1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.32 2006/02/13 16:23:57 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2006 */
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.
629 If sender_fullhost is NULL, we are at a very early stage of the connection;
630 just use the IP address.
633 Returns: a string describing the connection
637 smtp_get_connection_info(void)
639 uschar *hostname = (sender_fullhost == NULL)?
640 sender_host_address : sender_fullhost;
643 return string_sprintf("SMTP connection from %s", hostname);
645 if (sender_host_unknown || sender_host_notsocket)
646 return string_sprintf("SMTP connection from %s", sender_ident);
649 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
651 if ((log_extra_selector & LX_incoming_interface) != 0 &&
652 interface_address != NULL)
653 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
654 interface_address, interface_port);
656 return string_sprintf("SMTP connection from %s", hostname);
661 /*************************************************
662 * Check HELO line and set sender_helo_name *
663 *************************************************/
665 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
666 the domain name of the sending host, or an ip literal in square brackets. The
667 arrgument is placed in sender_helo_name, which is in malloc store, because it
668 must persist over multiple incoming messages. If helo_accept_junk is set, this
669 host is permitted to send any old junk (needed for some broken hosts).
670 Otherwise, helo_allow_chars can be used for rogue characters in general
671 (typically people want to let in underscores).
674 s the data portion of the line (already past any white space)
676 Returns: TRUE or FALSE
680 check_helo(uschar *s)
683 uschar *end = s + Ustrlen(s);
684 BOOL yield = helo_accept_junk;
686 /* Discard any previous helo name */
688 if (sender_helo_name != NULL)
690 store_free(sender_helo_name);
691 sender_helo_name = NULL;
694 /* Skip tests if junk is permitted. */
698 /* Allow the new standard form for IPv6 address literals, namely,
699 [IPv6:....], and because someone is bound to use it, allow an equivalent
700 IPv4 form. Allow plain addresses as well. */
707 if (strncmpic(s, US"[IPv6:", 6) == 0)
708 yield = (string_is_ip_address(s+6, NULL) == 6);
709 else if (strncmpic(s, US"[IPv4:", 6) == 0)
710 yield = (string_is_ip_address(s+6, NULL) == 4);
712 yield = (string_is_ip_address(s+1, NULL) != 0);
717 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
718 that have been configured (usually underscore - sigh). */
725 if (!isalnum(*s) && *s != '.' && *s != '-' &&
726 Ustrchr(helo_allow_chars, *s) == NULL)
736 /* Save argument if OK */
738 if (yield) sender_helo_name = string_copy_malloc(start);
746 /*************************************************
747 * Extract SMTP command option *
748 *************************************************/
750 /* This function picks the next option setting off the end of smtp_cmd_argument. It
751 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
752 things that can appear there.
755 name point this at the name
756 value point this at the data string
758 Returns: TRUE if found an option
762 extract_option(uschar **name, uschar **value)
765 uschar *v = smtp_cmd_argument + Ustrlen(smtp_cmd_argument) -1;
766 while (isspace(*v)) v--;
769 while (v > smtp_cmd_argument && *v != '=' && !isspace(*v)) v--;
770 if (*v != '=') return FALSE;
773 while(isalpha(n[-1])) n--;
775 if (n[-1] != ' ') return FALSE;
790 /*************************************************
791 * Reset for new message *
792 *************************************************/
794 /* This function is called whenever the SMTP session is reset from
795 within either of the setup functions.
797 Argument: the stacking pool storage reset point
802 smtp_reset(void *reset_point)
805 store_reset(reset_point);
806 recipients_list = NULL;
807 rcpt_count = rcpt_defer_count = rcpt_fail_count =
808 raw_recipients_count = recipients_count = recipients_list_max = 0;
809 message_linecount = 0;
811 acl_warn_headers = NULL;
812 queue_only_policy = FALSE;
813 deliver_freeze = FALSE; /* Can be set by ACL */
814 freeze_tell = freeze_tell_config; /* Can be set by ACL */
815 fake_response = OK; /* Can be set by ACL */
816 #ifdef WITH_CONTENT_SCAN
817 no_mbox_unspool = FALSE; /* Can be set by ACL */
819 submission_mode = FALSE; /* Can be set by ACL */
820 suppress_local_fixups = FALSE; /* Can be set by ACL */
821 active_local_from_check = local_from_check; /* Can be set by ACL */
822 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
823 sender_address = NULL;
824 submission_name = NULL; /* Can be set by ACL */
825 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
826 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
827 sender_verified_list = NULL; /* No senders verified */
828 memset(sender_address_cache, 0, sizeof(sender_address_cache));
829 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
830 authenticated_sender = NULL;
831 #ifdef EXPERIMENTAL_BRIGHTMAIL
835 #ifdef EXPERIMENTAL_DOMAINKEYS
838 #ifdef EXPERIMENTAL_SPF
839 spf_header_comment = NULL;
842 spf_smtp_comment = NULL;
844 body_linecount = body_zerocount = 0;
846 sender_rate = sender_rate_limit = sender_rate_period = NULL;
847 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
848 /* Note that ratelimiters_conn persists across resets. */
850 /* The message variables follow the connection variables. */
852 for (i = 0; i < ACL_MVARS; i++) acl_var[ACL_CVARS + i] = NULL;
854 /* The message body variables use malloc store. They may be set if this is
855 not the first message in an SMTP session and the previous message caused them
856 to be referenced in an ACL. */
858 if (message_body != NULL)
860 store_free(message_body);
864 if (message_body_end != NULL)
866 store_free(message_body_end);
867 message_body_end = NULL;
870 /* Warning log messages are also saved in malloc store. They are saved to avoid
871 repetition in the same message, but it seems right to repeat them for different
874 while (acl_warn_logged != NULL)
876 string_item *this = acl_warn_logged;
877 acl_warn_logged = acl_warn_logged->next;
886 /*************************************************
887 * Initialize for incoming batched SMTP message *
888 *************************************************/
890 /* This function is called from smtp_setup_msg() in the case when
891 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
892 of messages in one file with SMTP commands between them. All errors must be
893 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
894 relevant. After an error on a sender, or an invalid recipient, the remainder
895 of the message is skipped. The value of received_protocol is already set.
898 Returns: > 0 message successfully started (reached DATA)
899 = 0 QUIT read or end of file reached
904 smtp_setup_batch_msg(void)
907 void *reset_point = store_get(0);
909 /* Save the line count at the start of each transaction - single commands
910 like HELO and RSET count as whole transactions. */
912 bsmtp_transaction_linecount = receive_linecount;
914 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
916 smtp_reset(reset_point); /* Reset for start of message */
918 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
919 value. The values are 2 larger than the required yield of the function. */
924 uschar *recipient = NULL;
925 int start, end, sender_domain, recipient_domain;
927 switch(smtp_read_command(FALSE))
929 /* The HELO/EHLO commands set sender_address_helo if they have
930 valid data; otherwise they are ignored, except that they do
931 a reset of the state. */
936 check_helo(smtp_cmd_argument);
940 smtp_reset(reset_point);
941 bsmtp_transaction_linecount = receive_linecount;
945 /* The MAIL FROM command requires an address as an operand. All we
946 do here is to parse it for syntactic correctness. The form "<>" is
947 a special case which converts into an empty string. The start/end
948 pointers in the original are not used further for this address, as
949 it is the canonical extracted address which is all that is kept. */
952 if (sender_address != NULL)
953 /* The function moan_smtp_batch() does not return. */
954 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
956 if (smtp_cmd_argument[0] == 0)
957 /* The function moan_smtp_batch() does not return. */
958 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
960 /* Reset to start of message */
962 smtp_reset(reset_point);
964 /* Apply SMTP rewrite */
966 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
967 rewrite_one(smtp_cmd_argument, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
968 US"", global_rewrite_rules) : smtp_cmd_argument;
970 /* Extract the address; the TRUE flag allows <> as valid */
973 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
976 if (raw_sender == NULL)
977 /* The function moan_smtp_batch() does not return. */
978 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
980 sender_address = string_copy(raw_sender);
982 /* Qualify unqualified sender addresses if permitted to do so. */
984 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
986 if (allow_unqualified_sender)
988 sender_address = rewrite_address_qualify(sender_address, FALSE);
989 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
990 "and rewritten\n", raw_sender);
992 /* The function moan_smtp_batch() does not return. */
993 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
999 /* The RCPT TO command requires an address as an operand. All we do
1000 here is to parse it for syntactic correctness. There may be any number
1001 of RCPT TO commands, specifying multiple senders. We build them all into
1002 a data structure that is in argc/argv format. The start/end values
1003 given by parse_extract_address are not used, as we keep only the
1004 extracted address. */
1007 if (sender_address == NULL)
1008 /* The function moan_smtp_batch() does not return. */
1009 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1011 if (smtp_cmd_argument[0] == 0)
1012 /* The function moan_smtp_batch() does not return. */
1013 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1015 /* Check maximum number allowed */
1017 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1018 /* The function moan_smtp_batch() does not return. */
1019 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1020 recipients_max_reject? "552": "452");
1022 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1023 recipient address */
1025 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1026 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
1027 global_rewrite_rules) : smtp_cmd_argument;
1029 /* rfc821_domains = TRUE; << no longer needed */
1030 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1031 &recipient_domain, FALSE);
1032 /* rfc821_domains = FALSE; << no longer needed */
1034 if (recipient == NULL)
1035 /* The function moan_smtp_batch() does not return. */
1036 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1038 /* If the recipient address is unqualified, qualify it if permitted. Then
1039 add it to the list of recipients. */
1041 if (recipient_domain == 0)
1043 if (allow_unqualified_recipient)
1045 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1047 recipient = rewrite_address_qualify(recipient, TRUE);
1049 /* The function moan_smtp_batch() does not return. */
1050 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1053 receive_add_recipient(recipient, -1);
1057 /* The DATA command is legal only if it follows successful MAIL FROM
1058 and RCPT TO commands. This function is complete when a valid DATA
1059 command is encountered. */
1062 if (sender_address == NULL || recipients_count <= 0)
1064 /* The function moan_smtp_batch() does not return. */
1065 if (sender_address == NULL)
1066 moan_smtp_batch(smtp_cmd_buffer,
1067 "503 MAIL FROM:<sender> command must precede DATA");
1069 moan_smtp_batch(smtp_cmd_buffer,
1070 "503 RCPT TO:<recipient> must precede DATA");
1074 done = 3; /* DATA successfully achieved */
1075 message_ended = END_NOTENDED; /* Indicate in middle of message */
1080 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1087 bsmtp_transaction_linecount = receive_linecount;
1098 /* The function moan_smtp_batch() does not return. */
1099 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1104 /* The function moan_smtp_batch() does not return. */
1105 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1110 /* The function moan_smtp_batch() does not return. */
1111 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1116 return done - 2; /* Convert yield values */
1122 /*************************************************
1123 * Start an SMTP session *
1124 *************************************************/
1126 /* This function is called at the start of an SMTP session. Thereafter,
1127 smtp_setup_msg() is called to initiate each separate message. This
1128 function does host-specific testing, and outputs the banner line.
1131 Returns: FALSE if the session can not continue; something has
1132 gone wrong, or the connection to the host is blocked
1136 smtp_start_session(void)
1142 /* Default values for certain variables */
1144 helo_seen = esmtp = helo_accept_junk = FALSE;
1145 count_nonmail = TRUE_UNSET;
1146 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1147 smtp_delay_mail = smtp_rlm_base;
1148 auth_advertised = FALSE;
1149 pipelining_advertised = FALSE;
1150 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1152 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1154 sender_host_authenticated = NULL;
1155 authenticated_by = NULL;
1158 tls_cipher = tls_peerdn = NULL;
1159 tls_advertised = FALSE;
1162 /* Reset ACL connection variables */
1164 for (i = 0; i < ACL_CVARS; i++) acl_var[i] = NULL;
1166 /* Allow for trailing 0 in the command buffer. */
1168 smtp_cmd_buffer = (uschar *)malloc(smtp_cmd_buffer_size + 1);
1169 if (smtp_cmd_buffer == NULL)
1170 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1171 "malloc() failed for SMTP command buffer");
1173 /* For batched input, the protocol setting can be overridden from the
1174 command line by a trusted caller. */
1176 if (smtp_batched_input)
1178 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1181 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1182 reset later if any of EHLO/AUTH/STARTTLS are received. */
1186 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1188 /* Set up the buffer for inputting using direct read() calls, and arrange to
1189 call the local functions instead of the standard C ones. */
1191 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1192 if (smtp_inbuffer == NULL)
1193 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1194 receive_getc = smtp_getc;
1195 receive_ungetc = smtp_ungetc;
1196 receive_feof = smtp_feof;
1197 receive_ferror = smtp_ferror;
1198 smtp_inptr = smtp_inend = smtp_inbuffer;
1199 smtp_had_eof = smtp_had_error = 0;
1201 /* Set up the message size limit; this may be host-specific */
1203 thismessage_size_limit = expand_string_integer(message_size_limit);
1204 if (thismessage_size_limit < 0)
1206 if (thismessage_size_limit == -1)
1207 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1208 "%s", expand_string_message);
1210 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1211 "%s", expand_string_message);
1212 smtp_closedown(US"Temporary local problem - please try later");
1216 /* When a message is input locally via the -bs or -bS options, sender_host_
1217 unknown is set unless -oMa was used to force an IP address, in which case it
1218 is checked like a real remote connection. When -bs is used from inetd, this
1219 flag is not set, causing the sending host to be checked. The code that deals
1220 with IP source routing (if configured) is never required for -bs or -bS and
1221 the flag sender_host_notsocket is used to suppress it.
1223 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1224 reserve for certain hosts and/or networks. */
1226 if (!sender_host_unknown)
1229 BOOL reserved_host = FALSE;
1231 /* Look up IP options (source routing info) on the socket if this is not an
1232 -oMa "host", and if any are found, log them and drop the connection.
1234 Linux (and others now, see below) is different to everyone else, so there
1235 has to be some conditional compilation here. Versions of Linux before 2.1.15
1236 used a structure whose name was "options". Somebody finally realized that
1237 this name was silly, and it got changed to "ip_options". I use the
1238 newer name here, but there is a fudge in the script that sets up os.h
1239 to define a macro in older Linux systems.
1241 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1242 glibc 2, which has chosen ip_opts for the structure name. This is now
1243 really a glibc thing rather than a Linux thing, so the condition name
1244 has been changed to reflect this. It is relevant also to GNU/Hurd.
1246 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1247 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1248 a special macro defined in the os.h file.
1250 Some DGUX versions on older hardware appear not to support IP options at
1251 all, so there is now a general macro which can be set to cut out this
1254 How to do this properly in IPv6 is not yet known. */
1256 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1258 #ifdef GLIBC_IP_OPTIONS
1259 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1264 #elif defined DARWIN_IP_OPTIONS
1270 if (!host_checking && !sender_host_notsocket)
1273 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1274 struct ip_options *ipopt = store_get(optlen);
1276 struct ip_opts ipoptblock;
1277 struct ip_opts *ipopt = &ipoptblock;
1278 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1280 struct ipoption ipoptblock;
1281 struct ipoption *ipopt = &ipoptblock;
1282 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1285 /* Occasional genuine failures of getsockopt() have been seen - for
1286 example, "reset by peer". Therefore, just log and give up on this
1287 call, unless the error is ENOPROTOOPT. This error is given by systems
1288 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1289 of writing. So for that error, carry on - we just can't do an IP options
1292 DEBUG(D_receive) debug_printf("checking for IP options\n");
1294 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1297 if (errno != ENOPROTOOPT)
1299 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1300 host_and_ident(FALSE), strerror(errno));
1301 smtp_printf("451 SMTP service not available\r\n");
1306 /* Deal with any IP options that are set. On the systems I have looked at,
1307 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1308 more logging data than will fit in big_buffer. Nevertheless, after somebody
1309 questioned this code, I've added in some paranoid checking. */
1311 else if (optlen > 0)
1313 uschar *p = big_buffer;
1314 uschar *pend = big_buffer + big_buffer_size;
1315 uschar *opt, *adptr;
1317 struct in_addr addr;
1320 uschar *optstart = (uschar *)(ipopt->__data);
1322 uschar *optstart = (uschar *)(ipopt->ip_opts);
1324 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1327 DEBUG(D_receive) debug_printf("IP options exist\n");
1329 Ustrcpy(p, "IP options on incoming call:");
1332 for (opt = optstart; opt != NULL &&
1333 opt < (uschar *)(ipopt) + optlen;)
1347 if (!string_format(p, pend-p, " %s [@%s",
1348 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1350 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1352 inet_ntoa(ipopt->ip_dst)))
1354 inet_ntoa(ipopt->ipopt_dst)))
1362 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1364 while (optcount-- > 0)
1366 memcpy(&addr, adptr, sizeof(addr));
1367 if (!string_format(p, pend - p - 1, "%s%s",
1368 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1374 adptr += sizeof(struct in_addr);
1383 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1386 for (i = 0; i < opt[1]; i++)
1388 sprintf(CS p, "%2.2x ", opt[i]);
1399 log_write(0, LOG_MAIN, "%s", big_buffer);
1401 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1403 log_write(0, LOG_MAIN|LOG_REJECT,
1404 "connection from %s refused (IP options)", host_and_ident(FALSE));
1406 smtp_printf("554 SMTP service not available\r\n");
1410 /* Length of options = 0 => there are no options */
1412 else DEBUG(D_receive) debug_printf("no IP options found\n");
1414 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1416 /* Set keep-alive in socket options. The option is on by default. This
1417 setting is an attempt to get rid of some hanging connections that stick in
1418 read() when the remote end (usually a dialup) goes away. */
1420 if (smtp_accept_keepalive && !sender_host_notsocket)
1421 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1423 /* If the current host matches host_lookup, set the name by doing a
1424 reverse lookup. On failure, sender_host_name will be NULL and
1425 host_lookup_failed will be TRUE. This may or may not be serious - optional
1428 if (verify_check_host(&host_lookup) == OK)
1430 (void)host_name_lookup();
1431 host_build_sender_fullhost();
1434 /* Delay this until we have the full name, if it is looked up. */
1436 set_process_info("handling incoming connection from %s",
1437 host_and_ident(FALSE));
1439 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1440 smtps port for use with older style SSL MTAs. */
1443 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1447 /* Test for explicit connection rejection */
1449 if (verify_check_host(&host_reject_connection) == OK)
1451 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1452 "from %s (host_reject_connection)", host_and_ident(FALSE));
1453 smtp_printf("554 SMTP service not available\r\n");
1457 /* Test with TCP Wrappers if so configured */
1459 #ifdef USE_TCP_WRAPPERS
1460 if (!hosts_ctl("exim",
1461 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1462 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1463 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1465 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1466 log_write(L_connection_reject,
1467 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1468 "(tcp wrappers)", host_and_ident(FALSE));
1469 smtp_printf("554 SMTP service not available\r\n");
1474 /* Check for reserved slots. Note that the count value doesn't include
1475 this process, as it gets upped in the parent process. */
1477 if (smtp_accept_max > 0 &&
1478 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1480 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1482 log_write(L_connection_reject,
1483 LOG_MAIN, "temporarily refused connection from %s: not in "
1484 "reserve list: connected=%d max=%d reserve=%d%s",
1485 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1486 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1487 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1488 "please try again later\r\n", smtp_active_hostname);
1491 reserved_host = TRUE;
1494 /* If a load level above which only messages from reserved hosts are
1495 accepted is set, check the load. For incoming calls via the daemon, the
1496 check is done in the superior process if there are no reserved hosts, to
1497 save a fork. In all cases, the load average will already be available
1498 in a global variable at this point. */
1500 if (smtp_load_reserve >= 0 &&
1501 load_average > smtp_load_reserve &&
1503 verify_check_host(&smtp_reserve_hosts) != OK)
1505 log_write(L_connection_reject,
1506 LOG_MAIN, "temporarily refused connection from %s: not in "
1507 "reserve list and load average = %.2f", host_and_ident(FALSE),
1508 (double)load_average/1000.0);
1509 smtp_printf("421 %s: Too much load; please try again later\r\n",
1510 smtp_active_hostname);
1514 /* Determine whether unqualified senders or recipients are permitted
1515 for this host. Unfortunately, we have to do this every time, in order to
1516 set the flags so that they can be inspected when considering qualifying
1517 addresses in the headers. For a site that permits no qualification, this
1518 won't take long, however. */
1520 allow_unqualified_sender =
1521 verify_check_host(&sender_unqualified_hosts) == OK;
1523 allow_unqualified_recipient =
1524 verify_check_host(&recipient_unqualified_hosts) == OK;
1526 /* Determine whether HELO/EHLO is required for this host. The requirement
1527 can be hard or soft. */
1529 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1531 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1533 /* Determine whether this hosts is permitted to send syntactic junk
1534 after a HELO or EHLO command. */
1536 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1539 /* For batch SMTP input we are now done. */
1541 if (smtp_batched_input) return TRUE;
1543 /* Run the ACL if it exists */
1545 if (acl_smtp_connect != NULL)
1548 uschar *user_msg, *log_msg;
1549 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1553 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1558 /* Output the initial message for a two-way SMTP connection. It may contain
1559 newlines, which then cause a multi-line response to be given. */
1561 s = expand_string(smtp_banner);
1563 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1564 "failed: %s", smtp_banner, expand_string_message);
1566 /* Remove any terminating newlines; might as well remove trailing space too */
1569 while (p > s && isspace(p[-1])) p--;
1572 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1573 is all contained in a single IP packet. The original code wrote out the
1574 greeting using several calls to fprint/fputc, and on busy servers this could
1575 cause it to be split over more than one packet - which caused CC:Mail to fall
1576 over when it got the second part of the greeting after sending its first
1577 command. Sigh. To try to avoid this, build the complete greeting message
1578 first, and output it in one fell swoop. This gives a better chance of it
1579 ending up as a single packet. */
1581 ss = store_get(size);
1585 do /* At least once, in case we have an empty string */
1588 uschar *linebreak = Ustrchr(p, '\n');
1589 if (linebreak == NULL)
1592 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1596 len = linebreak - p;
1597 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1599 ss = string_cat(ss, &size, &ptr, p, len);
1600 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1602 if (linebreak != NULL) p++;
1606 ss[ptr] = 0; /* string_cat leaves room for this */
1608 /* Before we write the banner, check that there is no input pending, unless
1609 this synchronisation check is disabled. */
1611 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1614 struct timeval tzero;
1618 FD_SET(fileno(smtp_in), &fds);
1619 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1622 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1625 if (rc > 150) rc = 150;
1626 smtp_inbuffer[rc] = 0;
1627 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1628 "synchronization error (input sent without waiting for greeting): "
1629 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1630 string_printing(smtp_inbuffer));
1631 smtp_printf("554 SMTP synchronization error\r\n");
1637 /* Now output the banner */
1639 smtp_printf("%s", ss);
1647 /*************************************************
1648 * Handle SMTP syntax and protocol errors *
1649 *************************************************/
1651 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1652 to do so. Then transmit the error response. The return value depends on the
1653 number of syntax and protocol errors in this SMTP session.
1656 type error type, given as a log flag bit
1657 code response code; <= 0 means don't send a response
1658 data data to reflect in the response (can be NULL)
1659 errmess the error message
1661 Returns: -1 limit of syntax/protocol errors NOT exceeded
1662 +1 limit of syntax/protocol errors IS exceeded
1664 These values fit in with the values of the "done" variable in the main
1665 processing loop in smtp_setup_msg(). */
1668 synprot_error(int type, int code, uschar *data, uschar *errmess)
1672 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1673 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1674 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1676 if (++synprot_error_count > smtp_max_synprot_errors)
1679 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1680 "syntax or protocol errors (last command was \"%s\")",
1681 host_and_ident(FALSE), smtp_cmd_buffer);
1686 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1687 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1689 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1698 /*************************************************
1699 * Log incomplete transactions *
1700 *************************************************/
1702 /* This function is called after a transaction has been aborted by RSET, QUIT,
1703 connection drops or other errors. It logs the envelope information received
1704 so far in order to preserve address verification attempts.
1706 Argument: string to indicate what aborted the transaction
1711 incomplete_transaction_log(uschar *what)
1713 if (sender_address == NULL || /* No transaction in progress */
1714 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1717 /* Build list of recipients for logging */
1719 if (recipients_count > 0)
1722 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1723 for (i = 0; i < recipients_count; i++)
1724 raw_recipients[i] = recipients_list[i].address;
1725 raw_recipients_count = recipients_count;
1728 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1729 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1735 /*************************************************
1736 * Send SMTP response, possibly multiline *
1737 *************************************************/
1739 /* There are, it seems, broken clients out there that cannot handle multiline
1740 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1741 output nothing for non-final calls, and only the first line for anything else.
1745 final FALSE if the last line isn't the final line
1746 msg message text, possibly containing newlines
1752 smtp_respond(int code, BOOL final, uschar *msg)
1754 if (!final && no_multiline_responses) return;
1758 uschar *nl = Ustrchr(msg, '\n');
1761 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1764 else if (nl[1] == 0 || no_multiline_responses)
1766 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1771 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1773 while (isspace(*msg)) msg++;
1781 /*************************************************
1782 * Handle an ACL failure *
1783 *************************************************/
1785 /* This function is called when acl_check() fails. As well as calls from within
1786 this module, it is called from receive.c for an ACL after DATA. It sorts out
1787 logging the incident, and sets up the error response. A message containing
1788 newlines is turned into a multiline SMTP response, but for logging, only the
1791 There's a table of the response codes to use in globals.c, along with the table
1792 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1793 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1794 that the response should be 252 in the disabled state, because there are broken
1795 clients that try VRFY before RCPT. A 5xx response should be given only when the
1796 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1797 given on refusal, and for AUTH, 503.
1800 where where the ACL was called from
1802 user_msg a message that can be included in an SMTP response
1803 log_msg a message for logging
1805 Returns: 0 in most cases
1806 2 if the failure code was FAIL_DROP, in which case the
1807 SMTP connection should be dropped (this value fits with the
1808 "done" variable in smtp_setup_msg() below)
1812 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1814 int code = acl_wherecodes[where];
1815 BOOL drop = rc == FAIL_DROP;
1817 uschar *sender_info = US"";
1819 #ifdef WITH_CONTENT_SCAN
1820 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1822 (where == ACL_WHERE_PREDATA)? US"DATA" :
1823 (where == ACL_WHERE_DATA)? US"after DATA" :
1824 (smtp_cmd_argument == NULL)?
1825 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
1826 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_argument);
1828 if (drop) rc = FAIL;
1830 /* We used to have sender_address here; however, there was a bug that was not
1831 updating sender_address after a rewrite during a verify. When this bug was
1832 fixed, sender_address at this point became the rewritten address. I'm not sure
1833 this is what should be logged, so I've changed to logging the unrewritten
1834 address to retain backward compatibility. */
1836 #ifndef WITH_CONTENT_SCAN
1837 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1839 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1842 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1843 sender_address_unrewritten : sender_address);
1846 /* If there's been a sender verification failure with a specific message, and
1847 we have not sent a response about it yet, do so now, as a preliminary line for
1848 failures, but not defers. However, log it in both cases. */
1850 if (sender_verified_failed != NULL &&
1851 !testflag(sender_verified_failed, af_sverify_told))
1853 setflag(sender_verified_failed, af_sverify_told);
1855 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1856 host_and_ident(TRUE),
1857 ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail",
1858 sender_verified_failed->address,
1859 (sender_verified_failed->message == NULL)? US"" :
1860 string_sprintf(": %s", sender_verified_failed->message));
1862 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1863 smtp_respond(code, FALSE, string_sprintf(
1864 testflag(sender_verified_failed, af_verify_pmfail)?
1865 "Postmaster verification failed while checking <%s>\n%s\n"
1866 "Several RFCs state that you are required to have a postmaster\n"
1867 "mailbox for each mail domain. This host does not accept mail\n"
1868 "from domains whose servers reject the postmaster address."
1870 testflag(sender_verified_failed, af_verify_nsfail)?
1871 "Callback setup failed while verifying <%s>\n%s\n"
1872 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1873 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1874 "RFC requirements, and stops you from receiving standard bounce\n"
1875 "messages. This host does not accept mail from domains whose servers\n"
1878 "Verification failed for <%s>\n%s",
1879 sender_verified_failed->address,
1880 sender_verified_failed->user_message));
1883 /* Sort out text for logging */
1885 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1886 lognl = Ustrchr(log_msg, '\n');
1887 if (lognl != NULL) *lognl = 0;
1889 /* Send permanent failure response to the command, but the code used isn't
1890 always a 5xx one - see comments at the start of this function. If the original
1891 rc was FAIL_DROP we drop the connection and yield 2. */
1893 if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1894 US"Administrative prohibition" : user_msg);
1896 /* Send temporary failure response to the command. Don't give any details,
1897 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1898 verb, and for a header verify when smtp_return_error_details is set.
1900 This conditional logic is all somewhat of a mess because of the odd
1901 interactions between temp_details and return_error_details. One day it should
1902 be re-implemented in a tidier fashion. */
1906 if (acl_temp_details && user_msg != NULL)
1908 if (smtp_return_error_details &&
1909 sender_verified_failed != NULL &&
1910 sender_verified_failed->message != NULL)
1912 smtp_respond(451, FALSE, sender_verified_failed->message);
1914 smtp_respond(451, TRUE, user_msg);
1917 smtp_printf("451 Temporary local problem - please try later\r\n");
1920 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
1921 Otherwise, log why it is closing if required and return 2. */
1923 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1924 host_and_ident(TRUE),
1925 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1927 if (!drop) return 0;
1929 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1930 smtp_get_connection_info());
1937 /*************************************************
1938 * Verify HELO argument *
1939 *************************************************/
1941 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
1942 matched. It is also called from ACL processing if verify = helo is used and
1943 verification was not previously tried (i.e. helo_try_verify_hosts was not
1944 matched). The result of its processing is to set helo_verified and
1945 helo_verify_failed. These variables should both be FALSE for this function to
1948 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
1949 for IPv6 ::ffff: literals.
1952 Returns: TRUE if testing was completed;
1953 FALSE on a temporary failure
1957 smtp_verify_helo(void)
1961 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
1964 if (sender_helo_name == NULL)
1966 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
1969 else if (sender_helo_name[0] == '[')
1971 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
1972 Ustrlen(sender_host_address)) == 0;
1977 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
1978 helo_verified = Ustrncmp(sender_helo_name + 1,
1979 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
1984 { if (helo_verified) debug_printf("matched host address\n"); }
1987 /* Do a reverse lookup if one hasn't already given a positive or negative
1988 response. If that fails, or the name doesn't match, try checking with a forward
1993 if (sender_host_name == NULL && !host_lookup_failed)
1994 yield = host_name_lookup() != DEFER;
1996 /* If a host name is known, check it and all its aliases. */
1998 if (sender_host_name != NULL)
2000 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2004 HDEBUG(D_receive) debug_printf("matched host name\n");
2008 uschar **aliases = sender_host_aliases;
2009 while (*aliases != NULL)
2011 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2012 if (helo_verified) break;
2017 debug_printf("matched alias %s\n", *(--aliases));
2022 /* Final attempt: try a forward lookup of the helo name */
2028 h.name = sender_helo_name;
2032 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2034 rc = host_find_byname(&h, NULL, NULL, TRUE);
2035 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2040 if (Ustrcmp(hh->address, sender_host_address) == 0)
2042 helo_verified = TRUE;
2044 debug_printf("IP address for %s matches calling address\n",
2054 if (!helo_verified) helo_verify_failed = FALSE; /* We've tried ... */
2061 /*************************************************
2062 * Initialize for SMTP incoming message *
2063 *************************************************/
2065 /* This function conducts the initial dialogue at the start of an incoming SMTP
2066 message, and builds a list of recipients. However, if the incoming message
2067 is part of a batch (-bS option) a separate function is called since it would
2068 be messy having tests splattered about all over this function. This function
2069 therefore handles the case where interaction is occurring. The input and output
2070 files are set up in smtp_in and smtp_out.
2072 The global recipients_list is set to point to a vector of recipient_item
2073 blocks, whose number is given by recipients_count. This is extended by the
2074 receive_add_recipient() function. The global variable sender_address is set to
2075 the sender's address. The yield is +1 if a message has been successfully
2076 started, 0 if a QUIT command was encountered or the connection was refused from
2077 the particular host, or -1 if the connection was lost.
2081 Returns: > 0 message successfully started (reached DATA)
2082 = 0 QUIT read or end of file reached or call refused
2087 smtp_setup_msg(void)
2090 BOOL toomany = FALSE;
2091 BOOL discarded = FALSE;
2092 BOOL last_was_rej_mail = FALSE;
2093 BOOL last_was_rcpt = FALSE;
2094 void *reset_point = store_get(0);
2096 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2098 /* Reset for start of new message. We allow one RSET not to be counted as a
2099 nonmail command, for those MTAs that insist on sending it between every
2100 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2101 TLS between messages (an Exim client may do this if it has messages queued up
2102 for the host). Note: we do NOT reset AUTH at this point. */
2104 smtp_reset(reset_point);
2105 message_ended = END_NOTSTARTED;
2107 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2108 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2109 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2111 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2114 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2116 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2118 /* Batched SMTP is handled in a different function. */
2120 if (smtp_batched_input) return smtp_setup_batch_msg();
2122 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2123 value. The values are 2 larger than the required yield of the function. */
2128 uschar *etrn_command;
2129 uschar *etrn_serialize_key;
2131 uschar *user_msg, *log_msg;
2132 uschar *recipient = NULL;
2133 uschar *hello = NULL;
2134 uschar *set_id = NULL;
2136 BOOL was_rej_mail = FALSE;
2137 BOOL was_rcpt = FALSE;
2138 void (*oldsignal)(int);
2140 int start, end, sender_domain, recipient_domain;
2145 switch(smtp_read_command(TRUE))
2147 /* The AUTH command is not permitted to occur inside a transaction, and may
2148 occur successfully only once per connection, and then only when we've
2149 advertised it. Actually, that isn't quite true. When TLS is started, all
2150 previous information about a connection must be discarded, so a new AUTH is
2151 permitted at that time.
2153 AUTH is initially labelled as a "nonmail command" so that one occurrence
2154 doesn't get counted. We change the label here so that multiple failing
2155 AUTHS will eventually hit the nonmail threshold. */
2158 authentication_failed = TRUE;
2159 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2161 if (!auth_advertised)
2163 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2164 US"AUTH command used when not advertised");
2167 if (sender_host_authenticated != NULL)
2169 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2170 US"already authenticated");
2173 if (sender_address != NULL)
2175 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2176 US"not permitted in mail transaction");
2182 if (acl_smtp_auth != NULL)
2184 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2187 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2192 /* Find the name of the requested authentication mechanism. */
2194 s = smtp_cmd_argument;
2195 while ((c = *smtp_cmd_argument) != 0 && !isspace(c))
2197 if (!isalnum(c) && c != '-' && c != '_')
2199 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2200 US"invalid character in authentication mechanism name");
2203 smtp_cmd_argument++;
2206 /* If not at the end of the line, we must be at white space. Terminate the
2207 name and move the pointer on to any data that may be present. */
2209 if (*smtp_cmd_argument != 0)
2211 *smtp_cmd_argument++ = 0;
2212 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
2215 /* Search for an authentication mechanism which is configured for use
2216 as a server and which has been advertised. */
2218 for (au = auths; au != NULL; au = au->next)
2220 if (strcmpic(s, au->public_name) == 0 && au->server &&
2221 au->advertised) break;
2226 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2227 string_sprintf("%s authentication mechanism not supported", s));
2231 /* Run the checking code, passing the remainder of the command line as
2232 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2233 it as the only set numerical variable. The authenticator may set $auth<n>
2234 and also set other numeric variables. The $auth<n> variables are preferred
2235 nowadays; the numerical variables remain for backwards compatibility.
2237 Afterwards, have a go at expanding the set_id string, even if
2238 authentication failed - for bad passwords it can be useful to log the
2239 userid. On success, require set_id to expand and exist, and put it in
2240 authenticated_id. Save this in permanent store, as the working store gets
2241 reset at HELO, RSET, etc. */
2243 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2245 expand_nlength[0] = 0; /* $0 contains nothing */
2247 c = (au->info->servercode)(au, smtp_cmd_argument);
2248 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2249 expand_nmax = -1; /* Reset numeric variables */
2250 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2252 /* The value of authenticated_id is stored in the spool file and printed in
2253 log lines. It must not contain binary zeros or newline characters. In
2254 normal use, it never will, but when playing around or testing, this error
2255 can (did) happen. To guard against this, ensure that the id contains only
2256 printing characters. */
2258 if (set_id != NULL) set_id = string_printing(set_id);
2260 /* For the non-OK cases, set up additional logging data if set_id
2265 if (set_id != NULL && *set_id != 0)
2266 set_id = string_sprintf(" (set_id=%s)", set_id);
2270 /* Switch on the result */
2275 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2277 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2278 sender_host_authenticated = au->name;
2279 authentication_failed = FALSE;
2281 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2282 ((sender_host_address != NULL)? pnlocal : 0);
2283 s = ss = US"235 Authentication succeeded";
2284 authenticated_by = au;
2288 /* Authentication succeeded, but we failed to expand the set_id string.
2289 Treat this as a temporary error. */
2291 auth_defer_msg = expand_string_message;
2295 s = string_sprintf("435 Unable to authenticate at present%s",
2296 auth_defer_user_msg);
2297 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2298 set_id, auth_defer_msg);
2302 s = ss = US"501 Invalid base64 data";
2306 s = ss = US"501 Authentication cancelled";
2310 s = ss = US"553 Initial data not expected";
2314 s = US"535 Incorrect authentication data";
2315 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2319 s = US"435 Internal error";
2320 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2321 "check", set_id, c);
2325 smtp_printf("%s\r\n", s);
2327 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2328 au->name, host_and_ident(FALSE), ss);
2330 break; /* AUTH_CMD */
2332 /* The HELO/EHLO commands are permitted to appear in the middle of a
2333 session as well as at the beginning. They have the effect of a reset in
2334 addition to their other functions. Their absence at the start cannot be
2335 taken to be an error.
2339 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2340 or 502 failure replies MUST be returned as appropriate. The SMTP
2341 server MUST stay in the same state after transmitting these replies
2342 that it was in before the EHLO was received.
2344 Therefore, we do not do the reset until after checking the command for
2345 acceptability. This change was made for Exim release 4.11. Previously
2346 it did the reset first. */
2357 HELO_EHLO: /* Common code for HELO and EHLO */
2358 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2359 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2361 /* Reject the HELO if its argument was invalid or non-existent. A
2362 successful check causes the argument to be saved in malloc store. */
2364 if (!check_helo(smtp_cmd_argument))
2366 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2368 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2369 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2370 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2371 string_printing(smtp_cmd_argument));
2373 if (++synprot_error_count > smtp_max_synprot_errors)
2375 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2376 "syntax or protocol errors (last command was \"%s\")",
2377 host_and_ident(FALSE), smtp_cmd_buffer);
2384 /* If sender_host_unknown is true, we have got here via the -bs interface,
2385 not called from inetd. Otherwise, we are running an IP connection and the
2386 host address will be set. If the helo name is the primary name of this
2387 host and we haven't done a reverse lookup, force one now. If helo_required
2388 is set, ensure that the HELO name matches the actual host. If helo_verify
2389 is set, do the same check, but softly. */
2391 if (!sender_host_unknown)
2393 BOOL old_helo_verified = helo_verified;
2394 uschar *p = smtp_cmd_argument;
2396 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2399 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2400 because otherwise the log can be confusing. */
2402 if (sender_host_name == NULL &&
2403 (deliver_domain = sender_helo_name, /* set $domain */
2404 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2405 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2406 (void)host_name_lookup();
2408 /* Rebuild the fullhost info to include the HELO name (and the real name
2409 if it was looked up.) */
2411 host_build_sender_fullhost(); /* Rebuild */
2412 set_process_info("handling%s incoming connection from %s",
2413 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2415 /* Verify if configured. This doesn't give much security, but it does
2416 make some people happy to be able to do it. If helo_required is set,
2417 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2418 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2419 now obsolescent, since the verification can now be requested selectively
2422 helo_verified = helo_verify_failed = FALSE;
2423 if (helo_required || helo_verify)
2425 BOOL tempfail = !smtp_verify_helo();
2430 smtp_printf("%d %s argument does not match calling host\r\n",
2431 tempfail? 451 : 550, hello);
2432 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2433 tempfail? "temporarily " : "",
2434 hello, sender_helo_name, host_and_ident(FALSE));
2435 helo_verified = old_helo_verified;
2436 break; /* End of HELO/EHLO processing */
2438 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2439 "helo_try_verify_hosts\n", hello);
2444 #ifdef EXPERIMENTAL_SPF
2445 /* set up SPF context */
2446 spf_init(sender_helo_name, sender_host_address);
2449 /* Apply an ACL check if one is defined */
2451 if (acl_smtp_helo != NULL)
2453 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2456 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2457 sender_helo_name = NULL;
2458 host_build_sender_fullhost(); /* Rebuild */
2463 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2464 abandoning any previous message. */
2466 received_protocol = (esmtp?
2468 ((sender_host_authenticated != NULL)? pauthed : 0) +
2469 ((tls_active >= 0)? pcrpted : 0)]
2471 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2473 ((sender_host_address != NULL)? pnlocal : 0);
2475 smtp_reset(reset_point);
2478 /* Generate an OK reply, including the ident if present, and also
2479 the IP address if present. Reflecting back the ident is intended
2480 as a deterrent to mail forgers. For maximum efficiency, and also
2481 because some broken systems expect each response to be in a single
2482 packet, arrange that it is sent in one write(). */
2484 auth_advertised = FALSE;
2485 pipelining_advertised = FALSE;
2487 tls_advertised = FALSE;
2490 s = string_sprintf("250 %s Hello %s%s%s",
2491 smtp_active_hostname,
2492 (sender_ident == NULL)? US"" : sender_ident,
2493 (sender_ident == NULL)? US"" : US" at ",
2494 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2499 if (sender_host_address != NULL)
2501 s = string_cat(s, &size, &ptr, US" [", 2);
2502 s = string_cat(s, &size, &ptr, sender_host_address,
2503 Ustrlen(sender_host_address));
2504 s = string_cat(s, &size, &ptr, US"]", 1);
2507 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2509 /* If we received EHLO, we must create a multiline response which includes
2510 the functions supported. */
2516 /* I'm not entirely happy with this, as an MTA is supposed to check
2517 that it has enough room to accept a message of maximum size before
2518 it sends this. However, there seems little point in not sending it.
2519 The actual size check happens later at MAIL FROM time. By postponing it
2520 till then, VRFY and EXPN can be used after EHLO when space is short. */
2522 if (thismessage_size_limit > 0)
2524 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2525 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2529 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2532 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2533 clean; if it has an 8-bit character in its hand, it just sends it. It
2534 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2535 However, some users want this option simply in order to stop MUAs
2536 mangling messages that contain top-bit-set characters. It is therefore
2537 provided as an option. */
2539 if (accept_8bitmime)
2540 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2542 /* Advertise ETRN if there's an ACL checking whether a host is
2543 permitted to issue it; a check is made when any host actually tries. */
2545 if (acl_smtp_etrn != NULL)
2547 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2550 /* Advertise EXPN if there's an ACL checking whether a host is
2551 permitted to issue it; a check is made when any host actually tries. */
2553 if (acl_smtp_expn != NULL)
2555 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2558 /* Exim is quite happy with pipelining, so let the other end know that
2559 it is safe to use it, unless advertising is disabled. */
2561 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2563 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2564 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2565 pipelining_advertised = TRUE;
2568 /* If any server authentication mechanisms are configured, advertise
2569 them if the current host is in auth_advertise_hosts. The problem with
2570 advertising always is that some clients then require users to
2571 authenticate (and aren't configurable otherwise) even though it may not
2572 be necessary (e.g. if the host is in host_accept_relay).
2574 RFC 2222 states that SASL mechanism names contain only upper case
2575 letters, so output the names in upper case, though we actually recognize
2576 them in either case in the AUTH command. */
2580 if (verify_check_host(&auth_advertise_hosts) == OK)
2584 for (au = auths; au != NULL; au = au->next)
2586 if (au->server && (au->advertise_condition == NULL ||
2587 expand_check_condition(au->advertise_condition, au->name,
2588 US"authenticator")))
2593 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2595 auth_advertised = TRUE;
2598 s = string_cat(s, &size, &ptr, US" ", 1);
2599 s = string_cat(s, &size, &ptr, au->public_name,
2600 Ustrlen(au->public_name));
2601 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2602 au->advertised = TRUE;
2604 else au->advertised = FALSE;
2606 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2610 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2611 if it has been included in the binary, and the host matches
2612 tls_advertise_hosts. We must *not* advertise if we are already in a
2613 secure connection. */
2616 if (tls_active < 0 &&
2617 verify_check_host(&tls_advertise_hosts) != FAIL)
2619 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2620 tls_advertised = TRUE;
2624 /* Finish off the multiline reply with one that is always available. */
2626 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2629 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2635 if (tls_active >= 0) (void)tls_write(s, ptr); else
2638 (void)fwrite(s, 1, ptr, smtp_out);
2639 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2641 break; /* HELO/EHLO */
2644 /* The MAIL command requires an address as an operand. All we do
2645 here is to parse it for syntactic correctness. The form "<>" is
2646 a special case which converts into an empty string. The start/end
2647 pointers in the original are not used further for this address, as
2648 it is the canonical extracted address which is all that is kept. */
2651 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2652 was_rej_mail = TRUE; /* Reset if accepted */
2654 if (helo_required && !helo_seen)
2656 smtp_printf("503 HELO or EHLO required\r\n");
2657 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2658 "HELO/EHLO given", host_and_ident(FALSE));
2662 if (sender_address != NULL)
2664 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2665 US"sender already given");
2669 if (smtp_cmd_argument[0] == 0)
2671 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2672 US"MAIL must have an address operand");
2676 /* Check to see if the limit for messages per connection would be
2677 exceeded by accepting further messages. */
2679 if (smtp_accept_max_per_connection > 0 &&
2680 smtp_mailcmd_count > smtp_accept_max_per_connection)
2682 smtp_printf("421 too many messages in this connection\r\n");
2683 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2684 "messages in one connection", host_and_ident(TRUE));
2688 /* Reset for start of message - even if this is going to fail, we
2689 obviously need to throw away any previous data. */
2691 smtp_reset(reset_point);
2693 sender_data = recipient_data = NULL;
2695 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2699 uschar *name, *value, *end;
2700 unsigned long int size;
2702 if (!extract_option(&name, &value)) break;
2704 /* Handle SIZE= by reading the value. We don't do the check till later,
2705 in order to be able to log the sender address on failure. */
2707 if (strcmpic(name, US"SIZE") == 0 &&
2708 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2710 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2712 message_size = (int)size;
2715 /* If this session was initiated with EHLO and accept_8bitmime is set,
2716 Exim will have indicated that it supports the BODY=8BITMIME option. In
2717 fact, it does not support this according to the RFCs, in that it does not
2718 take any special action for forwarding messages containing 8-bit
2719 characters. That is why accept_8bitmime is not the default setting, but
2720 some sites want the action that is provided. We recognize both "8BITMIME"
2721 and "7BIT" as body types, but take no action. */
2723 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2724 (strcmpic(value, US"8BITMIME") == 0 ||
2725 strcmpic(value, US"7BIT") == 0)) {}
2727 /* Handle the AUTH extension. If the value given is not "<>" and either
2728 the ACL says "yes" or there is no ACL but the sending host is
2729 authenticated, we set it up as the authenticated sender. However, if the
2730 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2731 the condition is met. The value of AUTH is an xtext, which means that +,
2732 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2735 else if (strcmpic(name, US"AUTH") == 0)
2737 if (Ustrcmp(value, "<>") != 0)
2742 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2744 /* Put back terminator overrides for error message */
2747 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2748 US"invalid data for AUTH");
2752 if (acl_smtp_mailauth == NULL)
2754 ignore_msg = US"client not authenticated";
2755 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2759 ignore_msg = US"rejected by ACL";
2760 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2761 &user_msg, &log_msg);
2767 if (authenticated_by == NULL ||
2768 authenticated_by->mail_auth_condition == NULL ||
2769 expand_check_condition(authenticated_by->mail_auth_condition,
2770 authenticated_by->name, US"authenticator"))
2771 break; /* Accept the AUTH */
2773 ignore_msg = US"server_mail_auth_condition failed";
2774 if (authenticated_id != NULL)
2775 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2776 ignore_msg, authenticated_id);
2781 authenticated_sender = NULL;
2782 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2783 value, host_and_ident(TRUE), ignore_msg);
2786 /* Should only get DEFER or ERROR here. Put back terminator
2787 overrides for error message */
2792 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2799 /* Unknown option. Stick back the terminator characters and break
2800 the loop. An error for a malformed address will occur. */
2810 /* If we have passed the threshold for rate limiting, apply the current
2811 delay, and update it for next time, provided this is a limited host. */
2813 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2814 verify_check_host(&smtp_ratelimit_hosts) == OK)
2816 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2817 smtp_delay_mail/1000.0);
2818 millisleep((int)smtp_delay_mail);
2819 smtp_delay_mail *= smtp_rlm_factor;
2820 if (smtp_delay_mail > (double)smtp_rlm_limit)
2821 smtp_delay_mail = (double)smtp_rlm_limit;
2824 /* Now extract the address, first applying any SMTP-time rewriting. The
2825 TRUE flag allows "<>" as a sender address. */
2827 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2828 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
2829 global_rewrite_rules) : smtp_cmd_argument;
2831 /* rfc821_domains = TRUE; << no longer needed */
2833 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2835 /* rfc821_domains = FALSE; << no longer needed */
2837 if (raw_sender == NULL)
2839 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
2843 sender_address = raw_sender;
2845 /* If there is a configured size limit for mail, check that this message
2846 doesn't exceed it. The check is postponed to this point so that the sender
2849 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2851 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2852 log_write(L_size_reject,
2853 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2854 "message too big: size%s=%d max=%d",
2856 host_and_ident(TRUE),
2857 (message_size == INT_MAX)? ">" : "",
2859 thismessage_size_limit);
2860 sender_address = NULL;
2864 /* Check there is enough space on the disk unless configured not to.
2865 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2866 plus the current message - i.e. we accept the message only if it won't
2867 reduce the space below the threshold. Add 5000 to the size to allow for
2868 overheads such as the Received: line and storing of recipients, etc.
2869 By putting the check here, even when SIZE is not given, it allow VRFY
2870 and EXPN etc. to be used when space is short. */
2872 if (!receive_check_fs(
2873 (smtp_check_spool_space && message_size >= 0)?
2874 message_size + 5000 : 0))
2876 smtp_printf("452 Space shortage, please try later\r\n");
2877 sender_address = NULL;
2881 /* If sender_address is unqualified, reject it, unless this is a locally
2882 generated message, or the sending host or net is permitted to send
2883 unqualified addresses - typically local machines behaving as MUAs -
2884 in which case just qualify the address. The flag is set above at the start
2885 of the SMTP connection. */
2887 if (sender_domain == 0 && sender_address[0] != 0)
2889 if (allow_unqualified_sender)
2891 sender_domain = Ustrlen(sender_address) + 1;
2892 sender_address = rewrite_address_qualify(sender_address, FALSE);
2893 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2898 smtp_printf("501 %s: sender address must contain a domain\r\n",
2900 log_write(L_smtp_syntax_error,
2901 LOG_MAIN|LOG_REJECT,
2902 "unqualified sender rejected: <%s> %s%s",
2904 host_and_ident(TRUE),
2906 sender_address = NULL;
2911 /* Apply an ACL check if one is defined, before responding */
2913 rc = (acl_smtp_mail == NULL)? OK :
2914 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2916 if (rc == OK || rc == DISCARD)
2918 smtp_printf("250 OK\r\n");
2919 smtp_delay_rcpt = smtp_rlr_base;
2920 recipients_discarded = (rc == DISCARD);
2921 was_rej_mail = FALSE;
2926 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2927 sender_address = NULL;
2932 /* The RCPT command requires an address as an operand. All we do
2933 here is to parse it for syntactic correctness. There may be any number
2934 of RCPT commands, specifying multiple senders. We build them all into
2935 a data structure that is in argc/argv format. The start/end values
2936 given by parse_extract_address are not used, as we keep only the
2937 extracted address. */
2943 /* There must be a sender address; if the sender was rejected and
2944 pipelining was advertised, we assume the client was pipelining, and do not
2945 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2946 get the same treatment. */
2948 if (sender_address == NULL)
2950 if (pipelining_advertised && last_was_rej_mail)
2952 smtp_printf("503 sender not yet given\r\n");
2953 was_rej_mail = TRUE;
2957 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2958 US"sender not yet given");
2959 was_rcpt = FALSE; /* Not a valid RCPT */
2965 /* Check for an operand */
2967 if (smtp_cmd_argument[0] == 0)
2969 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2970 US"RCPT must have an address operand");
2975 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2976 as a recipient address */
2978 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2979 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
2980 global_rewrite_rules) : smtp_cmd_argument;
2982 /* rfc821_domains = TRUE; << no longer needed */
2983 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2984 &recipient_domain, FALSE);
2985 /* rfc821_domains = FALSE; << no longer needed */
2987 if (recipient == NULL)
2989 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
2994 /* If the recipient address is unqualified, reject it, unless this is a
2995 locally generated message. However, unqualified addresses are permitted
2996 from a configured list of hosts and nets - typically when behaving as
2997 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2998 really. The flag is set at the start of the SMTP connection.
3000 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3001 assumed this meant "reserved local part", but the revision of RFC 821 and
3002 friends now makes it absolutely clear that it means *mailbox*. Consequently
3003 we must always qualify this address, regardless. */
3005 if (recipient_domain == 0)
3007 if (allow_unqualified_recipient ||
3008 strcmpic(recipient, US"postmaster") == 0)
3010 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3012 recipient_domain = Ustrlen(recipient) + 1;
3013 recipient = rewrite_address_qualify(recipient, TRUE);
3018 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3020 log_write(L_smtp_syntax_error,
3021 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3022 "<%s> %s%s", recipient, host_and_ident(TRUE),
3028 /* Check maximum allowed */
3030 if (rcpt_count > recipients_max && recipients_max > 0)
3032 if (recipients_max_reject)
3035 smtp_printf("552 too many recipients\r\n");
3037 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3038 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3043 smtp_printf("452 too many recipients\r\n");
3045 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3046 "temporarily rejected: sender=<%s> %s", sender_address,
3047 host_and_ident(TRUE));
3054 /* If we have passed the threshold for rate limiting, apply the current
3055 delay, and update it for next time, provided this is a limited host. */
3057 if (rcpt_count > smtp_rlr_threshold &&
3058 verify_check_host(&smtp_ratelimit_hosts) == OK)
3060 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3061 smtp_delay_rcpt/1000.0);
3062 millisleep((int)smtp_delay_rcpt);
3063 smtp_delay_rcpt *= smtp_rlr_factor;
3064 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3065 smtp_delay_rcpt = (double)smtp_rlr_limit;
3068 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3069 for them. Otherwise, check the access control list for this recipient. */
3071 rc = recipients_discarded? DISCARD :
3072 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3074 /* The ACL was happy */
3078 smtp_printf("250 Accepted\r\n");
3079 receive_add_recipient(recipient, -1);
3082 /* The recipient was discarded */
3084 else if (rc == DISCARD)
3086 smtp_printf("250 Accepted\r\n");
3089 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3090 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3091 (sender_address_unrewritten != NULL)?
3092 sender_address_unrewritten : sender_address,
3093 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3094 (log_msg == NULL)? US"" : US": ",
3095 (log_msg == NULL)? US"" : log_msg);
3098 /* Either the ACL failed the address, or it was deferred. */
3102 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3103 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3108 /* The DATA command is legal only if it follows successful MAIL FROM
3109 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3110 not counted as a protocol error if it follows RCPT (which must have been
3111 rejected if there are no recipients.) This function is complete when a
3112 valid DATA command is encountered.
3114 Note concerning the code used: RFC 2821 says this:
3116 - If there was no MAIL, or no RCPT, command, or all such commands
3117 were rejected, the server MAY return a "command out of sequence"
3118 (503) or "no valid recipients" (554) reply in response to the
3121 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3122 because it is the same whether pipelining is in use or not. */
3125 if (!discarded && recipients_count <= 0)
3127 if (pipelining_advertised && last_was_rcpt)
3128 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3130 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3131 US"valid RCPT command must precede DATA");
3135 if (toomany && recipients_max_reject)
3137 sender_address = NULL; /* This will allow a new MAIL without RSET */
3138 sender_address_unrewritten = NULL;
3139 smtp_printf("554 Too many recipients\r\n");
3143 if (acl_smtp_predata == NULL) rc = OK; else
3145 enable_dollar_recipients = TRUE;
3146 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3148 enable_dollar_recipients = FALSE;
3153 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3155 message_ended = END_NOTENDED; /* Indicate in middle of data */
3158 /* Either the ACL failed the address, or it was deferred. */
3161 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3167 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3169 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3175 /* rfc821_domains = TRUE; << no longer needed */
3176 address = parse_extract_address(smtp_cmd_argument, &errmess, &start, &end,
3177 &recipient_domain, FALSE);
3178 /* rfc821_domains = FALSE; << no longer needed */
3180 if (address == NULL)
3181 s = string_sprintf("501 %s", errmess);
3184 address_item *addr = deliver_make_addr(address, FALSE);
3185 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3186 -1, -1, NULL, NULL, NULL))
3189 s = string_sprintf("250 <%s> is deliverable", address);
3193 s = (addr->message != NULL)?
3194 string_sprintf("451 <%s> %s", address, addr->message) :
3195 string_sprintf("451 Cannot resolve <%s> at this time", address);
3199 s = (addr->message != NULL)?
3200 string_sprintf("550 <%s> %s", address, addr->message) :
3201 string_sprintf("550 <%s> is not deliverable", address);
3202 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3203 smtp_cmd_argument, host_and_ident(TRUE));
3208 smtp_printf("%s\r\n", s);
3214 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3216 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3219 BOOL save_log_testing_mode = log_testing_mode;
3220 address_test_mode = log_testing_mode = TRUE;
3221 (void) verify_address(deliver_make_addr(smtp_cmd_argument, FALSE),
3222 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3224 address_test_mode = FALSE;
3225 log_testing_mode = save_log_testing_mode; /* true for -bh */
3233 if (!tls_advertised)
3235 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3236 US"STARTTLS command used when not advertised");
3240 /* Apply an ACL check if one is defined */
3242 if (acl_smtp_starttls != NULL)
3244 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3248 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3253 /* RFC 2487 is not clear on when this command may be sent, though it
3254 does state that all information previously obtained from the client
3255 must be discarded if a TLS session is started. It seems reasonble to
3256 do an implied RSET when STARTTLS is received. */
3258 incomplete_transaction_log(US"STARTTLS");
3259 smtp_reset(reset_point);
3261 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3263 /* Attempt to start up a TLS session, and if successful, discard all
3264 knowledge that was obtained previously. At least, that's what the RFC says,
3265 and that's what happens by default. However, in order to work round YAEB,
3266 there is an option to remember the esmtp state. Sigh.
3268 We must allow for an extra EHLO command and an extra AUTH command after
3269 STARTTLS that don't add to the nonmail command count. */
3271 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3273 if (!tls_remember_esmtp)
3274 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3275 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3276 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3277 if (sender_helo_name != NULL)
3279 store_free(sender_helo_name);
3280 sender_helo_name = NULL;
3281 host_build_sender_fullhost(); /* Rebuild */
3282 set_process_info("handling incoming TLS connection from %s",
3283 host_and_ident(FALSE));
3285 received_protocol = (esmtp?
3286 protocols[pextend + pcrpted +
3287 ((sender_host_authenticated != NULL)? pauthed : 0)]
3289 protocols[pnormal + pcrpted])
3291 ((sender_host_address != NULL)? pnlocal : 0);
3293 sender_host_authenticated = NULL;
3294 authenticated_id = NULL;
3295 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3296 DEBUG(D_tls) debug_printf("TLS active\n");
3297 break; /* Successful STARTTLS */
3300 /* Some local configuration problem was discovered before actually trying
3301 to do a TLS handshake; give a temporary error. */
3303 else if (rc == DEFER)
3305 smtp_printf("454 TLS currently unavailable\r\n");
3309 /* Hard failure. Reject everything except QUIT or closed connection. One
3310 cause for failure is a nested STARTTLS, in which case tls_active remains
3311 set, but we must still reject all incoming commands. */
3313 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3316 switch(smtp_read_command(FALSE))
3319 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3320 smtp_get_connection_info());
3325 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3326 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3327 smtp_get_connection_info());
3332 smtp_printf("554 Security failure\r\n");
3341 /* The ACL for QUIT is provided for gathering statistical information or
3342 similar; it does not affect the response code, but it can supply a custom
3346 incomplete_transaction_log(US"QUIT");
3348 if (acl_smtp_quit != NULL)
3350 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit,&user_msg,&log_msg);
3352 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3355 else user_msg = NULL;
3357 if (user_msg == NULL)
3358 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3360 smtp_printf("221 %s\r\n", user_msg);
3367 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3368 smtp_get_connection_info());
3373 incomplete_transaction_log(US"RSET");
3374 smtp_reset(reset_point);
3376 smtp_printf("250 Reset OK\r\n");
3377 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3382 smtp_printf("250 OK\r\n");
3386 /* Show ETRN/EXPN/VRFY if there's
3387 an ACL for checking hosts; if actually used, a check will be done for
3391 smtp_printf("214-Commands supported:\r\n");
3395 Ustrcat(buffer, " AUTH");
3397 Ustrcat(buffer, " STARTTLS");
3399 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3400 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3401 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3402 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3403 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3404 smtp_printf("214%s\r\n", buffer);
3410 incomplete_transaction_log(US"connection lost");
3411 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3413 /* Don't log by default unless in the middle of a message, as some mailers
3414 just drop the call rather than sending QUIT, and it clutters up the logs.
3417 if (sender_address != NULL || recipients_count > 0)
3418 log_write(L_lost_incoming_connection,
3420 "unexpected %s while reading SMTP command from %s%s",
3421 sender_host_unknown? "EOF" : "disconnection",
3422 host_and_ident(FALSE), smtp_read_error);
3424 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3425 smtp_get_connection_info(), smtp_read_error);
3432 if (sender_address != NULL)
3434 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3435 US"ETRN is not permitted inside a transaction");
3439 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
3440 host_and_ident(FALSE));
3442 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
3445 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3449 /* Compute the serialization key for this command. */
3451 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_argument);
3453 /* If a command has been specified for running as a result of ETRN, we
3454 permit any argument to ETRN. If not, only the # standard form is permitted,
3455 since that is strictly the only kind of ETRN that can be implemented
3456 according to the RFC. */
3458 if (smtp_etrn_command != NULL)
3462 etrn_command = smtp_etrn_command;
3463 deliver_domain = smtp_cmd_argument;
3464 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3465 US"ETRN processing", &error);
3466 deliver_domain = NULL;
3469 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3471 smtp_printf("458 Internal failure\r\n");
3476 /* Else set up to call Exim with the -R option. */
3480 if (*smtp_cmd_argument++ != '#')
3482 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3483 US"argument must begin with #");
3486 etrn_command = US"exim -R";
3487 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3491 /* If we are host-testing, don't actually do anything. */
3497 debug_printf("ETRN command is: %s\n", etrn_command);
3498 debug_printf("ETRN command execution skipped\n");
3500 smtp_printf("250 OK\r\n");
3505 /* If ETRN queue runs are to be serialized, check the database to
3506 ensure one isn't already running. */
3508 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3510 smtp_printf("458 Already processing %s\r\n", smtp_cmd_argument);
3514 /* Fork a child process and run the command. We don't want to have to
3515 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3516 forking. It should be set that way anyway for external incoming SMTP,
3517 but we save and restore to be tidy. If serialization is required, we
3518 actually run the command in yet another process, so we can wait for it
3519 to complete and then remove the serialization lock. */
3521 oldsignal = signal(SIGCHLD, SIG_IGN);
3523 if ((pid = fork()) == 0)
3525 smtp_input = FALSE; /* This process is not associated with the */
3526 (void)fclose(smtp_in); /* SMTP call any more. */
3527 (void)fclose(smtp_out);
3529 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3531 /* If not serializing, do the exec right away. Otherwise, fork down
3532 into another process. */
3534 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3536 DEBUG(D_exec) debug_print_argv(argv);
3537 exim_nullstd(); /* Ensure std{in,out,err} exist */
3538 execv(CS argv[0], (char *const *)argv);
3539 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3540 etrn_command, strerror(errno));
3541 _exit(EXIT_FAILURE); /* paranoia */
3544 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3545 is, we are in the first subprocess, after forking again. All we can do
3546 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3547 complete, before removing the serialization. */
3550 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3551 "failed: %s", strerror(errno));
3555 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3557 (void)wait(&status);
3558 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3562 enq_end(etrn_serialize_key);
3563 _exit(EXIT_SUCCESS);
3566 /* Back in the top level SMTP process. Check that we started a subprocess
3567 and restore the signal state. */
3571 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3573 smtp_printf("458 Unable to fork process\r\n");
3574 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3576 else smtp_printf("250 OK\r\n");
3578 signal(SIGCHLD, oldsignal);
3583 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3584 US"unexpected argument data");
3588 /* This currently happens only for NULLs, but could be extended. */
3591 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3592 US"NULL character(s) present (shown as '?')");
3593 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3598 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3599 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3600 c = smtp_inend - smtp_inptr;
3601 if (c > 150) c = 150;
3603 incomplete_transaction_log(US"sync failure");
3604 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
3605 "(next input sent too soon: pipelining was%s advertised): "
3606 "rejected \"%s\" %s next input=\"%s\"",
3607 pipelining_advertised? "" : " not",
3608 smtp_cmd_buffer, host_and_ident(TRUE),
3609 string_printing(smtp_inptr));
3610 smtp_printf("554 SMTP synchronization error\r\n");
3611 done = 1; /* Pretend eof - drops connection */
3615 case TOO_MANY_NONMAIL_CMD:
3616 incomplete_transaction_log(US"too many non-mail commands");
3617 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3618 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
3619 smtp_cmd_argument - smtp_cmd_buffer, smtp_cmd_buffer);
3620 smtp_printf("554 Too many nonmail commands\r\n");
3621 done = 1; /* Pretend eof - drops connection */
3626 if (unknown_command_count++ >= smtp_max_unknown_commands)
3628 log_write(L_smtp_syntax_error, LOG_MAIN,
3629 "SMTP syntax error in \"%s\" %s %s",
3630 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
3631 US"unrecognized command");
3632 incomplete_transaction_log(US"unrecognized command");
3633 smtp_printf("500 Too many unrecognized commands\r\n");
3635 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3636 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3640 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3641 US"unrecognized command");
3645 /* This label is used by goto's inside loops that want to break out to
3646 the end of the command-processing loop. */
3649 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3650 last_was_rcpt = was_rcpt; /* protocol error handling */
3654 return done - 2; /* Convert yield values */
3657 /* End of smtp_in.c */