receive.c for an ACL after DATA. It sorts out
1786 logging the incident, and sets up the error response. A message containing
1787 newlines is turned into a multiline SMTP response, but for logging, only the
1790 There's a table of the response codes to use in globals.c, along with the table
1791 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1792 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1793 that the response should be 252 in the disabled state, because there are broken
1794 clients that try VRFY before RCPT. A 5xx response should be given only when the
1795 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1796 given on refusal, and for AUTH, 503.
1799 where where the ACL was called from
1801 user_msg a message that can be included in an SMTP response
1802 log_msg a message for logging
1804 Returns: 0 in most cases
1805 2 if the failure code was FAIL_DROP, in which case the
1806 SMTP connection should be dropped (this value fits with the
1807 "done" variable in smtp_setup_msg() below)
1811 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1813 int code = acl_wherecodes[where];
1814 BOOL drop = rc == FAIL_DROP;
1816 uschar *sender_info = US"";
1818 #ifdef WITH_CONTENT_SCAN
1819 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1821 (where == ACL_WHERE_PREDATA)? US"DATA" :
1822 (where == ACL_WHERE_DATA)? US"after DATA" :
1823 (smtp_command_argument == NULL)?
1824 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
1825 string_sprintf("%s %s", acl_wherenames[where], smtp_command_argument);
1827 if (drop) rc = FAIL;
1829 /* We used to have sender_address here; however, there was a bug that was not
1830 updating sender_address after a rewrite during a verify. When this bug was
1831 fixed, sender_address at this point became the rewritten address. I'm not sure
1832 this is what should be logged, so I've changed to logging the unrewritten
1833 address to retain backward compatibility. */
1835 #ifndef WITH_CONTENT_SCAN
1836 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1838 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1841 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1842 sender_address_unrewritten : sender_address);
1845 /* If there's been a sender verification failure with a specific message, and
1846 we have not sent a response about it yet, do so now, as a preliminary line for
1847 failures, but not defers. However, log it in both cases. */
1849 if (sender_verified_failed != NULL &&
1850 !testflag(sender_verified_failed, af_sverify_told))
1852 setflag(sender_verified_failed, af_sverify_told);
1854 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1855 host_and_ident(TRUE),
1856 ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail",
1857 sender_verified_failed->address,
1858 (sender_verified_failed->message == NULL)? US"" :
1859 string_sprintf(": %s", sender_verified_failed->message));
1861 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1862 smtp_respond(code, FALSE, string_sprintf(
1863 testflag(sender_verified_failed, af_verify_pmfail)?
1864 "Postmaster verification failed while checking <%s>\n%s\n"
1865 "Several RFCs state that you are required to have a postmaster\n"
1866 "mailbox for each mail domain. This host does not accept mail\n"
1867 "from domains whose servers reject the postmaster address."
1869 testflag(sender_verified_failed, af_verify_nsfail)?
1870 "Callback setup failed while verifying <%s>\n%s\n"
1871 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1872 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1873 "RFC requirements, and stops you from receiving standard bounce\n"
1874 "messages. This host does not accept mail from domains whose servers\n"
1877 "Verification failed for <%s>\n%s",
1878 sender_verified_failed->address,
1879 sender_verified_failed->user_message));
1882 /* Sort out text for logging */
1884 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1885 lognl = Ustrchr(log_msg, '\n');
1886 if (lognl != NULL) *lognl = 0;
1888 /* Send permanent failure response to the command, but the code used isn't
1889 always a 5xx one - see comments at the start of this function. If the original
1890 rc was FAIL_DROP we drop the connection and yield 2. */
1892 if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1893 US"Administrative prohibition" : user_msg);
1895 /* Send temporary failure response to the command. Don't give any details,
1896 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1897 verb, and for a header verify when smtp_return_error_details is set.
1899 This conditional logic is all somewhat of a mess because of the odd
1900 interactions between temp_details and return_error_details. One day it should
1901 be re-implemented in a tidier fashion. */
1905 if (acl_temp_details && user_msg != NULL)
1907 if (smtp_return_error_details &&
1908 sender_verified_failed != NULL &&
1909 sender_verified_failed->message != NULL)
1911 smtp_respond(451, FALSE, sender_verified_failed->message);
1913 smtp_respond(451, TRUE, user_msg);
1916 smtp_printf("451 Temporary local problem - please try later\r\n");
1919 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
1920 Otherwise, log why it is closing if required and return 2. */
1922 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1923 host_and_ident(TRUE),
1924 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1926 if (!drop) return 0;
1928 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1929 smtp_get_connection_info());
1936 /*************************************************
1937 * Verify HELO argument *
1938 *************************************************/
1940 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
1941 matched. It is also called from ACL processing if verify = helo is used and
1942 verification was not previously tried (i.e. helo_try_verify_hosts was not
1943 matched). The result of its processing is to set helo_verified and
1944 helo_verify_failed. These variables should both be FALSE for this function to
1947 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
1948 for IPv6 ::ffff: literals.
1951 Returns: TRUE if testing was completed;
1952 FALSE on a temporary failure
1956 smtp_verify_helo(void)
1960 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
1963 if (sender_helo_name == NULL)
1965 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
1968 else if (sender_helo_name[0] == '[')
1970 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
1971 Ustrlen(sender_host_address)) == 0;
1976 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
1977 helo_verified = Ustrncmp(sender_helo_name + 1,
1978 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
1983 { if (helo_verified) debug_printf("matched host address\n"); }
1986 /* Do a reverse lookup if one hasn't already given a positive or negative
1987 response. If that fails, or the name doesn't match, try checking with a forward
1992 if (sender_host_name == NULL && !host_lookup_failed)
1993 yield = host_name_lookup() != DEFER;
1995 /* If a host name is known, check it and all its aliases. */
1997 if (sender_host_name != NULL)
1999 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2003 HDEBUG(D_receive) debug_printf("matched host name\n");
2007 uschar **aliases = sender_host_aliases;
2008 while (*aliases != NULL)
2010 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2011 if (helo_verified) break;
2016 debug_printf("matched alias %s\n", *(--aliases));
2021 /* Final attempt: try a forward lookup of the helo name */
2027 h.name = sender_helo_name;
2031 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2033 rc = host_find_byname(&h, NULL, NULL, TRUE);
2034 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2039 if (Ustrcmp(hh->address, sender_host_address) == 0)
2041 helo_verified = TRUE;
2043 debug_printf("IP address for %s matches calling address\n",
2053 if (!helo_verified) helo_verify_failed = FALSE; /* We've tried ... */
2060 /*************************************************
2061 * Initialize for SMTP incoming message *
2062 *************************************************/
2064 /* This function conducts the initial dialogue at the start of an incoming SMTP
2065 message, and builds a list of recipients. However, if the incoming message
2066 is part of a batch (-bS option) a separate function is called since it would
2067 be messy having tests splattered about all over this function. This function
2068 therefore handles the case where interaction is occurring. The input and output
2069 files are set up in smtp_in and smtp_out.
2071 The global recipients_list is set to point to a vector of recipient_item
2072 blocks, whose number is given by recipients_count. This is extended by the
2073 receive_add_recipient() function. The global variable sender_address is set to
2074 the sender's address. The yield is +1 if a message has been successfully
2075 started, 0 if a QUIT command was encountered or the connection was refused from
2076 the particular host, or -1 if the connection was lost.
2080 Returns: > 0 message successfully started (reached DATA)
2081 = 0 QUIT read or end of file reached or call refused
2086 smtp_setup_msg(void)
2089 BOOL toomany = FALSE;
2090 BOOL discarded = FALSE;
2091 BOOL last_was_rej_mail = FALSE;
2092 BOOL last_was_rcpt = FALSE;
2093 void *reset_point = store_get(0);
2095 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2097 /* Reset for start of new message. We allow one RSET not to be counted as a
2098 nonmail command, for those MTAs that insist on sending it between every
2099 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2100 TLS between messages (an Exim client may do this if it has messages queued up
2101 for the host). Note: we do NOT reset AUTH at this point. */
2103 smtp_reset(reset_point);
2104 message_ended = END_NOTSTARTED;
2106 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2107 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2108 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2110 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2113 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2115 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2117 /* Batched SMTP is handled in a different function. */
2119 if (smtp_batched_input) return smtp_setup_batch_msg();
2121 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2122 value. The values are 2 larger than the required yield of the function. */
2127 uschar *etrn_command;
2128 uschar *etrn_serialize_key;
2130 uschar *user_msg, *log_msg;
2131 uschar *recipient = NULL;
2132 uschar *hello = NULL;
2133 uschar *set_id = NULL;
2135 BOOL was_rej_mail = FALSE;
2136 BOOL was_rcpt = FALSE;
2137 void (*oldsignal)(int);
2139 int start, end, sender_domain, recipient_domain;
2144 switch(smtp_read_command(TRUE))
2146 /* The AUTH command is not permitted to occur inside a transaction, and may
2147 occur successfully only once per connection, and then only when we've
2148 advertised it. Actually, that isn't quite true. When TLS is started, all
2149 previous information about a connection must be discarded, so a new AUTH is
2150 permitted at that time.
2152 AUTH is initially labelled as a "nonmail command" so that one occurrence
2153 doesn't get counted. We change the label here so that multiple failing
2154 AUTHS will eventually hit the nonmail threshold. */
2157 authentication_failed = TRUE;
2158 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2160 if (!auth_advertised)
2162 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2163 US"AUTH command used when not advertised");
2166 if (sender_host_authenticated != NULL)
2168 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2169 US"already authenticated");
2172 if (sender_address != NULL)
2174 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2175 US"not permitted in mail transaction");
2181 if (acl_smtp_auth != NULL)
2183 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2186 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2191 /* Find the name of the requested authentication mechanism. */
2193 s = smtp_command_argument;
2194 while ((c = *smtp_command_argument) != 0 && !isspace(c))
2196 if (!isalnum(c) && c != '-' && c != '_')
2198 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2199 US"invalid character in authentication mechanism name");
2202 smtp_command_argument++;
2205 /* If not at the end of the line, we must be at white space. Terminate the
2206 name and move the pointer on to any data that may be present. */
2208 if (*smtp_command_argument != 0)
2210 *smtp_command_argument++ = 0;
2211 while (isspace(*smtp_command_argument)) smtp_command_argument++;
2214 /* Search for an authentication mechanism which is configured for use
2215 as a server and which has been advertised. */
2217 for (au = auths; au != NULL; au = au->next)
2219 if (strcmpic(s, au->public_name) == 0 && au->server &&
2220 au->advertised) break;
2225 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2226 string_sprintf("%s authentication mechanism not supported", s));
2230 /* Run the checking code, passing the remainder of the command
2231 line as data. Initialize $0 empty. The authenticator may set up
2232 other numeric variables. Afterwards, have a go at expanding the set_id
2233 string, even if authentication failed - for bad passwords it can be useful
2234 to log the userid. On success, require set_id to expand and exist, and
2235 put it in authenticated_id. Save this in permanent store, as the working
2236 store gets reset at HELO, RSET, etc. */
2239 expand_nlength[0] = 0; /* $0 contains nothing */
2241 c = (au->info->servercode)(au, smtp_command_argument);
2242 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2243 expand_nmax = -1; /* Reset numeric variables */
2245 /* The value of authenticated_id is stored in the spool file and printed in
2246 log lines. It must not contain binary zeros or newline characters. In
2247 normal use, it never will, but when playing around or testing, this error
2248 can (did) happen. To guard against this, ensure that the id contains only
2249 printing characters. */
2251 if (set_id != NULL) set_id = string_printing(set_id);
2253 /* For the non-OK cases, set up additional logging data if set_id
2258 if (set_id != NULL && *set_id != 0)
2259 set_id = string_sprintf(" (set_id=%s)", set_id);
2263 /* Switch on the result */
2268 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2270 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2271 sender_host_authenticated = au->name;
2272 authentication_failed = FALSE;
2274 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2275 ((sender_host_address != NULL)? pnlocal : 0);
2276 s = ss = US"235 Authentication succeeded";
2277 authenticated_by = au;
2281 /* Authentication succeeded, but we failed to expand the set_id string.
2282 Treat this as a temporary error. */
2284 auth_defer_msg = expand_string_message;
2288 s = string_sprintf("435 Unable to authenticate at present%s",
2289 auth_defer_user_msg);
2290 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2291 set_id, auth_defer_msg);
2295 s = ss = US"501 Invalid base64 data";
2299 s = ss = US"501 Authentication cancelled";
2303 s = ss = US"553 Initial data not expected";
2307 s = US"535 Incorrect authentication data";
2308 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2312 s = US"435 Internal error";
2313 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2314 "check", set_id, c);
2318 smtp_printf("%s\r\n", s);
2320 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2321 au->name, host_and_ident(FALSE), ss);
2323 break; /* AUTH_CMD */
2325 /* The HELO/EHLO commands are permitted to appear in the middle of a
2326 session as well as at the beginning. They have the effect of a reset in
2327 addition to their other functions. Their absence at the start cannot be
2328 taken to be an error.
2332 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2333 or 502 failure replies MUST be returned as appropriate. The SMTP
2334 server MUST stay in the same state after transmitting these replies
2335 that it was in before the EHLO was received.
2337 Therefore, we do not do the reset until after checking the command for
2338 acceptability. This change was made for Exim release 4.11. Previously
2339 it did the reset first. */
2350 HELO_EHLO: /* Common code for HELO and EHLO */
2351 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2352 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2354 /* Reject the HELO if its argument was invalid or non-existent. A
2355 successful check causes the argument to be saved in malloc store. */
2357 if (!check_helo(smtp_command_argument))
2359 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2361 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2362 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2363 (*smtp_command_argument == 0)? US"(no argument given)" :
2364 string_printing(smtp_command_argument));
2366 if (++synprot_error_count > smtp_max_synprot_errors)
2368 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2369 "syntax or protocol errors (last command was \"%s\")",
2370 host_and_ident(FALSE), cmd_buffer);
2377 /* If sender_host_unknown is true, we have got here via the -bs interface,
2378 not called from inetd. Otherwise, we are running an IP connection and the
2379 host address will be set. If the helo name is the primary name of this
2380 host and we haven't done a reverse lookup, force one now. If helo_required
2381 is set, ensure that the HELO name matches the actual host. If helo_verify
2382 is set, do the same check, but softly. */
2384 if (!sender_host_unknown)
2386 BOOL old_helo_verified = helo_verified;
2387 uschar *p = smtp_command_argument;
2389 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2392 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2393 because otherwise the log can be confusing. */
2395 if (sender_host_name == NULL &&
2396 (deliver_domain = sender_helo_name, /* set $domain */
2397 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2398 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2399 (void)host_name_lookup();
2401 /* Rebuild the fullhost info to include the HELO name (and the real name
2402 if it was looked up.) */
2404 host_build_sender_fullhost(); /* Rebuild */
2405 set_process_info("handling%s incoming connection from %s",
2406 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2408 /* Verify if configured. This doesn't give much security, but it does
2409 make some people happy to be able to do it. If helo_required is set,
2410 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2411 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2412 now obsolescent, since the verification can now be requested selectively
2415 helo_verified = helo_verify_failed = FALSE;
2416 if (helo_required || helo_verify)
2418 BOOL tempfail = !smtp_verify_helo();
2423 smtp_printf("%d %s argument does not match calling host\r\n",
2424 tempfail? 451 : 550, hello);
2425 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2426 tempfail? "temporarily " : "",
2427 hello, sender_helo_name, host_and_ident(FALSE));
2428 helo_verified = old_helo_verified;
2429 break; /* End of HELO/EHLO processing */
2431 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2432 "helo_try_verify_hosts\n", hello);
2437 #ifdef EXPERIMENTAL_SPF
2438 /* set up SPF context */
2439 spf_init(sender_helo_name, sender_host_address);
2442 /* Apply an ACL check if one is defined */
2444 if (acl_smtp_helo != NULL)
2446 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2449 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2450 sender_helo_name = NULL;
2451 host_build_sender_fullhost(); /* Rebuild */
2456 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2457 abandoning any previous message. */
2459 received_protocol = (esmtp?
2461 ((sender_host_authenticated != NULL)? pauthed : 0) +
2462 ((tls_active >= 0)? pcrpted : 0)]
2464 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2466 ((sender_host_address != NULL)? pnlocal : 0);
2468 smtp_reset(reset_point);
2471 /* Generate an OK reply, including the ident if present, and also
2472 the IP address if present. Reflecting back the ident is intended
2473 as a deterrent to mail forgers. For maximum efficiency, and also
2474 because some broken systems expect each response to be in a single
2475 packet, arrange that it is sent in one write(). */
2477 auth_advertised = FALSE;
2478 pipelining_advertised = FALSE;
2480 tls_advertised = FALSE;
2483 s = string_sprintf("250 %s Hello %s%s%s",
2484 smtp_active_hostname,
2485 (sender_ident == NULL)? US"" : sender_ident,
2486 (sender_ident == NULL)? US"" : US" at ",
2487 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2492 if (sender_host_address != NULL)
2494 s = string_cat(s, &size, &ptr, US" [", 2);
2495 s = string_cat(s, &size, &ptr, sender_host_address,
2496 Ustrlen(sender_host_address));
2497 s = string_cat(s, &size, &ptr, US"]", 1);
2500 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2502 /* If we received EHLO, we must create a multiline response which includes
2503 the functions supported. */
2509 /* I'm not entirely happy with this, as an MTA is supposed to check
2510 that it has enough room to accept a message of maximum size before
2511 it sends this. However, there seems little point in not sending it.
2512 The actual size check happens later at MAIL FROM time. By postponing it
2513 till then, VRFY and EXPN can be used after EHLO when space is short. */
2515 if (thismessage_size_limit > 0)
2517 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2518 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2522 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2525 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2526 clean; if it has an 8-bit character in its hand, it just sends it. It
2527 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2528 However, some users want this option simply in order to stop MUAs
2529 mangling messages that contain top-bit-set characters. It is therefore
2530 provided as an option. */
2532 if (accept_8bitmime)
2533 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2535 /* Advertise ETRN if there's an ACL checking whether a host is
2536 permitted to issue it; a check is made when any host actually tries. */
2538 if (acl_smtp_etrn != NULL)
2540 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2543 /* Advertise EXPN if there's an ACL checking whether a host is
2544 permitted to issue it; a check is made when any host actually tries. */
2546 if (acl_smtp_expn != NULL)
2548 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2551 /* Exim is quite happy with pipelining, so let the other end know that
2552 it is safe to use it, unless advertising is disabled. */
2554 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2556 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2557 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2558 pipelining_advertised = TRUE;
2561 /* If any server authentication mechanisms are configured, advertise
2562 them if the current host is in auth_advertise_hosts. The problem with
2563 advertising always is that some clients then require users to
2564 authenticate (and aren't configurable otherwise) even though it may not
2565 be necessary (e.g. if the host is in host_accept_relay).
2567 RFC 2222 states that SASL mechanism names contain only upper case
2568 letters, so output the names in upper case, though we actually recognize
2569 them in either case in the AUTH command. */
2573 if (verify_check_host(&auth_advertise_hosts) == OK)
2577 for (au = auths; au != NULL; au = au->next)
2579 if (au->server && (au->advertise_condition == NULL ||
2580 expand_check_condition(au->advertise_condition, au->name,
2581 US"authenticator")))
2586 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2588 auth_advertised = TRUE;
2591 s = string_cat(s, &size, &ptr, US" ", 1);
2592 s = string_cat(s, &size, &ptr, au->public_name,
2593 Ustrlen(au->public_name));
2594 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2595 au->advertised = TRUE;
2597 else au->advertised = FALSE;
2599 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2603 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2604 if it has been included in the binary, and the host matches
2605 tls_advertise_hosts. We must *not* advertise if we are already in a
2606 secure connection. */
2609 if (tls_active < 0 &&
2610 verify_check_host(&tls_advertise_hosts) != FAIL)
2612 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2613 tls_advertised = TRUE;
2617 /* Finish off the multiline reply with one that is always available. */
2619 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2622 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2628 if (tls_active >= 0) (void)tls_write(s, ptr); else
2631 (void)fwrite(s, 1, ptr, smtp_out);
2632 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2634 break; /* HELO/EHLO */
2637 /* The MAIL command requires an address as an operand. All we do
2638 here is to parse it for syntactic correctness. The form "<>" is
2639 a special case which converts into an empty string. The start/end
2640 pointers in the original are not used further for this address, as
2641 it is the canonical extracted address which is all that is kept. */
2644 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2645 was_rej_mail = TRUE; /* Reset if accepted */
2647 if (helo_required && !helo_seen)
2649 smtp_printf("503 HELO or EHLO required\r\n");
2650 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2651 "HELO/EHLO given", host_and_ident(FALSE));
2655 if (sender_address != NULL)
2657 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2658 US"sender already given");
2662 if (smtp_command_argument[0] == 0)
2664 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2665 US"MAIL must have an address operand");
2669 /* Check to see if the limit for messages per connection would be
2670 exceeded by accepting further messages. */
2672 if (smtp_accept_max_per_connection > 0 &&
2673 smtp_mailcmd_count > smtp_accept_max_per_connection)
2675 smtp_printf("421 too many messages in this connection\r\n");
2676 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2677 "messages in one connection", host_and_ident(TRUE));
2681 /* Reset for start of message - even if this is going to fail, we
2682 obviously need to throw away any previous data. */
2684 smtp_reset(reset_point);
2686 sender_data = recipient_data = NULL;
2688 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2692 uschar *name, *value, *end;
2693 unsigned long int size;
2695 if (!extract_option(&name, &value)) break;
2697 /* Handle SIZE= by reading the value. We don't do the check till later,
2698 in order to be able to log the sender address on failure. */
2700 if (strcmpic(name, US"SIZE") == 0 &&
2701 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2703 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2705 message_size = (int)size;
2708 /* If this session was initiated with EHLO and accept_8bitmime is set,
2709 Exim will have indicated that it supports the BODY=8BITMIME option. In
2710 fact, it does not support this according to the RFCs, in that it does not
2711 take any special action for forwarding messages containing 8-bit
2712 characters. That is why accept_8bitmime is not the default setting, but
2713 some sites want the action that is provided. We recognize both "8BITMIME"
2714 and "7BIT" as body types, but take no action. */
2716 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2717 (strcmpic(value, US"8BITMIME") == 0 ||
2718 strcmpic(value, US"7BIT") == 0)) {}
2720 /* Handle the AUTH extension. If the value given is not "<>" and either
2721 the ACL says "yes" or there is no ACL but the sending host is
2722 authenticated, we set it up as the authenticated sender. However, if the
2723 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2724 the condition is met. The value of AUTH is an xtext, which means that +,
2725 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2728 else if (strcmpic(name, US"AUTH") == 0)
2730 if (Ustrcmp(value, "<>") != 0)
2735 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2737 /* Put back terminator overrides for error message */
2740 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2741 US"invalid data for AUTH");
2745 if (acl_smtp_mailauth == NULL)
2747 ignore_msg = US"client not authenticated";
2748 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2752 ignore_msg = US"rejected by ACL";
2753 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2754 &user_msg, &log_msg);
2760 if (authenticated_by == NULL ||
2761 authenticated_by->mail_auth_condition == NULL ||
2762 expand_check_condition(authenticated_by->mail_auth_condition,
2763 authenticated_by->name, US"authenticator"))
2764 break; /* Accept the AUTH */
2766 ignore_msg = US"server_mail_auth_condition failed";
2767 if (authenticated_id != NULL)
2768 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2769 ignore_msg, authenticated_id);
2774 authenticated_sender = NULL;
2775 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2776 value, host_and_ident(TRUE), ignore_msg);
2779 /* Should only get DEFER or ERROR here. Put back terminator
2780 overrides for error message */
2785 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2792 /* Unknown option. Stick back the terminator characters and break
2793 the loop. An error for a malformed address will occur. */
2803 /* If we have passed the threshold for rate limiting, apply the current
2804 delay, and update it for next time, provided this is a limited host. */
2806 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2807 verify_check_host(&smtp_ratelimit_hosts) == OK)
2809 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2810 smtp_delay_mail/1000.0);
2811 millisleep((int)smtp_delay_mail);
2812 smtp_delay_mail *= smtp_rlm_factor;
2813 if (smtp_delay_mail > (double)smtp_rlm_limit)
2814 smtp_delay_mail = (double)smtp_rlm_limit;
2817 /* Now extract the address, first applying any SMTP-time rewriting. The
2818 TRUE flag allows "<>" as a sender address. */
2820 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2821 rewrite_one(smtp_command_argument, rewrite_smtp, NULL, FALSE, US"",
2822 global_rewrite_rules) : smtp_command_argument;
2824 /* rfc821_domains = TRUE; << no longer needed */
2826 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2828 /* rfc821_domains = FALSE; << no longer needed */
2830 if (raw_sender == NULL)
2832 done = synprot_error(L_smtp_syntax_error, 501, smtp_command_argument, errmess);
2836 sender_address = raw_sender;
2838 /* If there is a configured size limit for mail, check that this message
2839 doesn't exceed it. The check is postponed to this point so that the sender
2842 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2844 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2845 log_write(L_size_reject,
2846 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2847 "message too big: size%s=%d max=%d",
2849 host_and_ident(TRUE),
2850 (message_size == INT_MAX)? ">" : "",
2852 thismessage_size_limit);
2853 sender_address = NULL;
2857 /* Check there is enough space on the disk unless configured not to.
2858 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2859 plus the current message - i.e. we accept the message only if it won't
2860 reduce the space below the threshold. Add 5000 to the size to allow for
2861 overheads such as the Received: line and storing of recipients, etc.
2862 By putting the check here, even when SIZE is not given, it allow VRFY
2863 and EXPN etc. to be used when space is short. */
2865 if (!receive_check_fs(
2866 (smtp_check_spool_space && message_size >= 0)?
2867 message_size + 5000 : 0))
2869 smtp_printf("452 Space shortage, please try later\r\n");
2870 sender_address = NULL;
2874 /* If sender_address is unqualified, reject it, unless this is a locally
2875 generated message, or the sending host or net is permitted to send
2876 unqualified addresses - typically local machines behaving as MUAs -
2877 in which case just qualify the address. The flag is set above at the start
2878 of the SMTP connection. */
2880 if (sender_domain == 0 && sender_address[0] != 0)
2882 if (allow_unqualified_sender)
2884 sender_domain = Ustrlen(sender_address) + 1;
2885 sender_address = rewrite_address_qualify(sender_address, FALSE);
2886 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2891 smtp_printf("501 %s: sender address must contain a domain\r\n",
2892 smtp_command_argument);
2893 log_write(L_smtp_syntax_error,
2894 LOG_MAIN|LOG_REJECT,
2895 "unqualified sender rejected: <%s> %s%s",
2897 host_and_ident(TRUE),
2899 sender_address = NULL;
2904 /* Apply an ACL check if one is defined, before responding */
2906 rc = (acl_smtp_mail == NULL)? OK :
2907 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2909 if (rc == OK || rc == DISCARD)
2911 smtp_printf("250 OK\r\n");
2912 smtp_delay_rcpt = smtp_rlr_base;
2913 recipients_discarded = (rc == DISCARD);
2914 was_rej_mail = FALSE;
2919 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2920 sender_address = NULL;
2925 /* The RCPT command requires an address as an operand. All we do
2926 here is to parse it for syntactic correctness. There may be any number
2927 of RCPT commands, specifying multiple senders. We build them all into
2928 a data structure that is in argc/argv format. The start/end values
2929 given by parse_extract_address are not used, as we keep only the
2930 extracted address. */
2936 /* There must be a sender address; if the sender was rejected and
2937 pipelining was advertised, we assume the client was pipelining, and do not
2938 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2939 get the same treatment. */
2941 if (sender_address == NULL)
2943 if (pipelining_advertised && last_was_rej_mail)
2945 smtp_printf("503 sender not yet given\r\n");
2946 was_rej_mail = TRUE;
2950 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2951 US"sender not yet given");
2952 was_rcpt = FALSE; /* Not a valid RCPT */
2958 /* Check for an operand */
2960 if (smtp_command_argument[0] == 0)
2962 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2963 US"RCPT must have an address operand");
2968 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2969 as a recipient address */
2971 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2972 rewrite_one(smtp_command_argument, rewrite_smtp, NULL, FALSE, US"",
2973 global_rewrite_rules) : smtp_command_argument;
2975 /* rfc821_domains = TRUE; << no longer needed */
2976 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2977 &recipient_domain, FALSE);
2978 /* rfc821_domains = FALSE; << no longer needed */
2980 if (recipient == NULL)
2982 done = synprot_error(L_smtp_syntax_error, 501, smtp_command_argument, errmess);
2987 /* If the recipient address is unqualified, reject it, unless this is a
2988 locally generated message. However, unqualified addresses are permitted
2989 from a configured list of hosts and nets - typically when behaving as
2990 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2991 really. The flag is set at the start of the SMTP connection.
2993 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2994 assumed this meant "reserved local part", but the revision of RFC 821 and
2995 friends now makes it absolutely clear that it means *mailbox*. Consequently
2996 we must always qualify this address, regardless. */
2998 if (recipient_domain == 0)
3000 if (allow_unqualified_recipient ||
3001 strcmpic(recipient, US"postmaster") == 0)
3003 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3005 recipient_domain = Ustrlen(recipient) + 1;
3006 recipient = rewrite_address_qualify(recipient, TRUE);
3011 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3012 smtp_command_argument);
3013 log_write(L_smtp_syntax_error,
3014 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3015 "<%s> %s%s", recipient, host_and_ident(TRUE),
3021 /* Check maximum allowed */
3023 if (rcpt_count > recipients_max && recipients_max > 0)
3025 if (recipients_max_reject)
3028 smtp_printf("552 too many recipients\r\n");
3030 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3031 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3036 smtp_printf("452 too many recipients\r\n");
3038 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3039 "temporarily rejected: sender=<%s> %s", sender_address,
3040 host_and_ident(TRUE));
3047 /* If we have passed the threshold for rate limiting, apply the current
3048 delay, and update it for next time, provided this is a limited host. */
3050 if (rcpt_count > smtp_rlr_threshold &&
3051 verify_check_host(&smtp_ratelimit_hosts) == OK)
3053 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3054 smtp_delay_rcpt/1000.0);
3055 millisleep((int)smtp_delay_rcpt);
3056 smtp_delay_rcpt *= smtp_rlr_factor;
3057 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3058 smtp_delay_rcpt = (double)smtp_rlr_limit;
3061 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3062 for them. Otherwise, check the access control list for this recipient. */
3064 rc = recipients_discarded? DISCARD :
3065 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3067 /* The ACL was happy */
3071 smtp_printf("250 Accepted\r\n");
3072 receive_add_recipient(recipient, -1);
3075 /* The recipient was discarded */
3077 else if (rc == DISCARD)
3079 smtp_printf("250 Accepted\r\n");
3082 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3083 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3084 (sender_address_unrewritten != NULL)?
3085 sender_address_unrewritten : sender_address,
3086 smtp_command_argument, recipients_discarded? "MAIL" : "RCPT",
3087 (log_msg == NULL)? US"" : US": ",
3088 (log_msg == NULL)? US"" : log_msg);
3091 /* Either the ACL failed the address, or it was deferred. */
3095 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3096 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3101 /* The DATA command is legal only if it follows successful MAIL FROM
3102 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3103 not counted as a protocol error if it follows RCPT (which must have been
3104 rejected if there are no recipients.) This function is complete when a
3105 valid DATA command is encountered.
3107 Note concerning the code used: RFC 2821 says this:
3109 - If there was no MAIL, or no RCPT, command, or all such commands
3110 were rejected, the server MAY return a "command out of sequence"
3111 (503) or "no valid recipients" (554) reply in response to the
3114 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3115 because it is the same whether pipelining is in use or not. */
3118 if (!discarded && recipients_count <= 0)
3120 if (pipelining_advertised && last_was_rcpt)
3121 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3123 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3124 US"valid RCPT command must precede DATA");
3128 if (toomany && recipients_max_reject)
3130 sender_address = NULL; /* This will allow a new MAIL without RSET */
3131 sender_address_unrewritten = NULL;
3132 smtp_printf("554 Too many recipients\r\n");
3136 if (acl_smtp_predata == NULL) rc = OK; else
3138 enable_dollar_recipients = TRUE;
3139 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3141 enable_dollar_recipients = FALSE;
3146 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3148 message_ended = END_NOTENDED; /* Indicate in middle of data */
3151 /* Either the ACL failed the address, or it was deferred. */
3154 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3160 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3162 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3168 /* rfc821_domains = TRUE; << no longer needed */
3169 address = parse_extract_address(smtp_command_argument, &errmess, &start, &end,
3170 &recipient_domain, FALSE);
3171 /* rfc821_domains = FALSE; << no longer needed */
3173 if (address == NULL)
3174 s = string_sprintf("501 %s", errmess);
3177 address_item *addr = deliver_make_addr(address, FALSE);
3178 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3179 -1, -1, NULL, NULL, NULL))
3182 s = string_sprintf("250 <%s> is deliverable", address);
3186 s = (addr->message != NULL)?
3187 string_sprintf("451 <%s> %s", address, addr->message) :
3188 string_sprintf("451 Cannot resolve <%s> at this time", address);
3192 s = (addr->message != NULL)?
3193 string_sprintf("550 <%s> %s", address, addr->message) :
3194 string_sprintf("550 <%s> is not deliverable", address);
3195 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3196 smtp_command_argument, host_and_ident(TRUE));
3201 smtp_printf("%s\r\n", s);
3207 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3209 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3212 BOOL save_log_testing_mode = log_testing_mode;
3213 address_test_mode = log_testing_mode = TRUE;
3214 (void) verify_address(deliver_make_addr(smtp_command_argument, FALSE),
3215 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3217 address_test_mode = FALSE;
3218 log_testing_mode = save_log_testing_mode; /* true for -bh */
3226 if (!tls_advertised)
3228 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3229 US"STARTTLS command used when not advertised");
3233 /* Apply an ACL check if one is defined */
3235 if (acl_smtp_starttls != NULL)
3237 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3241 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3246 /* RFC 2487 is not clear on when this command may be sent, though it
3247 does state that all information previously obtained from the client
3248 must be discarded if a TLS session is started. It seems reasonble to
3249 do an implied RSET when STARTTLS is received. */
3251 incomplete_transaction_log(US"STARTTLS");
3252 smtp_reset(reset_point);
3254 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3256 /* Attempt to start up a TLS session, and if successful, discard all
3257 knowledge that was obtained previously. At least, that's what the RFC says,
3258 and that's what happens by default. However, in order to work round YAEB,
3259 there is an option to remember the esmtp state. Sigh.
3261 We must allow for an extra EHLO command and an extra AUTH command after
3262 STARTTLS that don't add to the nonmail command count. */
3264 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3266 if (!tls_remember_esmtp)
3267 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3268 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3269 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3270 if (sender_helo_name != NULL)
3272 store_free(sender_helo_name);
3273 sender_helo_name = NULL;
3274 host_build_sender_fullhost(); /* Rebuild */
3275 set_process_info("handling incoming TLS connection from %s",
3276 host_and_ident(FALSE));
3278 received_protocol = (esmtp?
3279 protocols[pextend + pcrpted +
3280 ((sender_host_authenticated != NULL)? pauthed : 0)]
3282 protocols[pnormal + pcrpted])
3284 ((sender_host_address != NULL)? pnlocal : 0);
3286 sender_host_authenticated = NULL;
3287 authenticated_id = NULL;
3288 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3289 DEBUG(D_tls) debug_printf("TLS active\n");
3290 break; /* Successful STARTTLS */
3293 /* Some local configuration problem was discovered before actually trying
3294 to do a TLS handshake; give a temporary error. */
3296 else if (rc == DEFER)
3298 smtp_printf("454 TLS currently unavailable\r\n");
3302 /* Hard failure. Reject everything except QUIT or closed connection. One
3303 cause for failure is a nested STARTTLS, in which case tls_active remains
3304 set, but we must still reject all incoming commands. */
3306 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3309 switch(smtp_read_command(FALSE))
3312 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3313 smtp_get_connection_info());
3318 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3319 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3320 smtp_get_connection_info());
3325 smtp_printf("554 Security failure\r\n");
3334 /* The ACL for QUIT is provided for gathering statistical information or
3335 similar; it does not affect the response code, but it can supply a custom
3339 incomplete_transaction_log(US"QUIT");
3341 if (acl_smtp_quit != NULL)
3343 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit,&user_msg,&log_msg);
3345 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3348 else user_msg = NULL;
3350 if (user_msg == NULL)
3351 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3353 smtp_printf("221 %s\r\n", user_msg);
3360 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3361 smtp_get_connection_info());
3366 incomplete_transaction_log(US"RSET");
3367 smtp_reset(reset_point);
3369 smtp_printf("250 Reset OK\r\n");
3370 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3375 smtp_printf("250 OK\r\n");
3379 /* Show ETRN/EXPN/VRFY if there's
3380 an ACL for checking hosts; if actually used, a check will be done for
3384 smtp_printf("214-Commands supported:\r\n");
3388 Ustrcat(buffer, " AUTH");
3390 Ustrcat(buffer, " STARTTLS");
3392 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3393 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3394 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3395 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3396 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3397 smtp_printf("214%s\r\n", buffer);
3403 incomplete_transaction_log(US"connection lost");
3404 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3406 /* Don't log by default unless in the middle of a message, as some mailers
3407 just drop the call rather than sending QUIT, and it clutters up the logs.
3410 if (sender_address != NULL || recipients_count > 0)
3411 log_write(L_lost_incoming_connection,
3413 "unexpected %s while reading SMTP command from %s%s",
3414 sender_host_unknown? "EOF" : "disconnection",
3415 host_and_ident(FALSE), smtp_read_error);
3417 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3418 smtp_get_connection_info(), smtp_read_error);
3425 if (sender_address != NULL)
3427 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3428 US"ETRN is not permitted inside a transaction");
3432 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_command_argument,
3433 host_and_ident(FALSE));
3435 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
3438 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3442 /* Compute the serialization key for this command. */
3444 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_command_argument);
3446 /* If a command has been specified for running as a result of ETRN, we
3447 permit any argument to ETRN. If not, only the # standard form is permitted,
3448 since that is strictly the only kind of ETRN that can be implemented
3449 according to the RFC. */
3451 if (smtp_etrn_command != NULL)
3455 etrn_command = smtp_etrn_command;
3456 deliver_domain = smtp_command_argument;
3457 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3458 US"ETRN processing", &error);
3459 deliver_domain = NULL;
3462 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3464 smtp_printf("458 Internal failure\r\n");
3469 /* Else set up to call Exim with the -R option. */
3473 if (*smtp_command_argument++ != '#')
3475 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3476 US"argument must begin with #");
3479 etrn_command = US"exim -R";
3480 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3481 smtp_command_argument);
3484 /* If we are host-testing, don't actually do anything. */
3490 debug_printf("ETRN command is: %s\n", etrn_command);
3491 debug_printf("ETRN command execution skipped\n");
3493 smtp_printf("250 OK\r\n");
3498 /* If ETRN queue runs are to be serialized, check the database to
3499 ensure one isn't already running. */
3501 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3503 smtp_printf("458 Already processing %s\r\n", smtp_command_argument);
3507 /* Fork a child process and run the command. We don't want to have to
3508 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3509 forking. It should be set that way anyway for external incoming SMTP,
3510 but we save and restore to be tidy. If serialization is required, we
3511 actually run the command in yet another process, so we can wait for it
3512 to complete and then remove the serialization lock. */
3514 oldsignal = signal(SIGCHLD, SIG_IGN);
3516 if ((pid = fork()) == 0)
3518 smtp_input = FALSE; /* This process is not associated with the */
3519 (void)fclose(smtp_in); /* SMTP call any more. */
3520 (void)fclose(smtp_out);
3522 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3524 /* If not serializing, do the exec right away. Otherwise, fork down
3525 into another process. */
3527 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3529 DEBUG(D_exec) debug_print_argv(argv);
3530 exim_nullstd(); /* Ensure std{in,out,err} exist */
3531 execv(CS argv[0], (char *const *)argv);
3532 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3533 etrn_command, strerror(errno));
3534 _exit(EXIT_FAILURE); /* paranoia */
3537 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3538 is, we are in the first subprocess, after forking again. All we can do
3539 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3540 complete, before removing the serialization. */
3543 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3544 "failed: %s", strerror(errno));
3548 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3550 (void)wait(&status);
3551 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3555 enq_end(etrn_serialize_key);
3556 _exit(EXIT_SUCCESS);
3559 /* Back in the top level SMTP process. Check that we started a subprocess
3560 and restore the signal state. */
3564 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3566 smtp_printf("458 Unable to fork process\r\n");
3567 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3569 else smtp_printf("250 OK\r\n");
3571 signal(SIGCHLD, oldsignal);
3576 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3577 US"unexpected argument data");
3581 /* This currently happens only for NULLs, but could be extended. */
3584 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3585 US"NULL character(s) present (shown as '?')");
3586 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3591 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3592 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3593 c = smtp_inend - smtp_inptr;
3594 if (c > 150) c = 150;
3596 incomplete_transaction_log(US"sync failure");
3597 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
3598 "(next input sent too soon: pipelining was%s advertised): "
3599 "rejected \"%s\" %s next input=\"%s\"",
3600 pipelining_advertised? "" : " not",
3601 cmd_buffer, host_and_ident(TRUE),
3602 string_printing(smtp_inptr));
3603 smtp_printf("554 SMTP synchronization error\r\n");
3604 done = 1; /* Pretend eof - drops connection */
3608 case TOO_MANY_NONMAIL_CMD:
3609 incomplete_transaction_log(US"too many non-mail commands");
3610 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3611 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
3612 smtp_command_argument - cmd_buffer, cmd_buffer);
3613 smtp_printf("554 Too many nonmail commands\r\n");
3614 done = 1; /* Pretend eof - drops connection */
3619 if (unknown_command_count++ >= smtp_max_unknown_commands)
3621 log_write(L_smtp_syntax_error, LOG_MAIN,
3622 "SMTP syntax error in \"%s\" %s %s",
3623 string_printing(cmd_buffer), host_and_ident(TRUE),
3624 US"unrecognized command");
3625 incomplete_transaction_log(US"unrecognized command");
3626 smtp_printf("500 Too many unrecognized commands\r\n");
3628 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3629 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3633 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3634 US"unrecognized command");
3638 /* This label is used by goto's inside loops that want to break out to
3639 the end of the command-processing loop. */
3642 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3643 last_was_rcpt = was_rcpt; /* protocol error handling */
3647 return done - 2; /* Convert yield values */
3650 /* End of smtp_in.c */