1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) The Exim Maintainers 2020 - 2023 */
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=%lu", 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;
1685 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
1686 spf_result_guessed = FALSE;
1688 #ifndef DISABLE_DKIM
1689 dkim_cur_signer = dkim_signers =
1690 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
1691 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
1692 f.dkim_disable_verify = FALSE;
1693 dkim_collect_input = 0;
1694 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
1695 dkim_key_length = 0;
1697 #ifdef SUPPORT_DMARC
1698 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
1699 dmarc_domain_policy = dmarc_status = dmarc_status_text =
1700 dmarc_used_domain = NULL;
1702 #ifdef EXPERIMENTAL_ARC
1703 arc_state = arc_state_reason = NULL;
1704 arc_received_instance = 0;
1708 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
1709 #ifndef DISABLE_PRDR
1710 prdr_requested = FALSE;
1713 message_smtputf8 = FALSE;
1715 #ifdef WITH_CONTENT_SCAN
1718 body_linecount = body_zerocount = 0;
1720 lookup_value = NULL; /* Can be set by ACL */
1721 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1722 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1723 /* Note that ratelimiters_conn persists across resets. */
1725 /* Reset message ACL variables */
1729 /* Warning log messages are saved in malloc store. They are saved to avoid
1730 repetition in the same message, but it seems right to repeat them for different
1733 while (acl_warn_logged)
1735 string_item *this = acl_warn_logged;
1736 acl_warn_logged = acl_warn_logged->next;
1741 store_reset(reset_point);
1744 return store_mark();
1751 /*************************************************
1752 * Initialize for incoming batched SMTP message *
1753 *************************************************/
1755 /* This function is called from smtp_setup_msg() in the case when
1756 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1757 of messages in one file with SMTP commands between them. All errors must be
1758 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1759 relevant. After an error on a sender, or an invalid recipient, the remainder
1760 of the message is skipped. The value of received_protocol is already set.
1763 Returns: > 0 message successfully started (reached DATA)
1764 = 0 QUIT read or end of file reached
1765 < 0 should not occur
1769 smtp_setup_batch_msg(void)
1772 rmark reset_point = store_mark();
1774 /* Save the line count at the start of each transaction - single commands
1775 like HELO and RSET count as whole transactions. */
1777 bsmtp_transaction_linecount = receive_linecount;
1779 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1781 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
1782 reset_point = smtp_reset(reset_point); /* Reset for start of message */
1784 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1785 value. The values are 2 larger than the required yield of the function. */
1790 uschar *recipient = NULL;
1791 int start, end, sender_domain, recipient_domain;
1793 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1795 /* The HELO/EHLO commands set sender_address_helo if they have
1796 valid data; otherwise they are ignored, except that they do
1797 a reset of the state. */
1802 check_helo(smtp_cmd_data);
1806 cancel_cutthrough_connection(TRUE, US"RSET received");
1807 reset_point = smtp_reset(reset_point);
1808 bsmtp_transaction_linecount = receive_linecount;
1811 /* The MAIL FROM command requires an address as an operand. All we
1812 do here is to parse it for syntactic correctness. The form "<>" is
1813 a special case which converts into an empty string. The start/end
1814 pointers in the original are not used further for this address, as
1815 it is the canonical extracted address which is all that is kept. */
1818 smtp_mailcmd_count++; /* Count for no-mail log */
1820 /* The function moan_smtp_batch() does not return. */
1821 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1823 if (smtp_cmd_data[0] == 0)
1824 /* The function moan_smtp_batch() does not return. */
1825 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1827 /* Reset to start of message */
1829 cancel_cutthrough_connection(TRUE, US"MAIL received");
1830 reset_point = smtp_reset(reset_point);
1832 /* Apply SMTP rewrite */
1834 raw_sender = rewrite_existflags & rewrite_smtp
1835 /* deconst ok as smtp_cmd_data was not const */
1836 ? US rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL,
1837 FALSE, US"", global_rewrite_rules)
1840 /* Extract the address; the TRUE flag allows <> as valid */
1843 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1847 /* The function moan_smtp_batch() does not return. */
1848 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1850 sender_address = string_copy(raw_sender);
1852 /* Qualify unqualified sender addresses if permitted to do so. */
1855 && sender_address[0] != 0 && sender_address[0] != '@')
1856 if (f.allow_unqualified_sender)
1858 /* deconst ok as sender_address was not const */
1859 sender_address = US rewrite_address_qualify(sender_address, FALSE);
1860 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1861 "and rewritten\n", raw_sender);
1863 /* The function moan_smtp_batch() does not return. */
1865 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1870 /* The RCPT TO command requires an address as an operand. All we do
1871 here is to parse it for syntactic correctness. There may be any number
1872 of RCPT TO commands, specifying multiple senders. We build them all into
1873 a data structure that is in argc/argv format. The start/end values
1874 given by parse_extract_address are not used, as we keep only the
1875 extracted address. */
1878 if (!sender_address)
1879 /* The function moan_smtp_batch() does not return. */
1880 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1882 if (smtp_cmd_data[0] == 0)
1883 /* The function moan_smtp_batch() does not return. */
1884 moan_smtp_batch(smtp_cmd_buffer,
1885 "501 RCPT TO must have an address operand");
1887 /* Check maximum number allowed */
1889 if ( recipients_max_expanded > 0
1890 && recipients_count + 1 > recipients_max_expanded)
1891 /* The function moan_smtp_batch() does not return. */
1892 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1893 recipients_max_reject ? "552": "452");
1895 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1896 recipient address */
1898 recipient = rewrite_existflags & rewrite_smtp
1899 /* deconst ok as smtp_cmd_data was not const */
1900 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1901 global_rewrite_rules)
1904 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1905 &recipient_domain, FALSE);
1908 /* The function moan_smtp_batch() does not return. */
1909 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1911 /* If the recipient address is unqualified, qualify it if permitted. Then
1912 add it to the list of recipients. */
1914 if (!recipient_domain)
1915 if (f.allow_unqualified_recipient)
1917 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1919 /* deconst ok as recipient was not const */
1920 recipient = US rewrite_address_qualify(recipient, TRUE);
1922 /* The function moan_smtp_batch() does not return. */
1924 moan_smtp_batch(smtp_cmd_buffer,
1925 "501 recipient address must contain a domain");
1927 receive_add_recipient(recipient, -1);
1931 /* The DATA command is legal only if it follows successful MAIL FROM
1932 and RCPT TO commands. This function is complete when a valid DATA
1933 command is encountered. */
1936 if (!sender_address || recipients_count <= 0)
1937 /* The function moan_smtp_batch() does not return. */
1938 if (!sender_address)
1939 moan_smtp_batch(smtp_cmd_buffer,
1940 "503 MAIL FROM:<sender> command must precede DATA");
1942 moan_smtp_batch(smtp_cmd_buffer,
1943 "503 RCPT TO:<recipient> must precede DATA");
1946 done = 3; /* DATA successfully achieved */
1947 message_ended = END_NOTENDED; /* Indicate in middle of message */
1952 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1959 #ifndef DISABLE_WELLKNOWN
1962 bsmtp_transaction_linecount = receive_linecount;
1967 f.smtp_in_quit = TRUE;
1974 /* The function moan_smtp_batch() does not return. */
1975 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1980 /* The function moan_smtp_batch() does not return. */
1981 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1986 /* The function moan_smtp_batch() does not return. */
1987 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1992 return done - 2; /* Convert yield values */
2000 smtp_log_tls_fail(const uschar * errstr)
2002 const uschar * conn_info = smtp_get_connection_info();
2004 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2005 /* I'd like to get separated H= here, but too hard for now */
2007 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2021 socklen_t len = sizeof(is_fastopen);
2023 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2024 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2026 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2031 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2032 f.tcp_in_fastopen = TRUE;
2035 else DEBUG(D_receive)
2036 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2038 # elif defined(TCP_INFO)
2039 struct tcp_info tinfo;
2040 socklen_t len = sizeof(tinfo);
2042 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2043 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2044 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2047 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2048 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2052 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2055 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2056 f.tcp_in_fastopen = TRUE;
2058 else DEBUG(D_receive)
2059 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2066 log_connect_tls_drop(const uschar * what, const uschar * log_msg)
2068 if (log_reject_target)
2070 gstring * g = s_tlslog(NULL);
2071 uschar * tls = string_from_gstring(g);
2073 log_write(L_connection_reject,
2074 log_reject_target, "%s%s%s dropped by %s%s%s",
2075 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
2076 host_and_ident(TRUE),
2079 log_msg ? US": " : US"", log_msg);
2084 /*************************************************
2085 * Start an SMTP session *
2086 *************************************************/
2088 /* This function is called at the start of an SMTP session. Thereafter,
2089 smtp_setup_msg() is called to initiate each separate message. This
2090 function does host-specific testing, and outputs the banner line.
2093 Returns: FALSE if the session can not continue; something has
2094 gone wrong, or the connection to the host is blocked
2098 smtp_start_session(void)
2101 uschar *user_msg, *log_msg;
2106 gettimeofday(&smtp_connection_start, NULL);
2107 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2108 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2111 /* Default values for certain variables */
2113 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2114 smtp_mailcmd_count = 0;
2115 count_nonmail = TRUE_UNSET;
2116 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2117 smtp_delay_mail = smtp_rlm_base;
2118 fl.auth_advertised = FALSE;
2119 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2120 f.pipelining_enable = TRUE;
2121 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2122 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2124 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2125 authentication settings from -oMaa to remain in force. */
2127 if (!host_checking && !f.sender_host_notsocket)
2128 sender_host_auth_pubname = sender_host_authenticated = NULL;
2129 authenticated_by = NULL;
2132 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2133 tls_in.ourcert = tls_in.peercert = NULL;
2135 tls_in.ocsp = OCSP_NOT_REQ;
2136 fl.tls_advertised = FALSE;
2138 fl.dsn_advertised = FALSE;
2140 fl.smtputf8_advertised = FALSE;
2143 /* Reset ACL connection variables */
2147 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2149 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, GET_TAINTED);
2151 smtp_cmd_buffer[0] = 0;
2152 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2154 /* For batched input, the protocol setting can be overridden from the
2155 command line by a trusted caller. */
2157 if (smtp_batched_input)
2159 if (!received_protocol) received_protocol = US"local-bsmtp";
2162 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2163 reset later if any of EHLO/AUTH/STARTTLS are received. */
2167 (sender_host_address ? protocols : protocols_local) [pnormal];
2169 /* Set up the buffer for inputting using direct read() calls, and arrange to
2170 call the local functions instead of the standard C ones. */
2174 receive_getc = smtp_getc;
2175 receive_getbuf = smtp_getbuf;
2176 receive_get_cache = smtp_get_cache;
2177 receive_hasc = smtp_hasc;
2178 receive_ungetc = smtp_ungetc;
2179 receive_feof = smtp_feof;
2180 receive_ferror = smtp_ferror;
2181 lwr_receive_getc = NULL;
2182 lwr_receive_getbuf = NULL;
2183 lwr_receive_hasc = NULL;
2184 lwr_receive_ungetc = NULL;
2186 /* Set up the message size limit; this may be host-specific */
2188 GET_OPTION("message_size_limit");
2189 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2190 if (expand_string_message)
2192 if (thismessage_size_limit == -1)
2193 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2194 "%s", expand_string_message);
2196 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2197 "%s", expand_string_message);
2198 smtp_closedown(US"Temporary local problem - please try later");
2202 /* When a message is input locally via the -bs or -bS options, sender_host_
2203 unknown is set unless -oMa was used to force an IP address, in which case it
2204 is checked like a real remote connection. When -bs is used from inetd, this
2205 flag is not set, causing the sending host to be checked. The code that deals
2206 with IP source routing (if configured) is never required for -bs or -bS and
2207 the flag sender_host_notsocket is used to suppress it.
2209 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2210 reserve for certain hosts and/or networks. */
2212 if (!f.sender_host_unknown)
2215 BOOL reserved_host = FALSE;
2217 /* Look up IP options (source routing info) on the socket if this is not an
2218 -oMa "host", and if any are found, log them and drop the connection.
2220 Linux (and others now, see below) is different to everyone else, so there
2221 has to be some conditional compilation here. Versions of Linux before 2.1.15
2222 used a structure whose name was "options". Somebody finally realized that
2223 this name was silly, and it got changed to "ip_options". I use the
2224 newer name here, but there is a fudge in the script that sets up os.h
2225 to define a macro in older Linux systems.
2227 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2228 glibc 2, which has chosen ip_opts for the structure name. This is now
2229 really a glibc thing rather than a Linux thing, so the condition name
2230 has been changed to reflect this. It is relevant also to GNU/Hurd.
2232 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2233 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2234 a special macro defined in the os.h file.
2236 Some DGUX versions on older hardware appear not to support IP options at
2237 all, so there is now a general macro which can be set to cut out this
2240 How to do this properly in IPv6 is not yet known. */
2242 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2244 # ifdef GLIBC_IP_OPTIONS
2245 # if (!defined __GLIBC__) || (__GLIBC__ < 2)
2250 # elif defined DARWIN_IP_OPTIONS
2256 if (!host_checking && !f.sender_host_notsocket)
2259 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2260 struct ip_options *ipopt = store_get(optlen, GET_UNTAINTED);
2261 # elif OPTSTYLE == 2
2262 struct ip_opts ipoptblock;
2263 struct ip_opts *ipopt = &ipoptblock;
2264 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2266 struct ipoption ipoptblock;
2267 struct ipoption *ipopt = &ipoptblock;
2268 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2271 /* Occasional genuine failures of getsockopt() have been seen - for
2272 example, "reset by peer". Therefore, just log and give up on this
2273 call, unless the error is ENOPROTOOPT. This error is given by systems
2274 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2275 of writing. So for that error, carry on - we just can't do an IP options
2278 DEBUG(D_receive) debug_printf("checking for IP options\n");
2280 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2283 if (errno != ENOPROTOOPT)
2285 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2286 host_and_ident(FALSE), strerror(errno));
2287 smtp_printf("451 SMTP service not available\r\n", SP_NO_MORE);
2292 /* Deal with any IP options that are set. On the systems I have looked at,
2293 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2294 more logging data than will fit in big_buffer. Nevertheless, after somebody
2295 questioned this code, I've added in some paranoid checking. */
2297 else if (optlen > 0)
2299 uschar * p = big_buffer;
2300 uschar * pend = big_buffer + big_buffer_size;
2303 struct in_addr addr;
2306 uschar * optstart = US (ipopt->__data);
2307 # elif OPTSTYLE == 2
2308 uschar * optstart = US (ipopt->ip_opts);
2310 uschar * optstart = US (ipopt->ipopt_list);
2313 DEBUG(D_receive) debug_printf("IP options exist\n");
2315 Ustrcpy(p, "IP options on incoming call:");
2318 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2333 string_format(p, pend-p, " %s [@%s",
2334 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2335 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr)))))
2336 # elif OPTSTYLE == 2
2337 string_format(p, pend-p, " %s [@%s",
2338 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2339 inet_ntoa(ipopt->ip_dst))
2341 string_format(p, pend-p, " %s [@%s",
2342 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2343 inet_ntoa(ipopt->ipopt_dst))
2352 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2354 while (optcount-- > 0)
2356 memcpy(&addr, adptr, sizeof(addr));
2357 if (!string_format(p, pend - p - 1, "%s%s",
2358 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2364 adptr += sizeof(struct in_addr);
2372 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2375 for (int i = 0; i < opt[1]; i++)
2376 p += sprintf(CS p, "%2.2x ", opt[i]);
2384 log_write(0, LOG_MAIN, "%s", big_buffer);
2386 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2388 log_write(0, LOG_MAIN|LOG_REJECT,
2389 "connection from %s refused (IP options)", host_and_ident(FALSE));
2391 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2395 /* Length of options = 0 => there are no options */
2397 else DEBUG(D_receive) debug_printf("no IP options found\n");
2399 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2401 /* Set keep-alive in socket options. The option is on by default. This
2402 setting is an attempt to get rid of some hanging connections that stick in
2403 read() when the remote end (usually a dialup) goes away. */
2405 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2406 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2408 /* If the current host matches host_lookup, set the name by doing a
2409 reverse lookup. On failure, sender_host_name will be NULL and
2410 host_lookup_failed will be TRUE. This may or may not be serious - optional
2413 if (verify_check_host(&host_lookup) == OK)
2415 (void)host_name_lookup();
2416 host_build_sender_fullhost();
2419 /* Delay this until we have the full name, if it is looked up. */
2421 set_process_info("handling incoming connection from %s",
2422 host_and_ident(FALSE));
2424 /* Expand smtp_receive_timeout, if needed */
2426 if (smtp_receive_timeout_s)
2429 if ( !(exp = expand_string(smtp_receive_timeout_s))
2431 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2433 log_write(0, LOG_MAIN|LOG_PANIC,
2434 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2437 /* Test for explicit connection rejection */
2439 if (verify_check_host(&host_reject_connection) == OK)
2441 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2442 "from %s (host_reject_connection)", host_and_ident(FALSE));
2444 if (!tls_in.on_connect)
2446 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2450 /* Test with TCP Wrappers if so configured. There is a problem in that
2451 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2452 such as disks dying. In these cases, it is desirable to reject with a 4xx
2453 error instead of a 5xx error. There isn't a "right" way to detect such
2454 problems. The following kludge is used: errno is zeroed before calling
2455 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2456 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2459 #ifdef USE_TCP_WRAPPERS
2461 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2462 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2463 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2464 expand_string_message);
2466 if (!hosts_ctl(tcp_wrappers_name,
2467 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2468 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2469 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2471 if (errno == 0 || errno == ENOENT)
2473 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2474 log_write(L_connection_reject,
2475 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2476 "(tcp wrappers)", host_and_ident(FALSE));
2477 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2481 int save_errno = errno;
2482 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2483 "errno value %d\n", save_errno);
2484 log_write(L_connection_reject,
2485 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2486 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2487 smtp_printf("451 Temporary local problem - please try later\r\n", SP_NO_MORE);
2493 /* Check for reserved slots. The value of smtp_accept_count has already been
2494 incremented to include this process. */
2496 if (smtp_accept_max > 0 &&
2497 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2499 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2501 log_write(L_connection_reject,
2502 LOG_MAIN, "temporarily refused connection from %s: not in "
2503 "reserve list: connected=%d max=%d reserve=%d%s",
2504 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2505 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2506 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2507 "please try again later\r\n", SP_NO_MORE, smtp_active_hostname);
2510 reserved_host = TRUE;
2513 /* If a load level above which only messages from reserved hosts are
2514 accepted is set, check the load. For incoming calls via the daemon, the
2515 check is done in the superior process if there are no reserved hosts, to
2516 save a fork. In all cases, the load average will already be available
2517 in a global variable at this point. */
2519 if (smtp_load_reserve >= 0 &&
2520 load_average > smtp_load_reserve &&
2522 verify_check_host(&smtp_reserve_hosts) != OK)
2524 log_write(L_connection_reject,
2525 LOG_MAIN, "temporarily refused connection from %s: not in "
2526 "reserve list and load average = %.2f", host_and_ident(FALSE),
2527 (double)load_average/1000.0);
2528 smtp_printf("421 %s: Too much load; please try again later\r\n", SP_NO_MORE,
2529 smtp_active_hostname);
2533 /* Determine whether unqualified senders or recipients are permitted
2534 for this host. Unfortunately, we have to do this every time, in order to
2535 set the flags so that they can be inspected when considering qualifying
2536 addresses in the headers. For a site that permits no qualification, this
2537 won't take long, however. */
2539 f.allow_unqualified_sender =
2540 verify_check_host(&sender_unqualified_hosts) == OK;
2542 f.allow_unqualified_recipient =
2543 verify_check_host(&recipient_unqualified_hosts) == OK;
2545 /* Determine whether HELO/EHLO is required for this host. The requirement
2546 can be hard or soft. */
2548 fl.helo_verify_required = verify_check_host(&helo_verify_hosts) == OK;
2549 if (!fl.helo_verify_required)
2550 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2552 /* Determine whether this hosts is permitted to send syntactic junk
2553 after a HELO or EHLO command. */
2555 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2558 /* Expand recipients_max, if needed */
2560 uschar * rme = expand_string(recipients_max);
2561 recipients_max_expanded = atoi(CCS rme);
2563 /* For batch SMTP input we are now done. */
2565 if (smtp_batched_input) return TRUE;
2567 #if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS) || defined(EXPERIMENTAL_XCLIENT)
2568 proxy_session = FALSE;
2571 #ifdef SUPPORT_PROXY
2572 /* If valid Proxy Protocol source is connecting, set up session.
2573 Failure will not allow any SMTP function other than QUIT. */
2575 f.proxy_session_failed = FALSE;
2576 if (proxy_protocol_host())
2578 os_non_restarting_signal(SIGALRM, command_timeout_handler);
2579 proxy_protocol_setup();
2583 /* Run the connect ACL if it exists */
2586 GET_OPTION("acl_smtp_connect");
2587 if (acl_smtp_connect)
2590 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2594 if (tls_in.on_connect)
2595 log_connect_tls_drop(US"'connect' ACL", log_msg);
2598 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2603 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2604 smtps port for use with older style SSL MTAs. */
2607 if (tls_in.on_connect)
2609 if (tls_server_start(&user_msg) != OK)
2610 return smtp_log_tls_fail(user_msg);
2611 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
2615 /* Output the initial message for a two-way SMTP connection. It may contain
2616 newlines, which then cause a multi-line response to be given. */
2618 code = US"220"; /* Default status code */
2619 esc = US""; /* Default extended status code */
2620 esclen = 0; /* Length of esc */
2626 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2630 esclen = codelen - 4;
2635 GET_OPTION("smtp_banner");
2636 if (!(s = expand_string(smtp_banner)))
2638 log_write(0, f.expand_string_forcedfail ? LOG_MAIN : LOG_MAIN|LOG_PANIC_DIE,
2639 "Expansion of \"%s\" (smtp_banner) failed: %s",
2640 smtp_banner, expand_string_message);
2641 /* for force-fail */
2643 if (tls_in.on_connect) tls_close(NULL, TLS_SHUTDOWN_WAIT);
2649 /* Remove any terminating newlines; might as well remove trailing space too */
2652 while (p > s && isspace(p[-1])) p--;
2653 s = string_copyn(s, p-s);
2655 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2656 is all contained in a single IP packet. The original code wrote out the
2657 greeting using several calls to fprint/fputc, and on busy servers this could
2658 cause it to be split over more than one packet - which caused CC:Mail to fall
2659 over when it got the second part of the greeting after sending its first
2660 command. Sigh. To try to avoid this, build the complete greeting message
2661 first, and output it in one fell swoop. This gives a better chance of it
2662 ending up as a single packet. */
2664 ss = string_get(256);
2667 do /* At least once, in case we have an empty string */
2670 uschar *linebreak = Ustrchr(p, '\n');
2671 ss = string_catn(ss, code, 3);
2675 ss = string_catn(ss, US" ", 1);
2679 len = linebreak - p;
2680 ss = string_catn(ss, US"-", 1);
2682 ss = string_catn(ss, esc, esclen);
2683 ss = string_catn(ss, p, len);
2684 ss = string_catn(ss, US"\r\n", 2);
2690 /* Before we write the banner, check that there is no input pending, unless
2691 this synchronisation check is disabled. */
2693 #ifndef DISABLE_PIPE_CONNECT
2694 fl.pipe_connect_acceptable =
2695 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
2698 if (fl.pipe_connect_acceptable)
2699 f.smtp_in_early_pipe_used = TRUE;
2705 unsigned n = smtp_inend - smtp_inptr;
2706 if (n > 128) n = 128;
2708 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2709 "synchronization error (input sent without waiting for greeting): "
2710 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2711 string_printing(string_copyn(smtp_inptr, n)));
2712 smtp_printf("554 SMTP synchronization error\r\n", SP_NO_MORE);
2716 /* Now output the banner */
2717 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
2720 #ifndef DISABLE_PIPE_CONNECT
2721 fl.pipe_connect_acceptable && pipeline_connect_sends(),
2727 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2728 handshake arrived. If so we must have managed a TFO. */
2731 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
2741 /*************************************************
2742 * Handle SMTP syntax and protocol errors *
2743 *************************************************/
2745 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2746 to do so. Then transmit the error response. The return value depends on the
2747 number of syntax and protocol errors in this SMTP session.
2750 type error type, given as a log flag bit
2751 code response code; <= 0 means don't send a response
2752 data data to reflect in the response (can be NULL)
2753 errmess the error message
2755 Returns: -1 limit of syntax/protocol errors NOT exceeded
2756 +1 limit of syntax/protocol errors IS exceeded
2758 These values fit in with the values of the "done" variable in the main
2759 processing loop in smtp_setup_msg(). */
2762 synprot_error(int type, int code, uschar *data, uschar *errmess)
2766 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2767 type == L_smtp_syntax_error ? "syntax" : "protocol",
2768 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2770 if (++synprot_error_count > smtp_max_synprot_errors)
2773 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2774 "syntax or protocol errors (last command was \"%s\", %Y)",
2775 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
2782 smtp_printf("%d%c%s%s%s\r\n", SP_NO_MORE, code, yield == 1 ? '-' : ' ',
2783 data ? data : US"", data ? US": " : US"", errmess);
2785 smtp_printf("%d Too many syntax or protocol errors\r\n", SP_NO_MORE, code);
2794 /*************************************************
2795 * Send SMTP response, possibly multiline *
2796 *************************************************/
2798 /* There are, it seems, broken clients out there that cannot handle multiline
2799 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2800 output nothing for non-final calls, and only the first line for anything else.
2803 code SMTP code, may involve extended status codes
2804 codelen length of smtp code; if > 4 there's an ESC
2805 final FALSE if the last line isn't the final line
2806 msg message text, possibly containing newlines
2812 smtp_respond(uschar * code, int codelen, BOOL final, uschar * msg)
2817 if (!final && f.no_multiline_responses) return;
2822 esclen = codelen - 4;
2825 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2826 have had the same. Note: this code is also present in smtp_printf(). It would
2827 be tidier to have it only in one place, but when it was added, it was easier to
2828 do it that way, so as not to have to mess with the code for the RCPT command,
2829 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2831 if (fl.rcpt_in_progress)
2833 if (!rcpt_smtp_response)
2834 rcpt_smtp_response = string_copy(msg);
2835 else if (fl.rcpt_smtp_response_same &&
2836 Ustrcmp(rcpt_smtp_response, msg) != 0)
2837 fl.rcpt_smtp_response_same = FALSE;
2838 fl.rcpt_in_progress = FALSE;
2841 /* Now output the message, splitting it up into multiple lines if necessary.
2842 We only handle pipelining these responses as far as nonfinal/final groups,
2843 not the whole MAIL/RCPT/DATA response set. */
2846 if (!(nl = Ustrchr(msg, '\n')))
2848 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
2851 else if (nl[1] == 0 || f.no_multiline_responses)
2853 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
2854 (int)(nl - msg), msg);
2859 smtp_printf("%.3s-%.*s%.*s\r\n", SP_MORE, code, esclen, esc, (int)(nl - msg), msg);
2861 Uskip_whitespace(&msg);
2868 /*************************************************
2869 * Parse user SMTP message *
2870 *************************************************/
2872 /* This function allows for user messages overriding the response code details
2873 by providing a suitable response code string at the start of the message
2874 user_msg. Check the message for starting with a response code and optionally an
2875 extended status code. If found, check that the first digit is valid, and if so,
2876 change the code pointer and length to use the replacement. An invalid code
2877 causes a panic log; in this case, if the log messages is the same as the user
2878 message, we must also adjust the value of the log message to show the code that
2879 is actually going to be used (the original one).
2881 This function is global because it is called from receive.c as well as within
2884 Note that the code length returned includes the terminating whitespace
2885 character, which is always included in the regex match.
2888 code SMTP code, may involve extended status codes
2889 codelen length of smtp code; if > 4 there's an ESC
2891 log_msg optional log message, to be adjusted with the new SMTP code
2892 check_valid if true, verify the response code
2898 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2904 if (!msg || !*msg || !regex_match(regex_smtp_code, *msg, -1, &match))
2907 len = Ustrlen(match);
2908 if (check_valid && (*msg)[0] != (*code)[0])
2910 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2911 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2912 if (log_msg && *log_msg == *msg)
2913 *log_msg = string_sprintf("%s %s", *code, *log_msg + len);
2918 *codelen = len; /* Includes final space */
2920 *msg += len; /* Chop the code off the message */
2927 /*************************************************
2928 * Handle an ACL failure *
2929 *************************************************/
2931 /* This function is called when acl_check() fails. As well as calls from within
2932 this module, it is called from receive.c for an ACL after DATA. It sorts out
2933 logging the incident, and sends the error response. A message containing
2934 newlines is turned into a multiline SMTP response, but for logging, only the
2937 There's a table of default permanent failure response codes to use in
2938 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2939 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2940 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2941 state, because there are broken clients that try VRFY before RCPT. A 5xx
2942 response should be given only when the address is positively known to be
2943 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2944 no explicit code, but if there is one we let it know best.
2945 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2947 From Exim 4.63, it is possible to override the response code details by
2948 providing a suitable response code string at the start of the message provided
2949 in user_msg. The code's first digit is checked for validity.
2952 where where the ACL was called from
2954 user_msg a message that can be included in an SMTP response
2955 log_msg a message for logging
2957 Returns: 0 in most cases
2958 2 if the failure code was FAIL_DROP, in which case the
2959 SMTP connection should be dropped (this value fits with the
2960 "done" variable in smtp_setup_msg() below)
2964 smtp_handle_acl_fail(int where, int rc, uschar * user_msg, uschar * log_msg)
2966 BOOL drop = rc == FAIL_DROP;
2970 uschar *sender_info = US"";
2973 if (drop) rc = FAIL;
2975 /* Set the default SMTP code, and allow a user message to change it. */
2977 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2978 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2979 where != ACL_WHERE_VRFY);
2981 /* Get info for logging.
2982 We used to have sender_address here; however, there was a bug that was not
2983 updating sender_address after a rewrite during a verify. When this bug was
2984 fixed, sender_address at this point became the rewritten address. I'm not sure
2985 this is what should be logged, so I've changed to logging the unrewritten
2986 address to retain backward compatibility. */
2990 #ifdef WITH_CONTENT_SCAN
2991 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
2993 case ACL_WHERE_PREDATA: what = US"DATA"; break;
2994 case ACL_WHERE_DATA: what = US"after DATA"; break;
2995 #ifndef DISABLE_PRDR
2996 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
3000 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
3003 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
3005 uschar * s = smtp_cmd_data;
3007 lim = s - smtp_cmd_data; /* stop after method */
3009 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
3014 case ACL_WHERE_RCPT:
3015 case ACL_WHERE_DATA:
3016 #ifdef WITH_CONTENT_SCAN
3017 case ACL_WHERE_MIME:
3019 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3020 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3021 sender_host_authenticated ? US" A=" : US"",
3022 sender_host_authenticated ? sender_host_authenticated : US"",
3023 sender_host_authenticated && authenticated_id ? US":" : US"",
3024 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3029 /* If there's been a sender verification failure with a specific message, and
3030 we have not sent a response about it yet, do so now, as a preliminary line for
3031 failures, but not defers. However, always log it for defer, and log it for fail
3032 unless the sender_verify_fail log selector has been turned off. */
3034 if (sender_verified_failed &&
3035 !testflag(sender_verified_failed, af_sverify_told))
3037 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3038 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3040 setflag(sender_verified_failed, af_sverify_told);
3042 if (rc != FAIL || LOGGING(sender_verify_fail))
3043 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3044 host_and_ident(TRUE),
3045 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3046 sender_verified_failed->address,
3047 (sender_verified_failed->message == NULL)? US"" :
3048 string_sprintf(": %s", sender_verified_failed->message));
3050 if (rc == FAIL && sender_verified_failed->user_message)
3051 smtp_respond(smtp_code, codelen, SR_NOT_FINAL, string_sprintf(
3052 testflag(sender_verified_failed, af_verify_pmfail)?
3053 "Postmaster verification failed while checking <%s>\n%s\n"
3054 "Several RFCs state that you are required to have a postmaster\n"
3055 "mailbox for each mail domain. This host does not accept mail\n"
3056 "from domains whose servers reject the postmaster address."
3058 testflag(sender_verified_failed, af_verify_nsfail)?
3059 "Callback setup failed while verifying <%s>\n%s\n"
3060 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3061 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3062 "RFC requirements, and stops you from receiving standard bounce\n"
3063 "messages. This host does not accept mail from domains whose servers\n"
3066 "Verification failed for <%s>\n%s",
3067 sender_verified_failed->address,
3068 sender_verified_failed->user_message));
3070 fl.rcpt_in_progress = save_rcpt_in_progress;
3073 /* Sort out text for logging */
3075 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3076 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3078 /* Send permanent failure response to the command, but the code used isn't
3079 always a 5xx one - see comments at the start of this function. If the original
3080 rc was FAIL_DROP we drop the connection and yield 2. */
3083 smtp_respond(smtp_code, codelen, SR_FINAL,
3084 user_msg ? user_msg : US"Administrative prohibition");
3086 /* Send temporary failure response to the command. Don't give any details,
3087 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3088 verb, and for a header verify when smtp_return_error_details is set.
3090 This conditional logic is all somewhat of a mess because of the odd
3091 interactions between temp_details and return_error_details. One day it should
3092 be re-implemented in a tidier fashion. */
3095 if (f.acl_temp_details && user_msg)
3097 if ( smtp_return_error_details
3098 && sender_verified_failed
3099 && sender_verified_failed->message
3101 smtp_respond(smtp_code, codelen, SR_NOT_FINAL, sender_verified_failed->message);
3103 smtp_respond(smtp_code, codelen, SR_FINAL, user_msg);
3106 smtp_respond(smtp_code, codelen, SR_FINAL,
3107 US"Temporary local problem - please try later");
3109 /* Log the incident to the logs that are specified by log_reject_target
3110 (default main, reject). This can be empty to suppress logging of rejections. If
3111 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3112 is closing if required and return 2. */
3114 if (log_reject_target)
3117 gstring * g = s_tlslog(NULL);
3118 uschar * tls = string_from_gstring(g);
3119 if (!tls) tls = US"";
3121 uschar * tls = US"";
3123 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3124 log_reject_target, "%s%s%s %s%srejected %s%s",
3125 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3126 host_and_ident(TRUE),
3129 rc == FAIL ? US"" : US"temporarily ",
3133 if (!drop) return 0;
3135 log_close_event(US"by DROP in ACL");
3137 /* Run the not-quit ACL, but without any custom messages. This should not be a
3138 problem, because we get here only if some other ACL has issued "drop", and
3139 in that case, *its* custom messages will have been used above. */
3141 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3143 /* An overenthusiastic fail2ban/iptables implimentation has been seen to result
3144 in the TCP conn staying open, and retrying, despite this process exiting. A
3145 malicious client could possibly do the same, tying up server netowrking
3146 resources. Close the socket explicitly to try to avoid that (there's a note in
3147 the Linux socket(7) manpage, SO_LINGER para, to the effect that exim() without
3148 close() results in the socket always lingering). */
3150 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3151 DEBUG(D_any) debug_printf_indent("SMTP(close)>>\n");
3152 (void) fclose(smtp_in);
3153 (void) fclose(smtp_out);
3161 /*************************************************
3162 * Handle SMTP exit when QUIT is not given *
3163 *************************************************/
3165 /* This function provides a logging/statistics hook for when an SMTP connection
3166 is dropped on the floor or the other end goes away. It's a global function
3167 because it's called from receive.c as well as this module. As well as running
3168 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3169 response, either with a custom message from the ACL, or using a default. There
3170 is one case, however, when no message is output - after "drop". In that case,
3171 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3172 passed to this function.
3174 In case things go wrong while processing this function, causing an error that
3175 may re-enter this function, there is a recursion check.
3178 reason What $smtp_notquit_reason will be set to in the ACL;
3179 if NULL, the ACL is not run
3180 code The error code to return as part of the response
3181 defaultrespond The default message if there's no user_msg
3187 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3190 uschar *user_msg = NULL;
3191 uschar *log_msg = NULL;
3193 /* Check for recursive call */
3195 if (fl.smtp_exit_function_called)
3197 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3201 fl.smtp_exit_function_called = TRUE;
3203 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3205 GET_OPTION("acl_smtp_notquit");
3206 if (acl_smtp_notquit && reason)
3208 smtp_notquit_reason = reason;
3209 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3210 &log_msg)) == ERROR)
3211 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3215 /* If the connection was dropped, we certainly are no longer talking TLS */
3216 tls_in.active.sock = -1;
3218 /* Write an SMTP response if we are expected to give one. As the default
3219 responses are all internal, they should be reasonable size. */
3221 if (code && defaultrespond)
3224 smtp_respond(code, 3, SR_FINAL, user_msg);
3230 va_start(ap, defaultrespond);
3231 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3233 smtp_printf("%s %Y\r\n", SP_NO_MORE, code, g);
3242 /*************************************************
3243 * Verify HELO argument *
3244 *************************************************/
3246 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3247 matched. It is also called from ACL processing if verify = helo is used and
3248 verification was not previously tried (i.e. helo_try_verify_hosts was not
3249 matched). The result of its processing is to set helo_verified and
3250 helo_verify_failed. These variables should both be FALSE for this function to
3253 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3254 for IPv6 ::ffff: literals.
3257 Returns: TRUE if testing was completed;
3258 FALSE on a temporary failure
3262 smtp_verify_helo(void)
3266 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3269 if (sender_helo_name == NULL)
3271 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3274 /* Deal with the case of -bs without an IP address */
3276 else if (sender_host_address == NULL)
3278 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3279 f.helo_verified = TRUE;
3282 /* Deal with the more common case when there is a sending IP address */
3284 else if (sender_helo_name[0] == '[')
3286 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3287 Ustrlen(sender_host_address)) == 0;
3290 if (!f.helo_verified)
3292 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3293 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3294 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3299 { if (f.helo_verified) debug_printf("matched host address\n"); }
3302 /* Do a reverse lookup if one hasn't already given a positive or negative
3303 response. If that fails, or the name doesn't match, try checking with a forward
3308 if (sender_host_name == NULL && !host_lookup_failed)
3309 yield = host_name_lookup() != DEFER;
3311 /* If a host name is known, check it and all its aliases. */
3313 if (sender_host_name)
3314 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3316 sender_helo_dnssec = sender_host_dnssec;
3317 HDEBUG(D_receive) debug_printf("matched host name\n");
3321 uschar **aliases = sender_host_aliases;
3323 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3325 sender_helo_dnssec = sender_host_dnssec;
3329 HDEBUG(D_receive) if (f.helo_verified)
3330 debug_printf("matched alias %s\n", *(--aliases));
3333 /* Final attempt: try a forward lookup of the helo name */
3335 if (!f.helo_verified)
3339 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3341 {.request = US"*", .require = US""};
3343 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3345 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3346 NULL, NULL, NULL, &d, NULL, NULL);
3347 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3348 for (host_item * hh = &h; hh; hh = hh->next)
3349 if (Ustrcmp(hh->address, sender_host_address) == 0)
3351 f.helo_verified = TRUE;
3352 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3354 debug_printf("IP address for %s matches calling address\n"
3355 "Forward DNS security status: %sverified\n",
3356 sender_helo_name, sender_helo_dnssec ? "" : "un");
3362 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3369 /*************************************************
3370 * Send user response message *
3371 *************************************************/
3373 /* This function is passed a default response code and a user message. It calls
3374 smtp_message_code() to check and possibly modify the response code, and then
3375 calls smtp_respond() to transmit the response. I put this into a function
3376 just to avoid a lot of repetition.
3379 code the response code
3380 user_msg the user message
3386 smtp_user_msg(uschar * code, uschar * user_msg)
3389 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3390 smtp_respond(code, len, SR_FINAL, user_msg);
3396 smtp_in_auth(auth_instance *au, uschar ** smtp_resp, uschar ** errmsg)
3398 const uschar *set_id = NULL;
3401 /* Set up globals for error messages */
3403 authenticator_name = au->name;
3404 driver_srcfile = au->srcfile;
3405 driver_srcline = au->srcline;
3407 /* Run the checking code, passing the remainder of the command line as
3408 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3409 it as the only set numerical variable. The authenticator may set $auth<n>
3410 and also set other numeric variables. The $auth<n> variables are preferred
3411 nowadays; the numerical variables remain for backwards compatibility.
3413 Afterwards, have a go at expanding the set_id string, even if
3414 authentication failed - for bad passwords it can be useful to log the
3415 userid. On success, require set_id to expand and exist, and put it in
3416 authenticated_id. Save this in permanent store, as the working store gets
3417 reset at HELO, RSET, etc. */
3419 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3421 expand_nlength[0] = 0; /* $0 contains nothing */
3423 rc = (au->info->servercode)(au, smtp_cmd_data);
3424 if (au->set_id) set_id = expand_string(au->set_id);
3425 expand_nmax = -1; /* Reset numeric variables */
3426 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3427 driver_srcfile = authenticator_name = NULL; driver_srcline = 0;
3429 /* The value of authenticated_id is stored in the spool file and printed in
3430 log lines. It must not contain binary zeros or newline characters. In
3431 normal use, it never will, but when playing around or testing, this error
3432 can (did) happen. To guard against this, ensure that the id contains only
3433 printing characters. */
3435 if (set_id) set_id = string_printing(set_id);
3437 /* For the non-OK cases, set up additional logging data if set_id
3441 set_id = set_id && *set_id
3442 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3444 /* Switch on the result */
3449 if (!au->set_id || set_id) /* Complete success */
3451 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3452 sender_host_authenticated = au->name;
3453 sender_host_auth_pubname = au->public_name;
3454 authentication_failed = FALSE;
3455 authenticated_fail_id = NULL; /* Impossible to already be set? */
3458 (sender_host_address ? protocols : protocols_local)
3459 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3460 *smtp_resp = *errmsg = US"235 Authentication succeeded";
3461 authenticated_by = au;
3465 /* Authentication succeeded, but we failed to expand the set_id string.
3466 Treat this as a temporary error. */
3468 auth_defer_msg = expand_string_message;
3472 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3473 *smtp_resp = string_sprintf("435 Unable to authenticate at present%s",
3474 auth_defer_user_msg);
3475 *errmsg = string_sprintf("435 Unable to authenticate at present%s: %s",
3476 set_id, auth_defer_msg);
3480 *smtp_resp = *errmsg = US"501 Invalid base64 data";
3484 *smtp_resp = *errmsg = US"501 Authentication cancelled";
3488 *smtp_resp = *errmsg = US"553 Initial data not expected";
3492 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3493 *smtp_resp = US"535 Incorrect authentication data";
3494 *errmsg = string_sprintf("535 Incorrect authentication data%s", set_id);
3498 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3499 *smtp_resp = US"435 Internal error";
3500 *errmsg = string_sprintf("435 Internal error%s: return %d from authentication "
3501 "check", set_id, rc);
3513 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3516 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3518 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3520 rd = Ustrlen(recipient) + 1;
3521 /* deconst ok as *recipient was not const */
3522 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3525 smtp_printf("501 %s: recipient address must contain a domain\r\n", SP_NO_MORE,
3527 log_write(L_smtp_syntax_error,
3528 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3529 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3537 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3540 f.smtp_in_quit = TRUE;
3541 incomplete_transaction_log(US"QUIT");
3542 GET_OPTION("acl_smtp_quit");
3544 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3546 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3549 #ifdef EXIM_TCP_CORK
3550 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
3554 smtp_respond(US"221", 3, SR_FINAL, *user_msgp);
3556 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
3558 #ifdef SERVERSIDE_CLOSE_NOWAIT
3559 # ifndef DISABLE_TLS
3560 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3563 log_close_event(US"by QUIT");
3566 # ifndef DISABLE_TLS
3567 tls_close(NULL, TLS_SHUTDOWN_WAIT);
3570 log_close_event(US"by QUIT");
3572 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
3573 The socket should become readble (though with no data) */
3575 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3576 #endif /*!SERVERSIDE_CLOSE_NOWAIT*/
3581 smtp_rset_handler(void)
3584 incomplete_transaction_log(US"RSET");
3585 smtp_printf("250 Reset OK\r\n", SP_NO_MORE);
3586 cmd_list[CL_RSET].is_mail_cmd = FALSE;
3587 if (chunking_state > CHUNKING_OFFERED)
3588 chunking_state = CHUNKING_OFFERED;
3592 #ifndef DISABLE_WELLKNOWN
3594 smtp_wellknown_handler(void)
3596 if (verify_check_host(&wellknown_advertise_hosts) != FAIL)
3598 GET_OPTION("acl_smtp_wellknown");
3599 if (acl_smtp_wellknown)
3601 uschar * user_msg = NULL, * log_msg;
3604 if ((rc = acl_check(ACL_WHERE_WELLKNOWN, NULL, acl_smtp_wellknown,
3605 &user_msg, &log_msg)) != OK)
3606 return smtp_handle_acl_fail(ACL_WHERE_WELLKNOWN, rc, user_msg, log_msg);
3607 else if (!wellknown_response)
3608 return smtp_handle_acl_fail(ACL_WHERE_WELLKNOWN, ERROR, user_msg, log_msg);
3609 smtp_user_msg(US"250", wellknown_response);
3614 smtp_printf("554 not permitted\r\n", SP_NO_MORE);
3615 log_write(0, LOG_MAIN|LOG_REJECT, "rejected \"%s\" from %s",
3616 smtp_cmd_buffer, sender_helo_name, host_and_ident(FALSE));
3623 expand_mailmax(const uschar * s)
3625 if (!(s = expand_cstring(s)))
3626 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
3627 return *s ? Uatoi(s) : 0;
3630 /*************************************************
3631 * Initialize for SMTP incoming message *
3632 *************************************************/
3634 /* This function conducts the initial dialogue at the start of an incoming SMTP
3635 message, and builds a list of recipients. However, if the incoming message
3636 is part of a batch (-bS option) a separate function is called since it would
3637 be messy having tests splattered about all over this function. This function
3638 therefore handles the case where interaction is occurring. The input and output
3639 files are set up in smtp_in and smtp_out.
3641 The global recipients_list is set to point to a vector of recipient_item
3642 blocks, whose number is given by recipients_count. This is extended by the
3643 receive_add_recipient() function. The global variable sender_address is set to
3644 the sender's address. The yield is +1 if a message has been successfully
3645 started, 0 if a QUIT command was encountered or the connection was refused from
3646 the particular host, or -1 if the connection was lost.
3650 Returns: > 0 message successfully started (reached DATA)
3651 = 0 QUIT read or end of file reached or call refused
3656 smtp_setup_msg(void)
3659 BOOL toomany = FALSE;
3660 BOOL discarded = FALSE;
3661 BOOL last_was_rej_mail = FALSE;
3662 BOOL last_was_rcpt = FALSE;
3663 rmark reset_point = store_mark();
3665 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3667 /* Reset for start of new message. We allow one RSET not to be counted as a
3668 nonmail command, for those MTAs that insist on sending it between every
3669 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3670 TLS between messages (an Exim client may do this if it has messages queued up
3671 for the host). Note: we do NOT reset AUTH at this point. */
3673 reset_point = smtp_reset(reset_point);
3674 message_ended = END_NOTSTARTED;
3676 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3678 cmd_list[CL_RSET].is_mail_cmd = TRUE;
3679 cmd_list[CL_HELO].is_mail_cmd = TRUE;
3680 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
3682 cmd_list[CL_STLS].is_mail_cmd = TRUE;
3685 if (lwr_receive_getc != NULL)
3687 /* This should have already happened, but if we've gotten confused,
3688 force a reset here. */
3689 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
3690 bdat_pop_receive_functions();
3693 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3695 had_command_sigterm = 0;
3696 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3698 /* Batched SMTP is handled in a different function. */
3700 if (smtp_batched_input) return smtp_setup_batch_msg();
3703 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3704 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3705 US &off, sizeof(off));
3708 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3709 value. The values are 2 larger than the required yield of the function. */
3713 const uschar **argv;
3714 uschar *etrn_command;
3715 uschar *etrn_serialize_key;
3717 uschar *log_msg, *smtp_code;
3718 uschar *user_msg = NULL;
3719 uschar *recipient = NULL;
3720 uschar *hello = NULL;
3722 BOOL was_rej_mail = FALSE;
3723 BOOL was_rcpt = FALSE;
3724 void (*oldsignal)(int);
3726 int start, end, sender_domain, recipient_domain;
3728 uschar * orcpt = NULL;
3733 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3734 if ( tls_in.active.sock >= 0
3736 && tls_in.certificate_verified
3737 && cmd_list[CL_TLAU].is_mail_cmd
3740 cmd_list[CL_TLAU].is_mail_cmd = FALSE;
3742 for (auth_instance * au = auths; au; au = au->next)
3743 if (strcmpic(US"tls", au->driver_name) == 0)
3745 GET_OPTION("acl_smtp_auth");
3747 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3748 &user_msg, &log_msg)) != OK
3750 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3753 smtp_cmd_data = NULL;
3755 if (smtp_in_auth(au, &s, &ss) == OK)
3756 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3759 DEBUG(D_auth) debug_printf("tls auth not succeeded\n");
3760 #ifndef DISABLE_EVENT
3762 uschar * save_name = sender_host_authenticated, * logmsg;
3763 sender_host_authenticated = au->name;
3764 if ((logmsg = event_raise(event_action, US"auth:fail", s, NULL)))
3765 log_write(0, LOG_MAIN, "%s", logmsg);
3766 sender_host_authenticated = save_name;
3776 switch(smtp_read_command(
3777 #ifndef DISABLE_PIPE_CONNECT
3778 !fl.pipe_connect_acceptable,
3782 GETC_BUFFER_UNLIMITED))
3784 /* The AUTH command is not permitted to occur inside a transaction, and may
3785 occur successfully only once per connection. Actually, that isn't quite
3786 true. When TLS is started, all previous information about a connection must
3787 be discarded, so a new AUTH is permitted at that time.
3789 AUTH may only be used when it has been advertised. However, it seems that
3790 there are clients that send AUTH when it hasn't been advertised, some of
3791 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3792 So there's a get-out that allows this to happen.
3794 AUTH is initially labelled as a "nonmail command" so that one occurrence
3795 doesn't get counted. We change the label here so that multiple failing
3796 AUTHS will eventually hit the nonmail threshold. */
3800 authentication_failed = TRUE;
3801 cmd_list[CL_AUTH].is_mail_cmd = FALSE;
3803 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
3805 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3806 US"AUTH command used when not advertised");
3809 if (sender_host_authenticated)
3811 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3812 US"already authenticated");
3817 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3818 US"not permitted in mail transaction");
3824 GET_OPTION("acl_smtp_auth");
3826 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3827 &user_msg, &log_msg)) != OK
3830 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3834 /* Find the name of the requested authentication mechanism. */
3837 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
3838 if (!isalnum(c) && c != '-' && c != '_')
3840 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3841 US"invalid character in authentication mechanism name");
3845 /* If not at the end of the line, we must be at white space. Terminate the
3846 name and move the pointer on to any data that may be present. */
3850 *smtp_cmd_data++ = '\0';
3851 Uskip_whitespace(&smtp_cmd_data);
3854 /* Search for an authentication mechanism which is configured for use
3855 as a server and which has been advertised (unless, sigh, allow_auth_
3856 unadvertised is set). */
3860 uschar * smtp_resp, * errmsg;
3862 for (au = auths; au; au = au->next)
3863 if (strcmpic(s, au->public_name) == 0 && au->server &&
3864 (au->advertised || f.allow_auth_unadvertised))
3869 int rc = smtp_in_auth(au, &smtp_resp, &errmsg);
3871 smtp_printf("%s\r\n", SP_NO_MORE, smtp_resp);
3874 uschar * logmsg = NULL;
3875 #ifndef DISABLE_EVENT
3876 {uschar * save_name = sender_host_authenticated;
3877 sender_host_authenticated = au->name;
3878 logmsg = event_raise(event_action, US"auth:fail", smtp_resp, NULL);
3879 sender_host_authenticated = save_name;
3883 log_write(0, LOG_MAIN|LOG_REJECT, "%s", logmsg);
3885 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3886 au->name, host_and_ident(FALSE), errmsg);
3890 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3891 string_sprintf("%s authentication mechanism not supported", s));
3894 break; /* AUTH_CMD */
3896 /* The HELO/EHLO commands are permitted to appear in the middle of a
3897 session as well as at the beginning. They have the effect of a reset in
3898 addition to their other functions. Their absence at the start cannot be
3899 taken to be an error.
3903 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3904 or 502 failure replies MUST be returned as appropriate. The SMTP
3905 server MUST stay in the same state after transmitting these replies
3906 that it was in before the EHLO was received.
3908 Therefore, we do not do the reset until after checking the command for
3909 acceptability. This change was made for Exim release 4.11. Previously
3910 it did the reset first. */
3923 HELO_EHLO: /* Common code for HELO and EHLO */
3924 cmd_list[CL_HELO].is_mail_cmd = FALSE;
3925 cmd_list[CL_EHLO].is_mail_cmd = FALSE;
3927 /* Reject the HELO if its argument was invalid or non-existent. A
3928 successful check causes the argument to be saved in malloc store. */
3930 if (!check_helo(smtp_cmd_data))
3932 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", SP_NO_MORE, hello);
3934 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3935 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3936 *smtp_cmd_argument == 0 ? US"(no argument given)" :
3937 string_printing(smtp_cmd_argument));
3939 if (++synprot_error_count > smtp_max_synprot_errors)
3941 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3942 "syntax or protocol errors (last command was \"%s\", %Y)",
3943 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3952 /* If sender_host_unknown is true, we have got here via the -bs interface,
3953 not called from inetd. Otherwise, we are running an IP connection and the
3954 host address will be set. If the helo name is the primary name of this
3955 host and we haven't done a reverse lookup, force one now. If helo_verify_required
3956 is set, ensure that the HELO name matches the actual host. If helo_verify
3957 is set, do the same check, but softly. */
3959 if (!f.sender_host_unknown)
3961 BOOL old_helo_verified = f.helo_verified;
3962 uschar * p = smtp_cmd_data;
3964 while (*p && !isspace(*p)) { *p = tolower(*p); p++; }
3967 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3968 because otherwise the log can be confusing. */
3970 if ( !sender_host_name
3971 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3972 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
3973 (void)host_name_lookup();
3975 /* Rebuild the fullhost info to include the HELO name (and the real name
3976 if it was looked up.) */
3978 host_build_sender_fullhost(); /* Rebuild */
3979 set_process_info("handling%s incoming connection from %s",
3980 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
3982 /* Verify if configured. This doesn't give much security, but it does
3983 make some people happy to be able to do it. If helo_verify_required is set,
3984 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3985 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3986 now obsolescent, since the verification can now be requested selectively
3989 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
3990 if (fl.helo_verify_required || fl.helo_verify)
3992 BOOL tempfail = !smtp_verify_helo();
3993 if (!f.helo_verified)
3995 if (fl.helo_verify_required)
3997 smtp_printf("%d %s argument does not match calling host\r\n", SP_NO_MORE,
3998 tempfail? 451 : 550, hello);
3999 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4000 tempfail? "temporarily " : "",
4001 hello, sender_helo_name, host_and_ident(FALSE));
4002 f.helo_verified = old_helo_verified;
4003 break; /* End of HELO/EHLO processing */
4005 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4006 "helo_try_verify_hosts\n", hello);
4012 /* set up SPF context */
4013 spf_conn_init(sender_helo_name, sender_host_address);
4016 /* Apply an ACL check if one is defined; afterwards, recheck
4017 synchronization in case the client started sending in a delay. */
4019 GET_OPTION("acl_smtp_helo");
4021 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4022 &user_msg, &log_msg)) != OK)
4024 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4025 sender_helo_name = NULL;
4026 host_build_sender_fullhost(); /* Rebuild */
4029 #ifndef DISABLE_PIPE_CONNECT
4030 else if (!fl.pipe_connect_acceptable && !check_sync())
4032 else if (!check_sync())
4036 /* Generate an OK reply. The default string includes the ident if present,
4037 and also the IP address if present. Reflecting back the ident is intended
4038 as a deterrent to mail forgers. For maximum efficiency, and also because
4039 some broken systems expect each response to be in a single packet, arrange
4040 that the entire reply is sent in one write(). */
4042 fl.auth_advertised = FALSE;
4043 f.smtp_in_pipelining_advertised = FALSE;
4045 fl.tls_advertised = FALSE;
4047 fl.dsn_advertised = FALSE;
4049 fl.smtputf8_advertised = FALSE;
4052 /* Expand the per-connection message count limit option */
4053 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4055 smtp_code = US"250 "; /* Default response code plus space*/
4058 /* sender_host_name below will be tainted, so save on copy when we hit it */
4059 g = string_get_tainted(24, GET_TAINTED);
4060 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4062 smtp_active_hostname,
4063 sender_ident ? sender_ident : US"",
4064 sender_ident ? US" at " : US"",
4065 sender_host_name ? sender_host_name : sender_helo_name);
4067 if (sender_host_address)
4068 g = string_fmt_append(g, " [%s]", sender_host_address);
4071 /* A user-supplied EHLO greeting may not contain more than one line. Note
4072 that the code returned by smtp_message_code() includes the terminating
4073 whitespace character. */
4079 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4080 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4081 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4083 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4084 "newlines: message truncated: %s", string_printing(s));
4087 g = string_cat(NULL, s);
4090 g = string_catn(g, US"\r\n", 2);
4092 /* If we received EHLO, we must create a multiline response which includes
4093 the functions supported. */
4097 g->s[3] = '-'; /* overwrite the space after the SMTP response code */
4099 /* I'm not entirely happy with this, as an MTA is supposed to check
4100 that it has enough room to accept a message of maximum size before
4101 it sends this. However, there seems little point in not sending it.
4102 The actual size check happens later at MAIL FROM time. By postponing it
4103 till then, VRFY and EXPN can be used after EHLO when space is short. */
4105 if (thismessage_size_limit > 0)
4106 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4107 thismessage_size_limit);
4110 g = string_catn(g, smtp_code, 3);
4111 g = string_catn(g, US"-SIZE\r\n", 7);
4114 #ifndef DISABLE_ESMTP_LIMITS
4115 if ( (smtp_mailcmd_max > 0 || recipients_max_expanded > 0)
4116 && verify_check_host(&limits_advertise_hosts) == OK)
4118 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4119 if (smtp_mailcmd_max > 0)
4120 g = string_fmt_append(g, " MAILMAX=%d", smtp_mailcmd_max);
4121 if (recipients_max_expanded > 0)
4122 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max_expanded);
4123 g = string_catn(g, US"\r\n", 2);
4127 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4128 clean; if it has an 8-bit character in its hand, it just sends it. It
4129 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4130 However, some users want this option simply in order to stop MUAs
4131 mangling messages that contain top-bit-set characters. It is therefore
4132 provided as an option. */
4134 if (accept_8bitmime)
4136 g = string_catn(g, smtp_code, 3);
4137 g = string_catn(g, US"-8BITMIME\r\n", 11);
4140 /* Advertise DSN support if configured to do so. */
4141 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4143 g = string_catn(g, smtp_code, 3);
4144 g = string_catn(g, US"-DSN\r\n", 6);
4145 fl.dsn_advertised = TRUE;
4148 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4149 permitted to issue them; a check is made when any host actually tries. */
4151 GET_OPTION("acl_smtp_etrn");
4154 g = string_catn(g, smtp_code, 3);
4155 g = string_catn(g, US"-ETRN\r\n", 7);
4157 GET_OPTION("acl_smtp_vrfy");
4160 g = string_catn(g, smtp_code, 3);
4161 g = string_catn(g, US"-VRFY\r\n", 7);
4163 GET_OPTION("acl_smtp_expn");
4166 g = string_catn(g, smtp_code, 3);
4167 g = string_catn(g, US"-EXPN\r\n", 7);
4170 /* Exim is quite happy with pipelining, so let the other end know that
4171 it is safe to use it, unless advertising is disabled. */
4173 if ( f.pipelining_enable
4174 && verify_check_host(&pipelining_advertise_hosts) == OK)
4176 g = string_catn(g, smtp_code, 3);
4177 g = string_catn(g, US"-PIPELINING\r\n", 13);
4178 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4179 f.smtp_in_pipelining_advertised = TRUE;
4181 #ifndef DISABLE_PIPE_CONNECT
4182 if (fl.pipe_connect_acceptable)
4184 f.smtp_in_early_pipe_advertised = TRUE;
4185 g = string_catn(g, smtp_code, 3);
4186 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4192 /* If any server authentication mechanisms are configured, advertise
4193 them if the current host is in auth_advertise_hosts. The problem with
4194 advertising always is that some clients then require users to
4195 authenticate (and aren't configurable otherwise) even though it may not
4196 be necessary (e.g. if the host is in host_accept_relay).
4198 RFC 2222 states that SASL mechanism names contain only upper case
4199 letters, so output the names in upper case, though we actually recognize
4200 them in either case in the AUTH command. */
4204 && !sender_host_authenticated
4206 && verify_check_host(&auth_advertise_hosts) == OK
4210 for (auth_instance * au = auths; au; au = au->next)
4212 au->advertised = FALSE;
4215 DEBUG(D_auth+D_expand) debug_printf_indent(
4216 "Evaluating advertise_condition for %s %s athenticator\n",
4217 au->name, au->public_name);
4218 if ( !au->advertise_condition
4219 || expand_check_condition(au->advertise_condition, au->name,
4226 g = string_catn(g, smtp_code, 3);
4227 g = string_catn(g, US"-AUTH", 5);
4229 fl.auth_advertised = TRUE;
4231 saveptr = gstring_length(g);
4232 g = string_catn(g, US" ", 1);
4233 g = string_cat(g, au->public_name);
4234 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4235 au->advertised = TRUE;
4240 if (!first) g = string_catn(g, US"\r\n", 2);
4243 /* RFC 3030 CHUNKING */
4245 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4247 g = string_catn(g, smtp_code, 3);
4248 g = string_catn(g, US"-CHUNKING\r\n", 11);
4249 f.chunking_offered = TRUE;
4250 chunking_state = CHUNKING_OFFERED;
4254 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4255 if it has been included in the binary, and the host matches
4256 tls_advertise_hosts. We must *not* advertise if we are already in a
4257 secure connection. */
4259 if (tls_in.active.sock < 0 &&
4260 verify_check_host(&tls_advertise_hosts) != FAIL)
4262 g = string_catn(g, smtp_code, 3);
4263 g = string_catn(g, US"-STARTTLS\r\n", 11);
4264 fl.tls_advertised = TRUE;
4267 #ifdef EXPERIMENTAL_XCLIENT
4268 if (proxy_session || verify_check_host(&hosts_xclient) != FAIL)
4270 g = string_catn(g, smtp_code, 3);
4271 g = xclient_smtp_advertise_str(g);
4274 #ifndef DISABLE_PRDR
4275 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4278 g = string_catn(g, smtp_code, 3);
4279 g = string_catn(g, US"-PRDR\r\n", 7);
4284 if ( accept_8bitmime
4285 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4287 g = string_catn(g, smtp_code, 3);
4288 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4289 fl.smtputf8_advertised = TRUE;
4292 #ifndef DISABLE_WELLKNOWN
4293 if (verify_check_host(&wellknown_advertise_hosts) != FAIL)
4295 g = string_catn(g, smtp_code, 3);
4296 g = string_catn(g, US"-WELLKNOWN\r\n", 12);
4300 /* Finish off the multiline reply with one that is always available. */
4302 g = string_catn(g, smtp_code, 3);
4303 g = string_catn(g, US" HELP\r\n", 7);
4306 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4311 int len = len_string_from_gstring(g, &ehlo_resp);
4313 if (tls_in.active.sock >= 0)
4314 (void) tls_write(NULL, ehlo_resp, len,
4315 # ifndef DISABLE_PIPE_CONNECT
4316 fl.pipe_connect_acceptable && pipeline_connect_sends());
4322 (void) fwrite(ehlo_resp, 1, len, smtp_out);
4324 DEBUG(D_receive) for (const uschar * t, * s = ehlo_resp;
4325 s && (t = Ustrchr(s, '\r'));
4326 s = t + 2) /* \r\n */
4327 debug_printf("%s %.*s\n",
4328 s == g->s ? "SMTP>>" : " ",
4330 fl.helo_seen = TRUE;
4333 /* Reset the protocol and the state, abandoning any previous message. */
4335 (sender_host_address ? protocols : protocols_local)
4337 ? pextend + (sender_host_authenticated ? pauthed : 0)
4339 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4341 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4342 reset_point = smtp_reset(reset_point);
4344 break; /* HELO/EHLO */
4346 #ifndef DISABLE_WELLKNOWN
4349 smtp_mailcmd_count++;
4350 smtp_wellknown_handler();
4354 #ifdef EXPERIMENTAL_XCLIENT
4357 BOOL fatal = fl.helo_seen;
4362 smtp_mailcmd_count++;
4364 if ((errmsg = xclient_smtp_command(smtp_cmd_data, &resp, &fatal)))
4366 done = synprot_error(L_smtp_syntax_error, resp, NULL, errmsg);
4369 smtp_printf("%d %s\r\n", SP_NO_MORE, resp, errmsg);
4370 log_write(0, LOG_MAIN|LOG_REJECT, "rejected XCLIENT from %s: %s",
4371 host_and_ident(FALSE), errmsg);
4375 fl.helo_seen = FALSE; /* Require another EHLO */
4376 smtp_code = string_sprintf("%d", resp);
4378 /*XXX unclear in spec. if this needs to be an ESMTP banner,
4379 nor whether we get the original client's HELO after (or a proxy fake).
4380 We require that we do; the following HELO/EHLO handling will set
4381 sender_helo_name as normal. */
4383 smtp_printf("%s XCLIENT success\r\n", SP_NO_MORE, smtp_code);
4385 break; /* XCLIENT */
4390 /* The MAIL command requires an address as an operand. All we do
4391 here is to parse it for syntactic correctness. The form "<>" is
4392 a special case which converts into an empty string. The start/end
4393 pointers in the original are not used further for this address, as
4394 it is the canonical extracted address which is all that is kept. */
4398 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4400 was_rej_mail = TRUE; /* Reset if accepted */
4401 env_mail_type_t * mail_args; /* Sanity check & validate args */
4404 if ( fl.helo_verify_required
4405 || verify_check_host(&hosts_require_helo) == OK)
4407 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4408 "HELO/EHLO given", host_and_ident(FALSE));
4409 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4410 US"HELO or EHLO required");
4413 else if (smtp_mailcmd_max < 0)
4414 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4418 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4419 US"sender already given");
4423 if (!*smtp_cmd_data)
4425 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4426 US"MAIL must have an address operand");
4430 /* Check to see if the limit for messages per connection would be
4431 exceeded by accepting further messages. */
4433 if (smtp_mailcmd_max > 0 && smtp_mailcmd_count > smtp_mailcmd_max)
4435 smtp_printf("421 too many messages in this connection\r\n", SP_NO_MORE);
4436 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4437 "messages in one connection", host_and_ident(TRUE));
4441 /* Reset for start of message - even if this is going to fail, we
4442 obviously need to throw away any previous data. */
4444 cancel_cutthrough_connection(TRUE, US"MAIL received");
4445 reset_point = smtp_reset(reset_point);
4447 sender_data = recipient_data = NULL;
4449 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4451 if (fl.esmtp) for(;;)
4453 uschar *name, *value, *end;
4454 unsigned long int size;
4455 BOOL arg_error = FALSE;
4457 if (!extract_option(&name, &value)) break;
4459 for (mail_args = env_mail_type_list;
4460 mail_args->value != ENV_MAIL_OPT_NULL;
4463 if (strcmpic(name, mail_args->name) == 0)
4465 if (mail_args->need_value && strcmpic(value, US"") == 0)
4468 switch(mail_args->value)
4470 /* Handle SIZE= by reading the value. We don't do the check till later,
4471 in order to be able to log the sender address on failure. */
4472 case ENV_MAIL_OPT_SIZE:
4473 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4475 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4477 message_size = (int)size;
4483 /* If this session was initiated with EHLO and accept_8bitmime is set,
4484 Exim will have indicated that it supports the BODY=8BITMIME option. In
4485 fact, it does not support this according to the RFCs, in that it does not
4486 take any special action for forwarding messages containing 8-bit
4487 characters. That is why accept_8bitmime is not the default setting, but
4488 some sites want the action that is provided. We recognize both "8BITMIME"
4489 and "7BIT" as body types, but take no action. */
4490 case ENV_MAIL_OPT_BODY:
4491 if (accept_8bitmime) {
4492 if (strcmpic(value, US"8BITMIME") == 0)
4494 else if (strcmpic(value, US"7BIT") == 0)
4499 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4500 US"invalid data for BODY");
4503 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4509 /* Handle the two DSN options, but only if configured to do so (which
4510 will have caused "DSN" to be given in the EHLO response). The code itself
4511 is included only if configured in at build time. */
4513 case ENV_MAIL_OPT_RET:
4514 if (fl.dsn_advertised)
4516 /* Check if RET has already been set */
4519 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4520 US"RET can be specified once only");
4523 dsn_ret = strcmpic(value, US"HDRS") == 0
4525 : strcmpic(value, US"FULL") == 0
4528 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4529 /* Check for invalid invalid value, and exit with error */
4532 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4533 US"Value for RET is invalid");
4538 case ENV_MAIL_OPT_ENVID:
4539 if (fl.dsn_advertised)
4541 /* Check if the dsn envid has been already set */
4544 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4545 US"ENVID can be specified once only");
4548 dsn_envid = string_copy(value);
4549 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4553 /* Handle the AUTH extension. If the value given is not "<>" and either
4554 the ACL says "yes" or there is no ACL but the sending host is
4555 authenticated, we set it up as the authenticated sender. However, if the
4556 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4557 the condition is met. The value of AUTH is an xtext, which means that +,
4558 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4560 case ENV_MAIL_OPT_AUTH:
4561 if (Ustrcmp(value, "<>") != 0)
4566 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4568 /* Put back terminator overrides for error message */
4571 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4572 US"invalid data for AUTH");
4575 GET_OPTION("acl_smtp_mailauth");
4576 if (!acl_smtp_mailauth)
4578 ignore_msg = US"client not authenticated";
4579 rc = sender_host_authenticated ? OK : FAIL;
4583 ignore_msg = US"rejected by ACL";
4584 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4585 &user_msg, &log_msg);
4591 if (authenticated_by == NULL ||
4592 authenticated_by->mail_auth_condition == NULL ||
4593 expand_check_condition(authenticated_by->mail_auth_condition,
4594 authenticated_by->name, US"authenticator"))
4595 break; /* Accept the AUTH */
4597 ignore_msg = US"server_mail_auth_condition failed";
4598 if (authenticated_id != NULL)
4599 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4600 ignore_msg, authenticated_id);
4605 authenticated_sender = NULL;
4606 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4607 value, host_and_ident(TRUE), ignore_msg);
4610 /* Should only get DEFER or ERROR here. Put back terminator
4611 overrides for error message */
4616 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4623 #ifndef DISABLE_PRDR
4624 case ENV_MAIL_OPT_PRDR:
4626 prdr_requested = TRUE;
4631 case ENV_MAIL_OPT_UTF8:
4632 if (!fl.smtputf8_advertised)
4634 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4635 US"SMTPUTF8 used when not advertised");
4639 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4640 message_smtputf8 = allow_utf8_domains = TRUE;
4641 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4643 int old_pool = store_pool;
4644 store_pool = POOL_PERM;
4645 received_protocol = string_sprintf("utf8%s", received_protocol);
4646 store_pool = old_pool;
4651 /* No valid option. Stick back the terminator characters and break
4652 the loop. Do the name-terminator second as extract_option sets
4653 value==name when it found no equal-sign.
4654 An error for a malformed address will occur. */
4655 case ENV_MAIL_OPT_NULL:
4663 /* Break out of for loop if switch() had bad argument or
4664 when start of the email address is reached */
4665 if (arg_error) break;
4668 /* If we have passed the threshold for rate limiting, apply the current
4669 delay, and update it for next time, provided this is a limited host. */
4671 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4672 verify_check_host(&smtp_ratelimit_hosts) == OK)
4674 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4675 smtp_delay_mail/1000.0);
4676 millisleep((int)smtp_delay_mail);
4677 smtp_delay_mail *= smtp_rlm_factor;
4678 if (smtp_delay_mail > (double)smtp_rlm_limit)
4679 smtp_delay_mail = (double)smtp_rlm_limit;
4682 /* Now extract the address, first applying any SMTP-time rewriting. The
4683 TRUE flag allows "<>" as a sender address. */
4685 raw_sender = rewrite_existflags & rewrite_smtp
4686 /* deconst ok as smtp_cmd_data was not const */
4687 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4688 global_rewrite_rules)
4692 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4697 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4701 sender_address = raw_sender;
4703 /* If there is a configured size limit for mail, check that this message
4704 doesn't exceed it. The check is postponed to this point so that the sender
4707 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4709 smtp_printf("552 Message size exceeds maximum permitted\r\n", SP_NO_MORE);
4710 log_write(L_size_reject,
4711 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4712 "message too big: size%s=%d max=%d",
4714 host_and_ident(TRUE),
4715 (message_size == INT_MAX)? ">" : "",
4717 thismessage_size_limit);
4718 sender_address = NULL;
4722 /* Check there is enough space on the disk unless configured not to.
4723 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4724 plus the current message - i.e. we accept the message only if it won't
4725 reduce the space below the threshold. Add 5000 to the size to allow for
4726 overheads such as the Received: line and storing of recipients, etc.
4727 By putting the check here, even when SIZE is not given, it allow VRFY
4728 and EXPN etc. to be used when space is short. */
4730 if (!receive_check_fs(
4731 smtp_check_spool_space && message_size >= 0
4732 ? message_size + 5000 : 0))
4734 smtp_printf("452 Space shortage, please try later\r\n", SP_NO_MORE);
4735 sender_address = NULL;
4739 /* If sender_address is unqualified, reject it, unless this is a locally
4740 generated message, or the sending host or net is permitted to send
4741 unqualified addresses - typically local machines behaving as MUAs -
4742 in which case just qualify the address. The flag is set above at the start
4743 of the SMTP connection. */
4745 if (!sender_domain && *sender_address)
4746 if (f.allow_unqualified_sender)
4748 sender_domain = Ustrlen(sender_address) + 1;
4749 /* deconst ok as sender_address was not const */
4750 sender_address = US rewrite_address_qualify(sender_address, FALSE);
4751 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4756 smtp_printf("501 %s: sender address must contain a domain\r\n", SP_NO_MORE,
4758 log_write(L_smtp_syntax_error,
4759 LOG_MAIN|LOG_REJECT,
4760 "unqualified sender rejected: <%s> %s%s",
4762 host_and_ident(TRUE),
4764 sender_address = NULL;
4768 /* Apply an ACL check if one is defined, before responding. Afterwards,
4769 when pipelining is not advertised, do another sync check in case the ACL
4770 delayed and the client started sending in the meantime. */
4772 GET_OPTION("acl_smtp_mail");
4775 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4776 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4782 if (rc == OK || rc == DISCARD)
4784 BOOL more = pipeline_response();
4787 smtp_printf("%s%s%s", more, US"250 OK",
4788 #ifndef DISABLE_PRDR
4789 prdr_requested ? US", PRDR Requested" : US"",
4796 #ifndef DISABLE_PRDR
4798 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4800 smtp_user_msg(US"250", user_msg);
4802 smtp_delay_rcpt = smtp_rlr_base;
4803 f.recipients_discarded = (rc == DISCARD);
4804 was_rej_mail = FALSE;
4808 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4809 sender_address = NULL;
4814 /* The RCPT command requires an address as an operand. There may be any
4815 number of RCPT commands, specifying multiple recipients. We build them all
4816 into a data structure. The start/end values given by parse_extract_address
4817 are not used, as we keep only the extracted address. */
4821 /* We got really to many recipients. A check against configured
4822 limits is done later */
4823 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
4824 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
4826 was_rcpt = fl.rcpt_in_progress = TRUE;
4828 /* There must be a sender address; if the sender was rejected and
4829 pipelining was advertised, we assume the client was pipelining, and do not
4830 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4831 get the same treatment. */
4833 if (!sender_address)
4835 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4837 smtp_printf("503 sender not yet given\r\n", SP_NO_MORE);
4838 was_rej_mail = TRUE;
4842 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4843 US"sender not yet given");
4844 was_rcpt = FALSE; /* Not a valid RCPT */
4850 /* Check for an operand */
4852 if (!smtp_cmd_data[0])
4854 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4855 US"RCPT must have an address operand");
4860 /* Set the DSN flags orcpt and dsn_flags from the session*/
4864 if (fl.esmtp) for(;;)
4866 uschar *name, *value;
4868 if (!extract_option(&name, &value))
4871 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4873 /* Check whether orcpt has been already set */
4876 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4877 US"ORCPT can be specified once only");
4880 orcpt = string_copy(value);
4881 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4884 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4886 /* Check if the notify flags have been already set */
4889 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4890 US"NOTIFY can be specified once only");
4893 if (strcmpic(value, US"NEVER") == 0)
4894 dsn_flags |= rf_notify_never;
4901 while (*pp != 0 && *pp != ',') pp++;
4902 if (*pp == ',') *pp++ = 0;
4903 if (strcmpic(p, US"SUCCESS") == 0)
4905 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4906 dsn_flags |= rf_notify_success;
4908 else if (strcmpic(p, US"FAILURE") == 0)
4910 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4911 dsn_flags |= rf_notify_failure;
4913 else if (strcmpic(p, US"DELAY") == 0)
4915 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4916 dsn_flags |= rf_notify_delay;
4920 /* Catch any strange values */
4921 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4922 US"Invalid value for NOTIFY parameter");
4927 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
4931 /* Unknown option. Stick back the terminator characters and break
4932 the loop. An error for a malformed address will occur. */
4936 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4943 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4944 as a recipient address */
4946 recipient = rewrite_existflags & rewrite_smtp
4947 /* deconst ok as smtp_cmd_data was not const */
4948 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4949 global_rewrite_rules)
4952 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4953 &recipient_domain, FALSE)))
4955 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4960 /* If the recipient address is unqualified, reject it, unless this is a
4961 locally generated message. However, unqualified addresses are permitted
4962 from a configured list of hosts and nets - typically when behaving as
4963 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4964 really. The flag is set at the start of the SMTP connection.
4966 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4967 assumed this meant "reserved local part", but the revision of RFC 821 and
4968 friends now makes it absolutely clear that it means *mailbox*. Consequently
4969 we must always qualify this address, regardless. */
4971 if (!recipient_domain)
4972 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4979 /* Check maximum allowed */
4981 if ( rcpt_count+1 < 0
4982 || rcpt_count > recipients_max_expanded && recipients_max_expanded > 0)
4984 if (recipients_max_reject)
4987 smtp_printf("552 too many recipients\r\n", SP_NO_MORE);
4989 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4990 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4995 smtp_printf("452 too many recipients\r\n", SP_NO_MORE);
4997 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4998 "temporarily rejected: sender=<%s> %s", sender_address,
4999 host_and_ident(TRUE));
5006 /* If we have passed the threshold for rate limiting, apply the current
5007 delay, and update it for next time, provided this is a limited host. */
5009 if (rcpt_count > smtp_rlr_threshold &&
5010 verify_check_host(&smtp_ratelimit_hosts) == OK)
5012 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5013 smtp_delay_rcpt/1000.0);
5014 millisleep((int)smtp_delay_rcpt);
5015 smtp_delay_rcpt *= smtp_rlr_factor;
5016 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5017 smtp_delay_rcpt = (double)smtp_rlr_limit;
5020 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5021 for them. Otherwise, check the access control list for this recipient. As
5022 there may be a delay in this, re-check for a synchronization error
5023 afterwards, unless pipelining was advertised. */
5025 if (f.recipients_discarded)
5029 GET_OPTION("acl_smtp_rcpt");
5030 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5032 && !f.smtp_in_pipelining_advertised && !check_sync())
5036 /* The ACL was happy */
5040 BOOL more = pipeline_response();
5043 smtp_user_msg(US"250", user_msg);
5045 smtp_printf("250 Accepted\r\n", more);
5046 receive_add_recipient(recipient, -1);
5048 /* Set the dsn flags in the recipients_list */
5049 recipients_list[recipients_count-1].orcpt = orcpt;
5050 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5052 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5053 recipients_list[recipients_count-1].orcpt,
5054 recipients_list[recipients_count-1].dsn_flags); */
5057 /* The recipient was discarded */
5059 else if (rc == DISCARD)
5062 smtp_user_msg(US"250", user_msg);
5064 smtp_printf("250 Accepted\r\n", SP_NO_MORE);
5067 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5068 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5069 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5070 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5071 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5074 /* Either the ACL failed the address, or it was deferred. */
5078 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5079 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5084 /* The DATA command is legal only if it follows successful MAIL FROM
5085 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5086 not counted as a protocol error if it follows RCPT (which must have been
5087 rejected if there are no recipients.) This function is complete when a
5088 valid DATA command is encountered.
5090 Note concerning the code used: RFC 2821 says this:
5092 - If there was no MAIL, or no RCPT, command, or all such commands
5093 were rejected, the server MAY return a "command out of sequence"
5094 (503) or "no valid recipients" (554) reply in response to the
5097 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5098 because it is the same whether pipelining is in use or not.
5100 If all the RCPT commands that precede DATA provoked the same error message
5101 (often indicating some kind of system error), it is helpful to include it
5102 with the DATA rejection (an idea suggested by Tony Finch). */
5109 if (chunking_state != CHUNKING_OFFERED)
5111 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5112 US"BDAT command used when CHUNKING not advertised");
5116 /* grab size, endmarker */
5118 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5120 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5121 US"missing size for BDAT command");
5124 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5125 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5126 chunking_data_left = chunking_datasize;
5127 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5128 (int)chunking_state, chunking_data_left);
5130 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
5139 f.bdat_readers_wanted = FALSE;
5141 DATA_BDAT: /* Common code for DATA and BDAT */
5142 #ifndef DISABLE_PIPE_CONNECT
5143 fl.pipe_connect_acceptable = FALSE;
5145 if (!discarded && recipients_count <= 0)
5147 if (fl.rcpt_smtp_response_same && rcpt_smtp_response)
5149 uschar *code = US"503";
5150 int len = Ustrlen(rcpt_smtp_response);
5151 smtp_respond(code, 3, SR_NOT_FINAL, US"All RCPT commands were rejected with "
5153 /* Responses from smtp_printf() will have \r\n on the end */
5154 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5155 rcpt_smtp_response[len-2] = 0;
5156 smtp_respond(code, 3, SR_NOT_FINAL, rcpt_smtp_response);
5158 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5159 smtp_printf("503 Valid RCPT command must precede %s\r\n", SP_NO_MORE,
5160 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5162 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5163 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5164 ? US"valid RCPT command must precede DATA"
5165 : US"valid RCPT command must precede BDAT");
5167 if (chunking_state > CHUNKING_OFFERED)
5169 bdat_push_receive_functions();
5175 if (toomany && recipients_max_reject)
5177 sender_address = NULL; /* This will allow a new MAIL without RSET */
5178 sender_address_unrewritten = NULL;
5179 smtp_printf("554 Too many recipients\r\n", SP_NO_MORE);
5181 if (chunking_state > CHUNKING_OFFERED)
5183 bdat_push_receive_functions();
5189 if (chunking_state > CHUNKING_OFFERED)
5190 rc = OK; /* There is no predata ACL or go-ahead output for BDAT */
5193 /* If there is a predata-ACL, re-check the synchronization afterwards,
5194 since the ACL may have delayed. To handle cutthrough delivery enforce a
5195 dummy call to get the DATA command sent. */
5197 GET_OPTION("acl_smtp_predata");
5198 if (!acl_smtp_predata && cutthrough.cctx.sock < 0)
5202 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5203 f.enable_dollar_recipients = TRUE;
5204 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5206 f.enable_dollar_recipients = FALSE;
5207 if (rc == OK && !check_sync())
5211 { /* Either the ACL failed the address, or it was deferred. */
5212 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5218 smtp_user_msg(US"354", user_msg);
5221 "354 Enter message, ending with \".\" on a line by itself\r\n", SP_NO_MORE);
5224 if (f.bdat_readers_wanted)
5225 bdat_push_receive_functions();
5228 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5229 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5230 US &on, sizeof(on));
5233 message_ended = END_NOTENDED; /* Indicate in middle of data */
5244 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5245 &start, &end, &recipient_domain, FALSE)))
5247 smtp_printf("501 %s\r\n", SP_NO_MORE, errmess);
5251 if (!recipient_domain)
5252 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5256 GET_OPTION("acl_smtp_vrfy");
5257 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5258 &user_msg, &log_msg)) != OK)
5259 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5263 address_item * addr = deliver_make_addr(address, FALSE);
5265 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5266 -1, -1, NULL, NULL, NULL))
5269 s = string_sprintf("250 <%s> is deliverable", address);
5273 s = (addr->user_message != NULL)?
5274 string_sprintf("451 <%s> %s", address, addr->user_message) :
5275 string_sprintf("451 Cannot resolve <%s> at this time", address);
5279 s = (addr->user_message != NULL)?
5280 string_sprintf("550 <%s> %s", address, addr->user_message) :
5281 string_sprintf("550 <%s> is not deliverable", address);
5282 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5283 smtp_cmd_argument, host_and_ident(TRUE));
5287 smtp_printf("%s\r\n", SP_NO_MORE, s);
5295 GET_OPTION("acl_smtp_expn");
5296 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5298 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5301 BOOL save_log_testing_mode = f.log_testing_mode;
5302 f.address_test_mode = f.log_testing_mode = TRUE;
5303 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5304 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5306 f.address_test_mode = FALSE;
5307 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5316 if (!fl.tls_advertised)
5318 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5319 US"STARTTLS command used when not advertised");
5323 /* Apply an ACL check if one is defined */
5325 GET_OPTION("acl_smtp_starttls");
5326 if ( acl_smtp_starttls
5327 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5328 &user_msg, &log_msg)) != OK
5331 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5335 /* RFC 2487 is not clear on when this command may be sent, though it
5336 does state that all information previously obtained from the client
5337 must be discarded if a TLS session is started. It seems reasonable to
5338 do an implied RSET when STARTTLS is received. */
5340 incomplete_transaction_log(US"STARTTLS");
5341 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5342 reset_point = smtp_reset(reset_point);
5344 cmd_list[CL_STLS].is_mail_cmd = FALSE;
5346 /* There's an attack where more data is read in past the STARTTLS command
5347 before TLS is negotiated, then assumed to be part of the secure session
5348 when used afterwards; we use segregated input buffers, so are not
5349 vulnerable, but we want to note when it happens and, for sheer paranoia,
5350 ensure that the buffer is "wiped".
5351 Pipelining sync checks will normally have protected us too, unless disabled
5352 by configuration. */
5357 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5358 if (tls_in.active.sock < 0)
5359 smtp_inend = smtp_inptr = smtp_inbuffer;
5360 /* and if TLS is already active, tls_server_start() should fail */
5363 /* There is nothing we value in the input buffer and if TLS is successfully
5364 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5365 fresh content into it. The buffer contains arbitrary content from an
5366 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5367 It seems safest to just wipe away the content rather than leave it as a
5368 target to jump to. */
5370 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5372 /* Attempt to start up a TLS session, and if successful, discard all
5373 knowledge that was obtained previously. At least, that's what the RFC says,
5374 and that's what happens by default. However, in order to work round YAEB,
5375 there is an option to remember the esmtp state. Sigh.
5377 We must allow for an extra EHLO command and an extra AUTH command after
5378 STARTTLS that don't add to the nonmail command count. */
5381 if ((rc = tls_server_start(&s)) == OK)
5383 if (!tls_remember_esmtp)
5384 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5385 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
5386 cmd_list[CL_AUTH].is_mail_cmd = TRUE;
5387 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
5388 if (sender_helo_name)
5390 sender_helo_name = NULL;
5391 host_build_sender_fullhost(); /* Rebuild */
5392 set_process_info("handling incoming TLS connection from %s",
5393 host_and_ident(FALSE));
5396 (sender_host_address ? protocols : protocols_local)
5398 ? pextend + (sender_host_authenticated ? pauthed : 0)
5400 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5403 sender_host_auth_pubname = sender_host_authenticated = NULL;
5404 authenticated_id = NULL;
5405 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5406 DEBUG(D_tls) debug_printf("TLS active\n");
5407 break; /* Successful STARTTLS */
5410 (void) smtp_log_tls_fail(s);
5412 /* Some local configuration problem was discovered before actually trying
5413 to do a TLS handshake; give a temporary error. */
5417 smtp_printf("454 TLS currently unavailable\r\n", SP_NO_MORE);
5421 /* Hard failure. Reject everything except QUIT or closed connection. One
5422 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5423 set, but we must still reject all incoming commands. Another is a handshake
5424 failure - and there may some encrypted data still in the pipe to us, which we
5425 see as garbage commands. */
5427 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5428 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5431 log_close_event(US"by EOF");
5432 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5436 /* It is perhaps arguable as to which exit ACL should be called here,
5437 but as it is probably a situation that almost never arises, it
5438 probably doesn't matter. We choose to call the real QUIT ACL, which in
5439 some sense is perhaps "right". */
5442 f.smtp_in_quit = TRUE;
5444 GET_OPTION("acl_smtp_quit");
5446 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5447 &log_msg)) == ERROR))
5448 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5451 smtp_respond(US"221", 3, SR_FINAL, user_msg);
5453 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
5454 log_close_event(US"by QUIT");
5459 smtp_printf("554 Security failure\r\n", SP_NO_MORE);
5462 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5467 /* The ACL for QUIT is provided for gathering statistical information or
5468 similar; it does not affect the response code, but it can supply a custom
5472 smtp_quit_handler(&user_msg, &log_msg);
5478 smtp_rset_handler();
5479 cancel_cutthrough_connection(TRUE, US"RSET received");
5480 reset_point = smtp_reset(reset_point);
5487 smtp_printf("250 OK\r\n", SP_NO_MORE);
5491 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5492 used, a check will be done for permitted hosts. Show STARTTLS only if not
5493 already in a TLS session and if it would be advertised in the EHLO
5498 smtp_printf("214-Commands supported:\r\n214", SP_MORE);
5499 smtp_printf(" AUTH", SP_MORE);
5501 if (tls_in.active.sock < 0 &&
5502 verify_check_host(&tls_advertise_hosts) != FAIL)
5503 smtp_printf(" STARTTLS", SP_MORE);
5505 smtp_printf(" HELO EHLO MAIL RCPT DATA BDAT", SP_MORE);
5506 smtp_printf(" NOOP QUIT RSET HELP", SP_MORE);
5507 if (acl_smtp_etrn) smtp_printf(" ETRN", SP_MORE);
5508 if (acl_smtp_expn) smtp_printf(" EXPN", SP_MORE);
5509 if (acl_smtp_vrfy) smtp_printf(" VRFY", SP_MORE);
5510 #ifndef DISABLE_WELLKNOWN
5511 if (verify_check_host(&wellknown_advertise_hosts) != FAIL)
5512 smtp_printf(" WELLKNOWN", SP_MORE);
5514 #ifdef EXPERIMENTAL_XCLIENT
5515 if (proxy_session || verify_check_host(&hosts_xclient) != FAIL)
5516 smtp_printf(" XCLIENT", SP_MORE);
5518 smtp_printf("\r\n", SP_NO_MORE);
5523 incomplete_transaction_log(US"connection lost");
5524 smtp_notquit_exit(US"connection-lost", US"421",
5525 US"%s lost input connection", smtp_active_hostname);
5527 /* Don't log by default unless in the middle of a message, as some mailers
5528 just drop the call rather than sending QUIT, and it clutters up the logs.
5531 if (sender_address || recipients_count > 0)
5532 log_write(L_lost_incoming_connection, LOG_MAIN,
5533 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5534 f.sender_host_unknown ? "EOF" : "disconnection",
5535 f.tcp_in_fastopen_logged
5538 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5540 host_and_ident(FALSE), smtp_read_error,
5541 string_timesince(&smtp_connection_start)
5545 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5546 smtp_get_connection_info(),
5547 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5549 string_timesince(&smtp_connection_start)
5560 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5561 US"ETRN is not permitted inside a transaction");
5565 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5566 host_and_ident(FALSE));
5568 GET_OPTION("acl_smtp_etrn");
5569 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5570 &user_msg, &log_msg)) != OK)
5572 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5576 /* Compute the serialization key for this command. */
5578 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5580 /* If a command has been specified for running as a result of ETRN, we
5581 permit any argument to ETRN. If not, only the # standard form is permitted,
5582 since that is strictly the only kind of ETRN that can be implemented
5583 according to the RFC. */
5585 GET_OPTION("smtp_etrn_command");
5586 if (smtp_etrn_command)
5590 etrn_command = smtp_etrn_command;
5591 deliver_domain = smtp_cmd_data;
5592 rc = transport_set_up_command(&argv, smtp_etrn_command, TSUC_EXPAND_ARGS, 0, NULL,
5593 US"ETRN processing", &error);
5594 deliver_domain = NULL;
5597 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5599 smtp_printf("458 Internal failure\r\n", SP_NO_MORE);
5604 /* Else set up to call Exim with the -R option. */
5608 if (*smtp_cmd_data++ != '#')
5610 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5611 US"argument must begin with #");
5614 etrn_command = US"exim -R";
5615 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5616 *queue_name ? 4 : 2,
5617 US"-R", smtp_cmd_data,
5618 US"-MCG", queue_name);
5621 /* If we are host-testing, don't actually do anything. */
5627 debug_printf("ETRN command is: %s\n", etrn_command);
5628 debug_printf("ETRN command execution skipped\n");
5630 if (user_msg == NULL) smtp_printf("250 OK\r\n", SP_NO_MORE);
5631 else smtp_user_msg(US"250", user_msg);
5636 /* If ETRN queue runs are to be serialized, check the database to
5637 ensure one isn't already running. */
5639 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5641 smtp_printf("458 Already processing %s\r\n", SP_NO_MORE, smtp_cmd_data);
5645 /* Fork a child process and run the command. We don't want to have to
5646 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5647 forking. It should be set that way anyway for external incoming SMTP,
5648 but we save and restore to be tidy. If serialization is required, we
5649 actually run the command in yet another process, so we can wait for it
5650 to complete and then remove the serialization lock. */
5652 oldsignal = signal(SIGCHLD, SIG_IGN);
5654 if ((pid = exim_fork(US"etrn-command")) == 0)
5656 smtp_input = FALSE; /* This process is not associated with the */
5657 (void)fclose(smtp_in); /* SMTP call any more. */
5658 (void)fclose(smtp_out);
5660 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5662 /* If not serializing, do the exec right away. Otherwise, fork down
5663 into another process. */
5665 if ( !smtp_etrn_serialize
5666 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5668 DEBUG(D_exec) debug_print_argv(argv);
5669 exim_nullstd(); /* Ensure std{in,out,err} exist */
5670 /* argv[0] should be untainted, from child_exec_exim() */
5671 execv(CS argv[0], (char *const *)argv);
5672 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5673 etrn_command, strerror(errno));
5674 _exit(EXIT_FAILURE); /* paranoia */
5677 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5678 is, we are in the first subprocess, after forking again. All we can do
5679 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5680 complete, before removing the serialization. */
5683 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5684 "failed: %s", strerror(errno));
5688 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5690 (void)wait(&status);
5691 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5695 enq_end(etrn_serialize_key);
5696 exim_underbar_exit(EXIT_SUCCESS);
5699 /* Back in the top level SMTP process. Check that we started a subprocess
5700 and restore the signal state. */
5704 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5706 smtp_printf("458 Unable to fork process\r\n", SP_NO_MORE);
5707 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5711 smtp_printf("250 OK\r\n", SP_NO_MORE);
5713 smtp_user_msg(US"250", user_msg);
5715 signal(SIGCHLD, oldsignal);
5720 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5721 US"unexpected argument data");
5725 /* This currently happens only for NULLs, but could be extended. */
5728 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5729 US"NUL character(s) present (shown as '?')");
5730 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5738 unsigned nchars = 150;
5739 uschar * buf = receive_getbuf(&nchars); /* destructive read */
5741 incomplete_transaction_log(US"sync failure");
5742 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5743 "(next input sent too soon: pipelining was%s advertised): "
5744 "rejected \"%s\" %s next input=\"%s\" (%u bytes)",
5745 f.smtp_in_pipelining_advertised ? "" : " not",
5746 smtp_cmd_buffer, host_and_ident(TRUE),
5747 string_printing(buf), nchars);
5748 smtp_notquit_exit(US"synchronization-error", US"554",
5749 US"SMTP synchronization error");
5750 done = 1; /* Pretend eof - drops connection */
5755 case TOO_MANY_NONMAIL_CMD:
5756 s = smtp_cmd_buffer;
5758 incomplete_transaction_log(US"too many non-mail commands");
5759 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5760 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5761 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5762 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5763 done = 1; /* Pretend eof - drops connection */
5766 #ifdef SUPPORT_PROXY
5767 case PROXY_FAIL_IGNORE_CMD:
5768 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", SP_NO_MORE);
5773 if (unknown_command_count++ >= smtp_max_unknown_commands)
5775 log_write(L_smtp_syntax_error, LOG_MAIN,
5776 "SMTP syntax error in \"%s\" %s %s",
5777 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5778 US"unrecognized command");
5779 incomplete_transaction_log(US"unrecognized command");
5780 smtp_notquit_exit(US"bad-commands", US"500",
5781 US"Too many unrecognized commands");
5783 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5784 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5785 string_printing(smtp_cmd_buffer));
5788 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5789 US"unrecognized command");
5793 /* This label is used by goto's inside loops that want to break out to
5794 the end of the command-processing loop. */
5797 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5798 last_was_rcpt = was_rcpt; /* protocol error handling */
5801 return done - 2; /* Convert yield values */
5807 authres_smtpauth(gstring * g)
5809 if (!sender_host_authenticated)
5812 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5814 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
5815 g = authenticated_id
5816 ? string_append(g, 2, US") x509.auth=", authenticated_id)
5817 : string_cat(g, US") reason=x509.auth");
5819 g = authenticated_id
5820 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
5821 : string_cat(g, US", no id saved)");
5823 if (authenticated_sender)
5824 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5832 /* End of smtp_in.c */