1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) The Exim Maintainers 2020 - 2023 */
6 /* Copyright (c) University of Cambridge 1995 - 2018 */
7 /* See the file NOTICE for conditions of use and distribution. */
8 /* SPDX-License-Identifier: GPL-2.0-or-later */
10 /* Functions for handling an incoming SMTP call. */
17 /* Initialize for TCP wrappers if so configured. It appears that the macro
18 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
19 including that header, and restore its value afterwards. */
21 #ifdef USE_TCP_WRAPPERS
24 #define EXIM_HAVE_IPV6
30 #define HAVE_IPV6 TRUE
33 int allow_severity = LOG_INFO;
34 int deny_severity = LOG_NOTICE;
35 uschar *tcp_wrappers_name;
39 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
40 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
41 commands that accept arguments, and this in particular applies to AUTH, where
42 the data can be quite long. More recently this value was 2048 in Exim;
43 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
44 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
45 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
46 we need room to handle large base64-encoded AUTHs for GSSAPI.
49 #define SMTP_CMD_BUFFER_SIZE 16384
51 /* Size of buffer for reading SMTP incoming packets */
53 #define IN_BUFFER_SIZE 8192
55 /* Structure for SMTP command list */
62 short int is_mail_cmd;
65 /* Codes for identifying commands. We order them so that those that come first
66 are those for which synchronization is always required. Checking this can help
70 /* These commands are required to be synchronized, i.e. to be the last in a
71 block of commands when pipelining. */
73 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
74 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
75 ETRN_CMD, /* This by analogy with TURN from the RFC */
76 STARTTLS_CMD, /* Required by the STARTTLS RFC */
77 TLS_AUTH_CMD, /* auto-command at start of SSL */
78 #ifdef EXPERIMENTAL_XCLIENT
79 XCLIENT_CMD, /* per xlexkiro implementation */
82 /* This is a dummy to identify the non-sync commands when pipelining */
84 NON_SYNC_CMD_PIPELINING,
86 /* These commands need not be synchronized when pipelining */
88 MAIL_CMD, RCPT_CMD, RSET_CMD,
90 /* This is a dummy to identify the non-sync commands when not pipelining */
92 NON_SYNC_CMD_NON_PIPELINING,
94 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
95 processed the message is sent using a series of BDAT commands"
96 implies that BDAT should be synchronized. However, we see Google, at least,
97 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
98 processing of the RCPT response(s). We shall do the same, and not require
99 synch for BDAT. Worse, as the chunk may (very likely will) follow the
100 command-header in the same packet we cannot do the usual "is there any
101 follow-on data after the command line" even for non-pipeline mode.
102 So we'll need an explicit check after reading the expected chunk amount
103 when non-pipe, before sending the ACK. */
107 /* I have been unable to find a statement about the use of pipelining
108 with AUTH, so to be on the safe side it is here, though I kind of feel
109 it should be up there with the synchronized commands. */
113 /* I'm not sure about these, but I don't think they matter. */
118 PROXY_FAIL_IGNORE_CMD,
121 /* These are specials that don't correspond to actual commands */
123 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
124 TOO_MANY_NONMAIL_CMD };
127 /* This is a convenience macro for adding the identity of an SMTP command
128 to the circular buffer that holds a list of the last n received. */
131 smtp_connection_had[smtp_ch_index++] = n; \
132 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
135 /*************************************************
136 * Local static variables *
137 *************************************************/
140 BOOL auth_advertised :1;
142 BOOL tls_advertised :1;
144 BOOL dsn_advertised :1;
146 BOOL helo_verify_required :1;
149 BOOL helo_accept_junk :1;
150 #ifndef DISABLE_PIPE_CONNECT
151 BOOL pipe_connect_acceptable :1;
153 BOOL rcpt_smtp_response_same :1;
154 BOOL rcpt_in_progress :1;
155 BOOL smtp_exit_function_called :1;
157 BOOL smtputf8_advertised :1;
160 .helo_verify_required = FALSE,
161 .helo_verify = FALSE,
162 .smtp_exit_function_called = FALSE,
165 static auth_instance *authenticated_by;
166 static int count_nonmail;
167 static int nonmail_command_count;
168 static int synprot_error_count;
169 static int unknown_command_count;
170 static int sync_cmd_limit;
171 static int smtp_write_error = 0;
173 static uschar *rcpt_smtp_response;
174 static uschar *smtp_data_buffer;
175 static uschar *smtp_cmd_data;
177 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
178 final fields of all except AUTH are forced TRUE at the start of a new message
179 setup, to allow one of each between messages that is not counted as a nonmail
180 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
181 allow a new EHLO after starting up TLS.
183 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
184 counted. However, the flag is changed when AUTH is received, so that multiple
185 failing AUTHs will eventually hit the limit. After a successful AUTH, another
186 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
187 forced TRUE, to allow for the re-authentication that can happen at that point.
189 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
190 count of non-mail commands and possibly provoke an error.
192 tls_auth is a pseudo-command, never expected in input. It is activated
193 on TLS startup and looks for a tls authenticator. */
204 #ifdef EXPERIMENTAL_XCLIENT
209 static smtp_cmd_list cmd_list[] = {
210 /* name len cmd has_arg is_mail_cmd */
212 [CL_RSET] = { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
213 [CL_HELO] = { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
214 [CL_EHLO] = { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
215 [CL_AUTH] = { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
217 [CL_STLS] = { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
218 [CL_TLAU] = { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
220 #ifdef EXPERIMENTAL_XCLIENT
221 [CL_XCLI] = { "xclient", sizeof("xclient")-1, XCLIENT_CMD, TRUE, FALSE },
224 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
225 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
226 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
227 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
228 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
229 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
230 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
231 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
232 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
233 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
236 /* This list of names is used for performing the smtp_no_mail logging action. */
238 uschar * smtp_names[] =
240 [SCH_NONE] = US"NONE",
241 [SCH_AUTH] = US"AUTH",
242 [SCH_DATA] = US"DATA",
243 [SCH_BDAT] = US"BDAT",
244 [SCH_EHLO] = US"EHLO",
245 [SCH_ETRN] = US"ETRN",
246 [SCH_EXPN] = US"EXPN",
247 [SCH_HELO] = US"HELO",
248 [SCH_HELP] = US"HELP",
249 [SCH_MAIL] = US"MAIL",
250 [SCH_NOOP] = US"NOOP",
251 [SCH_QUIT] = US"QUIT",
252 [SCH_RCPT] = US"RCPT",
253 [SCH_RSET] = US"RSET",
254 [SCH_STARTTLS] = US"STARTTLS",
255 [SCH_VRFY] = US"VRFY",
256 #ifdef EXPERIMENTAL_XCLIENT
257 [SCH_XCLIENT] = US"XCLIENT",
261 static uschar *protocols_local[] = {
262 US"local-smtp", /* HELO */
263 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
264 US"local-esmtp", /* EHLO */
265 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
266 US"local-esmtpa", /* EHLO->AUTH */
267 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
269 static uschar *protocols[] = {
271 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
272 US"esmtp", /* EHLO */
273 US"esmtps", /* EHLO->STARTTLS->EHLO */
274 US"esmtpa", /* EHLO->AUTH */
275 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
280 #define pcrpted 1 /* added to pextend or pnormal */
281 #define pauthed 2 /* added to pextend */
283 /* Sanity check and validate optional args to MAIL FROM: envelope */
286 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
290 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
296 uschar * name; /* option requested during MAIL cmd */
297 int value; /* enum type */
298 BOOL need_value; /* TRUE requires value (name=value pair format)
299 FALSE is a singleton */
301 static env_mail_type_t env_mail_type_list[] = {
302 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
303 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
304 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
306 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
308 { US"RET", ENV_MAIL_OPT_RET, TRUE },
309 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
311 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
313 /* keep this the last entry */
314 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
317 /* When reading SMTP from a remote host, we have to use our own versions of the
318 C input-reading functions, in order to be able to flush the SMTP output only
319 when about to read more data from the socket. This is the only way to get
320 optimal performance when the client is using pipelining. Flushing for every
321 command causes a separate packet and reply packet each time; saving all the
322 responses up (when pipelining) combines them into one packet and one response.
324 For simplicity, these functions are used for *all* SMTP input, not only when
325 receiving over a socket. However, after setting up a secure socket (SSL), input
326 is read via the OpenSSL library, and another set of functions is used instead
329 These functions are set in the receive_getc etc. variables and called with the
330 same interface as the C functions. However, since there can only ever be
331 one incoming SMTP call, we just use a single buffer and flags. There is no need
332 to implement a complicated private FILE-like structure.*/
334 static uschar *smtp_inbuffer;
335 static uschar *smtp_inptr;
336 static uschar *smtp_inend;
337 static int smtp_had_eof;
338 static int smtp_had_error;
341 /* forward declarations */
342 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
343 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
344 static void smtp_quit_handler(uschar **, uschar **);
345 static void smtp_rset_handler(void);
347 /*************************************************
348 * Log incomplete transactions *
349 *************************************************/
351 /* This function is called after a transaction has been aborted by RSET, QUIT,
352 connection drops or other errors. It logs the envelope information received
353 so far in order to preserve address verification attempts.
355 Argument: string to indicate what aborted the transaction
360 incomplete_transaction_log(uschar * what)
362 if (!sender_address /* No transaction in progress */
363 || !LOGGING(smtp_incomplete_transaction))
366 /* Build list of recipients for logging */
368 if (recipients_count > 0)
370 raw_recipients = store_get(recipients_count * sizeof(uschar *), GET_UNTAINTED);
371 for (int i = 0; i < recipients_count; i++)
372 raw_recipients[i] = recipients_list[i].address;
373 raw_recipients_count = recipients_count;
376 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
377 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
383 log_close_event(const uschar * reason)
385 log_write(L_smtp_connection, LOG_MAIN, "%s D=%s closed %s",
386 smtp_get_connection_info(), string_timesince(&smtp_connection_start), reason);
391 smtp_command_timeout_exit(void)
393 log_write(L_lost_incoming_connection,
394 LOG_MAIN, "SMTP command timeout on%s connection from %s D=%s",
395 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE),
396 string_timesince(&smtp_connection_start));
397 if (smtp_batched_input)
398 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
399 smtp_notquit_exit(US"command-timeout", US"421",
400 US"%s: SMTP command timeout - closing connection",
401 smtp_active_hostname);
402 exim_exit(EXIT_FAILURE);
406 smtp_command_sigterm_exit(void)
408 log_close_event(US"after SIGTERM");
409 if (smtp_batched_input)
410 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
411 smtp_notquit_exit(US"signal-exit", US"421",
412 US"%s: Service not available - closing connection", smtp_active_hostname);
413 exim_exit(EXIT_FAILURE);
417 smtp_data_timeout_exit(void)
419 log_write(L_lost_incoming_connection, LOG_MAIN,
420 "SMTP data timeout (message abandoned) on connection from %s F=<%s> D=%s",
421 sender_fullhost ? sender_fullhost : US"local process", sender_address,
422 string_timesince(&smtp_connection_start));
423 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
424 /* Does not return */
428 smtp_data_sigint_exit(void)
430 log_close_event(had_data_sigint == SIGTERM ? US"SIGTERM":US"SIGINT");
431 receive_bomb_out(US"signal-exit",
432 US"Service not available - SIGTERM or SIGINT received");
433 /* Does not return */
437 /******************************************************************************/
438 /* SMTP input buffer handling. Most of these are similar to stdio routines. */
443 /* Set up the buffer for inputting using direct read() calls, and arrange to
444 call the local functions instead of the standard C ones. Place a NUL at the
445 end of the buffer to safety-stop C-string reads from it. */
447 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
448 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
449 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
451 smtp_inptr = smtp_inend = smtp_inbuffer;
452 smtp_had_eof = smtp_had_error = 0;
457 /* Refill the buffer, and notify DKIM verification code.
458 Return false for error or EOF.
462 smtp_refill(unsigned lim)
466 if (!smtp_out) return FALSE;
468 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
470 /* Limit amount read, so non-message data is not fed to DKIM.
471 Take care to not touch the safety NUL at the end of the buffer. */
473 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
475 if (smtp_receive_timeout > 0) ALARM_CLR(0);
478 /* Must put the error text in fixed store, because this might be during
479 header reading, where it releases unused store above the header. */
482 if (had_command_timeout) /* set by signal handler */
483 smtp_command_timeout_exit(); /* does not return */
484 if (had_command_sigterm)
485 smtp_command_sigterm_exit();
486 if (had_data_timeout)
487 smtp_data_timeout_exit();
489 smtp_data_sigint_exit();
491 smtp_had_error = save_errno;
492 smtp_read_error = string_copy_perm(
493 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
500 dkim_exim_verify_feed(smtp_inbuffer, rc);
502 smtp_inend = smtp_inbuffer + rc;
503 smtp_inptr = smtp_inbuffer;
508 /* Check if there is buffered data */
513 return smtp_inptr < smtp_inend;
516 /* SMTP version of getc()
518 This gets the next byte from the SMTP input buffer. If the buffer is empty,
519 it flushes the output, and refills the buffer, with a timeout. The signal
520 handler is set appropriately by the calling function. This function is not used
521 after a connection has negotiated itself into an TLS/SSL state.
523 Arguments: lim Maximum amount to read/buffer
524 Returns: the next character or EOF
528 smtp_getc(unsigned lim)
530 if (!smtp_hasc() && !smtp_refill(lim)) return EOF;
531 return *smtp_inptr++;
534 /* Get many bytes, refilling buffer if needed */
537 smtp_getbuf(unsigned * len)
542 if (!smtp_hasc() && !smtp_refill(*len))
543 { *len = 0; return NULL; }
545 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
552 /* Copy buffered data to the dkim feed.
553 Called, unless TLS, just before starting to read message headers. */
556 smtp_get_cache(unsigned lim)
559 int n = smtp_inend - smtp_inptr;
563 dkim_exim_verify_feed(smtp_inptr, n);
568 /* SMTP version of ungetc()
569 Puts a character back in the input buffer. Only ever called once.
574 Returns: the character
580 if (smtp_inptr <= smtp_inbuffer) /* NB: NOT smtp_hasc() ! */
581 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "buffer underflow in smtp_ungetc");
588 /* SMTP version of feof()
589 Tests for a previous EOF
592 Returns: non-zero if the eof flag is set
602 /* SMTP version of ferror()
603 Tests for a previous read error, and returns with errno
604 restored to what it was when the error was detected.
607 Returns: non-zero if the error flag is set
613 errno = smtp_had_error;
614 return smtp_had_error;
618 /* Check if a getc will block or not */
621 smtp_could_getc(void)
625 struct timeval tzero = {.tv_sec = 0, .tv_usec = 0};
627 if (smtp_inptr < smtp_inend)
630 fd = fileno(smtp_in);
633 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
635 if (rc <= 0) return FALSE; /* Not ready to read */
636 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
637 if (rc < 0) return FALSE; /* End of file or error */
644 /******************************************************************************/
645 /*************************************************
646 * Recheck synchronization *
647 *************************************************/
649 /* Synchronization checks can never be perfect because a packet may be on its
650 way but not arrived when the check is done. Normally, the checks happen when
651 commands are read: Exim ensures that there is no more input in the input buffer.
652 In normal cases, the response to the command will be fast, and there is no
655 However, for some commands an ACL is run, and that can include delays. In those
656 cases, it is useful to do another check on the input just before sending the
657 response. This also applies at the start of a connection. This function does
658 that check by means of the select() function, as long as the facility is not
659 disabled or inappropriate. A failure of select() is ignored.
661 When there is unwanted input, we read it so that it appears in the log of the
665 Returns: TRUE if all is well; FALSE if there is input pending
669 wouldblock_reading(void)
672 if (tls_in.active.sock >= 0)
673 return !tls_could_getc();
676 return !smtp_could_getc();
682 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
685 return wouldblock_reading();
689 /******************************************************************************/
690 /* Variants of the smtp_* input handling functions for use in CHUNKING mode */
692 /* Forward declarations */
693 static inline void bdat_push_receive_functions(void);
694 static inline void bdat_pop_receive_functions(void);
697 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
698 previous BDAT chunk and getting new ones when we run out. Uses the
699 underlying smtp_getc or tls_getc both for that and for getting the
700 (buffered) data byte. EOD signals (an expected) no further data.
701 ERR signals a protocol error, and EOF a closed input stream.
703 Called from read_bdat_smtp() in receive.c for the message body, but also
704 by the headers read loop in receive_msg(); manipulates chunking_state
705 to handle the BDAT command/response.
706 Placed here due to the correlation with the above smtp_getc(), which it wraps,
707 and also by the need to do smtp command/response handling.
709 Arguments: lim (ignored)
710 Returns: the next character or ERR, EOD or EOF
714 bdat_getc(unsigned lim)
716 uschar * user_msg = NULL;
725 if (chunking_data_left > 0)
726 return lwr_receive_getc(chunking_data_left--);
728 bdat_pop_receive_functions();
730 dkim_save = dkim_collect_input;
731 dkim_collect_input = 0;
734 /* Unless PIPELINING was offered, there should be no next command
735 until after we ack that chunk */
737 if (!f.smtp_in_pipelining_advertised && !check_sync())
739 unsigned n = smtp_inend - smtp_inptr;
742 incomplete_transaction_log(US"sync failure");
743 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
744 "(next input sent too soon: pipelining was not advertised): "
745 "rejected \"%s\" %s next input=\"%s\"%s",
746 smtp_cmd_buffer, host_and_ident(TRUE),
747 string_printing(string_copyn(smtp_inptr, n)),
748 smtp_inend - smtp_inptr > n ? "..." : "");
749 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
750 US"SMTP synchronization error");
751 goto repeat_until_rset;
754 /* If not the last, ack the received chunk. The last response is delayed
755 until after the data ACL decides on it */
757 if (chunking_state == CHUNKING_LAST)
760 dkim_collect_input = dkim_save;
761 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
762 dkim_collect_input = 0;
767 smtp_printf("250 %u byte chunk received\r\n", SP_NO_MORE, chunking_datasize);
768 chunking_state = CHUNKING_OFFERED;
769 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
771 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
772 QUIT, RSET or NOOP but handling them seems obvious */
775 switch(smtp_read_command(TRUE, 1))
778 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
779 US"only BDAT permissible after non-LAST BDAT");
782 switch(smtp_read_command(TRUE, 1))
784 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
785 case EOF_CMD: return EOF;
786 case RSET_CMD: smtp_rset_handler(); return ERR;
787 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
788 US"only RSET accepted now") > 0)
790 goto repeat_until_rset;
794 smtp_quit_handler(&user_msg, &log_msg);
805 smtp_printf("250 OK\r\n", SP_NO_MORE);
812 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
814 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
815 US"missing size for BDAT command");
818 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
819 ? CHUNKING_LAST : CHUNKING_ACTIVE;
820 chunking_data_left = chunking_datasize;
821 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
822 (int)chunking_state, chunking_data_left);
824 if (chunking_datasize == 0)
825 if (chunking_state == CHUNKING_LAST)
829 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
830 US"zero size for BDAT command");
831 goto repeat_until_rset;
834 bdat_push_receive_functions();
836 dkim_collect_input = dkim_save;
838 break; /* to top of main loop */
847 if (chunking_data_left > 0)
848 return lwr_receive_hasc();
853 bdat_getbuf(unsigned * len)
857 if (chunking_data_left <= 0)
858 { *len = 0; return NULL; }
860 if (*len > chunking_data_left) *len = chunking_data_left;
861 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
862 chunking_data_left -= *len;
867 bdat_flush_data(void)
869 while (chunking_data_left)
871 unsigned n = chunking_data_left;
872 if (!bdat_getbuf(&n)) break;
875 bdat_pop_receive_functions();
876 chunking_state = CHUNKING_OFFERED;
877 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
882 bdat_push_receive_functions(void)
884 /* push the current receive_* function on the "stack", and
885 replace them by bdat_getc(), which in turn will use the lwr_receive_*
886 functions to do the dirty work. */
887 if (!lwr_receive_getc)
889 lwr_receive_getc = receive_getc;
890 lwr_receive_getbuf = receive_getbuf;
891 lwr_receive_hasc = receive_hasc;
892 lwr_receive_ungetc = receive_ungetc;
896 DEBUG(D_receive) debug_printf("chunking double-push receive functions\n");
899 receive_getc = bdat_getc;
900 receive_getbuf = bdat_getbuf;
901 receive_hasc = bdat_hasc;
902 receive_ungetc = bdat_ungetc;
906 bdat_pop_receive_functions(void)
908 if (!lwr_receive_getc)
910 DEBUG(D_receive) debug_printf("chunking double-pop receive functions\n");
913 receive_getc = lwr_receive_getc;
914 receive_getbuf = lwr_receive_getbuf;
915 receive_hasc = lwr_receive_hasc;
916 receive_ungetc = lwr_receive_ungetc;
918 lwr_receive_getc = NULL;
919 lwr_receive_getbuf = NULL;
920 lwr_receive_hasc = NULL;
921 lwr_receive_ungetc = NULL;
927 chunking_data_left++;
928 bdat_push_receive_functions(); /* we're not done yet, calling push is safe, because it checks the state before pushing anything */
929 return lwr_receive_ungetc(ch);
934 /******************************************************************************/
936 /*************************************************
937 * Write formatted string to SMTP channel *
938 *************************************************/
940 /* This is a separate function so that we don't have to repeat everything for
941 TLS support or debugging. It is global so that the daemon and the
942 authentication functions can use it. It does not return any error indication,
943 because major problems such as dropped connections won't show up till an output
944 flush for non-TLS connections. The smtp_fflush() function is available for
945 checking that: for convenience, TLS output errors are remembered here so that
946 they are also picked up later by smtp_fflush().
948 This function is exposed to the local_scan API; do not change the signature.
952 more further data expected
953 ... optional arguments
959 smtp_printf(const char *format, BOOL more, ...)
964 smtp_vprintf(format, more, ap);
968 /* This is split off so that verify.c:respond_printf() can, in effect, call
969 smtp_printf(), bearing in mind that in C a vararg function can't directly
970 call another vararg function, only a function which accepts a va_list.
972 This function is exposed to the local_scan API; do not change the signature.
974 /*XXX consider passing caller-info in, for string_vformat-onward */
977 smtp_vprintf(const char *format, BOOL more, va_list ap)
979 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
982 /* Use taint-unchecked routines for writing into big_buffer, trusting
983 that we'll never expand it. */
985 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
986 string_from_gstring(&gs);
988 DEBUG(D_receive) for (const uschar * t, * s = gs.s;
989 s && (t = Ustrchr(s, '\r'));
990 s = t + 2) /* \r\n */
991 debug_printf("%s %.*s\n",
992 s == gs.s ? "SMTP>>" : " ",
997 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
998 smtp_closedown(US"Unexpected error");
999 exim_exit(EXIT_FAILURE);
1002 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
1003 have had the same. Note: this code is also present in smtp_respond(). It would
1004 be tidier to have it only in one place, but when it was added, it was easier to
1005 do it that way, so as not to have to mess with the code for the RCPT command,
1006 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
1008 if (fl.rcpt_in_progress)
1010 if (!rcpt_smtp_response)
1011 rcpt_smtp_response = string_copy(big_buffer);
1012 else if (fl.rcpt_smtp_response_same &&
1013 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
1014 fl.rcpt_smtp_response_same = FALSE;
1015 fl.rcpt_in_progress = FALSE;
1018 /* Now write the string */
1022 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
1024 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
1026 smtp_write_error = -1;
1031 /*************************************************
1032 * Flush SMTP out and check for error *
1033 *************************************************/
1035 /* This function isn't currently used within Exim (it detects errors when it
1036 tries to read the next SMTP input), but is available for use in local_scan().
1037 It flushes the output and checks for errors.
1040 Returns: 0 for no error; -1 after an error
1046 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
1050 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
1052 (fflush(smtp_out) != 0)
1054 smtp_write_error = -1;
1056 return smtp_write_error;
1061 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
1062 a reponse with the one following. */
1065 pipeline_response(void)
1067 if ( !smtp_enforce_sync || !sender_host_address
1068 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
1071 if (wouldblock_reading()) return FALSE;
1072 f.smtp_in_pipelining_used = TRUE;
1077 #ifndef DISABLE_PIPE_CONNECT
1079 pipeline_connect_sends(void)
1081 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
1084 if (wouldblock_reading()) return FALSE;
1085 f.smtp_in_early_pipe_used = TRUE;
1090 /*************************************************
1091 * SMTP command read timeout *
1092 *************************************************/
1094 /* Signal handler for timing out incoming SMTP commands. This attempts to
1097 Argument: signal number (SIGALRM)
1102 command_timeout_handler(int sig)
1104 had_command_timeout = sig;
1109 /*************************************************
1110 * SIGTERM received *
1111 *************************************************/
1113 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1115 Argument: signal number (SIGTERM)
1120 command_sigterm_handler(int sig)
1122 had_command_sigterm = sig;
1128 /*************************************************
1129 * Read one command line *
1130 *************************************************/
1132 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1133 There are sites that don't do this, and in any case internal SMTP probably
1134 should check only for LF. Consequently, we check here for LF only. The line
1135 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1136 an unknown command. The command is read into the global smtp_cmd_buffer so that
1137 it is available via $smtp_command.
1139 The character reading routine sets up a timeout for each block actually read
1140 from the input (which may contain more than one command). We set up a special
1141 signal handler that closes down the session on a timeout. Control does not
1142 return when it runs.
1145 check_sync if TRUE, check synchronization rules if global option is TRUE
1146 buffer_lim maximum to buffer in lower layer
1148 Returns: a code identifying the command (enumerated above)
1152 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1156 BOOL hadnull = FALSE;
1158 had_command_timeout = 0;
1159 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1161 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1163 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1165 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1173 smtp_cmd_buffer[ptr++] = c;
1176 receive_linecount++; /* For BSMTP errors */
1177 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1179 /* If hit end of file, return pseudo EOF command. Whether we have a
1180 part-line already read doesn't matter, since this is an error state. */
1182 if (c == EOF) return EOF_CMD;
1184 /* Remove any CR and white space at the end of the line, and terminate the
1187 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1188 smtp_cmd_buffer[ptr] = 0;
1190 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1192 /* NULLs are not allowed in SMTP commands */
1194 if (hadnull) return BADCHAR_CMD;
1196 /* Scan command list and return identity, having set the data pointer
1197 to the start of the actual data characters. Check for SMTP synchronization
1200 for (smtp_cmd_list * p = cmd_list; p < cmd_list + nelem(cmd_list); p++)
1202 #ifdef SUPPORT_PROXY
1203 /* Only allow QUIT command if Proxy Protocol parsing failed */
1204 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1208 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1209 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1210 || smtp_cmd_buffer[p->len] == 0
1211 || smtp_cmd_buffer[p->len] == ' '
1214 if ( smtp_inptr < smtp_inend /* Outstanding input */
1215 && p->cmd < sync_cmd_limit /* Command should sync */
1216 && check_sync /* Local flag set */
1217 && smtp_enforce_sync /* Global flag set */
1218 && sender_host_address != NULL /* Not local input */
1219 && !f.sender_host_notsocket /* Really is a socket */
1223 /* The variables $smtp_command and $smtp_command_argument point into the
1224 unmodified input buffer. A copy of the latter is taken for actual
1225 processing, so that it can be chopped up into separate parts if necessary,
1226 for example, when processing a MAIL command options such as SIZE that can
1227 follow the sender address. */
1229 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1230 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1231 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1232 smtp_cmd_data = smtp_data_buffer;
1234 /* Count non-mail commands from those hosts that are controlled in this
1235 way. The default is all hosts. We don't waste effort checking the list
1236 until we get a non-mail command, but then cache the result to save checking
1237 again. If there's a DEFER while checking the host, assume it's in the list.
1239 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1240 start of each incoming message by fiddling with the value in the table. */
1242 if (!p->is_mail_cmd)
1244 if (count_nonmail == TRUE_UNSET) count_nonmail =
1245 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1246 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1247 return TOO_MANY_NONMAIL_CMD;
1250 /* If there is data for a command that does not expect it, generate the
1253 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1257 #ifdef SUPPORT_PROXY
1258 /* Only allow QUIT command if Proxy Protocol parsing failed */
1259 if (proxy_session && f.proxy_session_failed)
1260 return PROXY_FAIL_IGNORE_CMD;
1263 /* Enforce synchronization for unknown commands */
1265 if ( smtp_inptr < smtp_inend /* Outstanding input */
1266 && check_sync /* Local flag set */
1267 && smtp_enforce_sync /* Global flag set */
1268 && sender_host_address /* Not local input */
1269 && !f.sender_host_notsocket /* Really is a socket */
1279 /*************************************************
1280 * Forced closedown of call *
1281 *************************************************/
1283 /* This function is called from log.c when Exim is dying because of a serious
1284 disaster, and also from some other places. If an incoming non-batched SMTP
1285 channel is open, it swallows the rest of the incoming message if in the DATA
1286 phase, sends the reply string, and gives an error to all subsequent commands
1287 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1291 message SMTP reply string to send, excluding the code
1297 smtp_closedown(uschar * message)
1299 if (!smtp_in || smtp_batched_input) return;
1300 receive_swallow_smtp();
1301 smtp_printf("421 %s\r\n", SP_NO_MORE, message);
1303 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1309 f.smtp_in_quit = TRUE;
1310 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
1315 smtp_printf("250 Reset OK\r\n", SP_NO_MORE);
1319 smtp_printf("421 %s\r\n", SP_NO_MORE, message);
1327 /*************************************************
1328 * Set up connection info for logging *
1329 *************************************************/
1331 /* This function is called when logging information about an SMTP connection.
1332 It sets up appropriate source information, depending on the type of connection.
1333 If sender_fullhost is NULL, we are at a very early stage of the connection;
1334 just use the IP address.
1337 Returns: a string describing the connection
1341 smtp_get_connection_info(void)
1343 const uschar * hostname = sender_fullhost
1344 ? sender_fullhost : sender_host_address;
1345 gstring * g = string_catn(NULL, US"SMTP connection", 15);
1347 if (LOGGING(connection_id))
1348 g = string_fmt_append(g, " Ci=%lu", connection_id);
1349 g = string_catn(g, US" from ", 6);
1352 g = string_cat(g, hostname);
1354 else if (f.sender_host_unknown || f.sender_host_notsocket)
1355 g = string_cat(g, sender_ident ? sender_ident : US"NULL");
1357 else if (f.is_inetd)
1358 g = string_append(g, 2, hostname, US" (via inetd)");
1360 else if (LOGGING(incoming_interface) && interface_address)
1361 g = string_fmt_append(g, "%s I=[%s]:%d", hostname, interface_address, interface_port);
1364 g = string_cat(g, hostname);
1366 gstring_release_unused(g);
1367 return string_from_gstring(g);
1373 /* Append TLS-related information to a log line
1376 g String under construction: allocated string to extend, or NULL
1378 Returns: Allocated string or NULL
1381 s_tlslog(gstring * g)
1383 if (LOGGING(tls_cipher) && tls_in.cipher)
1385 g = string_append(g, 2, US" X=", tls_in.cipher);
1386 #ifndef DISABLE_TLS_RESUME
1387 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1388 g = string_catn(g, US"*", 1);
1391 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1392 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1393 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1394 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1395 if (LOGGING(tls_sni) && tls_in.sni)
1396 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1404 s_connhad_log(gstring * g)
1406 const uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1407 ? US" C=..." : US" C=";
1409 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1410 if (smtp_connection_had[i] != SCH_NONE)
1412 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1415 for (int i = 0; i < smtp_ch_index; i++, sep = US",")
1416 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1421 /*************************************************
1422 * Log lack of MAIL if so configured *
1423 *************************************************/
1425 /* This function is called when an SMTP session ends. If the log selector
1426 smtp_no_mail is set, write a log line giving some details of what has happened
1427 in the SMTP session.
1434 smtp_log_no_mail(void)
1439 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1442 if (sender_host_authenticated)
1444 g = string_append(g, 2, US" A=", sender_host_authenticated);
1445 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1452 g = s_connhad_log(g);
1454 if (!(s = string_from_gstring(g))) s = US"";
1456 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1457 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1458 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1462 /* Return list of recent smtp commands */
1467 gstring * list = NULL;
1470 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1471 if (smtp_connection_had[i] != SCH_NONE)
1472 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1474 for (int i = 0; i < smtp_ch_index; i++)
1475 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1477 s = string_from_gstring(list);
1478 return s ? s : US"";
1484 /*************************************************
1485 * Check HELO line and set sender_helo_name *
1486 *************************************************/
1488 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1489 the domain name of the sending host, or an ip literal in square brackets. The
1490 argument is placed in sender_helo_name, which is in malloc store, because it
1491 must persist over multiple incoming messages. If helo_accept_junk is set, this
1492 host is permitted to send any old junk (needed for some broken hosts).
1493 Otherwise, helo_allow_chars can be used for rogue characters in general
1494 (typically people want to let in underscores).
1497 s the data portion of the line (already past any white space)
1499 Returns: TRUE or FALSE
1503 check_helo(uschar *s)
1506 uschar *end = s + Ustrlen(s);
1507 BOOL yield = fl.helo_accept_junk;
1509 /* Discard any previous helo name */
1511 sender_helo_name = NULL;
1513 /* Skip tests if junk is permitted. */
1517 /* Allow the new standard form for IPv6 address literals, namely,
1518 [IPv6:....], and because someone is bound to use it, allow an equivalent
1519 IPv4 form. Allow plain addresses as well. */
1526 if (strncmpic(s, US"[IPv6:", 6) == 0)
1527 yield = (string_is_ip_address(s+6, NULL) == 6);
1528 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1529 yield = (string_is_ip_address(s+6, NULL) == 4);
1531 yield = (string_is_ip_address(s+1, NULL) != 0);
1536 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1537 that have been configured (usually underscore - sigh). */
1540 for (yield = TRUE; *s; s++)
1541 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1542 Ustrchr(helo_allow_chars, *s) == NULL)
1548 /* Save argument if OK */
1550 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
1558 /*************************************************
1559 * Extract SMTP command option *
1560 *************************************************/
1562 /* This function picks the next option setting off the end of smtp_cmd_data. It
1563 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1564 things that can appear there.
1567 name point this at the name
1568 value point this at the data string
1570 Returns: TRUE if found an option
1574 extract_option(uschar **name, uschar **value)
1578 if (Ustrlen(smtp_cmd_data) <= 0) return FALSE;
1579 v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1580 while (v > smtp_cmd_data && isspace(*v)) v--;
1583 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1585 /* Take care to not stop at a space embedded in a quoted local-part */
1588 do v--; while (v > smtp_cmd_data && *v != '"');
1589 if (v <= smtp_cmd_data) return FALSE;
1593 if (v <= smtp_cmd_data) return FALSE;
1598 while (n > smtp_cmd_data && isalpha(n[-1])) n--;
1599 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1600 if (n <= smtp_cmd_data || !isspace(n[-1])) return FALSE;
1617 /*************************************************
1618 * Reset for new message *
1619 *************************************************/
1621 /* This function is called whenever the SMTP session is reset from
1622 within either of the setup functions; also from the daemon loop.
1624 Argument: the stacking pool storage reset point
1629 smtp_reset(void *reset_point)
1631 recipients_list = NULL;
1632 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1633 raw_recipients_count = recipients_count = recipients_list_max = 0;
1634 message_linecount = 0;
1636 message_body = message_body_end = NULL;
1637 acl_added_headers = NULL;
1638 acl_removed_headers = NULL;
1639 f.queue_only_policy = FALSE;
1640 rcpt_smtp_response = NULL;
1641 fl.rcpt_smtp_response_same = TRUE;
1642 fl.rcpt_in_progress = FALSE;
1643 f.deliver_freeze = FALSE; /* Can be set by ACL */
1644 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1645 fake_response = OK; /* Can be set by ACL */
1646 #ifdef WITH_CONTENT_SCAN
1647 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
1649 f.submission_mode = FALSE; /* Can be set by ACL */
1650 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
1651 f.active_local_from_check = local_from_check; /* Can be set by ACL */
1652 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1653 sending_ip_address = NULL;
1654 return_path = sender_address = NULL;
1655 deliver_localpart_data = deliver_domain_data =
1656 recipient_data = sender_data = NULL; /* Can be set by ACL */
1657 recipient_verify_failure = NULL;
1658 deliver_localpart_parent = deliver_localpart_orig = NULL;
1659 deliver_domain_parent = deliver_domain_orig = NULL;
1660 callout_address = NULL;
1661 submission_name = NULL; /* Can be set by ACL */
1662 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1663 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1664 sender_verified_list = NULL; /* No senders verified */
1665 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1666 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1668 authenticated_sender = NULL;
1669 #ifdef EXPERIMENTAL_BRIGHTMAIL
1671 bmi_verdicts = NULL;
1673 dnslist_domain = dnslist_matched = NULL;
1675 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
1676 spf_result_guessed = FALSE;
1678 #ifndef DISABLE_DKIM
1679 dkim_cur_signer = dkim_signers =
1680 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
1681 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
1682 f.dkim_disable_verify = FALSE;
1683 dkim_collect_input = 0;
1684 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
1685 dkim_key_length = 0;
1687 #ifdef SUPPORT_DMARC
1688 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
1689 dmarc_domain_policy = dmarc_status = dmarc_status_text =
1690 dmarc_used_domain = NULL;
1692 #ifdef EXPERIMENTAL_ARC
1693 arc_state = arc_state_reason = NULL;
1694 arc_received_instance = 0;
1698 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
1699 #ifndef DISABLE_PRDR
1700 prdr_requested = FALSE;
1703 message_smtputf8 = FALSE;
1705 #ifdef WITH_CONTENT_SCAN
1708 body_linecount = body_zerocount = 0;
1710 lookup_value = NULL; /* Can be set by ACL */
1711 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1712 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1713 /* Note that ratelimiters_conn persists across resets. */
1715 /* Reset message ACL variables */
1719 /* Warning log messages are saved in malloc store. They are saved to avoid
1720 repetition in the same message, but it seems right to repeat them for different
1723 while (acl_warn_logged)
1725 string_item *this = acl_warn_logged;
1726 acl_warn_logged = acl_warn_logged->next;
1731 store_reset(reset_point);
1734 return store_mark();
1741 /*************************************************
1742 * Initialize for incoming batched SMTP message *
1743 *************************************************/
1745 /* This function is called from smtp_setup_msg() in the case when
1746 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1747 of messages in one file with SMTP commands between them. All errors must be
1748 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1749 relevant. After an error on a sender, or an invalid recipient, the remainder
1750 of the message is skipped. The value of received_protocol is already set.
1753 Returns: > 0 message successfully started (reached DATA)
1754 = 0 QUIT read or end of file reached
1755 < 0 should not occur
1759 smtp_setup_batch_msg(void)
1762 rmark reset_point = store_mark();
1764 /* Save the line count at the start of each transaction - single commands
1765 like HELO and RSET count as whole transactions. */
1767 bsmtp_transaction_linecount = receive_linecount;
1769 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1771 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
1772 reset_point = smtp_reset(reset_point); /* Reset for start of message */
1774 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1775 value. The values are 2 larger than the required yield of the function. */
1780 uschar *recipient = NULL;
1781 int start, end, sender_domain, recipient_domain;
1783 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1785 /* The HELO/EHLO commands set sender_address_helo if they have
1786 valid data; otherwise they are ignored, except that they do
1787 a reset of the state. */
1792 check_helo(smtp_cmd_data);
1796 cancel_cutthrough_connection(TRUE, US"RSET received");
1797 reset_point = smtp_reset(reset_point);
1798 bsmtp_transaction_linecount = receive_linecount;
1801 /* The MAIL FROM command requires an address as an operand. All we
1802 do here is to parse it for syntactic correctness. The form "<>" is
1803 a special case which converts into an empty string. The start/end
1804 pointers in the original are not used further for this address, as
1805 it is the canonical extracted address which is all that is kept. */
1808 smtp_mailcmd_count++; /* Count for no-mail log */
1810 /* The function moan_smtp_batch() does not return. */
1811 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1813 if (smtp_cmd_data[0] == 0)
1814 /* The function moan_smtp_batch() does not return. */
1815 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1817 /* Reset to start of message */
1819 cancel_cutthrough_connection(TRUE, US"MAIL received");
1820 reset_point = smtp_reset(reset_point);
1822 /* Apply SMTP rewrite */
1824 raw_sender = rewrite_existflags & rewrite_smtp
1825 /* deconst ok as smtp_cmd_data was not const */
1826 ? US rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL,
1827 FALSE, US"", global_rewrite_rules)
1830 /* Extract the address; the TRUE flag allows <> as valid */
1833 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1837 /* The function moan_smtp_batch() does not return. */
1838 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1840 sender_address = string_copy(raw_sender);
1842 /* Qualify unqualified sender addresses if permitted to do so. */
1845 && sender_address[0] != 0 && sender_address[0] != '@')
1846 if (f.allow_unqualified_sender)
1848 /* deconst ok as sender_address was not const */
1849 sender_address = US rewrite_address_qualify(sender_address, FALSE);
1850 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1851 "and rewritten\n", raw_sender);
1853 /* The function moan_smtp_batch() does not return. */
1855 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1860 /* The RCPT TO command requires an address as an operand. All we do
1861 here is to parse it for syntactic correctness. There may be any number
1862 of RCPT TO commands, specifying multiple senders. We build them all into
1863 a data structure that is in argc/argv format. The start/end values
1864 given by parse_extract_address are not used, as we keep only the
1865 extracted address. */
1868 if (!sender_address)
1869 /* The function moan_smtp_batch() does not return. */
1870 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1872 if (smtp_cmd_data[0] == 0)
1873 /* The function moan_smtp_batch() does not return. */
1874 moan_smtp_batch(smtp_cmd_buffer,
1875 "501 RCPT TO must have an address operand");
1877 /* Check maximum number allowed */
1879 if ( recipients_max_expanded > 0
1880 && recipients_count + 1 > recipients_max_expanded)
1881 /* The function moan_smtp_batch() does not return. */
1882 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1883 recipients_max_reject ? "552": "452");
1885 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1886 recipient address */
1888 recipient = rewrite_existflags & rewrite_smtp
1889 /* deconst ok as smtp_cmd_data was not const */
1890 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1891 global_rewrite_rules)
1894 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1895 &recipient_domain, FALSE);
1898 /* The function moan_smtp_batch() does not return. */
1899 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1901 /* If the recipient address is unqualified, qualify it if permitted. Then
1902 add it to the list of recipients. */
1904 if (!recipient_domain)
1905 if (f.allow_unqualified_recipient)
1907 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1909 /* deconst ok as recipient was not const */
1910 recipient = US rewrite_address_qualify(recipient, TRUE);
1912 /* The function moan_smtp_batch() does not return. */
1914 moan_smtp_batch(smtp_cmd_buffer,
1915 "501 recipient address must contain a domain");
1917 receive_add_recipient(recipient, -1);
1921 /* The DATA command is legal only if it follows successful MAIL FROM
1922 and RCPT TO commands. This function is complete when a valid DATA
1923 command is encountered. */
1926 if (!sender_address || recipients_count <= 0)
1927 /* The function moan_smtp_batch() does not return. */
1928 if (!sender_address)
1929 moan_smtp_batch(smtp_cmd_buffer,
1930 "503 MAIL FROM:<sender> command must precede DATA");
1932 moan_smtp_batch(smtp_cmd_buffer,
1933 "503 RCPT TO:<recipient> must precede DATA");
1936 done = 3; /* DATA successfully achieved */
1937 message_ended = END_NOTENDED; /* Indicate in middle of message */
1942 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1949 bsmtp_transaction_linecount = receive_linecount;
1954 f.smtp_in_quit = TRUE;
1961 /* The function moan_smtp_batch() does not return. */
1962 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1967 /* The function moan_smtp_batch() does not return. */
1968 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1973 /* The function moan_smtp_batch() does not return. */
1974 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1979 return done - 2; /* Convert yield values */
1987 smtp_log_tls_fail(const uschar * errstr)
1989 const uschar * conn_info = smtp_get_connection_info();
1991 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
1992 /* I'd like to get separated H= here, but too hard for now */
1994 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2008 socklen_t len = sizeof(is_fastopen);
2010 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2011 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2013 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2018 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2019 f.tcp_in_fastopen = TRUE;
2022 else DEBUG(D_receive)
2023 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2025 # elif defined(TCP_INFO)
2026 struct tcp_info tinfo;
2027 socklen_t len = sizeof(tinfo);
2029 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2030 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2031 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2034 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2035 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2039 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2042 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2043 f.tcp_in_fastopen = TRUE;
2045 else DEBUG(D_receive)
2046 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2053 log_connect_tls_drop(const uschar * what, const uschar * log_msg)
2055 if (log_reject_target)
2057 gstring * g = s_tlslog(NULL);
2058 uschar * tls = string_from_gstring(g);
2060 log_write(L_connection_reject,
2061 log_reject_target, "%s%s%s dropped by %s%s%s",
2062 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
2063 host_and_ident(TRUE),
2066 log_msg ? US": " : US"", log_msg);
2071 /*************************************************
2072 * Start an SMTP session *
2073 *************************************************/
2075 /* This function is called at the start of an SMTP session. Thereafter,
2076 smtp_setup_msg() is called to initiate each separate message. This
2077 function does host-specific testing, and outputs the banner line.
2080 Returns: FALSE if the session can not continue; something has
2081 gone wrong, or the connection to the host is blocked
2085 smtp_start_session(void)
2088 uschar *user_msg, *log_msg;
2093 gettimeofday(&smtp_connection_start, NULL);
2094 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2095 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2098 /* Default values for certain variables */
2100 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2101 smtp_mailcmd_count = 0;
2102 count_nonmail = TRUE_UNSET;
2103 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2104 smtp_delay_mail = smtp_rlm_base;
2105 fl.auth_advertised = FALSE;
2106 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2107 f.pipelining_enable = TRUE;
2108 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2109 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2111 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2112 authentication settings from -oMaa to remain in force. */
2114 if (!host_checking && !f.sender_host_notsocket)
2115 sender_host_auth_pubname = sender_host_authenticated = NULL;
2116 authenticated_by = NULL;
2119 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2120 tls_in.ourcert = tls_in.peercert = NULL;
2122 tls_in.ocsp = OCSP_NOT_REQ;
2123 fl.tls_advertised = FALSE;
2125 fl.dsn_advertised = FALSE;
2127 fl.smtputf8_advertised = FALSE;
2130 /* Reset ACL connection variables */
2134 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2136 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, GET_TAINTED);
2138 smtp_cmd_buffer[0] = 0;
2139 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2141 /* For batched input, the protocol setting can be overridden from the
2142 command line by a trusted caller. */
2144 if (smtp_batched_input)
2146 if (!received_protocol) received_protocol = US"local-bsmtp";
2149 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2150 reset later if any of EHLO/AUTH/STARTTLS are received. */
2154 (sender_host_address ? protocols : protocols_local) [pnormal];
2156 /* Set up the buffer for inputting using direct read() calls, and arrange to
2157 call the local functions instead of the standard C ones. */
2161 receive_getc = smtp_getc;
2162 receive_getbuf = smtp_getbuf;
2163 receive_get_cache = smtp_get_cache;
2164 receive_hasc = smtp_hasc;
2165 receive_ungetc = smtp_ungetc;
2166 receive_feof = smtp_feof;
2167 receive_ferror = smtp_ferror;
2168 lwr_receive_getc = NULL;
2169 lwr_receive_getbuf = NULL;
2170 lwr_receive_hasc = NULL;
2171 lwr_receive_ungetc = NULL;
2173 /* Set up the message size limit; this may be host-specific */
2175 GET_OPTION("message_size_limit");
2176 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2177 if (expand_string_message)
2179 if (thismessage_size_limit == -1)
2180 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2181 "%s", expand_string_message);
2183 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2184 "%s", expand_string_message);
2185 smtp_closedown(US"Temporary local problem - please try later");
2189 /* When a message is input locally via the -bs or -bS options, sender_host_
2190 unknown is set unless -oMa was used to force an IP address, in which case it
2191 is checked like a real remote connection. When -bs is used from inetd, this
2192 flag is not set, causing the sending host to be checked. The code that deals
2193 with IP source routing (if configured) is never required for -bs or -bS and
2194 the flag sender_host_notsocket is used to suppress it.
2196 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2197 reserve for certain hosts and/or networks. */
2199 if (!f.sender_host_unknown)
2202 BOOL reserved_host = FALSE;
2204 /* Look up IP options (source routing info) on the socket if this is not an
2205 -oMa "host", and if any are found, log them and drop the connection.
2207 Linux (and others now, see below) is different to everyone else, so there
2208 has to be some conditional compilation here. Versions of Linux before 2.1.15
2209 used a structure whose name was "options". Somebody finally realized that
2210 this name was silly, and it got changed to "ip_options". I use the
2211 newer name here, but there is a fudge in the script that sets up os.h
2212 to define a macro in older Linux systems.
2214 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2215 glibc 2, which has chosen ip_opts for the structure name. This is now
2216 really a glibc thing rather than a Linux thing, so the condition name
2217 has been changed to reflect this. It is relevant also to GNU/Hurd.
2219 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2220 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2221 a special macro defined in the os.h file.
2223 Some DGUX versions on older hardware appear not to support IP options at
2224 all, so there is now a general macro which can be set to cut out this
2227 How to do this properly in IPv6 is not yet known. */
2229 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2231 # ifdef GLIBC_IP_OPTIONS
2232 # if (!defined __GLIBC__) || (__GLIBC__ < 2)
2237 # elif defined DARWIN_IP_OPTIONS
2243 if (!host_checking && !f.sender_host_notsocket)
2246 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2247 struct ip_options *ipopt = store_get(optlen, GET_UNTAINTED);
2248 # elif OPTSTYLE == 2
2249 struct ip_opts ipoptblock;
2250 struct ip_opts *ipopt = &ipoptblock;
2251 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2253 struct ipoption ipoptblock;
2254 struct ipoption *ipopt = &ipoptblock;
2255 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2258 /* Occasional genuine failures of getsockopt() have been seen - for
2259 example, "reset by peer". Therefore, just log and give up on this
2260 call, unless the error is ENOPROTOOPT. This error is given by systems
2261 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2262 of writing. So for that error, carry on - we just can't do an IP options
2265 DEBUG(D_receive) debug_printf("checking for IP options\n");
2267 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2270 if (errno != ENOPROTOOPT)
2272 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2273 host_and_ident(FALSE), strerror(errno));
2274 smtp_printf("451 SMTP service not available\r\n", SP_NO_MORE);
2279 /* Deal with any IP options that are set. On the systems I have looked at,
2280 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2281 more logging data than will fit in big_buffer. Nevertheless, after somebody
2282 questioned this code, I've added in some paranoid checking. */
2284 else if (optlen > 0)
2286 uschar * p = big_buffer;
2287 uschar * pend = big_buffer + big_buffer_size;
2290 struct in_addr addr;
2293 uschar * optstart = US (ipopt->__data);
2294 # elif OPTSTYLE == 2
2295 uschar * optstart = US (ipopt->ip_opts);
2297 uschar * optstart = US (ipopt->ipopt_list);
2300 DEBUG(D_receive) debug_printf("IP options exist\n");
2302 Ustrcpy(p, "IP options on incoming call:");
2305 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2320 string_format(p, pend-p, " %s [@%s",
2321 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2322 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr)))))
2323 # elif OPTSTYLE == 2
2324 string_format(p, pend-p, " %s [@%s",
2325 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2326 inet_ntoa(ipopt->ip_dst))
2328 string_format(p, pend-p, " %s [@%s",
2329 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2330 inet_ntoa(ipopt->ipopt_dst))
2339 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2341 while (optcount-- > 0)
2343 memcpy(&addr, adptr, sizeof(addr));
2344 if (!string_format(p, pend - p - 1, "%s%s",
2345 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2351 adptr += sizeof(struct in_addr);
2359 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2362 for (int i = 0; i < opt[1]; i++)
2363 p += sprintf(CS p, "%2.2x ", opt[i]);
2371 log_write(0, LOG_MAIN, "%s", big_buffer);
2373 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2375 log_write(0, LOG_MAIN|LOG_REJECT,
2376 "connection from %s refused (IP options)", host_and_ident(FALSE));
2378 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2382 /* Length of options = 0 => there are no options */
2384 else DEBUG(D_receive) debug_printf("no IP options found\n");
2386 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2388 /* Set keep-alive in socket options. The option is on by default. This
2389 setting is an attempt to get rid of some hanging connections that stick in
2390 read() when the remote end (usually a dialup) goes away. */
2392 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2393 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2395 /* If the current host matches host_lookup, set the name by doing a
2396 reverse lookup. On failure, sender_host_name will be NULL and
2397 host_lookup_failed will be TRUE. This may or may not be serious - optional
2400 if (verify_check_host(&host_lookup) == OK)
2402 (void)host_name_lookup();
2403 host_build_sender_fullhost();
2406 /* Delay this until we have the full name, if it is looked up. */
2408 set_process_info("handling incoming connection from %s",
2409 host_and_ident(FALSE));
2411 /* Expand smtp_receive_timeout, if needed */
2413 if (smtp_receive_timeout_s)
2416 if ( !(exp = expand_string(smtp_receive_timeout_s))
2418 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2420 log_write(0, LOG_MAIN|LOG_PANIC,
2421 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2424 /* Test for explicit connection rejection */
2426 if (verify_check_host(&host_reject_connection) == OK)
2428 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2429 "from %s (host_reject_connection)", host_and_ident(FALSE));
2431 if (!tls_in.on_connect)
2433 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2437 /* Test with TCP Wrappers if so configured. There is a problem in that
2438 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2439 such as disks dying. In these cases, it is desirable to reject with a 4xx
2440 error instead of a 5xx error. There isn't a "right" way to detect such
2441 problems. The following kludge is used: errno is zeroed before calling
2442 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2443 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2446 #ifdef USE_TCP_WRAPPERS
2448 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2449 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2450 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2451 expand_string_message);
2453 if (!hosts_ctl(tcp_wrappers_name,
2454 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2455 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2456 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2458 if (errno == 0 || errno == ENOENT)
2460 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2461 log_write(L_connection_reject,
2462 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2463 "(tcp wrappers)", host_and_ident(FALSE));
2464 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2468 int save_errno = errno;
2469 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2470 "errno value %d\n", save_errno);
2471 log_write(L_connection_reject,
2472 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2473 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2474 smtp_printf("451 Temporary local problem - please try later\r\n", SP_NO_MORE);
2480 /* Check for reserved slots. The value of smtp_accept_count has already been
2481 incremented to include this process. */
2483 if (smtp_accept_max > 0 &&
2484 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2486 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2488 log_write(L_connection_reject,
2489 LOG_MAIN, "temporarily refused connection from %s: not in "
2490 "reserve list: connected=%d max=%d reserve=%d%s",
2491 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2492 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2493 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2494 "please try again later\r\n", SP_NO_MORE, smtp_active_hostname);
2497 reserved_host = TRUE;
2500 /* If a load level above which only messages from reserved hosts are
2501 accepted is set, check the load. For incoming calls via the daemon, the
2502 check is done in the superior process if there are no reserved hosts, to
2503 save a fork. In all cases, the load average will already be available
2504 in a global variable at this point. */
2506 if (smtp_load_reserve >= 0 &&
2507 load_average > smtp_load_reserve &&
2509 verify_check_host(&smtp_reserve_hosts) != OK)
2511 log_write(L_connection_reject,
2512 LOG_MAIN, "temporarily refused connection from %s: not in "
2513 "reserve list and load average = %.2f", host_and_ident(FALSE),
2514 (double)load_average/1000.0);
2515 smtp_printf("421 %s: Too much load; please try again later\r\n", SP_NO_MORE,
2516 smtp_active_hostname);
2520 /* Determine whether unqualified senders or recipients are permitted
2521 for this host. Unfortunately, we have to do this every time, in order to
2522 set the flags so that they can be inspected when considering qualifying
2523 addresses in the headers. For a site that permits no qualification, this
2524 won't take long, however. */
2526 f.allow_unqualified_sender =
2527 verify_check_host(&sender_unqualified_hosts) == OK;
2529 f.allow_unqualified_recipient =
2530 verify_check_host(&recipient_unqualified_hosts) == OK;
2532 /* Determine whether HELO/EHLO is required for this host. The requirement
2533 can be hard or soft. */
2535 fl.helo_verify_required = verify_check_host(&helo_verify_hosts) == OK;
2536 if (!fl.helo_verify_required)
2537 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2539 /* Determine whether this hosts is permitted to send syntactic junk
2540 after a HELO or EHLO command. */
2542 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2545 /* Expand recipients_max, if needed */
2547 uschar * rme = expand_string(recipients_max);
2548 recipients_max_expanded = atoi(CCS rme);
2550 /* For batch SMTP input we are now done. */
2552 if (smtp_batched_input) return TRUE;
2554 #if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS) || defined(EXPERIMETAL_XCLIENT)
2555 proxy_session = FALSE;
2558 #ifdef SUPPORT_PROXY
2559 /* If valid Proxy Protocol source is connecting, set up session.
2560 Failure will not allow any SMTP function other than QUIT. */
2562 f.proxy_session_failed = FALSE;
2563 if (proxy_protocol_host())
2565 os_non_restarting_signal(SIGALRM, command_timeout_handler);
2566 proxy_protocol_setup();
2570 /* Run the connect ACL if it exists */
2573 GET_OPTION("acl_smtp_connect");
2574 if (acl_smtp_connect)
2577 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2581 if (tls_in.on_connect)
2582 log_connect_tls_drop(US"'connect' ACL", log_msg);
2585 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2590 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2591 smtps port for use with older style SSL MTAs. */
2594 if (tls_in.on_connect)
2596 if (tls_server_start(&user_msg) != OK)
2597 return smtp_log_tls_fail(user_msg);
2598 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
2602 /* Output the initial message for a two-way SMTP connection. It may contain
2603 newlines, which then cause a multi-line response to be given. */
2605 code = US"220"; /* Default status code */
2606 esc = US""; /* Default extended status code */
2607 esclen = 0; /* Length of esc */
2613 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2617 esclen = codelen - 4;
2622 GET_OPTION("smtp_banner");
2623 if (!(s = expand_string(smtp_banner)))
2625 log_write(0, f.expand_string_forcedfail ? LOG_MAIN : LOG_MAIN|LOG_PANIC_DIE,
2626 "Expansion of \"%s\" (smtp_banner) failed: %s",
2627 smtp_banner, expand_string_message);
2628 /* for force-fail */
2630 if (tls_in.on_connect) tls_close(NULL, TLS_SHUTDOWN_WAIT);
2636 /* Remove any terminating newlines; might as well remove trailing space too */
2639 while (p > s && isspace(p[-1])) p--;
2640 s = string_copyn(s, p-s);
2642 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2643 is all contained in a single IP packet. The original code wrote out the
2644 greeting using several calls to fprint/fputc, and on busy servers this could
2645 cause it to be split over more than one packet - which caused CC:Mail to fall
2646 over when it got the second part of the greeting after sending its first
2647 command. Sigh. To try to avoid this, build the complete greeting message
2648 first, and output it in one fell swoop. This gives a better chance of it
2649 ending up as a single packet. */
2651 ss = string_get(256);
2654 do /* At least once, in case we have an empty string */
2657 uschar *linebreak = Ustrchr(p, '\n');
2658 ss = string_catn(ss, code, 3);
2662 ss = string_catn(ss, US" ", 1);
2666 len = linebreak - p;
2667 ss = string_catn(ss, US"-", 1);
2669 ss = string_catn(ss, esc, esclen);
2670 ss = string_catn(ss, p, len);
2671 ss = string_catn(ss, US"\r\n", 2);
2677 /* Before we write the banner, check that there is no input pending, unless
2678 this synchronisation check is disabled. */
2680 #ifndef DISABLE_PIPE_CONNECT
2681 fl.pipe_connect_acceptable =
2682 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
2685 if (fl.pipe_connect_acceptable)
2686 f.smtp_in_early_pipe_used = TRUE;
2692 unsigned n = smtp_inend - smtp_inptr;
2693 if (n > 128) n = 128;
2695 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2696 "synchronization error (input sent without waiting for greeting): "
2697 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2698 string_printing(string_copyn(smtp_inptr, n)));
2699 smtp_printf("554 SMTP synchronization error\r\n", SP_NO_MORE);
2703 /* Now output the banner */
2704 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
2707 #ifndef DISABLE_PIPE_CONNECT
2708 fl.pipe_connect_acceptable && pipeline_connect_sends(),
2714 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2715 handshake arrived. If so we must have managed a TFO. */
2718 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
2728 /*************************************************
2729 * Handle SMTP syntax and protocol errors *
2730 *************************************************/
2732 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2733 to do so. Then transmit the error response. The return value depends on the
2734 number of syntax and protocol errors in this SMTP session.
2737 type error type, given as a log flag bit
2738 code response code; <= 0 means don't send a response
2739 data data to reflect in the response (can be NULL)
2740 errmess the error message
2742 Returns: -1 limit of syntax/protocol errors NOT exceeded
2743 +1 limit of syntax/protocol errors IS exceeded
2745 These values fit in with the values of the "done" variable in the main
2746 processing loop in smtp_setup_msg(). */
2749 synprot_error(int type, int code, uschar *data, uschar *errmess)
2753 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2754 type == L_smtp_syntax_error ? "syntax" : "protocol",
2755 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2757 if (++synprot_error_count > smtp_max_synprot_errors)
2760 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2761 "syntax or protocol errors (last command was \"%s\", %Y)",
2762 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
2769 smtp_printf("%d%c%s%s%s\r\n", SP_NO_MORE, code, yield == 1 ? '-' : ' ',
2770 data ? data : US"", data ? US": " : US"", errmess);
2772 smtp_printf("%d Too many syntax or protocol errors\r\n", SP_NO_MORE, code);
2781 /*************************************************
2782 * Send SMTP response, possibly multiline *
2783 *************************************************/
2785 /* There are, it seems, broken clients out there that cannot handle multiline
2786 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2787 output nothing for non-final calls, and only the first line for anything else.
2790 code SMTP code, may involve extended status codes
2791 codelen length of smtp code; if > 4 there's an ESC
2792 final FALSE if the last line isn't the final line
2793 msg message text, possibly containing newlines
2799 smtp_respond(uschar * code, int codelen, BOOL final, uschar * msg)
2804 if (!final && f.no_multiline_responses) return;
2809 esclen = codelen - 4;
2812 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2813 have had the same. Note: this code is also present in smtp_printf(). It would
2814 be tidier to have it only in one place, but when it was added, it was easier to
2815 do it that way, so as not to have to mess with the code for the RCPT command,
2816 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2818 if (fl.rcpt_in_progress)
2820 if (!rcpt_smtp_response)
2821 rcpt_smtp_response = string_copy(msg);
2822 else if (fl.rcpt_smtp_response_same &&
2823 Ustrcmp(rcpt_smtp_response, msg) != 0)
2824 fl.rcpt_smtp_response_same = FALSE;
2825 fl.rcpt_in_progress = FALSE;
2828 /* Now output the message, splitting it up into multiple lines if necessary.
2829 We only handle pipelining these responses as far as nonfinal/final groups,
2830 not the whole MAIL/RCPT/DATA response set. */
2834 uschar *nl = Ustrchr(msg, '\n');
2837 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
2840 else if (nl[1] == 0 || f.no_multiline_responses)
2842 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
2843 (int)(nl - msg), msg);
2848 smtp_printf("%.3s-%.*s%.*s\r\n", SP_MORE, code, esclen, esc, (int)(nl - msg), msg);
2850 Uskip_whitespace(&msg);
2858 /*************************************************
2859 * Parse user SMTP message *
2860 *************************************************/
2862 /* This function allows for user messages overriding the response code details
2863 by providing a suitable response code string at the start of the message
2864 user_msg. Check the message for starting with a response code and optionally an
2865 extended status code. If found, check that the first digit is valid, and if so,
2866 change the code pointer and length to use the replacement. An invalid code
2867 causes a panic log; in this case, if the log messages is the same as the user
2868 message, we must also adjust the value of the log message to show the code that
2869 is actually going to be used (the original one).
2871 This function is global because it is called from receive.c as well as within
2874 Note that the code length returned includes the terminating whitespace
2875 character, which is always included in the regex match.
2878 code SMTP code, may involve extended status codes
2879 codelen length of smtp code; if > 4 there's an ESC
2881 log_msg optional log message, to be adjusted with the new SMTP code
2882 check_valid if true, verify the response code
2888 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2894 if (!msg || !*msg || !regex_match(regex_smtp_code, *msg, -1, &match))
2897 len = Ustrlen(match);
2898 if (check_valid && (*msg)[0] != (*code)[0])
2900 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2901 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2902 if (log_msg && *log_msg == *msg)
2903 *log_msg = string_sprintf("%s %s", *code, *log_msg + len);
2908 *codelen = len; /* Includes final space */
2910 *msg += len; /* Chop the code off the message */
2917 /*************************************************
2918 * Handle an ACL failure *
2919 *************************************************/
2921 /* This function is called when acl_check() fails. As well as calls from within
2922 this module, it is called from receive.c for an ACL after DATA. It sorts out
2923 logging the incident, and sends the error response. A message containing
2924 newlines is turned into a multiline SMTP response, but for logging, only the
2927 There's a table of default permanent failure response codes to use in
2928 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2929 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2930 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2931 state, because there are broken clients that try VRFY before RCPT. A 5xx
2932 response should be given only when the address is positively known to be
2933 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2934 no explicit code, but if there is one we let it know best.
2935 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2937 From Exim 4.63, it is possible to override the response code details by
2938 providing a suitable response code string at the start of the message provided
2939 in user_msg. The code's first digit is checked for validity.
2942 where where the ACL was called from
2944 user_msg a message that can be included in an SMTP response
2945 log_msg a message for logging
2947 Returns: 0 in most cases
2948 2 if the failure code was FAIL_DROP, in which case the
2949 SMTP connection should be dropped (this value fits with the
2950 "done" variable in smtp_setup_msg() below)
2954 smtp_handle_acl_fail(int where, int rc, uschar * user_msg, uschar * log_msg)
2956 BOOL drop = rc == FAIL_DROP;
2960 uschar *sender_info = US"";
2963 if (drop) rc = FAIL;
2965 /* Set the default SMTP code, and allow a user message to change it. */
2967 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2968 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2969 where != ACL_WHERE_VRFY);
2971 /* We used to have sender_address here; however, there was a bug that was not
2972 updating sender_address after a rewrite during a verify. When this bug was
2973 fixed, sender_address at this point became the rewritten address. I'm not sure
2974 this is what should be logged, so I've changed to logging the unrewritten
2975 address to retain backward compatibility. */
2979 #ifdef WITH_CONTENT_SCAN
2980 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
2982 case ACL_WHERE_PREDATA: what = US"DATA"; break;
2983 case ACL_WHERE_DATA: what = US"after DATA"; break;
2984 #ifndef DISABLE_PRDR
2985 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
2989 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
2992 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
2995 for (s = smtp_cmd_data; *s && !isspace(*s); ) s++;
2996 lim = s - smtp_cmd_data; /* atop after method */
2998 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
3003 case ACL_WHERE_RCPT:
3004 case ACL_WHERE_DATA:
3005 #ifdef WITH_CONTENT_SCAN
3006 case ACL_WHERE_MIME:
3008 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3009 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3010 sender_host_authenticated ? US" A=" : US"",
3011 sender_host_authenticated ? sender_host_authenticated : US"",
3012 sender_host_authenticated && authenticated_id ? US":" : US"",
3013 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3018 /* If there's been a sender verification failure with a specific message, and
3019 we have not sent a response about it yet, do so now, as a preliminary line for
3020 failures, but not defers. However, always log it for defer, and log it for fail
3021 unless the sender_verify_fail log selector has been turned off. */
3023 if (sender_verified_failed &&
3024 !testflag(sender_verified_failed, af_sverify_told))
3026 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3027 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3029 setflag(sender_verified_failed, af_sverify_told);
3031 if (rc != FAIL || LOGGING(sender_verify_fail))
3032 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3033 host_and_ident(TRUE),
3034 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3035 sender_verified_failed->address,
3036 (sender_verified_failed->message == NULL)? US"" :
3037 string_sprintf(": %s", sender_verified_failed->message));
3039 if (rc == FAIL && sender_verified_failed->user_message)
3040 smtp_respond(smtp_code, codelen, SR_NOT_FINAL, string_sprintf(
3041 testflag(sender_verified_failed, af_verify_pmfail)?
3042 "Postmaster verification failed while checking <%s>\n%s\n"
3043 "Several RFCs state that you are required to have a postmaster\n"
3044 "mailbox for each mail domain. This host does not accept mail\n"
3045 "from domains whose servers reject the postmaster address."
3047 testflag(sender_verified_failed, af_verify_nsfail)?
3048 "Callback setup failed while verifying <%s>\n%s\n"
3049 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3050 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3051 "RFC requirements, and stops you from receiving standard bounce\n"
3052 "messages. This host does not accept mail from domains whose servers\n"
3055 "Verification failed for <%s>\n%s",
3056 sender_verified_failed->address,
3057 sender_verified_failed->user_message));
3059 fl.rcpt_in_progress = save_rcpt_in_progress;
3062 /* Sort out text for logging */
3064 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3065 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3067 /* Send permanent failure response to the command, but the code used isn't
3068 always a 5xx one - see comments at the start of this function. If the original
3069 rc was FAIL_DROP we drop the connection and yield 2. */
3072 smtp_respond(smtp_code, codelen, SR_FINAL,
3073 user_msg ? user_msg : US"Administrative prohibition");
3075 /* Send temporary failure response to the command. Don't give any details,
3076 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3077 verb, and for a header verify when smtp_return_error_details is set.
3079 This conditional logic is all somewhat of a mess because of the odd
3080 interactions between temp_details and return_error_details. One day it should
3081 be re-implemented in a tidier fashion. */
3084 if (f.acl_temp_details && user_msg)
3086 if ( smtp_return_error_details
3087 && sender_verified_failed
3088 && sender_verified_failed->message
3090 smtp_respond(smtp_code, codelen, SR_NOT_FINAL, sender_verified_failed->message);
3092 smtp_respond(smtp_code, codelen, SR_FINAL, user_msg);
3095 smtp_respond(smtp_code, codelen, SR_FINAL,
3096 US"Temporary local problem - please try later");
3098 /* Log the incident to the logs that are specified by log_reject_target
3099 (default main, reject). This can be empty to suppress logging of rejections. If
3100 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3101 is closing if required and return 2. */
3103 if (log_reject_target)
3106 gstring * g = s_tlslog(NULL);
3107 uschar * tls = string_from_gstring(g);
3108 if (!tls) tls = US"";
3110 uschar * tls = US"";
3112 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3113 log_reject_target, "%s%s%s %s%srejected %s%s",
3114 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3115 host_and_ident(TRUE),
3118 rc == FAIL ? US"" : US"temporarily ",
3122 if (!drop) return 0;
3124 log_close_event(US"by DROP in ACL");
3126 /* Run the not-quit ACL, but without any custom messages. This should not be a
3127 problem, because we get here only if some other ACL has issued "drop", and
3128 in that case, *its* custom messages will have been used above. */
3130 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3132 /* An overenthusiastic fail2ban/iptables implimentation has been seen to result
3133 in the TCP conn staying open, and retrying, despite this process exiting. A
3134 malicious client could possibly do the same, tying up server netowrking
3135 resources. Close the socket explicitly to try to avoid that (there's a note in
3136 the Linux socket(7) manpage, SO_LINGER para, to the effect that exim() without
3137 close() results in the socket always lingering). */
3139 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3140 DEBUG(D_any) debug_printf_indent("SMTP(close)>>\n");
3141 (void) fclose(smtp_in);
3142 (void) fclose(smtp_out);
3150 /*************************************************
3151 * Handle SMTP exit when QUIT is not given *
3152 *************************************************/
3154 /* This function provides a logging/statistics hook for when an SMTP connection
3155 is dropped on the floor or the other end goes away. It's a global function
3156 because it's called from receive.c as well as this module. As well as running
3157 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3158 response, either with a custom message from the ACL, or using a default. There
3159 is one case, however, when no message is output - after "drop". In that case,
3160 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3161 passed to this function.
3163 In case things go wrong while processing this function, causing an error that
3164 may re-enter this function, there is a recursion check.
3167 reason What $smtp_notquit_reason will be set to in the ACL;
3168 if NULL, the ACL is not run
3169 code The error code to return as part of the response
3170 defaultrespond The default message if there's no user_msg
3176 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3179 uschar *user_msg = NULL;
3180 uschar *log_msg = NULL;
3182 /* Check for recursive call */
3184 if (fl.smtp_exit_function_called)
3186 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3190 fl.smtp_exit_function_called = TRUE;
3192 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3194 GET_OPTION("acl_smtp_notquit");
3195 if (acl_smtp_notquit && reason)
3197 smtp_notquit_reason = reason;
3198 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3199 &log_msg)) == ERROR)
3200 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3204 /* If the connection was dropped, we certainly are no longer talking TLS */
3205 tls_in.active.sock = -1;
3207 /* Write an SMTP response if we are expected to give one. As the default
3208 responses are all internal, they should be reasonable size. */
3210 if (code && defaultrespond)
3213 smtp_respond(code, 3, SR_FINAL, user_msg);
3219 va_start(ap, defaultrespond);
3220 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3222 smtp_printf("%s %Y\r\n", SP_NO_MORE, code, g);
3231 /*************************************************
3232 * Verify HELO argument *
3233 *************************************************/
3235 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3236 matched. It is also called from ACL processing if verify = helo is used and
3237 verification was not previously tried (i.e. helo_try_verify_hosts was not
3238 matched). The result of its processing is to set helo_verified and
3239 helo_verify_failed. These variables should both be FALSE for this function to
3242 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3243 for IPv6 ::ffff: literals.
3246 Returns: TRUE if testing was completed;
3247 FALSE on a temporary failure
3251 smtp_verify_helo(void)
3255 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3258 if (sender_helo_name == NULL)
3260 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3263 /* Deal with the case of -bs without an IP address */
3265 else if (sender_host_address == NULL)
3267 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3268 f.helo_verified = TRUE;
3271 /* Deal with the more common case when there is a sending IP address */
3273 else if (sender_helo_name[0] == '[')
3275 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3276 Ustrlen(sender_host_address)) == 0;
3279 if (!f.helo_verified)
3281 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3282 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3283 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3288 { if (f.helo_verified) debug_printf("matched host address\n"); }
3291 /* Do a reverse lookup if one hasn't already given a positive or negative
3292 response. If that fails, or the name doesn't match, try checking with a forward
3297 if (sender_host_name == NULL && !host_lookup_failed)
3298 yield = host_name_lookup() != DEFER;
3300 /* If a host name is known, check it and all its aliases. */
3302 if (sender_host_name)
3303 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3305 sender_helo_dnssec = sender_host_dnssec;
3306 HDEBUG(D_receive) debug_printf("matched host name\n");
3310 uschar **aliases = sender_host_aliases;
3312 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3314 sender_helo_dnssec = sender_host_dnssec;
3318 HDEBUG(D_receive) if (f.helo_verified)
3319 debug_printf("matched alias %s\n", *(--aliases));
3322 /* Final attempt: try a forward lookup of the helo name */
3324 if (!f.helo_verified)
3328 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3330 {.request = US"*", .require = US""};
3332 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3334 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3335 NULL, NULL, NULL, &d, NULL, NULL);
3336 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3337 for (host_item * hh = &h; hh; hh = hh->next)
3338 if (Ustrcmp(hh->address, sender_host_address) == 0)
3340 f.helo_verified = TRUE;
3341 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3343 debug_printf("IP address for %s matches calling address\n"
3344 "Forward DNS security status: %sverified\n",
3345 sender_helo_name, sender_helo_dnssec ? "" : "un");
3351 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3358 /*************************************************
3359 * Send user response message *
3360 *************************************************/
3362 /* This function is passed a default response code and a user message. It calls
3363 smtp_message_code() to check and possibly modify the response code, and then
3364 calls smtp_respond() to transmit the response. I put this into a function
3365 just to avoid a lot of repetition.
3368 code the response code
3369 user_msg the user message
3375 smtp_user_msg(uschar *code, uschar *user_msg)
3378 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3379 smtp_respond(code, len, SR_FINAL, user_msg);
3385 smtp_in_auth(auth_instance *au, uschar ** smtp_resp, uschar ** errmsg)
3387 const uschar *set_id = NULL;
3390 /* Set up globals for error messages */
3392 authenticator_name = au->name;
3393 driver_srcfile = au->srcfile;
3394 driver_srcline = au->srcline;
3396 /* Run the checking code, passing the remainder of the command line as
3397 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3398 it as the only set numerical variable. The authenticator may set $auth<n>
3399 and also set other numeric variables. The $auth<n> variables are preferred
3400 nowadays; the numerical variables remain for backwards compatibility.
3402 Afterwards, have a go at expanding the set_id string, even if
3403 authentication failed - for bad passwords it can be useful to log the
3404 userid. On success, require set_id to expand and exist, and put it in
3405 authenticated_id. Save this in permanent store, as the working store gets
3406 reset at HELO, RSET, etc. */
3408 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3410 expand_nlength[0] = 0; /* $0 contains nothing */
3412 rc = (au->info->servercode)(au, smtp_cmd_data);
3413 if (au->set_id) set_id = expand_string(au->set_id);
3414 expand_nmax = -1; /* Reset numeric variables */
3415 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3416 driver_srcfile = authenticator_name = NULL; driver_srcline = 0;
3418 /* The value of authenticated_id is stored in the spool file and printed in
3419 log lines. It must not contain binary zeros or newline characters. In
3420 normal use, it never will, but when playing around or testing, this error
3421 can (did) happen. To guard against this, ensure that the id contains only
3422 printing characters. */
3424 if (set_id) set_id = string_printing(set_id);
3426 /* For the non-OK cases, set up additional logging data if set_id
3430 set_id = set_id && *set_id
3431 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3433 /* Switch on the result */
3438 if (!au->set_id || set_id) /* Complete success */
3440 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3441 sender_host_authenticated = au->name;
3442 sender_host_auth_pubname = au->public_name;
3443 authentication_failed = FALSE;
3444 authenticated_fail_id = NULL; /* Impossible to already be set? */
3447 (sender_host_address ? protocols : protocols_local)
3448 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3449 *smtp_resp = *errmsg = US"235 Authentication succeeded";
3450 authenticated_by = au;
3454 /* Authentication succeeded, but we failed to expand the set_id string.
3455 Treat this as a temporary error. */
3457 auth_defer_msg = expand_string_message;
3461 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3462 *smtp_resp = string_sprintf("435 Unable to authenticate at present%s",
3463 auth_defer_user_msg);
3464 *errmsg = string_sprintf("435 Unable to authenticate at present%s: %s",
3465 set_id, auth_defer_msg);
3469 *smtp_resp = *errmsg = US"501 Invalid base64 data";
3473 *smtp_resp = *errmsg = US"501 Authentication cancelled";
3477 *smtp_resp = *errmsg = US"553 Initial data not expected";
3481 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3482 *smtp_resp = US"535 Incorrect authentication data";
3483 *errmsg = string_sprintf("535 Incorrect authentication data%s", set_id);
3487 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3488 *smtp_resp = US"435 Internal error";
3489 *errmsg = string_sprintf("435 Internal error%s: return %d from authentication "
3490 "check", set_id, rc);
3502 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3505 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3507 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3509 rd = Ustrlen(recipient) + 1;
3510 /* deconst ok as *recipient was not const */
3511 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3514 smtp_printf("501 %s: recipient address must contain a domain\r\n", SP_NO_MORE,
3516 log_write(L_smtp_syntax_error,
3517 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3518 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3526 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3529 f.smtp_in_quit = TRUE;
3530 incomplete_transaction_log(US"QUIT");
3531 GET_OPTION("acl_smtp_quit");
3533 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3535 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3538 #ifdef EXIM_TCP_CORK
3539 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
3543 smtp_respond(US"221", 3, SR_FINAL, *user_msgp);
3545 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
3547 #ifdef SERVERSIDE_CLOSE_NOWAIT
3548 # ifndef DISABLE_TLS
3549 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3552 log_close_event(US"by QUIT");
3555 # ifndef DISABLE_TLS
3556 tls_close(NULL, TLS_SHUTDOWN_WAIT);
3559 log_close_event(US"by QUIT");
3561 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
3562 The socket should become readble (though with no data) */
3564 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3565 #endif /*!SERVERSIDE_CLOSE_NOWAIT*/
3570 smtp_rset_handler(void)
3573 incomplete_transaction_log(US"RSET");
3574 smtp_printf("250 Reset OK\r\n", SP_NO_MORE);
3575 cmd_list[CL_RSET].is_mail_cmd = FALSE;
3576 if (chunking_state > CHUNKING_OFFERED)
3577 chunking_state = CHUNKING_OFFERED;
3582 expand_mailmax(const uschar * s)
3584 if (!(s = expand_cstring(s)))
3585 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
3586 return *s ? Uatoi(s) : 0;
3589 /*************************************************
3590 * Initialize for SMTP incoming message *
3591 *************************************************/
3593 /* This function conducts the initial dialogue at the start of an incoming SMTP
3594 message, and builds a list of recipients. However, if the incoming message
3595 is part of a batch (-bS option) a separate function is called since it would
3596 be messy having tests splattered about all over this function. This function
3597 therefore handles the case where interaction is occurring. The input and output
3598 files are set up in smtp_in and smtp_out.
3600 The global recipients_list is set to point to a vector of recipient_item
3601 blocks, whose number is given by recipients_count. This is extended by the
3602 receive_add_recipient() function. The global variable sender_address is set to
3603 the sender's address. The yield is +1 if a message has been successfully
3604 started, 0 if a QUIT command was encountered or the connection was refused from
3605 the particular host, or -1 if the connection was lost.
3609 Returns: > 0 message successfully started (reached DATA)
3610 = 0 QUIT read or end of file reached or call refused
3615 smtp_setup_msg(void)
3618 BOOL toomany = FALSE;
3619 BOOL discarded = FALSE;
3620 BOOL last_was_rej_mail = FALSE;
3621 BOOL last_was_rcpt = FALSE;
3622 rmark reset_point = store_mark();
3624 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3626 /* Reset for start of new message. We allow one RSET not to be counted as a
3627 nonmail command, for those MTAs that insist on sending it between every
3628 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3629 TLS between messages (an Exim client may do this if it has messages queued up
3630 for the host). Note: we do NOT reset AUTH at this point. */
3632 reset_point = smtp_reset(reset_point);
3633 message_ended = END_NOTSTARTED;
3635 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3637 cmd_list[CL_RSET].is_mail_cmd = TRUE;
3638 cmd_list[CL_HELO].is_mail_cmd = TRUE;
3639 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
3641 cmd_list[CL_STLS].is_mail_cmd = TRUE;
3644 if (lwr_receive_getc != NULL)
3646 /* This should have already happened, but if we've gotten confused,
3647 force a reset here. */
3648 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
3649 bdat_pop_receive_functions();
3652 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3654 had_command_sigterm = 0;
3655 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3657 /* Batched SMTP is handled in a different function. */
3659 if (smtp_batched_input) return smtp_setup_batch_msg();
3662 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3663 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3664 US &off, sizeof(off));
3667 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3668 value. The values are 2 larger than the required yield of the function. */
3672 const uschar **argv;
3673 uschar *etrn_command;
3674 uschar *etrn_serialize_key;
3676 uschar *log_msg, *smtp_code;
3677 uschar *user_msg = NULL;
3678 uschar *recipient = NULL;
3679 uschar *hello = NULL;
3681 BOOL was_rej_mail = FALSE;
3682 BOOL was_rcpt = FALSE;
3683 void (*oldsignal)(int);
3685 int start, end, sender_domain, recipient_domain;
3688 uschar *orcpt = NULL;
3693 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3694 if ( tls_in.active.sock >= 0
3696 && tls_in.certificate_verified
3697 && cmd_list[CL_TLAU].is_mail_cmd
3700 cmd_list[CL_TLAU].is_mail_cmd = FALSE;
3702 for (auth_instance * au = auths; au; au = au->next)
3703 if (strcmpic(US"tls", au->driver_name) == 0)
3705 GET_OPTION("acl_smtp_auth");
3707 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3708 &user_msg, &log_msg)) != OK
3710 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3713 smtp_cmd_data = NULL;
3715 if (smtp_in_auth(au, &s, &ss) == OK)
3716 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3719 DEBUG(D_auth) debug_printf("tls auth not succeeded\n");
3720 #ifndef DISABLE_EVENT
3722 uschar * save_name = sender_host_authenticated, * logmsg;
3723 sender_host_authenticated = au->name;
3724 if ((logmsg = event_raise(event_action, US"auth:fail", s, NULL)))
3725 log_write(0, LOG_MAIN, "%s", logmsg);
3726 sender_host_authenticated = save_name;
3736 switch(smtp_read_command(
3737 #ifndef DISABLE_PIPE_CONNECT
3738 !fl.pipe_connect_acceptable,
3742 GETC_BUFFER_UNLIMITED))
3744 /* The AUTH command is not permitted to occur inside a transaction, and may
3745 occur successfully only once per connection. Actually, that isn't quite
3746 true. When TLS is started, all previous information about a connection must
3747 be discarded, so a new AUTH is permitted at that time.
3749 AUTH may only be used when it has been advertised. However, it seems that
3750 there are clients that send AUTH when it hasn't been advertised, some of
3751 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3752 So there's a get-out that allows this to happen.
3754 AUTH is initially labelled as a "nonmail command" so that one occurrence
3755 doesn't get counted. We change the label here so that multiple failing
3756 AUTHS will eventually hit the nonmail threshold. */
3760 authentication_failed = TRUE;
3761 cmd_list[CL_AUTH].is_mail_cmd = FALSE;
3763 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
3765 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3766 US"AUTH command used when not advertised");
3769 if (sender_host_authenticated)
3771 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3772 US"already authenticated");
3777 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3778 US"not permitted in mail transaction");
3784 GET_OPTION("acl_smtp_auth");
3786 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3787 &user_msg, &log_msg)) != OK
3790 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3794 /* Find the name of the requested authentication mechanism. */
3797 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
3798 if (!isalnum(c) && c != '-' && c != '_')
3800 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3801 US"invalid character in authentication mechanism name");
3805 /* If not at the end of the line, we must be at white space. Terminate the
3806 name and move the pointer on to any data that may be present. */
3810 *smtp_cmd_data++ = 0;
3811 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3814 /* Search for an authentication mechanism which is configured for use
3815 as a server and which has been advertised (unless, sigh, allow_auth_
3816 unadvertised is set). */
3820 uschar * smtp_resp, * errmsg;
3822 for (au = auths; au; au = au->next)
3823 if (strcmpic(s, au->public_name) == 0 && au->server &&
3824 (au->advertised || f.allow_auth_unadvertised))
3829 int rc = smtp_in_auth(au, &smtp_resp, &errmsg);
3831 smtp_printf("%s\r\n", SP_NO_MORE, smtp_resp);
3834 uschar * logmsg = NULL;
3835 #ifndef DISABLE_EVENT
3836 {uschar * save_name = sender_host_authenticated;
3837 sender_host_authenticated = au->name;
3838 logmsg = event_raise(event_action, US"auth:fail", smtp_resp, NULL);
3839 sender_host_authenticated = save_name;
3843 log_write(0, LOG_MAIN|LOG_REJECT, "%s", logmsg);
3845 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3846 au->name, host_and_ident(FALSE), errmsg);
3850 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3851 string_sprintf("%s authentication mechanism not supported", s));
3854 break; /* AUTH_CMD */
3856 /* The HELO/EHLO commands are permitted to appear in the middle of a
3857 session as well as at the beginning. They have the effect of a reset in
3858 addition to their other functions. Their absence at the start cannot be
3859 taken to be an error.
3863 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3864 or 502 failure replies MUST be returned as appropriate. The SMTP
3865 server MUST stay in the same state after transmitting these replies
3866 that it was in before the EHLO was received.
3868 Therefore, we do not do the reset until after checking the command for
3869 acceptability. This change was made for Exim release 4.11. Previously
3870 it did the reset first. */
3883 HELO_EHLO: /* Common code for HELO and EHLO */
3884 cmd_list[CL_HELO].is_mail_cmd = FALSE;
3885 cmd_list[CL_EHLO].is_mail_cmd = FALSE;
3887 /* Reject the HELO if its argument was invalid or non-existent. A
3888 successful check causes the argument to be saved in malloc store. */
3890 if (!check_helo(smtp_cmd_data))
3892 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", SP_NO_MORE, hello);
3894 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3895 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3896 *smtp_cmd_argument == 0 ? US"(no argument given)" :
3897 string_printing(smtp_cmd_argument));
3899 if (++synprot_error_count > smtp_max_synprot_errors)
3901 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3902 "syntax or protocol errors (last command was \"%s\", %Y)",
3903 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3912 /* If sender_host_unknown is true, we have got here via the -bs interface,
3913 not called from inetd. Otherwise, we are running an IP connection and the
3914 host address will be set. If the helo name is the primary name of this
3915 host and we haven't done a reverse lookup, force one now. If helo_verify_required
3916 is set, ensure that the HELO name matches the actual host. If helo_verify
3917 is set, do the same check, but softly. */
3919 if (!f.sender_host_unknown)
3921 BOOL old_helo_verified = f.helo_verified;
3922 uschar *p = smtp_cmd_data;
3924 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3927 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3928 because otherwise the log can be confusing. */
3930 if ( !sender_host_name
3931 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3932 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
3933 (void)host_name_lookup();
3935 /* Rebuild the fullhost info to include the HELO name (and the real name
3936 if it was looked up.) */
3938 host_build_sender_fullhost(); /* Rebuild */
3939 set_process_info("handling%s incoming connection from %s",
3940 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
3942 /* Verify if configured. This doesn't give much security, but it does
3943 make some people happy to be able to do it. If helo_verify_required is set,
3944 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3945 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3946 now obsolescent, since the verification can now be requested selectively
3949 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
3950 if (fl.helo_verify_required || fl.helo_verify)
3952 BOOL tempfail = !smtp_verify_helo();
3953 if (!f.helo_verified)
3955 if (fl.helo_verify_required)
3957 smtp_printf("%d %s argument does not match calling host\r\n", SP_NO_MORE,
3958 tempfail? 451 : 550, hello);
3959 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3960 tempfail? "temporarily " : "",
3961 hello, sender_helo_name, host_and_ident(FALSE));
3962 f.helo_verified = old_helo_verified;
3963 break; /* End of HELO/EHLO processing */
3965 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3966 "helo_try_verify_hosts\n", hello);
3972 /* set up SPF context */
3973 spf_conn_init(sender_helo_name, sender_host_address);
3976 /* Apply an ACL check if one is defined; afterwards, recheck
3977 synchronization in case the client started sending in a delay. */
3979 GET_OPTION("acl_smtp_helo");
3981 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3982 &user_msg, &log_msg)) != OK)
3984 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3985 sender_helo_name = NULL;
3986 host_build_sender_fullhost(); /* Rebuild */
3989 #ifndef DISABLE_PIPE_CONNECT
3990 else if (!fl.pipe_connect_acceptable && !check_sync())
3992 else if (!check_sync())
3996 /* Generate an OK reply. The default string includes the ident if present,
3997 and also the IP address if present. Reflecting back the ident is intended
3998 as a deterrent to mail forgers. For maximum efficiency, and also because
3999 some broken systems expect each response to be in a single packet, arrange
4000 that the entire reply is sent in one write(). */
4002 fl.auth_advertised = FALSE;
4003 f.smtp_in_pipelining_advertised = FALSE;
4005 fl.tls_advertised = FALSE;
4007 fl.dsn_advertised = FALSE;
4009 fl.smtputf8_advertised = FALSE;
4012 /* Expand the per-connection message count limit option */
4013 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4015 smtp_code = US"250 "; /* Default response code plus space*/
4018 /* sender_host_name below will be tainted, so save on copy when we hit it */
4019 g = string_get_tainted(24, GET_TAINTED);
4020 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4022 smtp_active_hostname,
4023 sender_ident ? sender_ident : US"",
4024 sender_ident ? US" at " : US"",
4025 sender_host_name ? sender_host_name : sender_helo_name);
4027 if (sender_host_address)
4028 g = string_fmt_append(g, " [%s]", sender_host_address);
4031 /* A user-supplied EHLO greeting may not contain more than one line. Note
4032 that the code returned by smtp_message_code() includes the terminating
4033 whitespace character. */
4039 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4040 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4041 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4043 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4044 "newlines: message truncated: %s", string_printing(s));
4047 g = string_cat(NULL, s);
4050 g = string_catn(g, US"\r\n", 2);
4052 /* If we received EHLO, we must create a multiline response which includes
4053 the functions supported. */
4057 g->s[3] = '-'; /* overwrite the space after the SMTP response code */
4059 /* I'm not entirely happy with this, as an MTA is supposed to check
4060 that it has enough room to accept a message of maximum size before
4061 it sends this. However, there seems little point in not sending it.
4062 The actual size check happens later at MAIL FROM time. By postponing it
4063 till then, VRFY and EXPN can be used after EHLO when space is short. */
4065 if (thismessage_size_limit > 0)
4066 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4067 thismessage_size_limit);
4070 g = string_catn(g, smtp_code, 3);
4071 g = string_catn(g, US"-SIZE\r\n", 7);
4074 #ifndef DISABLE_ESMTP_LIMITS
4075 if ( (smtp_mailcmd_max > 0 || recipients_max_expanded > 0)
4076 && verify_check_host(&limits_advertise_hosts) == OK)
4078 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4079 if (smtp_mailcmd_max > 0)
4080 g = string_fmt_append(g, " MAILMAX=%d", smtp_mailcmd_max);
4081 if (recipients_max_expanded > 0)
4082 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max_expanded);
4083 g = string_catn(g, US"\r\n", 2);
4087 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4088 clean; if it has an 8-bit character in its hand, it just sends it. It
4089 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4090 However, some users want this option simply in order to stop MUAs
4091 mangling messages that contain top-bit-set characters. It is therefore
4092 provided as an option. */
4094 if (accept_8bitmime)
4096 g = string_catn(g, smtp_code, 3);
4097 g = string_catn(g, US"-8BITMIME\r\n", 11);
4100 /* Advertise DSN support if configured to do so. */
4101 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4103 g = string_catn(g, smtp_code, 3);
4104 g = string_catn(g, US"-DSN\r\n", 6);
4105 fl.dsn_advertised = TRUE;
4108 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4109 permitted to issue them; a check is made when any host actually tries. */
4111 GET_OPTION("acl_smtp_etrn");
4114 g = string_catn(g, smtp_code, 3);
4115 g = string_catn(g, US"-ETRN\r\n", 7);
4117 GET_OPTION("acl_smtp_vrfy");
4120 g = string_catn(g, smtp_code, 3);
4121 g = string_catn(g, US"-VRFY\r\n", 7);
4123 GET_OPTION("acl_smtp_expn");
4126 g = string_catn(g, smtp_code, 3);
4127 g = string_catn(g, US"-EXPN\r\n", 7);
4130 /* Exim is quite happy with pipelining, so let the other end know that
4131 it is safe to use it, unless advertising is disabled. */
4133 if ( f.pipelining_enable
4134 && verify_check_host(&pipelining_advertise_hosts) == OK)
4136 g = string_catn(g, smtp_code, 3);
4137 g = string_catn(g, US"-PIPELINING\r\n", 13);
4138 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4139 f.smtp_in_pipelining_advertised = TRUE;
4141 #ifndef DISABLE_PIPE_CONNECT
4142 if (fl.pipe_connect_acceptable)
4144 f.smtp_in_early_pipe_advertised = TRUE;
4145 g = string_catn(g, smtp_code, 3);
4146 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4152 /* If any server authentication mechanisms are configured, advertise
4153 them if the current host is in auth_advertise_hosts. The problem with
4154 advertising always is that some clients then require users to
4155 authenticate (and aren't configurable otherwise) even though it may not
4156 be necessary (e.g. if the host is in host_accept_relay).
4158 RFC 2222 states that SASL mechanism names contain only upper case
4159 letters, so output the names in upper case, though we actually recognize
4160 them in either case in the AUTH command. */
4164 && !sender_host_authenticated
4166 && verify_check_host(&auth_advertise_hosts) == OK
4170 for (auth_instance * au = auths; au; au = au->next)
4172 au->advertised = FALSE;
4175 DEBUG(D_auth+D_expand) debug_printf_indent(
4176 "Evaluating advertise_condition for %s %s athenticator\n",
4177 au->name, au->public_name);
4178 if ( !au->advertise_condition
4179 || expand_check_condition(au->advertise_condition, au->name,
4186 g = string_catn(g, smtp_code, 3);
4187 g = string_catn(g, US"-AUTH", 5);
4189 fl.auth_advertised = TRUE;
4191 saveptr = gstring_length(g);
4192 g = string_catn(g, US" ", 1);
4193 g = string_cat(g, au->public_name);
4194 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4195 au->advertised = TRUE;
4200 if (!first) g = string_catn(g, US"\r\n", 2);
4203 /* RFC 3030 CHUNKING */
4205 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4207 g = string_catn(g, smtp_code, 3);
4208 g = string_catn(g, US"-CHUNKING\r\n", 11);
4209 f.chunking_offered = TRUE;
4210 chunking_state = CHUNKING_OFFERED;
4213 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4214 if it has been included in the binary, and the host matches
4215 tls_advertise_hosts. We must *not* advertise if we are already in a
4216 secure connection. */
4219 if (tls_in.active.sock < 0 &&
4220 verify_check_host(&tls_advertise_hosts) != FAIL)
4222 g = string_catn(g, smtp_code, 3);
4223 g = string_catn(g, US"-STARTTLS\r\n", 11);
4224 fl.tls_advertised = TRUE;
4227 #ifdef EXPERIMENTAL_XCLIENT
4228 if (proxy_session || verify_check_host(&hosts_xclient) != FAIL)
4230 g = string_catn(g, smtp_code, 3);
4231 g = xclient_smtp_advertise_str(g);
4234 #ifndef DISABLE_PRDR
4235 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4238 g = string_catn(g, smtp_code, 3);
4239 g = string_catn(g, US"-PRDR\r\n", 7);
4244 if ( accept_8bitmime
4245 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4247 g = string_catn(g, smtp_code, 3);
4248 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4249 fl.smtputf8_advertised = TRUE;
4253 /* Finish off the multiline reply with one that is always available. */
4255 g = string_catn(g, smtp_code, 3);
4256 g = string_catn(g, US" HELP\r\n", 7);
4259 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4264 int len = len_string_from_gstring(g, &ehlo_resp);
4266 if (tls_in.active.sock >= 0)
4267 (void) tls_write(NULL, ehlo_resp, len,
4268 # ifndef DISABLE_PIPE_CONNECT
4269 fl.pipe_connect_acceptable && pipeline_connect_sends());
4275 (void) fwrite(ehlo_resp, 1, len, smtp_out);
4277 DEBUG(D_receive) for (const uschar * t, * s = ehlo_resp;
4278 s && (t = Ustrchr(s, '\r'));
4279 s = t + 2) /* \r\n */
4280 debug_printf("%s %.*s\n",
4281 s == g->s ? "SMTP>>" : " ",
4283 fl.helo_seen = TRUE;
4286 /* Reset the protocol and the state, abandoning any previous message. */
4288 (sender_host_address ? protocols : protocols_local)
4290 ? pextend + (sender_host_authenticated ? pauthed : 0)
4292 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4294 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4295 reset_point = smtp_reset(reset_point);
4297 break; /* HELO/EHLO */
4299 #ifdef EXPERIMENTAL_XCLIENT
4302 BOOL fatal = fl.helo_seen;
4307 smtp_mailcmd_count++;
4309 if ((errmsg = xclient_smtp_command(smtp_cmd_data, &resp, &fatal)))
4311 done = synprot_error(L_smtp_syntax_error, resp, NULL, errmsg);
4314 smtp_printf("%d %s\r\n", SP_NO_MORE, resp, errmsg);
4315 log_write(0, LOG_MAIN|LOG_REJECT, "rejected XCLIENT from %s: %s",
4316 host_and_ident(FALSE), errmsg);
4320 fl.helo_seen = FALSE; /* Require another EHLO */
4321 smtp_code = string_sprintf("%d", resp);
4323 /*XXX unclear in spec. if this needs to be an ESMTP banner,
4324 nor whether we get the original client's HELO after (or a proxy fake).
4325 We require that we do; the following HELO/EHLO handling will set
4326 sender_helo_name as normal. */
4328 smtp_printf("%s XCLIENT success\r\n", SP_NO_MORE, smtp_code);
4330 break; /* XCLIENT */
4335 /* The MAIL command requires an address as an operand. All we do
4336 here is to parse it for syntactic correctness. The form "<>" is
4337 a special case which converts into an empty string. The start/end
4338 pointers in the original are not used further for this address, as
4339 it is the canonical extracted address which is all that is kept. */
4343 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4345 was_rej_mail = TRUE; /* Reset if accepted */
4346 env_mail_type_t * mail_args; /* Sanity check & validate args */
4349 if ( fl.helo_verify_required
4350 || verify_check_host(&hosts_require_helo) == OK)
4352 smtp_printf("503 HELO or EHLO required\r\n", SP_NO_MORE);
4353 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4354 "HELO/EHLO given", host_and_ident(FALSE));
4357 else if (smtp_mailcmd_max < 0)
4358 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4362 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4363 US"sender already given");
4367 if (!*smtp_cmd_data)
4369 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4370 US"MAIL must have an address operand");
4374 /* Check to see if the limit for messages per connection would be
4375 exceeded by accepting further messages. */
4377 if (smtp_mailcmd_max > 0 && smtp_mailcmd_count > smtp_mailcmd_max)
4379 smtp_printf("421 too many messages in this connection\r\n", SP_NO_MORE);
4380 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4381 "messages in one connection", host_and_ident(TRUE));
4385 /* Reset for start of message - even if this is going to fail, we
4386 obviously need to throw away any previous data. */
4388 cancel_cutthrough_connection(TRUE, US"MAIL received");
4389 reset_point = smtp_reset(reset_point);
4391 sender_data = recipient_data = NULL;
4393 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4395 if (fl.esmtp) for(;;)
4397 uschar *name, *value, *end;
4398 unsigned long int size;
4399 BOOL arg_error = FALSE;
4401 if (!extract_option(&name, &value)) break;
4403 for (mail_args = env_mail_type_list;
4404 mail_args->value != ENV_MAIL_OPT_NULL;
4407 if (strcmpic(name, mail_args->name) == 0)
4409 if (mail_args->need_value && strcmpic(value, US"") == 0)
4412 switch(mail_args->value)
4414 /* Handle SIZE= by reading the value. We don't do the check till later,
4415 in order to be able to log the sender address on failure. */
4416 case ENV_MAIL_OPT_SIZE:
4417 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4419 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4421 message_size = (int)size;
4427 /* If this session was initiated with EHLO and accept_8bitmime is set,
4428 Exim will have indicated that it supports the BODY=8BITMIME option. In
4429 fact, it does not support this according to the RFCs, in that it does not
4430 take any special action for forwarding messages containing 8-bit
4431 characters. That is why accept_8bitmime is not the default setting, but
4432 some sites want the action that is provided. We recognize both "8BITMIME"
4433 and "7BIT" as body types, but take no action. */
4434 case ENV_MAIL_OPT_BODY:
4435 if (accept_8bitmime) {
4436 if (strcmpic(value, US"8BITMIME") == 0)
4438 else if (strcmpic(value, US"7BIT") == 0)
4443 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4444 US"invalid data for BODY");
4447 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4453 /* Handle the two DSN options, but only if configured to do so (which
4454 will have caused "DSN" to be given in the EHLO response). The code itself
4455 is included only if configured in at build time. */
4457 case ENV_MAIL_OPT_RET:
4458 if (fl.dsn_advertised)
4460 /* Check if RET has already been set */
4463 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4464 US"RET can be specified once only");
4467 dsn_ret = strcmpic(value, US"HDRS") == 0
4469 : strcmpic(value, US"FULL") == 0
4472 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4473 /* Check for invalid invalid value, and exit with error */
4476 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4477 US"Value for RET is invalid");
4482 case ENV_MAIL_OPT_ENVID:
4483 if (fl.dsn_advertised)
4485 /* Check if the dsn envid has been already set */
4488 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4489 US"ENVID can be specified once only");
4492 dsn_envid = string_copy(value);
4493 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4497 /* Handle the AUTH extension. If the value given is not "<>" and either
4498 the ACL says "yes" or there is no ACL but the sending host is
4499 authenticated, we set it up as the authenticated sender. However, if the
4500 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4501 the condition is met. The value of AUTH is an xtext, which means that +,
4502 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4504 case ENV_MAIL_OPT_AUTH:
4505 if (Ustrcmp(value, "<>") != 0)
4510 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4512 /* Put back terminator overrides for error message */
4515 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4516 US"invalid data for AUTH");
4519 GET_OPTION("acl_smtp_mailauth");
4520 if (!acl_smtp_mailauth)
4522 ignore_msg = US"client not authenticated";
4523 rc = sender_host_authenticated ? OK : FAIL;
4527 ignore_msg = US"rejected by ACL";
4528 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4529 &user_msg, &log_msg);
4535 if (authenticated_by == NULL ||
4536 authenticated_by->mail_auth_condition == NULL ||
4537 expand_check_condition(authenticated_by->mail_auth_condition,
4538 authenticated_by->name, US"authenticator"))
4539 break; /* Accept the AUTH */
4541 ignore_msg = US"server_mail_auth_condition failed";
4542 if (authenticated_id != NULL)
4543 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4544 ignore_msg, authenticated_id);
4549 authenticated_sender = NULL;
4550 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4551 value, host_and_ident(TRUE), ignore_msg);
4554 /* Should only get DEFER or ERROR here. Put back terminator
4555 overrides for error message */
4560 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4567 #ifndef DISABLE_PRDR
4568 case ENV_MAIL_OPT_PRDR:
4570 prdr_requested = TRUE;
4575 case ENV_MAIL_OPT_UTF8:
4576 if (!fl.smtputf8_advertised)
4578 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4579 US"SMTPUTF8 used when not advertised");
4583 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4584 message_smtputf8 = allow_utf8_domains = TRUE;
4585 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4587 int old_pool = store_pool;
4588 store_pool = POOL_PERM;
4589 received_protocol = string_sprintf("utf8%s", received_protocol);
4590 store_pool = old_pool;
4595 /* No valid option. Stick back the terminator characters and break
4596 the loop. Do the name-terminator second as extract_option sets
4597 value==name when it found no equal-sign.
4598 An error for a malformed address will occur. */
4599 case ENV_MAIL_OPT_NULL:
4607 /* Break out of for loop if switch() had bad argument or
4608 when start of the email address is reached */
4609 if (arg_error) break;
4612 /* If we have passed the threshold for rate limiting, apply the current
4613 delay, and update it for next time, provided this is a limited host. */
4615 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4616 verify_check_host(&smtp_ratelimit_hosts) == OK)
4618 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4619 smtp_delay_mail/1000.0);
4620 millisleep((int)smtp_delay_mail);
4621 smtp_delay_mail *= smtp_rlm_factor;
4622 if (smtp_delay_mail > (double)smtp_rlm_limit)
4623 smtp_delay_mail = (double)smtp_rlm_limit;
4626 /* Now extract the address, first applying any SMTP-time rewriting. The
4627 TRUE flag allows "<>" as a sender address. */
4629 raw_sender = rewrite_existflags & rewrite_smtp
4630 /* deconst ok as smtp_cmd_data was not const */
4631 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4632 global_rewrite_rules)
4636 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4641 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4645 sender_address = raw_sender;
4647 /* If there is a configured size limit for mail, check that this message
4648 doesn't exceed it. The check is postponed to this point so that the sender
4651 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4653 smtp_printf("552 Message size exceeds maximum permitted\r\n", SP_NO_MORE);
4654 log_write(L_size_reject,
4655 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4656 "message too big: size%s=%d max=%d",
4658 host_and_ident(TRUE),
4659 (message_size == INT_MAX)? ">" : "",
4661 thismessage_size_limit);
4662 sender_address = NULL;
4666 /* Check there is enough space on the disk unless configured not to.
4667 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4668 plus the current message - i.e. we accept the message only if it won't
4669 reduce the space below the threshold. Add 5000 to the size to allow for
4670 overheads such as the Received: line and storing of recipients, etc.
4671 By putting the check here, even when SIZE is not given, it allow VRFY
4672 and EXPN etc. to be used when space is short. */
4674 if (!receive_check_fs(
4675 smtp_check_spool_space && message_size >= 0
4676 ? message_size + 5000 : 0))
4678 smtp_printf("452 Space shortage, please try later\r\n", SP_NO_MORE);
4679 sender_address = NULL;
4683 /* If sender_address is unqualified, reject it, unless this is a locally
4684 generated message, or the sending host or net is permitted to send
4685 unqualified addresses - typically local machines behaving as MUAs -
4686 in which case just qualify the address. The flag is set above at the start
4687 of the SMTP connection. */
4689 if (!sender_domain && *sender_address)
4690 if (f.allow_unqualified_sender)
4692 sender_domain = Ustrlen(sender_address) + 1;
4693 /* deconst ok as sender_address was not const */
4694 sender_address = US rewrite_address_qualify(sender_address, FALSE);
4695 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4700 smtp_printf("501 %s: sender address must contain a domain\r\n", SP_NO_MORE,
4702 log_write(L_smtp_syntax_error,
4703 LOG_MAIN|LOG_REJECT,
4704 "unqualified sender rejected: <%s> %s%s",
4706 host_and_ident(TRUE),
4708 sender_address = NULL;
4712 /* Apply an ACL check if one is defined, before responding. Afterwards,
4713 when pipelining is not advertised, do another sync check in case the ACL
4714 delayed and the client started sending in the meantime. */
4716 GET_OPTION("acl_smtp_mail");
4719 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4720 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4726 if (rc == OK || rc == DISCARD)
4728 BOOL more = pipeline_response();
4731 smtp_printf("%s%s%s", more, US"250 OK",
4732 #ifndef DISABLE_PRDR
4733 prdr_requested ? US", PRDR Requested" : US"",
4740 #ifndef DISABLE_PRDR
4742 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4744 smtp_user_msg(US"250", user_msg);
4746 smtp_delay_rcpt = smtp_rlr_base;
4747 f.recipients_discarded = (rc == DISCARD);
4748 was_rej_mail = FALSE;
4752 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4753 sender_address = NULL;
4758 /* The RCPT command requires an address as an operand. There may be any
4759 number of RCPT commands, specifying multiple recipients. We build them all
4760 into a data structure. The start/end values given by parse_extract_address
4761 are not used, as we keep only the extracted address. */
4765 /* We got really to many recipients. A check against configured
4766 limits is done later */
4767 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
4768 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
4770 was_rcpt = fl.rcpt_in_progress = TRUE;
4772 /* There must be a sender address; if the sender was rejected and
4773 pipelining was advertised, we assume the client was pipelining, and do not
4774 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4775 get the same treatment. */
4777 if (!sender_address)
4779 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4781 smtp_printf("503 sender not yet given\r\n", SP_NO_MORE);
4782 was_rej_mail = TRUE;
4786 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4787 US"sender not yet given");
4788 was_rcpt = FALSE; /* Not a valid RCPT */
4794 /* Check for an operand */
4796 if (!smtp_cmd_data[0])
4798 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4799 US"RCPT must have an address operand");
4804 /* Set the DSN flags orcpt and dsn_flags from the session*/
4808 if (fl.esmtp) for(;;)
4810 uschar *name, *value;
4812 if (!extract_option(&name, &value))
4815 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4817 /* Check whether orcpt has been already set */
4820 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4821 US"ORCPT can be specified once only");
4824 orcpt = string_copy(value);
4825 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4828 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4830 /* Check if the notify flags have been already set */
4833 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4834 US"NOTIFY can be specified once only");
4837 if (strcmpic(value, US"NEVER") == 0)
4838 dsn_flags |= rf_notify_never;
4845 while (*pp != 0 && *pp != ',') pp++;
4846 if (*pp == ',') *pp++ = 0;
4847 if (strcmpic(p, US"SUCCESS") == 0)
4849 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4850 dsn_flags |= rf_notify_success;
4852 else if (strcmpic(p, US"FAILURE") == 0)
4854 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4855 dsn_flags |= rf_notify_failure;
4857 else if (strcmpic(p, US"DELAY") == 0)
4859 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4860 dsn_flags |= rf_notify_delay;
4864 /* Catch any strange values */
4865 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4866 US"Invalid value for NOTIFY parameter");
4871 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
4875 /* Unknown option. Stick back the terminator characters and break
4876 the loop. An error for a malformed address will occur. */
4880 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4887 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4888 as a recipient address */
4890 recipient = rewrite_existflags & rewrite_smtp
4891 /* deconst ok as smtp_cmd_data was not const */
4892 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4893 global_rewrite_rules)
4896 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4897 &recipient_domain, FALSE)))
4899 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4904 /* If the recipient address is unqualified, reject it, unless this is a
4905 locally generated message. However, unqualified addresses are permitted
4906 from a configured list of hosts and nets - typically when behaving as
4907 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4908 really. The flag is set at the start of the SMTP connection.
4910 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4911 assumed this meant "reserved local part", but the revision of RFC 821 and
4912 friends now makes it absolutely clear that it means *mailbox*. Consequently
4913 we must always qualify this address, regardless. */
4915 if (!recipient_domain)
4916 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4923 /* Check maximum allowed */
4925 if ( rcpt_count+1 < 0
4926 || rcpt_count > recipients_max_expanded && recipients_max_expanded > 0)
4928 if (recipients_max_reject)
4931 smtp_printf("552 too many recipients\r\n", SP_NO_MORE);
4933 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4934 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4939 smtp_printf("452 too many recipients\r\n", SP_NO_MORE);
4941 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4942 "temporarily rejected: sender=<%s> %s", sender_address,
4943 host_and_ident(TRUE));
4950 /* If we have passed the threshold for rate limiting, apply the current
4951 delay, and update it for next time, provided this is a limited host. */
4953 if (rcpt_count > smtp_rlr_threshold &&
4954 verify_check_host(&smtp_ratelimit_hosts) == OK)
4956 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4957 smtp_delay_rcpt/1000.0);
4958 millisleep((int)smtp_delay_rcpt);
4959 smtp_delay_rcpt *= smtp_rlr_factor;
4960 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4961 smtp_delay_rcpt = (double)smtp_rlr_limit;
4964 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4965 for them. Otherwise, check the access control list for this recipient. As
4966 there may be a delay in this, re-check for a synchronization error
4967 afterwards, unless pipelining was advertised. */
4969 if (f.recipients_discarded)
4973 GET_OPTION("acl_smtp_rcpt");
4974 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4976 && !f.smtp_in_pipelining_advertised && !check_sync())
4980 /* The ACL was happy */
4984 BOOL more = pipeline_response();
4987 smtp_user_msg(US"250", user_msg);
4989 smtp_printf("250 Accepted\r\n", more);
4990 receive_add_recipient(recipient, -1);
4992 /* Set the dsn flags in the recipients_list */
4993 recipients_list[recipients_count-1].orcpt = orcpt;
4994 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
4996 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4997 recipients_list[recipients_count-1].orcpt,
4998 recipients_list[recipients_count-1].dsn_flags); */
5001 /* The recipient was discarded */
5003 else if (rc == DISCARD)
5006 smtp_user_msg(US"250", user_msg);
5008 smtp_printf("250 Accepted\r\n", SP_NO_MORE);
5011 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5012 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5013 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5014 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5015 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5018 /* Either the ACL failed the address, or it was deferred. */
5022 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5023 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5028 /* The DATA command is legal only if it follows successful MAIL FROM
5029 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5030 not counted as a protocol error if it follows RCPT (which must have been
5031 rejected if there are no recipients.) This function is complete when a
5032 valid DATA command is encountered.
5034 Note concerning the code used: RFC 2821 says this:
5036 - If there was no MAIL, or no RCPT, command, or all such commands
5037 were rejected, the server MAY return a "command out of sequence"
5038 (503) or "no valid recipients" (554) reply in response to the
5041 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5042 because it is the same whether pipelining is in use or not.
5044 If all the RCPT commands that precede DATA provoked the same error message
5045 (often indicating some kind of system error), it is helpful to include it
5046 with the DATA rejection (an idea suggested by Tony Finch). */
5053 if (chunking_state != CHUNKING_OFFERED)
5055 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5056 US"BDAT command used when CHUNKING not advertised");
5060 /* grab size, endmarker */
5062 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5064 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5065 US"missing size for BDAT command");
5068 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5069 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5070 chunking_data_left = chunking_datasize;
5071 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5072 (int)chunking_state, chunking_data_left);
5074 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
5083 f.bdat_readers_wanted = FALSE;
5085 DATA_BDAT: /* Common code for DATA and BDAT */
5086 #ifndef DISABLE_PIPE_CONNECT
5087 fl.pipe_connect_acceptable = FALSE;
5089 if (!discarded && recipients_count <= 0)
5091 if (fl.rcpt_smtp_response_same && rcpt_smtp_response)
5093 uschar *code = US"503";
5094 int len = Ustrlen(rcpt_smtp_response);
5095 smtp_respond(code, 3, SR_NOT_FINAL, US"All RCPT commands were rejected with "
5097 /* Responses from smtp_printf() will have \r\n on the end */
5098 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5099 rcpt_smtp_response[len-2] = 0;
5100 smtp_respond(code, 3, SR_NOT_FINAL, rcpt_smtp_response);
5102 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5103 smtp_printf("503 Valid RCPT command must precede %s\r\n", SP_NO_MORE,
5104 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5106 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5107 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5108 ? US"valid RCPT command must precede DATA"
5109 : US"valid RCPT command must precede BDAT");
5111 if (chunking_state > CHUNKING_OFFERED)
5113 bdat_push_receive_functions();
5119 if (toomany && recipients_max_reject)
5121 sender_address = NULL; /* This will allow a new MAIL without RSET */
5122 sender_address_unrewritten = NULL;
5123 smtp_printf("554 Too many recipients\r\n", SP_NO_MORE);
5125 if (chunking_state > CHUNKING_OFFERED)
5127 bdat_push_receive_functions();
5133 if (chunking_state > CHUNKING_OFFERED)
5134 rc = OK; /* There is no predata ACL or go-ahead output for BDAT */
5137 /* If there is a predata-ACL, re-check the synchronization afterwards,
5138 since the ACL may have delayed. To handle cutthrough delivery enforce a
5139 dummy call to get the DATA command sent. */
5141 GET_OPTION("acl_smtp_predata");
5142 if (!acl_smtp_predata && cutthrough.cctx.sock < 0)
5146 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5147 f.enable_dollar_recipients = TRUE;
5148 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5150 f.enable_dollar_recipients = FALSE;
5151 if (rc == OK && !check_sync())
5155 { /* Either the ACL failed the address, or it was deferred. */
5156 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5162 smtp_user_msg(US"354", user_msg);
5165 "354 Enter message, ending with \".\" on a line by itself\r\n", SP_NO_MORE);
5168 if (f.bdat_readers_wanted)
5169 bdat_push_receive_functions();
5172 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5173 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5174 US &on, sizeof(on));
5177 message_ended = END_NOTENDED; /* Indicate in middle of data */
5188 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5189 &start, &end, &recipient_domain, FALSE)))
5191 smtp_printf("501 %s\r\n", SP_NO_MORE, errmess);
5195 if (!recipient_domain)
5196 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5200 GET_OPTION("acl_smtp_vrfy");
5201 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5202 &user_msg, &log_msg)) != OK)
5203 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5207 address_item * addr = deliver_make_addr(address, FALSE);
5209 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5210 -1, -1, NULL, NULL, NULL))
5213 s = string_sprintf("250 <%s> is deliverable", address);
5217 s = (addr->user_message != NULL)?
5218 string_sprintf("451 <%s> %s", address, addr->user_message) :
5219 string_sprintf("451 Cannot resolve <%s> at this time", address);
5223 s = (addr->user_message != NULL)?
5224 string_sprintf("550 <%s> %s", address, addr->user_message) :
5225 string_sprintf("550 <%s> is not deliverable", address);
5226 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5227 smtp_cmd_argument, host_and_ident(TRUE));
5231 smtp_printf("%s\r\n", SP_NO_MORE, s);
5239 GET_OPTION("acl_smtp_expn");
5240 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5242 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5245 BOOL save_log_testing_mode = f.log_testing_mode;
5246 f.address_test_mode = f.log_testing_mode = TRUE;
5247 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5248 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5250 f.address_test_mode = FALSE;
5251 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5260 if (!fl.tls_advertised)
5262 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5263 US"STARTTLS command used when not advertised");
5267 /* Apply an ACL check if one is defined */
5269 GET_OPTION("acl_smtp_starttls");
5270 if ( acl_smtp_starttls
5271 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5272 &user_msg, &log_msg)) != OK
5275 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5279 /* RFC 2487 is not clear on when this command may be sent, though it
5280 does state that all information previously obtained from the client
5281 must be discarded if a TLS session is started. It seems reasonable to
5282 do an implied RSET when STARTTLS is received. */
5284 incomplete_transaction_log(US"STARTTLS");
5285 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5286 reset_point = smtp_reset(reset_point);
5288 cmd_list[CL_STLS].is_mail_cmd = FALSE;
5290 /* There's an attack where more data is read in past the STARTTLS command
5291 before TLS is negotiated, then assumed to be part of the secure session
5292 when used afterwards; we use segregated input buffers, so are not
5293 vulnerable, but we want to note when it happens and, for sheer paranoia,
5294 ensure that the buffer is "wiped".
5295 Pipelining sync checks will normally have protected us too, unless disabled
5296 by configuration. */
5301 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5302 if (tls_in.active.sock < 0)
5303 smtp_inend = smtp_inptr = smtp_inbuffer;
5304 /* and if TLS is already active, tls_server_start() should fail */
5307 /* There is nothing we value in the input buffer and if TLS is successfully
5308 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5309 fresh content into it. The buffer contains arbitrary content from an
5310 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5311 It seems safest to just wipe away the content rather than leave it as a
5312 target to jump to. */
5314 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5316 /* Attempt to start up a TLS session, and if successful, discard all
5317 knowledge that was obtained previously. At least, that's what the RFC says,
5318 and that's what happens by default. However, in order to work round YAEB,
5319 there is an option to remember the esmtp state. Sigh.
5321 We must allow for an extra EHLO command and an extra AUTH command after
5322 STARTTLS that don't add to the nonmail command count. */
5325 if ((rc = tls_server_start(&s)) == OK)
5327 if (!tls_remember_esmtp)
5328 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5329 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
5330 cmd_list[CL_AUTH].is_mail_cmd = TRUE;
5331 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
5332 if (sender_helo_name)
5334 sender_helo_name = NULL;
5335 host_build_sender_fullhost(); /* Rebuild */
5336 set_process_info("handling incoming TLS connection from %s",
5337 host_and_ident(FALSE));
5340 (sender_host_address ? protocols : protocols_local)
5342 ? pextend + (sender_host_authenticated ? pauthed : 0)
5344 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5347 sender_host_auth_pubname = sender_host_authenticated = NULL;
5348 authenticated_id = NULL;
5349 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5350 DEBUG(D_tls) debug_printf("TLS active\n");
5351 break; /* Successful STARTTLS */
5354 (void) smtp_log_tls_fail(s);
5356 /* Some local configuration problem was discovered before actually trying
5357 to do a TLS handshake; give a temporary error. */
5361 smtp_printf("454 TLS currently unavailable\r\n", SP_NO_MORE);
5365 /* Hard failure. Reject everything except QUIT or closed connection. One
5366 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5367 set, but we must still reject all incoming commands. Another is a handshake
5368 failure - and there may some encrypted data still in the pipe to us, which we
5369 see as garbage commands. */
5371 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5372 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5375 log_close_event(US"by EOF");
5376 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5380 /* It is perhaps arguable as to which exit ACL should be called here,
5381 but as it is probably a situation that almost never arises, it
5382 probably doesn't matter. We choose to call the real QUIT ACL, which in
5383 some sense is perhaps "right". */
5386 f.smtp_in_quit = TRUE;
5388 GET_OPTION("acl_smtp_quit");
5390 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5391 &log_msg)) == ERROR))
5392 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5395 smtp_respond(US"221", 3, SR_FINAL, user_msg);
5397 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
5398 log_close_event(US"by QUIT");
5403 smtp_printf("554 Security failure\r\n", SP_NO_MORE);
5406 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5411 /* The ACL for QUIT is provided for gathering statistical information or
5412 similar; it does not affect the response code, but it can supply a custom
5416 smtp_quit_handler(&user_msg, &log_msg);
5422 smtp_rset_handler();
5423 cancel_cutthrough_connection(TRUE, US"RSET received");
5424 reset_point = smtp_reset(reset_point);
5431 smtp_printf("250 OK\r\n", SP_NO_MORE);
5435 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5436 used, a check will be done for permitted hosts. Show STARTTLS only if not
5437 already in a TLS session and if it would be advertised in the EHLO
5442 smtp_printf("214-Commands supported:\r\n214", SP_MORE);
5443 smtp_printf(" AUTH", SP_MORE);
5445 if (tls_in.active.sock < 0 &&
5446 verify_check_host(&tls_advertise_hosts) != FAIL)
5447 smtp_printf(" STARTTLS", SP_MORE);
5449 smtp_printf(" HELO EHLO MAIL RCPT DATA BDAT", SP_MORE);
5450 smtp_printf(" NOOP QUIT RSET HELP", SP_MORE);
5451 if (acl_smtp_etrn) smtp_printf(" ETRN", SP_MORE);
5452 if (acl_smtp_expn) smtp_printf(" EXPN", SP_MORE);
5453 if (acl_smtp_vrfy) smtp_printf(" VRFY", SP_MORE);
5454 #ifdef EXPERIMENTAL_XCLIENT
5455 if (proxy_session || verify_check_host(&hosts_xclient) != FAIL)
5456 smtp_printf(" XCLIENT", SP_MORE);
5458 smtp_printf("\r\n", SP_NO_MORE);
5463 incomplete_transaction_log(US"connection lost");
5464 smtp_notquit_exit(US"connection-lost", US"421",
5465 US"%s lost input connection", smtp_active_hostname);
5467 /* Don't log by default unless in the middle of a message, as some mailers
5468 just drop the call rather than sending QUIT, and it clutters up the logs.
5471 if (sender_address || recipients_count > 0)
5472 log_write(L_lost_incoming_connection, LOG_MAIN,
5473 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5474 f.sender_host_unknown ? "EOF" : "disconnection",
5475 f.tcp_in_fastopen_logged
5478 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5480 host_and_ident(FALSE), smtp_read_error,
5481 string_timesince(&smtp_connection_start)
5485 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5486 smtp_get_connection_info(),
5487 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5489 string_timesince(&smtp_connection_start)
5500 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5501 US"ETRN is not permitted inside a transaction");
5505 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5506 host_and_ident(FALSE));
5508 GET_OPTION("acl_smtp_etrn");
5509 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5510 &user_msg, &log_msg)) != OK)
5512 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5516 /* Compute the serialization key for this command. */
5518 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5520 /* If a command has been specified for running as a result of ETRN, we
5521 permit any argument to ETRN. If not, only the # standard form is permitted,
5522 since that is strictly the only kind of ETRN that can be implemented
5523 according to the RFC. */
5525 GET_OPTION("smtp_etrn_command");
5526 if (smtp_etrn_command)
5530 etrn_command = smtp_etrn_command;
5531 deliver_domain = smtp_cmd_data;
5532 rc = transport_set_up_command(&argv, smtp_etrn_command, TSUC_EXPAND_ARGS, 0, NULL,
5533 US"ETRN processing", &error);
5534 deliver_domain = NULL;
5537 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5539 smtp_printf("458 Internal failure\r\n", SP_NO_MORE);
5544 /* Else set up to call Exim with the -R option. */
5548 if (*smtp_cmd_data++ != '#')
5550 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5551 US"argument must begin with #");
5554 etrn_command = US"exim -R";
5555 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5556 *queue_name ? 4 : 2,
5557 US"-R", smtp_cmd_data,
5558 US"-MCG", queue_name);
5561 /* If we are host-testing, don't actually do anything. */
5567 debug_printf("ETRN command is: %s\n", etrn_command);
5568 debug_printf("ETRN command execution skipped\n");
5570 if (user_msg == NULL) smtp_printf("250 OK\r\n", SP_NO_MORE);
5571 else smtp_user_msg(US"250", user_msg);
5576 /* If ETRN queue runs are to be serialized, check the database to
5577 ensure one isn't already running. */
5579 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5581 smtp_printf("458 Already processing %s\r\n", SP_NO_MORE, smtp_cmd_data);
5585 /* Fork a child process and run the command. We don't want to have to
5586 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5587 forking. It should be set that way anyway for external incoming SMTP,
5588 but we save and restore to be tidy. If serialization is required, we
5589 actually run the command in yet another process, so we can wait for it
5590 to complete and then remove the serialization lock. */
5592 oldsignal = signal(SIGCHLD, SIG_IGN);
5594 if ((pid = exim_fork(US"etrn-command")) == 0)
5596 smtp_input = FALSE; /* This process is not associated with the */
5597 (void)fclose(smtp_in); /* SMTP call any more. */
5598 (void)fclose(smtp_out);
5600 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5602 /* If not serializing, do the exec right away. Otherwise, fork down
5603 into another process. */
5605 if ( !smtp_etrn_serialize
5606 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5608 DEBUG(D_exec) debug_print_argv(argv);
5609 exim_nullstd(); /* Ensure std{in,out,err} exist */
5610 /* argv[0] should be untainted, from child_exec_exim() */
5611 execv(CS argv[0], (char *const *)argv);
5612 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5613 etrn_command, strerror(errno));
5614 _exit(EXIT_FAILURE); /* paranoia */
5617 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5618 is, we are in the first subprocess, after forking again. All we can do
5619 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5620 complete, before removing the serialization. */
5623 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5624 "failed: %s", strerror(errno));
5628 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5630 (void)wait(&status);
5631 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5635 enq_end(etrn_serialize_key);
5636 exim_underbar_exit(EXIT_SUCCESS);
5639 /* Back in the top level SMTP process. Check that we started a subprocess
5640 and restore the signal state. */
5644 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5646 smtp_printf("458 Unable to fork process\r\n", SP_NO_MORE);
5647 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5651 smtp_printf("250 OK\r\n", SP_NO_MORE);
5653 smtp_user_msg(US"250", user_msg);
5655 signal(SIGCHLD, oldsignal);
5660 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5661 US"unexpected argument data");
5665 /* This currently happens only for NULLs, but could be extended. */
5668 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5669 US"NUL character(s) present (shown as '?')");
5670 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5678 unsigned nchars = 150;
5679 uschar * buf = receive_getbuf(&nchars); /* destructive read */
5681 incomplete_transaction_log(US"sync failure");
5682 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5683 "(next input sent too soon: pipelining was%s advertised): "
5684 "rejected \"%s\" %s next input=\"%s\" (%u bytes)",
5685 f.smtp_in_pipelining_advertised ? "" : " not",
5686 smtp_cmd_buffer, host_and_ident(TRUE),
5687 string_printing(buf), nchars);
5688 smtp_notquit_exit(US"synchronization-error", US"554",
5689 US"SMTP synchronization error");
5690 done = 1; /* Pretend eof - drops connection */
5695 case TOO_MANY_NONMAIL_CMD:
5696 s = smtp_cmd_buffer;
5697 while (*s && !isspace(*s)) s++;
5698 incomplete_transaction_log(US"too many non-mail commands");
5699 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5700 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5701 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5702 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5703 done = 1; /* Pretend eof - drops connection */
5706 #ifdef SUPPORT_PROXY
5707 case PROXY_FAIL_IGNORE_CMD:
5708 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", SP_NO_MORE);
5713 if (unknown_command_count++ >= smtp_max_unknown_commands)
5715 log_write(L_smtp_syntax_error, LOG_MAIN,
5716 "SMTP syntax error in \"%s\" %s %s",
5717 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5718 US"unrecognized command");
5719 incomplete_transaction_log(US"unrecognized command");
5720 smtp_notquit_exit(US"bad-commands", US"500",
5721 US"Too many unrecognized commands");
5723 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5724 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5725 string_printing(smtp_cmd_buffer));
5728 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5729 US"unrecognized command");
5733 /* This label is used by goto's inside loops that want to break out to
5734 the end of the command-processing loop. */
5737 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5738 last_was_rcpt = was_rcpt; /* protocol error handling */
5741 return done - 2; /* Convert yield values */
5747 authres_smtpauth(gstring * g)
5749 if (!sender_host_authenticated)
5752 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5754 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
5755 g = authenticated_id
5756 ? string_append(g, 2, US") x509.auth=", authenticated_id)
5757 : string_cat(g, US") reason=x509.auth");
5759 g = authenticated_id
5760 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
5761 : string_cat(g, US", no id saved)");
5763 if (authenticated_sender)
5764 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5772 /* End of smtp_in.c */