1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* Copyright (c) The Exim Maintainers 2020 */
7 /* See the file NOTICE for conditions of use and distribution. */
9 /* Functions for handling an incoming SMTP call. */
16 /* Initialize for TCP wrappers if so configured. It appears that the macro
17 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
18 including that header, and restore its value afterwards. */
20 #ifdef USE_TCP_WRAPPERS
23 #define EXIM_HAVE_IPV6
29 #define HAVE_IPV6 TRUE
32 int allow_severity = LOG_INFO;
33 int deny_severity = LOG_NOTICE;
34 uschar *tcp_wrappers_name;
38 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
39 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
40 commands that accept arguments, and this in particular applies to AUTH, where
41 the data can be quite long. More recently this value was 2048 in Exim;
42 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
43 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
44 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
45 we need room to handle large base64-encoded AUTHs for GSSAPI.
48 #define SMTP_CMD_BUFFER_SIZE 16384
50 /* Size of buffer for reading SMTP incoming packets */
52 #define IN_BUFFER_SIZE 8192
54 /* Structure for SMTP command list */
61 short int is_mail_cmd;
64 /* Codes for identifying commands. We order them so that those that come first
65 are those for which synchronization is always required. Checking this can help
69 /* These commands are required to be synchronized, i.e. to be the last in a
70 block of commands when pipelining. */
72 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
73 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
74 ETRN_CMD, /* This by analogy with TURN from the RFC */
75 STARTTLS_CMD, /* Required by the STARTTLS RFC */
76 TLS_AUTH_CMD, /* auto-command at start of SSL */
78 /* This is a dummy to identify the non-sync commands when pipelining */
80 NON_SYNC_CMD_PIPELINING,
82 /* These commands need not be synchronized when pipelining */
84 MAIL_CMD, RCPT_CMD, RSET_CMD,
86 /* This is a dummy to identify the non-sync commands when not pipelining */
88 NON_SYNC_CMD_NON_PIPELINING,
90 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
91 processed the message is sent using a series of BDAT commands"
92 implies that BDAT should be synchronized. However, we see Google, at least,
93 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
94 processing of the RCPT response(s). We shall do the same, and not require
95 synch for BDAT. Worse, as the chunk may (very likely will) follow the
96 command-header in the same packet we cannot do the usual "is there any
97 follow-on data after the command line" even for non-pipeline mode.
98 So we'll need an explicit check after reading the expected chunk amount
99 when non-pipe, before sending the ACK. */
103 /* I have been unable to find a statement about the use of pipelining
104 with AUTH, so to be on the safe side it is here, though I kind of feel
105 it should be up there with the synchronized commands. */
109 /* I'm not sure about these, but I don't think they matter. */
114 PROXY_FAIL_IGNORE_CMD,
117 /* These are specials that don't correspond to actual commands */
119 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
120 TOO_MANY_NONMAIL_CMD };
123 /* This is a convenience macro for adding the identity of an SMTP command
124 to the circular buffer that holds a list of the last n received. */
127 smtp_connection_had[smtp_ch_index++] = n; \
128 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
131 /*************************************************
132 * Local static variables *
133 *************************************************/
136 BOOL auth_advertised :1;
138 BOOL tls_advertised :1;
140 BOOL dsn_advertised :1;
142 BOOL helo_required :1;
145 BOOL helo_accept_junk :1;
146 #ifndef DISABLE_PIPE_CONNECT
147 BOOL pipe_connect_acceptable :1;
149 BOOL rcpt_smtp_response_same :1;
150 BOOL rcpt_in_progress :1;
151 BOOL smtp_exit_function_called :1;
153 BOOL smtputf8_advertised :1;
156 .helo_required = FALSE,
157 .helo_verify = FALSE,
158 .smtp_exit_function_called = FALSE,
161 static auth_instance *authenticated_by;
162 static int count_nonmail;
163 static int nonmail_command_count;
164 static int synprot_error_count;
165 static int unknown_command_count;
166 static int sync_cmd_limit;
167 static int smtp_write_error = 0;
169 static uschar *rcpt_smtp_response;
170 static uschar *smtp_data_buffer;
171 static uschar *smtp_cmd_data;
173 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
174 final fields of all except AUTH are forced TRUE at the start of a new message
175 setup, to allow one of each between messages that is not counted as a nonmail
176 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
177 allow a new EHLO after starting up TLS.
179 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
180 counted. However, the flag is changed when AUTH is received, so that multiple
181 failing AUTHs will eventually hit the limit. After a successful AUTH, another
182 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
183 forced TRUE, to allow for the re-authentication that can happen at that point.
185 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
186 count of non-mail commands and possibly provoke an error.
188 tls_auth is a pseudo-command, never expected in input. It is activated
189 on TLS startup and looks for a tls authenticator. */
191 static smtp_cmd_list cmd_list[] = {
192 /* name len cmd has_arg is_mail_cmd */
194 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
195 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
196 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
197 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
199 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
200 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
203 /* If you change anything above here, also fix the definitions below. */
205 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
206 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
207 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
208 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
209 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
210 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
211 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
212 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
213 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
214 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
217 static smtp_cmd_list *cmd_list_end =
218 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
220 #define CMD_LIST_RSET 0
221 #define CMD_LIST_HELO 1
222 #define CMD_LIST_EHLO 2
223 #define CMD_LIST_AUTH 3
224 #define CMD_LIST_STARTTLS 4
225 #define CMD_LIST_TLS_AUTH 5
227 /* This list of names is used for performing the smtp_no_mail logging action.
228 It must be kept in step with the SCH_xxx enumerations. */
230 static uschar *smtp_names[] =
232 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
233 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
234 US"STARTTLS", US"VRFY" };
236 static uschar *protocols_local[] = {
237 US"local-smtp", /* HELO */
238 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
239 US"local-esmtp", /* EHLO */
240 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
241 US"local-esmtpa", /* EHLO->AUTH */
242 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
244 static uschar *protocols[] = {
246 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
247 US"esmtp", /* EHLO */
248 US"esmtps", /* EHLO->STARTTLS->EHLO */
249 US"esmtpa", /* EHLO->AUTH */
250 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
255 #define pcrpted 1 /* added to pextend or pnormal */
256 #define pauthed 2 /* added to pextend */
258 /* Sanity check and validate optional args to MAIL FROM: envelope */
261 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
265 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
271 uschar * name; /* option requested during MAIL cmd */
272 int value; /* enum type */
273 BOOL need_value; /* TRUE requires value (name=value pair format)
274 FALSE is a singleton */
276 static env_mail_type_t env_mail_type_list[] = {
277 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
278 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
279 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
281 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
283 { US"RET", ENV_MAIL_OPT_RET, TRUE },
284 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
286 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
288 /* keep this the last entry */
289 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
292 /* When reading SMTP from a remote host, we have to use our own versions of the
293 C input-reading functions, in order to be able to flush the SMTP output only
294 when about to read more data from the socket. This is the only way to get
295 optimal performance when the client is using pipelining. Flushing for every
296 command causes a separate packet and reply packet each time; saving all the
297 responses up (when pipelining) combines them into one packet and one response.
299 For simplicity, these functions are used for *all* SMTP input, not only when
300 receiving over a socket. However, after setting up a secure socket (SSL), input
301 is read via the OpenSSL library, and another set of functions is used instead
304 These functions are set in the receive_getc etc. variables and called with the
305 same interface as the C functions. However, since there can only ever be
306 one incoming SMTP call, we just use a single buffer and flags. There is no need
307 to implement a complicated private FILE-like structure.*/
309 static uschar *smtp_inbuffer;
310 static uschar *smtp_inptr;
311 static uschar *smtp_inend;
312 static int smtp_had_eof;
313 static int smtp_had_error;
316 /* forward declarations */
317 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
318 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
319 static void smtp_quit_handler(uschar **, uschar **);
320 static void smtp_rset_handler(void);
322 /*************************************************
323 * Recheck synchronization *
324 *************************************************/
326 /* Synchronization checks can never be perfect because a packet may be on its
327 way but not arrived when the check is done. Normally, the checks happen when
328 commands are read: Exim ensures that there is no more input in the input buffer.
329 In normal cases, the response to the command will be fast, and there is no
332 However, for some commands an ACL is run, and that can include delays. In those
333 cases, it is useful to do another check on the input just before sending the
334 response. This also applies at the start of a connection. This function does
335 that check by means of the select() function, as long as the facility is not
336 disabled or inappropriate. A failure of select() is ignored.
338 When there is unwanted input, we read it so that it appears in the log of the
342 Returns: TRUE if all is well; FALSE if there is input pending
346 wouldblock_reading(void)
350 struct timeval tzero;
353 if (tls_in.active.sock >= 0)
354 return !tls_could_read();
357 if (smtp_inptr < smtp_inend)
360 fd = fileno(smtp_in);
365 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
367 if (rc <= 0) return TRUE; /* Not ready to read */
368 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
369 if (rc < 0) return TRUE; /* End of file or error */
378 if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket)
381 return wouldblock_reading();
385 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
386 a reponse with the one following. */
389 pipeline_response(void)
391 if ( !smtp_enforce_sync || !sender_host_address
392 || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised)
395 if (wouldblock_reading()) return FALSE;
396 f.smtp_in_pipelining_used = TRUE;
401 #ifndef DISABLE_PIPE_CONNECT
403 pipeline_connect_sends(void)
405 if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable)
408 if (wouldblock_reading()) return FALSE;
409 f.smtp_in_early_pipe_used = TRUE;
414 /*************************************************
415 * Log incomplete transactions *
416 *************************************************/
418 /* This function is called after a transaction has been aborted by RSET, QUIT,
419 connection drops or other errors. It logs the envelope information received
420 so far in order to preserve address verification attempts.
422 Argument: string to indicate what aborted the transaction
427 incomplete_transaction_log(uschar *what)
429 if (!sender_address /* No transaction in progress */
430 || !LOGGING(smtp_incomplete_transaction))
433 /* Build list of recipients for logging */
435 if (recipients_count > 0)
437 raw_recipients = store_get(recipients_count * sizeof(uschar *), FALSE);
438 for (int i = 0; i < recipients_count; i++)
439 raw_recipients[i] = recipients_list[i].address;
440 raw_recipients_count = recipients_count;
443 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
444 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
451 smtp_command_timeout_exit(void)
453 log_write(L_lost_incoming_connection,
454 LOG_MAIN, "SMTP command timeout on%s connection from %s",
455 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
456 if (smtp_batched_input)
457 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
458 smtp_notquit_exit(US"command-timeout", US"421",
459 US"%s: SMTP command timeout - closing connection",
460 smtp_active_hostname);
461 exim_exit(EXIT_FAILURE);
465 smtp_command_sigterm_exit(void)
467 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
468 if (smtp_batched_input)
469 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
470 smtp_notquit_exit(US"signal-exit", US"421",
471 US"%s: Service not available - closing connection", smtp_active_hostname);
472 exim_exit(EXIT_FAILURE);
476 smtp_data_timeout_exit(void)
478 log_write(L_lost_incoming_connection,
479 LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>",
480 sender_fullhost ? sender_fullhost : US"local process", sender_address);
481 receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout");
482 /* Does not return */
486 smtp_data_sigint_exit(void)
488 log_write(0, LOG_MAIN, "%s closed after %s",
489 smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT");
490 receive_bomb_out(US"signal-exit",
491 US"Service not available - SIGTERM or SIGINT received");
492 /* Does not return */
497 /* Refill the buffer, and notify DKIM verification code.
498 Return false for error or EOF.
502 smtp_refill(unsigned lim)
505 if (!smtp_out) return FALSE;
507 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
509 /* Limit amount read, so non-message data is not fed to DKIM.
510 Take care to not touch the safety NUL at the end of the buffer. */
512 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim));
514 if (smtp_receive_timeout > 0) ALARM_CLR(0);
517 /* Must put the error text in fixed store, because this might be during
518 header reading, where it releases unused store above the header. */
521 if (had_command_timeout) /* set by signal handler */
522 smtp_command_timeout_exit(); /* does not return */
523 if (had_command_sigterm)
524 smtp_command_sigterm_exit();
525 if (had_data_timeout)
526 smtp_data_timeout_exit();
528 smtp_data_sigint_exit();
530 smtp_had_error = save_errno;
531 smtp_read_error = string_copy_perm(
532 string_sprintf(" (error: %s)", strerror(save_errno)), FALSE);
539 dkim_exim_verify_feed(smtp_inbuffer, rc);
541 smtp_inend = smtp_inbuffer + rc;
542 smtp_inptr = smtp_inbuffer;
546 /*************************************************
547 * SMTP version of getc() *
548 *************************************************/
550 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
551 it flushes the output, and refills the buffer, with a timeout. The signal
552 handler is set appropriately by the calling function. This function is not used
553 after a connection has negotiated itself into an TLS/SSL state.
555 Arguments: lim Maximum amount to read/buffer
556 Returns: the next character or EOF
560 smtp_getc(unsigned lim)
562 if (smtp_inptr >= smtp_inend)
563 if (!smtp_refill(lim))
565 return *smtp_inptr++;
569 smtp_getbuf(unsigned * len)
574 if (smtp_inptr >= smtp_inend)
575 if (!smtp_refill(*len))
576 { *len = 0; return NULL; }
578 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
589 int n = smtp_inend - smtp_inptr;
591 dkim_exim_verify_feed(smtp_inptr, n);
596 /* Forward declarations */
597 static inline void bdat_push_receive_functions(void);
598 static inline void bdat_pop_receive_functions(void);
601 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
602 previous BDAT chunk and getting new ones when we run out. Uses the
603 underlying smtp_getc or tls_getc both for that and for getting the
604 (buffered) data byte. EOD signals (an expected) no further data.
605 ERR signals a protocol error, and EOF a closed input stream.
607 Called from read_bdat_smtp() in receive.c for the message body, but also
608 by the headers read loop in receive_msg(); manipulates chunking_state
609 to handle the BDAT command/response.
610 Placed here due to the correlation with the above smtp_getc(), which it wraps,
611 and also by the need to do smtp command/response handling.
613 Arguments: lim (ignored)
614 Returns: the next character or ERR, EOD or EOF
618 bdat_getc(unsigned lim)
620 uschar * user_msg = NULL;
629 if (chunking_data_left > 0)
630 return lwr_receive_getc(chunking_data_left--);
632 bdat_pop_receive_functions();
634 dkim_save = dkim_collect_input;
635 dkim_collect_input = 0;
638 /* Unless PIPELINING was offered, there should be no next command
639 until after we ack that chunk */
641 if (!f.smtp_in_pipelining_advertised && !check_sync())
643 unsigned n = smtp_inend - smtp_inptr;
646 incomplete_transaction_log(US"sync failure");
647 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
648 "(next input sent too soon: pipelining was not advertised): "
649 "rejected \"%s\" %s next input=\"%s\"%s",
650 smtp_cmd_buffer, host_and_ident(TRUE),
651 string_printing(string_copyn(smtp_inptr, n)),
652 smtp_inend - smtp_inptr > n ? "..." : "");
653 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
654 US"SMTP synchronization error");
655 goto repeat_until_rset;
658 /* If not the last, ack the received chunk. The last response is delayed
659 until after the data ACL decides on it */
661 if (chunking_state == CHUNKING_LAST)
664 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
669 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
670 chunking_state = CHUNKING_OFFERED;
671 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
673 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
674 QUIT, RSET or NOOP but handling them seems obvious */
677 switch(smtp_read_command(TRUE, 1))
680 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
681 US"only BDAT permissible after non-LAST BDAT");
684 switch(smtp_read_command(TRUE, 1))
686 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
687 case EOF_CMD: return EOF;
688 case RSET_CMD: smtp_rset_handler(); return ERR;
689 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
690 US"only RSET accepted now") > 0)
692 goto repeat_until_rset;
696 smtp_quit_handler(&user_msg, &log_msg);
707 smtp_printf("250 OK\r\n", FALSE);
714 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
716 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
717 US"missing size for BDAT command");
720 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
721 ? CHUNKING_LAST : CHUNKING_ACTIVE;
722 chunking_data_left = chunking_datasize;
723 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
724 (int)chunking_state, chunking_data_left);
726 if (chunking_datasize == 0)
727 if (chunking_state == CHUNKING_LAST)
731 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
732 US"zero size for BDAT command");
733 goto repeat_until_rset;
736 bdat_push_receive_functions();
738 dkim_collect_input = dkim_save;
740 break; /* to top of main loop */
747 bdat_getbuf(unsigned * len)
751 if (chunking_data_left <= 0)
752 { *len = 0; return NULL; }
754 if (*len > chunking_data_left) *len = chunking_data_left;
755 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
756 chunking_data_left -= *len;
761 bdat_flush_data(void)
763 while (chunking_data_left)
765 unsigned n = chunking_data_left;
766 if (!bdat_getbuf(&n)) break;
769 bdat_pop_receive_functions();
771 if (chunking_state != CHUNKING_LAST)
773 chunking_state = CHUNKING_OFFERED;
774 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
780 bdat_push_receive_functions(void)
782 /* push the current receive_* function on the "stack", and
783 replace them by bdat_getc(), which in turn will use the lwr_receive_*
784 functions to do the dirty work. */
785 if (lwr_receive_getc == NULL)
787 lwr_receive_getc = receive_getc;
788 lwr_receive_getbuf = receive_getbuf;
789 lwr_receive_ungetc = receive_ungetc;
793 DEBUG(D_receive) debug_printf("chunking double-push receive functions\n");
796 receive_getc = bdat_getc;
797 receive_getbuf = bdat_getbuf;
798 receive_ungetc = bdat_ungetc;
802 bdat_pop_receive_functions(void)
804 if (lwr_receive_getc == NULL)
806 DEBUG(D_receive) debug_printf("chunking double-pop receive functions\n");
809 receive_getc = lwr_receive_getc;
810 receive_getbuf = lwr_receive_getbuf;
811 receive_ungetc = lwr_receive_ungetc;
813 lwr_receive_getc = NULL;
814 lwr_receive_getbuf = NULL;
815 lwr_receive_ungetc = NULL;
818 /*************************************************
819 * SMTP version of ungetc() *
820 *************************************************/
822 /* Puts a character back in the input buffer. Only ever
828 Returns: the character
834 if (smtp_inptr <= smtp_inbuffer)
835 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "buffer underflow in smtp_ungetc");
845 chunking_data_left++;
846 return lwr_receive_ungetc(ch);
851 /*************************************************
852 * SMTP version of feof() *
853 *************************************************/
855 /* Tests for a previous EOF
858 Returns: non-zero if the eof flag is set
870 /*************************************************
871 * SMTP version of ferror() *
872 *************************************************/
874 /* Tests for a previous read error, and returns with errno
875 restored to what it was when the error was detected.
878 Returns: non-zero if the error flag is set
884 errno = smtp_had_error;
885 return smtp_had_error;
890 /*************************************************
891 * Test for characters in the SMTP buffer *
892 *************************************************/
894 /* Used at the end of a message
903 return smtp_inptr < smtp_inend;
908 /*************************************************
909 * Write formatted string to SMTP channel *
910 *************************************************/
912 /* This is a separate function so that we don't have to repeat everything for
913 TLS support or debugging. It is global so that the daemon and the
914 authentication functions can use it. It does not return any error indication,
915 because major problems such as dropped connections won't show up till an output
916 flush for non-TLS connections. The smtp_fflush() function is available for
917 checking that: for convenience, TLS output errors are remembered here so that
918 they are also picked up later by smtp_fflush().
920 This function is exposed to the local_scan API; do not change the signature.
924 more further data expected
925 ... optional arguments
931 smtp_printf(const char *format, BOOL more, ...)
936 smtp_vprintf(format, more, ap);
940 /* This is split off so that verify.c:respond_printf() can, in effect, call
941 smtp_printf(), bearing in mind that in C a vararg function can't directly
942 call another vararg function, only a function which accepts a va_list.
944 This function is exposed to the local_scan API; do not change the signature.
946 /*XXX consider passing caller-info in, for string_vformat-onward */
949 smtp_vprintf(const char *format, BOOL more, va_list ap)
951 gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
954 /* Use taint-unchecked routines for writing into big_buffer, trusting
955 that we'll never expand it. */
957 yield = !! string_vformat(&gs, SVFMT_TAINT_NOCHK, format, ap);
958 string_from_gstring(&gs);
962 uschar *msg_copy, *cr, *end;
963 msg_copy = string_copy(gs.s);
964 end = msg_copy + gs.ptr;
965 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
966 memmove(cr, cr + 1, (end--) - cr);
967 debug_printf("SMTP>> %s", msg_copy);
972 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
973 smtp_closedown(US"Unexpected error");
974 exim_exit(EXIT_FAILURE);
977 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
978 have had the same. Note: this code is also present in smtp_respond(). It would
979 be tidier to have it only in one place, but when it was added, it was easier to
980 do it that way, so as not to have to mess with the code for the RCPT command,
981 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
983 if (fl.rcpt_in_progress)
985 if (rcpt_smtp_response == NULL)
986 rcpt_smtp_response = string_copy(big_buffer);
987 else if (fl.rcpt_smtp_response_same &&
988 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
989 fl.rcpt_smtp_response_same = FALSE;
990 fl.rcpt_in_progress = FALSE;
993 /* Now write the string */
997 tls_in.active.sock >= 0 ? (tls_write(NULL, gs.s, gs.ptr, more) < 0) :
999 (fwrite(gs.s, gs.ptr, 1, smtp_out) == 0)
1001 smtp_write_error = -1;
1006 /*************************************************
1007 * Flush SMTP out and check for error *
1008 *************************************************/
1010 /* This function isn't currently used within Exim (it detects errors when it
1011 tries to read the next SMTP input), but is available for use in local_scan().
1012 It flushes the output and checks for errors.
1015 Returns: 0 for no error; -1 after an error
1021 if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
1025 tls_in.active.sock >= 0 ? (tls_write(NULL, NULL, 0, FALSE) < 0) :
1027 (fflush(smtp_out) != 0)
1029 smtp_write_error = -1;
1031 return smtp_write_error;
1036 /*************************************************
1037 * SMTP command read timeout *
1038 *************************************************/
1040 /* Signal handler for timing out incoming SMTP commands. This attempts to
1043 Argument: signal number (SIGALRM)
1048 command_timeout_handler(int sig)
1050 had_command_timeout = sig;
1055 /*************************************************
1056 * SIGTERM received *
1057 *************************************************/
1059 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
1061 Argument: signal number (SIGTERM)
1066 command_sigterm_handler(int sig)
1068 had_command_sigterm = sig;
1074 #ifdef SUPPORT_PROXY
1075 /*************************************************
1076 * Restore socket timeout to previous value *
1077 *************************************************/
1078 /* If the previous value was successfully retrieved, restore
1079 it before returning control to the non-proxy routines
1081 Arguments: fd - File descriptor for input
1082 get_ok - Successfully retrieved previous values
1083 tvtmp - Time struct with previous values
1084 vslen - Length of time struct
1088 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
1091 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
1094 /*************************************************
1095 * Check if host is required proxy host *
1096 *************************************************/
1097 /* The function determines if inbound host will be a regular smtp host
1098 or if it is configured that it must use Proxy Protocol. A local
1106 check_proxy_protocol_host()
1110 if ( sender_host_address
1111 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
1112 sender_host_address, NULL)) == OK)
1115 debug_printf("Detected proxy protocol configured host\n");
1116 proxy_session = TRUE;
1118 return proxy_session;
1122 /*************************************************
1123 * Read data until newline or end of buffer *
1124 *************************************************/
1125 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1126 read an entire buffer and assume there will be nothing past a proxy protocol
1127 header. Our approach normally is to use stdio, but again that relies upon
1128 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1129 reading _nothing_ before client TLS handshake. So we don't want to use the
1130 usual buffering reads which may read enough to block TLS starting.
1132 So unfortunately we're down to "read one byte at a time, with a syscall each,
1133 and expect a little overhead", for all proxy-opened connections which are v1,
1134 just to handle the TLS-on-connect case. Since SSL functions wrap the
1135 underlying fd, we can't assume that we can feed them any already-read content.
1137 We need to know where to read to, the max capacity, and we'll read until we
1138 get a CR and one more character. Let the caller scream if it's CR+!LF.
1140 Return the amount read.
1144 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1146 uschar *to = base + already;
1152 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1153 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1155 cr = memchr(base, '\r', already);
1158 if ((cr - base) < already - 1)
1160 /* \r and presumed \n already within what we have; probably not
1161 actually proxy protocol, but abort cleanly. */
1164 /* \r is last character read, just need one more. */
1168 while (capacity > 0)
1170 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1182 /* reached end without having room for a final newline, abort */
1187 /*************************************************
1188 * Setup host for proxy protocol *
1189 *************************************************/
1190 /* The function configures the connection based on a header from the
1191 inbound host to use Proxy Protocol. The specification is very exact
1192 so exit with an error if do not find the exact required pieces. This
1193 includes an incorrect number of spaces separating args.
1196 Returns: Boolean success
1200 setup_proxy_protocol_host()
1212 struct { /* TCP/UDP over IPv4, len = 12 */
1218 struct { /* TCP/UDP over IPv6, len = 36 */
1219 uint8_t src_addr[16];
1220 uint8_t dst_addr[16];
1224 struct { /* AF_UNIX sockets, len = 216 */
1225 uschar src_addr[108];
1226 uschar dst_addr[108];
1232 /* Temp variables used in PPv2 address:port parsing */
1234 char tmpip[INET_ADDRSTRLEN];
1235 struct sockaddr_in tmpaddr;
1236 char tmpip6[INET6_ADDRSTRLEN];
1237 struct sockaddr_in6 tmpaddr6;
1239 /* We can't read "all data until end" because while SMTP is
1240 server-speaks-first, the TLS handshake is client-speaks-first, so for
1241 TLS-on-connect ports the proxy protocol header will usually be immediately
1242 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1243 reinject data for reading by those. So instead we first read "enough to be
1244 safely read within the header, and figure out how much more to read".
1245 For v1 we will later read to the end-of-line, for v2 we will read based upon
1248 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1249 data is needed total. For v1, where the line looks like:
1250 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1252 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1253 We seem to support that. So, if we read 14 octets then we can tell if we're
1254 v2 or v1. If we're v1, we can continue reading as normal.
1256 If we're v2, we can't slurp up the entire header. We need the length in the
1257 15th & 16th octets, then to read everything after that.
1259 So to safely handle v1 and v2, with client-sent-first supported correctly,
1260 we have to do a minimum of 3 read calls, not 1. Eww.
1263 #define PROXY_INITIAL_READ 14
1264 #define PROXY_V2_HEADER_SIZE 16
1265 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1266 # error Code bug in sizes of data to read for proxy usage
1271 int fd = fileno(smtp_in);
1272 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1273 uschar * iptype; /* To display debug info */
1275 struct timeval tvtmp;
1276 socklen_t vslen = sizeof(struct timeval);
1279 /* Save current socket timeout values */
1280 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1282 /* Proxy Protocol host must send header within a short time
1283 (default 3 seconds) or it's considered invalid */
1284 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1285 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1286 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1291 /* The inbound host was declared to be a Proxy Protocol host, so
1292 don't do a PEEK into the data, actually slurp up enough to be
1293 "safe". Can't take it all because TLS-on-connect clients follow
1294 immediately with TLS handshake. */
1295 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1297 while (ret == -1 && errno == EINTR);
1302 /* For v2, handle reading the length, and then the rest. */
1303 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1308 /* First get the length fields. */
1311 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1312 } while (retmore == -1 && errno == EINTR);
1317 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1319 /* May 2014: haproxy combined the version and command into one byte to
1320 allow two full bytes for the length field in order to proxy SSL
1321 connections. SSL Proxy is not supported in this version of Exim, but
1322 must still separate values here. */
1326 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1330 /* The v2 header will always be 16 bytes per the spec. */
1331 size = 16 + ntohs(hdr.v2.len);
1332 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1333 size, (int)sizeof(hdr));
1335 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1336 amount that we need. Double-check that the size is not unreasonable, then
1338 if (size > sizeof(hdr))
1340 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1348 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1349 } while (retmore == -1 && errno == EINTR);
1353 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1354 } while (ret < size);
1356 } /* end scope for getting rest of data for v2 */
1358 /* At this point: if PROXYv2, we've read the exact size required for all data;
1359 if PROXYv1 then we've read "less than required for any valid line" and should
1362 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1364 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1368 case 0x01: /* PROXY command */
1371 case 0x11: /* TCPv4 address type */
1373 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1374 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1375 if (!string_is_ip_address(US tmpip, NULL))
1377 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1380 proxy_local_address = sender_host_address;
1381 sender_host_address = string_copy(US tmpip);
1382 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1383 proxy_local_port = sender_host_port;
1384 sender_host_port = tmpport;
1385 /* Save dest ip/port */
1386 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1387 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1388 if (!string_is_ip_address(US tmpip, NULL))
1390 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1393 proxy_external_address = string_copy(US tmpip);
1394 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1395 proxy_external_port = tmpport;
1397 case 0x21: /* TCPv6 address type */
1399 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1400 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1401 if (!string_is_ip_address(US tmpip6, NULL))
1403 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1406 proxy_local_address = sender_host_address;
1407 sender_host_address = string_copy(US tmpip6);
1408 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1409 proxy_local_port = sender_host_port;
1410 sender_host_port = tmpport;
1411 /* Save dest ip/port */
1412 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1413 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1414 if (!string_is_ip_address(US tmpip6, NULL))
1416 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1419 proxy_external_address = string_copy(US tmpip6);
1420 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1421 proxy_external_port = tmpport;
1425 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1429 /* Unsupported protocol, keep local connection address */
1431 case 0x00: /* LOCAL command */
1432 /* Keep local connection address for LOCAL */
1437 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1441 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1445 uschar *sp; /* Utility variables follow */
1450 /* get the rest of the line */
1451 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1456 p = string_copy(hdr.v1.line);
1457 end = memchr(p, '\r', ret - 1);
1459 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1461 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1464 *end = '\0'; /* Terminate the string */
1465 size = end + 2 - p; /* Skip header + CRLF */
1466 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1467 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1468 /* Step through the string looking for the required fields. Ensure
1469 strict adherence to required formatting, exit for any error. */
1471 if (!isspace(*(p++)))
1473 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1476 if (!Ustrncmp(p, CCS"TCP4", 4))
1478 else if (!Ustrncmp(p,CCS"TCP6", 4))
1480 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1482 iptype = US"Unknown";
1487 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1491 p += Ustrlen(iptype);
1492 if (!isspace(*(p++)))
1494 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1497 /* Find the end of the arg */
1498 if ((sp = Ustrchr(p, ' ')) == NULL)
1501 debug_printf("Did not find proxied src %s\n", iptype);
1505 if(!string_is_ip_address(p, NULL))
1508 debug_printf("Proxied src arg is not an %s address\n", iptype);
1511 proxy_local_address = sender_host_address;
1512 sender_host_address = p;
1514 if ((sp = Ustrchr(p, ' ')) == NULL)
1517 debug_printf("Did not find proxy dest %s\n", iptype);
1521 if(!string_is_ip_address(p, NULL))
1524 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1527 proxy_external_address = p;
1529 if ((sp = Ustrchr(p, ' ')) == NULL)
1531 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1535 tmp_port = strtol(CCS p, &endc, 10);
1536 if (*endc || tmp_port == 0)
1539 debug_printf("Proxied src port '%s' not an integer\n", p);
1542 proxy_local_port = sender_host_port;
1543 sender_host_port = tmp_port;
1545 if ((sp = Ustrchr(p, '\0')) == NULL)
1547 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1550 tmp_port = strtol(CCS p, &endc, 10);
1551 if (*endc || tmp_port == 0)
1554 debug_printf("Proxy dest port '%s' not an integer\n", p);
1557 proxy_external_port = tmp_port;
1558 /* Already checked for /r /n above. Good V1 header received. */
1562 /* Wrong protocol */
1563 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1564 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1570 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1571 yield = proxy_session;
1573 /* Don't flush any potential buffer contents. Any input on proxyfail
1574 should cause a synchronization failure */
1577 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1582 sender_host_name = NULL;
1583 (void) host_name_lookup();
1584 host_build_sender_fullhost();
1588 f.proxy_session_failed = TRUE;
1590 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1597 /*************************************************
1598 * Read one command line *
1599 *************************************************/
1601 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1602 There are sites that don't do this, and in any case internal SMTP probably
1603 should check only for LF. Consequently, we check here for LF only. The line
1604 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1605 an unknown command. The command is read into the global smtp_cmd_buffer so that
1606 it is available via $smtp_command.
1608 The character reading routine sets up a timeout for each block actually read
1609 from the input (which may contain more than one command). We set up a special
1610 signal handler that closes down the session on a timeout. Control does not
1611 return when it runs.
1614 check_sync if TRUE, check synchronization rules if global option is TRUE
1615 buffer_lim maximum to buffer in lower layer
1617 Returns: a code identifying the command (enumerated above)
1621 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1625 BOOL hadnull = FALSE;
1627 had_command_timeout = 0;
1628 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1630 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1632 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1634 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1642 smtp_cmd_buffer[ptr++] = c;
1645 receive_linecount++; /* For BSMTP errors */
1646 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1648 /* If hit end of file, return pseudo EOF command. Whether we have a
1649 part-line already read doesn't matter, since this is an error state. */
1651 if (c == EOF) return EOF_CMD;
1653 /* Remove any CR and white space at the end of the line, and terminate the
1656 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1657 smtp_cmd_buffer[ptr] = 0;
1659 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1661 /* NULLs are not allowed in SMTP commands */
1663 if (hadnull) return BADCHAR_CMD;
1665 /* Scan command list and return identity, having set the data pointer
1666 to the start of the actual data characters. Check for SMTP synchronization
1669 for (smtp_cmd_list * p = cmd_list; p < cmd_list_end; p++)
1671 #ifdef SUPPORT_PROXY
1672 /* Only allow QUIT command if Proxy Protocol parsing failed */
1673 if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD)
1677 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1678 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1679 || smtp_cmd_buffer[p->len] == 0
1680 || smtp_cmd_buffer[p->len] == ' '
1683 if (smtp_inptr < smtp_inend && /* Outstanding input */
1684 p->cmd < sync_cmd_limit && /* Command should sync */
1685 check_sync && /* Local flag set */
1686 smtp_enforce_sync && /* Global flag set */
1687 sender_host_address != NULL && /* Not local input */
1688 !f.sender_host_notsocket) /* Really is a socket */
1691 /* The variables $smtp_command and $smtp_command_argument point into the
1692 unmodified input buffer. A copy of the latter is taken for actual
1693 processing, so that it can be chopped up into separate parts if necessary,
1694 for example, when processing a MAIL command options such as SIZE that can
1695 follow the sender address. */
1697 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1698 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1699 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1700 smtp_cmd_data = smtp_data_buffer;
1702 /* Count non-mail commands from those hosts that are controlled in this
1703 way. The default is all hosts. We don't waste effort checking the list
1704 until we get a non-mail command, but then cache the result to save checking
1705 again. If there's a DEFER while checking the host, assume it's in the list.
1707 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1708 start of each incoming message by fiddling with the value in the table. */
1710 if (!p->is_mail_cmd)
1712 if (count_nonmail == TRUE_UNSET) count_nonmail =
1713 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1714 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1715 return TOO_MANY_NONMAIL_CMD;
1718 /* If there is data for a command that does not expect it, generate the
1721 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1725 #ifdef SUPPORT_PROXY
1726 /* Only allow QUIT command if Proxy Protocol parsing failed */
1727 if (proxy_session && f.proxy_session_failed)
1728 return PROXY_FAIL_IGNORE_CMD;
1731 /* Enforce synchronization for unknown commands */
1733 if ( smtp_inptr < smtp_inend /* Outstanding input */
1734 && check_sync /* Local flag set */
1735 && smtp_enforce_sync /* Global flag set */
1736 && sender_host_address /* Not local input */
1737 && !f.sender_host_notsocket) /* Really is a socket */
1745 /*************************************************
1746 * Forced closedown of call *
1747 *************************************************/
1749 /* This function is called from log.c when Exim is dying because of a serious
1750 disaster, and also from some other places. If an incoming non-batched SMTP
1751 channel is open, it swallows the rest of the incoming message if in the DATA
1752 phase, sends the reply string, and gives an error to all subsequent commands
1753 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1757 message SMTP reply string to send, excluding the code
1763 smtp_closedown(uschar *message)
1765 if (!smtp_in || smtp_batched_input) return;
1766 receive_swallow_smtp();
1767 smtp_printf("421 %s\r\n", FALSE, message);
1769 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1775 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1780 smtp_printf("250 Reset OK\r\n", FALSE);
1784 smtp_printf("421 %s\r\n", FALSE, message);
1792 /*************************************************
1793 * Set up connection info for logging *
1794 *************************************************/
1796 /* This function is called when logging information about an SMTP connection.
1797 It sets up appropriate source information, depending on the type of connection.
1798 If sender_fullhost is NULL, we are at a very early stage of the connection;
1799 just use the IP address.
1802 Returns: a string describing the connection
1806 smtp_get_connection_info(void)
1808 const uschar * hostname = sender_fullhost
1809 ? sender_fullhost : sender_host_address;
1812 return string_sprintf("SMTP connection from %s", hostname);
1814 if (f.sender_host_unknown || f.sender_host_notsocket)
1815 return string_sprintf("SMTP connection from %s", sender_ident);
1818 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1820 if (LOGGING(incoming_interface) && interface_address)
1821 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1822 interface_address, interface_port);
1824 return string_sprintf("SMTP connection from %s", hostname);
1830 /* Append TLS-related information to a log line
1833 g String under construction: allocated string to extend, or NULL
1835 Returns: Allocated string or NULL
1838 s_tlslog(gstring * g)
1840 if (LOGGING(tls_cipher) && tls_in.cipher)
1842 g = string_append(g, 2, US" X=", tls_in.cipher);
1843 #ifdef EXPERIMENTAL_TLS_RESUME
1844 if (LOGGING(tls_resumption) && tls_in.resumption & RESUME_USED)
1845 g = string_catn(g, US"*", 1);
1848 if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1849 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1850 if (LOGGING(tls_peerdn) && tls_in.peerdn)
1851 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1852 if (LOGGING(tls_sni) && tls_in.sni)
1853 g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
1861 s_connhad_log(gstring * g)
1863 uschar * sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE
1864 ? US" C=..." : US" C=";
1866 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1867 if (smtp_connection_had[i] != SCH_NONE)
1869 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1872 for (int i = 0; i < smtp_ch_index; i++)
1874 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
1881 /*************************************************
1882 * Log lack of MAIL if so configured *
1883 *************************************************/
1885 /* This function is called when an SMTP session ends. If the log selector
1886 smtp_no_mail is set, write a log line giving some details of what has happened
1887 in the SMTP session.
1894 smtp_log_no_mail(void)
1899 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1902 if (sender_host_authenticated)
1904 g = string_append(g, 2, US" A=", sender_host_authenticated);
1905 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
1912 g = s_connhad_log(g);
1914 if (!(s = string_from_gstring(g))) s = US"";
1916 log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1917 f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"",
1918 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
1922 /* Return list of recent smtp commands */
1927 gstring * list = NULL;
1930 for (int i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1931 if (smtp_connection_had[i] != SCH_NONE)
1932 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1934 for (int i = 0; i < smtp_ch_index; i++)
1935 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1937 s = string_from_gstring(list);
1938 return s ? s : US"";
1944 /*************************************************
1945 * Check HELO line and set sender_helo_name *
1946 *************************************************/
1948 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1949 the domain name of the sending host, or an ip literal in square brackets. The
1950 argument is placed in sender_helo_name, which is in malloc store, because it
1951 must persist over multiple incoming messages. If helo_accept_junk is set, this
1952 host is permitted to send any old junk (needed for some broken hosts).
1953 Otherwise, helo_allow_chars can be used for rogue characters in general
1954 (typically people want to let in underscores).
1957 s the data portion of the line (already past any white space)
1959 Returns: TRUE or FALSE
1963 check_helo(uschar *s)
1966 uschar *end = s + Ustrlen(s);
1967 BOOL yield = fl.helo_accept_junk;
1969 /* Discard any previous helo name */
1971 sender_helo_name = NULL;
1973 /* Skip tests if junk is permitted. */
1977 /* Allow the new standard form for IPv6 address literals, namely,
1978 [IPv6:....], and because someone is bound to use it, allow an equivalent
1979 IPv4 form. Allow plain addresses as well. */
1986 if (strncmpic(s, US"[IPv6:", 6) == 0)
1987 yield = (string_is_ip_address(s+6, NULL) == 6);
1988 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1989 yield = (string_is_ip_address(s+6, NULL) == 4);
1991 yield = (string_is_ip_address(s+1, NULL) != 0);
1996 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1997 that have been configured (usually underscore - sigh). */
2000 for (yield = TRUE; *s; s++)
2001 if (!isalnum(*s) && *s != '.' && *s != '-' &&
2002 Ustrchr(helo_allow_chars, *s) == NULL)
2008 /* Save argument if OK */
2010 if (yield) sender_helo_name = string_copy_perm(start, TRUE);
2018 /*************************************************
2019 * Extract SMTP command option *
2020 *************************************************/
2022 /* This function picks the next option setting off the end of smtp_cmd_data. It
2023 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
2024 things that can appear there.
2027 name point this at the name
2028 value point this at the data string
2030 Returns: TRUE if found an option
2034 extract_option(uschar **name, uschar **value)
2038 if (Ustrlen(smtp_cmd_data) <= 0) return FALSE;
2039 v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
2040 while (v > smtp_cmd_data && isspace(*v)) v--;
2043 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
2045 /* Take care to not stop at a space embedded in a quoted local-part */
2048 do v--; while (v > smtp_cmd_data && *v != '"');
2049 if (v <= smtp_cmd_data) return FALSE;
2053 if (v <= smtp_cmd_data) return FALSE;
2058 while (n > smtp_cmd_data && isalpha(n[-1])) n--;
2059 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
2060 if (n <= smtp_cmd_data || !isspace(n[-1])) return FALSE;
2077 /*************************************************
2078 * Reset for new message *
2079 *************************************************/
2081 /* This function is called whenever the SMTP session is reset from
2082 within either of the setup functions; also from the daemon loop.
2084 Argument: the stacking pool storage reset point
2089 smtp_reset(void *reset_point)
2091 recipients_list = NULL;
2092 rcpt_count = rcpt_defer_count = rcpt_fail_count =
2093 raw_recipients_count = recipients_count = recipients_list_max = 0;
2094 message_linecount = 0;
2096 acl_added_headers = NULL;
2097 acl_removed_headers = NULL;
2098 f.queue_only_policy = FALSE;
2099 rcpt_smtp_response = NULL;
2100 fl.rcpt_smtp_response_same = TRUE;
2101 fl.rcpt_in_progress = FALSE;
2102 f.deliver_freeze = FALSE; /* Can be set by ACL */
2103 freeze_tell = freeze_tell_config; /* Can be set by ACL */
2104 fake_response = OK; /* Can be set by ACL */
2105 #ifdef WITH_CONTENT_SCAN
2106 f.no_mbox_unspool = FALSE; /* Can be set by ACL */
2108 f.submission_mode = FALSE; /* Can be set by ACL */
2109 f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */
2110 f.active_local_from_check = local_from_check; /* Can be set by ACL */
2111 f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
2112 sending_ip_address = NULL;
2113 return_path = sender_address = NULL;
2114 deliver_localpart_data = deliver_domain_data =
2115 recipient_data = sender_data = NULL; /* Can be set by ACL */
2116 deliver_localpart_parent = deliver_localpart_orig = NULL;
2117 deliver_domain_parent = deliver_domain_orig = NULL;
2118 callout_address = NULL;
2119 submission_name = NULL; /* Can be set by ACL */
2120 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
2121 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
2122 sender_verified_list = NULL; /* No senders verified */
2123 memset(sender_address_cache, 0, sizeof(sender_address_cache));
2124 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
2126 authenticated_sender = NULL;
2127 #ifdef EXPERIMENTAL_BRIGHTMAIL
2129 bmi_verdicts = NULL;
2131 dnslist_domain = dnslist_matched = NULL;
2133 spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL;
2134 spf_result_guessed = FALSE;
2136 #ifndef DISABLE_DKIM
2137 dkim_cur_signer = dkim_signers =
2138 dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL;
2139 dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL;
2140 f.dkim_disable_verify = FALSE;
2141 dkim_collect_input = 0;
2142 dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL;
2143 dkim_key_length = 0;
2145 #ifdef SUPPORT_DMARC
2146 f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE;
2147 dmarc_domain_policy = dmarc_status = dmarc_status_text =
2148 dmarc_used_domain = NULL;
2150 #ifdef EXPERIMENTAL_ARC
2151 arc_state = arc_state_reason = NULL;
2152 arc_received_instance = 0;
2156 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2157 #ifndef DISABLE_PRDR
2158 prdr_requested = FALSE;
2161 message_smtputf8 = FALSE;
2163 body_linecount = body_zerocount = 0;
2165 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2166 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2167 /* Note that ratelimiters_conn persists across resets. */
2169 /* Reset message ACL variables */
2173 /* The message body variables use malloc store. They may be set if this is
2174 not the first message in an SMTP session and the previous message caused them
2175 to be referenced in an ACL. */
2179 store_free(message_body);
2180 message_body = NULL;
2183 if (message_body_end)
2185 store_free(message_body_end);
2186 message_body_end = NULL;
2189 /* Warning log messages are also saved in malloc store. They are saved to avoid
2190 repetition in the same message, but it seems right to repeat them for different
2193 while (acl_warn_logged)
2195 string_item *this = acl_warn_logged;
2196 acl_warn_logged = acl_warn_logged->next;
2199 store_reset(reset_point);
2200 return store_mark();
2207 /*************************************************
2208 * Initialize for incoming batched SMTP message *
2209 *************************************************/
2211 /* This function is called from smtp_setup_msg() in the case when
2212 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2213 of messages in one file with SMTP commands between them. All errors must be
2214 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2215 relevant. After an error on a sender, or an invalid recipient, the remainder
2216 of the message is skipped. The value of received_protocol is already set.
2219 Returns: > 0 message successfully started (reached DATA)
2220 = 0 QUIT read or end of file reached
2221 < 0 should not occur
2225 smtp_setup_batch_msg(void)
2228 rmark reset_point = store_mark();
2230 /* Save the line count at the start of each transaction - single commands
2231 like HELO and RSET count as whole transactions. */
2233 bsmtp_transaction_linecount = receive_linecount;
2235 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2237 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2238 reset_point = smtp_reset(reset_point); /* Reset for start of message */
2240 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2241 value. The values are 2 larger than the required yield of the function. */
2246 uschar *recipient = NULL;
2247 int start, end, sender_domain, recipient_domain;
2249 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2251 /* The HELO/EHLO commands set sender_address_helo if they have
2252 valid data; otherwise they are ignored, except that they do
2253 a reset of the state. */
2258 check_helo(smtp_cmd_data);
2262 cancel_cutthrough_connection(TRUE, US"RSET received");
2263 reset_point = smtp_reset(reset_point);
2264 bsmtp_transaction_linecount = receive_linecount;
2268 /* The MAIL FROM command requires an address as an operand. All we
2269 do here is to parse it for syntactic correctness. The form "<>" is
2270 a special case which converts into an empty string. The start/end
2271 pointers in the original are not used further for this address, as
2272 it is the canonical extracted address which is all that is kept. */
2275 smtp_mailcmd_count++; /* Count for no-mail log */
2276 if (sender_address != NULL)
2277 /* The function moan_smtp_batch() does not return. */
2278 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2280 if (smtp_cmd_data[0] == 0)
2281 /* The function moan_smtp_batch() does not return. */
2282 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2284 /* Reset to start of message */
2286 cancel_cutthrough_connection(TRUE, US"MAIL received");
2287 reset_point = smtp_reset(reset_point);
2289 /* Apply SMTP rewrite */
2291 raw_sender = rewrite_existflags & rewrite_smtp
2292 /* deconst ok as smtp_cmd_data was not const */
2293 ? US rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL,
2294 FALSE, US"", global_rewrite_rules)
2297 /* Extract the address; the TRUE flag allows <> as valid */
2300 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2304 /* The function moan_smtp_batch() does not return. */
2305 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2307 sender_address = string_copy(raw_sender);
2309 /* Qualify unqualified sender addresses if permitted to do so. */
2312 && sender_address[0] != 0 && sender_address[0] != '@')
2313 if (f.allow_unqualified_sender)
2315 /* deconst ok as sender_address was not const */
2316 sender_address = US rewrite_address_qualify(sender_address, FALSE);
2317 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2318 "and rewritten\n", raw_sender);
2320 /* The function moan_smtp_batch() does not return. */
2322 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2327 /* The RCPT TO command requires an address as an operand. All we do
2328 here is to parse it for syntactic correctness. There may be any number
2329 of RCPT TO commands, specifying multiple senders. We build them all into
2330 a data structure that is in argc/argv format. The start/end values
2331 given by parse_extract_address are not used, as we keep only the
2332 extracted address. */
2335 if (!sender_address)
2336 /* The function moan_smtp_batch() does not return. */
2337 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2339 if (smtp_cmd_data[0] == 0)
2340 /* The function moan_smtp_batch() does not return. */
2341 moan_smtp_batch(smtp_cmd_buffer,
2342 "501 RCPT TO must have an address operand");
2344 /* Check maximum number allowed */
2346 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2347 /* The function moan_smtp_batch() does not return. */
2348 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2349 recipients_max_reject? "552": "452");
2351 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2352 recipient address */
2354 recipient = rewrite_existflags & rewrite_smtp
2355 /* deconst ok as smtp_cmd_data was not const */
2356 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2357 global_rewrite_rules)
2360 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2361 &recipient_domain, FALSE);
2364 /* The function moan_smtp_batch() does not return. */
2365 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2367 /* If the recipient address is unqualified, qualify it if permitted. Then
2368 add it to the list of recipients. */
2370 if (!recipient_domain)
2371 if (f.allow_unqualified_recipient)
2373 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2375 /* deconst ok as recipient was not const */
2376 recipient = US rewrite_address_qualify(recipient, TRUE);
2378 /* The function moan_smtp_batch() does not return. */
2380 moan_smtp_batch(smtp_cmd_buffer,
2381 "501 recipient address must contain a domain");
2383 receive_add_recipient(recipient, -1);
2387 /* The DATA command is legal only if it follows successful MAIL FROM
2388 and RCPT TO commands. This function is complete when a valid DATA
2389 command is encountered. */
2392 if (!sender_address || recipients_count <= 0)
2393 /* The function moan_smtp_batch() does not return. */
2394 if (!sender_address)
2395 moan_smtp_batch(smtp_cmd_buffer,
2396 "503 MAIL FROM:<sender> command must precede DATA");
2398 moan_smtp_batch(smtp_cmd_buffer,
2399 "503 RCPT TO:<recipient> must precede DATA");
2402 done = 3; /* DATA successfully achieved */
2403 message_ended = END_NOTENDED; /* Indicate in middle of message */
2408 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2415 bsmtp_transaction_linecount = receive_linecount;
2426 /* The function moan_smtp_batch() does not return. */
2427 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2432 /* The function moan_smtp_batch() does not return. */
2433 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2438 /* The function moan_smtp_batch() does not return. */
2439 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2444 return done - 2; /* Convert yield values */
2452 smtp_log_tls_fail(uschar * errstr)
2454 uschar * conn_info = smtp_get_connection_info();
2456 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2457 /* I'd like to get separated H= here, but too hard for now */
2459 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2473 socklen_t len = sizeof(is_fastopen);
2475 /* The tinfo TCPOPT_FAST_OPEN bit seems unreliable, and we don't see state
2476 TCP_SYN_RCV (as of 12.1) so no idea about data-use. */
2478 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
2483 debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
2484 f.tcp_in_fastopen = TRUE;
2487 else DEBUG(D_receive)
2488 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2490 # elif defined(TCP_INFO)
2491 struct tcp_info tinfo;
2492 socklen_t len = sizeof(tinfo);
2494 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
2495 # ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11,12 do not seem to have this yet */
2496 if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
2499 debug_printf("TFO mode connection (ACKd data-on-SYN)\n");
2500 f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
2504 if (tinfo.tcpi_state == TCP_SYN_RECV) /* Not seen on FreeBSD 12.1 */
2507 debug_printf("TFO mode connection (state TCP_SYN_RECV)\n");
2508 f.tcp_in_fastopen = TRUE;
2510 else DEBUG(D_receive)
2511 debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
2517 /*************************************************
2518 * Start an SMTP session *
2519 *************************************************/
2521 /* This function is called at the start of an SMTP session. Thereafter,
2522 smtp_setup_msg() is called to initiate each separate message. This
2523 function does host-specific testing, and outputs the banner line.
2526 Returns: FALSE if the session can not continue; something has
2527 gone wrong, or the connection to the host is blocked
2531 smtp_start_session(void)
2534 uschar *user_msg, *log_msg;
2539 gettimeofday(&smtp_connection_start, NULL);
2540 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2541 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2544 /* Default values for certain variables */
2546 fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE;
2547 smtp_mailcmd_count = 0;
2548 count_nonmail = TRUE_UNSET;
2549 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2550 smtp_delay_mail = smtp_rlm_base;
2551 fl.auth_advertised = FALSE;
2552 f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE;
2553 f.pipelining_enable = TRUE;
2554 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2555 fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2557 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2558 authentication settings from -oMaa to remain in force. */
2560 if (!host_checking && !f.sender_host_notsocket)
2561 sender_host_auth_pubname = sender_host_authenticated = NULL;
2562 authenticated_by = NULL;
2565 tls_in.ver = tls_in.cipher = tls_in.peerdn = NULL;
2566 tls_in.ourcert = tls_in.peercert = NULL;
2568 tls_in.ocsp = OCSP_NOT_REQ;
2569 fl.tls_advertised = FALSE;
2571 fl.dsn_advertised = FALSE;
2573 fl.smtputf8_advertised = FALSE;
2576 /* Reset ACL connection variables */
2580 /* Allow for trailing 0 in the command and data buffers. Tainted. */
2582 smtp_cmd_buffer = store_get_perm(2*SMTP_CMD_BUFFER_SIZE + 2, TRUE);
2584 smtp_cmd_buffer[0] = 0;
2585 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2587 /* For batched input, the protocol setting can be overridden from the
2588 command line by a trusted caller. */
2590 if (smtp_batched_input)
2592 if (!received_protocol) received_protocol = US"local-bsmtp";
2595 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2596 reset later if any of EHLO/AUTH/STARTTLS are received. */
2600 (sender_host_address ? protocols : protocols_local) [pnormal];
2602 /* Set up the buffer for inputting using direct read() calls, and arrange to
2603 call the local functions instead of the standard C ones. Place a NUL at the
2604 end of the buffer to safety-stop C-string reads from it. */
2606 if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
2607 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2608 smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0';
2610 receive_getc = smtp_getc;
2611 receive_getbuf = smtp_getbuf;
2612 receive_get_cache = smtp_get_cache;
2613 receive_ungetc = smtp_ungetc;
2614 receive_feof = smtp_feof;
2615 receive_ferror = smtp_ferror;
2616 receive_smtp_buffered = smtp_buffered;
2617 lwr_receive_getc = NULL;
2618 lwr_receive_getbuf = NULL;
2619 lwr_receive_ungetc = NULL;
2620 smtp_inptr = smtp_inend = smtp_inbuffer;
2621 smtp_had_eof = smtp_had_error = 0;
2623 /* Set up the message size limit; this may be host-specific */
2625 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2626 if (expand_string_message)
2628 if (thismessage_size_limit == -1)
2629 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2630 "%s", expand_string_message);
2632 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2633 "%s", expand_string_message);
2634 smtp_closedown(US"Temporary local problem - please try later");
2638 /* When a message is input locally via the -bs or -bS options, sender_host_
2639 unknown is set unless -oMa was used to force an IP address, in which case it
2640 is checked like a real remote connection. When -bs is used from inetd, this
2641 flag is not set, causing the sending host to be checked. The code that deals
2642 with IP source routing (if configured) is never required for -bs or -bS and
2643 the flag sender_host_notsocket is used to suppress it.
2645 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2646 reserve for certain hosts and/or networks. */
2648 if (!f.sender_host_unknown)
2651 BOOL reserved_host = FALSE;
2653 /* Look up IP options (source routing info) on the socket if this is not an
2654 -oMa "host", and if any are found, log them and drop the connection.
2656 Linux (and others now, see below) is different to everyone else, so there
2657 has to be some conditional compilation here. Versions of Linux before 2.1.15
2658 used a structure whose name was "options". Somebody finally realized that
2659 this name was silly, and it got changed to "ip_options". I use the
2660 newer name here, but there is a fudge in the script that sets up os.h
2661 to define a macro in older Linux systems.
2663 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2664 glibc 2, which has chosen ip_opts for the structure name. This is now
2665 really a glibc thing rather than a Linux thing, so the condition name
2666 has been changed to reflect this. It is relevant also to GNU/Hurd.
2668 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2669 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2670 a special macro defined in the os.h file.
2672 Some DGUX versions on older hardware appear not to support IP options at
2673 all, so there is now a general macro which can be set to cut out this
2676 How to do this properly in IPv6 is not yet known. */
2678 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2680 #ifdef GLIBC_IP_OPTIONS
2681 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2686 #elif defined DARWIN_IP_OPTIONS
2692 if (!host_checking && !f.sender_host_notsocket)
2695 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2696 struct ip_options *ipopt = store_get(optlen, FALSE);
2698 struct ip_opts ipoptblock;
2699 struct ip_opts *ipopt = &ipoptblock;
2700 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2702 struct ipoption ipoptblock;
2703 struct ipoption *ipopt = &ipoptblock;
2704 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2707 /* Occasional genuine failures of getsockopt() have been seen - for
2708 example, "reset by peer". Therefore, just log and give up on this
2709 call, unless the error is ENOPROTOOPT. This error is given by systems
2710 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2711 of writing. So for that error, carry on - we just can't do an IP options
2714 DEBUG(D_receive) debug_printf("checking for IP options\n");
2716 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
2719 if (errno != ENOPROTOOPT)
2721 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2722 host_and_ident(FALSE), strerror(errno));
2723 smtp_printf("451 SMTP service not available\r\n", FALSE);
2728 /* Deal with any IP options that are set. On the systems I have looked at,
2729 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2730 more logging data than will fit in big_buffer. Nevertheless, after somebody
2731 questioned this code, I've added in some paranoid checking. */
2733 else if (optlen > 0)
2735 uschar *p = big_buffer;
2736 uschar *pend = big_buffer + big_buffer_size;
2739 struct in_addr addr;
2742 uschar *optstart = US (ipopt->__data);
2744 uschar *optstart = US (ipopt->ip_opts);
2746 uschar *optstart = US (ipopt->ipopt_list);
2749 DEBUG(D_receive) debug_printf("IP options exist\n");
2751 Ustrcpy(p, "IP options on incoming call:");
2754 for (uschar * opt = optstart; opt && opt < US (ipopt) + optlen; )
2767 if (!string_format(p, pend-p, " %s [@%s",
2768 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2770 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2772 inet_ntoa(ipopt->ip_dst)))
2774 inet_ntoa(ipopt->ipopt_dst)))
2782 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2784 while (optcount-- > 0)
2786 memcpy(&addr, adptr, sizeof(addr));
2787 if (!string_format(p, pend - p - 1, "%s%s",
2788 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2794 adptr += sizeof(struct in_addr);
2802 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2805 for (int i = 0; i < opt[1]; i++)
2806 p += sprintf(CS p, "%2.2x ", opt[i]);
2814 log_write(0, LOG_MAIN, "%s", big_buffer);
2816 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2818 log_write(0, LOG_MAIN|LOG_REJECT,
2819 "connection from %s refused (IP options)", host_and_ident(FALSE));
2821 smtp_printf("554 SMTP service not available\r\n", FALSE);
2825 /* Length of options = 0 => there are no options */
2827 else DEBUG(D_receive) debug_printf("no IP options found\n");
2829 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2831 /* Set keep-alive in socket options. The option is on by default. This
2832 setting is an attempt to get rid of some hanging connections that stick in
2833 read() when the remote end (usually a dialup) goes away. */
2835 if (smtp_accept_keepalive && !f.sender_host_notsocket)
2836 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2838 /* If the current host matches host_lookup, set the name by doing a
2839 reverse lookup. On failure, sender_host_name will be NULL and
2840 host_lookup_failed will be TRUE. This may or may not be serious - optional
2843 if (verify_check_host(&host_lookup) == OK)
2845 (void)host_name_lookup();
2846 host_build_sender_fullhost();
2849 /* Delay this until we have the full name, if it is looked up. */
2851 set_process_info("handling incoming connection from %s",
2852 host_and_ident(FALSE));
2854 /* Expand smtp_receive_timeout, if needed */
2856 if (smtp_receive_timeout_s)
2859 if ( !(exp = expand_string(smtp_receive_timeout_s))
2861 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2863 log_write(0, LOG_MAIN|LOG_PANIC,
2864 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2867 /* Test for explicit connection rejection */
2869 if (verify_check_host(&host_reject_connection) == OK)
2871 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2872 "from %s (host_reject_connection)", host_and_ident(FALSE));
2873 smtp_printf("554 SMTP service not available\r\n", FALSE);
2877 /* Test with TCP Wrappers if so configured. There is a problem in that
2878 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2879 such as disks dying. In these cases, it is desirable to reject with a 4xx
2880 error instead of a 5xx error. There isn't a "right" way to detect such
2881 problems. The following kludge is used: errno is zeroed before calling
2882 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2883 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2886 #ifdef USE_TCP_WRAPPERS
2888 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2889 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2890 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2891 expand_string_message);
2893 if (!hosts_ctl(tcp_wrappers_name,
2894 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2895 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2896 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2898 if (errno == 0 || errno == ENOENT)
2900 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2901 log_write(L_connection_reject,
2902 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2903 "(tcp wrappers)", host_and_ident(FALSE));
2904 smtp_printf("554 SMTP service not available\r\n", FALSE);
2908 int save_errno = errno;
2909 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2910 "errno value %d\n", save_errno);
2911 log_write(L_connection_reject,
2912 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2913 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2914 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2920 /* Check for reserved slots. The value of smtp_accept_count has already been
2921 incremented to include this process. */
2923 if (smtp_accept_max > 0 &&
2924 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2926 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2928 log_write(L_connection_reject,
2929 LOG_MAIN, "temporarily refused connection from %s: not in "
2930 "reserve list: connected=%d max=%d reserve=%d%s",
2931 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2932 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2933 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2934 "please try again later\r\n", FALSE, smtp_active_hostname);
2937 reserved_host = TRUE;
2940 /* If a load level above which only messages from reserved hosts are
2941 accepted is set, check the load. For incoming calls via the daemon, the
2942 check is done in the superior process if there are no reserved hosts, to
2943 save a fork. In all cases, the load average will already be available
2944 in a global variable at this point. */
2946 if (smtp_load_reserve >= 0 &&
2947 load_average > smtp_load_reserve &&
2949 verify_check_host(&smtp_reserve_hosts) != OK)
2951 log_write(L_connection_reject,
2952 LOG_MAIN, "temporarily refused connection from %s: not in "
2953 "reserve list and load average = %.2f", host_and_ident(FALSE),
2954 (double)load_average/1000.0);
2955 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2956 smtp_active_hostname);
2960 /* Determine whether unqualified senders or recipients are permitted
2961 for this host. Unfortunately, we have to do this every time, in order to
2962 set the flags so that they can be inspected when considering qualifying
2963 addresses in the headers. For a site that permits no qualification, this
2964 won't take long, however. */
2966 f.allow_unqualified_sender =
2967 verify_check_host(&sender_unqualified_hosts) == OK;
2969 f.allow_unqualified_recipient =
2970 verify_check_host(&recipient_unqualified_hosts) == OK;
2972 /* Determine whether HELO/EHLO is required for this host. The requirement
2973 can be hard or soft. */
2975 fl.helo_required = verify_check_host(&helo_verify_hosts) == OK;
2976 if (!fl.helo_required)
2977 fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2979 /* Determine whether this hosts is permitted to send syntactic junk
2980 after a HELO or EHLO command. */
2982 fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2985 /* For batch SMTP input we are now done. */
2987 if (smtp_batched_input) return TRUE;
2989 /* If valid Proxy Protocol source is connecting, set up session.
2990 * Failure will not allow any SMTP function other than QUIT. */
2992 #ifdef SUPPORT_PROXY
2993 proxy_session = FALSE;
2994 f.proxy_session_failed = FALSE;
2995 if (check_proxy_protocol_host())
2996 setup_proxy_protocol_host();
2999 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
3000 smtps port for use with older style SSL MTAs. */
3003 if (tls_in.on_connect)
3005 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
3006 return smtp_log_tls_fail(user_msg);
3007 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3011 /* Run the connect ACL if it exists */
3014 if (acl_smtp_connect)
3017 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
3020 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
3025 /* Output the initial message for a two-way SMTP connection. It may contain
3026 newlines, which then cause a multi-line response to be given. */
3028 code = US"220"; /* Default status code */
3029 esc = US""; /* Default extended status code */
3030 esclen = 0; /* Length of esc */
3034 if (!(s = expand_string(smtp_banner)))
3035 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
3036 "failed: %s", smtp_banner, expand_string_message);
3042 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
3046 esclen = codelen - 4;
3050 /* Remove any terminating newlines; might as well remove trailing space too */
3053 while (p > s && isspace(p[-1])) p--;
3056 /* It seems that CC:Mail is braindead, and assumes that the greeting message
3057 is all contained in a single IP packet. The original code wrote out the
3058 greeting using several calls to fprint/fputc, and on busy servers this could
3059 cause it to be split over more than one packet - which caused CC:Mail to fall
3060 over when it got the second part of the greeting after sending its first
3061 command. Sigh. To try to avoid this, build the complete greeting message
3062 first, and output it in one fell swoop. This gives a better chance of it
3063 ending up as a single packet. */
3065 ss = string_get(256);
3068 do /* At least once, in case we have an empty string */
3071 uschar *linebreak = Ustrchr(p, '\n');
3072 ss = string_catn(ss, code, 3);
3076 ss = string_catn(ss, US" ", 1);
3080 len = linebreak - p;
3081 ss = string_catn(ss, US"-", 1);
3083 ss = string_catn(ss, esc, esclen);
3084 ss = string_catn(ss, p, len);
3085 ss = string_catn(ss, US"\r\n", 2);
3091 /* Before we write the banner, check that there is no input pending, unless
3092 this synchronisation check is disabled. */
3094 #ifndef DISABLE_PIPE_CONNECT
3095 fl.pipe_connect_acceptable =
3096 sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
3099 if (fl.pipe_connect_acceptable)
3100 f.smtp_in_early_pipe_used = TRUE;
3106 unsigned n = smtp_inend - smtp_inptr;
3107 if (n > 128) n = 128;
3109 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
3110 "synchronization error (input sent without waiting for greeting): "
3111 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
3112 string_printing(string_copyn(smtp_inptr, n)));
3113 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
3117 /* Now output the banner */
3118 /*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */
3121 #ifndef DISABLE_PIPE_CONNECT
3122 fl.pipe_connect_acceptable && pipeline_connect_sends(),
3126 string_from_gstring(ss));
3128 /* Attempt to see if we sent the banner before the last ACK of the 3-way
3129 handshake arrived. If so we must have managed a TFO. */
3132 if (sender_host_address && !f.sender_host_notsocket) tfo_in_check();
3142 /*************************************************
3143 * Handle SMTP syntax and protocol errors *
3144 *************************************************/
3146 /* Write to the log for SMTP syntax errors in incoming commands, if configured
3147 to do so. Then transmit the error response. The return value depends on the
3148 number of syntax and protocol errors in this SMTP session.
3151 type error type, given as a log flag bit
3152 code response code; <= 0 means don't send a response
3153 data data to reflect in the response (can be NULL)
3154 errmess the error message
3156 Returns: -1 limit of syntax/protocol errors NOT exceeded
3157 +1 limit of syntax/protocol errors IS exceeded
3159 These values fit in with the values of the "done" variable in the main
3160 processing loop in smtp_setup_msg(). */
3163 synprot_error(int type, int code, uschar *data, uschar *errmess)
3167 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
3168 type == L_smtp_syntax_error ? "syntax" : "protocol",
3169 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
3171 if (++synprot_error_count > smtp_max_synprot_errors)
3174 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3175 "syntax or protocol errors (last command was \"%s\", %s)",
3176 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
3177 string_from_gstring(s_connhad_log(NULL))
3183 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
3184 data ? data : US"", data ? US": " : US"", errmess);
3186 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
3195 /*************************************************
3196 * Send SMTP response, possibly multiline *
3197 *************************************************/
3199 /* There are, it seems, broken clients out there that cannot handle multiline
3200 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3201 output nothing for non-final calls, and only the first line for anything else.
3204 code SMTP code, may involve extended status codes
3205 codelen length of smtp code; if > 4 there's an ESC
3206 final FALSE if the last line isn't the final line
3207 msg message text, possibly containing newlines
3213 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
3218 if (!final && f.no_multiline_responses) return;
3223 esclen = codelen - 4;
3226 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3227 have had the same. Note: this code is also present in smtp_printf(). It would
3228 be tidier to have it only in one place, but when it was added, it was easier to
3229 do it that way, so as not to have to mess with the code for the RCPT command,
3230 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3232 if (fl.rcpt_in_progress)
3234 if (rcpt_smtp_response == NULL)
3235 rcpt_smtp_response = string_copy(msg);
3236 else if (fl.rcpt_smtp_response_same &&
3237 Ustrcmp(rcpt_smtp_response, msg) != 0)
3238 fl.rcpt_smtp_response_same = FALSE;
3239 fl.rcpt_in_progress = FALSE;
3242 /* Now output the message, splitting it up into multiple lines if necessary.
3243 We only handle pipelining these responses as far as nonfinal/final groups,
3244 not the whole MAIL/RCPT/DATA response set. */
3248 uschar *nl = Ustrchr(msg, '\n');
3251 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3254 else if (nl[1] == 0 || f.no_multiline_responses)
3256 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3257 (int)(nl - msg), msg);
3262 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3264 Uskip_whitespace(&msg);
3272 /*************************************************
3273 * Parse user SMTP message *
3274 *************************************************/
3276 /* This function allows for user messages overriding the response code details
3277 by providing a suitable response code string at the start of the message
3278 user_msg. Check the message for starting with a response code and optionally an
3279 extended status code. If found, check that the first digit is valid, and if so,
3280 change the code pointer and length to use the replacement. An invalid code
3281 causes a panic log; in this case, if the log messages is the same as the user
3282 message, we must also adjust the value of the log message to show the code that
3283 is actually going to be used (the original one).
3285 This function is global because it is called from receive.c as well as within
3288 Note that the code length returned includes the terminating whitespace
3289 character, which is always included in the regex match.
3292 code SMTP code, may involve extended status codes
3293 codelen length of smtp code; if > 4 there's an ESC
3295 log_msg optional log message, to be adjusted with the new SMTP code
3296 check_valid if true, verify the response code
3302 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3308 if (!msg || !*msg) return;
3310 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3311 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3313 if (check_valid && (*msg)[0] != (*code)[0])
3315 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3316 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3317 if (log_msg != NULL && *log_msg == *msg)
3318 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3323 *codelen = ovector[1]; /* Includes final space */
3325 *msg += ovector[1]; /* Chop the code off the message */
3332 /*************************************************
3333 * Handle an ACL failure *
3334 *************************************************/
3336 /* This function is called when acl_check() fails. As well as calls from within
3337 this module, it is called from receive.c for an ACL after DATA. It sorts out
3338 logging the incident, and sends the error response. A message containing
3339 newlines is turned into a multiline SMTP response, but for logging, only the
3342 There's a table of default permanent failure response codes to use in
3343 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3344 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3345 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3346 state, because there are broken clients that try VRFY before RCPT. A 5xx
3347 response should be given only when the address is positively known to be
3348 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3349 no explicit code, but if there is one we let it know best.
3350 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3352 From Exim 4.63, it is possible to override the response code details by
3353 providing a suitable response code string at the start of the message provided
3354 in user_msg. The code's first digit is checked for validity.
3357 where where the ACL was called from
3359 user_msg a message that can be included in an SMTP response
3360 log_msg a message for logging
3362 Returns: 0 in most cases
3363 2 if the failure code was FAIL_DROP, in which case the
3364 SMTP connection should be dropped (this value fits with the
3365 "done" variable in smtp_setup_msg() below)
3369 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3371 BOOL drop = rc == FAIL_DROP;
3375 uschar *sender_info = US"";
3377 #ifdef WITH_CONTENT_SCAN
3378 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3380 where == ACL_WHERE_PREDATA ? US"DATA" :
3381 where == ACL_WHERE_DATA ? US"after DATA" :
3382 #ifndef DISABLE_PRDR
3383 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3386 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3387 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3389 if (drop) rc = FAIL;
3391 /* Set the default SMTP code, and allow a user message to change it. */
3393 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3394 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3395 where != ACL_WHERE_VRFY);
3397 /* We used to have sender_address here; however, there was a bug that was not
3398 updating sender_address after a rewrite during a verify. When this bug was
3399 fixed, sender_address at this point became the rewritten address. I'm not sure
3400 this is what should be logged, so I've changed to logging the unrewritten
3401 address to retain backward compatibility. */
3403 #ifndef WITH_CONTENT_SCAN
3404 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3406 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3409 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3410 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3411 sender_host_authenticated ? US" A=" : US"",
3412 sender_host_authenticated ? sender_host_authenticated : US"",
3413 sender_host_authenticated && authenticated_id ? US":" : US"",
3414 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3418 /* If there's been a sender verification failure with a specific message, and
3419 we have not sent a response about it yet, do so now, as a preliminary line for
3420 failures, but not defers. However, always log it for defer, and log it for fail
3421 unless the sender_verify_fail log selector has been turned off. */
3423 if (sender_verified_failed &&
3424 !testflag(sender_verified_failed, af_sverify_told))
3426 BOOL save_rcpt_in_progress = fl.rcpt_in_progress;
3427 fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3429 setflag(sender_verified_failed, af_sverify_told);
3431 if (rc != FAIL || LOGGING(sender_verify_fail))
3432 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3433 host_and_ident(TRUE),
3434 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3435 sender_verified_failed->address,
3436 (sender_verified_failed->message == NULL)? US"" :
3437 string_sprintf(": %s", sender_verified_failed->message));
3439 if (rc == FAIL && sender_verified_failed->user_message)
3440 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3441 testflag(sender_verified_failed, af_verify_pmfail)?
3442 "Postmaster verification failed while checking <%s>\n%s\n"
3443 "Several RFCs state that you are required to have a postmaster\n"
3444 "mailbox for each mail domain. This host does not accept mail\n"
3445 "from domains whose servers reject the postmaster address."
3447 testflag(sender_verified_failed, af_verify_nsfail)?
3448 "Callback setup failed while verifying <%s>\n%s\n"
3449 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3450 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3451 "RFC requirements, and stops you from receiving standard bounce\n"
3452 "messages. This host does not accept mail from domains whose servers\n"
3455 "Verification failed for <%s>\n%s",
3456 sender_verified_failed->address,
3457 sender_verified_failed->user_message));
3459 fl.rcpt_in_progress = save_rcpt_in_progress;
3462 /* Sort out text for logging */
3464 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3465 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3467 /* Send permanent failure response to the command, but the code used isn't
3468 always a 5xx one - see comments at the start of this function. If the original
3469 rc was FAIL_DROP we drop the connection and yield 2. */
3472 smtp_respond(smtp_code, codelen, TRUE,
3473 user_msg ? user_msg : US"Administrative prohibition");
3475 /* Send temporary failure response to the command. Don't give any details,
3476 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3477 verb, and for a header verify when smtp_return_error_details is set.
3479 This conditional logic is all somewhat of a mess because of the odd
3480 interactions between temp_details and return_error_details. One day it should
3481 be re-implemented in a tidier fashion. */
3484 if (f.acl_temp_details && user_msg)
3486 if ( smtp_return_error_details
3487 && sender_verified_failed
3488 && sender_verified_failed->message
3490 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3492 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3495 smtp_respond(smtp_code, codelen, TRUE,
3496 US"Temporary local problem - please try later");
3498 /* Log the incident to the logs that are specified by log_reject_target
3499 (default main, reject). This can be empty to suppress logging of rejections. If
3500 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3501 is closing if required and return 2. */
3503 if (log_reject_target != 0)
3506 gstring * g = s_tlslog(NULL);
3507 uschar * tls = string_from_gstring(g);
3508 if (!tls) tls = US"";
3510 uschar * tls = US"";
3512 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3513 log_reject_target, "%s%s%s %s%srejected %s%s",
3514 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3515 host_and_ident(TRUE),
3518 rc == FAIL ? US"" : US"temporarily ",
3522 if (!drop) return 0;
3524 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3525 smtp_get_connection_info());
3527 /* Run the not-quit ACL, but without any custom messages. This should not be a
3528 problem, because we get here only if some other ACL has issued "drop", and
3529 in that case, *its* custom messages will have been used above. */
3531 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3538 /*************************************************
3539 * Handle SMTP exit when QUIT is not given *
3540 *************************************************/
3542 /* This function provides a logging/statistics hook for when an SMTP connection
3543 is dropped on the floor or the other end goes away. It's a global function
3544 because it's called from receive.c as well as this module. As well as running
3545 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3546 response, either with a custom message from the ACL, or using a default. There
3547 is one case, however, when no message is output - after "drop". In that case,
3548 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3549 passed to this function.
3551 In case things go wrong while processing this function, causing an error that
3552 may re-enter this function, there is a recursion check.
3555 reason What $smtp_notquit_reason will be set to in the ACL;
3556 if NULL, the ACL is not run
3557 code The error code to return as part of the response
3558 defaultrespond The default message if there's no user_msg
3564 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3567 uschar *user_msg = NULL;
3568 uschar *log_msg = NULL;
3570 /* Check for recursive call */
3572 if (fl.smtp_exit_function_called)
3574 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3578 fl.smtp_exit_function_called = TRUE;
3580 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3582 if (acl_smtp_notquit && reason)
3584 smtp_notquit_reason = reason;
3585 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3586 &log_msg)) == ERROR)
3587 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3591 /* If the connection was dropped, we certainly are no longer talking TLS */
3592 tls_in.active.sock = -1;
3594 /* Write an SMTP response if we are expected to give one. As the default
3595 responses are all internal, they should be reasonable size. */
3597 if (code && defaultrespond)
3600 smtp_respond(code, 3, TRUE, user_msg);
3606 va_start(ap, defaultrespond);
3607 g = string_vformat(NULL, SVFMT_EXTEND|SVFMT_REBUFFER, CS defaultrespond, ap);
3609 smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g));
3618 /*************************************************
3619 * Verify HELO argument *
3620 *************************************************/
3622 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3623 matched. It is also called from ACL processing if verify = helo is used and
3624 verification was not previously tried (i.e. helo_try_verify_hosts was not
3625 matched). The result of its processing is to set helo_verified and
3626 helo_verify_failed. These variables should both be FALSE for this function to
3629 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3630 for IPv6 ::ffff: literals.
3633 Returns: TRUE if testing was completed;
3634 FALSE on a temporary failure
3638 smtp_verify_helo(void)
3642 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3645 if (sender_helo_name == NULL)
3647 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3650 /* Deal with the case of -bs without an IP address */
3652 else if (sender_host_address == NULL)
3654 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3655 f.helo_verified = TRUE;
3658 /* Deal with the more common case when there is a sending IP address */
3660 else if (sender_helo_name[0] == '[')
3662 f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3663 Ustrlen(sender_host_address)) == 0;
3666 if (!f.helo_verified)
3668 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3669 f.helo_verified = Ustrncmp(sender_helo_name + 1,
3670 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3675 { if (f.helo_verified) debug_printf("matched host address\n"); }
3678 /* Do a reverse lookup if one hasn't already given a positive or negative
3679 response. If that fails, or the name doesn't match, try checking with a forward
3684 if (sender_host_name == NULL && !host_lookup_failed)
3685 yield = host_name_lookup() != DEFER;
3687 /* If a host name is known, check it and all its aliases. */
3689 if (sender_host_name)
3690 if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3692 sender_helo_dnssec = sender_host_dnssec;
3693 HDEBUG(D_receive) debug_printf("matched host name\n");
3697 uschar **aliases = sender_host_aliases;
3699 if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3701 sender_helo_dnssec = sender_host_dnssec;
3705 HDEBUG(D_receive) if (f.helo_verified)
3706 debug_printf("matched alias %s\n", *(--aliases));
3709 /* Final attempt: try a forward lookup of the helo name */
3711 if (!f.helo_verified)
3715 {.name = sender_helo_name, .address = NULL, .mx = MX_NONE, .next = NULL};
3717 {.request = US"*", .require = US""};
3719 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3721 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
3722 NULL, NULL, NULL, &d, NULL, NULL);
3723 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3724 for (host_item * hh = &h; hh; hh = hh->next)
3725 if (Ustrcmp(hh->address, sender_host_address) == 0)
3727 f.helo_verified = TRUE;
3728 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3730 debug_printf("IP address for %s matches calling address\n"
3731 "Forward DNS security status: %sverified\n",
3732 sender_helo_name, sender_helo_dnssec ? "" : "un");
3738 if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */
3745 /*************************************************
3746 * Send user response message *
3747 *************************************************/
3749 /* This function is passed a default response code and a user message. It calls
3750 smtp_message_code() to check and possibly modify the response code, and then
3751 calls smtp_respond() to transmit the response. I put this into a function
3752 just to avoid a lot of repetition.
3755 code the response code
3756 user_msg the user message
3762 smtp_user_msg(uschar *code, uschar *user_msg)
3765 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3766 smtp_respond(code, len, TRUE, user_msg);
3772 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3774 const uschar *set_id = NULL;
3777 /* Run the checking code, passing the remainder of the command line as
3778 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3779 it as the only set numerical variable. The authenticator may set $auth<n>
3780 and also set other numeric variables. The $auth<n> variables are preferred
3781 nowadays; the numerical variables remain for backwards compatibility.
3783 Afterwards, have a go at expanding the set_id string, even if
3784 authentication failed - for bad passwords it can be useful to log the
3785 userid. On success, require set_id to expand and exist, and put it in
3786 authenticated_id. Save this in permanent store, as the working store gets
3787 reset at HELO, RSET, etc. */
3789 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3791 expand_nlength[0] = 0; /* $0 contains nothing */
3793 rc = (au->info->servercode)(au, smtp_cmd_data);
3794 if (au->set_id) set_id = expand_string(au->set_id);
3795 expand_nmax = -1; /* Reset numeric variables */
3796 for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3798 /* The value of authenticated_id is stored in the spool file and printed in
3799 log lines. It must not contain binary zeros or newline characters. In
3800 normal use, it never will, but when playing around or testing, this error
3801 can (did) happen. To guard against this, ensure that the id contains only
3802 printing characters. */
3804 if (set_id) set_id = string_printing(set_id);
3806 /* For the non-OK cases, set up additional logging data if set_id
3810 set_id = set_id && *set_id
3811 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3813 /* Switch on the result */
3818 if (!au->set_id || set_id) /* Complete success */
3820 if (set_id) authenticated_id = string_copy_perm(set_id, TRUE);
3821 sender_host_authenticated = au->name;
3822 sender_host_auth_pubname = au->public_name;
3823 authentication_failed = FALSE;
3824 authenticated_fail_id = NULL; /* Impossible to already be set? */
3827 (sender_host_address ? protocols : protocols_local)
3828 [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)];
3829 *s = *ss = US"235 Authentication succeeded";
3830 authenticated_by = au;
3834 /* Authentication succeeded, but we failed to expand the set_id string.
3835 Treat this as a temporary error. */
3837 auth_defer_msg = expand_string_message;
3841 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3842 *s = string_sprintf("435 Unable to authenticate at present%s",
3843 auth_defer_user_msg);
3844 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3845 set_id, auth_defer_msg);
3849 *s = *ss = US"501 Invalid base64 data";
3853 *s = *ss = US"501 Authentication cancelled";
3857 *s = *ss = US"553 Initial data not expected";
3861 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3862 *s = US"535 Incorrect authentication data";
3863 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3867 if (set_id) authenticated_fail_id = string_copy_perm(set_id, TRUE);
3868 *s = US"435 Internal error";
3869 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3870 "check", set_id, rc);
3882 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3885 if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3887 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3889 rd = Ustrlen(recipient) + 1;
3890 /* deconst ok as *recipient was not const */
3891 *recipient = US rewrite_address_qualify(*recipient, TRUE);
3894 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3896 log_write(L_smtp_syntax_error,
3897 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3898 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3906 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3909 incomplete_transaction_log(US"QUIT");
3912 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3914 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3919 (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_CORK, US &on, sizeof(on));
3923 smtp_respond(US"221", 3, TRUE, *user_msgp);
3925 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3928 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
3931 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3932 smtp_get_connection_info());
3937 smtp_rset_handler(void)
3940 incomplete_transaction_log(US"RSET");
3941 smtp_printf("250 Reset OK\r\n", FALSE);
3942 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3947 /*************************************************
3948 * Initialize for SMTP incoming message *
3949 *************************************************/
3951 /* This function conducts the initial dialogue at the start of an incoming SMTP
3952 message, and builds a list of recipients. However, if the incoming message
3953 is part of a batch (-bS option) a separate function is called since it would
3954 be messy having tests splattered about all over this function. This function
3955 therefore handles the case where interaction is occurring. The input and output
3956 files are set up in smtp_in and smtp_out.
3958 The global recipients_list is set to point to a vector of recipient_item
3959 blocks, whose number is given by recipients_count. This is extended by the
3960 receive_add_recipient() function. The global variable sender_address is set to
3961 the sender's address. The yield is +1 if a message has been successfully
3962 started, 0 if a QUIT command was encountered or the connection was refused from
3963 the particular host, or -1 if the connection was lost.
3967 Returns: > 0 message successfully started (reached DATA)
3968 = 0 QUIT read or end of file reached or call refused
3973 smtp_setup_msg(void)
3976 BOOL toomany = FALSE;
3977 BOOL discarded = FALSE;
3978 BOOL last_was_rej_mail = FALSE;
3979 BOOL last_was_rcpt = FALSE;
3980 rmark reset_point = store_mark();
3982 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3984 /* Reset for start of new message. We allow one RSET not to be counted as a
3985 nonmail command, for those MTAs that insist on sending it between every
3986 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3987 TLS between messages (an Exim client may do this if it has messages queued up
3988 for the host). Note: we do NOT reset AUTH at this point. */
3990 reset_point = smtp_reset(reset_point);
3991 message_ended = END_NOTSTARTED;
3993 chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3995 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3996 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3997 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3999 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
4002 if (lwr_receive_getc != NULL)
4004 /* This should have already happened, but if we've gotten confused,
4005 force a reset here. */
4006 DEBUG(D_receive) debug_printf("WARNING: smtp_setup_msg had to restore receive functions to lowers\n");
4007 bdat_pop_receive_functions();
4010 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
4012 had_command_sigterm = 0;
4013 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
4015 /* Batched SMTP is handled in a different function. */
4017 if (smtp_batched_input) return smtp_setup_batch_msg();
4019 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
4020 value. The values are 2 larger than the required yield of the function. */
4024 const uschar **argv;
4025 uschar *etrn_command;
4026 uschar *etrn_serialize_key;
4028 uschar *log_msg, *smtp_code;
4029 uschar *user_msg = NULL;
4030 uschar *recipient = NULL;
4031 uschar *hello = NULL;
4033 BOOL was_rej_mail = FALSE;
4034 BOOL was_rcpt = FALSE;
4035 void (*oldsignal)(int);
4037 int start, end, sender_domain, recipient_domain;
4040 uschar *orcpt = NULL;
4045 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
4046 if ( tls_in.active.sock >= 0
4048 && tls_in.certificate_verified
4049 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
4052 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
4054 for (auth_instance * au = auths; au; au = au->next)
4055 if (strcmpic(US"tls", au->driver_name) == 0)
4058 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4059 &user_msg, &log_msg)) != OK
4061 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4064 smtp_cmd_data = NULL;
4066 if (smtp_in_auth(au, &s, &ss) == OK)
4067 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
4069 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
4077 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
4078 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
4079 US &off, sizeof(off));
4082 switch(smtp_read_command(
4083 #ifndef DISABLE_PIPE_CONNECT
4084 !fl.pipe_connect_acceptable,
4088 GETC_BUFFER_UNLIMITED))
4090 /* The AUTH command is not permitted to occur inside a transaction, and may
4091 occur successfully only once per connection. Actually, that isn't quite
4092 true. When TLS is started, all previous information about a connection must
4093 be discarded, so a new AUTH is permitted at that time.
4095 AUTH may only be used when it has been advertised. However, it seems that
4096 there are clients that send AUTH when it hasn't been advertised, some of
4097 them even doing this after HELO. And there are MTAs that accept this. Sigh.
4098 So there's a get-out that allows this to happen.
4100 AUTH is initially labelled as a "nonmail command" so that one occurrence
4101 doesn't get counted. We change the label here so that multiple failing
4102 AUTHS will eventually hit the nonmail threshold. */
4106 authentication_failed = TRUE;
4107 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
4109 if (!fl.auth_advertised && !f.allow_auth_unadvertised)
4111 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4112 US"AUTH command used when not advertised");
4115 if (sender_host_authenticated)
4117 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4118 US"already authenticated");
4123 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4124 US"not permitted in mail transaction");
4131 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
4132 &user_msg, &log_msg)) != OK
4135 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
4139 /* Find the name of the requested authentication mechanism. */
4142 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
4144 if (!isalnum(c) && c != '-' && c != '_')
4146 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4147 US"invalid character in authentication mechanism name");
4153 /* If not at the end of the line, we must be at white space. Terminate the
4154 name and move the pointer on to any data that may be present. */
4156 if (*smtp_cmd_data != 0)
4158 *smtp_cmd_data++ = 0;
4159 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
4162 /* Search for an authentication mechanism which is configured for use
4163 as a server and which has been advertised (unless, sigh, allow_auth_
4164 unadvertised is set). */
4168 for (au = auths; au; au = au->next)
4169 if (strcmpic(s, au->public_name) == 0 && au->server &&
4170 (au->advertised || f.allow_auth_unadvertised))
4175 c = smtp_in_auth(au, &s, &ss);
4177 smtp_printf("%s\r\n", FALSE, s);
4179 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
4180 au->name, host_and_ident(FALSE), ss);
4183 done = synprot_error(L_smtp_protocol_error, 504, NULL,
4184 string_sprintf("%s authentication mechanism not supported", s));
4187 break; /* AUTH_CMD */
4189 /* The HELO/EHLO commands are permitted to appear in the middle of a
4190 session as well as at the beginning. They have the effect of a reset in
4191 addition to their other functions. Their absence at the start cannot be
4192 taken to be an error.
4196 If the EHLO command is not acceptable to the SMTP server, 501, 500,
4197 or 502 failure replies MUST be returned as appropriate. The SMTP
4198 server MUST stay in the same state after transmitting these replies
4199 that it was in before the EHLO was received.
4201 Therefore, we do not do the reset until after checking the command for
4202 acceptability. This change was made for Exim release 4.11. Previously
4203 it did the reset first. */
4216 HELO_EHLO: /* Common code for HELO and EHLO */
4217 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
4218 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
4220 /* Reject the HELO if its argument was invalid or non-existent. A
4221 successful check causes the argument to be saved in malloc store. */
4223 if (!check_helo(smtp_cmd_data))
4225 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
4227 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
4228 "invalid argument(s): %s", hello, host_and_ident(FALSE),
4229 *smtp_cmd_argument == 0 ? US"(no argument given)" :
4230 string_printing(smtp_cmd_argument));
4232 if (++synprot_error_count > smtp_max_synprot_errors)
4234 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
4235 "syntax or protocol errors (last command was \"%s\", %s)",
4236 host_and_ident(FALSE), string_printing(smtp_cmd_buffer),
4237 string_from_gstring(s_connhad_log(NULL))
4245 /* If sender_host_unknown is true, we have got here via the -bs interface,
4246 not called from inetd. Otherwise, we are running an IP connection and the
4247 host address will be set. If the helo name is the primary name of this
4248 host and we haven't done a reverse lookup, force one now. If helo_required
4249 is set, ensure that the HELO name matches the actual host. If helo_verify
4250 is set, do the same check, but softly. */
4252 if (!f.sender_host_unknown)
4254 BOOL old_helo_verified = f.helo_verified;
4255 uschar *p = smtp_cmd_data;
4257 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4260 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4261 because otherwise the log can be confusing. */
4263 if ( !sender_host_name
4264 && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4265 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
4266 (void)host_name_lookup();
4268 /* Rebuild the fullhost info to include the HELO name (and the real name
4269 if it was looked up.) */
4271 host_build_sender_fullhost(); /* Rebuild */
4272 set_process_info("handling%s incoming connection from %s",
4273 tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE));
4275 /* Verify if configured. This doesn't give much security, but it does
4276 make some people happy to be able to do it. If helo_required is set,
4277 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4278 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4279 now obsolescent, since the verification can now be requested selectively
4282 f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE;
4283 if (fl.helo_required || fl.helo_verify)
4285 BOOL tempfail = !smtp_verify_helo();
4286 if (!f.helo_verified)
4288 if (fl.helo_required)
4290 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4291 tempfail? 451 : 550, hello);
4292 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4293 tempfail? "temporarily " : "",
4294 hello, sender_helo_name, host_and_ident(FALSE));
4295 f.helo_verified = old_helo_verified;
4296 break; /* End of HELO/EHLO processing */
4298 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4299 "helo_try_verify_hosts\n", hello);
4305 /* set up SPF context */
4306 spf_conn_init(sender_helo_name, sender_host_address);
4309 /* Apply an ACL check if one is defined; afterwards, recheck
4310 synchronization in case the client started sending in a delay. */
4313 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4314 &user_msg, &log_msg)) != OK)
4316 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4317 sender_helo_name = NULL;
4318 host_build_sender_fullhost(); /* Rebuild */
4321 #ifndef DISABLE_PIPE_CONNECT
4322 else if (!fl.pipe_connect_acceptable && !check_sync())
4324 else if (!check_sync())
4328 /* Generate an OK reply. The default string includes the ident if present,
4329 and also the IP address if present. Reflecting back the ident is intended
4330 as a deterrent to mail forgers. For maximum efficiency, and also because
4331 some broken systems expect each response to be in a single packet, arrange
4332 that the entire reply is sent in one write(). */
4334 fl.auth_advertised = FALSE;
4335 f.smtp_in_pipelining_advertised = FALSE;
4337 fl.tls_advertised = FALSE;
4339 fl.dsn_advertised = FALSE;
4341 fl.smtputf8_advertised = FALSE;
4344 smtp_code = US"250 "; /* Default response code plus space*/
4347 /* sender_host_name below will be tainted, so save on copy when we hit it */
4348 g = string_get_tainted(24, TRUE);
4349 g = string_fmt_append(g, "%.3s %s Hello %s%s%s",
4351 smtp_active_hostname,
4352 sender_ident ? sender_ident : US"",
4353 sender_ident ? US" at " : US"",
4354 sender_host_name ? sender_host_name : sender_helo_name);
4356 if (sender_host_address)
4357 g = string_fmt_append(g, " [%s]", sender_host_address);
4360 /* A user-supplied EHLO greeting may not contain more than one line. Note
4361 that the code returned by smtp_message_code() includes the terminating
4362 whitespace character. */
4368 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
4369 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
4370 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
4372 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
4373 "newlines: message truncated: %s", string_printing(s));
4376 g = string_cat(NULL, s);
4379 g = string_catn(g, US"\r\n", 2);
4381 /* If we received EHLO, we must create a multiline response which includes
4382 the functions supported. */
4388 /* I'm not entirely happy with this, as an MTA is supposed to check
4389 that it has enough room to accept a message of maximum size before
4390 it sends this. However, there seems little point in not sending it.
4391 The actual size check happens later at MAIL FROM time. By postponing it
4392 till then, VRFY and EXPN can be used after EHLO when space is short. */
4394 if (thismessage_size_limit > 0)
4395 g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code,
4396 thismessage_size_limit);
4399 g = string_catn(g, smtp_code, 3);
4400 g = string_catn(g, US"-SIZE\r\n", 7);
4403 /* Exim does not do protocol conversion or data conversion. It is 8-bit
4404 clean; if it has an 8-bit character in its hand, it just sends it. It
4405 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
4406 However, some users want this option simply in order to stop MUAs
4407 mangling messages that contain top-bit-set characters. It is therefore
4408 provided as an option. */
4410 if (accept_8bitmime)
4412 g = string_catn(g, smtp_code, 3);
4413 g = string_catn(g, US"-8BITMIME\r\n", 11);
4416 /* Advertise DSN support if configured to do so. */
4417 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
4419 g = string_catn(g, smtp_code, 3);
4420 g = string_catn(g, US"-DSN\r\n", 6);
4421 fl.dsn_advertised = TRUE;
4424 /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is
4425 permitted to issue them; a check is made when any host actually tries. */
4429 g = string_catn(g, smtp_code, 3);
4430 g = string_catn(g, US"-ETRN\r\n", 7);
4434 g = string_catn(g, smtp_code, 3);
4435 g = string_catn(g, US"-VRFY\r\n", 7);
4439 g = string_catn(g, smtp_code, 3);
4440 g = string_catn(g, US"-EXPN\r\n", 7);
4443 /* Exim is quite happy with pipelining, so let the other end know that
4444 it is safe to use it, unless advertising is disabled. */
4446 if ( f.pipelining_enable
4447 && verify_check_host(&pipelining_advertise_hosts) == OK)
4449 g = string_catn(g, smtp_code, 3);
4450 g = string_catn(g, US"-PIPELINING\r\n", 13);
4451 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
4452 f.smtp_in_pipelining_advertised = TRUE;
4454 #ifndef DISABLE_PIPE_CONNECT
4455 if (fl.pipe_connect_acceptable)
4457 f.smtp_in_early_pipe_advertised = TRUE;
4458 g = string_catn(g, smtp_code, 3);
4459 g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3);
4465 /* If any server authentication mechanisms are configured, advertise
4466 them if the current host is in auth_advertise_hosts. The problem with
4467 advertising always is that some clients then require users to
4468 authenticate (and aren't configurable otherwise) even though it may not
4469 be necessary (e.g. if the host is in host_accept_relay).
4471 RFC 2222 states that SASL mechanism names contain only upper case
4472 letters, so output the names in upper case, though we actually recognize
4473 them in either case in the AUTH command. */
4477 && !sender_host_authenticated
4479 && verify_check_host(&auth_advertise_hosts) == OK
4483 for (auth_instance * au = auths; au; au = au->next)
4485 au->advertised = FALSE;
4488 DEBUG(D_auth+D_expand) debug_printf_indent(
4489 "Evaluating advertise_condition for %s %s athenticator\n",
4490 au->name, au->public_name);
4491 if ( !au->advertise_condition
4492 || expand_check_condition(au->advertise_condition, au->name,
4499 g = string_catn(g, smtp_code, 3);
4500 g = string_catn(g, US"-AUTH", 5);
4502 fl.auth_advertised = TRUE;
4505 g = string_catn(g, US" ", 1);
4506 g = string_cat (g, au->public_name);
4507 while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]);
4508 au->advertised = TRUE;
4513 if (!first) g = string_catn(g, US"\r\n", 2);
4516 /* RFC 3030 CHUNKING */
4518 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
4520 g = string_catn(g, smtp_code, 3);
4521 g = string_catn(g, US"-CHUNKING\r\n", 11);
4522 f.chunking_offered = TRUE;
4523 chunking_state = CHUNKING_OFFERED;
4526 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
4527 if it has been included in the binary, and the host matches
4528 tls_advertise_hosts. We must *not* advertise if we are already in a
4529 secure connection. */
4532 if (tls_in.active.sock < 0 &&
4533 verify_check_host(&tls_advertise_hosts) != FAIL)
4535 g = string_catn(g, smtp_code, 3);
4536 g = string_catn(g, US"-STARTTLS\r\n", 11);
4537 fl.tls_advertised = TRUE;
4541 #ifndef DISABLE_PRDR
4542 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
4545 g = string_catn(g, smtp_code, 3);
4546 g = string_catn(g, US"-PRDR\r\n", 7);
4551 if ( accept_8bitmime
4552 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
4554 g = string_catn(g, smtp_code, 3);
4555 g = string_catn(g, US"-SMTPUTF8\r\n", 11);
4556 fl.smtputf8_advertised = TRUE;
4560 /* Finish off the multiline reply with one that is always available. */
4562 g = string_catn(g, smtp_code, 3);
4563 g = string_catn(g, US" HELP\r\n", 7);
4566 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4570 if (tls_in.active.sock >= 0)
4571 (void)tls_write(NULL, g->s, g->ptr,
4572 # ifndef DISABLE_PIPE_CONNECT
4573 fl.pipe_connect_acceptable && pipeline_connect_sends());
4581 int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */
4587 (void) string_from_gstring(g);
4588 while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */
4589 memmove(cr, cr + 1, (g->ptr--) - (cr - g->s));
4590 debug_printf("SMTP>> %s", g->s);
4592 fl.helo_seen = TRUE;
4594 /* Reset the protocol and the state, abandoning any previous message. */
4596 (sender_host_address ? protocols : protocols_local)
4598 ? pextend + (sender_host_authenticated ? pauthed : 0)
4600 + (tls_in.active.sock >= 0 ? pcrpted : 0)
4602 cancel_cutthrough_connection(TRUE, US"sent EHLO response");
4603 reset_point = smtp_reset(reset_point);
4605 break; /* HELO/EHLO */
4608 /* The MAIL command requires an address as an operand. All we do
4609 here is to parse it for syntactic correctness. The form "<>" is
4610 a special case which converts into an empty string. The start/end
4611 pointers in the original are not used further for this address, as
4612 it is the canonical extracted address which is all that is kept. */
4616 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4617 was_rej_mail = TRUE; /* Reset if accepted */
4618 env_mail_type_t * mail_args; /* Sanity check & validate args */
4620 if (fl.helo_required && !fl.helo_seen)
4622 smtp_printf("503 HELO or EHLO required\r\n", FALSE);
4623 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4624 "HELO/EHLO given", host_and_ident(FALSE));
4630 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4631 US"sender already given");
4635 if (!*smtp_cmd_data)
4637 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4638 US"MAIL must have an address operand");
4642 /* Check to see if the limit for messages per connection would be
4643 exceeded by accepting further messages. */
4645 if (smtp_accept_max_per_connection > 0 &&
4646 smtp_mailcmd_count > smtp_accept_max_per_connection)
4648 smtp_printf("421 too many messages in this connection\r\n", FALSE);
4649 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4650 "messages in one connection", host_and_ident(TRUE));
4654 /* Reset for start of message - even if this is going to fail, we
4655 obviously need to throw away any previous data. */
4657 cancel_cutthrough_connection(TRUE, US"MAIL received");
4658 reset_point = smtp_reset(reset_point);
4660 sender_data = recipient_data = NULL;
4662 /* Loop, checking for ESMTP additions to the MAIL FROM command. */
4664 if (fl.esmtp) for(;;)
4666 uschar *name, *value, *end;
4667 unsigned long int size;
4668 BOOL arg_error = FALSE;
4670 if (!extract_option(&name, &value)) break;
4672 for (mail_args = env_mail_type_list;
4673 mail_args->value != ENV_MAIL_OPT_NULL;
4676 if (strcmpic(name, mail_args->name) == 0)
4678 if (mail_args->need_value && strcmpic(value, US"") == 0)
4681 switch(mail_args->value)
4683 /* Handle SIZE= by reading the value. We don't do the check till later,
4684 in order to be able to log the sender address on failure. */
4685 case ENV_MAIL_OPT_SIZE:
4686 if (((size = Ustrtoul(value, &end, 10)), *end == 0))
4688 if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
4690 message_size = (int)size;
4696 /* If this session was initiated with EHLO and accept_8bitmime is set,
4697 Exim will have indicated that it supports the BODY=8BITMIME option. In
4698 fact, it does not support this according to the RFCs, in that it does not
4699 take any special action for forwarding messages containing 8-bit
4700 characters. That is why accept_8bitmime is not the default setting, but
4701 some sites want the action that is provided. We recognize both "8BITMIME"
4702 and "7BIT" as body types, but take no action. */
4703 case ENV_MAIL_OPT_BODY:
4704 if (accept_8bitmime) {
4705 if (strcmpic(value, US"8BITMIME") == 0)
4707 else if (strcmpic(value, US"7BIT") == 0)
4712 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4713 US"invalid data for BODY");
4716 DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime);
4722 /* Handle the two DSN options, but only if configured to do so (which
4723 will have caused "DSN" to be given in the EHLO response). The code itself
4724 is included only if configured in at build time. */
4726 case ENV_MAIL_OPT_RET:
4727 if (fl.dsn_advertised)
4729 /* Check if RET has already been set */
4732 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4733 US"RET can be specified once only");
4736 dsn_ret = strcmpic(value, US"HDRS") == 0
4738 : strcmpic(value, US"FULL") == 0
4741 DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret);
4742 /* Check for invalid invalid value, and exit with error */
4745 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4746 US"Value for RET is invalid");
4751 case ENV_MAIL_OPT_ENVID:
4752 if (fl.dsn_advertised)
4754 /* Check if the dsn envid has been already set */
4757 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4758 US"ENVID can be specified once only");
4761 dsn_envid = string_copy(value);
4762 DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
4766 /* Handle the AUTH extension. If the value given is not "<>" and either
4767 the ACL says "yes" or there is no ACL but the sending host is
4768 authenticated, we set it up as the authenticated sender. However, if the
4769 authenticator set a condition to be tested, we ignore AUTH on MAIL unless
4770 the condition is met. The value of AUTH is an xtext, which means that +,
4771 = and cntrl chars are coded in hex; however "<>" is unaffected by this
4773 case ENV_MAIL_OPT_AUTH:
4774 if (Ustrcmp(value, "<>") != 0)
4779 if (auth_xtextdecode(value, &authenticated_sender) < 0)
4781 /* Put back terminator overrides for error message */
4784 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4785 US"invalid data for AUTH");
4788 if (!acl_smtp_mailauth)
4790 ignore_msg = US"client not authenticated";
4791 rc = sender_host_authenticated ? OK : FAIL;
4795 ignore_msg = US"rejected by ACL";
4796 rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
4797 &user_msg, &log_msg);
4803 if (authenticated_by == NULL ||
4804 authenticated_by->mail_auth_condition == NULL ||
4805 expand_check_condition(authenticated_by->mail_auth_condition,
4806 authenticated_by->name, US"authenticator"))
4807 break; /* Accept the AUTH */
4809 ignore_msg = US"server_mail_auth_condition failed";
4810 if (authenticated_id != NULL)
4811 ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
4812 ignore_msg, authenticated_id);
4817 authenticated_sender = NULL;
4818 log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
4819 value, host_and_ident(TRUE), ignore_msg);
4822 /* Should only get DEFER or ERROR here. Put back terminator
4823 overrides for error message */
4828 (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
4835 #ifndef DISABLE_PRDR
4836 case ENV_MAIL_OPT_PRDR:
4838 prdr_requested = TRUE;
4843 case ENV_MAIL_OPT_UTF8:
4844 if (!fl.smtputf8_advertised)
4846 done = synprot_error(L_smtp_syntax_error, 501, NULL,
4847 US"SMTPUTF8 used when not advertised");
4851 DEBUG(D_receive) debug_printf("smtputf8 requested\n");
4852 message_smtputf8 = allow_utf8_domains = TRUE;
4853 if (Ustrncmp(received_protocol, US"utf8", 4) != 0)
4855 int old_pool = store_pool;
4856 store_pool = POOL_PERM;
4857 received_protocol = string_sprintf("utf8%s", received_protocol);
4858 store_pool = old_pool;
4863 /* No valid option. Stick back the terminator characters and break
4864 the loop. Do the name-terminator second as extract_option sets
4865 value==name when it found no equal-sign.
4866 An error for a malformed address will occur. */
4867 case ENV_MAIL_OPT_NULL:
4875 /* Break out of for loop if switch() had bad argument or
4876 when start of the email address is reached */
4877 if (arg_error) break;
4880 /* If we have passed the threshold for rate limiting, apply the current
4881 delay, and update it for next time, provided this is a limited host. */
4883 if (smtp_mailcmd_count > smtp_rlm_threshold &&
4884 verify_check_host(&smtp_ratelimit_hosts) == OK)
4886 DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n",
4887 smtp_delay_mail/1000.0);
4888 millisleep((int)smtp_delay_mail);
4889 smtp_delay_mail *= smtp_rlm_factor;
4890 if (smtp_delay_mail > (double)smtp_rlm_limit)
4891 smtp_delay_mail = (double)smtp_rlm_limit;
4894 /* Now extract the address, first applying any SMTP-time rewriting. The
4895 TRUE flag allows "<>" as a sender address. */
4897 raw_sender = rewrite_existflags & rewrite_smtp
4898 /* deconst ok as smtp_cmd_data was not const */
4899 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
4900 global_rewrite_rules)
4904 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
4909 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
4913 sender_address = raw_sender;
4915 /* If there is a configured size limit for mail, check that this message
4916 doesn't exceed it. The check is postponed to this point so that the sender
4919 if (thismessage_size_limit > 0 && message_size > thismessage_size_limit)
4921 smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE);
4922 log_write(L_size_reject,
4923 LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: "
4924 "message too big: size%s=%d max=%d",
4926 host_and_ident(TRUE),
4927 (message_size == INT_MAX)? ">" : "",
4929 thismessage_size_limit);
4930 sender_address = NULL;
4934 /* Check there is enough space on the disk unless configured not to.
4935 When smtp_check_spool_space is set, the check is for thismessage_size_limit
4936 plus the current message - i.e. we accept the message only if it won't
4937 reduce the space below the threshold. Add 5000 to the size to allow for
4938 overheads such as the Received: line and storing of recipients, etc.
4939 By putting the check here, even when SIZE is not given, it allow VRFY
4940 and EXPN etc. to be used when space is short. */
4942 if (!receive_check_fs(
4943 smtp_check_spool_space && message_size >= 0
4944 ? message_size + 5000 : 0))
4946 smtp_printf("452 Space shortage, please try later\r\n", FALSE);
4947 sender_address = NULL;
4951 /* If sender_address is unqualified, reject it, unless this is a locally
4952 generated message, or the sending host or net is permitted to send
4953 unqualified addresses - typically local machines behaving as MUAs -
4954 in which case just qualify the address. The flag is set above at the start
4955 of the SMTP connection. */
4957 if (!sender_domain && *sender_address)
4958 if (f.allow_unqualified_sender)
4960 sender_domain = Ustrlen(sender_address) + 1;
4961 /* deconst ok as sender_address was not const */
4962 sender_address = US rewrite_address_qualify(sender_address, FALSE);
4963 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
4968 smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE,
4970 log_write(L_smtp_syntax_error,
4971 LOG_MAIN|LOG_REJECT,
4972 "unqualified sender rejected: <%s> %s%s",
4974 host_and_ident(TRUE),
4976 sender_address = NULL;
4980 /* Apply an ACL check if one is defined, before responding. Afterwards,
4981 when pipelining is not advertised, do another sync check in case the ACL
4982 delayed and the client started sending in the meantime. */
4986 rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
4987 if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync())
4993 if (rc == OK || rc == DISCARD)
4995 BOOL more = pipeline_response();
4998 smtp_printf("%s%s%s", more, US"250 OK",
4999 #ifndef DISABLE_PRDR
5000 prdr_requested ? US", PRDR Requested" : US"",
5007 #ifndef DISABLE_PRDR
5009 user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested");
5011 smtp_user_msg(US"250", user_msg);
5013 smtp_delay_rcpt = smtp_rlr_base;
5014 f.recipients_discarded = (rc == DISCARD);
5015 was_rej_mail = FALSE;
5019 done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg);
5020 sender_address = NULL;
5025 /* The RCPT command requires an address as an operand. There may be any
5026 number of RCPT commands, specifying multiple recipients. We build them all
5027 into a data structure. The start/end values given by parse_extract_address
5028 are not used, as we keep only the extracted address. */
5032 /* We got really to many recipients. A check against configured
5033 limits is done later */
5034 if (rcpt_count < 0 || rcpt_count >= INT_MAX/2)
5035 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", rcpt_count);
5037 was_rcpt = fl.rcpt_in_progress = TRUE;
5039 /* There must be a sender address; if the sender was rejected and
5040 pipelining was advertised, we assume the client was pipelining, and do not
5041 count this as a protocol error. Reset was_rej_mail so that further RCPTs
5042 get the same treatment. */
5044 if (sender_address == NULL)
5046 if (f.smtp_in_pipelining_advertised && last_was_rej_mail)
5048 smtp_printf("503 sender not yet given\r\n", FALSE);
5049 was_rej_mail = TRUE;
5053 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5054 US"sender not yet given");
5055 was_rcpt = FALSE; /* Not a valid RCPT */
5061 /* Check for an operand */
5063 if (smtp_cmd_data[0] == 0)
5065 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5066 US"RCPT must have an address operand");
5071 /* Set the DSN flags orcpt and dsn_flags from the session*/
5075 if (fl.esmtp) for(;;)
5077 uschar *name, *value;
5079 if (!extract_option(&name, &value))
5082 if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0)
5084 /* Check whether orcpt has been already set */
5087 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5088 US"ORCPT can be specified once only");
5091 orcpt = string_copy(value);
5092 DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt);
5095 else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0)
5097 /* Check if the notify flags have been already set */
5100 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5101 US"NOTIFY can be specified once only");
5104 if (strcmpic(value, US"NEVER") == 0)
5105 dsn_flags |= rf_notify_never;
5112 while (*pp != 0 && *pp != ',') pp++;
5113 if (*pp == ',') *pp++ = 0;
5114 if (strcmpic(p, US"SUCCESS") == 0)
5116 DEBUG(D_receive) debug_printf("DSN: Setting notify success\n");
5117 dsn_flags |= rf_notify_success;
5119 else if (strcmpic(p, US"FAILURE") == 0)
5121 DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n");
5122 dsn_flags |= rf_notify_failure;
5124 else if (strcmpic(p, US"DELAY") == 0)
5126 DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n");
5127 dsn_flags |= rf_notify_delay;
5131 /* Catch any strange values */
5132 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5133 US"Invalid value for NOTIFY parameter");
5138 DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags);
5142 /* Unknown option. Stick back the terminator characters and break
5143 the loop. An error for a malformed address will occur. */
5147 DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value);
5154 /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
5155 as a recipient address */
5157 recipient = rewrite_existflags & rewrite_smtp
5158 /* deconst ok as smtp_cmd_data was not const */
5159 ? US rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
5160 global_rewrite_rules)
5163 if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end,
5164 &recipient_domain, FALSE)))
5166 done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
5171 /* If the recipient address is unqualified, reject it, unless this is a
5172 locally generated message. However, unqualified addresses are permitted
5173 from a configured list of hosts and nets - typically when behaving as
5174 MUAs rather than MTAs. Sad that SMTP is used for both types of traffic,
5175 really. The flag is set at the start of the SMTP connection.
5177 RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always
5178 assumed this meant "reserved local part", but the revision of RFC 821 and
5179 friends now makes it absolutely clear that it means *mailbox*. Consequently
5180 we must always qualify this address, regardless. */
5182 if (!recipient_domain)
5183 if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data,
5190 /* Check maximum allowed */
5192 if (rcpt_count+1 < 0 || rcpt_count > recipients_max && recipients_max > 0)
5194 if (recipients_max_reject)
5197 smtp_printf("552 too many recipients\r\n", FALSE);
5199 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message "
5200 "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE));
5205 smtp_printf("452 too many recipients\r\n", FALSE);
5207 log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess "
5208 "temporarily rejected: sender=<%s> %s", sender_address,
5209 host_and_ident(TRUE));
5216 /* If we have passed the threshold for rate limiting, apply the current
5217 delay, and update it for next time, provided this is a limited host. */
5219 if (rcpt_count > smtp_rlr_threshold &&
5220 verify_check_host(&smtp_ratelimit_hosts) == OK)
5222 DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n",
5223 smtp_delay_rcpt/1000.0);
5224 millisleep((int)smtp_delay_rcpt);
5225 smtp_delay_rcpt *= smtp_rlr_factor;
5226 if (smtp_delay_rcpt > (double)smtp_rlr_limit)
5227 smtp_delay_rcpt = (double)smtp_rlr_limit;
5230 /* If the MAIL ACL discarded all the recipients, we bypass ACL checking
5231 for them. Otherwise, check the access control list for this recipient. As
5232 there may be a delay in this, re-check for a synchronization error
5233 afterwards, unless pipelining was advertised. */
5235 if (f.recipients_discarded)
5238 if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
5240 && !f.smtp_in_pipelining_advertised && !check_sync())
5243 /* The ACL was happy */
5247 BOOL more = pipeline_response();
5250 smtp_user_msg(US"250", user_msg);
5252 smtp_printf("250 Accepted\r\n", more);
5253 receive_add_recipient(recipient, -1);
5255 /* Set the dsn flags in the recipients_list */
5256 recipients_list[recipients_count-1].orcpt = orcpt;
5257 recipients_list[recipients_count-1].dsn_flags = dsn_flags;
5259 /* DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n",
5260 recipients_list[recipients_count-1].orcpt,
5261 recipients_list[recipients_count-1].dsn_flags); */
5264 /* The recipient was discarded */
5266 else if (rc == DISCARD)
5269 smtp_user_msg(US"250", user_msg);
5271 smtp_printf("250 Accepted\r\n", FALSE);
5274 log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: "
5275 "discarded by %s ACL%s%s", host_and_ident(TRUE),
5276 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
5277 smtp_cmd_argument, f.recipients_discarded ? "MAIL" : "RCPT",
5278 log_msg ? US": " : US"", log_msg ? log_msg : US"");
5281 /* Either the ACL failed the address, or it was deferred. */
5285 if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++;
5286 done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg);
5291 /* The DATA command is legal only if it follows successful MAIL FROM
5292 and RCPT TO commands. However, if pipelining is advertised, a bad DATA is
5293 not counted as a protocol error if it follows RCPT (which must have been
5294 rejected if there are no recipients.) This function is complete when a
5295 valid DATA command is encountered.
5297 Note concerning the code used: RFC 2821 says this:
5299 - If there was no MAIL, or no RCPT, command, or all such commands
5300 were rejected, the server MAY return a "command out of sequence"
5301 (503) or "no valid recipients" (554) reply in response to the
5304 The example in the pipelining RFC 2920 uses 554, but I use 503 here
5305 because it is the same whether pipelining is in use or not.
5307 If all the RCPT commands that precede DATA provoked the same error message
5308 (often indicating some kind of system error), it is helpful to include it
5309 with the DATA rejection (an idea suggested by Tony Finch). */
5316 if (chunking_state != CHUNKING_OFFERED)
5318 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5319 US"BDAT command used when CHUNKING not advertised");
5323 /* grab size, endmarker */
5325 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
5327 done = synprot_error(L_smtp_protocol_error, 501, NULL,
5328 US"missing size for BDAT command");
5331 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
5332 ? CHUNKING_LAST : CHUNKING_ACTIVE;
5333 chunking_data_left = chunking_datasize;
5334 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
5335 (int)chunking_state, chunking_data_left);
5337 f.bdat_readers_wanted = TRUE; /* FIXME: redundant vs chunking_state? */
5346 f.bdat_readers_wanted = FALSE;
5348 DATA_BDAT: /* Common code for DATA and BDAT */
5349 #ifndef DISABLE_PIPE_CONNECT
5350 fl.pipe_connect_acceptable = FALSE;
5352 if (!discarded && recipients_count <= 0)
5354 if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL)
5356 uschar *code = US"503";
5357 int len = Ustrlen(rcpt_smtp_response);
5358 smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
5360 /* Responses from smtp_printf() will have \r\n on the end */
5361 if (len > 2 && rcpt_smtp_response[len-2] == '\r')
5362 rcpt_smtp_response[len-2] = 0;
5363 smtp_respond(code, 3, FALSE, rcpt_smtp_response);
5365 if (f.smtp_in_pipelining_advertised && last_was_rcpt)
5366 smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE,
5367 smtp_names[smtp_connection_had[smtp_ch_index-1]]);
5369 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5370 smtp_connection_had[smtp_ch_index-1] == SCH_DATA
5371 ? US"valid RCPT command must precede DATA"
5372 : US"valid RCPT command must precede BDAT");
5374 if (chunking_state > CHUNKING_OFFERED)
5376 bdat_push_receive_functions();
5382 if (toomany && recipients_max_reject)
5384 sender_address = NULL; /* This will allow a new MAIL without RSET */
5385 sender_address_unrewritten = NULL;
5386 smtp_printf("554 Too many recipients\r\n", FALSE);
5388 if (chunking_state > CHUNKING_OFFERED)
5390 bdat_push_receive_functions();
5396 if (chunking_state > CHUNKING_OFFERED)
5397 rc = OK; /* No predata ACL or go-ahead output for BDAT */
5400 /* If there is an ACL, re-check the synchronization afterwards, since the
5401 ACL may have delayed. To handle cutthrough delivery enforce a dummy call
5402 to get the DATA command sent. */
5404 if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0)
5408 uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept";
5409 f.enable_dollar_recipients = TRUE;
5410 rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg,
5412 f.enable_dollar_recipients = FALSE;
5413 if (rc == OK && !check_sync())
5417 { /* Either the ACL failed the address, or it was deferred. */
5418 done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
5424 smtp_user_msg(US"354", user_msg);
5427 "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE);
5430 if (f.bdat_readers_wanted)
5431 bdat_push_receive_functions();
5434 if (smtp_in) /* all ACKs needed to ramp window up for bulk data */
5435 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
5436 US &on, sizeof(on));
5439 message_ended = END_NOTENDED; /* Indicate in middle of data */
5450 if (!(address = parse_extract_address(smtp_cmd_data, &errmess,
5451 &start, &end, &recipient_domain, FALSE)))
5453 smtp_printf("501 %s\r\n", FALSE, errmess);
5457 if (!recipient_domain)
5458 if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data,
5462 if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy,
5463 &user_msg, &log_msg)) != OK)
5464 done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg);
5468 address_item * addr = deliver_make_addr(address, FALSE);
5470 switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1,
5471 -1, -1, NULL, NULL, NULL))
5474 s = string_sprintf("250 <%s> is deliverable", address);
5478 s = (addr->user_message != NULL)?
5479 string_sprintf("451 <%s> %s", address, addr->user_message) :
5480 string_sprintf("451 Cannot resolve <%s> at this time", address);
5484 s = (addr->user_message != NULL)?
5485 string_sprintf("550 <%s> %s", address, addr->user_message) :
5486 string_sprintf("550 <%s> is not deliverable", address);
5487 log_write(0, LOG_MAIN, "VRFY failed for %s %s",
5488 smtp_cmd_argument, host_and_ident(TRUE));
5492 smtp_printf("%s\r\n", FALSE, s);
5500 rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg);
5502 done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg);
5505 BOOL save_log_testing_mode = f.log_testing_mode;
5506 f.address_test_mode = f.log_testing_mode = TRUE;
5507 (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
5508 smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
5510 f.address_test_mode = FALSE;
5511 f.log_testing_mode = save_log_testing_mode; /* true for -bh */
5520 if (!fl.tls_advertised)
5522 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5523 US"STARTTLS command used when not advertised");
5527 /* Apply an ACL check if one is defined */
5529 if ( acl_smtp_starttls
5530 && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls,
5531 &user_msg, &log_msg)) != OK
5534 done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg);
5538 /* RFC 2487 is not clear on when this command may be sent, though it
5539 does state that all information previously obtained from the client
5540 must be discarded if a TLS session is started. It seems reasonable to
5541 do an implied RSET when STARTTLS is received. */
5543 incomplete_transaction_log(US"STARTTLS");
5544 cancel_cutthrough_connection(TRUE, US"STARTTLS received");
5545 reset_point = smtp_reset(reset_point);
5547 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
5549 /* There's an attack where more data is read in past the STARTTLS command
5550 before TLS is negotiated, then assumed to be part of the secure session
5551 when used afterwards; we use segregated input buffers, so are not
5552 vulnerable, but we want to note when it happens and, for sheer paranoia,
5553 ensure that the buffer is "wiped".
5554 Pipelining sync checks will normally have protected us too, unless disabled
5555 by configuration. */
5557 if (receive_smtp_buffered())
5560 debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n");
5561 if (tls_in.active.sock < 0)
5562 smtp_inend = smtp_inptr = smtp_inbuffer;
5563 /* and if TLS is already active, tls_server_start() should fail */
5566 /* There is nothing we value in the input buffer and if TLS is successfully
5567 negotiated, we won't use this buffer again; if TLS fails, we'll just read
5568 fresh content into it. The buffer contains arbitrary content from an
5569 untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
5570 It seems safest to just wipe away the content rather than leave it as a
5571 target to jump to. */
5573 memset(smtp_inbuffer, 0, IN_BUFFER_SIZE);
5575 /* Attempt to start up a TLS session, and if successful, discard all
5576 knowledge that was obtained previously. At least, that's what the RFC says,
5577 and that's what happens by default. However, in order to work round YAEB,
5578 there is an option to remember the esmtp state. Sigh.
5580 We must allow for an extra EHLO command and an extra AUTH command after
5581 STARTTLS that don't add to the nonmail command count. */
5584 if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
5586 if (!tls_remember_esmtp)
5587 fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
5588 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
5589 cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE;
5590 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
5591 if (sender_helo_name)
5593 sender_helo_name = NULL;
5594 host_build_sender_fullhost(); /* Rebuild */
5595 set_process_info("handling incoming TLS connection from %s",
5596 host_and_ident(FALSE));
5599 (sender_host_address ? protocols : protocols_local)
5601 ? pextend + (sender_host_authenticated ? pauthed : 0)
5603 + (tls_in.active.sock >= 0 ? pcrpted : 0)
5606 sender_host_auth_pubname = sender_host_authenticated = NULL;
5607 authenticated_id = NULL;
5608 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
5609 DEBUG(D_tls) debug_printf("TLS active\n");
5610 break; /* Successful STARTTLS */
5613 (void) smtp_log_tls_fail(s);
5615 /* Some local configuration problem was discovered before actually trying
5616 to do a TLS handshake; give a temporary error. */
5620 smtp_printf("454 TLS currently unavailable\r\n", FALSE);
5624 /* Hard failure. Reject everything except QUIT or closed connection. One
5625 cause for failure is a nested STARTTLS, in which case tls_in.active remains
5626 set, but we must still reject all incoming commands. Another is a handshake
5627 failure - and there may some encrypted data still in the pipe to us, which we
5628 see as garbage commands. */
5630 DEBUG(D_tls) debug_printf("TLS failed to start\n");
5631 while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
5634 log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
5635 smtp_get_connection_info());
5636 smtp_notquit_exit(US"tls-failed", NULL, NULL);
5640 /* It is perhaps arguable as to which exit ACL should be called here,
5641 but as it is probably a situation that almost never arises, it
5642 probably doesn't matter. We choose to call the real QUIT ACL, which in
5643 some sense is perhaps "right". */
5648 && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
5649 &log_msg)) == ERROR))
5650 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
5653 smtp_respond(US"221", 3, TRUE, user_msg);
5655 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
5656 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
5657 smtp_get_connection_info());
5662 smtp_printf("554 Security failure\r\n", FALSE);
5665 tls_close(NULL, TLS_SHUTDOWN_NOWAIT);
5670 /* The ACL for QUIT is provided for gathering statistical information or
5671 similar; it does not affect the response code, but it can supply a custom
5675 smtp_quit_handler(&user_msg, &log_msg);
5681 smtp_rset_handler();
5682 cancel_cutthrough_connection(TRUE, US"RSET received");
5683 reset_point = smtp_reset(reset_point);
5690 smtp_printf("250 OK\r\n", FALSE);
5694 /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
5695 used, a check will be done for permitted hosts. Show STARTTLS only if not
5696 already in a TLS session and if it would be advertised in the EHLO
5701 smtp_printf("214-Commands supported:\r\n", TRUE);
5705 Ustrcat(buffer, US" AUTH");
5707 if (tls_in.active.sock < 0 &&
5708 verify_check_host(&tls_advertise_hosts) != FAIL)
5709 Ustrcat(buffer, US" STARTTLS");
5711 Ustrcat(buffer, US" HELO EHLO MAIL RCPT DATA BDAT");
5712 Ustrcat(buffer, US" NOOP QUIT RSET HELP");
5713 if (acl_smtp_etrn) Ustrcat(buffer, US" ETRN");
5714 if (acl_smtp_expn) Ustrcat(buffer, US" EXPN");
5715 if (acl_smtp_vrfy) Ustrcat(buffer, US" VRFY");
5716 smtp_printf("214%s\r\n", FALSE, buffer);
5722 incomplete_transaction_log(US"connection lost");
5723 smtp_notquit_exit(US"connection-lost", US"421",
5724 US"%s lost input connection", smtp_active_hostname);
5726 /* Don't log by default unless in the middle of a message, as some mailers
5727 just drop the call rather than sending QUIT, and it clutters up the logs.
5730 if (sender_address || recipients_count > 0)
5731 log_write(L_lost_incoming_connection, LOG_MAIN,
5732 "unexpected %s while reading SMTP command from %s%s%s D=%s",
5733 f.sender_host_unknown ? "EOF" : "disconnection",
5734 f.tcp_in_fastopen_logged
5737 ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO "
5739 host_and_ident(FALSE), smtp_read_error,
5740 string_timesince(&smtp_connection_start)
5744 log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s",
5745 smtp_get_connection_info(),
5746 f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"",
5748 string_timesince(&smtp_connection_start)
5759 done = synprot_error(L_smtp_protocol_error, 503, NULL,
5760 US"ETRN is not permitted inside a transaction");
5764 log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument,
5765 host_and_ident(FALSE));
5767 if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn,
5768 &user_msg, &log_msg)) != OK)
5770 done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg);
5774 /* Compute the serialization key for this command. */
5776 etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
5778 /* If a command has been specified for running as a result of ETRN, we
5779 permit any argument to ETRN. If not, only the # standard form is permitted,
5780 since that is strictly the only kind of ETRN that can be implemented
5781 according to the RFC. */
5783 if (smtp_etrn_command)
5787 etrn_command = smtp_etrn_command;
5788 deliver_domain = smtp_cmd_data;
5789 rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
5790 US"ETRN processing", &error);
5791 deliver_domain = NULL;
5794 log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s",
5796 smtp_printf("458 Internal failure\r\n", FALSE);
5801 /* Else set up to call Exim with the -R option. */
5805 if (*smtp_cmd_data++ != '#')
5807 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5808 US"argument must begin with #");
5811 etrn_command = US"exim -R";
5812 argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE,
5813 *queue_name ? 4 : 2,
5814 US"-R", smtp_cmd_data,
5815 US"-MCG", queue_name);
5818 /* If we are host-testing, don't actually do anything. */
5824 debug_printf("ETRN command is: %s\n", etrn_command);
5825 debug_printf("ETRN command execution skipped\n");
5827 if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE);
5828 else smtp_user_msg(US"250", user_msg);
5833 /* If ETRN queue runs are to be serialized, check the database to
5834 ensure one isn't already running. */
5836 if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1))
5838 smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data);
5842 /* Fork a child process and run the command. We don't want to have to
5843 wait for the process at any point, so set SIGCHLD to SIG_IGN before
5844 forking. It should be set that way anyway for external incoming SMTP,
5845 but we save and restore to be tidy. If serialization is required, we
5846 actually run the command in yet another process, so we can wait for it
5847 to complete and then remove the serialization lock. */
5849 oldsignal = signal(SIGCHLD, SIG_IGN);
5851 if ((pid = exim_fork(US"etrn-command")) == 0)
5853 smtp_input = FALSE; /* This process is not associated with the */
5854 (void)fclose(smtp_in); /* SMTP call any more. */
5855 (void)fclose(smtp_out);
5857 signal(SIGCHLD, SIG_DFL); /* Want to catch child */
5859 /* If not serializing, do the exec right away. Otherwise, fork down
5860 into another process. */
5862 if ( !smtp_etrn_serialize
5863 || (pid = exim_fork(US"etrn-serialised-command")) == 0)
5865 DEBUG(D_exec) debug_print_argv(argv);
5866 exim_nullstd(); /* Ensure std{in,out,err} exist */
5867 execv(CS argv[0], (char *const *)argv);
5868 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s",
5869 etrn_command, strerror(errno));
5870 _exit(EXIT_FAILURE); /* paranoia */
5873 /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That
5874 is, we are in the first subprocess, after forking again. All we can do
5875 for a failing fork is to log it. Otherwise, wait for the 2nd process to
5876 complete, before removing the serialization. */
5879 log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN "
5880 "failed: %s", strerror(errno));
5884 DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n",
5886 (void)wait(&status);
5887 DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n",
5891 enq_end(etrn_serialize_key);
5892 exim_underbar_exit(EXIT_SUCCESS);
5895 /* Back in the top level SMTP process. Check that we started a subprocess
5896 and restore the signal state. */
5900 log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s",
5902 smtp_printf("458 Unable to fork process\r\n", FALSE);
5903 if (smtp_etrn_serialize) enq_end(etrn_serialize_key);
5907 smtp_printf("250 OK\r\n", FALSE);
5909 smtp_user_msg(US"250", user_msg);
5911 signal(SIGCHLD, oldsignal);
5916 done = synprot_error(L_smtp_syntax_error, 501, NULL,
5917 US"unexpected argument data");
5921 /* This currently happens only for NULLs, but could be extended. */
5924 done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */
5925 US"NUL character(s) present (shown as '?')");
5926 smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n",
5933 if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE)
5934 smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1;
5935 c = smtp_inend - smtp_inptr;
5936 if (c > 150) c = 150; /* limit logged amount */
5938 incomplete_transaction_log(US"sync failure");
5939 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
5940 "(next input sent too soon: pipelining was%s advertised): "
5941 "rejected \"%s\" %s next input=\"%s\"",
5942 f.smtp_in_pipelining_advertised ? "" : " not",
5943 smtp_cmd_buffer, host_and_ident(TRUE),
5944 string_printing(smtp_inptr));
5945 smtp_notquit_exit(US"synchronization-error", US"554",
5946 US"SMTP synchronization error");
5947 done = 1; /* Pretend eof - drops connection */
5951 case TOO_MANY_NONMAIL_CMD:
5952 s = smtp_cmd_buffer;
5953 while (*s != 0 && !isspace(*s)) s++;
5954 incomplete_transaction_log(US"too many non-mail commands");
5955 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5956 "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
5957 (int)(s - smtp_cmd_buffer), smtp_cmd_buffer);
5958 smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
5959 done = 1; /* Pretend eof - drops connection */
5962 #ifdef SUPPORT_PROXY
5963 case PROXY_FAIL_IGNORE_CMD:
5964 smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE);
5969 if (unknown_command_count++ >= smtp_max_unknown_commands)
5971 log_write(L_smtp_syntax_error, LOG_MAIN,
5972 "SMTP syntax error in \"%s\" %s %s",
5973 string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
5974 US"unrecognized command");
5975 incomplete_transaction_log(US"unrecognized command");
5976 smtp_notquit_exit(US"bad-commands", US"500",
5977 US"Too many unrecognized commands");
5979 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
5980 "unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
5981 string_printing(smtp_cmd_buffer));
5984 done = synprot_error(L_smtp_syntax_error, 500, NULL,
5985 US"unrecognized command");
5989 /* This label is used by goto's inside loops that want to break out to
5990 the end of the command-processing loop. */
5993 last_was_rej_mail = was_rej_mail; /* Remember some last commands for */
5994 last_was_rcpt = was_rcpt; /* protocol error handling */
5998 return done - 2; /* Convert yield values */
6004 authres_smtpauth(gstring * g)
6006 if (!sender_host_authenticated)
6009 g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname);
6011 if (Ustrcmp(sender_host_auth_pubname, "tls") == 0)
6012 g = authenticated_id
6013 ? string_append(g, 2, US") x509.auth=", authenticated_id)
6014 : string_cat(g, US") reason=x509.auth");
6016 g = authenticated_id
6017 ? string_append(g, 2, US") smtp.auth=", authenticated_id)
6018 : string_cat(g, US", no id saved)");
6020 if (authenticated_sender)
6021 g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender);
6029 /* End of smtp_in.c */