1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.15 2005/03/29 15:53:12 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2005 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. */
42 #define cmd_buffer_size 2048
44 /* Size of buffer for reading SMTP incoming packets */
46 #define in_buffer_size 8192
48 /* Structure for SMTP command list */
55 short int is_mail_cmd;
58 /* Codes for identifying commands. We order them so that those that come first
59 are those for which synchronization is always required. Checking this can help
63 /* These commands are required to be synchronized, i.e. to be the last in a
64 block of commands when pipelining. */
66 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
67 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
68 ETRN_CMD, /* This by analogy with TURN from the RFC */
69 STARTTLS_CMD, /* Required by the STARTTLS RFC */
71 /* This is a dummy to identify the non-sync commands when pipelining */
73 NON_SYNC_CMD_PIPELINING,
75 /* These commands need not be synchronized when pipelining */
77 MAIL_CMD, RCPT_CMD, RSET_CMD,
79 /* This is a dummy to identify the non-sync commands when not pipelining */
81 NON_SYNC_CMD_NON_PIPELINING,
83 /* I have been unable to find a statement about the use of pipelining
84 with AUTH, so to be on the safe side it is here, though I kind of feel
85 it should be up there with the synchronized commands. */
89 /* I'm not sure about these, but I don't think they matter. */
93 /* These are specials that don't correspond to actual commands */
95 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
96 TOO_MANY_NONMAIL_CMD };
100 /*************************************************
101 * Local static variables *
102 *************************************************/
104 static auth_instance *authenticated_by;
105 static BOOL auth_advertised;
107 static BOOL tls_advertised;
110 static BOOL helo_required = FALSE;
111 static BOOL helo_verify = FALSE;
112 static BOOL helo_seen;
113 static BOOL helo_accept_junk;
114 static BOOL count_nonmail;
115 static BOOL pipelining_advertised;
116 static int nonmail_command_count;
117 static int synprot_error_count;
118 static int unknown_command_count;
119 static int sync_cmd_limit;
120 static int smtp_write_error = 0;
122 static uschar *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;
808 acl_warn_headers = NULL;
809 queue_only_policy = FALSE;
810 deliver_freeze = FALSE; /* Can be set by ACL */
811 fake_reject = FALSE; /* Can be set by ACL */
812 #ifdef WITH_CONTENT_SCAN
813 no_mbox_unspool = FALSE; /* Can be set by ACL */
815 submission_mode = FALSE; /* Can be set by ACL */
816 active_local_from_check = local_from_check; /* Can be set by ACL */
817 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
818 sender_address = NULL;
819 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
820 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
821 sender_verified_list = NULL; /* No senders verified */
822 memset(sender_address_cache, 0, sizeof(sender_address_cache));
823 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
824 authenticated_sender = NULL;
825 #ifdef EXPERIMENTAL_BRIGHTMAIL
829 #ifdef EXPERIMENTAL_DOMAINKEYS
832 #ifdef EXPERIMENTAL_SPF
833 spf_header_comment = NULL;
836 spf_smtp_comment = NULL;
838 body_linecount = body_zerocount = 0;
840 for (i = 0; i < ACL_M_MAX; i++) acl_var[ACL_C_MAX + i] = NULL;
842 /* The message body variables use malloc store. They may be set if this is
843 not the first message in an SMTP session and the previous message caused them
844 to be referenced in an ACL. */
846 if (message_body != NULL)
848 store_free(message_body);
852 if (message_body_end != NULL)
854 store_free(message_body_end);
855 message_body_end = NULL;
858 /* Warning log messages are also saved in malloc store. They are saved to avoid
859 repetition in the same message, but it seems right to repeat them for different
862 while (acl_warn_logged != NULL)
864 string_item *this = acl_warn_logged;
865 acl_warn_logged = acl_warn_logged->next;
874 /*************************************************
875 * Initialize for incoming batched SMTP message *
876 *************************************************/
878 /* This function is called from smtp_setup_msg() in the case when
879 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
880 of messages in one file with SMTP commands between them. All errors must be
881 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
882 relevant. After an error on a sender, or an invalid recipient, the remainder
883 of the message is skipped. The value of received_protocol is already set.
886 Returns: > 0 message successfully started (reached DATA)
887 = 0 QUIT read or end of file reached
892 smtp_setup_batch_msg(void)
895 void *reset_point = store_get(0);
897 /* Save the line count at the start of each transaction - single commands
898 like HELO and RSET count as whole transactions. */
900 bsmtp_transaction_linecount = receive_linecount;
902 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
904 smtp_reset(reset_point); /* Reset for start of message */
906 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
907 value. The values are 2 larger than the required yield of the function. */
912 uschar *recipient = NULL;
913 int start, end, sender_domain, recipient_domain;
915 switch(smtp_read_command(FALSE))
917 /* The HELO/EHLO commands set sender_address_helo if they have
918 valid data; otherwise they are ignored, except that they do
919 a reset of the state. */
924 check_helo(smtp_data);
928 smtp_reset(reset_point);
929 bsmtp_transaction_linecount = receive_linecount;
933 /* The MAIL FROM command requires an address as an operand. All we
934 do here is to parse it for syntactic correctness. The form "<>" is
935 a special case which converts into an empty string. The start/end
936 pointers in the original are not used further for this address, as
937 it is the canonical extracted address which is all that is kept. */
940 if (sender_address != NULL)
941 /* The function moan_smtp_batch() does not return. */
942 moan_smtp_batch(cmd_buffer, "503 Sender already given");
944 if (smtp_data[0] == 0)
945 /* The function moan_smtp_batch() does not return. */
946 moan_smtp_batch(cmd_buffer, "501 MAIL FROM must have an address operand");
948 /* Reset to start of message */
950 smtp_reset(reset_point);
952 /* Apply SMTP rewrite */
954 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
955 rewrite_one(smtp_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
956 US"", global_rewrite_rules) : smtp_data;
958 /* Extract the address; the TRUE flag allows <> as valid */
961 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
964 if (raw_sender == NULL)
965 /* The function moan_smtp_batch() does not return. */
966 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
968 sender_address = string_copy(raw_sender);
970 /* Qualify unqualified sender addresses if permitted to do so. */
972 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
974 if (allow_unqualified_sender)
976 sender_address = rewrite_address_qualify(sender_address, FALSE);
977 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
978 "and rewritten\n", raw_sender);
980 /* The function moan_smtp_batch() does not return. */
981 else moan_smtp_batch(cmd_buffer, "501 sender address must contain "
987 /* The RCPT TO command requires an address as an operand. All we do
988 here is to parse it for syntactic correctness. There may be any number
989 of RCPT TO commands, specifying multiple senders. We build them all into
990 a data structure that is in argc/argv format. The start/end values
991 given by parse_extract_address are not used, as we keep only the
992 extracted address. */
995 if (sender_address == NULL)
996 /* The function moan_smtp_batch() does not return. */
997 moan_smtp_batch(cmd_buffer, "503 No sender yet given");
999 if (smtp_data[0] == 0)
1000 /* The function moan_smtp_batch() does not return. */
1001 moan_smtp_batch(cmd_buffer, "501 RCPT TO must have an address operand");
1003 /* Check maximum number allowed */
1005 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1006 /* The function moan_smtp_batch() does not return. */
1007 moan_smtp_batch(cmd_buffer, "%s too many recipients",
1008 recipients_max_reject? "552": "452");
1010 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1011 recipient address */
1013 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1014 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
1015 global_rewrite_rules) : smtp_data;
1017 /* rfc821_domains = TRUE; << no longer needed */
1018 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1019 &recipient_domain, FALSE);
1020 /* rfc821_domains = FALSE; << no longer needed */
1022 if (recipient == NULL)
1023 /* The function moan_smtp_batch() does not return. */
1024 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
1026 /* If the recipient address is unqualified, qualify it if permitted. Then
1027 add it to the list of recipients. */
1029 if (recipient_domain == 0)
1031 if (allow_unqualified_recipient)
1033 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1035 recipient = rewrite_address_qualify(recipient, TRUE);
1037 /* The function moan_smtp_batch() does not return. */
1038 else moan_smtp_batch(cmd_buffer, "501 recipient address must contain "
1041 receive_add_recipient(recipient, -1);
1045 /* The DATA command is legal only if it follows successful MAIL FROM
1046 and RCPT TO commands. This function is complete when a valid DATA
1047 command is encountered. */
1050 if (sender_address == NULL || recipients_count <= 0)
1052 /* The function moan_smtp_batch() does not return. */
1053 if (sender_address == NULL)
1054 moan_smtp_batch(cmd_buffer,
1055 "503 MAIL FROM:<sender> command must precede DATA");
1057 moan_smtp_batch(cmd_buffer,
1058 "503 RCPT TO:<recipient> must precede DATA");
1062 done = 3; /* DATA successfully achieved */
1063 message_ended = END_NOTENDED; /* Indicate in middle of message */
1068 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1075 bsmtp_transaction_linecount = receive_linecount;
1086 /* The function moan_smtp_batch() does not return. */
1087 moan_smtp_batch(cmd_buffer, "501 Unexpected argument data");
1092 /* The function moan_smtp_batch() does not return. */
1093 moan_smtp_batch(cmd_buffer, "501 Unexpected NULL in SMTP command");
1098 /* The function moan_smtp_batch() does not return. */
1099 moan_smtp_batch(cmd_buffer, "500 Command unrecognized");
1104 return done - 2; /* Convert yield values */
1110 /*************************************************
1111 * Start an SMTP session *
1112 *************************************************/
1114 /* This function is called at the start of an SMTP session. Thereafter,
1115 smtp_setup_msg() is called to initiate each separate message. This
1116 function does host-specific testing, and outputs the banner line.
1119 Returns: FALSE if the session can not continue; something has
1120 gone wrong, or the connection to the host is blocked
1124 smtp_start_session(void)
1130 /* If we are running in the test harness, and the incoming call is from
1131 127.0.0.2 (sic), have a short delay. This makes it possible to test handling of
1132 input sent too soon (before the banner is output). */
1134 if (running_in_test_harness &&
1135 sender_host_address != NULL &&
1136 Ustrcmp(sender_host_address, "127.0.0.2") == 0)
1139 /* Default values for certain variables */
1141 helo_seen = esmtp = helo_accept_junk = FALSE;
1142 count_nonmail = TRUE_UNSET;
1143 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1144 smtp_delay_mail = smtp_rlm_base;
1145 auth_advertised = FALSE;
1146 pipelining_advertised = FALSE;
1147 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1149 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1151 sender_host_authenticated = NULL;
1152 authenticated_by = NULL;
1155 tls_cipher = tls_peerdn = NULL;
1156 tls_advertised = FALSE;
1159 /* Reset ACL connection variables */
1161 for (i = 0; i < ACL_C_MAX; i++) acl_var[i] = NULL;
1163 cmd_buffer = (uschar *)malloc(cmd_buffer_size + 1); /* allow for trailing 0 */
1164 if (cmd_buffer == NULL)
1165 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1166 "malloc() failed for SMTP command buffer");
1168 /* For batched input, the protocol setting can be overridden from the
1169 command line by a trusted caller. */
1171 if (smtp_batched_input)
1173 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1176 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1177 reset later if any of EHLO/AUTH/STARTTLS are received. */
1181 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1183 /* Set up the buffer for inputting using direct read() calls, and arrange to
1184 call the local functions instead of the standard C ones. */
1186 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1187 if (smtp_inbuffer == NULL)
1188 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1189 receive_getc = smtp_getc;
1190 receive_ungetc = smtp_ungetc;
1191 receive_feof = smtp_feof;
1192 receive_ferror = smtp_ferror;
1193 smtp_inptr = smtp_inend = smtp_inbuffer;
1194 smtp_had_eof = smtp_had_error = 0;
1196 /* Set up the message size limit; this may be host-specific */
1198 thismessage_size_limit = expand_string_integer(message_size_limit);
1199 if (thismessage_size_limit < 0)
1201 if (thismessage_size_limit == -1)
1202 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1203 "%s", expand_string_message);
1205 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1206 "%s", expand_string_message);
1207 smtp_closedown(US"Temporary local problem - please try later");
1211 /* When a message is input locally via the -bs or -bS options, sender_host_
1212 unknown is set unless -oMa was used to force an IP address, in which case it
1213 is checked like a real remote connection. When -bs is used from inetd, this
1214 flag is not set, causing the sending host to be checked. The code that deals
1215 with IP source routing (if configured) is never required for -bs or -bS and
1216 the flag sender_host_notsocket is used to suppress it.
1218 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1219 reserve for certain hosts and/or networks. */
1221 if (!sender_host_unknown)
1224 BOOL reserved_host = FALSE;
1226 /* Look up IP options (source routing info) on the socket if this is not an
1227 -oMa "host", and if any are found, log them and drop the connection.
1229 Linux (and others now, see below) is different to everyone else, so there
1230 has to be some conditional compilation here. Versions of Linux before 2.1.15
1231 used a structure whose name was "options". Somebody finally realized that
1232 this name was silly, and it got changed to "ip_options". I use the
1233 newer name here, but there is a fudge in the script that sets up os.h
1234 to define a macro in older Linux systems.
1236 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1237 glibc 2, which has chosen ip_opts for the structure name. This is now
1238 really a glibc thing rather than a Linux thing, so the condition name
1239 has been changed to reflect this. It is relevant also to GNU/Hurd.
1241 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1242 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1243 a special macro defined in the os.h file.
1245 Some DGUX versions on older hardware appear not to support IP options at
1246 all, so there is now a general macro which can be set to cut out this
1249 How to do this properly in IPv6 is not yet known. */
1251 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1253 #ifdef GLIBC_IP_OPTIONS
1254 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1259 #elif defined DARWIN_IP_OPTIONS
1265 if (!host_checking && !sender_host_notsocket)
1268 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1269 struct ip_options *ipopt = store_get(optlen);
1271 struct ip_opts ipoptblock;
1272 struct ip_opts *ipopt = &ipoptblock;
1273 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1275 struct ipoption ipoptblock;
1276 struct ipoption *ipopt = &ipoptblock;
1277 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1280 /* Occasional genuine failures of getsockopt() have been seen - for
1281 example, "reset by peer". Therefore, just log and give up on this
1282 call, unless the error is ENOPROTOOPT. This error is given by systems
1283 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1284 of writing. So for that error, carry on - we just can't do an IP options
1287 DEBUG(D_receive) debug_printf("checking for IP options\n");
1289 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1292 if (errno != ENOPROTOOPT)
1294 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1295 host_and_ident(FALSE), strerror(errno));
1296 smtp_printf("451 SMTP service not available\r\n");
1301 /* Deal with any IP options that are set. On the systems I have looked at,
1302 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1303 more logging data than will fit in big_buffer. Nevertheless, after somebody
1304 questioned this code, I've added in some paranoid checking. */
1306 else if (optlen > 0)
1308 uschar *p = big_buffer;
1309 uschar *pend = big_buffer + big_buffer_size;
1310 uschar *opt, *adptr;
1312 struct in_addr addr;
1315 uschar *optstart = (uschar *)(ipopt->__data);
1317 uschar *optstart = (uschar *)(ipopt->ip_opts);
1319 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1322 DEBUG(D_receive) debug_printf("IP options exist\n");
1324 Ustrcpy(p, "IP options on incoming call:");
1327 for (opt = optstart; opt != NULL &&
1328 opt < (uschar *)(ipopt) + optlen;)
1342 if (!string_format(p, pend-p, " %s [@%s",
1343 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1345 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1347 inet_ntoa(ipopt->ip_dst)))
1349 inet_ntoa(ipopt->ipopt_dst)))
1357 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1359 while (optcount-- > 0)
1361 memcpy(&addr, adptr, sizeof(addr));
1362 if (!string_format(p, pend - p - 1, "%s%s",
1363 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1369 adptr += sizeof(struct in_addr);
1378 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1381 for (i = 0; i < opt[1]; i++)
1383 sprintf(CS p, "%2.2x ", opt[i]);
1394 log_write(0, LOG_MAIN, "%s", big_buffer);
1396 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1398 log_write(0, LOG_MAIN|LOG_REJECT,
1399 "connection from %s refused (IP options)", host_and_ident(FALSE));
1401 smtp_printf("554 SMTP service not available\r\n");
1405 /* Length of options = 0 => there are no options */
1407 else DEBUG(D_receive) debug_printf("no IP options found\n");
1409 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1411 /* Set keep-alive in socket options. The option is on by default. This
1412 setting is an attempt to get rid of some hanging connections that stick in
1413 read() when the remote end (usually a dialup) goes away. */
1415 if (smtp_accept_keepalive && !sender_host_notsocket)
1416 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1418 /* If the current host matches host_lookup, set the name by doing a
1419 reverse lookup. On failure, sender_host_name will be NULL and
1420 host_lookup_failed will be TRUE. This may or may not be serious - optional
1423 if (verify_check_host(&host_lookup) == OK)
1425 (void)host_name_lookup();
1426 host_build_sender_fullhost();
1429 /* Delay this until we have the full name, if it is looked up. */
1431 set_process_info("handling incoming connection from %s",
1432 host_and_ident(FALSE));
1434 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1435 smtps port for use with older style SSL MTAs. */
1438 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1442 /* Test for explicit connection rejection */
1444 if (verify_check_host(&host_reject_connection) == OK)
1446 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1447 "from %s (host_reject_connection)", host_and_ident(FALSE));
1448 smtp_printf("554 SMTP service not available\r\n");
1452 /* Test with TCP Wrappers if so configured */
1454 #ifdef USE_TCP_WRAPPERS
1455 if (!hosts_ctl("exim",
1456 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1457 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1458 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1460 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1461 log_write(L_connection_reject,
1462 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1463 "(tcp wrappers)", host_and_ident(FALSE));
1464 smtp_printf("554 SMTP service not available\r\n");
1469 /* Check for reserved slots. Note that the count value doesn't include
1470 this process, as it gets upped in the parent process. */
1472 if (smtp_accept_max > 0 &&
1473 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1475 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1477 log_write(L_connection_reject,
1478 LOG_MAIN, "temporarily refused connection from %s: not in "
1479 "reserve list: connected=%d max=%d reserve=%d%s",
1480 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1481 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1482 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1483 "please try again later\r\n", smtp_active_hostname);
1486 reserved_host = TRUE;
1489 /* If a load level above which only messages from reserved hosts are
1490 accepted is set, check the load. For incoming calls via the daemon, the
1491 check is done in the superior process if there are no reserved hosts, to
1492 save a fork. In all cases, the load average will already be available
1493 in a global variable at this point. */
1495 if (smtp_load_reserve >= 0 &&
1496 load_average > smtp_load_reserve &&
1498 verify_check_host(&smtp_reserve_hosts) != OK)
1500 log_write(L_connection_reject,
1501 LOG_MAIN, "temporarily refused connection from %s: not in "
1502 "reserve list and load average = %.2f", host_and_ident(FALSE),
1503 (double)load_average/1000.0);
1504 smtp_printf("421 %s: Too much load; please try again later\r\n",
1505 smtp_active_hostname);
1509 /* Determine whether unqualified senders or recipients are permitted
1510 for this host. Unfortunately, we have to do this every time, in order to
1511 set the flags so that they can be inspected when considering qualifying
1512 addresses in the headers. For a site that permits no qualification, this
1513 won't take long, however. */
1515 allow_unqualified_sender =
1516 verify_check_host(&sender_unqualified_hosts) == OK;
1518 allow_unqualified_recipient =
1519 verify_check_host(&recipient_unqualified_hosts) == OK;
1521 /* Determine whether HELO/EHLO is required for this host. The requirement
1522 can be hard or soft. */
1524 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1526 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1528 /* Determine whether this hosts is permitted to send syntactic junk
1529 after a HELO or EHLO command. */
1531 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1534 /* For batch SMTP input we are now done. */
1536 if (smtp_batched_input) return TRUE;
1538 /* Run the ACL if it exists */
1540 if (acl_smtp_connect != NULL)
1543 uschar *user_msg, *log_msg;
1544 smtp_data = US"in \"connect\" ACL"; /* For logged failure message */
1545 rc = acl_check(ACL_WHERE_CONNECT, US"", acl_smtp_connect, &user_msg,
1549 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1554 /* Output the initial message for a two-way SMTP connection. It may contain
1555 newlines, which then cause a multi-line response to be given. */
1557 s = expand_string(smtp_banner);
1559 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1560 "failed: %s", smtp_banner, expand_string_message);
1562 /* Remove any terminating newlines; might as well remove trailing space too */
1565 while (p > s && isspace(p[-1])) p--;
1568 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1569 is all contained in a single IP packet. The original code wrote out the
1570 greeting using several calls to fprint/fputc, and on busy servers this could
1571 cause it to be split over more than one packet - which caused CC:Mail to fall
1572 over when it got the second part of the greeting after sending its first
1573 command. Sigh. To try to avoid this, build the complete greeting message
1574 first, and output it in one fell swoop. This gives a better chance of it
1575 ending up as a single packet. */
1577 ss = store_get(size);
1581 do /* At least once, in case we have an empty string */
1584 uschar *linebreak = Ustrchr(p, '\n');
1585 if (linebreak == NULL)
1588 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1592 len = linebreak - p;
1593 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1595 ss = string_cat(ss, &size, &ptr, p, len);
1596 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1598 if (linebreak != NULL) p++;
1602 ss[ptr] = 0; /* string_cat leaves room for this */
1604 /* Before we write the banner, check that there is no input pending, unless
1605 this synchronisation check is disabled. */
1607 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1610 struct timeval tzero;
1614 FD_SET(fileno(smtp_in), &fds);
1615 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1618 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1621 if (rc > 150) rc = 150;
1622 smtp_inbuffer[rc] = 0;
1623 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: "
1624 "synchronization error (input sent without waiting for greeting): "
1625 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1626 string_printing(smtp_inbuffer));
1627 smtp_printf("554 SMTP synchronization error\r\n");
1633 /* Now output the banner */
1635 smtp_printf("%s", ss);
1643 /*************************************************
1644 * Handle SMTP syntax and protocol errors *
1645 *************************************************/
1647 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1648 to do so. Then transmit the error response. The return value depends on the
1649 number of syntax and protocol errors in this SMTP session.
1652 type error type, given as a log flag bit
1653 code response code; <= 0 means don't send a response
1654 data data to reflect in the response (can be NULL)
1655 errmess the error message
1657 Returns: -1 limit of syntax/protocol errors NOT exceeded
1658 +1 limit of syntax/protocol errors IS exceeded
1660 These values fit in with the values of the "done" variable in the main
1661 processing loop in smtp_setup_msg(). */
1664 synprot_error(int type, int code, uschar *data, uschar *errmess)
1668 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1669 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1670 string_printing(cmd_buffer), host_and_ident(TRUE), errmess);
1672 if (++synprot_error_count > smtp_max_synprot_errors)
1675 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1676 "syntax or protocol errors (last command was \"%s\")",
1677 host_and_ident(FALSE), cmd_buffer);
1682 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1683 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1685 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1694 /*************************************************
1695 * Log incomplete transactions *
1696 *************************************************/
1698 /* This function is called after a transaction has been aborted by RSET, QUIT,
1699 connection drops or other errors. It logs the envelope information received
1700 so far in order to preserve address verification attempts.
1702 Argument: string to indicate what aborted the transaction
1707 incomplete_transaction_log(uschar *what)
1709 if (sender_address == NULL || /* No transaction in progress */
1710 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1713 /* Build list of recipients for logging */
1715 if (recipients_count > 0)
1718 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1719 for (i = 0; i < recipients_count; i++)
1720 raw_recipients[i] = recipients_list[i].address;
1721 raw_recipients_count = recipients_count;
1724 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1725 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1731 /*************************************************
1732 * Send SMTP response, possibly multiline *
1733 *************************************************/
1735 /* There are, it seems, broken clients out there that cannot handle multiline
1736 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1737 output nothing for non-final calls, and only the first line for anything else.
1741 final FALSE if the last line isn't the final line
1742 msg message text, possibly containing newlines
1748 smtp_respond(int code, BOOL final, uschar *msg)
1750 if (!final && no_multiline_responses) return;
1754 uschar *nl = Ustrchr(msg, '\n');
1757 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1760 else if (nl[1] == 0 || no_multiline_responses)
1762 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1767 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1769 while (isspace(*msg)) msg++;
1777 /*************************************************
1778 * Handle an ACL failure *
1779 *************************************************/
1781 /* This function is called when acl_check() fails. As well as calls from within
1782 this module, it is called from receive.c for an ACL after DATA. It sorts out
1783 logging the incident, and sets up the error response. A message containing
1784 newlines is turned into a multiline SMTP response, but for logging, only the
1787 There's a table of the response codes to use in globals.c, along with the table
1788 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1789 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1790 that the response should be 252 in the disabled state, because there are broken
1791 clients that try VRFY before RCPT. A 5xx response should be given only when the
1792 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1793 given on refusal, and for AUTH, 503.
1796 where where the ACL was called from
1798 user_msg a message that can be included in an SMTP response
1799 log_msg a message for logging
1801 Returns: 0 in most cases
1802 2 if the failure code was FAIL_DROP, in which case the
1803 SMTP connection should be dropped (this value fits with the
1804 "done" variable in smtp_setup_msg() below)
1808 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1810 int code = acl_wherecodes[where];
1811 BOOL drop = rc == FAIL_DROP;
1813 uschar *sender_info = US"";
1814 uschar *what = (where == ACL_WHERE_PREDATA)? US"DATA" :
1815 #ifdef WITH_CONTENT_SCAN
1816 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1818 (where == ACL_WHERE_DATA)? US"after DATA" :
1819 string_sprintf("%s %s", acl_wherenames[where], smtp_data);
1821 if (drop) rc = FAIL;
1823 /* We used to have sender_address here; however, there was a bug that was not
1824 updating sender_address after a rewrite during a verify. When this bug was
1825 fixed, sender_address at this point became the rewritten address. I'm not sure
1826 this is what should be logged, so I've changed to logging the unrewritten
1827 address to retain backward compatibility. */
1829 #ifndef WITH_CONTENT_SCAN
1830 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1832 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1835 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1836 sender_address_unrewritten : sender_address);
1839 /* If there's been a sender verification failure with a specific message, and
1840 we have not sent a response about it yet, do so now, as a preliminary line for
1841 failures, but not defers. However, log it in both cases. */
1843 if (sender_verified_failed != NULL &&
1844 !testflag(sender_verified_failed, af_sverify_told))
1846 setflag(sender_verified_failed, af_sverify_told);
1848 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1849 host_and_ident(TRUE),
1850 ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail",
1851 sender_verified_failed->address,
1852 (sender_verified_failed->message == NULL)? US"" :
1853 string_sprintf(": %s", sender_verified_failed->message));
1855 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1856 smtp_respond(code, FALSE, string_sprintf(
1857 testflag(sender_verified_failed, af_verify_pmfail)?
1858 "Postmaster verification failed while checking <%s>\n%s\n"
1859 "Several RFCs state that you are required to have a postmaster\n"
1860 "mailbox for each mail domain. This host does not accept mail\n"
1861 "from domains whose servers reject the postmaster address."
1863 testflag(sender_verified_failed, af_verify_nsfail)?
1864 "Callback setup failed while verifying <%s>\n%s\n"
1865 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1866 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1867 "RFC requirements, and stops you from receiving standard bounce\n"
1868 "messages. This host does not accept mail from domains whose servers\n"
1871 "Verification failed for <%s>\n%s",
1872 sender_verified_failed->address,
1873 sender_verified_failed->user_message));
1876 /* Sort out text for logging */
1878 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1879 lognl = Ustrchr(log_msg, '\n');
1880 if (lognl != NULL) *lognl = 0;
1882 /* Send permanent failure response to the command, but the code used isn't
1883 always a 5xx one - see comments at the start of this function. If the original
1884 rc was FAIL_DROP we drop the connection and yield 2. */
1886 if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1887 US"Administrative prohibition" : user_msg);
1889 /* Send temporary failure response to the command. Don't give any details,
1890 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1891 verb, and for a header verify when smtp_return_error_details is set.
1893 This conditional logic is all somewhat of a mess because of the odd
1894 interactions between temp_details and return_error_details. One day it should
1895 be re-implemented in a tidier fashion. */
1899 if (acl_temp_details && user_msg != NULL)
1901 if (smtp_return_error_details &&
1902 sender_verified_failed != NULL &&
1903 sender_verified_failed->message != NULL)
1905 smtp_respond(451, FALSE, sender_verified_failed->message);
1907 smtp_respond(451, TRUE, user_msg);
1910 smtp_printf("451 Temporary local problem - please try later\r\n");
1913 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
1914 Otherwise, log why it is closing if required and return 2. */
1916 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1917 host_and_ident(TRUE),
1918 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1920 if (!drop) return 0;
1922 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1923 smtp_get_connection_info());
1930 /*************************************************
1931 * Initialize for SMTP incoming message *
1932 *************************************************/
1934 /* This function conducts the initial dialogue at the start of an incoming SMTP
1935 message, and builds a list of recipients. However, if the incoming message
1936 is part of a batch (-bS option) a separate function is called since it would
1937 be messy having tests splattered about all over this function. This function
1938 therefore handles the case where interaction is occurring. The input and output
1939 files are set up in smtp_in and smtp_out.
1941 The global recipients_list is set to point to a vector of recipient_item
1942 blocks, whose number is given by recipients_count. This is extended by the
1943 receive_add_recipient() function. The global variable sender_address is set to
1944 the sender's address. The yield is +1 if a message has been successfully
1945 started, 0 if a QUIT command was encountered or the connection was refused from
1946 the particular host, or -1 if the connection was lost.
1950 Returns: > 0 message successfully started (reached DATA)
1951 = 0 QUIT read or end of file reached or call refused
1956 smtp_setup_msg(void)
1959 BOOL toomany = FALSE;
1960 BOOL discarded = FALSE;
1961 BOOL last_was_rej_mail = FALSE;
1962 BOOL last_was_rcpt = FALSE;
1963 void *reset_point = store_get(0);
1965 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
1967 /* Reset for start of new message. We allow one RSET not to be counted as a
1968 nonmail command, for those MTAs that insist on sending it between every
1969 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
1970 TLS between messages (an Exim client may do this if it has messages queued up
1971 for the host). Note: we do NOT reset AUTH at this point. */
1973 smtp_reset(reset_point);
1974 message_ended = END_NOTSTARTED;
1976 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
1977 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
1978 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
1980 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
1983 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
1985 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
1987 /* Batched SMTP is handled in a different function. */
1989 if (smtp_batched_input) return smtp_setup_batch_msg();
1991 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1992 value. The values are 2 larger than the required yield of the function. */
1997 uschar *etrn_command;
1998 uschar *etrn_serialize_key;
2000 uschar *user_msg, *log_msg;
2001 uschar *recipient = NULL;
2002 uschar *hello = NULL;
2003 uschar *set_id = NULL;
2005 BOOL was_rej_mail = FALSE;
2006 BOOL was_rcpt = FALSE;
2007 void (*oldsignal)(int);
2009 int start, end, sender_domain, recipient_domain;
2014 switch(smtp_read_command(TRUE))
2016 /* The AUTH command is not permitted to occur inside a transaction, and may
2017 occur successfully only once per connection, and then only when we've
2018 advertised it. Actually, that isn't quite true. When TLS is started, all
2019 previous information about a connection must be discarded, so a new AUTH is
2020 permitted at that time.
2022 AUTH is initially labelled as a "nonmail command" so that one occurrence
2023 doesn't get counted. We change the label here so that multiple failing
2024 AUTHS will eventually hit the nonmail threshold. */
2027 authentication_failed = TRUE;
2028 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2030 if (!auth_advertised)
2032 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2033 US"AUTH command used when not advertised");
2036 if (sender_host_authenticated != NULL)
2038 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2039 US"already authenticated");
2042 if (sender_address != NULL)
2044 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2045 US"not permitted in mail transaction");
2051 if (acl_smtp_auth != NULL)
2053 rc = acl_check(ACL_WHERE_AUTH, smtp_data, acl_smtp_auth, &user_msg,
2057 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2062 /* Find the name of the requested authentication mechanism. */
2065 while ((c = *smtp_data) != 0 && !isspace(c))
2067 if (!isalnum(c) && c != '-' && c != '_')
2069 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2070 US"invalid character in authentication mechanism name");
2076 /* If not at the end of the line, we must be at white space. Terminate the
2077 name and move the pointer on to any data that may be present. */
2079 if (*smtp_data != 0)
2082 while (isspace(*smtp_data)) smtp_data++;
2085 /* Search for an authentication mechanism which is configured for use
2086 as a server and which has been advertised. */
2088 for (au = auths; au != NULL; au = au->next)
2090 if (strcmpic(s, au->public_name) == 0 && au->server &&
2091 au->advertised) break;
2096 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2097 string_sprintf("%s authentication mechanism not supported", s));
2101 /* Run the checking code, passing the remainder of the command
2102 line as data. Initialize $0 empty. The authenticator may set up
2103 other numeric variables. Afterwards, have a go at expanding the set_id
2104 string, even if authentication failed - for bad passwords it can be useful
2105 to log the userid. On success, require set_id to expand and exist, and
2106 put it in authenticated_id. Save this in permanent store, as the working
2107 store gets reset at HELO, RSET, etc. */
2110 expand_nlength[0] = 0; /* $0 contains nothing */
2112 c = (au->info->servercode)(au, smtp_data);
2113 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2114 expand_nmax = -1; /* Reset numeric variables */
2116 /* For the non-OK cases, set up additional logging data if set_id
2121 if (set_id != NULL && *set_id != 0)
2122 set_id = string_sprintf(" (set_id=%s)", set_id);
2126 /* Switch on the result */
2131 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2133 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2134 sender_host_authenticated = au->name;
2135 authentication_failed = FALSE;
2137 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2138 ((sender_host_address != NULL)? pnlocal : 0);
2139 s = ss = US"235 Authentication succeeded";
2140 authenticated_by = au;
2144 /* Authentication succeeded, but we failed to expand the set_id string.
2145 Treat this as a temporary error. */
2147 auth_defer_msg = expand_string_message;
2151 s = string_sprintf("435 Unable to authenticate at present%s",
2152 auth_defer_user_msg);
2153 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2154 set_id, auth_defer_msg);
2158 s = ss = US"501 Invalid base64 data";
2162 s = ss = US"501 Authentication cancelled";
2166 s = ss = US"553 Initial data not expected";
2170 s = US"535 Incorrect authentication data";
2171 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2175 s = US"435 Internal error";
2176 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2177 "check", set_id, c);
2181 smtp_printf("%s\r\n", s);
2183 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2184 au->name, host_and_ident(FALSE), ss);
2186 break; /* AUTH_CMD */
2188 /* The HELO/EHLO commands are permitted to appear in the middle of a
2189 session as well as at the beginning. They have the effect of a reset in
2190 addition to their other functions. Their absence at the start cannot be
2191 taken to be an error.
2195 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2196 or 502 failure replies MUST be returned as appropriate. The SMTP
2197 server MUST stay in the same state after transmitting these replies
2198 that it was in before the EHLO was received.
2200 Therefore, we do not do the reset until after checking the command for
2201 acceptability. This change was made for Exim release 4.11. Previously
2202 it did the reset first. */
2213 HELO_EHLO: /* Common code for HELO and EHLO */
2214 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2215 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2217 /* Reject the HELO if its argument was invalid or non-existent. A
2218 successful check causes the argument to be saved in malloc store. */
2220 if (!check_helo(smtp_data))
2222 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2224 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2225 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2226 (*smtp_data == 0)? US"(no argument given)" :
2227 string_printing(smtp_data));
2229 if (++synprot_error_count > smtp_max_synprot_errors)
2231 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2232 "syntax or protocol errors (last command was \"%s\")",
2233 host_and_ident(FALSE), cmd_buffer);
2240 /* If sender_host_unknown is true, we have got here via the -bs interface,
2241 not called from inetd. Otherwise, we are running an IP connection and the
2242 host address will be set. If the helo name is the primary name of this
2243 host and we haven't done a reverse lookup, force one now. If helo_required
2244 is set, ensure that the HELO name matches the actual host. If helo_verify
2245 is set, do the same check, but softly. */
2247 if (!sender_host_unknown)
2249 BOOL old_helo_verified = helo_verified;
2250 uschar *p = smtp_data;
2252 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2255 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2256 because otherwise the log can be confusing. */
2258 if (sender_host_name == NULL &&
2259 (deliver_domain = sender_helo_name, /* set $domain */
2260 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2261 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2262 (void)host_name_lookup();
2264 /* Rebuild the fullhost info to include the HELO name (and the real name
2265 if it was looked up.) */
2267 host_build_sender_fullhost(); /* Rebuild */
2268 set_process_info("handling%s incoming connection from %s",
2269 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2271 /* Verify if configured. This doesn't give much security, but it does
2272 make some people happy to be able to do it. Note that HELO is legitimately
2273 allowed to quote an address literal. Allow for IPv6 ::ffff: literals. */
2275 helo_verified = FALSE;
2276 if (helo_required || helo_verify)
2278 BOOL tempfail = FALSE;
2280 HDEBUG(D_receive) debug_printf("verifying %s %s\n", hello,
2282 if (sender_helo_name[0] == '[')
2284 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2285 Ustrlen(sender_host_address)) == 0;
2290 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2291 helo_verified = Ustrncmp(sender_helo_name + 1,
2292 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2297 { if (helo_verified) debug_printf("matched host address\n"); }
2300 /* Do a reverse lookup if one hasn't already given a positive or
2301 negative response. If that fails, or the name doesn't match, try
2302 checking with a forward lookup. */
2306 if (sender_host_name == NULL && !host_lookup_failed)
2307 tempfail = host_name_lookup() == DEFER;
2309 /* If a host name is known, check it and all its aliases. */
2311 if (sender_host_name != NULL)
2313 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2317 HDEBUG(D_receive) debug_printf("matched host name\n");
2321 uschar **aliases = sender_host_aliases;
2322 while (*aliases != NULL)
2324 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2325 if (helo_verified) break;
2330 debug_printf("matched alias %s\n", *(--aliases));
2335 /* Final attempt: try a forward lookup of the helo name */
2341 h.name = sender_helo_name;
2345 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2347 rc = host_find_byname(&h, NULL, NULL, TRUE);
2348 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2353 if (Ustrcmp(hh->address, sender_host_address) == 0)
2355 helo_verified = TRUE;
2357 debug_printf("IP address for %s matches calling address\n",
2367 /* Verification failed. A temporary lookup failure gives a temporary
2374 smtp_printf("%d %s argument does not match calling host\r\n",
2375 tempfail? 451 : 550, hello);
2376 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2377 tempfail? "temporarily " : "",
2378 hello, sender_helo_name, host_and_ident(FALSE));
2379 helo_verified = old_helo_verified;
2380 break; /* End of HELO/EHLO processing */
2382 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2383 "helo_try_verify_hosts\n", hello);
2388 #ifdef EXPERIMENTAL_SPF
2389 /* set up SPF context */
2390 spf_init(sender_helo_name, sender_host_address);
2393 /* Apply an ACL check if one is defined */
2395 if (acl_smtp_helo != NULL)
2397 rc = acl_check(ACL_WHERE_HELO, smtp_data, acl_smtp_helo, &user_msg,
2401 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2402 sender_helo_name = NULL;
2403 host_build_sender_fullhost(); /* Rebuild */
2408 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2409 abandoning any previous message. */
2411 received_protocol = (esmtp?
2413 ((sender_host_authenticated != NULL)? pauthed : 0) +
2414 ((tls_active >= 0)? pcrpted : 0)]
2416 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2418 ((sender_host_address != NULL)? pnlocal : 0);
2420 smtp_reset(reset_point);
2423 /* Generate an OK reply, including the ident if present, and also
2424 the IP address if present. Reflecting back the ident is intended
2425 as a deterrent to mail forgers. For maximum efficiency, and also
2426 because some broken systems expect each response to be in a single
2427 packet, arrange that it is sent in one write(). */
2429 auth_advertised = FALSE;
2430 pipelining_advertised = FALSE;
2432 tls_advertised = FALSE;
2435 s = string_sprintf("250 %s Hello %s%s%s",
2436 smtp_active_hostname,
2437 (sender_ident == NULL)? US"" : sender_ident,
2438 (sender_ident == NULL)? US"" : US" at ",
2439 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2444 if (sender_host_address != NULL)
2446 s = string_cat(s, &size, &ptr, US" [", 2);
2447 s = string_cat(s, &size, &ptr, sender_host_address,
2448 Ustrlen(sender_host_address));
2449 s = string_cat(s, &size, &ptr, US"]", 1);
2452 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2454 /* If we received EHLO, we must create a multiline response which includes
2455 the functions supported. */
2461 /* I'm not entirely happy with this, as an MTA is supposed to check
2462 that it has enough room to accept a message of maximum size before
2463 it sends this. However, there seems little point in not sending it.
2464 The actual size check happens later at MAIL FROM time. By postponing it
2465 till then, VRFY and EXPN can be used after EHLO when space is short. */
2467 if (thismessage_size_limit > 0)
2469 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2470 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2474 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2477 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2478 clean; if it has an 8-bit character in its hand, it just sends it. It
2479 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2480 However, some users want this option simply in order to stop MUAs
2481 mangling messages that contain top-bit-set characters. It is therefore
2482 provided as an option. */
2484 if (accept_8bitmime)
2485 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2487 /* Advertise ETRN if there's an ACL checking whether a host is
2488 permitted to issue it; a check is made when any host actually tries. */
2490 if (acl_smtp_etrn != NULL)
2492 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2495 /* Advertise EXPN if there's an ACL checking whether a host is
2496 permitted to issue it; a check is made when any host actually tries. */
2498 if (acl_smtp_expn != NULL)
2500 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2503 /* Exim is quite happy with pipelining, so let the other end know that
2504 it is safe to use it, unless advertising is disabled. */
2506 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2508 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2509 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2510 pipelining_advertised = TRUE;
2513 /* If any server authentication mechanisms are configured, advertise
2514 them if the current host is in auth_advertise_hosts. The problem with
2515 advertising always is that some clients then require users to
2516 authenticate (and aren't configurable otherwise) even though it may not
2517 be necessary (e.g. if the host is in host_accept_relay).
2519 RFC 2222 states that SASL mechanism names contain only upper case
2520 letters, so output the names in upper case, though we actually recognize
2521 them in either case in the AUTH command. */
2525 if (verify_check_host(&auth_advertise_hosts) == OK)
2529 for (au = auths; au != NULL; au = au->next)
2531 if (au->server && (au->advertise_condition == NULL ||
2532 expand_check_condition(au->advertise_condition, au->name,
2533 US"authenticator")))
2538 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2540 auth_advertised = TRUE;
2543 s = string_cat(s, &size, &ptr, US" ", 1);
2544 s = string_cat(s, &size, &ptr, au->public_name,
2545 Ustrlen(au->public_name));
2546 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2547 au->advertised = TRUE;
2549 else au->advertised = FALSE;
2551 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2555 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2556 if it has been included in the binary, and the host matches
2557 tls_advertise_hosts. We must *not* advertise if we are already in a
2558 secure connection. */
2561 if (tls_active < 0 &&
2562 verify_check_host(&tls_advertise_hosts) != FAIL)
2564 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2565 tls_advertised = TRUE;
2569 /* Finish off the multiline reply with one that is always available. */
2571 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2574 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2580 if (tls_active >= 0) (void)tls_write(s, ptr); else
2583 fwrite(s, 1, ptr, smtp_out);
2584 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2586 break; /* HELO/EHLO */
2589 /* The MAIL command requires an address as an operand. All we do
2590 here is to parse it for syntactic correctness. The form "<>" is
2591 a special case which converts into an empty string. The start/end
2592 pointers in the original are not used further for this address, as
2593 it is the canonical extracted address which is all that is kept. */
2596 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2597 was_rej_mail = TRUE; /* Reset if accepted */
2599 if (helo_required && !helo_seen)
2601 smtp_printf("503 HELO or EHLO required\r\n");
2602 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2603 "HELO/EHLO given", host_and_ident(FALSE));
2607 if (sender_address != NULL)
2609 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2610 US"sender already given");
2614 if (smtp_data[0] == 0)
2616 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2617 US"MAIL must have an address operand");
2621 /* Check to see if the limit for messages per connection would be
2622 exceeded by accepting further messages. */
2624 if (smtp_accept_max_per_connection > 0 &&
2625 smtp_mailcmd_count > smtp_accept_max_per_connection)
2627 smtp_printf("421 too many messages in this connection\r\n");
2628 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2629 "messages in one connection", host_and_ident(TRUE));
2633 /* Reset for start of message - even if this is going to fail, we
2634 obviously need to throw away any previous data. */
2636 smtp_reset(reset_point);
2638 sender_data = recipient_data = NULL;
2640 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2644 uschar *name, *value, *end;
2645 unsigned long int size;
2647 if (!extract_option(&name, &value)) break;
2649 /* Handle SIZE= by reading the value. We don't do the check till later,
2650 in order to be able to log the sender address on failure. */
2652 if (strcmpic(name, US"SIZE") == 0 &&
2653 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2655 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2657 message_size = (int)size;
2660 /* If this session was initiated with EHLO and accept_8bitmime is set,
2661 Exim will have indicated that it supports the BODY=8BITMIME option. In
2662 fact, it does not support this according to the RFCs, in that it does not
2663 take any special action for forwarding messages containing 8-bit
2664 characters. That is why accept_8bitmime is not the default setting, but
2665 some sites want the action that is provided. We recognize both "8BITMIME"
2666 and "7BIT" as body types, but take no action. */
2668 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2669 (strcmpic(value, US"8BITMIME") == 0 ||
2670 strcmpic(value, US"7BIT") == 0)) {}
2672 /* Handle the AUTH extension. If the value given is not "<>" and either
2673 the ACL says "yes" or there is no ACL but the sending host is
2674 authenticated, we set it up as the authenticated sender. However, if the
2675 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2676 the condition is met. The value of AUTH is an xtext, which means that +,
2677 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2680 else if (strcmpic(name, US"AUTH") == 0)
2682 if (Ustrcmp(value, "<>") != 0)
2687 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2689 /* Put back terminator overrides for error message */
2692 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2693 US"invalid data for AUTH");
2697 if (acl_smtp_mailauth == NULL)
2699 ignore_msg = US"client not authenticated";
2700 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2704 ignore_msg = US"rejected by ACL";
2705 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2706 &user_msg, &log_msg);
2712 if (authenticated_by == NULL ||
2713 authenticated_by->mail_auth_condition == NULL ||
2714 expand_check_condition(authenticated_by->mail_auth_condition,
2715 authenticated_by->name, US"authenticator"))
2716 break; /* Accept the AUTH */
2718 ignore_msg = US"server_mail_auth_condition failed";
2719 if (authenticated_id != NULL)
2720 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2721 ignore_msg, authenticated_id);
2726 authenticated_sender = NULL;
2727 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2728 value, host_and_ident(TRUE), ignore_msg);
2731 /* Should only get DEFER or ERROR here. Put back terminator
2732 overrides for error message */
2737 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2744 /* Unknown option. Stick back the terminator characters and break
2745 the loop. An error for a malformed address will occur. */
2755 /* If we have passed the threshold for rate limiting, apply the current
2756 delay, and update it for next time, provided this is a limited host. */
2758 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2759 verify_check_host(&smtp_ratelimit_hosts) == OK)
2761 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2762 smtp_delay_mail/1000.0);
2763 millisleep((int)smtp_delay_mail);
2764 smtp_delay_mail *= smtp_rlm_factor;
2765 if (smtp_delay_mail > (double)smtp_rlm_limit)
2766 smtp_delay_mail = (double)smtp_rlm_limit;
2769 /* Now extract the address, first applying any SMTP-time rewriting. The
2770 TRUE flag allows "<>" as a sender address. */
2772 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2773 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2774 global_rewrite_rules) : smtp_data;
2776 /* rfc821_domains = TRUE; << no longer needed */
2778 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2780 /* rfc821_domains = FALSE; << no longer needed */
2782 if (raw_sender == NULL)
2784 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2788 sender_address = raw_sender;
2790 /* If there is a configured size limit for mail, check that this message
2791 doesn't exceed it. The check is postponed to this point so that the sender
2794 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2796 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2797 log_write(L_size_reject,
2798 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2799 "message too big: size%s=%d max=%d",
2801 host_and_ident(TRUE),
2802 (message_size == INT_MAX)? ">" : "",
2804 thismessage_size_limit);
2805 sender_address = NULL;
2809 /* Check there is enough space on the disk unless configured not to.
2810 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2811 plus the current message - i.e. we accept the message only if it won't
2812 reduce the space below the threshold. Add 5000 to the size to allow for
2813 overheads such as the Received: line and storing of recipients, etc.
2814 By putting the check here, even when SIZE is not given, it allow VRFY
2815 and EXPN etc. to be used when space is short. */
2817 if (!receive_check_fs(
2818 (smtp_check_spool_space && message_size >= 0)?
2819 message_size + 5000 : 0))
2821 smtp_printf("452 Space shortage, please try later\r\n");
2822 sender_address = NULL;
2826 /* If sender_address is unqualified, reject it, unless this is a locally
2827 generated message, or the sending host or net is permitted to send
2828 unqualified addresses - typically local machines behaving as MUAs -
2829 in which case just qualify the address. The flag is set above at the start
2830 of the SMTP connection. */
2832 if (sender_domain == 0 && sender_address[0] != 0)
2834 if (allow_unqualified_sender)
2836 sender_domain = Ustrlen(sender_address) + 1;
2837 sender_address = rewrite_address_qualify(sender_address, FALSE);
2838 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2843 smtp_printf("501 %s: sender address must contain a domain\r\n",
2845 log_write(L_smtp_syntax_error,
2846 LOG_MAIN|LOG_REJECT,
2847 "unqualified sender rejected: <%s> %s%s",
2849 host_and_ident(TRUE),
2851 sender_address = NULL;
2856 /* Apply an ACL check if one is defined, before responding */
2858 rc = (acl_smtp_mail == NULL)? OK :
2859 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2861 if (rc == OK || rc == DISCARD)
2863 smtp_printf("250 OK\r\n");
2864 smtp_delay_rcpt = smtp_rlr_base;
2865 recipients_discarded = (rc == DISCARD);
2866 was_rej_mail = FALSE;
2871 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2872 sender_address = NULL;
2877 /* The RCPT command requires an address as an operand. All we do
2878 here is to parse it for syntactic correctness. There may be any number
2879 of RCPT commands, specifying multiple senders. We build them all into
2880 a data structure that is in argc/argv format. The start/end values
2881 given by parse_extract_address are not used, as we keep only the
2882 extracted address. */
2888 /* There must be a sender address; if the sender was rejected and
2889 pipelining was advertised, we assume the client was pipelining, and do not
2890 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2891 get the same treatment. */
2893 if (sender_address == NULL)
2895 if (pipelining_advertised && last_was_rej_mail)
2897 smtp_printf("503 sender not yet given\r\n");
2898 was_rej_mail = TRUE;
2902 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2903 US"sender not yet given");
2904 was_rcpt = FALSE; /* Not a valid RCPT */
2910 /* Check for an operand */
2912 if (smtp_data[0] == 0)
2914 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2915 US"RCPT must have an address operand");
2920 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2921 as a recipient address */
2923 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2924 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2925 global_rewrite_rules) : smtp_data;
2927 /* rfc821_domains = TRUE; << no longer needed */
2928 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2929 &recipient_domain, FALSE);
2930 /* rfc821_domains = FALSE; << no longer needed */
2932 if (recipient == NULL)
2934 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2939 /* If the recipient address is unqualified, reject it, unless this is a
2940 locally generated message. However, unqualified addresses are permitted
2941 from a configured list of hosts and nets - typically when behaving as
2942 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2943 really. The flag is set at the start of the SMTP connection.
2945 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2946 assumed this meant "reserved local part", but the revision of RFC 821 and
2947 friends now makes it absolutely clear that it means *mailbox*. Consequently
2948 we must always qualify this address, regardless. */
2950 if (recipient_domain == 0)
2952 if (allow_unqualified_recipient ||
2953 strcmpic(recipient, US"postmaster") == 0)
2955 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2957 recipient_domain = Ustrlen(recipient) + 1;
2958 recipient = rewrite_address_qualify(recipient, TRUE);
2963 smtp_printf("501 %s: recipient address must contain a domain\r\n",
2965 log_write(L_smtp_syntax_error,
2966 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
2967 "<%s> %s%s", recipient, host_and_ident(TRUE),
2973 /* Check maximum allowed */
2975 if (rcpt_count > recipients_max && recipients_max > 0)
2977 if (recipients_max_reject)
2980 smtp_printf("552 too many recipients\r\n");
2982 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
2983 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
2988 smtp_printf("452 too many recipients\r\n");
2990 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
2991 "temporarily rejected: sender=<%s> %s", sender_address,
2992 host_and_ident(TRUE));
2999 /* If we have passed the threshold for rate limiting, apply the current
3000 delay, and update it for next time, provided this is a limited host. */
3002 if (rcpt_count > smtp_rlr_threshold &&
3003 verify_check_host(&smtp_ratelimit_hosts) == OK)
3005 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3006 smtp_delay_rcpt/1000.0);
3007 millisleep((int)smtp_delay_rcpt);
3008 smtp_delay_rcpt *= smtp_rlr_factor;
3009 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3010 smtp_delay_rcpt = (double)smtp_rlr_limit;
3013 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3014 for them. Otherwise, check the access control list for this recipient. */
3016 rc = recipients_discarded? DISCARD :
3017 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3019 /* The ACL was happy */
3023 smtp_printf("250 Accepted\r\n");
3024 receive_add_recipient(recipient, -1);
3027 /* The recipient was discarded */
3029 else if (rc == DISCARD)
3031 smtp_printf("250 Accepted\r\n");
3034 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3035 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3036 (sender_address_unrewritten != NULL)?
3037 sender_address_unrewritten : sender_address,
3038 smtp_data, recipients_discarded? "MAIL" : "RCPT",
3039 (log_msg == NULL)? US"" : US": ",
3040 (log_msg == NULL)? US"" : log_msg);
3043 /* Either the ACL failed the address, or it was deferred. */
3047 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3048 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3053 /* The DATA command is legal only if it follows successful MAIL FROM
3054 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3055 not counted as a protocol error if it follows RCPT (which must have been
3056 rejected if there are no recipients.) This function is complete when a
3057 valid DATA command is encountered.
3059 Note concerning the code used: RFC 2821 says this:
3061 - If there was no MAIL, or no RCPT, command, or all such commands
3062 were rejected, the server MAY return a "command out of sequence"
3063 (503) or "no valid recipients" (554) reply in response to the
3066 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3067 because it is the same whether pipelining is in use or not. */
3070 if (!discarded && recipients_count <= 0)
3072 if (pipelining_advertised && last_was_rcpt)
3073 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3075 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3076 US"valid RCPT command must precede DATA");
3080 if (toomany && recipients_max_reject)
3082 sender_address = NULL; /* This will allow a new MAIL without RSET */
3083 sender_address_unrewritten = NULL;
3084 smtp_printf("554 Too many recipients\r\n");
3088 if (acl_smtp_predata == NULL) rc = OK; else
3090 enable_dollar_recipients = TRUE;
3091 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3093 enable_dollar_recipients = FALSE;
3098 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3100 message_ended = END_NOTENDED; /* Indicate in middle of data */
3103 /* Either the ACL failed the address, or it was deferred. */
3106 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3112 rc = acl_check(ACL_WHERE_VRFY, smtp_data, acl_smtp_vrfy, &user_msg,
3115 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3121 /* rfc821_domains = TRUE; << no longer needed */
3122 address = parse_extract_address(smtp_data, &errmess, &start, &end,
3123 &recipient_domain, FALSE);
3124 /* rfc821_domains = FALSE; << no longer needed */
3126 if (address == NULL)
3127 s = string_sprintf("501 %s", errmess);
3130 address_item *addr = deliver_make_addr(address, FALSE);
3131 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3132 -1, -1, NULL, NULL, NULL))
3135 s = string_sprintf("250 <%s> is deliverable", address);
3139 s = (addr->message != NULL)?
3140 string_sprintf("451 <%s> %s", address, addr->message) :
3141 string_sprintf("451 Cannot resolve <%s> at this time", address);
3145 s = (addr->message != NULL)?
3146 string_sprintf("550 <%s> %s", address, addr->message) :
3147 string_sprintf("550 <%s> is not deliverable", address);
3148 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3149 smtp_data, host_and_ident(TRUE));
3154 smtp_printf("%s\r\n", s);
3160 rc = acl_check(ACL_WHERE_EXPN, smtp_data, acl_smtp_expn, &user_msg,
3163 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3166 BOOL save_log_testing_mode = log_testing_mode;
3167 address_test_mode = log_testing_mode = TRUE;
3168 (void) verify_address(deliver_make_addr(smtp_data, FALSE), smtp_out,
3169 vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1, NULL, NULL,
3171 address_test_mode = FALSE;
3172 log_testing_mode = save_log_testing_mode; /* true for -bh */
3180 if (!tls_advertised)
3182 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3183 US"STARTTLS command used when not advertised");
3187 /* Apply an ACL check if one is defined */
3189 if (acl_smtp_starttls != NULL)
3191 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3195 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3200 /* RFC 2487 is not clear on when this command may be sent, though it
3201 does state that all information previously obtained from the client
3202 must be discarded if a TLS session is started. It seems reasonble to
3203 do an implied RSET when STARTTLS is received. */
3205 incomplete_transaction_log(US"STARTTLS");
3206 smtp_reset(reset_point);
3208 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3210 /* Attempt to start up a TLS session, and if successful, discard all
3211 knowledge that was obtained previously. At least, that's what the RFC says,
3212 and that's what happens by default. However, in order to work round YAEB,
3213 there is an option to remember the esmtp state. Sigh.
3215 We must allow for an extra EHLO command and an extra AUTH command after
3216 STARTTLS that don't add to the nonmail command count. */
3218 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3220 if (!tls_remember_esmtp)
3221 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3222 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3223 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3224 if (sender_helo_name != NULL)
3226 store_free(sender_helo_name);
3227 sender_helo_name = NULL;
3228 host_build_sender_fullhost(); /* Rebuild */
3229 set_process_info("handling incoming TLS connection from %s",
3230 host_and_ident(FALSE));
3232 received_protocol = (esmtp?
3233 protocols[pextend + pcrpted +
3234 ((sender_host_authenticated != NULL)? pauthed : 0)]
3236 protocols[pnormal + pcrpted])
3238 ((sender_host_address != NULL)? pnlocal : 0);
3240 sender_host_authenticated = NULL;
3241 authenticated_id = NULL;
3242 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3243 DEBUG(D_tls) debug_printf("TLS active\n");
3244 break; /* Successful STARTTLS */
3247 /* Some local configuration problem was discovered before actually trying
3248 to do a TLS handshake; give a temporary error. */
3250 else if (rc == DEFER)
3252 smtp_printf("454 TLS currently unavailable\r\n");
3256 /* Hard failure. Reject everything except QUIT or closed connection. One
3257 cause for failure is a nested STARTTLS, in which case tls_active remains
3258 set, but we must still reject all incoming commands. */
3260 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3263 switch(smtp_read_command(FALSE))
3266 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3267 smtp_get_connection_info());
3272 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3273 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3274 smtp_get_connection_info());
3279 smtp_printf("554 Security failure\r\n");
3288 /* The ACL for QUIT is provided for gathering statistical information or
3289 similar; it does not affect the response code, but it can supply a custom
3293 incomplete_transaction_log(US"QUIT");
3295 if (acl_smtp_quit != NULL)
3297 rc = acl_check(ACL_WHERE_QUIT, US"", acl_smtp_quit,&user_msg,&log_msg);
3299 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3302 else user_msg = NULL;
3304 if (user_msg == NULL)
3305 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3307 smtp_printf("221 %s\r\n", user_msg);
3314 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3315 smtp_get_connection_info());
3320 incomplete_transaction_log(US"RSET");
3321 smtp_reset(reset_point);
3323 smtp_printf("250 Reset OK\r\n");
3324 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3329 smtp_printf("250 OK\r\n");
3333 /* Show ETRN/EXPN/VRFY if there's
3334 an ACL for checking hosts; if actually used, a check will be done for
3338 smtp_printf("214-Commands supported:\r\n");
3342 Ustrcat(buffer, " AUTH");
3344 Ustrcat(buffer, " STARTTLS");
3346 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3347 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3348 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3349 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3350 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3351 smtp_printf("214%s\r\n", buffer);
3357 incomplete_transaction_log(US"connection lost");
3358 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3360 /* Don't log by default unless in the middle of a message, as some mailers
3361 just drop the call rather than sending QUIT, and it clutters up the logs.
3364 if (sender_address != NULL || recipients_count > 0)
3365 log_write(L_lost_incoming_connection,
3367 "unexpected %s while reading SMTP command from %s%s",
3368 sender_host_unknown? "EOF" : "disconnection",
3369 host_and_ident(FALSE), smtp_read_error);
3371 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3372 smtp_get_connection_info(), smtp_read_error);
3379 if (sender_address != NULL)
3381 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3382 US"ETRN is not permitted inside a transaction");
3386 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_data,
3387 host_and_ident(FALSE));
3389 rc = acl_check(ACL_WHERE_ETRN, smtp_data, acl_smtp_etrn, &user_msg,
3393 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3397 /* Compute the serialization key for this command. */
3399 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_data);
3401 /* If a command has been specified for running as a result of ETRN, we
3402 permit any argument to ETRN. If not, only the # standard form is permitted,
3403 since that is strictly the only kind of ETRN that can be implemented
3404 according to the RFC. */
3406 if (smtp_etrn_command != NULL)
3410 etrn_command = smtp_etrn_command;
3411 deliver_domain = smtp_data;
3412 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3413 US"ETRN processing", &error);
3414 deliver_domain = NULL;
3417 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3419 smtp_printf("458 Internal failure\r\n");
3424 /* Else set up to call Exim with the -R option. */
3428 if (*smtp_data++ != '#')
3430 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3431 US"argument must begin with #");
3434 etrn_command = US"exim -R";
3435 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3439 /* If we are host-testing, don't actually do anything. */
3445 debug_printf("ETRN command is: %s\n", etrn_command);
3446 debug_printf("ETRN command execution skipped\n");
3448 smtp_printf("250 OK\r\n");
3453 /* If ETRN queue runs are to be serialized, check the database to
3454 ensure one isn't already running. */
3456 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3458 smtp_printf("458 Already processing %s\r\n", smtp_data);
3462 /* Fork a child process and run the command. We don't want to have to
3463 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3464 forking. It should be set that way anyway for external incoming SMTP,
3465 but we save and restore to be tidy. If serialization is required, we
3466 actually run the command in yet another process, so we can wait for it
3467 to complete and then remove the serialization lock. */
3469 oldsignal = signal(SIGCHLD, SIG_IGN);
3471 if ((pid = fork()) == 0)
3473 smtp_input = FALSE; /* This process is not associated with the */
3474 fclose(smtp_in); /* SMTP call any more. */
3477 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3479 /* If not serializing, do the exec right away. Otherwise, fork down
3480 into another process. */
3482 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3484 DEBUG(D_exec) debug_print_argv(argv);
3485 exim_nullstd(); /* Ensure std{in,out,err} exist */
3486 execv(CS argv[0], (char *const *)argv);
3487 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3488 etrn_command, strerror(errno));
3489 _exit(EXIT_FAILURE); /* paranoia */
3492 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3493 is, we are in the first subprocess, after forking again. All we can do
3494 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3495 complete, before removing the serialization. */
3498 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3499 "failed: %s", strerror(errno));
3503 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3505 (void)wait(&status);
3506 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3510 enq_end(etrn_serialize_key);
3511 _exit(EXIT_SUCCESS);
3514 /* Back in the top level SMTP process. Check that we started a subprocess
3515 and restore the signal state. */
3519 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3521 smtp_printf("458 Unable to fork process\r\n");
3522 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3524 else smtp_printf("250 OK\r\n");
3526 signal(SIGCHLD, oldsignal);
3531 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3532 US"unexpected argument data");
3536 /* This currently happens only for NULLs, but could be extended. */
3539 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3540 US"NULL character(s) present (shown as '?')");
3541 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3546 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3547 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3548 c = smtp_inend - smtp_inptr;
3549 if (c > 150) c = 150;
3551 incomplete_transaction_log(US"sync failure");
3552 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: "
3553 "synchronization error "
3554 "(next input sent too soon: pipelining was%s advertised): "
3555 "rejected \"%s\" %s next input=\"%s\"",
3556 pipelining_advertised? "" : " not",
3557 cmd_buffer, host_and_ident(TRUE),
3558 string_printing(smtp_inptr));
3559 smtp_printf("554 SMTP synchronization error\r\n");
3560 done = 1; /* Pretend eof - drops connection */
3564 case TOO_MANY_NONMAIL_CMD:
3565 incomplete_transaction_log(US"too many non-mail commands");
3566 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3567 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
3568 smtp_data - cmd_buffer, cmd_buffer);
3569 smtp_printf("554 Too many nonmail commands\r\n");
3570 done = 1; /* Pretend eof - drops connection */
3575 if (unknown_command_count++ >= smtp_max_unknown_commands)
3577 log_write(L_smtp_syntax_error, LOG_MAIN,
3578 "SMTP syntax error in \"%s\" %s %s",
3579 string_printing(cmd_buffer), host_and_ident(TRUE),
3580 US"unrecognized command");
3581 incomplete_transaction_log(US"unrecognized command");
3582 smtp_printf("500 Too many unrecognized commands\r\n");
3584 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3585 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3589 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3590 US"unrecognized command");
3594 /* This label is used by goto's inside loops that want to break out to
3595 the end of the command-processing loop. */
3598 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3599 last_was_rcpt = was_rcpt; /* protocol error handling */
3603 return done - 2; /* Convert yield values */
3606 /* End of smtp_in.c */