1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.27 2005/12/12 15:58:53 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 smtp_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 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
123 final fields of all except AUTH are forced TRUE at the start of a new message
124 setup, to allow one of each between messages that is not counted as a nonmail
125 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
126 allow a new EHLO after starting up TLS.
128 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
129 counted. However, the flag is changed when AUTH is received, so that multiple
130 failing AUTHs will eventually hit the limit. After a successful AUTH, another
131 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
132 forced TRUE, to allow for the re-authentication that can happen at that point.
134 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
135 count of non-mail commands and possibly provoke an error. */
137 static smtp_cmd_list cmd_list[] = {
138 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
139 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
140 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
141 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
143 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
146 /* If you change anything above here, also fix the definitions below. */
148 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
149 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
150 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
151 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
152 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
153 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
154 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
155 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
156 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
159 static smtp_cmd_list *cmd_list_end =
160 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
162 #define CMD_LIST_RSET 0
163 #define CMD_LIST_HELO 1
164 #define CMD_LIST_EHLO 2
165 #define CMD_LIST_AUTH 3
166 #define CMD_LIST_STARTTLS 4
168 static uschar *protocols[] = {
169 US"local-smtp", /* HELO */
170 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
171 US"local-esmtp", /* EHLO */
172 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
173 US"local-esmtpa", /* EHLO->AUTH */
174 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
179 #define pcrpted 1 /* added to pextend or pnormal */
180 #define pauthed 2 /* added to pextend */
181 #define pnlocal 6 /* offset to remove "local" */
183 /* When reading SMTP from a remote host, we have to use our own versions of the
184 C input-reading functions, in order to be able to flush the SMTP output only
185 when about to read more data from the socket. This is the only way to get
186 optimal performance when the client is using pipelining. Flushing for every
187 command causes a separate packet and reply packet each time; saving all the
188 responses up (when pipelining) combines them into one packet and one response.
190 For simplicity, these functions are used for *all* SMTP input, not only when
191 receiving over a socket. However, after setting up a secure socket (SSL), input
192 is read via the OpenSSL library, and another set of functions is used instead
195 These functions are set in the receive_getc etc. variables and called with the
196 same interface as the C functions. However, since there can only ever be
197 one incoming SMTP call, we just use a single buffer and flags. There is no need
198 to implement a complicated private FILE-like structure.*/
200 static uschar *smtp_inbuffer;
201 static uschar *smtp_inptr;
202 static uschar *smtp_inend;
203 static int smtp_had_eof;
204 static int smtp_had_error;
207 /*************************************************
208 * SMTP version of getc() *
209 *************************************************/
211 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
212 it flushes the output, and refills the buffer, with a timeout. The signal
213 handler is set appropriately by the calling function. This function is not used
214 after a connection has negotated itself into an TLS/SSL state.
217 Returns: the next character or EOF
223 if (smtp_inptr >= smtp_inend)
227 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
228 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
233 /* Must put the error text in fixed store, because this might be during
234 header reading, where it releases unused store above the header. */
237 smtp_had_error = save_errno;
238 smtp_read_error = string_copy_malloc(
239 string_sprintf(" (error: %s)", strerror(save_errno)));
241 else smtp_had_eof = 1;
244 smtp_inend = smtp_inbuffer + rc;
245 smtp_inptr = smtp_inbuffer;
247 return *smtp_inptr++;
252 /*************************************************
253 * SMTP version of ungetc() *
254 *************************************************/
256 /* Puts a character back in the input buffer. Only ever
262 Returns: the character
268 *(--smtp_inptr) = ch;
275 /*************************************************
276 * SMTP version of feof() *
277 *************************************************/
279 /* Tests for a previous EOF
282 Returns: non-zero if the eof flag is set
294 /*************************************************
295 * SMTP version of ferror() *
296 *************************************************/
298 /* Tests for a previous read error, and returns with errno
299 restored to what it was when the error was detected.
302 Returns: non-zero if the error flag is set
308 errno = smtp_had_error;
309 return smtp_had_error;
315 /*************************************************
316 * Write formatted string to SMTP channel *
317 *************************************************/
319 /* This is a separate function so that we don't have to repeat everything for
320 TLS support or debugging. It is global so that the daemon and the
321 authentication functions can use it. It does not return any error indication,
322 because major problems such as dropped connections won't show up till an output
323 flush for non-TLS connections. The smtp_fflush() function is available for
324 checking that: for convenience, TLS output errors are remembered here so that
325 they are also picked up later by smtp_fflush().
329 ... optional arguments
335 smtp_printf(char *format, ...)
341 va_start(ap, format);
342 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
343 debug_printf("SMTP>> %s", big_buffer);
346 va_start(ap, format);
348 /* If in a TLS session we have to format the string, and then write it using a
354 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
356 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
357 smtp_closedown(US"Unexpected error");
358 exim_exit(EXIT_FAILURE);
360 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
365 /* Otherwise, just use the standard library function. */
367 if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
373 /*************************************************
374 * Flush SMTP out and check for error *
375 *************************************************/
377 /* This function isn't currently used within Exim (it detects errors when it
378 tries to read the next SMTP input), but is available for use in local_scan().
379 For non-TLS connections, it flushes the output and checks for errors. For
380 TLS-connections, it checks for a previously-detected TLS write error.
383 Returns: 0 for no error; -1 after an error
389 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
390 return smtp_write_error;
395 /*************************************************
396 * SMTP command read timeout *
397 *************************************************/
399 /* Signal handler for timing out incoming SMTP commands. This attempts to
402 Argument: signal number (SIGALRM)
407 command_timeout_handler(int sig)
409 sig = sig; /* Keep picky compilers happy */
410 log_write(L_lost_incoming_connection,
411 LOG_MAIN, "SMTP command timeout on%s connection from %s",
412 (tls_active >= 0)? " TLS" : "",
413 host_and_ident(FALSE));
414 if (smtp_batched_input)
415 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
416 smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
417 smtp_active_hostname);
419 exim_exit(EXIT_FAILURE);
424 /*************************************************
426 *************************************************/
428 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
430 Argument: signal number (SIGTERM)
435 command_sigterm_handler(int sig)
437 sig = sig; /* Keep picky compilers happy */
438 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
439 if (smtp_batched_input)
440 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
441 smtp_printf("421 %s: Service not available - closing connection\r\n",
442 smtp_active_hostname);
443 exim_exit(EXIT_FAILURE);
448 /*************************************************
449 * Read one command line *
450 *************************************************/
452 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
453 There are sites that don't do this, and in any case internal SMTP probably
454 should check only for LF. Consequently, we check here for LF only. The line
455 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
456 an unknown command. The command is read into the global smtp_cmd_buffer so that
457 it is available via $smtp_command.
459 The character reading routine sets up a timeout for each block actually read
460 from the input (which may contain more than one command). We set up a special
461 signal handler that closes down the session on a timeout. Control does not
465 check_sync if TRUE, check synchronization rules if global option is TRUE
467 Returns: a code identifying the command (enumerated above)
471 smtp_read_command(BOOL check_sync)
476 BOOL hadnull = FALSE;
478 os_non_restarting_signal(SIGALRM, command_timeout_handler);
480 while ((c = (receive_getc)()) != '\n' && c != EOF)
482 if (ptr >= smtp_cmd_buffer_size)
484 os_non_restarting_signal(SIGALRM, sigalrm_handler);
492 smtp_cmd_buffer[ptr++] = c;
495 receive_linecount++; /* For BSMTP errors */
496 os_non_restarting_signal(SIGALRM, sigalrm_handler);
498 /* If hit end of file, return pseudo EOF command. Whether we have a
499 part-line already read doesn't matter, since this is an error state. */
501 if (c == EOF) return EOF_CMD;
503 /* Remove any CR and white space at the end of the line, and terminate the
506 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
507 smtp_cmd_buffer[ptr] = 0;
509 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
511 /* NULLs are not allowed in SMTP commands */
513 if (hadnull) return BADCHAR_CMD;
515 /* Scan command list and return identity, having set the data pointer
516 to the start of the actual data characters. Check for SMTP synchronization
519 for (p = cmd_list; p < cmd_list_end; p++)
521 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0)
523 if (smtp_inptr < smtp_inend && /* Outstanding input */
524 p->cmd < sync_cmd_limit && /* Command should sync */
525 check_sync && /* Local flag set */
526 smtp_enforce_sync && /* Global flag set */
527 sender_host_address != NULL && /* Not local input */
528 !sender_host_notsocket) /* Really is a socket */
531 /* Point after the command, but don't skip over leading spaces till after
532 the following test, so that if it fails, the command name can easily be
535 smtp_cmd_argument = smtp_cmd_buffer + p->len;
537 /* Count non-mail commands from those hosts that are controlled in this
538 way. The default is all hosts. We don't waste effort checking the list
539 until we get a non-mail command, but then cache the result to save checking
540 again. If there's a DEFER while checking the host, assume it's in the list.
542 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
543 start of each incoming message by fiddling with the value in the table. */
547 if (count_nonmail == TRUE_UNSET) count_nonmail =
548 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
549 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
550 return TOO_MANY_NONMAIL_CMD;
553 /* Get the data pointer over leading spaces and return; if there is data
554 for a command that does not expect it, give the error centrally here. */
556 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
557 return (p->has_arg || *smtp_cmd_argument == 0)? p->cmd : BADARG_CMD;
561 /* Enforce synchronization for unknown commands */
563 if (smtp_inptr < smtp_inend && /* Outstanding input */
564 check_sync && /* Local flag set */
565 smtp_enforce_sync && /* Global flag set */
566 sender_host_address != NULL && /* Not local input */
567 !sender_host_notsocket) /* Really is a socket */
575 /*************************************************
576 * Forced closedown of call *
577 *************************************************/
579 /* This function is called from log.c when Exim is dying because of a serious
580 disaster, and also from some other places. If an incoming non-batched SMTP
581 channel is open, it swallows the rest of the incoming message if in the DATA
582 phase, sends the reply string, and gives an error to all subsequent commands
583 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
586 Argument: SMTP reply string to send, excluding the code
591 smtp_closedown(uschar *message)
593 if (smtp_in == NULL || smtp_batched_input) return;
594 receive_swallow_smtp();
595 smtp_printf("421 %s\r\n", message);
599 switch(smtp_read_command(FALSE))
605 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
610 smtp_printf("250 Reset OK\r\n");
614 smtp_printf("421 %s\r\n", message);
623 /*************************************************
624 * Set up connection info for logging *
625 *************************************************/
627 /* This function is called when logging information about an SMTP connection.
628 It sets up appropriate source information, depending on the type of connection.
631 Returns: a string describing the connection
635 smtp_get_connection_info(void)
638 return string_sprintf("SMTP connection from %s", sender_fullhost);
640 if (sender_host_unknown || sender_host_notsocket)
641 return string_sprintf("SMTP connection from %s", sender_ident);
644 return string_sprintf("SMTP connection from %s (via inetd)", sender_fullhost);
646 if ((log_extra_selector & LX_incoming_interface) != 0 &&
647 interface_address != NULL)
648 return string_sprintf("SMTP connection from %s I=[%s]:%d", sender_fullhost,
649 interface_address, interface_port);
651 return string_sprintf("SMTP connection from %s", sender_fullhost);
656 /*************************************************
657 * Check HELO line and set sender_helo_name *
658 *************************************************/
660 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
661 the domain name of the sending host, or an ip literal in square brackets. The
662 arrgument is placed in sender_helo_name, which is in malloc store, because it
663 must persist over multiple incoming messages. If helo_accept_junk is set, this
664 host is permitted to send any old junk (needed for some broken hosts).
665 Otherwise, helo_allow_chars can be used for rogue characters in general
666 (typically people want to let in underscores).
669 s the data portion of the line (already past any white space)
671 Returns: TRUE or FALSE
675 check_helo(uschar *s)
678 uschar *end = s + Ustrlen(s);
679 BOOL yield = helo_accept_junk;
681 /* Discard any previous helo name */
683 if (sender_helo_name != NULL)
685 store_free(sender_helo_name);
686 sender_helo_name = NULL;
689 /* Skip tests if junk is permitted. */
693 /* Allow the new standard form for IPv6 address literals, namely,
694 [IPv6:....], and because someone is bound to use it, allow an equivalent
695 IPv4 form. Allow plain addresses as well. */
702 if (strncmpic(s, US"[IPv6:", 6) == 0)
703 yield = (string_is_ip_address(s+6, NULL) == 6);
704 else if (strncmpic(s, US"[IPv4:", 6) == 0)
705 yield = (string_is_ip_address(s+6, NULL) == 4);
707 yield = (string_is_ip_address(s+1, NULL) != 0);
712 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
713 that have been configured (usually underscore - sigh). */
720 if (!isalnum(*s) && *s != '.' && *s != '-' &&
721 Ustrchr(helo_allow_chars, *s) == NULL)
731 /* Save argument if OK */
733 if (yield) sender_helo_name = string_copy_malloc(start);
741 /*************************************************
742 * Extract SMTP command option *
743 *************************************************/
745 /* This function picks the next option setting off the end of smtp_cmd_argument. It
746 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
747 things that can appear there.
750 name point this at the name
751 value point this at the data string
753 Returns: TRUE if found an option
757 extract_option(uschar **name, uschar **value)
760 uschar *v = smtp_cmd_argument + Ustrlen(smtp_cmd_argument) -1;
761 while (isspace(*v)) v--;
764 while (v > smtp_cmd_argument && *v != '=' && !isspace(*v)) v--;
765 if (*v != '=') return FALSE;
768 while(isalpha(n[-1])) n--;
770 if (n[-1] != ' ') return FALSE;
785 /*************************************************
786 * Reset for new message *
787 *************************************************/
789 /* This function is called whenever the SMTP session is reset from
790 within either of the setup functions.
792 Argument: the stacking pool storage reset point
797 smtp_reset(void *reset_point)
800 store_reset(reset_point);
801 recipients_list = NULL;
802 rcpt_count = rcpt_defer_count = rcpt_fail_count =
803 raw_recipients_count = recipients_count = recipients_list_max = 0;
804 message_linecount = 0;
806 acl_warn_headers = NULL;
807 queue_only_policy = FALSE;
808 deliver_freeze = FALSE; /* Can be set by ACL */
809 fake_response = OK; /* Can be set by ACL */
810 #ifdef WITH_CONTENT_SCAN
811 no_mbox_unspool = FALSE; /* Can be set by ACL */
813 submission_mode = FALSE; /* Can be set by ACL */
814 suppress_local_fixups = FALSE; /* Can be set by ACL */
815 active_local_from_check = local_from_check; /* Can be set by ACL */
816 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
817 sender_address = NULL;
818 submission_name = NULL; /* Can be set by ACL */
819 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
820 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
821 sender_verified_list = NULL; /* No senders verified */
822 memset(sender_address_cache, 0, sizeof(sender_address_cache));
823 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
824 authenticated_sender = NULL;
825 #ifdef EXPERIMENTAL_BRIGHTMAIL
829 #ifdef EXPERIMENTAL_DOMAINKEYS
832 #ifdef EXPERIMENTAL_SPF
833 spf_header_comment = NULL;
836 spf_smtp_comment = NULL;
838 body_linecount = body_zerocount = 0;
840 sender_rate = sender_rate_limit = sender_rate_period = NULL;
841 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
842 /* Note that ratelimiters_conn persists across resets. */
844 /* The message variables follow the connection variables. */
846 for (i = 0; i < ACL_MVARS; i++) acl_var[ACL_CVARS + i] = NULL;
848 /* The message body variables use malloc store. They may be set if this is
849 not the first message in an SMTP session and the previous message caused them
850 to be referenced in an ACL. */
852 if (message_body != NULL)
854 store_free(message_body);
858 if (message_body_end != NULL)
860 store_free(message_body_end);
861 message_body_end = NULL;
864 /* Warning log messages are also saved in malloc store. They are saved to avoid
865 repetition in the same message, but it seems right to repeat them for different
868 while (acl_warn_logged != NULL)
870 string_item *this = acl_warn_logged;
871 acl_warn_logged = acl_warn_logged->next;
880 /*************************************************
881 * Initialize for incoming batched SMTP message *
882 *************************************************/
884 /* This function is called from smtp_setup_msg() in the case when
885 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
886 of messages in one file with SMTP commands between them. All errors must be
887 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
888 relevant. After an error on a sender, or an invalid recipient, the remainder
889 of the message is skipped. The value of received_protocol is already set.
892 Returns: > 0 message successfully started (reached DATA)
893 = 0 QUIT read or end of file reached
898 smtp_setup_batch_msg(void)
901 void *reset_point = store_get(0);
903 /* Save the line count at the start of each transaction - single commands
904 like HELO and RSET count as whole transactions. */
906 bsmtp_transaction_linecount = receive_linecount;
908 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
910 smtp_reset(reset_point); /* Reset for start of message */
912 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
913 value. The values are 2 larger than the required yield of the function. */
918 uschar *recipient = NULL;
919 int start, end, sender_domain, recipient_domain;
921 switch(smtp_read_command(FALSE))
923 /* The HELO/EHLO commands set sender_address_helo if they have
924 valid data; otherwise they are ignored, except that they do
925 a reset of the state. */
930 check_helo(smtp_cmd_argument);
934 smtp_reset(reset_point);
935 bsmtp_transaction_linecount = receive_linecount;
939 /* The MAIL FROM command requires an address as an operand. All we
940 do here is to parse it for syntactic correctness. The form "<>" is
941 a special case which converts into an empty string. The start/end
942 pointers in the original are not used further for this address, as
943 it is the canonical extracted address which is all that is kept. */
946 if (sender_address != NULL)
947 /* The function moan_smtp_batch() does not return. */
948 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
950 if (smtp_cmd_argument[0] == 0)
951 /* The function moan_smtp_batch() does not return. */
952 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
954 /* Reset to start of message */
956 smtp_reset(reset_point);
958 /* Apply SMTP rewrite */
960 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
961 rewrite_one(smtp_cmd_argument, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
962 US"", global_rewrite_rules) : smtp_cmd_argument;
964 /* Extract the address; the TRUE flag allows <> as valid */
967 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
970 if (raw_sender == NULL)
971 /* The function moan_smtp_batch() does not return. */
972 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
974 sender_address = string_copy(raw_sender);
976 /* Qualify unqualified sender addresses if permitted to do so. */
978 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
980 if (allow_unqualified_sender)
982 sender_address = rewrite_address_qualify(sender_address, FALSE);
983 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
984 "and rewritten\n", raw_sender);
986 /* The function moan_smtp_batch() does not return. */
987 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
993 /* The RCPT TO command requires an address as an operand. All we do
994 here is to parse it for syntactic correctness. There may be any number
995 of RCPT TO commands, specifying multiple senders. We build them all into
996 a data structure that is in argc/argv format. The start/end values
997 given by parse_extract_address are not used, as we keep only the
998 extracted address. */
1001 if (sender_address == NULL)
1002 /* The function moan_smtp_batch() does not return. */
1003 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1005 if (smtp_cmd_argument[0] == 0)
1006 /* The function moan_smtp_batch() does not return. */
1007 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1009 /* Check maximum number allowed */
1011 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1012 /* The function moan_smtp_batch() does not return. */
1013 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1014 recipients_max_reject? "552": "452");
1016 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1017 recipient address */
1019 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1020 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
1021 global_rewrite_rules) : smtp_cmd_argument;
1023 /* rfc821_domains = TRUE; << no longer needed */
1024 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1025 &recipient_domain, FALSE);
1026 /* rfc821_domains = FALSE; << no longer needed */
1028 if (recipient == NULL)
1029 /* The function moan_smtp_batch() does not return. */
1030 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1032 /* If the recipient address is unqualified, qualify it if permitted. Then
1033 add it to the list of recipients. */
1035 if (recipient_domain == 0)
1037 if (allow_unqualified_recipient)
1039 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1041 recipient = rewrite_address_qualify(recipient, TRUE);
1043 /* The function moan_smtp_batch() does not return. */
1044 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1047 receive_add_recipient(recipient, -1);
1051 /* The DATA command is legal only if it follows successful MAIL FROM
1052 and RCPT TO commands. This function is complete when a valid DATA
1053 command is encountered. */
1056 if (sender_address == NULL || recipients_count <= 0)
1058 /* The function moan_smtp_batch() does not return. */
1059 if (sender_address == NULL)
1060 moan_smtp_batch(smtp_cmd_buffer,
1061 "503 MAIL FROM:<sender> command must precede DATA");
1063 moan_smtp_batch(smtp_cmd_buffer,
1064 "503 RCPT TO:<recipient> must precede DATA");
1068 done = 3; /* DATA successfully achieved */
1069 message_ended = END_NOTENDED; /* Indicate in middle of message */
1074 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1081 bsmtp_transaction_linecount = receive_linecount;
1092 /* The function moan_smtp_batch() does not return. */
1093 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1098 /* The function moan_smtp_batch() does not return. */
1099 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1104 /* The function moan_smtp_batch() does not return. */
1105 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1110 return done - 2; /* Convert yield values */
1116 /*************************************************
1117 * Start an SMTP session *
1118 *************************************************/
1120 /* This function is called at the start of an SMTP session. Thereafter,
1121 smtp_setup_msg() is called to initiate each separate message. This
1122 function does host-specific testing, and outputs the banner line.
1125 Returns: FALSE if the session can not continue; something has
1126 gone wrong, or the connection to the host is blocked
1130 smtp_start_session(void)
1136 /* If we are running in the test harness, and the incoming call is from
1137 127.0.0.2 (sic), have a short delay. This makes it possible to test handling of
1138 input sent too soon (before the banner is output). */
1140 if (running_in_test_harness &&
1141 sender_host_address != NULL &&
1142 Ustrcmp(sender_host_address, "127.0.0.2") == 0)
1145 /* Default values for certain variables */
1147 helo_seen = esmtp = helo_accept_junk = FALSE;
1148 count_nonmail = TRUE_UNSET;
1149 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1150 smtp_delay_mail = smtp_rlm_base;
1151 auth_advertised = FALSE;
1152 pipelining_advertised = FALSE;
1153 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1155 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1157 sender_host_authenticated = NULL;
1158 authenticated_by = NULL;
1161 tls_cipher = tls_peerdn = NULL;
1162 tls_advertised = FALSE;
1165 /* Reset ACL connection variables */
1167 for (i = 0; i < ACL_CVARS; i++) acl_var[i] = NULL;
1169 /* Allow for trailing 0 in the command buffer. */
1171 smtp_cmd_buffer = (uschar *)malloc(smtp_cmd_buffer_size + 1);
1172 if (smtp_cmd_buffer == NULL)
1173 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1174 "malloc() failed for SMTP command buffer");
1176 /* For batched input, the protocol setting can be overridden from the
1177 command line by a trusted caller. */
1179 if (smtp_batched_input)
1181 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1184 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1185 reset later if any of EHLO/AUTH/STARTTLS are received. */
1189 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1191 /* Set up the buffer for inputting using direct read() calls, and arrange to
1192 call the local functions instead of the standard C ones. */
1194 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1195 if (smtp_inbuffer == NULL)
1196 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1197 receive_getc = smtp_getc;
1198 receive_ungetc = smtp_ungetc;
1199 receive_feof = smtp_feof;
1200 receive_ferror = smtp_ferror;
1201 smtp_inptr = smtp_inend = smtp_inbuffer;
1202 smtp_had_eof = smtp_had_error = 0;
1204 /* Set up the message size limit; this may be host-specific */
1206 thismessage_size_limit = expand_string_integer(message_size_limit);
1207 if (thismessage_size_limit < 0)
1209 if (thismessage_size_limit == -1)
1210 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1211 "%s", expand_string_message);
1213 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1214 "%s", expand_string_message);
1215 smtp_closedown(US"Temporary local problem - please try later");
1219 /* When a message is input locally via the -bs or -bS options, sender_host_
1220 unknown is set unless -oMa was used to force an IP address, in which case it
1221 is checked like a real remote connection. When -bs is used from inetd, this
1222 flag is not set, causing the sending host to be checked. The code that deals
1223 with IP source routing (if configured) is never required for -bs or -bS and
1224 the flag sender_host_notsocket is used to suppress it.
1226 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1227 reserve for certain hosts and/or networks. */
1229 if (!sender_host_unknown)
1232 BOOL reserved_host = FALSE;
1234 /* Look up IP options (source routing info) on the socket if this is not an
1235 -oMa "host", and if any are found, log them and drop the connection.
1237 Linux (and others now, see below) is different to everyone else, so there
1238 has to be some conditional compilation here. Versions of Linux before 2.1.15
1239 used a structure whose name was "options". Somebody finally realized that
1240 this name was silly, and it got changed to "ip_options". I use the
1241 newer name here, but there is a fudge in the script that sets up os.h
1242 to define a macro in older Linux systems.
1244 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1245 glibc 2, which has chosen ip_opts for the structure name. This is now
1246 really a glibc thing rather than a Linux thing, so the condition name
1247 has been changed to reflect this. It is relevant also to GNU/Hurd.
1249 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1250 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1251 a special macro defined in the os.h file.
1253 Some DGUX versions on older hardware appear not to support IP options at
1254 all, so there is now a general macro which can be set to cut out this
1257 How to do this properly in IPv6 is not yet known. */
1259 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1261 #ifdef GLIBC_IP_OPTIONS
1262 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1267 #elif defined DARWIN_IP_OPTIONS
1273 if (!host_checking && !sender_host_notsocket)
1276 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1277 struct ip_options *ipopt = store_get(optlen);
1279 struct ip_opts ipoptblock;
1280 struct ip_opts *ipopt = &ipoptblock;
1281 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1283 struct ipoption ipoptblock;
1284 struct ipoption *ipopt = &ipoptblock;
1285 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1288 /* Occasional genuine failures of getsockopt() have been seen - for
1289 example, "reset by peer". Therefore, just log and give up on this
1290 call, unless the error is ENOPROTOOPT. This error is given by systems
1291 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1292 of writing. So for that error, carry on - we just can't do an IP options
1295 DEBUG(D_receive) debug_printf("checking for IP options\n");
1297 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1300 if (errno != ENOPROTOOPT)
1302 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1303 host_and_ident(FALSE), strerror(errno));
1304 smtp_printf("451 SMTP service not available\r\n");
1309 /* Deal with any IP options that are set. On the systems I have looked at,
1310 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1311 more logging data than will fit in big_buffer. Nevertheless, after somebody
1312 questioned this code, I've added in some paranoid checking. */
1314 else if (optlen > 0)
1316 uschar *p = big_buffer;
1317 uschar *pend = big_buffer + big_buffer_size;
1318 uschar *opt, *adptr;
1320 struct in_addr addr;
1323 uschar *optstart = (uschar *)(ipopt->__data);
1325 uschar *optstart = (uschar *)(ipopt->ip_opts);
1327 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1330 DEBUG(D_receive) debug_printf("IP options exist\n");
1332 Ustrcpy(p, "IP options on incoming call:");
1335 for (opt = optstart; opt != NULL &&
1336 opt < (uschar *)(ipopt) + optlen;)
1350 if (!string_format(p, pend-p, " %s [@%s",
1351 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1353 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1355 inet_ntoa(ipopt->ip_dst)))
1357 inet_ntoa(ipopt->ipopt_dst)))
1365 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1367 while (optcount-- > 0)
1369 memcpy(&addr, adptr, sizeof(addr));
1370 if (!string_format(p, pend - p - 1, "%s%s",
1371 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1377 adptr += sizeof(struct in_addr);
1386 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1389 for (i = 0; i < opt[1]; i++)
1391 sprintf(CS p, "%2.2x ", opt[i]);
1402 log_write(0, LOG_MAIN, "%s", big_buffer);
1404 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1406 log_write(0, LOG_MAIN|LOG_REJECT,
1407 "connection from %s refused (IP options)", host_and_ident(FALSE));
1409 smtp_printf("554 SMTP service not available\r\n");
1413 /* Length of options = 0 => there are no options */
1415 else DEBUG(D_receive) debug_printf("no IP options found\n");
1417 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1419 /* Set keep-alive in socket options. The option is on by default. This
1420 setting is an attempt to get rid of some hanging connections that stick in
1421 read() when the remote end (usually a dialup) goes away. */
1423 if (smtp_accept_keepalive && !sender_host_notsocket)
1424 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1426 /* If the current host matches host_lookup, set the name by doing a
1427 reverse lookup. On failure, sender_host_name will be NULL and
1428 host_lookup_failed will be TRUE. This may or may not be serious - optional
1431 if (verify_check_host(&host_lookup) == OK)
1433 (void)host_name_lookup();
1434 host_build_sender_fullhost();
1437 /* Delay this until we have the full name, if it is looked up. */
1439 set_process_info("handling incoming connection from %s",
1440 host_and_ident(FALSE));
1442 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1443 smtps port for use with older style SSL MTAs. */
1446 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1450 /* Test for explicit connection rejection */
1452 if (verify_check_host(&host_reject_connection) == OK)
1454 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1455 "from %s (host_reject_connection)", host_and_ident(FALSE));
1456 smtp_printf("554 SMTP service not available\r\n");
1460 /* Test with TCP Wrappers if so configured */
1462 #ifdef USE_TCP_WRAPPERS
1463 if (!hosts_ctl("exim",
1464 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1465 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1466 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1468 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1469 log_write(L_connection_reject,
1470 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1471 "(tcp wrappers)", host_and_ident(FALSE));
1472 smtp_printf("554 SMTP service not available\r\n");
1477 /* Check for reserved slots. Note that the count value doesn't include
1478 this process, as it gets upped in the parent process. */
1480 if (smtp_accept_max > 0 &&
1481 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1483 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1485 log_write(L_connection_reject,
1486 LOG_MAIN, "temporarily refused connection from %s: not in "
1487 "reserve list: connected=%d max=%d reserve=%d%s",
1488 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1489 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1490 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1491 "please try again later\r\n", smtp_active_hostname);
1494 reserved_host = TRUE;
1497 /* If a load level above which only messages from reserved hosts are
1498 accepted is set, check the load. For incoming calls via the daemon, the
1499 check is done in the superior process if there are no reserved hosts, to
1500 save a fork. In all cases, the load average will already be available
1501 in a global variable at this point. */
1503 if (smtp_load_reserve >= 0 &&
1504 load_average > smtp_load_reserve &&
1506 verify_check_host(&smtp_reserve_hosts) != OK)
1508 log_write(L_connection_reject,
1509 LOG_MAIN, "temporarily refused connection from %s: not in "
1510 "reserve list and load average = %.2f", host_and_ident(FALSE),
1511 (double)load_average/1000.0);
1512 smtp_printf("421 %s: Too much load; please try again later\r\n",
1513 smtp_active_hostname);
1517 /* Determine whether unqualified senders or recipients are permitted
1518 for this host. Unfortunately, we have to do this every time, in order to
1519 set the flags so that they can be inspected when considering qualifying
1520 addresses in the headers. For a site that permits no qualification, this
1521 won't take long, however. */
1523 allow_unqualified_sender =
1524 verify_check_host(&sender_unqualified_hosts) == OK;
1526 allow_unqualified_recipient =
1527 verify_check_host(&recipient_unqualified_hosts) == OK;
1529 /* Determine whether HELO/EHLO is required for this host. The requirement
1530 can be hard or soft. */
1532 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1534 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1536 /* Determine whether this hosts is permitted to send syntactic junk
1537 after a HELO or EHLO command. */
1539 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1542 /* For batch SMTP input we are now done. */
1544 if (smtp_batched_input) return TRUE;
1546 /* Run the ACL if it exists */
1548 if (acl_smtp_connect != NULL)
1551 uschar *user_msg, *log_msg;
1552 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1556 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1561 /* Output the initial message for a two-way SMTP connection. It may contain
1562 newlines, which then cause a multi-line response to be given. */
1564 s = expand_string(smtp_banner);
1566 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1567 "failed: %s", smtp_banner, expand_string_message);
1569 /* Remove any terminating newlines; might as well remove trailing space too */
1572 while (p > s && isspace(p[-1])) p--;
1575 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1576 is all contained in a single IP packet. The original code wrote out the
1577 greeting using several calls to fprint/fputc, and on busy servers this could
1578 cause it to be split over more than one packet - which caused CC:Mail to fall
1579 over when it got the second part of the greeting after sending its first
1580 command. Sigh. To try to avoid this, build the complete greeting message
1581 first, and output it in one fell swoop. This gives a better chance of it
1582 ending up as a single packet. */
1584 ss = store_get(size);
1588 do /* At least once, in case we have an empty string */
1591 uschar *linebreak = Ustrchr(p, '\n');
1592 if (linebreak == NULL)
1595 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1599 len = linebreak - p;
1600 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1602 ss = string_cat(ss, &size, &ptr, p, len);
1603 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1605 if (linebreak != NULL) p++;
1609 ss[ptr] = 0; /* string_cat leaves room for this */
1611 /* Before we write the banner, check that there is no input pending, unless
1612 this synchronisation check is disabled. */
1614 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1617 struct timeval tzero;
1621 FD_SET(fileno(smtp_in), &fds);
1622 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1625 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1628 if (rc > 150) rc = 150;
1629 smtp_inbuffer[rc] = 0;
1630 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1631 "synchronization error (input sent without waiting for greeting): "
1632 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1633 string_printing(smtp_inbuffer));
1634 smtp_printf("554 SMTP synchronization error\r\n");
1640 /* Now output the banner */
1642 smtp_printf("%s", ss);
1650 /*************************************************
1651 * Handle SMTP syntax and protocol errors *
1652 *************************************************/
1654 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1655 to do so. Then transmit the error response. The return value depends on the
1656 number of syntax and protocol errors in this SMTP session.
1659 type error type, given as a log flag bit
1660 code response code; <= 0 means don't send a response
1661 data data to reflect in the response (can be NULL)
1662 errmess the error message
1664 Returns: -1 limit of syntax/protocol errors NOT exceeded
1665 +1 limit of syntax/protocol errors IS exceeded
1667 These values fit in with the values of the "done" variable in the main
1668 processing loop in smtp_setup_msg(). */
1671 synprot_error(int type, int code, uschar *data, uschar *errmess)
1675 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1676 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1677 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1679 if (++synprot_error_count > smtp_max_synprot_errors)
1682 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1683 "syntax or protocol errors (last command was \"%s\")",
1684 host_and_ident(FALSE), smtp_cmd_buffer);
1689 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1690 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1692 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1701 /*************************************************
1702 * Log incomplete transactions *
1703 *************************************************/
1705 /* This function is called after a transaction has been aborted by RSET, QUIT,
1706 connection drops or other errors. It logs the envelope information received
1707 so far in order to preserve address verification attempts.
1709 Argument: string to indicate what aborted the transaction
1714 incomplete_transaction_log(uschar *what)
1716 if (sender_address == NULL || /* No transaction in progress */
1717 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1720 /* Build list of recipients for logging */
1722 if (recipients_count > 0)
1725 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1726 for (i = 0; i < recipients_count; i++)
1727 raw_recipients[i] = recipients_list[i].address;
1728 raw_recipients_count = recipients_count;
1731 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1732 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1738 /*************************************************
1739 * Send SMTP response, possibly multiline *
1740 *************************************************/
1742 /* There are, it seems, broken clients out there that cannot handle multiline
1743 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1744 output nothing for non-final calls, and only the first line for anything else.
1748 final FALSE if the last line isn't the final line
1749 msg message text, possibly containing newlines
1755 smtp_respond(int code, BOOL final, uschar *msg)
1757 if (!final && no_multiline_responses) return;
1761 uschar *nl = Ustrchr(msg, '\n');
1764 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1767 else if (nl[1] == 0 || no_multiline_responses)
1769 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1774 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1776 while (isspace(*msg)) msg++;
1784 /*************************************************
1785 * Handle an ACL failure *
1786 *************************************************/
1788 /* This function is called when acl_check() fails. As well as calls from within
1789 this module, it is called from receive.c for an ACL after DATA. It sorts out
1790 logging the incident, and sets up the error response. A message containing
1791 newlines is turned into a multiline SMTP response, but for logging, only the
1794 There's a table of the response codes to use in globals.c, along with the table
1795 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1796 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1797 that the response should be 252 in the disabled state, because there are broken
1798 clients that try VRFY before RCPT. A 5xx response should be given only when the
1799 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1800 given on refusal, and for AUTH, 503.
1803 where where the ACL was called from
1805 user_msg a message that can be included in an SMTP response
1806 log_msg a message for logging
1808 Returns: 0 in most cases
1809 2 if the failure code was FAIL_DROP, in which case the
1810 SMTP connection should be dropped (this value fits with the
1811 "done" variable in smtp_setup_msg() below)
1815 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1817 int code = acl_wherecodes[where];
1818 BOOL drop = rc == FAIL_DROP;
1820 uschar *sender_info = US"";
1822 #ifdef WITH_CONTENT_SCAN
1823 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1825 (where == ACL_WHERE_PREDATA)? US"DATA" :
1826 (where == ACL_WHERE_DATA)? US"after DATA" :
1827 (smtp_cmd_argument == NULL)?
1828 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
1829 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_argument);
1831 if (drop) rc = FAIL;
1833 /* We used to have sender_address here; however, there was a bug that was not
1834 updating sender_address after a rewrite during a verify. When this bug was
1835 fixed, sender_address at this point became the rewritten address. I'm not sure
1836 this is what should be logged, so I've changed to logging the unrewritten
1837 address to retain backward compatibility. */
1839 #ifndef WITH_CONTENT_SCAN
1840 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1842 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1845 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1846 sender_address_unrewritten : sender_address);
1849 /* If there's been a sender verification failure with a specific message, and
1850 we have not sent a response about it yet, do so now, as a preliminary line for
1851 failures, but not defers. However, log it in both cases. */
1853 if (sender_verified_failed != NULL &&
1854 !testflag(sender_verified_failed, af_sverify_told))
1856 setflag(sender_verified_failed, af_sverify_told);
1858 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1859 host_and_ident(TRUE),
1860 ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail",
1861 sender_verified_failed->address,
1862 (sender_verified_failed->message == NULL)? US"" :
1863 string_sprintf(": %s", sender_verified_failed->message));
1865 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1866 smtp_respond(code, FALSE, string_sprintf(
1867 testflag(sender_verified_failed, af_verify_pmfail)?
1868 "Postmaster verification failed while checking <%s>\n%s\n"
1869 "Several RFCs state that you are required to have a postmaster\n"
1870 "mailbox for each mail domain. This host does not accept mail\n"
1871 "from domains whose servers reject the postmaster address."
1873 testflag(sender_verified_failed, af_verify_nsfail)?
1874 "Callback setup failed while verifying <%s>\n%s\n"
1875 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1876 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1877 "RFC requirements, and stops you from receiving standard bounce\n"
1878 "messages. This host does not accept mail from domains whose servers\n"
1881 "Verification failed for <%s>\n%s",
1882 sender_verified_failed->address,
1883 sender_verified_failed->user_message));
1886 /* Sort out text for logging */
1888 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1889 lognl = Ustrchr(log_msg, '\n');
1890 if (lognl != NULL) *lognl = 0;
1892 /* Send permanent failure response to the command, but the code used isn't
1893 always a 5xx one - see comments at the start of this function. If the original
1894 rc was FAIL_DROP we drop the connection and yield 2. */
1896 if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1897 US"Administrative prohibition" : user_msg);
1899 /* Send temporary failure response to the command. Don't give any details,
1900 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1901 verb, and for a header verify when smtp_return_error_details is set.
1903 This conditional logic is all somewhat of a mess because of the odd
1904 interactions between temp_details and return_error_details. One day it should
1905 be re-implemented in a tidier fashion. */
1909 if (acl_temp_details && user_msg != NULL)
1911 if (smtp_return_error_details &&
1912 sender_verified_failed != NULL &&
1913 sender_verified_failed->message != NULL)
1915 smtp_respond(451, FALSE, sender_verified_failed->message);
1917 smtp_respond(451, TRUE, user_msg);
1920 smtp_printf("451 Temporary local problem - please try later\r\n");
1923 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
1924 Otherwise, log why it is closing if required and return 2. */
1926 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1927 host_and_ident(TRUE),
1928 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1930 if (!drop) return 0;
1932 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1933 smtp_get_connection_info());
1940 /*************************************************
1941 * Verify HELO argument *
1942 *************************************************/
1944 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
1945 matched. It is also called from ACL processing if verify = helo is used and
1946 verification was not previously tried (i.e. helo_try_verify_hosts was not
1947 matched). The result of its processing is to set helo_verified and
1948 helo_verify_failed. These variables should both be FALSE for this function to
1951 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
1952 for IPv6 ::ffff: literals.
1955 Returns: TRUE if testing was completed;
1956 FALSE on a temporary failure
1960 smtp_verify_helo(void)
1964 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
1967 if (sender_helo_name == NULL)
1969 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
1972 else if (sender_helo_name[0] == '[')
1974 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
1975 Ustrlen(sender_host_address)) == 0;
1980 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
1981 helo_verified = Ustrncmp(sender_helo_name + 1,
1982 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
1987 { if (helo_verified) debug_printf("matched host address\n"); }
1990 /* Do a reverse lookup if one hasn't already given a positive or negative
1991 response. If that fails, or the name doesn't match, try checking with a forward
1996 if (sender_host_name == NULL && !host_lookup_failed)
1997 yield = host_name_lookup() != DEFER;
1999 /* If a host name is known, check it and all its aliases. */
2001 if (sender_host_name != NULL)
2003 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2007 HDEBUG(D_receive) debug_printf("matched host name\n");
2011 uschar **aliases = sender_host_aliases;
2012 while (*aliases != NULL)
2014 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2015 if (helo_verified) break;
2020 debug_printf("matched alias %s\n", *(--aliases));
2025 /* Final attempt: try a forward lookup of the helo name */
2031 h.name = sender_helo_name;
2035 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2037 rc = host_find_byname(&h, NULL, NULL, TRUE);
2038 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2043 if (Ustrcmp(hh->address, sender_host_address) == 0)
2045 helo_verified = TRUE;
2047 debug_printf("IP address for %s matches calling address\n",
2057 if (!helo_verified) helo_verify_failed = FALSE; /* We've tried ... */
2064 /*************************************************
2065 * Initialize for SMTP incoming message *
2066 *************************************************/
2068 /* This function conducts the initial dialogue at the start of an incoming SMTP
2069 message, and builds a list of recipients. However, if the incoming message
2070 is part of a batch (-bS option) a separate function is called since it would
2071 be messy having tests splattered about all over this function. This function
2072 therefore handles the case where interaction is occurring. The input and output
2073 files are set up in smtp_in and smtp_out.
2075 The global recipients_list is set to point to a vector of recipient_item
2076 blocks, whose number is given by recipients_count. This is extended by the
2077 receive_add_recipient() function. The global variable sender_address is set to
2078 the sender's address. The yield is +1 if a message has been successfully
2079 started, 0 if a QUIT command was encountered or the connection was refused from
2080 the particular host, or -1 if the connection was lost.
2084 Returns: > 0 message successfully started (reached DATA)
2085 = 0 QUIT read or end of file reached or call refused
2090 smtp_setup_msg(void)
2093 BOOL toomany = FALSE;
2094 BOOL discarded = FALSE;
2095 BOOL last_was_rej_mail = FALSE;
2096 BOOL last_was_rcpt = FALSE;
2097 void *reset_point = store_get(0);
2099 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2101 /* Reset for start of new message. We allow one RSET not to be counted as a
2102 nonmail command, for those MTAs that insist on sending it between every
2103 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2104 TLS between messages (an Exim client may do this if it has messages queued up
2105 for the host). Note: we do NOT reset AUTH at this point. */
2107 smtp_reset(reset_point);
2108 message_ended = END_NOTSTARTED;
2110 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2111 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2112 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2114 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2117 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2119 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2121 /* Batched SMTP is handled in a different function. */
2123 if (smtp_batched_input) return smtp_setup_batch_msg();
2125 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2126 value. The values are 2 larger than the required yield of the function. */
2131 uschar *etrn_command;
2132 uschar *etrn_serialize_key;
2134 uschar *user_msg, *log_msg;
2135 uschar *recipient = NULL;
2136 uschar *hello = NULL;
2137 uschar *set_id = NULL;
2139 BOOL was_rej_mail = FALSE;
2140 BOOL was_rcpt = FALSE;
2141 void (*oldsignal)(int);
2143 int start, end, sender_domain, recipient_domain;
2148 switch(smtp_read_command(TRUE))
2150 /* The AUTH command is not permitted to occur inside a transaction, and may
2151 occur successfully only once per connection, and then only when we've
2152 advertised it. Actually, that isn't quite true. When TLS is started, all
2153 previous information about a connection must be discarded, so a new AUTH is
2154 permitted at that time.
2156 AUTH is initially labelled as a "nonmail command" so that one occurrence
2157 doesn't get counted. We change the label here so that multiple failing
2158 AUTHS will eventually hit the nonmail threshold. */
2161 authentication_failed = TRUE;
2162 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2164 if (!auth_advertised)
2166 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2167 US"AUTH command used when not advertised");
2170 if (sender_host_authenticated != NULL)
2172 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2173 US"already authenticated");
2176 if (sender_address != NULL)
2178 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2179 US"not permitted in mail transaction");
2185 if (acl_smtp_auth != NULL)
2187 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2190 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2195 /* Find the name of the requested authentication mechanism. */
2197 s = smtp_cmd_argument;
2198 while ((c = *smtp_cmd_argument) != 0 && !isspace(c))
2200 if (!isalnum(c) && c != '-' && c != '_')
2202 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2203 US"invalid character in authentication mechanism name");
2206 smtp_cmd_argument++;
2209 /* If not at the end of the line, we must be at white space. Terminate the
2210 name and move the pointer on to any data that may be present. */
2212 if (*smtp_cmd_argument != 0)
2214 *smtp_cmd_argument++ = 0;
2215 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
2218 /* Search for an authentication mechanism which is configured for use
2219 as a server and which has been advertised. */
2221 for (au = auths; au != NULL; au = au->next)
2223 if (strcmpic(s, au->public_name) == 0 && au->server &&
2224 au->advertised) break;
2229 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2230 string_sprintf("%s authentication mechanism not supported", s));
2234 /* Run the checking code, passing the remainder of the command
2235 line as data. Initialize $0 empty. The authenticator may set up
2236 other numeric variables. Afterwards, have a go at expanding the set_id
2237 string, even if authentication failed - for bad passwords it can be useful
2238 to log the userid. On success, require set_id to expand and exist, and
2239 put it in authenticated_id. Save this in permanent store, as the working
2240 store gets reset at HELO, RSET, etc. */
2243 expand_nlength[0] = 0; /* $0 contains nothing */
2245 c = (au->info->servercode)(au, smtp_cmd_argument);
2246 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2247 expand_nmax = -1; /* Reset numeric variables */
2249 /* The value of authenticated_id is stored in the spool file and printed in
2250 log lines. It must not contain binary zeros or newline characters. In
2251 normal use, it never will, but when playing around or testing, this error
2252 can (did) happen. To guard against this, ensure that the id contains only
2253 printing characters. */
2255 if (set_id != NULL) set_id = string_printing(set_id);
2257 /* For the non-OK cases, set up additional logging data if set_id
2262 if (set_id != NULL && *set_id != 0)
2263 set_id = string_sprintf(" (set_id=%s)", set_id);
2267 /* Switch on the result */
2272 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2274 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2275 sender_host_authenticated = au->name;
2276 authentication_failed = FALSE;
2278 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2279 ((sender_host_address != NULL)? pnlocal : 0);
2280 s = ss = US"235 Authentication succeeded";
2281 authenticated_by = au;
2285 /* Authentication succeeded, but we failed to expand the set_id string.
2286 Treat this as a temporary error. */
2288 auth_defer_msg = expand_string_message;
2292 s = string_sprintf("435 Unable to authenticate at present%s",
2293 auth_defer_user_msg);
2294 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2295 set_id, auth_defer_msg);
2299 s = ss = US"501 Invalid base64 data";
2303 s = ss = US"501 Authentication cancelled";
2307 s = ss = US"553 Initial data not expected";
2311 s = US"535 Incorrect authentication data";
2312 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2316 s = US"435 Internal error";
2317 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2318 "check", set_id, c);
2322 smtp_printf("%s\r\n", s);
2324 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2325 au->name, host_and_ident(FALSE), ss);
2327 break; /* AUTH_CMD */
2329 /* The HELO/EHLO commands are permitted to appear in the middle of a
2330 session as well as at the beginning. They have the effect of a reset in
2331 addition to their other functions. Their absence at the start cannot be
2332 taken to be an error.
2336 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2337 or 502 failure replies MUST be returned as appropriate. The SMTP
2338 server MUST stay in the same state after transmitting these replies
2339 that it was in before the EHLO was received.
2341 Therefore, we do not do the reset until after checking the command for
2342 acceptability. This change was made for Exim release 4.11. Previously
2343 it did the reset first. */
2354 HELO_EHLO: /* Common code for HELO and EHLO */
2355 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2356 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2358 /* Reject the HELO if its argument was invalid or non-existent. A
2359 successful check causes the argument to be saved in malloc store. */
2361 if (!check_helo(smtp_cmd_argument))
2363 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2365 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2366 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2367 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2368 string_printing(smtp_cmd_argument));
2370 if (++synprot_error_count > smtp_max_synprot_errors)
2372 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2373 "syntax or protocol errors (last command was \"%s\")",
2374 host_and_ident(FALSE), smtp_cmd_buffer);
2381 /* If sender_host_unknown is true, we have got here via the -bs interface,
2382 not called from inetd. Otherwise, we are running an IP connection and the
2383 host address will be set. If the helo name is the primary name of this
2384 host and we haven't done a reverse lookup, force one now. If helo_required
2385 is set, ensure that the HELO name matches the actual host. If helo_verify
2386 is set, do the same check, but softly. */
2388 if (!sender_host_unknown)
2390 BOOL old_helo_verified = helo_verified;
2391 uschar *p = smtp_cmd_argument;
2393 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2396 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2397 because otherwise the log can be confusing. */
2399 if (sender_host_name == NULL &&
2400 (deliver_domain = sender_helo_name, /* set $domain */
2401 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2402 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2403 (void)host_name_lookup();
2405 /* Rebuild the fullhost info to include the HELO name (and the real name
2406 if it was looked up.) */
2408 host_build_sender_fullhost(); /* Rebuild */
2409 set_process_info("handling%s incoming connection from %s",
2410 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2412 /* Verify if configured. This doesn't give much security, but it does
2413 make some people happy to be able to do it. If helo_required is set,
2414 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2415 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2416 now obsolescent, since the verification can now be requested selectively
2419 helo_verified = helo_verify_failed = FALSE;
2420 if (helo_required || helo_verify)
2422 BOOL tempfail = !smtp_verify_helo();
2427 smtp_printf("%d %s argument does not match calling host\r\n",
2428 tempfail? 451 : 550, hello);
2429 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2430 tempfail? "temporarily " : "",
2431 hello, sender_helo_name, host_and_ident(FALSE));
2432 helo_verified = old_helo_verified;
2433 break; /* End of HELO/EHLO processing */
2435 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2436 "helo_try_verify_hosts\n", hello);
2441 #ifdef EXPERIMENTAL_SPF
2442 /* set up SPF context */
2443 spf_init(sender_helo_name, sender_host_address);
2446 /* Apply an ACL check if one is defined */
2448 if (acl_smtp_helo != NULL)
2450 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2453 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2454 sender_helo_name = NULL;
2455 host_build_sender_fullhost(); /* Rebuild */
2460 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2461 abandoning any previous message. */
2463 received_protocol = (esmtp?
2465 ((sender_host_authenticated != NULL)? pauthed : 0) +
2466 ((tls_active >= 0)? pcrpted : 0)]
2468 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2470 ((sender_host_address != NULL)? pnlocal : 0);
2472 smtp_reset(reset_point);
2475 /* Generate an OK reply, including the ident if present, and also
2476 the IP address if present. Reflecting back the ident is intended
2477 as a deterrent to mail forgers. For maximum efficiency, and also
2478 because some broken systems expect each response to be in a single
2479 packet, arrange that it is sent in one write(). */
2481 auth_advertised = FALSE;
2482 pipelining_advertised = FALSE;
2484 tls_advertised = FALSE;
2487 s = string_sprintf("250 %s Hello %s%s%s",
2488 smtp_active_hostname,
2489 (sender_ident == NULL)? US"" : sender_ident,
2490 (sender_ident == NULL)? US"" : US" at ",
2491 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2496 if (sender_host_address != NULL)
2498 s = string_cat(s, &size, &ptr, US" [", 2);
2499 s = string_cat(s, &size, &ptr, sender_host_address,
2500 Ustrlen(sender_host_address));
2501 s = string_cat(s, &size, &ptr, US"]", 1);
2504 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2506 /* If we received EHLO, we must create a multiline response which includes
2507 the functions supported. */
2513 /* I'm not entirely happy with this, as an MTA is supposed to check
2514 that it has enough room to accept a message of maximum size before
2515 it sends this. However, there seems little point in not sending it.
2516 The actual size check happens later at MAIL FROM time. By postponing it
2517 till then, VRFY and EXPN can be used after EHLO when space is short. */
2519 if (thismessage_size_limit > 0)
2521 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2522 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2526 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2529 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2530 clean; if it has an 8-bit character in its hand, it just sends it. It
2531 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2532 However, some users want this option simply in order to stop MUAs
2533 mangling messages that contain top-bit-set characters. It is therefore
2534 provided as an option. */
2536 if (accept_8bitmime)
2537 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2539 /* Advertise ETRN if there's an ACL checking whether a host is
2540 permitted to issue it; a check is made when any host actually tries. */
2542 if (acl_smtp_etrn != NULL)
2544 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2547 /* Advertise EXPN if there's an ACL checking whether a host is
2548 permitted to issue it; a check is made when any host actually tries. */
2550 if (acl_smtp_expn != NULL)
2552 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2555 /* Exim is quite happy with pipelining, so let the other end know that
2556 it is safe to use it, unless advertising is disabled. */
2558 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2560 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2561 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2562 pipelining_advertised = TRUE;
2565 /* If any server authentication mechanisms are configured, advertise
2566 them if the current host is in auth_advertise_hosts. The problem with
2567 advertising always is that some clients then require users to
2568 authenticate (and aren't configurable otherwise) even though it may not
2569 be necessary (e.g. if the host is in host_accept_relay).
2571 RFC 2222 states that SASL mechanism names contain only upper case
2572 letters, so output the names in upper case, though we actually recognize
2573 them in either case in the AUTH command. */
2577 if (verify_check_host(&auth_advertise_hosts) == OK)
2581 for (au = auths; au != NULL; au = au->next)
2583 if (au->server && (au->advertise_condition == NULL ||
2584 expand_check_condition(au->advertise_condition, au->name,
2585 US"authenticator")))
2590 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2592 auth_advertised = TRUE;
2595 s = string_cat(s, &size, &ptr, US" ", 1);
2596 s = string_cat(s, &size, &ptr, au->public_name,
2597 Ustrlen(au->public_name));
2598 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2599 au->advertised = TRUE;
2601 else au->advertised = FALSE;
2603 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2607 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2608 if it has been included in the binary, and the host matches
2609 tls_advertise_hosts. We must *not* advertise if we are already in a
2610 secure connection. */
2613 if (tls_active < 0 &&
2614 verify_check_host(&tls_advertise_hosts) != FAIL)
2616 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2617 tls_advertised = TRUE;
2621 /* Finish off the multiline reply with one that is always available. */
2623 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2626 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2632 if (tls_active >= 0) (void)tls_write(s, ptr); else
2635 (void)fwrite(s, 1, ptr, smtp_out);
2636 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2638 break; /* HELO/EHLO */
2641 /* The MAIL command requires an address as an operand. All we do
2642 here is to parse it for syntactic correctness. The form "<>" is
2643 a special case which converts into an empty string. The start/end
2644 pointers in the original are not used further for this address, as
2645 it is the canonical extracted address which is all that is kept. */
2648 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2649 was_rej_mail = TRUE; /* Reset if accepted */
2651 if (helo_required && !helo_seen)
2653 smtp_printf("503 HELO or EHLO required\r\n");
2654 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2655 "HELO/EHLO given", host_and_ident(FALSE));
2659 if (sender_address != NULL)
2661 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2662 US"sender already given");
2666 if (smtp_cmd_argument[0] == 0)
2668 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2669 US"MAIL must have an address operand");
2673 /* Check to see if the limit for messages per connection would be
2674 exceeded by accepting further messages. */
2676 if (smtp_accept_max_per_connection > 0 &&
2677 smtp_mailcmd_count > smtp_accept_max_per_connection)
2679 smtp_printf("421 too many messages in this connection\r\n");
2680 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2681 "messages in one connection", host_and_ident(TRUE));
2685 /* Reset for start of message - even if this is going to fail, we
2686 obviously need to throw away any previous data. */
2688 smtp_reset(reset_point);
2690 sender_data = recipient_data = NULL;
2692 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2696 uschar *name, *value, *end;
2697 unsigned long int size;
2699 if (!extract_option(&name, &value)) break;
2701 /* Handle SIZE= by reading the value. We don't do the check till later,
2702 in order to be able to log the sender address on failure. */
2704 if (strcmpic(name, US"SIZE") == 0 &&
2705 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2707 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2709 message_size = (int)size;
2712 /* If this session was initiated with EHLO and accept_8bitmime is set,
2713 Exim will have indicated that it supports the BODY=8BITMIME option. In
2714 fact, it does not support this according to the RFCs, in that it does not
2715 take any special action for forwarding messages containing 8-bit
2716 characters. That is why accept_8bitmime is not the default setting, but
2717 some sites want the action that is provided. We recognize both "8BITMIME"
2718 and "7BIT" as body types, but take no action. */
2720 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2721 (strcmpic(value, US"8BITMIME") == 0 ||
2722 strcmpic(value, US"7BIT") == 0)) {}
2724 /* Handle the AUTH extension. If the value given is not "<>" and either
2725 the ACL says "yes" or there is no ACL but the sending host is
2726 authenticated, we set it up as the authenticated sender. However, if the
2727 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2728 the condition is met. The value of AUTH is an xtext, which means that +,
2729 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2732 else if (strcmpic(name, US"AUTH") == 0)
2734 if (Ustrcmp(value, "<>") != 0)
2739 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2741 /* Put back terminator overrides for error message */
2744 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2745 US"invalid data for AUTH");
2749 if (acl_smtp_mailauth == NULL)
2751 ignore_msg = US"client not authenticated";
2752 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2756 ignore_msg = US"rejected by ACL";
2757 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2758 &user_msg, &log_msg);
2764 if (authenticated_by == NULL ||
2765 authenticated_by->mail_auth_condition == NULL ||
2766 expand_check_condition(authenticated_by->mail_auth_condition,
2767 authenticated_by->name, US"authenticator"))
2768 break; /* Accept the AUTH */
2770 ignore_msg = US"server_mail_auth_condition failed";
2771 if (authenticated_id != NULL)
2772 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2773 ignore_msg, authenticated_id);
2778 authenticated_sender = NULL;
2779 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2780 value, host_and_ident(TRUE), ignore_msg);
2783 /* Should only get DEFER or ERROR here. Put back terminator
2784 overrides for error message */
2789 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2796 /* Unknown option. Stick back the terminator characters and break
2797 the loop. An error for a malformed address will occur. */
2807 /* If we have passed the threshold for rate limiting, apply the current
2808 delay, and update it for next time, provided this is a limited host. */
2810 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2811 verify_check_host(&smtp_ratelimit_hosts) == OK)
2813 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2814 smtp_delay_mail/1000.0);
2815 millisleep((int)smtp_delay_mail);
2816 smtp_delay_mail *= smtp_rlm_factor;
2817 if (smtp_delay_mail > (double)smtp_rlm_limit)
2818 smtp_delay_mail = (double)smtp_rlm_limit;
2821 /* Now extract the address, first applying any SMTP-time rewriting. The
2822 TRUE flag allows "<>" as a sender address. */
2824 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2825 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
2826 global_rewrite_rules) : smtp_cmd_argument;
2828 /* rfc821_domains = TRUE; << no longer needed */
2830 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2832 /* rfc821_domains = FALSE; << no longer needed */
2834 if (raw_sender == NULL)
2836 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
2840 sender_address = raw_sender;
2842 /* If there is a configured size limit for mail, check that this message
2843 doesn't exceed it. The check is postponed to this point so that the sender
2846 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2848 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2849 log_write(L_size_reject,
2850 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2851 "message too big: size%s=%d max=%d",
2853 host_and_ident(TRUE),
2854 (message_size == INT_MAX)? ">" : "",
2856 thismessage_size_limit);
2857 sender_address = NULL;
2861 /* Check there is enough space on the disk unless configured not to.
2862 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2863 plus the current message - i.e. we accept the message only if it won't
2864 reduce the space below the threshold. Add 5000 to the size to allow for
2865 overheads such as the Received: line and storing of recipients, etc.
2866 By putting the check here, even when SIZE is not given, it allow VRFY
2867 and EXPN etc. to be used when space is short. */
2869 if (!receive_check_fs(
2870 (smtp_check_spool_space && message_size >= 0)?
2871 message_size + 5000 : 0))
2873 smtp_printf("452 Space shortage, please try later\r\n");
2874 sender_address = NULL;
2878 /* If sender_address is unqualified, reject it, unless this is a locally
2879 generated message, or the sending host or net is permitted to send
2880 unqualified addresses - typically local machines behaving as MUAs -
2881 in which case just qualify the address. The flag is set above at the start
2882 of the SMTP connection. */
2884 if (sender_domain == 0 && sender_address[0] != 0)
2886 if (allow_unqualified_sender)
2888 sender_domain = Ustrlen(sender_address) + 1;
2889 sender_address = rewrite_address_qualify(sender_address, FALSE);
2890 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2895 smtp_printf("501 %s: sender address must contain a domain\r\n",
2897 log_write(L_smtp_syntax_error,
2898 LOG_MAIN|LOG_REJECT,
2899 "unqualified sender rejected: <%s> %s%s",
2901 host_and_ident(TRUE),
2903 sender_address = NULL;
2908 /* Apply an ACL check if one is defined, before responding */
2910 rc = (acl_smtp_mail == NULL)? OK :
2911 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2913 if (rc == OK || rc == DISCARD)
2915 smtp_printf("250 OK\r\n");
2916 smtp_delay_rcpt = smtp_rlr_base;
2917 recipients_discarded = (rc == DISCARD);
2918 was_rej_mail = FALSE;
2923 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2924 sender_address = NULL;
2929 /* The RCPT command requires an address as an operand. All we do
2930 here is to parse it for syntactic correctness. There may be any number
2931 of RCPT commands, specifying multiple senders. We build them all into
2932 a data structure that is in argc/argv format. The start/end values
2933 given by parse_extract_address are not used, as we keep only the
2934 extracted address. */
2940 /* There must be a sender address; if the sender was rejected and
2941 pipelining was advertised, we assume the client was pipelining, and do not
2942 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2943 get the same treatment. */
2945 if (sender_address == NULL)
2947 if (pipelining_advertised && last_was_rej_mail)
2949 smtp_printf("503 sender not yet given\r\n");
2950 was_rej_mail = TRUE;
2954 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2955 US"sender not yet given");
2956 was_rcpt = FALSE; /* Not a valid RCPT */
2962 /* Check for an operand */
2964 if (smtp_cmd_argument[0] == 0)
2966 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2967 US"RCPT must have an address operand");
2972 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2973 as a recipient address */
2975 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2976 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
2977 global_rewrite_rules) : smtp_cmd_argument;
2979 /* rfc821_domains = TRUE; << no longer needed */
2980 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2981 &recipient_domain, FALSE);
2982 /* rfc821_domains = FALSE; << no longer needed */
2984 if (recipient == NULL)
2986 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
2991 /* If the recipient address is unqualified, reject it, unless this is a
2992 locally generated message. However, unqualified addresses are permitted
2993 from a configured list of hosts and nets - typically when behaving as
2994 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2995 really. The flag is set at the start of the SMTP connection.
2997 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2998 assumed this meant "reserved local part", but the revision of RFC 821 and
2999 friends now makes it absolutely clear that it means *mailbox*. Consequently
3000 we must always qualify this address, regardless. */
3002 if (recipient_domain == 0)
3004 if (allow_unqualified_recipient ||
3005 strcmpic(recipient, US"postmaster") == 0)
3007 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3009 recipient_domain = Ustrlen(recipient) + 1;
3010 recipient = rewrite_address_qualify(recipient, TRUE);
3015 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3017 log_write(L_smtp_syntax_error,
3018 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3019 "<%s> %s%s", recipient, host_and_ident(TRUE),
3025 /* Check maximum allowed */
3027 if (rcpt_count > recipients_max && recipients_max > 0)
3029 if (recipients_max_reject)
3032 smtp_printf("552 too many recipients\r\n");
3034 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3035 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3040 smtp_printf("452 too many recipients\r\n");
3042 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3043 "temporarily rejected: sender=<%s> %s", sender_address,
3044 host_and_ident(TRUE));
3051 /* If we have passed the threshold for rate limiting, apply the current
3052 delay, and update it for next time, provided this is a limited host. */
3054 if (rcpt_count > smtp_rlr_threshold &&
3055 verify_check_host(&smtp_ratelimit_hosts) == OK)
3057 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3058 smtp_delay_rcpt/1000.0);
3059 millisleep((int)smtp_delay_rcpt);
3060 smtp_delay_rcpt *= smtp_rlr_factor;
3061 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3062 smtp_delay_rcpt = (double)smtp_rlr_limit;
3065 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3066 for them. Otherwise, check the access control list for this recipient. */
3068 rc = recipients_discarded? DISCARD :
3069 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3071 /* The ACL was happy */
3075 smtp_printf("250 Accepted\r\n");
3076 receive_add_recipient(recipient, -1);
3079 /* The recipient was discarded */
3081 else if (rc == DISCARD)
3083 smtp_printf("250 Accepted\r\n");
3086 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3087 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3088 (sender_address_unrewritten != NULL)?
3089 sender_address_unrewritten : sender_address,
3090 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3091 (log_msg == NULL)? US"" : US": ",
3092 (log_msg == NULL)? US"" : log_msg);
3095 /* Either the ACL failed the address, or it was deferred. */
3099 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3100 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3105 /* The DATA command is legal only if it follows successful MAIL FROM
3106 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3107 not counted as a protocol error if it follows RCPT (which must have been
3108 rejected if there are no recipients.) This function is complete when a
3109 valid DATA command is encountered.
3111 Note concerning the code used: RFC 2821 says this:
3113 - If there was no MAIL, or no RCPT, command, or all such commands
3114 were rejected, the server MAY return a "command out of sequence"
3115 (503) or "no valid recipients" (554) reply in response to the
3118 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3119 because it is the same whether pipelining is in use or not. */
3122 if (!discarded && recipients_count <= 0)
3124 if (pipelining_advertised && last_was_rcpt)
3125 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3127 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3128 US"valid RCPT command must precede DATA");
3132 if (toomany && recipients_max_reject)
3134 sender_address = NULL; /* This will allow a new MAIL without RSET */
3135 sender_address_unrewritten = NULL;
3136 smtp_printf("554 Too many recipients\r\n");
3140 if (acl_smtp_predata == NULL) rc = OK; else
3142 enable_dollar_recipients = TRUE;
3143 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3145 enable_dollar_recipients = FALSE;
3150 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3152 message_ended = END_NOTENDED; /* Indicate in middle of data */
3155 /* Either the ACL failed the address, or it was deferred. */
3158 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3164 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3166 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3172 /* rfc821_domains = TRUE; << no longer needed */
3173 address = parse_extract_address(smtp_cmd_argument, &errmess, &start, &end,
3174 &recipient_domain, FALSE);
3175 /* rfc821_domains = FALSE; << no longer needed */
3177 if (address == NULL)
3178 s = string_sprintf("501 %s", errmess);
3181 address_item *addr = deliver_make_addr(address, FALSE);
3182 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3183 -1, -1, NULL, NULL, NULL))
3186 s = string_sprintf("250 <%s> is deliverable", address);
3190 s = (addr->message != NULL)?
3191 string_sprintf("451 <%s> %s", address, addr->message) :
3192 string_sprintf("451 Cannot resolve <%s> at this time", address);
3196 s = (addr->message != NULL)?
3197 string_sprintf("550 <%s> %s", address, addr->message) :
3198 string_sprintf("550 <%s> is not deliverable", address);
3199 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3200 smtp_cmd_argument, host_and_ident(TRUE));
3205 smtp_printf("%s\r\n", s);
3211 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3213 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3216 BOOL save_log_testing_mode = log_testing_mode;
3217 address_test_mode = log_testing_mode = TRUE;
3218 (void) verify_address(deliver_make_addr(smtp_cmd_argument, FALSE),
3219 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3221 address_test_mode = FALSE;
3222 log_testing_mode = save_log_testing_mode; /* true for -bh */
3230 if (!tls_advertised)
3232 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3233 US"STARTTLS command used when not advertised");
3237 /* Apply an ACL check if one is defined */
3239 if (acl_smtp_starttls != NULL)
3241 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3245 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3250 /* RFC 2487 is not clear on when this command may be sent, though it
3251 does state that all information previously obtained from the client
3252 must be discarded if a TLS session is started. It seems reasonble to
3253 do an implied RSET when STARTTLS is received. */
3255 incomplete_transaction_log(US"STARTTLS");
3256 smtp_reset(reset_point);
3258 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3260 /* Attempt to start up a TLS session, and if successful, discard all
3261 knowledge that was obtained previously. At least, that's what the RFC says,
3262 and that's what happens by default. However, in order to work round YAEB,
3263 there is an option to remember the esmtp state. Sigh.
3265 We must allow for an extra EHLO command and an extra AUTH command after
3266 STARTTLS that don't add to the nonmail command count. */
3268 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3270 if (!tls_remember_esmtp)
3271 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3272 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3273 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3274 if (sender_helo_name != NULL)
3276 store_free(sender_helo_name);
3277 sender_helo_name = NULL;
3278 host_build_sender_fullhost(); /* Rebuild */
3279 set_process_info("handling incoming TLS connection from %s",
3280 host_and_ident(FALSE));
3282 received_protocol = (esmtp?
3283 protocols[pextend + pcrpted +
3284 ((sender_host_authenticated != NULL)? pauthed : 0)]
3286 protocols[pnormal + pcrpted])
3288 ((sender_host_address != NULL)? pnlocal : 0);
3290 sender_host_authenticated = NULL;
3291 authenticated_id = NULL;
3292 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3293 DEBUG(D_tls) debug_printf("TLS active\n");
3294 break; /* Successful STARTTLS */
3297 /* Some local configuration problem was discovered before actually trying
3298 to do a TLS handshake; give a temporary error. */
3300 else if (rc == DEFER)
3302 smtp_printf("454 TLS currently unavailable\r\n");
3306 /* Hard failure. Reject everything except QUIT or closed connection. One
3307 cause for failure is a nested STARTTLS, in which case tls_active remains
3308 set, but we must still reject all incoming commands. */
3310 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3313 switch(smtp_read_command(FALSE))
3316 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3317 smtp_get_connection_info());
3322 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3323 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3324 smtp_get_connection_info());
3329 smtp_printf("554 Security failure\r\n");
3338 /* The ACL for QUIT is provided for gathering statistical information or
3339 similar; it does not affect the response code, but it can supply a custom
3343 incomplete_transaction_log(US"QUIT");
3345 if (acl_smtp_quit != NULL)
3347 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit,&user_msg,&log_msg);
3349 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3352 else user_msg = NULL;
3354 if (user_msg == NULL)
3355 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3357 smtp_printf("221 %s\r\n", user_msg);
3364 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3365 smtp_get_connection_info());
3370 incomplete_transaction_log(US"RSET");
3371 smtp_reset(reset_point);
3373 smtp_printf("250 Reset OK\r\n");
3374 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3379 smtp_printf("250 OK\r\n");
3383 /* Show ETRN/EXPN/VRFY if there's
3384 an ACL for checking hosts; if actually used, a check will be done for
3388 smtp_printf("214-Commands supported:\r\n");
3392 Ustrcat(buffer, " AUTH");
3394 Ustrcat(buffer, " STARTTLS");
3396 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3397 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3398 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3399 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3400 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3401 smtp_printf("214%s\r\n", buffer);
3407 incomplete_transaction_log(US"connection lost");
3408 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3410 /* Don't log by default unless in the middle of a message, as some mailers
3411 just drop the call rather than sending QUIT, and it clutters up the logs.
3414 if (sender_address != NULL || recipients_count > 0)
3415 log_write(L_lost_incoming_connection,
3417 "unexpected %s while reading SMTP command from %s%s",
3418 sender_host_unknown? "EOF" : "disconnection",
3419 host_and_ident(FALSE), smtp_read_error);
3421 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3422 smtp_get_connection_info(), smtp_read_error);
3429 if (sender_address != NULL)
3431 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3432 US"ETRN is not permitted inside a transaction");
3436 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
3437 host_and_ident(FALSE));
3439 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
3442 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3446 /* Compute the serialization key for this command. */
3448 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_argument);
3450 /* If a command has been specified for running as a result of ETRN, we
3451 permit any argument to ETRN. If not, only the # standard form is permitted,
3452 since that is strictly the only kind of ETRN that can be implemented
3453 according to the RFC. */
3455 if (smtp_etrn_command != NULL)
3459 etrn_command = smtp_etrn_command;
3460 deliver_domain = smtp_cmd_argument;
3461 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3462 US"ETRN processing", &error);
3463 deliver_domain = NULL;
3466 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3468 smtp_printf("458 Internal failure\r\n");
3473 /* Else set up to call Exim with the -R option. */
3477 if (*smtp_cmd_argument++ != '#')
3479 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3480 US"argument must begin with #");
3483 etrn_command = US"exim -R";
3484 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3488 /* If we are host-testing, don't actually do anything. */
3494 debug_printf("ETRN command is: %s\n", etrn_command);
3495 debug_printf("ETRN command execution skipped\n");
3497 smtp_printf("250 OK\r\n");
3502 /* If ETRN queue runs are to be serialized, check the database to
3503 ensure one isn't already running. */
3505 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3507 smtp_printf("458 Already processing %s\r\n", smtp_cmd_argument);
3511 /* Fork a child process and run the command. We don't want to have to
3512 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3513 forking. It should be set that way anyway for external incoming SMTP,
3514 but we save and restore to be tidy. If serialization is required, we
3515 actually run the command in yet another process, so we can wait for it
3516 to complete and then remove the serialization lock. */
3518 oldsignal = signal(SIGCHLD, SIG_IGN);
3520 if ((pid = fork()) == 0)
3522 smtp_input = FALSE; /* This process is not associated with the */
3523 (void)fclose(smtp_in); /* SMTP call any more. */
3524 (void)fclose(smtp_out);
3526 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3528 /* If not serializing, do the exec right away. Otherwise, fork down
3529 into another process. */
3531 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3533 DEBUG(D_exec) debug_print_argv(argv);
3534 exim_nullstd(); /* Ensure std{in,out,err} exist */
3535 execv(CS argv[0], (char *const *)argv);
3536 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3537 etrn_command, strerror(errno));
3538 _exit(EXIT_FAILURE); /* paranoia */
3541 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3542 is, we are in the first subprocess, after forking again. All we can do
3543 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3544 complete, before removing the serialization. */
3547 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3548 "failed: %s", strerror(errno));
3552 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3554 (void)wait(&status);
3555 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3559 enq_end(etrn_serialize_key);
3560 _exit(EXIT_SUCCESS);
3563 /* Back in the top level SMTP process. Check that we started a subprocess
3564 and restore the signal state. */
3568 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3570 smtp_printf("458 Unable to fork process\r\n");
3571 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3573 else smtp_printf("250 OK\r\n");
3575 signal(SIGCHLD, oldsignal);
3580 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3581 US"unexpected argument data");
3585 /* This currently happens only for NULLs, but could be extended. */
3588 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3589 US"NULL character(s) present (shown as '?')");
3590 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3595 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3596 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3597 c = smtp_inend - smtp_inptr;
3598 if (c > 150) c = 150;
3600 incomplete_transaction_log(US"sync failure");
3601 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
3602 "(next input sent too soon: pipelining was%s advertised): "
3603 "rejected \"%s\" %s next input=\"%s\"",
3604 pipelining_advertised? "" : " not",
3605 smtp_cmd_buffer, host_and_ident(TRUE),
3606 string_printing(smtp_inptr));
3607 smtp_printf("554 SMTP synchronization error\r\n");
3608 done = 1; /* Pretend eof - drops connection */
3612 case TOO_MANY_NONMAIL_CMD:
3613 incomplete_transaction_log(US"too many non-mail commands");
3614 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3615 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
3616 smtp_cmd_argument - smtp_cmd_buffer, smtp_cmd_buffer);
3617 smtp_printf("554 Too many nonmail commands\r\n");
3618 done = 1; /* Pretend eof - drops connection */
3623 if (unknown_command_count++ >= smtp_max_unknown_commands)
3625 log_write(L_smtp_syntax_error, LOG_MAIN,
3626 "SMTP syntax error in \"%s\" %s %s",
3627 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
3628 US"unrecognized command");
3629 incomplete_transaction_log(US"unrecognized command");
3630 smtp_printf("500 Too many unrecognized commands\r\n");
3632 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3633 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3637 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3638 US"unrecognized command");
3642 /* This label is used by goto's inside loops that want to break out to
3643 the end of the command-processing loop. */
3646 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3647 last_was_rcpt = was_rcpt; /* protocol error handling */
3651 return done - 2; /* Convert yield values */
3654 /* End of smtp_in.c */