1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.9 2005/01/13 16:15:53 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 && Ustrcmp(sender_host_address, "127.0.0.2") == 0)
1131 /* Default values for certain variables */
1133 helo_seen = esmtp = helo_accept_junk = FALSE;
1134 count_nonmail = TRUE_UNSET;
1135 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1136 smtp_delay_mail = smtp_rlm_base;
1137 auth_advertised = FALSE;
1138 pipelining_advertised = FALSE;
1139 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1141 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1143 sender_host_authenticated = NULL;
1144 authenticated_by = NULL;
1147 tls_cipher = tls_peerdn = NULL;
1148 tls_advertised = FALSE;
1151 /* Reset ACL connection variables */
1153 for (i = 0; i < ACL_C_MAX; i++) acl_var[i] = NULL;
1155 cmd_buffer = (uschar *)malloc(cmd_buffer_size + 1); /* allow for trailing 0 */
1156 if (cmd_buffer == NULL)
1157 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1158 "malloc() failed for SMTP command buffer");
1160 /* For batched input, the protocol setting can be overridden from the
1161 command line by a trusted caller. */
1163 if (smtp_batched_input)
1165 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1168 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1169 reset later if any of EHLO/AUTH/STARTTLS are received. */
1173 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1175 /* Set up the buffer for inputting using direct read() calls, and arrange to
1176 call the local functions instead of the standard C ones. */
1178 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1179 if (smtp_inbuffer == NULL)
1180 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1181 receive_getc = smtp_getc;
1182 receive_ungetc = smtp_ungetc;
1183 receive_feof = smtp_feof;
1184 receive_ferror = smtp_ferror;
1185 smtp_inptr = smtp_inend = smtp_inbuffer;
1186 smtp_had_eof = smtp_had_error = 0;
1188 /* Set up the message size limit; this may be host-specific */
1190 thismessage_size_limit = expand_string_integer(message_size_limit);
1191 if (thismessage_size_limit < 0)
1193 if (thismessage_size_limit == -1)
1194 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1195 "%s", expand_string_message);
1197 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1198 "%s", expand_string_message);
1199 smtp_closedown(US"Temporary local problem - please try later");
1203 /* When a message is input locally via the -bs or -bS options, sender_host_
1204 unknown is set unless -oMa was used to force an IP address, in which case it
1205 is checked like a real remote connection. When -bs is used from inetd, this
1206 flag is not set, causing the sending host to be checked. The code that deals
1207 with IP source routing (if configured) is never required for -bs or -bS and
1208 the flag sender_host_notsocket is used to suppress it.
1210 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1211 reserve for certain hosts and/or networks. */
1213 if (!sender_host_unknown)
1216 BOOL reserved_host = FALSE;
1218 /* Look up IP options (source routing info) on the socket if this is not an
1219 -oMa "host", and if any are found, log them and drop the connection.
1221 Linux (and others now, see below) is different to everyone else, so there
1222 has to be some conditional compilation here. Versions of Linux before 2.1.15
1223 used a structure whose name was "options". Somebody finally realized that
1224 this name was silly, and it got changed to "ip_options". I use the
1225 newer name here, but there is a fudge in the script that sets up os.h
1226 to define a macro in older Linux systems.
1228 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1229 glibc 2, which has chosen ip_opts for the structure name. This is now
1230 really a glibc thing rather than a Linux thing, so the condition name
1231 has been changed to reflect this. It is relevant also to GNU/Hurd.
1233 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1234 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1235 a special macro defined in the os.h file.
1237 Some DGUX versions on older hardware appear not to support IP options at
1238 all, so there is now a general macro which can be set to cut out this
1241 How to do this properly in IPv6 is not yet known. */
1243 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1245 #ifdef GLIBC_IP_OPTIONS
1246 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1251 #elif defined DARWIN_IP_OPTIONS
1257 if (!host_checking && !sender_host_notsocket)
1260 SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1261 struct ip_options *ipopt = store_get(optlen);
1263 struct ip_opts ipoptblock;
1264 struct ip_opts *ipopt = &ipoptblock;
1265 SOCKLEN_T optlen = sizeof(ipoptblock);
1267 struct ipoption ipoptblock;
1268 struct ipoption *ipopt = &ipoptblock;
1269 SOCKLEN_T optlen = sizeof(ipoptblock);
1272 /* Occasional genuine failures of getsockopt() have been seen - for
1273 example, "reset by peer". Therefore, just log and give up on this
1274 call, unless the error is ENOPROTOOPT. This error is given by systems
1275 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1276 of writing. So for that error, carry on - we just can't do an IP options
1279 DEBUG(D_receive) debug_printf("checking for IP options\n");
1281 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1284 if (errno != ENOPROTOOPT)
1286 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1287 host_and_ident(FALSE), strerror(errno));
1288 smtp_printf("451 SMTP service not available\r\n");
1293 /* Deal with any IP options that are set. On the systems I have looked at,
1294 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1295 more logging data than will fit in big_buffer. Nevertheless, after somebody
1296 questioned this code, I've added in some paranoid checking. */
1298 else if (optlen > 0)
1300 uschar *p = big_buffer;
1301 uschar *pend = big_buffer + big_buffer_size;
1302 uschar *opt, *adptr;
1304 struct in_addr addr;
1307 uschar *optstart = (uschar *)(ipopt->__data);
1309 uschar *optstart = (uschar *)(ipopt->ip_opts);
1311 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1314 DEBUG(D_receive) debug_printf("IP options exist\n");
1316 Ustrcpy(p, "IP options on incoming call:");
1319 for (opt = optstart; opt != NULL &&
1320 opt < (uschar *)(ipopt) + optlen;)
1334 if (!string_format(p, pend-p, " %s [@%s",
1335 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1337 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1339 inet_ntoa(ipopt->ip_dst)))
1341 inet_ntoa(ipopt->ipopt_dst)))
1349 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1351 while (optcount-- > 0)
1353 memcpy(&addr, adptr, sizeof(addr));
1354 if (!string_format(p, pend - p - 1, "%s%s",
1355 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1361 adptr += sizeof(struct in_addr);
1370 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1373 for (i = 0; i < opt[1]; i++)
1375 sprintf(CS p, "%2.2x ", opt[i]);
1386 log_write(0, LOG_MAIN, "%s", big_buffer);
1388 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1390 log_write(0, LOG_MAIN|LOG_REJECT,
1391 "connection from %s refused (IP options)", host_and_ident(FALSE));
1393 smtp_printf("554 SMTP service not available\r\n");
1397 /* Length of options = 0 => there are no options */
1399 else DEBUG(D_receive) debug_printf("no IP options found\n");
1401 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1403 /* Set keep-alive in socket options. The option is on by default. This
1404 setting is an attempt to get rid of some hanging connections that stick in
1405 read() when the remote end (usually a dialup) goes away. */
1407 if (smtp_accept_keepalive && !sender_host_notsocket)
1408 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1410 /* If the current host matches host_lookup, set the name by doing a
1411 reverse lookup. On failure, sender_host_name will be NULL and
1412 host_lookup_failed will be TRUE. This may or may not be serious - optional
1415 if (verify_check_host(&host_lookup) == OK)
1417 (void)host_name_lookup();
1418 host_build_sender_fullhost();
1421 /* Delay this until we have the full name, if it is looked up. */
1423 set_process_info("handling incoming connection from %s",
1424 host_and_ident(FALSE));
1426 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1427 smtps port for use with older style SSL MTAs. */
1430 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1434 /* Test for explicit connection rejection */
1436 if (verify_check_host(&host_reject_connection) == OK)
1438 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1439 "from %s (host_reject_connection)", host_and_ident(FALSE));
1440 smtp_printf("554 SMTP service not available\r\n");
1444 /* Test with TCP Wrappers if so configured */
1446 #ifdef USE_TCP_WRAPPERS
1447 if (!hosts_ctl("exim",
1448 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1449 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1450 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1452 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1453 log_write(L_connection_reject,
1454 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1455 "(tcp wrappers)", host_and_ident(FALSE));
1456 smtp_printf("554 SMTP service not available\r\n");
1461 /* Check for reserved slots. Note that the count value doesn't include
1462 this process, as it gets upped in the parent process. */
1464 if (smtp_accept_max > 0 &&
1465 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1467 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1469 log_write(L_connection_reject,
1470 LOG_MAIN, "temporarily refused connection from %s: not in "
1471 "reserve list: connected=%d max=%d reserve=%d%s",
1472 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1473 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1474 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1475 "please try again later\r\n", smtp_active_hostname);
1478 reserved_host = TRUE;
1481 /* If a load level above which only messages from reserved hosts are
1482 accepted is set, check the load. For incoming calls via the daemon, the
1483 check is done in the superior process if there are no reserved hosts, to
1484 save a fork. In all cases, the load average will already be available
1485 in a global variable at this point. */
1487 if (smtp_load_reserve >= 0 &&
1488 load_average > smtp_load_reserve &&
1490 verify_check_host(&smtp_reserve_hosts) != OK)
1492 log_write(L_connection_reject,
1493 LOG_MAIN, "temporarily refused connection from %s: not in "
1494 "reserve list and load average = %.2f", host_and_ident(FALSE),
1495 (double)load_average/1000.0);
1496 smtp_printf("421 %s: Too much load; please try again later\r\n",
1497 smtp_active_hostname);
1501 /* Determine whether unqualified senders or recipients are permitted
1502 for this host. Unfortunately, we have to do this every time, in order to
1503 set the flags so that they can be inspected when considering qualifying
1504 addresses in the headers. For a site that permits no qualification, this
1505 won't take long, however. */
1507 allow_unqualified_sender =
1508 verify_check_host(&sender_unqualified_hosts) == OK;
1510 allow_unqualified_recipient =
1511 verify_check_host(&recipient_unqualified_hosts) == OK;
1513 /* Determine whether HELO/EHLO is required for this host. The requirement
1514 can be hard or soft. */
1516 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1518 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1520 /* Determine whether this hosts is permitted to send syntactic junk
1521 after a HELO or EHLO command. */
1523 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1526 /* For batch SMTP input we are now done. */
1528 if (smtp_batched_input) return TRUE;
1530 /* Run the ACL if it exists */
1532 if (acl_smtp_connect != NULL)
1535 uschar *user_msg, *log_msg;
1536 smtp_data = US"in \"connect\" ACL"; /* For logged failure message */
1537 rc = acl_check(ACL_WHERE_CONNECT, US"", acl_smtp_connect, &user_msg,
1541 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1546 /* Output the initial message for a two-way SMTP connection. It may contain
1547 newlines, which then cause a multi-line response to be given. */
1549 s = expand_string(smtp_banner);
1551 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1552 "failed: %s", smtp_banner, expand_string_message);
1554 /* Remove any terminating newlines; might as well remove trailing space too */
1557 while (p > s && isspace(p[-1])) p--;
1560 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1561 is all contained in a single IP packet. The original code wrote out the
1562 greeting using several calls to fprint/fputc, and on busy servers this could
1563 cause it to be split over more than one packet - which caused CC:Mail to fall
1564 over when it got the second part of the greeting after sending its first
1565 command. Sigh. To try to avoid this, build the complete greeting message
1566 first, and output it in one fell swoop. This gives a better chance of it
1567 ending up as a single packet. */
1569 ss = store_get(size);
1573 do /* At least once, in case we have an empty string */
1576 uschar *linebreak = Ustrchr(p, '\n');
1577 if (linebreak == NULL)
1580 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1584 len = linebreak - p;
1585 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1587 ss = string_cat(ss, &size, &ptr, p, len);
1588 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1590 if (linebreak != NULL) p++;
1594 ss[ptr] = 0; /* string_cat leaves room for this */
1596 /* Before we write the banner, check that there is no input pending, unless
1597 this synchronisation check is disabled. */
1599 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1602 struct timeval tzero;
1606 FD_SET(fileno(smtp_in), &fds);
1607 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1610 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1611 if (rc > 150) rc = 150;
1612 smtp_inbuffer[rc] = 0;
1613 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: "
1614 "synchronization error (input sent without waiting for greeting): "
1615 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1616 string_printing(smtp_inbuffer));
1617 smtp_printf("554 SMTP synchronization error\r\n");
1622 /* Now output the banner */
1624 smtp_printf("%s", ss);
1632 /*************************************************
1633 * Handle SMTP syntax and protocol errors *
1634 *************************************************/
1636 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1637 to do so. Then transmit the error response. The return value depends on the
1638 number of syntax and protocol errors in this SMTP session.
1641 type error type, given as a log flag bit
1642 code response code; <= 0 means don't send a response
1643 data data to reflect in the response (can be NULL)
1644 errmess the error message
1646 Returns: -1 limit of syntax/protocol errors NOT exceeded
1647 +1 limit of syntax/protocol errors IS exceeded
1649 These values fit in with the values of the "done" variable in the main
1650 processing loop in smtp_setup_msg(). */
1653 synprot_error(int type, int code, uschar *data, uschar *errmess)
1657 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1658 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1659 string_printing(cmd_buffer), host_and_ident(TRUE), errmess);
1661 if (++synprot_error_count > smtp_max_synprot_errors)
1664 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1665 "syntax or protocol errors (last command was \"%s\")",
1666 host_and_ident(FALSE), cmd_buffer);
1671 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1672 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1674 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1683 /*************************************************
1684 * Log incomplete transactions *
1685 *************************************************/
1687 /* This function is called after a transaction has been aborted by RSET, QUIT,
1688 connection drops or other errors. It logs the envelope information received
1689 so far in order to preserve address verification attempts.
1691 Argument: string to indicate what aborted the transaction
1696 incomplete_transaction_log(uschar *what)
1698 if (sender_address == NULL || /* No transaction in progress */
1699 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1702 /* Build list of recipients for logging */
1704 if (recipients_count > 0)
1707 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1708 for (i = 0; i < recipients_count; i++)
1709 raw_recipients[i] = recipients_list[i].address;
1710 raw_recipients_count = recipients_count;
1713 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1714 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1720 /*************************************************
1721 * Send SMTP response, possibly multiline *
1722 *************************************************/
1724 /* There are, it seems, broken clients out there that cannot handle multiline
1725 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1726 output nothing for non-final calls, and only the first line for anything else.
1730 final FALSE if the last line isn't the final line
1731 msg message text, possibly containing newlines
1737 smtp_respond(int code, BOOL final, uschar *msg)
1739 if (!final && no_multiline_responses) return;
1743 uschar *nl = Ustrchr(msg, '\n');
1746 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1749 else if (nl[1] == 0 || no_multiline_responses)
1751 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1756 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1758 while (isspace(*msg)) msg++;
1766 /*************************************************
1767 * Handle an ACL failure *
1768 *************************************************/
1770 /* This function is called when acl_check() fails. As well as calls from within
1771 this module, it is called from receive.c for an ACL after DATA. It sorts out
1772 logging the incident, and sets up the error response. A message containing
1773 newlines is turned into a multiline SMTP response, but for logging, only the
1776 There's a table of the response codes to use in globals.c, along with the table
1777 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1778 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1779 that the response should be 252 in the disabled state, because there are broken
1780 clients that try VRFY before RCPT. A 5xx response should be given only when the
1781 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1782 given on refusal, and for AUTH, 503.
1785 where where the ACL was called from
1787 user_msg a message that can be included in an SMTP response
1788 log_msg a message for logging
1790 Returns: 0 in most cases
1791 2 if the failure code was FAIL_DROP, in which case the
1792 SMTP connection should be dropped (this value fits with the
1793 "done" variable in smtp_setup_msg() below)
1797 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1799 int code = acl_wherecodes[where];
1800 BOOL drop = rc == FAIL_DROP;
1802 uschar *sender_info = US"";
1803 uschar *what = (where == ACL_WHERE_PREDATA)? US"DATA" :
1804 #ifdef WITH_CONTENT_SCAN
1805 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1807 (where == ACL_WHERE_DATA)? US"after DATA" :
1808 string_sprintf("%s %s", acl_wherenames[where], smtp_data);
1810 if (drop) rc = FAIL;
1812 /* We used to have sender_address here; however, there was a bug that was not
1813 updating sender_address after a rewrite during a verify. When this bug was
1814 fixed, sender_address at this point became the rewritten address. I'm not sure
1815 this is what should be logged, so I've changed to logging the unrewritten
1816 address to retain backward compatibility. */
1818 #ifndef WITH_CONTENT_SCAN
1819 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1821 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1824 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1825 sender_address_unrewritten : sender_address);
1828 /* If there's been a sender verification failure with a specific message, and
1829 we have not sent a response about it yet, do so now, as a preliminary line for
1830 failures, but not defers. However, log it in both cases. */
1832 if (sender_verified_failed != NULL &&
1833 !testflag(sender_verified_failed, af_sverify_told))
1835 setflag(sender_verified_failed, af_sverify_told);
1837 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1838 host_and_ident(TRUE),
1839 ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail",
1840 sender_verified_failed->address,
1841 (sender_verified_failed->message == NULL)? US"" :
1842 string_sprintf(": %s", sender_verified_failed->message));
1844 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1845 smtp_respond(code, FALSE, string_sprintf(
1846 testflag(sender_verified_failed, af_verify_pmfail)?
1847 "Postmaster verification failed while checking <%s>\n%s\n"
1848 "Several RFCs state that you are required to have a postmaster\n"
1849 "mailbox for each mail domain. This host does not accept mail\n"
1850 "from domains whose servers reject the postmaster address."
1852 testflag(sender_verified_failed, af_verify_nsfail)?
1853 "Callback setup failed while verifying <%s>\n%s\n"
1854 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1855 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1856 "RFC requirements, and stops you from receiving standard bounce\n"
1857 "messages. This host does not accept mail from domains whose servers\n"
1860 "Verification failed for <%s>\n%s",
1861 sender_verified_failed->address,
1862 sender_verified_failed->user_message));
1865 /* Sort out text for logging */
1867 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1868 lognl = Ustrchr(log_msg, '\n');
1869 if (lognl != NULL) *lognl = 0;
1871 /* Send permanent failure response to the command, but the code used isn't
1872 always a 5xx one - see comments at the start of this function. If the original
1873 rc was FAIL_DROP we drop the connection and yield 2. */
1875 if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1876 US"Administrative prohibition" : user_msg);
1878 /* Send temporary failure response to the command. Don't give any details,
1879 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1880 verb, and for a header verify when smtp_return_error_details is set.
1882 This conditional logic is all somewhat of a mess because of the odd
1883 interactions between temp_details and return_error_details. One day it should
1884 be re-implemented in a tidier fashion. */
1888 if (acl_temp_details && user_msg != NULL)
1890 if (smtp_return_error_details &&
1891 sender_verified_failed != NULL &&
1892 sender_verified_failed->message != NULL)
1894 smtp_respond(451, FALSE, sender_verified_failed->message);
1896 smtp_respond(451, TRUE, user_msg);
1899 smtp_printf("451 Temporary local problem - please try later\r\n");
1902 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
1903 Otherwise, log why it is closing if required and return 2. */
1905 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1906 host_and_ident(TRUE),
1907 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1909 if (!drop) return 0;
1911 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1912 smtp_get_connection_info());
1919 /*************************************************
1920 * Initialize for SMTP incoming message *
1921 *************************************************/
1923 /* This function conducts the initial dialogue at the start of an incoming SMTP
1924 message, and builds a list of recipients. However, if the incoming message
1925 is part of a batch (-bS option) a separate function is called since it would
1926 be messy having tests splattered about all over this function. This function
1927 therefore handles the case where interaction is occurring. The input and output
1928 files are set up in smtp_in and smtp_out.
1930 The global recipients_list is set to point to a vector of recipient_item
1931 blocks, whose number is given by recipients_count. This is extended by the
1932 receive_add_recipient() function. The global variable sender_address is set to
1933 the sender's address. The yield is +1 if a message has been successfully
1934 started, 0 if a QUIT command was encountered or the connection was refused from
1935 the particular host, or -1 if the connection was lost.
1939 Returns: > 0 message successfully started (reached DATA)
1940 = 0 QUIT read or end of file reached or call refused
1945 smtp_setup_msg(void)
1948 BOOL toomany = FALSE;
1949 BOOL discarded = FALSE;
1950 BOOL last_was_rej_mail = FALSE;
1951 BOOL last_was_rcpt = FALSE;
1952 void *reset_point = store_get(0);
1954 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
1956 /* Reset for start of new message. We allow one RSET not to be counted as a
1957 nonmail command, for those MTAs that insist on sending it between every
1958 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
1959 TLS between messages (an Exim client may do this if it has messages queued up
1960 for the host). Note: we do NOT reset AUTH at this point. */
1962 smtp_reset(reset_point);
1963 message_ended = END_NOTSTARTED;
1965 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
1966 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
1967 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
1969 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
1972 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
1974 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
1976 /* Batched SMTP is handled in a different function. */
1978 if (smtp_batched_input) return smtp_setup_batch_msg();
1980 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1981 value. The values are 2 larger than the required yield of the function. */
1986 uschar *etrn_command;
1987 uschar *etrn_serialize_key;
1989 uschar *user_msg, *log_msg;
1990 uschar *recipient = NULL;
1991 uschar *hello = NULL;
1992 uschar *set_id = NULL;
1994 BOOL was_rej_mail = FALSE;
1995 BOOL was_rcpt = FALSE;
1996 void (*oldsignal)(int);
1998 int start, end, sender_domain, recipient_domain;
2003 switch(smtp_read_command(TRUE))
2005 /* The AUTH command is not permitted to occur inside a transaction, and may
2006 occur successfully only once per connection, and then only when we've
2007 advertised it. Actually, that isn't quite true. When TLS is started, all
2008 previous information about a connection must be discarded, so a new AUTH is
2009 permitted at that time.
2011 AUTH is initially labelled as a "nonmail command" so that one occurrence
2012 doesn't get counted. We change the label here so that multiple failing
2013 AUTHS will eventually hit the nonmail threshold. */
2016 authentication_failed = TRUE;
2017 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2019 if (!auth_advertised)
2021 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2022 US"AUTH command used when not advertised");
2025 if (sender_host_authenticated != NULL)
2027 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2028 US"already authenticated");
2031 if (sender_address != NULL)
2033 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2034 US"not permitted in mail transaction");
2040 if (acl_smtp_auth != NULL)
2042 rc = acl_check(ACL_WHERE_AUTH, smtp_data, acl_smtp_auth, &user_msg,
2046 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2051 /* Find the name of the requested authentication mechanism. */
2054 while ((c = *smtp_data) != 0 && !isspace(c))
2056 if (!isalnum(c) && c != '-' && c != '_')
2058 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2059 US"invalid character in authentication mechanism name");
2065 /* If not at the end of the line, we must be at white space. Terminate the
2066 name and move the pointer on to any data that may be present. */
2068 if (*smtp_data != 0)
2071 while (isspace(*smtp_data)) smtp_data++;
2074 /* Search for an authentication mechanism which is configured for use
2075 as a server and which has been advertised. */
2077 for (au = auths; au != NULL; au = au->next)
2079 if (strcmpic(s, au->public_name) == 0 && au->server &&
2080 au->advertised) break;
2085 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2086 string_sprintf("%s authentication mechanism not supported", s));
2090 /* Run the checking code, passing the remainder of the command
2091 line as data. Initialize $0 empty. The authenticator may set up
2092 other numeric variables. Afterwards, have a go at expanding the set_id
2093 string, even if authentication failed - for bad passwords it can be useful
2094 to log the userid. On success, require set_id to expand and exist, and
2095 put it in authenticated_id. Save this in permanent store, as the working
2096 store gets reset at HELO, RSET, etc. */
2099 expand_nlength[0] = 0; /* $0 contains nothing */
2101 c = (au->info->servercode)(au, smtp_data);
2102 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2103 expand_nmax = -1; /* Reset numeric variables */
2105 /* For the non-OK cases, set up additional logging data if set_id
2110 if (set_id != NULL && *set_id != 0)
2111 set_id = string_sprintf(" (set_id=%s)", set_id);
2115 /* Switch on the result */
2120 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2122 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2123 sender_host_authenticated = au->name;
2124 authentication_failed = FALSE;
2126 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2127 ((sender_host_address != NULL)? pnlocal : 0);
2128 s = ss = US"235 Authentication succeeded";
2129 authenticated_by = au;
2133 /* Authentication succeeded, but we failed to expand the set_id string.
2134 Treat this as a temporary error. */
2136 auth_defer_msg = expand_string_message;
2140 s = string_sprintf("435 Unable to authenticate at present%s",
2141 auth_defer_user_msg);
2142 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2143 set_id, auth_defer_msg);
2147 s = ss = US"501 Invalid base64 data";
2151 s = ss = US"501 Authentication cancelled";
2155 s = ss = US"553 Initial data not expected";
2159 s = US"535 Incorrect authentication data";
2160 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2164 s = US"435 Internal error";
2165 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2166 "check", set_id, c);
2170 smtp_printf("%s\r\n", s);
2172 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2173 au->name, host_and_ident(FALSE), ss);
2175 break; /* AUTH_CMD */
2177 /* The HELO/EHLO commands are permitted to appear in the middle of a
2178 session as well as at the beginning. They have the effect of a reset in
2179 addition to their other functions. Their absence at the start cannot be
2180 taken to be an error.
2184 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2185 or 502 failure replies MUST be returned as appropriate. The SMTP
2186 server MUST stay in the same state after transmitting these replies
2187 that it was in before the EHLO was received.
2189 Therefore, we do not do the reset until after checking the command for
2190 acceptability. This change was made for Exim release 4.11. Previously
2191 it did the reset first. */
2202 HELO_EHLO: /* Common code for HELO and EHLO */
2203 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2204 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2206 /* Reject the HELO if its argument was invalid or non-existent. A
2207 successful check causes the argument to be saved in malloc store. */
2209 if (!check_helo(smtp_data))
2211 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2213 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2214 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2215 (*smtp_data == 0)? US"(no argument given)" :
2216 string_printing(smtp_data));
2218 if (++synprot_error_count > smtp_max_synprot_errors)
2220 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2221 "syntax or protocol errors (last command was \"%s\")",
2222 host_and_ident(FALSE), cmd_buffer);
2229 /* If sender_host_unknown is true, we have got here via the -bs interface,
2230 not called from inetd. Otherwise, we are running an IP connection and the
2231 host address will be set. If the helo name is the primary name of this
2232 host and we haven't done a reverse lookup, force one now. If helo_required
2233 is set, ensure that the HELO name matches the actual host. If helo_verify
2234 is set, do the same check, but softly. */
2236 if (!sender_host_unknown)
2238 BOOL old_helo_verified = helo_verified;
2239 uschar *p = smtp_data;
2241 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2244 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2245 because otherwise the log can be confusing. */
2247 if (sender_host_name == NULL &&
2248 (deliver_domain = sender_helo_name, /* set $domain */
2249 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2250 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2251 (void)host_name_lookup();
2253 /* Rebuild the fullhost info to include the HELO name (and the real name
2254 if it was looked up.) */
2256 host_build_sender_fullhost(); /* Rebuild */
2257 set_process_info("handling%s incoming connection from %s",
2258 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2260 /* Verify if configured. This doesn't give much security, but it does
2261 make some people happy to be able to do it. Note that HELO is legitimately
2262 allowed to quote an address literal. Allow for IPv6 ::ffff: literals. */
2264 helo_verified = FALSE;
2265 if (helo_required || helo_verify)
2267 BOOL tempfail = FALSE;
2269 HDEBUG(D_receive) debug_printf("verifying %s %s\n", hello,
2271 if (sender_helo_name[0] == '[')
2273 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2274 Ustrlen(sender_host_address)) == 0;
2279 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2280 helo_verified = Ustrncmp(sender_helo_name + 1,
2281 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2286 { if (helo_verified) debug_printf("matched host address\n"); }
2289 /* Do a reverse lookup if one hasn't already given a positive or
2290 negative response. If that fails, or the name doesn't match, try
2291 checking with a forward lookup. */
2295 if (sender_host_name == NULL && !host_lookup_failed)
2296 tempfail = host_name_lookup() == DEFER;
2298 /* If a host name is known, check it and all its aliases. */
2300 if (sender_host_name != NULL)
2302 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2306 HDEBUG(D_receive) debug_printf("matched host name\n");
2310 uschar **aliases = sender_host_aliases;
2311 while (*aliases != NULL)
2313 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2314 if (helo_verified) break;
2319 debug_printf("matched alias %s\n", *(--aliases));
2324 /* Final attempt: try a forward lookup of the helo name */
2330 h.name = sender_helo_name;
2334 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2336 rc = host_find_byname(&h, NULL, NULL, TRUE);
2337 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2342 if (Ustrcmp(hh->address, sender_host_address) == 0)
2344 helo_verified = TRUE;
2346 debug_printf("IP address for %s matches calling address\n",
2356 /* Verification failed. A temporary lookup failure gives a temporary
2363 smtp_printf("%d %s argument does not match calling host\r\n",
2364 tempfail? 451 : 550, hello);
2365 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2366 tempfail? "temporarily " : "",
2367 hello, sender_helo_name, host_and_ident(FALSE));
2368 helo_verified = old_helo_verified;
2369 break; /* End of HELO/EHLO processing */
2371 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2372 "helo_try_verify_hosts\n", hello);
2377 #ifdef EXPERIMENTAL_SPF
2378 /* set up SPF context */
2379 spf_init(sender_helo_name, sender_host_address);
2382 /* Apply an ACL check if one is defined */
2384 if (acl_smtp_helo != NULL)
2386 rc = acl_check(ACL_WHERE_HELO, smtp_data, acl_smtp_helo, &user_msg,
2390 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2391 sender_helo_name = NULL;
2392 host_build_sender_fullhost(); /* Rebuild */
2397 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2398 abandoning any previous message. */
2400 received_protocol = (esmtp?
2402 ((sender_host_authenticated != NULL)? pauthed : 0) +
2403 ((tls_active >= 0)? pcrpted : 0)]
2405 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2407 ((sender_host_address != NULL)? pnlocal : 0);
2409 smtp_reset(reset_point);
2412 /* Generate an OK reply, including the ident if present, and also
2413 the IP address if present. Reflecting back the ident is intended
2414 as a deterrent to mail forgers. For maximum efficiency, and also
2415 because some broken systems expect each response to be in a single
2416 packet, arrange that it is sent in one write(). */
2418 auth_advertised = FALSE;
2419 pipelining_advertised = FALSE;
2421 tls_advertised = FALSE;
2424 s = string_sprintf("250 %s Hello %s%s%s",
2425 smtp_active_hostname,
2426 (sender_ident == NULL)? US"" : sender_ident,
2427 (sender_ident == NULL)? US"" : US" at ",
2428 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2433 if (sender_host_address != NULL)
2435 s = string_cat(s, &size, &ptr, US" [", 2);
2436 s = string_cat(s, &size, &ptr, sender_host_address,
2437 Ustrlen(sender_host_address));
2438 s = string_cat(s, &size, &ptr, US"]", 1);
2441 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2443 /* If we received EHLO, we must create a multiline response which includes
2444 the functions supported. */
2450 /* I'm not entirely happy with this, as an MTA is supposed to check
2451 that it has enough room to accept a message of maximum size before
2452 it sends this. However, there seems little point in not sending it.
2453 The actual size check happens later at MAIL FROM time. By postponing it
2454 till then, VRFY and EXPN can be used after EHLO when space is short. */
2456 if (thismessage_size_limit > 0)
2458 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2459 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2463 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2466 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2467 clean; if it has an 8-bit character in its hand, it just sends it. It
2468 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2469 However, some users want this option simply in order to stop MUAs
2470 mangling messages that contain top-bit-set characters. It is therefore
2471 provided as an option. */
2473 if (accept_8bitmime)
2474 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2476 /* Advertise ETRN if there's an ACL checking whether a host is
2477 permitted to issue it; a check is made when any host actually tries. */
2479 if (acl_smtp_etrn != NULL)
2481 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2484 /* Advertise EXPN if there's an ACL checking whether a host is
2485 permitted to issue it; a check is made when any host actually tries. */
2487 if (acl_smtp_expn != NULL)
2489 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2492 /* Exim is quite happy with pipelining, so let the other end know that
2493 it is safe to use it, unless advertising is disabled. */
2495 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2497 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2498 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2499 pipelining_advertised = TRUE;
2502 /* If any server authentication mechanisms are configured, advertise
2503 them if the current host is in auth_advertise_hosts. The problem with
2504 advertising always is that some clients then require users to
2505 authenticate (and aren't configurable otherwise) even though it may not
2506 be necessary (e.g. if the host is in host_accept_relay).
2508 RFC 2222 states that SASL mechanism names contain only upper case
2509 letters, so output the names in upper case, though we actually recognize
2510 them in either case in the AUTH command. */
2514 if (verify_check_host(&auth_advertise_hosts) == OK)
2518 for (au = auths; au != NULL; au = au->next)
2520 if (au->server && (au->advertise_condition == NULL ||
2521 expand_check_condition(au->advertise_condition, au->name,
2522 US"authenticator")))
2527 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2529 auth_advertised = TRUE;
2532 s = string_cat(s, &size, &ptr, US" ", 1);
2533 s = string_cat(s, &size, &ptr, au->public_name,
2534 Ustrlen(au->public_name));
2535 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2536 au->advertised = TRUE;
2538 else au->advertised = FALSE;
2540 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2544 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2545 if it has been included in the binary, and the host matches
2546 tls_advertise_hosts. We must *not* advertise if we are already in a
2547 secure connection. */
2550 if (tls_active < 0 &&
2551 verify_check_host(&tls_advertise_hosts) != FAIL)
2553 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2554 tls_advertised = TRUE;
2558 /* Finish off the multiline reply with one that is always available. */
2560 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2563 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2569 if (tls_active >= 0) (void)tls_write(s, ptr); else
2572 fwrite(s, 1, ptr, smtp_out);
2573 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2575 break; /* HELO/EHLO */
2578 /* The MAIL command requires an address as an operand. All we do
2579 here is to parse it for syntactic correctness. The form "<>" is
2580 a special case which converts into an empty string. The start/end
2581 pointers in the original are not used further for this address, as
2582 it is the canonical extracted address which is all that is kept. */
2585 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2586 was_rej_mail = TRUE; /* Reset if accepted */
2588 if (helo_required && !helo_seen)
2590 smtp_printf("503 HELO or EHLO required\r\n");
2591 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2592 "HELO/EHLO given", host_and_ident(FALSE));
2596 if (sender_address != NULL)
2598 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2599 US"sender already given");
2603 if (smtp_data[0] == 0)
2605 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2606 US"MAIL must have an address operand");
2610 /* Check to see if the limit for messages per connection would be
2611 exceeded by accepting further messages. */
2613 if (smtp_accept_max_per_connection > 0 &&
2614 smtp_mailcmd_count > smtp_accept_max_per_connection)
2616 smtp_printf("421 too many messages in this connection\r\n");
2617 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2618 "messages in one connection", host_and_ident(TRUE));
2622 /* Reset for start of message - even if this is going to fail, we
2623 obviously need to throw away any previous data. */
2625 smtp_reset(reset_point);
2627 sender_data = recipient_data = NULL;
2629 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2633 uschar *name, *value, *end;
2634 unsigned long int size;
2636 if (!extract_option(&name, &value)) break;
2638 /* Handle SIZE= by reading the value. We don't do the check till later,
2639 in order to be able to log the sender address on failure. */
2641 if (strcmpic(name, US"SIZE") == 0 &&
2642 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2644 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2646 message_size = (int)size;
2649 /* If this session was initiated with EHLO and accept_8bitmime is set,
2650 Exim will have indicated that it supports the BODY=8BITMIME option. In
2651 fact, it does not support this according to the RFCs, in that it does not
2652 take any special action for forwarding messages containing 8-bit
2653 characters. That is why accept_8bitmime is not the default setting, but
2654 some sites want the action that is provided. We recognize both "8BITMIME"
2655 and "7BIT" as body types, but take no action. */
2657 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2658 (strcmpic(value, US"8BITMIME") == 0 ||
2659 strcmpic(value, US"7BIT") == 0)) {}
2661 /* Handle the AUTH extension. If the value given is not "<>" and either
2662 the ACL says "yes" or there is no ACL but the sending host is
2663 authenticated, we set it up as the authenticated sender. However, if the
2664 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2665 the condition is met. The value of AUTH is an xtext, which means that +,
2666 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2669 else if (strcmpic(name, US"AUTH") == 0)
2671 if (Ustrcmp(value, "<>") != 0)
2676 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2678 /* Put back terminator overrides for error message */
2681 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2682 US"invalid data for AUTH");
2686 if (acl_smtp_mailauth == NULL)
2688 ignore_msg = US"client not authenticated";
2689 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2693 ignore_msg = US"rejected by ACL";
2694 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2695 &user_msg, &log_msg);
2701 if (authenticated_by == NULL ||
2702 authenticated_by->mail_auth_condition == NULL ||
2703 expand_check_condition(authenticated_by->mail_auth_condition,
2704 authenticated_by->name, US"authenticator"))
2705 break; /* Accept the AUTH */
2707 ignore_msg = US"server_mail_auth_condition failed";
2708 if (authenticated_id != NULL)
2709 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2710 ignore_msg, authenticated_id);
2715 authenticated_sender = NULL;
2716 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2717 value, host_and_ident(TRUE), ignore_msg);
2720 /* Should only get DEFER or ERROR here. Put back terminator
2721 overrides for error message */
2726 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2733 /* Unknown option. Stick back the terminator characters and break
2734 the loop. An error for a malformed address will occur. */
2744 /* If we have passed the threshold for rate limiting, apply the current
2745 delay, and update it for next time, provided this is a limited host. */
2747 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2748 verify_check_host(&smtp_ratelimit_hosts) == OK)
2750 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2751 smtp_delay_mail/1000.0);
2752 millisleep((int)smtp_delay_mail);
2753 smtp_delay_mail *= smtp_rlm_factor;
2754 if (smtp_delay_mail > (double)smtp_rlm_limit)
2755 smtp_delay_mail = (double)smtp_rlm_limit;
2758 /* Now extract the address, first applying any SMTP-time rewriting. The
2759 TRUE flag allows "<>" as a sender address. */
2761 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2762 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2763 global_rewrite_rules) : smtp_data;
2765 /* rfc821_domains = TRUE; << no longer needed */
2767 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2769 /* rfc821_domains = FALSE; << no longer needed */
2771 if (raw_sender == NULL)
2773 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2777 sender_address = raw_sender;
2779 /* If there is a configured size limit for mail, check that this message
2780 doesn't exceed it. The check is postponed to this point so that the sender
2783 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2785 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2786 log_write(L_size_reject,
2787 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2788 "message too big: size%s=%d max=%d",
2790 host_and_ident(TRUE),
2791 (message_size == INT_MAX)? ">" : "",
2793 thismessage_size_limit);
2794 sender_address = NULL;
2798 /* Check there is enough space on the disk unless configured not to.
2799 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2800 plus the current message - i.e. we accept the message only if it won't
2801 reduce the space below the threshold. Add 5000 to the size to allow for
2802 overheads such as the Received: line and storing of recipients, etc.
2803 By putting the check here, even when SIZE is not given, it allow VRFY
2804 and EXPN etc. to be used when space is short. */
2806 if (!receive_check_fs(
2807 (smtp_check_spool_space && message_size >= 0)?
2808 message_size + 5000 : 0))
2810 smtp_printf("452 Space shortage, please try later\r\n");
2811 sender_address = NULL;
2815 /* If sender_address is unqualified, reject it, unless this is a locally
2816 generated message, or the sending host or net is permitted to send
2817 unqualified addresses - typically local machines behaving as MUAs -
2818 in which case just qualify the address. The flag is set above at the start
2819 of the SMTP connection. */
2821 if (sender_domain == 0 && sender_address[0] != 0)
2823 if (allow_unqualified_sender)
2825 sender_domain = Ustrlen(sender_address) + 1;
2826 sender_address = rewrite_address_qualify(sender_address, FALSE);
2827 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2832 smtp_printf("501 %s: sender address must contain a domain\r\n",
2834 log_write(L_smtp_syntax_error,
2835 LOG_MAIN|LOG_REJECT,
2836 "unqualified sender rejected: <%s> %s%s",
2838 host_and_ident(TRUE),
2840 sender_address = NULL;
2845 /* Apply an ACL check if one is defined, before responding */
2847 rc = (acl_smtp_mail == NULL)? OK :
2848 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2850 if (rc == OK || rc == DISCARD)
2852 smtp_printf("250 OK\r\n");
2853 smtp_delay_rcpt = smtp_rlr_base;
2854 recipients_discarded = (rc == DISCARD);
2855 was_rej_mail = FALSE;
2860 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2861 sender_address = NULL;
2866 /* The RCPT command requires an address as an operand. All we do
2867 here is to parse it for syntactic correctness. There may be any number
2868 of RCPT commands, specifying multiple senders. We build them all into
2869 a data structure that is in argc/argv format. The start/end values
2870 given by parse_extract_address are not used, as we keep only the
2871 extracted address. */
2877 /* There must be a sender address; if the sender was rejected and
2878 pipelining was advertised, we assume the client was pipelining, and do not
2879 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2880 get the same treatment. */
2882 if (sender_address == NULL)
2884 if (pipelining_advertised && last_was_rej_mail)
2886 smtp_printf("503 sender not yet given\r\n");
2887 was_rej_mail = TRUE;
2891 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2892 US"sender not yet given");
2893 was_rcpt = FALSE; /* Not a valid RCPT */
2899 /* Check for an operand */
2901 if (smtp_data[0] == 0)
2903 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2904 US"RCPT must have an address operand");
2909 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2910 as a recipient address */
2912 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2913 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2914 global_rewrite_rules) : smtp_data;
2916 /* rfc821_domains = TRUE; << no longer needed */
2917 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2918 &recipient_domain, FALSE);
2919 /* rfc821_domains = FALSE; << no longer needed */
2921 if (recipient == NULL)
2923 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2928 /* If the recipient address is unqualified, reject it, unless this is a
2929 locally generated message. However, unqualified addresses are permitted
2930 from a configured list of hosts and nets - typically when behaving as
2931 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2932 really. The flag is set at the start of the SMTP connection.
2934 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2935 assumed this meant "reserved local part", but the revision of RFC 821 and
2936 friends now makes it absolutely clear that it means *mailbox*. Consequently
2937 we must always qualify this address, regardless. */
2939 if (recipient_domain == 0)
2941 if (allow_unqualified_recipient ||
2942 strcmpic(recipient, US"postmaster") == 0)
2944 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2946 recipient_domain = Ustrlen(recipient) + 1;
2947 recipient = rewrite_address_qualify(recipient, TRUE);
2952 smtp_printf("501 %s: recipient address must contain a domain\r\n",
2954 log_write(L_smtp_syntax_error,
2955 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
2956 "<%s> %s%s", recipient, host_and_ident(TRUE),
2962 /* Check maximum allowed */
2964 if (rcpt_count > recipients_max && recipients_max > 0)
2966 if (recipients_max_reject)
2969 smtp_printf("552 too many recipients\r\n");
2971 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
2972 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
2977 smtp_printf("452 too many recipients\r\n");
2979 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
2980 "temporarily rejected: sender=<%s> %s", sender_address,
2981 host_and_ident(TRUE));
2988 /* If we have passed the threshold for rate limiting, apply the current
2989 delay, and update it for next time, provided this is a limited host. */
2991 if (rcpt_count > smtp_rlr_threshold &&
2992 verify_check_host(&smtp_ratelimit_hosts) == OK)
2994 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
2995 smtp_delay_rcpt/1000.0);
2996 millisleep((int)smtp_delay_rcpt);
2997 smtp_delay_rcpt *= smtp_rlr_factor;
2998 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
2999 smtp_delay_rcpt = (double)smtp_rlr_limit;
3002 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3003 for them. Otherwise, check the access control list for this recipient. */
3005 rc = recipients_discarded? DISCARD :
3006 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3008 /* The ACL was happy */
3012 smtp_printf("250 Accepted\r\n");
3013 receive_add_recipient(recipient, -1);
3016 /* The recipient was discarded */
3018 else if (rc == DISCARD)
3020 smtp_printf("250 Accepted\r\n");
3023 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3024 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3025 (sender_address_unrewritten != NULL)?
3026 sender_address_unrewritten : sender_address,
3027 smtp_data, recipients_discarded? "MAIL" : "RCPT",
3028 (log_msg == NULL)? US"" : US": ",
3029 (log_msg == NULL)? US"" : log_msg);
3032 /* Either the ACL failed the address, or it was deferred. */
3036 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3037 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3042 /* The DATA command is legal only if it follows successful MAIL FROM
3043 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3044 not counted as a protocol error if it follows RCPT (which must have been
3045 rejected if there are no recipients.) This function is complete when a
3046 valid DATA command is encountered.
3048 Note concerning the code used: RFC 2821 says this:
3050 - If there was no MAIL, or no RCPT, command, or all such commands
3051 were rejected, the server MAY return a "command out of sequence"
3052 (503) or "no valid recipients" (554) reply in response to the
3055 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3056 because it is the same whether pipelining is in use or not. */
3059 if (!discarded && recipients_count <= 0)
3061 if (pipelining_advertised && last_was_rcpt)
3062 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3064 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3065 US"valid RCPT command must precede DATA");
3069 if (toomany && recipients_max_reject)
3071 sender_address = NULL; /* This will allow a new MAIL without RSET */
3072 sender_address_unrewritten = NULL;
3073 smtp_printf("554 Too many recipients\r\n");
3077 if (acl_smtp_predata == NULL) rc = OK; else
3079 enable_dollar_recipients = TRUE;
3080 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3082 enable_dollar_recipients = FALSE;
3087 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3089 message_ended = END_NOTENDED; /* Indicate in middle of data */
3092 /* Either the ACL failed the address, or it was deferred. */
3095 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3101 rc = acl_check(ACL_WHERE_VRFY, smtp_data, acl_smtp_vrfy, &user_msg,
3104 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3110 /* rfc821_domains = TRUE; << no longer needed */
3111 address = parse_extract_address(smtp_data, &errmess, &start, &end,
3112 &recipient_domain, FALSE);
3113 /* rfc821_domains = FALSE; << no longer needed */
3115 if (address == NULL)
3116 s = string_sprintf("501 %s", errmess);
3119 address_item *addr = deliver_make_addr(address, FALSE);
3120 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3121 -1, -1, NULL, NULL, NULL))
3124 s = string_sprintf("250 <%s> is deliverable", address);
3128 s = (addr->message != NULL)?
3129 string_sprintf("451 <%s> %s", address, addr->message) :
3130 string_sprintf("451 Cannot resolve <%s> at this time", address);
3134 s = (addr->message != NULL)?
3135 string_sprintf("550 <%s> %s", address, addr->message) :
3136 string_sprintf("550 <%s> is not deliverable", address);
3137 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3138 smtp_data, host_and_ident(TRUE));
3143 smtp_printf("%s\r\n", s);
3149 rc = acl_check(ACL_WHERE_EXPN, smtp_data, acl_smtp_expn, &user_msg,
3152 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3155 BOOL save_log_testing_mode = log_testing_mode;
3156 address_test_mode = log_testing_mode = TRUE;
3157 (void) verify_address(deliver_make_addr(smtp_data, FALSE), smtp_out,
3158 vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1, NULL, NULL,
3160 address_test_mode = FALSE;
3161 log_testing_mode = save_log_testing_mode; /* true for -bh */
3169 if (!tls_advertised)
3171 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3172 US"STARTTLS command used when not advertised");
3176 /* Apply an ACL check if one is defined */
3178 if (acl_smtp_starttls != NULL)
3180 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3184 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3189 /* RFC 2487 is not clear on when this command may be sent, though it
3190 does state that all information previously obtained from the client
3191 must be discarded if a TLS session is started. It seems reasonble to
3192 do an implied RSET when STARTTLS is received. */
3194 incomplete_transaction_log(US"STARTTLS");
3195 smtp_reset(reset_point);
3197 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3199 /* Attempt to start up a TLS session, and if successful, discard all
3200 knowledge that was obtained previously. At least, that's what the RFC says,
3201 and that's what happens by default. However, in order to work round YAEB,
3202 there is an option to remember the esmtp state. Sigh.
3204 We must allow for an extra EHLO command and an extra AUTH command after
3205 STARTTLS that don't add to the nonmail command count. */
3207 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3209 if (!tls_remember_esmtp)
3210 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3211 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3212 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3213 if (sender_helo_name != NULL)
3215 store_free(sender_helo_name);
3216 sender_helo_name = NULL;
3217 host_build_sender_fullhost(); /* Rebuild */
3218 set_process_info("handling incoming TLS connection from %s",
3219 host_and_ident(FALSE));
3221 received_protocol = (esmtp?
3222 protocols[pextend + pcrpted +
3223 ((sender_host_authenticated != NULL)? pauthed : 0)]
3225 protocols[pnormal + pcrpted])
3227 ((sender_host_address != NULL)? pnlocal : 0);
3229 sender_host_authenticated = NULL;
3230 authenticated_id = NULL;
3231 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3232 DEBUG(D_tls) debug_printf("TLS active\n");
3233 break; /* Successful STARTTLS */
3236 /* Some local configuration problem was discovered before actually trying
3237 to do a TLS handshake; give a temporary error. */
3239 else if (rc == DEFER)
3241 smtp_printf("454 TLS currently unavailable\r\n");
3245 /* Hard failure. Reject everything except QUIT or closed connection. One
3246 cause for failure is a nested STARTTLS, in which case tls_active remains
3247 set, but we must still reject all incoming commands. */
3249 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3252 switch(smtp_read_command(FALSE))
3255 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3256 smtp_get_connection_info());
3261 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3262 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3263 smtp_get_connection_info());
3268 smtp_printf("554 Security failure\r\n");
3277 /* The ACL for QUIT is provided for gathering statistical information or
3278 similar; it does not affect the response code, but it can supply a custom
3282 incomplete_transaction_log(US"QUIT");
3284 if (acl_smtp_quit != NULL)
3286 rc = acl_check(ACL_WHERE_QUIT, US"", acl_smtp_quit,&user_msg,&log_msg);
3288 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3291 else user_msg = NULL;
3293 if (user_msg == NULL)
3294 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3296 smtp_printf("221 %s\r\n", user_msg);
3303 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3304 smtp_get_connection_info());
3309 incomplete_transaction_log(US"RSET");
3310 smtp_reset(reset_point);
3312 smtp_printf("250 Reset OK\r\n");
3313 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3318 smtp_printf("250 OK\r\n");
3322 /* Show ETRN/EXPN/VRFY if there's
3323 an ACL for checking hosts; if actually used, a check will be done for
3327 smtp_printf("214-Commands supported:\r\n");
3331 Ustrcat(buffer, " AUTH");
3333 Ustrcat(buffer, " STARTTLS");
3335 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3336 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3337 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3338 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3339 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3340 smtp_printf("214%s\r\n", buffer);
3346 incomplete_transaction_log(US"connection lost");
3347 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3349 /* Don't log by default unless in the middle of a message, as some mailers
3350 just drop the call rather than sending QUIT, and it clutters up the logs.
3353 if (sender_address != NULL || recipients_count > 0)
3354 log_write(L_lost_incoming_connection,
3356 "unexpected %s while reading SMTP command from %s%s",
3357 sender_host_unknown? "EOF" : "disconnection",
3358 host_and_ident(FALSE), smtp_read_error);
3360 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3361 smtp_get_connection_info(), smtp_read_error);
3368 if (sender_address != NULL)
3370 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3371 US"ETRN is not permitted inside a transaction");
3375 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_data,
3376 host_and_ident(FALSE));
3378 rc = acl_check(ACL_WHERE_ETRN, smtp_data, acl_smtp_etrn, &user_msg,
3382 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3386 /* Compute the serialization key for this command. */
3388 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_data);
3390 /* If a command has been specified for running as a result of ETRN, we
3391 permit any argument to ETRN. If not, only the # standard form is permitted,
3392 since that is strictly the only kind of ETRN that can be implemented
3393 according to the RFC. */
3395 if (smtp_etrn_command != NULL)
3399 etrn_command = smtp_etrn_command;
3400 deliver_domain = smtp_data;
3401 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3402 US"ETRN processing", &error);
3403 deliver_domain = NULL;
3406 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3408 smtp_printf("458 Internal failure\r\n");
3413 /* Else set up to call Exim with the -R option. */
3417 if (*smtp_data++ != '#')
3419 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3420 US"argument must begin with #");
3423 etrn_command = US"exim -R";
3424 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3428 /* If we are host-testing, don't actually do anything. */
3434 debug_printf("ETRN command is: %s\n", etrn_command);
3435 debug_printf("ETRN command execution skipped\n");
3437 smtp_printf("250 OK\r\n");
3442 /* If ETRN queue runs are to be serialized, check the database to
3443 ensure one isn't already running. */
3445 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3447 smtp_printf("458 Already processing %s\r\n", smtp_data);
3451 /* Fork a child process and run the command. We don't want to have to
3452 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3453 forking. It should be set that way anyway for external incoming SMTP,
3454 but we save and restore to be tidy. If serialization is required, we
3455 actually run the command in yet another process, so we can wait for it
3456 to complete and then remove the serialization lock. */
3458 oldsignal = signal(SIGCHLD, SIG_IGN);
3460 if ((pid = fork()) == 0)
3462 smtp_input = FALSE; /* This process is not associated with the */
3463 fclose(smtp_in); /* SMTP call any more. */
3466 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3468 /* If not serializing, do the exec right away. Otherwise, fork down
3469 into another process. */
3471 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3473 DEBUG(D_exec) debug_print_argv(argv);
3474 exim_nullstd(); /* Ensure std{in,out,err} exist */
3475 execv(CS argv[0], (char *const *)argv);
3476 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3477 etrn_command, strerror(errno));
3478 _exit(EXIT_FAILURE); /* paranoia */
3481 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3482 is, we are in the first subprocess, after forking again. All we can do
3483 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3484 complete, before removing the serialization. */
3487 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3488 "failed: %s", strerror(errno));
3492 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3494 (void)wait(&status);
3495 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3499 enq_end(etrn_serialize_key);
3500 _exit(EXIT_SUCCESS);
3503 /* Back in the top level SMTP process. Check that we started a subprocess
3504 and restore the signal state. */
3508 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3510 smtp_printf("458 Unable to fork process\r\n");
3511 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3513 else smtp_printf("250 OK\r\n");
3515 signal(SIGCHLD, oldsignal);
3520 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3521 US"unexpected argument data");
3525 /* This currently happens only for NULLs, but could be extended. */
3528 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3529 US"NULL character(s) present (shown as '?')");
3530 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3535 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3536 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3537 c = smtp_inend - smtp_inptr;
3538 if (c > 150) c = 150;
3540 incomplete_transaction_log(US"sync failure");
3541 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: "
3542 "synchronization error "
3543 "(next input sent too soon: pipelining was%s advertised): "
3544 "rejected \"%s\" %s next input=\"%s\"",
3545 pipelining_advertised? "" : " not",
3546 cmd_buffer, host_and_ident(TRUE),
3547 string_printing(smtp_inptr));
3548 smtp_printf("554 SMTP synchronization error\r\n");
3549 done = 1; /* Pretend eof - drops connection */
3553 case TOO_MANY_NONMAIL_CMD:
3554 incomplete_transaction_log(US"too many non-mail commands");
3555 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3556 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
3557 smtp_data - cmd_buffer, cmd_buffer);
3558 smtp_printf("554 Too many nonmail commands\r\n");
3559 done = 1; /* Pretend eof - drops connection */
3564 if (unknown_command_count++ >= smtp_max_unknown_commands)
3566 log_write(L_smtp_syntax_error, LOG_MAIN,
3567 "SMTP syntax error in \"%s\" %s %s",
3568 string_printing(cmd_buffer), host_and_ident(TRUE),
3569 US"unrecognized command");
3570 incomplete_transaction_log(US"unrecognized command");
3571 smtp_printf("500 Too many unrecognized commands\r\n");
3573 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3574 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3578 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3579 US"unrecognized command");
3583 /* This label is used by goto's inside loops that want to break out to
3584 the end of the command-processing loop. */
3587 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3588 last_was_rcpt = was_rcpt; /* protocol error handling */
3592 return done - 2; /* Convert yield values */
3595 /* End of smtp_in.c */