1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2012 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
14 /* Initialize for TCP wrappers if so configured. It appears that the macro
15 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
16 including that header, and restore its value afterwards. */
18 #ifdef USE_TCP_WRAPPERS
21 #define EXIM_HAVE_IPV6
27 #define HAVE_IPV6 TRUE
30 int allow_severity = LOG_INFO;
31 int deny_severity = LOG_NOTICE;
32 uschar *tcp_wrappers_name;
36 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
37 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
38 commands that accept arguments, and this in particular applies to AUTH, where
39 the data can be quite long. More recently this value was 2048 in Exim;
40 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
41 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
42 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
43 we need room to handle large base64-encoded AUTHs for GSSAPI.
46 #define smtp_cmd_buffer_size 16384
48 /* Size of buffer for reading SMTP incoming packets */
50 #define in_buffer_size 8192
52 /* Structure for SMTP command list */
59 short int is_mail_cmd;
62 /* Codes for identifying commands. We order them so that those that come first
63 are those for which synchronization is always required. Checking this can help
67 /* These commands are required to be synchronized, i.e. to be the last in a
68 block of commands when pipelining. */
70 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
71 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
72 ETRN_CMD, /* This by analogy with TURN from the RFC */
73 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 /* This is a dummy to identify the non-sync commands when pipelining */
77 NON_SYNC_CMD_PIPELINING,
79 /* These commands need not be synchronized when pipelining */
81 MAIL_CMD, RCPT_CMD, RSET_CMD,
83 /* This is a dummy to identify the non-sync commands when not pipelining */
85 NON_SYNC_CMD_NON_PIPELINING,
87 /* I have been unable to find a statement about the use of pipelining
88 with AUTH, so to be on the safe side it is here, though I kind of feel
89 it should be up there with the synchronized commands. */
93 /* I'm not sure about these, but I don't think they matter. */
97 /* These are specials that don't correspond to actual commands */
99 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
100 TOO_MANY_NONMAIL_CMD };
103 /* This is a convenience macro for adding the identity of an SMTP command
104 to the circular buffer that holds a list of the last n received. */
107 smtp_connection_had[smtp_ch_index++] = n; \
108 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
111 /*************************************************
112 * Local static variables *
113 *************************************************/
115 static auth_instance *authenticated_by;
116 static BOOL auth_advertised;
118 static BOOL tls_advertised;
121 static BOOL helo_required = FALSE;
122 static BOOL helo_verify = FALSE;
123 static BOOL helo_seen;
124 static BOOL helo_accept_junk;
125 static BOOL count_nonmail;
126 static BOOL pipelining_advertised;
127 static BOOL rcpt_smtp_response_same;
128 static BOOL rcpt_in_progress;
129 static int nonmail_command_count;
130 static BOOL smtp_exit_function_called = 0;
131 static int synprot_error_count;
132 static int unknown_command_count;
133 static int sync_cmd_limit;
134 static int smtp_write_error = 0;
136 static uschar *rcpt_smtp_response;
137 static uschar *smtp_data_buffer;
138 static uschar *smtp_cmd_data;
140 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
141 final fields of all except AUTH are forced TRUE at the start of a new message
142 setup, to allow one of each between messages that is not counted as a nonmail
143 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
144 allow a new EHLO after starting up TLS.
146 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
147 counted. However, the flag is changed when AUTH is received, so that multiple
148 failing AUTHs will eventually hit the limit. After a successful AUTH, another
149 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
150 forced TRUE, to allow for the re-authentication that can happen at that point.
152 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
153 count of non-mail commands and possibly provoke an error. */
155 static smtp_cmd_list cmd_list[] = {
156 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
157 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
158 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
159 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
161 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
164 /* If you change anything above here, also fix the definitions below. */
166 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
167 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
168 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
169 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
170 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
171 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
172 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
173 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
174 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
177 static smtp_cmd_list *cmd_list_end =
178 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
180 #define CMD_LIST_RSET 0
181 #define CMD_LIST_HELO 1
182 #define CMD_LIST_EHLO 2
183 #define CMD_LIST_AUTH 3
184 #define CMD_LIST_STARTTLS 4
186 /* This list of names is used for performing the smtp_no_mail logging action.
187 It must be kept in step with the SCH_xxx enumerations. */
189 static uschar *smtp_names[] =
191 US"NONE", US"AUTH", US"DATA", US"EHLO", US"ETRN", US"EXPN", US"HELO",
192 US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", US"STARTTLS",
195 static uschar *protocols[] = {
196 US"local-smtp", /* HELO */
197 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
198 US"local-esmtp", /* EHLO */
199 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
200 US"local-esmtpa", /* EHLO->AUTH */
201 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
206 #define pcrpted 1 /* added to pextend or pnormal */
207 #define pauthed 2 /* added to pextend */
208 #define pnlocal 6 /* offset to remove "local" */
210 /* Sanity check and validate optional args to MAIL FROM: envelope */
212 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
213 ENV_MAIL_OPT_PRDR, ENV_MAIL_OPT_NULL
216 uschar * name; /* option requested during MAIL cmd */
217 int value; /* enum type */
218 BOOL need_value; /* TRUE requires value (name=value pair format)
219 FALSE is a singleton */
221 static env_mail_type_t env_mail_type_list[] = {
222 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
223 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
224 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
225 { US"NULL", ENV_MAIL_OPT_NULL, FALSE } /* Placeholder for ending */
228 /* When reading SMTP from a remote host, we have to use our own versions of the
229 C input-reading functions, in order to be able to flush the SMTP output only
230 when about to read more data from the socket. This is the only way to get
231 optimal performance when the client is using pipelining. Flushing for every
232 command causes a separate packet and reply packet each time; saving all the
233 responses up (when pipelining) combines them into one packet and one response.
235 For simplicity, these functions are used for *all* SMTP input, not only when
236 receiving over a socket. However, after setting up a secure socket (SSL), input
237 is read via the OpenSSL library, and another set of functions is used instead
240 These functions are set in the receive_getc etc. variables and called with the
241 same interface as the C functions. However, since there can only ever be
242 one incoming SMTP call, we just use a single buffer and flags. There is no need
243 to implement a complicated private FILE-like structure.*/
245 static uschar *smtp_inbuffer;
246 static uschar *smtp_inptr;
247 static uschar *smtp_inend;
248 static int smtp_had_eof;
249 static int smtp_had_error;
252 /*************************************************
253 * SMTP version of getc() *
254 *************************************************/
256 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
257 it flushes the output, and refills the buffer, with a timeout. The signal
258 handler is set appropriately by the calling function. This function is not used
259 after a connection has negotated itself into an TLS/SSL state.
262 Returns: the next character or EOF
268 if (smtp_inptr >= smtp_inend)
272 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
273 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
278 /* Must put the error text in fixed store, because this might be during
279 header reading, where it releases unused store above the header. */
282 smtp_had_error = save_errno;
283 smtp_read_error = string_copy_malloc(
284 string_sprintf(" (error: %s)", strerror(save_errno)));
286 else smtp_had_eof = 1;
290 dkim_exim_verify_feed(smtp_inbuffer, rc);
292 smtp_inend = smtp_inbuffer + rc;
293 smtp_inptr = smtp_inbuffer;
295 return *smtp_inptr++;
300 /*************************************************
301 * SMTP version of ungetc() *
302 *************************************************/
304 /* Puts a character back in the input buffer. Only ever
310 Returns: the character
316 *(--smtp_inptr) = ch;
323 /*************************************************
324 * SMTP version of feof() *
325 *************************************************/
327 /* Tests for a previous EOF
330 Returns: non-zero if the eof flag is set
342 /*************************************************
343 * SMTP version of ferror() *
344 *************************************************/
346 /* Tests for a previous read error, and returns with errno
347 restored to what it was when the error was detected.
350 Returns: non-zero if the error flag is set
356 errno = smtp_had_error;
357 return smtp_had_error;
362 /*************************************************
363 * Test for characters in the SMTP buffer *
364 *************************************************/
366 /* Used at the end of a message
375 return smtp_inptr < smtp_inend;
380 /*************************************************
381 * Write formatted string to SMTP channel *
382 *************************************************/
384 /* This is a separate function so that we don't have to repeat everything for
385 TLS support or debugging. It is global so that the daemon and the
386 authentication functions can use it. It does not return any error indication,
387 because major problems such as dropped connections won't show up till an output
388 flush for non-TLS connections. The smtp_fflush() function is available for
389 checking that: for convenience, TLS output errors are remembered here so that
390 they are also picked up later by smtp_fflush().
394 ... optional arguments
400 smtp_printf(const char *format, ...)
404 va_start(ap, format);
405 smtp_vprintf(format, ap);
409 /* This is split off so that verify.c:respond_printf() can, in effect, call
410 smtp_printf(), bearing in mind that in C a vararg function can't directly
411 call another vararg function, only a function which accepts a va_list. */
414 smtp_vprintf(const char *format, va_list ap)
418 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
422 void *reset_point = store_get(0);
423 uschar *msg_copy, *cr, *end;
424 msg_copy = string_copy(big_buffer);
425 end = msg_copy + Ustrlen(msg_copy);
426 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
427 memmove(cr, cr + 1, (end--) - cr);
428 debug_printf("SMTP>> %s", msg_copy);
429 store_reset(reset_point);
434 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
435 smtp_closedown(US"Unexpected error");
436 exim_exit(EXIT_FAILURE);
439 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
440 have had the same. Note: this code is also present in smtp_respond(). It would
441 be tidier to have it only in one place, but when it was added, it was easier to
442 do it that way, so as not to have to mess with the code for the RCPT command,
443 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
445 if (rcpt_in_progress)
447 if (rcpt_smtp_response == NULL)
448 rcpt_smtp_response = string_copy(big_buffer);
449 else if (rcpt_smtp_response_same &&
450 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
451 rcpt_smtp_response_same = FALSE;
452 rcpt_in_progress = FALSE;
455 /* Now write the string */
460 if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
465 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
470 /*************************************************
471 * Flush SMTP out and check for error *
472 *************************************************/
474 /* This function isn't currently used within Exim (it detects errors when it
475 tries to read the next SMTP input), but is available for use in local_scan().
476 For non-TLS connections, it flushes the output and checks for errors. For
477 TLS-connections, it checks for a previously-detected TLS write error.
480 Returns: 0 for no error; -1 after an error
486 if (tls_active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
487 return smtp_write_error;
492 /*************************************************
493 * SMTP command read timeout *
494 *************************************************/
496 /* Signal handler for timing out incoming SMTP commands. This attempts to
499 Argument: signal number (SIGALRM)
504 command_timeout_handler(int sig)
506 sig = sig; /* Keep picky compilers happy */
507 log_write(L_lost_incoming_connection,
508 LOG_MAIN, "SMTP command timeout on%s connection from %s",
509 (tls_active >= 0)? " TLS" : "",
510 host_and_ident(FALSE));
511 if (smtp_batched_input)
512 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
513 smtp_notquit_exit(US"command-timeout", US"421",
514 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
515 exim_exit(EXIT_FAILURE);
520 /*************************************************
522 *************************************************/
524 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
526 Argument: signal number (SIGTERM)
531 command_sigterm_handler(int sig)
533 sig = sig; /* Keep picky compilers happy */
534 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
535 if (smtp_batched_input)
536 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
537 smtp_notquit_exit(US"signal-exit", US"421",
538 US"%s: Service not available - closing connection", smtp_active_hostname);
539 exim_exit(EXIT_FAILURE);
545 /*************************************************
546 * Read one command line *
547 *************************************************/
549 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
550 There are sites that don't do this, and in any case internal SMTP probably
551 should check only for LF. Consequently, we check here for LF only. The line
552 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
553 an unknown command. The command is read into the global smtp_cmd_buffer so that
554 it is available via $smtp_command.
556 The character reading routine sets up a timeout for each block actually read
557 from the input (which may contain more than one command). We set up a special
558 signal handler that closes down the session on a timeout. Control does not
562 check_sync if TRUE, check synchronization rules if global option is TRUE
564 Returns: a code identifying the command (enumerated above)
568 smtp_read_command(BOOL check_sync)
573 BOOL hadnull = FALSE;
575 os_non_restarting_signal(SIGALRM, command_timeout_handler);
577 while ((c = (receive_getc)()) != '\n' && c != EOF)
579 if (ptr >= smtp_cmd_buffer_size)
581 os_non_restarting_signal(SIGALRM, sigalrm_handler);
589 smtp_cmd_buffer[ptr++] = c;
592 receive_linecount++; /* For BSMTP errors */
593 os_non_restarting_signal(SIGALRM, sigalrm_handler);
595 /* If hit end of file, return pseudo EOF command. Whether we have a
596 part-line already read doesn't matter, since this is an error state. */
598 if (c == EOF) return EOF_CMD;
600 /* Remove any CR and white space at the end of the line, and terminate the
603 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
604 smtp_cmd_buffer[ptr] = 0;
606 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
608 /* NULLs are not allowed in SMTP commands */
610 if (hadnull) return BADCHAR_CMD;
612 /* Scan command list and return identity, having set the data pointer
613 to the start of the actual data characters. Check for SMTP synchronization
616 for (p = cmd_list; p < cmd_list_end; p++)
618 if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
619 (smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
620 smtp_cmd_buffer[p->len] == 0 ||
621 smtp_cmd_buffer[p->len] == ' '))
623 if (smtp_inptr < smtp_inend && /* Outstanding input */
624 p->cmd < sync_cmd_limit && /* Command should sync */
625 check_sync && /* Local flag set */
626 smtp_enforce_sync && /* Global flag set */
627 sender_host_address != NULL && /* Not local input */
628 !sender_host_notsocket) /* Really is a socket */
631 /* The variables $smtp_command and $smtp_command_argument point into the
632 unmodified input buffer. A copy of the latter is taken for actual
633 processing, so that it can be chopped up into separate parts if necessary,
634 for example, when processing a MAIL command options such as SIZE that can
635 follow the sender address. */
637 smtp_cmd_argument = smtp_cmd_buffer + p->len;
638 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
639 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
640 smtp_cmd_data = smtp_data_buffer;
642 /* Count non-mail commands from those hosts that are controlled in this
643 way. The default is all hosts. We don't waste effort checking the list
644 until we get a non-mail command, but then cache the result to save checking
645 again. If there's a DEFER while checking the host, assume it's in the list.
647 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
648 start of each incoming message by fiddling with the value in the table. */
652 if (count_nonmail == TRUE_UNSET) count_nonmail =
653 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
654 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
655 return TOO_MANY_NONMAIL_CMD;
658 /* If there is data for a command that does not expect it, generate the
661 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
665 /* Enforce synchronization for unknown commands */
667 if (smtp_inptr < smtp_inend && /* Outstanding input */
668 check_sync && /* Local flag set */
669 smtp_enforce_sync && /* Global flag set */
670 sender_host_address != NULL && /* Not local input */
671 !sender_host_notsocket) /* Really is a socket */
679 /*************************************************
680 * Recheck synchronization *
681 *************************************************/
683 /* Synchronization checks can never be perfect because a packet may be on its
684 way but not arrived when the check is done. Such checks can in any case only be
685 done when TLS is not in use. Normally, the checks happen when commands are
686 read: Exim ensures that there is no more input in the input buffer. In normal
687 cases, the response to the command will be fast, and there is no further check.
689 However, for some commands an ACL is run, and that can include delays. In those
690 cases, it is useful to do another check on the input just before sending the
691 response. This also applies at the start of a connection. This function does
692 that check by means of the select() function, as long as the facility is not
693 disabled or inappropriate. A failure of select() is ignored.
695 When there is unwanted input, we read it so that it appears in the log of the
699 Returns: TRUE if all is well; FALSE if there is input pending
707 struct timeval tzero;
709 if (!smtp_enforce_sync || sender_host_address == NULL ||
710 sender_host_notsocket || tls_active >= 0)
713 fd = fileno(smtp_in);
718 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
720 if (rc <= 0) return TRUE; /* Not ready to read */
722 if (rc < 0) return TRUE; /* End of file or error */
725 rc = smtp_inend - smtp_inptr;
726 if (rc > 150) rc = 150;
733 /*************************************************
734 * Forced closedown of call *
735 *************************************************/
737 /* This function is called from log.c when Exim is dying because of a serious
738 disaster, and also from some other places. If an incoming non-batched SMTP
739 channel is open, it swallows the rest of the incoming message if in the DATA
740 phase, sends the reply string, and gives an error to all subsequent commands
741 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
745 message SMTP reply string to send, excluding the code
751 smtp_closedown(uschar *message)
753 if (smtp_in == NULL || smtp_batched_input) return;
754 receive_swallow_smtp();
755 smtp_printf("421 %s\r\n", message);
759 switch(smtp_read_command(FALSE))
765 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
770 smtp_printf("250 Reset OK\r\n");
774 smtp_printf("421 %s\r\n", message);
783 /*************************************************
784 * Set up connection info for logging *
785 *************************************************/
787 /* This function is called when logging information about an SMTP connection.
788 It sets up appropriate source information, depending on the type of connection.
789 If sender_fullhost is NULL, we are at a very early stage of the connection;
790 just use the IP address.
793 Returns: a string describing the connection
797 smtp_get_connection_info(void)
799 uschar *hostname = (sender_fullhost == NULL)?
800 sender_host_address : sender_fullhost;
803 return string_sprintf("SMTP connection from %s", hostname);
805 if (sender_host_unknown || sender_host_notsocket)
806 return string_sprintf("SMTP connection from %s", sender_ident);
809 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
811 if ((log_extra_selector & LX_incoming_interface) != 0 &&
812 interface_address != NULL)
813 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
814 interface_address, interface_port);
816 return string_sprintf("SMTP connection from %s", hostname);
821 /*************************************************
822 * Log lack of MAIL if so configured *
823 *************************************************/
825 /* This function is called when an SMTP session ends. If the log selector
826 smtp_no_mail is set, write a log line giving some details of what has happened
834 smtp_log_no_mail(void)
839 if (smtp_mailcmd_count > 0 || (log_extra_selector & LX_smtp_no_mail) == 0)
845 if (sender_host_authenticated != NULL)
847 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
848 if (authenticated_id != NULL)
849 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
853 if ((log_extra_selector & LX_tls_cipher) != 0 && tls_cipher != NULL)
854 s = string_append(s, &size, &ptr, 2, US" X=", tls_cipher);
855 if ((log_extra_selector & LX_tls_certificate_verified) != 0 &&
857 s = string_append(s, &size, &ptr, 2, US" CV=",
858 tls_certificate_verified? "yes":"no");
859 if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_peerdn != NULL)
860 s = string_append(s, &size, &ptr, 3, US" DN=\"",
861 string_printing(tls_peerdn), US"\"");
862 if ((log_extra_selector & LX_tls_sni) != 0 && tls_sni != NULL)
863 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
864 string_printing(tls_sni), US"\"");
867 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
868 US" C=..." : US" C=";
869 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
871 if (smtp_connection_had[i] != SCH_NONE)
873 s = string_append(s, &size, &ptr, 2, sep,
874 smtp_names[smtp_connection_had[i]]);
879 for (i = 0; i < smtp_ch_index; i++)
881 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
885 if (s != NULL) s[ptr] = 0; else s = US"";
886 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
887 host_and_ident(FALSE),
888 readconf_printtime(time(NULL) - smtp_connection_start), s);
893 /*************************************************
894 * Check HELO line and set sender_helo_name *
895 *************************************************/
897 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
898 the domain name of the sending host, or an ip literal in square brackets. The
899 arrgument is placed in sender_helo_name, which is in malloc store, because it
900 must persist over multiple incoming messages. If helo_accept_junk is set, this
901 host is permitted to send any old junk (needed for some broken hosts).
902 Otherwise, helo_allow_chars can be used for rogue characters in general
903 (typically people want to let in underscores).
906 s the data portion of the line (already past any white space)
908 Returns: TRUE or FALSE
912 check_helo(uschar *s)
915 uschar *end = s + Ustrlen(s);
916 BOOL yield = helo_accept_junk;
918 /* Discard any previous helo name */
920 if (sender_helo_name != NULL)
922 store_free(sender_helo_name);
923 sender_helo_name = NULL;
926 /* Skip tests if junk is permitted. */
930 /* Allow the new standard form for IPv6 address literals, namely,
931 [IPv6:....], and because someone is bound to use it, allow an equivalent
932 IPv4 form. Allow plain addresses as well. */
939 if (strncmpic(s, US"[IPv6:", 6) == 0)
940 yield = (string_is_ip_address(s+6, NULL) == 6);
941 else if (strncmpic(s, US"[IPv4:", 6) == 0)
942 yield = (string_is_ip_address(s+6, NULL) == 4);
944 yield = (string_is_ip_address(s+1, NULL) != 0);
949 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
950 that have been configured (usually underscore - sigh). */
957 if (!isalnum(*s) && *s != '.' && *s != '-' &&
958 Ustrchr(helo_allow_chars, *s) == NULL)
968 /* Save argument if OK */
970 if (yield) sender_helo_name = string_copy_malloc(start);
978 /*************************************************
979 * Extract SMTP command option *
980 *************************************************/
982 /* This function picks the next option setting off the end of smtp_cmd_data. It
983 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
984 things that can appear there.
987 name point this at the name
988 value point this at the data string
990 Returns: TRUE if found an option
994 extract_option(uschar **name, uschar **value)
997 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
998 while (isspace(*v)) v--;
1001 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1002 if (*v != '=') return FALSE;
1005 while(isalpha(n[-1])) n--;
1007 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1008 if (!isspace(n[-1])) return FALSE;
1021 /*************************************************
1022 * Reset for new message *
1023 *************************************************/
1025 /* This function is called whenever the SMTP session is reset from
1026 within either of the setup functions.
1028 Argument: the stacking pool storage reset point
1033 smtp_reset(void *reset_point)
1035 store_reset(reset_point);
1036 recipients_list = NULL;
1037 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1038 raw_recipients_count = recipients_count = recipients_list_max = 0;
1039 message_linecount = 0;
1041 acl_added_headers = NULL;
1042 queue_only_policy = FALSE;
1043 rcpt_smtp_response = NULL;
1044 rcpt_smtp_response_same = TRUE;
1045 rcpt_in_progress = FALSE;
1046 deliver_freeze = FALSE; /* Can be set by ACL */
1047 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1048 fake_response = OK; /* Can be set by ACL */
1049 #ifdef WITH_CONTENT_SCAN
1050 no_mbox_unspool = FALSE; /* Can be set by ACL */
1052 submission_mode = FALSE; /* Can be set by ACL */
1053 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1054 active_local_from_check = local_from_check; /* Can be set by ACL */
1055 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1056 sender_address = NULL;
1057 submission_name = NULL; /* Can be set by ACL */
1058 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1059 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1060 sender_verified_list = NULL; /* No senders verified */
1061 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1062 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1063 authenticated_sender = NULL;
1064 #ifdef EXPERIMENTAL_BRIGHTMAIL
1066 bmi_verdicts = NULL;
1068 #ifndef DISABLE_DKIM
1069 dkim_signers = NULL;
1070 dkim_disable_verify = FALSE;
1071 dkim_collect_input = FALSE;
1073 #ifdef EXPERIMENTAL_SPF
1074 spf_header_comment = NULL;
1075 spf_received = NULL;
1077 spf_smtp_comment = NULL;
1079 body_linecount = body_zerocount = 0;
1081 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1082 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1083 /* Note that ratelimiters_conn persists across resets. */
1085 /* Reset message ACL variables */
1089 /* The message body variables use malloc store. They may be set if this is
1090 not the first message in an SMTP session and the previous message caused them
1091 to be referenced in an ACL. */
1093 if (message_body != NULL)
1095 store_free(message_body);
1096 message_body = NULL;
1099 if (message_body_end != NULL)
1101 store_free(message_body_end);
1102 message_body_end = NULL;
1105 /* Warning log messages are also saved in malloc store. They are saved to avoid
1106 repetition in the same message, but it seems right to repeat them for different
1109 while (acl_warn_logged != NULL)
1111 string_item *this = acl_warn_logged;
1112 acl_warn_logged = acl_warn_logged->next;
1121 /*************************************************
1122 * Initialize for incoming batched SMTP message *
1123 *************************************************/
1125 /* This function is called from smtp_setup_msg() in the case when
1126 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1127 of messages in one file with SMTP commands between them. All errors must be
1128 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1129 relevant. After an error on a sender, or an invalid recipient, the remainder
1130 of the message is skipped. The value of received_protocol is already set.
1133 Returns: > 0 message successfully started (reached DATA)
1134 = 0 QUIT read or end of file reached
1135 < 0 should not occur
1139 smtp_setup_batch_msg(void)
1142 void *reset_point = store_get(0);
1144 /* Save the line count at the start of each transaction - single commands
1145 like HELO and RSET count as whole transactions. */
1147 bsmtp_transaction_linecount = receive_linecount;
1149 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1151 smtp_reset(reset_point); /* Reset for start of message */
1153 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1154 value. The values are 2 larger than the required yield of the function. */
1159 uschar *recipient = NULL;
1160 int start, end, sender_domain, recipient_domain;
1162 switch(smtp_read_command(FALSE))
1164 /* The HELO/EHLO commands set sender_address_helo if they have
1165 valid data; otherwise they are ignored, except that they do
1166 a reset of the state. */
1171 check_helo(smtp_cmd_data);
1175 smtp_reset(reset_point);
1176 bsmtp_transaction_linecount = receive_linecount;
1180 /* The MAIL FROM command requires an address as an operand. All we
1181 do here is to parse it for syntactic correctness. The form "<>" is
1182 a special case which converts into an empty string. The start/end
1183 pointers in the original are not used further for this address, as
1184 it is the canonical extracted address which is all that is kept. */
1187 if (sender_address != NULL)
1188 /* The function moan_smtp_batch() does not return. */
1189 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1191 if (smtp_cmd_data[0] == 0)
1192 /* The function moan_smtp_batch() does not return. */
1193 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1195 /* Reset to start of message */
1197 smtp_reset(reset_point);
1199 /* Apply SMTP rewrite */
1201 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1202 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1203 US"", global_rewrite_rules) : smtp_cmd_data;
1205 /* Extract the address; the TRUE flag allows <> as valid */
1208 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1211 if (raw_sender == NULL)
1212 /* The function moan_smtp_batch() does not return. */
1213 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1215 sender_address = string_copy(raw_sender);
1217 /* Qualify unqualified sender addresses if permitted to do so. */
1219 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1221 if (allow_unqualified_sender)
1223 sender_address = rewrite_address_qualify(sender_address, FALSE);
1224 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1225 "and rewritten\n", raw_sender);
1227 /* The function moan_smtp_batch() does not return. */
1228 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1234 /* The RCPT TO command requires an address as an operand. All we do
1235 here is to parse it for syntactic correctness. There may be any number
1236 of RCPT TO commands, specifying multiple senders. We build them all into
1237 a data structure that is in argc/argv format. The start/end values
1238 given by parse_extract_address are not used, as we keep only the
1239 extracted address. */
1242 if (sender_address == NULL)
1243 /* The function moan_smtp_batch() does not return. */
1244 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1246 if (smtp_cmd_data[0] == 0)
1247 /* The function moan_smtp_batch() does not return. */
1248 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1250 /* Check maximum number allowed */
1252 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1253 /* The function moan_smtp_batch() does not return. */
1254 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1255 recipients_max_reject? "552": "452");
1257 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1258 recipient address */
1260 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1261 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1262 global_rewrite_rules) : smtp_cmd_data;
1264 /* rfc821_domains = TRUE; << no longer needed */
1265 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1266 &recipient_domain, FALSE);
1267 /* rfc821_domains = FALSE; << no longer needed */
1269 if (recipient == NULL)
1270 /* The function moan_smtp_batch() does not return. */
1271 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1273 /* If the recipient address is unqualified, qualify it if permitted. Then
1274 add it to the list of recipients. */
1276 if (recipient_domain == 0)
1278 if (allow_unqualified_recipient)
1280 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1282 recipient = rewrite_address_qualify(recipient, TRUE);
1284 /* The function moan_smtp_batch() does not return. */
1285 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1288 receive_add_recipient(recipient, -1);
1292 /* The DATA command is legal only if it follows successful MAIL FROM
1293 and RCPT TO commands. This function is complete when a valid DATA
1294 command is encountered. */
1297 if (sender_address == NULL || recipients_count <= 0)
1299 /* The function moan_smtp_batch() does not return. */
1300 if (sender_address == NULL)
1301 moan_smtp_batch(smtp_cmd_buffer,
1302 "503 MAIL FROM:<sender> command must precede DATA");
1304 moan_smtp_batch(smtp_cmd_buffer,
1305 "503 RCPT TO:<recipient> must precede DATA");
1309 done = 3; /* DATA successfully achieved */
1310 message_ended = END_NOTENDED; /* Indicate in middle of message */
1315 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1322 bsmtp_transaction_linecount = receive_linecount;
1333 /* The function moan_smtp_batch() does not return. */
1334 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1339 /* The function moan_smtp_batch() does not return. */
1340 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1345 /* The function moan_smtp_batch() does not return. */
1346 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1351 return done - 2; /* Convert yield values */
1357 /*************************************************
1358 * Start an SMTP session *
1359 *************************************************/
1361 /* This function is called at the start of an SMTP session. Thereafter,
1362 smtp_setup_msg() is called to initiate each separate message. This
1363 function does host-specific testing, and outputs the banner line.
1366 Returns: FALSE if the session can not continue; something has
1367 gone wrong, or the connection to the host is blocked
1371 smtp_start_session(void)
1375 uschar *user_msg, *log_msg;
1379 smtp_connection_start = time(NULL);
1380 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1381 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1384 /* Default values for certain variables */
1386 helo_seen = esmtp = helo_accept_junk = FALSE;
1387 smtp_mailcmd_count = 0;
1388 count_nonmail = TRUE_UNSET;
1389 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1390 smtp_delay_mail = smtp_rlm_base;
1391 auth_advertised = FALSE;
1392 pipelining_advertised = FALSE;
1393 pipelining_enable = TRUE;
1394 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1395 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1397 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1399 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1400 authentication settings from -oMaa to remain in force. */
1402 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1403 authenticated_by = NULL;
1406 tls_cipher = tls_peerdn = NULL;
1407 tls_advertised = FALSE;
1410 /* Reset ACL connection variables */
1414 /* Allow for trailing 0 in the command and data buffers. */
1416 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1417 if (smtp_cmd_buffer == NULL)
1418 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1419 "malloc() failed for SMTP command buffer");
1420 smtp_cmd_buffer[0] = 0;
1421 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1423 /* For batched input, the protocol setting can be overridden from the
1424 command line by a trusted caller. */
1426 if (smtp_batched_input)
1428 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1431 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1432 reset later if any of EHLO/AUTH/STARTTLS are received. */
1436 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1438 /* Set up the buffer for inputting using direct read() calls, and arrange to
1439 call the local functions instead of the standard C ones. */
1441 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1442 if (smtp_inbuffer == NULL)
1443 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1444 receive_getc = smtp_getc;
1445 receive_ungetc = smtp_ungetc;
1446 receive_feof = smtp_feof;
1447 receive_ferror = smtp_ferror;
1448 receive_smtp_buffered = smtp_buffered;
1449 smtp_inptr = smtp_inend = smtp_inbuffer;
1450 smtp_had_eof = smtp_had_error = 0;
1452 /* Set up the message size limit; this may be host-specific */
1454 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1455 if (expand_string_message != NULL)
1457 if (thismessage_size_limit == -1)
1458 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1459 "%s", expand_string_message);
1461 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1462 "%s", expand_string_message);
1463 smtp_closedown(US"Temporary local problem - please try later");
1467 /* When a message is input locally via the -bs or -bS options, sender_host_
1468 unknown is set unless -oMa was used to force an IP address, in which case it
1469 is checked like a real remote connection. When -bs is used from inetd, this
1470 flag is not set, causing the sending host to be checked. The code that deals
1471 with IP source routing (if configured) is never required for -bs or -bS and
1472 the flag sender_host_notsocket is used to suppress it.
1474 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1475 reserve for certain hosts and/or networks. */
1477 if (!sender_host_unknown)
1480 BOOL reserved_host = FALSE;
1482 /* Look up IP options (source routing info) on the socket if this is not an
1483 -oMa "host", and if any are found, log them and drop the connection.
1485 Linux (and others now, see below) is different to everyone else, so there
1486 has to be some conditional compilation here. Versions of Linux before 2.1.15
1487 used a structure whose name was "options". Somebody finally realized that
1488 this name was silly, and it got changed to "ip_options". I use the
1489 newer name here, but there is a fudge in the script that sets up os.h
1490 to define a macro in older Linux systems.
1492 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1493 glibc 2, which has chosen ip_opts for the structure name. This is now
1494 really a glibc thing rather than a Linux thing, so the condition name
1495 has been changed to reflect this. It is relevant also to GNU/Hurd.
1497 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1498 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1499 a special macro defined in the os.h file.
1501 Some DGUX versions on older hardware appear not to support IP options at
1502 all, so there is now a general macro which can be set to cut out this
1505 How to do this properly in IPv6 is not yet known. */
1507 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1509 #ifdef GLIBC_IP_OPTIONS
1510 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1515 #elif defined DARWIN_IP_OPTIONS
1521 if (!host_checking && !sender_host_notsocket)
1524 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1525 struct ip_options *ipopt = store_get(optlen);
1527 struct ip_opts ipoptblock;
1528 struct ip_opts *ipopt = &ipoptblock;
1529 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1531 struct ipoption ipoptblock;
1532 struct ipoption *ipopt = &ipoptblock;
1533 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1536 /* Occasional genuine failures of getsockopt() have been seen - for
1537 example, "reset by peer". Therefore, just log and give up on this
1538 call, unless the error is ENOPROTOOPT. This error is given by systems
1539 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1540 of writing. So for that error, carry on - we just can't do an IP options
1543 DEBUG(D_receive) debug_printf("checking for IP options\n");
1545 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1548 if (errno != ENOPROTOOPT)
1550 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1551 host_and_ident(FALSE), strerror(errno));
1552 smtp_printf("451 SMTP service not available\r\n");
1557 /* Deal with any IP options that are set. On the systems I have looked at,
1558 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1559 more logging data than will fit in big_buffer. Nevertheless, after somebody
1560 questioned this code, I've added in some paranoid checking. */
1562 else if (optlen > 0)
1564 uschar *p = big_buffer;
1565 uschar *pend = big_buffer + big_buffer_size;
1566 uschar *opt, *adptr;
1568 struct in_addr addr;
1571 uschar *optstart = (uschar *)(ipopt->__data);
1573 uschar *optstart = (uschar *)(ipopt->ip_opts);
1575 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1578 DEBUG(D_receive) debug_printf("IP options exist\n");
1580 Ustrcpy(p, "IP options on incoming call:");
1583 for (opt = optstart; opt != NULL &&
1584 opt < (uschar *)(ipopt) + optlen;)
1598 if (!string_format(p, pend-p, " %s [@%s",
1599 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1601 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1603 inet_ntoa(ipopt->ip_dst)))
1605 inet_ntoa(ipopt->ipopt_dst)))
1613 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1615 while (optcount-- > 0)
1617 memcpy(&addr, adptr, sizeof(addr));
1618 if (!string_format(p, pend - p - 1, "%s%s",
1619 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1625 adptr += sizeof(struct in_addr);
1634 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1637 for (i = 0; i < opt[1]; i++)
1639 sprintf(CS p, "%2.2x ", opt[i]);
1650 log_write(0, LOG_MAIN, "%s", big_buffer);
1652 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1654 log_write(0, LOG_MAIN|LOG_REJECT,
1655 "connection from %s refused (IP options)", host_and_ident(FALSE));
1657 smtp_printf("554 SMTP service not available\r\n");
1661 /* Length of options = 0 => there are no options */
1663 else DEBUG(D_receive) debug_printf("no IP options found\n");
1665 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1667 /* Set keep-alive in socket options. The option is on by default. This
1668 setting is an attempt to get rid of some hanging connections that stick in
1669 read() when the remote end (usually a dialup) goes away. */
1671 if (smtp_accept_keepalive && !sender_host_notsocket)
1672 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1674 /* If the current host matches host_lookup, set the name by doing a
1675 reverse lookup. On failure, sender_host_name will be NULL and
1676 host_lookup_failed will be TRUE. This may or may not be serious - optional
1679 if (verify_check_host(&host_lookup) == OK)
1681 (void)host_name_lookup();
1682 host_build_sender_fullhost();
1685 /* Delay this until we have the full name, if it is looked up. */
1687 set_process_info("handling incoming connection from %s",
1688 host_and_ident(FALSE));
1690 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1691 smtps port for use with older style SSL MTAs. */
1694 if (tls_on_connect &&
1695 tls_server_start(tls_require_ciphers) != OK)
1699 /* Test for explicit connection rejection */
1701 if (verify_check_host(&host_reject_connection) == OK)
1703 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1704 "from %s (host_reject_connection)", host_and_ident(FALSE));
1705 smtp_printf("554 SMTP service not available\r\n");
1709 /* Test with TCP Wrappers if so configured. There is a problem in that
1710 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1711 such as disks dying. In these cases, it is desirable to reject with a 4xx
1712 error instead of a 5xx error. There isn't a "right" way to detect such
1713 problems. The following kludge is used: errno is zeroed before calling
1714 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1715 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1718 #ifdef USE_TCP_WRAPPERS
1720 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
1721 if (tcp_wrappers_name == NULL)
1723 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
1724 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
1725 expand_string_message);
1727 if (!hosts_ctl(tcp_wrappers_name,
1728 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1729 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1730 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1732 if (errno == 0 || errno == ENOENT)
1734 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1735 log_write(L_connection_reject,
1736 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1737 "(tcp wrappers)", host_and_ident(FALSE));
1738 smtp_printf("554 SMTP service not available\r\n");
1742 int save_errno = errno;
1743 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1744 "errno value %d\n", save_errno);
1745 log_write(L_connection_reject,
1746 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1747 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1748 smtp_printf("451 Temporary local problem - please try later\r\n");
1754 /* Check for reserved slots. The value of smtp_accept_count has already been
1755 incremented to include this process. */
1757 if (smtp_accept_max > 0 &&
1758 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
1760 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1762 log_write(L_connection_reject,
1763 LOG_MAIN, "temporarily refused connection from %s: not in "
1764 "reserve list: connected=%d max=%d reserve=%d%s",
1765 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
1766 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1767 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1768 "please try again later\r\n", smtp_active_hostname);
1771 reserved_host = TRUE;
1774 /* If a load level above which only messages from reserved hosts are
1775 accepted is set, check the load. For incoming calls via the daemon, the
1776 check is done in the superior process if there are no reserved hosts, to
1777 save a fork. In all cases, the load average will already be available
1778 in a global variable at this point. */
1780 if (smtp_load_reserve >= 0 &&
1781 load_average > smtp_load_reserve &&
1783 verify_check_host(&smtp_reserve_hosts) != OK)
1785 log_write(L_connection_reject,
1786 LOG_MAIN, "temporarily refused connection from %s: not in "
1787 "reserve list and load average = %.2f", host_and_ident(FALSE),
1788 (double)load_average/1000.0);
1789 smtp_printf("421 %s: Too much load; please try again later\r\n",
1790 smtp_active_hostname);
1794 /* Determine whether unqualified senders or recipients are permitted
1795 for this host. Unfortunately, we have to do this every time, in order to
1796 set the flags so that they can be inspected when considering qualifying
1797 addresses in the headers. For a site that permits no qualification, this
1798 won't take long, however. */
1800 allow_unqualified_sender =
1801 verify_check_host(&sender_unqualified_hosts) == OK;
1803 allow_unqualified_recipient =
1804 verify_check_host(&recipient_unqualified_hosts) == OK;
1806 /* Determine whether HELO/EHLO is required for this host. The requirement
1807 can be hard or soft. */
1809 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1811 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1813 /* Determine whether this hosts is permitted to send syntactic junk
1814 after a HELO or EHLO command. */
1816 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1819 /* For batch SMTP input we are now done. */
1821 if (smtp_batched_input) return TRUE;
1823 /* Run the ACL if it exists */
1826 if (acl_smtp_connect != NULL)
1829 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1833 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1838 /* Output the initial message for a two-way SMTP connection. It may contain
1839 newlines, which then cause a multi-line response to be given. */
1841 code = US"220"; /* Default status code */
1842 esc = US""; /* Default extended status code */
1843 esclen = 0; /* Length of esc */
1845 if (user_msg == NULL)
1847 s = expand_string(smtp_banner);
1849 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1850 "failed: %s", smtp_banner, expand_string_message);
1856 smtp_message_code(&code, &codelen, &s, NULL);
1860 esclen = codelen - 4;
1864 /* Remove any terminating newlines; might as well remove trailing space too */
1867 while (p > s && isspace(p[-1])) p--;
1870 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1871 is all contained in a single IP packet. The original code wrote out the
1872 greeting using several calls to fprint/fputc, and on busy servers this could
1873 cause it to be split over more than one packet - which caused CC:Mail to fall
1874 over when it got the second part of the greeting after sending its first
1875 command. Sigh. To try to avoid this, build the complete greeting message
1876 first, and output it in one fell swoop. This gives a better chance of it
1877 ending up as a single packet. */
1879 ss = store_get(size);
1883 do /* At least once, in case we have an empty string */
1886 uschar *linebreak = Ustrchr(p, '\n');
1887 ss = string_cat(ss, &size, &ptr, code, 3);
1888 if (linebreak == NULL)
1891 ss = string_cat(ss, &size, &ptr, US" ", 1);
1895 len = linebreak - p;
1896 ss = string_cat(ss, &size, &ptr, US"-", 1);
1898 ss = string_cat(ss, &size, &ptr, esc, esclen);
1899 ss = string_cat(ss, &size, &ptr, p, len);
1900 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1902 if (linebreak != NULL) p++;
1906 ss[ptr] = 0; /* string_cat leaves room for this */
1908 /* Before we write the banner, check that there is no input pending, unless
1909 this synchronisation check is disabled. */
1913 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1914 "synchronization error (input sent without waiting for greeting): "
1915 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1916 string_printing(smtp_inptr));
1917 smtp_printf("554 SMTP synchronization error\r\n");
1921 /* Now output the banner */
1923 smtp_printf("%s", ss);
1931 /*************************************************
1932 * Handle SMTP syntax and protocol errors *
1933 *************************************************/
1935 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1936 to do so. Then transmit the error response. The return value depends on the
1937 number of syntax and protocol errors in this SMTP session.
1940 type error type, given as a log flag bit
1941 code response code; <= 0 means don't send a response
1942 data data to reflect in the response (can be NULL)
1943 errmess the error message
1945 Returns: -1 limit of syntax/protocol errors NOT exceeded
1946 +1 limit of syntax/protocol errors IS exceeded
1948 These values fit in with the values of the "done" variable in the main
1949 processing loop in smtp_setup_msg(). */
1952 synprot_error(int type, int code, uschar *data, uschar *errmess)
1956 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1957 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1958 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1960 if (++synprot_error_count > smtp_max_synprot_errors)
1963 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1964 "syntax or protocol errors (last command was \"%s\")",
1965 host_and_ident(FALSE), smtp_cmd_buffer);
1970 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1971 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1973 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1982 /*************************************************
1983 * Log incomplete transactions *
1984 *************************************************/
1986 /* This function is called after a transaction has been aborted by RSET, QUIT,
1987 connection drops or other errors. It logs the envelope information received
1988 so far in order to preserve address verification attempts.
1990 Argument: string to indicate what aborted the transaction
1995 incomplete_transaction_log(uschar *what)
1997 if (sender_address == NULL || /* No transaction in progress */
1998 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
2001 /* Build list of recipients for logging */
2003 if (recipients_count > 0)
2006 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2007 for (i = 0; i < recipients_count; i++)
2008 raw_recipients[i] = recipients_list[i].address;
2009 raw_recipients_count = recipients_count;
2012 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2013 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2019 /*************************************************
2020 * Send SMTP response, possibly multiline *
2021 *************************************************/
2023 /* There are, it seems, broken clients out there that cannot handle multiline
2024 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2025 output nothing for non-final calls, and only the first line for anything else.
2028 code SMTP code, may involve extended status codes
2029 codelen length of smtp code; if > 4 there's an ESC
2030 final FALSE if the last line isn't the final line
2031 msg message text, possibly containing newlines
2037 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2042 if (!final && no_multiline_responses) return;
2047 esclen = codelen - 4;
2050 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2051 have had the same. Note: this code is also present in smtp_printf(). It would
2052 be tidier to have it only in one place, but when it was added, it was easier to
2053 do it that way, so as not to have to mess with the code for the RCPT command,
2054 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2056 if (rcpt_in_progress)
2058 if (rcpt_smtp_response == NULL)
2059 rcpt_smtp_response = string_copy(msg);
2060 else if (rcpt_smtp_response_same &&
2061 Ustrcmp(rcpt_smtp_response, msg) != 0)
2062 rcpt_smtp_response_same = FALSE;
2063 rcpt_in_progress = FALSE;
2066 /* Not output the message, splitting it up into multiple lines if necessary. */
2070 uschar *nl = Ustrchr(msg, '\n');
2073 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2076 else if (nl[1] == 0 || no_multiline_responses)
2078 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2079 (int)(nl - msg), msg);
2084 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2086 while (isspace(*msg)) msg++;
2094 /*************************************************
2095 * Parse user SMTP message *
2096 *************************************************/
2098 /* This function allows for user messages overriding the response code details
2099 by providing a suitable response code string at the start of the message
2100 user_msg. Check the message for starting with a response code and optionally an
2101 extended status code. If found, check that the first digit is valid, and if so,
2102 change the code pointer and length to use the replacement. An invalid code
2103 causes a panic log; in this case, if the log messages is the same as the user
2104 message, we must also adjust the value of the log message to show the code that
2105 is actually going to be used (the original one).
2107 This function is global because it is called from receive.c as well as within
2110 Note that the code length returned includes the terminating whitespace
2111 character, which is always included in the regex match.
2114 code SMTP code, may involve extended status codes
2115 codelen length of smtp code; if > 4 there's an ESC
2117 log_msg optional log message, to be adjusted with the new SMTP code
2123 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2128 if (msg == NULL || *msg == NULL) return;
2130 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2131 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2134 if ((*msg)[0] != (*code)[0])
2136 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2137 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2138 if (log_msg != NULL && *log_msg == *msg)
2139 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2144 *codelen = ovector[1]; /* Includes final space */
2146 *msg += ovector[1]; /* Chop the code off the message */
2153 /*************************************************
2154 * Handle an ACL failure *
2155 *************************************************/
2157 /* This function is called when acl_check() fails. As well as calls from within
2158 this module, it is called from receive.c for an ACL after DATA. It sorts out
2159 logging the incident, and sets up the error response. A message containing
2160 newlines is turned into a multiline SMTP response, but for logging, only the
2163 There's a table of default permanent failure response codes to use in
2164 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2165 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2166 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2167 state, because there are broken clients that try VRFY before RCPT. A 5xx
2168 response should be given only when the address is positively known to be
2169 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2172 From Exim 4.63, it is possible to override the response code details by
2173 providing a suitable response code string at the start of the message provided
2174 in user_msg. The code's first digit is checked for validity.
2177 where where the ACL was called from
2179 user_msg a message that can be included in an SMTP response
2180 log_msg a message for logging
2182 Returns: 0 in most cases
2183 2 if the failure code was FAIL_DROP, in which case the
2184 SMTP connection should be dropped (this value fits with the
2185 "done" variable in smtp_setup_msg() below)
2189 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2191 BOOL drop = rc == FAIL_DROP;
2195 uschar *sender_info = US"";
2197 #ifdef WITH_CONTENT_SCAN
2198 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2200 (where == ACL_WHERE_PREDATA)? US"DATA" :
2201 (where == ACL_WHERE_DATA)? US"after DATA" :
2202 (smtp_cmd_data == NULL)?
2203 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2204 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2206 if (drop) rc = FAIL;
2208 /* Set the default SMTP code, and allow a user message to change it. */
2210 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2211 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2213 /* We used to have sender_address here; however, there was a bug that was not
2214 updating sender_address after a rewrite during a verify. When this bug was
2215 fixed, sender_address at this point became the rewritten address. I'm not sure
2216 this is what should be logged, so I've changed to logging the unrewritten
2217 address to retain backward compatibility. */
2219 #ifndef WITH_CONTENT_SCAN
2220 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2222 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2225 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2226 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2227 sender_host_authenticated ? US" A=" : US"",
2228 sender_host_authenticated ? sender_host_authenticated : US"",
2229 sender_host_authenticated && authenticated_id ? US":" : US"",
2230 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2234 /* If there's been a sender verification failure with a specific message, and
2235 we have not sent a response about it yet, do so now, as a preliminary line for
2236 failures, but not defers. However, always log it for defer, and log it for fail
2237 unless the sender_verify_fail log selector has been turned off. */
2239 if (sender_verified_failed != NULL &&
2240 !testflag(sender_verified_failed, af_sverify_told))
2242 BOOL save_rcpt_in_progress = rcpt_in_progress;
2243 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2245 setflag(sender_verified_failed, af_sverify_told);
2247 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2248 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2249 host_and_ident(TRUE),
2250 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2251 sender_verified_failed->address,
2252 (sender_verified_failed->message == NULL)? US"" :
2253 string_sprintf(": %s", sender_verified_failed->message));
2255 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2256 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2257 testflag(sender_verified_failed, af_verify_pmfail)?
2258 "Postmaster verification failed while checking <%s>\n%s\n"
2259 "Several RFCs state that you are required to have a postmaster\n"
2260 "mailbox for each mail domain. This host does not accept mail\n"
2261 "from domains whose servers reject the postmaster address."
2263 testflag(sender_verified_failed, af_verify_nsfail)?
2264 "Callback setup failed while verifying <%s>\n%s\n"
2265 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2266 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2267 "RFC requirements, and stops you from receiving standard bounce\n"
2268 "messages. This host does not accept mail from domains whose servers\n"
2271 "Verification failed for <%s>\n%s",
2272 sender_verified_failed->address,
2273 sender_verified_failed->user_message));
2275 rcpt_in_progress = save_rcpt_in_progress;
2278 /* Sort out text for logging */
2280 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2281 lognl = Ustrchr(log_msg, '\n');
2282 if (lognl != NULL) *lognl = 0;
2284 /* Send permanent failure response to the command, but the code used isn't
2285 always a 5xx one - see comments at the start of this function. If the original
2286 rc was FAIL_DROP we drop the connection and yield 2. */
2288 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2289 US"Administrative prohibition" : user_msg);
2291 /* Send temporary failure response to the command. Don't give any details,
2292 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2293 verb, and for a header verify when smtp_return_error_details is set.
2295 This conditional logic is all somewhat of a mess because of the odd
2296 interactions between temp_details and return_error_details. One day it should
2297 be re-implemented in a tidier fashion. */
2301 if (acl_temp_details && user_msg != NULL)
2303 if (smtp_return_error_details &&
2304 sender_verified_failed != NULL &&
2305 sender_verified_failed->message != NULL)
2307 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2309 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2312 smtp_respond(smtp_code, codelen, TRUE,
2313 US"Temporary local problem - please try later");
2316 /* Log the incident to the logs that are specified by log_reject_target
2317 (default main, reject). This can be empty to suppress logging of rejections. If
2318 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2319 is closing if required and return 2. */
2321 if (log_reject_target != 0)
2322 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2323 host_and_ident(TRUE),
2324 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2326 if (!drop) return 0;
2328 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2329 smtp_get_connection_info());
2331 /* Run the not-quit ACL, but without any custom messages. This should not be a
2332 problem, because we get here only if some other ACL has issued "drop", and
2333 in that case, *its* custom messages will have been used above. */
2335 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2342 /*************************************************
2343 * Handle SMTP exit when QUIT is not given *
2344 *************************************************/
2346 /* This function provides a logging/statistics hook for when an SMTP connection
2347 is dropped on the floor or the other end goes away. It's a global function
2348 because it's called from receive.c as well as this module. As well as running
2349 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2350 response, either with a custom message from the ACL, or using a default. There
2351 is one case, however, when no message is output - after "drop". In that case,
2352 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2353 passed to this function.
2355 In case things go wrong while processing this function, causing an error that
2356 may re-enter this funtion, there is a recursion check.
2359 reason What $smtp_notquit_reason will be set to in the ACL;
2360 if NULL, the ACL is not run
2361 code The error code to return as part of the response
2362 defaultrespond The default message if there's no user_msg
2368 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2371 uschar *user_msg = NULL;
2372 uschar *log_msg = NULL;
2374 /* Check for recursive acll */
2376 if (smtp_exit_function_called)
2378 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2382 smtp_exit_function_called = TRUE;
2384 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2386 if (acl_smtp_notquit != NULL && reason != NULL)
2388 smtp_notquit_reason = reason;
2389 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2392 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2396 /* Write an SMTP response if we are expected to give one. As the default
2397 responses are all internal, they should always fit in the buffer, but code a
2398 warning, just in case. Note that string_vformat() still leaves a complete
2399 string, even if it is incomplete. */
2401 if (code != NULL && defaultrespond != NULL)
2403 if (user_msg == NULL)
2407 va_start(ap, defaultrespond);
2408 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2409 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2410 smtp_printf("%s %s\r\n", code, buffer);
2414 smtp_respond(code, 3, TRUE, user_msg);
2422 /*************************************************
2423 * Verify HELO argument *
2424 *************************************************/
2426 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2427 matched. It is also called from ACL processing if verify = helo is used and
2428 verification was not previously tried (i.e. helo_try_verify_hosts was not
2429 matched). The result of its processing is to set helo_verified and
2430 helo_verify_failed. These variables should both be FALSE for this function to
2433 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2434 for IPv6 ::ffff: literals.
2437 Returns: TRUE if testing was completed;
2438 FALSE on a temporary failure
2442 smtp_verify_helo(void)
2446 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2449 if (sender_helo_name == NULL)
2451 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2454 /* Deal with the case of -bs without an IP address */
2456 else if (sender_host_address == NULL)
2458 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2459 helo_verified = TRUE;
2462 /* Deal with the more common case when there is a sending IP address */
2464 else if (sender_helo_name[0] == '[')
2466 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2467 Ustrlen(sender_host_address)) == 0;
2472 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2473 helo_verified = Ustrncmp(sender_helo_name + 1,
2474 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2479 { if (helo_verified) debug_printf("matched host address\n"); }
2482 /* Do a reverse lookup if one hasn't already given a positive or negative
2483 response. If that fails, or the name doesn't match, try checking with a forward
2488 if (sender_host_name == NULL && !host_lookup_failed)
2489 yield = host_name_lookup() != DEFER;
2491 /* If a host name is known, check it and all its aliases. */
2493 if (sender_host_name != NULL)
2495 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2499 HDEBUG(D_receive) debug_printf("matched host name\n");
2503 uschar **aliases = sender_host_aliases;
2504 while (*aliases != NULL)
2506 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2507 if (helo_verified) break;
2512 debug_printf("matched alias %s\n", *(--aliases));
2517 /* Final attempt: try a forward lookup of the helo name */
2523 h.name = sender_helo_name;
2527 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2529 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2530 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2535 if (Ustrcmp(hh->address, sender_host_address) == 0)
2537 helo_verified = TRUE;
2539 debug_printf("IP address for %s matches calling address\n",
2549 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2556 /*************************************************
2557 * Send user response message *
2558 *************************************************/
2560 /* This function is passed a default response code and a user message. It calls
2561 smtp_message_code() to check and possibly modify the response code, and then
2562 calls smtp_respond() to transmit the response. I put this into a function
2563 just to avoid a lot of repetition.
2566 code the response code
2567 user_msg the user message
2573 smtp_user_msg(uschar *code, uschar *user_msg)
2576 smtp_message_code(&code, &len, &user_msg, NULL);
2577 smtp_respond(code, len, TRUE, user_msg);
2583 /*************************************************
2584 * Initialize for SMTP incoming message *
2585 *************************************************/
2587 /* This function conducts the initial dialogue at the start of an incoming SMTP
2588 message, and builds a list of recipients. However, if the incoming message
2589 is part of a batch (-bS option) a separate function is called since it would
2590 be messy having tests splattered about all over this function. This function
2591 therefore handles the case where interaction is occurring. The input and output
2592 files are set up in smtp_in and smtp_out.
2594 The global recipients_list is set to point to a vector of recipient_item
2595 blocks, whose number is given by recipients_count. This is extended by the
2596 receive_add_recipient() function. The global variable sender_address is set to
2597 the sender's address. The yield is +1 if a message has been successfully
2598 started, 0 if a QUIT command was encountered or the connection was refused from
2599 the particular host, or -1 if the connection was lost.
2603 Returns: > 0 message successfully started (reached DATA)
2604 = 0 QUIT read or end of file reached or call refused
2609 smtp_setup_msg(void)
2612 BOOL toomany = FALSE;
2613 BOOL discarded = FALSE;
2614 BOOL last_was_rej_mail = FALSE;
2615 BOOL last_was_rcpt = FALSE;
2616 void *reset_point = store_get(0);
2618 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2620 /* Reset for start of new message. We allow one RSET not to be counted as a
2621 nonmail command, for those MTAs that insist on sending it between every
2622 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2623 TLS between messages (an Exim client may do this if it has messages queued up
2624 for the host). Note: we do NOT reset AUTH at this point. */
2626 smtp_reset(reset_point);
2627 message_ended = END_NOTSTARTED;
2629 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2630 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2631 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2633 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2636 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2638 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2640 /* Batched SMTP is handled in a different function. */
2642 if (smtp_batched_input) return smtp_setup_batch_msg();
2644 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2645 value. The values are 2 larger than the required yield of the function. */
2650 uschar *etrn_command;
2651 uschar *etrn_serialize_key;
2653 uschar *log_msg, *smtp_code;
2654 uschar *user_msg = NULL;
2655 uschar *recipient = NULL;
2656 uschar *hello = NULL;
2657 uschar *set_id = NULL;
2659 BOOL was_rej_mail = FALSE;
2660 BOOL was_rcpt = FALSE;
2661 void (*oldsignal)(int);
2663 int start, end, sender_domain, recipient_domain;
2668 switch(smtp_read_command(TRUE))
2670 /* The AUTH command is not permitted to occur inside a transaction, and may
2671 occur successfully only once per connection. Actually, that isn't quite
2672 true. When TLS is started, all previous information about a connection must
2673 be discarded, so a new AUTH is permitted at that time.
2675 AUTH may only be used when it has been advertised. However, it seems that
2676 there are clients that send AUTH when it hasn't been advertised, some of
2677 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2678 So there's a get-out that allows this to happen.
2680 AUTH is initially labelled as a "nonmail command" so that one occurrence
2681 doesn't get counted. We change the label here so that multiple failing
2682 AUTHS will eventually hit the nonmail threshold. */
2686 authentication_failed = TRUE;
2687 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2689 if (!auth_advertised && !allow_auth_unadvertised)
2691 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2692 US"AUTH command used when not advertised");
2695 if (sender_host_authenticated != NULL)
2697 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2698 US"already authenticated");
2701 if (sender_address != NULL)
2703 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2704 US"not permitted in mail transaction");
2710 if (acl_smtp_auth != NULL)
2712 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2715 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2720 /* Find the name of the requested authentication mechanism. */
2723 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
2725 if (!isalnum(c) && c != '-' && c != '_')
2727 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2728 US"invalid character in authentication mechanism name");
2734 /* If not at the end of the line, we must be at white space. Terminate the
2735 name and move the pointer on to any data that may be present. */
2737 if (*smtp_cmd_data != 0)
2739 *smtp_cmd_data++ = 0;
2740 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
2743 /* Search for an authentication mechanism which is configured for use
2744 as a server and which has been advertised (unless, sigh, allow_auth_
2745 unadvertised is set). */
2747 for (au = auths; au != NULL; au = au->next)
2749 if (strcmpic(s, au->public_name) == 0 && au->server &&
2750 (au->advertised || allow_auth_unadvertised)) break;
2755 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2756 string_sprintf("%s authentication mechanism not supported", s));
2760 /* Run the checking code, passing the remainder of the command line as
2761 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2762 it as the only set numerical variable. The authenticator may set $auth<n>
2763 and also set other numeric variables. The $auth<n> variables are preferred
2764 nowadays; the numerical variables remain for backwards compatibility.
2766 Afterwards, have a go at expanding the set_id string, even if
2767 authentication failed - for bad passwords it can be useful to log the
2768 userid. On success, require set_id to expand and exist, and put it in
2769 authenticated_id. Save this in permanent store, as the working store gets
2770 reset at HELO, RSET, etc. */
2772 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2774 expand_nlength[0] = 0; /* $0 contains nothing */
2776 c = (au->info->servercode)(au, smtp_cmd_data);
2777 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2778 expand_nmax = -1; /* Reset numeric variables */
2779 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2781 /* The value of authenticated_id is stored in the spool file and printed in
2782 log lines. It must not contain binary zeros or newline characters. In
2783 normal use, it never will, but when playing around or testing, this error
2784 can (did) happen. To guard against this, ensure that the id contains only
2785 printing characters. */
2787 if (set_id != NULL) set_id = string_printing(set_id);
2789 /* For the non-OK cases, set up additional logging data if set_id
2794 if (set_id != NULL && *set_id != 0)
2795 set_id = string_sprintf(" (set_id=%s)", set_id);
2799 /* Switch on the result */
2804 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2806 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2807 sender_host_authenticated = au->name;
2808 authentication_failed = FALSE;
2810 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2811 ((sender_host_address != NULL)? pnlocal : 0);
2812 s = ss = US"235 Authentication succeeded";
2813 authenticated_by = au;
2817 /* Authentication succeeded, but we failed to expand the set_id string.
2818 Treat this as a temporary error. */
2820 auth_defer_msg = expand_string_message;
2824 s = string_sprintf("435 Unable to authenticate at present%s",
2825 auth_defer_user_msg);
2826 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2827 set_id, auth_defer_msg);
2831 s = ss = US"501 Invalid base64 data";
2835 s = ss = US"501 Authentication cancelled";
2839 s = ss = US"553 Initial data not expected";
2843 s = US"535 Incorrect authentication data";
2844 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2848 s = US"435 Internal error";
2849 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2850 "check", set_id, c);
2854 smtp_printf("%s\r\n", s);
2856 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2857 au->name, host_and_ident(FALSE), ss);
2859 break; /* AUTH_CMD */
2861 /* The HELO/EHLO commands are permitted to appear in the middle of a
2862 session as well as at the beginning. They have the effect of a reset in
2863 addition to their other functions. Their absence at the start cannot be
2864 taken to be an error.
2868 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2869 or 502 failure replies MUST be returned as appropriate. The SMTP
2870 server MUST stay in the same state after transmitting these replies
2871 that it was in before the EHLO was received.
2873 Therefore, we do not do the reset until after checking the command for
2874 acceptability. This change was made for Exim release 4.11. Previously
2875 it did the reset first. */
2888 HELO_EHLO: /* Common code for HELO and EHLO */
2889 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2890 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2892 /* Reject the HELO if its argument was invalid or non-existent. A
2893 successful check causes the argument to be saved in malloc store. */
2895 if (!check_helo(smtp_cmd_data))
2897 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2899 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2900 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2901 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2902 string_printing(smtp_cmd_argument));
2904 if (++synprot_error_count > smtp_max_synprot_errors)
2906 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2907 "syntax or protocol errors (last command was \"%s\")",
2908 host_and_ident(FALSE), smtp_cmd_buffer);
2915 /* If sender_host_unknown is true, we have got here via the -bs interface,
2916 not called from inetd. Otherwise, we are running an IP connection and the
2917 host address will be set. If the helo name is the primary name of this
2918 host and we haven't done a reverse lookup, force one now. If helo_required
2919 is set, ensure that the HELO name matches the actual host. If helo_verify
2920 is set, do the same check, but softly. */
2922 if (!sender_host_unknown)
2924 BOOL old_helo_verified = helo_verified;
2925 uschar *p = smtp_cmd_data;
2927 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2930 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2931 because otherwise the log can be confusing. */
2933 if (sender_host_name == NULL &&
2934 (deliver_domain = sender_helo_name, /* set $domain */
2935 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2936 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2937 (void)host_name_lookup();
2939 /* Rebuild the fullhost info to include the HELO name (and the real name
2940 if it was looked up.) */
2942 host_build_sender_fullhost(); /* Rebuild */
2943 set_process_info("handling%s incoming connection from %s",
2944 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2946 /* Verify if configured. This doesn't give much security, but it does
2947 make some people happy to be able to do it. If helo_required is set,
2948 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2949 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2950 now obsolescent, since the verification can now be requested selectively
2953 helo_verified = helo_verify_failed = FALSE;
2954 if (helo_required || helo_verify)
2956 BOOL tempfail = !smtp_verify_helo();
2961 smtp_printf("%d %s argument does not match calling host\r\n",
2962 tempfail? 451 : 550, hello);
2963 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2964 tempfail? "temporarily " : "",
2965 hello, sender_helo_name, host_and_ident(FALSE));
2966 helo_verified = old_helo_verified;
2967 break; /* End of HELO/EHLO processing */
2969 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2970 "helo_try_verify_hosts\n", hello);
2975 #ifdef EXPERIMENTAL_SPF
2976 /* set up SPF context */
2977 spf_init(sender_helo_name, sender_host_address);
2980 /* Apply an ACL check if one is defined; afterwards, recheck
2981 synchronization in case the client started sending in a delay. */
2983 if (acl_smtp_helo != NULL)
2985 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2988 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2989 sender_helo_name = NULL;
2990 host_build_sender_fullhost(); /* Rebuild */
2993 else if (!check_sync()) goto SYNC_FAILURE;
2996 /* Generate an OK reply. The default string includes the ident if present,
2997 and also the IP address if present. Reflecting back the ident is intended
2998 as a deterrent to mail forgers. For maximum efficiency, and also because
2999 some broken systems expect each response to be in a single packet, arrange
3000 that the entire reply is sent in one write(). */
3002 auth_advertised = FALSE;
3003 pipelining_advertised = FALSE;
3005 tls_advertised = FALSE;
3008 smtp_code = US"250 "; /* Default response code plus space*/
3009 if (user_msg == NULL)
3011 s = string_sprintf("%.3s %s Hello %s%s%s",
3013 smtp_active_hostname,
3014 (sender_ident == NULL)? US"" : sender_ident,
3015 (sender_ident == NULL)? US"" : US" at ",
3016 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3021 if (sender_host_address != NULL)
3023 s = string_cat(s, &size, &ptr, US" [", 2);
3024 s = string_cat(s, &size, &ptr, sender_host_address,
3025 Ustrlen(sender_host_address));
3026 s = string_cat(s, &size, &ptr, US"]", 1);
3030 /* A user-supplied EHLO greeting may not contain more than one line. Note
3031 that the code returned by smtp_message_code() includes the terminating
3032 whitespace character. */
3038 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3039 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3040 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3042 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3043 "newlines: message truncated: %s", string_printing(s));
3050 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3052 /* If we received EHLO, we must create a multiline response which includes
3053 the functions supported. */
3059 /* I'm not entirely happy with this, as an MTA is supposed to check
3060 that it has enough room to accept a message of maximum size before
3061 it sends this. However, there seems little point in not sending it.
3062 The actual size check happens later at MAIL FROM time. By postponing it
3063 till then, VRFY and EXPN can be used after EHLO when space is short. */
3065 if (thismessage_size_limit > 0)
3067 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3068 thismessage_size_limit);
3069 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3073 s = string_cat(s, &size, &ptr, smtp_code, 3);
3074 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3077 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3078 clean; if it has an 8-bit character in its hand, it just sends it. It
3079 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3080 However, some users want this option simply in order to stop MUAs
3081 mangling messages that contain top-bit-set characters. It is therefore
3082 provided as an option. */
3084 if (accept_8bitmime)
3086 s = string_cat(s, &size, &ptr, smtp_code, 3);
3087 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3090 /* Advertise ETRN if there's an ACL checking whether a host is
3091 permitted to issue it; a check is made when any host actually tries. */
3093 if (acl_smtp_etrn != NULL)
3095 s = string_cat(s, &size, &ptr, smtp_code, 3);
3096 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3099 /* Advertise EXPN if there's an ACL checking whether a host is
3100 permitted to issue it; a check is made when any host actually tries. */
3102 if (acl_smtp_expn != NULL)
3104 s = string_cat(s, &size, &ptr, smtp_code, 3);
3105 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3108 /* Exim is quite happy with pipelining, so let the other end know that
3109 it is safe to use it, unless advertising is disabled. */
3111 if (pipelining_enable &&
3112 verify_check_host(&pipelining_advertise_hosts) == OK)
3114 s = string_cat(s, &size, &ptr, smtp_code, 3);
3115 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3116 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3117 pipelining_advertised = TRUE;
3120 /* If any server authentication mechanisms are configured, advertise
3121 them if the current host is in auth_advertise_hosts. The problem with
3122 advertising always is that some clients then require users to
3123 authenticate (and aren't configurable otherwise) even though it may not
3124 be necessary (e.g. if the host is in host_accept_relay).
3126 RFC 2222 states that SASL mechanism names contain only upper case
3127 letters, so output the names in upper case, though we actually recognize
3128 them in either case in the AUTH command. */
3132 if (verify_check_host(&auth_advertise_hosts) == OK)
3136 for (au = auths; au != NULL; au = au->next)
3138 if (au->server && (au->advertise_condition == NULL ||
3139 expand_check_condition(au->advertise_condition, au->name,
3140 US"authenticator")))
3145 s = string_cat(s, &size, &ptr, smtp_code, 3);
3146 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3148 auth_advertised = TRUE;
3151 s = string_cat(s, &size, &ptr, US" ", 1);
3152 s = string_cat(s, &size, &ptr, au->public_name,
3153 Ustrlen(au->public_name));
3154 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3155 au->advertised = TRUE;
3157 else au->advertised = FALSE;
3159 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3163 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3164 if it has been included in the binary, and the host matches
3165 tls_advertise_hosts. We must *not* advertise if we are already in a
3166 secure connection. */
3169 if (tls_active < 0 &&
3170 verify_check_host(&tls_advertise_hosts) != FAIL)
3172 s = string_cat(s, &size, &ptr, smtp_code, 3);
3173 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3174 tls_advertised = TRUE;
3178 /* Finish off the multiline reply with one that is always available. */
3180 s = string_cat(s, &size, &ptr, smtp_code, 3);
3181 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3184 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3190 if (tls_active >= 0) (void)tls_write(s, ptr); else
3193 (void)fwrite(s, 1, ptr, smtp_out);
3197 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3198 memmove(cr, cr + 1, (ptr--) - (cr - s));
3199 debug_printf("SMTP>> %s", s);
3203 /* Reset the protocol and the state, abandoning any previous message. */
3205 received_protocol = (esmtp?
3207 ((sender_host_authenticated != NULL)? pauthed : 0) +
3208 ((tls_active >= 0)? pcrpted : 0)]
3210 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
3212 ((sender_host_address != NULL)? pnlocal : 0);
3214 smtp_reset(reset_point);
3216 break; /* HELO/EHLO */
3219 /* The MAIL command requires an address as an operand. All we do
3220 here is to parse it for syntactic correctness. The form "<>" is
3221 a special case which converts into an empty string. The start/end
3222 pointers in the original are not used further for this address, as
3223 it is the canonical extracted address which is all that is kept. */
3227 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3228 was_rej_mail = TRUE; /* Reset if accepted */
3229 env_mail_type_t * mail_args; /* Sanity check & validate args */
3231 if (helo_required && !helo_seen)
3233 smtp_printf("503 HELO or EHLO required\r\n");
3234 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3235 "HELO/EHLO given", host_and_ident(FALSE));
3239 if (sender_address != NULL)
3241 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3242 US"sender already given");
3246 if (smtp_cmd_data[0] == 0)
3248 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3249 US"MAIL must have an address operand");
3253 /* Check to see if the limit for messages per connection would be
3254 exceeded by accepting further messages. */
3256 if (smtp_accept_max_per_connection > 0 &&
3257 smtp_mailcmd_count > smtp_accept_max_per_connection)
3259 smtp_printf("421 too many messages in this connection\r\n");
3260 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3261 "messages in one connection", host_and_ident(TRUE));
3265 /* Reset for start of message - even if this is going to fail, we
3266 obviously need to throw away any previous data. */
3268 smtp_reset(reset_point);
3270 sender_data = recipient_data = NULL;
3272 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3276 uschar *name, *value, *end;
3277 unsigned long int size;
3278 BOOL arg_error = FALSE;
3280 if (!extract_option(&name, &value)) break;
3282 for (mail_args = env_mail_type_list;
3283 (char *)mail_args < (char *)env_mail_type_list + sizeof(env_mail_type_list);
3287 if (strcmpic(name, mail_args->name) == 0)
3290 if (mail_args->need_value && strcmpic(value, US"") == 0)
3292 /* This doesn't seem right to use
3293 if ((char *)mail_args >= (char *)env_mail_type_list + sizeof(env_mail_type_list))
3297 switch(mail_args->value)
3299 /* Handle SIZE= by reading the value. We don't do the check till later,
3300 in order to be able to log the sender address on failure. */
3301 case ENV_MAIL_OPT_SIZE:
3302 /* if (strcmpic(name, US"SIZE") == 0 && */
3303 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
3305 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3307 message_size = (int)size;
3313 /* If this session was initiated with EHLO and accept_8bitmime is set,
3314 Exim will have indicated that it supports the BODY=8BITMIME option. In
3315 fact, it does not support this according to the RFCs, in that it does not
3316 take any special action for forwarding messages containing 8-bit
3317 characters. That is why accept_8bitmime is not the default setting, but
3318 some sites want the action that is provided. We recognize both "8BITMIME"
3319 and "7BIT" as body types, but take no action. */
3320 case ENV_MAIL_OPT_BODY:
3321 if (accept_8bitmime &&
3322 (strcmpic(value, US"8BITMIME") == 0 ||
3323 strcmpic(value, US"7BIT") == 0) )
3328 /* Handle the AUTH extension. If the value given is not "<>" and either
3329 the ACL says "yes" or there is no ACL but the sending host is
3330 authenticated, we set it up as the authenticated sender. However, if the
3331 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3332 the condition is met. The value of AUTH is an xtext, which means that +,
3333 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3335 case ENV_MAIL_OPT_AUTH:
3336 if (Ustrcmp(value, "<>") != 0)
3341 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3343 /* Put back terminator overrides for error message */
3346 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3347 US"invalid data for AUTH");
3350 if (acl_smtp_mailauth == NULL)
3352 ignore_msg = US"client not authenticated";
3353 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3357 ignore_msg = US"rejected by ACL";
3358 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3359 &user_msg, &log_msg);
3365 if (authenticated_by == NULL ||
3366 authenticated_by->mail_auth_condition == NULL ||
3367 expand_check_condition(authenticated_by->mail_auth_condition,
3368 authenticated_by->name, US"authenticator"))
3369 break; /* Accept the AUTH */
3371 ignore_msg = US"server_mail_auth_condition failed";
3372 if (authenticated_id != NULL)
3373 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3374 ignore_msg, authenticated_id);
3379 authenticated_sender = NULL;
3380 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3381 value, host_and_ident(TRUE), ignore_msg);
3384 /* Should only get DEFER or ERROR here. Put back terminator
3385 overrides for error message */
3390 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3397 /* Unknown option. Stick back the terminator characters and break
3398 the loop. An error for a malformed address will occur. */
3401 /* BAD_MAIL_ARGS: */
3406 /* Break out of for loop if switch() had bad argument or
3407 when start of the email address is reached */
3408 if (arg_error) break;
3411 /* If we have passed the threshold for rate limiting, apply the current
3412 delay, and update it for next time, provided this is a limited host. */
3414 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3415 verify_check_host(&smtp_ratelimit_hosts) == OK)
3417 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3418 smtp_delay_mail/1000.0);
3419 millisleep((int)smtp_delay_mail);
3420 smtp_delay_mail *= smtp_rlm_factor;
3421 if (smtp_delay_mail > (double)smtp_rlm_limit)
3422 smtp_delay_mail = (double)smtp_rlm_limit;
3425 /* Now extract the address, first applying any SMTP-time rewriting. The
3426 TRUE flag allows "<>" as a sender address. */
3428 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3429 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3430 global_rewrite_rules) : smtp_cmd_data;
3432 /* rfc821_domains = TRUE; << no longer needed */
3434 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3436 /* rfc821_domains = FALSE; << no longer needed */
3438 if (raw_sender == NULL)
3440 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3444 sender_address = raw_sender;
3446 /* If there is a configured size limit for mail, check that this message
3447 doesn't exceed it. The check is postponed to this point so that the sender
3450 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3452 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3453 log_write(L_size_reject,
3454 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3455 "message too big: size%s=%d max=%d",
3457 host_and_ident(TRUE),
3458 (message_size == INT_MAX)? ">" : "",
3460 thismessage_size_limit);
3461 sender_address = NULL;
3465 /* Check there is enough space on the disk unless configured not to.
3466 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3467 plus the current message - i.e. we accept the message only if it won't
3468 reduce the space below the threshold. Add 5000 to the size to allow for
3469 overheads such as the Received: line and storing of recipients, etc.
3470 By putting the check here, even when SIZE is not given, it allow VRFY
3471 and EXPN etc. to be used when space is short. */
3473 if (!receive_check_fs(
3474 (smtp_check_spool_space && message_size >= 0)?
3475 message_size + 5000 : 0))
3477 smtp_printf("452 Space shortage, please try later\r\n");
3478 sender_address = NULL;
3482 /* If sender_address is unqualified, reject it, unless this is a locally
3483 generated message, or the sending host or net is permitted to send
3484 unqualified addresses - typically local machines behaving as MUAs -
3485 in which case just qualify the address. The flag is set above at the start
3486 of the SMTP connection. */
3488 if (sender_domain == 0 && sender_address[0] != 0)
3490 if (allow_unqualified_sender)
3492 sender_domain = Ustrlen(sender_address) + 1;
3493 sender_address = rewrite_address_qualify(sender_address, FALSE);
3494 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3499 smtp_printf("501 %s: sender address must contain a domain\r\n",
3501 log_write(L_smtp_syntax_error,
3502 LOG_MAIN|LOG_REJECT,
3503 "unqualified sender rejected: <%s> %s%s",
3505 host_and_ident(TRUE),
3507 sender_address = NULL;
3512 /* Apply an ACL check if one is defined, before responding. Afterwards,
3513 when pipelining is not advertised, do another sync check in case the ACL
3514 delayed and the client started sending in the meantime. */
3516 if (acl_smtp_mail == NULL) rc = OK; else
3518 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3519 if (rc == OK && !pipelining_advertised && !check_sync())
3523 if (rc == OK || rc == DISCARD)
3525 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3526 else smtp_user_msg(US"250", user_msg);
3527 smtp_delay_rcpt = smtp_rlr_base;
3528 recipients_discarded = (rc == DISCARD);
3529 was_rej_mail = FALSE;
3533 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3534 sender_address = NULL;
3539 /* The RCPT command requires an address as an operand. There may be any
3540 number of RCPT commands, specifying multiple recipients. We build them all
3541 into a data structure. The start/end values given by parse_extract_address
3542 are not used, as we keep only the extracted address. */
3547 was_rcpt = rcpt_in_progress = TRUE;
3549 /* There must be a sender address; if the sender was rejected and
3550 pipelining was advertised, we assume the client was pipelining, and do not
3551 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3552 get the same treatment. */
3554 if (sender_address == NULL)
3556 if (pipelining_advertised && last_was_rej_mail)
3558 smtp_printf("503 sender not yet given\r\n");
3559 was_rej_mail = TRUE;
3563 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3564 US"sender not yet given");
3565 was_rcpt = FALSE; /* Not a valid RCPT */
3571 /* Check for an operand */
3573 if (smtp_cmd_data[0] == 0)
3575 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3576 US"RCPT must have an address operand");
3581 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3582 as a recipient address */
3584 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3585 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3586 global_rewrite_rules) : smtp_cmd_data;
3588 /* rfc821_domains = TRUE; << no longer needed */
3589 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3590 &recipient_domain, FALSE);
3591 /* rfc821_domains = FALSE; << no longer needed */
3593 if (recipient == NULL)
3595 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3600 /* If the recipient address is unqualified, reject it, unless this is a
3601 locally generated message. However, unqualified addresses are permitted
3602 from a configured list of hosts and nets - typically when behaving as
3603 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3604 really. The flag is set at the start of the SMTP connection.
3606 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3607 assumed this meant "reserved local part", but the revision of RFC 821 and
3608 friends now makes it absolutely clear that it means *mailbox*. Consequently
3609 we must always qualify this address, regardless. */
3611 if (recipient_domain == 0)
3613 if (allow_unqualified_recipient ||
3614 strcmpic(recipient, US"postmaster") == 0)
3616 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3618 recipient_domain = Ustrlen(recipient) + 1;
3619 recipient = rewrite_address_qualify(recipient, TRUE);
3624 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3626 log_write(L_smtp_syntax_error,
3627 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3628 "<%s> %s%s", recipient, host_and_ident(TRUE),
3634 /* Check maximum allowed */
3636 if (rcpt_count > recipients_max && recipients_max > 0)
3638 if (recipients_max_reject)
3641 smtp_printf("552 too many recipients\r\n");
3643 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3644 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3649 smtp_printf("452 too many recipients\r\n");
3651 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3652 "temporarily rejected: sender=<%s> %s", sender_address,
3653 host_and_ident(TRUE));
3660 /* If we have passed the threshold for rate limiting, apply the current
3661 delay, and update it for next time, provided this is a limited host. */
3663 if (rcpt_count > smtp_rlr_threshold &&
3664 verify_check_host(&smtp_ratelimit_hosts) == OK)
3666 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3667 smtp_delay_rcpt/1000.0);
3668 millisleep((int)smtp_delay_rcpt);
3669 smtp_delay_rcpt *= smtp_rlr_factor;
3670 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3671 smtp_delay_rcpt = (double)smtp_rlr_limit;
3674 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3675 for them. Otherwise, check the access control list for this recipient. As
3676 there may be a delay in this, re-check for a synchronization error
3677 afterwards, unless pipelining was advertised. */
3679 if (recipients_discarded) rc = DISCARD; else
3681 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
3683 if (rc == OK && !pipelining_advertised && !check_sync())
3687 /* The ACL was happy */
3691 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3692 else smtp_user_msg(US"250", user_msg);
3693 receive_add_recipient(recipient, -1);
3696 /* The recipient was discarded */
3698 else if (rc == DISCARD)
3700 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3701 else smtp_user_msg(US"250", user_msg);
3704 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3705 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3706 (sender_address_unrewritten != NULL)?
3707 sender_address_unrewritten : sender_address,
3708 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3709 (log_msg == NULL)? US"" : US": ",
3710 (log_msg == NULL)? US"" : log_msg);
3713 /* Either the ACL failed the address, or it was deferred. */
3717 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3718 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3723 /* The DATA command is legal only if it follows successful MAIL FROM
3724 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3725 not counted as a protocol error if it follows RCPT (which must have been
3726 rejected if there are no recipients.) This function is complete when a
3727 valid DATA command is encountered.
3729 Note concerning the code used: RFC 2821 says this:
3731 - If there was no MAIL, or no RCPT, command, or all such commands
3732 were rejected, the server MAY return a "command out of sequence"
3733 (503) or "no valid recipients" (554) reply in response to the
3736 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3737 because it is the same whether pipelining is in use or not.
3739 If all the RCPT commands that precede DATA provoked the same error message
3740 (often indicating some kind of system error), it is helpful to include it
3741 with the DATA rejection (an idea suggested by Tony Finch). */
3745 if (!discarded && recipients_count <= 0)
3747 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
3749 uschar *code = US"503";
3750 int len = Ustrlen(rcpt_smtp_response);
3751 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
3753 /* Responses from smtp_printf() will have \r\n on the end */
3754 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
3755 rcpt_smtp_response[len-2] = 0;
3756 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
3758 if (pipelining_advertised && last_was_rcpt)
3759 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
3761 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3762 US"valid RCPT command must precede DATA");
3766 if (toomany && recipients_max_reject)
3768 sender_address = NULL; /* This will allow a new MAIL without RSET */
3769 sender_address_unrewritten = NULL;
3770 smtp_printf("554 Too many recipients\r\n");
3774 /* If there is an ACL, re-check the synchronization afterwards, since the
3775 ACL may have delayed. */
3777 if (acl_smtp_predata == NULL) rc = OK; else
3779 enable_dollar_recipients = TRUE;
3780 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
3782 enable_dollar_recipients = FALSE;
3783 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
3788 if (user_msg == NULL)
3789 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3790 else smtp_user_msg(US"354", user_msg);
3792 message_ended = END_NOTENDED; /* Indicate in middle of data */
3795 /* Either the ACL failed the address, or it was deferred. */
3798 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3804 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3806 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3812 /* rfc821_domains = TRUE; << no longer needed */
3813 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
3814 &recipient_domain, FALSE);
3815 /* rfc821_domains = FALSE; << no longer needed */
3817 if (address == NULL)
3818 s = string_sprintf("501 %s", errmess);
3821 address_item *addr = deliver_make_addr(address, FALSE);
3822 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3823 -1, -1, NULL, NULL, NULL))
3826 s = string_sprintf("250 <%s> is deliverable", address);
3830 s = (addr->user_message != NULL)?
3831 string_sprintf("451 <%s> %s", address, addr->user_message) :
3832 string_sprintf("451 Cannot resolve <%s> at this time", address);
3836 s = (addr->user_message != NULL)?
3837 string_sprintf("550 <%s> %s", address, addr->user_message) :
3838 string_sprintf("550 <%s> is not deliverable", address);
3839 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3840 smtp_cmd_argument, host_and_ident(TRUE));
3845 smtp_printf("%s\r\n", s);
3852 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3854 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3857 BOOL save_log_testing_mode = log_testing_mode;
3858 address_test_mode = log_testing_mode = TRUE;
3859 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
3860 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3862 address_test_mode = FALSE;
3863 log_testing_mode = save_log_testing_mode; /* true for -bh */
3872 if (!tls_advertised)
3874 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3875 US"STARTTLS command used when not advertised");
3879 /* Apply an ACL check if one is defined */
3881 if (acl_smtp_starttls != NULL)
3883 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3887 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3892 /* RFC 2487 is not clear on when this command may be sent, though it
3893 does state that all information previously obtained from the client
3894 must be discarded if a TLS session is started. It seems reasonble to
3895 do an implied RSET when STARTTLS is received. */
3897 incomplete_transaction_log(US"STARTTLS");
3898 smtp_reset(reset_point);
3900 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3902 /* There's an attack where more data is read in past the STARTTLS command
3903 before TLS is negotiated, then assumed to be part of the secure session
3904 when used afterwards; we use segregated input buffers, so are not
3905 vulnerable, but we want to note when it happens and, for sheer paranoia,
3906 ensure that the buffer is "wiped".
3907 Pipelining sync checks will normally have protected us too, unless disabled
3908 by configuration. */
3910 if (receive_smtp_buffered())
3913 debug_printf("Non-empty input buffer after STARTTLS; naive attack?");
3915 smtp_inend = smtp_inptr = smtp_inbuffer;
3916 /* and if TLS is already active, tls_server_start() should fail */
3919 /* There is nothing we value in the input buffer and if TLS is succesfully
3920 negotiated, we won't use this buffer again; if TLS fails, we'll just read
3921 fresh content into it. The buffer contains arbitrary content from an
3922 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
3923 It seems safest to just wipe away the content rather than leave it as a
3924 target to jump to. */
3926 memset(smtp_inbuffer, 0, in_buffer_size);
3928 /* Attempt to start up a TLS session, and if successful, discard all
3929 knowledge that was obtained previously. At least, that's what the RFC says,
3930 and that's what happens by default. However, in order to work round YAEB,
3931 there is an option to remember the esmtp state. Sigh.
3933 We must allow for an extra EHLO command and an extra AUTH command after
3934 STARTTLS that don't add to the nonmail command count. */
3936 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3938 if (!tls_remember_esmtp)
3939 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3940 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3941 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3942 if (sender_helo_name != NULL)
3944 store_free(sender_helo_name);
3945 sender_helo_name = NULL;
3946 host_build_sender_fullhost(); /* Rebuild */
3947 set_process_info("handling incoming TLS connection from %s",
3948 host_and_ident(FALSE));
3950 received_protocol = (esmtp?
3951 protocols[pextend + pcrpted +
3952 ((sender_host_authenticated != NULL)? pauthed : 0)]
3954 protocols[pnormal + pcrpted])
3956 ((sender_host_address != NULL)? pnlocal : 0);
3958 sender_host_authenticated = NULL;
3959 authenticated_id = NULL;
3960 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3961 DEBUG(D_tls) debug_printf("TLS active\n");
3962 break; /* Successful STARTTLS */
3965 /* Some local configuration problem was discovered before actually trying
3966 to do a TLS handshake; give a temporary error. */
3968 else if (rc == DEFER)
3970 smtp_printf("454 TLS currently unavailable\r\n");
3974 /* Hard failure. Reject everything except QUIT or closed connection. One
3975 cause for failure is a nested STARTTLS, in which case tls_active remains
3976 set, but we must still reject all incoming commands. */
3978 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3981 switch(smtp_read_command(FALSE))
3984 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3985 smtp_get_connection_info());
3986 smtp_notquit_exit(US"tls-failed", NULL, NULL);
3990 /* It is perhaps arguable as to which exit ACL should be called here,
3991 but as it is probably a situtation that almost never arises, it
3992 probably doesn't matter. We choose to call the real QUIT ACL, which in
3993 some sense is perhaps "right". */
3997 if (acl_smtp_quit != NULL)
3999 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
4002 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4005 if (user_msg == NULL)
4006 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4008 smtp_respond(US"221", 3, TRUE, user_msg);
4009 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4010 smtp_get_connection_info());
4015 smtp_printf("554 Security failure\r\n");
4024 /* The ACL for QUIT is provided for gathering statistical information or
4025 similar; it does not affect the response code, but it can supply a custom
4030 incomplete_transaction_log(US"QUIT");
4031 if (acl_smtp_quit != NULL)
4033 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
4035 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4038 if (user_msg == NULL)
4039 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4041 smtp_respond(US"221", 3, TRUE, user_msg);
4048 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4049 smtp_get_connection_info());
4055 incomplete_transaction_log(US"RSET");
4056 smtp_reset(reset_point);
4058 smtp_printf("250 Reset OK\r\n");
4059 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
4065 smtp_printf("250 OK\r\n");
4069 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
4070 used, a check will be done for permitted hosts. Show STARTTLS only if not
4071 already in a TLS session and if it would be advertised in the EHLO
4076 smtp_printf("214-Commands supported:\r\n");
4080 Ustrcat(buffer, " AUTH");
4082 if (tls_active < 0 &&
4083 verify_check_host(&tls_advertise_hosts) != FAIL)
4084 Ustrcat(buffer, " STARTTLS");
4086 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
4087 Ustrcat(buffer, " NOOP QUIT RSET HELP");
4088 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4089 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4090 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4091 smtp_printf("214%s\r\n", buffer);
4097 incomplete_transaction_log(US"connection lost");
4098 smtp_notquit_exit(US"connection-lost", US"421",
4099 US"%s lost input connection", smtp_active_hostname);
4101 /* Don't log by default unless in the middle of a message, as some mailers
4102 just drop the call rather than sending QUIT, and it clutters up the logs.
4105 if (sender_address != NULL || recipients_count > 0)
4106 log_write(L_lost_incoming_connection,
4108 "unexpected %s while reading SMTP command from %s%s",
4109 sender_host_unknown? "EOF" : "disconnection",
4110 host_and_ident(FALSE), smtp_read_error);
4112 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4113 smtp_get_connection_info(), smtp_read_error);
4121 if (sender_address != NULL)
4123 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4124 US"ETRN is not permitted inside a transaction");
4128 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4129 host_and_ident(FALSE));
4131 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4134 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4138 /* Compute the serialization key for this command. */
4140 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4142 /* If a command has been specified for running as a result of ETRN, we
4143 permit any argument to ETRN. If not, only the # standard form is permitted,
4144 since that is strictly the only kind of ETRN that can be implemented
4145 according to the RFC. */
4147 if (smtp_etrn_command != NULL)
4151 etrn_command = smtp_etrn_command;
4152 deliver_domain = smtp_cmd_data;
4153 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4154 US"ETRN processing", &error);
4155 deliver_domain = NULL;
4158 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4160 smtp_printf("458 Internal failure\r\n");
4165 /* Else set up to call Exim with the -R option. */
4169 if (*smtp_cmd_data++ != '#')
4171 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4172 US"argument must begin with #");
4175 etrn_command = US"exim -R";
4176 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4180 /* If we are host-testing, don't actually do anything. */
4186 debug_printf("ETRN command is: %s\n", etrn_command);
4187 debug_printf("ETRN command execution skipped\n");
4189 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4190 else smtp_user_msg(US"250", user_msg);
4195 /* If ETRN queue runs are to be serialized, check the database to
4196 ensure one isn't already running. */
4198 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4200 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4204 /* Fork a child process and run the command. We don't want to have to
4205 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4206 forking. It should be set that way anyway for external incoming SMTP,
4207 but we save and restore to be tidy. If serialization is required, we
4208 actually run the command in yet another process, so we can wait for it
4209 to complete and then remove the serialization lock. */
4211 oldsignal = signal(SIGCHLD, SIG_IGN);
4213 if ((pid = fork()) == 0)
4215 smtp_input = FALSE; /* This process is not associated with the */
4216 (void)fclose(smtp_in); /* SMTP call any more. */
4217 (void)fclose(smtp_out);
4219 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
4221 /* If not serializing, do the exec right away. Otherwise, fork down
4222 into another process. */
4224 if (!smtp_etrn_serialize || (pid = fork()) == 0)
4226 DEBUG(D_exec) debug_print_argv(argv);
4227 exim_nullstd(); /* Ensure std{in,out,err} exist */
4228 execv(CS argv[0], (char *const *)argv);
4229 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
4230 etrn_command, strerror(errno));
4231 _exit(EXIT_FAILURE); /* paranoia */
4234 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4235 is, we are in the first subprocess, after forking again. All we can do
4236 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4237 complete, before removing the serialization. */
4240 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4241 "failed: %s", strerror(errno));
4245 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4247 (void)wait(&status);
4248 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4252 enq_end(etrn_serialize_key);
4253 _exit(EXIT_SUCCESS);
4256 /* Back in the top level SMTP process. Check that we started a subprocess
4257 and restore the signal state. */
4261 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4263 smtp_printf("458 Unable to fork process\r\n");
4264 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4268 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4269 else smtp_user_msg(US"250", user_msg);
4272 signal(SIGCHLD, oldsignal);
4277 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4278 US"unexpected argument data");
4282 /* This currently happens only for NULLs, but could be extended. */
4285 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
4286 US"NULL character(s) present (shown as '?')");
4287 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
4293 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
4294 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
4295 c = smtp_inend - smtp_inptr;
4296 if (c > 150) c = 150;
4298 incomplete_transaction_log(US"sync failure");
4299 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
4300 "(next input sent too soon: pipelining was%s advertised): "
4301 "rejected \"%s\" %s next input=\"%s\"",
4302 pipelining_advertised? "" : " not",
4303 smtp_cmd_buffer, host_and_ident(TRUE),
4304 string_printing(smtp_inptr));
4305 smtp_notquit_exit(US"synchronization-error", US"554",
4306 US"SMTP synchronization error");
4307 done = 1; /* Pretend eof - drops connection */
4311 case TOO_MANY_NONMAIL_CMD:
4312 s = smtp_cmd_buffer;
4313 while (*s != 0 && !isspace(*s)) s++;
4314 incomplete_transaction_log(US"too many non-mail commands");
4315 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4316 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
4317 s - smtp_cmd_buffer, smtp_cmd_buffer);
4318 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
4319 done = 1; /* Pretend eof - drops connection */
4324 if (unknown_command_count++ >= smtp_max_unknown_commands)
4326 log_write(L_smtp_syntax_error, LOG_MAIN,
4327 "SMTP syntax error in \"%s\" %s %s",
4328 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
4329 US"unrecognized command");
4330 incomplete_transaction_log(US"unrecognized command");
4331 smtp_notquit_exit(US"bad-commands", US"500",
4332 US"Too many unrecognized commands");
4334 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4335 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
4339 done = synprot_error(L_smtp_syntax_error, 500, NULL,
4340 US"unrecognized command");
4344 /* This label is used by goto's inside loops that want to break out to
4345 the end of the command-processing loop. */
4348 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
4349 last_was_rcpt = was_rcpt; /* protocol error handling */
4353 return done - 2; /* Convert yield values */
4356 /* End of smtp_in.c */