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_ungetc = bdat_ungetc;
801 bdat_pop_receive_functions(void)
803 receive_getc = lwr_receive_getc;
804 receive_getbuf = lwr_receive_getbuf;
805 receive_ungetc = lwr_receive_ungetc;
806 lwr_receive_getc = NULL;
807 lwr_receive_getbuf = NULL;
808 lwr_receive_ungetc = NULL;
811 /*************************************************
812 * SMTP version of ungetc() *
813 *************************************************/
815 /* Puts a character back in the input buffer. Only ever
821 Returns: the character
835 chunking_data_left++;
836 return lwr_receive_ungetc(ch);
841 /*************************************************
842 * SMTP version of feof() *
843 *************************************************/
845 /* Tests for a previous EOF
848 Returns: non-zero if the eof flag is set
860 /*************************************************
861 * SMTP version of ferror() *
862 *************************************************/
864 /* Tests for a previous read error, and returns with errno
865 restored to what it was when the error was detected.
868 Returns: non-zero if the error flag is set
874 errno = smtp_had_error;
875 return smtp_had_error;
880 /*************************************************
881 * Test for characters in the SMTP buffer *
882 *************************************************/
884 /* Used at the end of a message
893 return smtp_inptr < smtp_inend;
898 /*************************************************
899 * Write formatted string to SMTP channel *
900 *************************************************/
902 /* This is a separate function so that we don't have to repeat everything for
903 TLS support or debugging. It is global so that the daemon and the
904 authentication functions can use it. It does not return any error indication,
905 because major problems such as dropped connections won't show up till an output
906 flush for non-TLS connections. The smtp_fflush() function is available for
907 checking that: for convenience, TLS output errors are remembered here so that
908 they are also picked up later by smtp_fflush().
910 This function is exposed to the local_scan API; do not change the signature.
914 more further data expected
915 ... optional arguments
921 smtp_printf(const char *format, BOOL more, ...)
926 smtp_vprintf(format, more, ap);
930 /* This is split off so that verify.c:respond_printf() can, in effect, call
931 smtp_printf(), bearing in mind that in C a vararg function can't directly
932 call another vararg function, only a function which accepts a va_list.
934 This function is exposed to the local_scan API; do not change the signature.
936 /*XXX consider passing caller-info in, for string_vformat-onward */
939 smtp_vprintf(const char *format, BOOL more, va_list ap)
941 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
944 /* Use taint-unchecked routines for writing into big_buffer, trusting
945 that we'll never expand it. */
947 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
948 string_from_gstring(&gs);
952 uschar *msg_copy, *cr, *end;
953 msg_copy = string_copy(gs.s);
954 end = msg_copy + gs.ptr;
955 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
956 memmove(cr, cr + 1, (end--) - cr);
957 debug_printf("SMTP>> %s", msg_copy);
962 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
963 smtp_closedown(US"Unexpected error");
964 exim_exit(EXIT_FAILURE);
967 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
968 have had the same. Note: this code is also present in smtp_respond(). It would
969 be tidier to have it only in one place, but when it was added, it was easier to
970 do it that way, so as not to have to mess with the code for the RCPT command,
971 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
973 if (fl.rcpt_in_progress)
975 if (rcpt_smtp_response == NULL)
976 rcpt_smtp_response = string_copy(big_buffer);
977 else if (fl.rcpt_smtp_response_same &&
978 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
979 fl.rcpt_smtp_response_same = FALSE;
980 fl.rcpt_in_progress = FALSE;
983 /* Now write the string */
987 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
989 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
991 smtp_write_error = -1;
996 /*************************************************
997 * Flush SMTP out and check for error *
998 *************************************************/
1000 /* This function isn't currently used within Exim (it detects errors when it
1001 tries to read the next SMTP input), but is available for use in local_scan().
1002 It flushes the output and checks for errors.
1005 Returns: 0 for no error; -1 after an error
1011 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
1015 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
1017 (fflush(smtp_out) != 0)
1019 smtp_write_error = -1;
1021 return smtp_write_error;
1026 /*************************************************
1027 * SMTP command read timeout *
1028 *************************************************/
1030 /* Signal handler for timing out incoming SMTP commands. This attempts to
1033 Argument: signal number (SIGALRM)
1038 command_timeout_handler(int sig)
1040 had_command_timeout = sig;
1045 /*************************************************
1046 * SIGTERM received *
1047 *************************************************/
1049 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1051 Argument: signal number (SIGTERM)
1056 command_sigterm_handler(int sig)
1058 had_command_sigterm = sig;
1064 #ifdef SUPPORT_PROXY
1065 /*************************************************
1066 * Restore socket timeout to previous value *
1067 *************************************************/
1068 /* If the previous value was successfully retrieved, restore
1069 it before returning control to the non-proxy routines
1071 Arguments: fd - File descriptor for input
1072 get_ok - Successfully retrieved previous values
1073 tvtmp - Time struct with previous values
1074 vslen - Length of time struct
1078 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1081 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1084 /*************************************************
1085 * Check if host is required proxy host *
1086 *************************************************/
1087 /* The function determines if inbound host will be a regular smtp host
1088 or if it is configured that it must use Proxy Protocol. A local
1096 check_proxy_protocol_host()
1100 if ( sender_host_address
1101 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1102 sender_host_address, NULL)) == OK)
1105 debug_printf("Detected proxy protocol configured host\n");
1106 proxy_session = TRUE;
1108 return proxy_session;
1112 /*************************************************
1113 * Read data until newline or end of buffer *
1114 *************************************************/
1115 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1116 read an entire buffer and assume there will be nothing past a proxy protocol
1117 header. Our approach normally is to use stdio, but again that relies upon
1118 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1119 reading _nothing_ before client TLS handshake. So we don't want to use the
1120 usual buffering reads which may read enough to block TLS starting.
1122 So unfortunately we're down to "read one byte at a time, with a syscall each,
1123 and expect a little overhead", for all proxy-opened connections which are v1,
1124 just to handle the TLS-on-connect case. Since SSL functions wrap the
1125 underlying fd, we can't assume that we can feed them any already-read content.
1127 We need to know where to read to, the max capacity, and we'll read until we
1128 get a CR and one more character. Let the caller scream if it's CR+!LF.
1130 Return the amount read.
1134 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1136 uschar *to = base + already;
1142 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1143 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1145 cr = memchr(base, '\r', already);
1148 if ((cr - base) < already - 1)
1150 /* \r and presumed \n already within what we have; probably not
1151 actually proxy protocol, but abort cleanly. */
1154 /* \r is last character read, just need one more. */
1158 while (capacity > 0)
1160 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1172 /* reached end without having room for a final newline, abort */
1177 /*************************************************
1178 * Setup host for proxy protocol *
1179 *************************************************/
1180 /* The function configures the connection based on a header from the
1181 inbound host to use Proxy Protocol. The specification is very exact
1182 so exit with an error if do not find the exact required pieces. This
1183 includes an incorrect number of spaces separating args.
1186 Returns: Boolean success
1190 setup_proxy_protocol_host()
1202 struct { /* TCP/UDP over IPv4, len = 12 */
1208 struct { /* TCP/UDP over IPv6, len = 36 */
1209 uint8_t src_addr[16];
1210 uint8_t dst_addr[16];
1214 struct { /* AF_UNIX sockets, len = 216 */
1215 uschar src_addr[108];
1216 uschar dst_addr[108];
1222 /* Temp variables used in PPv2 address:port parsing */
1224 char tmpip[INET_ADDRSTRLEN];
1225 struct sockaddr_in tmpaddr;
1226 char tmpip6[INET6_ADDRSTRLEN];
1227 struct sockaddr_in6 tmpaddr6;
1229 /* We can't read "all data until end" because while SMTP is
1230 server-speaks-first, the TLS handshake is client-speaks-first, so for
1231 TLS-on-connect ports the proxy protocol header will usually be immediately
1232 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1233 reinject data for reading by those. So instead we first read "enough to be
1234 safely read within the header, and figure out how much more to read".
1235 For v1 we will later read to the end-of-line, for v2 we will read based upon
1238 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1239 data is needed total. For v1, where the line looks like:
1240 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1242 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1243 We seem to support that. So, if we read 14 octets then we can tell if we're
1244 v2 or v1. If we're v1, we can continue reading as normal.
1246 If we're v2, we can't slurp up the entire header. We need the length in the
1247 15th & 16th octets, then to read everything after that.
1249 So to safely handle v1 and v2, with client-sent-first supported correctly,
1250 we have to do a minimum of 3 read calls, not 1. Eww.
1253 #define PROXY_INITIAL_READ 14
1254 #define PROXY_V2_HEADER_SIZE 16
1255 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1256 # error Code bug in sizes of data to read for proxy usage
1261 int fd = fileno(smtp_in);
1262 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1263 uschar * iptype; /* To display debug info */
1265 struct timeval tvtmp;
1266 socklen_t vslen = sizeof(struct timeval);
1269 /* Save current socket timeout values */
1270 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1272 /* Proxy Protocol host must send header within a short time
1273 (default 3 seconds) or it's considered invalid */
1274 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1275 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1276 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1281 /* The inbound host was declared to be a Proxy Protocol host, so
1282 don't do a PEEK into the data, actually slurp up enough to be
1283 "safe". Can't take it all because TLS-on-connect clients follow
1284 immediately with TLS handshake. */
1285 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1287 while (ret == -1 && errno == EINTR);
1292 /* For v2, handle reading the length, and then the rest. */
1293 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1298 /* First get the length fields. */
1301 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1302 } while (retmore == -1 && errno == EINTR);
1307 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1309 /* May 2014: haproxy combined the version and command into one byte to
1310 allow two full bytes for the length field in order to proxy SSL
1311 connections. SSL Proxy is not supported in this version of Exim, but
1312 must still separate values here. */
1316 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1320 /* The v2 header will always be 16 bytes per the spec. */
1321 size = 16 + ntohs(hdr.v2.len);
1322 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1323 size, (int)sizeof(hdr));
1325 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1326 amount that we need. Double-check that the size is not unreasonable, then
1328 if (size > sizeof(hdr))
1330 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1338 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1339 } while (retmore == -1 && errno == EINTR);
1343 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1344 } while (ret < size);
1346 } /* end scope for getting rest of data for v2 */
1348 /* At this point: if PROXYv2, we've read the exact size required for all data;
1349 if PROXYv1 then we've read "less than required for any valid line" and should
1352 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1354 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1358 case 0x01: /* PROXY command */
1361 case 0x11: /* TCPv4 address type */
1363 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1364 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1365 if (!string_is_ip_address(US tmpip, NULL))
1367 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1370 proxy_local_address = sender_host_address;
1371 sender_host_address = string_copy(US tmpip);
1372 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1373 proxy_local_port = sender_host_port;
1374 sender_host_port = tmpport;
1375 /* Save dest ip/port */
1376 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1377 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1378 if (!string_is_ip_address(US tmpip, NULL))
1380 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1383 proxy_external_address = string_copy(US tmpip);
1384 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1385 proxy_external_port = tmpport;
1387 case 0x21: /* TCPv6 address type */
1389 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1390 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1391 if (!string_is_ip_address(US tmpip6, NULL))
1393 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1396 proxy_local_address = sender_host_address;
1397 sender_host_address = string_copy(US tmpip6);
1398 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1399 proxy_local_port = sender_host_port;
1400 sender_host_port = tmpport;
1401 /* Save dest ip/port */
1402 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1403 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1404 if (!string_is_ip_address(US tmpip6, NULL))
1406 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1409 proxy_external_address = string_copy(US tmpip6);
1410 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1411 proxy_external_port = tmpport;
1415 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1419 /* Unsupported protocol, keep local connection address */
1421 case 0x00: /* LOCAL command */
1422 /* Keep local connection address for LOCAL */
1427 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1431 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1435 uschar *sp; /* Utility variables follow */
1440 /* get the rest of the line */
1441 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1446 p = string_copy(hdr.v1.line);
1447 end = memchr(p, '\r', ret - 1);
1449 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1451 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1454 *end = '\0'; /* Terminate the string */
1455 size = end + 2 - p; /* Skip header + CRLF */
1456 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1457 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1458 /* Step through the string looking for the required fields. Ensure
1459 strict adherence to required formatting, exit for any error. */
1461 if (!isspace(*(p++)))
1463 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1466 if (!Ustrncmp(p, CCS"TCP4", 4))
1468 else if (!Ustrncmp(p,CCS"TCP6", 4))
1470 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1472 iptype = US"Unknown";
1477 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1481 p += Ustrlen(iptype);
1482 if (!isspace(*(p++)))
1484 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1487 /* Find the end of the arg */
1488 if ((sp = Ustrchr(p, ' ')) == NULL)
1491 debug_printf("Did not find proxied src %s\n", iptype);
1495 if(!string_is_ip_address(p, NULL))
1498 debug_printf("Proxied src arg is not an %s address\n", iptype);
1501 proxy_local_address = sender_host_address;
1502 sender_host_address = p;
1504 if ((sp = Ustrchr(p, ' ')) == NULL)
1507 debug_printf("Did not find proxy dest %s\n", iptype);
1511 if(!string_is_ip_address(p, NULL))
1514 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1517 proxy_external_address = p;
1519 if ((sp = Ustrchr(p, ' ')) == NULL)
1521 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1525 tmp_port = strtol(CCS p, &endc, 10);
1526 if (*endc || tmp_port == 0)
1529 debug_printf("Proxied src port '%s' not an integer\n", p);
1532 proxy_local_port = sender_host_port;
1533 sender_host_port = tmp_port;
1535 if ((sp = Ustrchr(p, '\0')) == NULL)
1537 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1540 tmp_port = strtol(CCS p, &endc, 10);
1541 if (*endc || tmp_port == 0)
1544 debug_printf("Proxy dest port '%s' not an integer\n", p);
1547 proxy_external_port = tmp_port;
1548 /* Already checked for /r /n above. Good V1 header received. */
1552 /* Wrong protocol */
1553 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1554 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1560 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1561 yield = proxy_session;
1563 /* Don't flush any potential buffer contents. Any input on proxyfail
1564 should cause a synchronization failure */
1567 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1572 sender_host_name = NULL;
1573 (void) host_name_lookup();
1574 host_build_sender_fullhost();
1578 f.proxy_session_failed = TRUE;
1580 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1587 /*************************************************
1588 * Read one command line *
1589 *************************************************/
1591 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1592 There are sites that don't do this, and in any case internal SMTP probably
1593 should check only for LF. Consequently, we check here for LF only. The line
1594 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1595 an unknown command. The command is read into the global smtp_cmd_buffer so that
1596 it is available via $smtp_command.
1598 The character reading routine sets up a timeout for each block actually read
1599 from the input (which may contain more than one command). We set up a special
1600 signal handler that closes down the session on a timeout. Control does not
1601 return when it runs.
1604 check_sync if TRUE, check synchronization rules if global option is TRUE
1605 buffer_lim maximum to buffer in lower layer
1607 Returns: a code identifying the command (enumerated above)
1611 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1615 BOOL hadnull = FALSE;
1617 had_command_timeout = 0;
1618 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1620 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1622 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1624 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1632 smtp_cmd_buffer[ptr++] = c;
1635 receive_linecount++; /* For BSMTP errors */
1636 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1638 /* If hit end of file, return pseudo EOF command. Whether we have a
1639 part-line already read doesn't matter, since this is an error state. */
1641 if (c == EOF) return EOF_CMD;
1643 /* Remove any CR and white space at the end of the line, and terminate the
1646 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1647 smtp_cmd_buffer[ptr] = 0;
1649 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1651 /* NULLs are not allowed in SMTP commands */
1653 if (hadnull) return BADCHAR_CMD;
1655 /* Scan command list and return identity, having set the data pointer
1656 to the start of the actual data characters. Check for SMTP synchronization
1659 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1661 #ifdef SUPPORT_PROXY
1662 /* Only allow QUIT command if Proxy Protocol parsing failed */
1663 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1667 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1668 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1669 || smtp_cmd_buffer[p->len] == 0
1670 || smtp_cmd_buffer[p->len] == ' '
1673 if (smtp_inptr < smtp_inend && /* Outstanding input */
1674 p->cmd < sync_cmd_limit && /* Command should sync */
1675 check_sync && /* Local flag set */
1676 smtp_enforce_sync && /* Global flag set */
1677 sender_host_address != NULL && /* Not local input */
1678 !f.sender_host_notsocket) /* Really is a socket */
1681 /* The variables $smtp_command and $smtp_command_argument point into the
1682 unmodified input buffer. A copy of the latter is taken for actual
1683 processing, so that it can be chopped up into separate parts if necessary,
1684 for example, when processing a MAIL command options such as SIZE that can
1685 follow the sender address. */
1687 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1688 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1689 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1690 smtp_cmd_data = smtp_data_buffer;
1692 /* Count non-mail commands from those hosts that are controlled in this
1693 way. The default is all hosts. We don't waste effort checking the list
1694 until we get a non-mail command, but then cache the result to save checking
1695 again. If there's a DEFER while checking the host, assume it's in the list.
1697 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1698 start of each incoming message by fiddling with the value in the table. */
1700 if (!p->is_mail_cmd)
1702 if (count_nonmail == TRUE_UNSET) count_nonmail =
1703 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1704 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1705 return TOO_MANY_NONMAIL_CMD;
1708 /* If there is data for a command that does not expect it, generate the
1711 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1715 #ifdef SUPPORT_PROXY
1716 /* Only allow QUIT command if Proxy Protocol parsing failed */
1717 if (proxy_session && f.proxy_session_failed)
1718 return PROXY_FAIL_IGNORE_CMD;
1721 /* Enforce synchronization for unknown commands */
1723 if ( smtp_inptr < smtp_inend /* Outstanding input */
1724 && check_sync /* Local flag set */
1725 && smtp_enforce_sync /* Global flag set */
1726 && sender_host_address /* Not local input */
1727 && !f.sender_host_notsocket) /* Really is a socket */
1735 /*************************************************
1736 * Forced closedown of call *
1737 *************************************************/
1739 /* This function is called from log.c when Exim is dying because of a serious
1740 disaster, and also from some other places. If an incoming non-batched SMTP
1741 channel is open, it swallows the rest of the incoming message if in the DATA
1742 phase, sends the reply string, and gives an error to all subsequent commands
1743 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1747 message SMTP reply string to send, excluding the code
1753 smtp_closedown(uschar *message)
1755 if (!smtp_in || smtp_batched_input) return;
1756 receive_swallow_smtp();
1757 smtp_printf("421 %s\r\n", FALSE, message);
1759 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1765 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1770 smtp_printf("250 Reset OK\r\n", FALSE);
1774 smtp_printf("421 %s\r\n", FALSE, message);
1782 /*************************************************
1783 * Set up connection info for logging *
1784 *************************************************/
1786 /* This function is called when logging information about an SMTP connection.
1787 It sets up appropriate source information, depending on the type of connection.
1788 If sender_fullhost is NULL, we are at a very early stage of the connection;
1789 just use the IP address.
1792 Returns: a string describing the connection
1796 smtp_get_connection_info(void)
1798 const uschar * hostname = sender_fullhost
1799 ? sender_fullhost : sender_host_address;
1802 return string_sprintf("SMTP connection from %s", hostname);
1804 if (f.sender_host_unknown || f.sender_host_notsocket)
1805 return string_sprintf("SMTP connection from %s", sender_ident);
1808 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1810 if (LOGGING(incoming_interface) && interface_address)
1811 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1812 interface_address, interface_port);
1814 return string_sprintf("SMTP connection from %s", hostname);
1820 /* Append TLS-related information to a log line
1823 g String under construction: allocated string to extend, or NULL
1825 Returns: Allocated string or NULL
1828 s_tlslog(gstring * g)
1830 if (LOGGING(tls_cipher) && tls_in.cipher)
1832 g = string_append(g, 2, US" X=", tls_in.cipher);
1833 #ifdef EXPERIMENTAL_TLS_RESUME
1834 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1835 g = string_catn(g, US"*", 1);
1838 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1839 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1840 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1841 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1842 if (LOGGING(tls_sni) && tls_in.sni)
1843 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1851 s_connhad_log(gstring * g)
1853 uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1854 ? US" C=..." : US" C=";
1856 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1857 if (smtp_connection_had[i] != SCH_NONE)
1859 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1862 for (int i = 0; i < smtp_ch_index; i++)
1864 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1871 /*************************************************
1872 * Log lack of MAIL if so configured *
1873 *************************************************/
1875 /* This function is called when an SMTP session ends. If the log selector
1876 smtp_no_mail is set, write a log line giving some details of what has happened
1877 in the SMTP session.
1884 smtp_log_no_mail(void)
1889 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1892 if (sender_host_authenticated)
1894 g = string_append(g, 2, US" A=", sender_host_authenticated);
1895 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1902 g = s_connhad_log(g);
1904 if (!(s = string_from_gstring(g))) s = US"";
1906 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1907 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1908 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1912 /* Return list of recent smtp commands */
1917 gstring * list = NULL;
1920 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1921 if (smtp_connection_had[i] != SCH_NONE)
1922 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1924 for (int i = 0; i < smtp_ch_index; i++)
1925 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1927 s = string_from_gstring(list);
1928 return s ? s : US"";
1934 /*************************************************
1935 * Check HELO line and set sender_helo_name *
1936 *************************************************/
1938 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1939 the domain name of the sending host, or an ip literal in square brackets. The
1940 argument is placed in sender_helo_name, which is in malloc store, because it
1941 must persist over multiple incoming messages. If helo_accept_junk is set, this
1942 host is permitted to send any old junk (needed for some broken hosts).
1943 Otherwise, helo_allow_chars can be used for rogue characters in general
1944 (typically people want to let in underscores).
1947 s the data portion of the line (already past any white space)
1949 Returns: TRUE or FALSE
1953 check_helo(uschar *s)
1956 uschar *end = s + Ustrlen(s);
1957 BOOL yield = fl.helo_accept_junk;
1959 /* Discard any previous helo name */
1961 sender_helo_name = NULL;
1963 /* Skip tests if junk is permitted. */
1967 /* Allow the new standard form for IPv6 address literals, namely,
1968 [IPv6:....], and because someone is bound to use it, allow an equivalent
1969 IPv4 form. Allow plain addresses as well. */
1976 if (strncmpic(s, US"[IPv6:", 6) == 0)
1977 yield = (string_is_ip_address(s+6, NULL) == 6);
1978 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1979 yield = (string_is_ip_address(s+6, NULL) == 4);
1981 yield = (string_is_ip_address(s+1, NULL) != 0);
1986 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1987 that have been configured (usually underscore - sigh). */
1990 for (yield = TRUE; *s; s++)
1991 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1992 Ustrchr(helo_allow_chars, *s) == NULL)
1998 /* Save argument if OK */
2000 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
2008 /*************************************************
2009 * Extract SMTP command option *
2010 *************************************************/
2012 /* This function picks the next option setting off the end of smtp_cmd_data. It
2013 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
2014 things that can appear there.
2017 name point this at the name
2018 value point this at the data string
2020 Returns: TRUE if found an option
2024 extract_option(uschar **name, uschar **value)
2027 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
2028 while (isspace(*v)) v--;
2030 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
2032 /* Take care to not stop at a space embedded in a quoted local-part */
2034 if ((*v == '"') && (v > smtp_cmd_data + 1))
2035 do v--; while (*v != '"' && v > smtp_cmd_data+1);
2042 while(isalpha(n[-1])) n--;
2043 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2044 if (!isspace(n[-1])) return FALSE;
2050 if (v == smtp_cmd_data) return FALSE;
2062 /*************************************************
2063 * Reset for new message *
2064 *************************************************/
2066 /* This function is called whenever the SMTP session is reset from
2067 within either of the setup functions; also from the daemon loop.
2069 Argument: the stacking pool storage reset point
2074 smtp_reset(void *reset_point)
2076 recipients_list = NULL;
2077 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2078 raw_recipients_count = recipients_count = recipients_list_max = 0;
2079 message_linecount = 0;
2081 acl_added_headers = NULL;
2082 acl_removed_headers = NULL;
2083 f.queue_only_policy = FALSE;
2084 rcpt_smtp_response = NULL;
2085 fl.rcpt_smtp_response_same = TRUE;
2086 fl.rcpt_in_progress = FALSE;
2087 f.deliver_freeze = FALSE; /* Can be set by ACL */
2088 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2089 fake_response = OK; /* Can be set by ACL */
2090 #ifdef WITH_CONTENT_SCAN
2091 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2093 f.submission_mode = FALSE; /* Can be set by ACL */
2094 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2095 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2096 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2097 sending_ip_address = NULL;
2098 return_path = sender_address = NULL;
2099 deliver_localpart_data = deliver_domain_data =
2100 recipient_data = sender_data = NULL; /* Can be set by ACL */
2101 deliver_localpart_parent = deliver_localpart_orig = NULL;
2102 deliver_domain_parent = deliver_domain_orig = NULL;
2103 callout_address = NULL;
2104 submission_name = NULL; /* Can be set by ACL */
2105 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2106 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2107 sender_verified_list = NULL; /* No senders verified */
2108 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2109 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2111 authenticated_sender = NULL;
2112 #ifdef EXPERIMENTAL_BRIGHTMAIL
2114 bmi_verdicts = NULL;
2116 dnslist_domain = dnslist_matched = NULL;
2118 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2119 spf_result_guessed = FALSE;
2121 #ifndef DISABLE_DKIM
2122 dkim_cur_signer = dkim_signers =
2123 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2124 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2125 f.dkim_disable_verify = FALSE;
2126 dkim_collect_input = 0;
2127 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2128 dkim_key_length = 0;
2130 #ifdef SUPPORT_DMARC
2131 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2132 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2133 dmarc_used_domain = NULL;
2135 #ifdef EXPERIMENTAL_ARC
2136 arc_state = arc_state_reason = NULL;
2137 arc_received_instance = 0;
2141 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2142 #ifndef DISABLE_PRDR
2143 prdr_requested = FALSE;
2146 message_smtputf8 = FALSE;
2148 body_linecount = body_zerocount = 0;
2150 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2151 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2152 /* Note that ratelimiters_conn persists across resets. */
2154 /* Reset message ACL variables */
2158 /* The message body variables use malloc store. They may be set if this is
2159 not the first message in an SMTP session and the previous message caused them
2160 to be referenced in an ACL. */
2164 store_free(message_body);
2165 message_body = NULL;
2168 if (message_body_end)
2170 store_free(message_body_end);
2171 message_body_end = NULL;
2174 /* Warning log messages are also saved in malloc store. They are saved to avoid
2175 repetition in the same message, but it seems right to repeat them for different
2178 while (acl_warn_logged)
2180 string_item *this = acl_warn_logged;
2181 acl_warn_logged = acl_warn_logged->next;
2184 store_reset(reset_point);
2185 return store_mark();
2192 /*************************************************
2193 * Initialize for incoming batched SMTP message *
2194 *************************************************/
2196 /* This function is called from smtp_setup_msg() in the case when
2197 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2198 of messages in one file with SMTP commands between them. All errors must be
2199 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2200 relevant. After an error on a sender, or an invalid recipient, the remainder
2201 of the message is skipped. The value of received_protocol is already set.
2204 Returns: > 0 message successfully started (reached DATA)
2205 = 0 QUIT read or end of file reached
2206 < 0 should not occur
2210 smtp_setup_batch_msg(void)
2213 rmark reset_point = store_mark();
2215 /* Save the line count at the start of each transaction - single commands
2216 like HELO and RSET count as whole transactions. */
2218 bsmtp_transaction_linecount = receive_linecount;
2220 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2222 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2223 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2225 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2226 value. The values are 2 larger than the required yield of the function. */
2231 uschar *recipient = NULL;
2232 int start, end, sender_domain, recipient_domain;
2234 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2236 /* The HELO/EHLO commands set sender_address_helo if they have
2237 valid data; otherwise they are ignored, except that they do
2238 a reset of the state. */
2243 check_helo(smtp_cmd_data);
2247 cancel_cutthrough_connection(TRUE, US"RSET received");
2248 reset_point = smtp_reset(reset_point);
2249 bsmtp_transaction_linecount = receive_linecount;
2253 /* The MAIL FROM command requires an address as an operand. All we
2254 do here is to parse it for syntactic correctness. The form "<>" is
2255 a special case which converts into an empty string. The start/end
2256 pointers in the original are not used further for this address, as
2257 it is the canonical extracted address which is all that is kept. */
2260 smtp_mailcmd_count++; /* Count for no-mail log */
2261 if (sender_address != NULL)
2262 /* The function moan_smtp_batch() does not return. */
2263 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2265 if (smtp_cmd_data[0] == 0)
2266 /* The function moan_smtp_batch() does not return. */
2267 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2269 /* Reset to start of message */
2271 cancel_cutthrough_connection(TRUE, US"MAIL received");
2272 reset_point = smtp_reset(reset_point);
2274 /* Apply SMTP rewrite */
2276 raw_sender = rewrite_existflags & rewrite_smtp
2277 /* deconst ok as smtp_cmd_data was not const */
2278 ? US rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL,
2279 FALSE, US"", global_rewrite_rules)
2282 /* Extract the address; the TRUE flag allows <> as valid */
2285 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2289 /* The function moan_smtp_batch() does not return. */
2290 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2292 sender_address = string_copy(raw_sender);
2294 /* Qualify unqualified sender addresses if permitted to do so. */
2297 && sender_address[0] != 0 && sender_address[0] != '@')
2298 if (f.allow_unqualified_sender)
2300 /* deconst ok as sender_address was not const */
2301 sender_address = US rewrite_address_qualify(sender_address, FALSE);
2302 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2303 "and rewritten\n", raw_sender);
2305 /* The function moan_smtp_batch() does not return. */
2307 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2312 /* The RCPT TO command requires an address as an operand. All we do
2313 here is to parse it for syntactic correctness. There may be any number
2314 of RCPT TO commands, specifying multiple senders. We build them all into
2315 a data structure that is in argc/argv format. The start/end values
2316 given by parse_extract_address are not used, as we keep only the
2317 extracted address. */
2320 if (!sender_address)
2321 /* The function moan_smtp_batch() does not return. */
2322 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2324 if (smtp_cmd_data[0] == 0)
2325 /* The function moan_smtp_batch() does not return. */
2326 moan_smtp_batch(smtp_cmd_buffer,
2327 "501 RCPT TO must have an address operand");
2329 /* Check maximum number allowed */
2331 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2332 /* The function moan_smtp_batch() does not return. */
2333 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2334 recipients_max_reject? "552": "452");
2336 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2337 recipient address */
2339 recipient = rewrite_existflags & rewrite_smtp
2340 /* deconst ok as smtp_cmd_data was not const */
2341 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2342 global_rewrite_rules)
2345 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2346 &recipient_domain, FALSE);
2349 /* The function moan_smtp_batch() does not return. */
2350 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2352 /* If the recipient address is unqualified, qualify it if permitted. Then
2353 add it to the list of recipients. */
2355 if (!recipient_domain)
2356 if (f.allow_unqualified_recipient)
2358 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2360 /* deconst ok as recipient was not const */
2361 recipient = US rewrite_address_qualify(recipient, TRUE);
2363 /* The function moan_smtp_batch() does not return. */
2365 moan_smtp_batch(smtp_cmd_buffer,
2366 "501 recipient address must contain a domain");
2368 receive_add_recipient(recipient, -1);
2372 /* The DATA command is legal only if it follows successful MAIL FROM
2373 and RCPT TO commands. This function is complete when a valid DATA
2374 command is encountered. */
2377 if (!sender_address || recipients_count <= 0)
2378 /* The function moan_smtp_batch() does not return. */
2379 if (!sender_address)
2380 moan_smtp_batch(smtp_cmd_buffer,
2381 "503 MAIL FROM:<sender> command must precede DATA");
2383 moan_smtp_batch(smtp_cmd_buffer,
2384 "503 RCPT TO:<recipient> must precede DATA");
2387 done = 3; /* DATA successfully achieved */
2388 message_ended = END_NOTENDED; /* Indicate in middle of message */
2393 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2400 bsmtp_transaction_linecount = receive_linecount;
2411 /* The function moan_smtp_batch() does not return. */
2412 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2417 /* The function moan_smtp_batch() does not return. */
2418 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2423 /* The function moan_smtp_batch() does not return. */
2424 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2429 return done - 2; /* Convert yield values */
2437 smtp_log_tls_fail(uschar * errstr)
2439 uschar * conn_info = smtp_get_connection_info();
2441 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2442 /* I'd like to get separated H= here, but too hard for now */
2444 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2458 socklen_t len = sizeof(is_fastopen);
2460 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2461 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2463 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2468 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2469 f.tcp_in_fastopen = TRUE;
2472 else DEBUG(D_receive)
2473 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2475 # elif defined(TCP_INFO)
2476 struct tcp_info tinfo;
2477 socklen_t len = sizeof(tinfo);
2479 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2480 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2481 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2484 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2485 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2489 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2492 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2493 f.tcp_in_fastopen = TRUE;
2495 else DEBUG(D_receive)
2496 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2502 /*************************************************
2503 * Start an SMTP session *
2504 *************************************************/
2506 /* This function is called at the start of an SMTP session. Thereafter,
2507 smtp_setup_msg() is called to initiate each separate message. This
2508 function does host-specific testing, and outputs the banner line.
2511 Returns: FALSE if the session can not continue; something has
2512 gone wrong, or the connection to the host is blocked
2516 smtp_start_session(void)
2519 uschar *user_msg, *log_msg;
2524 gettimeofday(&smtp_connection_start, NULL);
2525 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2526 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2529 /* Default values for certain variables */
2531 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2532 smtp_mailcmd_count = 0;
2533 count_nonmail = TRUE_UNSET;
2534 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2535 smtp_delay_mail = smtp_rlm_base;
2536 fl.auth_advertised = FALSE;
2537 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2538 f.pipelining_enable = TRUE;
2539 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2540 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2542 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2543 authentication settings from -oMaa to remain in force. */
2545 if (!host_checking && !f.sender_host_notsocket)
2546 sender_host_auth_pubname = sender_host_authenticated = NULL;
2547 authenticated_by = NULL;
2550 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2551 tls_in.ourcert = tls_in.peercert = NULL;
2553 tls_in.ocsp = OCSP_NOT_REQ;
2554 fl.tls_advertised = FALSE;
2556 fl.dsn_advertised = FALSE;
2558 fl.smtputf8_advertised = FALSE;
2561 /* Reset ACL connection variables */
2565 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2567 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, TRUE);
2569 smtp_cmd_buffer[0] = 0;
2570 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2572 /* For batched input, the protocol setting can be overridden from the
2573 command line by a trusted caller. */
2575 if (smtp_batched_input)
2577 if (!received_protocol) received_protocol = US"local-bsmtp";
2580 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2581 reset later if any of EHLO/AUTH/STARTTLS are received. */
2585 (sender_host_address ? protocols : protocols_local) [pnormal];
2587 /* Set up the buffer for inputting using direct read() calls, and arrange to
2588 call the local functions instead of the standard C ones. Place a NUL at the
2589 end of the buffer to safety-stop C-string reads from it. */
2591 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2592 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2593 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2595 receive_getc = smtp_getc;
2596 receive_getbuf = smtp_getbuf;
2597 receive_get_cache = smtp_get_cache;
2598 receive_ungetc = smtp_ungetc;
2599 receive_feof = smtp_feof;
2600 receive_ferror = smtp_ferror;
2601 receive_smtp_buffered = smtp_buffered;
2602 lwr_receive_getc = NULL;
2603 lwr_receive_getbuf = NULL;
2604 lwr_receive_ungetc = NULL;
2605 smtp_inptr = smtp_inend = smtp_inbuffer;
2606 smtp_had_eof = smtp_had_error = 0;
2608 /* Set up the message size limit; this may be host-specific */
2610 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2611 if (expand_string_message)
2613 if (thismessage_size_limit == -1)
2614 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2615 "%s", expand_string_message);
2617 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2618 "%s", expand_string_message);
2619 smtp_closedown(US"Temporary local problem - please try later");
2623 /* When a message is input locally via the -bs or -bS options, sender_host_
2624 unknown is set unless -oMa was used to force an IP address, in which case it
2625 is checked like a real remote connection. When -bs is used from inetd, this
2626 flag is not set, causing the sending host to be checked. The code that deals
2627 with IP source routing (if configured) is never required for -bs or -bS and
2628 the flag sender_host_notsocket is used to suppress it.
2630 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2631 reserve for certain hosts and/or networks. */
2633 if (!f.sender_host_unknown)
2636 BOOL reserved_host = FALSE;
2638 /* Look up IP options (source routing info) on the socket if this is not an
2639 -oMa "host", and if any are found, log them and drop the connection.
2641 Linux (and others now, see below) is different to everyone else, so there
2642 has to be some conditional compilation here. Versions of Linux before 2.1.15
2643 used a structure whose name was "options". Somebody finally realized that
2644 this name was silly, and it got changed to "ip_options". I use the
2645 newer name here, but there is a fudge in the script that sets up os.h
2646 to define a macro in older Linux systems.
2648 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2649 glibc 2, which has chosen ip_opts for the structure name. This is now
2650 really a glibc thing rather than a Linux thing, so the condition name
2651 has been changed to reflect this. It is relevant also to GNU/Hurd.
2653 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2654 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2655 a special macro defined in the os.h file.
2657 Some DGUX versions on older hardware appear not to support IP options at
2658 all, so there is now a general macro which can be set to cut out this
2661 How to do this properly in IPv6 is not yet known. */
2663 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2665 #ifdef GLIBC_IP_OPTIONS
2666 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2671 #elif defined DARWIN_IP_OPTIONS
2677 if (!host_checking && !f.sender_host_notsocket)
2680 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2681 struct ip_options *ipopt = store_get(optlen, FALSE);
2683 struct ip_opts ipoptblock;
2684 struct ip_opts *ipopt = &ipoptblock;
2685 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2687 struct ipoption ipoptblock;
2688 struct ipoption *ipopt = &ipoptblock;
2689 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2692 /* Occasional genuine failures of getsockopt() have been seen - for
2693 example, "reset by peer". Therefore, just log and give up on this
2694 call, unless the error is ENOPROTOOPT. This error is given by systems
2695 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2696 of writing. So for that error, carry on - we just can't do an IP options
2699 DEBUG(D_receive) debug_printf("checking for IP options\n");
2701 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2704 if (errno != ENOPROTOOPT)
2706 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2707 host_and_ident(FALSE), strerror(errno));
2708 smtp_printf("451 SMTP service not available\r\n", FALSE);
2713 /* Deal with any IP options that are set. On the systems I have looked at,
2714 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2715 more logging data than will fit in big_buffer. Nevertheless, after somebody
2716 questioned this code, I've added in some paranoid checking. */
2718 else if (optlen > 0)
2720 uschar *p = big_buffer;
2721 uschar *pend = big_buffer + big_buffer_size;
2724 struct in_addr addr;
2727 uschar *optstart = US (ipopt->__data);
2729 uschar *optstart = US (ipopt->ip_opts);
2731 uschar *optstart = US (ipopt->ipopt_list);
2734 DEBUG(D_receive) debug_printf("IP options exist\n");
2736 Ustrcpy(p, "IP options on incoming call:");
2739 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2752 if (!string_format(p, pend-p, " %s [@%s",
2753 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2755 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2757 inet_ntoa(ipopt->ip_dst)))
2759 inet_ntoa(ipopt->ipopt_dst)))
2767 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2769 while (optcount-- > 0)
2771 memcpy(&addr, adptr, sizeof(addr));
2772 if (!string_format(p, pend - p - 1, "%s%s",
2773 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2779 adptr += sizeof(struct in_addr);
2787 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2790 for (int i = 0; i < opt[1]; i++)
2791 p += sprintf(CS p, "%2.2x ", opt[i]);
2799 log_write(0, LOG_MAIN, "%s", big_buffer);
2801 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2803 log_write(0, LOG_MAIN|LOG_REJECT,
2804 "connection from %s refused (IP options)", host_and_ident(FALSE));
2806 smtp_printf("554 SMTP service not available\r\n", FALSE);
2810 /* Length of options = 0 => there are no options */
2812 else DEBUG(D_receive) debug_printf("no IP options found\n");
2814 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2816 /* Set keep-alive in socket options. The option is on by default. This
2817 setting is an attempt to get rid of some hanging connections that stick in
2818 read() when the remote end (usually a dialup) goes away. */
2820 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2821 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2823 /* If the current host matches host_lookup, set the name by doing a
2824 reverse lookup. On failure, sender_host_name will be NULL and
2825 host_lookup_failed will be TRUE. This may or may not be serious - optional
2828 if (verify_check_host(&host_lookup) == OK)
2830 (void)host_name_lookup();
2831 host_build_sender_fullhost();
2834 /* Delay this until we have the full name, if it is looked up. */
2836 set_process_info("handling incoming connection from %s",
2837 host_and_ident(FALSE));
2839 /* Expand smtp_receive_timeout, if needed */
2841 if (smtp_receive_timeout_s)
2844 if ( !(exp = expand_string(smtp_receive_timeout_s))
2846 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2848 log_write(0, LOG_MAIN|LOG_PANIC,
2849 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2852 /* Test for explicit connection rejection */
2854 if (verify_check_host(&host_reject_connection) == OK)
2856 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2857 "from %s (host_reject_connection)", host_and_ident(FALSE));
2858 smtp_printf("554 SMTP service not available\r\n", FALSE);
2862 /* Test with TCP Wrappers if so configured. There is a problem in that
2863 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2864 such as disks dying. In these cases, it is desirable to reject with a 4xx
2865 error instead of a 5xx error. There isn't a "right" way to detect such
2866 problems. The following kludge is used: errno is zeroed before calling
2867 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2868 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2871 #ifdef USE_TCP_WRAPPERS
2873 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2874 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2875 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2876 expand_string_message);
2878 if (!hosts_ctl(tcp_wrappers_name,
2879 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2880 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2881 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2883 if (errno == 0 || errno == ENOENT)
2885 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2886 log_write(L_connection_reject,
2887 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2888 "(tcp wrappers)", host_and_ident(FALSE));
2889 smtp_printf("554 SMTP service not available\r\n", FALSE);
2893 int save_errno = errno;
2894 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2895 "errno value %d\n", save_errno);
2896 log_write(L_connection_reject,
2897 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2898 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2899 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2905 /* Check for reserved slots. The value of smtp_accept_count has already been
2906 incremented to include this process. */
2908 if (smtp_accept_max > 0 &&
2909 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2911 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2913 log_write(L_connection_reject,
2914 LOG_MAIN, "temporarily refused connection from %s: not in "
2915 "reserve list: connected=%d max=%d reserve=%d%s",
2916 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2917 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2918 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2919 "please try again later\r\n", FALSE, smtp_active_hostname);
2922 reserved_host = TRUE;
2925 /* If a load level above which only messages from reserved hosts are
2926 accepted is set, check the load. For incoming calls via the daemon, the
2927 check is done in the superior process if there are no reserved hosts, to
2928 save a fork. In all cases, the load average will already be available
2929 in a global variable at this point. */
2931 if (smtp_load_reserve >= 0 &&
2932 load_average > smtp_load_reserve &&
2934 verify_check_host(&smtp_reserve_hosts) != OK)
2936 log_write(L_connection_reject,
2937 LOG_MAIN, "temporarily refused connection from %s: not in "
2938 "reserve list and load average = %.2f", host_and_ident(FALSE),
2939 (double)load_average/1000.0);
2940 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2941 smtp_active_hostname);
2945 /* Determine whether unqualified senders or recipients are permitted
2946 for this host. Unfortunately, we have to do this every time, in order to
2947 set the flags so that they can be inspected when considering qualifying
2948 addresses in the headers. For a site that permits no qualification, this
2949 won't take long, however. */
2951 f.allow_unqualified_sender =
2952 verify_check_host(&sender_unqualified_hosts) == OK;
2954 f.allow_unqualified_recipient =
2955 verify_check_host(&recipient_unqualified_hosts) == OK;
2957 /* Determine whether HELO/EHLO is required for this host. The requirement
2958 can be hard or soft. */
2960 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2961 if (!fl.helo_required)
2962 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2964 /* Determine whether this hosts is permitted to send syntactic junk
2965 after a HELO or EHLO command. */
2967 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2970 /* For batch SMTP input we are now done. */
2972 if (smtp_batched_input) return TRUE;
2974 /* If valid Proxy Protocol source is connecting, set up session.
2975 * Failure will not allow any SMTP function other than QUIT. */
2977 #ifdef SUPPORT_PROXY
2978 proxy_session = FALSE;
2979 f.proxy_session_failed = FALSE;
2980 if (check_proxy_protocol_host())
2981 setup_proxy_protocol_host();
2984 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2985 smtps port for use with older style SSL MTAs. */
2988 if (tls_in.on_connect)
2990 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2991 return smtp_log_tls_fail(user_msg);
2992 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2996 /* Run the connect ACL if it exists */
2999 if (acl_smtp_connect)
3002 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
3005 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
3010 /* Output the initial message for a two-way SMTP connection. It may contain
3011 newlines, which then cause a multi-line response to be given. */
3013 code = US"220"; /* Default status code */
3014 esc = US""; /* Default extended status code */
3015 esclen = 0; /* Length of esc */
3019 if (!(s = expand_string(smtp_banner)))
3020 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
3021 "failed: %s", smtp_banner, expand_string_message);
3027 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
3031 esclen = codelen - 4;
3035 /* Remove any terminating newlines; might as well remove trailing space too */
3038 while (p > s && isspace(p[-1])) p--;
3041 /* It seems that CC:Mail is braindead, and assumes that the greeting message
3042 is all contained in a single IP packet. The original code wrote out the
3043 greeting using several calls to fprint/fputc, and on busy servers this could
3044 cause it to be split over more than one packet - which caused CC:Mail to fall
3045 over when it got the second part of the greeting after sending its first
3046 command. Sigh. To try to avoid this, build the complete greeting message
3047 first, and output it in one fell swoop. This gives a better chance of it
3048 ending up as a single packet. */
3050 ss = string_get(256);
3053 do /* At least once, in case we have an empty string */
3056 uschar *linebreak = Ustrchr(p, '\n');
3057 ss = string_catn(ss, code, 3);
3061 ss = string_catn(ss, US" ", 1);
3065 len = linebreak - p;
3066 ss = string_catn(ss, US"-", 1);
3068 ss = string_catn(ss, esc, esclen);
3069 ss = string_catn(ss, p, len);
3070 ss = string_catn(ss, US"\r\n", 2);
3076 /* Before we write the banner, check that there is no input pending, unless
3077 this synchronisation check is disabled. */
3079 #ifndef DISABLE_PIPE_CONNECT
3080 fl.pipe_connect_acceptable =
3081 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3084 if (fl.pipe_connect_acceptable)
3085 f.smtp_in_early_pipe_used = TRUE;
3091 unsigned n = smtp_inend - smtp_inptr;
3092 if (n > 128) n = 128;
3094 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3095 "synchronization error (input sent without waiting for greeting): "
3096 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3097 string_printing(string_copyn(smtp_inptr, n)));
3098 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3102 /* Now output the banner */
3103 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3106 #ifndef DISABLE_PIPE_CONNECT
3107 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3111 string_from_gstring(ss));
3113 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3114 handshake arrived. If so we must have managed a TFO. */
3117 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3127 /*************************************************
3128 * Handle SMTP syntax and protocol errors *
3129 *************************************************/
3131 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3132 to do so. Then transmit the error response. The return value depends on the
3133 number of syntax and protocol errors in this SMTP session.
3136 type error type, given as a log flag bit
3137 code response code; <= 0 means don't send a response
3138 data data to reflect in the response (can be NULL)
3139 errmess the error message
3141 Returns: -1 limit of syntax/protocol errors NOT exceeded
3142 +1 limit of syntax/protocol errors IS exceeded
3144 These values fit in with the values of the "done" variable in the main
3145 processing loop in smtp_setup_msg(). */
3148 synprot_error(int type, int code, uschar *data, uschar *errmess)
3152 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3153 type == L_smtp_syntax_error ? "syntax" : "protocol",
3154 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3156 if (++synprot_error_count > smtp_max_synprot_errors)
3159 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3160 "syntax or protocol errors (last command was \"%s\", %s)",
3161 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3162 string_from_gstring(s_connhad_log(NULL))
3168 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3169 data ? data : US"", data ? US": " : US"", errmess);
3171 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3180 /*************************************************
3181 * Send SMTP response, possibly multiline *
3182 *************************************************/
3184 /* There are, it seems, broken clients out there that cannot handle multiline
3185 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3186 output nothing for non-final calls, and only the first line for anything else.
3189 code SMTP code, may involve extended status codes
3190 codelen length of smtp code; if > 4 there's an ESC
3191 final FALSE if the last line isn't the final line
3192 msg message text, possibly containing newlines
3198 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3203 if (!final && f.no_multiline_responses) return;
3208 esclen = codelen - 4;
3211 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3212 have had the same. Note: this code is also present in smtp_printf(). It would
3213 be tidier to have it only in one place, but when it was added, it was easier to
3214 do it that way, so as not to have to mess with the code for the RCPT command,
3215 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3217 if (fl.rcpt_in_progress)
3219 if (rcpt_smtp_response == NULL)
3220 rcpt_smtp_response = string_copy(msg);
3221 else if (fl.rcpt_smtp_response_same &&
3222 Ustrcmp(rcpt_smtp_response, msg) != 0)
3223 fl.rcpt_smtp_response_same = FALSE;
3224 fl.rcpt_in_progress = FALSE;
3227 /* Now output the message, splitting it up into multiple lines if necessary.
3228 We only handle pipelining these responses as far as nonfinal/final groups,
3229 not the whole MAIL/RCPT/DATA response set. */
3233 uschar *nl = Ustrchr(msg, '\n');
3236 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3239 else if (nl[1] == 0 || f.no_multiline_responses)
3241 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3242 (int)(nl - msg), msg);
3247 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3249 Uskip_whitespace(&msg);
3257 /*************************************************
3258 * Parse user SMTP message *
3259 *************************************************/
3261 /* This function allows for user messages overriding the response code details
3262 by providing a suitable response code string at the start of the message
3263 user_msg. Check the message for starting with a response code and optionally an
3264 extended status code. If found, check that the first digit is valid, and if so,
3265 change the code pointer and length to use the replacement. An invalid code
3266 causes a panic log; in this case, if the log messages is the same as the user
3267 message, we must also adjust the value of the log message to show the code that
3268 is actually going to be used (the original one).
3270 This function is global because it is called from receive.c as well as within
3273 Note that the code length returned includes the terminating whitespace
3274 character, which is always included in the regex match.
3277 code SMTP code, may involve extended status codes
3278 codelen length of smtp code; if > 4 there's an ESC
3280 log_msg optional log message, to be adjusted with the new SMTP code
3281 check_valid if true, verify the response code
3287 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3293 if (!msg || !*msg) return;
3295 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3296 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3298 if (check_valid && (*msg)[0] != (*code)[0])
3300 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3301 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3302 if (log_msg != NULL && *log_msg == *msg)
3303 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3308 *codelen = ovector[1]; /* Includes final space */
3310 *msg += ovector[1]; /* Chop the code off the message */
3317 /*************************************************
3318 * Handle an ACL failure *
3319 *************************************************/
3321 /* This function is called when acl_check() fails. As well as calls from within
3322 this module, it is called from receive.c for an ACL after DATA. It sorts out
3323 logging the incident, and sends the error response. A message containing
3324 newlines is turned into a multiline SMTP response, but for logging, only the
3327 There's a table of default permanent failure response codes to use in
3328 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3329 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3330 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3331 state, because there are broken clients that try VRFY before RCPT. A 5xx
3332 response should be given only when the address is positively known to be
3333 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3334 no explicit code, but if there is one we let it know best.
3335 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3337 From Exim 4.63, it is possible to override the response code details by
3338 providing a suitable response code string at the start of the message provided
3339 in user_msg. The code's first digit is checked for validity.
3342 where where the ACL was called from
3344 user_msg a message that can be included in an SMTP response
3345 log_msg a message for logging
3347 Returns: 0 in most cases
3348 2 if the failure code was FAIL_DROP, in which case the
3349 SMTP connection should be dropped (this value fits with the
3350 "done" variable in smtp_setup_msg() below)
3354 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3356 BOOL drop = rc == FAIL_DROP;
3360 uschar *sender_info = US"";
3362 #ifdef WITH_CONTENT_SCAN
3363 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3365 where == ACL_WHERE_PREDATA ? US"DATA" :
3366 where == ACL_WHERE_DATA ? US"after DATA" :
3367 #ifndef DISABLE_PRDR
3368 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3371 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3372 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3374 if (drop) rc = FAIL;
3376 /* Set the default SMTP code, and allow a user message to change it. */
3378 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3379 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3380 where != ACL_WHERE_VRFY);
3382 /* We used to have sender_address here; however, there was a bug that was not
3383 updating sender_address after a rewrite during a verify. When this bug was
3384 fixed, sender_address at this point became the rewritten address. I'm not sure
3385 this is what should be logged, so I've changed to logging the unrewritten
3386 address to retain backward compatibility. */
3388 #ifndef WITH_CONTENT_SCAN
3389 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3391 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3394 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3395 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3396 sender_host_authenticated ? US" A=" : US"",
3397 sender_host_authenticated ? sender_host_authenticated : US"",
3398 sender_host_authenticated && authenticated_id ? US":" : US"",
3399 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3403 /* If there's been a sender verification failure with a specific message, and
3404 we have not sent a response about it yet, do so now, as a preliminary line for
3405 failures, but not defers. However, always log it for defer, and log it for fail
3406 unless the sender_verify_fail log selector has been turned off. */
3408 if (sender_verified_failed &&
3409 !testflag(sender_verified_failed, af_sverify_told))
3411 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3412 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3414 setflag(sender_verified_failed, af_sverify_told);
3416 if (rc != FAIL || LOGGING(sender_verify_fail))
3417 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3418 host_and_ident(TRUE),
3419 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3420 sender_verified_failed->address,
3421 (sender_verified_failed->message == NULL)? US"" :
3422 string_sprintf(": %s", sender_verified_failed->message));
3424 if (rc == FAIL && sender_verified_failed->user_message)
3425 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3426 testflag(sender_verified_failed, af_verify_pmfail)?
3427 "Postmaster verification failed while checking <%s>\n%s\n"
3428 "Several RFCs state that you are required to have a postmaster\n"
3429 "mailbox for each mail domain. This host does not accept mail\n"
3430 "from domains whose servers reject the postmaster address."
3432 testflag(sender_verified_failed, af_verify_nsfail)?
3433 "Callback setup failed while verifying <%s>\n%s\n"
3434 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3435 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3436 "RFC requirements, and stops you from receiving standard bounce\n"
3437 "messages. This host does not accept mail from domains whose servers\n"
3440 "Verification failed for <%s>\n%s",
3441 sender_verified_failed->address,
3442 sender_verified_failed->user_message));
3444 fl.rcpt_in_progress = save_rcpt_in_progress;
3447 /* Sort out text for logging */
3449 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3450 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3452 /* Send permanent failure response to the command, but the code used isn't
3453 always a 5xx one - see comments at the start of this function. If the original
3454 rc was FAIL_DROP we drop the connection and yield 2. */
3457 smtp_respond(smtp_code, codelen, TRUE,
3458 user_msg ? user_msg : US"Administrative prohibition");
3460 /* Send temporary failure response to the command. Don't give any details,
3461 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3462 verb, and for a header verify when smtp_return_error_details is set.
3464 This conditional logic is all somewhat of a mess because of the odd
3465 interactions between temp_details and return_error_details. One day it should
3466 be re-implemented in a tidier fashion. */
3469 if (f.acl_temp_details && user_msg)
3471 if ( smtp_return_error_details
3472 && sender_verified_failed
3473 && sender_verified_failed->message
3475 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3477 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3480 smtp_respond(smtp_code, codelen, TRUE,
3481 US"Temporary local problem - please try later");
3483 /* Log the incident to the logs that are specified by log_reject_target
3484 (default main, reject). This can be empty to suppress logging of rejections. If
3485 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3486 is closing if required and return 2. */
3488 if (log_reject_target != 0)
3491 gstring * g = s_tlslog(NULL);
3492 uschar * tls = string_from_gstring(g);
3493 if (!tls) tls = US"";
3495 uschar * tls = US"";
3497 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3498 log_reject_target, "%s%s%s %s%srejected %s%s",
3499 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3500 host_and_ident(TRUE),
3503 rc == FAIL ? US"" : US"temporarily ",
3507 if (!drop) return 0;
3509 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3510 smtp_get_connection_info());
3512 /* Run the not-quit ACL, but without any custom messages. This should not be a
3513 problem, because we get here only if some other ACL has issued "drop", and
3514 in that case, *its* custom messages will have been used above. */
3516 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3523 /*************************************************
3524 * Handle SMTP exit when QUIT is not given *
3525 *************************************************/
3527 /* This function provides a logging/statistics hook for when an SMTP connection
3528 is dropped on the floor or the other end goes away. It's a global function
3529 because it's called from receive.c as well as this module. As well as running
3530 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3531 response, either with a custom message from the ACL, or using a default. There
3532 is one case, however, when no message is output - after "drop". In that case,
3533 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3534 passed to this function.
3536 In case things go wrong while processing this function, causing an error that
3537 may re-enter this function, there is a recursion check.
3540 reason What $smtp_notquit_reason will be set to in the ACL;
3541 if NULL, the ACL is not run
3542 code The error code to return as part of the response
3543 defaultrespond The default message if there's no user_msg
3549 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3552 uschar *user_msg = NULL;
3553 uschar *log_msg = NULL;
3555 /* Check for recursive call */
3557 if (fl.smtp_exit_function_called)
3559 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3563 fl.smtp_exit_function_called = TRUE;
3565 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3567 if (acl_smtp_notquit && reason)
3569 smtp_notquit_reason = reason;
3570 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3571 &log_msg)) == ERROR)
3572 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3576 /* If the connection was dropped, we certainly are no longer talking TLS */
3577 tls_in.active.sock = -1;
3579 /* Write an SMTP response if we are expected to give one. As the default
3580 responses are all internal, they should be reasonable size. */
3582 if (code && defaultrespond)
3585 smtp_respond(code, 3, TRUE, user_msg);
3591 va_start(ap, defaultrespond);
3592 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3594 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3603 /*************************************************
3604 * Verify HELO argument *
3605 *************************************************/
3607 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3608 matched. It is also called from ACL processing if verify = helo is used and
3609 verification was not previously tried (i.e. helo_try_verify_hosts was not
3610 matched). The result of its processing is to set helo_verified and
3611 helo_verify_failed. These variables should both be FALSE for this function to
3614 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3615 for IPv6 ::ffff: literals.
3618 Returns: TRUE if testing was completed;
3619 FALSE on a temporary failure
3623 smtp_verify_helo(void)
3627 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3630 if (sender_helo_name == NULL)
3632 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3635 /* Deal with the case of -bs without an IP address */
3637 else if (sender_host_address == NULL)
3639 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3640 f.helo_verified = TRUE;
3643 /* Deal with the more common case when there is a sending IP address */
3645 else if (sender_helo_name[0] == '[')
3647 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3648 Ustrlen(sender_host_address)) == 0;
3651 if (!f.helo_verified)
3653 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3654 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3655 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3660 { if (f.helo_verified) debug_printf("matched host address\n"); }
3663 /* Do a reverse lookup if one hasn't already given a positive or negative
3664 response. If that fails, or the name doesn't match, try checking with a forward
3669 if (sender_host_name == NULL && !host_lookup_failed)
3670 yield = host_name_lookup() != DEFER;
3672 /* If a host name is known, check it and all its aliases. */
3674 if (sender_host_name)
3675 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3677 sender_helo_dnssec = sender_host_dnssec;
3678 HDEBUG(D_receive) debug_printf("matched host name\n");
3682 uschar **aliases = sender_host_aliases;
3684 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3686 sender_helo_dnssec = sender_host_dnssec;
3690 HDEBUG(D_receive) if (f.helo_verified)
3691 debug_printf("matched alias %s\n", *(--aliases));
3694 /* Final attempt: try a forward lookup of the helo name */
3696 if (!f.helo_verified)
3700 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3702 {.request = US"*", .require = US""};
3704 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3706 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3707 NULL, NULL, NULL, &d, NULL, NULL);
3708 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3709 for (host_item * hh = &h; hh; hh = hh->next)
3710 if (Ustrcmp(hh->address, sender_host_address) == 0)
3712 f.helo_verified = TRUE;
3713 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3715 debug_printf("IP address for %s matches calling address\n"
3716 "Forward DNS security status: %sverified\n",
3717 sender_helo_name, sender_helo_dnssec ? "" : "un");
3723 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3730 /*************************************************
3731 * Send user response message *
3732 *************************************************/
3734 /* This function is passed a default response code and a user message. It calls
3735 smtp_message_code() to check and possibly modify the response code, and then
3736 calls smtp_respond() to transmit the response. I put this into a function
3737 just to avoid a lot of repetition.
3740 code the response code
3741 user_msg the user message
3747 smtp_user_msg(uschar *code, uschar *user_msg)
3750 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3751 smtp_respond(code, len, TRUE, user_msg);
3757 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3759 const uschar *set_id = NULL;
3762 /* Run the checking code, passing the remainder of the command line as
3763 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3764 it as the only set numerical variable. The authenticator may set $auth<n>
3765 and also set other numeric variables. The $auth<n> variables are preferred
3766 nowadays; the numerical variables remain for backwards compatibility.
3768 Afterwards, have a go at expanding the set_id string, even if
3769 authentication failed - for bad passwords it can be useful to log the
3770 userid. On success, require set_id to expand and exist, and put it in
3771 authenticated_id. Save this in permanent store, as the working store gets
3772 reset at HELO, RSET, etc. */
3774 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3776 expand_nlength[0] = 0; /* $0 contains nothing */
3778 rc = (au->info->servercode)(au, smtp_cmd_data);
3779 if (au->set_id) set_id = expand_string(au->set_id);
3780 expand_nmax = -1; /* Reset numeric variables */
3781 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3783 /* The value of authenticated_id is stored in the spool file and printed in
3784 log lines. It must not contain binary zeros or newline characters. In
3785 normal use, it never will, but when playing around or testing, this error
3786 can (did) happen. To guard against this, ensure that the id contains only
3787 printing characters. */
3789 if (set_id) set_id = string_printing(set_id);
3791 /* For the non-OK cases, set up additional logging data if set_id
3795 set_id = set_id && *set_id
3796 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3798 /* Switch on the result */
3803 if (!au->set_id || set_id) /* Complete success */
3805 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3806 sender_host_authenticated = au->name;
3807 sender_host_auth_pubname = au->public_name;
3808 authentication_failed = FALSE;
3809 authenticated_fail_id = NULL; /* Impossible to already be set? */
3812 (sender_host_address ? protocols : protocols_local)
3813 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3814 *s = *ss = US"235 Authentication succeeded";
3815 authenticated_by = au;
3819 /* Authentication succeeded, but we failed to expand the set_id string.
3820 Treat this as a temporary error. */
3822 auth_defer_msg = expand_string_message;
3826 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3827 *s = string_sprintf("435 Unable to authenticate at present%s",
3828 auth_defer_user_msg);
3829 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3830 set_id, auth_defer_msg);
3834 *s = *ss = US"501 Invalid base64 data";
3838 *s = *ss = US"501 Authentication cancelled";
3842 *s = *ss = US"553 Initial data not expected";
3846 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3847 *s = US"535 Incorrect authentication data";
3848 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3852 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3853 *s = US"435 Internal error";
3854 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3855 "check", set_id, rc);
3867 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3870 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3872 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3874 rd = Ustrlen(recipient) + 1;
3875 /* deconst ok as *recipient was not const */
3876 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3879 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3881 log_write(L_smtp_syntax_error,
3882 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3883 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3891 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3894 incomplete_transaction_log(US"QUIT");
3897 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3899 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3904 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_CORK, US &on, sizeof(on));
3908 smtp_respond(US"221", 3, TRUE, *user_msgp);
3910 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3913 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3916 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3917 smtp_get_connection_info());
3922 smtp_rset_handler(void)
3925 incomplete_transaction_log(US"RSET");
3926 smtp_printf("250 Reset OK\r\n", FALSE);
3927 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3932 /*************************************************
3933 * Initialize for SMTP incoming message *
3934 *************************************************/
3936 /* This function conducts the initial dialogue at the start of an incoming SMTP
3937 message, and builds a list of recipients. However, if the incoming message
3938 is part of a batch (-bS option) a separate function is called since it would
3939 be messy having tests splattered about all over this function. This function
3940 therefore handles the case where interaction is occurring. The input and output
3941 files are set up in smtp_in and smtp_out.
3943 The global recipients_list is set to point to a vector of recipient_item
3944 blocks, whose number is given by recipients_count. This is extended by the
3945 receive_add_recipient() function. The global variable sender_address is set to
3946 the sender's address. The yield is +1 if a message has been successfully
3947 started, 0 if a QUIT command was encountered or the connection was refused from
3948 the particular host, or -1 if the connection was lost.
3952 Returns: > 0 message successfully started (reached DATA)
3953 = 0 QUIT read or end of file reached or call refused
3958 smtp_setup_msg(void)
3961 BOOL toomany = FALSE;
3962 BOOL discarded = FALSE;
3963 BOOL last_was_rej_mail = FALSE;
3964 BOOL last_was_rcpt = FALSE;
3965 rmark reset_point = store_mark();
3967 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3969 /* Reset for start of new message. We allow one RSET not to be counted as a
3970 nonmail command, for those MTAs that insist on sending it between every
3971 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3972 TLS between messages (an Exim client may do this if it has messages queued up
3973 for the host). Note: we do NOT reset AUTH at this point. */
3975 reset_point = smtp_reset(reset_point);
3976 message_ended = END_NOTSTARTED;
3978 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3980 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3981 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3982 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3984 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3987 if (lwr_receive_getc != NULL)
3989 /* This should have already happened, but if we've gotten confused,
3990 force a reset here. */
3991 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
3992 bdat_pop_receive_functions();
3995 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3997 had_command_sigterm = 0;
3998 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
4000 /* Batched SMTP is handled in a different function. */
4002 if (smtp_batched_input) return smtp_setup_batch_msg();
4004 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
4005 value. The values are 2 larger than the required yield of the function. */
4009 const uschar **argv;
4010 uschar *etrn_command;
4011 uschar *etrn_serialize_key;
4013 uschar *log_msg, *smtp_code;
4014 uschar *user_msg = NULL;
4015 uschar *recipient = NULL;
4016 uschar *hello = NULL;
4018 BOOL was_rej_mail = FALSE;
4019 BOOL was_rcpt = FALSE;
4020 void (*oldsignal)(int);
4022 int start, end, sender_domain, recipient_domain;
4025 uschar *orcpt = NULL;
4030 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
4031 if ( tls_in.active.sock >= 0
4033 && tls_in.certificate_verified
4034 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
4037 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
4039 for (auth_instance * au = auths; au; au = au->next)
4040 if (strcmpic(US"tls", au->driver_name) == 0)
4043 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4044 &user_msg, &log_msg)) != OK
4046 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4049 smtp_cmd_data = NULL;
4051 if (smtp_in_auth(au, &s, &ss) == OK)
4052 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
4054 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
4062 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
4063 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4064 US &off, sizeof(off));
4067 switch(smtp_read_command(
4068 #ifndef DISABLE_PIPE_CONNECT
4069 !fl.pipe_connect_acceptable,
4073 GETC_BUFFER_UNLIMITED))
4075 /* The AUTH command is not permitted to occur inside a transaction, and may
4076 occur successfully only once per connection. Actually, that isn't quite
4077 true. When TLS is started, all previous information about a connection must
4078 be discarded, so a new AUTH is permitted at that time.
4080 AUTH may only be used when it has been advertised. However, it seems that
4081 there are clients that send AUTH when it hasn't been advertised, some of
4082 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4083 So there's a get-out that allows this to happen.
4085 AUTH is initially labelled as a "nonmail command" so that one occurrence
4086 doesn't get counted. We change the label here so that multiple failing
4087 AUTHS will eventually hit the nonmail threshold. */
4091 authentication_failed = TRUE;
4092 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4094 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4096 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4097 US"AUTH command used when not advertised");
4100 if (sender_host_authenticated)
4102 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4103 US"already authenticated");
4108 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4109 US"not permitted in mail transaction");
4116 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4117 &user_msg, &log_msg)) != OK
4120 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4124 /* Find the name of the requested authentication mechanism. */
4127 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
4129 if (!isalnum(c) && c != '-' && c != '_')
4131 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4132 US"invalid character in authentication mechanism name");
4138 /* If not at the end of the line, we must be at white space. Terminate the
4139 name and move the pointer on to any data that may be present. */
4141 if (*smtp_cmd_data != 0)
4143 *smtp_cmd_data++ = 0;
4144 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4147 /* Search for an authentication mechanism which is configured for use
4148 as a server and which has been advertised (unless, sigh, allow_auth_
4149 unadvertised is set). */
4153 for (au = auths; au; au = au->next)
4154 if (strcmpic(s, au->public_name) == 0 && au->server &&
4155 (au->advertised || f.allow_auth_unadvertised))
4160 c = smtp_in_auth(au, &s, &ss);
4162 smtp_printf("%s\r\n", FALSE, s);
4164 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4165 au->name, host_and_ident(FALSE), ss);
4168 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4169 string_sprintf("%s authentication mechanism not supported", s));
4172 break; /* AUTH_CMD */
4174 /* The HELO/EHLO commands are permitted to appear in the middle of a
4175 session as well as at the beginning. They have the effect of a reset in
4176 addition to their other functions. Their absence at the start cannot be
4177 taken to be an error.
4181 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4182 or 502 failure replies MUST be returned as appropriate. The SMTP
4183 server MUST stay in the same state after transmitting these replies
4184 that it was in before the EHLO was received.
4186 Therefore, we do not do the reset until after checking the command for
4187 acceptability. This change was made for Exim release 4.11. Previously
4188 it did the reset first. */
4201 HELO_EHLO: /* Common code for HELO and EHLO */
4202 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4203 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4205 /* Reject the HELO if its argument was invalid or non-existent. A
4206 successful check causes the argument to be saved in malloc store. */
4208 if (!check_helo(smtp_cmd_data))
4210 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4212 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4213 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4214 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4215 string_printing(smtp_cmd_argument));
4217 if (++synprot_error_count > smtp_max_synprot_errors)
4219 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4220 "syntax or protocol errors (last command was \"%s\", %s)",
4221 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4222 string_from_gstring(s_connhad_log(NULL))
4230 /* If sender_host_unknown is true, we have got here via the -bs interface,
4231 not called from inetd. Otherwise, we are running an IP connection and the
4232 host address will be set. If the helo name is the primary name of this
4233 host and we haven't done a reverse lookup, force one now. If helo_required
4234 is set, ensure that the HELO name matches the actual host. If helo_verify
4235 is set, do the same check, but softly. */
4237 if (!f.sender_host_unknown)
4239 BOOL old_helo_verified = f.helo_verified;
4240 uschar *p = smtp_cmd_data;
4242 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4245 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4246 because otherwise the log can be confusing. */
4248 if ( !sender_host_name
4249 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4250 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4251 (void)host_name_lookup();
4253 /* Rebuild the fullhost info to include the HELO name (and the real name
4254 if it was looked up.) */
4256 host_build_sender_fullhost(); /* Rebuild */
4257 set_process_info("handling%s incoming connection from %s",
4258 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4260 /* Verify if configured. This doesn't give much security, but it does
4261 make some people happy to be able to do it. If helo_required is set,
4262 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4263 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4264 now obsolescent, since the verification can now be requested selectively
4267 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4268 if (fl.helo_required || fl.helo_verify)
4270 BOOL tempfail = !smtp_verify_helo();
4271 if (!f.helo_verified)
4273 if (fl.helo_required)
4275 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4276 tempfail? 451 : 550, hello);
4277 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4278 tempfail? "temporarily " : "",
4279 hello, sender_helo_name, host_and_ident(FALSE));
4280 f.helo_verified = old_helo_verified;
4281 break; /* End of HELO/EHLO processing */
4283 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4284 "helo_try_verify_hosts\n", hello);
4290 /* set up SPF context */
4291 spf_conn_init(sender_helo_name, sender_host_address);
4294 /* Apply an ACL check if one is defined; afterwards, recheck
4295 synchronization in case the client started sending in a delay. */
4298 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4299 &user_msg, &log_msg)) != OK)
4301 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4302 sender_helo_name = NULL;
4303 host_build_sender_fullhost(); /* Rebuild */
4306 #ifndef DISABLE_PIPE_CONNECT
4307 else if (!fl.pipe_connect_acceptable && !check_sync())
4309 else if (!check_sync())
4313 /* Generate an OK reply. The default string includes the ident if present,
4314 and also the IP address if present. Reflecting back the ident is intended
4315 as a deterrent to mail forgers. For maximum efficiency, and also because
4316 some broken systems expect each response to be in a single packet, arrange
4317 that the entire reply is sent in one write(). */
4319 fl.auth_advertised = FALSE;
4320 f.smtp_in_pipelining_advertised = FALSE;
4322 fl.tls_advertised = FALSE;
4324 fl.dsn_advertised = FALSE;
4326 fl.smtputf8_advertised = FALSE;
4329 smtp_code = US"250 "; /* Default response code plus space*/
4332 /* sender_host_name below will be tainted, so save on copy when we hit it */
4333 g = string_get_tainted(24, TRUE);
4334 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4336 smtp_active_hostname,
4337 sender_ident ? sender_ident : US"",
4338 sender_ident ? US" at " : US"",
4339 sender_host_name ? sender_host_name : sender_helo_name);
4341 if (sender_host_address)
4342 g = string_fmt_append(g, " [%s]", sender_host_address);
4345 /* A user-supplied EHLO greeting may not contain more than one line. Note
4346 that the code returned by smtp_message_code() includes the terminating
4347 whitespace character. */
4353 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4354 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4355 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4357 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4358 "newlines: message truncated: %s", string_printing(s));
4361 g = string_cat(NULL, s);
4364 g = string_catn(g, US"\r\n", 2);
4366 /* If we received EHLO, we must create a multiline response which includes
4367 the functions supported. */
4373 /* I'm not entirely happy with this, as an MTA is supposed to check
4374 that it has enough room to accept a message of maximum size before
4375 it sends this. However, there seems little point in not sending it.
4376 The actual size check happens later at MAIL FROM time. By postponing it
4377 till then, VRFY and EXPN can be used after EHLO when space is short. */
4379 if (thismessage_size_limit > 0)
4380 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4381 thismessage_size_limit);
4384 g = string_catn(g, smtp_code, 3);
4385 g = string_catn(g, US"-SIZE\r\n", 7);
4388 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4389 clean; if it has an 8-bit character in its hand, it just sends it. It
4390 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4391 However, some users want this option simply in order to stop MUAs
4392 mangling messages that contain top-bit-set characters. It is therefore
4393 provided as an option. */
4395 if (accept_8bitmime)
4397 g = string_catn(g, smtp_code, 3);
4398 g = string_catn(g, US"-8BITMIME\r\n", 11);
4401 /* Advertise DSN support if configured to do so. */
4402 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4404 g = string_catn(g, smtp_code, 3);
4405 g = string_catn(g, US"-DSN\r\n", 6);
4406 fl.dsn_advertised = TRUE;
4409 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4410 permitted to issue them; a check is made when any host actually tries. */
4414 g = string_catn(g, smtp_code, 3);
4415 g = string_catn(g, US"-ETRN\r\n", 7);
4419 g = string_catn(g, smtp_code, 3);
4420 g = string_catn(g, US"-VRFY\r\n", 7);
4424 g = string_catn(g, smtp_code, 3);
4425 g = string_catn(g, US"-EXPN\r\n", 7);
4428 /* Exim is quite happy with pipelining, so let the other end know that
4429 it is safe to use it, unless advertising is disabled. */
4431 if ( f.pipelining_enable
4432 && verify_check_host(&pipelining_advertise_hosts) == OK)
4434 g = string_catn(g, smtp_code, 3);
4435 g = string_catn(g, US"-PIPELINING\r\n", 13);
4436 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4437 f.smtp_in_pipelining_advertised = TRUE;
4439 #ifndef DISABLE_PIPE_CONNECT
4440 if (fl.pipe_connect_acceptable)
4442 f.smtp_in_early_pipe_advertised = TRUE;
4443 g = string_catn(g, smtp_code, 3);
4444 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4450 /* If any server authentication mechanisms are configured, advertise
4451 them if the current host is in auth_advertise_hosts. The problem with
4452 advertising always is that some clients then require users to
4453 authenticate (and aren't configurable otherwise) even though it may not
4454 be necessary (e.g. if the host is in host_accept_relay).
4456 RFC 2222 states that SASL mechanism names contain only upper case
4457 letters, so output the names in upper case, though we actually recognize
4458 them in either case in the AUTH command. */
4462 && !sender_host_authenticated
4464 && verify_check_host(&auth_advertise_hosts) == OK
4468 for (auth_instance * au = auths; au; au = au->next)
4470 au->advertised = FALSE;
4473 DEBUG(D_auth+D_expand) debug_printf_indent(
4474 "Evaluating advertise_condition for %s %s athenticator\n",
4475 au->name, au->public_name);
4476 if ( !au->advertise_condition
4477 || expand_check_condition(au->advertise_condition, au->name,
4484 g = string_catn(g, smtp_code, 3);
4485 g = string_catn(g, US"-AUTH", 5);
4487 fl.auth_advertised = TRUE;
4490 g = string_catn(g, US" ", 1);
4491 g = string_cat (g, au->public_name);
4492 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4493 au->advertised = TRUE;
4498 if (!first) g = string_catn(g, US"\r\n", 2);
4501 /* RFC 3030 CHUNKING */
4503 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4505 g = string_catn(g, smtp_code, 3);
4506 g = string_catn(g, US"-CHUNKING\r\n", 11);
4507 f.chunking_offered = TRUE;
4508 chunking_state = CHUNKING_OFFERED;
4511 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4512 if it has been included in the binary, and the host matches
4513 tls_advertise_hosts. We must *not* advertise if we are already in a
4514 secure connection. */
4517 if (tls_in.active.sock < 0 &&
4518 verify_check_host(&tls_advertise_hosts) != FAIL)
4520 g = string_catn(g, smtp_code, 3);
4521 g = string_catn(g, US"-STARTTLS\r\n", 11);
4522 fl.tls_advertised = TRUE;
4526 #ifndef DISABLE_PRDR
4527 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4530 g = string_catn(g, smtp_code, 3);
4531 g = string_catn(g, US"-PRDR\r\n", 7);
4536 if ( accept_8bitmime
4537 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4539 g = string_catn(g, smtp_code, 3);
4540 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4541 fl.smtputf8_advertised = TRUE;
4545 /* Finish off the multiline reply with one that is always available. */
4547 g = string_catn(g, smtp_code, 3);
4548 g = string_catn(g, US" HELP\r\n", 7);
4551 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4555 if (tls_in.active.sock >= 0)
4556 (void)tls_write(NULL, g->s, g->ptr,
4557 # ifndef DISABLE_PIPE_CONNECT
4558 fl.pipe_connect_acceptable && pipeline_connect_sends());
4566 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4572 (void) string_from_gstring(g);
4573 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4574 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4575 debug_printf("SMTP>> %s", g->s);
4577 fl.helo_seen = TRUE;
4579 /* Reset the protocol and the state, abandoning any previous message. */
4581 (sender_host_address ? protocols : protocols_local)
4583 ? pextend + (sender_host_authenticated ? pauthed : 0)
4585 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4587 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4588 reset_point = smtp_reset(reset_point);
4590 break; /* HELO/EHLO */
4593 /* The MAIL command requires an address as an operand. All we do
4594 here is to parse it for syntactic correctness. The form "<>" is
4595 a special case which converts into an empty string. The start/end
4596 pointers in the original are not used further for this address, as
4597 it is the canonical extracted address which is all that is kept. */
4601 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4602 was_rej_mail = TRUE; /* Reset if accepted */
4603 env_mail_type_t * mail_args; /* Sanity check & validate args */
4605 if (fl.helo_required && !fl.helo_seen)
4607 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4608 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4609 "HELO/EHLO given", host_and_ident(FALSE));
4615 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4616 US"sender already given");
4620 if (!*smtp_cmd_data)
4622 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4623 US"MAIL must have an address operand");
4627 /* Check to see if the limit for messages per connection would be
4628 exceeded by accepting further messages. */
4630 if (smtp_accept_max_per_connection > 0 &&
4631 smtp_mailcmd_count > smtp_accept_max_per_connection)
4633 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4634 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4635 "messages in one connection", host_and_ident(TRUE));
4639 /* Reset for start of message - even if this is going to fail, we
4640 obviously need to throw away any previous data. */
4642 cancel_cutthrough_connection(TRUE, US"MAIL received");
4643 reset_point = smtp_reset(reset_point);
4645 sender_data = recipient_data = NULL;
4647 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4649 if (fl.esmtp) for(;;)
4651 uschar *name, *value, *end;
4652 unsigned long int size;
4653 BOOL arg_error = FALSE;
4655 if (!extract_option(&name, &value)) break;
4657 for (mail_args = env_mail_type_list;
4658 mail_args->value != ENV_MAIL_OPT_NULL;
4661 if (strcmpic(name, mail_args->name) == 0)
4663 if (mail_args->need_value && strcmpic(value, US"") == 0)
4666 switch(mail_args->value)
4668 /* Handle SIZE= by reading the value. We don't do the check till later,
4669 in order to be able to log the sender address on failure. */
4670 case ENV_MAIL_OPT_SIZE:
4671 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4673 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4675 message_size = (int)size;
4681 /* If this session was initiated with EHLO and accept_8bitmime is set,
4682 Exim will have indicated that it supports the BODY=8BITMIME option. In
4683 fact, it does not support this according to the RFCs, in that it does not
4684 take any special action for forwarding messages containing 8-bit
4685 characters. That is why accept_8bitmime is not the default setting, but
4686 some sites want the action that is provided. We recognize both "8BITMIME"
4687 and "7BIT" as body types, but take no action. */
4688 case ENV_MAIL_OPT_BODY:
4689 if (accept_8bitmime) {
4690 if (strcmpic(value, US"8BITMIME") == 0)
4692 else if (strcmpic(value, US"7BIT") == 0)
4697 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4698 US"invalid data for BODY");
4701 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4707 /* Handle the two DSN options, but only if configured to do so (which
4708 will have caused "DSN" to be given in the EHLO response). The code itself
4709 is included only if configured in at build time. */
4711 case ENV_MAIL_OPT_RET:
4712 if (fl.dsn_advertised)
4714 /* Check if RET has already been set */
4717 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4718 US"RET can be specified once only");
4721 dsn_ret = strcmpic(value, US"HDRS") == 0
4723 : strcmpic(value, US"FULL") == 0
4726 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4727 /* Check for invalid invalid value, and exit with error */
4730 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4731 US"Value for RET is invalid");
4736 case ENV_MAIL_OPT_ENVID:
4737 if (fl.dsn_advertised)
4739 /* Check if the dsn envid has been already set */
4742 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4743 US"ENVID can be specified once only");
4746 dsn_envid = string_copy(value);
4747 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4751 /* Handle the AUTH extension. If the value given is not "<>" and either
4752 the ACL says "yes" or there is no ACL but the sending host is
4753 authenticated, we set it up as the authenticated sender. However, if the
4754 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4755 the condition is met. The value of AUTH is an xtext, which means that +,
4756 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4758 case ENV_MAIL_OPT_AUTH:
4759 if (Ustrcmp(value, "<>") != 0)
4764 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4766 /* Put back terminator overrides for error message */
4769 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4770 US"invalid data for AUTH");
4773 if (!acl_smtp_mailauth)
4775 ignore_msg = US"client not authenticated";
4776 rc = sender_host_authenticated ? OK : FAIL;
4780 ignore_msg = US"rejected by ACL";
4781 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4782 &user_msg, &log_msg);
4788 if (authenticated_by == NULL ||
4789 authenticated_by->mail_auth_condition == NULL ||
4790 expand_check_condition(authenticated_by->mail_auth_condition,
4791 authenticated_by->name, US"authenticator"))
4792 break; /* Accept the AUTH */
4794 ignore_msg = US"server_mail_auth_condition failed";
4795 if (authenticated_id != NULL)
4796 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4797 ignore_msg, authenticated_id);
4802 authenticated_sender = NULL;
4803 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4804 value, host_and_ident(TRUE), ignore_msg);
4807 /* Should only get DEFER or ERROR here. Put back terminator
4808 overrides for error message */
4813 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4820 #ifndef DISABLE_PRDR
4821 case ENV_MAIL_OPT_PRDR:
4823 prdr_requested = TRUE;
4828 case ENV_MAIL_OPT_UTF8:
4829 if (!fl.smtputf8_advertised)
4831 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4832 US"SMTPUTF8 used when not advertised");
4836 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4837 message_smtputf8 = allow_utf8_domains = TRUE;
4838 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4840 int old_pool = store_pool;
4841 store_pool = POOL_PERM;
4842 received_protocol = string_sprintf("utf8%s", received_protocol);
4843 store_pool = old_pool;
4848 /* No valid option. Stick back the terminator characters and break
4849 the loop. Do the name-terminator second as extract_option sets
4850 value==name when it found no equal-sign.
4851 An error for a malformed address will occur. */
4852 case ENV_MAIL_OPT_NULL:
4860 /* Break out of for loop if switch() had bad argument or
4861 when start of the email address is reached */
4862 if (arg_error) break;
4865 /* If we have passed the threshold for rate limiting, apply the current
4866 delay, and update it for next time, provided this is a limited host. */
4868 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4869 verify_check_host(&smtp_ratelimit_hosts) == OK)
4871 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4872 smtp_delay_mail/1000.0);
4873 millisleep((int)smtp_delay_mail);
4874 smtp_delay_mail *= smtp_rlm_factor;
4875 if (smtp_delay_mail > (double)smtp_rlm_limit)
4876 smtp_delay_mail = (double)smtp_rlm_limit;
4879 /* Now extract the address, first applying any SMTP-time rewriting. The
4880 TRUE flag allows "<>" as a sender address. */
4882 raw_sender = rewrite_existflags & rewrite_smtp
4883 /* deconst ok as smtp_cmd_data was not const */
4884 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4885 global_rewrite_rules)
4889 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4894 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4898 sender_address = raw_sender;
4900 /* If there is a configured size limit for mail, check that this message
4901 doesn't exceed it. The check is postponed to this point so that the sender
4904 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4906 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4907 log_write(L_size_reject,
4908 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4909 "message too big: size%s=%d max=%d",
4911 host_and_ident(TRUE),
4912 (message_size == INT_MAX)? ">" : "",
4914 thismessage_size_limit);
4915 sender_address = NULL;
4919 /* Check there is enough space on the disk unless configured not to.
4920 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4921 plus the current message - i.e. we accept the message only if it won't
4922 reduce the space below the threshold. Add 5000 to the size to allow for
4923 overheads such as the Received: line and storing of recipients, etc.
4924 By putting the check here, even when SIZE is not given, it allow VRFY
4925 and EXPN etc. to be used when space is short. */
4927 if (!receive_check_fs(
4928 smtp_check_spool_space && message_size >= 0
4929 ? message_size + 5000 : 0))
4931 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4932 sender_address = NULL;
4936 /* If sender_address is unqualified, reject it, unless this is a locally
4937 generated message, or the sending host or net is permitted to send
4938 unqualified addresses - typically local machines behaving as MUAs -
4939 in which case just qualify the address. The flag is set above at the start
4940 of the SMTP connection. */
4942 if (!sender_domain && *sender_address)
4943 if (f.allow_unqualified_sender)
4945 sender_domain = Ustrlen(sender_address) + 1;
4946 /* deconst ok as sender_address was not const */
4947 sender_address = US rewrite_address_qualify(sender_address, FALSE);
4948 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4953 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4955 log_write(L_smtp_syntax_error,
4956 LOG_MAIN|LOG_REJECT,
4957 "unqualified sender rejected: <%s> %s%s",
4959 host_and_ident(TRUE),
4961 sender_address = NULL;
4965 /* Apply an ACL check if one is defined, before responding. Afterwards,
4966 when pipelining is not advertised, do another sync check in case the ACL
4967 delayed and the client started sending in the meantime. */
4971 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4972 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4978 if (rc == OK || rc == DISCARD)
4980 BOOL more = pipeline_response();
4983 smtp_printf("%s%s%s", more, US"250 OK",
4984 #ifndef DISABLE_PRDR
4985 prdr_requested ? US", PRDR Requested" : US"",
4992 #ifndef DISABLE_PRDR
4994 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
4996 smtp_user_msg(US"250", user_msg);
4998 smtp_delay_rcpt = smtp_rlr_base;
4999 f.recipients_discarded = (rc == DISCARD);
5000 was_rej_mail = FALSE;
5004 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
5005 sender_address = NULL;
5010 /* The RCPT command requires an address as an operand. There may be any
5011 number of RCPT commands, specifying multiple recipients. We build them all
5012 into a data structure. The start/end values given by parse_extract_address
5013 are not used, as we keep only the extracted address. */
5017 /* We got really to many recipients. A check against configured
5018 limits is done later */
5019 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
5020 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
5022 was_rcpt = fl.rcpt_in_progress = TRUE;
5024 /* There must be a sender address; if the sender was rejected and
5025 pipelining was advertised, we assume the client was pipelining, and do not
5026 count this as a protocol error. Reset was_rej_mail so that further RCPTs
5027 get the same treatment. */
5029 if (sender_address == NULL)
5031 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
5033 smtp_printf("503 sender not yet given\r\n", FALSE);
5034 was_rej_mail = TRUE;
5038 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5039 US"sender not yet given");
5040 was_rcpt = FALSE; /* Not a valid RCPT */
5046 /* Check for an operand */
5048 if (smtp_cmd_data[0] == 0)
5050 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5051 US"RCPT must have an address operand");
5056 /* Set the DSN flags orcpt and dsn_flags from the session*/
5060 if (fl.esmtp) for(;;)
5062 uschar *name, *value;
5064 if (!extract_option(&name, &value))
5067 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5069 /* Check whether orcpt has been already set */
5072 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5073 US"ORCPT can be specified once only");
5076 orcpt = string_copy(value);
5077 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5080 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5082 /* Check if the notify flags have been already set */
5085 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5086 US"NOTIFY can be specified once only");
5089 if (strcmpic(value, US"NEVER") == 0)
5090 dsn_flags |= rf_notify_never;
5097 while (*pp != 0 && *pp != ',') pp++;
5098 if (*pp == ',') *pp++ = 0;
5099 if (strcmpic(p, US"SUCCESS") == 0)
5101 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5102 dsn_flags |= rf_notify_success;
5104 else if (strcmpic(p, US"FAILURE") == 0)
5106 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5107 dsn_flags |= rf_notify_failure;
5109 else if (strcmpic(p, US"DELAY") == 0)
5111 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5112 dsn_flags |= rf_notify_delay;
5116 /* Catch any strange values */
5117 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5118 US"Invalid value for NOTIFY parameter");
5123 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5127 /* Unknown option. Stick back the terminator characters and break
5128 the loop. An error for a malformed address will occur. */
5132 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5139 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5140 as a recipient address */
5142 recipient = rewrite_existflags & rewrite_smtp
5143 /* deconst ok as smtp_cmd_data was not const */
5144 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5145 global_rewrite_rules)
5148 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5149 &recipient_domain, FALSE)))
5151 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5156 /* If the recipient address is unqualified, reject it, unless this is a
5157 locally generated message. However, unqualified addresses are permitted
5158 from a configured list of hosts and nets - typically when behaving as
5159 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5160 really. The flag is set at the start of the SMTP connection.
5162 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5163 assumed this meant "reserved local part", but the revision of RFC 821 and
5164 friends now makes it absolutely clear that it means *mailbox*. Consequently
5165 we must always qualify this address, regardless. */
5167 if (!recipient_domain)
5168 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5175 /* Check maximum allowed */
5177 if (rcpt_count+1 < 0 || rcpt_count > recipients_max && recipients_max > 0)
5179 if (recipients_max_reject)
5182 smtp_printf("552 too many recipients\r\n", FALSE);
5184 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5185 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5190 smtp_printf("452 too many recipients\r\n", FALSE);
5192 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5193 "temporarily rejected: sender=<%s> %s", sender_address,
5194 host_and_ident(TRUE));
5201 /* If we have passed the threshold for rate limiting, apply the current
5202 delay, and update it for next time, provided this is a limited host. */
5204 if (rcpt_count > smtp_rlr_threshold &&
5205 verify_check_host(&smtp_ratelimit_hosts) == OK)
5207 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5208 smtp_delay_rcpt/1000.0);
5209 millisleep((int)smtp_delay_rcpt);
5210 smtp_delay_rcpt *= smtp_rlr_factor;
5211 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5212 smtp_delay_rcpt = (double)smtp_rlr_limit;
5215 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5216 for them. Otherwise, check the access control list for this recipient. As
5217 there may be a delay in this, re-check for a synchronization error
5218 afterwards, unless pipelining was advertised. */
5220 if (f.recipients_discarded)
5223 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5225 && !f.smtp_in_pipelining_advertised && !check_sync())
5228 /* The ACL was happy */
5232 BOOL more = pipeline_response();
5235 smtp_user_msg(US"250", user_msg);
5237 smtp_printf("250 Accepted\r\n", more);
5238 receive_add_recipient(recipient, -1);
5240 /* Set the dsn flags in the recipients_list */
5241 recipients_list[recipients_count-1].orcpt = orcpt;
5242 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5244 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5245 recipients_list[recipients_count-1].orcpt,
5246 recipients_list[recipients_count-1].dsn_flags); */
5249 /* The recipient was discarded */
5251 else if (rc == DISCARD)
5254 smtp_user_msg(US"250", user_msg);
5256 smtp_printf("250 Accepted\r\n", FALSE);
5259 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5260 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5261 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5262 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5263 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5266 /* Either the ACL failed the address, or it was deferred. */
5270 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5271 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5276 /* The DATA command is legal only if it follows successful MAIL FROM
5277 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5278 not counted as a protocol error if it follows RCPT (which must have been
5279 rejected if there are no recipients.) This function is complete when a
5280 valid DATA command is encountered.
5282 Note concerning the code used: RFC 2821 says this:
5284 - If there was no MAIL, or no RCPT, command, or all such commands
5285 were rejected, the server MAY return a "command out of sequence"
5286 (503) or "no valid recipients" (554) reply in response to the
5289 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5290 because it is the same whether pipelining is in use or not.
5292 If all the RCPT commands that precede DATA provoked the same error message
5293 (often indicating some kind of system error), it is helpful to include it
5294 with the DATA rejection (an idea suggested by Tony Finch). */
5301 if (chunking_state != CHUNKING_OFFERED)
5303 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5304 US"BDAT command used when CHUNKING not advertised");
5308 /* grab size, endmarker */
5310 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5312 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5313 US"missing size for BDAT command");
5316 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5317 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5318 chunking_data_left = chunking_datasize;
5319 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5320 (int)chunking_state, chunking_data_left);
5322 f.bdat_readers_wanted = TRUE;
5331 f.bdat_readers_wanted = FALSE;
5333 DATA_BDAT: /* Common code for DATA and BDAT */
5334 #ifndef DISABLE_PIPE_CONNECT
5335 fl.pipe_connect_acceptable = FALSE;
5337 if (!discarded && recipients_count <= 0)
5339 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5341 uschar *code = US"503";
5342 int len = Ustrlen(rcpt_smtp_response);
5343 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5345 /* Responses from smtp_printf() will have \r\n on the end */
5346 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5347 rcpt_smtp_response[len-2] = 0;
5348 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5350 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5351 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5352 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5354 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5355 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5356 ? US"valid RCPT command must precede DATA"
5357 : US"valid RCPT command must precede BDAT");
5359 if (chunking_state > CHUNKING_OFFERED)
5361 bdat_push_receive_functions();
5367 if (toomany && recipients_max_reject)
5369 sender_address = NULL; /* This will allow a new MAIL without RSET */
5370 sender_address_unrewritten = NULL;
5371 smtp_printf("554 Too many recipients\r\n", FALSE);
5375 if (chunking_state > CHUNKING_OFFERED)
5376 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5379 /* If there is an ACL, re-check the synchronization afterwards, since the
5380 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5381 to get the DATA command sent. */
5383 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5387 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5388 f.enable_dollar_recipients = TRUE;
5389 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5391 f.enable_dollar_recipients = FALSE;
5392 if (rc == OK && !check_sync())
5396 { /* Either the ACL failed the address, or it was deferred. */
5397 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5403 smtp_user_msg(US"354", user_msg);
5406 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5409 if (f.bdat_readers_wanted)
5410 bdat_push_receive_functions();
5413 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5414 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5415 US &on, sizeof(on));
5418 message_ended = END_NOTENDED; /* Indicate in middle of data */
5429 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5430 &start, &end, &recipient_domain, FALSE)))
5432 smtp_printf("501 %s\r\n", FALSE, errmess);
5436 if (!recipient_domain)
5437 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5441 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5442 &user_msg, &log_msg)) != OK)
5443 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5447 address_item * addr = deliver_make_addr(address, FALSE);
5449 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5450 -1, -1, NULL, NULL, NULL))
5453 s = string_sprintf("250 <%s> is deliverable", address);
5457 s = (addr->user_message != NULL)?
5458 string_sprintf("451 <%s> %s", address, addr->user_message) :
5459 string_sprintf("451 Cannot resolve <%s> at this time", address);
5463 s = (addr->user_message != NULL)?
5464 string_sprintf("550 <%s> %s", address, addr->user_message) :
5465 string_sprintf("550 <%s> is not deliverable", address);
5466 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5467 smtp_cmd_argument, host_and_ident(TRUE));
5471 smtp_printf("%s\r\n", FALSE, s);
5479 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5481 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5484 BOOL save_log_testing_mode = f.log_testing_mode;
5485 f.address_test_mode = f.log_testing_mode = TRUE;
5486 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5487 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5489 f.address_test_mode = FALSE;
5490 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5499 if (!fl.tls_advertised)
5501 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5502 US"STARTTLS command used when not advertised");
5506 /* Apply an ACL check if one is defined */
5508 if ( acl_smtp_starttls
5509 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5510 &user_msg, &log_msg)) != OK
5513 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5517 /* RFC 2487 is not clear on when this command may be sent, though it
5518 does state that all information previously obtained from the client
5519 must be discarded if a TLS session is started. It seems reasonable to
5520 do an implied RSET when STARTTLS is received. */
5522 incomplete_transaction_log(US"STARTTLS");
5523 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5524 reset_point = smtp_reset(reset_point);
5526 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5528 /* There's an attack where more data is read in past the STARTTLS command
5529 before TLS is negotiated, then assumed to be part of the secure session
5530 when used afterwards; we use segregated input buffers, so are not
5531 vulnerable, but we want to note when it happens and, for sheer paranoia,
5532 ensure that the buffer is "wiped".
5533 Pipelining sync checks will normally have protected us too, unless disabled
5534 by configuration. */
5536 if (receive_smtp_buffered())
5539 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5540 if (tls_in.active.sock < 0)
5541 smtp_inend = smtp_inptr = smtp_inbuffer;
5542 /* and if TLS is already active, tls_server_start() should fail */
5545 /* There is nothing we value in the input buffer and if TLS is successfully
5546 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5547 fresh content into it. The buffer contains arbitrary content from an
5548 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5549 It seems safest to just wipe away the content rather than leave it as a
5550 target to jump to. */
5552 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5554 /* Attempt to start up a TLS session, and if successful, discard all
5555 knowledge that was obtained previously. At least, that's what the RFC says,
5556 and that's what happens by default. However, in order to work round YAEB,
5557 there is an option to remember the esmtp state. Sigh.
5559 We must allow for an extra EHLO command and an extra AUTH command after
5560 STARTTLS that don't add to the nonmail command count. */
5563 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5565 if (!tls_remember_esmtp)
5566 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5567 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5568 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5569 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5570 if (sender_helo_name)
5572 sender_helo_name = NULL;
5573 host_build_sender_fullhost(); /* Rebuild */
5574 set_process_info("handling incoming TLS connection from %s",
5575 host_and_ident(FALSE));
5578 (sender_host_address ? protocols : protocols_local)
5580 ? pextend + (sender_host_authenticated ? pauthed : 0)
5582 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5585 sender_host_auth_pubname = sender_host_authenticated = NULL;
5586 authenticated_id = NULL;
5587 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5588 DEBUG(D_tls) debug_printf("TLS active\n");
5589 break; /* Successful STARTTLS */
5592 (void) smtp_log_tls_fail(s);
5594 /* Some local configuration problem was discovered before actually trying
5595 to do a TLS handshake; give a temporary error. */
5599 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5603 /* Hard failure. Reject everything except QUIT or closed connection. One
5604 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5605 set, but we must still reject all incoming commands. Another is a handshake
5606 failure - and there may some encrypted data still in the pipe to us, which we
5607 see as garbage commands. */
5609 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5610 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5613 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5614 smtp_get_connection_info());
5615 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5619 /* It is perhaps arguable as to which exit ACL should be called here,
5620 but as it is probably a situation that almost never arises, it
5621 probably doesn't matter. We choose to call the real QUIT ACL, which in
5622 some sense is perhaps "right". */
5627 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5628 &log_msg)) == ERROR))
5629 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5632 smtp_respond(US"221", 3, TRUE, user_msg);
5634 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5635 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5636 smtp_get_connection_info());
5641 smtp_printf("554 Security failure\r\n", FALSE);
5644 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5649 /* The ACL for QUIT is provided for gathering statistical information or
5650 similar; it does not affect the response code, but it can supply a custom
5654 smtp_quit_handler(&user_msg, &log_msg);
5660 smtp_rset_handler();
5661 cancel_cutthrough_connection(TRUE, US"RSET received");
5662 reset_point = smtp_reset(reset_point);
5669 smtp_printf("250 OK\r\n", FALSE);
5673 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5674 used, a check will be done for permitted hosts. Show STARTTLS only if not
5675 already in a TLS session and if it would be advertised in the EHLO
5680 smtp_printf("214-Commands supported:\r\n", TRUE);
5684 Ustrcat(buffer, US" AUTH");
5686 if (tls_in.active.sock < 0 &&
5687 verify_check_host(&tls_advertise_hosts) != FAIL)
5688 Ustrcat(buffer, US" STARTTLS");
5690 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5691 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5692 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5693 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5694 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5695 smtp_printf("214%s\r\n", FALSE, buffer);
5701 incomplete_transaction_log(US"connection lost");
5702 smtp_notquit_exit(US"connection-lost", US"421",
5703 US"%s lost input connection", smtp_active_hostname);
5705 /* Don't log by default unless in the middle of a message, as some mailers
5706 just drop the call rather than sending QUIT, and it clutters up the logs.
5709 if (sender_address || recipients_count > 0)
5710 log_write(L_lost_incoming_connection, LOG_MAIN,
5711 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5712 f.sender_host_unknown ? "EOF" : "disconnection",
5713 f.tcp_in_fastopen_logged
5716 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5718 host_and_ident(FALSE), smtp_read_error,
5719 string_timesince(&smtp_connection_start)
5723 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5724 smtp_get_connection_info(),
5725 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5727 string_timesince(&smtp_connection_start)
5738 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5739 US"ETRN is not permitted inside a transaction");
5743 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5744 host_and_ident(FALSE));
5746 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5747 &user_msg, &log_msg)) != OK)
5749 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5753 /* Compute the serialization key for this command. */
5755 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5757 /* If a command has been specified for running as a result of ETRN, we
5758 permit any argument to ETRN. If not, only the # standard form is permitted,
5759 since that is strictly the only kind of ETRN that can be implemented
5760 according to the RFC. */
5762 if (smtp_etrn_command)
5766 etrn_command = smtp_etrn_command;
5767 deliver_domain = smtp_cmd_data;
5768 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5769 US"ETRN processing", &error);
5770 deliver_domain = NULL;
5773 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5775 smtp_printf("458 Internal failure\r\n", FALSE);
5780 /* Else set up to call Exim with the -R option. */
5784 if (*smtp_cmd_data++ != '#')
5786 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5787 US"argument must begin with #");
5790 etrn_command = US"exim -R";
5791 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5792 *queue_name ? 4 : 2,
5793 US"-R", smtp_cmd_data,
5794 US"-MCG", queue_name);
5797 /* If we are host-testing, don't actually do anything. */
5803 debug_printf("ETRN command is: %s\n", etrn_command);
5804 debug_printf("ETRN command execution skipped\n");
5806 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5807 else smtp_user_msg(US"250", user_msg);
5812 /* If ETRN queue runs are to be serialized, check the database to
5813 ensure one isn't already running. */
5815 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5817 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5821 /* Fork a child process and run the command. We don't want to have to
5822 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5823 forking. It should be set that way anyway for external incoming SMTP,
5824 but we save and restore to be tidy. If serialization is required, we
5825 actually run the command in yet another process, so we can wait for it
5826 to complete and then remove the serialization lock. */
5828 oldsignal = signal(SIGCHLD, SIG_IGN);
5830 if ((pid = exim_fork(US"etrn-command")) == 0)
5832 smtp_input = FALSE; /* This process is not associated with the */
5833 (void)fclose(smtp_in); /* SMTP call any more. */
5834 (void)fclose(smtp_out);
5836 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5838 /* If not serializing, do the exec right away. Otherwise, fork down
5839 into another process. */
5841 if ( !smtp_etrn_serialize
5842 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5844 DEBUG(D_exec) debug_print_argv(argv);
5845 exim_nullstd(); /* Ensure std{in,out,err} exist */
5846 execv(CS argv[0], (char *const *)argv);
5847 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5848 etrn_command, strerror(errno));
5849 _exit(EXIT_FAILURE); /* paranoia */
5852 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5853 is, we are in the first subprocess, after forking again. All we can do
5854 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5855 complete, before removing the serialization. */
5858 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5859 "failed: %s", strerror(errno));
5863 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5865 (void)wait(&status);
5866 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5870 enq_end(etrn_serialize_key);
5871 exim_underbar_exit(EXIT_SUCCESS);
5874 /* Back in the top level SMTP process. Check that we started a subprocess
5875 and restore the signal state. */
5879 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5881 smtp_printf("458 Unable to fork process\r\n", FALSE);
5882 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5886 smtp_printf("250 OK\r\n", FALSE);
5888 smtp_user_msg(US"250", user_msg);
5890 signal(SIGCHLD, oldsignal);
5895 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5896 US"unexpected argument data");
5900 /* This currently happens only for NULLs, but could be extended. */
5903 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5904 US"NUL character(s) present (shown as '?')");
5905 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5912 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5913 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5914 c = smtp_inend - smtp_inptr;
5915 if (c > 150) c = 150; /* limit logged amount */
5917 incomplete_transaction_log(US"sync failure");
5918 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5919 "(next input sent too soon: pipelining was%s advertised): "
5920 "rejected \"%s\" %s next input=\"%s\"",
5921 f.smtp_in_pipelining_advertised ? "" : " not",
5922 smtp_cmd_buffer, host_and_ident(TRUE),
5923 string_printing(smtp_inptr));
5924 smtp_notquit_exit(US"synchronization-error", US"554",
5925 US"SMTP synchronization error");
5926 done = 1; /* Pretend eof - drops connection */
5930 case TOO_MANY_NONMAIL_CMD:
5931 s = smtp_cmd_buffer;
5932 while (*s != 0 && !isspace(*s)) s++;
5933 incomplete_transaction_log(US"too many non-mail commands");
5934 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5935 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5936 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5937 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5938 done = 1; /* Pretend eof - drops connection */
5941 #ifdef SUPPORT_PROXY
5942 case PROXY_FAIL_IGNORE_CMD:
5943 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5948 if (unknown_command_count++ >= smtp_max_unknown_commands)
5950 log_write(L_smtp_syntax_error, LOG_MAIN,
5951 "SMTP syntax error in \"%s\" %s %s",
5952 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5953 US"unrecognized command");
5954 incomplete_transaction_log(US"unrecognized command");
5955 smtp_notquit_exit(US"bad-commands", US"500",
5956 US"Too many unrecognized commands");
5958 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5959 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5960 string_printing(smtp_cmd_buffer));
5963 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5964 US"unrecognized command");
5968 /* This label is used by goto's inside loops that want to break out to
5969 the end of the command-processing loop. */
5972 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5973 last_was_rcpt = was_rcpt; /* protocol error handling */
5977 return done - 2; /* Convert yield values */
5983 authres_smtpauth(gstring * g)
5985 if (!sender_host_authenticated)
5988 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
5990 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
5991 g = authenticated_id
5992 ? string_append(g, 2, US") x509.auth=", authenticated_id)
5993 : string_cat(g, US") reason=x509.auth");
5995 g = authenticated_id
5996 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
5997 : string_cat(g, US", no id saved)");
5999 if (authenticated_sender)
6000 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
6008 /* End of smtp_in.c */