1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) The Exim Maintainers 2020 - 2024 */
6 /* Copyright (c) University of Cambridge 1995 - 2018 */
7 /* See the file NOTICE for conditions of use and distribution. */
8 /* SPDX-License-Identifier: GPL-2.0-or-later */
10 /* Functions for handling an incoming SMTP call. */
17 /* Initialize for TCP wrappers if so configured. It appears that the macro
18 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
19 including that header, and restore its value afterwards. */
21 #ifdef USE_TCP_WRAPPERS
24 #define EXIM_HAVE_IPV6
30 #define HAVE_IPV6 TRUE
33 int allow_severity = LOG_INFO;
34 int deny_severity = LOG_NOTICE;
35 uschar *tcp_wrappers_name;
39 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
40 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
41 commands that accept arguments, and this in particular applies to AUTH, where
42 the data can be quite long. More recently this value was 2048 in Exim;
43 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
44 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
45 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
46 we need room to handle large base64-encoded AUTHs for GSSAPI.
49 #define SMTP_CMD_BUFFER_SIZE 16384
51 /* Size of buffer for reading SMTP incoming packets */
53 #define IN_BUFFER_SIZE 8192
55 /* Structure for SMTP command list */
62 short int is_mail_cmd;
65 /* Codes for identifying commands. We order them so that those that come first
66 are those for which synchronization is always required. Checking this can help
70 /* These commands are required to be synchronized, i.e. to be the last in a
71 block of commands when pipelining. */
73 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
74 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
75 ETRN_CMD, /* This by analogy with TURN from the RFC */
76 STARTTLS_CMD, /* Required by the STARTTLS RFC */
77 TLS_AUTH_CMD, /* auto-command at start of SSL */
78 #ifdef EXPERIMENTAL_XCLIENT
79 XCLIENT_CMD, /* per xlexkiro implementation */
82 /* This is a dummy to identify the non-sync commands when pipelining */
84 NON_SYNC_CMD_PIPELINING,
86 /* These commands need not be synchronized when pipelining */
88 MAIL_CMD, RCPT_CMD, RSET_CMD,
89 #ifndef DISABLE_WELLKNOWN
93 /* This is a dummy to identify the non-sync commands when not pipelining */
95 NON_SYNC_CMD_NON_PIPELINING,
97 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
98 processed the message is sent using a series of BDAT commands"
99 implies that BDAT should be synchronized. However, we see Google, at least,
100 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
101 processing of the RCPT response(s). We shall do the same, and not require
102 synch for BDAT. Worse, as the chunk may (very likely will) follow the
103 command-header in the same packet we cannot do the usual "is there any
104 follow-on data after the command line" even for non-pipeline mode.
105 So we'll need an explicit check after reading the expected chunk amount
106 when non-pipe, before sending the ACK. */
110 /* I have been unable to find a statement about the use of pipelining
111 with AUTH, so to be on the safe side it is here, though I kind of feel
112 it should be up there with the synchronized commands. */
116 /* I'm not sure about these, but I don't think they matter. */
121 PROXY_FAIL_IGNORE_CMD,
124 /* These are specials that don't correspond to actual commands */
126 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
131 /* This is a convenience macro for adding the identity of an SMTP command
132 to the circular buffer that holds a list of the last n received. */
135 smtp_connection_had[smtp_ch_index++] = n; \
136 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
139 /*************************************************
140 * Local static variables *
141 *************************************************/
144 BOOL auth_advertised :1;
146 BOOL tls_advertised :1;
148 BOOL dsn_advertised :1;
150 BOOL helo_verify_required :1;
153 BOOL helo_accept_junk :1;
154 #ifndef DISABLE_PIPE_CONNECT
155 BOOL pipe_connect_acceptable :1;
157 BOOL rcpt_smtp_response_same :1;
158 BOOL rcpt_in_progress :1;
159 BOOL smtp_exit_function_called :1;
161 BOOL smtputf8_advertised :1;
164 .helo_verify_required = FALSE,
165 .helo_verify = FALSE,
166 .smtp_exit_function_called = FALSE,
169 static auth_instance *authenticated_by;
170 static int count_nonmail;
171 static int nonmail_command_count;
172 static int synprot_error_count;
173 static int unknown_command_count;
174 static int sync_cmd_limit;
175 static int smtp_write_error = 0;
177 static uschar *rcpt_smtp_response;
178 static uschar *smtp_data_buffer;
179 static uschar *smtp_cmd_data;
181 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
182 final fields of all except AUTH are forced TRUE at the start of a new message
183 setup, to allow one of each between messages that is not counted as a nonmail
184 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
185 allow a new EHLO after starting up TLS.
187 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
188 counted. However, the flag is changed when AUTH is received, so that multiple
189 failing AUTHs will eventually hit the limit. After a successful AUTH, another
190 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
191 forced TRUE, to allow for the re-authentication that can happen at that point.
193 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
194 count of non-mail commands and possibly provoke an error.
196 tls_auth is a pseudo-command, never expected in input. It is activated
197 on TLS startup and looks for a tls authenticator. */
208 #ifdef EXPERIMENTAL_XCLIENT
213 static smtp_cmd_list cmd_list[] = {
214 /* name len cmd has_arg is_mail_cmd */
216 [CL_RSET] = { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
217 [CL_HELO] = { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
218 [CL_EHLO] = { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
219 [CL_AUTH] = { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
221 [CL_STLS] = { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
222 [CL_TLAU] = { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
224 #ifdef EXPERIMENTAL_XCLIENT
225 [CL_XCLI] = { "xclient", sizeof("xclient")-1, XCLIENT_CMD, TRUE, FALSE },
228 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
229 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
230 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
231 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
232 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
233 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
234 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
235 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
236 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
237 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE },
238 #ifndef DISABLE_WELLKNOWN
239 { "wellknown", sizeof("wellknown")-1, WELLKNOWN_CMD, TRUE, FALSE },
243 /* This list of names is used for performing the smtp_no_mail logging action. */
245 uschar * smtp_names[] =
247 [SCH_NONE] = US"NONE",
248 [SCH_AUTH] = US"AUTH",
249 [SCH_DATA] = US"DATA",
250 [SCH_BDAT] = US"BDAT",
251 [SCH_EHLO] = US"EHLO",
252 [SCH_ETRN] = US"ETRN",
253 [SCH_EXPN] = US"EXPN",
254 [SCH_HELO] = US"HELO",
255 [SCH_HELP] = US"HELP",
256 [SCH_MAIL] = US"MAIL",
257 [SCH_NOOP] = US"NOOP",
258 [SCH_QUIT] = US"QUIT",
259 [SCH_RCPT] = US"RCPT",
260 [SCH_RSET] = US"RSET",
261 [SCH_STARTTLS] = US"STARTTLS",
262 [SCH_VRFY] = US"VRFY",
263 #ifndef DISABLE_WELLKNOWN
264 [SCH_WELLKNOWN] = US"WELLKNOWN",
266 #ifdef EXPERIMENTAL_XCLIENT
267 [SCH_XCLIENT] = US"XCLIENT",
271 static uschar *protocols_local[] = {
272 US"local-smtp", /* HELO */
273 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
274 US"local-esmtp", /* EHLO */
275 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
276 US"local-esmtpa", /* EHLO->AUTH */
277 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
279 static uschar *protocols[] = {
281 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
282 US"esmtp", /* EHLO */
283 US"esmtps", /* EHLO->STARTTLS->EHLO */
284 US"esmtpa", /* EHLO->AUTH */
285 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
290 #define pcrpted 1 /* added to pextend or pnormal */
291 #define pauthed 2 /* added to pextend */
293 /* Sanity check and validate optional args to MAIL FROM: envelope */
296 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
300 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
306 uschar * name; /* option requested during MAIL cmd */
307 int value; /* enum type */
308 BOOL need_value; /* TRUE requires value (name=value pair format)
309 FALSE is a singleton */
311 static env_mail_type_t env_mail_type_list[] = {
312 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
313 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
314 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
316 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
318 { US"RET", ENV_MAIL_OPT_RET, TRUE },
319 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
321 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
323 /* keep this the last entry */
324 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
327 /* When reading SMTP from a remote host, we have to use our own versions of the
328 C input-reading functions, in order to be able to flush the SMTP output only
329 when about to read more data from the socket. This is the only way to get
330 optimal performance when the client is using pipelining. Flushing for every
331 command causes a separate packet and reply packet each time; saving all the
332 responses up (when pipelining) combines them into one packet and one response.
334 For simplicity, these functions are used for *all* SMTP input, not only when
335 receiving over a socket. However, after setting up a secure socket (SSL), input
336 is read via the OpenSSL library, and another set of functions is used instead
339 These functions are set in the receive_getc etc. variables and called with the
340 same interface as the C functions. However, since there can only ever be
341 one incoming SMTP call, we just use a single buffer and flags. There is no need
342 to implement a complicated private FILE-like structure.*/
344 static uschar *smtp_inbuffer;
345 static uschar *smtp_inptr;
346 static uschar *smtp_inend;
347 static int smtp_had_eof;
348 static int smtp_had_error;
351 /* forward declarations */
352 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
353 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
354 static void smtp_quit_handler(uschar **, uschar **);
355 static void smtp_rset_handler(void);
357 /*************************************************
358 * Log incomplete transactions *
359 *************************************************/
361 /* This function is called after a transaction has been aborted by RSET, QUIT,
362 connection drops or other errors. It logs the envelope information received
363 so far in order to preserve address verification attempts.
365 Argument: string to indicate what aborted the transaction
370 incomplete_transaction_log(uschar * what)
372 if (!sender_address /* No transaction in progress */
373 || !LOGGING(smtp_incomplete_transaction))
376 /* Build list of recipients for logging */
378 if (recipients_count > 0)
380 raw_recipients = store_get(recipients_count * sizeof(uschar *), GET_UNTAINTED);
381 for (int i = 0; i < recipients_count; i++)
382 raw_recipients[i] = recipients_list[i].address;
383 raw_recipients_count = recipients_count;
386 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
387 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
393 log_close_event(const uschar * reason)
395 log_write(L_smtp_connection, LOG_MAIN, "%s D=%s closed %s",
396 smtp_get_connection_info(), string_timesince(&smtp_connection_start), reason);
401 smtp_command_timeout_exit(void)
403 log_write(L_lost_incoming_connection,
404 LOG_MAIN, "SMTP command timeout on%s connection from %s D=%s",
405 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE),
406 string_timesince(&smtp_connection_start));
407 if (smtp_batched_input)
408 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
409 smtp_notquit_exit(US"command-timeout", US"421",
410 US"%s: SMTP command timeout - closing connection",
411 smtp_active_hostname);
412 exim_exit(EXIT_FAILURE);
416 smtp_command_sigterm_exit(void)
418 log_close_event(US"after SIGTERM");
419 if (smtp_batched_input)
420 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
421 smtp_notquit_exit(US"signal-exit", US"421",
422 US"%s: Service not available - closing connection", smtp_active_hostname);
423 exim_exit(EXIT_FAILURE);
427 smtp_data_timeout_exit(void)
429 log_write(L_lost_incoming_connection, LOG_MAIN,
430 "SMTP data timeout (message abandoned) on connection from %s F=<%s> D=%s",
431 sender_fullhost ? sender_fullhost : US"local process", sender_address,
432 string_timesince(&smtp_connection_start));
433 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
434 /* Does not return */
438 smtp_data_sigint_exit(void)
440 log_close_event(had_data_sigint == SIGTERM ? US"SIGTERM":US"SIGINT");
441 receive_bomb_out(US"signal-exit",
442 US"Service not available - SIGTERM or SIGINT received");
443 /* Does not return */
447 /******************************************************************************/
448 /* SMTP input buffer handling. Most of these are similar to stdio routines. */
453 /* Set up the buffer for inputting using direct read() calls, and arrange to
454 call the local functions instead of the standard C ones. Place a NUL at the
455 end of the buffer to safety-stop C-string reads from it. */
457 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
458 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
459 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
461 smtp_inptr = smtp_inend = smtp_inbuffer;
462 smtp_had_eof = smtp_had_error = 0;
467 /* Refill the buffer, and notify DKIM verification code.
468 Return false for error or EOF.
472 smtp_refill(unsigned lim)
476 if (!smtp_out) return FALSE;
478 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
480 /* Limit amount read, so non-message data is not fed to DKIM.
481 Take care to not touch the safety NUL at the end of the buffer. */
483 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
485 if (smtp_receive_timeout > 0) ALARM_CLR(0);
488 /* Must put the error text in fixed store, because this might be during
489 header reading, where it releases unused store above the header. */
492 if (had_command_timeout) /* set by signal handler */
493 smtp_command_timeout_exit(); /* does not return */
494 if (had_command_sigterm)
495 smtp_command_sigterm_exit();
496 if (had_data_timeout)
497 smtp_data_timeout_exit();
499 smtp_data_sigint_exit();
501 smtp_had_error = save_errno;
502 smtp_read_error = string_copy_perm(
503 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
510 dkim_exim_verify_feed(smtp_inbuffer, rc);
512 smtp_inend = smtp_inbuffer + rc;
513 smtp_inptr = smtp_inbuffer;
518 /* Check if there is buffered data */
523 return smtp_inptr < smtp_inend;
526 /* SMTP version of getc()
528 This gets the next byte from the SMTP input buffer. If the buffer is empty,
529 it flushes the output, and refills the buffer, with a timeout. The signal
530 handler is set appropriately by the calling function. This function is not used
531 after a connection has negotiated itself into an TLS/SSL state.
533 Arguments: lim Maximum amount to read/buffer
534 Returns: the next character or EOF
538 smtp_getc(unsigned lim)
540 if (!smtp_hasc() && !smtp_refill(lim)) return EOF;
541 return *smtp_inptr++;
544 /* Get many bytes, refilling buffer if needed */
547 smtp_getbuf(unsigned * len)
552 if (!smtp_hasc() && !smtp_refill(*len))
553 { *len = 0; return NULL; }
555 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
562 /* Copy buffered data to the dkim feed.
563 Called, unless TLS, just before starting to read message headers. */
566 smtp_get_cache(unsigned lim)
569 int n = smtp_inend - smtp_inptr;
573 dkim_exim_verify_feed(smtp_inptr, n);
578 /* SMTP version of ungetc()
579 Puts a character back in the input buffer. Only ever called once.
584 Returns: the character
590 if (smtp_inptr <= smtp_inbuffer) /* NB: NOT smtp_hasc() ! */
591 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "buffer underflow in smtp_ungetc");
598 /* SMTP version of feof()
599 Tests for a previous EOF
602 Returns: non-zero if the eof flag is set
612 /* SMTP version of ferror()
613 Tests for a previous read error, and returns with errno
614 restored to what it was when the error was detected.
617 Returns: non-zero if the error flag is set
623 errno = smtp_had_error;
624 return smtp_had_error;
628 /* Check if a getc will block or not */
631 smtp_could_getc(void)
635 struct timeval tzero = {.tv_sec = 0, .tv_usec = 0};
637 if (smtp_inptr < smtp_inend)
640 fd = fileno(smtp_in);
643 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
645 if (rc <= 0) return FALSE; /* Not ready to read */
646 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
647 if (rc < 0) return FALSE; /* End of file or error */
654 /******************************************************************************/
655 /*************************************************
656 * Recheck synchronization *
657 *************************************************/
659 /* Synchronization checks can never be perfect because a packet may be on its
660 way but not arrived when the check is done. Normally, the checks happen when
661 commands are read: Exim ensures that there is no more input in the input buffer.
662 In normal cases, the response to the command will be fast, and there is no
665 However, for some commands an ACL is run, and that can include delays. In those
666 cases, it is useful to do another check on the input just before sending the
667 response. This also applies at the start of a connection. This function does
668 that check by means of the select() function, as long as the facility is not
669 disabled or inappropriate. A failure of select() is ignored.
671 When there is unwanted input, we read it so that it appears in the log of the
675 Returns: TRUE if all is well; FALSE if there is input pending
679 wouldblock_reading(void)
682 if (tls_in.active.sock >= 0)
683 return !tls_could_getc();
686 return !smtp_could_getc();
692 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
695 return wouldblock_reading();
699 /******************************************************************************/
700 /* Variants of the smtp_* input handling functions for use in CHUNKING mode */
702 /* Forward declarations */
703 static inline void bdat_push_receive_functions(void);
704 static inline void bdat_pop_receive_functions(void);
707 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
708 previous BDAT chunk and getting new ones when we run out. Uses the
709 underlying smtp_getc or tls_getc both for that and for getting the
710 (buffered) data byte. EOD signals (an expected) no further data.
711 ERR signals a protocol error, and EOF a closed input stream.
713 Called from read_bdat_smtp() in receive.c for the message body, but also
714 by the headers read loop in receive_msg(); manipulates chunking_state
715 to handle the BDAT command/response.
716 Placed here due to the correlation with the above smtp_getc(), which it wraps,
717 and also by the need to do smtp command/response handling.
719 Arguments: lim (ignored)
720 Returns: the next character or ERR, EOD or EOF
724 bdat_getc(unsigned lim)
726 uschar * user_msg = NULL;
735 if (chunking_data_left > 0)
736 return lwr_receive_getc(chunking_data_left--);
738 bdat_pop_receive_functions();
740 dkim_save = dkim_collect_input;
741 dkim_collect_input = 0;
744 /* Unless PIPELINING was offered, there should be no next command
745 until after we ack that chunk */
747 if (!f.smtp_in_pipelining_advertised && !check_sync())
749 unsigned n = smtp_inend - smtp_inptr;
752 incomplete_transaction_log(US"sync failure");
753 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
754 "(next input sent too soon: pipelining was not advertised): "
755 "rejected \"%s\" %s next input=\"%s\"%s",
756 smtp_cmd_buffer, host_and_ident(TRUE),
757 string_printing(string_copyn(smtp_inptr, n)),
758 smtp_inend - smtp_inptr > n ? "..." : "");
759 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
760 US"SMTP synchronization error");
761 goto repeat_until_rset;
764 /* If not the last, ack the received chunk. The last response is delayed
765 until after the data ACL decides on it */
767 if (chunking_state == CHUNKING_LAST)
770 dkim_collect_input = dkim_save;
771 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
772 dkim_collect_input = 0;
777 smtp_printf("250 %u byte chunk received\r\n", SP_NO_MORE, chunking_datasize);
778 chunking_state = CHUNKING_OFFERED;
779 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
781 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
782 QUIT, RSET or NOOP but handling them seems obvious */
785 switch(smtp_read_command(TRUE, 1))
788 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
789 US"only BDAT permissible after non-LAST BDAT");
792 switch(smtp_read_command(TRUE, 1))
794 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
795 case EOF_CMD: return EOF;
796 case RSET_CMD: smtp_rset_handler(); return ERR;
797 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
798 US"only RSET accepted now") > 0)
800 goto repeat_until_rset;
804 smtp_quit_handler(&user_msg, &log_msg);
815 smtp_printf("250 OK\r\n", SP_NO_MORE);
822 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
824 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
825 US"missing size for BDAT command");
828 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
829 ? CHUNKING_LAST : CHUNKING_ACTIVE;
830 chunking_data_left = chunking_datasize;
831 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
832 (int)chunking_state, chunking_data_left);
834 if (chunking_datasize == 0)
835 if (chunking_state == CHUNKING_LAST)
839 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
840 US"zero size for BDAT command");
841 goto repeat_until_rset;
844 bdat_push_receive_functions();
846 dkim_collect_input = dkim_save;
848 break; /* to top of main loop */
857 if (chunking_data_left > 0)
858 return lwr_receive_hasc();
863 bdat_getbuf(unsigned * len)
867 if (chunking_data_left <= 0)
868 { *len = 0; return NULL; }
870 if (*len > chunking_data_left) *len = chunking_data_left;
871 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
872 chunking_data_left -= *len;
877 bdat_flush_data(void)
879 while (chunking_data_left)
881 unsigned n = chunking_data_left;
882 if (!bdat_getbuf(&n)) break;
885 bdat_pop_receive_functions();
886 chunking_state = CHUNKING_OFFERED;
887 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
892 bdat_push_receive_functions(void)
894 /* push the current receive_* function on the "stack", and
895 replace them by bdat_getc(), which in turn will use the lwr_receive_*
896 functions to do the dirty work. */
897 if (!lwr_receive_getc)
899 lwr_receive_getc = receive_getc;
900 lwr_receive_getbuf = receive_getbuf;
901 lwr_receive_hasc = receive_hasc;
902 lwr_receive_ungetc = receive_ungetc;
906 DEBUG(D_receive) debug_printf("chunking double-push receive functions\n");
909 receive_getc = bdat_getc;
910 receive_getbuf = bdat_getbuf;
911 receive_hasc = bdat_hasc;
912 receive_ungetc = bdat_ungetc;
916 bdat_pop_receive_functions(void)
918 if (!lwr_receive_getc)
920 DEBUG(D_receive) debug_printf("chunking double-pop receive functions\n");
923 receive_getc = lwr_receive_getc;
924 receive_getbuf = lwr_receive_getbuf;
925 receive_hasc = lwr_receive_hasc;
926 receive_ungetc = lwr_receive_ungetc;
928 lwr_receive_getc = NULL;
929 lwr_receive_getbuf = NULL;
930 lwr_receive_hasc = NULL;
931 lwr_receive_ungetc = NULL;
937 chunking_data_left++;
938 bdat_push_receive_functions(); /* we're not done yet, calling push is safe, because it checks the state before pushing anything */
939 return lwr_receive_ungetc(ch);
944 /******************************************************************************/
946 /*************************************************
947 * Write formatted string to SMTP channel *
948 *************************************************/
950 /* This is a separate function so that we don't have to repeat everything for
951 TLS support or debugging. It is global so that the daemon and the
952 authentication functions can use it. It does not return any error indication,
953 because major problems such as dropped connections won't show up till an output
954 flush for non-TLS connections. The smtp_fflush() function is available for
955 checking that: for convenience, TLS output errors are remembered here so that
956 they are also picked up later by smtp_fflush().
958 This function is exposed to the local_scan API; do not change the signature.
962 more further data expected
963 ... optional arguments
969 smtp_printf(const char *format, BOOL more, ...)
974 smtp_vprintf(format, more, ap);
978 /* This is split off so that verify.c:respond_printf() can, in effect, call
979 smtp_printf(), bearing in mind that in C a vararg function can't directly
980 call another vararg function, only a function which accepts a va_list.
982 This function is exposed to the local_scan API; do not change the signature.
984 /*XXX consider passing caller-info in, for string_vformat-onward */
987 smtp_vprintf(const char *format, BOOL more, va_list ap)
989 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
992 /* Use taint-unchecked routines for writing into big_buffer, trusting
993 that we'll never expand it. */
995 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
996 string_from_gstring(&gs);
998 DEBUG(D_receive) for (const uschar * t, * s = gs.s;
999 s && (t = Ustrchr(s, '\r'));
1000 s = t + 2) /* \r\n */
1001 debug_printf("%s %.*s\n",
1002 s == gs.s ? "SMTP>>" : " ",
1007 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
1008 smtp_closedown(US"Unexpected error");
1009 exim_exit(EXIT_FAILURE);
1012 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
1013 have had the same. Note: this code is also present in smtp_respond(). It would
1014 be tidier to have it only in one place, but when it was added, it was easier to
1015 do it that way, so as not to have to mess with the code for the RCPT command,
1016 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
1018 if (fl.rcpt_in_progress)
1020 if (!rcpt_smtp_response)
1021 rcpt_smtp_response = string_copy(big_buffer);
1022 else if (fl.rcpt_smtp_response_same &&
1023 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
1024 fl.rcpt_smtp_response_same = FALSE;
1025 fl.rcpt_in_progress = FALSE;
1028 /* Now write the string */
1032 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
1034 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
1036 smtp_write_error = -1;
1041 /*************************************************
1042 * Flush SMTP out and check for error *
1043 *************************************************/
1045 /* This function isn't currently used within Exim (it detects errors when it
1046 tries to read the next SMTP input), but is available for use in local_scan().
1047 It flushes the output and checks for errors.
1050 Returns: 0 for no error; -1 after an error
1056 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
1060 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
1062 (fflush(smtp_out) != 0)
1064 smtp_write_error = -1;
1066 return smtp_write_error;
1071 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
1072 a reponse with the one following. */
1075 pipeline_response(void)
1077 if ( !smtp_enforce_sync || !sender_host_address
1078 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
1081 if (wouldblock_reading()) return FALSE;
1082 f.smtp_in_pipelining_used = TRUE;
1087 #ifndef DISABLE_PIPE_CONNECT
1089 pipeline_connect_sends(void)
1091 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
1094 if (wouldblock_reading()) return FALSE;
1095 f.smtp_in_early_pipe_used = TRUE;
1100 /*************************************************
1101 * SMTP command read timeout *
1102 *************************************************/
1104 /* Signal handler for timing out incoming SMTP commands. This attempts to
1107 Argument: signal number (SIGALRM)
1112 command_timeout_handler(int sig)
1114 had_command_timeout = sig;
1119 /*************************************************
1120 * SIGTERM received *
1121 *************************************************/
1123 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1125 Argument: signal number (SIGTERM)
1130 command_sigterm_handler(int sig)
1132 had_command_sigterm = sig;
1138 /*************************************************
1139 * Read one command line *
1140 *************************************************/
1142 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1143 There are sites that don't do this, and in any case internal SMTP probably
1144 should check only for LF. Consequently, we check here for LF only. The line
1145 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1146 an unknown command. The command is read into the global smtp_cmd_buffer so that
1147 it is available via $smtp_command.
1149 The character reading routine sets up a timeout for each block actually read
1150 from the input (which may contain more than one command). We set up a special
1151 signal handler that closes down the session on a timeout. Control does not
1152 return when it runs.
1155 check_sync if TRUE, check synchronization rules if global option is TRUE
1156 buffer_lim maximum to buffer in lower layer
1158 Returns: a code identifying the command (enumerated above)
1162 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1166 BOOL hadnull = FALSE;
1168 had_command_timeout = 0;
1169 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1171 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1173 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1175 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1183 smtp_cmd_buffer[ptr++] = c;
1186 receive_linecount++; /* For BSMTP errors */
1187 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1189 /* If hit end of file, return pseudo EOF command. Whether we have a
1190 part-line already read doesn't matter, since this is an error state. */
1192 if (c == EOF) return EOF_CMD;
1194 /* Remove any CR and white space at the end of the line, and terminate the
1197 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1198 smtp_cmd_buffer[ptr] = 0;
1200 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1202 /* NULLs are not allowed in SMTP commands */
1204 if (hadnull) return BADCHAR_CMD;
1206 /* Scan command list and return identity, having set the data pointer
1207 to the start of the actual data characters. Check for SMTP synchronization
1210 for (smtp_cmd_list * p = cmd_list; p < cmd_list + nelem(cmd_list); p++)
1212 #ifdef SUPPORT_PROXY
1213 /* Only allow QUIT command if Proxy Protocol parsing failed */
1214 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1218 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1219 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1220 || smtp_cmd_buffer[p->len] == 0
1221 || smtp_cmd_buffer[p->len] == ' '
1224 if ( smtp_inptr < smtp_inend /* Outstanding input */
1225 && p->cmd < sync_cmd_limit /* Command should sync */
1226 && check_sync /* Local flag set */
1227 && smtp_enforce_sync /* Global flag set */
1228 && sender_host_address != NULL /* Not local input */
1229 && !f.sender_host_notsocket /* Really is a socket */
1233 /* The variables $smtp_command and $smtp_command_argument point into the
1234 unmodified input buffer. A copy of the latter is taken for actual
1235 processing, so that it can be chopped up into separate parts if necessary,
1236 for example, when processing a MAIL command options such as SIZE that can
1237 follow the sender address. */
1239 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1240 Uskip_whitespace(&smtp_cmd_argument);
1241 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1242 smtp_cmd_data = smtp_data_buffer;
1244 /* Count non-mail commands from those hosts that are controlled in this
1245 way. The default is all hosts. We don't waste effort checking the list
1246 until we get a non-mail command, but then cache the result to save checking
1247 again. If there's a DEFER while checking the host, assume it's in the list.
1249 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1250 start of each incoming message by fiddling with the value in the table. */
1252 if (!p->is_mail_cmd)
1254 if (count_nonmail == TRUE_UNSET) count_nonmail =
1255 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1256 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1257 return TOO_MANY_NONMAIL_CMD;
1260 /* If there is data for a command that does not expect it, generate the
1263 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1267 #ifdef SUPPORT_PROXY
1268 /* Only allow QUIT command if Proxy Protocol parsing failed */
1269 if (proxy_session && f.proxy_session_failed)
1270 return PROXY_FAIL_IGNORE_CMD;
1273 /* Enforce synchronization for unknown commands */
1275 if ( smtp_inptr < smtp_inend /* Outstanding input */
1276 && check_sync /* Local flag set */
1277 && smtp_enforce_sync /* Global flag set */
1278 && sender_host_address /* Not local input */
1279 && !f.sender_host_notsocket /* Really is a socket */
1289 /*************************************************
1290 * Forced closedown of call *
1291 *************************************************/
1293 /* This function is called from log.c when Exim is dying because of a serious
1294 disaster, and also from some other places. If an incoming non-batched SMTP
1295 channel is open, it swallows the rest of the incoming message if in the DATA
1296 phase, sends the reply string, and gives an error to all subsequent commands
1297 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1301 message SMTP reply string to send, excluding the code
1307 smtp_closedown(uschar * message)
1309 if (!smtp_in || smtp_batched_input) return;
1310 receive_swallow_smtp();
1311 smtp_printf("421 %s\r\n", SP_NO_MORE, message);
1313 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1319 f.smtp_in_quit = TRUE;
1320 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
1325 smtp_printf("250 Reset OK\r\n", SP_NO_MORE);
1329 smtp_printf("421 %s\r\n", SP_NO_MORE, message);
1337 /*************************************************
1338 * Set up connection info for logging *
1339 *************************************************/
1341 /* This function is called when logging information about an SMTP connection.
1342 It sets up appropriate source information, depending on the type of connection.
1343 If sender_fullhost is NULL, we are at a very early stage of the connection;
1344 just use the IP address.
1347 Returns: a string describing the connection
1351 smtp_get_connection_info(void)
1353 const uschar * hostname = sender_fullhost
1354 ? sender_fullhost : sender_host_address;
1355 gstring * g = string_catn(NULL, US"SMTP connection", 15);
1357 if (LOGGING(connection_id))
1358 g = string_fmt_append(g, " Ci=%s", connection_id);
1359 g = string_catn(g, US" from ", 6);
1362 g = string_cat(g, hostname);
1364 else if (f.sender_host_unknown || f.sender_host_notsocket)
1365 g = string_cat(g, sender_ident ? sender_ident : US"NULL");
1367 else if (f.is_inetd)
1368 g = string_append(g, 2, hostname, US" (via inetd)");
1370 else if (LOGGING(incoming_interface) && interface_address)
1371 g = string_fmt_append(g, "%s I=[%s]:%d", hostname, interface_address, interface_port);
1374 g = string_cat(g, hostname);
1376 gstring_release_unused(g);
1377 return string_from_gstring(g);
1383 /* Append TLS-related information to a log line
1386 g String under construction: allocated string to extend, or NULL
1388 Returns: Allocated string or NULL
1391 s_tlslog(gstring * g)
1393 if (LOGGING(tls_cipher) && tls_in.cipher)
1395 g = string_append(g, 2, US" X=", tls_in.cipher);
1396 #ifndef DISABLE_TLS_RESUME
1397 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1398 g = string_catn(g, US"*", 1);
1401 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1402 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1403 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1404 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1405 if (LOGGING(tls_sni) && tls_in.sni)
1406 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1414 s_connhad_log(gstring * g)
1416 const uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1417 ? US" C=..." : US" C=";
1419 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1420 if (smtp_connection_had[i] != SCH_NONE)
1422 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1425 for (int i = 0; i < smtp_ch_index; i++, sep = US",")
1426 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1431 /*************************************************
1432 * Log lack of MAIL if so configured *
1433 *************************************************/
1435 /* This function is called when an SMTP session ends. If the log selector
1436 smtp_no_mail is set, write a log line giving some details of what has happened
1437 in the SMTP session.
1444 smtp_log_no_mail(void)
1449 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1452 if (sender_host_authenticated)
1454 g = string_append(g, 2, US" A=", sender_host_authenticated);
1455 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1462 g = s_connhad_log(g);
1464 if (!(s = string_from_gstring(g))) s = US"";
1466 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1467 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1468 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1472 /* Return list of recent smtp commands */
1477 gstring * list = NULL;
1480 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1481 if (smtp_connection_had[i] != SCH_NONE)
1482 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1484 for (int i = 0; i < smtp_ch_index; i++)
1485 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1487 s = string_from_gstring(list);
1488 return s ? s : US"";
1494 /*************************************************
1495 * Check HELO line and set sender_helo_name *
1496 *************************************************/
1498 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1499 the domain name of the sending host, or an ip literal in square brackets. The
1500 argument is placed in sender_helo_name, which is in malloc store, because it
1501 must persist over multiple incoming messages. If helo_accept_junk is set, this
1502 host is permitted to send any old junk (needed for some broken hosts).
1503 Otherwise, helo_allow_chars can be used for rogue characters in general
1504 (typically people want to let in underscores).
1507 s the data portion of the line (already past any white space)
1509 Returns: TRUE or FALSE
1513 check_helo(uschar *s)
1516 uschar *end = s + Ustrlen(s);
1517 BOOL yield = fl.helo_accept_junk;
1519 /* Discard any previous helo name */
1521 sender_helo_name = NULL;
1523 /* Skip tests if junk is permitted. */
1527 /* Allow the new standard form for IPv6 address literals, namely,
1528 [IPv6:....], and because someone is bound to use it, allow an equivalent
1529 IPv4 form. Allow plain addresses as well. */
1536 if (strncmpic(s, US"[IPv6:", 6) == 0)
1537 yield = (string_is_ip_address(s+6, NULL) == 6);
1538 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1539 yield = (string_is_ip_address(s+6, NULL) == 4);
1541 yield = (string_is_ip_address(s+1, NULL) != 0);
1546 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1547 that have been configured (usually underscore - sigh). */
1550 for (yield = TRUE; *s; s++)
1551 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1552 Ustrchr(helo_allow_chars, *s) == NULL)
1558 /* Save argument if OK */
1560 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
1568 /*************************************************
1569 * Extract SMTP command option *
1570 *************************************************/
1572 /* This function picks the next option setting off the end of smtp_cmd_data. It
1573 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1574 things that can appear there.
1577 name point this at the name
1578 value point this at the data string
1580 Returns: TRUE if found an option
1584 extract_option(uschar **name, uschar **value)
1588 if (Ustrlen(smtp_cmd_data) <= 0) return FALSE;
1589 v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1590 while (v > smtp_cmd_data && isspace(*v)) v--;
1593 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1595 /* Take care to not stop at a space embedded in a quoted local-part */
1598 do v--; while (v > smtp_cmd_data && *v != '"');
1599 if (v <= smtp_cmd_data) return FALSE;
1603 if (v <= smtp_cmd_data) return FALSE;
1608 while (n > smtp_cmd_data && isalpha(n[-1])) n--;
1609 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1610 if (n <= smtp_cmd_data || !isspace(n[-1])) return FALSE;
1627 /*************************************************
1628 * Reset for new message *
1629 *************************************************/
1631 /* This function is called whenever the SMTP session is reset from
1632 within either of the setup functions; also from the daemon loop.
1634 Argument: the stacking pool storage reset point
1639 smtp_reset(void *reset_point)
1641 recipients_list = NULL;
1642 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1643 raw_recipients_count = recipients_count = recipients_list_max = 0;
1644 message_linecount = 0;
1646 message_body = message_body_end = NULL;
1647 acl_added_headers = NULL;
1648 acl_removed_headers = NULL;
1649 f.queue_only_policy = FALSE;
1650 rcpt_smtp_response = NULL;
1651 fl.rcpt_smtp_response_same = TRUE;
1652 fl.rcpt_in_progress = FALSE;
1653 f.deliver_freeze = FALSE; /* Can be set by ACL */
1654 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1655 fake_response = OK; /* Can be set by ACL */
1656 #ifdef WITH_CONTENT_SCAN
1657 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
1659 f.submission_mode = FALSE; /* Can be set by ACL */
1660 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
1661 f.active_local_from_check = local_from_check; /* Can be set by ACL */
1662 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1663 sending_ip_address = NULL;
1664 return_path = sender_address = NULL;
1665 deliver_localpart_data = deliver_domain_data =
1666 recipient_data = sender_data = NULL; /* Can be set by ACL */
1667 recipient_verify_failure = NULL;
1668 deliver_localpart_parent = deliver_localpart_orig = NULL;
1669 deliver_domain_parent = deliver_domain_orig = NULL;
1670 callout_address = NULL;
1671 submission_name = NULL; /* Can be set by ACL */
1672 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1673 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1674 sender_verified_list = NULL; /* No senders verified */
1675 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1676 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1678 authenticated_sender = NULL;
1679 #ifdef EXPERIMENTAL_BRIGHTMAIL
1681 bmi_verdicts = NULL;
1683 dnslist_domain = dnslist_matched = NULL;
1684 #ifndef DISABLE_DKIM
1685 dkim_cur_signer = dkim_signers =
1686 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
1687 f.dkim_disable_verify = FALSE;
1688 dkim_collect_input = 0;
1689 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
1690 dkim_key_length = 0;
1692 #ifdef SUPPORT_DMARC
1693 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
1695 #ifdef EXPERIMENTAL_ARC
1696 arc_state = arc_state_reason = NULL;
1697 arc_received_instance = 0;
1701 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
1702 #ifndef DISABLE_PRDR
1703 prdr_requested = FALSE;
1706 message_smtputf8 = FALSE;
1708 #ifdef WITH_CONTENT_SCAN
1711 body_linecount = body_zerocount = 0;
1713 lookup_value = NULL; /* Can be set by ACL */
1714 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1715 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1716 /* Note that ratelimiters_conn persists across resets. */
1718 /* Reset message ACL variables */
1722 /* Warning log messages are saved in malloc store. They are saved to avoid
1723 repetition in the same message, but it seems right to repeat them for different
1726 while (acl_warn_logged)
1728 string_item *this = acl_warn_logged;
1729 acl_warn_logged = acl_warn_logged->next;
1733 misc_mod_smtp_reset();
1735 store_reset(reset_point);
1738 return store_mark();
1745 /*************************************************
1746 * Initialize for incoming batched SMTP message *
1747 *************************************************/
1749 /* This function is called from smtp_setup_msg() in the case when
1750 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1751 of messages in one file with SMTP commands between them. All errors must be
1752 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1753 relevant. After an error on a sender, or an invalid recipient, the remainder
1754 of the message is skipped. The value of received_protocol is already set.
1757 Returns: > 0 message successfully started (reached DATA)
1758 = 0 QUIT read or end of file reached
1759 < 0 should not occur
1763 smtp_setup_batch_msg(void)
1766 rmark reset_point = store_mark();
1768 /* Save the line count at the start of each transaction - single commands
1769 like HELO and RSET count as whole transactions. */
1771 bsmtp_transaction_linecount = receive_linecount;
1773 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1775 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
1776 reset_point = smtp_reset(reset_point); /* Reset for start of message */
1778 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1779 value. The values are 2 larger than the required yield of the function. */
1784 uschar *recipient = NULL;
1785 int start, end, sender_domain, recipient_domain;
1787 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1789 /* The HELO/EHLO commands set sender_address_helo if they have
1790 valid data; otherwise they are ignored, except that they do
1791 a reset of the state. */
1796 check_helo(smtp_cmd_data);
1800 cancel_cutthrough_connection(TRUE, US"RSET received");
1801 reset_point = smtp_reset(reset_point);
1802 bsmtp_transaction_linecount = receive_linecount;
1805 /* The MAIL FROM command requires an address as an operand. All we
1806 do here is to parse it for syntactic correctness. The form "<>" is
1807 a special case which converts into an empty string. The start/end
1808 pointers in the original are not used further for this address, as
1809 it is the canonical extracted address which is all that is kept. */
1812 smtp_mailcmd_count++; /* Count for no-mail log */
1814 /* The function moan_smtp_batch() does not return. */
1815 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1817 if (smtp_cmd_data[0] == 0)
1818 /* The function moan_smtp_batch() does not return. */
1819 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1821 /* Reset to start of message */
1823 cancel_cutthrough_connection(TRUE, US"MAIL received");
1824 reset_point = smtp_reset(reset_point);
1826 /* Apply SMTP rewrite */
1828 raw_sender = rewrite_existflags & rewrite_smtp
1829 /* deconst ok as smtp_cmd_data was not const */
1830 ? US rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL,
1831 FALSE, US"", global_rewrite_rules)
1834 /* Extract the address; the TRUE flag allows <> as valid */
1837 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1841 /* The function moan_smtp_batch() does not return. */
1842 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1844 sender_address = string_copy(raw_sender);
1846 /* Qualify unqualified sender addresses if permitted to do so. */
1849 && sender_address[0] != 0 && sender_address[0] != '@')
1850 if (f.allow_unqualified_sender)
1852 /* deconst ok as sender_address was not const */
1853 sender_address = US rewrite_address_qualify(sender_address, FALSE);
1854 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1855 "and rewritten\n", raw_sender);
1857 /* The function moan_smtp_batch() does not return. */
1859 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1864 /* The RCPT TO command requires an address as an operand. All we do
1865 here is to parse it for syntactic correctness. There may be any number
1866 of RCPT TO commands, specifying multiple senders. We build them all into
1867 a data structure that is in argc/argv format. The start/end values
1868 given by parse_extract_address are not used, as we keep only the
1869 extracted address. */
1872 if (!sender_address)
1873 /* The function moan_smtp_batch() does not return. */
1874 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1876 if (smtp_cmd_data[0] == 0)
1877 /* The function moan_smtp_batch() does not return. */
1878 moan_smtp_batch(smtp_cmd_buffer,
1879 "501 RCPT TO must have an address operand");
1881 /* Check maximum number allowed */
1883 if ( recipients_max_expanded > 0
1884 && recipients_count + 1 > recipients_max_expanded)
1885 /* The function moan_smtp_batch() does not return. */
1886 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1887 recipients_max_reject ? "552": "452");
1889 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1890 recipient address */
1892 recipient = rewrite_existflags & rewrite_smtp
1893 /* deconst ok as smtp_cmd_data was not const */
1894 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1895 global_rewrite_rules)
1898 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1899 &recipient_domain, FALSE);
1902 /* The function moan_smtp_batch() does not return. */
1903 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1905 /* If the recipient address is unqualified, qualify it if permitted. Then
1906 add it to the list of recipients. */
1908 if (!recipient_domain)
1909 if (f.allow_unqualified_recipient)
1911 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1913 /* deconst ok as recipient was not const */
1914 recipient = US rewrite_address_qualify(recipient, TRUE);
1916 /* The function moan_smtp_batch() does not return. */
1918 moan_smtp_batch(smtp_cmd_buffer,
1919 "501 recipient address must contain a domain");
1921 receive_add_recipient(recipient, -1);
1925 /* The DATA command is legal only if it follows successful MAIL FROM
1926 and RCPT TO commands. This function is complete when a valid DATA
1927 command is encountered. */
1930 if (!sender_address || recipients_count <= 0)
1931 /* The function moan_smtp_batch() does not return. */
1932 if (!sender_address)
1933 moan_smtp_batch(smtp_cmd_buffer,
1934 "503 MAIL FROM:<sender> command must precede DATA");
1936 moan_smtp_batch(smtp_cmd_buffer,
1937 "503 RCPT TO:<recipient> must precede DATA");
1940 done = 3; /* DATA successfully achieved */
1941 message_ended = END_NOTENDED; /* Indicate in middle of message */
1946 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1953 #ifndef DISABLE_WELLKNOWN
1956 bsmtp_transaction_linecount = receive_linecount;
1961 f.smtp_in_quit = TRUE;
1968 /* The function moan_smtp_batch() does not return. */
1969 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1974 /* The function moan_smtp_batch() does not return. */
1975 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1980 /* The function moan_smtp_batch() does not return. */
1981 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1986 return done - 2; /* Convert yield values */
1994 smtp_log_tls_fail(const uschar * errstr)
1996 const uschar * conn_info = smtp_get_connection_info();
1998 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
1999 /* I'd like to get separated H= here, but too hard for now */
2001 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2015 socklen_t len = sizeof(is_fastopen);
2017 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2018 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2020 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2025 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2026 f.tcp_in_fastopen = TRUE;
2029 else DEBUG(D_receive)
2030 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2032 # elif defined(TCP_INFO)
2033 struct tcp_info tinfo;
2034 socklen_t len = sizeof(tinfo);
2036 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2037 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2038 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2041 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2042 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2046 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2049 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2050 f.tcp_in_fastopen = TRUE;
2052 else DEBUG(D_receive)
2053 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2060 log_connect_tls_drop(const uschar * what, const uschar * log_msg)
2062 if (log_reject_target)
2065 uschar * tls = NULL;
2067 gstring * g = s_tlslog(NULL);
2068 uschar * tls = string_from_gstring(g);
2070 log_write(L_connection_reject,
2071 log_reject_target, "%s%s%s dropped by %s%s%s",
2072 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
2073 host_and_ident(TRUE),
2076 log_msg ? US": " : US"", log_msg);
2081 /*************************************************
2082 * Start an SMTP session *
2083 *************************************************/
2085 /* This function is called at the start of an SMTP session. Thereafter,
2086 smtp_setup_msg() is called to initiate each separate message. This
2087 function does host-specific testing, and outputs the banner line.
2090 Returns: FALSE if the session can not continue; something has
2091 gone wrong, or the connection to the host is blocked
2095 smtp_start_session(void)
2098 uschar *user_msg, *log_msg;
2103 gettimeofday(&smtp_connection_start, NULL);
2104 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2105 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2108 /* Default values for certain variables */
2110 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2111 smtp_mailcmd_count = 0;
2112 count_nonmail = TRUE_UNSET;
2113 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2114 smtp_delay_mail = smtp_rlm_base;
2115 fl.auth_advertised = FALSE;
2116 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2117 f.pipelining_enable = TRUE;
2118 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2119 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2121 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2122 authentication settings from -oMaa to remain in force. */
2124 if (!host_checking && !f.sender_host_notsocket)
2125 sender_host_auth_pubname = sender_host_authenticated = NULL;
2126 authenticated_by = NULL;
2129 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2130 tls_in.ourcert = tls_in.peercert = NULL;
2132 tls_in.ocsp = OCSP_NOT_REQ;
2133 fl.tls_advertised = FALSE;
2135 fl.dsn_advertised = FALSE;
2137 fl.smtputf8_advertised = FALSE;
2140 /* Reset ACL connection variables */
2144 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2146 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, GET_TAINTED);
2148 smtp_cmd_buffer[0] = 0;
2149 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2151 /* For batched input, the protocol setting can be overridden from the
2152 command line by a trusted caller. */
2154 if (smtp_batched_input)
2156 if (!received_protocol) received_protocol = US"local-bsmtp";
2159 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2160 reset later if any of EHLO/AUTH/STARTTLS are received. */
2164 (sender_host_address ? protocols : protocols_local) [pnormal];
2166 /* Set up the buffer for inputting using direct read() calls, and arrange to
2167 call the local functions instead of the standard C ones. */
2171 receive_getc = smtp_getc;
2172 receive_getbuf = smtp_getbuf;
2173 receive_get_cache = smtp_get_cache;
2174 receive_hasc = smtp_hasc;
2175 receive_ungetc = smtp_ungetc;
2176 receive_feof = smtp_feof;
2177 receive_ferror = smtp_ferror;
2178 lwr_receive_getc = NULL;
2179 lwr_receive_getbuf = NULL;
2180 lwr_receive_hasc = NULL;
2181 lwr_receive_ungetc = NULL;
2183 /* Set up the message size limit; this may be host-specific */
2185 GET_OPTION("message_size_limit");
2186 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2187 if (expand_string_message)
2189 if (thismessage_size_limit == -1)
2190 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2191 "%s", expand_string_message);
2193 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2194 "%s", expand_string_message);
2195 smtp_closedown(US"Temporary local problem - please try later");
2199 /* When a message is input locally via the -bs or -bS options, sender_host_
2200 unknown is set unless -oMa was used to force an IP address, in which case it
2201 is checked like a real remote connection. When -bs is used from inetd, this
2202 flag is not set, causing the sending host to be checked. The code that deals
2203 with IP source routing (if configured) is never required for -bs or -bS and
2204 the flag sender_host_notsocket is used to suppress it.
2206 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2207 reserve for certain hosts and/or networks. */
2209 if (!f.sender_host_unknown)
2212 BOOL reserved_host = FALSE;
2214 /* Look up IP options (source routing info) on the socket if this is not an
2215 -oMa "host", and if any are found, log them and drop the connection.
2217 Linux (and others now, see below) is different to everyone else, so there
2218 has to be some conditional compilation here. Versions of Linux before 2.1.15
2219 used a structure whose name was "options". Somebody finally realized that
2220 this name was silly, and it got changed to "ip_options". I use the
2221 newer name here, but there is a fudge in the script that sets up os.h
2222 to define a macro in older Linux systems.
2224 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2225 glibc 2, which has chosen ip_opts for the structure name. This is now
2226 really a glibc thing rather than a Linux thing, so the condition name
2227 has been changed to reflect this. It is relevant also to GNU/Hurd.
2229 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2230 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2231 a special macro defined in the os.h file.
2233 Some DGUX versions on older hardware appear not to support IP options at
2234 all, so there is now a general macro which can be set to cut out this
2237 How to do this properly in IPv6 is not yet known. */
2239 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2241 # ifdef GLIBC_IP_OPTIONS
2242 # if (!defined __GLIBC__) || (__GLIBC__ < 2)
2247 # elif defined DARWIN_IP_OPTIONS
2253 if (!host_checking && !f.sender_host_notsocket)
2256 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2257 struct ip_options *ipopt = store_get(optlen, GET_UNTAINTED);
2258 # elif OPTSTYLE == 2
2259 struct ip_opts ipoptblock;
2260 struct ip_opts *ipopt = &ipoptblock;
2261 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2263 struct ipoption ipoptblock;
2264 struct ipoption *ipopt = &ipoptblock;
2265 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2268 /* Occasional genuine failures of getsockopt() have been seen - for
2269 example, "reset by peer". Therefore, just log and give up on this
2270 call, unless the error is ENOPROTOOPT. This error is given by systems
2271 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2272 of writing. So for that error, carry on - we just can't do an IP options
2275 DEBUG(D_receive) debug_printf("checking for IP options\n");
2277 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2280 if (errno != ENOPROTOOPT)
2282 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2283 host_and_ident(FALSE), strerror(errno));
2284 smtp_printf("451 SMTP service not available\r\n", SP_NO_MORE);
2289 /* Deal with any IP options that are set. On the systems I have looked at,
2290 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2291 more logging data than will fit in big_buffer. Nevertheless, after somebody
2292 questioned this code, I've added in some paranoid checking. */
2294 else if (optlen > 0)
2296 uschar * p = big_buffer;
2297 uschar * pend = big_buffer + big_buffer_size;
2300 struct in_addr addr;
2303 uschar * optstart = US (ipopt->__data);
2304 # elif OPTSTYLE == 2
2305 uschar * optstart = US (ipopt->ip_opts);
2307 uschar * optstart = US (ipopt->ipopt_list);
2310 DEBUG(D_receive) debug_printf("IP options exist\n");
2312 Ustrcpy(p, "IP options on incoming call:");
2315 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2330 string_format(p, pend-p, " %s [@%s",
2331 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2332 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr)))))
2333 # elif OPTSTYLE == 2
2334 string_format(p, pend-p, " %s [@%s",
2335 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2336 inet_ntoa(ipopt->ip_dst))
2338 string_format(p, pend-p, " %s [@%s",
2339 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2340 inet_ntoa(ipopt->ipopt_dst))
2349 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2351 while (optcount-- > 0)
2353 memcpy(&addr, adptr, sizeof(addr));
2354 if (!string_format(p, pend - p - 1, "%s%s",
2355 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2361 adptr += sizeof(struct in_addr);
2369 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2372 for (int i = 0; i < opt[1]; i++)
2373 p += sprintf(CS p, "%2.2x ", opt[i]);
2381 log_write(0, LOG_MAIN, "%s", big_buffer);
2383 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2385 log_write(0, LOG_MAIN|LOG_REJECT,
2386 "connection from %s refused (IP options)", host_and_ident(FALSE));
2388 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2392 /* Length of options = 0 => there are no options */
2394 else DEBUG(D_receive) debug_printf("no IP options found\n");
2396 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2398 /* Set keep-alive in socket options. The option is on by default. This
2399 setting is an attempt to get rid of some hanging connections that stick in
2400 read() when the remote end (usually a dialup) goes away. */
2402 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2403 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2405 /* If the current host matches host_lookup, set the name by doing a
2406 reverse lookup. On failure, sender_host_name will be NULL and
2407 host_lookup_failed will be TRUE. This may or may not be serious - optional
2410 if (verify_check_host(&host_lookup) == OK)
2412 (void)host_name_lookup();
2413 host_build_sender_fullhost();
2416 /* Delay this until we have the full name, if it is looked up. */
2418 set_process_info("handling incoming connection from %s",
2419 host_and_ident(FALSE));
2421 /* Expand smtp_receive_timeout, if needed */
2423 if (smtp_receive_timeout_s)
2426 if ( !(exp = expand_string(smtp_receive_timeout_s))
2428 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2430 log_write(0, LOG_MAIN|LOG_PANIC,
2431 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2434 /* Test for explicit connection rejection */
2436 if (verify_check_host(&host_reject_connection) == OK)
2438 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2439 "from %s (host_reject_connection)", host_and_ident(FALSE));
2441 if (!tls_in.on_connect)
2443 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2447 /* Test with TCP Wrappers if so configured. There is a problem in that
2448 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2449 such as disks dying. In these cases, it is desirable to reject with a 4xx
2450 error instead of a 5xx error. There isn't a "right" way to detect such
2451 problems. The following kludge is used: errno is zeroed before calling
2452 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2453 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2456 #ifdef USE_TCP_WRAPPERS
2458 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2459 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2460 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2461 expand_string_message);
2463 if (!hosts_ctl(tcp_wrappers_name,
2464 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2465 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2466 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2468 if (errno == 0 || errno == ENOENT)
2470 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2471 log_write(L_connection_reject,
2472 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2473 "(tcp wrappers)", host_and_ident(FALSE));
2474 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2478 int save_errno = errno;
2479 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2480 "errno value %d\n", save_errno);
2481 log_write(L_connection_reject,
2482 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2483 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2484 smtp_printf("451 Temporary local problem - please try later\r\n", SP_NO_MORE);
2490 /* Check for reserved slots. The value of smtp_accept_count has already been
2491 incremented to include this process. */
2493 if (smtp_accept_max > 0 &&
2494 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2496 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2498 log_write(L_connection_reject,
2499 LOG_MAIN, "temporarily refused connection from %s: not in "
2500 "reserve list: connected=%d max=%d reserve=%d%s",
2501 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2502 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2503 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2504 "please try again later\r\n", SP_NO_MORE, smtp_active_hostname);
2507 reserved_host = TRUE;
2510 /* If a load level above which only messages from reserved hosts are
2511 accepted is set, check the load. For incoming calls via the daemon, the
2512 check is done in the superior process if there are no reserved hosts, to
2513 save a fork. In all cases, the load average will already be available
2514 in a global variable at this point. */
2516 if (smtp_load_reserve >= 0 &&
2517 load_average > smtp_load_reserve &&
2519 verify_check_host(&smtp_reserve_hosts) != OK)
2521 log_write(L_connection_reject,
2522 LOG_MAIN, "temporarily refused connection from %s: not in "
2523 "reserve list and load average = %.2f", host_and_ident(FALSE),
2524 (double)load_average/1000.0);
2525 smtp_printf("421 %s: Too much load; please try again later\r\n", SP_NO_MORE,
2526 smtp_active_hostname);
2530 /* Determine whether unqualified senders or recipients are permitted
2531 for this host. Unfortunately, we have to do this every time, in order to
2532 set the flags so that they can be inspected when considering qualifying
2533 addresses in the headers. For a site that permits no qualification, this
2534 won't take long, however. */
2536 f.allow_unqualified_sender =
2537 verify_check_host(&sender_unqualified_hosts) == OK;
2539 f.allow_unqualified_recipient =
2540 verify_check_host(&recipient_unqualified_hosts) == OK;
2542 /* Determine whether HELO/EHLO is required for this host. The requirement
2543 can be hard or soft. */
2545 fl.helo_verify_required = verify_check_host(&helo_verify_hosts) == OK;
2546 if (!fl.helo_verify_required)
2547 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2549 /* Determine whether this hosts is permitted to send syntactic junk
2550 after a HELO or EHLO command. */
2552 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2555 /* Expand recipients_max, if needed */
2557 uschar * rme = expand_string(recipients_max);
2558 recipients_max_expanded = atoi(CCS rme);
2560 /* For batch SMTP input we are now done. */
2562 if (smtp_batched_input) return TRUE;
2564 #if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS) || defined(EXPERIMENTAL_XCLIENT)
2565 proxy_session = FALSE;
2568 #ifdef SUPPORT_PROXY
2569 /* If valid Proxy Protocol source is connecting, set up session.
2570 Failure will not allow any SMTP function other than QUIT. */
2572 f.proxy_session_failed = FALSE;
2573 if (proxy_protocol_host())
2575 os_non_restarting_signal(SIGALRM, command_timeout_handler);
2576 proxy_protocol_setup();
2580 /* Run the connect ACL if it exists */
2583 GET_OPTION("acl_smtp_connect");
2584 if (acl_smtp_connect)
2587 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2591 if (tls_in.on_connect)
2592 log_connect_tls_drop(US"'connect' ACL", log_msg);
2595 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2600 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2601 smtps port for use with older style SSL MTAs. */
2604 if (tls_in.on_connect)
2606 if (tls_server_start(&user_msg) != OK)
2607 return smtp_log_tls_fail(user_msg);
2608 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
2612 /* Output the initial message for a two-way SMTP connection. It may contain
2613 newlines, which then cause a multi-line response to be given. */
2615 code = US"220"; /* Default status code */
2616 esc = US""; /* Default extended status code */
2617 esclen = 0; /* Length of esc */
2623 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2627 esclen = codelen - 4;
2632 GET_OPTION("smtp_banner");
2633 if (!(s = expand_string(smtp_banner)))
2635 log_write(0, f.expand_string_forcedfail ? LOG_MAIN : LOG_MAIN|LOG_PANIC_DIE,
2636 "Expansion of \"%s\" (smtp_banner) failed: %s",
2637 smtp_banner, expand_string_message);
2638 /* for force-fail */
2640 if (tls_in.on_connect) tls_close(NULL, TLS_SHUTDOWN_WAIT);
2646 /* Remove any terminating newlines; might as well remove trailing space too */
2649 while (p > s && isspace(p[-1])) p--;
2650 s = string_copyn(s, p-s);
2652 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2653 is all contained in a single IP packet. The original code wrote out the
2654 greeting using several calls to fprint/fputc, and on busy servers this could
2655 cause it to be split over more than one packet - which caused CC:Mail to fall
2656 over when it got the second part of the greeting after sending its first
2657 command. Sigh. To try to avoid this, build the complete greeting message
2658 first, and output it in one fell swoop. This gives a better chance of it
2659 ending up as a single packet. */
2661 ss = string_get(256);
2664 do /* At least once, in case we have an empty string */
2667 uschar *linebreak = Ustrchr(p, '\n');
2668 ss = string_catn(ss, code, 3);
2672 ss = string_catn(ss, US" ", 1);
2676 len = linebreak - p;
2677 ss = string_catn(ss, US"-", 1);
2679 ss = string_catn(ss, esc, esclen);
2680 ss = string_catn(ss, p, len);
2681 ss = string_catn(ss, US"\r\n", 2);
2687 /* Before we write the banner, check that there is no input pending, unless
2688 this synchronisation check is disabled. */
2690 #ifndef DISABLE_PIPE_CONNECT
2691 fl.pipe_connect_acceptable =
2692 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
2695 if (fl.pipe_connect_acceptable)
2696 f.smtp_in_early_pipe_used = TRUE;
2702 unsigned n = smtp_inend - smtp_inptr;
2703 if (n > 128) n = 128;
2705 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2706 "synchronization error (input sent without waiting for greeting): "
2707 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2708 string_printing(string_copyn(smtp_inptr, n)));
2709 smtp_printf("554 SMTP synchronization error\r\n", SP_NO_MORE);
2713 /* Now output the banner */
2714 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
2717 #ifndef DISABLE_PIPE_CONNECT
2718 fl.pipe_connect_acceptable && pipeline_connect_sends(),
2724 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2725 handshake arrived. If so we must have managed a TFO. */
2728 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
2738 /*************************************************
2739 * Handle SMTP syntax and protocol errors *
2740 *************************************************/
2742 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2743 to do so. Then transmit the error response. The return value depends on the
2744 number of syntax and protocol errors in this SMTP session.
2747 type error type, given as a log flag bit
2748 code response code; <= 0 means don't send a response
2749 data data to reflect in the response (can be NULL)
2750 errmess the error message
2752 Returns: -1 limit of syntax/protocol errors NOT exceeded
2753 +1 limit of syntax/protocol errors IS exceeded
2755 These values fit in with the values of the "done" variable in the main
2756 processing loop in smtp_setup_msg(). */
2759 synprot_error(int type, int code, uschar *data, uschar *errmess)
2763 #ifndef DISABLE_EVENT
2764 event_raise(event_action,
2765 L_smtp_syntax_error ? US"smtp:fail:syntax" : US"smtp:fail:protocol",
2769 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2770 type == L_smtp_syntax_error ? "syntax" : "protocol",
2771 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2773 if (++synprot_error_count > smtp_max_synprot_errors)
2776 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2777 "syntax or protocol errors (last command was \"%s\", %Y)",
2778 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
2785 smtp_printf("%d%c%s%s%s\r\n", SP_NO_MORE, code, yield == 1 ? '-' : ' ',
2786 data ? data : US"", data ? US": " : US"", errmess);
2788 smtp_printf("%d Too many syntax or protocol errors\r\n", SP_NO_MORE, code);
2797 /*************************************************
2798 * Send SMTP response, possibly multiline *
2799 *************************************************/
2801 /* There are, it seems, broken clients out there that cannot handle multiline
2802 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2803 output nothing for non-final calls, and only the first line for anything else.
2806 code SMTP code, may involve extended status codes
2807 codelen length of smtp code; if > 4 there's an ESC
2808 final FALSE if the last line isn't the final line
2809 msg message text, possibly containing newlines
2815 smtp_respond(uschar * code, int codelen, BOOL final, uschar * msg)
2820 if (!final && f.no_multiline_responses) return;
2825 esclen = codelen - 4;
2828 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2829 have had the same. Note: this code is also present in smtp_printf(). It would
2830 be tidier to have it only in one place, but when it was added, it was easier to
2831 do it that way, so as not to have to mess with the code for the RCPT command,
2832 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2834 if (fl.rcpt_in_progress)
2836 if (!rcpt_smtp_response)
2837 rcpt_smtp_response = string_copy(msg);
2838 else if (fl.rcpt_smtp_response_same &&
2839 Ustrcmp(rcpt_smtp_response, msg) != 0)
2840 fl.rcpt_smtp_response_same = FALSE;
2841 fl.rcpt_in_progress = FALSE;
2844 /* Now output the message, splitting it up into multiple lines if necessary.
2845 We only handle pipelining these responses as far as nonfinal/final groups,
2846 not the whole MAIL/RCPT/DATA response set. */
2849 if (!(nl = Ustrchr(msg, '\n')))
2851 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
2854 else if (nl[1] == 0 || f.no_multiline_responses)
2856 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
2857 (int)(nl - msg), msg);
2862 smtp_printf("%.3s-%.*s%.*s\r\n", SP_MORE, code, esclen, esc, (int)(nl - msg), msg);
2864 Uskip_whitespace(&msg);
2871 /*************************************************
2872 * Parse user SMTP message *
2873 *************************************************/
2875 /* This function allows for user messages overriding the response code details
2876 by providing a suitable response code string at the start of the message
2877 user_msg. Check the message for starting with a response code and optionally an
2878 extended status code. If found, check that the first digit is valid, and if so,
2879 change the code pointer and length to use the replacement. An invalid code
2880 causes a panic log; in this case, if the log messages is the same as the user
2881 message, we must also adjust the value of the log message to show the code that
2882 is actually going to be used (the original one).
2884 This function is global because it is called from receive.c as well as within
2887 Note that the code length returned includes the terminating whitespace
2888 character, which is always included in the regex match.
2891 code SMTP code, may involve extended status codes
2892 codelen length of smtp code; if > 4 there's an ESC
2894 log_msg optional log message, to be adjusted with the new SMTP code
2895 check_valid if true, verify the response code
2901 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2907 if (!msg || !*msg || !regex_match(regex_smtp_code, *msg, -1, &match))
2910 len = Ustrlen(match);
2911 if (check_valid && (*msg)[0] != (*code)[0])
2913 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2914 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2915 if (log_msg && *log_msg == *msg)
2916 *log_msg = string_sprintf("%s %s", *code, *log_msg + len);
2921 *codelen = len; /* Includes final space */
2923 *msg += len; /* Chop the code off the message */
2930 /*************************************************
2931 * Handle an ACL failure *
2932 *************************************************/
2934 /* This function is called when acl_check() fails. As well as calls from within
2935 this module, it is called from receive.c for an ACL after DATA. It sorts out
2936 logging the incident, and sends the error response. A message containing
2937 newlines is turned into a multiline SMTP response, but for logging, only the
2940 There's a table of default permanent failure response codes to use in
2941 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2942 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2943 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2944 state, because there are broken clients that try VRFY before RCPT. A 5xx
2945 response should be given only when the address is positively known to be
2946 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2947 no explicit code, but if there is one we let it know best.
2948 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2950 From Exim 4.63, it is possible to override the response code details by
2951 providing a suitable response code string at the start of the message provided
2952 in user_msg. The code's first digit is checked for validity.
2955 where where the ACL was called from
2957 user_msg a message that can be included in an SMTP response
2958 log_msg a message for logging
2960 Returns: 0 in most cases
2961 2 if the failure code was FAIL_DROP, in which case the
2962 SMTP connection should be dropped (this value fits with the
2963 "done" variable in smtp_setup_msg() below)
2967 smtp_handle_acl_fail(int where, int rc, uschar * user_msg, uschar * log_msg)
2969 BOOL drop = rc == FAIL_DROP;
2973 uschar *sender_info = US"";
2976 if (drop) rc = FAIL;
2978 /* Set the default SMTP code, and allow a user message to change it. */
2980 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2981 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2982 where != ACL_WHERE_VRFY);
2984 /* Get info for logging.
2985 We used to have sender_address here; however, there was a bug that was not
2986 updating sender_address after a rewrite during a verify. When this bug was
2987 fixed, sender_address at this point became the rewritten address. I'm not sure
2988 this is what should be logged, so I've changed to logging the unrewritten
2989 address to retain backward compatibility. */
2993 #ifdef WITH_CONTENT_SCAN
2994 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
2996 case ACL_WHERE_PREDATA: what = US"DATA"; break;
2997 case ACL_WHERE_DATA: what = US"after DATA"; break;
2998 #ifndef DISABLE_PRDR
2999 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
3003 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
3006 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
3008 uschar * s = smtp_cmd_data;
3010 lim = s - smtp_cmd_data; /* stop after method */
3012 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
3017 case ACL_WHERE_RCPT:
3018 case ACL_WHERE_DATA:
3019 #ifdef WITH_CONTENT_SCAN
3020 case ACL_WHERE_MIME:
3022 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3023 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3024 sender_host_authenticated ? US" A=" : US"",
3025 sender_host_authenticated ? sender_host_authenticated : US"",
3026 sender_host_authenticated && authenticated_id ? US":" : US"",
3027 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3032 /* If there's been a sender verification failure with a specific message, and
3033 we have not sent a response about it yet, do so now, as a preliminary line for
3034 failures, but not defers. However, always log it for defer, and log it for fail
3035 unless the sender_verify_fail log selector has been turned off. */
3037 if (sender_verified_failed &&
3038 !testflag(sender_verified_failed, af_sverify_told))
3040 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3041 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3043 setflag(sender_verified_failed, af_sverify_told);
3045 if (rc != FAIL || LOGGING(sender_verify_fail))
3046 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3047 host_and_ident(TRUE),
3048 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3049 sender_verified_failed->address,
3050 (sender_verified_failed->message == NULL)? US"" :
3051 string_sprintf(": %s", sender_verified_failed->message));
3053 if (rc == FAIL && sender_verified_failed->user_message)
3054 smtp_respond(smtp_code, codelen, SR_NOT_FINAL, string_sprintf(
3055 testflag(sender_verified_failed, af_verify_pmfail)?
3056 "Postmaster verification failed while checking <%s>\n%s\n"
3057 "Several RFCs state that you are required to have a postmaster\n"
3058 "mailbox for each mail domain. This host does not accept mail\n"
3059 "from domains whose servers reject the postmaster address."
3061 testflag(sender_verified_failed, af_verify_nsfail)?
3062 "Callback setup failed while verifying <%s>\n%s\n"
3063 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3064 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3065 "RFC requirements, and stops you from receiving standard bounce\n"
3066 "messages. This host does not accept mail from domains whose servers\n"
3069 "Verification failed for <%s>\n%s",
3070 sender_verified_failed->address,
3071 sender_verified_failed->user_message));
3073 fl.rcpt_in_progress = save_rcpt_in_progress;
3076 /* Sort out text for logging */
3078 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3079 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3081 /* Send permanent failure response to the command, but the code used isn't
3082 always a 5xx one - see comments at the start of this function. If the original
3083 rc was FAIL_DROP we drop the connection and yield 2. */
3086 smtp_respond(smtp_code, codelen, SR_FINAL,
3087 user_msg ? user_msg : US"Administrative prohibition");
3089 /* Send temporary failure response to the command. Don't give any details,
3090 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3091 verb, and for a header verify when smtp_return_error_details is set.
3093 This conditional logic is all somewhat of a mess because of the odd
3094 interactions between temp_details and return_error_details. One day it should
3095 be re-implemented in a tidier fashion. */
3098 if (f.acl_temp_details && user_msg)
3100 if ( smtp_return_error_details
3101 && sender_verified_failed
3102 && sender_verified_failed->message
3104 smtp_respond(smtp_code, codelen, SR_NOT_FINAL, sender_verified_failed->message);
3106 smtp_respond(smtp_code, codelen, SR_FINAL, user_msg);
3109 smtp_respond(smtp_code, codelen, SR_FINAL,
3110 US"Temporary local problem - please try later");
3112 /* Log the incident to the logs that are specified by log_reject_target
3113 (default main, reject). This can be empty to suppress logging of rejections. If
3114 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3115 is closing if required and return 2. */
3117 if (log_reject_target)
3120 gstring * g = s_tlslog(NULL);
3121 uschar * tls = string_from_gstring(g);
3122 if (!tls) tls = US"";
3124 uschar * tls = US"";
3126 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3127 log_reject_target, "%s%s%s %s%srejected %s%s",
3128 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3129 host_and_ident(TRUE),
3132 rc == FAIL ? US"" : US"temporarily ",
3136 if (!drop) return 0;
3138 log_close_event(US"by DROP in ACL");
3140 /* Run the not-quit ACL, but without any custom messages. This should not be a
3141 problem, because we get here only if some other ACL has issued "drop", and
3142 in that case, *its* custom messages will have been used above. */
3144 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3146 /* An overenthusiastic fail2ban/iptables implimentation has been seen to result
3147 in the TCP conn staying open, and retrying, despite this process exiting. A
3148 malicious client could possibly do the same, tying up server netowrking
3149 resources. Close the socket explicitly to try to avoid that (there's a note in
3150 the Linux socket(7) manpage, SO_LINGER para, to the effect that exim() without
3151 close() results in the socket always lingering). */
3153 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3154 DEBUG(D_any) debug_printf_indent("SMTP(close)>>\n");
3155 (void) fclose(smtp_in);
3156 (void) fclose(smtp_out);
3164 /*************************************************
3165 * Handle SMTP exit when QUIT is not given *
3166 *************************************************/
3168 /* This function provides a logging/statistics hook for when an SMTP connection
3169 is dropped on the floor or the other end goes away. It's a global function
3170 because it's called from receive.c as well as this module. As well as running
3171 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3172 response, either with a custom message from the ACL, or using a default. There
3173 is one case, however, when no message is output - after "drop". In that case,
3174 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3175 passed to this function.
3177 In case things go wrong while processing this function, causing an error that
3178 may re-enter this function, there is a recursion check.
3181 reason What $smtp_notquit_reason will be set to in the ACL;
3182 if NULL, the ACL is not run
3183 code The error code to return as part of the response
3184 defaultrespond The default message if there's no user_msg
3190 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3193 uschar *user_msg = NULL;
3194 uschar *log_msg = NULL;
3196 /* Check for recursive call */
3198 if (fl.smtp_exit_function_called)
3200 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3204 fl.smtp_exit_function_called = TRUE;
3206 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3208 GET_OPTION("acl_smtp_notquit");
3209 if (acl_smtp_notquit && reason)
3211 smtp_notquit_reason = reason;
3212 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3213 &log_msg)) == ERROR)
3214 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3218 /* If the connection was dropped, we certainly are no longer talking TLS */
3219 tls_in.active.sock = -1;
3221 /* Write an SMTP response if we are expected to give one. As the default
3222 responses are all internal, they should be reasonable size. */
3224 if (code && defaultrespond)
3227 smtp_respond(code, 3, SR_FINAL, user_msg);
3233 va_start(ap, defaultrespond);
3234 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3236 smtp_printf("%s %Y\r\n", SP_NO_MORE, code, g);
3245 /*************************************************
3246 * Verify HELO argument *
3247 *************************************************/
3249 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3250 matched. It is also called from ACL processing if verify = helo is used and
3251 verification was not previously tried (i.e. helo_try_verify_hosts was not
3252 matched). The result of its processing is to set helo_verified and
3253 helo_verify_failed. These variables should both be FALSE for this function to
3256 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3257 for IPv6 ::ffff: literals.
3260 Returns: TRUE if testing was completed;
3261 FALSE on a temporary failure
3265 smtp_verify_helo(void)
3269 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3272 if (sender_helo_name == NULL)
3274 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3277 /* Deal with the case of -bs without an IP address */
3279 else if (sender_host_address == NULL)
3281 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3282 f.helo_verified = TRUE;
3285 /* Deal with the more common case when there is a sending IP address */
3287 else if (sender_helo_name[0] == '[')
3289 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3290 Ustrlen(sender_host_address)) == 0;
3293 if (!f.helo_verified)
3295 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3296 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3297 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3302 { if (f.helo_verified) debug_printf("matched host address\n"); }
3305 /* Do a reverse lookup if one hasn't already given a positive or negative
3306 response. If that fails, or the name doesn't match, try checking with a forward
3311 if (sender_host_name == NULL && !host_lookup_failed)
3312 yield = host_name_lookup() != DEFER;
3314 /* If a host name is known, check it and all its aliases. */
3316 if (sender_host_name)
3317 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3319 sender_helo_dnssec = sender_host_dnssec;
3320 HDEBUG(D_receive) debug_printf("matched host name\n");
3324 uschar **aliases = sender_host_aliases;
3326 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3328 sender_helo_dnssec = sender_host_dnssec;
3332 HDEBUG(D_receive) if (f.helo_verified)
3333 debug_printf("matched alias %s\n", *(--aliases));
3336 /* Final attempt: try a forward lookup of the helo name */
3338 if (!f.helo_verified)
3342 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3344 {.request = US"*", .require = US""};
3346 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3348 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3349 NULL, NULL, NULL, &d, NULL, NULL);
3350 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3351 for (host_item * hh = &h; hh; hh = hh->next)
3352 if (Ustrcmp(hh->address, sender_host_address) == 0)
3354 f.helo_verified = TRUE;
3355 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3357 debug_printf("IP address for %s matches calling address\n"
3358 "Forward DNS security status: %sverified\n",
3359 sender_helo_name, sender_helo_dnssec ? "" : "un");
3365 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3372 /*************************************************
3373 * Send user response message *
3374 *************************************************/
3376 /* This function is passed a default response code and a user message. It calls
3377 smtp_message_code() to check and possibly modify the response code, and then
3378 calls smtp_respond() to transmit the response. I put this into a function
3379 just to avoid a lot of repetition.
3382 code the response code
3383 user_msg the user message
3389 smtp_user_msg(uschar * code, uschar * user_msg)
3392 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3393 smtp_respond(code, len, SR_FINAL, user_msg);
3399 smtp_in_auth(auth_instance *au, uschar ** smtp_resp, uschar ** errmsg)
3401 const uschar *set_id = NULL;
3404 /* Set up globals for error messages */
3406 authenticator_name = au->drinst.name;
3407 driver_srcfile = au->drinst.srcfile;
3408 driver_srcline = au->drinst.srcline;
3410 /* Run the checking code, passing the remainder of the command line as
3411 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3412 it as the only set numerical variable. The authenticator may set $auth<n>
3413 and also set other numeric variables. The $auth<n> variables are preferred
3414 nowadays; the numerical variables remain for backwards compatibility.
3416 Afterwards, have a go at expanding the set_id string, even if
3417 authentication failed - for bad passwords it can be useful to log the
3418 userid. On success, require set_id to expand and exist, and put it in
3419 authenticated_id. Save this in permanent store, as the working store gets
3420 reset at HELO, RSET, etc. */
3422 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3424 expand_nlength[0] = 0; /* $0 contains nothing */
3427 auth_info * ai = au->drinst.info;
3428 rc = (ai->servercode)(au, smtp_cmd_data);
3430 if (au->set_id) set_id = expand_string(au->set_id);
3431 expand_nmax = -1; /* Reset numeric variables */
3432 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3433 driver_srcfile = authenticator_name = NULL; driver_srcline = 0;
3435 /* The value of authenticated_id is stored in the spool file and printed in
3436 log lines. It must not contain binary zeros or newline characters. In
3437 normal use, it never will, but when playing around or testing, this error
3438 can (did) happen. To guard against this, ensure that the id contains only
3439 printing characters. */
3441 if (set_id) set_id = string_printing(set_id);
3443 /* For the non-OK cases, set up additional logging data if set_id
3447 set_id = set_id && *set_id
3448 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3450 /* Switch on the result */
3455 if (!au->set_id || set_id) /* Complete success */
3457 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3458 sender_host_authenticated = au->drinst.name;
3459 sender_host_auth_pubname = au->public_name;
3460 authentication_failed = FALSE;
3461 authenticated_fail_id = NULL; /* Impossible to already be set? */
3464 (sender_host_address ? protocols : protocols_local)
3465 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3466 *smtp_resp = *errmsg = US"235 Authentication succeeded";
3467 authenticated_by = au;
3471 /* Authentication succeeded, but we failed to expand the set_id string.
3472 Treat this as a temporary error. */
3474 auth_defer_msg = expand_string_message;
3478 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3479 *smtp_resp = string_sprintf("435 Unable to authenticate at present%s",
3480 auth_defer_user_msg);
3481 *errmsg = string_sprintf("435 Unable to authenticate at present%s: %s",
3482 set_id, auth_defer_msg);
3486 *smtp_resp = *errmsg = US"501 Invalid base64 data";
3490 *smtp_resp = *errmsg = US"501 Authentication cancelled";
3494 *smtp_resp = *errmsg = US"553 Initial data not expected";
3498 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3499 *smtp_resp = US"535 Incorrect authentication data";
3500 *errmsg = string_sprintf("535 Incorrect authentication data%s", set_id);
3504 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3505 *smtp_resp = US"435 Internal error";
3506 *errmsg = string_sprintf("435 Internal error%s: return %d from authentication "
3507 "check", set_id, rc);
3519 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3522 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3524 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3526 rd = Ustrlen(recipient) + 1;
3527 /* deconst ok as *recipient was not const */
3528 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3531 smtp_printf("501 %s: recipient address must contain a domain\r\n", SP_NO_MORE,
3533 log_write(L_smtp_syntax_error,
3534 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3535 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3543 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3546 f.smtp_in_quit = TRUE;
3547 incomplete_transaction_log(US"QUIT");
3548 GET_OPTION("acl_smtp_quit");
3550 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3552 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3555 #ifdef EXIM_TCP_CORK
3556 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
3560 smtp_respond(US"221", 3, SR_FINAL, *user_msgp);
3562 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
3564 #ifdef SERVERSIDE_CLOSE_NOWAIT
3565 # ifndef DISABLE_TLS
3566 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3569 log_close_event(US"by QUIT");
3572 # ifndef DISABLE_TLS
3573 tls_close(NULL, TLS_SHUTDOWN_WAIT);
3576 log_close_event(US"by QUIT");
3578 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
3579 The socket should become readble (though with no data) */
3581 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3582 #endif /*!SERVERSIDE_CLOSE_NOWAIT*/
3587 smtp_rset_handler(void)
3590 incomplete_transaction_log(US"RSET");
3591 smtp_printf("250 Reset OK\r\n", SP_NO_MORE);
3592 cmd_list[CL_RSET].is_mail_cmd = FALSE;
3593 if (chunking_state > CHUNKING_OFFERED)
3594 chunking_state = CHUNKING_OFFERED;
3598 #ifndef DISABLE_WELLKNOWN
3600 smtp_wellknown_handler(void)
3602 if (verify_check_host(&wellknown_advertise_hosts) != FAIL)
3604 GET_OPTION("acl_smtp_wellknown");
3605 if (acl_smtp_wellknown)
3607 uschar * user_msg = NULL, * log_msg;
3610 if ((rc = acl_check(ACL_WHERE_WELLKNOWN, NULL, acl_smtp_wellknown,
3611 &user_msg, &log_msg)) != OK)
3612 return smtp_handle_acl_fail(ACL_WHERE_WELLKNOWN, rc, user_msg, log_msg);
3613 else if (!wellknown_response)
3614 return smtp_handle_acl_fail(ACL_WHERE_WELLKNOWN, ERROR, user_msg, log_msg);
3615 smtp_user_msg(US"250", wellknown_response);
3620 smtp_printf("554 not permitted\r\n", SP_NO_MORE);
3621 log_write(0, LOG_MAIN|LOG_REJECT, "rejected \"%s\" from %s",
3622 smtp_cmd_buffer, sender_helo_name, host_and_ident(FALSE));
3629 expand_mailmax(const uschar * s)
3631 if (!(s = expand_cstring(s)))
3632 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
3633 return *s ? Uatoi(s) : 0;
3636 /*************************************************
3637 * Initialize for SMTP incoming message *
3638 *************************************************/
3640 /* This function conducts the initial dialogue at the start of an incoming SMTP
3641 message, and builds a list of recipients. However, if the incoming message
3642 is part of a batch (-bS option) a separate function is called since it would
3643 be messy having tests splattered about all over this function. This function
3644 therefore handles the case where interaction is occurring. The input and output
3645 files are set up in smtp_in and smtp_out.
3647 The global recipients_list is set to point to a vector of recipient_item
3648 blocks, whose number is given by recipients_count. This is extended by the
3649 receive_add_recipient() function. The global variable sender_address is set to
3650 the sender's address. The yield is +1 if a message has been successfully
3651 started, 0 if a QUIT command was encountered or the connection was refused from
3652 the particular host, or -1 if the connection was lost.
3656 Returns: > 0 message successfully started (reached DATA)
3657 = 0 QUIT read or end of file reached or call refused
3662 smtp_setup_msg(void)
3665 BOOL toomany = FALSE;
3666 BOOL discarded = FALSE;
3667 BOOL last_was_rej_mail = FALSE;
3668 BOOL last_was_rcpt = FALSE;
3669 rmark reset_point = store_mark();
3671 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3673 /* Reset for start of new message. We allow one RSET not to be counted as a
3674 nonmail command, for those MTAs that insist on sending it between every
3675 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3676 TLS between messages (an Exim client may do this if it has messages queued up
3677 for the host). Note: we do NOT reset AUTH at this point. */
3679 reset_point = smtp_reset(reset_point);
3680 message_ended = END_NOTSTARTED;
3682 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3684 cmd_list[CL_RSET].is_mail_cmd = TRUE;
3685 cmd_list[CL_HELO].is_mail_cmd = TRUE;
3686 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
3688 cmd_list[CL_STLS].is_mail_cmd = TRUE;
3691 if (lwr_receive_getc != NULL)
3693 /* This should have already happened, but if we've gotten confused,
3694 force a reset here. */
3695 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
3696 bdat_pop_receive_functions();
3699 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3701 had_command_sigterm = 0;
3702 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3704 /* Batched SMTP is handled in a different function. */
3706 if (smtp_batched_input) return smtp_setup_batch_msg();
3709 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3710 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3711 US &off, sizeof(off));
3714 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3715 value. The values are 2 larger than the required yield of the function. */
3719 const uschar **argv;
3720 uschar *etrn_command;
3721 uschar *etrn_serialize_key;
3723 uschar *log_msg, *smtp_code;
3724 uschar *user_msg = NULL;
3725 uschar *recipient = NULL;
3726 uschar *hello = NULL;
3728 BOOL was_rej_mail = FALSE;
3729 BOOL was_rcpt = FALSE;
3730 void (*oldsignal)(int);
3732 int start, end, sender_domain, recipient_domain;
3734 uschar * orcpt = NULL;
3739 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3740 if ( tls_in.active.sock >= 0
3742 && tls_in.certificate_verified
3743 && cmd_list[CL_TLAU].is_mail_cmd
3746 cmd_list[CL_TLAU].is_mail_cmd = FALSE;
3748 for (auth_instance * au = auths; au; au = au->drinst.next)
3749 if (strcmpic(US"tls", au->drinst.driver_name) == 0)
3751 GET_OPTION("acl_smtp_auth");
3753 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3754 &user_msg, &log_msg)) != OK
3756 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3759 smtp_cmd_data = NULL;
3761 if (smtp_in_auth(au, &s, &ss) == OK)
3762 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3765 DEBUG(D_auth) debug_printf("tls auth not succeeded\n");
3766 #ifndef DISABLE_EVENT
3768 uschar * save_name = sender_host_authenticated, * logmsg;
3769 sender_host_authenticated = au->drinst.name;
3770 if ((logmsg = event_raise(event_action, US"auth:fail", s, NULL)))
3771 log_write(0, LOG_MAIN, "%s", logmsg);
3772 sender_host_authenticated = save_name;
3782 switch(smtp_read_command(
3783 #ifndef DISABLE_PIPE_CONNECT
3784 !fl.pipe_connect_acceptable,
3788 GETC_BUFFER_UNLIMITED))
3790 /* The AUTH command is not permitted to occur inside a transaction, and may
3791 occur successfully only once per connection. Actually, that isn't quite
3792 true. When TLS is started, all previous information about a connection must
3793 be discarded, so a new AUTH is permitted at that time.
3795 AUTH may only be used when it has been advertised. However, it seems that
3796 there are clients that send AUTH when it hasn't been advertised, some of
3797 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3798 So there's a get-out that allows this to happen.
3800 AUTH is initially labelled as a "nonmail command" so that one occurrence
3801 doesn't get counted. We change the label here so that multiple failing
3802 AUTHS will eventually hit the nonmail threshold. */
3806 authentication_failed = TRUE;
3807 cmd_list[CL_AUTH].is_mail_cmd = FALSE;
3809 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
3811 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3812 US"AUTH command used when not advertised");
3815 if (sender_host_authenticated)
3817 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3818 US"already authenticated");
3823 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3824 US"not permitted in mail transaction");
3830 GET_OPTION("acl_smtp_auth");
3832 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3833 &user_msg, &log_msg)) != OK
3836 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3840 /* Find the name of the requested authentication mechanism. */
3843 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
3844 if (!isalnum(c) && c != '-' && c != '_')
3846 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3847 US"invalid character in authentication mechanism name");
3851 /* If not at the end of the line, we must be at white space. Terminate the
3852 name and move the pointer on to any data that may be present. */
3856 *smtp_cmd_data++ = '\0';
3857 Uskip_whitespace(&smtp_cmd_data);
3860 /* Search for an authentication mechanism which is configured for use
3861 as a server and which has been advertised (unless, sigh, allow_auth_
3862 unadvertised is set). */
3866 uschar * smtp_resp, * errmsg;
3868 for (au = auths; au; au = au->drinst.next)
3869 if (strcmpic(s, au->public_name) == 0 && au->server &&
3870 (au->advertised || f.allow_auth_unadvertised))
3875 int rc = smtp_in_auth(au, &smtp_resp, &errmsg);
3877 smtp_printf("%s\r\n", SP_NO_MORE, smtp_resp);
3880 uschar * logmsg = NULL;
3881 #ifndef DISABLE_EVENT
3882 {uschar * save_name = sender_host_authenticated;
3883 sender_host_authenticated = au->drinst.name;
3884 logmsg = event_raise(event_action, US"auth:fail", smtp_resp, NULL);
3885 sender_host_authenticated = save_name;
3889 log_write(0, LOG_MAIN|LOG_REJECT, "%s", logmsg);
3891 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3892 au->drinst.name, host_and_ident(FALSE), errmsg);
3896 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3897 string_sprintf("%s authentication mechanism not supported", s));
3900 break; /* AUTH_CMD */
3902 /* The HELO/EHLO commands are permitted to appear in the middle of a
3903 session as well as at the beginning. They have the effect of a reset in
3904 addition to their other functions. Their absence at the start cannot be
3905 taken to be an error.
3909 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3910 or 502 failure replies MUST be returned as appropriate. The SMTP
3911 server MUST stay in the same state after transmitting these replies
3912 that it was in before the EHLO was received.
3914 Therefore, we do not do the reset until after checking the command for
3915 acceptability. This change was made for Exim release 4.11. Previously
3916 it did the reset first. */
3929 HELO_EHLO: /* Common code for HELO and EHLO */
3930 cmd_list[CL_HELO].is_mail_cmd = FALSE;
3931 cmd_list[CL_EHLO].is_mail_cmd = FALSE;
3933 /* Reject the HELO if its argument was invalid or non-existent. A
3934 successful check causes the argument to be saved in malloc store. */
3936 if (!check_helo(smtp_cmd_data))
3938 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", SP_NO_MORE, hello);
3940 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3941 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3942 *smtp_cmd_argument == 0 ? US"(no argument given)" :
3943 string_printing(smtp_cmd_argument));
3945 if (++synprot_error_count > smtp_max_synprot_errors)
3947 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3948 "syntax or protocol errors (last command was \"%s\", %Y)",
3949 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3958 /* If sender_host_unknown is true, we have got here via the -bs interface,
3959 not called from inetd. Otherwise, we are running an IP connection and the
3960 host address will be set. If the helo name is the primary name of this
3961 host and we haven't done a reverse lookup, force one now. If helo_verify_required
3962 is set, ensure that the HELO name matches the actual host. If helo_verify
3963 is set, do the same check, but softly. */
3965 if (!f.sender_host_unknown)
3967 BOOL old_helo_verified = f.helo_verified;
3968 uschar * p = smtp_cmd_data;
3970 while (*p && !isspace(*p)) { *p = tolower(*p); p++; }
3973 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3974 because otherwise the log can be confusing. */
3976 if ( !sender_host_name
3977 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3978 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
3979 (void)host_name_lookup();
3981 /* Rebuild the fullhost info to include the HELO name (and the real name
3982 if it was looked up.) */
3984 host_build_sender_fullhost(); /* Rebuild */
3985 set_process_info("handling%s incoming connection from %s",
3986 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
3988 /* Verify if configured. This doesn't give much security, but it does
3989 make some people happy to be able to do it. If helo_verify_required is set,
3990 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3991 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3992 now obsolescent, since the verification can now be requested selectively
3995 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
3996 if (fl.helo_verify_required || fl.helo_verify)
3998 BOOL tempfail = !smtp_verify_helo();
3999 if (!f.helo_verified)
4001 if (fl.helo_verify_required)
4003 smtp_printf("%d %s argument does not match calling host\r\n", SP_NO_MORE,
4004 tempfail? 451 : 550, hello);
4005 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4006 tempfail? "temporarily " : "",
4007 hello, sender_helo_name, host_and_ident(FALSE));
4008 f.helo_verified = old_helo_verified;
4009 break; /* End of HELO/EHLO processing */
4011 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4012 "helo_try_verify_hosts\n", hello);
4017 /* For any misc-module having a connection-init routine, call it. */
4019 if (misc_mod_conn_init(sender_helo_name, sender_host_address) != OK)
4021 DEBUG(D_receive) debug_printf("A module conn-init routine failed\n");
4026 /* Apply an ACL check if one is defined; afterwards, recheck
4027 synchronization in case the client started sending in a delay. */
4029 GET_OPTION("acl_smtp_helo");
4031 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4032 &user_msg, &log_msg)) != OK)
4034 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4035 sender_helo_name = NULL;
4036 host_build_sender_fullhost(); /* Rebuild */
4039 #ifndef DISABLE_PIPE_CONNECT
4040 else if (!fl.pipe_connect_acceptable && !check_sync())
4042 else if (!check_sync())
4046 /* Generate an OK reply. The default string includes the ident if present,
4047 and also the IP address if present. Reflecting back the ident is intended
4048 as a deterrent to mail forgers. For maximum efficiency, and also because
4049 some broken systems expect each response to be in a single packet, arrange
4050 that the entire reply is sent in one write(). */
4052 fl.auth_advertised = FALSE;
4053 f.smtp_in_pipelining_advertised = FALSE;
4055 fl.tls_advertised = FALSE;
4057 fl.dsn_advertised = FALSE;
4059 fl.smtputf8_advertised = FALSE;
4062 /* Expand the per-connection message count limit option */
4063 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4065 smtp_code = US"250 "; /* Default response code plus space*/
4068 /* sender_host_name below will be tainted, so save on copy when we hit it */
4069 g = string_get_tainted(24, GET_TAINTED);
4070 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4072 smtp_active_hostname,
4073 sender_ident ? sender_ident : US"",
4074 sender_ident ? US" at " : US"",
4075 sender_host_name ? sender_host_name : sender_helo_name);
4077 if (sender_host_address)
4078 g = string_fmt_append(g, " [%s]", sender_host_address);
4081 /* A user-supplied EHLO greeting may not contain more than one line. Note
4082 that the code returned by smtp_message_code() includes the terminating
4083 whitespace character. */
4089 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4090 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4091 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4093 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4094 "newlines: message truncated: %s", string_printing(s));
4097 g = string_cat(NULL, s);
4100 g = string_catn(g, US"\r\n", 2);
4102 /* If we received EHLO, we must create a multiline response which includes
4103 the functions supported. */
4107 g->s[3] = '-'; /* overwrite the space after the SMTP response code */
4109 /* I'm not entirely happy with this, as an MTA is supposed to check
4110 that it has enough room to accept a message of maximum size before
4111 it sends this. However, there seems little point in not sending it.
4112 The actual size check happens later at MAIL FROM time. By postponing it
4113 till then, VRFY and EXPN can be used after EHLO when space is short. */
4115 if (thismessage_size_limit > 0)
4116 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4117 thismessage_size_limit);
4120 g = string_catn(g, smtp_code, 3);
4121 g = string_catn(g, US"-SIZE\r\n", 7);
4124 #ifndef DISABLE_ESMTP_LIMITS
4125 if ( (smtp_mailcmd_max > 0 || recipients_max_expanded > 0)
4126 && verify_check_host(&limits_advertise_hosts) == OK)
4128 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4129 if (smtp_mailcmd_max > 0)
4130 g = string_fmt_append(g, " MAILMAX=%d", smtp_mailcmd_max);
4131 if (recipients_max_expanded > 0)
4132 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max_expanded);
4133 g = string_catn(g, US"\r\n", 2);
4137 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4138 clean; if it has an 8-bit character in its hand, it just sends it. It
4139 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4140 However, some users want this option simply in order to stop MUAs
4141 mangling messages that contain top-bit-set characters. It is therefore
4142 provided as an option. */
4144 if (accept_8bitmime)
4146 g = string_catn(g, smtp_code, 3);
4147 g = string_catn(g, US"-8BITMIME\r\n", 11);
4150 /* Advertise DSN support if configured to do so. */
4151 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4153 g = string_catn(g, smtp_code, 3);
4154 g = string_catn(g, US"-DSN\r\n", 6);
4155 fl.dsn_advertised = TRUE;
4158 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4159 permitted to issue them; a check is made when any host actually tries. */
4161 GET_OPTION("acl_smtp_etrn");
4164 g = string_catn(g, smtp_code, 3);
4165 g = string_catn(g, US"-ETRN\r\n", 7);
4167 GET_OPTION("acl_smtp_vrfy");
4170 g = string_catn(g, smtp_code, 3);
4171 g = string_catn(g, US"-VRFY\r\n", 7);
4173 GET_OPTION("acl_smtp_expn");
4176 g = string_catn(g, smtp_code, 3);
4177 g = string_catn(g, US"-EXPN\r\n", 7);
4180 /* Exim is quite happy with pipelining, so let the other end know that
4181 it is safe to use it, unless advertising is disabled. */
4183 if ( f.pipelining_enable
4184 && verify_check_host(&pipelining_advertise_hosts) == OK)
4186 g = string_catn(g, smtp_code, 3);
4187 g = string_catn(g, US"-PIPELINING\r\n", 13);
4188 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4189 f.smtp_in_pipelining_advertised = TRUE;
4191 #ifndef DISABLE_PIPE_CONNECT
4192 if (fl.pipe_connect_acceptable)
4194 f.smtp_in_early_pipe_advertised = TRUE;
4195 g = string_catn(g, smtp_code, 3);
4196 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4202 /* If any server authentication mechanisms are configured, advertise
4203 them if the current host is in auth_advertise_hosts. The problem with
4204 advertising always is that some clients then require users to
4205 authenticate (and aren't configurable otherwise) even though it may not
4206 be necessary (e.g. if the host is in host_accept_relay).
4208 RFC 2222 states that SASL mechanism names contain only upper case
4209 letters, so output the names in upper case, though we actually recognize
4210 them in either case in the AUTH command. */
4214 && !sender_host_authenticated
4216 && verify_check_host(&auth_advertise_hosts) == OK
4220 for (auth_instance * au = auths; au; au = au->drinst.next)
4222 au->advertised = FALSE;
4225 DEBUG(D_auth+D_expand) debug_printf_indent(
4226 "Evaluating advertise_condition for %s %s athenticator\n",
4227 au->drinst.name, au->public_name);
4228 if ( !au->advertise_condition
4229 || expand_check_condition(au->advertise_condition,
4230 au->drinst.name, US"authenticator")
4236 g = string_catn(g, smtp_code, 3);
4237 g = string_catn(g, US"-AUTH", 5);
4239 fl.auth_advertised = TRUE;
4241 saveptr = gstring_length(g);
4242 g = string_catn(g, US" ", 1);
4243 g = string_cat(g, au->public_name);
4244 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4245 au->advertised = TRUE;
4250 if (!first) g = string_catn(g, US"\r\n", 2);
4253 /* RFC 3030 CHUNKING */
4255 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4257 g = string_catn(g, smtp_code, 3);
4258 g = string_catn(g, US"-CHUNKING\r\n", 11);
4259 f.chunking_offered = TRUE;
4260 chunking_state = CHUNKING_OFFERED;
4264 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4265 if it has been included in the binary, and the host matches
4266 tls_advertise_hosts. We must *not* advertise if we are already in a
4267 secure connection. */
4269 if (tls_in.active.sock < 0 &&
4270 verify_check_host(&tls_advertise_hosts) != FAIL)
4272 g = string_catn(g, smtp_code, 3);
4273 g = string_catn(g, US"-STARTTLS\r\n", 11);
4274 fl.tls_advertised = TRUE;
4277 #ifdef EXPERIMENTAL_XCLIENT
4278 if (proxy_session || verify_check_host(&hosts_xclient) != FAIL)
4280 g = string_catn(g, smtp_code, 3);
4281 g = xclient_smtp_advertise_str(g);
4284 #ifndef DISABLE_PRDR
4285 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4288 g = string_catn(g, smtp_code, 3);
4289 g = string_catn(g, US"-PRDR\r\n", 7);
4294 if ( accept_8bitmime
4295 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4297 g = string_catn(g, smtp_code, 3);
4298 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4299 fl.smtputf8_advertised = TRUE;
4302 #ifndef DISABLE_WELLKNOWN
4303 if (verify_check_host(&wellknown_advertise_hosts) != FAIL)
4305 g = string_catn(g, smtp_code, 3);
4306 g = string_catn(g, US"-WELLKNOWN\r\n", 12);
4310 /* Finish off the multiline reply with one that is always available. */
4312 g = string_catn(g, smtp_code, 3);
4313 g = string_catn(g, US" HELP\r\n", 7);
4316 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4321 int len = len_string_from_gstring(g, &ehlo_resp);
4323 if (tls_in.active.sock >= 0)
4324 (void) tls_write(NULL, ehlo_resp, len,
4325 # ifndef DISABLE_PIPE_CONNECT
4326 fl.pipe_connect_acceptable && pipeline_connect_sends());
4332 (void) fwrite(ehlo_resp, 1, len, smtp_out);
4334 DEBUG(D_receive) for (const uschar * t, * s = ehlo_resp;
4335 s && (t = Ustrchr(s, '\r'));
4336 s = t + 2) /* \r\n */
4337 debug_printf("%s %.*s\n",
4338 s == g->s ? "SMTP>>" : " ",
4340 fl.helo_seen = TRUE;
4343 /* Reset the protocol and the state, abandoning any previous message. */
4345 (sender_host_address ? protocols : protocols_local)
4347 ? pextend + (sender_host_authenticated ? pauthed : 0)
4349 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4351 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4352 reset_point = smtp_reset(reset_point);
4354 break; /* HELO/EHLO */
4356 #ifndef DISABLE_WELLKNOWN
4359 smtp_mailcmd_count++;
4360 smtp_wellknown_handler();
4364 #ifdef EXPERIMENTAL_XCLIENT
4367 BOOL fatal = fl.helo_seen;
4372 smtp_mailcmd_count++;
4374 if ((errmsg = xclient_smtp_command(smtp_cmd_data, &resp, &fatal)))
4376 done = synprot_error(L_smtp_syntax_error, resp, NULL, errmsg);
4379 smtp_printf("%d %s\r\n", SP_NO_MORE, resp, errmsg);
4380 log_write(0, LOG_MAIN|LOG_REJECT, "rejected XCLIENT from %s: %s",
4381 host_and_ident(FALSE), errmsg);
4385 fl.helo_seen = FALSE; /* Require another EHLO */
4386 smtp_code = string_sprintf("%d", resp);
4388 /*XXX unclear in spec. if this needs to be an ESMTP banner,
4389 nor whether we get the original client's HELO after (or a proxy fake).
4390 We require that we do; the following HELO/EHLO handling will set
4391 sender_helo_name as normal. */
4393 smtp_printf("%s XCLIENT success\r\n", SP_NO_MORE, smtp_code);
4395 break; /* XCLIENT */
4400 /* The MAIL command requires an address as an operand. All we do
4401 here is to parse it for syntactic correctness. The form "<>" is
4402 a special case which converts into an empty string. The start/end
4403 pointers in the original are not used further for this address, as
4404 it is the canonical extracted address which is all that is kept. */
4408 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4410 was_rej_mail = TRUE; /* Reset if accepted */
4411 env_mail_type_t * mail_args; /* Sanity check & validate args */
4414 if ( fl.helo_verify_required
4415 || verify_check_host(&hosts_require_helo) == OK)
4417 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4418 "HELO/EHLO given", host_and_ident(FALSE));
4419 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4420 US"HELO or EHLO required");
4423 else if (smtp_mailcmd_max < 0)
4424 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4428 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4429 US"sender already given");
4433 if (!*smtp_cmd_data)
4435 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4436 US"MAIL must have an address operand");
4440 /* Check to see if the limit for messages per connection would be
4441 exceeded by accepting further messages. */
4443 if (smtp_mailcmd_max > 0 && smtp_mailcmd_count > smtp_mailcmd_max)
4445 smtp_printf("421 too many messages in this connection\r\n", SP_NO_MORE);
4446 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4447 "messages in one connection", host_and_ident(TRUE));
4451 /* Reset for start of message - even if this is going to fail, we
4452 obviously need to throw away any previous data. */
4454 cancel_cutthrough_connection(TRUE, US"MAIL received");
4455 reset_point = smtp_reset(reset_point);
4457 sender_data = recipient_data = NULL;
4459 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4461 if (fl.esmtp) for(;;)
4463 uschar *name, *value, *end;
4464 unsigned long int size;
4465 BOOL arg_error = FALSE;
4467 if (!extract_option(&name, &value)) break;
4469 for (mail_args = env_mail_type_list;
4470 mail_args->value != ENV_MAIL_OPT_NULL;
4473 if (strcmpic(name, mail_args->name) == 0)
4475 if (mail_args->need_value && strcmpic(value, US"") == 0)
4478 switch(mail_args->value)
4480 /* Handle SIZE= by reading the value. We don't do the check till later,
4481 in order to be able to log the sender address on failure. */
4482 case ENV_MAIL_OPT_SIZE:
4483 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4485 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4487 message_size = (int)size;
4493 /* If this session was initiated with EHLO and accept_8bitmime is set,
4494 Exim will have indicated that it supports the BODY=8BITMIME option. In
4495 fact, it does not support this according to the RFCs, in that it does not
4496 take any special action for forwarding messages containing 8-bit
4497 characters. That is why accept_8bitmime is not the default setting, but
4498 some sites want the action that is provided. We recognize both "8BITMIME"
4499 and "7BIT" as body types, but take no action. */
4500 case ENV_MAIL_OPT_BODY:
4501 if (accept_8bitmime) {
4502 if (strcmpic(value, US"8BITMIME") == 0)
4504 else if (strcmpic(value, US"7BIT") == 0)
4509 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4510 US"invalid data for BODY");
4513 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4519 /* Handle the two DSN options, but only if configured to do so (which
4520 will have caused "DSN" to be given in the EHLO response). The code itself
4521 is included only if configured in at build time. */
4523 case ENV_MAIL_OPT_RET:
4524 if (fl.dsn_advertised)
4526 /* Check if RET has already been set */
4529 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4530 US"RET can be specified once only");
4533 dsn_ret = strcmpic(value, US"HDRS") == 0
4535 : strcmpic(value, US"FULL") == 0
4538 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4539 /* Check for invalid invalid value, and exit with error */
4542 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4543 US"Value for RET is invalid");
4548 case ENV_MAIL_OPT_ENVID:
4549 if (fl.dsn_advertised)
4551 /* Check if the dsn envid has been already set */
4554 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4555 US"ENVID can be specified once only");
4558 dsn_envid = string_copy(value);
4559 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4563 /* Handle the AUTH extension. If the value given is not "<>" and either
4564 the ACL says "yes" or there is no ACL but the sending host is
4565 authenticated, we set it up as the authenticated sender. However, if the
4566 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4567 the condition is met. The value of AUTH is an xtext, which means that +,
4568 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4570 case ENV_MAIL_OPT_AUTH:
4571 if (Ustrcmp(value, "<>") != 0)
4576 if (xtextdecode(value, &authenticated_sender) < 0)
4578 /* Put back terminator overrides for error message */
4581 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4582 US"invalid data for AUTH");
4585 GET_OPTION("acl_smtp_mailauth");
4586 if (!acl_smtp_mailauth)
4588 ignore_msg = US"client not authenticated";
4589 rc = sender_host_authenticated ? OK : FAIL;
4593 ignore_msg = US"rejected by ACL";
4594 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4595 &user_msg, &log_msg);
4601 if (authenticated_by == NULL ||
4602 authenticated_by->mail_auth_condition == NULL ||
4603 expand_check_condition(authenticated_by->mail_auth_condition,
4604 authenticated_by->drinst.name, US"authenticator"))
4605 break; /* Accept the AUTH */
4607 ignore_msg = US"server_mail_auth_condition failed";
4608 if (authenticated_id != NULL)
4609 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4610 ignore_msg, authenticated_id);
4615 authenticated_sender = NULL;
4616 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4617 value, host_and_ident(TRUE), ignore_msg);
4620 /* Should only get DEFER or ERROR here. Put back terminator
4621 overrides for error message */
4626 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4633 #ifndef DISABLE_PRDR
4634 case ENV_MAIL_OPT_PRDR:
4636 prdr_requested = TRUE;
4641 case ENV_MAIL_OPT_UTF8:
4642 if (!fl.smtputf8_advertised)
4644 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4645 US"SMTPUTF8 used when not advertised");
4649 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4650 message_smtputf8 = allow_utf8_domains = TRUE;
4651 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4653 int old_pool = store_pool;
4654 store_pool = POOL_PERM;
4655 received_protocol = string_sprintf("utf8%s", received_protocol);
4656 store_pool = old_pool;
4661 /* No valid option. Stick back the terminator characters and break
4662 the loop. Do the name-terminator second as extract_option sets
4663 value==name when it found no equal-sign.
4664 An error for a malformed address will occur. */
4665 case ENV_MAIL_OPT_NULL:
4673 /* Break out of for loop if switch() had bad argument or
4674 when start of the email address is reached */
4675 if (arg_error) break;
4678 /* If we have passed the threshold for rate limiting, apply the current
4679 delay, and update it for next time, provided this is a limited host. */
4681 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4682 verify_check_host(&smtp_ratelimit_hosts) == OK)
4684 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4685 smtp_delay_mail/1000.0);
4686 millisleep((int)smtp_delay_mail);
4687 smtp_delay_mail *= smtp_rlm_factor;
4688 if (smtp_delay_mail > (double)smtp_rlm_limit)
4689 smtp_delay_mail = (double)smtp_rlm_limit;
4692 /* Now extract the address, first applying any SMTP-time rewriting. The
4693 TRUE flag allows "<>" as a sender address. */
4695 raw_sender = rewrite_existflags & rewrite_smtp
4696 /* deconst ok as smtp_cmd_data was not const */
4697 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4698 global_rewrite_rules)
4702 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4707 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4711 sender_address = raw_sender;
4713 /* If there is a configured size limit for mail, check that this message
4714 doesn't exceed it. The check is postponed to this point so that the sender
4717 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4719 smtp_printf("552 Message size exceeds maximum permitted\r\n", SP_NO_MORE);
4720 log_write(L_size_reject,
4721 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4722 "message too big: size%s=%d max=%d",
4724 host_and_ident(TRUE),
4725 (message_size == INT_MAX)? ">" : "",
4727 thismessage_size_limit);
4728 sender_address = NULL;
4732 /* Check there is enough space on the disk unless configured not to.
4733 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4734 plus the current message - i.e. we accept the message only if it won't
4735 reduce the space below the threshold. Add 5000 to the size to allow for
4736 overheads such as the Received: line and storing of recipients, etc.
4737 By putting the check here, even when SIZE is not given, it allow VRFY
4738 and EXPN etc. to be used when space is short. */
4740 if (!receive_check_fs(
4741 smtp_check_spool_space && message_size >= 0
4742 ? message_size + 5000 : 0))
4744 smtp_printf("452 Space shortage, please try later\r\n", SP_NO_MORE);
4745 sender_address = NULL;
4749 /* If sender_address is unqualified, reject it, unless this is a locally
4750 generated message, or the sending host or net is permitted to send
4751 unqualified addresses - typically local machines behaving as MUAs -
4752 in which case just qualify the address. The flag is set above at the start
4753 of the SMTP connection. */
4755 if (!sender_domain && *sender_address)
4756 if (f.allow_unqualified_sender)
4758 sender_domain = Ustrlen(sender_address) + 1;
4759 /* deconst ok as sender_address was not const */
4760 sender_address = US rewrite_address_qualify(sender_address, FALSE);
4761 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4766 smtp_printf("501 %s: sender address must contain a domain\r\n", SP_NO_MORE,
4768 log_write(L_smtp_syntax_error,
4769 LOG_MAIN|LOG_REJECT,
4770 "unqualified sender rejected: <%s> %s%s",
4772 host_and_ident(TRUE),
4774 sender_address = NULL;
4778 /* Apply an ACL check if one is defined, before responding. Afterwards,
4779 when pipelining is not advertised, do another sync check in case the ACL
4780 delayed and the client started sending in the meantime. */
4782 GET_OPTION("acl_smtp_mail");
4785 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4786 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4792 if (rc == OK || rc == DISCARD)
4794 BOOL more = pipeline_response();
4797 smtp_printf("%s%s%s", more, US"250 OK",
4798 #ifndef DISABLE_PRDR
4799 prdr_requested ? US", PRDR Requested" : US"",
4806 #ifndef DISABLE_PRDR
4808 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4810 smtp_user_msg(US"250", user_msg);
4812 smtp_delay_rcpt = smtp_rlr_base;
4813 f.recipients_discarded = (rc == DISCARD);
4814 was_rej_mail = FALSE;
4818 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4819 sender_address = NULL;
4824 /* The RCPT command requires an address as an operand. There may be any
4825 number of RCPT commands, specifying multiple recipients. We build them all
4826 into a data structure. The start/end values given by parse_extract_address
4827 are not used, as we keep only the extracted address. */
4831 /* We got really to many recipients. A check against configured
4832 limits is done later */
4833 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
4834 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
4836 was_rcpt = fl.rcpt_in_progress = TRUE;
4838 /* There must be a sender address; if the sender was rejected and
4839 pipelining was advertised, we assume the client was pipelining, and do not
4840 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4841 get the same treatment. */
4843 if (!sender_address)
4845 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4847 smtp_printf("503 sender not yet given\r\n", SP_NO_MORE);
4848 was_rej_mail = TRUE;
4852 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4853 US"sender not yet given");
4854 was_rcpt = FALSE; /* Not a valid RCPT */
4860 /* Check for an operand */
4862 if (!smtp_cmd_data[0])
4864 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4865 US"RCPT must have an address operand");
4870 /* Set the DSN flags orcpt and dsn_flags from the session*/
4874 if (fl.esmtp) for(;;)
4876 uschar *name, *value;
4878 if (!extract_option(&name, &value))
4881 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4883 /* Check whether orcpt has been already set */
4886 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4887 US"ORCPT can be specified once only");
4890 orcpt = string_copy(value);
4891 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4894 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4896 /* Check if the notify flags have been already set */
4899 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4900 US"NOTIFY can be specified once only");
4903 if (strcmpic(value, US"NEVER") == 0)
4904 dsn_flags |= rf_notify_never;
4911 while (*pp != 0 && *pp != ',') pp++;
4912 if (*pp == ',') *pp++ = 0;
4913 if (strcmpic(p, US"SUCCESS") == 0)
4915 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4916 dsn_flags |= rf_notify_success;
4918 else if (strcmpic(p, US"FAILURE") == 0)
4920 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4921 dsn_flags |= rf_notify_failure;
4923 else if (strcmpic(p, US"DELAY") == 0)
4925 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4926 dsn_flags |= rf_notify_delay;
4930 /* Catch any strange values */
4931 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4932 US"Invalid value for NOTIFY parameter");
4937 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
4941 /* Unknown option. Stick back the terminator characters and break
4942 the loop. An error for a malformed address will occur. */
4946 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4953 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4954 as a recipient address */
4956 recipient = rewrite_existflags & rewrite_smtp
4957 /* deconst ok as smtp_cmd_data was not const */
4958 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4959 global_rewrite_rules)
4962 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4963 &recipient_domain, FALSE)))
4965 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4970 /* If the recipient address is unqualified, reject it, unless this is a
4971 locally generated message. However, unqualified addresses are permitted
4972 from a configured list of hosts and nets - typically when behaving as
4973 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4974 really. The flag is set at the start of the SMTP connection.
4976 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4977 assumed this meant "reserved local part", but the revision of RFC 821 and
4978 friends now makes it absolutely clear that it means *mailbox*. Consequently
4979 we must always qualify this address, regardless. */
4981 if (!recipient_domain)
4982 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4989 /* Check maximum allowed */
4991 if ( rcpt_count+1 < 0
4992 || rcpt_count > recipients_max_expanded && recipients_max_expanded > 0)
4994 if (recipients_max_reject)
4997 smtp_printf("552 too many recipients\r\n", SP_NO_MORE);
4999 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5000 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5005 smtp_printf("452 too many recipients\r\n", SP_NO_MORE);
5007 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5008 "temporarily rejected: sender=<%s> %s", sender_address,
5009 host_and_ident(TRUE));
5016 /* If we have passed the threshold for rate limiting, apply the current
5017 delay, and update it for next time, provided this is a limited host. */
5019 if (rcpt_count > smtp_rlr_threshold &&
5020 verify_check_host(&smtp_ratelimit_hosts) == OK)
5022 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5023 smtp_delay_rcpt/1000.0);
5024 millisleep((int)smtp_delay_rcpt);
5025 smtp_delay_rcpt *= smtp_rlr_factor;
5026 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5027 smtp_delay_rcpt = (double)smtp_rlr_limit;
5030 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5031 for them. Otherwise, check the access control list for this recipient. As
5032 there may be a delay in this, re-check for a synchronization error
5033 afterwards, unless pipelining was advertised. */
5035 if (f.recipients_discarded)
5039 GET_OPTION("acl_smtp_rcpt");
5040 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5042 && !f.smtp_in_pipelining_advertised && !check_sync())
5046 /* The ACL was happy */
5050 BOOL more = pipeline_response();
5053 smtp_user_msg(US"250", user_msg);
5055 smtp_printf("250 Accepted\r\n", more);
5056 receive_add_recipient(recipient, -1);
5058 /* Set the dsn flags in the recipients_list */
5059 recipients_list[recipients_count-1].orcpt = orcpt;
5060 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5062 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5063 recipients_list[recipients_count-1].orcpt,
5064 recipients_list[recipients_count-1].dsn_flags); */
5067 /* The recipient was discarded */
5069 else if (rc == DISCARD)
5072 smtp_user_msg(US"250", user_msg);
5074 smtp_printf("250 Accepted\r\n", SP_NO_MORE);
5077 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5078 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5079 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5080 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5081 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5084 /* Either the ACL failed the address, or it was deferred. */
5088 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5089 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5094 /* The DATA command is legal only if it follows successful MAIL FROM
5095 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5096 not counted as a protocol error if it follows RCPT (which must have been
5097 rejected if there are no recipients.) This function is complete when a
5098 valid DATA command is encountered.
5100 Note concerning the code used: RFC 2821 says this:
5102 - If there was no MAIL, or no RCPT, command, or all such commands
5103 were rejected, the server MAY return a "command out of sequence"
5104 (503) or "no valid recipients" (554) reply in response to the
5107 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5108 because it is the same whether pipelining is in use or not.
5110 If all the RCPT commands that precede DATA provoked the same error message
5111 (often indicating some kind of system error), it is helpful to include it
5112 with the DATA rejection (an idea suggested by Tony Finch). */
5119 if (chunking_state != CHUNKING_OFFERED)
5121 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5122 US"BDAT command used when CHUNKING not advertised");
5126 /* grab size, endmarker */
5128 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5130 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5131 US"missing size for BDAT command");
5134 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5135 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5136 chunking_data_left = chunking_datasize;
5137 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5138 (int)chunking_state, chunking_data_left);
5140 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
5149 f.bdat_readers_wanted = FALSE;
5151 DATA_BDAT: /* Common code for DATA and BDAT */
5152 #ifndef DISABLE_PIPE_CONNECT
5153 fl.pipe_connect_acceptable = FALSE;
5155 if (!discarded && recipients_count <= 0)
5157 if (fl.rcpt_smtp_response_same && rcpt_smtp_response)
5159 uschar *code = US"503";
5160 int len = Ustrlen(rcpt_smtp_response);
5161 smtp_respond(code, 3, SR_NOT_FINAL, US"All RCPT commands were rejected with "
5163 /* Responses from smtp_printf() will have \r\n on the end */
5164 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5165 rcpt_smtp_response[len-2] = 0;
5166 smtp_respond(code, 3, SR_NOT_FINAL, rcpt_smtp_response);
5168 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5169 smtp_printf("503 Valid RCPT command must precede %s\r\n", SP_NO_MORE,
5170 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5172 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5173 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5174 ? US"valid RCPT command must precede DATA"
5175 : US"valid RCPT command must precede BDAT");
5177 if (chunking_state > CHUNKING_OFFERED)
5179 bdat_push_receive_functions();
5185 if (toomany && recipients_max_reject)
5187 sender_address = NULL; /* This will allow a new MAIL without RSET */
5188 sender_address_unrewritten = NULL;
5189 smtp_printf("554 Too many recipients\r\n", SP_NO_MORE);
5191 if (chunking_state > CHUNKING_OFFERED)
5193 bdat_push_receive_functions();
5199 if (chunking_state > CHUNKING_OFFERED)
5200 rc = OK; /* There is no predata ACL or go-ahead output for BDAT */
5203 /* If there is a predata-ACL, re-check the synchronization afterwards,
5204 since the ACL may have delayed. To handle cutthrough delivery enforce a
5205 dummy call to get the DATA command sent. */
5207 GET_OPTION("acl_smtp_predata");
5208 if (!acl_smtp_predata && cutthrough.cctx.sock < 0)
5212 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5213 f.enable_dollar_recipients = TRUE;
5214 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5216 f.enable_dollar_recipients = FALSE;
5217 if (rc == OK && !check_sync())
5221 { /* Either the ACL failed the address, or it was deferred. */
5222 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5228 smtp_user_msg(US"354", user_msg);
5231 "354 Enter message, ending with \".\" on a line by itself\r\n", SP_NO_MORE);
5234 if (f.bdat_readers_wanted)
5235 bdat_push_receive_functions();
5238 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5239 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5240 US &on, sizeof(on));
5243 message_ended = END_NOTENDED; /* Indicate in middle of data */
5254 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5255 &start, &end, &recipient_domain, FALSE)))
5257 smtp_printf("501 %s\r\n", SP_NO_MORE, errmess);
5261 if (!recipient_domain)
5262 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5266 GET_OPTION("acl_smtp_vrfy");
5267 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5268 &user_msg, &log_msg)) != OK)
5269 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5273 address_item * addr = deliver_make_addr(address, FALSE);
5275 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5276 -1, -1, NULL, NULL, NULL))
5279 s = string_sprintf("250 <%s> is deliverable", address);
5283 s = (addr->user_message != NULL)?
5284 string_sprintf("451 <%s> %s", address, addr->user_message) :
5285 string_sprintf("451 Cannot resolve <%s> at this time", address);
5289 s = (addr->user_message != NULL)?
5290 string_sprintf("550 <%s> %s", address, addr->user_message) :
5291 string_sprintf("550 <%s> is not deliverable", address);
5292 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5293 smtp_cmd_argument, host_and_ident(TRUE));
5297 smtp_printf("%s\r\n", SP_NO_MORE, s);
5305 GET_OPTION("acl_smtp_expn");
5306 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5308 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5311 BOOL save_log_testing_mode = f.log_testing_mode;
5312 f.address_test_mode = f.log_testing_mode = TRUE;
5313 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5314 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5316 f.address_test_mode = FALSE;
5317 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5326 if (!fl.tls_advertised)
5328 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5329 US"STARTTLS command used when not advertised");
5333 /* Apply an ACL check if one is defined */
5335 GET_OPTION("acl_smtp_starttls");
5336 if ( acl_smtp_starttls
5337 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5338 &user_msg, &log_msg)) != OK
5341 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5345 /* RFC 2487 is not clear on when this command may be sent, though it
5346 does state that all information previously obtained from the client
5347 must be discarded if a TLS session is started. It seems reasonable to
5348 do an implied RSET when STARTTLS is received. */
5350 incomplete_transaction_log(US"STARTTLS");
5351 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5352 reset_point = smtp_reset(reset_point);
5354 cmd_list[CL_STLS].is_mail_cmd = FALSE;
5356 /* There's an attack where more data is read in past the STARTTLS command
5357 before TLS is negotiated, then assumed to be part of the secure session
5358 when used afterwards; we use segregated input buffers, so are not
5359 vulnerable, but we want to note when it happens and, for sheer paranoia,
5360 ensure that the buffer is "wiped".
5361 Pipelining sync checks will normally have protected us too, unless disabled
5362 by configuration. */
5367 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5368 if (tls_in.active.sock < 0)
5369 smtp_inend = smtp_inptr = smtp_inbuffer;
5370 /* and if TLS is already active, tls_server_start() should fail */
5373 /* There is nothing we value in the input buffer and if TLS is successfully
5374 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5375 fresh content into it. The buffer contains arbitrary content from an
5376 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5377 It seems safest to just wipe away the content rather than leave it as a
5378 target to jump to. */
5380 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5382 /* Attempt to start up a TLS session, and if successful, discard all
5383 knowledge that was obtained previously. At least, that's what the RFC says,
5384 and that's what happens by default. However, in order to work round YAEB,
5385 there is an option to remember the esmtp state. Sigh.
5387 We must allow for an extra EHLO command and an extra AUTH command after
5388 STARTTLS that don't add to the nonmail command count. */
5391 if ((rc = tls_server_start(&s)) == OK)
5393 if (!tls_remember_esmtp)
5394 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5395 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
5396 cmd_list[CL_AUTH].is_mail_cmd = TRUE;
5397 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
5398 if (sender_helo_name)
5400 sender_helo_name = NULL;
5401 host_build_sender_fullhost(); /* Rebuild */
5402 set_process_info("handling incoming TLS connection from %s",
5403 host_and_ident(FALSE));
5406 (sender_host_address ? protocols : protocols_local)
5408 ? pextend + (sender_host_authenticated ? pauthed : 0)
5410 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5413 sender_host_auth_pubname = sender_host_authenticated = NULL;
5414 authenticated_id = NULL;
5415 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5416 DEBUG(D_tls) debug_printf("TLS active\n");
5417 break; /* Successful STARTTLS */
5420 (void) smtp_log_tls_fail(s);
5422 /* Some local configuration problem was discovered before actually trying
5423 to do a TLS handshake; give a temporary error. */
5427 smtp_printf("454 TLS currently unavailable\r\n", SP_NO_MORE);
5431 /* Hard failure. Reject everything except QUIT or closed connection. One
5432 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5433 set, but we must still reject all incoming commands. Another is a handshake
5434 failure - and there may some encrypted data still in the pipe to us, which we
5435 see as garbage commands. */
5437 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5438 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5441 log_close_event(US"by EOF");
5442 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5446 /* It is perhaps arguable as to which exit ACL should be called here,
5447 but as it is probably a situation that almost never arises, it
5448 probably doesn't matter. We choose to call the real QUIT ACL, which in
5449 some sense is perhaps "right". */
5452 f.smtp_in_quit = TRUE;
5454 GET_OPTION("acl_smtp_quit");
5456 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5457 &log_msg)) == ERROR))
5458 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5461 smtp_respond(US"221", 3, SR_FINAL, user_msg);
5463 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
5464 log_close_event(US"by QUIT");
5469 smtp_printf("554 Security failure\r\n", SP_NO_MORE);
5472 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5477 /* The ACL for QUIT is provided for gathering statistical information or
5478 similar; it does not affect the response code, but it can supply a custom
5482 smtp_quit_handler(&user_msg, &log_msg);
5488 smtp_rset_handler();
5489 cancel_cutthrough_connection(TRUE, US"RSET received");
5490 reset_point = smtp_reset(reset_point);
5497 smtp_printf("250 OK\r\n", SP_NO_MORE);
5501 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5502 used, a check will be done for permitted hosts. Show STARTTLS only if not
5503 already in a TLS session and if it would be advertised in the EHLO
5508 smtp_printf("214-Commands supported:\r\n214", SP_MORE);
5509 smtp_printf(" AUTH", SP_MORE);
5511 if (tls_in.active.sock < 0 &&
5512 verify_check_host(&tls_advertise_hosts) != FAIL)
5513 smtp_printf(" STARTTLS", SP_MORE);
5515 smtp_printf(" HELO EHLO MAIL RCPT DATA BDAT", SP_MORE);
5516 smtp_printf(" NOOP QUIT RSET HELP", SP_MORE);
5517 if (acl_smtp_etrn) smtp_printf(" ETRN", SP_MORE);
5518 if (acl_smtp_expn) smtp_printf(" EXPN", SP_MORE);
5519 if (acl_smtp_vrfy) smtp_printf(" VRFY", SP_MORE);
5520 #ifndef DISABLE_WELLKNOWN
5521 if (verify_check_host(&wellknown_advertise_hosts) != FAIL)
5522 smtp_printf(" WELLKNOWN", SP_MORE);
5524 #ifdef EXPERIMENTAL_XCLIENT
5525 if (proxy_session || verify_check_host(&hosts_xclient) != FAIL)
5526 smtp_printf(" XCLIENT", SP_MORE);
5528 smtp_printf("\r\n", SP_NO_MORE);
5533 incomplete_transaction_log(US"connection lost");
5534 smtp_notquit_exit(US"connection-lost", US"421",
5535 US"%s lost input connection", smtp_active_hostname);
5537 /* Don't log by default unless in the middle of a message, as some mailers
5538 just drop the call rather than sending QUIT, and it clutters up the logs.
5541 if (sender_address || recipients_count > 0)
5542 log_write(L_lost_incoming_connection, LOG_MAIN,
5543 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5544 f.sender_host_unknown ? "EOF" : "disconnection",
5545 f.tcp_in_fastopen_logged
5548 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5550 host_and_ident(FALSE), smtp_read_error,
5551 string_timesince(&smtp_connection_start)
5555 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5556 smtp_get_connection_info(),
5557 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5559 string_timesince(&smtp_connection_start)
5570 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5571 US"ETRN is not permitted inside a transaction");
5575 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5576 host_and_ident(FALSE));
5578 GET_OPTION("acl_smtp_etrn");
5579 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5580 &user_msg, &log_msg)) != OK)
5582 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5586 /* Compute the serialization key for this command. */
5588 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5590 /* If a command has been specified for running as a result of ETRN, we
5591 permit any argument to ETRN. If not, only the # standard form is permitted,
5592 since that is strictly the only kind of ETRN that can be implemented
5593 according to the RFC. */
5595 GET_OPTION("smtp_etrn_command");
5596 if (smtp_etrn_command)
5600 etrn_command = smtp_etrn_command;
5601 deliver_domain = smtp_cmd_data;
5602 rc = transport_set_up_command(&argv, smtp_etrn_command, TSUC_EXPAND_ARGS, 0, NULL,
5603 US"ETRN processing", &error);
5604 deliver_domain = NULL;
5607 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5609 smtp_printf("458 Internal failure\r\n", SP_NO_MORE);
5614 /* Else set up to call Exim with the -R option. */
5618 if (*smtp_cmd_data++ != '#')
5620 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5621 US"argument must begin with #");
5624 etrn_command = US"exim -R";
5625 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5626 *queue_name ? 4 : 2,
5627 US"-R", smtp_cmd_data,
5628 US"-MCG", queue_name);
5631 /* If we are host-testing, don't actually do anything. */
5637 debug_printf("ETRN command is: %s\n", etrn_command);
5638 debug_printf("ETRN command execution skipped\n");
5640 if (user_msg == NULL) smtp_printf("250 OK\r\n", SP_NO_MORE);
5641 else smtp_user_msg(US"250", user_msg);
5646 /* If ETRN queue runs are to be serialized, check the database to
5647 ensure one isn't already running. */
5649 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5651 smtp_printf("458 Already processing %s\r\n", SP_NO_MORE, smtp_cmd_data);
5655 /* Fork a child process and run the command. We don't want to have to
5656 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5657 forking. It should be set that way anyway for external incoming SMTP,
5658 but we save and restore to be tidy. If serialization is required, we
5659 actually run the command in yet another process, so we can wait for it
5660 to complete and then remove the serialization lock. */
5662 oldsignal = signal(SIGCHLD, SIG_IGN);
5664 if ((pid = exim_fork(US"etrn-command")) == 0)
5666 smtp_input = FALSE; /* This process is not associated with the */
5667 (void)fclose(smtp_in); /* SMTP call any more. */
5668 (void)fclose(smtp_out);
5670 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5672 /* If not serializing, do the exec right away. Otherwise, fork down
5673 into another process. */
5675 if ( !smtp_etrn_serialize
5676 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5678 DEBUG(D_exec) debug_print_argv(argv);
5679 exim_nullstd(); /* Ensure std{in,out,err} exist */
5680 /* argv[0] should be untainted, from child_exec_exim() */
5681 execv(CS argv[0], (char *const *)argv);
5682 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5683 etrn_command, strerror(errno));
5684 _exit(EXIT_FAILURE); /* paranoia */
5687 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5688 is, we are in the first subprocess, after forking again. All we can do
5689 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5690 complete, before removing the serialization. */
5693 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5694 "failed: %s", strerror(errno));
5698 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5700 (void)wait(&status);
5701 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5705 enq_end(etrn_serialize_key);
5706 exim_underbar_exit(EXIT_SUCCESS);
5709 /* Back in the top level SMTP process. Check that we started a subprocess
5710 and restore the signal state. */
5714 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5716 smtp_printf("458 Unable to fork process\r\n", SP_NO_MORE);
5717 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5721 smtp_printf("250 OK\r\n", SP_NO_MORE);
5723 smtp_user_msg(US"250", user_msg);
5725 signal(SIGCHLD, oldsignal);
5730 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5731 US"unexpected argument data");
5735 /* This currently happens only for NULLs, but could be extended. */
5738 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5739 US"NUL character(s) present (shown as '?')");
5740 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5748 unsigned nchars = 150;
5749 uschar * buf = receive_getbuf(&nchars); /* destructive read */
5751 incomplete_transaction_log(US"sync failure");
5752 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5753 "(next input sent too soon: pipelining was%s advertised): "
5754 "rejected \"%s\" %s next input=\"%s\" (%u bytes)",
5755 f.smtp_in_pipelining_advertised ? "" : " not",
5756 smtp_cmd_buffer, host_and_ident(TRUE),
5757 string_printing(buf), nchars);
5758 smtp_notquit_exit(US"synchronization-error", US"554",
5759 US"SMTP synchronization error");
5760 done = 1; /* Pretend eof - drops connection */
5765 case TOO_MANY_NONMAIL_CMD:
5766 s = smtp_cmd_buffer;
5768 incomplete_transaction_log(US"too many non-mail commands");
5769 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5770 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5771 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5772 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5773 done = 1; /* Pretend eof - drops connection */
5776 #ifdef SUPPORT_PROXY
5777 case PROXY_FAIL_IGNORE_CMD:
5778 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", SP_NO_MORE);
5783 if (unknown_command_count++ >= smtp_max_unknown_commands)
5785 log_write(L_smtp_syntax_error, LOG_MAIN,
5786 "SMTP syntax error in \"%s\" %s %s",
5787 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5788 US"unrecognized command");
5789 incomplete_transaction_log(US"unrecognized command");
5790 smtp_notquit_exit(US"bad-commands", US"500",
5791 US"Too many unrecognized commands");
5793 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5794 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5795 string_printing(smtp_cmd_buffer));
5798 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5799 US"unrecognized command");
5803 /* This label is used by goto's inside loops that want to break out to
5804 the end of the command-processing loop. */
5807 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5808 last_was_rcpt = was_rcpt; /* protocol error handling */
5811 return done - 2; /* Convert yield values */
5817 authres_smtpauth(gstring * g)
5819 if (!sender_host_authenticated)
5822 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5824 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
5825 g = authenticated_id
5826 ? string_append(g, 2, US") x509.auth=", authenticated_id)
5827 : string_cat(g, US") reason=x509.auth");
5829 g = authenticated_id
5830 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
5831 : string_cat(g, US", no id saved)");
5833 if (authenticated_sender)
5834 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5842 /* End of smtp_in.c */