1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) The Exim Maintainers 2020 - 2023 */
6 /* Copyright (c) University of Cambridge 1995 - 2018 */
7 /* See the file NOTICE for conditions of use and distribution. */
8 /* SPDX-License-Identifier: GPL-2.0-or-later */
10 /* Functions for handling an incoming SMTP call. */
17 /* Initialize for TCP wrappers if so configured. It appears that the macro
18 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
19 including that header, and restore its value afterwards. */
21 #ifdef USE_TCP_WRAPPERS
24 #define EXIM_HAVE_IPV6
30 #define HAVE_IPV6 TRUE
33 int allow_severity = LOG_INFO;
34 int deny_severity = LOG_NOTICE;
35 uschar *tcp_wrappers_name;
39 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
40 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
41 commands that accept arguments, and this in particular applies to AUTH, where
42 the data can be quite long. More recently this value was 2048 in Exim;
43 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
44 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
45 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
46 we need room to handle large base64-encoded AUTHs for GSSAPI.
49 #define SMTP_CMD_BUFFER_SIZE 16384
51 /* Size of buffer for reading SMTP incoming packets */
53 #define IN_BUFFER_SIZE 8192
55 /* Structure for SMTP command list */
62 short int is_mail_cmd;
65 /* Codes for identifying commands. We order them so that those that come first
66 are those for which synchronization is always required. Checking this can help
70 /* These commands are required to be synchronized, i.e. to be the last in a
71 block of commands when pipelining. */
73 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
74 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
75 ETRN_CMD, /* This by analogy with TURN from the RFC */
76 STARTTLS_CMD, /* Required by the STARTTLS RFC */
77 TLS_AUTH_CMD, /* auto-command at start of SSL */
78 #ifdef EXPERIMENTAL_XCLIENT
79 XCLIENT_CMD, /* per xlexkiro implementation */
82 /* This is a dummy to identify the non-sync commands when pipelining */
84 NON_SYNC_CMD_PIPELINING,
86 /* These commands need not be synchronized when pipelining */
88 MAIL_CMD, RCPT_CMD, RSET_CMD,
90 /* This is a dummy to identify the non-sync commands when not pipelining */
92 NON_SYNC_CMD_NON_PIPELINING,
94 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
95 processed the message is sent using a series of BDAT commands"
96 implies that BDAT should be synchronized. However, we see Google, at least,
97 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
98 processing of the RCPT response(s). We shall do the same, and not require
99 synch for BDAT. Worse, as the chunk may (very likely will) follow the
100 command-header in the same packet we cannot do the usual "is there any
101 follow-on data after the command line" even for non-pipeline mode.
102 So we'll need an explicit check after reading the expected chunk amount
103 when non-pipe, before sending the ACK. */
107 /* I have been unable to find a statement about the use of pipelining
108 with AUTH, so to be on the safe side it is here, though I kind of feel
109 it should be up there with the synchronized commands. */
113 /* I'm not sure about these, but I don't think they matter. */
118 PROXY_FAIL_IGNORE_CMD,
121 /* These are specials that don't correspond to actual commands */
123 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
124 TOO_MANY_NONMAIL_CMD };
127 /* This is a convenience macro for adding the identity of an SMTP command
128 to the circular buffer that holds a list of the last n received. */
131 smtp_connection_had[smtp_ch_index++] = n; \
132 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
135 /*************************************************
136 * Local static variables *
137 *************************************************/
140 BOOL auth_advertised :1;
142 BOOL tls_advertised :1;
144 BOOL dsn_advertised :1;
146 BOOL helo_verify_required :1;
149 BOOL helo_accept_junk :1;
150 #ifndef DISABLE_PIPE_CONNECT
151 BOOL pipe_connect_acceptable :1;
153 BOOL rcpt_smtp_response_same :1;
154 BOOL rcpt_in_progress :1;
155 BOOL smtp_exit_function_called :1;
157 BOOL smtputf8_advertised :1;
160 .helo_verify_required = FALSE,
161 .helo_verify = FALSE,
162 .smtp_exit_function_called = FALSE,
165 static auth_instance *authenticated_by;
166 static int count_nonmail;
167 static int nonmail_command_count;
168 static int synprot_error_count;
169 static int unknown_command_count;
170 static int sync_cmd_limit;
171 static int smtp_write_error = 0;
173 static uschar *rcpt_smtp_response;
174 static uschar *smtp_data_buffer;
175 static uschar *smtp_cmd_data;
177 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
178 final fields of all except AUTH are forced TRUE at the start of a new message
179 setup, to allow one of each between messages that is not counted as a nonmail
180 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
181 allow a new EHLO after starting up TLS.
183 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
184 counted. However, the flag is changed when AUTH is received, so that multiple
185 failing AUTHs will eventually hit the limit. After a successful AUTH, another
186 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
187 forced TRUE, to allow for the re-authentication that can happen at that point.
189 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
190 count of non-mail commands and possibly provoke an error.
192 tls_auth is a pseudo-command, never expected in input. It is activated
193 on TLS startup and looks for a tls authenticator. */
204 #ifdef EXPERIMENTAL_XCLIENT
209 static smtp_cmd_list cmd_list[] = {
210 /* name len cmd has_arg is_mail_cmd */
212 [CL_RSET] = { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
213 [CL_HELO] = { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
214 [CL_EHLO] = { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
215 [CL_AUTH] = { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
217 [CL_STLS] = { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
218 [CL_TLAU] = { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
220 #ifdef EXPERIMENTAL_XCLIENT
221 [CL_XCLI] = { "xclient", sizeof("xclient")-1, XCLIENT_CMD, TRUE, FALSE },
224 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
225 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
226 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
227 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
228 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
229 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
230 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
231 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
232 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
233 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
236 /* This list of names is used for performing the smtp_no_mail logging action. */
238 uschar * smtp_names[] =
240 [SCH_NONE] = US"NONE",
241 [SCH_AUTH] = US"AUTH",
242 [SCH_DATA] = US"DATA",
243 [SCH_BDAT] = US"BDAT",
244 [SCH_EHLO] = US"EHLO",
245 [SCH_ETRN] = US"ETRN",
246 [SCH_EXPN] = US"EXPN",
247 [SCH_HELO] = US"HELO",
248 [SCH_HELP] = US"HELP",
249 [SCH_MAIL] = US"MAIL",
250 [SCH_NOOP] = US"NOOP",
251 [SCH_QUIT] = US"QUIT",
252 [SCH_RCPT] = US"RCPT",
253 [SCH_RSET] = US"RSET",
254 [SCH_STARTTLS] = US"STARTTLS",
255 [SCH_VRFY] = US"VRFY",
256 #ifdef EXPERIMENTAL_XCLIENT
257 [SCH_XCLIENT] = US"XCLIENT",
261 static uschar *protocols_local[] = {
262 US"local-smtp", /* HELO */
263 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
264 US"local-esmtp", /* EHLO */
265 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
266 US"local-esmtpa", /* EHLO->AUTH */
267 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
269 static uschar *protocols[] = {
271 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
272 US"esmtp", /* EHLO */
273 US"esmtps", /* EHLO->STARTTLS->EHLO */
274 US"esmtpa", /* EHLO->AUTH */
275 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
280 #define pcrpted 1 /* added to pextend or pnormal */
281 #define pauthed 2 /* added to pextend */
283 /* Sanity check and validate optional args to MAIL FROM: envelope */
286 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
290 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
296 uschar * name; /* option requested during MAIL cmd */
297 int value; /* enum type */
298 BOOL need_value; /* TRUE requires value (name=value pair format)
299 FALSE is a singleton */
301 static env_mail_type_t env_mail_type_list[] = {
302 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
303 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
304 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
306 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
308 { US"RET", ENV_MAIL_OPT_RET, TRUE },
309 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
311 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
313 /* keep this the last entry */
314 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
317 /* When reading SMTP from a remote host, we have to use our own versions of the
318 C input-reading functions, in order to be able to flush the SMTP output only
319 when about to read more data from the socket. This is the only way to get
320 optimal performance when the client is using pipelining. Flushing for every
321 command causes a separate packet and reply packet each time; saving all the
322 responses up (when pipelining) combines them into one packet and one response.
324 For simplicity, these functions are used for *all* SMTP input, not only when
325 receiving over a socket. However, after setting up a secure socket (SSL), input
326 is read via the OpenSSL library, and another set of functions is used instead
329 These functions are set in the receive_getc etc. variables and called with the
330 same interface as the C functions. However, since there can only ever be
331 one incoming SMTP call, we just use a single buffer and flags. There is no need
332 to implement a complicated private FILE-like structure.*/
334 static uschar *smtp_inbuffer;
335 static uschar *smtp_inptr;
336 static uschar *smtp_inend;
337 static int smtp_had_eof;
338 static int smtp_had_error;
341 /* forward declarations */
342 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
343 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
344 static void smtp_quit_handler(uschar **, uschar **);
345 static void smtp_rset_handler(void);
347 /*************************************************
348 * Log incomplete transactions *
349 *************************************************/
351 /* This function is called after a transaction has been aborted by RSET, QUIT,
352 connection drops or other errors. It logs the envelope information received
353 so far in order to preserve address verification attempts.
355 Argument: string to indicate what aborted the transaction
360 incomplete_transaction_log(uschar * what)
362 if (!sender_address /* No transaction in progress */
363 || !LOGGING(smtp_incomplete_transaction))
366 /* Build list of recipients for logging */
368 if (recipients_count > 0)
370 raw_recipients = store_get(recipients_count * sizeof(uschar *), GET_UNTAINTED);
371 for (int i = 0; i < recipients_count; i++)
372 raw_recipients[i] = recipients_list[i].address;
373 raw_recipients_count = recipients_count;
376 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
377 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
383 log_close_event(const uschar * reason)
385 log_write(L_smtp_connection, LOG_MAIN, "%s D=%s closed %s",
386 smtp_get_connection_info(), string_timesince(&smtp_connection_start), reason);
391 smtp_command_timeout_exit(void)
393 log_write(L_lost_incoming_connection,
394 LOG_MAIN, "SMTP command timeout on%s connection from %s D=%s",
395 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE),
396 string_timesince(&smtp_connection_start));
397 if (smtp_batched_input)
398 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
399 smtp_notquit_exit(US"command-timeout", US"421",
400 US"%s: SMTP command timeout - closing connection",
401 smtp_active_hostname);
402 exim_exit(EXIT_FAILURE);
406 smtp_command_sigterm_exit(void)
408 log_close_event(US"after SIGTERM");
409 if (smtp_batched_input)
410 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
411 smtp_notquit_exit(US"signal-exit", US"421",
412 US"%s: Service not available - closing connection", smtp_active_hostname);
413 exim_exit(EXIT_FAILURE);
417 smtp_data_timeout_exit(void)
419 log_write(L_lost_incoming_connection, LOG_MAIN,
420 "SMTP data timeout (message abandoned) on connection from %s F=<%s> D=%s",
421 sender_fullhost ? sender_fullhost : US"local process", sender_address,
422 string_timesince(&smtp_connection_start));
423 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
424 /* Does not return */
428 smtp_data_sigint_exit(void)
430 log_close_event(had_data_sigint == SIGTERM ? US"SIGTERM":US"SIGINT");
431 receive_bomb_out(US"signal-exit",
432 US"Service not available - SIGTERM or SIGINT received");
433 /* Does not return */
437 /******************************************************************************/
438 /* SMTP input buffer handling. Most of these are similar to stdio routines. */
443 /* Set up the buffer for inputting using direct read() calls, and arrange to
444 call the local functions instead of the standard C ones. Place a NUL at the
445 end of the buffer to safety-stop C-string reads from it. */
447 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
448 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
449 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
451 smtp_inptr = smtp_inend = smtp_inbuffer;
452 smtp_had_eof = smtp_had_error = 0;
457 /* Refill the buffer, and notify DKIM verification code.
458 Return false for error or EOF.
462 smtp_refill(unsigned lim)
466 if (!smtp_out) return FALSE;
468 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
470 /* Limit amount read, so non-message data is not fed to DKIM.
471 Take care to not touch the safety NUL at the end of the buffer. */
473 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
475 if (smtp_receive_timeout > 0) ALARM_CLR(0);
478 /* Must put the error text in fixed store, because this might be during
479 header reading, where it releases unused store above the header. */
482 if (had_command_timeout) /* set by signal handler */
483 smtp_command_timeout_exit(); /* does not return */
484 if (had_command_sigterm)
485 smtp_command_sigterm_exit();
486 if (had_data_timeout)
487 smtp_data_timeout_exit();
489 smtp_data_sigint_exit();
491 smtp_had_error = save_errno;
492 smtp_read_error = string_copy_perm(
493 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
500 dkim_exim_verify_feed(smtp_inbuffer, rc);
502 smtp_inend = smtp_inbuffer + rc;
503 smtp_inptr = smtp_inbuffer;
508 /* Check if there is buffered data */
513 return smtp_inptr < smtp_inend;
516 /* SMTP version of getc()
518 This gets the next byte from the SMTP input buffer. If the buffer is empty,
519 it flushes the output, and refills the buffer, with a timeout. The signal
520 handler is set appropriately by the calling function. This function is not used
521 after a connection has negotiated itself into an TLS/SSL state.
523 Arguments: lim Maximum amount to read/buffer
524 Returns: the next character or EOF
528 smtp_getc(unsigned lim)
530 if (!smtp_hasc() && !smtp_refill(lim)) return EOF;
531 return *smtp_inptr++;
534 /* Get many bytes, refilling buffer if needed */
537 smtp_getbuf(unsigned * len)
542 if (!smtp_hasc() && !smtp_refill(*len))
543 { *len = 0; return NULL; }
545 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
552 /* Copy buffered data to the dkim feed.
553 Called, unless TLS, just before starting to read message headers. */
556 smtp_get_cache(unsigned lim)
559 int n = smtp_inend - smtp_inptr;
563 dkim_exim_verify_feed(smtp_inptr, n);
568 /* SMTP version of ungetc()
569 Puts a character back in the input buffer. Only ever called once.
574 Returns: the character
580 if (smtp_inptr <= smtp_inbuffer) /* NB: NOT smtp_hasc() ! */
581 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "buffer underflow in smtp_ungetc");
588 /* SMTP version of feof()
589 Tests for a previous EOF
592 Returns: non-zero if the eof flag is set
602 /* SMTP version of ferror()
603 Tests for a previous read error, and returns with errno
604 restored to what it was when the error was detected.
607 Returns: non-zero if the error flag is set
613 errno = smtp_had_error;
614 return smtp_had_error;
618 /* Check if a getc will block or not */
621 smtp_could_getc(void)
625 struct timeval tzero = {.tv_sec = 0, .tv_usec = 0};
627 if (smtp_inptr < smtp_inend)
630 fd = fileno(smtp_in);
633 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
635 if (rc <= 0) return FALSE; /* Not ready to read */
636 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
637 if (rc < 0) return FALSE; /* End of file or error */
644 /******************************************************************************/
645 /*************************************************
646 * Recheck synchronization *
647 *************************************************/
649 /* Synchronization checks can never be perfect because a packet may be on its
650 way but not arrived when the check is done. Normally, the checks happen when
651 commands are read: Exim ensures that there is no more input in the input buffer.
652 In normal cases, the response to the command will be fast, and there is no
655 However, for some commands an ACL is run, and that can include delays. In those
656 cases, it is useful to do another check on the input just before sending the
657 response. This also applies at the start of a connection. This function does
658 that check by means of the select() function, as long as the facility is not
659 disabled or inappropriate. A failure of select() is ignored.
661 When there is unwanted input, we read it so that it appears in the log of the
665 Returns: TRUE if all is well; FALSE if there is input pending
669 wouldblock_reading(void)
672 if (tls_in.active.sock >= 0)
673 return !tls_could_getc();
676 return !smtp_could_getc();
682 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
685 return wouldblock_reading();
689 /******************************************************************************/
690 /* Variants of the smtp_* input handling functions for use in CHUNKING mode */
692 /* Forward declarations */
693 static inline void bdat_push_receive_functions(void);
694 static inline void bdat_pop_receive_functions(void);
697 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
698 previous BDAT chunk and getting new ones when we run out. Uses the
699 underlying smtp_getc or tls_getc both for that and for getting the
700 (buffered) data byte. EOD signals (an expected) no further data.
701 ERR signals a protocol error, and EOF a closed input stream.
703 Called from read_bdat_smtp() in receive.c for the message body, but also
704 by the headers read loop in receive_msg(); manipulates chunking_state
705 to handle the BDAT command/response.
706 Placed here due to the correlation with the above smtp_getc(), which it wraps,
707 and also by the need to do smtp command/response handling.
709 Arguments: lim (ignored)
710 Returns: the next character or ERR, EOD or EOF
714 bdat_getc(unsigned lim)
716 uschar * user_msg = NULL;
725 if (chunking_data_left > 0)
726 return lwr_receive_getc(chunking_data_left--);
728 bdat_pop_receive_functions();
730 dkim_save = dkim_collect_input;
731 dkim_collect_input = 0;
734 /* Unless PIPELINING was offered, there should be no next command
735 until after we ack that chunk */
737 if (!f.smtp_in_pipelining_advertised && !check_sync())
739 unsigned n = smtp_inend - smtp_inptr;
742 incomplete_transaction_log(US"sync failure");
743 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
744 "(next input sent too soon: pipelining was not advertised): "
745 "rejected \"%s\" %s next input=\"%s\"%s",
746 smtp_cmd_buffer, host_and_ident(TRUE),
747 string_printing(string_copyn(smtp_inptr, n)),
748 smtp_inend - smtp_inptr > n ? "..." : "");
749 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
750 US"SMTP synchronization error");
751 goto repeat_until_rset;
754 /* If not the last, ack the received chunk. The last response is delayed
755 until after the data ACL decides on it */
757 if (chunking_state == CHUNKING_LAST)
760 dkim_collect_input = dkim_save;
761 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
762 dkim_collect_input = 0;
767 smtp_printf("250 %u byte chunk received\r\n", SP_NO_MORE, chunking_datasize);
768 chunking_state = CHUNKING_OFFERED;
769 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
771 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
772 QUIT, RSET or NOOP but handling them seems obvious */
775 switch(smtp_read_command(TRUE, 1))
778 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
779 US"only BDAT permissible after non-LAST BDAT");
782 switch(smtp_read_command(TRUE, 1))
784 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
785 case EOF_CMD: return EOF;
786 case RSET_CMD: smtp_rset_handler(); return ERR;
787 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
788 US"only RSET accepted now") > 0)
790 goto repeat_until_rset;
794 smtp_quit_handler(&user_msg, &log_msg);
805 smtp_printf("250 OK\r\n", SP_NO_MORE);
812 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
814 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
815 US"missing size for BDAT command");
818 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
819 ? CHUNKING_LAST : CHUNKING_ACTIVE;
820 chunking_data_left = chunking_datasize;
821 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
822 (int)chunking_state, chunking_data_left);
824 if (chunking_datasize == 0)
825 if (chunking_state == CHUNKING_LAST)
829 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
830 US"zero size for BDAT command");
831 goto repeat_until_rset;
834 bdat_push_receive_functions();
836 dkim_collect_input = dkim_save;
838 break; /* to top of main loop */
847 if (chunking_data_left > 0)
848 return lwr_receive_hasc();
853 bdat_getbuf(unsigned * len)
857 if (chunking_data_left <= 0)
858 { *len = 0; return NULL; }
860 if (*len > chunking_data_left) *len = chunking_data_left;
861 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
862 chunking_data_left -= *len;
867 bdat_flush_data(void)
869 while (chunking_data_left)
871 unsigned n = chunking_data_left;
872 if (!bdat_getbuf(&n)) break;
875 bdat_pop_receive_functions();
876 chunking_state = CHUNKING_OFFERED;
877 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
882 bdat_push_receive_functions(void)
884 /* push the current receive_* function on the "stack", and
885 replace them by bdat_getc(), which in turn will use the lwr_receive_*
886 functions to do the dirty work. */
887 if (!lwr_receive_getc)
889 lwr_receive_getc = receive_getc;
890 lwr_receive_getbuf = receive_getbuf;
891 lwr_receive_hasc = receive_hasc;
892 lwr_receive_ungetc = receive_ungetc;
896 DEBUG(D_receive) debug_printf("chunking double-push receive functions\n");
899 receive_getc = bdat_getc;
900 receive_getbuf = bdat_getbuf;
901 receive_hasc = bdat_hasc;
902 receive_ungetc = bdat_ungetc;
906 bdat_pop_receive_functions(void)
908 if (!lwr_receive_getc)
910 DEBUG(D_receive) debug_printf("chunking double-pop receive functions\n");
913 receive_getc = lwr_receive_getc;
914 receive_getbuf = lwr_receive_getbuf;
915 receive_hasc = lwr_receive_hasc;
916 receive_ungetc = lwr_receive_ungetc;
918 lwr_receive_getc = NULL;
919 lwr_receive_getbuf = NULL;
920 lwr_receive_hasc = NULL;
921 lwr_receive_ungetc = NULL;
927 chunking_data_left++;
928 bdat_push_receive_functions(); /* we're not done yet, calling push is safe, because it checks the state before pushing anything */
929 return lwr_receive_ungetc(ch);
934 /******************************************************************************/
936 /*************************************************
937 * Write formatted string to SMTP channel *
938 *************************************************/
940 /* This is a separate function so that we don't have to repeat everything for
941 TLS support or debugging. It is global so that the daemon and the
942 authentication functions can use it. It does not return any error indication,
943 because major problems such as dropped connections won't show up till an output
944 flush for non-TLS connections. The smtp_fflush() function is available for
945 checking that: for convenience, TLS output errors are remembered here so that
946 they are also picked up later by smtp_fflush().
948 This function is exposed to the local_scan API; do not change the signature.
952 more further data expected
953 ... optional arguments
959 smtp_printf(const char *format, BOOL more, ...)
964 smtp_vprintf(format, more, ap);
968 /* This is split off so that verify.c:respond_printf() can, in effect, call
969 smtp_printf(), bearing in mind that in C a vararg function can't directly
970 call another vararg function, only a function which accepts a va_list.
972 This function is exposed to the local_scan API; do not change the signature.
974 /*XXX consider passing caller-info in, for string_vformat-onward */
977 smtp_vprintf(const char *format, BOOL more, va_list ap)
979 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
982 /* Use taint-unchecked routines for writing into big_buffer, trusting
983 that we'll never expand it. */
985 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
986 string_from_gstring(&gs);
988 DEBUG(D_receive) for (const uschar * t, * s = gs.s;
989 s && (t = Ustrchr(s, '\r'));
990 s = t + 2) /* \r\n */
991 debug_printf("%s %.*s\n",
992 s == gs.s ? "SMTP>>" : " ",
997 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
998 smtp_closedown(US"Unexpected error");
999 exim_exit(EXIT_FAILURE);
1002 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
1003 have had the same. Note: this code is also present in smtp_respond(). It would
1004 be tidier to have it only in one place, but when it was added, it was easier to
1005 do it that way, so as not to have to mess with the code for the RCPT command,
1006 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
1008 if (fl.rcpt_in_progress)
1010 if (!rcpt_smtp_response)
1011 rcpt_smtp_response = string_copy(big_buffer);
1012 else if (fl.rcpt_smtp_response_same &&
1013 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
1014 fl.rcpt_smtp_response_same = FALSE;
1015 fl.rcpt_in_progress = FALSE;
1018 /* Now write the string */
1022 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
1024 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
1026 smtp_write_error = -1;
1031 /*************************************************
1032 * Flush SMTP out and check for error *
1033 *************************************************/
1035 /* This function isn't currently used within Exim (it detects errors when it
1036 tries to read the next SMTP input), but is available for use in local_scan().
1037 It flushes the output and checks for errors.
1040 Returns: 0 for no error; -1 after an error
1046 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
1050 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
1052 (fflush(smtp_out) != 0)
1054 smtp_write_error = -1;
1056 return smtp_write_error;
1061 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
1062 a reponse with the one following. */
1065 pipeline_response(void)
1067 if ( !smtp_enforce_sync || !sender_host_address
1068 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
1071 if (wouldblock_reading()) return FALSE;
1072 f.smtp_in_pipelining_used = TRUE;
1077 #ifndef DISABLE_PIPE_CONNECT
1079 pipeline_connect_sends(void)
1081 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
1084 if (wouldblock_reading()) return FALSE;
1085 f.smtp_in_early_pipe_used = TRUE;
1090 /*************************************************
1091 * SMTP command read timeout *
1092 *************************************************/
1094 /* Signal handler for timing out incoming SMTP commands. This attempts to
1097 Argument: signal number (SIGALRM)
1102 command_timeout_handler(int sig)
1104 had_command_timeout = sig;
1109 /*************************************************
1110 * SIGTERM received *
1111 *************************************************/
1113 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1115 Argument: signal number (SIGTERM)
1120 command_sigterm_handler(int sig)
1122 had_command_sigterm = sig;
1128 /*************************************************
1129 * Read one command line *
1130 *************************************************/
1132 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1133 There are sites that don't do this, and in any case internal SMTP probably
1134 should check only for LF. Consequently, we check here for LF only. The line
1135 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1136 an unknown command. The command is read into the global smtp_cmd_buffer so that
1137 it is available via $smtp_command.
1139 The character reading routine sets up a timeout for each block actually read
1140 from the input (which may contain more than one command). We set up a special
1141 signal handler that closes down the session on a timeout. Control does not
1142 return when it runs.
1145 check_sync if TRUE, check synchronization rules if global option is TRUE
1146 buffer_lim maximum to buffer in lower layer
1148 Returns: a code identifying the command (enumerated above)
1152 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1156 BOOL hadnull = FALSE;
1158 had_command_timeout = 0;
1159 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1161 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1163 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1165 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1173 smtp_cmd_buffer[ptr++] = c;
1176 receive_linecount++; /* For BSMTP errors */
1177 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1179 /* If hit end of file, return pseudo EOF command. Whether we have a
1180 part-line already read doesn't matter, since this is an error state. */
1182 if (c == EOF) return EOF_CMD;
1184 /* Remove any CR and white space at the end of the line, and terminate the
1187 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1188 smtp_cmd_buffer[ptr] = 0;
1190 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1192 /* NULLs are not allowed in SMTP commands */
1194 if (hadnull) return BADCHAR_CMD;
1196 /* Scan command list and return identity, having set the data pointer
1197 to the start of the actual data characters. Check for SMTP synchronization
1200 for (smtp_cmd_list * p = cmd_list; p < cmd_list + nelem(cmd_list); p++)
1202 #ifdef SUPPORT_PROXY
1203 /* Only allow QUIT command if Proxy Protocol parsing failed */
1204 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1208 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1209 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1210 || smtp_cmd_buffer[p->len] == 0
1211 || smtp_cmd_buffer[p->len] == ' '
1214 if ( smtp_inptr < smtp_inend /* Outstanding input */
1215 && p->cmd < sync_cmd_limit /* Command should sync */
1216 && check_sync /* Local flag set */
1217 && smtp_enforce_sync /* Global flag set */
1218 && sender_host_address != NULL /* Not local input */
1219 && !f.sender_host_notsocket /* Really is a socket */
1223 /* The variables $smtp_command and $smtp_command_argument point into the
1224 unmodified input buffer. A copy of the latter is taken for actual
1225 processing, so that it can be chopped up into separate parts if necessary,
1226 for example, when processing a MAIL command options such as SIZE that can
1227 follow the sender address. */
1229 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1230 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1231 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1232 smtp_cmd_data = smtp_data_buffer;
1234 /* Count non-mail commands from those hosts that are controlled in this
1235 way. The default is all hosts. We don't waste effort checking the list
1236 until we get a non-mail command, but then cache the result to save checking
1237 again. If there's a DEFER while checking the host, assume it's in the list.
1239 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1240 start of each incoming message by fiddling with the value in the table. */
1242 if (!p->is_mail_cmd)
1244 if (count_nonmail == TRUE_UNSET) count_nonmail =
1245 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1246 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1247 return TOO_MANY_NONMAIL_CMD;
1250 /* If there is data for a command that does not expect it, generate the
1253 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1257 #ifdef SUPPORT_PROXY
1258 /* Only allow QUIT command if Proxy Protocol parsing failed */
1259 if (proxy_session && f.proxy_session_failed)
1260 return PROXY_FAIL_IGNORE_CMD;
1263 /* Enforce synchronization for unknown commands */
1265 if ( smtp_inptr < smtp_inend /* Outstanding input */
1266 && check_sync /* Local flag set */
1267 && smtp_enforce_sync /* Global flag set */
1268 && sender_host_address /* Not local input */
1269 && !f.sender_host_notsocket /* Really is a socket */
1279 /*************************************************
1280 * Forced closedown of call *
1281 *************************************************/
1283 /* This function is called from log.c when Exim is dying because of a serious
1284 disaster, and also from some other places. If an incoming non-batched SMTP
1285 channel is open, it swallows the rest of the incoming message if in the DATA
1286 phase, sends the reply string, and gives an error to all subsequent commands
1287 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1291 message SMTP reply string to send, excluding the code
1297 smtp_closedown(uschar * message)
1299 if (!smtp_in || smtp_batched_input) return;
1300 receive_swallow_smtp();
1301 smtp_printf("421 %s\r\n", SP_NO_MORE, message);
1303 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1309 f.smtp_in_quit = TRUE;
1310 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
1315 smtp_printf("250 Reset OK\r\n", SP_NO_MORE);
1319 smtp_printf("421 %s\r\n", SP_NO_MORE, message);
1327 /*************************************************
1328 * Set up connection info for logging *
1329 *************************************************/
1331 /* This function is called when logging information about an SMTP connection.
1332 It sets up appropriate source information, depending on the type of connection.
1333 If sender_fullhost is NULL, we are at a very early stage of the connection;
1334 just use the IP address.
1337 Returns: a string describing the connection
1341 smtp_get_connection_info(void)
1343 const uschar * hostname = sender_fullhost
1344 ? sender_fullhost : sender_host_address;
1345 gstring * g = string_catn(NULL, US"SMTP connection", 15);
1347 if (LOGGING(connection_id))
1348 g = string_fmt_append(g, " Ci=%lu", connection_id);
1349 g = string_catn(g, US" from ", 6);
1352 g = string_cat(g, hostname);
1354 else if (f.sender_host_unknown || f.sender_host_notsocket)
1355 g = string_cat(g, sender_ident);
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 > 0 && recipients_count + 1 > recipients_max)
1880 /* The function moan_smtp_batch() does not return. */
1881 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1882 recipients_max_reject ? "552": "452");
1884 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1885 recipient address */
1887 recipient = rewrite_existflags & rewrite_smtp
1888 /* deconst ok as smtp_cmd_data was not const */
1889 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1890 global_rewrite_rules)
1893 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1894 &recipient_domain, FALSE);
1897 /* The function moan_smtp_batch() does not return. */
1898 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1900 /* If the recipient address is unqualified, qualify it if permitted. Then
1901 add it to the list of recipients. */
1903 if (!recipient_domain)
1904 if (f.allow_unqualified_recipient)
1906 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1908 /* deconst ok as recipient was not const */
1909 recipient = US rewrite_address_qualify(recipient, TRUE);
1911 /* The function moan_smtp_batch() does not return. */
1913 moan_smtp_batch(smtp_cmd_buffer,
1914 "501 recipient address must contain a domain");
1916 receive_add_recipient(recipient, -1);
1920 /* The DATA command is legal only if it follows successful MAIL FROM
1921 and RCPT TO commands. This function is complete when a valid DATA
1922 command is encountered. */
1925 if (!sender_address || recipients_count <= 0)
1926 /* The function moan_smtp_batch() does not return. */
1927 if (!sender_address)
1928 moan_smtp_batch(smtp_cmd_buffer,
1929 "503 MAIL FROM:<sender> command must precede DATA");
1931 moan_smtp_batch(smtp_cmd_buffer,
1932 "503 RCPT TO:<recipient> must precede DATA");
1935 done = 3; /* DATA successfully achieved */
1936 message_ended = END_NOTENDED; /* Indicate in middle of message */
1941 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1948 bsmtp_transaction_linecount = receive_linecount;
1953 f.smtp_in_quit = TRUE;
1960 /* The function moan_smtp_batch() does not return. */
1961 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1966 /* The function moan_smtp_batch() does not return. */
1967 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1972 /* The function moan_smtp_batch() does not return. */
1973 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1978 return done - 2; /* Convert yield values */
1986 smtp_log_tls_fail(const uschar * errstr)
1988 const uschar * conn_info = smtp_get_connection_info();
1990 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
1991 /* I'd like to get separated H= here, but too hard for now */
1993 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2007 socklen_t len = sizeof(is_fastopen);
2009 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2010 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2012 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2017 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2018 f.tcp_in_fastopen = TRUE;
2021 else DEBUG(D_receive)
2022 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2024 # elif defined(TCP_INFO)
2025 struct tcp_info tinfo;
2026 socklen_t len = sizeof(tinfo);
2028 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2029 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2030 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2033 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2034 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2038 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2041 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2042 f.tcp_in_fastopen = TRUE;
2044 else DEBUG(D_receive)
2045 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2052 log_connect_tls_drop(const uschar * what, const uschar * log_msg)
2054 if (log_reject_target)
2056 gstring * g = s_tlslog(NULL);
2057 uschar * tls = string_from_gstring(g);
2059 log_write(L_connection_reject,
2060 log_reject_target, "%s%s%s dropped by %s%s%s",
2061 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
2062 host_and_ident(TRUE),
2065 log_msg ? US": " : US"", log_msg);
2070 /*************************************************
2071 * Start an SMTP session *
2072 *************************************************/
2074 /* This function is called at the start of an SMTP session. Thereafter,
2075 smtp_setup_msg() is called to initiate each separate message. This
2076 function does host-specific testing, and outputs the banner line.
2079 Returns: FALSE if the session can not continue; something has
2080 gone wrong, or the connection to the host is blocked
2084 smtp_start_session(void)
2087 uschar *user_msg, *log_msg;
2092 gettimeofday(&smtp_connection_start, NULL);
2093 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2094 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2097 /* Default values for certain variables */
2099 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2100 smtp_mailcmd_count = 0;
2101 count_nonmail = TRUE_UNSET;
2102 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2103 smtp_delay_mail = smtp_rlm_base;
2104 fl.auth_advertised = FALSE;
2105 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2106 f.pipelining_enable = TRUE;
2107 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2108 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2110 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2111 authentication settings from -oMaa to remain in force. */
2113 if (!host_checking && !f.sender_host_notsocket)
2114 sender_host_auth_pubname = sender_host_authenticated = NULL;
2115 authenticated_by = NULL;
2118 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2119 tls_in.ourcert = tls_in.peercert = NULL;
2121 tls_in.ocsp = OCSP_NOT_REQ;
2122 fl.tls_advertised = FALSE;
2124 fl.dsn_advertised = FALSE;
2126 fl.smtputf8_advertised = FALSE;
2129 /* Reset ACL connection variables */
2133 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2135 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, GET_TAINTED);
2137 smtp_cmd_buffer[0] = 0;
2138 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2140 /* For batched input, the protocol setting can be overridden from the
2141 command line by a trusted caller. */
2143 if (smtp_batched_input)
2145 if (!received_protocol) received_protocol = US"local-bsmtp";
2148 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2149 reset later if any of EHLO/AUTH/STARTTLS are received. */
2153 (sender_host_address ? protocols : protocols_local) [pnormal];
2155 /* Set up the buffer for inputting using direct read() calls, and arrange to
2156 call the local functions instead of the standard C ones. */
2160 receive_getc = smtp_getc;
2161 receive_getbuf = smtp_getbuf;
2162 receive_get_cache = smtp_get_cache;
2163 receive_hasc = smtp_hasc;
2164 receive_ungetc = smtp_ungetc;
2165 receive_feof = smtp_feof;
2166 receive_ferror = smtp_ferror;
2167 lwr_receive_getc = NULL;
2168 lwr_receive_getbuf = NULL;
2169 lwr_receive_hasc = NULL;
2170 lwr_receive_ungetc = NULL;
2172 /* Set up the message size limit; this may be host-specific */
2174 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2175 if (expand_string_message)
2177 if (thismessage_size_limit == -1)
2178 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2179 "%s", expand_string_message);
2181 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2182 "%s", expand_string_message);
2183 smtp_closedown(US"Temporary local problem - please try later");
2187 /* When a message is input locally via the -bs or -bS options, sender_host_
2188 unknown is set unless -oMa was used to force an IP address, in which case it
2189 is checked like a real remote connection. When -bs is used from inetd, this
2190 flag is not set, causing the sending host to be checked. The code that deals
2191 with IP source routing (if configured) is never required for -bs or -bS and
2192 the flag sender_host_notsocket is used to suppress it.
2194 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2195 reserve for certain hosts and/or networks. */
2197 if (!f.sender_host_unknown)
2200 BOOL reserved_host = FALSE;
2202 /* Look up IP options (source routing info) on the socket if this is not an
2203 -oMa "host", and if any are found, log them and drop the connection.
2205 Linux (and others now, see below) is different to everyone else, so there
2206 has to be some conditional compilation here. Versions of Linux before 2.1.15
2207 used a structure whose name was "options". Somebody finally realized that
2208 this name was silly, and it got changed to "ip_options". I use the
2209 newer name here, but there is a fudge in the script that sets up os.h
2210 to define a macro in older Linux systems.
2212 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2213 glibc 2, which has chosen ip_opts for the structure name. This is now
2214 really a glibc thing rather than a Linux thing, so the condition name
2215 has been changed to reflect this. It is relevant also to GNU/Hurd.
2217 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2218 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2219 a special macro defined in the os.h file.
2221 Some DGUX versions on older hardware appear not to support IP options at
2222 all, so there is now a general macro which can be set to cut out this
2225 How to do this properly in IPv6 is not yet known. */
2227 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2229 # ifdef GLIBC_IP_OPTIONS
2230 # if (!defined __GLIBC__) || (__GLIBC__ < 2)
2235 # elif defined DARWIN_IP_OPTIONS
2241 if (!host_checking && !f.sender_host_notsocket)
2244 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2245 struct ip_options *ipopt = store_get(optlen, GET_UNTAINTED);
2246 # elif OPTSTYLE == 2
2247 struct ip_opts ipoptblock;
2248 struct ip_opts *ipopt = &ipoptblock;
2249 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2251 struct ipoption ipoptblock;
2252 struct ipoption *ipopt = &ipoptblock;
2253 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2256 /* Occasional genuine failures of getsockopt() have been seen - for
2257 example, "reset by peer". Therefore, just log and give up on this
2258 call, unless the error is ENOPROTOOPT. This error is given by systems
2259 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2260 of writing. So for that error, carry on - we just can't do an IP options
2263 DEBUG(D_receive) debug_printf("checking for IP options\n");
2265 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2268 if (errno != ENOPROTOOPT)
2270 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2271 host_and_ident(FALSE), strerror(errno));
2272 smtp_printf("451 SMTP service not available\r\n", SP_NO_MORE);
2277 /* Deal with any IP options that are set. On the systems I have looked at,
2278 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2279 more logging data than will fit in big_buffer. Nevertheless, after somebody
2280 questioned this code, I've added in some paranoid checking. */
2282 else if (optlen > 0)
2284 uschar * p = big_buffer;
2285 uschar * pend = big_buffer + big_buffer_size;
2288 struct in_addr addr;
2291 uschar * optstart = US (ipopt->__data);
2292 # elif OPTSTYLE == 2
2293 uschar * optstart = US (ipopt->ip_opts);
2295 uschar * optstart = US (ipopt->ipopt_list);
2298 DEBUG(D_receive) debug_printf("IP options exist\n");
2300 Ustrcpy(p, "IP options on incoming call:");
2303 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2318 string_format(p, pend-p, " %s [@%s",
2319 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2320 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr)))))
2321 # elif OPTSTYLE == 2
2322 string_format(p, pend-p, " %s [@%s",
2323 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2324 inet_ntoa(ipopt->ip_dst))
2326 string_format(p, pend-p, " %s [@%s",
2327 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2328 inet_ntoa(ipopt->ipopt_dst))
2337 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2339 while (optcount-- > 0)
2341 memcpy(&addr, adptr, sizeof(addr));
2342 if (!string_format(p, pend - p - 1, "%s%s",
2343 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2349 adptr += sizeof(struct in_addr);
2357 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2360 for (int i = 0; i < opt[1]; i++)
2361 p += sprintf(CS p, "%2.2x ", opt[i]);
2369 log_write(0, LOG_MAIN, "%s", big_buffer);
2371 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2373 log_write(0, LOG_MAIN|LOG_REJECT,
2374 "connection from %s refused (IP options)", host_and_ident(FALSE));
2376 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2380 /* Length of options = 0 => there are no options */
2382 else DEBUG(D_receive) debug_printf("no IP options found\n");
2384 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2386 /* Set keep-alive in socket options. The option is on by default. This
2387 setting is an attempt to get rid of some hanging connections that stick in
2388 read() when the remote end (usually a dialup) goes away. */
2390 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2391 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2393 /* If the current host matches host_lookup, set the name by doing a
2394 reverse lookup. On failure, sender_host_name will be NULL and
2395 host_lookup_failed will be TRUE. This may or may not be serious - optional
2398 if (verify_check_host(&host_lookup) == OK)
2400 (void)host_name_lookup();
2401 host_build_sender_fullhost();
2404 /* Delay this until we have the full name, if it is looked up. */
2406 set_process_info("handling incoming connection from %s",
2407 host_and_ident(FALSE));
2409 /* Expand smtp_receive_timeout, if needed */
2411 if (smtp_receive_timeout_s)
2414 if ( !(exp = expand_string(smtp_receive_timeout_s))
2416 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2418 log_write(0, LOG_MAIN|LOG_PANIC,
2419 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2422 /* Test for explicit connection rejection */
2424 if (verify_check_host(&host_reject_connection) == OK)
2426 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2427 "from %s (host_reject_connection)", host_and_ident(FALSE));
2429 if (!tls_in.on_connect)
2431 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2435 /* Test with TCP Wrappers if so configured. There is a problem in that
2436 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2437 such as disks dying. In these cases, it is desirable to reject with a 4xx
2438 error instead of a 5xx error. There isn't a "right" way to detect such
2439 problems. The following kludge is used: errno is zeroed before calling
2440 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2441 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2444 #ifdef USE_TCP_WRAPPERS
2446 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2447 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2448 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2449 expand_string_message);
2451 if (!hosts_ctl(tcp_wrappers_name,
2452 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2453 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2454 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2456 if (errno == 0 || errno == ENOENT)
2458 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2459 log_write(L_connection_reject,
2460 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2461 "(tcp wrappers)", host_and_ident(FALSE));
2462 smtp_printf("554 SMTP service not available\r\n", SP_NO_MORE);
2466 int save_errno = errno;
2467 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2468 "errno value %d\n", save_errno);
2469 log_write(L_connection_reject,
2470 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2471 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2472 smtp_printf("451 Temporary local problem - please try later\r\n", SP_NO_MORE);
2478 /* Check for reserved slots. The value of smtp_accept_count has already been
2479 incremented to include this process. */
2481 if (smtp_accept_max > 0 &&
2482 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2484 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2486 log_write(L_connection_reject,
2487 LOG_MAIN, "temporarily refused connection from %s: not in "
2488 "reserve list: connected=%d max=%d reserve=%d%s",
2489 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2490 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2491 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2492 "please try again later\r\n", SP_NO_MORE, smtp_active_hostname);
2495 reserved_host = TRUE;
2498 /* If a load level above which only messages from reserved hosts are
2499 accepted is set, check the load. For incoming calls via the daemon, the
2500 check is done in the superior process if there are no reserved hosts, to
2501 save a fork. In all cases, the load average will already be available
2502 in a global variable at this point. */
2504 if (smtp_load_reserve >= 0 &&
2505 load_average > smtp_load_reserve &&
2507 verify_check_host(&smtp_reserve_hosts) != OK)
2509 log_write(L_connection_reject,
2510 LOG_MAIN, "temporarily refused connection from %s: not in "
2511 "reserve list and load average = %.2f", host_and_ident(FALSE),
2512 (double)load_average/1000.0);
2513 smtp_printf("421 %s: Too much load; please try again later\r\n", SP_NO_MORE,
2514 smtp_active_hostname);
2518 /* Determine whether unqualified senders or recipients are permitted
2519 for this host. Unfortunately, we have to do this every time, in order to
2520 set the flags so that they can be inspected when considering qualifying
2521 addresses in the headers. For a site that permits no qualification, this
2522 won't take long, however. */
2524 f.allow_unqualified_sender =
2525 verify_check_host(&sender_unqualified_hosts) == OK;
2527 f.allow_unqualified_recipient =
2528 verify_check_host(&recipient_unqualified_hosts) == OK;
2530 /* Determine whether HELO/EHLO is required for this host. The requirement
2531 can be hard or soft. */
2533 fl.helo_verify_required = verify_check_host(&helo_verify_hosts) == OK;
2534 if (!fl.helo_verify_required)
2535 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2537 /* Determine whether this hosts is permitted to send syntactic junk
2538 after a HELO or EHLO command. */
2540 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2543 /* Expand recipients_max, if needed */
2545 uschar * rme = expand_string(recipients_max);
2546 recipients_max_expanded = atoi(CCS rme);
2548 /* For batch SMTP input we are now done. */
2550 if (smtp_batched_input) return TRUE;
2552 #if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS) || defined(EXPERIMETAL_XCLIENT)
2553 proxy_session = FALSE;
2556 #ifdef SUPPORT_PROXY
2557 /* If valid Proxy Protocol source is connecting, set up session.
2558 Failure will not allow any SMTP function other than QUIT. */
2560 f.proxy_session_failed = FALSE;
2561 if (proxy_protocol_host())
2563 os_non_restarting_signal(SIGALRM, command_timeout_handler);
2564 proxy_protocol_setup();
2568 /* Run the connect ACL if it exists */
2571 if (acl_smtp_connect)
2574 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2578 if (tls_in.on_connect)
2579 log_connect_tls_drop(US"'connect' ACL", log_msg);
2582 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2587 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2588 smtps port for use with older style SSL MTAs. */
2591 if (tls_in.on_connect)
2593 if (tls_server_start(&user_msg) != OK)
2594 return smtp_log_tls_fail(user_msg);
2595 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
2599 /* Output the initial message for a two-way SMTP connection. It may contain
2600 newlines, which then cause a multi-line response to be given. */
2602 code = US"220"; /* Default status code */
2603 esc = US""; /* Default extended status code */
2604 esclen = 0; /* Length of esc */
2610 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2614 esclen = codelen - 4;
2617 else if (!(s = expand_string(smtp_banner)))
2619 log_write(0, f.expand_string_forcedfail ? LOG_MAIN : LOG_MAIN|LOG_PANIC_DIE,
2620 "Expansion of \"%s\" (smtp_banner) failed: %s",
2621 smtp_banner, expand_string_message);
2622 /* for force-fail */
2624 if (tls_in.on_connect) tls_close(NULL, TLS_SHUTDOWN_WAIT);
2629 /* Remove any terminating newlines; might as well remove trailing space too */
2632 while (p > s && isspace(p[-1])) p--;
2633 s = string_copyn(s, p-s);
2635 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2636 is all contained in a single IP packet. The original code wrote out the
2637 greeting using several calls to fprint/fputc, and on busy servers this could
2638 cause it to be split over more than one packet - which caused CC:Mail to fall
2639 over when it got the second part of the greeting after sending its first
2640 command. Sigh. To try to avoid this, build the complete greeting message
2641 first, and output it in one fell swoop. This gives a better chance of it
2642 ending up as a single packet. */
2644 ss = string_get(256);
2647 do /* At least once, in case we have an empty string */
2650 uschar *linebreak = Ustrchr(p, '\n');
2651 ss = string_catn(ss, code, 3);
2655 ss = string_catn(ss, US" ", 1);
2659 len = linebreak - p;
2660 ss = string_catn(ss, US"-", 1);
2662 ss = string_catn(ss, esc, esclen);
2663 ss = string_catn(ss, p, len);
2664 ss = string_catn(ss, US"\r\n", 2);
2670 /* Before we write the banner, check that there is no input pending, unless
2671 this synchronisation check is disabled. */
2673 #ifndef DISABLE_PIPE_CONNECT
2674 fl.pipe_connect_acceptable =
2675 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
2678 if (fl.pipe_connect_acceptable)
2679 f.smtp_in_early_pipe_used = TRUE;
2685 unsigned n = smtp_inend - smtp_inptr;
2686 if (n > 128) n = 128;
2688 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2689 "synchronization error (input sent without waiting for greeting): "
2690 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2691 string_printing(string_copyn(smtp_inptr, n)));
2692 smtp_printf("554 SMTP synchronization error\r\n", SP_NO_MORE);
2696 /* Now output the banner */
2697 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
2700 #ifndef DISABLE_PIPE_CONNECT
2701 fl.pipe_connect_acceptable && pipeline_connect_sends(),
2707 /* Attempt to see if we sent the banner before the last ACK of the 3-way
2708 handshake arrived. If so we must have managed a TFO. */
2711 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
2721 /*************************************************
2722 * Handle SMTP syntax and protocol errors *
2723 *************************************************/
2725 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2726 to do so. Then transmit the error response. The return value depends on the
2727 number of syntax and protocol errors in this SMTP session.
2730 type error type, given as a log flag bit
2731 code response code; <= 0 means don't send a response
2732 data data to reflect in the response (can be NULL)
2733 errmess the error message
2735 Returns: -1 limit of syntax/protocol errors NOT exceeded
2736 +1 limit of syntax/protocol errors IS exceeded
2738 These values fit in with the values of the "done" variable in the main
2739 processing loop in smtp_setup_msg(). */
2742 synprot_error(int type, int code, uschar *data, uschar *errmess)
2746 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2747 type == L_smtp_syntax_error ? "syntax" : "protocol",
2748 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2750 if (++synprot_error_count > smtp_max_synprot_errors)
2753 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2754 "syntax or protocol errors (last command was \"%s\", %Y)",
2755 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
2762 smtp_printf("%d%c%s%s%s\r\n", SP_NO_MORE, code, yield == 1 ? '-' : ' ',
2763 data ? data : US"", data ? US": " : US"", errmess);
2765 smtp_printf("%d Too many syntax or protocol errors\r\n", SP_NO_MORE, code);
2774 /*************************************************
2775 * Send SMTP response, possibly multiline *
2776 *************************************************/
2778 /* There are, it seems, broken clients out there that cannot handle multiline
2779 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2780 output nothing for non-final calls, and only the first line for anything else.
2783 code SMTP code, may involve extended status codes
2784 codelen length of smtp code; if > 4 there's an ESC
2785 final FALSE if the last line isn't the final line
2786 msg message text, possibly containing newlines
2792 smtp_respond(uschar * code, int codelen, BOOL final, uschar * msg)
2797 if (!final && f.no_multiline_responses) return;
2802 esclen = codelen - 4;
2805 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2806 have had the same. Note: this code is also present in smtp_printf(). It would
2807 be tidier to have it only in one place, but when it was added, it was easier to
2808 do it that way, so as not to have to mess with the code for the RCPT command,
2809 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2811 if (fl.rcpt_in_progress)
2813 if (!rcpt_smtp_response)
2814 rcpt_smtp_response = string_copy(msg);
2815 else if (fl.rcpt_smtp_response_same &&
2816 Ustrcmp(rcpt_smtp_response, msg) != 0)
2817 fl.rcpt_smtp_response_same = FALSE;
2818 fl.rcpt_in_progress = FALSE;
2821 /* Now output the message, splitting it up into multiple lines if necessary.
2822 We only handle pipelining these responses as far as nonfinal/final groups,
2823 not the whole MAIL/RCPT/DATA response set. */
2827 uschar *nl = Ustrchr(msg, '\n');
2830 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
2833 else if (nl[1] == 0 || f.no_multiline_responses)
2835 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
2836 (int)(nl - msg), msg);
2841 smtp_printf("%.3s-%.*s%.*s\r\n", SP_MORE, code, esclen, esc, (int)(nl - msg), msg);
2843 Uskip_whitespace(&msg);
2851 /*************************************************
2852 * Parse user SMTP message *
2853 *************************************************/
2855 /* This function allows for user messages overriding the response code details
2856 by providing a suitable response code string at the start of the message
2857 user_msg. Check the message for starting with a response code and optionally an
2858 extended status code. If found, check that the first digit is valid, and if so,
2859 change the code pointer and length to use the replacement. An invalid code
2860 causes a panic log; in this case, if the log messages is the same as the user
2861 message, we must also adjust the value of the log message to show the code that
2862 is actually going to be used (the original one).
2864 This function is global because it is called from receive.c as well as within
2867 Note that the code length returned includes the terminating whitespace
2868 character, which is always included in the regex match.
2871 code SMTP code, may involve extended status codes
2872 codelen length of smtp code; if > 4 there's an ESC
2874 log_msg optional log message, to be adjusted with the new SMTP code
2875 check_valid if true, verify the response code
2881 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2887 if (!msg || !*msg || !regex_match(regex_smtp_code, *msg, -1, &match))
2890 len = Ustrlen(match);
2891 if (check_valid && (*msg)[0] != (*code)[0])
2893 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2894 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2895 if (log_msg && *log_msg == *msg)
2896 *log_msg = string_sprintf("%s %s", *code, *log_msg + len);
2901 *codelen = len; /* Includes final space */
2903 *msg += len; /* Chop the code off the message */
2910 /*************************************************
2911 * Handle an ACL failure *
2912 *************************************************/
2914 /* This function is called when acl_check() fails. As well as calls from within
2915 this module, it is called from receive.c for an ACL after DATA. It sorts out
2916 logging the incident, and sends the error response. A message containing
2917 newlines is turned into a multiline SMTP response, but for logging, only the
2920 There's a table of default permanent failure response codes to use in
2921 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2922 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2923 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2924 state, because there are broken clients that try VRFY before RCPT. A 5xx
2925 response should be given only when the address is positively known to be
2926 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2927 no explicit code, but if there is one we let it know best.
2928 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2930 From Exim 4.63, it is possible to override the response code details by
2931 providing a suitable response code string at the start of the message provided
2932 in user_msg. The code's first digit is checked for validity.
2935 where where the ACL was called from
2937 user_msg a message that can be included in an SMTP response
2938 log_msg a message for logging
2940 Returns: 0 in most cases
2941 2 if the failure code was FAIL_DROP, in which case the
2942 SMTP connection should be dropped (this value fits with the
2943 "done" variable in smtp_setup_msg() below)
2947 smtp_handle_acl_fail(int where, int rc, uschar * user_msg, uschar * log_msg)
2949 BOOL drop = rc == FAIL_DROP;
2953 uschar *sender_info = US"";
2956 if (drop) rc = FAIL;
2958 /* Set the default SMTP code, and allow a user message to change it. */
2960 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2961 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2962 where != ACL_WHERE_VRFY);
2964 /* We used to have sender_address here; however, there was a bug that was not
2965 updating sender_address after a rewrite during a verify. When this bug was
2966 fixed, sender_address at this point became the rewritten address. I'm not sure
2967 this is what should be logged, so I've changed to logging the unrewritten
2968 address to retain backward compatibility. */
2972 #ifdef WITH_CONTENT_SCAN
2973 case ACL_WHERE_MIME: what = US"during MIME ACL checks"; break;
2975 case ACL_WHERE_PREDATA: what = US"DATA"; break;
2976 case ACL_WHERE_DATA: what = US"after DATA"; break;
2977 #ifndef DISABLE_PRDR
2978 case ACL_WHERE_PRDR: what = US"after DATA PRDR"; break;
2982 uschar * place = smtp_cmd_data ? smtp_cmd_data : US"in \"connect\" ACL";
2985 if (where == ACL_WHERE_AUTH) /* avoid logging auth creds */
2988 for (s = smtp_cmd_data; *s && !isspace(*s); ) s++;
2989 lim = s - smtp_cmd_data; /* atop after method */
2991 what = string_sprintf("%s %.*s", acl_wherenames[where], lim, place);
2996 case ACL_WHERE_RCPT:
2997 case ACL_WHERE_DATA:
2998 #ifdef WITH_CONTENT_SCAN
2999 case ACL_WHERE_MIME:
3001 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3002 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3003 sender_host_authenticated ? US" A=" : US"",
3004 sender_host_authenticated ? sender_host_authenticated : US"",
3005 sender_host_authenticated && authenticated_id ? US":" : US"",
3006 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3011 /* If there's been a sender verification failure with a specific message, and
3012 we have not sent a response about it yet, do so now, as a preliminary line for
3013 failures, but not defers. However, always log it for defer, and log it for fail
3014 unless the sender_verify_fail log selector has been turned off. */
3016 if (sender_verified_failed &&
3017 !testflag(sender_verified_failed, af_sverify_told))
3019 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3020 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3022 setflag(sender_verified_failed, af_sverify_told);
3024 if (rc != FAIL || LOGGING(sender_verify_fail))
3025 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3026 host_and_ident(TRUE),
3027 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3028 sender_verified_failed->address,
3029 (sender_verified_failed->message == NULL)? US"" :
3030 string_sprintf(": %s", sender_verified_failed->message));
3032 if (rc == FAIL && sender_verified_failed->user_message)
3033 smtp_respond(smtp_code, codelen, SR_NOT_FINAL, string_sprintf(
3034 testflag(sender_verified_failed, af_verify_pmfail)?
3035 "Postmaster verification failed while checking <%s>\n%s\n"
3036 "Several RFCs state that you are required to have a postmaster\n"
3037 "mailbox for each mail domain. This host does not accept mail\n"
3038 "from domains whose servers reject the postmaster address."
3040 testflag(sender_verified_failed, af_verify_nsfail)?
3041 "Callback setup failed while verifying <%s>\n%s\n"
3042 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3043 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3044 "RFC requirements, and stops you from receiving standard bounce\n"
3045 "messages. This host does not accept mail from domains whose servers\n"
3048 "Verification failed for <%s>\n%s",
3049 sender_verified_failed->address,
3050 sender_verified_failed->user_message));
3052 fl.rcpt_in_progress = save_rcpt_in_progress;
3055 /* Sort out text for logging */
3057 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3058 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3060 /* Send permanent failure response to the command, but the code used isn't
3061 always a 5xx one - see comments at the start of this function. If the original
3062 rc was FAIL_DROP we drop the connection and yield 2. */
3065 smtp_respond(smtp_code, codelen, SR_FINAL,
3066 user_msg ? user_msg : US"Administrative prohibition");
3068 /* Send temporary failure response to the command. Don't give any details,
3069 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3070 verb, and for a header verify when smtp_return_error_details is set.
3072 This conditional logic is all somewhat of a mess because of the odd
3073 interactions between temp_details and return_error_details. One day it should
3074 be re-implemented in a tidier fashion. */
3077 if (f.acl_temp_details && user_msg)
3079 if ( smtp_return_error_details
3080 && sender_verified_failed
3081 && sender_verified_failed->message
3083 smtp_respond(smtp_code, codelen, SR_NOT_FINAL, sender_verified_failed->message);
3085 smtp_respond(smtp_code, codelen, SR_FINAL, user_msg);
3088 smtp_respond(smtp_code, codelen, SR_FINAL,
3089 US"Temporary local problem - please try later");
3091 /* Log the incident to the logs that are specified by log_reject_target
3092 (default main, reject). This can be empty to suppress logging of rejections. If
3093 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3094 is closing if required and return 2. */
3096 if (log_reject_target)
3099 gstring * g = s_tlslog(NULL);
3100 uschar * tls = string_from_gstring(g);
3101 if (!tls) tls = US"";
3103 uschar * tls = US"";
3105 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3106 log_reject_target, "%s%s%s %s%srejected %s%s",
3107 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3108 host_and_ident(TRUE),
3111 rc == FAIL ? US"" : US"temporarily ",
3115 if (!drop) return 0;
3117 log_close_event(US"by DROP in ACL");
3119 /* Run the not-quit ACL, but without any custom messages. This should not be a
3120 problem, because we get here only if some other ACL has issued "drop", and
3121 in that case, *its* custom messages will have been used above. */
3123 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3125 /* An overenthusiastic fail2ban/iptables implimentation has been seen to result
3126 in the TCP conn staying open, and retrying, despite this process exiting. A
3127 malicious client could possibly do the same, tying up server netowrking
3128 resources. Close the socket explicitly to try to avoid that (there's a note in
3129 the Linux socket(7) manpage, SO_LINGER para, to the effect that exim() without
3130 close() results in the socket always lingering). */
3132 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3133 DEBUG(D_any) debug_printf_indent("SMTP(close)>>\n");
3134 (void) fclose(smtp_in);
3135 (void) fclose(smtp_out);
3143 /*************************************************
3144 * Handle SMTP exit when QUIT is not given *
3145 *************************************************/
3147 /* This function provides a logging/statistics hook for when an SMTP connection
3148 is dropped on the floor or the other end goes away. It's a global function
3149 because it's called from receive.c as well as this module. As well as running
3150 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3151 response, either with a custom message from the ACL, or using a default. There
3152 is one case, however, when no message is output - after "drop". In that case,
3153 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3154 passed to this function.
3156 In case things go wrong while processing this function, causing an error that
3157 may re-enter this function, there is a recursion check.
3160 reason What $smtp_notquit_reason will be set to in the ACL;
3161 if NULL, the ACL is not run
3162 code The error code to return as part of the response
3163 defaultrespond The default message if there's no user_msg
3169 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3172 uschar *user_msg = NULL;
3173 uschar *log_msg = NULL;
3175 /* Check for recursive call */
3177 if (fl.smtp_exit_function_called)
3179 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3183 fl.smtp_exit_function_called = TRUE;
3185 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3187 if (acl_smtp_notquit && reason)
3189 smtp_notquit_reason = reason;
3190 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3191 &log_msg)) == ERROR)
3192 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3196 /* If the connection was dropped, we certainly are no longer talking TLS */
3197 tls_in.active.sock = -1;
3199 /* Write an SMTP response if we are expected to give one. As the default
3200 responses are all internal, they should be reasonable size. */
3202 if (code && defaultrespond)
3205 smtp_respond(code, 3, SR_FINAL, user_msg);
3211 va_start(ap, defaultrespond);
3212 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3214 smtp_printf("%s %Y\r\n", SP_NO_MORE, code, g);
3223 /*************************************************
3224 * Verify HELO argument *
3225 *************************************************/
3227 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3228 matched. It is also called from ACL processing if verify = helo is used and
3229 verification was not previously tried (i.e. helo_try_verify_hosts was not
3230 matched). The result of its processing is to set helo_verified and
3231 helo_verify_failed. These variables should both be FALSE for this function to
3234 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3235 for IPv6 ::ffff: literals.
3238 Returns: TRUE if testing was completed;
3239 FALSE on a temporary failure
3243 smtp_verify_helo(void)
3247 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3250 if (sender_helo_name == NULL)
3252 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3255 /* Deal with the case of -bs without an IP address */
3257 else if (sender_host_address == NULL)
3259 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3260 f.helo_verified = TRUE;
3263 /* Deal with the more common case when there is a sending IP address */
3265 else if (sender_helo_name[0] == '[')
3267 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3268 Ustrlen(sender_host_address)) == 0;
3271 if (!f.helo_verified)
3273 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3274 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3275 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3280 { if (f.helo_verified) debug_printf("matched host address\n"); }
3283 /* Do a reverse lookup if one hasn't already given a positive or negative
3284 response. If that fails, or the name doesn't match, try checking with a forward
3289 if (sender_host_name == NULL && !host_lookup_failed)
3290 yield = host_name_lookup() != DEFER;
3292 /* If a host name is known, check it and all its aliases. */
3294 if (sender_host_name)
3295 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3297 sender_helo_dnssec = sender_host_dnssec;
3298 HDEBUG(D_receive) debug_printf("matched host name\n");
3302 uschar **aliases = sender_host_aliases;
3304 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3306 sender_helo_dnssec = sender_host_dnssec;
3310 HDEBUG(D_receive) if (f.helo_verified)
3311 debug_printf("matched alias %s\n", *(--aliases));
3314 /* Final attempt: try a forward lookup of the helo name */
3316 if (!f.helo_verified)
3320 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3322 {.request = US"*", .require = US""};
3324 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3326 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3327 NULL, NULL, NULL, &d, NULL, NULL);
3328 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3329 for (host_item * hh = &h; hh; hh = hh->next)
3330 if (Ustrcmp(hh->address, sender_host_address) == 0)
3332 f.helo_verified = TRUE;
3333 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3335 debug_printf("IP address for %s matches calling address\n"
3336 "Forward DNS security status: %sverified\n",
3337 sender_helo_name, sender_helo_dnssec ? "" : "un");
3343 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3350 /*************************************************
3351 * Send user response message *
3352 *************************************************/
3354 /* This function is passed a default response code and a user message. It calls
3355 smtp_message_code() to check and possibly modify the response code, and then
3356 calls smtp_respond() to transmit the response. I put this into a function
3357 just to avoid a lot of repetition.
3360 code the response code
3361 user_msg the user message
3367 smtp_user_msg(uschar *code, uschar *user_msg)
3370 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3371 smtp_respond(code, len, SR_FINAL, user_msg);
3377 smtp_in_auth(auth_instance *au, uschar ** smtp_resp, uschar ** errmsg)
3379 const uschar *set_id = NULL;
3382 /* Set up globals for error messages */
3384 authenticator_name = au->name;
3385 driver_srcfile = au->srcfile;
3386 driver_srcline = au->srcline;
3388 /* Run the checking code, passing the remainder of the command line as
3389 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3390 it as the only set numerical variable. The authenticator may set $auth<n>
3391 and also set other numeric variables. The $auth<n> variables are preferred
3392 nowadays; the numerical variables remain for backwards compatibility.
3394 Afterwards, have a go at expanding the set_id string, even if
3395 authentication failed - for bad passwords it can be useful to log the
3396 userid. On success, require set_id to expand and exist, and put it in
3397 authenticated_id. Save this in permanent store, as the working store gets
3398 reset at HELO, RSET, etc. */
3400 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3402 expand_nlength[0] = 0; /* $0 contains nothing */
3404 rc = (au->info->servercode)(au, smtp_cmd_data);
3405 if (au->set_id) set_id = expand_string(au->set_id);
3406 expand_nmax = -1; /* Reset numeric variables */
3407 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3408 driver_srcfile = authenticator_name = NULL; driver_srcline = 0;
3410 /* The value of authenticated_id is stored in the spool file and printed in
3411 log lines. It must not contain binary zeros or newline characters. In
3412 normal use, it never will, but when playing around or testing, this error
3413 can (did) happen. To guard against this, ensure that the id contains only
3414 printing characters. */
3416 if (set_id) set_id = string_printing(set_id);
3418 /* For the non-OK cases, set up additional logging data if set_id
3422 set_id = set_id && *set_id
3423 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3425 /* Switch on the result */
3430 if (!au->set_id || set_id) /* Complete success */
3432 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3433 sender_host_authenticated = au->name;
3434 sender_host_auth_pubname = au->public_name;
3435 authentication_failed = FALSE;
3436 authenticated_fail_id = NULL; /* Impossible to already be set? */
3439 (sender_host_address ? protocols : protocols_local)
3440 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3441 *smtp_resp = *errmsg = US"235 Authentication succeeded";
3442 authenticated_by = au;
3446 /* Authentication succeeded, but we failed to expand the set_id string.
3447 Treat this as a temporary error. */
3449 auth_defer_msg = expand_string_message;
3453 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3454 *smtp_resp = string_sprintf("435 Unable to authenticate at present%s",
3455 auth_defer_user_msg);
3456 *errmsg = string_sprintf("435 Unable to authenticate at present%s: %s",
3457 set_id, auth_defer_msg);
3461 *smtp_resp = *errmsg = US"501 Invalid base64 data";
3465 *smtp_resp = *errmsg = US"501 Authentication cancelled";
3469 *smtp_resp = *errmsg = US"553 Initial data not expected";
3473 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3474 *smtp_resp = US"535 Incorrect authentication data";
3475 *errmsg = string_sprintf("535 Incorrect authentication data%s", set_id);
3479 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3480 *smtp_resp = US"435 Internal error";
3481 *errmsg = string_sprintf("435 Internal error%s: return %d from authentication "
3482 "check", set_id, rc);
3494 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3497 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3499 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3501 rd = Ustrlen(recipient) + 1;
3502 /* deconst ok as *recipient was not const */
3503 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3506 smtp_printf("501 %s: recipient address must contain a domain\r\n", SP_NO_MORE,
3508 log_write(L_smtp_syntax_error,
3509 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3510 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3518 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3521 f.smtp_in_quit = TRUE;
3522 incomplete_transaction_log(US"QUIT");
3524 && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp)
3526 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3529 #ifdef EXIM_TCP_CORK
3530 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
3534 smtp_respond(US"221", 3, SR_FINAL, *user_msgp);
3536 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
3538 #ifdef SERVERSIDE_CLOSE_NOWAIT
3539 # ifndef DISABLE_TLS
3540 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3543 log_close_event(US"by QUIT");
3546 # ifndef DISABLE_TLS
3547 tls_close(NULL, TLS_SHUTDOWN_WAIT);
3550 log_close_event(US"by QUIT");
3552 /* Pause, hoping client will FIN first so that they get the TIME_WAIT.
3553 The socket should become readble (though with no data) */
3555 (void) poll_one_fd(fileno(smtp_in), POLLIN, 200);
3556 #endif /*!SERVERSIDE_CLOSE_NOWAIT*/
3561 smtp_rset_handler(void)
3564 incomplete_transaction_log(US"RSET");
3565 smtp_printf("250 Reset OK\r\n", SP_NO_MORE);
3566 cmd_list[CL_RSET].is_mail_cmd = FALSE;
3567 if (chunking_state > CHUNKING_OFFERED)
3568 chunking_state = CHUNKING_OFFERED;
3573 expand_mailmax(const uschar * s)
3575 if (!(s = expand_cstring(s)))
3576 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand smtp_accept_max_per_connection");
3577 return *s ? Uatoi(s) : 0;
3580 /*************************************************
3581 * Initialize for SMTP incoming message *
3582 *************************************************/
3584 /* This function conducts the initial dialogue at the start of an incoming SMTP
3585 message, and builds a list of recipients. However, if the incoming message
3586 is part of a batch (-bS option) a separate function is called since it would
3587 be messy having tests splattered about all over this function. This function
3588 therefore handles the case where interaction is occurring. The input and output
3589 files are set up in smtp_in and smtp_out.
3591 The global recipients_list is set to point to a vector of recipient_item
3592 blocks, whose number is given by recipients_count. This is extended by the
3593 receive_add_recipient() function. The global variable sender_address is set to
3594 the sender's address. The yield is +1 if a message has been successfully
3595 started, 0 if a QUIT command was encountered or the connection was refused from
3596 the particular host, or -1 if the connection was lost.
3600 Returns: > 0 message successfully started (reached DATA)
3601 = 0 QUIT read or end of file reached or call refused
3606 smtp_setup_msg(void)
3609 BOOL toomany = FALSE;
3610 BOOL discarded = FALSE;
3611 BOOL last_was_rej_mail = FALSE;
3612 BOOL last_was_rcpt = FALSE;
3613 rmark reset_point = store_mark();
3615 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3617 /* Reset for start of new message. We allow one RSET not to be counted as a
3618 nonmail command, for those MTAs that insist on sending it between every
3619 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3620 TLS between messages (an Exim client may do this if it has messages queued up
3621 for the host). Note: we do NOT reset AUTH at this point. */
3623 reset_point = smtp_reset(reset_point);
3624 message_ended = END_NOTSTARTED;
3626 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3628 cmd_list[CL_RSET].is_mail_cmd = TRUE;
3629 cmd_list[CL_HELO].is_mail_cmd = TRUE;
3630 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
3632 cmd_list[CL_STLS].is_mail_cmd = TRUE;
3635 if (lwr_receive_getc != NULL)
3637 /* This should have already happened, but if we've gotten confused,
3638 force a reset here. */
3639 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
3640 bdat_pop_receive_functions();
3643 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3645 had_command_sigterm = 0;
3646 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3648 /* Batched SMTP is handled in a different function. */
3650 if (smtp_batched_input) return smtp_setup_batch_msg();
3653 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3654 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3655 US &off, sizeof(off));
3658 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3659 value. The values are 2 larger than the required yield of the function. */
3663 const uschar **argv;
3664 uschar *etrn_command;
3665 uschar *etrn_serialize_key;
3667 uschar *log_msg, *smtp_code;
3668 uschar *user_msg = NULL;
3669 uschar *recipient = NULL;
3670 uschar *hello = NULL;
3672 BOOL was_rej_mail = FALSE;
3673 BOOL was_rcpt = FALSE;
3674 void (*oldsignal)(int);
3676 int start, end, sender_domain, recipient_domain;
3679 uschar *orcpt = NULL;
3684 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3685 if ( tls_in.active.sock >= 0
3687 && tls_in.certificate_verified
3688 && cmd_list[CL_TLAU].is_mail_cmd
3691 cmd_list[CL_TLAU].is_mail_cmd = FALSE;
3693 for (auth_instance * au = auths; au; au = au->next)
3694 if (strcmpic(US"tls", au->driver_name) == 0)
3697 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3698 &user_msg, &log_msg)) != OK
3700 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3703 smtp_cmd_data = NULL;
3705 if (smtp_in_auth(au, &s, &ss) == OK)
3706 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3709 DEBUG(D_auth) debug_printf("tls auth not succeeded\n");
3710 #ifndef DISABLE_EVENT
3712 uschar * save_name = sender_host_authenticated, * logmsg;
3713 sender_host_authenticated = au->name;
3714 if ((logmsg = event_raise(event_action, US"auth:fail", s, NULL)))
3715 log_write(0, LOG_MAIN, "%s", logmsg);
3716 sender_host_authenticated = save_name;
3726 switch(smtp_read_command(
3727 #ifndef DISABLE_PIPE_CONNECT
3728 !fl.pipe_connect_acceptable,
3732 GETC_BUFFER_UNLIMITED))
3734 /* The AUTH command is not permitted to occur inside a transaction, and may
3735 occur successfully only once per connection. Actually, that isn't quite
3736 true. When TLS is started, all previous information about a connection must
3737 be discarded, so a new AUTH is permitted at that time.
3739 AUTH may only be used when it has been advertised. However, it seems that
3740 there are clients that send AUTH when it hasn't been advertised, some of
3741 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3742 So there's a get-out that allows this to happen.
3744 AUTH is initially labelled as a "nonmail command" so that one occurrence
3745 doesn't get counted. We change the label here so that multiple failing
3746 AUTHS will eventually hit the nonmail threshold. */
3750 authentication_failed = TRUE;
3751 cmd_list[CL_AUTH].is_mail_cmd = FALSE;
3753 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
3755 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3756 US"AUTH command used when not advertised");
3759 if (sender_host_authenticated)
3761 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3762 US"already authenticated");
3767 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3768 US"not permitted in mail transaction");
3775 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3776 &user_msg, &log_msg)) != OK
3779 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3783 /* Find the name of the requested authentication mechanism. */
3786 for (; (c = *smtp_cmd_data) && !isspace(c); smtp_cmd_data++)
3787 if (!isalnum(c) && c != '-' && c != '_')
3789 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3790 US"invalid character in authentication mechanism name");
3794 /* If not at the end of the line, we must be at white space. Terminate the
3795 name and move the pointer on to any data that may be present. */
3799 *smtp_cmd_data++ = 0;
3800 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3803 /* Search for an authentication mechanism which is configured for use
3804 as a server and which has been advertised (unless, sigh, allow_auth_
3805 unadvertised is set). */
3809 uschar * smtp_resp, * errmsg;
3811 for (au = auths; au; au = au->next)
3812 if (strcmpic(s, au->public_name) == 0 && au->server &&
3813 (au->advertised || f.allow_auth_unadvertised))
3818 int rc = smtp_in_auth(au, &smtp_resp, &errmsg);
3820 smtp_printf("%s\r\n", SP_NO_MORE, smtp_resp);
3823 uschar * logmsg = NULL;
3824 #ifndef DISABLE_EVENT
3825 {uschar * save_name = sender_host_authenticated;
3826 sender_host_authenticated = au->name;
3827 logmsg = event_raise(event_action, US"auth:fail", smtp_resp, NULL);
3828 sender_host_authenticated = save_name;
3832 log_write(0, LOG_MAIN|LOG_REJECT, "%s", logmsg);
3834 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3835 au->name, host_and_ident(FALSE), errmsg);
3839 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3840 string_sprintf("%s authentication mechanism not supported", s));
3843 break; /* AUTH_CMD */
3845 /* The HELO/EHLO commands are permitted to appear in the middle of a
3846 session as well as at the beginning. They have the effect of a reset in
3847 addition to their other functions. Their absence at the start cannot be
3848 taken to be an error.
3852 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3853 or 502 failure replies MUST be returned as appropriate. The SMTP
3854 server MUST stay in the same state after transmitting these replies
3855 that it was in before the EHLO was received.
3857 Therefore, we do not do the reset until after checking the command for
3858 acceptability. This change was made for Exim release 4.11. Previously
3859 it did the reset first. */
3872 HELO_EHLO: /* Common code for HELO and EHLO */
3873 cmd_list[CL_HELO].is_mail_cmd = FALSE;
3874 cmd_list[CL_EHLO].is_mail_cmd = FALSE;
3876 /* Reject the HELO if its argument was invalid or non-existent. A
3877 successful check causes the argument to be saved in malloc store. */
3879 if (!check_helo(smtp_cmd_data))
3881 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", SP_NO_MORE, hello);
3883 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3884 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3885 *smtp_cmd_argument == 0 ? US"(no argument given)" :
3886 string_printing(smtp_cmd_argument));
3888 if (++synprot_error_count > smtp_max_synprot_errors)
3890 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3891 "syntax or protocol errors (last command was \"%s\", %Y)",
3892 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3901 /* If sender_host_unknown is true, we have got here via the -bs interface,
3902 not called from inetd. Otherwise, we are running an IP connection and the
3903 host address will be set. If the helo name is the primary name of this
3904 host and we haven't done a reverse lookup, force one now. If helo_verify_required
3905 is set, ensure that the HELO name matches the actual host. If helo_verify
3906 is set, do the same check, but softly. */
3908 if (!f.sender_host_unknown)
3910 BOOL old_helo_verified = f.helo_verified;
3911 uschar *p = smtp_cmd_data;
3913 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3916 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3917 because otherwise the log can be confusing. */
3919 if ( !sender_host_name
3920 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3921 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
3922 (void)host_name_lookup();
3924 /* Rebuild the fullhost info to include the HELO name (and the real name
3925 if it was looked up.) */
3927 host_build_sender_fullhost(); /* Rebuild */
3928 set_process_info("handling%s incoming connection from %s",
3929 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
3931 /* Verify if configured. This doesn't give much security, but it does
3932 make some people happy to be able to do it. If helo_verify_required is set,
3933 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3934 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3935 now obsolescent, since the verification can now be requested selectively
3938 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
3939 if (fl.helo_verify_required || fl.helo_verify)
3941 BOOL tempfail = !smtp_verify_helo();
3942 if (!f.helo_verified)
3944 if (fl.helo_verify_required)
3946 smtp_printf("%d %s argument does not match calling host\r\n", SP_NO_MORE,
3947 tempfail? 451 : 550, hello);
3948 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3949 tempfail? "temporarily " : "",
3950 hello, sender_helo_name, host_and_ident(FALSE));
3951 f.helo_verified = old_helo_verified;
3952 break; /* End of HELO/EHLO processing */
3954 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3955 "helo_try_verify_hosts\n", hello);
3961 /* set up SPF context */
3962 spf_conn_init(sender_helo_name, sender_host_address);
3965 /* Apply an ACL check if one is defined; afterwards, recheck
3966 synchronization in case the client started sending in a delay. */
3969 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3970 &user_msg, &log_msg)) != OK)
3972 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3973 sender_helo_name = NULL;
3974 host_build_sender_fullhost(); /* Rebuild */
3977 #ifndef DISABLE_PIPE_CONNECT
3978 else if (!fl.pipe_connect_acceptable && !check_sync())
3980 else if (!check_sync())
3984 /* Generate an OK reply. The default string includes the ident if present,
3985 and also the IP address if present. Reflecting back the ident is intended
3986 as a deterrent to mail forgers. For maximum efficiency, and also because
3987 some broken systems expect each response to be in a single packet, arrange
3988 that the entire reply is sent in one write(). */
3990 fl.auth_advertised = FALSE;
3991 f.smtp_in_pipelining_advertised = FALSE;
3993 fl.tls_advertised = FALSE;
3995 fl.dsn_advertised = FALSE;
3997 fl.smtputf8_advertised = FALSE;
4000 /* Expand the per-connection message count limit option */
4001 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4003 smtp_code = US"250 "; /* Default response code plus space*/
4006 /* sender_host_name below will be tainted, so save on copy when we hit it */
4007 g = string_get_tainted(24, GET_TAINTED);
4008 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4010 smtp_active_hostname,
4011 sender_ident ? sender_ident : US"",
4012 sender_ident ? US" at " : US"",
4013 sender_host_name ? sender_host_name : sender_helo_name);
4015 if (sender_host_address)
4016 g = string_fmt_append(g, " [%s]", sender_host_address);
4019 /* A user-supplied EHLO greeting may not contain more than one line. Note
4020 that the code returned by smtp_message_code() includes the terminating
4021 whitespace character. */
4027 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4028 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4029 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4031 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4032 "newlines: message truncated: %s", string_printing(s));
4035 g = string_cat(NULL, s);
4038 g = string_catn(g, US"\r\n", 2);
4040 /* If we received EHLO, we must create a multiline response which includes
4041 the functions supported. */
4045 g->s[3] = '-'; /* overwrite the space after the SMTP response code */
4047 /* I'm not entirely happy with this, as an MTA is supposed to check
4048 that it has enough room to accept a message of maximum size before
4049 it sends this. However, there seems little point in not sending it.
4050 The actual size check happens later at MAIL FROM time. By postponing it
4051 till then, VRFY and EXPN can be used after EHLO when space is short. */
4053 if (thismessage_size_limit > 0)
4054 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4055 thismessage_size_limit);
4058 g = string_catn(g, smtp_code, 3);
4059 g = string_catn(g, US"-SIZE\r\n", 7);
4062 #ifndef DISABLE_ESMTP_LIMITS
4063 if ( (smtp_mailcmd_max > 0 || recipients_max_expanded > 0)
4064 && verify_check_host(&limits_advertise_hosts) == OK)
4066 g = string_fmt_append(g, "%.3s-LIMITS", smtp_code);
4067 if (smtp_mailcmd_max > 0)
4068 g = string_fmt_append(g, " MAILMAX=%d", smtp_mailcmd_max);
4069 if (recipients_max > 9)
4070 g = string_fmt_append(g, " RCPTMAX=%d", recipients_max_expanded);
4071 g = string_catn(g, US"\r\n", 2);
4075 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4076 clean; if it has an 8-bit character in its hand, it just sends it. It
4077 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4078 However, some users want this option simply in order to stop MUAs
4079 mangling messages that contain top-bit-set characters. It is therefore
4080 provided as an option. */
4082 if (accept_8bitmime)
4084 g = string_catn(g, smtp_code, 3);
4085 g = string_catn(g, US"-8BITMIME\r\n", 11);
4088 /* Advertise DSN support if configured to do so. */
4089 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4091 g = string_catn(g, smtp_code, 3);
4092 g = string_catn(g, US"-DSN\r\n", 6);
4093 fl.dsn_advertised = TRUE;
4096 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4097 permitted to issue them; a check is made when any host actually tries. */
4101 g = string_catn(g, smtp_code, 3);
4102 g = string_catn(g, US"-ETRN\r\n", 7);
4106 g = string_catn(g, smtp_code, 3);
4107 g = string_catn(g, US"-VRFY\r\n", 7);
4111 g = string_catn(g, smtp_code, 3);
4112 g = string_catn(g, US"-EXPN\r\n", 7);
4115 /* Exim is quite happy with pipelining, so let the other end know that
4116 it is safe to use it, unless advertising is disabled. */
4118 if ( f.pipelining_enable
4119 && verify_check_host(&pipelining_advertise_hosts) == OK)
4121 g = string_catn(g, smtp_code, 3);
4122 g = string_catn(g, US"-PIPELINING\r\n", 13);
4123 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4124 f.smtp_in_pipelining_advertised = TRUE;
4126 #ifndef DISABLE_PIPE_CONNECT
4127 if (fl.pipe_connect_acceptable)
4129 f.smtp_in_early_pipe_advertised = TRUE;
4130 g = string_catn(g, smtp_code, 3);
4131 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4137 /* If any server authentication mechanisms are configured, advertise
4138 them if the current host is in auth_advertise_hosts. The problem with
4139 advertising always is that some clients then require users to
4140 authenticate (and aren't configurable otherwise) even though it may not
4141 be necessary (e.g. if the host is in host_accept_relay).
4143 RFC 2222 states that SASL mechanism names contain only upper case
4144 letters, so output the names in upper case, though we actually recognize
4145 them in either case in the AUTH command. */
4149 && !sender_host_authenticated
4151 && verify_check_host(&auth_advertise_hosts) == OK
4155 for (auth_instance * au = auths; au; au = au->next)
4157 au->advertised = FALSE;
4160 DEBUG(D_auth+D_expand) debug_printf_indent(
4161 "Evaluating advertise_condition for %s %s athenticator\n",
4162 au->name, au->public_name);
4163 if ( !au->advertise_condition
4164 || expand_check_condition(au->advertise_condition, au->name,
4171 g = string_catn(g, smtp_code, 3);
4172 g = string_catn(g, US"-AUTH", 5);
4174 fl.auth_advertised = TRUE;
4176 saveptr = gstring_length(g);
4177 g = string_catn(g, US" ", 1);
4178 g = string_cat(g, au->public_name);
4179 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4180 au->advertised = TRUE;
4185 if (!first) g = string_catn(g, US"\r\n", 2);
4188 /* RFC 3030 CHUNKING */
4190 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4192 g = string_catn(g, smtp_code, 3);
4193 g = string_catn(g, US"-CHUNKING\r\n", 11);
4194 f.chunking_offered = TRUE;
4195 chunking_state = CHUNKING_OFFERED;
4198 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4199 if it has been included in the binary, and the host matches
4200 tls_advertise_hosts. We must *not* advertise if we are already in a
4201 secure connection. */
4204 if (tls_in.active.sock < 0 &&
4205 verify_check_host(&tls_advertise_hosts) != FAIL)
4207 g = string_catn(g, smtp_code, 3);
4208 g = string_catn(g, US"-STARTTLS\r\n", 11);
4209 fl.tls_advertised = TRUE;
4212 #ifdef EXPERIMENTAL_XCLIENT
4213 if (proxy_session || verify_check_host(&hosts_xclient) != FAIL)
4215 g = string_catn(g, smtp_code, 3);
4216 g = xclient_smtp_advertise_str(g);
4219 #ifndef DISABLE_PRDR
4220 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4223 g = string_catn(g, smtp_code, 3);
4224 g = string_catn(g, US"-PRDR\r\n", 7);
4229 if ( accept_8bitmime
4230 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4232 g = string_catn(g, smtp_code, 3);
4233 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4234 fl.smtputf8_advertised = TRUE;
4238 /* Finish off the multiline reply with one that is always available. */
4240 g = string_catn(g, smtp_code, 3);
4241 g = string_catn(g, US" HELP\r\n", 7);
4244 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4249 int len = len_string_from_gstring(g, &ehlo_resp);
4251 if (tls_in.active.sock >= 0)
4252 (void) tls_write(NULL, ehlo_resp, len,
4253 # ifndef DISABLE_PIPE_CONNECT
4254 fl.pipe_connect_acceptable && pipeline_connect_sends());
4260 (void) fwrite(ehlo_resp, 1, len, smtp_out);
4262 DEBUG(D_receive) for (const uschar * t, * s = ehlo_resp;
4263 s && (t = Ustrchr(s, '\r'));
4264 s = t + 2) /* \r\n */
4265 debug_printf("%s %.*s\n",
4266 s == g->s ? "SMTP>>" : " ",
4268 fl.helo_seen = TRUE;
4271 /* Reset the protocol and the state, abandoning any previous message. */
4273 (sender_host_address ? protocols : protocols_local)
4275 ? pextend + (sender_host_authenticated ? pauthed : 0)
4277 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4279 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4280 reset_point = smtp_reset(reset_point);
4282 break; /* HELO/EHLO */
4284 #ifdef EXPERIMENTAL_XCLIENT
4287 BOOL fatal = fl.helo_seen;
4292 smtp_mailcmd_count++;
4294 if ((errmsg = xclient_smtp_command(smtp_cmd_data, &resp, &fatal)))
4296 done = synprot_error(L_smtp_syntax_error, resp, NULL, errmsg);
4299 smtp_printf("%d %s\r\n", SP_NO_MORE, resp, errmsg);
4300 log_write(0, LOG_MAIN|LOG_REJECT, "rejected XCLIENT from %s: %s",
4301 host_and_ident(FALSE), errmsg);
4305 fl.helo_seen = FALSE; /* Require another EHLO */
4306 smtp_code = string_sprintf("%d", resp);
4308 /*XXX unclear in spec. if this needs to be an ESMTP banner,
4309 nor whether we get the original client's HELO after (or a proxy fake).
4310 We require that we do; the following HELO/EHLO handling will set
4311 sender_helo_name as normal. */
4313 smtp_printf("%s XCLIENT success\r\n", SP_NO_MORE, smtp_code);
4315 break; /* XCLIENT */
4320 /* The MAIL command requires an address as an operand. All we do
4321 here is to parse it for syntactic correctness. The form "<>" is
4322 a special case which converts into an empty string. The start/end
4323 pointers in the original are not used further for this address, as
4324 it is the canonical extracted address which is all that is kept. */
4328 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4330 was_rej_mail = TRUE; /* Reset if accepted */
4331 env_mail_type_t * mail_args; /* Sanity check & validate args */
4334 if ( fl.helo_verify_required
4335 || verify_check_host(&hosts_require_helo) == OK)
4337 smtp_printf("503 HELO or EHLO required\r\n", SP_NO_MORE);
4338 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4339 "HELO/EHLO given", host_and_ident(FALSE));
4342 else if (smtp_mailcmd_max < 0)
4343 smtp_mailcmd_max = expand_mailmax(smtp_accept_max_per_connection);
4347 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4348 US"sender already given");
4352 if (!*smtp_cmd_data)
4354 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4355 US"MAIL must have an address operand");
4359 /* Check to see if the limit for messages per connection would be
4360 exceeded by accepting further messages. */
4362 if (smtp_mailcmd_max > 0 && smtp_mailcmd_count > smtp_mailcmd_max)
4364 smtp_printf("421 too many messages in this connection\r\n", SP_NO_MORE);
4365 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4366 "messages in one connection", host_and_ident(TRUE));
4370 /* Reset for start of message - even if this is going to fail, we
4371 obviously need to throw away any previous data. */
4373 cancel_cutthrough_connection(TRUE, US"MAIL received");
4374 reset_point = smtp_reset(reset_point);
4376 sender_data = recipient_data = NULL;
4378 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4380 if (fl.esmtp) for(;;)
4382 uschar *name, *value, *end;
4383 unsigned long int size;
4384 BOOL arg_error = FALSE;
4386 if (!extract_option(&name, &value)) break;
4388 for (mail_args = env_mail_type_list;
4389 mail_args->value != ENV_MAIL_OPT_NULL;
4392 if (strcmpic(name, mail_args->name) == 0)
4394 if (mail_args->need_value && strcmpic(value, US"") == 0)
4397 switch(mail_args->value)
4399 /* Handle SIZE= by reading the value. We don't do the check till later,
4400 in order to be able to log the sender address on failure. */
4401 case ENV_MAIL_OPT_SIZE:
4402 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4404 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4406 message_size = (int)size;
4412 /* If this session was initiated with EHLO and accept_8bitmime is set,
4413 Exim will have indicated that it supports the BODY=8BITMIME option. In
4414 fact, it does not support this according to the RFCs, in that it does not
4415 take any special action for forwarding messages containing 8-bit
4416 characters. That is why accept_8bitmime is not the default setting, but
4417 some sites want the action that is provided. We recognize both "8BITMIME"
4418 and "7BIT" as body types, but take no action. */
4419 case ENV_MAIL_OPT_BODY:
4420 if (accept_8bitmime) {
4421 if (strcmpic(value, US"8BITMIME") == 0)
4423 else if (strcmpic(value, US"7BIT") == 0)
4428 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4429 US"invalid data for BODY");
4432 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4438 /* Handle the two DSN options, but only if configured to do so (which
4439 will have caused "DSN" to be given in the EHLO response). The code itself
4440 is included only if configured in at build time. */
4442 case ENV_MAIL_OPT_RET:
4443 if (fl.dsn_advertised)
4445 /* Check if RET has already been set */
4448 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4449 US"RET can be specified once only");
4452 dsn_ret = strcmpic(value, US"HDRS") == 0
4454 : strcmpic(value, US"FULL") == 0
4457 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4458 /* Check for invalid invalid value, and exit with error */
4461 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4462 US"Value for RET is invalid");
4467 case ENV_MAIL_OPT_ENVID:
4468 if (fl.dsn_advertised)
4470 /* Check if the dsn envid has been already set */
4473 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4474 US"ENVID can be specified once only");
4477 dsn_envid = string_copy(value);
4478 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4482 /* Handle the AUTH extension. If the value given is not "<>" and either
4483 the ACL says "yes" or there is no ACL but the sending host is
4484 authenticated, we set it up as the authenticated sender. However, if the
4485 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4486 the condition is met. The value of AUTH is an xtext, which means that +,
4487 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4489 case ENV_MAIL_OPT_AUTH:
4490 if (Ustrcmp(value, "<>") != 0)
4495 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4497 /* Put back terminator overrides for error message */
4500 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4501 US"invalid data for AUTH");
4504 if (!acl_smtp_mailauth)
4506 ignore_msg = US"client not authenticated";
4507 rc = sender_host_authenticated ? OK : FAIL;
4511 ignore_msg = US"rejected by ACL";
4512 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4513 &user_msg, &log_msg);
4519 if (authenticated_by == NULL ||
4520 authenticated_by->mail_auth_condition == NULL ||
4521 expand_check_condition(authenticated_by->mail_auth_condition,
4522 authenticated_by->name, US"authenticator"))
4523 break; /* Accept the AUTH */
4525 ignore_msg = US"server_mail_auth_condition failed";
4526 if (authenticated_id != NULL)
4527 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4528 ignore_msg, authenticated_id);
4533 authenticated_sender = NULL;
4534 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4535 value, host_and_ident(TRUE), ignore_msg);
4538 /* Should only get DEFER or ERROR here. Put back terminator
4539 overrides for error message */
4544 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4551 #ifndef DISABLE_PRDR
4552 case ENV_MAIL_OPT_PRDR:
4554 prdr_requested = TRUE;
4559 case ENV_MAIL_OPT_UTF8:
4560 if (!fl.smtputf8_advertised)
4562 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4563 US"SMTPUTF8 used when not advertised");
4567 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4568 message_smtputf8 = allow_utf8_domains = TRUE;
4569 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4571 int old_pool = store_pool;
4572 store_pool = POOL_PERM;
4573 received_protocol = string_sprintf("utf8%s", received_protocol);
4574 store_pool = old_pool;
4579 /* No valid option. Stick back the terminator characters and break
4580 the loop. Do the name-terminator second as extract_option sets
4581 value==name when it found no equal-sign.
4582 An error for a malformed address will occur. */
4583 case ENV_MAIL_OPT_NULL:
4591 /* Break out of for loop if switch() had bad argument or
4592 when start of the email address is reached */
4593 if (arg_error) break;
4596 /* If we have passed the threshold for rate limiting, apply the current
4597 delay, and update it for next time, provided this is a limited host. */
4599 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4600 verify_check_host(&smtp_ratelimit_hosts) == OK)
4602 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4603 smtp_delay_mail/1000.0);
4604 millisleep((int)smtp_delay_mail);
4605 smtp_delay_mail *= smtp_rlm_factor;
4606 if (smtp_delay_mail > (double)smtp_rlm_limit)
4607 smtp_delay_mail = (double)smtp_rlm_limit;
4610 /* Now extract the address, first applying any SMTP-time rewriting. The
4611 TRUE flag allows "<>" as a sender address. */
4613 raw_sender = rewrite_existflags & rewrite_smtp
4614 /* deconst ok as smtp_cmd_data was not const */
4615 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4616 global_rewrite_rules)
4620 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4625 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4629 sender_address = raw_sender;
4631 /* If there is a configured size limit for mail, check that this message
4632 doesn't exceed it. The check is postponed to this point so that the sender
4635 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4637 smtp_printf("552 Message size exceeds maximum permitted\r\n", SP_NO_MORE);
4638 log_write(L_size_reject,
4639 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4640 "message too big: size%s=%d max=%d",
4642 host_and_ident(TRUE),
4643 (message_size == INT_MAX)? ">" : "",
4645 thismessage_size_limit);
4646 sender_address = NULL;
4650 /* Check there is enough space on the disk unless configured not to.
4651 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4652 plus the current message - i.e. we accept the message only if it won't
4653 reduce the space below the threshold. Add 5000 to the size to allow for
4654 overheads such as the Received: line and storing of recipients, etc.
4655 By putting the check here, even when SIZE is not given, it allow VRFY
4656 and EXPN etc. to be used when space is short. */
4658 if (!receive_check_fs(
4659 smtp_check_spool_space && message_size >= 0
4660 ? message_size + 5000 : 0))
4662 smtp_printf("452 Space shortage, please try later\r\n", SP_NO_MORE);
4663 sender_address = NULL;
4667 /* If sender_address is unqualified, reject it, unless this is a locally
4668 generated message, or the sending host or net is permitted to send
4669 unqualified addresses - typically local machines behaving as MUAs -
4670 in which case just qualify the address. The flag is set above at the start
4671 of the SMTP connection. */
4673 if (!sender_domain && *sender_address)
4674 if (f.allow_unqualified_sender)
4676 sender_domain = Ustrlen(sender_address) + 1;
4677 /* deconst ok as sender_address was not const */
4678 sender_address = US rewrite_address_qualify(sender_address, FALSE);
4679 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4684 smtp_printf("501 %s: sender address must contain a domain\r\n", SP_NO_MORE,
4686 log_write(L_smtp_syntax_error,
4687 LOG_MAIN|LOG_REJECT,
4688 "unqualified sender rejected: <%s> %s%s",
4690 host_and_ident(TRUE),
4692 sender_address = NULL;
4696 /* Apply an ACL check if one is defined, before responding. Afterwards,
4697 when pipelining is not advertised, do another sync check in case the ACL
4698 delayed and the client started sending in the meantime. */
4702 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4703 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4709 if (rc == OK || rc == DISCARD)
4711 BOOL more = pipeline_response();
4714 smtp_printf("%s%s%s", more, US"250 OK",
4715 #ifndef DISABLE_PRDR
4716 prdr_requested ? US", PRDR Requested" : US"",
4723 #ifndef DISABLE_PRDR
4725 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4727 smtp_user_msg(US"250", user_msg);
4729 smtp_delay_rcpt = smtp_rlr_base;
4730 f.recipients_discarded = (rc == DISCARD);
4731 was_rej_mail = FALSE;
4735 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4736 sender_address = NULL;
4741 /* The RCPT command requires an address as an operand. There may be any
4742 number of RCPT commands, specifying multiple recipients. We build them all
4743 into a data structure. The start/end values given by parse_extract_address
4744 are not used, as we keep only the extracted address. */
4748 /* We got really to many recipients. A check against configured
4749 limits is done later */
4750 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
4751 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
4753 was_rcpt = fl.rcpt_in_progress = TRUE;
4755 /* There must be a sender address; if the sender was rejected and
4756 pipelining was advertised, we assume the client was pipelining, and do not
4757 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4758 get the same treatment. */
4760 if (!sender_address)
4762 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4764 smtp_printf("503 sender not yet given\r\n", SP_NO_MORE);
4765 was_rej_mail = TRUE;
4769 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4770 US"sender not yet given");
4771 was_rcpt = FALSE; /* Not a valid RCPT */
4777 /* Check for an operand */
4779 if (!smtp_cmd_data[0])
4781 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4782 US"RCPT must have an address operand");
4787 /* Set the DSN flags orcpt and dsn_flags from the session*/
4791 if (fl.esmtp) for(;;)
4793 uschar *name, *value;
4795 if (!extract_option(&name, &value))
4798 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
4800 /* Check whether orcpt has been already set */
4803 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4804 US"ORCPT can be specified once only");
4807 orcpt = string_copy(value);
4808 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
4811 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
4813 /* Check if the notify flags have been already set */
4816 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4817 US"NOTIFY can be specified once only");
4820 if (strcmpic(value, US"NEVER") == 0)
4821 dsn_flags |= rf_notify_never;
4828 while (*pp != 0 && *pp != ',') pp++;
4829 if (*pp == ',') *pp++ = 0;
4830 if (strcmpic(p, US"SUCCESS") == 0)
4832 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
4833 dsn_flags |= rf_notify_success;
4835 else if (strcmpic(p, US"FAILURE") == 0)
4837 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
4838 dsn_flags |= rf_notify_failure;
4840 else if (strcmpic(p, US"DELAY") == 0)
4842 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
4843 dsn_flags |= rf_notify_delay;
4847 /* Catch any strange values */
4848 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4849 US"Invalid value for NOTIFY parameter");
4854 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
4858 /* Unknown option. Stick back the terminator characters and break
4859 the loop. An error for a malformed address will occur. */
4863 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
4870 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
4871 as a recipient address */
4873 recipient = rewrite_existflags & rewrite_smtp
4874 /* deconst ok as smtp_cmd_data was not const */
4875 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4876 global_rewrite_rules)
4879 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
4880 &recipient_domain, FALSE)))
4882 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4887 /* If the recipient address is unqualified, reject it, unless this is a
4888 locally generated message. However, unqualified addresses are permitted
4889 from a configured list of hosts and nets - typically when behaving as
4890 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
4891 really. The flag is set at the start of the SMTP connection.
4893 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
4894 assumed this meant "reserved local part", but the revision of RFC 821 and
4895 friends now makes it absolutely clear that it means *mailbox*. Consequently
4896 we must always qualify this address, regardless. */
4898 if (!recipient_domain)
4899 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
4906 /* Check maximum allowed */
4908 if ( rcpt_count+1 < 0
4909 || rcpt_count > recipients_max_expanded && recipients_max_expanded > 0)
4911 if (recipients_max_reject)
4914 smtp_printf("552 too many recipients\r\n", SP_NO_MORE);
4916 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
4917 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
4922 smtp_printf("452 too many recipients\r\n", SP_NO_MORE);
4924 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
4925 "temporarily rejected: sender=<%s> %s", sender_address,
4926 host_and_ident(TRUE));
4933 /* If we have passed the threshold for rate limiting, apply the current
4934 delay, and update it for next time, provided this is a limited host. */
4936 if (rcpt_count > smtp_rlr_threshold &&
4937 verify_check_host(&smtp_ratelimit_hosts) == OK)
4939 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
4940 smtp_delay_rcpt/1000.0);
4941 millisleep((int)smtp_delay_rcpt);
4942 smtp_delay_rcpt *= smtp_rlr_factor;
4943 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
4944 smtp_delay_rcpt = (double)smtp_rlr_limit;
4947 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
4948 for them. Otherwise, check the access control list for this recipient. As
4949 there may be a delay in this, re-check for a synchronization error
4950 afterwards, unless pipelining was advertised. */
4952 if (f.recipients_discarded)
4955 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
4957 && !f.smtp_in_pipelining_advertised && !check_sync())
4960 /* The ACL was happy */
4964 BOOL more = pipeline_response();
4967 smtp_user_msg(US"250", user_msg);
4969 smtp_printf("250 Accepted\r\n", more);
4970 receive_add_recipient(recipient, -1);
4972 /* Set the dsn flags in the recipients_list */
4973 recipients_list[recipients_count-1].orcpt = orcpt;
4974 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
4976 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
4977 recipients_list[recipients_count-1].orcpt,
4978 recipients_list[recipients_count-1].dsn_flags); */
4981 /* The recipient was discarded */
4983 else if (rc == DISCARD)
4986 smtp_user_msg(US"250", user_msg);
4988 smtp_printf("250 Accepted\r\n", SP_NO_MORE);
4991 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
4992 "discarded by %s ACL%s%s", host_and_ident(TRUE),
4993 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
4994 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
4995 log_msg ? US": " : US"", log_msg ? log_msg : US"");
4998 /* Either the ACL failed the address, or it was deferred. */
5002 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5003 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5008 /* The DATA command is legal only if it follows successful MAIL FROM
5009 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5010 not counted as a protocol error if it follows RCPT (which must have been
5011 rejected if there are no recipients.) This function is complete when a
5012 valid DATA command is encountered.
5014 Note concerning the code used: RFC 2821 says this:
5016 - If there was no MAIL, or no RCPT, command, or all such commands
5017 were rejected, the server MAY return a "command out of sequence"
5018 (503) or "no valid recipients" (554) reply in response to the
5021 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5022 because it is the same whether pipelining is in use or not.
5024 If all the RCPT commands that precede DATA provoked the same error message
5025 (often indicating some kind of system error), it is helpful to include it
5026 with the DATA rejection (an idea suggested by Tony Finch). */
5033 if (chunking_state != CHUNKING_OFFERED)
5035 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5036 US"BDAT command used when CHUNKING not advertised");
5040 /* grab size, endmarker */
5042 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5044 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5045 US"missing size for BDAT command");
5048 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5049 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5050 chunking_data_left = chunking_datasize;
5051 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5052 (int)chunking_state, chunking_data_left);
5054 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
5063 f.bdat_readers_wanted = FALSE;
5065 DATA_BDAT: /* Common code for DATA and BDAT */
5066 #ifndef DISABLE_PIPE_CONNECT
5067 fl.pipe_connect_acceptable = FALSE;
5069 if (!discarded && recipients_count <= 0)
5071 if (fl.rcpt_smtp_response_same && rcpt_smtp_response)
5073 uschar *code = US"503";
5074 int len = Ustrlen(rcpt_smtp_response);
5075 smtp_respond(code, 3, SR_NOT_FINAL, US"All RCPT commands were rejected with "
5077 /* Responses from smtp_printf() will have \r\n on the end */
5078 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5079 rcpt_smtp_response[len-2] = 0;
5080 smtp_respond(code, 3, SR_NOT_FINAL, rcpt_smtp_response);
5082 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5083 smtp_printf("503 Valid RCPT command must precede %s\r\n", SP_NO_MORE,
5084 smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]);
5086 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5087 smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA
5088 ? US"valid RCPT command must precede DATA"
5089 : US"valid RCPT command must precede BDAT");
5091 if (chunking_state > CHUNKING_OFFERED)
5093 bdat_push_receive_functions();
5099 if (toomany && recipients_max_reject)
5101 sender_address = NULL; /* This will allow a new MAIL without RSET */
5102 sender_address_unrewritten = NULL;
5103 smtp_printf("554 Too many recipients\r\n", SP_NO_MORE);
5105 if (chunking_state > CHUNKING_OFFERED)
5107 bdat_push_receive_functions();
5113 if (chunking_state > CHUNKING_OFFERED)
5114 rc = OK; /* There is no predata ACL or go-ahead output for BDAT */
5117 /* If there is a predata-ACL, re-check the synchronization afterwards,
5118 since the ACL may have delayed. To handle cutthrough delivery enforce a
5119 dummy call to get the DATA command sent. */
5121 if (!acl_smtp_predata && cutthrough.cctx.sock < 0)
5125 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5126 f.enable_dollar_recipients = TRUE;
5127 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5129 f.enable_dollar_recipients = FALSE;
5130 if (rc == OK && !check_sync())
5134 { /* Either the ACL failed the address, or it was deferred. */
5135 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5141 smtp_user_msg(US"354", user_msg);
5144 "354 Enter message, ending with \".\" on a line by itself\r\n", SP_NO_MORE);
5147 if (f.bdat_readers_wanted)
5148 bdat_push_receive_functions();
5151 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5152 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5153 US &on, sizeof(on));
5156 message_ended = END_NOTENDED; /* Indicate in middle of data */
5167 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5168 &start, &end, &recipient_domain, FALSE)))
5170 smtp_printf("501 %s\r\n", SP_NO_MORE, errmess);
5174 if (!recipient_domain)
5175 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5179 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5180 &user_msg, &log_msg)) != OK)
5181 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5185 address_item * addr = deliver_make_addr(address, FALSE);
5187 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5188 -1, -1, NULL, NULL, NULL))
5191 s = string_sprintf("250 <%s> is deliverable", address);
5195 s = (addr->user_message != NULL)?
5196 string_sprintf("451 <%s> %s", address, addr->user_message) :
5197 string_sprintf("451 Cannot resolve <%s> at this time", address);
5201 s = (addr->user_message != NULL)?
5202 string_sprintf("550 <%s> %s", address, addr->user_message) :
5203 string_sprintf("550 <%s> is not deliverable", address);
5204 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5205 smtp_cmd_argument, host_and_ident(TRUE));
5209 smtp_printf("%s\r\n", SP_NO_MORE, s);
5217 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5219 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5222 BOOL save_log_testing_mode = f.log_testing_mode;
5223 f.address_test_mode = f.log_testing_mode = TRUE;
5224 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5225 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5227 f.address_test_mode = FALSE;
5228 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5237 if (!fl.tls_advertised)
5239 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5240 US"STARTTLS command used when not advertised");
5244 /* Apply an ACL check if one is defined */
5246 if ( acl_smtp_starttls
5247 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5248 &user_msg, &log_msg)) != OK
5251 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5255 /* RFC 2487 is not clear on when this command may be sent, though it
5256 does state that all information previously obtained from the client
5257 must be discarded if a TLS session is started. It seems reasonable to
5258 do an implied RSET when STARTTLS is received. */
5260 incomplete_transaction_log(US"STARTTLS");
5261 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5262 reset_point = smtp_reset(reset_point);
5264 cmd_list[CL_STLS].is_mail_cmd = FALSE;
5266 /* There's an attack where more data is read in past the STARTTLS command
5267 before TLS is negotiated, then assumed to be part of the secure session
5268 when used afterwards; we use segregated input buffers, so are not
5269 vulnerable, but we want to note when it happens and, for sheer paranoia,
5270 ensure that the buffer is "wiped".
5271 Pipelining sync checks will normally have protected us too, unless disabled
5272 by configuration. */
5277 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5278 if (tls_in.active.sock < 0)
5279 smtp_inend = smtp_inptr = smtp_inbuffer;
5280 /* and if TLS is already active, tls_server_start() should fail */
5283 /* There is nothing we value in the input buffer and if TLS is successfully
5284 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5285 fresh content into it. The buffer contains arbitrary content from an
5286 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5287 It seems safest to just wipe away the content rather than leave it as a
5288 target to jump to. */
5290 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5292 /* Attempt to start up a TLS session, and if successful, discard all
5293 knowledge that was obtained previously. At least, that's what the RFC says,
5294 and that's what happens by default. However, in order to work round YAEB,
5295 there is an option to remember the esmtp state. Sigh.
5297 We must allow for an extra EHLO command and an extra AUTH command after
5298 STARTTLS that don't add to the nonmail command count. */
5301 if ((rc = tls_server_start(&s)) == OK)
5303 if (!tls_remember_esmtp)
5304 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5305 cmd_list[CL_EHLO].is_mail_cmd = TRUE;
5306 cmd_list[CL_AUTH].is_mail_cmd = TRUE;
5307 cmd_list[CL_TLAU].is_mail_cmd = TRUE;
5308 if (sender_helo_name)
5310 sender_helo_name = NULL;
5311 host_build_sender_fullhost(); /* Rebuild */
5312 set_process_info("handling incoming TLS connection from %s",
5313 host_and_ident(FALSE));
5316 (sender_host_address ? protocols : protocols_local)
5318 ? pextend + (sender_host_authenticated ? pauthed : 0)
5320 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5323 sender_host_auth_pubname = sender_host_authenticated = NULL;
5324 authenticated_id = NULL;
5325 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5326 DEBUG(D_tls) debug_printf("TLS active\n");
5327 break; /* Successful STARTTLS */
5330 (void) smtp_log_tls_fail(s);
5332 /* Some local configuration problem was discovered before actually trying
5333 to do a TLS handshake; give a temporary error. */
5337 smtp_printf("454 TLS currently unavailable\r\n", SP_NO_MORE);
5341 /* Hard failure. Reject everything except QUIT or closed connection. One
5342 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5343 set, but we must still reject all incoming commands. Another is a handshake
5344 failure - and there may some encrypted data still in the pipe to us, which we
5345 see as garbage commands. */
5347 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5348 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5351 log_close_event(US"by EOF");
5352 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5356 /* It is perhaps arguable as to which exit ACL should be called here,
5357 but as it is probably a situation that almost never arises, it
5358 probably doesn't matter. We choose to call the real QUIT ACL, which in
5359 some sense is perhaps "right". */
5362 f.smtp_in_quit = TRUE;
5365 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5366 &log_msg)) == ERROR))
5367 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5370 smtp_respond(US"221", 3, SR_FINAL, user_msg);
5372 smtp_printf("221 %s closing connection\r\n", SP_NO_MORE, smtp_active_hostname);
5373 log_close_event(US"by QUIT");
5378 smtp_printf("554 Security failure\r\n", SP_NO_MORE);
5381 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5386 /* The ACL for QUIT is provided for gathering statistical information or
5387 similar; it does not affect the response code, but it can supply a custom
5391 smtp_quit_handler(&user_msg, &log_msg);
5397 smtp_rset_handler();
5398 cancel_cutthrough_connection(TRUE, US"RSET received");
5399 reset_point = smtp_reset(reset_point);
5406 smtp_printf("250 OK\r\n", SP_NO_MORE);
5410 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5411 used, a check will be done for permitted hosts. Show STARTTLS only if not
5412 already in a TLS session and if it would be advertised in the EHLO
5417 smtp_printf("214-Commands supported:\r\n214", SP_MORE);
5418 smtp_printf(" AUTH", SP_MORE);
5420 if (tls_in.active.sock < 0 &&
5421 verify_check_host(&tls_advertise_hosts) != FAIL)
5422 smtp_printf(" STARTTLS", SP_MORE);
5424 smtp_printf(" HELO EHLO MAIL RCPT DATA BDAT", SP_MORE);
5425 smtp_printf(" NOOP QUIT RSET HELP", SP_MORE);
5426 if (acl_smtp_etrn) smtp_printf(" ETRN", SP_MORE);
5427 if (acl_smtp_expn) smtp_printf(" EXPN", SP_MORE);
5428 if (acl_smtp_vrfy) smtp_printf(" VRFY", SP_MORE);
5429 #ifdef EXPERIMENTAL_XCLIENT
5430 if (proxy_session || verify_check_host(&hosts_xclient) != FAIL)
5431 smtp_printf(" XCLIENT", SP_MORE);
5433 smtp_printf("\r\n", SP_NO_MORE);
5438 incomplete_transaction_log(US"connection lost");
5439 smtp_notquit_exit(US"connection-lost", US"421",
5440 US"%s lost input connection", smtp_active_hostname);
5442 /* Don't log by default unless in the middle of a message, as some mailers
5443 just drop the call rather than sending QUIT, and it clutters up the logs.
5446 if (sender_address || recipients_count > 0)
5447 log_write(L_lost_incoming_connection, LOG_MAIN,
5448 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5449 f.sender_host_unknown ? "EOF" : "disconnection",
5450 f.tcp_in_fastopen_logged
5453 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5455 host_and_ident(FALSE), smtp_read_error,
5456 string_timesince(&smtp_connection_start)
5460 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5461 smtp_get_connection_info(),
5462 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5464 string_timesince(&smtp_connection_start)
5475 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5476 US"ETRN is not permitted inside a transaction");
5480 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5481 host_and_ident(FALSE));
5483 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5484 &user_msg, &log_msg)) != OK)
5486 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5490 /* Compute the serialization key for this command. */
5492 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5494 /* If a command has been specified for running as a result of ETRN, we
5495 permit any argument to ETRN. If not, only the # standard form is permitted,
5496 since that is strictly the only kind of ETRN that can be implemented
5497 according to the RFC. */
5499 if (smtp_etrn_command)
5503 etrn_command = smtp_etrn_command;
5504 deliver_domain = smtp_cmd_data;
5505 rc = transport_set_up_command(&argv, smtp_etrn_command, TSUC_EXPAND_ARGS, 0, NULL,
5506 US"ETRN processing", &error);
5507 deliver_domain = NULL;
5510 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5512 smtp_printf("458 Internal failure\r\n", SP_NO_MORE);
5517 /* Else set up to call Exim with the -R option. */
5521 if (*smtp_cmd_data++ != '#')
5523 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5524 US"argument must begin with #");
5527 etrn_command = US"exim -R";
5528 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5529 *queue_name ? 4 : 2,
5530 US"-R", smtp_cmd_data,
5531 US"-MCG", queue_name);
5534 /* If we are host-testing, don't actually do anything. */
5540 debug_printf("ETRN command is: %s\n", etrn_command);
5541 debug_printf("ETRN command execution skipped\n");
5543 if (user_msg == NULL) smtp_printf("250 OK\r\n", SP_NO_MORE);
5544 else smtp_user_msg(US"250", user_msg);
5549 /* If ETRN queue runs are to be serialized, check the database to
5550 ensure one isn't already running. */
5552 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5554 smtp_printf("458 Already processing %s\r\n", SP_NO_MORE, smtp_cmd_data);
5558 /* Fork a child process and run the command. We don't want to have to
5559 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5560 forking. It should be set that way anyway for external incoming SMTP,
5561 but we save and restore to be tidy. If serialization is required, we
5562 actually run the command in yet another process, so we can wait for it
5563 to complete and then remove the serialization lock. */
5565 oldsignal = signal(SIGCHLD, SIG_IGN);
5567 if ((pid = exim_fork(US"etrn-command")) == 0)
5569 smtp_input = FALSE; /* This process is not associated with the */
5570 (void)fclose(smtp_in); /* SMTP call any more. */
5571 (void)fclose(smtp_out);
5573 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5575 /* If not serializing, do the exec right away. Otherwise, fork down
5576 into another process. */
5578 if ( !smtp_etrn_serialize
5579 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5581 DEBUG(D_exec) debug_print_argv(argv);
5582 exim_nullstd(); /* Ensure std{in,out,err} exist */
5583 /* argv[0] should be untainted, from child_exec_exim() */
5584 execv(CS argv[0], (char *const *)argv);
5585 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5586 etrn_command, strerror(errno));
5587 _exit(EXIT_FAILURE); /* paranoia */
5590 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5591 is, we are in the first subprocess, after forking again. All we can do
5592 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5593 complete, before removing the serialization. */
5596 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5597 "failed: %s", strerror(errno));
5601 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5603 (void)wait(&status);
5604 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5608 enq_end(etrn_serialize_key);
5609 exim_underbar_exit(EXIT_SUCCESS);
5612 /* Back in the top level SMTP process. Check that we started a subprocess
5613 and restore the signal state. */
5617 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5619 smtp_printf("458 Unable to fork process\r\n", SP_NO_MORE);
5620 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5624 smtp_printf("250 OK\r\n", SP_NO_MORE);
5626 smtp_user_msg(US"250", user_msg);
5628 signal(SIGCHLD, oldsignal);
5633 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5634 US"unexpected argument data");
5638 /* This currently happens only for NULLs, but could be extended. */
5641 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5642 US"NUL character(s) present (shown as '?')");
5643 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5651 unsigned nchars = 150;
5652 uschar * buf = receive_getbuf(&nchars); /* destructive read */
5654 incomplete_transaction_log(US"sync failure");
5655 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5656 "(next input sent too soon: pipelining was%s advertised): "
5657 "rejected \"%s\" %s next input=\"%s\" (%u bytes)",
5658 f.smtp_in_pipelining_advertised ? "" : " not",
5659 smtp_cmd_buffer, host_and_ident(TRUE),
5660 string_printing(buf), nchars);
5661 smtp_notquit_exit(US"synchronization-error", US"554",
5662 US"SMTP synchronization error");
5663 done = 1; /* Pretend eof - drops connection */
5668 case TOO_MANY_NONMAIL_CMD:
5669 s = smtp_cmd_buffer;
5670 while (*s && !isspace(*s)) s++;
5671 incomplete_transaction_log(US"too many non-mail commands");
5672 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5673 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5674 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5675 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5676 done = 1; /* Pretend eof - drops connection */
5679 #ifdef SUPPORT_PROXY
5680 case PROXY_FAIL_IGNORE_CMD:
5681 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", SP_NO_MORE);
5686 if (unknown_command_count++ >= smtp_max_unknown_commands)
5688 log_write(L_smtp_syntax_error, LOG_MAIN,
5689 "SMTP syntax error in \"%s\" %s %s",
5690 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5691 US"unrecognized command");
5692 incomplete_transaction_log(US"unrecognized command");
5693 smtp_notquit_exit(US"bad-commands", US"500",
5694 US"Too many unrecognized commands");
5696 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5697 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5698 string_printing(smtp_cmd_buffer));
5701 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5702 US"unrecognized command");
5706 /* This label is used by goto's inside loops that want to break out to
5707 the end of the command-processing loop. */
5710 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5711 last_was_rcpt = was_rcpt; /* protocol error handling */
5714 return done - 2; /* Convert yield values */
5720 authres_smtpauth(gstring * g)
5722 if (!sender_host_authenticated)
5725 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5727 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
5728 g = authenticated_id
5729 ? string_append(g, 2, US") x509.auth=", authenticated_id)
5730 : string_cat(g, US") reason=x509.auth");
5732 g = authenticated_id
5733 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
5734 : string_cat(g, US", no id saved)");
5736 if (authenticated_sender)
5737 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5745 /* End of smtp_in.c */