1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.18 2005/05/23 15:28:38 fanf2 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 *smtp_data;
124 static uschar *cmd_buffer;
126 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
127 final fields of all except AUTH are forced TRUE at the start of a new message
128 setup, to allow one of each between messages that is not counted as a nonmail
129 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
130 allow a new EHLO after starting up TLS.
132 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
133 counted. However, the flag is changed when AUTH is received, so that multiple
134 failing AUTHs will eventually hit the limit. After a successful AUTH, another
135 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
136 forced TRUE, to allow for the re-authentication that can happen at that point.
138 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
139 count of non-mail commands and possibly provoke an error. */
141 static smtp_cmd_list cmd_list[] = {
142 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
143 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
144 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
145 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
147 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
150 /* If you change anything above here, also fix the definitions below. */
152 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
153 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
154 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
155 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
156 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
157 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
158 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
159 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
160 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
163 static smtp_cmd_list *cmd_list_end =
164 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
166 #define CMD_LIST_RSET 0
167 #define CMD_LIST_HELO 1
168 #define CMD_LIST_EHLO 2
169 #define CMD_LIST_AUTH 3
170 #define CMD_LIST_STARTTLS 4
172 static uschar *protocols[] = {
173 US"local-smtp", /* HELO */
174 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
175 US"local-esmtp", /* EHLO */
176 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
177 US"local-esmtpa", /* EHLO->AUTH */
178 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
183 #define pcrpted 1 /* added to pextend or pnormal */
184 #define pauthed 2 /* added to pextend */
185 #define pnlocal 6 /* offset to remove "local" */
187 /* When reading SMTP from a remote host, we have to use our own versions of the
188 C input-reading functions, in order to be able to flush the SMTP output only
189 when about to read more data from the socket. This is the only way to get
190 optimal performance when the client is using pipelining. Flushing for every
191 command causes a separate packet and reply packet each time; saving all the
192 responses up (when pipelining) combines them into one packet and one response.
194 For simplicity, these functions are used for *all* SMTP input, not only when
195 receiving over a socket. However, after setting up a secure socket (SSL), input
196 is read via the OpenSSL library, and another set of functions is used instead
199 These functions are set in the receive_getc etc. variables and called with the
200 same interface as the C functions. However, since there can only ever be
201 one incoming SMTP call, we just use a single buffer and flags. There is no need
202 to implement a complicated private FILE-like structure.*/
204 static uschar *smtp_inbuffer;
205 static uschar *smtp_inptr;
206 static uschar *smtp_inend;
207 static int smtp_had_eof;
208 static int smtp_had_error;
211 /*************************************************
212 * SMTP version of getc() *
213 *************************************************/
215 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
216 it flushes the output, and refills the buffer, with a timeout. The signal
217 handler is set appropriately by the calling function. This function is not used
218 after a connection has negotated itself into an TLS/SSL state.
221 Returns: the next character or EOF
227 if (smtp_inptr >= smtp_inend)
231 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
232 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
237 /* Must put the error text in fixed store, because this might be during
238 header reading, where it releases unused store above the header. */
241 smtp_had_error = save_errno;
242 smtp_read_error = string_copy_malloc(
243 string_sprintf(" (error: %s)", strerror(save_errno)));
245 else smtp_had_eof = 1;
248 smtp_inend = smtp_inbuffer + rc;
249 smtp_inptr = smtp_inbuffer;
251 return *smtp_inptr++;
256 /*************************************************
257 * SMTP version of ungetc() *
258 *************************************************/
260 /* Puts a character back in the input buffer. Only ever
266 Returns: the character
272 *(--smtp_inptr) = ch;
279 /*************************************************
280 * SMTP version of feof() *
281 *************************************************/
283 /* Tests for a previous EOF
286 Returns: non-zero if the eof flag is set
298 /*************************************************
299 * SMTP version of ferror() *
300 *************************************************/
302 /* Tests for a previous read error, and returns with errno
303 restored to what it was when the error was detected.
306 Returns: non-zero if the error flag is set
312 errno = smtp_had_error;
313 return smtp_had_error;
319 /*************************************************
320 * Write formatted string to SMTP channel *
321 *************************************************/
323 /* This is a separate function so that we don't have to repeat everything for
324 TLS support or debugging. It is global so that the daemon and the
325 authentication functions can use it. It does not return any error indication,
326 because major problems such as dropped connections won't show up till an output
327 flush for non-TLS connections. The smtp_fflush() function is available for
328 checking that: for convenience, TLS output errors are remembered here so that
329 they are also picked up later by smtp_fflush().
333 ... optional arguments
339 smtp_printf(char *format, ...)
345 va_start(ap, format);
346 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
347 debug_printf("SMTP>> %s", big_buffer);
350 va_start(ap, format);
352 /* If in a TLS session we have to format the string, and then write it using a
358 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
360 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
361 smtp_closedown(US"Unexpected error");
362 exim_exit(EXIT_FAILURE);
364 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
369 /* Otherwise, just use the standard library function. */
371 if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
377 /*************************************************
378 * Flush SMTP out and check for error *
379 *************************************************/
381 /* This function isn't currently used within Exim (it detects errors when it
382 tries to read the next SMTP input), but is available for use in local_scan().
383 For non-TLS connections, it flushes the output and checks for errors. For
384 TLS-connections, it checks for a previously-detected TLS write error.
387 Returns: 0 for no error; -1 after an error
393 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
394 return smtp_write_error;
399 /*************************************************
400 * SMTP command read timeout *
401 *************************************************/
403 /* Signal handler for timing out incoming SMTP commands. This attempts to
406 Argument: signal number (SIGALRM)
411 command_timeout_handler(int sig)
413 sig = sig; /* Keep picky compilers happy */
414 log_write(L_lost_incoming_connection,
415 LOG_MAIN, "SMTP command timeout on%s connection from %s",
416 (tls_active >= 0)? " TLS" : "",
417 host_and_ident(FALSE));
418 if (smtp_batched_input)
419 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
420 smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
421 smtp_active_hostname);
423 exim_exit(EXIT_FAILURE);
428 /*************************************************
430 *************************************************/
432 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
434 Argument: signal number (SIGTERM)
439 command_sigterm_handler(int sig)
441 sig = sig; /* Keep picky compilers happy */
442 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
443 if (smtp_batched_input)
444 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
445 smtp_printf("421 %s: Service not available - closing connection\r\n",
446 smtp_active_hostname);
447 exim_exit(EXIT_FAILURE);
452 /*************************************************
453 * Read one command line *
454 *************************************************/
456 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
457 There are sites that don't do this, and in any case internal SMTP probably
458 should check only for LF. Consequently, we check here for LF only. The line
459 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
460 an unknown command. The command is read into the static cmd_buffer.
462 The character reading routine sets up a timeout for each block actually read
463 from the input (which may contain more than one command). We set up a special
464 signal handler that closes down the session on a timeout. Control does not
468 check_sync if TRUE, check synchronization rules if global option is TRUE
470 Returns: a code identifying the command (enumerated above)
474 smtp_read_command(BOOL check_sync)
479 BOOL hadnull = FALSE;
481 os_non_restarting_signal(SIGALRM, command_timeout_handler);
483 while ((c = (receive_getc)()) != '\n' && c != EOF)
485 if (ptr >= cmd_buffer_size)
487 os_non_restarting_signal(SIGALRM, sigalrm_handler);
495 cmd_buffer[ptr++] = c;
498 receive_linecount++; /* For BSMTP errors */
499 os_non_restarting_signal(SIGALRM, sigalrm_handler);
501 /* If hit end of file, return pseudo EOF command. Whether we have a
502 part-line already read doesn't matter, since this is an error state. */
504 if (c == EOF) return EOF_CMD;
506 /* Remove any CR and white space at the end of the line, and terminate the
509 while (ptr > 0 && isspace(cmd_buffer[ptr-1])) ptr--;
512 DEBUG(D_receive) debug_printf("SMTP<< %s\n", cmd_buffer);
514 /* NULLs are not allowed in SMTP commands */
516 if (hadnull) return BADCHAR_CMD;
518 /* Scan command list and return identity, having set the data pointer
519 to the start of the actual data characters. Check for SMTP synchronization
522 for (p = cmd_list; p < cmd_list_end; p++)
524 if (strncmpic(cmd_buffer, US p->name, p->len) == 0)
526 if (smtp_inptr < smtp_inend && /* Outstanding input */
527 p->cmd < sync_cmd_limit && /* Command should sync */
528 check_sync && /* Local flag set */
529 smtp_enforce_sync && /* Global flag set */
530 sender_host_address != NULL && /* Not local input */
531 !sender_host_notsocket) /* Really is a socket */
534 /* Point after the command, but don't skip over leading spaces till after
535 the following test, so that if it fails, the command name can easily be
538 smtp_data = cmd_buffer + p->len;
540 /* Count non-mail commands from those hosts that are controlled in this
541 way. The default is all hosts. We don't waste effort checking the list
542 until we get a non-mail command, but then cache the result to save checking
543 again. If there's a DEFER while checking the host, assume it's in the list.
545 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
546 start of each incoming message by fiddling with the value in the table. */
550 if (count_nonmail == TRUE_UNSET) count_nonmail =
551 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
552 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
553 return TOO_MANY_NONMAIL_CMD;
556 /* Get the data pointer over leading spaces and return; if there is no data
557 for a command that expects it, we give the error centrally here. */
559 while (isspace(*smtp_data)) smtp_data++;
560 return (p->has_arg || *smtp_data == 0)? p->cmd : BADARG_CMD;
564 /* Enforce synchronization for unknown commands */
566 if (smtp_inptr < smtp_inend && /* Outstanding input */
567 check_sync && /* Local flag set */
568 smtp_enforce_sync && /* Global flag set */
569 sender_host_address != NULL && /* Not local input */
570 !sender_host_notsocket) /* Really is a socket */
578 /*************************************************
579 * Forced closedown of call *
580 *************************************************/
582 /* This function is called from log.c when Exim is dying because of a serious
583 disaster, and also from some other places. If an incoming non-batched SMTP
584 channel is open, it swallows the rest of the incoming message if in the DATA
585 phase, sends the reply string, and gives an error to all subsequent commands
586 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
589 Argument: SMTP reply string to send, excluding the code
594 smtp_closedown(uschar *message)
596 if (smtp_in == NULL || smtp_batched_input) return;
597 receive_swallow_smtp();
598 smtp_printf("421 %s\r\n", message);
602 switch(smtp_read_command(FALSE))
608 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
613 smtp_printf("250 Reset OK\r\n");
617 smtp_printf("421 %s\r\n", message);
626 /*************************************************
627 * Set up connection info for logging *
628 *************************************************/
630 /* This function is called when logging information about an SMTP connection.
631 It sets up appropriate source information, depending on the type of connection.
634 Returns: a string describing the connection
638 smtp_get_connection_info(void)
641 return string_sprintf("SMTP connection from %s", sender_fullhost);
643 if (sender_host_unknown || sender_host_notsocket)
644 return string_sprintf("SMTP connection from %s", sender_ident);
647 return string_sprintf("SMTP connection from %s (via inetd)", sender_fullhost);
649 if ((log_extra_selector & LX_incoming_interface) != 0 &&
650 interface_address != NULL)
651 return string_sprintf("SMTP connection from %s I=[%s]:%d", sender_fullhost,
652 interface_address, interface_port);
654 return string_sprintf("SMTP connection from %s", sender_fullhost);
659 /*************************************************
660 * Check HELO line and set sender_helo_name *
661 *************************************************/
663 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
664 the domain name of the sending host, or an ip literal in square brackets. The
665 arrgument is placed in sender_helo_name, which is in malloc store, because it
666 must persist over multiple incoming messages. If helo_accept_junk is set, this
667 host is permitted to send any old junk (needed for some broken hosts).
668 Otherwise, helo_allow_chars can be used for rogue characters in general
669 (typically people want to let in underscores).
672 s the data portion of the line (already past any white space)
674 Returns: TRUE or FALSE
678 check_helo(uschar *s)
681 uschar *end = s + Ustrlen(s);
682 BOOL yield = helo_accept_junk;
684 /* Discard any previous helo name */
686 if (sender_helo_name != NULL)
688 store_free(sender_helo_name);
689 sender_helo_name = NULL;
692 /* Skip tests if junk is permitted. */
696 /* Allow the new standard form for IPv6 address literals, namely,
697 [IPv6:....], and because someone is bound to use it, allow an equivalent
698 IPv4 form. Allow plain addresses as well. */
705 if (strncmpic(s, US"[IPv6:", 6) == 0)
706 yield = (string_is_ip_address(s+6, NULL) == 6);
707 else if (strncmpic(s, US"[IPv4:", 6) == 0)
708 yield = (string_is_ip_address(s+6, NULL) == 4);
710 yield = (string_is_ip_address(s+1, NULL) != 0);
715 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
716 that have been configured (usually underscore - sigh). */
723 if (!isalnum(*s) && *s != '.' && *s != '-' &&
724 Ustrchr(helo_allow_chars, *s) == NULL)
734 /* Save argument if OK */
736 if (yield) sender_helo_name = string_copy_malloc(start);
744 /*************************************************
745 * Extract SMTP command option *
746 *************************************************/
748 /* This function picks the next option setting off the end of smtp_data. It
749 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
750 things that can appear there.
753 name point this at the name
754 value point this at the data string
756 Returns: TRUE if found an option
760 extract_option(uschar **name, uschar **value)
763 uschar *v = smtp_data + Ustrlen(smtp_data) -1;
764 while (isspace(*v)) v--;
767 while (v > smtp_data && *v != '=' && !isspace(*v)) v--;
768 if (*v != '=') return FALSE;
771 while(isalpha(n[-1])) n--;
773 if (n[-1] != ' ') return FALSE;
788 /*************************************************
789 * Reset for new message *
790 *************************************************/
792 /* This function is called whenever the SMTP session is reset from
793 within either of the setup functions.
795 Argument: the stacking pool storage reset point
800 smtp_reset(void *reset_point)
803 store_reset(reset_point);
804 recipients_list = NULL;
805 rcpt_count = rcpt_defer_count = rcpt_fail_count =
806 raw_recipients_count = recipients_count = recipients_list_max = 0;
807 message_linecount = 0;
809 acl_warn_headers = NULL;
810 queue_only_policy = FALSE;
811 deliver_freeze = FALSE; /* Can be set by ACL */
812 fake_response = OK; /* Can be set by ACL */
813 #ifdef WITH_CONTENT_SCAN
814 no_mbox_unspool = FALSE; /* Can be set by ACL */
816 submission_mode = FALSE; /* Can be set by ACL */
817 active_local_from_check = local_from_check; /* Can be set by ACL */
818 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
819 sender_address = NULL;
820 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
821 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
822 sender_verified_list = NULL; /* No senders verified */
823 memset(sender_address_cache, 0, sizeof(sender_address_cache));
824 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
825 authenticated_sender = NULL;
826 #ifdef EXPERIMENTAL_BRIGHTMAIL
830 #ifdef EXPERIMENTAL_DOMAINKEYS
833 #ifdef EXPERIMENTAL_SPF
834 spf_header_comment = NULL;
837 spf_smtp_comment = NULL;
839 body_linecount = body_zerocount = 0;
841 for (i = 0; i < ACL_M_MAX; i++) acl_var[ACL_C_MAX + i] = NULL;
843 /* The message body variables use malloc store. They may be set if this is
844 not the first message in an SMTP session and the previous message caused them
845 to be referenced in an ACL. */
847 if (message_body != NULL)
849 store_free(message_body);
853 if (message_body_end != NULL)
855 store_free(message_body_end);
856 message_body_end = NULL;
859 /* Warning log messages are also saved in malloc store. They are saved to avoid
860 repetition in the same message, but it seems right to repeat them for different
863 while (acl_warn_logged != NULL)
865 string_item *this = acl_warn_logged;
866 acl_warn_logged = acl_warn_logged->next;
875 /*************************************************
876 * Initialize for incoming batched SMTP message *
877 *************************************************/
879 /* This function is called from smtp_setup_msg() in the case when
880 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
881 of messages in one file with SMTP commands between them. All errors must be
882 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
883 relevant. After an error on a sender, or an invalid recipient, the remainder
884 of the message is skipped. The value of received_protocol is already set.
887 Returns: > 0 message successfully started (reached DATA)
888 = 0 QUIT read or end of file reached
893 smtp_setup_batch_msg(void)
896 void *reset_point = store_get(0);
898 /* Save the line count at the start of each transaction - single commands
899 like HELO and RSET count as whole transactions. */
901 bsmtp_transaction_linecount = receive_linecount;
903 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
905 smtp_reset(reset_point); /* Reset for start of message */
907 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
908 value. The values are 2 larger than the required yield of the function. */
913 uschar *recipient = NULL;
914 int start, end, sender_domain, recipient_domain;
916 switch(smtp_read_command(FALSE))
918 /* The HELO/EHLO commands set sender_address_helo if they have
919 valid data; otherwise they are ignored, except that they do
920 a reset of the state. */
925 check_helo(smtp_data);
929 smtp_reset(reset_point);
930 bsmtp_transaction_linecount = receive_linecount;
934 /* The MAIL FROM command requires an address as an operand. All we
935 do here is to parse it for syntactic correctness. The form "<>" is
936 a special case which converts into an empty string. The start/end
937 pointers in the original are not used further for this address, as
938 it is the canonical extracted address which is all that is kept. */
941 if (sender_address != NULL)
942 /* The function moan_smtp_batch() does not return. */
943 moan_smtp_batch(cmd_buffer, "503 Sender already given");
945 if (smtp_data[0] == 0)
946 /* The function moan_smtp_batch() does not return. */
947 moan_smtp_batch(cmd_buffer, "501 MAIL FROM must have an address operand");
949 /* Reset to start of message */
951 smtp_reset(reset_point);
953 /* Apply SMTP rewrite */
955 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
956 rewrite_one(smtp_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
957 US"", global_rewrite_rules) : smtp_data;
959 /* Extract the address; the TRUE flag allows <> as valid */
962 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
965 if (raw_sender == NULL)
966 /* The function moan_smtp_batch() does not return. */
967 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
969 sender_address = string_copy(raw_sender);
971 /* Qualify unqualified sender addresses if permitted to do so. */
973 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
975 if (allow_unqualified_sender)
977 sender_address = rewrite_address_qualify(sender_address, FALSE);
978 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
979 "and rewritten\n", raw_sender);
981 /* The function moan_smtp_batch() does not return. */
982 else moan_smtp_batch(cmd_buffer, "501 sender address must contain "
988 /* The RCPT TO command requires an address as an operand. All we do
989 here is to parse it for syntactic correctness. There may be any number
990 of RCPT TO commands, specifying multiple senders. We build them all into
991 a data structure that is in argc/argv format. The start/end values
992 given by parse_extract_address are not used, as we keep only the
993 extracted address. */
996 if (sender_address == NULL)
997 /* The function moan_smtp_batch() does not return. */
998 moan_smtp_batch(cmd_buffer, "503 No sender yet given");
1000 if (smtp_data[0] == 0)
1001 /* The function moan_smtp_batch() does not return. */
1002 moan_smtp_batch(cmd_buffer, "501 RCPT TO must have an address operand");
1004 /* Check maximum number allowed */
1006 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1007 /* The function moan_smtp_batch() does not return. */
1008 moan_smtp_batch(cmd_buffer, "%s too many recipients",
1009 recipients_max_reject? "552": "452");
1011 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1012 recipient address */
1014 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1015 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
1016 global_rewrite_rules) : smtp_data;
1018 /* rfc821_domains = TRUE; << no longer needed */
1019 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1020 &recipient_domain, FALSE);
1021 /* rfc821_domains = FALSE; << no longer needed */
1023 if (recipient == NULL)
1024 /* The function moan_smtp_batch() does not return. */
1025 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
1027 /* If the recipient address is unqualified, qualify it if permitted. Then
1028 add it to the list of recipients. */
1030 if (recipient_domain == 0)
1032 if (allow_unqualified_recipient)
1034 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1036 recipient = rewrite_address_qualify(recipient, TRUE);
1038 /* The function moan_smtp_batch() does not return. */
1039 else moan_smtp_batch(cmd_buffer, "501 recipient address must contain "
1042 receive_add_recipient(recipient, -1);
1046 /* The DATA command is legal only if it follows successful MAIL FROM
1047 and RCPT TO commands. This function is complete when a valid DATA
1048 command is encountered. */
1051 if (sender_address == NULL || recipients_count <= 0)
1053 /* The function moan_smtp_batch() does not return. */
1054 if (sender_address == NULL)
1055 moan_smtp_batch(cmd_buffer,
1056 "503 MAIL FROM:<sender> command must precede DATA");
1058 moan_smtp_batch(cmd_buffer,
1059 "503 RCPT TO:<recipient> must precede DATA");
1063 done = 3; /* DATA successfully achieved */
1064 message_ended = END_NOTENDED; /* Indicate in middle of message */
1069 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1076 bsmtp_transaction_linecount = receive_linecount;
1087 /* The function moan_smtp_batch() does not return. */
1088 moan_smtp_batch(cmd_buffer, "501 Unexpected argument data");
1093 /* The function moan_smtp_batch() does not return. */
1094 moan_smtp_batch(cmd_buffer, "501 Unexpected NULL in SMTP command");
1099 /* The function moan_smtp_batch() does not return. */
1100 moan_smtp_batch(cmd_buffer, "500 Command unrecognized");
1105 return done - 2; /* Convert yield values */
1111 /*************************************************
1112 * Start an SMTP session *
1113 *************************************************/
1115 /* This function is called at the start of an SMTP session. Thereafter,
1116 smtp_setup_msg() is called to initiate each separate message. This
1117 function does host-specific testing, and outputs the banner line.
1120 Returns: FALSE if the session can not continue; something has
1121 gone wrong, or the connection to the host is blocked
1125 smtp_start_session(void)
1131 /* If we are running in the test harness, and the incoming call is from
1132 127.0.0.2 (sic), have a short delay. This makes it possible to test handling of
1133 input sent too soon (before the banner is output). */
1135 if (running_in_test_harness &&
1136 sender_host_address != NULL &&
1137 Ustrcmp(sender_host_address, "127.0.0.2") == 0)
1140 /* Default values for certain variables */
1142 helo_seen = esmtp = helo_accept_junk = FALSE;
1143 count_nonmail = TRUE_UNSET;
1144 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1145 smtp_delay_mail = smtp_rlm_base;
1146 auth_advertised = FALSE;
1147 pipelining_advertised = FALSE;
1148 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1150 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1152 sender_host_authenticated = NULL;
1153 authenticated_by = NULL;
1156 tls_cipher = tls_peerdn = NULL;
1157 tls_advertised = FALSE;
1160 /* Reset ACL connection variables */
1162 for (i = 0; i < ACL_C_MAX; i++) acl_var[i] = NULL;
1164 cmd_buffer = (uschar *)malloc(cmd_buffer_size + 1); /* allow for trailing 0 */
1165 if (cmd_buffer == NULL)
1166 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1167 "malloc() failed for SMTP command buffer");
1169 /* For batched input, the protocol setting can be overridden from the
1170 command line by a trusted caller. */
1172 if (smtp_batched_input)
1174 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1177 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1178 reset later if any of EHLO/AUTH/STARTTLS are received. */
1182 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1184 /* Set up the buffer for inputting using direct read() calls, and arrange to
1185 call the local functions instead of the standard C ones. */
1187 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1188 if (smtp_inbuffer == NULL)
1189 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1190 receive_getc = smtp_getc;
1191 receive_ungetc = smtp_ungetc;
1192 receive_feof = smtp_feof;
1193 receive_ferror = smtp_ferror;
1194 smtp_inptr = smtp_inend = smtp_inbuffer;
1195 smtp_had_eof = smtp_had_error = 0;
1197 /* Set up the message size limit; this may be host-specific */
1199 thismessage_size_limit = expand_string_integer(message_size_limit);
1200 if (thismessage_size_limit < 0)
1202 if (thismessage_size_limit == -1)
1203 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1204 "%s", expand_string_message);
1206 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1207 "%s", expand_string_message);
1208 smtp_closedown(US"Temporary local problem - please try later");
1212 /* When a message is input locally via the -bs or -bS options, sender_host_
1213 unknown is set unless -oMa was used to force an IP address, in which case it
1214 is checked like a real remote connection. When -bs is used from inetd, this
1215 flag is not set, causing the sending host to be checked. The code that deals
1216 with IP source routing (if configured) is never required for -bs or -bS and
1217 the flag sender_host_notsocket is used to suppress it.
1219 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1220 reserve for certain hosts and/or networks. */
1222 if (!sender_host_unknown)
1225 BOOL reserved_host = FALSE;
1227 /* Look up IP options (source routing info) on the socket if this is not an
1228 -oMa "host", and if any are found, log them and drop the connection.
1230 Linux (and others now, see below) is different to everyone else, so there
1231 has to be some conditional compilation here. Versions of Linux before 2.1.15
1232 used a structure whose name was "options". Somebody finally realized that
1233 this name was silly, and it got changed to "ip_options". I use the
1234 newer name here, but there is a fudge in the script that sets up os.h
1235 to define a macro in older Linux systems.
1237 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1238 glibc 2, which has chosen ip_opts for the structure name. This is now
1239 really a glibc thing rather than a Linux thing, so the condition name
1240 has been changed to reflect this. It is relevant also to GNU/Hurd.
1242 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1243 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1244 a special macro defined in the os.h file.
1246 Some DGUX versions on older hardware appear not to support IP options at
1247 all, so there is now a general macro which can be set to cut out this
1250 How to do this properly in IPv6 is not yet known. */
1252 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1254 #ifdef GLIBC_IP_OPTIONS
1255 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1260 #elif defined DARWIN_IP_OPTIONS
1266 if (!host_checking && !sender_host_notsocket)
1269 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1270 struct ip_options *ipopt = store_get(optlen);
1272 struct ip_opts ipoptblock;
1273 struct ip_opts *ipopt = &ipoptblock;
1274 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1276 struct ipoption ipoptblock;
1277 struct ipoption *ipopt = &ipoptblock;
1278 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1281 /* Occasional genuine failures of getsockopt() have been seen - for
1282 example, "reset by peer". Therefore, just log and give up on this
1283 call, unless the error is ENOPROTOOPT. This error is given by systems
1284 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1285 of writing. So for that error, carry on - we just can't do an IP options
1288 DEBUG(D_receive) debug_printf("checking for IP options\n");
1290 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1293 if (errno != ENOPROTOOPT)
1295 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1296 host_and_ident(FALSE), strerror(errno));
1297 smtp_printf("451 SMTP service not available\r\n");
1302 /* Deal with any IP options that are set. On the systems I have looked at,
1303 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1304 more logging data than will fit in big_buffer. Nevertheless, after somebody
1305 questioned this code, I've added in some paranoid checking. */
1307 else if (optlen > 0)
1309 uschar *p = big_buffer;
1310 uschar *pend = big_buffer + big_buffer_size;
1311 uschar *opt, *adptr;
1313 struct in_addr addr;
1316 uschar *optstart = (uschar *)(ipopt->__data);
1318 uschar *optstart = (uschar *)(ipopt->ip_opts);
1320 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1323 DEBUG(D_receive) debug_printf("IP options exist\n");
1325 Ustrcpy(p, "IP options on incoming call:");
1328 for (opt = optstart; opt != NULL &&
1329 opt < (uschar *)(ipopt) + optlen;)
1343 if (!string_format(p, pend-p, " %s [@%s",
1344 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1346 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1348 inet_ntoa(ipopt->ip_dst)))
1350 inet_ntoa(ipopt->ipopt_dst)))
1358 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1360 while (optcount-- > 0)
1362 memcpy(&addr, adptr, sizeof(addr));
1363 if (!string_format(p, pend - p - 1, "%s%s",
1364 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1370 adptr += sizeof(struct in_addr);
1379 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1382 for (i = 0; i < opt[1]; i++)
1384 sprintf(CS p, "%2.2x ", opt[i]);
1395 log_write(0, LOG_MAIN, "%s", big_buffer);
1397 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1399 log_write(0, LOG_MAIN|LOG_REJECT,
1400 "connection from %s refused (IP options)", host_and_ident(FALSE));
1402 smtp_printf("554 SMTP service not available\r\n");
1406 /* Length of options = 0 => there are no options */
1408 else DEBUG(D_receive) debug_printf("no IP options found\n");
1410 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1412 /* Set keep-alive in socket options. The option is on by default. This
1413 setting is an attempt to get rid of some hanging connections that stick in
1414 read() when the remote end (usually a dialup) goes away. */
1416 if (smtp_accept_keepalive && !sender_host_notsocket)
1417 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1419 /* If the current host matches host_lookup, set the name by doing a
1420 reverse lookup. On failure, sender_host_name will be NULL and
1421 host_lookup_failed will be TRUE. This may or may not be serious - optional
1424 if (verify_check_host(&host_lookup) == OK)
1426 (void)host_name_lookup();
1427 host_build_sender_fullhost();
1430 /* Delay this until we have the full name, if it is looked up. */
1432 set_process_info("handling incoming connection from %s",
1433 host_and_ident(FALSE));
1435 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1436 smtps port for use with older style SSL MTAs. */
1439 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1443 /* Test for explicit connection rejection */
1445 if (verify_check_host(&host_reject_connection) == OK)
1447 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1448 "from %s (host_reject_connection)", host_and_ident(FALSE));
1449 smtp_printf("554 SMTP service not available\r\n");
1453 /* Test with TCP Wrappers if so configured */
1455 #ifdef USE_TCP_WRAPPERS
1456 if (!hosts_ctl("exim",
1457 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1458 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1459 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1461 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1462 log_write(L_connection_reject,
1463 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1464 "(tcp wrappers)", host_and_ident(FALSE));
1465 smtp_printf("554 SMTP service not available\r\n");
1470 /* Check for reserved slots. Note that the count value doesn't include
1471 this process, as it gets upped in the parent process. */
1473 if (smtp_accept_max > 0 &&
1474 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1476 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1478 log_write(L_connection_reject,
1479 LOG_MAIN, "temporarily refused connection from %s: not in "
1480 "reserve list: connected=%d max=%d reserve=%d%s",
1481 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1482 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1483 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1484 "please try again later\r\n", smtp_active_hostname);
1487 reserved_host = TRUE;
1490 /* If a load level above which only messages from reserved hosts are
1491 accepted is set, check the load. For incoming calls via the daemon, the
1492 check is done in the superior process if there are no reserved hosts, to
1493 save a fork. In all cases, the load average will already be available
1494 in a global variable at this point. */
1496 if (smtp_load_reserve >= 0 &&
1497 load_average > smtp_load_reserve &&
1499 verify_check_host(&smtp_reserve_hosts) != OK)
1501 log_write(L_connection_reject,
1502 LOG_MAIN, "temporarily refused connection from %s: not in "
1503 "reserve list and load average = %.2f", host_and_ident(FALSE),
1504 (double)load_average/1000.0);
1505 smtp_printf("421 %s: Too much load; please try again later\r\n",
1506 smtp_active_hostname);
1510 /* Determine whether unqualified senders or recipients are permitted
1511 for this host. Unfortunately, we have to do this every time, in order to
1512 set the flags so that they can be inspected when considering qualifying
1513 addresses in the headers. For a site that permits no qualification, this
1514 won't take long, however. */
1516 allow_unqualified_sender =
1517 verify_check_host(&sender_unqualified_hosts) == OK;
1519 allow_unqualified_recipient =
1520 verify_check_host(&recipient_unqualified_hosts) == OK;
1522 /* Determine whether HELO/EHLO is required for this host. The requirement
1523 can be hard or soft. */
1525 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1527 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1529 /* Determine whether this hosts is permitted to send syntactic junk
1530 after a HELO or EHLO command. */
1532 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1535 /* For batch SMTP input we are now done. */
1537 if (smtp_batched_input) return TRUE;
1539 /* Run the ACL if it exists */
1541 if (acl_smtp_connect != NULL)
1544 uschar *user_msg, *log_msg;
1545 smtp_data = US"in \"connect\" ACL"; /* For logged failure message */
1546 rc = acl_check(ACL_WHERE_CONNECT, US"", acl_smtp_connect, &user_msg,
1550 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1555 /* Output the initial message for a two-way SMTP connection. It may contain
1556 newlines, which then cause a multi-line response to be given. */
1558 s = expand_string(smtp_banner);
1560 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1561 "failed: %s", smtp_banner, expand_string_message);
1563 /* Remove any terminating newlines; might as well remove trailing space too */
1566 while (p > s && isspace(p[-1])) p--;
1569 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1570 is all contained in a single IP packet. The original code wrote out the
1571 greeting using several calls to fprint/fputc, and on busy servers this could
1572 cause it to be split over more than one packet - which caused CC:Mail to fall
1573 over when it got the second part of the greeting after sending its first
1574 command. Sigh. To try to avoid this, build the complete greeting message
1575 first, and output it in one fell swoop. This gives a better chance of it
1576 ending up as a single packet. */
1578 ss = store_get(size);
1582 do /* At least once, in case we have an empty string */
1585 uschar *linebreak = Ustrchr(p, '\n');
1586 if (linebreak == NULL)
1589 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1593 len = linebreak - p;
1594 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1596 ss = string_cat(ss, &size, &ptr, p, len);
1597 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1599 if (linebreak != NULL) p++;
1603 ss[ptr] = 0; /* string_cat leaves room for this */
1605 /* Before we write the banner, check that there is no input pending, unless
1606 this synchronisation check is disabled. */
1608 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1611 struct timeval tzero;
1615 FD_SET(fileno(smtp_in), &fds);
1616 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1619 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1622 if (rc > 150) rc = 150;
1623 smtp_inbuffer[rc] = 0;
1624 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: "
1625 "synchronization error (input sent without waiting for greeting): "
1626 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1627 string_printing(smtp_inbuffer));
1628 smtp_printf("554 SMTP synchronization error\r\n");
1634 /* Now output the banner */
1636 smtp_printf("%s", ss);
1644 /*************************************************
1645 * Handle SMTP syntax and protocol errors *
1646 *************************************************/
1648 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1649 to do so. Then transmit the error response. The return value depends on the
1650 number of syntax and protocol errors in this SMTP session.
1653 type error type, given as a log flag bit
1654 code response code; <= 0 means don't send a response
1655 data data to reflect in the response (can be NULL)
1656 errmess the error message
1658 Returns: -1 limit of syntax/protocol errors NOT exceeded
1659 +1 limit of syntax/protocol errors IS exceeded
1661 These values fit in with the values of the "done" variable in the main
1662 processing loop in smtp_setup_msg(). */
1665 synprot_error(int type, int code, uschar *data, uschar *errmess)
1669 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1670 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1671 string_printing(cmd_buffer), host_and_ident(TRUE), errmess);
1673 if (++synprot_error_count > smtp_max_synprot_errors)
1676 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1677 "syntax or protocol errors (last command was \"%s\")",
1678 host_and_ident(FALSE), cmd_buffer);
1683 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1684 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1686 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1695 /*************************************************
1696 * Log incomplete transactions *
1697 *************************************************/
1699 /* This function is called after a transaction has been aborted by RSET, QUIT,
1700 connection drops or other errors. It logs the envelope information received
1701 so far in order to preserve address verification attempts.
1703 Argument: string to indicate what aborted the transaction
1708 incomplete_transaction_log(uschar *what)
1710 if (sender_address == NULL || /* No transaction in progress */
1711 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1714 /* Build list of recipients for logging */
1716 if (recipients_count > 0)
1719 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1720 for (i = 0; i < recipients_count; i++)
1721 raw_recipients[i] = recipients_list[i].address;
1722 raw_recipients_count = recipients_count;
1725 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1726 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1732 /*************************************************
1733 * Send SMTP response, possibly multiline *
1734 *************************************************/
1736 /* There are, it seems, broken clients out there that cannot handle multiline
1737 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1738 output nothing for non-final calls, and only the first line for anything else.
1742 final FALSE if the last line isn't the final line
1743 msg message text, possibly containing newlines
1749 smtp_respond(int code, BOOL final, uschar *msg)
1751 if (!final && no_multiline_responses) return;
1755 uschar *nl = Ustrchr(msg, '\n');
1758 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1761 else if (nl[1] == 0 || no_multiline_responses)
1763 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1768 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1770 while (isspace(*msg)) msg++;
1778 /*************************************************
1779 * Handle an ACL failure *
1780 *************************************************/
1782 /* This function is called when acl_check() fails. As well as calls from within
1783 this module, it is called from receive.c for an ACL after DATA. It sorts out
1784 logging the incident, and sets up the error response. A message containing
1785 newlines is turned into a multiline SMTP response, but for logging, only the
1788 There's a table of the response codes to use in globals.c, along with the table
1789 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1790 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1791 that the response should be 252 in the disabled state, because there are broken
1792 clients that try VRFY before RCPT. A 5xx response should be given only when the
1793 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1794 given on refusal, and for AUTH, 503.
1797 where where the ACL was called from
1799 user_msg a message that can be included in an SMTP response
1800 log_msg a message for logging
1802 Returns: 0 in most cases
1803 2 if the failure code was FAIL_DROP, in which case the
1804 SMTP connection should be dropped (this value fits with the
1805 "done" variable in smtp_setup_msg() below)
1809 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1811 int code = acl_wherecodes[where];
1812 BOOL drop = rc == FAIL_DROP;
1814 uschar *sender_info = US"";
1815 uschar *what = (where == ACL_WHERE_PREDATA)? US"DATA" :
1816 #ifdef WITH_CONTENT_SCAN
1817 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1819 (where == ACL_WHERE_DATA)? US"after DATA" :
1820 string_sprintf("%s %s", acl_wherenames[where], smtp_data);
1822 if (drop) rc = FAIL;
1824 /* We used to have sender_address here; however, there was a bug that was not
1825 updating sender_address after a rewrite during a verify. When this bug was
1826 fixed, sender_address at this point became the rewritten address. I'm not sure
1827 this is what should be logged, so I've changed to logging the unrewritten
1828 address to retain backward compatibility. */
1830 #ifndef WITH_CONTENT_SCAN
1831 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1833 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1836 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1837 sender_address_unrewritten : sender_address);
1840 /* If there's been a sender verification failure with a specific message, and
1841 we have not sent a response about it yet, do so now, as a preliminary line for
1842 failures, but not defers. However, log it in both cases. */
1844 if (sender_verified_failed != NULL &&
1845 !testflag(sender_verified_failed, af_sverify_told))
1847 setflag(sender_verified_failed, af_sverify_told);
1849 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1850 host_and_ident(TRUE),
1851 ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail",
1852 sender_verified_failed->address,
1853 (sender_verified_failed->message == NULL)? US"" :
1854 string_sprintf(": %s", sender_verified_failed->message));
1856 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1857 smtp_respond(code, FALSE, string_sprintf(
1858 testflag(sender_verified_failed, af_verify_pmfail)?
1859 "Postmaster verification failed while checking <%s>\n%s\n"
1860 "Several RFCs state that you are required to have a postmaster\n"
1861 "mailbox for each mail domain. This host does not accept mail\n"
1862 "from domains whose servers reject the postmaster address."
1864 testflag(sender_verified_failed, af_verify_nsfail)?
1865 "Callback setup failed while verifying <%s>\n%s\n"
1866 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1867 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1868 "RFC requirements, and stops you from receiving standard bounce\n"
1869 "messages. This host does not accept mail from domains whose servers\n"
1872 "Verification failed for <%s>\n%s",
1873 sender_verified_failed->address,
1874 sender_verified_failed->user_message));
1877 /* Sort out text for logging */
1879 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1880 lognl = Ustrchr(log_msg, '\n');
1881 if (lognl != NULL) *lognl = 0;
1883 /* Send permanent failure response to the command, but the code used isn't
1884 always a 5xx one - see comments at the start of this function. If the original
1885 rc was FAIL_DROP we drop the connection and yield 2. */
1887 if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1888 US"Administrative prohibition" : user_msg);
1890 /* Send temporary failure response to the command. Don't give any details,
1891 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1892 verb, and for a header verify when smtp_return_error_details is set.
1894 This conditional logic is all somewhat of a mess because of the odd
1895 interactions between temp_details and return_error_details. One day it should
1896 be re-implemented in a tidier fashion. */
1900 if (acl_temp_details && user_msg != NULL)
1902 if (smtp_return_error_details &&
1903 sender_verified_failed != NULL &&
1904 sender_verified_failed->message != NULL)
1906 smtp_respond(451, FALSE, sender_verified_failed->message);
1908 smtp_respond(451, TRUE, user_msg);
1911 smtp_printf("451 Temporary local problem - please try later\r\n");
1914 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
1915 Otherwise, log why it is closing if required and return 2. */
1917 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1918 host_and_ident(TRUE),
1919 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1921 if (!drop) return 0;
1923 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1924 smtp_get_connection_info());
1931 /*************************************************
1932 * Initialize for SMTP incoming message *
1933 *************************************************/
1935 /* This function conducts the initial dialogue at the start of an incoming SMTP
1936 message, and builds a list of recipients. However, if the incoming message
1937 is part of a batch (-bS option) a separate function is called since it would
1938 be messy having tests splattered about all over this function. This function
1939 therefore handles the case where interaction is occurring. The input and output
1940 files are set up in smtp_in and smtp_out.
1942 The global recipients_list is set to point to a vector of recipient_item
1943 blocks, whose number is given by recipients_count. This is extended by the
1944 receive_add_recipient() function. The global variable sender_address is set to
1945 the sender's address. The yield is +1 if a message has been successfully
1946 started, 0 if a QUIT command was encountered or the connection was refused from
1947 the particular host, or -1 if the connection was lost.
1951 Returns: > 0 message successfully started (reached DATA)
1952 = 0 QUIT read or end of file reached or call refused
1957 smtp_setup_msg(void)
1960 BOOL toomany = FALSE;
1961 BOOL discarded = FALSE;
1962 BOOL last_was_rej_mail = FALSE;
1963 BOOL last_was_rcpt = FALSE;
1964 void *reset_point = store_get(0);
1966 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
1968 /* Reset for start of new message. We allow one RSET not to be counted as a
1969 nonmail command, for those MTAs that insist on sending it between every
1970 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
1971 TLS between messages (an Exim client may do this if it has messages queued up
1972 for the host). Note: we do NOT reset AUTH at this point. */
1974 smtp_reset(reset_point);
1975 message_ended = END_NOTSTARTED;
1977 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
1978 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
1979 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
1981 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
1984 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
1986 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
1988 /* Batched SMTP is handled in a different function. */
1990 if (smtp_batched_input) return smtp_setup_batch_msg();
1992 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1993 value. The values are 2 larger than the required yield of the function. */
1998 uschar *etrn_command;
1999 uschar *etrn_serialize_key;
2001 uschar *user_msg, *log_msg;
2002 uschar *recipient = NULL;
2003 uschar *hello = NULL;
2004 uschar *set_id = NULL;
2006 BOOL was_rej_mail = FALSE;
2007 BOOL was_rcpt = FALSE;
2008 void (*oldsignal)(int);
2010 int start, end, sender_domain, recipient_domain;
2015 switch(smtp_read_command(TRUE))
2017 /* The AUTH command is not permitted to occur inside a transaction, and may
2018 occur successfully only once per connection, and then only when we've
2019 advertised it. Actually, that isn't quite true. When TLS is started, all
2020 previous information about a connection must be discarded, so a new AUTH is
2021 permitted at that time.
2023 AUTH is initially labelled as a "nonmail command" so that one occurrence
2024 doesn't get counted. We change the label here so that multiple failing
2025 AUTHS will eventually hit the nonmail threshold. */
2028 authentication_failed = TRUE;
2029 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2031 if (!auth_advertised)
2033 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2034 US"AUTH command used when not advertised");
2037 if (sender_host_authenticated != NULL)
2039 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2040 US"already authenticated");
2043 if (sender_address != NULL)
2045 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2046 US"not permitted in mail transaction");
2052 if (acl_smtp_auth != NULL)
2054 rc = acl_check(ACL_WHERE_AUTH, smtp_data, acl_smtp_auth, &user_msg,
2058 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2063 /* Find the name of the requested authentication mechanism. */
2066 while ((c = *smtp_data) != 0 && !isspace(c))
2068 if (!isalnum(c) && c != '-' && c != '_')
2070 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2071 US"invalid character in authentication mechanism name");
2077 /* If not at the end of the line, we must be at white space. Terminate the
2078 name and move the pointer on to any data that may be present. */
2080 if (*smtp_data != 0)
2083 while (isspace(*smtp_data)) smtp_data++;
2086 /* Search for an authentication mechanism which is configured for use
2087 as a server and which has been advertised. */
2089 for (au = auths; au != NULL; au = au->next)
2091 if (strcmpic(s, au->public_name) == 0 && au->server &&
2092 au->advertised) break;
2097 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2098 string_sprintf("%s authentication mechanism not supported", s));
2102 /* Run the checking code, passing the remainder of the command
2103 line as data. Initialize $0 empty. The authenticator may set up
2104 other numeric variables. Afterwards, have a go at expanding the set_id
2105 string, even if authentication failed - for bad passwords it can be useful
2106 to log the userid. On success, require set_id to expand and exist, and
2107 put it in authenticated_id. Save this in permanent store, as the working
2108 store gets reset at HELO, RSET, etc. */
2111 expand_nlength[0] = 0; /* $0 contains nothing */
2113 c = (au->info->servercode)(au, smtp_data);
2114 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2115 expand_nmax = -1; /* Reset numeric variables */
2117 /* The value of authenticated_id is stored in the spool file and printed in
2118 log lines. It must not contain binary zeros or newline characters. In
2119 normal use, it never will, but when playing around or testing, this error
2120 can (did) happen. To guard against this, ensure that the id contains only
2121 printing characters. */
2123 if (set_id != NULL) set_id = string_printing(set_id);
2125 /* For the non-OK cases, set up additional logging data if set_id
2130 if (set_id != NULL && *set_id != 0)
2131 set_id = string_sprintf(" (set_id=%s)", set_id);
2135 /* Switch on the result */
2140 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2142 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2143 sender_host_authenticated = au->name;
2144 authentication_failed = FALSE;
2146 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2147 ((sender_host_address != NULL)? pnlocal : 0);
2148 s = ss = US"235 Authentication succeeded";
2149 authenticated_by = au;
2153 /* Authentication succeeded, but we failed to expand the set_id string.
2154 Treat this as a temporary error. */
2156 auth_defer_msg = expand_string_message;
2160 s = string_sprintf("435 Unable to authenticate at present%s",
2161 auth_defer_user_msg);
2162 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2163 set_id, auth_defer_msg);
2167 s = ss = US"501 Invalid base64 data";
2171 s = ss = US"501 Authentication cancelled";
2175 s = ss = US"553 Initial data not expected";
2179 s = US"535 Incorrect authentication data";
2180 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2184 s = US"435 Internal error";
2185 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2186 "check", set_id, c);
2190 smtp_printf("%s\r\n", s);
2192 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2193 au->name, host_and_ident(FALSE), ss);
2195 break; /* AUTH_CMD */
2197 /* The HELO/EHLO commands are permitted to appear in the middle of a
2198 session as well as at the beginning. They have the effect of a reset in
2199 addition to their other functions. Their absence at the start cannot be
2200 taken to be an error.
2204 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2205 or 502 failure replies MUST be returned as appropriate. The SMTP
2206 server MUST stay in the same state after transmitting these replies
2207 that it was in before the EHLO was received.
2209 Therefore, we do not do the reset until after checking the command for
2210 acceptability. This change was made for Exim release 4.11. Previously
2211 it did the reset first. */
2222 HELO_EHLO: /* Common code for HELO and EHLO */
2223 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2224 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2226 /* Reject the HELO if its argument was invalid or non-existent. A
2227 successful check causes the argument to be saved in malloc store. */
2229 if (!check_helo(smtp_data))
2231 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2233 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2234 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2235 (*smtp_data == 0)? US"(no argument given)" :
2236 string_printing(smtp_data));
2238 if (++synprot_error_count > smtp_max_synprot_errors)
2240 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2241 "syntax or protocol errors (last command was \"%s\")",
2242 host_and_ident(FALSE), cmd_buffer);
2249 /* If sender_host_unknown is true, we have got here via the -bs interface,
2250 not called from inetd. Otherwise, we are running an IP connection and the
2251 host address will be set. If the helo name is the primary name of this
2252 host and we haven't done a reverse lookup, force one now. If helo_required
2253 is set, ensure that the HELO name matches the actual host. If helo_verify
2254 is set, do the same check, but softly. */
2256 if (!sender_host_unknown)
2258 BOOL old_helo_verified = helo_verified;
2259 uschar *p = smtp_data;
2261 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2264 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2265 because otherwise the log can be confusing. */
2267 if (sender_host_name == NULL &&
2268 (deliver_domain = sender_helo_name, /* set $domain */
2269 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2270 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2271 (void)host_name_lookup();
2273 /* Rebuild the fullhost info to include the HELO name (and the real name
2274 if it was looked up.) */
2276 host_build_sender_fullhost(); /* Rebuild */
2277 set_process_info("handling%s incoming connection from %s",
2278 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2280 /* Verify if configured. This doesn't give much security, but it does
2281 make some people happy to be able to do it. Note that HELO is legitimately
2282 allowed to quote an address literal. Allow for IPv6 ::ffff: literals. */
2284 helo_verified = FALSE;
2285 if (helo_required || helo_verify)
2287 BOOL tempfail = FALSE;
2289 HDEBUG(D_receive) debug_printf("verifying %s %s\n", hello,
2291 if (sender_helo_name[0] == '[')
2293 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2294 Ustrlen(sender_host_address)) == 0;
2299 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2300 helo_verified = Ustrncmp(sender_helo_name + 1,
2301 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2306 { if (helo_verified) debug_printf("matched host address\n"); }
2309 /* Do a reverse lookup if one hasn't already given a positive or
2310 negative response. If that fails, or the name doesn't match, try
2311 checking with a forward lookup. */
2315 if (sender_host_name == NULL && !host_lookup_failed)
2316 tempfail = host_name_lookup() == DEFER;
2318 /* If a host name is known, check it and all its aliases. */
2320 if (sender_host_name != NULL)
2322 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2326 HDEBUG(D_receive) debug_printf("matched host name\n");
2330 uschar **aliases = sender_host_aliases;
2331 while (*aliases != NULL)
2333 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2334 if (helo_verified) break;
2339 debug_printf("matched alias %s\n", *(--aliases));
2344 /* Final attempt: try a forward lookup of the helo name */
2350 h.name = sender_helo_name;
2354 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2356 rc = host_find_byname(&h, NULL, NULL, TRUE);
2357 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2362 if (Ustrcmp(hh->address, sender_host_address) == 0)
2364 helo_verified = TRUE;
2366 debug_printf("IP address for %s matches calling address\n",
2376 /* Verification failed. A temporary lookup failure gives a temporary
2383 smtp_printf("%d %s argument does not match calling host\r\n",
2384 tempfail? 451 : 550, hello);
2385 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2386 tempfail? "temporarily " : "",
2387 hello, sender_helo_name, host_and_ident(FALSE));
2388 helo_verified = old_helo_verified;
2389 break; /* End of HELO/EHLO processing */
2391 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2392 "helo_try_verify_hosts\n", hello);
2397 #ifdef EXPERIMENTAL_SPF
2398 /* set up SPF context */
2399 spf_init(sender_helo_name, sender_host_address);
2402 /* Apply an ACL check if one is defined */
2404 if (acl_smtp_helo != NULL)
2406 rc = acl_check(ACL_WHERE_HELO, smtp_data, acl_smtp_helo, &user_msg,
2410 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2411 sender_helo_name = NULL;
2412 host_build_sender_fullhost(); /* Rebuild */
2417 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2418 abandoning any previous message. */
2420 received_protocol = (esmtp?
2422 ((sender_host_authenticated != NULL)? pauthed : 0) +
2423 ((tls_active >= 0)? pcrpted : 0)]
2425 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2427 ((sender_host_address != NULL)? pnlocal : 0);
2429 smtp_reset(reset_point);
2432 /* Generate an OK reply, including the ident if present, and also
2433 the IP address if present. Reflecting back the ident is intended
2434 as a deterrent to mail forgers. For maximum efficiency, and also
2435 because some broken systems expect each response to be in a single
2436 packet, arrange that it is sent in one write(). */
2438 auth_advertised = FALSE;
2439 pipelining_advertised = FALSE;
2441 tls_advertised = FALSE;
2444 s = string_sprintf("250 %s Hello %s%s%s",
2445 smtp_active_hostname,
2446 (sender_ident == NULL)? US"" : sender_ident,
2447 (sender_ident == NULL)? US"" : US" at ",
2448 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2453 if (sender_host_address != NULL)
2455 s = string_cat(s, &size, &ptr, US" [", 2);
2456 s = string_cat(s, &size, &ptr, sender_host_address,
2457 Ustrlen(sender_host_address));
2458 s = string_cat(s, &size, &ptr, US"]", 1);
2461 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2463 /* If we received EHLO, we must create a multiline response which includes
2464 the functions supported. */
2470 /* I'm not entirely happy with this, as an MTA is supposed to check
2471 that it has enough room to accept a message of maximum size before
2472 it sends this. However, there seems little point in not sending it.
2473 The actual size check happens later at MAIL FROM time. By postponing it
2474 till then, VRFY and EXPN can be used after EHLO when space is short. */
2476 if (thismessage_size_limit > 0)
2478 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2479 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2483 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2486 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2487 clean; if it has an 8-bit character in its hand, it just sends it. It
2488 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2489 However, some users want this option simply in order to stop MUAs
2490 mangling messages that contain top-bit-set characters. It is therefore
2491 provided as an option. */
2493 if (accept_8bitmime)
2494 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2496 /* Advertise ETRN if there's an ACL checking whether a host is
2497 permitted to issue it; a check is made when any host actually tries. */
2499 if (acl_smtp_etrn != NULL)
2501 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2504 /* Advertise EXPN if there's an ACL checking whether a host is
2505 permitted to issue it; a check is made when any host actually tries. */
2507 if (acl_smtp_expn != NULL)
2509 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2512 /* Exim is quite happy with pipelining, so let the other end know that
2513 it is safe to use it, unless advertising is disabled. */
2515 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2517 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2518 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2519 pipelining_advertised = TRUE;
2522 /* If any server authentication mechanisms are configured, advertise
2523 them if the current host is in auth_advertise_hosts. The problem with
2524 advertising always is that some clients then require users to
2525 authenticate (and aren't configurable otherwise) even though it may not
2526 be necessary (e.g. if the host is in host_accept_relay).
2528 RFC 2222 states that SASL mechanism names contain only upper case
2529 letters, so output the names in upper case, though we actually recognize
2530 them in either case in the AUTH command. */
2534 if (verify_check_host(&auth_advertise_hosts) == OK)
2538 for (au = auths; au != NULL; au = au->next)
2540 if (au->server && (au->advertise_condition == NULL ||
2541 expand_check_condition(au->advertise_condition, au->name,
2542 US"authenticator")))
2547 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2549 auth_advertised = TRUE;
2552 s = string_cat(s, &size, &ptr, US" ", 1);
2553 s = string_cat(s, &size, &ptr, au->public_name,
2554 Ustrlen(au->public_name));
2555 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2556 au->advertised = TRUE;
2558 else au->advertised = FALSE;
2560 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2564 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2565 if it has been included in the binary, and the host matches
2566 tls_advertise_hosts. We must *not* advertise if we are already in a
2567 secure connection. */
2570 if (tls_active < 0 &&
2571 verify_check_host(&tls_advertise_hosts) != FAIL)
2573 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2574 tls_advertised = TRUE;
2578 /* Finish off the multiline reply with one that is always available. */
2580 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2583 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2589 if (tls_active >= 0) (void)tls_write(s, ptr); else
2592 fwrite(s, 1, ptr, smtp_out);
2593 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2595 break; /* HELO/EHLO */
2598 /* The MAIL command requires an address as an operand. All we do
2599 here is to parse it for syntactic correctness. The form "<>" is
2600 a special case which converts into an empty string. The start/end
2601 pointers in the original are not used further for this address, as
2602 it is the canonical extracted address which is all that is kept. */
2605 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2606 was_rej_mail = TRUE; /* Reset if accepted */
2608 if (helo_required && !helo_seen)
2610 smtp_printf("503 HELO or EHLO required\r\n");
2611 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2612 "HELO/EHLO given", host_and_ident(FALSE));
2616 if (sender_address != NULL)
2618 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2619 US"sender already given");
2623 if (smtp_data[0] == 0)
2625 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2626 US"MAIL must have an address operand");
2630 /* Check to see if the limit for messages per connection would be
2631 exceeded by accepting further messages. */
2633 if (smtp_accept_max_per_connection > 0 &&
2634 smtp_mailcmd_count > smtp_accept_max_per_connection)
2636 smtp_printf("421 too many messages in this connection\r\n");
2637 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2638 "messages in one connection", host_and_ident(TRUE));
2642 /* Reset for start of message - even if this is going to fail, we
2643 obviously need to throw away any previous data. */
2645 smtp_reset(reset_point);
2647 sender_data = recipient_data = NULL;
2649 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2653 uschar *name, *value, *end;
2654 unsigned long int size;
2656 if (!extract_option(&name, &value)) break;
2658 /* Handle SIZE= by reading the value. We don't do the check till later,
2659 in order to be able to log the sender address on failure. */
2661 if (strcmpic(name, US"SIZE") == 0 &&
2662 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2664 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2666 message_size = (int)size;
2669 /* If this session was initiated with EHLO and accept_8bitmime is set,
2670 Exim will have indicated that it supports the BODY=8BITMIME option. In
2671 fact, it does not support this according to the RFCs, in that it does not
2672 take any special action for forwarding messages containing 8-bit
2673 characters. That is why accept_8bitmime is not the default setting, but
2674 some sites want the action that is provided. We recognize both "8BITMIME"
2675 and "7BIT" as body types, but take no action. */
2677 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2678 (strcmpic(value, US"8BITMIME") == 0 ||
2679 strcmpic(value, US"7BIT") == 0)) {}
2681 /* Handle the AUTH extension. If the value given is not "<>" and either
2682 the ACL says "yes" or there is no ACL but the sending host is
2683 authenticated, we set it up as the authenticated sender. However, if the
2684 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2685 the condition is met. The value of AUTH is an xtext, which means that +,
2686 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2689 else if (strcmpic(name, US"AUTH") == 0)
2691 if (Ustrcmp(value, "<>") != 0)
2696 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2698 /* Put back terminator overrides for error message */
2701 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2702 US"invalid data for AUTH");
2706 if (acl_smtp_mailauth == NULL)
2708 ignore_msg = US"client not authenticated";
2709 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2713 ignore_msg = US"rejected by ACL";
2714 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2715 &user_msg, &log_msg);
2721 if (authenticated_by == NULL ||
2722 authenticated_by->mail_auth_condition == NULL ||
2723 expand_check_condition(authenticated_by->mail_auth_condition,
2724 authenticated_by->name, US"authenticator"))
2725 break; /* Accept the AUTH */
2727 ignore_msg = US"server_mail_auth_condition failed";
2728 if (authenticated_id != NULL)
2729 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2730 ignore_msg, authenticated_id);
2735 authenticated_sender = NULL;
2736 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2737 value, host_and_ident(TRUE), ignore_msg);
2740 /* Should only get DEFER or ERROR here. Put back terminator
2741 overrides for error message */
2746 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2753 /* Unknown option. Stick back the terminator characters and break
2754 the loop. An error for a malformed address will occur. */
2764 /* If we have passed the threshold for rate limiting, apply the current
2765 delay, and update it for next time, provided this is a limited host. */
2767 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2768 verify_check_host(&smtp_ratelimit_hosts) == OK)
2770 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2771 smtp_delay_mail/1000.0);
2772 millisleep((int)smtp_delay_mail);
2773 smtp_delay_mail *= smtp_rlm_factor;
2774 if (smtp_delay_mail > (double)smtp_rlm_limit)
2775 smtp_delay_mail = (double)smtp_rlm_limit;
2778 /* Now extract the address, first applying any SMTP-time rewriting. The
2779 TRUE flag allows "<>" as a sender address. */
2781 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2782 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2783 global_rewrite_rules) : smtp_data;
2785 /* rfc821_domains = TRUE; << no longer needed */
2787 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2789 /* rfc821_domains = FALSE; << no longer needed */
2791 if (raw_sender == NULL)
2793 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2797 sender_address = raw_sender;
2799 /* If there is a configured size limit for mail, check that this message
2800 doesn't exceed it. The check is postponed to this point so that the sender
2803 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2805 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2806 log_write(L_size_reject,
2807 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2808 "message too big: size%s=%d max=%d",
2810 host_and_ident(TRUE),
2811 (message_size == INT_MAX)? ">" : "",
2813 thismessage_size_limit);
2814 sender_address = NULL;
2818 /* Check there is enough space on the disk unless configured not to.
2819 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2820 plus the current message - i.e. we accept the message only if it won't
2821 reduce the space below the threshold. Add 5000 to the size to allow for
2822 overheads such as the Received: line and storing of recipients, etc.
2823 By putting the check here, even when SIZE is not given, it allow VRFY
2824 and EXPN etc. to be used when space is short. */
2826 if (!receive_check_fs(
2827 (smtp_check_spool_space && message_size >= 0)?
2828 message_size + 5000 : 0))
2830 smtp_printf("452 Space shortage, please try later\r\n");
2831 sender_address = NULL;
2835 /* If sender_address is unqualified, reject it, unless this is a locally
2836 generated message, or the sending host or net is permitted to send
2837 unqualified addresses - typically local machines behaving as MUAs -
2838 in which case just qualify the address. The flag is set above at the start
2839 of the SMTP connection. */
2841 if (sender_domain == 0 && sender_address[0] != 0)
2843 if (allow_unqualified_sender)
2845 sender_domain = Ustrlen(sender_address) + 1;
2846 sender_address = rewrite_address_qualify(sender_address, FALSE);
2847 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2852 smtp_printf("501 %s: sender address must contain a domain\r\n",
2854 log_write(L_smtp_syntax_error,
2855 LOG_MAIN|LOG_REJECT,
2856 "unqualified sender rejected: <%s> %s%s",
2858 host_and_ident(TRUE),
2860 sender_address = NULL;
2865 /* Apply an ACL check if one is defined, before responding */
2867 rc = (acl_smtp_mail == NULL)? OK :
2868 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2870 if (rc == OK || rc == DISCARD)
2872 smtp_printf("250 OK\r\n");
2873 smtp_delay_rcpt = smtp_rlr_base;
2874 recipients_discarded = (rc == DISCARD);
2875 was_rej_mail = FALSE;
2880 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2881 sender_address = NULL;
2886 /* The RCPT command requires an address as an operand. All we do
2887 here is to parse it for syntactic correctness. There may be any number
2888 of RCPT commands, specifying multiple senders. We build them all into
2889 a data structure that is in argc/argv format. The start/end values
2890 given by parse_extract_address are not used, as we keep only the
2891 extracted address. */
2897 /* There must be a sender address; if the sender was rejected and
2898 pipelining was advertised, we assume the client was pipelining, and do not
2899 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2900 get the same treatment. */
2902 if (sender_address == NULL)
2904 if (pipelining_advertised && last_was_rej_mail)
2906 smtp_printf("503 sender not yet given\r\n");
2907 was_rej_mail = TRUE;
2911 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2912 US"sender not yet given");
2913 was_rcpt = FALSE; /* Not a valid RCPT */
2919 /* Check for an operand */
2921 if (smtp_data[0] == 0)
2923 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2924 US"RCPT must have an address operand");
2929 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2930 as a recipient address */
2932 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2933 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2934 global_rewrite_rules) : smtp_data;
2936 /* rfc821_domains = TRUE; << no longer needed */
2937 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2938 &recipient_domain, FALSE);
2939 /* rfc821_domains = FALSE; << no longer needed */
2941 if (recipient == NULL)
2943 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2948 /* If the recipient address is unqualified, reject it, unless this is a
2949 locally generated message. However, unqualified addresses are permitted
2950 from a configured list of hosts and nets - typically when behaving as
2951 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2952 really. The flag is set at the start of the SMTP connection.
2954 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2955 assumed this meant "reserved local part", but the revision of RFC 821 and
2956 friends now makes it absolutely clear that it means *mailbox*. Consequently
2957 we must always qualify this address, regardless. */
2959 if (recipient_domain == 0)
2961 if (allow_unqualified_recipient ||
2962 strcmpic(recipient, US"postmaster") == 0)
2964 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2966 recipient_domain = Ustrlen(recipient) + 1;
2967 recipient = rewrite_address_qualify(recipient, TRUE);
2972 smtp_printf("501 %s: recipient address must contain a domain\r\n",
2974 log_write(L_smtp_syntax_error,
2975 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
2976 "<%s> %s%s", recipient, host_and_ident(TRUE),
2982 /* Check maximum allowed */
2984 if (rcpt_count > recipients_max && recipients_max > 0)
2986 if (recipients_max_reject)
2989 smtp_printf("552 too many recipients\r\n");
2991 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
2992 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
2997 smtp_printf("452 too many recipients\r\n");
2999 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3000 "temporarily rejected: sender=<%s> %s", sender_address,
3001 host_and_ident(TRUE));
3008 /* If we have passed the threshold for rate limiting, apply the current
3009 delay, and update it for next time, provided this is a limited host. */
3011 if (rcpt_count > smtp_rlr_threshold &&
3012 verify_check_host(&smtp_ratelimit_hosts) == OK)
3014 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3015 smtp_delay_rcpt/1000.0);
3016 millisleep((int)smtp_delay_rcpt);
3017 smtp_delay_rcpt *= smtp_rlr_factor;
3018 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3019 smtp_delay_rcpt = (double)smtp_rlr_limit;
3022 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3023 for them. Otherwise, check the access control list for this recipient. */
3025 rc = recipients_discarded? DISCARD :
3026 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3028 /* The ACL was happy */
3032 smtp_printf("250 Accepted\r\n");
3033 receive_add_recipient(recipient, -1);
3036 /* The recipient was discarded */
3038 else if (rc == DISCARD)
3040 smtp_printf("250 Accepted\r\n");
3043 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3044 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3045 (sender_address_unrewritten != NULL)?
3046 sender_address_unrewritten : sender_address,
3047 smtp_data, recipients_discarded? "MAIL" : "RCPT",
3048 (log_msg == NULL)? US"" : US": ",
3049 (log_msg == NULL)? US"" : log_msg);
3052 /* Either the ACL failed the address, or it was deferred. */
3056 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3057 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3062 /* The DATA command is legal only if it follows successful MAIL FROM
3063 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3064 not counted as a protocol error if it follows RCPT (which must have been
3065 rejected if there are no recipients.) This function is complete when a
3066 valid DATA command is encountered.
3068 Note concerning the code used: RFC 2821 says this:
3070 - If there was no MAIL, or no RCPT, command, or all such commands
3071 were rejected, the server MAY return a "command out of sequence"
3072 (503) or "no valid recipients" (554) reply in response to the
3075 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3076 because it is the same whether pipelining is in use or not. */
3079 if (!discarded && recipients_count <= 0)
3081 if (pipelining_advertised && last_was_rcpt)
3082 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3084 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3085 US"valid RCPT command must precede DATA");
3089 if (toomany && recipients_max_reject)
3091 sender_address = NULL; /* This will allow a new MAIL without RSET */
3092 sender_address_unrewritten = NULL;
3093 smtp_printf("554 Too many recipients\r\n");
3097 if (acl_smtp_predata == NULL) rc = OK; else
3099 enable_dollar_recipients = TRUE;
3100 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3102 enable_dollar_recipients = FALSE;
3107 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3109 message_ended = END_NOTENDED; /* Indicate in middle of data */
3112 /* Either the ACL failed the address, or it was deferred. */
3115 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3121 rc = acl_check(ACL_WHERE_VRFY, smtp_data, acl_smtp_vrfy, &user_msg,
3124 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3130 /* rfc821_domains = TRUE; << no longer needed */
3131 address = parse_extract_address(smtp_data, &errmess, &start, &end,
3132 &recipient_domain, FALSE);
3133 /* rfc821_domains = FALSE; << no longer needed */
3135 if (address == NULL)
3136 s = string_sprintf("501 %s", errmess);
3139 address_item *addr = deliver_make_addr(address, FALSE);
3140 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3141 -1, -1, NULL, NULL, NULL))
3144 s = string_sprintf("250 <%s> is deliverable", address);
3148 s = (addr->message != NULL)?
3149 string_sprintf("451 <%s> %s", address, addr->message) :
3150 string_sprintf("451 Cannot resolve <%s> at this time", address);
3154 s = (addr->message != NULL)?
3155 string_sprintf("550 <%s> %s", address, addr->message) :
3156 string_sprintf("550 <%s> is not deliverable", address);
3157 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3158 smtp_data, host_and_ident(TRUE));
3163 smtp_printf("%s\r\n", s);
3169 rc = acl_check(ACL_WHERE_EXPN, smtp_data, acl_smtp_expn, &user_msg,
3172 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3175 BOOL save_log_testing_mode = log_testing_mode;
3176 address_test_mode = log_testing_mode = TRUE;
3177 (void) verify_address(deliver_make_addr(smtp_data, FALSE), smtp_out,
3178 vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1, NULL, NULL,
3180 address_test_mode = FALSE;
3181 log_testing_mode = save_log_testing_mode; /* true for -bh */
3189 if (!tls_advertised)
3191 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3192 US"STARTTLS command used when not advertised");
3196 /* Apply an ACL check if one is defined */
3198 if (acl_smtp_starttls != NULL)
3200 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3204 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3209 /* RFC 2487 is not clear on when this command may be sent, though it
3210 does state that all information previously obtained from the client
3211 must be discarded if a TLS session is started. It seems reasonble to
3212 do an implied RSET when STARTTLS is received. */
3214 incomplete_transaction_log(US"STARTTLS");
3215 smtp_reset(reset_point);
3217 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3219 /* Attempt to start up a TLS session, and if successful, discard all
3220 knowledge that was obtained previously. At least, that's what the RFC says,
3221 and that's what happens by default. However, in order to work round YAEB,
3222 there is an option to remember the esmtp state. Sigh.
3224 We must allow for an extra EHLO command and an extra AUTH command after
3225 STARTTLS that don't add to the nonmail command count. */
3227 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3229 if (!tls_remember_esmtp)
3230 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3231 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3232 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3233 if (sender_helo_name != NULL)
3235 store_free(sender_helo_name);
3236 sender_helo_name = NULL;
3237 host_build_sender_fullhost(); /* Rebuild */
3238 set_process_info("handling incoming TLS connection from %s",
3239 host_and_ident(FALSE));
3241 received_protocol = (esmtp?
3242 protocols[pextend + pcrpted +
3243 ((sender_host_authenticated != NULL)? pauthed : 0)]
3245 protocols[pnormal + pcrpted])
3247 ((sender_host_address != NULL)? pnlocal : 0);
3249 sender_host_authenticated = NULL;
3250 authenticated_id = NULL;
3251 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3252 DEBUG(D_tls) debug_printf("TLS active\n");
3253 break; /* Successful STARTTLS */
3256 /* Some local configuration problem was discovered before actually trying
3257 to do a TLS handshake; give a temporary error. */
3259 else if (rc == DEFER)
3261 smtp_printf("454 TLS currently unavailable\r\n");
3265 /* Hard failure. Reject everything except QUIT or closed connection. One
3266 cause for failure is a nested STARTTLS, in which case tls_active remains
3267 set, but we must still reject all incoming commands. */
3269 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3272 switch(smtp_read_command(FALSE))
3275 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3276 smtp_get_connection_info());
3281 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3282 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3283 smtp_get_connection_info());
3288 smtp_printf("554 Security failure\r\n");
3297 /* The ACL for QUIT is provided for gathering statistical information or
3298 similar; it does not affect the response code, but it can supply a custom
3302 incomplete_transaction_log(US"QUIT");
3304 if (acl_smtp_quit != NULL)
3306 rc = acl_check(ACL_WHERE_QUIT, US"", acl_smtp_quit,&user_msg,&log_msg);
3308 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3311 else user_msg = NULL;
3313 if (user_msg == NULL)
3314 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3316 smtp_printf("221 %s\r\n", user_msg);
3323 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3324 smtp_get_connection_info());
3329 incomplete_transaction_log(US"RSET");
3330 smtp_reset(reset_point);
3332 smtp_printf("250 Reset OK\r\n");
3333 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3338 smtp_printf("250 OK\r\n");
3342 /* Show ETRN/EXPN/VRFY if there's
3343 an ACL for checking hosts; if actually used, a check will be done for
3347 smtp_printf("214-Commands supported:\r\n");
3351 Ustrcat(buffer, " AUTH");
3353 Ustrcat(buffer, " STARTTLS");
3355 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3356 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3357 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3358 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3359 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3360 smtp_printf("214%s\r\n", buffer);
3366 incomplete_transaction_log(US"connection lost");
3367 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3369 /* Don't log by default unless in the middle of a message, as some mailers
3370 just drop the call rather than sending QUIT, and it clutters up the logs.
3373 if (sender_address != NULL || recipients_count > 0)
3374 log_write(L_lost_incoming_connection,
3376 "unexpected %s while reading SMTP command from %s%s",
3377 sender_host_unknown? "EOF" : "disconnection",
3378 host_and_ident(FALSE), smtp_read_error);
3380 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3381 smtp_get_connection_info(), smtp_read_error);
3388 if (sender_address != NULL)
3390 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3391 US"ETRN is not permitted inside a transaction");
3395 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_data,
3396 host_and_ident(FALSE));
3398 rc = acl_check(ACL_WHERE_ETRN, smtp_data, acl_smtp_etrn, &user_msg,
3402 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3406 /* Compute the serialization key for this command. */
3408 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_data);
3410 /* If a command has been specified for running as a result of ETRN, we
3411 permit any argument to ETRN. If not, only the # standard form is permitted,
3412 since that is strictly the only kind of ETRN that can be implemented
3413 according to the RFC. */
3415 if (smtp_etrn_command != NULL)
3419 etrn_command = smtp_etrn_command;
3420 deliver_domain = smtp_data;
3421 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3422 US"ETRN processing", &error);
3423 deliver_domain = NULL;
3426 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3428 smtp_printf("458 Internal failure\r\n");
3433 /* Else set up to call Exim with the -R option. */
3437 if (*smtp_data++ != '#')
3439 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3440 US"argument must begin with #");
3443 etrn_command = US"exim -R";
3444 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3448 /* If we are host-testing, don't actually do anything. */
3454 debug_printf("ETRN command is: %s\n", etrn_command);
3455 debug_printf("ETRN command execution skipped\n");
3457 smtp_printf("250 OK\r\n");
3462 /* If ETRN queue runs are to be serialized, check the database to
3463 ensure one isn't already running. */
3465 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3467 smtp_printf("458 Already processing %s\r\n", smtp_data);
3471 /* Fork a child process and run the command. We don't want to have to
3472 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3473 forking. It should be set that way anyway for external incoming SMTP,
3474 but we save and restore to be tidy. If serialization is required, we
3475 actually run the command in yet another process, so we can wait for it
3476 to complete and then remove the serialization lock. */
3478 oldsignal = signal(SIGCHLD, SIG_IGN);
3480 if ((pid = fork()) == 0)
3482 smtp_input = FALSE; /* This process is not associated with the */
3483 fclose(smtp_in); /* SMTP call any more. */
3486 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3488 /* If not serializing, do the exec right away. Otherwise, fork down
3489 into another process. */
3491 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3493 DEBUG(D_exec) debug_print_argv(argv);
3494 exim_nullstd(); /* Ensure std{in,out,err} exist */
3495 execv(CS argv[0], (char *const *)argv);
3496 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3497 etrn_command, strerror(errno));
3498 _exit(EXIT_FAILURE); /* paranoia */
3501 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3502 is, we are in the first subprocess, after forking again. All we can do
3503 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3504 complete, before removing the serialization. */
3507 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3508 "failed: %s", strerror(errno));
3512 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3514 (void)wait(&status);
3515 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3519 enq_end(etrn_serialize_key);
3520 _exit(EXIT_SUCCESS);
3523 /* Back in the top level SMTP process. Check that we started a subprocess
3524 and restore the signal state. */
3528 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3530 smtp_printf("458 Unable to fork process\r\n");
3531 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3533 else smtp_printf("250 OK\r\n");
3535 signal(SIGCHLD, oldsignal);
3540 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3541 US"unexpected argument data");
3545 /* This currently happens only for NULLs, but could be extended. */
3548 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3549 US"NULL character(s) present (shown as '?')");
3550 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3555 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3556 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3557 c = smtp_inend - smtp_inptr;
3558 if (c > 150) c = 150;
3560 incomplete_transaction_log(US"sync failure");
3561 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: "
3562 "synchronization error "
3563 "(next input sent too soon: pipelining was%s advertised): "
3564 "rejected \"%s\" %s next input=\"%s\"",
3565 pipelining_advertised? "" : " not",
3566 cmd_buffer, host_and_ident(TRUE),
3567 string_printing(smtp_inptr));
3568 smtp_printf("554 SMTP synchronization error\r\n");
3569 done = 1; /* Pretend eof - drops connection */
3573 case TOO_MANY_NONMAIL_CMD:
3574 incomplete_transaction_log(US"too many non-mail commands");
3575 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3576 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
3577 smtp_data - cmd_buffer, cmd_buffer);
3578 smtp_printf("554 Too many nonmail commands\r\n");
3579 done = 1; /* Pretend eof - drops connection */
3584 if (unknown_command_count++ >= smtp_max_unknown_commands)
3586 log_write(L_smtp_syntax_error, LOG_MAIN,
3587 "SMTP syntax error in \"%s\" %s %s",
3588 string_printing(cmd_buffer), host_and_ident(TRUE),
3589 US"unrecognized command");
3590 incomplete_transaction_log(US"unrecognized command");
3591 smtp_printf("500 Too many unrecognized commands\r\n");
3593 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3594 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3598 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3599 US"unrecognized command");
3603 /* This label is used by goto's inside loops that want to break out to
3604 the end of the command-processing loop. */
3607 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3608 last_was_rcpt = was_rcpt; /* protocol error handling */
3612 return done - 2; /* Convert yield values */
3615 /* End of smtp_in.c */