1 /* $Cambridge: exim/src/src/smtp_in.c,v 1.47 2006/11/14 16:40:36 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2006 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. */
42 #define smtp_cmd_buffer_size 2048
44 /* Size of buffer for reading SMTP incoming packets */
46 #define in_buffer_size 8192
48 /* Structure for SMTP command list */
55 short int is_mail_cmd;
58 /* Codes for identifying commands. We order them so that those that come first
59 are those for which synchronization is always required. Checking this can help
63 /* These commands are required to be synchronized, i.e. to be the last in a
64 block of commands when pipelining. */
66 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
67 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
68 ETRN_CMD, /* This by analogy with TURN from the RFC */
69 STARTTLS_CMD, /* Required by the STARTTLS RFC */
71 /* This is a dummy to identify the non-sync commands when pipelining */
73 NON_SYNC_CMD_PIPELINING,
75 /* These commands need not be synchronized when pipelining */
77 MAIL_CMD, RCPT_CMD, RSET_CMD,
79 /* This is a dummy to identify the non-sync commands when not pipelining */
81 NON_SYNC_CMD_NON_PIPELINING,
83 /* I have been unable to find a statement about the use of pipelining
84 with AUTH, so to be on the safe side it is here, though I kind of feel
85 it should be up there with the synchronized commands. */
89 /* I'm not sure about these, but I don't think they matter. */
93 /* These are specials that don't correspond to actual commands */
95 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
96 TOO_MANY_NONMAIL_CMD };
100 /*************************************************
101 * Local static variables *
102 *************************************************/
104 static auth_instance *authenticated_by;
105 static BOOL auth_advertised;
107 static BOOL tls_advertised;
110 static BOOL helo_required = FALSE;
111 static BOOL helo_verify = FALSE;
112 static BOOL helo_seen;
113 static BOOL helo_accept_junk;
114 static BOOL count_nonmail;
115 static BOOL pipelining_advertised;
116 static int nonmail_command_count;
117 static int synprot_error_count;
118 static int unknown_command_count;
119 static int sync_cmd_limit;
120 static int smtp_write_error = 0;
122 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
123 final fields of all except AUTH are forced TRUE at the start of a new message
124 setup, to allow one of each between messages that is not counted as a nonmail
125 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
126 allow a new EHLO after starting up TLS.
128 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
129 counted. However, the flag is changed when AUTH is received, so that multiple
130 failing AUTHs will eventually hit the limit. After a successful AUTH, another
131 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
132 forced TRUE, to allow for the re-authentication that can happen at that point.
134 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
135 count of non-mail commands and possibly provoke an error. */
137 static smtp_cmd_list cmd_list[] = {
138 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
139 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
140 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
141 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
143 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
146 /* If you change anything above here, also fix the definitions below. */
148 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
149 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
150 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
151 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
152 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
153 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
154 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
155 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
156 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
159 static smtp_cmd_list *cmd_list_end =
160 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
162 #define CMD_LIST_RSET 0
163 #define CMD_LIST_HELO 1
164 #define CMD_LIST_EHLO 2
165 #define CMD_LIST_AUTH 3
166 #define CMD_LIST_STARTTLS 4
168 static uschar *protocols[] = {
169 US"local-smtp", /* HELO */
170 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
171 US"local-esmtp", /* EHLO */
172 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
173 US"local-esmtpa", /* EHLO->AUTH */
174 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
179 #define pcrpted 1 /* added to pextend or pnormal */
180 #define pauthed 2 /* added to pextend */
181 #define pnlocal 6 /* offset to remove "local" */
183 /* When reading SMTP from a remote host, we have to use our own versions of the
184 C input-reading functions, in order to be able to flush the SMTP output only
185 when about to read more data from the socket. This is the only way to get
186 optimal performance when the client is using pipelining. Flushing for every
187 command causes a separate packet and reply packet each time; saving all the
188 responses up (when pipelining) combines them into one packet and one response.
190 For simplicity, these functions are used for *all* SMTP input, not only when
191 receiving over a socket. However, after setting up a secure socket (SSL), input
192 is read via the OpenSSL library, and another set of functions is used instead
195 These functions are set in the receive_getc etc. variables and called with the
196 same interface as the C functions. However, since there can only ever be
197 one incoming SMTP call, we just use a single buffer and flags. There is no need
198 to implement a complicated private FILE-like structure.*/
200 static uschar *smtp_inbuffer;
201 static uschar *smtp_inptr;
202 static uschar *smtp_inend;
203 static int smtp_had_eof;
204 static int smtp_had_error;
207 /*************************************************
208 * SMTP version of getc() *
209 *************************************************/
211 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
212 it flushes the output, and refills the buffer, with a timeout. The signal
213 handler is set appropriately by the calling function. This function is not used
214 after a connection has negotated itself into an TLS/SSL state.
217 Returns: the next character or EOF
223 if (smtp_inptr >= smtp_inend)
227 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
228 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
233 /* Must put the error text in fixed store, because this might be during
234 header reading, where it releases unused store above the header. */
237 smtp_had_error = save_errno;
238 smtp_read_error = string_copy_malloc(
239 string_sprintf(" (error: %s)", strerror(save_errno)));
241 else smtp_had_eof = 1;
244 smtp_inend = smtp_inbuffer + rc;
245 smtp_inptr = smtp_inbuffer;
247 return *smtp_inptr++;
252 /*************************************************
253 * SMTP version of ungetc() *
254 *************************************************/
256 /* Puts a character back in the input buffer. Only ever
262 Returns: the character
268 *(--smtp_inptr) = ch;
275 /*************************************************
276 * SMTP version of feof() *
277 *************************************************/
279 /* Tests for a previous EOF
282 Returns: non-zero if the eof flag is set
294 /*************************************************
295 * SMTP version of ferror() *
296 *************************************************/
298 /* Tests for a previous read error, and returns with errno
299 restored to what it was when the error was detected.
302 Returns: non-zero if the error flag is set
308 errno = smtp_had_error;
309 return smtp_had_error;
315 /*************************************************
316 * Write formatted string to SMTP channel *
317 *************************************************/
319 /* This is a separate function so that we don't have to repeat everything for
320 TLS support or debugging. It is global so that the daemon and the
321 authentication functions can use it. It does not return any error indication,
322 because major problems such as dropped connections won't show up till an output
323 flush for non-TLS connections. The smtp_fflush() function is available for
324 checking that: for convenience, TLS output errors are remembered here so that
325 they are also picked up later by smtp_fflush().
329 ... optional arguments
335 smtp_printf(char *format, ...)
342 va_start(ap, format);
343 (void) string_vformat(big_buffer, big_buffer_size, format, ap);
345 end = big_buffer + Ustrlen(big_buffer);
346 while ((cr = Ustrchr(big_buffer, '\r')) != NULL) /* lose CRs */
347 memmove(cr, cr + 1, (end--) - cr);
348 debug_printf("SMTP>> %s", big_buffer);
351 va_start(ap, format);
353 /* If in a TLS session we have to format the string, and then write it using a
359 if (!string_vformat(big_buffer, big_buffer_size, format, ap))
361 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
362 smtp_closedown(US"Unexpected error");
363 exim_exit(EXIT_FAILURE);
365 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
370 /* Otherwise, just use the standard library function. */
372 if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
378 /*************************************************
379 * Flush SMTP out and check for error *
380 *************************************************/
382 /* This function isn't currently used within Exim (it detects errors when it
383 tries to read the next SMTP input), but is available for use in local_scan().
384 For non-TLS connections, it flushes the output and checks for errors. For
385 TLS-connections, it checks for a previously-detected TLS write error.
388 Returns: 0 for no error; -1 after an error
394 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
395 return smtp_write_error;
400 /*************************************************
401 * SMTP command read timeout *
402 *************************************************/
404 /* Signal handler for timing out incoming SMTP commands. This attempts to
407 Argument: signal number (SIGALRM)
412 command_timeout_handler(int sig)
414 sig = sig; /* Keep picky compilers happy */
415 log_write(L_lost_incoming_connection,
416 LOG_MAIN, "SMTP command timeout on%s connection from %s",
417 (tls_active >= 0)? " TLS" : "",
418 host_and_ident(FALSE));
419 if (smtp_batched_input)
420 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
421 smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
422 smtp_active_hostname);
424 exim_exit(EXIT_FAILURE);
429 /*************************************************
431 *************************************************/
433 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
435 Argument: signal number (SIGTERM)
440 command_sigterm_handler(int sig)
442 sig = sig; /* Keep picky compilers happy */
443 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
444 if (smtp_batched_input)
445 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
446 smtp_printf("421 %s: Service not available - closing connection\r\n",
447 smtp_active_hostname);
448 exim_exit(EXIT_FAILURE);
453 /*************************************************
454 * Read one command line *
455 *************************************************/
457 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
458 There are sites that don't do this, and in any case internal SMTP probably
459 should check only for LF. Consequently, we check here for LF only. The line
460 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
461 an unknown command. The command is read into the global smtp_cmd_buffer so that
462 it is available via $smtp_command.
464 The character reading routine sets up a timeout for each block actually read
465 from the input (which may contain more than one command). We set up a special
466 signal handler that closes down the session on a timeout. Control does not
470 check_sync if TRUE, check synchronization rules if global option is TRUE
472 Returns: a code identifying the command (enumerated above)
476 smtp_read_command(BOOL check_sync)
481 BOOL hadnull = FALSE;
483 os_non_restarting_signal(SIGALRM, command_timeout_handler);
485 while ((c = (receive_getc)()) != '\n' && c != EOF)
487 if (ptr >= smtp_cmd_buffer_size)
489 os_non_restarting_signal(SIGALRM, sigalrm_handler);
497 smtp_cmd_buffer[ptr++] = c;
500 receive_linecount++; /* For BSMTP errors */
501 os_non_restarting_signal(SIGALRM, sigalrm_handler);
503 /* If hit end of file, return pseudo EOF command. Whether we have a
504 part-line already read doesn't matter, since this is an error state. */
506 if (c == EOF) return EOF_CMD;
508 /* Remove any CR and white space at the end of the line, and terminate the
511 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
512 smtp_cmd_buffer[ptr] = 0;
514 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
516 /* NULLs are not allowed in SMTP commands */
518 if (hadnull) return BADCHAR_CMD;
520 /* Scan command list and return identity, having set the data pointer
521 to the start of the actual data characters. Check for SMTP synchronization
524 for (p = cmd_list; p < cmd_list_end; p++)
526 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
527 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
528 smtp_cmd_buffer[p->len] == 0 ||
529 smtp_cmd_buffer[p->len] == ' '))
531 if (smtp_inptr < smtp_inend && /* Outstanding input */
532 p->cmd < sync_cmd_limit && /* Command should sync */
533 check_sync && /* Local flag set */
534 smtp_enforce_sync && /* Global flag set */
535 sender_host_address != NULL && /* Not local input */
536 !sender_host_notsocket) /* Really is a socket */
539 /* Point after the command, but don't skip over leading spaces till after
540 the following test, so that if it fails, the command name can easily be
543 smtp_cmd_argument = smtp_cmd_buffer + p->len;
545 /* Count non-mail commands from those hosts that are controlled in this
546 way. The default is all hosts. We don't waste effort checking the list
547 until we get a non-mail command, but then cache the result to save checking
548 again. If there's a DEFER while checking the host, assume it's in the list.
550 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
551 start of each incoming message by fiddling with the value in the table. */
555 if (count_nonmail == TRUE_UNSET) count_nonmail =
556 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
557 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
558 return TOO_MANY_NONMAIL_CMD;
561 /* Get the data pointer over leading spaces and return; if there is data
562 for a command that does not expect it, give the error centrally here. */
564 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
565 return (p->has_arg || *smtp_cmd_argument == 0)? p->cmd : BADARG_CMD;
569 /* Enforce synchronization for unknown commands */
571 if (smtp_inptr < smtp_inend && /* Outstanding input */
572 check_sync && /* Local flag set */
573 smtp_enforce_sync && /* Global flag set */
574 sender_host_address != NULL && /* Not local input */
575 !sender_host_notsocket) /* Really is a socket */
583 /*************************************************
584 * Forced closedown of call *
585 *************************************************/
587 /* This function is called from log.c when Exim is dying because of a serious
588 disaster, and also from some other places. If an incoming non-batched SMTP
589 channel is open, it swallows the rest of the incoming message if in the DATA
590 phase, sends the reply string, and gives an error to all subsequent commands
591 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
594 Argument: SMTP reply string to send, excluding the code
599 smtp_closedown(uschar *message)
601 if (smtp_in == NULL || smtp_batched_input) return;
602 receive_swallow_smtp();
603 smtp_printf("421 %s\r\n", message);
607 switch(smtp_read_command(FALSE))
613 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
618 smtp_printf("250 Reset OK\r\n");
622 smtp_printf("421 %s\r\n", message);
631 /*************************************************
632 * Set up connection info for logging *
633 *************************************************/
635 /* This function is called when logging information about an SMTP connection.
636 It sets up appropriate source information, depending on the type of connection.
637 If sender_fullhost is NULL, we are at a very early stage of the connection;
638 just use the IP address.
641 Returns: a string describing the connection
645 smtp_get_connection_info(void)
647 uschar *hostname = (sender_fullhost == NULL)?
648 sender_host_address : sender_fullhost;
651 return string_sprintf("SMTP connection from %s", hostname);
653 if (sender_host_unknown || sender_host_notsocket)
654 return string_sprintf("SMTP connection from %s", sender_ident);
657 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
659 if ((log_extra_selector & LX_incoming_interface) != 0 &&
660 interface_address != NULL)
661 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
662 interface_address, interface_port);
664 return string_sprintf("SMTP connection from %s", hostname);
669 /*************************************************
670 * Check HELO line and set sender_helo_name *
671 *************************************************/
673 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
674 the domain name of the sending host, or an ip literal in square brackets. The
675 arrgument is placed in sender_helo_name, which is in malloc store, because it
676 must persist over multiple incoming messages. If helo_accept_junk is set, this
677 host is permitted to send any old junk (needed for some broken hosts).
678 Otherwise, helo_allow_chars can be used for rogue characters in general
679 (typically people want to let in underscores).
682 s the data portion of the line (already past any white space)
684 Returns: TRUE or FALSE
688 check_helo(uschar *s)
691 uschar *end = s + Ustrlen(s);
692 BOOL yield = helo_accept_junk;
694 /* Discard any previous helo name */
696 if (sender_helo_name != NULL)
698 store_free(sender_helo_name);
699 sender_helo_name = NULL;
702 /* Skip tests if junk is permitted. */
706 /* Allow the new standard form for IPv6 address literals, namely,
707 [IPv6:....], and because someone is bound to use it, allow an equivalent
708 IPv4 form. Allow plain addresses as well. */
715 if (strncmpic(s, US"[IPv6:", 6) == 0)
716 yield = (string_is_ip_address(s+6, NULL) == 6);
717 else if (strncmpic(s, US"[IPv4:", 6) == 0)
718 yield = (string_is_ip_address(s+6, NULL) == 4);
720 yield = (string_is_ip_address(s+1, NULL) != 0);
725 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
726 that have been configured (usually underscore - sigh). */
733 if (!isalnum(*s) && *s != '.' && *s != '-' &&
734 Ustrchr(helo_allow_chars, *s) == NULL)
744 /* Save argument if OK */
746 if (yield) sender_helo_name = string_copy_malloc(start);
754 /*************************************************
755 * Extract SMTP command option *
756 *************************************************/
758 /* This function picks the next option setting off the end of smtp_cmd_argument. It
759 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
760 things that can appear there.
763 name point this at the name
764 value point this at the data string
766 Returns: TRUE if found an option
770 extract_option(uschar **name, uschar **value)
773 uschar *v = smtp_cmd_argument + Ustrlen(smtp_cmd_argument) -1;
774 while (isspace(*v)) v--;
777 while (v > smtp_cmd_argument && *v != '=' && !isspace(*v)) v--;
778 if (*v != '=') return FALSE;
781 while(isalpha(n[-1])) n--;
783 if (n[-1] != ' ') return FALSE;
796 /*************************************************
797 * Reset for new message *
798 *************************************************/
800 /* This function is called whenever the SMTP session is reset from
801 within either of the setup functions.
803 Argument: the stacking pool storage reset point
808 smtp_reset(void *reset_point)
810 store_reset(reset_point);
811 recipients_list = NULL;
812 rcpt_count = rcpt_defer_count = rcpt_fail_count =
813 raw_recipients_count = recipients_count = recipients_list_max = 0;
814 message_linecount = 0;
816 acl_added_headers = NULL;
817 queue_only_policy = FALSE;
818 deliver_freeze = FALSE; /* Can be set by ACL */
819 freeze_tell = freeze_tell_config; /* Can be set by ACL */
820 fake_response = OK; /* Can be set by ACL */
821 #ifdef WITH_CONTENT_SCAN
822 no_mbox_unspool = FALSE; /* Can be set by ACL */
824 submission_mode = FALSE; /* Can be set by ACL */
825 suppress_local_fixups = FALSE; /* Can be set by ACL */
826 active_local_from_check = local_from_check; /* Can be set by ACL */
827 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
828 sender_address = NULL;
829 submission_name = NULL; /* Can be set by ACL */
830 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
831 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
832 sender_verified_list = NULL; /* No senders verified */
833 memset(sender_address_cache, 0, sizeof(sender_address_cache));
834 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
835 authenticated_sender = NULL;
836 #ifdef EXPERIMENTAL_BRIGHTMAIL
840 #ifdef EXPERIMENTAL_DOMAINKEYS
843 #ifdef EXPERIMENTAL_SPF
844 spf_header_comment = NULL;
847 spf_smtp_comment = NULL;
849 body_linecount = body_zerocount = 0;
851 sender_rate = sender_rate_limit = sender_rate_period = NULL;
852 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
853 /* Note that ratelimiters_conn persists across resets. */
855 /* Reset message ACL variables */
859 /* The message body variables use malloc store. They may be set if this is
860 not the first message in an SMTP session and the previous message caused them
861 to be referenced in an ACL. */
863 if (message_body != NULL)
865 store_free(message_body);
869 if (message_body_end != NULL)
871 store_free(message_body_end);
872 message_body_end = NULL;
875 /* Warning log messages are also saved in malloc store. They are saved to avoid
876 repetition in the same message, but it seems right to repeat them for different
879 while (acl_warn_logged != NULL)
881 string_item *this = acl_warn_logged;
882 acl_warn_logged = acl_warn_logged->next;
891 /*************************************************
892 * Initialize for incoming batched SMTP message *
893 *************************************************/
895 /* This function is called from smtp_setup_msg() in the case when
896 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
897 of messages in one file with SMTP commands between them. All errors must be
898 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
899 relevant. After an error on a sender, or an invalid recipient, the remainder
900 of the message is skipped. The value of received_protocol is already set.
903 Returns: > 0 message successfully started (reached DATA)
904 = 0 QUIT read or end of file reached
909 smtp_setup_batch_msg(void)
912 void *reset_point = store_get(0);
914 /* Save the line count at the start of each transaction - single commands
915 like HELO and RSET count as whole transactions. */
917 bsmtp_transaction_linecount = receive_linecount;
919 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
921 smtp_reset(reset_point); /* Reset for start of message */
923 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
924 value. The values are 2 larger than the required yield of the function. */
929 uschar *recipient = NULL;
930 int start, end, sender_domain, recipient_domain;
932 switch(smtp_read_command(FALSE))
934 /* The HELO/EHLO commands set sender_address_helo if they have
935 valid data; otherwise they are ignored, except that they do
936 a reset of the state. */
941 check_helo(smtp_cmd_argument);
945 smtp_reset(reset_point);
946 bsmtp_transaction_linecount = receive_linecount;
950 /* The MAIL FROM command requires an address as an operand. All we
951 do here is to parse it for syntactic correctness. The form "<>" is
952 a special case which converts into an empty string. The start/end
953 pointers in the original are not used further for this address, as
954 it is the canonical extracted address which is all that is kept. */
957 if (sender_address != NULL)
958 /* The function moan_smtp_batch() does not return. */
959 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
961 if (smtp_cmd_argument[0] == 0)
962 /* The function moan_smtp_batch() does not return. */
963 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
965 /* Reset to start of message */
967 smtp_reset(reset_point);
969 /* Apply SMTP rewrite */
971 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
972 rewrite_one(smtp_cmd_argument, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
973 US"", global_rewrite_rules) : smtp_cmd_argument;
975 /* Extract the address; the TRUE flag allows <> as valid */
978 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
981 if (raw_sender == NULL)
982 /* The function moan_smtp_batch() does not return. */
983 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
985 sender_address = string_copy(raw_sender);
987 /* Qualify unqualified sender addresses if permitted to do so. */
989 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
991 if (allow_unqualified_sender)
993 sender_address = rewrite_address_qualify(sender_address, FALSE);
994 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
995 "and rewritten\n", raw_sender);
997 /* The function moan_smtp_batch() does not return. */
998 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1004 /* The RCPT TO command requires an address as an operand. All we do
1005 here is to parse it for syntactic correctness. There may be any number
1006 of RCPT TO commands, specifying multiple senders. We build them all into
1007 a data structure that is in argc/argv format. The start/end values
1008 given by parse_extract_address are not used, as we keep only the
1009 extracted address. */
1012 if (sender_address == NULL)
1013 /* The function moan_smtp_batch() does not return. */
1014 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1016 if (smtp_cmd_argument[0] == 0)
1017 /* The function moan_smtp_batch() does not return. */
1018 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1020 /* Check maximum number allowed */
1022 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1023 /* The function moan_smtp_batch() does not return. */
1024 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1025 recipients_max_reject? "552": "452");
1027 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1028 recipient address */
1030 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1031 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
1032 global_rewrite_rules) : smtp_cmd_argument;
1034 /* rfc821_domains = TRUE; << no longer needed */
1035 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1036 &recipient_domain, FALSE);
1037 /* rfc821_domains = FALSE; << no longer needed */
1039 if (recipient == NULL)
1040 /* The function moan_smtp_batch() does not return. */
1041 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1043 /* If the recipient address is unqualified, qualify it if permitted. Then
1044 add it to the list of recipients. */
1046 if (recipient_domain == 0)
1048 if (allow_unqualified_recipient)
1050 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1052 recipient = rewrite_address_qualify(recipient, TRUE);
1054 /* The function moan_smtp_batch() does not return. */
1055 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1058 receive_add_recipient(recipient, -1);
1062 /* The DATA command is legal only if it follows successful MAIL FROM
1063 and RCPT TO commands. This function is complete when a valid DATA
1064 command is encountered. */
1067 if (sender_address == NULL || recipients_count <= 0)
1069 /* The function moan_smtp_batch() does not return. */
1070 if (sender_address == NULL)
1071 moan_smtp_batch(smtp_cmd_buffer,
1072 "503 MAIL FROM:<sender> command must precede DATA");
1074 moan_smtp_batch(smtp_cmd_buffer,
1075 "503 RCPT TO:<recipient> must precede DATA");
1079 done = 3; /* DATA successfully achieved */
1080 message_ended = END_NOTENDED; /* Indicate in middle of message */
1085 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1092 bsmtp_transaction_linecount = receive_linecount;
1103 /* The function moan_smtp_batch() does not return. */
1104 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1109 /* The function moan_smtp_batch() does not return. */
1110 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1115 /* The function moan_smtp_batch() does not return. */
1116 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1121 return done - 2; /* Convert yield values */
1127 /*************************************************
1128 * Start an SMTP session *
1129 *************************************************/
1131 /* This function is called at the start of an SMTP session. Thereafter,
1132 smtp_setup_msg() is called to initiate each separate message. This
1133 function does host-specific testing, and outputs the banner line.
1136 Returns: FALSE if the session can not continue; something has
1137 gone wrong, or the connection to the host is blocked
1141 smtp_start_session(void)
1145 uschar *user_msg, *log_msg;
1149 /* Default values for certain variables */
1151 helo_seen = esmtp = helo_accept_junk = FALSE;
1152 count_nonmail = TRUE_UNSET;
1153 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1154 smtp_delay_mail = smtp_rlm_base;
1155 auth_advertised = FALSE;
1156 pipelining_advertised = FALSE;
1157 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1159 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1161 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1162 authentication settings from -oMaa to remain in force. */
1164 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1165 authenticated_by = NULL;
1168 tls_cipher = tls_peerdn = NULL;
1169 tls_advertised = FALSE;
1172 /* Reset ACL connection variables */
1176 /* Allow for trailing 0 in the command buffer. */
1178 smtp_cmd_buffer = (uschar *)malloc(smtp_cmd_buffer_size + 1);
1179 if (smtp_cmd_buffer == NULL)
1180 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1181 "malloc() failed for SMTP command buffer");
1183 /* For batched input, the protocol setting can be overridden from the
1184 command line by a trusted caller. */
1186 if (smtp_batched_input)
1188 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1191 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1192 reset later if any of EHLO/AUTH/STARTTLS are received. */
1196 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1198 /* Set up the buffer for inputting using direct read() calls, and arrange to
1199 call the local functions instead of the standard C ones. */
1201 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1202 if (smtp_inbuffer == NULL)
1203 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1204 receive_getc = smtp_getc;
1205 receive_ungetc = smtp_ungetc;
1206 receive_feof = smtp_feof;
1207 receive_ferror = smtp_ferror;
1208 smtp_inptr = smtp_inend = smtp_inbuffer;
1209 smtp_had_eof = smtp_had_error = 0;
1211 /* Set up the message size limit; this may be host-specific */
1213 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1214 if (expand_string_message != NULL)
1216 if (thismessage_size_limit == -1)
1217 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1218 "%s", expand_string_message);
1220 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1221 "%s", expand_string_message);
1222 smtp_closedown(US"Temporary local problem - please try later");
1226 /* When a message is input locally via the -bs or -bS options, sender_host_
1227 unknown is set unless -oMa was used to force an IP address, in which case it
1228 is checked like a real remote connection. When -bs is used from inetd, this
1229 flag is not set, causing the sending host to be checked. The code that deals
1230 with IP source routing (if configured) is never required for -bs or -bS and
1231 the flag sender_host_notsocket is used to suppress it.
1233 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1234 reserve for certain hosts and/or networks. */
1236 if (!sender_host_unknown)
1239 BOOL reserved_host = FALSE;
1241 /* Look up IP options (source routing info) on the socket if this is not an
1242 -oMa "host", and if any are found, log them and drop the connection.
1244 Linux (and others now, see below) is different to everyone else, so there
1245 has to be some conditional compilation here. Versions of Linux before 2.1.15
1246 used a structure whose name was "options". Somebody finally realized that
1247 this name was silly, and it got changed to "ip_options". I use the
1248 newer name here, but there is a fudge in the script that sets up os.h
1249 to define a macro in older Linux systems.
1251 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1252 glibc 2, which has chosen ip_opts for the structure name. This is now
1253 really a glibc thing rather than a Linux thing, so the condition name
1254 has been changed to reflect this. It is relevant also to GNU/Hurd.
1256 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1257 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1258 a special macro defined in the os.h file.
1260 Some DGUX versions on older hardware appear not to support IP options at
1261 all, so there is now a general macro which can be set to cut out this
1264 How to do this properly in IPv6 is not yet known. */
1266 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1268 #ifdef GLIBC_IP_OPTIONS
1269 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1274 #elif defined DARWIN_IP_OPTIONS
1280 if (!host_checking && !sender_host_notsocket)
1283 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1284 struct ip_options *ipopt = store_get(optlen);
1286 struct ip_opts ipoptblock;
1287 struct ip_opts *ipopt = &ipoptblock;
1288 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1290 struct ipoption ipoptblock;
1291 struct ipoption *ipopt = &ipoptblock;
1292 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1295 /* Occasional genuine failures of getsockopt() have been seen - for
1296 example, "reset by peer". Therefore, just log and give up on this
1297 call, unless the error is ENOPROTOOPT. This error is given by systems
1298 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1299 of writing. So for that error, carry on - we just can't do an IP options
1302 DEBUG(D_receive) debug_printf("checking for IP options\n");
1304 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1307 if (errno != ENOPROTOOPT)
1309 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1310 host_and_ident(FALSE), strerror(errno));
1311 smtp_printf("451 SMTP service not available\r\n");
1316 /* Deal with any IP options that are set. On the systems I have looked at,
1317 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1318 more logging data than will fit in big_buffer. Nevertheless, after somebody
1319 questioned this code, I've added in some paranoid checking. */
1321 else if (optlen > 0)
1323 uschar *p = big_buffer;
1324 uschar *pend = big_buffer + big_buffer_size;
1325 uschar *opt, *adptr;
1327 struct in_addr addr;
1330 uschar *optstart = (uschar *)(ipopt->__data);
1332 uschar *optstart = (uschar *)(ipopt->ip_opts);
1334 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1337 DEBUG(D_receive) debug_printf("IP options exist\n");
1339 Ustrcpy(p, "IP options on incoming call:");
1342 for (opt = optstart; opt != NULL &&
1343 opt < (uschar *)(ipopt) + optlen;)
1357 if (!string_format(p, pend-p, " %s [@%s",
1358 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1360 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1362 inet_ntoa(ipopt->ip_dst)))
1364 inet_ntoa(ipopt->ipopt_dst)))
1372 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1374 while (optcount-- > 0)
1376 memcpy(&addr, adptr, sizeof(addr));
1377 if (!string_format(p, pend - p - 1, "%s%s",
1378 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1384 adptr += sizeof(struct in_addr);
1393 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1396 for (i = 0; i < opt[1]; i++)
1398 sprintf(CS p, "%2.2x ", opt[i]);
1409 log_write(0, LOG_MAIN, "%s", big_buffer);
1411 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1413 log_write(0, LOG_MAIN|LOG_REJECT,
1414 "connection from %s refused (IP options)", host_and_ident(FALSE));
1416 smtp_printf("554 SMTP service not available\r\n");
1420 /* Length of options = 0 => there are no options */
1422 else DEBUG(D_receive) debug_printf("no IP options found\n");
1424 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1426 /* Set keep-alive in socket options. The option is on by default. This
1427 setting is an attempt to get rid of some hanging connections that stick in
1428 read() when the remote end (usually a dialup) goes away. */
1430 if (smtp_accept_keepalive && !sender_host_notsocket)
1431 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1433 /* If the current host matches host_lookup, set the name by doing a
1434 reverse lookup. On failure, sender_host_name will be NULL and
1435 host_lookup_failed will be TRUE. This may or may not be serious - optional
1438 if (verify_check_host(&host_lookup) == OK)
1440 (void)host_name_lookup();
1441 host_build_sender_fullhost();
1444 /* Delay this until we have the full name, if it is looked up. */
1446 set_process_info("handling incoming connection from %s",
1447 host_and_ident(FALSE));
1449 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1450 smtps port for use with older style SSL MTAs. */
1453 if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
1457 /* Test for explicit connection rejection */
1459 if (verify_check_host(&host_reject_connection) == OK)
1461 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1462 "from %s (host_reject_connection)", host_and_ident(FALSE));
1463 smtp_printf("554 SMTP service not available\r\n");
1467 /* Test with TCP Wrappers if so configured. There is a problem in that
1468 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1469 such as disks dying. In these cases, it is desirable to reject with a 4xx
1470 error instead of a 5xx error. There isn't a "right" way to detect such
1471 problems. The following kludge is used: errno is zeroed before calling
1472 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1473 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1476 #ifdef USE_TCP_WRAPPERS
1478 if (!hosts_ctl("exim",
1479 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1480 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1481 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1483 if (errno == 0 || errno == ENOENT)
1485 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1486 log_write(L_connection_reject,
1487 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1488 "(tcp wrappers)", host_and_ident(FALSE));
1489 smtp_printf("554 SMTP service not available\r\n");
1493 int save_errno = errno;
1494 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1495 "errno value %d\n", save_errno);
1496 log_write(L_connection_reject,
1497 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1498 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1499 smtp_printf("451 Temporary local problem - please try later\r\n");
1505 /* Check for reserved slots. Note that the count value doesn't include
1506 this process, as it gets upped in the parent process. */
1508 if (smtp_accept_max > 0 &&
1509 smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
1511 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1513 log_write(L_connection_reject,
1514 LOG_MAIN, "temporarily refused connection from %s: not in "
1515 "reserve list: connected=%d max=%d reserve=%d%s",
1516 host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
1517 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1518 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1519 "please try again later\r\n", smtp_active_hostname);
1522 reserved_host = TRUE;
1525 /* If a load level above which only messages from reserved hosts are
1526 accepted is set, check the load. For incoming calls via the daemon, the
1527 check is done in the superior process if there are no reserved hosts, to
1528 save a fork. In all cases, the load average will already be available
1529 in a global variable at this point. */
1531 if (smtp_load_reserve >= 0 &&
1532 load_average > smtp_load_reserve &&
1534 verify_check_host(&smtp_reserve_hosts) != OK)
1536 log_write(L_connection_reject,
1537 LOG_MAIN, "temporarily refused connection from %s: not in "
1538 "reserve list and load average = %.2f", host_and_ident(FALSE),
1539 (double)load_average/1000.0);
1540 smtp_printf("421 %s: Too much load; please try again later\r\n",
1541 smtp_active_hostname);
1545 /* Determine whether unqualified senders or recipients are permitted
1546 for this host. Unfortunately, we have to do this every time, in order to
1547 set the flags so that they can be inspected when considering qualifying
1548 addresses in the headers. For a site that permits no qualification, this
1549 won't take long, however. */
1551 allow_unqualified_sender =
1552 verify_check_host(&sender_unqualified_hosts) == OK;
1554 allow_unqualified_recipient =
1555 verify_check_host(&recipient_unqualified_hosts) == OK;
1557 /* Determine whether HELO/EHLO is required for this host. The requirement
1558 can be hard or soft. */
1560 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1562 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1564 /* Determine whether this hosts is permitted to send syntactic junk
1565 after a HELO or EHLO command. */
1567 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1570 /* For batch SMTP input we are now done. */
1572 if (smtp_batched_input) return TRUE;
1574 /* Run the ACL if it exists */
1577 if (acl_smtp_connect != NULL)
1580 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1584 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1589 /* Output the initial message for a two-way SMTP connection. It may contain
1590 newlines, which then cause a multi-line response to be given. */
1592 code = US"220"; /* Default status code */
1593 esc = US""; /* Default extended status code */
1594 esclen = 0; /* Length of esc */
1596 if (user_msg == NULL)
1598 s = expand_string(smtp_banner);
1600 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1601 "failed: %s", smtp_banner, expand_string_message);
1607 smtp_message_code(&code, &codelen, &s, NULL);
1611 esclen = codelen - 4;
1615 /* Remove any terminating newlines; might as well remove trailing space too */
1618 while (p > s && isspace(p[-1])) p--;
1621 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1622 is all contained in a single IP packet. The original code wrote out the
1623 greeting using several calls to fprint/fputc, and on busy servers this could
1624 cause it to be split over more than one packet - which caused CC:Mail to fall
1625 over when it got the second part of the greeting after sending its first
1626 command. Sigh. To try to avoid this, build the complete greeting message
1627 first, and output it in one fell swoop. This gives a better chance of it
1628 ending up as a single packet. */
1630 ss = store_get(size);
1634 do /* At least once, in case we have an empty string */
1637 uschar *linebreak = Ustrchr(p, '\n');
1638 ss = string_cat(ss, &size, &ptr, code, 3);
1639 if (linebreak == NULL)
1642 ss = string_cat(ss, &size, &ptr, US" ", 1);
1646 len = linebreak - p;
1647 ss = string_cat(ss, &size, &ptr, US"-", 1);
1649 ss = string_cat(ss, &size, &ptr, esc, esclen);
1650 ss = string_cat(ss, &size, &ptr, p, len);
1651 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1653 if (linebreak != NULL) p++;
1657 ss[ptr] = 0; /* string_cat leaves room for this */
1659 /* Before we write the banner, check that there is no input pending, unless
1660 this synchronisation check is disabled. */
1662 if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
1665 struct timeval tzero;
1669 FD_SET(fileno(smtp_in), &fds);
1670 if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
1673 int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
1676 if (rc > 150) rc = 150;
1677 smtp_inbuffer[rc] = 0;
1678 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1679 "synchronization error (input sent without waiting for greeting): "
1680 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1681 string_printing(smtp_inbuffer));
1682 smtp_printf("554 SMTP synchronization error\r\n");
1688 /* Now output the banner */
1690 smtp_printf("%s", ss);
1698 /*************************************************
1699 * Handle SMTP syntax and protocol errors *
1700 *************************************************/
1702 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1703 to do so. Then transmit the error response. The return value depends on the
1704 number of syntax and protocol errors in this SMTP session.
1707 type error type, given as a log flag bit
1708 code response code; <= 0 means don't send a response
1709 data data to reflect in the response (can be NULL)
1710 errmess the error message
1712 Returns: -1 limit of syntax/protocol errors NOT exceeded
1713 +1 limit of syntax/protocol errors IS exceeded
1715 These values fit in with the values of the "done" variable in the main
1716 processing loop in smtp_setup_msg(). */
1719 synprot_error(int type, int code, uschar *data, uschar *errmess)
1723 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1724 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1725 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1727 if (++synprot_error_count > smtp_max_synprot_errors)
1730 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1731 "syntax or protocol errors (last command was \"%s\")",
1732 host_and_ident(FALSE), smtp_cmd_buffer);
1737 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1738 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1740 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1749 /*************************************************
1750 * Log incomplete transactions *
1751 *************************************************/
1753 /* This function is called after a transaction has been aborted by RSET, QUIT,
1754 connection drops or other errors. It logs the envelope information received
1755 so far in order to preserve address verification attempts.
1757 Argument: string to indicate what aborted the transaction
1762 incomplete_transaction_log(uschar *what)
1764 if (sender_address == NULL || /* No transaction in progress */
1765 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
1768 /* Build list of recipients for logging */
1770 if (recipients_count > 0)
1773 raw_recipients = store_get(recipients_count * sizeof(uschar *));
1774 for (i = 0; i < recipients_count; i++)
1775 raw_recipients[i] = recipients_list[i].address;
1776 raw_recipients_count = recipients_count;
1779 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
1780 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
1786 /*************************************************
1787 * Send SMTP response, possibly multiline *
1788 *************************************************/
1790 /* There are, it seems, broken clients out there that cannot handle multiline
1791 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
1792 output nothing for non-final calls, and only the first line for anything else.
1795 code SMTP code, may involve extended status codes
1796 codelen length of smtp code; if > 3 there's an ESC
1797 final FALSE if the last line isn't the final line
1798 msg message text, possibly containing newlines
1804 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
1809 if (!final && no_multiline_responses) return;
1814 esclen = codelen - 4;
1819 uschar *nl = Ustrchr(msg, '\n');
1822 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
1825 else if (nl[1] == 0 || no_multiline_responses)
1827 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
1828 (int)(nl - msg), msg);
1833 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
1835 while (isspace(*msg)) msg++;
1843 /*************************************************
1844 * Parse user SMTP message *
1845 *************************************************/
1847 /* This function allows for user messages overriding the response code details
1848 by providing a suitable response code string at the start of the message
1849 user_msg. Check the message for starting with a response code and optionally an
1850 extended status code. If found, check that the first digit is valid, and if so,
1851 change the code pointer and length to use the replacement. An invalid code
1852 causes a panic log; in this case, if the log messages is the same as the user
1853 message, we must also adjust the value of the log message to show the code that
1854 is actually going to be used (the original one).
1856 This function is global because it is called from receive.c as well as within
1860 code SMTP code, may involve extended status codes
1861 codelen length of smtp code; if > 3 there's an ESC
1863 log_msg optional log message, to be adjusted with the new SMTP code
1869 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
1874 if (msg == NULL || *msg == NULL) return;
1876 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
1877 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
1880 if ((*msg)[0] != (*code)[0])
1882 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
1883 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
1884 if (log_msg != NULL && *log_msg == *msg)
1885 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
1890 *codelen = ovector[1]; /* Includes final space */
1892 *msg += ovector[1]; /* Chop the code off the message */
1899 /*************************************************
1900 * Handle an ACL failure *
1901 *************************************************/
1903 /* This function is called when acl_check() fails. As well as calls from within
1904 this module, it is called from receive.c for an ACL after DATA. It sorts out
1905 logging the incident, and sets up the error response. A message containing
1906 newlines is turned into a multiline SMTP response, but for logging, only the
1909 There's a table of default permanent failure response codes to use in
1910 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
1911 defaults disabled in Exim. However, discussion in connection with RFC 821bis
1912 (aka RFC 2821) has concluded that the response should be 252 in the disabled
1913 state, because there are broken clients that try VRFY before RCPT. A 5xx
1914 response should be given only when the address is positively known to be
1915 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
1918 From Exim 4.63, it is possible to override the response code details by
1919 providing a suitable response code string at the start of the message provided
1920 in user_msg. The code's first digit is checked for validity.
1923 where where the ACL was called from
1925 user_msg a message that can be included in an SMTP response
1926 log_msg a message for logging
1928 Returns: 0 in most cases
1929 2 if the failure code was FAIL_DROP, in which case the
1930 SMTP connection should be dropped (this value fits with the
1931 "done" variable in smtp_setup_msg() below)
1935 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
1937 BOOL drop = rc == FAIL_DROP;
1941 uschar *sender_info = US"";
1943 #ifdef WITH_CONTENT_SCAN
1944 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
1946 (where == ACL_WHERE_PREDATA)? US"DATA" :
1947 (where == ACL_WHERE_DATA)? US"after DATA" :
1948 (smtp_cmd_argument == NULL)?
1949 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
1950 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_argument);
1952 if (drop) rc = FAIL;
1954 /* Set the default SMTP code, and allow a user message to change it. */
1956 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
1957 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
1959 /* We used to have sender_address here; however, there was a bug that was not
1960 updating sender_address after a rewrite during a verify. When this bug was
1961 fixed, sender_address at this point became the rewritten address. I'm not sure
1962 this is what should be logged, so I've changed to logging the unrewritten
1963 address to retain backward compatibility. */
1965 #ifndef WITH_CONTENT_SCAN
1966 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
1968 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
1971 sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
1972 sender_address_unrewritten : sender_address);
1975 /* If there's been a sender verification failure with a specific message, and
1976 we have not sent a response about it yet, do so now, as a preliminary line for
1977 failures, but not defers. However, always log it for defer, and log it for fail
1978 unless the sender_verify_fail log selector has been turned off. */
1980 if (sender_verified_failed != NULL &&
1981 !testflag(sender_verified_failed, af_sverify_told))
1983 setflag(sender_verified_failed, af_sverify_told);
1985 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
1986 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
1987 host_and_ident(TRUE),
1988 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
1989 sender_verified_failed->address,
1990 (sender_verified_failed->message == NULL)? US"" :
1991 string_sprintf(": %s", sender_verified_failed->message));
1993 if (rc == FAIL && sender_verified_failed->user_message != NULL)
1994 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
1995 testflag(sender_verified_failed, af_verify_pmfail)?
1996 "Postmaster verification failed while checking <%s>\n%s\n"
1997 "Several RFCs state that you are required to have a postmaster\n"
1998 "mailbox for each mail domain. This host does not accept mail\n"
1999 "from domains whose servers reject the postmaster address."
2001 testflag(sender_verified_failed, af_verify_nsfail)?
2002 "Callback setup failed while verifying <%s>\n%s\n"
2003 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2004 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2005 "RFC requirements, and stops you from receiving standard bounce\n"
2006 "messages. This host does not accept mail from domains whose servers\n"
2009 "Verification failed for <%s>\n%s",
2010 sender_verified_failed->address,
2011 sender_verified_failed->user_message));
2014 /* Sort out text for logging */
2016 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2017 lognl = Ustrchr(log_msg, '\n');
2018 if (lognl != NULL) *lognl = 0;
2020 /* Send permanent failure response to the command, but the code used isn't
2021 always a 5xx one - see comments at the start of this function. If the original
2022 rc was FAIL_DROP we drop the connection and yield 2. */
2024 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2025 US"Administrative prohibition" : user_msg);
2027 /* Send temporary failure response to the command. Don't give any details,
2028 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2029 verb, and for a header verify when smtp_return_error_details is set.
2031 This conditional logic is all somewhat of a mess because of the odd
2032 interactions between temp_details and return_error_details. One day it should
2033 be re-implemented in a tidier fashion. */
2037 if (acl_temp_details && user_msg != NULL)
2039 if (smtp_return_error_details &&
2040 sender_verified_failed != NULL &&
2041 sender_verified_failed->message != NULL)
2043 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2045 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2048 smtp_respond(smtp_code, codelen, TRUE,
2049 US"Temporary local problem - please try later");
2052 /* Log the incident to the logs that are specified by log_reject_target
2053 (default main, reject). This can be empty to suppress logging of rejections. If
2054 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2055 is closing if required and return 2. */
2057 if (log_reject_target != 0)
2058 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2059 host_and_ident(TRUE),
2060 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2062 if (!drop) return 0;
2064 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2065 smtp_get_connection_info());
2072 /*************************************************
2073 * Verify HELO argument *
2074 *************************************************/
2076 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2077 matched. It is also called from ACL processing if verify = helo is used and
2078 verification was not previously tried (i.e. helo_try_verify_hosts was not
2079 matched). The result of its processing is to set helo_verified and
2080 helo_verify_failed. These variables should both be FALSE for this function to
2083 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2084 for IPv6 ::ffff: literals.
2087 Returns: TRUE if testing was completed;
2088 FALSE on a temporary failure
2092 smtp_verify_helo(void)
2096 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2099 if (sender_helo_name == NULL)
2101 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2104 /* Deal with the case of -bs without an IP address */
2106 else if (sender_host_address == NULL)
2108 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2109 helo_verified = TRUE;
2112 /* Deal with the more common case when there is a sending IP address */
2114 else if (sender_helo_name[0] == '[')
2116 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2117 Ustrlen(sender_host_address)) == 0;
2122 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2123 helo_verified = Ustrncmp(sender_helo_name + 1,
2124 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2129 { if (helo_verified) debug_printf("matched host address\n"); }
2132 /* Do a reverse lookup if one hasn't already given a positive or negative
2133 response. If that fails, or the name doesn't match, try checking with a forward
2138 if (sender_host_name == NULL && !host_lookup_failed)
2139 yield = host_name_lookup() != DEFER;
2141 /* If a host name is known, check it and all its aliases. */
2143 if (sender_host_name != NULL)
2145 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2149 HDEBUG(D_receive) debug_printf("matched host name\n");
2153 uschar **aliases = sender_host_aliases;
2154 while (*aliases != NULL)
2156 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2157 if (helo_verified) break;
2162 debug_printf("matched alias %s\n", *(--aliases));
2167 /* Final attempt: try a forward lookup of the helo name */
2173 h.name = sender_helo_name;
2177 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2179 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2180 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2185 if (Ustrcmp(hh->address, sender_host_address) == 0)
2187 helo_verified = TRUE;
2189 debug_printf("IP address for %s matches calling address\n",
2199 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2206 /*************************************************
2207 * Send user response message *
2208 *************************************************/
2210 /* This function is passed a default response code and a user message. It calls
2211 smtp_message_code() to check and possibly modify the response code, and then
2212 calls smtp_respond() to transmit the response. I put this into a function
2213 just to avoid a lot of repetition.
2216 code the response code
2217 user_msg the user message
2223 smtp_user_msg(uschar *code, uschar *user_msg)
2226 smtp_message_code(&code, &len, &user_msg, NULL);
2227 smtp_respond(code, len, TRUE, user_msg);
2233 /*************************************************
2234 * Initialize for SMTP incoming message *
2235 *************************************************/
2237 /* This function conducts the initial dialogue at the start of an incoming SMTP
2238 message, and builds a list of recipients. However, if the incoming message
2239 is part of a batch (-bS option) a separate function is called since it would
2240 be messy having tests splattered about all over this function. This function
2241 therefore handles the case where interaction is occurring. The input and output
2242 files are set up in smtp_in and smtp_out.
2244 The global recipients_list is set to point to a vector of recipient_item
2245 blocks, whose number is given by recipients_count. This is extended by the
2246 receive_add_recipient() function. The global variable sender_address is set to
2247 the sender's address. The yield is +1 if a message has been successfully
2248 started, 0 if a QUIT command was encountered or the connection was refused from
2249 the particular host, or -1 if the connection was lost.
2253 Returns: > 0 message successfully started (reached DATA)
2254 = 0 QUIT read or end of file reached or call refused
2259 smtp_setup_msg(void)
2262 BOOL toomany = FALSE;
2263 BOOL discarded = FALSE;
2264 BOOL last_was_rej_mail = FALSE;
2265 BOOL last_was_rcpt = FALSE;
2266 void *reset_point = store_get(0);
2268 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2270 /* Reset for start of new message. We allow one RSET not to be counted as a
2271 nonmail command, for those MTAs that insist on sending it between every
2272 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2273 TLS between messages (an Exim client may do this if it has messages queued up
2274 for the host). Note: we do NOT reset AUTH at this point. */
2276 smtp_reset(reset_point);
2277 message_ended = END_NOTSTARTED;
2279 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2280 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2281 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2283 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2286 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2288 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2290 /* Batched SMTP is handled in a different function. */
2292 if (smtp_batched_input) return smtp_setup_batch_msg();
2294 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2295 value. The values are 2 larger than the required yield of the function. */
2300 uschar *etrn_command;
2301 uschar *etrn_serialize_key;
2303 uschar *log_msg, *smtp_code;
2304 uschar *user_msg = NULL;
2305 uschar *recipient = NULL;
2306 uschar *hello = NULL;
2307 uschar *set_id = NULL;
2309 BOOL was_rej_mail = FALSE;
2310 BOOL was_rcpt = FALSE;
2311 void (*oldsignal)(int);
2313 int start, end, sender_domain, recipient_domain;
2318 switch(smtp_read_command(TRUE))
2320 /* The AUTH command is not permitted to occur inside a transaction, and may
2321 occur successfully only once per connection. Actually, that isn't quite
2322 true. When TLS is started, all previous information about a connection must
2323 be discarded, so a new AUTH is permitted at that time.
2325 AUTH may only be used when it has been advertised. However, it seems that
2326 there are clients that send AUTH when it hasn't been advertised, some of
2327 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2328 So there's a get-out that allows this to happen.
2330 AUTH is initially labelled as a "nonmail command" so that one occurrence
2331 doesn't get counted. We change the label here so that multiple failing
2332 AUTHS will eventually hit the nonmail threshold. */
2335 authentication_failed = TRUE;
2336 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2338 if (!auth_advertised && !allow_auth_unadvertised)
2340 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2341 US"AUTH command used when not advertised");
2344 if (sender_host_authenticated != NULL)
2346 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2347 US"already authenticated");
2350 if (sender_address != NULL)
2352 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2353 US"not permitted in mail transaction");
2359 if (acl_smtp_auth != NULL)
2361 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2364 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2369 /* Find the name of the requested authentication mechanism. */
2371 s = smtp_cmd_argument;
2372 while ((c = *smtp_cmd_argument) != 0 && !isspace(c))
2374 if (!isalnum(c) && c != '-' && c != '_')
2376 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2377 US"invalid character in authentication mechanism name");
2380 smtp_cmd_argument++;
2383 /* If not at the end of the line, we must be at white space. Terminate the
2384 name and move the pointer on to any data that may be present. */
2386 if (*smtp_cmd_argument != 0)
2388 *smtp_cmd_argument++ = 0;
2389 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
2392 /* Search for an authentication mechanism which is configured for use
2393 as a server and which has been advertised (unless, sigh, allow_auth_
2394 unadvertised is set). */
2396 for (au = auths; au != NULL; au = au->next)
2398 if (strcmpic(s, au->public_name) == 0 && au->server &&
2399 (au->advertised || allow_auth_unadvertised)) break;
2404 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2405 string_sprintf("%s authentication mechanism not supported", s));
2409 /* Run the checking code, passing the remainder of the command line as
2410 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2411 it as the only set numerical variable. The authenticator may set $auth<n>
2412 and also set other numeric variables. The $auth<n> variables are preferred
2413 nowadays; the numerical variables remain for backwards compatibility.
2415 Afterwards, have a go at expanding the set_id string, even if
2416 authentication failed - for bad passwords it can be useful to log the
2417 userid. On success, require set_id to expand and exist, and put it in
2418 authenticated_id. Save this in permanent store, as the working store gets
2419 reset at HELO, RSET, etc. */
2421 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2423 expand_nlength[0] = 0; /* $0 contains nothing */
2425 c = (au->info->servercode)(au, smtp_cmd_argument);
2426 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2427 expand_nmax = -1; /* Reset numeric variables */
2428 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2430 /* The value of authenticated_id is stored in the spool file and printed in
2431 log lines. It must not contain binary zeros or newline characters. In
2432 normal use, it never will, but when playing around or testing, this error
2433 can (did) happen. To guard against this, ensure that the id contains only
2434 printing characters. */
2436 if (set_id != NULL) set_id = string_printing(set_id);
2438 /* For the non-OK cases, set up additional logging data if set_id
2443 if (set_id != NULL && *set_id != 0)
2444 set_id = string_sprintf(" (set_id=%s)", set_id);
2448 /* Switch on the result */
2453 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2455 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2456 sender_host_authenticated = au->name;
2457 authentication_failed = FALSE;
2459 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2460 ((sender_host_address != NULL)? pnlocal : 0);
2461 s = ss = US"235 Authentication succeeded";
2462 authenticated_by = au;
2466 /* Authentication succeeded, but we failed to expand the set_id string.
2467 Treat this as a temporary error. */
2469 auth_defer_msg = expand_string_message;
2473 s = string_sprintf("435 Unable to authenticate at present%s",
2474 auth_defer_user_msg);
2475 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2476 set_id, auth_defer_msg);
2480 s = ss = US"501 Invalid base64 data";
2484 s = ss = US"501 Authentication cancelled";
2488 s = ss = US"553 Initial data not expected";
2492 s = US"535 Incorrect authentication data";
2493 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2497 s = US"435 Internal error";
2498 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2499 "check", set_id, c);
2503 smtp_printf("%s\r\n", s);
2505 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2506 au->name, host_and_ident(FALSE), ss);
2508 break; /* AUTH_CMD */
2510 /* The HELO/EHLO commands are permitted to appear in the middle of a
2511 session as well as at the beginning. They have the effect of a reset in
2512 addition to their other functions. Their absence at the start cannot be
2513 taken to be an error.
2517 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2518 or 502 failure replies MUST be returned as appropriate. The SMTP
2519 server MUST stay in the same state after transmitting these replies
2520 that it was in before the EHLO was received.
2522 Therefore, we do not do the reset until after checking the command for
2523 acceptability. This change was made for Exim release 4.11. Previously
2524 it did the reset first. */
2535 HELO_EHLO: /* Common code for HELO and EHLO */
2536 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2537 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2539 /* Reject the HELO if its argument was invalid or non-existent. A
2540 successful check causes the argument to be saved in malloc store. */
2542 if (!check_helo(smtp_cmd_argument))
2544 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2546 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2547 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2548 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2549 string_printing(smtp_cmd_argument));
2551 if (++synprot_error_count > smtp_max_synprot_errors)
2553 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2554 "syntax or protocol errors (last command was \"%s\")",
2555 host_and_ident(FALSE), smtp_cmd_buffer);
2562 /* If sender_host_unknown is true, we have got here via the -bs interface,
2563 not called from inetd. Otherwise, we are running an IP connection and the
2564 host address will be set. If the helo name is the primary name of this
2565 host and we haven't done a reverse lookup, force one now. If helo_required
2566 is set, ensure that the HELO name matches the actual host. If helo_verify
2567 is set, do the same check, but softly. */
2569 if (!sender_host_unknown)
2571 BOOL old_helo_verified = helo_verified;
2572 uschar *p = smtp_cmd_argument;
2574 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2577 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2578 because otherwise the log can be confusing. */
2580 if (sender_host_name == NULL &&
2581 (deliver_domain = sender_helo_name, /* set $domain */
2582 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2583 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2584 (void)host_name_lookup();
2586 /* Rebuild the fullhost info to include the HELO name (and the real name
2587 if it was looked up.) */
2589 host_build_sender_fullhost(); /* Rebuild */
2590 set_process_info("handling%s incoming connection from %s",
2591 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2593 /* Verify if configured. This doesn't give much security, but it does
2594 make some people happy to be able to do it. If helo_required is set,
2595 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2596 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2597 now obsolescent, since the verification can now be requested selectively
2600 helo_verified = helo_verify_failed = FALSE;
2601 if (helo_required || helo_verify)
2603 BOOL tempfail = !smtp_verify_helo();
2608 smtp_printf("%d %s argument does not match calling host\r\n",
2609 tempfail? 451 : 550, hello);
2610 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2611 tempfail? "temporarily " : "",
2612 hello, sender_helo_name, host_and_ident(FALSE));
2613 helo_verified = old_helo_verified;
2614 break; /* End of HELO/EHLO processing */
2616 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2617 "helo_try_verify_hosts\n", hello);
2622 #ifdef EXPERIMENTAL_SPF
2623 /* set up SPF context */
2624 spf_init(sender_helo_name, sender_host_address);
2627 /* Apply an ACL check if one is defined */
2629 if (acl_smtp_helo != NULL)
2631 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2634 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2635 sender_helo_name = NULL;
2636 host_build_sender_fullhost(); /* Rebuild */
2641 /* Generate an OK reply. The default string includes the ident if present,
2642 and also the IP address if present. Reflecting back the ident is intended
2643 as a deterrent to mail forgers. For maximum efficiency, and also because
2644 some broken systems expect each response to be in a single packet, arrange
2645 that the entire reply is sent in one write(). */
2647 auth_advertised = FALSE;
2648 pipelining_advertised = FALSE;
2650 tls_advertised = FALSE;
2653 smtp_code = US"250"; /* Default response code */
2654 if (user_msg == NULL)
2656 s = string_sprintf("%.3s %s Hello %s%s%s",
2658 smtp_active_hostname,
2659 (sender_ident == NULL)? US"" : sender_ident,
2660 (sender_ident == NULL)? US"" : US" at ",
2661 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
2666 if (sender_host_address != NULL)
2668 s = string_cat(s, &size, &ptr, US" [", 2);
2669 s = string_cat(s, &size, &ptr, sender_host_address,
2670 Ustrlen(sender_host_address));
2671 s = string_cat(s, &size, &ptr, US"]", 1);
2675 /* A user-supplied EHLO greeting may not contain more than one line */
2681 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
2682 s = string_sprintf("%.*s %s", codelen, smtp_code, user_msg);
2683 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
2685 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
2686 "newlines: message truncated: %s", string_printing(s));
2693 s = string_cat(s, &size, &ptr, US"\r\n", 2);
2695 /* If we received EHLO, we must create a multiline response which includes
2696 the functions supported. */
2702 /* I'm not entirely happy with this, as an MTA is supposed to check
2703 that it has enough room to accept a message of maximum size before
2704 it sends this. However, there seems little point in not sending it.
2705 The actual size check happens later at MAIL FROM time. By postponing it
2706 till then, VRFY and EXPN can be used after EHLO when space is short. */
2708 if (thismessage_size_limit > 0)
2710 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
2711 thismessage_size_limit);
2712 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
2716 s = string_cat(s, &size, &ptr, smtp_code, 3);
2717 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
2720 /* Exim does not do protocol conversion or data conversion. It is 8-bit
2721 clean; if it has an 8-bit character in its hand, it just sends it. It
2722 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
2723 However, some users want this option simply in order to stop MUAs
2724 mangling messages that contain top-bit-set characters. It is therefore
2725 provided as an option. */
2727 if (accept_8bitmime)
2729 s = string_cat(s, &size, &ptr, smtp_code, 3);
2730 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
2733 /* Advertise ETRN if there's an ACL checking whether a host is
2734 permitted to issue it; a check is made when any host actually tries. */
2736 if (acl_smtp_etrn != NULL)
2738 s = string_cat(s, &size, &ptr, smtp_code, 3);
2739 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
2742 /* Advertise EXPN if there's an ACL checking whether a host is
2743 permitted to issue it; a check is made when any host actually tries. */
2745 if (acl_smtp_expn != NULL)
2747 s = string_cat(s, &size, &ptr, smtp_code, 3);
2748 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
2751 /* Exim is quite happy with pipelining, so let the other end know that
2752 it is safe to use it, unless advertising is disabled. */
2754 if (verify_check_host(&pipelining_advertise_hosts) == OK)
2756 s = string_cat(s, &size, &ptr, smtp_code, 3);
2757 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
2758 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
2759 pipelining_advertised = TRUE;
2762 /* If any server authentication mechanisms are configured, advertise
2763 them if the current host is in auth_advertise_hosts. The problem with
2764 advertising always is that some clients then require users to
2765 authenticate (and aren't configurable otherwise) even though it may not
2766 be necessary (e.g. if the host is in host_accept_relay).
2768 RFC 2222 states that SASL mechanism names contain only upper case
2769 letters, so output the names in upper case, though we actually recognize
2770 them in either case in the AUTH command. */
2774 if (verify_check_host(&auth_advertise_hosts) == OK)
2778 for (au = auths; au != NULL; au = au->next)
2780 if (au->server && (au->advertise_condition == NULL ||
2781 expand_check_condition(au->advertise_condition, au->name,
2782 US"authenticator")))
2787 s = string_cat(s, &size, &ptr, smtp_code, 3);
2788 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
2790 auth_advertised = TRUE;
2793 s = string_cat(s, &size, &ptr, US" ", 1);
2794 s = string_cat(s, &size, &ptr, au->public_name,
2795 Ustrlen(au->public_name));
2796 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
2797 au->advertised = TRUE;
2799 else au->advertised = FALSE;
2801 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
2805 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
2806 if it has been included in the binary, and the host matches
2807 tls_advertise_hosts. We must *not* advertise if we are already in a
2808 secure connection. */
2811 if (tls_active < 0 &&
2812 verify_check_host(&tls_advertise_hosts) != FAIL)
2814 s = string_cat(s, &size, &ptr, smtp_code, 3);
2815 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
2816 tls_advertised = TRUE;
2820 /* Finish off the multiline reply with one that is always available. */
2822 s = string_cat(s, &size, &ptr, smtp_code, 3);
2823 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
2826 /* Terminate the string (for debug), write it, and note that HELO/EHLO
2832 if (tls_active >= 0) (void)tls_write(s, ptr); else
2835 (void)fwrite(s, 1, ptr, smtp_out);
2839 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
2840 memmove(cr, cr + 1, (ptr--) - (cr - s));
2841 debug_printf("SMTP>> %s", s);
2845 /* Reset the protocol and the state, abandoning any previous message. */
2847 received_protocol = (esmtp?
2849 ((sender_host_authenticated != NULL)? pauthed : 0) +
2850 ((tls_active >= 0)? pcrpted : 0)]
2852 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
2854 ((sender_host_address != NULL)? pnlocal : 0);
2856 smtp_reset(reset_point);
2858 break; /* HELO/EHLO */
2861 /* The MAIL command requires an address as an operand. All we do
2862 here is to parse it for syntactic correctness. The form "<>" is
2863 a special case which converts into an empty string. The start/end
2864 pointers in the original are not used further for this address, as
2865 it is the canonical extracted address which is all that is kept. */
2868 smtp_mailcmd_count++; /* Count for limit and ratelimit */
2869 was_rej_mail = TRUE; /* Reset if accepted */
2871 if (helo_required && !helo_seen)
2873 smtp_printf("503 HELO or EHLO required\r\n");
2874 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
2875 "HELO/EHLO given", host_and_ident(FALSE));
2879 if (sender_address != NULL)
2881 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2882 US"sender already given");
2886 if (smtp_cmd_argument[0] == 0)
2888 done = synprot_error(L_smtp_protocol_error, 501, NULL,
2889 US"MAIL must have an address operand");
2893 /* Check to see if the limit for messages per connection would be
2894 exceeded by accepting further messages. */
2896 if (smtp_accept_max_per_connection > 0 &&
2897 smtp_mailcmd_count > smtp_accept_max_per_connection)
2899 smtp_printf("421 too many messages in this connection\r\n");
2900 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
2901 "messages in one connection", host_and_ident(TRUE));
2905 /* Reset for start of message - even if this is going to fail, we
2906 obviously need to throw away any previous data. */
2908 smtp_reset(reset_point);
2910 sender_data = recipient_data = NULL;
2912 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
2916 uschar *name, *value, *end;
2917 unsigned long int size;
2919 if (!extract_option(&name, &value)) break;
2921 /* Handle SIZE= by reading the value. We don't do the check till later,
2922 in order to be able to log the sender address on failure. */
2924 if (strcmpic(name, US"SIZE") == 0 &&
2925 ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
2927 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
2929 message_size = (int)size;
2932 /* If this session was initiated with EHLO and accept_8bitmime is set,
2933 Exim will have indicated that it supports the BODY=8BITMIME option. In
2934 fact, it does not support this according to the RFCs, in that it does not
2935 take any special action for forwarding messages containing 8-bit
2936 characters. That is why accept_8bitmime is not the default setting, but
2937 some sites want the action that is provided. We recognize both "8BITMIME"
2938 and "7BIT" as body types, but take no action. */
2940 else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
2941 (strcmpic(value, US"8BITMIME") == 0 ||
2942 strcmpic(value, US"7BIT") == 0)) {}
2944 /* Handle the AUTH extension. If the value given is not "<>" and either
2945 the ACL says "yes" or there is no ACL but the sending host is
2946 authenticated, we set it up as the authenticated sender. However, if the
2947 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
2948 the condition is met. The value of AUTH is an xtext, which means that +,
2949 = and cntrl chars are coded in hex; however "<>" is unaffected by this
2952 else if (strcmpic(name, US"AUTH") == 0)
2954 if (Ustrcmp(value, "<>") != 0)
2959 if (auth_xtextdecode(value, &authenticated_sender) < 0)
2961 /* Put back terminator overrides for error message */
2964 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2965 US"invalid data for AUTH");
2969 if (acl_smtp_mailauth == NULL)
2971 ignore_msg = US"client not authenticated";
2972 rc = (sender_host_authenticated != NULL)? OK : FAIL;
2976 ignore_msg = US"rejected by ACL";
2977 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
2978 &user_msg, &log_msg);
2984 if (authenticated_by == NULL ||
2985 authenticated_by->mail_auth_condition == NULL ||
2986 expand_check_condition(authenticated_by->mail_auth_condition,
2987 authenticated_by->name, US"authenticator"))
2988 break; /* Accept the AUTH */
2990 ignore_msg = US"server_mail_auth_condition failed";
2991 if (authenticated_id != NULL)
2992 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
2993 ignore_msg, authenticated_id);
2998 authenticated_sender = NULL;
2999 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3000 value, host_and_ident(TRUE), ignore_msg);
3003 /* Should only get DEFER or ERROR here. Put back terminator
3004 overrides for error message */
3009 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3016 /* Unknown option. Stick back the terminator characters and break
3017 the loop. An error for a malformed address will occur. */
3027 /* If we have passed the threshold for rate limiting, apply the current
3028 delay, and update it for next time, provided this is a limited host. */
3030 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3031 verify_check_host(&smtp_ratelimit_hosts) == OK)
3033 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3034 smtp_delay_mail/1000.0);
3035 millisleep((int)smtp_delay_mail);
3036 smtp_delay_mail *= smtp_rlm_factor;
3037 if (smtp_delay_mail > (double)smtp_rlm_limit)
3038 smtp_delay_mail = (double)smtp_rlm_limit;
3041 /* Now extract the address, first applying any SMTP-time rewriting. The
3042 TRUE flag allows "<>" as a sender address. */
3044 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3045 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
3046 global_rewrite_rules) : smtp_cmd_argument;
3048 /* rfc821_domains = TRUE; << no longer needed */
3050 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3052 /* rfc821_domains = FALSE; << no longer needed */
3054 if (raw_sender == NULL)
3056 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
3060 sender_address = raw_sender;
3062 /* If there is a configured size limit for mail, check that this message
3063 doesn't exceed it. The check is postponed to this point so that the sender
3066 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3068 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3069 log_write(L_size_reject,
3070 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3071 "message too big: size%s=%d max=%d",
3073 host_and_ident(TRUE),
3074 (message_size == INT_MAX)? ">" : "",
3076 thismessage_size_limit);
3077 sender_address = NULL;
3081 /* Check there is enough space on the disk unless configured not to.
3082 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3083 plus the current message - i.e. we accept the message only if it won't
3084 reduce the space below the threshold. Add 5000 to the size to allow for
3085 overheads such as the Received: line and storing of recipients, etc.
3086 By putting the check here, even when SIZE is not given, it allow VRFY
3087 and EXPN etc. to be used when space is short. */
3089 if (!receive_check_fs(
3090 (smtp_check_spool_space && message_size >= 0)?
3091 message_size + 5000 : 0))
3093 smtp_printf("452 Space shortage, please try later\r\n");
3094 sender_address = NULL;
3098 /* If sender_address is unqualified, reject it, unless this is a locally
3099 generated message, or the sending host or net is permitted to send
3100 unqualified addresses - typically local machines behaving as MUAs -
3101 in which case just qualify the address. The flag is set above at the start
3102 of the SMTP connection. */
3104 if (sender_domain == 0 && sender_address[0] != 0)
3106 if (allow_unqualified_sender)
3108 sender_domain = Ustrlen(sender_address) + 1;
3109 sender_address = rewrite_address_qualify(sender_address, FALSE);
3110 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3115 smtp_printf("501 %s: sender address must contain a domain\r\n",
3117 log_write(L_smtp_syntax_error,
3118 LOG_MAIN|LOG_REJECT,
3119 "unqualified sender rejected: <%s> %s%s",
3121 host_and_ident(TRUE),
3123 sender_address = NULL;
3128 /* Apply an ACL check if one is defined, before responding */
3130 rc = (acl_smtp_mail == NULL)? OK :
3131 acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3133 if (rc == OK || rc == DISCARD)
3135 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3136 else smtp_user_msg(US"250", user_msg);
3137 smtp_delay_rcpt = smtp_rlr_base;
3138 recipients_discarded = (rc == DISCARD);
3139 was_rej_mail = FALSE;
3143 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3144 sender_address = NULL;
3149 /* The RCPT command requires an address as an operand. All we do
3150 here is to parse it for syntactic correctness. There may be any number
3151 of RCPT commands, specifying multiple senders. We build them all into
3152 a data structure that is in argc/argv format. The start/end values
3153 given by parse_extract_address are not used, as we keep only the
3154 extracted address. */
3160 /* There must be a sender address; if the sender was rejected and
3161 pipelining was advertised, we assume the client was pipelining, and do not
3162 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3163 get the same treatment. */
3165 if (sender_address == NULL)
3167 if (pipelining_advertised && last_was_rej_mail)
3169 smtp_printf("503 sender not yet given\r\n");
3170 was_rej_mail = TRUE;
3174 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3175 US"sender not yet given");
3176 was_rcpt = FALSE; /* Not a valid RCPT */
3182 /* Check for an operand */
3184 if (smtp_cmd_argument[0] == 0)
3186 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3187 US"RCPT must have an address operand");
3192 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3193 as a recipient address */
3195 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3196 rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
3197 global_rewrite_rules) : smtp_cmd_argument;
3199 /* rfc821_domains = TRUE; << no longer needed */
3200 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3201 &recipient_domain, FALSE);
3202 /* rfc821_domains = FALSE; << no longer needed */
3204 if (recipient == NULL)
3206 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
3211 /* If the recipient address is unqualified, reject it, unless this is a
3212 locally generated message. However, unqualified addresses are permitted
3213 from a configured list of hosts and nets - typically when behaving as
3214 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3215 really. The flag is set at the start of the SMTP connection.
3217 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3218 assumed this meant "reserved local part", but the revision of RFC 821 and
3219 friends now makes it absolutely clear that it means *mailbox*. Consequently
3220 we must always qualify this address, regardless. */
3222 if (recipient_domain == 0)
3224 if (allow_unqualified_recipient ||
3225 strcmpic(recipient, US"postmaster") == 0)
3227 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3229 recipient_domain = Ustrlen(recipient) + 1;
3230 recipient = rewrite_address_qualify(recipient, TRUE);
3235 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3237 log_write(L_smtp_syntax_error,
3238 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3239 "<%s> %s%s", recipient, host_and_ident(TRUE),
3245 /* Check maximum allowed */
3247 if (rcpt_count > recipients_max && recipients_max > 0)
3249 if (recipients_max_reject)
3252 smtp_printf("552 too many recipients\r\n");
3254 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3255 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3260 smtp_printf("452 too many recipients\r\n");
3262 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3263 "temporarily rejected: sender=<%s> %s", sender_address,
3264 host_and_ident(TRUE));
3271 /* If we have passed the threshold for rate limiting, apply the current
3272 delay, and update it for next time, provided this is a limited host. */
3274 if (rcpt_count > smtp_rlr_threshold &&
3275 verify_check_host(&smtp_ratelimit_hosts) == OK)
3277 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3278 smtp_delay_rcpt/1000.0);
3279 millisleep((int)smtp_delay_rcpt);
3280 smtp_delay_rcpt *= smtp_rlr_factor;
3281 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3282 smtp_delay_rcpt = (double)smtp_rlr_limit;
3285 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3286 for them. Otherwise, check the access control list for this recipient. */
3288 rc = recipients_discarded? DISCARD :
3289 acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
3291 /* The ACL was happy */
3295 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3296 else smtp_user_msg(US"250", user_msg);
3297 receive_add_recipient(recipient, -1);
3300 /* The recipient was discarded */
3302 else if (rc == DISCARD)
3304 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3305 else smtp_user_msg(US"250", user_msg);
3308 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3309 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3310 (sender_address_unrewritten != NULL)?
3311 sender_address_unrewritten : sender_address,
3312 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3313 (log_msg == NULL)? US"" : US": ",
3314 (log_msg == NULL)? US"" : log_msg);
3317 /* Either the ACL failed the address, or it was deferred. */
3321 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3322 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3327 /* The DATA command is legal only if it follows successful MAIL FROM
3328 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3329 not counted as a protocol error if it follows RCPT (which must have been
3330 rejected if there are no recipients.) This function is complete when a
3331 valid DATA command is encountered.
3333 Note concerning the code used: RFC 2821 says this:
3335 - If there was no MAIL, or no RCPT, command, or all such commands
3336 were rejected, the server MAY return a "command out of sequence"
3337 (503) or "no valid recipients" (554) reply in response to the
3340 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3341 because it is the same whether pipelining is in use or not. */
3344 if (!discarded && recipients_count <= 0)
3346 if (pipelining_advertised && last_was_rcpt)
3347 smtp_printf("503 valid RCPT command must precede DATA\r\n");
3349 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3350 US"valid RCPT command must precede DATA");
3354 if (toomany && recipients_max_reject)
3356 sender_address = NULL; /* This will allow a new MAIL without RSET */
3357 sender_address_unrewritten = NULL;
3358 smtp_printf("554 Too many recipients\r\n");
3362 if (acl_smtp_predata == NULL) rc = OK; else
3364 enable_dollar_recipients = TRUE;
3365 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3367 enable_dollar_recipients = FALSE;
3372 if (user_msg == NULL)
3373 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3374 else smtp_user_msg(US"354", user_msg);
3376 message_ended = END_NOTENDED; /* Indicate in middle of data */
3379 /* Either the ACL failed the address, or it was deferred. */
3382 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3388 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3390 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3396 /* rfc821_domains = TRUE; << no longer needed */
3397 address = parse_extract_address(smtp_cmd_argument, &errmess, &start, &end,
3398 &recipient_domain, FALSE);
3399 /* rfc821_domains = FALSE; << no longer needed */
3401 if (address == NULL)
3402 s = string_sprintf("501 %s", errmess);
3405 address_item *addr = deliver_make_addr(address, FALSE);
3406 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3407 -1, -1, NULL, NULL, NULL))
3410 s = string_sprintf("250 <%s> is deliverable", address);
3414 s = (addr->user_message != NULL)?
3415 string_sprintf("451 <%s> %s", address, addr->user_message) :
3416 string_sprintf("451 Cannot resolve <%s> at this time", address);
3420 s = (addr->user_message != NULL)?
3421 string_sprintf("550 <%s> %s", address, addr->user_message) :
3422 string_sprintf("550 <%s> is not deliverable", address);
3423 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3424 smtp_cmd_argument, host_and_ident(TRUE));
3429 smtp_printf("%s\r\n", s);
3435 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3437 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3440 BOOL save_log_testing_mode = log_testing_mode;
3441 address_test_mode = log_testing_mode = TRUE;
3442 (void) verify_address(deliver_make_addr(smtp_cmd_argument, FALSE),
3443 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3445 address_test_mode = FALSE;
3446 log_testing_mode = save_log_testing_mode; /* true for -bh */
3454 if (!tls_advertised)
3456 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3457 US"STARTTLS command used when not advertised");
3461 /* Apply an ACL check if one is defined */
3463 if (acl_smtp_starttls != NULL)
3465 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3469 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3474 /* RFC 2487 is not clear on when this command may be sent, though it
3475 does state that all information previously obtained from the client
3476 must be discarded if a TLS session is started. It seems reasonble to
3477 do an implied RSET when STARTTLS is received. */
3479 incomplete_transaction_log(US"STARTTLS");
3480 smtp_reset(reset_point);
3482 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3484 /* Attempt to start up a TLS session, and if successful, discard all
3485 knowledge that was obtained previously. At least, that's what the RFC says,
3486 and that's what happens by default. However, in order to work round YAEB,
3487 there is an option to remember the esmtp state. Sigh.
3489 We must allow for an extra EHLO command and an extra AUTH command after
3490 STARTTLS that don't add to the nonmail command count. */
3492 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3494 if (!tls_remember_esmtp)
3495 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3496 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3497 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3498 if (sender_helo_name != NULL)
3500 store_free(sender_helo_name);
3501 sender_helo_name = NULL;
3502 host_build_sender_fullhost(); /* Rebuild */
3503 set_process_info("handling incoming TLS connection from %s",
3504 host_and_ident(FALSE));
3506 received_protocol = (esmtp?
3507 protocols[pextend + pcrpted +
3508 ((sender_host_authenticated != NULL)? pauthed : 0)]
3510 protocols[pnormal + pcrpted])
3512 ((sender_host_address != NULL)? pnlocal : 0);
3514 sender_host_authenticated = NULL;
3515 authenticated_id = NULL;
3516 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3517 DEBUG(D_tls) debug_printf("TLS active\n");
3518 break; /* Successful STARTTLS */
3521 /* Some local configuration problem was discovered before actually trying
3522 to do a TLS handshake; give a temporary error. */
3524 else if (rc == DEFER)
3526 smtp_printf("454 TLS currently unavailable\r\n");
3530 /* Hard failure. Reject everything except QUIT or closed connection. One
3531 cause for failure is a nested STARTTLS, in which case tls_active remains
3532 set, but we must still reject all incoming commands. */
3534 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3537 switch(smtp_read_command(FALSE))
3540 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3541 smtp_get_connection_info());
3546 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3547 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3548 smtp_get_connection_info());
3553 smtp_printf("554 Security failure\r\n");
3562 /* The ACL for QUIT is provided for gathering statistical information or
3563 similar; it does not affect the response code, but it can supply a custom
3567 incomplete_transaction_log(US"QUIT");
3569 if (acl_smtp_quit != NULL)
3571 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit,&user_msg,&log_msg);
3573 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3577 if (user_msg == NULL)
3578 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3580 smtp_respond(US"221", 3, TRUE, user_msg);
3587 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3588 smtp_get_connection_info());
3593 incomplete_transaction_log(US"RSET");
3594 smtp_reset(reset_point);
3596 smtp_printf("250 Reset OK\r\n");
3597 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3602 smtp_printf("250 OK\r\n");
3606 /* Show ETRN/EXPN/VRFY if there's
3607 an ACL for checking hosts; if actually used, a check will be done for
3611 smtp_printf("214-Commands supported:\r\n");
3615 Ustrcat(buffer, " AUTH");
3617 Ustrcat(buffer, " STARTTLS");
3619 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
3620 Ustrcat(buffer, " NOOP QUIT RSET HELP");
3621 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
3622 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
3623 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
3624 smtp_printf("214%s\r\n", buffer);
3630 incomplete_transaction_log(US"connection lost");
3631 smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
3633 /* Don't log by default unless in the middle of a message, as some mailers
3634 just drop the call rather than sending QUIT, and it clutters up the logs.
3637 if (sender_address != NULL || recipients_count > 0)
3638 log_write(L_lost_incoming_connection,
3640 "unexpected %s while reading SMTP command from %s%s",
3641 sender_host_unknown? "EOF" : "disconnection",
3642 host_and_ident(FALSE), smtp_read_error);
3644 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
3645 smtp_get_connection_info(), smtp_read_error);
3652 if (sender_address != NULL)
3654 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3655 US"ETRN is not permitted inside a transaction");
3659 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
3660 host_and_ident(FALSE));
3662 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
3665 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
3669 /* Compute the serialization key for this command. */
3671 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_argument);
3673 /* If a command has been specified for running as a result of ETRN, we
3674 permit any argument to ETRN. If not, only the # standard form is permitted,
3675 since that is strictly the only kind of ETRN that can be implemented
3676 according to the RFC. */
3678 if (smtp_etrn_command != NULL)
3682 etrn_command = smtp_etrn_command;
3683 deliver_domain = smtp_cmd_argument;
3684 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
3685 US"ETRN processing", &error);
3686 deliver_domain = NULL;
3689 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
3691 smtp_printf("458 Internal failure\r\n");
3696 /* Else set up to call Exim with the -R option. */
3700 if (*smtp_cmd_argument++ != '#')
3702 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3703 US"argument must begin with #");
3706 etrn_command = US"exim -R";
3707 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
3711 /* If we are host-testing, don't actually do anything. */
3717 debug_printf("ETRN command is: %s\n", etrn_command);
3718 debug_printf("ETRN command execution skipped\n");
3720 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3721 else smtp_user_msg(US"250", user_msg);
3726 /* If ETRN queue runs are to be serialized, check the database to
3727 ensure one isn't already running. */
3729 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
3731 smtp_printf("458 Already processing %s\r\n", smtp_cmd_argument);
3735 /* Fork a child process and run the command. We don't want to have to
3736 wait for the process at any point, so set SIGCHLD to SIG_IGN before
3737 forking. It should be set that way anyway for external incoming SMTP,
3738 but we save and restore to be tidy. If serialization is required, we
3739 actually run the command in yet another process, so we can wait for it
3740 to complete and then remove the serialization lock. */
3742 oldsignal = signal(SIGCHLD, SIG_IGN);
3744 if ((pid = fork()) == 0)
3746 smtp_input = FALSE; /* This process is not associated with the */
3747 (void)fclose(smtp_in); /* SMTP call any more. */
3748 (void)fclose(smtp_out);
3750 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
3752 /* If not serializing, do the exec right away. Otherwise, fork down
3753 into another process. */
3755 if (!smtp_etrn_serialize || (pid = fork()) == 0)
3757 DEBUG(D_exec) debug_print_argv(argv);
3758 exim_nullstd(); /* Ensure std{in,out,err} exist */
3759 execv(CS argv[0], (char *const *)argv);
3760 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
3761 etrn_command, strerror(errno));
3762 _exit(EXIT_FAILURE); /* paranoia */
3765 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
3766 is, we are in the first subprocess, after forking again. All we can do
3767 for a failing fork is to log it. Otherwise, wait for the 2nd process to
3768 complete, before removing the serialization. */
3771 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
3772 "failed: %s", strerror(errno));
3776 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
3778 (void)wait(&status);
3779 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
3783 enq_end(etrn_serialize_key);
3784 _exit(EXIT_SUCCESS);
3787 /* Back in the top level SMTP process. Check that we started a subprocess
3788 and restore the signal state. */
3792 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
3794 smtp_printf("458 Unable to fork process\r\n");
3795 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
3799 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3800 else smtp_user_msg(US"250", user_msg);
3803 signal(SIGCHLD, oldsignal);
3808 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3809 US"unexpected argument data");
3813 /* This currently happens only for NULLs, but could be extended. */
3816 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
3817 US"NULL character(s) present (shown as '?')");
3818 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
3823 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
3824 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
3825 c = smtp_inend - smtp_inptr;
3826 if (c > 150) c = 150;
3828 incomplete_transaction_log(US"sync failure");
3829 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
3830 "(next input sent too soon: pipelining was%s advertised): "
3831 "rejected \"%s\" %s next input=\"%s\"",
3832 pipelining_advertised? "" : " not",
3833 smtp_cmd_buffer, host_and_ident(TRUE),
3834 string_printing(smtp_inptr));
3835 smtp_printf("554 SMTP synchronization error\r\n");
3836 done = 1; /* Pretend eof - drops connection */
3840 case TOO_MANY_NONMAIL_CMD:
3841 incomplete_transaction_log(US"too many non-mail commands");
3842 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3843 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
3844 smtp_cmd_argument - smtp_cmd_buffer, smtp_cmd_buffer);
3845 smtp_printf("554 Too many nonmail commands\r\n");
3846 done = 1; /* Pretend eof - drops connection */
3851 if (unknown_command_count++ >= smtp_max_unknown_commands)
3853 log_write(L_smtp_syntax_error, LOG_MAIN,
3854 "SMTP syntax error in \"%s\" %s %s",
3855 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
3856 US"unrecognized command");
3857 incomplete_transaction_log(US"unrecognized command");
3858 smtp_printf("500 Too many unrecognized commands\r\n");
3860 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3861 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
3865 done = synprot_error(L_smtp_syntax_error, 500, NULL,
3866 US"unrecognized command");
3870 /* This label is used by goto's inside loops that want to break out to
3871 the end of the command-processing loop. */
3874 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
3875 last_was_rcpt = was_rcpt; /* protocol error handling */
3879 return done - 2; /* Convert yield values */
3882 /* End of smtp_in.c */