1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2017 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for handling an incoming SMTP call. */
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
19 #ifdef USE_TCP_WRAPPERS
22 #define EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
47 #define SMTP_CMD_BUFFER_SIZE 16384
49 /* Size of buffer for reading SMTP incoming packets */
51 #define IN_BUFFER_SIZE 8192
53 /* Structure for SMTP command list */
60 short int is_mail_cmd;
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
77 /* This is a dummy to identify the non-sync commands when pipelining */
79 NON_SYNC_CMD_PIPELINING,
81 /* These commands need not be synchronized when pipelining */
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
85 /* This is a dummy to identify the non-sync commands when not pipelining */
87 NON_SYNC_CMD_NON_PIPELINING,
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
108 /* I'm not sure about these, but I don't think they matter. */
113 PROXY_FAIL_IGNORE_CMD,
116 /* These are specials that don't correspond to actual commands */
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
130 /*************************************************
131 * Local static variables *
132 *************************************************/
134 static auth_instance *authenticated_by;
135 static BOOL auth_advertised;
137 static BOOL tls_advertised;
139 static BOOL dsn_advertised;
141 static BOOL helo_required = FALSE;
142 static BOOL helo_verify = FALSE;
143 static BOOL helo_seen;
144 static BOOL helo_accept_junk;
145 static BOOL count_nonmail;
146 static BOOL pipelining_advertised;
147 static BOOL rcpt_smtp_response_same;
148 static BOOL rcpt_in_progress;
149 static int nonmail_command_count;
150 static BOOL smtp_exit_function_called = 0;
152 static BOOL smtputf8_advertised;
154 static int synprot_error_count;
155 static int unknown_command_count;
156 static int sync_cmd_limit;
157 static int smtp_write_error = 0;
159 static uschar *rcpt_smtp_response;
160 static uschar *smtp_data_buffer;
161 static uschar *smtp_cmd_data;
163 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
164 final fields of all except AUTH are forced TRUE at the start of a new message
165 setup, to allow one of each between messages that is not counted as a nonmail
166 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
167 allow a new EHLO after starting up TLS.
169 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
170 counted. However, the flag is changed when AUTH is received, so that multiple
171 failing AUTHs will eventually hit the limit. After a successful AUTH, another
172 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
173 forced TRUE, to allow for the re-authentication that can happen at that point.
175 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
176 count of non-mail commands and possibly provoke an error.
178 tls_auth is a pseudo-command, never expected in input. It is activated
179 on TLS startup and looks for a tls authenticator. */
181 static smtp_cmd_list cmd_list[] = {
182 /* name len cmd has_arg is_mail_cmd */
184 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
185 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
186 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
187 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
189 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
190 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, TRUE },
193 /* If you change anything above here, also fix the definitions below. */
195 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
196 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
197 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
198 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
199 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
200 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
201 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
202 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
203 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
204 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
207 static smtp_cmd_list *cmd_list_end =
208 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
210 #define CMD_LIST_RSET 0
211 #define CMD_LIST_HELO 1
212 #define CMD_LIST_EHLO 2
213 #define CMD_LIST_AUTH 3
214 #define CMD_LIST_STARTTLS 4
215 #define CMD_LIST_TLS_AUTH 5
217 /* This list of names is used for performing the smtp_no_mail logging action.
218 It must be kept in step with the SCH_xxx enumerations. */
220 static uschar *smtp_names[] =
222 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
223 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
224 US"STARTTLS", US"VRFY" };
226 static uschar *protocols_local[] = {
227 US"local-smtp", /* HELO */
228 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
229 US"local-esmtp", /* EHLO */
230 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
231 US"local-esmtpa", /* EHLO->AUTH */
232 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
234 static uschar *protocols[] = {
236 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
237 US"esmtp", /* EHLO */
238 US"esmtps", /* EHLO->STARTTLS->EHLO */
239 US"esmtpa", /* EHLO->AUTH */
240 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
245 #define pcrpted 1 /* added to pextend or pnormal */
246 #define pauthed 2 /* added to pextend */
248 /* Sanity check and validate optional args to MAIL FROM: envelope */
251 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
255 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
261 uschar * name; /* option requested during MAIL cmd */
262 int value; /* enum type */
263 BOOL need_value; /* TRUE requires value (name=value pair format)
264 FALSE is a singleton */
266 static env_mail_type_t env_mail_type_list[] = {
267 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
268 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
269 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
271 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
273 { US"RET", ENV_MAIL_OPT_RET, TRUE },
274 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
276 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
278 /* keep this the last entry */
279 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
282 /* When reading SMTP from a remote host, we have to use our own versions of the
283 C input-reading functions, in order to be able to flush the SMTP output only
284 when about to read more data from the socket. This is the only way to get
285 optimal performance when the client is using pipelining. Flushing for every
286 command causes a separate packet and reply packet each time; saving all the
287 responses up (when pipelining) combines them into one packet and one response.
289 For simplicity, these functions are used for *all* SMTP input, not only when
290 receiving over a socket. However, after setting up a secure socket (SSL), input
291 is read via the OpenSSL library, and another set of functions is used instead
294 These functions are set in the receive_getc etc. variables and called with the
295 same interface as the C functions. However, since there can only ever be
296 one incoming SMTP call, we just use a single buffer and flags. There is no need
297 to implement a complicated private FILE-like structure.*/
299 static uschar *smtp_inbuffer;
300 static uschar *smtp_inptr;
301 static uschar *smtp_inend;
302 static int smtp_had_eof;
303 static int smtp_had_error;
306 /* forward declarations */
307 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
308 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
309 static void smtp_quit_handler(uschar **, uschar **);
310 static void smtp_rset_handler(void);
312 /*************************************************
313 * Recheck synchronization *
314 *************************************************/
316 /* Synchronization checks can never be perfect because a packet may be on its
317 way but not arrived when the check is done. Such checks can in any case only be
318 done when TLS is not in use. Normally, the checks happen when commands are
319 read: Exim ensures that there is no more input in the input buffer. In normal
320 cases, the response to the command will be fast, and there is no further check.
322 However, for some commands an ACL is run, and that can include delays. In those
323 cases, it is useful to do another check on the input just before sending the
324 response. This also applies at the start of a connection. This function does
325 that check by means of the select() function, as long as the facility is not
326 disabled or inappropriate. A failure of select() is ignored.
328 When there is unwanted input, we read it so that it appears in the log of the
332 Returns: TRUE if all is well; FALSE if there is input pending
340 struct timeval tzero;
342 if (!smtp_enforce_sync || sender_host_address == NULL ||
343 sender_host_notsocket || tls_in.active >= 0)
346 fd = fileno(smtp_in);
351 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
353 if (rc <= 0) return TRUE; /* Not ready to read */
354 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
355 if (rc < 0) return TRUE; /* End of file or error */
358 rc = smtp_inend - smtp_inptr;
359 if (rc > 150) rc = 150;
366 /*************************************************
367 * Log incomplete transactions *
368 *************************************************/
370 /* This function is called after a transaction has been aborted by RSET, QUIT,
371 connection drops or other errors. It logs the envelope information received
372 so far in order to preserve address verification attempts.
374 Argument: string to indicate what aborted the transaction
379 incomplete_transaction_log(uschar *what)
381 if (sender_address == NULL || /* No transaction in progress */
382 !LOGGING(smtp_incomplete_transaction))
385 /* Build list of recipients for logging */
387 if (recipients_count > 0)
390 raw_recipients = store_get(recipients_count * sizeof(uschar *));
391 for (i = 0; i < recipients_count; i++)
392 raw_recipients[i] = recipients_list[i].address;
393 raw_recipients_count = recipients_count;
396 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
397 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
403 /*************************************************
404 * SMTP version of getc() *
405 *************************************************/
407 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
408 it flushes the output, and refills the buffer, with a timeout. The signal
409 handler is set appropriately by the calling function. This function is not used
410 after a connection has negotiated itself into an TLS/SSL state.
412 Arguments: lim Maximum amount to read/buffer
413 Returns: the next character or EOF
417 smtp_getc(unsigned lim)
419 if (smtp_inptr >= smtp_inend)
422 if (!smtp_out) return EOF;
424 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
426 /* Limit amount read, so non-message data is not fed to DKIM */
428 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE, lim));
433 /* Must put the error text in fixed store, because this might be during
434 header reading, where it releases unused store above the header. */
437 smtp_had_error = save_errno;
438 smtp_read_error = string_copy_malloc(
439 string_sprintf(" (error: %s)", strerror(save_errno)));
441 else smtp_had_eof = 1;
445 dkim_exim_verify_feed(smtp_inbuffer, rc);
447 smtp_inend = smtp_inbuffer + rc;
448 smtp_inptr = smtp_inbuffer;
450 return *smtp_inptr++;
457 int n = smtp_inend - smtp_inptr;
459 dkim_exim_verify_feed(smtp_inptr, n);
464 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
465 previous BDAT chunk and getting new ones when we run out. Uses the
466 underlying smtp_getc or tls_getc both for that and for getting the
467 (buffered) data byte. EOD signals (an expected) no further data.
468 ERR signals a protocol error, and EOF a closed input stream.
470 Called from read_bdat_smtp() in receive.c for the message body, but also
471 by the headers read loop in receive_msg(); manipulates chunking_state
472 to handle the BDAT command/response.
473 Placed here due to the correlation with the above smtp_getc(), which it wraps,
474 and also by the need to do smtp command/response handling.
476 Arguments: lim (ignored)
477 Returns: the next character or ERR, EOD or EOF
481 bdat_getc(unsigned lim)
483 uschar * user_msg = NULL;
492 if (chunking_data_left > 0)
493 return lwr_receive_getc(chunking_data_left--);
495 receive_getc = lwr_receive_getc;
496 receive_ungetc = lwr_receive_ungetc;
498 dkim_save = dkim_collect_input;
499 dkim_collect_input = FALSE;
502 /* Unless PIPELINING was offered, there should be no next command
503 until after we ack that chunk */
505 if (!pipelining_advertised && !check_sync())
507 incomplete_transaction_log(US"sync failure");
508 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
509 "(next input sent too soon: pipelining was not advertised): "
510 "rejected \"%s\" %s next input=\"%s\"",
511 smtp_cmd_buffer, host_and_ident(TRUE),
512 string_printing(smtp_inptr));
513 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
514 US"SMTP synchronization error");
515 goto repeat_until_rset;
518 /* If not the last, ack the received chunk. The last response is delayed
519 until after the data ACL decides on it */
521 if (chunking_state == CHUNKING_LAST)
524 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
529 smtp_printf("250 %u byte chunk received\r\n", chunking_datasize);
530 chunking_state = CHUNKING_OFFERED;
531 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
533 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
534 QUIT, RSET or NOOP but handling them seems obvious */
537 switch(smtp_read_command(TRUE, 1))
540 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
541 US"only BDAT permissible after non-LAST BDAT");
544 switch(smtp_read_command(TRUE, 1))
546 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
547 case EOF_CMD: return EOF;
548 case RSET_CMD: smtp_rset_handler(); return ERR;
549 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
550 US"only RSET accepted now") > 0)
552 goto repeat_until_rset;
556 smtp_quit_handler(&user_msg, &log_msg);
567 smtp_printf("250 OK\r\n");
574 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
576 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
577 US"missing size for BDAT command");
580 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
581 ? CHUNKING_LAST : CHUNKING_ACTIVE;
582 chunking_data_left = chunking_datasize;
583 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
584 (int)chunking_state, chunking_data_left);
586 if (chunking_datasize == 0)
587 if (chunking_state == CHUNKING_LAST)
591 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
592 US"zero size for BDAT command");
593 goto repeat_until_rset;
596 receive_getc = bdat_getc;
597 receive_ungetc = bdat_ungetc;
599 dkim_collect_input = dkim_save;
601 break; /* to top of main loop */
608 bdat_flush_data(void)
610 while (chunking_data_left > 0)
611 if (lwr_receive_getc(chunking_data_left--) < 0)
614 receive_getc = lwr_receive_getc;
615 receive_ungetc = lwr_receive_ungetc;
617 if (chunking_state != CHUNKING_LAST)
619 chunking_state = CHUNKING_OFFERED;
620 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
627 /*************************************************
628 * SMTP version of ungetc() *
629 *************************************************/
631 /* Puts a character back in the input buffer. Only ever
637 Returns: the character
651 chunking_data_left++;
652 return lwr_receive_ungetc(ch);
657 /*************************************************
658 * SMTP version of feof() *
659 *************************************************/
661 /* Tests for a previous EOF
664 Returns: non-zero if the eof flag is set
676 /*************************************************
677 * SMTP version of ferror() *
678 *************************************************/
680 /* Tests for a previous read error, and returns with errno
681 restored to what it was when the error was detected.
684 Returns: non-zero if the error flag is set
690 errno = smtp_had_error;
691 return smtp_had_error;
696 /*************************************************
697 * Test for characters in the SMTP buffer *
698 *************************************************/
700 /* Used at the end of a message
709 return smtp_inptr < smtp_inend;
714 /*************************************************
715 * Write formatted string to SMTP channel *
716 *************************************************/
718 /* This is a separate function so that we don't have to repeat everything for
719 TLS support or debugging. It is global so that the daemon and the
720 authentication functions can use it. It does not return any error indication,
721 because major problems such as dropped connections won't show up till an output
722 flush for non-TLS connections. The smtp_fflush() function is available for
723 checking that: for convenience, TLS output errors are remembered here so that
724 they are also picked up later by smtp_fflush().
728 ... optional arguments
734 smtp_printf(const char *format, ...)
738 va_start(ap, format);
739 smtp_vprintf(format, ap);
743 /* This is split off so that verify.c:respond_printf() can, in effect, call
744 smtp_printf(), bearing in mind that in C a vararg function can't directly
745 call another vararg function, only a function which accepts a va_list. */
748 smtp_vprintf(const char *format, va_list ap)
752 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
756 void *reset_point = store_get(0);
757 uschar *msg_copy, *cr, *end;
758 msg_copy = string_copy(big_buffer);
759 end = msg_copy + Ustrlen(msg_copy);
760 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
761 memmove(cr, cr + 1, (end--) - cr);
762 debug_printf("SMTP>> %s", msg_copy);
763 store_reset(reset_point);
768 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
769 smtp_closedown(US"Unexpected error");
770 exim_exit(EXIT_FAILURE);
773 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
774 have had the same. Note: this code is also present in smtp_respond(). It would
775 be tidier to have it only in one place, but when it was added, it was easier to
776 do it that way, so as not to have to mess with the code for the RCPT command,
777 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
779 if (rcpt_in_progress)
781 if (rcpt_smtp_response == NULL)
782 rcpt_smtp_response = string_copy(big_buffer);
783 else if (rcpt_smtp_response_same &&
784 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
785 rcpt_smtp_response_same = FALSE;
786 rcpt_in_progress = FALSE;
789 /* Now write the string */
792 if (tls_in.active >= 0)
794 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
795 smtp_write_error = -1;
800 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
805 /*************************************************
806 * Flush SMTP out and check for error *
807 *************************************************/
809 /* This function isn't currently used within Exim (it detects errors when it
810 tries to read the next SMTP input), but is available for use in local_scan().
811 For non-TLS connections, it flushes the output and checks for errors. For
812 TLS-connections, it checks for a previously-detected TLS write error.
815 Returns: 0 for no error; -1 after an error
821 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
822 return smtp_write_error;
827 /*************************************************
828 * SMTP command read timeout *
829 *************************************************/
831 /* Signal handler for timing out incoming SMTP commands. This attempts to
834 Argument: signal number (SIGALRM)
839 command_timeout_handler(int sig)
841 sig = sig; /* Keep picky compilers happy */
842 log_write(L_lost_incoming_connection,
843 LOG_MAIN, "SMTP command timeout on%s connection from %s",
844 (tls_in.active >= 0)? " TLS" : "",
845 host_and_ident(FALSE));
846 if (smtp_batched_input)
847 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
848 smtp_notquit_exit(US"command-timeout", US"421",
849 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
850 exim_exit(EXIT_FAILURE);
855 /*************************************************
857 *************************************************/
859 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
861 Argument: signal number (SIGTERM)
866 command_sigterm_handler(int sig)
868 sig = sig; /* Keep picky compilers happy */
869 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
870 if (smtp_batched_input)
871 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
872 smtp_notquit_exit(US"signal-exit", US"421",
873 US"%s: Service not available - closing connection", smtp_active_hostname);
874 exim_exit(EXIT_FAILURE);
881 /*************************************************
882 * Restore socket timeout to previous value *
883 *************************************************/
884 /* If the previous value was successfully retrieved, restore
885 it before returning control to the non-proxy routines
887 Arguments: fd - File descriptor for input
888 get_ok - Successfully retrieved previous values
889 tvtmp - Time struct with previous values
890 vslen - Length of time struct
894 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
897 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
900 /*************************************************
901 * Check if host is required proxy host *
902 *************************************************/
903 /* The function determines if inbound host will be a regular smtp host
904 or if it is configured that it must use Proxy Protocol. A local
912 check_proxy_protocol_host()
916 if ( sender_host_address
917 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
918 sender_host_address, NULL)) == OK)
921 debug_printf("Detected proxy protocol configured host\n");
922 proxy_session = TRUE;
924 return proxy_session;
928 /*************************************************
929 * Read data until newline or end of buffer *
930 *************************************************/
931 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
932 read an entire buffer and assume there will be nothing past a proxy protocol
933 header. Our approach normally is to use stdio, but again that relies upon
934 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
935 reading _nothing_ before client TLS handshake. So we don't want to use the
936 usual buffering reads which may read enough to block TLS starting.
938 So unfortunately we're down to "read one byte at a time, with a syscall each,
939 and expect a little overhead", for all proxy-opened connections which are v1,
940 just to handle the TLS-on-connect case. Since SSL functions wrap the
941 underlying fd, we can't assume that we can feed them any already-read content.
943 We need to know where to read to, the max capacity, and we'll read until we
944 get a CR and one more character. Let the caller scream if it's CR+!LF.
946 Return the amount read.
950 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
952 uschar *to = base + already;
958 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
959 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
961 cr = memchr(base, '\r', already);
964 if ((cr - base) < already - 1)
966 /* \r and presumed \n already within what we have; probably not
967 actually proxy protocol, but abort cleanly. */
970 /* \r is last character read, just need one more. */
976 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
988 /* reached end without having room for a final newline, abort */
993 /*************************************************
994 * Setup host for proxy protocol *
995 *************************************************/
996 /* The function configures the connection based on a header from the
997 inbound host to use Proxy Protocol. The specification is very exact
998 so exit with an error if do not find the exact required pieces. This
999 includes an incorrect number of spaces separating args.
1002 Returns: Boolean success
1006 setup_proxy_protocol_host()
1018 struct { /* TCP/UDP over IPv4, len = 12 */
1024 struct { /* TCP/UDP over IPv6, len = 36 */
1025 uint8_t src_addr[16];
1026 uint8_t dst_addr[16];
1030 struct { /* AF_UNIX sockets, len = 216 */
1031 uschar src_addr[108];
1032 uschar dst_addr[108];
1038 /* Temp variables used in PPv2 address:port parsing */
1040 char tmpip[INET_ADDRSTRLEN];
1041 struct sockaddr_in tmpaddr;
1042 char tmpip6[INET6_ADDRSTRLEN];
1043 struct sockaddr_in6 tmpaddr6;
1045 /* We can't read "all data until end" because while SMTP is
1046 server-speaks-first, the TLS handshake is client-speaks-first, so for
1047 TLS-on-connect ports the proxy protocol header will usually be immediately
1048 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1049 reinject data for reading by those. So instead we first read "enough to be
1050 safely read within the header, and figure out how much more to read".
1051 For v1 we will later read to the end-of-line, for v2 we will read based upon
1054 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1055 data is needed total. For v1, where the line looks like:
1056 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1058 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1059 We seem to support that. So, if we read 14 octets then we can tell if we're
1060 v2 or v1. If we're v1, we can continue reading as normal.
1062 If we're v2, we can't slurp up the entire header. We need the length in the
1063 15th & 16th octets, then to read everything after that.
1065 So to safely handle v1 and v2, with client-sent-first supported correctly,
1066 we have to do a minimum of 3 read calls, not 1. Eww.
1069 #define PROXY_INITIAL_READ 14
1070 #define PROXY_V2_HEADER_SIZE 16
1071 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1072 # error Code bug in sizes of data to read for proxy usage
1077 int fd = fileno(smtp_in);
1078 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1079 uschar * iptype; /* To display debug info */
1081 struct timeval tvtmp;
1082 socklen_t vslen = sizeof(struct timeval);
1085 /* Save current socket timeout values */
1086 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1088 /* Proxy Protocol host must send header within a short time
1089 (default 3 seconds) or it's considered invalid */
1090 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1091 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1092 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1097 /* The inbound host was declared to be a Proxy Protocol host, so
1098 don't do a PEEK into the data, actually slurp up enough to be
1099 "safe". Can't take it all because TLS-on-connect clients follow
1100 immediately with TLS handshake. */
1101 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1103 while (ret == -1 && errno == EINTR);
1108 /* For v2, handle reading the length, and then the rest. */
1109 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1114 /* First get the length fields. */
1117 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1118 } while (retmore == -1 && errno == EINTR);
1123 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1125 /* May 2014: haproxy combined the version and command into one byte to
1126 allow two full bytes for the length field in order to proxy SSL
1127 connections. SSL Proxy is not supported in this version of Exim, but
1128 must still separate values here. */
1132 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1136 /* The v2 header will always be 16 bytes per the spec. */
1137 size = 16 + ntohs(hdr.v2.len);
1138 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1139 size, (int)sizeof(hdr));
1141 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1142 amount that we need. Double-check that the size is not unreasonable, then
1144 if (size > sizeof(hdr))
1146 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1154 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1155 } while (retmore == -1 && errno == EINTR);
1159 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1160 } while (ret < size);
1162 } /* end scope for getting rest of data for v2 */
1164 /* At this point: if PROXYv2, we've read the exact size required for all data;
1165 if PROXYv1 then we've read "less than required for any valid line" and should
1168 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1170 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1174 case 0x01: /* PROXY command */
1177 case 0x11: /* TCPv4 address type */
1179 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1180 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1181 if (!string_is_ip_address(US tmpip, NULL))
1183 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1186 proxy_local_address = sender_host_address;
1187 sender_host_address = string_copy(US tmpip);
1188 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1189 proxy_local_port = sender_host_port;
1190 sender_host_port = tmpport;
1191 /* Save dest ip/port */
1192 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1193 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1194 if (!string_is_ip_address(US tmpip, NULL))
1196 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1199 proxy_external_address = string_copy(US tmpip);
1200 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1201 proxy_external_port = tmpport;
1203 case 0x21: /* TCPv6 address type */
1205 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1206 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1207 if (!string_is_ip_address(US tmpip6, NULL))
1209 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1212 proxy_local_address = sender_host_address;
1213 sender_host_address = string_copy(US tmpip6);
1214 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1215 proxy_local_port = sender_host_port;
1216 sender_host_port = tmpport;
1217 /* Save dest ip/port */
1218 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1219 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1220 if (!string_is_ip_address(US tmpip6, NULL))
1222 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1225 proxy_external_address = string_copy(US tmpip6);
1226 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1227 proxy_external_port = tmpport;
1231 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1235 /* Unsupported protocol, keep local connection address */
1237 case 0x00: /* LOCAL command */
1238 /* Keep local connection address for LOCAL */
1243 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1247 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1251 uschar *sp; /* Utility variables follow */
1256 /* get the rest of the line */
1257 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1262 p = string_copy(hdr.v1.line);
1263 end = memchr(p, '\r', ret - 1);
1265 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1267 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1270 *end = '\0'; /* Terminate the string */
1271 size = end + 2 - p; /* Skip header + CRLF */
1272 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1273 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1274 /* Step through the string looking for the required fields. Ensure
1275 strict adherence to required formatting, exit for any error. */
1277 if (!isspace(*(p++)))
1279 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1282 if (!Ustrncmp(p, CCS"TCP4", 4))
1284 else if (!Ustrncmp(p,CCS"TCP6", 4))
1286 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1288 iptype = US"Unknown";
1293 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1297 p += Ustrlen(iptype);
1298 if (!isspace(*(p++)))
1300 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1303 /* Find the end of the arg */
1304 if ((sp = Ustrchr(p, ' ')) == NULL)
1307 debug_printf("Did not find proxied src %s\n", iptype);
1311 if(!string_is_ip_address(p, NULL))
1314 debug_printf("Proxied src arg is not an %s address\n", iptype);
1317 proxy_local_address = sender_host_address;
1318 sender_host_address = p;
1320 if ((sp = Ustrchr(p, ' ')) == NULL)
1323 debug_printf("Did not find proxy dest %s\n", iptype);
1327 if(!string_is_ip_address(p, NULL))
1330 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1333 proxy_external_address = p;
1335 if ((sp = Ustrchr(p, ' ')) == NULL)
1337 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1341 tmp_port = strtol(CCS p, &endc, 10);
1342 if (*endc || tmp_port == 0)
1345 debug_printf("Proxied src port '%s' not an integer\n", p);
1348 proxy_local_port = sender_host_port;
1349 sender_host_port = tmp_port;
1351 if ((sp = Ustrchr(p, '\0')) == NULL)
1353 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1356 tmp_port = strtol(CCS p, &endc, 10);
1357 if (*endc || tmp_port == 0)
1360 debug_printf("Proxy dest port '%s' not an integer\n", p);
1363 proxy_external_port = tmp_port;
1364 /* Already checked for /r /n above. Good V1 header received. */
1368 /* Wrong protocol */
1369 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1370 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1376 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1377 yield = proxy_session;
1379 /* Don't flush any potential buffer contents. Any input on proxyfail
1380 should cause a synchronization failure */
1383 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1388 sender_host_name = NULL;
1389 (void) host_name_lookup();
1390 host_build_sender_fullhost();
1394 proxy_session_failed = TRUE;
1396 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1403 /*************************************************
1404 * Read one command line *
1405 *************************************************/
1407 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1408 There are sites that don't do this, and in any case internal SMTP probably
1409 should check only for LF. Consequently, we check here for LF only. The line
1410 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1411 an unknown command. The command is read into the global smtp_cmd_buffer so that
1412 it is available via $smtp_command.
1414 The character reading routine sets up a timeout for each block actually read
1415 from the input (which may contain more than one command). We set up a special
1416 signal handler that closes down the session on a timeout. Control does not
1417 return when it runs.
1420 check_sync if TRUE, check synchronization rules if global option is TRUE
1421 buffer_lim maximum to buffer in lower layer
1423 Returns: a code identifying the command (enumerated above)
1427 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1432 BOOL hadnull = FALSE;
1434 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1436 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1438 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1440 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1448 smtp_cmd_buffer[ptr++] = c;
1451 receive_linecount++; /* For BSMTP errors */
1452 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1454 /* If hit end of file, return pseudo EOF command. Whether we have a
1455 part-line already read doesn't matter, since this is an error state. */
1457 if (c == EOF) return EOF_CMD;
1459 /* Remove any CR and white space at the end of the line, and terminate the
1462 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1463 smtp_cmd_buffer[ptr] = 0;
1465 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1467 /* NULLs are not allowed in SMTP commands */
1469 if (hadnull) return BADCHAR_CMD;
1471 /* Scan command list and return identity, having set the data pointer
1472 to the start of the actual data characters. Check for SMTP synchronization
1475 for (p = cmd_list; p < cmd_list_end; p++)
1477 #ifdef SUPPORT_PROXY
1478 /* Only allow QUIT command if Proxy Protocol parsing failed */
1479 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1483 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1484 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1485 || smtp_cmd_buffer[p->len] == 0
1486 || smtp_cmd_buffer[p->len] == ' '
1489 if (smtp_inptr < smtp_inend && /* Outstanding input */
1490 p->cmd < sync_cmd_limit && /* Command should sync */
1491 check_sync && /* Local flag set */
1492 smtp_enforce_sync && /* Global flag set */
1493 sender_host_address != NULL && /* Not local input */
1494 !sender_host_notsocket) /* Really is a socket */
1497 /* The variables $smtp_command and $smtp_command_argument point into the
1498 unmodified input buffer. A copy of the latter is taken for actual
1499 processing, so that it can be chopped up into separate parts if necessary,
1500 for example, when processing a MAIL command options such as SIZE that can
1501 follow the sender address. */
1503 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1504 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1505 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1506 smtp_cmd_data = smtp_data_buffer;
1508 /* Count non-mail commands from those hosts that are controlled in this
1509 way. The default is all hosts. We don't waste effort checking the list
1510 until we get a non-mail command, but then cache the result to save checking
1511 again. If there's a DEFER while checking the host, assume it's in the list.
1513 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1514 start of each incoming message by fiddling with the value in the table. */
1516 if (!p->is_mail_cmd)
1518 if (count_nonmail == TRUE_UNSET) count_nonmail =
1519 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1520 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1521 return TOO_MANY_NONMAIL_CMD;
1524 /* If there is data for a command that does not expect it, generate the
1527 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1531 #ifdef SUPPORT_PROXY
1532 /* Only allow QUIT command if Proxy Protocol parsing failed */
1533 if (proxy_session && proxy_session_failed)
1534 return PROXY_FAIL_IGNORE_CMD;
1537 /* Enforce synchronization for unknown commands */
1539 if (smtp_inptr < smtp_inend && /* Outstanding input */
1540 check_sync && /* Local flag set */
1541 smtp_enforce_sync && /* Global flag set */
1542 sender_host_address != NULL && /* Not local input */
1543 !sender_host_notsocket) /* Really is a socket */
1551 /*************************************************
1552 * Forced closedown of call *
1553 *************************************************/
1555 /* This function is called from log.c when Exim is dying because of a serious
1556 disaster, and also from some other places. If an incoming non-batched SMTP
1557 channel is open, it swallows the rest of the incoming message if in the DATA
1558 phase, sends the reply string, and gives an error to all subsequent commands
1559 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1563 message SMTP reply string to send, excluding the code
1569 smtp_closedown(uschar *message)
1571 if (smtp_in == NULL || smtp_batched_input) return;
1572 receive_swallow_smtp();
1573 smtp_printf("421 %s\r\n", message);
1575 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1581 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1586 smtp_printf("250 Reset OK\r\n");
1590 smtp_printf("421 %s\r\n", message);
1598 /*************************************************
1599 * Set up connection info for logging *
1600 *************************************************/
1602 /* This function is called when logging information about an SMTP connection.
1603 It sets up appropriate source information, depending on the type of connection.
1604 If sender_fullhost is NULL, we are at a very early stage of the connection;
1605 just use the IP address.
1608 Returns: a string describing the connection
1612 smtp_get_connection_info(void)
1614 const uschar * hostname = sender_fullhost
1615 ? sender_fullhost : sender_host_address;
1618 return string_sprintf("SMTP connection from %s", hostname);
1620 if (sender_host_unknown || sender_host_notsocket)
1621 return string_sprintf("SMTP connection from %s", sender_ident);
1624 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1626 if (LOGGING(incoming_interface) && interface_address != NULL)
1627 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1628 interface_address, interface_port);
1630 return string_sprintf("SMTP connection from %s", hostname);
1636 /* Append TLS-related information to a log line
1639 s String under construction: allocated string to extend, or NULL
1640 sizep Pointer to current allocation size (update on return), or NULL
1641 ptrp Pointer to index for new entries in string (update on return), or NULL
1643 Returns: Allocated string or NULL
1646 s_tlslog(uschar * s, int * sizep, int * ptrp)
1648 int size = sizep ? *sizep : 0;
1649 int ptr = ptrp ? *ptrp : 0;
1651 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1652 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1653 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1654 s = string_append(s, &size, &ptr, 2, US" CV=",
1655 tls_in.certificate_verified? "yes":"no");
1656 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1657 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1658 string_printing(tls_in.peerdn), US"\"");
1659 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1660 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1661 string_printing(tls_in.sni), US"\"");
1666 if (sizep) *sizep = size;
1667 if (ptrp) *ptrp = ptr;
1673 /*************************************************
1674 * Log lack of MAIL if so configured *
1675 *************************************************/
1677 /* This function is called when an SMTP session ends. If the log selector
1678 smtp_no_mail is set, write a log line giving some details of what has happened
1679 in the SMTP session.
1686 smtp_log_no_mail(void)
1691 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1697 if (sender_host_authenticated != NULL)
1699 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1700 if (authenticated_id != NULL)
1701 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1705 s = s_tlslog(s, &size, &ptr);
1708 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1709 US" C=..." : US" C=";
1710 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1712 if (smtp_connection_had[i] != SCH_NONE)
1714 s = string_append(s, &size, &ptr, 2, sep,
1715 smtp_names[smtp_connection_had[i]]);
1720 for (i = 0; i < smtp_ch_index; i++)
1722 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1726 if (s != NULL) s[ptr] = 0; else s = US"";
1727 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1728 host_and_ident(FALSE),
1729 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1735 /*************************************************
1736 * Check HELO line and set sender_helo_name *
1737 *************************************************/
1739 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1740 the domain name of the sending host, or an ip literal in square brackets. The
1741 argument is placed in sender_helo_name, which is in malloc store, because it
1742 must persist over multiple incoming messages. If helo_accept_junk is set, this
1743 host is permitted to send any old junk (needed for some broken hosts).
1744 Otherwise, helo_allow_chars can be used for rogue characters in general
1745 (typically people want to let in underscores).
1748 s the data portion of the line (already past any white space)
1750 Returns: TRUE or FALSE
1754 check_helo(uschar *s)
1757 uschar *end = s + Ustrlen(s);
1758 BOOL yield = helo_accept_junk;
1760 /* Discard any previous helo name */
1762 if (sender_helo_name != NULL)
1764 store_free(sender_helo_name);
1765 sender_helo_name = NULL;
1768 /* Skip tests if junk is permitted. */
1772 /* Allow the new standard form for IPv6 address literals, namely,
1773 [IPv6:....], and because someone is bound to use it, allow an equivalent
1774 IPv4 form. Allow plain addresses as well. */
1781 if (strncmpic(s, US"[IPv6:", 6) == 0)
1782 yield = (string_is_ip_address(s+6, NULL) == 6);
1783 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1784 yield = (string_is_ip_address(s+6, NULL) == 4);
1786 yield = (string_is_ip_address(s+1, NULL) != 0);
1791 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1792 that have been configured (usually underscore - sigh). */
1799 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1800 Ustrchr(helo_allow_chars, *s) == NULL)
1810 /* Save argument if OK */
1812 if (yield) sender_helo_name = string_copy_malloc(start);
1820 /*************************************************
1821 * Extract SMTP command option *
1822 *************************************************/
1824 /* This function picks the next option setting off the end of smtp_cmd_data. It
1825 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1826 things that can appear there.
1829 name point this at the name
1830 value point this at the data string
1832 Returns: TRUE if found an option
1836 extract_option(uschar **name, uschar **value)
1839 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1840 while (isspace(*v)) v--;
1842 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1844 /* Take care to not stop at a space embedded in a quoted local-part */
1846 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1853 while(isalpha(n[-1])) n--;
1854 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1855 if (!isspace(n[-1])) return FALSE;
1861 if (v == smtp_cmd_data) return FALSE;
1873 /*************************************************
1874 * Reset for new message *
1875 *************************************************/
1877 /* This function is called whenever the SMTP session is reset from
1878 within either of the setup functions.
1880 Argument: the stacking pool storage reset point
1885 smtp_reset(void *reset_point)
1887 recipients_list = NULL;
1888 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1889 raw_recipients_count = recipients_count = recipients_list_max = 0;
1890 message_linecount = 0;
1892 acl_added_headers = NULL;
1893 acl_removed_headers = NULL;
1894 queue_only_policy = FALSE;
1895 rcpt_smtp_response = NULL;
1896 rcpt_smtp_response_same = TRUE;
1897 rcpt_in_progress = FALSE;
1898 deliver_freeze = FALSE; /* Can be set by ACL */
1899 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1900 fake_response = OK; /* Can be set by ACL */
1901 #ifdef WITH_CONTENT_SCAN
1902 no_mbox_unspool = FALSE; /* Can be set by ACL */
1904 submission_mode = FALSE; /* Can be set by ACL */
1905 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1906 active_local_from_check = local_from_check; /* Can be set by ACL */
1907 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1908 sending_ip_address = NULL;
1909 return_path = sender_address = NULL;
1910 sender_data = NULL; /* Can be set by ACL */
1911 deliver_localpart_orig = NULL;
1912 deliver_domain_orig = NULL;
1913 callout_address = NULL;
1914 submission_name = NULL; /* Can be set by ACL */
1915 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1916 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1917 sender_verified_list = NULL; /* No senders verified */
1918 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1919 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1921 authenticated_sender = NULL;
1922 #ifdef EXPERIMENTAL_BRIGHTMAIL
1924 bmi_verdicts = NULL;
1926 dnslist_domain = dnslist_matched = NULL;
1927 #ifndef DISABLE_DKIM
1928 dkim_signers = NULL;
1929 dkim_disable_verify = FALSE;
1930 dkim_collect_input = FALSE;
1934 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
1935 #ifndef DISABLE_PRDR
1936 prdr_requested = FALSE;
1938 #ifdef EXPERIMENTAL_SPF
1939 spf_header_comment = NULL;
1940 spf_received = NULL;
1942 spf_smtp_comment = NULL;
1945 message_smtputf8 = FALSE;
1947 body_linecount = body_zerocount = 0;
1949 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1950 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1951 /* Note that ratelimiters_conn persists across resets. */
1953 /* Reset message ACL variables */
1957 /* The message body variables use malloc store. They may be set if this is
1958 not the first message in an SMTP session and the previous message caused them
1959 to be referenced in an ACL. */
1963 store_free(message_body);
1964 message_body = NULL;
1967 if (message_body_end)
1969 store_free(message_body_end);
1970 message_body_end = NULL;
1973 /* Warning log messages are also saved in malloc store. They are saved to avoid
1974 repetition in the same message, but it seems right to repeat them for different
1977 while (acl_warn_logged)
1979 string_item *this = acl_warn_logged;
1980 acl_warn_logged = acl_warn_logged->next;
1983 store_reset(reset_point);
1990 /*************************************************
1991 * Initialize for incoming batched SMTP message *
1992 *************************************************/
1994 /* This function is called from smtp_setup_msg() in the case when
1995 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1996 of messages in one file with SMTP commands between them. All errors must be
1997 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1998 relevant. After an error on a sender, or an invalid recipient, the remainder
1999 of the message is skipped. The value of received_protocol is already set.
2002 Returns: > 0 message successfully started (reached DATA)
2003 = 0 QUIT read or end of file reached
2004 < 0 should not occur
2008 smtp_setup_batch_msg(void)
2011 void *reset_point = store_get(0);
2013 /* Save the line count at the start of each transaction - single commands
2014 like HELO and RSET count as whole transactions. */
2016 bsmtp_transaction_linecount = receive_linecount;
2018 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2020 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2021 smtp_reset(reset_point); /* Reset for start of message */
2023 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2024 value. The values are 2 larger than the required yield of the function. */
2029 uschar *recipient = NULL;
2030 int start, end, sender_domain, recipient_domain;
2032 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2034 /* The HELO/EHLO commands set sender_address_helo if they have
2035 valid data; otherwise they are ignored, except that they do
2036 a reset of the state. */
2041 check_helo(smtp_cmd_data);
2045 cancel_cutthrough_connection(TRUE, US"RSET received");
2046 smtp_reset(reset_point);
2047 bsmtp_transaction_linecount = receive_linecount;
2051 /* The MAIL FROM command requires an address as an operand. All we
2052 do here is to parse it for syntactic correctness. The form "<>" is
2053 a special case which converts into an empty string. The start/end
2054 pointers in the original are not used further for this address, as
2055 it is the canonical extracted address which is all that is kept. */
2058 smtp_mailcmd_count++; /* Count for no-mail log */
2059 if (sender_address != NULL)
2060 /* The function moan_smtp_batch() does not return. */
2061 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2063 if (smtp_cmd_data[0] == 0)
2064 /* The function moan_smtp_batch() does not return. */
2065 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2067 /* Reset to start of message */
2069 cancel_cutthrough_connection(TRUE, US"MAIL received");
2070 smtp_reset(reset_point);
2072 /* Apply SMTP rewrite */
2074 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2075 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2076 US"", global_rewrite_rules) : smtp_cmd_data;
2078 /* Extract the address; the TRUE flag allows <> as valid */
2081 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2084 if (raw_sender == NULL)
2085 /* The function moan_smtp_batch() does not return. */
2086 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2088 sender_address = string_copy(raw_sender);
2090 /* Qualify unqualified sender addresses if permitted to do so. */
2092 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
2094 if (allow_unqualified_sender)
2096 sender_address = rewrite_address_qualify(sender_address, FALSE);
2097 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2098 "and rewritten\n", raw_sender);
2100 /* The function moan_smtp_batch() does not return. */
2101 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2107 /* The RCPT TO command requires an address as an operand. All we do
2108 here is to parse it for syntactic correctness. There may be any number
2109 of RCPT TO commands, specifying multiple senders. We build them all into
2110 a data structure that is in argc/argv format. The start/end values
2111 given by parse_extract_address are not used, as we keep only the
2112 extracted address. */
2115 if (sender_address == NULL)
2116 /* The function moan_smtp_batch() does not return. */
2117 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2119 if (smtp_cmd_data[0] == 0)
2120 /* The function moan_smtp_batch() does not return. */
2121 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
2123 /* Check maximum number allowed */
2125 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2126 /* The function moan_smtp_batch() does not return. */
2127 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2128 recipients_max_reject? "552": "452");
2130 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2131 recipient address */
2133 recipient = rewrite_existflags & rewrite_smtp
2134 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2135 global_rewrite_rules)
2138 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2139 &recipient_domain, FALSE);
2142 /* The function moan_smtp_batch() does not return. */
2143 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2145 /* If the recipient address is unqualified, qualify it if permitted. Then
2146 add it to the list of recipients. */
2148 if (recipient_domain == 0)
2150 if (allow_unqualified_recipient)
2152 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2154 recipient = rewrite_address_qualify(recipient, TRUE);
2156 /* The function moan_smtp_batch() does not return. */
2157 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
2160 receive_add_recipient(recipient, -1);
2164 /* The DATA command is legal only if it follows successful MAIL FROM
2165 and RCPT TO commands. This function is complete when a valid DATA
2166 command is encountered. */
2169 if (sender_address == NULL || recipients_count <= 0)
2171 /* The function moan_smtp_batch() does not return. */
2172 if (sender_address == NULL)
2173 moan_smtp_batch(smtp_cmd_buffer,
2174 "503 MAIL FROM:<sender> command must precede DATA");
2176 moan_smtp_batch(smtp_cmd_buffer,
2177 "503 RCPT TO:<recipient> must precede DATA");
2181 done = 3; /* DATA successfully achieved */
2182 message_ended = END_NOTENDED; /* Indicate in middle of message */
2187 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2194 bsmtp_transaction_linecount = receive_linecount;
2205 /* The function moan_smtp_batch() does not return. */
2206 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2211 /* The function moan_smtp_batch() does not return. */
2212 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2217 /* The function moan_smtp_batch() does not return. */
2218 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2223 return done - 2; /* Convert yield values */
2230 smtp_log_tls_fail(uschar * errstr)
2232 uschar * conn_info = smtp_get_connection_info();
2234 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2235 /* I'd like to get separated H= here, but too hard for now */
2237 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2242 /*************************************************
2243 * Start an SMTP session *
2244 *************************************************/
2246 /* This function is called at the start of an SMTP session. Thereafter,
2247 smtp_setup_msg() is called to initiate each separate message. This
2248 function does host-specific testing, and outputs the banner line.
2251 Returns: FALSE if the session can not continue; something has
2252 gone wrong, or the connection to the host is blocked
2256 smtp_start_session(void)
2260 uschar *user_msg, *log_msg;
2264 smtp_connection_start = time(NULL);
2265 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2266 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2269 /* Default values for certain variables */
2271 helo_seen = esmtp = helo_accept_junk = FALSE;
2272 smtp_mailcmd_count = 0;
2273 count_nonmail = TRUE_UNSET;
2274 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2275 smtp_delay_mail = smtp_rlm_base;
2276 auth_advertised = FALSE;
2277 pipelining_advertised = FALSE;
2278 pipelining_enable = TRUE;
2279 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2280 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2282 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2283 authentication settings from -oMaa to remain in force. */
2285 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2286 authenticated_by = NULL;
2289 tls_in.cipher = tls_in.peerdn = NULL;
2290 tls_in.ourcert = tls_in.peercert = NULL;
2292 tls_in.ocsp = OCSP_NOT_REQ;
2293 tls_advertised = FALSE;
2295 dsn_advertised = FALSE;
2297 smtputf8_advertised = FALSE;
2300 /* Reset ACL connection variables */
2304 /* Allow for trailing 0 in the command and data buffers. */
2306 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2307 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2308 "malloc() failed for SMTP command buffer");
2310 smtp_cmd_buffer[0] = 0;
2311 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2313 /* For batched input, the protocol setting can be overridden from the
2314 command line by a trusted caller. */
2316 if (smtp_batched_input)
2318 if (!received_protocol) received_protocol = US"local-bsmtp";
2321 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2322 reset later if any of EHLO/AUTH/STARTTLS are received. */
2326 (sender_host_address ? protocols : protocols_local) [pnormal];
2328 /* Set up the buffer for inputting using direct read() calls, and arrange to
2329 call the local functions instead of the standard C ones. */
2331 if (!(smtp_inbuffer = (uschar *)malloc(IN_BUFFER_SIZE)))
2332 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2334 receive_getc = smtp_getc;
2335 receive_get_cache = smtp_get_cache;
2336 receive_ungetc = smtp_ungetc;
2337 receive_feof = smtp_feof;
2338 receive_ferror = smtp_ferror;
2339 receive_smtp_buffered = smtp_buffered;
2340 smtp_inptr = smtp_inend = smtp_inbuffer;
2341 smtp_had_eof = smtp_had_error = 0;
2343 /* Set up the message size limit; this may be host-specific */
2345 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2346 if (expand_string_message != NULL)
2348 if (thismessage_size_limit == -1)
2349 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2350 "%s", expand_string_message);
2352 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2353 "%s", expand_string_message);
2354 smtp_closedown(US"Temporary local problem - please try later");
2358 /* When a message is input locally via the -bs or -bS options, sender_host_
2359 unknown is set unless -oMa was used to force an IP address, in which case it
2360 is checked like a real remote connection. When -bs is used from inetd, this
2361 flag is not set, causing the sending host to be checked. The code that deals
2362 with IP source routing (if configured) is never required for -bs or -bS and
2363 the flag sender_host_notsocket is used to suppress it.
2365 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2366 reserve for certain hosts and/or networks. */
2368 if (!sender_host_unknown)
2371 BOOL reserved_host = FALSE;
2373 /* Look up IP options (source routing info) on the socket if this is not an
2374 -oMa "host", and if any are found, log them and drop the connection.
2376 Linux (and others now, see below) is different to everyone else, so there
2377 has to be some conditional compilation here. Versions of Linux before 2.1.15
2378 used a structure whose name was "options". Somebody finally realized that
2379 this name was silly, and it got changed to "ip_options". I use the
2380 newer name here, but there is a fudge in the script that sets up os.h
2381 to define a macro in older Linux systems.
2383 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2384 glibc 2, which has chosen ip_opts for the structure name. This is now
2385 really a glibc thing rather than a Linux thing, so the condition name
2386 has been changed to reflect this. It is relevant also to GNU/Hurd.
2388 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2389 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2390 a special macro defined in the os.h file.
2392 Some DGUX versions on older hardware appear not to support IP options at
2393 all, so there is now a general macro which can be set to cut out this
2396 How to do this properly in IPv6 is not yet known. */
2398 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2400 #ifdef GLIBC_IP_OPTIONS
2401 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2406 #elif defined DARWIN_IP_OPTIONS
2412 if (!host_checking && !sender_host_notsocket)
2415 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2416 struct ip_options *ipopt = store_get(optlen);
2418 struct ip_opts ipoptblock;
2419 struct ip_opts *ipopt = &ipoptblock;
2420 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2422 struct ipoption ipoptblock;
2423 struct ipoption *ipopt = &ipoptblock;
2424 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2427 /* Occasional genuine failures of getsockopt() have been seen - for
2428 example, "reset by peer". Therefore, just log and give up on this
2429 call, unless the error is ENOPROTOOPT. This error is given by systems
2430 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2431 of writing. So for that error, carry on - we just can't do an IP options
2434 DEBUG(D_receive) debug_printf("checking for IP options\n");
2436 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2439 if (errno != ENOPROTOOPT)
2441 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2442 host_and_ident(FALSE), strerror(errno));
2443 smtp_printf("451 SMTP service not available\r\n");
2448 /* Deal with any IP options that are set. On the systems I have looked at,
2449 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2450 more logging data than will fit in big_buffer. Nevertheless, after somebody
2451 questioned this code, I've added in some paranoid checking. */
2453 else if (optlen > 0)
2455 uschar *p = big_buffer;
2456 uschar *pend = big_buffer + big_buffer_size;
2457 uschar *opt, *adptr;
2459 struct in_addr addr;
2462 uschar *optstart = (uschar *)(ipopt->__data);
2464 uschar *optstart = (uschar *)(ipopt->ip_opts);
2466 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2469 DEBUG(D_receive) debug_printf("IP options exist\n");
2471 Ustrcpy(p, "IP options on incoming call:");
2474 for (opt = optstart; opt != NULL &&
2475 opt < (uschar *)(ipopt) + optlen;)
2489 if (!string_format(p, pend-p, " %s [@%s",
2490 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2492 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2494 inet_ntoa(ipopt->ip_dst)))
2496 inet_ntoa(ipopt->ipopt_dst)))
2504 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2506 while (optcount-- > 0)
2508 memcpy(&addr, adptr, sizeof(addr));
2509 if (!string_format(p, pend - p - 1, "%s%s",
2510 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2516 adptr += sizeof(struct in_addr);
2525 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2528 for (i = 0; i < opt[1]; i++)
2530 sprintf(CS p, "%2.2x ", opt[i]);
2541 log_write(0, LOG_MAIN, "%s", big_buffer);
2543 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2545 log_write(0, LOG_MAIN|LOG_REJECT,
2546 "connection from %s refused (IP options)", host_and_ident(FALSE));
2548 smtp_printf("554 SMTP service not available\r\n");
2552 /* Length of options = 0 => there are no options */
2554 else DEBUG(D_receive) debug_printf("no IP options found\n");
2556 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2558 /* Set keep-alive in socket options. The option is on by default. This
2559 setting is an attempt to get rid of some hanging connections that stick in
2560 read() when the remote end (usually a dialup) goes away. */
2562 if (smtp_accept_keepalive && !sender_host_notsocket)
2563 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2565 /* If the current host matches host_lookup, set the name by doing a
2566 reverse lookup. On failure, sender_host_name will be NULL and
2567 host_lookup_failed will be TRUE. This may or may not be serious - optional
2570 if (verify_check_host(&host_lookup) == OK)
2572 (void)host_name_lookup();
2573 host_build_sender_fullhost();
2576 /* Delay this until we have the full name, if it is looked up. */
2578 set_process_info("handling incoming connection from %s",
2579 host_and_ident(FALSE));
2581 /* Expand smtp_receive_timeout, if needed */
2583 if (smtp_receive_timeout_s)
2586 if ( !(exp = expand_string(smtp_receive_timeout_s))
2588 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2590 log_write(0, LOG_MAIN|LOG_PANIC,
2591 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2594 /* Test for explicit connection rejection */
2596 if (verify_check_host(&host_reject_connection) == OK)
2598 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2599 "from %s (host_reject_connection)", host_and_ident(FALSE));
2600 smtp_printf("554 SMTP service not available\r\n");
2604 /* Test with TCP Wrappers if so configured. There is a problem in that
2605 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2606 such as disks dying. In these cases, it is desirable to reject with a 4xx
2607 error instead of a 5xx error. There isn't a "right" way to detect such
2608 problems. The following kludge is used: errno is zeroed before calling
2609 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2610 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2613 #ifdef USE_TCP_WRAPPERS
2615 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2616 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2617 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2618 expand_string_message);
2620 if (!hosts_ctl(tcp_wrappers_name,
2621 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2622 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2623 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2625 if (errno == 0 || errno == ENOENT)
2627 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2628 log_write(L_connection_reject,
2629 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2630 "(tcp wrappers)", host_and_ident(FALSE));
2631 smtp_printf("554 SMTP service not available\r\n");
2635 int save_errno = errno;
2636 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2637 "errno value %d\n", save_errno);
2638 log_write(L_connection_reject,
2639 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2640 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2641 smtp_printf("451 Temporary local problem - please try later\r\n");
2647 /* Check for reserved slots. The value of smtp_accept_count has already been
2648 incremented to include this process. */
2650 if (smtp_accept_max > 0 &&
2651 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2653 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2655 log_write(L_connection_reject,
2656 LOG_MAIN, "temporarily refused connection from %s: not in "
2657 "reserve list: connected=%d max=%d reserve=%d%s",
2658 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2659 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2660 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2661 "please try again later\r\n", smtp_active_hostname);
2664 reserved_host = TRUE;
2667 /* If a load level above which only messages from reserved hosts are
2668 accepted is set, check the load. For incoming calls via the daemon, the
2669 check is done in the superior process if there are no reserved hosts, to
2670 save a fork. In all cases, the load average will already be available
2671 in a global variable at this point. */
2673 if (smtp_load_reserve >= 0 &&
2674 load_average > smtp_load_reserve &&
2676 verify_check_host(&smtp_reserve_hosts) != OK)
2678 log_write(L_connection_reject,
2679 LOG_MAIN, "temporarily refused connection from %s: not in "
2680 "reserve list and load average = %.2f", host_and_ident(FALSE),
2681 (double)load_average/1000.0);
2682 smtp_printf("421 %s: Too much load; please try again later\r\n",
2683 smtp_active_hostname);
2687 /* Determine whether unqualified senders or recipients are permitted
2688 for this host. Unfortunately, we have to do this every time, in order to
2689 set the flags so that they can be inspected when considering qualifying
2690 addresses in the headers. For a site that permits no qualification, this
2691 won't take long, however. */
2693 allow_unqualified_sender =
2694 verify_check_host(&sender_unqualified_hosts) == OK;
2696 allow_unqualified_recipient =
2697 verify_check_host(&recipient_unqualified_hosts) == OK;
2699 /* Determine whether HELO/EHLO is required for this host. The requirement
2700 can be hard or soft. */
2702 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2704 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2706 /* Determine whether this hosts is permitted to send syntactic junk
2707 after a HELO or EHLO command. */
2709 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2712 /* For batch SMTP input we are now done. */
2714 if (smtp_batched_input) return TRUE;
2716 /* If valid Proxy Protocol source is connecting, set up session.
2717 * Failure will not allow any SMTP function other than QUIT. */
2719 #ifdef SUPPORT_PROXY
2720 proxy_session = FALSE;
2721 proxy_session_failed = FALSE;
2722 if (check_proxy_protocol_host())
2723 setup_proxy_protocol_host();
2726 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2727 smtps port for use with older style SSL MTAs. */
2730 if (tls_in.on_connect && tls_server_start(tls_require_ciphers, &user_msg) != OK)
2731 return smtp_log_tls_fail(user_msg);
2734 /* Run the connect ACL if it exists */
2737 if (acl_smtp_connect)
2740 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2743 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2748 /* Output the initial message for a two-way SMTP connection. It may contain
2749 newlines, which then cause a multi-line response to be given. */
2751 code = US"220"; /* Default status code */
2752 esc = US""; /* Default extended status code */
2753 esclen = 0; /* Length of esc */
2757 if (!(s = expand_string(smtp_banner)))
2758 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2759 "failed: %s", smtp_banner, expand_string_message);
2765 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2769 esclen = codelen - 4;
2773 /* Remove any terminating newlines; might as well remove trailing space too */
2776 while (p > s && isspace(p[-1])) p--;
2779 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2780 is all contained in a single IP packet. The original code wrote out the
2781 greeting using several calls to fprint/fputc, and on busy servers this could
2782 cause it to be split over more than one packet - which caused CC:Mail to fall
2783 over when it got the second part of the greeting after sending its first
2784 command. Sigh. To try to avoid this, build the complete greeting message
2785 first, and output it in one fell swoop. This gives a better chance of it
2786 ending up as a single packet. */
2788 ss = store_get(size);
2792 do /* At least once, in case we have an empty string */
2795 uschar *linebreak = Ustrchr(p, '\n');
2796 ss = string_catn(ss, &size, &ptr, code, 3);
2797 if (linebreak == NULL)
2800 ss = string_catn(ss, &size, &ptr, US" ", 1);
2804 len = linebreak - p;
2805 ss = string_catn(ss, &size, &ptr, US"-", 1);
2807 ss = string_catn(ss, &size, &ptr, esc, esclen);
2808 ss = string_catn(ss, &size, &ptr, p, len);
2809 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2811 if (linebreak != NULL) p++;
2815 ss[ptr] = 0; /* string_cat leaves room for this */
2817 /* Before we write the banner, check that there is no input pending, unless
2818 this synchronisation check is disabled. */
2822 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2823 "synchronization error (input sent without waiting for greeting): "
2824 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2825 string_printing(smtp_inptr));
2826 smtp_printf("554 SMTP synchronization error\r\n");
2830 /* Now output the banner */
2832 smtp_printf("%s", ss);
2840 /*************************************************
2841 * Handle SMTP syntax and protocol errors *
2842 *************************************************/
2844 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2845 to do so. Then transmit the error response. The return value depends on the
2846 number of syntax and protocol errors in this SMTP session.
2849 type error type, given as a log flag bit
2850 code response code; <= 0 means don't send a response
2851 data data to reflect in the response (can be NULL)
2852 errmess the error message
2854 Returns: -1 limit of syntax/protocol errors NOT exceeded
2855 +1 limit of syntax/protocol errors IS exceeded
2857 These values fit in with the values of the "done" variable in the main
2858 processing loop in smtp_setup_msg(). */
2861 synprot_error(int type, int code, uschar *data, uschar *errmess)
2865 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2866 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2867 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2869 if (++synprot_error_count > smtp_max_synprot_errors)
2872 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2873 "syntax or protocol errors (last command was \"%s\")",
2874 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2879 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2880 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2882 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2891 /*************************************************
2892 * Send SMTP response, possibly multiline *
2893 *************************************************/
2895 /* There are, it seems, broken clients out there that cannot handle multiline
2896 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2897 output nothing for non-final calls, and only the first line for anything else.
2900 code SMTP code, may involve extended status codes
2901 codelen length of smtp code; if > 4 there's an ESC
2902 final FALSE if the last line isn't the final line
2903 msg message text, possibly containing newlines
2909 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2914 if (!final && no_multiline_responses) return;
2919 esclen = codelen - 4;
2922 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2923 have had the same. Note: this code is also present in smtp_printf(). It would
2924 be tidier to have it only in one place, but when it was added, it was easier to
2925 do it that way, so as not to have to mess with the code for the RCPT command,
2926 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2928 if (rcpt_in_progress)
2930 if (rcpt_smtp_response == NULL)
2931 rcpt_smtp_response = string_copy(msg);
2932 else if (rcpt_smtp_response_same &&
2933 Ustrcmp(rcpt_smtp_response, msg) != 0)
2934 rcpt_smtp_response_same = FALSE;
2935 rcpt_in_progress = FALSE;
2938 /* Not output the message, splitting it up into multiple lines if necessary. */
2942 uschar *nl = Ustrchr(msg, '\n');
2945 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2948 else if (nl[1] == 0 || no_multiline_responses)
2950 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2951 (int)(nl - msg), msg);
2956 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2958 while (isspace(*msg)) msg++;
2966 /*************************************************
2967 * Parse user SMTP message *
2968 *************************************************/
2970 /* This function allows for user messages overriding the response code details
2971 by providing a suitable response code string at the start of the message
2972 user_msg. Check the message for starting with a response code and optionally an
2973 extended status code. If found, check that the first digit is valid, and if so,
2974 change the code pointer and length to use the replacement. An invalid code
2975 causes a panic log; in this case, if the log messages is the same as the user
2976 message, we must also adjust the value of the log message to show the code that
2977 is actually going to be used (the original one).
2979 This function is global because it is called from receive.c as well as within
2982 Note that the code length returned includes the terminating whitespace
2983 character, which is always included in the regex match.
2986 code SMTP code, may involve extended status codes
2987 codelen length of smtp code; if > 4 there's an ESC
2989 log_msg optional log message, to be adjusted with the new SMTP code
2990 check_valid if true, verify the response code
2996 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3002 if (!msg || !*msg) return;
3004 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3005 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3007 if (check_valid && (*msg)[0] != (*code)[0])
3009 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3010 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3011 if (log_msg != NULL && *log_msg == *msg)
3012 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3017 *codelen = ovector[1]; /* Includes final space */
3019 *msg += ovector[1]; /* Chop the code off the message */
3026 /*************************************************
3027 * Handle an ACL failure *
3028 *************************************************/
3030 /* This function is called when acl_check() fails. As well as calls from within
3031 this module, it is called from receive.c for an ACL after DATA. It sorts out
3032 logging the incident, and sets up the error response. A message containing
3033 newlines is turned into a multiline SMTP response, but for logging, only the
3036 There's a table of default permanent failure response codes to use in
3037 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3038 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3039 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3040 state, because there are broken clients that try VRFY before RCPT. A 5xx
3041 response should be given only when the address is positively known to be
3042 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3043 no explicit code, but if there is one we let it know best.
3044 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3046 From Exim 4.63, it is possible to override the response code details by
3047 providing a suitable response code string at the start of the message provided
3048 in user_msg. The code's first digit is checked for validity.
3051 where where the ACL was called from
3053 user_msg a message that can be included in an SMTP response
3054 log_msg a message for logging
3056 Returns: 0 in most cases
3057 2 if the failure code was FAIL_DROP, in which case the
3058 SMTP connection should be dropped (this value fits with the
3059 "done" variable in smtp_setup_msg() below)
3063 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3065 BOOL drop = rc == FAIL_DROP;
3069 uschar *sender_info = US"";
3071 #ifdef WITH_CONTENT_SCAN
3072 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3074 where == ACL_WHERE_PREDATA ? US"DATA" :
3075 where == ACL_WHERE_DATA ? US"after DATA" :
3076 #ifndef DISABLE_PRDR
3077 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3080 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3081 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3083 if (drop) rc = FAIL;
3085 /* Set the default SMTP code, and allow a user message to change it. */
3087 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3088 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3089 where != ACL_WHERE_VRFY);
3091 /* We used to have sender_address here; however, there was a bug that was not
3092 updating sender_address after a rewrite during a verify. When this bug was
3093 fixed, sender_address at this point became the rewritten address. I'm not sure
3094 this is what should be logged, so I've changed to logging the unrewritten
3095 address to retain backward compatibility. */
3097 #ifndef WITH_CONTENT_SCAN
3098 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3100 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3103 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3104 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3105 sender_host_authenticated ? US" A=" : US"",
3106 sender_host_authenticated ? sender_host_authenticated : US"",
3107 sender_host_authenticated && authenticated_id ? US":" : US"",
3108 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3112 /* If there's been a sender verification failure with a specific message, and
3113 we have not sent a response about it yet, do so now, as a preliminary line for
3114 failures, but not defers. However, always log it for defer, and log it for fail
3115 unless the sender_verify_fail log selector has been turned off. */
3117 if (sender_verified_failed &&
3118 !testflag(sender_verified_failed, af_sverify_told))
3120 BOOL save_rcpt_in_progress = rcpt_in_progress;
3121 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3123 setflag(sender_verified_failed, af_sverify_told);
3125 if (rc != FAIL || LOGGING(sender_verify_fail))
3126 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3127 host_and_ident(TRUE),
3128 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3129 sender_verified_failed->address,
3130 (sender_verified_failed->message == NULL)? US"" :
3131 string_sprintf(": %s", sender_verified_failed->message));
3133 if (rc == FAIL && sender_verified_failed->user_message)
3134 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3135 testflag(sender_verified_failed, af_verify_pmfail)?
3136 "Postmaster verification failed while checking <%s>\n%s\n"
3137 "Several RFCs state that you are required to have a postmaster\n"
3138 "mailbox for each mail domain. This host does not accept mail\n"
3139 "from domains whose servers reject the postmaster address."
3141 testflag(sender_verified_failed, af_verify_nsfail)?
3142 "Callback setup failed while verifying <%s>\n%s\n"
3143 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3144 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3145 "RFC requirements, and stops you from receiving standard bounce\n"
3146 "messages. This host does not accept mail from domains whose servers\n"
3149 "Verification failed for <%s>\n%s",
3150 sender_verified_failed->address,
3151 sender_verified_failed->user_message));
3153 rcpt_in_progress = save_rcpt_in_progress;
3156 /* Sort out text for logging */
3158 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3159 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3161 /* Send permanent failure response to the command, but the code used isn't
3162 always a 5xx one - see comments at the start of this function. If the original
3163 rc was FAIL_DROP we drop the connection and yield 2. */
3166 smtp_respond(smtp_code, codelen, TRUE,
3167 user_msg ? user_msg : US"Administrative prohibition");
3169 /* Send temporary failure response to the command. Don't give any details,
3170 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3171 verb, and for a header verify when smtp_return_error_details is set.
3173 This conditional logic is all somewhat of a mess because of the odd
3174 interactions between temp_details and return_error_details. One day it should
3175 be re-implemented in a tidier fashion. */
3178 if (acl_temp_details && user_msg)
3180 if ( smtp_return_error_details
3181 && sender_verified_failed
3182 && sender_verified_failed->message
3184 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3186 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3189 smtp_respond(smtp_code, codelen, TRUE,
3190 US"Temporary local problem - please try later");
3192 /* Log the incident to the logs that are specified by log_reject_target
3193 (default main, reject). This can be empty to suppress logging of rejections. If
3194 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3195 is closing if required and return 2. */
3197 if (log_reject_target != 0)
3200 uschar * tls = s_tlslog(NULL, NULL, NULL);
3201 if (!tls) tls = US"";
3203 uschar * tls = US"";
3205 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3206 log_reject_target, "%s%s%s %s%srejected %s%s",
3207 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3208 host_and_ident(TRUE),
3211 rc == FAIL ? US"" : US"temporarily ",
3215 if (!drop) return 0;
3217 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3218 smtp_get_connection_info());
3220 /* Run the not-quit ACL, but without any custom messages. This should not be a
3221 problem, because we get here only if some other ACL has issued "drop", and
3222 in that case, *its* custom messages will have been used above. */
3224 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3231 /*************************************************
3232 * Handle SMTP exit when QUIT is not given *
3233 *************************************************/
3235 /* This function provides a logging/statistics hook for when an SMTP connection
3236 is dropped on the floor or the other end goes away. It's a global function
3237 because it's called from receive.c as well as this module. As well as running
3238 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3239 response, either with a custom message from the ACL, or using a default. There
3240 is one case, however, when no message is output - after "drop". In that case,
3241 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3242 passed to this function.
3244 In case things go wrong while processing this function, causing an error that
3245 may re-enter this function, there is a recursion check.
3248 reason What $smtp_notquit_reason will be set to in the ACL;
3249 if NULL, the ACL is not run
3250 code The error code to return as part of the response
3251 defaultrespond The default message if there's no user_msg
3257 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3260 uschar *user_msg = NULL;
3261 uschar *log_msg = NULL;
3263 /* Check for recursive acll */
3265 if (smtp_exit_function_called)
3267 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3271 smtp_exit_function_called = TRUE;
3273 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3275 if (acl_smtp_notquit && reason)
3277 smtp_notquit_reason = reason;
3278 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3279 &log_msg)) == ERROR)
3280 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3284 /* Write an SMTP response if we are expected to give one. As the default
3285 responses are all internal, they should always fit in the buffer, but code a
3286 warning, just in case. Note that string_vformat() still leaves a complete
3287 string, even if it is incomplete. */
3289 if (code && defaultrespond)
3292 smtp_respond(code, 3, TRUE, user_msg);
3297 va_start(ap, defaultrespond);
3298 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3299 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3300 smtp_printf("%s %s\r\n", code, buffer);
3310 /*************************************************
3311 * Verify HELO argument *
3312 *************************************************/
3314 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3315 matched. It is also called from ACL processing if verify = helo is used and
3316 verification was not previously tried (i.e. helo_try_verify_hosts was not
3317 matched). The result of its processing is to set helo_verified and
3318 helo_verify_failed. These variables should both be FALSE for this function to
3321 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3322 for IPv6 ::ffff: literals.
3325 Returns: TRUE if testing was completed;
3326 FALSE on a temporary failure
3330 smtp_verify_helo(void)
3334 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3337 if (sender_helo_name == NULL)
3339 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3342 /* Deal with the case of -bs without an IP address */
3344 else if (sender_host_address == NULL)
3346 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3347 helo_verified = TRUE;
3350 /* Deal with the more common case when there is a sending IP address */
3352 else if (sender_helo_name[0] == '[')
3354 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3355 Ustrlen(sender_host_address)) == 0;
3360 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3361 helo_verified = Ustrncmp(sender_helo_name + 1,
3362 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3367 { if (helo_verified) debug_printf("matched host address\n"); }
3370 /* Do a reverse lookup if one hasn't already given a positive or negative
3371 response. If that fails, or the name doesn't match, try checking with a forward
3376 if (sender_host_name == NULL && !host_lookup_failed)
3377 yield = host_name_lookup() != DEFER;
3379 /* If a host name is known, check it and all its aliases. */
3381 if (sender_host_name)
3382 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3384 sender_helo_dnssec = sender_host_dnssec;
3385 HDEBUG(D_receive) debug_printf("matched host name\n");
3389 uschar **aliases = sender_host_aliases;
3391 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3393 sender_helo_dnssec = sender_host_dnssec;
3397 HDEBUG(D_receive) if (helo_verified)
3398 debug_printf("matched alias %s\n", *(--aliases));
3401 /* Final attempt: try a forward lookup of the helo name */
3410 h.name = sender_helo_name;
3417 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3419 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3420 NULL, NULL, NULL, &d, NULL, NULL);
3421 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3422 for (hh = &h; hh; hh = hh->next)
3423 if (Ustrcmp(hh->address, sender_host_address) == 0)
3425 helo_verified = TRUE;
3426 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3429 debug_printf("IP address for %s matches calling address\n"
3430 "Forward DNS security status: %sverified\n",
3431 sender_helo_name, sender_helo_dnssec ? "" : "un");
3438 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3445 /*************************************************
3446 * Send user response message *
3447 *************************************************/
3449 /* This function is passed a default response code and a user message. It calls
3450 smtp_message_code() to check and possibly modify the response code, and then
3451 calls smtp_respond() to transmit the response. I put this into a function
3452 just to avoid a lot of repetition.
3455 code the response code
3456 user_msg the user message
3462 smtp_user_msg(uschar *code, uschar *user_msg)
3465 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3466 smtp_respond(code, len, TRUE, user_msg);
3472 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3474 const uschar *set_id = NULL;
3477 /* Run the checking code, passing the remainder of the command line as
3478 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3479 it as the only set numerical variable. The authenticator may set $auth<n>
3480 and also set other numeric variables. The $auth<n> variables are preferred
3481 nowadays; the numerical variables remain for backwards compatibility.
3483 Afterwards, have a go at expanding the set_id string, even if
3484 authentication failed - for bad passwords it can be useful to log the
3485 userid. On success, require set_id to expand and exist, and put it in
3486 authenticated_id. Save this in permanent store, as the working store gets
3487 reset at HELO, RSET, etc. */
3489 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3491 expand_nlength[0] = 0; /* $0 contains nothing */
3493 rc = (au->info->servercode)(au, smtp_cmd_data);
3494 if (au->set_id) set_id = expand_string(au->set_id);
3495 expand_nmax = -1; /* Reset numeric variables */
3496 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3498 /* The value of authenticated_id is stored in the spool file and printed in
3499 log lines. It must not contain binary zeros or newline characters. In
3500 normal use, it never will, but when playing around or testing, this error
3501 can (did) happen. To guard against this, ensure that the id contains only
3502 printing characters. */
3504 if (set_id) set_id = string_printing(set_id);
3506 /* For the non-OK cases, set up additional logging data if set_id
3510 set_id = set_id && *set_id
3511 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3513 /* Switch on the result */
3518 if (!au->set_id || set_id) /* Complete success */
3520 if (set_id) authenticated_id = string_copy_malloc(set_id);
3521 sender_host_authenticated = au->name;
3522 authentication_failed = FALSE;
3523 authenticated_fail_id = NULL; /* Impossible to already be set? */
3526 (sender_host_address ? protocols : protocols_local)
3527 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3528 *s = *ss = US"235 Authentication succeeded";
3529 authenticated_by = au;
3533 /* Authentication succeeded, but we failed to expand the set_id string.
3534 Treat this as a temporary error. */
3536 auth_defer_msg = expand_string_message;
3540 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3541 *s = string_sprintf("435 Unable to authenticate at present%s",
3542 auth_defer_user_msg);
3543 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3544 set_id, auth_defer_msg);
3548 *s = *ss = US"501 Invalid base64 data";
3552 *s = *ss = US"501 Authentication cancelled";
3556 *s = *ss = US"553 Initial data not expected";
3560 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3561 *s = US"535 Incorrect authentication data";
3562 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3566 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3567 *s = US"435 Internal error";
3568 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3569 "check", set_id, rc);
3581 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3584 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3586 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3588 rd = Ustrlen(recipient) + 1;
3589 *recipient = rewrite_address_qualify(*recipient, TRUE);
3592 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3594 log_write(L_smtp_syntax_error,
3595 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3596 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3604 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3607 incomplete_transaction_log(US"QUIT");
3610 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3612 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3616 smtp_respond(US"221", 3, TRUE, *user_msgp);
3618 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3621 tls_close(TRUE, TRUE);
3624 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3625 smtp_get_connection_info());
3630 smtp_rset_handler(void)
3633 incomplete_transaction_log(US"RSET");
3634 smtp_printf("250 Reset OK\r\n");
3635 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3640 /*************************************************
3641 * Initialize for SMTP incoming message *
3642 *************************************************/
3644 /* This function conducts the initial dialogue at the start of an incoming SMTP
3645 message, and builds a list of recipients. However, if the incoming message
3646 is part of a batch (-bS option) a separate function is called since it would
3647 be messy having tests splattered about all over this function. This function
3648 therefore handles the case where interaction is occurring. The input and output
3649 files are set up in smtp_in and smtp_out.
3651 The global recipients_list is set to point to a vector of recipient_item
3652 blocks, whose number is given by recipients_count. This is extended by the
3653 receive_add_recipient() function. The global variable sender_address is set to
3654 the sender's address. The yield is +1 if a message has been successfully
3655 started, 0 if a QUIT command was encountered or the connection was refused from
3656 the particular host, or -1 if the connection was lost.
3660 Returns: > 0 message successfully started (reached DATA)
3661 = 0 QUIT read or end of file reached or call refused
3666 smtp_setup_msg(void)
3669 BOOL toomany = FALSE;
3670 BOOL discarded = FALSE;
3671 BOOL last_was_rej_mail = FALSE;
3672 BOOL last_was_rcpt = FALSE;
3673 void *reset_point = store_get(0);
3675 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3677 /* Reset for start of new message. We allow one RSET not to be counted as a
3678 nonmail command, for those MTAs that insist on sending it between every
3679 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3680 TLS between messages (an Exim client may do this if it has messages queued up
3681 for the host). Note: we do NOT reset AUTH at this point. */
3683 smtp_reset(reset_point);
3684 message_ended = END_NOTSTARTED;
3686 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3688 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3689 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3690 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3692 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3693 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3696 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3698 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3700 /* Batched SMTP is handled in a different function. */
3702 if (smtp_batched_input) return smtp_setup_batch_msg();
3704 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3705 value. The values are 2 larger than the required yield of the function. */
3709 const uschar **argv;
3710 uschar *etrn_command;
3711 uschar *etrn_serialize_key;
3713 uschar *log_msg, *smtp_code;
3714 uschar *user_msg = NULL;
3715 uschar *recipient = NULL;
3716 uschar *hello = NULL;
3718 BOOL was_rej_mail = FALSE;
3719 BOOL was_rcpt = FALSE;
3720 void (*oldsignal)(int);
3722 int start, end, sender_domain, recipient_domain;
3726 uschar *orcpt = NULL;
3730 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3731 if ( tls_in.active >= 0
3733 && tls_in.certificate_verified
3734 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3737 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3739 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3740 &user_msg, &log_msg)) != OK
3743 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3747 for (au = auths; au; au = au->next)
3748 if (strcmpic(US"tls", au->driver_name) == 0)
3750 smtp_cmd_data = NULL;
3752 if (smtp_in_auth(au, &s, &ss) == OK)
3753 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3755 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3762 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3763 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3764 US &off, sizeof(off));
3767 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3769 /* The AUTH command is not permitted to occur inside a transaction, and may
3770 occur successfully only once per connection. Actually, that isn't quite
3771 true. When TLS is started, all previous information about a connection must
3772 be discarded, so a new AUTH is permitted at that time.
3774 AUTH may only be used when it has been advertised. However, it seems that
3775 there are clients that send AUTH when it hasn't been advertised, some of
3776 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3777 So there's a get-out that allows this to happen.
3779 AUTH is initially labelled as a "nonmail command" so that one occurrence
3780 doesn't get counted. We change the label here so that multiple failing
3781 AUTHS will eventually hit the nonmail threshold. */
3785 authentication_failed = TRUE;
3786 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3788 if (!auth_advertised && !allow_auth_unadvertised)
3790 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3791 US"AUTH command used when not advertised");
3794 if (sender_host_authenticated)
3796 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3797 US"already authenticated");
3802 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3803 US"not permitted in mail transaction");
3810 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3811 &user_msg, &log_msg)) != OK
3814 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3818 /* Find the name of the requested authentication mechanism. */
3821 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3823 if (!isalnum(c) && c != '-' && c != '_')
3825 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3826 US"invalid character in authentication mechanism name");
3832 /* If not at the end of the line, we must be at white space. Terminate the
3833 name and move the pointer on to any data that may be present. */
3835 if (*smtp_cmd_data != 0)
3837 *smtp_cmd_data++ = 0;
3838 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3841 /* Search for an authentication mechanism which is configured for use
3842 as a server and which has been advertised (unless, sigh, allow_auth_
3843 unadvertised is set). */
3845 for (au = auths; au; au = au->next)
3846 if (strcmpic(s, au->public_name) == 0 && au->server &&
3847 (au->advertised || allow_auth_unadvertised))
3852 c = smtp_in_auth(au, &s, &ss);
3854 smtp_printf("%s\r\n", s);
3856 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3857 au->name, host_and_ident(FALSE), ss);
3860 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3861 string_sprintf("%s authentication mechanism not supported", s));
3863 break; /* AUTH_CMD */
3865 /* The HELO/EHLO commands are permitted to appear in the middle of a
3866 session as well as at the beginning. They have the effect of a reset in
3867 addition to their other functions. Their absence at the start cannot be
3868 taken to be an error.
3872 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3873 or 502 failure replies MUST be returned as appropriate. The SMTP
3874 server MUST stay in the same state after transmitting these replies
3875 that it was in before the EHLO was received.
3877 Therefore, we do not do the reset until after checking the command for
3878 acceptability. This change was made for Exim release 4.11. Previously
3879 it did the reset first. */
3892 HELO_EHLO: /* Common code for HELO and EHLO */
3893 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3894 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3896 /* Reject the HELO if its argument was invalid or non-existent. A
3897 successful check causes the argument to be saved in malloc store. */
3899 if (!check_helo(smtp_cmd_data))
3901 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3903 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3904 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3905 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3906 string_printing(smtp_cmd_argument));
3908 if (++synprot_error_count > smtp_max_synprot_errors)
3910 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3911 "syntax or protocol errors (last command was \"%s\")",
3912 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3919 /* If sender_host_unknown is true, we have got here via the -bs interface,
3920 not called from inetd. Otherwise, we are running an IP connection and the
3921 host address will be set. If the helo name is the primary name of this
3922 host and we haven't done a reverse lookup, force one now. If helo_required
3923 is set, ensure that the HELO name matches the actual host. If helo_verify
3924 is set, do the same check, but softly. */
3926 if (!sender_host_unknown)
3928 BOOL old_helo_verified = helo_verified;
3929 uschar *p = smtp_cmd_data;
3931 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3934 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3935 because otherwise the log can be confusing. */
3937 if (sender_host_name == NULL &&
3938 (deliver_domain = sender_helo_name, /* set $domain */
3939 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3940 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3941 (void)host_name_lookup();
3943 /* Rebuild the fullhost info to include the HELO name (and the real name
3944 if it was looked up.) */
3946 host_build_sender_fullhost(); /* Rebuild */
3947 set_process_info("handling%s incoming connection from %s",
3948 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3950 /* Verify if configured. This doesn't give much security, but it does
3951 make some people happy to be able to do it. If helo_required is set,
3952 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3953 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3954 now obsolescent, since the verification can now be requested selectively
3957 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
3958 if (helo_required || helo_verify)
3960 BOOL tempfail = !smtp_verify_helo();
3965 smtp_printf("%d %s argument does not match calling host\r\n",
3966 tempfail? 451 : 550, hello);
3967 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3968 tempfail? "temporarily " : "",
3969 hello, sender_helo_name, host_and_ident(FALSE));
3970 helo_verified = old_helo_verified;
3971 break; /* End of HELO/EHLO processing */
3973 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3974 "helo_try_verify_hosts\n", hello);
3979 #ifdef EXPERIMENTAL_SPF
3980 /* set up SPF context */
3981 spf_init(sender_helo_name, sender_host_address);
3984 /* Apply an ACL check if one is defined; afterwards, recheck
3985 synchronization in case the client started sending in a delay. */
3988 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3989 &user_msg, &log_msg)) != OK)
3991 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3992 sender_helo_name = NULL;
3993 host_build_sender_fullhost(); /* Rebuild */
3996 else if (!check_sync()) goto SYNC_FAILURE;
3998 /* Generate an OK reply. The default string includes the ident if present,
3999 and also the IP address if present. Reflecting back the ident is intended
4000 as a deterrent to mail forgers. For maximum efficiency, and also because
4001 some broken systems expect each response to be in a single packet, arrange
4002 that the entire reply is sent in one write(). */
4004 auth_advertised = FALSE;
4005 pipelining_advertised = FALSE;
4007 tls_advertised = FALSE;
4009 dsn_advertised = FALSE;
4011 smtputf8_advertised = FALSE;
4014 smtp_code = US"250 "; /* Default response code plus space*/
4015 if (user_msg == NULL)
4017 s = string_sprintf("%.3s %s Hello %s%s%s",
4019 smtp_active_hostname,
4020 (sender_ident == NULL)? US"" : sender_ident,
4021 (sender_ident == NULL)? US"" : US" at ",
4022 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
4027 if (sender_host_address != NULL)
4029 s = string_catn(s, &size, &ptr, US" [", 2);
4030 s = string_cat (s, &size, &ptr, sender_host_address);
4031 s = string_catn(s, &size, &ptr, US"]", 1);
4035 /* A user-supplied EHLO greeting may not contain more than one line. Note
4036 that the code returned by smtp_message_code() includes the terminating
4037 whitespace character. */
4043 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4044 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4045 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4047 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4048 "newlines: message truncated: %s", string_printing(s));
4055 s = string_catn(s, &size, &ptr, US"\r\n", 2);
4057 /* If we received EHLO, we must create a multiline response which includes
4058 the functions supported. */
4064 /* I'm not entirely happy with this, as an MTA is supposed to check
4065 that it has enough room to accept a message of maximum size before
4066 it sends this. However, there seems little point in not sending it.
4067 The actual size check happens later at MAIL FROM time. By postponing it
4068 till then, VRFY and EXPN can be used after EHLO when space is short. */
4070 if (thismessage_size_limit > 0)
4072 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
4073 thismessage_size_limit);
4074 s = string_cat(s, &size, &ptr, big_buffer);
4078 s = string_catn(s, &size, &ptr, smtp_code, 3);
4079 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
4082 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4083 clean; if it has an 8-bit character in its hand, it just sends it. It
4084 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4085 However, some users want this option simply in order to stop MUAs
4086 mangling messages that contain top-bit-set characters. It is therefore
4087 provided as an option. */
4089 if (accept_8bitmime)
4091 s = string_catn(s, &size, &ptr, smtp_code, 3);
4092 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
4095 /* Advertise DSN support if configured to do so. */
4096 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4098 s = string_catn(s, &size, &ptr, smtp_code, 3);
4099 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
4100 dsn_advertised = TRUE;
4103 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4104 permitted to issue them; a check is made when any host actually tries. */
4108 s = string_catn(s, &size, &ptr, smtp_code, 3);
4109 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
4113 s = string_catn(s, &size, &ptr, smtp_code, 3);
4114 s = string_catn(s, &size, &ptr, US"-VRFY\r\n", 7);
4118 s = string_catn(s, &size, &ptr, smtp_code, 3);
4119 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
4122 /* Exim is quite happy with pipelining, so let the other end know that
4123 it is safe to use it, unless advertising is disabled. */
4125 if (pipelining_enable &&
4126 verify_check_host(&pipelining_advertise_hosts) == OK)
4128 s = string_catn(s, &size, &ptr, smtp_code, 3);
4129 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
4130 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4131 pipelining_advertised = TRUE;
4135 /* If any server authentication mechanisms are configured, advertise
4136 them if the current host is in auth_advertise_hosts. The problem with
4137 advertising always is that some clients then require users to
4138 authenticate (and aren't configurable otherwise) even though it may not
4139 be necessary (e.g. if the host is in host_accept_relay).
4141 RFC 2222 states that SASL mechanism names contain only upper case
4142 letters, so output the names in upper case, though we actually recognize
4143 them in either case in the AUTH command. */
4147 && !sender_host_authenticated
4149 && verify_check_host(&auth_advertise_hosts) == OK
4154 for (au = auths; au; au = au->next)
4155 if (au->server && (au->advertise_condition == NULL ||
4156 expand_check_condition(au->advertise_condition, au->name,
4157 US"authenticator")))
4162 s = string_catn(s, &size, &ptr, smtp_code, 3);
4163 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
4165 auth_advertised = TRUE;
4168 s = string_catn(s, &size, &ptr, US" ", 1);
4169 s = string_cat (s, &size, &ptr, au->public_name);
4170 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
4171 au->advertised = TRUE;
4174 au->advertised = FALSE;
4176 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
4179 /* RFC 3030 CHUNKING */
4181 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4183 s = string_catn(s, &size, &ptr, smtp_code, 3);
4184 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
4185 chunking_offered = TRUE;
4186 chunking_state = CHUNKING_OFFERED;
4189 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4190 if it has been included in the binary, and the host matches
4191 tls_advertise_hosts. We must *not* advertise if we are already in a
4192 secure connection. */
4195 if (tls_in.active < 0 &&
4196 verify_check_host(&tls_advertise_hosts) != FAIL)
4198 s = string_catn(s, &size, &ptr, smtp_code, 3);
4199 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
4200 tls_advertised = TRUE;
4204 #ifndef DISABLE_PRDR
4205 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4208 s = string_catn(s, &size, &ptr, smtp_code, 3);
4209 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
4214 if ( accept_8bitmime
4215 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4217 s = string_catn(s, &size, &ptr, smtp_code, 3);
4218 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
4219 smtputf8_advertised = TRUE;
4223 /* Finish off the multiline reply with one that is always available. */
4225 s = string_catn(s, &size, &ptr, smtp_code, 3);
4226 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
4229 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4235 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
4239 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
4244 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
4245 memmove(cr, cr + 1, (ptr--) - (cr - s));
4246 debug_printf("SMTP>> %s", s);
4250 /* Reset the protocol and the state, abandoning any previous message. */
4252 (sender_host_address ? protocols : protocols_local)
4254 ? pextend + (sender_host_authenticated ? pauthed : 0)
4256 + (tls_in.active >= 0 ? pcrpted : 0)
4258 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4259 smtp_reset(reset_point);
4261 break; /* HELO/EHLO */
4264 /* The MAIL command requires an address as an operand. All we do
4265 here is to parse it for syntactic correctness. The form "<>" is
4266 a special case which converts into an empty string. The start/end
4267 pointers in the original are not used further for this address, as
4268 it is the canonical extracted address which is all that is kept. */
4272 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4273 was_rej_mail = TRUE; /* Reset if accepted */
4274 env_mail_type_t * mail_args; /* Sanity check & validate args */
4276 if (helo_required && !helo_seen)
4278 smtp_printf("503 HELO or EHLO required\r\n");
4279 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4280 "HELO/EHLO given", host_and_ident(FALSE));
4284 if (sender_address != NULL)
4286 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4287 US"sender already given");
4291 if (smtp_cmd_data[0] == 0)
4293 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4294 US"MAIL must have an address operand");
4298 /* Check to see if the limit for messages per connection would be
4299 exceeded by accepting further messages. */
4301 if (smtp_accept_max_per_connection > 0 &&
4302 smtp_mailcmd_count > smtp_accept_max_per_connection)
4304 smtp_printf("421 too many messages in this connection\r\n");
4305 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4306 "messages in one connection", host_and_ident(TRUE));
4310 /* Reset for start of message - even if this is going to fail, we
4311 obviously need to throw away any previous data. */
4313 cancel_cutthrough_connection(TRUE, US"MAIL received");
4314 smtp_reset(reset_point);
4316 sender_data = recipient_data = NULL;
4318 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4322 uschar *name, *value, *end;
4323 unsigned long int size;
4324 BOOL arg_error = FALSE;
4326 if (!extract_option(&name, &value)) break;
4328 for (mail_args = env_mail_type_list;
4329 mail_args->value != ENV_MAIL_OPT_NULL;
4332 if (strcmpic(name, mail_args->name) == 0)
4334 if (mail_args->need_value && strcmpic(value, US"") == 0)
4337 switch(mail_args->value)
4339 /* Handle SIZE= by reading the value. We don't do the check till later,
4340 in order to be able to log the sender address on failure. */
4341 case ENV_MAIL_OPT_SIZE:
4342 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4344 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4346 message_size = (int)size;
4352 /* If this session was initiated with EHLO and accept_8bitmime is set,
4353 Exim will have indicated that it supports the BODY=8BITMIME option. In
4354 fact, it does not support this according to the RFCs, in that it does not
4355 take any special action for forwarding messages containing 8-bit
4356 characters. That is why accept_8bitmime is not the default setting, but
4357 some sites want the action that is provided. We recognize both "8BITMIME"
4358 and "7BIT" as body types, but take no action. */
4359 case ENV_MAIL_OPT_BODY:
4360 if (accept_8bitmime) {
4361 if (strcmpic(value, US"8BITMIME") == 0)
4363 else if (strcmpic(value, US"7BIT") == 0)
4368 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4369 US"invalid data for BODY");
4372 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4378 /* Handle the two DSN options, but only if configured to do so (which
4379 will have caused "DSN" to be given in the EHLO response). The code itself
4380 is included only if configured in at build time. */
4382 case ENV_MAIL_OPT_RET:
4385 /* Check if RET has already been set */
4388 synprot_error(L_smtp_syntax_error, 501, NULL,
4389 US"RET can be specified once only");
4392 dsn_ret = strcmpic(value, US"HDRS") == 0
4394 : strcmpic(value, US"FULL") == 0
4397 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4398 /* Check for invalid invalid value, and exit with error */
4401 synprot_error(L_smtp_syntax_error, 501, NULL,
4402 US"Value for RET is invalid");
4407 case ENV_MAIL_OPT_ENVID:
4410 /* Check if the dsn envid has been already set */
4411 if (dsn_envid != NULL)
4413 synprot_error(L_smtp_syntax_error, 501, NULL,
4414 US"ENVID can be specified once only");
4417 dsn_envid = string_copy(value);
4418 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4422 /* Handle the AUTH extension. If the value given is not "<>" and either
4423 the ACL says "yes" or there is no ACL but the sending host is
4424 authenticated, we set it up as the authenticated sender. However, if the
4425 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4426 the condition is met. The value of AUTH is an xtext, which means that +,
4427 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4429 case ENV_MAIL_OPT_AUTH:
4430 if (Ustrcmp(value, "<>") != 0)
4435 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4437 /* Put back terminator overrides for error message */
4440 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4441 US"invalid data for AUTH");
4444 if (acl_smtp_mailauth == NULL)
4446 ignore_msg = US"client not authenticated";
4447 rc = (sender_host_authenticated != NULL)? OK : FAIL;
4451 ignore_msg = US"rejected by ACL";
4452 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4453 &user_msg, &log_msg);
4459 if (authenticated_by == NULL ||
4460 authenticated_by->mail_auth_condition == NULL ||
4461 expand_check_condition(authenticated_by->mail_auth_condition,
4462 authenticated_by->name, US"authenticator"))
4463 break; /* Accept the AUTH */
4465 ignore_msg = US"server_mail_auth_condition failed";
4466 if (authenticated_id != NULL)
4467 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4468 ignore_msg, authenticated_id);
4473 authenticated_sender = NULL;
4474 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4475 value, host_and_ident(TRUE), ignore_msg);
4478 /* Should only get DEFER or ERROR here. Put back terminator
4479 overrides for error message */
4484 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4491 #ifndef DISABLE_PRDR
4492 case ENV_MAIL_OPT_PRDR:
4494 prdr_requested = TRUE;
4499 case ENV_MAIL_OPT_UTF8:
4500 if (smtputf8_advertised)
4502 int old_pool = store_pool;
4504 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4505 message_smtputf8 = allow_utf8_domains = TRUE;
4506 store_pool = POOL_PERM;
4507 received_protocol = string_sprintf("utf8%s", received_protocol);
4508 store_pool = old_pool;
4512 /* No valid option. Stick back the terminator characters and break
4513 the loop. Do the name-terminator second as extract_option sets
4514 value==name when it found no equal-sign.
4515 An error for a malformed address will occur. */
4516 case ENV_MAIL_OPT_NULL:
4524 /* Break out of for loop if switch() had bad argument or
4525 when start of the email address is reached */
4526 if (arg_error) break;
4529 /* If we have passed the threshold for rate limiting, apply the current
4530 delay, and update it for next time, provided this is a limited host. */
4532 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4533 verify_check_host(&smtp_ratelimit_hosts) == OK)
4535 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4536 smtp_delay_mail/1000.0);
4537 millisleep((int)smtp_delay_mail);
4538 smtp_delay_mail *= smtp_rlm_factor;
4539 if (smtp_delay_mail > (double)smtp_rlm_limit)
4540 smtp_delay_mail = (double)smtp_rlm_limit;
4543 /* Now extract the address, first applying any SMTP-time rewriting. The
4544 TRUE flag allows "<>" as a sender address. */
4546 raw_sender = rewrite_existflags & rewrite_smtp
4547 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4548 global_rewrite_rules)
4552 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4557 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4561 sender_address = raw_sender;
4563 /* If there is a configured size limit for mail, check that this message
4564 doesn't exceed it. The check is postponed to this point so that the sender
4567 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4569 smtp_printf("552 Message size exceeds maximum permitted\r\n");
4570 log_write(L_size_reject,
4571 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4572 "message too big: size%s=%d max=%d",
4574 host_and_ident(TRUE),
4575 (message_size == INT_MAX)? ">" : "",
4577 thismessage_size_limit);
4578 sender_address = NULL;
4582 /* Check there is enough space on the disk unless configured not to.
4583 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4584 plus the current message - i.e. we accept the message only if it won't
4585 reduce the space below the threshold. Add 5000 to the size to allow for
4586 overheads such as the Received: line and storing of recipients, etc.
4587 By putting the check here, even when SIZE is not given, it allow VRFY
4588 and EXPN etc. to be used when space is short. */
4590 if (!receive_check_fs(
4591 (smtp_check_spool_space && message_size >= 0)?
4592 message_size + 5000 : 0))
4594 smtp_printf("452 Space shortage, please try later\r\n");
4595 sender_address = NULL;
4599 /* If sender_address is unqualified, reject it, unless this is a locally
4600 generated message, or the sending host or net is permitted to send
4601 unqualified addresses - typically local machines behaving as MUAs -
4602 in which case just qualify the address. The flag is set above at the start
4603 of the SMTP connection. */
4605 if (sender_domain == 0 && sender_address[0] != 0)
4607 if (allow_unqualified_sender)
4609 sender_domain = Ustrlen(sender_address) + 1;
4610 sender_address = rewrite_address_qualify(sender_address, FALSE);
4611 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4616 smtp_printf("501 %s: sender address must contain a domain\r\n",
4618 log_write(L_smtp_syntax_error,
4619 LOG_MAIN|LOG_REJECT,
4620 "unqualified sender rejected: <%s> %s%s",
4622 host_and_ident(TRUE),
4624 sender_address = NULL;
4629 /* Apply an ACL check if one is defined, before responding. Afterwards,
4630 when pipelining is not advertised, do another sync check in case the ACL
4631 delayed and the client started sending in the meantime. */
4635 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4636 if (rc == OK && !pipelining_advertised && !check_sync())
4642 if (rc == OK || rc == DISCARD)
4645 smtp_printf("%s%s%s", US"250 OK",
4646 #ifndef DISABLE_PRDR
4647 prdr_requested ? US", PRDR Requested" : US"",
4654 #ifndef DISABLE_PRDR
4656 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4658 smtp_user_msg(US"250", user_msg);
4660 smtp_delay_rcpt = smtp_rlr_base;
4661 recipients_discarded = (rc == DISCARD);
4662 was_rej_mail = FALSE;
4666 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4667 sender_address = NULL;
4672 /* The RCPT command requires an address as an operand. There may be any
4673 number of RCPT commands, specifying multiple recipients. We build them all
4674 into a data structure. The start/end values given by parse_extract_address
4675 are not used, as we keep only the extracted address. */
4680 was_rcpt = rcpt_in_progress = TRUE;
4682 /* There must be a sender address; if the sender was rejected and
4683 pipelining was advertised, we assume the client was pipelining, and do not
4684 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4685 get the same treatment. */
4687 if (sender_address == NULL)
4689 if (pipelining_advertised && last_was_rej_mail)
4691 smtp_printf("503 sender not yet given\r\n");
4692 was_rej_mail = TRUE;
4696 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4697 US"sender not yet given");
4698 was_rcpt = FALSE; /* Not a valid RCPT */
4704 /* Check for an operand */
4706 if (smtp_cmd_data[0] == 0)
4708 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4709 US"RCPT must have an address operand");
4714 /* Set the DSN flags orcpt and dsn_flags from the session*/
4720 uschar *name, *value;
4722 if (!extract_option(&name, &value))
4725 if (dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4727 /* Check whether orcpt has been already set */
4730 synprot_error(L_smtp_syntax_error, 501, NULL,
4731 US"ORCPT can be specified once only");
4734 orcpt = string_copy(value);
4735 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4738 else if (dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4740 /* Check if the notify flags have been already set */
4743 synprot_error(L_smtp_syntax_error, 501, NULL,
4744 US"NOTIFY can be specified once only");
4747 if (strcmpic(value, US"NEVER") == 0)
4748 flags |= rf_notify_never;
4755 while (*pp != 0 && *pp != ',') pp++;
4756 if (*pp == ',') *pp++ = 0;
4757 if (strcmpic(p, US"SUCCESS") == 0)
4759 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4760 flags |= rf_notify_success;
4762 else if (strcmpic(p, US"FAILURE") == 0)
4764 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4765 flags |= rf_notify_failure;
4767 else if (strcmpic(p, US"DELAY") == 0)
4769 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4770 flags |= rf_notify_delay;
4774 /* Catch any strange values */
4775 synprot_error(L_smtp_syntax_error, 501, NULL,
4776 US"Invalid value for NOTIFY parameter");
4781 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", flags);
4785 /* Unknown option. Stick back the terminator characters and break
4786 the loop. An error for a malformed address will occur. */
4790 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4797 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4798 as a recipient address */
4800 recipient = rewrite_existflags & rewrite_smtp
4801 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4802 global_rewrite_rules)
4805 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4806 &recipient_domain, FALSE)))
4808 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4813 /* If the recipient address is unqualified, reject it, unless this is a
4814 locally generated message. However, unqualified addresses are permitted
4815 from a configured list of hosts and nets - typically when behaving as
4816 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4817 really. The flag is set at the start of the SMTP connection.
4819 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4820 assumed this meant "reserved local part", but the revision of RFC 821 and
4821 friends now makes it absolutely clear that it means *mailbox*. Consequently
4822 we must always qualify this address, regardless. */
4824 if (!recipient_domain)
4825 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4832 /* Check maximum allowed */
4834 if (rcpt_count > recipients_max && recipients_max > 0)
4836 if (recipients_max_reject)
4839 smtp_printf("552 too many recipients\r\n");
4841 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4842 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4847 smtp_printf("452 too many recipients\r\n");
4849 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4850 "temporarily rejected: sender=<%s> %s", sender_address,
4851 host_and_ident(TRUE));
4858 /* If we have passed the threshold for rate limiting, apply the current
4859 delay, and update it for next time, provided this is a limited host. */
4861 if (rcpt_count > smtp_rlr_threshold &&
4862 verify_check_host(&smtp_ratelimit_hosts) == OK)
4864 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4865 smtp_delay_rcpt/1000.0);
4866 millisleep((int)smtp_delay_rcpt);
4867 smtp_delay_rcpt *= smtp_rlr_factor;
4868 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4869 smtp_delay_rcpt = (double)smtp_rlr_limit;
4872 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4873 for them. Otherwise, check the access control list for this recipient. As
4874 there may be a delay in this, re-check for a synchronization error
4875 afterwards, unless pipelining was advertised. */
4877 if (recipients_discarded)
4880 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4882 && !pipelining_advertised && !check_sync())
4885 /* The ACL was happy */
4890 smtp_user_msg(US"250", user_msg);
4892 smtp_printf("250 Accepted\r\n");
4893 receive_add_recipient(recipient, -1);
4895 /* Set the dsn flags in the recipients_list */
4896 recipients_list[recipients_count-1].orcpt = orcpt;
4897 recipients_list[recipients_count-1].dsn_flags = flags;
4899 DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4900 recipients_list[recipients_count-1].orcpt,
4901 recipients_list[recipients_count-1].dsn_flags);
4904 /* The recipient was discarded */
4906 else if (rc == DISCARD)
4909 smtp_user_msg(US"250", user_msg);
4911 smtp_printf("250 Accepted\r\n");
4914 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
4915 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4916 sender_address_unrewritten? sender_address_unrewritten : sender_address,
4917 smtp_cmd_argument, recipients_discarded? "MAIL" : "RCPT",
4918 log_msg ? US": " : US"", log_msg ? log_msg : US"");
4921 /* Either the ACL failed the address, or it was deferred. */
4925 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
4926 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
4931 /* The DATA command is legal only if it follows successful MAIL FROM
4932 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
4933 not counted as a protocol error if it follows RCPT (which must have been
4934 rejected if there are no recipients.) This function is complete when a
4935 valid DATA command is encountered.
4937 Note concerning the code used: RFC 2821 says this:
4939 - If there was no MAIL, or no RCPT, command, or all such commands
4940 were rejected, the server MAY return a "command out of sequence"
4941 (503) or "no valid recipients" (554) reply in response to the
4944 The example in the pipelining RFC 2920 uses 554, but I use 503 here
4945 because it is the same whether pipelining is in use or not.
4947 If all the RCPT commands that precede DATA provoked the same error message
4948 (often indicating some kind of system error), it is helpful to include it
4949 with the DATA rejection (an idea suggested by Tony Finch). */
4956 if (chunking_state != CHUNKING_OFFERED)
4958 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4959 US"BDAT command used when CHUNKING not advertised");
4963 /* grab size, endmarker */
4965 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
4967 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4968 US"missing size for BDAT command");
4971 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
4972 ? CHUNKING_LAST : CHUNKING_ACTIVE;
4973 chunking_data_left = chunking_datasize;
4974 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
4975 (int)chunking_state, chunking_data_left);
4977 lwr_receive_getc = receive_getc;
4978 lwr_receive_ungetc = receive_ungetc;
4979 receive_getc = bdat_getc;
4980 receive_ungetc = bdat_ungetc;
4988 DATA_BDAT: /* Common code for DATA and BDAT */
4989 if (!discarded && recipients_count <= 0)
4991 if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
4993 uschar *code = US"503";
4994 int len = Ustrlen(rcpt_smtp_response);
4995 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
4997 /* Responses from smtp_printf() will have \r\n on the end */
4998 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
4999 rcpt_smtp_response[len-2] = 0;
5000 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5002 if (pipelining_advertised && last_was_rcpt)
5003 smtp_printf("503 Valid RCPT command must precede %s\r\n",
5004 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5006 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5007 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5008 ? US"valid RCPT command must precede DATA"
5009 : US"valid RCPT command must precede BDAT");
5011 if (chunking_state > CHUNKING_OFFERED)
5016 if (toomany && recipients_max_reject)
5018 sender_address = NULL; /* This will allow a new MAIL without RSET */
5019 sender_address_unrewritten = NULL;
5020 smtp_printf("554 Too many recipients\r\n");
5024 if (chunking_state > CHUNKING_OFFERED)
5025 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5028 /* If there is an ACL, re-check the synchronization afterwards, since the
5029 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5030 to get the DATA command sent. */
5032 if (acl_smtp_predata == NULL && cutthrough.fd < 0)
5036 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5037 enable_dollar_recipients = TRUE;
5038 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5040 enable_dollar_recipients = FALSE;
5041 if (rc == OK && !check_sync())
5045 { /* Either the ACL failed the address, or it was deferred. */
5046 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5052 smtp_user_msg(US"354", user_msg);
5055 "354 Enter message, ending with \".\" on a line by itself\r\n");
5059 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5060 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5061 US &on, sizeof(on));
5064 message_ended = END_NOTENDED; /* Indicate in middle of data */
5075 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5076 &start, &end, &recipient_domain, FALSE)))
5078 smtp_printf("501 %s\r\n", errmess);
5082 if (!recipient_domain)
5083 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5087 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5088 &user_msg, &log_msg)) != OK)
5089 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5093 address_item * addr = deliver_make_addr(address, FALSE);
5095 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5096 -1, -1, NULL, NULL, NULL))
5099 s = string_sprintf("250 <%s> is deliverable", address);
5103 s = (addr->user_message != NULL)?
5104 string_sprintf("451 <%s> %s", address, addr->user_message) :
5105 string_sprintf("451 Cannot resolve <%s> at this time", address);
5109 s = (addr->user_message != NULL)?
5110 string_sprintf("550 <%s> %s", address, addr->user_message) :
5111 string_sprintf("550 <%s> is not deliverable", address);
5112 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5113 smtp_cmd_argument, host_and_ident(TRUE));
5117 smtp_printf("%s\r\n", s);
5125 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5127 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5130 BOOL save_log_testing_mode = log_testing_mode;
5131 address_test_mode = log_testing_mode = TRUE;
5132 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5133 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5135 address_test_mode = FALSE;
5136 log_testing_mode = save_log_testing_mode; /* true for -bh */
5145 if (!tls_advertised)
5147 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5148 US"STARTTLS command used when not advertised");
5152 /* Apply an ACL check if one is defined */
5154 if ( acl_smtp_starttls
5155 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5156 &user_msg, &log_msg)) != OK
5159 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5163 /* RFC 2487 is not clear on when this command may be sent, though it
5164 does state that all information previously obtained from the client
5165 must be discarded if a TLS session is started. It seems reasonable to
5166 do an implied RSET when STARTTLS is received. */
5168 incomplete_transaction_log(US"STARTTLS");
5169 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5170 smtp_reset(reset_point);
5172 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5174 /* There's an attack where more data is read in past the STARTTLS command
5175 before TLS is negotiated, then assumed to be part of the secure session
5176 when used afterwards; we use segregated input buffers, so are not
5177 vulnerable, but we want to note when it happens and, for sheer paranoia,
5178 ensure that the buffer is "wiped".
5179 Pipelining sync checks will normally have protected us too, unless disabled
5180 by configuration. */
5182 if (receive_smtp_buffered())
5185 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5186 if (tls_in.active < 0)
5187 smtp_inend = smtp_inptr = smtp_inbuffer;
5188 /* and if TLS is already active, tls_server_start() should fail */
5191 /* There is nothing we value in the input buffer and if TLS is successfully
5192 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5193 fresh content into it. The buffer contains arbitrary content from an
5194 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5195 It seems safest to just wipe away the content rather than leave it as a
5196 target to jump to. */
5198 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5200 /* Attempt to start up a TLS session, and if successful, discard all
5201 knowledge that was obtained previously. At least, that's what the RFC says,
5202 and that's what happens by default. However, in order to work round YAEB,
5203 there is an option to remember the esmtp state. Sigh.
5205 We must allow for an extra EHLO command and an extra AUTH command after
5206 STARTTLS that don't add to the nonmail command count. */
5209 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5211 if (!tls_remember_esmtp)
5212 helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
5213 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5214 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5215 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5216 if (sender_helo_name != NULL)
5218 store_free(sender_helo_name);
5219 sender_helo_name = NULL;
5220 host_build_sender_fullhost(); /* Rebuild */
5221 set_process_info("handling incoming TLS connection from %s",
5222 host_and_ident(FALSE));
5225 (sender_host_address ? protocols : protocols_local)
5227 ? pextend + (sender_host_authenticated ? pauthed : 0)
5229 + (tls_in.active >= 0 ? pcrpted : 0)
5232 sender_host_authenticated = NULL;
5233 authenticated_id = NULL;
5234 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5235 DEBUG(D_tls) debug_printf("TLS active\n");
5236 break; /* Successful STARTTLS */
5239 (void) smtp_log_tls_fail(s);
5241 /* Some local configuration problem was discovered before actually trying
5242 to do a TLS handshake; give a temporary error. */
5246 smtp_printf("454 TLS currently unavailable\r\n");
5250 /* Hard failure. Reject everything except QUIT or closed connection. One
5251 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5252 set, but we must still reject all incoming commands. */
5254 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5255 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5258 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5259 smtp_get_connection_info());
5260 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5264 /* It is perhaps arguable as to which exit ACL should be called here,
5265 but as it is probably a situation that almost never arises, it
5266 probably doesn't matter. We choose to call the real QUIT ACL, which in
5267 some sense is perhaps "right". */
5272 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5273 &log_msg)) == ERROR))
5274 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5277 smtp_respond(US"221", 3, TRUE, user_msg);
5279 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
5280 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5281 smtp_get_connection_info());
5286 smtp_printf("554 Security failure\r\n");
5289 tls_close(TRUE, TRUE);
5294 /* The ACL for QUIT is provided for gathering statistical information or
5295 similar; it does not affect the response code, but it can supply a custom
5299 smtp_quit_handler(&user_msg, &log_msg);
5305 smtp_rset_handler();
5306 cancel_cutthrough_connection(TRUE, US"RSET received");
5307 smtp_reset(reset_point);
5314 smtp_printf("250 OK\r\n");
5318 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5319 used, a check will be done for permitted hosts. Show STARTTLS only if not
5320 already in a TLS session and if it would be advertised in the EHLO
5325 smtp_printf("214-Commands supported:\r\n");
5329 Ustrcat(buffer, " AUTH");
5331 if (tls_in.active < 0 &&
5332 verify_check_host(&tls_advertise_hosts) != FAIL)
5333 Ustrcat(buffer, " STARTTLS");
5335 Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT");
5336 Ustrcat(buffer, " NOOP QUIT RSET HELP");
5337 if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN");
5338 if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN");
5339 if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY");
5340 smtp_printf("214%s\r\n", buffer);
5346 incomplete_transaction_log(US"connection lost");
5347 smtp_notquit_exit(US"connection-lost", US"421",
5348 US"%s lost input connection", smtp_active_hostname);
5350 /* Don't log by default unless in the middle of a message, as some mailers
5351 just drop the call rather than sending QUIT, and it clutters up the logs.
5354 if (sender_address != NULL || recipients_count > 0)
5355 log_write(L_lost_incoming_connection,
5357 "unexpected %s while reading SMTP command from %s%s",
5358 sender_host_unknown? "EOF" : "disconnection",
5359 host_and_ident(FALSE), smtp_read_error);
5361 else log_write(L_smtp_connection, LOG_MAIN, "%s lost%s",
5362 smtp_get_connection_info(), smtp_read_error);
5370 if (sender_address != NULL)
5372 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5373 US"ETRN is not permitted inside a transaction");
5377 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5378 host_and_ident(FALSE));
5380 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5381 &user_msg, &log_msg)) != OK)
5383 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5387 /* Compute the serialization key for this command. */
5389 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5391 /* If a command has been specified for running as a result of ETRN, we
5392 permit any argument to ETRN. If not, only the # standard form is permitted,
5393 since that is strictly the only kind of ETRN that can be implemented
5394 according to the RFC. */
5396 if (smtp_etrn_command != NULL)
5400 etrn_command = smtp_etrn_command;
5401 deliver_domain = smtp_cmd_data;
5402 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5403 US"ETRN processing", &error);
5404 deliver_domain = NULL;
5407 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5409 smtp_printf("458 Internal failure\r\n");
5414 /* Else set up to call Exim with the -R option. */
5418 if (*smtp_cmd_data++ != '#')
5420 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5421 US"argument must begin with #");
5424 etrn_command = US"exim -R";
5425 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5426 *queue_name ? 4 : 2,
5427 US"-R", smtp_cmd_data,
5428 US"-MCG", queue_name);
5431 /* If we are host-testing, don't actually do anything. */
5437 debug_printf("ETRN command is: %s\n", etrn_command);
5438 debug_printf("ETRN command execution skipped\n");
5440 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5441 else smtp_user_msg(US"250", user_msg);
5446 /* If ETRN queue runs are to be serialized, check the database to
5447 ensure one isn't already running. */
5449 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5451 smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
5455 /* Fork a child process and run the command. We don't want to have to
5456 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5457 forking. It should be set that way anyway for external incoming SMTP,
5458 but we save and restore to be tidy. If serialization is required, we
5459 actually run the command in yet another process, so we can wait for it
5460 to complete and then remove the serialization lock. */
5462 oldsignal = signal(SIGCHLD, SIG_IGN);
5464 if ((pid = fork()) == 0)
5466 smtp_input = FALSE; /* This process is not associated with the */
5467 (void)fclose(smtp_in); /* SMTP call any more. */
5468 (void)fclose(smtp_out);
5470 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5472 /* If not serializing, do the exec right away. Otherwise, fork down
5473 into another process. */
5475 if (!smtp_etrn_serialize || (pid = fork()) == 0)
5477 DEBUG(D_exec) debug_print_argv(argv);
5478 exim_nullstd(); /* Ensure std{in,out,err} exist */
5479 execv(CS argv[0], (char *const *)argv);
5480 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5481 etrn_command, strerror(errno));
5482 _exit(EXIT_FAILURE); /* paranoia */
5485 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5486 is, we are in the first subprocess, after forking again. All we can do
5487 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5488 complete, before removing the serialization. */
5491 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5492 "failed: %s", strerror(errno));
5496 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5498 (void)wait(&status);
5499 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5503 enq_end(etrn_serialize_key);
5504 _exit(EXIT_SUCCESS);
5507 /* Back in the top level SMTP process. Check that we started a subprocess
5508 and restore the signal state. */
5512 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5514 smtp_printf("458 Unable to fork process\r\n");
5515 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5519 if (user_msg == NULL) smtp_printf("250 OK\r\n");
5520 else smtp_user_msg(US"250", user_msg);
5523 signal(SIGCHLD, oldsignal);
5528 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5529 US"unexpected argument data");
5533 /* This currently happens only for NULLs, but could be extended. */
5536 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5537 US"NULL character(s) present (shown as '?')");
5538 smtp_printf("501 NULL characters are not allowed in SMTP commands\r\n");
5544 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5545 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5546 c = smtp_inend - smtp_inptr;
5547 if (c > 150) c = 150;
5549 incomplete_transaction_log(US"sync failure");
5550 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5551 "(next input sent too soon: pipelining was%s advertised): "
5552 "rejected \"%s\" %s next input=\"%s\"",
5553 pipelining_advertised? "" : " not",
5554 smtp_cmd_buffer, host_and_ident(TRUE),
5555 string_printing(smtp_inptr));
5556 smtp_notquit_exit(US"synchronization-error", US"554",
5557 US"SMTP synchronization error");
5558 done = 1; /* Pretend eof - drops connection */
5562 case TOO_MANY_NONMAIL_CMD:
5563 s = smtp_cmd_buffer;
5564 while (*s != 0 && !isspace(*s)) s++;
5565 incomplete_transaction_log(US"too many non-mail commands");
5566 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5567 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5568 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5569 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5570 done = 1; /* Pretend eof - drops connection */
5573 #ifdef SUPPORT_PROXY
5574 case PROXY_FAIL_IGNORE_CMD:
5575 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
5580 if (unknown_command_count++ >= smtp_max_unknown_commands)
5582 log_write(L_smtp_syntax_error, LOG_MAIN,
5583 "SMTP syntax error in \"%s\" %s %s",
5584 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5585 US"unrecognized command");
5586 incomplete_transaction_log(US"unrecognized command");
5587 smtp_notquit_exit(US"bad-commands", US"500",
5588 US"Too many unrecognized commands");
5590 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5591 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5592 string_printing(smtp_cmd_buffer));
5595 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5596 US"unrecognized command");
5600 /* This label is used by goto's inside loops that want to break out to
5601 the end of the command-processing loop. */
5604 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5605 last_was_rcpt = was_rcpt; /* protocol error handling */
5609 return done - 2; /* Convert yield values */
5614 /* End of smtp_in.c */