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 cancel_cutthrough_connection();
1040 message_linecount = 0;
1042 acl_added_headers = NULL;
1043 queue_only_policy = FALSE;
1044 rcpt_smtp_response = NULL;
1045 rcpt_smtp_response_same = TRUE;
1046 rcpt_in_progress = FALSE;
1047 deliver_freeze = FALSE; /* Can be set by ACL */
1048 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1049 fake_response = OK; /* Can be set by ACL */
1050 #ifdef WITH_CONTENT_SCAN
1051 no_mbox_unspool = FALSE; /* Can be set by ACL */
1053 submission_mode = FALSE; /* Can be set by ACL */
1054 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1055 active_local_from_check = local_from_check; /* Can be set by ACL */
1056 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1057 sender_address = NULL;
1058 submission_name = NULL; /* Can be set by ACL */
1059 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1060 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1061 sender_verified_list = NULL; /* No senders verified */
1062 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1063 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1064 authenticated_sender = NULL;
1065 #ifdef EXPERIMENTAL_BRIGHTMAIL
1067 bmi_verdicts = NULL;
1069 #ifndef DISABLE_DKIM
1070 dkim_signers = NULL;
1071 dkim_disable_verify = FALSE;
1072 dkim_collect_input = FALSE;
1074 #ifdef EXPERIMENTAL_SPF
1075 spf_header_comment = NULL;
1076 spf_received = NULL;
1078 spf_smtp_comment = NULL;
1080 body_linecount = body_zerocount = 0;
1082 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1083 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1084 /* Note that ratelimiters_conn persists across resets. */
1086 /* Reset message ACL variables */
1090 /* The message body variables use malloc store. They may be set if this is
1091 not the first message in an SMTP session and the previous message caused them
1092 to be referenced in an ACL. */
1094 if (message_body != NULL)
1096 store_free(message_body);
1097 message_body = NULL;
1100 if (message_body_end != NULL)
1102 store_free(message_body_end);
1103 message_body_end = NULL;
1106 /* Warning log messages are also saved in malloc store. They are saved to avoid
1107 repetition in the same message, but it seems right to repeat them for different
1110 while (acl_warn_logged != NULL)
1112 string_item *this = acl_warn_logged;
1113 acl_warn_logged = acl_warn_logged->next;
1122 /*************************************************
1123 * Initialize for incoming batched SMTP message *
1124 *************************************************/
1126 /* This function is called from smtp_setup_msg() in the case when
1127 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1128 of messages in one file with SMTP commands between them. All errors must be
1129 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1130 relevant. After an error on a sender, or an invalid recipient, the remainder
1131 of the message is skipped. The value of received_protocol is already set.
1134 Returns: > 0 message successfully started (reached DATA)
1135 = 0 QUIT read or end of file reached
1136 < 0 should not occur
1140 smtp_setup_batch_msg(void)
1143 void *reset_point = store_get(0);
1145 /* Save the line count at the start of each transaction - single commands
1146 like HELO and RSET count as whole transactions. */
1148 bsmtp_transaction_linecount = receive_linecount;
1150 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1152 smtp_reset(reset_point); /* Reset for start of message */
1154 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1155 value. The values are 2 larger than the required yield of the function. */
1160 uschar *recipient = NULL;
1161 int start, end, sender_domain, recipient_domain;
1163 switch(smtp_read_command(FALSE))
1165 /* The HELO/EHLO commands set sender_address_helo if they have
1166 valid data; otherwise they are ignored, except that they do
1167 a reset of the state. */
1172 check_helo(smtp_cmd_data);
1176 smtp_reset(reset_point);
1177 bsmtp_transaction_linecount = receive_linecount;
1181 /* The MAIL FROM command requires an address as an operand. All we
1182 do here is to parse it for syntactic correctness. The form "<>" is
1183 a special case which converts into an empty string. The start/end
1184 pointers in the original are not used further for this address, as
1185 it is the canonical extracted address which is all that is kept. */
1188 if (sender_address != NULL)
1189 /* The function moan_smtp_batch() does not return. */
1190 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1192 if (smtp_cmd_data[0] == 0)
1193 /* The function moan_smtp_batch() does not return. */
1194 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1196 /* Reset to start of message */
1198 smtp_reset(reset_point);
1200 /* Apply SMTP rewrite */
1202 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1203 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1204 US"", global_rewrite_rules) : smtp_cmd_data;
1206 /* Extract the address; the TRUE flag allows <> as valid */
1209 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1212 if (raw_sender == NULL)
1213 /* The function moan_smtp_batch() does not return. */
1214 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1216 sender_address = string_copy(raw_sender);
1218 /* Qualify unqualified sender addresses if permitted to do so. */
1220 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1222 if (allow_unqualified_sender)
1224 sender_address = rewrite_address_qualify(sender_address, FALSE);
1225 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1226 "and rewritten\n", raw_sender);
1228 /* The function moan_smtp_batch() does not return. */
1229 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1235 /* The RCPT TO command requires an address as an operand. All we do
1236 here is to parse it for syntactic correctness. There may be any number
1237 of RCPT TO commands, specifying multiple senders. We build them all into
1238 a data structure that is in argc/argv format. The start/end values
1239 given by parse_extract_address are not used, as we keep only the
1240 extracted address. */
1243 if (sender_address == NULL)
1244 /* The function moan_smtp_batch() does not return. */
1245 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1247 if (smtp_cmd_data[0] == 0)
1248 /* The function moan_smtp_batch() does not return. */
1249 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1251 /* Check maximum number allowed */
1253 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1254 /* The function moan_smtp_batch() does not return. */
1255 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1256 recipients_max_reject? "552": "452");
1258 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1259 recipient address */
1261 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
1262 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1263 global_rewrite_rules) : smtp_cmd_data;
1265 /* rfc821_domains = TRUE; << no longer needed */
1266 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1267 &recipient_domain, FALSE);
1268 /* rfc821_domains = FALSE; << no longer needed */
1270 if (recipient == NULL)
1271 /* The function moan_smtp_batch() does not return. */
1272 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1274 /* If the recipient address is unqualified, qualify it if permitted. Then
1275 add it to the list of recipients. */
1277 if (recipient_domain == 0)
1279 if (allow_unqualified_recipient)
1281 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1283 recipient = rewrite_address_qualify(recipient, TRUE);
1285 /* The function moan_smtp_batch() does not return. */
1286 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1289 receive_add_recipient(recipient, -1);
1293 /* The DATA command is legal only if it follows successful MAIL FROM
1294 and RCPT TO commands. This function is complete when a valid DATA
1295 command is encountered. */
1298 if (sender_address == NULL || recipients_count <= 0)
1300 /* The function moan_smtp_batch() does not return. */
1301 if (sender_address == NULL)
1302 moan_smtp_batch(smtp_cmd_buffer,
1303 "503 MAIL FROM:<sender> command must precede DATA");
1305 moan_smtp_batch(smtp_cmd_buffer,
1306 "503 RCPT TO:<recipient> must precede DATA");
1310 done = 3; /* DATA successfully achieved */
1311 message_ended = END_NOTENDED; /* Indicate in middle of message */
1316 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1323 bsmtp_transaction_linecount = receive_linecount;
1334 /* The function moan_smtp_batch() does not return. */
1335 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1340 /* The function moan_smtp_batch() does not return. */
1341 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1346 /* The function moan_smtp_batch() does not return. */
1347 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1352 return done - 2; /* Convert yield values */
1358 /*************************************************
1359 * Start an SMTP session *
1360 *************************************************/
1362 /* This function is called at the start of an SMTP session. Thereafter,
1363 smtp_setup_msg() is called to initiate each separate message. This
1364 function does host-specific testing, and outputs the banner line.
1367 Returns: FALSE if the session can not continue; something has
1368 gone wrong, or the connection to the host is blocked
1372 smtp_start_session(void)
1376 uschar *user_msg, *log_msg;
1380 smtp_connection_start = time(NULL);
1381 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
1382 smtp_connection_had[smtp_ch_index] = SCH_NONE;
1385 /* Default values for certain variables */
1387 helo_seen = esmtp = helo_accept_junk = FALSE;
1388 smtp_mailcmd_count = 0;
1389 count_nonmail = TRUE_UNSET;
1390 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
1391 smtp_delay_mail = smtp_rlm_base;
1392 auth_advertised = FALSE;
1393 pipelining_advertised = FALSE;
1394 pipelining_enable = TRUE;
1395 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
1396 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
1398 memset(sender_host_cache, 0, sizeof(sender_host_cache));
1400 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
1401 authentication settings from -oMaa to remain in force. */
1403 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
1404 authenticated_by = NULL;
1407 tls_cipher = tls_peerdn = NULL;
1408 tls_advertised = FALSE;
1411 /* Reset ACL connection variables */
1415 /* Allow for trailing 0 in the command and data buffers. */
1417 smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
1418 if (smtp_cmd_buffer == NULL)
1419 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1420 "malloc() failed for SMTP command buffer");
1421 smtp_cmd_buffer[0] = 0;
1422 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
1424 /* For batched input, the protocol setting can be overridden from the
1425 command line by a trusted caller. */
1427 if (smtp_batched_input)
1429 if (received_protocol == NULL) received_protocol = US"local-bsmtp";
1432 /* For non-batched SMTP input, the protocol setting is forced here. It will be
1433 reset later if any of EHLO/AUTH/STARTTLS are received. */
1437 protocols[pnormal] + ((sender_host_address != NULL)? pnlocal : 0);
1439 /* Set up the buffer for inputting using direct read() calls, and arrange to
1440 call the local functions instead of the standard C ones. */
1442 smtp_inbuffer = (uschar *)malloc(in_buffer_size);
1443 if (smtp_inbuffer == NULL)
1444 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
1445 receive_getc = smtp_getc;
1446 receive_ungetc = smtp_ungetc;
1447 receive_feof = smtp_feof;
1448 receive_ferror = smtp_ferror;
1449 receive_smtp_buffered = smtp_buffered;
1450 smtp_inptr = smtp_inend = smtp_inbuffer;
1451 smtp_had_eof = smtp_had_error = 0;
1453 /* Set up the message size limit; this may be host-specific */
1455 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
1456 if (expand_string_message != NULL)
1458 if (thismessage_size_limit == -1)
1459 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
1460 "%s", expand_string_message);
1462 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
1463 "%s", expand_string_message);
1464 smtp_closedown(US"Temporary local problem - please try later");
1468 /* When a message is input locally via the -bs or -bS options, sender_host_
1469 unknown is set unless -oMa was used to force an IP address, in which case it
1470 is checked like a real remote connection. When -bs is used from inetd, this
1471 flag is not set, causing the sending host to be checked. The code that deals
1472 with IP source routing (if configured) is never required for -bs or -bS and
1473 the flag sender_host_notsocket is used to suppress it.
1475 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
1476 reserve for certain hosts and/or networks. */
1478 if (!sender_host_unknown)
1481 BOOL reserved_host = FALSE;
1483 /* Look up IP options (source routing info) on the socket if this is not an
1484 -oMa "host", and if any are found, log them and drop the connection.
1486 Linux (and others now, see below) is different to everyone else, so there
1487 has to be some conditional compilation here. Versions of Linux before 2.1.15
1488 used a structure whose name was "options". Somebody finally realized that
1489 this name was silly, and it got changed to "ip_options". I use the
1490 newer name here, but there is a fudge in the script that sets up os.h
1491 to define a macro in older Linux systems.
1493 Sigh. Linux is a fast-moving target. Another generation of Linux uses
1494 glibc 2, which has chosen ip_opts for the structure name. This is now
1495 really a glibc thing rather than a Linux thing, so the condition name
1496 has been changed to reflect this. It is relevant also to GNU/Hurd.
1498 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
1499 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
1500 a special macro defined in the os.h file.
1502 Some DGUX versions on older hardware appear not to support IP options at
1503 all, so there is now a general macro which can be set to cut out this
1506 How to do this properly in IPv6 is not yet known. */
1508 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
1510 #ifdef GLIBC_IP_OPTIONS
1511 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
1516 #elif defined DARWIN_IP_OPTIONS
1522 if (!host_checking && !sender_host_notsocket)
1525 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
1526 struct ip_options *ipopt = store_get(optlen);
1528 struct ip_opts ipoptblock;
1529 struct ip_opts *ipopt = &ipoptblock;
1530 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1532 struct ipoption ipoptblock;
1533 struct ipoption *ipopt = &ipoptblock;
1534 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
1537 /* Occasional genuine failures of getsockopt() have been seen - for
1538 example, "reset by peer". Therefore, just log and give up on this
1539 call, unless the error is ENOPROTOOPT. This error is given by systems
1540 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
1541 of writing. So for that error, carry on - we just can't do an IP options
1544 DEBUG(D_receive) debug_printf("checking for IP options\n");
1546 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
1549 if (errno != ENOPROTOOPT)
1551 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
1552 host_and_ident(FALSE), strerror(errno));
1553 smtp_printf("451 SMTP service not available\r\n");
1558 /* Deal with any IP options that are set. On the systems I have looked at,
1559 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
1560 more logging data than will fit in big_buffer. Nevertheless, after somebody
1561 questioned this code, I've added in some paranoid checking. */
1563 else if (optlen > 0)
1565 uschar *p = big_buffer;
1566 uschar *pend = big_buffer + big_buffer_size;
1567 uschar *opt, *adptr;
1569 struct in_addr addr;
1572 uschar *optstart = (uschar *)(ipopt->__data);
1574 uschar *optstart = (uschar *)(ipopt->ip_opts);
1576 uschar *optstart = (uschar *)(ipopt->ipopt_list);
1579 DEBUG(D_receive) debug_printf("IP options exist\n");
1581 Ustrcpy(p, "IP options on incoming call:");
1584 for (opt = optstart; opt != NULL &&
1585 opt < (uschar *)(ipopt) + optlen;)
1599 if (!string_format(p, pend-p, " %s [@%s",
1600 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
1602 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
1604 inet_ntoa(ipopt->ip_dst)))
1606 inet_ntoa(ipopt->ipopt_dst)))
1614 optcount = (opt[1] - 3) / sizeof(struct in_addr);
1616 while (optcount-- > 0)
1618 memcpy(&addr, adptr, sizeof(addr));
1619 if (!string_format(p, pend - p - 1, "%s%s",
1620 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
1626 adptr += sizeof(struct in_addr);
1635 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
1638 for (i = 0; i < opt[1]; i++)
1640 sprintf(CS p, "%2.2x ", opt[i]);
1651 log_write(0, LOG_MAIN, "%s", big_buffer);
1653 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
1655 log_write(0, LOG_MAIN|LOG_REJECT,
1656 "connection from %s refused (IP options)", host_and_ident(FALSE));
1658 smtp_printf("554 SMTP service not available\r\n");
1662 /* Length of options = 0 => there are no options */
1664 else DEBUG(D_receive) debug_printf("no IP options found\n");
1666 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
1668 /* Set keep-alive in socket options. The option is on by default. This
1669 setting is an attempt to get rid of some hanging connections that stick in
1670 read() when the remote end (usually a dialup) goes away. */
1672 if (smtp_accept_keepalive && !sender_host_notsocket)
1673 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
1675 /* If the current host matches host_lookup, set the name by doing a
1676 reverse lookup. On failure, sender_host_name will be NULL and
1677 host_lookup_failed will be TRUE. This may or may not be serious - optional
1680 if (verify_check_host(&host_lookup) == OK)
1682 (void)host_name_lookup();
1683 host_build_sender_fullhost();
1686 /* Delay this until we have the full name, if it is looked up. */
1688 set_process_info("handling incoming connection from %s",
1689 host_and_ident(FALSE));
1691 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
1692 smtps port for use with older style SSL MTAs. */
1695 if (tls_on_connect &&
1696 tls_server_start(tls_require_ciphers) != OK)
1700 /* Test for explicit connection rejection */
1702 if (verify_check_host(&host_reject_connection) == OK)
1704 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
1705 "from %s (host_reject_connection)", host_and_ident(FALSE));
1706 smtp_printf("554 SMTP service not available\r\n");
1710 /* Test with TCP Wrappers if so configured. There is a problem in that
1711 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
1712 such as disks dying. In these cases, it is desirable to reject with a 4xx
1713 error instead of a 5xx error. There isn't a "right" way to detect such
1714 problems. The following kludge is used: errno is zeroed before calling
1715 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
1716 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
1719 #ifdef USE_TCP_WRAPPERS
1721 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
1722 if (tcp_wrappers_name == NULL)
1724 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
1725 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
1726 expand_string_message);
1728 if (!hosts_ctl(tcp_wrappers_name,
1729 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
1730 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
1731 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
1733 if (errno == 0 || errno == ENOENT)
1735 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
1736 log_write(L_connection_reject,
1737 LOG_MAIN|LOG_REJECT, "refused connection from %s "
1738 "(tcp wrappers)", host_and_ident(FALSE));
1739 smtp_printf("554 SMTP service not available\r\n");
1743 int save_errno = errno;
1744 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
1745 "errno value %d\n", save_errno);
1746 log_write(L_connection_reject,
1747 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
1748 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
1749 smtp_printf("451 Temporary local problem - please try later\r\n");
1755 /* Check for reserved slots. The value of smtp_accept_count has already been
1756 incremented to include this process. */
1758 if (smtp_accept_max > 0 &&
1759 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
1761 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
1763 log_write(L_connection_reject,
1764 LOG_MAIN, "temporarily refused connection from %s: not in "
1765 "reserve list: connected=%d max=%d reserve=%d%s",
1766 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
1767 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
1768 smtp_printf("421 %s: Too many concurrent SMTP connections; "
1769 "please try again later\r\n", smtp_active_hostname);
1772 reserved_host = TRUE;
1775 /* If a load level above which only messages from reserved hosts are
1776 accepted is set, check the load. For incoming calls via the daemon, the
1777 check is done in the superior process if there are no reserved hosts, to
1778 save a fork. In all cases, the load average will already be available
1779 in a global variable at this point. */
1781 if (smtp_load_reserve >= 0 &&
1782 load_average > smtp_load_reserve &&
1784 verify_check_host(&smtp_reserve_hosts) != OK)
1786 log_write(L_connection_reject,
1787 LOG_MAIN, "temporarily refused connection from %s: not in "
1788 "reserve list and load average = %.2f", host_and_ident(FALSE),
1789 (double)load_average/1000.0);
1790 smtp_printf("421 %s: Too much load; please try again later\r\n",
1791 smtp_active_hostname);
1795 /* Determine whether unqualified senders or recipients are permitted
1796 for this host. Unfortunately, we have to do this every time, in order to
1797 set the flags so that they can be inspected when considering qualifying
1798 addresses in the headers. For a site that permits no qualification, this
1799 won't take long, however. */
1801 allow_unqualified_sender =
1802 verify_check_host(&sender_unqualified_hosts) == OK;
1804 allow_unqualified_recipient =
1805 verify_check_host(&recipient_unqualified_hosts) == OK;
1807 /* Determine whether HELO/EHLO is required for this host. The requirement
1808 can be hard or soft. */
1810 helo_required = verify_check_host(&helo_verify_hosts) == OK;
1812 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
1814 /* Determine whether this hosts is permitted to send syntactic junk
1815 after a HELO or EHLO command. */
1817 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
1820 /* For batch SMTP input we are now done. */
1822 if (smtp_batched_input) return TRUE;
1824 /* Run the ACL if it exists */
1827 if (acl_smtp_connect != NULL)
1830 rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
1834 (void)smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
1839 /* Output the initial message for a two-way SMTP connection. It may contain
1840 newlines, which then cause a multi-line response to be given. */
1842 code = US"220"; /* Default status code */
1843 esc = US""; /* Default extended status code */
1844 esclen = 0; /* Length of esc */
1846 if (user_msg == NULL)
1848 s = expand_string(smtp_banner);
1850 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
1851 "failed: %s", smtp_banner, expand_string_message);
1857 smtp_message_code(&code, &codelen, &s, NULL);
1861 esclen = codelen - 4;
1865 /* Remove any terminating newlines; might as well remove trailing space too */
1868 while (p > s && isspace(p[-1])) p--;
1871 /* It seems that CC:Mail is braindead, and assumes that the greeting message
1872 is all contained in a single IP packet. The original code wrote out the
1873 greeting using several calls to fprint/fputc, and on busy servers this could
1874 cause it to be split over more than one packet - which caused CC:Mail to fall
1875 over when it got the second part of the greeting after sending its first
1876 command. Sigh. To try to avoid this, build the complete greeting message
1877 first, and output it in one fell swoop. This gives a better chance of it
1878 ending up as a single packet. */
1880 ss = store_get(size);
1884 do /* At least once, in case we have an empty string */
1887 uschar *linebreak = Ustrchr(p, '\n');
1888 ss = string_cat(ss, &size, &ptr, code, 3);
1889 if (linebreak == NULL)
1892 ss = string_cat(ss, &size, &ptr, US" ", 1);
1896 len = linebreak - p;
1897 ss = string_cat(ss, &size, &ptr, US"-", 1);
1899 ss = string_cat(ss, &size, &ptr, esc, esclen);
1900 ss = string_cat(ss, &size, &ptr, p, len);
1901 ss = string_cat(ss, &size, &ptr, US"\r\n", 2);
1903 if (linebreak != NULL) p++;
1907 ss[ptr] = 0; /* string_cat leaves room for this */
1909 /* Before we write the banner, check that there is no input pending, unless
1910 this synchronisation check is disabled. */
1914 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
1915 "synchronization error (input sent without waiting for greeting): "
1916 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
1917 string_printing(smtp_inptr));
1918 smtp_printf("554 SMTP synchronization error\r\n");
1922 /* Now output the banner */
1924 smtp_printf("%s", ss);
1932 /*************************************************
1933 * Handle SMTP syntax and protocol errors *
1934 *************************************************/
1936 /* Write to the log for SMTP syntax errors in incoming commands, if configured
1937 to do so. Then transmit the error response. The return value depends on the
1938 number of syntax and protocol errors in this SMTP session.
1941 type error type, given as a log flag bit
1942 code response code; <= 0 means don't send a response
1943 data data to reflect in the response (can be NULL)
1944 errmess the error message
1946 Returns: -1 limit of syntax/protocol errors NOT exceeded
1947 +1 limit of syntax/protocol errors IS exceeded
1949 These values fit in with the values of the "done" variable in the main
1950 processing loop in smtp_setup_msg(). */
1953 synprot_error(int type, int code, uschar *data, uschar *errmess)
1957 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
1958 (type == L_smtp_syntax_error)? "syntax" : "protocol",
1959 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
1961 if (++synprot_error_count > smtp_max_synprot_errors)
1964 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
1965 "syntax or protocol errors (last command was \"%s\")",
1966 host_and_ident(FALSE), smtp_cmd_buffer);
1971 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
1972 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
1974 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
1983 /*************************************************
1984 * Log incomplete transactions *
1985 *************************************************/
1987 /* This function is called after a transaction has been aborted by RSET, QUIT,
1988 connection drops or other errors. It logs the envelope information received
1989 so far in order to preserve address verification attempts.
1991 Argument: string to indicate what aborted the transaction
1996 incomplete_transaction_log(uschar *what)
1998 if (sender_address == NULL || /* No transaction in progress */
1999 (log_write_selector & L_smtp_incomplete_transaction) == 0 /* Not logging */
2002 /* Build list of recipients for logging */
2004 if (recipients_count > 0)
2007 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2008 for (i = 0; i < recipients_count; i++)
2009 raw_recipients[i] = recipients_list[i].address;
2010 raw_recipients_count = recipients_count;
2013 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2014 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2020 /*************************************************
2021 * Send SMTP response, possibly multiline *
2022 *************************************************/
2024 /* There are, it seems, broken clients out there that cannot handle multiline
2025 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2026 output nothing for non-final calls, and only the first line for anything else.
2029 code SMTP code, may involve extended status codes
2030 codelen length of smtp code; if > 4 there's an ESC
2031 final FALSE if the last line isn't the final line
2032 msg message text, possibly containing newlines
2038 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2043 if (!final && no_multiline_responses) return;
2048 esclen = codelen - 4;
2051 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2052 have had the same. Note: this code is also present in smtp_printf(). It would
2053 be tidier to have it only in one place, but when it was added, it was easier to
2054 do it that way, so as not to have to mess with the code for the RCPT command,
2055 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2057 if (rcpt_in_progress)
2059 if (rcpt_smtp_response == NULL)
2060 rcpt_smtp_response = string_copy(msg);
2061 else if (rcpt_smtp_response_same &&
2062 Ustrcmp(rcpt_smtp_response, msg) != 0)
2063 rcpt_smtp_response_same = FALSE;
2064 rcpt_in_progress = FALSE;
2067 /* Not output the message, splitting it up into multiple lines if necessary. */
2071 uschar *nl = Ustrchr(msg, '\n');
2074 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2077 else if (nl[1] == 0 || no_multiline_responses)
2079 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2080 (int)(nl - msg), msg);
2085 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2087 while (isspace(*msg)) msg++;
2095 /*************************************************
2096 * Parse user SMTP message *
2097 *************************************************/
2099 /* This function allows for user messages overriding the response code details
2100 by providing a suitable response code string at the start of the message
2101 user_msg. Check the message for starting with a response code and optionally an
2102 extended status code. If found, check that the first digit is valid, and if so,
2103 change the code pointer and length to use the replacement. An invalid code
2104 causes a panic log; in this case, if the log messages is the same as the user
2105 message, we must also adjust the value of the log message to show the code that
2106 is actually going to be used (the original one).
2108 This function is global because it is called from receive.c as well as within
2111 Note that the code length returned includes the terminating whitespace
2112 character, which is always included in the regex match.
2115 code SMTP code, may involve extended status codes
2116 codelen length of smtp code; if > 4 there's an ESC
2118 log_msg optional log message, to be adjusted with the new SMTP code
2124 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg)
2129 if (msg == NULL || *msg == NULL) return;
2131 n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2132 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int));
2135 if ((*msg)[0] != (*code)[0])
2137 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2138 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2139 if (log_msg != NULL && *log_msg == *msg)
2140 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2145 *codelen = ovector[1]; /* Includes final space */
2147 *msg += ovector[1]; /* Chop the code off the message */
2154 /*************************************************
2155 * Handle an ACL failure *
2156 *************************************************/
2158 /* This function is called when acl_check() fails. As well as calls from within
2159 this module, it is called from receive.c for an ACL after DATA. It sorts out
2160 logging the incident, and sets up the error response. A message containing
2161 newlines is turned into a multiline SMTP response, but for logging, only the
2164 There's a table of default permanent failure response codes to use in
2165 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2166 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2167 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2168 state, because there are broken clients that try VRFY before RCPT. A 5xx
2169 response should be given only when the address is positively known to be
2170 undeliverable. Sigh. Also, for ETRN, 458 is given on refusal, and for AUTH,
2173 From Exim 4.63, it is possible to override the response code details by
2174 providing a suitable response code string at the start of the message provided
2175 in user_msg. The code's first digit is checked for validity.
2178 where where the ACL was called from
2180 user_msg a message that can be included in an SMTP response
2181 log_msg a message for logging
2183 Returns: 0 in most cases
2184 2 if the failure code was FAIL_DROP, in which case the
2185 SMTP connection should be dropped (this value fits with the
2186 "done" variable in smtp_setup_msg() below)
2190 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2192 BOOL drop = rc == FAIL_DROP;
2196 uschar *sender_info = US"";
2198 #ifdef WITH_CONTENT_SCAN
2199 (where == ACL_WHERE_MIME)? US"during MIME ACL checks" :
2201 (where == ACL_WHERE_PREDATA)? US"DATA" :
2202 (where == ACL_WHERE_DATA)? US"after DATA" :
2203 (smtp_cmd_data == NULL)?
2204 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
2205 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
2207 if (drop) rc = FAIL;
2209 /* Set the default SMTP code, and allow a user message to change it. */
2211 smtp_code = (rc != FAIL)? US"451" : acl_wherecodes[where];
2212 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg);
2214 /* We used to have sender_address here; however, there was a bug that was not
2215 updating sender_address after a rewrite during a verify. When this bug was
2216 fixed, sender_address at this point became the rewritten address. I'm not sure
2217 this is what should be logged, so I've changed to logging the unrewritten
2218 address to retain backward compatibility. */
2220 #ifndef WITH_CONTENT_SCAN
2221 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2223 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2226 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2227 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2228 sender_host_authenticated ? US" A=" : US"",
2229 sender_host_authenticated ? sender_host_authenticated : US"",
2230 sender_host_authenticated && authenticated_id ? US":" : US"",
2231 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2235 /* If there's been a sender verification failure with a specific message, and
2236 we have not sent a response about it yet, do so now, as a preliminary line for
2237 failures, but not defers. However, always log it for defer, and log it for fail
2238 unless the sender_verify_fail log selector has been turned off. */
2240 if (sender_verified_failed != NULL &&
2241 !testflag(sender_verified_failed, af_sverify_told))
2243 BOOL save_rcpt_in_progress = rcpt_in_progress;
2244 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2246 setflag(sender_verified_failed, af_sverify_told);
2248 if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
2249 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2250 host_and_ident(TRUE),
2251 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2252 sender_verified_failed->address,
2253 (sender_verified_failed->message == NULL)? US"" :
2254 string_sprintf(": %s", sender_verified_failed->message));
2256 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2257 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2258 testflag(sender_verified_failed, af_verify_pmfail)?
2259 "Postmaster verification failed while checking <%s>\n%s\n"
2260 "Several RFCs state that you are required to have a postmaster\n"
2261 "mailbox for each mail domain. This host does not accept mail\n"
2262 "from domains whose servers reject the postmaster address."
2264 testflag(sender_verified_failed, af_verify_nsfail)?
2265 "Callback setup failed while verifying <%s>\n%s\n"
2266 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2267 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2268 "RFC requirements, and stops you from receiving standard bounce\n"
2269 "messages. This host does not accept mail from domains whose servers\n"
2272 "Verification failed for <%s>\n%s",
2273 sender_verified_failed->address,
2274 sender_verified_failed->user_message));
2276 rcpt_in_progress = save_rcpt_in_progress;
2279 /* Sort out text for logging */
2281 log_msg = (log_msg == NULL)? US"" : string_sprintf(": %s", log_msg);
2282 lognl = Ustrchr(log_msg, '\n');
2283 if (lognl != NULL) *lognl = 0;
2285 /* Send permanent failure response to the command, but the code used isn't
2286 always a 5xx one - see comments at the start of this function. If the original
2287 rc was FAIL_DROP we drop the connection and yield 2. */
2289 if (rc == FAIL) smtp_respond(smtp_code, codelen, TRUE, (user_msg == NULL)?
2290 US"Administrative prohibition" : user_msg);
2292 /* Send temporary failure response to the command. Don't give any details,
2293 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2294 verb, and for a header verify when smtp_return_error_details is set.
2296 This conditional logic is all somewhat of a mess because of the odd
2297 interactions between temp_details and return_error_details. One day it should
2298 be re-implemented in a tidier fashion. */
2302 if (acl_temp_details && user_msg != NULL)
2304 if (smtp_return_error_details &&
2305 sender_verified_failed != NULL &&
2306 sender_verified_failed->message != NULL)
2308 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2310 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2313 smtp_respond(smtp_code, codelen, TRUE,
2314 US"Temporary local problem - please try later");
2317 /* Log the incident to the logs that are specified by log_reject_target
2318 (default main, reject). This can be empty to suppress logging of rejections. If
2319 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2320 is closing if required and return 2. */
2322 if (log_reject_target != 0)
2323 log_write(0, log_reject_target, "%s %s%srejected %s%s",
2324 host_and_ident(TRUE),
2325 sender_info, (rc == FAIL)? US"" : US"temporarily ", what, log_msg);
2327 if (!drop) return 0;
2329 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
2330 smtp_get_connection_info());
2332 /* Run the not-quit ACL, but without any custom messages. This should not be a
2333 problem, because we get here only if some other ACL has issued "drop", and
2334 in that case, *its* custom messages will have been used above. */
2336 smtp_notquit_exit(US"acl-drop", NULL, NULL);
2343 /*************************************************
2344 * Handle SMTP exit when QUIT is not given *
2345 *************************************************/
2347 /* This function provides a logging/statistics hook for when an SMTP connection
2348 is dropped on the floor or the other end goes away. It's a global function
2349 because it's called from receive.c as well as this module. As well as running
2350 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
2351 response, either with a custom message from the ACL, or using a default. There
2352 is one case, however, when no message is output - after "drop". In that case,
2353 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
2354 passed to this function.
2356 In case things go wrong while processing this function, causing an error that
2357 may re-enter this funtion, there is a recursion check.
2360 reason What $smtp_notquit_reason will be set to in the ACL;
2361 if NULL, the ACL is not run
2362 code The error code to return as part of the response
2363 defaultrespond The default message if there's no user_msg
2369 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
2372 uschar *user_msg = NULL;
2373 uschar *log_msg = NULL;
2375 /* Check for recursive acll */
2377 if (smtp_exit_function_called)
2379 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
2383 smtp_exit_function_called = TRUE;
2385 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
2387 if (acl_smtp_notquit != NULL && reason != NULL)
2389 smtp_notquit_reason = reason;
2390 rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
2393 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
2397 /* Write an SMTP response if we are expected to give one. As the default
2398 responses are all internal, they should always fit in the buffer, but code a
2399 warning, just in case. Note that string_vformat() still leaves a complete
2400 string, even if it is incomplete. */
2402 if (code != NULL && defaultrespond != NULL)
2404 if (user_msg == NULL)
2408 va_start(ap, defaultrespond);
2409 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
2410 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
2411 smtp_printf("%s %s\r\n", code, buffer);
2415 smtp_respond(code, 3, TRUE, user_msg);
2423 /*************************************************
2424 * Verify HELO argument *
2425 *************************************************/
2427 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
2428 matched. It is also called from ACL processing if verify = helo is used and
2429 verification was not previously tried (i.e. helo_try_verify_hosts was not
2430 matched). The result of its processing is to set helo_verified and
2431 helo_verify_failed. These variables should both be FALSE for this function to
2434 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
2435 for IPv6 ::ffff: literals.
2438 Returns: TRUE if testing was completed;
2439 FALSE on a temporary failure
2443 smtp_verify_helo(void)
2447 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
2450 if (sender_helo_name == NULL)
2452 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
2455 /* Deal with the case of -bs without an IP address */
2457 else if (sender_host_address == NULL)
2459 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
2460 helo_verified = TRUE;
2463 /* Deal with the more common case when there is a sending IP address */
2465 else if (sender_helo_name[0] == '[')
2467 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
2468 Ustrlen(sender_host_address)) == 0;
2473 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
2474 helo_verified = Ustrncmp(sender_helo_name + 1,
2475 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
2480 { if (helo_verified) debug_printf("matched host address\n"); }
2483 /* Do a reverse lookup if one hasn't already given a positive or negative
2484 response. If that fails, or the name doesn't match, try checking with a forward
2489 if (sender_host_name == NULL && !host_lookup_failed)
2490 yield = host_name_lookup() != DEFER;
2492 /* If a host name is known, check it and all its aliases. */
2494 if (sender_host_name != NULL)
2496 helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0;
2500 HDEBUG(D_receive) debug_printf("matched host name\n");
2504 uschar **aliases = sender_host_aliases;
2505 while (*aliases != NULL)
2507 helo_verified = strcmpic(*aliases++, sender_helo_name) == 0;
2508 if (helo_verified) break;
2513 debug_printf("matched alias %s\n", *(--aliases));
2518 /* Final attempt: try a forward lookup of the helo name */
2524 h.name = sender_helo_name;
2528 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
2530 rc = host_find_byname(&h, NULL, 0, NULL, TRUE);
2531 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2536 if (Ustrcmp(hh->address, sender_host_address) == 0)
2538 helo_verified = TRUE;
2540 debug_printf("IP address for %s matches calling address\n",
2550 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
2557 /*************************************************
2558 * Send user response message *
2559 *************************************************/
2561 /* This function is passed a default response code and a user message. It calls
2562 smtp_message_code() to check and possibly modify the response code, and then
2563 calls smtp_respond() to transmit the response. I put this into a function
2564 just to avoid a lot of repetition.
2567 code the response code
2568 user_msg the user message
2574 smtp_user_msg(uschar *code, uschar *user_msg)
2577 smtp_message_code(&code, &len, &user_msg, NULL);
2578 smtp_respond(code, len, TRUE, user_msg);
2584 /*************************************************
2585 * Initialize for SMTP incoming message *
2586 *************************************************/
2588 /* This function conducts the initial dialogue at the start of an incoming SMTP
2589 message, and builds a list of recipients. However, if the incoming message
2590 is part of a batch (-bS option) a separate function is called since it would
2591 be messy having tests splattered about all over this function. This function
2592 therefore handles the case where interaction is occurring. The input and output
2593 files are set up in smtp_in and smtp_out.
2595 The global recipients_list is set to point to a vector of recipient_item
2596 blocks, whose number is given by recipients_count. This is extended by the
2597 receive_add_recipient() function. The global variable sender_address is set to
2598 the sender's address. The yield is +1 if a message has been successfully
2599 started, 0 if a QUIT command was encountered or the connection was refused from
2600 the particular host, or -1 if the connection was lost.
2604 Returns: > 0 message successfully started (reached DATA)
2605 = 0 QUIT read or end of file reached or call refused
2610 smtp_setup_msg(void)
2613 BOOL toomany = FALSE;
2614 BOOL discarded = FALSE;
2615 BOOL last_was_rej_mail = FALSE;
2616 BOOL last_was_rcpt = FALSE;
2617 void *reset_point = store_get(0);
2619 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
2621 /* Reset for start of new message. We allow one RSET not to be counted as a
2622 nonmail command, for those MTAs that insist on sending it between every
2623 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
2624 TLS between messages (an Exim client may do this if it has messages queued up
2625 for the host). Note: we do NOT reset AUTH at this point. */
2627 smtp_reset(reset_point);
2628 message_ended = END_NOTSTARTED;
2630 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
2631 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
2632 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
2634 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
2637 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
2639 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
2641 /* Batched SMTP is handled in a different function. */
2643 if (smtp_batched_input) return smtp_setup_batch_msg();
2645 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2646 value. The values are 2 larger than the required yield of the function. */
2651 uschar *etrn_command;
2652 uschar *etrn_serialize_key;
2654 uschar *log_msg, *smtp_code;
2655 uschar *user_msg = NULL;
2656 uschar *recipient = NULL;
2657 uschar *hello = NULL;
2658 uschar *set_id = NULL;
2660 BOOL was_rej_mail = FALSE;
2661 BOOL was_rcpt = FALSE;
2662 void (*oldsignal)(int);
2664 int start, end, sender_domain, recipient_domain;
2669 switch(smtp_read_command(TRUE))
2671 /* The AUTH command is not permitted to occur inside a transaction, and may
2672 occur successfully only once per connection. Actually, that isn't quite
2673 true. When TLS is started, all previous information about a connection must
2674 be discarded, so a new AUTH is permitted at that time.
2676 AUTH may only be used when it has been advertised. However, it seems that
2677 there are clients that send AUTH when it hasn't been advertised, some of
2678 them even doing this after HELO. And there are MTAs that accept this. Sigh.
2679 So there's a get-out that allows this to happen.
2681 AUTH is initially labelled as a "nonmail command" so that one occurrence
2682 doesn't get counted. We change the label here so that multiple failing
2683 AUTHS will eventually hit the nonmail threshold. */
2687 authentication_failed = TRUE;
2688 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
2690 if (!auth_advertised && !allow_auth_unadvertised)
2692 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2693 US"AUTH command used when not advertised");
2696 if (sender_host_authenticated != NULL)
2698 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2699 US"already authenticated");
2702 if (sender_address != NULL)
2704 done = synprot_error(L_smtp_protocol_error, 503, NULL,
2705 US"not permitted in mail transaction");
2711 if (acl_smtp_auth != NULL)
2713 rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, &user_msg, &log_msg);
2716 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
2721 /* Find the name of the requested authentication mechanism. */
2724 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
2726 if (!isalnum(c) && c != '-' && c != '_')
2728 done = synprot_error(L_smtp_syntax_error, 501, NULL,
2729 US"invalid character in authentication mechanism name");
2735 /* If not at the end of the line, we must be at white space. Terminate the
2736 name and move the pointer on to any data that may be present. */
2738 if (*smtp_cmd_data != 0)
2740 *smtp_cmd_data++ = 0;
2741 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
2744 /* Search for an authentication mechanism which is configured for use
2745 as a server and which has been advertised (unless, sigh, allow_auth_
2746 unadvertised is set). */
2748 for (au = auths; au != NULL; au = au->next)
2750 if (strcmpic(s, au->public_name) == 0 && au->server &&
2751 (au->advertised || allow_auth_unadvertised)) break;
2756 done = synprot_error(L_smtp_protocol_error, 504, NULL,
2757 string_sprintf("%s authentication mechanism not supported", s));
2761 /* Run the checking code, passing the remainder of the command line as
2762 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
2763 it as the only set numerical variable. The authenticator may set $auth<n>
2764 and also set other numeric variables. The $auth<n> variables are preferred
2765 nowadays; the numerical variables remain for backwards compatibility.
2767 Afterwards, have a go at expanding the set_id string, even if
2768 authentication failed - for bad passwords it can be useful to log the
2769 userid. On success, require set_id to expand and exist, and put it in
2770 authenticated_id. Save this in permanent store, as the working store gets
2771 reset at HELO, RSET, etc. */
2773 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
2775 expand_nlength[0] = 0; /* $0 contains nothing */
2777 c = (au->info->servercode)(au, smtp_cmd_data);
2778 if (au->set_id != NULL) set_id = expand_string(au->set_id);
2779 expand_nmax = -1; /* Reset numeric variables */
2780 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
2782 /* The value of authenticated_id is stored in the spool file and printed in
2783 log lines. It must not contain binary zeros or newline characters. In
2784 normal use, it never will, but when playing around or testing, this error
2785 can (did) happen. To guard against this, ensure that the id contains only
2786 printing characters. */
2788 if (set_id != NULL) set_id = string_printing(set_id);
2790 /* For the non-OK cases, set up additional logging data if set_id
2795 if (set_id != NULL && *set_id != 0)
2796 set_id = string_sprintf(" (set_id=%s)", set_id);
2800 /* Switch on the result */
2805 if (au->set_id == NULL || set_id != NULL) /* Complete success */
2807 if (set_id != NULL) authenticated_id = string_copy_malloc(set_id);
2808 sender_host_authenticated = au->name;
2809 authentication_failed = FALSE;
2811 protocols[pextend + pauthed + ((tls_active >= 0)? pcrpted:0)] +
2812 ((sender_host_address != NULL)? pnlocal : 0);
2813 s = ss = US"235 Authentication succeeded";
2814 authenticated_by = au;
2818 /* Authentication succeeded, but we failed to expand the set_id string.
2819 Treat this as a temporary error. */
2821 auth_defer_msg = expand_string_message;
2825 s = string_sprintf("435 Unable to authenticate at present%s",
2826 auth_defer_user_msg);
2827 ss = string_sprintf("435 Unable to authenticate at present%s: %s",
2828 set_id, auth_defer_msg);
2832 s = ss = US"501 Invalid base64 data";
2836 s = ss = US"501 Authentication cancelled";
2840 s = ss = US"553 Initial data not expected";
2844 s = US"535 Incorrect authentication data";
2845 ss = string_sprintf("535 Incorrect authentication data%s", set_id);
2849 s = US"435 Internal error";
2850 ss = string_sprintf("435 Internal error%s: return %d from authentication "
2851 "check", set_id, c);
2855 smtp_printf("%s\r\n", s);
2857 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
2858 au->name, host_and_ident(FALSE), ss);
2860 break; /* AUTH_CMD */
2862 /* The HELO/EHLO commands are permitted to appear in the middle of a
2863 session as well as at the beginning. They have the effect of a reset in
2864 addition to their other functions. Their absence at the start cannot be
2865 taken to be an error.
2869 If the EHLO command is not acceptable to the SMTP server, 501, 500,
2870 or 502 failure replies MUST be returned as appropriate. The SMTP
2871 server MUST stay in the same state after transmitting these replies
2872 that it was in before the EHLO was received.
2874 Therefore, we do not do the reset until after checking the command for
2875 acceptability. This change was made for Exim release 4.11. Previously
2876 it did the reset first. */
2889 HELO_EHLO: /* Common code for HELO and EHLO */
2890 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
2891 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
2893 /* Reject the HELO if its argument was invalid or non-existent. A
2894 successful check causes the argument to be saved in malloc store. */
2896 if (!check_helo(smtp_cmd_data))
2898 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
2900 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
2901 "invalid argument(s): %s", hello, host_and_ident(FALSE),
2902 (*smtp_cmd_argument == 0)? US"(no argument given)" :
2903 string_printing(smtp_cmd_argument));
2905 if (++synprot_error_count > smtp_max_synprot_errors)
2907 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2908 "syntax or protocol errors (last command was \"%s\")",
2909 host_and_ident(FALSE), smtp_cmd_buffer);
2916 /* If sender_host_unknown is true, we have got here via the -bs interface,
2917 not called from inetd. Otherwise, we are running an IP connection and the
2918 host address will be set. If the helo name is the primary name of this
2919 host and we haven't done a reverse lookup, force one now. If helo_required
2920 is set, ensure that the HELO name matches the actual host. If helo_verify
2921 is set, do the same check, but softly. */
2923 if (!sender_host_unknown)
2925 BOOL old_helo_verified = helo_verified;
2926 uschar *p = smtp_cmd_data;
2928 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
2931 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
2932 because otherwise the log can be confusing. */
2934 if (sender_host_name == NULL &&
2935 (deliver_domain = sender_helo_name, /* set $domain */
2936 match_isinlist(sender_helo_name, &helo_lookup_domains, 0,
2937 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
2938 (void)host_name_lookup();
2940 /* Rebuild the fullhost info to include the HELO name (and the real name
2941 if it was looked up.) */
2943 host_build_sender_fullhost(); /* Rebuild */
2944 set_process_info("handling%s incoming connection from %s",
2945 (tls_active >= 0)? " TLS" : "", host_and_ident(FALSE));
2947 /* Verify if configured. This doesn't give much security, but it does
2948 make some people happy to be able to do it. If helo_required is set,
2949 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
2950 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
2951 now obsolescent, since the verification can now be requested selectively
2954 helo_verified = helo_verify_failed = FALSE;
2955 if (helo_required || helo_verify)
2957 BOOL tempfail = !smtp_verify_helo();
2962 smtp_printf("%d %s argument does not match calling host\r\n",
2963 tempfail? 451 : 550, hello);
2964 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
2965 tempfail? "temporarily " : "",
2966 hello, sender_helo_name, host_and_ident(FALSE));
2967 helo_verified = old_helo_verified;
2968 break; /* End of HELO/EHLO processing */
2970 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
2971 "helo_try_verify_hosts\n", hello);
2976 #ifdef EXPERIMENTAL_SPF
2977 /* set up SPF context */
2978 spf_init(sender_helo_name, sender_host_address);
2981 /* Apply an ACL check if one is defined; afterwards, recheck
2982 synchronization in case the client started sending in a delay. */
2984 if (acl_smtp_helo != NULL)
2986 rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, &user_msg, &log_msg);
2989 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
2990 sender_helo_name = NULL;
2991 host_build_sender_fullhost(); /* Rebuild */
2994 else if (!check_sync()) goto SYNC_FAILURE;
2997 /* Generate an OK reply. The default string includes the ident if present,
2998 and also the IP address if present. Reflecting back the ident is intended
2999 as a deterrent to mail forgers. For maximum efficiency, and also because
3000 some broken systems expect each response to be in a single packet, arrange
3001 that the entire reply is sent in one write(). */
3003 auth_advertised = FALSE;
3004 pipelining_advertised = FALSE;
3006 tls_advertised = FALSE;
3009 smtp_code = US"250 "; /* Default response code plus space*/
3010 if (user_msg == NULL)
3012 s = string_sprintf("%.3s %s Hello %s%s%s",
3014 smtp_active_hostname,
3015 (sender_ident == NULL)? US"" : sender_ident,
3016 (sender_ident == NULL)? US"" : US" at ",
3017 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3022 if (sender_host_address != NULL)
3024 s = string_cat(s, &size, &ptr, US" [", 2);
3025 s = string_cat(s, &size, &ptr, sender_host_address,
3026 Ustrlen(sender_host_address));
3027 s = string_cat(s, &size, &ptr, US"]", 1);
3031 /* A user-supplied EHLO greeting may not contain more than one line. Note
3032 that the code returned by smtp_message_code() includes the terminating
3033 whitespace character. */
3039 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL);
3040 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3041 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3043 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3044 "newlines: message truncated: %s", string_printing(s));
3051 s = string_cat(s, &size, &ptr, US"\r\n", 2);
3053 /* If we received EHLO, we must create a multiline response which includes
3054 the functions supported. */
3060 /* I'm not entirely happy with this, as an MTA is supposed to check
3061 that it has enough room to accept a message of maximum size before
3062 it sends this. However, there seems little point in not sending it.
3063 The actual size check happens later at MAIL FROM time. By postponing it
3064 till then, VRFY and EXPN can be used after EHLO when space is short. */
3066 if (thismessage_size_limit > 0)
3068 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3069 thismessage_size_limit);
3070 s = string_cat(s, &size, &ptr, big_buffer, Ustrlen(big_buffer));
3074 s = string_cat(s, &size, &ptr, smtp_code, 3);
3075 s = string_cat(s, &size, &ptr, US"-SIZE\r\n", 7);
3078 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3079 clean; if it has an 8-bit character in its hand, it just sends it. It
3080 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3081 However, some users want this option simply in order to stop MUAs
3082 mangling messages that contain top-bit-set characters. It is therefore
3083 provided as an option. */
3085 if (accept_8bitmime)
3087 s = string_cat(s, &size, &ptr, smtp_code, 3);
3088 s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3091 /* Advertise ETRN if there's an ACL checking whether a host is
3092 permitted to issue it; a check is made when any host actually tries. */
3094 if (acl_smtp_etrn != NULL)
3096 s = string_cat(s, &size, &ptr, smtp_code, 3);
3097 s = string_cat(s, &size, &ptr, US"-ETRN\r\n", 7);
3100 /* Advertise EXPN if there's an ACL checking whether a host is
3101 permitted to issue it; a check is made when any host actually tries. */
3103 if (acl_smtp_expn != NULL)
3105 s = string_cat(s, &size, &ptr, smtp_code, 3);
3106 s = string_cat(s, &size, &ptr, US"-EXPN\r\n", 7);
3109 /* Exim is quite happy with pipelining, so let the other end know that
3110 it is safe to use it, unless advertising is disabled. */
3112 if (pipelining_enable &&
3113 verify_check_host(&pipelining_advertise_hosts) == OK)
3115 s = string_cat(s, &size, &ptr, smtp_code, 3);
3116 s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3117 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3118 pipelining_advertised = TRUE;
3121 /* If any server authentication mechanisms are configured, advertise
3122 them if the current host is in auth_advertise_hosts. The problem with
3123 advertising always is that some clients then require users to
3124 authenticate (and aren't configurable otherwise) even though it may not
3125 be necessary (e.g. if the host is in host_accept_relay).
3127 RFC 2222 states that SASL mechanism names contain only upper case
3128 letters, so output the names in upper case, though we actually recognize
3129 them in either case in the AUTH command. */
3133 if (verify_check_host(&auth_advertise_hosts) == OK)
3137 for (au = auths; au != NULL; au = au->next)
3139 if (au->server && (au->advertise_condition == NULL ||
3140 expand_check_condition(au->advertise_condition, au->name,
3141 US"authenticator")))
3146 s = string_cat(s, &size, &ptr, smtp_code, 3);
3147 s = string_cat(s, &size, &ptr, US"-AUTH", 5);
3149 auth_advertised = TRUE;
3152 s = string_cat(s, &size, &ptr, US" ", 1);
3153 s = string_cat(s, &size, &ptr, au->public_name,
3154 Ustrlen(au->public_name));
3155 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3156 au->advertised = TRUE;
3158 else au->advertised = FALSE;
3160 if (!first) s = string_cat(s, &size, &ptr, US"\r\n", 2);
3164 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3165 if it has been included in the binary, and the host matches
3166 tls_advertise_hosts. We must *not* advertise if we are already in a
3167 secure connection. */
3170 if (tls_active < 0 &&
3171 verify_check_host(&tls_advertise_hosts) != FAIL)
3173 s = string_cat(s, &size, &ptr, smtp_code, 3);
3174 s = string_cat(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3175 tls_advertised = TRUE;
3179 /* Finish off the multiline reply with one that is always available. */
3181 s = string_cat(s, &size, &ptr, smtp_code, 3);
3182 s = string_cat(s, &size, &ptr, US" HELP\r\n", 7);
3185 /* Terminate the string (for debug), write it, and note that HELO/EHLO
3191 if (tls_active >= 0) (void)tls_write(s, ptr); else
3194 (void)fwrite(s, 1, ptr, smtp_out);
3198 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
3199 memmove(cr, cr + 1, (ptr--) - (cr - s));
3200 debug_printf("SMTP>> %s", s);
3204 /* Reset the protocol and the state, abandoning any previous message. */
3206 received_protocol = (esmtp?
3208 ((sender_host_authenticated != NULL)? pauthed : 0) +
3209 ((tls_active >= 0)? pcrpted : 0)]
3211 protocols[pnormal + ((tls_active >= 0)? pcrpted : 0)])
3213 ((sender_host_address != NULL)? pnlocal : 0);
3215 smtp_reset(reset_point);
3217 break; /* HELO/EHLO */
3220 /* The MAIL command requires an address as an operand. All we do
3221 here is to parse it for syntactic correctness. The form "<>" is
3222 a special case which converts into an empty string. The start/end
3223 pointers in the original are not used further for this address, as
3224 it is the canonical extracted address which is all that is kept. */
3228 smtp_mailcmd_count++; /* Count for limit and ratelimit */
3229 was_rej_mail = TRUE; /* Reset if accepted */
3230 env_mail_type_t * mail_args; /* Sanity check & validate args */
3232 if (helo_required && !helo_seen)
3234 smtp_printf("503 HELO or EHLO required\r\n");
3235 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
3236 "HELO/EHLO given", host_and_ident(FALSE));
3240 if (sender_address != NULL)
3242 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3243 US"sender already given");
3247 if (smtp_cmd_data[0] == 0)
3249 done = synprot_error(L_smtp_protocol_error, 501, NULL,
3250 US"MAIL must have an address operand");
3254 /* Check to see if the limit for messages per connection would be
3255 exceeded by accepting further messages. */
3257 if (smtp_accept_max_per_connection > 0 &&
3258 smtp_mailcmd_count > smtp_accept_max_per_connection)
3260 smtp_printf("421 too many messages in this connection\r\n");
3261 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
3262 "messages in one connection", host_and_ident(TRUE));
3266 /* Reset for start of message - even if this is going to fail, we
3267 obviously need to throw away any previous data. */
3269 smtp_reset(reset_point);
3271 sender_data = recipient_data = NULL;
3273 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
3277 uschar *name, *value, *end;
3278 unsigned long int size;
3279 BOOL arg_error = FALSE;
3281 if (!extract_option(&name, &value)) break;
3283 for (mail_args = env_mail_type_list;
3284 (char *)mail_args < (char *)env_mail_type_list + sizeof(env_mail_type_list);
3288 if (strcmpic(name, mail_args->name) == 0)
3291 if (mail_args->need_value && strcmpic(value, US"") == 0)
3293 /* This doesn't seem right to use
3294 if ((char *)mail_args >= (char *)env_mail_type_list + sizeof(env_mail_type_list))
3298 switch(mail_args->value)
3300 /* Handle SIZE= by reading the value. We don't do the check till later,
3301 in order to be able to log the sender address on failure. */
3302 case ENV_MAIL_OPT_SIZE:
3303 /* if (strcmpic(name, US"SIZE") == 0 && */
3304 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
3306 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
3308 message_size = (int)size;
3314 /* If this session was initiated with EHLO and accept_8bitmime is set,
3315 Exim will have indicated that it supports the BODY=8BITMIME option. In
3316 fact, it does not support this according to the RFCs, in that it does not
3317 take any special action for forwarding messages containing 8-bit
3318 characters. That is why accept_8bitmime is not the default setting, but
3319 some sites want the action that is provided. We recognize both "8BITMIME"
3320 and "7BIT" as body types, but take no action. */
3321 case ENV_MAIL_OPT_BODY:
3322 if (accept_8bitmime &&
3323 (strcmpic(value, US"8BITMIME") == 0 ||
3324 strcmpic(value, US"7BIT") == 0) )
3329 /* Handle the AUTH extension. If the value given is not "<>" and either
3330 the ACL says "yes" or there is no ACL but the sending host is
3331 authenticated, we set it up as the authenticated sender. However, if the
3332 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
3333 the condition is met. The value of AUTH is an xtext, which means that +,
3334 = and cntrl chars are coded in hex; however "<>" is unaffected by this
3336 case ENV_MAIL_OPT_AUTH:
3337 if (Ustrcmp(value, "<>") != 0)
3342 if (auth_xtextdecode(value, &authenticated_sender) < 0)
3344 /* Put back terminator overrides for error message */
3347 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3348 US"invalid data for AUTH");
3351 if (acl_smtp_mailauth == NULL)
3353 ignore_msg = US"client not authenticated";
3354 rc = (sender_host_authenticated != NULL)? OK : FAIL;
3358 ignore_msg = US"rejected by ACL";
3359 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
3360 &user_msg, &log_msg);
3366 if (authenticated_by == NULL ||
3367 authenticated_by->mail_auth_condition == NULL ||
3368 expand_check_condition(authenticated_by->mail_auth_condition,
3369 authenticated_by->name, US"authenticator"))
3370 break; /* Accept the AUTH */
3372 ignore_msg = US"server_mail_auth_condition failed";
3373 if (authenticated_id != NULL)
3374 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
3375 ignore_msg, authenticated_id);
3380 authenticated_sender = NULL;
3381 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
3382 value, host_and_ident(TRUE), ignore_msg);
3385 /* Should only get DEFER or ERROR here. Put back terminator
3386 overrides for error message */
3391 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
3398 /* Unknown option. Stick back the terminator characters and break
3399 the loop. An error for a malformed address will occur. */
3402 /* BAD_MAIL_ARGS: */
3407 /* Break out of for loop if switch() had bad argument or
3408 when start of the email address is reached */
3409 if (arg_error) break;
3412 /* If we have passed the threshold for rate limiting, apply the current
3413 delay, and update it for next time, provided this is a limited host. */
3415 if (smtp_mailcmd_count > smtp_rlm_threshold &&
3416 verify_check_host(&smtp_ratelimit_hosts) == OK)
3418 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
3419 smtp_delay_mail/1000.0);
3420 millisleep((int)smtp_delay_mail);
3421 smtp_delay_mail *= smtp_rlm_factor;
3422 if (smtp_delay_mail > (double)smtp_rlm_limit)
3423 smtp_delay_mail = (double)smtp_rlm_limit;
3426 /* Now extract the address, first applying any SMTP-time rewriting. The
3427 TRUE flag allows "<>" as a sender address. */
3429 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
3430 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3431 global_rewrite_rules) : smtp_cmd_data;
3433 /* rfc821_domains = TRUE; << no longer needed */
3435 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
3437 /* rfc821_domains = FALSE; << no longer needed */
3439 if (raw_sender == NULL)
3441 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3445 sender_address = raw_sender;
3447 /* If there is a configured size limit for mail, check that this message
3448 doesn't exceed it. The check is postponed to this point so that the sender
3451 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
3453 smtp_printf("552 Message size exceeds maximum permitted\r\n");
3454 log_write(L_size_reject,
3455 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
3456 "message too big: size%s=%d max=%d",
3458 host_and_ident(TRUE),
3459 (message_size == INT_MAX)? ">" : "",
3461 thismessage_size_limit);
3462 sender_address = NULL;
3466 /* Check there is enough space on the disk unless configured not to.
3467 When smtp_check_spool_space is set, the check is for thismessage_size_limit
3468 plus the current message - i.e. we accept the message only if it won't
3469 reduce the space below the threshold. Add 5000 to the size to allow for
3470 overheads such as the Received: line and storing of recipients, etc.
3471 By putting the check here, even when SIZE is not given, it allow VRFY
3472 and EXPN etc. to be used when space is short. */
3474 if (!receive_check_fs(
3475 (smtp_check_spool_space && message_size >= 0)?
3476 message_size + 5000 : 0))
3478 smtp_printf("452 Space shortage, please try later\r\n");
3479 sender_address = NULL;
3483 /* If sender_address is unqualified, reject it, unless this is a locally
3484 generated message, or the sending host or net is permitted to send
3485 unqualified addresses - typically local machines behaving as MUAs -
3486 in which case just qualify the address. The flag is set above at the start
3487 of the SMTP connection. */
3489 if (sender_domain == 0 && sender_address[0] != 0)
3491 if (allow_unqualified_sender)
3493 sender_domain = Ustrlen(sender_address) + 1;
3494 sender_address = rewrite_address_qualify(sender_address, FALSE);
3495 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3500 smtp_printf("501 %s: sender address must contain a domain\r\n",
3502 log_write(L_smtp_syntax_error,
3503 LOG_MAIN|LOG_REJECT,
3504 "unqualified sender rejected: <%s> %s%s",
3506 host_and_ident(TRUE),
3508 sender_address = NULL;
3513 /* Apply an ACL check if one is defined, before responding. Afterwards,
3514 when pipelining is not advertised, do another sync check in case the ACL
3515 delayed and the client started sending in the meantime. */
3517 if (acl_smtp_mail == NULL) rc = OK; else
3519 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
3520 if (rc == OK && !pipelining_advertised && !check_sync())
3524 if (rc == OK || rc == DISCARD)
3526 if (user_msg == NULL) smtp_printf("250 OK\r\n");
3527 else smtp_user_msg(US"250", user_msg);
3528 smtp_delay_rcpt = smtp_rlr_base;
3529 recipients_discarded = (rc == DISCARD);
3530 was_rej_mail = FALSE;
3534 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
3535 sender_address = NULL;
3540 /* The RCPT command requires an address as an operand. There may be any
3541 number of RCPT commands, specifying multiple recipients. We build them all
3542 into a data structure. The start/end values given by parse_extract_address
3543 are not used, as we keep only the extracted address. */
3548 was_rcpt = rcpt_in_progress = TRUE;
3550 /* There must be a sender address; if the sender was rejected and
3551 pipelining was advertised, we assume the client was pipelining, and do not
3552 count this as a protocol error. Reset was_rej_mail so that further RCPTs
3553 get the same treatment. */
3555 if (sender_address == NULL)
3557 if (pipelining_advertised && last_was_rej_mail)
3559 smtp_printf("503 sender not yet given\r\n");
3560 was_rej_mail = TRUE;
3564 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3565 US"sender not yet given");
3566 was_rcpt = FALSE; /* Not a valid RCPT */
3572 /* Check for an operand */
3574 if (smtp_cmd_data[0] == 0)
3576 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3577 US"RCPT must have an address operand");
3582 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
3583 as a recipient address */
3585 recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
3586 rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
3587 global_rewrite_rules) : smtp_cmd_data;
3589 /* rfc821_domains = TRUE; << no longer needed */
3590 recipient = parse_extract_address(recipient, &errmess, &start, &end,
3591 &recipient_domain, FALSE);
3592 /* rfc821_domains = FALSE; << no longer needed */
3594 if (recipient == NULL)
3596 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
3601 /* If the recipient address is unqualified, reject it, unless this is a
3602 locally generated message. However, unqualified addresses are permitted
3603 from a configured list of hosts and nets - typically when behaving as
3604 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
3605 really. The flag is set at the start of the SMTP connection.
3607 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
3608 assumed this meant "reserved local part", but the revision of RFC 821 and
3609 friends now makes it absolutely clear that it means *mailbox*. Consequently
3610 we must always qualify this address, regardless. */
3612 if (recipient_domain == 0)
3614 if (allow_unqualified_recipient ||
3615 strcmpic(recipient, US"postmaster") == 0)
3617 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3619 recipient_domain = Ustrlen(recipient) + 1;
3620 recipient = rewrite_address_qualify(recipient, TRUE);
3625 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3627 log_write(L_smtp_syntax_error,
3628 LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
3629 "<%s> %s%s", recipient, host_and_ident(TRUE),
3635 /* Check maximum allowed */
3637 if (rcpt_count > recipients_max && recipients_max > 0)
3639 if (recipients_max_reject)
3642 smtp_printf("552 too many recipients\r\n");
3644 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
3645 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
3650 smtp_printf("452 too many recipients\r\n");
3652 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
3653 "temporarily rejected: sender=<%s> %s", sender_address,
3654 host_and_ident(TRUE));
3661 /* If we have passed the threshold for rate limiting, apply the current
3662 delay, and update it for next time, provided this is a limited host. */
3664 if (rcpt_count > smtp_rlr_threshold &&
3665 verify_check_host(&smtp_ratelimit_hosts) == OK)
3667 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
3668 smtp_delay_rcpt/1000.0);
3669 millisleep((int)smtp_delay_rcpt);
3670 smtp_delay_rcpt *= smtp_rlr_factor;
3671 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
3672 smtp_delay_rcpt = (double)smtp_rlr_limit;
3675 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
3676 for them. Otherwise, check the access control list for this recipient. As
3677 there may be a delay in this, re-check for a synchronization error
3678 afterwards, unless pipelining was advertised. */
3680 if (recipients_discarded) rc = DISCARD; else
3682 rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
3684 if (rc == OK && !pipelining_advertised && !check_sync())
3688 /* The ACL was happy */
3692 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3693 else smtp_user_msg(US"250", user_msg);
3694 receive_add_recipient(recipient, -1);
3697 /* The recipient was discarded */
3699 else if (rc == DISCARD)
3701 if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
3702 else smtp_user_msg(US"250", user_msg);
3705 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> rejected RCPT %s: "
3706 "discarded by %s ACL%s%s", host_and_ident(TRUE),
3707 (sender_address_unrewritten != NULL)?
3708 sender_address_unrewritten : sender_address,
3709 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
3710 (log_msg == NULL)? US"" : US": ",
3711 (log_msg == NULL)? US"" : log_msg);
3714 /* Either the ACL failed the address, or it was deferred. */
3718 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
3719 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
3724 /* The DATA command is legal only if it follows successful MAIL FROM
3725 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
3726 not counted as a protocol error if it follows RCPT (which must have been
3727 rejected if there are no recipients.) This function is complete when a
3728 valid DATA command is encountered.
3730 Note concerning the code used: RFC 2821 says this:
3732 - If there was no MAIL, or no RCPT, command, or all such commands
3733 were rejected, the server MAY return a "command out of sequence"
3734 (503) or "no valid recipients" (554) reply in response to the
3737 The example in the pipelining RFC 2920 uses 554, but I use 503 here
3738 because it is the same whether pipelining is in use or not.
3740 If all the RCPT commands that precede DATA provoked the same error message
3741 (often indicating some kind of system error), it is helpful to include it
3742 with the DATA rejection (an idea suggested by Tony Finch). */
3746 if (!discarded && recipients_count <= 0)
3748 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
3750 uschar *code = US"503";
3751 int len = Ustrlen(rcpt_smtp_response);
3752 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
3754 /* Responses from smtp_printf() will have \r\n on the end */
3755 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
3756 rcpt_smtp_response[len-2] = 0;
3757 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
3759 if (pipelining_advertised && last_was_rcpt)
3760 smtp_printf("503 Valid RCPT command must precede DATA\r\n");
3762 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3763 US"valid RCPT command must precede DATA");
3767 if (toomany && recipients_max_reject)
3769 sender_address = NULL; /* This will allow a new MAIL without RSET */
3770 sender_address_unrewritten = NULL;
3771 smtp_printf("554 Too many recipients\r\n");
3775 /* If there is an ACL, re-check the synchronization afterwards, since the
3776 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
3777 to get the DATA command sent. */
3779 if (acl_smtp_predata == NULL && cutthrough_fd < 0) rc = OK; else
3781 uschar * acl= acl_smtp_predata ? acl_smtp_predata : US"accept";
3782 enable_dollar_recipients = TRUE;
3783 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
3785 enable_dollar_recipients = FALSE;
3786 if (rc == OK && !check_sync()) goto SYNC_FAILURE;
3791 if (user_msg == NULL)
3792 smtp_printf("354 Enter message, ending with \".\" on a line by itself\r\n");
3793 else smtp_user_msg(US"354", user_msg);
3795 message_ended = END_NOTENDED; /* Indicate in middle of data */
3798 /* Either the ACL failed the address, or it was deferred. */
3801 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
3807 rc = acl_check(ACL_WHERE_VRFY, NULL, acl_smtp_vrfy, &user_msg, &log_msg);
3809 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
3815 /* rfc821_domains = TRUE; << no longer needed */
3816 address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
3817 &recipient_domain, FALSE);
3818 /* rfc821_domains = FALSE; << no longer needed */
3820 if (address == NULL)
3821 s = string_sprintf("501 %s", errmess);
3824 address_item *addr = deliver_make_addr(address, FALSE);
3825 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
3826 -1, -1, NULL, NULL, NULL))
3829 s = string_sprintf("250 <%s> is deliverable", address);
3833 s = (addr->user_message != NULL)?
3834 string_sprintf("451 <%s> %s", address, addr->user_message) :
3835 string_sprintf("451 Cannot resolve <%s> at this time", address);
3839 s = (addr->user_message != NULL)?
3840 string_sprintf("550 <%s> %s", address, addr->user_message) :
3841 string_sprintf("550 <%s> is not deliverable", address);
3842 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
3843 smtp_cmd_argument, host_and_ident(TRUE));
3848 smtp_printf("%s\r\n", s);
3855 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
3857 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
3860 BOOL save_log_testing_mode = log_testing_mode;
3861 address_test_mode = log_testing_mode = TRUE;
3862 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
3863 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
3865 address_test_mode = FALSE;
3866 log_testing_mode = save_log_testing_mode; /* true for -bh */
3875 if (!tls_advertised)
3877 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3878 US"STARTTLS command used when not advertised");
3882 /* Apply an ACL check if one is defined */
3884 if (acl_smtp_starttls != NULL)
3886 rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, &user_msg,
3890 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
3895 /* RFC 2487 is not clear on when this command may be sent, though it
3896 does state that all information previously obtained from the client
3897 must be discarded if a TLS session is started. It seems reasonble to
3898 do an implied RSET when STARTTLS is received. */
3900 incomplete_transaction_log(US"STARTTLS");
3901 smtp_reset(reset_point);
3903 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
3905 /* There's an attack where more data is read in past the STARTTLS command
3906 before TLS is negotiated, then assumed to be part of the secure session
3907 when used afterwards; we use segregated input buffers, so are not
3908 vulnerable, but we want to note when it happens and, for sheer paranoia,
3909 ensure that the buffer is "wiped".
3910 Pipelining sync checks will normally have protected us too, unless disabled
3911 by configuration. */
3913 if (receive_smtp_buffered())
3916 debug_printf("Non-empty input buffer after STARTTLS; naive attack?");
3918 smtp_inend = smtp_inptr = smtp_inbuffer;
3919 /* and if TLS is already active, tls_server_start() should fail */
3922 /* There is nothing we value in the input buffer and if TLS is succesfully
3923 negotiated, we won't use this buffer again; if TLS fails, we'll just read
3924 fresh content into it. The buffer contains arbitrary content from an
3925 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
3926 It seems safest to just wipe away the content rather than leave it as a
3927 target to jump to. */
3929 memset(smtp_inbuffer, 0, in_buffer_size);
3931 /* Attempt to start up a TLS session, and if successful, discard all
3932 knowledge that was obtained previously. At least, that's what the RFC says,
3933 and that's what happens by default. However, in order to work round YAEB,
3934 there is an option to remember the esmtp state. Sigh.
3936 We must allow for an extra EHLO command and an extra AUTH command after
3937 STARTTLS that don't add to the nonmail command count. */
3939 if ((rc = tls_server_start(tls_require_ciphers)) == OK)
3941 if (!tls_remember_esmtp)
3942 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
3943 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3944 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
3945 if (sender_helo_name != NULL)
3947 store_free(sender_helo_name);
3948 sender_helo_name = NULL;
3949 host_build_sender_fullhost(); /* Rebuild */
3950 set_process_info("handling incoming TLS connection from %s",
3951 host_and_ident(FALSE));
3953 received_protocol = (esmtp?
3954 protocols[pextend + pcrpted +
3955 ((sender_host_authenticated != NULL)? pauthed : 0)]
3957 protocols[pnormal + pcrpted])
3959 ((sender_host_address != NULL)? pnlocal : 0);
3961 sender_host_authenticated = NULL;
3962 authenticated_id = NULL;
3963 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
3964 DEBUG(D_tls) debug_printf("TLS active\n");
3965 break; /* Successful STARTTLS */
3968 /* Some local configuration problem was discovered before actually trying
3969 to do a TLS handshake; give a temporary error. */
3971 else if (rc == DEFER)
3973 smtp_printf("454 TLS currently unavailable\r\n");
3977 /* Hard failure. Reject everything except QUIT or closed connection. One
3978 cause for failure is a nested STARTTLS, in which case tls_active remains
3979 set, but we must still reject all incoming commands. */
3981 DEBUG(D_tls) debug_printf("TLS failed to start\n");
3984 switch(smtp_read_command(FALSE))
3987 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
3988 smtp_get_connection_info());
3989 smtp_notquit_exit(US"tls-failed", NULL, NULL);
3993 /* It is perhaps arguable as to which exit ACL should be called here,
3994 but as it is probably a situtation that almost never arises, it
3995 probably doesn't matter. We choose to call the real QUIT ACL, which in
3996 some sense is perhaps "right". */
4000 if (acl_smtp_quit != NULL)
4002 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
4005 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4008 if (user_msg == NULL)
4009 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4011 smtp_respond(US"221", 3, TRUE, user_msg);
4012 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4013 smtp_get_connection_info());
4018 smtp_printf("554 Security failure\r\n");
4027 /* The ACL for QUIT is provided for gathering statistical information or
4028 similar; it does not affect the response code, but it can supply a custom
4033 incomplete_transaction_log(US"QUIT");
4034 if (acl_smtp_quit != NULL)
4036 rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
4038 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
4041 if (user_msg == NULL)
4042 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
4044 smtp_respond(US"221", 3, TRUE, user_msg);
4051 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
4052 smtp_get_connection_info());
4058 incomplete_transaction_log(US"RSET");
4059 smtp_reset(reset_point);
4061 smtp_printf("250 Reset OK\r\n");
4062 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
4068 smtp_printf("250 OK\r\n");
4072 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
4073 used, a check will be done for permitted hosts. Show STARTTLS only if not
4074 already in a TLS session and if it would be advertised in the EHLO
4079 smtp_printf("214-Commands supported:\r\n");
4083 Ustrcat(buffer, " AUTH");
4085 if (tls_active < 0 &&
4086 verify_check_host(&tls_advertise_hosts) != FAIL)
4087 Ustrcat(buffer, " STARTTLS");
4089 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
4090 Ustrcat(buffer, " NOOP QUIT RSET HELP");
4091 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
4092 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
4093 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
4094 smtp_printf("214%s\r\n", buffer);
4100 incomplete_transaction_log(US"connection lost");
4101 smtp_notquit_exit(US"connection-lost", US"421",
4102 US"%s lost input connection", smtp_active_hostname);
4104 /* Don't log by default unless in the middle of a message, as some mailers
4105 just drop the call rather than sending QUIT, and it clutters up the logs.
4108 if (sender_address != NULL || recipients_count > 0)
4109 log_write(L_lost_incoming_connection,
4111 "unexpected %s while reading SMTP command from %s%s",
4112 sender_host_unknown? "EOF" : "disconnection",
4113 host_and_ident(FALSE), smtp_read_error);
4115 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
4116 smtp_get_connection_info(), smtp_read_error);
4124 if (sender_address != NULL)
4126 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4127 US"ETRN is not permitted inside a transaction");
4131 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
4132 host_and_ident(FALSE));
4134 rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, &user_msg, &log_msg);
4137 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
4141 /* Compute the serialization key for this command. */
4143 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
4145 /* If a command has been specified for running as a result of ETRN, we
4146 permit any argument to ETRN. If not, only the # standard form is permitted,
4147 since that is strictly the only kind of ETRN that can be implemented
4148 according to the RFC. */
4150 if (smtp_etrn_command != NULL)
4154 etrn_command = smtp_etrn_command;
4155 deliver_domain = smtp_cmd_data;
4156 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
4157 US"ETRN processing", &error);
4158 deliver_domain = NULL;
4161 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
4163 smtp_printf("458 Internal failure\r\n");
4168 /* Else set up to call Exim with the -R option. */
4172 if (*smtp_cmd_data++ != '#')
4174 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4175 US"argument must begin with #");
4178 etrn_command = US"exim -R";
4179 argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
4183 /* If we are host-testing, don't actually do anything. */
4189 debug_printf("ETRN command is: %s\n", etrn_command);
4190 debug_printf("ETRN command execution skipped\n");
4192 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4193 else smtp_user_msg(US"250", user_msg);
4198 /* If ETRN queue runs are to be serialized, check the database to
4199 ensure one isn't already running. */
4201 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
4203 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
4207 /* Fork a child process and run the command. We don't want to have to
4208 wait for the process at any point, so set SIGCHLD to SIG_IGN before
4209 forking. It should be set that way anyway for external incoming SMTP,
4210 but we save and restore to be tidy. If serialization is required, we
4211 actually run the command in yet another process, so we can wait for it
4212 to complete and then remove the serialization lock. */
4214 oldsignal = signal(SIGCHLD, SIG_IGN);
4216 if ((pid = fork()) == 0)
4218 smtp_input = FALSE; /* This process is not associated with the */
4219 (void)fclose(smtp_in); /* SMTP call any more. */
4220 (void)fclose(smtp_out);
4222 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
4224 /* If not serializing, do the exec right away. Otherwise, fork down
4225 into another process. */
4227 if (!smtp_etrn_serialize || (pid = fork()) == 0)
4229 DEBUG(D_exec) debug_print_argv(argv);
4230 exim_nullstd(); /* Ensure std{in,out,err} exist */
4231 execv(CS argv[0], (char *const *)argv);
4232 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
4233 etrn_command, strerror(errno));
4234 _exit(EXIT_FAILURE); /* paranoia */
4237 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
4238 is, we are in the first subprocess, after forking again. All we can do
4239 for a failing fork is to log it. Otherwise, wait for the 2nd process to
4240 complete, before removing the serialization. */
4243 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
4244 "failed: %s", strerror(errno));
4248 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
4250 (void)wait(&status);
4251 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
4255 enq_end(etrn_serialize_key);
4256 _exit(EXIT_SUCCESS);
4259 /* Back in the top level SMTP process. Check that we started a subprocess
4260 and restore the signal state. */
4264 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
4266 smtp_printf("458 Unable to fork process\r\n");
4267 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
4271 if (user_msg == NULL) smtp_printf("250 OK\r\n");
4272 else smtp_user_msg(US"250", user_msg);
4275 signal(SIGCHLD, oldsignal);
4280 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4281 US"unexpected argument data");
4285 /* This currently happens only for NULLs, but could be extended. */
4288 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
4289 US"NULL character(s) present (shown as '?')");
4290 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
4296 if (smtp_inend >= smtp_inbuffer + in_buffer_size)
4297 smtp_inend = smtp_inbuffer + in_buffer_size - 1;
4298 c = smtp_inend - smtp_inptr;
4299 if (c > 150) c = 150;
4301 incomplete_transaction_log(US"sync failure");
4302 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
4303 "(next input sent too soon: pipelining was%s advertised): "
4304 "rejected \"%s\" %s next input=\"%s\"",
4305 pipelining_advertised? "" : " not",
4306 smtp_cmd_buffer, host_and_ident(TRUE),
4307 string_printing(smtp_inptr));
4308 smtp_notquit_exit(US"synchronization-error", US"554",
4309 US"SMTP synchronization error");
4310 done = 1; /* Pretend eof - drops connection */
4314 case TOO_MANY_NONMAIL_CMD:
4315 s = smtp_cmd_buffer;
4316 while (*s != 0 && !isspace(*s)) s++;
4317 incomplete_transaction_log(US"too many non-mail commands");
4318 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4319 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
4320 s - smtp_cmd_buffer, smtp_cmd_buffer);
4321 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
4322 done = 1; /* Pretend eof - drops connection */
4327 if (unknown_command_count++ >= smtp_max_unknown_commands)
4329 log_write(L_smtp_syntax_error, LOG_MAIN,
4330 "SMTP syntax error in \"%s\" %s %s",
4331 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
4332 US"unrecognized command");
4333 incomplete_transaction_log(US"unrecognized command");
4334 smtp_notquit_exit(US"bad-commands", US"500",
4335 US"Too many unrecognized commands");
4337 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4338 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
4342 done = synprot_error(L_smtp_syntax_error, 500, NULL,
4343 US"unrecognized command");
4347 /* This label is used by goto's inside loops that want to break out to
4348 the end of the command-processing loop. */
4351 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
4352 last_was_rcpt = was_rcpt; /* protocol error handling */
4356 return done - 2; /* Convert yield values */
4359 /* End of smtp_in.c */
git://git.exim.org / exim.git / blob