1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.11 2005/02/17 11:58:26 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2005 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
37 /* Size of buffer for reading SMTP commands */
39 #define cmd_buffer_size 512 /* Ref. RFC 821 */
41 /* Size of buffer for reading SMTP incoming packets */
43 #define in_buffer_size 8192
45 /* Structure for SMTP command list */
52 short int is_mail_cmd;
55 /* Codes for identifying commands. We order them so that those that come first
56 are those for which synchronization is always required. Checking this can help
60 /* These commands are required to be synchronized, i.e. to be the last in a
61 block of commands when pipelining. */
63 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
64 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
65 ETRN_CMD, /* This by analogy with TURN from the RFC */
66 STARTTLS_CMD, /* Required by the STARTTLS RFC */
68 /* This is a dummy to identify the non-sync commands when pipelining */
70 NON_SYNC_CMD_PIPELINING,
72 /* These commands need not be synchronized when pipelining */
74 MAIL_CMD, RCPT_CMD, RSET_CMD,
76 /* This is a dummy to identify the non-sync commands when not pipelining */
78 NON_SYNC_CMD_NON_PIPELINING,
80 /* I have been unable to find a statement about the use of pipelining
81 with AUTH, so to be on the safe side it is here, though I kind of feel
82 it should be up there with the synchronized commands. */
86 /* I'm not sure about these, but I don't think they matter. */
90 /* These are specials that don't correspond to actual commands */
92 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
93 TOO_MANY_NONMAIL_CMD };
97 /*************************************************
98 * Local static variables *
99 *************************************************/
101 static auth_instance *authenticated_by;
102 static BOOL auth_advertised;
104 static BOOL tls_advertised;
107 static BOOL helo_required = FALSE;
108 static BOOL helo_verify = FALSE;
109 static BOOL helo_seen;
110 static BOOL helo_accept_junk;
111 static BOOL count_nonmail;
112 static BOOL pipelining_advertised;
113 static int nonmail_command_count;
114 static int synprot_error_count;
115 static int unknown_command_count;
116 static int sync_cmd_limit;
117 static int smtp_write_error = 0;
119 static uschar *smtp_data;
121 static uschar *cmd_buffer;
123 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
124 final fields of all except AUTH are forced TRUE at the start of a new message
125 setup, to allow one of each between messages that is not counted as a nonmail
126 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
127 allow a new EHLO after starting up TLS.
129 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
130 counted. However, the flag is changed when AUTH is received, so that multiple
131 failing AUTHs will eventually hit the limit. After a successful AUTH, another
132 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
133 forced TRUE, to allow for the re-authentication that can happen at that point.
135 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
136 count of non-mail commands and possibly provoke an error. */
138 static smtp_cmd_list cmd_list[] = {
139 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
140 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
141 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
142 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
144 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
147 /* If you change anything above here, also fix the definitions below. */
149 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
150 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
151 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
152 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
153 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
154 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
155 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
156 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
157 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
160 static smtp_cmd_list *cmd_list_end =
161 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
163 #define CMD_LIST_RSET 0
164 #define CMD_LIST_HELO 1
165 #define CMD_LIST_EHLO 2
166 #define CMD_LIST_AUTH 3
167 #define CMD_LIST_STARTTLS 4
169 static uschar *protocols[] = {
170 US"local-smtp", /* HELO */
171 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
172 US"local-esmtp", /* EHLO */
173 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
174 US"local-esmtpa", /* EHLO->AUTH */
175 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
180 #define pcrpted 1 /* added to pextend or pnormal */
181 #define pauthed 2 /* added to pextend */
182 #define pnlocal 6 /* offset to remove "local" */
184 /* When reading SMTP from a remote host, we have to use our own versions of the
185 C input-reading functions, in order to be able to flush the SMTP output only
186 when about to read more data from the socket. This is the only way to get
187 optimal performance when the client is using pipelining. Flushing for every
188 command causes a separate packet and reply packet each time; saving all the
189 responses up (when pipelining) combines them into one packet and one response.
191 For simplicity, these functions are used for *all* SMTP input, not only when
192 receiving over a socket. However, after setting up a secure socket (SSL), input
193 is read via the OpenSSL library, and another set of functions is used instead
196 These functions are set in the receive_getc etc. variables and called with the
197 same interface as the C functions. However, since there can only ever be
198 one incoming SMTP call, we just use a single buffer and flags. There is no need
199 to implement a complicated private FILE-like structure.*/
201 static uschar *smtp_inbuffer;
202 static uschar *smtp_inptr;
203 static uschar *smtp_inend;
204 static int smtp_had_eof;
205 static int smtp_had_error;
208 /*************************************************
209 * SMTP version of getc() *
210 *************************************************/
212 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
213 it flushes the output, and refills the buffer, with a timeout. The signal
214 handler is set appropriately by the calling function. This function is not used
215 after a connection has negotated itself into an TLS/SSL state.
218 Returns: the next character or EOF
224 if (smtp_inptr >= smtp_inend)
228 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
229 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
234 /* Must put the error text in fixed store, because this might be during
235 header reading, where it releases unused store above the header. */
238 smtp_had_error = save_errno;
239 smtp_read_error = string_copy_malloc(
240 string_sprintf(" (error: %s)", strerror(save_errno)));
242 else smtp_had_eof = 1;
245 smtp_inend = smtp_inbuffer + rc;
246 smtp_inptr = smtp_inbuffer;
248 return *smtp_inptr++;
253 /*************************************************
254 * SMTP version of ungetc() *
255 *************************************************/
257 /* Puts a character back in the input buffer. Only ever
263 Returns: the character
269 *(--smtp_inptr) = ch;
276 /*************************************************
277 * SMTP version of feof() *
278 *************************************************/
280 /* Tests for a previous EOF
283 Returns: non-zero if the eof flag is set
295 /*************************************************
296 * SMTP version of ferror() *
297 *************************************************/
299 /* Tests for a previous read error, and returns with errno
300 restored to what it was when the error was detected.
303 Returns: non-zero if the error flag is set
309 errno = smtp_had_error;
310 return smtp_had_error;
316 /*************************************************
317 * Write formatted string to SMTP channel *
318 *************************************************/
320 /* This is a separate function so that we don't have to repeat everything for
321 TLS support or debugging. It is global so that the daemon and the
322 authentication functions can use it. It does not return any error indication,
323 because major problems such as dropped connections won't show up till an output
324 flush for non-TLS connections. The smtp_fflush() function is available for
325 checking that: for convenience, TLS output errors are remembered here so that
326 they are also picked up later by smtp_fflush().
330 ... optional arguments
336 smtp_printf(char *format, ...)
342 va_start(ap, format);
343 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
344 debug_printf("SMTP>> %s", big_buffer);
347 va_start(ap, format);
349 /* If in a TLS session we have to format the string, and then write it using a
355 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
357 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
358 smtp_closedown(US"Unexpected error");
359 exim_exit(EXIT_FAILURE);
361 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
366 /* Otherwise, just use the standard library function. */
368 if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
374 /*************************************************
375 * Flush SMTP out and check for error *
376 *************************************************/
378 /* This function isn't currently used within Exim (it detects errors when it
379 tries to read the next SMTP input), but is available for use in local_scan().
380 For non-TLS connections, it flushes the output and checks for errors. For
381 TLS-connections, it checks for a previously-detected TLS write error.
384 Returns: 0 for no error; -1 after an error
390 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
391 return smtp_write_error;
396 /*************************************************
397 * SMTP command read timeout *
398 *************************************************/
400 /* Signal handler for timing out incoming SMTP commands. This attempts to
403 Argument: signal number (SIGALRM)
408 command_timeout_handler(int sig)
410 sig = sig; /* Keep picky compilers happy */
411 log_write(L_lost_incoming_connection,
412 LOG_MAIN, "SMTP command timeout on%s connection from %s",
413 (tls_active >= 0)? " TLS" : "",
414 host_and_ident(FALSE));
415 if (smtp_batched_input)
416 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
417 smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
418 smtp_active_hostname);
420 exim_exit(EXIT_FAILURE);
425 /*************************************************
427 *************************************************/
429 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
431 Argument: signal number (SIGTERM)
436 command_sigterm_handler(int sig)
438 sig = sig; /* Keep picky compilers happy */
439 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
440 if (smtp_batched_input)
441 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
442 smtp_printf("421 %s: Service not available - closing connection\r\n",
443 smtp_active_hostname);
444 exim_exit(EXIT_FAILURE);
449 /*************************************************
450 * Read one command line *
451 *************************************************/
453 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
454 There are sites that don't do this, and in any case internal SMTP probably
455 should check only for LF. Consequently, we check here for LF only. The line
456 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
457 an unknown command. The command is read into the static cmd_buffer.
459 The character reading routine sets up a timeout for each block actually read
460 from the input (which may contain more than one command). We set up a special
461 signal handler that closes down the session on a timeout. Control does not
465 check_sync if TRUE, check synchronization rules if global option is TRUE
467 Returns: a code identifying the command (enumerated above)
471 smtp_read_command(BOOL check_sync)
476 BOOL hadnull = FALSE;
478 os_non_restarting_signal(SIGALRM, command_timeout_handler);
480 while ((c = (receive_getc)()) != '\n' && c != EOF)
482 if (ptr >= cmd_buffer_size)
484 os_non_restarting_signal(SIGALRM, sigalrm_handler);
492 cmd_buffer[ptr++] = c;
495 receive_linecount++; /* For BSMTP errors */
496 os_non_restarting_signal(SIGALRM, sigalrm_handler);
498 /* If hit end of file, return pseudo EOF command. Whether we have a
499 part-line already read doesn't matter, since this is an error state. */
501 if (c == EOF) return EOF_CMD;
503 /* Remove any CR and white space at the end of the line, and terminate the
506 while (ptr > 0 && isspace(cmd_buffer[ptr-1])) ptr--;
509 DEBUG(D_receive) debug_printf("SMTP<< %s\n", cmd_buffer);
511 /* NULLs are not allowed in SMTP commands */
513 if (hadnull) return BADCHAR_CMD;
515 /* Scan command list and return identity, having set the data pointer
516 to the start of the actual data characters. Check for SMTP synchronization
519 for (p = cmd_list; p < cmd_list_end; p++)
521 if (strncmpic(cmd_buffer, US p->name, p->len) == 0)
523 if (smtp_inptr < smtp_inend && /* Outstanding input */
524 p->cmd < sync_cmd_limit && /* Command should sync */
525 check_sync && /* Local flag set */
526 smtp_enforce_sync && /* Global flag set */
527 sender_host_address != NULL && /* Not local input */
528 !sender_host_notsocket) /* Really is a socket */
531 /* Point after the command, but don't skip over leading spaces till after
532 the following test, so that if it fails, the command name can easily be
535 smtp_data = cmd_buffer + p->len;
537 /* Count non-mail commands from those hosts that are controlled in this
538 way. The default is all hosts. We don't waste effort checking the list
539 until we get a non-mail command, but then cache the result to save checking
540 again. If there's a DEFER while checking the host, assume it's in the list.
542 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
543 start of each incoming message by fiddling with the value in the table. */
547 if (count_nonmail == TRUE_UNSET) count_nonmail =
548 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
549 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
550 return TOO_MANY_NONMAIL_CMD;
553 /* Get the data pointer over leading spaces and return; if there is no data
554 for a command that expects it, we give the error centrally here. */
556 while (isspace(*smtp_data)) smtp_data++;
557 return (p->has_arg || *smtp_data == 0)? p->cmd : BADARG_CMD;
561 /* Enforce synchronization for unknown commands */
563 if (smtp_inptr < smtp_inend && /* Outstanding input */
564 check_sync && /* Local flag set */
565 smtp_enforce_sync && /* Global flag set */
566 sender_host_address != NULL && /* Not local input */
567 !sender_host_notsocket) /* Really is a socket */
575 /*************************************************
576 * Forced closedown of call *
577 *************************************************/
579 /* This function is called from log.c when Exim is dying because of a serious
580 disaster, and also from some other places. If an incoming non-batched SMTP
581 channel is open, it swallows the rest of the incoming message if in the DATA
582 phase, sends the reply string, and gives an error to all subsequent commands
583 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
586 Argument: SMTP reply string to send, excluding the code
591 smtp_closedown(uschar *message)
593 if (smtp_in == NULL || smtp_batched_input) return;
594 receive_swallow_smtp();
595 smtp_printf("421 %s\r\n", message);
599 switch(smtp_read_command(FALSE))
605 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
610 smtp_printf("250 Reset OK\r\n");
614 smtp_printf("421 %s\r\n", message);
623 /*************************************************
624 * Set up connection info for logging *
625 *************************************************/
627 /* This function is called when logging information about an SMTP connection.
628 It sets up appropriate source information, depending on the type of connection.
631 Returns: a string describing the connection
635 smtp_get_connection_info(void)
638 return string_sprintf("SMTP connection from %s", sender_fullhost);
640 if (sender_host_unknown || sender_host_notsocket)
641 return string_sprintf("SMTP connection from %s", sender_ident);
644 return string_sprintf("SMTP connection from %s (via inetd)", sender_fullhost);
646 if ((log_extra_selector & LX_incoming_interface) != 0 &&
647 interface_address != NULL)
648 return string_sprintf("SMTP connection from %s I=[%s]:%d", sender_fullhost,
649 interface_address, interface_port);
651 return string_sprintf("SMTP connection from %s", sender_fullhost);
656 /*************************************************
657 * Check HELO line and set sender_helo_name *
658 *************************************************/
660 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
661 the domain name of the sending host, or an ip literal in square brackets. The
662 arrgument is placed in sender_helo_name, which is in malloc store, because it
663 must persist over multiple incoming messages. If helo_accept_junk is set, this
664 host is permitted to send any old junk (needed for some broken hosts).
665 Otherwise, helo_allow_chars can be used for rogue characters in general
666 (typically people want to let in underscores).
669 s the data portion of the line (already past any white space)
671 Returns: TRUE or FALSE
675 check_helo(uschar *s)
678 uschar *end = s + Ustrlen(s);
679 BOOL yield = helo_accept_junk;
681 /* Discard any previous helo name */
683 if (sender_helo_name != NULL)
685 store_free(sender_helo_name);
686 sender_helo_name = NULL;
689 /* Skip tests if junk is permitted. */
693 /* Allow the new standard form for IPv6 address literals, namely,
694 [IPv6:....], and because someone is bound to use it, allow an equivalent
695 IPv4 form. Allow plain addresses as well. */
702 if (strncmpic(s, US"[IPv6:", 6) == 0)
703 yield = (string_is_ip_address(s+6, NULL) == 6);
704 else if (strncmpic(s, US"[IPv4:", 6) == 0)
705 yield = (string_is_ip_address(s+6, NULL) == 4);
707 yield = (string_is_ip_address(s+1, NULL) != 0);
712 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
713 that have been configured (usually underscore - sigh). */
720 if (!isalnum(*s) && *s != '.' && *s != '-' &&
721 Ustrchr(helo_allow_chars, *s) == NULL)
731 /* Save argument if OK */
733 if (yield) sender_helo_name = string_copy_malloc(start);
741 /*************************************************
742 * Extract SMTP command option *
743 *************************************************/
745 /* This function picks the next option setting off the end of smtp_data. It
746 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
747 things that can appear there.
750 name point this at the name
751 value point this at the data string
753 Returns: TRUE if found an option
757 extract_option(uschar **name, uschar **value)
760 uschar *v = smtp_data + Ustrlen(smtp_data) -1;
761 while (isspace(*v)) v--;
764 while (v > smtp_data && *v != '=' && !isspace(*v)) v--;
765 if (*v != '=') return FALSE;
768 while(isalpha(n[-1])) n--;
770 if (n[-1] != ' ') return FALSE;
785 /*************************************************
786 * Reset for new message *
787 *************************************************/
789 /* This function is called whenever the SMTP session is reset from
790 within either of the setup functions.
792 Argument: the stacking pool storage reset point
797 smtp_reset(void *reset_point)
800 store_reset(reset_point);
801 recipients_list = NULL;
802 rcpt_count = rcpt_defer_count = rcpt_fail_count =
803 raw_recipients_count = recipients_count = recipients_list_max = 0;
805 acl_warn_headers = NULL;
806 queue_only_policy = FALSE;
807 deliver_freeze = FALSE; /* Can be set by ACL */
808 fake_reject = FALSE; /* Can be set by ACL */
809 #ifdef WITH_CONTENT_SCAN
810 no_mbox_unspool = FALSE; /* Can be set by ACL */
812 submission_mode = FALSE; /* Can be set by ACL */
813 active_local_from_check = local_from_check; /* Can be set by ACL */
814 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
815 sender_address = NULL;
816 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
817 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
818 sender_verified_list = NULL; /* No senders verified */
819 memset(sender_address_cache, 0, sizeof(sender_address_cache));
820 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
821 authenticated_sender = NULL;
822 #ifdef EXPERIMENTAL_BRIGHTMAIL
826 #ifdef EXPERIMENTAL_SPF
827 spf_header_comment = NULL;
830 spf_smtp_comment = NULL;
832 body_linecount = body_zerocount = 0;
834 for (i = 0; i < ACL_M_MAX; i++) acl_var[ACL_C_MAX + i] = NULL;
836 /* The message body variables use malloc store. They may be set if this is
837 not the first message in an SMTP session and the previous message caused them
838 to be referenced in an ACL. */
840 if (message_body != NULL)
842 store_free(message_body);
846 if (message_body_end != NULL)
848 store_free(message_body_end);
849 message_body_end = NULL;
852 /* Warning log messages are also saved in malloc store. They are saved to avoid
853 repetition in the same message, but it seems right to repeat them for different
856 while (acl_warn_logged != NULL)
858 string_item *this = acl_warn_logged;
859 acl_warn_logged = acl_warn_logged->next;
868 /*************************************************
869 * Initialize for incoming batched SMTP message *
870 *************************************************/
872 /* This function is called from smtp_setup_msg() in the case when
873 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
874 of messages in one file with SMTP commands between them. All errors must be
875 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
876 relevant. After an error on a sender, or an invalid recipient, the remainder
877 of the message is skipped. The value of received_protocol is already set.
880 Returns: > 0 message successfully started (reached DATA)
881 = 0 QUIT read or end of file reached
886 smtp_setup_batch_msg(void)
889 void *reset_point = store_get(0);
891 /* Save the line count at the start of each transaction - single commands
892 like HELO and RSET count as whole transactions. */
894 bsmtp_transaction_linecount = receive_linecount;
896 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
898 smtp_reset(reset_point); /* Reset for start of message */
900 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
901 value. The values are 2 larger than the required yield of the function. */
906 uschar *recipient = NULL;
907 int start, end, sender_domain, recipient_domain;
909 switch(smtp_read_command(FALSE))
911 /* The HELO/EHLO commands set sender_address_helo if they have
912 valid data; otherwise they are ignored, except that they do
913 a reset of the state. */
918 check_helo(smtp_data);
922 smtp_reset(reset_point);
923 bsmtp_transaction_linecount = receive_linecount;
927 /* The MAIL FROM command requires an address as an operand. All we
928 do here is to parse it for syntactic correctness. The form "<>" is
929 a special case which converts into an empty string. The start/end
930 pointers in the original are not used further for this address, as
931 it is the canonical extracted address which is all that is kept. */
934 if (sender_address != NULL)
935 /* The function moan_smtp_batch() does not return. */
936 moan_smtp_batch(cmd_buffer, "503 Sender already given");
938 if (smtp_data[0] == 0)
939 /* The function moan_smtp_batch() does not return. */
940 moan_smtp_batch(cmd_buffer, "501 MAIL FROM must have an address operand");
942 /* Reset to start of message */
944 smtp_reset(reset_point);
946 /* Apply SMTP rewrite */
948 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
949 rewrite_one(smtp_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
950 US"", global_rewrite_rules) : smtp_data;
952 /* Extract the address; the TRUE flag allows <> as valid */
955 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
958 if (raw_sender == NULL)
959 /* The function moan_smtp_batch() does not return. */
960 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
962 sender_address = string_copy(raw_sender);
964 /* Qualify unqualified sender addresses if permitted to do so. */
966 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
968 if (allow_unqualified_sender)
970 sender_address = rewrite_address_qualify(sender_address, FALSE);
971 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
972 "and rewritten\n", raw_sender);
974 /* The function moan_smtp_batch() does not return. */
975 else moan_smtp_batch(cmd_buffer, "501 sender address must contain "
981 /* The RCPT TO command requires an address as an operand. All we do
982 here is to parse it for syntactic correctness. There may be any number
983 of RCPT TO commands, specifying multiple senders. We build them all into
984 a data structure that is in argc/argv format. The start/end values
985 given by parse_extract_address are not used, as we keep only the
986 extracted address. */
989 if (sender_address == NULL)
990 /* The function moan_smtp_batch() does not return. */
991 moan_smtp_batch(cmd_buffer, "503 No sender yet given");
993 if (smtp_data[0] == 0)
994 /* The function moan_smtp_batch() does not return. */
995 moan_smtp_batch(cmd_buffer, "501 RCPT TO must have an address operand");
997 /* Check maximum number allowed */
999 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1000 /* The function moan_smtp_batch() does not return. */
1001 moan_smtp_batch(cmd_buffer, "%s too many recipients",
1002 recipients_max_reject? "552": "452");
1004 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1005 recipient address */
1007 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1008 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
1009 global_rewrite_rules) : smtp_data;
1011 /* rfc821_domains = TRUE; << no longer needed */
1012 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1013 &recipient_domain, FALSE);
1014 /* rfc821_domains = FALSE; << no longer needed */
1016 if (recipient == NULL)
1017 /* The function moan_smtp_batch() does not return. */
1018 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
1020 /* If the recipient address is unqualified, qualify it if permitted. Then
1021 add it to the list of recipients. */
1023 if (recipient_domain == 0)
1025 if (allow_unqualified_recipient)
1027 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1029 recipient = rewrite_address_qualify(recipient, TRUE);
1031 /* The function moan_smtp_batch() does not return. */
1032 else moan_smtp_batch(cmd_buffer, "501 recipient address must contain "
1035 receive_add_recipient(recipient, -1);
1039 /* The DATA command is legal only if it follows successful MAIL FROM
1040 and RCPT TO commands. This function is complete when a valid DATA
1041 command is encountered. */
1044 if (sender_address == NULL || recipients_count <= 0)
1046 /* The function moan_smtp_batch() does not return. */
1047 if (sender_address == NULL)
1048 moan_smtp_batch(cmd_buffer,
1049 "503 MAIL FROM:<sender> command must precede DATA");
1051 moan_smtp_batch(cmd_buffer,
1052 "503 RCPT TO:<recipient> must precede DATA");
1056 done = 3; /* DATA successfully achieved */
1057 message_ended = END_NOTENDED; /* Indicate in middle of message */
1062 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1069 bsmtp_transaction_linecount = receive_linecount;
1080 /* The function moan_smtp_batch() does not return. */
1081 moan_smtp_batch(cmd_buffer, "501 Unexpected argument data");
1086 /* The function moan_smtp_batch() does not return. */
1087 moan_smtp_batch(cmd_buffer, "501 Unexpected NULL in SMTP command");
1092 /* The function moan_smtp_batch() does not return. */
1093 moan_smtp_batch(cmd_buffer, "500 Command unrecognized");
1098 return done - 2; /* Convert yield values */
1104 /*************************************************
1105 * Start an SMTP session *
1106 *************************************************/
1108 /* This function is called at the start of an SMTP session. Thereafter,
1109 smtp_setup_msg() is called to initiate each separate message. This
1110 function does host-specific testing, and outputs the banner line.
1113 Returns: FALSE if the session can not continue; something has
1114 gone wrong, or the connection to the host is blocked
1118 smtp_start_session(void)
1124 /* If we are running in the test harness, and the incoming call is from
1125 127.0.0.2 (sic), have a short delay. This makes it possible to test handling of
1126 input sent too soon (before the banner is output). */
1128 if (running_in_test_harness &&
1129 sender_host_address != NULL &&
1130 Ustrcmp(sender_host_address, "127.0.0.2") == 0)
1133 /* Default values for certain variables */
1135 helo_seen = esmtp = helo_accept_junk = FALSE;
1136 count_nonmail = TRUE_UNSET;
1137 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1138 smtp_delay_mail = smtp_rlm_base;
1139 auth_advertised = FALSE;
1140 pipelining_advertised = FALSE;
1141 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1143 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1145 sender_host_authenticated = NULL;
1146 authenticated_by = NULL;
1149 tls_cipher = tls_peerdn = NULL;
1150 tls_advertised = FALSE;
1153 /* Reset ACL connection variables */
1155 for (i = 0; i < ACL_C_MAX; i++) acl_var[i] = NULL;
1157 cmd_buffer = (uschar *)malloc(cmd_buffer_size + 1); /* allow for trailing 0 */
1158 if (cmd_buffer == NULL)
1159 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1160 "malloc() failed for SMTP command buffer");
1162 /* For batched input, the protocol setting can be overridden from the
1163 command line by a trusted caller. */
1165 if (smtp_batched_input)
1167 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1170 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1171 reset later if any of EHLO/AUTH/STARTTLS are received. */
1175 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1177 /* Set up the buffer for inputting using direct read() calls, and arrange to
1178 call the local functions instead of the standard C ones. */
1180 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1181 if (smtp_inbuffer == NULL)
1182 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1183 receive_getc = smtp_getc;
1184 receive_ungetc = smtp_ungetc;
1185 receive_feof = smtp_feof;
1186 receive_ferror = smtp_ferror;
1187 smtp_inptr = smtp_inend = smtp_inbuffer;
1188 smtp_had_eof = smtp_had_error = 0;
1190 /* Set up the message size limit; this may be host-specific */
1192 thismessage_size_limit = expand_string_integer(message_size_limit);
1193 if (thismessage_size_limit < 0)
1195 if (thismessage_size_limit == -1)
1196 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1197 "%s", expand_string_message);
1199 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1200 "%s", expand_string_message);
1201 smtp_closedown(US"Temporary local problem - please try later");
1205 /* When a message is input locally via the -bs or -bS options, sender_host_
1206 unknown is set unless -oMa was used to force an IP address, in which case it
1207 is checked like a real remote connection. When -bs is used from inetd, this
1208 flag is not set, causing the sending host to be checked. The code that deals
1209 with IP source routing (if configured) is never required for -bs or -bS and
1210 the flag sender_host_notsocket is used to suppress it.
1212 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1213 reserve for certain hosts and/or networks. */
1215 if (!sender_host_unknown)
1218 BOOL reserved_host = FALSE;
1220 /* Look up IP options (source routing info) on the socket if this is not an
1221 -oMa "host", and if any are found, log them and drop the connection.
1223 Linux (and others now, see below) is different to everyone else, so there
1224 has to be some conditional compilation here. Versions of Linux before 2.1.15
1225 used a structure whose name was "options". Somebody finally realized that
1226 this name was silly, and it got changed to "ip_options". I use the
1227 newer name here, but there is a fudge in the script that sets up os.h
1228 to define a macro in older Linux systems.
1230 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1231 glibc 2, which has chosen ip_opts for the structure name. This is now
1232 really a glibc thing rather than a Linux thing, so the condition name
1233 has been changed to reflect this. It is relevant also to GNU/Hurd.
1235 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1236 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1237 a special macro defined in the os.h file.
1239 Some DGUX versions on older hardware appear not to support IP options at
1240 all, so there is now a general macro which can be set to cut out this
1243 How to do this properly in IPv6 is not yet known. */
1245 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1247 #ifdef GLIBC_IP_OPTIONS
1248 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1253 #elif defined DARWIN_IP_OPTIONS
1259 if (!host_checking && !sender_host_notsocket)
1262 SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1263 struct ip_options *ipopt = store_get(optlen);
1265 struct ip_opts ipoptblock;
1266 struct ip_opts *ipopt = &ipoptblock;
1267 SOCKLEN_T optlen = sizeof(ipoptblock);
1269 struct ipoption ipoptblock;
1270 struct ipoption *ipopt = &ipoptblock;
1271 SOCKLEN_T optlen = sizeof(ipoptblock);
1274 /* Occasional genuine failures of getsockopt() have been seen - for
1275 example, "reset by peer". Therefore, just log and give up on this
1276 call, unless the error is ENOPROTOOPT. This error is given by systems
1277 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1278 of writing. So for that error, carry on - we just can't do an IP options
1281 DEBUG(D_receive) debug_printf("checking for IP options\n");
1283 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1286 if (errno != ENOPROTOOPT)
1288 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1289 host_and_ident(FALSE), strerror(errno));
1290 smtp_printf("451 SMTP service not available\r\n");
1295 /* Deal with any IP options that are set. On the systems I have looked at,
1296 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1297 more logging data than will fit in big_buffer. Nevertheless, after somebody
1298 questioned this code, I've added in some paranoid checking. */
1300 else if (optlen > 0)
1302 uschar *p = big_buffer;
1303 uschar *pend = big_buffer + big_buffer_size;
1304 uschar *opt, *adptr;
1306 struct in_addr addr;
1309 uschar *optstart = (uschar *)(ipopt->__data);
1311 uschar *optstart = (uschar *)(ipopt->ip_opts);
1313 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1316 DEBUG(D_receive) debug_printf("IP options exist\n");
1318 Ustrcpy(p, "IP options on incoming call:");
1321 for (opt = optstart; opt != NULL &&
1322 opt < (uschar *)(ipopt) + optlen;)
1336 if (!string_format(p, pend-p, " %s [@%s",
1337 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1339 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1341 inet_ntoa(ipopt->ip_dst)))
1343 inet_ntoa(ipopt->ipopt_dst)))
1351 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1353 while (optcount-- > 0)
1355 memcpy(&addr, adptr, sizeof(addr));
1356 if (!string_format(p, pend - p - 1, "%s%s",
1357 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1363 adptr += sizeof(struct in_addr);
1372 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1375 for (i = 0; i < opt[1]; i++)
1377 sprintf(CS p, "%2.2x ", opt[i]);
1388 log_write(0, LOG_MAIN, "%s", big_buffer);
1390 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1392 log_write(0, LOG_MAIN|LOG_REJECT,
1393 "connection from %s refused (IP options)", host_and_ident(FALSE));
1395 smtp_printf("554 SMTP service not available\r\n");
1399 /* Length of options = 0 => there are no options */
1401 else DEBUG(D_receive) debug_printf("no IP options found\n");
1403 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1405 /* Set keep-alive in socket options. The option is on by default. This
1406 setting is an attempt to get rid of some hanging connections that stick in
1407 read() when the remote end (usually a dialup) goes away. */
1409 if (smtp_accept_keepalive && !sender_host_notsocket)
1410 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1412 /* If the current host matches host_lookup, set the name by doing a
1413 reverse lookup. On failure, sender_host_name will be NULL and
1414 host_lookup_failed will be TRUE. This may or may not be serious - optional
1417 if (verify_check_host(&host_lookup) == OK)
1419 (void)host_name_lookup();
1420 host_build_sender_fullhost();
1423 /* Delay this until we have the full name, if it is looked up. */
1425 set_process_info("handling incoming connection from %s",
1426 host_and_ident(FALSE));
1428 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1429 smtps port for use with older style SSL MTAs. */
1432 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1436 /* Test for explicit connection rejection */
1438 if (verify_check_host(&host_reject_connection) == OK)
1440 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1441 "from %s (host_reject_connection)", host_and_ident(FALSE));
1442 smtp_printf("554 SMTP service not available\r\n");
1446 /* Test with TCP Wrappers if so configured */
1448 #ifdef USE_TCP_WRAPPERS
1449 if (!hosts_ctl("exim",
1450 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1451 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1452 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1454 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1455 log_write(L_connection_reject,
1456 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1457 "(tcp wrappers)", host_and_ident(FALSE));
1458 smtp_printf("554 SMTP service not available\r\n");
1463 /* Check for reserved slots. Note that the count value doesn't include
1464 this process, as it gets upped in the parent process. */
1466 if (smtp_accept_max > 0 &&
1467 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1469 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1471 log_write(L_connection_reject,
1472 LOG_MAIN, "temporarily refused connection from %s: not in "
1473 "reserve list: connected=%d max=%d reserve=%d%s",
1474 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1475 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1476 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1477 "please try again later\r\n", smtp_active_hostname);
1480 reserved_host = TRUE;
1483 /* If a load level above which only messages from reserved hosts are
1484 accepted is set, check the load. For incoming calls via the daemon, the
1485 check is done in the superior process if there are no reserved hosts, to
1486 save a fork. In all cases, the load average will already be available
1487 in a global variable at this point. */
1489 if (smtp_load_reserve >= 0 &&
1490 load_average > smtp_load_reserve &&
1492 verify_check_host(&smtp_reserve_hosts) != OK)
1494 log_write(L_connection_reject,
1495 LOG_MAIN, "temporarily refused connection from %s: not in "
1496 "reserve list and load average = %.2f", host_and_ident(FALSE),
1497 (double)load_average/1000.0);
1498 smtp_printf("421 %s: Too much load; please try again later\r\n",
1499 smtp_active_hostname);
1503 /* Determine whether unqualified senders or recipients are permitted
1504 for this host. Unfortunately, we have to do this every time, in order to
1505 set the flags so that they can be inspected when considering qualifying
1506 addresses in the headers. For a site that permits no qualification, this
1507 won't take long, however. */
1509 allow_unqualified_sender =
1510 verify_check_host(&sender_unqualified_hosts) == OK;
1512 allow_unqualified_recipient =
1513 verify_check_host(&recipient_unqualified_hosts) == OK;
1515 /* Determine whether HELO/EHLO is required for this host. The requirement
1516 can be hard or soft. */
1518 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1520 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1522 /* Determine whether this hosts is permitted to send syntactic junk
1523 after a HELO or EHLO command. */
1525 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1528 /* For batch SMTP input we are now done. */
1530 if (smtp_batched_input) return TRUE;
1532 /* Run the ACL if it exists */
1534 if (acl_smtp_connect != NULL)
1537 uschar *user_msg, *log_msg;
1538 smtp_data = US"in \"connect\" ACL"; /* For logged failure message */
1539 rc = acl_check(ACL_WHERE_CONNECT, US"", acl_smtp_connect, &user_msg,
1543 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1548 /* Output the initial message for a two-way SMTP connection. It may contain
1549 newlines, which then cause a multi-line response to be given. */
1551 s = expand_string(smtp_banner);
1553 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1554 "failed: %s", smtp_banner, expand_string_message);
1556 /* Remove any terminating newlines; might as well remove trailing space too */
1559 while (p > s && isspace(p[-1])) p--;
1562 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1563 is all contained in a single IP packet. The original code wrote out the
1564 greeting using several calls to fprint/fputc, and on busy servers this could
1565 cause it to be split over more than one packet - which caused CC:Mail to fall
1566 over when it got the second part of the greeting after sending its first
1567 command. Sigh. To try to avoid this, build the complete greeting message
1568 first, and output it in one fell swoop. This gives a better chance of it
1569 ending up as a single packet. */
1571 ss = store_get(size);
1575 do /* At least once, in case we have an empty string */
1578 uschar *linebreak = Ustrchr(p, '\n');
1579 if (linebreak == NULL)
1582 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1586 len = linebreak - p;
1587 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1589 ss = string_cat(ss, &size, &ptr, p, len);
1590 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1592 if (linebreak != NULL) p++;
1596 ss[ptr] = 0; /* string_cat leaves room for this */
1598 /* Before we write the banner, check that there is no input pending, unless
1599 this synchronisation check is disabled. */
1601 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1604 struct timeval tzero;
1608 FD_SET(fileno(smtp_in), &fds);
1609 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1612 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1613 if (rc > 150) rc = 150;
1614 smtp_inbuffer[rc] = 0;
1615 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: "
1616 "synchronization error (input sent without waiting for greeting): "
1617 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1618 string_printing(smtp_inbuffer));
1619 smtp_printf("554 SMTP synchronization error\r\n");
1624 /* Now output the banner */
1626 smtp_printf("%s", ss);
1634 /*************************************************
1635 * Handle SMTP syntax and protocol errors *
1636 *************************************************/
1638 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1639 to do so. Then transmit the error response. The return value depends on the
1640 number of syntax and protocol errors in this SMTP session.
1643 type error type, given as a log flag bit
1644 code response code; <= 0 means don't send a response
1645 data data to reflect in the response (can be NULL)
1646 errmess the error message
1648 Returns: -1 limit of syntax/protocol errors NOT exceeded
1649 +1 limit of syntax/protocol errors IS exceeded
1651 These values fit in with the values of the "done" variable in the main
1652 processing loop in smtp_setup_msg(). */
1655 synprot_error(int type, int code, uschar *data, uschar *errmess)
1659 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1660 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1661 string_printing(cmd_buffer), host_and_ident(TRUE), errmess);
1663 if (++synprot_error_count > smtp_max_synprot_errors)
1666 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1667 "syntax or protocol errors (last command was \"%s\")",
1668 host_and_ident(FALSE), cmd_buffer);
1673 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1674 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1676 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1685 /*************************************************
1686 * Log incomplete transactions *
1687 *************************************************/
1689 /* This function is called after a transaction has been aborted by RSET, QUIT,
1690 connection drops or other errors. It logs the envelope information received
1691 so far in order to preserve address verification attempts.
1693 Argument: string to indicate what aborted the transaction
1698 incomplete_transaction_log(uschar *what)
1700 if (sender_address == NULL || /* No transaction in progress */
1701 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1704 /* Build list of recipients for logging */
1706 if (recipients_count > 0)
1709 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1710 for (i = 0; i < recipients_count; i++)
1711 raw_recipients[i] = recipients_list[i].address;
1712 raw_recipients_count = recipients_count;
1715 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1716 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1722 /*************************************************
1723 * Send SMTP response, possibly multiline *
1724 *************************************************/
1726 /* There are, it seems, broken clients out there that cannot handle multiline
1727 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1728 output nothing for non-final calls, and only the first line for anything else.
1732 final FALSE if the last line isn't the final line
1733 msg message text, possibly containing newlines
1739 smtp_respond(int code, BOOL final, uschar *msg)
1741 if (!final && no_multiline_responses) return;
1745 uschar *nl = Ustrchr(msg, '\n');
1748 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1751 else if (nl[1] == 0 || no_multiline_responses)
1753 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1758 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1760 while (isspace(*msg)) msg++;
1768 /*************************************************
1769 * Handle an ACL failure *
1770 *************************************************/
1772 /* This function is called when acl_check() fails. As well as calls from within
1773 this module, it is called from receive.c for an ACL after DATA. It sorts out
1774 logging the incident, and sets up the error response. A message containing
1775 newlines is turned into a multiline SMTP response, but for logging, only the
1778 There's a table of the response codes to use in globals.c, along with the table
1779 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1780 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1781 that the response should be 252 in the disabled state, because there are broken
1782 clients that try VRFY before RCPT. A 5xx response should be given only when the
1783 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1784 given on refusal, and for AUTH, 503.
1787 where where the ACL was called from
1789 user_msg a message that can be included in an SMTP response
1790 log_msg a message for logging
1792 Returns: 0 in most cases
1793 2 if the failure code was FAIL_DROP, in which case the
1794 SMTP connection should be dropped (this value fits with the
1795 "done" variable in smtp_setup_msg() below)
1799 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1801 int code = acl_wherecodes[where];
1802 BOOL drop = rc == FAIL_DROP;
1804 uschar *sender_info = US"";
1805 uschar *what = (where == ACL_WHERE_PREDATA)? US"DATA" :
1806 #ifdef WITH_CONTENT_SCAN
1807 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1809 (where == ACL_WHERE_DATA)? US"after DATA" :
1810 string_sprintf("%s %s", acl_wherenames[where], smtp_data);
1812 if (drop) rc = FAIL;
1814 /* We used to have sender_address here; however, there was a bug that was not
1815 updating sender_address after a rewrite during a verify. When this bug was
1816 fixed, sender_address at this point became the rewritten address. I'm not sure
1817 this is what should be logged, so I've changed to logging the unrewritten
1818 address to retain backward compatibility. */
1820 #ifndef WITH_CONTENT_SCAN
1821 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1823 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1826 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1827 sender_address_unrewritten : sender_address);
1830 /* If there's been a sender verification failure with a specific message, and
1831 we have not sent a response about it yet, do so now, as a preliminary line for
1832 failures, but not defers. However, log it in both cases. */
1834 if (sender_verified_failed != NULL &&
1835 !testflag(sender_verified_failed, af_sverify_told))
1837 setflag(sender_verified_failed, af_sverify_told);
1839 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1840 host_and_ident(TRUE),
1841 ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail",
1842 sender_verified_failed->address,
1843 (sender_verified_failed->message == NULL)? US"" :
1844 string_sprintf(": %s", sender_verified_failed->message));
1846 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1847 smtp_respond(code, FALSE, string_sprintf(
1848 testflag(sender_verified_failed, af_verify_pmfail)?
1849 "Postmaster verification failed while checking <%s>\n%s\n"
1850 "Several RFCs state that you are required to have a postmaster\n"
1851 "mailbox for each mail domain. This host does not accept mail\n"
1852 "from domains whose servers reject the postmaster address."
1854 testflag(sender_verified_failed, af_verify_nsfail)?
1855 "Callback setup failed while verifying <%s>\n%s\n"
1856 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1857 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1858 "RFC requirements, and stops you from receiving standard bounce\n"
1859 "messages. This host does not accept mail from domains whose servers\n"
1862 "Verification failed for <%s>\n%s",
1863 sender_verified_failed->address,
1864 sender_verified_failed->user_message));
1867 /* Sort out text for logging */
1869 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1870 lognl = Ustrchr(log_msg, '\n');
1871 if (lognl != NULL) *lognl = 0;
1873 /* Send permanent failure response to the command, but the code used isn't
1874 always a 5xx one - see comments at the start of this function. If the original
1875 rc was FAIL_DROP we drop the connection and yield 2. */
1877 if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1878 US"Administrative prohibition" : user_msg);
1880 /* Send temporary failure response to the command. Don't give any details,
1881 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1882 verb, and for a header verify when smtp_return_error_details is set.
1884 This conditional logic is all somewhat of a mess because of the odd
1885 interactions between temp_details and return_error_details. One day it should
1886 be re-implemented in a tidier fashion. */
1890 if (acl_temp_details && user_msg != NULL)
1892 if (smtp_return_error_details &&
1893 sender_verified_failed != NULL &&
1894 sender_verified_failed->message != NULL)
1896 smtp_respond(451, FALSE, sender_verified_failed->message);
1898 smtp_respond(451, TRUE, user_msg);
1901 smtp_printf("451 Temporary local problem - please try later\r\n");
1904 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
1905 Otherwise, log why it is closing if required and return 2. */
1907 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1908 host_and_ident(TRUE),
1909 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1911 if (!drop) return 0;
1913 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1914 smtp_get_connection_info());
1921 /*************************************************
1922 * Initialize for SMTP incoming message *
1923 *************************************************/
1925 /* This function conducts the initial dialogue at the start of an incoming SMTP
1926 message, and builds a list of recipients. However, if the incoming message
1927 is part of a batch (-bS option) a separate function is called since it would
1928 be messy having tests splattered about all over this function. This function
1929 therefore handles the case where interaction is occurring. The input and output
1930 files are set up in smtp_in and smtp_out.
1932 The global recipients_list is set to point to a vector of recipient_item
1933 blocks, whose number is given by recipients_count. This is extended by the
1934 receive_add_recipient() function. The global variable sender_address is set to
1935 the sender's address. The yield is +1 if a message has been successfully
1936 started, 0 if a QUIT command was encountered or the connection was refused from
1937 the particular host, or -1 if the connection was lost.
1941 Returns: > 0 message successfully started (reached DATA)
1942 = 0 QUIT read or end of file reached or call refused
1947 smtp_setup_msg(void)
1950 BOOL toomany = FALSE;
1951 BOOL discarded = FALSE;
1952 BOOL last_was_rej_mail = FALSE;
1953 BOOL last_was_rcpt = FALSE;
1954 void *reset_point = store_get(0);
1956 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
1958 /* Reset for start of new message. We allow one RSET not to be counted as a
1959 nonmail command, for those MTAs that insist on sending it between every
1960 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
1961 TLS between messages (an Exim client may do this if it has messages queued up
1962 for the host). Note: we do NOT reset AUTH at this point. */
1964 smtp_reset(reset_point);
1965 message_ended = END_NOTSTARTED;
1967 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
1968 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
1969 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
1971 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
1974 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
1976 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
1978 /* Batched SMTP is handled in a different function. */
1980 if (smtp_batched_input) return smtp_setup_batch_msg();
1982 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1983 value. The values are 2 larger than the required yield of the function. */
1988 uschar *etrn_command;
1989 uschar *etrn_serialize_key;
1991 uschar *user_msg, *log_msg;
1992 uschar *recipient = NULL;
1993 uschar *hello = NULL;
1994 uschar *set_id = NULL;
1996 BOOL was_rej_mail = FALSE;
1997 BOOL was_rcpt = FALSE;
1998 void (*oldsignal)(int);
2000 int start, end, sender_domain, recipient_domain;
2005 switch(smtp_read_command(TRUE))
2007 /* The AUTH command is not permitted to occur inside a transaction, and may
2008 occur successfully only once per connection, and then only when we've
2009 advertised it. Actually, that isn't quite true. When TLS is started, all
2010 previous information about a connection must be discarded, so a new AUTH is
2011 permitted at that time.
2013 AUTH is initially labelled as a "nonmail command" so that one occurrence
2014 doesn't get counted. We change the label here so that multiple failing
2015 AUTHS will eventually hit the nonmail threshold. */
2018 authentication_failed = TRUE;
2019 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2021 if (!auth_advertised)
2023 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2024 US"AUTH command used when not advertised");
2027 if (sender_host_authenticated != NULL)
2029 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2030 US"already authenticated");
2033 if (sender_address != NULL)
2035 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2036 US"not permitted in mail transaction");
2042 if (acl_smtp_auth != NULL)
2044 rc = acl_check(ACL_WHERE_AUTH, smtp_data, acl_smtp_auth, &user_msg,
2048 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2053 /* Find the name of the requested authentication mechanism. */
2056 while ((c = *smtp_data) != 0 && !isspace(c))
2058 if (!isalnum(c) && c != '-' && c != '_')
2060 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2061 US"invalid character in authentication mechanism name");
2067 /* If not at the end of the line, we must be at white space. Terminate the
2068 name and move the pointer on to any data that may be present. */
2070 if (*smtp_data != 0)
2073 while (isspace(*smtp_data)) smtp_data++;
2076 /* Search for an authentication mechanism which is configured for use
2077 as a server and which has been advertised. */
2079 for (au = auths; au != NULL; au = au->next)
2081 if (strcmpic(s, au->public_name) == 0 && au->server &&
2082 au->advertised) break;
2087 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2088 string_sprintf("%s authentication mechanism not supported", s));
2092 /* Run the checking code, passing the remainder of the command
2093 line as data. Initialize $0 empty. The authenticator may set up
2094 other numeric variables. Afterwards, have a go at expanding the set_id
2095 string, even if authentication failed - for bad passwords it can be useful
2096 to log the userid. On success, require set_id to expand and exist, and
2097 put it in authenticated_id. Save this in permanent store, as the working
2098 store gets reset at HELO, RSET, etc. */
2101 expand_nlength[0] = 0; /* $0 contains nothing */
2103 c = (au->info->servercode)(au, smtp_data);
2104 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2105 expand_nmax = -1; /* Reset numeric variables */
2107 /* For the non-OK cases, set up additional logging data if set_id
2112 if (set_id != NULL && *set_id != 0)
2113 set_id = string_sprintf(" (set_id=%s)", set_id);
2117 /* Switch on the result */
2122 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2124 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2125 sender_host_authenticated = au->name;
2126 authentication_failed = FALSE;
2128 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2129 ((sender_host_address != NULL)? pnlocal : 0);
2130 s = ss = US"235 Authentication succeeded";
2131 authenticated_by = au;
2135 /* Authentication succeeded, but we failed to expand the set_id string.
2136 Treat this as a temporary error. */
2138 auth_defer_msg = expand_string_message;
2142 s = string_sprintf("435 Unable to authenticate at present%s",
2143 auth_defer_user_msg);
2144 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2145 set_id, auth_defer_msg);
2149 s = ss = US"501 Invalid base64 data";
2153 s = ss = US"501 Authentication cancelled";
2157 s = ss = US"553 Initial data not expected";
2161 s = US"535 Incorrect authentication data";
2162 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2166 s = US"435 Internal error";
2167 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2168 "check", set_id, c);
2172 smtp_printf("%s\r\n", s);
2174 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2175 au->name, host_and_ident(FALSE), ss);
2177 break; /* AUTH_CMD */
2179 /* The HELO/EHLO commands are permitted to appear in the middle of a
2180 session as well as at the beginning. They have the effect of a reset in
2181 addition to their other functions. Their absence at the start cannot be
2182 taken to be an error.
2186 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2187 or 502 failure replies MUST be returned as appropriate. The SMTP
2188 server MUST stay in the same state after transmitting these replies
2189 that it was in before the EHLO was received.
2191 Therefore, we do not do the reset until after checking the command for
2192 acceptability. This change was made for Exim release 4.11. Previously
2193 it did the reset first. */
2204 HELO_EHLO: /* Common code for HELO and EHLO */
2205 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2206 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2208 /* Reject the HELO if its argument was invalid or non-existent. A
2209 successful check causes the argument to be saved in malloc store. */
2211 if (!check_helo(smtp_data))
2213 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2215 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2216 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2217 (*smtp_data == 0)? US"(no argument given)" :
2218 string_printing(smtp_data));
2220 if (++synprot_error_count > smtp_max_synprot_errors)
2222 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2223 "syntax or protocol errors (last command was \"%s\")",
2224 host_and_ident(FALSE), cmd_buffer);
2231 /* If sender_host_unknown is true, we have got here via the -bs interface,
2232 not called from inetd. Otherwise, we are running an IP connection and the
2233 host address will be set. If the helo name is the primary name of this
2234 host and we haven't done a reverse lookup, force one now. If helo_required
2235 is set, ensure that the HELO name matches the actual host. If helo_verify
2236 is set, do the same check, but softly. */
2238 if (!sender_host_unknown)
2240 BOOL old_helo_verified = helo_verified;
2241 uschar *p = smtp_data;
2243 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2246 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2247 because otherwise the log can be confusing. */
2249 if (sender_host_name == NULL &&
2250 (deliver_domain = sender_helo_name, /* set $domain */
2251 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2252 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2253 (void)host_name_lookup();
2255 /* Rebuild the fullhost info to include the HELO name (and the real name
2256 if it was looked up.) */
2258 host_build_sender_fullhost(); /* Rebuild */
2259 set_process_info("handling%s incoming connection from %s",
2260 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2262 /* Verify if configured. This doesn't give much security, but it does
2263 make some people happy to be able to do it. Note that HELO is legitimately
2264 allowed to quote an address literal. Allow for IPv6 ::ffff: literals. */
2266 helo_verified = FALSE;
2267 if (helo_required || helo_verify)
2269 BOOL tempfail = FALSE;
2271 HDEBUG(D_receive) debug_printf("verifying %s %s\n", hello,
2273 if (sender_helo_name[0] == '[')
2275 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2276 Ustrlen(sender_host_address)) == 0;
2281 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2282 helo_verified = Ustrncmp(sender_helo_name + 1,
2283 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2288 { if (helo_verified) debug_printf("matched host address\n"); }
2291 /* Do a reverse lookup if one hasn't already given a positive or
2292 negative response. If that fails, or the name doesn't match, try
2293 checking with a forward lookup. */
2297 if (sender_host_name == NULL && !host_lookup_failed)
2298 tempfail = host_name_lookup() == DEFER;
2300 /* If a host name is known, check it and all its aliases. */
2302 if (sender_host_name != NULL)
2304 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2308 HDEBUG(D_receive) debug_printf("matched host name\n");
2312 uschar **aliases = sender_host_aliases;
2313 while (*aliases != NULL)
2315 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2316 if (helo_verified) break;
2321 debug_printf("matched alias %s\n", *(--aliases));
2326 /* Final attempt: try a forward lookup of the helo name */
2332 h.name = sender_helo_name;
2336 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2338 rc = host_find_byname(&h, NULL, NULL, TRUE);
2339 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2344 if (Ustrcmp(hh->address, sender_host_address) == 0)
2346 helo_verified = TRUE;
2348 debug_printf("IP address for %s matches calling address\n",
2358 /* Verification failed. A temporary lookup failure gives a temporary
2365 smtp_printf("%d %s argument does not match calling host\r\n",
2366 tempfail? 451 : 550, hello);
2367 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2368 tempfail? "temporarily " : "",
2369 hello, sender_helo_name, host_and_ident(FALSE));
2370 helo_verified = old_helo_verified;
2371 break; /* End of HELO/EHLO processing */
2373 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2374 "helo_try_verify_hosts\n", hello);
2379 #ifdef EXPERIMENTAL_SPF
2380 /* set up SPF context */
2381 spf_init(sender_helo_name, sender_host_address);
2384 /* Apply an ACL check if one is defined */
2386 if (acl_smtp_helo != NULL)
2388 rc = acl_check(ACL_WHERE_HELO, smtp_data, acl_smtp_helo, &user_msg,
2392 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2393 sender_helo_name = NULL;
2394 host_build_sender_fullhost(); /* Rebuild */
2399 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2400 abandoning any previous message. */
2402 received_protocol = (esmtp?
2404 ((sender_host_authenticated != NULL)? pauthed : 0) +
2405 ((tls_active >= 0)? pcrpted : 0)]
2407 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2409 ((sender_host_address != NULL)? pnlocal : 0);
2411 smtp_reset(reset_point);
2414 /* Generate an OK reply, including the ident if present, and also
2415 the IP address if present. Reflecting back the ident is intended
2416 as a deterrent to mail forgers. For maximum efficiency, and also
2417 because some broken systems expect each response to be in a single
2418 packet, arrange that it is sent in one write(). */
2420 auth_advertised = FALSE;
2421 pipelining_advertised = FALSE;
2423 tls_advertised = FALSE;
2426 s = string_sprintf("250 %s Hello %s%s%s",
2427 smtp_active_hostname,
2428 (sender_ident == NULL)? US"" : sender_ident,
2429 (sender_ident == NULL)? US"" : US" at ",
2430 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2435 if (sender_host_address != NULL)
2437 s = string_cat(s, &size, &ptr, US" [", 2);
2438 s = string_cat(s, &size, &ptr, sender_host_address,
2439 Ustrlen(sender_host_address));
2440 s = string_cat(s, &size, &ptr, US"]", 1);
2443 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2445 /* If we received EHLO, we must create a multiline response which includes
2446 the functions supported. */
2452 /* I'm not entirely happy with this, as an MTA is supposed to check
2453 that it has enough room to accept a message of maximum size before
2454 it sends this. However, there seems little point in not sending it.
2455 The actual size check happens later at MAIL FROM time. By postponing it
2456 till then, VRFY and EXPN can be used after EHLO when space is short. */
2458 if (thismessage_size_limit > 0)
2460 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2461 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2465 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2468 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2469 clean; if it has an 8-bit character in its hand, it just sends it. It
2470 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2471 However, some users want this option simply in order to stop MUAs
2472 mangling messages that contain top-bit-set characters. It is therefore
2473 provided as an option. */
2475 if (accept_8bitmime)
2476 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2478 /* Advertise ETRN if there's an ACL checking whether a host is
2479 permitted to issue it; a check is made when any host actually tries. */
2481 if (acl_smtp_etrn != NULL)
2483 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2486 /* Advertise EXPN if there's an ACL checking whether a host is
2487 permitted to issue it; a check is made when any host actually tries. */
2489 if (acl_smtp_expn != NULL)
2491 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2494 /* Exim is quite happy with pipelining, so let the other end know that
2495 it is safe to use it, unless advertising is disabled. */
2497 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2499 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2500 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2501 pipelining_advertised = TRUE;
2504 /* If any server authentication mechanisms are configured, advertise
2505 them if the current host is in auth_advertise_hosts. The problem with
2506 advertising always is that some clients then require users to
2507 authenticate (and aren't configurable otherwise) even though it may not
2508 be necessary (e.g. if the host is in host_accept_relay).
2510 RFC 2222 states that SASL mechanism names contain only upper case
2511 letters, so output the names in upper case, though we actually recognize
2512 them in either case in the AUTH command. */
2516 if (verify_check_host(&auth_advertise_hosts) == OK)
2520 for (au = auths; au != NULL; au = au->next)
2522 if (au->server && (au->advertise_condition == NULL ||
2523 expand_check_condition(au->advertise_condition, au->name,
2524 US"authenticator")))
2529 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2531 auth_advertised = TRUE;
2534 s = string_cat(s, &size, &ptr, US" ", 1);
2535 s = string_cat(s, &size, &ptr, au->public_name,
2536 Ustrlen(au->public_name));
2537 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2538 au->advertised = TRUE;
2540 else au->advertised = FALSE;
2542 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2546 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2547 if it has been included in the binary, and the host matches
2548 tls_advertise_hosts. We must *not* advertise if we are already in a
2549 secure connection. */
2552 if (tls_active < 0 &&
2553 verify_check_host(&tls_advertise_hosts) != FAIL)
2555 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2556 tls_advertised = TRUE;
2560 /* Finish off the multiline reply with one that is always available. */
2562 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2565 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2571 if (tls_active >= 0) (void)tls_write(s, ptr); else
2574 fwrite(s, 1, ptr, smtp_out);
2575 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2577 break; /* HELO/EHLO */
2580 /* The MAIL command requires an address as an operand. All we do
2581 here is to parse it for syntactic correctness. The form "<>" is
2582 a special case which converts into an empty string. The start/end
2583 pointers in the original are not used further for this address, as
2584 it is the canonical extracted address which is all that is kept. */
2587 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2588 was_rej_mail = TRUE; /* Reset if accepted */
2590 if (helo_required && !helo_seen)
2592 smtp_printf("503 HELO or EHLO required\r\n");
2593 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2594 "HELO/EHLO given", host_and_ident(FALSE));
2598 if (sender_address != NULL)
2600 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2601 US"sender already given");
2605 if (smtp_data[0] == 0)
2607 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2608 US"MAIL must have an address operand");
2612 /* Check to see if the limit for messages per connection would be
2613 exceeded by accepting further messages. */
2615 if (smtp_accept_max_per_connection > 0 &&
2616 smtp_mailcmd_count > smtp_accept_max_per_connection)
2618 smtp_printf("421 too many messages in this connection\r\n");
2619 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2620 "messages in one connection", host_and_ident(TRUE));
2624 /* Reset for start of message - even if this is going to fail, we
2625 obviously need to throw away any previous data. */
2627 smtp_reset(reset_point);
2629 sender_data = recipient_data = NULL;
2631 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2635 uschar *name, *value, *end;
2636 unsigned long int size;
2638 if (!extract_option(&name, &value)) break;
2640 /* Handle SIZE= by reading the value. We don't do the check till later,
2641 in order to be able to log the sender address on failure. */
2643 if (strcmpic(name, US"SIZE") == 0 &&
2644 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2646 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2648 message_size = (int)size;
2651 /* If this session was initiated with EHLO and accept_8bitmime is set,
2652 Exim will have indicated that it supports the BODY=8BITMIME option. In
2653 fact, it does not support this according to the RFCs, in that it does not
2654 take any special action for forwarding messages containing 8-bit
2655 characters. That is why accept_8bitmime is not the default setting, but
2656 some sites want the action that is provided. We recognize both "8BITMIME"
2657 and "7BIT" as body types, but take no action. */
2659 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2660 (strcmpic(value, US"8BITMIME") == 0 ||
2661 strcmpic(value, US"7BIT") == 0)) {}
2663 /* Handle the AUTH extension. If the value given is not "<>" and either
2664 the ACL says "yes" or there is no ACL but the sending host is
2665 authenticated, we set it up as the authenticated sender. However, if the
2666 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2667 the condition is met. The value of AUTH is an xtext, which means that +,
2668 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2671 else if (strcmpic(name, US"AUTH") == 0)
2673 if (Ustrcmp(value, "<>") != 0)
2678 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2680 /* Put back terminator overrides for error message */
2683 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2684 US"invalid data for AUTH");
2688 if (acl_smtp_mailauth == NULL)
2690 ignore_msg = US"client not authenticated";
2691 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2695 ignore_msg = US"rejected by ACL";
2696 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2697 &user_msg, &log_msg);
2703 if (authenticated_by == NULL ||
2704 authenticated_by->mail_auth_condition == NULL ||
2705 expand_check_condition(authenticated_by->mail_auth_condition,
2706 authenticated_by->name, US"authenticator"))
2707 break; /* Accept the AUTH */
2709 ignore_msg = US"server_mail_auth_condition failed";
2710 if (authenticated_id != NULL)
2711 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2712 ignore_msg, authenticated_id);
2717 authenticated_sender = NULL;
2718 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2719 value, host_and_ident(TRUE), ignore_msg);
2722 /* Should only get DEFER or ERROR here. Put back terminator
2723 overrides for error message */
2728 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2735 /* Unknown option. Stick back the terminator characters and break
2736 the loop. An error for a malformed address will occur. */
2746 /* If we have passed the threshold for rate limiting, apply the current
2747 delay, and update it for next time, provided this is a limited host. */
2749 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2750 verify_check_host(&smtp_ratelimit_hosts) == OK)
2752 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2753 smtp_delay_mail/1000.0);
2754 millisleep((int)smtp_delay_mail);
2755 smtp_delay_mail *= smtp_rlm_factor;
2756 if (smtp_delay_mail > (double)smtp_rlm_limit)
2757 smtp_delay_mail = (double)smtp_rlm_limit;
2760 /* Now extract the address, first applying any SMTP-time rewriting. The
2761 TRUE flag allows "<>" as a sender address. */
2763 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2764 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2765 global_rewrite_rules) : smtp_data;
2767 /* rfc821_domains = TRUE; << no longer needed */
2769 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2771 /* rfc821_domains = FALSE; << no longer needed */
2773 if (raw_sender == NULL)
2775 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2779 sender_address = raw_sender;
2781 /* If there is a configured size limit for mail, check that this message
2782 doesn't exceed it. The check is postponed to this point so that the sender
2785 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2787 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2788 log_write(L_size_reject,
2789 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2790 "message too big: size%s=%d max=%d",
2792 host_and_ident(TRUE),
2793 (message_size == INT_MAX)? ">" : "",
2795 thismessage_size_limit);
2796 sender_address = NULL;
2800 /* Check there is enough space on the disk unless configured not to.
2801 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2802 plus the current message - i.e. we accept the message only if it won't
2803 reduce the space below the threshold. Add 5000 to the size to allow for
2804 overheads such as the Received: line and storing of recipients, etc.
2805 By putting the check here, even when SIZE is not given, it allow VRFY
2806 and EXPN etc. to be used when space is short. */
2808 if (!receive_check_fs(
2809 (smtp_check_spool_space && message_size >= 0)?
2810 message_size + 5000 : 0))
2812 smtp_printf("452 Space shortage, please try later\r\n");
2813 sender_address = NULL;
2817 /* If sender_address is unqualified, reject it, unless this is a locally
2818 generated message, or the sending host or net is permitted to send
2819 unqualified addresses - typically local machines behaving as MUAs -
2820 in which case just qualify the address. The flag is set above at the start
2821 of the SMTP connection. */
2823 if (sender_domain == 0 && sender_address[0] != 0)
2825 if (allow_unqualified_sender)
2827 sender_domain = Ustrlen(sender_address) + 1;
2828 sender_address = rewrite_address_qualify(sender_address, FALSE);
2829 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2834 smtp_printf("501 %s: sender address must contain a domain\r\n",
2836 log_write(L_smtp_syntax_error,
2837 LOG_MAIN|LOG_REJECT,
2838 "unqualified sender rejected: <%s> %s%s",
2840 host_and_ident(TRUE),
2842 sender_address = NULL;
2847 /* Apply an ACL check if one is defined, before responding */
2849 rc = (acl_smtp_mail == NULL)? OK :
2850 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2852 if (rc == OK || rc == DISCARD)
2854 smtp_printf("250 OK\r\n");
2855 smtp_delay_rcpt = smtp_rlr_base;
2856 recipients_discarded = (rc == DISCARD);
2857 was_rej_mail = FALSE;
2862 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2863 sender_address = NULL;
2868 /* The RCPT command requires an address as an operand. All we do
2869 here is to parse it for syntactic correctness. There may be any number
2870 of RCPT commands, specifying multiple senders. We build them all into
2871 a data structure that is in argc/argv format. The start/end values
2872 given by parse_extract_address are not used, as we keep only the
2873 extracted address. */
2879 /* There must be a sender address; if the sender was rejected and
2880 pipelining was advertised, we assume the client was pipelining, and do not
2881 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2882 get the same treatment. */
2884 if (sender_address == NULL)
2886 if (pipelining_advertised && last_was_rej_mail)
2888 smtp_printf("503 sender not yet given\r\n");
2889 was_rej_mail = TRUE;
2893 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2894 US"sender not yet given");
2895 was_rcpt = FALSE; /* Not a valid RCPT */
2901 /* Check for an operand */
2903 if (smtp_data[0] == 0)
2905 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2906 US"RCPT must have an address operand");
2911 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2912 as a recipient address */
2914 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2915 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2916 global_rewrite_rules) : smtp_data;
2918 /* rfc821_domains = TRUE; << no longer needed */
2919 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2920 &recipient_domain, FALSE);
2921 /* rfc821_domains = FALSE; << no longer needed */
2923 if (recipient == NULL)
2925 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2930 /* If the recipient address is unqualified, reject it, unless this is a
2931 locally generated message. However, unqualified addresses are permitted
2932 from a configured list of hosts and nets - typically when behaving as
2933 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2934 really. The flag is set at the start of the SMTP connection.
2936 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2937 assumed this meant "reserved local part", but the revision of RFC 821 and
2938 friends now makes it absolutely clear that it means *mailbox*. Consequently
2939 we must always qualify this address, regardless. */
2941 if (recipient_domain == 0)
2943 if (allow_unqualified_recipient ||
2944 strcmpic(recipient, US"postmaster") == 0)
2946 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2948 recipient_domain = Ustrlen(recipient) + 1;
2949 recipient = rewrite_address_qualify(recipient, TRUE);
2954 smtp_printf("501 %s: recipient address must contain a domain\r\n",
2956 log_write(L_smtp_syntax_error,
2957 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
2958 "<%s> %s%s", recipient, host_and_ident(TRUE),
2964 /* Check maximum allowed */
2966 if (rcpt_count > recipients_max && recipients_max > 0)
2968 if (recipients_max_reject)
2971 smtp_printf("552 too many recipients\r\n");
2973 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
2974 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
2979 smtp_printf("452 too many recipients\r\n");
2981 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
2982 "temporarily rejected: sender=<%s> %s", sender_address,
2983 host_and_ident(TRUE));
2990 /* If we have passed the threshold for rate limiting, apply the current
2991 delay, and update it for next time, provided this is a limited host. */
2993 if (rcpt_count > smtp_rlr_threshold &&
2994 verify_check_host(&smtp_ratelimit_hosts) == OK)
2996 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
2997 smtp_delay_rcpt/1000.0);
2998 millisleep((int)smtp_delay_rcpt);
2999 smtp_delay_rcpt *= smtp_rlr_factor;
3000 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3001 smtp_delay_rcpt = (double)smtp_rlr_limit;
3004 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3005 for them. Otherwise, check the access control list for this recipient. */
3007 rc = recipients_discarded? DISCARD :
3008 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3010 /* The ACL was happy */
3014 smtp_printf("250 Accepted\r\n");
3015 receive_add_recipient(recipient, -1);
3018 /* The recipient was discarded */
3020 else if (rc == DISCARD)
3022 smtp_printf("250 Accepted\r\n");
3025 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3026 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3027 (sender_address_unrewritten != NULL)?
3028 sender_address_unrewritten : sender_address,
3029 smtp_data, recipients_discarded? "MAIL" : "RCPT",
3030 (log_msg == NULL)? US"" : US": ",
3031 (log_msg == NULL)? US"" : log_msg);
3034 /* Either the ACL failed the address, or it was deferred. */
3038 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3039 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3044 /* The DATA command is legal only if it follows successful MAIL FROM
3045 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3046 not counted as a protocol error if it follows RCPT (which must have been
3047 rejected if there are no recipients.) This function is complete when a
3048 valid DATA command is encountered.
3050 Note concerning the code used: RFC 2821 says this:
3052 - If there was no MAIL, or no RCPT, command, or all such commands
3053 were rejected, the server MAY return a "command out of sequence"
3054 (503) or "no valid recipients" (554) reply in response to the
3057 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3058 because it is the same whether pipelining is in use or not. */
3061 if (!discarded && recipients_count <= 0)
3063 if (pipelining_advertised && last_was_rcpt)
3064 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3066 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3067 US"valid RCPT command must precede DATA");
3071 if (toomany && recipients_max_reject)
3073 sender_address = NULL; /* This will allow a new MAIL without RSET */
3074 sender_address_unrewritten = NULL;
3075 smtp_printf("554 Too many recipients\r\n");
3079 if (acl_smtp_predata == NULL) rc = OK; else
3081 enable_dollar_recipients = TRUE;
3082 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3084 enable_dollar_recipients = FALSE;
3089 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3091 message_ended = END_NOTENDED; /* Indicate in middle of data */
3094 /* Either the ACL failed the address, or it was deferred. */
3097 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3103 rc = acl_check(ACL_WHERE_VRFY, smtp_data, acl_smtp_vrfy, &user_msg,
3106 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3112 /* rfc821_domains = TRUE; << no longer needed */
3113 address = parse_extract_address(smtp_data, &errmess, &start, &end,
3114 &recipient_domain, FALSE);
3115 /* rfc821_domains = FALSE; << no longer needed */
3117 if (address == NULL)
3118 s = string_sprintf("501 %s", errmess);
3121 address_item *addr = deliver_make_addr(address, FALSE);
3122 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3123 -1, -1, NULL, NULL, NULL))
3126 s = string_sprintf("250 <%s> is deliverable", address);
3130 s = (addr->message != NULL)?
3131 string_sprintf("451 <%s> %s", address, addr->message) :
3132 string_sprintf("451 Cannot resolve <%s> at this time", address);
3136 s = (addr->message != NULL)?
3137 string_sprintf("550 <%s> %s", address, addr->message) :
3138 string_sprintf("550 <%s> is not deliverable", address);
3139 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3140 smtp_data, host_and_ident(TRUE));
3145 smtp_printf("%s\r\n", s);
3151 rc = acl_check(ACL_WHERE_EXPN, smtp_data, acl_smtp_expn, &user_msg,
3154 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3157 BOOL save_log_testing_mode = log_testing_mode;
3158 address_test_mode = log_testing_mode = TRUE;
3159 (void) verify_address(deliver_make_addr(smtp_data, FALSE), smtp_out,
3160 vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1, NULL, NULL,
3162 address_test_mode = FALSE;
3163 log_testing_mode = save_log_testing_mode; /* true for -bh */
3171 if (!tls_advertised)
3173 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3174 US"STARTTLS command used when not advertised");
3178 /* Apply an ACL check if one is defined */
3180 if (acl_smtp_starttls != NULL)
3182 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3186 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3191 /* RFC 2487 is not clear on when this command may be sent, though it
3192 does state that all information previously obtained from the client
3193 must be discarded if a TLS session is started. It seems reasonble to
3194 do an implied RSET when STARTTLS is received. */
3196 incomplete_transaction_log(US"STARTTLS");
3197 smtp_reset(reset_point);
3199 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3201 /* Attempt to start up a TLS session, and if successful, discard all
3202 knowledge that was obtained previously. At least, that's what the RFC says,
3203 and that's what happens by default. However, in order to work round YAEB,
3204 there is an option to remember the esmtp state. Sigh.
3206 We must allow for an extra EHLO command and an extra AUTH command after
3207 STARTTLS that don't add to the nonmail command count. */
3209 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3211 if (!tls_remember_esmtp)
3212 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3213 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3214 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3215 if (sender_helo_name != NULL)
3217 store_free(sender_helo_name);
3218 sender_helo_name = NULL;
3219 host_build_sender_fullhost(); /* Rebuild */
3220 set_process_info("handling incoming TLS connection from %s",
3221 host_and_ident(FALSE));
3223 received_protocol = (esmtp?
3224 protocols[pextend + pcrpted +
3225 ((sender_host_authenticated != NULL)? pauthed : 0)]
3227 protocols[pnormal + pcrpted])
3229 ((sender_host_address != NULL)? pnlocal : 0);
3231 sender_host_authenticated = NULL;
3232 authenticated_id = NULL;
3233 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3234 DEBUG(D_tls) debug_printf("TLS active\n");
3235 break; /* Successful STARTTLS */
3238 /* Some local configuration problem was discovered before actually trying
3239 to do a TLS handshake; give a temporary error. */
3241 else if (rc == DEFER)
3243 smtp_printf("454 TLS currently unavailable\r\n");
3247 /* Hard failure. Reject everything except QUIT or closed connection. One
3248 cause for failure is a nested STARTTLS, in which case tls_active remains
3249 set, but we must still reject all incoming commands. */
3251 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3254 switch(smtp_read_command(FALSE))
3257 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3258 smtp_get_connection_info());
3263 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3264 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3265 smtp_get_connection_info());
3270 smtp_printf("554 Security failure\r\n");
3279 /* The ACL for QUIT is provided for gathering statistical information or
3280 similar; it does not affect the response code, but it can supply a custom
3284 incomplete_transaction_log(US"QUIT");
3286 if (acl_smtp_quit != NULL)
3288 rc = acl_check(ACL_WHERE_QUIT, US"", acl_smtp_quit,&user_msg,&log_msg);
3290 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3293 else user_msg = NULL;
3295 if (user_msg == NULL)
3296 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3298 smtp_printf("221 %s\r\n", user_msg);
3305 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3306 smtp_get_connection_info());
3311 incomplete_transaction_log(US"RSET");
3312 smtp_reset(reset_point);
3314 smtp_printf("250 Reset OK\r\n");
3315 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3320 smtp_printf("250 OK\r\n");
3324 /* Show ETRN/EXPN/VRFY if there's
3325 an ACL for checking hosts; if actually used, a check will be done for
3329 smtp_printf("214-Commands supported:\r\n");
3333 Ustrcat(buffer, " AUTH");
3335 Ustrcat(buffer, " STARTTLS");
3337 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3338 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3339 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3340 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3341 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3342 smtp_printf("214%s\r\n", buffer);
3348 incomplete_transaction_log(US"connection lost");
3349 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3351 /* Don't log by default unless in the middle of a message, as some mailers
3352 just drop the call rather than sending QUIT, and it clutters up the logs.
3355 if (sender_address != NULL || recipients_count > 0)
3356 log_write(L_lost_incoming_connection,
3358 "unexpected %s while reading SMTP command from %s%s",
3359 sender_host_unknown? "EOF" : "disconnection",
3360 host_and_ident(FALSE), smtp_read_error);
3362 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3363 smtp_get_connection_info(), smtp_read_error);
3370 if (sender_address != NULL)
3372 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3373 US"ETRN is not permitted inside a transaction");
3377 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_data,
3378 host_and_ident(FALSE));
3380 rc = acl_check(ACL_WHERE_ETRN, smtp_data, acl_smtp_etrn, &user_msg,
3384 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3388 /* Compute the serialization key for this command. */
3390 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_data);
3392 /* If a command has been specified for running as a result of ETRN, we
3393 permit any argument to ETRN. If not, only the # standard form is permitted,
3394 since that is strictly the only kind of ETRN that can be implemented
3395 according to the RFC. */
3397 if (smtp_etrn_command != NULL)
3401 etrn_command = smtp_etrn_command;
3402 deliver_domain = smtp_data;
3403 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3404 US"ETRN processing", &error);
3405 deliver_domain = NULL;
3408 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3410 smtp_printf("458 Internal failure\r\n");
3415 /* Else set up to call Exim with the -R option. */
3419 if (*smtp_data++ != '#')
3421 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3422 US"argument must begin with #");
3425 etrn_command = US"exim -R";
3426 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3430 /* If we are host-testing, don't actually do anything. */
3436 debug_printf("ETRN command is: %s\n", etrn_command);
3437 debug_printf("ETRN command execution skipped\n");
3439 smtp_printf("250 OK\r\n");
3444 /* If ETRN queue runs are to be serialized, check the database to
3445 ensure one isn't already running. */
3447 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3449 smtp_printf("458 Already processing %s\r\n", smtp_data);
3453 /* Fork a child process and run the command. We don't want to have to
3454 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3455 forking. It should be set that way anyway for external incoming SMTP,
3456 but we save and restore to be tidy. If serialization is required, we
3457 actually run the command in yet another process, so we can wait for it
3458 to complete and then remove the serialization lock. */
3460 oldsignal = signal(SIGCHLD, SIG_IGN);
3462 if ((pid = fork()) == 0)
3464 smtp_input = FALSE; /* This process is not associated with the */
3465 fclose(smtp_in); /* SMTP call any more. */
3468 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3470 /* If not serializing, do the exec right away. Otherwise, fork down
3471 into another process. */
3473 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3475 DEBUG(D_exec) debug_print_argv(argv);
3476 exim_nullstd(); /* Ensure std{in,out,err} exist */
3477 execv(CS argv[0], (char *const *)argv);
3478 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3479 etrn_command, strerror(errno));
3480 _exit(EXIT_FAILURE); /* paranoia */
3483 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3484 is, we are in the first subprocess, after forking again. All we can do
3485 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3486 complete, before removing the serialization. */
3489 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3490 "failed: %s", strerror(errno));
3494 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3496 (void)wait(&status);
3497 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3501 enq_end(etrn_serialize_key);
3502 _exit(EXIT_SUCCESS);
3505 /* Back in the top level SMTP process. Check that we started a subprocess
3506 and restore the signal state. */
3510 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3512 smtp_printf("458 Unable to fork process\r\n");
3513 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3515 else smtp_printf("250 OK\r\n");
3517 signal(SIGCHLD, oldsignal);
3522 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3523 US"unexpected argument data");
3527 /* This currently happens only for NULLs, but could be extended. */
3530 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3531 US"NULL character(s) present (shown as '?')");
3532 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3537 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3538 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3539 c = smtp_inend - smtp_inptr;
3540 if (c > 150) c = 150;
3542 incomplete_transaction_log(US"sync failure");
3543 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: "
3544 "synchronization error "
3545 "(next input sent too soon: pipelining was%s advertised): "
3546 "rejected \"%s\" %s next input=\"%s\"",
3547 pipelining_advertised? "" : " not",
3548 cmd_buffer, host_and_ident(TRUE),
3549 string_printing(smtp_inptr));
3550 smtp_printf("554 SMTP synchronization error\r\n");
3551 done = 1; /* Pretend eof - drops connection */
3555 case TOO_MANY_NONMAIL_CMD:
3556 incomplete_transaction_log(US"too many non-mail commands");
3557 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3558 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
3559 smtp_data - cmd_buffer, cmd_buffer);
3560 smtp_printf("554 Too many nonmail commands\r\n");
3561 done = 1; /* Pretend eof - drops connection */
3566 if (unknown_command_count++ >= smtp_max_unknown_commands)
3568 log_write(L_smtp_syntax_error, LOG_MAIN,
3569 "SMTP syntax error in \"%s\" %s %s",
3570 string_printing(cmd_buffer), host_and_ident(TRUE),
3571 US"unrecognized command");
3572 incomplete_transaction_log(US"unrecognized command");
3573 smtp_printf("500 Too many unrecognized commands\r\n");
3575 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3576 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3580 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3581 US"unrecognized command");
3585 /* This label is used by goto's inside loops that want to break out to
3586 the end of the command-processing loop. */
3589 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3590 last_was_rcpt = was_rcpt; /* protocol error handling */
3594 return done - 2; /* Convert yield values */
3597 /* End of smtp_in.c */