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 static 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 /* Forward declarations */
597 static inline void bdat_push_receive_functions(void);
598 static inline void bdat_pop_receive_functions(void);
601 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
602 previous BDAT chunk and getting new ones when we run out. Uses the
603 underlying smtp_getc or tls_getc both for that and for getting the
604 (buffered) data byte. EOD signals (an expected) no further data.
605 ERR signals a protocol error, and EOF a closed input stream.
607 Called from read_bdat_smtp() in receive.c for the message body, but also
608 by the headers read loop in receive_msg(); manipulates chunking_state
609 to handle the BDAT command/response.
610 Placed here due to the correlation with the above smtp_getc(), which it wraps,
611 and also by the need to do smtp command/response handling.
613 Arguments: lim (ignored)
614 Returns: the next character or ERR, EOD or EOF
618 bdat_getc(unsigned lim)
620 uschar * user_msg = NULL;
629 if (chunking_data_left > 0)
630 return lwr_receive_getc(chunking_data_left--);
632 bdat_pop_receive_functions();
634 dkim_save = dkim_collect_input;
635 dkim_collect_input = 0;
638 /* Unless PIPELINING was offered, there should be no next command
639 until after we ack that chunk */
641 if (!f.smtp_in_pipelining_advertised && !check_sync())
643 unsigned n = smtp_inend - smtp_inptr;
646 incomplete_transaction_log(US"sync failure");
647 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
648 "(next input sent too soon: pipelining was not advertised): "
649 "rejected \"%s\" %s next input=\"%s\"%s",
650 smtp_cmd_buffer, host_and_ident(TRUE),
651 string_printing(string_copyn(smtp_inptr, n)),
652 smtp_inend - smtp_inptr > n ? "..." : "");
653 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
654 US"SMTP synchronization error");
655 goto repeat_until_rset;
658 /* If not the last, ack the received chunk. The last response is delayed
659 until after the data ACL decides on it */
661 if (chunking_state == CHUNKING_LAST)
664 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
669 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
670 chunking_state = CHUNKING_OFFERED;
671 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
673 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
674 QUIT, RSET or NOOP but handling them seems obvious */
677 switch(smtp_read_command(TRUE, 1))
680 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
681 US"only BDAT permissible after non-LAST BDAT");
684 switch(smtp_read_command(TRUE, 1))
686 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
687 case EOF_CMD: return EOF;
688 case RSET_CMD: smtp_rset_handler(); return ERR;
689 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
690 US"only RSET accepted now") > 0)
692 goto repeat_until_rset;
696 smtp_quit_handler(&user_msg, &log_msg);
707 smtp_printf("250 OK\r\n", FALSE);
714 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
716 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
717 US"missing size for BDAT command");
720 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
721 ? CHUNKING_LAST : CHUNKING_ACTIVE;
722 chunking_data_left = chunking_datasize;
723 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
724 (int)chunking_state, chunking_data_left);
726 if (chunking_datasize == 0)
727 if (chunking_state == CHUNKING_LAST)
731 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
732 US"zero size for BDAT command");
733 goto repeat_until_rset;
736 bdat_push_receive_functions();
738 dkim_collect_input = dkim_save;
740 break; /* to top of main loop */
747 bdat_getbuf(unsigned * len)
751 if (chunking_data_left <= 0)
752 { *len = 0; return NULL; }
754 if (*len > chunking_data_left) *len = chunking_data_left;
755 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
756 chunking_data_left -= *len;
761 bdat_flush_data(void)
763 while (chunking_data_left)
765 unsigned n = chunking_data_left;
766 if (!bdat_getbuf(&n)) break;
769 bdat_pop_receive_functions();
771 if (chunking_state != CHUNKING_LAST)
773 chunking_state = CHUNKING_OFFERED;
774 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
780 bdat_push_receive_functions(void)
782 /* push the current receive_* function on the "stack", and
783 replace them by bdat_getc(), which in turn will use the lwr_receive_*
784 functions to do the dirty work. */
785 if (lwr_receive_getc == NULL)
787 lwr_receive_getc = receive_getc;
788 lwr_receive_getbuf = receive_getbuf;
789 lwr_receive_ungetc = receive_ungetc;
793 DEBUG(D_receive) debug_printf("chunking double-push receive functions\n");
796 receive_getc = bdat_getc;
797 receive_getbuf = bdat_getbuf;
798 receive_ungetc = bdat_ungetc;
802 bdat_pop_receive_functions(void)
804 if (lwr_receive_getc == NULL)
806 DEBUG(D_receive) debug_printf("chunking double-pop receive functions\n");
809 receive_getc = lwr_receive_getc;
810 receive_getbuf = lwr_receive_getbuf;
811 receive_ungetc = lwr_receive_ungetc;
813 lwr_receive_getc = NULL;
814 lwr_receive_getbuf = NULL;
815 lwr_receive_ungetc = NULL;
818 /*************************************************
819 * SMTP version of ungetc() *
820 *************************************************/
822 /* Puts a character back in the input buffer. Only ever
828 Returns: the character
842 chunking_data_left++;
843 return lwr_receive_ungetc(ch);
848 /*************************************************
849 * SMTP version of feof() *
850 *************************************************/
852 /* Tests for a previous EOF
855 Returns: non-zero if the eof flag is set
867 /*************************************************
868 * SMTP version of ferror() *
869 *************************************************/
871 /* Tests for a previous read error, and returns with errno
872 restored to what it was when the error was detected.
875 Returns: non-zero if the error flag is set
881 errno = smtp_had_error;
882 return smtp_had_error;
887 /*************************************************
888 * Test for characters in the SMTP buffer *
889 *************************************************/
891 /* Used at the end of a message
900 return smtp_inptr < smtp_inend;
905 /*************************************************
906 * Write formatted string to SMTP channel *
907 *************************************************/
909 /* This is a separate function so that we don't have to repeat everything for
910 TLS support or debugging. It is global so that the daemon and the
911 authentication functions can use it. It does not return any error indication,
912 because major problems such as dropped connections won't show up till an output
913 flush for non-TLS connections. The smtp_fflush() function is available for
914 checking that: for convenience, TLS output errors are remembered here so that
915 they are also picked up later by smtp_fflush().
917 This function is exposed to the local_scan API; do not change the signature.
921 more further data expected
922 ... optional arguments
928 smtp_printf(const char *format, BOOL more, ...)
933 smtp_vprintf(format, more, ap);
937 /* This is split off so that verify.c:respond_printf() can, in effect, call
938 smtp_printf(), bearing in mind that in C a vararg function can't directly
939 call another vararg function, only a function which accepts a va_list.
941 This function is exposed to the local_scan API; do not change the signature.
943 /*XXX consider passing caller-info in, for string_vformat-onward */
946 smtp_vprintf(const char *format, BOOL more, va_list ap)
948 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
951 /* Use taint-unchecked routines for writing into big_buffer, trusting
952 that we'll never expand it. */
954 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
955 string_from_gstring(&gs);
959 uschar *msg_copy, *cr, *end;
960 msg_copy = string_copy(gs.s);
961 end = msg_copy + gs.ptr;
962 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
963 memmove(cr, cr + 1, (end--) - cr);
964 debug_printf("SMTP>> %s", msg_copy);
969 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
970 smtp_closedown(US"Unexpected error");
971 exim_exit(EXIT_FAILURE);
974 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
975 have had the same. Note: this code is also present in smtp_respond(). It would
976 be tidier to have it only in one place, but when it was added, it was easier to
977 do it that way, so as not to have to mess with the code for the RCPT command,
978 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
980 if (fl.rcpt_in_progress)
982 if (rcpt_smtp_response == NULL)
983 rcpt_smtp_response = string_copy(big_buffer);
984 else if (fl.rcpt_smtp_response_same &&
985 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
986 fl.rcpt_smtp_response_same = FALSE;
987 fl.rcpt_in_progress = FALSE;
990 /* Now write the string */
994 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
996 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
998 smtp_write_error = -1;
1003 /*************************************************
1004 * Flush SMTP out and check for error *
1005 *************************************************/
1007 /* This function isn't currently used within Exim (it detects errors when it
1008 tries to read the next SMTP input), but is available for use in local_scan().
1009 It flushes the output and checks for errors.
1012 Returns: 0 for no error; -1 after an error
1018 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
1022 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
1024 (fflush(smtp_out) != 0)
1026 smtp_write_error = -1;
1028 return smtp_write_error;
1033 /*************************************************
1034 * SMTP command read timeout *
1035 *************************************************/
1037 /* Signal handler for timing out incoming SMTP commands. This attempts to
1040 Argument: signal number (SIGALRM)
1045 command_timeout_handler(int sig)
1047 had_command_timeout = sig;
1052 /*************************************************
1053 * SIGTERM received *
1054 *************************************************/
1056 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1058 Argument: signal number (SIGTERM)
1063 command_sigterm_handler(int sig)
1065 had_command_sigterm = sig;
1071 #ifdef SUPPORT_PROXY
1072 /*************************************************
1073 * Restore socket timeout to previous value *
1074 *************************************************/
1075 /* If the previous value was successfully retrieved, restore
1076 it before returning control to the non-proxy routines
1078 Arguments: fd - File descriptor for input
1079 get_ok - Successfully retrieved previous values
1080 tvtmp - Time struct with previous values
1081 vslen - Length of time struct
1085 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1088 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1091 /*************************************************
1092 * Check if host is required proxy host *
1093 *************************************************/
1094 /* The function determines if inbound host will be a regular smtp host
1095 or if it is configured that it must use Proxy Protocol. A local
1103 check_proxy_protocol_host()
1107 if ( sender_host_address
1108 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1109 sender_host_address, NULL)) == OK)
1112 debug_printf("Detected proxy protocol configured host\n");
1113 proxy_session = TRUE;
1115 return proxy_session;
1119 /*************************************************
1120 * Read data until newline or end of buffer *
1121 *************************************************/
1122 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1123 read an entire buffer and assume there will be nothing past a proxy protocol
1124 header. Our approach normally is to use stdio, but again that relies upon
1125 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1126 reading _nothing_ before client TLS handshake. So we don't want to use the
1127 usual buffering reads which may read enough to block TLS starting.
1129 So unfortunately we're down to "read one byte at a time, with a syscall each,
1130 and expect a little overhead", for all proxy-opened connections which are v1,
1131 just to handle the TLS-on-connect case. Since SSL functions wrap the
1132 underlying fd, we can't assume that we can feed them any already-read content.
1134 We need to know where to read to, the max capacity, and we'll read until we
1135 get a CR and one more character. Let the caller scream if it's CR+!LF.
1137 Return the amount read.
1141 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1143 uschar *to = base + already;
1149 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1150 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1152 cr = memchr(base, '\r', already);
1155 if ((cr - base) < already - 1)
1157 /* \r and presumed \n already within what we have; probably not
1158 actually proxy protocol, but abort cleanly. */
1161 /* \r is last character read, just need one more. */
1165 while (capacity > 0)
1167 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1179 /* reached end without having room for a final newline, abort */
1184 /*************************************************
1185 * Setup host for proxy protocol *
1186 *************************************************/
1187 /* The function configures the connection based on a header from the
1188 inbound host to use Proxy Protocol. The specification is very exact
1189 so exit with an error if do not find the exact required pieces. This
1190 includes an incorrect number of spaces separating args.
1193 Returns: Boolean success
1197 setup_proxy_protocol_host()
1209 struct { /* TCP/UDP over IPv4, len = 12 */
1215 struct { /* TCP/UDP over IPv6, len = 36 */
1216 uint8_t src_addr[16];
1217 uint8_t dst_addr[16];
1221 struct { /* AF_UNIX sockets, len = 216 */
1222 uschar src_addr[108];
1223 uschar dst_addr[108];
1229 /* Temp variables used in PPv2 address:port parsing */
1231 char tmpip[INET_ADDRSTRLEN];
1232 struct sockaddr_in tmpaddr;
1233 char tmpip6[INET6_ADDRSTRLEN];
1234 struct sockaddr_in6 tmpaddr6;
1236 /* We can't read "all data until end" because while SMTP is
1237 server-speaks-first, the TLS handshake is client-speaks-first, so for
1238 TLS-on-connect ports the proxy protocol header will usually be immediately
1239 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1240 reinject data for reading by those. So instead we first read "enough to be
1241 safely read within the header, and figure out how much more to read".
1242 For v1 we will later read to the end-of-line, for v2 we will read based upon
1245 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1246 data is needed total. For v1, where the line looks like:
1247 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1249 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1250 We seem to support that. So, if we read 14 octets then we can tell if we're
1251 v2 or v1. If we're v1, we can continue reading as normal.
1253 If we're v2, we can't slurp up the entire header. We need the length in the
1254 15th & 16th octets, then to read everything after that.
1256 So to safely handle v1 and v2, with client-sent-first supported correctly,
1257 we have to do a minimum of 3 read calls, not 1. Eww.
1260 #define PROXY_INITIAL_READ 14
1261 #define PROXY_V2_HEADER_SIZE 16
1262 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1263 # error Code bug in sizes of data to read for proxy usage
1268 int fd = fileno(smtp_in);
1269 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1270 uschar * iptype; /* To display debug info */
1272 struct timeval tvtmp;
1273 socklen_t vslen = sizeof(struct timeval);
1276 /* Save current socket timeout values */
1277 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1279 /* Proxy Protocol host must send header within a short time
1280 (default 3 seconds) or it's considered invalid */
1281 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1282 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1283 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1288 /* The inbound host was declared to be a Proxy Protocol host, so
1289 don't do a PEEK into the data, actually slurp up enough to be
1290 "safe". Can't take it all because TLS-on-connect clients follow
1291 immediately with TLS handshake. */
1292 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1294 while (ret == -1 && errno == EINTR);
1299 /* For v2, handle reading the length, and then the rest. */
1300 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1305 /* First get the length fields. */
1308 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1309 } while (retmore == -1 && errno == EINTR);
1314 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1316 /* May 2014: haproxy combined the version and command into one byte to
1317 allow two full bytes for the length field in order to proxy SSL
1318 connections. SSL Proxy is not supported in this version of Exim, but
1319 must still separate values here. */
1323 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1327 /* The v2 header will always be 16 bytes per the spec. */
1328 size = 16 + ntohs(hdr.v2.len);
1329 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1330 size, (int)sizeof(hdr));
1332 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1333 amount that we need. Double-check that the size is not unreasonable, then
1335 if (size > sizeof(hdr))
1337 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1345 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1346 } while (retmore == -1 && errno == EINTR);
1350 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1351 } while (ret < size);
1353 } /* end scope for getting rest of data for v2 */
1355 /* At this point: if PROXYv2, we've read the exact size required for all data;
1356 if PROXYv1 then we've read "less than required for any valid line" and should
1359 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1361 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1365 case 0x01: /* PROXY command */
1368 case 0x11: /* TCPv4 address type */
1370 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1371 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1372 if (!string_is_ip_address(US tmpip, NULL))
1374 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1377 proxy_local_address = sender_host_address;
1378 sender_host_address = string_copy(US tmpip);
1379 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1380 proxy_local_port = sender_host_port;
1381 sender_host_port = tmpport;
1382 /* Save dest ip/port */
1383 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1384 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1385 if (!string_is_ip_address(US tmpip, NULL))
1387 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1390 proxy_external_address = string_copy(US tmpip);
1391 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1392 proxy_external_port = tmpport;
1394 case 0x21: /* TCPv6 address type */
1396 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1397 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1398 if (!string_is_ip_address(US tmpip6, NULL))
1400 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1403 proxy_local_address = sender_host_address;
1404 sender_host_address = string_copy(US tmpip6);
1405 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1406 proxy_local_port = sender_host_port;
1407 sender_host_port = tmpport;
1408 /* Save dest ip/port */
1409 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1410 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1411 if (!string_is_ip_address(US tmpip6, NULL))
1413 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1416 proxy_external_address = string_copy(US tmpip6);
1417 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1418 proxy_external_port = tmpport;
1422 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1426 /* Unsupported protocol, keep local connection address */
1428 case 0x00: /* LOCAL command */
1429 /* Keep local connection address for LOCAL */
1434 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1438 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1442 uschar *sp; /* Utility variables follow */
1447 /* get the rest of the line */
1448 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1453 p = string_copy(hdr.v1.line);
1454 end = memchr(p, '\r', ret - 1);
1456 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1458 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1461 *end = '\0'; /* Terminate the string */
1462 size = end + 2 - p; /* Skip header + CRLF */
1463 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1464 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1465 /* Step through the string looking for the required fields. Ensure
1466 strict adherence to required formatting, exit for any error. */
1468 if (!isspace(*(p++)))
1470 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1473 if (!Ustrncmp(p, CCS"TCP4", 4))
1475 else if (!Ustrncmp(p,CCS"TCP6", 4))
1477 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1479 iptype = US"Unknown";
1484 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1488 p += Ustrlen(iptype);
1489 if (!isspace(*(p++)))
1491 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1494 /* Find the end of the arg */
1495 if ((sp = Ustrchr(p, ' ')) == NULL)
1498 debug_printf("Did not find proxied src %s\n", iptype);
1502 if(!string_is_ip_address(p, NULL))
1505 debug_printf("Proxied src arg is not an %s address\n", iptype);
1508 proxy_local_address = sender_host_address;
1509 sender_host_address = p;
1511 if ((sp = Ustrchr(p, ' ')) == NULL)
1514 debug_printf("Did not find proxy dest %s\n", iptype);
1518 if(!string_is_ip_address(p, NULL))
1521 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1524 proxy_external_address = p;
1526 if ((sp = Ustrchr(p, ' ')) == NULL)
1528 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1532 tmp_port = strtol(CCS p, &endc, 10);
1533 if (*endc || tmp_port == 0)
1536 debug_printf("Proxied src port '%s' not an integer\n", p);
1539 proxy_local_port = sender_host_port;
1540 sender_host_port = tmp_port;
1542 if ((sp = Ustrchr(p, '\0')) == NULL)
1544 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1547 tmp_port = strtol(CCS p, &endc, 10);
1548 if (*endc || tmp_port == 0)
1551 debug_printf("Proxy dest port '%s' not an integer\n", p);
1554 proxy_external_port = tmp_port;
1555 /* Already checked for /r /n above. Good V1 header received. */
1559 /* Wrong protocol */
1560 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1561 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1567 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1568 yield = proxy_session;
1570 /* Don't flush any potential buffer contents. Any input on proxyfail
1571 should cause a synchronization failure */
1574 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1579 sender_host_name = NULL;
1580 (void) host_name_lookup();
1581 host_build_sender_fullhost();
1585 f.proxy_session_failed = TRUE;
1587 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1594 /*************************************************
1595 * Read one command line *
1596 *************************************************/
1598 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1599 There are sites that don't do this, and in any case internal SMTP probably
1600 should check only for LF. Consequently, we check here for LF only. The line
1601 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1602 an unknown command. The command is read into the global smtp_cmd_buffer so that
1603 it is available via $smtp_command.
1605 The character reading routine sets up a timeout for each block actually read
1606 from the input (which may contain more than one command). We set up a special
1607 signal handler that closes down the session on a timeout. Control does not
1608 return when it runs.
1611 check_sync if TRUE, check synchronization rules if global option is TRUE
1612 buffer_lim maximum to buffer in lower layer
1614 Returns: a code identifying the command (enumerated above)
1618 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1622 BOOL hadnull = FALSE;
1624 had_command_timeout = 0;
1625 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1627 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1629 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1631 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1639 smtp_cmd_buffer[ptr++] = c;
1642 receive_linecount++; /* For BSMTP errors */
1643 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1645 /* If hit end of file, return pseudo EOF command. Whether we have a
1646 part-line already read doesn't matter, since this is an error state. */
1648 if (c == EOF) return EOF_CMD;
1650 /* Remove any CR and white space at the end of the line, and terminate the
1653 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1654 smtp_cmd_buffer[ptr] = 0;
1656 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1658 /* NULLs are not allowed in SMTP commands */
1660 if (hadnull) return BADCHAR_CMD;
1662 /* Scan command list and return identity, having set the data pointer
1663 to the start of the actual data characters. Check for SMTP synchronization
1666 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1668 #ifdef SUPPORT_PROXY
1669 /* Only allow QUIT command if Proxy Protocol parsing failed */
1670 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1674 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1675 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1676 || smtp_cmd_buffer[p->len] == 0
1677 || smtp_cmd_buffer[p->len] == ' '
1680 if (smtp_inptr < smtp_inend && /* Outstanding input */
1681 p->cmd < sync_cmd_limit && /* Command should sync */
1682 check_sync && /* Local flag set */
1683 smtp_enforce_sync && /* Global flag set */
1684 sender_host_address != NULL && /* Not local input */
1685 !f.sender_host_notsocket) /* Really is a socket */
1688 /* The variables $smtp_command and $smtp_command_argument point into the
1689 unmodified input buffer. A copy of the latter is taken for actual
1690 processing, so that it can be chopped up into separate parts if necessary,
1691 for example, when processing a MAIL command options such as SIZE that can
1692 follow the sender address. */
1694 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1695 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1696 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1697 smtp_cmd_data = smtp_data_buffer;
1699 /* Count non-mail commands from those hosts that are controlled in this
1700 way. The default is all hosts. We don't waste effort checking the list
1701 until we get a non-mail command, but then cache the result to save checking
1702 again. If there's a DEFER while checking the host, assume it's in the list.
1704 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1705 start of each incoming message by fiddling with the value in the table. */
1707 if (!p->is_mail_cmd)
1709 if (count_nonmail == TRUE_UNSET) count_nonmail =
1710 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1711 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1712 return TOO_MANY_NONMAIL_CMD;
1715 /* If there is data for a command that does not expect it, generate the
1718 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1722 #ifdef SUPPORT_PROXY
1723 /* Only allow QUIT command if Proxy Protocol parsing failed */
1724 if (proxy_session && f.proxy_session_failed)
1725 return PROXY_FAIL_IGNORE_CMD;
1728 /* Enforce synchronization for unknown commands */
1730 if ( smtp_inptr < smtp_inend /* Outstanding input */
1731 && check_sync /* Local flag set */
1732 && smtp_enforce_sync /* Global flag set */
1733 && sender_host_address /* Not local input */
1734 && !f.sender_host_notsocket) /* Really is a socket */
1742 /*************************************************
1743 * Forced closedown of call *
1744 *************************************************/
1746 /* This function is called from log.c when Exim is dying because of a serious
1747 disaster, and also from some other places. If an incoming non-batched SMTP
1748 channel is open, it swallows the rest of the incoming message if in the DATA
1749 phase, sends the reply string, and gives an error to all subsequent commands
1750 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1754 message SMTP reply string to send, excluding the code
1760 smtp_closedown(uschar *message)
1762 if (!smtp_in || smtp_batched_input) return;
1763 receive_swallow_smtp();
1764 smtp_printf("421 %s\r\n", FALSE, message);
1766 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1772 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1777 smtp_printf("250 Reset OK\r\n", FALSE);
1781 smtp_printf("421 %s\r\n", FALSE, message);
1789 /*************************************************
1790 * Set up connection info for logging *
1791 *************************************************/
1793 /* This function is called when logging information about an SMTP connection.
1794 It sets up appropriate source information, depending on the type of connection.
1795 If sender_fullhost is NULL, we are at a very early stage of the connection;
1796 just use the IP address.
1799 Returns: a string describing the connection
1803 smtp_get_connection_info(void)
1805 const uschar * hostname = sender_fullhost
1806 ? sender_fullhost : sender_host_address;
1809 return string_sprintf("SMTP connection from %s", hostname);
1811 if (f.sender_host_unknown || f.sender_host_notsocket)
1812 return string_sprintf("SMTP connection from %s", sender_ident);
1815 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1817 if (LOGGING(incoming_interface) && interface_address)
1818 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1819 interface_address, interface_port);
1821 return string_sprintf("SMTP connection from %s", hostname);
1827 /* Append TLS-related information to a log line
1830 g String under construction: allocated string to extend, or NULL
1832 Returns: Allocated string or NULL
1835 s_tlslog(gstring * g)
1837 if (LOGGING(tls_cipher) && tls_in.cipher)
1839 g = string_append(g, 2, US" X=", tls_in.cipher);
1840 #ifdef EXPERIMENTAL_TLS_RESUME
1841 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1842 g = string_catn(g, US"*", 1);
1845 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1846 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1847 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1848 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1849 if (LOGGING(tls_sni) && tls_in.sni)
1850 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1858 s_connhad_log(gstring * g)
1860 uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1861 ? US" C=..." : US" C=";
1863 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1864 if (smtp_connection_had[i] != SCH_NONE)
1866 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1869 for (int i = 0; i < smtp_ch_index; i++)
1871 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1878 /*************************************************
1879 * Log lack of MAIL if so configured *
1880 *************************************************/
1882 /* This function is called when an SMTP session ends. If the log selector
1883 smtp_no_mail is set, write a log line giving some details of what has happened
1884 in the SMTP session.
1891 smtp_log_no_mail(void)
1896 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1899 if (sender_host_authenticated)
1901 g = string_append(g, 2, US" A=", sender_host_authenticated);
1902 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1909 g = s_connhad_log(g);
1911 if (!(s = string_from_gstring(g))) s = US"";
1913 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1914 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1915 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1919 /* Return list of recent smtp commands */
1924 gstring * list = NULL;
1927 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1928 if (smtp_connection_had[i] != SCH_NONE)
1929 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1931 for (int i = 0; i < smtp_ch_index; i++)
1932 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1934 s = string_from_gstring(list);
1935 return s ? s : US"";
1941 /*************************************************
1942 * Check HELO line and set sender_helo_name *
1943 *************************************************/
1945 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1946 the domain name of the sending host, or an ip literal in square brackets. The
1947 argument is placed in sender_helo_name, which is in malloc store, because it
1948 must persist over multiple incoming messages. If helo_accept_junk is set, this
1949 host is permitted to send any old junk (needed for some broken hosts).
1950 Otherwise, helo_allow_chars can be used for rogue characters in general
1951 (typically people want to let in underscores).
1954 s the data portion of the line (already past any white space)
1956 Returns: TRUE or FALSE
1960 check_helo(uschar *s)
1963 uschar *end = s + Ustrlen(s);
1964 BOOL yield = fl.helo_accept_junk;
1966 /* Discard any previous helo name */
1968 sender_helo_name = NULL;
1970 /* Skip tests if junk is permitted. */
1974 /* Allow the new standard form for IPv6 address literals, namely,
1975 [IPv6:....], and because someone is bound to use it, allow an equivalent
1976 IPv4 form. Allow plain addresses as well. */
1983 if (strncmpic(s, US"[IPv6:", 6) == 0)
1984 yield = (string_is_ip_address(s+6, NULL) == 6);
1985 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1986 yield = (string_is_ip_address(s+6, NULL) == 4);
1988 yield = (string_is_ip_address(s+1, NULL) != 0);
1993 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1994 that have been configured (usually underscore - sigh). */
1997 for (yield = TRUE; *s; s++)
1998 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1999 Ustrchr(helo_allow_chars, *s) == NULL)
2005 /* Save argument if OK */
2007 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
2015 /*************************************************
2016 * Extract SMTP command option *
2017 *************************************************/
2019 /* This function picks the next option setting off the end of smtp_cmd_data. It
2020 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
2021 things that can appear there.
2024 name point this at the name
2025 value point this at the data string
2027 Returns: TRUE if found an option
2031 extract_option(uschar **name, uschar **value)
2035 if (Ustrlen(smtp_cmd_data) <= 0) return FALSE;
2036 v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
2037 while (v > smtp_cmd_data && isspace(*v)) v--;
2040 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
2042 /* Take care to not stop at a space embedded in a quoted local-part */
2045 do v--; while (v > smtp_cmd_data && *v != '"');
2046 if (v <= smtp_cmd_data) return FALSE;
2050 if (v <= smtp_cmd_data) return FALSE;
2055 while (n > smtp_cmd_data && isalpha(n[-1])) n--;
2056 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2057 if (n <= smtp_cmd_data || !isspace(n[-1])) return FALSE;
2074 /*************************************************
2075 * Reset for new message *
2076 *************************************************/
2078 /* This function is called whenever the SMTP session is reset from
2079 within either of the setup functions; also from the daemon loop.
2081 Argument: the stacking pool storage reset point
2086 smtp_reset(void *reset_point)
2088 recipients_list = NULL;
2089 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2090 raw_recipients_count = recipients_count = recipients_list_max = 0;
2091 message_linecount = 0;
2093 acl_added_headers = NULL;
2094 acl_removed_headers = NULL;
2095 f.queue_only_policy = FALSE;
2096 rcpt_smtp_response = NULL;
2097 fl.rcpt_smtp_response_same = TRUE;
2098 fl.rcpt_in_progress = FALSE;
2099 f.deliver_freeze = FALSE; /* Can be set by ACL */
2100 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2101 fake_response = OK; /* Can be set by ACL */
2102 #ifdef WITH_CONTENT_SCAN
2103 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2105 f.submission_mode = FALSE; /* Can be set by ACL */
2106 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2107 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2108 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2109 sending_ip_address = NULL;
2110 return_path = sender_address = NULL;
2111 deliver_localpart_data = deliver_domain_data =
2112 recipient_data = sender_data = NULL; /* Can be set by ACL */
2113 deliver_localpart_parent = deliver_localpart_orig = NULL;
2114 deliver_domain_parent = deliver_domain_orig = NULL;
2115 callout_address = NULL;
2116 submission_name = NULL; /* Can be set by ACL */
2117 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2118 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2119 sender_verified_list = NULL; /* No senders verified */
2120 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2121 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2123 authenticated_sender = NULL;
2124 #ifdef EXPERIMENTAL_BRIGHTMAIL
2126 bmi_verdicts = NULL;
2128 dnslist_domain = dnslist_matched = NULL;
2130 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2131 spf_result_guessed = FALSE;
2133 #ifndef DISABLE_DKIM
2134 dkim_cur_signer = dkim_signers =
2135 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2136 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2137 f.dkim_disable_verify = FALSE;
2138 dkim_collect_input = 0;
2139 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2140 dkim_key_length = 0;
2142 #ifdef SUPPORT_DMARC
2143 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2144 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2145 dmarc_used_domain = NULL;
2147 #ifdef EXPERIMENTAL_ARC
2148 arc_state = arc_state_reason = NULL;
2149 arc_received_instance = 0;
2153 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2154 #ifndef DISABLE_PRDR
2155 prdr_requested = FALSE;
2158 message_smtputf8 = FALSE;
2160 body_linecount = body_zerocount = 0;
2162 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2163 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2164 /* Note that ratelimiters_conn persists across resets. */
2166 /* Reset message ACL variables */
2170 /* The message body variables use malloc store. They may be set if this is
2171 not the first message in an SMTP session and the previous message caused them
2172 to be referenced in an ACL. */
2176 store_free(message_body);
2177 message_body = NULL;
2180 if (message_body_end)
2182 store_free(message_body_end);
2183 message_body_end = NULL;
2186 /* Warning log messages are also saved in malloc store. They are saved to avoid
2187 repetition in the same message, but it seems right to repeat them for different
2190 while (acl_warn_logged)
2192 string_item *this = acl_warn_logged;
2193 acl_warn_logged = acl_warn_logged->next;
2196 store_reset(reset_point);
2197 return store_mark();
2204 /*************************************************
2205 * Initialize for incoming batched SMTP message *
2206 *************************************************/
2208 /* This function is called from smtp_setup_msg() in the case when
2209 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2210 of messages in one file with SMTP commands between them. All errors must be
2211 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2212 relevant. After an error on a sender, or an invalid recipient, the remainder
2213 of the message is skipped. The value of received_protocol is already set.
2216 Returns: > 0 message successfully started (reached DATA)
2217 = 0 QUIT read or end of file reached
2218 < 0 should not occur
2222 smtp_setup_batch_msg(void)
2225 rmark reset_point = store_mark();
2227 /* Save the line count at the start of each transaction - single commands
2228 like HELO and RSET count as whole transactions. */
2230 bsmtp_transaction_linecount = receive_linecount;
2232 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2234 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2235 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2237 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2238 value. The values are 2 larger than the required yield of the function. */
2243 uschar *recipient = NULL;
2244 int start, end, sender_domain, recipient_domain;
2246 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2248 /* The HELO/EHLO commands set sender_address_helo if they have
2249 valid data; otherwise they are ignored, except that they do
2250 a reset of the state. */
2255 check_helo(smtp_cmd_data);
2259 cancel_cutthrough_connection(TRUE, US"RSET received");
2260 reset_point = smtp_reset(reset_point);
2261 bsmtp_transaction_linecount = receive_linecount;
2265 /* The MAIL FROM command requires an address as an operand. All we
2266 do here is to parse it for syntactic correctness. The form "<>" is
2267 a special case which converts into an empty string. The start/end
2268 pointers in the original are not used further for this address, as
2269 it is the canonical extracted address which is all that is kept. */
2272 smtp_mailcmd_count++; /* Count for no-mail log */
2273 if (sender_address != NULL)
2274 /* The function moan_smtp_batch() does not return. */
2275 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2277 if (smtp_cmd_data[0] == 0)
2278 /* The function moan_smtp_batch() does not return. */
2279 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2281 /* Reset to start of message */
2283 cancel_cutthrough_connection(TRUE, US"MAIL received");
2284 reset_point = smtp_reset(reset_point);
2286 /* Apply SMTP rewrite */
2288 raw_sender = rewrite_existflags & rewrite_smtp
2289 /* deconst ok as smtp_cmd_data was not const */
2290 ? US rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL,
2291 FALSE, US"", global_rewrite_rules)
2294 /* Extract the address; the TRUE flag allows <> as valid */
2297 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2301 /* The function moan_smtp_batch() does not return. */
2302 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2304 sender_address = string_copy(raw_sender);
2306 /* Qualify unqualified sender addresses if permitted to do so. */
2309 && sender_address[0] != 0 && sender_address[0] != '@')
2310 if (f.allow_unqualified_sender)
2312 /* deconst ok as sender_address was not const */
2313 sender_address = US rewrite_address_qualify(sender_address, FALSE);
2314 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2315 "and rewritten\n", raw_sender);
2317 /* The function moan_smtp_batch() does not return. */
2319 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2324 /* The RCPT TO command requires an address as an operand. All we do
2325 here is to parse it for syntactic correctness. There may be any number
2326 of RCPT TO commands, specifying multiple senders. We build them all into
2327 a data structure that is in argc/argv format. The start/end values
2328 given by parse_extract_address are not used, as we keep only the
2329 extracted address. */
2332 if (!sender_address)
2333 /* The function moan_smtp_batch() does not return. */
2334 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2336 if (smtp_cmd_data[0] == 0)
2337 /* The function moan_smtp_batch() does not return. */
2338 moan_smtp_batch(smtp_cmd_buffer,
2339 "501 RCPT TO must have an address operand");
2341 /* Check maximum number allowed */
2343 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2344 /* The function moan_smtp_batch() does not return. */
2345 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2346 recipients_max_reject? "552": "452");
2348 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2349 recipient address */
2351 recipient = rewrite_existflags & rewrite_smtp
2352 /* deconst ok as smtp_cmd_data was not const */
2353 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2354 global_rewrite_rules)
2357 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2358 &recipient_domain, FALSE);
2361 /* The function moan_smtp_batch() does not return. */
2362 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2364 /* If the recipient address is unqualified, qualify it if permitted. Then
2365 add it to the list of recipients. */
2367 if (!recipient_domain)
2368 if (f.allow_unqualified_recipient)
2370 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2372 /* deconst ok as recipient was not const */
2373 recipient = US rewrite_address_qualify(recipient, TRUE);
2375 /* The function moan_smtp_batch() does not return. */
2377 moan_smtp_batch(smtp_cmd_buffer,
2378 "501 recipient address must contain a domain");
2380 receive_add_recipient(recipient, -1);
2384 /* The DATA command is legal only if it follows successful MAIL FROM
2385 and RCPT TO commands. This function is complete when a valid DATA
2386 command is encountered. */
2389 if (!sender_address || recipients_count <= 0)
2390 /* The function moan_smtp_batch() does not return. */
2391 if (!sender_address)
2392 moan_smtp_batch(smtp_cmd_buffer,
2393 "503 MAIL FROM:<sender> command must precede DATA");
2395 moan_smtp_batch(smtp_cmd_buffer,
2396 "503 RCPT TO:<recipient> must precede DATA");
2399 done = 3; /* DATA successfully achieved */
2400 message_ended = END_NOTENDED; /* Indicate in middle of message */
2405 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2412 bsmtp_transaction_linecount = receive_linecount;
2423 /* The function moan_smtp_batch() does not return. */
2424 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2429 /* The function moan_smtp_batch() does not return. */
2430 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2435 /* The function moan_smtp_batch() does not return. */
2436 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2441 return done - 2; /* Convert yield values */
2449 smtp_log_tls_fail(uschar * errstr)
2451 uschar * conn_info = smtp_get_connection_info();
2453 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2454 /* I'd like to get separated H= here, but too hard for now */
2456 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2470 socklen_t len = sizeof(is_fastopen);
2472 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2473 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2475 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2480 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2481 f.tcp_in_fastopen = TRUE;
2484 else DEBUG(D_receive)
2485 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2487 # elif defined(TCP_INFO)
2488 struct tcp_info tinfo;
2489 socklen_t len = sizeof(tinfo);
2491 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2492 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2493 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2496 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2497 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2501 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2504 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2505 f.tcp_in_fastopen = TRUE;
2507 else DEBUG(D_receive)
2508 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2514 /*************************************************
2515 * Start an SMTP session *
2516 *************************************************/
2518 /* This function is called at the start of an SMTP session. Thereafter,
2519 smtp_setup_msg() is called to initiate each separate message. This
2520 function does host-specific testing, and outputs the banner line.
2523 Returns: FALSE if the session can not continue; something has
2524 gone wrong, or the connection to the host is blocked
2528 smtp_start_session(void)
2531 uschar *user_msg, *log_msg;
2536 gettimeofday(&smtp_connection_start, NULL);
2537 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2538 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2541 /* Default values for certain variables */
2543 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2544 smtp_mailcmd_count = 0;
2545 count_nonmail = TRUE_UNSET;
2546 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2547 smtp_delay_mail = smtp_rlm_base;
2548 fl.auth_advertised = FALSE;
2549 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2550 f.pipelining_enable = TRUE;
2551 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2552 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2554 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2555 authentication settings from -oMaa to remain in force. */
2557 if (!host_checking && !f.sender_host_notsocket)
2558 sender_host_auth_pubname = sender_host_authenticated = NULL;
2559 authenticated_by = NULL;
2562 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2563 tls_in.ourcert = tls_in.peercert = NULL;
2565 tls_in.ocsp = OCSP_NOT_REQ;
2566 fl.tls_advertised = FALSE;
2568 fl.dsn_advertised = FALSE;
2570 fl.smtputf8_advertised = FALSE;
2573 /* Reset ACL connection variables */
2577 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2579 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, TRUE);
2581 smtp_cmd_buffer[0] = 0;
2582 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2584 /* For batched input, the protocol setting can be overridden from the
2585 command line by a trusted caller. */
2587 if (smtp_batched_input)
2589 if (!received_protocol) received_protocol = US"local-bsmtp";
2592 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2593 reset later if any of EHLO/AUTH/STARTTLS are received. */
2597 (sender_host_address ? protocols : protocols_local) [pnormal];
2599 /* Set up the buffer for inputting using direct read() calls, and arrange to
2600 call the local functions instead of the standard C ones. Place a NUL at the
2601 end of the buffer to safety-stop C-string reads from it. */
2603 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2604 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2605 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2607 receive_getc = smtp_getc;
2608 receive_getbuf = smtp_getbuf;
2609 receive_get_cache = smtp_get_cache;
2610 receive_ungetc = smtp_ungetc;
2611 receive_feof = smtp_feof;
2612 receive_ferror = smtp_ferror;
2613 receive_smtp_buffered = smtp_buffered;
2614 lwr_receive_getc = NULL;
2615 lwr_receive_getbuf = NULL;
2616 lwr_receive_ungetc = NULL;
2617 smtp_inptr = smtp_inend = smtp_inbuffer;
2618 smtp_had_eof = smtp_had_error = 0;
2620 /* Set up the message size limit; this may be host-specific */
2622 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2623 if (expand_string_message)
2625 if (thismessage_size_limit == -1)
2626 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2627 "%s", expand_string_message);
2629 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2630 "%s", expand_string_message);
2631 smtp_closedown(US"Temporary local problem - please try later");
2635 /* When a message is input locally via the -bs or -bS options, sender_host_
2636 unknown is set unless -oMa was used to force an IP address, in which case it
2637 is checked like a real remote connection. When -bs is used from inetd, this
2638 flag is not set, causing the sending host to be checked. The code that deals
2639 with IP source routing (if configured) is never required for -bs or -bS and
2640 the flag sender_host_notsocket is used to suppress it.
2642 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2643 reserve for certain hosts and/or networks. */
2645 if (!f.sender_host_unknown)
2648 BOOL reserved_host = FALSE;
2650 /* Look up IP options (source routing info) on the socket if this is not an
2651 -oMa "host", and if any are found, log them and drop the connection.
2653 Linux (and others now, see below) is different to everyone else, so there
2654 has to be some conditional compilation here. Versions of Linux before 2.1.15
2655 used a structure whose name was "options". Somebody finally realized that
2656 this name was silly, and it got changed to "ip_options". I use the
2657 newer name here, but there is a fudge in the script that sets up os.h
2658 to define a macro in older Linux systems.
2660 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2661 glibc 2, which has chosen ip_opts for the structure name. This is now
2662 really a glibc thing rather than a Linux thing, so the condition name
2663 has been changed to reflect this. It is relevant also to GNU/Hurd.
2665 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2666 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2667 a special macro defined in the os.h file.
2669 Some DGUX versions on older hardware appear not to support IP options at
2670 all, so there is now a general macro which can be set to cut out this
2673 How to do this properly in IPv6 is not yet known. */
2675 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2677 #ifdef GLIBC_IP_OPTIONS
2678 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2683 #elif defined DARWIN_IP_OPTIONS
2689 if (!host_checking && !f.sender_host_notsocket)
2692 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2693 struct ip_options *ipopt = store_get(optlen, FALSE);
2695 struct ip_opts ipoptblock;
2696 struct ip_opts *ipopt = &ipoptblock;
2697 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2699 struct ipoption ipoptblock;
2700 struct ipoption *ipopt = &ipoptblock;
2701 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2704 /* Occasional genuine failures of getsockopt() have been seen - for
2705 example, "reset by peer". Therefore, just log and give up on this
2706 call, unless the error is ENOPROTOOPT. This error is given by systems
2707 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2708 of writing. So for that error, carry on - we just can't do an IP options
2711 DEBUG(D_receive) debug_printf("checking for IP options\n");
2713 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2716 if (errno != ENOPROTOOPT)
2718 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2719 host_and_ident(FALSE), strerror(errno));
2720 smtp_printf("451 SMTP service not available\r\n", FALSE);
2725 /* Deal with any IP options that are set. On the systems I have looked at,
2726 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2727 more logging data than will fit in big_buffer. Nevertheless, after somebody
2728 questioned this code, I've added in some paranoid checking. */
2730 else if (optlen > 0)
2732 uschar *p = big_buffer;
2733 uschar *pend = big_buffer + big_buffer_size;
2736 struct in_addr addr;
2739 uschar *optstart = US (ipopt->__data);
2741 uschar *optstart = US (ipopt->ip_opts);
2743 uschar *optstart = US (ipopt->ipopt_list);
2746 DEBUG(D_receive) debug_printf("IP options exist\n");
2748 Ustrcpy(p, "IP options on incoming call:");
2751 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2764 if (!string_format(p, pend-p, " %s [@%s",
2765 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2767 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2769 inet_ntoa(ipopt->ip_dst)))
2771 inet_ntoa(ipopt->ipopt_dst)))
2779 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2781 while (optcount-- > 0)
2783 memcpy(&addr, adptr, sizeof(addr));
2784 if (!string_format(p, pend - p - 1, "%s%s",
2785 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2791 adptr += sizeof(struct in_addr);
2799 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2802 for (int i = 0; i < opt[1]; i++)
2803 p += sprintf(CS p, "%2.2x ", opt[i]);
2811 log_write(0, LOG_MAIN, "%s", big_buffer);
2813 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2815 log_write(0, LOG_MAIN|LOG_REJECT,
2816 "connection from %s refused (IP options)", host_and_ident(FALSE));
2818 smtp_printf("554 SMTP service not available\r\n", FALSE);
2822 /* Length of options = 0 => there are no options */
2824 else DEBUG(D_receive) debug_printf("no IP options found\n");
2826 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2828 /* Set keep-alive in socket options. The option is on by default. This
2829 setting is an attempt to get rid of some hanging connections that stick in
2830 read() when the remote end (usually a dialup) goes away. */
2832 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2833 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2835 /* If the current host matches host_lookup, set the name by doing a
2836 reverse lookup. On failure, sender_host_name will be NULL and
2837 host_lookup_failed will be TRUE. This may or may not be serious - optional
2840 if (verify_check_host(&host_lookup) == OK)
2842 (void)host_name_lookup();
2843 host_build_sender_fullhost();
2846 /* Delay this until we have the full name, if it is looked up. */
2848 set_process_info("handling incoming connection from %s",
2849 host_and_ident(FALSE));
2851 /* Expand smtp_receive_timeout, if needed */
2853 if (smtp_receive_timeout_s)
2856 if ( !(exp = expand_string(smtp_receive_timeout_s))
2858 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2860 log_write(0, LOG_MAIN|LOG_PANIC,
2861 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2864 /* Test for explicit connection rejection */
2866 if (verify_check_host(&host_reject_connection) == OK)
2868 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2869 "from %s (host_reject_connection)", host_and_ident(FALSE));
2870 smtp_printf("554 SMTP service not available\r\n", FALSE);
2874 /* Test with TCP Wrappers if so configured. There is a problem in that
2875 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2876 such as disks dying. In these cases, it is desirable to reject with a 4xx
2877 error instead of a 5xx error. There isn't a "right" way to detect such
2878 problems. The following kludge is used: errno is zeroed before calling
2879 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2880 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2883 #ifdef USE_TCP_WRAPPERS
2885 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2886 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2887 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2888 expand_string_message);
2890 if (!hosts_ctl(tcp_wrappers_name,
2891 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2892 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2893 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2895 if (errno == 0 || errno == ENOENT)
2897 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2898 log_write(L_connection_reject,
2899 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2900 "(tcp wrappers)", host_and_ident(FALSE));
2901 smtp_printf("554 SMTP service not available\r\n", FALSE);
2905 int save_errno = errno;
2906 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2907 "errno value %d\n", save_errno);
2908 log_write(L_connection_reject,
2909 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2910 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2911 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2917 /* Check for reserved slots. The value of smtp_accept_count has already been
2918 incremented to include this process. */
2920 if (smtp_accept_max > 0 &&
2921 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2923 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2925 log_write(L_connection_reject,
2926 LOG_MAIN, "temporarily refused connection from %s: not in "
2927 "reserve list: connected=%d max=%d reserve=%d%s",
2928 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2929 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2930 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2931 "please try again later\r\n", FALSE, smtp_active_hostname);
2934 reserved_host = TRUE;
2937 /* If a load level above which only messages from reserved hosts are
2938 accepted is set, check the load. For incoming calls via the daemon, the
2939 check is done in the superior process if there are no reserved hosts, to
2940 save a fork. In all cases, the load average will already be available
2941 in a global variable at this point. */
2943 if (smtp_load_reserve >= 0 &&
2944 load_average > smtp_load_reserve &&
2946 verify_check_host(&smtp_reserve_hosts) != OK)
2948 log_write(L_connection_reject,
2949 LOG_MAIN, "temporarily refused connection from %s: not in "
2950 "reserve list and load average = %.2f", host_and_ident(FALSE),
2951 (double)load_average/1000.0);
2952 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2953 smtp_active_hostname);
2957 /* Determine whether unqualified senders or recipients are permitted
2958 for this host. Unfortunately, we have to do this every time, in order to
2959 set the flags so that they can be inspected when considering qualifying
2960 addresses in the headers. For a site that permits no qualification, this
2961 won't take long, however. */
2963 f.allow_unqualified_sender =
2964 verify_check_host(&sender_unqualified_hosts) == OK;
2966 f.allow_unqualified_recipient =
2967 verify_check_host(&recipient_unqualified_hosts) == OK;
2969 /* Determine whether HELO/EHLO is required for this host. The requirement
2970 can be hard or soft. */
2972 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2973 if (!fl.helo_required)
2974 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2976 /* Determine whether this hosts is permitted to send syntactic junk
2977 after a HELO or EHLO command. */
2979 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2982 /* For batch SMTP input we are now done. */
2984 if (smtp_batched_input) return TRUE;
2986 /* If valid Proxy Protocol source is connecting, set up session.
2987 * Failure will not allow any SMTP function other than QUIT. */
2989 #ifdef SUPPORT_PROXY
2990 proxy_session = FALSE;
2991 f.proxy_session_failed = FALSE;
2992 if (check_proxy_protocol_host())
2993 setup_proxy_protocol_host();
2996 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2997 smtps port for use with older style SSL MTAs. */
3000 if (tls_in.on_connect)
3002 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
3003 return smtp_log_tls_fail(user_msg);
3004 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3008 /* Run the connect ACL if it exists */
3011 if (acl_smtp_connect)
3014 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
3017 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
3022 /* Output the initial message for a two-way SMTP connection. It may contain
3023 newlines, which then cause a multi-line response to be given. */
3025 code = US"220"; /* Default status code */
3026 esc = US""; /* Default extended status code */
3027 esclen = 0; /* Length of esc */
3031 if (!(s = expand_string(smtp_banner)))
3032 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
3033 "failed: %s", smtp_banner, expand_string_message);
3039 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
3043 esclen = codelen - 4;
3047 /* Remove any terminating newlines; might as well remove trailing space too */
3050 while (p > s && isspace(p[-1])) p--;
3053 /* It seems that CC:Mail is braindead, and assumes that the greeting message
3054 is all contained in a single IP packet. The original code wrote out the
3055 greeting using several calls to fprint/fputc, and on busy servers this could
3056 cause it to be split over more than one packet - which caused CC:Mail to fall
3057 over when it got the second part of the greeting after sending its first
3058 command. Sigh. To try to avoid this, build the complete greeting message
3059 first, and output it in one fell swoop. This gives a better chance of it
3060 ending up as a single packet. */
3062 ss = string_get(256);
3065 do /* At least once, in case we have an empty string */
3068 uschar *linebreak = Ustrchr(p, '\n');
3069 ss = string_catn(ss, code, 3);
3073 ss = string_catn(ss, US" ", 1);
3077 len = linebreak - p;
3078 ss = string_catn(ss, US"-", 1);
3080 ss = string_catn(ss, esc, esclen);
3081 ss = string_catn(ss, p, len);
3082 ss = string_catn(ss, US"\r\n", 2);
3088 /* Before we write the banner, check that there is no input pending, unless
3089 this synchronisation check is disabled. */
3091 #ifndef DISABLE_PIPE_CONNECT
3092 fl.pipe_connect_acceptable =
3093 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3096 if (fl.pipe_connect_acceptable)
3097 f.smtp_in_early_pipe_used = TRUE;
3103 unsigned n = smtp_inend - smtp_inptr;
3104 if (n > 128) n = 128;
3106 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3107 "synchronization error (input sent without waiting for greeting): "
3108 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3109 string_printing(string_copyn(smtp_inptr, n)));
3110 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3114 /* Now output the banner */
3115 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3118 #ifndef DISABLE_PIPE_CONNECT
3119 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3123 string_from_gstring(ss));
3125 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3126 handshake arrived. If so we must have managed a TFO. */
3129 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3139 /*************************************************
3140 * Handle SMTP syntax and protocol errors *
3141 *************************************************/
3143 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3144 to do so. Then transmit the error response. The return value depends on the
3145 number of syntax and protocol errors in this SMTP session.
3148 type error type, given as a log flag bit
3149 code response code; <= 0 means don't send a response
3150 data data to reflect in the response (can be NULL)
3151 errmess the error message
3153 Returns: -1 limit of syntax/protocol errors NOT exceeded
3154 +1 limit of syntax/protocol errors IS exceeded
3156 These values fit in with the values of the "done" variable in the main
3157 processing loop in smtp_setup_msg(). */
3160 synprot_error(int type, int code, uschar *data, uschar *errmess)
3164 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3165 type == L_smtp_syntax_error ? "syntax" : "protocol",
3166 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3168 if (++synprot_error_count > smtp_max_synprot_errors)
3171 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3172 "syntax or protocol errors (last command was \"%s\", %s)",
3173 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3174 string_from_gstring(s_connhad_log(NULL))
3180 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3181 data ? data : US"", data ? US": " : US"", errmess);
3183 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3192 /*************************************************
3193 * Send SMTP response, possibly multiline *
3194 *************************************************/
3196 /* There are, it seems, broken clients out there that cannot handle multiline
3197 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3198 output nothing for non-final calls, and only the first line for anything else.
3201 code SMTP code, may involve extended status codes
3202 codelen length of smtp code; if > 4 there's an ESC
3203 final FALSE if the last line isn't the final line
3204 msg message text, possibly containing newlines
3210 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3215 if (!final && f.no_multiline_responses) return;
3220 esclen = codelen - 4;
3223 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3224 have had the same. Note: this code is also present in smtp_printf(). It would
3225 be tidier to have it only in one place, but when it was added, it was easier to
3226 do it that way, so as not to have to mess with the code for the RCPT command,
3227 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3229 if (fl.rcpt_in_progress)
3231 if (rcpt_smtp_response == NULL)
3232 rcpt_smtp_response = string_copy(msg);
3233 else if (fl.rcpt_smtp_response_same &&
3234 Ustrcmp(rcpt_smtp_response, msg) != 0)
3235 fl.rcpt_smtp_response_same = FALSE;
3236 fl.rcpt_in_progress = FALSE;
3239 /* Now output the message, splitting it up into multiple lines if necessary.
3240 We only handle pipelining these responses as far as nonfinal/final groups,
3241 not the whole MAIL/RCPT/DATA response set. */
3245 uschar *nl = Ustrchr(msg, '\n');
3248 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3251 else if (nl[1] == 0 || f.no_multiline_responses)
3253 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3254 (int)(nl - msg), msg);
3259 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3261 Uskip_whitespace(&msg);
3269 /*************************************************
3270 * Parse user SMTP message *
3271 *************************************************/
3273 /* This function allows for user messages overriding the response code details
3274 by providing a suitable response code string at the start of the message
3275 user_msg. Check the message for starting with a response code and optionally an
3276 extended status code. If found, check that the first digit is valid, and if so,
3277 change the code pointer and length to use the replacement. An invalid code
3278 causes a panic log; in this case, if the log messages is the same as the user
3279 message, we must also adjust the value of the log message to show the code that
3280 is actually going to be used (the original one).
3282 This function is global because it is called from receive.c as well as within
3285 Note that the code length returned includes the terminating whitespace
3286 character, which is always included in the regex match.
3289 code SMTP code, may involve extended status codes
3290 codelen length of smtp code; if > 4 there's an ESC
3292 log_msg optional log message, to be adjusted with the new SMTP code
3293 check_valid if true, verify the response code
3299 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3305 if (!msg || !*msg) return;
3307 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3308 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3310 if (check_valid && (*msg)[0] != (*code)[0])
3312 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3313 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3314 if (log_msg != NULL && *log_msg == *msg)
3315 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3320 *codelen = ovector[1]; /* Includes final space */
3322 *msg += ovector[1]; /* Chop the code off the message */
3329 /*************************************************
3330 * Handle an ACL failure *
3331 *************************************************/
3333 /* This function is called when acl_check() fails. As well as calls from within
3334 this module, it is called from receive.c for an ACL after DATA. It sorts out
3335 logging the incident, and sends the error response. A message containing
3336 newlines is turned into a multiline SMTP response, but for logging, only the
3339 There's a table of default permanent failure response codes to use in
3340 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3341 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3342 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3343 state, because there are broken clients that try VRFY before RCPT. A 5xx
3344 response should be given only when the address is positively known to be
3345 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3346 no explicit code, but if there is one we let it know best.
3347 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3349 From Exim 4.63, it is possible to override the response code details by
3350 providing a suitable response code string at the start of the message provided
3351 in user_msg. The code's first digit is checked for validity.
3354 where where the ACL was called from
3356 user_msg a message that can be included in an SMTP response
3357 log_msg a message for logging
3359 Returns: 0 in most cases
3360 2 if the failure code was FAIL_DROP, in which case the
3361 SMTP connection should be dropped (this value fits with the
3362 "done" variable in smtp_setup_msg() below)
3366 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3368 BOOL drop = rc == FAIL_DROP;
3372 uschar *sender_info = US"";
3374 #ifdef WITH_CONTENT_SCAN
3375 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3377 where == ACL_WHERE_PREDATA ? US"DATA" :
3378 where == ACL_WHERE_DATA ? US"after DATA" :
3379 #ifndef DISABLE_PRDR
3380 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3383 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3384 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3386 if (drop) rc = FAIL;
3388 /* Set the default SMTP code, and allow a user message to change it. */
3390 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3391 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3392 where != ACL_WHERE_VRFY);
3394 /* We used to have sender_address here; however, there was a bug that was not
3395 updating sender_address after a rewrite during a verify. When this bug was
3396 fixed, sender_address at this point became the rewritten address. I'm not sure
3397 this is what should be logged, so I've changed to logging the unrewritten
3398 address to retain backward compatibility. */
3400 #ifndef WITH_CONTENT_SCAN
3401 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3403 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3406 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3407 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3408 sender_host_authenticated ? US" A=" : US"",
3409 sender_host_authenticated ? sender_host_authenticated : US"",
3410 sender_host_authenticated && authenticated_id ? US":" : US"",
3411 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3415 /* If there's been a sender verification failure with a specific message, and
3416 we have not sent a response about it yet, do so now, as a preliminary line for
3417 failures, but not defers. However, always log it for defer, and log it for fail
3418 unless the sender_verify_fail log selector has been turned off. */
3420 if (sender_verified_failed &&
3421 !testflag(sender_verified_failed, af_sverify_told))
3423 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3424 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3426 setflag(sender_verified_failed, af_sverify_told);
3428 if (rc != FAIL || LOGGING(sender_verify_fail))
3429 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3430 host_and_ident(TRUE),
3431 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3432 sender_verified_failed->address,
3433 (sender_verified_failed->message == NULL)? US"" :
3434 string_sprintf(": %s", sender_verified_failed->message));
3436 if (rc == FAIL && sender_verified_failed->user_message)
3437 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3438 testflag(sender_verified_failed, af_verify_pmfail)?
3439 "Postmaster verification failed while checking <%s>\n%s\n"
3440 "Several RFCs state that you are required to have a postmaster\n"
3441 "mailbox for each mail domain. This host does not accept mail\n"
3442 "from domains whose servers reject the postmaster address."
3444 testflag(sender_verified_failed, af_verify_nsfail)?
3445 "Callback setup failed while verifying <%s>\n%s\n"
3446 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3447 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3448 "RFC requirements, and stops you from receiving standard bounce\n"
3449 "messages. This host does not accept mail from domains whose servers\n"
3452 "Verification failed for <%s>\n%s",
3453 sender_verified_failed->address,
3454 sender_verified_failed->user_message));
3456 fl.rcpt_in_progress = save_rcpt_in_progress;
3459 /* Sort out text for logging */
3461 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3462 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3464 /* Send permanent failure response to the command, but the code used isn't
3465 always a 5xx one - see comments at the start of this function. If the original
3466 rc was FAIL_DROP we drop the connection and yield 2. */
3469 smtp_respond(smtp_code, codelen, TRUE,
3470 user_msg ? user_msg : US"Administrative prohibition");
3472 /* Send temporary failure response to the command. Don't give any details,
3473 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3474 verb, and for a header verify when smtp_return_error_details is set.
3476 This conditional logic is all somewhat of a mess because of the odd
3477 interactions between temp_details and return_error_details. One day it should
3478 be re-implemented in a tidier fashion. */
3481 if (f.acl_temp_details && user_msg)
3483 if ( smtp_return_error_details
3484 && sender_verified_failed
3485 && sender_verified_failed->message
3487 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3489 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3492 smtp_respond(smtp_code, codelen, TRUE,
3493 US"Temporary local problem - please try later");
3495 /* Log the incident to the logs that are specified by log_reject_target
3496 (default main, reject). This can be empty to suppress logging of rejections. If
3497 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3498 is closing if required and return 2. */
3500 if (log_reject_target != 0)
3503 gstring * g = s_tlslog(NULL);
3504 uschar * tls = string_from_gstring(g);
3505 if (!tls) tls = US"";
3507 uschar * tls = US"";
3509 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3510 log_reject_target, "%s%s%s %s%srejected %s%s",
3511 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3512 host_and_ident(TRUE),
3515 rc == FAIL ? US"" : US"temporarily ",
3519 if (!drop) return 0;
3521 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3522 smtp_get_connection_info());
3524 /* Run the not-quit ACL, but without any custom messages. This should not be a
3525 problem, because we get here only if some other ACL has issued "drop", and
3526 in that case, *its* custom messages will have been used above. */
3528 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3535 /*************************************************
3536 * Handle SMTP exit when QUIT is not given *
3537 *************************************************/
3539 /* This function provides a logging/statistics hook for when an SMTP connection
3540 is dropped on the floor or the other end goes away. It's a global function
3541 because it's called from receive.c as well as this module. As well as running
3542 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3543 response, either with a custom message from the ACL, or using a default. There
3544 is one case, however, when no message is output - after "drop". In that case,
3545 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3546 passed to this function.
3548 In case things go wrong while processing this function, causing an error that
3549 may re-enter this function, there is a recursion check.
3552 reason What $smtp_notquit_reason will be set to in the ACL;
3553 if NULL, the ACL is not run
3554 code The error code to return as part of the response
3555 defaultrespond The default message if there's no user_msg
3561 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3564 uschar *user_msg = NULL;
3565 uschar *log_msg = NULL;
3567 /* Check for recursive call */
3569 if (fl.smtp_exit_function_called)
3571 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3575 fl.smtp_exit_function_called = TRUE;
3577 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3579 if (acl_smtp_notquit && reason)
3581 smtp_notquit_reason = reason;
3582 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3583 &log_msg)) == ERROR)
3584 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3588 /* If the connection was dropped, we certainly are no longer talking TLS */
3589 tls_in.active.sock = -1;
3591 /* Write an SMTP response if we are expected to give one. As the default
3592 responses are all internal, they should be reasonable size. */
3594 if (code && defaultrespond)
3597 smtp_respond(code, 3, TRUE, user_msg);
3603 va_start(ap, defaultrespond);
3604 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3606 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3615 /*************************************************
3616 * Verify HELO argument *
3617 *************************************************/
3619 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3620 matched. It is also called from ACL processing if verify = helo is used and
3621 verification was not previously tried (i.e. helo_try_verify_hosts was not
3622 matched). The result of its processing is to set helo_verified and
3623 helo_verify_failed. These variables should both be FALSE for this function to
3626 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3627 for IPv6 ::ffff: literals.
3630 Returns: TRUE if testing was completed;
3631 FALSE on a temporary failure
3635 smtp_verify_helo(void)
3639 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3642 if (sender_helo_name == NULL)
3644 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3647 /* Deal with the case of -bs without an IP address */
3649 else if (sender_host_address == NULL)
3651 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3652 f.helo_verified = TRUE;
3655 /* Deal with the more common case when there is a sending IP address */
3657 else if (sender_helo_name[0] == '[')
3659 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3660 Ustrlen(sender_host_address)) == 0;
3663 if (!f.helo_verified)
3665 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3666 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3667 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3672 { if (f.helo_verified) debug_printf("matched host address\n"); }
3675 /* Do a reverse lookup if one hasn't already given a positive or negative
3676 response. If that fails, or the name doesn't match, try checking with a forward
3681 if (sender_host_name == NULL && !host_lookup_failed)
3682 yield = host_name_lookup() != DEFER;
3684 /* If a host name is known, check it and all its aliases. */
3686 if (sender_host_name)
3687 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3689 sender_helo_dnssec = sender_host_dnssec;
3690 HDEBUG(D_receive) debug_printf("matched host name\n");
3694 uschar **aliases = sender_host_aliases;
3696 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3698 sender_helo_dnssec = sender_host_dnssec;
3702 HDEBUG(D_receive) if (f.helo_verified)
3703 debug_printf("matched alias %s\n", *(--aliases));
3706 /* Final attempt: try a forward lookup of the helo name */
3708 if (!f.helo_verified)
3712 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3714 {.request = US"*", .require = US""};
3716 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3718 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3719 NULL, NULL, NULL, &d, NULL, NULL);
3720 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3721 for (host_item * hh = &h; hh; hh = hh->next)
3722 if (Ustrcmp(hh->address, sender_host_address) == 0)
3724 f.helo_verified = TRUE;
3725 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3727 debug_printf("IP address for %s matches calling address\n"
3728 "Forward DNS security status: %sverified\n",
3729 sender_helo_name, sender_helo_dnssec ? "" : "un");
3735 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3742 /*************************************************
3743 * Send user response message *
3744 *************************************************/
3746 /* This function is passed a default response code and a user message. It calls
3747 smtp_message_code() to check and possibly modify the response code, and then
3748 calls smtp_respond() to transmit the response. I put this into a function
3749 just to avoid a lot of repetition.
3752 code the response code
3753 user_msg the user message
3759 smtp_user_msg(uschar *code, uschar *user_msg)
3762 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3763 smtp_respond(code, len, TRUE, user_msg);
3769 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3771 const uschar *set_id = NULL;
3774 /* Run the checking code, passing the remainder of the command line as
3775 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3776 it as the only set numerical variable. The authenticator may set $auth<n>
3777 and also set other numeric variables. The $auth<n> variables are preferred
3778 nowadays; the numerical variables remain for backwards compatibility.
3780 Afterwards, have a go at expanding the set_id string, even if
3781 authentication failed - for bad passwords it can be useful to log the
3782 userid. On success, require set_id to expand and exist, and put it in
3783 authenticated_id. Save this in permanent store, as the working store gets
3784 reset at HELO, RSET, etc. */
3786 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3788 expand_nlength[0] = 0; /* $0 contains nothing */
3790 rc = (au->info->servercode)(au, smtp_cmd_data);
3791 if (au->set_id) set_id = expand_string(au->set_id);
3792 expand_nmax = -1; /* Reset numeric variables */
3793 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3795 /* The value of authenticated_id is stored in the spool file and printed in
3796 log lines. It must not contain binary zeros or newline characters. In
3797 normal use, it never will, but when playing around or testing, this error
3798 can (did) happen. To guard against this, ensure that the id contains only
3799 printing characters. */
3801 if (set_id) set_id = string_printing(set_id);
3803 /* For the non-OK cases, set up additional logging data if set_id
3807 set_id = set_id && *set_id
3808 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3810 /* Switch on the result */
3815 if (!au->set_id || set_id) /* Complete success */
3817 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3818 sender_host_authenticated = au->name;
3819 sender_host_auth_pubname = au->public_name;
3820 authentication_failed = FALSE;
3821 authenticated_fail_id = NULL; /* Impossible to already be set? */
3824 (sender_host_address ? protocols : protocols_local)
3825 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3826 *s = *ss = US"235 Authentication succeeded";
3827 authenticated_by = au;
3831 /* Authentication succeeded, but we failed to expand the set_id string.
3832 Treat this as a temporary error. */
3834 auth_defer_msg = expand_string_message;
3838 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3839 *s = string_sprintf("435 Unable to authenticate at present%s",
3840 auth_defer_user_msg);
3841 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3842 set_id, auth_defer_msg);
3846 *s = *ss = US"501 Invalid base64 data";
3850 *s = *ss = US"501 Authentication cancelled";
3854 *s = *ss = US"553 Initial data not expected";
3858 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3859 *s = US"535 Incorrect authentication data";
3860 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3864 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3865 *s = US"435 Internal error";
3866 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3867 "check", set_id, rc);
3879 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3882 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3884 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3886 rd = Ustrlen(recipient) + 1;
3887 /* deconst ok as *recipient was not const */
3888 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3891 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3893 log_write(L_smtp_syntax_error,
3894 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3895 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3903 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3906 incomplete_transaction_log(US"QUIT");
3909 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3911 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3916 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_CORK, US &on, sizeof(on));
3920 smtp_respond(US"221", 3, TRUE, *user_msgp);
3922 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3925 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3928 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3929 smtp_get_connection_info());
3934 smtp_rset_handler(void)
3937 incomplete_transaction_log(US"RSET");
3938 smtp_printf("250 Reset OK\r\n", FALSE);
3939 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3944 /*************************************************
3945 * Initialize for SMTP incoming message *
3946 *************************************************/
3948 /* This function conducts the initial dialogue at the start of an incoming SMTP
3949 message, and builds a list of recipients. However, if the incoming message
3950 is part of a batch (-bS option) a separate function is called since it would
3951 be messy having tests splattered about all over this function. This function
3952 therefore handles the case where interaction is occurring. The input and output
3953 files are set up in smtp_in and smtp_out.
3955 The global recipients_list is set to point to a vector of recipient_item
3956 blocks, whose number is given by recipients_count. This is extended by the
3957 receive_add_recipient() function. The global variable sender_address is set to
3958 the sender's address. The yield is +1 if a message has been successfully
3959 started, 0 if a QUIT command was encountered or the connection was refused from
3960 the particular host, or -1 if the connection was lost.
3964 Returns: > 0 message successfully started (reached DATA)
3965 = 0 QUIT read or end of file reached or call refused
3970 smtp_setup_msg(void)
3973 BOOL toomany = FALSE;
3974 BOOL discarded = FALSE;
3975 BOOL last_was_rej_mail = FALSE;
3976 BOOL last_was_rcpt = FALSE;
3977 rmark reset_point = store_mark();
3979 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3981 /* Reset for start of new message. We allow one RSET not to be counted as a
3982 nonmail command, for those MTAs that insist on sending it between every
3983 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3984 TLS between messages (an Exim client may do this if it has messages queued up
3985 for the host). Note: we do NOT reset AUTH at this point. */
3987 reset_point = smtp_reset(reset_point);
3988 message_ended = END_NOTSTARTED;
3990 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3992 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3993 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3994 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3996 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3999 if (lwr_receive_getc != NULL)
4001 /* This should have already happened, but if we've gotten confused,
4002 force a reset here. */
4003 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
4004 bdat_pop_receive_functions();
4007 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
4009 had_command_sigterm = 0;
4010 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
4012 /* Batched SMTP is handled in a different function. */
4014 if (smtp_batched_input) return smtp_setup_batch_msg();
4016 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
4017 value. The values are 2 larger than the required yield of the function. */
4021 const uschar **argv;
4022 uschar *etrn_command;
4023 uschar *etrn_serialize_key;
4025 uschar *log_msg, *smtp_code;
4026 uschar *user_msg = NULL;
4027 uschar *recipient = NULL;
4028 uschar *hello = NULL;
4030 BOOL was_rej_mail = FALSE;
4031 BOOL was_rcpt = FALSE;
4032 void (*oldsignal)(int);
4034 int start, end, sender_domain, recipient_domain;
4037 uschar *orcpt = NULL;
4042 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
4043 if ( tls_in.active.sock >= 0
4045 && tls_in.certificate_verified
4046 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
4049 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
4051 for (auth_instance * au = auths; au; au = au->next)
4052 if (strcmpic(US"tls", au->driver_name) == 0)
4055 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4056 &user_msg, &log_msg)) != OK
4058 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4061 smtp_cmd_data = NULL;
4063 if (smtp_in_auth(au, &s, &ss) == OK)
4064 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
4066 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
4074 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
4075 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4076 US &off, sizeof(off));
4079 switch(smtp_read_command(
4080 #ifndef DISABLE_PIPE_CONNECT
4081 !fl.pipe_connect_acceptable,
4085 GETC_BUFFER_UNLIMITED))
4087 /* The AUTH command is not permitted to occur inside a transaction, and may
4088 occur successfully only once per connection. Actually, that isn't quite
4089 true. When TLS is started, all previous information about a connection must
4090 be discarded, so a new AUTH is permitted at that time.
4092 AUTH may only be used when it has been advertised. However, it seems that
4093 there are clients that send AUTH when it hasn't been advertised, some of
4094 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4095 So there's a get-out that allows this to happen.
4097 AUTH is initially labelled as a "nonmail command" so that one occurrence
4098 doesn't get counted. We change the label here so that multiple failing
4099 AUTHS will eventually hit the nonmail threshold. */
4103 authentication_failed = TRUE;
4104 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4106 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4108 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4109 US"AUTH command used when not advertised");
4112 if (sender_host_authenticated)
4114 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4115 US"already authenticated");
4120 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4121 US"not permitted in mail transaction");
4128 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4129 &user_msg, &log_msg)) != OK
4132 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4136 /* Find the name of the requested authentication mechanism. */
4139 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
4141 if (!isalnum(c) && c != '-' && c != '_')
4143 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4144 US"invalid character in authentication mechanism name");
4150 /* If not at the end of the line, we must be at white space. Terminate the
4151 name and move the pointer on to any data that may be present. */
4153 if (*smtp_cmd_data != 0)
4155 *smtp_cmd_data++ = 0;
4156 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4159 /* Search for an authentication mechanism which is configured for use
4160 as a server and which has been advertised (unless, sigh, allow_auth_
4161 unadvertised is set). */
4165 for (au = auths; au; au = au->next)
4166 if (strcmpic(s, au->public_name) == 0 && au->server &&
4167 (au->advertised || f.allow_auth_unadvertised))
4172 c = smtp_in_auth(au, &s, &ss);
4174 smtp_printf("%s\r\n", FALSE, s);
4176 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4177 au->name, host_and_ident(FALSE), ss);
4180 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4181 string_sprintf("%s authentication mechanism not supported", s));
4184 break; /* AUTH_CMD */
4186 /* The HELO/EHLO commands are permitted to appear in the middle of a
4187 session as well as at the beginning. They have the effect of a reset in
4188 addition to their other functions. Their absence at the start cannot be
4189 taken to be an error.
4193 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4194 or 502 failure replies MUST be returned as appropriate. The SMTP
4195 server MUST stay in the same state after transmitting these replies
4196 that it was in before the EHLO was received.
4198 Therefore, we do not do the reset until after checking the command for
4199 acceptability. This change was made for Exim release 4.11. Previously
4200 it did the reset first. */
4213 HELO_EHLO: /* Common code for HELO and EHLO */
4214 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4215 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4217 /* Reject the HELO if its argument was invalid or non-existent. A
4218 successful check causes the argument to be saved in malloc store. */
4220 if (!check_helo(smtp_cmd_data))
4222 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4224 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4225 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4226 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4227 string_printing(smtp_cmd_argument));
4229 if (++synprot_error_count > smtp_max_synprot_errors)
4231 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4232 "syntax or protocol errors (last command was \"%s\", %s)",
4233 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4234 string_from_gstring(s_connhad_log(NULL))
4242 /* If sender_host_unknown is true, we have got here via the -bs interface,
4243 not called from inetd. Otherwise, we are running an IP connection and the
4244 host address will be set. If the helo name is the primary name of this
4245 host and we haven't done a reverse lookup, force one now. If helo_required
4246 is set, ensure that the HELO name matches the actual host. If helo_verify
4247 is set, do the same check, but softly. */
4249 if (!f.sender_host_unknown)
4251 BOOL old_helo_verified = f.helo_verified;
4252 uschar *p = smtp_cmd_data;
4254 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4257 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4258 because otherwise the log can be confusing. */
4260 if ( !sender_host_name
4261 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4262 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4263 (void)host_name_lookup();
4265 /* Rebuild the fullhost info to include the HELO name (and the real name
4266 if it was looked up.) */
4268 host_build_sender_fullhost(); /* Rebuild */
4269 set_process_info("handling%s incoming connection from %s",
4270 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4272 /* Verify if configured. This doesn't give much security, but it does
4273 make some people happy to be able to do it. If helo_required is set,
4274 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4275 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4276 now obsolescent, since the verification can now be requested selectively
4279 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4280 if (fl.helo_required || fl.helo_verify)
4282 BOOL tempfail = !smtp_verify_helo();
4283 if (!f.helo_verified)
4285 if (fl.helo_required)
4287 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4288 tempfail? 451 : 550, hello);
4289 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4290 tempfail? "temporarily " : "",
4291 hello, sender_helo_name, host_and_ident(FALSE));
4292 f.helo_verified = old_helo_verified;
4293 break; /* End of HELO/EHLO processing */
4295 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4296 "helo_try_verify_hosts\n", hello);
4302 /* set up SPF context */
4303 spf_conn_init(sender_helo_name, sender_host_address);
4306 /* Apply an ACL check if one is defined; afterwards, recheck
4307 synchronization in case the client started sending in a delay. */
4310 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4311 &user_msg, &log_msg)) != OK)
4313 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4314 sender_helo_name = NULL;
4315 host_build_sender_fullhost(); /* Rebuild */
4318 #ifndef DISABLE_PIPE_CONNECT
4319 else if (!fl.pipe_connect_acceptable && !check_sync())
4321 else if (!check_sync())
4325 /* Generate an OK reply. The default string includes the ident if present,
4326 and also the IP address if present. Reflecting back the ident is intended
4327 as a deterrent to mail forgers. For maximum efficiency, and also because
4328 some broken systems expect each response to be in a single packet, arrange
4329 that the entire reply is sent in one write(). */
4331 fl.auth_advertised = FALSE;
4332 f.smtp_in_pipelining_advertised = FALSE;
4334 fl.tls_advertised = FALSE;
4336 fl.dsn_advertised = FALSE;
4338 fl.smtputf8_advertised = FALSE;
4341 smtp_code = US"250 "; /* Default response code plus space*/
4344 /* sender_host_name below will be tainted, so save on copy when we hit it */
4345 g = string_get_tainted(24, TRUE);
4346 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4348 smtp_active_hostname,
4349 sender_ident ? sender_ident : US"",
4350 sender_ident ? US" at " : US"",
4351 sender_host_name ? sender_host_name : sender_helo_name);
4353 if (sender_host_address)
4354 g = string_fmt_append(g, " [%s]", sender_host_address);
4357 /* A user-supplied EHLO greeting may not contain more than one line. Note
4358 that the code returned by smtp_message_code() includes the terminating
4359 whitespace character. */
4365 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4366 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4367 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4369 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4370 "newlines: message truncated: %s", string_printing(s));
4373 g = string_cat(NULL, s);
4376 g = string_catn(g, US"\r\n", 2);
4378 /* If we received EHLO, we must create a multiline response which includes
4379 the functions supported. */
4385 /* I'm not entirely happy with this, as an MTA is supposed to check
4386 that it has enough room to accept a message of maximum size before
4387 it sends this. However, there seems little point in not sending it.
4388 The actual size check happens later at MAIL FROM time. By postponing it
4389 till then, VRFY and EXPN can be used after EHLO when space is short. */
4391 if (thismessage_size_limit > 0)
4392 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4393 thismessage_size_limit);
4396 g = string_catn(g, smtp_code, 3);
4397 g = string_catn(g, US"-SIZE\r\n", 7);
4400 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4401 clean; if it has an 8-bit character in its hand, it just sends it. It
4402 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4403 However, some users want this option simply in order to stop MUAs
4404 mangling messages that contain top-bit-set characters. It is therefore
4405 provided as an option. */
4407 if (accept_8bitmime)
4409 g = string_catn(g, smtp_code, 3);
4410 g = string_catn(g, US"-8BITMIME\r\n", 11);
4413 /* Advertise DSN support if configured to do so. */
4414 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4416 g = string_catn(g, smtp_code, 3);
4417 g = string_catn(g, US"-DSN\r\n", 6);
4418 fl.dsn_advertised = TRUE;
4421 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4422 permitted to issue them; a check is made when any host actually tries. */
4426 g = string_catn(g, smtp_code, 3);
4427 g = string_catn(g, US"-ETRN\r\n", 7);
4431 g = string_catn(g, smtp_code, 3);
4432 g = string_catn(g, US"-VRFY\r\n", 7);
4436 g = string_catn(g, smtp_code, 3);
4437 g = string_catn(g, US"-EXPN\r\n", 7);
4440 /* Exim is quite happy with pipelining, so let the other end know that
4441 it is safe to use it, unless advertising is disabled. */
4443 if ( f.pipelining_enable
4444 && verify_check_host(&pipelining_advertise_hosts) == OK)
4446 g = string_catn(g, smtp_code, 3);
4447 g = string_catn(g, US"-PIPELINING\r\n", 13);
4448 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4449 f.smtp_in_pipelining_advertised = TRUE;
4451 #ifndef DISABLE_PIPE_CONNECT
4452 if (fl.pipe_connect_acceptable)
4454 f.smtp_in_early_pipe_advertised = TRUE;
4455 g = string_catn(g, smtp_code, 3);
4456 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4462 /* If any server authentication mechanisms are configured, advertise
4463 them if the current host is in auth_advertise_hosts. The problem with
4464 advertising always is that some clients then require users to
4465 authenticate (and aren't configurable otherwise) even though it may not
4466 be necessary (e.g. if the host is in host_accept_relay).
4468 RFC 2222 states that SASL mechanism names contain only upper case
4469 letters, so output the names in upper case, though we actually recognize
4470 them in either case in the AUTH command. */
4474 && !sender_host_authenticated
4476 && verify_check_host(&auth_advertise_hosts) == OK
4480 for (auth_instance * au = auths; au; au = au->next)
4482 au->advertised = FALSE;
4485 DEBUG(D_auth+D_expand) debug_printf_indent(
4486 "Evaluating advertise_condition for %s %s athenticator\n",
4487 au->name, au->public_name);
4488 if ( !au->advertise_condition
4489 || expand_check_condition(au->advertise_condition, au->name,
4496 g = string_catn(g, smtp_code, 3);
4497 g = string_catn(g, US"-AUTH", 5);
4499 fl.auth_advertised = TRUE;
4502 g = string_catn(g, US" ", 1);
4503 g = string_cat (g, au->public_name);
4504 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4505 au->advertised = TRUE;
4510 if (!first) g = string_catn(g, US"\r\n", 2);
4513 /* RFC 3030 CHUNKING */
4515 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4517 g = string_catn(g, smtp_code, 3);
4518 g = string_catn(g, US"-CHUNKING\r\n", 11);
4519 f.chunking_offered = TRUE;
4520 chunking_state = CHUNKING_OFFERED;
4523 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4524 if it has been included in the binary, and the host matches
4525 tls_advertise_hosts. We must *not* advertise if we are already in a
4526 secure connection. */
4529 if (tls_in.active.sock < 0 &&
4530 verify_check_host(&tls_advertise_hosts) != FAIL)
4532 g = string_catn(g, smtp_code, 3);
4533 g = string_catn(g, US"-STARTTLS\r\n", 11);
4534 fl.tls_advertised = TRUE;
4538 #ifndef DISABLE_PRDR
4539 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4542 g = string_catn(g, smtp_code, 3);
4543 g = string_catn(g, US"-PRDR\r\n", 7);
4548 if ( accept_8bitmime
4549 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4551 g = string_catn(g, smtp_code, 3);
4552 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4553 fl.smtputf8_advertised = TRUE;
4557 /* Finish off the multiline reply with one that is always available. */
4559 g = string_catn(g, smtp_code, 3);
4560 g = string_catn(g, US" HELP\r\n", 7);
4563 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4567 if (tls_in.active.sock >= 0)
4568 (void)tls_write(NULL, g->s, g->ptr,
4569 # ifndef DISABLE_PIPE_CONNECT
4570 fl.pipe_connect_acceptable && pipeline_connect_sends());
4578 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4584 (void) string_from_gstring(g);
4585 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4586 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4587 debug_printf("SMTP>> %s", g->s);
4589 fl.helo_seen = TRUE;
4591 /* Reset the protocol and the state, abandoning any previous message. */
4593 (sender_host_address ? protocols : protocols_local)
4595 ? pextend + (sender_host_authenticated ? pauthed : 0)
4597 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4599 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4600 reset_point = smtp_reset(reset_point);
4602 break; /* HELO/EHLO */
4605 /* The MAIL command requires an address as an operand. All we do
4606 here is to parse it for syntactic correctness. The form "<>" is
4607 a special case which converts into an empty string. The start/end
4608 pointers in the original are not used further for this address, as
4609 it is the canonical extracted address which is all that is kept. */
4613 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4614 was_rej_mail = TRUE; /* Reset if accepted */
4615 env_mail_type_t * mail_args; /* Sanity check & validate args */
4617 if (fl.helo_required && !fl.helo_seen)
4619 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4620 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4621 "HELO/EHLO given", host_and_ident(FALSE));
4627 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4628 US"sender already given");
4632 if (!*smtp_cmd_data)
4634 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4635 US"MAIL must have an address operand");
4639 /* Check to see if the limit for messages per connection would be
4640 exceeded by accepting further messages. */
4642 if (smtp_accept_max_per_connection > 0 &&
4643 smtp_mailcmd_count > smtp_accept_max_per_connection)
4645 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4646 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4647 "messages in one connection", host_and_ident(TRUE));
4651 /* Reset for start of message - even if this is going to fail, we
4652 obviously need to throw away any previous data. */
4654 cancel_cutthrough_connection(TRUE, US"MAIL received");
4655 reset_point = smtp_reset(reset_point);
4657 sender_data = recipient_data = NULL;
4659 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4661 if (fl.esmtp) for(;;)
4663 uschar *name, *value, *end;
4664 unsigned long int size;
4665 BOOL arg_error = FALSE;
4667 if (!extract_option(&name, &value)) break;
4669 for (mail_args = env_mail_type_list;
4670 mail_args->value != ENV_MAIL_OPT_NULL;
4673 if (strcmpic(name, mail_args->name) == 0)
4675 if (mail_args->need_value && strcmpic(value, US"") == 0)
4678 switch(mail_args->value)
4680 /* Handle SIZE= by reading the value. We don't do the check till later,
4681 in order to be able to log the sender address on failure. */
4682 case ENV_MAIL_OPT_SIZE:
4683 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4685 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4687 message_size = (int)size;
4693 /* If this session was initiated with EHLO and accept_8bitmime is set,
4694 Exim will have indicated that it supports the BODY=8BITMIME option. In
4695 fact, it does not support this according to the RFCs, in that it does not
4696 take any special action for forwarding messages containing 8-bit
4697 characters. That is why accept_8bitmime is not the default setting, but
4698 some sites want the action that is provided. We recognize both "8BITMIME"
4699 and "7BIT" as body types, but take no action. */
4700 case ENV_MAIL_OPT_BODY:
4701 if (accept_8bitmime) {
4702 if (strcmpic(value, US"8BITMIME") == 0)
4704 else if (strcmpic(value, US"7BIT") == 0)
4709 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4710 US"invalid data for BODY");
4713 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4719 /* Handle the two DSN options, but only if configured to do so (which
4720 will have caused "DSN" to be given in the EHLO response). The code itself
4721 is included only if configured in at build time. */
4723 case ENV_MAIL_OPT_RET:
4724 if (fl.dsn_advertised)
4726 /* Check if RET has already been set */
4729 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4730 US"RET can be specified once only");
4733 dsn_ret = strcmpic(value, US"HDRS") == 0
4735 : strcmpic(value, US"FULL") == 0
4738 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4739 /* Check for invalid invalid value, and exit with error */
4742 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4743 US"Value for RET is invalid");
4748 case ENV_MAIL_OPT_ENVID:
4749 if (fl.dsn_advertised)
4751 /* Check if the dsn envid has been already set */
4754 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4755 US"ENVID can be specified once only");
4758 dsn_envid = string_copy(value);
4759 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4763 /* Handle the AUTH extension. If the value given is not "<>" and either
4764 the ACL says "yes" or there is no ACL but the sending host is
4765 authenticated, we set it up as the authenticated sender. However, if the
4766 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4767 the condition is met. The value of AUTH is an xtext, which means that +,
4768 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4770 case ENV_MAIL_OPT_AUTH:
4771 if (Ustrcmp(value, "<>") != 0)
4776 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4778 /* Put back terminator overrides for error message */
4781 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4782 US"invalid data for AUTH");
4785 if (!acl_smtp_mailauth)
4787 ignore_msg = US"client not authenticated";
4788 rc = sender_host_authenticated ? OK : FAIL;
4792 ignore_msg = US"rejected by ACL";
4793 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4794 &user_msg, &log_msg);
4800 if (authenticated_by == NULL ||
4801 authenticated_by->mail_auth_condition == NULL ||
4802 expand_check_condition(authenticated_by->mail_auth_condition,
4803 authenticated_by->name, US"authenticator"))
4804 break; /* Accept the AUTH */
4806 ignore_msg = US"server_mail_auth_condition failed";
4807 if (authenticated_id != NULL)
4808 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4809 ignore_msg, authenticated_id);
4814 authenticated_sender = NULL;
4815 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4816 value, host_and_ident(TRUE), ignore_msg);
4819 /* Should only get DEFER or ERROR here. Put back terminator
4820 overrides for error message */
4825 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4832 #ifndef DISABLE_PRDR
4833 case ENV_MAIL_OPT_PRDR:
4835 prdr_requested = TRUE;
4840 case ENV_MAIL_OPT_UTF8:
4841 if (!fl.smtputf8_advertised)
4843 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4844 US"SMTPUTF8 used when not advertised");
4848 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4849 message_smtputf8 = allow_utf8_domains = TRUE;
4850 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4852 int old_pool = store_pool;
4853 store_pool = POOL_PERM;
4854 received_protocol = string_sprintf("utf8%s", received_protocol);
4855 store_pool = old_pool;
4860 /* No valid option. Stick back the terminator characters and break
4861 the loop. Do the name-terminator second as extract_option sets
4862 value==name when it found no equal-sign.
4863 An error for a malformed address will occur. */
4864 case ENV_MAIL_OPT_NULL:
4872 /* Break out of for loop if switch() had bad argument or
4873 when start of the email address is reached */
4874 if (arg_error) break;
4877 /* If we have passed the threshold for rate limiting, apply the current
4878 delay, and update it for next time, provided this is a limited host. */
4880 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4881 verify_check_host(&smtp_ratelimit_hosts) == OK)
4883 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4884 smtp_delay_mail/1000.0);
4885 millisleep((int)smtp_delay_mail);
4886 smtp_delay_mail *= smtp_rlm_factor;
4887 if (smtp_delay_mail > (double)smtp_rlm_limit)
4888 smtp_delay_mail = (double)smtp_rlm_limit;
4891 /* Now extract the address, first applying any SMTP-time rewriting. The
4892 TRUE flag allows "<>" as a sender address. */
4894 raw_sender = rewrite_existflags & rewrite_smtp
4895 /* deconst ok as smtp_cmd_data was not const */
4896 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4897 global_rewrite_rules)
4901 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4906 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4910 sender_address = raw_sender;
4912 /* If there is a configured size limit for mail, check that this message
4913 doesn't exceed it. The check is postponed to this point so that the sender
4916 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4918 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4919 log_write(L_size_reject,
4920 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4921 "message too big: size%s=%d max=%d",
4923 host_and_ident(TRUE),
4924 (message_size == INT_MAX)? ">" : "",
4926 thismessage_size_limit);
4927 sender_address = NULL;
4931 /* Check there is enough space on the disk unless configured not to.
4932 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4933 plus the current message - i.e. we accept the message only if it won't
4934 reduce the space below the threshold. Add 5000 to the size to allow for
4935 overheads such as the Received: line and storing of recipients, etc.
4936 By putting the check here, even when SIZE is not given, it allow VRFY
4937 and EXPN etc. to be used when space is short. */
4939 if (!receive_check_fs(
4940 smtp_check_spool_space && message_size >= 0
4941 ? message_size + 5000 : 0))
4943 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4944 sender_address = NULL;
4948 /* If sender_address is unqualified, reject it, unless this is a locally
4949 generated message, or the sending host or net is permitted to send
4950 unqualified addresses - typically local machines behaving as MUAs -
4951 in which case just qualify the address. The flag is set above at the start
4952 of the SMTP connection. */
4954 if (!sender_domain && *sender_address)
4955 if (f.allow_unqualified_sender)
4957 sender_domain = Ustrlen(sender_address) + 1;
4958 /* deconst ok as sender_address was not const */
4959 sender_address = US rewrite_address_qualify(sender_address, FALSE);
4960 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4965 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4967 log_write(L_smtp_syntax_error,
4968 LOG_MAIN|LOG_REJECT,
4969 "unqualified sender rejected: <%s> %s%s",
4971 host_and_ident(TRUE),
4973 sender_address = NULL;
4977 /* Apply an ACL check if one is defined, before responding. Afterwards,
4978 when pipelining is not advertised, do another sync check in case the ACL
4979 delayed and the client started sending in the meantime. */
4983 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4984 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4990 if (rc == OK || rc == DISCARD)
4992 BOOL more = pipeline_response();
4995 smtp_printf("%s%s%s", more, US"250 OK",
4996 #ifndef DISABLE_PRDR
4997 prdr_requested ? US", PRDR Requested" : US"",
5004 #ifndef DISABLE_PRDR
5006 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
5008 smtp_user_msg(US"250", user_msg);
5010 smtp_delay_rcpt = smtp_rlr_base;
5011 f.recipients_discarded = (rc == DISCARD);
5012 was_rej_mail = FALSE;
5016 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
5017 sender_address = NULL;
5022 /* The RCPT command requires an address as an operand. There may be any
5023 number of RCPT commands, specifying multiple recipients. We build them all
5024 into a data structure. The start/end values given by parse_extract_address
5025 are not used, as we keep only the extracted address. */
5029 /* We got really to many recipients. A check against configured
5030 limits is done later */
5031 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
5032 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
5034 was_rcpt = fl.rcpt_in_progress = TRUE;
5036 /* There must be a sender address; if the sender was rejected and
5037 pipelining was advertised, we assume the client was pipelining, and do not
5038 count this as a protocol error. Reset was_rej_mail so that further RCPTs
5039 get the same treatment. */
5041 if (sender_address == NULL)
5043 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
5045 smtp_printf("503 sender not yet given\r\n", FALSE);
5046 was_rej_mail = TRUE;
5050 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5051 US"sender not yet given");
5052 was_rcpt = FALSE; /* Not a valid RCPT */
5058 /* Check for an operand */
5060 if (smtp_cmd_data[0] == 0)
5062 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5063 US"RCPT must have an address operand");
5068 /* Set the DSN flags orcpt and dsn_flags from the session*/
5072 if (fl.esmtp) for(;;)
5074 uschar *name, *value;
5076 if (!extract_option(&name, &value))
5079 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5081 /* Check whether orcpt has been already set */
5084 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5085 US"ORCPT can be specified once only");
5088 orcpt = string_copy(value);
5089 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5092 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5094 /* Check if the notify flags have been already set */
5097 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5098 US"NOTIFY can be specified once only");
5101 if (strcmpic(value, US"NEVER") == 0)
5102 dsn_flags |= rf_notify_never;
5109 while (*pp != 0 && *pp != ',') pp++;
5110 if (*pp == ',') *pp++ = 0;
5111 if (strcmpic(p, US"SUCCESS") == 0)
5113 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5114 dsn_flags |= rf_notify_success;
5116 else if (strcmpic(p, US"FAILURE") == 0)
5118 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5119 dsn_flags |= rf_notify_failure;
5121 else if (strcmpic(p, US"DELAY") == 0)
5123 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5124 dsn_flags |= rf_notify_delay;
5128 /* Catch any strange values */
5129 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5130 US"Invalid value for NOTIFY parameter");
5135 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5139 /* Unknown option. Stick back the terminator characters and break
5140 the loop. An error for a malformed address will occur. */
5144 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5151 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5152 as a recipient address */
5154 recipient = rewrite_existflags & rewrite_smtp
5155 /* deconst ok as smtp_cmd_data was not const */
5156 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5157 global_rewrite_rules)
5160 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5161 &recipient_domain, FALSE)))
5163 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5168 /* If the recipient address is unqualified, reject it, unless this is a
5169 locally generated message. However, unqualified addresses are permitted
5170 from a configured list of hosts and nets - typically when behaving as
5171 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5172 really. The flag is set at the start of the SMTP connection.
5174 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5175 assumed this meant "reserved local part", but the revision of RFC 821 and
5176 friends now makes it absolutely clear that it means *mailbox*. Consequently
5177 we must always qualify this address, regardless. */
5179 if (!recipient_domain)
5180 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5187 /* Check maximum allowed */
5189 if (rcpt_count+1 < 0 || rcpt_count > recipients_max && recipients_max > 0)
5191 if (recipients_max_reject)
5194 smtp_printf("552 too many recipients\r\n", FALSE);
5196 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5197 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5202 smtp_printf("452 too many recipients\r\n", FALSE);
5204 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5205 "temporarily rejected: sender=<%s> %s", sender_address,
5206 host_and_ident(TRUE));
5213 /* If we have passed the threshold for rate limiting, apply the current
5214 delay, and update it for next time, provided this is a limited host. */
5216 if (rcpt_count > smtp_rlr_threshold &&
5217 verify_check_host(&smtp_ratelimit_hosts) == OK)
5219 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5220 smtp_delay_rcpt/1000.0);
5221 millisleep((int)smtp_delay_rcpt);
5222 smtp_delay_rcpt *= smtp_rlr_factor;
5223 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5224 smtp_delay_rcpt = (double)smtp_rlr_limit;
5227 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5228 for them. Otherwise, check the access control list for this recipient. As
5229 there may be a delay in this, re-check for a synchronization error
5230 afterwards, unless pipelining was advertised. */
5232 if (f.recipients_discarded)
5235 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5237 && !f.smtp_in_pipelining_advertised && !check_sync())
5240 /* The ACL was happy */
5244 BOOL more = pipeline_response();
5247 smtp_user_msg(US"250", user_msg);
5249 smtp_printf("250 Accepted\r\n", more);
5250 receive_add_recipient(recipient, -1);
5252 /* Set the dsn flags in the recipients_list */
5253 recipients_list[recipients_count-1].orcpt = orcpt;
5254 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5256 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5257 recipients_list[recipients_count-1].orcpt,
5258 recipients_list[recipients_count-1].dsn_flags); */
5261 /* The recipient was discarded */
5263 else if (rc == DISCARD)
5266 smtp_user_msg(US"250", user_msg);
5268 smtp_printf("250 Accepted\r\n", FALSE);
5271 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5272 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5273 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5274 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5275 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5278 /* Either the ACL failed the address, or it was deferred. */
5282 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5283 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5288 /* The DATA command is legal only if it follows successful MAIL FROM
5289 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5290 not counted as a protocol error if it follows RCPT (which must have been
5291 rejected if there are no recipients.) This function is complete when a
5292 valid DATA command is encountered.
5294 Note concerning the code used: RFC 2821 says this:
5296 - If there was no MAIL, or no RCPT, command, or all such commands
5297 were rejected, the server MAY return a "command out of sequence"
5298 (503) or "no valid recipients" (554) reply in response to the
5301 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5302 because it is the same whether pipelining is in use or not.
5304 If all the RCPT commands that precede DATA provoked the same error message
5305 (often indicating some kind of system error), it is helpful to include it
5306 with the DATA rejection (an idea suggested by Tony Finch). */
5313 if (chunking_state != CHUNKING_OFFERED)
5315 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5316 US"BDAT command used when CHUNKING not advertised");
5320 /* grab size, endmarker */
5322 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5324 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5325 US"missing size for BDAT command");
5328 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5329 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5330 chunking_data_left = chunking_datasize;
5331 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5332 (int)chunking_state, chunking_data_left);
5334 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
5343 f.bdat_readers_wanted = FALSE;
5345 DATA_BDAT: /* Common code for DATA and BDAT */
5346 #ifndef DISABLE_PIPE_CONNECT
5347 fl.pipe_connect_acceptable = FALSE;
5349 if (!discarded && recipients_count <= 0)
5351 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5353 uschar *code = US"503";
5354 int len = Ustrlen(rcpt_smtp_response);
5355 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5357 /* Responses from smtp_printf() will have \r\n on the end */
5358 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5359 rcpt_smtp_response[len-2] = 0;
5360 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5362 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5363 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5364 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5366 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5367 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5368 ? US"valid RCPT command must precede DATA"
5369 : US"valid RCPT command must precede BDAT");
5371 if (chunking_state > CHUNKING_OFFERED)
5373 bdat_push_receive_functions();
5379 if (toomany && recipients_max_reject)
5381 sender_address = NULL; /* This will allow a new MAIL without RSET */
5382 sender_address_unrewritten = NULL;
5383 smtp_printf("554 Too many recipients\r\n", FALSE);
5385 if (chunking_state > CHUNKING_OFFERED)
5387 bdat_push_receive_functions();
5393 if (chunking_state > CHUNKING_OFFERED)
5394 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5397 /* If there is an ACL, re-check the synchronization afterwards, since the
5398 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5399 to get the DATA command sent. */
5401 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5405 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5406 f.enable_dollar_recipients = TRUE;
5407 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5409 f.enable_dollar_recipients = FALSE;
5410 if (rc == OK && !check_sync())
5414 { /* Either the ACL failed the address, or it was deferred. */
5415 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5421 smtp_user_msg(US"354", user_msg);
5424 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5427 if (f.bdat_readers_wanted)
5428 bdat_push_receive_functions();
5431 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5432 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5433 US &on, sizeof(on));
5436 message_ended = END_NOTENDED; /* Indicate in middle of data */
5447 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5448 &start, &end, &recipient_domain, FALSE)))
5450 smtp_printf("501 %s\r\n", FALSE, errmess);
5454 if (!recipient_domain)
5455 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5459 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5460 &user_msg, &log_msg)) != OK)
5461 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5465 address_item * addr = deliver_make_addr(address, FALSE);
5467 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5468 -1, -1, NULL, NULL, NULL))
5471 s = string_sprintf("250 <%s> is deliverable", address);
5475 s = (addr->user_message != NULL)?
5476 string_sprintf("451 <%s> %s", address, addr->user_message) :
5477 string_sprintf("451 Cannot resolve <%s> at this time", address);
5481 s = (addr->user_message != NULL)?
5482 string_sprintf("550 <%s> %s", address, addr->user_message) :
5483 string_sprintf("550 <%s> is not deliverable", address);
5484 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5485 smtp_cmd_argument, host_and_ident(TRUE));
5489 smtp_printf("%s\r\n", FALSE, s);
5497 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5499 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5502 BOOL save_log_testing_mode = f.log_testing_mode;
5503 f.address_test_mode = f.log_testing_mode = TRUE;
5504 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5505 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5507 f.address_test_mode = FALSE;
5508 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5517 if (!fl.tls_advertised)
5519 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5520 US"STARTTLS command used when not advertised");
5524 /* Apply an ACL check if one is defined */
5526 if ( acl_smtp_starttls
5527 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5528 &user_msg, &log_msg)) != OK
5531 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5535 /* RFC 2487 is not clear on when this command may be sent, though it
5536 does state that all information previously obtained from the client
5537 must be discarded if a TLS session is started. It seems reasonable to
5538 do an implied RSET when STARTTLS is received. */
5540 incomplete_transaction_log(US"STARTTLS");
5541 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5542 reset_point = smtp_reset(reset_point);
5544 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5546 /* There's an attack where more data is read in past the STARTTLS command
5547 before TLS is negotiated, then assumed to be part of the secure session
5548 when used afterwards; we use segregated input buffers, so are not
5549 vulnerable, but we want to note when it happens and, for sheer paranoia,
5550 ensure that the buffer is "wiped".
5551 Pipelining sync checks will normally have protected us too, unless disabled
5552 by configuration. */
5554 if (receive_smtp_buffered())
5557 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5558 if (tls_in.active.sock < 0)
5559 smtp_inend = smtp_inptr = smtp_inbuffer;
5560 /* and if TLS is already active, tls_server_start() should fail */
5563 /* There is nothing we value in the input buffer and if TLS is successfully
5564 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5565 fresh content into it. The buffer contains arbitrary content from an
5566 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5567 It seems safest to just wipe away the content rather than leave it as a
5568 target to jump to. */
5570 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5572 /* Attempt to start up a TLS session, and if successful, discard all
5573 knowledge that was obtained previously. At least, that's what the RFC says,
5574 and that's what happens by default. However, in order to work round YAEB,
5575 there is an option to remember the esmtp state. Sigh.
5577 We must allow for an extra EHLO command and an extra AUTH command after
5578 STARTTLS that don't add to the nonmail command count. */
5581 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5583 if (!tls_remember_esmtp)
5584 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5585 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5586 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5587 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5588 if (sender_helo_name)
5590 sender_helo_name = NULL;
5591 host_build_sender_fullhost(); /* Rebuild */
5592 set_process_info("handling incoming TLS connection from %s",
5593 host_and_ident(FALSE));
5596 (sender_host_address ? protocols : protocols_local)
5598 ? pextend + (sender_host_authenticated ? pauthed : 0)
5600 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5603 sender_host_auth_pubname = sender_host_authenticated = NULL;
5604 authenticated_id = NULL;
5605 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5606 DEBUG(D_tls) debug_printf("TLS active\n");
5607 break; /* Successful STARTTLS */
5610 (void) smtp_log_tls_fail(s);
5612 /* Some local configuration problem was discovered before actually trying
5613 to do a TLS handshake; give a temporary error. */
5617 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5621 /* Hard failure. Reject everything except QUIT or closed connection. One
5622 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5623 set, but we must still reject all incoming commands. Another is a handshake
5624 failure - and there may some encrypted data still in the pipe to us, which we
5625 see as garbage commands. */
5627 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5628 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5631 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5632 smtp_get_connection_info());
5633 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5637 /* It is perhaps arguable as to which exit ACL should be called here,
5638 but as it is probably a situation that almost never arises, it
5639 probably doesn't matter. We choose to call the real QUIT ACL, which in
5640 some sense is perhaps "right". */
5645 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5646 &log_msg)) == ERROR))
5647 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5650 smtp_respond(US"221", 3, TRUE, user_msg);
5652 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5653 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5654 smtp_get_connection_info());
5659 smtp_printf("554 Security failure\r\n", FALSE);
5662 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5667 /* The ACL for QUIT is provided for gathering statistical information or
5668 similar; it does not affect the response code, but it can supply a custom
5672 smtp_quit_handler(&user_msg, &log_msg);
5678 smtp_rset_handler();
5679 cancel_cutthrough_connection(TRUE, US"RSET received");
5680 reset_point = smtp_reset(reset_point);
5687 smtp_printf("250 OK\r\n", FALSE);
5691 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5692 used, a check will be done for permitted hosts. Show STARTTLS only if not
5693 already in a TLS session and if it would be advertised in the EHLO
5698 smtp_printf("214-Commands supported:\r\n", TRUE);
5702 Ustrcat(buffer, US" AUTH");
5704 if (tls_in.active.sock < 0 &&
5705 verify_check_host(&tls_advertise_hosts) != FAIL)
5706 Ustrcat(buffer, US" STARTTLS");
5708 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5709 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5710 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5711 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5712 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5713 smtp_printf("214%s\r\n", FALSE, buffer);
5719 incomplete_transaction_log(US"connection lost");
5720 smtp_notquit_exit(US"connection-lost", US"421",
5721 US"%s lost input connection", smtp_active_hostname);
5723 /* Don't log by default unless in the middle of a message, as some mailers
5724 just drop the call rather than sending QUIT, and it clutters up the logs.
5727 if (sender_address || recipients_count > 0)
5728 log_write(L_lost_incoming_connection, LOG_MAIN,
5729 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5730 f.sender_host_unknown ? "EOF" : "disconnection",
5731 f.tcp_in_fastopen_logged
5734 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5736 host_and_ident(FALSE), smtp_read_error,
5737 string_timesince(&smtp_connection_start)
5741 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5742 smtp_get_connection_info(),
5743 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5745 string_timesince(&smtp_connection_start)
5756 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5757 US"ETRN is not permitted inside a transaction");
5761 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5762 host_and_ident(FALSE));
5764 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5765 &user_msg, &log_msg)) != OK)
5767 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5771 /* Compute the serialization key for this command. */
5773 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5775 /* If a command has been specified for running as a result of ETRN, we
5776 permit any argument to ETRN. If not, only the # standard form is permitted,
5777 since that is strictly the only kind of ETRN that can be implemented
5778 according to the RFC. */
5780 if (smtp_etrn_command)
5784 etrn_command = smtp_etrn_command;
5785 deliver_domain = smtp_cmd_data;
5786 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5787 US"ETRN processing", &error);
5788 deliver_domain = NULL;
5791 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5793 smtp_printf("458 Internal failure\r\n", FALSE);
5798 /* Else set up to call Exim with the -R option. */
5802 if (*smtp_cmd_data++ != '#')
5804 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5805 US"argument must begin with #");
5808 etrn_command = US"exim -R";
5809 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5810 *queue_name ? 4 : 2,
5811 US"-R", smtp_cmd_data,
5812 US"-MCG", queue_name);
5815 /* If we are host-testing, don't actually do anything. */
5821 debug_printf("ETRN command is: %s\n", etrn_command);
5822 debug_printf("ETRN command execution skipped\n");
5824 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5825 else smtp_user_msg(US"250", user_msg);
5830 /* If ETRN queue runs are to be serialized, check the database to
5831 ensure one isn't already running. */
5833 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5835 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5839 /* Fork a child process and run the command. We don't want to have to
5840 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5841 forking. It should be set that way anyway for external incoming SMTP,
5842 but we save and restore to be tidy. If serialization is required, we
5843 actually run the command in yet another process, so we can wait for it
5844 to complete and then remove the serialization lock. */
5846 oldsignal = signal(SIGCHLD, SIG_IGN);
5848 if ((pid = exim_fork(US"etrn-command")) == 0)
5850 smtp_input = FALSE; /* This process is not associated with the */
5851 (void)fclose(smtp_in); /* SMTP call any more. */
5852 (void)fclose(smtp_out);
5854 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5856 /* If not serializing, do the exec right away. Otherwise, fork down
5857 into another process. */
5859 if ( !smtp_etrn_serialize
5860 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5862 DEBUG(D_exec) debug_print_argv(argv);
5863 exim_nullstd(); /* Ensure std{in,out,err} exist */
5864 execv(CS argv[0], (char *const *)argv);
5865 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5866 etrn_command, strerror(errno));
5867 _exit(EXIT_FAILURE); /* paranoia */
5870 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5871 is, we are in the first subprocess, after forking again. All we can do
5872 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5873 complete, before removing the serialization. */
5876 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5877 "failed: %s", strerror(errno));
5881 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5883 (void)wait(&status);
5884 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5888 enq_end(etrn_serialize_key);
5889 exim_underbar_exit(EXIT_SUCCESS);
5892 /* Back in the top level SMTP process. Check that we started a subprocess
5893 and restore the signal state. */
5897 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5899 smtp_printf("458 Unable to fork process\r\n", FALSE);
5900 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5904 smtp_printf("250 OK\r\n", FALSE);
5906 smtp_user_msg(US"250", user_msg);
5908 signal(SIGCHLD, oldsignal);
5913 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5914 US"unexpected argument data");
5918 /* This currently happens only for NULLs, but could be extended. */
5921 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5922 US"NUL character(s) present (shown as '?')");
5923 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5930 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5931 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5932 c = smtp_inend - smtp_inptr;
5933 if (c > 150) c = 150; /* limit logged amount */
5935 incomplete_transaction_log(US"sync failure");
5936 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5937 "(next input sent too soon: pipelining was%s advertised): "
5938 "rejected \"%s\" %s next input=\"%s\"",
5939 f.smtp_in_pipelining_advertised ? "" : " not",
5940 smtp_cmd_buffer, host_and_ident(TRUE),
5941 string_printing(smtp_inptr));
5942 smtp_notquit_exit(US"synchronization-error", US"554",
5943 US"SMTP synchronization error");
5944 done = 1; /* Pretend eof - drops connection */
5948 case TOO_MANY_NONMAIL_CMD:
5949 s = smtp_cmd_buffer;
5950 while (*s != 0 && !isspace(*s)) s++;
5951 incomplete_transaction_log(US"too many non-mail commands");
5952 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5953 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5954 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5955 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5956 done = 1; /* Pretend eof - drops connection */
5959 #ifdef SUPPORT_PROXY
5960 case PROXY_FAIL_IGNORE_CMD:
5961 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5966 if (unknown_command_count++ >= smtp_max_unknown_commands)
5968 log_write(L_smtp_syntax_error, LOG_MAIN,
5969 "SMTP syntax error in \"%s\" %s %s",
5970 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5971 US"unrecognized command");
5972 incomplete_transaction_log(US"unrecognized command");
5973 smtp_notquit_exit(US"bad-commands", US"500",
5974 US"Too many unrecognized commands");
5976 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5977 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5978 string_printing(smtp_cmd_buffer));
5981 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5982 US"unrecognized command");
5986 /* This label is used by goto's inside loops that want to break out to
5987 the end of the command-processing loop. */
5990 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5991 last_was_rcpt = was_rcpt; /* protocol error handling */
5995 return done - 2; /* Convert yield values */
6001 authres_smtpauth(gstring * g)
6003 if (!sender_host_authenticated)
6006 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
6008 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
6009 g = authenticated_id
6010 ? string_append(g, 2, US") x509.auth=", authenticated_id)
6011 : string_cat(g, US") reason=x509.auth");
6013 g = authenticated_id
6014 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
6015 : string_cat(g, US", no id saved)");
6017 if (authenticated_sender)
6018 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
6026 /* End of smtp_in.c */