1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.37 2006/03/16 11:14:46 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2006 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. */
42 #define smtp_cmd_buffer_size 2048
44 /* Size of buffer for reading SMTP incoming packets */
46 #define in_buffer_size 8192
48 /* Structure for SMTP command list */
55 short int is_mail_cmd;
58 /* Codes for identifying commands. We order them so that those that come first
59 are those for which synchronization is always required. Checking this can help
63 /* These commands are required to be synchronized, i.e. to be the last in a
64 block of commands when pipelining. */
66 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
67 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
68 ETRN_CMD, /* This by analogy with TURN from the RFC */
69 STARTTLS_CMD, /* Required by the STARTTLS RFC */
71 /* This is a dummy to identify the non-sync commands when pipelining */
73 NON_SYNC_CMD_PIPELINING,
75 /* These commands need not be synchronized when pipelining */
77 MAIL_CMD, RCPT_CMD, RSET_CMD,
79 /* This is a dummy to identify the non-sync commands when not pipelining */
81 NON_SYNC_CMD_NON_PIPELINING,
83 /* I have been unable to find a statement about the use of pipelining
84 with AUTH, so to be on the safe side it is here, though I kind of feel
85 it should be up there with the synchronized commands. */
89 /* I'm not sure about these, but I don't think they matter. */
93 /* These are specials that don't correspond to actual commands */
95 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
96 TOO_MANY_NONMAIL_CMD };
100 /*************************************************
101 * Local static variables *
102 *************************************************/
104 static auth_instance *authenticated_by;
105 static BOOL auth_advertised;
107 static BOOL tls_advertised;
110 static BOOL helo_required = FALSE;
111 static BOOL helo_verify = FALSE;
112 static BOOL helo_seen;
113 static BOOL helo_accept_junk;
114 static BOOL count_nonmail;
115 static BOOL pipelining_advertised;
116 static int nonmail_command_count;
117 static int synprot_error_count;
118 static int unknown_command_count;
119 static int sync_cmd_limit;
120 static int smtp_write_error = 0;
122 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
123 final fields of all except AUTH are forced TRUE at the start of a new message
124 setup, to allow one of each between messages that is not counted as a nonmail
125 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
126 allow a new EHLO after starting up TLS.
128 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
129 counted. However, the flag is changed when AUTH is received, so that multiple
130 failing AUTHs will eventually hit the limit. After a successful AUTH, another
131 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
132 forced TRUE, to allow for the re-authentication that can happen at that point.
134 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
135 count of non-mail commands and possibly provoke an error. */
137 static smtp_cmd_list cmd_list[] = {
138 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
139 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
140 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
141 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
143 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
146 /* If you change anything above here, also fix the definitions below. */
148 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
149 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
150 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
151 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
152 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
153 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
154 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
155 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
156 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
159 static smtp_cmd_list *cmd_list_end =
160 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
162 #define CMD_LIST_RSET 0
163 #define CMD_LIST_HELO 1
164 #define CMD_LIST_EHLO 2
165 #define CMD_LIST_AUTH 3
166 #define CMD_LIST_STARTTLS 4
168 static uschar *protocols[] = {
169 US"local-smtp", /* HELO */
170 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
171 US"local-esmtp", /* EHLO */
172 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
173 US"local-esmtpa", /* EHLO->AUTH */
174 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
179 #define pcrpted 1 /* added to pextend or pnormal */
180 #define pauthed 2 /* added to pextend */
181 #define pnlocal 6 /* offset to remove "local" */
183 /* When reading SMTP from a remote host, we have to use our own versions of the
184 C input-reading functions, in order to be able to flush the SMTP output only
185 when about to read more data from the socket. This is the only way to get
186 optimal performance when the client is using pipelining. Flushing for every
187 command causes a separate packet and reply packet each time; saving all the
188 responses up (when pipelining) combines them into one packet and one response.
190 For simplicity, these functions are used for *all* SMTP input, not only when
191 receiving over a socket. However, after setting up a secure socket (SSL), input
192 is read via the OpenSSL library, and another set of functions is used instead
195 These functions are set in the receive_getc etc. variables and called with the
196 same interface as the C functions. However, since there can only ever be
197 one incoming SMTP call, we just use a single buffer and flags. There is no need
198 to implement a complicated private FILE-like structure.*/
200 static uschar *smtp_inbuffer;
201 static uschar *smtp_inptr;
202 static uschar *smtp_inend;
203 static int smtp_had_eof;
204 static int smtp_had_error;
207 /*************************************************
208 * SMTP version of getc() *
209 *************************************************/
211 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
212 it flushes the output, and refills the buffer, with a timeout. The signal
213 handler is set appropriately by the calling function. This function is not used
214 after a connection has negotated itself into an TLS/SSL state.
217 Returns: the next character or EOF
223 if (smtp_inptr >= smtp_inend)
227 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
228 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
233 /* Must put the error text in fixed store, because this might be during
234 header reading, where it releases unused store above the header. */
237 smtp_had_error = save_errno;
238 smtp_read_error = string_copy_malloc(
239 string_sprintf(" (error: %s)", strerror(save_errno)));
241 else smtp_had_eof = 1;
244 smtp_inend = smtp_inbuffer + rc;
245 smtp_inptr = smtp_inbuffer;
247 return *smtp_inptr++;
252 /*************************************************
253 * SMTP version of ungetc() *
254 *************************************************/
256 /* Puts a character back in the input buffer. Only ever
262 Returns: the character
268 *(--smtp_inptr) = ch;
275 /*************************************************
276 * SMTP version of feof() *
277 *************************************************/
279 /* Tests for a previous EOF
282 Returns: non-zero if the eof flag is set
294 /*************************************************
295 * SMTP version of ferror() *
296 *************************************************/
298 /* Tests for a previous read error, and returns with errno
299 restored to what it was when the error was detected.
302 Returns: non-zero if the error flag is set
308 errno = smtp_had_error;
309 return smtp_had_error;
315 /*************************************************
316 * Write formatted string to SMTP channel *
317 *************************************************/
319 /* This is a separate function so that we don't have to repeat everything for
320 TLS support or debugging. It is global so that the daemon and the
321 authentication functions can use it. It does not return any error indication,
322 because major problems such as dropped connections won't show up till an output
323 flush for non-TLS connections. The smtp_fflush() function is available for
324 checking that: for convenience, TLS output errors are remembered here so that
325 they are also picked up later by smtp_fflush().
329 ... optional arguments
335 smtp_printf(char *format, ...)
342 va_start(ap, format);
343 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
345 end = big_buffer + Ustrlen(big_buffer);
346 while ((cr = Ustrchr(big_buffer, '\r')) != NULL) /* lose CRs */
347 memmove(cr, cr + 1, (end--) - cr);
348 debug_printf("SMTP>> %s", big_buffer);
351 va_start(ap, format);
353 /* If in a TLS session we have to format the string, and then write it using a
359 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
361 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
362 smtp_closedown(US"Unexpected error");
363 exim_exit(EXIT_FAILURE);
365 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
370 /* Otherwise, just use the standard library function. */
372 if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
378 /*************************************************
379 * Flush SMTP out and check for error *
380 *************************************************/
382 /* This function isn't currently used within Exim (it detects errors when it
383 tries to read the next SMTP input), but is available for use in local_scan().
384 For non-TLS connections, it flushes the output and checks for errors. For
385 TLS-connections, it checks for a previously-detected TLS write error.
388 Returns: 0 for no error; -1 after an error
394 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
395 return smtp_write_error;
400 /*************************************************
401 * SMTP command read timeout *
402 *************************************************/
404 /* Signal handler for timing out incoming SMTP commands. This attempts to
407 Argument: signal number (SIGALRM)
412 command_timeout_handler(int sig)
414 sig = sig; /* Keep picky compilers happy */
415 log_write(L_lost_incoming_connection,
416 LOG_MAIN, "SMTP command timeout on%s connection from %s",
417 (tls_active >= 0)? " TLS" : "",
418 host_and_ident(FALSE));
419 if (smtp_batched_input)
420 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
421 smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
422 smtp_active_hostname);
424 exim_exit(EXIT_FAILURE);
429 /*************************************************
431 *************************************************/
433 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
435 Argument: signal number (SIGTERM)
440 command_sigterm_handler(int sig)
442 sig = sig; /* Keep picky compilers happy */
443 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
444 if (smtp_batched_input)
445 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
446 smtp_printf("421 %s: Service not available - closing connection\r\n",
447 smtp_active_hostname);
448 exim_exit(EXIT_FAILURE);
453 /*************************************************
454 * Read one command line *
455 *************************************************/
457 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
458 There are sites that don't do this, and in any case internal SMTP probably
459 should check only for LF. Consequently, we check here for LF only. The line
460 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
461 an unknown command. The command is read into the global smtp_cmd_buffer so that
462 it is available via $smtp_command.
464 The character reading routine sets up a timeout for each block actually read
465 from the input (which may contain more than one command). We set up a special
466 signal handler that closes down the session on a timeout. Control does not
470 check_sync if TRUE, check synchronization rules if global option is TRUE
472 Returns: a code identifying the command (enumerated above)
476 smtp_read_command(BOOL check_sync)
481 BOOL hadnull = FALSE;
483 os_non_restarting_signal(SIGALRM, command_timeout_handler);
485 while ((c = (receive_getc)()) != '\n' && c != EOF)
487 if (ptr >= smtp_cmd_buffer_size)
489 os_non_restarting_signal(SIGALRM, sigalrm_handler);
497 smtp_cmd_buffer[ptr++] = c;
500 receive_linecount++; /* For BSMTP errors */
501 os_non_restarting_signal(SIGALRM, sigalrm_handler);
503 /* If hit end of file, return pseudo EOF command. Whether we have a
504 part-line already read doesn't matter, since this is an error state. */
506 if (c == EOF) return EOF_CMD;
508 /* Remove any CR and white space at the end of the line, and terminate the
511 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
512 smtp_cmd_buffer[ptr] = 0;
514 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
516 /* NULLs are not allowed in SMTP commands */
518 if (hadnull) return BADCHAR_CMD;
520 /* Scan command list and return identity, having set the data pointer
521 to the start of the actual data characters. Check for SMTP synchronization
524 for (p = cmd_list; p < cmd_list_end; p++)
526 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0)
528 if (smtp_inptr < smtp_inend && /* Outstanding input */
529 p->cmd < sync_cmd_limit && /* Command should sync */
530 check_sync && /* Local flag set */
531 smtp_enforce_sync && /* Global flag set */
532 sender_host_address != NULL && /* Not local input */
533 !sender_host_notsocket) /* Really is a socket */
536 /* Point after the command, but don't skip over leading spaces till after
537 the following test, so that if it fails, the command name can easily be
540 smtp_cmd_argument = smtp_cmd_buffer + p->len;
542 /* Count non-mail commands from those hosts that are controlled in this
543 way. The default is all hosts. We don't waste effort checking the list
544 until we get a non-mail command, but then cache the result to save checking
545 again. If there's a DEFER while checking the host, assume it's in the list.
547 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
548 start of each incoming message by fiddling with the value in the table. */
552 if (count_nonmail == TRUE_UNSET) count_nonmail =
553 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
554 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
555 return TOO_MANY_NONMAIL_CMD;
558 /* Get the data pointer over leading spaces and return; if there is data
559 for a command that does not expect it, give the error centrally here. */
561 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
562 return (p->has_arg || *smtp_cmd_argument == 0)? p->cmd : BADARG_CMD;
566 /* Enforce synchronization for unknown commands */
568 if (smtp_inptr < smtp_inend && /* Outstanding input */
569 check_sync && /* Local flag set */
570 smtp_enforce_sync && /* Global flag set */
571 sender_host_address != NULL && /* Not local input */
572 !sender_host_notsocket) /* Really is a socket */
580 /*************************************************
581 * Forced closedown of call *
582 *************************************************/
584 /* This function is called from log.c when Exim is dying because of a serious
585 disaster, and also from some other places. If an incoming non-batched SMTP
586 channel is open, it swallows the rest of the incoming message if in the DATA
587 phase, sends the reply string, and gives an error to all subsequent commands
588 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
591 Argument: SMTP reply string to send, excluding the code
596 smtp_closedown(uschar *message)
598 if (smtp_in == NULL || smtp_batched_input) return;
599 receive_swallow_smtp();
600 smtp_printf("421 %s\r\n", message);
604 switch(smtp_read_command(FALSE))
610 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
615 smtp_printf("250 Reset OK\r\n");
619 smtp_printf("421 %s\r\n", message);
628 /*************************************************
629 * Set up connection info for logging *
630 *************************************************/
632 /* This function is called when logging information about an SMTP connection.
633 It sets up appropriate source information, depending on the type of connection.
634 If sender_fullhost is NULL, we are at a very early stage of the connection;
635 just use the IP address.
638 Returns: a string describing the connection
642 smtp_get_connection_info(void)
644 uschar *hostname = (sender_fullhost == NULL)?
645 sender_host_address : sender_fullhost;
648 return string_sprintf("SMTP connection from %s", hostname);
650 if (sender_host_unknown || sender_host_notsocket)
651 return string_sprintf("SMTP connection from %s", sender_ident);
654 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
656 if ((log_extra_selector & LX_incoming_interface) != 0 &&
657 interface_address != NULL)
658 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
659 interface_address, interface_port);
661 return string_sprintf("SMTP connection from %s", hostname);
666 /*************************************************
667 * Check HELO line and set sender_helo_name *
668 *************************************************/
670 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
671 the domain name of the sending host, or an ip literal in square brackets. The
672 arrgument is placed in sender_helo_name, which is in malloc store, because it
673 must persist over multiple incoming messages. If helo_accept_junk is set, this
674 host is permitted to send any old junk (needed for some broken hosts).
675 Otherwise, helo_allow_chars can be used for rogue characters in general
676 (typically people want to let in underscores).
679 s the data portion of the line (already past any white space)
681 Returns: TRUE or FALSE
685 check_helo(uschar *s)
688 uschar *end = s + Ustrlen(s);
689 BOOL yield = helo_accept_junk;
691 /* Discard any previous helo name */
693 if (sender_helo_name != NULL)
695 store_free(sender_helo_name);
696 sender_helo_name = NULL;
699 /* Skip tests if junk is permitted. */
703 /* Allow the new standard form for IPv6 address literals, namely,
704 [IPv6:....], and because someone is bound to use it, allow an equivalent
705 IPv4 form. Allow plain addresses as well. */
712 if (strncmpic(s, US"[IPv6:", 6) == 0)
713 yield = (string_is_ip_address(s+6, NULL) == 6);
714 else if (strncmpic(s, US"[IPv4:", 6) == 0)
715 yield = (string_is_ip_address(s+6, NULL) == 4);
717 yield = (string_is_ip_address(s+1, NULL) != 0);
722 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
723 that have been configured (usually underscore - sigh). */
730 if (!isalnum(*s) && *s != '.' && *s != '-' &&
731 Ustrchr(helo_allow_chars, *s) == NULL)
741 /* Save argument if OK */
743 if (yield) sender_helo_name = string_copy_malloc(start);
751 /*************************************************
752 * Extract SMTP command option *
753 *************************************************/
755 /* This function picks the next option setting off the end of smtp_cmd_argument. It
756 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
757 things that can appear there.
760 name point this at the name
761 value point this at the data string
763 Returns: TRUE if found an option
767 extract_option(uschar **name, uschar **value)
770 uschar *v = smtp_cmd_argument + Ustrlen(smtp_cmd_argument) -1;
771 while (isspace(*v)) v--;
774 while (v > smtp_cmd_argument && *v != '=' && !isspace(*v)) v--;
775 if (*v != '=') return FALSE;
778 while(isalpha(n[-1])) n--;
780 if (n[-1] != ' ') return FALSE;
795 /*************************************************
796 * Reset for new message *
797 *************************************************/
799 /* This function is called whenever the SMTP session is reset from
800 within either of the setup functions.
802 Argument: the stacking pool storage reset point
807 smtp_reset(void *reset_point)
810 store_reset(reset_point);
811 recipients_list = NULL;
812 rcpt_count = rcpt_defer_count = rcpt_fail_count =
813 raw_recipients_count = recipients_count = recipients_list_max = 0;
814 message_linecount = 0;
816 acl_added_headers = NULL;
817 queue_only_policy = FALSE;
818 deliver_freeze = FALSE; /* Can be set by ACL */
819 freeze_tell = freeze_tell_config; /* Can be set by ACL */
820 fake_response = OK; /* Can be set by ACL */
821 #ifdef WITH_CONTENT_SCAN
822 no_mbox_unspool = FALSE; /* Can be set by ACL */
824 submission_mode = FALSE; /* Can be set by ACL */
825 suppress_local_fixups = FALSE; /* Can be set by ACL */
826 active_local_from_check = local_from_check; /* Can be set by ACL */
827 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
828 sender_address = NULL;
829 submission_name = NULL; /* Can be set by ACL */
830 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
831 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
832 sender_verified_list = NULL; /* No senders verified */
833 memset(sender_address_cache, 0, sizeof(sender_address_cache));
834 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
835 authenticated_sender = NULL;
836 #ifdef EXPERIMENTAL_BRIGHTMAIL
840 #ifdef EXPERIMENTAL_DOMAINKEYS
843 #ifdef EXPERIMENTAL_SPF
844 spf_header_comment = NULL;
847 spf_smtp_comment = NULL;
849 body_linecount = body_zerocount = 0;
851 sender_rate = sender_rate_limit = sender_rate_period = NULL;
852 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
853 /* Note that ratelimiters_conn persists across resets. */
855 /* The message variables follow the connection variables. */
857 for (i = 0; i < ACL_MVARS; i++) acl_var[ACL_CVARS + i] = NULL;
859 /* The message body variables use malloc store. They may be set if this is
860 not the first message in an SMTP session and the previous message caused them
861 to be referenced in an ACL. */
863 if (message_body != NULL)
865 store_free(message_body);
869 if (message_body_end != NULL)
871 store_free(message_body_end);
872 message_body_end = NULL;
875 /* Warning log messages are also saved in malloc store. They are saved to avoid
876 repetition in the same message, but it seems right to repeat them for different
879 while (acl_warn_logged != NULL)
881 string_item *this = acl_warn_logged;
882 acl_warn_logged = acl_warn_logged->next;
891 /*************************************************
892 * Initialize for incoming batched SMTP message *
893 *************************************************/
895 /* This function is called from smtp_setup_msg() in the case when
896 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
897 of messages in one file with SMTP commands between them. All errors must be
898 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
899 relevant. After an error on a sender, or an invalid recipient, the remainder
900 of the message is skipped. The value of received_protocol is already set.
903 Returns: > 0 message successfully started (reached DATA)
904 = 0 QUIT read or end of file reached
909 smtp_setup_batch_msg(void)
912 void *reset_point = store_get(0);
914 /* Save the line count at the start of each transaction - single commands
915 like HELO and RSET count as whole transactions. */
917 bsmtp_transaction_linecount = receive_linecount;
919 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
921 smtp_reset(reset_point); /* Reset for start of message */
923 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
924 value. The values are 2 larger than the required yield of the function. */
929 uschar *recipient = NULL;
930 int start, end, sender_domain, recipient_domain;
932 switch(smtp_read_command(FALSE))
934 /* The HELO/EHLO commands set sender_address_helo if they have
935 valid data; otherwise they are ignored, except that they do
936 a reset of the state. */
941 check_helo(smtp_cmd_argument);
945 smtp_reset(reset_point);
946 bsmtp_transaction_linecount = receive_linecount;
950 /* The MAIL FROM command requires an address as an operand. All we
951 do here is to parse it for syntactic correctness. The form "<>" is
952 a special case which converts into an empty string. The start/end
953 pointers in the original are not used further for this address, as
954 it is the canonical extracted address which is all that is kept. */
957 if (sender_address != NULL)
958 /* The function moan_smtp_batch() does not return. */
959 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
961 if (smtp_cmd_argument[0] == 0)
962 /* The function moan_smtp_batch() does not return. */
963 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
965 /* Reset to start of message */
967 smtp_reset(reset_point);
969 /* Apply SMTP rewrite */
971 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
972 rewrite_one(smtp_cmd_argument, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
973 US"", global_rewrite_rules) : smtp_cmd_argument;
975 /* Extract the address; the TRUE flag allows <> as valid */
978 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
981 if (raw_sender == NULL)
982 /* The function moan_smtp_batch() does not return. */
983 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
985 sender_address = string_copy(raw_sender);
987 /* Qualify unqualified sender addresses if permitted to do so. */
989 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
991 if (allow_unqualified_sender)
993 sender_address = rewrite_address_qualify(sender_address, FALSE);
994 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
995 "and rewritten\n", raw_sender);
997 /* The function moan_smtp_batch() does not return. */
998 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1004 /* The RCPT TO command requires an address as an operand. All we do
1005 here is to parse it for syntactic correctness. There may be any number
1006 of RCPT TO commands, specifying multiple senders. We build them all into
1007 a data structure that is in argc/argv format. The start/end values
1008 given by parse_extract_address are not used, as we keep only the
1009 extracted address. */
1012 if (sender_address == NULL)
1013 /* The function moan_smtp_batch() does not return. */
1014 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1016 if (smtp_cmd_argument[0] == 0)
1017 /* The function moan_smtp_batch() does not return. */
1018 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1020 /* Check maximum number allowed */
1022 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1023 /* The function moan_smtp_batch() does not return. */
1024 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1025 recipients_max_reject? "552": "452");
1027 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1028 recipient address */
1030 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1031 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
1032 global_rewrite_rules) : smtp_cmd_argument;
1034 /* rfc821_domains = TRUE; << no longer needed */
1035 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1036 &recipient_domain, FALSE);
1037 /* rfc821_domains = FALSE; << no longer needed */
1039 if (recipient == NULL)
1040 /* The function moan_smtp_batch() does not return. */
1041 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1043 /* If the recipient address is unqualified, qualify it if permitted. Then
1044 add it to the list of recipients. */
1046 if (recipient_domain == 0)
1048 if (allow_unqualified_recipient)
1050 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1052 recipient = rewrite_address_qualify(recipient, TRUE);
1054 /* The function moan_smtp_batch() does not return. */
1055 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1058 receive_add_recipient(recipient, -1);
1062 /* The DATA command is legal only if it follows successful MAIL FROM
1063 and RCPT TO commands. This function is complete when a valid DATA
1064 command is encountered. */
1067 if (sender_address == NULL || recipients_count <= 0)
1069 /* The function moan_smtp_batch() does not return. */
1070 if (sender_address == NULL)
1071 moan_smtp_batch(smtp_cmd_buffer,
1072 "503 MAIL FROM:<sender> command must precede DATA");
1074 moan_smtp_batch(smtp_cmd_buffer,
1075 "503 RCPT TO:<recipient> must precede DATA");
1079 done = 3; /* DATA successfully achieved */
1080 message_ended = END_NOTENDED; /* Indicate in middle of message */
1085 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1092 bsmtp_transaction_linecount = receive_linecount;
1103 /* The function moan_smtp_batch() does not return. */
1104 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1109 /* The function moan_smtp_batch() does not return. */
1110 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1115 /* The function moan_smtp_batch() does not return. */
1116 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1121 return done - 2; /* Convert yield values */
1127 /*************************************************
1128 * Start an SMTP session *
1129 *************************************************/
1131 /* This function is called at the start of an SMTP session. Thereafter,
1132 smtp_setup_msg() is called to initiate each separate message. This
1133 function does host-specific testing, and outputs the banner line.
1136 Returns: FALSE if the session can not continue; something has
1137 gone wrong, or the connection to the host is blocked
1141 smtp_start_session(void)
1147 /* Default values for certain variables */
1149 helo_seen = esmtp = helo_accept_junk = FALSE;
1150 count_nonmail = TRUE_UNSET;
1151 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1152 smtp_delay_mail = smtp_rlm_base;
1153 auth_advertised = FALSE;
1154 pipelining_advertised = FALSE;
1155 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1157 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1159 sender_host_authenticated = NULL;
1160 authenticated_by = NULL;
1163 tls_cipher = tls_peerdn = NULL;
1164 tls_advertised = FALSE;
1167 /* Reset ACL connection variables */
1169 for (i = 0; i < ACL_CVARS; i++) acl_var[i] = NULL;
1171 /* Allow for trailing 0 in the command buffer. */
1173 smtp_cmd_buffer = (uschar *)malloc(smtp_cmd_buffer_size + 1);
1174 if (smtp_cmd_buffer == NULL)
1175 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1176 "malloc() failed for SMTP command buffer");
1178 /* For batched input, the protocol setting can be overridden from the
1179 command line by a trusted caller. */
1181 if (smtp_batched_input)
1183 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1186 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1187 reset later if any of EHLO/AUTH/STARTTLS are received. */
1191 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1193 /* Set up the buffer for inputting using direct read() calls, and arrange to
1194 call the local functions instead of the standard C ones. */
1196 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1197 if (smtp_inbuffer == NULL)
1198 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1199 receive_getc = smtp_getc;
1200 receive_ungetc = smtp_ungetc;
1201 receive_feof = smtp_feof;
1202 receive_ferror = smtp_ferror;
1203 smtp_inptr = smtp_inend = smtp_inbuffer;
1204 smtp_had_eof = smtp_had_error = 0;
1206 /* Set up the message size limit; this may be host-specific */
1208 thismessage_size_limit = expand_string_integer(message_size_limit);
1209 if (thismessage_size_limit < 0)
1211 if (thismessage_size_limit == -1)
1212 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1213 "%s", expand_string_message);
1215 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1216 "%s", expand_string_message);
1217 smtp_closedown(US"Temporary local problem - please try later");
1221 /* When a message is input locally via the -bs or -bS options, sender_host_
1222 unknown is set unless -oMa was used to force an IP address, in which case it
1223 is checked like a real remote connection. When -bs is used from inetd, this
1224 flag is not set, causing the sending host to be checked. The code that deals
1225 with IP source routing (if configured) is never required for -bs or -bS and
1226 the flag sender_host_notsocket is used to suppress it.
1228 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1229 reserve for certain hosts and/or networks. */
1231 if (!sender_host_unknown)
1234 BOOL reserved_host = FALSE;
1236 /* Look up IP options (source routing info) on the socket if this is not an
1237 -oMa "host", and if any are found, log them and drop the connection.
1239 Linux (and others now, see below) is different to everyone else, so there
1240 has to be some conditional compilation here. Versions of Linux before 2.1.15
1241 used a structure whose name was "options". Somebody finally realized that
1242 this name was silly, and it got changed to "ip_options". I use the
1243 newer name here, but there is a fudge in the script that sets up os.h
1244 to define a macro in older Linux systems.
1246 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1247 glibc 2, which has chosen ip_opts for the structure name. This is now
1248 really a glibc thing rather than a Linux thing, so the condition name
1249 has been changed to reflect this. It is relevant also to GNU/Hurd.
1251 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1252 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1253 a special macro defined in the os.h file.
1255 Some DGUX versions on older hardware appear not to support IP options at
1256 all, so there is now a general macro which can be set to cut out this
1259 How to do this properly in IPv6 is not yet known. */
1261 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1263 #ifdef GLIBC_IP_OPTIONS
1264 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1269 #elif defined DARWIN_IP_OPTIONS
1275 if (!host_checking && !sender_host_notsocket)
1278 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1279 struct ip_options *ipopt = store_get(optlen);
1281 struct ip_opts ipoptblock;
1282 struct ip_opts *ipopt = &ipoptblock;
1283 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1285 struct ipoption ipoptblock;
1286 struct ipoption *ipopt = &ipoptblock;
1287 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1290 /* Occasional genuine failures of getsockopt() have been seen - for
1291 example, "reset by peer". Therefore, just log and give up on this
1292 call, unless the error is ENOPROTOOPT. This error is given by systems
1293 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1294 of writing. So for that error, carry on - we just can't do an IP options
1297 DEBUG(D_receive) debug_printf("checking for IP options\n");
1299 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1302 if (errno != ENOPROTOOPT)
1304 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1305 host_and_ident(FALSE), strerror(errno));
1306 smtp_printf("451 SMTP service not available\r\n");
1311 /* Deal with any IP options that are set. On the systems I have looked at,
1312 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1313 more logging data than will fit in big_buffer. Nevertheless, after somebody
1314 questioned this code, I've added in some paranoid checking. */
1316 else if (optlen > 0)
1318 uschar *p = big_buffer;
1319 uschar *pend = big_buffer + big_buffer_size;
1320 uschar *opt, *adptr;
1322 struct in_addr addr;
1325 uschar *optstart = (uschar *)(ipopt->__data);
1327 uschar *optstart = (uschar *)(ipopt->ip_opts);
1329 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1332 DEBUG(D_receive) debug_printf("IP options exist\n");
1334 Ustrcpy(p, "IP options on incoming call:");
1337 for (opt = optstart; opt != NULL &&
1338 opt < (uschar *)(ipopt) + optlen;)
1352 if (!string_format(p, pend-p, " %s [@%s",
1353 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1355 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1357 inet_ntoa(ipopt->ip_dst)))
1359 inet_ntoa(ipopt->ipopt_dst)))
1367 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1369 while (optcount-- > 0)
1371 memcpy(&addr, adptr, sizeof(addr));
1372 if (!string_format(p, pend - p - 1, "%s%s",
1373 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1379 adptr += sizeof(struct in_addr);
1388 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1391 for (i = 0; i < opt[1]; i++)
1393 sprintf(CS p, "%2.2x ", opt[i]);
1404 log_write(0, LOG_MAIN, "%s", big_buffer);
1406 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1408 log_write(0, LOG_MAIN|LOG_REJECT,
1409 "connection from %s refused (IP options)", host_and_ident(FALSE));
1411 smtp_printf("554 SMTP service not available\r\n");
1415 /* Length of options = 0 => there are no options */
1417 else DEBUG(D_receive) debug_printf("no IP options found\n");
1419 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1421 /* Set keep-alive in socket options. The option is on by default. This
1422 setting is an attempt to get rid of some hanging connections that stick in
1423 read() when the remote end (usually a dialup) goes away. */
1425 if (smtp_accept_keepalive && !sender_host_notsocket)
1426 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1428 /* If the current host matches host_lookup, set the name by doing a
1429 reverse lookup. On failure, sender_host_name will be NULL and
1430 host_lookup_failed will be TRUE. This may or may not be serious - optional
1433 if (verify_check_host(&host_lookup) == OK)
1435 (void)host_name_lookup();
1436 host_build_sender_fullhost();
1439 /* Delay this until we have the full name, if it is looked up. */
1441 set_process_info("handling incoming connection from %s",
1442 host_and_ident(FALSE));
1444 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1445 smtps port for use with older style SSL MTAs. */
1448 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1452 /* Test for explicit connection rejection */
1454 if (verify_check_host(&host_reject_connection) == OK)
1456 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1457 "from %s (host_reject_connection)", host_and_ident(FALSE));
1458 smtp_printf("554 SMTP service not available\r\n");
1462 /* Test with TCP Wrappers if so configured */
1464 #ifdef USE_TCP_WRAPPERS
1465 if (!hosts_ctl("exim",
1466 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1467 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1468 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1470 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1471 log_write(L_connection_reject,
1472 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1473 "(tcp wrappers)", host_and_ident(FALSE));
1474 smtp_printf("554 SMTP service not available\r\n");
1479 /* Check for reserved slots. Note that the count value doesn't include
1480 this process, as it gets upped in the parent process. */
1482 if (smtp_accept_max > 0 &&
1483 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1485 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1487 log_write(L_connection_reject,
1488 LOG_MAIN, "temporarily refused connection from %s: not in "
1489 "reserve list: connected=%d max=%d reserve=%d%s",
1490 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1491 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1492 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1493 "please try again later\r\n", smtp_active_hostname);
1496 reserved_host = TRUE;
1499 /* If a load level above which only messages from reserved hosts are
1500 accepted is set, check the load. For incoming calls via the daemon, the
1501 check is done in the superior process if there are no reserved hosts, to
1502 save a fork. In all cases, the load average will already be available
1503 in a global variable at this point. */
1505 if (smtp_load_reserve >= 0 &&
1506 load_average > smtp_load_reserve &&
1508 verify_check_host(&smtp_reserve_hosts) != OK)
1510 log_write(L_connection_reject,
1511 LOG_MAIN, "temporarily refused connection from %s: not in "
1512 "reserve list and load average = %.2f", host_and_ident(FALSE),
1513 (double)load_average/1000.0);
1514 smtp_printf("421 %s: Too much load; please try again later\r\n",
1515 smtp_active_hostname);
1519 /* Determine whether unqualified senders or recipients are permitted
1520 for this host. Unfortunately, we have to do this every time, in order to
1521 set the flags so that they can be inspected when considering qualifying
1522 addresses in the headers. For a site that permits no qualification, this
1523 won't take long, however. */
1525 allow_unqualified_sender =
1526 verify_check_host(&sender_unqualified_hosts) == OK;
1528 allow_unqualified_recipient =
1529 verify_check_host(&recipient_unqualified_hosts) == OK;
1531 /* Determine whether HELO/EHLO is required for this host. The requirement
1532 can be hard or soft. */
1534 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1536 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1538 /* Determine whether this hosts is permitted to send syntactic junk
1539 after a HELO or EHLO command. */
1541 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1544 /* For batch SMTP input we are now done. */
1546 if (smtp_batched_input) return TRUE;
1548 /* Run the ACL if it exists */
1550 if (acl_smtp_connect != NULL)
1553 uschar *user_msg, *log_msg;
1554 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1558 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1563 /* Output the initial message for a two-way SMTP connection. It may contain
1564 newlines, which then cause a multi-line response to be given. */
1566 s = expand_string(smtp_banner);
1568 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1569 "failed: %s", smtp_banner, expand_string_message);
1571 /* Remove any terminating newlines; might as well remove trailing space too */
1574 while (p > s && isspace(p[-1])) p--;
1577 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1578 is all contained in a single IP packet. The original code wrote out the
1579 greeting using several calls to fprint/fputc, and on busy servers this could
1580 cause it to be split over more than one packet - which caused CC:Mail to fall
1581 over when it got the second part of the greeting after sending its first
1582 command. Sigh. To try to avoid this, build the complete greeting message
1583 first, and output it in one fell swoop. This gives a better chance of it
1584 ending up as a single packet. */
1586 ss = store_get(size);
1590 do /* At least once, in case we have an empty string */
1593 uschar *linebreak = Ustrchr(p, '\n');
1594 if (linebreak == NULL)
1597 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1601 len = linebreak - p;
1602 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1604 ss = string_cat(ss, &size, &ptr, p, len);
1605 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1607 if (linebreak != NULL) p++;
1611 ss[ptr] = 0; /* string_cat leaves room for this */
1613 /* Before we write the banner, check that there is no input pending, unless
1614 this synchronisation check is disabled. */
1616 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1619 struct timeval tzero;
1623 FD_SET(fileno(smtp_in), &fds);
1624 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1627 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1630 if (rc > 150) rc = 150;
1631 smtp_inbuffer[rc] = 0;
1632 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1633 "synchronization error (input sent without waiting for greeting): "
1634 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1635 string_printing(smtp_inbuffer));
1636 smtp_printf("554 SMTP synchronization error\r\n");
1642 /* Now output the banner */
1644 smtp_printf("%s", ss);
1652 /*************************************************
1653 * Handle SMTP syntax and protocol errors *
1654 *************************************************/
1656 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1657 to do so. Then transmit the error response. The return value depends on the
1658 number of syntax and protocol errors in this SMTP session.
1661 type error type, given as a log flag bit
1662 code response code; <= 0 means don't send a response
1663 data data to reflect in the response (can be NULL)
1664 errmess the error message
1666 Returns: -1 limit of syntax/protocol errors NOT exceeded
1667 +1 limit of syntax/protocol errors IS exceeded
1669 These values fit in with the values of the "done" variable in the main
1670 processing loop in smtp_setup_msg(). */
1673 synprot_error(int type, int code, uschar *data, uschar *errmess)
1677 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1678 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1679 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1681 if (++synprot_error_count > smtp_max_synprot_errors)
1684 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1685 "syntax or protocol errors (last command was \"%s\")",
1686 host_and_ident(FALSE), smtp_cmd_buffer);
1691 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1692 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1694 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1703 /*************************************************
1704 * Log incomplete transactions *
1705 *************************************************/
1707 /* This function is called after a transaction has been aborted by RSET, QUIT,
1708 connection drops or other errors. It logs the envelope information received
1709 so far in order to preserve address verification attempts.
1711 Argument: string to indicate what aborted the transaction
1716 incomplete_transaction_log(uschar *what)
1718 if (sender_address == NULL || /* No transaction in progress */
1719 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1722 /* Build list of recipients for logging */
1724 if (recipients_count > 0)
1727 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1728 for (i = 0; i < recipients_count; i++)
1729 raw_recipients[i] = recipients_list[i].address;
1730 raw_recipients_count = recipients_count;
1733 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1734 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1740 /*************************************************
1741 * Send SMTP response, possibly multiline *
1742 *************************************************/
1744 /* There are, it seems, broken clients out there that cannot handle multiline
1745 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1746 output nothing for non-final calls, and only the first line for anything else.
1750 final FALSE if the last line isn't the final line
1751 msg message text, possibly containing newlines
1757 smtp_respond(int code, BOOL final, uschar *msg)
1759 if (!final && no_multiline_responses) return;
1763 uschar *nl = Ustrchr(msg, '\n');
1766 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1769 else if (nl[1] == 0 || no_multiline_responses)
1771 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1776 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1778 while (isspace(*msg)) msg++;
1786 /*************************************************
1787 * Handle an ACL failure *
1788 *************************************************/
1790 /* This function is called when acl_check() fails. As well as calls from within
1791 this module, it is called from receive.c for an ACL after DATA. It sorts out
1792 logging the incident, and sets up the error response. A message containing
1793 newlines is turned into a multiline SMTP response, but for logging, only the
1796 There's a table of the response codes to use in globals.c, along with the table
1797 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1798 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1799 that the response should be 252 in the disabled state, because there are broken
1800 clients that try VRFY before RCPT. A 5xx response should be given only when the
1801 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1802 given on refusal, and for AUTH, 503.
1805 where where the ACL was called from
1807 user_msg a message that can be included in an SMTP response
1808 log_msg a message for logging
1810 Returns: 0 in most cases
1811 2 if the failure code was FAIL_DROP, in which case the
1812 SMTP connection should be dropped (this value fits with the
1813 "done" variable in smtp_setup_msg() below)
1817 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1819 int code = acl_wherecodes[where];
1820 BOOL drop = rc == FAIL_DROP;
1822 uschar *sender_info = US"";
1824 #ifdef WITH_CONTENT_SCAN
1825 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1827 (where == ACL_WHERE_PREDATA)? US"DATA" :
1828 (where == ACL_WHERE_DATA)? US"after DATA" :
1829 (smtp_cmd_argument == NULL)?
1830 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
1831 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_argument);
1833 if (drop) rc = FAIL;
1835 /* We used to have sender_address here; however, there was a bug that was not
1836 updating sender_address after a rewrite during a verify. When this bug was
1837 fixed, sender_address at this point became the rewritten address. I'm not sure
1838 this is what should be logged, so I've changed to logging the unrewritten
1839 address to retain backward compatibility. */
1841 #ifndef WITH_CONTENT_SCAN
1842 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1844 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1847 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1848 sender_address_unrewritten : sender_address);
1851 /* If there's been a sender verification failure with a specific message, and
1852 we have not sent a response about it yet, do so now, as a preliminary line for
1853 failures, but not defers. However, always log it for defer, and log it for fail
1854 unless the sender_verify_fail log selector has been turned off. */
1856 if (sender_verified_failed != NULL &&
1857 !testflag(sender_verified_failed, af_sverify_told))
1859 setflag(sender_verified_failed, af_sverify_told);
1861 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
1862 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1863 host_and_ident(TRUE),
1864 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
1865 sender_verified_failed->address,
1866 (sender_verified_failed->message == NULL)? US"" :
1867 string_sprintf(": %s", sender_verified_failed->message));
1869 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1870 smtp_respond(code, FALSE, string_sprintf(
1871 testflag(sender_verified_failed, af_verify_pmfail)?
1872 "Postmaster verification failed while checking <%s>\n%s\n"
1873 "Several RFCs state that you are required to have a postmaster\n"
1874 "mailbox for each mail domain. This host does not accept mail\n"
1875 "from domains whose servers reject the postmaster address."
1877 testflag(sender_verified_failed, af_verify_nsfail)?
1878 "Callback setup failed while verifying <%s>\n%s\n"
1879 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1880 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1881 "RFC requirements, and stops you from receiving standard bounce\n"
1882 "messages. This host does not accept mail from domains whose servers\n"
1885 "Verification failed for <%s>\n%s",
1886 sender_verified_failed->address,
1887 sender_verified_failed->user_message));
1890 /* Sort out text for logging */
1892 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1893 lognl = Ustrchr(log_msg, '\n');
1894 if (lognl != NULL) *lognl = 0;
1896 /* Send permanent failure response to the command, but the code used isn't
1897 always a 5xx one - see comments at the start of this function. If the original
1898 rc was FAIL_DROP we drop the connection and yield 2. */
1900 if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1901 US"Administrative prohibition" : user_msg);
1903 /* Send temporary failure response to the command. Don't give any details,
1904 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1905 verb, and for a header verify when smtp_return_error_details is set.
1907 This conditional logic is all somewhat of a mess because of the odd
1908 interactions between temp_details and return_error_details. One day it should
1909 be re-implemented in a tidier fashion. */
1913 if (acl_temp_details && user_msg != NULL)
1915 if (smtp_return_error_details &&
1916 sender_verified_failed != NULL &&
1917 sender_verified_failed->message != NULL)
1919 smtp_respond(451, FALSE, sender_verified_failed->message);
1921 smtp_respond(451, TRUE, user_msg);
1924 smtp_printf("451 Temporary local problem - please try later\r\n");
1927 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
1928 Otherwise, log why it is closing if required and return 2. */
1930 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1931 host_and_ident(TRUE),
1932 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1934 if (!drop) return 0;
1936 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1937 smtp_get_connection_info());
1944 /*************************************************
1945 * Verify HELO argument *
1946 *************************************************/
1948 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
1949 matched. It is also called from ACL processing if verify = helo is used and
1950 verification was not previously tried (i.e. helo_try_verify_hosts was not
1951 matched). The result of its processing is to set helo_verified and
1952 helo_verify_failed. These variables should both be FALSE for this function to
1955 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
1956 for IPv6 ::ffff: literals.
1959 Returns: TRUE if testing was completed;
1960 FALSE on a temporary failure
1964 smtp_verify_helo(void)
1968 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
1971 if (sender_helo_name == NULL)
1973 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
1976 else if (sender_helo_name[0] == '[')
1978 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
1979 Ustrlen(sender_host_address)) == 0;
1984 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
1985 helo_verified = Ustrncmp(sender_helo_name + 1,
1986 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
1991 { if (helo_verified) debug_printf("matched host address\n"); }
1994 /* Do a reverse lookup if one hasn't already given a positive or negative
1995 response. If that fails, or the name doesn't match, try checking with a forward
2000 if (sender_host_name == NULL && !host_lookup_failed)
2001 yield = host_name_lookup() != DEFER;
2003 /* If a host name is known, check it and all its aliases. */
2005 if (sender_host_name != NULL)
2007 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2011 HDEBUG(D_receive) debug_printf("matched host name\n");
2015 uschar **aliases = sender_host_aliases;
2016 while (*aliases != NULL)
2018 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2019 if (helo_verified) break;
2024 debug_printf("matched alias %s\n", *(--aliases));
2029 /* Final attempt: try a forward lookup of the helo name */
2035 h.name = sender_helo_name;
2039 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2041 rc = host_find_byname(&h, NULL, NULL, TRUE);
2042 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2047 if (Ustrcmp(hh->address, sender_host_address) == 0)
2049 helo_verified = TRUE;
2051 debug_printf("IP address for %s matches calling address\n",
2061 if (!helo_verified) helo_verify_failed = FALSE; /* We've tried ... */
2068 /*************************************************
2069 * Initialize for SMTP incoming message *
2070 *************************************************/
2072 /* This function conducts the initial dialogue at the start of an incoming SMTP
2073 message, and builds a list of recipients. However, if the incoming message
2074 is part of a batch (-bS option) a separate function is called since it would
2075 be messy having tests splattered about all over this function. This function
2076 therefore handles the case where interaction is occurring. The input and output
2077 files are set up in smtp_in and smtp_out.
2079 The global recipients_list is set to point to a vector of recipient_item
2080 blocks, whose number is given by recipients_count. This is extended by the
2081 receive_add_recipient() function. The global variable sender_address is set to
2082 the sender's address. The yield is +1 if a message has been successfully
2083 started, 0 if a QUIT command was encountered or the connection was refused from
2084 the particular host, or -1 if the connection was lost.
2088 Returns: > 0 message successfully started (reached DATA)
2089 = 0 QUIT read or end of file reached or call refused
2094 smtp_setup_msg(void)
2097 BOOL toomany = FALSE;
2098 BOOL discarded = FALSE;
2099 BOOL last_was_rej_mail = FALSE;
2100 BOOL last_was_rcpt = FALSE;
2101 void *reset_point = store_get(0);
2103 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2105 /* Reset for start of new message. We allow one RSET not to be counted as a
2106 nonmail command, for those MTAs that insist on sending it between every
2107 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2108 TLS between messages (an Exim client may do this if it has messages queued up
2109 for the host). Note: we do NOT reset AUTH at this point. */
2111 smtp_reset(reset_point);
2112 message_ended = END_NOTSTARTED;
2114 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2115 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2116 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2118 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2121 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2123 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2125 /* Batched SMTP is handled in a different function. */
2127 if (smtp_batched_input) return smtp_setup_batch_msg();
2129 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2130 value. The values are 2 larger than the required yield of the function. */
2135 uschar *etrn_command;
2136 uschar *etrn_serialize_key;
2138 uschar *user_msg, *log_msg;
2139 uschar *recipient = NULL;
2140 uschar *hello = NULL;
2141 uschar *set_id = NULL;
2143 BOOL was_rej_mail = FALSE;
2144 BOOL was_rcpt = FALSE;
2145 void (*oldsignal)(int);
2147 int start, end, sender_domain, recipient_domain;
2152 switch(smtp_read_command(TRUE))
2154 /* The AUTH command is not permitted to occur inside a transaction, and may
2155 occur successfully only once per connection. Actually, that isn't quite
2156 true. When TLS is started, all previous information about a connection must
2157 be discarded, so a new AUTH is permitted at that time.
2159 AUTH may only be used when it has been advertised. However, it seems that
2160 there are clients that send AUTH when it hasn't been advertised, some of
2161 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2162 So there's a get-out that allows this to happen.
2164 AUTH is initially labelled as a "nonmail command" so that one occurrence
2165 doesn't get counted. We change the label here so that multiple failing
2166 AUTHS will eventually hit the nonmail threshold. */
2169 authentication_failed = TRUE;
2170 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2172 if (!auth_advertised && !allow_auth_unadvertised)
2174 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2175 US"AUTH command used when not advertised");
2178 if (sender_host_authenticated != NULL)
2180 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2181 US"already authenticated");
2184 if (sender_address != NULL)
2186 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2187 US"not permitted in mail transaction");
2193 if (acl_smtp_auth != NULL)
2195 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2198 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2203 /* Find the name of the requested authentication mechanism. */
2205 s = smtp_cmd_argument;
2206 while ((c = *smtp_cmd_argument) != 0 && !isspace(c))
2208 if (!isalnum(c) && c != '-' && c != '_')
2210 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2211 US"invalid character in authentication mechanism name");
2214 smtp_cmd_argument++;
2217 /* If not at the end of the line, we must be at white space. Terminate the
2218 name and move the pointer on to any data that may be present. */
2220 if (*smtp_cmd_argument != 0)
2222 *smtp_cmd_argument++ = 0;
2223 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
2226 /* Search for an authentication mechanism which is configured for use
2227 as a server and which has been advertised (unless, sigh, allow_auth_
2228 unadvertised is set). */
2230 for (au = auths; au != NULL; au = au->next)
2232 if (strcmpic(s, au->public_name) == 0 && au->server &&
2233 (au->advertised || allow_auth_unadvertised)) break;
2238 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2239 string_sprintf("%s authentication mechanism not supported", s));
2243 /* Run the checking code, passing the remainder of the command line as
2244 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2245 it as the only set numerical variable. The authenticator may set $auth<n>
2246 and also set other numeric variables. The $auth<n> variables are preferred
2247 nowadays; the numerical variables remain for backwards compatibility.
2249 Afterwards, have a go at expanding the set_id string, even if
2250 authentication failed - for bad passwords it can be useful to log the
2251 userid. On success, require set_id to expand and exist, and put it in
2252 authenticated_id. Save this in permanent store, as the working store gets
2253 reset at HELO, RSET, etc. */
2255 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2257 expand_nlength[0] = 0; /* $0 contains nothing */
2259 c = (au->info->servercode)(au, smtp_cmd_argument);
2260 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2261 expand_nmax = -1; /* Reset numeric variables */
2262 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2264 /* The value of authenticated_id is stored in the spool file and printed in
2265 log lines. It must not contain binary zeros or newline characters. In
2266 normal use, it never will, but when playing around or testing, this error
2267 can (did) happen. To guard against this, ensure that the id contains only
2268 printing characters. */
2270 if (set_id != NULL) set_id = string_printing(set_id);
2272 /* For the non-OK cases, set up additional logging data if set_id
2277 if (set_id != NULL && *set_id != 0)
2278 set_id = string_sprintf(" (set_id=%s)", set_id);
2282 /* Switch on the result */
2287 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2289 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2290 sender_host_authenticated = au->name;
2291 authentication_failed = FALSE;
2293 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2294 ((sender_host_address != NULL)? pnlocal : 0);
2295 s = ss = US"235 Authentication succeeded";
2296 authenticated_by = au;
2300 /* Authentication succeeded, but we failed to expand the set_id string.
2301 Treat this as a temporary error. */
2303 auth_defer_msg = expand_string_message;
2307 s = string_sprintf("435 Unable to authenticate at present%s",
2308 auth_defer_user_msg);
2309 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2310 set_id, auth_defer_msg);
2314 s = ss = US"501 Invalid base64 data";
2318 s = ss = US"501 Authentication cancelled";
2322 s = ss = US"553 Initial data not expected";
2326 s = US"535 Incorrect authentication data";
2327 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2331 s = US"435 Internal error";
2332 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2333 "check", set_id, c);
2337 smtp_printf("%s\r\n", s);
2339 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2340 au->name, host_and_ident(FALSE), ss);
2342 break; /* AUTH_CMD */
2344 /* The HELO/EHLO commands are permitted to appear in the middle of a
2345 session as well as at the beginning. They have the effect of a reset in
2346 addition to their other functions. Their absence at the start cannot be
2347 taken to be an error.
2351 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2352 or 502 failure replies MUST be returned as appropriate. The SMTP
2353 server MUST stay in the same state after transmitting these replies
2354 that it was in before the EHLO was received.
2356 Therefore, we do not do the reset until after checking the command for
2357 acceptability. This change was made for Exim release 4.11. Previously
2358 it did the reset first. */
2369 HELO_EHLO: /* Common code for HELO and EHLO */
2370 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2371 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2373 /* Reject the HELO if its argument was invalid or non-existent. A
2374 successful check causes the argument to be saved in malloc store. */
2376 if (!check_helo(smtp_cmd_argument))
2378 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2380 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2381 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2382 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2383 string_printing(smtp_cmd_argument));
2385 if (++synprot_error_count > smtp_max_synprot_errors)
2387 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2388 "syntax or protocol errors (last command was \"%s\")",
2389 host_and_ident(FALSE), smtp_cmd_buffer);
2396 /* If sender_host_unknown is true, we have got here via the -bs interface,
2397 not called from inetd. Otherwise, we are running an IP connection and the
2398 host address will be set. If the helo name is the primary name of this
2399 host and we haven't done a reverse lookup, force one now. If helo_required
2400 is set, ensure that the HELO name matches the actual host. If helo_verify
2401 is set, do the same check, but softly. */
2403 if (!sender_host_unknown)
2405 BOOL old_helo_verified = helo_verified;
2406 uschar *p = smtp_cmd_argument;
2408 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2411 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2412 because otherwise the log can be confusing. */
2414 if (sender_host_name == NULL &&
2415 (deliver_domain = sender_helo_name, /* set $domain */
2416 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2417 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2418 (void)host_name_lookup();
2420 /* Rebuild the fullhost info to include the HELO name (and the real name
2421 if it was looked up.) */
2423 host_build_sender_fullhost(); /* Rebuild */
2424 set_process_info("handling%s incoming connection from %s",
2425 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2427 /* Verify if configured. This doesn't give much security, but it does
2428 make some people happy to be able to do it. If helo_required is set,
2429 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2430 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2431 now obsolescent, since the verification can now be requested selectively
2434 helo_verified = helo_verify_failed = FALSE;
2435 if (helo_required || helo_verify)
2437 BOOL tempfail = !smtp_verify_helo();
2442 smtp_printf("%d %s argument does not match calling host\r\n",
2443 tempfail? 451 : 550, hello);
2444 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2445 tempfail? "temporarily " : "",
2446 hello, sender_helo_name, host_and_ident(FALSE));
2447 helo_verified = old_helo_verified;
2448 break; /* End of HELO/EHLO processing */
2450 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2451 "helo_try_verify_hosts\n", hello);
2456 #ifdef EXPERIMENTAL_SPF
2457 /* set up SPF context */
2458 spf_init(sender_helo_name, sender_host_address);
2461 /* Apply an ACL check if one is defined */
2463 if (acl_smtp_helo != NULL)
2465 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2468 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2469 sender_helo_name = NULL;
2470 host_build_sender_fullhost(); /* Rebuild */
2475 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2476 abandoning any previous message. */
2478 received_protocol = (esmtp?
2480 ((sender_host_authenticated != NULL)? pauthed : 0) +
2481 ((tls_active >= 0)? pcrpted : 0)]
2483 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2485 ((sender_host_address != NULL)? pnlocal : 0);
2487 smtp_reset(reset_point);
2490 /* Generate an OK reply, including the ident if present, and also
2491 the IP address if present. Reflecting back the ident is intended
2492 as a deterrent to mail forgers. For maximum efficiency, and also
2493 because some broken systems expect each response to be in a single
2494 packet, arrange that it is sent in one write(). */
2496 auth_advertised = FALSE;
2497 pipelining_advertised = FALSE;
2499 tls_advertised = FALSE;
2502 s = string_sprintf("250 %s Hello %s%s%s",
2503 smtp_active_hostname,
2504 (sender_ident == NULL)? US"" : sender_ident,
2505 (sender_ident == NULL)? US"" : US" at ",
2506 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2511 if (sender_host_address != NULL)
2513 s = string_cat(s, &size, &ptr, US" [", 2);
2514 s = string_cat(s, &size, &ptr, sender_host_address,
2515 Ustrlen(sender_host_address));
2516 s = string_cat(s, &size, &ptr, US"]", 1);
2519 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2521 /* If we received EHLO, we must create a multiline response which includes
2522 the functions supported. */
2528 /* I'm not entirely happy with this, as an MTA is supposed to check
2529 that it has enough room to accept a message of maximum size before
2530 it sends this. However, there seems little point in not sending it.
2531 The actual size check happens later at MAIL FROM time. By postponing it
2532 till then, VRFY and EXPN can be used after EHLO when space is short. */
2534 if (thismessage_size_limit > 0)
2536 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2537 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2541 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2544 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2545 clean; if it has an 8-bit character in its hand, it just sends it. It
2546 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2547 However, some users want this option simply in order to stop MUAs
2548 mangling messages that contain top-bit-set characters. It is therefore
2549 provided as an option. */
2551 if (accept_8bitmime)
2552 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2554 /* Advertise ETRN if there's an ACL checking whether a host is
2555 permitted to issue it; a check is made when any host actually tries. */
2557 if (acl_smtp_etrn != NULL)
2559 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2562 /* Advertise EXPN if there's an ACL checking whether a host is
2563 permitted to issue it; a check is made when any host actually tries. */
2565 if (acl_smtp_expn != NULL)
2567 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2570 /* Exim is quite happy with pipelining, so let the other end know that
2571 it is safe to use it, unless advertising is disabled. */
2573 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2575 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2576 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2577 pipelining_advertised = TRUE;
2580 /* If any server authentication mechanisms are configured, advertise
2581 them if the current host is in auth_advertise_hosts. The problem with
2582 advertising always is that some clients then require users to
2583 authenticate (and aren't configurable otherwise) even though it may not
2584 be necessary (e.g. if the host is in host_accept_relay).
2586 RFC 2222 states that SASL mechanism names contain only upper case
2587 letters, so output the names in upper case, though we actually recognize
2588 them in either case in the AUTH command. */
2592 if (verify_check_host(&auth_advertise_hosts) == OK)
2596 for (au = auths; au != NULL; au = au->next)
2598 if (au->server && (au->advertise_condition == NULL ||
2599 expand_check_condition(au->advertise_condition, au->name,
2600 US"authenticator")))
2605 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2607 auth_advertised = TRUE;
2610 s = string_cat(s, &size, &ptr, US" ", 1);
2611 s = string_cat(s, &size, &ptr, au->public_name,
2612 Ustrlen(au->public_name));
2613 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2614 au->advertised = TRUE;
2616 else au->advertised = FALSE;
2618 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2622 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2623 if it has been included in the binary, and the host matches
2624 tls_advertise_hosts. We must *not* advertise if we are already in a
2625 secure connection. */
2628 if (tls_active < 0 &&
2629 verify_check_host(&tls_advertise_hosts) != FAIL)
2631 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2632 tls_advertised = TRUE;
2636 /* Finish off the multiline reply with one that is always available. */
2638 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2641 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2647 if (tls_active >= 0) (void)tls_write(s, ptr); else
2650 (void)fwrite(s, 1, ptr, smtp_out);
2654 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
2655 memmove(cr, cr + 1, (ptr--) - (cr - s));
2656 debug_printf("SMTP>> %s", s);
2659 break; /* HELO/EHLO */
2662 /* The MAIL command requires an address as an operand. All we do
2663 here is to parse it for syntactic correctness. The form "<>" is
2664 a special case which converts into an empty string. The start/end
2665 pointers in the original are not used further for this address, as
2666 it is the canonical extracted address which is all that is kept. */
2669 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2670 was_rej_mail = TRUE; /* Reset if accepted */
2672 if (helo_required && !helo_seen)
2674 smtp_printf("503 HELO or EHLO required\r\n");
2675 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2676 "HELO/EHLO given", host_and_ident(FALSE));
2680 if (sender_address != NULL)
2682 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2683 US"sender already given");
2687 if (smtp_cmd_argument[0] == 0)
2689 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2690 US"MAIL must have an address operand");
2694 /* Check to see if the limit for messages per connection would be
2695 exceeded by accepting further messages. */
2697 if (smtp_accept_max_per_connection > 0 &&
2698 smtp_mailcmd_count > smtp_accept_max_per_connection)
2700 smtp_printf("421 too many messages in this connection\r\n");
2701 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2702 "messages in one connection", host_and_ident(TRUE));
2706 /* Reset for start of message - even if this is going to fail, we
2707 obviously need to throw away any previous data. */
2709 smtp_reset(reset_point);
2711 sender_data = recipient_data = NULL;
2713 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2717 uschar *name, *value, *end;
2718 unsigned long int size;
2720 if (!extract_option(&name, &value)) break;
2722 /* Handle SIZE= by reading the value. We don't do the check till later,
2723 in order to be able to log the sender address on failure. */
2725 if (strcmpic(name, US"SIZE") == 0 &&
2726 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2728 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2730 message_size = (int)size;
2733 /* If this session was initiated with EHLO and accept_8bitmime is set,
2734 Exim will have indicated that it supports the BODY=8BITMIME option. In
2735 fact, it does not support this according to the RFCs, in that it does not
2736 take any special action for forwarding messages containing 8-bit
2737 characters. That is why accept_8bitmime is not the default setting, but
2738 some sites want the action that is provided. We recognize both "8BITMIME"
2739 and "7BIT" as body types, but take no action. */
2741 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2742 (strcmpic(value, US"8BITMIME") == 0 ||
2743 strcmpic(value, US"7BIT") == 0)) {}
2745 /* Handle the AUTH extension. If the value given is not "<>" and either
2746 the ACL says "yes" or there is no ACL but the sending host is
2747 authenticated, we set it up as the authenticated sender. However, if the
2748 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2749 the condition is met. The value of AUTH is an xtext, which means that +,
2750 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2753 else if (strcmpic(name, US"AUTH") == 0)
2755 if (Ustrcmp(value, "<>") != 0)
2760 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2762 /* Put back terminator overrides for error message */
2765 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2766 US"invalid data for AUTH");
2770 if (acl_smtp_mailauth == NULL)
2772 ignore_msg = US"client not authenticated";
2773 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2777 ignore_msg = US"rejected by ACL";
2778 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2779 &user_msg, &log_msg);
2785 if (authenticated_by == NULL ||
2786 authenticated_by->mail_auth_condition == NULL ||
2787 expand_check_condition(authenticated_by->mail_auth_condition,
2788 authenticated_by->name, US"authenticator"))
2789 break; /* Accept the AUTH */
2791 ignore_msg = US"server_mail_auth_condition failed";
2792 if (authenticated_id != NULL)
2793 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2794 ignore_msg, authenticated_id);
2799 authenticated_sender = NULL;
2800 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2801 value, host_and_ident(TRUE), ignore_msg);
2804 /* Should only get DEFER or ERROR here. Put back terminator
2805 overrides for error message */
2810 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2817 /* Unknown option. Stick back the terminator characters and break
2818 the loop. An error for a malformed address will occur. */
2828 /* If we have passed the threshold for rate limiting, apply the current
2829 delay, and update it for next time, provided this is a limited host. */
2831 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2832 verify_check_host(&smtp_ratelimit_hosts) == OK)
2834 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2835 smtp_delay_mail/1000.0);
2836 millisleep((int)smtp_delay_mail);
2837 smtp_delay_mail *= smtp_rlm_factor;
2838 if (smtp_delay_mail > (double)smtp_rlm_limit)
2839 smtp_delay_mail = (double)smtp_rlm_limit;
2842 /* Now extract the address, first applying any SMTP-time rewriting. The
2843 TRUE flag allows "<>" as a sender address. */
2845 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2846 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
2847 global_rewrite_rules) : smtp_cmd_argument;
2849 /* rfc821_domains = TRUE; << no longer needed */
2851 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2853 /* rfc821_domains = FALSE; << no longer needed */
2855 if (raw_sender == NULL)
2857 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
2861 sender_address = raw_sender;
2863 /* If there is a configured size limit for mail, check that this message
2864 doesn't exceed it. The check is postponed to this point so that the sender
2867 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2869 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2870 log_write(L_size_reject,
2871 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2872 "message too big: size%s=%d max=%d",
2874 host_and_ident(TRUE),
2875 (message_size == INT_MAX)? ">" : "",
2877 thismessage_size_limit);
2878 sender_address = NULL;
2882 /* Check there is enough space on the disk unless configured not to.
2883 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2884 plus the current message - i.e. we accept the message only if it won't
2885 reduce the space below the threshold. Add 5000 to the size to allow for
2886 overheads such as the Received: line and storing of recipients, etc.
2887 By putting the check here, even when SIZE is not given, it allow VRFY
2888 and EXPN etc. to be used when space is short. */
2890 if (!receive_check_fs(
2891 (smtp_check_spool_space && message_size >= 0)?
2892 message_size + 5000 : 0))
2894 smtp_printf("452 Space shortage, please try later\r\n");
2895 sender_address = NULL;
2899 /* If sender_address is unqualified, reject it, unless this is a locally
2900 generated message, or the sending host or net is permitted to send
2901 unqualified addresses - typically local machines behaving as MUAs -
2902 in which case just qualify the address. The flag is set above at the start
2903 of the SMTP connection. */
2905 if (sender_domain == 0 && sender_address[0] != 0)
2907 if (allow_unqualified_sender)
2909 sender_domain = Ustrlen(sender_address) + 1;
2910 sender_address = rewrite_address_qualify(sender_address, FALSE);
2911 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2916 smtp_printf("501 %s: sender address must contain a domain\r\n",
2918 log_write(L_smtp_syntax_error,
2919 LOG_MAIN|LOG_REJECT,
2920 "unqualified sender rejected: <%s> %s%s",
2922 host_and_ident(TRUE),
2924 sender_address = NULL;
2929 /* Apply an ACL check if one is defined, before responding */
2931 rc = (acl_smtp_mail == NULL)? OK :
2932 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2934 if (rc == OK || rc == DISCARD)
2936 smtp_printf("250 OK\r\n");
2937 smtp_delay_rcpt = smtp_rlr_base;
2938 recipients_discarded = (rc == DISCARD);
2939 was_rej_mail = FALSE;
2944 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2945 sender_address = NULL;
2950 /* The RCPT command requires an address as an operand. All we do
2951 here is to parse it for syntactic correctness. There may be any number
2952 of RCPT commands, specifying multiple senders. We build them all into
2953 a data structure that is in argc/argv format. The start/end values
2954 given by parse_extract_address are not used, as we keep only the
2955 extracted address. */
2961 /* There must be a sender address; if the sender was rejected and
2962 pipelining was advertised, we assume the client was pipelining, and do not
2963 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2964 get the same treatment. */
2966 if (sender_address == NULL)
2968 if (pipelining_advertised && last_was_rej_mail)
2970 smtp_printf("503 sender not yet given\r\n");
2971 was_rej_mail = TRUE;
2975 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2976 US"sender not yet given");
2977 was_rcpt = FALSE; /* Not a valid RCPT */
2983 /* Check for an operand */
2985 if (smtp_cmd_argument[0] == 0)
2987 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2988 US"RCPT must have an address operand");
2993 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2994 as a recipient address */
2996 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2997 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
2998 global_rewrite_rules) : smtp_cmd_argument;
3000 /* rfc821_domains = TRUE; << no longer needed */
3001 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3002 &recipient_domain, FALSE);
3003 /* rfc821_domains = FALSE; << no longer needed */
3005 if (recipient == NULL)
3007 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
3012 /* If the recipient address is unqualified, reject it, unless this is a
3013 locally generated message. However, unqualified addresses are permitted
3014 from a configured list of hosts and nets - typically when behaving as
3015 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3016 really. The flag is set at the start of the SMTP connection.
3018 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3019 assumed this meant "reserved local part", but the revision of RFC 821 and
3020 friends now makes it absolutely clear that it means *mailbox*. Consequently
3021 we must always qualify this address, regardless. */
3023 if (recipient_domain == 0)
3025 if (allow_unqualified_recipient ||
3026 strcmpic(recipient, US"postmaster") == 0)
3028 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3030 recipient_domain = Ustrlen(recipient) + 1;
3031 recipient = rewrite_address_qualify(recipient, TRUE);
3036 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3038 log_write(L_smtp_syntax_error,
3039 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3040 "<%s> %s%s", recipient, host_and_ident(TRUE),
3046 /* Check maximum allowed */
3048 if (rcpt_count > recipients_max && recipients_max > 0)
3050 if (recipients_max_reject)
3053 smtp_printf("552 too many recipients\r\n");
3055 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3056 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3061 smtp_printf("452 too many recipients\r\n");
3063 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3064 "temporarily rejected: sender=<%s> %s", sender_address,
3065 host_and_ident(TRUE));
3072 /* If we have passed the threshold for rate limiting, apply the current
3073 delay, and update it for next time, provided this is a limited host. */
3075 if (rcpt_count > smtp_rlr_threshold &&
3076 verify_check_host(&smtp_ratelimit_hosts) == OK)
3078 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3079 smtp_delay_rcpt/1000.0);
3080 millisleep((int)smtp_delay_rcpt);
3081 smtp_delay_rcpt *= smtp_rlr_factor;
3082 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3083 smtp_delay_rcpt = (double)smtp_rlr_limit;
3086 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3087 for them. Otherwise, check the access control list for this recipient. */
3089 rc = recipients_discarded? DISCARD :
3090 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3092 /* The ACL was happy */
3096 smtp_printf("250 Accepted\r\n");
3097 receive_add_recipient(recipient, -1);
3100 /* The recipient was discarded */
3102 else if (rc == DISCARD)
3104 smtp_printf("250 Accepted\r\n");
3107 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3108 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3109 (sender_address_unrewritten != NULL)?
3110 sender_address_unrewritten : sender_address,
3111 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3112 (log_msg == NULL)? US"" : US": ",
3113 (log_msg == NULL)? US"" : log_msg);
3116 /* Either the ACL failed the address, or it was deferred. */
3120 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3121 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3126 /* The DATA command is legal only if it follows successful MAIL FROM
3127 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3128 not counted as a protocol error if it follows RCPT (which must have been
3129 rejected if there are no recipients.) This function is complete when a
3130 valid DATA command is encountered.
3132 Note concerning the code used: RFC 2821 says this:
3134 - If there was no MAIL, or no RCPT, command, or all such commands
3135 were rejected, the server MAY return a "command out of sequence"
3136 (503) or "no valid recipients" (554) reply in response to the
3139 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3140 because it is the same whether pipelining is in use or not. */
3143 if (!discarded && recipients_count <= 0)
3145 if (pipelining_advertised && last_was_rcpt)
3146 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3148 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3149 US"valid RCPT command must precede DATA");
3153 if (toomany && recipients_max_reject)
3155 sender_address = NULL; /* This will allow a new MAIL without RSET */
3156 sender_address_unrewritten = NULL;
3157 smtp_printf("554 Too many recipients\r\n");
3161 if (acl_smtp_predata == NULL) rc = OK; else
3163 enable_dollar_recipients = TRUE;
3164 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3166 enable_dollar_recipients = FALSE;
3171 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3173 message_ended = END_NOTENDED; /* Indicate in middle of data */
3176 /* Either the ACL failed the address, or it was deferred. */
3179 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3185 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3187 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3193 /* rfc821_domains = TRUE; << no longer needed */
3194 address = parse_extract_address(smtp_cmd_argument, &errmess, &start, &end,
3195 &recipient_domain, FALSE);
3196 /* rfc821_domains = FALSE; << no longer needed */
3198 if (address == NULL)
3199 s = string_sprintf("501 %s", errmess);
3202 address_item *addr = deliver_make_addr(address, FALSE);
3203 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3204 -1, -1, NULL, NULL, NULL))
3207 s = string_sprintf("250 <%s> is deliverable", address);
3211 s = (addr->user_message != NULL)?
3212 string_sprintf("451 <%s> %s", address, addr->user_message) :
3213 string_sprintf("451 Cannot resolve <%s> at this time", address);
3217 s = (addr->user_message != NULL)?
3218 string_sprintf("550 <%s> %s", address, addr->user_message) :
3219 string_sprintf("550 <%s> is not deliverable", address);
3220 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3221 smtp_cmd_argument, host_and_ident(TRUE));
3226 smtp_printf("%s\r\n", s);
3232 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3234 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3237 BOOL save_log_testing_mode = log_testing_mode;
3238 address_test_mode = log_testing_mode = TRUE;
3239 (void) verify_address(deliver_make_addr(smtp_cmd_argument, FALSE),
3240 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3242 address_test_mode = FALSE;
3243 log_testing_mode = save_log_testing_mode; /* true for -bh */
3251 if (!tls_advertised)
3253 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3254 US"STARTTLS command used when not advertised");
3258 /* Apply an ACL check if one is defined */
3260 if (acl_smtp_starttls != NULL)
3262 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3266 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3271 /* RFC 2487 is not clear on when this command may be sent, though it
3272 does state that all information previously obtained from the client
3273 must be discarded if a TLS session is started. It seems reasonble to
3274 do an implied RSET when STARTTLS is received. */
3276 incomplete_transaction_log(US"STARTTLS");
3277 smtp_reset(reset_point);
3279 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3281 /* Attempt to start up a TLS session, and if successful, discard all
3282 knowledge that was obtained previously. At least, that's what the RFC says,
3283 and that's what happens by default. However, in order to work round YAEB,
3284 there is an option to remember the esmtp state. Sigh.
3286 We must allow for an extra EHLO command and an extra AUTH command after
3287 STARTTLS that don't add to the nonmail command count. */
3289 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3291 if (!tls_remember_esmtp)
3292 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3293 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3294 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3295 if (sender_helo_name != NULL)
3297 store_free(sender_helo_name);
3298 sender_helo_name = NULL;
3299 host_build_sender_fullhost(); /* Rebuild */
3300 set_process_info("handling incoming TLS connection from %s",
3301 host_and_ident(FALSE));
3303 received_protocol = (esmtp?
3304 protocols[pextend + pcrpted +
3305 ((sender_host_authenticated != NULL)? pauthed : 0)]
3307 protocols[pnormal + pcrpted])
3309 ((sender_host_address != NULL)? pnlocal : 0);
3311 sender_host_authenticated = NULL;
3312 authenticated_id = NULL;
3313 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3314 DEBUG(D_tls) debug_printf("TLS active\n");
3315 break; /* Successful STARTTLS */
3318 /* Some local configuration problem was discovered before actually trying
3319 to do a TLS handshake; give a temporary error. */
3321 else if (rc == DEFER)
3323 smtp_printf("454 TLS currently unavailable\r\n");
3327 /* Hard failure. Reject everything except QUIT or closed connection. One
3328 cause for failure is a nested STARTTLS, in which case tls_active remains
3329 set, but we must still reject all incoming commands. */
3331 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3334 switch(smtp_read_command(FALSE))
3337 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3338 smtp_get_connection_info());
3343 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3344 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3345 smtp_get_connection_info());
3350 smtp_printf("554 Security failure\r\n");
3359 /* The ACL for QUIT is provided for gathering statistical information or
3360 similar; it does not affect the response code, but it can supply a custom
3364 incomplete_transaction_log(US"QUIT");
3366 if (acl_smtp_quit != NULL)
3368 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit,&user_msg,&log_msg);
3370 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3373 else user_msg = NULL;
3375 if (user_msg == NULL)
3376 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3378 smtp_printf("221 %s\r\n", user_msg);
3385 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3386 smtp_get_connection_info());
3391 incomplete_transaction_log(US"RSET");
3392 smtp_reset(reset_point);
3394 smtp_printf("250 Reset OK\r\n");
3395 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3400 smtp_printf("250 OK\r\n");
3404 /* Show ETRN/EXPN/VRFY if there's
3405 an ACL for checking hosts; if actually used, a check will be done for
3409 smtp_printf("214-Commands supported:\r\n");
3413 Ustrcat(buffer, " AUTH");
3415 Ustrcat(buffer, " STARTTLS");
3417 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3418 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3419 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3420 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3421 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3422 smtp_printf("214%s\r\n", buffer);
3428 incomplete_transaction_log(US"connection lost");
3429 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3431 /* Don't log by default unless in the middle of a message, as some mailers
3432 just drop the call rather than sending QUIT, and it clutters up the logs.
3435 if (sender_address != NULL || recipients_count > 0)
3436 log_write(L_lost_incoming_connection,
3438 "unexpected %s while reading SMTP command from %s%s",
3439 sender_host_unknown? "EOF" : "disconnection",
3440 host_and_ident(FALSE), smtp_read_error);
3442 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3443 smtp_get_connection_info(), smtp_read_error);
3450 if (sender_address != NULL)
3452 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3453 US"ETRN is not permitted inside a transaction");
3457 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
3458 host_and_ident(FALSE));
3460 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
3463 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3467 /* Compute the serialization key for this command. */
3469 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_argument);
3471 /* If a command has been specified for running as a result of ETRN, we
3472 permit any argument to ETRN. If not, only the # standard form is permitted,
3473 since that is strictly the only kind of ETRN that can be implemented
3474 according to the RFC. */
3476 if (smtp_etrn_command != NULL)
3480 etrn_command = smtp_etrn_command;
3481 deliver_domain = smtp_cmd_argument;
3482 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3483 US"ETRN processing", &error);
3484 deliver_domain = NULL;
3487 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3489 smtp_printf("458 Internal failure\r\n");
3494 /* Else set up to call Exim with the -R option. */
3498 if (*smtp_cmd_argument++ != '#')
3500 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3501 US"argument must begin with #");
3504 etrn_command = US"exim -R";
3505 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3509 /* If we are host-testing, don't actually do anything. */
3515 debug_printf("ETRN command is: %s\n", etrn_command);
3516 debug_printf("ETRN command execution skipped\n");
3518 smtp_printf("250 OK\r\n");
3523 /* If ETRN queue runs are to be serialized, check the database to
3524 ensure one isn't already running. */
3526 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3528 smtp_printf("458 Already processing %s\r\n", smtp_cmd_argument);
3532 /* Fork a child process and run the command. We don't want to have to
3533 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3534 forking. It should be set that way anyway for external incoming SMTP,
3535 but we save and restore to be tidy. If serialization is required, we
3536 actually run the command in yet another process, so we can wait for it
3537 to complete and then remove the serialization lock. */
3539 oldsignal = signal(SIGCHLD, SIG_IGN);
3541 if ((pid = fork()) == 0)
3543 smtp_input = FALSE; /* This process is not associated with the */
3544 (void)fclose(smtp_in); /* SMTP call any more. */
3545 (void)fclose(smtp_out);
3547 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3549 /* If not serializing, do the exec right away. Otherwise, fork down
3550 into another process. */
3552 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3554 DEBUG(D_exec) debug_print_argv(argv);
3555 exim_nullstd(); /* Ensure std{in,out,err} exist */
3556 execv(CS argv[0], (char *const *)argv);
3557 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3558 etrn_command, strerror(errno));
3559 _exit(EXIT_FAILURE); /* paranoia */
3562 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3563 is, we are in the first subprocess, after forking again. All we can do
3564 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3565 complete, before removing the serialization. */
3568 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3569 "failed: %s", strerror(errno));
3573 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3575 (void)wait(&status);
3576 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3580 enq_end(etrn_serialize_key);
3581 _exit(EXIT_SUCCESS);
3584 /* Back in the top level SMTP process. Check that we started a subprocess
3585 and restore the signal state. */
3589 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3591 smtp_printf("458 Unable to fork process\r\n");
3592 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3594 else smtp_printf("250 OK\r\n");
3596 signal(SIGCHLD, oldsignal);
3601 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3602 US"unexpected argument data");
3606 /* This currently happens only for NULLs, but could be extended. */
3609 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3610 US"NULL character(s) present (shown as '?')");
3611 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3616 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3617 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3618 c = smtp_inend - smtp_inptr;
3619 if (c > 150) c = 150;
3621 incomplete_transaction_log(US"sync failure");
3622 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
3623 "(next input sent too soon: pipelining was%s advertised): "
3624 "rejected \"%s\" %s next input=\"%s\"",
3625 pipelining_advertised? "" : " not",
3626 smtp_cmd_buffer, host_and_ident(TRUE),
3627 string_printing(smtp_inptr));
3628 smtp_printf("554 SMTP synchronization error\r\n");
3629 done = 1; /* Pretend eof - drops connection */
3633 case TOO_MANY_NONMAIL_CMD:
3634 incomplete_transaction_log(US"too many non-mail commands");
3635 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3636 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
3637 smtp_cmd_argument - smtp_cmd_buffer, smtp_cmd_buffer);
3638 smtp_printf("554 Too many nonmail commands\r\n");
3639 done = 1; /* Pretend eof - drops connection */
3644 if (unknown_command_count++ >= smtp_max_unknown_commands)
3646 log_write(L_smtp_syntax_error, LOG_MAIN,
3647 "SMTP syntax error in \"%s\" %s %s",
3648 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
3649 US"unrecognized command");
3650 incomplete_transaction_log(US"unrecognized command");
3651 smtp_printf("500 Too many unrecognized commands\r\n");
3653 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3654 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3658 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3659 US"unrecognized command");
3663 /* This label is used by goto's inside loops that want to break out to
3664 the end of the command-processing loop. */
3667 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3668 last_was_rcpt = was_rcpt; /* protocol error handling */
3672 return done - 2; /* Convert yield values */
3675 /* End of smtp_in.c */