1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.1 2004/10/07 10:39:01 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2004 */
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[] = {
179 #define pauthed 1 /* added to pextend */
180 #define pcrpted 2 /* added to pextend */
181 #define pnlocal 6 /* offset to remove "local" */
183 /* When reading SMTP from a remote host, we have to use our own versions of the
184 C input-reading functions, in order to be able to flush the SMTP output only
185 when about to read more data from the socket. This is the only way to get
186 optimal performance when the client is using pipelining. Flushing for every
187 command causes a separate packet and reply packet each time; saving all the
188 responses up (when pipelining) combines them into one packet and one response.
190 For simplicity, these functions are used for *all* SMTP input, not only when
191 receiving over a socket. However, after setting up a secure socket (SSL), input
192 is read via the OpenSSL library, and another set of functions is used instead
195 These functions are set in the receive_getc etc. variables and called with the
196 same interface as the C functions. However, since there can only ever be
197 one incoming SMTP call, we just use a single buffer and flags. There is no need
198 to implement a complicated private FILE-like structure.*/
200 static uschar *smtp_inbuffer;
201 static uschar *smtp_inptr;
202 static uschar *smtp_inend;
203 static int smtp_had_eof;
204 static int smtp_had_error;
207 /*************************************************
208 * SMTP version of getc() *
209 *************************************************/
211 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
212 it flushes the output, and refills the buffer, with a timeout. The signal
213 handler is set appropriately by the calling function. This function is not used
214 after a connection has negotated itself into an TLS/SSL state.
217 Returns: the next character or EOF
223 if (smtp_inptr >= smtp_inend)
227 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
228 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
233 /* Must put the error text in fixed store, because this might be during
234 header reading, where it releases unused store above the header. */
237 smtp_had_error = save_errno;
238 smtp_read_error = string_copy_malloc(
239 string_sprintf(" (error: %s)", strerror(save_errno)));
241 else smtp_had_eof = 1;
244 smtp_inend = smtp_inbuffer + rc;
245 smtp_inptr = smtp_inbuffer;
247 return *smtp_inptr++;
252 /*************************************************
253 * SMTP version of ungetc() *
254 *************************************************/
256 /* Puts a character back in the input buffer. Only ever
262 Returns: the character
268 *(--smtp_inptr) = ch;
275 /*************************************************
276 * SMTP version of feof() *
277 *************************************************/
279 /* Tests for a previous EOF
282 Returns: non-zero if the eof flag is set
294 /*************************************************
295 * SMTP version of ferror() *
296 *************************************************/
298 /* Tests for a previous read error, and returns with errno
299 restored to what it was when the error was detected.
302 Returns: non-zero if the error flag is set
308 errno = smtp_had_error;
309 return smtp_had_error;
315 /*************************************************
316 * Write formatted string to SMTP channel *
317 *************************************************/
319 /* This is a separate function so that we don't have to repeat everything for
320 TLS support or debugging. It is global so that the daemon and the
321 authentication functions can use it. It does not return any error indication,
322 because major problems such as dropped connections won't show up till an output
323 flush for non-TLS connections. The smtp_fflush() function is available for
324 checking that: for convenience, TLS output errors are remembered here so that
325 they are also picked up later by smtp_fflush().
329 ... optional arguments
335 smtp_printf(char *format, ...)
341 va_start(ap, format);
342 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
343 debug_printf("SMTP>> %s", big_buffer);
346 va_start(ap, format);
348 /* If in a TLS session we have to format the string, and then write it using a
354 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
356 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
357 smtp_closedown(US"Unexpected error");
358 exim_exit(EXIT_FAILURE);
360 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
365 /* Otherwise, just use the standard library function. */
367 if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
373 /*************************************************
374 * Flush SMTP out and check for error *
375 *************************************************/
377 /* This function isn't currently used within Exim (it detects errors when it
378 tries to read the next SMTP input), but is available for use in local_scan().
379 For non-TLS connections, it flushes the output and checks for errors. For
380 TLS-connections, it checks for a previously-detected TLS write error.
383 Returns: 0 for no error; -1 after an error
389 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
390 return smtp_write_error;
395 /*************************************************
396 * SMTP command read timeout *
397 *************************************************/
399 /* Signal handler for timing out incoming SMTP commands. This attempts to
402 Argument: signal number (SIGALRM)
407 command_timeout_handler(int sig)
409 sig = sig; /* Keep picky compilers happy */
410 log_write(L_lost_incoming_connection,
411 LOG_MAIN, "SMTP command timeout on%s connection from %s",
412 (tls_active >= 0)? " TLS" : "",
413 host_and_ident(FALSE));
414 if (smtp_batched_input)
415 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
416 smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
417 smtp_active_hostname);
419 exim_exit(EXIT_FAILURE);
424 /*************************************************
426 *************************************************/
428 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
430 Argument: signal number (SIGTERM)
435 command_sigterm_handler(int sig)
437 sig = sig; /* Keep picky compilers happy */
438 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
439 if (smtp_batched_input)
440 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
441 smtp_printf("421 %s: Service not available - closing connection\r\n",
442 smtp_active_hostname);
443 exim_exit(EXIT_FAILURE);
448 /*************************************************
449 * Read one command line *
450 *************************************************/
452 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
453 There are sites that don't do this, and in any case internal SMTP probably
454 should check only for LF. Consequently, we check here for LF only. The line
455 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
456 an unknown command. The command is read into the static cmd_buffer.
458 The character reading routine sets up a timeout for each block actually read
459 from the input (which may contain more than one command). We set up a special
460 signal handler that closes down the session on a timeout. Control does not
464 check_sync if TRUE, check synchronization rules if global option is TRUE
466 Returns: a code identifying the command (enumerated above)
470 smtp_read_command(BOOL check_sync)
475 BOOL hadnull = FALSE;
477 os_non_restarting_signal(SIGALRM, command_timeout_handler);
479 while ((c = (receive_getc)()) != '\n' && c != EOF)
481 if (ptr >= cmd_buffer_size)
483 os_non_restarting_signal(SIGALRM, sigalrm_handler);
491 cmd_buffer[ptr++] = c;
494 receive_linecount++; /* For BSMTP errors */
495 os_non_restarting_signal(SIGALRM, sigalrm_handler);
497 /* If hit end of file, return pseudo EOF command. Whether we have a
498 part-line already read doesn't matter, since this is an error state. */
500 if (c == EOF) return EOF_CMD;
502 /* Remove any CR and white space at the end of the line, and terminate the
505 while (ptr > 0 && isspace(cmd_buffer[ptr-1])) ptr--;
508 DEBUG(D_receive) debug_printf("SMTP<< %s\n", cmd_buffer);
510 /* NULLs are not allowed in SMTP commands */
512 if (hadnull) return BADCHAR_CMD;
514 /* Scan command list and return identity, having set the data pointer
515 to the start of the actual data characters. Check for SMTP synchronization
518 for (p = cmd_list; p < cmd_list_end; p++)
520 if (strncmpic(cmd_buffer, US p->name, p->len) == 0)
522 if (smtp_inptr < smtp_inend && /* Outstanding input */
523 p->cmd < sync_cmd_limit && /* Command should sync */
524 check_sync && /* Local flag set */
525 smtp_enforce_sync && /* Global flag set */
526 sender_host_address != NULL && /* Not local input */
527 !sender_host_notsocket) /* Really is a socket */
530 /* Point after the command, but don't skip over leading spaces till after
531 the following test, so that if it fails, the command name can easily be
534 smtp_data = cmd_buffer + p->len;
536 /* Count non-mail commands from those hosts that are controlled in this
537 way. The default is all hosts. We don't waste effort checking the list
538 until we get a non-mail command, but then cache the result to save checking
539 again. If there's a DEFER while checking the host, assume it's in the list.
541 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
542 start of each incoming message by fiddling with the value in the table. */
546 if (count_nonmail == TRUE_UNSET) count_nonmail =
547 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
548 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
549 return TOO_MANY_NONMAIL_CMD;
552 /* Get the data pointer over leading spaces and return; if there is no data
553 for a command that expects it, we give the error centrally here. */
555 while (isspace(*smtp_data)) smtp_data++;
556 return (p->has_arg || *smtp_data == 0)? p->cmd : BADARG_CMD;
560 /* Enforce synchronization for unknown commands */
562 if (smtp_inptr < smtp_inend && /* Outstanding input */
563 check_sync && /* Local flag set */
564 smtp_enforce_sync && /* Global flag set */
565 sender_host_address != NULL && /* Not local input */
566 !sender_host_notsocket) /* Really is a socket */
574 /*************************************************
575 * Forced closedown of call *
576 *************************************************/
578 /* This function is called from log.c when Exim is dying because of a serious
579 disaster, and also from some other places. If an incoming non-batched SMTP
580 channel is open, it swallows the rest of the incoming message if in the DATA
581 phase, sends the reply string, and gives an error to all subsequent commands
582 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
585 Argument: SMTP reply string to send, excluding the code
590 smtp_closedown(uschar *message)
592 if (smtp_in == NULL || smtp_batched_input) return;
593 receive_swallow_smtp();
594 smtp_printf("421 %s\r\n", message);
598 switch(smtp_read_command(FALSE))
604 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
609 smtp_printf("250 Reset OK\r\n");
613 smtp_printf("421 %s\r\n", message);
622 /*************************************************
623 * Set up connection info for logging *
624 *************************************************/
626 /* This function is called when logging information about an SMTP connection.
627 It sets up appropriate source information, depending on the type of connection.
630 Returns: a string describing the connection
634 smtp_get_connection_info(void)
637 return string_sprintf("SMTP connection from %s", sender_fullhost);
639 if (sender_host_unknown || sender_host_notsocket)
640 return string_sprintf("SMTP connection from %s", sender_ident);
643 return string_sprintf("SMTP connection from %s (via inetd)", sender_fullhost);
645 if ((log_extra_selector & LX_incoming_interface) != 0 &&
646 interface_address != NULL)
647 return string_sprintf("SMTP connection from %s I=[%s]:%d", sender_fullhost,
648 interface_address, interface_port);
650 return string_sprintf("SMTP connection from %s", sender_fullhost);
655 /*************************************************
656 * Check HELO line and set sender_helo_name *
657 *************************************************/
659 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
660 the domain name of the sending host, or an ip literal in square brackets. The
661 arrgument is placed in sender_helo_name, which is in malloc store, because it
662 must persist over multiple incoming messages. If helo_accept_junk is set, this
663 host is permitted to send any old junk (needed for some broken hosts).
664 Otherwise, helo_allow_chars can be used for rogue characters in general
665 (typically people want to let in underscores).
668 s the data portion of the line (already past any white space)
670 Returns: TRUE or FALSE
674 check_helo(uschar *s)
677 uschar *end = s + Ustrlen(s);
678 BOOL yield = helo_accept_junk;
680 /* Discard any previous helo name */
682 if (sender_helo_name != NULL)
684 store_free(sender_helo_name);
685 sender_helo_name = NULL;
688 /* Skip tests if junk is permitted. */
692 /* Allow the new standard form for IPv6 address literals, namely,
693 [IPv6:....], and because someone is bound to use it, allow an equivalent
694 IPv4 form. Allow plain addresses as well. */
701 if (strncmpic(s, US"[IPv6:", 6) == 0)
702 yield = (string_is_ip_address(s+6, NULL) == 6);
703 else if (strncmpic(s, US"[IPv4:", 6) == 0)
704 yield = (string_is_ip_address(s+6, NULL) == 4);
706 yield = (string_is_ip_address(s+1, NULL) != 0);
711 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
712 that have been configured (usually underscore - sigh). */
719 if (!isalnum(*s) && *s != '.' && *s != '-' &&
720 Ustrchr(helo_allow_chars, *s) == NULL)
730 /* Save argument if OK */
732 if (yield) sender_helo_name = string_copy_malloc(start);
740 /*************************************************
741 * Extract SMTP command option *
742 *************************************************/
744 /* This function picks the next option setting off the end of smtp_data. It
745 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
746 things that can appear there.
749 name point this at the name
750 value point this at the data string
752 Returns: TRUE if found an option
756 extract_option(uschar **name, uschar **value)
759 uschar *v = smtp_data + Ustrlen(smtp_data) -1;
760 while (isspace(*v)) v--;
763 while (v > smtp_data && *v != '=' && !isspace(*v)) v--;
764 if (*v != '=') return FALSE;
767 while(isalpha(n[-1])) n--;
769 if (n[-1] != ' ') return FALSE;
784 /*************************************************
785 * Reset for new message *
786 *************************************************/
788 /* This function is called whenever the SMTP session is reset from
789 within either of the setup functions.
791 Argument: the stacking pool storage reset point
796 smtp_reset(void *reset_point)
799 store_reset(reset_point);
800 recipients_list = NULL;
801 rcpt_count = rcpt_defer_count = rcpt_fail_count =
802 raw_recipients_count = recipients_count = recipients_list_max = 0;
804 acl_warn_headers = NULL;
805 queue_only_policy = FALSE;
806 deliver_freeze = FALSE; /* Can be set by ACL */
807 submission_mode = FALSE; /* Can be set by ACL */
808 sender_address = NULL;
809 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
810 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
811 sender_verified_list = NULL; /* No senders verified */
812 memset(sender_address_cache, 0, sizeof(sender_address_cache));
813 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
814 authenticated_sender = NULL;
815 body_linecount = body_zerocount = 0;
817 for (i = 0; i < ACL_M_MAX; i++) acl_var[ACL_C_MAX + i] = NULL;
819 /* The message body variables use malloc store. They may be set if this is
820 not the first message in an SMTP session and the previous message caused them
821 to be referenced in an ACL. */
823 if (message_body != NULL)
825 store_free(message_body);
829 if (message_body_end != NULL)
831 store_free(message_body_end);
832 message_body_end = NULL;
835 /* Warning log messages are also saved in malloc store. They are saved to avoid
836 repetition in the same message, but it seems right to repeat them for different
839 while (acl_warn_logged != NULL)
841 string_item *this = acl_warn_logged;
842 acl_warn_logged = acl_warn_logged->next;
851 /*************************************************
852 * Initialize for incoming batched SMTP message *
853 *************************************************/
855 /* This function is called from smtp_setup_msg() in the case when
856 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
857 of messages in one file with SMTP commands between them. All errors must be
858 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
859 relevant. After an error on a sender, or an invalid recipient, the remainder
860 of the message is skipped. The value of received_protocol is already set.
863 Returns: > 0 message successfully started (reached DATA)
864 = 0 QUIT read or end of file reached
869 smtp_setup_batch_msg(void)
872 void *reset_point = store_get(0);
874 /* Save the line count at the start of each transaction - single commands
875 like HELO and RSET count as whole transactions. */
877 bsmtp_transaction_linecount = receive_linecount;
879 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
881 smtp_reset(reset_point); /* Reset for start of message */
883 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
884 value. The values are 2 larger than the required yield of the function. */
889 uschar *recipient = NULL;
890 int start, end, sender_domain, recipient_domain;
892 switch(smtp_read_command(FALSE))
894 /* The HELO/EHLO commands set sender_address_helo if they have
895 valid data; otherwise they are ignored, except that they do
896 a reset of the state. */
901 check_helo(smtp_data);
905 smtp_reset(reset_point);
906 bsmtp_transaction_linecount = receive_linecount;
910 /* The MAIL FROM command requires an address as an operand. All we
911 do here is to parse it for syntactic correctness. The form "<>" is
912 a special case which converts into an empty string. The start/end
913 pointers in the original are not used further for this address, as
914 it is the canonical extracted address which is all that is kept. */
917 if (sender_address != NULL)
918 /* The function moan_smtp_batch() does not return. */
919 moan_smtp_batch(cmd_buffer, "503 Sender already given");
921 if (smtp_data[0] == 0)
922 /* The function moan_smtp_batch() does not return. */
923 moan_smtp_batch(cmd_buffer, "501 MAIL FROM must have an address operand");
925 /* Reset to start of message */
927 smtp_reset(reset_point);
929 /* Apply SMTP rewrite */
931 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
932 rewrite_one(smtp_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
933 US"", global_rewrite_rules) : smtp_data;
935 /* Extract the address; the TRUE flag allows <> as valid */
938 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
941 if (raw_sender == NULL)
942 /* The function moan_smtp_batch() does not return. */
943 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
945 sender_address = string_copy(raw_sender);
947 /* Qualify unqualified sender addresses if permitted to do so. */
949 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
951 if (allow_unqualified_sender)
953 sender_address = rewrite_address_qualify(sender_address, FALSE);
954 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
955 "and rewritten\n", raw_sender);
957 /* The function moan_smtp_batch() does not return. */
958 else moan_smtp_batch(cmd_buffer, "501 sender address must contain "
964 /* The RCPT TO command requires an address as an operand. All we do
965 here is to parse it for syntactic correctness. There may be any number
966 of RCPT TO commands, specifying multiple senders. We build them all into
967 a data structure that is in argc/argv format. The start/end values
968 given by parse_extract_address are not used, as we keep only the
969 extracted address. */
972 if (sender_address == NULL)
973 /* The function moan_smtp_batch() does not return. */
974 moan_smtp_batch(cmd_buffer, "503 No sender yet given");
976 if (smtp_data[0] == 0)
977 /* The function moan_smtp_batch() does not return. */
978 moan_smtp_batch(cmd_buffer, "501 RCPT TO must have an address operand");
980 /* Check maximum number allowed */
982 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
983 /* The function moan_smtp_batch() does not return. */
984 moan_smtp_batch(cmd_buffer, "%s too many recipients",
985 recipients_max_reject? "552": "452");
987 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
990 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
991 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
992 global_rewrite_rules) : smtp_data;
994 /* rfc821_domains = TRUE; << no longer needed */
995 recipient = parse_extract_address(recipient, &errmess, &start, &end,
996 &recipient_domain, FALSE);
997 /* rfc821_domains = FALSE; << no longer needed */
999 if (recipient == NULL)
1000 /* The function moan_smtp_batch() does not return. */
1001 moan_smtp_batch(cmd_buffer, "501 %s", errmess);
1003 /* If the recipient address is unqualified, qualify it if permitted. Then
1004 add it to the list of recipients. */
1006 if (recipient_domain == 0)
1008 if (allow_unqualified_recipient)
1010 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1012 recipient = rewrite_address_qualify(recipient, TRUE);
1014 /* The function moan_smtp_batch() does not return. */
1015 else moan_smtp_batch(cmd_buffer, "501 recipient address must contain "
1018 receive_add_recipient(recipient, -1);
1022 /* The DATA command is legal only if it follows successful MAIL FROM
1023 and RCPT TO commands. This function is complete when a valid DATA
1024 command is encountered. */
1027 if (sender_address == NULL || recipients_count <= 0)
1029 /* The function moan_smtp_batch() does not return. */
1030 if (sender_address == NULL)
1031 moan_smtp_batch(cmd_buffer,
1032 "503 MAIL FROM:<sender> command must precede DATA");
1034 moan_smtp_batch(cmd_buffer,
1035 "503 RCPT TO:<recipient> must precede DATA");
1039 done = 3; /* DATA successfully achieved */
1040 message_ended = END_NOTENDED; /* Indicate in middle of message */
1045 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1052 bsmtp_transaction_linecount = receive_linecount;
1063 /* The function moan_smtp_batch() does not return. */
1064 moan_smtp_batch(cmd_buffer, "501 Unexpected argument data");
1069 /* The function moan_smtp_batch() does not return. */
1070 moan_smtp_batch(cmd_buffer, "501 Unexpected NULL in SMTP command");
1075 /* The function moan_smtp_batch() does not return. */
1076 moan_smtp_batch(cmd_buffer, "500 Command unrecognized");
1081 return done - 2; /* Convert yield values */
1087 /*************************************************
1088 * Start an SMTP session *
1089 *************************************************/
1091 /* This function is called at the start of an SMTP session. Thereafter,
1092 smtp_setup_msg() is called to initiate each separate message. This
1093 function does host-specific testing, and outputs the banner line.
1096 Returns: FALSE if the session can not continue; something has
1097 gone wrong, or the connection to the host is blocked
1101 smtp_start_session(void)
1107 helo_seen = esmtp = helo_accept_junk = FALSE;
1108 count_nonmail = TRUE_UNSET;
1109 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1110 smtp_delay_mail = smtp_rlm_base;
1111 auth_advertised = FALSE;
1112 pipelining_advertised = FALSE;
1113 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1115 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1117 sender_host_authenticated = NULL;
1118 authenticated_by = NULL;
1121 tls_cipher = tls_peerdn = NULL;
1122 tls_advertised = FALSE;
1125 /* Reset ACL connection variables */
1127 for (i = 0; i < ACL_C_MAX; i++) acl_var[i] = NULL;
1129 cmd_buffer = (uschar *)malloc(cmd_buffer_size + 1); /* allow for trailing 0 */
1130 if (cmd_buffer == NULL)
1131 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1132 "malloc() failed for SMTP command buffer");
1134 /* For batched input, the protocol setting can be overridden from the
1135 command line by a trusted caller. */
1137 if (smtp_batched_input)
1139 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1142 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1143 reset later if any of EHLO/AUTH/STARTTLS are received. */
1147 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1149 /* Set up the buffer for inputting using direct read() calls, and arrange to
1150 call the local functions instead of the standard C ones. */
1152 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1153 if (smtp_inbuffer == NULL)
1154 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1155 receive_getc = smtp_getc;
1156 receive_ungetc = smtp_ungetc;
1157 receive_feof = smtp_feof;
1158 receive_ferror = smtp_ferror;
1159 smtp_inptr = smtp_inend = smtp_inbuffer;
1160 smtp_had_eof = smtp_had_error = 0;
1162 /* Set up the message size limit; this may be host-specific */
1164 thismessage_size_limit = expand_string_integer(message_size_limit);
1165 if (thismessage_size_limit < 0)
1167 if (thismessage_size_limit == -1)
1168 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1169 "%s", expand_string_message);
1171 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1172 "%s", expand_string_message);
1173 smtp_closedown(US"Temporary local problem - please try later");
1177 /* When a message is input locally via the -bs or -bS options, sender_host_
1178 unknown is set unless -oMa was used to force an IP address, in which case it
1179 is checked like a real remote connection. When -bs is used from inetd, this
1180 flag is not set, causing the sending host to be checked. The code that deals
1181 with IP source routing (if configured) is never required for -bs or -bS and
1182 the flag sender_host_notsocket is used to suppress it.
1184 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1185 reserve for certain hosts and/or networks. */
1187 if (!sender_host_unknown)
1190 BOOL reserved_host = FALSE;
1192 /* Look up IP options (source routing info) on the socket if this is not an
1193 -oMa "host", and if any are found, log them and drop the connection.
1195 Linux (and others now, see below) is different to everyone else, so there
1196 has to be some conditional compilation here. Versions of Linux before 2.1.15
1197 used a structure whose name was "options". Somebody finally realized that
1198 this name was silly, and it got changed to "ip_options". I use the
1199 newer name here, but there is a fudge in the script that sets up os.h
1200 to define a macro in older Linux systems.
1202 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1203 glibc 2, which has chosen ip_opts for the structure name. This is now
1204 really a glibc thing rather than a Linux thing, so the condition name
1205 has been changed to reflect this. It is relevant also to GNU/Hurd.
1207 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1208 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1209 a special macro defined in the os.h file.
1211 Some DGUX versions on older hardware appear not to support IP options at
1212 all, so there is now a general macro which can be set to cut out this
1215 How to do this properly in IPv6 is not yet known. */
1217 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1219 #ifdef GLIBC_IP_OPTIONS
1220 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1225 #elif defined DARWIN_IP_OPTIONS
1231 if (!host_checking && !sender_host_notsocket)
1234 SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1235 struct ip_options *ipopt = store_get(optlen);
1237 struct ip_opts ipoptblock;
1238 struct ip_opts *ipopt = &ipoptblock;
1239 SOCKLEN_T optlen = sizeof(ipoptblock);
1241 struct ipoption ipoptblock;
1242 struct ipoption *ipopt = &ipoptblock;
1243 SOCKLEN_T optlen = sizeof(ipoptblock);
1246 /* Occasional genuine failures of getsockopt() have been seen - for
1247 example, "reset by peer". Therefore, just log and give up on this
1248 call, unless the error is ENOPROTOOPT. This error is given by systems
1249 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1250 of writing. So for that error, carry on - we just can't do an IP options
1253 DEBUG(D_receive) debug_printf("checking for IP options\n");
1255 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1258 if (errno != ENOPROTOOPT)
1260 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1261 host_and_ident(FALSE), strerror(errno));
1262 smtp_printf("451 SMTP service not available\r\n");
1267 /* Deal with any IP options that are set. On the systems I have looked at,
1268 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1269 more logging data than will fit in big_buffer. Nevertheless, after somebody
1270 questioned this code, I've added in some paranoid checking. */
1272 else if (optlen > 0)
1274 uschar *p = big_buffer;
1275 uschar *pend = big_buffer + big_buffer_size;
1276 uschar *opt, *adptr;
1278 struct in_addr addr;
1281 uschar *optstart = (uschar *)(ipopt->__data);
1283 uschar *optstart = (uschar *)(ipopt->ip_opts);
1285 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1288 DEBUG(D_receive) debug_printf("IP options exist\n");
1290 Ustrcpy(p, "IP options on incoming call:");
1293 for (opt = optstart; opt != NULL &&
1294 opt < (uschar *)(ipopt) + optlen;)
1308 if (!string_format(p, pend-p, " %s [@%s",
1309 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1311 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1313 inet_ntoa(ipopt->ip_dst)))
1315 inet_ntoa(ipopt->ipopt_dst)))
1323 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1325 while (optcount-- > 0)
1327 memcpy(&addr, adptr, sizeof(addr));
1328 if (!string_format(p, pend - p - 1, "%s%s",
1329 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1335 adptr += sizeof(struct in_addr);
1344 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1347 for (i = 0; i < opt[1]; i++)
1349 sprintf(CS p, "%2.2x ", opt[i]);
1360 log_write(0, LOG_MAIN, "%s", big_buffer);
1362 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1364 log_write(0, LOG_MAIN|LOG_REJECT,
1365 "connection from %s refused (IP options)", host_and_ident(FALSE));
1367 smtp_printf("554 SMTP service not available\r\n");
1371 /* Length of options = 0 => there are no options */
1373 else DEBUG(D_receive) debug_printf("no IP options found\n");
1375 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1377 /* Set keep-alive in socket options. The option is on by default. This
1378 setting is an attempt to get rid of some hanging connections that stick in
1379 read() when the remote end (usually a dialup) goes away. */
1381 if (smtp_accept_keepalive && !sender_host_notsocket)
1382 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1384 /* If the current host matches host_lookup, set the name by doing a
1385 reverse lookup. On failure, sender_host_name will be NULL and
1386 host_lookup_failed will be TRUE. This may or may not be serious - optional
1389 if (verify_check_host(&host_lookup) == OK)
1391 (void)host_name_lookup();
1392 host_build_sender_fullhost();
1395 /* Delay this until we have the full name, if it is looked up. */
1397 set_process_info("handling incoming connection from %s",
1398 host_and_ident(FALSE));
1400 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1401 smtps port for use with older style SSL MTAs. */
1404 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1408 /* Test for explicit connection rejection */
1410 if (verify_check_host(&host_reject_connection) == OK)
1412 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1413 "from %s (host_reject_connection)", host_and_ident(FALSE));
1414 smtp_printf("554 SMTP service not available\r\n");
1418 /* Test with TCP Wrappers if so configured */
1420 #ifdef USE_TCP_WRAPPERS
1421 if (!hosts_ctl("exim",
1422 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1423 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1424 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1426 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1427 log_write(L_connection_reject,
1428 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1429 "(tcp wrappers)", host_and_ident(FALSE));
1430 smtp_printf("554 SMTP service not available\r\n");
1435 /* Check for reserved slots. Note that the count value doesn't include
1436 this process, as it gets upped in the parent process. */
1438 if (smtp_accept_max > 0 &&
1439 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1441 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1443 log_write(L_connection_reject,
1444 LOG_MAIN, "temporarily refused connection from %s: not in "
1445 "reserve list: connected=%d max=%d reserve=%d%s",
1446 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1447 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1448 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1449 "please try again later\r\n", smtp_active_hostname);
1452 reserved_host = TRUE;
1455 /* If a load level above which only messages from reserved hosts are
1456 accepted is set, check the load. For incoming calls via the daemon, the
1457 check is done in the superior process if there are no reserved hosts, to
1458 save a fork. In all cases, the load average will already be available
1459 in a global variable at this point. */
1461 if (smtp_load_reserve >= 0 &&
1462 load_average > smtp_load_reserve &&
1464 verify_check_host(&smtp_reserve_hosts) != OK)
1466 log_write(L_connection_reject,
1467 LOG_MAIN, "temporarily refused connection from %s: not in "
1468 "reserve list and load average = %.2f", host_and_ident(FALSE),
1469 (double)load_average/1000.0);
1470 smtp_printf("421 %s: Too much load; please try again later\r\n",
1471 smtp_active_hostname);
1475 /* Determine whether unqualified senders or recipients are permitted
1476 for this host. Unfortunately, we have to do this every time, in order to
1477 set the flags so that they can be inspected when considering qualifying
1478 addresses in the headers. For a site that permits no qualification, this
1479 won't take long, however. */
1481 allow_unqualified_sender =
1482 verify_check_host(&sender_unqualified_hosts) == OK;
1484 allow_unqualified_recipient =
1485 verify_check_host(&recipient_unqualified_hosts) == OK;
1487 /* Determine whether HELO/EHLO is required for this host. The requirement
1488 can be hard or soft. */
1490 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1492 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1494 /* Determine whether this hosts is permitted to send syntactic junk
1495 after a HELO or EHLO command. */
1497 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1500 /* For batch SMTP input we are now done. */
1502 if (smtp_batched_input) return TRUE;
1504 /* Run the ACL if it exists */
1506 if (acl_smtp_connect != NULL)
1509 uschar *user_msg, *log_msg;
1510 smtp_data = US"in \"connect\" ACL"; /* For logged failure message */
1511 rc = acl_check(ACL_WHERE_CONNECT, US"", acl_smtp_connect, &user_msg,
1515 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1520 /* Output the initial message for a two-way SMTP connection. It may contain
1521 newlines, which then cause a multi-line response to be given. */
1523 s = expand_string(smtp_banner);
1525 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1526 "failed: %s", smtp_banner, expand_string_message);
1528 /* Remove any terminating newlines; might as well remove trailing space too */
1531 while (p > s && isspace(p[-1])) p--;
1534 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1535 is all contained in a single IP packet. The original code wrote out the
1536 greeting using several calls to fprint/fputc, and on busy servers this could
1537 cause it to be split over more than one packet - which caused CC:Mail to fall
1538 over when it got the second part of the greeting after sending its first
1539 command. Sigh. To try to avoid this, build the complete greeting message
1540 first, and output it in one fell swoop. This gives a better chance of it
1541 ending up as a single packet. */
1543 ss = store_get(size);
1547 do /* At least once, in case we have an empty string */
1550 uschar *linebreak = Ustrchr(p, '\n');
1551 if (linebreak == NULL)
1554 ss = string_cat(ss, &size, &ptr, US"220 ", 4);
1558 len = linebreak - p;
1559 ss = string_cat(ss, &size, &ptr, US"220-", 4);
1561 ss = string_cat(ss, &size, &ptr, p, len);
1562 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1564 if (linebreak != NULL) p++;
1568 ss[ptr] = 0; /* string_cat leaves room for this */
1570 /* Before we write the banner, check that there is no input pending, unless
1571 this synchronisation check is disabled. */
1573 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1576 struct timeval tzero;
1580 FD_SET(fileno(smtp_in), &fds);
1581 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1584 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: "
1585 "synchronization error (input sent without waiting for greeting): "
1586 "rejected connection from %s", host_and_ident(TRUE));
1587 smtp_printf("554 SMTP synchronization error\r\n");
1592 /* Now output the banner */
1594 smtp_printf("%s", ss);
1602 /*************************************************
1603 * Handle SMTP syntax and protocol errors *
1604 *************************************************/
1606 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1607 to do so. Then transmit the error response. The return value depends on the
1608 number of syntax and protocol errors in this SMTP session.
1611 type error type, given as a log flag bit
1612 code response code; <= 0 means don't send a response
1613 data data to reflect in the response (can be NULL)
1614 errmess the error message
1616 Returns: -1 limit of syntax/protocol errors NOT exceeded
1617 +1 limit of syntax/protocol errors IS exceeded
1619 These values fit in with the values of the "done" variable in the main
1620 processing loop in smtp_setup_msg(). */
1623 synprot_error(int type, int code, uschar *data, uschar *errmess)
1627 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1628 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1629 string_printing(cmd_buffer), host_and_ident(TRUE), errmess);
1631 if (++synprot_error_count > smtp_max_synprot_errors)
1634 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1635 "syntax or protocol errors (last command was \"%s\")",
1636 host_and_ident(FALSE), cmd_buffer);
1641 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1642 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1644 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1653 /*************************************************
1654 * Log incomplete transactions *
1655 *************************************************/
1657 /* This function is called after a transaction has been aborted by RSET, QUIT,
1658 connection drops or other errors. It logs the envelope information received
1659 so far in order to preserve address verification attempts.
1661 Argument: string to indicate what aborted the transaction
1666 incomplete_transaction_log(uschar *what)
1668 if (sender_address == NULL || /* No transaction in progress */
1669 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1672 /* Build list of recipients for logging */
1674 if (recipients_count > 0)
1677 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1678 for (i = 0; i < recipients_count; i++)
1679 raw_recipients[i] = recipients_list[i].address;
1680 raw_recipients_count = recipients_count;
1683 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1684 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1690 /*************************************************
1691 * Send SMTP response, possibly multiline *
1692 *************************************************/
1694 /* There are, it seems, broken clients out there that cannot handle multiline
1695 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1696 output nothing for non-final calls, and only the first line for anything else.
1700 final FALSE if the last line isn't the final line
1701 msg message text, possibly containing newlines
1707 smtp_respond(int code, BOOL final, uschar *msg)
1709 if (!final && no_multiline_responses) return;
1713 uschar *nl = Ustrchr(msg, '\n');
1716 smtp_printf("%d%c%s\r\n", code, final? ' ':'-', msg);
1719 else if (nl[1] == 0 || no_multiline_responses)
1721 smtp_printf("%d%c%.*s\r\n", code, final? ' ':'-', (int)(nl - msg), msg);
1726 smtp_printf("%d-%.*s\r\n", code, (int)(nl - msg), msg);
1728 while (isspace(*msg)) msg++;
1736 /*************************************************
1737 * Handle an ACL failure *
1738 *************************************************/
1740 /* This function is called when acl_check() fails. As well as calls from within
1741 this module, it is called from receive.c for an ACL after DATA. It sorts out
1742 logging the incident, and sets up the error response. A message containing
1743 newlines is turned into a multiline SMTP response, but for logging, only the
1746 There's a table of the response codes to use in globals.c, along with the table
1747 of names. VFRY is special. Despite RFC1123 it defaults disabled in Exim.
1748 However, discussion in connection with RFC 821bis (aka RFC 2821) has concluded
1749 that the response should be 252 in the disabled state, because there are broken
1750 clients that try VRFY before RCPT. A 5xx response should be given only when the
1751 address is positively known to be undeliverable. Sigh. Also, for ETRN, 458 is
1752 given on refusal, and for AUTH, 503.
1755 where where the ACL was called from
1757 user_msg a message that can be included in an SMTP response
1758 log_msg a message for logging
1760 Returns: 0 in most cases
1761 2 if the failure code was FAIL_DROP, in which case the
1762 SMTP connection should be dropped (this value fits with the
1763 "done" variable in smtp_setup_msg() below)
1767 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1769 int code = acl_wherecodes[where];
1770 BOOL drop = rc == FAIL_DROP;
1772 uschar *sender_info = US"";
1773 uschar *what = (where == ACL_WHERE_PREDATA)? US"DATA" :
1774 (where == ACL_WHERE_DATA)? US"after DATA" :
1775 string_sprintf("%s %s", acl_wherenames[where], smtp_data);
1777 if (drop) rc = FAIL;
1779 /* We used to have sender_address here; however, there was a bug that was not
1780 updating sender_address after a rewrite during a verify. When this bug was
1781 fixed, sender_address at this point became the rewritten address. I'm not sure
1782 this is what should be logged, so I've changed to logging the unrewritten
1783 address to retain backward compatibility. */
1785 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1787 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1788 sender_address_unrewritten : sender_address);
1791 /* If there's been a sender verification failure with a specific message, and
1792 we have not sent a response about it yet, do so now, as a preliminary line for
1793 failures, but not defers. However, log it in both cases. */
1795 if (sender_verified_failed != NULL &&
1796 !testflag(sender_verified_failed, af_sverify_told))
1798 setflag(sender_verified_failed, af_sverify_told);
1800 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1801 host_and_ident(TRUE),
1802 ((sender_verified_failed->special_action & 255) == DEFER)? "defer" : "fail",
1803 sender_verified_failed->address,
1804 (sender_verified_failed->message == NULL)? US"" :
1805 string_sprintf(": %s", sender_verified_failed->message));
1807 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1808 smtp_respond(code, FALSE, string_sprintf(
1809 testflag(sender_verified_failed, af_verify_pmfail)?
1810 "Postmaster verification failed while checking <%s>\n%s\n"
1811 "Several RFCs state that you are required to have a postmaster\n"
1812 "mailbox for each mail domain. This host does not accept mail\n"
1813 "from domains whose servers reject the postmaster address."
1815 testflag(sender_verified_failed, af_verify_nsfail)?
1816 "Callback setup failed while verifying <%s>\n%s\n"
1817 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
1818 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
1819 "RFC requirements, and stops you from receiving standard bounce\n"
1820 "messages. This host does not accept mail from domains whose servers\n"
1823 "Verification failed for <%s>\n%s",
1824 sender_verified_failed->address,
1825 sender_verified_failed->user_message));
1828 /* Sort out text for logging */
1830 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
1831 lognl = Ustrchr(log_msg, '\n');
1832 if (lognl != NULL) *lognl = 0;
1834 /* Send permanent failure response to the command, but the code used isn't
1835 always a 5xx one - see comments at the start of this function. If the original
1836 rc was FAIL_DROP we drop the connection and yield 2. */
1838 if (rc == FAIL) smtp_respond(code, TRUE, (user_msg == NULL)?
1839 US"Administrative prohibition" : user_msg);
1841 /* Send temporary failure response to the command. Don't give any details,
1842 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
1843 verb, and for a header verify when smtp_return_error_details is set.
1845 This conditional logic is all somewhat of a mess because of the odd
1846 interactions between temp_details and return_error_details. One day it should
1847 be re-implemented in a tidier fashion. */
1851 if (acl_temp_details && user_msg != NULL)
1853 if (smtp_return_error_details &&
1854 sender_verified_failed != NULL &&
1855 sender_verified_failed->message != NULL)
1857 smtp_respond(451, FALSE, sender_verified_failed->message);
1859 smtp_respond(451, TRUE, user_msg);
1862 smtp_printf("451 Temporary local problem - please try later\r\n");
1865 /* Log the incident. If the connection is not forcibly to be dropped, return 0.
1866 Otherwise, log why it is closing if required and return 2. */
1868 log_write(0, LOG_MAIN|LOG_REJECT, "%s %s%srejected %s%s",
1869 host_and_ident(TRUE),
1870 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
1872 if (!drop) return 0;
1874 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
1875 smtp_get_connection_info());
1882 /*************************************************
1883 * Initialize for SMTP incoming message *
1884 *************************************************/
1886 /* This function conducts the initial dialogue at the start of an incoming SMTP
1887 message, and builds a list of recipients. However, if the incoming message
1888 is part of a batch (-bS option) a separate function is called since it would
1889 be messy having tests splattered about all over this function. This function
1890 therefore handles the case where interaction is occurring. The input and output
1891 files are set up in smtp_in and smtp_out.
1893 The global recipients_list is set to point to a vector of recipient_item
1894 blocks, whose number is given by recipients_count. This is extended by the
1895 receive_add_recipient() function. The global variable sender_address is set to
1896 the sender's address. The yield is +1 if a message has been successfully
1897 started, 0 if a QUIT command was encountered or the connection was refused from
1898 the particular host, or -1 if the connection was lost.
1902 Returns: > 0 message successfully started (reached DATA)
1903 = 0 QUIT read or end of file reached or call refused
1908 smtp_setup_msg(void)
1911 BOOL toomany = FALSE;
1912 BOOL discarded = FALSE;
1913 BOOL last_was_rej_mail = FALSE;
1914 BOOL last_was_rcpt = FALSE;
1915 void *reset_point = store_get(0);
1917 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
1919 /* Reset for start of new message. We allow one RSET not to be counted as a
1920 nonmail command, for those MTAs that insist on sending it between every
1921 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
1922 TLS between messages (an Exim client may do this if it has messages queued up
1923 for the host). Note: we do NOT reset AUTH at this point. */
1925 smtp_reset(reset_point);
1926 message_ended = END_NOTSTARTED;
1928 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
1929 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
1930 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
1932 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
1935 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
1937 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
1939 /* Batched SMTP is handled in a different function. */
1941 if (smtp_batched_input) return smtp_setup_batch_msg();
1943 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1944 value. The values are 2 larger than the required yield of the function. */
1949 uschar *etrn_command;
1950 uschar *etrn_serialize_key;
1952 uschar *user_msg, *log_msg;
1953 uschar *recipient = NULL;
1954 uschar *hello = NULL;
1955 uschar *set_id = NULL;
1957 BOOL was_rej_mail = FALSE;
1958 BOOL was_rcpt = FALSE;
1959 void (*oldsignal)(int);
1961 int start, end, sender_domain, recipient_domain;
1966 switch(smtp_read_command(TRUE))
1968 /* The AUTH command is not permitted to occur inside a transaction, and may
1969 occur successfully only once per connection, and then only when we've
1970 advertised it. Actually, that isn't quite true. When TLS is started, all
1971 previous information about a connection must be discarded, so a new AUTH is
1972 permitted at that time.
1974 AUTH is initially labelled as a "nonmail command" so that one occurrence
1975 doesn't get counted. We change the label here so that multiple failing
1976 AUTHS will eventually hit the nonmail threshold. */
1979 authentication_failed = TRUE;
1980 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
1982 if (!auth_advertised)
1984 done = synprot_error(L_smtp_protocol_error, 503, NULL,
1985 US"AUTH command used when not advertised");
1988 if (sender_host_authenticated != NULL)
1990 done = synprot_error(L_smtp_protocol_error, 503, NULL,
1991 US"already authenticated");
1994 if (sender_address != NULL)
1996 done = synprot_error(L_smtp_protocol_error, 503, NULL,
1997 US"not permitted in mail transaction");
2003 if (acl_smtp_auth != NULL)
2005 rc = acl_check(ACL_WHERE_AUTH, smtp_data, acl_smtp_auth, &user_msg,
2009 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2014 /* Find the name of the requested authentication mechanism. */
2017 while ((c = *smtp_data) != 0 && !isspace(c))
2019 if (!isalnum(c) && c != '-' && c != '_')
2021 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2022 US"invalid character in authentication mechanism name");
2028 /* If not at the end of the line, we must be at white space. Terminate the
2029 name and move the pointer on to any data that may be present. */
2031 if (*smtp_data != 0)
2034 while (isspace(*smtp_data)) smtp_data++;
2037 /* Search for an authentication mechanism which is configured for use
2038 as a server and which has been advertised. */
2040 for (au = auths; au != NULL; au = au->next)
2042 if (strcmpic(s, au->public_name) == 0 && au->server &&
2043 au->advertised) break;
2048 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2049 string_sprintf("%s authentication mechanism not supported", s));
2053 /* Run the checking code, passing the remainder of the command
2054 line as data. Initialize $0 empty. The authenticator may set up
2055 other numeric variables. Afterwards, have a go at expanding the set_id
2056 string, even if authentication failed - for bad passwords it can be useful
2057 to log the userid. On success, require set_id to expand and exist, and
2058 put it in authenticated_id. Save this in permanent store, as the working
2059 store gets reset at HELO, RSET, etc. */
2062 expand_nlength[0] = 0; /* $0 contains nothing */
2064 c = (au->info->servercode)(au, smtp_data);
2065 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2066 expand_nmax = -1; /* Reset numeric variables */
2068 /* For the non-OK cases, set up additional logging data if set_id
2073 if (set_id != NULL && *set_id != 0)
2074 set_id = string_sprintf(" (set_id=%s)", set_id);
2078 /* Switch on the result */
2083 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2085 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2086 sender_host_authenticated = au->name;
2087 authentication_failed = FALSE;
2089 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2090 ((sender_host_address != NULL)? pnlocal : 0);
2091 s = ss = US"235 Authentication succeeded";
2092 authenticated_by = au;
2096 /* Authentication succeeded, but we failed to expand the set_id string.
2097 Treat this as a temporary error. */
2099 auth_defer_msg = expand_string_message;
2103 s = string_sprintf("435 Unable to authenticate at present%s",
2104 auth_defer_user_msg);
2105 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2106 set_id, auth_defer_msg);
2110 s = ss = US"501 Invalid base64 data";
2114 s = ss = US"501 Authentication cancelled";
2118 s = ss = US"553 Initial data not expected";
2122 s = US"535 Incorrect authentication data";
2123 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2127 s = US"435 Internal error";
2128 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2129 "check", set_id, c);
2133 smtp_printf("%s\r\n", s);
2135 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2136 au->name, host_and_ident(FALSE), ss);
2138 break; /* AUTH_CMD */
2140 /* The HELO/EHLO commands are permitted to appear in the middle of a
2141 session as well as at the beginning. They have the effect of a reset in
2142 addition to their other functions. Their absence at the start cannot be
2143 taken to be an error.
2147 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2148 or 502 failure replies MUST be returned as appropriate. The SMTP
2149 server MUST stay in the same state after transmitting these replies
2150 that it was in before the EHLO was received.
2152 Therefore, we do not do the reset until after checking the command for
2153 acceptability. This change was made for Exim release 4.11. Previously
2154 it did the reset first. */
2165 HELO_EHLO: /* Common code for HELO and EHLO */
2166 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2167 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2169 /* Reject the HELO if its argument was invalid or non-existent. A
2170 successful check causes the argument to be saved in malloc store. */
2172 if (!check_helo(smtp_data))
2174 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2176 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2177 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2178 (*smtp_data == 0)? US"(no argument given)" :
2179 string_printing(smtp_data));
2181 if (++synprot_error_count > smtp_max_synprot_errors)
2183 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2184 "syntax or protocol errors (last command was \"%s\")",
2185 host_and_ident(FALSE), cmd_buffer);
2192 /* If sender_host_unknown is true, we have got here via the -bs interface,
2193 not called from inetd. Otherwise, we are running an IP connection and the
2194 host address will be set. If the helo name is the primary name of this
2195 host and we haven't done a reverse lookup, force one now. If helo_required
2196 is set, ensure that the HELO name matches the actual host. If helo_verify
2197 is set, do the same check, but softly. */
2199 if (!sender_host_unknown)
2201 BOOL old_helo_verified = helo_verified;
2202 uschar *p = smtp_data;
2204 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2207 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2208 because otherwise the log can be confusing. */
2210 if (sender_host_name == NULL &&
2211 (deliver_domain = sender_helo_name, /* set $domain */
2212 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2213 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2214 (void)host_name_lookup();
2216 /* Rebuild the fullhost info to include the HELO name (and the real name
2217 if it was looked up.) */
2219 host_build_sender_fullhost(); /* Rebuild */
2220 set_process_info("handling%s incoming connection from %s",
2221 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2223 /* Verify if configured. This doesn't give much security, but it does
2224 make some people happy to be able to do it. Note that HELO is legitimately
2225 allowed to quote an address literal. Allow for IPv6 ::ffff: literals. */
2227 helo_verified = FALSE;
2228 if (helo_required || helo_verify)
2230 BOOL tempfail = FALSE;
2232 HDEBUG(D_receive) debug_printf("verifying %s %s\n", hello,
2234 if (sender_helo_name[0] == '[')
2236 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2237 Ustrlen(sender_host_address)) == 0;
2242 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2243 helo_verified = Ustrncmp(sender_helo_name + 1,
2244 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2249 { if (helo_verified) debug_printf("matched host address\n"); }
2252 /* Do a reverse lookup if one hasn't already given a positive or
2253 negative response. If that fails, or the name doesn't match, try
2254 checking with a forward lookup. */
2258 if (sender_host_name == NULL && !host_lookup_failed)
2259 tempfail = host_name_lookup() == DEFER;
2261 /* If a host name is known, check it and all its aliases. */
2263 if (sender_host_name != NULL)
2265 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2269 HDEBUG(D_receive) debug_printf("matched host name\n");
2273 uschar **aliases = sender_host_aliases;
2274 while (*aliases != NULL)
2276 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2277 if (helo_verified) break;
2282 debug_printf("matched alias %s\n", *(--aliases));
2287 /* Final attempt: try a forward lookup of the helo name */
2293 h.name = sender_helo_name;
2297 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2299 rc = host_find_byname(&h, NULL, NULL, TRUE);
2300 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2305 if (Ustrcmp(hh->address, sender_host_address) == 0)
2307 helo_verified = TRUE;
2309 debug_printf("IP address for %s matches calling address\n",
2319 /* Verification failed. A temporary lookup failure gives a temporary
2326 smtp_printf("%d %s argument does not match calling host\r\n",
2327 tempfail? 451 : 550, hello);
2328 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2329 tempfail? "temporarily " : "",
2330 hello, sender_helo_name, host_and_ident(FALSE));
2331 helo_verified = old_helo_verified;
2332 break; /* End of HELO/EHLO processing */
2334 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2335 "helo_try_verify_hosts\n", hello);
2340 /* Apply an ACL check if one is defined */
2342 if (acl_smtp_helo != NULL)
2344 rc = acl_check(ACL_WHERE_HELO, smtp_data, acl_smtp_helo, &user_msg,
2348 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2349 sender_helo_name = NULL;
2350 host_build_sender_fullhost(); /* Rebuild */
2355 /* The EHLO/HELO command is acceptable. Reset the protocol and the state,
2356 abandoning any previous message. */
2358 received_protocol = (esmtp?
2360 ((sender_host_authenticated != NULL)? pauthed : 0) +
2361 ((tls_active >= 0)? pcrpted : 0)]
2365 ((sender_host_address != NULL)? pnlocal : 0);
2367 smtp_reset(reset_point);
2370 /* Generate an OK reply, including the ident if present, and also
2371 the IP address if present. Reflecting back the ident is intended
2372 as a deterrent to mail forgers. For maximum efficiency, and also
2373 because some broken systems expect each response to be in a single
2374 packet, arrange that it is sent in one write(). */
2376 auth_advertised = FALSE;
2377 pipelining_advertised = FALSE;
2379 tls_advertised = FALSE;
2382 s = string_sprintf("250 %s Hello %s%s%s",
2383 smtp_active_hostname,
2384 (sender_ident == NULL)? US"" : sender_ident,
2385 (sender_ident == NULL)? US"" : US" at ",
2386 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2391 if (sender_host_address != NULL)
2393 s = string_cat(s, &size, &ptr, US" [", 2);
2394 s = string_cat(s, &size, &ptr, sender_host_address,
2395 Ustrlen(sender_host_address));
2396 s = string_cat(s, &size, &ptr, US"]", 1);
2399 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2401 /* If we received EHLO, we must create a multiline response which includes
2402 the functions supported. */
2408 /* I'm not entirely happy with this, as an MTA is supposed to check
2409 that it has enough room to accept a message of maximum size before
2410 it sends this. However, there seems little point in not sending it.
2411 The actual size check happens later at MAIL FROM time. By postponing it
2412 till then, VRFY and EXPN can be used after EHLO when space is short. */
2414 if (thismessage_size_limit > 0)
2416 sprintf(CS big_buffer, "250-SIZE %d\r\n", thismessage_size_limit);
2417 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2421 s = string_cat(s, &size, &ptr, US"250-SIZE\r\n", 10);
2424 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2425 clean; if it has an 8-bit character in its hand, it just sends it. It
2426 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2427 However, some users want this option simply in order to stop MUAs
2428 mangling messages that contain top-bit-set characters. It is therefore
2429 provided as an option. */
2431 if (accept_8bitmime)
2432 s = string_cat(s, &size, &ptr, US"250-8BITMIME\r\n", 14);
2434 /* Advertise ETRN if there's an ACL checking whether a host is
2435 permitted to issue it; a check is made when any host actually tries. */
2437 if (acl_smtp_etrn != NULL)
2439 s = string_cat(s, &size, &ptr, US"250-ETRN\r\n", 10);
2442 /* Advertise EXPN if there's an ACL checking whether a host is
2443 permitted to issue it; a check is made when any host actually tries. */
2445 if (acl_smtp_expn != NULL)
2447 s = string_cat(s, &size, &ptr, US"250-EXPN\r\n", 10);
2450 /* Exim is quite happy with pipelining, so let the other end know that
2451 it is safe to use it, unless advertising is disabled. */
2453 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2455 s = string_cat(s, &size, &ptr, US"250-PIPELINING\r\n", 16);
2456 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2457 pipelining_advertised = TRUE;
2460 /* If any server authentication mechanisms are configured, advertise
2461 them if the current host is in auth_advertise_hosts. The problem with
2462 advertising always is that some clients then require users to
2463 authenticate (and aren't configurable otherwise) even though it may not
2464 be necessary (e.g. if the host is in host_accept_relay).
2466 RFC 2222 states that SASL mechanism names contain only upper case
2467 letters, so output the names in upper case, though we actually recognize
2468 them in either case in the AUTH command. */
2472 if (verify_check_host(&auth_advertise_hosts) == OK)
2476 for (au = auths; au != NULL; au = au->next)
2478 if (au->server && (au->advertise_condition == NULL ||
2479 expand_check_condition(au->advertise_condition, au->name,
2480 US"authenticator")))
2485 s = string_cat(s, &size, &ptr, US"250-AUTH", 8);
2487 auth_advertised = TRUE;
2490 s = string_cat(s, &size, &ptr, US" ", 1);
2491 s = string_cat(s, &size, &ptr, au->public_name,
2492 Ustrlen(au->public_name));
2493 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2494 au->advertised = TRUE;
2496 else au->advertised = FALSE;
2498 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2502 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2503 if it has been included in the binary, and the host matches
2504 tls_advertise_hosts. We must *not* advertise if we are already in a
2505 secure connection. */
2508 if (tls_active < 0 &&
2509 verify_check_host(&tls_advertise_hosts) != FAIL)
2511 s = string_cat(s, &size, &ptr, US"250-STARTTLS\r\n", 14);
2512 tls_advertised = TRUE;
2516 /* Finish off the multiline reply with one that is always available. */
2518 s = string_cat(s, &size, &ptr, US"250 HELP\r\n", 10);
2521 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2527 if (tls_active >= 0) (void)tls_write(s, ptr); else
2530 fwrite(s, 1, ptr, smtp_out);
2531 DEBUG(D_receive) debug_printf("SMTP>> %s", s);
2533 break; /* HELO/EHLO */
2536 /* The MAIL command requires an address as an operand. All we do
2537 here is to parse it for syntactic correctness. The form "<>" is
2538 a special case which converts into an empty string. The start/end
2539 pointers in the original are not used further for this address, as
2540 it is the canonical extracted address which is all that is kept. */
2543 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2544 was_rej_mail = TRUE; /* Reset if accepted */
2546 if (helo_required && !helo_seen)
2548 smtp_printf("503 HELO or EHLO required\r\n");
2549 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2550 "HELO/EHLO given", host_and_ident(FALSE));
2554 if (sender_address != NULL)
2556 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2557 US"sender already given");
2561 if (smtp_data[0] == 0)
2563 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2564 US"MAIL must have an address operand");
2568 /* Check to see if the limit for messages per connection would be
2569 exceeded by accepting further messages. */
2571 if (smtp_accept_max_per_connection > 0 &&
2572 smtp_mailcmd_count > smtp_accept_max_per_connection)
2574 smtp_printf("421 too many messages in this connection\r\n");
2575 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2576 "messages in one connection", host_and_ident(TRUE));
2580 /* Reset for start of message - even if this is going to fail, we
2581 obviously need to throw away any previous data. */
2583 smtp_reset(reset_point);
2585 sender_data = recipient_data = NULL;
2587 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2591 uschar *name, *value, *end;
2592 unsigned long int size;
2594 if (!extract_option(&name, &value)) break;
2596 /* Handle SIZE= by reading the value. We don't do the check till later,
2597 in order to be able to log the sender address on failure. */
2599 if (strcmpic(name, US"SIZE") == 0 &&
2600 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2602 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2604 message_size = (int)size;
2607 /* If this session was initiated with EHLO and accept_8bitmime is set,
2608 Exim will have indicated that it supports the BODY=8BITMIME option. In
2609 fact, it does not support this according to the RFCs, in that it does not
2610 take any special action for forwarding messages containing 8-bit
2611 characters. That is why accept_8bitmime is not the default setting, but
2612 some sites want the action that is provided. We recognize both "8BITMIME"
2613 and "7BIT" as body types, but take no action. */
2615 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2616 (strcmpic(value, US"8BITMIME") == 0 ||
2617 strcmpic(value, US"7BIT") == 0)) {}
2619 /* Handle the AUTH extension. If the value given is not "<>" and either
2620 the ACL says "yes" or there is no ACL but the sending host is
2621 authenticated, we set it up as the authenticated sender. However, if the
2622 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2623 the condition is met. The value of AUTH is an xtext, which means that +,
2624 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2627 else if (strcmpic(name, US"AUTH") == 0)
2629 if (Ustrcmp(value, "<>") != 0)
2634 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2636 /* Put back terminator overrides for error message */
2639 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2640 US"invalid data for AUTH");
2644 if (acl_smtp_mailauth == NULL)
2646 ignore_msg = US"client not authenticated";
2647 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2651 ignore_msg = US"rejected by ACL";
2652 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2653 &user_msg, &log_msg);
2659 if (authenticated_by == NULL ||
2660 authenticated_by->mail_auth_condition == NULL ||
2661 expand_check_condition(authenticated_by->mail_auth_condition,
2662 authenticated_by->name, US"authenticator"))
2663 break; /* Accept the AUTH */
2665 ignore_msg = US"server_mail_auth_condition failed";
2666 if (authenticated_id != NULL)
2667 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2668 ignore_msg, authenticated_id);
2673 authenticated_sender = NULL;
2674 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
2675 value, host_and_ident(TRUE), ignore_msg);
2678 /* Should only get DEFER or ERROR here. Put back terminator
2679 overrides for error message */
2684 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
2691 /* Unknown option. Stick back the terminator characters and break
2692 the loop. An error for a malformed address will occur. */
2702 /* If we have passed the threshold for rate limiting, apply the current
2703 delay, and update it for next time, provided this is a limited host. */
2705 if (smtp_mailcmd_count > smtp_rlm_threshold &&
2706 verify_check_host(&smtp_ratelimit_hosts) == OK)
2708 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
2709 smtp_delay_mail/1000.0);
2710 millisleep((int)smtp_delay_mail);
2711 smtp_delay_mail *= smtp_rlm_factor;
2712 if (smtp_delay_mail > (double)smtp_rlm_limit)
2713 smtp_delay_mail = (double)smtp_rlm_limit;
2716 /* Now extract the address, first applying any SMTP-time rewriting. The
2717 TRUE flag allows "<>" as a sender address. */
2719 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2720 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2721 global_rewrite_rules) : smtp_data;
2723 /* rfc821_domains = TRUE; << no longer needed */
2725 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2727 /* rfc821_domains = FALSE; << no longer needed */
2729 if (raw_sender == NULL)
2731 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2735 sender_address = raw_sender;
2737 /* If there is a configured size limit for mail, check that this message
2738 doesn't exceed it. The check is postponed to this point so that the sender
2741 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
2743 smtp_printf("552 Message size exceeds maximum permitted\r\n");
2744 log_write(L_size_reject,
2745 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
2746 "message too big: size%s=%d max=%d",
2748 host_and_ident(TRUE),
2749 (message_size == INT_MAX)? ">" : "",
2751 thismessage_size_limit);
2752 sender_address = NULL;
2756 /* Check there is enough space on the disk unless configured not to.
2757 When smtp_check_spool_space is set, the check is for thismessage_size_limit
2758 plus the current message - i.e. we accept the message only if it won't
2759 reduce the space below the threshold. Add 5000 to the size to allow for
2760 overheads such as the Received: line and storing of recipients, etc.
2761 By putting the check here, even when SIZE is not given, it allow VRFY
2762 and EXPN etc. to be used when space is short. */
2764 if (!receive_check_fs(
2765 (smtp_check_spool_space && message_size >= 0)?
2766 message_size + 5000 : 0))
2768 smtp_printf("452 Space shortage, please try later\r\n");
2769 sender_address = NULL;
2773 /* If sender_address is unqualified, reject it, unless this is a locally
2774 generated message, or the sending host or net is permitted to send
2775 unqualified addresses - typically local machines behaving as MUAs -
2776 in which case just qualify the address. The flag is set above at the start
2777 of the SMTP connection. */
2779 if (sender_domain == 0 && sender_address[0] != 0)
2781 if (allow_unqualified_sender)
2783 sender_domain = Ustrlen(sender_address) + 1;
2784 sender_address = rewrite_address_qualify(sender_address, FALSE);
2785 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2790 smtp_printf("501 %s: sender address must contain a domain\r\n",
2792 log_write(L_smtp_syntax_error,
2793 LOG_MAIN|LOG_REJECT,
2794 "unqualified sender rejected: <%s> %s%s",
2796 host_and_ident(TRUE),
2798 sender_address = NULL;
2803 /* Apply an ACL check if one is defined, before responding */
2805 rc = (acl_smtp_mail == NULL)? OK :
2806 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
2808 if (rc == OK || rc == DISCARD)
2810 smtp_printf("250 OK\r\n");
2811 smtp_delay_rcpt = smtp_rlr_base;
2812 recipients_discarded = (rc == DISCARD);
2813 was_rej_mail = FALSE;
2818 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
2819 sender_address = NULL;
2824 /* The RCPT command requires an address as an operand. All we do
2825 here is to parse it for syntactic correctness. There may be any number
2826 of RCPT commands, specifying multiple senders. We build them all into
2827 a data structure that is in argc/argv format. The start/end values
2828 given by parse_extract_address are not used, as we keep only the
2829 extracted address. */
2835 /* There must be a sender address; if the sender was rejected and
2836 pipelining was advertised, we assume the client was pipelining, and do not
2837 count this as a protocol error. Reset was_rej_mail so that further RCPTs
2838 get the same treatment. */
2840 if (sender_address == NULL)
2842 if (pipelining_advertised && last_was_rej_mail)
2844 smtp_printf("503 sender not yet given\r\n");
2845 was_rej_mail = TRUE;
2849 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2850 US"sender not yet given");
2851 was_rcpt = FALSE; /* Not a valid RCPT */
2857 /* Check for an operand */
2859 if (smtp_data[0] == 0)
2861 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2862 US"RCPT must have an address operand");
2867 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
2868 as a recipient address */
2870 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
2871 rewrite_one(smtp_data, rewrite_smtp, NULL, FALSE, US"",
2872 global_rewrite_rules) : smtp_data;
2874 /* rfc821_domains = TRUE; << no longer needed */
2875 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2876 &recipient_domain, FALSE);
2877 /* rfc821_domains = FALSE; << no longer needed */
2879 if (recipient == NULL)
2881 done = synprot_error(L_smtp_syntax_error, 501, smtp_data, errmess);
2886 /* If the recipient address is unqualified, reject it, unless this is a
2887 locally generated message. However, unqualified addresses are permitted
2888 from a configured list of hosts and nets - typically when behaving as
2889 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
2890 really. The flag is set at the start of the SMTP connection.
2892 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
2893 assumed this meant "reserved local part", but the revision of RFC 821 and
2894 friends now makes it absolutely clear that it means *mailbox*. Consequently
2895 we must always qualify this address, regardless. */
2897 if (recipient_domain == 0)
2899 if (allow_unqualified_recipient ||
2900 strcmpic(recipient, US"postmaster") == 0)
2902 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2904 recipient_domain = Ustrlen(recipient) + 1;
2905 recipient = rewrite_address_qualify(recipient, TRUE);
2910 smtp_printf("501 %s: recipient address must contain a domain\r\n",
2912 log_write(L_smtp_syntax_error,
2913 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
2914 "<%s> %s%s", recipient, host_and_ident(TRUE),
2920 /* Check maximum allowed */
2922 if (rcpt_count > recipients_max && recipients_max > 0)
2924 if (recipients_max_reject)
2927 smtp_printf("552 too many recipients\r\n");
2929 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
2930 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
2935 smtp_printf("452 too many recipients\r\n");
2937 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
2938 "temporarily rejected: sender=<%s> %s", sender_address,
2939 host_and_ident(TRUE));
2946 /* If we have passed the threshold for rate limiting, apply the current
2947 delay, and update it for next time, provided this is a limited host. */
2949 if (rcpt_count > smtp_rlr_threshold &&
2950 verify_check_host(&smtp_ratelimit_hosts) == OK)
2952 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
2953 smtp_delay_rcpt/1000.0);
2954 millisleep((int)smtp_delay_rcpt);
2955 smtp_delay_rcpt *= smtp_rlr_factor;
2956 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
2957 smtp_delay_rcpt = (double)smtp_rlr_limit;
2960 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
2961 for them. Otherwise, check the access control list for this recipient. */
2963 rc = recipients_discarded? DISCARD :
2964 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
2966 /* The ACL was happy */
2970 smtp_printf("250 Accepted\r\n");
2971 receive_add_recipient(recipient, -1);
2974 /* The recipient was discarded */
2976 else if (rc == DISCARD)
2978 smtp_printf("250 Accepted\r\n");
2981 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
2982 "discarded by %s ACL%s%s", host_and_ident(TRUE),
2983 (sender_address_unrewritten != NULL)?
2984 sender_address_unrewritten : sender_address,
2985 smtp_data, recipients_discarded? "MAIL" : "RCPT",
2986 (log_msg == NULL)? US"" : US": ",
2987 (log_msg == NULL)? US"" : log_msg);
2990 /* Either the ACL failed the address, or it was deferred. */
2994 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
2995 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3000 /* The DATA command is legal only if it follows successful MAIL FROM
3001 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3002 not counted as a protocol error if it follows RCPT (which must have been
3003 rejected if there are no recipients.) This function is complete when a
3004 valid DATA command is encountered.
3006 Note concerning the code used: RFC 2821 says this:
3008 - If there was no MAIL, or no RCPT, command, or all such commands
3009 were rejected, the server MAY return a "command out of sequence"
3010 (503) or "no valid recipients" (554) reply in response to the
3013 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3014 because it is the same whether pipelining is in use or not. */
3017 if (!discarded && recipients_count <= 0)
3019 if (pipelining_advertised && last_was_rcpt)
3020 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3022 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3023 US"valid RCPT command must precede DATA");
3027 if (toomany && recipients_max_reject)
3029 sender_address = NULL; /* This will allow a new MAIL without RSET */
3030 sender_address_unrewritten = NULL;
3031 smtp_printf("554 Too many recipients\r\n");
3035 rc = (acl_smtp_predata == NULL)? OK :
3036 acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg, &log_msg);
3040 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3042 message_ended = END_NOTENDED; /* Indicate in middle of data */
3045 /* Either the ACL failed the address, or it was deferred. */
3048 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3054 rc = acl_check(ACL_WHERE_VRFY, smtp_data, acl_smtp_vrfy, &user_msg,
3057 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3063 /* rfc821_domains = TRUE; << no longer needed */
3064 address = parse_extract_address(smtp_data, &errmess, &start, &end,
3065 &recipient_domain, FALSE);
3066 /* rfc821_domains = FALSE; << no longer needed */
3068 if (address == NULL)
3069 s = string_sprintf("501 %s", errmess);
3072 address_item *addr = deliver_make_addr(address, FALSE);
3073 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3074 -1, NULL, NULL, NULL))
3077 s = string_sprintf("250 <%s> is deliverable", address);
3081 s = (addr->message != NULL)?
3082 string_sprintf("451 <%s> %s", address, addr->message) :
3083 string_sprintf("451 Cannot resolve <%s> at this time", address);
3087 s = (addr->message != NULL)?
3088 string_sprintf("550 <%s> %s", address, addr->message) :
3089 string_sprintf("550 <%s> is not deliverable", address);
3090 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3091 smtp_data, host_and_ident(TRUE));
3096 smtp_printf("%s\r\n", s);
3102 rc = acl_check(ACL_WHERE_EXPN, smtp_data, acl_smtp_expn, &user_msg,
3105 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3108 BOOL save_log_testing_mode = log_testing_mode;
3109 address_test_mode = log_testing_mode = TRUE;
3110 (void) verify_address(deliver_make_addr(smtp_data, FALSE), smtp_out,
3111 vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, NULL, NULL, NULL);
3112 address_test_mode = FALSE;
3113 log_testing_mode = save_log_testing_mode; /* true for -bh */
3121 if (!tls_advertised)
3123 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3124 US"STARTTLS command used when not advertised");
3128 /* Apply an ACL check if one is defined */
3130 if (acl_smtp_starttls != NULL)
3132 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3136 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3141 /* RFC 2487 is not clear on when this command may be sent, though it
3142 does state that all information previously obtained from the client
3143 must be discarded if a TLS session is started. It seems reasonble to
3144 do an implied RSET when STARTTLS is received. */
3146 incomplete_transaction_log(US"STARTTLS");
3147 smtp_reset(reset_point);
3149 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3151 /* Attempt to start up a TLS session, and if successful, discard all
3152 knowledge that was obtained previously. At least, that's what the RFC says,
3153 and that's what happens by default. However, in order to work round YAEB,
3154 there is an option to remember the esmtp state. Sigh.
3156 We must allow for an extra EHLO command and an extra AUTH command after
3157 STARTTLS that don't add to the nonmail command count. */
3159 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3161 if (!tls_remember_esmtp)
3162 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3163 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3164 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3165 if (sender_helo_name != NULL)
3167 store_free(sender_helo_name);
3168 sender_helo_name = NULL;
3169 host_build_sender_fullhost(); /* Rebuild */
3170 set_process_info("handling incoming TLS connection from %s",
3171 host_and_ident(FALSE));
3173 received_protocol = (esmtp?
3174 protocols[pextend + pcrpted +
3175 ((sender_host_authenticated != NULL)? pauthed : 0)]
3179 ((sender_host_address != NULL)? pnlocal : 0);
3181 sender_host_authenticated = NULL;
3182 authenticated_id = NULL;
3183 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3184 DEBUG(D_tls) debug_printf("TLS active\n");
3185 break; /* Successful STARTTLS */
3188 /* Some local configuration problem was discovered before actually trying
3189 to do a TLS handshake; give a temporary error. */
3191 else if (rc == DEFER)
3193 smtp_printf("454 TLS currently unavailable\r\n");
3197 /* Hard failure. Reject everything except QUIT or closed connection. One
3198 cause for failure is a nested STARTTLS, in which case tls_active remains
3199 set, but we must still reject all incoming commands. */
3201 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3204 switch(smtp_read_command(FALSE))
3207 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3208 smtp_get_connection_info());
3213 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3214 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3215 smtp_get_connection_info());
3220 smtp_printf("554 Security failure\r\n");
3229 /* The ACL for QUIT is provided for gathering statistical information or
3230 similar; it does not affect the response code, but it can supply a custom
3234 incomplete_transaction_log(US"QUIT");
3236 if (acl_smtp_quit != NULL)
3238 rc = acl_check(ACL_WHERE_QUIT, US"", acl_smtp_quit,&user_msg,&log_msg);
3240 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3243 else user_msg = NULL;
3245 if (user_msg == NULL)
3246 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3248 smtp_printf("221 %s\r\n", user_msg);
3255 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3256 smtp_get_connection_info());
3261 incomplete_transaction_log(US"RSET");
3262 smtp_reset(reset_point);
3264 smtp_printf("250 Reset OK\r\n");
3265 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3270 smtp_printf("250 OK\r\n");
3274 /* Show ETRN/EXPN/VRFY if there's
3275 an ACL for checking hosts; if actually used, a check will be done for
3279 smtp_printf("214-Commands supported:\r\n");
3283 Ustrcat(buffer, " AUTH");
3285 Ustrcat(buffer, " STARTTLS");
3287 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3288 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3289 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3290 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3291 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3292 smtp_printf("214%s\r\n", buffer);
3298 incomplete_transaction_log(US"connection lost");
3299 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3301 /* Don't log by default unless in the middle of a message, as some mailers
3302 just drop the call rather than sending QUIT, and it clutters up the logs.
3305 if (sender_address != NULL || recipients_count > 0)
3306 log_write(L_lost_incoming_connection,
3308 "unexpected %s while reading SMTP command from %s%s",
3309 sender_host_unknown? "EOF" : "disconnection",
3310 host_and_ident(FALSE), smtp_read_error);
3312 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3313 smtp_get_connection_info(), smtp_read_error);
3320 if (sender_address != NULL)
3322 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3323 US"ETRN is not permitted inside a transaction");
3327 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_data,
3328 host_and_ident(FALSE));
3330 rc = acl_check(ACL_WHERE_ETRN, smtp_data, acl_smtp_etrn, &user_msg,
3334 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3338 /* Compute the serialization key for this command. */
3340 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_data);
3342 /* If a command has been specified for running as a result of ETRN, we
3343 permit any argument to ETRN. If not, only the # standard form is permitted,
3344 since that is strictly the only kind of ETRN that can be implemented
3345 according to the RFC. */
3347 if (smtp_etrn_command != NULL)
3351 etrn_command = smtp_etrn_command;
3352 deliver_domain = smtp_data;
3353 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3354 US"ETRN processing", &error);
3355 deliver_domain = NULL;
3358 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3360 smtp_printf("458 Internal failure\r\n");
3365 /* Else set up to call Exim with the -R option. */
3369 if (*smtp_data++ != '#')
3371 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3372 US"argument must begin with #");
3375 etrn_command = US"exim -R";
3376 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3380 /* If we are host-testing, don't actually do anything. */
3386 debug_printf("ETRN command is: %s\n", etrn_command);
3387 debug_printf("ETRN command execution skipped\n");
3389 smtp_printf("250 OK\r\n");
3394 /* If ETRN queue runs are to be serialized, check the database to
3395 ensure one isn't already running. */
3397 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3399 smtp_printf("458 Already processing %s\r\n", smtp_data);
3403 /* Fork a child process and run the command. We don't want to have to
3404 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3405 forking. It should be set that way anyway for external incoming SMTP,
3406 but we save and restore to be tidy. If serialization is required, we
3407 actually run the command in yet another process, so we can wait for it
3408 to complete and then remove the serialization lock. */
3410 oldsignal = signal(SIGCHLD, SIG_IGN);
3412 if ((pid = fork()) == 0)
3414 smtp_input = FALSE; /* This process is not associated with the */
3415 fclose(smtp_in); /* SMTP call any more. */
3418 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3420 /* If not serializing, do the exec right away. Otherwise, fork down
3421 into another process. */
3423 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3425 DEBUG(D_exec) debug_print_argv(argv);
3426 exim_nullstd(); /* Ensure std{in,out,err} exist */
3427 execv(CS argv[0], (char *const *)argv);
3428 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3429 etrn_command, strerror(errno));
3430 _exit(EXIT_FAILURE); /* paranoia */
3433 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3434 is, we are in the first subprocess, after forking again. All we can do
3435 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3436 complete, before removing the serialization. */
3439 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3440 "failed: %s", strerror(errno));
3444 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3446 (void)wait(&status);
3447 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3451 enq_end(etrn_serialize_key);
3452 _exit(EXIT_SUCCESS);
3455 /* Back in the top level SMTP process. Check that we started a subprocess
3456 and restore the signal state. */
3460 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3462 smtp_printf("458 Unable to fork process\r\n");
3463 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3465 else smtp_printf("250 OK\r\n");
3467 signal(SIGCHLD, oldsignal);
3472 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3473 US"unexpected argument data");
3477 /* This currently happens only for NULLs, but could be extended. */
3480 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3481 US"NULL character(s) present (shown as '?')");
3482 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3487 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3488 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3489 c = smtp_inend - smtp_inptr;
3490 if (c > 150) c = 150;
3492 incomplete_transaction_log(US"sync failure");
3493 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol violation: "
3494 "synchronization error "
3495 "(next input sent too soon: pipelining was%s advertised): "
3496 "rejected \"%s\" %s next input=\"%s\"",
3497 pipelining_advertised? "" : " not",
3498 cmd_buffer, host_and_ident(TRUE),
3499 string_printing(smtp_inptr));
3500 smtp_printf("554 SMTP synchronization error\r\n");
3501 done = 1; /* Pretend eof - drops connection */
3505 case TOO_MANY_NONMAIL_CMD:
3506 incomplete_transaction_log(US"too many non-mail commands");
3507 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3508 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
3509 smtp_data - cmd_buffer, cmd_buffer);
3510 smtp_printf("554 Too many nonmail commands\r\n");
3511 done = 1; /* Pretend eof - drops connection */
3516 if (unknown_command_count++ >= smtp_max_unknown_commands)
3518 log_write(L_smtp_syntax_error, LOG_MAIN,
3519 "SMTP syntax error in \"%s\" %s %s",
3520 string_printing(cmd_buffer), host_and_ident(TRUE),
3521 US"unrecognized command");
3522 incomplete_transaction_log(US"unrecognized command");
3523 smtp_printf("500 Too many unrecognized commands\r\n");
3525 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3526 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3530 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3531 US"unrecognized command");
3535 /* This label is used by goto's inside loops that want to break out to
3536 the end of the command-processing loop. */
3539 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3540 last_was_rcpt = was_rcpt; /* protocol error handling */
3544 return done - 2; /* Convert yield values */
3547 /* End of smtp_in.c */