1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.40 2006/07/27 10:13:52 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 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1160 authentication settings from -oMaa to remain in force. */
1162 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1163 authenticated_by = NULL;
1166 tls_cipher = tls_peerdn = NULL;
1167 tls_advertised = FALSE;
1170 /* Reset ACL connection variables */
1172 for (i = 0; i < ACL_CVARS; i++) acl_var[i] = NULL;
1174 /* Allow for trailing 0 in the command buffer. */
1176 smtp_cmd_buffer = (uschar *)malloc(smtp_cmd_buffer_size + 1);
1177 if (smtp_cmd_buffer == NULL)
1178 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1179 "malloc() failed for SMTP command buffer");
1181 /* For batched input, the protocol setting can be overridden from the
1182 command line by a trusted caller. */
1184 if (smtp_batched_input)
1186 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1189 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1190 reset later if any of EHLO/AUTH/STARTTLS are received. */
1194 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1196 /* Set up the buffer for inputting using direct read() calls, and arrange to
1197 call the local functions instead of the standard C ones. */
1199 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1200 if (smtp_inbuffer == NULL)
1201 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1202 receive_getc = smtp_getc;
1203 receive_ungetc = smtp_ungetc;
1204 receive_feof = smtp_feof;
1205 receive_ferror = smtp_ferror;
1206 smtp_inptr = smtp_inend = smtp_inbuffer;
1207 smtp_had_eof = smtp_had_error = 0;
1209 /* Set up the message size limit; this may be host-specific */
1211 thismessage_size_limit = expand_string_integer(message_size_limit);
1212 if (thismessage_size_limit < 0)
1214 if (thismessage_size_limit == -1)
1215 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1216 "%s", expand_string_message);
1218 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1219 "%s", expand_string_message);
1220 smtp_closedown(US"Temporary local problem - please try later");
1224 /* When a message is input locally via the -bs or -bS options, sender_host_
1225 unknown is set unless -oMa was used to force an IP address, in which case it
1226 is checked like a real remote connection. When -bs is used from inetd, this
1227 flag is not set, causing the sending host to be checked. The code that deals
1228 with IP source routing (if configured) is never required for -bs or -bS and
1229 the flag sender_host_notsocket is used to suppress it.
1231 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1232 reserve for certain hosts and/or networks. */
1234 if (!sender_host_unknown)
1237 BOOL reserved_host = FALSE;
1239 /* Look up IP options (source routing info) on the socket if this is not an
1240 -oMa "host", and if any are found, log them and drop the connection.
1242 Linux (and others now, see below) is different to everyone else, so there
1243 has to be some conditional compilation here. Versions of Linux before 2.1.15
1244 used a structure whose name was "options". Somebody finally realized that
1245 this name was silly, and it got changed to "ip_options". I use the
1246 newer name here, but there is a fudge in the script that sets up os.h
1247 to define a macro in older Linux systems.
1249 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1250 glibc 2, which has chosen ip_opts for the structure name. This is now
1251 really a glibc thing rather than a Linux thing, so the condition name
1252 has been changed to reflect this. It is relevant also to GNU/Hurd.
1254 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1255 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1256 a special macro defined in the os.h file.
1258 Some DGUX versions on older hardware appear not to support IP options at
1259 all, so there is now a general macro which can be set to cut out this
1262 How to do this properly in IPv6 is not yet known. */
1264 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1266 #ifdef GLIBC_IP_OPTIONS
1267 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1272 #elif defined DARWIN_IP_OPTIONS
1278 if (!host_checking && !sender_host_notsocket)
1281 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1282 struct ip_options *ipopt = store_get(optlen);
1284 struct ip_opts ipoptblock;
1285 struct ip_opts *ipopt = &ipoptblock;
1286 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1288 struct ipoption ipoptblock;
1289 struct ipoption *ipopt = &ipoptblock;
1290 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1293 /* Occasional genuine failures of getsockopt() have been seen - for
1294 example, "reset by peer". Therefore, just log and give up on this
1295 call, unless the error is ENOPROTOOPT. This error is given by systems
1296 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1297 of writing. So for that error, carry on - we just can't do an IP options
1300 DEBUG(D_receive) debug_printf("checking for IP options\n");
1302 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1305 if (errno != ENOPROTOOPT)
1307 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1308 host_and_ident(FALSE), strerror(errno));
1309 smtp_printf("451 SMTP service not available\r\n");
1314 /* Deal with any IP options that are set. On the systems I have looked at,
1315 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1316 more logging data than will fit in big_buffer. Nevertheless, after somebody
1317 questioned this code, I've added in some paranoid checking. */
1319 else if (optlen > 0)
1321 uschar *p = big_buffer;
1322 uschar *pend = big_buffer + big_buffer_size;
1323 uschar *opt, *adptr;
1325 struct in_addr addr;
1328 uschar *optstart = (uschar *)(ipopt->__data);
1330 uschar *optstart = (uschar *)(ipopt->ip_opts);
1332 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1335 DEBUG(D_receive) debug_printf("IP options exist\n");
1337 Ustrcpy(p, "IP options on incoming call:");
1340 for (opt = optstart; opt != NULL &&
1341 opt < (uschar *)(ipopt) + optlen;)
1355 if (!string_format(p, pend-p, " %s [@%s",
1356 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1358 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1360 inet_ntoa(ipopt->ip_dst)))
1362 inet_ntoa(ipopt->ipopt_dst)))
1370 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1372 while (optcount-- > 0)
1374 memcpy(&addr, adptr, sizeof(addr));
1375 if (!string_format(p, pend - p - 1, "%s%s",
1376 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1382 adptr += sizeof(struct in_addr);
1391 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1394 for (i = 0; i < opt[1]; i++)
1396 sprintf(CS p, "%2.2x ", opt[i]);
1407 log_write(0, LOG_MAIN, "%s", big_buffer);
1409 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1411 log_write(0, LOG_MAIN|LOG_REJECT,
1412 "connection from %s refused (IP options)", host_and_ident(FALSE));
1414 smtp_printf("554 SMTP service not available\r\n");
1418 /* Length of options = 0 => there are no options */
1420 else DEBUG(D_receive) debug_printf("no IP options found\n");
1422 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1424 /* Set keep-alive in socket options. The option is on by default. This
1425 setting is an attempt to get rid of some hanging connections that stick in
1426 read() when the remote end (usually a dialup) goes away. */
1428 if (smtp_accept_keepalive && !sender_host_notsocket)
1429 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1431 /* If the current host matches host_lookup, set the name by doing a
1432 reverse lookup. On failure, sender_host_name will be NULL and
1433 host_lookup_failed will be TRUE. This may or may not be serious - optional
1436 if (verify_check_host(&host_lookup) == OK)
1438 (void)host_name_lookup();
1439 host_build_sender_fullhost();
1442 /* Delay this until we have the full name, if it is looked up. */
1444 set_process_info("handling incoming connection from %s",
1445 host_and_ident(FALSE));
1447 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1448 smtps port for use with older style SSL MTAs. */
1451 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1455 /* Test for explicit connection rejection */
1457 if (verify_check_host(&host_reject_connection) == OK)
1459 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1460 "from %s (host_reject_connection)", host_and_ident(FALSE));
1461 smtp_printf("554 SMTP service not available\r\n");
1465 /* Test with TCP Wrappers if so configured. There is a problem in that
1466 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1467 such as disks dying. In these cases, it is desirable to reject with a 4xx
1468 error instead of a 5xx error. There isn't a "right" way to detect such
1469 problems. The following kludge is used: errno is zeroed before calling
1470 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1471 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1474 #ifdef USE_TCP_WRAPPERS
1476 if (!hosts_ctl("exim",
1477 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1478 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1479 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1481 if (errno == 0 || errno == ENOENT)
1483 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1484 log_write(L_connection_reject,
1485 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1486 "(tcp wrappers)", host_and_ident(FALSE));
1487 smtp_printf("554 SMTP service not available\r\n");
1491 int save_errno = errno;
1492 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1493 "errno value %d\n", save_errno);
1494 log_write(L_connection_reject,
1495 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1496 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1497 smtp_printf("451 Temporary local problem - please try later\r\n");
1503 /* Check for reserved slots. Note that the count value doesn't include
1504 this process, as it gets upped in the parent process. */
1506 if (smtp_accept_max > 0 &&
1507 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1509 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1511 log_write(L_connection_reject,
1512 LOG_MAIN, "temporarily refused connection from %s: not in "
1513 "reserve list: connected=%d max=%d reserve=%d%s",
1514 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1515 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1516 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1517 "please try again later\r\n", smtp_active_hostname);
1520 reserved_host = TRUE;
1523 /* If a load level above which only messages from reserved hosts are
1524 accepted is set, check the load. For incoming calls via the daemon, the
1525 check is done in the superior process if there are no reserved hosts, to
1526 save a fork. In all cases, the load average will already be available
1527 in a global variable at this point. */
1529 if (smtp_load_reserve >= 0 &&
1530 load_average > smtp_load_reserve &&
1532 verify_check_host(&smtp_reserve_hosts) != OK)
1534 log_write(L_connection_reject,
1535 LOG_MAIN, "temporarily refused connection from %s: not in "
1536 "reserve list and load average = %.2f", host_and_ident(FALSE),
1537 (double)load_average/1000.0);
1538 smtp_printf("421 %s: Too much load; please try again later\r\n",
1539 smtp_active_hostname);
1543 /* Determine whether unqualified senders or recipients are permitted
1544 for this host. Unfortunately, we have to do this every time, in order to
1545 set the flags so that they can be inspected when considering qualifying
1546 addresses in the headers. For a site that permits no qualification, this
1547 won't take long, however. */
1549 allow_unqualified_sender =
1550 verify_check_host(&sender_unqualified_hosts) == OK;
1552 allow_unqualified_recipient =
1553 verify_check_host(&recipient_unqualified_hosts) == OK;
1555 /* Determine whether HELO/EHLO is required for this host. The requirement
1556 can be hard or soft. */
1558 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1560 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1562 /* Determine whether this hosts is permitted to send syntactic junk
1563 after a HELO or EHLO command. */
1565 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1568 /* For batch SMTP input we are now done. */
1570 if (smtp_batched_input) return TRUE;
1572 /* Run the ACL if it exists */
1574 if (acl_smtp_connect != NULL)
1577 uschar *user_msg, *log_msg;
1578 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1582 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1587 /* Output the initial message for a two-way SMTP connection. It may contain
1588 newlines, which then cause a multi-line response to be given. */
1590 s = expand_string(smtp_banner);
1592 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1593 "failed: %s", smtp_banner, expand_string_message);
1595 /* Remove any terminating newlines; might as well remove trailing space too */
1598 while (p > s && isspace(p[-1])) p--;
1601 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1602 is all contained in a single IP packet. The original code wrote out the
1603 greeting using several calls to fprint/fputc, and on busy servers this could
1604 cause it to be split over more than one packet - which caused CC:Mail to fall
1605 over when it got the second part of the greeting after sending its first
1606 command. Sigh. To try to avoid this, build the complete greeting message
1607 first, and output it in one fell swoop. This gives a better chance of it
1608 ending up as a single packet. */
1610 ss = store_get(size);
1614 do /* At least once, in case we have an empty string */
1617 uschar *linebreak = Ustrchr(p, '\n');
1618 if (linebreak == NULL)
1621 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1625 len = linebreak - p;
1626 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1628 ss = string_cat(ss, &size, &ptr, p, len);
1629 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1631 if (linebreak != NULL) p++;
1635 ss[ptr] = 0; /* string_cat leaves room for this */
1637 /* Before we write the banner, check that there is no input pending, unless
1638 this synchronisation check is disabled. */
1640 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1643 struct timeval tzero;
1647 FD_SET(fileno(smtp_in), &fds);
1648 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1651 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1654 if (rc > 150) rc = 150;
1655 smtp_inbuffer[rc] = 0;
1656 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1657 "synchronization error (input sent without waiting for greeting): "
1658 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1659 string_printing(smtp_inbuffer));
1660 smtp_printf("554 SMTP synchronization error\r\n");
1666 /* Now output the banner */
1668 smtp_printf("%s", ss);
1676 /*************************************************
1677 * Handle SMTP syntax and protocol errors *
1678 *************************************************/
1680 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1681 to do so. Then transmit the error response. The return value depends on the
1682 number of syntax and protocol errors in this SMTP session.
1685 type error type, given as a log flag bit
1686 code response code; <= 0 means don't send a response
1687 data data to reflect in the response (can be NULL)
1688 errmess the error message
1690 Returns: -1 limit of syntax/protocol errors NOT exceeded
1691 +1 limit of syntax/protocol errors IS exceeded
1693 These values fit in with the values of the "done" variable in the main
1694 processing loop in smtp_setup_msg(). */
1697 synprot_error(int type, int code, uschar *data, uschar *errmess)
1701 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1702 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1703 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1705 if (++synprot_error_count > smtp_max_synprot_errors)
1708 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1709 "syntax or protocol errors (last command was \"%s\")",
1710 host_and_ident(FALSE), smtp_cmd_buffer);
1715 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1716 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1718 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1727 /*************************************************
1728 * Log incomplete transactions *
1729 *************************************************/
1731 /* This function is called after a transaction has been aborted by RSET, QUIT,
1732 connection drops or other errors. It logs the envelope information received
1733 so far in order to preserve address verification attempts.
1735 Argument: string to indicate what aborted the transaction
1740 incomplete_transaction_log(uschar *what)
1742 if (sender_address == NULL || /* No transaction in progress */
1743 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1746 /* Build list of recipients for logging */
1748 if (recipients_count > 0)
1751 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1752 for (i = 0; i < recipients_count; i++)
1753 raw_recipients[i] = recipients_list[i].address;
1754 raw_recipients_count = recipients_count;
1757 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1758 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1764 /*************************************************
1765 * Send SMTP response, possibly multiline *
1766 *************************************************/
1768 /* There are, it seems, broken clients out there that cannot handle multiline
1769 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1770 output nothing for non-final calls, and only the first line for anything else.
1773 code SMTP code, may involve extended status codes
1774 codelen length of smtp code; uf > 3 there's an ESC
1775 final FALSE if the last line isn't the final line
1776 msg message text, possibly containing newlines
1782 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
1787 if (!final && no_multiline_responses) return;
1792 esclen = codelen - 4;
1797 uschar *nl = Ustrchr(msg, '\n');
1800 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
1803 else if (nl[1] == 0 || no_multiline_responses)
1805 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
1806 (int)(nl - msg), msg);
1811 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
1813 while (isspace(*msg)) msg++;
1821 /*************************************************
1822 * Handle an ACL failure *
1823 *************************************************/
1825 /* This function is called when acl_check() fails. As well as calls from within
1826 this module, it is called from receive.c for an ACL after DATA. It sorts out
1827 logging the incident, and sets up the error response. A message containing
1828 newlines is turned into a multiline SMTP response, but for logging, only the
1831 There's a table of default permanent failure response codes to use in
1832 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
1833 defaults disabled in Exim. However, discussion in connection with RFC 821bis
1834 (aka RFC 2821) has concluded that the response should be 252 in the disabled
1835 state, because there are broken clients that try VRFY before RCPT. A 5xx
1836 response should be given only when the address is positively known to be
1837 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
1840 From Exim 4.63, it is possible to override the response code details by
1841 providing a suitable response code string at the start of the message provided
1842 in user_msg. The code's first digit is checked for validity.
1845 where where the ACL was called from
1847 user_msg a message that can be included in an SMTP response
1848 log_msg a message for logging
1850 Returns: 0 in most cases
1851 2 if the failure code was FAIL_DROP, in which case the
1852 SMTP connection should be dropped (this value fits with the
1853 "done" variable in smtp_setup_msg() below)
1857 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1859 BOOL drop = rc == FAIL_DROP;
1864 uschar *sender_info = US"";
1866 #ifdef WITH_CONTENT_SCAN
1867 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1869 (where == ACL_WHERE_PREDATA)? US"DATA" :
1870 (where == ACL_WHERE_DATA)? US"after DATA" :
1871 (smtp_cmd_argument == NULL)?
1872 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
1873 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_argument);
1875 if (drop) rc = FAIL;
1877 /* Set the default SMTP code */
1879 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
1881 /* Check a user message for starting with a response code and optionally an
1882 extended status code. If found, check that the first digit is valid, and if so,
1883 use it instead of the default code. */
1885 if (user_msg != NULL)
1887 int n = pcre_exec(regex_smtp_code, NULL, CS user_msg, Ustrlen(user_msg), 0,
1888 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
1891 if (user_msg[0] != smtp_code[0])
1893 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
1894 "incorrect digit (expected %c) in \"%s\"", smtp_code[0], user_msg);
1896 /* If log_msg == user_msg (the default set in acl.c if no log message is
1897 specified, we must adjust the log message to show the code that is
1898 actually going to be used. */
1900 if (log_msg == user_msg)
1901 log_msg = string_sprintf("%s %s", smtp_code, log_msg + ovector[1]);
1905 smtp_code = user_msg;
1906 codelen = ovector[1]; /* Includes final space */
1908 user_msg += ovector[1]; /* Chop the code off the message */
1912 /* We used to have sender_address here; however, there was a bug that was not
1913 updating sender_address after a rewrite during a verify. When this bug was
1914 fixed, sender_address at this point became the rewritten address. I'm not sure
1915 this is what should be logged, so I've changed to logging the unrewritten
1916 address to retain backward compatibility. */
1918 #ifndef WITH_CONTENT_SCAN
1919 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1921 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1924 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1925 sender_address_unrewritten : sender_address);
1928 /* If there's been a sender verification failure with a specific message, and
1929 we have not sent a response about it yet, do so now, as a preliminary line for
1930 failures, but not defers. However, always log it for defer, and log it for fail
1931 unless the sender_verify_fail log selector has been turned off. */
1933 if (sender_verified_failed != NULL &&
1934 !testflag(sender_verified_failed, af_sverify_told))
1936 setflag(sender_verified_failed, af_sverify_told);
1938 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
1939 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1940 host_and_ident(TRUE),
1941 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
1942 sender_verified_failed->address,
1943 (sender_verified_failed->message == NULL)? US"" :
1944 string_sprintf(": %s", sender_verified_failed->message));
1946 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1947 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
1948 testflag(sender_verified_failed, af_verify_pmfail)?
1949 "Postmaster verification failed while checking <%s>\n%s\n"
1950 "Several RFCs state that you are required to have a postmaster\n"
1951 "mailbox for each mail domain. This host does not accept mail\n"
1952 "from domains whose servers reject the postmaster address."
1954 testflag(sender_verified_failed, af_verify_nsfail)?
1955 "Callback setup failed while verifying <%s>\n%s\n"
1956 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1957 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1958 "RFC requirements, and stops you from receiving standard bounce\n"
1959 "messages. This host does not accept mail from domains whose servers\n"
1962 "Verification failed for <%s>\n%s",
1963 sender_verified_failed->address,
1964 sender_verified_failed->user_message));
1967 /* Sort out text for logging */
1969 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1970 lognl = Ustrchr(log_msg, '\n');
1971 if (lognl != NULL) *lognl = 0;
1973 /* Send permanent failure response to the command, but the code used isn't
1974 always a 5xx one - see comments at the start of this function. If the original
1975 rc was FAIL_DROP we drop the connection and yield 2. */
1977 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
1978 US"Administrative prohibition" : user_msg);
1980 /* Send temporary failure response to the command. Don't give any details,
1981 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1982 verb, and for a header verify when smtp_return_error_details is set.
1984 This conditional logic is all somewhat of a mess because of the odd
1985 interactions between temp_details and return_error_details. One day it should
1986 be re-implemented in a tidier fashion. */
1990 if (acl_temp_details && user_msg != NULL)
1992 if (smtp_return_error_details &&
1993 sender_verified_failed != NULL &&
1994 sender_verified_failed->message != NULL)
1996 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
1998 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2001 smtp_respond(smtp_code, codelen, TRUE,
2002 US"Temporary local problem - please try later");
2005 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
2006 Otherwise, log why it is closing if required and return 2. */
2008 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
2009 host_and_ident(TRUE),
2010 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2012 if (!drop) return 0;
2014 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2015 smtp_get_connection_info());
2022 /*************************************************
2023 * Verify HELO argument *
2024 *************************************************/
2026 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2027 matched. It is also called from ACL processing if verify = helo is used and
2028 verification was not previously tried (i.e. helo_try_verify_hosts was not
2029 matched). The result of its processing is to set helo_verified and
2030 helo_verify_failed. These variables should both be FALSE for this function to
2033 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2034 for IPv6 ::ffff: literals.
2037 Returns: TRUE if testing was completed;
2038 FALSE on a temporary failure
2042 smtp_verify_helo(void)
2046 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2049 if (sender_helo_name == NULL)
2051 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2054 else if (sender_helo_name[0] == '[')
2056 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2057 Ustrlen(sender_host_address)) == 0;
2062 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2063 helo_verified = Ustrncmp(sender_helo_name + 1,
2064 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2069 { if (helo_verified) debug_printf("matched host address\n"); }
2072 /* Do a reverse lookup if one hasn't already given a positive or negative
2073 response. If that fails, or the name doesn't match, try checking with a forward
2078 if (sender_host_name == NULL && !host_lookup_failed)
2079 yield = host_name_lookup() != DEFER;
2081 /* If a host name is known, check it and all its aliases. */
2083 if (sender_host_name != NULL)
2085 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2089 HDEBUG(D_receive) debug_printf("matched host name\n");
2093 uschar **aliases = sender_host_aliases;
2094 while (*aliases != NULL)
2096 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2097 if (helo_verified) break;
2102 debug_printf("matched alias %s\n", *(--aliases));
2107 /* Final attempt: try a forward lookup of the helo name */
2113 h.name = sender_helo_name;
2117 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2119 rc = host_find_byname(&h, NULL, NULL, TRUE);
2120 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2125 if (Ustrcmp(hh->address, sender_host_address) == 0)
2127 helo_verified = TRUE;
2129 debug_printf("IP address for %s matches calling address\n",
2139 if (!helo_verified) helo_verify_failed = FALSE; /* We've tried ... */
2146 /*************************************************
2147 * Initialize for SMTP incoming message *
2148 *************************************************/
2150 /* This function conducts the initial dialogue at the start of an incoming SMTP
2151 message, and builds a list of recipients. However, if the incoming message
2152 is part of a batch (-bS option) a separate function is called since it would
2153 be messy having tests splattered about all over this function. This function
2154 therefore handles the case where interaction is occurring. The input and output
2155 files are set up in smtp_in and smtp_out.
2157 The global recipients_list is set to point to a vector of recipient_item
2158 blocks, whose number is given by recipients_count. This is extended by the
2159 receive_add_recipient() function. The global variable sender_address is set to
2160 the sender's address. The yield is +1 if a message has been successfully
2161 started, 0 if a QUIT command was encountered or the connection was refused from
2162 the particular host, or -1 if the connection was lost.
2166 Returns: > 0 message successfully started (reached DATA)
2167 = 0 QUIT read or end of file reached or call refused
2172 smtp_setup_msg(void)
2175 BOOL toomany = FALSE;
2176 BOOL discarded = FALSE;
2177 BOOL last_was_rej_mail = FALSE;
2178 BOOL last_was_rcpt = FALSE;
2179 void *reset_point = store_get(0);
2181 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2183 /* Reset for start of new message. We allow one RSET not to be counted as a
2184 nonmail command, for those MTAs that insist on sending it between every
2185 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2186 TLS between messages (an Exim client may do this if it has messages queued up
2187 for the host). Note: we do NOT reset AUTH at this point. */
2189 smtp_reset(reset_point);
2190 message_ended = END_NOTSTARTED;
2192 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2193 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2194 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2196 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2199 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2201 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2203 /* Batched SMTP is handled in a different function. */
2205 if (smtp_batched_input) return smtp_setup_batch_msg();
2207 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2208 value. The values are 2 larger than the required yield of the function. */
2213 uschar *etrn_command;
2214 uschar *etrn_serialize_key;
2216 uschar *user_msg, *log_msg;
2217 uschar *recipient = NULL;
2218 uschar *hello = NULL;
2219 uschar *set_id = NULL;
2221 BOOL was_rej_mail = FALSE;
2222 BOOL was_rcpt = FALSE;
2223 void (*oldsignal)(int);
2225 int start, end, sender_domain, recipient_domain;
2230 switch(smtp_read_command(TRUE))
2232 /* The AUTH command is not permitted to occur inside a transaction, and may
2233 occur successfully only once per connection. Actually, that isn't quite
2234 true. When TLS is started, all previous information about a connection must
2235 be discarded, so a new AUTH is permitted at that time.
2237 AUTH may only be used when it has been advertised. However, it seems that
2238 there are clients that send AUTH when it hasn't been advertised, some of
2239 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2240 So there's a get-out that allows this to happen.
2242 AUTH is initially labelled as a "nonmail command" so that one occurrence
2243 doesn't get counted. We change the label here so that multiple failing
2244 AUTHS will eventually hit the nonmail threshold. */
2247 authentication_failed = TRUE;
2248 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2250 if (!auth_advertised && !allow_auth_unadvertised)
2252 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2253 US"AUTH command used when not advertised");
2256 if (sender_host_authenticated != NULL)
2258 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2259 US"already authenticated");
2262 if (sender_address != NULL)
2264 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2265 US"not permitted in mail transaction");
2271 if (acl_smtp_auth != NULL)
2273 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2276 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2281 /* Find the name of the requested authentication mechanism. */
2283 s = smtp_cmd_argument;
2284 while ((c = *smtp_cmd_argument) != 0 && !isspace(c))
2286 if (!isalnum(c) && c != '-' && c != '_')
2288 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2289 US"invalid character in authentication mechanism name");
2292 smtp_cmd_argument++;
2295 /* If not at the end of the line, we must be at white space. Terminate the
2296 name and move the pointer on to any data that may be present. */
2298 if (*smtp_cmd_argument != 0)
2300 *smtp_cmd_argument++ = 0;
2301 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
2304 /* Search for an authentication mechanism which is configured for use
2305 as a server and which has been advertised (unless, sigh, allow_auth_
2306 unadvertised is set). */
2308 for (au = auths; au != NULL; au = au->next)
2310 if (strcmpic(s, au->public_name) == 0 && au->server &&
2311 (au->advertised || allow_auth_unadvertised)) break;
2316 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2317 string_sprintf("%s authentication mechanism not supported", s));
2321 /* Run the checking code, passing the remainder of the command line as
2322 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2323 it as the only set numerical variable. The authenticator may set $auth<n>
2324 and also set other numeric variables. The $auth<n> variables are preferred
2325 nowadays; the numerical variables remain for backwards compatibility.
2327 Afterwards, have a go at expanding the set_id string, even if
2328 authentication failed - for bad passwords it can be useful to log the
2329 userid. On success, require set_id to expand and exist, and put it in
2330 authenticated_id. Save this in permanent store, as the working store gets
2331 reset at HELO, RSET, etc. */
2333 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2335 expand_nlength[0] = 0; /* $0 contains nothing */
2337 c = (au->info->servercode)(au, smtp_cmd_argument);
2338 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2339 expand_nmax = -1; /* Reset numeric variables */
2340 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2342 /* The value of authenticated_id is stored in the spool file and printed in
2343 log lines. It must not contain binary zeros or newline characters. In
2344 normal use, it never will, but when playing around or testing, this error
2345 can (did) happen. To guard against this, ensure that the id contains only
2346 printing characters. */
2348 if (set_id != NULL) set_id = string_printing(set_id);
2350 /* For the non-OK cases, set up additional logging data if set_id
2355 if (set_id != NULL && *set_id != 0)
2356 set_id = string_sprintf(" (set_id=%s)", set_id);
2360 /* Switch on the result */
2365 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2367 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2368 sender_host_authenticated = au->name;
2369 authentication_failed = FALSE;
2371 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2372 ((sender_host_address != NULL)? pnlocal : 0);
2373 s = ss = US"235 Authentication succeeded";
2374 authenticated_by = au;
2378 /* Authentication succeeded, but we failed to expand the set_id string.
2379 Treat this as a temporary error. */
2381 auth_defer_msg = expand_string_message;
2385 s = string_sprintf("435 Unable to authenticate at present%s",
2386 auth_defer_user_msg);
2387 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2388 set_id, auth_defer_msg);
2392 s = ss = US"501 Invalid base64 data";
2396 s = ss = US"501 Authentication cancelled";
2400 s = ss = US"553 Initial data not expected";
2404 s = US"535 Incorrect authentication data";
2405 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2409 s = US"435 Internal error";
2410 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2411 "check", set_id, c);
2415 smtp_printf("%s\r\n", s);
2417 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2418 au->name, host_and_ident(FALSE), ss);
2420 break; /* AUTH_CMD */
2422 /* The HELO/EHLO commands are permitted to appear in the middle of a
2423 session as well as at the beginning. They have the effect of a reset in
2424 addition to their other functions. Their absence at the start cannot be
2425 taken to be an error.
2429 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2430 or 502 failure replies MUST be returned as appropriate. The SMTP
2431 server MUST stay in the same state after transmitting these replies
2432 that it was in before the EHLO was received.
2434 Therefore, we do not do the reset until after checking the command for
2435 acceptability. This change was made for Exim release 4.11. Previously
2436 it did the reset first. */
2447 HELO_EHLO: /* Common code for HELO and EHLO */
2448 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2449 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2451 /* Reject the HELO if its argument was invalid or non-existent. A
2452 successful check causes the argument to be saved in malloc store. */
2454 if (!check_helo(smtp_cmd_argument))
2456 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2458 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2459 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2460 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2461 string_printing(smtp_cmd_argument));
2463 if (++synprot_error_count > smtp_max_synprot_errors)
2465 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2466 "syntax or protocol errors (last command was \"%s\")",
2467 host_and_ident(FALSE), smtp_cmd_buffer);
2474 /* If sender_host_unknown is true, we have got here via the -bs interface,
2475 not called from inetd. Otherwise, we are running an IP connection and the
2476 host address will be set. If the helo name is the primary name of this
2477 host and we haven't done a reverse lookup, force one now. If helo_required
2478 is set, ensure that the HELO name matches the actual host. If helo_verify
2479 is set, do the same check, but softly. */
2481 if (!sender_host_unknown)
2483 BOOL old_helo_verified = helo_verified;
2484 uschar *p = smtp_cmd_argument;
2486 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2489 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2490 because otherwise the log can be confusing. */
2492 if (sender_host_name == NULL &&
2493 (deliver_domain = sender_helo_name, /* set $domain */
2494 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2495 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2496 (void)host_name_lookup();
2498 /* Rebuild the fullhost info to include the HELO name (and the real name
2499 if it was looked up.) */
2501 host_build_sender_fullhost(); /* Rebuild */
2502 set_process_info("handling%s incoming connection from %s",
2503 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2505 /* Verify if configured. This doesn't give much security, but it does
2506 make some people happy to be able to do it. If helo_required is set,
2507 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2508 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2509 now obsolescent, since the verification can now be requested selectively
2512 helo_verified = helo_verify_failed = FALSE;
2513 if (helo_required || helo_verify)
2515 BOOL tempfail = !smtp_verify_helo();
2520 smtp_printf("%d %s argument does not match calling host\r\n",
2521 tempfail? 451 : 550, hello);
2522 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2523 tempfail? "temporarily " : "",
2524 hello, sender_helo_name, host_and_ident(FALSE));
2525 helo_verified = old_helo_verified;
2526 break; /* End of HELO/EHLO processing */
2528 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2529 "helo_try_verify_hosts\n", hello);
2534 #ifdef EXPERIMENTAL_SPF
2535 /* set up SPF context */
2536 spf_init(sender_helo_name, sender_host_address);
2539 /* Apply an ACL check if one is defined */
2541 if (acl_smtp_helo != NULL)
2543 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2546 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2547 sender_helo_name = NULL;
2548 host_build_sender_fullhost(); /* Rebuild */
2553 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2554 abandoning any previous message. */
2556 received_protocol = (esmtp?
2558 ((sender_host_authenticated != NULL)? pauthed : 0) +
2559 ((tls_active >= 0)? pcrpted : 0)]
2561 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2563 ((sender_host_address != NULL)? pnlocal : 0);
2565 smtp_reset(reset_point);
2568 /* Generate an OK reply, including the ident if present, and also
2569 the IP address if present. Reflecting back the ident is intended
2570 as a deterrent to mail forgers. For maximum efficiency, and also
2571 because some broken systems expect each response to be in a single
2572 packet, arrange that it is sent in one write(). */
2574 auth_advertised = FALSE;
2575 pipelining_advertised = FALSE;
2577 tls_advertised = FALSE;
2580 s = string_sprintf("250 %s Hello %s%s%s",
2581 smtp_active_hostname,
2582 (sender_ident == NULL)? US"" : sender_ident,
2583 (sender_ident == NULL)? US"" : US" at ",
2584 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2589 if (sender_host_address != NULL)
2591 s = string_cat(s, &size, &ptr, US" [", 2);
2592 s = string_cat(s, &size, &ptr, sender_host_address,
2593 Ustrlen(sender_host_address));
2594 s = string_cat(s, &size, &ptr, US"]", 1);
2597 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2599 /* If we received EHLO, we must create a multiline response which includes
2600 the functions supported. */
2606 /* I'm not entirely happy with this, as an MTA is supposed to check
2607 that it has enough room to accept a message of maximum size before
2608 it sends this. However, there seems little point in not sending it.
2609 The actual size check happens later at MAIL FROM time. By postponing it
2610 till then, VRFY and EXPN can be used after EHLO when space is short. */
2612 if (thismessage_size_limit > 0)
2614 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2615 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2619 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2622 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2623 clean; if it has an 8-bit character in its hand, it just sends it. It
2624 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2625 However, some users want this option simply in order to stop MUAs
2626 mangling messages that contain top-bit-set characters. It is therefore
2627 provided as an option. */
2629 if (accept_8bitmime)
2630 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2632 /* Advertise ETRN if there's an ACL checking whether a host is
2633 permitted to issue it; a check is made when any host actually tries. */
2635 if (acl_smtp_etrn != NULL)
2637 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2640 /* Advertise EXPN if there's an ACL checking whether a host is
2641 permitted to issue it; a check is made when any host actually tries. */
2643 if (acl_smtp_expn != NULL)
2645 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2648 /* Exim is quite happy with pipelining, so let the other end know that
2649 it is safe to use it, unless advertising is disabled. */
2651 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2653 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2654 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2655 pipelining_advertised = TRUE;
2658 /* If any server authentication mechanisms are configured, advertise
2659 them if the current host is in auth_advertise_hosts. The problem with
2660 advertising always is that some clients then require users to
2661 authenticate (and aren't configurable otherwise) even though it may not
2662 be necessary (e.g. if the host is in host_accept_relay).
2664 RFC 2222 states that SASL mechanism names contain only upper case
2665 letters, so output the names in upper case, though we actually recognize
2666 them in either case in the AUTH command. */
2670 if (verify_check_host(&auth_advertise_hosts) == OK)
2674 for (au = auths; au != NULL; au = au->next)
2676 if (au->server && (au->advertise_condition == NULL ||
2677 expand_check_condition(au->advertise_condition, au->name,
2678 US"authenticator")))
2683 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2685 auth_advertised = TRUE;
2688 s = string_cat(s, &size, &ptr, US" ", 1);
2689 s = string_cat(s, &size, &ptr, au->public_name,
2690 Ustrlen(au->public_name));
2691 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2692 au->advertised = TRUE;
2694 else au->advertised = FALSE;
2696 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2700 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2701 if it has been included in the binary, and the host matches
2702 tls_advertise_hosts. We must *not* advertise if we are already in a
2703 secure connection. */
2706 if (tls_active < 0 &&
2707 verify_check_host(&tls_advertise_hosts) != FAIL)
2709 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2710 tls_advertised = TRUE;
2714 /* Finish off the multiline reply with one that is always available. */
2716 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2719 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2725 if (tls_active >= 0) (void)tls_write(s, ptr); else
2728 (void)fwrite(s, 1, ptr, smtp_out);
2732 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
2733 memmove(cr, cr + 1, (ptr--) - (cr - s));
2734 debug_printf("SMTP>> %s", s);
2737 break; /* HELO/EHLO */
2740 /* The MAIL command requires an address as an operand. All we do
2741 here is to parse it for syntactic correctness. The form "<>" is
2742 a special case which converts into an empty string. The start/end
2743 pointers in the original are not used further for this address, as
2744 it is the canonical extracted address which is all that is kept. */
2747 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2748 was_rej_mail = TRUE; /* Reset if accepted */
2750 if (helo_required && !helo_seen)
2752 smtp_printf("503 HELO or EHLO required\r\n");
2753 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2754 "HELO/EHLO given", host_and_ident(FALSE));
2758 if (sender_address != NULL)
2760 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2761 US"sender already given");
2765 if (smtp_cmd_argument[0] == 0)
2767 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2768 US"MAIL must have an address operand");
2772 /* Check to see if the limit for messages per connection would be
2773 exceeded by accepting further messages. */
2775 if (smtp_accept_max_per_connection > 0 &&
2776 smtp_mailcmd_count > smtp_accept_max_per_connection)
2778 smtp_printf("421 too many messages in this connection\r\n");
2779 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2780 "messages in one connection", host_and_ident(TRUE));
2784 /* Reset for start of message - even if this is going to fail, we
2785 obviously need to throw away any previous data. */
2787 smtp_reset(reset_point);
2789 sender_data = recipient_data = NULL;
2791 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2795 uschar *name, *value, *end;
2796 unsigned long int size;
2798 if (!extract_option(&name, &value)) break;
2800 /* Handle SIZE= by reading the value. We don't do the check till later,
2801 in order to be able to log the sender address on failure. */
2803 if (strcmpic(name, US"SIZE") == 0 &&
2804 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2806 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2808 message_size = (int)size;
2811 /* If this session was initiated with EHLO and accept_8bitmime is set,
2812 Exim will have indicated that it supports the BODY=8BITMIME option. In
2813 fact, it does not support this according to the RFCs, in that it does not
2814 take any special action for forwarding messages containing 8-bit
2815 characters. That is why accept_8bitmime is not the default setting, but
2816 some sites want the action that is provided. We recognize both "8BITMIME"
2817 and "7BIT" as body types, but take no action. */
2819 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2820 (strcmpic(value, US"8BITMIME") == 0 ||
2821 strcmpic(value, US"7BIT") == 0)) {}
2823 /* Handle the AUTH extension. If the value given is not "<>" and either
2824 the ACL says "yes" or there is no ACL but the sending host is
2825 authenticated, we set it up as the authenticated sender. However, if the
2826 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2827 the condition is met. The value of AUTH is an xtext, which means that +,
2828 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2831 else if (strcmpic(name, US"AUTH") == 0)
2833 if (Ustrcmp(value, "<>") != 0)
2838 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2840 /* Put back terminator overrides for error message */
2843 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2844 US"invalid data for AUTH");
2848 if (acl_smtp_mailauth == NULL)
2850 ignore_msg = US"client not authenticated";
2851 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2855 ignore_msg = US"rejected by ACL";
2856 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2857 &user_msg, &log_msg);
2863 if (authenticated_by == NULL ||
2864 authenticated_by->mail_auth_condition == NULL ||
2865 expand_check_condition(authenticated_by->mail_auth_condition,
2866 authenticated_by->name, US"authenticator"))
2867 break; /* Accept the AUTH */
2869 ignore_msg = US"server_mail_auth_condition failed";
2870 if (authenticated_id != NULL)
2871 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2872 ignore_msg, authenticated_id);
2877 authenticated_sender = NULL;
2878 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2879 value, host_and_ident(TRUE), ignore_msg);
2882 /* Should only get DEFER or ERROR here. Put back terminator
2883 overrides for error message */
2888 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2895 /* Unknown option. Stick back the terminator characters and break
2896 the loop. An error for a malformed address will occur. */
2906 /* If we have passed the threshold for rate limiting, apply the current
2907 delay, and update it for next time, provided this is a limited host. */
2909 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2910 verify_check_host(&smtp_ratelimit_hosts) == OK)
2912 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2913 smtp_delay_mail/1000.0);
2914 millisleep((int)smtp_delay_mail);
2915 smtp_delay_mail *= smtp_rlm_factor;
2916 if (smtp_delay_mail > (double)smtp_rlm_limit)
2917 smtp_delay_mail = (double)smtp_rlm_limit;
2920 /* Now extract the address, first applying any SMTP-time rewriting. The
2921 TRUE flag allows "<>" as a sender address. */
2923 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2924 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
2925 global_rewrite_rules) : smtp_cmd_argument;
2927 /* rfc821_domains = TRUE; << no longer needed */
2929 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2931 /* rfc821_domains = FALSE; << no longer needed */
2933 if (raw_sender == NULL)
2935 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
2939 sender_address = raw_sender;
2941 /* If there is a configured size limit for mail, check that this message
2942 doesn't exceed it. The check is postponed to this point so that the sender
2945 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2947 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2948 log_write(L_size_reject,
2949 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2950 "message too big: size%s=%d max=%d",
2952 host_and_ident(TRUE),
2953 (message_size == INT_MAX)? ">" : "",
2955 thismessage_size_limit);
2956 sender_address = NULL;
2960 /* Check there is enough space on the disk unless configured not to.
2961 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2962 plus the current message - i.e. we accept the message only if it won't
2963 reduce the space below the threshold. Add 5000 to the size to allow for
2964 overheads such as the Received: line and storing of recipients, etc.
2965 By putting the check here, even when SIZE is not given, it allow VRFY
2966 and EXPN etc. to be used when space is short. */
2968 if (!receive_check_fs(
2969 (smtp_check_spool_space && message_size >= 0)?
2970 message_size + 5000 : 0))
2972 smtp_printf("452 Space shortage, please try later\r\n");
2973 sender_address = NULL;
2977 /* If sender_address is unqualified, reject it, unless this is a locally
2978 generated message, or the sending host or net is permitted to send
2979 unqualified addresses - typically local machines behaving as MUAs -
2980 in which case just qualify the address. The flag is set above at the start
2981 of the SMTP connection. */
2983 if (sender_domain == 0 && sender_address[0] != 0)
2985 if (allow_unqualified_sender)
2987 sender_domain = Ustrlen(sender_address) + 1;
2988 sender_address = rewrite_address_qualify(sender_address, FALSE);
2989 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2994 smtp_printf("501 %s: sender address must contain a domain\r\n",
2996 log_write(L_smtp_syntax_error,
2997 LOG_MAIN|LOG_REJECT,
2998 "unqualified sender rejected: <%s> %s%s",
3000 host_and_ident(TRUE),
3002 sender_address = NULL;
3007 /* Apply an ACL check if one is defined, before responding */
3009 rc = (acl_smtp_mail == NULL)? OK :
3010 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3012 if (rc == OK || rc == DISCARD)
3014 smtp_printf("250 OK\r\n");
3015 smtp_delay_rcpt = smtp_rlr_base;
3016 recipients_discarded = (rc == DISCARD);
3017 was_rej_mail = FALSE;
3022 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3023 sender_address = NULL;
3028 /* The RCPT command requires an address as an operand. All we do
3029 here is to parse it for syntactic correctness. There may be any number
3030 of RCPT commands, specifying multiple senders. We build them all into
3031 a data structure that is in argc/argv format. The start/end values
3032 given by parse_extract_address are not used, as we keep only the
3033 extracted address. */
3039 /* There must be a sender address; if the sender was rejected and
3040 pipelining was advertised, we assume the client was pipelining, and do not
3041 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3042 get the same treatment. */
3044 if (sender_address == NULL)
3046 if (pipelining_advertised && last_was_rej_mail)
3048 smtp_printf("503 sender not yet given\r\n");
3049 was_rej_mail = TRUE;
3053 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3054 US"sender not yet given");
3055 was_rcpt = FALSE; /* Not a valid RCPT */
3061 /* Check for an operand */
3063 if (smtp_cmd_argument[0] == 0)
3065 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3066 US"RCPT must have an address operand");
3071 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3072 as a recipient address */
3074 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3075 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
3076 global_rewrite_rules) : smtp_cmd_argument;
3078 /* rfc821_domains = TRUE; << no longer needed */
3079 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3080 &recipient_domain, FALSE);
3081 /* rfc821_domains = FALSE; << no longer needed */
3083 if (recipient == NULL)
3085 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
3090 /* If the recipient address is unqualified, reject it, unless this is a
3091 locally generated message. However, unqualified addresses are permitted
3092 from a configured list of hosts and nets - typically when behaving as
3093 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3094 really. The flag is set at the start of the SMTP connection.
3096 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3097 assumed this meant "reserved local part", but the revision of RFC 821 and
3098 friends now makes it absolutely clear that it means *mailbox*. Consequently
3099 we must always qualify this address, regardless. */
3101 if (recipient_domain == 0)
3103 if (allow_unqualified_recipient ||
3104 strcmpic(recipient, US"postmaster") == 0)
3106 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3108 recipient_domain = Ustrlen(recipient) + 1;
3109 recipient = rewrite_address_qualify(recipient, TRUE);
3114 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3116 log_write(L_smtp_syntax_error,
3117 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3118 "<%s> %s%s", recipient, host_and_ident(TRUE),
3124 /* Check maximum allowed */
3126 if (rcpt_count > recipients_max && recipients_max > 0)
3128 if (recipients_max_reject)
3131 smtp_printf("552 too many recipients\r\n");
3133 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3134 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3139 smtp_printf("452 too many recipients\r\n");
3141 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3142 "temporarily rejected: sender=<%s> %s", sender_address,
3143 host_and_ident(TRUE));
3150 /* If we have passed the threshold for rate limiting, apply the current
3151 delay, and update it for next time, provided this is a limited host. */
3153 if (rcpt_count > smtp_rlr_threshold &&
3154 verify_check_host(&smtp_ratelimit_hosts) == OK)
3156 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3157 smtp_delay_rcpt/1000.0);
3158 millisleep((int)smtp_delay_rcpt);
3159 smtp_delay_rcpt *= smtp_rlr_factor;
3160 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3161 smtp_delay_rcpt = (double)smtp_rlr_limit;
3164 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3165 for them. Otherwise, check the access control list for this recipient. */
3167 rc = recipients_discarded? DISCARD :
3168 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3170 /* The ACL was happy */
3174 smtp_printf("250 Accepted\r\n");
3175 receive_add_recipient(recipient, -1);
3178 /* The recipient was discarded */
3180 else if (rc == DISCARD)
3182 smtp_printf("250 Accepted\r\n");
3185 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3186 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3187 (sender_address_unrewritten != NULL)?
3188 sender_address_unrewritten : sender_address,
3189 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3190 (log_msg == NULL)? US"" : US": ",
3191 (log_msg == NULL)? US"" : log_msg);
3194 /* Either the ACL failed the address, or it was deferred. */
3198 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3199 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3204 /* The DATA command is legal only if it follows successful MAIL FROM
3205 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3206 not counted as a protocol error if it follows RCPT (which must have been
3207 rejected if there are no recipients.) This function is complete when a
3208 valid DATA command is encountered.
3210 Note concerning the code used: RFC 2821 says this:
3212 - If there was no MAIL, or no RCPT, command, or all such commands
3213 were rejected, the server MAY return a "command out of sequence"
3214 (503) or "no valid recipients" (554) reply in response to the
3217 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3218 because it is the same whether pipelining is in use or not. */
3221 if (!discarded && recipients_count <= 0)
3223 if (pipelining_advertised && last_was_rcpt)
3224 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3226 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3227 US"valid RCPT command must precede DATA");
3231 if (toomany && recipients_max_reject)
3233 sender_address = NULL; /* This will allow a new MAIL without RSET */
3234 sender_address_unrewritten = NULL;
3235 smtp_printf("554 Too many recipients\r\n");
3239 if (acl_smtp_predata == NULL) rc = OK; else
3241 enable_dollar_recipients = TRUE;
3242 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3244 enable_dollar_recipients = FALSE;
3249 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3251 message_ended = END_NOTENDED; /* Indicate in middle of data */
3254 /* Either the ACL failed the address, or it was deferred. */
3257 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3263 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3265 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3271 /* rfc821_domains = TRUE; << no longer needed */
3272 address = parse_extract_address(smtp_cmd_argument, &errmess, &start, &end,
3273 &recipient_domain, FALSE);
3274 /* rfc821_domains = FALSE; << no longer needed */
3276 if (address == NULL)
3277 s = string_sprintf("501 %s", errmess);
3280 address_item *addr = deliver_make_addr(address, FALSE);
3281 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3282 -1, -1, NULL, NULL, NULL))
3285 s = string_sprintf("250 <%s> is deliverable", address);
3289 s = (addr->user_message != NULL)?
3290 string_sprintf("451 <%s> %s", address, addr->user_message) :
3291 string_sprintf("451 Cannot resolve <%s> at this time", address);
3295 s = (addr->user_message != NULL)?
3296 string_sprintf("550 <%s> %s", address, addr->user_message) :
3297 string_sprintf("550 <%s> is not deliverable", address);
3298 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3299 smtp_cmd_argument, host_and_ident(TRUE));
3304 smtp_printf("%s\r\n", s);
3310 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3312 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3315 BOOL save_log_testing_mode = log_testing_mode;
3316 address_test_mode = log_testing_mode = TRUE;
3317 (void) verify_address(deliver_make_addr(smtp_cmd_argument, FALSE),
3318 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3320 address_test_mode = FALSE;
3321 log_testing_mode = save_log_testing_mode; /* true for -bh */
3329 if (!tls_advertised)
3331 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3332 US"STARTTLS command used when not advertised");
3336 /* Apply an ACL check if one is defined */
3338 if (acl_smtp_starttls != NULL)
3340 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3344 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3349 /* RFC 2487 is not clear on when this command may be sent, though it
3350 does state that all information previously obtained from the client
3351 must be discarded if a TLS session is started. It seems reasonble to
3352 do an implied RSET when STARTTLS is received. */
3354 incomplete_transaction_log(US"STARTTLS");
3355 smtp_reset(reset_point);
3357 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3359 /* Attempt to start up a TLS session, and if successful, discard all
3360 knowledge that was obtained previously. At least, that's what the RFC says,
3361 and that's what happens by default. However, in order to work round YAEB,
3362 there is an option to remember the esmtp state. Sigh.
3364 We must allow for an extra EHLO command and an extra AUTH command after
3365 STARTTLS that don't add to the nonmail command count. */
3367 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3369 if (!tls_remember_esmtp)
3370 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3371 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3372 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3373 if (sender_helo_name != NULL)
3375 store_free(sender_helo_name);
3376 sender_helo_name = NULL;
3377 host_build_sender_fullhost(); /* Rebuild */
3378 set_process_info("handling incoming TLS connection from %s",
3379 host_and_ident(FALSE));
3381 received_protocol = (esmtp?
3382 protocols[pextend + pcrpted +
3383 ((sender_host_authenticated != NULL)? pauthed : 0)]
3385 protocols[pnormal + pcrpted])
3387 ((sender_host_address != NULL)? pnlocal : 0);
3389 sender_host_authenticated = NULL;
3390 authenticated_id = NULL;
3391 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3392 DEBUG(D_tls) debug_printf("TLS active\n");
3393 break; /* Successful STARTTLS */
3396 /* Some local configuration problem was discovered before actually trying
3397 to do a TLS handshake; give a temporary error. */
3399 else if (rc == DEFER)
3401 smtp_printf("454 TLS currently unavailable\r\n");
3405 /* Hard failure. Reject everything except QUIT or closed connection. One
3406 cause for failure is a nested STARTTLS, in which case tls_active remains
3407 set, but we must still reject all incoming commands. */
3409 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3412 switch(smtp_read_command(FALSE))
3415 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3416 smtp_get_connection_info());
3421 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3422 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3423 smtp_get_connection_info());
3428 smtp_printf("554 Security failure\r\n");
3437 /* The ACL for QUIT is provided for gathering statistical information or
3438 similar; it does not affect the response code, but it can supply a custom
3442 incomplete_transaction_log(US"QUIT");
3444 if (acl_smtp_quit != NULL)
3446 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit,&user_msg,&log_msg);
3448 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3451 else user_msg = NULL;
3453 if (user_msg == NULL)
3454 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3456 smtp_printf("221 %s\r\n", user_msg);
3463 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3464 smtp_get_connection_info());
3469 incomplete_transaction_log(US"RSET");
3470 smtp_reset(reset_point);
3472 smtp_printf("250 Reset OK\r\n");
3473 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3478 smtp_printf("250 OK\r\n");
3482 /* Show ETRN/EXPN/VRFY if there's
3483 an ACL for checking hosts; if actually used, a check will be done for
3487 smtp_printf("214-Commands supported:\r\n");
3491 Ustrcat(buffer, " AUTH");
3493 Ustrcat(buffer, " STARTTLS");
3495 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3496 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3497 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3498 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3499 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3500 smtp_printf("214%s\r\n", buffer);
3506 incomplete_transaction_log(US"connection lost");
3507 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3509 /* Don't log by default unless in the middle of a message, as some mailers
3510 just drop the call rather than sending QUIT, and it clutters up the logs.
3513 if (sender_address != NULL || recipients_count > 0)
3514 log_write(L_lost_incoming_connection,
3516 "unexpected %s while reading SMTP command from %s%s",
3517 sender_host_unknown? "EOF" : "disconnection",
3518 host_and_ident(FALSE), smtp_read_error);
3520 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3521 smtp_get_connection_info(), smtp_read_error);
3528 if (sender_address != NULL)
3530 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3531 US"ETRN is not permitted inside a transaction");
3535 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
3536 host_and_ident(FALSE));
3538 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
3541 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3545 /* Compute the serialization key for this command. */
3547 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_argument);
3549 /* If a command has been specified for running as a result of ETRN, we
3550 permit any argument to ETRN. If not, only the # standard form is permitted,
3551 since that is strictly the only kind of ETRN that can be implemented
3552 according to the RFC. */
3554 if (smtp_etrn_command != NULL)
3558 etrn_command = smtp_etrn_command;
3559 deliver_domain = smtp_cmd_argument;
3560 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3561 US"ETRN processing", &error);
3562 deliver_domain = NULL;
3565 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3567 smtp_printf("458 Internal failure\r\n");
3572 /* Else set up to call Exim with the -R option. */
3576 if (*smtp_cmd_argument++ != '#')
3578 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3579 US"argument must begin with #");
3582 etrn_command = US"exim -R";
3583 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3587 /* If we are host-testing, don't actually do anything. */
3593 debug_printf("ETRN command is: %s\n", etrn_command);
3594 debug_printf("ETRN command execution skipped\n");
3596 smtp_printf("250 OK\r\n");
3601 /* If ETRN queue runs are to be serialized, check the database to
3602 ensure one isn't already running. */
3604 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3606 smtp_printf("458 Already processing %s\r\n", smtp_cmd_argument);
3610 /* Fork a child process and run the command. We don't want to have to
3611 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3612 forking. It should be set that way anyway for external incoming SMTP,
3613 but we save and restore to be tidy. If serialization is required, we
3614 actually run the command in yet another process, so we can wait for it
3615 to complete and then remove the serialization lock. */
3617 oldsignal = signal(SIGCHLD, SIG_IGN);
3619 if ((pid = fork()) == 0)
3621 smtp_input = FALSE; /* This process is not associated with the */
3622 (void)fclose(smtp_in); /* SMTP call any more. */
3623 (void)fclose(smtp_out);
3625 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3627 /* If not serializing, do the exec right away. Otherwise, fork down
3628 into another process. */
3630 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3632 DEBUG(D_exec) debug_print_argv(argv);
3633 exim_nullstd(); /* Ensure std{in,out,err} exist */
3634 execv(CS argv[0], (char *const *)argv);
3635 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3636 etrn_command, strerror(errno));
3637 _exit(EXIT_FAILURE); /* paranoia */
3640 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3641 is, we are in the first subprocess, after forking again. All we can do
3642 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3643 complete, before removing the serialization. */
3646 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3647 "failed: %s", strerror(errno));
3651 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3653 (void)wait(&status);
3654 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3658 enq_end(etrn_serialize_key);
3659 _exit(EXIT_SUCCESS);
3662 /* Back in the top level SMTP process. Check that we started a subprocess
3663 and restore the signal state. */
3667 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3669 smtp_printf("458 Unable to fork process\r\n");
3670 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3672 else smtp_printf("250 OK\r\n");
3674 signal(SIGCHLD, oldsignal);
3679 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3680 US"unexpected argument data");
3684 /* This currently happens only for NULLs, but could be extended. */
3687 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3688 US"NULL character(s) present (shown as '?')");
3689 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3694 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3695 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3696 c = smtp_inend - smtp_inptr;
3697 if (c > 150) c = 150;
3699 incomplete_transaction_log(US"sync failure");
3700 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
3701 "(next input sent too soon: pipelining was%s advertised): "
3702 "rejected \"%s\" %s next input=\"%s\"",
3703 pipelining_advertised? "" : " not",
3704 smtp_cmd_buffer, host_and_ident(TRUE),
3705 string_printing(smtp_inptr));
3706 smtp_printf("554 SMTP synchronization error\r\n");
3707 done = 1; /* Pretend eof - drops connection */
3711 case TOO_MANY_NONMAIL_CMD:
3712 incomplete_transaction_log(US"too many non-mail commands");
3713 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3714 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
3715 smtp_cmd_argument - smtp_cmd_buffer, smtp_cmd_buffer);
3716 smtp_printf("554 Too many nonmail commands\r\n");
3717 done = 1; /* Pretend eof - drops connection */
3722 if (unknown_command_count++ >= smtp_max_unknown_commands)
3724 log_write(L_smtp_syntax_error, LOG_MAIN,
3725 "SMTP syntax error in \"%s\" %s %s",
3726 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
3727 US"unrecognized command");
3728 incomplete_transaction_log(US"unrecognized command");
3729 smtp_printf("500 Too many unrecognized commands\r\n");
3731 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3732 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3736 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3737 US"unrecognized command");
3741 /* This label is used by goto's inside loops that want to break out to
3742 the end of the command-processing loop. */
3745 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3746 last_was_rcpt = was_rcpt; /* protocol error handling */
3750 return done - 2; /* Convert yield values */
3753 /* End of smtp_in.c */