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 Uskip_whitespace(&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 #ifdef EXPERIMENTAL_WELLKNOWN
1952 bsmtp_transaction_linecount = receive_linecount;
1957 f.smtp_in_quit = TRUE;
1964 /* The function moan_smtp_batch() does not return. */
1965 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1970 /* The function moan_smtp_batch() does not return. */
1971 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1976 /* The function moan_smtp_batch() does not return. */
1977 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1982 return done - 2; /* Convert yield values */
1990 smtp_log_tls_fail(const uschar * errstr)
1992 const uschar * conn_info = smtp_get_connection_info();
1994 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
1995 /* I'd like to get separated H= here, but too hard for now */
1997 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2011 socklen_t len = sizeof(is_fastopen);
2013 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2014 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2016 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2021 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2022 f.tcp_in_fastopen = TRUE;
2025 else DEBUG(D_receive)
2026 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2028 # elif defined(TCP_INFO)
2029 struct tcp_info tinfo;
2030 socklen_t len = sizeof(tinfo);
2032 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2033 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2034 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2037 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2038 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2042 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2045 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2046 f.tcp_in_fastopen = TRUE;
2048 else DEBUG(D_receive)
2049 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2056 log_connect_tls_drop(const uschar * what, const uschar * log_msg)
2058 if (log_reject_target)
2060 gstring * g = s_tlslog(NULL);
2061 uschar * tls = string_from_gstring(g);
2063 log_write(L_connection_reject,
2064 log_reject_target, "%s%s%s dropped by %s%s%s",
2065 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
2066 host_and_ident(TRUE),
2069 log_msg ? US": " : US"", log_msg);
2074 /*************************************************
2075 * Start an SMTP session *
2076 *************************************************/
2078 /* This function is called at the start of an SMTP session. Thereafter,
2079 smtp_setup_msg() is called to initiate each separate message. This
2080 function does host-specific testing, and outputs the banner line.
2083 Returns: FALSE if the session can not continue; something has
2084 gone wrong, or the connection to the host is blocked
2088 smtp_start_session(void)
2091 uschar *user_msg, *log_msg;
2096 gettimeofday(&smtp_connection_start, NULL);
2097 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2098 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2101 /* Default values for certain variables */
2103 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2104 smtp_mailcmd_count = 0;
2105 count_nonmail = TRUE_UNSET;
2106 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2107 smtp_delay_mail = smtp_rlm_base;
2108 fl.auth_advertised = FALSE;
2109 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2110 f.pipelining_enable = TRUE;
2111 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2112 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2114 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2115 authentication settings from -oMaa to remain in force. */
2117 if (!host_checking && !f.sender_host_notsocket)
2118 sender_host_auth_pubname = sender_host_authenticated = NULL;
2119 authenticated_by = NULL;
2122 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2123 tls_in.ourcert = tls_in.peercert = NULL;
2125 tls_in.ocsp = OCSP_NOT_REQ;
2126 fl.tls_advertised = FALSE;
2128 fl.dsn_advertised = FALSE;
2130 fl.smtputf8_advertised = FALSE;
2133 /* Reset ACL connection variables */
2137 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2139 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, GET_TAINTED);
2141 smtp_cmd_buffer[0] = 0;
2142 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2144 /* For batched input, the protocol setting can be overridden from the
2145 command line by a trusted caller. */
2147 if (smtp_batched_input)
2149 if (!received_protocol) received_protocol = US"local-bsmtp";
2152 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2153 reset later if any of EHLO/AUTH/STARTTLS are received. */
2157 (sender_host_address ? protocols : protocols_local) [pnormal];
2159 /* Set up the buffer for inputting using direct read() calls, and arrange to
2160 call the local functions instead of the standard C ones. */
2164 receive_getc = smtp_getc;
2165 receive_getbuf = smtp_getbuf;
2166 receive_get_cache = smtp_get_cache;
2167 receive_hasc = smtp_hasc;
2168 receive_ungetc = smtp_ungetc;
2169 receive_feof = smtp_feof;
2170 receive_ferror = smtp_ferror;
2171 lwr_receive_getc = NULL;
2172 lwr_receive_getbuf = NULL;
2173 lwr_receive_hasc = NULL;
2174 lwr_receive_ungetc = NULL;
2176 /* Set up the message size limit; this may be host-specific */
2178 GET_OPTION("message_size_limit");
2179 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2180 if (expand_string_message)
2182 if (thismessage_size_limit == -1)
2183 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2184 "%s", expand_string_message);
2186 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2187 "%s", expand_string_message);
2188 smtp_closedown(US"Temporary local problem - please try later");
2192 /* When a message is input locally via the -bs or -bS options, sender_host_
2193 unknown is set unless -oMa was used to force an IP address, in which case it
2194 is checked like a real remote connection. When -bs is used from inetd, this
2195 flag is not set, causing the sending host to be checked. The code that deals
2196 with IP source routing (if configured) is never required for -bs or -bS and
2197 the flag sender_host_notsocket is used to suppress it.
2199 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2200 reserve for certain hosts and/or networks. */
2202 if (!f.sender_host_unknown)
2205 BOOL reserved_host = FALSE;
2207 /* Look up IP options (source routing info) on the socket if this is not an
2208 -oMa "host", and if any are found, log them and drop the connection.
2210 Linux (and others now, see below) is different to everyone else, so there
2211 has to be some conditional compilation here. Versions of Linux before 2.1.15
2212 used a structure whose name was "options". Somebody finally realized that
2213 this name was silly, and it got changed to "ip_options". I use the
2214 newer name here, but there is a fudge in the script that sets up os.h
2215 to define a macro in older Linux systems.
2217 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2218 glibc 2, which has chosen ip_opts for the structure name. This is now
2219 really a glibc thing rather than a Linux thing, so the condition name
2220 has been changed to reflect this. It is relevant also to GNU/Hurd.
2222 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2223 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2224 a special macro defined in the os.h file.
2226 Some DGUX versions on older hardware appear not to support IP options at
2227 all, so there is now a general macro which can be set to cut out this
2230 How to do this properly in IPv6 is not yet known. */
2232 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2234 # ifdef GLIBC_IP_OPTIONS
2235 # if (!defined __GLIBC__) || (__GLIBC__ < 2)
2240 # elif defined DARWIN_IP_OPTIONS
2246 if (!host_checking && !f.sender_host_notsocket)
2249 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2250 struct ip_options *ipopt = store_get(optlen, GET_UNTAINTED);
2251 # elif OPTSTYLE == 2
2252 struct ip_opts ipoptblock;
2253 struct ip_opts *ipopt = &ipoptblock;
2254 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2256 struct ipoption ipoptblock;
2257 struct ipoption *ipopt = &ipoptblock;
2258 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2261 /* Occasional genuine failures of getsockopt() have been seen - for
2262 example, "reset by peer". Therefore, just log and give up on this
2263 call, unless the error is ENOPROTOOPT. This error is given by systems
2264 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2265 of writing. So for that error, carry on - we just can't do an IP options
2268 DEBUG(D_receive) debug_printf("checking for IP options\n");
2270 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2273 if (errno != ENOPROTOOPT)
2275 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2276 host_and_ident(FALSE), strerror(errno));
2277 smtp_printf("451 SMTP service not available\r\n", SP_NO_MORE);
2282 /* Deal with any IP options that are set. On the systems I have looked at,
2283 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2284 more logging data than will fit in big_buffer. Nevertheless, after somebody
2285 questioned this code, I've added in some paranoid checking. */
2287 else if (optlen > 0)
2289 uschar * p = big_buffer;
2290 uschar * pend = big_buffer + big_buffer_size;
2293 struct in_addr addr;
2296 uschar * optstart = US (ipopt->__data);
2297 # elif OPTSTYLE == 2
2298 uschar * optstart = US (ipopt->ip_opts);
2300 uschar * optstart = US (ipopt->ipopt_list);
2303 DEBUG(D_receive) debug_printf("IP options exist\n");
2305 Ustrcpy(p, "IP options on incoming call:");
2308 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2323 string_format(p, pend-p, " %s [@%s",
2324 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2325 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr)))))
2326 # elif OPTSTYLE == 2
2327 string_format(p, pend-p, " %s [@%s",
2328 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2329 inet_ntoa(ipopt->ip_dst))
2331 string_format(p, pend-p, " %s [@%s",
2332 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2333 inet_ntoa(ipopt->ipopt_dst))
2342 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2344 while (optcount-- > 0)
2346 memcpy(&addr, adptr, sizeof(addr));
2347 if (!string_format(p, pend - p - 1, "%s%s",
2348 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2354 adptr += sizeof(struct in_addr);
2362 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2365 for (int i = 0; i < opt[1]; i++)
2366 p += sprintf(CS p, "%2.2x ", opt[i]);
2374 log_write(0, LOG_MAIN, "%s", big_buffer);
2376 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2378 log_write(0, LOG_MAIN|LOG_REJECT,
2379 "connection from %s refused (IP options)", host_and_ident(FALSE));
2381 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2385 /* Length of options = 0 => there are no options */
2387 else DEBUG(D_receive) debug_printf("no IP options found\n");
2389 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2391 /* Set keep-alive in socket options. The option is on by default. This
2392 setting is an attempt to get rid of some hanging connections that stick in
2393 read() when the remote end (usually a dialup) goes away. */
2395 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2396 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2398 /* If the current host matches host_lookup, set the name by doing a
2399 reverse lookup. On failure, sender_host_name will be NULL and
2400 host_lookup_failed will be TRUE. This may or may not be serious - optional
2403 if (verify_check_host(&host_lookup) == OK)
2405 (void)host_name_lookup();
2406 host_build_sender_fullhost();
2409 /* Delay this until we have the full name, if it is looked up. */
2411 set_process_info("handling incoming connection from %s",
2412 host_and_ident(FALSE));
2414 /* Expand smtp_receive_timeout, if needed */
2416 if (smtp_receive_timeout_s)
2419 if ( !(exp = expand_string(smtp_receive_timeout_s))
2421 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2423 log_write(0, LOG_MAIN|LOG_PANIC,
2424 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2427 /* Test for explicit connection rejection */
2429 if (verify_check_host(&host_reject_connection) == OK)
2431 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2432 "from %s (host_reject_connection)", host_and_ident(FALSE));
2434 if (!tls_in.on_connect)
2436 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2440 /* Test with TCP Wrappers if so configured. There is a problem in that
2441 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2442 such as disks dying. In these cases, it is desirable to reject with a 4xx
2443 error instead of a 5xx error. There isn't a "right" way to detect such
2444 problems. The following kludge is used: errno is zeroed before calling
2445 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2446 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2449 #ifdef USE_TCP_WRAPPERS
2451 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2452 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2453 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2454 expand_string_message);
2456 if (!hosts_ctl(tcp_wrappers_name,
2457 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2458 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2459 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2461 if (errno == 0 || errno == ENOENT)
2463 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2464 log_write(L_connection_reject,
2465 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2466 "(tcp wrappers)", host_and_ident(FALSE));
2467 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2471 int save_errno = errno;
2472 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2473 "errno value %d\n", save_errno);
2474 log_write(L_connection_reject,
2475 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2476 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2477 smtp_printf("451 Temporary local problem - please try later\r\n", SP_NO_MORE);
2483 /* Check for reserved slots. The value of smtp_accept_count has already been
2484 incremented to include this process. */
2486 if (smtp_accept_max > 0 &&
2487 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2489 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2491 log_write(L_connection_reject,
2492 LOG_MAIN, "temporarily refused connection from %s: not in "
2493 "reserve list: connected=%d max=%d reserve=%d%s",
2494 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2495 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2496 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2497 "please try again later\r\n", SP_NO_MORE, smtp_active_hostname);
2500 reserved_host = TRUE;
2503 /* If a load level above which only messages from reserved hosts are
2504 accepted is set, check the load. For incoming calls via the daemon, the
2505 check is done in the superior process if there are no reserved hosts, to
2506 save a fork. In all cases, the load average will already be available
2507 in a global variable at this point. */
2509 if (smtp_load_reserve >= 0 &&
2510 load_average > smtp_load_reserve &&
2512 verify_check_host(&smtp_reserve_hosts) != OK)
2514 log_write(L_connection_reject,
2515 LOG_MAIN, "temporarily refused connection from %s: not in "
2516 "reserve list and load average = %.2f", host_and_ident(FALSE),
2517 (double)load_average/1000.0);
2518 smtp_printf("421 %s: Too much load; please try again later\r\n", SP_NO_MORE,
2519 smtp_active_hostname);
2523 /* Determine whether unqualified senders or recipients are permitted
2524 for this host. Unfortunately, we have to do this every time, in order to
2525 set the flags so that they can be inspected when considering qualifying
2526 addresses in the headers. For a site that permits no qualification, this
2527 won't take long, however. */
2529 f.allow_unqualified_sender =
2530 verify_check_host(&sender_unqualified_hosts) == OK;
2532 f.allow_unqualified_recipient =
2533 verify_check_host(&recipient_unqualified_hosts) == OK;
2535 /* Determine whether HELO/EHLO is required for this host. The requirement
2536 can be hard or soft. */
2538 fl.helo_verify_required = verify_check_host(&helo_verify_hosts) == OK;
2539 if (!fl.helo_verify_required)
2540 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2542 /* Determine whether this hosts is permitted to send syntactic junk
2543 after a HELO or EHLO command. */
2545 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2548 /* Expand recipients_max, if needed */
2550 uschar * rme = expand_string(recipients_max);
2551 recipients_max_expanded = atoi(CCS rme);
2553 /* For batch SMTP input we are now done. */
2555 if (smtp_batched_input) return TRUE;
2557 #if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS) || defined(EXPERIMENTAL_XCLIENT)
2558 proxy_session = FALSE;
2561 #ifdef SUPPORT_PROXY
2562 /* If valid Proxy Protocol source is connecting, set up session.
2563 Failure will not allow any SMTP function other than QUIT. */
2565 f.proxy_session_failed = FALSE;
2566 if (proxy_protocol_host())
2568 os_non_restarting_signal(SIGALRM, command_timeout_handler);
2569 proxy_protocol_setup();
2573 /* Run the connect ACL if it exists */
2576 GET_OPTION("acl_smtp_connect");
2577 if (acl_smtp_connect)
2580 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2584 if (tls_in.on_connect)
2585 log_connect_tls_drop(US"'connect' ACL", log_msg);
2588 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2593 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2594 smtps port for use with older style SSL MTAs. */
2597 if (tls_in.on_connect)
2599 if (tls_server_start(&user_msg) != OK)
2600 return smtp_log_tls_fail(user_msg);
2601 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
2605 /* Output the initial message for a two-way SMTP connection. It may contain
2606 newlines, which then cause a multi-line response to be given. */
2608 code = US"220"; /* Default status code */
2609 esc = US""; /* Default extended status code */
2610 esclen = 0; /* Length of esc */
2616 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2620 esclen = codelen - 4;
2625 GET_OPTION("smtp_banner");
2626 if (!(s = expand_string(smtp_banner)))
2628 log_write(0, f.expand_string_forcedfail ? LOG_MAIN : LOG_MAIN|LOG_PANIC_DIE,
2629 "Expansion of \"%s\" (smtp_banner) failed: %s",
2630 smtp_banner, expand_string_message);
2631 /* for force-fail */
2633 if (tls_in.on_connect) tls_close(NULL, TLS_SHUTDOWN_WAIT);
2639 /* Remove any terminating newlines; might as well remove trailing space too */
2642 while (p > s && isspace(p[-1])) p--;
2643 s = string_copyn(s, p-s);
2645 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2646 is all contained in a single IP packet. The original code wrote out the
2647 greeting using several calls to fprint/fputc, and on busy servers this could
2648 cause it to be split over more than one packet - which caused CC:Mail to fall
2649 over when it got the second part of the greeting after sending its first
2650 command. Sigh. To try to avoid this, build the complete greeting message
2651 first, and output it in one fell swoop. This gives a better chance of it
2652 ending up as a single packet. */
2654 ss = string_get(256);
2657 do /* At least once, in case we have an empty string */
2660 uschar *linebreak = Ustrchr(p, '\n');
2661 ss = string_catn(ss, code, 3);
2665 ss = string_catn(ss, US" ", 1);
2669 len = linebreak - p;
2670 ss = string_catn(ss, US"-", 1);
2672 ss = string_catn(ss, esc, esclen);
2673 ss = string_catn(ss, p, len);
2674 ss = string_catn(ss, US"\r\n", 2);
2680 /* Before we write the banner, check that there is no input pending, unless
2681 this synchronisation check is disabled. */
2683 #ifndef DISABLE_PIPE_CONNECT
2684 fl.pipe_connect_acceptable =
2685 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
2688 if (fl.pipe_connect_acceptable)
2689 f.smtp_in_early_pipe_used = TRUE;
2695 unsigned n = smtp_inend - smtp_inptr;
2696 if (n > 128) n = 128;
2698 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2699 "synchronization error (input sent without waiting for greeting): "
2700 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2701 string_printing(string_copyn(smtp_inptr, n)));
2702 smtp_printf("554 SMTP synchronization error\r\n", SP_NO_MORE);
2706 /* Now output the banner */
2707 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
2710 #ifndef DISABLE_PIPE_CONNECT
2711 fl.pipe_connect_acceptable && pipeline_connect_sends(),
2717 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2718 handshake arrived. If so we must have managed a TFO. */
2721 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
2731 /*************************************************
2732 * Handle SMTP syntax and protocol errors *
2733 *************************************************/
2735 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2736 to do so. Then transmit the error response. The return value depends on the
2737 number of syntax and protocol errors in this SMTP session.
2740 type error type, given as a log flag bit
2741 code response code; <= 0 means don't send a response
2742 data data to reflect in the response (can be NULL)
2743 errmess the error message
2745 Returns: -1 limit of syntax/protocol errors NOT exceeded
2746 +1 limit of syntax/protocol errors IS exceeded
2748 These values fit in with the values of the "done" variable in the main
2749 processing loop in smtp_setup_msg(). */
2752 synprot_error(int type, int code, uschar *data, uschar *errmess)
2756 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2757 type == L_smtp_syntax_error ? "syntax" : "protocol",
2758 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2760 if (++synprot_error_count > smtp_max_synprot_errors)
2763 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2764 "syntax or protocol errors (last command was \"%s\", %Y)",
2765 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
2772 smtp_printf("%d%c%s%s%s\r\n", SP_NO_MORE, code, yield == 1 ? '-' : ' ',
2773 data ? data : US"", data ? US": " : US"", errmess);
2775 smtp_printf("%d Too many syntax or protocol errors\r\n", SP_NO_MORE, code);
2784 /*************************************************
2785 * Send SMTP response, possibly multiline *
2786 *************************************************/
2788 /* There are, it seems, broken clients out there that cannot handle multiline
2789 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2790 output nothing for non-final calls, and only the first line for anything else.
2793 code SMTP code, may involve extended status codes
2794 codelen length of smtp code; if > 4 there's an ESC
2795 final FALSE if the last line isn't the final line
2796 msg message text, possibly containing newlines
2802 smtp_respond(uschar * code, int codelen, BOOL final, uschar * msg)
2807 if (!final && f.no_multiline_responses) return;
2812 esclen = codelen - 4;
2815 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2816 have had the same. Note: this code is also present in smtp_printf(). It would
2817 be tidier to have it only in one place, but when it was added, it was easier to
2818 do it that way, so as not to have to mess with the code for the RCPT command,
2819 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2821 if (fl.rcpt_in_progress)
2823 if (!rcpt_smtp_response)
2824 rcpt_smtp_response = string_copy(msg);
2825 else if (fl.rcpt_smtp_response_same &&
2826 Ustrcmp(rcpt_smtp_response, msg) != 0)
2827 fl.rcpt_smtp_response_same = FALSE;
2828 fl.rcpt_in_progress = FALSE;
2831 /* Now output the message, splitting it up into multiple lines if necessary.
2832 We only handle pipelining these responses as far as nonfinal/final groups,
2833 not the whole MAIL/RCPT/DATA response set. */
2837 uschar *nl = Ustrchr(msg, '\n');
2840 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
2843 else if (nl[1] == 0 || f.no_multiline_responses)
2845 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
2846 (int)(nl - msg), msg);
2851 smtp_printf("%.3s-%.*s%.*s\r\n", SP_MORE, code, esclen, esc, (int)(nl - msg), msg);
2853 Uskip_whitespace(&msg);
2861 /*************************************************
2862 * Parse user SMTP message *
2863 *************************************************/
2865 /* This function allows for user messages overriding the response code details
2866 by providing a suitable response code string at the start of the message
2867 user_msg. Check the message for starting with a response code and optionally an
2868 extended status code. If found, check that the first digit is valid, and if so,
2869 change the code pointer and length to use the replacement. An invalid code
2870 causes a panic log; in this case, if the log messages is the same as the user
2871 message, we must also adjust the value of the log message to show the code that
2872 is actually going to be used (the original one).
2874 This function is global because it is called from receive.c as well as within
2877 Note that the code length returned includes the terminating whitespace
2878 character, which is always included in the regex match.
2881 code SMTP code, may involve extended status codes
2882 codelen length of smtp code; if > 4 there's an ESC
2884 log_msg optional log message, to be adjusted with the new SMTP code
2885 check_valid if true, verify the response code
2891 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2897 if (!msg || !*msg || !regex_match(regex_smtp_code, *msg, -1, &match))
2900 len = Ustrlen(match);
2901 if (check_valid && (*msg)[0] != (*code)[0])
2903 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2904 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2905 if (log_msg && *log_msg == *msg)
2906 *log_msg = string_sprintf("%s %s", *code, *log_msg + len);
2911 *codelen = len; /* Includes final space */
2913 *msg += len; /* Chop the code off the message */
2920 /*************************************************
2921 * Handle an ACL failure *
2922 *************************************************/
2924 /* This function is called when acl_check() fails. As well as calls from within
2925 this module, it is called from receive.c for an ACL after DATA. It sorts out
2926 logging the incident, and sends the error response. A message containing
2927 newlines is turned into a multiline SMTP response, but for logging, only the
2930 There's a table of default permanent failure response codes to use in
2931 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2932 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2933 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2934 state, because there are broken clients that try VRFY before RCPT. A 5xx
2935 response should be given only when the address is positively known to be
2936 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2937 no explicit code, but if there is one we let it know best.
2938 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2940 From Exim 4.63, it is possible to override the response code details by
2941 providing a suitable response code string at the start of the message provided
2942 in user_msg. The code's first digit is checked for validity.
2945 where where the ACL was called from
2947 user_msg a message that can be included in an SMTP response
2948 log_msg a message for logging
2950 Returns: 0 in most cases
2951 2 if the failure code was FAIL_DROP, in which case the
2952 SMTP connection should be dropped (this value fits with the
2953 "done" variable in smtp_setup_msg() below)
2957 smtp_handle_acl_fail(int where, int rc, uschar * user_msg, uschar * log_msg)
2959 BOOL drop = rc == FAIL_DROP;
2963 uschar *sender_info = US"";
2966 if (drop) rc = FAIL;
2968 /* Set the default SMTP code, and allow a user message to change it. */
2970 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2971 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2972 where != ACL_WHERE_VRFY);
2974 /* We used to have sender_address here; however, there was a bug that was not
2975 updating sender_address after a rewrite during a verify. When this bug was
2976 fixed, sender_address at this point became the rewritten address. I'm not sure
2977 this is what should be logged, so I've changed to logging the unrewritten
2978 address to retain backward compatibility. */
2982 #ifdef WITH_CONTENT_SCAN
2983 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
2985 case ACL_WHERE_PREDATA: what = US"DATA"; break;
2986 case ACL_WHERE_DATA: what = US"after DATA"; break;
2987 #ifndef DISABLE_PRDR
2988 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
2992 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
2995 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
2997 uschar * s = smtp_cmd_data;
2999 lim = s - smtp_cmd_data; /* atop after method */
3001 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
3006 case ACL_WHERE_RCPT:
3007 case ACL_WHERE_DATA:
3008 #ifdef WITH_CONTENT_SCAN
3009 case ACL_WHERE_MIME:
3011 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3012 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3013 sender_host_authenticated ? US" A=" : US"",
3014 sender_host_authenticated ? sender_host_authenticated : US"",
3015 sender_host_authenticated && authenticated_id ? US":" : US"",
3016 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3021 /* If there's been a sender verification failure with a specific message, and
3022 we have not sent a response about it yet, do so now, as a preliminary line for
3023 failures, but not defers. However, always log it for defer, and log it for fail
3024 unless the sender_verify_fail log selector has been turned off. */
3026 if (sender_verified_failed &&
3027 !testflag(sender_verified_failed, af_sverify_told))
3029 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3030 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3032 setflag(sender_verified_failed, af_sverify_told);
3034 if (rc != FAIL || LOGGING(sender_verify_fail))
3035 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3036 host_and_ident(TRUE),
3037 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3038 sender_verified_failed->address,
3039 (sender_verified_failed->message == NULL)? US"" :
3040 string_sprintf(": %s", sender_verified_failed->message));
3042 if (rc == FAIL && sender_verified_failed->user_message)
3043 smtp_respond(smtp_code, codelen, SR_NOT_FINAL, string_sprintf(
3044 testflag(sender_verified_failed, af_verify_pmfail)?
3045 "Postmaster verification failed while checking <%s>\n%s\n"
3046 "Several RFCs state that you are required to have a postmaster\n"
3047 "mailbox for each mail domain. This host does not accept mail\n"
3048 "from domains whose servers reject the postmaster address."
3050 testflag(sender_verified_failed, af_verify_nsfail)?
3051 "Callback setup failed while verifying <%s>\n%s\n"
3052 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3053 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3054 "RFC requirements, and stops you from receiving standard bounce\n"
3055 "messages. This host does not accept mail from domains whose servers\n"
3058 "Verification failed for <%s>\n%s",
3059 sender_verified_failed->address,
3060 sender_verified_failed->user_message));
3062 fl.rcpt_in_progress = save_rcpt_in_progress;
3065 /* Sort out text for logging */
3067 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3068 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3070 /* Send permanent failure response to the command, but the code used isn't
3071 always a 5xx one - see comments at the start of this function. If the original
3072 rc was FAIL_DROP we drop the connection and yield 2. */
3075 smtp_respond(smtp_code, codelen, SR_FINAL,
3076 user_msg ? user_msg : US"Administrative prohibition");
3078 /* Send temporary failure response to the command. Don't give any details,
3079 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3080 verb, and for a header verify when smtp_return_error_details is set.
3082 This conditional logic is all somewhat of a mess because of the odd
3083 interactions between temp_details and return_error_details. One day it should
3084 be re-implemented in a tidier fashion. */
3087 if (f.acl_temp_details && user_msg)
3089 if ( smtp_return_error_details
3090 && sender_verified_failed
3091 && sender_verified_failed->message
3093 smtp_respond(smtp_code, codelen, SR_NOT_FINAL, sender_verified_failed->message);
3095 smtp_respond(smtp_code, codelen, SR_FINAL, user_msg);
3098 smtp_respond(smtp_code, codelen, SR_FINAL,
3099 US"Temporary local problem - please try later");
3101 /* Log the incident to the logs that are specified by log_reject_target
3102 (default main, reject). This can be empty to suppress logging of rejections. If
3103 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3104 is closing if required and return 2. */
3106 if (log_reject_target)
3109 gstring * g = s_tlslog(NULL);
3110 uschar * tls = string_from_gstring(g);
3111 if (!tls) tls = US"";
3113 uschar * tls = US"";
3115 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3116 log_reject_target, "%s%s%s %s%srejected %s%s",
3117 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3118 host_and_ident(TRUE),
3121 rc == FAIL ? US"" : US"temporarily ",
3125 if (!drop) return 0;
3127 log_close_event(US"by DROP in ACL");
3129 /* Run the not-quit ACL, but without any custom messages. This should not be a
3130 problem, because we get here only if some other ACL has issued "drop", and
3131 in that case, *its* custom messages will have been used above. */
3133 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3135 /* An overenthusiastic fail2ban/iptables implimentation has been seen to result
3136 in the TCP conn staying open, and retrying, despite this process exiting. A
3137 malicious client could possibly do the same, tying up server netowrking
3138 resources. Close the socket explicitly to try to avoid that (there's a note in
3139 the Linux socket(7) manpage, SO_LINGER para, to the effect that exim() without
3140 close() results in the socket always lingering). */
3142 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3143 DEBUG(D_any) debug_printf_indent("SMTP(close)>>\n");
3144 (void) fclose(smtp_in);
3145 (void) fclose(smtp_out);
3153 /*************************************************
3154 * Handle SMTP exit when QUIT is not given *
3155 *************************************************/
3157 /* This function provides a logging/statistics hook for when an SMTP connection
3158 is dropped on the floor or the other end goes away. It's a global function
3159 because it's called from receive.c as well as this module. As well as running
3160 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3161 response, either with a custom message from the ACL, or using a default. There
3162 is one case, however, when no message is output - after "drop". In that case,
3163 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3164 passed to this function.
3166 In case things go wrong while processing this function, causing an error that
3167 may re-enter this function, there is a recursion check.
3170 reason What $smtp_notquit_reason will be set to in the ACL;
3171 if NULL, the ACL is not run
3172 code The error code to return as part of the response
3173 defaultrespond The default message if there's no user_msg
3179 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3182 uschar *user_msg = NULL;
3183 uschar *log_msg = NULL;
3185 /* Check for recursive call */
3187 if (fl.smtp_exit_function_called)
3189 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3193 fl.smtp_exit_function_called = TRUE;
3195 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3197 GET_OPTION("acl_smtp_notquit");
3198 if (acl_smtp_notquit && reason)
3200 smtp_notquit_reason = reason;
3201 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3202 &log_msg)) == ERROR)
3203 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3207 /* If the connection was dropped, we certainly are no longer talking TLS */
3208 tls_in.active.sock = -1;
3210 /* Write an SMTP response if we are expected to give one. As the default
3211 responses are all internal, they should be reasonable size. */
3213 if (code && defaultrespond)
3216 smtp_respond(code, 3, SR_FINAL, user_msg);
3222 va_start(ap, defaultrespond);
3223 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3225 smtp_printf("%s %Y\r\n", SP_NO_MORE, code, g);
3234 /*************************************************
3235 * Verify HELO argument *
3236 *************************************************/
3238 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3239 matched. It is also called from ACL processing if verify = helo is used and
3240 verification was not previously tried (i.e. helo_try_verify_hosts was not
3241 matched). The result of its processing is to set helo_verified and
3242 helo_verify_failed. These variables should both be FALSE for this function to
3245 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3246 for IPv6 ::ffff: literals.
3249 Returns: TRUE if testing was completed;
3250 FALSE on a temporary failure
3254 smtp_verify_helo(void)
3258 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3261 if (sender_helo_name == NULL)
3263 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3266 /* Deal with the case of -bs without an IP address */
3268 else if (sender_host_address == NULL)
3270 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3271 f.helo_verified = TRUE;
3274 /* Deal with the more common case when there is a sending IP address */
3276 else if (sender_helo_name[0] == '[')
3278 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3279 Ustrlen(sender_host_address)) == 0;
3282 if (!f.helo_verified)
3284 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3285 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3286 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3291 { if (f.helo_verified) debug_printf("matched host address\n"); }
3294 /* Do a reverse lookup if one hasn't already given a positive or negative
3295 response. If that fails, or the name doesn't match, try checking with a forward
3300 if (sender_host_name == NULL && !host_lookup_failed)
3301 yield = host_name_lookup() != DEFER;
3303 /* If a host name is known, check it and all its aliases. */
3305 if (sender_host_name)
3306 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3308 sender_helo_dnssec = sender_host_dnssec;
3309 HDEBUG(D_receive) debug_printf("matched host name\n");
3313 uschar **aliases = sender_host_aliases;
3315 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3317 sender_helo_dnssec = sender_host_dnssec;
3321 HDEBUG(D_receive) if (f.helo_verified)
3322 debug_printf("matched alias %s\n", *(--aliases));
3325 /* Final attempt: try a forward lookup of the helo name */
3327 if (!f.helo_verified)
3331 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3333 {.request = US"*", .require = US""};
3335 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3337 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3338 NULL, NULL, NULL, &d, NULL, NULL);
3339 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3340 for (host_item * hh = &h; hh; hh = hh->next)
3341 if (Ustrcmp(hh->address, sender_host_address) == 0)
3343 f.helo_verified = TRUE;
3344 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3346 debug_printf("IP address for %s matches calling address\n"
3347 "Forward DNS security status: %sverified\n",
3348 sender_helo_name, sender_helo_dnssec ? "" : "un");
3354 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3361 /*************************************************
3362 * Send user response message *
3363 *************************************************/
3365 /* This function is passed a default response code and a user message. It calls
3366 smtp_message_code() to check and possibly modify the response code, and then
3367 calls smtp_respond() to transmit the response. I put this into a function
3368 just to avoid a lot of repetition.
3371 code the response code
3372 user_msg the user message
3378 smtp_user_msg(uschar *code, uschar *user_msg)
3381 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3382 smtp_respond(code, len, SR_FINAL, user_msg);
3388 smtp_in_auth(auth_instance *au, uschar ** smtp_resp, uschar ** errmsg)
3390 const uschar *set_id = NULL;
3393 /* Set up globals for error messages */
3395 authenticator_name = au->name;
3396 driver_srcfile = au->srcfile;
3397 driver_srcline = au->srcline;
3399 /* Run the checking code, passing the remainder of the command line as
3400 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3401 it as the only set numerical variable. The authenticator may set $auth<n>
3402 and also set other numeric variables. The $auth<n> variables are preferred
3403 nowadays; the numerical variables remain for backwards compatibility.
3405 Afterwards, have a go at expanding the set_id string, even if
3406 authentication failed - for bad passwords it can be useful to log the
3407 userid. On success, require set_id to expand and exist, and put it in
3408 authenticated_id. Save this in permanent store, as the working store gets
3409 reset at HELO, RSET, etc. */
3411 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3413 expand_nlength[0] = 0; /* $0 contains nothing */
3415 rc = (au->info->servercode)(au, smtp_cmd_data);
3416 if (au->set_id) set_id = expand_string(au->set_id);
3417 expand_nmax = -1; /* Reset numeric variables */
3418 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3419 driver_srcfile = authenticator_name = NULL; driver_srcline = 0;
3421 /* The value of authenticated_id is stored in the spool file and printed in
3422 log lines. It must not contain binary zeros or newline characters. In
3423 normal use, it never will, but when playing around or testing, this error
3424 can (did) happen. To guard against this, ensure that the id contains only
3425 printing characters. */
3427 if (set_id) set_id = string_printing(set_id);
3429 /* For the non-OK cases, set up additional logging data if set_id
3433 set_id = set_id && *set_id
3434 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3436 /* Switch on the result */
3441 if (!au->set_id || set_id) /* Complete success */
3443 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3444 sender_host_authenticated = au->name;
3445 sender_host_auth_pubname = au->public_name;
3446 authentication_failed = FALSE;
3447 authenticated_fail_id = NULL; /* Impossible to already be set? */
3450 (sender_host_address ? protocols : protocols_local)
3451 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3452 *smtp_resp = *errmsg = US"235 Authentication succeeded";
3453 authenticated_by = au;
3457 /* Authentication succeeded, but we failed to expand the set_id string.
3458 Treat this as a temporary error. */
3460 auth_defer_msg = expand_string_message;
3464 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3465 *smtp_resp = string_sprintf("435 Unable to authenticate at present%s",
3466 auth_defer_user_msg);
3467 *errmsg = string_sprintf("435 Unable to authenticate at present%s: %s",
3468 set_id, auth_defer_msg);
3472 *smtp_resp = *errmsg = US"501 Invalid base64 data";
3476 *smtp_resp = *errmsg = US"501 Authentication cancelled";
3480 *smtp_resp = *errmsg = US"553 Initial data not expected";
3484 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3485 *smtp_resp = US"535 Incorrect authentication data";
3486 *errmsg = string_sprintf("535 Incorrect authentication data%s", set_id);
3490 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3491 *smtp_resp = US"435 Internal error";
3492 *errmsg = string_sprintf("435 Internal error%s: return %d from authentication "
3493 "check", set_id, rc);
3505 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3508 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3510 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3512 rd = Ustrlen(recipient) + 1;
3513 /* deconst ok as *recipient was not const */
3514 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3517 smtp_printf("501 %s: recipient address must contain a domain\r\n", SP_NO_MORE,
3519 log_write(L_smtp_syntax_error,
3520 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3521 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3529 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3532 f.smtp_in_quit = TRUE;
3533 incomplete_transaction_log(US"QUIT");
3534 GET_OPTION("acl_smtp_quit");
3536 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3538 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3541 #ifdef EXIM_TCP_CORK
3542 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
3546 smtp_respond(US"221", 3, SR_FINAL, *user_msgp);
3548 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
3550 #ifdef SERVERSIDE_CLOSE_NOWAIT
3551 # ifndef DISABLE_TLS
3552 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3555 log_close_event(US"by QUIT");
3558 # ifndef DISABLE_TLS
3559 tls_close(NULL, TLS_SHUTDOWN_WAIT);
3562 log_close_event(US"by QUIT");
3564 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
3565 The socket should become readble (though with no data) */
3567 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3568 #endif /*!SERVERSIDE_CLOSE_NOWAIT*/
3573 smtp_rset_handler(void)
3576 incomplete_transaction_log(US"RSET");
3577 smtp_printf("250 Reset OK\r\n", SP_NO_MORE);
3578 cmd_list[CL_RSET].is_mail_cmd = FALSE;
3579 if (chunking_state > CHUNKING_OFFERED)
3580 chunking_state = CHUNKING_OFFERED;
3585 expand_mailmax(const uschar * s)
3587 if (!(s = expand_cstring(s)))
3588 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
3589 return *s ? Uatoi(s) : 0;
3592 /*************************************************
3593 * Initialize for SMTP incoming message *
3594 *************************************************/
3596 /* This function conducts the initial dialogue at the start of an incoming SMTP
3597 message, and builds a list of recipients. However, if the incoming message
3598 is part of a batch (-bS option) a separate function is called since it would
3599 be messy having tests splattered about all over this function. This function
3600 therefore handles the case where interaction is occurring. The input and output
3601 files are set up in smtp_in and smtp_out.
3603 The global recipients_list is set to point to a vector of recipient_item
3604 blocks, whose number is given by recipients_count. This is extended by the
3605 receive_add_recipient() function. The global variable sender_address is set to
3606 the sender's address. The yield is +1 if a message has been successfully
3607 started, 0 if a QUIT command was encountered or the connection was refused from
3608 the particular host, or -1 if the connection was lost.
3612 Returns: > 0 message successfully started (reached DATA)
3613 = 0 QUIT read or end of file reached or call refused
3618 smtp_setup_msg(void)
3621 BOOL toomany = FALSE;
3622 BOOL discarded = FALSE;
3623 BOOL last_was_rej_mail = FALSE;
3624 BOOL last_was_rcpt = FALSE;
3625 rmark reset_point = store_mark();
3627 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3629 /* Reset for start of new message. We allow one RSET not to be counted as a
3630 nonmail command, for those MTAs that insist on sending it between every
3631 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3632 TLS between messages (an Exim client may do this if it has messages queued up
3633 for the host). Note: we do NOT reset AUTH at this point. */
3635 reset_point = smtp_reset(reset_point);
3636 message_ended = END_NOTSTARTED;
3638 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3640 cmd_list[CL_RSET].is_mail_cmd = TRUE;
3641 cmd_list[CL_HELO].is_mail_cmd = TRUE;
3642 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
3644 cmd_list[CL_STLS].is_mail_cmd = TRUE;
3647 if (lwr_receive_getc != NULL)
3649 /* This should have already happened, but if we've gotten confused,
3650 force a reset here. */
3651 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
3652 bdat_pop_receive_functions();
3655 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3657 had_command_sigterm = 0;
3658 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3660 /* Batched SMTP is handled in a different function. */
3662 if (smtp_batched_input) return smtp_setup_batch_msg();
3665 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3666 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3667 US &off, sizeof(off));
3670 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3671 value. The values are 2 larger than the required yield of the function. */
3675 const uschar **argv;
3676 uschar *etrn_command;
3677 uschar *etrn_serialize_key;
3679 uschar *log_msg, *smtp_code;
3680 uschar *user_msg = NULL;
3681 uschar *recipient = NULL;
3682 uschar *hello = NULL;
3684 BOOL was_rej_mail = FALSE;
3685 BOOL was_rcpt = FALSE;
3686 void (*oldsignal)(int);
3688 int start, end, sender_domain, recipient_domain;
3691 uschar *orcpt = NULL;
3696 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3697 if ( tls_in.active.sock >= 0
3699 && tls_in.certificate_verified
3700 && cmd_list[CL_TLAU].is_mail_cmd
3703 cmd_list[CL_TLAU].is_mail_cmd = FALSE;
3705 for (auth_instance * au = auths; au; au = au->next)
3706 if (strcmpic(US"tls", au->driver_name) == 0)
3708 GET_OPTION("acl_smtp_auth");
3710 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3711 &user_msg, &log_msg)) != OK
3713 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3716 smtp_cmd_data = NULL;
3718 if (smtp_in_auth(au, &s, &ss) == OK)
3719 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3722 DEBUG(D_auth) debug_printf("tls auth not succeeded\n");
3723 #ifndef DISABLE_EVENT
3725 uschar * save_name = sender_host_authenticated, * logmsg;
3726 sender_host_authenticated = au->name;
3727 if ((logmsg = event_raise(event_action, US"auth:fail", s, NULL)))
3728 log_write(0, LOG_MAIN, "%s", logmsg);
3729 sender_host_authenticated = save_name;
3739 switch(smtp_read_command(
3740 #ifndef DISABLE_PIPE_CONNECT
3741 !fl.pipe_connect_acceptable,
3745 GETC_BUFFER_UNLIMITED))
3747 /* The AUTH command is not permitted to occur inside a transaction, and may
3748 occur successfully only once per connection. Actually, that isn't quite
3749 true. When TLS is started, all previous information about a connection must
3750 be discarded, so a new AUTH is permitted at that time.
3752 AUTH may only be used when it has been advertised. However, it seems that
3753 there are clients that send AUTH when it hasn't been advertised, some of
3754 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3755 So there's a get-out that allows this to happen.
3757 AUTH is initially labelled as a "nonmail command" so that one occurrence
3758 doesn't get counted. We change the label here so that multiple failing
3759 AUTHS will eventually hit the nonmail threshold. */
3763 authentication_failed = TRUE;
3764 cmd_list[CL_AUTH].is_mail_cmd = FALSE;
3766 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
3768 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3769 US"AUTH command used when not advertised");
3772 if (sender_host_authenticated)
3774 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3775 US"already authenticated");
3780 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3781 US"not permitted in mail transaction");
3787 GET_OPTION("acl_smtp_auth");
3789 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3790 &user_msg, &log_msg)) != OK
3793 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3797 /* Find the name of the requested authentication mechanism. */
3800 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
3801 if (!isalnum(c) && c != '-' && c != '_')
3803 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3804 US"invalid character in authentication mechanism name");
3808 /* If not at the end of the line, we must be at white space. Terminate the
3809 name and move the pointer on to any data that may be present. */
3813 *smtp_cmd_data++ = '\0';
3814 Uskip_whitespace(&smtp_cmd_data);
3817 /* Search for an authentication mechanism which is configured for use
3818 as a server and which has been advertised (unless, sigh, allow_auth_
3819 unadvertised is set). */
3823 uschar * smtp_resp, * errmsg;
3825 for (au = auths; au; au = au->next)
3826 if (strcmpic(s, au->public_name) == 0 && au->server &&
3827 (au->advertised || f.allow_auth_unadvertised))
3832 int rc = smtp_in_auth(au, &smtp_resp, &errmsg);
3834 smtp_printf("%s\r\n", SP_NO_MORE, smtp_resp);
3837 uschar * logmsg = NULL;
3838 #ifndef DISABLE_EVENT
3839 {uschar * save_name = sender_host_authenticated;
3840 sender_host_authenticated = au->name;
3841 logmsg = event_raise(event_action, US"auth:fail", smtp_resp, NULL);
3842 sender_host_authenticated = save_name;
3846 log_write(0, LOG_MAIN|LOG_REJECT, "%s", logmsg);
3848 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3849 au->name, host_and_ident(FALSE), errmsg);
3853 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3854 string_sprintf("%s authentication mechanism not supported", s));
3857 break; /* AUTH_CMD */
3859 /* The HELO/EHLO commands are permitted to appear in the middle of a
3860 session as well as at the beginning. They have the effect of a reset in
3861 addition to their other functions. Their absence at the start cannot be
3862 taken to be an error.
3866 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3867 or 502 failure replies MUST be returned as appropriate. The SMTP
3868 server MUST stay in the same state after transmitting these replies
3869 that it was in before the EHLO was received.
3871 Therefore, we do not do the reset until after checking the command for
3872 acceptability. This change was made for Exim release 4.11. Previously
3873 it did the reset first. */
3886 HELO_EHLO: /* Common code for HELO and EHLO */
3887 cmd_list[CL_HELO].is_mail_cmd = FALSE;
3888 cmd_list[CL_EHLO].is_mail_cmd = FALSE;
3890 /* Reject the HELO if its argument was invalid or non-existent. A
3891 successful check causes the argument to be saved in malloc store. */
3893 if (!check_helo(smtp_cmd_data))
3895 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", SP_NO_MORE, hello);
3897 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3898 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3899 *smtp_cmd_argument == 0 ? US"(no argument given)" :
3900 string_printing(smtp_cmd_argument));
3902 if (++synprot_error_count > smtp_max_synprot_errors)
3904 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3905 "syntax or protocol errors (last command was \"%s\", %Y)",
3906 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3915 /* If sender_host_unknown is true, we have got here via the -bs interface,
3916 not called from inetd. Otherwise, we are running an IP connection and the
3917 host address will be set. If the helo name is the primary name of this
3918 host and we haven't done a reverse lookup, force one now. If helo_verify_required
3919 is set, ensure that the HELO name matches the actual host. If helo_verify
3920 is set, do the same check, but softly. */
3922 if (!f.sender_host_unknown)
3924 BOOL old_helo_verified = f.helo_verified;
3925 uschar * p = smtp_cmd_data;
3927 while (*p && !isspace(*p)) { *p = tolower(*p); p++; }
3930 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3931 because otherwise the log can be confusing. */
3933 if ( !sender_host_name
3934 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3935 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
3936 (void)host_name_lookup();
3938 /* Rebuild the fullhost info to include the HELO name (and the real name
3939 if it was looked up.) */
3941 host_build_sender_fullhost(); /* Rebuild */
3942 set_process_info("handling%s incoming connection from %s",
3943 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
3945 /* Verify if configured. This doesn't give much security, but it does
3946 make some people happy to be able to do it. If helo_verify_required is set,
3947 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3948 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3949 now obsolescent, since the verification can now be requested selectively
3952 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
3953 if (fl.helo_verify_required || fl.helo_verify)
3955 BOOL tempfail = !smtp_verify_helo();
3956 if (!f.helo_verified)
3958 if (fl.helo_verify_required)
3960 smtp_printf("%d %s argument does not match calling host\r\n", SP_NO_MORE,
3961 tempfail? 451 : 550, hello);
3962 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3963 tempfail? "temporarily " : "",
3964 hello, sender_helo_name, host_and_ident(FALSE));
3965 f.helo_verified = old_helo_verified;
3966 break; /* End of HELO/EHLO processing */
3968 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3969 "helo_try_verify_hosts\n", hello);
3975 /* set up SPF context */
3976 spf_conn_init(sender_helo_name, sender_host_address);
3979 /* Apply an ACL check if one is defined; afterwards, recheck
3980 synchronization in case the client started sending in a delay. */
3982 GET_OPTION("acl_smtp_helo");
3984 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3985 &user_msg, &log_msg)) != OK)
3987 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3988 sender_helo_name = NULL;
3989 host_build_sender_fullhost(); /* Rebuild */
3992 #ifndef DISABLE_PIPE_CONNECT
3993 else if (!fl.pipe_connect_acceptable && !check_sync())
3995 else if (!check_sync())
3999 /* Generate an OK reply. The default string includes the ident if present,
4000 and also the IP address if present. Reflecting back the ident is intended
4001 as a deterrent to mail forgers. For maximum efficiency, and also because
4002 some broken systems expect each response to be in a single packet, arrange
4003 that the entire reply is sent in one write(). */
4005 fl.auth_advertised = FALSE;
4006 f.smtp_in_pipelining_advertised = FALSE;
4008 fl.tls_advertised = FALSE;
4010 fl.dsn_advertised = FALSE;
4012 fl.smtputf8_advertised = FALSE;
4015 /* Expand the per-connection message count limit option */
4016 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4018 smtp_code = US"250 "; /* Default response code plus space*/
4021 /* sender_host_name below will be tainted, so save on copy when we hit it */
4022 g = string_get_tainted(24, GET_TAINTED);
4023 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4025 smtp_active_hostname,
4026 sender_ident ? sender_ident : US"",
4027 sender_ident ? US" at " : US"",
4028 sender_host_name ? sender_host_name : sender_helo_name);
4030 if (sender_host_address)
4031 g = string_fmt_append(g, " [%s]", sender_host_address);
4034 /* A user-supplied EHLO greeting may not contain more than one line. Note
4035 that the code returned by smtp_message_code() includes the terminating
4036 whitespace character. */
4042 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4043 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4044 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4046 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4047 "newlines: message truncated: %s", string_printing(s));
4050 g = string_cat(NULL, s);
4053 g = string_catn(g, US"\r\n", 2);
4055 /* If we received EHLO, we must create a multiline response which includes
4056 the functions supported. */
4060 g->s[3] = '-'; /* overwrite the space after the SMTP response code */
4062 /* I'm not entirely happy with this, as an MTA is supposed to check
4063 that it has enough room to accept a message of maximum size before
4064 it sends this. However, there seems little point in not sending it.
4065 The actual size check happens later at MAIL FROM time. By postponing it
4066 till then, VRFY and EXPN can be used after EHLO when space is short. */
4068 if (thismessage_size_limit > 0)
4069 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4070 thismessage_size_limit);
4073 g = string_catn(g, smtp_code, 3);
4074 g = string_catn(g, US"-SIZE\r\n", 7);
4077 #ifndef DISABLE_ESMTP_LIMITS
4078 if ( (smtp_mailcmd_max > 0 || recipients_max_expanded > 0)
4079 && verify_check_host(&limits_advertise_hosts) == OK)
4081 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4082 if (smtp_mailcmd_max > 0)
4083 g = string_fmt_append(g, " MAILMAX=%d", smtp_mailcmd_max);
4084 if (recipients_max_expanded > 0)
4085 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max_expanded);
4086 g = string_catn(g, US"\r\n", 2);
4090 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4091 clean; if it has an 8-bit character in its hand, it just sends it. It
4092 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4093 However, some users want this option simply in order to stop MUAs
4094 mangling messages that contain top-bit-set characters. It is therefore
4095 provided as an option. */
4097 if (accept_8bitmime)
4099 g = string_catn(g, smtp_code, 3);
4100 g = string_catn(g, US"-8BITMIME\r\n", 11);
4103 /* Advertise DSN support if configured to do so. */
4104 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4106 g = string_catn(g, smtp_code, 3);
4107 g = string_catn(g, US"-DSN\r\n", 6);
4108 fl.dsn_advertised = TRUE;
4111 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4112 permitted to issue them; a check is made when any host actually tries. */
4114 GET_OPTION("acl_smtp_etrn");
4117 g = string_catn(g, smtp_code, 3);
4118 g = string_catn(g, US"-ETRN\r\n", 7);
4120 GET_OPTION("acl_smtp_vrfy");
4123 g = string_catn(g, smtp_code, 3);
4124 g = string_catn(g, US"-VRFY\r\n", 7);
4126 GET_OPTION("acl_smtp_expn");
4129 g = string_catn(g, smtp_code, 3);
4130 g = string_catn(g, US"-EXPN\r\n", 7);
4133 /* Exim is quite happy with pipelining, so let the other end know that
4134 it is safe to use it, unless advertising is disabled. */
4136 if ( f.pipelining_enable
4137 && verify_check_host(&pipelining_advertise_hosts) == OK)
4139 g = string_catn(g, smtp_code, 3);
4140 g = string_catn(g, US"-PIPELINING\r\n", 13);
4141 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4142 f.smtp_in_pipelining_advertised = TRUE;
4144 #ifndef DISABLE_PIPE_CONNECT
4145 if (fl.pipe_connect_acceptable)
4147 f.smtp_in_early_pipe_advertised = TRUE;
4148 g = string_catn(g, smtp_code, 3);
4149 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4155 /* If any server authentication mechanisms are configured, advertise
4156 them if the current host is in auth_advertise_hosts. The problem with
4157 advertising always is that some clients then require users to
4158 authenticate (and aren't configurable otherwise) even though it may not
4159 be necessary (e.g. if the host is in host_accept_relay).
4161 RFC 2222 states that SASL mechanism names contain only upper case
4162 letters, so output the names in upper case, though we actually recognize
4163 them in either case in the AUTH command. */
4167 && !sender_host_authenticated
4169 && verify_check_host(&auth_advertise_hosts) == OK
4173 for (auth_instance * au = auths; au; au = au->next)
4175 au->advertised = FALSE;
4178 DEBUG(D_auth+D_expand) debug_printf_indent(
4179 "Evaluating advertise_condition for %s %s athenticator\n",
4180 au->name, au->public_name);
4181 if ( !au->advertise_condition
4182 || expand_check_condition(au->advertise_condition, au->name,
4189 g = string_catn(g, smtp_code, 3);
4190 g = string_catn(g, US"-AUTH", 5);
4192 fl.auth_advertised = TRUE;
4194 saveptr = gstring_length(g);
4195 g = string_catn(g, US" ", 1);
4196 g = string_cat(g, au->public_name);
4197 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4198 au->advertised = TRUE;
4203 if (!first) g = string_catn(g, US"\r\n", 2);
4206 /* RFC 3030 CHUNKING */
4208 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4210 g = string_catn(g, smtp_code, 3);
4211 g = string_catn(g, US"-CHUNKING\r\n", 11);
4212 f.chunking_offered = TRUE;
4213 chunking_state = CHUNKING_OFFERED;
4216 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4217 if it has been included in the binary, and the host matches
4218 tls_advertise_hosts. We must *not* advertise if we are already in a
4219 secure connection. */
4222 if (tls_in.active.sock < 0 &&
4223 verify_check_host(&tls_advertise_hosts) != FAIL)
4225 g = string_catn(g, smtp_code, 3);
4226 g = string_catn(g, US"-STARTTLS\r\n", 11);
4227 fl.tls_advertised = TRUE;
4230 #ifdef EXPERIMENTAL_XCLIENT
4231 if (proxy_session || verify_check_host(&hosts_xclient) != FAIL)
4233 g = string_catn(g, smtp_code, 3);
4234 g = xclient_smtp_advertise_str(g);
4237 #ifndef DISABLE_PRDR
4238 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4241 g = string_catn(g, smtp_code, 3);
4242 g = string_catn(g, US"-PRDR\r\n", 7);
4247 if ( accept_8bitmime
4248 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4250 g = string_catn(g, smtp_code, 3);
4251 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4252 fl.smtputf8_advertised = TRUE;
4256 /* Finish off the multiline reply with one that is always available. */
4258 g = string_catn(g, smtp_code, 3);
4259 g = string_catn(g, US" HELP\r\n", 7);
4262 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4267 int len = len_string_from_gstring(g, &ehlo_resp);
4269 if (tls_in.active.sock >= 0)
4270 (void) tls_write(NULL, ehlo_resp, len,
4271 # ifndef DISABLE_PIPE_CONNECT
4272 fl.pipe_connect_acceptable && pipeline_connect_sends());
4278 (void) fwrite(ehlo_resp, 1, len, smtp_out);
4280 DEBUG(D_receive) for (const uschar * t, * s = ehlo_resp;
4281 s && (t = Ustrchr(s, '\r'));
4282 s = t + 2) /* \r\n */
4283 debug_printf("%s %.*s\n",
4284 s == g->s ? "SMTP>>" : " ",
4286 fl.helo_seen = TRUE;
4289 /* Reset the protocol and the state, abandoning any previous message. */
4291 (sender_host_address ? protocols : protocols_local)
4293 ? pextend + (sender_host_authenticated ? pauthed : 0)
4295 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4297 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4298 reset_point = smtp_reset(reset_point);
4300 break; /* HELO/EHLO */
4302 #ifdef EXPERIMENTAL_XCLIENT
4305 BOOL fatal = fl.helo_seen;
4310 smtp_mailcmd_count++;
4312 if ((errmsg = xclient_smtp_command(smtp_cmd_data, &resp, &fatal)))
4314 done = synprot_error(L_smtp_syntax_error, resp, NULL, errmsg);
4317 smtp_printf("%d %s\r\n", SP_NO_MORE, resp, errmsg);
4318 log_write(0, LOG_MAIN|LOG_REJECT, "rejected XCLIENT from %s: %s",
4319 host_and_ident(FALSE), errmsg);
4323 fl.helo_seen = FALSE; /* Require another EHLO */
4324 smtp_code = string_sprintf("%d", resp);
4326 /*XXX unclear in spec. if this needs to be an ESMTP banner,
4327 nor whether we get the original client's HELO after (or a proxy fake).
4328 We require that we do; the following HELO/EHLO handling will set
4329 sender_helo_name as normal. */
4331 smtp_printf("%s XCLIENT success\r\n", SP_NO_MORE, smtp_code);
4333 break; /* XCLIENT */
4338 /* The MAIL command requires an address as an operand. All we do
4339 here is to parse it for syntactic correctness. The form "<>" is
4340 a special case which converts into an empty string. The start/end
4341 pointers in the original are not used further for this address, as
4342 it is the canonical extracted address which is all that is kept. */
4346 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4348 was_rej_mail = TRUE; /* Reset if accepted */
4349 env_mail_type_t * mail_args; /* Sanity check & validate args */
4352 if ( fl.helo_verify_required
4353 || verify_check_host(&hosts_require_helo) == OK)
4355 smtp_printf("503 HELO or EHLO required\r\n", SP_NO_MORE);
4356 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4357 "HELO/EHLO given", host_and_ident(FALSE));
4360 else if (smtp_mailcmd_max < 0)
4361 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4365 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4366 US"sender already given");
4370 if (!*smtp_cmd_data)
4372 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4373 US"MAIL must have an address operand");
4377 /* Check to see if the limit for messages per connection would be
4378 exceeded by accepting further messages. */
4380 if (smtp_mailcmd_max > 0 && smtp_mailcmd_count > smtp_mailcmd_max)
4382 smtp_printf("421 too many messages in this connection\r\n", SP_NO_MORE);
4383 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4384 "messages in one connection", host_and_ident(TRUE));
4388 /* Reset for start of message - even if this is going to fail, we
4389 obviously need to throw away any previous data. */
4391 cancel_cutthrough_connection(TRUE, US"MAIL received");
4392 reset_point = smtp_reset(reset_point);
4394 sender_data = recipient_data = NULL;
4396 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4398 if (fl.esmtp) for(;;)
4400 uschar *name, *value, *end;
4401 unsigned long int size;
4402 BOOL arg_error = FALSE;
4404 if (!extract_option(&name, &value)) break;
4406 for (mail_args = env_mail_type_list;
4407 mail_args->value != ENV_MAIL_OPT_NULL;
4410 if (strcmpic(name, mail_args->name) == 0)
4412 if (mail_args->need_value && strcmpic(value, US"") == 0)
4415 switch(mail_args->value)
4417 /* Handle SIZE= by reading the value. We don't do the check till later,
4418 in order to be able to log the sender address on failure. */
4419 case ENV_MAIL_OPT_SIZE:
4420 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4422 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4424 message_size = (int)size;
4430 /* If this session was initiated with EHLO and accept_8bitmime is set,
4431 Exim will have indicated that it supports the BODY=8BITMIME option. In
4432 fact, it does not support this according to the RFCs, in that it does not
4433 take any special action for forwarding messages containing 8-bit
4434 characters. That is why accept_8bitmime is not the default setting, but
4435 some sites want the action that is provided. We recognize both "8BITMIME"
4436 and "7BIT" as body types, but take no action. */
4437 case ENV_MAIL_OPT_BODY:
4438 if (accept_8bitmime) {
4439 if (strcmpic(value, US"8BITMIME") == 0)
4441 else if (strcmpic(value, US"7BIT") == 0)
4446 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4447 US"invalid data for BODY");
4450 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4456 /* Handle the two DSN options, but only if configured to do so (which
4457 will have caused "DSN" to be given in the EHLO response). The code itself
4458 is included only if configured in at build time. */
4460 case ENV_MAIL_OPT_RET:
4461 if (fl.dsn_advertised)
4463 /* Check if RET has already been set */
4466 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4467 US"RET can be specified once only");
4470 dsn_ret = strcmpic(value, US"HDRS") == 0
4472 : strcmpic(value, US"FULL") == 0
4475 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4476 /* Check for invalid invalid value, and exit with error */
4479 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4480 US"Value for RET is invalid");
4485 case ENV_MAIL_OPT_ENVID:
4486 if (fl.dsn_advertised)
4488 /* Check if the dsn envid has been already set */
4491 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4492 US"ENVID can be specified once only");
4495 dsn_envid = string_copy(value);
4496 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4500 /* Handle the AUTH extension. If the value given is not "<>" and either
4501 the ACL says "yes" or there is no ACL but the sending host is
4502 authenticated, we set it up as the authenticated sender. However, if the
4503 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4504 the condition is met. The value of AUTH is an xtext, which means that +,
4505 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4507 case ENV_MAIL_OPT_AUTH:
4508 if (Ustrcmp(value, "<>") != 0)
4513 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4515 /* Put back terminator overrides for error message */
4518 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4519 US"invalid data for AUTH");
4522 GET_OPTION("acl_smtp_mailauth");
4523 if (!acl_smtp_mailauth)
4525 ignore_msg = US"client not authenticated";
4526 rc = sender_host_authenticated ? OK : FAIL;
4530 ignore_msg = US"rejected by ACL";
4531 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4532 &user_msg, &log_msg);
4538 if (authenticated_by == NULL ||
4539 authenticated_by->mail_auth_condition == NULL ||
4540 expand_check_condition(authenticated_by->mail_auth_condition,
4541 authenticated_by->name, US"authenticator"))
4542 break; /* Accept the AUTH */
4544 ignore_msg = US"server_mail_auth_condition failed";
4545 if (authenticated_id != NULL)
4546 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4547 ignore_msg, authenticated_id);
4552 authenticated_sender = NULL;
4553 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4554 value, host_and_ident(TRUE), ignore_msg);
4557 /* Should only get DEFER or ERROR here. Put back terminator
4558 overrides for error message */
4563 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4570 #ifndef DISABLE_PRDR
4571 case ENV_MAIL_OPT_PRDR:
4573 prdr_requested = TRUE;
4578 case ENV_MAIL_OPT_UTF8:
4579 if (!fl.smtputf8_advertised)
4581 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4582 US"SMTPUTF8 used when not advertised");
4586 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4587 message_smtputf8 = allow_utf8_domains = TRUE;
4588 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4590 int old_pool = store_pool;
4591 store_pool = POOL_PERM;
4592 received_protocol = string_sprintf("utf8%s", received_protocol);
4593 store_pool = old_pool;
4598 /* No valid option. Stick back the terminator characters and break
4599 the loop. Do the name-terminator second as extract_option sets
4600 value==name when it found no equal-sign.
4601 An error for a malformed address will occur. */
4602 case ENV_MAIL_OPT_NULL:
4610 /* Break out of for loop if switch() had bad argument or
4611 when start of the email address is reached */
4612 if (arg_error) break;
4615 /* If we have passed the threshold for rate limiting, apply the current
4616 delay, and update it for next time, provided this is a limited host. */
4618 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4619 verify_check_host(&smtp_ratelimit_hosts) == OK)
4621 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4622 smtp_delay_mail/1000.0);
4623 millisleep((int)smtp_delay_mail);
4624 smtp_delay_mail *= smtp_rlm_factor;
4625 if (smtp_delay_mail > (double)smtp_rlm_limit)
4626 smtp_delay_mail = (double)smtp_rlm_limit;
4629 /* Now extract the address, first applying any SMTP-time rewriting. The
4630 TRUE flag allows "<>" as a sender address. */
4632 raw_sender = rewrite_existflags & rewrite_smtp
4633 /* deconst ok as smtp_cmd_data was not const */
4634 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4635 global_rewrite_rules)
4639 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4644 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4648 sender_address = raw_sender;
4650 /* If there is a configured size limit for mail, check that this message
4651 doesn't exceed it. The check is postponed to this point so that the sender
4654 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4656 smtp_printf("552 Message size exceeds maximum permitted\r\n", SP_NO_MORE);
4657 log_write(L_size_reject,
4658 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4659 "message too big: size%s=%d max=%d",
4661 host_and_ident(TRUE),
4662 (message_size == INT_MAX)? ">" : "",
4664 thismessage_size_limit);
4665 sender_address = NULL;
4669 /* Check there is enough space on the disk unless configured not to.
4670 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4671 plus the current message - i.e. we accept the message only if it won't
4672 reduce the space below the threshold. Add 5000 to the size to allow for
4673 overheads such as the Received: line and storing of recipients, etc.
4674 By putting the check here, even when SIZE is not given, it allow VRFY
4675 and EXPN etc. to be used when space is short. */
4677 if (!receive_check_fs(
4678 smtp_check_spool_space && message_size >= 0
4679 ? message_size + 5000 : 0))
4681 smtp_printf("452 Space shortage, please try later\r\n", SP_NO_MORE);
4682 sender_address = NULL;
4686 /* If sender_address is unqualified, reject it, unless this is a locally
4687 generated message, or the sending host or net is permitted to send
4688 unqualified addresses - typically local machines behaving as MUAs -
4689 in which case just qualify the address. The flag is set above at the start
4690 of the SMTP connection. */
4692 if (!sender_domain && *sender_address)
4693 if (f.allow_unqualified_sender)
4695 sender_domain = Ustrlen(sender_address) + 1;
4696 /* deconst ok as sender_address was not const */
4697 sender_address = US rewrite_address_qualify(sender_address, FALSE);
4698 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4703 smtp_printf("501 %s: sender address must contain a domain\r\n", SP_NO_MORE,
4705 log_write(L_smtp_syntax_error,
4706 LOG_MAIN|LOG_REJECT,
4707 "unqualified sender rejected: <%s> %s%s",
4709 host_and_ident(TRUE),
4711 sender_address = NULL;
4715 /* Apply an ACL check if one is defined, before responding. Afterwards,
4716 when pipelining is not advertised, do another sync check in case the ACL
4717 delayed and the client started sending in the meantime. */
4719 GET_OPTION("acl_smtp_mail");
4722 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4723 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4729 if (rc == OK || rc == DISCARD)
4731 BOOL more = pipeline_response();
4734 smtp_printf("%s%s%s", more, US"250 OK",
4735 #ifndef DISABLE_PRDR
4736 prdr_requested ? US", PRDR Requested" : US"",
4743 #ifndef DISABLE_PRDR
4745 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4747 smtp_user_msg(US"250", user_msg);
4749 smtp_delay_rcpt = smtp_rlr_base;
4750 f.recipients_discarded = (rc == DISCARD);
4751 was_rej_mail = FALSE;
4755 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4756 sender_address = NULL;
4761 /* The RCPT command requires an address as an operand. There may be any
4762 number of RCPT commands, specifying multiple recipients. We build them all
4763 into a data structure. The start/end values given by parse_extract_address
4764 are not used, as we keep only the extracted address. */
4768 /* We got really to many recipients. A check against configured
4769 limits is done later */
4770 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
4771 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
4773 was_rcpt = fl.rcpt_in_progress = TRUE;
4775 /* There must be a sender address; if the sender was rejected and
4776 pipelining was advertised, we assume the client was pipelining, and do not
4777 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4778 get the same treatment. */
4780 if (!sender_address)
4782 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4784 smtp_printf("503 sender not yet given\r\n", SP_NO_MORE);
4785 was_rej_mail = TRUE;
4789 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4790 US"sender not yet given");
4791 was_rcpt = FALSE; /* Not a valid RCPT */
4797 /* Check for an operand */
4799 if (!smtp_cmd_data[0])
4801 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4802 US"RCPT must have an address operand");
4807 /* Set the DSN flags orcpt and dsn_flags from the session*/
4811 if (fl.esmtp) for(;;)
4813 uschar *name, *value;
4815 if (!extract_option(&name, &value))
4818 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4820 /* Check whether orcpt has been already set */
4823 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4824 US"ORCPT can be specified once only");
4827 orcpt = string_copy(value);
4828 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4831 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4833 /* Check if the notify flags have been already set */
4836 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4837 US"NOTIFY can be specified once only");
4840 if (strcmpic(value, US"NEVER") == 0)
4841 dsn_flags |= rf_notify_never;
4848 while (*pp != 0 && *pp != ',') pp++;
4849 if (*pp == ',') *pp++ = 0;
4850 if (strcmpic(p, US"SUCCESS") == 0)
4852 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4853 dsn_flags |= rf_notify_success;
4855 else if (strcmpic(p, US"FAILURE") == 0)
4857 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4858 dsn_flags |= rf_notify_failure;
4860 else if (strcmpic(p, US"DELAY") == 0)
4862 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4863 dsn_flags |= rf_notify_delay;
4867 /* Catch any strange values */
4868 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4869 US"Invalid value for NOTIFY parameter");
4874 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
4878 /* Unknown option. Stick back the terminator characters and break
4879 the loop. An error for a malformed address will occur. */
4883 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4890 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4891 as a recipient address */
4893 recipient = rewrite_existflags & rewrite_smtp
4894 /* deconst ok as smtp_cmd_data was not const */
4895 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4896 global_rewrite_rules)
4899 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4900 &recipient_domain, FALSE)))
4902 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4907 /* If the recipient address is unqualified, reject it, unless this is a
4908 locally generated message. However, unqualified addresses are permitted
4909 from a configured list of hosts and nets - typically when behaving as
4910 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4911 really. The flag is set at the start of the SMTP connection.
4913 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4914 assumed this meant "reserved local part", but the revision of RFC 821 and
4915 friends now makes it absolutely clear that it means *mailbox*. Consequently
4916 we must always qualify this address, regardless. */
4918 if (!recipient_domain)
4919 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4926 /* Check maximum allowed */
4928 if ( rcpt_count+1 < 0
4929 || rcpt_count > recipients_max_expanded && recipients_max_expanded > 0)
4931 if (recipients_max_reject)
4934 smtp_printf("552 too many recipients\r\n", SP_NO_MORE);
4936 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4937 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4942 smtp_printf("452 too many recipients\r\n", SP_NO_MORE);
4944 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4945 "temporarily rejected: sender=<%s> %s", sender_address,
4946 host_and_ident(TRUE));
4953 /* If we have passed the threshold for rate limiting, apply the current
4954 delay, and update it for next time, provided this is a limited host. */
4956 if (rcpt_count > smtp_rlr_threshold &&
4957 verify_check_host(&smtp_ratelimit_hosts) == OK)
4959 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4960 smtp_delay_rcpt/1000.0);
4961 millisleep((int)smtp_delay_rcpt);
4962 smtp_delay_rcpt *= smtp_rlr_factor;
4963 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4964 smtp_delay_rcpt = (double)smtp_rlr_limit;
4967 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4968 for them. Otherwise, check the access control list for this recipient. As
4969 there may be a delay in this, re-check for a synchronization error
4970 afterwards, unless pipelining was advertised. */
4972 if (f.recipients_discarded)
4976 GET_OPTION("acl_smtp_rcpt");
4977 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4979 && !f.smtp_in_pipelining_advertised && !check_sync())
4983 /* The ACL was happy */
4987 BOOL more = pipeline_response();
4990 smtp_user_msg(US"250", user_msg);
4992 smtp_printf("250 Accepted\r\n", more);
4993 receive_add_recipient(recipient, -1);
4995 /* Set the dsn flags in the recipients_list */
4996 recipients_list[recipients_count-1].orcpt = orcpt;
4997 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
4999 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5000 recipients_list[recipients_count-1].orcpt,
5001 recipients_list[recipients_count-1].dsn_flags); */
5004 /* The recipient was discarded */
5006 else if (rc == DISCARD)
5009 smtp_user_msg(US"250", user_msg);
5011 smtp_printf("250 Accepted\r\n", SP_NO_MORE);
5014 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5015 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5016 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5017 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5018 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5021 /* Either the ACL failed the address, or it was deferred. */
5025 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5026 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5031 /* The DATA command is legal only if it follows successful MAIL FROM
5032 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5033 not counted as a protocol error if it follows RCPT (which must have been
5034 rejected if there are no recipients.) This function is complete when a
5035 valid DATA command is encountered.
5037 Note concerning the code used: RFC 2821 says this:
5039 - If there was no MAIL, or no RCPT, command, or all such commands
5040 were rejected, the server MAY return a "command out of sequence"
5041 (503) or "no valid recipients" (554) reply in response to the
5044 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5045 because it is the same whether pipelining is in use or not.
5047 If all the RCPT commands that precede DATA provoked the same error message
5048 (often indicating some kind of system error), it is helpful to include it
5049 with the DATA rejection (an idea suggested by Tony Finch). */
5056 if (chunking_state != CHUNKING_OFFERED)
5058 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5059 US"BDAT command used when CHUNKING not advertised");
5063 /* grab size, endmarker */
5065 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5067 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5068 US"missing size for BDAT command");
5071 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5072 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5073 chunking_data_left = chunking_datasize;
5074 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5075 (int)chunking_state, chunking_data_left);
5077 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
5086 f.bdat_readers_wanted = FALSE;
5088 DATA_BDAT: /* Common code for DATA and BDAT */
5089 #ifndef DISABLE_PIPE_CONNECT
5090 fl.pipe_connect_acceptable = FALSE;
5092 if (!discarded && recipients_count <= 0)
5094 if (fl.rcpt_smtp_response_same && rcpt_smtp_response)
5096 uschar *code = US"503";
5097 int len = Ustrlen(rcpt_smtp_response);
5098 smtp_respond(code, 3, SR_NOT_FINAL, US"All RCPT commands were rejected with "
5100 /* Responses from smtp_printf() will have \r\n on the end */
5101 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5102 rcpt_smtp_response[len-2] = 0;
5103 smtp_respond(code, 3, SR_NOT_FINAL, rcpt_smtp_response);
5105 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5106 smtp_printf("503 Valid RCPT command must precede %s\r\n", SP_NO_MORE,
5107 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5109 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5110 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5111 ? US"valid RCPT command must precede DATA"
5112 : US"valid RCPT command must precede BDAT");
5114 if (chunking_state > CHUNKING_OFFERED)
5116 bdat_push_receive_functions();
5122 if (toomany && recipients_max_reject)
5124 sender_address = NULL; /* This will allow a new MAIL without RSET */
5125 sender_address_unrewritten = NULL;
5126 smtp_printf("554 Too many recipients\r\n", SP_NO_MORE);
5128 if (chunking_state > CHUNKING_OFFERED)
5130 bdat_push_receive_functions();
5136 if (chunking_state > CHUNKING_OFFERED)
5137 rc = OK; /* There is no predata ACL or go-ahead output for BDAT */
5140 /* If there is a predata-ACL, re-check the synchronization afterwards,
5141 since the ACL may have delayed. To handle cutthrough delivery enforce a
5142 dummy call to get the DATA command sent. */
5144 GET_OPTION("acl_smtp_predata");
5145 if (!acl_smtp_predata && cutthrough.cctx.sock < 0)
5149 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5150 f.enable_dollar_recipients = TRUE;
5151 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5153 f.enable_dollar_recipients = FALSE;
5154 if (rc == OK && !check_sync())
5158 { /* Either the ACL failed the address, or it was deferred. */
5159 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5165 smtp_user_msg(US"354", user_msg);
5168 "354 Enter message, ending with \".\" on a line by itself\r\n", SP_NO_MORE);
5171 if (f.bdat_readers_wanted)
5172 bdat_push_receive_functions();
5175 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5176 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5177 US &on, sizeof(on));
5180 message_ended = END_NOTENDED; /* Indicate in middle of data */
5191 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5192 &start, &end, &recipient_domain, FALSE)))
5194 smtp_printf("501 %s\r\n", SP_NO_MORE, errmess);
5198 if (!recipient_domain)
5199 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5203 GET_OPTION("acl_smtp_vrfy");
5204 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5205 &user_msg, &log_msg)) != OK)
5206 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5210 address_item * addr = deliver_make_addr(address, FALSE);
5212 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5213 -1, -1, NULL, NULL, NULL))
5216 s = string_sprintf("250 <%s> is deliverable", address);
5220 s = (addr->user_message != NULL)?
5221 string_sprintf("451 <%s> %s", address, addr->user_message) :
5222 string_sprintf("451 Cannot resolve <%s> at this time", address);
5226 s = (addr->user_message != NULL)?
5227 string_sprintf("550 <%s> %s", address, addr->user_message) :
5228 string_sprintf("550 <%s> is not deliverable", address);
5229 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5230 smtp_cmd_argument, host_and_ident(TRUE));
5234 smtp_printf("%s\r\n", SP_NO_MORE, s);
5242 GET_OPTION("acl_smtp_expn");
5243 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5245 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5248 BOOL save_log_testing_mode = f.log_testing_mode;
5249 f.address_test_mode = f.log_testing_mode = TRUE;
5250 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5251 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5253 f.address_test_mode = FALSE;
5254 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5263 if (!fl.tls_advertised)
5265 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5266 US"STARTTLS command used when not advertised");
5270 /* Apply an ACL check if one is defined */
5272 GET_OPTION("acl_smtp_starttls");
5273 if ( acl_smtp_starttls
5274 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5275 &user_msg, &log_msg)) != OK
5278 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5282 /* RFC 2487 is not clear on when this command may be sent, though it
5283 does state that all information previously obtained from the client
5284 must be discarded if a TLS session is started. It seems reasonable to
5285 do an implied RSET when STARTTLS is received. */
5287 incomplete_transaction_log(US"STARTTLS");
5288 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5289 reset_point = smtp_reset(reset_point);
5291 cmd_list[CL_STLS].is_mail_cmd = FALSE;
5293 /* There's an attack where more data is read in past the STARTTLS command
5294 before TLS is negotiated, then assumed to be part of the secure session
5295 when used afterwards; we use segregated input buffers, so are not
5296 vulnerable, but we want to note when it happens and, for sheer paranoia,
5297 ensure that the buffer is "wiped".
5298 Pipelining sync checks will normally have protected us too, unless disabled
5299 by configuration. */
5304 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5305 if (tls_in.active.sock < 0)
5306 smtp_inend = smtp_inptr = smtp_inbuffer;
5307 /* and if TLS is already active, tls_server_start() should fail */
5310 /* There is nothing we value in the input buffer and if TLS is successfully
5311 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5312 fresh content into it. The buffer contains arbitrary content from an
5313 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5314 It seems safest to just wipe away the content rather than leave it as a
5315 target to jump to. */
5317 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5319 /* Attempt to start up a TLS session, and if successful, discard all
5320 knowledge that was obtained previously. At least, that's what the RFC says,
5321 and that's what happens by default. However, in order to work round YAEB,
5322 there is an option to remember the esmtp state. Sigh.
5324 We must allow for an extra EHLO command and an extra AUTH command after
5325 STARTTLS that don't add to the nonmail command count. */
5328 if ((rc = tls_server_start(&s)) == OK)
5330 if (!tls_remember_esmtp)
5331 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5332 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
5333 cmd_list[CL_AUTH].is_mail_cmd = TRUE;
5334 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
5335 if (sender_helo_name)
5337 sender_helo_name = NULL;
5338 host_build_sender_fullhost(); /* Rebuild */
5339 set_process_info("handling incoming TLS connection from %s",
5340 host_and_ident(FALSE));
5343 (sender_host_address ? protocols : protocols_local)
5345 ? pextend + (sender_host_authenticated ? pauthed : 0)
5347 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5350 sender_host_auth_pubname = sender_host_authenticated = NULL;
5351 authenticated_id = NULL;
5352 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5353 DEBUG(D_tls) debug_printf("TLS active\n");
5354 break; /* Successful STARTTLS */
5357 (void) smtp_log_tls_fail(s);
5359 /* Some local configuration problem was discovered before actually trying
5360 to do a TLS handshake; give a temporary error. */
5364 smtp_printf("454 TLS currently unavailable\r\n", SP_NO_MORE);
5368 /* Hard failure. Reject everything except QUIT or closed connection. One
5369 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5370 set, but we must still reject all incoming commands. Another is a handshake
5371 failure - and there may some encrypted data still in the pipe to us, which we
5372 see as garbage commands. */
5374 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5375 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5378 log_close_event(US"by EOF");
5379 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5383 /* It is perhaps arguable as to which exit ACL should be called here,
5384 but as it is probably a situation that almost never arises, it
5385 probably doesn't matter. We choose to call the real QUIT ACL, which in
5386 some sense is perhaps "right". */
5389 f.smtp_in_quit = TRUE;
5391 GET_OPTION("acl_smtp_quit");
5393 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5394 &log_msg)) == ERROR))
5395 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5398 smtp_respond(US"221", 3, SR_FINAL, user_msg);
5400 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
5401 log_close_event(US"by QUIT");
5406 smtp_printf("554 Security failure\r\n", SP_NO_MORE);
5409 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5414 /* The ACL for QUIT is provided for gathering statistical information or
5415 similar; it does not affect the response code, but it can supply a custom
5419 smtp_quit_handler(&user_msg, &log_msg);
5425 smtp_rset_handler();
5426 cancel_cutthrough_connection(TRUE, US"RSET received");
5427 reset_point = smtp_reset(reset_point);
5434 smtp_printf("250 OK\r\n", SP_NO_MORE);
5438 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5439 used, a check will be done for permitted hosts. Show STARTTLS only if not
5440 already in a TLS session and if it would be advertised in the EHLO
5445 smtp_printf("214-Commands supported:\r\n214", SP_MORE);
5446 smtp_printf(" AUTH", SP_MORE);
5448 if (tls_in.active.sock < 0 &&
5449 verify_check_host(&tls_advertise_hosts) != FAIL)
5450 smtp_printf(" STARTTLS", SP_MORE);
5452 smtp_printf(" HELO EHLO MAIL RCPT DATA BDAT", SP_MORE);
5453 smtp_printf(" NOOP QUIT RSET HELP", SP_MORE);
5454 if (acl_smtp_etrn) smtp_printf(" ETRN", SP_MORE);
5455 if (acl_smtp_expn) smtp_printf(" EXPN", SP_MORE);
5456 if (acl_smtp_vrfy) smtp_printf(" VRFY", SP_MORE);
5457 #ifdef EXPERIMENTAL_XCLIENT
5458 if (proxy_session || verify_check_host(&hosts_xclient) != FAIL)
5459 smtp_printf(" XCLIENT", SP_MORE);
5461 smtp_printf("\r\n", SP_NO_MORE);
5466 incomplete_transaction_log(US"connection lost");
5467 smtp_notquit_exit(US"connection-lost", US"421",
5468 US"%s lost input connection", smtp_active_hostname);
5470 /* Don't log by default unless in the middle of a message, as some mailers
5471 just drop the call rather than sending QUIT, and it clutters up the logs.
5474 if (sender_address || recipients_count > 0)
5475 log_write(L_lost_incoming_connection, LOG_MAIN,
5476 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5477 f.sender_host_unknown ? "EOF" : "disconnection",
5478 f.tcp_in_fastopen_logged
5481 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5483 host_and_ident(FALSE), smtp_read_error,
5484 string_timesince(&smtp_connection_start)
5488 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5489 smtp_get_connection_info(),
5490 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5492 string_timesince(&smtp_connection_start)
5503 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5504 US"ETRN is not permitted inside a transaction");
5508 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5509 host_and_ident(FALSE));
5511 GET_OPTION("acl_smtp_etrn");
5512 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5513 &user_msg, &log_msg)) != OK)
5515 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5519 /* Compute the serialization key for this command. */
5521 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5523 /* If a command has been specified for running as a result of ETRN, we
5524 permit any argument to ETRN. If not, only the # standard form is permitted,
5525 since that is strictly the only kind of ETRN that can be implemented
5526 according to the RFC. */
5528 GET_OPTION("smtp_etrn_command");
5529 if (smtp_etrn_command)
5533 etrn_command = smtp_etrn_command;
5534 deliver_domain = smtp_cmd_data;
5535 rc = transport_set_up_command(&argv, smtp_etrn_command, TSUC_EXPAND_ARGS, 0, NULL,
5536 US"ETRN processing", &error);
5537 deliver_domain = NULL;
5540 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5542 smtp_printf("458 Internal failure\r\n", SP_NO_MORE);
5547 /* Else set up to call Exim with the -R option. */
5551 if (*smtp_cmd_data++ != '#')
5553 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5554 US"argument must begin with #");
5557 etrn_command = US"exim -R";
5558 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5559 *queue_name ? 4 : 2,
5560 US"-R", smtp_cmd_data,
5561 US"-MCG", queue_name);
5564 /* If we are host-testing, don't actually do anything. */
5570 debug_printf("ETRN command is: %s\n", etrn_command);
5571 debug_printf("ETRN command execution skipped\n");
5573 if (user_msg == NULL) smtp_printf("250 OK\r\n", SP_NO_MORE);
5574 else smtp_user_msg(US"250", user_msg);
5579 /* If ETRN queue runs are to be serialized, check the database to
5580 ensure one isn't already running. */
5582 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5584 smtp_printf("458 Already processing %s\r\n", SP_NO_MORE, smtp_cmd_data);
5588 /* Fork a child process and run the command. We don't want to have to
5589 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5590 forking. It should be set that way anyway for external incoming SMTP,
5591 but we save and restore to be tidy. If serialization is required, we
5592 actually run the command in yet another process, so we can wait for it
5593 to complete and then remove the serialization lock. */
5595 oldsignal = signal(SIGCHLD, SIG_IGN);
5597 if ((pid = exim_fork(US"etrn-command")) == 0)
5599 smtp_input = FALSE; /* This process is not associated with the */
5600 (void)fclose(smtp_in); /* SMTP call any more. */
5601 (void)fclose(smtp_out);
5603 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5605 /* If not serializing, do the exec right away. Otherwise, fork down
5606 into another process. */
5608 if ( !smtp_etrn_serialize
5609 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5611 DEBUG(D_exec) debug_print_argv(argv);
5612 exim_nullstd(); /* Ensure std{in,out,err} exist */
5613 /* argv[0] should be untainted, from child_exec_exim() */
5614 execv(CS argv[0], (char *const *)argv);
5615 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5616 etrn_command, strerror(errno));
5617 _exit(EXIT_FAILURE); /* paranoia */
5620 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5621 is, we are in the first subprocess, after forking again. All we can do
5622 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5623 complete, before removing the serialization. */
5626 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5627 "failed: %s", strerror(errno));
5631 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5633 (void)wait(&status);
5634 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5638 enq_end(etrn_serialize_key);
5639 exim_underbar_exit(EXIT_SUCCESS);
5642 /* Back in the top level SMTP process. Check that we started a subprocess
5643 and restore the signal state. */
5647 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5649 smtp_printf("458 Unable to fork process\r\n", SP_NO_MORE);
5650 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5654 smtp_printf("250 OK\r\n", SP_NO_MORE);
5656 smtp_user_msg(US"250", user_msg);
5658 signal(SIGCHLD, oldsignal);
5663 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5664 US"unexpected argument data");
5668 /* This currently happens only for NULLs, but could be extended. */
5671 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5672 US"NUL character(s) present (shown as '?')");
5673 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5681 unsigned nchars = 150;
5682 uschar * buf = receive_getbuf(&nchars); /* destructive read */
5684 incomplete_transaction_log(US"sync failure");
5685 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5686 "(next input sent too soon: pipelining was%s advertised): "
5687 "rejected \"%s\" %s next input=\"%s\" (%u bytes)",
5688 f.smtp_in_pipelining_advertised ? "" : " not",
5689 smtp_cmd_buffer, host_and_ident(TRUE),
5690 string_printing(buf), nchars);
5691 smtp_notquit_exit(US"synchronization-error", US"554",
5692 US"SMTP synchronization error");
5693 done = 1; /* Pretend eof - drops connection */
5698 case TOO_MANY_NONMAIL_CMD:
5699 s = smtp_cmd_buffer;
5701 incomplete_transaction_log(US"too many non-mail commands");
5702 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5703 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5704 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5705 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5706 done = 1; /* Pretend eof - drops connection */
5709 #ifdef SUPPORT_PROXY
5710 case PROXY_FAIL_IGNORE_CMD:
5711 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", SP_NO_MORE);
5716 if (unknown_command_count++ >= smtp_max_unknown_commands)
5718 log_write(L_smtp_syntax_error, LOG_MAIN,
5719 "SMTP syntax error in \"%s\" %s %s",
5720 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5721 US"unrecognized command");
5722 incomplete_transaction_log(US"unrecognized command");
5723 smtp_notquit_exit(US"bad-commands", US"500",
5724 US"Too many unrecognized commands");
5726 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5727 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5728 string_printing(smtp_cmd_buffer));
5731 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5732 US"unrecognized command");
5736 /* This label is used by goto's inside loops that want to break out to
5737 the end of the command-processing loop. */
5740 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5741 last_was_rcpt = was_rcpt; /* protocol error handling */
5744 return done - 2; /* Convert yield values */
5750 authres_smtpauth(gstring * g)
5752 if (!sender_host_authenticated)
5755 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5757 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
5758 g = authenticated_id
5759 ? string_append(g, 2, US") x509.auth=", authenticated_id)
5760 : string_cat(g, US") reason=x509.auth");
5762 g = authenticated_id
5763 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
5764 : string_cat(g, US", no id saved)");
5766 if (authenticated_sender)
5767 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5775 /* End of smtp_in.c */