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"\"");
1822 s_connhad_log(gstring * g)
1824 const uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1825 ? US" C=..." : US" C=";
1827 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++, sep = US",")
1828 if (smtp_connection_had[i] != SCH_NONE)
1829 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1830 for (int i = 0; i < smtp_ch_index; i++, sep = US",")
1831 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1836 /*************************************************
1837 * Log lack of MAIL if so configured *
1838 *************************************************/
1840 /* This function is called when an SMTP session ends. If the log selector
1841 smtp_no_mail is set, write a log line giving some details of what has happened
1842 in the SMTP session.
1849 smtp_log_no_mail(void)
1854 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1857 if (sender_host_authenticated)
1859 g = string_append(g, 2, US" A=", sender_host_authenticated);
1860 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1867 g = s_connhad_log(g);
1869 if (!(s = string_from_gstring(g))) s = US"";
1871 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1872 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1873 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1877 /* Return list of recent smtp commands */
1882 gstring * list = NULL;
1885 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1886 if (smtp_connection_had[i] != SCH_NONE)
1887 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1889 for (int i = 0; i < smtp_ch_index; i++)
1890 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1892 s = string_from_gstring(list);
1893 return s ? s : US"";
1899 /*************************************************
1900 * Check HELO line and set sender_helo_name *
1901 *************************************************/
1903 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1904 the domain name of the sending host, or an ip literal in square brackets. The
1905 argument is placed in sender_helo_name, which is in malloc store, because it
1906 must persist over multiple incoming messages. If helo_accept_junk is set, this
1907 host is permitted to send any old junk (needed for some broken hosts).
1908 Otherwise, helo_allow_chars can be used for rogue characters in general
1909 (typically people want to let in underscores).
1912 s the data portion of the line (already past any white space)
1914 Returns: TRUE or FALSE
1918 check_helo(uschar *s)
1921 uschar *end = s + Ustrlen(s);
1922 BOOL yield = fl.helo_accept_junk;
1924 /* Discard any previous helo name */
1926 sender_helo_name = NULL;
1928 /* Skip tests if junk is permitted. */
1932 /* Allow the new standard form for IPv6 address literals, namely,
1933 [IPv6:....], and because someone is bound to use it, allow an equivalent
1934 IPv4 form. Allow plain addresses as well. */
1941 if (strncmpic(s, US"[IPv6:", 6) == 0)
1942 yield = (string_is_ip_address(s+6, NULL) == 6);
1943 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1944 yield = (string_is_ip_address(s+6, NULL) == 4);
1946 yield = (string_is_ip_address(s+1, NULL) != 0);
1951 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1952 that have been configured (usually underscore - sigh). */
1955 for (yield = TRUE; *s; s++)
1956 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1957 Ustrchr(helo_allow_chars, *s) == NULL)
1963 /* Save argument if OK */
1965 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
1973 /*************************************************
1974 * Extract SMTP command option *
1975 *************************************************/
1977 /* This function picks the next option setting off the end of smtp_cmd_data. It
1978 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1979 things that can appear there.
1982 name point this at the name
1983 value point this at the data string
1985 Returns: TRUE if found an option
1989 extract_option(uschar **name, uschar **value)
1992 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1993 while (isspace(*v)) v--;
1995 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1997 /* Take care to not stop at a space embedded in a quoted local-part */
1999 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
2006 while(isalpha(n[-1])) n--;
2007 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2008 if (!isspace(n[-1])) return FALSE;
2014 if (v == smtp_cmd_data) return FALSE;
2026 /*************************************************
2027 * Reset for new message *
2028 *************************************************/
2030 /* This function is called whenever the SMTP session is reset from
2031 within either of the setup functions; also from the daemon loop.
2033 Argument: the stacking pool storage reset point
2038 smtp_reset(void *reset_point)
2040 recipients_list = NULL;
2041 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2042 raw_recipients_count = recipients_count = recipients_list_max = 0;
2043 message_linecount = 0;
2045 acl_added_headers = NULL;
2046 acl_removed_headers = NULL;
2047 f.queue_only_policy = FALSE;
2048 rcpt_smtp_response = NULL;
2049 fl.rcpt_smtp_response_same = TRUE;
2050 fl.rcpt_in_progress = FALSE;
2051 f.deliver_freeze = FALSE; /* Can be set by ACL */
2052 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2053 fake_response = OK; /* Can be set by ACL */
2054 #ifdef WITH_CONTENT_SCAN
2055 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2057 f.submission_mode = FALSE; /* Can be set by ACL */
2058 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2059 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2060 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2061 sending_ip_address = NULL;
2062 return_path = sender_address = NULL;
2063 deliver_localpart_data = deliver_domain_data =
2064 recipient_data = sender_data = NULL; /* Can be set by ACL */
2065 recipient_verify_failure = NULL;
2066 deliver_localpart_parent = deliver_localpart_orig = NULL;
2067 deliver_domain_parent = deliver_domain_orig = NULL;
2068 callout_address = NULL;
2069 submission_name = NULL; /* Can be set by ACL */
2070 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2071 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2072 sender_verified_list = NULL; /* No senders verified */
2073 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2074 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2076 authenticated_sender = NULL;
2077 #ifdef EXPERIMENTAL_BRIGHTMAIL
2079 bmi_verdicts = NULL;
2081 dnslist_domain = dnslist_matched = NULL;
2083 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2084 spf_result_guessed = FALSE;
2086 #ifndef DISABLE_DKIM
2087 dkim_cur_signer = dkim_signers =
2088 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2089 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2090 f.dkim_disable_verify = FALSE;
2091 dkim_collect_input = 0;
2092 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2093 dkim_key_length = 0;
2095 #ifdef SUPPORT_DMARC
2096 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2097 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2098 dmarc_used_domain = NULL;
2100 #ifdef EXPERIMENTAL_ARC
2101 arc_state = arc_state_reason = NULL;
2102 arc_received_instance = 0;
2106 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2107 #ifndef DISABLE_PRDR
2108 prdr_requested = FALSE;
2111 message_smtputf8 = FALSE;
2113 body_linecount = body_zerocount = 0;
2115 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2116 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2117 /* Note that ratelimiters_conn persists across resets. */
2119 /* Reset message ACL variables */
2123 /* The message body variables use malloc store. They may be set if this is
2124 not the first message in an SMTP session and the previous message caused them
2125 to be referenced in an ACL. */
2129 store_free(message_body);
2130 message_body = NULL;
2133 if (message_body_end)
2135 store_free(message_body_end);
2136 message_body_end = NULL;
2139 /* Warning log messages are also saved in malloc store. They are saved to avoid
2140 repetition in the same message, but it seems right to repeat them for different
2143 while (acl_warn_logged)
2145 string_item *this = acl_warn_logged;
2146 acl_warn_logged = acl_warn_logged->next;
2149 store_reset(reset_point);
2150 return store_mark();
2157 /*************************************************
2158 * Initialize for incoming batched SMTP message *
2159 *************************************************/
2161 /* This function is called from smtp_setup_msg() in the case when
2162 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2163 of messages in one file with SMTP commands between them. All errors must be
2164 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2165 relevant. After an error on a sender, or an invalid recipient, the remainder
2166 of the message is skipped. The value of received_protocol is already set.
2169 Returns: > 0 message successfully started (reached DATA)
2170 = 0 QUIT read or end of file reached
2171 < 0 should not occur
2175 smtp_setup_batch_msg(void)
2178 rmark reset_point = store_mark();
2180 /* Save the line count at the start of each transaction - single commands
2181 like HELO and RSET count as whole transactions. */
2183 bsmtp_transaction_linecount = receive_linecount;
2185 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2187 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2188 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2190 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2191 value. The values are 2 larger than the required yield of the function. */
2196 uschar *recipient = NULL;
2197 int start, end, sender_domain, recipient_domain;
2199 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2201 /* The HELO/EHLO commands set sender_address_helo if they have
2202 valid data; otherwise they are ignored, except that they do
2203 a reset of the state. */
2208 check_helo(smtp_cmd_data);
2212 cancel_cutthrough_connection(TRUE, US"RSET received");
2213 reset_point = smtp_reset(reset_point);
2214 bsmtp_transaction_linecount = receive_linecount;
2218 /* The MAIL FROM command requires an address as an operand. All we
2219 do here is to parse it for syntactic correctness. The form "<>" is
2220 a special case which converts into an empty string. The start/end
2221 pointers in the original are not used further for this address, as
2222 it is the canonical extracted address which is all that is kept. */
2225 smtp_mailcmd_count++; /* Count for no-mail log */
2226 if (sender_address != NULL)
2227 /* The function moan_smtp_batch() does not return. */
2228 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2230 if (smtp_cmd_data[0] == 0)
2231 /* The function moan_smtp_batch() does not return. */
2232 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2234 /* Reset to start of message */
2236 cancel_cutthrough_connection(TRUE, US"MAIL received");
2237 reset_point = smtp_reset(reset_point);
2239 /* Apply SMTP rewrite */
2241 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2242 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2243 US"", global_rewrite_rules) : smtp_cmd_data;
2245 /* Extract the address; the TRUE flag allows <> as valid */
2248 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2252 /* The function moan_smtp_batch() does not return. */
2253 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2255 sender_address = string_copy(raw_sender);
2257 /* Qualify unqualified sender addresses if permitted to do so. */
2260 && sender_address[0] != 0 && sender_address[0] != '@')
2261 if (f.allow_unqualified_sender)
2263 sender_address = rewrite_address_qualify(sender_address, FALSE);
2264 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2265 "and rewritten\n", raw_sender);
2267 /* The function moan_smtp_batch() does not return. */
2269 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2274 /* The RCPT TO command requires an address as an operand. All we do
2275 here is to parse it for syntactic correctness. There may be any number
2276 of RCPT TO commands, specifying multiple senders. We build them all into
2277 a data structure that is in argc/argv format. The start/end values
2278 given by parse_extract_address are not used, as we keep only the
2279 extracted address. */
2282 if (!sender_address)
2283 /* The function moan_smtp_batch() does not return. */
2284 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2286 if (smtp_cmd_data[0] == 0)
2287 /* The function moan_smtp_batch() does not return. */
2288 moan_smtp_batch(smtp_cmd_buffer,
2289 "501 RCPT TO must have an address operand");
2291 /* Check maximum number allowed */
2293 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2294 /* The function moan_smtp_batch() does not return. */
2295 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2296 recipients_max_reject? "552": "452");
2298 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2299 recipient address */
2301 recipient = rewrite_existflags & rewrite_smtp
2302 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2303 global_rewrite_rules)
2306 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2307 &recipient_domain, FALSE);
2310 /* The function moan_smtp_batch() does not return. */
2311 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2313 /* If the recipient address is unqualified, qualify it if permitted. Then
2314 add it to the list of recipients. */
2316 if (!recipient_domain)
2317 if (f.allow_unqualified_recipient)
2319 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2321 recipient = rewrite_address_qualify(recipient, TRUE);
2323 /* The function moan_smtp_batch() does not return. */
2325 moan_smtp_batch(smtp_cmd_buffer,
2326 "501 recipient address must contain a domain");
2328 receive_add_recipient(recipient, -1);
2332 /* The DATA command is legal only if it follows successful MAIL FROM
2333 and RCPT TO commands. This function is complete when a valid DATA
2334 command is encountered. */
2337 if (!sender_address || recipients_count <= 0)
2338 /* The function moan_smtp_batch() does not return. */
2339 if (!sender_address)
2340 moan_smtp_batch(smtp_cmd_buffer,
2341 "503 MAIL FROM:<sender> command must precede DATA");
2343 moan_smtp_batch(smtp_cmd_buffer,
2344 "503 RCPT TO:<recipient> must precede DATA");
2347 done = 3; /* DATA successfully achieved */
2348 message_ended = END_NOTENDED; /* Indicate in middle of message */
2353 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2360 bsmtp_transaction_linecount = receive_linecount;
2371 /* The function moan_smtp_batch() does not return. */
2372 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2377 /* The function moan_smtp_batch() does not return. */
2378 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2383 /* The function moan_smtp_batch() does not return. */
2384 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2389 return done - 2; /* Convert yield values */
2397 smtp_log_tls_fail(uschar * errstr)
2399 uschar * conn_info = smtp_get_connection_info();
2401 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2402 /* I'd like to get separated H= here, but too hard for now */
2404 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2418 socklen_t len = sizeof(is_fastopen);
2420 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2421 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2423 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2428 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2429 f.tcp_in_fastopen = TRUE;
2432 else DEBUG(D_receive)
2433 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2435 # elif defined(TCP_INFO)
2436 struct tcp_info tinfo;
2437 socklen_t len = sizeof(tinfo);
2439 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2440 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2441 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2444 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2445 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2449 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2452 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2453 f.tcp_in_fastopen = TRUE;
2455 else DEBUG(D_receive)
2456 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2462 /*************************************************
2463 * Start an SMTP session *
2464 *************************************************/
2466 /* This function is called at the start of an SMTP session. Thereafter,
2467 smtp_setup_msg() is called to initiate each separate message. This
2468 function does host-specific testing, and outputs the banner line.
2471 Returns: FALSE if the session can not continue; something has
2472 gone wrong, or the connection to the host is blocked
2476 smtp_start_session(void)
2479 uschar *user_msg, *log_msg;
2484 gettimeofday(&smtp_connection_start, NULL);
2485 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2486 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2489 /* Default values for certain variables */
2491 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2492 smtp_mailcmd_count = 0;
2493 count_nonmail = TRUE_UNSET;
2494 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2495 smtp_delay_mail = smtp_rlm_base;
2496 fl.auth_advertised = FALSE;
2497 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2498 f.pipelining_enable = TRUE;
2499 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2500 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2502 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2503 authentication settings from -oMaa to remain in force. */
2505 if (!host_checking && !f.sender_host_notsocket)
2506 sender_host_auth_pubname = sender_host_authenticated = NULL;
2507 authenticated_by = NULL;
2510 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2511 tls_in.ourcert = tls_in.peercert = NULL;
2513 tls_in.ocsp = OCSP_NOT_REQ;
2514 fl.tls_advertised = FALSE;
2516 fl.dsn_advertised = FALSE;
2518 fl.smtputf8_advertised = FALSE;
2521 /* Reset ACL connection variables */
2525 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2527 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, TRUE);
2529 smtp_cmd_buffer[0] = 0;
2530 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2532 /* For batched input, the protocol setting can be overridden from the
2533 command line by a trusted caller. */
2535 if (smtp_batched_input)
2537 if (!received_protocol) received_protocol = US"local-bsmtp";
2540 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2541 reset later if any of EHLO/AUTH/STARTTLS are received. */
2545 (sender_host_address ? protocols : protocols_local) [pnormal];
2547 /* Set up the buffer for inputting using direct read() calls, and arrange to
2548 call the local functions instead of the standard C ones. Place a NUL at the
2549 end of the buffer to safety-stop C-string reads from it. */
2551 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2552 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2553 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2555 receive_getc = smtp_getc;
2556 receive_getbuf = smtp_getbuf;
2557 receive_get_cache = smtp_get_cache;
2558 receive_ungetc = smtp_ungetc;
2559 receive_feof = smtp_feof;
2560 receive_ferror = smtp_ferror;
2561 receive_smtp_buffered = smtp_buffered;
2562 smtp_inptr = smtp_inend = smtp_inbuffer;
2563 smtp_had_eof = smtp_had_error = 0;
2565 /* Set up the message size limit; this may be host-specific */
2567 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2568 if (expand_string_message)
2570 if (thismessage_size_limit == -1)
2571 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2572 "%s", expand_string_message);
2574 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2575 "%s", expand_string_message);
2576 smtp_closedown(US"Temporary local problem - please try later");
2580 /* When a message is input locally via the -bs or -bS options, sender_host_
2581 unknown is set unless -oMa was used to force an IP address, in which case it
2582 is checked like a real remote connection. When -bs is used from inetd, this
2583 flag is not set, causing the sending host to be checked. The code that deals
2584 with IP source routing (if configured) is never required for -bs or -bS and
2585 the flag sender_host_notsocket is used to suppress it.
2587 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2588 reserve for certain hosts and/or networks. */
2590 if (!f.sender_host_unknown)
2593 BOOL reserved_host = FALSE;
2595 /* Look up IP options (source routing info) on the socket if this is not an
2596 -oMa "host", and if any are found, log them and drop the connection.
2598 Linux (and others now, see below) is different to everyone else, so there
2599 has to be some conditional compilation here. Versions of Linux before 2.1.15
2600 used a structure whose name was "options". Somebody finally realized that
2601 this name was silly, and it got changed to "ip_options". I use the
2602 newer name here, but there is a fudge in the script that sets up os.h
2603 to define a macro in older Linux systems.
2605 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2606 glibc 2, which has chosen ip_opts for the structure name. This is now
2607 really a glibc thing rather than a Linux thing, so the condition name
2608 has been changed to reflect this. It is relevant also to GNU/Hurd.
2610 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2611 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2612 a special macro defined in the os.h file.
2614 Some DGUX versions on older hardware appear not to support IP options at
2615 all, so there is now a general macro which can be set to cut out this
2618 How to do this properly in IPv6 is not yet known. */
2620 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2622 #ifdef GLIBC_IP_OPTIONS
2623 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2628 #elif defined DARWIN_IP_OPTIONS
2634 if (!host_checking && !f.sender_host_notsocket)
2637 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2638 struct ip_options *ipopt = store_get(optlen, FALSE);
2640 struct ip_opts ipoptblock;
2641 struct ip_opts *ipopt = &ipoptblock;
2642 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2644 struct ipoption ipoptblock;
2645 struct ipoption *ipopt = &ipoptblock;
2646 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2649 /* Occasional genuine failures of getsockopt() have been seen - for
2650 example, "reset by peer". Therefore, just log and give up on this
2651 call, unless the error is ENOPROTOOPT. This error is given by systems
2652 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2653 of writing. So for that error, carry on - we just can't do an IP options
2656 DEBUG(D_receive) debug_printf("checking for IP options\n");
2658 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2661 if (errno != ENOPROTOOPT)
2663 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2664 host_and_ident(FALSE), strerror(errno));
2665 smtp_printf("451 SMTP service not available\r\n", FALSE);
2670 /* Deal with any IP options that are set. On the systems I have looked at,
2671 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2672 more logging data than will fit in big_buffer. Nevertheless, after somebody
2673 questioned this code, I've added in some paranoid checking. */
2675 else if (optlen > 0)
2677 uschar *p = big_buffer;
2678 uschar *pend = big_buffer + big_buffer_size;
2681 struct in_addr addr;
2684 uschar *optstart = US (ipopt->__data);
2686 uschar *optstart = US (ipopt->ip_opts);
2688 uschar *optstart = US (ipopt->ipopt_list);
2691 DEBUG(D_receive) debug_printf("IP options exist\n");
2693 Ustrcpy(p, "IP options on incoming call:");
2696 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2709 if (!string_format(p, pend-p, " %s [@%s",
2710 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2712 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2714 inet_ntoa(ipopt->ip_dst)))
2716 inet_ntoa(ipopt->ipopt_dst)))
2724 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2726 while (optcount-- > 0)
2728 memcpy(&addr, adptr, sizeof(addr));
2729 if (!string_format(p, pend - p - 1, "%s%s",
2730 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2736 adptr += sizeof(struct in_addr);
2744 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2747 for (int i = 0; i < opt[1]; i++)
2748 p += sprintf(CS p, "%2.2x ", opt[i]);
2756 log_write(0, LOG_MAIN, "%s", big_buffer);
2758 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2760 log_write(0, LOG_MAIN|LOG_REJECT,
2761 "connection from %s refused (IP options)", host_and_ident(FALSE));
2763 smtp_printf("554 SMTP service not available\r\n", FALSE);
2767 /* Length of options = 0 => there are no options */
2769 else DEBUG(D_receive) debug_printf("no IP options found\n");
2771 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2773 /* Set keep-alive in socket options. The option is on by default. This
2774 setting is an attempt to get rid of some hanging connections that stick in
2775 read() when the remote end (usually a dialup) goes away. */
2777 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2778 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2780 /* If the current host matches host_lookup, set the name by doing a
2781 reverse lookup. On failure, sender_host_name will be NULL and
2782 host_lookup_failed will be TRUE. This may or may not be serious - optional
2785 if (verify_check_host(&host_lookup) == OK)
2787 (void)host_name_lookup();
2788 host_build_sender_fullhost();
2791 /* Delay this until we have the full name, if it is looked up. */
2793 set_process_info("handling incoming connection from %s",
2794 host_and_ident(FALSE));
2796 /* Expand smtp_receive_timeout, if needed */
2798 if (smtp_receive_timeout_s)
2801 if ( !(exp = expand_string(smtp_receive_timeout_s))
2803 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2805 log_write(0, LOG_MAIN|LOG_PANIC,
2806 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2809 /* Test for explicit connection rejection */
2811 if (verify_check_host(&host_reject_connection) == OK)
2813 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2814 "from %s (host_reject_connection)", host_and_ident(FALSE));
2815 smtp_printf("554 SMTP service not available\r\n", FALSE);
2819 /* Test with TCP Wrappers if so configured. There is a problem in that
2820 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2821 such as disks dying. In these cases, it is desirable to reject with a 4xx
2822 error instead of a 5xx error. There isn't a "right" way to detect such
2823 problems. The following kludge is used: errno is zeroed before calling
2824 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2825 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2828 #ifdef USE_TCP_WRAPPERS
2830 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2831 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2832 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2833 expand_string_message);
2835 if (!hosts_ctl(tcp_wrappers_name,
2836 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2837 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2838 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2840 if (errno == 0 || errno == ENOENT)
2842 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2843 log_write(L_connection_reject,
2844 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2845 "(tcp wrappers)", host_and_ident(FALSE));
2846 smtp_printf("554 SMTP service not available\r\n", FALSE);
2850 int save_errno = errno;
2851 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2852 "errno value %d\n", save_errno);
2853 log_write(L_connection_reject,
2854 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2855 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2856 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2862 /* Check for reserved slots. The value of smtp_accept_count has already been
2863 incremented to include this process. */
2865 if (smtp_accept_max > 0 &&
2866 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2868 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2870 log_write(L_connection_reject,
2871 LOG_MAIN, "temporarily refused connection from %s: not in "
2872 "reserve list: connected=%d max=%d reserve=%d%s",
2873 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2874 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2875 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2876 "please try again later\r\n", FALSE, smtp_active_hostname);
2879 reserved_host = TRUE;
2882 /* If a load level above which only messages from reserved hosts are
2883 accepted is set, check the load. For incoming calls via the daemon, the
2884 check is done in the superior process if there are no reserved hosts, to
2885 save a fork. In all cases, the load average will already be available
2886 in a global variable at this point. */
2888 if (smtp_load_reserve >= 0 &&
2889 load_average > smtp_load_reserve &&
2891 verify_check_host(&smtp_reserve_hosts) != OK)
2893 log_write(L_connection_reject,
2894 LOG_MAIN, "temporarily refused connection from %s: not in "
2895 "reserve list and load average = %.2f", host_and_ident(FALSE),
2896 (double)load_average/1000.0);
2897 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2898 smtp_active_hostname);
2902 /* Determine whether unqualified senders or recipients are permitted
2903 for this host. Unfortunately, we have to do this every time, in order to
2904 set the flags so that they can be inspected when considering qualifying
2905 addresses in the headers. For a site that permits no qualification, this
2906 won't take long, however. */
2908 f.allow_unqualified_sender =
2909 verify_check_host(&sender_unqualified_hosts) == OK;
2911 f.allow_unqualified_recipient =
2912 verify_check_host(&recipient_unqualified_hosts) == OK;
2914 /* Determine whether HELO/EHLO is required for this host. The requirement
2915 can be hard or soft. */
2917 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2918 if (!fl.helo_required)
2919 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2921 /* Determine whether this hosts is permitted to send syntactic junk
2922 after a HELO or EHLO command. */
2924 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2927 /* For batch SMTP input we are now done. */
2929 if (smtp_batched_input) return TRUE;
2931 /* If valid Proxy Protocol source is connecting, set up session.
2932 * Failure will not allow any SMTP function other than QUIT. */
2934 #ifdef SUPPORT_PROXY
2935 proxy_session = FALSE;
2936 f.proxy_session_failed = FALSE;
2937 if (check_proxy_protocol_host())
2938 setup_proxy_protocol_host();
2941 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2942 smtps port for use with older style SSL MTAs. */
2945 if (tls_in.on_connect)
2947 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2948 return smtp_log_tls_fail(user_msg);
2949 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2953 /* Run the connect ACL if it exists */
2956 if (acl_smtp_connect)
2959 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2962 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2967 /* Output the initial message for a two-way SMTP connection. It may contain
2968 newlines, which then cause a multi-line response to be given. */
2970 code = US"220"; /* Default status code */
2971 esc = US""; /* Default extended status code */
2972 esclen = 0; /* Length of esc */
2976 if (!(s = expand_string(smtp_banner)))
2977 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2978 "failed: %s", smtp_banner, expand_string_message);
2984 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2988 esclen = codelen - 4;
2992 /* Remove any terminating newlines; might as well remove trailing space too */
2995 while (p > s && isspace(p[-1])) p--;
2998 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2999 is all contained in a single IP packet. The original code wrote out the
3000 greeting using several calls to fprint/fputc, and on busy servers this could
3001 cause it to be split over more than one packet - which caused CC:Mail to fall
3002 over when it got the second part of the greeting after sending its first
3003 command. Sigh. To try to avoid this, build the complete greeting message
3004 first, and output it in one fell swoop. This gives a better chance of it
3005 ending up as a single packet. */
3007 ss = string_get(256);
3010 do /* At least once, in case we have an empty string */
3013 uschar *linebreak = Ustrchr(p, '\n');
3014 ss = string_catn(ss, code, 3);
3018 ss = string_catn(ss, US" ", 1);
3022 len = linebreak - p;
3023 ss = string_catn(ss, US"-", 1);
3025 ss = string_catn(ss, esc, esclen);
3026 ss = string_catn(ss, p, len);
3027 ss = string_catn(ss, US"\r\n", 2);
3033 /* Before we write the banner, check that there is no input pending, unless
3034 this synchronisation check is disabled. */
3036 #ifndef DISABLE_PIPE_CONNECT
3037 fl.pipe_connect_acceptable =
3038 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3041 if (fl.pipe_connect_acceptable)
3042 f.smtp_in_early_pipe_used = TRUE;
3048 unsigned n = smtp_inend - smtp_inptr;
3049 if (n > 128) n = 128;
3051 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3052 "synchronization error (input sent without waiting for greeting): "
3053 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3054 string_printing(string_copyn(smtp_inptr, n)));
3055 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3059 /* Now output the banner */
3060 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3063 #ifndef DISABLE_PIPE_CONNECT
3064 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3068 string_from_gstring(ss));
3070 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3071 handshake arrived. If so we must have managed a TFO. */
3074 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3084 /*************************************************
3085 * Handle SMTP syntax and protocol errors *
3086 *************************************************/
3088 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3089 to do so. Then transmit the error response. The return value depends on the
3090 number of syntax and protocol errors in this SMTP session.
3093 type error type, given as a log flag bit
3094 code response code; <= 0 means don't send a response
3095 data data to reflect in the response (can be NULL)
3096 errmess the error message
3098 Returns: -1 limit of syntax/protocol errors NOT exceeded
3099 +1 limit of syntax/protocol errors IS exceeded
3101 These values fit in with the values of the "done" variable in the main
3102 processing loop in smtp_setup_msg(). */
3105 synprot_error(int type, int code, uschar *data, uschar *errmess)
3109 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3110 type == L_smtp_syntax_error ? "syntax" : "protocol",
3111 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3113 if (++synprot_error_count > smtp_max_synprot_errors)
3116 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3117 "syntax or protocol errors (last command was \"%s\", %s)",
3118 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3119 string_from_gstring(s_connhad_log(NULL))
3125 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3126 data ? data : US"", data ? US": " : US"", errmess);
3128 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3137 /*************************************************
3138 * Send SMTP response, possibly multiline *
3139 *************************************************/
3141 /* There are, it seems, broken clients out there that cannot handle multiline
3142 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3143 output nothing for non-final calls, and only the first line for anything else.
3146 code SMTP code, may involve extended status codes
3147 codelen length of smtp code; if > 4 there's an ESC
3148 final FALSE if the last line isn't the final line
3149 msg message text, possibly containing newlines
3155 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3160 if (!final && f.no_multiline_responses) return;
3165 esclen = codelen - 4;
3168 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3169 have had the same. Note: this code is also present in smtp_printf(). It would
3170 be tidier to have it only in one place, but when it was added, it was easier to
3171 do it that way, so as not to have to mess with the code for the RCPT command,
3172 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3174 if (fl.rcpt_in_progress)
3176 if (rcpt_smtp_response == NULL)
3177 rcpt_smtp_response = string_copy(msg);
3178 else if (fl.rcpt_smtp_response_same &&
3179 Ustrcmp(rcpt_smtp_response, msg) != 0)
3180 fl.rcpt_smtp_response_same = FALSE;
3181 fl.rcpt_in_progress = FALSE;
3184 /* Now output the message, splitting it up into multiple lines if necessary.
3185 We only handle pipelining these responses as far as nonfinal/final groups,
3186 not the whole MAIL/RCPT/DATA response set. */
3190 uschar *nl = Ustrchr(msg, '\n');
3193 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3196 else if (nl[1] == 0 || f.no_multiline_responses)
3198 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3199 (int)(nl - msg), msg);
3204 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3206 Uskip_whitespace(&msg);
3214 /*************************************************
3215 * Parse user SMTP message *
3216 *************************************************/
3218 /* This function allows for user messages overriding the response code details
3219 by providing a suitable response code string at the start of the message
3220 user_msg. Check the message for starting with a response code and optionally an
3221 extended status code. If found, check that the first digit is valid, and if so,
3222 change the code pointer and length to use the replacement. An invalid code
3223 causes a panic log; in this case, if the log messages is the same as the user
3224 message, we must also adjust the value of the log message to show the code that
3225 is actually going to be used (the original one).
3227 This function is global because it is called from receive.c as well as within
3230 Note that the code length returned includes the terminating whitespace
3231 character, which is always included in the regex match.
3234 code SMTP code, may involve extended status codes
3235 codelen length of smtp code; if > 4 there's an ESC
3237 log_msg optional log message, to be adjusted with the new SMTP code
3238 check_valid if true, verify the response code
3244 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3250 if (!msg || !*msg) return;
3252 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3253 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3255 if (check_valid && (*msg)[0] != (*code)[0])
3257 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3258 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3259 if (log_msg != NULL && *log_msg == *msg)
3260 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3265 *codelen = ovector[1]; /* Includes final space */
3267 *msg += ovector[1]; /* Chop the code off the message */
3274 /*************************************************
3275 * Handle an ACL failure *
3276 *************************************************/
3278 /* This function is called when acl_check() fails. As well as calls from within
3279 this module, it is called from receive.c for an ACL after DATA. It sorts out
3280 logging the incident, and sends the error response. A message containing
3281 newlines is turned into a multiline SMTP response, but for logging, only the
3284 There's a table of default permanent failure response codes to use in
3285 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3286 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3287 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3288 state, because there are broken clients that try VRFY before RCPT. A 5xx
3289 response should be given only when the address is positively known to be
3290 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3291 no explicit code, but if there is one we let it know best.
3292 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3294 From Exim 4.63, it is possible to override the response code details by
3295 providing a suitable response code string at the start of the message provided
3296 in user_msg. The code's first digit is checked for validity.
3299 where where the ACL was called from
3301 user_msg a message that can be included in an SMTP response
3302 log_msg a message for logging
3304 Returns: 0 in most cases
3305 2 if the failure code was FAIL_DROP, in which case the
3306 SMTP connection should be dropped (this value fits with the
3307 "done" variable in smtp_setup_msg() below)
3311 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3313 BOOL drop = rc == FAIL_DROP;
3317 uschar *sender_info = US"";
3319 #ifdef WITH_CONTENT_SCAN
3320 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3322 where == ACL_WHERE_PREDATA ? US"DATA" :
3323 where == ACL_WHERE_DATA ? US"after DATA" :
3324 #ifndef DISABLE_PRDR
3325 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3328 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3329 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3331 if (drop) rc = FAIL;
3333 /* Set the default SMTP code, and allow a user message to change it. */
3335 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3336 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3337 where != ACL_WHERE_VRFY);
3339 /* We used to have sender_address here; however, there was a bug that was not
3340 updating sender_address after a rewrite during a verify. When this bug was
3341 fixed, sender_address at this point became the rewritten address. I'm not sure
3342 this is what should be logged, so I've changed to logging the unrewritten
3343 address to retain backward compatibility. */
3345 #ifndef WITH_CONTENT_SCAN
3346 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3348 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3351 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3352 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3353 sender_host_authenticated ? US" A=" : US"",
3354 sender_host_authenticated ? sender_host_authenticated : US"",
3355 sender_host_authenticated && authenticated_id ? US":" : US"",
3356 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3360 /* If there's been a sender verification failure with a specific message, and
3361 we have not sent a response about it yet, do so now, as a preliminary line for
3362 failures, but not defers. However, always log it for defer, and log it for fail
3363 unless the sender_verify_fail log selector has been turned off. */
3365 if (sender_verified_failed &&
3366 !testflag(sender_verified_failed, af_sverify_told))
3368 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3369 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3371 setflag(sender_verified_failed, af_sverify_told);
3373 if (rc != FAIL || LOGGING(sender_verify_fail))
3374 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3375 host_and_ident(TRUE),
3376 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3377 sender_verified_failed->address,
3378 (sender_verified_failed->message == NULL)? US"" :
3379 string_sprintf(": %s", sender_verified_failed->message));
3381 if (rc == FAIL && sender_verified_failed->user_message)
3382 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3383 testflag(sender_verified_failed, af_verify_pmfail)?
3384 "Postmaster verification failed while checking <%s>\n%s\n"
3385 "Several RFCs state that you are required to have a postmaster\n"
3386 "mailbox for each mail domain. This host does not accept mail\n"
3387 "from domains whose servers reject the postmaster address."
3389 testflag(sender_verified_failed, af_verify_nsfail)?
3390 "Callback setup failed while verifying <%s>\n%s\n"
3391 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3392 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3393 "RFC requirements, and stops you from receiving standard bounce\n"
3394 "messages. This host does not accept mail from domains whose servers\n"
3397 "Verification failed for <%s>\n%s",
3398 sender_verified_failed->address,
3399 sender_verified_failed->user_message));
3401 fl.rcpt_in_progress = save_rcpt_in_progress;
3404 /* Sort out text for logging */
3406 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3407 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3409 /* Send permanent failure response to the command, but the code used isn't
3410 always a 5xx one - see comments at the start of this function. If the original
3411 rc was FAIL_DROP we drop the connection and yield 2. */
3414 smtp_respond(smtp_code, codelen, TRUE,
3415 user_msg ? user_msg : US"Administrative prohibition");
3417 /* Send temporary failure response to the command. Don't give any details,
3418 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3419 verb, and for a header verify when smtp_return_error_details is set.
3421 This conditional logic is all somewhat of a mess because of the odd
3422 interactions between temp_details and return_error_details. One day it should
3423 be re-implemented in a tidier fashion. */
3426 if (f.acl_temp_details && user_msg)
3428 if ( smtp_return_error_details
3429 && sender_verified_failed
3430 && sender_verified_failed->message
3432 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3434 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3437 smtp_respond(smtp_code, codelen, TRUE,
3438 US"Temporary local problem - please try later");
3440 /* Log the incident to the logs that are specified by log_reject_target
3441 (default main, reject). This can be empty to suppress logging of rejections. If
3442 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3443 is closing if required and return 2. */
3445 if (log_reject_target != 0)
3448 gstring * g = s_tlslog(NULL);
3449 uschar * tls = string_from_gstring(g);
3450 if (!tls) tls = US"";
3452 uschar * tls = US"";
3454 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3455 log_reject_target, "%s%s%s %s%srejected %s%s",
3456 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3457 host_and_ident(TRUE),
3460 rc == FAIL ? US"" : US"temporarily ",
3464 if (!drop) return 0;
3466 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3467 smtp_get_connection_info());
3469 /* Run the not-quit ACL, but without any custom messages. This should not be a
3470 problem, because we get here only if some other ACL has issued "drop", and
3471 in that case, *its* custom messages will have been used above. */
3473 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3480 /*************************************************
3481 * Handle SMTP exit when QUIT is not given *
3482 *************************************************/
3484 /* This function provides a logging/statistics hook for when an SMTP connection
3485 is dropped on the floor or the other end goes away. It's a global function
3486 because it's called from receive.c as well as this module. As well as running
3487 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3488 response, either with a custom message from the ACL, or using a default. There
3489 is one case, however, when no message is output - after "drop". In that case,
3490 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3491 passed to this function.
3493 In case things go wrong while processing this function, causing an error that
3494 may re-enter this function, there is a recursion check.
3497 reason What $smtp_notquit_reason will be set to in the ACL;
3498 if NULL, the ACL is not run
3499 code The error code to return as part of the response
3500 defaultrespond The default message if there's no user_msg
3506 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3509 uschar *user_msg = NULL;
3510 uschar *log_msg = NULL;
3512 /* Check for recursive call */
3514 if (fl.smtp_exit_function_called)
3516 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3520 fl.smtp_exit_function_called = TRUE;
3522 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3524 if (acl_smtp_notquit && reason)
3526 smtp_notquit_reason = reason;
3527 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3528 &log_msg)) == ERROR)
3529 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3533 /* If the connection was dropped, we certainly are no longer talking TLS */
3534 tls_in.active.sock = -1;
3536 /* Write an SMTP response if we are expected to give one. As the default
3537 responses are all internal, they should be reasonable size. */
3539 if (code && defaultrespond)
3542 smtp_respond(code, 3, TRUE, user_msg);
3548 va_start(ap, defaultrespond);
3549 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3551 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3560 /*************************************************
3561 * Verify HELO argument *
3562 *************************************************/
3564 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3565 matched. It is also called from ACL processing if verify = helo is used and
3566 verification was not previously tried (i.e. helo_try_verify_hosts was not
3567 matched). The result of its processing is to set helo_verified and
3568 helo_verify_failed. These variables should both be FALSE for this function to
3571 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3572 for IPv6 ::ffff: literals.
3575 Returns: TRUE if testing was completed;
3576 FALSE on a temporary failure
3580 smtp_verify_helo(void)
3584 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3587 if (sender_helo_name == NULL)
3589 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3592 /* Deal with the case of -bs without an IP address */
3594 else if (sender_host_address == NULL)
3596 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3597 f.helo_verified = TRUE;
3600 /* Deal with the more common case when there is a sending IP address */
3602 else if (sender_helo_name[0] == '[')
3604 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3605 Ustrlen(sender_host_address)) == 0;
3608 if (!f.helo_verified)
3610 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3611 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3612 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3617 { if (f.helo_verified) debug_printf("matched host address\n"); }
3620 /* Do a reverse lookup if one hasn't already given a positive or negative
3621 response. If that fails, or the name doesn't match, try checking with a forward
3626 if (sender_host_name == NULL && !host_lookup_failed)
3627 yield = host_name_lookup() != DEFER;
3629 /* If a host name is known, check it and all its aliases. */
3631 if (sender_host_name)
3632 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3634 sender_helo_dnssec = sender_host_dnssec;
3635 HDEBUG(D_receive) debug_printf("matched host name\n");
3639 uschar **aliases = sender_host_aliases;
3641 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3643 sender_helo_dnssec = sender_host_dnssec;
3647 HDEBUG(D_receive) if (f.helo_verified)
3648 debug_printf("matched alias %s\n", *(--aliases));
3651 /* Final attempt: try a forward lookup of the helo name */
3653 if (!f.helo_verified)
3657 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3659 {.request = US"*", .require = US""};
3661 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3663 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3664 NULL, NULL, NULL, &d, NULL, NULL);
3665 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3666 for (host_item * hh = &h; hh; hh = hh->next)
3667 if (Ustrcmp(hh->address, sender_host_address) == 0)
3669 f.helo_verified = TRUE;
3670 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3672 debug_printf("IP address for %s matches calling address\n"
3673 "Forward DNS security status: %sverified\n",
3674 sender_helo_name, sender_helo_dnssec ? "" : "un");
3680 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3687 /*************************************************
3688 * Send user response message *
3689 *************************************************/
3691 /* This function is passed a default response code and a user message. It calls
3692 smtp_message_code() to check and possibly modify the response code, and then
3693 calls smtp_respond() to transmit the response. I put this into a function
3694 just to avoid a lot of repetition.
3697 code the response code
3698 user_msg the user message
3704 smtp_user_msg(uschar *code, uschar *user_msg)
3707 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3708 smtp_respond(code, len, TRUE, user_msg);
3714 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3716 const uschar *set_id = NULL;
3719 /* Run the checking code, passing the remainder of the command line as
3720 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3721 it as the only set numerical variable. The authenticator may set $auth<n>
3722 and also set other numeric variables. The $auth<n> variables are preferred
3723 nowadays; the numerical variables remain for backwards compatibility.
3725 Afterwards, have a go at expanding the set_id string, even if
3726 authentication failed - for bad passwords it can be useful to log the
3727 userid. On success, require set_id to expand and exist, and put it in
3728 authenticated_id. Save this in permanent store, as the working store gets
3729 reset at HELO, RSET, etc. */
3731 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3733 expand_nlength[0] = 0; /* $0 contains nothing */
3735 rc = (au->info->servercode)(au, smtp_cmd_data);
3736 if (au->set_id) set_id = expand_string(au->set_id);
3737 expand_nmax = -1; /* Reset numeric variables */
3738 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3740 /* The value of authenticated_id is stored in the spool file and printed in
3741 log lines. It must not contain binary zeros or newline characters. In
3742 normal use, it never will, but when playing around or testing, this error
3743 can (did) happen. To guard against this, ensure that the id contains only
3744 printing characters. */
3746 if (set_id) set_id = string_printing(set_id);
3748 /* For the non-OK cases, set up additional logging data if set_id
3752 set_id = set_id && *set_id
3753 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3755 /* Switch on the result */
3760 if (!au->set_id || set_id) /* Complete success */
3762 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3763 sender_host_authenticated = au->name;
3764 sender_host_auth_pubname = au->public_name;
3765 authentication_failed = FALSE;
3766 authenticated_fail_id = NULL; /* Impossible to already be set? */
3769 (sender_host_address ? protocols : protocols_local)
3770 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3771 *s = *ss = US"235 Authentication succeeded";
3772 authenticated_by = au;
3776 /* Authentication succeeded, but we failed to expand the set_id string.
3777 Treat this as a temporary error. */
3779 auth_defer_msg = expand_string_message;
3783 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3784 *s = string_sprintf("435 Unable to authenticate at present%s",
3785 auth_defer_user_msg);
3786 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3787 set_id, auth_defer_msg);
3791 *s = *ss = US"501 Invalid base64 data";
3795 *s = *ss = US"501 Authentication cancelled";
3799 *s = *ss = US"553 Initial data not expected";
3803 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3804 *s = US"535 Incorrect authentication data";
3805 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3809 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3810 *s = US"435 Internal error";
3811 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3812 "check", set_id, rc);
3824 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3827 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3829 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3831 rd = Ustrlen(recipient) + 1;
3832 *recipient = rewrite_address_qualify(*recipient, TRUE);
3835 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3837 log_write(L_smtp_syntax_error,
3838 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3839 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3847 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3850 incomplete_transaction_log(US"QUIT");
3853 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3855 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3860 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_CORK, US &on, sizeof(on));
3864 smtp_respond(US"221", 3, TRUE, *user_msgp);
3866 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3869 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3872 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3873 smtp_get_connection_info());
3878 smtp_rset_handler(void)
3881 incomplete_transaction_log(US"RSET");
3882 smtp_printf("250 Reset OK\r\n", FALSE);
3883 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3888 /*************************************************
3889 * Initialize for SMTP incoming message *
3890 *************************************************/
3892 /* This function conducts the initial dialogue at the start of an incoming SMTP
3893 message, and builds a list of recipients. However, if the incoming message
3894 is part of a batch (-bS option) a separate function is called since it would
3895 be messy having tests splattered about all over this function. This function
3896 therefore handles the case where interaction is occurring. The input and output
3897 files are set up in smtp_in and smtp_out.
3899 The global recipients_list is set to point to a vector of recipient_item
3900 blocks, whose number is given by recipients_count. This is extended by the
3901 receive_add_recipient() function. The global variable sender_address is set to
3902 the sender's address. The yield is +1 if a message has been successfully
3903 started, 0 if a QUIT command was encountered or the connection was refused from
3904 the particular host, or -1 if the connection was lost.
3908 Returns: > 0 message successfully started (reached DATA)
3909 = 0 QUIT read or end of file reached or call refused
3914 smtp_setup_msg(void)
3917 BOOL toomany = FALSE;
3918 BOOL discarded = FALSE;
3919 BOOL last_was_rej_mail = FALSE;
3920 BOOL last_was_rcpt = FALSE;
3921 rmark reset_point = store_mark();
3923 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3925 /* Reset for start of new message. We allow one RSET not to be counted as a
3926 nonmail command, for those MTAs that insist on sending it between every
3927 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3928 TLS between messages (an Exim client may do this if it has messages queued up
3929 for the host). Note: we do NOT reset AUTH at this point. */
3931 reset_point = smtp_reset(reset_point);
3932 message_ended = END_NOTSTARTED;
3934 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3936 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3937 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3938 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3940 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3943 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3945 had_command_sigterm = 0;
3946 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3948 /* Batched SMTP is handled in a different function. */
3950 if (smtp_batched_input) return smtp_setup_batch_msg();
3952 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3953 value. The values are 2 larger than the required yield of the function. */
3957 const uschar **argv;
3958 uschar *etrn_command;
3959 uschar *etrn_serialize_key;
3961 uschar *log_msg, *smtp_code;
3962 uschar *user_msg = NULL;
3963 uschar *recipient = NULL;
3964 uschar *hello = NULL;
3966 BOOL was_rej_mail = FALSE;
3967 BOOL was_rcpt = FALSE;
3968 void (*oldsignal)(int);
3970 int start, end, sender_domain, recipient_domain;
3973 uschar *orcpt = NULL;
3978 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3979 if ( tls_in.active.sock >= 0
3981 && tls_in.certificate_verified
3982 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3985 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3987 for (auth_instance * au = auths; au; au = au->next)
3988 if (strcmpic(US"tls", au->driver_name) == 0)
3991 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3992 &user_msg, &log_msg)) != OK
3994 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3997 smtp_cmd_data = NULL;
3999 if (smtp_in_auth(au, &s, &ss) == OK)
4000 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
4002 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
4010 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
4011 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4012 US &off, sizeof(off));
4015 switch(smtp_read_command(
4016 #ifndef DISABLE_PIPE_CONNECT
4017 !fl.pipe_connect_acceptable,
4021 GETC_BUFFER_UNLIMITED))
4023 /* The AUTH command is not permitted to occur inside a transaction, and may
4024 occur successfully only once per connection. Actually, that isn't quite
4025 true. When TLS is started, all previous information about a connection must
4026 be discarded, so a new AUTH is permitted at that time.
4028 AUTH may only be used when it has been advertised. However, it seems that
4029 there are clients that send AUTH when it hasn't been advertised, some of
4030 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4031 So there's a get-out that allows this to happen.
4033 AUTH is initially labelled as a "nonmail command" so that one occurrence
4034 doesn't get counted. We change the label here so that multiple failing
4035 AUTHS will eventually hit the nonmail threshold. */
4039 authentication_failed = TRUE;
4040 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4042 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4044 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4045 US"AUTH command used when not advertised");
4048 if (sender_host_authenticated)
4050 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4051 US"already authenticated");
4056 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4057 US"not permitted in mail transaction");
4064 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4065 &user_msg, &log_msg)) != OK
4068 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4072 /* Find the name of the requested authentication mechanism. */
4075 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
4077 if (!isalnum(c) && c != '-' && c != '_')
4079 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4080 US"invalid character in authentication mechanism name");
4086 /* If not at the end of the line, we must be at white space. Terminate the
4087 name and move the pointer on to any data that may be present. */
4089 if (*smtp_cmd_data != 0)
4091 *smtp_cmd_data++ = 0;
4092 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4095 /* Search for an authentication mechanism which is configured for use
4096 as a server and which has been advertised (unless, sigh, allow_auth_
4097 unadvertised is set). */
4101 for (au = auths; au; au = au->next)
4102 if (strcmpic(s, au->public_name) == 0 && au->server &&
4103 (au->advertised || f.allow_auth_unadvertised))
4108 c = smtp_in_auth(au, &s, &ss);
4110 smtp_printf("%s\r\n", FALSE, s);
4112 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4113 au->name, host_and_ident(FALSE), ss);
4116 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4117 string_sprintf("%s authentication mechanism not supported", s));
4120 break; /* AUTH_CMD */
4122 /* The HELO/EHLO commands are permitted to appear in the middle of a
4123 session as well as at the beginning. They have the effect of a reset in
4124 addition to their other functions. Their absence at the start cannot be
4125 taken to be an error.
4129 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4130 or 502 failure replies MUST be returned as appropriate. The SMTP
4131 server MUST stay in the same state after transmitting these replies
4132 that it was in before the EHLO was received.
4134 Therefore, we do not do the reset until after checking the command for
4135 acceptability. This change was made for Exim release 4.11. Previously
4136 it did the reset first. */
4149 HELO_EHLO: /* Common code for HELO and EHLO */
4150 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4151 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4153 /* Reject the HELO if its argument was invalid or non-existent. A
4154 successful check causes the argument to be saved in malloc store. */
4156 if (!check_helo(smtp_cmd_data))
4158 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4160 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4161 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4162 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4163 string_printing(smtp_cmd_argument));
4165 if (++synprot_error_count > smtp_max_synprot_errors)
4167 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4168 "syntax or protocol errors (last command was \"%s\", %s)",
4169 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4170 string_from_gstring(s_connhad_log(NULL))
4178 /* If sender_host_unknown is true, we have got here via the -bs interface,
4179 not called from inetd. Otherwise, we are running an IP connection and the
4180 host address will be set. If the helo name is the primary name of this
4181 host and we haven't done a reverse lookup, force one now. If helo_required
4182 is set, ensure that the HELO name matches the actual host. If helo_verify
4183 is set, do the same check, but softly. */
4185 if (!f.sender_host_unknown)
4187 BOOL old_helo_verified = f.helo_verified;
4188 uschar *p = smtp_cmd_data;
4190 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4193 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4194 because otherwise the log can be confusing. */
4196 if ( !sender_host_name
4197 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4198 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4199 (void)host_name_lookup();
4201 /* Rebuild the fullhost info to include the HELO name (and the real name
4202 if it was looked up.) */
4204 host_build_sender_fullhost(); /* Rebuild */
4205 set_process_info("handling%s incoming connection from %s",
4206 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4208 /* Verify if configured. This doesn't give much security, but it does
4209 make some people happy to be able to do it. If helo_required is set,
4210 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4211 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4212 now obsolescent, since the verification can now be requested selectively
4215 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4216 if (fl.helo_required || fl.helo_verify)
4218 BOOL tempfail = !smtp_verify_helo();
4219 if (!f.helo_verified)
4221 if (fl.helo_required)
4223 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4224 tempfail? 451 : 550, hello);
4225 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4226 tempfail? "temporarily " : "",
4227 hello, sender_helo_name, host_and_ident(FALSE));
4228 f.helo_verified = old_helo_verified;
4229 break; /* End of HELO/EHLO processing */
4231 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4232 "helo_try_verify_hosts\n", hello);
4238 /* set up SPF context */
4239 spf_conn_init(sender_helo_name, sender_host_address);
4242 /* Apply an ACL check if one is defined; afterwards, recheck
4243 synchronization in case the client started sending in a delay. */
4246 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4247 &user_msg, &log_msg)) != OK)
4249 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4250 sender_helo_name = NULL;
4251 host_build_sender_fullhost(); /* Rebuild */
4254 #ifndef DISABLE_PIPE_CONNECT
4255 else if (!fl.pipe_connect_acceptable && !check_sync())
4257 else if (!check_sync())
4261 /* Generate an OK reply. The default string includes the ident if present,
4262 and also the IP address if present. Reflecting back the ident is intended
4263 as a deterrent to mail forgers. For maximum efficiency, and also because
4264 some broken systems expect each response to be in a single packet, arrange
4265 that the entire reply is sent in one write(). */
4267 fl.auth_advertised = FALSE;
4268 f.smtp_in_pipelining_advertised = FALSE;
4270 fl.tls_advertised = FALSE;
4272 fl.dsn_advertised = FALSE;
4274 fl.smtputf8_advertised = FALSE;
4277 smtp_code = US"250 "; /* Default response code plus space*/
4280 /* sender_host_name below will be tainted, so save on copy when we hit it */
4281 g = string_get_tainted(24, TRUE);
4282 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4284 smtp_active_hostname,
4285 sender_ident ? sender_ident : US"",
4286 sender_ident ? US" at " : US"",
4287 sender_host_name ? sender_host_name : sender_helo_name);
4289 if (sender_host_address)
4290 g = string_fmt_append(g, " [%s]", sender_host_address);
4293 /* A user-supplied EHLO greeting may not contain more than one line. Note
4294 that the code returned by smtp_message_code() includes the terminating
4295 whitespace character. */
4301 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4302 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4303 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4305 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4306 "newlines: message truncated: %s", string_printing(s));
4309 g = string_cat(NULL, s);
4312 g = string_catn(g, US"\r\n", 2);
4314 /* If we received EHLO, we must create a multiline response which includes
4315 the functions supported. */
4321 /* I'm not entirely happy with this, as an MTA is supposed to check
4322 that it has enough room to accept a message of maximum size before
4323 it sends this. However, there seems little point in not sending it.
4324 The actual size check happens later at MAIL FROM time. By postponing it
4325 till then, VRFY and EXPN can be used after EHLO when space is short. */
4327 if (thismessage_size_limit > 0)
4328 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4329 thismessage_size_limit);
4332 g = string_catn(g, smtp_code, 3);
4333 g = string_catn(g, US"-SIZE\r\n", 7);
4336 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4337 clean; if it has an 8-bit character in its hand, it just sends it. It
4338 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4339 However, some users want this option simply in order to stop MUAs
4340 mangling messages that contain top-bit-set characters. It is therefore
4341 provided as an option. */
4343 if (accept_8bitmime)
4345 g = string_catn(g, smtp_code, 3);
4346 g = string_catn(g, US"-8BITMIME\r\n", 11);
4349 /* Advertise DSN support if configured to do so. */
4350 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4352 g = string_catn(g, smtp_code, 3);
4353 g = string_catn(g, US"-DSN\r\n", 6);
4354 fl.dsn_advertised = TRUE;
4357 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4358 permitted to issue them; a check is made when any host actually tries. */
4362 g = string_catn(g, smtp_code, 3);
4363 g = string_catn(g, US"-ETRN\r\n", 7);
4367 g = string_catn(g, smtp_code, 3);
4368 g = string_catn(g, US"-VRFY\r\n", 7);
4372 g = string_catn(g, smtp_code, 3);
4373 g = string_catn(g, US"-EXPN\r\n", 7);
4376 /* Exim is quite happy with pipelining, so let the other end know that
4377 it is safe to use it, unless advertising is disabled. */
4379 if ( f.pipelining_enable
4380 && verify_check_host(&pipelining_advertise_hosts) == OK)
4382 g = string_catn(g, smtp_code, 3);
4383 g = string_catn(g, US"-PIPELINING\r\n", 13);
4384 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4385 f.smtp_in_pipelining_advertised = TRUE;
4387 #ifndef DISABLE_PIPE_CONNECT
4388 if (fl.pipe_connect_acceptable)
4390 f.smtp_in_early_pipe_advertised = TRUE;
4391 g = string_catn(g, smtp_code, 3);
4392 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4398 /* If any server authentication mechanisms are configured, advertise
4399 them if the current host is in auth_advertise_hosts. The problem with
4400 advertising always is that some clients then require users to
4401 authenticate (and aren't configurable otherwise) even though it may not
4402 be necessary (e.g. if the host is in host_accept_relay).
4404 RFC 2222 states that SASL mechanism names contain only upper case
4405 letters, so output the names in upper case, though we actually recognize
4406 them in either case in the AUTH command. */
4410 && !sender_host_authenticated
4412 && verify_check_host(&auth_advertise_hosts) == OK
4416 for (auth_instance * au = auths; au; au = au->next)
4418 au->advertised = FALSE;
4421 DEBUG(D_auth+D_expand) debug_printf_indent(
4422 "Evaluating advertise_condition for %s %s athenticator\n",
4423 au->name, au->public_name);
4424 if ( !au->advertise_condition
4425 || expand_check_condition(au->advertise_condition, au->name,
4432 g = string_catn(g, smtp_code, 3);
4433 g = string_catn(g, US"-AUTH", 5);
4435 fl.auth_advertised = TRUE;
4438 g = string_catn(g, US" ", 1);
4439 g = string_cat (g, au->public_name);
4440 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4441 au->advertised = TRUE;
4446 if (!first) g = string_catn(g, US"\r\n", 2);
4449 /* RFC 3030 CHUNKING */
4451 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4453 g = string_catn(g, smtp_code, 3);
4454 g = string_catn(g, US"-CHUNKING\r\n", 11);
4455 f.chunking_offered = TRUE;
4456 chunking_state = CHUNKING_OFFERED;
4459 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4460 if it has been included in the binary, and the host matches
4461 tls_advertise_hosts. We must *not* advertise if we are already in a
4462 secure connection. */
4465 if (tls_in.active.sock < 0 &&
4466 verify_check_host(&tls_advertise_hosts) != FAIL)
4468 g = string_catn(g, smtp_code, 3);
4469 g = string_catn(g, US"-STARTTLS\r\n", 11);
4470 fl.tls_advertised = TRUE;
4474 #ifndef DISABLE_PRDR
4475 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4478 g = string_catn(g, smtp_code, 3);
4479 g = string_catn(g, US"-PRDR\r\n", 7);
4484 if ( accept_8bitmime
4485 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4487 g = string_catn(g, smtp_code, 3);
4488 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4489 fl.smtputf8_advertised = TRUE;
4493 /* Finish off the multiline reply with one that is always available. */
4495 g = string_catn(g, smtp_code, 3);
4496 g = string_catn(g, US" HELP\r\n", 7);
4499 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4503 if (tls_in.active.sock >= 0)
4504 (void)tls_write(NULL, g->s, g->ptr,
4505 # ifndef DISABLE_PIPE_CONNECT
4506 fl.pipe_connect_acceptable && pipeline_connect_sends());
4514 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4520 (void) string_from_gstring(g);
4521 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4522 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4523 debug_printf("SMTP>> %s", g->s);
4525 fl.helo_seen = TRUE;
4527 /* Reset the protocol and the state, abandoning any previous message. */
4529 (sender_host_address ? protocols : protocols_local)
4531 ? pextend + (sender_host_authenticated ? pauthed : 0)
4533 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4535 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4536 reset_point = smtp_reset(reset_point);
4538 break; /* HELO/EHLO */
4541 /* The MAIL command requires an address as an operand. All we do
4542 here is to parse it for syntactic correctness. The form "<>" is
4543 a special case which converts into an empty string. The start/end
4544 pointers in the original are not used further for this address, as
4545 it is the canonical extracted address which is all that is kept. */
4549 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4550 was_rej_mail = TRUE; /* Reset if accepted */
4551 env_mail_type_t * mail_args; /* Sanity check & validate args */
4553 if (fl.helo_required && !fl.helo_seen)
4555 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4556 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4557 "HELO/EHLO given", host_and_ident(FALSE));
4563 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4564 US"sender already given");
4568 if (!*smtp_cmd_data)
4570 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4571 US"MAIL must have an address operand");
4575 /* Check to see if the limit for messages per connection would be
4576 exceeded by accepting further messages. */
4578 if (smtp_accept_max_per_connection > 0 &&
4579 smtp_mailcmd_count > smtp_accept_max_per_connection)
4581 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4582 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4583 "messages in one connection", host_and_ident(TRUE));
4587 /* Reset for start of message - even if this is going to fail, we
4588 obviously need to throw away any previous data. */
4590 cancel_cutthrough_connection(TRUE, US"MAIL received");
4591 reset_point = smtp_reset(reset_point);
4593 sender_data = recipient_data = NULL;
4595 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4597 if (fl.esmtp) for(;;)
4599 uschar *name, *value, *end;
4600 unsigned long int size;
4601 BOOL arg_error = FALSE;
4603 if (!extract_option(&name, &value)) break;
4605 for (mail_args = env_mail_type_list;
4606 mail_args->value != ENV_MAIL_OPT_NULL;
4609 if (strcmpic(name, mail_args->name) == 0)
4611 if (mail_args->need_value && strcmpic(value, US"") == 0)
4614 switch(mail_args->value)
4616 /* Handle SIZE= by reading the value. We don't do the check till later,
4617 in order to be able to log the sender address on failure. */
4618 case ENV_MAIL_OPT_SIZE:
4619 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4621 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4623 message_size = (int)size;
4629 /* If this session was initiated with EHLO and accept_8bitmime is set,
4630 Exim will have indicated that it supports the BODY=8BITMIME option. In
4631 fact, it does not support this according to the RFCs, in that it does not
4632 take any special action for forwarding messages containing 8-bit
4633 characters. That is why accept_8bitmime is not the default setting, but
4634 some sites want the action that is provided. We recognize both "8BITMIME"
4635 and "7BIT" as body types, but take no action. */
4636 case ENV_MAIL_OPT_BODY:
4637 if (accept_8bitmime) {
4638 if (strcmpic(value, US"8BITMIME") == 0)
4640 else if (strcmpic(value, US"7BIT") == 0)
4645 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4646 US"invalid data for BODY");
4649 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4655 /* Handle the two DSN options, but only if configured to do so (which
4656 will have caused "DSN" to be given in the EHLO response). The code itself
4657 is included only if configured in at build time. */
4659 case ENV_MAIL_OPT_RET:
4660 if (fl.dsn_advertised)
4662 /* Check if RET has already been set */
4665 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4666 US"RET can be specified once only");
4669 dsn_ret = strcmpic(value, US"HDRS") == 0
4671 : strcmpic(value, US"FULL") == 0
4674 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4675 /* Check for invalid invalid value, and exit with error */
4678 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4679 US"Value for RET is invalid");
4684 case ENV_MAIL_OPT_ENVID:
4685 if (fl.dsn_advertised)
4687 /* Check if the dsn envid has been already set */
4690 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4691 US"ENVID can be specified once only");
4694 dsn_envid = string_copy(value);
4695 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4699 /* Handle the AUTH extension. If the value given is not "<>" and either
4700 the ACL says "yes" or there is no ACL but the sending host is
4701 authenticated, we set it up as the authenticated sender. However, if the
4702 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4703 the condition is met. The value of AUTH is an xtext, which means that +,
4704 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4706 case ENV_MAIL_OPT_AUTH:
4707 if (Ustrcmp(value, "<>") != 0)
4712 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4714 /* Put back terminator overrides for error message */
4717 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4718 US"invalid data for AUTH");
4721 if (!acl_smtp_mailauth)
4723 ignore_msg = US"client not authenticated";
4724 rc = sender_host_authenticated ? OK : FAIL;
4728 ignore_msg = US"rejected by ACL";
4729 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4730 &user_msg, &log_msg);
4736 if (authenticated_by == NULL ||
4737 authenticated_by->mail_auth_condition == NULL ||
4738 expand_check_condition(authenticated_by->mail_auth_condition,
4739 authenticated_by->name, US"authenticator"))
4740 break; /* Accept the AUTH */
4742 ignore_msg = US"server_mail_auth_condition failed";
4743 if (authenticated_id != NULL)
4744 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4745 ignore_msg, authenticated_id);
4750 authenticated_sender = NULL;
4751 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4752 value, host_and_ident(TRUE), ignore_msg);
4755 /* Should only get DEFER or ERROR here. Put back terminator
4756 overrides for error message */
4761 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4768 #ifndef DISABLE_PRDR
4769 case ENV_MAIL_OPT_PRDR:
4771 prdr_requested = TRUE;
4776 case ENV_MAIL_OPT_UTF8:
4777 if (!fl.smtputf8_advertised)
4779 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4780 US"SMTPUTF8 used when not advertised");
4784 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4785 message_smtputf8 = allow_utf8_domains = TRUE;
4786 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4788 int old_pool = store_pool;
4789 store_pool = POOL_PERM;
4790 received_protocol = string_sprintf("utf8%s", received_protocol);
4791 store_pool = old_pool;
4796 /* No valid option. Stick back the terminator characters and break
4797 the loop. Do the name-terminator second as extract_option sets
4798 value==name when it found no equal-sign.
4799 An error for a malformed address will occur. */
4800 case ENV_MAIL_OPT_NULL:
4808 /* Break out of for loop if switch() had bad argument or
4809 when start of the email address is reached */
4810 if (arg_error) break;
4813 /* If we have passed the threshold for rate limiting, apply the current
4814 delay, and update it for next time, provided this is a limited host. */
4816 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4817 verify_check_host(&smtp_ratelimit_hosts) == OK)
4819 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4820 smtp_delay_mail/1000.0);
4821 millisleep((int)smtp_delay_mail);
4822 smtp_delay_mail *= smtp_rlm_factor;
4823 if (smtp_delay_mail > (double)smtp_rlm_limit)
4824 smtp_delay_mail = (double)smtp_rlm_limit;
4827 /* Now extract the address, first applying any SMTP-time rewriting. The
4828 TRUE flag allows "<>" as a sender address. */
4830 raw_sender = rewrite_existflags & rewrite_smtp
4831 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4832 global_rewrite_rules)
4836 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4841 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4845 sender_address = raw_sender;
4847 /* If there is a configured size limit for mail, check that this message
4848 doesn't exceed it. The check is postponed to this point so that the sender
4851 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4853 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4854 log_write(L_size_reject,
4855 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4856 "message too big: size%s=%d max=%d",
4858 host_and_ident(TRUE),
4859 (message_size == INT_MAX)? ">" : "",
4861 thismessage_size_limit);
4862 sender_address = NULL;
4866 /* Check there is enough space on the disk unless configured not to.
4867 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4868 plus the current message - i.e. we accept the message only if it won't
4869 reduce the space below the threshold. Add 5000 to the size to allow for
4870 overheads such as the Received: line and storing of recipients, etc.
4871 By putting the check here, even when SIZE is not given, it allow VRFY
4872 and EXPN etc. to be used when space is short. */
4874 if (!receive_check_fs(
4875 smtp_check_spool_space && message_size >= 0
4876 ? message_size + 5000 : 0))
4878 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4879 sender_address = NULL;
4883 /* If sender_address is unqualified, reject it, unless this is a locally
4884 generated message, or the sending host or net is permitted to send
4885 unqualified addresses - typically local machines behaving as MUAs -
4886 in which case just qualify the address. The flag is set above at the start
4887 of the SMTP connection. */
4889 if (!sender_domain && *sender_address)
4890 if (f.allow_unqualified_sender)
4892 sender_domain = Ustrlen(sender_address) + 1;
4893 sender_address = rewrite_address_qualify(sender_address, FALSE);
4894 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4899 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4901 log_write(L_smtp_syntax_error,
4902 LOG_MAIN|LOG_REJECT,
4903 "unqualified sender rejected: <%s> %s%s",
4905 host_and_ident(TRUE),
4907 sender_address = NULL;
4911 /* Apply an ACL check if one is defined, before responding. Afterwards,
4912 when pipelining is not advertised, do another sync check in case the ACL
4913 delayed and the client started sending in the meantime. */
4917 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4918 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4924 if (rc == OK || rc == DISCARD)
4926 BOOL more = pipeline_response();
4929 smtp_printf("%s%s%s", more, US"250 OK",
4930 #ifndef DISABLE_PRDR
4931 prdr_requested ? US", PRDR Requested" : US"",
4938 #ifndef DISABLE_PRDR
4940 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4942 smtp_user_msg(US"250", user_msg);
4944 smtp_delay_rcpt = smtp_rlr_base;
4945 f.recipients_discarded = (rc == DISCARD);
4946 was_rej_mail = FALSE;
4950 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
4951 sender_address = NULL;
4956 /* The RCPT command requires an address as an operand. There may be any
4957 number of RCPT commands, specifying multiple recipients. We build them all
4958 into a data structure. The start/end values given by parse_extract_address
4959 are not used, as we keep only the extracted address. */
4964 was_rcpt = fl.rcpt_in_progress = TRUE;
4966 /* There must be a sender address; if the sender was rejected and
4967 pipelining was advertised, we assume the client was pipelining, and do not
4968 count this as a protocol error. Reset was_rej_mail so that further RCPTs
4969 get the same treatment. */
4971 if (sender_address == NULL)
4973 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
4975 smtp_printf("503 sender not yet given\r\n", FALSE);
4976 was_rej_mail = TRUE;
4980 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4981 US"sender not yet given");
4982 was_rcpt = FALSE; /* Not a valid RCPT */
4988 /* Check for an operand */
4990 if (smtp_cmd_data[0] == 0)
4992 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4993 US"RCPT must have an address operand");
4998 /* Set the DSN flags orcpt and dsn_flags from the session*/
5002 if (fl.esmtp) for(;;)
5004 uschar *name, *value;
5006 if (!extract_option(&name, &value))
5009 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5011 /* Check whether orcpt has been already set */
5014 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5015 US"ORCPT can be specified once only");
5018 orcpt = string_copy(value);
5019 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5022 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5024 /* Check if the notify flags have been already set */
5027 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5028 US"NOTIFY can be specified once only");
5031 if (strcmpic(value, US"NEVER") == 0)
5032 dsn_flags |= rf_notify_never;
5039 while (*pp != 0 && *pp != ',') pp++;
5040 if (*pp == ',') *pp++ = 0;
5041 if (strcmpic(p, US"SUCCESS") == 0)
5043 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5044 dsn_flags |= rf_notify_success;
5046 else if (strcmpic(p, US"FAILURE") == 0)
5048 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5049 dsn_flags |= rf_notify_failure;
5051 else if (strcmpic(p, US"DELAY") == 0)
5053 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5054 dsn_flags |= rf_notify_delay;
5058 /* Catch any strange values */
5059 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5060 US"Invalid value for NOTIFY parameter");
5065 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5069 /* Unknown option. Stick back the terminator characters and break
5070 the loop. An error for a malformed address will occur. */
5074 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5081 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5082 as a recipient address */
5084 recipient = rewrite_existflags & rewrite_smtp
5085 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5086 global_rewrite_rules)
5089 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5090 &recipient_domain, FALSE)))
5092 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5097 /* If the recipient address is unqualified, reject it, unless this is a
5098 locally generated message. However, unqualified addresses are permitted
5099 from a configured list of hosts and nets - typically when behaving as
5100 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5101 really. The flag is set at the start of the SMTP connection.
5103 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5104 assumed this meant "reserved local part", but the revision of RFC 821 and
5105 friends now makes it absolutely clear that it means *mailbox*. Consequently
5106 we must always qualify this address, regardless. */
5108 if (!recipient_domain)
5109 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5116 /* Check maximum allowed */
5118 if (rcpt_count > recipients_max && recipients_max > 0)
5120 if (recipients_max_reject)
5123 smtp_printf("552 too many recipients\r\n", FALSE);
5125 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5126 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5131 smtp_printf("452 too many recipients\r\n", FALSE);
5133 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5134 "temporarily rejected: sender=<%s> %s", sender_address,
5135 host_and_ident(TRUE));
5142 /* If we have passed the threshold for rate limiting, apply the current
5143 delay, and update it for next time, provided this is a limited host. */
5145 if (rcpt_count > smtp_rlr_threshold &&
5146 verify_check_host(&smtp_ratelimit_hosts) == OK)
5148 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5149 smtp_delay_rcpt/1000.0);
5150 millisleep((int)smtp_delay_rcpt);
5151 smtp_delay_rcpt *= smtp_rlr_factor;
5152 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5153 smtp_delay_rcpt = (double)smtp_rlr_limit;
5156 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5157 for them. Otherwise, check the access control list for this recipient. As
5158 there may be a delay in this, re-check for a synchronization error
5159 afterwards, unless pipelining was advertised. */
5161 if (f.recipients_discarded)
5164 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5166 && !f.smtp_in_pipelining_advertised && !check_sync())
5169 /* The ACL was happy */
5173 BOOL more = pipeline_response();
5176 smtp_user_msg(US"250", user_msg);
5178 smtp_printf("250 Accepted\r\n", more);
5179 receive_add_recipient(recipient, -1);
5181 /* Set the dsn flags in the recipients_list */
5182 recipients_list[recipients_count-1].orcpt = orcpt;
5183 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5185 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5186 recipients_list[recipients_count-1].orcpt,
5187 recipients_list[recipients_count-1].dsn_flags); */
5190 /* The recipient was discarded */
5192 else if (rc == DISCARD)
5195 smtp_user_msg(US"250", user_msg);
5197 smtp_printf("250 Accepted\r\n", FALSE);
5200 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5201 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5202 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5203 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5204 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5207 /* Either the ACL failed the address, or it was deferred. */
5211 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5212 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5217 /* The DATA command is legal only if it follows successful MAIL FROM
5218 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5219 not counted as a protocol error if it follows RCPT (which must have been
5220 rejected if there are no recipients.) This function is complete when a
5221 valid DATA command is encountered.
5223 Note concerning the code used: RFC 2821 says this:
5225 - If there was no MAIL, or no RCPT, command, or all such commands
5226 were rejected, the server MAY return a "command out of sequence"
5227 (503) or "no valid recipients" (554) reply in response to the
5230 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5231 because it is the same whether pipelining is in use or not.
5233 If all the RCPT commands that precede DATA provoked the same error message
5234 (often indicating some kind of system error), it is helpful to include it
5235 with the DATA rejection (an idea suggested by Tony Finch). */
5242 if (chunking_state != CHUNKING_OFFERED)
5244 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5245 US"BDAT command used when CHUNKING not advertised");
5249 /* grab size, endmarker */
5251 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5253 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5254 US"missing size for BDAT command");
5257 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5258 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5259 chunking_data_left = chunking_datasize;
5260 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5261 (int)chunking_state, chunking_data_left);
5263 /* push the current receive_* function on the "stack", and
5264 replace them by bdat_getc(), which in turn will use the lwr_receive_*
5265 functions to do the dirty work. */
5266 lwr_receive_getc = receive_getc;
5267 lwr_receive_getbuf = receive_getbuf;
5268 lwr_receive_ungetc = receive_ungetc;
5270 receive_getc = bdat_getc;
5271 receive_ungetc = bdat_ungetc;
5282 DATA_BDAT: /* Common code for DATA and BDAT */
5283 #ifndef DISABLE_PIPE_CONNECT
5284 fl.pipe_connect_acceptable = FALSE;
5286 if (!discarded && recipients_count <= 0)
5288 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5290 uschar *code = US"503";
5291 int len = Ustrlen(rcpt_smtp_response);
5292 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5294 /* Responses from smtp_printf() will have \r\n on the end */
5295 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5296 rcpt_smtp_response[len-2] = 0;
5297 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5299 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5300 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5301 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5303 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5304 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5305 ? US"valid RCPT command must precede DATA"
5306 : US"valid RCPT command must precede BDAT");
5308 if (chunking_state > CHUNKING_OFFERED)
5313 if (toomany && recipients_max_reject)
5315 sender_address = NULL; /* This will allow a new MAIL without RSET */
5316 sender_address_unrewritten = NULL;
5317 smtp_printf("554 Too many recipients\r\n", FALSE);
5321 if (chunking_state > CHUNKING_OFFERED)
5322 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5325 /* If there is an ACL, re-check the synchronization afterwards, since the
5326 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5327 to get the DATA command sent. */
5329 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5333 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5334 f.enable_dollar_recipients = TRUE;
5335 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5337 f.enable_dollar_recipients = FALSE;
5338 if (rc == OK && !check_sync())
5342 { /* Either the ACL failed the address, or it was deferred. */
5343 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5349 smtp_user_msg(US"354", user_msg);
5352 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5356 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5357 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5358 US &on, sizeof(on));
5361 message_ended = END_NOTENDED; /* Indicate in middle of data */
5372 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5373 &start, &end, &recipient_domain, FALSE)))
5375 smtp_printf("501 %s\r\n", FALSE, errmess);
5379 if (!recipient_domain)
5380 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5384 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5385 &user_msg, &log_msg)) != OK)
5386 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5390 address_item * addr = deliver_make_addr(address, FALSE);
5392 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5393 -1, -1, NULL, NULL, NULL))
5396 s = string_sprintf("250 <%s> is deliverable", address);
5400 s = (addr->user_message != NULL)?
5401 string_sprintf("451 <%s> %s", address, addr->user_message) :
5402 string_sprintf("451 Cannot resolve <%s> at this time", address);
5406 s = (addr->user_message != NULL)?
5407 string_sprintf("550 <%s> %s", address, addr->user_message) :
5408 string_sprintf("550 <%s> is not deliverable", address);
5409 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5410 smtp_cmd_argument, host_and_ident(TRUE));
5414 smtp_printf("%s\r\n", FALSE, s);
5422 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5424 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5427 BOOL save_log_testing_mode = f.log_testing_mode;
5428 f.address_test_mode = f.log_testing_mode = TRUE;
5429 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5430 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5432 f.address_test_mode = FALSE;
5433 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5442 if (!fl.tls_advertised)
5444 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5445 US"STARTTLS command used when not advertised");
5449 /* Apply an ACL check if one is defined */
5451 if ( acl_smtp_starttls
5452 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5453 &user_msg, &log_msg)) != OK
5456 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5460 /* RFC 2487 is not clear on when this command may be sent, though it
5461 does state that all information previously obtained from the client
5462 must be discarded if a TLS session is started. It seems reasonable to
5463 do an implied RSET when STARTTLS is received. */
5465 incomplete_transaction_log(US"STARTTLS");
5466 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5467 reset_point = smtp_reset(reset_point);
5469 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5471 /* There's an attack where more data is read in past the STARTTLS command
5472 before TLS is negotiated, then assumed to be part of the secure session
5473 when used afterwards; we use segregated input buffers, so are not
5474 vulnerable, but we want to note when it happens and, for sheer paranoia,
5475 ensure that the buffer is "wiped".
5476 Pipelining sync checks will normally have protected us too, unless disabled
5477 by configuration. */
5479 if (receive_smtp_buffered())
5482 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5483 if (tls_in.active.sock < 0)
5484 smtp_inend = smtp_inptr = smtp_inbuffer;
5485 /* and if TLS is already active, tls_server_start() should fail */
5488 /* There is nothing we value in the input buffer and if TLS is successfully
5489 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5490 fresh content into it. The buffer contains arbitrary content from an
5491 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5492 It seems safest to just wipe away the content rather than leave it as a
5493 target to jump to. */
5495 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5497 /* Attempt to start up a TLS session, and if successful, discard all
5498 knowledge that was obtained previously. At least, that's what the RFC says,
5499 and that's what happens by default. However, in order to work round YAEB,
5500 there is an option to remember the esmtp state. Sigh.
5502 We must allow for an extra EHLO command and an extra AUTH command after
5503 STARTTLS that don't add to the nonmail command count. */
5506 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5508 if (!tls_remember_esmtp)
5509 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5510 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5511 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5512 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5513 if (sender_helo_name)
5515 sender_helo_name = NULL;
5516 host_build_sender_fullhost(); /* Rebuild */
5517 set_process_info("handling incoming TLS connection from %s",
5518 host_and_ident(FALSE));
5521 (sender_host_address ? protocols : protocols_local)
5523 ? pextend + (sender_host_authenticated ? pauthed : 0)
5525 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5528 sender_host_auth_pubname = sender_host_authenticated = NULL;
5529 authenticated_id = NULL;
5530 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5531 DEBUG(D_tls) debug_printf("TLS active\n");
5532 break; /* Successful STARTTLS */
5535 (void) smtp_log_tls_fail(s);
5537 /* Some local configuration problem was discovered before actually trying
5538 to do a TLS handshake; give a temporary error. */
5542 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5546 /* Hard failure. Reject everything except QUIT or closed connection. One
5547 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5548 set, but we must still reject all incoming commands. Another is a handshake
5549 failure - and there may some encrypted data still in the pipe to us, which we
5550 see as garbage commands. */
5552 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5553 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5556 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5557 smtp_get_connection_info());
5558 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5562 /* It is perhaps arguable as to which exit ACL should be called here,
5563 but as it is probably a situation that almost never arises, it
5564 probably doesn't matter. We choose to call the real QUIT ACL, which in
5565 some sense is perhaps "right". */
5570 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5571 &log_msg)) == ERROR))
5572 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5575 smtp_respond(US"221", 3, TRUE, user_msg);
5577 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5578 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5579 smtp_get_connection_info());
5584 smtp_printf("554 Security failure\r\n", FALSE);
5587 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5592 /* The ACL for QUIT is provided for gathering statistical information or
5593 similar; it does not affect the response code, but it can supply a custom
5597 smtp_quit_handler(&user_msg, &log_msg);
5603 smtp_rset_handler();
5604 cancel_cutthrough_connection(TRUE, US"RSET received");
5605 reset_point = smtp_reset(reset_point);
5612 smtp_printf("250 OK\r\n", FALSE);
5616 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5617 used, a check will be done for permitted hosts. Show STARTTLS only if not
5618 already in a TLS session and if it would be advertised in the EHLO
5623 smtp_printf("214-Commands supported:\r\n", TRUE);
5627 Ustrcat(buffer, US" AUTH");
5629 if (tls_in.active.sock < 0 &&
5630 verify_check_host(&tls_advertise_hosts) != FAIL)
5631 Ustrcat(buffer, US" STARTTLS");
5633 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5634 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5635 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5636 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5637 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5638 smtp_printf("214%s\r\n", FALSE, buffer);
5644 incomplete_transaction_log(US"connection lost");
5645 smtp_notquit_exit(US"connection-lost", US"421",
5646 US"%s lost input connection", smtp_active_hostname);
5648 /* Don't log by default unless in the middle of a message, as some mailers
5649 just drop the call rather than sending QUIT, and it clutters up the logs.
5652 if (sender_address || recipients_count > 0)
5653 log_write(L_lost_incoming_connection, LOG_MAIN,
5654 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5655 f.sender_host_unknown ? "EOF" : "disconnection",
5656 f.tcp_in_fastopen_logged
5659 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5661 host_and_ident(FALSE), smtp_read_error,
5662 string_timesince(&smtp_connection_start)
5666 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5667 smtp_get_connection_info(),
5668 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5670 string_timesince(&smtp_connection_start)
5681 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5682 US"ETRN is not permitted inside a transaction");
5686 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5687 host_and_ident(FALSE));
5689 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5690 &user_msg, &log_msg)) != OK)
5692 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5696 /* Compute the serialization key for this command. */
5698 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5700 /* If a command has been specified for running as a result of ETRN, we
5701 permit any argument to ETRN. If not, only the # standard form is permitted,
5702 since that is strictly the only kind of ETRN that can be implemented
5703 according to the RFC. */
5705 if (smtp_etrn_command)
5709 etrn_command = smtp_etrn_command;
5710 deliver_domain = smtp_cmd_data;
5711 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5712 US"ETRN processing", &error);
5713 deliver_domain = NULL;
5716 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5718 smtp_printf("458 Internal failure\r\n", FALSE);
5723 /* Else set up to call Exim with the -R option. */
5727 if (*smtp_cmd_data++ != '#')
5729 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5730 US"argument must begin with #");
5733 etrn_command = US"exim -R";
5734 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5735 *queue_name ? 4 : 2,
5736 US"-R", smtp_cmd_data,
5737 US"-MCG", queue_name);
5740 /* If we are host-testing, don't actually do anything. */
5746 debug_printf("ETRN command is: %s\n", etrn_command);
5747 debug_printf("ETRN command execution skipped\n");
5749 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5750 else smtp_user_msg(US"250", user_msg);
5755 /* If ETRN queue runs are to be serialized, check the database to
5756 ensure one isn't already running. */
5758 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5760 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5764 /* Fork a child process and run the command. We don't want to have to
5765 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5766 forking. It should be set that way anyway for external incoming SMTP,
5767 but we save and restore to be tidy. If serialization is required, we
5768 actually run the command in yet another process, so we can wait for it
5769 to complete and then remove the serialization lock. */
5771 oldsignal = signal(SIGCHLD, SIG_IGN);
5773 if ((pid = exim_fork(US"etrn-command")) == 0)
5775 smtp_input = FALSE; /* This process is not associated with the */
5776 (void)fclose(smtp_in); /* SMTP call any more. */
5777 (void)fclose(smtp_out);
5779 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5781 /* If not serializing, do the exec right away. Otherwise, fork down
5782 into another process. */
5784 if ( !smtp_etrn_serialize
5785 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5787 DEBUG(D_exec) debug_print_argv(argv);
5788 exim_nullstd(); /* Ensure std{in,out,err} exist */
5789 execv(CS argv[0], (char *const *)argv);
5790 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5791 etrn_command, strerror(errno));
5792 _exit(EXIT_FAILURE); /* paranoia */
5795 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5796 is, we are in the first subprocess, after forking again. All we can do
5797 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5798 complete, before removing the serialization. */
5801 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5802 "failed: %s", strerror(errno));
5806 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5808 (void)wait(&status);
5809 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5813 enq_end(etrn_serialize_key);
5814 exim_underbar_exit(EXIT_SUCCESS);
5817 /* Back in the top level SMTP process. Check that we started a subprocess
5818 and restore the signal state. */
5822 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5824 smtp_printf("458 Unable to fork process\r\n", FALSE);
5825 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5829 smtp_printf("250 OK\r\n", FALSE);
5831 smtp_user_msg(US"250", user_msg);
5833 signal(SIGCHLD, oldsignal);
5838 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5839 US"unexpected argument data");
5843 /* This currently happens only for NULLs, but could be extended. */
5846 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5847 US"NUL character(s) present (shown as '?')");
5848 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5855 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5856 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5857 c = smtp_inend - smtp_inptr;
5858 if (c > 150) c = 150; /* limit logged amount */
5860 incomplete_transaction_log(US"sync failure");
5861 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5862 "(next input sent too soon: pipelining was%s advertised): "
5863 "rejected \"%s\" %s next input=\"%s\"",
5864 f.smtp_in_pipelining_advertised ? "" : " not",
5865 smtp_cmd_buffer, host_and_ident(TRUE),
5866 string_printing(smtp_inptr));
5867 smtp_notquit_exit(US"synchronization-error", US"554",
5868 US"SMTP synchronization error");
5869 done = 1; /* Pretend eof - drops connection */
5873 case TOO_MANY_NONMAIL_CMD:
5874 s = smtp_cmd_buffer;
5875 while (*s != 0 && !isspace(*s)) s++;
5876 incomplete_transaction_log(US"too many non-mail commands");
5877 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5878 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5879 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5880 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5881 done = 1; /* Pretend eof - drops connection */
5884 #ifdef SUPPORT_PROXY
5885 case PROXY_FAIL_IGNORE_CMD:
5886 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5891 if (unknown_command_count++ >= smtp_max_unknown_commands)
5893 log_write(L_smtp_syntax_error, LOG_MAIN,
5894 "SMTP syntax error in \"%s\" %s %s",
5895 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5896 US"unrecognized command");
5897 incomplete_transaction_log(US"unrecognized command");
5898 smtp_notquit_exit(US"bad-commands", US"500",
5899 US"Too many unrecognized commands");
5901 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5902 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5903 string_printing(smtp_cmd_buffer));
5906 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5907 US"unrecognized command");
5911 /* This label is used by goto's inside loops that want to break out to
5912 the end of the command-processing loop. */
5915 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5916 last_was_rcpt = was_rcpt; /* protocol error handling */
5920 return done - 2; /* Convert yield values */
5926 authres_smtpauth(gstring * g)
5928 if (!sender_host_authenticated)
5931 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5933 if (Ustrcmp(sender_host_auth_pubname, "tls") != 0)
5934 g = string_append(g, 2, US") smtp.auth=", authenticated_id);
5935 else if (authenticated_id)
5936 g = string_append(g, 2, US") x509.auth=", authenticated_id);
5938 g = string_catn(g, US") reason=x509.auth", 17);
5940 if (authenticated_sender)
5941 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
5949 /* End of smtp_in.c */