1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.19 2005/05/23 16:58:56 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 sender_rate = sender_rate_limit = sender_rate_period = NULL;
842 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
843 /* Note that ratelimiters_conn persists across resets. */
845 for (i = 0; i < ACL_M_MAX; i++) acl_var[ACL_C_MAX + i] = NULL;
847 /* The message body variables use malloc store. They may be set if this is
848 not the first message in an SMTP session and the previous message caused them
849 to be referenced in an ACL. */
851 if (message_body != NULL)
853 store_free(message_body);
857 if (message_body_end != NULL)
859 store_free(message_body_end);
860 message_body_end = NULL;
863 /* Warning log messages are also saved in malloc store. They are saved to avoid
864 repetition in the same message, but it seems right to repeat them for different
867 while (acl_warn_logged != NULL)
869 string_item *this = acl_warn_logged;
870 acl_warn_logged = acl_warn_logged->next;
879 /*************************************************
880 * Initialize for incoming batched SMTP message *
881 *************************************************/
883 /* This function is called from smtp_setup_msg() in the case when
884 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
885 of messages in one file with SMTP commands between them. All errors must be
886 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
887 relevant. After an error on a sender, or an invalid recipient, the remainder
888 of the message is skipped. The value of received_protocol is already set.
891 Returns: > 0 message successfully started (reached DATA)
892 = 0 QUIT read or end of file reached
897 smtp_setup_batch_msg(void)
900 void *reset_point = store_get(0);
902 /* Save the line count at the start of each transaction - single commands
903 like HELO and RSET count as whole transactions. */
905 bsmtp_transaction_linecount = receive_linecount;
907 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
909 smtp_reset(reset_point); /* Reset for start of message */
911 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
912 value. The values are 2 larger than the required yield of the function. */
917 uschar *recipient = NULL;
918 int start, end, sender_domain, recipient_domain;
920 switch(smtp_read_command(FALSE))
922 /* The HELO/EHLO commands set sender_address_helo if they have
923 valid data; otherwise they are ignored, except that they do
924 a reset of the state. */
929 check_helo(smtp_data);
933 smtp_reset(reset_point);
934 bsmtp_transaction_linecount = receive_linecount;
938 /* The MAIL FROM command requires an address as an operand. All we
939 do here is to parse it for syntactic correctness. The form "<>" is
940 a special case which converts into an empty string. The start/end
941 pointers in the original are not used further for this address, as
942 it is the canonical extracted address which is all that is kept. */
945 if (sender_address != NULL)
946 /* The function moan_smtp_batch() does not return. */
947 moan_smtp_batch(cmd_buffer, "503 Sender already given");
949 if (smtp_data[0] == 0)
950 /* The function moan_smtp_batch() does not return. */
951 moan_smtp_batch(cmd_buffer, "501 MAIL FROM must have an address operand");
953 /* Reset to start of message */
955 smtp_reset(reset_point);
957 /* Apply SMTP rewrite */
959 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
960 rewrite_one(smtp_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
961 US"", global_rewrite_rules) : smtp_data;
963 /* Extract the address; the TRUE flag allows <> as valid */
966 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
969 if (raw_sender == NULL)
970 /* The function moan_smtp_batch() does not return. */
971 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
973 sender_address = string_copy(raw_sender);
975 /* Qualify unqualified sender addresses if permitted to do so. */
977 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
979 if (allow_unqualified_sender)
981 sender_address = rewrite_address_qualify(sender_address, FALSE);
982 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
983 "and rewritten\n", raw_sender);
985 /* The function moan_smtp_batch() does not return. */
986 else moan_smtp_batch(cmd_buffer, "501 sender address must contain "
992 /* The RCPT TO command requires an address as an operand. All we do
993 here is to parse it for syntactic correctness. There may be any number
994 of RCPT TO commands, specifying multiple senders. We build them all into
995 a data structure that is in argc/argv format. The start/end values
996 given by parse_extract_address are not used, as we keep only the
997 extracted address. */
1000 if (sender_address == NULL)
1001 /* The function moan_smtp_batch() does not return. */
1002 moan_smtp_batch(cmd_buffer, "503 No sender yet given");
1004 if (smtp_data[0] == 0)
1005 /* The function moan_smtp_batch() does not return. */
1006 moan_smtp_batch(cmd_buffer, "501 RCPT TO must have an address operand");
1008 /* Check maximum number allowed */
1010 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1011 /* The function moan_smtp_batch() does not return. */
1012 moan_smtp_batch(cmd_buffer, "%s too many recipients",
1013 recipients_max_reject? "552": "452");
1015 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1016 recipient address */
1018 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1019 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
1020 global_rewrite_rules) : smtp_data;
1022 /* rfc821_domains = TRUE; << no longer needed */
1023 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1024 &recipient_domain, FALSE);
1025 /* rfc821_domains = FALSE; << no longer needed */
1027 if (recipient == NULL)
1028 /* The function moan_smtp_batch() does not return. */
1029 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
1031 /* If the recipient address is unqualified, qualify it if permitted. Then
1032 add it to the list of recipients. */
1034 if (recipient_domain == 0)
1036 if (allow_unqualified_recipient)
1038 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1040 recipient = rewrite_address_qualify(recipient, TRUE);
1042 /* The function moan_smtp_batch() does not return. */
1043 else moan_smtp_batch(cmd_buffer, "501 recipient address must contain "
1046 receive_add_recipient(recipient, -1);
1050 /* The DATA command is legal only if it follows successful MAIL FROM
1051 and RCPT TO commands. This function is complete when a valid DATA
1052 command is encountered. */
1055 if (sender_address == NULL || recipients_count <= 0)
1057 /* The function moan_smtp_batch() does not return. */
1058 if (sender_address == NULL)
1059 moan_smtp_batch(cmd_buffer,
1060 "503 MAIL FROM:<sender> command must precede DATA");
1062 moan_smtp_batch(cmd_buffer,
1063 "503 RCPT TO:<recipient> must precede DATA");
1067 done = 3; /* DATA successfully achieved */
1068 message_ended = END_NOTENDED; /* Indicate in middle of message */
1073 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1080 bsmtp_transaction_linecount = receive_linecount;
1091 /* The function moan_smtp_batch() does not return. */
1092 moan_smtp_batch(cmd_buffer, "501 Unexpected argument data");
1097 /* The function moan_smtp_batch() does not return. */
1098 moan_smtp_batch(cmd_buffer, "501 Unexpected NULL in SMTP command");
1103 /* The function moan_smtp_batch() does not return. */
1104 moan_smtp_batch(cmd_buffer, "500 Command unrecognized");
1109 return done - 2; /* Convert yield values */
1115 /*************************************************
1116 * Start an SMTP session *
1117 *************************************************/
1119 /* This function is called at the start of an SMTP session. Thereafter,
1120 smtp_setup_msg() is called to initiate each separate message. This
1121 function does host-specific testing, and outputs the banner line.
1124 Returns: FALSE if the session can not continue; something has
1125 gone wrong, or the connection to the host is blocked
1129 smtp_start_session(void)
1135 /* If we are running in the test harness, and the incoming call is from
1136 127.0.0.2 (sic), have a short delay. This makes it possible to test handling of
1137 input sent too soon (before the banner is output). */
1139 if (running_in_test_harness &&
1140 sender_host_address != NULL &&
1141 Ustrcmp(sender_host_address, "127.0.0.2") == 0)
1144 /* Default values for certain variables */
1146 helo_seen = esmtp = helo_accept_junk = FALSE;
1147 count_nonmail = TRUE_UNSET;
1148 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1149 smtp_delay_mail = smtp_rlm_base;
1150 auth_advertised = FALSE;
1151 pipelining_advertised = FALSE;
1152 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1154 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1156 sender_host_authenticated = NULL;
1157 authenticated_by = NULL;
1160 tls_cipher = tls_peerdn = NULL;
1161 tls_advertised = FALSE;
1164 /* Reset ACL connection variables */
1166 for (i = 0; i < ACL_C_MAX; i++) acl_var[i] = NULL;
1168 cmd_buffer = (uschar *)malloc(cmd_buffer_size + 1); /* allow for trailing 0 */
1169 if (cmd_buffer == NULL)
1170 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1171 "malloc() failed for SMTP command buffer");
1173 /* For batched input, the protocol setting can be overridden from the
1174 command line by a trusted caller. */
1176 if (smtp_batched_input)
1178 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1181 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1182 reset later if any of EHLO/AUTH/STARTTLS are received. */
1186 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1188 /* Set up the buffer for inputting using direct read() calls, and arrange to
1189 call the local functions instead of the standard C ones. */
1191 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1192 if (smtp_inbuffer == NULL)
1193 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1194 receive_getc = smtp_getc;
1195 receive_ungetc = smtp_ungetc;
1196 receive_feof = smtp_feof;
1197 receive_ferror = smtp_ferror;
1198 smtp_inptr = smtp_inend = smtp_inbuffer;
1199 smtp_had_eof = smtp_had_error = 0;
1201 /* Set up the message size limit; this may be host-specific */
1203 thismessage_size_limit = expand_string_integer(message_size_limit);
1204 if (thismessage_size_limit < 0)
1206 if (thismessage_size_limit == -1)
1207 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1208 "%s", expand_string_message);
1210 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1211 "%s", expand_string_message);
1212 smtp_closedown(US"Temporary local problem - please try later");
1216 /* When a message is input locally via the -bs or -bS options, sender_host_
1217 unknown is set unless -oMa was used to force an IP address, in which case it
1218 is checked like a real remote connection. When -bs is used from inetd, this
1219 flag is not set, causing the sending host to be checked. The code that deals
1220 with IP source routing (if configured) is never required for -bs or -bS and
1221 the flag sender_host_notsocket is used to suppress it.
1223 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1224 reserve for certain hosts and/or networks. */
1226 if (!sender_host_unknown)
1229 BOOL reserved_host = FALSE;
1231 /* Look up IP options (source routing info) on the socket if this is not an
1232 -oMa "host", and if any are found, log them and drop the connection.
1234 Linux (and others now, see below) is different to everyone else, so there
1235 has to be some conditional compilation here. Versions of Linux before 2.1.15
1236 used a structure whose name was "options". Somebody finally realized that
1237 this name was silly, and it got changed to "ip_options". I use the
1238 newer name here, but there is a fudge in the script that sets up os.h
1239 to define a macro in older Linux systems.
1241 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1242 glibc 2, which has chosen ip_opts for the structure name. This is now
1243 really a glibc thing rather than a Linux thing, so the condition name
1244 has been changed to reflect this. It is relevant also to GNU/Hurd.
1246 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1247 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1248 a special macro defined in the os.h file.
1250 Some DGUX versions on older hardware appear not to support IP options at
1251 all, so there is now a general macro which can be set to cut out this
1254 How to do this properly in IPv6 is not yet known. */
1256 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1258 #ifdef GLIBC_IP_OPTIONS
1259 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1264 #elif defined DARWIN_IP_OPTIONS
1270 if (!host_checking && !sender_host_notsocket)
1273 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1274 struct ip_options *ipopt = store_get(optlen);
1276 struct ip_opts ipoptblock;
1277 struct ip_opts *ipopt = &ipoptblock;
1278 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1280 struct ipoption ipoptblock;
1281 struct ipoption *ipopt = &ipoptblock;
1282 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1285 /* Occasional genuine failures of getsockopt() have been seen - for
1286 example, "reset by peer". Therefore, just log and give up on this
1287 call, unless the error is ENOPROTOOPT. This error is given by systems
1288 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1289 of writing. So for that error, carry on - we just can't do an IP options
1292 DEBUG(D_receive) debug_printf("checking for IP options\n");
1294 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1297 if (errno != ENOPROTOOPT)
1299 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1300 host_and_ident(FALSE), strerror(errno));
1301 smtp_printf("451 SMTP service not available\r\n");
1306 /* Deal with any IP options that are set. On the systems I have looked at,
1307 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1308 more logging data than will fit in big_buffer. Nevertheless, after somebody
1309 questioned this code, I've added in some paranoid checking. */
1311 else if (optlen > 0)
1313 uschar *p = big_buffer;
1314 uschar *pend = big_buffer + big_buffer_size;
1315 uschar *opt, *adptr;
1317 struct in_addr addr;
1320 uschar *optstart = (uschar *)(ipopt->__data);
1322 uschar *optstart = (uschar *)(ipopt->ip_opts);
1324 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1327 DEBUG(D_receive) debug_printf("IP options exist\n");
1329 Ustrcpy(p, "IP options on incoming call:");
1332 for (opt = optstart; opt != NULL &&
1333 opt < (uschar *)(ipopt) + optlen;)
1347 if (!string_format(p, pend-p, " %s [@%s",
1348 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1350 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1352 inet_ntoa(ipopt->ip_dst)))
1354 inet_ntoa(ipopt->ipopt_dst)))
1362 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1364 while (optcount-- > 0)
1366 memcpy(&addr, adptr, sizeof(addr));
1367 if (!string_format(p, pend - p - 1, "%s%s",
1368 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1374 adptr += sizeof(struct in_addr);
1383 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1386 for (i = 0; i < opt[1]; i++)
1388 sprintf(CS p, "%2.2x ", opt[i]);
1399 log_write(0, LOG_MAIN, "%s", big_buffer);
1401 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1403 log_write(0, LOG_MAIN|LOG_REJECT,
1404 "connection from %s refused (IP options)", host_and_ident(FALSE));
1406 smtp_printf("554 SMTP service not available\r\n");
1410 /* Length of options = 0 => there are no options */
1412 else DEBUG(D_receive) debug_printf("no IP options found\n");
1414 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1416 /* Set keep-alive in socket options. The option is on by default. This
1417 setting is an attempt to get rid of some hanging connections that stick in
1418 read() when the remote end (usually a dialup) goes away. */
1420 if (smtp_accept_keepalive && !sender_host_notsocket)
1421 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1423 /* If the current host matches host_lookup, set the name by doing a
1424 reverse lookup. On failure, sender_host_name will be NULL and
1425 host_lookup_failed will be TRUE. This may or may not be serious - optional
1428 if (verify_check_host(&host_lookup) == OK)
1430 (void)host_name_lookup();
1431 host_build_sender_fullhost();
1434 /* Delay this until we have the full name, if it is looked up. */
1436 set_process_info("handling incoming connection from %s",
1437 host_and_ident(FALSE));
1439 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1440 smtps port for use with older style SSL MTAs. */
1443 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1447 /* Test for explicit connection rejection */
1449 if (verify_check_host(&host_reject_connection) == OK)
1451 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1452 "from %s (host_reject_connection)", host_and_ident(FALSE));
1453 smtp_printf("554 SMTP service not available\r\n");
1457 /* Test with TCP Wrappers if so configured */
1459 #ifdef USE_TCP_WRAPPERS
1460 if (!hosts_ctl("exim",
1461 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1462 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1463 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1465 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1466 log_write(L_connection_reject,
1467 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1468 "(tcp wrappers)", host_and_ident(FALSE));
1469 smtp_printf("554 SMTP service not available\r\n");
1474 /* Check for reserved slots. Note that the count value doesn't include
1475 this process, as it gets upped in the parent process. */
1477 if (smtp_accept_max > 0 &&
1478 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1480 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1482 log_write(L_connection_reject,
1483 LOG_MAIN, "temporarily refused connection from %s: not in "
1484 "reserve list: connected=%d max=%d reserve=%d%s",
1485 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1486 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1487 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1488 "please try again later\r\n", smtp_active_hostname);
1491 reserved_host = TRUE;
1494 /* If a load level above which only messages from reserved hosts are
1495 accepted is set, check the load. For incoming calls via the daemon, the
1496 check is done in the superior process if there are no reserved hosts, to
1497 save a fork. In all cases, the load average will already be available
1498 in a global variable at this point. */
1500 if (smtp_load_reserve >= 0 &&
1501 load_average > smtp_load_reserve &&
1503 verify_check_host(&smtp_reserve_hosts) != OK)
1505 log_write(L_connection_reject,
1506 LOG_MAIN, "temporarily refused connection from %s: not in "
1507 "reserve list and load average = %.2f", host_and_ident(FALSE),
1508 (double)load_average/1000.0);
1509 smtp_printf("421 %s: Too much load; please try again later\r\n",
1510 smtp_active_hostname);
1514 /* Determine whether unqualified senders or recipients are permitted
1515 for this host. Unfortunately, we have to do this every time, in order to
1516 set the flags so that they can be inspected when considering qualifying
1517 addresses in the headers. For a site that permits no qualification, this
1518 won't take long, however. */
1520 allow_unqualified_sender =
1521 verify_check_host(&sender_unqualified_hosts) == OK;
1523 allow_unqualified_recipient =
1524 verify_check_host(&recipient_unqualified_hosts) == OK;
1526 /* Determine whether HELO/EHLO is required for this host. The requirement
1527 can be hard or soft. */
1529 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1531 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1533 /* Determine whether this hosts is permitted to send syntactic junk
1534 after a HELO or EHLO command. */
1536 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1539 /* For batch SMTP input we are now done. */
1541 if (smtp_batched_input) return TRUE;
1543 /* Run the ACL if it exists */
1545 if (acl_smtp_connect != NULL)
1548 uschar *user_msg, *log_msg;
1549 smtp_data = US"in \"connect\" ACL"; /* For logged failure message */
1550 rc = acl_check(ACL_WHERE_CONNECT, US"", acl_smtp_connect, &user_msg,
1554 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1559 /* Output the initial message for a two-way SMTP connection. It may contain
1560 newlines, which then cause a multi-line response to be given. */
1562 s = expand_string(smtp_banner);
1564 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1565 "failed: %s", smtp_banner, expand_string_message);
1567 /* Remove any terminating newlines; might as well remove trailing space too */
1570 while (p > s && isspace(p[-1])) p--;
1573 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1574 is all contained in a single IP packet. The original code wrote out the
1575 greeting using several calls to fprint/fputc, and on busy servers this could
1576 cause it to be split over more than one packet - which caused CC:Mail to fall
1577 over when it got the second part of the greeting after sending its first
1578 command. Sigh. To try to avoid this, build the complete greeting message
1579 first, and output it in one fell swoop. This gives a better chance of it
1580 ending up as a single packet. */
1582 ss = store_get(size);
1586 do /* At least once, in case we have an empty string */
1589 uschar *linebreak = Ustrchr(p, '\n');
1590 if (linebreak == NULL)
1593 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1597 len = linebreak - p;
1598 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1600 ss = string_cat(ss, &size, &ptr, p, len);
1601 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1603 if (linebreak != NULL) p++;
1607 ss[ptr] = 0; /* string_cat leaves room for this */
1609 /* Before we write the banner, check that there is no input pending, unless
1610 this synchronisation check is disabled. */
1612 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1615 struct timeval tzero;
1619 FD_SET(fileno(smtp_in), &fds);
1620 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1623 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1626 if (rc > 150) rc = 150;
1627 smtp_inbuffer[rc] = 0;
1628 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: "
1629 "synchronization error (input sent without waiting for greeting): "
1630 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1631 string_printing(smtp_inbuffer));
1632 smtp_printf("554 SMTP synchronization error\r\n");
1638 /* Now output the banner */
1640 smtp_printf("%s", ss);
1648 /*************************************************
1649 * Handle SMTP syntax and protocol errors *
1650 *************************************************/
1652 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1653 to do so. Then transmit the error response. The return value depends on the
1654 number of syntax and protocol errors in this SMTP session.
1657 type error type, given as a log flag bit
1658 code response code; <= 0 means don't send a response
1659 data data to reflect in the response (can be NULL)
1660 errmess the error message
1662 Returns: -1 limit of syntax/protocol errors NOT exceeded
1663 +1 limit of syntax/protocol errors IS exceeded
1665 These values fit in with the values of the "done" variable in the main
1666 processing loop in smtp_setup_msg(). */
1669 synprot_error(int type, int code, uschar *data, uschar *errmess)
1673 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1674 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1675 string_printing(cmd_buffer), host_and_ident(TRUE), errmess);
1677 if (++synprot_error_count > smtp_max_synprot_errors)
1680 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1681 "syntax or protocol errors (last command was \"%s\")",
1682 host_and_ident(FALSE), cmd_buffer);
1687 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1688 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1690 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1699 /*************************************************
1700 * Log incomplete transactions *
1701 *************************************************/
1703 /* This function is called after a transaction has been aborted by RSET, QUIT,
1704 connection drops or other errors. It logs the envelope information received
1705 so far in order to preserve address verification attempts.
1707 Argument: string to indicate what aborted the transaction
1712 incomplete_transaction_log(uschar *what)
1714 if (sender_address == NULL || /* No transaction in progress */
1715 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1718 /* Build list of recipients for logging */
1720 if (recipients_count > 0)
1723 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1724 for (i = 0; i < recipients_count; i++)
1725 raw_recipients[i] = recipients_list[i].address;
1726 raw_recipients_count = recipients_count;
1729 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1730 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1736 /*************************************************
1737 * Send SMTP response, possibly multiline *
1738 *************************************************/
1740 /* There are, it seems, broken clients out there that cannot handle multiline
1741 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1742 output nothing for non-final calls, and only the first line for anything else.
1746 final FALSE if the last line isn't the final line
1747 msg message text, possibly containing newlines
1753 smtp_respond(int code, BOOL final, uschar *msg)
1755 if (!final && no_multiline_responses) return;
1759 uschar *nl = Ustrchr(msg, '\n');
1762 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1765 else if (nl[1] == 0 || no_multiline_responses)
1767 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1772 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1774 while (isspace(*msg)) msg++;
1782 /*************************************************
1783 * Handle an ACL failure *
1784 *************************************************/
1786 /* This function is called when acl_check() fails. As well as calls from within
1787 this module, it is called from receive.c for an ACL after DATA. It sorts out
1788 logging the incident, and sets up the error response. A message containing
1789 newlines is turned into a multiline SMTP response, but for logging, only the
1792 There's a table of the response codes to use in globals.c, along with the table
1793 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1794 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1795 that the response should be 252 in the disabled state, because there are broken
1796 clients that try VRFY before RCPT. A 5xx response should be given only when the
1797 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1798 given on refusal, and for AUTH, 503.
1801 where where the ACL was called from
1803 user_msg a message that can be included in an SMTP response
1804 log_msg a message for logging
1806 Returns: 0 in most cases
1807 2 if the failure code was FAIL_DROP, in which case the
1808 SMTP connection should be dropped (this value fits with the
1809 "done" variable in smtp_setup_msg() below)
1813 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1815 int code = acl_wherecodes[where];
1816 BOOL drop = rc == FAIL_DROP;
1818 uschar *sender_info = US"";
1819 uschar *what = (where == ACL_WHERE_PREDATA)? US"DATA" :
1820 #ifdef WITH_CONTENT_SCAN
1821 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1823 (where == ACL_WHERE_DATA)? US"after DATA" :
1824 string_sprintf("%s %s", acl_wherenames[where], smtp_data);
1826 if (drop) rc = FAIL;
1828 /* We used to have sender_address here; however, there was a bug that was not
1829 updating sender_address after a rewrite during a verify. When this bug was
1830 fixed, sender_address at this point became the rewritten address. I'm not sure
1831 this is what should be logged, so I've changed to logging the unrewritten
1832 address to retain backward compatibility. */
1834 #ifndef WITH_CONTENT_SCAN
1835 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1837 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1840 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1841 sender_address_unrewritten : sender_address);
1844 /* If there's been a sender verification failure with a specific message, and
1845 we have not sent a response about it yet, do so now, as a preliminary line for
1846 failures, but not defers. However, log it in both cases. */
1848 if (sender_verified_failed != NULL &&
1849 !testflag(sender_verified_failed, af_sverify_told))
1851 setflag(sender_verified_failed, af_sverify_told);
1853 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1854 host_and_ident(TRUE),
1855 ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail",
1856 sender_verified_failed->address,
1857 (sender_verified_failed->message == NULL)? US"" :
1858 string_sprintf(": %s", sender_verified_failed->message));
1860 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1861 smtp_respond(code, FALSE, string_sprintf(
1862 testflag(sender_verified_failed, af_verify_pmfail)?
1863 "Postmaster verification failed while checking <%s>\n%s\n"
1864 "Several RFCs state that you are required to have a postmaster\n"
1865 "mailbox for each mail domain. This host does not accept mail\n"
1866 "from domains whose servers reject the postmaster address."
1868 testflag(sender_verified_failed, af_verify_nsfail)?
1869 "Callback setup failed while verifying <%s>\n%s\n"
1870 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1871 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1872 "RFC requirements, and stops you from receiving standard bounce\n"
1873 "messages. This host does not accept mail from domains whose servers\n"
1876 "Verification failed for <%s>\n%s",
1877 sender_verified_failed->address,
1878 sender_verified_failed->user_message));
1881 /* Sort out text for logging */
1883 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1884 lognl = Ustrchr(log_msg, '\n');
1885 if (lognl != NULL) *lognl = 0;
1887 /* Send permanent failure response to the command, but the code used isn't
1888 always a 5xx one - see comments at the start of this function. If the original
1889 rc was FAIL_DROP we drop the connection and yield 2. */
1891 if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1892 US"Administrative prohibition" : user_msg);
1894 /* Send temporary failure response to the command. Don't give any details,
1895 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1896 verb, and for a header verify when smtp_return_error_details is set.
1898 This conditional logic is all somewhat of a mess because of the odd
1899 interactions between temp_details and return_error_details. One day it should
1900 be re-implemented in a tidier fashion. */
1904 if (acl_temp_details && user_msg != NULL)
1906 if (smtp_return_error_details &&
1907 sender_verified_failed != NULL &&
1908 sender_verified_failed->message != NULL)
1910 smtp_respond(451, FALSE, sender_verified_failed->message);
1912 smtp_respond(451, TRUE, user_msg);
1915 smtp_printf("451 Temporary local problem - please try later\r\n");
1918 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
1919 Otherwise, log why it is closing if required and return 2. */
1921 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1922 host_and_ident(TRUE),
1923 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1925 if (!drop) return 0;
1927 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1928 smtp_get_connection_info());
1935 /*************************************************
1936 * Initialize for SMTP incoming message *
1937 *************************************************/
1939 /* This function conducts the initial dialogue at the start of an incoming SMTP
1940 message, and builds a list of recipients. However, if the incoming message
1941 is part of a batch (-bS option) a separate function is called since it would
1942 be messy having tests splattered about all over this function. This function
1943 therefore handles the case where interaction is occurring. The input and output
1944 files are set up in smtp_in and smtp_out.
1946 The global recipients_list is set to point to a vector of recipient_item
1947 blocks, whose number is given by recipients_count. This is extended by the
1948 receive_add_recipient() function. The global variable sender_address is set to
1949 the sender's address. The yield is +1 if a message has been successfully
1950 started, 0 if a QUIT command was encountered or the connection was refused from
1951 the particular host, or -1 if the connection was lost.
1955 Returns: > 0 message successfully started (reached DATA)
1956 = 0 QUIT read or end of file reached or call refused
1961 smtp_setup_msg(void)
1964 BOOL toomany = FALSE;
1965 BOOL discarded = FALSE;
1966 BOOL last_was_rej_mail = FALSE;
1967 BOOL last_was_rcpt = FALSE;
1968 void *reset_point = store_get(0);
1970 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
1972 /* Reset for start of new message. We allow one RSET not to be counted as a
1973 nonmail command, for those MTAs that insist on sending it between every
1974 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
1975 TLS between messages (an Exim client may do this if it has messages queued up
1976 for the host). Note: we do NOT reset AUTH at this point. */
1978 smtp_reset(reset_point);
1979 message_ended = END_NOTSTARTED;
1981 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
1982 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
1983 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
1985 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
1988 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
1990 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
1992 /* Batched SMTP is handled in a different function. */
1994 if (smtp_batched_input) return smtp_setup_batch_msg();
1996 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1997 value. The values are 2 larger than the required yield of the function. */
2002 uschar *etrn_command;
2003 uschar *etrn_serialize_key;
2005 uschar *user_msg, *log_msg;
2006 uschar *recipient = NULL;
2007 uschar *hello = NULL;
2008 uschar *set_id = NULL;
2010 BOOL was_rej_mail = FALSE;
2011 BOOL was_rcpt = FALSE;
2012 void (*oldsignal)(int);
2014 int start, end, sender_domain, recipient_domain;
2019 switch(smtp_read_command(TRUE))
2021 /* The AUTH command is not permitted to occur inside a transaction, and may
2022 occur successfully only once per connection, and then only when we've
2023 advertised it. Actually, that isn't quite true. When TLS is started, all
2024 previous information about a connection must be discarded, so a new AUTH is
2025 permitted at that time.
2027 AUTH is initially labelled as a "nonmail command" so that one occurrence
2028 doesn't get counted. We change the label here so that multiple failing
2029 AUTHS will eventually hit the nonmail threshold. */
2032 authentication_failed = TRUE;
2033 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2035 if (!auth_advertised)
2037 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2038 US"AUTH command used when not advertised");
2041 if (sender_host_authenticated != NULL)
2043 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2044 US"already authenticated");
2047 if (sender_address != NULL)
2049 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2050 US"not permitted in mail transaction");
2056 if (acl_smtp_auth != NULL)
2058 rc = acl_check(ACL_WHERE_AUTH, smtp_data, acl_smtp_auth, &user_msg,
2062 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2067 /* Find the name of the requested authentication mechanism. */
2070 while ((c = *smtp_data) != 0 && !isspace(c))
2072 if (!isalnum(c) && c != '-' && c != '_')
2074 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2075 US"invalid character in authentication mechanism name");
2081 /* If not at the end of the line, we must be at white space. Terminate the
2082 name and move the pointer on to any data that may be present. */
2084 if (*smtp_data != 0)
2087 while (isspace(*smtp_data)) smtp_data++;
2090 /* Search for an authentication mechanism which is configured for use
2091 as a server and which has been advertised. */
2093 for (au = auths; au != NULL; au = au->next)
2095 if (strcmpic(s, au->public_name) == 0 && au->server &&
2096 au->advertised) break;
2101 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2102 string_sprintf("%s authentication mechanism not supported", s));
2106 /* Run the checking code, passing the remainder of the command
2107 line as data. Initialize $0 empty. The authenticator may set up
2108 other numeric variables. Afterwards, have a go at expanding the set_id
2109 string, even if authentication failed - for bad passwords it can be useful
2110 to log the userid. On success, require set_id to expand and exist, and
2111 put it in authenticated_id. Save this in permanent store, as the working
2112 store gets reset at HELO, RSET, etc. */
2115 expand_nlength[0] = 0; /* $0 contains nothing */
2117 c = (au->info->servercode)(au, smtp_data);
2118 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2119 expand_nmax = -1; /* Reset numeric variables */
2121 /* The value of authenticated_id is stored in the spool file and printed in
2122 log lines. It must not contain binary zeros or newline characters. In
2123 normal use, it never will, but when playing around or testing, this error
2124 can (did) happen. To guard against this, ensure that the id contains only
2125 printing characters. */
2127 if (set_id != NULL) set_id = string_printing(set_id);
2129 /* For the non-OK cases, set up additional logging data if set_id
2134 if (set_id != NULL && *set_id != 0)
2135 set_id = string_sprintf(" (set_id=%s)", set_id);
2139 /* Switch on the result */
2144 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2146 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2147 sender_host_authenticated = au->name;
2148 authentication_failed = FALSE;
2150 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2151 ((sender_host_address != NULL)? pnlocal : 0);
2152 s = ss = US"235 Authentication succeeded";
2153 authenticated_by = au;
2157 /* Authentication succeeded, but we failed to expand the set_id string.
2158 Treat this as a temporary error. */
2160 auth_defer_msg = expand_string_message;
2164 s = string_sprintf("435 Unable to authenticate at present%s",
2165 auth_defer_user_msg);
2166 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2167 set_id, auth_defer_msg);
2171 s = ss = US"501 Invalid base64 data";
2175 s = ss = US"501 Authentication cancelled";
2179 s = ss = US"553 Initial data not expected";
2183 s = US"535 Incorrect authentication data";
2184 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2188 s = US"435 Internal error";
2189 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2190 "check", set_id, c);
2194 smtp_printf("%s\r\n", s);
2196 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2197 au->name, host_and_ident(FALSE), ss);
2199 break; /* AUTH_CMD */
2201 /* The HELO/EHLO commands are permitted to appear in the middle of a
2202 session as well as at the beginning. They have the effect of a reset in
2203 addition to their other functions. Their absence at the start cannot be
2204 taken to be an error.
2208 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2209 or 502 failure replies MUST be returned as appropriate. The SMTP
2210 server MUST stay in the same state after transmitting these replies
2211 that it was in before the EHLO was received.
2213 Therefore, we do not do the reset until after checking the command for
2214 acceptability. This change was made for Exim release 4.11. Previously
2215 it did the reset first. */
2226 HELO_EHLO: /* Common code for HELO and EHLO */
2227 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2228 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2230 /* Reject the HELO if its argument was invalid or non-existent. A
2231 successful check causes the argument to be saved in malloc store. */
2233 if (!check_helo(smtp_data))
2235 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2237 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2238 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2239 (*smtp_data == 0)? US"(no argument given)" :
2240 string_printing(smtp_data));
2242 if (++synprot_error_count > smtp_max_synprot_errors)
2244 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2245 "syntax or protocol errors (last command was \"%s\")",
2246 host_and_ident(FALSE), cmd_buffer);
2253 /* If sender_host_unknown is true, we have got here via the -bs interface,
2254 not called from inetd. Otherwise, we are running an IP connection and the
2255 host address will be set. If the helo name is the primary name of this
2256 host and we haven't done a reverse lookup, force one now. If helo_required
2257 is set, ensure that the HELO name matches the actual host. If helo_verify
2258 is set, do the same check, but softly. */
2260 if (!sender_host_unknown)
2262 BOOL old_helo_verified = helo_verified;
2263 uschar *p = smtp_data;
2265 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2268 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2269 because otherwise the log can be confusing. */
2271 if (sender_host_name == NULL &&
2272 (deliver_domain = sender_helo_name, /* set $domain */
2273 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2274 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2275 (void)host_name_lookup();
2277 /* Rebuild the fullhost info to include the HELO name (and the real name
2278 if it was looked up.) */
2280 host_build_sender_fullhost(); /* Rebuild */
2281 set_process_info("handling%s incoming connection from %s",
2282 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2284 /* Verify if configured. This doesn't give much security, but it does
2285 make some people happy to be able to do it. Note that HELO is legitimately
2286 allowed to quote an address literal. Allow for IPv6 ::ffff: literals. */
2288 helo_verified = FALSE;
2289 if (helo_required || helo_verify)
2291 BOOL tempfail = FALSE;
2293 HDEBUG(D_receive) debug_printf("verifying %s %s\n", hello,
2295 if (sender_helo_name[0] == '[')
2297 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2298 Ustrlen(sender_host_address)) == 0;
2303 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2304 helo_verified = Ustrncmp(sender_helo_name + 1,
2305 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2310 { if (helo_verified) debug_printf("matched host address\n"); }
2313 /* Do a reverse lookup if one hasn't already given a positive or
2314 negative response. If that fails, or the name doesn't match, try
2315 checking with a forward lookup. */
2319 if (sender_host_name == NULL && !host_lookup_failed)
2320 tempfail = host_name_lookup() == DEFER;
2322 /* If a host name is known, check it and all its aliases. */
2324 if (sender_host_name != NULL)
2326 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2330 HDEBUG(D_receive) debug_printf("matched host name\n");
2334 uschar **aliases = sender_host_aliases;
2335 while (*aliases != NULL)
2337 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2338 if (helo_verified) break;
2343 debug_printf("matched alias %s\n", *(--aliases));
2348 /* Final attempt: try a forward lookup of the helo name */
2354 h.name = sender_helo_name;
2358 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2360 rc = host_find_byname(&h, NULL, NULL, TRUE);
2361 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2366 if (Ustrcmp(hh->address, sender_host_address) == 0)
2368 helo_verified = TRUE;
2370 debug_printf("IP address for %s matches calling address\n",
2380 /* Verification failed. A temporary lookup failure gives a temporary
2387 smtp_printf("%d %s argument does not match calling host\r\n",
2388 tempfail? 451 : 550, hello);
2389 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2390 tempfail? "temporarily " : "",
2391 hello, sender_helo_name, host_and_ident(FALSE));
2392 helo_verified = old_helo_verified;
2393 break; /* End of HELO/EHLO processing */
2395 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2396 "helo_try_verify_hosts\n", hello);
2401 #ifdef EXPERIMENTAL_SPF
2402 /* set up SPF context */
2403 spf_init(sender_helo_name, sender_host_address);
2406 /* Apply an ACL check if one is defined */
2408 if (acl_smtp_helo != NULL)
2410 rc = acl_check(ACL_WHERE_HELO, smtp_data, acl_smtp_helo, &user_msg,
2414 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2415 sender_helo_name = NULL;
2416 host_build_sender_fullhost(); /* Rebuild */
2421 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2422 abandoning any previous message. */
2424 received_protocol = (esmtp?
2426 ((sender_host_authenticated != NULL)? pauthed : 0) +
2427 ((tls_active >= 0)? pcrpted : 0)]
2429 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2431 ((sender_host_address != NULL)? pnlocal : 0);
2433 smtp_reset(reset_point);
2436 /* Generate an OK reply, including the ident if present, and also
2437 the IP address if present. Reflecting back the ident is intended
2438 as a deterrent to mail forgers. For maximum efficiency, and also
2439 because some broken systems expect each response to be in a single
2440 packet, arrange that it is sent in one write(). */
2442 auth_advertised = FALSE;
2443 pipelining_advertised = FALSE;
2445 tls_advertised = FALSE;
2448 s = string_sprintf("250 %s Hello %s%s%s",
2449 smtp_active_hostname,
2450 (sender_ident == NULL)? US"" : sender_ident,
2451 (sender_ident == NULL)? US"" : US" at ",
2452 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2457 if (sender_host_address != NULL)
2459 s = string_cat(s, &size, &ptr, US" [", 2);
2460 s = string_cat(s, &size, &ptr, sender_host_address,
2461 Ustrlen(sender_host_address));
2462 s = string_cat(s, &size, &ptr, US"]", 1);
2465 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2467 /* If we received EHLO, we must create a multiline response which includes
2468 the functions supported. */
2474 /* I'm not entirely happy with this, as an MTA is supposed to check
2475 that it has enough room to accept a message of maximum size before
2476 it sends this. However, there seems little point in not sending it.
2477 The actual size check happens later at MAIL FROM time. By postponing it
2478 till then, VRFY and EXPN can be used after EHLO when space is short. */
2480 if (thismessage_size_limit > 0)
2482 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2483 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2487 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2490 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2491 clean; if it has an 8-bit character in its hand, it just sends it. It
2492 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2493 However, some users want this option simply in order to stop MUAs
2494 mangling messages that contain top-bit-set characters. It is therefore
2495 provided as an option. */
2497 if (accept_8bitmime)
2498 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2500 /* Advertise ETRN if there's an ACL checking whether a host is
2501 permitted to issue it; a check is made when any host actually tries. */
2503 if (acl_smtp_etrn != NULL)
2505 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2508 /* Advertise EXPN if there's an ACL checking whether a host is
2509 permitted to issue it; a check is made when any host actually tries. */
2511 if (acl_smtp_expn != NULL)
2513 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2516 /* Exim is quite happy with pipelining, so let the other end know that
2517 it is safe to use it, unless advertising is disabled. */
2519 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2521 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2522 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2523 pipelining_advertised = TRUE;
2526 /* If any server authentication mechanisms are configured, advertise
2527 them if the current host is in auth_advertise_hosts. The problem with
2528 advertising always is that some clients then require users to
2529 authenticate (and aren't configurable otherwise) even though it may not
2530 be necessary (e.g. if the host is in host_accept_relay).
2532 RFC 2222 states that SASL mechanism names contain only upper case
2533 letters, so output the names in upper case, though we actually recognize
2534 them in either case in the AUTH command. */
2538 if (verify_check_host(&auth_advertise_hosts) == OK)
2542 for (au = auths; au != NULL; au = au->next)
2544 if (au->server && (au->advertise_condition == NULL ||
2545 expand_check_condition(au->advertise_condition, au->name,
2546 US"authenticator")))
2551 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2553 auth_advertised = TRUE;
2556 s = string_cat(s, &size, &ptr, US" ", 1);
2557 s = string_cat(s, &size, &ptr, au->public_name,
2558 Ustrlen(au->public_name));
2559 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2560 au->advertised = TRUE;
2562 else au->advertised = FALSE;
2564 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2568 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2569 if it has been included in the binary, and the host matches
2570 tls_advertise_hosts. We must *not* advertise if we are already in a
2571 secure connection. */
2574 if (tls_active < 0 &&
2575 verify_check_host(&tls_advertise_hosts) != FAIL)
2577 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2578 tls_advertised = TRUE;
2582 /* Finish off the multiline reply with one that is always available. */
2584 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2587 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2593 if (tls_active >= 0) (void)tls_write(s, ptr); else
2596 fwrite(s, 1, ptr, smtp_out);
2597 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2599 break; /* HELO/EHLO */
2602 /* The MAIL command requires an address as an operand. All we do
2603 here is to parse it for syntactic correctness. The form "<>" is
2604 a special case which converts into an empty string. The start/end
2605 pointers in the original are not used further for this address, as
2606 it is the canonical extracted address which is all that is kept. */
2609 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2610 was_rej_mail = TRUE; /* Reset if accepted */
2612 if (helo_required && !helo_seen)
2614 smtp_printf("503 HELO or EHLO required\r\n");
2615 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2616 "HELO/EHLO given", host_and_ident(FALSE));
2620 if (sender_address != NULL)
2622 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2623 US"sender already given");
2627 if (smtp_data[0] == 0)
2629 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2630 US"MAIL must have an address operand");
2634 /* Check to see if the limit for messages per connection would be
2635 exceeded by accepting further messages. */
2637 if (smtp_accept_max_per_connection > 0 &&
2638 smtp_mailcmd_count > smtp_accept_max_per_connection)
2640 smtp_printf("421 too many messages in this connection\r\n");
2641 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2642 "messages in one connection", host_and_ident(TRUE));
2646 /* Reset for start of message - even if this is going to fail, we
2647 obviously need to throw away any previous data. */
2649 smtp_reset(reset_point);
2651 sender_data = recipient_data = NULL;
2653 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2657 uschar *name, *value, *end;
2658 unsigned long int size;
2660 if (!extract_option(&name, &value)) break;
2662 /* Handle SIZE= by reading the value. We don't do the check till later,
2663 in order to be able to log the sender address on failure. */
2665 if (strcmpic(name, US"SIZE") == 0 &&
2666 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2668 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2670 message_size = (int)size;
2673 /* If this session was initiated with EHLO and accept_8bitmime is set,
2674 Exim will have indicated that it supports the BODY=8BITMIME option. In
2675 fact, it does not support this according to the RFCs, in that it does not
2676 take any special action for forwarding messages containing 8-bit
2677 characters. That is why accept_8bitmime is not the default setting, but
2678 some sites want the action that is provided. We recognize both "8BITMIME"
2679 and "7BIT" as body types, but take no action. */
2681 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2682 (strcmpic(value, US"8BITMIME") == 0 ||
2683 strcmpic(value, US"7BIT") == 0)) {}
2685 /* Handle the AUTH extension. If the value given is not "<>" and either
2686 the ACL says "yes" or there is no ACL but the sending host is
2687 authenticated, we set it up as the authenticated sender. However, if the
2688 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2689 the condition is met. The value of AUTH is an xtext, which means that +,
2690 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2693 else if (strcmpic(name, US"AUTH") == 0)
2695 if (Ustrcmp(value, "<>") != 0)
2700 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2702 /* Put back terminator overrides for error message */
2705 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2706 US"invalid data for AUTH");
2710 if (acl_smtp_mailauth == NULL)
2712 ignore_msg = US"client not authenticated";
2713 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2717 ignore_msg = US"rejected by ACL";
2718 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2719 &user_msg, &log_msg);
2725 if (authenticated_by == NULL ||
2726 authenticated_by->mail_auth_condition == NULL ||
2727 expand_check_condition(authenticated_by->mail_auth_condition,
2728 authenticated_by->name, US"authenticator"))
2729 break; /* Accept the AUTH */
2731 ignore_msg = US"server_mail_auth_condition failed";
2732 if (authenticated_id != NULL)
2733 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2734 ignore_msg, authenticated_id);
2739 authenticated_sender = NULL;
2740 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2741 value, host_and_ident(TRUE), ignore_msg);
2744 /* Should only get DEFER or ERROR here. Put back terminator
2745 overrides for error message */
2750 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2757 /* Unknown option. Stick back the terminator characters and break
2758 the loop. An error for a malformed address will occur. */
2768 /* If we have passed the threshold for rate limiting, apply the current
2769 delay, and update it for next time, provided this is a limited host. */
2771 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2772 verify_check_host(&smtp_ratelimit_hosts) == OK)
2774 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2775 smtp_delay_mail/1000.0);
2776 millisleep((int)smtp_delay_mail);
2777 smtp_delay_mail *= smtp_rlm_factor;
2778 if (smtp_delay_mail > (double)smtp_rlm_limit)
2779 smtp_delay_mail = (double)smtp_rlm_limit;
2782 /* Now extract the address, first applying any SMTP-time rewriting. The
2783 TRUE flag allows "<>" as a sender address. */
2785 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2786 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2787 global_rewrite_rules) : smtp_data;
2789 /* rfc821_domains = TRUE; << no longer needed */
2791 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2793 /* rfc821_domains = FALSE; << no longer needed */
2795 if (raw_sender == NULL)
2797 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2801 sender_address = raw_sender;
2803 /* If there is a configured size limit for mail, check that this message
2804 doesn't exceed it. The check is postponed to this point so that the sender
2807 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2809 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2810 log_write(L_size_reject,
2811 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2812 "message too big: size%s=%d max=%d",
2814 host_and_ident(TRUE),
2815 (message_size == INT_MAX)? ">" : "",
2817 thismessage_size_limit);
2818 sender_address = NULL;
2822 /* Check there is enough space on the disk unless configured not to.
2823 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2824 plus the current message - i.e. we accept the message only if it won't
2825 reduce the space below the threshold. Add 5000 to the size to allow for
2826 overheads such as the Received: line and storing of recipients, etc.
2827 By putting the check here, even when SIZE is not given, it allow VRFY
2828 and EXPN etc. to be used when space is short. */
2830 if (!receive_check_fs(
2831 (smtp_check_spool_space && message_size >= 0)?
2832 message_size + 5000 : 0))
2834 smtp_printf("452 Space shortage, please try later\r\n");
2835 sender_address = NULL;
2839 /* If sender_address is unqualified, reject it, unless this is a locally
2840 generated message, or the sending host or net is permitted to send
2841 unqualified addresses - typically local machines behaving as MUAs -
2842 in which case just qualify the address. The flag is set above at the start
2843 of the SMTP connection. */
2845 if (sender_domain == 0 && sender_address[0] != 0)
2847 if (allow_unqualified_sender)
2849 sender_domain = Ustrlen(sender_address) + 1;
2850 sender_address = rewrite_address_qualify(sender_address, FALSE);
2851 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2856 smtp_printf("501 %s: sender address must contain a domain\r\n",
2858 log_write(L_smtp_syntax_error,
2859 LOG_MAIN|LOG_REJECT,
2860 "unqualified sender rejected: <%s> %s%s",
2862 host_and_ident(TRUE),
2864 sender_address = NULL;
2869 /* Apply an ACL check if one is defined, before responding */
2871 rc = (acl_smtp_mail == NULL)? OK :
2872 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2874 if (rc == OK || rc == DISCARD)
2876 smtp_printf("250 OK\r\n");
2877 smtp_delay_rcpt = smtp_rlr_base;
2878 recipients_discarded = (rc == DISCARD);
2879 was_rej_mail = FALSE;
2884 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2885 sender_address = NULL;
2890 /* The RCPT command requires an address as an operand. All we do
2891 here is to parse it for syntactic correctness. There may be any number
2892 of RCPT commands, specifying multiple senders. We build them all into
2893 a data structure that is in argc/argv format. The start/end values
2894 given by parse_extract_address are not used, as we keep only the
2895 extracted address. */
2901 /* There must be a sender address; if the sender was rejected and
2902 pipelining was advertised, we assume the client was pipelining, and do not
2903 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2904 get the same treatment. */
2906 if (sender_address == NULL)
2908 if (pipelining_advertised && last_was_rej_mail)
2910 smtp_printf("503 sender not yet given\r\n");
2911 was_rej_mail = TRUE;
2915 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2916 US"sender not yet given");
2917 was_rcpt = FALSE; /* Not a valid RCPT */
2923 /* Check for an operand */
2925 if (smtp_data[0] == 0)
2927 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2928 US"RCPT must have an address operand");
2933 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2934 as a recipient address */
2936 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2937 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2938 global_rewrite_rules) : smtp_data;
2940 /* rfc821_domains = TRUE; << no longer needed */
2941 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2942 &recipient_domain, FALSE);
2943 /* rfc821_domains = FALSE; << no longer needed */
2945 if (recipient == NULL)
2947 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2952 /* If the recipient address is unqualified, reject it, unless this is a
2953 locally generated message. However, unqualified addresses are permitted
2954 from a configured list of hosts and nets - typically when behaving as
2955 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2956 really. The flag is set at the start of the SMTP connection.
2958 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2959 assumed this meant "reserved local part", but the revision of RFC 821 and
2960 friends now makes it absolutely clear that it means *mailbox*. Consequently
2961 we must always qualify this address, regardless. */
2963 if (recipient_domain == 0)
2965 if (allow_unqualified_recipient ||
2966 strcmpic(recipient, US"postmaster") == 0)
2968 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2970 recipient_domain = Ustrlen(recipient) + 1;
2971 recipient = rewrite_address_qualify(recipient, TRUE);
2976 smtp_printf("501 %s: recipient address must contain a domain\r\n",
2978 log_write(L_smtp_syntax_error,
2979 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
2980 "<%s> %s%s", recipient, host_and_ident(TRUE),
2986 /* Check maximum allowed */
2988 if (rcpt_count > recipients_max && recipients_max > 0)
2990 if (recipients_max_reject)
2993 smtp_printf("552 too many recipients\r\n");
2995 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
2996 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3001 smtp_printf("452 too many recipients\r\n");
3003 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3004 "temporarily rejected: sender=<%s> %s", sender_address,
3005 host_and_ident(TRUE));
3012 /* If we have passed the threshold for rate limiting, apply the current
3013 delay, and update it for next time, provided this is a limited host. */
3015 if (rcpt_count > smtp_rlr_threshold &&
3016 verify_check_host(&smtp_ratelimit_hosts) == OK)
3018 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3019 smtp_delay_rcpt/1000.0);
3020 millisleep((int)smtp_delay_rcpt);
3021 smtp_delay_rcpt *= smtp_rlr_factor;
3022 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3023 smtp_delay_rcpt = (double)smtp_rlr_limit;
3026 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3027 for them. Otherwise, check the access control list for this recipient. */
3029 rc = recipients_discarded? DISCARD :
3030 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3032 /* The ACL was happy */
3036 smtp_printf("250 Accepted\r\n");
3037 receive_add_recipient(recipient, -1);
3040 /* The recipient was discarded */
3042 else if (rc == DISCARD)
3044 smtp_printf("250 Accepted\r\n");
3047 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3048 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3049 (sender_address_unrewritten != NULL)?
3050 sender_address_unrewritten : sender_address,
3051 smtp_data, recipients_discarded? "MAIL" : "RCPT",
3052 (log_msg == NULL)? US"" : US": ",
3053 (log_msg == NULL)? US"" : log_msg);
3056 /* Either the ACL failed the address, or it was deferred. */
3060 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3061 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3066 /* The DATA command is legal only if it follows successful MAIL FROM
3067 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3068 not counted as a protocol error if it follows RCPT (which must have been
3069 rejected if there are no recipients.) This function is complete when a
3070 valid DATA command is encountered.
3072 Note concerning the code used: RFC 2821 says this:
3074 - If there was no MAIL, or no RCPT, command, or all such commands
3075 were rejected, the server MAY return a "command out of sequence"
3076 (503) or "no valid recipients" (554) reply in response to the
3079 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3080 because it is the same whether pipelining is in use or not. */
3083 if (!discarded && recipients_count <= 0)
3085 if (pipelining_advertised && last_was_rcpt)
3086 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3088 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3089 US"valid RCPT command must precede DATA");
3093 if (toomany && recipients_max_reject)
3095 sender_address = NULL; /* This will allow a new MAIL without RSET */
3096 sender_address_unrewritten = NULL;
3097 smtp_printf("554 Too many recipients\r\n");
3101 if (acl_smtp_predata == NULL) rc = OK; else
3103 enable_dollar_recipients = TRUE;
3104 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3106 enable_dollar_recipients = FALSE;
3111 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3113 message_ended = END_NOTENDED; /* Indicate in middle of data */
3116 /* Either the ACL failed the address, or it was deferred. */
3119 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3125 rc = acl_check(ACL_WHERE_VRFY, smtp_data, acl_smtp_vrfy, &user_msg,
3128 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3134 /* rfc821_domains = TRUE; << no longer needed */
3135 address = parse_extract_address(smtp_data, &errmess, &start, &end,
3136 &recipient_domain, FALSE);
3137 /* rfc821_domains = FALSE; << no longer needed */
3139 if (address == NULL)
3140 s = string_sprintf("501 %s", errmess);
3143 address_item *addr = deliver_make_addr(address, FALSE);
3144 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3145 -1, -1, NULL, NULL, NULL))
3148 s = string_sprintf("250 <%s> is deliverable", address);
3152 s = (addr->message != NULL)?
3153 string_sprintf("451 <%s> %s", address, addr->message) :
3154 string_sprintf("451 Cannot resolve <%s> at this time", address);
3158 s = (addr->message != NULL)?
3159 string_sprintf("550 <%s> %s", address, addr->message) :
3160 string_sprintf("550 <%s> is not deliverable", address);
3161 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3162 smtp_data, host_and_ident(TRUE));
3167 smtp_printf("%s\r\n", s);
3173 rc = acl_check(ACL_WHERE_EXPN, smtp_data, acl_smtp_expn, &user_msg,
3176 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3179 BOOL save_log_testing_mode = log_testing_mode;
3180 address_test_mode = log_testing_mode = TRUE;
3181 (void) verify_address(deliver_make_addr(smtp_data, FALSE), smtp_out,
3182 vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1, NULL, NULL,
3184 address_test_mode = FALSE;
3185 log_testing_mode = save_log_testing_mode; /* true for -bh */
3193 if (!tls_advertised)
3195 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3196 US"STARTTLS command used when not advertised");
3200 /* Apply an ACL check if one is defined */
3202 if (acl_smtp_starttls != NULL)
3204 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3208 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3213 /* RFC 2487 is not clear on when this command may be sent, though it
3214 does state that all information previously obtained from the client
3215 must be discarded if a TLS session is started. It seems reasonble to
3216 do an implied RSET when STARTTLS is received. */
3218 incomplete_transaction_log(US"STARTTLS");
3219 smtp_reset(reset_point);
3221 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3223 /* Attempt to start up a TLS session, and if successful, discard all
3224 knowledge that was obtained previously. At least, that's what the RFC says,
3225 and that's what happens by default. However, in order to work round YAEB,
3226 there is an option to remember the esmtp state. Sigh.
3228 We must allow for an extra EHLO command and an extra AUTH command after
3229 STARTTLS that don't add to the nonmail command count. */
3231 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3233 if (!tls_remember_esmtp)
3234 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3235 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3236 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3237 if (sender_helo_name != NULL)
3239 store_free(sender_helo_name);
3240 sender_helo_name = NULL;
3241 host_build_sender_fullhost(); /* Rebuild */
3242 set_process_info("handling incoming TLS connection from %s",
3243 host_and_ident(FALSE));
3245 received_protocol = (esmtp?
3246 protocols[pextend + pcrpted +
3247 ((sender_host_authenticated != NULL)? pauthed : 0)]
3249 protocols[pnormal + pcrpted])
3251 ((sender_host_address != NULL)? pnlocal : 0);
3253 sender_host_authenticated = NULL;
3254 authenticated_id = NULL;
3255 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3256 DEBUG(D_tls) debug_printf("TLS active\n");
3257 break; /* Successful STARTTLS */
3260 /* Some local configuration problem was discovered before actually trying
3261 to do a TLS handshake; give a temporary error. */
3263 else if (rc == DEFER)
3265 smtp_printf("454 TLS currently unavailable\r\n");
3269 /* Hard failure. Reject everything except QUIT or closed connection. One
3270 cause for failure is a nested STARTTLS, in which case tls_active remains
3271 set, but we must still reject all incoming commands. */
3273 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3276 switch(smtp_read_command(FALSE))
3279 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3280 smtp_get_connection_info());
3285 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3286 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3287 smtp_get_connection_info());
3292 smtp_printf("554 Security failure\r\n");
3301 /* The ACL for QUIT is provided for gathering statistical information or
3302 similar; it does not affect the response code, but it can supply a custom
3306 incomplete_transaction_log(US"QUIT");
3308 if (acl_smtp_quit != NULL)
3310 rc = acl_check(ACL_WHERE_QUIT, US"", acl_smtp_quit,&user_msg,&log_msg);
3312 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3315 else user_msg = NULL;
3317 if (user_msg == NULL)
3318 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3320 smtp_printf("221 %s\r\n", user_msg);
3327 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3328 smtp_get_connection_info());
3333 incomplete_transaction_log(US"RSET");
3334 smtp_reset(reset_point);
3336 smtp_printf("250 Reset OK\r\n");
3337 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3342 smtp_printf("250 OK\r\n");
3346 /* Show ETRN/EXPN/VRFY if there's
3347 an ACL for checking hosts; if actually used, a check will be done for
3351 smtp_printf("214-Commands supported:\r\n");
3355 Ustrcat(buffer, " AUTH");
3357 Ustrcat(buffer, " STARTTLS");
3359 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3360 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3361 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3362 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3363 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3364 smtp_printf("214%s\r\n", buffer);
3370 incomplete_transaction_log(US"connection lost");
3371 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3373 /* Don't log by default unless in the middle of a message, as some mailers
3374 just drop the call rather than sending QUIT, and it clutters up the logs.
3377 if (sender_address != NULL || recipients_count > 0)
3378 log_write(L_lost_incoming_connection,
3380 "unexpected %s while reading SMTP command from %s%s",
3381 sender_host_unknown? "EOF" : "disconnection",
3382 host_and_ident(FALSE), smtp_read_error);
3384 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3385 smtp_get_connection_info(), smtp_read_error);
3392 if (sender_address != NULL)
3394 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3395 US"ETRN is not permitted inside a transaction");
3399 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_data,
3400 host_and_ident(FALSE));
3402 rc = acl_check(ACL_WHERE_ETRN, smtp_data, acl_smtp_etrn, &user_msg,
3406 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3410 /* Compute the serialization key for this command. */
3412 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_data);
3414 /* If a command has been specified for running as a result of ETRN, we
3415 permit any argument to ETRN. If not, only the # standard form is permitted,
3416 since that is strictly the only kind of ETRN that can be implemented
3417 according to the RFC. */
3419 if (smtp_etrn_command != NULL)
3423 etrn_command = smtp_etrn_command;
3424 deliver_domain = smtp_data;
3425 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3426 US"ETRN processing", &error);
3427 deliver_domain = NULL;
3430 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3432 smtp_printf("458 Internal failure\r\n");
3437 /* Else set up to call Exim with the -R option. */
3441 if (*smtp_data++ != '#')
3443 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3444 US"argument must begin with #");
3447 etrn_command = US"exim -R";
3448 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3452 /* If we are host-testing, don't actually do anything. */
3458 debug_printf("ETRN command is: %s\n", etrn_command);
3459 debug_printf("ETRN command execution skipped\n");
3461 smtp_printf("250 OK\r\n");
3466 /* If ETRN queue runs are to be serialized, check the database to
3467 ensure one isn't already running. */
3469 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3471 smtp_printf("458 Already processing %s\r\n", smtp_data);
3475 /* Fork a child process and run the command. We don't want to have to
3476 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3477 forking. It should be set that way anyway for external incoming SMTP,
3478 but we save and restore to be tidy. If serialization is required, we
3479 actually run the command in yet another process, so we can wait for it
3480 to complete and then remove the serialization lock. */
3482 oldsignal = signal(SIGCHLD, SIG_IGN);
3484 if ((pid = fork()) == 0)
3486 smtp_input = FALSE; /* This process is not associated with the */
3487 fclose(smtp_in); /* SMTP call any more. */
3490 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3492 /* If not serializing, do the exec right away. Otherwise, fork down
3493 into another process. */
3495 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3497 DEBUG(D_exec) debug_print_argv(argv);
3498 exim_nullstd(); /* Ensure std{in,out,err} exist */
3499 execv(CS argv[0], (char *const *)argv);
3500 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3501 etrn_command, strerror(errno));
3502 _exit(EXIT_FAILURE); /* paranoia */
3505 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3506 is, we are in the first subprocess, after forking again. All we can do
3507 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3508 complete, before removing the serialization. */
3511 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3512 "failed: %s", strerror(errno));
3516 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3518 (void)wait(&status);
3519 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3523 enq_end(etrn_serialize_key);
3524 _exit(EXIT_SUCCESS);
3527 /* Back in the top level SMTP process. Check that we started a subprocess
3528 and restore the signal state. */
3532 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3534 smtp_printf("458 Unable to fork process\r\n");
3535 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3537 else smtp_printf("250 OK\r\n");
3539 signal(SIGCHLD, oldsignal);
3544 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3545 US"unexpected argument data");
3549 /* This currently happens only for NULLs, but could be extended. */
3552 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3553 US"NULL character(s) present (shown as '?')");
3554 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3559 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3560 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3561 c = smtp_inend - smtp_inptr;
3562 if (c > 150) c = 150;
3564 incomplete_transaction_log(US"sync failure");
3565 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: "
3566 "synchronization error "
3567 "(next input sent too soon: pipelining was%s advertised): "
3568 "rejected \"%s\" %s next input=\"%s\"",
3569 pipelining_advertised? "" : " not",
3570 cmd_buffer, host_and_ident(TRUE),
3571 string_printing(smtp_inptr));
3572 smtp_printf("554 SMTP synchronization error\r\n");
3573 done = 1; /* Pretend eof - drops connection */
3577 case TOO_MANY_NONMAIL_CMD:
3578 incomplete_transaction_log(US"too many non-mail commands");
3579 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3580 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
3581 smtp_data - cmd_buffer, cmd_buffer);
3582 smtp_printf("554 Too many nonmail commands\r\n");
3583 done = 1; /* Pretend eof - drops connection */
3588 if (unknown_command_count++ >= smtp_max_unknown_commands)
3590 log_write(L_smtp_syntax_error, LOG_MAIN,
3591 "SMTP syntax error in \"%s\" %s %s",
3592 string_printing(cmd_buffer), host_and_ident(TRUE),
3593 US"unrecognized command");
3594 incomplete_transaction_log(US"unrecognized command");
3595 smtp_printf("500 Too many unrecognized commands\r\n");
3597 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3598 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3602 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3603 US"unrecognized command");
3607 /* This label is used by goto's inside loops that want to break out to
3608 the end of the command-processing loop. */
3611 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3612 last_was_rcpt = was_rcpt; /* protocol error handling */
3616 return done - 2; /* Convert yield values */
3619 /* End of smtp_in.c */