1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) The Exim Maintainers 2020 - 2024 */
6 /* Copyright (c) University of Cambridge 1995 - 2018 */
7 /* See the file NOTICE for conditions of use and distribution. */
8 /* SPDX-License-Identifier: GPL-2.0-or-later */
10 /* Functions for handling an incoming SMTP call. */
17 /* Initialize for TCP wrappers if so configured. It appears that the macro
18 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
19 including that header, and restore its value afterwards. */
21 #ifdef USE_TCP_WRAPPERS
24 #define EXIM_HAVE_IPV6
30 #define HAVE_IPV6 TRUE
33 int allow_severity = LOG_INFO;
34 int deny_severity = LOG_NOTICE;
35 uschar *tcp_wrappers_name;
39 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
40 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
41 commands that accept arguments, and this in particular applies to AUTH, where
42 the data can be quite long. More recently this value was 2048 in Exim;
43 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
44 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
45 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
46 we need room to handle large base64-encoded AUTHs for GSSAPI.
49 #define SMTP_CMD_BUFFER_SIZE 16384
51 /* Size of buffer for reading SMTP incoming packets */
53 #define IN_BUFFER_SIZE 8192
55 /* Structure for SMTP command list */
62 short int is_mail_cmd;
65 /* Codes for identifying commands. We order them so that those that come first
66 are those for which synchronization is always required. Checking this can help
70 /* These commands are required to be synchronized, i.e. to be the last in a
71 block of commands when pipelining. */
73 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
74 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
75 ETRN_CMD, /* This by analogy with TURN from the RFC */
76 STARTTLS_CMD, /* Required by the STARTTLS RFC */
77 TLS_AUTH_CMD, /* auto-command at start of SSL */
78 #ifdef EXPERIMENTAL_XCLIENT
79 XCLIENT_CMD, /* per xlexkiro implementation */
82 /* This is a dummy to identify the non-sync commands when pipelining */
84 NON_SYNC_CMD_PIPELINING,
86 /* These commands need not be synchronized when pipelining */
88 MAIL_CMD, RCPT_CMD, RSET_CMD,
89 #ifndef DISABLE_WELLKNOWN
93 /* This is a dummy to identify the non-sync commands when not pipelining */
95 NON_SYNC_CMD_NON_PIPELINING,
97 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
98 processed the message is sent using a series of BDAT commands"
99 implies that BDAT should be synchronized. However, we see Google, at least,
100 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
101 processing of the RCPT response(s). We shall do the same, and not require
102 synch for BDAT. Worse, as the chunk may (very likely will) follow the
103 command-header in the same packet we cannot do the usual "is there any
104 follow-on data after the command line" even for non-pipeline mode.
105 So we'll need an explicit check after reading the expected chunk amount
106 when non-pipe, before sending the ACK. */
110 /* I have been unable to find a statement about the use of pipelining
111 with AUTH, so to be on the safe side it is here, though I kind of feel
112 it should be up there with the synchronized commands. */
116 /* I'm not sure about these, but I don't think they matter. */
121 PROXY_FAIL_IGNORE_CMD,
124 /* These are specials that don't correspond to actual commands */
126 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
131 /* This is a convenience macro for adding the identity of an SMTP command
132 to the circular buffer that holds a list of the last n received. */
135 smtp_connection_had[smtp_ch_index++] = n; \
136 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
139 /*************************************************
140 * Local static variables *
141 *************************************************/
144 BOOL auth_advertised :1;
146 BOOL tls_advertised :1;
148 BOOL dsn_advertised :1;
150 BOOL helo_verify_required :1;
153 BOOL helo_accept_junk :1;
154 #ifndef DISABLE_PIPE_CONNECT
155 BOOL pipe_connect_acceptable :1;
157 BOOL rcpt_smtp_response_same :1;
158 BOOL rcpt_in_progress :1;
159 BOOL smtp_exit_function_called :1;
161 BOOL smtputf8_advertised :1;
164 .helo_verify_required = FALSE,
165 .helo_verify = FALSE,
166 .smtp_exit_function_called = FALSE,
169 static auth_instance *authenticated_by;
170 static int count_nonmail;
171 static int nonmail_command_count;
172 static int synprot_error_count;
173 static int unknown_command_count;
174 static int sync_cmd_limit;
175 static int smtp_write_error = 0;
177 static uschar *rcpt_smtp_response;
178 static uschar *smtp_data_buffer;
179 static uschar *smtp_cmd_data;
181 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
182 final fields of all except AUTH are forced TRUE at the start of a new message
183 setup, to allow one of each between messages that is not counted as a nonmail
184 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
185 allow a new EHLO after starting up TLS.
187 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
188 counted. However, the flag is changed when AUTH is received, so that multiple
189 failing AUTHs will eventually hit the limit. After a successful AUTH, another
190 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
191 forced TRUE, to allow for the re-authentication that can happen at that point.
193 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
194 count of non-mail commands and possibly provoke an error.
196 tls_auth is a pseudo-command, never expected in input. It is activated
197 on TLS startup and looks for a tls authenticator. */
208 #ifdef EXPERIMENTAL_XCLIENT
213 static smtp_cmd_list cmd_list[] = {
214 /* name len cmd has_arg is_mail_cmd */
216 [CL_RSET] = { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
217 [CL_HELO] = { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
218 [CL_EHLO] = { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
219 [CL_AUTH] = { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
221 [CL_STLS] = { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
222 [CL_TLAU] = { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
224 #ifdef EXPERIMENTAL_XCLIENT
225 [CL_XCLI] = { "xclient", sizeof("xclient")-1, XCLIENT_CMD, TRUE, FALSE },
228 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
229 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
230 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
231 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
232 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
233 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
234 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
235 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
236 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
237 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE },
238 #ifndef DISABLE_WELLKNOWN
239 { "wellknown", sizeof("wellknown")-1, WELLKNOWN_CMD, TRUE, FALSE },
243 /* This list of names is used for performing the smtp_no_mail logging action. */
245 uschar * smtp_names[] =
247 [SCH_NONE] = US"NONE",
248 [SCH_AUTH] = US"AUTH",
249 [SCH_DATA] = US"DATA",
250 [SCH_BDAT] = US"BDAT",
251 [SCH_EHLO] = US"EHLO",
252 [SCH_ETRN] = US"ETRN",
253 [SCH_EXPN] = US"EXPN",
254 [SCH_HELO] = US"HELO",
255 [SCH_HELP] = US"HELP",
256 [SCH_MAIL] = US"MAIL",
257 [SCH_NOOP] = US"NOOP",
258 [SCH_QUIT] = US"QUIT",
259 [SCH_RCPT] = US"RCPT",
260 [SCH_RSET] = US"RSET",
261 [SCH_STARTTLS] = US"STARTTLS",
262 [SCH_VRFY] = US"VRFY",
263 #ifndef DISABLE_WELLKNOWN
264 [SCH_WELLKNOWN] = US"WELLKNOWN",
266 #ifdef EXPERIMENTAL_XCLIENT
267 [SCH_XCLIENT] = US"XCLIENT",
271 static uschar *protocols_local[] = {
272 US"local-smtp", /* HELO */
273 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
274 US"local-esmtp", /* EHLO */
275 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
276 US"local-esmtpa", /* EHLO->AUTH */
277 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
279 static uschar *protocols[] = {
281 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
282 US"esmtp", /* EHLO */
283 US"esmtps", /* EHLO->STARTTLS->EHLO */
284 US"esmtpa", /* EHLO->AUTH */
285 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
290 #define pcrpted 1 /* added to pextend or pnormal */
291 #define pauthed 2 /* added to pextend */
293 /* Sanity check and validate optional args to MAIL FROM: envelope */
296 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
300 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
306 uschar * name; /* option requested during MAIL cmd */
307 int value; /* enum type */
308 BOOL need_value; /* TRUE requires value (name=value pair format)
309 FALSE is a singleton */
311 static env_mail_type_t env_mail_type_list[] = {
312 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
313 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
314 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
316 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
318 { US"RET", ENV_MAIL_OPT_RET, TRUE },
319 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
321 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
323 /* keep this the last entry */
324 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
327 /* When reading SMTP from a remote host, we have to use our own versions of the
328 C input-reading functions, in order to be able to flush the SMTP output only
329 when about to read more data from the socket. This is the only way to get
330 optimal performance when the client is using pipelining. Flushing for every
331 command causes a separate packet and reply packet each time; saving all the
332 responses up (when pipelining) combines them into one packet and one response.
334 For simplicity, these functions are used for *all* SMTP input, not only when
335 receiving over a socket. However, after setting up a secure socket (SSL), input
336 is read via the OpenSSL library, and another set of functions is used instead
339 These functions are set in the receive_getc etc. variables and called with the
340 same interface as the C functions. However, since there can only ever be
341 one incoming SMTP call, we just use a single buffer and flags. There is no need
342 to implement a complicated private FILE-like structure.*/
344 static uschar *smtp_inbuffer;
345 static uschar *smtp_inptr;
346 static uschar *smtp_inend;
347 static int smtp_had_eof;
348 static int smtp_had_error;
351 /* forward declarations */
352 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
353 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
354 static void smtp_quit_handler(uschar **, uschar **);
355 static void smtp_rset_handler(void);
357 /*************************************************
358 * Log incomplete transactions *
359 *************************************************/
361 /* This function is called after a transaction has been aborted by RSET, QUIT,
362 connection drops or other errors. It logs the envelope information received
363 so far in order to preserve address verification attempts.
365 Argument: string to indicate what aborted the transaction
370 incomplete_transaction_log(uschar * what)
372 if (!sender_address /* No transaction in progress */
373 || !LOGGING(smtp_incomplete_transaction))
376 /* Build list of recipients for logging */
378 if (recipients_count > 0)
380 raw_recipients = store_get(recipients_count * sizeof(uschar *), GET_UNTAINTED);
381 for (int i = 0; i < recipients_count; i++)
382 raw_recipients[i] = recipients_list[i].address;
383 raw_recipients_count = recipients_count;
386 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
387 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
393 log_close_event(const uschar * reason)
395 log_write(L_smtp_connection, LOG_MAIN, "%s D=%s closed %s",
396 smtp_get_connection_info(), string_timesince(&smtp_connection_start), reason);
401 smtp_command_timeout_exit(void)
403 log_write(L_lost_incoming_connection,
404 LOG_MAIN, "SMTP command timeout on%s connection from %s D=%s",
405 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE),
406 string_timesince(&smtp_connection_start));
407 if (smtp_batched_input)
408 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
409 smtp_notquit_exit(US"command-timeout", US"421",
410 US"%s: SMTP command timeout - closing connection",
411 smtp_active_hostname);
412 exim_exit(EXIT_FAILURE);
416 smtp_command_sigterm_exit(void)
418 log_close_event(US"after SIGTERM");
419 if (smtp_batched_input)
420 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
421 smtp_notquit_exit(US"signal-exit", US"421",
422 US"%s: Service not available - closing connection", smtp_active_hostname);
423 exim_exit(EXIT_FAILURE);
427 smtp_data_timeout_exit(void)
429 log_write(L_lost_incoming_connection, LOG_MAIN,
430 "SMTP data timeout (message abandoned) on connection from %s F=<%s> D=%s",
431 sender_fullhost ? sender_fullhost : US"local process", sender_address,
432 string_timesince(&smtp_connection_start));
433 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
434 /* Does not return */
438 smtp_data_sigint_exit(void)
440 log_close_event(had_data_sigint == SIGTERM ? US"SIGTERM":US"SIGINT");
441 receive_bomb_out(US"signal-exit",
442 US"Service not available - SIGTERM or SIGINT received");
443 /* Does not return */
447 /******************************************************************************/
448 /* SMTP input buffer handling. Most of these are similar to stdio routines. */
453 /* Set up the buffer for inputting using direct read() calls, and arrange to
454 call the local functions instead of the standard C ones. Place a NUL at the
455 end of the buffer to safety-stop C-string reads from it. */
457 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
458 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
459 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
461 smtp_inptr = smtp_inend = smtp_inbuffer;
462 smtp_had_eof = smtp_had_error = 0;
468 /* Feed received message data to the dkim module */
469 /*XXX maybe a global dkim_info? */
471 smtp_verify_feed(const uschar * s, unsigned n)
473 static misc_module_info * dkim_mi = NULL;
474 typedef void (*fn_t)(const uschar *, int);
476 if (!dkim_mi && !(dkim_mi = misc_mod_findonly(US"dkim")))
479 (((fn_t *) dkim_mi->functions)[DKIM_VERIFY_FEED]) (s, n);
484 /* Refill the buffer, and notify DKIM verification code.
485 Return false for error or EOF.
489 smtp_refill(unsigned lim)
493 if (!smtp_out) return FALSE;
495 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
497 /* Limit amount read, so non-message data is not fed to DKIM.
498 Take care to not touch the safety NUL at the end of the buffer. */
500 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
502 if (smtp_receive_timeout > 0) ALARM_CLR(0);
505 /* Must put the error text in fixed store, because this might be during
506 header reading, where it releases unused store above the header. */
509 if (had_command_timeout) /* set by signal handler */
510 smtp_command_timeout_exit(); /* does not return */
511 if (had_command_sigterm)
512 smtp_command_sigterm_exit();
513 if (had_data_timeout)
514 smtp_data_timeout_exit();
516 smtp_data_sigint_exit();
518 smtp_had_error = save_errno;
519 smtp_read_error = string_copy_perm(
520 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
527 smtp_verify_feed(smtp_inbuffer, rc);
529 smtp_inend = smtp_inbuffer + rc;
530 smtp_inptr = smtp_inbuffer;
535 /* Check if there is buffered data */
540 return smtp_inptr < smtp_inend;
543 /* SMTP version of getc()
545 This gets the next byte from the SMTP input buffer. If the buffer is empty,
546 it flushes the output, and refills the buffer, with a timeout. The signal
547 handler is set appropriately by the calling function. This function is not used
548 after a connection has negotiated itself into an TLS/SSL state.
550 Arguments: lim Maximum amount to read/buffer
551 Returns: the next character or EOF
555 smtp_getc(unsigned lim)
557 if (!smtp_hasc() && !smtp_refill(lim)) return EOF;
558 return *smtp_inptr++;
561 /* Get many bytes, refilling buffer if needed */
564 smtp_getbuf(unsigned * len)
569 if (!smtp_hasc() && !smtp_refill(*len))
570 { *len = 0; return NULL; }
572 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
579 /* Copy buffered data to the dkim feed.
580 Called, unless TLS, just before starting to read message headers. */
583 smtp_get_cache(unsigned lim)
586 int n = smtp_inend - smtp_inptr;
590 smtp_verify_feed(smtp_inptr, n);
595 /* SMTP version of ungetc()
596 Puts a character back in the input buffer. Only ever called once.
601 Returns: the character
607 if (smtp_inptr <= smtp_inbuffer) /* NB: NOT smtp_hasc() ! */
608 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "buffer underflow in smtp_ungetc");
615 /* SMTP version of feof()
616 Tests for a previous EOF
619 Returns: non-zero if the eof flag is set
629 /* SMTP version of ferror()
630 Tests for a previous read error, and returns with errno
631 restored to what it was when the error was detected.
634 Returns: non-zero if the error flag is set
640 errno = smtp_had_error;
641 return smtp_had_error;
645 /* Check if a getc will block or not */
648 smtp_could_getc(void)
652 struct timeval tzero = {.tv_sec = 0, .tv_usec = 0};
654 if (smtp_inptr < smtp_inend)
657 fd = fileno(smtp_in);
660 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
662 if (rc <= 0) return FALSE; /* Not ready to read */
663 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
664 if (rc < 0) return FALSE; /* End of file or error */
671 /******************************************************************************/
672 /*************************************************
673 * Recheck synchronization *
674 *************************************************/
676 /* Synchronization checks can never be perfect because a packet may be on its
677 way but not arrived when the check is done. Normally, the checks happen when
678 commands are read: Exim ensures that there is no more input in the input buffer.
679 In normal cases, the response to the command will be fast, and there is no
682 However, for some commands an ACL is run, and that can include delays. In those
683 cases, it is useful to do another check on the input just before sending the
684 response. This also applies at the start of a connection. This function does
685 that check by means of the select() function, as long as the facility is not
686 disabled or inappropriate. A failure of select() is ignored.
688 When there is unwanted input, we read it so that it appears in the log of the
692 Returns: TRUE if all is well; FALSE if there is input pending
696 wouldblock_reading(void)
699 if (tls_in.active.sock >= 0)
700 return !tls_could_getc();
703 return !smtp_could_getc();
709 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
712 return wouldblock_reading();
716 /******************************************************************************/
717 /* Variants of the smtp_* input handling functions for use in CHUNKING mode */
719 /* Forward declarations */
720 static inline void bdat_push_receive_functions(void);
721 static inline void bdat_pop_receive_functions(void);
724 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
725 previous BDAT chunk and getting new ones when we run out. Uses the
726 underlying smtp_getc or tls_getc both for that and for getting the
727 (buffered) data byte. EOD signals (an expected) no further data.
728 ERR signals a protocol error, and EOF a closed input stream.
730 Called from read_bdat_smtp() in receive.c for the message body, but also
731 by the headers read loop in receive_msg(); manipulates chunking_state
732 to handle the BDAT command/response.
733 Placed here due to the correlation with the above smtp_getc(), which it wraps,
734 and also by the need to do smtp command/response handling.
736 Arguments: lim (ignored)
737 Returns: the next character or ERR, EOD or EOF
741 bdat_getc(unsigned lim)
743 uschar * user_msg = NULL;
747 misc_module_info * dkim_info = misc_mod_findonly(US"dkim");
748 typedef void (*dkim_pause_t)(BOOL);
749 dkim_pause_t dkim_pause;
751 dkim_pause = dkim_info
752 ? ((dkim_pause_t *) dkim_info->functions)[DKIM_VERIFY_PAUSE] : NULL;
758 if (chunking_data_left > 0)
759 return lwr_receive_getc(chunking_data_left--);
761 bdat_pop_receive_functions();
763 if (dkim_pause) dkim_pause(TRUE);
766 /* Unless PIPELINING was offered, there should be no next command
767 until after we ack that chunk */
769 if (!f.smtp_in_pipelining_advertised && !check_sync())
771 unsigned n = smtp_inend - smtp_inptr;
774 incomplete_transaction_log(US"sync failure");
775 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
776 "(next input sent too soon: pipelining was not advertised): "
777 "rejected \"%s\" %s next input=\"%s\"%s",
778 smtp_cmd_buffer, host_and_ident(TRUE),
779 string_printing(string_copyn(smtp_inptr, n)),
780 smtp_inend - smtp_inptr > n ? "..." : "");
781 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
782 US"SMTP synchronization error");
783 goto repeat_until_rset;
786 /* If not the last, ack the received chunk. The last response is delayed
787 until after the data ACL decides on it */
789 if (chunking_state == CHUNKING_LAST)
792 smtp_verify_feed(NULL, 0); /* notify EOD */
797 smtp_printf("250 %u byte chunk received\r\n", SP_NO_MORE, chunking_datasize);
798 chunking_state = CHUNKING_OFFERED;
799 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
801 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
802 QUIT, RSET or NOOP but handling them seems obvious */
805 switch(smtp_read_command(TRUE, 1))
808 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
809 US"only BDAT permissible after non-LAST BDAT");
812 switch(smtp_read_command(TRUE, 1))
814 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
815 case EOF_CMD: return EOF;
816 case RSET_CMD: smtp_rset_handler(); return ERR;
817 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
818 US"only RSET accepted now") > 0)
820 goto repeat_until_rset;
824 smtp_quit_handler(&user_msg, &log_msg);
835 smtp_printf("250 OK\r\n", SP_NO_MORE);
842 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
844 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
845 US"missing size for BDAT command");
848 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
849 ? CHUNKING_LAST : CHUNKING_ACTIVE;
850 chunking_data_left = chunking_datasize;
851 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
852 (int)chunking_state, chunking_data_left);
854 if (chunking_datasize == 0)
855 if (chunking_state == CHUNKING_LAST)
859 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
860 US"zero size for BDAT command");
861 goto repeat_until_rset;
864 bdat_push_receive_functions();
866 if (dkim_pause) dkim_pause(FALSE);
868 break; /* to top of main loop */
877 if (chunking_data_left > 0)
878 return lwr_receive_hasc();
883 bdat_getbuf(unsigned * len)
887 if (chunking_data_left <= 0)
888 { *len = 0; return NULL; }
890 if (*len > chunking_data_left) *len = chunking_data_left;
891 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
892 chunking_data_left -= *len;
897 bdat_flush_data(void)
899 while (chunking_data_left)
901 unsigned n = chunking_data_left;
902 if (!bdat_getbuf(&n)) break;
905 bdat_pop_receive_functions();
906 chunking_state = CHUNKING_OFFERED;
907 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
912 bdat_push_receive_functions(void)
914 /* push the current receive_* function on the "stack", and
915 replace them by bdat_getc(), which in turn will use the lwr_receive_*
916 functions to do the dirty work. */
917 if (!lwr_receive_getc)
919 lwr_receive_getc = receive_getc;
920 lwr_receive_getbuf = receive_getbuf;
921 lwr_receive_hasc = receive_hasc;
922 lwr_receive_ungetc = receive_ungetc;
926 DEBUG(D_receive) debug_printf("chunking double-push receive functions\n");
929 receive_getc = bdat_getc;
930 receive_getbuf = bdat_getbuf;
931 receive_hasc = bdat_hasc;
932 receive_ungetc = bdat_ungetc;
936 bdat_pop_receive_functions(void)
938 if (!lwr_receive_getc)
940 DEBUG(D_receive) debug_printf("chunking double-pop receive functions\n");
943 receive_getc = lwr_receive_getc;
944 receive_getbuf = lwr_receive_getbuf;
945 receive_hasc = lwr_receive_hasc;
946 receive_ungetc = lwr_receive_ungetc;
948 lwr_receive_getc = NULL;
949 lwr_receive_getbuf = NULL;
950 lwr_receive_hasc = NULL;
951 lwr_receive_ungetc = NULL;
957 chunking_data_left++;
958 bdat_push_receive_functions(); /* we're not done yet, calling push is safe, because it checks the state before pushing anything */
959 return lwr_receive_ungetc(ch);
964 /******************************************************************************/
966 /*************************************************
967 * Write formatted string to SMTP channel *
968 *************************************************/
970 /* This is a separate function so that we don't have to repeat everything for
971 TLS support or debugging. It is global so that the daemon and the
972 authentication functions can use it. It does not return any error indication,
973 because major problems such as dropped connections won't show up till an output
974 flush for non-TLS connections. The smtp_fflush() function is available for
975 checking that: for convenience, TLS output errors are remembered here so that
976 they are also picked up later by smtp_fflush().
978 This function is exposed to the local_scan API; do not change the signature.
982 more further data expected
983 ... optional arguments
989 smtp_printf(const char *format, BOOL more, ...)
994 smtp_vprintf(format, more, ap);
998 /* This is split off so that verify.c:respond_printf() can, in effect, call
999 smtp_printf(), bearing in mind that in C a vararg function can't directly
1000 call another vararg function, only a function which accepts a va_list.
1002 This function is exposed to the local_scan API; do not change the signature.
1004 /*XXX consider passing caller-info in, for string_vformat-onward */
1007 smtp_vprintf(const char *format, BOOL more, va_list ap)
1009 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
1012 /* Use taint-unchecked routines for writing into big_buffer, trusting
1013 that we'll never expand it. */
1015 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
1016 string_from_gstring(&gs);
1018 DEBUG(D_receive) for (const uschar * t, * s = gs.s;
1019 s && (t = Ustrchr(s, '\r'));
1020 s = t + 2) /* \r\n */
1021 debug_printf("%s %.*s\n",
1022 s == gs.s ? "SMTP>>" : " ",
1027 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
1028 smtp_closedown(US"Unexpected error");
1029 exim_exit(EXIT_FAILURE);
1032 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
1033 have had the same. Note: this code is also present in smtp_respond(). It would
1034 be tidier to have it only in one place, but when it was added, it was easier to
1035 do it that way, so as not to have to mess with the code for the RCPT command,
1036 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
1038 if (fl.rcpt_in_progress)
1040 if (!rcpt_smtp_response)
1041 rcpt_smtp_response = string_copy(big_buffer);
1042 else if (fl.rcpt_smtp_response_same &&
1043 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
1044 fl.rcpt_smtp_response_same = FALSE;
1045 fl.rcpt_in_progress = FALSE;
1048 /* Now write the string */
1052 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
1054 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
1056 smtp_write_error = -1;
1061 /*************************************************
1062 * Flush SMTP out and check for error *
1063 *************************************************/
1065 /* This function isn't currently used within Exim (it detects errors when it
1066 tries to read the next SMTP input), but is available for use in local_scan().
1067 It flushes the output and checks for errors.
1070 Returns: 0 for no error; -1 after an error
1076 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
1080 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
1082 (fflush(smtp_out) != 0)
1084 smtp_write_error = -1;
1086 return smtp_write_error;
1091 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
1092 a reponse with the one following. */
1095 pipeline_response(void)
1097 if ( !smtp_enforce_sync || !sender_host_address
1098 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
1101 if (wouldblock_reading()) return FALSE;
1102 f.smtp_in_pipelining_used = TRUE;
1107 #ifndef DISABLE_PIPE_CONNECT
1109 pipeline_connect_sends(void)
1111 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
1114 if (wouldblock_reading()) return FALSE;
1115 f.smtp_in_early_pipe_used = TRUE;
1120 /*************************************************
1121 * SMTP command read timeout *
1122 *************************************************/
1124 /* Signal handler for timing out incoming SMTP commands. This attempts to
1127 Argument: signal number (SIGALRM)
1132 command_timeout_handler(int sig)
1134 had_command_timeout = sig;
1139 /*************************************************
1140 * SIGTERM received *
1141 *************************************************/
1143 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1145 Argument: signal number (SIGTERM)
1150 command_sigterm_handler(int sig)
1152 had_command_sigterm = sig;
1158 /*************************************************
1159 * Read one command line *
1160 *************************************************/
1162 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1163 There are sites that don't do this, and in any case internal SMTP probably
1164 should check only for LF. Consequently, we check here for LF only. The line
1165 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1166 an unknown command. The command is read into the global smtp_cmd_buffer so that
1167 it is available via $smtp_command.
1169 The character reading routine sets up a timeout for each block actually read
1170 from the input (which may contain more than one command). We set up a special
1171 signal handler that closes down the session on a timeout. Control does not
1172 return when it runs.
1175 check_sync if TRUE, check synchronization rules if global option is TRUE
1176 buffer_lim maximum to buffer in lower layer
1178 Returns: a code identifying the command (enumerated above)
1182 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1186 BOOL hadnull = FALSE;
1188 had_command_timeout = 0;
1189 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1191 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1193 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1195 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1203 smtp_cmd_buffer[ptr++] = c;
1206 receive_linecount++; /* For BSMTP errors */
1207 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1209 /* If hit end of file, return pseudo EOF command. Whether we have a
1210 part-line already read doesn't matter, since this is an error state. */
1212 if (c == EOF) return EOF_CMD;
1214 /* Remove any CR and white space at the end of the line, and terminate the
1217 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1218 smtp_cmd_buffer[ptr] = 0;
1220 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1222 /* NULLs are not allowed in SMTP commands */
1224 if (hadnull) return BADCHAR_CMD;
1226 /* Scan command list and return identity, having set the data pointer
1227 to the start of the actual data characters. Check for SMTP synchronization
1230 for (smtp_cmd_list * p = cmd_list; p < cmd_list + nelem(cmd_list); p++)
1232 #ifdef SUPPORT_PROXY
1233 /* Only allow QUIT command if Proxy Protocol parsing failed */
1234 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1238 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1239 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1240 || smtp_cmd_buffer[p->len] == 0
1241 || smtp_cmd_buffer[p->len] == ' '
1244 if ( smtp_inptr < smtp_inend /* Outstanding input */
1245 && p->cmd < sync_cmd_limit /* Command should sync */
1246 && check_sync /* Local flag set */
1247 && smtp_enforce_sync /* Global flag set */
1248 && sender_host_address != NULL /* Not local input */
1249 && !f.sender_host_notsocket /* Really is a socket */
1253 /* The variables $smtp_command and $smtp_command_argument point into the
1254 unmodified input buffer. A copy of the latter is taken for actual
1255 processing, so that it can be chopped up into separate parts if necessary,
1256 for example, when processing a MAIL command options such as SIZE that can
1257 follow the sender address. */
1259 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1260 Uskip_whitespace(&smtp_cmd_argument);
1261 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1262 smtp_cmd_data = smtp_data_buffer;
1264 /* Count non-mail commands from those hosts that are controlled in this
1265 way. The default is all hosts. We don't waste effort checking the list
1266 until we get a non-mail command, but then cache the result to save checking
1267 again. If there's a DEFER while checking the host, assume it's in the list.
1269 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1270 start of each incoming message by fiddling with the value in the table. */
1272 if (!p->is_mail_cmd)
1274 if (count_nonmail == TRUE_UNSET) count_nonmail =
1275 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1276 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1277 return TOO_MANY_NONMAIL_CMD;
1280 /* If there is data for a command that does not expect it, generate the
1283 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1287 #ifdef SUPPORT_PROXY
1288 /* Only allow QUIT command if Proxy Protocol parsing failed */
1289 if (proxy_session && f.proxy_session_failed)
1290 return PROXY_FAIL_IGNORE_CMD;
1293 /* Enforce synchronization for unknown commands */
1295 if ( smtp_inptr < smtp_inend /* Outstanding input */
1296 && check_sync /* Local flag set */
1297 && smtp_enforce_sync /* Global flag set */
1298 && sender_host_address /* Not local input */
1299 && !f.sender_host_notsocket /* Really is a socket */
1309 /*************************************************
1310 * Forced closedown of call *
1311 *************************************************/
1313 /* This function is called from log.c when Exim is dying because of a serious
1314 disaster, and also from some other places. If an incoming non-batched SMTP
1315 channel is open, it swallows the rest of the incoming message if in the DATA
1316 phase, sends the reply string, and gives an error to all subsequent commands
1317 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1321 message SMTP reply string to send, excluding the code
1327 smtp_closedown(uschar * message)
1329 if (!smtp_in || smtp_batched_input) return;
1330 receive_swallow_smtp();
1331 smtp_printf("421 %s\r\n", SP_NO_MORE, message);
1333 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1339 f.smtp_in_quit = TRUE;
1340 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
1345 smtp_printf("250 Reset OK\r\n", SP_NO_MORE);
1349 smtp_printf("421 %s\r\n", SP_NO_MORE, message);
1357 /*************************************************
1358 * Set up connection info for logging *
1359 *************************************************/
1361 /* This function is called when logging information about an SMTP connection.
1362 It sets up appropriate source information, depending on the type of connection.
1363 If sender_fullhost is NULL, we are at a very early stage of the connection;
1364 just use the IP address.
1367 Returns: a string describing the connection
1371 smtp_get_connection_info(void)
1373 const uschar * hostname = sender_fullhost
1374 ? sender_fullhost : sender_host_address;
1375 gstring * g = string_catn(NULL, US"SMTP connection", 15);
1377 if (LOGGING(connection_id))
1378 g = string_fmt_append(g, " Ci=%s", connection_id);
1379 g = string_catn(g, US" from ", 6);
1382 g = string_cat(g, hostname);
1384 else if (f.sender_host_unknown || f.sender_host_notsocket)
1385 g = string_cat(g, sender_ident ? sender_ident : US"NULL");
1387 else if (f.is_inetd)
1388 g = string_append(g, 2, hostname, US" (via inetd)");
1390 else if (LOGGING(incoming_interface) && interface_address)
1391 g = string_fmt_append(g, "%s I=[%s]:%d", hostname, interface_address, interface_port);
1394 g = string_cat(g, hostname);
1396 gstring_release_unused(g);
1397 return string_from_gstring(g);
1403 /* Append TLS-related information to a log line
1406 g String under construction: allocated string to extend, or NULL
1408 Returns: Allocated string or NULL
1411 s_tlslog(gstring * g)
1413 if (LOGGING(tls_cipher) && tls_in.cipher)
1415 g = string_append(g, 2, US" X=", tls_in.cipher);
1416 #ifndef DISABLE_TLS_RESUME
1417 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1418 g = string_catn(g, US"*", 1);
1421 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1422 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1423 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1424 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1425 if (LOGGING(tls_sni) && tls_in.sni)
1426 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1434 s_connhad_log(gstring * g)
1436 const uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1437 ? US" C=..." : US" C=";
1439 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1440 if (smtp_connection_had[i] != SCH_NONE)
1442 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1445 for (int i = 0; i < smtp_ch_index; i++, sep = US",")
1446 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1451 /*************************************************
1452 * Log lack of MAIL if so configured *
1453 *************************************************/
1455 /* This function is called when an SMTP session ends. If the log selector
1456 smtp_no_mail is set, write a log line giving some details of what has happened
1457 in the SMTP session.
1464 smtp_log_no_mail(void)
1469 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1472 if (sender_host_authenticated)
1474 g = string_append(g, 2, US" A=", sender_host_authenticated);
1475 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1482 g = s_connhad_log(g);
1484 if (!(s = string_from_gstring(g))) s = US"";
1486 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1487 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1488 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1492 /* Return list of recent smtp commands */
1497 gstring * list = NULL;
1500 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1501 if (smtp_connection_had[i] != SCH_NONE)
1502 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1504 for (int i = 0; i < smtp_ch_index; i++)
1505 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1507 s = string_from_gstring(list);
1508 return s ? s : US"";
1514 /*************************************************
1515 * Check HELO line and set sender_helo_name *
1516 *************************************************/
1518 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1519 the domain name of the sending host, or an ip literal in square brackets. The
1520 argument is placed in sender_helo_name, which is in malloc store, because it
1521 must persist over multiple incoming messages. If helo_accept_junk is set, this
1522 host is permitted to send any old junk (needed for some broken hosts).
1523 Otherwise, helo_allow_chars can be used for rogue characters in general
1524 (typically people want to let in underscores).
1527 s the data portion of the line (already past any white space)
1529 Returns: TRUE or FALSE
1533 check_helo(uschar *s)
1536 uschar *end = s + Ustrlen(s);
1537 BOOL yield = fl.helo_accept_junk;
1539 /* Discard any previous helo name */
1541 sender_helo_name = NULL;
1543 /* Skip tests if junk is permitted. */
1547 /* Allow the new standard form for IPv6 address literals, namely,
1548 [IPv6:....], and because someone is bound to use it, allow an equivalent
1549 IPv4 form. Allow plain addresses as well. */
1556 if (strncmpic(s, US"[IPv6:", 6) == 0)
1557 yield = (string_is_ip_address(s+6, NULL) == 6);
1558 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1559 yield = (string_is_ip_address(s+6, NULL) == 4);
1561 yield = (string_is_ip_address(s+1, NULL) != 0);
1566 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1567 that have been configured (usually underscore - sigh). */
1570 for (yield = TRUE; *s; s++)
1571 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1572 Ustrchr(helo_allow_chars, *s) == NULL)
1578 /* Save argument if OK */
1580 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
1588 /*************************************************
1589 * Extract SMTP command option *
1590 *************************************************/
1592 /* This function picks the next option setting off the end of smtp_cmd_data. It
1593 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1594 things that can appear there.
1597 name point this at the name
1598 value point this at the data string
1600 Returns: TRUE if found an option
1604 extract_option(uschar **name, uschar **value)
1608 if (Ustrlen(smtp_cmd_data) <= 0) return FALSE;
1609 v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1610 while (v > smtp_cmd_data && isspace(*v)) v--;
1613 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1615 /* Take care to not stop at a space embedded in a quoted local-part */
1618 do v--; while (v > smtp_cmd_data && *v != '"');
1619 if (v <= smtp_cmd_data) return FALSE;
1623 if (v <= smtp_cmd_data) return FALSE;
1628 while (n > smtp_cmd_data && isalpha(n[-1])) n--;
1629 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1630 if (n <= smtp_cmd_data || !isspace(n[-1])) return FALSE;
1647 /*************************************************
1648 * Reset for new message *
1649 *************************************************/
1651 /* This function is called whenever the SMTP session is reset from
1652 within either of the setup functions; also from the daemon loop.
1654 Argument: the stacking pool storage reset point
1659 smtp_reset(void *reset_point)
1661 recipients_list = NULL;
1662 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1663 raw_recipients_count = recipients_count = recipients_list_max = 0;
1664 message_linecount = 0;
1666 message_body = message_body_end = NULL;
1667 acl_added_headers = NULL;
1668 acl_removed_headers = NULL;
1669 f.queue_only_policy = FALSE;
1670 rcpt_smtp_response = NULL;
1671 fl.rcpt_smtp_response_same = TRUE;
1672 fl.rcpt_in_progress = FALSE;
1673 f.deliver_freeze = FALSE; /* Can be set by ACL */
1674 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1675 fake_response = OK; /* Can be set by ACL */
1676 #ifdef WITH_CONTENT_SCAN
1677 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
1679 f.submission_mode = FALSE; /* Can be set by ACL */
1680 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
1681 f.active_local_from_check = local_from_check; /* Can be set by ACL */
1682 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1683 sending_ip_address = NULL;
1684 return_path = sender_address = NULL;
1685 deliver_localpart_data = deliver_domain_data =
1686 recipient_data = sender_data = NULL; /* Can be set by ACL */
1687 recipient_verify_failure = NULL;
1688 deliver_localpart_parent = deliver_localpart_orig = NULL;
1689 deliver_domain_parent = deliver_domain_orig = NULL;
1690 callout_address = NULL;
1691 submission_name = NULL; /* Can be set by ACL */
1692 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1693 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1694 sender_verified_list = NULL; /* No senders verified */
1695 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1696 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1698 authenticated_sender = NULL;
1699 #ifdef EXPERIMENTAL_BRIGHTMAIL
1701 bmi_verdicts = NULL;
1703 dnslist_domain = dnslist_matched = NULL;
1704 #ifdef EXPERIMENTAL_ARC
1705 arc_state = arc_state_reason = NULL;
1706 arc_received_instance = 0;
1710 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
1711 #ifndef DISABLE_PRDR
1712 prdr_requested = FALSE;
1715 message_smtputf8 = FALSE;
1717 #ifdef WITH_CONTENT_SCAN
1720 body_linecount = body_zerocount = 0;
1722 lookup_value = NULL; /* Can be set by ACL */
1723 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1724 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1725 /* Note that ratelimiters_conn persists across resets. */
1727 /* Reset message ACL variables */
1731 /* Warning log messages are saved in malloc store. They are saved to avoid
1732 repetition in the same message, but it seems right to repeat them for different
1735 while (acl_warn_logged)
1737 string_item *this = acl_warn_logged;
1738 acl_warn_logged = acl_warn_logged->next;
1742 misc_mod_smtp_reset();
1744 store_reset(reset_point);
1747 return store_mark();
1754 /*************************************************
1755 * Initialize for incoming batched SMTP message *
1756 *************************************************/
1758 /* This function is called from smtp_setup_msg() in the case when
1759 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1760 of messages in one file with SMTP commands between them. All errors must be
1761 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1762 relevant. After an error on a sender, or an invalid recipient, the remainder
1763 of the message is skipped. The value of received_protocol is already set.
1766 Returns: > 0 message successfully started (reached DATA)
1767 = 0 QUIT read or end of file reached
1768 < 0 should not occur
1772 smtp_setup_batch_msg(void)
1775 rmark reset_point = store_mark();
1777 /* Save the line count at the start of each transaction - single commands
1778 like HELO and RSET count as whole transactions. */
1780 bsmtp_transaction_linecount = receive_linecount;
1782 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1784 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
1785 reset_point = smtp_reset(reset_point); /* Reset for start of message */
1787 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1788 value. The values are 2 larger than the required yield of the function. */
1793 uschar *recipient = NULL;
1794 int start, end, sender_domain, recipient_domain;
1796 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1798 /* The HELO/EHLO commands set sender_address_helo if they have
1799 valid data; otherwise they are ignored, except that they do
1800 a reset of the state. */
1805 check_helo(smtp_cmd_data);
1809 cancel_cutthrough_connection(TRUE, US"RSET received");
1810 reset_point = smtp_reset(reset_point);
1811 bsmtp_transaction_linecount = receive_linecount;
1814 /* The MAIL FROM command requires an address as an operand. All we
1815 do here is to parse it for syntactic correctness. The form "<>" is
1816 a special case which converts into an empty string. The start/end
1817 pointers in the original are not used further for this address, as
1818 it is the canonical extracted address which is all that is kept. */
1821 smtp_mailcmd_count++; /* Count for no-mail log */
1823 /* The function moan_smtp_batch() does not return. */
1824 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1826 if (smtp_cmd_data[0] == 0)
1827 /* The function moan_smtp_batch() does not return. */
1828 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1830 /* Reset to start of message */
1832 cancel_cutthrough_connection(TRUE, US"MAIL received");
1833 reset_point = smtp_reset(reset_point);
1835 /* Apply SMTP rewrite */
1837 raw_sender = rewrite_existflags & rewrite_smtp
1838 /* deconst ok as smtp_cmd_data was not const */
1839 ? US rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL,
1840 FALSE, US"", global_rewrite_rules)
1843 /* Extract the address; the TRUE flag allows <> as valid */
1846 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1850 /* The function moan_smtp_batch() does not return. */
1851 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1853 sender_address = string_copy(raw_sender);
1855 /* Qualify unqualified sender addresses if permitted to do so. */
1858 && sender_address[0] != 0 && sender_address[0] != '@')
1859 if (f.allow_unqualified_sender)
1861 /* deconst ok as sender_address was not const */
1862 sender_address = US rewrite_address_qualify(sender_address, FALSE);
1863 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1864 "and rewritten\n", raw_sender);
1866 /* The function moan_smtp_batch() does not return. */
1868 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1873 /* The RCPT TO command requires an address as an operand. All we do
1874 here is to parse it for syntactic correctness. There may be any number
1875 of RCPT TO commands, specifying multiple senders. We build them all into
1876 a data structure that is in argc/argv format. The start/end values
1877 given by parse_extract_address are not used, as we keep only the
1878 extracted address. */
1881 if (!sender_address)
1882 /* The function moan_smtp_batch() does not return. */
1883 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1885 if (smtp_cmd_data[0] == 0)
1886 /* The function moan_smtp_batch() does not return. */
1887 moan_smtp_batch(smtp_cmd_buffer,
1888 "501 RCPT TO must have an address operand");
1890 /* Check maximum number allowed */
1892 if ( recipients_max_expanded > 0
1893 && recipients_count + 1 > recipients_max_expanded)
1894 /* The function moan_smtp_batch() does not return. */
1895 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1896 recipients_max_reject ? "552": "452");
1898 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1899 recipient address */
1901 recipient = rewrite_existflags & rewrite_smtp
1902 /* deconst ok as smtp_cmd_data was not const */
1903 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1904 global_rewrite_rules)
1907 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1908 &recipient_domain, FALSE);
1911 /* The function moan_smtp_batch() does not return. */
1912 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1914 /* If the recipient address is unqualified, qualify it if permitted. Then
1915 add it to the list of recipients. */
1917 if (!recipient_domain)
1918 if (f.allow_unqualified_recipient)
1920 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1922 /* deconst ok as recipient was not const */
1923 recipient = US rewrite_address_qualify(recipient, TRUE);
1925 /* The function moan_smtp_batch() does not return. */
1927 moan_smtp_batch(smtp_cmd_buffer,
1928 "501 recipient address must contain a domain");
1930 receive_add_recipient(recipient, -1);
1934 /* The DATA command is legal only if it follows successful MAIL FROM
1935 and RCPT TO commands. This function is complete when a valid DATA
1936 command is encountered. */
1939 if (!sender_address || recipients_count <= 0)
1940 /* The function moan_smtp_batch() does not return. */
1941 if (!sender_address)
1942 moan_smtp_batch(smtp_cmd_buffer,
1943 "503 MAIL FROM:<sender> command must precede DATA");
1945 moan_smtp_batch(smtp_cmd_buffer,
1946 "503 RCPT TO:<recipient> must precede DATA");
1949 done = 3; /* DATA successfully achieved */
1950 message_ended = END_NOTENDED; /* Indicate in middle of message */
1955 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1962 #ifndef DISABLE_WELLKNOWN
1965 bsmtp_transaction_linecount = receive_linecount;
1970 f.smtp_in_quit = TRUE;
1977 /* The function moan_smtp_batch() does not return. */
1978 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1983 /* The function moan_smtp_batch() does not return. */
1984 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1989 /* The function moan_smtp_batch() does not return. */
1990 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1995 return done - 2; /* Convert yield values */
2003 smtp_log_tls_fail(const uschar * errstr)
2005 const uschar * conn_info = smtp_get_connection_info();
2007 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2008 /* I'd like to get separated H= here, but too hard for now */
2010 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2024 socklen_t len = sizeof(is_fastopen);
2026 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2027 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2029 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2034 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2035 f.tcp_in_fastopen = TRUE;
2038 else DEBUG(D_receive)
2039 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2041 # elif defined(TCP_INFO)
2042 struct tcp_info tinfo;
2043 socklen_t len = sizeof(tinfo);
2045 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2046 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2047 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2050 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2051 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2055 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2058 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2059 f.tcp_in_fastopen = TRUE;
2061 else DEBUG(D_receive)
2062 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2069 log_connect_tls_drop(const uschar * what, const uschar * log_msg)
2071 if (log_reject_target)
2074 uschar * tls = NULL;
2076 gstring * g = s_tlslog(NULL);
2077 uschar * tls = string_from_gstring(g);
2079 log_write(L_connection_reject,
2080 log_reject_target, "%s%s%s dropped by %s%s%s",
2081 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
2082 host_and_ident(TRUE),
2085 log_msg ? US": " : US"", log_msg);
2090 /*************************************************
2091 * Start an SMTP session *
2092 *************************************************/
2094 /* This function is called at the start of an SMTP session. Thereafter,
2095 smtp_setup_msg() is called to initiate each separate message. This
2096 function does host-specific testing, and outputs the banner line.
2099 Returns: FALSE if the session can not continue; something has
2100 gone wrong, or the connection to the host is blocked
2104 smtp_start_session(void)
2107 uschar *user_msg, *log_msg;
2112 gettimeofday(&smtp_connection_start, NULL);
2113 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2114 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2117 /* Default values for certain variables */
2119 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2120 smtp_mailcmd_count = 0;
2121 count_nonmail = TRUE_UNSET;
2122 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2123 smtp_delay_mail = smtp_rlm_base;
2124 fl.auth_advertised = FALSE;
2125 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2126 f.pipelining_enable = TRUE;
2127 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2128 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2130 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2131 authentication settings from -oMaa to remain in force. */
2133 if (!host_checking && !f.sender_host_notsocket)
2134 sender_host_auth_pubname = sender_host_authenticated = NULL;
2135 authenticated_by = NULL;
2138 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2139 tls_in.ourcert = tls_in.peercert = NULL;
2141 tls_in.ocsp = OCSP_NOT_REQ;
2142 fl.tls_advertised = FALSE;
2144 fl.dsn_advertised = FALSE;
2146 fl.smtputf8_advertised = FALSE;
2149 /* Reset ACL connection variables */
2153 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2155 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, GET_TAINTED);
2157 smtp_cmd_buffer[0] = 0;
2158 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2160 /* For batched input, the protocol setting can be overridden from the
2161 command line by a trusted caller. */
2163 if (smtp_batched_input)
2165 if (!received_protocol) received_protocol = US"local-bsmtp";
2168 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2169 reset later if any of EHLO/AUTH/STARTTLS are received. */
2173 (sender_host_address ? protocols : protocols_local) [pnormal];
2175 /* Set up the buffer for inputting using direct read() calls, and arrange to
2176 call the local functions instead of the standard C ones. */
2180 receive_getc = smtp_getc;
2181 receive_getbuf = smtp_getbuf;
2182 receive_get_cache = smtp_get_cache;
2183 receive_hasc = smtp_hasc;
2184 receive_ungetc = smtp_ungetc;
2185 receive_feof = smtp_feof;
2186 receive_ferror = smtp_ferror;
2187 lwr_receive_getc = NULL;
2188 lwr_receive_getbuf = NULL;
2189 lwr_receive_hasc = NULL;
2190 lwr_receive_ungetc = NULL;
2192 /* Set up the message size limit; this may be host-specific */
2194 GET_OPTION("message_size_limit");
2195 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2196 if (expand_string_message)
2198 if (thismessage_size_limit == -1)
2199 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2200 "%s", expand_string_message);
2202 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2203 "%s", expand_string_message);
2204 smtp_closedown(US"Temporary local problem - please try later");
2208 /* When a message is input locally via the -bs or -bS options, sender_host_
2209 unknown is set unless -oMa was used to force an IP address, in which case it
2210 is checked like a real remote connection. When -bs is used from inetd, this
2211 flag is not set, causing the sending host to be checked. The code that deals
2212 with IP source routing (if configured) is never required for -bs or -bS and
2213 the flag sender_host_notsocket is used to suppress it.
2215 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2216 reserve for certain hosts and/or networks. */
2218 if (!f.sender_host_unknown)
2221 BOOL reserved_host = FALSE;
2223 /* Look up IP options (source routing info) on the socket if this is not an
2224 -oMa "host", and if any are found, log them and drop the connection.
2226 Linux (and others now, see below) is different to everyone else, so there
2227 has to be some conditional compilation here. Versions of Linux before 2.1.15
2228 used a structure whose name was "options". Somebody finally realized that
2229 this name was silly, and it got changed to "ip_options". I use the
2230 newer name here, but there is a fudge in the script that sets up os.h
2231 to define a macro in older Linux systems.
2233 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2234 glibc 2, which has chosen ip_opts for the structure name. This is now
2235 really a glibc thing rather than a Linux thing, so the condition name
2236 has been changed to reflect this. It is relevant also to GNU/Hurd.
2238 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2239 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2240 a special macro defined in the os.h file.
2242 Some DGUX versions on older hardware appear not to support IP options at
2243 all, so there is now a general macro which can be set to cut out this
2246 How to do this properly in IPv6 is not yet known. */
2248 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2250 # ifdef GLIBC_IP_OPTIONS
2251 # if (!defined __GLIBC__) || (__GLIBC__ < 2)
2256 # elif defined DARWIN_IP_OPTIONS
2262 if (!host_checking && !f.sender_host_notsocket)
2265 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2266 struct ip_options *ipopt = store_get(optlen, GET_UNTAINTED);
2267 # elif OPTSTYLE == 2
2268 struct ip_opts ipoptblock;
2269 struct ip_opts *ipopt = &ipoptblock;
2270 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2272 struct ipoption ipoptblock;
2273 struct ipoption *ipopt = &ipoptblock;
2274 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2277 /* Occasional genuine failures of getsockopt() have been seen - for
2278 example, "reset by peer". Therefore, just log and give up on this
2279 call, unless the error is ENOPROTOOPT. This error is given by systems
2280 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2281 of writing. So for that error, carry on - we just can't do an IP options
2284 DEBUG(D_receive) debug_printf("checking for IP options\n");
2286 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2289 if (errno != ENOPROTOOPT)
2291 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2292 host_and_ident(FALSE), strerror(errno));
2293 smtp_printf("451 SMTP service not available\r\n", SP_NO_MORE);
2298 /* Deal with any IP options that are set. On the systems I have looked at,
2299 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2300 more logging data than will fit in big_buffer. Nevertheless, after somebody
2301 questioned this code, I've added in some paranoid checking. */
2303 else if (optlen > 0)
2305 uschar * p = big_buffer;
2306 uschar * pend = big_buffer + big_buffer_size;
2309 struct in_addr addr;
2312 uschar * optstart = US (ipopt->__data);
2313 # elif OPTSTYLE == 2
2314 uschar * optstart = US (ipopt->ip_opts);
2316 uschar * optstart = US (ipopt->ipopt_list);
2319 DEBUG(D_receive) debug_printf("IP options exist\n");
2321 Ustrcpy(p, "IP options on incoming call:");
2324 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2339 string_format(p, pend-p, " %s [@%s",
2340 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2341 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr)))))
2342 # elif OPTSTYLE == 2
2343 string_format(p, pend-p, " %s [@%s",
2344 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2345 inet_ntoa(ipopt->ip_dst))
2347 string_format(p, pend-p, " %s [@%s",
2348 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2349 inet_ntoa(ipopt->ipopt_dst))
2358 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2360 while (optcount-- > 0)
2362 memcpy(&addr, adptr, sizeof(addr));
2363 if (!string_format(p, pend - p - 1, "%s%s",
2364 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2370 adptr += sizeof(struct in_addr);
2378 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2381 for (int i = 0; i < opt[1]; i++)
2382 p += sprintf(CS p, "%2.2x ", opt[i]);
2390 log_write(0, LOG_MAIN, "%s", big_buffer);
2392 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2394 log_write(0, LOG_MAIN|LOG_REJECT,
2395 "connection from %s refused (IP options)", host_and_ident(FALSE));
2397 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2401 /* Length of options = 0 => there are no options */
2403 else DEBUG(D_receive) debug_printf("no IP options found\n");
2405 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2407 /* Set keep-alive in socket options. The option is on by default. This
2408 setting is an attempt to get rid of some hanging connections that stick in
2409 read() when the remote end (usually a dialup) goes away. */
2411 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2412 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2414 /* If the current host matches host_lookup, set the name by doing a
2415 reverse lookup. On failure, sender_host_name will be NULL and
2416 host_lookup_failed will be TRUE. This may or may not be serious - optional
2419 if (verify_check_host(&host_lookup) == OK)
2421 (void)host_name_lookup();
2422 host_build_sender_fullhost();
2425 /* Delay this until we have the full name, if it is looked up. */
2427 set_process_info("handling incoming connection from %s",
2428 host_and_ident(FALSE));
2430 /* Expand smtp_receive_timeout, if needed */
2432 if (smtp_receive_timeout_s)
2435 if ( !(exp = expand_string(smtp_receive_timeout_s))
2437 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2439 log_write(0, LOG_MAIN|LOG_PANIC,
2440 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2443 /* Test for explicit connection rejection */
2445 if (verify_check_host(&host_reject_connection) == OK)
2447 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2448 "from %s (host_reject_connection)", host_and_ident(FALSE));
2450 if (!tls_in.on_connect)
2452 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2456 /* Test with TCP Wrappers if so configured. There is a problem in that
2457 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2458 such as disks dying. In these cases, it is desirable to reject with a 4xx
2459 error instead of a 5xx error. There isn't a "right" way to detect such
2460 problems. The following kludge is used: errno is zeroed before calling
2461 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2462 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2465 #ifdef USE_TCP_WRAPPERS
2467 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2468 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2469 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2470 expand_string_message);
2472 if (!hosts_ctl(tcp_wrappers_name,
2473 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2474 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2475 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2477 if (errno == 0 || errno == ENOENT)
2479 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2480 log_write(L_connection_reject,
2481 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2482 "(tcp wrappers)", host_and_ident(FALSE));
2483 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2487 int save_errno = errno;
2488 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2489 "errno value %d\n", save_errno);
2490 log_write(L_connection_reject,
2491 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2492 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2493 smtp_printf("451 Temporary local problem - please try later\r\n", SP_NO_MORE);
2499 /* Check for reserved slots. The value of smtp_accept_count has already been
2500 incremented to include this process. */
2502 if (smtp_accept_max > 0 &&
2503 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2505 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2507 log_write(L_connection_reject,
2508 LOG_MAIN, "temporarily refused connection from %s: not in "
2509 "reserve list: connected=%d max=%d reserve=%d%s",
2510 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2511 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2512 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2513 "please try again later\r\n", SP_NO_MORE, smtp_active_hostname);
2516 reserved_host = TRUE;
2519 /* If a load level above which only messages from reserved hosts are
2520 accepted is set, check the load. For incoming calls via the daemon, the
2521 check is done in the superior process if there are no reserved hosts, to
2522 save a fork. In all cases, the load average will already be available
2523 in a global variable at this point. */
2525 if (smtp_load_reserve >= 0 &&
2526 load_average > smtp_load_reserve &&
2528 verify_check_host(&smtp_reserve_hosts) != OK)
2530 log_write(L_connection_reject,
2531 LOG_MAIN, "temporarily refused connection from %s: not in "
2532 "reserve list and load average = %.2f", host_and_ident(FALSE),
2533 (double)load_average/1000.0);
2534 smtp_printf("421 %s: Too much load; please try again later\r\n", SP_NO_MORE,
2535 smtp_active_hostname);
2539 /* Determine whether unqualified senders or recipients are permitted
2540 for this host. Unfortunately, we have to do this every time, in order to
2541 set the flags so that they can be inspected when considering qualifying
2542 addresses in the headers. For a site that permits no qualification, this
2543 won't take long, however. */
2545 f.allow_unqualified_sender =
2546 verify_check_host(&sender_unqualified_hosts) == OK;
2548 f.allow_unqualified_recipient =
2549 verify_check_host(&recipient_unqualified_hosts) == OK;
2551 /* Determine whether HELO/EHLO is required for this host. The requirement
2552 can be hard or soft. */
2554 fl.helo_verify_required = verify_check_host(&helo_verify_hosts) == OK;
2555 if (!fl.helo_verify_required)
2556 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2558 /* Determine whether this hosts is permitted to send syntactic junk
2559 after a HELO or EHLO command. */
2561 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2564 /* Expand recipients_max, if needed */
2566 uschar * rme = expand_string(recipients_max);
2567 recipients_max_expanded = atoi(CCS rme);
2569 /* For batch SMTP input we are now done. */
2571 if (smtp_batched_input) return TRUE;
2573 #if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS) || defined(EXPERIMENTAL_XCLIENT)
2574 proxy_session = FALSE;
2577 #ifdef SUPPORT_PROXY
2578 /* If valid Proxy Protocol source is connecting, set up session.
2579 Failure will not allow any SMTP function other than QUIT. */
2581 f.proxy_session_failed = FALSE;
2582 if (proxy_protocol_host())
2584 os_non_restarting_signal(SIGALRM, command_timeout_handler);
2585 proxy_protocol_setup();
2589 /* Run the connect ACL if it exists */
2592 GET_OPTION("acl_smtp_connect");
2593 if (acl_smtp_connect)
2596 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2600 if (tls_in.on_connect)
2601 log_connect_tls_drop(US"'connect' ACL", log_msg);
2604 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2609 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2610 smtps port for use with older style SSL MTAs. */
2613 if (tls_in.on_connect)
2615 if (tls_server_start(&user_msg) != OK)
2616 return smtp_log_tls_fail(user_msg);
2617 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
2621 /* Output the initial message for a two-way SMTP connection. It may contain
2622 newlines, which then cause a multi-line response to be given. */
2624 code = US"220"; /* Default status code */
2625 esc = US""; /* Default extended status code */
2626 esclen = 0; /* Length of esc */
2632 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2636 esclen = codelen - 4;
2641 GET_OPTION("smtp_banner");
2642 if (!(s = expand_string(smtp_banner)))
2644 log_write(0, f.expand_string_forcedfail ? LOG_MAIN : LOG_MAIN|LOG_PANIC_DIE,
2645 "Expansion of \"%s\" (smtp_banner) failed: %s",
2646 smtp_banner, expand_string_message);
2647 /* for force-fail */
2649 if (tls_in.on_connect) tls_close(NULL, TLS_SHUTDOWN_WAIT);
2655 /* Remove any terminating newlines; might as well remove trailing space too */
2658 while (p > s && isspace(p[-1])) p--;
2659 s = string_copyn(s, p-s);
2661 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2662 is all contained in a single IP packet. The original code wrote out the
2663 greeting using several calls to fprint/fputc, and on busy servers this could
2664 cause it to be split over more than one packet - which caused CC:Mail to fall
2665 over when it got the second part of the greeting after sending its first
2666 command. Sigh. To try to avoid this, build the complete greeting message
2667 first, and output it in one fell swoop. This gives a better chance of it
2668 ending up as a single packet. */
2670 ss = string_get(256);
2673 do /* At least once, in case we have an empty string */
2676 uschar *linebreak = Ustrchr(p, '\n');
2677 ss = string_catn(ss, code, 3);
2681 ss = string_catn(ss, US" ", 1);
2685 len = linebreak - p;
2686 ss = string_catn(ss, US"-", 1);
2688 ss = string_catn(ss, esc, esclen);
2689 ss = string_catn(ss, p, len);
2690 ss = string_catn(ss, US"\r\n", 2);
2696 /* Before we write the banner, check that there is no input pending, unless
2697 this synchronisation check is disabled. */
2699 #ifndef DISABLE_PIPE_CONNECT
2700 fl.pipe_connect_acceptable =
2701 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
2704 if (fl.pipe_connect_acceptable)
2705 f.smtp_in_early_pipe_used = TRUE;
2711 unsigned n = smtp_inend - smtp_inptr;
2712 if (n > 128) n = 128;
2714 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2715 "synchronization error (input sent without waiting for greeting): "
2716 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2717 string_printing(string_copyn(smtp_inptr, n)));
2718 smtp_printf("554 SMTP synchronization error\r\n", SP_NO_MORE);
2722 /* Now output the banner */
2723 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
2726 #ifndef DISABLE_PIPE_CONNECT
2727 fl.pipe_connect_acceptable && pipeline_connect_sends(),
2733 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2734 handshake arrived. If so we must have managed a TFO. */
2737 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
2747 /*************************************************
2748 * Handle SMTP syntax and protocol errors *
2749 *************************************************/
2751 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2752 to do so. Then transmit the error response. The return value depends on the
2753 number of syntax and protocol errors in this SMTP session.
2756 type error type, given as a log flag bit
2757 code response code; <= 0 means don't send a response
2758 data data to reflect in the response (can be NULL)
2759 errmess the error message
2761 Returns: -1 limit of syntax/protocol errors NOT exceeded
2762 +1 limit of syntax/protocol errors IS exceeded
2764 These values fit in with the values of the "done" variable in the main
2765 processing loop in smtp_setup_msg(). */
2768 synprot_error(int type, int code, uschar *data, uschar *errmess)
2772 #ifndef DISABLE_EVENT
2773 event_raise(event_action,
2774 L_smtp_syntax_error ? US"smtp:fail:syntax" : US"smtp:fail:protocol",
2778 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2779 type == L_smtp_syntax_error ? "syntax" : "protocol",
2780 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2782 if (++synprot_error_count > smtp_max_synprot_errors)
2785 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2786 "syntax or protocol errors (last command was \"%s\", %Y)",
2787 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
2794 smtp_printf("%d%c%s%s%s\r\n", SP_NO_MORE, code, yield == 1 ? '-' : ' ',
2795 data ? data : US"", data ? US": " : US"", errmess);
2797 smtp_printf("%d Too many syntax or protocol errors\r\n", SP_NO_MORE, code);
2806 /*************************************************
2807 * Send SMTP response, possibly multiline *
2808 *************************************************/
2810 /* There are, it seems, broken clients out there that cannot handle multiline
2811 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2812 output nothing for non-final calls, and only the first line for anything else.
2815 code SMTP code, may involve extended status codes
2816 codelen length of smtp code; if > 4 there's an ESC
2817 final FALSE if the last line isn't the final line
2818 msg message text, possibly containing newlines
2824 smtp_respond(uschar * code, int codelen, BOOL final, uschar * msg)
2829 if (!final && f.no_multiline_responses) return;
2834 esclen = codelen - 4;
2837 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2838 have had the same. Note: this code is also present in smtp_printf(). It would
2839 be tidier to have it only in one place, but when it was added, it was easier to
2840 do it that way, so as not to have to mess with the code for the RCPT command,
2841 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2843 if (fl.rcpt_in_progress)
2845 if (!rcpt_smtp_response)
2846 rcpt_smtp_response = string_copy(msg);
2847 else if (fl.rcpt_smtp_response_same &&
2848 Ustrcmp(rcpt_smtp_response, msg) != 0)
2849 fl.rcpt_smtp_response_same = FALSE;
2850 fl.rcpt_in_progress = FALSE;
2853 /* Now output the message, splitting it up into multiple lines if necessary.
2854 We only handle pipelining these responses as far as nonfinal/final groups,
2855 not the whole MAIL/RCPT/DATA response set. */
2858 if (!(nl = Ustrchr(msg, '\n')))
2860 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
2863 else if (nl[1] == 0 || f.no_multiline_responses)
2865 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
2866 (int)(nl - msg), msg);
2871 smtp_printf("%.3s-%.*s%.*s\r\n", SP_MORE, code, esclen, esc, (int)(nl - msg), msg);
2873 Uskip_whitespace(&msg);
2880 /*************************************************
2881 * Parse user SMTP message *
2882 *************************************************/
2884 /* This function allows for user messages overriding the response code details
2885 by providing a suitable response code string at the start of the message
2886 user_msg. Check the message for starting with a response code and optionally an
2887 extended status code. If found, check that the first digit is valid, and if so,
2888 change the code pointer and length to use the replacement. An invalid code
2889 causes a panic log; in this case, if the log messages is the same as the user
2890 message, we must also adjust the value of the log message to show the code that
2891 is actually going to be used (the original one).
2893 This function is global because it is called from receive.c as well as within
2896 Note that the code length returned includes the terminating whitespace
2897 character, which is always included in the regex match.
2900 code SMTP code, may involve extended status codes
2901 codelen length of smtp code; if > 4 there's an ESC
2903 log_msg optional log message, to be adjusted with the new SMTP code
2904 check_valid if true, verify the response code
2910 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2916 if (!msg || !*msg || !regex_match(regex_smtp_code, *msg, -1, &match))
2919 len = Ustrlen(match);
2920 if (check_valid && (*msg)[0] != (*code)[0])
2922 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2923 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2924 if (log_msg && *log_msg == *msg)
2925 *log_msg = string_sprintf("%s %s", *code, *log_msg + len);
2930 *codelen = len; /* Includes final space */
2932 *msg += len; /* Chop the code off the message */
2939 /*************************************************
2940 * Handle an ACL failure *
2941 *************************************************/
2943 /* This function is called when acl_check() fails. As well as calls from within
2944 this module, it is called from receive.c for an ACL after DATA. It sorts out
2945 logging the incident, and sends the error response. A message containing
2946 newlines is turned into a multiline SMTP response, but for logging, only the
2949 There's a table of default permanent failure response codes to use in
2950 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2951 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2952 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2953 state, because there are broken clients that try VRFY before RCPT. A 5xx
2954 response should be given only when the address is positively known to be
2955 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2956 no explicit code, but if there is one we let it know best.
2957 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2959 From Exim 4.63, it is possible to override the response code details by
2960 providing a suitable response code string at the start of the message provided
2961 in user_msg. The code's first digit is checked for validity.
2964 where where the ACL was called from
2966 user_msg a message that can be included in an SMTP response
2967 log_msg a message for logging
2969 Returns: 0 in most cases
2970 2 if the failure code was FAIL_DROP, in which case the
2971 SMTP connection should be dropped (this value fits with the
2972 "done" variable in smtp_setup_msg() below)
2976 smtp_handle_acl_fail(int where, int rc, uschar * user_msg, uschar * log_msg)
2978 BOOL drop = rc == FAIL_DROP;
2982 uschar *sender_info = US"";
2985 if (drop) rc = FAIL;
2987 /* Set the default SMTP code, and allow a user message to change it. */
2989 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2990 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2991 where != ACL_WHERE_VRFY);
2993 /* Get info for logging.
2994 We used to have sender_address here; however, there was a bug that was not
2995 updating sender_address after a rewrite during a verify. When this bug was
2996 fixed, sender_address at this point became the rewritten address. I'm not sure
2997 this is what should be logged, so I've changed to logging the unrewritten
2998 address to retain backward compatibility. */
3002 #ifdef WITH_CONTENT_SCAN
3003 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
3005 case ACL_WHERE_PREDATA: what = US"DATA"; break;
3006 case ACL_WHERE_DATA: what = US"after DATA"; break;
3007 #ifndef DISABLE_PRDR
3008 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
3012 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
3015 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
3017 uschar * s = smtp_cmd_data;
3019 lim = s - smtp_cmd_data; /* stop after method */
3021 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
3026 case ACL_WHERE_RCPT:
3027 case ACL_WHERE_DATA:
3028 #ifdef WITH_CONTENT_SCAN
3029 case ACL_WHERE_MIME:
3031 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3032 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3033 sender_host_authenticated ? US" A=" : US"",
3034 sender_host_authenticated ? sender_host_authenticated : US"",
3035 sender_host_authenticated && authenticated_id ? US":" : US"",
3036 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3041 /* If there's been a sender verification failure with a specific message, and
3042 we have not sent a response about it yet, do so now, as a preliminary line for
3043 failures, but not defers. However, always log it for defer, and log it for fail
3044 unless the sender_verify_fail log selector has been turned off. */
3046 if (sender_verified_failed &&
3047 !testflag(sender_verified_failed, af_sverify_told))
3049 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3050 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3052 setflag(sender_verified_failed, af_sverify_told);
3054 if (rc != FAIL || LOGGING(sender_verify_fail))
3055 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3056 host_and_ident(TRUE),
3057 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3058 sender_verified_failed->address,
3059 (sender_verified_failed->message == NULL)? US"" :
3060 string_sprintf(": %s", sender_verified_failed->message));
3062 if (rc == FAIL && sender_verified_failed->user_message)
3063 smtp_respond(smtp_code, codelen, SR_NOT_FINAL, string_sprintf(
3064 testflag(sender_verified_failed, af_verify_pmfail)?
3065 "Postmaster verification failed while checking <%s>\n%s\n"
3066 "Several RFCs state that you are required to have a postmaster\n"
3067 "mailbox for each mail domain. This host does not accept mail\n"
3068 "from domains whose servers reject the postmaster address."
3070 testflag(sender_verified_failed, af_verify_nsfail)?
3071 "Callback setup failed while verifying <%s>\n%s\n"
3072 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3073 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3074 "RFC requirements, and stops you from receiving standard bounce\n"
3075 "messages. This host does not accept mail from domains whose servers\n"
3078 "Verification failed for <%s>\n%s",
3079 sender_verified_failed->address,
3080 sender_verified_failed->user_message));
3082 fl.rcpt_in_progress = save_rcpt_in_progress;
3085 /* Sort out text for logging */
3087 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3088 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3090 /* Send permanent failure response to the command, but the code used isn't
3091 always a 5xx one - see comments at the start of this function. If the original
3092 rc was FAIL_DROP we drop the connection and yield 2. */
3095 smtp_respond(smtp_code, codelen, SR_FINAL,
3096 user_msg ? user_msg : US"Administrative prohibition");
3098 /* Send temporary failure response to the command. Don't give any details,
3099 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3100 verb, and for a header verify when smtp_return_error_details is set.
3102 This conditional logic is all somewhat of a mess because of the odd
3103 interactions between temp_details and return_error_details. One day it should
3104 be re-implemented in a tidier fashion. */
3107 if (f.acl_temp_details && user_msg)
3109 if ( smtp_return_error_details
3110 && sender_verified_failed
3111 && sender_verified_failed->message
3113 smtp_respond(smtp_code, codelen, SR_NOT_FINAL, sender_verified_failed->message);
3115 smtp_respond(smtp_code, codelen, SR_FINAL, user_msg);
3118 smtp_respond(smtp_code, codelen, SR_FINAL,
3119 US"Temporary local problem - please try later");
3121 /* Log the incident to the logs that are specified by log_reject_target
3122 (default main, reject). This can be empty to suppress logging of rejections. If
3123 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3124 is closing if required and return 2. */
3126 if (log_reject_target)
3129 gstring * g = s_tlslog(NULL);
3130 uschar * tls = string_from_gstring(g);
3131 if (!tls) tls = US"";
3133 uschar * tls = US"";
3135 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3136 log_reject_target, "%s%s%s %s%srejected %s%s",
3137 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3138 host_and_ident(TRUE),
3141 rc == FAIL ? US"" : US"temporarily ",
3145 if (!drop) return 0;
3147 log_close_event(US"by DROP in ACL");
3149 /* Run the not-quit ACL, but without any custom messages. This should not be a
3150 problem, because we get here only if some other ACL has issued "drop", and
3151 in that case, *its* custom messages will have been used above. */
3153 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3155 /* An overenthusiastic fail2ban/iptables implimentation has been seen to result
3156 in the TCP conn staying open, and retrying, despite this process exiting. A
3157 malicious client could possibly do the same, tying up server netowrking
3158 resources. Close the socket explicitly to try to avoid that (there's a note in
3159 the Linux socket(7) manpage, SO_LINGER para, to the effect that exim() without
3160 close() results in the socket always lingering). */
3162 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3163 DEBUG(D_any) debug_printf_indent("SMTP(close)>>\n");
3164 (void) fclose(smtp_in);
3165 (void) fclose(smtp_out);
3173 /*************************************************
3174 * Handle SMTP exit when QUIT is not given *
3175 *************************************************/
3177 /* This function provides a logging/statistics hook for when an SMTP connection
3178 is dropped on the floor or the other end goes away. It's a global function
3179 because it's called from receive.c as well as this module. As well as running
3180 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3181 response, either with a custom message from the ACL, or using a default. There
3182 is one case, however, when no message is output - after "drop". In that case,
3183 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3184 passed to this function.
3186 In case things go wrong while processing this function, causing an error that
3187 may re-enter this function, there is a recursion check.
3190 reason What $smtp_notquit_reason will be set to in the ACL;
3191 if NULL, the ACL is not run
3192 code The error code to return as part of the response
3193 defaultrespond The default message if there's no user_msg
3199 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3202 uschar *user_msg = NULL;
3203 uschar *log_msg = NULL;
3205 /* Check for recursive call */
3207 if (fl.smtp_exit_function_called)
3209 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3213 fl.smtp_exit_function_called = TRUE;
3215 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3217 GET_OPTION("acl_smtp_notquit");
3218 if (acl_smtp_notquit && reason)
3220 smtp_notquit_reason = reason;
3221 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3222 &log_msg)) == ERROR)
3223 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3227 /* If the connection was dropped, we certainly are no longer talking TLS */
3228 tls_in.active.sock = -1;
3230 /* Write an SMTP response if we are expected to give one. As the default
3231 responses are all internal, they should be reasonable size. */
3233 if (code && defaultrespond)
3236 smtp_respond(code, 3, SR_FINAL, user_msg);
3242 va_start(ap, defaultrespond);
3243 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3245 smtp_printf("%s %Y\r\n", SP_NO_MORE, code, g);
3254 /*************************************************
3255 * Verify HELO argument *
3256 *************************************************/
3258 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3259 matched. It is also called from ACL processing if verify = helo is used and
3260 verification was not previously tried (i.e. helo_try_verify_hosts was not
3261 matched). The result of its processing is to set helo_verified and
3262 helo_verify_failed. These variables should both be FALSE for this function to
3265 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3266 for IPv6 ::ffff: literals.
3269 Returns: TRUE if testing was completed;
3270 FALSE on a temporary failure
3274 smtp_verify_helo(void)
3278 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3281 if (sender_helo_name == NULL)
3283 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3286 /* Deal with the case of -bs without an IP address */
3288 else if (sender_host_address == NULL)
3290 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3291 f.helo_verified = TRUE;
3294 /* Deal with the more common case when there is a sending IP address */
3296 else if (sender_helo_name[0] == '[')
3298 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3299 Ustrlen(sender_host_address)) == 0;
3302 if (!f.helo_verified)
3304 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3305 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3306 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3311 { if (f.helo_verified) debug_printf("matched host address\n"); }
3314 /* Do a reverse lookup if one hasn't already given a positive or negative
3315 response. If that fails, or the name doesn't match, try checking with a forward
3320 if (sender_host_name == NULL && !host_lookup_failed)
3321 yield = host_name_lookup() != DEFER;
3323 /* If a host name is known, check it and all its aliases. */
3325 if (sender_host_name)
3326 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3328 sender_helo_dnssec = sender_host_dnssec;
3329 HDEBUG(D_receive) debug_printf("matched host name\n");
3333 uschar **aliases = sender_host_aliases;
3335 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3337 sender_helo_dnssec = sender_host_dnssec;
3341 HDEBUG(D_receive) if (f.helo_verified)
3342 debug_printf("matched alias %s\n", *(--aliases));
3345 /* Final attempt: try a forward lookup of the helo name */
3347 if (!f.helo_verified)
3351 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3353 {.request = US"*", .require = US""};
3355 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3357 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3358 NULL, NULL, NULL, &d, NULL, NULL);
3359 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3360 for (host_item * hh = &h; hh; hh = hh->next)
3361 if (Ustrcmp(hh->address, sender_host_address) == 0)
3363 f.helo_verified = TRUE;
3364 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3366 debug_printf("IP address for %s matches calling address\n"
3367 "Forward DNS security status: %sverified\n",
3368 sender_helo_name, sender_helo_dnssec ? "" : "un");
3374 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3381 /*************************************************
3382 * Send user response message *
3383 *************************************************/
3385 /* This function is passed a default response code and a user message. It calls
3386 smtp_message_code() to check and possibly modify the response code, and then
3387 calls smtp_respond() to transmit the response. I put this into a function
3388 just to avoid a lot of repetition.
3391 code the response code
3392 user_msg the user message
3398 smtp_user_msg(uschar * code, uschar * user_msg)
3401 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3402 smtp_respond(code, len, SR_FINAL, user_msg);
3408 smtp_in_auth(auth_instance *au, uschar ** smtp_resp, uschar ** errmsg)
3410 const uschar *set_id = NULL;
3413 /* Set up globals for error messages */
3415 authenticator_name = au->drinst.name;
3416 driver_srcfile = au->drinst.srcfile;
3417 driver_srcline = au->drinst.srcline;
3419 /* Run the checking code, passing the remainder of the command line as
3420 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3421 it as the only set numerical variable. The authenticator may set $auth<n>
3422 and also set other numeric variables. The $auth<n> variables are preferred
3423 nowadays; the numerical variables remain for backwards compatibility.
3425 Afterwards, have a go at expanding the set_id string, even if
3426 authentication failed - for bad passwords it can be useful to log the
3427 userid. On success, require set_id to expand and exist, and put it in
3428 authenticated_id. Save this in permanent store, as the working store gets
3429 reset at HELO, RSET, etc. */
3431 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3433 expand_nlength[0] = 0; /* $0 contains nothing */
3436 auth_info * ai = au->drinst.info;
3437 rc = (ai->servercode)(au, smtp_cmd_data);
3439 if (au->set_id) set_id = expand_string(au->set_id);
3440 expand_nmax = -1; /* Reset numeric variables */
3441 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3442 driver_srcfile = authenticator_name = NULL; driver_srcline = 0;
3444 /* The value of authenticated_id is stored in the spool file and printed in
3445 log lines. It must not contain binary zeros or newline characters. In
3446 normal use, it never will, but when playing around or testing, this error
3447 can (did) happen. To guard against this, ensure that the id contains only
3448 printing characters. */
3450 if (set_id) set_id = string_printing(set_id);
3452 /* For the non-OK cases, set up additional logging data if set_id
3456 set_id = set_id && *set_id
3457 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3459 /* Switch on the result */
3464 if (!au->set_id || set_id) /* Complete success */
3466 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3467 sender_host_authenticated = au->drinst.name;
3468 sender_host_auth_pubname = au->public_name;
3469 authentication_failed = FALSE;
3470 authenticated_fail_id = NULL; /* Impossible to already be set? */
3473 (sender_host_address ? protocols : protocols_local)
3474 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3475 *smtp_resp = *errmsg = US"235 Authentication succeeded";
3476 authenticated_by = au;
3480 /* Authentication succeeded, but we failed to expand the set_id string.
3481 Treat this as a temporary error. */
3483 auth_defer_msg = expand_string_message;
3487 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3488 *smtp_resp = string_sprintf("435 Unable to authenticate at present%s",
3489 auth_defer_user_msg);
3490 *errmsg = string_sprintf("435 Unable to authenticate at present%s: %s",
3491 set_id, auth_defer_msg);
3495 *smtp_resp = *errmsg = US"501 Invalid base64 data";
3499 *smtp_resp = *errmsg = US"501 Authentication cancelled";
3503 *smtp_resp = *errmsg = US"553 Initial data not expected";
3507 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3508 *smtp_resp = US"535 Incorrect authentication data";
3509 *errmsg = string_sprintf("535 Incorrect authentication data%s", set_id);
3513 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3514 *smtp_resp = US"435 Internal error";
3515 *errmsg = string_sprintf("435 Internal error%s: return %d from authentication "
3516 "check", set_id, rc);
3528 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3531 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3533 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3535 rd = Ustrlen(recipient) + 1;
3536 /* deconst ok as *recipient was not const */
3537 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3540 smtp_printf("501 %s: recipient address must contain a domain\r\n", SP_NO_MORE,
3542 log_write(L_smtp_syntax_error,
3543 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3544 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3552 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3555 f.smtp_in_quit = TRUE;
3556 incomplete_transaction_log(US"QUIT");
3557 GET_OPTION("acl_smtp_quit");
3559 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3561 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3564 #ifdef EXIM_TCP_CORK
3565 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
3569 smtp_respond(US"221", 3, SR_FINAL, *user_msgp);
3571 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
3573 #ifdef SERVERSIDE_CLOSE_NOWAIT
3574 # ifndef DISABLE_TLS
3575 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3578 log_close_event(US"by QUIT");
3581 # ifndef DISABLE_TLS
3582 tls_close(NULL, TLS_SHUTDOWN_WAIT);
3585 log_close_event(US"by QUIT");
3587 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
3588 The socket should become readble (though with no data) */
3590 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3591 #endif /*!SERVERSIDE_CLOSE_NOWAIT*/
3596 smtp_rset_handler(void)
3599 incomplete_transaction_log(US"RSET");
3600 smtp_printf("250 Reset OK\r\n", SP_NO_MORE);
3601 cmd_list[CL_RSET].is_mail_cmd = FALSE;
3602 if (chunking_state > CHUNKING_OFFERED)
3603 chunking_state = CHUNKING_OFFERED;
3607 #ifndef DISABLE_WELLKNOWN
3609 smtp_wellknown_handler(void)
3611 if (verify_check_host(&wellknown_advertise_hosts) != FAIL)
3613 GET_OPTION("acl_smtp_wellknown");
3614 if (acl_smtp_wellknown)
3616 uschar * user_msg = NULL, * log_msg;
3619 if ((rc = acl_check(ACL_WHERE_WELLKNOWN, NULL, acl_smtp_wellknown,
3620 &user_msg, &log_msg)) != OK)
3621 return smtp_handle_acl_fail(ACL_WHERE_WELLKNOWN, rc, user_msg, log_msg);
3622 else if (!wellknown_response)
3623 return smtp_handle_acl_fail(ACL_WHERE_WELLKNOWN, ERROR, user_msg, log_msg);
3624 smtp_user_msg(US"250", wellknown_response);
3629 smtp_printf("554 not permitted\r\n", SP_NO_MORE);
3630 log_write(0, LOG_MAIN|LOG_REJECT, "rejected \"%s\" from %s",
3631 smtp_cmd_buffer, sender_helo_name, host_and_ident(FALSE));
3638 expand_mailmax(const uschar * s)
3640 if (!(s = expand_cstring(s)))
3641 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
3642 return *s ? Uatoi(s) : 0;
3645 /*************************************************
3646 * Initialize for SMTP incoming message *
3647 *************************************************/
3649 /* This function conducts the initial dialogue at the start of an incoming SMTP
3650 message, and builds a list of recipients. However, if the incoming message
3651 is part of a batch (-bS option) a separate function is called since it would
3652 be messy having tests splattered about all over this function. This function
3653 therefore handles the case where interaction is occurring. The input and output
3654 files are set up in smtp_in and smtp_out.
3656 The global recipients_list is set to point to a vector of recipient_item
3657 blocks, whose number is given by recipients_count. This is extended by the
3658 receive_add_recipient() function. The global variable sender_address is set to
3659 the sender's address. The yield is +1 if a message has been successfully
3660 started, 0 if a QUIT command was encountered or the connection was refused from
3661 the particular host, or -1 if the connection was lost.
3665 Returns: > 0 message successfully started (reached DATA)
3666 = 0 QUIT read or end of file reached or call refused
3671 smtp_setup_msg(void)
3674 BOOL toomany = FALSE;
3675 BOOL discarded = FALSE;
3676 BOOL last_was_rej_mail = FALSE;
3677 BOOL last_was_rcpt = FALSE;
3678 rmark reset_point = store_mark();
3680 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3682 /* Reset for start of new message. We allow one RSET not to be counted as a
3683 nonmail command, for those MTAs that insist on sending it between every
3684 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3685 TLS between messages (an Exim client may do this if it has messages queued up
3686 for the host). Note: we do NOT reset AUTH at this point. */
3688 reset_point = smtp_reset(reset_point);
3689 message_ended = END_NOTSTARTED;
3691 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3693 cmd_list[CL_RSET].is_mail_cmd = TRUE;
3694 cmd_list[CL_HELO].is_mail_cmd = TRUE;
3695 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
3697 cmd_list[CL_STLS].is_mail_cmd = TRUE;
3700 if (lwr_receive_getc != NULL)
3702 /* This should have already happened, but if we've gotten confused,
3703 force a reset here. */
3704 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
3705 bdat_pop_receive_functions();
3708 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3710 had_command_sigterm = 0;
3711 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3713 /* Batched SMTP is handled in a different function. */
3715 if (smtp_batched_input) return smtp_setup_batch_msg();
3718 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3719 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3720 US &off, sizeof(off));
3723 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3724 value. The values are 2 larger than the required yield of the function. */
3728 const uschar **argv;
3729 uschar *etrn_command;
3730 uschar *etrn_serialize_key;
3732 uschar *log_msg, *smtp_code;
3733 uschar *user_msg = NULL;
3734 uschar *recipient = NULL;
3735 uschar *hello = NULL;
3737 BOOL was_rej_mail = FALSE;
3738 BOOL was_rcpt = FALSE;
3739 void (*oldsignal)(int);
3741 int start, end, sender_domain, recipient_domain;
3743 uschar * orcpt = NULL;
3748 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3749 if ( tls_in.active.sock >= 0
3751 && tls_in.certificate_verified
3752 && cmd_list[CL_TLAU].is_mail_cmd
3755 cmd_list[CL_TLAU].is_mail_cmd = FALSE;
3757 for (auth_instance * au = auths; au; au = au->drinst.next)
3758 if (strcmpic(US"tls", au->drinst.driver_name) == 0)
3760 GET_OPTION("acl_smtp_auth");
3762 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3763 &user_msg, &log_msg)) != OK
3765 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3768 smtp_cmd_data = NULL;
3770 if (smtp_in_auth(au, &s, &ss) == OK)
3771 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3774 DEBUG(D_auth) debug_printf("tls auth not succeeded\n");
3775 #ifndef DISABLE_EVENT
3777 uschar * save_name = sender_host_authenticated, * logmsg;
3778 sender_host_authenticated = au->drinst.name;
3779 if ((logmsg = event_raise(event_action, US"auth:fail", s, NULL)))
3780 log_write(0, LOG_MAIN, "%s", logmsg);
3781 sender_host_authenticated = save_name;
3791 switch(smtp_read_command(
3792 #ifndef DISABLE_PIPE_CONNECT
3793 !fl.pipe_connect_acceptable,
3797 GETC_BUFFER_UNLIMITED))
3799 /* The AUTH command is not permitted to occur inside a transaction, and may
3800 occur successfully only once per connection. Actually, that isn't quite
3801 true. When TLS is started, all previous information about a connection must
3802 be discarded, so a new AUTH is permitted at that time.
3804 AUTH may only be used when it has been advertised. However, it seems that
3805 there are clients that send AUTH when it hasn't been advertised, some of
3806 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3807 So there's a get-out that allows this to happen.
3809 AUTH is initially labelled as a "nonmail command" so that one occurrence
3810 doesn't get counted. We change the label here so that multiple failing
3811 AUTHS will eventually hit the nonmail threshold. */
3815 authentication_failed = TRUE;
3816 cmd_list[CL_AUTH].is_mail_cmd = FALSE;
3818 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
3820 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3821 US"AUTH command used when not advertised");
3824 if (sender_host_authenticated)
3826 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3827 US"already authenticated");
3832 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3833 US"not permitted in mail transaction");
3839 GET_OPTION("acl_smtp_auth");
3841 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3842 &user_msg, &log_msg)) != OK
3845 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3849 /* Find the name of the requested authentication mechanism. */
3852 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
3853 if (!isalnum(c) && c != '-' && c != '_')
3855 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3856 US"invalid character in authentication mechanism name");
3860 /* If not at the end of the line, we must be at white space. Terminate the
3861 name and move the pointer on to any data that may be present. */
3865 *smtp_cmd_data++ = '\0';
3866 Uskip_whitespace(&smtp_cmd_data);
3869 /* Search for an authentication mechanism which is configured for use
3870 as a server and which has been advertised (unless, sigh, allow_auth_
3871 unadvertised is set). */
3875 uschar * smtp_resp, * errmsg;
3877 for (au = auths; au; au = au->drinst.next)
3878 if (strcmpic(s, au->public_name) == 0 && au->server &&
3879 (au->advertised || f.allow_auth_unadvertised))
3884 int rc = smtp_in_auth(au, &smtp_resp, &errmsg);
3886 smtp_printf("%s\r\n", SP_NO_MORE, smtp_resp);
3889 uschar * logmsg = NULL;
3890 #ifndef DISABLE_EVENT
3891 {uschar * save_name = sender_host_authenticated;
3892 sender_host_authenticated = au->drinst.name;
3893 logmsg = event_raise(event_action, US"auth:fail", smtp_resp, NULL);
3894 sender_host_authenticated = save_name;
3898 log_write(0, LOG_MAIN|LOG_REJECT, "%s", logmsg);
3900 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3901 au->drinst.name, host_and_ident(FALSE), errmsg);
3905 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3906 string_sprintf("%s authentication mechanism not supported", s));
3909 break; /* AUTH_CMD */
3911 /* The HELO/EHLO commands are permitted to appear in the middle of a
3912 session as well as at the beginning. They have the effect of a reset in
3913 addition to their other functions. Their absence at the start cannot be
3914 taken to be an error.
3918 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3919 or 502 failure replies MUST be returned as appropriate. The SMTP
3920 server MUST stay in the same state after transmitting these replies
3921 that it was in before the EHLO was received.
3923 Therefore, we do not do the reset until after checking the command for
3924 acceptability. This change was made for Exim release 4.11. Previously
3925 it did the reset first. */
3938 HELO_EHLO: /* Common code for HELO and EHLO */
3939 cmd_list[CL_HELO].is_mail_cmd = FALSE;
3940 cmd_list[CL_EHLO].is_mail_cmd = FALSE;
3942 /* Reject the HELO if its argument was invalid or non-existent. A
3943 successful check causes the argument to be saved in malloc store. */
3945 if (!check_helo(smtp_cmd_data))
3947 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", SP_NO_MORE, hello);
3949 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3950 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3951 *smtp_cmd_argument == 0 ? US"(no argument given)" :
3952 string_printing(smtp_cmd_argument));
3954 if (++synprot_error_count > smtp_max_synprot_errors)
3956 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3957 "syntax or protocol errors (last command was \"%s\", %Y)",
3958 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3967 /* If sender_host_unknown is true, we have got here via the -bs interface,
3968 not called from inetd. Otherwise, we are running an IP connection and the
3969 host address will be set. If the helo name is the primary name of this
3970 host and we haven't done a reverse lookup, force one now. If helo_verify_required
3971 is set, ensure that the HELO name matches the actual host. If helo_verify
3972 is set, do the same check, but softly. */
3974 if (!f.sender_host_unknown)
3976 BOOL old_helo_verified = f.helo_verified;
3977 uschar * p = smtp_cmd_data;
3979 while (*p && !isspace(*p)) { *p = tolower(*p); p++; }
3982 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3983 because otherwise the log can be confusing. */
3985 if ( !sender_host_name
3986 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3987 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
3988 (void)host_name_lookup();
3990 /* Rebuild the fullhost info to include the HELO name (and the real name
3991 if it was looked up.) */
3993 host_build_sender_fullhost(); /* Rebuild */
3994 set_process_info("handling%s incoming connection from %s",
3995 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
3997 /* Verify if configured. This doesn't give much security, but it does
3998 make some people happy to be able to do it. If helo_verify_required is set,
3999 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4000 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4001 now obsolescent, since the verification can now be requested selectively
4004 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4005 if (fl.helo_verify_required || fl.helo_verify)
4007 BOOL tempfail = !smtp_verify_helo();
4008 if (!f.helo_verified)
4010 if (fl.helo_verify_required)
4012 smtp_printf("%d %s argument does not match calling host\r\n", SP_NO_MORE,
4013 tempfail? 451 : 550, hello);
4014 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4015 tempfail? "temporarily " : "",
4016 hello, sender_helo_name, host_and_ident(FALSE));
4017 f.helo_verified = old_helo_verified;
4018 break; /* End of HELO/EHLO processing */
4020 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4021 "helo_try_verify_hosts\n", hello);
4026 /* For any misc-module having a connection-init routine, call it. */
4028 if (misc_mod_conn_init(sender_helo_name, sender_host_address) != OK)
4030 DEBUG(D_receive) debug_printf("A module conn-init routine failed\n");
4035 /* Apply an ACL check if one is defined; afterwards, recheck
4036 synchronization in case the client started sending in a delay. */
4038 GET_OPTION("acl_smtp_helo");
4040 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4041 &user_msg, &log_msg)) != OK)
4043 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4044 sender_helo_name = NULL;
4045 host_build_sender_fullhost(); /* Rebuild */
4048 #ifndef DISABLE_PIPE_CONNECT
4049 else if (!fl.pipe_connect_acceptable && !check_sync())
4051 else if (!check_sync())
4055 /* Generate an OK reply. The default string includes the ident if present,
4056 and also the IP address if present. Reflecting back the ident is intended
4057 as a deterrent to mail forgers. For maximum efficiency, and also because
4058 some broken systems expect each response to be in a single packet, arrange
4059 that the entire reply is sent in one write(). */
4061 fl.auth_advertised = FALSE;
4062 f.smtp_in_pipelining_advertised = FALSE;
4064 fl.tls_advertised = FALSE;
4066 fl.dsn_advertised = FALSE;
4068 fl.smtputf8_advertised = FALSE;
4071 /* Expand the per-connection message count limit option */
4072 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4074 smtp_code = US"250 "; /* Default response code plus space*/
4077 /* sender_host_name below will be tainted, so save on copy when we hit it */
4078 g = string_get_tainted(24, GET_TAINTED);
4079 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4081 smtp_active_hostname,
4082 sender_ident ? sender_ident : US"",
4083 sender_ident ? US" at " : US"",
4084 sender_host_name ? sender_host_name : sender_helo_name);
4086 if (sender_host_address)
4087 g = string_fmt_append(g, " [%s]", sender_host_address);
4090 /* A user-supplied EHLO greeting may not contain more than one line. Note
4091 that the code returned by smtp_message_code() includes the terminating
4092 whitespace character. */
4098 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4099 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4100 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4102 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4103 "newlines: message truncated: %s", string_printing(s));
4106 g = string_cat(NULL, s);
4109 g = string_catn(g, US"\r\n", 2);
4111 /* If we received EHLO, we must create a multiline response which includes
4112 the functions supported. */
4116 g->s[3] = '-'; /* overwrite the space after the SMTP response code */
4118 /* I'm not entirely happy with this, as an MTA is supposed to check
4119 that it has enough room to accept a message of maximum size before
4120 it sends this. However, there seems little point in not sending it.
4121 The actual size check happens later at MAIL FROM time. By postponing it
4122 till then, VRFY and EXPN can be used after EHLO when space is short. */
4124 if (thismessage_size_limit > 0)
4125 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4126 thismessage_size_limit);
4129 g = string_catn(g, smtp_code, 3);
4130 g = string_catn(g, US"-SIZE\r\n", 7);
4133 #ifndef DISABLE_ESMTP_LIMITS
4134 if ( (smtp_mailcmd_max > 0 || recipients_max_expanded > 0)
4135 && verify_check_host(&limits_advertise_hosts) == OK)
4137 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4138 if (smtp_mailcmd_max > 0)
4139 g = string_fmt_append(g, " MAILMAX=%d", smtp_mailcmd_max);
4140 if (recipients_max_expanded > 0)
4141 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max_expanded);
4142 g = string_catn(g, US"\r\n", 2);
4146 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4147 clean; if it has an 8-bit character in its hand, it just sends it. It
4148 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4149 However, some users want this option simply in order to stop MUAs
4150 mangling messages that contain top-bit-set characters. It is therefore
4151 provided as an option. */
4153 if (accept_8bitmime)
4155 g = string_catn(g, smtp_code, 3);
4156 g = string_catn(g, US"-8BITMIME\r\n", 11);
4159 /* Advertise DSN support if configured to do so. */
4160 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4162 g = string_catn(g, smtp_code, 3);
4163 g = string_catn(g, US"-DSN\r\n", 6);
4164 fl.dsn_advertised = TRUE;
4167 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4168 permitted to issue them; a check is made when any host actually tries. */
4170 GET_OPTION("acl_smtp_etrn");
4173 g = string_catn(g, smtp_code, 3);
4174 g = string_catn(g, US"-ETRN\r\n", 7);
4176 GET_OPTION("acl_smtp_vrfy");
4179 g = string_catn(g, smtp_code, 3);
4180 g = string_catn(g, US"-VRFY\r\n", 7);
4182 GET_OPTION("acl_smtp_expn");
4185 g = string_catn(g, smtp_code, 3);
4186 g = string_catn(g, US"-EXPN\r\n", 7);
4189 /* Exim is quite happy with pipelining, so let the other end know that
4190 it is safe to use it, unless advertising is disabled. */
4192 if ( f.pipelining_enable
4193 && verify_check_host(&pipelining_advertise_hosts) == OK)
4195 g = string_catn(g, smtp_code, 3);
4196 g = string_catn(g, US"-PIPELINING\r\n", 13);
4197 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4198 f.smtp_in_pipelining_advertised = TRUE;
4200 #ifndef DISABLE_PIPE_CONNECT
4201 if (fl.pipe_connect_acceptable)
4203 f.smtp_in_early_pipe_advertised = TRUE;
4204 g = string_catn(g, smtp_code, 3);
4205 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4211 /* If any server authentication mechanisms are configured, advertise
4212 them if the current host is in auth_advertise_hosts. The problem with
4213 advertising always is that some clients then require users to
4214 authenticate (and aren't configurable otherwise) even though it may not
4215 be necessary (e.g. if the host is in host_accept_relay).
4217 RFC 2222 states that SASL mechanism names contain only upper case
4218 letters, so output the names in upper case, though we actually recognize
4219 them in either case in the AUTH command. */
4223 && !sender_host_authenticated
4225 && verify_check_host(&auth_advertise_hosts) == OK
4229 for (auth_instance * au = auths; au; au = au->drinst.next)
4231 au->advertised = FALSE;
4234 DEBUG(D_auth+D_expand) debug_printf_indent(
4235 "Evaluating advertise_condition for %s %s athenticator\n",
4236 au->drinst.name, au->public_name);
4237 if ( !au->advertise_condition
4238 || expand_check_condition(au->advertise_condition,
4239 au->drinst.name, US"authenticator")
4245 g = string_catn(g, smtp_code, 3);
4246 g = string_catn(g, US"-AUTH", 5);
4248 fl.auth_advertised = TRUE;
4250 saveptr = gstring_length(g);
4251 g = string_catn(g, US" ", 1);
4252 g = string_cat(g, au->public_name);
4253 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4254 au->advertised = TRUE;
4259 if (!first) g = string_catn(g, US"\r\n", 2);
4262 /* RFC 3030 CHUNKING */
4264 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4266 g = string_catn(g, smtp_code, 3);
4267 g = string_catn(g, US"-CHUNKING\r\n", 11);
4268 f.chunking_offered = TRUE;
4269 chunking_state = CHUNKING_OFFERED;
4273 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4274 if it has been included in the binary, and the host matches
4275 tls_advertise_hosts. We must *not* advertise if we are already in a
4276 secure connection. */
4278 if (tls_in.active.sock < 0 &&
4279 verify_check_host(&tls_advertise_hosts) != FAIL)
4281 g = string_catn(g, smtp_code, 3);
4282 g = string_catn(g, US"-STARTTLS\r\n", 11);
4283 fl.tls_advertised = TRUE;
4286 #ifdef EXPERIMENTAL_XCLIENT
4287 if (proxy_session || verify_check_host(&hosts_xclient) != FAIL)
4289 g = string_catn(g, smtp_code, 3);
4290 g = xclient_smtp_advertise_str(g);
4293 #ifndef DISABLE_PRDR
4294 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4297 g = string_catn(g, smtp_code, 3);
4298 g = string_catn(g, US"-PRDR\r\n", 7);
4303 if ( accept_8bitmime
4304 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4306 g = string_catn(g, smtp_code, 3);
4307 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4308 fl.smtputf8_advertised = TRUE;
4311 #ifndef DISABLE_WELLKNOWN
4312 if (verify_check_host(&wellknown_advertise_hosts) != FAIL)
4314 g = string_catn(g, smtp_code, 3);
4315 g = string_catn(g, US"-WELLKNOWN\r\n", 12);
4319 /* Finish off the multiline reply with one that is always available. */
4321 g = string_catn(g, smtp_code, 3);
4322 g = string_catn(g, US" HELP\r\n", 7);
4325 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4330 int len = len_string_from_gstring(g, &ehlo_resp);
4332 if (tls_in.active.sock >= 0)
4333 (void) tls_write(NULL, ehlo_resp, len,
4334 # ifndef DISABLE_PIPE_CONNECT
4335 fl.pipe_connect_acceptable && pipeline_connect_sends());
4341 (void) fwrite(ehlo_resp, 1, len, smtp_out);
4343 DEBUG(D_receive) for (const uschar * t, * s = ehlo_resp;
4344 s && (t = Ustrchr(s, '\r'));
4345 s = t + 2) /* \r\n */
4346 debug_printf("%s %.*s\n",
4347 s == g->s ? "SMTP>>" : " ",
4349 fl.helo_seen = TRUE;
4352 /* Reset the protocol and the state, abandoning any previous message. */
4354 (sender_host_address ? protocols : protocols_local)
4356 ? pextend + (sender_host_authenticated ? pauthed : 0)
4358 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4360 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4361 reset_point = smtp_reset(reset_point);
4363 break; /* HELO/EHLO */
4365 #ifndef DISABLE_WELLKNOWN
4368 smtp_mailcmd_count++;
4369 smtp_wellknown_handler();
4373 #ifdef EXPERIMENTAL_XCLIENT
4376 BOOL fatal = fl.helo_seen;
4381 smtp_mailcmd_count++;
4383 if ((errmsg = xclient_smtp_command(smtp_cmd_data, &resp, &fatal)))
4385 done = synprot_error(L_smtp_syntax_error, resp, NULL, errmsg);
4388 smtp_printf("%d %s\r\n", SP_NO_MORE, resp, errmsg);
4389 log_write(0, LOG_MAIN|LOG_REJECT, "rejected XCLIENT from %s: %s",
4390 host_and_ident(FALSE), errmsg);
4394 fl.helo_seen = FALSE; /* Require another EHLO */
4395 smtp_code = string_sprintf("%d", resp);
4397 /*XXX unclear in spec. if this needs to be an ESMTP banner,
4398 nor whether we get the original client's HELO after (or a proxy fake).
4399 We require that we do; the following HELO/EHLO handling will set
4400 sender_helo_name as normal. */
4402 smtp_printf("%s XCLIENT success\r\n", SP_NO_MORE, smtp_code);
4404 break; /* XCLIENT */
4409 /* The MAIL command requires an address as an operand. All we do
4410 here is to parse it for syntactic correctness. The form "<>" is
4411 a special case which converts into an empty string. The start/end
4412 pointers in the original are not used further for this address, as
4413 it is the canonical extracted address which is all that is kept. */
4417 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4419 was_rej_mail = TRUE; /* Reset if accepted */
4420 env_mail_type_t * mail_args; /* Sanity check & validate args */
4423 if ( fl.helo_verify_required
4424 || verify_check_host(&hosts_require_helo) == OK)
4426 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4427 "HELO/EHLO given", host_and_ident(FALSE));
4428 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4429 US"HELO or EHLO required");
4432 else if (smtp_mailcmd_max < 0)
4433 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4437 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4438 US"sender already given");
4442 if (!*smtp_cmd_data)
4444 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4445 US"MAIL must have an address operand");
4449 /* Check to see if the limit for messages per connection would be
4450 exceeded by accepting further messages. */
4452 if (smtp_mailcmd_max > 0 && smtp_mailcmd_count > smtp_mailcmd_max)
4454 smtp_printf("421 too many messages in this connection\r\n", SP_NO_MORE);
4455 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4456 "messages in one connection", host_and_ident(TRUE));
4460 /* Reset for start of message - even if this is going to fail, we
4461 obviously need to throw away any previous data. */
4463 cancel_cutthrough_connection(TRUE, US"MAIL received");
4464 reset_point = smtp_reset(reset_point);
4466 sender_data = recipient_data = NULL;
4468 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4470 if (fl.esmtp) for(;;)
4472 uschar *name, *value, *end;
4473 unsigned long int size;
4474 BOOL arg_error = FALSE;
4476 if (!extract_option(&name, &value)) break;
4478 for (mail_args = env_mail_type_list;
4479 mail_args->value != ENV_MAIL_OPT_NULL;
4482 if (strcmpic(name, mail_args->name) == 0)
4484 if (mail_args->need_value && strcmpic(value, US"") == 0)
4487 switch(mail_args->value)
4489 /* Handle SIZE= by reading the value. We don't do the check till later,
4490 in order to be able to log the sender address on failure. */
4491 case ENV_MAIL_OPT_SIZE:
4492 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4494 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4496 message_size = (int)size;
4502 /* If this session was initiated with EHLO and accept_8bitmime is set,
4503 Exim will have indicated that it supports the BODY=8BITMIME option. In
4504 fact, it does not support this according to the RFCs, in that it does not
4505 take any special action for forwarding messages containing 8-bit
4506 characters. That is why accept_8bitmime is not the default setting, but
4507 some sites want the action that is provided. We recognize both "8BITMIME"
4508 and "7BIT" as body types, but take no action. */
4509 case ENV_MAIL_OPT_BODY:
4510 if (accept_8bitmime) {
4511 if (strcmpic(value, US"8BITMIME") == 0)
4513 else if (strcmpic(value, US"7BIT") == 0)
4518 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4519 US"invalid data for BODY");
4522 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4528 /* Handle the two DSN options, but only if configured to do so (which
4529 will have caused "DSN" to be given in the EHLO response). The code itself
4530 is included only if configured in at build time. */
4532 case ENV_MAIL_OPT_RET:
4533 if (fl.dsn_advertised)
4535 /* Check if RET has already been set */
4538 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4539 US"RET can be specified once only");
4542 dsn_ret = strcmpic(value, US"HDRS") == 0
4544 : strcmpic(value, US"FULL") == 0
4547 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4548 /* Check for invalid invalid value, and exit with error */
4551 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4552 US"Value for RET is invalid");
4557 case ENV_MAIL_OPT_ENVID:
4558 if (fl.dsn_advertised)
4560 /* Check if the dsn envid has been already set */
4563 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4564 US"ENVID can be specified once only");
4567 dsn_envid = string_copy(value);
4568 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4572 /* Handle the AUTH extension. If the value given is not "<>" and either
4573 the ACL says "yes" or there is no ACL but the sending host is
4574 authenticated, we set it up as the authenticated sender. However, if the
4575 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4576 the condition is met. The value of AUTH is an xtext, which means that +,
4577 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4579 case ENV_MAIL_OPT_AUTH:
4580 if (Ustrcmp(value, "<>") != 0)
4585 if (xtextdecode(value, &authenticated_sender) < 0)
4587 /* Put back terminator overrides for error message */
4590 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4591 US"invalid data for AUTH");
4594 GET_OPTION("acl_smtp_mailauth");
4595 if (!acl_smtp_mailauth)
4597 ignore_msg = US"client not authenticated";
4598 rc = sender_host_authenticated ? OK : FAIL;
4602 ignore_msg = US"rejected by ACL";
4603 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4604 &user_msg, &log_msg);
4610 if (authenticated_by == NULL ||
4611 authenticated_by->mail_auth_condition == NULL ||
4612 expand_check_condition(authenticated_by->mail_auth_condition,
4613 authenticated_by->drinst.name, US"authenticator"))
4614 break; /* Accept the AUTH */
4616 ignore_msg = US"server_mail_auth_condition failed";
4617 if (authenticated_id != NULL)
4618 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4619 ignore_msg, authenticated_id);
4624 authenticated_sender = NULL;
4625 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4626 value, host_and_ident(TRUE), ignore_msg);
4629 /* Should only get DEFER or ERROR here. Put back terminator
4630 overrides for error message */
4635 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4642 #ifndef DISABLE_PRDR
4643 case ENV_MAIL_OPT_PRDR:
4645 prdr_requested = TRUE;
4650 case ENV_MAIL_OPT_UTF8:
4651 if (!fl.smtputf8_advertised)
4653 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4654 US"SMTPUTF8 used when not advertised");
4658 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4659 message_smtputf8 = allow_utf8_domains = TRUE;
4660 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4662 int old_pool = store_pool;
4663 store_pool = POOL_PERM;
4664 received_protocol = string_sprintf("utf8%s", received_protocol);
4665 store_pool = old_pool;
4670 /* No valid option. Stick back the terminator characters and break
4671 the loop. Do the name-terminator second as extract_option sets
4672 value==name when it found no equal-sign.
4673 An error for a malformed address will occur. */
4674 case ENV_MAIL_OPT_NULL:
4682 /* Break out of for loop if switch() had bad argument or
4683 when start of the email address is reached */
4684 if (arg_error) break;
4687 /* If we have passed the threshold for rate limiting, apply the current
4688 delay, and update it for next time, provided this is a limited host. */
4690 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4691 verify_check_host(&smtp_ratelimit_hosts) == OK)
4693 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4694 smtp_delay_mail/1000.0);
4695 millisleep((int)smtp_delay_mail);
4696 smtp_delay_mail *= smtp_rlm_factor;
4697 if (smtp_delay_mail > (double)smtp_rlm_limit)
4698 smtp_delay_mail = (double)smtp_rlm_limit;
4701 /* Now extract the address, first applying any SMTP-time rewriting. The
4702 TRUE flag allows "<>" as a sender address. */
4704 raw_sender = rewrite_existflags & rewrite_smtp
4705 /* deconst ok as smtp_cmd_data was not const */
4706 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4707 global_rewrite_rules)
4711 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4716 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4720 sender_address = raw_sender;
4722 /* If there is a configured size limit for mail, check that this message
4723 doesn't exceed it. The check is postponed to this point so that the sender
4726 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4728 smtp_printf("552 Message size exceeds maximum permitted\r\n", SP_NO_MORE);
4729 log_write(L_size_reject,
4730 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4731 "message too big: size%s=%d max=%d",
4733 host_and_ident(TRUE),
4734 (message_size == INT_MAX)? ">" : "",
4736 thismessage_size_limit);
4737 sender_address = NULL;
4741 /* Check there is enough space on the disk unless configured not to.
4742 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4743 plus the current message - i.e. we accept the message only if it won't
4744 reduce the space below the threshold. Add 5000 to the size to allow for
4745 overheads such as the Received: line and storing of recipients, etc.
4746 By putting the check here, even when SIZE is not given, it allow VRFY
4747 and EXPN etc. to be used when space is short. */
4749 if (!receive_check_fs(
4750 smtp_check_spool_space && message_size >= 0
4751 ? message_size + 5000 : 0))
4753 smtp_printf("452 Space shortage, please try later\r\n", SP_NO_MORE);
4754 sender_address = NULL;
4758 /* If sender_address is unqualified, reject it, unless this is a locally
4759 generated message, or the sending host or net is permitted to send
4760 unqualified addresses - typically local machines behaving as MUAs -
4761 in which case just qualify the address. The flag is set above at the start
4762 of the SMTP connection. */
4764 if (!sender_domain && *sender_address)
4765 if (f.allow_unqualified_sender)
4767 sender_domain = Ustrlen(sender_address) + 1;
4768 /* deconst ok as sender_address was not const */
4769 sender_address = US rewrite_address_qualify(sender_address, FALSE);
4770 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4775 smtp_printf("501 %s: sender address must contain a domain\r\n", SP_NO_MORE,
4777 log_write(L_smtp_syntax_error,
4778 LOG_MAIN|LOG_REJECT,
4779 "unqualified sender rejected: <%s> %s%s",
4781 host_and_ident(TRUE),
4783 sender_address = NULL;
4787 /* Apply an ACL check if one is defined, before responding. Afterwards,
4788 when pipelining is not advertised, do another sync check in case the ACL
4789 delayed and the client started sending in the meantime. */
4791 GET_OPTION("acl_smtp_mail");
4794 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4795 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4801 if (rc == OK || rc == DISCARD)
4803 BOOL more = pipeline_response();
4806 smtp_printf("%s%s%s", more, US"250 OK",
4807 #ifndef DISABLE_PRDR
4808 prdr_requested ? US", PRDR Requested" : US"",
4815 #ifndef DISABLE_PRDR
4817 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4819 smtp_user_msg(US"250", user_msg);
4821 smtp_delay_rcpt = smtp_rlr_base;
4822 f.recipients_discarded = (rc == DISCARD);
4823 was_rej_mail = FALSE;
4827 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4828 sender_address = NULL;
4833 /* The RCPT command requires an address as an operand. There may be any
4834 number of RCPT commands, specifying multiple recipients. We build them all
4835 into a data structure. The start/end values given by parse_extract_address
4836 are not used, as we keep only the extracted address. */
4840 /* We got really to many recipients. A check against configured
4841 limits is done later */
4842 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
4843 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
4845 was_rcpt = fl.rcpt_in_progress = TRUE;
4847 /* There must be a sender address; if the sender was rejected and
4848 pipelining was advertised, we assume the client was pipelining, and do not
4849 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4850 get the same treatment. */
4852 if (!sender_address)
4854 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4856 smtp_printf("503 sender not yet given\r\n", SP_NO_MORE);
4857 was_rej_mail = TRUE;
4861 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4862 US"sender not yet given");
4863 was_rcpt = FALSE; /* Not a valid RCPT */
4869 /* Check for an operand */
4871 if (!smtp_cmd_data[0])
4873 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4874 US"RCPT must have an address operand");
4879 /* Set the DSN flags orcpt and dsn_flags from the session*/
4883 if (fl.esmtp) for(;;)
4885 uschar *name, *value;
4887 if (!extract_option(&name, &value))
4890 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4892 /* Check whether orcpt has been already set */
4895 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4896 US"ORCPT can be specified once only");
4899 orcpt = string_copy(value);
4900 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4903 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4905 /* Check if the notify flags have been already set */
4908 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4909 US"NOTIFY can be specified once only");
4912 if (strcmpic(value, US"NEVER") == 0)
4913 dsn_flags |= rf_notify_never;
4920 while (*pp != 0 && *pp != ',') pp++;
4921 if (*pp == ',') *pp++ = 0;
4922 if (strcmpic(p, US"SUCCESS") == 0)
4924 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4925 dsn_flags |= rf_notify_success;
4927 else if (strcmpic(p, US"FAILURE") == 0)
4929 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4930 dsn_flags |= rf_notify_failure;
4932 else if (strcmpic(p, US"DELAY") == 0)
4934 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4935 dsn_flags |= rf_notify_delay;
4939 /* Catch any strange values */
4940 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4941 US"Invalid value for NOTIFY parameter");
4946 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
4950 /* Unknown option. Stick back the terminator characters and break
4951 the loop. An error for a malformed address will occur. */
4955 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4962 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4963 as a recipient address */
4965 recipient = rewrite_existflags & rewrite_smtp
4966 /* deconst ok as smtp_cmd_data was not const */
4967 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4968 global_rewrite_rules)
4971 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4972 &recipient_domain, FALSE)))
4974 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4979 /* If the recipient address is unqualified, reject it, unless this is a
4980 locally generated message. However, unqualified addresses are permitted
4981 from a configured list of hosts and nets - typically when behaving as
4982 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4983 really. The flag is set at the start of the SMTP connection.
4985 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4986 assumed this meant "reserved local part", but the revision of RFC 821 and
4987 friends now makes it absolutely clear that it means *mailbox*. Consequently
4988 we must always qualify this address, regardless. */
4990 if (!recipient_domain)
4991 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4998 /* Check maximum allowed */
5000 if ( rcpt_count+1 < 0
5001 || rcpt_count > recipients_max_expanded && recipients_max_expanded > 0)
5003 if (recipients_max_reject)
5006 smtp_printf("552 too many recipients\r\n", SP_NO_MORE);
5008 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5009 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5014 smtp_printf("452 too many recipients\r\n", SP_NO_MORE);
5016 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5017 "temporarily rejected: sender=<%s> %s", sender_address,
5018 host_and_ident(TRUE));
5025 /* If we have passed the threshold for rate limiting, apply the current
5026 delay, and update it for next time, provided this is a limited host. */
5028 if (rcpt_count > smtp_rlr_threshold &&
5029 verify_check_host(&smtp_ratelimit_hosts) == OK)
5031 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5032 smtp_delay_rcpt/1000.0);
5033 millisleep((int)smtp_delay_rcpt);
5034 smtp_delay_rcpt *= smtp_rlr_factor;
5035 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5036 smtp_delay_rcpt = (double)smtp_rlr_limit;
5039 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5040 for them. Otherwise, check the access control list for this recipient. As
5041 there may be a delay in this, re-check for a synchronization error
5042 afterwards, unless pipelining was advertised. */
5044 if (f.recipients_discarded)
5048 GET_OPTION("acl_smtp_rcpt");
5049 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5051 && !f.smtp_in_pipelining_advertised && !check_sync())
5055 /* The ACL was happy */
5059 BOOL more = pipeline_response();
5062 smtp_user_msg(US"250", user_msg);
5064 smtp_printf("250 Accepted\r\n", more);
5065 receive_add_recipient(recipient, -1);
5067 /* Set the dsn flags in the recipients_list */
5068 recipients_list[recipients_count-1].orcpt = orcpt;
5069 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5071 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5072 recipients_list[recipients_count-1].orcpt,
5073 recipients_list[recipients_count-1].dsn_flags); */
5076 /* The recipient was discarded */
5078 else if (rc == DISCARD)
5081 smtp_user_msg(US"250", user_msg);
5083 smtp_printf("250 Accepted\r\n", SP_NO_MORE);
5086 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5087 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5088 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5089 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5090 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5093 /* Either the ACL failed the address, or it was deferred. */
5097 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5098 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5103 /* The DATA command is legal only if it follows successful MAIL FROM
5104 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5105 not counted as a protocol error if it follows RCPT (which must have been
5106 rejected if there are no recipients.) This function is complete when a
5107 valid DATA command is encountered.
5109 Note concerning the code used: RFC 2821 says this:
5111 - If there was no MAIL, or no RCPT, command, or all such commands
5112 were rejected, the server MAY return a "command out of sequence"
5113 (503) or "no valid recipients" (554) reply in response to the
5116 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5117 because it is the same whether pipelining is in use or not.
5119 If all the RCPT commands that precede DATA provoked the same error message
5120 (often indicating some kind of system error), it is helpful to include it
5121 with the DATA rejection (an idea suggested by Tony Finch). */
5128 if (chunking_state != CHUNKING_OFFERED)
5130 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5131 US"BDAT command used when CHUNKING not advertised");
5135 /* grab size, endmarker */
5137 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5139 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5140 US"missing size for BDAT command");
5143 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5144 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5145 chunking_data_left = chunking_datasize;
5146 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5147 (int)chunking_state, chunking_data_left);
5149 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
5158 f.bdat_readers_wanted = FALSE;
5160 DATA_BDAT: /* Common code for DATA and BDAT */
5161 #ifndef DISABLE_PIPE_CONNECT
5162 fl.pipe_connect_acceptable = FALSE;
5164 if (!discarded && recipients_count <= 0)
5166 if (fl.rcpt_smtp_response_same && rcpt_smtp_response)
5168 uschar *code = US"503";
5169 int len = Ustrlen(rcpt_smtp_response);
5170 smtp_respond(code, 3, SR_NOT_FINAL, US"All RCPT commands were rejected with "
5172 /* Responses from smtp_printf() will have \r\n on the end */
5173 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5174 rcpt_smtp_response[len-2] = 0;
5175 smtp_respond(code, 3, SR_NOT_FINAL, rcpt_smtp_response);
5177 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5178 smtp_printf("503 Valid RCPT command must precede %s\r\n", SP_NO_MORE,
5179 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5181 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5182 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5183 ? US"valid RCPT command must precede DATA"
5184 : US"valid RCPT command must precede BDAT");
5186 if (chunking_state > CHUNKING_OFFERED)
5188 bdat_push_receive_functions();
5194 if (toomany && recipients_max_reject)
5196 sender_address = NULL; /* This will allow a new MAIL without RSET */
5197 sender_address_unrewritten = NULL;
5198 smtp_printf("554 Too many recipients\r\n", SP_NO_MORE);
5200 if (chunking_state > CHUNKING_OFFERED)
5202 bdat_push_receive_functions();
5208 if (chunking_state > CHUNKING_OFFERED)
5209 rc = OK; /* There is no predata ACL or go-ahead output for BDAT */
5212 /* If there is a predata-ACL, re-check the synchronization afterwards,
5213 since the ACL may have delayed. To handle cutthrough delivery enforce a
5214 dummy call to get the DATA command sent. */
5216 GET_OPTION("acl_smtp_predata");
5217 if (!acl_smtp_predata && cutthrough.cctx.sock < 0)
5221 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5222 f.enable_dollar_recipients = TRUE;
5223 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5225 f.enable_dollar_recipients = FALSE;
5226 if (rc == OK && !check_sync())
5230 { /* Either the ACL failed the address, or it was deferred. */
5231 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5237 smtp_user_msg(US"354", user_msg);
5240 "354 Enter message, ending with \".\" on a line by itself\r\n", SP_NO_MORE);
5243 if (f.bdat_readers_wanted)
5244 bdat_push_receive_functions();
5247 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5248 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5249 US &on, sizeof(on));
5252 message_ended = END_NOTENDED; /* Indicate in middle of data */
5263 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5264 &start, &end, &recipient_domain, FALSE)))
5266 smtp_printf("501 %s\r\n", SP_NO_MORE, errmess);
5270 if (!recipient_domain)
5271 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5275 GET_OPTION("acl_smtp_vrfy");
5276 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5277 &user_msg, &log_msg)) != OK)
5278 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5282 address_item * addr = deliver_make_addr(address, FALSE);
5284 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5285 -1, -1, NULL, NULL, NULL))
5288 s = string_sprintf("250 <%s> is deliverable", address);
5292 s = (addr->user_message != NULL)?
5293 string_sprintf("451 <%s> %s", address, addr->user_message) :
5294 string_sprintf("451 Cannot resolve <%s> at this time", address);
5298 s = (addr->user_message != NULL)?
5299 string_sprintf("550 <%s> %s", address, addr->user_message) :
5300 string_sprintf("550 <%s> is not deliverable", address);
5301 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5302 smtp_cmd_argument, host_and_ident(TRUE));
5306 smtp_printf("%s\r\n", SP_NO_MORE, s);
5314 GET_OPTION("acl_smtp_expn");
5315 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5317 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5320 BOOL save_log_testing_mode = f.log_testing_mode;
5321 f.address_test_mode = f.log_testing_mode = TRUE;
5322 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5323 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5325 f.address_test_mode = FALSE;
5326 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5335 if (!fl.tls_advertised)
5337 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5338 US"STARTTLS command used when not advertised");
5342 /* Apply an ACL check if one is defined */
5344 GET_OPTION("acl_smtp_starttls");
5345 if ( acl_smtp_starttls
5346 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5347 &user_msg, &log_msg)) != OK
5350 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5354 /* RFC 2487 is not clear on when this command may be sent, though it
5355 does state that all information previously obtained from the client
5356 must be discarded if a TLS session is started. It seems reasonable to
5357 do an implied RSET when STARTTLS is received. */
5359 incomplete_transaction_log(US"STARTTLS");
5360 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5361 reset_point = smtp_reset(reset_point);
5363 cmd_list[CL_STLS].is_mail_cmd = FALSE;
5365 /* There's an attack where more data is read in past the STARTTLS command
5366 before TLS is negotiated, then assumed to be part of the secure session
5367 when used afterwards; we use segregated input buffers, so are not
5368 vulnerable, but we want to note when it happens and, for sheer paranoia,
5369 ensure that the buffer is "wiped".
5370 Pipelining sync checks will normally have protected us too, unless disabled
5371 by configuration. */
5376 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5377 if (tls_in.active.sock < 0)
5378 smtp_inend = smtp_inptr = smtp_inbuffer;
5379 /* and if TLS is already active, tls_server_start() should fail */
5382 /* There is nothing we value in the input buffer and if TLS is successfully
5383 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5384 fresh content into it. The buffer contains arbitrary content from an
5385 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5386 It seems safest to just wipe away the content rather than leave it as a
5387 target to jump to. */
5389 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5391 /* Attempt to start up a TLS session, and if successful, discard all
5392 knowledge that was obtained previously. At least, that's what the RFC says,
5393 and that's what happens by default. However, in order to work round YAEB,
5394 there is an option to remember the esmtp state. Sigh.
5396 We must allow for an extra EHLO command and an extra AUTH command after
5397 STARTTLS that don't add to the nonmail command count. */
5400 if ((rc = tls_server_start(&s)) == OK)
5402 if (!tls_remember_esmtp)
5403 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5404 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
5405 cmd_list[CL_AUTH].is_mail_cmd = TRUE;
5406 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
5407 if (sender_helo_name)
5409 sender_helo_name = NULL;
5410 host_build_sender_fullhost(); /* Rebuild */
5411 set_process_info("handling incoming TLS connection from %s",
5412 host_and_ident(FALSE));
5415 (sender_host_address ? protocols : protocols_local)
5417 ? pextend + (sender_host_authenticated ? pauthed : 0)
5419 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5422 sender_host_auth_pubname = sender_host_authenticated = NULL;
5423 authenticated_id = NULL;
5424 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5425 DEBUG(D_tls) debug_printf("TLS active\n");
5426 break; /* Successful STARTTLS */
5429 (void) smtp_log_tls_fail(s);
5431 /* Some local configuration problem was discovered before actually trying
5432 to do a TLS handshake; give a temporary error. */
5436 smtp_printf("454 TLS currently unavailable\r\n", SP_NO_MORE);
5440 /* Hard failure. Reject everything except QUIT or closed connection. One
5441 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5442 set, but we must still reject all incoming commands. Another is a handshake
5443 failure - and there may some encrypted data still in the pipe to us, which we
5444 see as garbage commands. */
5446 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5447 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5450 log_close_event(US"by EOF");
5451 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5455 /* It is perhaps arguable as to which exit ACL should be called here,
5456 but as it is probably a situation that almost never arises, it
5457 probably doesn't matter. We choose to call the real QUIT ACL, which in
5458 some sense is perhaps "right". */
5461 f.smtp_in_quit = TRUE;
5463 GET_OPTION("acl_smtp_quit");
5465 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5466 &log_msg)) == ERROR))
5467 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5470 smtp_respond(US"221", 3, SR_FINAL, user_msg);
5472 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
5473 log_close_event(US"by QUIT");
5478 smtp_printf("554 Security failure\r\n", SP_NO_MORE);
5481 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5486 /* The ACL for QUIT is provided for gathering statistical information or
5487 similar; it does not affect the response code, but it can supply a custom
5491 smtp_quit_handler(&user_msg, &log_msg);
5497 smtp_rset_handler();
5498 cancel_cutthrough_connection(TRUE, US"RSET received");
5499 reset_point = smtp_reset(reset_point);
5506 smtp_printf("250 OK\r\n", SP_NO_MORE);
5510 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5511 used, a check will be done for permitted hosts. Show STARTTLS only if not
5512 already in a TLS session and if it would be advertised in the EHLO
5517 smtp_printf("214-Commands supported:\r\n214", SP_MORE);
5518 smtp_printf(" AUTH", SP_MORE);
5520 if (tls_in.active.sock < 0 &&
5521 verify_check_host(&tls_advertise_hosts) != FAIL)
5522 smtp_printf(" STARTTLS", SP_MORE);
5524 smtp_printf(" HELO EHLO MAIL RCPT DATA BDAT", SP_MORE);
5525 smtp_printf(" NOOP QUIT RSET HELP", SP_MORE);
5526 if (acl_smtp_etrn) smtp_printf(" ETRN", SP_MORE);
5527 if (acl_smtp_expn) smtp_printf(" EXPN", SP_MORE);
5528 if (acl_smtp_vrfy) smtp_printf(" VRFY", SP_MORE);
5529 #ifndef DISABLE_WELLKNOWN
5530 if (verify_check_host(&wellknown_advertise_hosts) != FAIL)
5531 smtp_printf(" WELLKNOWN", SP_MORE);
5533 #ifdef EXPERIMENTAL_XCLIENT
5534 if (proxy_session || verify_check_host(&hosts_xclient) != FAIL)
5535 smtp_printf(" XCLIENT", SP_MORE);
5537 smtp_printf("\r\n", SP_NO_MORE);
5542 incomplete_transaction_log(US"connection lost");
5543 smtp_notquit_exit(US"connection-lost", US"421",
5544 US"%s lost input connection", smtp_active_hostname);
5546 /* Don't log by default unless in the middle of a message, as some mailers
5547 just drop the call rather than sending QUIT, and it clutters up the logs.
5550 if (sender_address || recipients_count > 0)
5551 log_write(L_lost_incoming_connection, LOG_MAIN,
5552 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5553 f.sender_host_unknown ? "EOF" : "disconnection",
5554 f.tcp_in_fastopen_logged
5557 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5559 host_and_ident(FALSE), smtp_read_error,
5560 string_timesince(&smtp_connection_start)
5564 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5565 smtp_get_connection_info(),
5566 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5568 string_timesince(&smtp_connection_start)
5579 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5580 US"ETRN is not permitted inside a transaction");
5584 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5585 host_and_ident(FALSE));
5587 GET_OPTION("acl_smtp_etrn");
5588 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5589 &user_msg, &log_msg)) != OK)
5591 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5595 /* Compute the serialization key for this command. */
5597 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5599 /* If a command has been specified for running as a result of ETRN, we
5600 permit any argument to ETRN. If not, only the # standard form is permitted,
5601 since that is strictly the only kind of ETRN that can be implemented
5602 according to the RFC. */
5604 GET_OPTION("smtp_etrn_command");
5605 if (smtp_etrn_command)
5609 etrn_command = smtp_etrn_command;
5610 deliver_domain = smtp_cmd_data;
5611 rc = transport_set_up_command(&argv, smtp_etrn_command, TSUC_EXPAND_ARGS, 0, NULL,
5612 US"ETRN processing", &error);
5613 deliver_domain = NULL;
5616 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5618 smtp_printf("458 Internal failure\r\n", SP_NO_MORE);
5623 /* Else set up to call Exim with the -R option. */
5627 if (*smtp_cmd_data++ != '#')
5629 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5630 US"argument must begin with #");
5633 etrn_command = US"exim -R";
5634 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5635 *queue_name ? 4 : 2,
5636 US"-R", smtp_cmd_data,
5637 US"-MCG", queue_name);
5640 /* If we are host-testing, don't actually do anything. */
5646 debug_printf("ETRN command is: %s\n", etrn_command);
5647 debug_printf("ETRN command execution skipped\n");
5649 if (user_msg == NULL) smtp_printf("250 OK\r\n", SP_NO_MORE);
5650 else smtp_user_msg(US"250", user_msg);
5655 /* If ETRN queue runs are to be serialized, check the database to
5656 ensure one isn't already running. */
5658 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5660 smtp_printf("458 Already processing %s\r\n", SP_NO_MORE, smtp_cmd_data);
5664 /* Fork a child process and run the command. We don't want to have to
5665 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5666 forking. It should be set that way anyway for external incoming SMTP,
5667 but we save and restore to be tidy. If serialization is required, we
5668 actually run the command in yet another process, so we can wait for it
5669 to complete and then remove the serialization lock. */
5671 oldsignal = signal(SIGCHLD, SIG_IGN);
5673 if ((pid = exim_fork(US"etrn-command")) == 0)
5675 smtp_input = FALSE; /* This process is not associated with the */
5676 (void)fclose(smtp_in); /* SMTP call any more. */
5677 (void)fclose(smtp_out);
5679 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5681 /* If not serializing, do the exec right away. Otherwise, fork down
5682 into another process. */
5684 if ( !smtp_etrn_serialize
5685 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5687 DEBUG(D_exec) debug_print_argv(argv);
5688 exim_nullstd(); /* Ensure std{in,out,err} exist */
5689 /* argv[0] should be untainted, from child_exec_exim() */
5690 execv(CS argv[0], (char *const *)argv);
5691 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5692 etrn_command, strerror(errno));
5693 _exit(EXIT_FAILURE); /* paranoia */
5696 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5697 is, we are in the first subprocess, after forking again. All we can do
5698 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5699 complete, before removing the serialization. */
5702 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5703 "failed: %s", strerror(errno));
5707 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5709 (void)wait(&status);
5710 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5714 enq_end(etrn_serialize_key);
5715 exim_underbar_exit(EXIT_SUCCESS);
5718 /* Back in the top level SMTP process. Check that we started a subprocess
5719 and restore the signal state. */
5723 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5725 smtp_printf("458 Unable to fork process\r\n", SP_NO_MORE);
5726 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5730 smtp_printf("250 OK\r\n", SP_NO_MORE);
5732 smtp_user_msg(US"250", user_msg);
5734 signal(SIGCHLD, oldsignal);
5739 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5740 US"unexpected argument data");
5744 /* This currently happens only for NULLs, but could be extended. */
5747 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5748 US"NUL character(s) present (shown as '?')");
5749 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5757 unsigned nchars = 150;
5758 uschar * buf = receive_getbuf(&nchars); /* destructive read */
5760 incomplete_transaction_log(US"sync failure");
5761 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5762 "(next input sent too soon: pipelining was%s advertised): "
5763 "rejected \"%s\" %s next input=\"%s\" (%u bytes)",
5764 f.smtp_in_pipelining_advertised ? "" : " not",
5765 smtp_cmd_buffer, host_and_ident(TRUE),
5766 string_printing(buf), nchars);
5767 smtp_notquit_exit(US"synchronization-error", US"554",
5768 US"SMTP synchronization error");
5769 done = 1; /* Pretend eof - drops connection */
5774 case TOO_MANY_NONMAIL_CMD:
5775 s = smtp_cmd_buffer;
5777 incomplete_transaction_log(US"too many non-mail commands");
5778 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5779 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5780 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5781 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5782 done = 1; /* Pretend eof - drops connection */
5785 #ifdef SUPPORT_PROXY
5786 case PROXY_FAIL_IGNORE_CMD:
5787 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", SP_NO_MORE);
5792 if (unknown_command_count++ >= smtp_max_unknown_commands)
5794 log_write(L_smtp_syntax_error, LOG_MAIN,
5795 "SMTP syntax error in \"%s\" %s %s",
5796 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5797 US"unrecognized command");
5798 incomplete_transaction_log(US"unrecognized command");
5799 smtp_notquit_exit(US"bad-commands", US"500",
5800 US"Too many unrecognized commands");
5802 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5803 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5804 string_printing(smtp_cmd_buffer));
5807 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5808 US"unrecognized command");
5812 /* This label is used by goto's inside loops that want to break out to
5813 the end of the command-processing loop. */
5816 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5817 last_was_rcpt = was_rcpt; /* protocol error handling */
5820 return done - 2; /* Convert yield values */
5826 authres_smtpauth(gstring * g)
5828 if (!sender_host_authenticated)
5831 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5833 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
5834 g = authenticated_id
5835 ? string_append(g, 2, US") x509.auth=", authenticated_id)
5836 : string_cat(g, US") reason=x509.auth");
5838 g = authenticated_id
5839 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
5840 : string_cat(g, US", no id saved)");
5842 if (authenticated_sender)
5843 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5851 /* End of smtp_in.c */