1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* Copyright (c) The Exim Maintainers 2020 */
7 /* See the file NOTICE for conditions of use and distribution. */
9 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
34 uschar *tcp_wrappers_name;
38 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
39 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
40 commands that accept arguments, and this in particular applies to AUTH, where
41 the data can be quite long. More recently this value was 2048 in Exim;
42 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
43 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
44 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
45 we need room to handle large base64-encoded AUTHs for GSSAPI.
48 #define SMTP_CMD_BUFFER_SIZE 16384
50 /* Size of buffer for reading SMTP incoming packets */
52 #define IN_BUFFER_SIZE 8192
54 /* Structure for SMTP command list */
61 short int is_mail_cmd;
64 /* Codes for identifying commands. We order them so that those that come first
65 are those for which synchronization is always required. Checking this can help
69 /* These commands are required to be synchronized, i.e. to be the last in a
70 block of commands when pipelining. */
72 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
73 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
74 ETRN_CMD, /* This by analogy with TURN from the RFC */
75 STARTTLS_CMD, /* Required by the STARTTLS RFC */
76 TLS_AUTH_CMD, /* auto-command at start of SSL */
78 /* This is a dummy to identify the non-sync commands when pipelining */
80 NON_SYNC_CMD_PIPELINING,
82 /* These commands need not be synchronized when pipelining */
84 MAIL_CMD, RCPT_CMD, RSET_CMD,
86 /* This is a dummy to identify the non-sync commands when not pipelining */
88 NON_SYNC_CMD_NON_PIPELINING,
90 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
91 processed the message is sent using a series of BDAT commands"
92 implies that BDAT should be synchronized. However, we see Google, at least,
93 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
94 processing of the RCPT response(s). We shall do the same, and not require
95 synch for BDAT. Worse, as the chunk may (very likely will) follow the
96 command-header in the same packet we cannot do the usual "is there any
97 follow-on data after the command line" even for non-pipeline mode.
98 So we'll need an explicit check after reading the expected chunk amount
99 when non-pipe, before sending the ACK. */
103 /* I have been unable to find a statement about the use of pipelining
104 with AUTH, so to be on the safe side it is here, though I kind of feel
105 it should be up there with the synchronized commands. */
109 /* I'm not sure about these, but I don't think they matter. */
114 PROXY_FAIL_IGNORE_CMD,
117 /* These are specials that don't correspond to actual commands */
119 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
120 TOO_MANY_NONMAIL_CMD };
123 /* This is a convenience macro for adding the identity of an SMTP command
124 to the circular buffer that holds a list of the last n received. */
127 smtp_connection_had[smtp_ch_index++] = n; \
128 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
131 /*************************************************
132 * Local static variables *
133 *************************************************/
136 BOOL auth_advertised :1;
138 BOOL tls_advertised :1;
140 BOOL dsn_advertised :1;
142 BOOL helo_required :1;
145 BOOL helo_accept_junk :1;
146 #ifndef DISABLE_PIPE_CONNECT
147 BOOL pipe_connect_acceptable :1;
149 BOOL rcpt_smtp_response_same :1;
150 BOOL rcpt_in_progress :1;
151 BOOL smtp_exit_function_called :1;
153 BOOL smtputf8_advertised :1;
156 .helo_required = FALSE,
157 .helo_verify = FALSE,
158 .smtp_exit_function_called = FALSE,
161 static auth_instance *authenticated_by;
162 static int count_nonmail;
163 static int nonmail_command_count;
164 static int synprot_error_count;
165 static int unknown_command_count;
166 static int sync_cmd_limit;
167 static int smtp_write_error = 0;
169 static uschar *rcpt_smtp_response;
170 static uschar *smtp_data_buffer;
171 static uschar *smtp_cmd_data;
173 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
174 final fields of all except AUTH are forced TRUE at the start of a new message
175 setup, to allow one of each between messages that is not counted as a nonmail
176 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
177 allow a new EHLO after starting up TLS.
179 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
180 counted. However, the flag is changed when AUTH is received, so that multiple
181 failing AUTHs will eventually hit the limit. After a successful AUTH, another
182 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
183 forced TRUE, to allow for the re-authentication that can happen at that point.
185 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
186 count of non-mail commands and possibly provoke an error.
188 tls_auth is a pseudo-command, never expected in input. It is activated
189 on TLS startup and looks for a tls authenticator. */
191 static smtp_cmd_list cmd_list[] = {
192 /* name len cmd has_arg is_mail_cmd */
194 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
195 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
196 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
197 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
199 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
200 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
203 /* If you change anything above here, also fix the definitions below. */
205 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
206 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
207 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
208 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
209 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
210 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
211 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
212 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
213 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
214 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
217 static smtp_cmd_list *cmd_list_end =
218 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
220 #define CMD_LIST_RSET 0
221 #define CMD_LIST_HELO 1
222 #define CMD_LIST_EHLO 2
223 #define CMD_LIST_AUTH 3
224 #define CMD_LIST_STARTTLS 4
225 #define CMD_LIST_TLS_AUTH 5
227 /* This list of names is used for performing the smtp_no_mail logging action.
228 It must be kept in step with the SCH_xxx enumerations. */
230 uschar * smtp_names[] =
232 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
233 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
234 US"STARTTLS", US"VRFY" };
236 static uschar *protocols_local[] = {
237 US"local-smtp", /* HELO */
238 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
239 US"local-esmtp", /* EHLO */
240 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
241 US"local-esmtpa", /* EHLO->AUTH */
242 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
244 static uschar *protocols[] = {
246 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
247 US"esmtp", /* EHLO */
248 US"esmtps", /* EHLO->STARTTLS->EHLO */
249 US"esmtpa", /* EHLO->AUTH */
250 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
255 #define pcrpted 1 /* added to pextend or pnormal */
256 #define pauthed 2 /* added to pextend */
258 /* Sanity check and validate optional args to MAIL FROM: envelope */
261 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
265 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
271 uschar * name; /* option requested during MAIL cmd */
272 int value; /* enum type */
273 BOOL need_value; /* TRUE requires value (name=value pair format)
274 FALSE is a singleton */
276 static env_mail_type_t env_mail_type_list[] = {
277 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
278 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
279 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
281 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
283 { US"RET", ENV_MAIL_OPT_RET, TRUE },
284 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
286 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
288 /* keep this the last entry */
289 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
292 /* When reading SMTP from a remote host, we have to use our own versions of the
293 C input-reading functions, in order to be able to flush the SMTP output only
294 when about to read more data from the socket. This is the only way to get
295 optimal performance when the client is using pipelining. Flushing for every
296 command causes a separate packet and reply packet each time; saving all the
297 responses up (when pipelining) combines them into one packet and one response.
299 For simplicity, these functions are used for *all* SMTP input, not only when
300 receiving over a socket. However, after setting up a secure socket (SSL), input
301 is read via the OpenSSL library, and another set of functions is used instead
304 These functions are set in the receive_getc etc. variables and called with the
305 same interface as the C functions. However, since there can only ever be
306 one incoming SMTP call, we just use a single buffer and flags. There is no need
307 to implement a complicated private FILE-like structure.*/
309 static uschar *smtp_inbuffer;
310 static uschar *smtp_inptr;
311 static uschar *smtp_inend;
312 static int smtp_had_eof;
313 static int smtp_had_error;
316 /* forward declarations */
317 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
318 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
319 static void smtp_quit_handler(uschar **, uschar **);
320 static void smtp_rset_handler(void);
322 /*************************************************
323 * Recheck synchronization *
324 *************************************************/
326 /* Synchronization checks can never be perfect because a packet may be on its
327 way but not arrived when the check is done. Normally, the checks happen when
328 commands are read: Exim ensures that there is no more input in the input buffer.
329 In normal cases, the response to the command will be fast, and there is no
332 However, for some commands an ACL is run, and that can include delays. In those
333 cases, it is useful to do another check on the input just before sending the
334 response. This also applies at the start of a connection. This function does
335 that check by means of the select() function, as long as the facility is not
336 disabled or inappropriate. A failure of select() is ignored.
338 When there is unwanted input, we read it so that it appears in the log of the
342 Returns: TRUE if all is well; FALSE if there is input pending
346 wouldblock_reading(void)
350 struct timeval tzero;
353 if (tls_in.active.sock >= 0)
354 return !tls_could_read();
357 if (smtp_inptr < smtp_inend)
360 fd = fileno(smtp_in);
365 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
367 if (rc <= 0) return TRUE; /* Not ready to read */
368 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
369 if (rc < 0) return TRUE; /* End of file or error */
378 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
381 return wouldblock_reading();
385 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
386 a reponse with the one following. */
389 pipeline_response(void)
391 if ( !smtp_enforce_sync || !sender_host_address
392 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
395 if (wouldblock_reading()) return FALSE;
396 f.smtp_in_pipelining_used = TRUE;
401 #ifndef DISABLE_PIPE_CONNECT
403 pipeline_connect_sends(void)
405 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
408 if (wouldblock_reading()) return FALSE;
409 f.smtp_in_early_pipe_used = TRUE;
414 /*************************************************
415 * Log incomplete transactions *
416 *************************************************/
418 /* This function is called after a transaction has been aborted by RSET, QUIT,
419 connection drops or other errors. It logs the envelope information received
420 so far in order to preserve address verification attempts.
422 Argument: string to indicate what aborted the transaction
427 incomplete_transaction_log(uschar *what)
429 if (!sender_address /* No transaction in progress */
430 || !LOGGING(smtp_incomplete_transaction))
433 /* Build list of recipients for logging */
435 if (recipients_count > 0)
437 raw_recipients = store_get(recipients_count * sizeof(uschar *), FALSE);
438 for (int i = 0; i < recipients_count; i++)
439 raw_recipients[i] = recipients_list[i].address;
440 raw_recipients_count = recipients_count;
443 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
444 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
451 smtp_command_timeout_exit(void)
453 log_write(L_lost_incoming_connection,
454 LOG_MAIN, "SMTP command timeout on%s connection from %s",
455 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
456 if (smtp_batched_input)
457 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
458 smtp_notquit_exit(US"command-timeout", US"421",
459 US"%s: SMTP command timeout - closing connection",
460 smtp_active_hostname);
461 exim_exit(EXIT_FAILURE);
465 smtp_command_sigterm_exit(void)
467 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
468 if (smtp_batched_input)
469 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
470 smtp_notquit_exit(US"signal-exit", US"421",
471 US"%s: Service not available - closing connection", smtp_active_hostname);
472 exim_exit(EXIT_FAILURE);
476 smtp_data_timeout_exit(void)
478 log_write(L_lost_incoming_connection,
479 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
480 sender_fullhost ? sender_fullhost : US"local process", sender_address);
481 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
482 /* Does not return */
486 smtp_data_sigint_exit(void)
488 log_write(0, LOG_MAIN, "%s closed after %s",
489 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
490 receive_bomb_out(US"signal-exit",
491 US"Service not available - SIGTERM or SIGINT received");
492 /* Does not return */
497 /* Refill the buffer, and notify DKIM verification code.
498 Return false for error or EOF.
502 smtp_refill(unsigned lim)
505 if (!smtp_out) return FALSE;
507 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
509 /* Limit amount read, so non-message data is not fed to DKIM.
510 Take care to not touch the safety NUL at the end of the buffer. */
512 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
514 if (smtp_receive_timeout > 0) ALARM_CLR(0);
517 /* Must put the error text in fixed store, because this might be during
518 header reading, where it releases unused store above the header. */
521 if (had_command_timeout) /* set by signal handler */
522 smtp_command_timeout_exit(); /* does not return */
523 if (had_command_sigterm)
524 smtp_command_sigterm_exit();
525 if (had_data_timeout)
526 smtp_data_timeout_exit();
528 smtp_data_sigint_exit();
530 smtp_had_error = save_errno;
531 smtp_read_error = string_copy_perm(
532 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
539 dkim_exim_verify_feed(smtp_inbuffer, rc);
541 smtp_inend = smtp_inbuffer + rc;
542 smtp_inptr = smtp_inbuffer;
546 /*************************************************
547 * SMTP version of getc() *
548 *************************************************/
550 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
551 it flushes the output, and refills the buffer, with a timeout. The signal
552 handler is set appropriately by the calling function. This function is not used
553 after a connection has negotiated itself into an TLS/SSL state.
555 Arguments: lim Maximum amount to read/buffer
556 Returns: the next character or EOF
560 smtp_getc(unsigned lim)
562 if (smtp_inptr >= smtp_inend)
563 if (!smtp_refill(lim))
565 return *smtp_inptr++;
569 smtp_getbuf(unsigned * len)
574 if (smtp_inptr >= smtp_inend)
575 if (!smtp_refill(*len))
576 { *len = 0; return NULL; }
578 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
589 int n = smtp_inend - smtp_inptr;
591 dkim_exim_verify_feed(smtp_inptr, n);
596 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
597 previous BDAT chunk and getting new ones when we run out. Uses the
598 underlying smtp_getc or tls_getc both for that and for getting the
599 (buffered) data byte. EOD signals (an expected) no further data.
600 ERR signals a protocol error, and EOF a closed input stream.
602 Called from read_bdat_smtp() in receive.c for the message body, but also
603 by the headers read loop in receive_msg(); manipulates chunking_state
604 to handle the BDAT command/response.
605 Placed here due to the correlation with the above smtp_getc(), which it wraps,
606 and also by the need to do smtp command/response handling.
608 Arguments: lim (ignored)
609 Returns: the next character or ERR, EOD or EOF
613 bdat_getc(unsigned lim)
615 uschar * user_msg = NULL;
624 if (chunking_data_left > 0)
625 return lwr_receive_getc(chunking_data_left--);
627 receive_getc = lwr_receive_getc;
628 receive_getbuf = lwr_receive_getbuf;
629 receive_ungetc = lwr_receive_ungetc;
631 dkim_save = dkim_collect_input;
632 dkim_collect_input = 0;
635 /* Unless PIPELINING was offered, there should be no next command
636 until after we ack that chunk */
638 if (!f.smtp_in_pipelining_advertised && !check_sync())
640 unsigned n = smtp_inend - smtp_inptr;
643 incomplete_transaction_log(US"sync failure");
644 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
645 "(next input sent too soon: pipelining was not advertised): "
646 "rejected \"%s\" %s next input=\"%s\"%s",
647 smtp_cmd_buffer, host_and_ident(TRUE),
648 string_printing(string_copyn(smtp_inptr, n)),
649 smtp_inend - smtp_inptr > n ? "..." : "");
650 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
651 US"SMTP synchronization error");
652 goto repeat_until_rset;
655 /* If not the last, ack the received chunk. The last response is delayed
656 until after the data ACL decides on it */
658 if (chunking_state == CHUNKING_LAST)
661 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
666 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
667 chunking_state = CHUNKING_OFFERED;
668 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
670 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
671 QUIT, RSET or NOOP but handling them seems obvious */
674 switch(smtp_read_command(TRUE, 1))
677 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
678 US"only BDAT permissible after non-LAST BDAT");
681 switch(smtp_read_command(TRUE, 1))
683 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
684 case EOF_CMD: return EOF;
685 case RSET_CMD: smtp_rset_handler(); return ERR;
686 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
687 US"only RSET accepted now") > 0)
689 goto repeat_until_rset;
693 smtp_quit_handler(&user_msg, &log_msg);
704 smtp_printf("250 OK\r\n", FALSE);
711 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
713 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
714 US"missing size for BDAT command");
717 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
718 ? CHUNKING_LAST : CHUNKING_ACTIVE;
719 chunking_data_left = chunking_datasize;
720 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
721 (int)chunking_state, chunking_data_left);
723 if (chunking_datasize == 0)
724 if (chunking_state == CHUNKING_LAST)
728 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
729 US"zero size for BDAT command");
730 goto repeat_until_rset;
733 receive_getc = bdat_getc;
734 receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */
735 receive_ungetc = bdat_ungetc;
737 dkim_collect_input = dkim_save;
739 break; /* to top of main loop */
746 bdat_getbuf(unsigned * len)
750 if (chunking_data_left <= 0)
751 { *len = 0; return NULL; }
753 if (*len > chunking_data_left) *len = chunking_data_left;
754 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
755 chunking_data_left -= *len;
760 bdat_flush_data(void)
762 while (chunking_data_left)
764 unsigned n = chunking_data_left;
765 if (!bdat_getbuf(&n)) break;
768 receive_getc = lwr_receive_getc;
769 receive_getbuf = lwr_receive_getbuf;
770 receive_ungetc = lwr_receive_ungetc;
772 if (chunking_state != CHUNKING_LAST)
774 chunking_state = CHUNKING_OFFERED;
775 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
782 /*************************************************
783 * SMTP version of ungetc() *
784 *************************************************/
786 /* Puts a character back in the input buffer. Only ever
792 Returns: the character
806 chunking_data_left++;
807 return lwr_receive_ungetc(ch);
812 /*************************************************
813 * SMTP version of feof() *
814 *************************************************/
816 /* Tests for a previous EOF
819 Returns: non-zero if the eof flag is set
831 /*************************************************
832 * SMTP version of ferror() *
833 *************************************************/
835 /* Tests for a previous read error, and returns with errno
836 restored to what it was when the error was detected.
839 Returns: non-zero if the error flag is set
845 errno = smtp_had_error;
846 return smtp_had_error;
851 /*************************************************
852 * Test for characters in the SMTP buffer *
853 *************************************************/
855 /* Used at the end of a message
864 return smtp_inptr < smtp_inend;
869 /*************************************************
870 * Write formatted string to SMTP channel *
871 *************************************************/
873 /* This is a separate function so that we don't have to repeat everything for
874 TLS support or debugging. It is global so that the daemon and the
875 authentication functions can use it. It does not return any error indication,
876 because major problems such as dropped connections won't show up till an output
877 flush for non-TLS connections. The smtp_fflush() function is available for
878 checking that: for convenience, TLS output errors are remembered here so that
879 they are also picked up later by smtp_fflush().
881 This function is exposed to the local_scan API; do not change the signature.
885 more further data expected
886 ... optional arguments
892 smtp_printf(const char *format, BOOL more, ...)
897 smtp_vprintf(format, more, ap);
901 /* This is split off so that verify.c:respond_printf() can, in effect, call
902 smtp_printf(), bearing in mind that in C a vararg function can't directly
903 call another vararg function, only a function which accepts a va_list.
905 This function is exposed to the local_scan API; do not change the signature.
907 /*XXX consider passing caller-info in, for string_vformat-onward */
910 smtp_vprintf(const char *format, BOOL more, va_list ap)
912 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
915 /* Use taint-unchecked routines for writing into big_buffer, trusting
916 that we'll never expand it. */
918 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
919 string_from_gstring(&gs);
923 uschar *msg_copy, *cr, *end;
924 msg_copy = string_copy(gs.s);
925 end = msg_copy + gs.ptr;
926 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
927 memmove(cr, cr + 1, (end--) - cr);
928 debug_printf("SMTP>> %s", msg_copy);
933 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
934 smtp_closedown(US"Unexpected error");
935 exim_exit(EXIT_FAILURE);
938 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
939 have had the same. Note: this code is also present in smtp_respond(). It would
940 be tidier to have it only in one place, but when it was added, it was easier to
941 do it that way, so as not to have to mess with the code for the RCPT command,
942 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
944 if (fl.rcpt_in_progress)
946 if (rcpt_smtp_response == NULL)
947 rcpt_smtp_response = string_copy(big_buffer);
948 else if (fl.rcpt_smtp_response_same &&
949 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
950 fl.rcpt_smtp_response_same = FALSE;
951 fl.rcpt_in_progress = FALSE;
954 /* Now write the string */
958 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
960 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
962 smtp_write_error = -1;
967 /*************************************************
968 * Flush SMTP out and check for error *
969 *************************************************/
971 /* This function isn't currently used within Exim (it detects errors when it
972 tries to read the next SMTP input), but is available for use in local_scan().
973 It flushes the output and checks for errors.
976 Returns: 0 for no error; -1 after an error
982 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
986 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
988 (fflush(smtp_out) != 0)
990 smtp_write_error = -1;
992 return smtp_write_error;
997 /*************************************************
998 * SMTP command read timeout *
999 *************************************************/
1001 /* Signal handler for timing out incoming SMTP commands. This attempts to
1004 Argument: signal number (SIGALRM)
1009 command_timeout_handler(int sig)
1011 had_command_timeout = sig;
1016 /*************************************************
1017 * SIGTERM received *
1018 *************************************************/
1020 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1022 Argument: signal number (SIGTERM)
1027 command_sigterm_handler(int sig)
1029 had_command_sigterm = sig;
1035 #ifdef SUPPORT_PROXY
1036 /*************************************************
1037 * Restore socket timeout to previous value *
1038 *************************************************/
1039 /* If the previous value was successfully retrieved, restore
1040 it before returning control to the non-proxy routines
1042 Arguments: fd - File descriptor for input
1043 get_ok - Successfully retrieved previous values
1044 tvtmp - Time struct with previous values
1045 vslen - Length of time struct
1049 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1052 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1055 /*************************************************
1056 * Check if host is required proxy host *
1057 *************************************************/
1058 /* The function determines if inbound host will be a regular smtp host
1059 or if it is configured that it must use Proxy Protocol. A local
1067 check_proxy_protocol_host()
1071 if ( sender_host_address
1072 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1073 sender_host_address, NULL)) == OK)
1076 debug_printf("Detected proxy protocol configured host\n");
1077 proxy_session = TRUE;
1079 return proxy_session;
1083 /*************************************************
1084 * Read data until newline or end of buffer *
1085 *************************************************/
1086 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1087 read an entire buffer and assume there will be nothing past a proxy protocol
1088 header. Our approach normally is to use stdio, but again that relies upon
1089 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1090 reading _nothing_ before client TLS handshake. So we don't want to use the
1091 usual buffering reads which may read enough to block TLS starting.
1093 So unfortunately we're down to "read one byte at a time, with a syscall each,
1094 and expect a little overhead", for all proxy-opened connections which are v1,
1095 just to handle the TLS-on-connect case. Since SSL functions wrap the
1096 underlying fd, we can't assume that we can feed them any already-read content.
1098 We need to know where to read to, the max capacity, and we'll read until we
1099 get a CR and one more character. Let the caller scream if it's CR+!LF.
1101 Return the amount read.
1105 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1107 uschar *to = base + already;
1113 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1114 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1116 cr = memchr(base, '\r', already);
1119 if ((cr - base) < already - 1)
1121 /* \r and presumed \n already within what we have; probably not
1122 actually proxy protocol, but abort cleanly. */
1125 /* \r is last character read, just need one more. */
1129 while (capacity > 0)
1131 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1143 /* reached end without having room for a final newline, abort */
1148 /*************************************************
1149 * Setup host for proxy protocol *
1150 *************************************************/
1151 /* The function configures the connection based on a header from the
1152 inbound host to use Proxy Protocol. The specification is very exact
1153 so exit with an error if do not find the exact required pieces. This
1154 includes an incorrect number of spaces separating args.
1157 Returns: Boolean success
1161 setup_proxy_protocol_host()
1173 struct { /* TCP/UDP over IPv4, len = 12 */
1179 struct { /* TCP/UDP over IPv6, len = 36 */
1180 uint8_t src_addr[16];
1181 uint8_t dst_addr[16];
1185 struct { /* AF_UNIX sockets, len = 216 */
1186 uschar src_addr[108];
1187 uschar dst_addr[108];
1193 /* Temp variables used in PPv2 address:port parsing */
1195 char tmpip[INET_ADDRSTRLEN];
1196 struct sockaddr_in tmpaddr;
1197 char tmpip6[INET6_ADDRSTRLEN];
1198 struct sockaddr_in6 tmpaddr6;
1200 /* We can't read "all data until end" because while SMTP is
1201 server-speaks-first, the TLS handshake is client-speaks-first, so for
1202 TLS-on-connect ports the proxy protocol header will usually be immediately
1203 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1204 reinject data for reading by those. So instead we first read "enough to be
1205 safely read within the header, and figure out how much more to read".
1206 For v1 we will later read to the end-of-line, for v2 we will read based upon
1209 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1210 data is needed total. For v1, where the line looks like:
1211 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1213 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1214 We seem to support that. So, if we read 14 octets then we can tell if we're
1215 v2 or v1. If we're v1, we can continue reading as normal.
1217 If we're v2, we can't slurp up the entire header. We need the length in the
1218 15th & 16th octets, then to read everything after that.
1220 So to safely handle v1 and v2, with client-sent-first supported correctly,
1221 we have to do a minimum of 3 read calls, not 1. Eww.
1224 #define PROXY_INITIAL_READ 14
1225 #define PROXY_V2_HEADER_SIZE 16
1226 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1227 # error Code bug in sizes of data to read for proxy usage
1232 int fd = fileno(smtp_in);
1233 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1234 uschar * iptype; /* To display debug info */
1236 struct timeval tvtmp;
1237 socklen_t vslen = sizeof(struct timeval);
1240 /* Save current socket timeout values */
1241 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1243 /* Proxy Protocol host must send header within a short time
1244 (default 3 seconds) or it's considered invalid */
1245 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1246 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1247 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1252 /* The inbound host was declared to be a Proxy Protocol host, so
1253 don't do a PEEK into the data, actually slurp up enough to be
1254 "safe". Can't take it all because TLS-on-connect clients follow
1255 immediately with TLS handshake. */
1256 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1258 while (ret == -1 && errno == EINTR);
1263 /* For v2, handle reading the length, and then the rest. */
1264 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1269 /* First get the length fields. */
1272 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1273 } while (retmore == -1 && errno == EINTR);
1278 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1280 /* May 2014: haproxy combined the version and command into one byte to
1281 allow two full bytes for the length field in order to proxy SSL
1282 connections. SSL Proxy is not supported in this version of Exim, but
1283 must still separate values here. */
1287 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1291 /* The v2 header will always be 16 bytes per the spec. */
1292 size = 16 + ntohs(hdr.v2.len);
1293 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1294 size, (int)sizeof(hdr));
1296 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1297 amount that we need. Double-check that the size is not unreasonable, then
1299 if (size > sizeof(hdr))
1301 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1309 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1310 } while (retmore == -1 && errno == EINTR);
1314 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1315 } while (ret < size);
1317 } /* end scope for getting rest of data for v2 */
1319 /* At this point: if PROXYv2, we've read the exact size required for all data;
1320 if PROXYv1 then we've read "less than required for any valid line" and should
1323 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1325 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1329 case 0x01: /* PROXY command */
1332 case 0x11: /* TCPv4 address type */
1334 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1335 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1336 if (!string_is_ip_address(US tmpip, NULL))
1338 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1341 proxy_local_address = sender_host_address;
1342 sender_host_address = string_copy(US tmpip);
1343 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1344 proxy_local_port = sender_host_port;
1345 sender_host_port = tmpport;
1346 /* Save dest ip/port */
1347 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1348 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1349 if (!string_is_ip_address(US tmpip, NULL))
1351 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1354 proxy_external_address = string_copy(US tmpip);
1355 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1356 proxy_external_port = tmpport;
1358 case 0x21: /* TCPv6 address type */
1360 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1361 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1362 if (!string_is_ip_address(US tmpip6, NULL))
1364 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1367 proxy_local_address = sender_host_address;
1368 sender_host_address = string_copy(US tmpip6);
1369 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1370 proxy_local_port = sender_host_port;
1371 sender_host_port = tmpport;
1372 /* Save dest ip/port */
1373 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1374 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1375 if (!string_is_ip_address(US tmpip6, NULL))
1377 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1380 proxy_external_address = string_copy(US tmpip6);
1381 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1382 proxy_external_port = tmpport;
1386 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1390 /* Unsupported protocol, keep local connection address */
1392 case 0x00: /* LOCAL command */
1393 /* Keep local connection address for LOCAL */
1398 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1402 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1406 uschar *sp; /* Utility variables follow */
1411 /* get the rest of the line */
1412 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1417 p = string_copy(hdr.v1.line);
1418 end = memchr(p, '\r', ret - 1);
1420 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1422 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1425 *end = '\0'; /* Terminate the string */
1426 size = end + 2 - p; /* Skip header + CRLF */
1427 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1428 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1429 /* Step through the string looking for the required fields. Ensure
1430 strict adherence to required formatting, exit for any error. */
1432 if (!isspace(*(p++)))
1434 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1437 if (!Ustrncmp(p, CCS"TCP4", 4))
1439 else if (!Ustrncmp(p,CCS"TCP6", 4))
1441 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1443 iptype = US"Unknown";
1448 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1452 p += Ustrlen(iptype);
1453 if (!isspace(*(p++)))
1455 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1458 /* Find the end of the arg */
1459 if ((sp = Ustrchr(p, ' ')) == NULL)
1462 debug_printf("Did not find proxied src %s\n", iptype);
1466 if(!string_is_ip_address(p, NULL))
1469 debug_printf("Proxied src arg is not an %s address\n", iptype);
1472 proxy_local_address = sender_host_address;
1473 sender_host_address = p;
1475 if ((sp = Ustrchr(p, ' ')) == NULL)
1478 debug_printf("Did not find proxy dest %s\n", iptype);
1482 if(!string_is_ip_address(p, NULL))
1485 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1488 proxy_external_address = p;
1490 if ((sp = Ustrchr(p, ' ')) == NULL)
1492 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1496 tmp_port = strtol(CCS p, &endc, 10);
1497 if (*endc || tmp_port == 0)
1500 debug_printf("Proxied src port '%s' not an integer\n", p);
1503 proxy_local_port = sender_host_port;
1504 sender_host_port = tmp_port;
1506 if ((sp = Ustrchr(p, '\0')) == NULL)
1508 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1511 tmp_port = strtol(CCS p, &endc, 10);
1512 if (*endc || tmp_port == 0)
1515 debug_printf("Proxy dest port '%s' not an integer\n", p);
1518 proxy_external_port = tmp_port;
1519 /* Already checked for /r /n above. Good V1 header received. */
1523 /* Wrong protocol */
1524 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1525 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1531 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1532 yield = proxy_session;
1534 /* Don't flush any potential buffer contents. Any input on proxyfail
1535 should cause a synchronization failure */
1538 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1543 sender_host_name = NULL;
1544 (void) host_name_lookup();
1545 host_build_sender_fullhost();
1549 f.proxy_session_failed = TRUE;
1551 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1558 /*************************************************
1559 * Read one command line *
1560 *************************************************/
1562 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1563 There are sites that don't do this, and in any case internal SMTP probably
1564 should check only for LF. Consequently, we check here for LF only. The line
1565 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1566 an unknown command. The command is read into the global smtp_cmd_buffer so that
1567 it is available via $smtp_command.
1569 The character reading routine sets up a timeout for each block actually read
1570 from the input (which may contain more than one command). We set up a special
1571 signal handler that closes down the session on a timeout. Control does not
1572 return when it runs.
1575 check_sync if TRUE, check synchronization rules if global option is TRUE
1576 buffer_lim maximum to buffer in lower layer
1578 Returns: a code identifying the command (enumerated above)
1582 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1586 BOOL hadnull = FALSE;
1588 had_command_timeout = 0;
1589 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1591 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1593 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1595 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1603 smtp_cmd_buffer[ptr++] = c;
1606 receive_linecount++; /* For BSMTP errors */
1607 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1609 /* If hit end of file, return pseudo EOF command. Whether we have a
1610 part-line already read doesn't matter, since this is an error state. */
1612 if (c == EOF) return EOF_CMD;
1614 /* Remove any CR and white space at the end of the line, and terminate the
1617 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1618 smtp_cmd_buffer[ptr] = 0;
1620 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1622 /* NULLs are not allowed in SMTP commands */
1624 if (hadnull) return BADCHAR_CMD;
1626 /* Scan command list and return identity, having set the data pointer
1627 to the start of the actual data characters. Check for SMTP synchronization
1630 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1632 #ifdef SUPPORT_PROXY
1633 /* Only allow QUIT command if Proxy Protocol parsing failed */
1634 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1638 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1639 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1640 || smtp_cmd_buffer[p->len] == 0
1641 || smtp_cmd_buffer[p->len] == ' '
1644 if (smtp_inptr < smtp_inend && /* Outstanding input */
1645 p->cmd < sync_cmd_limit && /* Command should sync */
1646 check_sync && /* Local flag set */
1647 smtp_enforce_sync && /* Global flag set */
1648 sender_host_address != NULL && /* Not local input */
1649 !f.sender_host_notsocket) /* Really is a socket */
1652 /* The variables $smtp_command and $smtp_command_argument point into the
1653 unmodified input buffer. A copy of the latter is taken for actual
1654 processing, so that it can be chopped up into separate parts if necessary,
1655 for example, when processing a MAIL command options such as SIZE that can
1656 follow the sender address. */
1658 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1659 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1660 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1661 smtp_cmd_data = smtp_data_buffer;
1663 /* Count non-mail commands from those hosts that are controlled in this
1664 way. The default is all hosts. We don't waste effort checking the list
1665 until we get a non-mail command, but then cache the result to save checking
1666 again. If there's a DEFER while checking the host, assume it's in the list.
1668 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1669 start of each incoming message by fiddling with the value in the table. */
1671 if (!p->is_mail_cmd)
1673 if (count_nonmail == TRUE_UNSET) count_nonmail =
1674 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1675 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1676 return TOO_MANY_NONMAIL_CMD;
1679 /* If there is data for a command that does not expect it, generate the
1682 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1686 #ifdef SUPPORT_PROXY
1687 /* Only allow QUIT command if Proxy Protocol parsing failed */
1688 if (proxy_session && f.proxy_session_failed)
1689 return PROXY_FAIL_IGNORE_CMD;
1692 /* Enforce synchronization for unknown commands */
1694 if ( smtp_inptr < smtp_inend /* Outstanding input */
1695 && check_sync /* Local flag set */
1696 && smtp_enforce_sync /* Global flag set */
1697 && sender_host_address /* Not local input */
1698 && !f.sender_host_notsocket) /* Really is a socket */
1706 /*************************************************
1707 * Forced closedown of call *
1708 *************************************************/
1710 /* This function is called from log.c when Exim is dying because of a serious
1711 disaster, and also from some other places. If an incoming non-batched SMTP
1712 channel is open, it swallows the rest of the incoming message if in the DATA
1713 phase, sends the reply string, and gives an error to all subsequent commands
1714 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1718 message SMTP reply string to send, excluding the code
1724 smtp_closedown(uschar *message)
1726 if (!smtp_in || smtp_batched_input) return;
1727 receive_swallow_smtp();
1728 smtp_printf("421 %s\r\n", FALSE, message);
1730 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1736 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1741 smtp_printf("250 Reset OK\r\n", FALSE);
1745 smtp_printf("421 %s\r\n", FALSE, message);
1753 /*************************************************
1754 * Set up connection info for logging *
1755 *************************************************/
1757 /* This function is called when logging information about an SMTP connection.
1758 It sets up appropriate source information, depending on the type of connection.
1759 If sender_fullhost is NULL, we are at a very early stage of the connection;
1760 just use the IP address.
1763 Returns: a string describing the connection
1767 smtp_get_connection_info(void)
1769 const uschar * hostname = sender_fullhost
1770 ? sender_fullhost : sender_host_address;
1773 return string_sprintf("SMTP connection from %s", hostname);
1775 if (f.sender_host_unknown || f.sender_host_notsocket)
1776 return string_sprintf("SMTP connection from %s", sender_ident);
1779 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1781 if (LOGGING(incoming_interface) && interface_address)
1782 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1783 interface_address, interface_port);
1785 return string_sprintf("SMTP connection from %s", hostname);
1791 /* Append TLS-related information to a log line
1794 g String under construction: allocated string to extend, or NULL
1796 Returns: Allocated string or NULL
1799 s_tlslog(gstring * g)
1801 if (LOGGING(tls_cipher) && tls_in.cipher)
1803 g = string_append(g, 2, US" X=", tls_in.cipher);
1804 #ifndef DISABLE_TLS_RESUME
1805 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1806 g = string_catn(g, US"*", 1);
1809 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1810 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1811 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1812 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1813 if (LOGGING(tls_sni) && tls_in.sni)
1814 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1819 /*************************************************
1820 * Log lack of MAIL if so configured *
1821 *************************************************/
1823 /* This function is called when an SMTP session ends. If the log selector
1824 smtp_no_mail is set, write a log line giving some details of what has happened
1825 in the SMTP session.
1832 smtp_log_no_mail(void)
1837 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1840 if (sender_host_authenticated)
1842 g = string_append(g, 2, US" A=", sender_host_authenticated);
1843 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1850 sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1852 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1853 if (smtp_connection_had[i] != SCH_NONE)
1855 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1859 for (int i = 0; i < smtp_ch_index; i++)
1861 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1865 if (!(s = string_from_gstring(g))) s = US"";
1867 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1868 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1869 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1873 /* Return list of recent smtp commands */
1878 gstring * list = NULL;
1881 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1882 if (smtp_connection_had[i] != SCH_NONE)
1883 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1885 for (int i = 0; i < smtp_ch_index; i++)
1886 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1888 s = string_from_gstring(list);
1889 return s ? s : US"";
1895 /*************************************************
1896 * Check HELO line and set sender_helo_name *
1897 *************************************************/
1899 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1900 the domain name of the sending host, or an ip literal in square brackets. The
1901 argument is placed in sender_helo_name, which is in malloc store, because it
1902 must persist over multiple incoming messages. If helo_accept_junk is set, this
1903 host is permitted to send any old junk (needed for some broken hosts).
1904 Otherwise, helo_allow_chars can be used for rogue characters in general
1905 (typically people want to let in underscores).
1908 s the data portion of the line (already past any white space)
1910 Returns: TRUE or FALSE
1914 check_helo(uschar *s)
1917 uschar *end = s + Ustrlen(s);
1918 BOOL yield = fl.helo_accept_junk;
1920 /* Discard any previous helo name */
1922 sender_helo_name = NULL;
1924 /* Skip tests if junk is permitted. */
1928 /* Allow the new standard form for IPv6 address literals, namely,
1929 [IPv6:....], and because someone is bound to use it, allow an equivalent
1930 IPv4 form. Allow plain addresses as well. */
1937 if (strncmpic(s, US"[IPv6:", 6) == 0)
1938 yield = (string_is_ip_address(s+6, NULL) == 6);
1939 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1940 yield = (string_is_ip_address(s+6, NULL) == 4);
1942 yield = (string_is_ip_address(s+1, NULL) != 0);
1947 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1948 that have been configured (usually underscore - sigh). */
1951 for (yield = TRUE; *s; s++)
1952 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1953 Ustrchr(helo_allow_chars, *s) == NULL)
1959 /* Save argument if OK */
1961 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
1969 /*************************************************
1970 * Extract SMTP command option *
1971 *************************************************/
1973 /* This function picks the next option setting off the end of smtp_cmd_data. It
1974 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1975 things that can appear there.
1978 name point this at the name
1979 value point this at the data string
1981 Returns: TRUE if found an option
1985 extract_option(uschar **name, uschar **value)
1988 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1989 while (isspace(*v)) v--;
1991 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1993 /* Take care to not stop at a space embedded in a quoted local-part */
1995 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
2002 while(isalpha(n[-1])) n--;
2003 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2004 if (!isspace(n[-1])) return FALSE;
2010 if (v == smtp_cmd_data) return FALSE;
2022 /*************************************************
2023 * Reset for new message *
2024 *************************************************/
2026 /* This function is called whenever the SMTP session is reset from
2027 within either of the setup functions; also from the daemon loop.
2029 Argument: the stacking pool storage reset point
2034 smtp_reset(void *reset_point)
2036 recipients_list = NULL;
2037 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2038 raw_recipients_count = recipients_count = recipients_list_max = 0;
2039 message_linecount = 0;
2041 acl_added_headers = NULL;
2042 acl_removed_headers = NULL;
2043 f.queue_only_policy = FALSE;
2044 rcpt_smtp_response = NULL;
2045 fl.rcpt_smtp_response_same = TRUE;
2046 fl.rcpt_in_progress = FALSE;
2047 f.deliver_freeze = FALSE; /* Can be set by ACL */
2048 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2049 fake_response = OK; /* Can be set by ACL */
2050 #ifdef WITH_CONTENT_SCAN
2051 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2053 f.submission_mode = FALSE; /* Can be set by ACL */
2054 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2055 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2056 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2057 sending_ip_address = NULL;
2058 return_path = sender_address = NULL;
2059 deliver_localpart_data = deliver_domain_data =
2060 recipient_data = sender_data = NULL; /* Can be set by ACL */
2061 recipient_verify_failure = NULL;
2062 deliver_localpart_parent = deliver_localpart_orig = NULL;
2063 deliver_domain_parent = deliver_domain_orig = NULL;
2064 callout_address = NULL;
2065 submission_name = NULL; /* Can be set by ACL */
2066 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2067 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2068 sender_verified_list = NULL; /* No senders verified */
2069 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2070 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2072 authenticated_sender = NULL;
2073 #ifdef EXPERIMENTAL_BRIGHTMAIL
2075 bmi_verdicts = NULL;
2077 dnslist_domain = dnslist_matched = NULL;
2079 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2080 spf_result_guessed = FALSE;
2082 #ifndef DISABLE_DKIM
2083 dkim_cur_signer = dkim_signers =
2084 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2085 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2086 f.dkim_disable_verify = FALSE;
2087 dkim_collect_input = 0;
2088 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2089 dkim_key_length = 0;
2091 #ifdef SUPPORT_DMARC
2092 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2093 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2094 dmarc_used_domain = NULL;
2096 #ifdef EXPERIMENTAL_ARC
2097 arc_state = arc_state_reason = NULL;
2098 arc_received_instance = 0;
2102 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2103 #ifndef DISABLE_PRDR
2104 prdr_requested = FALSE;
2107 message_smtputf8 = FALSE;
2109 body_linecount = body_zerocount = 0;
2111 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2112 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2113 /* Note that ratelimiters_conn persists across resets. */
2115 /* Reset message ACL variables */
2119 /* The message body variables use malloc store. They may be set if this is
2120 not the first message in an SMTP session and the previous message caused them
2121 to be referenced in an ACL. */
2125 store_free(message_body);
2126 message_body = NULL;
2129 if (message_body_end)
2131 store_free(message_body_end);
2132 message_body_end = NULL;
2135 /* Warning log messages are also saved in malloc store. They are saved to avoid
2136 repetition in the same message, but it seems right to repeat them for different
2139 while (acl_warn_logged)
2141 string_item *this = acl_warn_logged;
2142 acl_warn_logged = acl_warn_logged->next;
2145 store_reset(reset_point);
2146 return store_mark();
2153 /*************************************************
2154 * Initialize for incoming batched SMTP message *
2155 *************************************************/
2157 /* This function is called from smtp_setup_msg() in the case when
2158 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2159 of messages in one file with SMTP commands between them. All errors must be
2160 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2161 relevant. After an error on a sender, or an invalid recipient, the remainder
2162 of the message is skipped. The value of received_protocol is already set.
2165 Returns: > 0 message successfully started (reached DATA)
2166 = 0 QUIT read or end of file reached
2167 < 0 should not occur
2171 smtp_setup_batch_msg(void)
2174 rmark reset_point = store_mark();
2176 /* Save the line count at the start of each transaction - single commands
2177 like HELO and RSET count as whole transactions. */
2179 bsmtp_transaction_linecount = receive_linecount;
2181 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2183 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2184 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2186 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2187 value. The values are 2 larger than the required yield of the function. */
2192 uschar *recipient = NULL;
2193 int start, end, sender_domain, recipient_domain;
2195 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2197 /* The HELO/EHLO commands set sender_address_helo if they have
2198 valid data; otherwise they are ignored, except that they do
2199 a reset of the state. */
2204 check_helo(smtp_cmd_data);
2208 cancel_cutthrough_connection(TRUE, US"RSET received");
2209 reset_point = smtp_reset(reset_point);
2210 bsmtp_transaction_linecount = receive_linecount;
2214 /* The MAIL FROM command requires an address as an operand. All we
2215 do here is to parse it for syntactic correctness. The form "<>" is
2216 a special case which converts into an empty string. The start/end
2217 pointers in the original are not used further for this address, as
2218 it is the canonical extracted address which is all that is kept. */
2221 smtp_mailcmd_count++; /* Count for no-mail log */
2222 if (sender_address != NULL)
2223 /* The function moan_smtp_batch() does not return. */
2224 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2226 if (smtp_cmd_data[0] == 0)
2227 /* The function moan_smtp_batch() does not return. */
2228 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2230 /* Reset to start of message */
2232 cancel_cutthrough_connection(TRUE, US"MAIL received");
2233 reset_point = smtp_reset(reset_point);
2235 /* Apply SMTP rewrite */
2237 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2238 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2239 US"", global_rewrite_rules) : smtp_cmd_data;
2241 /* Extract the address; the TRUE flag allows <> as valid */
2244 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2248 /* The function moan_smtp_batch() does not return. */
2249 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2251 sender_address = string_copy(raw_sender);
2253 /* Qualify unqualified sender addresses if permitted to do so. */
2256 && sender_address[0] != 0 && sender_address[0] != '@')
2257 if (f.allow_unqualified_sender)
2259 sender_address = rewrite_address_qualify(sender_address, FALSE);
2260 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2261 "and rewritten\n", raw_sender);
2263 /* The function moan_smtp_batch() does not return. */
2265 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2270 /* The RCPT TO command requires an address as an operand. All we do
2271 here is to parse it for syntactic correctness. There may be any number
2272 of RCPT TO commands, specifying multiple senders. We build them all into
2273 a data structure that is in argc/argv format. The start/end values
2274 given by parse_extract_address are not used, as we keep only the
2275 extracted address. */
2278 if (!sender_address)
2279 /* The function moan_smtp_batch() does not return. */
2280 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2282 if (smtp_cmd_data[0] == 0)
2283 /* The function moan_smtp_batch() does not return. */
2284 moan_smtp_batch(smtp_cmd_buffer,
2285 "501 RCPT TO must have an address operand");
2287 /* Check maximum number allowed */
2289 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2290 /* The function moan_smtp_batch() does not return. */
2291 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2292 recipients_max_reject? "552": "452");
2294 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2295 recipient address */
2297 recipient = rewrite_existflags & rewrite_smtp
2298 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2299 global_rewrite_rules)
2302 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2303 &recipient_domain, FALSE);
2306 /* The function moan_smtp_batch() does not return. */
2307 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2309 /* If the recipient address is unqualified, qualify it if permitted. Then
2310 add it to the list of recipients. */
2312 if (!recipient_domain)
2313 if (f.allow_unqualified_recipient)
2315 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2317 recipient = rewrite_address_qualify(recipient, TRUE);
2319 /* The function moan_smtp_batch() does not return. */
2321 moan_smtp_batch(smtp_cmd_buffer,
2322 "501 recipient address must contain a domain");
2324 receive_add_recipient(recipient, -1);
2328 /* The DATA command is legal only if it follows successful MAIL FROM
2329 and RCPT TO commands. This function is complete when a valid DATA
2330 command is encountered. */
2333 if (!sender_address || recipients_count <= 0)
2334 /* The function moan_smtp_batch() does not return. */
2335 if (!sender_address)
2336 moan_smtp_batch(smtp_cmd_buffer,
2337 "503 MAIL FROM:<sender> command must precede DATA");
2339 moan_smtp_batch(smtp_cmd_buffer,
2340 "503 RCPT TO:<recipient> must precede DATA");
2343 done = 3; /* DATA successfully achieved */
2344 message_ended = END_NOTENDED; /* Indicate in middle of message */
2349 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2356 bsmtp_transaction_linecount = receive_linecount;
2367 /* The function moan_smtp_batch() does not return. */
2368 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2373 /* The function moan_smtp_batch() does not return. */
2374 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2379 /* The function moan_smtp_batch() does not return. */
2380 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2385 return done - 2; /* Convert yield values */
2393 smtp_log_tls_fail(uschar * errstr)
2395 uschar * conn_info = smtp_get_connection_info();
2397 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2398 /* I'd like to get separated H= here, but too hard for now */
2400 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2414 socklen_t len = sizeof(is_fastopen);
2416 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2417 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2419 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2424 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2425 f.tcp_in_fastopen = TRUE;
2428 else DEBUG(D_receive)
2429 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2431 # elif defined(TCP_INFO)
2432 struct tcp_info tinfo;
2433 socklen_t len = sizeof(tinfo);
2435 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2436 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2437 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2440 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2441 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2445 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2448 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2449 f.tcp_in_fastopen = TRUE;
2451 else DEBUG(D_receive)
2452 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2458 /*************************************************
2459 * Start an SMTP session *
2460 *************************************************/
2462 /* This function is called at the start of an SMTP session. Thereafter,
2463 smtp_setup_msg() is called to initiate each separate message. This
2464 function does host-specific testing, and outputs the banner line.
2467 Returns: FALSE if the session can not continue; something has
2468 gone wrong, or the connection to the host is blocked
2472 smtp_start_session(void)
2475 uschar *user_msg, *log_msg;
2480 gettimeofday(&smtp_connection_start, NULL);
2481 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2482 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2485 /* Default values for certain variables */
2487 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2488 smtp_mailcmd_count = 0;
2489 count_nonmail = TRUE_UNSET;
2490 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2491 smtp_delay_mail = smtp_rlm_base;
2492 fl.auth_advertised = FALSE;
2493 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2494 f.pipelining_enable = TRUE;
2495 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2496 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2498 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2499 authentication settings from -oMaa to remain in force. */
2501 if (!host_checking && !f.sender_host_notsocket)
2502 sender_host_auth_pubname = sender_host_authenticated = NULL;
2503 authenticated_by = NULL;
2506 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2507 tls_in.ourcert = tls_in.peercert = NULL;
2509 tls_in.ocsp = OCSP_NOT_REQ;
2510 fl.tls_advertised = FALSE;
2512 fl.dsn_advertised = FALSE;
2514 fl.smtputf8_advertised = FALSE;
2517 /* Reset ACL connection variables */
2521 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2523 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, TRUE);
2525 smtp_cmd_buffer[0] = 0;
2526 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2528 /* For batched input, the protocol setting can be overridden from the
2529 command line by a trusted caller. */
2531 if (smtp_batched_input)
2533 if (!received_protocol) received_protocol = US"local-bsmtp";
2536 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2537 reset later if any of EHLO/AUTH/STARTTLS are received. */
2541 (sender_host_address ? protocols : protocols_local) [pnormal];
2543 /* Set up the buffer for inputting using direct read() calls, and arrange to
2544 call the local functions instead of the standard C ones. Place a NUL at the
2545 end of the buffer to safety-stop C-string reads from it. */
2547 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2548 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2549 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2551 receive_getc = smtp_getc;
2552 receive_getbuf = smtp_getbuf;
2553 receive_get_cache = smtp_get_cache;
2554 receive_ungetc = smtp_ungetc;
2555 receive_feof = smtp_feof;
2556 receive_ferror = smtp_ferror;
2557 receive_smtp_buffered = smtp_buffered;
2558 smtp_inptr = smtp_inend = smtp_inbuffer;
2559 smtp_had_eof = smtp_had_error = 0;
2561 /* Set up the message size limit; this may be host-specific */
2563 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2564 if (expand_string_message)
2566 if (thismessage_size_limit == -1)
2567 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2568 "%s", expand_string_message);
2570 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2571 "%s", expand_string_message);
2572 smtp_closedown(US"Temporary local problem - please try later");
2576 /* When a message is input locally via the -bs or -bS options, sender_host_
2577 unknown is set unless -oMa was used to force an IP address, in which case it
2578 is checked like a real remote connection. When -bs is used from inetd, this
2579 flag is not set, causing the sending host to be checked. The code that deals
2580 with IP source routing (if configured) is never required for -bs or -bS and
2581 the flag sender_host_notsocket is used to suppress it.
2583 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2584 reserve for certain hosts and/or networks. */
2586 if (!f.sender_host_unknown)
2589 BOOL reserved_host = FALSE;
2591 /* Look up IP options (source routing info) on the socket if this is not an
2592 -oMa "host", and if any are found, log them and drop the connection.
2594 Linux (and others now, see below) is different to everyone else, so there
2595 has to be some conditional compilation here. Versions of Linux before 2.1.15
2596 used a structure whose name was "options". Somebody finally realized that
2597 this name was silly, and it got changed to "ip_options". I use the
2598 newer name here, but there is a fudge in the script that sets up os.h
2599 to define a macro in older Linux systems.
2601 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2602 glibc 2, which has chosen ip_opts for the structure name. This is now
2603 really a glibc thing rather than a Linux thing, so the condition name
2604 has been changed to reflect this. It is relevant also to GNU/Hurd.
2606 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2607 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2608 a special macro defined in the os.h file.
2610 Some DGUX versions on older hardware appear not to support IP options at
2611 all, so there is now a general macro which can be set to cut out this
2614 How to do this properly in IPv6 is not yet known. */
2616 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2618 #ifdef GLIBC_IP_OPTIONS
2619 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2624 #elif defined DARWIN_IP_OPTIONS
2630 if (!host_checking && !f.sender_host_notsocket)
2633 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2634 struct ip_options *ipopt = store_get(optlen, FALSE);
2636 struct ip_opts ipoptblock;
2637 struct ip_opts *ipopt = &ipoptblock;
2638 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2640 struct ipoption ipoptblock;
2641 struct ipoption *ipopt = &ipoptblock;
2642 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2645 /* Occasional genuine failures of getsockopt() have been seen - for
2646 example, "reset by peer". Therefore, just log and give up on this
2647 call, unless the error is ENOPROTOOPT. This error is given by systems
2648 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2649 of writing. So for that error, carry on - we just can't do an IP options
2652 DEBUG(D_receive) debug_printf("checking for IP options\n");
2654 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2657 if (errno != ENOPROTOOPT)
2659 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2660 host_and_ident(FALSE), strerror(errno));
2661 smtp_printf("451 SMTP service not available\r\n", FALSE);
2666 /* Deal with any IP options that are set. On the systems I have looked at,
2667 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2668 more logging data than will fit in big_buffer. Nevertheless, after somebody
2669 questioned this code, I've added in some paranoid checking. */
2671 else if (optlen > 0)
2673 uschar *p = big_buffer;
2674 uschar *pend = big_buffer + big_buffer_size;
2677 struct in_addr addr;
2680 uschar *optstart = US (ipopt->__data);
2682 uschar *optstart = US (ipopt->ip_opts);
2684 uschar *optstart = US (ipopt->ipopt_list);
2687 DEBUG(D_receive) debug_printf("IP options exist\n");
2689 Ustrcpy(p, "IP options on incoming call:");
2692 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2705 if (!string_format(p, pend-p, " %s [@%s",
2706 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2708 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2710 inet_ntoa(ipopt->ip_dst)))
2712 inet_ntoa(ipopt->ipopt_dst)))
2720 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2722 while (optcount-- > 0)
2724 memcpy(&addr, adptr, sizeof(addr));
2725 if (!string_format(p, pend - p - 1, "%s%s",
2726 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2732 adptr += sizeof(struct in_addr);
2740 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2743 for (int i = 0; i < opt[1]; i++)
2744 p += sprintf(CS p, "%2.2x ", opt[i]);
2752 log_write(0, LOG_MAIN, "%s", big_buffer);
2754 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2756 log_write(0, LOG_MAIN|LOG_REJECT,
2757 "connection from %s refused (IP options)", host_and_ident(FALSE));
2759 smtp_printf("554 SMTP service not available\r\n", FALSE);
2763 /* Length of options = 0 => there are no options */
2765 else DEBUG(D_receive) debug_printf("no IP options found\n");
2767 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2769 /* Set keep-alive in socket options. The option is on by default. This
2770 setting is an attempt to get rid of some hanging connections that stick in
2771 read() when the remote end (usually a dialup) goes away. */
2773 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2774 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2776 /* If the current host matches host_lookup, set the name by doing a
2777 reverse lookup. On failure, sender_host_name will be NULL and
2778 host_lookup_failed will be TRUE. This may or may not be serious - optional
2781 if (verify_check_host(&host_lookup) == OK)
2783 (void)host_name_lookup();
2784 host_build_sender_fullhost();
2787 /* Delay this until we have the full name, if it is looked up. */
2789 set_process_info("handling incoming connection from %s",
2790 host_and_ident(FALSE));
2792 /* Expand smtp_receive_timeout, if needed */
2794 if (smtp_receive_timeout_s)
2797 if ( !(exp = expand_string(smtp_receive_timeout_s))
2799 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2801 log_write(0, LOG_MAIN|LOG_PANIC,
2802 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2805 /* Test for explicit connection rejection */
2807 if (verify_check_host(&host_reject_connection) == OK)
2809 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2810 "from %s (host_reject_connection)", host_and_ident(FALSE));
2811 smtp_printf("554 SMTP service not available\r\n", FALSE);
2815 /* Test with TCP Wrappers if so configured. There is a problem in that
2816 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2817 such as disks dying. In these cases, it is desirable to reject with a 4xx
2818 error instead of a 5xx error. There isn't a "right" way to detect such
2819 problems. The following kludge is used: errno is zeroed before calling
2820 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2821 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2824 #ifdef USE_TCP_WRAPPERS
2826 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2827 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2828 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2829 expand_string_message);
2831 if (!hosts_ctl(tcp_wrappers_name,
2832 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2833 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2834 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2836 if (errno == 0 || errno == ENOENT)
2838 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2839 log_write(L_connection_reject,
2840 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2841 "(tcp wrappers)", host_and_ident(FALSE));
2842 smtp_printf("554 SMTP service not available\r\n", FALSE);
2846 int save_errno = errno;
2847 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2848 "errno value %d\n", save_errno);
2849 log_write(L_connection_reject,
2850 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2851 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2852 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2858 /* Check for reserved slots. The value of smtp_accept_count has already been
2859 incremented to include this process. */
2861 if (smtp_accept_max > 0 &&
2862 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2864 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2866 log_write(L_connection_reject,
2867 LOG_MAIN, "temporarily refused connection from %s: not in "
2868 "reserve list: connected=%d max=%d reserve=%d%s",
2869 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2870 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2871 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2872 "please try again later\r\n", FALSE, smtp_active_hostname);
2875 reserved_host = TRUE;
2878 /* If a load level above which only messages from reserved hosts are
2879 accepted is set, check the load. For incoming calls via the daemon, the
2880 check is done in the superior process if there are no reserved hosts, to
2881 save a fork. In all cases, the load average will already be available
2882 in a global variable at this point. */
2884 if (smtp_load_reserve >= 0 &&
2885 load_average > smtp_load_reserve &&
2887 verify_check_host(&smtp_reserve_hosts) != OK)
2889 log_write(L_connection_reject,
2890 LOG_MAIN, "temporarily refused connection from %s: not in "
2891 "reserve list and load average = %.2f", host_and_ident(FALSE),
2892 (double)load_average/1000.0);
2893 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2894 smtp_active_hostname);
2898 /* Determine whether unqualified senders or recipients are permitted
2899 for this host. Unfortunately, we have to do this every time, in order to
2900 set the flags so that they can be inspected when considering qualifying
2901 addresses in the headers. For a site that permits no qualification, this
2902 won't take long, however. */
2904 f.allow_unqualified_sender =
2905 verify_check_host(&sender_unqualified_hosts) == OK;
2907 f.allow_unqualified_recipient =
2908 verify_check_host(&recipient_unqualified_hosts) == OK;
2910 /* Determine whether HELO/EHLO is required for this host. The requirement
2911 can be hard or soft. */
2913 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2914 if (!fl.helo_required)
2915 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2917 /* Determine whether this hosts is permitted to send syntactic junk
2918 after a HELO or EHLO command. */
2920 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2923 /* For batch SMTP input we are now done. */
2925 if (smtp_batched_input) return TRUE;
2927 /* If valid Proxy Protocol source is connecting, set up session.
2928 * Failure will not allow any SMTP function other than QUIT. */
2930 #ifdef SUPPORT_PROXY
2931 proxy_session = FALSE;
2932 f.proxy_session_failed = FALSE;
2933 if (check_proxy_protocol_host())
2934 setup_proxy_protocol_host();
2937 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2938 smtps port for use with older style SSL MTAs. */
2941 if (tls_in.on_connect)
2943 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2944 return smtp_log_tls_fail(user_msg);
2945 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2949 /* Run the connect ACL if it exists */
2952 if (acl_smtp_connect)
2955 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2958 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2963 /* Output the initial message for a two-way SMTP connection. It may contain
2964 newlines, which then cause a multi-line response to be given. */
2966 code = US"220"; /* Default status code */
2967 esc = US""; /* Default extended status code */
2968 esclen = 0; /* Length of esc */
2972 if (!(s = expand_string(smtp_banner)))
2973 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2974 "failed: %s", smtp_banner, expand_string_message);
2980 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2984 esclen = codelen - 4;
2988 /* Remove any terminating newlines; might as well remove trailing space too */
2991 while (p > s && isspace(p[-1])) p--;
2994 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2995 is all contained in a single IP packet. The original code wrote out the
2996 greeting using several calls to fprint/fputc, and on busy servers this could
2997 cause it to be split over more than one packet - which caused CC:Mail to fall
2998 over when it got the second part of the greeting after sending its first
2999 command. Sigh. To try to avoid this, build the complete greeting message
3000 first, and output it in one fell swoop. This gives a better chance of it
3001 ending up as a single packet. */
3003 ss = string_get(256);
3006 do /* At least once, in case we have an empty string */
3009 uschar *linebreak = Ustrchr(p, '\n');
3010 ss = string_catn(ss, code, 3);
3014 ss = string_catn(ss, US" ", 1);
3018 len = linebreak - p;
3019 ss = string_catn(ss, US"-", 1);
3021 ss = string_catn(ss, esc, esclen);
3022 ss = string_catn(ss, p, len);
3023 ss = string_catn(ss, US"\r\n", 2);
3029 /* Before we write the banner, check that there is no input pending, unless
3030 this synchronisation check is disabled. */
3032 #ifndef DISABLE_PIPE_CONNECT
3033 fl.pipe_connect_acceptable =
3034 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3037 if (fl.pipe_connect_acceptable)
3038 f.smtp_in_early_pipe_used = TRUE;
3044 unsigned n = smtp_inend - smtp_inptr;
3045 if (n > 128) n = 128;
3047 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3048 "synchronization error (input sent without waiting for greeting): "
3049 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3050 string_printing(string_copyn(smtp_inptr, n)));
3051 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3055 /* Now output the banner */
3056 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3059 #ifndef DISABLE_PIPE_CONNECT
3060 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3064 string_from_gstring(ss));
3066 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3067 handshake arrived. If so we must have managed a TFO. */
3070 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3080 /*************************************************
3081 * Handle SMTP syntax and protocol errors *
3082 *************************************************/
3084 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3085 to do so. Then transmit the error response. The return value depends on the
3086 number of syntax and protocol errors in this SMTP session.
3089 type error type, given as a log flag bit
3090 code response code; <= 0 means don't send a response
3091 data data to reflect in the response (can be NULL)
3092 errmess the error message
3094 Returns: -1 limit of syntax/protocol errors NOT exceeded
3095 +1 limit of syntax/protocol errors IS exceeded
3097 These values fit in with the values of the "done" variable in the main
3098 processing loop in smtp_setup_msg(). */
3101 synprot_error(int type, int code, uschar *data, uschar *errmess)
3105 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3106 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3107 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3109 if (++synprot_error_count > smtp_max_synprot_errors)
3112 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3113 "syntax or protocol errors (last command was \"%s\")",
3114 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3119 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3120 data ? data : US"", data ? US": " : US"", errmess);
3122 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3131 /*************************************************
3132 * Send SMTP response, possibly multiline *
3133 *************************************************/
3135 /* There are, it seems, broken clients out there that cannot handle multiline
3136 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3137 output nothing for non-final calls, and only the first line for anything else.
3140 code SMTP code, may involve extended status codes
3141 codelen length of smtp code; if > 4 there's an ESC
3142 final FALSE if the last line isn't the final line
3143 msg message text, possibly containing newlines
3149 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3154 if (!final && f.no_multiline_responses) return;
3159 esclen = codelen - 4;
3162 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3163 have had the same. Note: this code is also present in smtp_printf(). It would
3164 be tidier to have it only in one place, but when it was added, it was easier to
3165 do it that way, so as not to have to mess with the code for the RCPT command,
3166 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3168 if (fl.rcpt_in_progress)
3170 if (rcpt_smtp_response == NULL)
3171 rcpt_smtp_response = string_copy(msg);
3172 else if (fl.rcpt_smtp_response_same &&
3173 Ustrcmp(rcpt_smtp_response, msg) != 0)
3174 fl.rcpt_smtp_response_same = FALSE;
3175 fl.rcpt_in_progress = FALSE;
3178 /* Now output the message, splitting it up into multiple lines if necessary.
3179 We only handle pipelining these responses as far as nonfinal/final groups,
3180 not the whole MAIL/RCPT/DATA response set. */
3184 uschar *nl = Ustrchr(msg, '\n');
3187 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3190 else if (nl[1] == 0 || f.no_multiline_responses)
3192 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3193 (int)(nl - msg), msg);
3198 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3200 Uskip_whitespace(&msg);
3208 /*************************************************
3209 * Parse user SMTP message *
3210 *************************************************/
3212 /* This function allows for user messages overriding the response code details
3213 by providing a suitable response code string at the start of the message
3214 user_msg. Check the message for starting with a response code and optionally an
3215 extended status code. If found, check that the first digit is valid, and if so,
3216 change the code pointer and length to use the replacement. An invalid code
3217 causes a panic log; in this case, if the log messages is the same as the user
3218 message, we must also adjust the value of the log message to show the code that
3219 is actually going to be used (the original one).
3221 This function is global because it is called from receive.c as well as within
3224 Note that the code length returned includes the terminating whitespace
3225 character, which is always included in the regex match.
3228 code SMTP code, may involve extended status codes
3229 codelen length of smtp code; if > 4 there's an ESC
3231 log_msg optional log message, to be adjusted with the new SMTP code
3232 check_valid if true, verify the response code
3238 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3244 if (!msg || !*msg) return;
3246 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3247 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3249 if (check_valid && (*msg)[0] != (*code)[0])
3251 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3252 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3253 if (log_msg != NULL && *log_msg == *msg)
3254 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3259 *codelen = ovector[1]; /* Includes final space */
3261 *msg += ovector[1]; /* Chop the code off the message */
3268 /*************************************************
3269 * Handle an ACL failure *
3270 *************************************************/
3272 /* This function is called when acl_check() fails. As well as calls from within
3273 this module, it is called from receive.c for an ACL after DATA. It sorts out
3274 logging the incident, and sends the error response. A message containing
3275 newlines is turned into a multiline SMTP response, but for logging, only the
3278 There's a table of default permanent failure response codes to use in
3279 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3280 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3281 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3282 state, because there are broken clients that try VRFY before RCPT. A 5xx
3283 response should be given only when the address is positively known to be
3284 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3285 no explicit code, but if there is one we let it know best.
3286 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3288 From Exim 4.63, it is possible to override the response code details by
3289 providing a suitable response code string at the start of the message provided
3290 in user_msg. The code's first digit is checked for validity.
3293 where where the ACL was called from
3295 user_msg a message that can be included in an SMTP response
3296 log_msg a message for logging
3298 Returns: 0 in most cases
3299 2 if the failure code was FAIL_DROP, in which case the
3300 SMTP connection should be dropped (this value fits with the
3301 "done" variable in smtp_setup_msg() below)
3305 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3307 BOOL drop = rc == FAIL_DROP;
3311 uschar *sender_info = US"";
3313 #ifdef WITH_CONTENT_SCAN
3314 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3316 where == ACL_WHERE_PREDATA ? US"DATA" :
3317 where == ACL_WHERE_DATA ? US"after DATA" :
3318 #ifndef DISABLE_PRDR
3319 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3322 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3323 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3325 if (drop) rc = FAIL;
3327 /* Set the default SMTP code, and allow a user message to change it. */
3329 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3330 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3331 where != ACL_WHERE_VRFY);
3333 /* We used to have sender_address here; however, there was a bug that was not
3334 updating sender_address after a rewrite during a verify. When this bug was
3335 fixed, sender_address at this point became the rewritten address. I'm not sure
3336 this is what should be logged, so I've changed to logging the unrewritten
3337 address to retain backward compatibility. */
3339 #ifndef WITH_CONTENT_SCAN
3340 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3342 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3345 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3346 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3347 sender_host_authenticated ? US" A=" : US"",
3348 sender_host_authenticated ? sender_host_authenticated : US"",
3349 sender_host_authenticated && authenticated_id ? US":" : US"",
3350 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3354 /* If there's been a sender verification failure with a specific message, and
3355 we have not sent a response about it yet, do so now, as a preliminary line for
3356 failures, but not defers. However, always log it for defer, and log it for fail
3357 unless the sender_verify_fail log selector has been turned off. */
3359 if (sender_verified_failed &&
3360 !testflag(sender_verified_failed, af_sverify_told))
3362 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3363 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3365 setflag(sender_verified_failed, af_sverify_told);
3367 if (rc != FAIL || LOGGING(sender_verify_fail))
3368 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3369 host_and_ident(TRUE),
3370 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3371 sender_verified_failed->address,
3372 (sender_verified_failed->message == NULL)? US"" :
3373 string_sprintf(": %s", sender_verified_failed->message));
3375 if (rc == FAIL && sender_verified_failed->user_message)
3376 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3377 testflag(sender_verified_failed, af_verify_pmfail)?
3378 "Postmaster verification failed while checking <%s>\n%s\n"
3379 "Several RFCs state that you are required to have a postmaster\n"
3380 "mailbox for each mail domain. This host does not accept mail\n"
3381 "from domains whose servers reject the postmaster address."
3383 testflag(sender_verified_failed, af_verify_nsfail)?
3384 "Callback setup failed while verifying <%s>\n%s\n"
3385 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3386 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3387 "RFC requirements, and stops you from receiving standard bounce\n"
3388 "messages. This host does not accept mail from domains whose servers\n"
3391 "Verification failed for <%s>\n%s",
3392 sender_verified_failed->address,
3393 sender_verified_failed->user_message));
3395 fl.rcpt_in_progress = save_rcpt_in_progress;
3398 /* Sort out text for logging */
3400 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3401 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3403 /* Send permanent failure response to the command, but the code used isn't
3404 always a 5xx one - see comments at the start of this function. If the original
3405 rc was FAIL_DROP we drop the connection and yield 2. */
3408 smtp_respond(smtp_code, codelen, TRUE,
3409 user_msg ? user_msg : US"Administrative prohibition");
3411 /* Send temporary failure response to the command. Don't give any details,
3412 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3413 verb, and for a header verify when smtp_return_error_details is set.
3415 This conditional logic is all somewhat of a mess because of the odd
3416 interactions between temp_details and return_error_details. One day it should
3417 be re-implemented in a tidier fashion. */
3420 if (f.acl_temp_details && user_msg)
3422 if ( smtp_return_error_details
3423 && sender_verified_failed
3424 && sender_verified_failed->message
3426 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3428 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3431 smtp_respond(smtp_code, codelen, TRUE,
3432 US"Temporary local problem - please try later");
3434 /* Log the incident to the logs that are specified by log_reject_target
3435 (default main, reject). This can be empty to suppress logging of rejections. If
3436 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3437 is closing if required and return 2. */
3439 if (log_reject_target != 0)
3442 gstring * g = s_tlslog(NULL);
3443 uschar * tls = string_from_gstring(g);
3444 if (!tls) tls = US"";
3446 uschar * tls = US"";
3448 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3449 log_reject_target, "%s%s%s %s%srejected %s%s",
3450 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3451 host_and_ident(TRUE),
3454 rc == FAIL ? US"" : US"temporarily ",
3458 if (!drop) return 0;
3460 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3461 smtp_get_connection_info());
3463 /* Run the not-quit ACL, but without any custom messages. This should not be a
3464 problem, because we get here only if some other ACL has issued "drop", and
3465 in that case, *its* custom messages will have been used above. */
3467 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3474 /*************************************************
3475 * Handle SMTP exit when QUIT is not given *
3476 *************************************************/
3478 /* This function provides a logging/statistics hook for when an SMTP connection
3479 is dropped on the floor or the other end goes away. It's a global function
3480 because it's called from receive.c as well as this module. As well as running
3481 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3482 response, either with a custom message from the ACL, or using a default. There
3483 is one case, however, when no message is output - after "drop". In that case,
3484 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3485 passed to this function.
3487 In case things go wrong while processing this function, causing an error that
3488 may re-enter this function, there is a recursion check.
3491 reason What $smtp_notquit_reason will be set to in the ACL;
3492 if NULL, the ACL is not run
3493 code The error code to return as part of the response
3494 defaultrespond The default message if there's no user_msg
3500 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3503 uschar *user_msg = NULL;
3504 uschar *log_msg = NULL;
3506 /* Check for recursive call */
3508 if (fl.smtp_exit_function_called)
3510 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3514 fl.smtp_exit_function_called = TRUE;
3516 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3518 if (acl_smtp_notquit && reason)
3520 smtp_notquit_reason = reason;
3521 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3522 &log_msg)) == ERROR)
3523 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3527 /* If the connection was dropped, we certainly are no longer talking TLS */
3528 tls_in.active.sock = -1;
3530 /* Write an SMTP response if we are expected to give one. As the default
3531 responses are all internal, they should be reasonable size. */
3533 if (code && defaultrespond)
3536 smtp_respond(code, 3, TRUE, user_msg);
3542 va_start(ap, defaultrespond);
3543 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3545 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3554 /*************************************************
3555 * Verify HELO argument *
3556 *************************************************/
3558 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3559 matched. It is also called from ACL processing if verify = helo is used and
3560 verification was not previously tried (i.e. helo_try_verify_hosts was not
3561 matched). The result of its processing is to set helo_verified and
3562 helo_verify_failed. These variables should both be FALSE for this function to
3565 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3566 for IPv6 ::ffff: literals.
3569 Returns: TRUE if testing was completed;
3570 FALSE on a temporary failure
3574 smtp_verify_helo(void)
3578 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3581 if (sender_helo_name == NULL)
3583 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3586 /* Deal with the case of -bs without an IP address */
3588 else if (sender_host_address == NULL)
3590 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3591 f.helo_verified = TRUE;
3594 /* Deal with the more common case when there is a sending IP address */
3596 else if (sender_helo_name[0] == '[')
3598 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3599 Ustrlen(sender_host_address)) == 0;
3602 if (!f.helo_verified)
3604 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3605 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3606 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3611 { if (f.helo_verified) debug_printf("matched host address\n"); }
3614 /* Do a reverse lookup if one hasn't already given a positive or negative
3615 response. If that fails, or the name doesn't match, try checking with a forward
3620 if (sender_host_name == NULL && !host_lookup_failed)
3621 yield = host_name_lookup() != DEFER;
3623 /* If a host name is known, check it and all its aliases. */
3625 if (sender_host_name)
3626 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3628 sender_helo_dnssec = sender_host_dnssec;
3629 HDEBUG(D_receive) debug_printf("matched host name\n");
3633 uschar **aliases = sender_host_aliases;
3635 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3637 sender_helo_dnssec = sender_host_dnssec;
3641 HDEBUG(D_receive) if (f.helo_verified)
3642 debug_printf("matched alias %s\n", *(--aliases));
3645 /* Final attempt: try a forward lookup of the helo name */
3647 if (!f.helo_verified)
3651 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3653 {.request = US"*", .require = US""};
3655 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3657 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3658 NULL, NULL, NULL, &d, NULL, NULL);
3659 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3660 for (host_item * hh = &h; hh; hh = hh->next)
3661 if (Ustrcmp(hh->address, sender_host_address) == 0)
3663 f.helo_verified = TRUE;
3664 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3666 debug_printf("IP address for %s matches calling address\n"
3667 "Forward DNS security status: %sverified\n",
3668 sender_helo_name, sender_helo_dnssec ? "" : "un");
3674 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3681 /*************************************************
3682 * Send user response message *
3683 *************************************************/
3685 /* This function is passed a default response code and a user message. It calls
3686 smtp_message_code() to check and possibly modify the response code, and then
3687 calls smtp_respond() to transmit the response. I put this into a function
3688 just to avoid a lot of repetition.
3691 code the response code
3692 user_msg the user message
3698 smtp_user_msg(uschar *code, uschar *user_msg)
3701 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3702 smtp_respond(code, len, TRUE, user_msg);
3708 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3710 const uschar *set_id = NULL;
3713 /* Run the checking code, passing the remainder of the command line as
3714 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3715 it as the only set numerical variable. The authenticator may set $auth<n>
3716 and also set other numeric variables. The $auth<n> variables are preferred
3717 nowadays; the numerical variables remain for backwards compatibility.
3719 Afterwards, have a go at expanding the set_id string, even if
3720 authentication failed - for bad passwords it can be useful to log the
3721 userid. On success, require set_id to expand and exist, and put it in
3722 authenticated_id. Save this in permanent store, as the working store gets
3723 reset at HELO, RSET, etc. */
3725 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3727 expand_nlength[0] = 0; /* $0 contains nothing */
3729 rc = (au->info->servercode)(au, smtp_cmd_data);
3730 if (au->set_id) set_id = expand_string(au->set_id);
3731 expand_nmax = -1; /* Reset numeric variables */
3732 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3734 /* The value of authenticated_id is stored in the spool file and printed in
3735 log lines. It must not contain binary zeros or newline characters. In
3736 normal use, it never will, but when playing around or testing, this error
3737 can (did) happen. To guard against this, ensure that the id contains only
3738 printing characters. */
3740 if (set_id) set_id = string_printing(set_id);
3742 /* For the non-OK cases, set up additional logging data if set_id
3746 set_id = set_id && *set_id
3747 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3749 /* Switch on the result */
3754 if (!au->set_id || set_id) /* Complete success */
3756 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3757 sender_host_authenticated = au->name;
3758 sender_host_auth_pubname = au->public_name;
3759 authentication_failed = FALSE;
3760 authenticated_fail_id = NULL; /* Impossible to already be set? */
3763 (sender_host_address ? protocols : protocols_local)
3764 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3765 *s = *ss = US"235 Authentication succeeded";
3766 authenticated_by = au;
3770 /* Authentication succeeded, but we failed to expand the set_id string.
3771 Treat this as a temporary error. */
3773 auth_defer_msg = expand_string_message;
3777 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3778 *s = string_sprintf("435 Unable to authenticate at present%s",
3779 auth_defer_user_msg);
3780 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3781 set_id, auth_defer_msg);
3785 *s = *ss = US"501 Invalid base64 data";
3789 *s = *ss = US"501 Authentication cancelled";
3793 *s = *ss = US"553 Initial data not expected";
3797 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3798 *s = US"535 Incorrect authentication data";
3799 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3803 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3804 *s = US"435 Internal error";
3805 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3806 "check", set_id, rc);
3818 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3821 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3823 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3825 rd = Ustrlen(recipient) + 1;
3826 *recipient = rewrite_address_qualify(*recipient, TRUE);
3829 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3831 log_write(L_smtp_syntax_error,
3832 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3833 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3841 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3844 incomplete_transaction_log(US"QUIT");
3847 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3849 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3854 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_CORK, US &on, sizeof(on));
3858 smtp_respond(US"221", 3, TRUE, *user_msgp);
3860 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3863 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3866 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3867 smtp_get_connection_info());
3872 smtp_rset_handler(void)
3875 incomplete_transaction_log(US"RSET");
3876 smtp_printf("250 Reset OK\r\n", FALSE);
3877 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3882 /*************************************************
3883 * Initialize for SMTP incoming message *
3884 *************************************************/
3886 /* This function conducts the initial dialogue at the start of an incoming SMTP
3887 message, and builds a list of recipients. However, if the incoming message
3888 is part of a batch (-bS option) a separate function is called since it would
3889 be messy having tests splattered about all over this function. This function
3890 therefore handles the case where interaction is occurring. The input and output
3891 files are set up in smtp_in and smtp_out.
3893 The global recipients_list is set to point to a vector of recipient_item
3894 blocks, whose number is given by recipients_count. This is extended by the
3895 receive_add_recipient() function. The global variable sender_address is set to
3896 the sender's address. The yield is +1 if a message has been successfully
3897 started, 0 if a QUIT command was encountered or the connection was refused from
3898 the particular host, or -1 if the connection was lost.
3902 Returns: > 0 message successfully started (reached DATA)
3903 = 0 QUIT read or end of file reached or call refused
3908 smtp_setup_msg(void)
3911 BOOL toomany = FALSE;
3912 BOOL discarded = FALSE;
3913 BOOL last_was_rej_mail = FALSE;
3914 BOOL last_was_rcpt = FALSE;
3915 rmark reset_point = store_mark();
3917 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3919 /* Reset for start of new message. We allow one RSET not to be counted as a
3920 nonmail command, for those MTAs that insist on sending it between every
3921 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3922 TLS between messages (an Exim client may do this if it has messages queued up
3923 for the host). Note: we do NOT reset AUTH at this point. */
3925 reset_point = smtp_reset(reset_point);
3926 message_ended = END_NOTSTARTED;
3928 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3930 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3931 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3932 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3934 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3937 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3939 had_command_sigterm = 0;
3940 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3942 /* Batched SMTP is handled in a different function. */
3944 if (smtp_batched_input) return smtp_setup_batch_msg();
3946 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3947 value. The values are 2 larger than the required yield of the function. */
3951 const uschar **argv;
3952 uschar *etrn_command;
3953 uschar *etrn_serialize_key;
3955 uschar *log_msg, *smtp_code;
3956 uschar *user_msg = NULL;
3957 uschar *recipient = NULL;
3958 uschar *hello = NULL;
3960 BOOL was_rej_mail = FALSE;
3961 BOOL was_rcpt = FALSE;
3962 void (*oldsignal)(int);
3964 int start, end, sender_domain, recipient_domain;
3967 uschar *orcpt = NULL;
3972 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3973 if ( tls_in.active.sock >= 0
3975 && tls_in.certificate_verified
3976 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3979 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3981 for (auth_instance * au = auths; au; au = au->next)
3982 if (strcmpic(US"tls", au->driver_name) == 0)
3985 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3986 &user_msg, &log_msg)) != OK
3988 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3991 smtp_cmd_data = NULL;
3993 if (smtp_in_auth(au, &s, &ss) == OK)
3994 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3996 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
4004 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
4005 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4006 US &off, sizeof(off));
4009 switch(smtp_read_command(
4010 #ifndef DISABLE_PIPE_CONNECT
4011 !fl.pipe_connect_acceptable,
4015 GETC_BUFFER_UNLIMITED))
4017 /* The AUTH command is not permitted to occur inside a transaction, and may
4018 occur successfully only once per connection. Actually, that isn't quite
4019 true. When TLS is started, all previous information about a connection must
4020 be discarded, so a new AUTH is permitted at that time.
4022 AUTH may only be used when it has been advertised. However, it seems that
4023 there are clients that send AUTH when it hasn't been advertised, some of
4024 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4025 So there's a get-out that allows this to happen.
4027 AUTH is initially labelled as a "nonmail command" so that one occurrence
4028 doesn't get counted. We change the label here so that multiple failing
4029 AUTHS will eventually hit the nonmail threshold. */
4033 authentication_failed = TRUE;
4034 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4036 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4038 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4039 US"AUTH command used when not advertised");
4042 if (sender_host_authenticated)
4044 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4045 US"already authenticated");
4050 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4051 US"not permitted in mail transaction");
4058 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4059 &user_msg, &log_msg)) != OK
4062 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4066 /* Find the name of the requested authentication mechanism. */
4069 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
4071 if (!isalnum(c) && c != '-' && c != '_')
4073 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4074 US"invalid character in authentication mechanism name");
4080 /* If not at the end of the line, we must be at white space. Terminate the
4081 name and move the pointer on to any data that may be present. */
4083 if (*smtp_cmd_data != 0)
4085 *smtp_cmd_data++ = 0;
4086 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4089 /* Search for an authentication mechanism which is configured for use
4090 as a server and which has been advertised (unless, sigh, allow_auth_
4091 unadvertised is set). */
4095 for (au = auths; au; au = au->next)
4096 if (strcmpic(s, au->public_name) == 0 && au->server &&
4097 (au->advertised || f.allow_auth_unadvertised))
4102 c = smtp_in_auth(au, &s, &ss);
4104 smtp_printf("%s\r\n", FALSE, s);
4106 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4107 au->name, host_and_ident(FALSE), ss);
4110 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4111 string_sprintf("%s authentication mechanism not supported", s));
4114 break; /* AUTH_CMD */
4116 /* The HELO/EHLO commands are permitted to appear in the middle of a
4117 session as well as at the beginning. They have the effect of a reset in
4118 addition to their other functions. Their absence at the start cannot be
4119 taken to be an error.
4123 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4124 or 502 failure replies MUST be returned as appropriate. The SMTP
4125 server MUST stay in the same state after transmitting these replies
4126 that it was in before the EHLO was received.
4128 Therefore, we do not do the reset until after checking the command for
4129 acceptability. This change was made for Exim release 4.11. Previously
4130 it did the reset first. */
4143 HELO_EHLO: /* Common code for HELO and EHLO */
4144 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4145 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4147 /* Reject the HELO if its argument was invalid or non-existent. A
4148 successful check causes the argument to be saved in malloc store. */
4150 if (!check_helo(smtp_cmd_data))
4152 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4154 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4155 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4156 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4157 string_printing(smtp_cmd_argument));
4159 if (++synprot_error_count > smtp_max_synprot_errors)
4161 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4162 "syntax or protocol errors (last command was \"%s\")",
4163 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
4170 /* If sender_host_unknown is true, we have got here via the -bs interface,
4171 not called from inetd. Otherwise, we are running an IP connection and the
4172 host address will be set. If the helo name is the primary name of this
4173 host and we haven't done a reverse lookup, force one now. If helo_required
4174 is set, ensure that the HELO name matches the actual host. If helo_verify
4175 is set, do the same check, but softly. */
4177 if (!f.sender_host_unknown)
4179 BOOL old_helo_verified = f.helo_verified;
4180 uschar *p = smtp_cmd_data;
4182 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4185 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4186 because otherwise the log can be confusing. */
4188 if ( !sender_host_name
4189 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4190 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4191 (void)host_name_lookup();
4193 /* Rebuild the fullhost info to include the HELO name (and the real name
4194 if it was looked up.) */
4196 host_build_sender_fullhost(); /* Rebuild */
4197 set_process_info("handling%s incoming connection from %s",
4198 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4200 /* Verify if configured. This doesn't give much security, but it does
4201 make some people happy to be able to do it. If helo_required is set,
4202 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4203 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4204 now obsolescent, since the verification can now be requested selectively
4207 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4208 if (fl.helo_required || fl.helo_verify)
4210 BOOL tempfail = !smtp_verify_helo();
4211 if (!f.helo_verified)
4213 if (fl.helo_required)
4215 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4216 tempfail? 451 : 550, hello);
4217 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4218 tempfail? "temporarily " : "",
4219 hello, sender_helo_name, host_and_ident(FALSE));
4220 f.helo_verified = old_helo_verified;
4221 break; /* End of HELO/EHLO processing */
4223 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4224 "helo_try_verify_hosts\n", hello);
4230 /* set up SPF context */
4231 spf_conn_init(sender_helo_name, sender_host_address);
4234 /* Apply an ACL check if one is defined; afterwards, recheck
4235 synchronization in case the client started sending in a delay. */
4238 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4239 &user_msg, &log_msg)) != OK)
4241 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4242 sender_helo_name = NULL;
4243 host_build_sender_fullhost(); /* Rebuild */
4246 #ifndef DISABLE_PIPE_CONNECT
4247 else if (!fl.pipe_connect_acceptable && !check_sync())
4249 else if (!check_sync())
4253 /* Generate an OK reply. The default string includes the ident if present,
4254 and also the IP address if present. Reflecting back the ident is intended
4255 as a deterrent to mail forgers. For maximum efficiency, and also because
4256 some broken systems expect each response to be in a single packet, arrange
4257 that the entire reply is sent in one write(). */
4259 fl.auth_advertised = FALSE;
4260 f.smtp_in_pipelining_advertised = FALSE;
4262 fl.tls_advertised = FALSE;
4264 fl.dsn_advertised = FALSE;
4266 fl.smtputf8_advertised = FALSE;
4269 smtp_code = US"250 "; /* Default response code plus space*/
4272 /* sender_host_name below will be tainted, so save on copy when we hit it */
4273 g = string_get_tainted(24, TRUE);
4274 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4276 smtp_active_hostname,
4277 sender_ident ? sender_ident : US"",
4278 sender_ident ? US" at " : US"",
4279 sender_host_name ? sender_host_name : sender_helo_name);
4281 if (sender_host_address)
4282 g = string_fmt_append(g, " [%s]", sender_host_address);
4285 /* A user-supplied EHLO greeting may not contain more than one line. Note
4286 that the code returned by smtp_message_code() includes the terminating
4287 whitespace character. */
4293 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4294 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4295 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4297 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4298 "newlines: message truncated: %s", string_printing(s));
4301 g = string_cat(NULL, s);
4304 g = string_catn(g, US"\r\n", 2);
4306 /* If we received EHLO, we must create a multiline response which includes
4307 the functions supported. */
4313 /* I'm not entirely happy with this, as an MTA is supposed to check
4314 that it has enough room to accept a message of maximum size before
4315 it sends this. However, there seems little point in not sending it.
4316 The actual size check happens later at MAIL FROM time. By postponing it
4317 till then, VRFY and EXPN can be used after EHLO when space is short. */
4319 if (thismessage_size_limit > 0)
4320 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4321 thismessage_size_limit);
4324 g = string_catn(g, smtp_code, 3);
4325 g = string_catn(g, US"-SIZE\r\n", 7);
4328 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4329 clean; if it has an 8-bit character in its hand, it just sends it. It
4330 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4331 However, some users want this option simply in order to stop MUAs
4332 mangling messages that contain top-bit-set characters. It is therefore
4333 provided as an option. */
4335 if (accept_8bitmime)
4337 g = string_catn(g, smtp_code, 3);
4338 g = string_catn(g, US"-8BITMIME\r\n", 11);
4341 /* Advertise DSN support if configured to do so. */
4342 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4344 g = string_catn(g, smtp_code, 3);
4345 g = string_catn(g, US"-DSN\r\n", 6);
4346 fl.dsn_advertised = TRUE;
4349 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4350 permitted to issue them; a check is made when any host actually tries. */
4354 g = string_catn(g, smtp_code, 3);
4355 g = string_catn(g, US"-ETRN\r\n", 7);
4359 g = string_catn(g, smtp_code, 3);
4360 g = string_catn(g, US"-VRFY\r\n", 7);
4364 g = string_catn(g, smtp_code, 3);
4365 g = string_catn(g, US"-EXPN\r\n", 7);
4368 /* Exim is quite happy with pipelining, so let the other end know that
4369 it is safe to use it, unless advertising is disabled. */
4371 if ( f.pipelining_enable
4372 && verify_check_host(&pipelining_advertise_hosts) == OK)
4374 g = string_catn(g, smtp_code, 3);
4375 g = string_catn(g, US"-PIPELINING\r\n", 13);
4376 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4377 f.smtp_in_pipelining_advertised = TRUE;
4379 #ifndef DISABLE_PIPE_CONNECT
4380 if (fl.pipe_connect_acceptable)
4382 f.smtp_in_early_pipe_advertised = TRUE;
4383 g = string_catn(g, smtp_code, 3);
4384 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4390 /* If any server authentication mechanisms are configured, advertise
4391 them if the current host is in auth_advertise_hosts. The problem with
4392 advertising always is that some clients then require users to
4393 authenticate (and aren't configurable otherwise) even though it may not
4394 be necessary (e.g. if the host is in host_accept_relay).
4396 RFC 2222 states that SASL mechanism names contain only upper case
4397 letters, so output the names in upper case, though we actually recognize
4398 them in either case in the AUTH command. */
4402 && !sender_host_authenticated
4404 && verify_check_host(&auth_advertise_hosts) == OK
4408 for (auth_instance * au = auths; au; au = au->next)
4410 au->advertised = FALSE;
4413 DEBUG(D_auth+D_expand) debug_printf_indent(
4414 "Evaluating advertise_condition for %s %s athenticator\n",
4415 au->name, au->public_name);
4416 if ( !au->advertise_condition
4417 || expand_check_condition(au->advertise_condition, au->name,
4424 g = string_catn(g, smtp_code, 3);
4425 g = string_catn(g, US"-AUTH", 5);
4427 fl.auth_advertised = TRUE;
4430 g = string_catn(g, US" ", 1);
4431 g = string_cat (g, au->public_name);
4432 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4433 au->advertised = TRUE;
4438 if (!first) g = string_catn(g, US"\r\n", 2);
4441 /* RFC 3030 CHUNKING */
4443 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4445 g = string_catn(g, smtp_code, 3);
4446 g = string_catn(g, US"-CHUNKING\r\n", 11);
4447 f.chunking_offered = TRUE;
4448 chunking_state = CHUNKING_OFFERED;
4451 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4452 if it has been included in the binary, and the host matches
4453 tls_advertise_hosts. We must *not* advertise if we are already in a
4454 secure connection. */
4457 if (tls_in.active.sock < 0 &&
4458 verify_check_host(&tls_advertise_hosts) != FAIL)
4460 g = string_catn(g, smtp_code, 3);
4461 g = string_catn(g, US"-STARTTLS\r\n", 11);
4462 fl.tls_advertised = TRUE;
4466 #ifndef DISABLE_PRDR
4467 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4470 g = string_catn(g, smtp_code, 3);
4471 g = string_catn(g, US"-PRDR\r\n", 7);
4476 if ( accept_8bitmime
4477 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4479 g = string_catn(g, smtp_code, 3);
4480 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4481 fl.smtputf8_advertised = TRUE;
4485 /* Finish off the multiline reply with one that is always available. */
4487 g = string_catn(g, smtp_code, 3);
4488 g = string_catn(g, US" HELP\r\n", 7);
4491 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4495 if (tls_in.active.sock >= 0)
4496 (void)tls_write(NULL, g->s, g->ptr,
4497 # ifndef DISABLE_PIPE_CONNECT
4498 fl.pipe_connect_acceptable && pipeline_connect_sends());
4506 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4512 (void) string_from_gstring(g);
4513 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4514 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4515 debug_printf("SMTP>> %s", g->s);
4517 fl.helo_seen = TRUE;
4519 /* Reset the protocol and the state, abandoning any previous message. */
4521 (sender_host_address ? protocols : protocols_local)
4523 ? pextend + (sender_host_authenticated ? pauthed : 0)
4525 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4527 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4528 reset_point = smtp_reset(reset_point);
4530 break; /* HELO/EHLO */
4533 /* The MAIL command requires an address as an operand. All we do
4534 here is to parse it for syntactic correctness. The form "<>" is
4535 a special case which converts into an empty string. The start/end
4536 pointers in the original are not used further for this address, as
4537 it is the canonical extracted address which is all that is kept. */
4541 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4542 was_rej_mail = TRUE; /* Reset if accepted */
4543 env_mail_type_t * mail_args; /* Sanity check & validate args */
4545 if (fl.helo_required && !fl.helo_seen)
4547 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4548 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4549 "HELO/EHLO given", host_and_ident(FALSE));
4555 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4556 US"sender already given");
4560 if (!*smtp_cmd_data)
4562 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4563 US"MAIL must have an address operand");
4567 /* Check to see if the limit for messages per connection would be
4568 exceeded by accepting further messages. */
4570 if (smtp_accept_max_per_connection > 0 &&
4571 smtp_mailcmd_count > smtp_accept_max_per_connection)
4573 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4574 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4575 "messages in one connection", host_and_ident(TRUE));
4579 /* Reset for start of message - even if this is going to fail, we
4580 obviously need to throw away any previous data. */
4582 cancel_cutthrough_connection(TRUE, US"MAIL received");
4583 reset_point = smtp_reset(reset_point);
4585 sender_data = recipient_data = NULL;
4587 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4589 if (fl.esmtp) for(;;)
4591 uschar *name, *value, *end;
4592 unsigned long int size;
4593 BOOL arg_error = FALSE;
4595 if (!extract_option(&name, &value)) break;
4597 for (mail_args = env_mail_type_list;
4598 mail_args->value != ENV_MAIL_OPT_NULL;
4601 if (strcmpic(name, mail_args->name) == 0)
4603 if (mail_args->need_value && strcmpic(value, US"") == 0)
4606 switch(mail_args->value)
4608 /* Handle SIZE= by reading the value. We don't do the check till later,
4609 in order to be able to log the sender address on failure. */
4610 case ENV_MAIL_OPT_SIZE:
4611 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4613 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4615 message_size = (int)size;
4621 /* If this session was initiated with EHLO and accept_8bitmime is set,
4622 Exim will have indicated that it supports the BODY=8BITMIME option. In
4623 fact, it does not support this according to the RFCs, in that it does not
4624 take any special action for forwarding messages containing 8-bit
4625 characters. That is why accept_8bitmime is not the default setting, but
4626 some sites want the action that is provided. We recognize both "8BITMIME"
4627 and "7BIT" as body types, but take no action. */
4628 case ENV_MAIL_OPT_BODY:
4629 if (accept_8bitmime) {
4630 if (strcmpic(value, US"8BITMIME") == 0)
4632 else if (strcmpic(value, US"7BIT") == 0)
4637 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4638 US"invalid data for BODY");
4641 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4647 /* Handle the two DSN options, but only if configured to do so (which
4648 will have caused "DSN" to be given in the EHLO response). The code itself
4649 is included only if configured in at build time. */
4651 case ENV_MAIL_OPT_RET:
4652 if (fl.dsn_advertised)
4654 /* Check if RET has already been set */
4657 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4658 US"RET can be specified once only");
4661 dsn_ret = strcmpic(value, US"HDRS") == 0
4663 : strcmpic(value, US"FULL") == 0
4666 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4667 /* Check for invalid invalid value, and exit with error */
4670 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4671 US"Value for RET is invalid");
4676 case ENV_MAIL_OPT_ENVID:
4677 if (fl.dsn_advertised)
4679 /* Check if the dsn envid has been already set */
4682 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4683 US"ENVID can be specified once only");
4686 dsn_envid = string_copy(value);
4687 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4691 /* Handle the AUTH extension. If the value given is not "<>" and either
4692 the ACL says "yes" or there is no ACL but the sending host is
4693 authenticated, we set it up as the authenticated sender. However, if the
4694 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4695 the condition is met. The value of AUTH is an xtext, which means that +,
4696 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4698 case ENV_MAIL_OPT_AUTH:
4699 if (Ustrcmp(value, "<>") != 0)
4704 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4706 /* Put back terminator overrides for error message */
4709 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4710 US"invalid data for AUTH");
4713 if (!acl_smtp_mailauth)
4715 ignore_msg = US"client not authenticated";
4716 rc = sender_host_authenticated ? OK : FAIL;
4720 ignore_msg = US"rejected by ACL";
4721 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4722 &user_msg, &log_msg);
4728 if (authenticated_by == NULL ||
4729 authenticated_by->mail_auth_condition == NULL ||
4730 expand_check_condition(authenticated_by->mail_auth_condition,
4731 authenticated_by->name, US"authenticator"))
4732 break; /* Accept the AUTH */
4734 ignore_msg = US"server_mail_auth_condition failed";
4735 if (authenticated_id != NULL)
4736 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4737 ignore_msg, authenticated_id);
4742 authenticated_sender = NULL;
4743 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4744 value, host_and_ident(TRUE), ignore_msg);
4747 /* Should only get DEFER or ERROR here. Put back terminator
4748 overrides for error message */
4753 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4760 #ifndef DISABLE_PRDR
4761 case ENV_MAIL_OPT_PRDR:
4763 prdr_requested = TRUE;
4768 case ENV_MAIL_OPT_UTF8:
4769 if (!fl.smtputf8_advertised)
4771 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4772 US"SMTPUTF8 used when not advertised");
4776 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4777 message_smtputf8 = allow_utf8_domains = TRUE;
4778 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4780 int old_pool = store_pool;
4781 store_pool = POOL_PERM;
4782 received_protocol = string_sprintf("utf8%s", received_protocol);
4783 store_pool = old_pool;
4788 /* No valid option. Stick back the terminator characters and break
4789 the loop. Do the name-terminator second as extract_option sets
4790 value==name when it found no equal-sign.
4791 An error for a malformed address will occur. */
4792 case ENV_MAIL_OPT_NULL:
4800 /* Break out of for loop if switch() had bad argument or
4801 when start of the email address is reached */
4802 if (arg_error) break;
4805 /* If we have passed the threshold for rate limiting, apply the current
4806 delay, and update it for next time, provided this is a limited host. */
4808 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4809 verify_check_host(&smtp_ratelimit_hosts) == OK)
4811 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4812 smtp_delay_mail/1000.0);
4813 millisleep((int)smtp_delay_mail);
4814 smtp_delay_mail *= smtp_rlm_factor;
4815 if (smtp_delay_mail > (double)smtp_rlm_limit)
4816 smtp_delay_mail = (double)smtp_rlm_limit;
4819 /* Now extract the address, first applying any SMTP-time rewriting. The
4820 TRUE flag allows "<>" as a sender address. */
4822 raw_sender = rewrite_existflags & rewrite_smtp
4823 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4824 global_rewrite_rules)
4828 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4833 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4837 sender_address = raw_sender;
4839 /* If there is a configured size limit for mail, check that this message
4840 doesn't exceed it. The check is postponed to this point so that the sender
4843 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4845 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4846 log_write(L_size_reject,
4847 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4848 "message too big: size%s=%d max=%d",
4850 host_and_ident(TRUE),
4851 (message_size == INT_MAX)? ">" : "",
4853 thismessage_size_limit);
4854 sender_address = NULL;
4858 /* Check there is enough space on the disk unless configured not to.
4859 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4860 plus the current message - i.e. we accept the message only if it won't
4861 reduce the space below the threshold. Add 5000 to the size to allow for
4862 overheads such as the Received: line and storing of recipients, etc.
4863 By putting the check here, even when SIZE is not given, it allow VRFY
4864 and EXPN etc. to be used when space is short. */
4866 if (!receive_check_fs(
4867 smtp_check_spool_space && message_size >= 0
4868 ? message_size + 5000 : 0))
4870 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4871 sender_address = NULL;
4875 /* If sender_address is unqualified, reject it, unless this is a locally
4876 generated message, or the sending host or net is permitted to send
4877 unqualified addresses - typically local machines behaving as MUAs -
4878 in which case just qualify the address. The flag is set above at the start
4879 of the SMTP connection. */
4881 if (!sender_domain && *sender_address)
4882 if (f.allow_unqualified_sender)
4884 sender_domain = Ustrlen(sender_address) + 1;
4885 sender_address = rewrite_address_qualify(sender_address, FALSE);
4886 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4891 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4893 log_write(L_smtp_syntax_error,
4894 LOG_MAIN|LOG_REJECT,
4895 "unqualified sender rejected: <%s> %s%s",
4897 host_and_ident(TRUE),
4899 sender_address = NULL;
4903 /* Apply an ACL check if one is defined, before responding. Afterwards,
4904 when pipelining is not advertised, do another sync check in case the ACL
4905 delayed and the client started sending in the meantime. */
4909 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4910 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4916 if (rc == OK || rc == DISCARD)
4918 BOOL more = pipeline_response();
4921 smtp_printf("%s%s%s", more, US"250 OK",
4922 #ifndef DISABLE_PRDR
4923 prdr_requested ? US", PRDR Requested" : US"",
4930 #ifndef DISABLE_PRDR
4932 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4934 smtp_user_msg(US"250", user_msg);
4936 smtp_delay_rcpt = smtp_rlr_base;
4937 f.recipients_discarded = (rc == DISCARD);
4938 was_rej_mail = FALSE;
4942 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4943 sender_address = NULL;
4948 /* The RCPT command requires an address as an operand. There may be any
4949 number of RCPT commands, specifying multiple recipients. We build them all
4950 into a data structure. The start/end values given by parse_extract_address
4951 are not used, as we keep only the extracted address. */
4956 was_rcpt = fl.rcpt_in_progress = TRUE;
4958 /* There must be a sender address; if the sender was rejected and
4959 pipelining was advertised, we assume the client was pipelining, and do not
4960 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4961 get the same treatment. */
4963 if (sender_address == NULL)
4965 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4967 smtp_printf("503 sender not yet given\r\n", FALSE);
4968 was_rej_mail = TRUE;
4972 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4973 US"sender not yet given");
4974 was_rcpt = FALSE; /* Not a valid RCPT */
4980 /* Check for an operand */
4982 if (smtp_cmd_data[0] == 0)
4984 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4985 US"RCPT must have an address operand");
4990 /* Set the DSN flags orcpt and dsn_flags from the session*/
4994 if (fl.esmtp) for(;;)
4996 uschar *name, *value;
4998 if (!extract_option(&name, &value))
5001 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5003 /* Check whether orcpt has been already set */
5006 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5007 US"ORCPT can be specified once only");
5010 orcpt = string_copy(value);
5011 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5014 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5016 /* Check if the notify flags have been already set */
5019 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5020 US"NOTIFY can be specified once only");
5023 if (strcmpic(value, US"NEVER") == 0)
5024 dsn_flags |= rf_notify_never;
5031 while (*pp != 0 && *pp != ',') pp++;
5032 if (*pp == ',') *pp++ = 0;
5033 if (strcmpic(p, US"SUCCESS") == 0)
5035 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5036 dsn_flags |= rf_notify_success;
5038 else if (strcmpic(p, US"FAILURE") == 0)
5040 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5041 dsn_flags |= rf_notify_failure;
5043 else if (strcmpic(p, US"DELAY") == 0)
5045 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5046 dsn_flags |= rf_notify_delay;
5050 /* Catch any strange values */
5051 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5052 US"Invalid value for NOTIFY parameter");
5057 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5061 /* Unknown option. Stick back the terminator characters and break
5062 the loop. An error for a malformed address will occur. */
5066 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5073 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5074 as a recipient address */
5076 recipient = rewrite_existflags & rewrite_smtp
5077 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5078 global_rewrite_rules)
5081 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5082 &recipient_domain, FALSE)))
5084 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5089 /* If the recipient address is unqualified, reject it, unless this is a
5090 locally generated message. However, unqualified addresses are permitted
5091 from a configured list of hosts and nets - typically when behaving as
5092 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5093 really. The flag is set at the start of the SMTP connection.
5095 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5096 assumed this meant "reserved local part", but the revision of RFC 821 and
5097 friends now makes it absolutely clear that it means *mailbox*. Consequently
5098 we must always qualify this address, regardless. */
5100 if (!recipient_domain)
5101 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5108 /* Check maximum allowed */
5110 if (rcpt_count > recipients_max && recipients_max > 0)
5112 if (recipients_max_reject)
5115 smtp_printf("552 too many recipients\r\n", FALSE);
5117 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5118 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5123 smtp_printf("452 too many recipients\r\n", FALSE);
5125 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5126 "temporarily rejected: sender=<%s> %s", sender_address,
5127 host_and_ident(TRUE));
5134 /* If we have passed the threshold for rate limiting, apply the current
5135 delay, and update it for next time, provided this is a limited host. */
5137 if (rcpt_count > smtp_rlr_threshold &&
5138 verify_check_host(&smtp_ratelimit_hosts) == OK)
5140 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5141 smtp_delay_rcpt/1000.0);
5142 millisleep((int)smtp_delay_rcpt);
5143 smtp_delay_rcpt *= smtp_rlr_factor;
5144 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5145 smtp_delay_rcpt = (double)smtp_rlr_limit;
5148 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5149 for them. Otherwise, check the access control list for this recipient. As
5150 there may be a delay in this, re-check for a synchronization error
5151 afterwards, unless pipelining was advertised. */
5153 if (f.recipients_discarded)
5156 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5158 && !f.smtp_in_pipelining_advertised && !check_sync())
5161 /* The ACL was happy */
5165 BOOL more = pipeline_response();
5168 smtp_user_msg(US"250", user_msg);
5170 smtp_printf("250 Accepted\r\n", more);
5171 receive_add_recipient(recipient, -1);
5173 /* Set the dsn flags in the recipients_list */
5174 recipients_list[recipients_count-1].orcpt = orcpt;
5175 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5177 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5178 recipients_list[recipients_count-1].orcpt,
5179 recipients_list[recipients_count-1].dsn_flags); */
5182 /* The recipient was discarded */
5184 else if (rc == DISCARD)
5187 smtp_user_msg(US"250", user_msg);
5189 smtp_printf("250 Accepted\r\n", FALSE);
5192 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5193 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5194 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5195 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5196 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5199 /* Either the ACL failed the address, or it was deferred. */
5203 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5204 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5209 /* The DATA command is legal only if it follows successful MAIL FROM
5210 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5211 not counted as a protocol error if it follows RCPT (which must have been
5212 rejected if there are no recipients.) This function is complete when a
5213 valid DATA command is encountered.
5215 Note concerning the code used: RFC 2821 says this:
5217 - If there was no MAIL, or no RCPT, command, or all such commands
5218 were rejected, the server MAY return a "command out of sequence"
5219 (503) or "no valid recipients" (554) reply in response to the
5222 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5223 because it is the same whether pipelining is in use or not.
5225 If all the RCPT commands that precede DATA provoked the same error message
5226 (often indicating some kind of system error), it is helpful to include it
5227 with the DATA rejection (an idea suggested by Tony Finch). */
5234 if (chunking_state != CHUNKING_OFFERED)
5236 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5237 US"BDAT command used when CHUNKING not advertised");
5241 /* grab size, endmarker */
5243 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5245 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5246 US"missing size for BDAT command");
5249 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5250 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5251 chunking_data_left = chunking_datasize;
5252 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5253 (int)chunking_state, chunking_data_left);
5255 /* push the current receive_* function on the "stack", and
5256 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5257 functions to do the dirty work. */
5258 lwr_receive_getc = receive_getc;
5259 lwr_receive_getbuf = receive_getbuf;
5260 lwr_receive_ungetc = receive_ungetc;
5262 receive_getc = bdat_getc;
5263 receive_ungetc = bdat_ungetc;
5274 DATA_BDAT: /* Common code for DATA and BDAT */
5275 #ifndef DISABLE_PIPE_CONNECT
5276 fl.pipe_connect_acceptable = FALSE;
5278 if (!discarded && recipients_count <= 0)
5280 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5282 uschar *code = US"503";
5283 int len = Ustrlen(rcpt_smtp_response);
5284 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5286 /* Responses from smtp_printf() will have \r\n on the end */
5287 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5288 rcpt_smtp_response[len-2] = 0;
5289 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5291 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5292 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5293 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5295 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5296 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5297 ? US"valid RCPT command must precede DATA"
5298 : US"valid RCPT command must precede BDAT");
5300 if (chunking_state > CHUNKING_OFFERED)
5305 if (toomany && recipients_max_reject)
5307 sender_address = NULL; /* This will allow a new MAIL without RSET */
5308 sender_address_unrewritten = NULL;
5309 smtp_printf("554 Too many recipients\r\n", FALSE);
5313 if (chunking_state > CHUNKING_OFFERED)
5314 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5317 /* If there is an ACL, re-check the synchronization afterwards, since the
5318 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5319 to get the DATA command sent. */
5321 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5325 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5326 f.enable_dollar_recipients = TRUE;
5327 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5329 f.enable_dollar_recipients = FALSE;
5330 if (rc == OK && !check_sync())
5334 { /* Either the ACL failed the address, or it was deferred. */
5335 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5341 smtp_user_msg(US"354", user_msg);
5344 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5348 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5349 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5350 US &on, sizeof(on));
5353 message_ended = END_NOTENDED; /* Indicate in middle of data */
5364 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5365 &start, &end, &recipient_domain, FALSE)))
5367 smtp_printf("501 %s\r\n", FALSE, errmess);
5371 if (!recipient_domain)
5372 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5376 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5377 &user_msg, &log_msg)) != OK)
5378 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5382 address_item * addr = deliver_make_addr(address, FALSE);
5384 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5385 -1, -1, NULL, NULL, NULL))
5388 s = string_sprintf("250 <%s> is deliverable", address);
5392 s = (addr->user_message != NULL)?
5393 string_sprintf("451 <%s> %s", address, addr->user_message) :
5394 string_sprintf("451 Cannot resolve <%s> at this time", address);
5398 s = (addr->user_message != NULL)?
5399 string_sprintf("550 <%s> %s", address, addr->user_message) :
5400 string_sprintf("550 <%s> is not deliverable", address);
5401 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5402 smtp_cmd_argument, host_and_ident(TRUE));
5406 smtp_printf("%s\r\n", FALSE, s);
5414 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5416 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5419 BOOL save_log_testing_mode = f.log_testing_mode;
5420 f.address_test_mode = f.log_testing_mode = TRUE;
5421 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5422 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5424 f.address_test_mode = FALSE;
5425 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5434 if (!fl.tls_advertised)
5436 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5437 US"STARTTLS command used when not advertised");
5441 /* Apply an ACL check if one is defined */
5443 if ( acl_smtp_starttls
5444 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5445 &user_msg, &log_msg)) != OK
5448 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5452 /* RFC 2487 is not clear on when this command may be sent, though it
5453 does state that all information previously obtained from the client
5454 must be discarded if a TLS session is started. It seems reasonable to
5455 do an implied RSET when STARTTLS is received. */
5457 incomplete_transaction_log(US"STARTTLS");
5458 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5459 reset_point = smtp_reset(reset_point);
5461 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5463 /* There's an attack where more data is read in past the STARTTLS command
5464 before TLS is negotiated, then assumed to be part of the secure session
5465 when used afterwards; we use segregated input buffers, so are not
5466 vulnerable, but we want to note when it happens and, for sheer paranoia,
5467 ensure that the buffer is "wiped".
5468 Pipelining sync checks will normally have protected us too, unless disabled
5469 by configuration. */
5471 if (receive_smtp_buffered())
5474 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5475 if (tls_in.active.sock < 0)
5476 smtp_inend = smtp_inptr = smtp_inbuffer;
5477 /* and if TLS is already active, tls_server_start() should fail */
5480 /* There is nothing we value in the input buffer and if TLS is successfully
5481 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5482 fresh content into it. The buffer contains arbitrary content from an
5483 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5484 It seems safest to just wipe away the content rather than leave it as a
5485 target to jump to. */
5487 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5489 /* Attempt to start up a TLS session, and if successful, discard all
5490 knowledge that was obtained previously. At least, that's what the RFC says,
5491 and that's what happens by default. However, in order to work round YAEB,
5492 there is an option to remember the esmtp state. Sigh.
5494 We must allow for an extra EHLO command and an extra AUTH command after
5495 STARTTLS that don't add to the nonmail command count. */
5498 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5500 if (!tls_remember_esmtp)
5501 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5502 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5503 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5504 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5505 if (sender_helo_name)
5507 sender_helo_name = NULL;
5508 host_build_sender_fullhost(); /* Rebuild */
5509 set_process_info("handling incoming TLS connection from %s",
5510 host_and_ident(FALSE));
5513 (sender_host_address ? protocols : protocols_local)
5515 ? pextend + (sender_host_authenticated ? pauthed : 0)
5517 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5520 sender_host_auth_pubname = sender_host_authenticated = NULL;
5521 authenticated_id = NULL;
5522 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5523 DEBUG(D_tls) debug_printf("TLS active\n");
5524 break; /* Successful STARTTLS */
5527 (void) smtp_log_tls_fail(s);
5529 /* Some local configuration problem was discovered before actually trying
5530 to do a TLS handshake; give a temporary error. */
5534 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5538 /* Hard failure. Reject everything except QUIT or closed connection. One
5539 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5540 set, but we must still reject all incoming commands. Another is a handshake
5541 failure - and there may some encrypted data still in the pipe to us, which we
5542 see as garbage commands. */
5544 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5545 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5548 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5549 smtp_get_connection_info());
5550 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5554 /* It is perhaps arguable as to which exit ACL should be called here,
5555 but as it is probably a situation that almost never arises, it
5556 probably doesn't matter. We choose to call the real QUIT ACL, which in
5557 some sense is perhaps "right". */
5562 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5563 &log_msg)) == ERROR))
5564 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5567 smtp_respond(US"221", 3, TRUE, user_msg);
5569 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5570 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5571 smtp_get_connection_info());
5576 smtp_printf("554 Security failure\r\n", FALSE);
5579 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5584 /* The ACL for QUIT is provided for gathering statistical information or
5585 similar; it does not affect the response code, but it can supply a custom
5589 smtp_quit_handler(&user_msg, &log_msg);
5595 smtp_rset_handler();
5596 cancel_cutthrough_connection(TRUE, US"RSET received");
5597 reset_point = smtp_reset(reset_point);
5604 smtp_printf("250 OK\r\n", FALSE);
5608 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5609 used, a check will be done for permitted hosts. Show STARTTLS only if not
5610 already in a TLS session and if it would be advertised in the EHLO
5615 smtp_printf("214-Commands supported:\r\n", TRUE);
5619 Ustrcat(buffer, US" AUTH");
5621 if (tls_in.active.sock < 0 &&
5622 verify_check_host(&tls_advertise_hosts) != FAIL)
5623 Ustrcat(buffer, US" STARTTLS");
5625 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5626 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5627 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5628 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5629 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5630 smtp_printf("214%s\r\n", FALSE, buffer);
5636 incomplete_transaction_log(US"connection lost");
5637 smtp_notquit_exit(US"connection-lost", US"421",
5638 US"%s lost input connection", smtp_active_hostname);
5640 /* Don't log by default unless in the middle of a message, as some mailers
5641 just drop the call rather than sending QUIT, and it clutters up the logs.
5644 if (sender_address || recipients_count > 0)
5645 log_write(L_lost_incoming_connection, LOG_MAIN,
5646 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5647 f.sender_host_unknown ? "EOF" : "disconnection",
5648 f.tcp_in_fastopen_logged
5651 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5653 host_and_ident(FALSE), smtp_read_error,
5654 string_timesince(&smtp_connection_start)
5658 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5659 smtp_get_connection_info(),
5660 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5662 string_timesince(&smtp_connection_start)
5673 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5674 US"ETRN is not permitted inside a transaction");
5678 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5679 host_and_ident(FALSE));
5681 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5682 &user_msg, &log_msg)) != OK)
5684 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5688 /* Compute the serialization key for this command. */
5690 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5692 /* If a command has been specified for running as a result of ETRN, we
5693 permit any argument to ETRN. If not, only the # standard form is permitted,
5694 since that is strictly the only kind of ETRN that can be implemented
5695 according to the RFC. */
5697 if (smtp_etrn_command)
5701 etrn_command = smtp_etrn_command;
5702 deliver_domain = smtp_cmd_data;
5703 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5704 US"ETRN processing", &error);
5705 deliver_domain = NULL;
5708 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5710 smtp_printf("458 Internal failure\r\n", FALSE);
5715 /* Else set up to call Exim with the -R option. */
5719 if (*smtp_cmd_data++ != '#')
5721 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5722 US"argument must begin with #");
5725 etrn_command = US"exim -R";
5726 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5727 *queue_name ? 4 : 2,
5728 US"-R", smtp_cmd_data,
5729 US"-MCG", queue_name);
5732 /* If we are host-testing, don't actually do anything. */
5738 debug_printf("ETRN command is: %s\n", etrn_command);
5739 debug_printf("ETRN command execution skipped\n");
5741 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5742 else smtp_user_msg(US"250", user_msg);
5747 /* If ETRN queue runs are to be serialized, check the database to
5748 ensure one isn't already running. */
5750 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5752 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5756 /* Fork a child process and run the command. We don't want to have to
5757 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5758 forking. It should be set that way anyway for external incoming SMTP,
5759 but we save and restore to be tidy. If serialization is required, we
5760 actually run the command in yet another process, so we can wait for it
5761 to complete and then remove the serialization lock. */
5763 oldsignal = signal(SIGCHLD, SIG_IGN);
5765 if ((pid = exim_fork(US"etrn-command")) == 0)
5767 smtp_input = FALSE; /* This process is not associated with the */
5768 (void)fclose(smtp_in); /* SMTP call any more. */
5769 (void)fclose(smtp_out);
5771 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5773 /* If not serializing, do the exec right away. Otherwise, fork down
5774 into another process. */
5776 if ( !smtp_etrn_serialize
5777 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5779 DEBUG(D_exec) debug_print_argv(argv);
5780 exim_nullstd(); /* Ensure std{in,out,err} exist */
5781 execv(CS argv[0], (char *const *)argv);
5782 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5783 etrn_command, strerror(errno));
5784 _exit(EXIT_FAILURE); /* paranoia */
5787 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5788 is, we are in the first subprocess, after forking again. All we can do
5789 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5790 complete, before removing the serialization. */
5793 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5794 "failed: %s", strerror(errno));
5798 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5800 (void)wait(&status);
5801 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5805 enq_end(etrn_serialize_key);
5806 exim_underbar_exit(EXIT_SUCCESS);
5809 /* Back in the top level SMTP process. Check that we started a subprocess
5810 and restore the signal state. */
5814 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5816 smtp_printf("458 Unable to fork process\r\n", FALSE);
5817 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5821 smtp_printf("250 OK\r\n", FALSE);
5823 smtp_user_msg(US"250", user_msg);
5825 signal(SIGCHLD, oldsignal);
5830 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5831 US"unexpected argument data");
5835 /* This currently happens only for NULLs, but could be extended. */
5838 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5839 US"NUL character(s) present (shown as '?')");
5840 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5847 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5848 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5849 c = smtp_inend - smtp_inptr;
5850 if (c > 150) c = 150; /* limit logged amount */
5852 incomplete_transaction_log(US"sync failure");
5853 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5854 "(next input sent too soon: pipelining was%s advertised): "
5855 "rejected \"%s\" %s next input=\"%s\"",
5856 f.smtp_in_pipelining_advertised ? "" : " not",
5857 smtp_cmd_buffer, host_and_ident(TRUE),
5858 string_printing(smtp_inptr));
5859 smtp_notquit_exit(US"synchronization-error", US"554",
5860 US"SMTP synchronization error");
5861 done = 1; /* Pretend eof - drops connection */
5865 case TOO_MANY_NONMAIL_CMD:
5866 s = smtp_cmd_buffer;
5867 while (*s != 0 && !isspace(*s)) s++;
5868 incomplete_transaction_log(US"too many non-mail commands");
5869 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5870 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5871 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5872 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5873 done = 1; /* Pretend eof - drops connection */
5876 #ifdef SUPPORT_PROXY
5877 case PROXY_FAIL_IGNORE_CMD:
5878 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5883 if (unknown_command_count++ >= smtp_max_unknown_commands)
5885 log_write(L_smtp_syntax_error, LOG_MAIN,
5886 "SMTP syntax error in \"%s\" %s %s",
5887 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5888 US"unrecognized command");
5889 incomplete_transaction_log(US"unrecognized command");
5890 smtp_notquit_exit(US"bad-commands", US"500",
5891 US"Too many unrecognized commands");
5893 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5894 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5895 string_printing(smtp_cmd_buffer));
5898 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5899 US"unrecognized command");
5903 /* This label is used by goto's inside loops that want to break out to
5904 the end of the command-processing loop. */
5907 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5908 last_was_rcpt = was_rcpt; /* protocol error handling */
5912 return done - 2; /* Convert yield values */
5918 authres_smtpauth(gstring * g)
5920 if (!sender_host_authenticated)
5923 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5925 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5926 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5927 else if (authenticated_id)
5928 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5930 g = string_catn(g, US") reason=x509.auth", 17);
5932 if (authenticated_sender)
5933 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5941 /* End of smtp_in.c */