1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.25 2005/09/12 10:08:54 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2005 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. */
42 #define cmd_buffer_size 2048
44 /* Size of buffer for reading SMTP incoming packets */
46 #define in_buffer_size 8192
48 /* Structure for SMTP command list */
55 short int is_mail_cmd;
58 /* Codes for identifying commands. We order them so that those that come first
59 are those for which synchronization is always required. Checking this can help
63 /* These commands are required to be synchronized, i.e. to be the last in a
64 block of commands when pipelining. */
66 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
67 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
68 ETRN_CMD, /* This by analogy with TURN from the RFC */
69 STARTTLS_CMD, /* Required by the STARTTLS RFC */
71 /* This is a dummy to identify the non-sync commands when pipelining */
73 NON_SYNC_CMD_PIPELINING,
75 /* These commands need not be synchronized when pipelining */
77 MAIL_CMD, RCPT_CMD, RSET_CMD,
79 /* This is a dummy to identify the non-sync commands when not pipelining */
81 NON_SYNC_CMD_NON_PIPELINING,
83 /* I have been unable to find a statement about the use of pipelining
84 with AUTH, so to be on the safe side it is here, though I kind of feel
85 it should be up there with the synchronized commands. */
89 /* I'm not sure about these, but I don't think they matter. */
93 /* These are specials that don't correspond to actual commands */
95 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
96 TOO_MANY_NONMAIL_CMD };
100 /*************************************************
101 * Local static variables *
102 *************************************************/
104 static auth_instance *authenticated_by;
105 static BOOL auth_advertised;
107 static BOOL tls_advertised;
110 static BOOL helo_required = FALSE;
111 static BOOL helo_verify = FALSE;
112 static BOOL helo_seen;
113 static BOOL helo_accept_junk;
114 static BOOL count_nonmail;
115 static BOOL pipelining_advertised;
116 static int nonmail_command_count;
117 static int synprot_error_count;
118 static int unknown_command_count;
119 static int sync_cmd_limit;
120 static int smtp_write_error = 0;
122 static uschar *cmd_buffer;
124 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
125 final fields of all except AUTH are forced TRUE at the start of a new message
126 setup, to allow one of each between messages that is not counted as a nonmail
127 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
128 allow a new EHLO after starting up TLS.
130 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
131 counted. However, the flag is changed when AUTH is received, so that multiple
132 failing AUTHs will eventually hit the limit. After a successful AUTH, another
133 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
134 forced TRUE, to allow for the re-authentication that can happen at that point.
136 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
137 count of non-mail commands and possibly provoke an error. */
139 static smtp_cmd_list cmd_list[] = {
140 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
141 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
142 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
143 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
145 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
148 /* If you change anything above here, also fix the definitions below. */
150 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
151 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
152 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
153 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
154 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
155 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
156 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
157 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
158 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
161 static smtp_cmd_list *cmd_list_end =
162 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
164 #define CMD_LIST_RSET 0
165 #define CMD_LIST_HELO 1
166 #define CMD_LIST_EHLO 2
167 #define CMD_LIST_AUTH 3
168 #define CMD_LIST_STARTTLS 4
170 static uschar *protocols[] = {
171 US"local-smtp", /* HELO */
172 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
173 US"local-esmtp", /* EHLO */
174 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
175 US"local-esmtpa", /* EHLO->AUTH */
176 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
181 #define pcrpted 1 /* added to pextend or pnormal */
182 #define pauthed 2 /* added to pextend */
183 #define pnlocal 6 /* offset to remove "local" */
185 /* When reading SMTP from a remote host, we have to use our own versions of the
186 C input-reading functions, in order to be able to flush the SMTP output only
187 when about to read more data from the socket. This is the only way to get
188 optimal performance when the client is using pipelining. Flushing for every
189 command causes a separate packet and reply packet each time; saving all the
190 responses up (when pipelining) combines them into one packet and one response.
192 For simplicity, these functions are used for *all* SMTP input, not only when
193 receiving over a socket. However, after setting up a secure socket (SSL), input
194 is read via the OpenSSL library, and another set of functions is used instead
197 These functions are set in the receive_getc etc. variables and called with the
198 same interface as the C functions. However, since there can only ever be
199 one incoming SMTP call, we just use a single buffer and flags. There is no need
200 to implement a complicated private FILE-like structure.*/
202 static uschar *smtp_inbuffer;
203 static uschar *smtp_inptr;
204 static uschar *smtp_inend;
205 static int smtp_had_eof;
206 static int smtp_had_error;
209 /*************************************************
210 * SMTP version of getc() *
211 *************************************************/
213 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
214 it flushes the output, and refills the buffer, with a timeout. The signal
215 handler is set appropriately by the calling function. This function is not used
216 after a connection has negotated itself into an TLS/SSL state.
219 Returns: the next character or EOF
225 if (smtp_inptr >= smtp_inend)
229 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
230 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
235 /* Must put the error text in fixed store, because this might be during
236 header reading, where it releases unused store above the header. */
239 smtp_had_error = save_errno;
240 smtp_read_error = string_copy_malloc(
241 string_sprintf(" (error: %s)", strerror(save_errno)));
243 else smtp_had_eof = 1;
246 smtp_inend = smtp_inbuffer + rc;
247 smtp_inptr = smtp_inbuffer;
249 return *smtp_inptr++;
254 /*************************************************
255 * SMTP version of ungetc() *
256 *************************************************/
258 /* Puts a character back in the input buffer. Only ever
264 Returns: the character
270 *(--smtp_inptr) = ch;
277 /*************************************************
278 * SMTP version of feof() *
279 *************************************************/
281 /* Tests for a previous EOF
284 Returns: non-zero if the eof flag is set
296 /*************************************************
297 * SMTP version of ferror() *
298 *************************************************/
300 /* Tests for a previous read error, and returns with errno
301 restored to what it was when the error was detected.
304 Returns: non-zero if the error flag is set
310 errno = smtp_had_error;
311 return smtp_had_error;
317 /*************************************************
318 * Write formatted string to SMTP channel *
319 *************************************************/
321 /* This is a separate function so that we don't have to repeat everything for
322 TLS support or debugging. It is global so that the daemon and the
323 authentication functions can use it. It does not return any error indication,
324 because major problems such as dropped connections won't show up till an output
325 flush for non-TLS connections. The smtp_fflush() function is available for
326 checking that: for convenience, TLS output errors are remembered here so that
327 they are also picked up later by smtp_fflush().
331 ... optional arguments
337 smtp_printf(char *format, ...)
343 va_start(ap, format);
344 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
345 debug_printf("SMTP>> %s", big_buffer);
348 va_start(ap, format);
350 /* If in a TLS session we have to format the string, and then write it using a
356 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
358 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
359 smtp_closedown(US"Unexpected error");
360 exim_exit(EXIT_FAILURE);
362 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
367 /* Otherwise, just use the standard library function. */
369 if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
375 /*************************************************
376 * Flush SMTP out and check for error *
377 *************************************************/
379 /* This function isn't currently used within Exim (it detects errors when it
380 tries to read the next SMTP input), but is available for use in local_scan().
381 For non-TLS connections, it flushes the output and checks for errors. For
382 TLS-connections, it checks for a previously-detected TLS write error.
385 Returns: 0 for no error; -1 after an error
391 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
392 return smtp_write_error;
397 /*************************************************
398 * SMTP command read timeout *
399 *************************************************/
401 /* Signal handler for timing out incoming SMTP commands. This attempts to
404 Argument: signal number (SIGALRM)
409 command_timeout_handler(int sig)
411 sig = sig; /* Keep picky compilers happy */
412 log_write(L_lost_incoming_connection,
413 LOG_MAIN, "SMTP command timeout on%s connection from %s",
414 (tls_active >= 0)? " TLS" : "",
415 host_and_ident(FALSE));
416 if (smtp_batched_input)
417 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
418 smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
419 smtp_active_hostname);
421 exim_exit(EXIT_FAILURE);
426 /*************************************************
428 *************************************************/
430 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
432 Argument: signal number (SIGTERM)
437 command_sigterm_handler(int sig)
439 sig = sig; /* Keep picky compilers happy */
440 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
441 if (smtp_batched_input)
442 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
443 smtp_printf("421 %s: Service not available - closing connection\r\n",
444 smtp_active_hostname);
445 exim_exit(EXIT_FAILURE);
450 /*************************************************
451 * Read one command line *
452 *************************************************/
454 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
455 There are sites that don't do this, and in any case internal SMTP probably
456 should check only for LF. Consequently, we check here for LF only. The line
457 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
458 an unknown command. The command is read into the static cmd_buffer.
460 The character reading routine sets up a timeout for each block actually read
461 from the input (which may contain more than one command). We set up a special
462 signal handler that closes down the session on a timeout. Control does not
466 check_sync if TRUE, check synchronization rules if global option is TRUE
468 Returns: a code identifying the command (enumerated above)
472 smtp_read_command(BOOL check_sync)
477 BOOL hadnull = FALSE;
479 os_non_restarting_signal(SIGALRM, command_timeout_handler);
481 while ((c = (receive_getc)()) != '\n' && c != EOF)
483 if (ptr >= cmd_buffer_size)
485 os_non_restarting_signal(SIGALRM, sigalrm_handler);
493 cmd_buffer[ptr++] = c;
496 receive_linecount++; /* For BSMTP errors */
497 os_non_restarting_signal(SIGALRM, sigalrm_handler);
499 /* If hit end of file, return pseudo EOF command. Whether we have a
500 part-line already read doesn't matter, since this is an error state. */
502 if (c == EOF) return EOF_CMD;
504 /* Remove any CR and white space at the end of the line, and terminate the
507 while (ptr > 0 && isspace(cmd_buffer[ptr-1])) ptr--;
510 DEBUG(D_receive) debug_printf("SMTP<< %s\n", cmd_buffer);
512 /* NULLs are not allowed in SMTP commands */
514 if (hadnull) return BADCHAR_CMD;
516 /* Scan command list and return identity, having set the data pointer
517 to the start of the actual data characters. Check for SMTP synchronization
520 for (p = cmd_list; p < cmd_list_end; p++)
522 if (strncmpic(cmd_buffer, US p->name, p->len) == 0)
524 if (smtp_inptr < smtp_inend && /* Outstanding input */
525 p->cmd < sync_cmd_limit && /* Command should sync */
526 check_sync && /* Local flag set */
527 smtp_enforce_sync && /* Global flag set */
528 sender_host_address != NULL && /* Not local input */
529 !sender_host_notsocket) /* Really is a socket */
532 /* Point after the command, but don't skip over leading spaces till after
533 the following test, so that if it fails, the command name can easily be
536 smtp_command_argument = cmd_buffer + p->len;
538 /* Count non-mail commands from those hosts that are controlled in this
539 way. The default is all hosts. We don't waste effort checking the list
540 until we get a non-mail command, but then cache the result to save checking
541 again. If there's a DEFER while checking the host, assume it's in the list.
543 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
544 start of each incoming message by fiddling with the value in the table. */
548 if (count_nonmail == TRUE_UNSET) count_nonmail =
549 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
550 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
551 return TOO_MANY_NONMAIL_CMD;
554 /* Get the data pointer over leading spaces and return; if there is data
555 for a command that does not expect it, give the error centrally here. */
557 while (isspace(*smtp_command_argument)) smtp_command_argument++;
558 return (p->has_arg || *smtp_command_argument == 0)? p->cmd : BADARG_CMD;
562 /* Enforce synchronization for unknown commands */
564 if (smtp_inptr < smtp_inend && /* Outstanding input */
565 check_sync && /* Local flag set */
566 smtp_enforce_sync && /* Global flag set */
567 sender_host_address != NULL && /* Not local input */
568 !sender_host_notsocket) /* Really is a socket */
576 /*************************************************
577 * Forced closedown of call *
578 *************************************************/
580 /* This function is called from log.c when Exim is dying because of a serious
581 disaster, and also from some other places. If an incoming non-batched SMTP
582 channel is open, it swallows the rest of the incoming message if in the DATA
583 phase, sends the reply string, and gives an error to all subsequent commands
584 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
587 Argument: SMTP reply string to send, excluding the code
592 smtp_closedown(uschar *message)
594 if (smtp_in == NULL || smtp_batched_input) return;
595 receive_swallow_smtp();
596 smtp_printf("421 %s\r\n", message);
600 switch(smtp_read_command(FALSE))
606 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
611 smtp_printf("250 Reset OK\r\n");
615 smtp_printf("421 %s\r\n", message);
624 /*************************************************
625 * Set up connection info for logging *
626 *************************************************/
628 /* This function is called when logging information about an SMTP connection.
629 It sets up appropriate source information, depending on the type of connection.
632 Returns: a string describing the connection
636 smtp_get_connection_info(void)
639 return string_sprintf("SMTP connection from %s", sender_fullhost);
641 if (sender_host_unknown || sender_host_notsocket)
642 return string_sprintf("SMTP connection from %s", sender_ident);
645 return string_sprintf("SMTP connection from %s (via inetd)", sender_fullhost);
647 if ((log_extra_selector & LX_incoming_interface) != 0 &&
648 interface_address != NULL)
649 return string_sprintf("SMTP connection from %s I=[%s]:%d", sender_fullhost,
650 interface_address, interface_port);
652 return string_sprintf("SMTP connection from %s", sender_fullhost);
657 /*************************************************
658 * Check HELO line and set sender_helo_name *
659 *************************************************/
661 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
662 the domain name of the sending host, or an ip literal in square brackets. The
663 arrgument is placed in sender_helo_name, which is in malloc store, because it
664 must persist over multiple incoming messages. If helo_accept_junk is set, this
665 host is permitted to send any old junk (needed for some broken hosts).
666 Otherwise, helo_allow_chars can be used for rogue characters in general
667 (typically people want to let in underscores).
670 s the data portion of the line (already past any white space)
672 Returns: TRUE or FALSE
676 check_helo(uschar *s)
679 uschar *end = s + Ustrlen(s);
680 BOOL yield = helo_accept_junk;
682 /* Discard any previous helo name */
684 if (sender_helo_name != NULL)
686 store_free(sender_helo_name);
687 sender_helo_name = NULL;
690 /* Skip tests if junk is permitted. */
694 /* Allow the new standard form for IPv6 address literals, namely,
695 [IPv6:....], and because someone is bound to use it, allow an equivalent
696 IPv4 form. Allow plain addresses as well. */
703 if (strncmpic(s, US"[IPv6:", 6) == 0)
704 yield = (string_is_ip_address(s+6, NULL) == 6);
705 else if (strncmpic(s, US"[IPv4:", 6) == 0)
706 yield = (string_is_ip_address(s+6, NULL) == 4);
708 yield = (string_is_ip_address(s+1, NULL) != 0);
713 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
714 that have been configured (usually underscore - sigh). */
721 if (!isalnum(*s) && *s != '.' && *s != '-' &&
722 Ustrchr(helo_allow_chars, *s) == NULL)
732 /* Save argument if OK */
734 if (yield) sender_helo_name = string_copy_malloc(start);
742 /*************************************************
743 * Extract SMTP command option *
744 *************************************************/
746 /* This function picks the next option setting off the end of smtp_command_argument. It
747 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
748 things that can appear there.
751 name point this at the name
752 value point this at the data string
754 Returns: TRUE if found an option
758 extract_option(uschar **name, uschar **value)
761 uschar *v = smtp_command_argument + Ustrlen(smtp_command_argument) -1;
762 while (isspace(*v)) v--;
765 while (v > smtp_command_argument && *v != '=' && !isspace(*v)) v--;
766 if (*v != '=') return FALSE;
769 while(isalpha(n[-1])) n--;
771 if (n[-1] != ' ') return FALSE;
786 /*************************************************
787 * Reset for new message *
788 *************************************************/
790 /* This function is called whenever the SMTP session is reset from
791 within either of the setup functions.
793 Argument: the stacking pool storage reset point
798 smtp_reset(void *reset_point)
801 store_reset(reset_point);
802 recipients_list = NULL;
803 rcpt_count = rcpt_defer_count = rcpt_fail_count =
804 raw_recipients_count = recipients_count = recipients_list_max = 0;
805 message_linecount = 0;
807 acl_warn_headers = NULL;
808 queue_only_policy = FALSE;
809 deliver_freeze = FALSE; /* Can be set by ACL */
810 fake_response = OK; /* Can be set by ACL */
811 #ifdef WITH_CONTENT_SCAN
812 no_mbox_unspool = FALSE; /* Can be set by ACL */
814 submission_mode = FALSE; /* Can be set by ACL */
815 suppress_local_fixups = FALSE; /* Can be set by ACL */
816 active_local_from_check = local_from_check; /* Can be set by ACL */
817 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
818 sender_address = NULL;
819 submission_name = NULL; /* Can be set by ACL */
820 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
821 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
822 sender_verified_list = NULL; /* No senders verified */
823 memset(sender_address_cache, 0, sizeof(sender_address_cache));
824 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
825 authenticated_sender = NULL;
826 #ifdef EXPERIMENTAL_BRIGHTMAIL
830 #ifdef EXPERIMENTAL_DOMAINKEYS
833 #ifdef EXPERIMENTAL_SPF
834 spf_header_comment = NULL;
837 spf_smtp_comment = NULL;
839 body_linecount = body_zerocount = 0;
841 sender_rate = sender_rate_limit = sender_rate_period = NULL;
842 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
843 /* Note that ratelimiters_conn persists across resets. */
845 for (i = 0; i < ACL_M_MAX; i++) acl_var[ACL_C_MAX + i] = NULL;
847 /* The message body variables use malloc store. They may be set if this is
848 not the first message in an SMTP session and the previous message caused them
849 to be referenced in an ACL. */
851 if (message_body != NULL)
853 store_free(message_body);
857 if (message_body_end != NULL)
859 store_free(message_body_end);
860 message_body_end = NULL;
863 /* Warning log messages are also saved in malloc store. They are saved to avoid
864 repetition in the same message, but it seems right to repeat them for different
867 while (acl_warn_logged != NULL)
869 string_item *this = acl_warn_logged;
870 acl_warn_logged = acl_warn_logged->next;
879 /*************************************************
880 * Initialize for incoming batched SMTP message *
881 *************************************************/
883 /* This function is called from smtp_setup_msg() in the case when
884 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
885 of messages in one file with SMTP commands between them. All errors must be
886 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
887 relevant. After an error on a sender, or an invalid recipient, the remainder
888 of the message is skipped. The value of received_protocol is already set.
891 Returns: > 0 message successfully started (reached DATA)
892 = 0 QUIT read or end of file reached
897 smtp_setup_batch_msg(void)
900 void *reset_point = store_get(0);
902 /* Save the line count at the start of each transaction - single commands
903 like HELO and RSET count as whole transactions. */
905 bsmtp_transaction_linecount = receive_linecount;
907 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
909 smtp_reset(reset_point); /* Reset for start of message */
911 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
912 value. The values are 2 larger than the required yield of the function. */
917 uschar *recipient = NULL;
918 int start, end, sender_domain, recipient_domain;
920 switch(smtp_read_command(FALSE))
922 /* The HELO/EHLO commands set sender_address_helo if they have
923 valid data; otherwise they are ignored, except that they do
924 a reset of the state. */
929 check_helo(smtp_command_argument);
933 smtp_reset(reset_point);
934 bsmtp_transaction_linecount = receive_linecount;
938 /* The MAIL FROM command requires an address as an operand. All we
939 do here is to parse it for syntactic correctness. The form "<>" is
940 a special case which converts into an empty string. The start/end
941 pointers in the original are not used further for this address, as
942 it is the canonical extracted address which is all that is kept. */
945 if (sender_address != NULL)
946 /* The function moan_smtp_batch() does not return. */
947 moan_smtp_batch(cmd_buffer, "503 Sender already given");
949 if (smtp_command_argument[0] == 0)
950 /* The function moan_smtp_batch() does not return. */
951 moan_smtp_batch(cmd_buffer, "501 MAIL FROM must have an address operand");
953 /* Reset to start of message */
955 smtp_reset(reset_point);
957 /* Apply SMTP rewrite */
959 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
960 rewrite_one(smtp_command_argument, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
961 US"", global_rewrite_rules) : smtp_command_argument;
963 /* Extract the address; the TRUE flag allows <> as valid */
966 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
969 if (raw_sender == NULL)
970 /* The function moan_smtp_batch() does not return. */
971 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
973 sender_address = string_copy(raw_sender);
975 /* Qualify unqualified sender addresses if permitted to do so. */
977 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
979 if (allow_unqualified_sender)
981 sender_address = rewrite_address_qualify(sender_address, FALSE);
982 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
983 "and rewritten\n", raw_sender);
985 /* The function moan_smtp_batch() does not return. */
986 else moan_smtp_batch(cmd_buffer, "501 sender address must contain "
992 /* The RCPT TO command requires an address as an operand. All we do
993 here is to parse it for syntactic correctness. There may be any number
994 of RCPT TO commands, specifying multiple senders. We build them all into
995 a data structure that is in argc/argv format. The start/end values
996 given by parse_extract_address are not used, as we keep only the
997 extracted address. */
1000 if (sender_address == NULL)
1001 /* The function moan_smtp_batch() does not return. */
1002 moan_smtp_batch(cmd_buffer, "503 No sender yet given");
1004 if (smtp_command_argument[0] == 0)
1005 /* The function moan_smtp_batch() does not return. */
1006 moan_smtp_batch(cmd_buffer, "501 RCPT TO must have an address operand");
1008 /* Check maximum number allowed */
1010 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1011 /* The function moan_smtp_batch() does not return. */
1012 moan_smtp_batch(cmd_buffer, "%s too many recipients",
1013 recipients_max_reject? "552": "452");
1015 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1016 recipient address */
1018 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1019 rewrite_one(smtp_command_argument, rewrite_smtp, NULL, FALSE, US"",
1020 global_rewrite_rules) : smtp_command_argument;
1022 /* rfc821_domains = TRUE; << no longer needed */
1023 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1024 &recipient_domain, FALSE);
1025 /* rfc821_domains = FALSE; << no longer needed */
1027 if (recipient == NULL)
1028 /* The function moan_smtp_batch() does not return. */
1029 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
1031 /* If the recipient address is unqualified, qualify it if permitted. Then
1032 add it to the list of recipients. */
1034 if (recipient_domain == 0)
1036 if (allow_unqualified_recipient)
1038 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1040 recipient = rewrite_address_qualify(recipient, TRUE);
1042 /* The function moan_smtp_batch() does not return. */
1043 else moan_smtp_batch(cmd_buffer, "501 recipient address must contain "
1046 receive_add_recipient(recipient, -1);
1050 /* The DATA command is legal only if it follows successful MAIL FROM
1051 and RCPT TO commands. This function is complete when a valid DATA
1052 command is encountered. */
1055 if (sender_address == NULL || recipients_count <= 0)
1057 /* The function moan_smtp_batch() does not return. */
1058 if (sender_address == NULL)
1059 moan_smtp_batch(cmd_buffer,
1060 "503 MAIL FROM:<sender> command must precede DATA");
1062 moan_smtp_batch(cmd_buffer,
1063 "503 RCPT TO:<recipient> must precede DATA");
1067 done = 3; /* DATA successfully achieved */
1068 message_ended = END_NOTENDED; /* Indicate in middle of message */
1073 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1080 bsmtp_transaction_linecount = receive_linecount;
1091 /* The function moan_smtp_batch() does not return. */
1092 moan_smtp_batch(cmd_buffer, "501 Unexpected argument data");
1097 /* The function moan_smtp_batch() does not return. */
1098 moan_smtp_batch(cmd_buffer, "501 Unexpected NULL in SMTP command");
1103 /* The function moan_smtp_batch() does not return. */
1104 moan_smtp_batch(cmd_buffer, "500 Command unrecognized");
1109 return done - 2; /* Convert yield values */
1115 /*************************************************
1116 * Start an SMTP session *
1117 *************************************************/
1119 /* This function is called at the start of an SMTP session. Thereafter,
1120 smtp_setup_msg() is called to initiate each separate message. This
1121 function does host-specific testing, and outputs the banner line.
1124 Returns: FALSE if the session can not continue; something has
1125 gone wrong, or the connection to the host is blocked
1129 smtp_start_session(void)
1135 /* If we are running in the test harness, and the incoming call is from
1136 127.0.0.2 (sic), have a short delay. This makes it possible to test handling of
1137 input sent too soon (before the banner is output). */
1139 if (running_in_test_harness &&
1140 sender_host_address != NULL &&
1141 Ustrcmp(sender_host_address, "127.0.0.2") == 0)
1144 /* Default values for certain variables */
1146 helo_seen = esmtp = helo_accept_junk = FALSE;
1147 count_nonmail = TRUE_UNSET;
1148 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1149 smtp_delay_mail = smtp_rlm_base;
1150 auth_advertised = FALSE;
1151 pipelining_advertised = FALSE;
1152 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1154 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1156 sender_host_authenticated = NULL;
1157 authenticated_by = NULL;
1160 tls_cipher = tls_peerdn = NULL;
1161 tls_advertised = FALSE;
1164 /* Reset ACL connection variables */
1166 for (i = 0; i < ACL_C_MAX; i++) acl_var[i] = NULL;
1168 cmd_buffer = (uschar *)malloc(cmd_buffer_size + 1); /* allow for trailing 0 */
1169 if (cmd_buffer == NULL)
1170 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1171 "malloc() failed for SMTP command buffer");
1173 /* For batched input, the protocol setting can be overridden from the
1174 command line by a trusted caller. */
1176 if (smtp_batched_input)
1178 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1181 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1182 reset later if any of EHLO/AUTH/STARTTLS are received. */
1186 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1188 /* Set up the buffer for inputting using direct read() calls, and arrange to
1189 call the local functions instead of the standard C ones. */
1191 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1192 if (smtp_inbuffer == NULL)
1193 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1194 receive_getc = smtp_getc;
1195 receive_ungetc = smtp_ungetc;
1196 receive_feof = smtp_feof;
1197 receive_ferror = smtp_ferror;
1198 smtp_inptr = smtp_inend = smtp_inbuffer;
1199 smtp_had_eof = smtp_had_error = 0;
1201 /* Set up the message size limit; this may be host-specific */
1203 thismessage_size_limit = expand_string_integer(message_size_limit);
1204 if (thismessage_size_limit < 0)
1206 if (thismessage_size_limit == -1)
1207 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1208 "%s", expand_string_message);
1210 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1211 "%s", expand_string_message);
1212 smtp_closedown(US"Temporary local problem - please try later");
1216 /* When a message is input locally via the -bs or -bS options, sender_host_
1217 unknown is set unless -oMa was used to force an IP address, in which case it
1218 is checked like a real remote connection. When -bs is used from inetd, this
1219 flag is not set, causing the sending host to be checked. The code that deals
1220 with IP source routing (if configured) is never required for -bs or -bS and
1221 the flag sender_host_notsocket is used to suppress it.
1223 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1224 reserve for certain hosts and/or networks. */
1226 if (!sender_host_unknown)
1229 BOOL reserved_host = FALSE;
1231 /* Look up IP options (source routing info) on the socket if this is not an
1232 -oMa "host", and if any are found, log them and drop the connection.
1234 Linux (and others now, see below) is different to everyone else, so there
1235 has to be some conditional compilation here. Versions of Linux before 2.1.15
1236 used a structure whose name was "options". Somebody finally realized that
1237 this name was silly, and it got changed to "ip_options". I use the
1238 newer name here, but there is a fudge in the script that sets up os.h
1239 to define a macro in older Linux systems.
1241 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1242 glibc 2, which has chosen ip_opts for the structure name. This is now
1243 really a glibc thing rather than a Linux thing, so the condition name
1244 has been changed to reflect this. It is relevant also to GNU/Hurd.
1246 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1247 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1248 a special macro defined in the os.h file.
1250 Some DGUX versions on older hardware appear not to support IP options at
1251 all, so there is now a general macro which can be set to cut out this
1254 How to do this properly in IPv6 is not yet known. */
1256 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1258 #ifdef GLIBC_IP_OPTIONS
1259 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1264 #elif defined DARWIN_IP_OPTIONS
1270 if (!host_checking && !sender_host_notsocket)
1273 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1274 struct ip_options *ipopt = store_get(optlen);
1276 struct ip_opts ipoptblock;
1277 struct ip_opts *ipopt = &ipoptblock;
1278 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1280 struct ipoption ipoptblock;
1281 struct ipoption *ipopt = &ipoptblock;
1282 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1285 /* Occasional genuine failures of getsockopt() have been seen - for
1286 example, "reset by peer". Therefore, just log and give up on this
1287 call, unless the error is ENOPROTOOPT. This error is given by systems
1288 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1289 of writing. So for that error, carry on - we just can't do an IP options
1292 DEBUG(D_receive) debug_printf("checking for IP options\n");
1294 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1297 if (errno != ENOPROTOOPT)
1299 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1300 host_and_ident(FALSE), strerror(errno));
1301 smtp_printf("451 SMTP service not available\r\n");
1306 /* Deal with any IP options that are set. On the systems I have looked at,
1307 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1308 more logging data than will fit in big_buffer. Nevertheless, after somebody
1309 questioned this code, I've added in some paranoid checking. */
1311 else if (optlen > 0)
1313 uschar *p = big_buffer;
1314 uschar *pend = big_buffer + big_buffer_size;
1315 uschar *opt, *adptr;
1317 struct in_addr addr;
1320 uschar *optstart = (uschar *)(ipopt->__data);
1322 uschar *optstart = (uschar *)(ipopt->ip_opts);
1324 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1327 DEBUG(D_receive) debug_printf("IP options exist\n");
1329 Ustrcpy(p, "IP options on incoming call:");
1332 for (opt = optstart; opt != NULL &&
1333 opt < (uschar *)(ipopt) + optlen;)
1347 if (!string_format(p, pend-p, " %s [@%s",
1348 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1350 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1352 inet_ntoa(ipopt->ip_dst)))
1354 inet_ntoa(ipopt->ipopt_dst)))
1362 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1364 while (optcount-- > 0)
1366 memcpy(&addr, adptr, sizeof(addr));
1367 if (!string_format(p, pend - p - 1, "%s%s",
1368 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1374 adptr += sizeof(struct in_addr);
1383 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1386 for (i = 0; i < opt[1]; i++)
1388 sprintf(CS p, "%2.2x ", opt[i]);
1399 log_write(0, LOG_MAIN, "%s", big_buffer);
1401 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1403 log_write(0, LOG_MAIN|LOG_REJECT,
1404 "connection from %s refused (IP options)", host_and_ident(FALSE));
1406 smtp_printf("554 SMTP service not available\r\n");
1410 /* Length of options = 0 => there are no options */
1412 else DEBUG(D_receive) debug_printf("no IP options found\n");
1414 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1416 /* Set keep-alive in socket options. The option is on by default. This
1417 setting is an attempt to get rid of some hanging connections that stick in
1418 read() when the remote end (usually a dialup) goes away. */
1420 if (smtp_accept_keepalive && !sender_host_notsocket)
1421 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1423 /* If the current host matches host_lookup, set the name by doing a
1424 reverse lookup. On failure, sender_host_name will be NULL and
1425 host_lookup_failed will be TRUE. This may or may not be serious - optional
1428 if (verify_check_host(&host_lookup) == OK)
1430 (void)host_name_lookup();
1431 host_build_sender_fullhost();
1434 /* Delay this until we have the full name, if it is looked up. */
1436 set_process_info("handling incoming connection from %s",
1437 host_and_ident(FALSE));
1439 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1440 smtps port for use with older style SSL MTAs. */
1443 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1447 /* Test for explicit connection rejection */
1449 if (verify_check_host(&host_reject_connection) == OK)
1451 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1452 "from %s (host_reject_connection)", host_and_ident(FALSE));
1453 smtp_printf("554 SMTP service not available\r\n");
1457 /* Test with TCP Wrappers if so configured */
1459 #ifdef USE_TCP_WRAPPERS
1460 if (!hosts_ctl("exim",
1461 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1462 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1463 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1465 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1466 log_write(L_connection_reject,
1467 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1468 "(tcp wrappers)", host_and_ident(FALSE));
1469 smtp_printf("554 SMTP service not available\r\n");
1474 /* Check for reserved slots. Note that the count value doesn't include
1475 this process, as it gets upped in the parent process. */
1477 if (smtp_accept_max > 0 &&
1478 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1480 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1482 log_write(L_connection_reject,
1483 LOG_MAIN, "temporarily refused connection from %s: not in "
1484 "reserve list: connected=%d max=%d reserve=%d%s",
1485 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1486 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1487 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1488 "please try again later\r\n", smtp_active_hostname);
1491 reserved_host = TRUE;
1494 /* If a load level above which only messages from reserved hosts are
1495 accepted is set, check the load. For incoming calls via the daemon, the
1496 check is done in the superior process if there are no reserved hosts, to
1497 save a fork. In all cases, the load average will already be available
1498 in a global variable at this point. */
1500 if (smtp_load_reserve >= 0 &&
1501 load_average > smtp_load_reserve &&
1503 verify_check_host(&smtp_reserve_hosts) != OK)
1505 log_write(L_connection_reject,
1506 LOG_MAIN, "temporarily refused connection from %s: not in "
1507 "reserve list and load average = %.2f", host_and_ident(FALSE),
1508 (double)load_average/1000.0);
1509 smtp_printf("421 %s: Too much load; please try again later\r\n",
1510 smtp_active_hostname);
1514 /* Determine whether unqualified senders or recipients are permitted
1515 for this host. Unfortunately, we have to do this every time, in order to
1516 set the flags so that they can be inspected when considering qualifying
1517 addresses in the headers. For a site that permits no qualification, this
1518 won't take long, however. */
1520 allow_unqualified_sender =
1521 verify_check_host(&sender_unqualified_hosts) == OK;
1523 allow_unqualified_recipient =
1524 verify_check_host(&recipient_unqualified_hosts) == OK;
1526 /* Determine whether HELO/EHLO is required for this host. The requirement
1527 can be hard or soft. */
1529 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1531 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1533 /* Determine whether this hosts is permitted to send syntactic junk
1534 after a HELO or EHLO command. */
1536 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1539 /* For batch SMTP input we are now done. */
1541 if (smtp_batched_input) return TRUE;
1543 /* Run the ACL if it exists */
1545 if (acl_smtp_connect != NULL)
1548 uschar *user_msg, *log_msg;
1549 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(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), 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_command_argument == NULL)?
1825 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
1826 string_sprintf("%s %s", acl_wherenames[where], smtp_command_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_command_argument;
2195 while ((c = *smtp_command_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_command_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_command_argument != 0)
2211 *smtp_command_argument++ = 0;
2212 while (isspace(*smtp_command_argument)) smtp_command_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
2232 line as data. Initialize $0 empty. The authenticator may set up
2233 other numeric variables. Afterwards, have a go at expanding the set_id
2234 string, even if authentication failed - for bad passwords it can be useful
2235 to log the userid. On success, require set_id to expand and exist, and
2236 put it in authenticated_id. Save this in permanent store, as the working
2237 store gets reset at HELO, RSET, etc. */
2240 expand_nlength[0] = 0; /* $0 contains nothing */
2242 c = (au->info->servercode)(au, smtp_command_argument);
2243 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2244 expand_nmax = -1; /* Reset numeric variables */
2246 /* The value of authenticated_id is stored in the spool file and printed in
2247 log lines. It must not contain binary zeros or newline characters. In
2248 normal use, it never will, but when playing around or testing, this error
2249 can (did) happen. To guard against this, ensure that the id contains only
2250 printing characters. */
2252 if (set_id != NULL) set_id = string_printing(set_id);
2254 /* For the non-OK cases, set up additional logging data if set_id
2259 if (set_id != NULL && *set_id != 0)
2260 set_id = string_sprintf(" (set_id=%s)", set_id);
2264 /* Switch on the result */
2269 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2271 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2272 sender_host_authenticated = au->name;
2273 authentication_failed = FALSE;
2275 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2276 ((sender_host_address != NULL)? pnlocal : 0);
2277 s = ss = US"235 Authentication succeeded";
2278 authenticated_by = au;
2282 /* Authentication succeeded, but we failed to expand the set_id string.
2283 Treat this as a temporary error. */
2285 auth_defer_msg = expand_string_message;
2289 s = string_sprintf("435 Unable to authenticate at present%s",
2290 auth_defer_user_msg);
2291 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2292 set_id, auth_defer_msg);
2296 s = ss = US"501 Invalid base64 data";
2300 s = ss = US"501 Authentication cancelled";
2304 s = ss = US"553 Initial data not expected";
2308 s = US"535 Incorrect authentication data";
2309 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2313 s = US"435 Internal error";
2314 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2315 "check", set_id, c);
2319 smtp_printf("%s\r\n", s);
2321 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2322 au->name, host_and_ident(FALSE), ss);
2324 break; /* AUTH_CMD */
2326 /* The HELO/EHLO commands are permitted to appear in the middle of a
2327 session as well as at the beginning. They have the effect of a reset in
2328 addition to their other functions. Their absence at the start cannot be
2329 taken to be an error.
2333 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2334 or 502 failure replies MUST be returned as appropriate. The SMTP
2335 server MUST stay in the same state after transmitting these replies
2336 that it was in before the EHLO was received.
2338 Therefore, we do not do the reset until after checking the command for
2339 acceptability. This change was made for Exim release 4.11. Previously
2340 it did the reset first. */
2351 HELO_EHLO: /* Common code for HELO and EHLO */
2352 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2353 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2355 /* Reject the HELO if its argument was invalid or non-existent. A
2356 successful check causes the argument to be saved in malloc store. */
2358 if (!check_helo(smtp_command_argument))
2360 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2362 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2363 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2364 (*smtp_command_argument == 0)? US"(no argument given)" :
2365 string_printing(smtp_command_argument));
2367 if (++synprot_error_count > smtp_max_synprot_errors)
2369 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2370 "syntax or protocol errors (last command was \"%s\")",
2371 host_and_ident(FALSE), cmd_buffer);
2378 /* If sender_host_unknown is true, we have got here via the -bs interface,
2379 not called from inetd. Otherwise, we are running an IP connection and the
2380 host address will be set. If the helo name is the primary name of this
2381 host and we haven't done a reverse lookup, force one now. If helo_required
2382 is set, ensure that the HELO name matches the actual host. If helo_verify
2383 is set, do the same check, but softly. */
2385 if (!sender_host_unknown)
2387 BOOL old_helo_verified = helo_verified;
2388 uschar *p = smtp_command_argument;
2390 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2393 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2394 because otherwise the log can be confusing. */
2396 if (sender_host_name == NULL &&
2397 (deliver_domain = sender_helo_name, /* set $domain */
2398 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2399 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2400 (void)host_name_lookup();
2402 /* Rebuild the fullhost info to include the HELO name (and the real name
2403 if it was looked up.) */
2405 host_build_sender_fullhost(); /* Rebuild */
2406 set_process_info("handling%s incoming connection from %s",
2407 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2409 /* Verify if configured. This doesn't give much security, but it does
2410 make some people happy to be able to do it. If helo_required is set,
2411 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2412 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2413 now obsolescent, since the verification can now be requested selectively
2416 helo_verified = helo_verify_failed = FALSE;
2417 if (helo_required || helo_verify)
2419 BOOL tempfail = !smtp_verify_helo();
2424 smtp_printf("%d %s argument does not match calling host\r\n",
2425 tempfail? 451 : 550, hello);
2426 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2427 tempfail? "temporarily " : "",
2428 hello, sender_helo_name, host_and_ident(FALSE));
2429 helo_verified = old_helo_verified;
2430 break; /* End of HELO/EHLO processing */
2432 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2433 "helo_try_verify_hosts\n", hello);
2438 #ifdef EXPERIMENTAL_SPF
2439 /* set up SPF context */
2440 spf_init(sender_helo_name, sender_host_address);
2443 /* Apply an ACL check if one is defined */
2445 if (acl_smtp_helo != NULL)
2447 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2450 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2451 sender_helo_name = NULL;
2452 host_build_sender_fullhost(); /* Rebuild */
2457 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2458 abandoning any previous message. */
2460 received_protocol = (esmtp?
2462 ((sender_host_authenticated != NULL)? pauthed : 0) +
2463 ((tls_active >= 0)? pcrpted : 0)]
2465 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2467 ((sender_host_address != NULL)? pnlocal : 0);
2469 smtp_reset(reset_point);
2472 /* Generate an OK reply, including the ident if present, and also
2473 the IP address if present. Reflecting back the ident is intended
2474 as a deterrent to mail forgers. For maximum efficiency, and also
2475 because some broken systems expect each response to be in a single
2476 packet, arrange that it is sent in one write(). */
2478 auth_advertised = FALSE;
2479 pipelining_advertised = FALSE;
2481 tls_advertised = FALSE;
2484 s = string_sprintf("250 %s Hello %s%s%s",
2485 smtp_active_hostname,
2486 (sender_ident == NULL)? US"" : sender_ident,
2487 (sender_ident == NULL)? US"" : US" at ",
2488 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2493 if (sender_host_address != NULL)
2495 s = string_cat(s, &size, &ptr, US" [", 2);
2496 s = string_cat(s, &size, &ptr, sender_host_address,
2497 Ustrlen(sender_host_address));
2498 s = string_cat(s, &size, &ptr, US"]", 1);
2501 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2503 /* If we received EHLO, we must create a multiline response which includes
2504 the functions supported. */
2510 /* I'm not entirely happy with this, as an MTA is supposed to check
2511 that it has enough room to accept a message of maximum size before
2512 it sends this. However, there seems little point in not sending it.
2513 The actual size check happens later at MAIL FROM time. By postponing it
2514 till then, VRFY and EXPN can be used after EHLO when space is short. */
2516 if (thismessage_size_limit > 0)
2518 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2519 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2523 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2526 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2527 clean; if it has an 8-bit character in its hand, it just sends it. It
2528 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2529 However, some users want this option simply in order to stop MUAs
2530 mangling messages that contain top-bit-set characters. It is therefore
2531 provided as an option. */
2533 if (accept_8bitmime)
2534 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2536 /* Advertise ETRN if there's an ACL checking whether a host is
2537 permitted to issue it; a check is made when any host actually tries. */
2539 if (acl_smtp_etrn != NULL)
2541 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2544 /* Advertise EXPN if there's an ACL checking whether a host is
2545 permitted to issue it; a check is made when any host actually tries. */
2547 if (acl_smtp_expn != NULL)
2549 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2552 /* Exim is quite happy with pipelining, so let the other end know that
2553 it is safe to use it, unless advertising is disabled. */
2555 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2557 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2558 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2559 pipelining_advertised = TRUE;
2562 /* If any server authentication mechanisms are configured, advertise
2563 them if the current host is in auth_advertise_hosts. The problem with
2564 advertising always is that some clients then require users to
2565 authenticate (and aren't configurable otherwise) even though it may not
2566 be necessary (e.g. if the host is in host_accept_relay).
2568 RFC 2222 states that SASL mechanism names contain only upper case
2569 letters, so output the names in upper case, though we actually recognize
2570 them in either case in the AUTH command. */
2574 if (verify_check_host(&auth_advertise_hosts) == OK)
2578 for (au = auths; au != NULL; au = au->next)
2580 if (au->server && (au->advertise_condition == NULL ||
2581 expand_check_condition(au->advertise_condition, au->name,
2582 US"authenticator")))
2587 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2589 auth_advertised = TRUE;
2592 s = string_cat(s, &size, &ptr, US" ", 1);
2593 s = string_cat(s, &size, &ptr, au->public_name,
2594 Ustrlen(au->public_name));
2595 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2596 au->advertised = TRUE;
2598 else au->advertised = FALSE;
2600 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2604 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2605 if it has been included in the binary, and the host matches
2606 tls_advertise_hosts. We must *not* advertise if we are already in a
2607 secure connection. */
2610 if (tls_active < 0 &&
2611 verify_check_host(&tls_advertise_hosts) != FAIL)
2613 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2614 tls_advertised = TRUE;
2618 /* Finish off the multiline reply with one that is always available. */
2620 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2623 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2629 if (tls_active >= 0) (void)tls_write(s, ptr); else
2632 (void)fwrite(s, 1, ptr, smtp_out);
2633 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2635 break; /* HELO/EHLO */
2638 /* The MAIL command requires an address as an operand. All we do
2639 here is to parse it for syntactic correctness. The form "<>" is
2640 a special case which converts into an empty string. The start/end
2641 pointers in the original are not used further for this address, as
2642 it is the canonical extracted address which is all that is kept. */
2645 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2646 was_rej_mail = TRUE; /* Reset if accepted */
2648 if (helo_required && !helo_seen)
2650 smtp_printf("503 HELO or EHLO required\r\n");
2651 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2652 "HELO/EHLO given", host_and_ident(FALSE));
2656 if (sender_address != NULL)
2658 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2659 US"sender already given");
2663 if (smtp_command_argument[0] == 0)
2665 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2666 US"MAIL must have an address operand");
2670 /* Check to see if the limit for messages per connection would be
2671 exceeded by accepting further messages. */
2673 if (smtp_accept_max_per_connection > 0 &&
2674 smtp_mailcmd_count > smtp_accept_max_per_connection)
2676 smtp_printf("421 too many messages in this connection\r\n");
2677 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2678 "messages in one connection", host_and_ident(TRUE));
2682 /* Reset for start of message - even if this is going to fail, we
2683 obviously need to throw away any previous data. */
2685 smtp_reset(reset_point);
2687 sender_data = recipient_data = NULL;
2689 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2693 uschar *name, *value, *end;
2694 unsigned long int size;
2696 if (!extract_option(&name, &value)) break;
2698 /* Handle SIZE= by reading the value. We don't do the check till later,
2699 in order to be able to log the sender address on failure. */
2701 if (strcmpic(name, US"SIZE") == 0 &&
2702 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2704 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2706 message_size = (int)size;
2709 /* If this session was initiated with EHLO and accept_8bitmime is set,
2710 Exim will have indicated that it supports the BODY=8BITMIME option. In
2711 fact, it does not support this according to the RFCs, in that it does not
2712 take any special action for forwarding messages containing 8-bit
2713 characters. That is why accept_8bitmime is not the default setting, but
2714 some sites want the action that is provided. We recognize both "8BITMIME"
2715 and "7BIT" as body types, but take no action. */
2717 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2718 (strcmpic(value, US"8BITMIME") == 0 ||
2719 strcmpic(value, US"7BIT") == 0)) {}
2721 /* Handle the AUTH extension. If the value given is not "<>" and either
2722 the ACL says "yes" or there is no ACL but the sending host is
2723 authenticated, we set it up as the authenticated sender. However, if the
2724 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2725 the condition is met. The value of AUTH is an xtext, which means that +,
2726 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2729 else if (strcmpic(name, US"AUTH") == 0)
2731 if (Ustrcmp(value, "<>") != 0)
2736 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2738 /* Put back terminator overrides for error message */
2741 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2742 US"invalid data for AUTH");
2746 if (acl_smtp_mailauth == NULL)
2748 ignore_msg = US"client not authenticated";
2749 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2753 ignore_msg = US"rejected by ACL";
2754 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2755 &user_msg, &log_msg);
2761 if (authenticated_by == NULL ||
2762 authenticated_by->mail_auth_condition == NULL ||
2763 expand_check_condition(authenticated_by->mail_auth_condition,
2764 authenticated_by->name, US"authenticator"))
2765 break; /* Accept the AUTH */
2767 ignore_msg = US"server_mail_auth_condition failed";
2768 if (authenticated_id != NULL)
2769 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2770 ignore_msg, authenticated_id);
2775 authenticated_sender = NULL;
2776 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2777 value, host_and_ident(TRUE), ignore_msg);
2780 /* Should only get DEFER or ERROR here. Put back terminator
2781 overrides for error message */
2786 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2793 /* Unknown option. Stick back the terminator characters and break
2794 the loop. An error for a malformed address will occur. */
2804 /* If we have passed the threshold for rate limiting, apply the current
2805 delay, and update it for next time, provided this is a limited host. */
2807 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2808 verify_check_host(&smtp_ratelimit_hosts) == OK)
2810 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2811 smtp_delay_mail/1000.0);
2812 millisleep((int)smtp_delay_mail);
2813 smtp_delay_mail *= smtp_rlm_factor;
2814 if (smtp_delay_mail > (double)smtp_rlm_limit)
2815 smtp_delay_mail = (double)smtp_rlm_limit;
2818 /* Now extract the address, first applying any SMTP-time rewriting. The
2819 TRUE flag allows "<>" as a sender address. */
2821 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2822 rewrite_one(smtp_command_argument, rewrite_smtp, NULL, FALSE, US"",
2823 global_rewrite_rules) : smtp_command_argument;
2825 /* rfc821_domains = TRUE; << no longer needed */
2827 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2829 /* rfc821_domains = FALSE; << no longer needed */
2831 if (raw_sender == NULL)
2833 done = synprot_error(L_smtp_syntax_error, 501, smtp_command_argument, errmess);
2837 sender_address = raw_sender;
2839 /* If there is a configured size limit for mail, check that this message
2840 doesn't exceed it. The check is postponed to this point so that the sender
2843 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2845 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2846 log_write(L_size_reject,
2847 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2848 "message too big: size%s=%d max=%d",
2850 host_and_ident(TRUE),
2851 (message_size == INT_MAX)? ">" : "",
2853 thismessage_size_limit);
2854 sender_address = NULL;
2858 /* Check there is enough space on the disk unless configured not to.
2859 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2860 plus the current message - i.e. we accept the message only if it won't
2861 reduce the space below the threshold. Add 5000 to the size to allow for
2862 overheads such as the Received: line and storing of recipients, etc.
2863 By putting the check here, even when SIZE is not given, it allow VRFY
2864 and EXPN etc. to be used when space is short. */
2866 if (!receive_check_fs(
2867 (smtp_check_spool_space && message_size >= 0)?
2868 message_size + 5000 : 0))
2870 smtp_printf("452 Space shortage, please try later\r\n");
2871 sender_address = NULL;
2875 /* If sender_address is unqualified, reject it, unless this is a locally
2876 generated message, or the sending host or net is permitted to send
2877 unqualified addresses - typically local machines behaving as MUAs -
2878 in which case just qualify the address. The flag is set above at the start
2879 of the SMTP connection. */
2881 if (sender_domain == 0 && sender_address[0] != 0)
2883 if (allow_unqualified_sender)
2885 sender_domain = Ustrlen(sender_address) + 1;
2886 sender_address = rewrite_address_qualify(sender_address, FALSE);
2887 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2892 smtp_printf("501 %s: sender address must contain a domain\r\n",
2893 smtp_command_argument);
2894 log_write(L_smtp_syntax_error,
2895 LOG_MAIN|LOG_REJECT,
2896 "unqualified sender rejected: <%s> %s%s",
2898 host_and_ident(TRUE),
2900 sender_address = NULL;
2905 /* Apply an ACL check if one is defined, before responding */
2907 rc = (acl_smtp_mail == NULL)? OK :
2908 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2910 if (rc == OK || rc == DISCARD)
2912 smtp_printf("250 OK\r\n");
2913 smtp_delay_rcpt = smtp_rlr_base;
2914 recipients_discarded = (rc == DISCARD);
2915 was_rej_mail = FALSE;
2920 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2921 sender_address = NULL;
2926 /* The RCPT command requires an address as an operand. All we do
2927 here is to parse it for syntactic correctness. There may be any number
2928 of RCPT commands, specifying multiple senders. We build them all into
2929 a data structure that is in argc/argv format. The start/end values
2930 given by parse_extract_address are not used, as we keep only the
2931 extracted address. */
2937 /* There must be a sender address; if the sender was rejected and
2938 pipelining was advertised, we assume the client was pipelining, and do not
2939 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2940 get the same treatment. */
2942 if (sender_address == NULL)
2944 if (pipelining_advertised && last_was_rej_mail)
2946 smtp_printf("503 sender not yet given\r\n");
2947 was_rej_mail = TRUE;
2951 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2952 US"sender not yet given");
2953 was_rcpt = FALSE; /* Not a valid RCPT */
2959 /* Check for an operand */
2961 if (smtp_command_argument[0] == 0)
2963 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2964 US"RCPT must have an address operand");
2969 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2970 as a recipient address */
2972 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2973 rewrite_one(smtp_command_argument, rewrite_smtp, NULL, FALSE, US"",
2974 global_rewrite_rules) : smtp_command_argument;
2976 /* rfc821_domains = TRUE; << no longer needed */
2977 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2978 &recipient_domain, FALSE);
2979 /* rfc821_domains = FALSE; << no longer needed */
2981 if (recipient == NULL)
2983 done = synprot_error(L_smtp_syntax_error, 501, smtp_command_argument, errmess);
2988 /* If the recipient address is unqualified, reject it, unless this is a
2989 locally generated message. However, unqualified addresses are permitted
2990 from a configured list of hosts and nets - typically when behaving as
2991 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2992 really. The flag is set at the start of the SMTP connection.
2994 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2995 assumed this meant "reserved local part", but the revision of RFC 821 and
2996 friends now makes it absolutely clear that it means *mailbox*. Consequently
2997 we must always qualify this address, regardless. */
2999 if (recipient_domain == 0)
3001 if (allow_unqualified_recipient ||
3002 strcmpic(recipient, US"postmaster") == 0)
3004 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3006 recipient_domain = Ustrlen(recipient) + 1;
3007 recipient = rewrite_address_qualify(recipient, TRUE);
3012 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3013 smtp_command_argument);
3014 log_write(L_smtp_syntax_error,
3015 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3016 "<%s> %s%s", recipient, host_and_ident(TRUE),
3022 /* Check maximum allowed */
3024 if (rcpt_count > recipients_max && recipients_max > 0)
3026 if (recipients_max_reject)
3029 smtp_printf("552 too many recipients\r\n");
3031 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3032 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3037 smtp_printf("452 too many recipients\r\n");
3039 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3040 "temporarily rejected: sender=<%s> %s", sender_address,
3041 host_and_ident(TRUE));
3048 /* If we have passed the threshold for rate limiting, apply the current
3049 delay, and update it for next time, provided this is a limited host. */
3051 if (rcpt_count > smtp_rlr_threshold &&
3052 verify_check_host(&smtp_ratelimit_hosts) == OK)
3054 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3055 smtp_delay_rcpt/1000.0);
3056 millisleep((int)smtp_delay_rcpt);
3057 smtp_delay_rcpt *= smtp_rlr_factor;
3058 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3059 smtp_delay_rcpt = (double)smtp_rlr_limit;
3062 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3063 for them. Otherwise, check the access control list for this recipient. */
3065 rc = recipients_discarded? DISCARD :
3066 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3068 /* The ACL was happy */
3072 smtp_printf("250 Accepted\r\n");
3073 receive_add_recipient(recipient, -1);
3076 /* The recipient was discarded */
3078 else if (rc == DISCARD)
3080 smtp_printf("250 Accepted\r\n");
3083 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3084 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3085 (sender_address_unrewritten != NULL)?
3086 sender_address_unrewritten : sender_address,
3087 smtp_command_argument, recipients_discarded? "MAIL" : "RCPT",
3088 (log_msg == NULL)? US"" : US": ",
3089 (log_msg == NULL)? US"" : log_msg);
3092 /* Either the ACL failed the address, or it was deferred. */
3096 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3097 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3102 /* The DATA command is legal only if it follows successful MAIL FROM
3103 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3104 not counted as a protocol error if it follows RCPT (which must have been
3105 rejected if there are no recipients.) This function is complete when a
3106 valid DATA command is encountered.
3108 Note concerning the code used: RFC 2821 says this:
3110 - If there was no MAIL, or no RCPT, command, or all such commands
3111 were rejected, the server MAY return a "command out of sequence"
3112 (503) or "no valid recipients" (554) reply in response to the
3115 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3116 because it is the same whether pipelining is in use or not. */
3119 if (!discarded && recipients_count <= 0)
3121 if (pipelining_advertised && last_was_rcpt)
3122 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3124 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3125 US"valid RCPT command must precede DATA");
3129 if (toomany && recipients_max_reject)
3131 sender_address = NULL; /* This will allow a new MAIL without RSET */
3132 sender_address_unrewritten = NULL;
3133 smtp_printf("554 Too many recipients\r\n");
3137 if (acl_smtp_predata == NULL) rc = OK; else
3139 enable_dollar_recipients = TRUE;
3140 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3142 enable_dollar_recipients = FALSE;
3147 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3149 message_ended = END_NOTENDED; /* Indicate in middle of data */
3152 /* Either the ACL failed the address, or it was deferred. */
3155 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3161 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3163 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3169 /* rfc821_domains = TRUE; << no longer needed */
3170 address = parse_extract_address(smtp_command_argument, &errmess, &start, &end,
3171 &recipient_domain, FALSE);
3172 /* rfc821_domains = FALSE; << no longer needed */
3174 if (address == NULL)
3175 s = string_sprintf("501 %s", errmess);
3178 address_item *addr = deliver_make_addr(address, FALSE);
3179 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3180 -1, -1, NULL, NULL, NULL))
3183 s = string_sprintf("250 <%s> is deliverable", address);
3187 s = (addr->message != NULL)?
3188 string_sprintf("451 <%s> %s", address, addr->message) :
3189 string_sprintf("451 Cannot resolve <%s> at this time", address);
3193 s = (addr->message != NULL)?
3194 string_sprintf("550 <%s> %s", address, addr->message) :
3195 string_sprintf("550 <%s> is not deliverable", address);
3196 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3197 smtp_command_argument, host_and_ident(TRUE));
3202 smtp_printf("%s\r\n", s);
3208 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3210 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3213 BOOL save_log_testing_mode = log_testing_mode;
3214 address_test_mode = log_testing_mode = TRUE;
3215 (void) verify_address(deliver_make_addr(smtp_command_argument, FALSE),
3216 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3218 address_test_mode = FALSE;
3219 log_testing_mode = save_log_testing_mode; /* true for -bh */
3227 if (!tls_advertised)
3229 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3230 US"STARTTLS command used when not advertised");
3234 /* Apply an ACL check if one is defined */
3236 if (acl_smtp_starttls != NULL)
3238 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3242 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3247 /* RFC 2487 is not clear on when this command may be sent, though it
3248 does state that all information previously obtained from the client
3249 must be discarded if a TLS session is started. It seems reasonble to
3250 do an implied RSET when STARTTLS is received. */
3252 incomplete_transaction_log(US"STARTTLS");
3253 smtp_reset(reset_point);
3255 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3257 /* Attempt to start up a TLS session, and if successful, discard all
3258 knowledge that was obtained previously. At least, that's what the RFC says,
3259 and that's what happens by default. However, in order to work round YAEB,
3260 there is an option to remember the esmtp state. Sigh.
3262 We must allow for an extra EHLO command and an extra AUTH command after
3263 STARTTLS that don't add to the nonmail command count. */
3265 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3267 if (!tls_remember_esmtp)
3268 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3269 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3270 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3271 if (sender_helo_name != NULL)
3273 store_free(sender_helo_name);
3274 sender_helo_name = NULL;
3275 host_build_sender_fullhost(); /* Rebuild */
3276 set_process_info("handling incoming TLS connection from %s",
3277 host_and_ident(FALSE));
3279 received_protocol = (esmtp?
3280 protocols[pextend + pcrpted +
3281 ((sender_host_authenticated != NULL)? pauthed : 0)]
3283 protocols[pnormal + pcrpted])
3285 ((sender_host_address != NULL)? pnlocal : 0);
3287 sender_host_authenticated = NULL;
3288 authenticated_id = NULL;
3289 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3290 DEBUG(D_tls) debug_printf("TLS active\n");
3291 break; /* Successful STARTTLS */
3294 /* Some local configuration problem was discovered before actually trying
3295 to do a TLS handshake; give a temporary error. */
3297 else if (rc == DEFER)
3299 smtp_printf("454 TLS currently unavailable\r\n");
3303 /* Hard failure. Reject everything except QUIT or closed connection. One
3304 cause for failure is a nested STARTTLS, in which case tls_active remains
3305 set, but we must still reject all incoming commands. */
3307 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3310 switch(smtp_read_command(FALSE))
3313 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3314 smtp_get_connection_info());
3319 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3320 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3321 smtp_get_connection_info());
3326 smtp_printf("554 Security failure\r\n");
3335 /* The ACL for QUIT is provided for gathering statistical information or
3336 similar; it does not affect the response code, but it can supply a custom
3340 incomplete_transaction_log(US"QUIT");
3342 if (acl_smtp_quit != NULL)
3344 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit,&user_msg,&log_msg);
3346 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3349 else user_msg = NULL;
3351 if (user_msg == NULL)
3352 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3354 smtp_printf("221 %s\r\n", user_msg);
3361 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3362 smtp_get_connection_info());
3367 incomplete_transaction_log(US"RSET");
3368 smtp_reset(reset_point);
3370 smtp_printf("250 Reset OK\r\n");
3371 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3376 smtp_printf("250 OK\r\n");
3380 /* Show ETRN/EXPN/VRFY if there's
3381 an ACL for checking hosts; if actually used, a check will be done for
3385 smtp_printf("214-Commands supported:\r\n");
3389 Ustrcat(buffer, " AUTH");
3391 Ustrcat(buffer, " STARTTLS");
3393 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3394 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3395 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3396 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3397 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3398 smtp_printf("214%s\r\n", buffer);
3404 incomplete_transaction_log(US"connection lost");
3405 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3407 /* Don't log by default unless in the middle of a message, as some mailers
3408 just drop the call rather than sending QUIT, and it clutters up the logs.
3411 if (sender_address != NULL || recipients_count > 0)
3412 log_write(L_lost_incoming_connection,
3414 "unexpected %s while reading SMTP command from %s%s",
3415 sender_host_unknown? "EOF" : "disconnection",
3416 host_and_ident(FALSE), smtp_read_error);
3418 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3419 smtp_get_connection_info(), smtp_read_error);
3426 if (sender_address != NULL)
3428 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3429 US"ETRN is not permitted inside a transaction");
3433 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_command_argument,
3434 host_and_ident(FALSE));
3436 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
3439 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3443 /* Compute the serialization key for this command. */
3445 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_command_argument);
3447 /* If a command has been specified for running as a result of ETRN, we
3448 permit any argument to ETRN. If not, only the # standard form is permitted,
3449 since that is strictly the only kind of ETRN that can be implemented
3450 according to the RFC. */
3452 if (smtp_etrn_command != NULL)
3456 etrn_command = smtp_etrn_command;
3457 deliver_domain = smtp_command_argument;
3458 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3459 US"ETRN processing", &error);
3460 deliver_domain = NULL;
3463 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3465 smtp_printf("458 Internal failure\r\n");
3470 /* Else set up to call Exim with the -R option. */
3474 if (*smtp_command_argument++ != '#')
3476 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3477 US"argument must begin with #");
3480 etrn_command = US"exim -R";
3481 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3482 smtp_command_argument);
3485 /* If we are host-testing, don't actually do anything. */
3491 debug_printf("ETRN command is: %s\n", etrn_command);
3492 debug_printf("ETRN command execution skipped\n");
3494 smtp_printf("250 OK\r\n");
3499 /* If ETRN queue runs are to be serialized, check the database to
3500 ensure one isn't already running. */
3502 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3504 smtp_printf("458 Already processing %s\r\n", smtp_command_argument);
3508 /* Fork a child process and run the command. We don't want to have to
3509 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3510 forking. It should be set that way anyway for external incoming SMTP,
3511 but we save and restore to be tidy. If serialization is required, we
3512 actually run the command in yet another process, so we can wait for it
3513 to complete and then remove the serialization lock. */
3515 oldsignal = signal(SIGCHLD, SIG_IGN);
3517 if ((pid = fork()) == 0)
3519 smtp_input = FALSE; /* This process is not associated with the */
3520 (void)fclose(smtp_in); /* SMTP call any more. */
3521 (void)fclose(smtp_out);
3523 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3525 /* If not serializing, do the exec right away. Otherwise, fork down
3526 into another process. */
3528 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3530 DEBUG(D_exec) debug_print_argv(argv);
3531 exim_nullstd(); /* Ensure std{in,out,err} exist */
3532 execv(CS argv[0], (char *const *)argv);
3533 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3534 etrn_command, strerror(errno));
3535 _exit(EXIT_FAILURE); /* paranoia */
3538 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3539 is, we are in the first subprocess, after forking again. All we can do
3540 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3541 complete, before removing the serialization. */
3544 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3545 "failed: %s", strerror(errno));
3549 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3551 (void)wait(&status);
3552 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3556 enq_end(etrn_serialize_key);
3557 _exit(EXIT_SUCCESS);
3560 /* Back in the top level SMTP process. Check that we started a subprocess
3561 and restore the signal state. */
3565 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3567 smtp_printf("458 Unable to fork process\r\n");
3568 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3570 else smtp_printf("250 OK\r\n");
3572 signal(SIGCHLD, oldsignal);
3577 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3578 US"unexpected argument data");
3582 /* This currently happens only for NULLs, but could be extended. */
3585 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3586 US"NULL character(s) present (shown as '?')");
3587 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3592 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3593 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3594 c = smtp_inend - smtp_inptr;
3595 if (c > 150) c = 150;
3597 incomplete_transaction_log(US"sync failure");
3598 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
3599 "(next input sent too soon: pipelining was%s advertised): "
3600 "rejected \"%s\" %s next input=\"%s\"",
3601 pipelining_advertised? "" : " not",
3602 cmd_buffer, host_and_ident(TRUE),
3603 string_printing(smtp_inptr));
3604 smtp_printf("554 SMTP synchronization error\r\n");
3605 done = 1; /* Pretend eof - drops connection */
3609 case TOO_MANY_NONMAIL_CMD:
3610 incomplete_transaction_log(US"too many non-mail commands");
3611 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3612 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
3613 smtp_command_argument - cmd_buffer, cmd_buffer);
3614 smtp_printf("554 Too many nonmail commands\r\n");
3615 done = 1; /* Pretend eof - drops connection */
3620 if (unknown_command_count++ >= smtp_max_unknown_commands)
3622 log_write(L_smtp_syntax_error, LOG_MAIN,
3623 "SMTP syntax error in \"%s\" %s %s",
3624 string_printing(cmd_buffer), host_and_ident(TRUE),
3625 US"unrecognized command");
3626 incomplete_transaction_log(US"unrecognized command");
3627 smtp_printf("500 Too many unrecognized commands\r\n");
3629 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3630 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3634 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3635 US"unrecognized command");
3639 /* This label is used by goto's inside loops that want to break out to
3640 the end of the command-processing loop. */
3643 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3644 last_was_rcpt = was_rcpt; /* protocol error handling */
3648 return done - 2; /* Convert yield values */
3651 /* End of smtp_in.c */